WorldWideScience

Sample records for model lessons observe

  1. Lessons Learned About Organic Aerosol Formation in the Southeast U.S. Using Observations and Modeling

    Science.gov (United States)

    Isoprene emitted by vegetation is an important precursor of secondary organic aerosol (SOA). In this work, modeling of isoprene SOA via heterogeneous uptake is explored and compared to observations from the Southern Oxidant and Aerosol Study (SOAS).

  2. The Lesson Observation On-Line (Evidence Portfolio) Platform

    Science.gov (United States)

    Cooper, David G.

    2015-01-01

    At a time when teacher training is being moved to school-based programmes it is important to engage in a research-informed dialogue about creating more distinctive, and cost-effective 21st century models of teacher training. Three years ago I began feasibility field testing the Lesson Observation On-line (Evidence Portfolio) Platform [LOOP]…

  3. Demonstration lessons in mathematics education: teachers' observation foci and intended changes in practice

    Science.gov (United States)

    Clarke, Doug; Roche, Anne; Wilkie, Karina; Wright, Vince; Brown, Jill; Downton, Ann; Horne, Marj; Knight, Rose; McDonough, Andrea; Sexton, Matthew; Worrall, Chris

    2013-06-01

    As part of a teacher professional learning project in mathematics education, university mathematics educators taught demonstration lessons in project primary schools. These lessons were part of a "pre-brief, teaching, and debrief" process, in which up to eight teachers observed each lesson. Using brief questionnaires completed in advance of the lesson, during the lesson, following the debrief, and several weeks later, data were collected on teachers' intended and actual observation foci and any anticipated changes in their beliefs and practices arising from the experience. There were several common themes in teachers' intended observations, including a focus on questioning, catering for individual differences, and building student engagement. As evident in other research, teachers' intended and actual observations gave greater attention to teacher actions and decision making than to student learning and thinking. In this paper, we situate demonstration lessons within teacher professional learning models, describe the features of our model, summarise teacher data, and discuss issues arising from our work.

  4. Connections between simulations and observation in climate computer modeling. Scientist's practices and "bottom-up epistemology" lessons

    Science.gov (United States)

    Guillemot, Hélène

    Climate modeling is closely tied, through its institutions and practices, to observations from satellites and to the field sciences. The validity, quality and scientific credibility of models are based on interaction between models and observation data. In the case of numerical modeling of climate and climate change, validation is not solely a scientific interest: the legitimacy of computer modeling, as a tool of knowledge, has been called into question in order to deny the reality of any anthropogenic climate change; model validations thereby bring political issues into play as well. There is no systematic protocol of validation: one never validates a model in general, but the capacity of a model to account for a defined climatic phenomenon or characteristic. From practices observed in the two research centers developing and using a climate model in France, this paper reviews different ways in which the researchers establish links between models and empirical data (which are not reduced to the latter validating the former) and convince themselves that their models are valid. The analysis of validation practices-relating to parametrization, modes of variability, climatic phenomena, etc.-allows us to highlight some elements of the epistemology of modeling.

  5. Learning to observe mathematical learning in lesson studies

    DEFF Research Database (Denmark)

    Rasmussen, Klaus; Østergaard, Camilla Hellsten; Foss, Kristian Kildemoes

    2016-01-01

    This poster deals with lesson study (LS) in pre-service teacher education. In particular how to prepare for, carry out, and reflect upon, observations of pupil learning. Observation is of crucial importance to the lesson study process, and here we present a study of observation features which...... enable or hinder fruitful lesson study. While substantial research has been carried out in the general field of bserving pupils’ learning processes and teachers’ pedagogical practice, little is known about this in the particular setting of lesson study....

  6. Very Large System Dynamics Models - Lessons Learned

    Energy Technology Data Exchange (ETDEWEB)

    Jacob J. Jacobson; Leonard Malczynski

    2008-10-01

    This paper provides lessons learned from developing several large system dynamics (SD) models. System dynamics modeling practice emphasize the need to keep models small so that they are manageable and understandable. This practice is generally reasonable and prudent; however, there are times that large SD models are necessary. This paper outlines two large SD projects that were done at two Department of Energy National Laboratories, the Idaho National Laboratory and Sandia National Laboratories. This paper summarizes the models and then discusses some of the valuable lessons learned during these two modeling efforts.

  7. Refining MARGINS Mini-Lessons Using Classroom Observations

    Science.gov (United States)

    Iverson, E. A.; Manduca, C. A.; McDaris, J. R.; Lee, S.

    2009-12-01

    One of the challenges that we face in developing teaching materials or activities from research findings is testing the materials to determine that they work as intended. Traditionally faculty develop material for their own class, notice what worked and didn’t, and improve them the next year. However, as we move to a community process of creating and sharing teaching materials, a community-based process for testing materials is appropriate. The MARGINS project has piloted such a process for testing teaching materials and activities developed as part of its mini-lesson project (http://serc.carleton.edu/margins/index.html). Building on prior work developing mechanisms for community review of teaching resources (e.g. Kastens, 2002; Hancock and Manduca, 2005; Mayhew and Hall, 2007), the MARGINS evaluation team developed a structured classroom observation protocol. The goals of field testing are to a) gather structured, consistent feedback for the lesson authors based on classroom use; b) guide reviewers of these lessons to reflect on research-based educational practice as a framework for their comments; c) collect information on the data and observations that the reviewer used to underpin their review; d) determine which mini-lessons are ready to be made widely available on the website. The protocol guides faculty observations on why they used the activity, the effectiveness of the activity in their classroom, the success of the activity in leading to the desired learning, and what other faculty need to successfully use the activity. Available online (http://serc.carleton.edu/margins/protocol.html), the protocol can be downloaded and completed during instruction with the activity. In order to encourage review of mini-lessons using the protocol, a workshop focused on review and revision of activities was held in May 2009. In preparation for the workshop, 13 of the 28 participants chose to field test a mini-lesson prior to the workshop and reported that they found this

  8. Concert Programming and Performing as a Model for Lesson Planning and Teaching

    Science.gov (United States)

    Branscome, Eric E.

    2014-01-01

    For many novice music teachers, creating and implementing effective music lessons can be a tedious process. Moreover, preparing a music lesson is quite different from lesson planning in other areas, creating a disconnect that music educators may feel when trying to make music lessons fit a classroom lesson-plan model. However, most music teachers…

  9. A Model of Microteaching Lesson Study Implementation in the Prospective History Teacher Education

    Science.gov (United States)

    Utami, Indah Wahyu Puji; Mashuri; Nafi'ah, Ulfatun

    2016-01-01

    Microteaching lesson study is a model to improve prospective teacher quality by incorporating several element of microteaching and lesson study. This study concern on the implementation of microteaching lesson study in prospective history teacher education. Microteaching lesson study model implemented in this study consist of three stages: plan,…

  10. LCROSS (Lunar Crater Observation and Sensing Satellite) Observation Campaign: Strategies, Implementation, and Lessons Learned

    Science.gov (United States)

    Heldmann, Jennifer L.; Colaprete, Anthony; Wooden, Diane H.; Ackermann, Robert F.; Acton, David D.; Backus, Peter R.; Bailey, Vanessa; Ball, Jesse G.; Barott, William C.; Blair, Samantha K.; Buie, Marc W.; Callahan, Shawn; Chanover, Nancy J.; Choi, Young-Jun; Conrad, Al; Coulson, Dolores M.; Crawford, Kirk B.; DeHart, Russell; de Pater, Imke; Disanti, Michael; Forster, James R.; Furusho, Reiko; Fuse, Tetsuharu; Geballe, Tom; Gibson, J. Duane; Goldstein, David; Gregory, Stephen A.; Gutierrez, David J.; Hamilton, Ryan T.; Hamura, Taiga; Harker, David E.; Harp, Gerry R.; Haruyama, Junichi; Hastie, Morag; Hayano, Yutaka; Hinz, Phillip; Hong, Peng K.; James, Steven P.; Kadono, Toshihiko; Kawakita, Hideyo; Kelley, Michael S.; Kim, Daryl L.; Kurosawa, Kosuke; Lee, Duk-Hang; Long, Michael; Lucey, Paul G.; Marach, Keith; Matulonis, Anthony C.; McDermid, Richard M.; McMillan, Russet; Miller, Charles; Moon, Hong-Kyu; Nakamura, Ryosuke; Noda, Hirotomo; Okamura, Natsuko; Ong, Lawrence; Porter, Dallan; Puschell, Jeffery J.; Rayner, John T.; Rembold, J. Jedadiah; Roth, Katherine C.; Rudy, Richard J.; Russell, Ray W.; Ryan, Eileen V.; Ryan, William H.; Sekiguchi, Tomohiko; Sekine, Yasuhito; Skinner, Mark A.; Sôma, Mitsuru; Stephens, Andrew W.; Storrs, Alex; Suggs, Robert M.; Sugita, Seiji; Sung, Eon-Chang; Takatoh, Naruhisa; Tarter, Jill C.; Taylor, Scott M.; Terada, Hiroshi; Trujillo, Chadwick J.; Vaitheeswaran, Vidhya; Vilas, Faith; Walls, Brian D.; Watanabe, Jun-ihi; Welch, William J.; Woodward, Charles E.; Yim, Hong-Suh; Young, Eliot F.

    2012-05-01

    NASA's LCROSS (Lunar Crater Observation and Sensing Satellite) mission was designed to explore the nature of previously detected enhanced levels of hydrogen near the lunar poles. The LCROSS mission impacted the spent upper stage of the launch vehicle into a permanently shadowed region of the lunar surface to create an ejecta plume. The resultant impact crater and plume were then observed by the LCROSS Shepherding Spacecraft as well as a cadre of telescopes on the Earth and in space to determine the nature of the materials contained within the permanently shadowed region. The Shepherding Spacecraft then became a second impactor which was also observed by multiple assets. The LCROSS Observation Campaign was a key component of the LCROSS mission. The goal of the Observation Campaign was to realize the scientific benefits of extending the LCROSS observations to multiple ground and space-based assets. This paper describes the LCROSS Observation Campaign and provides an overview of the Campaign coordination and logistics as well as a summary of the observation techniques utilized at a multitude of observatories. Lessons learned from the LCROSS Observation Campaign are also discussed to assist with the planning of future unique observing events.

  11. Satlc model lesson for teaching and learning complex ...

    African Journals Online (AJOL)

    Satlc model lesson for teaching and learning complex environmental issues related to the ... In the absence of necessary input of biological sciences, mathematics, ... Recently concept based teaching methodology; namely systemic approach to ... By Country · List All Titles · Open Access Titles This Journal is Open Access.

  12. Making Connections to the "Real World": A Model Building Lesson

    Science.gov (United States)

    Horibe, Shusaku; Underwood, Bret

    2009-01-01

    Classroom activities that include the process of model building, in which students build simplified physical representations of a system, have the potential to help students make meaningful connections between physics and the real world. We describe a lesson designed with this intent for an introductory college classroom that engages students in…

  13. Individual Colorimetric Observer Model.

    Directory of Open Access Journals (Sweden)

    Yuta Asano

    Full Text Available This study proposes a vision model for individual colorimetric observers. The proposed model can be beneficial in many color-critical applications such as color grading and soft proofing to assess ranges of color matches instead of a single average match. We extended the CIE 2006 physiological observer by adding eight additional physiological parameters to model individual color-normal observers. These eight parameters control lens pigment density, macular pigment density, optical densities of L-, M-, and S-cone photopigments, and λmax shifts of L-, M-, and S-cone photopigments. By identifying the variability of each physiological parameter, the model can simulate color matching functions among color-normal populations using Monte Carlo simulation. The variabilities of the eight parameters were identified through two steps. In the first step, extensive reviews of past studies were performed for each of the eight physiological parameters. In the second step, the obtained variabilities were scaled to fit a color matching dataset. The model was validated using three different datasets: traditional color matching, applied color matching, and Rayleigh matches.

  14. "Give 'Em the Old Razzle Dazzle"--Surviving the Lesson Observation Process in Further Education

    Science.gov (United States)

    Thompson, Carol A.; Wolstencroft, Peter

    2014-01-01

    This paper examines the key role that graded lesson observations have within the measurement of quality in the post-compulsory education sector. Using semi-structured interviews, it looks at their impact on participants and also their execution in light of their stated purpose to "improve teaching and learning". The sample selected…

  15. Geomagnetic Observations and Models

    CERN Document Server

    Mandea, Mioara

    2011-01-01

    This volume provides comprehensive and authoritative coverage of all the main areas linked to geomagnetic field observation, from instrumentation to methodology, on ground or near-Earth. Efforts are also focused on a 21st century e-Science approach to open access to all geomagnetic data, but also to the data preservation, data discovery, data rescue, and capacity building. Finally, modeling magnetic fields with different internal origins, with their variation in space and time, is an attempt to draw together into one place the traditional work in producing models as IGRF or describing the magn

  16. Space weathering of asteroids: Lessons from Itokawa for future observations

    Science.gov (United States)

    Sasaki, Sho; HIroi, Takahiro

    2016-07-01

    weathered. The presence of opposition effect in rocky terrain of Itokawa suggested that the surface would be covered by particulate materials or porous enough to scatter light. Spectral variations were observed, that can be explained by Hapke's space weathering model, where the amount of npFe0 controls spectral reddening. As for color variation of Itokawa, we can interpret that seismic shaking caused by impacts or planetary encounters should lead to exposure of underlying relatively fresh bright area by removing weathered darker boulder-rich layer. Itokawa - Evidence from Returned Samples In 2011, HAYABUSA returned more than 1000 particulate samples of Itokawa back to the Earth. Analysis of mineral assemblies and composition of Itokawa particles supports that Itokawa has LL-chondrite composition. The most notable discoveries in Itokawa particles is amorphous space-weathering rims containing npFe0 16, 17, 18). Sometimes ion-implanted type-II layers contains vesicles, probably due mainly to trapping solar wind energetic helium with penetration depth up to a few tens µm (composite vesicular rim in 17, 18)). Large vesicles are observed as blisters on the surface of Itokawa particles. Matsumoto et al. 18) identified space weathered rims with blisters on eleven out of twenty regolith particles of Itokawa. It was confirmed that a blister corresponds to a vesicle in npFe0-bearing amorphous layer. These rims with blisters are heterogeneously distributed even in one particle. Sometimes blistered rims are observed in opposite surfaces of the same particle. This is a strong evidence of regolith mixing. So far, there is no correlation between the blister distribution and surface morphologies such as roundness of particles. A few 10 nm amorphous rim can be developed in timescale 1000 yr (based on solar flare density, Regolith mixing processes may prolong timescale of optical maturation on smooth regions of Itokawa. References 1) Hapke B., Cassidy, W. And Wells. E.: Effects of vapor

  17. Observed lesson structure during the first year of secondary education : Exploration of change and link with academic engagement

    NARCIS (Netherlands)

    Maulana, Ridwan; Opdenakker, Marie-Christine; Stroet, Kim; Bosker, Roel

    2012-01-01

    This study investigates whether lesson structure (LS) matters and which components are important for academic engagement during the first grade of secondary education. Data from videoed lessons of 10 Dutch and 12 Indonesian teachers analyzed using an observation protocol show that six LS components

  18. Assessing pre-service science teachers' technological pedagogical content knowledge (TPACK) through observations and lesson plans

    Science.gov (United States)

    Canbazoglu Bilici, Sedef; Selcen Guzey, S.; Yamak, Havva

    2016-05-01

    Background: Technological pedagogical content knowledge (TPACK) is critical for effective teaching with technology. However, generally science teacher education programs do not help pre-service teachers develop TPACK. Purpose: The purpose of this study was to assess pre-service science teachers' TPACK over a semester-long Science Methods. Sample: Twenty-seven pre-service science teachers took the course toward the end of their four-year teacher education program. Design and method: The study employed the case study methodology. Lesson plans and microteaching observations were used as data collection tools. Technological Pedagogical Content Knowledge-based lesson plan assessment instrument (TPACK-LpAI) and Technological Pedagogical Content Knowledge Observation Protocol (TPACK-OP) were used to analyze data obtained from observations and lesson plans. Results: The results showed that the TPACK-focused Science Methods course had an impact on pre-service teachers' TPACK to varying degrees. Most importantly, the course helped teachers gain knowledge of effective usage of educational technology tools. Conclusion: Teacher education programs should provide opportunities to pre-service teachers to develop their TPACK so that they can effectively integrate technology into their teaching.

  19. The Couplex test cases: models and lessons

    Energy Technology Data Exchange (ETDEWEB)

    Bourgeat, A. [Lyon-1 Univ., MCS, 69 - Villeurbanne (France); Kern, M. [Institut National de Recherches Agronomiques (INRA), 78 - Le Chesnay (France); Schumacher, S.; Talandier, J. [Agence Nationale pour la Gestion des Dechets Radioactifs (ANDRA), 92 - Chatenay Malabry (France)

    2003-07-01

    The Couplex test cases are a set of numerical test models for nuclear waste deep geological disposal simulation. They are centered around the numerical issues arising in the near and far field transport simulation. They were used in an international contest, and are now becoming a reference in the field. We present the models used in these test cases, and show sample results from the award winning teams. (authors)

  20. Autophagy and aging: lessons from progeria models.

    Science.gov (United States)

    Mariño, Guillermo; Fernández, Alvaro F; López-Otín, Carlos

    2010-01-01

    Autophagy is an evolutionarily conserved process essential for cellular homeostasis and organismal viability. In fact, this pathway is one of the major protein degradation mechanisms in eukaryotic cells. It has been repeatedly reported that the autophagic activity of living cells decreases with age, probably contributing to the accumulation of damaged macromolecules and organelles during aging. Moreover, autophagy modulation in different model organisms has yielded very promising results suggesting that the maintenance of a proper autophagic activity contributes to extend longevity. On the other hand, recent findings have shown that distinct premature-aging murine models exhibit an extensive basal activation of autophagy instead of the characteristic decline in this process occurring during normal aging. This unexpected autophagic increase in progeroid models is usually associated with a series of metabolic alterations resembling those occurring under calorie restriction or in other situations reported to prolong life-span. In this chapter, we will discuss the current knowledge on the relationship between the autophagy pathway and aging with a special emphasis on the unexpected and novel link between premature aging and autophagy up-regulation.

  1. Inductive & Deductive Science Thinking: A Model for Lesson Development

    Science.gov (United States)

    Bilica, Kim; Flores, Margaret

    2009-01-01

    Middle school students make great learning gains when they participate in lessons that invite them to practice their developing scientific reasoning skills; however, designing developmentally appropriate, clear, and structured lessons about scientific thinking and reasoning can be difficult. This challenge can be met through lessons that teach…

  2. The implementation of discovery learning model based on lesson study to increase student's achievement in colloid

    Science.gov (United States)

    Suyanti, Retno Dwi; Purba, Deby Monika

    2017-03-01

    The objectives of this research are to get the increase student's achievement on the discovery learning model based on lesson study. Beside of that, this research also conducted to know the cognitive aspect. This research was done in three school that are SMA N 3 Medan. Population is all the students in SMA N 11 Medan which taken by purposive random sampling. The research instruments are achievement test instruments that have been validated. The research data analyzed by statistic using Ms Excell. The result data shows that the student's achievement taught by discovery learning model based on Lesson study higher than the student's achievement taught by direct instructional method. It can be seen from the average of gain and also proved with t-test, the normalized gain in experimental class of SMA N 11 is (0.74±0.12) and control class (0.45±0.12), at significant level α = 0.05, Ha is received and Ho is refused where tcount>ttable in SMA N 11 (9.81>1,66). Then get the improvement cognitive aspect from three of school is C2 where SMA N 11 is 0.84(high). Then the observation sheet result of lesson study from SMA N 11 92 % of student working together while 67% less in active using media.

  3. Shelter models and observations

    DEFF Research Database (Denmark)

    Peña, Alfredo; Bechmann, Andreas; Conti, Davide;

    This report documents part of the work performed by work package (WP) 3 of the ‘Online WAsP’ project funded by the Danish Energy Technology and Demonstration Program (EUDP). WP3 initially identified the shortcomings of the current WAsP engine for small and medium wind turbines (Peña et al., 2014b...... in the wake of a fence. The experiment is the basis of the study of the error and uncertainty of the obstacle models....

  4. A GUIDED SWAT MODEL APPLICATION ON SEDIMENT YIELD MODELING IN PANGANI RIVER BASIN: LESSONS LEARNT

    Directory of Open Access Journals (Sweden)

    Preksedis Marco Ndomba

    2008-12-01

    Full Text Available The overall objective of this paper is to report on the lessons learnt from applying Soil and Water Assessment Tool (SWAT in a well guided sediment yield modelling study. The study area is the upstream of Pangani River Basin (PRB, the Nyumba Ya Mungu (NYM reservoir catchment, located in the North Eastern part of Tanzania. It should be noted that, previous modeling exercises in the region applied SWAT with preassumption that inter-rill or sheet erosion was the dominant erosion type. In contrast, in this study SWAT model application was guided by results of analysis of high temporal resolution of sediment flow data and hydro-meteorological data. The runoff component of the SWAT model was calibrated from six-years (i.e. 1977–1982 of historical daily streamflow data. The sediment component of the model was calibrated using one-year (1977–1988 daily sediment loads estimated from one hydrological year sampling programme (between March and November, 2005 rating curve. A long-term period over 37 years (i.e. 1969–2005 simulation results of the SWAT model was validated to downstream NYM reservoir sediment accumulation information. The SWAT model captured 56 percent of the variance (CE and underestimated the observed daily sediment loads by 0.9 percent according to Total Mass Control (TMC performance indices during a normal wet hydrological year, i.e., between November 1, 1977 and October 31, 1978, as the calibration period. SWAT model predicted satisfactorily the long-term sediment catchment yield with a relative error of 2.6 percent. Also, the model has identified erosion sources spatially and has replicated some erosion processes as determined in other studies and field observations in the PRB. This result suggests that for catchments where sheet erosion is dominant SWAT model may substitute the sediment-rating curve. However, the SWAT model could not capture the dynamics of sediment load delivery in some seasons to the catchment outlet.

  5. A GUIDED SWAT MODEL APPLICATION ON SEDIMENT YIELD MODELING IN PANGANI RIVER BASIN: LESSONS LEARNT

    Directory of Open Access Journals (Sweden)

    Preksedis M. Ndomba

    2008-01-01

    Full Text Available The overall objective of this paper is to report on the lessons learnt from applying Soil and Water Assessment Tool (SWAT in a well guided sediment yield modelling study. The study area is the upstream of Pangani River Basin (PRB, the Nyumba Ya Mungu (NYM reservoir catchment, located in the North Eastern part of Tanzania. It should be noted that, previous modeling exercises in the region applied SWAT with preassumption that inter-rill or sheet erosion was the dominant erosion type. In contrast, in this study SWAT model application was guided by results of analysis of high temporal resolution of sediment flow data and hydro-meteorological data. The runoff component of the SWAT model was calibrated from six-years (i.e. 1977¿1982 of historical daily streamflow data. The sediment component of the model was calibrated using one-year (1977-1988 daily sediment loads estimated from one hydrological year sampling programme (between March and November, 2005 rating curve. A long-term period over 37 years (i.e. 1969-2005 simulation results of the SWAT model was validated to downstream NYM reservoir sediment accumulation information. The SWAT model captured 56 percent of the variance (CE and underestimated the observed daily sediment loads by 0.9 percent according to Total Mass Control (TMC performance indices during a normal wet hydrological year, i.e., between November 1, 1977 and October 31, 1978, as the calibration period. SWAT model predicted satisfactorily the long-term sediment catchment yield with a relative error of 2.6 percent. Also, the model has identified erosion sources spatially and has replicated some erosion processes as determined in other studies and field observations in the PRB. This result suggests that for catchments where sheet erosion is dominant SWAT model may substitute the sediment-rating curve. However, the SWAT model could not capture the dynamics of sediment load delivery in some seasons to the catchment outlet.

  6. A new approach to managing Lessons Learned in PMBoK process groups: the Ballistic 2.0 Model

    OpenAIRE

    Marcirio Chaves; Cíntia Araújo; Laura Teixeira; Debora Rosa; Irapuan Júnior

    2016-01-01

    In any organization, dealing with lessons learned is a complex issue that involves people, processes and technologies. Although lessons learned processes are already well established in the project management community, the use of modern web technologies to support them is still in its infancy. This paper introduces a new model to manage lessons learned in PMBoK process groups. This model draws upon interdisciplinary literature, which embeds lessons learned processes, shared context and Web 2...

  7. Within-Year Changes of Lesson Structure: An Exploration of Pedagogical Functions of Lessons by Means of Multilevel Growth Curve Modelling in Indonesia

    Science.gov (United States)

    Maulana, Ridwan; Opdenakker, Marie-Christine; den Brok, Perry

    2015-01-01

    Teaching is undoubtedly complex and the complexity of classroom practice implies that the structure of lessons making up teaching may differ and subject to change over time. The aims of this study were to investigate changes in observed lesson structure, and explore the effects of several teacher and contextual characteristics on differences in…

  8. DMPD: Infectious non-self recognition in invertebrates: lessons from Drosophila andother insect models. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 15476918 Infectious non-self recognition in invertebrates: lessons from Drosophila ...fectious non-self recognition in invertebrates: lessons from Drosophila andother insect models. PubmedID 154...76918 Title Infectious non-self recognition in invertebrates: lessons from Drosop

  9. Video observation in HIT development: lessons learned on benefits and challenges.

    Science.gov (United States)

    Høstgaard, Anna Marie; Bertelsen, Pernille

    2012-08-22

    Experience shows that the precondition for the development of successful health information technologies is a thorough insight into clinical work practice. In contemporary clinical work practice, clinical work and health information technology are integrated, and part of the practice is tacit. When work practice becomes routine, it slips to the background of the conscious awareness and becomes difficult to recognize without the context to support recall. This means that it is difficult to capture with traditional ethnographic research methods or in usability laboratories or clinical set ups. Observation by the use of the video technique within healthcare settings has proven to be capable of providing a thorough insight into the complex clinical work practice and its context - including parts of the tacit practice. The objective of this paper is 1) to argue for the video observation technique to inform and improve health-information-technology development and 2) to share insights and lessons learned on benefits and challenges when using the video observation technique within healthcare settings. A multiple case study including nine case studies conducted by DaCHI researchers 2004-2011 using audio-visual, non-participant video observation for data collection within different healthcare settings. In HIT development, video observation is beneficial for 1) informing and improving system design 2) studying changes in work practice 3) identifying new potentials and 4) documenting current work practices. The video observation technique used within healthcare settings is superior to other ethnographic research methods when it comes to disclosing the complexity in clinical work practice. The insights gained are far more realistic compared to traditional ethnographic studies or usability studies and studies in clinical set ups. Besides, the data generated through video recordings provide a solid basis for dialog between the health care professionals involved. The most

  10. Video observation in HIT development: lessons learned on benefits and challenges

    Directory of Open Access Journals (Sweden)

    Høstgaard Anna

    2012-08-01

    Full Text Available Abstract Background Experience shows that the precondition for the development of successful health information technologies is a thorough insight into clinical work practice. In contemporary clinical work practice, clinical work and health information technology are integrated, and part of the practice is tacit. When work practice becomes routine, it slips to the background of the conscious awareness and becomes difficult to recognize without the context to support recall. This means that it is difficult to capture with traditional ethnographic research methods or in usability laboratories or clinical set ups. Observation by the use of the video technique within healthcare settings has proven to be capable of providing a thorough insight into the complex clinical work practice and its context - including parts of the tacit practice. The objective of this paper is 1 to argue for the video observation technique to inform and improve health-information-technology development and 2 to share insights and lessons learned on benefits and challenges when using the video observation technique within healthcare settings. Methods A multiple case study including nine case studies conducted by DaCHI researchers 2004–2011 using audio-visual, non-participant video observation for data collection within different healthcare settings. Results In HIT development, video observation is beneficial for 1 informing and improving system design 2 studying changes in work practice 3 identifying new potentials and 4 documenting current work practices. Conclusions The video observation technique used within healthcare settings is superior to other ethnographic research methods when it comes to disclosing the complexity in clinical work practice. The insights gained are far more realistic compared to traditional ethnographic studies or usability studies and studies in clinical set ups. Besides, the data generated through video recordings provide a solid basis for dialog

  11. Medical Logistics Lessons Observed During Operations Enduring Freedom and Iraqi Freedom.

    Science.gov (United States)

    Dole, Mark J; Kissane, Jonathan M

    2016-01-01

    Medical Logistics (MEDLOG) is a function of the Army's integrated System for Health that provides the medical products and specialized logistics services required to deliver health protection and care under all operational conditions. In unified land operations, MEDLOG is an inherent function of Health Service Support (HSS), which also includes casualty care and medical evacuation. This paper focuses on a few key lessons observed during Operations Enduring Freedom and Iraqi Freedom with direct implications for the support of HSS in future operations as envisioned in the Army Operating Concept and the Joint Concept for Health Services. It also examines a few key enablers that helped mitigate these challenges that are not yet fully acknowledged in Army Medical Department doctrine, policy, and planning.

  12. Test Driven Development: Lessons from a Simple Scientific Model

    Science.gov (United States)

    Clune, T. L.; Kuo, K.

    2010-12-01

    In the commercial software industry, unit testing frameworks have emerged as a disruptive technology that has permanently altered the process by which software is developed. Unit testing frameworks significantly reduce traditional barriers, both practical and psychological, to creating and executing tests that verify software implementations. A new development paradigm, known as test driven development (TDD), has emerged from unit testing practices, in which low-level tests (i.e. unit tests) are created by developers prior to implementing new pieces of code. Although somewhat counter-intuitive, this approach actually improves developer productivity. In addition to reducing the average time for detecting software defects (bugs), the requirement to provide procedure interfaces that enable testing frequently leads to superior design decisions. Although TDD is widely accepted in many software domains, its applicability to scientific modeling still warrants reasonable skepticism. While the technique is clearly relevant for infrastructure layers of scientific models such as the Earth System Modeling Framework (ESMF), numerical and scientific components pose a number of challenges to TDD that are not often encountered in commercial software. Nonetheless, our experience leads us to believe that the technique has great potential not only for developer productivity, but also as a tool for understanding and documenting the basic scientific assumptions upon which our models are implemented. We will provide a brief introduction to test driven development and then discuss our experience in using TDD to implement a relatively simple numerical model that simulates the growth of snowflakes. Many of the lessons learned are directly applicable to larger scientific models.

  13. Observations involving broadband impedance modelling

    Energy Technology Data Exchange (ETDEWEB)

    Berg, J.S. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)

    1996-08-01

    Results for single- and multi-bunch instabilities can be significantly affected by the precise model that is used for the broadband impedance. This paper discusses three aspects of broadband impedance modelling. The first is an observation of the effect that a seemingly minor change in an impedance model has on the single-bunch mode coupling threshold. The second is a successful attempt to construct a model for the high-frequency tails of an r.f. cavity. The last is a discussion of requirements for the mathematical form of an impedance which follow from the general properties of impedances. (author)

  14. Observations involving broadband impedance modelling

    Energy Technology Data Exchange (ETDEWEB)

    Berg, J.S.

    1995-08-01

    Results for single- and multi-bunch instabilities can be significantly affected by the precise model that is used for the broadband impendance. This paper discusses three aspects of broadband impendance modeling. The first is an observation of the effect that a seemingly minor change in an impedance model has on the single-bunch mode coupling threshold. The second is a successful attempt to construct a model for the high-frequency tails of an r.f cavity. The last is a discussion of requirements for the mathematical form of an impendance which follow from the general properties of impendances.

  15. Advancing waterborne pathogen modelling: lessons from global nutrient export models

    NARCIS (Netherlands)

    Vermeulen, L.C.; Hofstra, N.; Kroeze, C.; Medema, G.J.

    2015-01-01

    Waterborne pathogens cause health problems worldwide. A global waterborne pathogen model could provide valuable new insights for data-sparse regions, by identifying pathogen hotspots and evaluating global change and risk management scenarios. Global waterborne pathogen modelling is not as advanced a

  16. Modeling conflict : research methods, quantitative modeling, and lessons learned.

    Energy Technology Data Exchange (ETDEWEB)

    Rexroth, Paul E.; Malczynski, Leonard A.; Hendrickson, Gerald A.; Kobos, Peter Holmes; McNamara, Laura A.

    2004-09-01

    This study investigates the factors that lead countries into conflict. Specifically, political, social and economic factors may offer insight as to how prone a country (or set of countries) may be for inter-country or intra-country conflict. Largely methodological in scope, this study examines the literature for quantitative models that address or attempt to model conflict both in the past, and for future insight. The analysis concentrates specifically on the system dynamics paradigm, not the political science mainstream approaches of econometrics and game theory. The application of this paradigm builds upon the most sophisticated attempt at modeling conflict as a result of system level interactions. This study presents the modeling efforts built on limited data and working literature paradigms, and recommendations for future attempts at modeling conflict.

  17. Modeling Human Glaucoma: Lessons from the in vitro Models.

    Science.gov (United States)

    Aires, Inês Dinis; Ambrósio, António Francisco; Santiago, Ana Raquel

    2017-01-01

    Glaucoma, a leading cause of blindness worldwide, is a degenerative disease characterized by retinal ganglion cell (RGC) loss and optic nerve atrophy. Elevated intraocular pressure (IOP) is a main risk factor for onset and progression of the disease. Since increased IOP is the only modifiable risk factor, relevant models for glaucoma would comprise RGC and optic nerve damage triggered by ocular hypertension. Animal models of glaucoma have greatly contributed to the understanding of the molecular mechanisms of this pathology, and they have also facilitated the development of new pharmacological interventions. Although animal models of glaucoma have provided valuable information about the disease, there is still no ideal model for studying glaucoma due to its complexity. There is a recognized demand for in vitro models that can replace or reduce the need for animal experiments. Several in vitro models have emerged as a great opportunity in the field of glaucoma research, helping to clarify the mechanisms involved in disease progression. Several types of equipment have been developed to expose cells and tissue cultures to elevated pressures. Herein, we discuss the methodology used to increase pressure, the main findings, and the relevance of in vitro models for the study of the pathophysiology of glaucoma.

  18. AN EVALUATION MODEL FOR PRIMARY VISUAL ARTS LESSON

    Directory of Open Access Journals (Sweden)

    Yüksel GÖĞEBAKAN

    2012-06-01

    Full Text Available This study was done to determine the evaluation criteria to be used in a clay tablet production activity in visual arts lesson. In the study, the gains within the learning domains of museum awareness and formation in visual arts as specified in primary visual arts lesson curriculum were associated with the common gains specified within Science, Technology and Society learning domain. The study was conducted on 64 students selected randomly from among the 7th graders in Atatürk Primary School in Malatya province. As a part of the study, a trip to the Malatya Archeology Museum was arranged as required by the lesson plan prepared in line with the common gains of both lessons. Several activities were performed during this trip. One of the activities was a genuine tablet production activity based on a tablet in the museum. The main purpose of the present study is to decide what criteria to use to evaluate the tablets produced by the students in the visual arts lesson.

  19. Observational modeling of topological spaces

    Energy Technology Data Exchange (ETDEWEB)

    Molaei, M.R. [Department of Mathematics, Shahid Bahonar University of Kerman, Kerman 76169-14111 (Iran, Islamic Republic of)], E-mail: mrmolaei@mail.uk.ac.ir

    2009-10-15

    In this paper a model for a multi-dimensional observer by using of the fuzzy theory is presented. Relative form of Tychonoff theorem is proved. The notion of topological entropy is extended. The persistence of relative topological entropy under relative conjugate relation is proved.

  20. Lessons from model organisms: phenotypic robustness and missing heritability in complex disease.

    Directory of Open Access Journals (Sweden)

    Christine Queitsch

    Full Text Available Genetically tractable model organisms from phages to mice have taught us invaluable lessons about fundamental biological processes and disease-causing mutations. Owing to technological and computational advances, human biology and the causes of human diseases have become accessible as never before. Progress in identifying genetic determinants for human diseases has been most remarkable for Mendelian traits. In contrast, identifying genetic determinants for complex diseases such as diabetes, cancer, and cardiovascular and neurological diseases has remained challenging, despite the fact that these diseases cluster in families. Hundreds of variants associated with complex diseases have been found in genome-wide association studies (GWAS, yet most of these variants explain only a modest amount of the observed heritability, a phenomenon known as "missing heritability." The missing heritability has been attributed to many factors, mainly inadequacies in genotyping and phenotyping. We argue that lessons learned about complex traits in model organisms offer an alternative explanation for missing heritability in humans. In diverse model organisms, phenotypic robustness differs among individuals, and those with decreased robustness show increased penetrance of mutations and express previously cryptic genetic variation. We propose that phenotypic robustness also differs among humans and that individuals with lower robustness will be more responsive to genetic and environmental perturbations and hence susceptible to disease. Phenotypic robustness is a quantitative trait that can be accurately measured in model organisms, but not as yet in humans. We propose feasible approaches to measure robustness in large human populations, proof-of-principle experiments for robustness markers in model organisms, and a new GWAS design that takes differences in robustness into account.

  1. What causes type 1 diabetes? Lessons from animal models.

    Science.gov (United States)

    Buschard, Karsten

    2011-07-01

    concert. Neutralization of any one of these factors is capable of stopping T1D development, as lessons are learned from the animal models.

  2. Developing a PLC-friendly state machine model: lessons learned

    Science.gov (United States)

    Pessemier, Wim; Deconinck, Geert; Raskin, Gert; Saey, Philippe; Van Winckel, Hans

    2014-07-01

    Modern Programmable Logic Controllers (PLCs) have become an attractive platform for controlling real-time aspects of astronomical telescopes and instruments due to their increased versatility, performance and standardization. Likewise, vendor-neutral middleware technologies such as OPC Unified Architecture (OPC UA) have recently demonstrated that they can greatly facilitate the integration of these industrial platforms into the overall control system. Many practical questions arise, however, when building multi-tiered control systems that consist of PLCs for low level control, and conventional software and platforms for higher level control. How should the PLC software be structured, so that it can rely on well-known programming paradigms on the one hand, and be mapped to a well-organized OPC UA interface on the other hand? Which programming languages of the IEC 61131-3 standard closely match the problem domains of the abstraction levels within this structure? How can the recent additions to the standard (such as the support for namespaces and object-oriented extensions) facilitate a model based development approach? To what degree can our applications already take advantage of the more advanced parts of the OPC UA standard, such as the high expressiveness of the semantic modeling language that it defines, or the support for events, aggregation of data, automatic discovery, ... ? What are the timing and concurrency problems to be expected for the higher level tiers of the control system due to the cyclic execution of control and communication tasks by the PLCs? We try to answer these questions by demonstrating a semantic state machine model that can readily be implemented using IEC 61131 and OPC UA. One that does not aim to capture all possible states of a system, but rather one that attempts to organize the course-grained structure and behaviour of a system. In this paper we focus on the intricacies of this seemingly simple task, and on the lessons that we

  3. Lesson Study Model: The Challenge of Transforming a Global Idea into Local Practice

    Science.gov (United States)

    Grimsaeth, Gerd; Hallås, Bjørg Oddrun

    2016-01-01

    The lesson study (LS) model, which originated in Japan, has become popular all over the world. This article will highlight some of the challenges encountered when the LS model was picked up and introduced in a local school context in a Norwegian municipality. The article views this process in the light of research on LS-model transfer into local…

  4. Transitioning from a U.N. Observer Mission to a Robust Peacekeeping Operation: Lessons from Sierra Leone

    Science.gov (United States)

    2007-11-02

    U.N.CHAPTER VI OBSERVER MISSION TO A ROBUST PEACEKEEPING OPERATION: LESSONS FROM SIERRA LEONE 9. Personal Authors: Peter V. Londono, CIV 10.Type of...necessarily endorsed by the NWC or the Department of the Navy. 14. Ten key words that relate to your paper: Peacekeeping, U.N., Sierra Leone , UNOMSIL...UNAMSIL, RUF, Peace Enforcement, Operation Relief Focus, ECOWAS, ECOMOG 15.Abstract: U.N. peacekeeping operations in Sierra Leone have special

  5. A new approach to managing Lessons Learned in PMBoK process groups: the Ballistic 2.0 Model

    Directory of Open Access Journals (Sweden)

    Marcirio Chaves

    2016-01-01

    Full Text Available In any organization, dealing with lessons learned is a complex issue that involves people, processes and technologies. Although lessons learned processes are already well established in the project management community, the use of modern web technologies to support them is still in its infancy. This paper introduces a new model to manage lessons learned in PMBoK process groups. This model draws upon interdisciplinary literature, which embeds lessons learned processes, shared context and Web 2.0 service models. The model is supported by Web 2.0 technologies and centered in PMBoK process groups to allow a thorough overview of the project. An exploratory focus group was set up to validate the model qualitatively within a constructivist ontology and an interpretive epistemology. The adoption of this model can help academics and practitioners using PMBoK process groups to acquire a better understanding of managing lessons learned in projects.

  6. Characterizing Cold Giant Planets in Reflected Light: Lessons from 50 Years of Outer Solar System Exploration and Observation

    Science.gov (United States)

    Marley, Mark Scott; Hammel, Heidi

    2014-01-01

    A space based coronagraph, whether as part of the WFIRST/AFTA mission or on a dedicated space telescope such as Exo-C or -S, will be able to obtain photometry and spectra of multiple gas giant planets around nearby stars, including many known from radial velocity detections. Such observations will constrain the masses, atmospheric compositions, clouds, and photochemistry of these worlds. Giant planet albedo models, such as those of Cahoy et al. (2010) and Lewis et al. (this meeting), will be crucial for mission planning and interpreting the data. However it is equally important that insights gleaned from decades of solar system imaging and spectroscopy of giant planets be leveraged to optimize both instrument design and data interpretation. To illustrate these points we will draw on examples from solar system observations, by both HST and ground based telescopes, as well as by Voyager, Galileo, and Cassini, to demonstrate the importance clouds, photochemical hazes, and various molecular absorbers play in sculpting the light scattered by solar system giant planets. We will demonstrate how measurements of the relative depths of multiple methane absorption bands of varying strengths have been key to disentangling the competing effects of gas column abundances, variations in cloud height and opacity, and scattering by high altitude photochemical hazes. We will highlight both the successes, such as the accurate remote determination of the atmospheric methane abundance of Jupiter, and a few failures from these types of observations. These lessons provide insights into technical issues facing spacecraft designers, from the selection of the most valuable camera filters to carry to the required capabilities of the flight spectrometer, as well as mission design questions such as choosing the most favorable phase angles for atmospheric characterization.

  7. Literacy Models and the Reconstruction of History Education: A Comparative Discourse Analysis of Two Lesson Plans

    Science.gov (United States)

    Collin, Ross; Reich, Gabriel A.

    2015-01-01

    This article presents discourse analyses of two lesson plans designed for secondary school history classes. Although the plans focus on the same topic, they rely on different models of content area literacy: disciplinary literacy, or reading and writing like experts in a given domain, and critical literacy, or reading and writing to address…

  8. Literacy Models and the Reconstruction of History Education: A Comparative Discourse Analysis of Two Lesson Plans

    Science.gov (United States)

    Collin, Ross; Reich, Gabriel A.

    2015-01-01

    This article presents discourse analyses of two lesson plans designed for secondary school history classes. Although the plans focus on the same topic, they rely on different models of content area literacy: disciplinary literacy, or reading and writing like experts in a given domain, and critical literacy, or reading and writing to address…

  9. Rotation in liquid $^{4}He$ Lessons from a toy model

    CERN Document Server

    Lehmann, K K

    2000-01-01

    This paper presents an analysis of a model problem, consisting of two interacting rigid rings, for the rotation of molecules in liquid $^4$He. Due to Bose symmetry, the excitation of the rotor corresponding to a ring of N helium atoms is restricted to states with integer multiples of N quanta of angular momentum. This minimal model shares many of the same features of the rotational spectra that have been observed for molecules in nanodroplets of $\\approx 10^3 - 10^4$ helium atoms. In particular, this model predicts, for the first time, the very large enhancement of the centrifugal distortion constants that have been observed experimentally. It also illustrates the different effects of increasing rotational velocity by increases in angular momentum quantum number or by increasing the rotational constant of the molecular rotor. It is found that fixed node, diffusion Monte Carlo and a hydrodynamic model provide upper and lower bounds on the size of the effective rotational constant of the molecular rotor when co...

  10. Model Observers in Medical Imaging Research

    OpenAIRE

    He, Xin; Park, Subok

    2013-01-01

    Model observers play an important role in the optimization and assessment of imaging devices. In this review paper, we first discuss the basic concepts of model observers, which include the mathematical foundations and psychophysical considerations in designing both optimal observers for optimizing imaging systems and anthropomorphic observers for modeling human observers. Second, we survey a few state-of-the-art computational techniques for estimating model observers and the principles of im...

  11. Selection bias in evaluating of influenza vaccine effectiveness: a lesson from an observational study of elderly nursing home residents.

    Science.gov (United States)

    Fukushima, Wakaba; Hayashi, Yoshimitsu; Mizuno, Yaichi; Suzuki, Kanzo; Kase, Tetsuo; Ohfuji, Satoko; Fujieda, Megumi; Maeda, Akiko; Hirota, Yoshio

    2008-11-25

    Selection bias is of critical concern in the study of influenza vaccine effectiveness when using an observational study design. This bias is attributable to the inherently different characteristics between vaccinees and non-vaccinees. The differences, which are related both to vaccination and signs of clinical disease as an outcome, may lead to erroneous estimation of the effectiveness. In this report, we describe how selection bias among elderly nursing home residents may lead to a spurious interpretation of the protective effect of influenza vaccine. Our results should be a lesson in the importance of regarding selection bias when assessing influenza vaccine effectiveness.

  12. Modeling and public health emergency responses: lessons from SARS.

    Science.gov (United States)

    Glasser, John W; Hupert, Nathaniel; McCauley, Mary M; Hatchett, Richard

    2011-03-01

    Modelers published thoughtful articles after the 2003 SARS crisis, but had limited if any real-time impact on the global response and may even have inadvertently contributed to a lingering misunderstanding of the means by which the epidemic was controlled. The impact of any intervention depends on its efficiency as well as efficacy, and efficient isolation of infected individuals before they become symptomatic is difficult to imagine. Nonetheless, in exploring the possible impact of quarantine, the product of efficiency and efficacy was varied over the entire unit interval. Another mistake was repeatedly fitting otherwise appropriate gamma distributions to times to event regardless of whether they were stationary or not, particularly onset-isolation intervals whose progressive reduction evidently contributed to SARS control. By virtue of their unknown biology, newly-emerging diseases are more challenging than familiar human scourges. Influenza, for example, recurs annually and has been modeled more thoroughly than any other infectious disease. Moreover, models were integrated into preparedness exercises, during which working relationships were established that bore fruit during the 2009 A/H1N1 pandemic. To provide the most accurate and timely advice possible, especially about the possible impact of measures designed to control diseases caused by novel human pathogens, we must appreciate the value and difficulty of policy-oriented modeling. Effective communication of insights gleaned from modeling SARS will help to ensure that policymakers involve modelers in future outbreaks of newly-emerging infectious diseases. Accordingly, we illustrate the increasingly timely care-seeking by which, together with increasingly accurate diagnoses and effective isolation, SARS was controlled via heuristic arguments and descriptive analyses of familiar observations.

  13. Model observers in medical imaging research.

    Science.gov (United States)

    He, Xin; Park, Subok

    2013-10-04

    Model observers play an important role in the optimization and assessment of imaging devices. In this review paper, we first discuss the basic concepts of model observers, which include the mathematical foundations and psychophysical considerations in designing both optimal observers for optimizing imaging systems and anthropomorphic observers for modeling human observers. Second, we survey a few state-of-the-art computational techniques for estimating model observers and the principles of implementing these techniques. Finally, we review a few applications of model observers in medical imaging research.

  14. Detection and plant monitoring programs: lessons from an intensive survey of Asclepias meadii with five observers.

    Science.gov (United States)

    Alexander, Helen M; Reed, Aaron W; Kettle, W Dean; Slade, Norman A; Bodbyl Roels, Sarah A; Collins, Cathy D; Salisbury, Vaughn

    2012-01-01

    Monitoring programs, where numbers of individuals are followed through time, are central to conservation. Although incomplete detection is expected with wildlife surveys, this topic is rarely considered with plants. However, if plants are missed in surveys, raw count data can lead to biased estimates of population abundance and vital rates. To illustrate, we had five independent observers survey patches of the rare plant Asclepias meadii at two prairie sites. We analyzed data with two mark-recapture approaches. Using the program CAPTURE, the estimated number of patches equaled the detected number for a burned site, but exceeded detected numbers by 28% for an unburned site. Analyses of detected patches using Huggins models revealed important effects of observer, patch state (flowering/nonflowering), and patch size (number of stems) on probabilities of detection. Although some results were expected (i.e. greater detection of flowering than nonflowering patches), the importance of our approach is the ability to quantify the magnitude of detection problems. We also evaluated the degree to which increased observer numbers improved detection: smaller groups (3-4 observers) generally found 90 - 99% of the patches found by all five people, but pairs of observers or single observers had high error and detection depended on which individuals were involved. We conclude that an intensive study at the start of a long-term monitoring study provides essential information about probabilities of detection and what factors cause plants to be missed. This information can guide development of monitoring programs.

  15. Experiences in Applying Earth Observing Satellite Technology in SERVIR Regions with an Emphasis on Disasters: Successes, Lessons and Paths Forward

    Science.gov (United States)

    Anderson, Eric

    2017-01-01

    Earth observing satellites offer a unique perspective of our environment from the vantage point of space. Repeated measurements of the Earths subsystems such as the biosphere, atmosphere, lithosphere, hydrosphere, and of humans interactions with their environments, allow for a better understanding of Earth system processes, and they can provide input for decision making in areas of environmental management and disaster risk reduction. SERVIR is a joint initiative of the US National Aeronautics and Space Administration (NASA) and the US Agency for International Development (USAID) that began in 2005 and has been active in applying Earth observations for sustainable development in many regions around the world, recently the Lower Mekong and West Africa regions. This talk will highlight some successes achieved and lessons learned through SERVIR in Central America, Eastern Southern Africa, and the Hindu Kush-Himalaya region, focusing on disasters. We will also present opportunities for enhanced decision making with Earth observations and geospatial technologies in the Lower Mekong region.

  16. Comparison between observations and model

    OpenAIRE

    Claußnitzer, Antje

    2010-01-01

    In recent years the development of numerical weather prediction models has shown great progress in the short-term and medium-range forecast of temperature, wind speed or direction and cloud coverage, but only little success in the quantitative precipitation forecast. Rainfall is one of the most difficult forecasting meteorological variable. To improve the numerical models, it is necessary to understand the rainfall processes. This thesis contributes towards an understanding since the precipit...

  17. The Beginnings of Civilization in the Near East and Africa: Mesopotamia, Egypt, and Kush. Grade 6 Model Lesson for Unit II. California History-Social Science Course Models.

    Science.gov (United States)

    Zachlod, Michelle, Ed.

    This model lesson for sixth graders about the beginnings of civilization in the Near East and Africa aims to have students focus on the cultural and geographical features of a region: landforms, climate, and vegetation. The lesson features three major topics: (1) Sumer and Mesopotamia, (2) Egypt, and (3) Kush. It addresses the uses and…

  18. The Beginnings of Civilization in the Near East and Africa: Mesopotamia, Egypt, and Kush. Grade 6 Model Lesson for Unit II. California History-Social Science Course Models.

    Science.gov (United States)

    Zachlod, Michelle, Ed.

    This model lesson for sixth graders about the beginnings of civilization in the Near East and Africa aims to have students focus on the cultural and geographical features of a region: landforms, climate, and vegetation. The lesson features three major topics: (1) Sumer and Mesopotamia, (2) Egypt, and (3) Kush. It addresses the uses and…

  19. Lessons in Nonhuman Primate Models for AIDS Vaccine Research: From Minefields to Milestones

    OpenAIRE

    Jeffrey D Lifson; Nancy L Haigwood

    2012-01-01

    Nonhuman primate (NHP) disease models for AIDS have made important contributions to the search for effective vaccines for AIDS. Viral diversity, persistence, capacity for immune evasion, and safety considerations have limited development of conventional approaches using killed or attenuated vaccines, necessitating the development of novel approaches. Here we highlight the knowledge gained and lessons learned in testing vaccine concepts in different virus/NHP host combinations.

  20. Measles immune suppression: lessons from the macaque model.

    Directory of Open Access Journals (Sweden)

    Rory D de Vries

    Full Text Available Measles remains a significant childhood disease, and is associated with a transient immune suppression. Paradoxically, measles virus (MV infection also induces robust MV-specific immune responses. Current hypotheses for the mechanism underlying measles immune suppression focus on functional impairment of lymphocytes or antigen-presenting cells, caused by infection with or exposure to MV. We have generated stable recombinant MVs that express enhanced green fluorescent protein, and remain virulent in non-human primates. By performing a comprehensive study of virological, immunological, hematological and histopathological observations made in animals euthanized at different time points after MV infection, we developed a model explaining measles immune suppression which fits with the "measles paradox". Here we show that MV preferentially infects CD45RA(- memory T-lymphocytes and follicular B-lymphocytes, resulting in high infection levels in these populations. After the peak of viremia MV-infected lymphocytes were cleared within days, followed by immune activation and lymph node enlargement. During this period tuberculin-specific T-lymphocyte responses disappeared, whilst strong MV-specific T-lymphocyte responses emerged. Histopathological analysis of lymphoid tissues showed lymphocyte depletion in the B- and T-cell areas in the absence of apoptotic cells, paralleled by infiltration of T-lymphocytes into B-cell follicles and reappearance of proliferating cells. Our findings indicate an immune-mediated clearance of MV-infected CD45RA(- memory T-lymphocytes and follicular B-lymphocytes, which causes temporary immunological amnesia. The rapid oligoclonal expansion of MV-specific lymphocytes and bystander cells masks this depletion, explaining the short duration of measles lymphopenia yet long duration of immune suppression.

  1. Aviation Safety Risk Modeling: Lessons Learned From Multiple Knowledge Elicitation Sessions

    Science.gov (United States)

    Luxhoj, J. T.; Ancel, E.; Green, L. L.; Shih, A. T.; Jones, S. M.; Reveley, M. S.

    2014-01-01

    Aviation safety risk modeling has elements of both art and science. In a complex domain, such as the National Airspace System (NAS), it is essential that knowledge elicitation (KE) sessions with domain experts be performed to facilitate the making of plausible inferences about the possible impacts of future technologies and procedures. This study discusses lessons learned throughout the multiple KE sessions held with domain experts to construct probabilistic safety risk models for a Loss of Control Accident Framework (LOCAF), FLightdeck Automation Problems (FLAP), and Runway Incursion (RI) mishap scenarios. The intent of these safety risk models is to support a portfolio analysis of NASA's Aviation Safety Program (AvSP). These models use the flexible, probabilistic approach of Bayesian Belief Networks (BBNs) and influence diagrams to model the complex interactions of aviation system risk factors. Each KE session had a different set of experts with diverse expertise, such as pilot, air traffic controller, certification, and/or human factors knowledge that was elicited to construct a composite, systems-level risk model. There were numerous "lessons learned" from these KE sessions that deal with behavioral aggregation, conditional probability modeling, object-oriented construction, interpretation of the safety risk results, and model verification/validation that are presented in this paper.

  2. Managing business model innovation risks - lessons for theory and practice

    DEFF Research Database (Denmark)

    Taran, Yariv; Chester Goduscheit, René; Boer, Harry

    2015-01-01

    This paper focuses on the challenges related to, and the risk management needed in, the process of business model innovation. Business model innovation may involve hefty investments, high levels of uncertainty, complexity and, inevitably, risk. Although many firms follow a first mover strategic...... approach, arguing from a “no risk no reward” aphorism, a sloppy implementation approach towards business model innovation may result in catastrophic, sometimes even fatal, consequences to a firm’s core business. Based on four unsuccessful business model innovation experiences, which took place in three...... industrial firms, we discuss the reasons that led to these failures, and outline various possible solutions for practitioners to manage business model innovation adequately....

  3. Model Pembelajaran Seni Musik melalui Lesson Study: Studi Kasus di SDN Jawilan, Serang

    Directory of Open Access Journals (Sweden)

    Yulianti Fitriani

    2015-03-01

    Full Text Available Artikel ini dilatar-belakangi persoalan pembelajaran seni musik di SDN Jawilan Kab. Serang. Di SD ini penyelenggaraan pendidikan seni belum memperoleh perhatian yang cukup baik dari guru. Hal ini dapat dilihat dari pembagian alokasi waktu pembelajaran dan keterlibatan guru kelas yang tidak memiliki latar belakang pendidikan seni (musik. Dampak yang muncul, rata-rata siswa belum memiliki kemandirian dalam berkreativitas dan kurang berpartisipasi aktif dalam kegiatan musik baik di sekolah maupun di luar sekolah. Untuk memperbaiki persoalan tersebut dirasa perlu meminjam Lesson Study yang di dalamnya terdapat metode, pendekatan dan strategi pembelajaran sebagai pola untuk membelajarkan seni musik agar dapat memberikan alternatif sudut pandang terhadap persoalan metode yang tepat guna dan terencana dalam pengajaran pendidikan musik di SD, termasuk paradigma membelajarkan musik secara hakiki. Hasil yang diperoleh dapat memberikan alternatif sebagai dasar pengembangan pembelajaran seni musik.   The Model of Music Learning through a Lesson Study: A Case Study in Jawilan Elementary School, Serang. The learning problems of music lessons at Jawilan Elementary School in Serang becomes the mainly source of the research background in this article. The implementation of art education in this school has not gained enough attention from teachers. It can be seen from the distribution of the allocated time of learning and the involvement of classroom teachers who do not have sufficient background in art education (music. The appearing impact shows that the average of students do not have any independence in creativity and have less-active participation in the activities of musical arts either in school or outside the school. However, solving the problem is necessary to do by using a Lesson Study as a pattern (approaches, strategies, and methods of learning to teach music that can be used as an alternative point of view in developing methods and organizing the

  4. Immunology of fungal infections: lessons learned from animal models.

    Science.gov (United States)

    Steele, Chad; Wormley, Floyd L

    2012-08-01

    The continuing AIDS epidemic coupled with increased usage of immunosuppressive drugs to prevent organ rejection or treat autoimmune diseases has resulted in an increase in individuals at risk for acquiring fungal diseases. These concerns highlight the need to elucidate mechanisms of inducing protective immune responses against fungal pathogens. Consequently, several experimental models of human mycoses have been developed to study these diseases. The availability of transgenic animal models allows for in-depth analysis of specific components, receptors, and signaling pathways that elicit protection against fungal diseases. This review focuses on recent advances in our understanding of immune responses to fungal infections gained using animal models.

  5. Innate immunity against moulds: lessons learned from invertebrate models.

    Science.gov (United States)

    Ben-Ami, Ronen

    2011-01-01

    The emergence over the past two decades of invasive mycoses as a significant problem in immunocompromised patients underscores the importance of deciphering innate immunity against filamentous fungi. However, the complexity and cost of traditionally used mammalian model hosts presents a bottleneck that has limited the rate of advances in this field. In contrast, invertebrate model hosts have several important advantages, including simple immune systems, genetic tractability, and amenity to high-throughput experiments. The application of these models to studies of host-pathogen interactions is contingent on two tenets: (1) host innate defenses are preserved across widely disparate taxa, and (2) similar fungal virulence factors are operative in insects and in mammals. Validation of these principles paved the way for the use of invertebrates as facile models for studying invasive mould infections. These studies have helped shape our understanding of human pattern recognition receptors, phagocytic cell function and antimicrobial proteins, and their roles in host defense against filamentous fungi.

  6. Biology of Obesity: Lessons from Animal Models of Obesity

    Directory of Open Access Journals (Sweden)

    Keizo Kanasaki

    2011-01-01

    problems, including diabetes, cardiovascular disease, respiratory failure, muscle weakness, and cancer. The precise molecular mechanisms by which obesity induces these health problems are not yet clear. To better understand the pathomechanisms of human disease, good animal models are essential. In this paper, we will analyze animal models of obesity and their use in the research of obesity-associated human health conditions and diseases such as diabetes, cancer, and obstructive sleep apnea syndrome.

  7. Lessons Learned from Quantitative Dynamical Modeling in Systems Biology

    Science.gov (United States)

    Bachmann, Julie; Matteson, Andrew; Schelke, Max; Kaschek, Daniel; Hug, Sabine; Kreutz, Clemens; Harms, Brian D.; Theis, Fabian J.; Klingmüller, Ursula; Timmer, Jens

    2013-01-01

    Due to the high complexity of biological data it is difficult to disentangle cellular processes relying only on intuitive interpretation of measurements. A Systems Biology approach that combines quantitative experimental data with dynamic mathematical modeling promises to yield deeper insights into these processes. Nevertheless, with growing complexity and increasing amount of quantitative experimental data, building realistic and reliable mathematical models can become a challenging task: the quality of experimental data has to be assessed objectively, unknown model parameters need to be estimated from the experimental data, and numerical calculations need to be precise and efficient. Here, we discuss, compare and characterize the performance of computational methods throughout the process of quantitative dynamic modeling using two previously established examples, for which quantitative, dose- and time-resolved experimental data are available. In particular, we present an approach that allows to determine the quality of experimental data in an efficient, objective and automated manner. Using this approach data generated by different measurement techniques and even in single replicates can be reliably used for mathematical modeling. For the estimation of unknown model parameters, the performance of different optimization algorithms was compared systematically. Our results show that deterministic derivative-based optimization employing the sensitivity equations in combination with a multi-start strategy based on latin hypercube sampling outperforms the other methods by orders of magnitude in accuracy and speed. Finally, we investigated transformations that yield a more efficient parameterization of the model and therefore lead to a further enhancement in optimization performance. We provide a freely available open source software package that implements the algorithms and examples compared here. PMID:24098642

  8. Lessons learned from quantitative dynamical modeling in systems biology.

    Directory of Open Access Journals (Sweden)

    Andreas Raue

    Full Text Available Due to the high complexity of biological data it is difficult to disentangle cellular processes relying only on intuitive interpretation of measurements. A Systems Biology approach that combines quantitative experimental data with dynamic mathematical modeling promises to yield deeper insights into these processes. Nevertheless, with growing complexity and increasing amount of quantitative experimental data, building realistic and reliable mathematical models can become a challenging task: the quality of experimental data has to be assessed objectively, unknown model parameters need to be estimated from the experimental data, and numerical calculations need to be precise and efficient. Here, we discuss, compare and characterize the performance of computational methods throughout the process of quantitative dynamic modeling using two previously established examples, for which quantitative, dose- and time-resolved experimental data are available. In particular, we present an approach that allows to determine the quality of experimental data in an efficient, objective and automated manner. Using this approach data generated by different measurement techniques and even in single replicates can be reliably used for mathematical modeling. For the estimation of unknown model parameters, the performance of different optimization algorithms was compared systematically. Our results show that deterministic derivative-based optimization employing the sensitivity equations in combination with a multi-start strategy based on latin hypercube sampling outperforms the other methods by orders of magnitude in accuracy and speed. Finally, we investigated transformations that yield a more efficient parameterization of the model and therefore lead to a further enhancement in optimization performance. We provide a freely available open source software package that implements the algorithms and examples compared here.

  9. Plant lessons: exploring ABCB functionality through structural modeling

    Directory of Open Access Journals (Sweden)

    Aurélien eBailly

    2012-01-01

    Full Text Available In contrast to mammalian ABCB1 proteins, narrow substrate specificity has been extensively documented for plant orthologs shown to catalyze the transport of the plant hormone, auxin. Using the crystal structures of the multidrug exporters Sav1866 and MmABCB1 as templates, we have developed structural models of plant ABCB proteins with a common architecture. Comparisons of these structures identified kingdom-specific candidate substrate-binding regions within the translocation chamber formed by the transmembrane domains of ABCBs from the model plant Arabidopsis. These results suggest an early evolutionary divergence of plant and mammalian ABCBs. Validation of these models becomes a priority for efforts to elucidate ABCB function and manipulate this class of transporters to enhance plant productivity and quality.

  10. Molecular bases of myelodysplastic syndromes: lessons from animal models.

    Science.gov (United States)

    Komeno, Yukiko; Kitaura, Jiro; Kitamura, Toshio

    2009-06-01

    Myelodysplastic syndrome (MDS) is a clonal disorder of hematopietic stem cells characterized by ineffective hematopoiesis, peripheral blood cytopenia, morphologic dysplasia, and susceptibility to acute myeloid leukemia. Several mechanisms have been suggested as causes of MDS: unbalanced chromosomal abnormalities reflecting a gain or loss of chromosomal material, point mutations of transcription factors, and inactivation of p53. However, appropriate animal models that mimic MDS have long been lacking. We recently reported a novel murine model of MDS that recapitulates trilineage dysplasia and transformation to AML. In this review, we summarize the animal models of MDS and discuss the molecular bases of MDS as well as those of leukemia and myeloproliferative disorders (MPD). J. Cell. Physiol. 219: 529-534, 2009. (c) 2009 Wiley-Liss, Inc.

  11. The Cohort Model: Lessons Learned When Principals Collaborate

    Science.gov (United States)

    Umekubo, Lisa A.; Chrispeels, Janet H.; Daly, Alan J.

    2015-01-01

    This study explored a formal structure, the cohort model that a decentralized district put in place over a decade ago. Schools were clustered into cohorts to facilitate professional development for leadership teams for all 44 schools within the district. Drawing upon Senge's components of organizational learning, we used a single case study design…

  12. Lessons Learned Model Checking an Industrial Communications Library

    Science.gov (United States)

    2005-09-01

    Lecture Notes in Computer Science [LNCS], volume 2057). Toronto, Canada, May 19-20, 2001. Berlin...Model Checking,” 128-147. Integrated Formal Methods: The 4th International Conference (IFM 2004) ( Lecture Notes in Computer Science [LNCS], volume...on Computer Aided Verification (CAV 1990). ( Lecture Notes in Computer Science [LNCS], volume 531). New Brunswick, NJ, June 18-21, 1990.

  13. PENGEMBANGAN PERANGKAT DAN MODEL PEMBELAJARAN BERBASIS KONSTRUKTIVIS MATAKULIAH STATISTIKA MELALUI PENDEKATAN LESSON STUDY

    Directory of Open Access Journals (Sweden)

    Nining Setyaningsih

    2015-07-01

    Full Text Available This research aims to produce instructional design and model-based constructivist learning course of Statistics Math through lesson study in an effort to improve the quality of learning. Besides, it is also to find the effect of the use of the device and the constructivist model of learning based on student results. This study uses the approach of research and development (research & development. Results of research and development are as follows: (1 The statistical learning mathematics, covering the syllabus, lecture and Quality Plans, and Teaching materials are ready to be validated through lesson study approach, planning, implementation, reflection, and follow-up. (2 Design-based constructivist learning model includes the stages of orientation, elicitasi, restructuring ideas, the application and review. (3 Based on the findings of the trial results and the model of learning, particularly in the development of student activity indicates that the use of constructivist-based learning model can increase the activity of students, as measured by indicators of the ability to answer questions, the ability to propose ideas, and the ability to submit allegations.

  14. Implementation of Software Configuration Management Process by Models: Practical Experiments and Learned Lessons

    Directory of Open Access Journals (Sweden)

    Bartusevics Arturs

    2014-12-01

    Full Text Available Nowadays software configuration management process is not only dilemma which system should be used for version control or how to merge changes from one source code branch to other. There are multiple tasks such as version control, build management, deploy management, status accounting, bug tracking and many others that should be solved to support full configuration management process according to most popular quality standards. The main scope of the mentioned process is to include only valid and tested software items to final version of product and prepare a new version as soon as possible. To implement different tasks of software configuration management process, a set of different tools, scripts and utilities should be used. The current paper provides a new model-based approach to implementation of configuration management. Using different models, a new approach helps to organize existing solutions and develop new ones by a parameterized way, thus increasing reuse of solutions. The study provides a general description of new model-based conception and definitions of all models needed to implement a new approach. The second part of the paper contains an overview of criteria, practical experiments and lessons learned from using new models in software configuration management. Finally, further works are defined based on results of practical experiments and lessons learned.

  15. Project-Based Learning Using Discussion and Lesson-Learned Methods via Social Media Model for Enhancing Problem Solving Skills

    Science.gov (United States)

    Jewpanich, Chaiwat; Piriyasurawong, Pallop

    2015-01-01

    This research aims to 1) develop the project-based learning using discussion and lesson-learned methods via social media model (PBL-DLL SoMe Model) used for enhancing problem solving skills of undergraduate in education student, and 2) evaluate the PBL-DLL SoMe Model used for enhancing problem solving skills of undergraduate in education student.…

  16. Business Model Design: Lessons Learned from Tesla Motors

    OpenAIRE

    Chen, Yurong; Perez, Yannick

    2015-01-01

    International audience; Electric vehicle (EV) industry is still in the introduction stage in product life cycle, and its dominant design is still dormant. EV manufacturing companies have long taken numerous endeavors to promote EV in the niche markets by providing innovative business models. While most OEMs still take 'business as usual' approach for developing their EV production and offers, Tesla Motors, an EV entrepreneurial firm, stands out by providing disruptive innovation choices and s...

  17. STRESS INDUCED OBESITY: LESSONS FROM RODENT MODELS OF STRESS

    Directory of Open Access Journals (Sweden)

    Zachary Robert Patterson

    2013-07-01

    Full Text Available Stress is defined as the behavioral and physiological responses generated in the face of, or in anticipation of, a perceived threat. The stress response involves activation of the sympathetic nervous system and recruitment of the hypothalamic-pituitary-adrenal (HPA axis. When an organism encounters a stressor (social, physical, etc., these endogenous stress systems are stimulated in order to generate a fight-or-flight response, and manage the stressful situation. As such, an organism is forced to liberate energy resources in attempt to meet the energetic demands posed by the stressor. A change in the energy homeostatic balance is thus required to exploit an appropriate resource and deliver useable energy to the target muscles and tissues involved in the stress response. Acutely, this change in energy homeostasis and the liberation of energy is considered advantageous, as it is required for the survival of the organism. However, when an organism is subjected to a prolonged stressor, as is the case during chronic stress, a continuous irregularity in energy homeostasis is considered detrimental and may lead to the development of metabolic disturbances such as cardiovascular disease, type II diabetes mellitus and obesity. This concept has been studied extensively using animal models, and the neurobiological underpinnings of stress induced metabolic disorders are beginning to surface. However, different animal models of stress continue to produce divergent metabolic phenotypes wherein some animals become anorexic and loose body mass while others increase food intake and body mass and become vulnerable to the development of metabolic disturbances. It remains unclear exactly what factors associated with stress models can be used to predict the metabolic outcome of the organism. This review will explore a variety of rodent stress models and discuss the elements that influence the metabolic outcome in order to further our understanding of stress

  18. Lessons from the Current Japanese Triple Helix Model

    Directory of Open Access Journals (Sweden)

    Mitsuaki Hosono

    2012-12-01

    Full Text Available Since mid-1990s, the Japanese government has encouraged university-industry collaboration to foster innovations for economic growth. Learning from the American licensing model of technology transfer, Japanese Bay-Dole Act and TLO (Technology Licensing Organization Act were enacted in late 1990s. In addition, the corporatization of Japanese National Universities (JNUs in 2004 spurred their technology-transfer activities to obtain external funds. As a result, more than 50 TLOs has been established since FY1998, and also the number of patent application and licensed patents were increased at JUNs rapidly after FY2004. However, the licensing income has been stayed poor and some of TLOs were abolished. There are few evidences that the introduction of licensing model of technology transfer into Japan could contribute to innovation properly. Therefore, this study will try to clarify if licensing model of technology transfer work in Japan by analyzing the Japanese National University (JNU patent. There are 20,485 applied patent, which invented by JNU’s researcher(s from FY2004 to 2007. 38% of them were applied by solely by JNUs and 52% were by JNU and Private Firms etc. In the Japanese Patent Act, jointly applied patents are not licensed to the third party without the consent of co-applicant(s. Hence, more than half of the patent invented by JNU researchers is not basically used for patent licensing. Consequently, JNUs and TLOs face difficulties in patent licensing under the current Patent Act.

  19. Salmonella vaccines: lessons from the mouse model or bad teaching?

    Science.gov (United States)

    Strugnell, Richard A; Scott, Timothy A; Wang, Nancy; Yang, Chenying; Peres, Newton; Bedoui, Sammy; Kupz, Andreas

    2014-02-01

    Salmonella enterica subsp. enterica includes several very important human serovars including Typhi, Paratyphi, Typhimurium and Enteritidis. These bacteria cause a significant global burden of disease, typically classified into enteric fever, gastroenteritis and, more recently, invasive non-typhoidal salmonellosis (iNTS). Vaccines have been developed for one of these serovars, S. Typhi and the recent increase in iNTS cases has resulted in a push to develop new vaccines that will inhibit disease by S. Typhimurium and S. Enteritidis, the most common iNTS S. enterica serovars. The development of new human vaccines has been informed by studies in the murine model of typhoid fever based on S. Typhimurium infections of very 'sensitive' (Nramp-1(S)) mice, which has some obvious deficiencies, not the least that antibodies protect humans against S. Typhi infection but are only weakly protective in 'sensitive' mice infected with S. Typhimurium. S. Typhimurium also lacks Vi, the target of protective antibodies in typhoid fever. Notwithstanding these deficiencies, the murine model has identified a very complex series of innate and adaptive immune responses to infection that might be exploited to develop new vaccines. Equally, advances in understanding the pathogenesis of infection, through pathogenomics and more sophisticated animal models will likely contribute to the development of novel immunogens.

  20. Lessons learned from combined experimental and numerical modelling of urban floods

    Science.gov (United States)

    Archambeau, Pierre; Bruwier, Martin; Finaud-Guyot, Pascal; Erpicum, Sébastien; Pirotton, Michel; Dewals, Benjamin

    2017-04-01

    Field data for validating hydraulic models remain scarce. They are often limited to inundation extents and water marks, which provide little insights into the dynamic features of the flow in urbanized floodplains, such as the discharge partition in-between the streets and the velocity fields. To address this issue, a unique experimental setup representing a whole urban district was built in the laboratory ICube in Strasbourg and the state-of-the-art shallow-water model Wolf 2D was tested against the experimental measurements (Arrault et al. 2016). The numerical model was also used to extend and refine the analysis of the laboratory observations. The experimental model (5 m × 5 m) represents a square urban district with a total of 14 streets of different widths and 49 intersections (crossroads). The inflow discharge can be controlled in each street individually and the outflow discharges were measured downstream of each street. The numerical model Wolf was developed at the University of Liege and has been extensively used in flood risk research (Beckers et al. 2013, Bruwier et al. 2015, Detrembleur et al. 2015). Several lessons could be learned from this combined experimental and numerical analysis. First, we found that the discharge partition in-between the streets is primarily controlled by the street widths. Second, although the standard shallow-water equations reproduce satisfactorily most of the flow characteristics, adding a turbulence model improves the prediction of the shape and length of the flow recirculations in the streets. Yet, this has little influence on the discharge partition because the computed recirculation widths are hardly affected by the turbulence model. The experiments and the numerical model also show that the water depths in the streets remain fairly constant in-between two intersections, while they drop suddenly downstream of each intersection as a result of complex flow interactions at the intersections. This hints that friction has

  1. Lessons from the Current Japanese Triple Helix Model

    Directory of Open Access Journals (Sweden)

    Mitsuaki Hosono

    2013-01-01

    Full Text Available Since mid-1990s, the Japanese government has encouraged university-industry collaboration to foster innovations for economic growth. Learning from the American licensing model of technology transfer, Japanese Bay-Dole Act and TLO (Technology Licensing Organization Act were enacted in late 1990s. In addition, the corporatization of Japanese National Universities (JNUs in 2004 spurred their technology-transfer activities to obtain external funds. As a result, more than 50 TLOs has been established since FY1998, and also the number of patent application and licensed patents were increased at JUNs rapidly after FY2004. However, the licensing income has been stayed poor and some of TLOs were abolished. There are few evidences that the introduction of licensing model of technology transfer into Japan could contribute to innovation properly. Therefore, this study will try to clarify if licensing model of technology transfer work in Japan by analyzing the Japanese National University (JNU patent. There are 20,485 applied patent, which invented by JNU’s researcher(s from FY2004 to 2007. 38% of them were applied by solely by JNUs and 52% were by JNU and Private Firms etc. In the Japanese Patent Act, jointly applied patents are not licensed to the third party without the consent of co-applicant(s. Hence, more than half of the patent invented by JNU researchers is not basically used for patent licensing. Consequently, JNUs and TLOs face difficulties in patent licensing under the current Patent Act. Keywords: Technology Transfer, TLO, University Patent, Japan

  2. The tumor suppressor kinase LKB1: lessons from mouse models

    Institute of Scientific and Technical Information of China (English)

    Saara Ollila; Tomi P. M(a)kel(a)

    2011-01-01

    Mutations in the tumor suppressor gene LKB1 are important in hereditary Peutz-Jeghers syndrome,as well as in sporadic cancers including lung and cervical cancer.LKB1 is a kinase-activating Kinase,and a number of LKB1-dependent phosphorylation cascades regulate fundamental cellular and organismal processes in at least metabolism,polarity,cytoskeleton organization,and proliferation.Conditional targeting approaches are beginning to demonstrate the relevance and specificity of these signaling pathways in development and homeostasis of multiple organs.More than one of the pathways also appear to contribute to tumor growth following Lkb1 deficiencies based on a number of mouse tumor models.Lkb1-dependent activation of AMPK and subsequent inactivation of mammalian target of rapamycin signaling are implicated in several of the models,and other less well characterized pathways are also involved.Conditional targeting studies of Lkb1 also point an important role of LKB1 in epithelial-masenchymal interactions,significantly expanding knowledge on the relevance of LKB1 in human disease.

  3. Rethinking the causes of deforestation: lessons from economic models.

    Science.gov (United States)

    Angelsen, A; Kaimowitz, D

    1999-02-01

    Concern is rising over the deleterious effects of tropical deforestation. For example, the loss of forest cover influences the climate and reduces biodiversity, while reduced timber supplies, siltation, flooding, and soil degradation affect economic activity and threaten the livelihoods and cultural integrity of forest-dependent people. Such concerns have led economists to expand their efforts to model why, where, and to what extent forests are being converted to other land uses. This synthesis of the results of more than 140 economic models analyzing the causes of tropical deforestation brings into question many conventional hypotheses upon deforestation. More roads, higher agricultural prices, lower wages, and a shortage of off-farm employment generally lead to more deforestation. However, it is not known how technical change, agricultural input prices, household income levels, and tenure security affect deforestation. The role of macroeconomic factors such as population growth, poverty reduction, national income, economic growth, and foreign debt is also unclear. The authors nonetheless determine through their review that policy reforms included in current economic liberalization and adjustment efforts may increase pressure upon forests.

  4. Planning Lessons

    Institute of Scientific and Technical Information of China (English)

    Linda Jensen

    2007-01-01

    @@ Jensen's "Lesson Planning"article serves aS a guide fOr novice teachers who need to create formalized lesson plans.The article covers why,when,and how teachers plan lessons,as well aS basic lesson plan principles and a lesson plan template.

  5. Function of the hemochromatosis protein HFE: Lessons from animal models

    Institute of Scientific and Technical Information of China (English)

    Kostas Pantopoulos

    2008-01-01

    Hereditary hemochromatosis (HH) is caused by chronic hyperabsorption of dietary iron. Progressive accumulation of excess iron within tissue parenchymal cells may lead to severe organ damage. The most prevalent type of HH is linked to mutations in the HFE gene, encoding an atypical major histocompatibility complex class Ⅰ molecule. Shortly after its discovery in 1996, the hemochromatosis protein HFE was shown to physically interact with transferrin receptor 1 (TfR1)and impair the uptake of transferrin-bound iron in cells. However, these findings provided no clue why /-/FE mutations associate with systemic iron overload.It was later established that all forms of HH result from misregulation of hepcidin expression. This liverderived circulating peptide hormone controls iron efflux from duodenal enterocytes and reticuloendothelial macrophages by promoting the degradation of the iron exporter ferroportin. Recent studies with animal models of HH uncover a crucial role of HFE as a hepatocyte iron sensor and upstream regulator of helpcidin. Thus,hepatocyte HFE is indispensable for signaling to hepcidin, presumably as a constituent of a larger ironsensing complex. A working model postulates that the signaling activity of HFE is silenced when the protein is bound to TfR1. An increase in the iron saturation of plasma transferrin leads to displacement of TfR1 from HFE and assembly of the putative iron-sensing complex.In this way, iron uptake by the hepatocyte is translated into upregulation of hepcidin, reinforcing the concept that the liver is the major regulatory site for systemic iron homeostasis, and not merely an iron storage depot.

  6. Coronary revascularization in ischemic heart disease: lessons from observational studies and randomized clinical trials

    NARCIS (Netherlands)

    N.F. Mercado (Nestor)

    2003-01-01

    textabstractThis thesis presents an overview of clinical trials and observational studies on coronary revascularization and evaluates the results obtained with revascularization in different subsets of patients treated with percutaneous coronary intervention or coronary artery bypass graft surgery.

  7. Advancing an Information Model for Environmental Observations

    Science.gov (United States)

    Horsburgh, J. S.; Aufdenkampe, A. K.; Hooper, R. P.; Lehnert, K. A.; Schreuders, K.; Tarboton, D. G.; Valentine, D. W.; Zaslavsky, I.

    2011-12-01

    Observational data are fundamental to hydrology and water resources, and the way they are organized, described, and shared either enables or inhibits the analyses that can be performed using the data. The CUAHSI Hydrologic Information System (HIS) project is developing cyberinfrastructure to support hydrologic science by enabling better access to hydrologic data. HIS is composed of three major components. HydroServer is a software stack for publishing time series of hydrologic observations on the Internet as well as geospatial data using standards-based web feature, map, and coverage services. HydroCatalog is a centralized facility that catalogs the data contents of individual HydroServers and enables search across them. HydroDesktop is a client application that interacts with both HydroServer and HydroCatalog to discover, download, visualize, and analyze hydrologic observations published on one or more HydroServers. All three components of HIS are founded upon an information model for hydrologic observations at stationary points that specifies the entities, relationships, constraints, rules, and semantics of the observational data and that supports its data services. Within this information model, observations are described with ancillary information (metadata) about the observations to allow them to be unambiguously interpreted and used, and to provide traceable heritage from raw measurements to useable information. Physical implementations of this information model include the Observations Data Model (ODM) for storing hydrologic observations, Water Markup Language (WaterML) for encoding observations for transmittal over the Internet, the HydroCatalog metadata catalog database, and the HydroDesktop data cache database. The CUAHSI HIS and this information model have now been in use for several years, and have been deployed across many different academic institutions as well as across several national agency data repositories. Additionally, components of the HIS

  8. Rag defects and thymic stroma: lessons from animal models

    Directory of Open Access Journals (Sweden)

    Veronica eMarrella

    2014-06-01

    Full Text Available Thymocytes and thymic epithelial cells (TECs cross-talk is essential to support T-cell development and preserve thymic architecture and maturation of TECs and Foxp3+ natural regulatory T (nTreg cells. Accordingly, disruption of thymic lymphostromal cross-talk may have major implications on the thymic mechanisms that govern T cell tolerance. Several genetic defects have been described in humans that affect early stages of T cell development (leading to Severe Combined Immune Deficiency, SCID or late stages in thymocyte maturation (resulting in combined immunodeficiency. Hypomorphic mutations in SCID-causing genes may allow for generation of a limited pool of T lymphocytes with a restricted repertoire. These conditions are often associated with infiltration of peripheral tissues by activated T cells and immune dysregulation, as best exemplified by Omenn syndrome (OS. In this review, we will discuss our recent findings on abnormalities of thymic microenvironment in OS with a special focus of defective maturation of TECs, altered distribution of thymic dendritic cells (DCs and impairment of deletional and non-deletional mechanisms of central tolerance. Here, taking advantage of mouse models of OS and atypical SCID, we will discuss how modifications in stromal compartment impact and shape lymphocyte differentiation, and vice versa how inefficient T cell signalling results in defective stromal maturation. These findings are instrumental to understand the extent to which novel therapeutic strategies should act on thymic stroma to achieve full immune reconstitution.

  9. Pacific CRYSTAL Teacher Professional Development Models: Lessons Learned

    Science.gov (United States)

    van der Flier-Keller, E.; Yore, L.

    2010-12-01

    From 2005 to 2010 Pacific CRYSTAL (Centre for Research in Youth Science Teaching and Learning) has been engaged in community-based research fostering teacher leadership in innovative science education through a variety of approaches to teacher professional development. Pacific CRYSTAL is a University of Victoria based, NSERC funded project founded on a collaborative research model involving scentists, science educators and community members including schools, teachers, community groups and government. Pacific CRYSTAL professional development approaches embrace both in-service teachers and pre-service teachers, and include Lighthouse schools, workshops (ongoing as well as one-time), community-based partnerships in Pacific CRYSTAL research projects, teachers as researchers, and university science courses and workshops for pre-education and education students. A number of common themes, identified through these approaches, should be considered in the development and implementation of future science professional development initiatives. They include; teacher turnover, expanding and adding schools and participating teachers, teacher apprehension, building leadership capacity, further engagement of 'tourist' teachers, continuing professional support for teachers, as well as on-going mentoring.

  10. Migraine pathophysiology: lessons from mouse models and human genetics.

    Science.gov (United States)

    Ferrari, Michel D; Klever, Roselin R; Terwindt, Gisela M; Ayata, Cenk; van den Maagdenberg, Arn M J M

    2015-01-01

    Migraine is a common, disabling, and undertreated episodic brain disorder that is more common in women than in men. Unbiased genome-wide association studies have identified 13 migraine-associated variants pointing at genes that cluster in pathways for glutamatergic neurotransmission, synaptic function, pain sensing, metalloproteinases, and the vasculature. The individual pathogenetic contribution of each gene variant is difficult to assess because of small effect sizes and complex interactions. Six genes with large effect sizes were identified in patients with rare monogenic migraine syndromes, in which hemiplegic migraine and non-hemiplegic migraine with or without aura are part of a wider clinical spectrum. Transgenic mouse models with human monogenic-migraine-syndrome gene mutations showed migraine-like features, increased glutamatergic neurotransmission, cerebral hyperexcitability, and enhanced susceptibility to cortical spreading depression, which is the electrophysiological correlate of aura and a putative trigger for migraine. Enhanced susceptibility to cortical spreading depression increased sensitivity to focal cerebral ischaemia, and blocking of cortical spreading depression improved stroke outcome in these mice. Changes in female hormone levels in these mice modulated cortical spreading depression susceptibility in much the same way that hormonal fluctuations affect migraine activity in patients. These findings confirm the multifactorial basis of migraine and might allow new prophylactic options to be developed, not only for migraine but potentially also for migraine-comorbid disorders such as epilepsy, depression, and stroke. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. PENERAPAN MODEL PEMBELAJARAN PROJECT BASED LEARNING BERBASIS LESSON STUDY UNTUK MENINGKATKAN KEAKTIFAN BELAJAR SISWA

    Directory of Open Access Journals (Sweden)

    Aris Yulianto

    2017-03-01

    Full Text Available The purpose of the research is to increase learning activities and learning outcomes students at MTs Sunan Kalijogo. the research is a class action (class action research were conducted in two cycles, each cycle consisting of three meetings. The samples were students of class VII-A second semester of academic year 2014—2015 MTs Sunan Kalijogo the number of students 25 people. The results showed that the students' learning activeness increased learning from the first cycle to the second cycle. Increased student activity occurs because of the learning by applying the model of project based learning is an active student based lesson study to work on worksheets, preparing and completing project tasks with his group. This shows that the project based learning ability increase learning activities and learning outcomes students. Tujuan penelitian ini untuk meningkatkan keaktifan belajar siswa di MTs Sunan Kalijogo. Penelitian ini merupakan penelitian tindakan kelas (PTK yang dilakukan dalam dua siklus dan tiap siklus terdiri atas tiga pertemuan. Sampel penelitian adalah siswa kelas VII A semester genap tahun pelajaran 2014—2015 MTs Sunan Kalijogo dengan jumlah siswa 25 orang. Hasil penelitian ini menunjukkan bahwa keaktifan belajar siswa mengalami peningkatan belajar dari siklus I ke siklus II. Peningkatan keaktifan siswa terjadi karena dalam pembelajaran dengan menerapkan model Project Based Learning berbasis Lesson Study siswa aktif untuk mengerjakan LKS, menyusun dan menyelesaikan tugas proyek bersama kelompoknya. Hal ini menunjukkan bahwa model pembelajaran Project Based Learning dapat meningkatkan keaktifan belajar dan hasil belajar siswa.

  12. Using Model-Based Reasoning for Autonomous Instrument Operation - Lessons Learned From IMAGE/LENA

    Science.gov (United States)

    Johnson, Michael A.; Rilee, Michael L.; Truszkowski, Walt; Bailin, Sidney C.

    2001-01-01

    Model-based reasoning has been applied as an autonomous control strategy on the Low Energy Neutral Atom (LENA) instrument currently flying on board the Imager for Magnetosphere-to-Aurora Global Exploration (IMAGE) spacecraft. Explicit models of instrument subsystem responses have been constructed and are used to dynamically adapt the instrument to the spacecraft's environment. These functions are cast as part of a Virtual Principal Investigator (VPI) that autonomously monitors and controls the instrument. In the VPI's current implementation, LENA's command uplink volume has been decreased significantly from its previous volume; typically, no uplinks are required for operations. This work demonstrates that a model-based approach can be used to enhance science instrument effectiveness. The components of LENA are common in space science instrumentation, and lessons learned by modeling this system may be applied to other instruments. Future work involves the extension of these methods to cover more aspects of LENA operation and the generalization to other space science instrumentation.

  13. Experiences and lessons learned from 30 years of dynamic collector testing, modelling and simulation

    DEFF Research Database (Denmark)

    Perers, Bengt; Kovacs, Peter; Pettersson, Ulrik

    2011-01-01

    Dynamic testing and modeling (in contrast to Steady State line of action) of solar collectors is to prefer in most climates, except for the most extreme locations with clear skies every day. A very important part of dynamic testing and modeling is not only the thermal capacitance correction......, but also the split of the solar radiation absorption modeling, into beam and diffuse and the modeling of the collectors’ incidence angle dependency for both beam and diffuse radiation. These optical features are in most situations more important than the accuracy of the dynamic and thermal loss part...... concerning solar radiation measurements for beam and diffuse including alignment of sensors and test object, that are often not considered, which will be discussed and lessons learned will be given. A misalignment of just a few degrees of the collector test stand or the solar sensors will immediately show up...

  14. Observational constraints on the LLTB model

    CERN Document Server

    Marra, Valerio

    2010-01-01

    We directly compare the concordance LCDM model to the inhomogeneous matter-only alternative represented by LTB void models. To achieve a "democratic" confrontation we explore LLTB models with non-vanishing cosmological constant and perform a global likelihood analysis in the parameter space of cosmological constant and void radius. In our analysis we carefully consider SNe, Hubble constant, CMB and BAO measurements, marginalizing over the age of the universe and the background curvature. We find that the LCDM model is not the only possibility compatible with the observations, and that a matter-only void model is a viable alternative to the concordance model only if the BAO constraints are relaxed. Moreover, we will show that the areas of the parameter space which give a good fit to the observations are always disconnected with the result that a small local void does not significantly affect the parameter extraction for LCDM models.

  15. Lessons from cross-fleet/cross-airline observations - Evaluating the impact of CRM/LOFT training

    Science.gov (United States)

    Butler, Roy E.

    1991-01-01

    A review is presented of the crew resource management/line oriented flight training (CRM/LOFT) program to help determine the level of standardization across fleets and airlines in the critical area of evaluating crew behavior and performance. One of the goals of the project is to verify that check airmen and LOFT instructors within organizations are evaluating CRM issues consistently and that differences observed between fleets are not a function of idiosyncracies on the part of observers. Attention is given to the research tools for crew evaluation.

  16. Reality-Theoretical Models-Mathematics: A Ternary Perspective on Physics Lessons in Upper-Secondary School

    Science.gov (United States)

    Hansson, Lena; Hansson, Örjan; Juter, Kristina; Redfors, Andreas

    2015-01-01

    This article discusses the role of mathematics during physics lessons in upper-secondary school. Mathematics is an inherent part of theoretical models in physics and makes powerful predictions of natural phenomena possible. Ability to use both theoretical models and mathematics is central in physics. This paper takes as a starting point that the…

  17. The Effects of Common Knowledge Construction Model Sequence of Lessons on Science Achievement and Relational Conceptual Change

    Science.gov (United States)

    Ebenezer, Jazlin; Chacko, Sheela; Kaya, Osman Nafiz; Koya, Satya Kiran; Ebenezer, Devairakkam Luke

    2010-01-01

    The purpose of this study was to investigate the effects of the Common Knowledge Construction Model (CKCM) lesson sequence, an intervention based both in conceptual change theory and in Phenomenography, a subset of conceptual change theory. A mixed approach was used to investigate whether this model had a significant effect on 7th grade students'…

  18. Observational Challenges for the Standard FLRW Model

    CERN Document Server

    Buchert, Thomas; Kleinert, Hagen; Roukema, Boudewijn F; Wiltshire, David L

    2015-01-01

    In the context of the "Fourteenth Marcel Grossman Meeting on General Relativity" parallel session DE3, "Large--scale Structure and Statistics", concerning observational issues in cosmology, we summarise some of the main observational challenges for the standard FLRW model and describe how the results presented in the session are related to these challenges.

  19. The ABCs of Family Mealtimes: Observational Lessons for Promoting Healthy Outcomes for Children with Persistent Asthma

    Science.gov (United States)

    Fiese, Barbara H.; Winter, Marcia A.; Botti, Joanna C.

    2011-01-01

    Family mealtimes have the potential to promote healthy child development. This observational study of 200 family mealtimes examined the relation between child health in a group of children (ages 5 to 12) with persistent asthma and 3 dimensions of mealtime interaction: Action, Behavior Control, and Communication. Percent time spent in Action and…

  20. Does an Observer's Content Knowledge Influence the Feedback Offered about Mathematics Lessons?

    Science.gov (United States)

    Peck, Duane C.

    2016-01-01

    The purpose of this study was two-fold. First, feedback from 3 different groups of observers: math content specialists, content specialists in areas other than mathematics, and building principals, was analyzed using an inductive approach to identify themes within the feedback. Second, differences in the feedback offered by participants of the 3…

  1. Research-design model for professional development of teachers: Designing lessons with physics education research

    Directory of Open Access Journals (Sweden)

    Esther Bagno

    2006-09-01

    Full Text Available How can one increase the awareness of teachers to the existence and importance of knowledge gained through physics education research (PER and provide them with capabilities to use it? How can one enrich teachers’ physics knowledge and the related pedagogical content knowledge of topics singled out by PER? In this paper we describe a professional development model that attempts to respond to these needs. We report on a study of the model’s implementation in a program for 22 high-school experienced physics teachers. In this program teachers (in teams of 5-6 developed during a year and a half (about 330 h , several lessons (minimodules dealing with a topic identified as problematic by PER. The teachers employed a systematic research-based approach and used PER findings. The program consisted of three stages, each culminating with a miniconference: 1. Defining teaching and/or learning goals based on content analysis and diagnosis of students’ prior knowledge. 2. Designing the lessons using PER-based instructional strategies. 3. Performing a small-scale research study that accompanies the development process and publishing the results. We describe a case study of one of the groups and bring evidence that demonstrates how the workshop advanced: (a Teachers’ awareness of deficiencies in their own knowledge of physics and pedagogy, and their perceptions about their students’ knowledge; (b teachers’ knowledge of physics and physics pedagogy; (c a systematic research-based approach to the design of lessons; (d the formation of a community of practice; and (e acquaintance with central findings of PER. There was a clear effect on teachers’ practice in the context of the study as indicated by the materials brought to the workshop. The teachers also reported that they continued to use the insights gained, mainly in the topics that were investigated by themselves and by their peers.

  2. Incidentally discovered adrenal tumors: a lesson from observation of 1,444 patients.

    Science.gov (United States)

    Kasperlik-Załuska, A A; Otto, M; Cichocki, A; Rosłonowska, E; Słowińska-Srzednicka, J; Jeske, W; Papierska, L; Zgliczyński, W

    2008-05-01

    This study was aimed at summarizing our experience in the management of 1,444 patients with incidentally found adrenal tumors observed at a single endocrinological centre. Hormonal determinations were performed in all patients at the beginning of the observation period to detect subclinical adrenal hyperfunction. The imaging phenotype on CT and MRI was analyzed for defining the malignant potential of the tumors. Based on the results of these examinations we diagnosed among our cohort probably benign masses in 87%, malignant tumors in 10% (adrenal carcinoma - 9%), and metastases in 3%. Subclinical hyperfunction was diagnosed in 8%; the most frequent was the pre-Cushing's syndrome. A subgroup of 480 patients (33%) was submitted to surgery because of oncological or endocrinological indications. The patients not qualified for surgery were carefully controlled by imaging and hormonal examinations. Malignancy is the most serious risk in the group of patients with incidentally discovered adrenal tumors.

  3. Observations and Modelling of DQ White Dwarfs

    CERN Document Server

    Vornanen, Tommi; Berdyugin, Andrei

    2012-01-01

    We present spectropolarimetric observations and modelling of 12 DQ white dwarfs. Modelling is based on the method presented in Berdyugina et al. (2005). We use the model to fit the C_2 absorption bands to get atmospheric parameters in different configurations, including stellar spots and stratified atmospheres, searching for the best possible fit. We still have problem to solve before we can give temperature estimates based on the Swan bands alone.

  4. Exporting the Buyers Health Care Action Group purchasing model: lessons from other communities.

    Science.gov (United States)

    Christianson, Jon B; Feldman, Roger

    2005-01-01

    When first implemented in Minneapolis and St. Paul, Minnesota, the Buyers Health Care Action Group's (BHCAG) purchasing approach received considerable attention as an employer-managed, consumer-driven health care model embodying many of the principles of managed competition. First BHCAG and, later, a for-profit management company attempted to export this model to other communities. Their efforts were met with resistance from local hospitals and, in many cases, apathy by employers who were expected to be supportive. This experience underscores several difficulties that appear to be inherent in implementing purchasing models based on competing care systems. It also, once again, suggests caution in drawing lessons from community-level experiments in purchasing health care.

  5. Models and observations of sunspot penumbrae

    Institute of Scientific and Technical Information of China (English)

    BORRERO; Juan; Manuel

    2009-01-01

    The mysteries of sunspot penumbrae have been under an intense scrutiny for the past 10 years. During this time, some models have been proposed and refuted, while the surviving ones had to be modified, adapted and evolved to explain the ever-increasing array of observational constraints. In this contribution I will review two of the present models, emphasizing their contributions to this field, but also pinpointing some of their inadequacies to explain a number of recent observations at very high spatial resolution (0.32 ). To help explaining these new observations I propose some modifications to each of those models. These modifications bring those two seemingly opposite models closer together into a general picture that agrees well with recent 3D magneto-hydrodynamic simulations.

  6. Looking beyond general metrics for model evaluation - lessons from an international model intercomparison study

    Science.gov (United States)

    Bouaziz, Laurène; de Boer-Euser, Tanja; Brauer, Claudia; Drogue, Gilles; Fenicia, Fabrizio; Grelier, Benjamin; de Niel, Jan; Nossent, Jiri; Pereira, Fernando; Savenije, Hubert; Thirel, Guillaume; Willems, Patrick

    2016-04-01

    International collaboration between institutes and universities is a promising way to reach consensus on hydrological model development. Education, experience and expert knowledge of the hydrological community have resulted in the development of a great variety of model concepts, calibration methods and analysis techniques. Although comparison studies are very valuable for international cooperation, they do often not lead to very clear new insights regarding the relevance of the modelled processes. We hypothesise that this is partly caused by model complexity and the used comparison methods, which focus on a good overall performance instead of focusing on specific events. We propose an approach that focuses on the evaluation of specific events. Eight international research groups calibrated their model for the Ourthe catchment in Belgium (1607 km2) and carried out a validation in time for the Ourthe (i.e. on two different periods, one of them on a blind mode for the modellers) and a validation in space for nested and neighbouring catchments of the Meuse in a completely blind mode. For each model, the same protocol was followed and an ensemble of best performing parameter sets was selected. Signatures were first used to assess model performances in the different catchments during validation. Comparison of the models was then followed by evaluation of selected events, which include: low flows, high flows and the transition from low to high flows. While the models show rather similar performances based on general metrics (i.e. Nash-Sutcliffe Efficiency), clear differences can be observed for specific events. While most models are able to simulate high flows well, large differences are observed during low flows and in the ability to capture the first peaks after drier months. The transferability of model parameters to neighbouring and nested catchments is assessed as an additional measure in the model evaluation. This suggested approach helps to select, among competing

  7. Models and Observations of Sunspot Penumbrae

    CERN Document Server

    Borrero, J M

    2008-01-01

    The mysteries of sunspot penumbrae have been under an intense scrutiny for the past 10 years. During this time, some models have been proposed and refuted, while the surviving ones had to be modified, adapted and evolved to explain the ever-increasing array of observational constraints. In this contribution I will review two of the present models, emphasizing their contributions to this field, but also pinpointing some of their inadequacies to explain a number of recent observations at very high spatial resolution. To help explaining these new observations I propose some modifications to each of them. These modifications bring those two seemingly opposite models closer together into a general picture that agrees well with recent 3D magneto-hydrodynamic simulations.

  8. Lessons Learned Coaching Teachers in Behavior Management: The PBISplus Coaching Model.

    Science.gov (United States)

    Hershfeldt, Patricia A; Pell, Karen; Sechrest, Richard; Pas, Elise T; Bradshaw, Catherine P

    2012-10-01

    There is growing interest in coaching as a means of promoting professional development and the use of evidence-based practices in schools. This paper describes the PBISplus coaching model used to provide technical assistance for classroom- and school-wide behavior management to elementary schools over the course of three years. This tier-two coaching model was implemented within the context of school-wide Positive Behavioral Interventions and Supports (PBIS) and tested in a 42-school randomized controlled trial. We summarize some of the lessons learned by coaches regarding their efforts to gain access to the administrators, teachers, and student support staff in order to effect change and improve student outcomes. We conclude with a discussion of ways to successfully collaborate with teachers to promote effective classroom- and school-wide behavior management.

  9. Directly observed therapy (DOT) for nonadherent HIV-infected youth: lessons learned, challenges ahead.

    Science.gov (United States)

    Gaur, Aditya H; Belzer, Marvin; Britto, Paula; Garvie, Patricia A; Hu, Chengcheng; Graham, Bobbie; Neely, Michael; McSherry, George; Spector, Stephen A; Flynn, Patricia M

    2010-09-01

    Adherence to medications is critical to optimizing HIV care and is a major challenge in youth. The utility of directly observed therapy (DOT) to improve adherence in youth with HIV remains undefined and prompted this pilot study. Four U.S. sites were selected for this 24-week cooperative group study to assess feasibility and to identify the logistics of providing DOT to HIV-infected youth with demonstrated adherence problems. Once-a-day DOT was provided by DOT facilitators at the participant's choice of a community-based location and DOT tapered over 12 weeks to self-administered therapy based on ongoing adherence assessments. Twenty participants, median age 21 years and median CD4 227 cells/microl, were enrolled. Participants chose their homes for 82% of DOT visits. Compliance with recommended DOT visits was (median) 91%, 91%, and 83% at weeks 4, 8, and 12, respectively. Six participants completed >90% of the study-specified DOT visits and successfully progressed to self-administered therapy (DOT success); only half sustained >90% medication adherence 12 weeks after discontinuing DOT. Participants considered DOT successes were more likely to have higher baseline depression scores (p = 0.046). Via exit surveys participants reported that meeting with the facilitator was easy, DOT increased their motivation to take medications, they felt sad when DOT ended, and 100% would recommend DOT to a friend. In conclusion, this study shows that while community-based DOT is safe, feasible, and as per participant feedback, acceptable to youth, DOT is not for all and the benefits appear short-lived. Depressed youth appear to be one subgroup that would benefit from this intervention. Study findings should help inform the design of larger community-based DOT intervention studies in youth.

  10. Lessons Learned from OMI Observations of Point Source SO2 Pollution

    Science.gov (United States)

    Krotkov, N.; Fioletov, V.; McLinden, Chris

    2011-01-01

    The Ozone Monitoring Instrument (OMI) on NASA Aura satellite makes global daily measurements of the total column of sulfur dioxide (SO2), a short-lived trace gas produced by fossil fuel combustion, smelting, and volcanoes. Although anthropogenic SO2 signals may not be detectable in a single OMI pixel, it is possible to see the source and determine its exact location by averaging a large number of individual measurements. We describe new techniques for spatial and temporal averaging that have been applied to the OMI SO2 data to determine the spatial distributions or "fingerprints" of SO2 burdens from top 100 pollution sources in North America. The technique requires averaging of several years of OMI daily measurements to observe SO2 pollution from typical anthropogenic sources. We found that the largest point sources of SO2 in the U.S. produce elevated SO2 values over a relatively small area - within 20-30 km radius. Therefore, one needs higher than OMI spatial resolution to monitor typical SO2 sources. TROPOMI instrument on the ESA Sentinel 5 precursor mission will have improved ground resolution (approximately 7 km at nadir), but is limited to once a day measurement. A pointable geostationary UVB spectrometer with variable spatial resolution and flexible sampling frequency could potentially achieve the goal of daily monitoring of SO2 point sources and resolve downwind plumes. This concept of taking the measurements at high frequency to enhance weak signals needs to be demonstrated with a GEOCAPE precursor mission before 2020, which will help formulating GEOCAPE measurement requirements.

  11. Evaluation of International Observe the Moon Night: Outcomes, Challenges, and Lessons Learned from Six Years of Data Collection

    Science.gov (United States)

    Buxner, S.; Wenger, M.; Joseph, E.; Jones, A. P.; Bleacher, L.; Shaner, A. J.; Day, B. H.

    2015-12-01

    Evaluation of large public STEM events poses many challenges including data collection of moving crowds, representative sampling, and collecting sufficient data with available resources. International Observe the Moon Night (InOMN) is a yearly event held around the world on a single day coordinated by the Lunar Reconnaissance Orbiter with support from partners around the globe. Each year hundreds of events are held across the United States and in over 50 countries across the world. This distributed event poses even more challenges in its evaluation due to the fact that events vary widely in their implementation and that it is impossible for evaluators to collect data at any more than a small fraction of the events. We present findings of six years of evaluation at InOMN events that implemented varying data collection techniques, incentives, and target outcomes as the event has evolved. Through analysis of these years of data, we have found that InOMN events are hosted by a variety of public and private institutions all over the world including museums, planetaria, schools, universities, observatories, parks, and private businesses and families, over half of which have hosted events for more than one year. Telescopes are present at a majority of the events and lunar science and exploration is often highlighted. Visitors who have been surveyed or interviewed often report being regular attendees at science related events but many were new to InOMN. Many of those surveyed report that they attended with friends and family making their participation a social event. Visitors also reported an increase in knowledge and excitement to learn more about the Moon as a result of their participation in an event. Overall, InOMN events have met both organizers and facilitators' goals. We will discuss the different data collection techniques, challenges encountered and overcome, and lessons learned through this ongoing evaluation effort.

  12. Lessons Learned from the First Two Years of Nature's Notebook, the USA National Phenology Network's Plant and Animal Observation Program

    Science.gov (United States)

    Crimmins, T. M.; Rosemartin, A.; Denny, E. G.; Weltzin, J. F.; Marsh, L.

    2010-12-01

    Nature’s Notebook is the USA National Phenology Network’s (USA-NPN) national-scale plant and animal phenology observation program. The program was launched in March 2009 focusing only on plants; 2010 saw the addition of animals and the name and identity “Nature’s Notebook.” Over these two years, we have learned much about how to effectively recruit, train, and retain participants. We have engaged several thousand participants and can report a retention rate, reflected in the number of registered individuals that report observations, of approximately 25%. In 2009, participants reported observations on 133 species of plants on an average of nine days of the year, resulting in over 151,000 records in the USA-NPN phenology database. Results for the 2010 growing season are still being reported. Some of our most valuable lessons learned have been gleaned from communications with our observers. Through an informal survey, participants indicated that they would like to see more regular and consistent communications from USA-NPN program staff; clear, concise, and readily available training materials; mechanisms to keep them engaged and continuing to participate; and quick turn-around on data summaries. We are using this feedback to shape our program into the future. Another key observation we’ve made about our program is the value of locally and regionally-based efforts to implement Nature’s Notebook; some of our most committed observers are participating through partner programs such as the University of California-Santa Barbara Phenology Stewardship Program, Arbor Day Foundation, and the Great Sunflower Project. Future plans include reaching out to more partner organizations and improving our support for locally-based implementations of the Nature’s Notebook program. We have also recognized that the means for reaching and retaining potential participants in Nature’s Notebook vary greatly across generations. As the majority of our participants to

  13. Are there consistent models giving observable NSI ?

    CERN Document Server

    Martinez, Enrique Fernandez

    2013-01-01

    While the existing direct bounds on neutrino NSI are rather weak, order 10(−)(1) for propagation and 10(−)(2) for production and detection, the close connection between these interactions and new NSI affecting the better-constrained charged letpon sector through gauge invariance make these bounds hard to saturate in realistic models. Indeed, Standard Model extensions leading to neutrino NSI typically imply constraints at the 10(−)(3) level. The question of whether consistent models leading to observable neutrino NSI naturally arises and was discussed in a dedicated session at NUFACT 11. Here we summarize that discussion.

  14. Stratospheric dryness: model simulations and satellite observations

    Directory of Open Access Journals (Sweden)

    J. Lelieveld

    2007-01-01

    Full Text Available The mechanisms responsible for the extreme dryness of the stratosphere have been debated for decades. A key difficulty has been the lack of comprehensive models which are able to reproduce the observations. Here we examine results from the coupled lower-middle atmosphere chemistry general circulation model ECHAM5/MESSy1 together with satellite observations. Our model results match observed temperatures in the tropical lower stratosphere and realistically represent the seasonal and inter-annual variability of water vapor. The model reproduces the very low water vapor mixing ratios (below 2 ppmv periodically observed at the tropical tropopause near 100 hPa, as well as the characteristic tape recorder signal up to about 10 hPa, providing evidence that the dehydration mechanism is well-captured. Our results confirm that the entry of tropospheric air into the tropical stratosphere is forced by large-scale wave dynamics, whereas radiative cooling regionally decelerates upwelling and can even cause downwelling. Thin cirrus forms in the cold air above cumulonimbus clouds, and the associated sedimentation of ice particles between 100 and 200 hPa reduces water mass fluxes by nearly two orders of magnitude compared to air mass fluxes. Transport into the stratosphere is supported by regional net radiative heating, to a large extent in the outer tropics. During summer very deep monsoon convection over Southeast Asia, centered over Tibet, moistens the stratosphere.

  15. Observations and NLTE modeling of Ellerman bombs

    CERN Document Server

    Berlicki, Arkadiusz

    2014-01-01

    Ellerman bombs (EBs) are short-lived and compact structures that are observed well in the wings of the hydrogen H-alpha line. EBs are also observed in the chromospheric CaII lines and in UV continua. H-alpha line profiles of EBs show a deep absorption at the line center and enhanced emission in the line wings. Similar shapes of the line profiles are observed for the CaII IR line at 8542 ang. It is generally accepted that EBs may be considered as compact microflares located in lower solar atmosphere. However, it is still not clear where exactly the emission of EBs is formed in the solar atmosphere. High-resolution spectrophotometric observations of EBs were used for determining of their physical parameters and construction of semi-empirical models. In our analysis we used observations of EBs obtained in the H-alpha and CaII H lines. We also used NLTE numerical codes for the construction of grids of 243 semi-empirical models simulating EBs structures. In this way, the observed emission could be compared with th...

  16. Supporting observation campaigns with high resolution modeling

    Science.gov (United States)

    Klocke, Daniel; Brueck, Matthias; Voigt, Aiko

    2017-04-01

    High resolution simulation in support of measurement campaigns offers a promising and emerging way to create large-scale context for small-scale observations of clouds and precipitation processes. As these simulation include the coupling of measured small-scale processes with the circulation, they also help to integrate the research communities from modeling and observations and allow for detailed model evaluations against dedicated observations. In connection with the measurement campaign NARVAL (August 2016 and December 2013) simulations with a grid-spacing of 2.5 km for the tropical Atlantic region (9000x3300 km), with local refinement to 1.2 km for the western part of the domain, were performed using the icosahedral non-hydrostatic (ICON) general circulation model. These simulations are again used to drive large eddy resolving simulations with the same model for selected days in the high definition clouds and precipitation for advancing climate prediction (HD(CP)2) project. The simulations are presented with the focus on selected results showing the benefit for the scientific communities doing atmospheric measurements and numerical modeling of climate and weather. Additionally, an outlook will be given on how similar simulations will support the NAWDEX measurement campaign in the North Atlantic and AC3 measurement campaign in the Arctic.

  17. Placing Observational Constraints on Massive Star Models

    Science.gov (United States)

    Rosenfield, Philip

    2011-10-01

    The lives and deaths of massive stars are intricately linked to the evolution of galaxies. Yet, despite their integral importance to understanding galaxy evolution, models of massive stars are inconsistent with observations. These uncertainties can be traced to limited observational constraints available for improving massive star models. A sensitive test of the underlying physics of massive stars, e.g., convection, rotation, and mass loss is to measure the ratio of blue core helium burning stars {BHeB} to red core helium burning stars {RHeB}, 5-20Msun stars in the stage evolution immediately following the main sequence. Even the most sophisticated models cannot accurately predict the observed ratio over a range of metallicities, suggesting an insufficient understanding of the underlying physics. However, observational measurements of this ratio over a wide range of environments would provide substantial constraints on the physical parameters governing the evolution of all stars >5 Msun.We propose to place stringent observational constraints on the physics of massive star evolution by uniformly measuring the B/R HeB ratio in a wide range of galaxies. The HST archive contains high quality optical imaging of resolved stellar populations of dozens of nearby galaxies. From the ANGST program, we identified 38 galaxies, spanning 2 dex in metallicity that have significant BHeB and RHeB populations. Using this sample, we will empirically characterize the colors of the BHeB and RHeB sequences as a function of luminosity and metallicity, measure the B/R ratio, and constrain the lifetimes of the BHeB and RHeBs in the Padova stellar evolution models and the Cambridge STARS code.

  18. Constraining Numerical Geodynamo Modeling with Surface Observations

    Science.gov (United States)

    Kuang, Weijia; Tangborn, Andrew

    2006-01-01

    Numerical dynamo solutions have traditionally been generated entirely by a set of self-consistent differential equations that govern the spatial-temporal variation of the magnetic field, velocity field and other fields related to dynamo processes. In particular, those solutions are obtained with parameters very different from those appropriate for the Earth s core. Geophysical application of the numerical results therefore depends on correct understanding of the differences (errors) between the model outputs and the true states (truth) in the outer core. Part of the truth can be observed at the surface in the form of poloidal magnetic field. To understand these differences, or errors, we generate new initial model state (analysis) by assimilating sequentially the model outputs with the surface geomagnetic observations using an optimal interpolation scheme. The time evolution of the core state is then controlled by our MoSST core dynamics model. The final outputs (forecasts) are then compared with the surface observations as a means to test the success of the assimilation. We use the surface geomagnetic data back to year 1900 for our studies, with 5-year forecast and 20-year analysis periods. We intend to use the result; to understand time variation of the errors with the assimilation sequences, and the impact of the assimilation on other unobservable quantities, such as the toroidal field and the fluid velocity in the core.

  19. Looking beyond general metrics for model comparison - lessons from an international model intercomparison study

    Science.gov (United States)

    de Boer-Euser, Tanja; Bouaziz, Laurène; De Niel, Jan; Brauer, Claudia; Dewals, Benjamin; Drogue, Gilles; Fenicia, Fabrizio; Grelier, Benjamin; Nossent, Jiri; Pereira, Fernando; Savenije, Hubert; Thirel, Guillaume; Willems, Patrick

    2017-01-01

    International collaboration between research institutes and universities is a promising way to reach consensus on hydrological model development. Although model comparison studies are very valuable for international cooperation, they do often not lead to very clear new insights regarding the relevance of the modelled processes. We hypothesise that this is partly caused by model complexity and the comparison methods used, which focus too much on a good overall performance instead of focusing on a variety of specific events. In this study, we use an approach that focuses on the evaluation of specific events and characteristics. Eight international research groups calibrated their hourly model on the Ourthe catchment in Belgium and carried out a validation in time for the Ourthe catchment and a validation in space for nested and neighbouring catchments. The same protocol was followed for each model and an ensemble of best-performing parameter sets was selected. Although the models showed similar performances based on general metrics (i.e. the Nash-Sutcliffe efficiency), clear differences could be observed for specific events. We analysed the hydrographs of these specific events and conducted three types of statistical analyses on the entire time series: cumulative discharges, empirical extreme value distribution of the peak flows and flow duration curves for low flows. The results illustrate the relevance of including a very quick flow reservoir preceding the root zone storage to model peaks during low flows and including a slow reservoir in parallel with the fast reservoir to model the recession for the studied catchments. This intercomparison enhanced the understanding of the hydrological functioning of the catchment, in particular for low flows, and enabled to identify present knowledge gaps for other parts of the hydrograph. Above all, it helped to evaluate each model against a set of alternative models.

  20. Orion Flight Test 1 Architecture: Observed Benefits of a Model Based Engineering Approach

    Science.gov (United States)

    Simpson, Kimberly A.; Sindiy, Oleg V.; McVittie, Thomas I.

    2012-01-01

    This paper details how a NASA-led team is using a model-based systems engineering approach to capture, analyze and communicate the end-to-end information system architecture supporting the first unmanned orbital flight of the Orion Multi-Purpose Crew Exploration Vehicle. Along with a brief overview of the approach and its products, the paper focuses on the observed program-level benefits, challenges, and lessons learned; all of which may be applied to improve system engineering tasks for characteristically similarly challenges

  1. Controllability, Observability, and Stability of Mathematical Models

    OpenAIRE

    Iggidr, Abderrahman

    2004-01-01

    International audience; This article presents an overview of three fundamental concepts in Mathematical System Theory: controllability, stability and observability. These properties play a prominent role in the study of mathematical models and in the understanding of their behavior. They constitute the main research subject in Control Theory. Historically the tools and techniques of Automatic Control have been developed for artificial engineering systems but nowadays they are more and more ap...

  2. Evaluation of CNN as anthropomorphic model observer

    Science.gov (United States)

    Massanes, Francesc; Brankov, Jovan G.

    2017-03-01

    Model observers (MO) are widely used in medical imaging to act as surrogates of human observers in task-based image quality evaluation, frequently towards optimization of reconstruction algorithms. In this paper, we explore the use of convolutional neural networks (CNN) to be used as MO. We will compare CNN MO to alternative MO currently being proposed and used such as the relevance vector machine based MO and channelized Hotelling observer (CHO). As the success of the CNN, and other deep learning approaches, is rooted in large data sets availability, which is rarely the case in medical imaging systems task-performance evaluation, we will evaluate CNN performance on both large and small training data sets.

  3. Observation and modelling of urban dew

    Science.gov (United States)

    Richards, Katrina

    Despite its relevance to many aspects of urban climate and to several practical questions, urban dew has largely been ignored. Here, simple observations an out-of-doors scale model, and numerical simulation are used to investigate patterns of dewfall and surface moisture (dew + guttation) in urban environments. Observations and modelling were undertaken in Vancouver, B.C., primarily during the summers of 1993 and 1996. Surveys at several scales (0.02-25 km) show that the main controls on dew are weather, location and site configuration (geometry and surface materials). Weather effects are discussed using an empirical factor, FW . Maximum dew accumulation (up to ~ 0.2 mm per night) is seen on nights with moist air and high FW , i.e., cloudless conditions with light winds. Favoured sites are those with high Ysky and surfaces which cool rapidly after sunset, e.g., grass and well insulated roofs. A 1/8-scale model is designed, constructed, and run at an out-of-doors site to study dew patterns in an urban residential landscape which consists of house lots, a street and an open grassed park. The Internal Thermal Mass (ITM) approach is used to scale the thermal inertia of buildings. The model is validated using data from full-scale sites in Vancouver. Patterns in the model agree with those seen at the full-scale, i.e., dew distribution is governed by weather, site geometry and substrate conditions. Correlation is shown between Ysky and surface moisture accumulation. The feasibility of using a numerical model to simulate urban dew is investigated using a modified version of a rural dew model. Results for simple isolated surfaces-a deciduous tree leaf and an asphalt shingle roof-show promise, especially for built surfaces.

  4. Observational signatures of anisotropic inflationary models

    CERN Document Server

    Ohashi, Junko; Tsujikawa, Shinji

    2013-01-01

    We study observational signatures of two classes of anisotropic inflationary models in which an inflaton field couples to (i) a vector kinetic term F_{mu nu}F^{mu nu} and (ii) a two-form kinetic term H_{mu nu lambda}H^{mu nu lambda}. We compute the corrections from the anisotropic sources to the power spectrum of gravitational waves as well as the two-point cross correlation between scalar and tensor perturbations. The signs of the anisotropic parameter g_* are different depending on the vector and the two-form models, but the statistical anisotropies generally lead to a suppressed tensor-to-scalar ratio r and a smaller scalar spectral index n_s in both models. In the light of the recent Planck bounds of n_s and r, we place observational constraints on several different inflaton potentials such as those in chaotic and natural inflation in the presence of anisotropic interactions. In the two-form model we also find that there is no cross correlation between scalar and tensor perturbations, while in the vector ...

  5. Observations and Modeling of Geospace Energetic Particles

    Science.gov (United States)

    Li, Xinlin

    2016-07-01

    Comprehensive measurements of energetic particles and electric and magnetic fields from state-of-art instruments onboard Van Allen Probes, in a geo-transfer-like orbit, revealed new features of the energetic particles and the fields in the inner magnetosphere and impose new challenges to any quantitative modeling of the physical processes responsible for these observations. Concurrent measurements of energetic particles by satellites in highly inclined low Earth orbits and plasma and fields by satellites in farther distances in the magnetospheres and in the up stream solar wind are the critically needed information for quantitative modeling and for leading to eventual accurate forecast of the variations of the energetic particles in the magnetosphere. In this presentation, emphasis will be on the most recent advance in our understanding of the energetic particles in the magnetosphere and the missing links for significantly advance in our modeling and forecasting capabilities.

  6. Dark energy observational evidence and theoretical models

    CERN Document Server

    Novosyadlyj, B; Shtanov, Yu; Zhuk, A

    2013-01-01

    The book elucidates the current state of the dark energy problem and presents the results of the authors, who work in this area. It describes the observational evidence for the existence of dark energy, the methods and results of constraining of its parameters, modeling of dark energy by scalar fields, the space-times with extra spatial dimensions, especially Kaluza---Klein models, the braneworld models with a single extra dimension as well as the problems of positive definition of gravitational energy in General Relativity, energy conditions and consequences of their violation in the presence of dark energy. This monograph is intended for science professionals, educators and graduate students, specializing in general relativity, cosmology, field theory and particle physics.

  7. INTERVAL OBSERVER FOR A BIOLOGICAL REACTOR MODEL

    Directory of Open Access Journals (Sweden)

    T. A. Kharkovskaia

    2014-05-01

    Full Text Available The method of an interval observer design for nonlinear systems with parametric uncertainties is considered. The interval observer synthesis problem for systems with varying parameters consists in the following. If there is the uncertainty restraint for the state values of the system, limiting the initial conditions of the system and the set of admissible values for the vector of unknown parameters and inputs, the interval existence condition for the estimations of the system state variables, containing the actual state at a given time, needs to be held valid over the whole considered time segment as well. Conditions of the interval observers design for the considered class of systems are shown. They are: limitation of the input and state, the existence of a majorizing function defining the uncertainty vector for the system, Lipschitz continuity or finiteness of this function, the existence of an observer gain with the suitable Lyapunov matrix. The main condition for design of such a device is cooperativity of the interval estimation error dynamics. An individual observer gain matrix selection problem is considered. In order to ensure the property of cooperativity for interval estimation error dynamics, a static transformation of coordinates is proposed. The proposed algorithm is demonstrated by computer modeling of the biological reactor. Possible applications of these interval estimation systems are the spheres of robust control, where the presence of various types of uncertainties in the system dynamics is assumed, biotechnology and environmental systems and processes, mechatronics and robotics, etc.

  8. Science-Grade Observing Systems as Process Observatories: Mapping and Understanding Nonlinearity and Multiscale Memory with Models and Observations

    Science.gov (United States)

    Barros, A. P.; Wilson, A. M.; Miller, D. K.; Tao, J.; Genereux, D. P.; Prat, O.; Petersen, W. A.; Brunsell, N. A.; Petters, M. D.; Duan, Y.

    2015-12-01

    Using the planet as a study domain and collecting observations over unprecedented ranges of spatial and temporal scales, NASA's EOS (Earth Observing System) program was an agent of transformational change in Earth Sciences over the last thirty years. The remarkable space-time organization and variability of atmospheric and terrestrial moist processes that emerged from the analysis of comprehensive satellite observations provided much impetus to expand the scope of land-atmosphere interaction studies in Hydrology and Hydrometeorology. Consequently, input and output terms in the mass and energy balance equations evolved from being treated as fluxes that can be used as boundary conditions, or forcing, to being viewed as dynamic processes of a coupled system interacting at multiple scales. Measurements of states or fluxes are most useful if together they map, reveal and/or constrain the underlying physical processes and their interactions. This can only be accomplished through an integrated observing system designed to capture the coupled physics, including nonlinear feedbacks and tipping points. Here, we first review and synthesize lessons learned from hydrometeorology studies in the Southern Appalachians and in the Southern Great Plains using both ground-based and satellite observations, physical models and data-assimilation systems. We will specifically focus on mapping and understanding nonlinearity and multiscale memory of rainfall-runoff processes in mountainous regions. It will be shown that beyond technical rigor, variety, quantity and duration of measurements, the utility of observing systems is determined by their interpretive value in the context of physical models to describe the linkages among different observations. Second, we propose a framework for designing science-grade and science-minded process-oriented integrated observing and modeling platforms for hydrometeorological studies.

  9. THE DEVELOPMENT OF LECTURE MODEL OF CHEMICAL EDUCATION MANAGEMENT BASED ON LESSON STUDY TO IMPROVE CHEMISTRY TEACHER CANDIDATES’ PROFESIONALISM

    Directory of Open Access Journals (Sweden)

    S.S. Sumarti

    2015-04-01

    Full Text Available The purpose of this research is to produce a lecture model of chemical education management based on lesson study as an effort to improve chemistry teacher candidates’ professionalism. This study used a model of ADDIE (Analysis-Design-Implement-Develop-Evaluate. Based on the results of the reflection, lecturer and team can arrange the post-presentation activities (discussing material theoretically with a variety of management practices in the field. Activities will be carried out by presenting a real problem in the field to find the solution, thus the students’ curiosity about management implementation will be fulfilled. Lecture Model of Chemical Education Management Based on Lesson Study can improve the chemistry teacher candidates’ professionalism, primarily in preparing, presenting and being responsible of their work by learning from their learning experience.

  10. Observational Equivalence of Discrete String Models and Market Models

    NARCIS (Netherlands)

    Kerkhof, F.L.J.; Pelsser, A.

    2002-01-01

    In this paper we show that, contrary to the claim made in Longsta, Santa-Clara, and Schwartz (2001a) and Longsta, Santa-Clara, and Schwartz (2001b), discrete string models are not more parsimonious than market models.In fact, they are found to be observationally equivalent.We derive that, for the es

  11. Lessons from wet gas flow metering systems using differential measurements devices: Testing and flow modelling results

    Energy Technology Data Exchange (ETDEWEB)

    Cazin, J.; Couput, J.P.; Dudezert, C. et al

    2005-07-01

    A significant number of wet gas meters used for high GVF and very high GVF are based on differential pressure measurements. Recent high pressure tests performed on a variety of different DP devices on different flow loops are presented. Application of existing correlations is discussed for several DP devices including Venturi meters. For Venturi meters, deviations vary from 9% when using the Murdock correlation to less than 3 % with physical based models. The use of DP system in a large domain of conditions (Water Liquid Ratio) especially for liquid estimation will require information on the WLR This obviously raises the question of the gas and liquid flow metering accuracy in wet gas meters and highlight needs to understand AP systems behaviour in wet gas flows (annular / mist / annular mist). As an example, experimental results obtained on the influence of liquid film characteristics on a Venturi meter are presented. Visualizations of the film upstream and inside the Venturi meter are shown. They are completed by film characterization. The AP measurements indicate that for a same Lockhart Martinelli parameter, the characteristics of the two phase flow have a major influence on the correlation coefficient. A 1D model is defined and the results are compared with the experiments. These results indicate that the flow regime influences the AP measurements and that a better modelling of the flow phenomena is needed even for allocation purposes. Based on that, lessons and way forward in wet gas metering systems improvement for allocation and well metering are discussed and proposed. (author) (tk)

  12. Constraining Cosmological Models with Different Observations

    Science.gov (United States)

    Wei, J. J.

    2016-07-01

    With the observations of Type Ia supernovae (SNe Ia), scientists discovered that the Universe is experiencing an accelerated expansion, and then revealed the existence of dark energy in 1998. Since the amazing discovery, cosmology has became a hot topic in the physical research field. Cosmology is a subject that strongly depends on the astronomical observations. Therefore, constraining different cosmological models with all kinds of observations is one of the most important research works in the modern cosmology. The goal of this thesis is to investigate cosmology using the latest observations. The observations include SNe Ia, Type Ic Super Luminous supernovae (SLSN Ic), Gamma-ray bursts (GRBs), angular diameter distance of galaxy cluster, strong gravitational lensing, and age measurements of old passive galaxies, etc. In Chapter 1, we briefly review the research background of cosmology, and introduce some cosmological models. Then we summarize the progress on cosmology from all kinds of observations in more details. In Chapter 2, we present the results of our studies on the supernova cosmology. The main difficulty with the use of SNe Ia as standard candles is that one must optimize three or four nuisance parameters characterizing SN luminosities simultaneously with the parameters of an expansion model of the Universe. We have confirmed that one should optimize all of the parameters by carrying out the method of maximum likelihood estimation in any situation where the parameters include an unknown intrinsic dispersion. The commonly used method, which estimates the dispersion by requiring the reduced χ^{2} to equal unity, does not take into account all possible variances among the parameters. We carry out such a comparison of the standard ΛCDM cosmology and the R_{h}=ct Universe using the SN Legacy Survey sample of 252 SN events, and show that each model fits its individually reduced data very well. Moreover, it is quite evident that SLSNe Ic may be useful

  13. Observations and Models of Galaxy Assembly Bias

    Science.gov (United States)

    Campbell, Duncan A.

    2017-01-01

    The assembly history of dark matter haloes imparts various correlations between a halo’s physical properties and its large scale environment, i.e. assembly bias. It is common for models of the galaxy-halo connection to assume that galaxy properties are only a function of halo mass, implicitly ignoring how assembly bias may affect galaxies. Recently, programs to model and constrain the degree to which galaxy properties are influenced by assembly bias have been undertaken; however, the extent and character of galaxy assembly bias remains a mystery. Nevertheless, characterizing and modeling galaxy assembly bias is an important step in understanding galaxy evolution and limiting any systematic effects assembly bias may pose in cosmological measurements using galaxy surveys.I will present work on modeling and constraining the effect of assembly bias in two galaxy properties: stellar mass and star-formation rate. Conditional abundance matching allows for these galaxy properties to be tied to halo formation history to a variable degree, making studies of the relative strength of assembly bias possible. Galaxy-galaxy clustering and galactic conformity, the degree to which galaxy color is correlated between neighbors, are sensitive observational measures of galaxy assembly bias. I will show how these measurements can be used to constrain galaxy assembly bias and the peril of ignoring it.

  14. Lagrangian Observations and Modeling of Marine Larvae

    Science.gov (United States)

    Paris, Claire B.; Irisson, Jean-Olivier

    2017-04-01

    Just within the past two decades, studies on the early-life history stages of marine organisms have led to new paradigms in population dynamics. Unlike passive plant seeds that are transported by the wind or by animals, marine larvae have motor and sensory capabilities. As a result, marine larvae have a tremendous capacity to actively influence their dispersal. This is continuously revealed as we develop new techniques to observe larvae in their natural environment and begin to understand their ability to detect cues throughout ontogeny, process the information, and use it to ride ocean currents and navigate their way back home, or to a place like home. We present innovative in situ and numerical modeling approaches developed to understand the underlying mechanisms of larval transport in the ocean. We describe a novel concept of a Lagrangian platform, the Drifting In Situ Chamber (DISC), designed to observe and quantify complex larval behaviors and their interactions with the pelagic environment. We give a brief history of larval ecology research with the DISC, showing that swimming is directional in most species, guided by cues as diverse as the position of the sun or the underwater soundscape, and even that (unlike humans!) larvae orient better and swim faster when moving as a group. The observed Lagrangian behavior of individual larvae are directly implemented in the Connectivity Modeling System (CMS), an open source Lagrangian tracking application. Simulations help demonstrate the impact that larval behavior has compared to passive Lagrangian trajectories. These methodologies are already the base of exciting findings and are promising tools for documenting and simulating the behavior of other small pelagic organisms, forecasting their migration in a changing ocean.

  15. THE MOTIVATIONAL MODEL OF YOUNG JAPANESE EFL LEARNERS: AFTER GETTING LESSONS BY HOMEROOM TEACHERS

    Directory of Open Access Journals (Sweden)

    Rie Adachi

    2013-01-01

    Full Text Available Abstract: This study focuses on Japanese pupils’ motivation with other attitudinal attitudes about learning English. The writer surveyed the 5th and 6th grade pupils’ motivation and its effect factors at an elementary school in Japan at the end of the school year 2007 and 2008. The main focus of this study is to find the relationship between motivation and effect factors using both the 2007 and 2008 data and to examine differences of the pupils’ attitudes between 2007 and 2008. Since the 2008 school year, pupils have received lessons by not only an assistant language teacher (ALT but also their home room teachers (HRTs. The finding showed that the 2008 and 2007 results were similar in most valuables, but the value of “Motivation” increased in 2008 compared to the previous year. Furthermore, “people around the learner” influenced on motivation more positively. Finally, this study presented a model which could be suggested as one of the motivational models of Japanese pupils for English activities. The writer concluded that the involvement of HRTs brought about generally good effects on pupils’ attitudes in this elementary school at this point.

  16. Modeling the environmental stability of FeS2 nanorods, using lessons from biomineralization.

    Science.gov (United States)

    Barnard, Amanda S; Russo, Salvy P

    2009-03-18

    Previous experimental studies have indicated that the controlled formation of anisotropic pyrite nanoparticles, such as nanorods or nanowires, is dependent on the right combination of solution chemistry and temperature. Similarly, the morphology of the individual nanocrystals during intracellular biomineralization of single nanocrystals has been attributed to the local environmental conditions, as well as the species of the micro-organism. Although there are obvious similarities, using the lessons from biomineralization to assist the laboratory synthesis of anisotropic pyrite nanostructures, and in the anticipation of environmental stability, requires a more detailed understanding of the role played by individual environmental parameters. In the present study we use a multi-scale thermodynamic model, combined with parameters obtained from first principles calculations, to investigate the formation and stability of pyrite nanorods as a function of temperature and chemical environment. The results of our systematic modeling of parameter space predict that the morphology of pyrite nanorods grown in the laboratory, or associated with biomineralization, is more likely to be a function of surface ligands and the biology of the organisms than a function of simpler environmental parameters such as temperature, pressure, concentration of sulfur and adsorption of water.

  17. Lessons learnt: Observation of Grade 4 reading comprehension teaching in South African schools across the Progress in International Reading Literacy Study (PIRLS 2006 achievement spectrum

    Directory of Open Access Journals (Sweden)

    Lisa Zimmerman

    2014-04-01

    Full Text Available The evidence of the huge challenges of literacy development faced by South African learners is primarily gleaned from the results of learners’ external assessments. There is little research which explores, in-depth, the strategies used by teachers to teach reading literacy and reading comprehension specifically. Questions remain about what is going wrong and, most importantly,what can be changed to rectify the poor outcomes of learners. To gain insight into the poor achievement of Grade 4 learners, in South Africa in the Progress in International Reading Literacy Study (PIRLS 2006, six case studies were undertaken. Each school case had a different class average achievement profile ranging from low to high on the PIRLS achievement scale.This article presents findings from the observation of Grade 4 reading comprehension lessons in six schools. The comparison of observations of teaching practices aligned to higher achieving schools, against those of lower performing schools, indicates the discrepancies in the quality of teaching reading comprehension across the schools, and reveals potential foci for teacher development. The value of comparative lesson observation for these purposes is highlighted.

  18. Modern observations and models of Solar flares

    Science.gov (United States)

    Gritsyk, Pavel; Somov, Boris

    As well known, that fast particles propagating along flare loop generate bremsstrahlung hard x-ray emission and gyro-synchrotron microwave emission. We present the self-consistent kinetic description of propagation accelerated particles. The key point of this approach is taking into account the effect of reverse current. In our two-dimensional model the electric field of reverse current has the strong influence to the beam of accelerated particles. It decelerates part of the electrons in the beam and turns back other part of them without significant energy loss. The exact analytical solution for the appropriate kinetic equation with Landau collision integral was found. Using derived distribution function of electrons we’ve calculated evolution of their energy spectrum and plasma heating, coronal microwave emission and characteristics of hard x-ray emission in the corona and in the chromosphere. All results were compared with modern high precision space observations.

  19. The Whisper of Deep Basins: Observation & Modelling

    Science.gov (United States)

    Burjanek, J.; Ermert, L. A.; Poggi, V.; Michel, C.; Fäh, D.

    2013-12-01

    Free oscillations of Earth have been used for a long time to retrieve information about the deep Earth's interior. On a much smaller scale, standing waves develop in deep sedimentary basins and can possibly be used in a similar way. The sensitivity of these waves to subsurface properties makes them a potential source of information about the deep basin characteristics. We investigated the sequence of two-dimensional resonance modes occurring in Rhône Valley, a strongly over-deepened, glacially carved basin with a sediment fill reaching up to 900 m thickness. We obtained two synchronous linear-array recordings of ambient vibrations and analysed them with two different processing techniques. First, both 2D resonance frequencies and their corresponding modal shapes were identified by frequency-domain decomposition of the signal cross-spectral density matrix. Second, time-frequency polarization analysis was applied to support the addressing of the modes and to determine the relative contributions of the vertical and horizontal components of the fundamental in-plane mode. Simplified 2-D finite element models were then used to support the interpretation of the observations. We were able to identify several resonance modes including previously unmeasured higher modes at all investigated locations in the valley. Good agreement was found between results of our study and previous studies, between the two processing techniques and between observed and modelled results. Finally, a parametric study was performed to qualitatively assess the sensitivity of the mode's order, shape and frequency to subsurface properties like bedrock geometry, Poisson's ratio and shear wave velocity of the sediments. We concluded that the sequence of modes as they appear by frequency depends strongly on subsurface properties. Therefore addressing of the higher modes can be done reliably only with prior information on the sediment structure.

  20. Observing and Modeling Earth's Energy Flows

    Science.gov (United States)

    Stevens, Bjorn; Schwartz, Stephen E.

    2012-07-01

    This article reviews, from the authors' perspective, progress in observing and modeling energy flows in Earth's climate system. Emphasis is placed on the state of understanding of Earth's energy flows and their susceptibility to perturbations, with particular emphasis on the roles of clouds and aerosols. More accurate measurements of the total solar irradiance and the rate of change of ocean enthalpy help constrain individual components of the energy budget at the top of the atmosphere to within ±2 W m-2. The measurements demonstrate that Earth reflects substantially less solar radiation and emits more terrestrial radiation than was believed even a decade ago. Active remote sensing is helping to constrain the surface energy budget, but new estimates of downwelling surface irradiance that benefit from such methods are proving difficult to reconcile with existing precipitation climatologies. Overall, the energy budget at the surface is much more uncertain than at the top of the atmosphere. A decade of high-precision measurements of the energy budget at the top of the atmosphere is providing new opportunities to track Earth's energy flows on timescales ranging from days to years, and at very high spatial resolution. The measurements show that the principal limitation in the estimate of secular trends now lies in the natural variability of the Earth system itself. The forcing-feedback-response framework, which has developed to understand how changes in Earth's energy flows affect surface temperature, is reviewed in light of recent work that shows fast responses (adjustments) of the system are central to the definition of the effective forcing that results from a change in atmospheric composition. In many cases, the adjustment, rather than the characterization of the compositional perturbation (associated, for instance, with changing greenhouse gas concentrations, or aerosol burdens), limits accurate determination of the radiative forcing. Changes in clouds contribute

  1. A PHYSICS LESSON DESIGNED ACCORDING TO 7E MODEL WITH THE HELP OF INSTRUCTIONAL TECHNOLOGY (LESSON PLAN

    Directory of Open Access Journals (Sweden)

    Selahattin GONEN

    2010-01-01

    Full Text Available Students enter the classrooms with a preexisting knowledge of science concepts. These science concepts sometimes show inconsistency with the accepted ones by the scientists and called as misconceptions. Studies applied science field have to get possession of abilities that not only detect these misconceptions also help to solve these problems. Hence, instructional methods that correct students’ misconceptions become important. In this sense, a material related to the physics course is designed according to 7E model with the help of instructional technology.

  2. Learning lessons from operational research in infectious diseases: can the same model be used for noncommunicable diseases in developing countries?

    Directory of Open Access Journals (Sweden)

    Bosu WK

    2014-12-01

    Full Text Available William K Bosu Department of Epidemics and Disease Control, West African Health Organisation, Bobo-Dioulasso, Burkina Faso Abstract: About three-quarters of global deaths from noncommunicable diseases (NCDs occur in developing countries. Nearly a third of these deaths occur before the age of 60 years. These deaths are projected to increase, fueled by such factors as urbanization, nutrition transition, lifestyle changes, and aging. Despite this burden, there is a paucity of research on NCDs, due to the higher priority given to infectious disease research. Less than 10% of research on cardiovascular diseases comes from developing countries. This paper assesses what lessons from operational research on infectious diseases could be applied to NCDs. The lessons are drawn from the priority setting for research, integration of research into programs and routine service delivery, the use of routine data, rapid-assessment survey methods, modeling, chemoprophylaxis, and the translational process of findings into policy and practice. With the lines between infectious diseases and NCDs becoming blurred, it is justifiable to integrate the programs for the two disease groups wherever possible, eg, screening for diabetes in tuberculosis. Applying these lessons will require increased political will, research capacity, ownership, use of local expertise, and research funding. Keywords: infectious diseases, noncommunicable diseases, operational research, developing countries, integration

  3. Lessons from Climate Modeling on the Design and Use of Ensembles for Crop Modeling

    Science.gov (United States)

    Wallach, Daniel; Mearns, Linda O.; Ruane, Alexander C.; Roetter, Reimund P.; Asseng, Senthold

    2016-01-01

    Working with ensembles of crop models is a recent but important development in crop modeling which promises to lead to better uncertainty estimates for model projections and predictions, better predictions using the ensemble mean or median, and closer collaboration within the modeling community. There are numerous open questions about the best way to create and analyze such ensembles. Much can be learned from the field of climate modeling, given its much longer experience with ensembles. We draw on that experience to identify questions and make propositions that should help make ensemble modeling with crop models more rigorous and informative. The propositions include defining criteria for acceptance of models in a crop MME, exploring criteria for evaluating the degree of relatedness of models in a MME, studying the effect of number of models in the ensemble, development of a statistical model of model sampling, creation of a repository for MME results, studies of possible differential weighting of models in an ensemble, creation of single model ensembles based on sampling from the uncertainty distribution of parameter values or inputs specifically oriented toward uncertainty estimation, the creation of super ensembles that sample more than one source of uncertainty, the analysis of super ensemble results to obtain information on total uncertainty and the separate contributions of different sources of uncertainty and finally further investigation of the use of the multi-model mean or median as a predictor.

  4. Developing Teachers' Models for Assessing Students' Competence in Mathematical Modelling through Lesson Study

    Science.gov (United States)

    Aydogan Yenmez, Arzu; Erbas, Ayhan Kursat; Cakiroglu, Erdinc; Alacaci, Cengiz; Cetinkaya, Bulent

    2017-01-01

    Applications and modelling have gained a prominent role in mathematics education reform documents and curricula. Thus, there is a growing need for studies focusing on the effective use of mathematical modelling in classrooms. Assessment is an integral part of using modelling activities in classrooms, since it allows teachers to identify and manage…

  5. Lessons Learned from Near Field Modeling and Data Collected at the SPE Chemical Explosions in Jointed Rock Masses

    Science.gov (United States)

    Vorobiev, O.; Ezzedine, S. M.; Hurley, R.; Antoun, T.; Glenn, L.

    2016-12-01

    This work describes the near-field modeling of wave propagation from underground chemicalexplosions conducted at the Nevada National Security Site (NNSS) in fractured granitic rock. Lab testsperformed on granite samples excavated from various locations at the SPE site have shown littlevariability in mechanical properties. Granite at this scale can be considered as an isotropic medium. Wehave shown, however, that on the scale of the pressure waves generated during chemical explosions(tens of meters), the effective mechanical properties may vary significantly and exhibit both elastic andplastic anisotropies due to local variations in joint properties such as spacing orientation, joint aperture,cohesion and saturation. Since including every joint in a discrete fashion in computational model is notfeasible, especially for large-scale calculations ( 1.5 km domain), we have developed a computationaltechnique to upscale mechanical properties for various scales (frequencies) using geophysicalcharacterization conducted during recent SPE tests at the NNSS. Stochastic representation of thesefeatures based on the field characterizations has been implemented into LLNL's Geodyn-L hydrocode.Scale dependency in mechanical properties is important in order to understand how the ground motionscales with yield. We hope that such an approach will not only provide a better prediction of theground motion observed in the SPE (where the yield varies from 100 kg to few tons of TNT equivalent)but also will allow us to extrapolate results of the SPE to sources with bigger yields. We have validatedour computational results by comparing the measured and computed ground motion at various rangesfor experiments of various yields (SPE1-SPE5). Using the new model we performed severalcomputational studies to identify the most important mechanical properties of the rock mass specific tothe SPE site and to understand their roles in the observed ground motion in the near-field. We willpresent a series

  6. Model Planning of Literature Lessons in the Tenth Grade for the 1973/74 School Year

    Science.gov (United States)

    Gromtseva, S. N.

    1976-01-01

    Topics, materials, and assignments are provided for 49 literature lessons for tenth grade, plus review notes. Subject matter includes Gorky, Mayakovsky, Soviet literature in the 1920s, the 1930s, Tolstoi, the Great Patriotic War, Sholokhov, and modern foreign literature. (ND)

  7. What Are the Effects of Science Lesson Planning in Peers?—Analysis of Attitudes and Knowledge Based on an Actor-Partner Interdependence Model

    Science.gov (United States)

    Smit, Robbert; Rietz, Florian; Kreis, Annelies

    2017-04-01

    This study focuses on the effects of collaborative lesson planning by science pre-service teachers on their attitudes and knowledge. In our study, 120 pre-service teachers discussed a preparation for a science inquiry lesson in dyads. The teacher with the lesson preparation had the role of the coachee, while the other was the coach. We investigated the following research questions: (1) Does learning occur between the two peers? and (2) Is the competency in lesson planning affected by the attitude and knowledge of coach and coachee? Based on an actor-partner interdependence model (APIM), we could clarify the relations of pedagogical content knowledge (PCK) and attitudes (ATT) between and within the dyads of coach and coachee, as well as their development over time. Furthermore, the APIM allowed the inclusion of a mediator (lesson planning competency). Both PCK and ATT increased slightly but significantly during our project. ATT and PCK seemed to converge between coach and coachee at the end of the project. However, we could not find any cross-lagged effects, meaning there was no effect of coach on coachee or vice versa over time. Further, preceding PCK showed a significant effect on the competency of lesson planning, but planning competency did not influence succeeding PCK or attitude. Finally, these results are discussed with respect to science teacher education.

  8. Observational signatures of holographic models of inflation

    NARCIS (Netherlands)

    P. McFadden; K. Skenderis

    2009-01-01

    We discuss the phenomenology of recently proposed holographic models of inflation, in which the very early universe is non-geometric and is described by a dual three-dimensional quantum field theory (QFT). We analyze models determined by a specific class of dual QFTs and show that they have the foll

  9. Observations and modelling of snow avalanche entrainment

    Directory of Open Access Journals (Sweden)

    B. Sovilla

    2002-01-01

    Full Text Available In this paper full scale avalanche dynamics measurements from the Italian Pizzac and Swiss Vallée de la Sionne test sites are used to develop a snowcover entrainment model. A detailed analysis of three avalanche events shows that snowcover entrainment at the avalanche front appears to dominate over bed erosion at the basal sliding surface. Furthermore, the distribution of mass within the avalanche body is primarily a function of basal friction. We show that the mass distribution in the avalanche changes the flow dynamics significantly. Two different dynamical models, the Swiss Voellmy-fluid model and the Norwegian NIS model, are used to back calculate the events. Various entrainment methods are investigated and compared to measurements. We demon-strate that the Norwegian NIS model is clearly better able to simulate the events once snow entrainment has been included in the simulations.

  10. Model validation lessons learned: A case study at Oak Ridge National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Ketelle, R.H.; Lee, R.R.; Bownds, J.M. [Oak Ridge National Lab., TN (United States); Rizk, T.A. [North Carolina State Univ., Raleigh, NC (United States)

    1989-11-01

    A groundwater flow and contaminant transport model validation study was performed to determine the applicability of typical groundwater flow models for performance assessment of proposed waste disposal facilities at Oak Ridge, Tennessee. Standard practice site interpretation and groundwater modeling resulted in inaccurate predictions of contaminant transport at a proposed waste disposal site. The site`s complex and heterogeneous geology, the presence of flow dominated by fractured and weathered zones, and the strongly transient character of shallow aquifer recharge and discharge combined to render assumptions of steady-state, homogeneous groundwater flow invalid. The study involved iterative phases of site field investigation and modeling. Subsequent modeling activities focused on generation of a model grid incorporating the observed site geologic heterogeneity, and on establishing and using model boundary conditions based on site data. Time dependent water table configurations, and fixed head boundary conditions were used as input to the refined model in simulating groundwater flow at the site.

  11. Observational Tests of Planet Formation Models

    CERN Document Server

    Sozzetti, A; Latham, D W; Carney, B W; Laird, J B; Stefanik, R P; Boss, A P; Charbonneau, D; O'Donovan, F T; Holman, M J; Winn, J N

    2007-01-01

    We summarize the results of two experiments to address important issues related to the correlation between planet frequencies and properties and the metallicity of the hosts. Our results can usefully inform formation, structural, and evolutionary models of gas giant planets.

  12. Epidemic and intervention modelling – a scientific rationale for policy decisions? Lessons from the 2009 influenza pandemic

    Science.gov (United States)

    Ferguson, Neil M

    2012-01-01

    Abstract Problem Outbreak analysis and mathematical modelling are crucial for planning public health responses to infectious disease outbreaks, epidemics and pandemics. This paper describes the data analysis and mathematical modelling undertaken during and following the 2009 influenza pandemic, especially to inform public health planning and decision-making. Approach Soon after A(H1N1)pdm09 emerged in North America in 2009, the World Health Organization convened an informal mathematical modelling network of public health and academic experts and modelling groups. This network and other modelling groups worked with policy-makers to characterize the dynamics and impact of the pandemic and assess the effectiveness of interventions in different settings. Setting The 2009 A(H1N1) influenza pandemic. Relevant changes Modellers provided a quantitative framework for analysing surveillance data and for understanding the dynamics of the epidemic and the impact of interventions. However, what most often informed policy decisions on a day-to-day basis was arguably not sophisticated simulation modelling, but rather, real-time statistical analyses based on mechanistic transmission models relying on available epidemiologic and virologic data. Lessons learnt A key lesson was that modelling cannot substitute for data; it can only make use of available data and highlight what additional data might best inform policy. Data gaps in 2009, especially from low-resource countries, made it difficult to evaluate severity, the effects of seasonal variation on transmission and the effectiveness of non-pharmaceutical interventions. Better communication between modellers and public health practitioners is needed to manage expectations, facilitate data sharing and interpretation and reduce inconsistency in results. PMID:22511828

  13. Bayesian Network Models for Local Dependence among Observable Outcome Variables

    Science.gov (United States)

    Almond, Russell G.; Mulder, Joris; Hemat, Lisa A.; Yan, Duanli

    2009-01-01

    Bayesian network models offer a large degree of flexibility for modeling dependence among observables (item outcome variables) from the same task, which may be dependent. This article explores four design patterns for modeling locally dependent observations: (a) no context--ignores dependence among observables; (b) compensatory context--introduces…

  14. Can a regional climate model reproduce observed extreme temperatures?

    Directory of Open Access Journals (Sweden)

    Peter F. Craigmile

    2013-10-01

    Full Text Available Using output from a regional Swedish climate model and observations from the Swedish synoptic observational network, we compare seasonal minimum temperatures from model output and observations using marginal extreme value modeling techniques. We make seasonal comparisons using generalized extreme value models and empirically estimate the shift in the distribution as a function of the regional climate model values, using the Doksum shift function. Spatial and temporal comparisons over south central Sweden are made by building hierarchical Bayesian generalized extreme value models for the observed minima and regional climate model output. Generally speaking the regional model is surprisingly well calibrated for minimum temperatures. We do detect a problem in the regional model to produce minimum temperatures close to 0◦C. The seasonal spatial effects are quite similar between data and regional model. The observations indicate relatively strong warming, especially in the northern region. This signal is present in the regional model, but is not as strong.

  15. Television Advertising and Children's Observational Modeling.

    Science.gov (United States)

    Atkin, Charles K.

    This paper assesses advertising effects on children and adolescents from a social learning theory perspective, emphasizing imitative performance of vicariously reinforced consumption stimuli. The basic elements of social psychologist Albert Bandura's modeling theory are outlined. Then specific derivations from the theory are applied to the problem…

  16. Bicycle Rider Control: Observations, Modeling & Experiments

    NARCIS (Netherlands)

    Kooijman, J.D.G.

    2012-01-01

    Bicycle designers traditionally develop bicycles based on experience and trial and error. Adopting modern engineering tools to model bicycle and rider dynamics and control is another method for developing bicycles. This method has the potential to evaluate the complete design space, and thereby dev

  17. Regional policy models for forest biodiversity analysis: lessons from coastal Oregon.

    Science.gov (United States)

    Johnson, K Norman; Duncan, Sally; Spies, Thomas A

    2007-01-01

    The crisis in the early 1990s over conservation of biodiversity in the forests of the Pacific Northwest caused an upheaval in forest policies for public and private landowners. These events led to the development of the Coastal Landscape Assessment and Modeling Study (CLAMS) for the Coast Range Physiographic Province of Oregon, a province containing over two million hectares of forest with a complex mixture of public and private ownership. Over a decade, CLAMS scientists developed regional data bases and tools to enable assessments of the implications of current policies for biodiversity and have begun using these data and tools to test ideas for solving policy problems. We summarize here four main lessons from our work: (1) Regional ecosystem perspectives, while rewarding, are difficult to achieve. Helping policy makers and the public understand biodiversity policies for an entire province can assist in developing more reasoned policies. However, this result is difficult to achieve because needed scientific building blocks generally do not exist, few policy institutions address regional cross-ownership issues, people can find it difficult to take a regional view, and the appropriate region for analysis changes with the policy problem. (2) Interest in environmental policy analysis may come as much from a pursuit of power as a pursuit of understanding. Biodiversity policy analyses are often viewed as weapons in an ongoing political battle. Also, results that might destabilize existing policies generally will not be well received by those in power. (3) The relationship of regional analyses to civic processes remains challenging and unsettled. Communication between citizens and scientists takes real effort. Also, collaborative processes both inspire and constrain regional policy analysis, and scientific work often proceeds at a different pace than these processes. In the end, CLAMS's most important effect on the civic dialogue may be to change how people think about

  18. A New Hybrid Model Rotor Flux Observer and Its Application

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A new hybrid model rotor flux observer, based on a new voltage model, is presented. In the first place, the voltage model of an induction machine was constructed by using the modeling method discussed in this paper and then the current model using a flux feedback was adopted in this flux observer. Secondly, the two models were combined via a filter and then the rotor flux observer was established. In the M-T synchronous coordinate, the observer was analyzed theoretically and several important functions were derived. A comparison between the observer and the traditional models was made using Matlab software. The simulation results show that the observer model had a better performance than the traditional model.

  19. Observation Constraints on the Simplified GCG Model

    Institute of Scientific and Technical Information of China (English)

    DONG Su-Mei; WU Pu-Xun

    2007-01-01

    A simplified version of generalized Chaplygin gas (GCG) as a dark energy model is studied. By using the latest 162 ESSENCE type la supernovae (Sne la) data, 30 high redshift Sne la data, the baryonk acoustic oscillation peak from SDSS and the CMB data from WMAP3, a strong constraint on this simplified GCG model is obtained. At the 95.4% confidence level we obtain 0.21 ≤ Ωm ≤ 0.31 and 0.994 ≤ a ≤ 1.0 with the best fit fim = 0.25 and a = 1. This best fit scenario corresponds to an accelerating universe with qo ~_0.65 and z ~- 0.81 (a redshift of cosmic phase transition from deceleration to acceleration).

  20. Observations and modelling of snow avalanche entrainment

    OpenAIRE

    2002-01-01

    In this paper full scale avalanche dynamics measurements from the Italian Pizzac and Swiss Vallée de la Sionne test sites are used to develop a snowcover entrainment model. A detailed analysis of three avalanche events shows that snowcover entrainment at the avalanche front appears to dominate over bed erosion at the basal sliding surface. Furthermore, the distribution of mass within the avalanche body is primarily a function of basal fric...

  1. Structural equation modeling for observational studies

    Science.gov (United States)

    Grace, J.B.

    2008-01-01

    Structural equation modeling (SEM) represents a framework for developing and evaluating complex hypotheses about systems. This method of data analysis differs from conventional univariate and multivariate approaches familiar to most biologists in several ways. First, SEMs are multiequational and capable of representing a wide array of complex hypotheses about how system components interrelate. Second, models are typically developed based on theoretical knowledge and designed to represent competing hypotheses about the processes responsible for data structure. Third, SEM is conceptually based on the analysis of covariance relations. Most commonly, solutions are obtained using maximum-likelihood solution procedures, although a variety of solution procedures are used, including Bayesian estimation. Numerous extensions give SEM a very high degree of flexibility in dealing with nonnormal data, categorical responses, latent variables, hierarchical structure, multigroup comparisons, nonlinearities, and other complicating factors. Structural equation modeling allows researchers to address a variety of questions about systems, such as how different processes work in concert, how the influences of perturbations cascade through systems, and about the relative importance of different influences. I present 2 example applications of SEM, one involving interactions among lynx (Lynx pardinus), mongooses (Herpestes ichneumon), and rabbits (Oryctolagus cuniculus), and the second involving anuran species richness. Many wildlife ecologists may find SEM useful for understanding how populations function within their environments. Along with the capability of the methodology comes a need for care in the proper application of SEM.

  2. Research on Lesson Planing Model of Advanced Mathematics%高等数学备课模式的研究

    Institute of Scientific and Technical Information of China (English)

    邱云兰

    2014-01-01

    Lesson planning is an endless re-creation proj ect,it needs the grasp of the knowledge and skills,processes and methods,attitudes and values.New curriculum not only challenges the traditional or-ganizational model,but also the lesson planning.Prepareing the lesson planning and grasp the main idea are tne key.In teaching process,there should be included interesting mathematical problems,mathematical col-orful anecdotes and outstanding mathematical conj ecture,which can serve the students a strong desire for knowledge and creativity to explore the unknown mysteries of motivation.%备课是一项无止境的再“创作”工程。备课要把握知识与技能、过程与方法、情感态度与价值观的要求。备教材、备教法、备学生、备学法,对学生学习高等数学(如下简称高数)有较大的影响,影响学生思维、兴趣和素质的提高。将生动有趣的数学名题、多姿多彩的数学轶事、悬而末决的数学猜想、似是而非的数学饽论,巧妙地贯穿在相应的备课环节之中,从而使学生产生对高数学习的浓厚兴趣和创造探索的动力。

  3. Interacting Dark Energy Models and Observations

    Science.gov (United States)

    Shojaei, Hamed; Urioste, Jazmin

    2017-01-01

    Dark energy is one of the mysteries of the twenty first century. Although there are candidates resembling some features of dark energy, there is no single model describing all the properties of dark energy. Dark energy is believed to be the most dominant component of the cosmic inventory, but a lot of models do not consider any interaction between dark energy and other constituents of the cosmic inventory. Introducing an interaction will change the equation governing the behavior of dark energy and matter and creates new ways to explain cosmic coincidence problem. In this work we studied how the Hubble parameter and density parameters evolve with time in the presence of certain types of interaction. The interaction serves as a way to convert dark energy into matter to avoid a dark energy-dominated universe by creating new equilibrium points for the differential equations. Then we will use numerical analysis to predict the values of distance moduli at different redshifts and compare them to the values for the distance moduli obtained by WMAP (Wilkinson Microwave Anisotropy Probe). Undergraduate Student

  4. Characterizing and modeling of an 88 MW grate-fired boiler burning wheat straw: Experience and lessons

    DEFF Research Database (Denmark)

    Yin, Chungen; Rosendahl, Lasse Aistrup; Clausen, Sønnik

    2012-01-01

    an acceptable agreement. The discrepancies are analyzed from different aspects. The lessons learned and experience gained from this and other case studies are summarized and discussed in detail, which can facilitate the modeling validation effort as well as improve grate-firing technology. Some of the addressed......Grate-firing is one of the main technologies currently used for biomass combustion for heat and power production. However, grate-firing is yet to be further developed, towards a better technology for biomass combustion, particularly towards higher efficiency, lower emissions, and better reliability...... and availability. To better understand grate-firing of biomass and to establish a reliable but relatively simple Computational Fluid Dynamics (CFD) modeling methodology for industrial applications, biomass combustion in a number of different grate boilers has been measured and modeled. As one of the case studies...

  5. Observations, Modeling and Theory of Debris Disks

    CERN Document Server

    Matthews, Brenda C; Wyatt, Mark C; Bryden, Geoff; Eiroa, Carlos

    2014-01-01

    Main sequence stars, like the Sun, are often found to be orbited by circumstellar material that can be categorized into two groups, planets and debris. The latter is made up of asteroids and comets, as well as the dust and gas derived from them, which makes debris disks observable in thermal emission or scattered light. These disks may persist over Gyrs through steady-state evolution and/or may also experience sporadic stirring and major collisional breakups, rendering them atypically bright for brief periods of time. Most interestingly, they provide direct evidence that the physical processes (whatever they may be) that act to build large oligarchs from micron-sized dust grains in protoplanetary disks have been successful in a given system, at least to the extent of building up a significant planetesimal population comparable to that seen in the Solar System's asteroid and Kuiper belts. Such systems are prime candidates to host even larger planetary bodies as well. The recent growth in interest in debris dis...

  6. Brokering access to massive climate and landscape data via web services: observations and lessons learned after five years of the Geo Data Portal project.

    Science.gov (United States)

    Blodgett, D. L.; Walker, J. I.; Read, J. S.

    2015-12-01

    The USGS Geo Data Portal (GDP) project started in 2010 with the goal of providing climate and landscape model output data to hydrology and ecology modelers in model-ready form. The system takes a user-specified collection of polygons and a gridded time series dataset and returns a time series of spatial statistics for each polygon. The GDP is designed for scalability and is generalized such that any data, hosted anywhere on the Internet adhering to the NetCDF-CF conventions, can be processed. Five years into the project, over 600 unique users from more than 200 organizations have used the system's web user interface and some datasets have been accessed thousands of times. In addition to the web interface, python and R client libraries have seen steady usage growth and several third-party web applications have been developed to use the GDP for easy data access. Here, we will present lessons learned and improvements made after five years of operation of the system's user interfaces, processing server, and data holdings. A vision for the future availability and processing of massive climate and landscape data will be outlined.

  7. East Meets West: Rome. Grade 6 Model Lesson for Unit V. California History-Social Science Course Models.

    Science.gov (United States)

    Zachlod, Michelle, Ed.

    This unit for sixth-grade students provides a fuller understanding of Julius Caesar's significance. Before students delve into the sample topic, they need an understanding of Roman values, lore, republican ideals, and structure of early Roman history. The first few activities in this lesson are to be taught prior to beginning the actual study of…

  8. East Meets West: Rome. Grade 6 Model Lesson for Unit V. California History-Social Science Course Models.

    Science.gov (United States)

    Zachlod, Michelle, Ed.

    This unit for sixth-grade students provides a fuller understanding of Julius Caesar's significance. Before students delve into the sample topic, they need an understanding of Roman values, lore, republican ideals, and structure of early Roman history. The first few activities in this lesson are to be taught prior to beginning the actual study of…

  9. Regional gravity field modelling from GOCE observables

    Science.gov (United States)

    Pitoňák, Martin; Šprlák, Michal; Novák, Pavel; Tenzer, Robert

    2017-01-01

    In this article we discuss a regional recovery of gravity disturbances at the mean geocentric sphere approximating the Earth over the area of Central Europe from satellite gravitational gradients. For this purpose, we derive integral formulas which allow converting the gravity disturbances onto the disturbing gravitational gradients in the local north-oriented frame (LNOF). The derived formulas are free of singularities in case of r ≠ R . We then investigate three numerical approaches for solving their inverses. In the initial approach, the integral formulas are firstly modified for solving individually the near- and distant-zone contributions. While the effect of the near-zone gravitational gradients is solved as an inverse problem, the effect of the distant-zone gravitational gradients is computed by numerical integration from the global gravitational model (GGM) TIM-r4. In the second approach, we further elaborate the first scenario by reducing measured gravitational gradients for gravitational effects of topographic masses. In the third approach, we apply additional modification by reducing gravitational gradients for the reference GGM. In all approaches we determine the gravity disturbances from each of the four accurately measured gravitational gradients separately as well as from their combination. Our regional gravitational field solutions are based on the GOCE EGG_TRF_2 gravitational gradients collected within the period from November 1 2009 until January 11 2010. Obtained results are compared with EGM2008, DIR-r1, TIM-r1 and SPW-r1. The best fit, in terms of RMS (2.9 mGal), is achieved for EGM2008 while using the third approach which combine all four well-measured gravitational gradients. This is explained by the fact that a-priori information about the Earth's gravitational field up to the degree and order 180 was used.

  10. Impact of Model and Observation Error on Assimilating Snow Cover Fraction Observations

    Science.gov (United States)

    Arsenault, Kristi R.

    Accurately modeling or observing snow cover fraction (SCF) estimates, which represent fractional snow cover area within a gridcell, can help with better understanding earth system dynamics, improving weather and climate prediction, and providing end-use water solutions. Seeking to obtain more accurate snowpack estimates, high resolution snow cover fraction observations are assimilated with different data assimilation (DA) methods within a land surface model (LSM). The LSM simulates snowpack states, snow water equivalent and snow depth, to obtain improved snowpack estimates known as the analysis. Data assimilation experiments are conducted for two mountainous areas where high spatial snow variability occurs, which can impact realistic snowpack representation for different hydrological and meteorological applications. Consequently, the experiments are conducted at higher model resolutions to better capture this variability. This study focuses on four key aspects of how assimilating SCF observations may improve snowpack estimates and impact the LSM overall. These include investigating the role of data assimilation method complexity, evaluating the impact of model and observational errors on snow state analysis estimates, improving the model's SCF representation for assimilation using observation operators, and examining subsequent model state and flux impacts when SCF observations are assimilated. A simpler direct insertion (DI) and a more complex ensemble Kalman filter (EnKF) data assimilation method were applied. The more complex method proved to be superior to the simpler one; however, this method required accounting for more realistic observational and model errors. Also, the EnKF method required an ensemble of model forecasts, in which bias in the ensemble generation was found and removed. Reducing this bias improved the model snowpack estimates. Detection and geolocation errors in the satellite-based snow cover fraction observations also contributed to degrading

  11. Starspots, stellar cycles and stellar flares: Lessons from solar dynamo models

    Science.gov (United States)

    Choudhuri, Arnab Rai

    2017-01-01

    In this review, we discuss whether the present solar dynamo models can be extrapolated to explain various aspects of stellar activity. We begin with a summary of the following kinds of data for solar-like stars: (i) data pertaining to stellar cycles from Ca H/K emission over many years; (ii) X-ray data indicating hot coronal activity; (iii) starspot data (especially about giant polar spots); and (iv) data pertaining to stellar superflares. Then we describe the current status of solar dynamo modelling—giving an introduction to the flux transport dynamo model, the currently favoured model for the solar cycle. While an extrapolation of this model to solar-like stars can explain some aspects of observational data, some other aspects of the data still remain to be theoretically explained. It is not clear right now whether we need a different kind of dynamo mechanism for stars having giant starspots or producing very strong superflares.

  12. Teacher Training: The Demonstration Lesson

    Science.gov (United States)

    Moore, Alan C.

    1977-01-01

    A teacher training technique is discussed involving a demonstration class given by a local teacher and observed by prospective teachers. After the class a discussion is held analyzing lesson content and teaching techniques. (CHK)

  13. Fireball and cannonball models of gamma ray bursts confront observations

    OpenAIRE

    Dar, Arnon

    2005-01-01

    The two leading contenders for the theory of gamma-ray bursts (GRBs) and their afterglows, the Fireball and Cannonball models, are compared and their predictions are confronted, within space limitations, with key GRB observations, including recent observations with SWIFT

  14. Model-independent inference on compact-binary observations

    OpenAIRE

    Mandel, Ilya; Farr, Will M.; Colonna, Andrea; Stevenson, Simon; Tiňo, Peter; Veitch, John

    2016-01-01

    The recent advanced LIGO detections of gravitational waves from merging binary black holes enhance the prospect of exploring binary evolution via gravitational-wave observations of a population of compact-object binaries. In the face of uncertainty about binary formation models, model-independent inference provides an appealing alternative to comparisons between observed and modelled populations. We describe a procedure for clustering in the multi-dimensional parameter space of observations t...

  15. Testing Models: A Key Aspect to Promote Teaching Activities Related to Models and Modelling in Biology Lessons?

    Science.gov (United States)

    Krell, Moritz; Krüger, Dirk

    2016-01-01

    This study investigated biology teachers' (N = 148) understanding of models and modelling (MoMo), their model-related teaching activities and relations between the two. A framework which distinguishes five aspects of MoMo in science ("nature of models," "multiple models," "purpose of models," "testing…

  16. Testing Models: A Key Aspect to Promote Teaching Activities Related to Models and Modelling in Biology Lessons?

    Science.gov (United States)

    Krell, Moritz; Krüger, Dirk

    2016-01-01

    This study investigated biology teachers' (N = 148) understanding of models and modelling (MoMo), their model-related teaching activities and relations between the two. A framework which distinguishes five aspects of MoMo in science ("nature of models," "multiple models," "purpose of models," "testing…

  17. Reliable groundwater levels: failures and lessons learned from modeling and monitoring studies

    Science.gov (United States)

    Van Lanen, Henny A. J.

    2017-04-01

    Adequate management of groundwater resources requires an a priori assessment of impacts of intended groundwater abstractions. Usually, groundwater flow modeling is used to simulate the influence of the planned abstraction on groundwater levels. Model performance is tested by using observed groundwater levels. Where a multi-aquifer system occurs, groundwater levels in the different aquifers have to be monitored through observation wells with filters at different depths, i.e. above the impermeable clay layer (phreatic water level) and beneath (artesian aquifer level). A reliable artesian level can only be measured if the space between the outer wall of the borehole (vertical narrow shaft) and the observation well is refilled with impermeable material at the correct depth (post-drilling phase) to prevent a vertical hydraulic connection between the artesian and phreatic aquifer. We were involved in improper refilling, which led to impossibility to monitor reliable artesian aquifer levels. At the location of the artesian observation well, a freely overflowing spring was seen, which implied water leakage from the artesian aquifer affected the artesian groundwater level. Careful checking of the monitoring sites in a study area is a prerequisite to use observations for model performance assessment. After model testing the groundwater model is forced with proposed groundwater abstractions (sites, extraction rates). The abstracted groundwater volume is compensated by a reduction of groundwater flow to the drainage network and the model simulates associated groundwater tables. The drawdown of groundwater level is calculated by comparing the simulated groundwater level with and without groundwater abstraction. In lowland areas, such as vast areas of the Netherlands, the groundwater model has to consider a variable drainage network, which means that small streams only carry water during the wet winter season, and run dry during the summer. The main streams drain groundwater

  18. The Challenge of Modelling the Meteorology of Dust Emission: Lessons Learned from the Desert Storms Project

    Science.gov (United States)

    Knippertz, Peter; Marsham, John H.; Cowie, Sophie; Fiedler, Stephanie; Heinold, Bernd; Jemmett-Smith, Bradley; Pantillon, Florian; Schepanski, Kerstin; Roberts, Alexander; Pope, Richard; Gilkeson, Carl; Hubel, Eva

    2016-04-01

    Mineral dust plays an important role in the Earth system, but a reliable quantification of the global dust budget is still not possible due to a lack of observations and insufficient representation of relevant processes in climate and weather models. Five years ago, the Desert Storms project funded by the European Research Council set out to reduce these uncertainties. Its aims were to (1) improve the understanding of key meteorological mechanisms of peak wind generation in dust emission regions (particularly in northern Africa), (2) assess their relative importance, (3) evaluate their representation in models, (4) determine model sensitivities with respect to resolution and model physics, and (5) explore the usefulness of new approaches for model improvements. Here we give an overview of the most significant findings: (1) The morning breakdown of nocturnal low-level jets is an important emission mechanism, but details depend crucially on nighttime stability, which is often badly handled by models. (2) Convective cold pools are a key control on summertime dust emission over northern Africa, directly and through their influence on the heat low; they are severely misrepresented by models using parameterized convection. A new scheme based on downdraft mass flux has been developed that can mitigate this problem. (3) Mobile cyclones make a relatively unimportant contribution, except for northeastern Africa in spring. (4) A new global climatology of dust devils identifies local hotspots but suggests a minor contribution to the global dust budget in contrast to previous studies. A new dust-devil parameterization based on data from large-eddy simulations will be presented. (5) The lack of sufficient observations and misrepresentation of physical processes lead to a considerable uncertainty and biases in (re)analysis products. (6) Variations in vegetation-related surface roughness create small-scale wind variability and support long-term dust trends in semi-arid areas.

  19. Correlation between human observer performance and model observer performance in differential phase contrast CT

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ke; Garrett, John [Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, Wisconsin 53705 (United States); Chen, Guang-Hong [Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, Wisconsin 53705 and Department of Radiology, University of Wisconsin-Madison, 600 Highland Avenue, Madison, Wisconsin 53792 (United States)

    2013-11-15

    Purpose: With the recently expanding interest and developments in x-ray differential phase contrast CT (DPC-CT), the evaluation of its task-specific detection performance and comparison with the corresponding absorption CT under a given radiation dose constraint become increasingly important. Mathematical model observers are often used to quantify the performance of imaging systems, but their correlations with actual human observers need to be confirmed for each new imaging method. This work is an investigation of the effects of stochastic DPC-CT noise on the correlation of detection performance between model and human observers with signal-known-exactly (SKE) detection tasks.Methods: The detectabilities of different objects (five disks with different diameters and two breast lesion masses) embedded in an experimental DPC-CT noise background were assessed using both model and human observers. The detectability of the disk and lesion signals was then measured using five types of model observers including the prewhitening ideal observer, the nonprewhitening (NPW) observer, the nonprewhitening observer with eye filter and internal noise (NPWEi), the prewhitening observer with eye filter and internal noise (PWEi), and the channelized Hotelling observer (CHO). The same objects were also evaluated by four human observers using the two-alternative forced choice method. The results from the model observer experiment were quantitatively compared to the human observer results to assess the correlation between the two techniques.Results: The contrast-to-detail (CD) curve generated by the human observers for the disk-detection experiments shows that the required contrast to detect a disk is inversely proportional to the square root of the disk size. Based on the CD curves, the ideal and NPW observers tend to systematically overestimate the performance of the human observers. The NPWEi and PWEi observers did not predict human performance well either, as the slopes of their CD

  20. 2 types of spicules "observed" in 3D realistic models

    CERN Document Server

    Martínez-Sykora, Juan

    2010-01-01

    Realistic numerical 3D models of the outer solar atmosphere show two different kind of spicule-like phenomena, as also observed on the solar limb. The numerical models are calculated using the 2 types of spicules "observed" in 3D realistic models Oslo Staggered Code (OSC) to solve the full MHD equations with non-grey and NLTE radiative transfer and thermal conduction along the magnetic field lines. The two types of spicules arise as a natural result of the dynamical evolution in the models. We discuss the different properties of these two types of spicules, their differences from observed spicules and what needs to be improved in the models.

  1. Observation-Based Modeling for Model-Based Testing

    NARCIS (Netherlands)

    Kanstrén, T.; Piel, E.; Gross, H.-G.

    2009-01-01

    One of the single most important reasons that modeling and modelbased testing are not yet common practice in industry is the perceived difficulty of making the models up to the level of detail and quality required for their automated processing. Models unleash their full potential only through suffi

  2. Observation-Based Modeling for Model-Based Testing

    NARCIS (Netherlands)

    Kanstrén, T.; Piel, E.; Gross, H.-G.

    2009-01-01

    One of the single most important reasons that modeling and modelbased testing are not yet common practice in industry is the perceived difficulty of making the models up to the level of detail and quality required for their automated processing. Models unleash their full potential only through

  3. Modelling skin disease: lessons from the worlds of mathematics, physics and computer science.

    Science.gov (United States)

    Gilmore, Stephen

    2005-05-01

    Theoretical biology is a field that attempts to understand the complex phenomena of life in terms of mathematical and physical principles. Likewise, theoretical medicine employs mathematical arguments and models as a methodology in approaching the complexities of human disease. Naturally, these concepts can be applied to dermatology. There are many possible methods available in the theoretical investigation of skin disease. A number of examples are presented briefly. These include the mathematical modelling of pattern formation in congenital naevi and erythema gyratum repens, an information-theoretic approach to the analysis of genetic networks in autoimmunity, and computer simulations of early melanoma growth. To conclude, an analogy is drawn between the behaviour of well-known physical processes, such as earthquakes, and the spatio-temporal evolution of skin disease. Creating models in skin disease can lead to predictions that can be investigated experimentally or by observation and offer the prospect of unexpected or important insights into pathogenesis.

  4. Tests of scanning model observers for myocardial SPECT imaging

    Science.gov (United States)

    Gifford, H. C.; Pretorius, P. H.; Brankov, J. G.

    2009-02-01

    Many researchers have tested and applied human-model observers as part of their evaluations of reconstruction methods for SPECT perfusion imaging. However, these model observers have generally been limited to signal-known- exactly (SKE) detection tasks. Our objective is to formulate and test scanning model observers that emulate humans in detection-localization tasks involving perfusion defects. Herein, we compare several models based on the channelized nonprewhitening (CNPW) observer. Simulated Tc-99m images of the heart with and without defects were created using a mathematical anthropomorphic phantom. Reconstructions were performed with an iterative algorithm and postsmoothed with a 3D Gaussian filter. Human and model-observer studies were conducted to assess the optimal number of iterations and the smoothing level of the filter. The human-observer study was a multiple-alternative forced-choice (MAFC) study with five defects. The CNPW observer performed the MAFC study, but also performed an SKE-but-variable (SKEV) study and a localization ROC (LROC) study. A separate LROC study applied an observer based on models of human search in mammograms. The amount of prior knowledge about the possible defects differed for these four model-observer studies. The trend was towards improved agreement with the human observers as prior knowledge decreased.

  5. Understanding complex systems: lessons from Auzoux's and von Hagens's anatomical models

    Indian Academy of Sciences (India)

    Antonio G Valdecasas; Ana M Correas; Carmen R Guerrero; Jesús Juez

    2009-12-01

    Animal and human anatomy is among the most complex systems known, and suitable teaching methods have been of great importance in the progress of knowledge. Examining the human body is part of the process by which medical students come to understand living forms. However, the need to preserve cadavers has led to the development of various techniques to manufacture models for teaching purposes. A variety of materials, such as wax, wood, papier-mâché, or glass, have long been used to construct animal and plant models. In the case of the human body, the most innovative, yet controversial, method of preservation has been plastination, invented by the German physician Gunther von Hagens, by which actual human bodies are preserved as odourless and aesthetic models for teaching and exhibitions. We point out in our study that the ‘hands-on’ approach that some anatomical models allow, namely, the (clastic) disassembly and reassembly of the parts of complex systems and their models, is not only a crucial tool for learning, but is far superior to the simple passive observation that rigid, single-piece models allow. And what is valid for the learning of anatomy can be generalized to the acquisition of knowledge of other complex physical systems.

  6. The ABC’s of Family Mealtimes: Observational Lessons for Promoting Healthy Outcomes for Children with Persistent Asthma

    OpenAIRE

    2011-01-01

    Shared family mealtimes have been identified as potential promoters of healthy child development. This observational study of 200 family mealtimes examined the relation between child health indicators in a group of children with persistent asthma and three dimensions of mealtime interaction: Action, Behavior Control, and Communication. Mealtimes lasted, on average, 18 minutes with a range of 2 to 47. Percent of time spent in Action and Positive Communication varied by asthma symptom severity ...

  7. Lessons from the unexpected: the importance of data infrastructure, conceptual models, and serendipity in health services research.

    Science.gov (United States)

    Mechanic, D

    2001-01-01

    In examining the importance of data systems, conceptual models, and serendipity in understanding health services, the case is made for a vigorous and responsive data infrastructure and more emphasis on conceptual development. Particularly important is the development of data systems that can keep pace with changes in health care organization and patterns of care. Three examples--from managed care, deinstitutionalization, and physician remuneration--demonstrate the need to empirically examine seemingly obvious assumptions about health patterns and trends, and the lessons to be learned when assumptions are proved incorrect. Major future challenges include incorporating patient preferences into outcomes research, meaningful communication about treatment options and health plan choices, and understanding how organizational culture and norms affect decision processes.

  8. Observing and modelling phytoplankton community structure in the North Sea

    Science.gov (United States)

    Ford, David A.; van der Molen, Johan; Hyder, Kieran; Bacon, John; Barciela, Rosa; Creach, Veronique; McEwan, Robert; Ruardij, Piet; Forster, Rodney

    2017-03-01

    Phytoplankton form the base of the marine food chain, and knowledge of phytoplankton community structure is fundamental when assessing marine biodiversity. Policy makers and other users require information on marine biodiversity and other aspects of the marine environment for the North Sea, a highly productive European shelf sea. This information must come from a combination of observations and models, but currently the coastal ocean is greatly under-sampled for phytoplankton data, and outputs of phytoplankton community structure from models are therefore not yet frequently validated. This study presents a novel set of in situ observations of phytoplankton community structure for the North Sea using accessory pigment analysis. The observations allow a good understanding of the patterns of surface phytoplankton biomass and community structure in the North Sea for the observed months of August 2010 and 2011. Two physical-biogeochemical ocean models, the biogeochemical components of which are different variants of the widely used European Regional Seas Ecosystem Model (ERSEM), were then validated against these and other observations. Both models were a good match for sea surface temperature observations, and a reasonable match for remotely sensed ocean colour observations. However, the two models displayed very different phytoplankton community structures, with one better matching the in situ observations than the other. Nonetheless, both models shared some similarities with the observations in terms of spatial features and inter-annual variability. An initial comparison of the formulations and parameterizations of the two models suggests that diversity between the parameter settings of model phytoplankton functional types, along with formulations which promote a greater sensitivity to changes in light and nutrients, is key to capturing the observed phytoplankton community structure. These findings will help inform future model development, which should be coupled

  9. Is the island universe model consistent with observations?

    OpenAIRE

    Piao, Yun-Song

    2005-01-01

    We study the island universe model, in which initially the universe is in a cosmological constant sea, then the local quantum fluctuations violating the null energy condition create the islands of matter, some of which might corresponds to our observable universe. We examine the possibility that the island universe model is regarded as an alternative scenario of the origin of observable universe.

  10. Bayesian network modeling applied to coastal geomorphology: lessons learned from a decade of experimentation and application

    Science.gov (United States)

    Plant, N. G.; Thieler, E. R.; Gutierrez, B.; Lentz, E. E.; Zeigler, S. L.; Van Dongeren, A.; Fienen, M. N.

    2016-12-01

    We evaluate the strengths and weaknesses of Bayesian networks that have been used to address scientific and decision-support questions related to coastal geomorphology. We will provide an overview of coastal geomorphology research that has used Bayesian networks and describe what this approach can do and when it works (or fails to work). Over the past decade, Bayesian networks have been formulated to analyze the multi-variate structure and evolution of coastal morphology and associated human and ecological impacts. The approach relates observable system variables to each other by estimating discrete correlations. The resulting Bayesian-networks make predictions that propagate errors, conduct inference via Bayes rule, or both. In scientific applications, the model results are useful for hypothesis testing, using confidence estimates to gage the strength of tests while applications to coastal resource management are aimed at decision-support, where the probabilities of desired ecosystems outcomes are evaluated. The range of Bayesian-network applications to coastal morphology includes emulation of high-resolution wave transformation models to make oceanographic predictions, morphologic response to storms and/or sea-level rise, groundwater response to sea-level rise and morphologic variability, habitat suitability for endangered species, and assessment of monetary or human-life risk associated with storms. All of these examples are based on vast observational data sets, numerical model output, or both. We will discuss the progression of our experiments, which has included testing whether the Bayesian-network approach can be implemented and is appropriate for addressing basic and applied scientific problems and evaluating the hindcast and forecast skill of these implementations. We will present and discuss calibration/validation tests that are used to assess the robustness of Bayesian-network models and we will compare these results to tests of other models. This will

  11. Observational evidence for various models of Moving Magnetic Features

    Science.gov (United States)

    Lee, Jeongwoo W.

    1992-01-01

    New measurements of Moving Magnetic Features (MMFs) based on the observations of the active region NOAA 5612 made at Big Bear Solar Observatory (BBSO) on August 2, 1989 are presented. The existing theoretical models are checked against the new observations, and the origin of MMFs conjectured from the deduced observational constraints is discussed.

  12. Testing models of triggered star formation: theory and observation

    CERN Document Server

    Haworth, Thomas J; Acreman, David M

    2012-01-01

    One of the main reasons that triggered star formation is contentious is the failure to accurately link the observations with models in a detailed, quantitative, way. It is therefore critical to continuously test and improve the model details and methods with which comparisons to observations are made. We use a Monte Carlo radiation transport and hydrodynamics code TORUS to show that the diffuse radiation field has a significant impact on the outcome of radiatively driven implosion (RDI) models. We also calculate SEDs and synthetic images from the models to test observational diagnostics that are used to determine bright rimmed cloud conditions and search for signs of RDI.

  13. Holonomy observables in Ponzano-Regge type state sum models

    CERN Document Server

    Barrett, John W

    2011-01-01

    We study observables on group elements in the Ponzano-Regge model. We show that these observables have a natural interpretation in terms of Feynman diagrams on a sphere and contrast them to the well studied observables on the spin labels. We elucidate this interpretation by showing how they arise from the no-gravity limit of the Turaev-Viro model and Chern-Simons theory.

  14. Lessons from making the Structural Classification of Proteins (SCOP) and their implications for protein structure modelling.

    Science.gov (United States)

    Andreeva, Antonina

    2016-06-15

    The Structural Classification of Proteins (SCOP) database has facilitated the development of many tools and algorithms and it has been successfully used in protein structure prediction and large-scale genome annotations. During the development of SCOP, numerous exceptions were found to topological rules, along with complex evolutionary scenarios and peculiarities in proteins including the ability to fold into alternative structures. This article reviews cases of structural variations observed for individual proteins and among groups of homologues, knowledge of which is essential for protein structure modelling.

  15. Fuzzy model-based observers for fault detection in CSTR.

    Science.gov (United States)

    Ballesteros-Moncada, Hazael; Herrera-López, Enrique J; Anzurez-Marín, Juan

    2015-11-01

    Under the vast variety of fuzzy model-based observers reported in the literature, what would be the properone to be used for fault detection in a class of chemical reactor? In this study four fuzzy model-based observers for sensor fault detection of a Continuous Stirred Tank Reactor were designed and compared. The designs include (i) a Luenberger fuzzy observer, (ii) a Luenberger fuzzy observer with sliding modes, (iii) a Walcott-Zak fuzzy observer, and (iv) an Utkin fuzzy observer. A negative, an oscillating fault signal, and a bounded random noise signal with a maximum value of ±0.4 were used to evaluate and compare the performance of the fuzzy observers. The Utkin fuzzy observer showed the best performance under the tested conditions.

  16. Modeling of the 2011 Japan Tsunami: Lessons for Near-Field Forecast

    Science.gov (United States)

    Wei, Yong; Chamberlin, Christopher; Titov, Vasily V.; Tang, Liujuan; Bernard, Eddie N.

    2013-06-01

    During the devastating 11 March 2011 Japanese tsunami, data from two tsunami detectors were used to determine the tsunami source within 1.5 h of earthquake origin time. For the first time, multiple near-field tsunami measurements of the 2011 Japanese tsunami were used to demonstrate the accuracy of the National Oceanic and Atmospheric Administration (NOAA) real-time flooding forecast system in the far field. To test the accuracy of the same forecast system in the near field, a total of 11 numerical models with grids telescoped to 2 arcsec (~60 m) were developed to hindcast the propagation and coastal inundation of the 2011 Japanese tsunami along the entire east coastline of Japan. Using the NOAA tsunami source computed in near real-time, the model results of tsunami propagation are validated with tsunami time series measured at different water depths offshore and near shore along Japan's coastline. The computed tsunami runup height and spatial distribution are highly consistent with post-tsunami survey data collected along the Japanese coastline. The computed inundation penetration also agrees well with survey data, giving a modeling accuracy of 85.5 % for the inundation areas along 800 km of coastline between Ibaraki Prefecture (north of Kashima) and Aomori Prefecture (south of Rokkasho). The inundation model results highlighted the variability of tsunami impact in response to different offshore bathymetry and flooded terrain. Comparison of tsunami sources inferred from different indirect methods shows the crucial importance of deep-ocean tsunami measurements for real-time tsunami forecasts. The agreement between model results and observations along Japan's coastline demonstrate the ability and potential of NOAA's methodology for real-time near-field tsunami flooding forecasts. An accurate tsunami flooding forecast within 30 min may now be possible using the NOAA forecast methodology with carefully placed tsunameters and large-scale high-resolution inundation

  17. Modelling the fate of marine debris along a complex shoreline: Lessons from the Great Barrier Reef

    Science.gov (United States)

    Critchell, K.; Grech, A.; Schlaefer, J.; Andutta, F. P.; Lambrechts, J.; Wolanski, E.; Hamann, M.

    2015-12-01

    The accumulation of floating anthropogenic debris in marine and coastal areas has environmental, economic, aesthetic, and human health impacts. Until now, modelling the transport of such debris has largely been restricted to the large-scales of open seas. We used oceanographic modelling to identify potential sites of debris accumulation along a rugged coastline with headlands, islands, rocky coasts and beaches. Our study site was the Great Barrier Reef World Heritage Area that has an emerging problem with debris accumulation. We found that the classical techniques of modelling the transport of floating debris models are only moderately successful due to a number of unknowns or assumptions, such as the value of the wind drift coefficient, the variability of the oceanic forcing and of the wind, the resuspension of some floating debris by waves, and the poorly known relative contribution of floating debris from urban rivers and commercial and recreational shipping. Nevertheless the model was successful in reproducing a number of observations such as the existence of hot spots of accumulation. The orientation of beaches to the prevailing wind direction affected the accumulation rate of debris. The wind drift coefficient and the exact timing of the release of the debris at sea affected little the movement of debris originating from rivers but it affected measurably that of debris originating from ships. It was thus possible to produce local hotspot maps for floating debris, especially those originating from rivers. Such modelling can be used to inform local management decisions, and it also identifies likely priority research areas to more reliably predict the trajectory and landing points of floating debris.

  18. WDAC Task Team on Observations for Model Evaluation: Facilitating the use of observations for CMIP

    Science.gov (United States)

    Waliser, D. E.; Gleckler, P. J.; Ferraro, R.; Eyring, V.; Bosilovich, M. G.; Schulz, J.; Thepaut, J. N.; Taylor, K. E.; Chepfer, H.; Bony, S.; Lee, T. J.; Joseph, R.; Mathieu, P. P.; Saunders, R.

    2015-12-01

    Observations are essential for the development and evaluation of climate models. Satellite and in-situ measurements as well as reanalysis products provide crucial resources for these purposes. Over the last two decades, the climate modeling community has become adept at developing model intercomparison projects (MIPs) that provide the basis for more systematic comparisons of climate models under common experimental conditions. A prominent example among these is the coupled MIP (CMIP). Due to its growing importance in providing input to the IPCC, the framework for CMIP, now planning CMIP6, has expanded to include a very comprehensive and precise set of experimental protocols, with an advanced data archive and dissemination system. While the number, types and sophistication of observations over the same time period have kept pace, their systematic application to the evaluation of climate models has yet to be fully exploited due to a lack of coordinated protocols for identifying, archiving, documenting and applying observational resources. This presentation will discuss activities and plans of the World Climate Research Program (WCRP) Data Advisory Council's (WDAC) Task Team on Observations for Model Evaluation for facilitating the use of observations for model evaluation. The presentation will include an update on the status of the obs4MIPs and ana4MIPs projects, whose purpose is to provide a limited collection of well-established and documented observation and reanalysis datasets for comparison with Earth system models, targeting CMIP in particular. The presentation will also describe the role these activities and datasets play in the development of a set of community standard observation-based climate model performance metrics by the Working Group on Numerical Experimentation (WGNE)'s Performance Metrics Panel, as well as which CMIP6 experiments these activities are targeting, and where additional community input and contributions to these activities are needed.

  19. Predicting the future completing models of observed complex systems

    CERN Document Server

    Abarbanel, Henry

    2013-01-01

    Predicting the Future: Completing Models of Observed Complex Systems provides a general framework for the discussion of model building and validation across a broad spectrum of disciplines. This is accomplished through the development of an exact path integral for use in transferring information from observations to a model of the observed system. Through many illustrative examples drawn from models in neuroscience, fluid dynamics, geosciences, and nonlinear electrical circuits, the concepts are exemplified in detail. Practical numerical methods for approximate evaluations of the path integral are explored, and their use in designing experiments and determining a model's consistency with observations is investigated. Using highly instructive examples, the problems of data assimilation and the means to treat them are clearly illustrated. This book will be useful for students and practitioners of physics, neuroscience, regulatory networks, meteorology and climate science, network dynamics, fluid dynamics, and o...

  20. Correcting biased observation model error in data assimilation

    CERN Document Server

    Harlim, John

    2016-01-01

    While the formulation of most data assimilation schemes assumes an unbiased observation model error, in real applications, model error with nontrivial biases is unavoidable. A practical example is the error in the radiative transfer model (which is used to assimilate satellite measurements) in the presence of clouds. As a consequence, many (in fact 99\\%) of the cloudy observed measurements are not being used although they may contain useful information. This paper presents a novel nonparametric Bayesian scheme which is able to learn the observation model error distribution and correct the bias in incoming observations. This scheme can be used in tandem with any data assimilation forecasting system. The proposed model error estimator uses nonparametric likelihood functions constructed with data-driven basis functions based on the theory of kernel embeddings of conditional distributions developed in the machine learning community. Numerically, we show positive results with two examples. The first example is des...

  1. Mars Rover Model Celebration: Developing Inquiry Based Lesson Plans to Teach Planetary Science In Elementary And Middle School

    Science.gov (United States)

    Bering, E. A.; Slagle, E.; Nieser, K.; Carlson, C.; Kapral, A.; Dominey, W.; Ramsey, J.; Konstantinidis, I.; James, J.; Sweaney, S.; Mendez, R.

    2012-12-01

    The recent NASA Mars Rover missions capture the imagination of children, as NASA missions have done for decades. The University of Houston is in the process of developing a prototype of a flexible program that offers children an in-depth educational experience culminating in the design and construction of their own model rover. The existing prototype program is called the Mars Rover Model Celebration. It focuses on students, teachers and parents in grades 3-8. Students will design and build a model of a Mars rover to carry out a student selected science mission on the surface of Mars. The model will be a mock-up, constructed at a minimal cost from art supplies. The students will build the models as part of a project on Mars. The students will be given design criteria for a rover and will do basic research on Mars that will determine the objectives and features of their rover. This project may be used either informally as an after school club or youth group activity or formally as part of a class studying general science, earth science, solar system astronomy or robotics, or as a multi-disciplinary unit for a gifted and talented program. The project's unique strength lies in engaging students in the process of spacecraft design and interesting them in aerospace engineering careers. The project is aimed at elementary and secondary education. Not only will these students learn about scientific fields relevant to the mission (space science, physics, geology, robotics, and more), they will gain an appreciation for how this knowledge is used to tackle complex problems. The low cost of the event makes it an ideal enrichment vehicle for low income schools. It provides activities that provide professional development to educators, curricular support resources using NASA Science Mission Directorate (SMD) content, and provides family opportunities for involvement in K-12 student learning. This paper will describe the development of a detailed set of new 5E lesson plans to

  2. What sea-ice biogeochemical modellers need from observers

    Directory of Open Access Journals (Sweden)

    Nadja Steiner

    2016-02-01

    Full Text Available Abstract Numerical models can be a powerful tool helping to understand the role biogeochemical processes play in local and global systems and how this role may be altered in a changing climate. With respect to sea-ice biogeochemical models, our knowledge is severely limited by our poor confidence in numerical model parameterisations representing those processes. Improving model parameterisations requires communication between observers and modellers to guide model development and improve the acquisition and presentation of observations. In addition to more observations, modellers need conceptual and quantitative descriptions of the processes controlling, for example: primary production and diversity of algal functional types in sea ice, ice algal growth, release from sea ice, heterotrophic remineralisation, transfer and emission of gases (e.g., DMS, CH4, BrO, incorporation of seawater components in growing sea ice (including Fe, organic and inorganic carbon, and major salts and subsequent release; CO2 dynamics (including CaCO3 precipitation, flushing and supply of nutrients to sea-ice ecosystems; and radiative transfer through sea ice. These issues can be addressed by focused observations, as well as controlled laboratory and field experiments that target specific processes. The guidelines provided here should help modellers and observers improve the integration of measurements and modelling efforts and advance toward the common goal of understanding biogeochemical processes in sea ice and their current and future impacts on environmental systems.

  3. T-wave alternans: lessons learned from a biophysical ECG model.

    Science.gov (United States)

    Sassi, Roberto; Mainardi, Luca T

    2012-01-01

    T-wave alternans (TWA) is an alteration of the ECG T-wave which repeats every other beat. An alternating pattern has been also observed at myocytes level, involving both action potential duration and morphology (mainly in phases 2 and 3). While this might happen in a specific region (i.e., myocardial ischemia), it can also involve the entire myocardium. It is still unclear how alternations at the myocytes level are reflected on surface ECG modification of T-waves, especially when in vivo human hearts are considered. We have recently proposed a simple stochastic model of ventricular repolarization (IEEE Trans. Biomed. Eng., 2011), which takes into account both repolarization heterogeneity across the myocardium as well as random beat-to-beat variations in cells' activity. In this work, we generalized that model incorporating a term which describes myocytes alternans related to T-wave variability. Starting from the model and using the electrophysiological formulation developed by van Oosterom, we derived an analytical formula relating surface ECG to variations at the myocytes' level. Several theoretical results were then obtained. First, temporal small random variations in repolarization heterogeneity affect the precision of TWA estimates in a significant way. Second, TWA theoretically differs across leads, but multilead configuration can be used to reduce the effect of noise. Finally, the dependency between TWA and T-wave amplitude was analyzed.

  4. Thermal Infrared Observations and Thermophysical Modeling of Phobos

    Science.gov (United States)

    Smith, Nathan Michael; Edwards, Christopher Scott; Mommert, Michael; Trilling, David E.; Glotch, Timothy

    2016-10-01

    Mars-observing spacecraft have the opportunity to study Phobos from Mars orbit, and have produced a sizeable record of observations using the same instruments that study the surface of the planet below. However, these observations are generally infrequent, acquired only rarely over each mission.Using observations gathered by Mars Global Surveyor's (MGS) Thermal Emission Spectrometer (TES), we can investigate the fine layer of regolith that blankets Phobos' surface, and characterize its thermal properties. The mapping of TES observations to footprints on the Phobos surface has not previously been undertaken, and must consider the orientation and position of both MGS and Phobos, and TES's pointing mirror angle. Approximately 300 fully resolved observations are available covering a significant subset of Phobos' surface at a variety of scales.The properties of the surface regolith, such as grain size, density, and conductivity, determine how heat is absorbed, transferred, and reradiated to space. Thermophysical modeling allows us to simulate these processes and predict, for a given set of assumed parameters, how the observed thermal infrared spectra will appear. By comparing models to observations, we can constrain the properties of the regolith, and see how these properties vary with depth, as well as regionally across the Phobos surface. These constraints are key to understanding how Phobos formed and evolved over time, which in turn will help inform the environment and processes that shaped the solar system as a whole.We have developed a thermophysical model of Phobos adapted from a model used for unresolved observations of asteroids. The model has been modified to integrate thermal infrared flux across each observed portion of Phobos. It will include the effects of surface roughness, temperature-dependent conductivity, as well as radiation scattered, reflected, and thermally emitted from the Martian surface. Combining this model with the newly-mapped TES

  5. Observational semantics of the Prolog Resolution Box Model

    CERN Document Server

    Deransart, Pierre; Ferrand, Gérard

    2007-01-01

    This paper specifies an observational semantics and gives an original presentation of the Byrd box model. The approach accounts for the semantics of Prolog tracers independently of a particular Prolog implementation. Prolog traces are, in general, considered as rather obscure and difficult to use. The proposed formal presentation of its trace constitutes a simple and pedagogical approach for teaching Prolog or for implementing Prolog tracers. It is a form of declarative specification for the tracers. The trace model introduced here is only one example to illustrate general problems relating to tracers and observing processes. Observing processes know, from observed processes, only their traces. The issue is then to be able to reconstitute, by the sole analysis of the trace, part of the behaviour of the observed process, and if possible, without any loss of information. As a matter of fact, our approach highlights qualities of the Prolog resolution box model which made its success, but also its insufficiencies...

  6. Technical Note: Calibration and validation of geophysical observation models

    NARCIS (Netherlands)

    Salama, M.S.; van der Velde, R.; van der Woerd, H.J.; Kromkamp, J.C.; Philippart, C.J.M.; Joseph, A.T.; O'Neill, P.E.; Lang, R.H.; Gish, T.; Werdell, P.J.; Su, Z.

    2012-01-01

    We present a method to calibrate and validate observational models that interrelate remotely sensed energy fluxes to geophysical variables of land and water surfaces. Coincident sets of remote sensing observation of visible and microwave radiations and geophysical data are assembled and subdivided i

  7. Time-symmetric universe model and its observational implication

    Energy Technology Data Exchange (ETDEWEB)

    Futamase, T.; Matsuda, T.

    1987-08-01

    A time-symmetric closed-universe model is discussed in terms of the radiation arrow of time. The time symmetry requires the occurrence of advanced waves in the recontracting phase of the Universe. We consider the observational consequences of such advanced waves, and it is shown that a test observer in the expanding phase can observe a time-reversed image of a source of radiation in the future recontracting phase.

  8. The detection of observations possibly influential for model selection

    NARCIS (Netherlands)

    Ph.H.B.F. Franses (Philip Hans)

    1991-01-01

    textabstractModel selection can involve several variables and selection criteria. A simple method to detect observations possibly influential for model selection is proposed. The potentials of this method are illustrated with three examples, each of which is taken from related studies.

  9. Model-independent inference on compact-binary observations

    Science.gov (United States)

    Mandel, Ilya; Farr, Will M.; Colonna, Andrea; Stevenson, Simon; Tiňo, Peter; Veitch, John

    2017-03-01

    The recent advanced LIGO detections of gravitational waves from merging binary black holes enhance the prospect of exploring binary evolution via gravitational-wave observations of a population of compact-object binaries. In the face of uncertainty about binary formation models, model-independent inference provides an appealing alternative to comparisons between observed and modelled populations. We describe a procedure for clustering in the multidimensional parameter space of observations that are subject to significant measurement errors. We apply this procedure to a mock data set of population-synthesis predictions for the masses of merging compact binaries convolved with realistic measurement uncertainties, and demonstrate that we can accurately distinguish subpopulations of binary neutron stars, binary black holes, and mixed neutron star-black hole binaries with tens of observations.

  10. Web-based Services for Earth Observing and Model Data in National Applications and Hazards

    Science.gov (United States)

    Kafatos, M.; Boybeyi, Z.; Cervone, G.; di, L.; Sun, D.; Yang, C.; Yang, R.

    2005-12-01

    The ever-growing large volumes of Earth system science data, collected by Earth observing platforms, in situ stations and as model output data, are increasingly being used by discipline scientists and by wider classes of users. In particular, applications of Earth system science data to environmental and hazards as well as other national applications, require tailored or specialized data, as well as web-based tools and infrastructure. The latter are driven by applications and usage drivers which include ease of access, visualization of complex data, ease of producing value-added data, GIS and open source analysis usage, metadata, etc. Here we present different aspects of such web-based services and access, and discuss several applications in the hazards and environmental areas, including earthquake signatures and observations and model runs of hurricanes. Examples and lessons learned from the consortium Mid-Atlantic Geospatial Information Consortium will be presented. We discuss a NASA-funded, open source on-line data analysis system that is being applied to climate studies for the ESIP Federation. Since enhanced, this project and the next-generation Metadata Integrated Data Analysis System allow users not only to identify data but also to generate new data products on-the-fly. The functionalities extend from limited predefined functions, to sophisticated functions described by general-purposed GrADS (Grid Analysis and Display System) commands. The Federation system also allows third party data products to be combined with local data. Software component are available for converting the output from MIDAS (OPenDAP) into OGC compatible software. The on-going Grid efforts at CEOSR and LAITS in the School of Computational Sciences (SCS) include enhancing the functions of Globus to provide support for a geospatial system so the system can share the computing power to handle problems with different peak access times and improve the stability and flexibility of a rapid

  11. Hints on halo evolution in SFDM models with galaxy observations

    CERN Document Server

    Gonzalez-Morales, Alma X; Urena-Lopez, L Arturo; Valenzuela, Octavio

    2012-01-01

    A massive, self-interacting scalar field has been considered as a possible candidate for the dark matter in the universe. We present an observational constraint to the model arising from strong lensing observations in galaxies. The result points to a discrepancy in the properties of scalar field dark matter halos for dwarf and lens galaxies, mainly because halo parameters are directly related to physical quantities in the model. This is an important indication that it becomes necessary to have a better understanding of halo evolution in scalar field dark matter models, where the presence of baryons can play an important role.

  12. Observational Constraints on a Variable Dark Energy Model

    CERN Document Server

    Movahed, M S; Movahed, Mohammad Sadegh; Rahvar, Sohrab

    2006-01-01

    We present cosmological tests for a phenomenological parametrization of quintessence model with time-varying equation of state on low, intermediate and high redshift observations \\cite{w04}. We study the sensitivity of the comoving distance and volume element with the Alcock-Paczynski test to the time varying model of dark energy. At the intermediate redshifts, Gold supernova Type Ia data is used to fit the quintessence model to the observed distance modulus. The value of the observed acoustic angular scale by WMAP experiment also is compared with the model. The combined result of CMB and SNIa data confines $w=p/\\rho$ to be more than -1.3 which can violate the dominant energy condition.

  13. The Canterbury Tales: Lessons from the Canterbury Earthquake Sequence to Inform Better Public Communication Models

    Science.gov (United States)

    McBride, S.; Tilley, E. N.; Johnston, D. M.; Becker, J.; Orchiston, C.

    2015-12-01

    This research evaluates the public education earthquake information prior to the Canterbury Earthquake sequence (2010-present), and examines communication learnings to create recommendations for improvement in implementation for these types of campaigns in future. The research comes from a practitioner perspective of someone who worked on these campaigns in Canterbury prior to the Earthquake Sequence and who also was the Public Information Manager Second in Command during the earthquake response in February 2011. Documents, specifically those addressing seismic risk, that were created prior to the earthquake sequence, were analyzed, using a "best practice matrix" created by the researcher, for how closely these aligned to best practice academic research. Readability tests and word counts are also employed to assist with triangulation of the data as was practitioner involvement. This research also outlines the lessons learned by practitioners and explores their experiences in regards to creating these materials and how they perceive these now, given all that has happened since the inception of the booklets. The findings from the research showed these documents lacked many of the attributes of best practice. The overly long, jargon filled text had little positive outcome expectancy messages. This probably would have failed to persuade anyone that earthquakes were a real threat in Canterbury. Paradoxically, it is likely these booklets may have created fatalism in publics who read the booklets. While the overall intention was positive, for scientists to explain earthquakes, tsunami, landslides and other risks to encourage the public to prepare for these events, the implementation could be greatly improved. This final component of the research highlights points of improvement for implementation for more successful campaigns in future. The importance of preparedness and science information campaigns can be not only in preparing the population but also into development of

  14. Modelling of an explosive event observed by SUMER & TRACE

    Science.gov (United States)

    Price, Daniel; Taroyan, Youra; Ishak, Bebe

    2016-07-01

    To fully understand coronal heating, we must first understand the different solar processes that move energy throughout the solar atmosphere. TRACE observations have revealed a short cold loop evolving over a small timescale, seemingly with multiple explosive events occurring along its length. An adaptive hydrodynamic radiation code was used to simulate the loop under non-equilibrium ionization. Footpoint heating and cold plasma injection were considered as possible scenarios to reproduce the observations. The simulation results were converted into synthetic observations through forward modelling, for comparison to SOHO/SUMER spectral observations of the loop.

  15. How useful are stream level observations for model calibration?

    Science.gov (United States)

    Seibert, Jan; Vis, Marc; Pool, Sandra

    2014-05-01

    Streamflow estimation in ungauged basins is especially challenging in data-scarce regions and it might be reasonable to take at least a few measurements. Recent studies demonstrated that few streamflow measurements, representing data that could be measured with limited efforts in an ungauged basin, might be needed to constrain runoff models for simulations in ungauged basins. While in these previous studies we assumed that few streamflow measurements were taken during different points in time over one year, obviously it would be reasonable to (also) measure stream levels. Several approaches could be used in practice for such stream level observations: water level loggers have become less expensive and easier to install and can be used to obtain continuous stream level time series; stream levels will in the near future be increasingly available from satellite remote sensing resulting in evenly space time series; community-based approaches (e.g., crowdhydrology.org), finally, can offer level observations at irregular time intervals. Here we present a study where a catchment runoff model (the HBV model) was calibrated for gauged basins in Switzerland assuming that only a subset of the data was available. We pretended that only stream level observations at different time intervals, representing the temporal resolution of the different observation approaches mentioned before, and a small number of streamflow observations were available. The model, which was calibrated based on these data subsets, was then evaluated on the full observed streamflow record. Our results indicate that streamlevel data alone already can provide surprisingly good model simulation results, which can be further improved by the combination with one streamflow observation. The surprisingly good results with only streamlevel time series can be explained by the relatively high precipitation in the studied catchments. Constructing a hypothetical catchment with reduced precipitation resulted in poorer

  16. Used of observed snow in the Snomod model

    Science.gov (United States)

    Sorteberg, H. K.

    2009-04-01

    For the hydroelectric industry in Norway, it is important to know exactly what resources are available at all times. The correct volume of snow reserves and the accurate forecasting of the spring flood volume can provide the best basis for maximising production values. The forward market can fluctuate considerably, and it is therefore important to know what is available at the right time. For many years, the Snomod model has been used to calculate snow reserves and to forecast the spring flood volume. Snomod is based on a regression equation between the annual observations of inflow and one or more precipitation series. Manual snow measurements are used in both Snomod and the HBV model and other models to estimate the correct snow reserves. In operational use, Snomod is updated manually with the snow estimate that is considered to be correct. Following the winter of 2007-2008, analyses were carried out to determine how accurate the forecasting was. The analyses were based on comparing the spring flood volume forecast with the observed spring flood volume using the ‘observed precipitation' precipitation scenario. Such analyses can tell us something about the quality of the model results for this winter. Analyses have been carried out for 18 models using Snomod. When the results from the analyses are compared with the spring floods, the spring flood volume has been forecast accurately for most of the models with observed precipitation when observed snow has been used in the forecasting process. The results indicate that nine of the models are very good, five are good and two are reasonable. Only one model produced a poor forecast of the spring flood volume. If a corresponding analysis without correction for observed snow is carried out, and the observed spring flood is compared with the forecast spring flood, the results are not as good. This may stem from the fact that during the spring of 2008 there were higher levels of evaporation during the melting season than

  17. The role of observational uncertainties in testing model hypotheses

    Science.gov (United States)

    Westerberg, I. K.; Birkel, C.

    2012-12-01

    Knowledge about hydrological processes and the spatial and temporal distribution of water resources is needed as a basis for managing water for hydropower, agriculture and flood-protection. Conceptual hydrological models may be used to infer knowledge on catchment functioning but are affected by uncertainties in the model representation of reality as well as in the observational data used to drive the model and to evaluate model performance. Therefore, meaningful hypothesis testing of the hydrological functioning of a catchment requires such uncertainties to be carefully estimated and accounted for in model calibration and evaluation. The aim of this study was to investigate the role of observational uncertainties in hypothesis testing, in particular whether it was possible to detect model-structural representations that were wrong in an important way given the uncertainties in the observational data. We studied the relatively data-scarce tropical Sarapiqui catchment in Costa Rica, Central America, where water resources play a vital part for hydropower production and livelihood. We tested several model structures of varying complexity as hypotheses about catchment functioning, but also hypotheses about the nature of the modelling errors. The tests were made within a learning framework for uncertainty estimation which enabled insights into data uncertainties, suitable model-structural representations and appropriate likelihoods. The observational uncertainty in discharge data was estimated from a rating-curve analysis and precipitation measurement errors through scenarios relating the error to, for example, canopy interception, wind-driven rain and the elevation gradient. The hypotheses were evaluated in a posterior analysis of the simulations where the performance of each simulation was analysed relative to the observational uncertainties for the entire hydrograph as well as for different aspects of the hydrograph (e.g. peak flows, recession periods, and base flow

  18. Testing ocean tide models using GGP superconducting gravimeter observations

    Science.gov (United States)

    Baker, T.; Bos, M.

    2003-04-01

    Observations from the global network of superconducting gravimeters in the Global Geodynamics Project (GGP) are used to test 10 ocean tide models (SCHW; FES94.1, 95.2, 98, 99; CSR3.0, 4.0; TPXO.5; GOT99.2b; and NAO.99b). In addition, observations are used from selected sites with LaCoste and Romberg gravimeters with electrostatic feedback, where special attention has been given to achieving a calibration accuracy of 0.1%. In Europe, there are several superconducting gravimeter stations in a relatively small area and this can be used to advantage in testing the ocean (and body) tide models and in identifying sites with anomalous observations. At some of the superconducting gravimeter sites there are anomalies in the in-phase components of the main tidal harmonics, which are due to calibration errors of up to 0.3%. It is shown that the recent ocean tide models are in better agreement with the tidal gravity observations than were the earlier models of Schwiderski and FES94.1. However, no single ocean tide model gives completely satisfactory results in all areas of the world. For example, for M2 the TPXO.5 and NAO99b models give anomalous results in Europe, whereas the FES95.2, FES98 and FES99 models give anomalous results in China and Japan. It is shown that the observations from this improved set of tidal gravity stations will provide an important test of the new ocean tide models that will be developed in the next few years. For further details see Baker, T.F. and Bos, M.S. (2003). "Validating Earth and ocean tide models using tidal gravity measurements", Geophysical Journal International, 152.

  19. Enhancing mathematics teachers' quality through Lesson Study.

    Science.gov (United States)

    Lomibao, Laila S

    2016-01-01

    The efficiency and effectivity of the learning experience is dependent on the teacher quality, thus, enhancing teacher's quality is vital in improving the students learning outcome. Since, the usual top-down one-shot cascading model practice for teachers' professional development in Philippines has been observed to have much information dilution, and the Southeast Asian Ministers of Education Organization demanded the need to develop mathematics teachers' quality standards through the Southeast Asia Regional Standards for Mathematics Teachers (SEARS-MT), thus, an intensive, ongoing professional development model should be provided to teachers. This study was undertaken to determine the impact of Lesson Study on Bulua National High School mathematics teachers' quality level in terms of SEARS-MT dimensions. A mixed method of quantitative-qualitative research design was employed. Results of the analysis revealed that Lesson Study effectively enhanced mathematics teachers' quality and promoted teachers professional development. Teachers positively perceived Lesson Study to be beneficial for them to become a better mathematics teacher.

  20. Modeling Hydrologic Transport through the Critical Zone: Lessons from Catchment-Scale and Lysimeter Studies

    Science.gov (United States)

    Benettin, P.; Queloz, P.; Bailey, S. W.; McGuire, K. J.; Rinaldo, A.; Botter, G.

    2015-12-01

    Water age distributions can be used to address a number of environmental challenges, such as modeling the dynamics of river water quality, quantifying the interactions between shallow and deep flow systems and understanding nutrient loading persistence. Moreover, as the travel time of a water particle is the time available for biogeochemical reactions, it can be explicitly used to predict the concentration of non-conservative solutes, as e.g. those derived by mineral weathering. In recent years, many studies acknowledged the dynamic nature of streamflow age and linked it to observed variations in stream water quality. In this new framework, water stored within a catchment can be seen as a pool that is selectively "sampled" by streams and vegetation, determining the chemical composition of discharge and evapotranspiration. We present results from a controlled lysimeter experiment and real-world catchments, where the theoretical framework has been used to reproduce water quality datasets including conservative tracers (e.g. chloride and water stable isotopes) and weathering-derived solutes (like silicon and sodium). The approach proves useful to estimate the catchment water storage involved in solute mixing and sheds light on how solutes and water of different ages are selectively removed by vegetation and soil drainage.

  1. Total cloud cover from satellite observations and climate models

    Directory of Open Access Journals (Sweden)

    P. Probst

    2010-09-01

    Full Text Available Global and zonal monthly means of cloud cover fraction for total cloudiness (CF from the ISCCP D2 dataset are compared to same quantity produced by the 20th century simulations of 21 climate models from the World Climate Research Programme's (WCRP's Coupled Model Intercomparison Project phase 3 (CMIP3 multi-model dataset archived by the Program for Climate Model Diagnosis and Intercomparison (PCMDI. The comparison spans the time frame from January 1984 to December 1999 and the global and zonal average of CF are studied. The restriction to total cloudiness depends on the output of some models that does not include the 3D cloud structure. It is shown that the global mean of CF for the PCMDI/CMIP3 models, averaged over the whole period, exhibits a considerable variance and generally underestimates the ISCCP value. Very large discrepancies among models, and between models and observations, are found in the polar areas, where both models and satellite observations are less reliable, and especially near Antarctica. For this reason the zonal analysis is focused over the 60° S–60° N latitudinal belt, which includes the tropical area and mid latitudes. The two hemispheres are analyzed separately to show the variation of the amplitude of the seasonal cycle. Most models overestimate the yearly averaged values of CF over all of the analysed areas, while differences emerge in their ability to capture the amplitude of the seasonal cycle. The models represent, in a qualitatively correct way, the magnitude and the weak sign of the seasonal cycle over the whole geographical domain, but overestimate the strength of the signal in the tropical areas and at mid-latitudes, when taken separately. The interannual variability of the two yearly averages and of the amplitude of the seasonal cycle is greatly underestimated by all models in each area analysed. This work shows that the climate models have an heterogeneous behaviour in simulating the CF over

  2. The Szekeres Swiss Cheese model and the CMB observations

    CERN Document Server

    Bolejko, Krzysztof

    2008-01-01

    This paper presents the application of the Szekeres Swiss Cheese model to observations of the cosmic microwave background (CMB) radiation. It aims to study the CMB temperature fluctuations by the means of the exact inhomogeneous Szekeres model. So far the impact of inhomogeneous matter distribution on the CMB observations has been almost exclusively studied within the linear perturbations of the Friedmann model. However, since the density contrast of cosmic structures is larger than 1 this issue is worth studying using another approach. The Szekeres model is an inhomogeneous, non-symmetrical and exact solution of the Einstein equations. In this model, light propagation and matter evolution can be exactly calculated, without approximations such as small amplitude of the density contrast. This will allow us to examine the impact of light propagation effects on the CMB temperature fluctuations. The results of such analysis show that small-scale, non-linear inhomogeneities introduce - via light propagation effect...

  3. Obs4MIPS: Satellite Observations for Model Evaluation

    Science.gov (United States)

    Ferraro, R.; Waliser, D. E.; Gleckler, P. J.

    2015-12-01

    This poster will review the current status of the obs4MIPs project, whose purpose is to provide a limited collection of well-established and documented datasets for comparison with Earth system models (https://www.earthsystemcog.org/projects/obs4mips/). These datasets have been reformatted to correspond with the CMIP5 model output requirements, and include technical documentation specifically targeted for their use in model output evaluation. There are currently over 50 datasets containing observations that directly correspond to CMIP5 model output variables. We will review recent additions to the obs4MIPs collection, and provide updated download statistics. We will also provide an update on changes to submission and documentation guidelines, the work of the WCRP Data Advisory Council (WDAC) Observations for Model Evaluation Task Team, and engagement with the CMIP6 MIP experiments.

  4. Modeling of diffuse molecular gas applied to HD 102065 observations

    CERN Document Server

    Nehme, Cyrine; Boulanger, Francois; Forets, Guillaume Pineau des; Gry, Cecile

    2008-01-01

    Aims. We model a diffuse molecular cloud present along the line of sight to the star HD 102065. We compare our modeling with observations to test our understanding of physical conditions and chemistry in diffuse molecular clouds. Methods. We analyze an extensive set of spectroscopic observations which characterize the diffuse molecular cloud observed toward HD 102065. Absorption observations provide the extinction curve, H2, C I, CO, CH, and CH+ column densities and excitation. These data are complemented by observations of CII, CO and dust emission. Physical conditions are determined using the Meudon PDR model of UV illuminated gas. Results. We find that all observational results, except column densities of CH, CH+ and H2 in its excited (J > 2) levels, are consistent with a cloud model implying a Galactic radiation field (G~0.4 in Draine's unit), a density of 80 cm-3 and a temperature (60-80 K) set by the equilibrium between heating and cooling processes. To account for excited (J >2) H2 levels column densit...

  5. Observations that polar climate modelers use and want

    Science.gov (United States)

    Kay, J. E.; de Boer, G.; Hunke, E. C.; Bailey, D. A.; Schneider, D. P.

    2012-12-01

    Observations are essential for motivating and establishing improvement in the representation of polar processes within climate models. We believe that explicitly documenting the current methods used to develop and evaluate climate models with observations will help inform and improve collaborations between the observational and climate modeling communities. As such, we will present the current strategy of the Polar Climate Working Group (PCWG) to evaluate polar processes within Community Earth System Model (CESM) using observations. Our presentation will focus primarily on PCWG evaluation of atmospheric, sea ice, and surface oceanic processes. In the future, we hope to expand to include land surface, deep ocean, and biogeochemical observations. We hope our presentation, and a related working document developed by the PCWG (https://docs.google.com/document/d/1zt0xParsFeMYhlihfxVJhS3D5nEcKb8A41JH0G1Ic-E/edit) inspires new and useful interactions that lead to improved climate model representation of polar processes relevant to polar climate.

  6. NASA's Earth Observations Commercialization Applications Program: A model for government promotion of commercial space opportunities

    Science.gov (United States)

    Macauley, Molly K.

    1995-01-01

    The role of government in promoting space commerce is a topic of discussion in every spacefaring nation. This article describes a new approach to government intervention which, based on its five-year track record, appears to have met with success. The approach, developed in NASA's Earth Observations Commercialization Application Program (EOCAP), offer several lessons for effective government sponsorship of commercial space development in general and of commercial remote sensing in particular.

  7. MHD models compared with Artemis observations at -60 Re

    Science.gov (United States)

    Gencturk Akay, Iklim; Sibeck, David; Angelopoulos, Vassilis; Kaymaz, Zerefsan; Kuznetsova, Maria

    2016-07-01

    The distant magnetotail has been one of the least studied magnetic regions of the Earth's magnetosphere compared to the other near Earth both dayside and nightside magnetospheric regions owing to the limited number of spacecraft observations. Since 2011, ARTEMIS spacecraft give an excellent opportunity to study the magnetotail at lunar distances in terms of data quality and parameter space. This also gives opportunities to improve the magnetotail models at -60 Re and encourages the modelling studies of the distant magnetotail. Using ARTEMIS data in distant magnetotail, we create magnetic field and plasma flow vector maps in different planes and separated with IMF orientation to understand the magnetotail dynamics at this distance. For this study, we use CCMC's Run-on-Request resources of the MHD models; specifically SWMF-BATS-R-US, OpenGGCM, and LFM and perform the similar analysis with the models. Our main purpose in this study is to measure the performance of the MHD models at -60 Re distant magnetotail by comparing the model results with Artemis observations. In the literature, such a comprehensive comparative study is lacking in the distant tail. Preliminary results show that in general all three models underestimate the magnetic field structure while overestimating the flow speed. In the cross-sectional view, LFM seems to produce the better agreement with the observations. A clear dipolar magnetic field structure is seen with dawn-dusk asymmetry in all models owing to slight positive IMF By but the effect was found to be exaggerated. All models show tailward flows at this distance of the magnetotail, most possibly owing to the magnetic reconnection at the near Earth tail distances. A detailed comparison of several tail characteristics from the models will be presented and discussions will be given with respect to the observations from Artemis at this distance.

  8. Influence of rainfall observation network on model calibration and application

    Directory of Open Access Journals (Sweden)

    A. Bárdossy

    2008-01-01

    Full Text Available The objective in this study is to investigate the influence of the spatial resolution of the rainfall input on the model calibration and application. The analysis is carried out by varying the distribution of the raingauge network. A meso-scale catchment located in southwest Germany has been selected for this study. First, the semi-distributed HBV model is calibrated with the precipitation interpolated from the available observed rainfall of the different raingauge networks. An automatic calibration method based on the combinatorial optimization algorithm simulated annealing is applied. The performance of the hydrological model is analyzed as a function of the raingauge density. Secondly, the calibrated model is validated using interpolated precipitation from the same raingauge density used for the calibration as well as interpolated precipitation based on networks of reduced and increased raingauge density. Lastly, the effect of missing rainfall data is investigated by using a multiple linear regression approach for filling in the missing measurements. The model, calibrated with the complete set of observed data, is then run in the validation period using the above described precipitation field. The simulated hydrographs obtained in the above described three sets of experiments are analyzed through the comparisons of the computed Nash-Sutcliffe coefficient and several goodness-of-fit indexes. The results show that the model using different raingauge networks might need re-calibration of the model parameters, specifically model calibrated on relatively sparse precipitation information might perform well on dense precipitation information while model calibrated on dense precipitation information fails on sparse precipitation information. Also, the model calibrated with the complete set of observed precipitation and run with incomplete observed data associated with the data estimated using multiple linear regressions, at the locations treated as

  9. Foundation observation of teaching project--a developmental model of peer observation of teaching.

    Science.gov (United States)

    Pattison, Andrew Timothy; Sherwood, Morgan; Lumsden, Colin James; Gale, Alison; Markides, Maria

    2012-01-01

    Peer observation of teaching is important in the development of educators. The foundation curriculum specifies teaching competencies that must be attained. We created a developmental model of peer observation of teaching to help our foundation doctors achieve these competencies and develop as educators. A process for peer observation was created based on key features of faculty development. The project consisted of a pre-observation meeting, the observation, a post-observation debrief, writing of reflective reports and group feedback sessions. The project was evaluated by completion of questionnaires and focus groups held with both foundation doctors and the students they taught to achieve triangulation. Twenty-one foundation doctors took part. All completed reflective reports on their teaching. Participants described the process as useful in their development as educators, citing specific examples of changes to their teaching practice. Medical students rated the sessions as better or much better quality as their usual teaching. The study highlights the benefits of the project to individual foundation doctors, undergraduate medical students and faculty. It acknowledges potential anxieties involved in having teaching observed. A structured programme of observation of teaching can deliver specific teaching competencies required by foundation doctors and provides additional benefits.

  10. A Generalized Ideal Observer Model for Decoding Sensory Neural Responses

    Directory of Open Access Journals (Sweden)

    Gopathy ePurushothaman

    2013-09-01

    Full Text Available We show that many ideal observer models used to decode neural activity can be generalizedto a conceptually and analytically simple form. This enables us to study the statisticalproperties of this class of ideal observer models in a unified manner. We consider in detailthe problem of estimating the performance of this class of models. We formulate the problemde novo by deriving two equivalent expressions for the performance and introducing the correspondingestimators. We obtain a lower bound on the number of observations (N requiredfor the estimate of the model performance to lie within a specified confidence interval at aspecified confidence level. We show that these estimators are unbiased and consistent, withvariance approaching zero at the rate of 1/N. We find that the maximum likelihood estimatorfor the model performance is not guaranteed to be the minimum variance estimator even forsome simple parametric forms (e.g., exponential of the underlying probability distributions.We discuss the application of these results for designing and interpreting neurophysiologicalexperiments that employ specific instances of this ideal observer model.

  11. Blending Pan-European and local hydrological models for water resource assessment in Mediterranean areas: lessons learnt from a mountainous catchment

    Science.gov (United States)

    José Polo, María; José Pérez-Palazón, María; Saénz de Rodrigáñez, Marta; Pimentel, Rafael; Arheimer, Berit

    2017-04-01

    Global hydrological models provide scientists and technicians with distributed data over medium to large areas from which assessment of water resource planning and use can be easily performed. However, scale conflicts between global models' spatial resolution and the local significant spatial scales in heterogeneous areas usually pose a constraint for the direct use and application of these models' results. The SWICCA (Service for Water Indicators in Climate Change Adaptation) Platform developed under the Copernicus Climate Change Service (C3S) offers a wide range of both climate and hydrological indicators obtained on a global scale with different time and spatial resolutions. Among the different study cases supporting the SWICCA demonstration of local impact assessment, the Sierra Nevada study case (South Spain) is a representative example of mountainous coastal catchments in the Mediterranean region. This work shows the lessons learnt during the study case development to derive local impact indicator tailored to suit the local end-users of water resource in this snow-dominated area. Different approaches were followed to select the most accurate method to downscale the global data and variables to the local level in a highly abrupt topography, in a sequential step approach. 1) SWICCA global climate variable downscaling followed by river flow simulation from a local hydrological model in selected control points in the catchment, together with 2) SWICCA global river flow values downscaling to the control points followed by corrections with local transfer functions were both tested against the available local river flow series of observations during the reference period. This test was performed for the different models and the available spatial resolutions included in the SWICCA platform. From the results, the second option, that is, the use of SWICCA river flow variables, performed the best approximations, once the local transfer functions were applied to the

  12. A hybrid double-observer sightability model for aerial surveys

    Science.gov (United States)

    Griffin, Paul C.; Lubow, Bruce C.; Jenkins, Kurt J.; Vales, David J.; Moeller, Barbara J.; Reid, Mason; Happe, Patricia J.; Mccorquodale, Scott M.; Tirhi, Michelle J.; Schaberi, Jim P.; Beirne, Katherine

    2013-01-01

    Raw counts from aerial surveys make no correction for undetected animals and provide no estimate of precision with which to judge the utility of the counts. Sightability modeling and double-observer (DO) modeling are 2 commonly used approaches to account for detection bias and to estimate precision in aerial surveys. We developed a hybrid DO sightability model (model MH) that uses the strength of each approach to overcome the weakness in the other, for aerial surveys of elk (Cervus elaphus). The hybrid approach uses detection patterns of 2 independent observer pairs in a helicopter and telemetry-based detections of collared elk groups. Candidate MH models reflected hypotheses about effects of recorded covariates and unmodeled heterogeneity on the separate front-seat observer pair and back-seat observer pair detection probabilities. Group size and concealing vegetation cover strongly influenced detection probabilities. The pilot's previous experience participating in aerial surveys influenced detection by the front pair of observers if the elk group was on the pilot's side of the helicopter flight path. In 9 surveys in Mount Rainier National Park, the raw number of elk counted was approximately 80–93% of the abundance estimated by model MH. Uncorrected ratios of bulls per 100 cows generally were low compared to estimates adjusted for detection bias, but ratios of calves per 100 cows were comparable whether based on raw survey counts or adjusted estimates. The hybrid method was an improvement over commonly used alternatives, with improved precision compared to sightability modeling and reduced bias compared to DO modeling.

  13. Observational constraints on the generalized $\\alpha$ attractor model

    CERN Document Server

    Shahalam, M; Myrzakul, Shynaray; Wang, Anzhong

    2016-01-01

    We study the generalized $\\alpha$ attractor model in context of late time cosmic acceleration; the model interpolates between freezing and thawing dark energy models. In the slow roll regime, the originally potential is modified whereas the modification ceases in the asymptotic regime and the effective potential behaves as quadratic. In our setting, field rolls slowly around the present epoch and mimics dark matter in future. We put observational constraints on the model parameters for which we use an integrated data base (SN+Hubble+BAO+CMB) for carrying out the data analysis.

  14. Testing protostellar disk formation models with ALMA observations

    CERN Document Server

    Harsono, Daniel; Bruderer, Simon; Li, Zhi-Yun; Jorgensen, Jes

    2015-01-01

    Abridged: Recent simulations have explored different ways to form accretion disks around low-mass stars. We aim to present observables to differentiate a rotationally supported disk from an infalling rotating envelope toward deeply embedded young stellar objects and infer their masses and sizes. Two 3D magnetohydrodynamics (MHD) formation simulations and 2D semi-analytical model are studied. The dust temperature structure is determined through continuum radiative transfer RADMC3D modelling. A simple temperature dependent CO abundance structure is adopted and synthetic spectrally resolved submm rotational molecular lines up to $J_{\\rm u} = 10$ are simulated. All models predict similar compact components in continuum if observed at the spatial resolutions of 0.5-1$"$ (70-140 AU) typical of the observations to date. A spatial resolution of $\\sim$14 AU and high dynamic range ($> 1000$) are required to differentiate between RSD and pseudo-disk in the continuum. The peak-position velocity diagrams indicate that the...

  15. Modeling the Compton Hump Reverberation Observed in Active Galactic Nuclei

    Science.gov (United States)

    Hoormann, Janie; Beheshtipour, Banafsheh; Krawczynski, Henric

    2016-04-01

    In recent years, observations of the Iron K alpha reverberation in supermassive black holes have provided a new way to probe the inner accretion flow. Furthermore, a time lag between the direct coronal emission and the reprocessed emission forming the Compton Hump in AGN has been observed. In order to model this Compton Hump reverberation we performed general relativistic ray tracing studies of the accretion disk surrounding supermassive black holes, taking into account both the radial and angular dependence of the ionization parameter. We are able to model emission not only from a lamp-post corona but also implementing 3D corona geometries. Using these results we are able to model the observed data to gain additional insight into the geometry of the corona and the structure of the inner accretion disk.

  16. Model-independent inference on compact-binary observations

    CERN Document Server

    Mandel, Ilya; Colonna, Andrea; Stevenson, Simon; Tiňo, Peter; Veitch, John

    2016-01-01

    The recent advanced LIGO detections of gravitational waves from merging binary black holes enhance the prospect of exploring binary evolution via gravitational-wave observations of a population of compact-object binaries. In the face of uncertainty about binary formation models, model-independent inference provides an appealing alternative to comparisons between observed and modelled populations. We describe a procedure for clustering in the multi-dimensional parameter space of observations that are subject to significant measurement errors. We apply this procedure to a mock data set of population-synthesis predictions for the masses of merging compact binaries convolved with realistic measurement uncertainties, and demonstrate that we can accurately distinguish subpopulations of binary neutron stars, binary black holes, and mixed black hole -- neutron star binaries.

  17. Small RNA pathways and diversity in model legumes: lessons from genomics.

    Directory of Open Access Journals (Sweden)

    Pilar eBustos-Sanmamed

    2013-07-01

    Full Text Available Small non coding RNAs (smRNA participate in the regulation of development, cell differentiation, adaptation to environmental constraints and defense responses in plants. They negatively regulate gene expression by degrading specific mRNA targets, repressing their translation or modifying chromatin conformation through homologous interaction with target loci. MicroRNAs (miRNA and short-interfering RNAs (siRNA are generated from long double stranded RNA (dsRNA that are cleaved into 20- to 24-nucleotide dsRNAs by RNase III proteins called DICERs (DCL. One strand of the duplex is then loaded onto effective complexes containing different ARGONAUTE (AGO proteins. In this review, we explored smRNA diversity in model legumes and compiled available data from miRBAse, the miRNA database, and from 22 reports of smRNA deep sequencing or miRNA identification genome-wide in Medicago truncatula, Glycine max and Lotus japonicus. In addition to conserved miRNAs present in other plant species, 229, 179 and 35 novel miRNA families were identified respectively in these 3 legumes, among which several seems legume-specific. New potential functions of several miRNAs in the legume-specific nodulation process are discussed. Furthermore, a new category of siRNA, the phased siRNAs, which seems to mainly regulate disease-resistance genes, was recently discovered in legumes. Despite that the genome sequence of model legumes are not yet fully completed, further analysis was performed by database mining of gene families and protein characteristics of DCLs and AGOs in these genomes. Although most components of the smRNA pathways are conserved, identifiable homologs of key smRNA players from non-legumes could not yet be detected in M. truncatula available genomic and expressed sequence databases. In addition, an important gene diversification was observed in the three legumes. Functional significance of these variant isoforms may reflect peculiarities of smRNA biogenesis in

  18. Solar Spectral Irradiance Variability in Cycle 24: Observations and Models

    CERN Document Server

    Marchenko, S V; Lean, J L

    2016-01-01

    Utilizing the excellent stability of the Ozone Monitoring Instrument (OMI), we characterize both short-term (solar rotation) and long-term (solar cycle) changes of the solar spectral irradiance (SSI) between 265-500 nm during the on-going Cycle 24. We supplement the OMI data with concurrent observations from the GOME-2 and SORCE instruments and find fair-to-excellent, depending on wavelength, agreement among the observations and predictions of the NRLSSI2 and SATIRE-S models.

  19. Developing Noticing of Reasoning through Demonstration Lessons

    Science.gov (United States)

    Bragg, Leicha A.; Vale, Colleen

    2014-01-01

    Observation of fellow educators conducting demonstration lessons is one avenue for teachers to develop sensitivity to noticing students' reasoning. We examined teachers' noticing of children's learning behaviours in one demonstration lesson of the "Mathematical Reasoning Professional Learning Research Program" (MRPLRP). The observations…

  20. Diagnostic Modeling of PAMS VOC Observation on Regional Scale Environment

    Science.gov (United States)

    Chen, S.; Liu, T.; Chen, T.; Ou Yang, C.; Wang, J.; Chang, J. S.

    2008-12-01

    While a number of gas-phase chemical mechanisms, such as CBM-Z, RADM2, SAPRC-07 had been successful in studying gas-phase atmospheric chemical processes they all used some lumped organic species to varying degrees. Photochemical Assessment Monitoring Stations (PAMS) has been in use for over ten years and yet it is not clear how the detailed organic species measured by PAMS compare to the lumped model species under regional-scale transport and chemistry interactions. By developing a detailed mechanism specifically for the PAMS organics and embedding this diagnostic model within a regional-scale transport and chemistry model we can then directly compare PAMS observation with regional-scale model simulations. We modify one regional-scale chemical transport model (Taiwan Air Quality Model, TAQM) by adding a submodel with chemical mechanism for interactions of the 56 species observed by PAMS. This submodel then calculates the time evolution of these 56 PAMS species within the environment established by TAQM. It is assumed that TAQM can simulate the overall regional-scale environment including impact of regional-scale transport and time evolution of oxidants and radicals. Therefore we can scale these influences to the PAMS organic species and study their time evolution with their species-specific source functions, meteorological transport, and chemical interactions. Model simulations of each species are compared with PAMS hourly surface measurements. A case study located in a metropolitan area in central Taiwan showed that with wind speeds lower than 3 m/s, when meteorological simulation is comparable with observation, the diurnal pattern of each species performs well with PAMS data. It is found that for many observations meteorological transport is an influence and that local emissions of specific species must be represented correctly. At this time there are still species that cannot be modeled properly. We suspect this is mostly due to lack of information on local

  1. Optimal designs for the Michaelis Menten model with correlated observations

    OpenAIRE

    Dette, Holger; Kunert, Joachim

    2012-01-01

    In this paper we investigate the problem of designing experiments for weighted least squares analysis in the Michaelis Menten model. We study the structure of exact D-optimal designs in a model with an autoregressive error structure. Explicit results for locally D-optimal are derived for the case where 2 observations can be taken per subject. Additionally standardized maximin D-optimal designs are obtained in this case. The results illustrate the enormous difficulties to find e...

  2. The Martian Plasma Environment: Model Calculations and Observations

    Science.gov (United States)

    Lichtenegger, H. I. M.; Dubinin, E.; Schwingenschuh, K.; Riedler, W.

    Based on a modified version of the model of an induced martian magnetosphere developed by Luhmann (1990), the dynamics and spatial distribution of different planetary ion species is examined. Three main regions are identified: A cloud of ions travelling along cycloidal trajectories, a plasma mantle and a plasma sheet. The latter predominantly consists of oxygen ions of ionospheric origin with minor portions of light particles. Comparison of model results with Phobos-2 observations shows reasonable agreement.

  3. Scale invariant cosmology III: dynamical models and comparisons with observations

    CERN Document Server

    Maeder, Andre

    2016-01-01

    We examine the properties of the scale invariant cosmological models, also making the specific hypothesis of the scale invariance of the empty space at large scales. Numerical integrations of the cosmological equations for different values of the curvature parameter k and of the density parameter Omega_m are performed. We compare the dynamical properties of the models to the observations at different epochs. The main numerical data and graphical representations are given for models computed with different curvatures and density parameters. The models with non-zero density start explosively with first a braking phase followed by a continuously accelerating expansion. The comparison of the models with the recent observations from supernovae SN Ia, BAO and CMB data from Planck 2015 shows that the scale invariant model with k=0 and Omega_m=0.30 very well fits the observations in the usual Omega_m vs. Omega_Lambda plane and consistently accounts for the accelerating expansion or dark energy. The expansion history ...

  4. Observations and Modeling of Solar Flare Atmospheric Dynamics

    Science.gov (United States)

    Li, Y.

    2015-09-01

    Solar flares are one of the most energetic events in solar atmosphere, which last minutes to tens of minutes. The eruption of a solar flare involves energy release, plasma heating, particle acceleration, mass flows, waves, etc. A solar flare releases a large amount of energy, and its emission spans a wide wavelength range. Solar flares are usually accompanied by coronal mass ejections (CMEs); therefore they could significantly affect the space environments between the Earth and the Sun. At present, we do not fully understand the whole flare process. There are still many important questions to be resolved, such as when and where is the energy released? How long does the energy release last? What are the main ways of energy release? And how does the solar atmosphere respond to the energy release? To address these questions, we study in detail the flare heating and dynamic evolution. We first give a brief review of previous flare studies (Chapter 1), and introduce the observing instruments (Chapter 2) and the modeling method (Chapter 3) related to this thesis work. Then we use spectral data to investigate the chromospheric evaporation (Chapter 4). Based on the results, we further explore the flare heating problem. With observationally inferred heating functions, we model two flare loops, and compare the results with observations (Chapter 5). A consistency is achieved between modeling and observations. In addition, we model two different sets of flare loop systems with quite different heating profiles and dynamic evolutions (Chapter 6). The details are described as below. Firstly, we investigate the chromospheric evaporation in the flare on 2007 January 16 using line profiles observed by the Extreme-ultraviolet (EUV) Imaging Spectrometer (EIS) on board Hinode. Three points with different magnetic polarities at flare ribbons are analyzed in detail. We find that the three points show different patterns of upflows and downflows in the impulsive phase of the flare. The

  5. Learning from History: A Lesson on the Model of the Earth

    Science.gov (United States)

    Liu, Shu-Chiu

    2006-01-01

    It is suggested that historical material concerning the model of the earth be utilised in the science classroom to construct narrative explanations. The article includes the various ancient models of the earth, the discovery of the spherical earth model, and the arguments and experiments coupled with it. Its instructional gain may lie in the…

  6. Linking Geomechanical Models with Observations of Microseismicity during CCS Operations

    Science.gov (United States)

    Verdon, J.; Kendall, J.; White, D.

    2012-12-01

    During CO2 injection for the purposes of carbon capture and storage (CCS), injection-induced fracturing of the overburden represents a key risk to storage integrity. Fractures in a caprock provide a pathway along which buoyant CO2 can rise and escape the storage zone. Therefore the ability to link field-scale geomechanical models with field geophysical observations is of paramount importance to guarantee secure CO2 storage. Accurate location of microseismic events identifies where brittle failure has occurred on fracture planes. This is a manifestation of the deformation induced by CO2 injection. As the pore pressure is increased during injection, effective stress is decreased, leading to inflation of the reservoir and deformation of surrounding rocks, which creates microseismicity. The deformation induced by injection can be simulated using finite-element mechanical models. Such a model can be used to predict when and where microseismicity is expected to occur. However, typical elements in a field scale mechanical models have decameter scales, while the rupture size for microseismic events are typically of the order of 1 square meter. This means that mapping modeled stress changes to predictions of microseismic activity can be challenging. Where larger scale faults have been identified, they can be included explicitly in the geomechanical model. Where movement is simulated along these discrete features, it can be assumed that microseismicity will occur. However, microseismic events typically occur on fracture networks that are too small to be simulated explicitly in a field-scale model. Therefore, the likelihood of microseismicity occurring must be estimated within a finite element that does not contain explicitly modeled discontinuities. This can be done in a number of ways, including the utilization of measures such as closeness on the stress state to predetermined failure criteria, either for planes with a defined orientation (the Mohr-Coulomb criteria) for

  7. Graduate students teaching elementary earth science through interactive classroom lessons

    Science.gov (United States)

    Caswell, T. E.; Goudge, T. A.; Jawin, E. R.; Robinson, F.

    2014-12-01

    Since 2005, graduate students in the Brown University Department of Earth, Environmental, and Planetary Studies have volunteered to teach science to second-grade students at Vartan Gregorian Elementary School in Providence, RI. Initially developed to bring science into classrooms where it was not explicitly included in the curriculum, the graduate student-run program today incorporates the Providence Public Schools Grade 2 science curriculum into weekly, interactive sessions that engage the students in hypothesis-driven science. We will describe the program structure, its integration into the Providence Public Schools curriculum, and 3 example lessons relevant to geology. Lessons are structured to develop the students' ability to share and incorporate others' ideas through written and oral communication. The volunteers explain the basics of the topic and engage the students with introductory questions. The students use this knowledge to develop a hypothesis about the upcoming experiment, recording it in their "Science Notebooks." The students record their observations during the demonstration and discuss the results as a group. The process culminates in the students using their own words to summarize what they learned. Activities of particular interest to educators in geoscience are called "Volcanoes!", "The "Liquid Race," and "Phases of the Moon." The "Volcanoes!" lesson explores explosive vs. effusive volcanism using two simulated volcanoes: one explosive, using Mentos and Diet Coke, and one effusive, using vinegar and baking soda (in model volcanoes that the students construct in teams). In "Liquid Race," which explores viscosity and can be integrated into the "Volcanoes!" lesson, the students connect viscosity to flow speed by racing liquids down a ramp. "Phases of the Moon" teaches the students why the Moon has phases, using ball and stick models, and the terminology of the lunar phases using cream-filled cookies (e.g., Oreos). These lessons, among many others

  8. Calibration of a numerical ionospheric model with EISCAT observations

    Directory of Open Access Journals (Sweden)

    P.-L. Blelly

    Full Text Available A set of EISCAT UHF and VHF observations is used for calibrating a coupled fluid-kinetic model of the ionosphere. The data gathered in the period 1200- 2400 UT on 24 March 1995 had various intervals of interest for such a calibration. The magnetospheric activity was very low during the afternoon, allowing for a proper examination of a case of quiet ionospheric conditions. The radars entered the auroral oval just after 1900 UT: a series of dynamic events probably associated with rapidly moving auroral arcs was observed until after 2200 UT. No attempts were made to model the dynamical behaviour during the 1900–2200 UT period. In contrast, the period 2200–2400 UT was characterised by quite steady precipitation: this latter period was then chosen for calibrating the model during precipitation events. The adjustment of the model on the four primary parameters observed by the radars (namely the electron concentration and temperature and the ion temperature and velocity needed external inputs (solar fluxes and magnetic activity index and the adjustments of a neutral atmospheric model in order to reach a good agreement. It is shown that for the quiet ionosphere, only slight adjustments of the neutral atmosphere models are needed. In contrast, adjusting the observations during the precipitation event requires strong departures from the model, both for the atomic oxygen and hydrogen. However, it is argued that this could well be the result of inadequately representing the vibrational states of N2 during precipitation events, and that these factors have to be considered only as ad hoc corrections.

  9. Observation-based correction of dynamical models using thermostats

    Science.gov (United States)

    Frank, Jason; Leimkuhler, Benedict

    2017-01-01

    Models used in simulation may give accurate short-term trajectories but distort long-term (statistical) properties. In this work, we augment a given approximate model with a control law (a ‘thermostat’) that gently perturbs the dynamical system to target a thermodynamic state consistent with a set of prescribed (possibly evolving) observations. As proof of concept, we provide an example involving a point vortex fluid model on the sphere, for which we show convergence of equilibrium quantities (in the stationary case) and the ability of the thermostat to dynamically track a transient state. PMID:28265197

  10. Unsteady aerodynamic modeling based on POD-observer method

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A new hybrid approach to constructing reduced-order models(ROM)of unsteady aerodynamics applicable to aeroelastic analysis is presented by using proper orthogonal decomposition(POD)in combination with observer techniques.Fluid modes are generated through POD by sampling observations of solutions derived from the full-order model.The response in the POD training is projected onto the fluid modes to determine the time history of the modal amplitudes.The resulting data are used to extract the Markov parameters of the low-dimensional model for modal amplitudes using a related deadbeat observer.The state-space realization is synthesized from the system’s Markov parameters that are processed with the eigensystem realization algorithm.The POD-observer method is applied to a two-dimensional airfoil system in subsonic flow field.The results predicted by the ROM are in general agreement with those from the full-order system.The ROM obtained by the hybrid approach captures the essence of a fluid system and produces vast reduction in both degrees of freedom and computational time relative to the full-order model.

  11. Sixth International Workshop on the Mars Atmosphere: Modelling and Observations

    Science.gov (United States)

    Forget, F.; Millour, M.

    2017-01-01

    The scope of this workshop is to bring together experts in observations and modelling of the present and past Mars climate systems and discuss the nature of the atmospheric circulation and the photochemistry (up to the thermosphere), the dust cycle, the water cycle (vapor, clouds and frost) and the carbon dioxide cycle (polar caps).

  12. Observations and models for needle-tissue interactions

    NARCIS (Netherlands)

    Misra, Sarthak; Reed, Kyle B.; Schafer, Benjamin W.; Ramesh, K.T.; Okamura, Allison M.

    2009-01-01

    The asymmetry of a bevel-tip needle results in the needle naturally bending when it is inserted into soft tissue. In this study we present a mechanics-based model that calculates the deflection of the needle embedded in an elastic medium. Microscopic observations for several needle- gel interactions

  13. S-AMP for non-linear observation models

    DEFF Research Database (Denmark)

    Cakmak, Burak; Winther, Ole; Fleury, Bernard H.

    2015-01-01

    Recently we presented the S-AMP approach, an extension of approximate message passing (AMP), to be able to handle general invariant matrix ensembles. In this contribution we extend S-AMP to non-linear observation models. We obtain generalized AMP (GAMP) as the special case when the measurement...

  14. Lesson Learning at JPL

    Science.gov (United States)

    Oberhettinger, David

    2011-01-01

    A lessons learned system is a hallmark of a mature engineering organization A formal lessons learned process can help assure that valuable lessons get written and published, that they are well-written, and that the essential information is "infused" into institutional practice. Requires high-level institutional commitment, and everyone's participation in gathering, disseminating, and using the lessons

  15. Lesson Learning at JPL

    Science.gov (United States)

    Oberhettinger, David

    2011-01-01

    A lessons learned system is a hallmark of a mature engineering organization A formal lessons learned process can help assure that valuable lessons get written and published, that they are well-written, and that the essential information is "infused" into institutional practice. Requires high-level institutional commitment, and everyone's participation in gathering, disseminating, and using the lessons

  16. Some observational tests of a minimal galaxy formation model

    CERN Document Server

    Cohn, J D

    2016-01-01

    Dark matter simulations can serve as a basis for creating galaxy histories via the galaxy-dark matter connection. Here, one such model by Becker (2015) is implemented with several variations on three different dark matter simulations. Stellar mass and star formation rates are assigned to all simulation subhalos at all times, using subhalo mass gain to determine stellar mass gain. The observational properties of the resulting galaxy distributions are compared to each other and observations for a range of redshifts from 0-2. Although many of the galaxy distributions seem reasonable, there are noticeable differences as simulations, subhalo mass gain definitions, or subhalo mass definitions are altered, suggesting that the model should change as these properties are varied. Agreement with observations may improve by including redshift dependence in the added-by-hand random contribution to star formation rate. There appears to be an excess of faint quiescent galaxies as well (perhaps due in part to differing defin...

  17. ENLIL Global Heliospheric Modeling as a Context For Multipoint Observations

    Science.gov (United States)

    Mays, M. Leila; Odstrcil, Dusan; Luhmann, Janet; Bain, Hazel; Li, Yan; Schwadron, Nathan; Gorby, Matt; Thompson, Barbara; Jian, Lan; Möstl, Christian; Rouillard, Alexis; Davies, Jackie; Temmer, Manuela; Rastaetter, Lutz; Taktakishvili, Aleksandre; MacNeice, Peter; Kuznetsova, Maria

    2016-04-01

    We present heliospheric simulation case studies using recent enhancements to WSA--ENLIL+Cone (version 2.8) at the Community Coordinated Modeling Center (CCMC). The global 3D MHD ENLIL model provides a time-dependent description of the background solar wind plasma and magnetic field using a sequence of WSA coronal model maps as input at the inner boundary of 21.5 Rs. A homogeneous, over-pressured hydrodynamic plasma cloud is launched through the inner boundary of the heliospheric computational domain and into the background solar wind. Multipoint observations help constrain simulations and this modeling system provides global context and arrival times of the solar wind streams and CMEs at Earth, planets, and spacecraft. Additionally, one can extract the magnetic topologies of observer-connected magnetic field lines and all plasma and shock properties along those field lines. ENLIL "likelihood/all-clear" forecasting maps provide expected intensity, timing/duration of events at locations throughout the heliosphere with "possible SEP affected areas" color-coded based on shock strength. ENLIL simulations are also useful to drive SEP models such as the Solar Energetic Particle Model (SEPMOD) (Luhmann et al. 2007, 2010) and Energetic Particle Radiation Environment Module (EPREM) (Schwadron et al., 2010). SEPMOD injects protons onto a sequence observer field lines at intensities dependent on the connected shock source strength which are then integrated at the observer to approximate the proton flux. EPREM couples with MHD models such as ENLIL and computes energetic particle distributions based on the focused transport equation along a Lagrangian grid of nodes that propagate out with the solar wind. Studies have shown that accurate descriptions of the heliosphere, and hence modeled CME arrival times and SEPs, are achieved by ENLIL only when the background solar wind is well-reproduced and CME parameters are accurate. It is essential to include all of the relevant CMEs and

  18. Testing the Empirical Shock Arrival Model using Quadrature Observations

    CERN Document Server

    Gopalswamy, N; Xie, H; Yashiro, S

    2013-01-01

    The empirical shock arrival (ESA) model was developed based on quadrature data from Helios (in-situ) and P-78 (remote-sensing) to predict the Sun-Earth travel time of coronal mass ejections (CMEs) [Gopalswamy et al. 2005a]. The ESA model requires earthward CME speed as input, which is not directly measurable from coronagraphs along the Sun-Earth line. The Solar Terrestrial Relations Observatory (STEREO) and the Solar and Heliospheric Observatory (SOHO) were in quadrature during 2010 - 2012, so the speeds of Earth-directed CMEs were observed with minimal projection effects. We identified a set of 20 full halo CMEs in the field of view of SOHO that were also observed in quadrature by STEREO. We used the earthward speed from STEREO measurements as input to the ESA model and compared the resulting travel times with the observed ones from L1 monitors. We find that the model predicts the CME travel time within about 7.3 hours, which is similar to the predictions by the ENLIL model. We also find that CME-CME and CME...

  19. The Validation of Computer-based Models in Engineering: Some Lessons from Computing Science

    Directory of Open Access Journals (Sweden)

    D. J. Murray-Smith

    2001-01-01

    Full Text Available Questions of the quality of computer-based models and the formal processes of model testing, involving internal verification and external validation, are usually given only passing attention in engineering reports and in technical publications. However, such models frequently provide a basis for analysis methods, design calculations or real-time decision-making in complex engineering systems. This paper reviews techniques used for external validation of computer-based models and contrasts the somewhat casual approach which is usually adopted in this field with the more formal approaches to software testing and documentation recommended for large software projects. Both activities require intimate knowledge of the intended application, a systematic approach and considerable expertise and ingenuity in the design of tests. It is concluded that engineering degree courses dealing with modelling techniques and computer simulation should put more emphasis on model limitations, testing and validation.

  20. Linear system identification via backward-time observer models

    Science.gov (United States)

    Juang, Jer-Nan; Phan, Minh

    1993-01-01

    This paper presents an algorithm to identify a state-space model of a linear system using a backward-time approach. The procedure consists of three basic steps. First, the Markov parameters of a backward-time observer are computed from experimental input-output data. Second, the backward-time observer Markov parameters are decomposed to obtain the backward-time system Markov parameters (backward-time pulse response samples) from which a backward-time state-space model is realized using the Eigensystem Realization Algorithm. Third, the obtained backward-time state space model is converted to the usual forward-time representation. Stochastic properties of this approach will be discussed. Experimental results are given to illustrate when and to what extent this concept works.

  1. How Does Lesson Study Improve Mathematics Instruction?

    Science.gov (United States)

    Lewis, Catherine

    2016-01-01

    This article presents a theoretical model of lesson study's impact on instruction, through intervening impact on teachers' knowledge, beliefs and dispositions, teachers' learning community, and curriculum. It also describes four different types of lesson study in Japan, pointing out their synergies in producing a system where local teachers…

  2. Comparing models of star formation simulating observed interacting galaxies

    Science.gov (United States)

    Quiroga, L. F.; Muñoz-Cuartas, J. C.; Rodrigues, I.

    2017-07-01

    In this work, we make a comparison between different models of star formation to reproduce observed interacting galaxies. We use observational data to model the evolution of a pair of galaxies undergoing a minor merger. Minor mergers represent situations weakly deviated from the equilibrium configuration but significant changes in star fomation (SF) efficiency can take place, then, minor mergers provide an unique scene to study SF in galaxies in a realistic but yet simple way. Reproducing observed systems also give us the opportunity to compare the results of the simulations with observations, which at the end can be used as probes to characterize the models of SF implemented in the comparison. In this work we compare two different star formation recipes implemented in Gadget3 and GIZMO codes. Both codes share the same numerical background, and differences arise mainly in the star formation recipe they use. We use observations from Pico dos Días and GEMINI telescopes and show how we use observational data of the interacting pair in AM2229-735 to characterize the interacting pair. Later we use this information to simulate the evolution of the system to finally reproduce the observations: Mass distribution, morphology and main features of the merger-induced star formation burst. We show that both methods manage to reproduce roughly the star formation activity. We show, through a careful study, that resolution plays a major role in the reproducibility of the system. In that sense, star formation recipe implemented in GIZMO code has shown a more robust performance. Acknowledgements: This work is supported by Colciencias, Doctorado Nacional - 617 program.

  3. Applying direct observation to model workflow and assess adoption.

    Science.gov (United States)

    Unertl, Kim M; Weinger, Matthew B; Johnson, Kevin B

    2006-01-01

    Lack of understanding about workflow can impair health IT system adoption. Observational techniques can provide valuable information about clinical workflow. A pilot study using direct observation was conducted in an outpatient chronic disease clinic. The goals of the study were to assess workflow and information flow and to develop a general model of workflow and information behavior. Over 55 hours of direct observation showed that the pilot site utilized many of the features of the informatics systems available to them, but also employed multiple non-electronic artifacts and workarounds. Gaps existed between clinic workflow and informatics tool workflow, as well as between institutional expectations of informatics tool use and actual use. Concurrent use of both paper-based and electronic systems resulted in duplication of effort and inefficiencies. A relatively short period of direct observation revealed important information about workflow and informatics tool adoption.

  4. Inferring effective field observables from a discrete model

    Science.gov (United States)

    Bény, Cédric

    2017-01-01

    A spin system on a lattice can usually be modeled at large scales by an effective quantum field theory. A key mathematical result relating the two descriptions is the quantum central limit theorem, which shows that certain spin observables satisfy an algebra of bosonic fields under certain conditions. Here, we show that these particular observables and conditions are the relevant ones for an observer with certain limited abilities to resolve spatial locations as well as spin values. This is shown by computing the asymptotic behaviour of a quantum Fisher information metric as function of the resolution parameters. The relevant observables characterise the state perturbations whose distinguishability does not decay too fast as a function of spatial or spin resolution.

  5. Tidal Movement of Nioghalvfjerdsfjorden Glacier, Northeast Greenland: Observations and Modelling

    DEFF Research Database (Denmark)

    Reeh, Niels; Mayer, C.; Olesen, O. B.

    2000-01-01

    , 1997 and 1998. As part of this work, tidal-movement observations were carried out by simultaneous differential global positioning system (GPS) measurements at several locations distributed on the glacier surface. The GPS observations were performed continuously over several tidal cycles. At the same....... The observations show that the main part of the glacier tongue responds as a freely floating plate to the phase and amplitude of the local tide in the sea. However, kilometre-wide flexure zones exist along the marginal and upstream grounding lines. Attempts to model the observed tidal deflection and tilt patterns...... in the flexure zone by elastic-beam theory are unsuccessful, in contrast to previous findings by other investigators. The strongest disagreement between our measurements and results derived from elastic-beam theory is a significant variation of the phase of the tidal records with distance from the grounding line...

  6. Modeling Information for Three-Dimensional Space: Lessons Learned from Museum Exhibit Design.

    Science.gov (United States)

    Carliner, Saul

    2001-01-01

    Reports results of an observational study of museum exhibit design. Suggests eight communication practices from successful museum exhibit design that could be transferred to information design for the Web. (SR)

  7. Sustainable solar home systems model: Applying lessons from Bangladesh to Myanmar's rural poor

    DEFF Research Database (Denmark)

    Newcombe, Alex; Ackom, Emmanuel

    2017-01-01

    •A PPP-based microfinance model offers great potential for SHSs in rural Myanmar. •The model requires a polycentric structure, local presence and after sale service. •Smart pro-poor subsidies are advised to create a large competitive SHS market. •Assumptions made in the NEP should be revised such...

  8. Reactive surface area in geochemical models - Lessons learned from a natural analogue

    NARCIS (Netherlands)

    Koenen, M.; Wasch, L.J.

    2013-01-01

    Many uncertainties exist in geochemical modeling. Mineral reactive surface area is one of the uncertain parameters. QEMSCAN analyses are performed on sandstone samples from a Dutch CO2 natural analogue to determine reactive surface areas. Geochemical modeling is performed using QEMSCAN surface areas

  9. Pattern-oriented modeling of agent-based complex systems: Lessons from ecology

    Science.gov (United States)

    Grimm, Volker; Revilla, Eloy; Berger, Uta; Jeltsch, Florian; Mooij, Wolf M.; Railsback, Steven F.; Thulke, Hans-Hermann; Weiner, Jacob; Wiegand, Thorsten; DeAngelis, Donald L.

    2005-01-01

    Agent-based complex systems are dynamic networks of many interacting agents; examples include ecosystems, financial markets, and cities. The search for general principles underlying the internal organization of such systems often uses bottom-up simulation models such as cellular automata and agent-based models. No general framework for designing, testing, and analyzing bottom-up models has yet been established, but recent advances in ecological modeling have come together in a general strategy we call pattern-oriented modeling. This strategy provides a unifying framework for decoding the internal organization of agent-based complex systems and may lead toward unifying algorithmic theories of the relation between adaptive behavior and system complexity.

  10. Pattern-oriented modeling of agent-based complex systems: lessons from ecology.

    Science.gov (United States)

    Grimm, Volker; Revilla, Eloy; Berger, Uta; Jeltsch, Florian; Mooij, Wolf M; Railsback, Steven F; Thulke, Hans-Hermann; Weiner, Jacob; Wiegand, Thorsten; DeAngelis, Donald L

    2005-11-11

    Agent-based complex systems are dynamic networks of many interacting agents; examples include ecosystems, financial markets, and cities. The search for general principles underlying the internal organization of such systems often uses bottom-up simulation models such as cellular automata and agent-based models. No general framework for designing, testing, and analyzing bottom-up models has yet been established, but recent advances in ecological modeling have come together in a general strategy we call pattern-oriented modeling. This strategy provides a unifying framework for decoding the internal organization of agent-based complex systems and may lead toward unifying algorithmic theories of the relation between adaptive behavior and system complexity.

  11. Tectonic stressing in California modeled from GPS observations

    Science.gov (United States)

    Parsons, T.

    2006-01-01

    What happens in the crust as a result of geodetically observed secular motions? In this paper we find out by distorting a finite element model of California using GPS-derived displacements. A complex model was constructed using spatially varying crustal thickness, geothermal gradient, topography, and creeping faults. GPS velocity observations were interpolated and extrapolated across the model and boundary condition areas, and the model was loaded according to 5-year displacements. Results map highest differential stressing rates in a 200-km-wide band along the Pacific-North American plate boundary, coinciding with regions of greatest seismic energy release. Away from the plate boundary, GPS-derived crustal strain reduces modeled differential stress in some places, suggesting that some crustal motions are related to topographic collapse. Calculated stressing rates can be resolved onto fault planes: useful for addressing fault interactions and necessary for calculating earthquake advances or delays. As an example, I examine seismic quiescence on the Garlock fault despite a calculated minimum 0.1-0.4 MPa static stress increase from the 1857 M???7.8 Fort Tejon earthquake. Results from finite element modeling show very low to negative secular Coulomb stress growth on the Garlock fault, suggesting that the stress state may have been too low for large earthquake triggering. Thus the Garlock fault may only be stressed by San Andreas fault slip, a loading pattern that could explain its erratic rupture history.

  12. The bootstrapped model--Lessons for the acceptance of intellectual technology.

    Science.gov (United States)

    Lovie, A D

    1987-09-01

    This paper is intended as a non-technical introduction to a growing aspect of what has been termed 'intellectual technology'. The particular area chosen is the use of simple linear additive models for judgement and decision making purposes. Such models are said to either outperform, or perform at least as well as, the human judges on which they are based, hence they are said to 'bootstrap' such human inputs. Although the paper will provide a fairly comprehensive list of recent applications of such models, from postgraduate selection to judgements of marital happiness, the work will concentrate on the topic of Credit Scoring as an exemplar - that is, the assignment of credit by means of a simple additive rule. The paper will also present a simple system, due to Dawes, of classifying such models according to the form and source of their weights. The paper further discusses the reasons for bootstrapping and that other major phenomenon of such models - that is, the one can rarely distinguish between the prescriptions of such models, however the weights have been arrived at. It is argued that this 'principle of the flat maximum' allows us to develop a technology of judgement. The paper continues with a brief historical survey of the reactions of human experts to such models and their superiority, and suggestions for a better mix of expert and model on human engineering lines. Finally, after a brief comparison between expert systems and linear additive models, the paper concludes with a brief survey of possible future developments. A short Appendix describes two applications of such models.

  13. Siberian Arctic black carbon sources constrained by model and observation

    Science.gov (United States)

    Winiger, Patrik; Andersson, August; Eckhardt, Sabine; Stohl, Andreas; Semiletov, Igor P.; Dudarev, Oleg V.; Charkin, Alexander; Shakhova, Natalia; Klimont, Zbigniew; Heyes, Chris; Gustafsson, Örjan

    2017-02-01

    Black carbon (BC) in haze and deposited on snow and ice can have strong effects on the radiative balance of the Arctic. There is a geographic bias in Arctic BC studies toward the Atlantic sector, with lack of observational constraints for the extensive Russian Siberian Arctic, spanning nearly half of the circum-Arctic. Here, 2 y of observations at Tiksi (East Siberian Arctic) establish a strong seasonality in both BC concentrations (8 ngṡm-3 to 302 ngṡm-3) and dual-isotope-constrained sources (19 to 73% contribution from biomass burning). Comparisons between observations and a dispersion model, coupled to an anthropogenic emissions inventory and a fire emissions inventory, give mixed results. In the European Arctic, this model has proven to simulate BC concentrations and source contributions well. However, the model is less successful in reproducing BC concentrations and sources for the Russian Arctic. Using a Bayesian approach, we show that, in contrast to earlier studies, contributions from gas flaring (6%), power plants (9%), and open fires (12%) are relatively small, with the major sources instead being domestic (35%) and transport (38%). The observation-based evaluation of reported emissions identifies errors in spatial allocation of BC sources in the inventory and highlights the importance of improving emission distribution and source attribution, to develop reliable mitigation strategies for efficient reduction of BC impact on the Russian Arctic, one of the fastest-warming regions on Earth.

  14. An observer model for quantifying panning artifacts in digital pathology

    Science.gov (United States)

    Avanaki, Ali R. N.; Espig, Kathryn S.; Xthona, Albert; Lanciault, Christian; Kimpe, Tom R. L.

    2017-03-01

    Typically, pathologists pan from one region of a slide to another, choosing areas of interest for closer inspection. Due to finite frame rate and imperfect zero-order hold reconstruction (i.e., the non-zero time to reach the target brightness after a change in pixel drive), panning in whole slide images (WSI) cause visual artifacts. It is important to study the impact of such artifacts since research suggests that 49% of navigation is conducted in low-power/overview with digital pathology (Molin et al., Histopathology 2015). In this paper, we explain what types of medical information may be harmed by panning artifacts, propose a method to simulate panning artifacts, and design an observer model to predict the impact of panning artifacts on typical human observers' performance in basic diagnostically relevant visual tasks. The proposed observer model is based on derivation of perceived object border maps from luminance and chrominance information and may be tuned to account for visual acuity of the human observer to be modeled. Our results suggest that increasing the contrast (e.g., using a wide gamut display) with a slow response panel may not mitigate the panning artifacts which mostly affect visual tasks involving spatial discrimination of objects (e.g., normal vs abnormal structure, cell type and spatial relationships between them, and low-power nuclear morphology), and that the panning artifacts worsen with increasing panning speed. The proposed methods may be used as building blocks in an automatic WSI quality assessment framework.

  15. Allosteric Learning Model in English Lesson: Teachers' Views, the Instructions of Curriculum and Course Book, a Sample of Daily Lesson Plan

    Science.gov (United States)

    Berkant, Hasan Güner; Baysal, Seda

    2017-01-01

    The changes which occur during the learning process have been explained by many teaching-learning models and theories. One of these models is allosteric learning model (ALM) which was developed by André Giordan in 1989. This model was derived from a biological metaphor related to proteins. The interaction between individual and environment in a…

  16. Observing the observer (I): meta-bayesian models of learning and decision-making.

    Science.gov (United States)

    Daunizeau, Jean; den Ouden, Hanneke E M; Pessiglione, Matthias; Kiebel, Stefan J; Stephan, Klaas E; Friston, Karl J

    2010-12-14

    In this paper, we present a generic approach that can be used to infer how subjects make optimal decisions under uncertainty. This approach induces a distinction between a subject's perceptual model, which underlies the representation of a hidden "state of affairs" and a response model, which predicts the ensuing behavioural (or neurophysiological) responses to those inputs. We start with the premise that subjects continuously update a probabilistic representation of the causes of their sensory inputs to optimise their behaviour. In addition, subjects have preferences or goals that guide decisions about actions given the above uncertain representation of these hidden causes or state of affairs. From a Bayesian decision theoretic perspective, uncertain representations are so-called "posterior" beliefs, which are influenced by subjective "prior" beliefs. Preferences and goals are encoded through a "loss" (or "utility") function, which measures the cost incurred by making any admissible decision for any given (hidden) state of affair. By assuming that subjects make optimal decisions on the basis of updated (posterior) beliefs and utility (loss) functions, one can evaluate the likelihood of observed behaviour. Critically, this enables one to "observe the observer", i.e. identify (context- or subject-dependent) prior beliefs and utility-functions using psychophysical or neurophysiological measures. In this paper, we describe the main theoretical components of this meta-Bayesian approach (i.e. a Bayesian treatment of Bayesian decision theoretic predictions). In a companion paper ('Observing the observer (II): deciding when to decide'), we describe a concrete implementation of it and demonstrate its utility by applying it to simulated and real reaction time data from an associative learning task.

  17. Observing the observer (I: meta-bayesian models of learning and decision-making.

    Directory of Open Access Journals (Sweden)

    Jean Daunizeau

    Full Text Available In this paper, we present a generic approach that can be used to infer how subjects make optimal decisions under uncertainty. This approach induces a distinction between a subject's perceptual model, which underlies the representation of a hidden "state of affairs" and a response model, which predicts the ensuing behavioural (or neurophysiological responses to those inputs. We start with the premise that subjects continuously update a probabilistic representation of the causes of their sensory inputs to optimise their behaviour. In addition, subjects have preferences or goals that guide decisions about actions given the above uncertain representation of these hidden causes or state of affairs. From a Bayesian decision theoretic perspective, uncertain representations are so-called "posterior" beliefs, which are influenced by subjective "prior" beliefs. Preferences and goals are encoded through a "loss" (or "utility" function, which measures the cost incurred by making any admissible decision for any given (hidden state of affair. By assuming that subjects make optimal decisions on the basis of updated (posterior beliefs and utility (loss functions, one can evaluate the likelihood of observed behaviour. Critically, this enables one to "observe the observer", i.e. identify (context- or subject-dependent prior beliefs and utility-functions using psychophysical or neurophysiological measures. In this paper, we describe the main theoretical components of this meta-Bayesian approach (i.e. a Bayesian treatment of Bayesian decision theoretic predictions. In a companion paper ('Observing the observer (II: deciding when to decide', we describe a concrete implementation of it and demonstrate its utility by applying it to simulated and real reaction time data from an associative learning task.

  18. Mechanisms of intestinal inflammation and development of associated cancers: Lessons learned from mouse models

    Science.gov (United States)

    Westbrook, Aya M.; Szakmary, Akos; Schiestl, Robert H.

    2010-01-01

    Chronic inflammation is strongly associated with approximately 1/5th of all human cancers. Arising from combinations of factors such as environmental exposures, diet, inherited gene polymorphisms, infections, or from dysfunctions of the immune response, chronic inflammation begins as an attempt of the body to remove injurious stimuli; however, over time, this results in continuous tissue destruction and promotion and maintenance of carcinogenesis. Here we focus on intestinal inflammation and its associated cancers, a group of diseases on the rise and affecting millions of people worldwide. Intestinal inflammation can be widely grouped into inflammatory bowel diseases (ulcerative colitis and Crohn's disease) and celiac disease. Long-standing intestinal inflammation is associated with colorectal cancer and small-bowel adenocarcinoma, as well as extraintestinal manifestations, including lymphomas and autoimmune diseases. This article highlights potential mechanisms of pathogenesis in inflammatory bowel diseases and celiac disease, as well as those involved in the progression to associated cancers, most of which have been identified from studies utilizing mouse models of intestinal inflammation. Mouse models of intestinal inflammation can be widely grouped into chemically induced models; genetic models, which make up the bulk of the studied models; adoptive transfer models; and spontaneous models. Studies in these models have lead to the understanding that persistent antigen exposure in the intestinal lumen, in combination with loss of epithelial barrier function, and dysfunction and dysregulation of the innate and adaptive immune responses lead to chronic intestinal inflammation. Transcriptional changes in this environment leading to cell survival, hyperplasia, promotion of angiogenesis, persistent DNA damage, or insufficient repair of DNA damage due to an excess of proinflammatory mediators are then thought to lead to sustained malignant transformation. With regards

  19. The Szekeres Swiss Cheese model and the CMB observations

    Science.gov (United States)

    Bolejko, Krzysztof

    2009-08-01

    This paper presents the application of the Szekeres Swiss Cheese model to the analysis of observations of the cosmic microwave background (CMB) radiation. The impact of inhomogeneous matter distribution on the CMB observations is in most cases studied within the linear perturbations of the Friedmann model. However, since the density contrast and the Weyl curvature within the cosmic structures are large, this issue is worth studying using another approach. The Szekeres model is an inhomogeneous, non-symmetrical and exact solution of the Einstein equations. In this model, light propagation and matter evolution can be exactly calculated, without such approximations as small amplitude of the density contrast. This allows to examine in more realistic manner the contribution of the light propagation effect to the measured CMB temperature fluctuations. The results of such analysis show that small-scale, non-linear inhomogeneities induce, via Rees-Sciama effect, temperature fluctuations of amplitude 10-7-10-5 on angular scale ϑ 750). This is still much smaller than the measured temperature fluctuations on this angular scale. However, local and uncompensated inhomogeneities can induce temperature fluctuations of amplitude as large as 10-3, and thus can be responsible the low multipoles anomalies observed in the angular CMB power spectrum.

  20. Observational constraints on new generalized Chaplygin gas model

    CERN Document Server

    Liao, Kai; Zhu, Zong-Hong

    2012-01-01

    We use the latest data to investigate observational constraints on the new generalized Chaplygin gas (NGCG) model. Using the Markov Chain Monte Carlo (MCMC) method, we constrain the NGCG model with the type Ia supernovae (SNe Ia) from Union2 set (557 data), the usual baryonic acoustic oscillation (BAO) observation from the spectroscopic Sloan Digital Sky Survey (SDSS) data release 7 (DR7) galaxy sample, the cosmic microwave background (CMB) observation from the 7-year Wilkinson Microwave Anisotropy Probe (WMAP7) results, the newly revised $H(z)$ data, as well as a value of $\\theta_{BAO} (z=0.55) = (3.90 \\pm 0.38)^{\\circ}$ for the angular BAO scale. The constraint results for NGCG model are $\\omega_X = -1.0510_{-0.1685}^{+0.1563}(1\\sigma)_{-0.2398}^{+0.2226}(2\\sigma)$, $\\eta = 1.0117_{-0.0502}^{+0.0469}(1\\sigma)_{-0.0716}^{+0.0693}(2\\sigma)$, and $\\Omega_X = 0.7297_{-0.0276}^{+0.0229}(1\\sigma)_{-0.0402}^{+0.0329}(2\\sigma)$, which give a rather stringent constraint. From the results, we can see a phantom model ...

  1. Comparing theoretical models of our galaxy with observations

    Directory of Open Access Journals (Sweden)

    Johnston K.V.

    2012-02-01

    Full Text Available With the advent of large scale observational surveys to map out the stars in our galaxy, there is a need for an efficient tool to compare theoretical models of our galaxy with observations. To this end, we describe here the code Galaxia, which uses efficient and fast algorithms for creating a synthetic survey of the Milky Way, and discuss its uses. Given one or more observational constraints like the color-magnitude bounds, a survey size and geometry, Galaxia returns a catalog of stars in accordance with a given theoretical model of the Milky Way. Both analytic and N-body models can be sampled by Galaxia. For N-body models, we present a scheme that disperses the stars spawned by an N-body particle, in such a way that the phase space density of the spawned stars is consistent with that of the N-body particles. The code is ideally suited to generating synthetic data sets that mimic near future wide area surveys such as GAIA, LSST and HERMES. In future, we plan to release the code publicly at http://galaxia.sourceforge.net. As an application of the code, we study the prospect of identifying structures in the stellar halo with future surveys that will have velocity information about the stars.

  2. Observational constraints on the new generalized Chaplygin gas model

    Institute of Scientific and Technical Information of China (English)

    Kai Liao; Yu Pan; Zong-Hong Zhu

    2013-01-01

    We use the latest data to investigate observational constraints on the new generalized Chaplygin gas (NGCG) model.Using the Markov Chain Monte Carlo method,we constrain the NGCG model with type Ⅰa supernovae from the Union2 set (557 data),the usual baryonic acoustic oscillation (BAO) observation from the spectroscopic Sloan Digital Sky Survey data release 7 galaxy sample,the cosmic microwave background observation from the 7-year Wilkinson Microwave Anisotropy Probe results,newly revised data on H(z),as well as a value of θBAO (z =0.55) =(3.90° ± 0.38°) for the angular BAO scale.The constraint results for the NGCG model are ωx=-1.0510(-0.1685)(+0.1563)(1σ)(-0.2398)(+0.2226)(2σ),η=1.0117(-0.0502)(+0.0469)(1σ)(-0.0716)(+0.0693)(2σ) and Ωx=0.7297(-0.0276)(+0.0229)(1σ)(-0.0402)(+0.0329)(2σ),which give a rather stringent constraint.From the results,we can see that a phantom model is slightly favored and the proba-bility that energy transfers from dark matter to dark energy is a little larger than the inverse.

  3. Observations of CMEs and Models of the Eruptive Corona

    Science.gov (United States)

    Gopalswamy, Nat

    2012-01-01

    It is now realized that coronal mass ejections (CMEs) are the most energetic phenomenon in the heliosphere. Although early observations (in the 1970s and 19805) revealed most of the properties of CMEs, it is the extended and uniform data set from the Solar and Heliospheric Observatory (SOHO) mission that helped us consolidate our knowledge on CMEs. The Solar Terrestrial Relations Observatory (STEREO) mission has provided direct confirmation of the three-dimensional structure of CMEs. The broadside view provided by the STEREO coronagraphs helped us estimate the width of the halo CMEs and hence validate CME cone models. Current theoretical ideas on the internal structure of CMEs suggest that a flux rope is central to the CME structure, which has considerable observational support both from remote-sensing and in-situ observations. The flux-rope nature is also consistent with the post-eruption arcades with high-temperature plasma and the charge states observed within CMEs arriving at Earth. The quadrature observations also helped us understand the relation between the radial and expansion speeds of CMEs, which were only known from empirical relations in the past. This paper highlights some of these results obtained during solar cycle 23 and 24 and discusses implications for CME models.

  4. Alternative Energy Lessons in Scotland

    Science.gov (United States)

    Boyle, Julie

    2010-05-01

    In Scotland the new science curriculum for pupils aged 12 to 15 shall include the following outcomes: "Using my knowledge and understanding, I can express an informed view on a national or global environmental issue;" "I have participated in constructing a model to harness a renewable source of energy and can investigate how to optimise the output;" and "I can discuss why it is important to me and to the future of the world that alternatives to fossil fuels are developed." There will be an emphasis on creating lessons that will nurture responsible citizens, improve pupil engagement and allow students to develop their team working skills. To help teachers plan lessons to address this, the Scottish Schools Equipment Research Centre and Edinburgh University made teaching materials on four renewable energy resources. This poster describes how their suggested activities on solar cells, wind turbines, hydroelectric power stations and wave power were used in science lessons with twelve year old students. After an initial class discussion based on issues related to climate change and diminishing fossil fuel supplies, a workshop activity was carried out in three stages. The students were issued with a fact sheet about one of four imaginary islands (Skisdale, Cloudy Island, Surfsville and Sun City) and they were asked to work in teams to choose the most suitable method of generating electricity for their island. Issues such as costs, where it will be sited and environmental implications were considered. They were then asked to conduct practical activities by constructing and testing models for these forms of renewable energy. To conclude, they presented their proposal to the rest of the class with reasoned explanations. The kits used in the lessons can be purchased from Anderson Scientific (sales@andersonscientific.co.uk). The solar cells were simply connected to a voltmeter. The wind and hydroelectric groups used the same basic equipment. This was made using a small water

  5. A Multihit Model: Colitis Lessons from the Interleukin-10–deficient Mouse

    Science.gov (United States)

    Keubler, Lydia M.; Buettner, Manuela; Häger, Christine

    2015-01-01

    Abstract: Complex mechanisms are pulling the strings to initiate the development of inflammatory bowel disease. Current evidence indicates that an interaction of genetic susceptibilities (polymorphisms), environmental factors, and the host microbiota leads to a dysregulation of the mucosal immune system. In the past decades, the interleukin-10–deficient mouse has served as an excellent model to mirror the multifactorial nature of this disease. Here, we want to review in detail the interplay of the genetic factors, immune aspects, and especially summarize and discuss the role of the microbiota contributing to colitis development in the interleukin-10–deficient mouse model of inflammatory bowel disease as a multihit model. PMID:26164667

  6. Networking Sensor Observations, Forecast Models & Data Analysis Tools

    Science.gov (United States)

    Falke, S. R.; Roberts, G.; Sullivan, D.; Dibner, P. C.; Husar, R. B.

    2009-12-01

    This presentation explores the interaction between sensor webs and forecast models and data analysis processes within service oriented architectures (SOA). Earth observation data from surface monitors and satellite sensors and output from earth science models are increasingly available through open interfaces that adhere to web standards, such as the OGC Web Coverage Service (WCS), OGC Sensor Observation Service (SOS), OGC Web Processing Service (WPS), SOAP-Web Services Description Language (WSDL), or RESTful web services. We examine the implementation of these standards from the perspective of forecast models and analysis tools. Interoperable interfaces for model inputs, outputs, and settings are defined with the purpose of connecting them with data access services in service oriented frameworks. We review current best practices in modular modeling, such as OpenMI and ESMF/Mapl, and examine the applicability of those practices to service oriented sensor webs. In particular, we apply sensor-model-analysis interfaces within the context of wildfire smoke analysis and forecasting scenario used in the recent GEOSS Architecture Implementation Pilot. Fire locations derived from satellites and surface observations and reconciled through a US Forest Service SOAP web service are used to initialize a CALPUFF smoke forecast model. The results of the smoke forecast model are served through an OGC WCS interface that is accessed from an analysis tool that extract areas of high particulate matter concentrations and a data comparison tool that compares the forecasted smoke with Unattended Aerial System (UAS) collected imagery and satellite-derived aerosol indices. An OGC WPS that calculates population statistics based on polygon areas is used with the extract area of high particulate matter to derive information on the population expected to be impacted by smoke from the wildfires. We described the process for enabling the fire location, smoke forecast, smoke observation, and

  7. Some observational tests of a minimal galaxy formation model

    Science.gov (United States)

    Cohn, J. D.

    2017-04-01

    Dark matter simulations can serve as a basis for creating galaxy histories via the galaxy-dark matter connection. Here, one such model by Becker is implemented with several variations on three different dark matter simulations. Stellar mass and star formation rates are assigned to all simulation subhaloes at all times, using subhalo mass gain to determine stellar mass gain. The observational properties of the resulting galaxy distributions are compared to each other and observations for a range of redshifts from 0 to 2. Although many of the galaxy distributions seem reasonable, there are noticeable differences as simulations, subhalo mass gain definitions or subhalo mass definitions are altered, suggesting that the model should change as these properties are varied. Agreement with observations may improve by including redshift dependence in the added-by-hand random contribution to star formation rate. There appears to be an excess of faint quiescent galaxies as well (perhaps due in part to differing definitions of quiescence). The ensemble of galaxy formation histories for these models tend to have more scatter around their average histories (for a fixed final stellar mass) than the two more predictive and elaborate semi-analytic models of Guo et al. and Henriques et al., and require more basis fluctuations (using principal component analysis) to capture 90 per cent of the scatter around their average histories. The codes to plot model predictions (in some cases alongside observational data) are publicly available to test other mock catalogues at https://github.com/jdcphysics/validation/. Information on how to use these codes is in Appendix A.

  8. Quantitative comparisons of satellite observations and cloud models

    Science.gov (United States)

    Wang, Fang

    Microwave radiation interacts directly with precipitating particles and can therefore be used to compare microphysical properties found in models with those found in nature. Lower frequencies (minimization procedures but produce different CWP and RWP. The similarity in Tb can be attributed to comparable Total Water Path (TWP) between the two retrievals while the disagreement in the microphysics is caused by their different degrees of constraint of the cloud/rain ratio by the observations. This situation occurs frequently and takes up 46.9% in the one month 1D-Var retrievals examined. To attain better constrained cloud/rain ratios and improved retrieval quality, this study suggests the implementation of higher microwave frequency channels in the 1D-Var algorithm. Cloud Resolving Models (CRMs) offer an important pathway to interpret satellite observations of microphysical properties of storms. High frequency microwave brightness temperatures (Tbs) respond to precipitating-sized ice particles and can, therefore, be compared with simulated Tbs at the same frequencies. By clustering the Tb vectors at these frequencies, the scene can be classified into distinct microphysical regimes, in other words, cloud types. The properties for each cloud type in the simulated scene are compared to those in the observation scene to identify the discrepancies in microphysics within that cloud type. A convective storm over the Amazon observed by the Tropical Rainfall Measuring Mission (TRMM) is simulated using the Regional Atmospheric Modeling System (RAMS) in a semi-ideal setting, and four regimes are defined within the scene using cluster analysis: the 'clear sky/thin cirrus' cluster, the 'cloudy' cluster, the 'stratiform anvil' cluster and the 'convective' cluster. The relationship between Tb difference of 37 and 85 GHz and Tb at 85 GHz is found to contain important information of microphysical properties such as hydrometeor species and size distributions. Cluster

  9. Adjoint inversion modeling of Asian dust emission using lidar observations

    Directory of Open Access Journals (Sweden)

    K. Yumimoto

    2008-06-01

    Full Text Available A four-dimensional variational (4D-Var data assimilation system for a regional dust model (RAMS/CFORS-4DVAR; RC4 is applied to an adjoint inversion of a heavy dust event over eastern Asia during 20 March–4 April 2007. The vertical profiles of the dust extinction coefficients derived from NIES Lidar network are directly assimilated, with validation using observation data. Two experiments assess impacts of observation site selection: Experiment A uses five Japanese observation sites located downwind of dust source regions; Experiment B uses these and two other sites near source regions. Assimilation improves the modeled dust extinction coefficients. Experiment A and Experiment B assimilation results are mutually consistent, indicating that observations of Experiment A distributed over Japan can provide comprehensive information related to dust emission inversion. Time series data of dust AOT calculated using modeled and Lidar dust extinction coefficients improve the model results. At Seoul, Matsue, and Toyama, assimilation reduces the root mean square differences of dust AOT by 35–40%. However, at Beijing and Tsukuba, the RMS differences degrade because of fewer observations during the heavy dust event. Vertical profiles of the dust layer observed by CALIPSO are compared with assimilation results. The dense dust layer was trapped at potential temperatures (θ of 280–300 K and was higher toward the north; the model reproduces those characteristics well. Latitudinal distributions of modeled dust AOT along the CALIPSO orbit paths agree well with those of CALIPSO dust AOT, OMI AI, and MODIS coarse-mode AOT, capturing the latitude at which AOTs and AI have high values. Assimilation results show increased dust emissions over the Gobi Desert and Mongolia; especially for 29–30 March, emission flux is about 10 times greater. Strong dust uplift fluxes over the Gobi Desert and Mongolia cause the heavy dust event. Total optimized dust emissions are 57

  10. Solar spectral irradiance variability in cycle 24: observations and models

    Directory of Open Access Journals (Sweden)

    Marchenko Sergey V.

    2016-01-01

    Full Text Available Utilizing the excellent stability of the Ozone Monitoring Instrument (OMI, we characterize both short-term (solar rotation and long-term (solar cycle changes of the solar spectral irradiance (SSI between 265 and 500 nm during the ongoing cycle 24. We supplement the OMI data with concurrent observations from the Global Ozone Monitoring Experiment-2 (GOME-2 and Solar Radiation and Climate Experiment (SORCE instruments and find fair-to-excellent, depending on wavelength, agreement among the observations, and predictions of the Naval Research Laboratory Solar Spectral Irradiance (NRLSSI2 and Spectral And Total Irradiance REconstruction for the Satellite era (SATIRE-S models.

  11. Your Vision or My Model? Lessons from Participatory Land Use Scenario Development on a European Scale

    DEFF Research Database (Denmark)

    Volkery, Axel; Ribeiro, Teresa; Henrichs, Thomas;

    2008-01-01

    Participatory processes in scenario development have received increasing attention throughout the last years. Combining qualitative stakeholder and quantitative expert information (i.e. modelling) offers unique opportunities to mix good data, scientific rigour, imagination and expertise from...

  12. Why technical trading may be successful? A lesson from the agent-based modeling

    Science.gov (United States)

    Schmidt, Anatoly B.

    2002-01-01

    It is shown using a simple agent-based market dynamics model that if the technical traders are able to affect the market liquidity, their concerted actions can move the market price in the direction favorable to their strategy.

  13. Progress of clinical practice on the management of burn-associated pain: Lessons from animal models.

    Science.gov (United States)

    McIntyre, Matthew K; Clifford, John L; Maani, Christopher V; Burmeister, David M

    2016-09-01

    Opioid-based analgesics provide the mainstay for attenuating burn pain, but they have a myriad of side effects including respiratory depression, nausea, impaired gastrointestinal motility, sedation, dependence, physiologic tolerance, and opioid-induced hyperalgesia. To test and develop novel analgesics, validated burn-relevant animal models of pain are indispensable. Herein we review such animal models, which are mostly limited to rodent models of burn-induced, inflammatory, and neuropathic pain. The latter two are pain syndromes that provide insight into the pain caused by systemic pro-inflammatory cytokines and direct injury to nerves (e.g., after severe burn), respectively. To date, no single animal model optimally mimics the complex pathophysiology and pain that a human burn patient experiences. No currently available burn-pain model examines effects of pharmacological intervention on wound healing. As cornerstones of pain and wound healing, pro-inflammatory mediators may be utilized for insight into both processes. Moreover, common clinical concerns such as systemic inflammatory response syndrome and multiple organ dysfunction remain unaddressed. For development of analgesics, these aberrations can significantly alter the potential efficacy and/or adverse effects of a prescribed analgesic following burn trauma. We therefore suggest that a multi-model strategy would be the most clinically relevant when evaluating novel analgesics for use in burn patients.

  14. Inductive reasoning in medicine: lessons from Carl Gustav Hempel's 'inductive-statistical' model.

    Science.gov (United States)

    Gandjour, Afschin; Lauterbach, Karl Wilhelm

    2003-05-01

    The purpose of this paper is to discuss both the fundamental requirements of sound scientific explanations and predictions and common fallacies that occur in explaining and predicting medical problems. To this end, the paper presents Carl Gustav Hempel's 'covering-law' model (1948 and 1962) and reviews some of the criticism of the model. The strength of Hempel's model is that it shows that inductive arguments, when applied with the requirement of maximal specificity, can serve as explanations as well as predictions. The major weakness of the 'covering-law' model, its inability to portray causal relatedness, has been addressed by philosophers such as Wesley Salmon. While few philosophers today agree with the 'covering-law' model in its original formulation, there is widespread consensus that the law has made a central contribution to describing the fundamental requirements of sound scientific explanations. Applying this model and its revisions in the medical context may help uncover potentially undetected fallacies in reasoning when explaining and predicting medical problems.

  15. Observations and modeling of a tidal inlet dye tracer plume

    Science.gov (United States)

    Feddersen, Falk; Olabarrieta, Maitane; Guza, R. T.; Winters, D.; Raubenheimer, Britt; Elgar, Steve

    2016-10-01

    A 9 km long tracer plume was created by continuously releasing Rhodamine WT dye for 2.2 h during ebb tide within the southern edge of the main tidal channel at New River Inlet, NC on 7 May 2012, with highly obliquely incident waves and alongshore winds. Over 6 h from release, COAWST (coupled ROMS and SWAN, including wave, wind, and tidal forcing) modeled dye compares well with (aerial hyperspectral and in situ) observed dye concentration. Dye first was transported rapidly seaward along the main channel and partially advected across the ebb-tidal shoal until reaching the offshore edge of the shoal. Dye did not eject offshore in an ebb-tidal jet because the obliquely incident breaking waves retarded the inlet-mouth ebb-tidal flow and forced currents along the ebb shoal. The dye plume largely was confined to <4 m depth. Dye was then transported downcoast in the narrow (few 100 m wide) surfzone of the beach bordering the inlet at 0.3 m s-1 driven by wave breaking. Over 6 h, the dye plume is not significantly affected by buoyancy. Observed dye mass balances close indicating all released dye is accounted for. Modeled and observed dye behaviors are qualitatively similar. The model simulates well the evolution of the dye center of mass, lateral spreading, surface area, and maximum concentration, as well as regional ("inlet" and "ocean") dye mass balances. This indicates that the model represents well the dynamics of the ebb-tidal dye plume. Details of the dye transport pathways across the ebb shoal are modeled poorly perhaps owing to low-resolution and smoothed model bathymetry. Wave forcing effects have a large impact on the dye transport.

  16. New Cosmological Model and Its Implications on Observational Data Interpretation

    Directory of Open Access Journals (Sweden)

    Vlahovic Branislav

    2013-09-01

    Full Text Available The paradigm of ΛCDM cosmology works impressively well and with the concept of inflation it explains the universe after the time of decoupling. However there are still a few concerns; after much effort there is no detection of dark matter and there are significant problems in the theoretical description of dark energy. We will consider a variant of the cosmological spherical shell model, within FRW formalism and will compare it with the standard ΛCDM model. We will show that our new topological model satisfies cosmological principles and is consistent with all observable data, but that it may require new interpretation for some data. Considered will be constraints imposed on the model, as for instance the range for the size and allowed thickness of the shell, by the supernovae luminosity distance and CMB data. In this model propagation of the light is confined along the shell, which has as a consequence that observed CMB originated from one point or a limited space region. It allows to interpret the uniformity of the CMB without inflation scenario. In addition this removes any constraints on the uniformity of the universe at the early stage and opens a possibility that the universe was not uniform and that creation of galaxies and large structures is due to the inhomogeneities that originated in the Big Bang.

  17. A sliding mode observer for hemodynamic characterization under modeling uncertainties

    KAUST Repository

    Zayane, Chadia

    2014-06-01

    This paper addresses the case of physiological states reconstruction in a small region of the brain under modeling uncertainties. The misunderstood coupling between the cerebral blood volume and the oxygen extraction fraction has lead to a partial knowledge of the so-called balloon model describing the hemodynamic behavior of the brain. To overcome this difficulty, a High Order Sliding Mode observer is applied to the balloon system, where the unknown coupling is considered as an internal perturbation. The effectiveness of the proposed method is illustrated through a set of synthetic data that mimic fMRI experiments.

  18. Constraining interacting dark energy models with latest cosmological observations

    Science.gov (United States)

    Xia, Dong-Mei; Wang, Sai

    2016-11-01

    The local measurement of H0 is in tension with the prediction of Λ cold dark matter model based on the Planck data. This tension may imply that dark energy is strengthened in the late-time Universe. We employ the latest cosmological observations on cosmic microwave background, the baryon acoustic oscillation, large-scale structure, supernovae, H(z) and H0 to constrain several interacting dark energy models. Our results show no significant indications for the interaction between dark energy and dark matter. The H0 tension can be moderately alleviated, but not totally released.

  19. Constraining interacting dark energy models with latest cosmological observations

    CERN Document Server

    Xia, Dong-Mei

    2016-01-01

    The local measurement of $H_0$ is in tension with the prediction of $\\Lambda$CDM model based on the Planck data. This tension may imply that dark energy is strengthened in the late-time Universe. We employ the latest cosmological observations on CMB, BAO, LSS, SNe, $H(z)$ and $H_0$ to constrain several interacting dark energy models. Our results show no significant indications for the interaction between dark energy and dark matter. The $H_0$ tension can be moderately alleviated, but not totally released.

  20. Altitude dependence of atmospheric temperature trends: Climate models versus observation

    CERN Document Server

    Douglass, D H; Singer, F

    2004-01-01

    As a consequence of greenhouse forcing, all state of the art general circulation models predict a positive temperature trend that is greater for the troposphere than the surface. This predicted positive trend increases in value with altitude until it reaches a maximum ratio with respect to the surface of as much as 1.5 to 2.0 at about 200 to 400 hPa. However, the temperature trends from several independent observational data sets show decreasing as well as mostly negative values. This disparity indicates that the three models examined here fail to account for the effects of greenhouse forcings.

  1. The s Process: Nuclear Physics, Stellar Models, Observations

    CERN Document Server

    Kaeppeler, Franz; Bisterzo, Sara; Aoki, Wako

    2010-01-01

    Nucleosynthesis in the s process takes place in the He burning layers of low mass AGB stars and during the He and C burning phases of massive stars. The s process contributes about half of the element abundances between Cu and Bi in solar system material. Depending on stellar mass and metallicity the resulting s-abundance patterns exhibit characteristic features, which provide comprehensive information for our understanding of the stellar life cycle and for the chemical evolution of galaxies. The rapidly growing body of detailed abundance observations, in particular for AGB and post-AGB stars, for objects in binary systems, and for the very faint metal-poor population represents exciting challenges and constraints for stellar model calculations. Based on updated and improved nuclear physics data for the s-process reaction network, current models are aiming at ab initio solution for the stellar physics related to convection and mixing processes. Progress in the intimately related areas of observations, nuclear...

  2. The solar dynamo: inferences from observations and modeling

    CERN Document Server

    Kitchatinov, L L

    2014-01-01

    It can be shown on observational grounds that two basic effects of dynamo theory for solar activity - production of the toroidal field from the poloidal one by differential rotation and reverse conversion of the toroidal field to the poloidal configuration by helical motions - are operating in the Sun. These two effects, however, do not suffice for constructing a realistic model for the solar dynamo. Only when a non-local version of the alpha-effect is applied, is downward diamagnetic pumping included and field advection by the equatorward meridional flow near the base of the convection zone allowed for, can the observed activity cycles be closely reproduced. Fluctuations in the alpha-effect can be estimated from sunspot data. Dynamo models with fluctuating parameters reproduce irregularities of solar cycles including the grand activity minima. The physics of parametric excitation of irregularities remains, however, to be understood.

  3. Seismicity induced by CO2 injection: lesson learned from coupled hydro-mechanical modeling

    Science.gov (United States)

    Rinaldi, Antonio Pio; Rutqvist, Jonny; Urpi, Luca; Cappa, Frederic; Jeanne, Pierre; Vilarrasa, Victor

    2017-04-01

    Overpressure caused by the direct injection of CO2 into a deep sedimentary system may produce changes in the state of stress, as well as, have an impact on the sealing capabilities of the targeted system. The importance of geomechanics including the potential for reactivating faults associated with large-scale geologic carbon sequestration operations has recently become more widely recognized. In this context, here we review and summarize some recent modeling efforts, aimed at understanding the possible seismicity induced by CO2 storage and its relation to potential leakage to shallow groundwater aquifer during active injection. The simulations were conducted using TOUGH-FLAC, a simulator for coupled multiphase flow and geomechanical modeling. We carried out both quasi-static and dynamic simulations, with an explicit representation of a fault. In the case of quasi-static modeling, a strain softening Mohr-Coulomb model was used to model a slip-weakening fault slip behavior, enabling modeling of sudden slip that was interpreted as a seismic event, with a moment magnitude evaluated using formulas from seismology. In the case of dynamic modeling, we simulate the fault behavior as strain-softening or rate-dependent, analyzing the frequency behavior at surface and the possible effects of friction properties on slip. This work aims at studying the fault responses during carbon dioxide injection, focusing on the short-term (5 years) integrity of the storage repository, and hence, on the potential leakage towards shallow groundwater aquifers. We account for stress/strain-dependent permeability and study both the fault reactivation and the leakage through the fault zone. We analyze several scenarios related to the injected amount of CO2 (and hence related to potential overpressure) involving both minor and major faults, and study induced seismicity and leakage for different stress/strain permeability coupling functions, as well as increasing the complexity of the system in

  4. Seeing about Soil -- Management Lessons from a Simple Model for Renewable Resources

    CERN Document Server

    Lichtenegger, Klaus

    2013-01-01

    Employing an effective cellular automata model, we investigate and analyze the build-up and erosion of soil. Depending on the strategy employed for handling agricultural production, in many cases we find a critical dependence on the prescribed production target, with a sharp transition between stable production and complete breakdown of the system. Strategies which are particularly well-suited for mimicking real-world management approaches can produce almost cyclic behaviour, which can also either lead to sustainable production or to breakdown. While designed to describe the dynamics of soil evolution, this model is quite general and may also be useful as a model for other renewable resources and may even be employed in other disciplines like psychology.

  5. Observations, Thermochemical Calculations, and Modeling of Exoplanetary Atmospheres

    CERN Document Server

    Blecic, Jasmina

    2016-01-01

    This dissertation as a whole aims to provide means to better understand hot-Jupiter planets through observing, performing thermochemical calculations, and modeling their atmospheres. We used Spitzer multi-wavelength secondary-eclipse observations and targets with high signal-to-noise ratios, as their deep eclipses allow us to detect signatures of spectral features and assess planetary atmospheric structure and composition with greater certainty. Chapter 1 gives a short introduction. Chapter 2 presents the Spitzer secondary-eclipse analysis and atmospheric characterization of WASP-14b. WASP-14b is a highly irradiated, transiting hot Jupiter. By applying a Bayesian approach in the atmospheric analysis, we found an absence of thermal inversion contrary to theoretical predictions. Chapter 3 describes the infrared observations of WASP-43b Spitzer secondary eclipses, data analysis, and atmospheric characterization. WASP-43b is one of the closest-orbiting hot Jupiters, orbiting one of the coolest stars with a hot Ju...

  6. Mock Observations of Blue Stragglers in Globular Cluster Models

    CERN Document Server

    Sills, Alison; Chatterjee, Sourav; Rasio, Frederic A

    2013-01-01

    We created artificial color-magnitude diagrams of Monte Carlo dynamical models of globular clusters, and then used observational methods to determine the number of blue stragglers in those clusters. We compared these blue stragglers to various cluster properties, mimicking work that has been done for blue stragglers in Milky Way globular clusters to determine the dominant formation mechanism(s) of this unusual stellar population. We find that a mass-based prescription for selecting blue stragglers will choose approximately twice as many blue stragglers than a selection criterion that was developed for observations of real clusters. However, the two numbers of blue stragglers are well-correlated, so either selection criterion can be used to characterize the blue straggler population of a cluster. We confirm previous results that the simplified prescription for the evolution of a collision or merger product in the BSE code overestimates the lifetime of collision products. Because our observationally-motivated s...

  7. Observational & modeling analysis of surface heat and moisture fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Smith, E. [Florida State Univ., Tallahassee, FL (United States)

    1995-09-01

    An observational and modeling study was conducted to help assess how well current GCMs are predicting surface fluxes under the highly variable cloudiness and flow conditions characteristic of the real atmosphere. The observational data base for the study was obtained from a network of surface flux stations operated during the First ISLSCP Field Experiment (FIFE). The study included examination of a surface-driven secondary circulation in the boundary layer resulting from a persistent cross-site gradient in soil moisture, to demonstrate the sensitivity of boundary layer dynamics to heterogeneous surface fluxes, The performance of a biosphere model in reproducing the measured surface fluxes was evaluated with and without the use of satellite retrieval of three key canopy variables with RMS uncertainties commensurate with those of the measurements themselves. Four sensible heat flux closure schemes currently being used in GCMs were then evaluated against the FIFE observations. Results indicate that the methods by which closure models are calibrated lead to exceedingly large errors when the schemes are applied to variable boundary layer conditions. 4 refs., 2 figs.

  8. Coronal Loops: Observations and Modeling of Confined Plasma

    Directory of Open Access Journals (Sweden)

    Fabio Reale

    2014-07-01

    Full Text Available Coronal loops are the building blocks of the X-ray bright solar corona. They owe their brightness to the dense confined plasma, and this review focuses on loops mostly as structures confining plasma. After a brief historical overview, the review is divided into two separate but not independent parts: the first illustrates the observational framework, the second reviews the theoretical knowledge. Quiescent loops and their confined plasma are considered and, therefore, topics such as loop oscillations and flaring loops (except for non-solar ones, which provide information on stellar loops are not specifically addressed here. The observational section discusses the classification, populations, and the morphology of coronal loops, its relationship with the magnetic field, and the loop stranded structure. The section continues with the thermal properties and diagnostics of the loop plasma, according to the classification into hot, warm, and cool loops. Then, temporal analyses of loops and the observations of plasma dynamics, hot and cool flows, and waves are illustrated. In the modeling section, some basics of loop physics are provided, supplying fundamental scaling laws and timescales, a useful tool for consultation. The concept of loop modeling is introduced and models are divided into those treating loops as monolithic and static, and those resolving loops into thin and dynamic strands. More specific discussions address modeling the loop fine structure and the plasma flowing along the loops. Special attention is devoted to the question of loop heating, with separate discussion of wave (AC and impulsive (DC heating. Large-scale models including atmosphere boxes and the magnetic field are also discussed. Finally, a brief discussion about stellar coronal loops is followed by highlights and open questions.

  9. Successful aging as a continuum of functional independence: lessons from physical disability models of aging.

    NARCIS (Netherlands)

    Lowry, K.A.; Vallejo, A.N.; Studenski, S.A.

    2012-01-01

    Successful aging is a multidimensional construct that could be viewed as a continuum of achievement. Based on the disability model proposed by the WHO International Classification of Functioning, Disability and Health, successful aging includes not only the presence or absence of disease, but also

  10. Modelling the Labour Market for Teachers: Some Lessons from the UK.

    Science.gov (United States)

    Dolton, Peter

    1996-01-01

    Describes an econometric modeling of the labor market for teachers in an "administered" market setting in which the government partially controls the main determinants of demand and is very influential in setting teachers' wages. Reviews relevant econometric literature and shows market forces' crucial role. Discusses economic policy…

  11. Breaking the Patriarchal Vision of Social Science: Lessons from a Family Therapy Model.

    Science.gov (United States)

    McNamee, Sheila

    The Milan model of systemic family therapy, developed in Italy and based on G. Bateson's cybernetic epistemology, can help meet the goals of a feminist/systemic epistemology in research by accepting data in its "traditional" form yet also connecting it to the act of researching, itself, thereby merging a feminist perspective with the…

  12. Pattern-oriented modeling of agent-based complex systems: lessons from ecology

    NARCIS (Netherlands)

    Grimm, V.; Revilla, E.; Berger, U.; Jeltsch, F.; Mooij, W.M.; Railsback, S.F.; Thulke, H-H.; Weiner, J.; Wiegand, T.; DeAngelis, D.L.

    2005-01-01

    Agent-based complex systems are dynamic networks of many interacting agents; examples include ecosystems, financial markets, and cities. The search for general principles underlying the internal organization of such systems often uses bottom-up simulation models such as cellular automata and agent-b

  13. Development of new pharmacological agents for epilepsy: lessons from the kindling model.

    Science.gov (United States)

    McNamara, J O

    1989-01-01

    The greatest value of the kindling model for new therapy of epilepsy almost certainly lies in elucidating the molecular basis of its development and persistence. Such an understanding may provide a foundation for therapies aimed at prevention or perhaps even cure of some forms of human epilepsy.

  14. Hepatic steatosis : A mediator of the metabolic syndrome. Lessons from animal models

    NARCIS (Netherlands)

    den Boer, M; Voshol, PJ; Kuipers, F; Havekes, LM; Romijn, JA

    2004-01-01

    Epidemiological studies in humans, as well as experimental studies in animal models, have shown an association between visceral obesity and dyslipidemia, insulin resistance, and type 2 diabetes mellitus. Recently, attention has been focused on the excessive accumulation of triglycerides (TG) in the

  15. Lessons Learned Coaching Teachers in Behavior Management: The PBIS"plus" Coaching Model

    Science.gov (United States)

    Hershfeldt, Patricia A.; Pell, Karen; Sechrest, Richard; Pas, Elise T.; Bradshaw, Catherine P.

    2012-01-01

    There is growing interest in coaching as a means of promoting professional development and the use of evidence-based practices in schools. This article describes the PBIS"plus" coaching model used to provide technical assistance for classroom- and school-wide behavior management to elementary schools over the course of 3 years. This Tier…

  16. Modelling the Labour Market for Teachers: Some Lessons from the UK.

    Science.gov (United States)

    Dolton, Peter

    1996-01-01

    Describes an econometric modeling of the labor market for teachers in an "administered" market setting in which the government partially controls the main determinants of demand and is very influential in setting teachers' wages. Reviews relevant econometric literature and shows market forces' crucial role. Discusses economic policy implications…

  17. Regional Policy Models for Forest Biodiversity Analysis: Lessons From Coastal Oregon

    Science.gov (United States)

    K. Norman Johnson; Sally Duncan; Thomas A. Spies

    2007-01-01

    The crisis in the early 1990s over conservation of biodiversity in the forests of the Pacific Northwest caused an upheaval in forest policies for public and private landowners. These events led to the development of the Coastal Landscape Assessment and Modeling Study (CLAMS) for the Coast Range Physiographic Province of Oregon, a province containing over two million...

  18. Successful aging as a continuum of functional independence: lessons from physical disability models of aging.

    NARCIS (Netherlands)

    Lowry, K.A.; Vallejo, A.N.; Studenski, S.A.

    2012-01-01

    Successful aging is a multidimensional construct that could be viewed as a continuum of achievement. Based on the disability model proposed by the WHO International Classification of Functioning, Disability and Health, successful aging includes not only the presence or absence of disease, but also a

  19. 3D Modeling and Printing in History/Social Studies Classrooms: Initial Lessons and Insights

    Science.gov (United States)

    Maloy, Robert; Trust, Torrey; Kommers, Suzan; Malinowski, Allison; LaRoche, Irene

    2017-01-01

    This exploratory study examines the use of 3D technology by teachers and students in four middle school history/social studies classrooms. As part of a university-developed 3D Printing 4 Teaching & Learning project, teachers integrated 3D modeling and printing into curriculum topics in world geography, U.S. history, and government/civics.…

  20. Lessons from Mr. Larson: An Inductive Model of Teaching for Orchestrating Discourse

    Science.gov (United States)

    Truxaw, Mary P.; DeFranco, Thomas C.

    2007-01-01

    The National Council of Teachers of Mathematics (NCTM) has consistently recognized communication as essential to reform-oriented mathematics teaching (NCTM 1991, 2000). In this article, the authors propose a strategic mix of univocal and dialogic discourse that, when used in conjunction with an "inductive model of teaching," can promote…

  1. Lessons Learned Coaching Teachers in Behavior Management: The PBIS"plus" Coaching Model

    Science.gov (United States)

    Hershfeldt, Patricia A.; Pell, Karen; Sechrest, Richard; Pas, Elise T.; Bradshaw, Catherine P.

    2012-01-01

    There is growing interest in coaching as a means of promoting professional development and the use of evidence-based practices in schools. This article describes the PBIS"plus" coaching model used to provide technical assistance for classroom- and school-wide behavior management to elementary schools over the course of 3 years. This Tier…

  2. Educational Transformation in Upper-Division Physics: The Science Education Initiative Model, Outcomes, and Lessons Learned

    Science.gov (United States)

    Chasteen, Stephanie V.; Wilcox, Bethany; Caballero, Marcos D.; Perkins, Katherine K.; Pollock, Steven J.; Wieman, Carl E.

    2015-01-01

    In response to the need for a scalable, institutionally supported model of educational change, the Science Education Initiative (SEI) was created as an experiment in transforming course materials and faculty practices at two institutions--University of Colorado Boulder (CU) and University of British Columbia. We find that this departmentally…

  3. Pattern-oriented modeling of agent-based complex systems: lessons from ecology

    NARCIS (Netherlands)

    Grimm, V.; Revilla, E.; Berger, U.; Jeltsch, F.; Mooij, W.M.; Railsback, S.F.; Thulke, H-H.; Weiner, J.; Wiegand, T.; DeAngelis, D.L.

    2005-01-01

    Agent-based complex systems are dynamic networks of many interacting agents; examples include ecosystems, financial markets, and cities. The search for general principles underlying the internal organization of such systems often uses bottom-up simulation models such as cellular automata and

  4. Cultural Models in Communication with Infants: Lessons from Kikaikelaki, Cameroon and Muenster, Germany

    Science.gov (United States)

    Demuth, Carolin; Keller, Heidi; Yovsi, Relindis D.

    2012-01-01

    Child rearing is a universal task, yet there are differing solutions according to the dynamics of socio-cultural milieu in which children are raised. Cultural models of what is considered good or bad parenting become explicit in everyday routine practices. Focusing on early mother-infant interactions in this article we examine the discursive…

  5. An observational model for biomechanical assessment of sprint kayaking technique.

    Science.gov (United States)

    McDonnell, Lisa K; Hume, Patria A; Nolte, Volker

    2012-11-01

    Sprint kayaking stroke phase descriptions for biomechanical analysis of technique vary among kayaking literature, with inconsistencies not conducive for the advancement of biomechanics applied service or research. We aimed to provide a consistent basis for the categorisation and analysis of sprint kayak technique by proposing a clear observational model. Electronic databases were searched using key words kayak, sprint, technique, and biomechanics, with 20 sources reviewed. Nine phase-defining positions were identified within the kayak literature and were divided into three distinct types based on how positions were defined: water-contact-defined positions, paddle-shaft-defined positions, and body-defined positions. Videos of elite paddlers from multiple camera views were reviewed to determine the visibility of positions used to define phases. The water-contact-defined positions of catch, immersion, extraction, and release were visible from multiple camera views, therefore were suitable for practical use by coaches and researchers. Using these positions, phases and sub-phases were created for a new observational model. We recommend that kayaking data should be reported using single strokes and described using two phases: water and aerial. For more detailed analysis without disrupting the basic two-phase model, a four-sub-phase model consisting of entry, pull, exit, and aerial sub-phases should be used.

  6. Observer analysis and its impact on task performance modeling

    Science.gov (United States)

    Jacobs, Eddie L.; Brown, Jeremy B.

    2014-05-01

    Fire fighters use relatively low cost thermal imaging cameras to locate hot spots and fire hazards in buildings. This research describes the analyses performed to study the impact of thermal image quality on fire fighter fire hazard detection task performance. Using human perception data collected by the National Institute of Standards and Technology (NIST) for fire fighters detecting hazards in a thermal image, an observer analysis was performed to quantify the sensitivity and bias of each observer. Using this analysis, the subjects were divided into three groups representing three different levels of performance. The top-performing group was used for the remainder of the modeling. Models were developed which related image quality factors such as contrast, brightness, spatial resolution, and noise to task performance probabilities. The models were fitted to the human perception data using logistic regression, as well as probit regression. Probit regression was found to yield superior fits and showed that models with not only 2nd order parameter interactions, but also 3rd order parameter interactions performed the best.

  7. New lessons on the Sudd hydrology learned from remote sensing and climate modeling

    Directory of Open Access Journals (Sweden)

    Y. A. Mohamed

    2006-01-01

    Full Text Available Despite its local and regional importance, hydro-meteorological data on the Sudd (one of Africa's largest wetlands is very scanty. This is due to the physical and political situation of this area of Sudan. The areal size of the wetland, the evaporation rate, and the influence on the micro and meso climate are still unresolved questions of the Sudd hydrology. The evaporation flux from the Sudd wetland has been estimated using thermal infrared remote sensing data and a parameterization of the surface energy balance (SEBAL model. It is concluded that the actual spatially averaged evaporation from the Sudd wetland over 3 years of different hydrometeorological characteristics varies between 1460 and 1935 mm/yr. This is substantially less than open water evaporation. The wetland area appears to be 70% larger than previously assumed when the Sudd was considered as an open water body. The temporal analysis of the Sudd evaporation demonstrated that the variation of the atmospheric demand in combination with the inter-annual fluctuation of the groundwater table results into a quasi-constant evaporation rate in the Sudd, while open water evaporation depicts a clear seasonal variability. The groundwater table characterizes a distinct seasonality, confirming that substantial parts of the Sudd are seasonal swamps. The new set of spatially distributed evaporation parameters from remote sensing form an important dataset for calibrating a regional climate model enclosing the Nile Basin. The Regional Atmospheric Climate Model (RACMO provides an insight not only into the temporal evolution of the hydro-climatological parameters, but also into the land surface climate interactions and embedded feedbacks. The impact of the flooding of the Sudd on the Nile hydroclimatology has been analysed by simulating two land surface scenarios (with and without the Sudd wetland. The paper presents some of the model results addressing the Sudd's influence on rainfall, evaporation

  8. Observational constraints on non-minimally coupled Galileon model

    CERN Document Server

    Jamil, Mubasher; Myrzakulov, Ratbay; 10.1140/epjc/s10052-013-2300-6

    2013-01-01

    As an extension of Dvali-Gabadadze-Porrati (DGP) model, the Galileon theory has been proposed to explain the "self-accelerating problem" and "ghost instability problem". In this Paper, we extend the Galileon theory by considering a non-minimally coupled Galileon scalar with gravity. We find that crossing of phantom divide line is possible for such model. Moreover we perform the statefinder analysis and $Om(z)$ diagnostic and constraint the model parameters from the latest Union 2 type Ia Supernova (SNe Ia) set and the baryonic acoustic oscillation (BAO). Using these data sets, we obtain the constraints $\\Omega_\\text{m0}=0.263_{-0.031}^{+0.031}$, $n=1.53_{-0.37}^{+0.21}$ (at the 95% confidence level) with $\\chi^2_{\\text{min}}=473.376$. Further we study the evolution of the equation of state parameter for the effective dark energy and observe that SNe Ia + BAO prefers a phantom-like dark energy.

  9. Dealing with Power Games in a Companion Modelling Process: Lessons from Community Water Management in Thailand Highlands

    Science.gov (United States)

    Barnaud, Cecile; van Paassen, Annemarie; Trebuil, Guy; Promburom, Tanya; Bousquet, Francois

    2010-01-01

    Although stakeholder participation is expected to promote equitable and sustainable natural resource management, lessons from the past tell us that more careful attention needs to be paid to achieving equitable impacts. Now the question is how to address social inequities and power asymmetries. Some authors emphasize the need for more dialogue,…

  10. Dealing with Power Games in a Companion Modelling Process: Lessons from Community Water Management in Thailand Highlands

    Science.gov (United States)

    Barnaud, Cecile; van Paassen, Annemarie; Trebuil, Guy; Promburom, Tanya; Bousquet, Francois

    2010-01-01

    Although stakeholder participation is expected to promote equitable and sustainable natural resource management, lessons from the past tell us that more careful attention needs to be paid to achieving equitable impacts. Now the question is how to address social inequities and power asymmetries. Some authors emphasize the need for more dialogue,…

  11. Human pathogenic bacteria, fungi, and viruses in Drosophila: disease modeling, lessons, and shortcomings.

    Science.gov (United States)

    Panayidou, Stavria; Ioannidou, Eleni; Apidianakis, Yiorgos

    2014-02-15

    Drosophila has been the invertebrate model organism of choice for the study of innate immune responses during the past few decades. Many Drosophila-microbe interaction studies have helped to define innate immunity pathways, and significant effort has been made lately to decipher mechanisms of microbial pathogenesis. Here we catalog 68 bacterial, fungal, and viral species studied in flies, 43 of which are relevant to human health. We discuss studies of human pathogens in flies revealing not only the elicitation and avoidance of immune response but also mechanisms of tolerance, host tissue homeostasis, regeneration, and predisposition to cancer. Prominent among those is the emerging pattern of intestinal regeneration as a defense response induced by pathogenic and innocuous bacteria. Immunopathology mechanisms and many microbial virulence factors have been elucidated, but their relevance to human health conventionally necessitates validation in mammalian models of infection.

  12. Accounting for the kinetics in order parameter analysis: lessons from theoretical models and a disordered peptide

    CERN Document Server

    Berezovska, Ganna; Mostarda, Stefano; Rao, Francesco

    2012-01-01

    Molecular simulations as well as single molecule experiments have been widely analyzed in terms order parameters, the latter representing candidate probes for the relevant degrees of freedom. Notwithstanding this approach is very intuitive, mounting evidence showed that such description is not accurate, leading to ambiguous definitions of states and wrong kinetics. To overcome these limitations a framework making use of order parameter fluctuations in conjunction with complex network analysis is investigated. Derived from recent advances in the analysis of single molecule time traces, this approach takes into account of the fluctuations around each time point to distinguish between states that have similar values of the order parameter but different dynamics. Snapshots with similar fluctuations are used as nodes of a transition network, the clusterization of which into states provides accurate Markov-State-Models of the system under study. Application of the methodology to theoretical models with a noisy orde...

  13. Dynamo onset as a first-order transition: lessons from a shell model for magnetohydrodynamics.

    Science.gov (United States)

    Sahoo, Ganapati; Mitra, Dhrubaditya; Pandit, Rahul

    2010-03-01

    We carry out systematic and high-resolution studies of dynamo action in a shell model for magnetohydrodynamic (MHD) turbulence over wide ranges of the magnetic Prandtl number PrM and the magnetic Reynolds number ReM. Our study suggests that it is natural to think of dynamo onset as a nonequilibrium first-order phase transition between two different turbulent, but statistically steady, states. The ratio of the magnetic and kinetic energies is a convenient order parameter for this transition. By using this order parameter, we obtain the stability diagram (or nonequilibrium phase diagram) for dynamo formation in our MHD shell model in the (PrM-1,ReM) plane. The dynamo boundary, which separates dynamo and no-dynamo regions, appears to have a fractal character. We obtain a hysteretic behavior of the order parameter across this boundary and suggestions of nucleation-type phenomena.

  14. What Lessons Should We Learn From Valve’s Innovative Management Model?

    Directory of Open Access Journals (Sweden)

    Julian Birkinshaw

    2015-06-01

    Full Text Available Valve is a fascinating example of a company experimenting with a new way of working – one in which there are no traditional managers, and where employees are encouraged to take direct responsibility for choosing their own projects and completing them in an efficient and effective way. Of course, Valve is not alone in pushing a “manager free” model. Zappos (owned by Amazon is currently experimenting with a similar model they call “holacracy”, and moving further back in time there are such classic examples as W.L. Gore and Associates’ “lattice structure”, Oticon’s “spaghetti organization”, and Brazilian industrial products company, Semco. Nonetheless, Valve’s experiments are note worthy because they are ambitious, visible, and so far very successful.

  15. Meteor layers in the Martian ionosphere: Observations and Modelling

    Science.gov (United States)

    Peter, Kerstin; Molina Cuberos, Gregorio J.; Witasse, Olivier; Paetzold, Martin

    Observations by the radio science experiments MaRS on Mars Express and VeRa on Venus Express revealed the appearance of additional electron density layers in the Martian and Venu-sian ionosphere below the common secondary layers in some of the ionospheric profiles. This may be an indicator for the signature of meteoric particles in the Martian atmosphere. There are two main sources of meteoric flux into planetary atmospheres: the meteoroid stream com-ponent whose origin is related to comets, and the sporadic meteoroid component which has its source in body collisions i.e. in the Kuiper belt or the asteoroid belt. This paper will present the detection status for the Martian meteor layers in MaRS electron density profiles and the first steps towards modelling this feature. The presented meteor layer model will show the influence of the sporadic meteoric component on the Martian ionosphere. Input param-eters to this model are the ablation profiles of atomic Magnesium and Iron in the Martian atmosphere caused by sporadic meteoric influx, the neutral atmosphere which is taken from the Mars Climate Database and electron density profiles for an undisturbed ionosphere from a simple photochemical model. The meteor layer model includes the effects of molecular and eddy diffusion processes of metallic species and contains chemical reaction schemes for atomic Magnesium and Iron. It calculates the altitude-density-profiles for several metallic species on the basis of Mg and Fe in chemical equilibrium by analytical solution of the reaction equations. A first comparison of model and observed meteoric structures in the Martian ionosphere will be presented.

  16. Does murine spermatogenesis require WNT signalling? A lesson from Gpr177 conditional knockout mouse models.

    Science.gov (United States)

    Chen, Su-Ren; Tang, J-X; Cheng, J-M; Hao, X-X; Wang, Y-Q; Wang, X-X; Liu, Y-X

    2016-06-30

    Wingless-related MMTV integration site (WNT) proteins and several other components of the WNT signalling pathway are expressed in the murine testes. However, mice mutant for WNT signalling effector β-catenin using different Cre drivers have phenotypes that are inconsistent with each other. The complexity and overlapping expression of WNT signalling cascades have prevented researchers from dissecting their function in spermatogenesis. Depletion of the Gpr177 gene (the mouse orthologue of Drosophila Wntless), which is required for the secretion of various WNTs, makes it possible to genetically dissect the overall effect of WNTs in testis development. In this study, the Gpr177 gene was conditionally depleted in germ cells (Gpr177(flox/flox), Mvh-Cre; Gpr177(flox/flox), Stra8-Cre) and Sertoli cells (Gpr177(flox/flox), Amh-Cre). No obvious defects in fertility and spermatogenesis were observed in these three Gpr177 conditional knockout (cKO) mice at 8 weeks. However, late-onset testicular atrophy and fertility decline in two germ cell-specific Gpr177 deletion mice were noted at 8 months. In contrast, we did not observe any abnormalities of spermatogenesis and fertility, even in 8-month-old Gpr177(flox/flox), Amh-Cre mice. Elevation of reactive oxygen species (ROS) was detected in Gpr177 cKO germ cells and Sertoli cells and exhibited an age-dependent manner. However, significant increase in the activity of Caspase 3 was only observed in germ cells from 8-month-old germ cell-specific Gpr177 knockout mice. In conclusion, GPR177 in Sertoli cells had no apparent influence on spermatogenesis, whereas loss of GPR177 in germ cells disrupted spermatogenesis in an age-dependent manner via elevating ROS levels and triggering germ cell apoptosis.

  17. Novel insight into glucagon receptor action: lessons from knockout and transgenic mouse models

    OpenAIRE

    Vuguin, P. M.; Charron, M. J.

    2011-01-01

    Using knockout and transgenic technology, genetically modified animal models allowed us to understand the role of glucagon signalling in metabolism. Mice with a global deletion of the glucagon receptor gene (Gcgr) were designed using gene targeting. The phenotype of Gcgr−/− mouse provided important clues about the role of Gcgr in foetal growth, pancreatic development and glucose and lipid homeostasis. The lack of Gcgr activation was associated with: (i) hypoglycaemic pregnancies, poor foetal ...

  18. From Exact to Partial Dynamical Symmetries: Lessons From the Interacting Boson Model

    CERN Document Server

    Leviatan, A

    2012-01-01

    We exploit the rich algebraic structure of the interacting boson model to explain the notion of partial dynamical symmetry (PDS), and present a procedure for constructing Hamiltonians with this property. We demonstrate the relevance of PDS to various topics in nuclear spectroscopy, including K-band splitting, odd-even staggering in the gamma-band and anharmonicity of excited vibrational bands. Special emphasis in this construction is paid to the role of higher-order terms.

  19. MicroRNAs are potential therapeutic targets in fibrosing kidney disease: lessons from animal models

    OpenAIRE

    Duffield, Jeremy S; Grafals, Monica; Portilla, Didier

    2012-01-01

    Chronic disease of the kidneys has reached epidemic proportions in industrialized nations. New therapies are urgently sought. Using a combination of animal models of kidney disease and human biopsy samples, a pattern of dysregulated microRNA expression has emerged which is common to chronic diseases. A number of these dysregulated microRNA have recently been shown to have functional consequences for the disease process and therefore may be potential therapeutic targets. We highlight microRNA-...

  20. Stimulant and motivational effects of alcohol: lessons from rodent and primate models.

    Science.gov (United States)

    Brabant, Christian; Guarnieri, Douglas J; Quertemont, Etienne

    2014-07-01

    In several animal species including humans, the acute administration of low doses of alcohol increases motor activity. Different theories have postulated that alcohol-induced hyperactivity is causally related to alcoholism. Moreover, a common biological mechanism in the mesolimbic dopamine system has been proposed to mediate the stimulant and motivational effects of alcohol. Numerous studies have examined whether alcohol-induced hyperactivity is related to alcoholism using a great variety of animal models and several animal species. However, there is no review that has summarized this extensive literature. In this article, we present the various experimental models that have been used to study the relationship between the stimulant and motivational effects of alcohol in rodents and primates. Furthermore, we discuss whether the theories hypothesizing a causal link between alcohol-induced hyperactivity and alcoholism are supported by published results. The reviewed findings indicate that animal species that are stimulated by alcohol also exhibit alcohol preference. Additionally, the role of dopamine in alcohol-induced hyperactivity is well established since blocking dopaminergic activity suppresses the stimulant effects of alcohol. However, dopamine transmission plays a much more complex function in the motivational properties of alcohol and the neuronal mechanisms involved in alcohol stimulation and reward are distinct. Overall, the current review provides mixed support for theories suggesting that the stimulant effects of alcohol are related to alcoholism and highlights the importance of animal models as a way to gain insight into alcoholism. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Current challenges using models to forecast seawater intrusion: lessons from the Eastern Shore of Virginia, USA

    Science.gov (United States)

    Sanford, Ward E.; Pope, Jason P.

    2010-01-01

    A three-dimensional model of the aquifer system of the Eastern Shore of Virginia, USA was calibrated to reproduce historical water levels and forecast the potential for saltwater intrusion. Future scenarios were simulated with two pumping schemes to predict potential areas of saltwater intrusion. Simulations suggest that only a few wells would be threatened with detectable salinity increases before 2050. The objective was to examine whether salinity increases can be accurately forecast for individual wells with such a model, and to address what the challenges are in making such model forecasts given current (2009) simulation capabilities. The analysis suggests that even with current computer capabilities, accurate simulations of concentrations within a regional-scale (many km) transition zone are computationally prohibitive. The relative paucity of data that is typical for such regions relative to what is needed for accurate transport simulations suggests that even with an infinitely powerful computer, accurate forecasting for a single well would still be elusive. Useful approaches may include local-grid refinement near wells and geophysical surveys, but it is important to keep expectations for simulated forecasts at wells in line with chloride concentration and other data that can be obtained at that local scale.

  2. Lessons learned using different mouse models during space radiation-induced lung tumorigenesis experiments

    Science.gov (United States)

    Wang, Jian; Zhang, Xiangming; Wang, Ping; Wang, Xiang; Farris, Alton B.; Wang, Ya

    2016-06-01

    Unlike terrestrial ionizing radiation, space radiation, especially galactic cosmic rays (GCR), contains high energy charged (HZE) particles with high linear energy transfer (LET). Due to a lack of epidemiologic data for high-LET radiation exposure, it is highly uncertain how high the carcinogenesis risk is for astronauts following exposure to space radiation during space missions. Therefore, using mouse models is necessary to evaluate the risk of space radiation-induced tumorigenesis; however, which mouse model is better for these studies remains uncertain. Since lung tumorigenesis is the leading cause of cancer death among both men and women, and low-LET radiation exposure increases human lung carcinogenesis, evaluating space radiation-induced lung tumorigenesis is critical to enable safe Mars missions. Here, by comparing lung tumorigenesis obtained from different mouse strains, as well as miR-21 in lung tissue/tumors and serum, we believe that wild type mice with a low spontaneous tumorigenesis background are ideal for evaluating the risk of space radiation-induced lung tumorigenesis, and circulating miR-21 from such mice model might be used as a biomarker for predicting the risk.

  3. Modifiers and mechanisms of multi-system polyglutamine neurodegenerative disorders: lessons from fly models

    Indian Academy of Sciences (India)

    Moushami Mallik; Subhash C. Lokhotia

    2010-12-01

    Polyglutamine (polyQ) diseases, resulting from a dynamic expansion of glutamine repeats in a polypeptide, are a class of genetically inherited late onset neurodegenerative disorders which, despite expression of the mutated gene widely in brain and other tissues, affect defined subpopulations of neurons in a disease-specific manner. We briefly review the different poly Q-expansion-induced neurodegenerative disorders and the advantages of modelling them in Drosophila. Studies using the fly models have successfully identified a variety of genetic modifiers and have helped in understanding some of the molecular events that follow expression of the abnormal polyQ proteins. Expression of the mutant polyQ proteins causes, as a consequence of intra-cellular and inter-cellular networking, mis-regulation at multiple steps like transcriptional and post-transcriptional regulations, cell signalling, protein quality control systems (protein folding and degradation networks), axonal transport machinery etc., in the sensitive neurons, resulting ultimately in their death. The diversity of genetic modifiers of polyQ toxicity identified through extensive genetic screens in fly and other models clearly reflects a complex network effect of the presence of the mutated protein. Such network effects pose a major challenge for therapeutic applications.

  4. The genetic architecture of heterochronsy as a quantitative trait: lessons from a computational model.

    Science.gov (United States)

    Sun, Lidan; Sang, Mengmeng; Zheng, Chenfei; Wang, Dongyang; Shi, Hexin; Liu, Kaiyue; Guo, Yanfang; Cheng, Tangren; Zhang, Qixiang; Wu, Rongling

    2017-05-30

    Heterochrony is known as a developmental change in the timing or rate of ontogenetic events across phylogenetic lineages. It is a key concept synthesizing development into ecology and evolution to explore the mechanisms of how developmental processes impact on phenotypic novelties. A number of molecular experiments using contrasting organisms in developmental timing have identified specific genes involved in heterochronic variation. Beyond these classic approaches that can only identify single genes or pathways, quantitative models derived from current next-generation sequencing data serve as a more powerful tool to precisely capture heterochronic variation and systematically map a complete set of genes that contribute to heterochronic processes. In this opinion note, we discuss a computational framework of genetic mapping that can characterize heterochronic quantitative trait loci that determine the pattern and process of development. We propose a unifying model that charts the genetic architecture of heterochrony that perceives and responds to environmental perturbations and evolves over geologic time. The new model may potentially enhance our understanding of the adaptive value of heterochrony and its evolutionary origins, providing a useful context for designing new organisms that can best use future resources. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. Clinical group supervision in yoga therapy: model effects, and lessons learned.

    Science.gov (United States)

    Forbes, Bo; Volpe Horii, Cassandra; Earls, Bethany; Mashek, Stephanie; Akhtar, Fiona

    2012-01-01

    Clinical supervision is an integral component of therapist training and professional development because of its capacity for fostering knowledge, self-awareness, and clinical acumen. Individual supervision is part of many yoga therapy training programs and is referenced in the IAYT Standards as "mentoring." Group supervision is not typically used in the training of yoga therapists. We propose that group supervision effectively supports the growth and development of yoga therapists-in-training. We present a model of group supervision for yoga therapist trainees developed by the New England School of Integrative Yoga Therapeutics™ (The NESIYT Model) that includes the background, structure, format, and development of our inaugural 18-month supervision group. Pre-and post-supervision surveys and analyzed case notes, which captured key didactic and process themes, are discussed. Clinical issues, such as boundaries, performance anxiety, sense of self efficacy, the therapeutic alliance, transference and counter transference, pacing of yoga therapy sessions, evaluation of client progress, and adjunct therapist interaction are reviewed. The timing and sequence of didactic and process themes and benefits for yoga therapist trainees' professional development, are discussed. The NESIYT group supervision model is offered as an effective blueprint for yoga therapy training programs.

  6. Lessons from a Mouse Model Characterizing Features of Vascular Cognitive Impairment with White Matter Changes

    Directory of Open Access Journals (Sweden)

    Masafumi Ihara

    2011-01-01

    Full Text Available With the demographic shift in age in advanced countries inexorably set to progress in the 21st century, dementia will become one of the most important health problems worldwide. Vascular cognitive impairment is the second most common type of dementia after Alzheimer's disease and is frequently responsible for the cognitive decline of the elderly. It is characterized by cerebrovascular white matter changes; thus, in order to investigate the underlying mechanisms involved in white matter changes, a mouse model of chronic cerebral hypoperfusion has been developed, which involves the narrowing of the bilateral common carotid arteries with newly designed microcoils. The purpose of this paper is to provide a comprehensive summary of the achievements made with the model that shows good reproducibility of the white matter changes characterized by blood-brain barrier disruption, glial activation, oxidative stress, and oligodendrocyte loss following chronic cerebral hypoperfusion. Detailed characterization of this model may help to decipher the substrates associated with impaired memory and move toward a more integrated therapy of vascular cognitive impairment.

  7. Lessons in IBD Pathogenesis from New Animal Models of Spontaneous Colitis

    Directory of Open Access Journals (Sweden)

    R Balfour Sartor

    1995-01-01

    Full Text Available The recent explosion of transgenic and targeted gene deleted (knockout [KO] rodents has yielded a number of new animal models of spontaneous, chronic intestinal inflammation that have provided novel insights into the pathogenesis of human inflammatory bowel disease (IBD. Spontaneous colitis resulting from deletion of genes encoding key immunoregulatory cytokines (interleukin [IL]-2, IL-10 and transforming growth factor [TGF]-beta and T cell receptors (TCRs demonstrates that an intact mucosal immune response prevents colitis. The TCR KO model incriminates B lymphocytes in spontaneous colonic inflammation – TCR KO with intact B cells causes colitis, but simultaneous deletion of T and B cells does not. This model and induction of colitis in severe combined immunodeficient (SCID mice by constitution with one T cell subset (CD45RHhi, but prevention by addition of the CD45RBlo subset, strongly suggest that T cell subsets down-regulate inflammation in the normal, immunocompetent host. An essential role for normal luminal bacteria in induction and perpetuation of enterocolitis is provided by the absence of chronic intestinal inflammation in germ-free (sterile IL-2 KO mice and human leukocyte antigen (HLA-B27 transgenic rats, and attenuated inflammation in IL-2 and IL-10 KO mice raised under specific pathogen-free conditions. The fundamental role of host genetic susceptibility in chronic intestinal inflammation and systemic manifestations is established by development of spontaneous colitis and perianal inflammation in C3H/HeJ Bir substrain mice and HLA-B27 transgenic rats.

  8. Lessons learned using different mouse models during space radiation-induced lung tumorigenesis experiments.

    Science.gov (United States)

    Wang, Jian; Zhang, Xiangming; Wang, Ping; Wang, Xiang; Farris, Alton B; Wang, Ya

    2016-06-01

    Unlike terrestrial ionizing radiation, space radiation, especially galactic cosmic rays (GCR), contains high energy charged (HZE) particles with high linear energy transfer (LET). Due to a lack of epidemiologic data for high-LET radiation exposure, it is highly uncertain how high the carcinogenesis risk is for astronauts following exposure to space radiation during space missions. Therefore, using mouse models is necessary to evaluate the risk of space radiation-induced tumorigenesis; however, which mouse model is better for these studies remains uncertain. Since lung tumorigenesis is the leading cause of cancer death among both men and women, and low-LET radiation exposure increases human lung carcinogenesis, evaluating space radiation-induced lung tumorigenesis is critical to enable safe Mars missions. Here, by comparing lung tumorigenesis obtained from different mouse strains, as well as miR-21 in lung tissue/tumors and serum, we believe that wild type mice with a low spontaneous tumorigenesis background are ideal for evaluating the risk of space radiation-induced lung tumorigenesis, and circulating miR-21 from such mice model might be used as a biomarker for predicting the risk.

  9. Modeling a Miniaturized Scanning Electron Microscope Focusing Column - Lessons Learned in Electron Optics Simulation

    Science.gov (United States)

    Loyd, Jody; Gregory, Don; Gaskin, Jessica

    2016-01-01

    This presentation discusses work done to assess the design of a focusing column in a miniaturized Scanning Electron Microscope (SEM) developed at the NASA Marshall Space Flight Center (MSFC) for use in-situ on the Moon-in particular for mineralogical analysis. The MSFC beam column design uses purely electrostatic fields for focusing, because of the severe constraints on mass and electrical power consumption imposed by the goals of lunar exploration and of spaceflight in general. The resolution of an SEM ultimately depends on the size of the focused spot of the scanning beam probe, for which the stated goal here is a diameter of 10 nanometers. Optical aberrations are the main challenge to this performance goal, because they blur the ideal geometrical optical image of the electron source, effectively widening the ideal spot size of the beam probe. In the present work the optical aberrations of the mini SEM focusing column were assessed using direct tracing of non-paraxial rays, as opposed to mathematical estimates of aberrations based on paraxial ray-traces. The geometrical ray-tracing employed here is completely analogous to ray-tracing as conventionally understood in the realm of photon optics, with the major difference being that in electron optics the lens is simply a smoothly varying electric field in vacuum, formed by precisely machined electrodes. Ray-tracing in this context, therefore, relies upon a model of the electrostatic field inside the focusing column to provide the mathematical description of the "lens" being traced. This work relied fundamentally on the boundary element method (BEM) for this electric field model. In carrying out this research the authors discovered that higher accuracy in the field model was essential if aberrations were to be reliably assessed using direct ray-tracing. This led to some work in testing alternative techniques for modeling the electrostatic field. Ultimately, the necessary accuracy was attained using a BEM

  10. Dawn-dusk asymmetries in rotating magnetospheres: Lessons from modeling Saturn

    Science.gov (United States)

    Jia, Xianzhe; Kivelson, Margaret G.

    2016-02-01

    Spacecraft measurements reveal perplexing dawn-dusk asymmetries of field and plasma properties in the magnetospheres of Saturn and Jupiter. Here we describe a previously unrecognized source of dawn-dusk asymmetry in a rapidly rotating magnetosphere. We analyze two magnetohydrodynamic simulations, focusing on how flows along and across the field vary with local time in Saturn's dayside magnetosphere. As plasma rotates from dawn to noon on a dipolarizing flux tube, it flows away from the equator along the flux tube at roughly half of the sound speed (Cs), the maximum speed at which a bulk plasma can flow along a flux tube into a lower pressure region. As plasma rotates from noon to dusk on a stretching flux tube, the field-aligned component of its centripetal acceleration decreases and it flows back toward the equator at speeds typically smaller than 1/2 Cs. Correspondingly, the plasma sheet remains far thicker and the field less stretched in the afternoon than in the morning. Different radial force balance in the morning and afternoon sectors produce asymmetry in the plasma sheet thickness and a net dusk-to-dawn flow inside of L = 15 or equivalently, a large-scale electric field (E) oriented from postnoon to premidnight, as reported from observations. Morning-afternoon asymmetry analogous to that found at Saturn has been observed at Jupiter, and a noon-midnight component of E cannot be ruled out.

  11. The individual teacher in lesson study collaboration

    DEFF Research Database (Denmark)

    Skott, Charlotte Krog; Møller, Hanne

    2017-01-01

    conducted interviews before, between and after two rounds of lesson studies, and recorded the various lesson study activities. Findings This paper provides empirical insights into the complexity of teacher learning. By using the participatory framework, the authors identify significant shifts......Purpose The purpose of this paper is twofold: first, to investigate the learning of individual teachers participating in lesson study collaboration by adapting a participatory framework about teacher learning; and second, to investigate the potential of this framework compared with other approaches...... used in lesson study research. Design/methodology/approach The authors use collective case studies. By being participant observers the authors provide detailed descriptions of two selected teachers’ lived experiences of lesson study collaboration. In addition to gain first-hand insights, the authors...

  12. Study of Observer Variability in Modern Display Colorimetry: Comparison of CIE 2006 Model and 10° Standard Observer

    OpenAIRE

    Sarkar, Abhijit; Blondé, Laurent; Le Callet, Patrick; Autrusseau, Florent; Stauder, Jürgen; Morvan, Patrick

    2009-01-01

    International audience; This paper compares CIE 2006 model predictions and the 1964 10° standard colorimetric observer with the average observer data from three distinct subgroups of 47 Stiles-Burch observers formed on the basis of observer ages. For two of these subgroups, the long-wave sensitive (x-) color matching functions obtained from the CIE06 model did not accurately predict the intra-group average observer functions. In terms of display color perception, the prediction error is refle...

  13. Water security, risk and economic growth: lessons from a dynamical systems model

    Science.gov (United States)

    Dadson, Simon; Hall, Jim; Garrick, Dustin; Sadoff, Claudia; Grey, David; Whittington, Dale

    2016-04-01

    Investments in the physical infrastructure, human capital, and institutions needed for water resources management have been a noteworthy feature in the development of most civilisations. These investments affect the economy in two distinct ways: (i) by improving the factor productivity of water in multiple sectors of the economy, especially those that are water intensive such as agriculture and energy; and (ii) by reducing the acute and chronic harmful effects of water-related hazards like floods, droughts, and water-related diseases. The need for capital investment to mitigate these risks in order to promote economic growth is widely acknowledged, but prior work to conceptualise the relationship between water-related risks and economic growth has focused on the productive and harmful roles of water in the economy independently. Here the two influences are combined using a simple, dynamical model of water-related investment, risk, and growth at the national level. The model suggests the existence of a context-specific threshold above which growth proceeds along an 'S'-curve. In many cases there is a requirement for initial investment in water-related assets to enable growth. Below the threshold it is possible for a poverty trap to arise. The presence and location of the poverty trap is context-specific and depends on the relative exposure of productive water-related assets to risk, compared with risks faced by assets in the wider economy. Exogenous changes in the level of water-related risk (through, for example, climate and land cover change) can potentially push an economy away from a growth path towards a poverty trap. These results illustrate the value of accounting for environmental risk in models of economic growth and may offer guidance in the design of robust policies for investment in water-related productive assets to manage risk, particularly in the face of global and regional environmental change.

  14. Predictive validation of modeled health technology assessment claims: lessons from NICE.

    Science.gov (United States)

    Belsey, Jonathan

    2015-01-01

    The use of cost-effectiveness modeling to prioritize healthcare spending has become a key foundation of UK government policy. Although the preferred method of evaluation-cost-utility analysis-is not without its critics, it represents a standard approach that can arguably be used to assess relative value for money across a range of disease types and interventions. A key limitation of economic modeling, however, is that its conclusions hinge on the input assumptions, many of which are derived from randomized controlled trials or meta-analyses that cannot be reliably linked to real-world performance of treatments in a broader clinical context. This means that spending decisions are frequently based on artificial constructs that may project costs and benefits that are significantly at odds with those that are achievable in reality. There is a clear agenda to carry out some form of predictive validation for the model claims, in order to assess not only whether the spending decisions made can be justified post hoc, but also to ensure that budgetary expenditure continues to be allocated in the most rational way. To date, however, no timely, effective system to carry out this testing has been implemented, with the consequence that there is little objective evidence as to whether the prioritization decisions made are actually living up to expectations. This article reviews two unfulfilled initiatives that have been carried out in the UK over the past 20 years, each of which had the potential to address this objective, and considers why they failed to deliver the expected outcomes.

  15. Barriers of access to care in a managed competition model: lessons from Colombia

    Directory of Open Access Journals (Sweden)

    Mogollón-Pérez Amparo Susana

    2010-10-01

    Full Text Available Abstract Background The health sector reform in Colombia, initiated by Law 100 (1993 that introduced a managed competition model, is generally presented as a successful experience of improving access to care through a health insurance regulated market. The study's objective is to improve our understanding of the factors influencing access to the continuum of care in the Colombian managed competition model, from the social actors' point of view. Methods An exploratory, descriptive-interpretative qualitative study was carried out, based on case studies of four healthcare networks in rural and urban areas. Individual semi-structured interviews were conducted to a three stage theoretical sample: I cases, II providers and III informants: insured and uninsured users (35, health professionals (51, administrative personnel (20, and providers' (18 and insurers' (10 managers. Narrative content analysis was conducted; segmented by cases, informant's groups and themes. Results Access, particularly to secondary care, is perceived as complex due to four groups of obstacles with synergetic effects: segmented insurance design with insufficient services covered; insurers' managed care and purchasing mechanisms; providers' networks structural and organizational limitations; and, poor living conditions. Insurers' and providers' values based on economic profit permeate all factors. Variations became apparent between the two geographical areas and insurance schemes. In the urban areas barriers related to market functioning predominate, whereas in the rural areas structural deficiencies in health services are linked to insufficient public funding. While financial obstacles are dominant in the subsidized regime, in the contributory scheme supply shortage prevails, related to insufficient private investment. Conclusions The results show how in the Colombian healthcare system structural and organizational barriers to care access, that are common in developing countries

  16. Toward analytic theory of the Rayleigh-Taylor instability: lessons from a toy model

    CERN Document Server

    Mailybaev, Alexei A

    2016-01-01

    In this work we suggest that a turbulent phase of the Rayleigh-Taylor instability can be explained as a universal stochastic wave traveling with constant speed in a properly renormalized system. This wave, originating from ordinary deterministic chaos in a renormalized time, has two constant limiting states at both sides. These states are related to the initial discontinuity at large scales and to stationary turbulence at small scales. The theoretical analysis is confirmed with extensive numerical simulations made for a new shell model, which features all basic properties of the phenomenological theory for the Rayleigh-Taylor instability.

  17. Utilizing a logic model to identify clinical research problems: a lesson from philosophy of science

    Directory of Open Access Journals (Sweden)

    Collins CR

    2016-10-01

    Full Text Available Cynthia R Collins School of Nursing, College of Social Sciences, Loyola University, New Orleans, LA, USA Abstract: Communication and decision making in the health care workplace often involve finding solutions to ill-structured problems in uncertain, dynamic environments influenced by the competing interests of multiple stakeholders. In this environment, doctoral-prepared nurses who practice as administrators, policy makers, or advanced practice practitioners are often compelled to make important decisions based upon evaluating the merit of colleagues’ proposals against some desired organizational or population outcome. Of equal importance is the nurse leader’s own capacity to construct a compelling argument or proposal that will drive the organization forward to meet the evolving needs for quality health care. Where do we learn the skills necessary to foster this kind of critical thinking in our professional communications? The author suggests that one teaching–learning approach can be found through the thoughtful application of the work of British philosopher Steven Toulmin. Toulmin defined a model for both the analysis and derivation of logical arguments or proposals that can be readily learned and applied for use in health care systems. This model posits that a substantive argument or claim can be evaluated based on the assumptions it presumes (warrants and the strength of the evidence base (backing. Several of the social science professions have adapted Toulmin’s model to generate analysis and creative solutions to complex or emergent problems. The author proposes that an application of this model be included in the pedagogy of doctoral level Philosophy of Science or Nursing Theory courses. The Toulmin process often provides the doctoral student or novice researcher with their first real learning experience in defining the scope and inherent challenges of framing a clinical issue to be the focus of their scholarly translational

  18. Dust properties inside molecular clouds from coreshine modeling and observations

    CERN Document Server

    Lefèvre, Charlène; Juvela, Mika; Paladini, Roberta; Lallement, Rosine; Marshall, D J; Andersen, Morten; Bacmann, Aurore; Mcgee, Peregrine M; Montier, Ludovic; Noriega-Crespo, Alberto; Pelkonen, V -M; Ristorcelli, Isabelle; Steinacker, Jürgen

    2014-01-01

    Context. Using observations to deduce dust properties, grain size distribution, and physical conditions in molecular clouds is a highly degenerate problem. Aims. The coreshine phenomenon, a scattering process at 3.6 and 4.5 $\\mu$m that dominates absorption, has revealed its ability to explore the densest parts of clouds. We want to use this effect to constrain the dust parameters. The goal is to investigate to what extent grain growth (at constant dust mass) inside molecular clouds is able to explain the coreshine observations. We aim to find dust models that can explain a sample of Spitzer coreshine data. We also look at the consistency with near-infrared data we obtained for a few clouds. Methods. We selected four regions with a very high occurrence of coreshine cases: Taurus-Perseus, Cepheus, Chameleon and L183/L134. We built a grid of dust models and investigated the key parameters to reproduce the general trend of surface bright- nesses and intensity ratios of both coreshine and near-infrared observation...

  19. Coronal loops above an Active Region - observation versus model

    CERN Document Server

    Bourdin, Philippe-A; Peter, Hardi

    2014-01-01

    We conducted a high-resolution numerical simulation of the solar corona above a stable active region. The aim is to test the field-line braiding mechanism for a sufficient coronal energy input. We also check the applicability of scaling laws for coronal loop properties like the temperature and density. Our 3D-MHD model is driven from below by Hinode observations of the photosphere, in particular a high-cadence time series of line-of-sight magnetograms and horizontal velocities derived from the magnetograms. This driving applies stress to the magnetic field and thereby delivers magnetic energy into the corona, where currents are induced that heat the coronal plasma by Ohmic dissipation. We compute synthetic coronal emission that we directly compare to coronal observations of the same active region taken by Hinode. In the model, coronal loops form at the same places as they are found in coronal observations. Even the shapes of the synthetic loops in 3D space match those found from a stereoscopic reconstruction ...

  20. Immune Memory and Exhaustion: Clinically Relevant Lessons from the LCMV Model.

    Science.gov (United States)

    Zehn, D; Wherry, E J

    2015-01-01

    The development of dysfunctional or exhausted T cells is characteristic of immune responses to chronic viral infections and cancer. Exhausted T cells are defined by reduced effector function, sustained upregulation of multiple inhibitory receptors, an altered transcriptional program and perturbations of normal memory development and homeostasis. This review focuses on (a) illustrating milestone discoveries that led to our present understanding of T cell exhaustion, (b) summarizing recent developments in the field, and (c) identifying new challenges for translational research. Exhausted T cells are now recognized as key therapeutic targets in human infections and cancer. Much of our knowledge of the clinically relevant process of exhaustion derives from studies in the mouse model of Lymphocytic choriomeningitis virus (LCMV) infection. Studies using this model have formed the foundation for our understanding of human T cell memory and exhaustion. We will use this example to discuss recent advances in our understanding of T cell exhaustion and illustrate the value of integrated mouse and human studies and will emphasize the benefits of bi-directional mouse-to-human and human-to-mouse research approaches.

  1. Integrated complex care model: lessons learned from inter-organizational partnership.

    Science.gov (United States)

    Cohen, Eyal; Bruce-Barrett, Cindy; Kingsnorth, Shauna; Keilty, Krista; Cooper, Anna; Daub, Stacey

    2011-01-01

    Providing integrated care for children with medical complexity in Canada is challenging as these children are, by definition, in need of coordinated care from disparate providers, organizations and funders across the continuum in order to optimize health outcomes. We describe the development of an inter-organizational team constructed as a unique tripartite partnership of an acute care hospital, a children's rehabilitation hospital and a home/community health organization focused on children who frequently use services across these three organizations. Model building and operationalization within the Canadian healthcare system is emphasized. Key challenges identified to date include communication and policy barriers as well as optimizing interactions with families; critical enablers have been alignment with policy trends in healthcare and inter-organizational commitment to integrate at the point of care. Considerations for policy developments supporting full integration across service sectors are raised. Early indicators of success include the enrolment of 34 clients and patients and the securing of funds to evaluate and expand the model to serve more children.

  2. Non-invasive evaluation of placental blood flow: lessons from animal models.

    Science.gov (United States)

    Mourier, E; Tarrade, A; Duan, J; Richard, C; Bertholdt, C; Beaumont, M; Morel, O; Chavatte-Palmer, P

    2017-03-01

    In human obstetrics, placental vascularisation impairment is frequent as well as linked to severe pathological events (preeclampsia and intrauterine growth restriction), and there is a need for reliable methods allowing non-invasive evaluation of placental blood flow. Uteroplacental vascularisation is complex, and animal models are essential for the technical development and safety assessment of these imaging tools for human clinical use; however, these techniques can also be applied in the veterinary context. This paper reviews how ultrasound-based imaging methods such as 2D and 3D Doppler can provide valuable insight for the exploration of placental blood flow both in humans and animals and how new approaches such as the use of ultrasound contrast agents or ultrafast Doppler may allow to discriminate between maternal (non-pulsatile) and foetal (pulsatile) blood flow in the placenta. Finally, functional magnetic resonance imaging could also be used to evaluate placental blood flow, as indicated by studies in animal models, but its safety in human pregnancy still requires to be confirmed. © 2017 Society for Reproduction and Fertility.

  3. Land Surface Microwave Emissivity Dynamics: Observations, Analysis and Modeling

    Science.gov (United States)

    Tian, Yudong; Peters-Lidard, Christa D.; Harrison, Kenneth W.; Kumar, Sujay; Ringerud, Sarah

    2014-01-01

    Land surface microwave emissivity affects remote sensing of both the atmosphere and the land surface. The dynamical behavior of microwave emissivity over a very diverse sample of land surface types is studied. With seven years of satellite measurements from AMSR-E, we identified various dynamical regimes of the land surface emission. In addition, we used two radiative transfer models (RTMs), the Community Radiative Transfer Model (CRTM) and the Community Microwave Emission Modeling Platform (CMEM), to simulate land surface emissivity dynamics. With both CRTM and CMEM coupled to NASA's Land Information System, global-scale land surface microwave emissivities were simulated for five years, and evaluated against AMSR-E observations. It is found that both models have successes and failures over various types of land surfaces. Among them, the desert shows the most consistent underestimates (by approx. 70-80%), due to limitations of the physical models used, and requires a revision in both systems. Other snow-free surface types exhibit various degrees of success and it is expected that parameter tuning can improve their performances.

  4. Atmospheric Circulation on Hot Jupiters: Modeling and Observable Signatures

    Science.gov (United States)

    Rauscher, Emily Christine

    2010-12-01

    Hot Jupiters are unlike any planets in our Solar System and yet one of the most common types of extrasolar planet discovered. These gas giants orbit their parent stars with periods of a few days. Expected to be tidally locked into synchronous rotation, hot Jupiters experience intense, asymmetric heating from stellar irradiation, such that day-night temperature contrasts could reach hundreds of degrees Kelvin. This unique state of radiative forcing, as well as the slow rotation rates of these planets, places hot Jupiters within a new regime of atmospheric circulation. Hot Jupiters have also been the first type of extrasolar planet with direct detections of their atmospheres, through measurements of emitted, reflected, and transmitted light. This thesis investigates observational methods to distinguish between various atmospheric models, observational signatures of potential atmospheric variability, and presents a three dimensional model with which to study hot Jupiter circulation patterns. First, we find that eclipse mapping is a technique that can be used to image the day sides of these planets and although this is beyond the ability of current instruments, it will be achievable with future missions, such as the James Webb Space Telescope. Second, we consider the signatures of large-scale atmospheric variability in measurements of secondary eclipses and thermal orbital phase curves. For various models we predict the amount of variation in eclipse depth, and the amplitudes and detailed shapes of phase curves. Lastly, we develop a three-dimensional model of hot Jupiter atmospheric dynamics with simplified forcing and adopt a set-up nearly identical to work by another group to facilitate code inter-comparison. Our results are broadly consistent with theirs, with a transonic flow and the hottest region of the atmosphere advected eastward of the substellar point. However, we note important differences and identify areas of concern for future modeling efforts.

  5. Further ALMA observations and detailed modeling of the Red Rectangle

    CERN Document Server

    Bujarrabal, V; Alcolea, J; Santander-Garcia, M; Van Winckel, H; Contreras, C Sanchez

    2016-01-01

    We present new high-quality ALMA observations of the Red Rectangle (a well known post-AGB object) in C17O J=6-5 and H13CN J=4-3 line emission and results from a new reduction of already published 13CO J=3-2 data. A detailed model fitting of all the molecular line data, including previous maps and single-dish spectra, was performed using a sophisticated code. These observations and the corresponding modeling allowed us to deepen the analysis of the nebular properties. We also stress the uncertainties in the model fitting. We confirm the presence of a rotating equatorial disk and an outflow, which is mainly formed of gas leaving the disk. The mass of the disk is ~ 0.01 Mo, and that of the CO-rich outflow is ~ 10 times smaller. High temperatures of ~ 100 K are derived for most components. From comparison of the mass values, we roughly estimate the lifetime of the rotating disk, which is found to be of about 10000 yr. Taking data of a few other post-AGB composite nebulae into account, we find that the lifetimes o...

  6. Anisotropy in Fracking: A Percolation Model for Observed Microseismicity

    Science.gov (United States)

    Norris, J. Quinn; Turcotte, Donald L.; Rundle, John B.

    2015-01-01

    Hydraulic fracturing (fracking), using high pressures and a low viscosity fluid, allow the extraction of large quantiles of oil and gas from very low permeability shale formations. The initial production of oil and gas at depth leads to high pressures and an extensive distribution of natural fractures which reduce the pressures. With time these fractures heal, sealing the remaining oil and gas in place. High volume fracking opens the healed fractures allowing the oil and gas to flow to horizontal production wells. We model the injection process using invasion percolation. We use a 2D square lattice of bonds to model the sealed natural fractures. The bonds are assigned random strengths and the fluid, injected at a point, opens the weakest bond adjacent to the growing cluster of opened bonds. Our model exhibits burst dynamics in which the clusters extend rapidly into regions with weak bonds. We associate these bursts with the microseismic activity generated by fracking injections. A principal object of this paper is to study the role of anisotropic stress distributions. Bonds in the y-direction are assigned higher random strengths than bonds in the x-direction. We illustrate the spatial distribution of clusters and the spatial distribution of bursts (small earthquakes) for several degrees of anisotropy. The results are compared with observed distributions of microseismicity in a fracking injection. Both our bursts and the observed microseismicity satisfy Gutenberg-Richter frequency-size statistics.

  7. Model and observed seismicity represented in a two dimensional space

    Directory of Open Access Journals (Sweden)

    M. Caputo

    1976-06-01

    Full Text Available In recent years theoretical seismology lias introduced
    some formulae relating the magnitude and the seismic moment of earthquakes
    to the size of the fault and the stress drop which generated the
    earthquake.
    In the present paper we introduce a model for the statistics of the
    earthquakes based on these formulae. The model gives formulae which
    show internal consistency and are also confirmed by observations.
    For intermediate magnitudes the formulae reproduce also the trend
    of linearity of the statistics of magnitude and moment observed in all the
    seismic regions of the world. This linear trend changes into a curve with
    increasing slope for large magnitudes and moment.
    When a catalogue of the magnitudes and/or the seismic moment of
    the earthquakes of a seismic region is available, the model allows to estimate
    the maximum magnitude possible in the region.

  8. Long-term Engagement in Authentic Research with NASA (LEARN): Lessons Learned from an Innovative Model for Teacher Research Experiences

    Science.gov (United States)

    Pippin, M. R.; Kollmeyer, R.; Joseph, J.; Yang, M. M.; Omar, A. H.; Harte, T.; Taylor, J.; Lewis, P. M.; Weisman, A.; Hyater-Adams, S.

    2013-12-01

    teachers have changed their ability to communicate the results of research to the public. During this presentation, we will share the LEARN model, findings from the evaluation, and our lessons learned in providing meaningful scientific research experiences for teachers. Our model incorporates intensive support and mentoring, ongoing virtual and face-to-face check-ins, and flexibility to meet teachers' needs on their research projects and in their classrooms.

  9. Probability distribution analysis of observational extreme events and model evaluation

    Science.gov (United States)

    Yu, Q.; Lau, A. K. H.; Fung, J. C. H.; Tsang, K. T.

    2016-12-01

    Earth's surface temperatures were the warmest in 2015 since modern record-keeping began in 1880, according to the latest study. In contrast, a cold weather occurred in many regions of China in January 2016, and brought the first snowfall to Guangzhou, the capital city of Guangdong province in 67 years. To understand the changes of extreme weather events as well as project its future scenarios, this study use statistical models to analyze on multiple climate data. We first use Granger-causality test to identify the attribution of global mean temperature rise and extreme temperature events with CO2 concentration. The four statistical moments (mean, variance, skewness, kurtosis) of daily maximum temperature distribution is investigated on global climate observational, reanalysis (1961-2010) and model data (1961-2100). Furthermore, we introduce a new tail index based on the four moments, which is a more robust index to measure extreme temperatures. Our results show that the CO2 concentration can provide information to the time series of mean and extreme temperature, but not vice versa. Based on our new tail index, we find that other than mean and variance, skewness is an important indicator should be considered to estimate extreme temperature changes and model evaluation. Among the 12 climate model data we investigate, the fourth version of Community Climate System Model (CCSM4) from National Center for Atmospheric Research performs well on the new index we introduce, which indicate the model have a substantial capability to project the future changes of extreme temperature in the 21st century. The method also shows its ability to measure extreme precipitation/ drought events. In the future we will introduce a new diagram to systematically evaluate the performance of the four statistical moments in climate model output, moreover, the human and economic impacts of extreme weather events will also be conducted.

  10. Developing Sustainable Modeling Software and Necessary Data Repository for Volcanic Hazard Analysis -- Some Lessons Learnt

    Science.gov (United States)

    Patra, A. K.; Connor, C.; Webley, P.; Jones, M.; Charbonnier, S. J.; Connor, L.; Gallo, S.; Bursik, M. I.; Valentine, G.; Hughes, C. G.; Aghakhani, H.; Renschler, C. S.; Kosar, T.

    2014-12-01

    We report here on an effort to improve the sustainability, robustness and usability of the core modeling and simulation tools housed in the collaboratory VHub.org and used in the study of complex volcanic behavior. In particular, we focus on tools that support large scale mass flows (TITAN2D), ash deposition/transport and dispersal (Tephra2 and PUFF), and lava flows (Lava2). These tools have become very popular in the community especially due to the availability of an online usage modality. The redevelopment of the tools ot take advantage of new hardware and software advances was a primary thrust for the effort. However, as we start work we have reoriented the effort to also take advantage of significant new opportunities for supporting the complex workflows and use of distributed data resources that will enable effective and efficient hazard analysis.

  11. Merging symmetry projection methods with coupled cluster theory: Lessons from the Lipkin model Hamiltonian

    CERN Document Server

    Wahlen-Strothman, Jacob M; Hermes, Matthew R; Degroote, Matthias; Qiu, Yiheng; Zhao, Jinmo; Dukelsky, Jorge; Scuseria, Gustavo E

    2016-01-01

    Coupled cluster and symmetry projected Hartree-Fock are two central paradigms in electronic structure theory. However, they are very different. Single reference coupled cluster is highly successful for treating weakly correlated systems, but fails under strong correlation unless one sacrifices good quantum numbers and works with broken-symmetry wave functions, which is unphysical for finite systems. Symmetry projection is effective for the treatment of strong correlation at the mean-field level through multireference non-orthogonal configuration interaction wavefunctions, but unlike coupled cluster, it is neither size extensive nor ideal for treating dynamic correlation. We here examine different scenarios for merging these two dissimilar theories. We carry out this exercise over the integrable Lipkin model Hamiltonian, which despite its simplicity, encompasses non-trivial physics for degenerate systems and can be solved via diagonalization for a very large number of particles. We show how symmetry projection...

  12. How chromosome mis-segregation leads to cancer: lessons from BubR1 mouse models.

    Science.gov (United States)

    Lee, Hyunsook

    2014-10-31

    Alteration in chromosome numbers and structures instigate and foster massive genetic instability. As Boveri has seen a hundred years ago (Boveri, 1914; 2008), aneuploidy is hallmark of many cancers. However, whether aneuploidy is the cause or the result of cancer is still at debate. The molecular mechanism behind aneuploidy includes the chromo-some mis-segregation in mitosis by the compromise of spindle assembly checkpoint (SAC). SAC is an elaborate network of proteins, which monitor that all chromosomes are bipolarly attached with the spindles. Therefore, the weakening of the SAC is the major reason for chromosome number instability, while complete compromise of SAC results in detrimental death, exemplified in natural abortion in embryonic stage. Here, I will review on the recent progress on the understanding of chromosome mis-segregation and cancer, based on the comparison of different mouse models of BubR1, the core component of SAC.

  13. Towards a Reference Model for Open Access and Knowledge Sharing, Lessons from Systems Research

    CERN Document Server

    Di Maio, Paola

    2011-01-01

    The Open Access Movement has been striving to grant universal unrestricted access to the knowledge and data outputs of publicly funded research. leveraging the real time, virtually cost free publishing opportunities offered by the internet and the web. However, evidence suggests that in the systems engineering domain open access policies are not widely adopted. This paper presents the rationale, methodology and results of an evidence based inquiry that investigates the dichotomy between policy and practice in Open Access (OA) of systems engineering research in the UK, explores entangled dimensions of the problem space from a socio-technical perspective, and issues a set of recommendations, including a reference model outline for knowledge sharing in systems research

  14. Poly-generation planning: useful lessons from models and decision support tools

    DEFF Research Database (Denmark)

    Rong, Aiying; Lahdelma, Risto; Grunow, Martin

    2009-01-01

    awareness calls for explicit handling of the impacts of energy generation on environment. Advanced production technologies require more sophisticated models for planning. The energy sector is one of the core application areas for operations research, decision sciences and intelligent techniques......Increasing environmental concerns and the trends towards deregulation of energy markets have become an integral part of energy policy planning. Consequently, the requirement for environmentally sound energy production technologies has gained much ground in the energy business. The development...... of energy-efficient production technologies has experienced cogeneration and tri-generation and now is moving towards poly-generation. All these aspects have added new dimension in energy planning. The liberalized energy market requires techniques for planning under uncertainty. The growing environmental...

  15. Economic model of observation versus immediate resection of hepatic adenomas.

    Science.gov (United States)

    Vanounou, Tsafrir; Groeschl, Ryan T; Geller, David A; Marsh, J Wallis; Gamblin, T Clark

    2012-09-15

    For small asymptomatic hepatic adenomas (HA), available data are insufficient to establish the superiority of either observation or surgery. We sought to investigate the cost-effectiveness of two initial management strategies. We performed a comparative analysis of two theoretical cohorts of 100 patients with small (cash flow (DCF) models compared the net present value (NPV) of both treatment options at year 10 under three distinct progression rate scenarios. A break-even (BE) analysis was used to determine the BE point at which the NPV for observation and immediate surgery intersect. The NPV for immediate surgery was $1,733,955. The NPV for observation varied between $2,065,315-$2,745,631 for computed tomography (CT), $2,264,575-$2,929,541 for magnetic resonance imaging (MRI), and $802,837-$1,580,413 for ultrasound (US). The BE point was between 6 and 8 years for CT and 5-7 years for MRI. The BE point for US was not reached except in the highest progression rate scenario (12 years). This study highlights the importance of the underlying progression rate and the cost of imaging when following patients with asymptomatic HA. Overall, US surveillance is the most cost-efficient approach to observing small asymptomatic HA. If cross-sectional imaging is utilized, then immediate surgery is the most cost-effective decision at 5-8 years. Copyright © 2012 Wiley Periodicals, Inc.

  16. A framework to explore the visual brain in glaucoma with lessons from models and man.

    Science.gov (United States)

    Yucel, Yeni H; Gupta, Neeru

    2015-12-01

    Vision loss in glaucoma is associated with death of retinal ganglion cells. High intraocular pressure is a major risk factor for vision loss from glaucoma, and lowering eye pressure is the goal of all available medical and surgical treatments. Taking a bold step forward, the restoration of vision after severe glaucoma damage is a new Audacious Goal established by National Eye Institute (Sieving, 2012). This means that retinal ganglion cell repair, and replacement, must be considered in the context of visual function restoration. To restore visual function, retinal ganglion cells, after long-distance axonal growth and guidance, should connect to specific target neurons in subcortical visual structures. At the time of the establishment of these connections, the fate of target cells is critical along with the health of retinal ganglion cells. In fact, several lines of evidence demonstrate glaucomatous neural degeneration occurs throughout the central visual system where most information processing takes place. Evidence from multiple studies in experimental glaucoma models, human autopsy cases and neuroimaging studies point to the degeneration of neurons in the lateral geniculate nucleus, a subcortical hub of functional connectivity between the eye and the visual cortex. Maintaining and re-establishing connections of retinal ganglion cells to target neurons in major visual structures is a key endpoint for regenerative medicine strategies. This paper critically reviews studies of visual brain changes in man and experimental animal models, and discusses key factors in the experimental design that are relevant to restoring vision loss in human disease. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Better Communication Through Collaboration: Lessons Learned from a New Model of Science Communication Education

    Science.gov (United States)

    Hayden, T.

    2011-12-01

    Direct, effective communication with the public is an increasingly important part of the earth scientist's professional toolkit. Earth sciences issues, including climate change, ocean acidification, energy extraction and use and geological hazard assessment, are increasingly relevant to public debates, yet recent, dramatic changes in the media business have led to decreased coverage of science. Earth scientists must increasingly shoulder the burden of informing the broad public themselves, and in collaboration with professional communicators. Fortunately, the tools and venues needed to do so have never been more accessible. This presentation will describe a new model of science communication education, based on bringing together collaborating teams of students with diverse backgrounds in the sciences, engineering and journalism. The project-based approach uses group workshopping and multiple rounds of peer- and instructor-guided revision to leverage diverse expertise and facilitate both primary knowledge gain and comprehensive, effective and meaningful training and experience in audience-focused outreach, media interaction, and journalism. Courses build from fundamental communications theory to the end goal of publication in professional outlets. Course goals are regularly enhanced and reinforced with internships and individual study projects. Using examples from a series of courses and projects developed at Stanford University over the past three years, I will describe the theory and strategies underlying this new approach to science communication education, what it has to offer for scientists and journalists alike, and key points to consider for effective implementation. I will also show how combining the knowledge, expertise and experience of STEM and journalism students can inform a new model of science journalism, based on exploring and communicating the process of science, not just the results, that can avoid many of the common pitfalls of science journalism

  18. Implications of RHESSI Flare Observations for Magnetic Reconnection Models

    Science.gov (United States)

    Holman, Gordon D.; Sui, Linhui; Dennis, Brian R.

    2004-01-01

    The Ramaty High Energy Solar Spectroscopic Imager (RHESSI) observations of the 2002 April 15 solar flare and related flares provide compelling evidence for the formation of a large-scale, reconnecting current sheet in at least some flares. We describe the observed evolution of the April 15 flare in terms of magnetic reconnection models. We argue that the flare most likely evolved through magnetic geometries associated with super-slow reconnection (early rise phase), fast reconnection (impulsive phase), and slow reconnection (gradual phase). We also provide evidence for X-ray brightenings within the evolving current sheet, possibly induced by the tearing mode instability. This work was supported in part by the RHESSI Program and NASA's Sun-Earth Connection Program. This work would not have been possible without the dedicated efforts of the entire RHESSI team.

  19. Structures and components in galaxy clusters: observations and models

    CERN Document Server

    Bykov, A M; Ferrari, C; Forman, W R; Kaastra, J S; Klein, U; Markevitch, M; de Plaa, J

    2015-01-01

    Clusters of galaxies are the largest gravitationally bounded structures in the Universe dominated by dark matter. We review the observational appearance and physical models of plasma structures in clusters of galaxies. Bubbles of relativistic plasma which are inflated by supermassive black holes of AGNs, cooling and heating of the gas, large scale plasma shocks, cold fronts, non-thermal halos and relics are observed in clusters. These constituents are reflecting both the formation history and the dynamical properties of clusters of galaxies. We discuss X-ray spectroscopy as a tool to study the metal enrichment in clusters and fine spectroscopy of Fe X-ray lines as a powerful diagnostics of both the turbulent plasma motions and the energetics of the non-thermal electron populations. The knowledge of the complex dynamical and feedback processes is necessary to understand the energy and matter balance as well as to constrain the role of the non-thermal components of clusters.

  20. Modelling 1-minute directional observations of the global irradiance.

    Science.gov (United States)

    Thejll, Peter; Pagh Nielsen, Kristian; Andersen, Elsa; Furbo, Simon

    2016-04-01

    Direct and diffuse irradiances from the sky has been collected at 1-minute intervals for about a year from the experimental station at the Technical University of Denmark for the IEA project "Solar Resource Assessment and Forecasting". These data were gathered by pyrheliometers tracking the Sun, as well as with apertured pyranometers gathering 1/8th and 1/16th of the light from the sky in 45 degree azimuthal ranges pointed around the compass. The data are gathered in order to develop detailed models of the potentially available solar energy and its variations at high temporal resolution in order to gain a more detailed understanding of the solar resource. This is important for a better understanding of the sub-grid scale cloud variation that cannot be resolved with climate and weather models. It is also important for optimizing the operation of active solar energy systems such as photovoltaic plants and thermal solar collector arrays, and for passive solar energy and lighting to buildings. We present regression-based modelling of the observed data, and focus, here, on the statistical properties of the model fits. Using models based on the one hand on what is found in the literature and on physical expectations, and on the other hand on purely statistical models, we find solutions that can explain up to 90% of the variance in global radiation. The models leaning on physical insights include terms for the direct solar radiation, a term for the circum-solar radiation, a diffuse term and a term for the horizon brightening/darkening. The purely statistical model is found using data- and formula-validation approaches picking model expressions from a general catalogue of possible formulae. The method allows nesting of expressions, and the results found are dependent on and heavily constrained by the cross-validation carried out on statistically independent testing and training data-sets. Slightly better fits -- in terms of variance explained -- is found using the purely

  1. Precision Electroweak Observables in the Minimal Moose Little Higgs Model

    CERN Document Server

    Kilic, C; Kilic, Can; Mahbubani, Rakhi

    2004-01-01

    Little Higgs theories, in which the Higgs particle is realized as the pseudo-Goldstone boson of an approximate global chiral symmetry have generated much interest as possible alternatives to weak scale supersymmetry. In this paper we place constraints on the parameters of two such models by comparing their contributions to precision electroweak observables with current experimental bounds. This is done in the effective field theory framework by matching coefficients of operators in the low and high energy theories at around 1 TeV.

  2. On the Ungerboeck and Forney Observation Models for Offset QPSK

    Science.gov (United States)

    2012-03-12

    ANSI Std. Z39.18 On the Ungerboeck and Forney Observation Models for Offset QPSK Michael Rice Brigham Young University Provo, UT 84602 Email: mdr ... Tb is the bit time (sec/bit), and the binary symbols x(n) are defined by x(n) = { a(n) n even ja(n) n odd . (5) Here, OQPSK is thought of as a binary...3] (see also [9]) and an equivalent CPM representation [8, Chapter 3] (see also [10]). 2Because both Tb and Ts = 2Tb spaced pulse trains are

  3. Parental modelling of eating behaviours: observational validation of the Parental Modelling of Eating Behaviours scale (PARM).

    Science.gov (United States)

    Palfreyman, Zoe; Haycraft, Emma; Meyer, Caroline

    2015-03-01

    Parents are important role models for their children's eating behaviours. This study aimed to further validate the recently developed Parental Modelling of Eating Behaviours Scale (PARM) by examining the relationships between maternal self-reports on the PARM with the modelling practices exhibited by these mothers during three family mealtime observations. Relationships between observed maternal modelling and maternal reports of children's eating behaviours were also explored. Seventeen mothers with children aged between 2 and 6 years were video recorded at home on three separate occasions whilst eating a meal with their child. Mothers also completed the PARM, the Children's Eating Behaviour Questionnaire and provided demographic information about themselves and their child. Findings provided validation for all three PARM subscales, which were positively associated with their observed counterparts on the observational coding scheme (PARM-O). The results also indicate that habituation to observations did not change the feeding behaviours displayed by mothers. In addition, observed maternal modelling was significantly related to children's food responsiveness (i.e., their interest in and desire for foods), enjoyment of food, and food fussiness. This study makes three important contributions to the literature. It provides construct validation for the PARM measure and provides further observational support for maternal modelling being related to lower levels of food fussiness and higher levels of food enjoyment in their children. These findings also suggest that maternal feeding behaviours remain consistent across repeated observations of family mealtimes, providing validation for previous research which has used single observations. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Observable Algebra in Field Algebra of G-spin Models

    Institute of Scientific and Technical Information of China (English)

    蒋立宁

    2003-01-01

    Field algebra of G-spin models can provide the simplest examples of lattice field theory exhibiting quantum symmetry. Let D(G) be the double algebra of a finite group G and D(H), a sub-algebra of D(G) determined by subgroup H of G. This paper gives concrete generators and the structure of the observable algebra AH, which is a D(H)-invariant sub-algebra in the field algebra of G-spin models F, and shows that AH is a C*-algebra. The correspondence between H and AH is strictly monotonic. Finally, a duality between D(H) and AH is given via an irreducible vacuum C*-representation of F.

  5. Analysis of rainfall seasonality from observations and climate models

    CERN Document Server

    Pascale, Salvatore; Feng, Xue; Porporato, Amilcare; Hasson, Shabeh-ul

    2014-01-01

    Precipitation seasonality of observational datasets and CMIP5 historical simulations are analyzed using novel quantitative measures based on information theory. Two new indicators, the relative entropy (RE) and the dimensionless seasonality index (DSI), together with the mean annual rainfall, are evaluated on a global scale for recently updated precipitation gridded datasets and for historical simulations from coupled atmosphere-ocean general circulation models. The RE provides a measure of how peaked the shape of the annual rainfall curve is whereas the DSI quantifies the intensity of the rainfall during the wet season. The global monsoon regions feature the largest values of the DSI. For precipitation regimes featuring one maximum in the monthly rain distribution the RE is related to the duration of the wet season. We show that the RE and the DSI are measures of rainfall seasonality fairly independent of the time resolution of the precipitation data, thereby allowing objective metrics for model intercompari...

  6. Dispersion Relations for Electroweak Observables in Composite Higgs Models

    CERN Document Server

    Contino, Roberto

    2015-01-01

    We derive dispersion relations for the electroweak oblique observables measured at LEP in the context of $SO(5)/SO(4)$ composite Higgs models. It is shown how these relations can be used and must be modified when modeling the spectral functions through a low-energy effective description of the strong dynamics. The dispersion relation for the parameter $\\epsilon_3$ is then used to estimate the contribution from spin-1 resonances at the 1-loop level. Finally, it is shown that the sign of the contribution to the $\\hat S$ parameter from the lowest-lying spin-1 states is not necessarily positive definite, but depends on the energy scale at which the asymptotic behavior of current correlators is attained.

  7. Models for Near-Ridge Seamounts Constrained by Gravity Observations

    Science.gov (United States)

    Kostlan, M.; McClain, J. S.

    2009-12-01

    In an analysis of the seamount chain centered at 105°20’W, 9°05’N, west of the East Pacific Rise and south of the Clipperton transform fault, we compared measured free air gravity anomaly values with modeled gravity anomaly values. The seamount chain contains approximately ten seamounts trending roughly east-west, perpendicular to the mid-ocean ridge axis. They lie on lithosphere between 1.5 and 2.7 Ma in age. Based on its position and age, the seamount chain appears to be associated with the 9°03’N overlapping spreading center (OSC). This OSC includes several associated seamount chains, aligned generally east-west, and of varying ages. The observed data include both free air gravity anomalies and bathymetry of the seamount chain, provided by the National Geophysical Data Center (NGDC), and was selected because the gravity measurements are relatively well covered. We used a series of different structural models of the oceanic crust and mantle to generate gravity anomalies associated with the sea mounts. The models utilize Parker’s algorithm to generate these free air gravity anomalies. We compute a gravity residual by subtracting the calculated anomalies from the observed anomalies. The models include one with a crust of a constant thickness (6 km), while another introduces a constant-thickness Layer 2A. In contrast, a third model included a variable thickness crust, where the thickness is governed by Airy compensation. The calculations show that the seamounts must be partly compensated, because the constant-thickness models predict a high negative residual (or they produce an anomaly which is too high). In contrast, the Airy compensation model produces an anomaly that is too low at the longer wavelengths, indicating that the lithosphere must have some strength, and that flexure must be supporting part of the load of the seamount chain. This contrasts with earlier studies that indicate young, near-ridge seamounts do not result in flexure of the thin

  8. Mechanisms and functional implications of social buffering in infants: Lessons from animal models.

    Science.gov (United States)

    Sullivan, Regina M; Perry, Rosemarie E

    2015-01-01

    Social buffering, which is the attenuation of stress hormone release by a social partner, occurs in many species throughout the lifespan. Social buffering of the infant by the caregiver is particularly robust, and animal models using infant rodents are uncovering the mechanisms and neural circuitry supporting social buffering. At birth, the hypothalamic-pituitary-adrenal (HPA) stress system is functional but is suppressed via extended social buffering by the mother: the profound social buffering effects of the mother can last for 1-2 hours when pups are removed from the mother. At 10 days of age, pups begin to mount a stress response immediately when separated from the mother. The stimuli from the mother supporting social buffering are broad, for tactile stimulation, milk, and an anesthetized mother (no maternal behavior) all sufficiently support social buffering. The mother appears to produce social buffering by blocking norepinephrine (NE) release into the hypothalamic paraventricular nucleus (PVN), which blocks HPA activation. Since the infant amygdala relies on the presence of corticosterone (CORT), this suggests that social buffering of pups by the mother attenuates the neurobehavioral stress response in infancy and prevents pups from learning about threat within mother-infant interactions.

  9. Challenges in Mucosal HIV Vaccine Development: Lessons from Non-Human Primate Models

    Directory of Open Access Journals (Sweden)

    Iskra Tuero

    2014-08-01

    Full Text Available An efficacious HIV vaccine is urgently needed to curb the AIDS pandemic. The modest protection elicited in the phase III clinical vaccine trial in Thailand provided hope that this goal might be achieved. However, new approaches are necessary for further advances. As HIV is transmitted primarily across mucosal surfaces, development of immunity at these sites is critical, but few clinical vaccine trials have targeted these sites or assessed vaccine-elicited mucosal immune responses. Pre-clinical studies in non-human primate models have facilitated progress in mucosal vaccine development by evaluating candidate vaccine approaches, developing methodologies for collecting and assessing mucosal samples, and providing clues to immune correlates of protective immunity for further investigation. In this review we have focused on non-human primate studies which have provided important information for future design of vaccine strategies, targeting of mucosal inductive sites, and assessment of mucosal immunity. Knowledge gained in these studies will inform mucosal vaccine design and evaluation in human clinical trials.

  10. The epigenetics of germ-line immortality: lessons from an elegant model system.

    Science.gov (United States)

    Furuhashi, Hirofumi; Kelly, William G

    2010-08-01

    Epigenetic mechanisms are thought to help regulate the unique transcription program that is established in germ cell development. During the germline cycle of many organisms, the epigenome undergoes waves of extensive resetting events, while a part of epigenetic modification remains faithful to specific loci. Little is known about the mechanisms underlying these events, how loci are selected for, or avoid, reprogramming, or even why these events are required. In particular, although the significance of genomic imprinting phenomena involving DNA methylation in mammals is now well accepted, the role of histone modification as a transgenerational epigenetic mechanism has been the subject of debate. Such epigenetic mechanisms may help regulate transcription programs and/or the pluripotent status conferred on germ cells, and contribute to germ line continuity across generations. Recent studies provide new evidence for heritability of histone modifications through germ line cells and its potential effects on transcription regulation both in the soma and germ line of subsequent generations. Unraveling transgenerational epigenetic mechanisms involving highly conserved histone modifications in elegant model systems will accelerate the generation of new paradigms and inspire research in a wide variety of fields, including basic developmental studies and clinical stem cell research.

  11. Olfactory sensor processing in neural networks: lessons from modeling the fruit fly antennal lobe

    Directory of Open Access Journals (Sweden)

    J. Henning Proske

    2012-02-01

    Full Text Available The insect olfactory system can be a model for artificial olfactory devices. In particular, Drosophila melanogaster due to its genetic tractability has yielded much information about the design and function of such systems in biology. In this study we investigate possible network topologies to separate representations of odors in the primary olfactory neuropil, the antennal lobe. In particular we compare networks based on stochastic and homogeneous connection weight distributions to connectivities that are based on the input correlations between the glomeruli in the antennal lobe. We show that moderate homogeneous inhibition implements a soft winner-take-all mechanism when paired with realistic input from a database of odor responses in receptor cells. The sparseness of representations increases with stronger inhibition. Excitation, on the other hand, pushes the representation of odors closer together thus making them harder to distinguish. We further analyze the relationship between different inhibitory network topologies and the properties of the receptor responses to different odors. We show that realistic input from the database has a relatively high entropy of activation values over all odors and receptors compared to the theoretical maximum. Furthermore, under conditions in which the information in the input is artificially decreased, networks with heterogeneous topologies based on the similarity of glomerular response profiles perform best. These results indicate that in order to arrive at the most beneficial representation for odor discrimination it is important to finely tune the strength of inhibition in combination with taking into account the properties of the available sensors.

  12. Cadmium Handling, Toxicity and Molecular Targets Involved during Pregnancy: Lessons from Experimental Models

    Science.gov (United States)

    Santoyo-Sánchez, Mitzi; Thévenod, Frank; Barbier, Olivier

    2017-01-01

    Even decades after the discovery of Cadmium (Cd) toxicity, research on this heavy metal is still a hot topic in scientific literature: as we wrote this review, more than 1440 scientific articles had been published and listed by the PubMed.gov website during 2017. Cadmium is one of the most common and harmful heavy metals present in our environment. Since pregnancy is a very particular physiological condition that could impact and modify essential pathways involved in the handling of Cd, the prenatal life is a critical stage for exposure to this non-essential element. To give the reader an overview of the possible mechanisms involved in the multiple organ toxic effects in fetuses after the exposure to Cd during pregnancy, we decided to compile some of the most relevant experimental studies performed in experimental models and to summarize the advances in this field such as the Cd distribution and the factors that could alter it (diet, binding-proteins and membrane transporters), the Cd-induced toxicity in dams (preeclampsia, fertility, kidney injury, alteration in essential element homeostasis and bone mineralization), in placenta and in fetus (teratogenicity, central nervous system, liver and kidney). PMID:28737682

  13. Coordination of tooth morphogenesis and neuronal development through tissue interactions: lessons from mouse models.

    Science.gov (United States)

    Luukko, Keijo; Kettunen, Päivi

    2014-07-15

    In addition to being an advantageous model to investigate general molecular mechanisms of organ formation, the tooth is a distinct target organ for peripheral nerve innervation. These nerves are required for the function and protection of the teeth and, as shown in fish, also for their regeneration. This review focuses on recent findings of the local tissue interactions and molecular signaling mechanisms that regulate the early nerve arrival and patterning of mouse mandibular molar tooth sensory innervation. Dental sensory nerve growth and patterning is a stepwise process that is intimately linked to advancing tooth morphogenesis. In particular, nerve growth factor and semaphorin 3A serve as essential functions during and are iteratively used at different stages of tooth innervation. The tooth germ controls development of its own nerve supply, and similar to the development of the tooth organ proper, tissue interactions between dental epithelial and mesenchymal tissues control the establishment of tooth innervation. Tgf-β, Wnt, and Fgf signaling, which regulate tooth formation, are implicated to mediate these interactions. Therefore, tissue interactions mediated by conserved signal families may constitute key mechanism for the integration of tooth organogenesis and development of its peripheral nerve supply. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Differential-geometric aspects of a nonholonomic Dirac mechanics: Lessons of a model quadratic in velocities

    Science.gov (United States)

    Pavlov, V. P.

    2014-03-01

    Faddeev and Vershik proposed the Hamiltonian and Lagrangian formulations of constrained mechanical systems that are invariant from the differential geometry standpoint. In both formulations, the description is based on a nondegenerate symplectic 2-form defined on a cotangent bundle T*Q (in the Hamiltonian formulation) or on a tangent bundle TQ (in the Lagrangian formulation), and constraints are sets of functions in involution on these manifolds. We demonstrate that this technique does not allow "invariantization" of the Dirac procedure of constraint "proliferation." We show this in an example of a typical quantum field model in which the original Lagrange function is a quadratic form in velocities with a degenerate coefficient matrix. We postulate that the initial phase space is a manifold where all arguments of the action functional including the Lagrange multipliers are defined. The Lagrange multipliers can then be naturally interpreted physically as velocities (in the Hamiltonian formulation) or momenta (in the Lagrangian formulation) related to "nonphysical" degrees of freedom. A quasisymplectic 2-form invariantly defined on such a manifold is degenerate. We propose new differential-geometric structures that allow formulating the Dirac procedure invariantly.

  15. Lessons learned from developing, implementing, and evaluating a model of community-driven nursing.

    Science.gov (United States)

    Nehls, N; Owen, B; Tipple, S; Vandermause, R

    2001-01-01

    The Helene Fuld Health Trust, HSBC Bank USA,Trustee has made generous contributions to the development of community-based nursing education. As a recipient of funds, faculty at the University ofWisconsin-Madison School of Nursing developed, implemented, and evaluated a pilot curriculum for undergraduate nursing students. The first phase of the project changed the landscape of community-based nursing education through faculty development. Unlike traditional approaches to faculty development, a resident expert model of faculty development based on dialogue was used. The second phase changed the landscape of teaching and learning community-based care through curricular and instructional revisions. Noteworthy changes were the creation of a curriculum responsive to both individual student and community needs, and recruitment of a cadre of teachers to enhance the cost-effectiveness of clinical education. The third phase changed the landscape of community-based nursing education through evaluation research. Several strategies were used to assess the project's usefulness, including interpretive phenomenological study of interview data and review of conventional outcome measures. Each phase of the project contributed to a new vision of community-based nursing education, a vision in which nursing as service is taught and learned.

  16. A classic model animal in the 21st century: recent lessons from the leech nervous system.

    Science.gov (United States)

    Wagenaar, Daniel A

    2015-11-01

    The medicinal leech (genus Hirudo) is a classic model animal in systems neuroscience. The leech has been central to many integrative studies that establish how properties of neurons and their interconnections give rise to the functioning of the animal at the behavioral level. Leeches exhibit several discrete behaviors (such as crawling, swimming and feeding) that are each relatively simple. Importantly, these behaviors can all be studied - at least at a basal level - in the isolated nervous system. The leech nervous system is particularly amenable to such studies because of its distributed nature; sensory processing and generation of behavior occur to a large degree in iterated segmental ganglia that each contain only ∼400 neurons. Furthermore, the neurons are relatively large and are arranged with stereotyped topography on the surface of the ganglion, which greatly facilitates their identification and accessibility. This Commentary provides an overview of recent work on the leech nervous system, with particular focus on circuits that underlie leech behavior. Studies that combine the unique features of the leech with modern optical and genetic techniques are also discussed. Thus, this Commentary aims to explain the continued appeal of the leech as an experimental animal in the 21st century.

  17. Immunogenetic basis of environmental lung disease: Lessons from the berylliosis model

    Energy Technology Data Exchange (ETDEWEB)

    Saltini, C.; Richeldi, L. [Univ. di Modena, Dept. di Scienze Mediche, Modena (Italy); Amicosante, M. [Univ. di Roma `Tor Vergata`, Dept. di Biologia, Roma (Italy); Franchi, A. [Univ. de Modena, Dept. Medicina Interna, Modena (Italy); Lombardi, G. [Hammersmith Hospital, Dept. of Immunology, London (United Kingdom)

    1998-12-01

    The role of genetic factors has been hypothesized in the pathogenesis of a number of chronic inflammatory lung diseases. The genes of the major histocompatibility complex (MHC) locus on human chromosome 6 have been identified as important determinants in diseases caused both by inorganic and organic compounds such as beryllium, gold, acid anhydrides, isocyanates and grass pollens. Since many environmental factors are the determinants of the immunopathogenesis of asthma, pulmonary granulomatous disorders, hypersensitivity pneumonitis and fibrotic lung disorders, an understanding of the interaction between environmental factors is crucial to epidemiology, prevention and treatment of these disorders. Berylliosis is an environmental chronic inflammatory disorder of the lung caused by inhalation of beryllium dusts. A human leukocyte antigen class II marker (HLA-DP Glu69) has been found to be strongly associated with the disease. In in vitro studies, the gene has been shown to play a direct role in the immunopathogenesis of the disease. In human studies, the gene has been shown to confer increased susceptibility to beryllium in exposed workers, thus suggesting that HLA gene markers may be used as epidemiological probes to identify population groups at higher risk of environmental lung diseases, to identify environmental levels of lung immunotoxicants that would be safe for the entire population and the prevent disease risk associated with occupation, manufactured products and the environment. Studies on the associations between human leukocyte antigens and chronic inflammatory lung disorders are reviewed in the context of the berylliosis model. (au) 123 refs.

  18. Hemolytic anemia repressed hepcidin level without hepatocyte iron overload: lesson from Günther disease model

    Science.gov (United States)

    Millot, Sarah; Delaby, Constance; Moulouel, Boualem; Lefebvre, Thibaud; Pilard, Nathalie; Ducrot, Nicolas; Ged, Cécile; Lettéron, Philippe; de Franceschi, Lucia; Deybach, Jean Charles; Beaumont, Carole; Gouya, Laurent; De Verneuil, Hubert; Lyoumi, Saïd; Puy, Hervé; Karim, Zoubida

    2017-01-01

    Hemolysis occurring in hematologic diseases is often associated with an iron loading anemia. This iron overload is the result of a massive outflow of hemoglobin into the bloodstream, but the mechanism of hemoglobin handling has not been fully elucidated. Here, in a congenital erythropoietic porphyria mouse model, we evaluate the impact of hemolysis and regenerative anemia on hepcidin synthesis and iron metabolism. Hemolysis was confirmed by a complete drop in haptoglobin, hemopexin and increased plasma lactate dehydrogenase, an increased red blood cell distribution width and osmotic fragility, a reduced half-life of red blood cells, and increased expression of heme oxygenase 1. The erythropoiesis-induced Fam132b was increased, hepcidin mRNA repressed, and transepithelial iron transport in isolated duodenal loops increased. Iron was mostly accumulated in liver and spleen macrophages but transferrin saturation remained within the normal range. The expression levels of hemoglobin-haptoglobin receptor CD163 and hemopexin receptor CD91 were drastically reduced in both liver and spleen, resulting in heme- and hemoglobin-derived iron elimination in urine. In the kidney, the megalin/cubilin endocytic complex, heme oxygenase 1 and the iron exporter ferroportin were induced, which is reminiscent of significant renal handling of hemoglobin-derived iron. Our results highlight ironbound hemoglobin urinary clearance mechanism and strongly suggest that, in addition to the sequestration of iron in macrophages, kidney may play a major role in protecting hepatocytes from iron overload in chronic hemolysis. PMID:28143953

  19. Microbial Life in Soil - Linking Biophysical Models with Observations

    Science.gov (United States)

    Or, Dani; Tecon, Robin; Ebrahimi, Ali; Kleyer, Hannah; Ilie, Olga; Wang, Gang

    2015-04-01

    Microbial life in soil occurs within fragmented aquatic habitats formed in complex pore spaces where motility is restricted to short hydration windows (e.g., following rainfall). The limited range of self-dispersion and physical confinement promote spatial association among trophically interdepended microbial species. Competition and preferences for different nutrient resources and byproducts and their diffusion require high level of spatial organization to sustain the functioning of multispecies communities. We report mechanistic modeling studies of competing multispecies microbial communities grown on hydrated surfaces and within artificial soil aggregates (represented by 3-D pore network). Results show how trophic dependencies and cell-level interactions within patchy diffusion fields promote spatial self-organization of motile microbial cells. The spontaneously forming patterns of segregated, yet coexisting species were robust to spatial heterogeneities and to temporal perturbations (hydration dynamics), and respond primarily to the type of trophic dependencies. Such spatially self-organized consortia may reflect ecological templates that optimize substrate utilization and could form the basic architecture for more permanent surface-attached microbial colonies. Hydration dynamics affect structure and spatial arrangement of aerobic and anaerobic microbial communities and their biogeochemical functions. Experiments with well-characterized artificial soil microbial assemblies grown on porous surfaces provide access to community dynamics during wetting and drying cycles detected through genetic fingerprinting. Experiments for visual observations of spatial associations of tagged bacterial species with known trophic dependencies on model porous surfaces are underway. Biophysical modeling provide a means for predicting hydration-mediated critical separation distances for activation of spatial self-organization. The study provides new modeling and observational tools

  20. Using observations to evaluate biosphere-atmosphere interactions in models

    Science.gov (United States)

    Green, Julia; Konings, Alexandra G.; Alemohammad, Seyed H.; Gentine, Pierre

    2017-04-01

    Biosphere-atmosphere interactions influence the hydrologic cycle by altering climate and weather patterns (Charney, 1975; Koster et al., 2006; Seneviratne et al., 2006), contributing up to 30% of precipitation and radiation variability in certain regions (Green et al., 2017). They have been shown to contribute to the persistence of drought in Europe (Seneviratne et al., 2006), as well as to increase rainfall in the Amazon (Spracklen et al., 2012). Thus, a true representation of these feedbacks in Earth System Models (ESMs) is crucial for accurate forecasting and planning. However, it has been difficult to validate the performance of ESMs since often-times surface and atmospheric flux data are scarce and/or difficult to observe. In this study, we use the results of a new global observational study (using remotely sensed solar-induced fluorescence to represent the biosphere flux) (Green et al., 2017) to determine how well a suite of 13 ESMs capture biosphere-atmosphere feedbacks. We perform a Conditional Multivariate Granger Causality analysis in the frequency domain with radiation, precipitation and temperature as atmospheric inputs and GPP as the biospheric input. Performing the analysis in the frequency domain allows for separation of feedbacks at different time-scales (subseasonal, seasonal or interannual). Our findings can be used to determine whether there is agreement between models, as well as, to pinpoint regions or time-scales of model bias or inaccuracy, which will provide insight on potential improvement. We demonstrate that in addition to the well-known problem of convective parameterization over land in models, the main issue in representing feedbacks between the land and the atmosphere is due to the misrepresentation of water stress. These results provide a direct quantitative assessment of feedbacks in models and how to improve them. References: Charney, J.G. Dynamics of deserts and drought in the Sahel. Quarterly Journal of the Royal Meteorological

  1. Lessons from a low-order coupled chemistry meteorology model and applications to a high-dimensional chemical transport model

    Science.gov (United States)

    Haussaire, Jean-Matthieu; Bocquet, Marc

    2016-04-01

    Atmospheric chemistry models are becoming increasingly complex, with multiphasic chemistry, size-resolved particulate matter, and possibly coupled to numerical weather prediction models. In the meantime, data assimilation methods have also become more sophisticated. Hence, it will become increasingly difficult to disentangle the merits of data assimilation schemes, of models, and of their numerical implementation in a successful high-dimensional data assimilation study. That is why we believe that the increasing variety of problems encountered in the field of atmospheric chemistry data assimilation puts forward the need for simple low-order models, albeit complex enough to capture the relevant dynamics, physics and chemistry that could impact the performance of data assimilation schemes. Following this analysis, we developped a low-order coupled chemistry meteorology model named L95-GRS [1]. The advective wind is simulated by the Lorenz-95 model, while the chemistry is made of 6 reactive species and simulates ozone concentrations. With this model, we carried out data assimilation experiments to estimate the state of the system as well as the forcing parameter of the wind and the emissions of chemical compounds. This model proved to be a powerful playground giving insights on the hardships of online and offline estimation of atmospheric pollution. Building on the results on this low-order model, we test advanced data assimilation methods on a state-of-the-art chemical transport model to check if the conclusions obtained with our low-order model still stand. References [1] Haussaire, J.-M. and Bocquet, M.: A low-order coupled chemistry meteorology model for testing online and offline data assimilation schemes, Geosci. Model Dev. Discuss., 8, 7347-7394, doi:10.5194/gmdd-8-7347-2015, 2015.

  2. On the viability of quintessential inflationary models from observational data

    CERN Document Server

    de Haro, Jaume

    2016-01-01

    Assuming that primordial density fluctuationas are nearly Gaussian, from a frequentist viewpoint, the two-dimensional marginalized joint coincidence contour in the plane $(n_s,r)$ (being $n_s$ the spectral index and $r$ the ratio of tensor to scalar perturbations), without the presence of running is usually used to test the viability of the inflationary models. The models that provide, between $50$ and $60$ e-folds, a curve in that plane, which lies outside the $95.5 \\%$ C.L are ruled out. I will basically argue that the this low number of e-folds is unjustified, and that models leading to a theoretical value of the running different from zero must be checked with observational data allowing the running. When both prescriptions are taken into account, dealing in the context of quintessential inflation, i.e. when the potential is a combination of an inflationary with a quintessential one that leads to a deflationary regime, inflationary models such as the quartic or the Higgs potential are allowed.

  3. On the viability of quintessential inflation models from observational data

    Science.gov (United States)

    de Haro, Jaume

    2017-01-01

    Assuming that primordial density fluctuations are nearly Gaussian, from a frequentist viewpoint, the two-dimensional marginalized joint coincidence contour in the plane (n_s,r) (being n_s the spectral index and r the ratio of tensor to scalar perturbations), without the presence of running is often used to test the viability of the inflationary models. The models that provide, between 50 and 60 e-folds, a curve in that plane lying outside the 95.5% C.L are ruled out. I will basically argue that, in quintessential inflation, this low number of e-folds is unjustified, and that models leading to a theoretical value of the running different from zero must be checked with observational data allowing the running. When both prescriptions are taken into account, dealing in the context of quintessential inflation, i.e. when the potential is a combination of an inflationary with a quintessential one that leads to a kination (also called deflation) regime, inflationary models such as the quartic or the Higgs potential are allowed.

  4. Spectral Models for Early Time SN 2011fe Observations

    CERN Document Server

    Baron, E; Sullivan, M; Hsiao, E; Ellis, R S; Gal-Yam, A; Howell, D A; Nugent, P E; Dominguez, I; Krisciunas, K; Phillips, M M; Suntzeff, N; Wang, L; Thomas, R C

    2015-01-01

    We use observed UV through near IR spectra to examine whether SN 2011fe can be understood in the framework of Branch-normal SNe Ia and to examine its individual peculiarities. As a benchmark, we use a delayed-detonation model with a progenitor metallicity of Z_solar/20. We study the sensitivity of features to variations in progenitor metallicity, the outer density profile, and the distribution of radioactive nickel. The effect of metallicity variations in the progenitor have a relatively small effect on the synthetic spectra. We also find that the abundance stratification of SN 2011fe resembles closely that of a delayed detonation model with a transition density that has been fit to other Branch-normal Type Ia supernovae. At early times, the model photosphere is formed in material with velocities that are too high, indicating that the photosphere recedes too slowly or that SN 2011fe has a lower specific energy in the outer ~0.1 M_sun than does the model. We discuss several explanations for the discrepancies. ...

  5. Constraints on surface evapotranspiration: implications for modeling and observations

    Science.gov (United States)

    Gentine, P.

    2015-12-01

    The continental hydrological cycle and especially evapotranspiration are constrained by additional factors such as the energy availability and the carbon cycle. As a results trying to understand and predict the surface hydrologic cycle in isolation might be highly unreliable. We present two examples were constraints induced by 1) radiation control through cloud albedo feedback and 2) carbon control on the surface water use efficiency are essential to correctly predict the seasonal hydrologic cycle. In the first example we show that correctly modeling diurnal and seasonal convection and the associated cloud-albedo feedback (through land-atmosphere and convection-large-scale circulation feedbacks) is essential to correctly model the surface hydrologic cycle in the Amazon, and to correct biases observed in all general circulation models. This calls for improved modeling of convection to correctly predict the tropical continental hydrologic cycle.In the second example we show that typical drought index based only on energy want water availability misses vegetation physiological and carbon feedback and cannot correctly represent the seasonal cycle of soil moisture stress. The typical Palmer Drought Stress Index is shown to be incapable of rejecting water stress in the future. This calls for new drought assessment metrics that may include vegetation and carbon feedback.

  6. Developing Pre-Service Teachers' Capacity in Teaching Science with Technology through Microteaching Lesson Study Approach

    Science.gov (United States)

    Zhou, George; Xu, Judy; Martinovic, Dragana

    2017-01-01

    In order to effectively use technology in teaching, teacher candidates need to develop technology related pedagogical content knowledge through being engaged in a process of discussion, modeling, practice, and reflection. Based on the examination of teacher candidates' lesson plan assignments, observations of their microteaching performance, and…

  7. The effects of pravastatin on the normal human placenta: Lessons from ex-vivo models

    Science.gov (United States)

    Swissa, Shani S.; Feinshtein, Valeria; Huleihel, Mahmoud; Holcberg, Gershon; Dukler, Doron

    2017-01-01

    Introduction Research in animal models and preliminary clinical studies in humans support the use of pravastatin for the prevention of preeclampsia. However, its use during pregnancy is still controversial due to limited data about its effect on the human placenta and fetus. Methods In the present study, human placental cotyledons were perfused in the absence or presence of pravastatin in the maternal reservoir (PraM). In addition, placental explants were treated with pravastatin for 5, 24 and 72 h under normoxia and hypoxia. We monitored the secretion of placental growth factor (PlGF), soluble fms-like tyrosine kinase-1 (sFlt-1), soluble endoglin (sEng), endothelial nitric oxide synthase (eNOS) expression and activation and the fetal vasoconstriction response to angiotensin-II. Results The concentrations of PlGF, sFlt-1 and sEng were not significantly altered by pravastatin in PraM cotyledons and in placental explants compared to control. Under hypoxic conditions, pravastatin decreased sFlt-1 concentrations. eNOS expression was significantly increased in PraM cotyledons but not in pravastatin-treated placental explants cultured under normoxia or hypoxia. eNOS phosphorylation was not significantly affected by pravastatin. The feto-placental vascular tone and the fetal vasoconstriction response to angiotensin-II, did not change following exposure of the maternal circulation to pravastatin. Conclusion We found that pravastatin does not alter the essential physiological functions of the placenta investigated in the study. The relevance of the study lays in the fact that it expands the current knowledge obtained thus far regarding the effect of the drug on the normal human placenta. This data is reassuring and important for clinicians that consider the treatment of high-risk patients with pravastatin, a treatment that exposes some normal pregnancies to the drug. PMID:28199380

  8. Observationally-Based Data/Model Metrics from the Southern Ocean Climate Model Atlas

    Science.gov (United States)

    Abell, J.; Russell, J. L.; Goodman, P. J.

    2015-12-01

    The Southern Ocean Climate Model Atlas makes available observationally-based standardized data/model metrics of the latest simulations of climate and projections of climate change from available climate models. Global climate model simulations differ greatly in the Southern Ocean, so the development of consistent, observationally-based metrics, by which to assess the fidelity of model simulations is essential. We will present metrics showing and quantifying the results of the modern day climate simulations over the Southern Ocean from models submitted as part of the CMIP5/IPCC-AR5 process. Our analysis will focus on the simulations of the temperature, salinity and carbon at various depths and along significant hydrographic sections. The models exhibit different skill levels with various metrics between models and also within individual models.

  9. Writing Lessons with Gavin Curtis.

    Science.gov (United States)

    Fu, Danling; Lamme, Linda

    2002-01-01

    Discusses a literature-inspired model of teaching writing and two scenarios of reading and writing connections in the classroom. Presents several reading and writing lessons drawn from the children's book "The Bat Boy and His Violin" by Gavin Curtis. Discusses Curtis' craft and demonstrates how to use this book to teach writing. Includes brief…

  10. In Old Pompeii. [Lesson Plan].

    Science.gov (United States)

    2001

    In this Web-based interdisciplinary lesson (involving social studies, geography, history, and language arts) students take a virtual field trip to the ruins of Pompeii to learn about everyday life in Roman times, then create a travelogue to attract visitors to the site and write an account of their field trip modeled on a description of Pompeii…

  11. Lessons in Ponapean.

    Science.gov (United States)

    Peace Corps, Washington, DC.

    This volume contains 35 beginning Ponapean lessons for native English speakers. Each lesson consists of a dialogue structured around an aspect of Ponapean grammar and substitution exercises designed for drill. Vocabulary is introduced in the substitution exercises. (CLK)

  12. CORAL: model for no observed adverse effect level (NOAEL).

    Science.gov (United States)

    Toropov, Andrey A; Toropova, Alla P; Pizzo, Fabiola; Lombardo, Anna; Gadaleta, Domenico; Benfenati, Emilio

    2015-08-01

    The in vivo repeated dose toxicity (RDT) test is intended to provide information on the possible risk caused by repeated exposure to a substance over a limited period of time. The measure of the RDT is the no observed adverse effect level (NOAEL) that is the dose at which no effects are observed, i.e., this endpoint indicates the safety level for a substance. The need to replace in vivo tests, as required by some European Regulations (registration, evaluation authorization and restriction of chemicals) is leading to the searching for reliable alternative methods such as quantitative structure-activity relationships (QSAR). Considering the complexity of the RDT endpoint, for which data quality is limited and depends anyway on the study design, the development of QSAR for this endpoint is an attractive task. Starting from a dataset of 140 organic compounds with NOAEL values related to oral short term toxicity in rats, we developed a QSAR model based on optimal descriptors calculated with simplified molecular input-line entry systems and the graph of atomic orbitals by the Monte Carlo method, using CORAL software. Three different splits into the training, calibration, and validation sets are studied. The mechanistic interpretation of these models in terms of molecular fragment with positive or negative contributions to the endpoint is discussed. The probabilistic definition for the domain of applicability is suggested.

  13. Observation

    Science.gov (United States)

    Patell, Hilla

    2016-01-01

    In order to achieve the goal of observation, preparation of the adult, the observer, is necessary. This preparation, says Hilla Patell, requires us to "have an appreciation of the significance of the child's spontaneous activities and a more thorough understanding of the child's needs." She discusses the growth of both the desire to…

  14. Observation

    Science.gov (United States)

    Kripalani, Lakshmi A.

    2016-01-01

    The adult who is inexperienced in the art of observation may, even with the best intentions, react to a child's behavior in a way that hinders instead of helping the child's development. Kripalani outlines the need for training and practice in observation in order to "understand the needs of the children and...to understand how to remove…

  15. On radial heliospheric magnetic fields: Voyager 2 observation and model

    Science.gov (United States)

    Wang, C.; Richardson, J. D.; Burlaga, L. F.; Ness, N. F.

    2003-05-01

    The heliospheric magnetic field (HMF) direction, on average, conforms well to the Parker spiral. However, numerous examples of events where the HMF is oriented in near-radial directions for many hours have been reported on the basis of observations inside 5 AU from spacecraft such as ISEE-3 and Ulysses. The magnetic field data observed by Voyager 2 from launch in 1977 through the end of 1982 (i.e., between 1 and ˜10 AU) were searched for all instances of radial fields with durations of 6 hours or more. Radial fields of significant durations at large distances are unusual as the Parker spiral is very tightly wound. The radial HMF events in the inner heliosphere typically occur at times when the solar wind speed is declining gradually, while they tend to be associated with steady wind speeds at distances beyond ˜6 AU. The durations of these events appear to be independent of distance and solar cycle, with an average duration of ˜11 hours. They generally are not associated with interplanetary coronal mass ejections (ICMEs). Possible generation mechanisms of the radial field events related to speed variations near the Sun are investigated by use of a MHD model. We find that a noticeable low-speed plateau of limited duration in solar wind speed near the Sun can produce radial field events having durations of the order of 10 hours in the heliosphere as observed by Voyager 2.

  16. Whistler emissions in the magnetosphere - satellite observations and numerical modeling

    Science.gov (United States)

    Chum, J.; Jiricek, F.; Shklyar, D. R.

    The investigation of ionospheric and magnetospheric wave phenomena related to lightning strokes began from classical research by Eckersley (Nature, Lond., 135, 104, 1935) and Storey (Phil. Trans. Roy. Soc. Lond., A246, 908, 113-141, 1953) among others, and it has continued up to the present. VLF spectrograms from the MAGION 4 and MAGION 5 satellites contain most of the known types of VLF emissions, as well as some new ones not discussed previously. A partial list of the observed emissions involving nonducted propagation includes: magnetospherically reflected (MR) whistlers (and their subclass, Nu whistlers) predicted by Kimura (Radio Sci., 1, 3, 269-283, 1966) and then found by Smith and Angerami in the spectrograms of wave data from OGO 1 and 3 (J. Geophys. Res., 73, 1, 1-20, 1968); lower hybrid resonance (LHR) noise bands; LHR whistlers and LHR spherics; and oblique noise bands above the local LHR frequency. Recently, a new line of investigation was initiated by numerical modeling of VLF spectrograms of nonducted emissions caused by lightning. For such emissions, as observed by a satellite in the magnetosphere, the spectrograms depend on several factors: the properties of the source, the geomagnetic field structure and the cold plasma distribution which jointly influence the wave propagation, and the resonant interactions of the waves with energetic particles. Therefore, numerical modeling of spectrograms and comparing them with real ones may serve as an indirect tool for investigating the factors mentioned above and any other processes that affect the spectrograms. This tool is especially effective when the source of the emission is known, in particular with lightning-induced emissions. The main features of our numerical method for modeling spectrograms include: a) representation of the wave field as the sum of wave packets treatable by geometrical optics; b) construction of a frequency-time plot based on the notion of a group front; c) calculation of the

  17. Models of Warm Jupiter Atmospheres: Observable Signatures of Obliquity

    Science.gov (United States)

    Rauscher, Emily

    2017-09-01

    We present three-dimensional atmospheric circulation models of a hypothetical “warm Jupiter” planet, for a range of possible obliquities from 0° to 90°. We model a Jupiter-mass planet on a 10 day orbit around a Sun-like star, since this hypothetical planet sits at the boundary between planets for which we expect that tidal forces should have aligned their rotation axes with their orbital axes (i.e., ones with zero obliquity) and planets whose timescale for tidal alignment is longer than the typical age of an exoplanet system. In line with observational progress, which is pushing atmospheric characterization for planets on longer orbital periods, we calculate the observable signatures of obliquity for a transiting warm Jupiter: in orbital phase curves of thermal emission and in the hemispheric flux gradients that could be measured by eclipse mapping. For both of these predicted measurements, the signal that we would see depends strongly on our viewing geometry relative to the orientation of the planet’s rotation axis, and we thoroughly identify the degeneracies that result. We compare these signals to the predicted sensitivities of current and future instruments and determine that the James Webb Space Telescope should be able to constrain the obliquities of nearby warm Jupiters to be small (if ≤slant 10^\\circ ) or to directly measure them if significantly non-zero (≥slant 30^\\circ ) using the technique of eclipse mapping. For a bright target and assuming photon-limited precision, this could be done with a single secondary eclipse observation.

  18. A Lesson Plan on El Salvador.

    Science.gov (United States)

    Interracial Books for Children Bulletin, 1982

    1982-01-01

    Presents background information on Salvadoran history, politics, and religion. Provides a model lesson plan designed to help high school students to understand events leading to the current conflict in El Salvador and the rest of Central America. (Author/GC)

  19. General Description of Fission Observables: GEF Model Code

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, K.-H. [CENBG, CNRS/IN2 P3, Chemin du Solarium, B.P. 120, F-33175 Gradignan (France); Jurado, B., E-mail: jurado@cenbg.in2p3.fr [CENBG, CNRS/IN2 P3, Chemin du Solarium, B.P. 120, F-33175 Gradignan (France); Amouroux, C. [CEA, DSM-Saclay (France); Schmitt, C., E-mail: schmitt@ganil.fr [GANIL, Bd. Henri Becquerel, B.P. 55027, F-14076 Caen Cedex 05 (France)

    2016-01-15

    The GEF (“GEneral description of Fission observables”) model code is documented. It describes the observables for spontaneous fission, neutron-induced fission and, more generally, for fission of a compound nucleus from any other entrance channel, with given excitation energy and angular momentum. The GEF model is applicable for a wide range of isotopes from Z = 80 to Z = 112 and beyond, up to excitation energies of about 100 MeV. The results of the GEF model are compared with fission barriers, fission probabilities, fission-fragment mass- and nuclide distributions, isomeric ratios, total kinetic energies, and prompt-neutron and prompt-gamma yields and energy spectra from neutron-induced and spontaneous fission. Derived properties of delayed neutrons and decay heat are also considered. The GEF model is based on a general approach to nuclear fission that explains a great part of the complex appearance of fission observables on the basis of fundamental laws of physics and general properties of microscopic systems and mathematical objects. The topographic theorem is used to estimate the fission-barrier heights from theoretical macroscopic saddle-point and ground-state masses and experimental ground-state masses. Motivated by the theoretically predicted early localisation of nucleonic wave functions in a necked-in shape, the properties of the relevant fragment shells are extracted. These are used to determine the depths and the widths of the fission valleys corresponding to the different fission channels and to describe the fission-fragment distributions and deformations at scission by a statistical approach. A modified composite nuclear-level-density formula is proposed. It respects some features in the superfluid regime that are in accordance with new experimental findings and with theoretical expectations. These are a constant-temperature behaviour that is consistent with a considerably increased heat capacity and an increased pairing condensation energy that is

  20. Glider observations and modeling of sediment transport in Hurricane Sandy

    Science.gov (United States)

    Miles, Travis; Seroka, Greg; Kohut, Josh; Schofield, Oscar; Glenn, Scott

    2015-03-01

    Regional sediment resuspension and transport are examined as Hurricane Sandy made landfall on the Mid-Atlantic Bight (MAB) in October 2012. A Teledyne-Webb Slocum glider, equipped with a Nortek Aquadopp current profiler, was deployed on the continental shelf ahead of the storm, and is used to validate sediment transport routines coupled to the Regional Ocean Modeling System (ROMS). The glider was deployed on 25 October, 5 days before Sandy made landfall in southern New Jersey (NJ) and flew along the 40 m isobath south of the Hudson Shelf Valley. We used optical and acoustic backscatter to compare with two modeled size classes along the glider track, 0.1 and 0.4 mm sand, respectively. Observations and modeling revealed full water column resuspension for both size classes for over 24 h during peak waves and currents, with transport oriented along-shelf toward the southwest. Regional model predictions showed over 3 cm of sediment eroded on the northern portion of the NJ shelf where waves and currents were the highest. As the storm passed and winds reversed from onshore to offshore on the southern portion of the domain waves and subsequently orbital velocities necessary for resuspension were reduced leading to over 3 cm of deposition across the entire shelf, just north of Delaware Bay. This study highlights the utility of gliders as a new asset in support of the development and verification of regional sediment resuspension and transport models, particularly during large tropical and extratropical cyclones when in situ data sets are not readily available.

  1. Modeling, Simulation, and Operations Analysis in Afghanistan and Iraq: Operational Vignettes, Lessons Learned, and a Survey of Selected Efforts

    Science.gov (United States)

    2014-01-01

    John A. Nagl, Counterinsurgency Lessons from Malaya and Vietnam: Learning to Eat Soup with a Knife, West- port, Conn.: Praeger Publishers, 2002; Thomas...Their Principles and Practice, 3rd Edition, Lincoln, Neb.: University of Nebraska Press, 1996 (Original Publication 1896). Campbell , Jason, Michael E...to Eat Soup with a Knife, Westport, Conn.: Praeger Publishers, 2002. Nakashima, Ellen, and Craig Whitlock, “With Air Force’s Gorgon Drone, ‘We Can

  2. Europlanet/IDIS: Combining Diverse Planetary Observations and Models

    Science.gov (United States)

    Schmidt, Walter; Capria, Maria Teresa; Chanteur, Gerard

    2013-04-01

    Planetary research involves a diversity of research fields from astrophysics and plasma physics to atmospheric physics, climatology, spectroscopy and surface imaging. Data from all these disciplines are collected from various space-borne platforms or telescopes, supported by modelling teams and laboratory work. In order to interpret one set of data often supporting data from different disciplines and other missions are needed while the scientist does not always have the detailed expertise to access and utilize these observations. The Integrated and Distributed Information System (IDIS) [1], developed in the framework of the Europlanet-RI project, implements a Virtual Observatory approach ([2] and [3]), where different data sets, stored in archives around the world and in different formats, are accessed, re-formatted and combined to meet the user's requirements without the need of familiarizing oneself with the different technical details. While observational astrophysical data from different observatories could already earlier be accessed via Virtual Observatories, this concept is now extended to diverse planetary data and related model data sets, spectral data bases etc. A dedicated XML-based Europlanet Data Model (EPN-DM) [4] was developed based on data models from the planetary science community and the Virtual Observatory approach. A dedicated editor simplifies the registration of new resources. As the EPN-DM is a super-set of existing data models existing archives as well as new spectroscopic or chemical data bases for the interpretation of atmospheric or surface observations, or even modeling facilities at research institutes in Europe or Russia can be easily integrated and accessed via a Table Access Protocol (EPN-TAP) [5] adapted from the corresponding protocol of the International Virtual Observatory Alliance [6] (IVOA-TAP). EPN-TAP allows to search catalogues, retrieve data and make them available through standard IVOA tools if the access to the archive

  3. MILES FORMULAE FOR BOOLEAN MODELS OBSERVED ON LATTICES

    Directory of Open Access Journals (Sweden)

    Joachim Ohser

    2011-05-01

    Full Text Available The densities of the intrinsic volumes – in 3D the volume density, surface density, the density of the integral of the mean curvature and the density of the Euler number – are a very useful collection of geometric characteristics of random sets. Combining integral and digital geometry we develop a method for efficient and simultaneous calculation of the intrinsic volumes of random sets observed in binary images in arbitrary dimensions. We consider isotropic and reflection invariant Boolean models sampled on homogeneous lattices and compute the expectations of the estimators of the intrinsic volumes. It turns out that the estimator for the surface density is proved to be asymptotically unbiased and thusmultigrid convergent for Boolean models with convex grains. The asymptotic bias of the estimators for the densities of the integral of the mean curvature and of the Euler number is assessed for Boolean models of balls of random diameters. Miles formulae with corresponding correction terms are derived for the 3D case.

  4. Suppressing Electroweak Precision Observables in 5D Warped Models

    CERN Document Server

    Cabrer, Joan A; Quiros, Mariano

    2011-01-01

    We elaborate on a recently proposed mechanism to suppress large contributions to the electroweak precision observables in five dimensional (5D) warped models, without the need for an extended 5D gauge sector. The main ingredient is a modification of the AdS metric in the vicinity of the infrared (IR) brane corresponding to a strong deviation from conformality in the IR of the 4D holographic dual. We compute the general low energy effective theory of the 5D warped Standard Model, emphasizing additional IR contributions to the wave function renormalization of the light Higgs mode. We also derive expressions for the S and T parameters as a function of a generic 5D metric and zero-mode wave functions. We give an approximate formula for the mass of the radion that works even for strong deviation from the AdS background. We proceed to work out the details of an explicit model and derive bounds for the first KK masses of the various bulk fields. The radion is the lightest new particle although its mass is already at...

  5. K-Pg Wildfires: modeling, experiments and observations

    Science.gov (United States)

    Morgan, J.; Artemieva, N.; Belcher, C.; Hadden, R.; Rein, G.; Goldin, T.

    2013-09-01

    The discovery of soot in K-Pg boundary clays [1] started a long debate about whether the asteroid impact ignited global wildfires. The K-Pg layer is formed from material ejected from the Chicxulub site, which travelled at hypervelocities around the world. When such ejecta re-enters the Earth's atmosphere it decelerates and heats up, and delivers a pulse of radiation to the Earth's surface. Recent estimates of the radiation associated with ejecta re-entry [2] are argued to be large enough to have ignited fires globally [3]. Here, we present new 3D models of the thermal pulse that takes in to account the asymmetric distribution of ejecta, which depends on the angle and direction of the Chicxulub impact [4]. We have replicated some of the modeled thermal pulses with a Fire propagation Apparatus (FPA), to investigate their effect on both dry and living plant matter. The models, experiments and observational data are consistent with some wildfires being ignited as a direct result of the impact, but the mass flux of ejecta at sites uprange of Chicxulub is too low to ignite even the most susceptible of plant matter.

  6. Modelling variability in black hole binaries: linking simulations to observations

    CERN Document Server

    Ingram, Adam

    2011-01-01

    Black hole accretion flows show rapid X-ray variability. The Power Spectral Density (PSD) of this is typically fit by a phenomenological model of multiple Lorentzians for both the broad band noise and Quasi-Periodic Oscillations (QPOs). Our previous paper (Ingram & Done 2011) developed the first physical model for the PSD and fit this to observational data. This was based on the same truncated disc/hot inner flow geometry which can explain the correlated properties of the energy spectra. This assumes that the broad band noise is from propagating fluctuations in mass accretion rate within the hot flow, while the QPO is produced by global Lense-Thirring precession of the same hot flow. Here we develop this model, making some significant improvements. Firstly we specify that the viscous frequency (equivalently, surface density) in the hot flow has the same form as that measured from numerical simulations of precessing, tilted accretion flows. Secondly, we refine the statistical techniques which we use to fit...

  7. 泛在学习环境下的微课信息模型构建%On the Construction of Micro-lesson Information Model in U-learning Environment

    Institute of Scientific and Technical Information of China (English)

    彭勤涛

    2015-01-01

    With the development of information technology, e-learning is developing rapidly, and micro-lesson, with its mi-cro and exquisite features, has been attached to more and more importance. From the perspective of information, this paper rede-fined micro-lesson, analyzed the defects of the current mi-cro-lesson information model, put forward the micro-lesson in-formation framework and micro-lesson information model based on social interaction in the background of u-learning, and speci-fied its structure.%随着信息技术发展,数字化学习资源快速发展,微课以其小而精悍的特点日益受到关注。本文从信息角度重新定义微课,分析了当前微课资源信息模型的缺陷,提出了适合泛在学习背景下的社交互动式的微课信息框架及微课的信息模型,并详细说明了其结构。

  8. PENINGKATAN PROFESIONALISME GURU DAN KUALITAS PEMBELAJARAN BIOLOGI DI SEKOLAH MELALUI LESSON STUDY

    Directory of Open Access Journals (Sweden)

    Siti Sriyati

    2015-01-01

    Full Text Available This research was done to investigate impact of lesson study in order to improve teachers professionalism and the quality of teaching learning process in Biology. Although lesson study has been conducted since the year of 2005 at numerous schools in Bandung, information on how far such activity does give impact to teacher as instructor and teacher as observer has not been uncovered. The research was undertaken by spreading questions to the instructor as well as the observer. Furthermore, quality of teaching learning process in the school was observed at SMP Lab. School and SMA Lab. School UPI. The research resulted in insight that through lesson study, teachers both served as instructor and observer can improve such competency as pedagogy, professional, personality, social as clearly indicated in “ UU Guru dan Dosen No. 14 Tahun 2005”. However, for those teachers as observers, competency of pedagogy has not been significantly explored. Both the instructors and observers have not entirely user their KBM (teaching learning process to conduct PTK (classroom action research. In addition, the KBM conducted in lesson study can improve quality of teaching learning process in the classroom based upon good interaction between students and teachers as well as among students (in or out the groups during discussion and percentage of students who actively learned. Through model teaching learning process developed in lesson study, students are trained to improve their ability in scientific work and to connect biology concept to its application in daily life using local materials. Keyword : Teacher’s professionalism, lesson study, KBM (Teaching learning process,PTK (Classroom action research

  9. Further ALMA observations and detailed modeling of the Red Rectangle

    Science.gov (United States)

    Bujarrabal, V.; Castro-Carrizo, A.; Alcolea, J.; Santander-García, M.; Van Winckel, H.; Sánchez Contreras, C.

    2016-01-01

    Aims We aim to study the rotating and expanding gas in the Red Rectangle, which is a well known object that recently left the asymptotic giant branch (AGB) phase. We analyze the properties of both components and the relation between them. Rotating disks have been very elusive in post-AGB nebulae, in which gas is almost always found to be in expansion. Methods We present new high-quality ALMA observations of C17O J=6−5 and H13CN J=4−3 line emission and results from a new reduction of already published 13CO J=3−2 data. A detailed model fitting of all the molecular line data, including previous maps and single-dish observations of lines of CO, CII, and CI, was performed using a sophisticated code that includes an accurate nonlocal treatment of radiative transfer in 2D. These observations (of low- and high-opacity lines requiring various degrees of excitation) and the corresponding modeling allowed us to deepen the analysis of the nebular properties. We also stress the uncertainties, particularly in the determination of the boundaries of the CO-rich gas and some properties of the outflow. Results We confirm the presence of a rotating equatorial disk and an outflow, which is mainly formed of gas leaving the disk. The mass of the disk is ~ 0.01 M⊙, and that of the CO-rich outflow is around ten times smaller. High temperatures of ≳ 100 K are derived for most components. From comparison of the mass values, we roughly estimate the lifetime of the rotating disk, which is found to be of about 10000 yr. Taking data of a few other post-AGB composite nebulae into account, we find that the lifetimes of disks around post-AGB stars typically range between 5000 and more than 20000 yr. The angular momentum of the disk is found to be high, ~ 9 M⊙ AU km s−1, which is comparable to that of the stellar system at present. Our observations of H13CN show a particularly wide velocity dispersion and indicate that this molecule is only abundant in the inner Keplerian disk, at

  10. Observation and modelling of HOx radicals in a boreal forest

    Directory of Open Access Journals (Sweden)

    K. Hens

    2014-08-01

    Full Text Available Measurements of OH and HO2 radicals were conducted in a pine-dominated forest in southern Finland during the HUMPPA-COPEC-2010 (Hyytiälä United Measurements of Photochemistry and Particles in Air – Comprehensive Organic Precursor Emission and Concentration study field campaign in summer 2010. Simultaneous side-by-side measurements of hydroxyl radicals were conducted with two instruments using chemical ionization mass spectrometry (CIMS and laser-induced fluorescence (LIF, indicating small systematic disagreement, OHLIF / OHCIMS = (1.31 ± 0.14. Subsequently, the LIF instrument was moved to the top of a 20 m tower, just above the canopy, to investigate the radical chemistry at the ecosystem–atmosphere interface. Comprehensive measurements including observations of many volatile organic compounds (VOCs and the total OH reactivity were conducted and analysed using steady-state calculations as well as an observationally constrained box model. Production rates of OH calculated from measured OH precursors are consistent with those derived from the steady-state assumption and measured total OH loss under conditions of moderate OH reactivity. The primary photolytic sources of OH contribute up to one-third to the total OH production. OH recycling, which occurs mainly by HO2 reacting with NO and O3, dominates the total hydroxyl radical production in this boreal forest. Box model simulations agree with measurements for hydroxyl radicals (OHmod. / OHobs. = 1.00 ± 0.16, while HO2 mixing ratios are significantly under-predicted (HO2mod. / HO2obs. = 0.3 ± 0.2, and simulated OH reactivity does not match the observed OH reactivity. The simultaneous under-prediction of HO2 and OH reactivity in periods in which OH concentrations were simulated realistically suggests that the missing OH reactivity is an unaccounted-for source of HO2. Detailed analysis of the HOx production, loss, and recycling pathways suggests that in periods of high total OH reactivity

  11. Radar observations and shape model of asteroid 16 Psyche

    Science.gov (United States)

    Shepard, Michael K.; Richardson, James; Taylor, Patrick A.; Rodriguez-Ford, Linda A.; Conrad, Al; de Pater, Imke; Adamkovics, Mate; de Kleer, Katherine; Males, Jared R.; Morzinski, Katie M.; Close, Laird M.; Kaasalainen, Mikko; Viikinkoski, Matti; Timerson, Bradley; Reddy, Vishnu; Magri, Christopher; Nolan, Michael C.; Howell, Ellen S.; Benner, Lance A. M.; Giorgini, Jon D.; Warner, Brian D.; Harris, Alan W.

    2017-01-01

    Using the S-band radar at Arecibo Observatory, we observed 16 Psyche, the largest M-class asteroid in the main belt. We obtained 18 radar imaging and 6 continuous wave runs in November and December 2015, and combined these with 16 continuous wave runs from 2005 and 6 recent adaptive-optics (AO) images (Drummond et al., 2016) to generate a three-dimensional shape model of Psyche. Our model is consistent with a previously published AO image (Hanus et al., 2013) and three multi-chord occultations. Our shape model has dimensions 279 × 232 × 189 km (± 10%), Deff = 226 ± 23 km, and is 6% larger than, but within the uncertainties of, the most recently published size and shape model generated from the inversion of lightcurves (Hanus et al., 2013). Psyche is roughly ellipsoidal but displays a mass-deficit over a region spanning 90° of longitude. There is also evidence for two ∼50-70 km wide depressions near its south pole. Our size and published masses lead to an overall bulk density estimate of 4500 ± 1400 kgm-3. Psyche's mean radar albedo of 0.37 ± 0.09 is consistent with a near-surface regolith composed largely of iron-nickel and ∼40% porosity. Its radar reflectivity varies by a factor of 1.6 as the asteroid rotates, suggesting global variations in metal abundance or bulk density in the near surface. The variations in radar albedo appear to correlate with large and small-scale shape features. Our size and Psyche's published absolute magnitude lead to an optical albedo of pv = 0.15 ± 0.03, and there is evidence for albedo variegations that correlate with shape features.

  12. Asteroid 16 Psyche: Radar Observations and Shape Model

    Science.gov (United States)

    Shepard, Michael K.; Richardson, James E.; Taylor, Patrick A.; Rodriguez-Ford, Linda A.; Conrad, Al; de Pater, Imke; Adamkovics, Mate; de Kleer, Katherine R.; Males, Jared; Morzinski, Kathleen M.; Miller Close, Laird; Kaasalainen, Mikko; Viikinkoski, Matti; Timerson, Bradley; Reddy, Vishnu; Magri, Christopher; Nolan, Michael C.; Howell, Ellen S.; Warner, Brian D.; Harris, Alan W.

    2016-10-01

    We observed 16 Psyche, the largest M-class asteroid in the main belt, using the S-band radar at Arecibo Observatory. We obtained 18 radar imaging and 6 continuous wave runs in November and December 2015, and combined these with 16 continuous wave runs from 2005 and 6 recent adaptive-optics (AO) images to generate a three-dimensional shape model of Psyche. Our model is consistent with a previously published AO image [Hanus et al. Icarus 226, 1045-1057, 2013] and three multi-chord occultations. Our shape model has dimensions 279 x 232 x 189 km (±10%), Deff = 226 ± 23 km, and is 6% larger than, but within the uncertainties of, the most recently published size and shape model generated from the inversion of lightcurves [Hanus et al., 2013]. Psyche is roughly ellipsoidal but displays a mass-deficit over a region spanning 90° of longitude. There is also evidence for two ~50-70 km wide depressions near its south pole. Our size and published masses lead to an overall bulk density estimate of 4500 ± 1400 kg m-3. Psyche's mean radar albedo of 0.37 ± 0.09 is consistent with a near-surface regolith composed largely of iron-nickel and ~40% porosity. Its radar reflectivity varies by a factor of 1.6 as the asteroid rotates, suggesting global variations in metal abundance or bulk density in the near surface. The variations in radar albedo appear to correlate with large and small-scale shape features. Our size and Psyche's published absolute magnitude lead to an optical albedo of pv = 0.15 ± 0.03, and there is evidence for albedo variegations that correlate with shape features.

  13. Neotectonic stresses in Fennoscandia: field observations and modelling

    Science.gov (United States)

    Pascal, Christophe

    2013-04-01

    present-day stress magnitudes are far to be uniform in Scandinavia. For example the modelling predicts that the topography of the southern Norwegian Mountains creates Gravitational Potential Energy (GPE) levels higher than the ones characterising the surrounding regions. This results in significant buoyancy forces competing locally with the regional ridge-push. GPE decreases almost gradually towards the Gulf of Bothnia where strong compressive stresses are predicted. A local departure from the regional NW-SE trend for the maximum horizontal stress axes is simulated in Trøndelag, Norway. This local stress deviation is supported by stress-relief observations and in situ stress measurements. Our modelling suggests that it results from the combined effects of the weak rheology of the Møre-Trøndelag Fault Complex and topographic stresses associated with the southern Norwegian Scandes mountains.

  14. Adaptive mixture observation models for multiple object tracking

    Institute of Scientific and Technical Information of China (English)

    CUI Peng; SUN LiFeng; YANG ShiQiang

    2009-01-01

    Multiple object tracking (MOT) poses many difficulties to conventional well-studied single object track-ing (SOT) algorithms, such as severe expansion of configuration space, high complexity of motion con-ditions, and visual ambiguities among nearby targets, among which the visual ambiguity problem is the central challenge. In this paper, we address this problem by embedding adaptive mixture observation models (AMOM) into a mixture tracker which is implemented in Particle Filter framework. In AMOM, the extracted multiple features for appearance description are combined according to their discriminative power between ambiguity prone objects, where the discriminability of features are evaluated by online entropy-based feature selection techniques. The induction of AMOM can help to surmount the Incapa-bility of conventional mixture tracker in handling object occlusions, and meanwhile retain its merits of flexibility and high efficiency. The final experiments show significant improvement in MOT scenarios compared with other methods.

  15. Gaussian estimation for discretely observed Cox-Ingersoll-Ross model

    Science.gov (United States)

    Wei, Chao; Shu, Huisheng; Liu, Yurong

    2016-07-01

    This paper is concerned with the parameter estimation problem for Cox-Ingersoll-Ross model based on discrete observation. First, a new discretized process is built based on the Euler-Maruyama scheme. Then, the parameter estimators are obtained by employing the maximum likelihood method and the explicit expressions of the error of estimation are given. Subsequently, the consistency property of all parameter estimators are proved by applying the law of large numbers for martingales, Holder's inequality, B-D-G inequality and Cauchy-Schwarz inequality. Finally, a numerical simulation example for estimators and the absolute error between estimators and true values is presented to demonstrate the effectiveness of the estimation approach used in this paper.

  16. Photometric Observation and Modeling Study of the Asteroid (26) Proserpina

    Science.gov (United States)

    Bin, Li; Hai-bin, Zhao; Xin, Wang

    2016-07-01

    We present the new CCD observations on the asteroid (26) Proserpina performed between 2011 December and 2012 February. Based upon the new observations, a synodic rotation period of (13.107 ± 0.002) h is obtained. Using all the light curves available sofar, the rotation vector, rotation period, and the shape model of the asteroid are determined with the convex-hull inversion method. Further more, a bootstrap method is applied to estimating the uncertainties of the rotation parameters. We derive a pair of possible rotation poles for (26) Proserpina, and believe that it has a retrograde rotation. The rotation poles are determined to be λ1 = 90.8° ± 1.4°, β1 = -53.1° ± 3.2°, and λ2 = 259.3° ± 2.2°, β2 = -62.0° ± 2.0°. The sidereal rotation periods corresponding to the two poles are almost the same as (13.109777 ± 3.8 × 10-6) h. And corresponding to this pair of rotation poles, the convex-hull shapes of the asteroid are the mirror images of each other.

  17. Modelling Agro-Met Station Observations Using Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Prashant Kumar

    2014-01-01

    Full Text Available The present work discusses the development of a nonlinear data-fitting technique based on genetic algorithm (GA for the prediction of routine weather parameters using observations from Agro-Met Stations (AMS. The algorithm produces the equations that best describe the temporal evolutions of daily minimum and maximum near-surface (at 2.5-meter height air temperature and relative humidity and daily averaged wind speed (at 10-meter height at selected AMS locations. These enable the forecasts of these weather parameters, which could have possible use in crop forecast models. The forecast equations developed in the present study use only the past observations of the above-mentioned parameters. This approach, unlike other prediction methods, provides explicit analytical forecast equation for each parameter. The predictions up to 3 days in advance have been validated using independent datasets, unknown to the training algorithm, with impressive results. The power of the algorithm has also been demonstrated by its superiority over persistence forecast used as a benchmark.

  18. ENSO Amplitude Change in Observation and Coupled Models

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qiong; GUAN Yue; YANG Haijun

    2008-01-01

    Observations show that the tropical El Nino-Southern Oscillation (ENSO) variability, after removing both the long term trend and decadal change of the background climate, has been enhanced by as much as 60% during the past 50 years. This shift in ENSO amplitude can be related to mean state changes in global climate. Past global warming has caused a weakening of the Walker circulation over the equatorial Indo-Pacific oceans, as well as a weakening of the trade winds and a reduction in the equatorial upwelling. These changes in tropical climatology play as stabilizing factors of the tropical coupling system. However, the shallower and strengthening thermocline in the equatorial Pacific increases the SST sensitivity to thermocline and wind stress variabilities and tend to destabilize the tropical coupling system. Observations suggest that the destabilizing factors, such as the strengthening thermocline, may have overwhelmed the stabilizing effects of the atmosphere, and played a deterministic role in the enhanced ENSO variability, at least during the past half century. This is different from the recent assessment of IPCC-AR4 coupled models.

  19. TIME-IGGCAS model validation:Comparisons with empirical models and observations

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The TIME-IGGCAS (Theoretical Ionospheric Model of the Earth in Institute of Ge- ology and Geophysics, Chinese Academy of Sciences) has been developed re- cently on the basis of previous works. To test its validity, we have made compari- sons of model results with other typical empirical ionospheric models (IRI, NeQuick-ITUR, and TItheridge temperature models) and multi-observations (GPS, Ionosondes, Topex, DMSP, FORMOSAT, and CHAMP) in this paper. Several conclu- sions are obtained from our comparisons. The modeled electron density and elec- tron and ion temperatures are quantitatively in good agreement with those of em- pirical models and observations. TIME-IGGCAS can model the electron density variations versus several factors such as local time, latitude, and season very well and can reproduce most anomalistic features of ionosphere including equatorial anomaly, winter anomaly, and semiannual anomaly. These results imply a good base for the development of ionospheric data assimilation model in the future. TIME-IGGCAS underestimates electron temperature and overestimates ion tem- perature in comparison with either empirical models or observations. The model results have relatively large deviations near sunrise time and sunset time and at the low altitudes. These results give us a reference to improve the model and enhance its performance in the future.

  20. Interstellar dust modelling: Interfacing laboratory, theoretical and observational studies (The THEMIS model)

    CERN Document Server

    Jones, Ant

    2015-01-01

    The construction of viable and physically-realistic interstellar dust models is only possible if the constraints imposed by laboratory data on interstellar dust analogue materials are respected and used within a meaningful theoretical framework. These physical dust models can then be directly compared to observations without the need for any tuning to fit the observations. Such models will generally fail to achieve the excellent fits to observations that empirical models are able to achieve. However, the physically-realistic approach will necessarily lead to a deeper insight and a fuller understanding of the nature and evolution of interstellar dust. The THEMIS modelling approach, based on (hydrogenated) amorphous carbons and amorphous silicates with metallic Fe and/or FeS nano-inclusions appears to be a promising move in this direction.

  1. Understanding atmospheric peroxyformic acid chemistry: observation, modeling and implication

    Directory of Open Access Journals (Sweden)

    H. Liang

    2015-01-01

    Full Text Available The existence and importance of peroxyformic acid (PFA in the atmosphere has been under controversy. We present here, for the first time, the observation data for PFA from four field measurements carried out in China. These data provided powerful evidence that PFA can stay in the atmosphere, typically in dozens of pptv level. The relationship between PFA and other detected peroxides was examined. The results showed that PFA had a strong positive correlation with its homolog, peroxyacetic acid, due to their similar sources and sinks. Through an evaluation of PFA production and removal rates, we proposed that the reactions between peroxyformyl radical (HC(OO2 and formaldehyde or the hydroperoxyl radical (HO2 were likely to be the major source and degradation into formic acid (FA was likely to be the major sink for PFA. Based on a box model evaluation, we proposed that the HC(OO2 and PFA chemistry was a major source for FA under low NOx conditions. Furthermore, it is found that the impact of the HC(OO2 and PFA chemistry on radical cycling was dependent on the yield of HC(OO2 radical from HC(O + O2 reaction. When this yield exceeded 50%, the HC(OO2 and PFA chemistry should not be neglected for calculating the radical budget. To make clear the exact importance of HC(OO2 and PFA chemistry in the atmosphere, further kinetic, field and modeling studies are required.

  2. Model of load distribution for earth observation satellite

    Science.gov (United States)

    Tu, Shumin; Du, Min; Li, Wei

    2017-03-01

    For the system of multiple types of EOS (Earth Observing Satellites), it is a vital issue to assure that each type of payloads carried by the group of EOS can be used efficiently and reasonably for in astronautics fields. Currently, most of researches on configuration of satellite and payloads focus on the scheduling for launched satellites. However, the assignments of payloads for un-launched satellites are bit researched, which are the same crucial as the scheduling of tasks. Moreover, the current models of satellite resources scheduling lack of more general characteristics. Referring the idea about roles-based access control (RBAC) of information system, this paper brings forward a model based on role-mining of RBAC to improve the generality and foresight of the method of assignments of satellite-payload. By this way, the assignment of satellite-payload can be mapped onto the problem of role-mining. A novel method will be introduced, based on the idea of biclique-combination in graph theory and evolutionary algorithm in intelligence computing, to address the role-mining problem of satellite-payload assignments. The simulation experiments are performed to verify the novel method. Finally, the work of this paper is concluded.

  3. The near-global mesospheric potassium layer: Observations and modeling

    Science.gov (United States)

    Dawkins, E. C. M.; Plane, J. M. C.; Chipperfield, M. P.; Feng, W.

    2015-08-01

    The meteoric metal layers act as unique tracers of chemistry and dynamics in the upper atmosphere. Existing lidar studies from a few locations show that K exhibits a semiannual seasonality (winter and summer maxima), quite unlike the annual seasonality (winter maximum and summer minimum) seen with Na and Fe. This work uses spaceborne observations made with the Optical Spectrograph and InfraRed Imager System instrument on the Odin satellite to retrieve the near-global K layer for the first time. The satellite data (2004 to mid-2013) are used to validate the implementation of a recently proposed potassium chemistry scheme in a whole atmosphere chemistry climate model, which provides a chemical basis for this semiannual seasonal behavior. The satellite and model data show that this semiannual seasonality is near global in extent, with the strongest variation at middle and high latitudes. The column abundance, centroid layer height, and root-mean-square width of the K layer are consistent with the limited available lidar record. The K data set is then used to investigate the impact of polar mesospheric clouds on the metal layers at high latitudes during summer. Finally, the occurrence frequency of sporadic K layers and their possible link to sporadic E layers are examined.

  4. The near‐global mesospheric potassium layer: Observations and modeling

    Science.gov (United States)

    Dawkins, E. C. M.; Chipperfield, M. P.; Feng, W.

    2015-01-01

    Abstract The meteoric metal layers act as unique tracers of chemistry and dynamics in the upper atmosphere. Existing lidar studies from a few locations show that K exhibits a semiannual seasonality (winter and summer maxima), quite unlike the annual seasonality (winter maximum and summer minimum) seen with Na and Fe. This work uses spaceborne observations made with the Optical Spectrograph and InfraRed Imager System instrument on the Odin satellite to retrieve the near‐global K layer for the first time. The satellite data (2004 to mid‐2013) are used to validate the implementation of a recently proposed potassium chemistry scheme in a whole atmosphere chemistry climate model, which provides a chemical basis for this semiannual seasonal behavior. The satellite and model data show that this semiannual seasonality is near global in extent, with the strongest variation at middle and high latitudes. The column abundance, centroid layer height, and root‐mean‐square width of the K layer are consistent with the limited available lidar record. The K data set is then used to investigate the impact of polar mesospheric clouds on the metal layers at high latitudes during summer. Finally, the occurrence frequency of sporadic K layers and their possible link to sporadic E layers are examined. PMID:27478716

  5. Tropical widening in models, reanalyses, and satellite observations

    Science.gov (United States)

    Davis, S. M.; Rosenlof, K. H.; Young, P. J.

    2012-12-01

    Poleward migration of the latitudinal edge of the tropics of ~0.25 - 3° decade-1 has been reported in several recent studies based on satellite, radiosonde, and reanalysis data covering the past ~30 years. Disagreements between models and observations have been noted, and to date, it has been unclear to what extent this large range of trends can be explained by the use of different data sources, time periods, and edge definitions. In this presentation, we address these issues by applying a suite of tropical edge latitude diagnostics based on tropopause height, winds, precipitation/evaporation, and outgoing longwave radiation (OLR) to six reanalyses and four satellite data sets. These diagnostics include both previously used definitions and new definitions designed for more robust detection. The wide range of widening trends is shown to be primarily due to the use of different data sets and edge definitions, and only secondarily due to varying start/end dates. We also show that the large trends (> ~ 1° decade-1) previously reported in tropopause and OLR diagnostics are partially due to the use of subjective definitions based on absolute thresholds. Statistically significant Hadley cell expansion based on the mean meridional streamfunction of ~1.0° decade-1 is present in all but one reanalysis, whereas other diagnostics yield trends of -0.5 - 0.8° decade-1 that are mostly insignificant. These results are compared to coupled model trends calculated over both the 20th and 21st centuries.

  6. Infrared Observations Of Saturn's Rings : Azimuthal Variations And Thermal Modeling

    Science.gov (United States)

    Leyrat, C.; Spilker, L. J.; Altobelli, N.; Pilorz, S.; Ferrari, C.; Edgington, S. G.; Wallis, B. D.; Nugent, C.; Flasar, M.

    2007-12-01

    Saturn's rings represent a collection of icy centimeter to meter size particles with their local dynamic dictated by self gravity, mutual collisions, surface roughness and thickness of the rings themselves. The infrared observations obtained by the CIRS infrared spectrometer on board Cassini over the last 3.5 year contain informations on the local dynamic, as the thermal signature of planetary rings is influenced both by the ring structure and the particle properties. The ring temperature is very dependent on the solar phase angle (Spilker et al., this issue), and on the local hour angle around Saturn, depending on whether or not particles' visible hemispheres are heated by the Sun. The geometric filling factor, which can be estimated from CIRS spectra, is less dependent on the local hour angle, suggesting that the non isothermal behavior of particles' surfaces have low impact, but it is very dependent on the spacecraft elevation for the A and C rings. The ring small scale structure can be explored using CIRS data. Variations of the filling factor with the local hour angle relative to the spacecraft azimuth reveals self-gravity wakes. We derive morphological parameters of such wakes in both A and B rings assuming that wakes can be modeled either by regularly spaced bars with infinite or finite optical depth. Our results indicates that wakes in the A ring are almost flat, with a ratio height/width ≈ 0.44 ± 0.16 and with a pitch angle relative to the orbital motion direction of ≍ 27deg. This is consistent with UVIS (Colwell et al., 2006) and VIMS data (Hedman et al., 2007). Such models are more difficult to constrain in the B ring, but small variations of the filling factor indicate that the pitch angle decreases drastically in this ring. We also present a new thermal bar model to explain azimuthal variations of temperatures in the A ring. We compare results with previous ring thermal models of spherical particles. The Cassini/CIRS azimuthal scans data set is

  7. Impacts of continual and periodic disturbances on a Central Amazonian forest: lessons from a gap model for future model improvement

    Science.gov (United States)

    Holm, J. A.; Chambers, J. Q.; Collins, W.

    2013-12-01

    Uncertainties surrounding vegetation and carbon responses to increased disturbance rates associated with climate change remains a major global change issue for Amazon forests. To help quantify the impacts of increased disturbances on climate and the earth system, the fidelity of tree mortality and disturbance algorithms in global land surface models (here the Community Land Model, CLM) warrant critical evaluation. In order to address this issue, we parameterized and calibrated ZELIG-TROP, a dynamic vegetation gap model, to simulate a complex Central Amazon forest toward improving disturbance-recovery processes in CLM. To evaluate the long-term consequences of increased disturbance rates in ZELIG-TROP and CLM for a Central Amazon rainforest, we 1) doubled background tree mortality rates (i.e., high disturbance treatment), and 2) applied a periodic disturbance treatment of removing 20% of stems every 50 years (i.e., periodic treatment) and compared model results. For the high disturbance treatment, ZELIG-TROP predicted that AGB and ANPP decreased by an average of 110 Mg ha-1 and 0.48 Mg C ha-1 yr-1 respectively (41.9% and 7.7%). The net carbon loss due to the periodic treatment, with four large-scale disturbances, was not as extreme as the loss from the high disturbance treatment, due to recovery dynamics. AGB only decreased by 15.9% (vs. 41.9%), however ANPP decreased by 19% (vs. 7.7%). For the high disturbance treatment in ZELIG-TROP, there were a higher proportion of smaller stems and a decrease in larger stems. This resulted in a decrease in coarse litter (trunks and large branches >10 cm in diameter) production rates (Mg C ha-1 yr-1) by 11.5%. For the periodic disturbance the average coarse litter production rates increased by 11.2% due to the four large-scale disturbance events. A comparison of the biomass response of ZELIG-TROP and CLM from simulated disturbance and recovery events displayed the same pattern between the two models, and for both disturbance

  8. Air-Sea interactions:Observations and models

    Science.gov (United States)

    Clayson, C. A.

    2014-12-01

    these analyses between satellite data sets, reanalysis products, and CMIP5 models. By focusing to a large extent on distributional characteristics, and particularly to extremes, comparisons of in situ observations and satellite data sets with distributions from coupled models (e.g. CMIP5) can be made directly.

  9. Tidally modulated eruptions on Enceladus: Cassini ISS observations and models

    Energy Technology Data Exchange (ETDEWEB)

    Nimmo, Francis [Department of Earth and Planetary Sciences, University of California, Santa Cruz, CA 95064 (United States); Porco, Carolyn; Mitchell, Colin, E-mail: carolyn@ciclops.org [CICLOPS, Space Science Institute, Boulder, CO 80304 (United States)

    2014-09-01

    We use images acquired by the Cassini Imaging Science Subsystem (ISS) to investigate the temporal variation of the brightness and height of the south polar plume of Enceladus. The plume's brightness peaks around the moon's apoapse, but with no systematic variation in scale height with either plume brightness or Enceladus' orbital position. We compare our results, both alone and supplemented with Cassini near-infrared observations, with predictions obtained from models in which tidal stresses are the principal control of the eruptive behavior. There are three main ways of explaining the observations: (1) the activity is controlled by right-lateral strike slip motion; (2) the activity is driven by eccentricity tides with an apparent time delay of about 5 hr; (3) the activity is driven by eccentricity tides plus a 1:1 physical libration with an amplitude of about 0.°8 (3.5 km). The second hypothesis might imply either a delayed eruptive response, or a dissipative, viscoelastic interior. The third hypothesis requires a libration amplitude an order of magnitude larger than predicted for a solid Enceladus. While we cannot currently exclude any of these hypotheses, the third, which is plausible for an Enceladus with a subsurface ocean, is testable by using repeat imaging of the moon's surface. A dissipative interior suggests that a regional background heat source should be detectable. The lack of a systematic variation in plume scale height, despite the large variations in plume brightness, is plausibly the result of supersonic flow; the details of the eruption process are yet to be understood.

  10. Image quality in CT: From physical measurements to model observers.

    Science.gov (United States)

    Verdun, F R; Racine, D; Ott, J G; Tapiovaara, M J; Toroi, P; Bochud, F O; Veldkamp, W J H; Schegerer, A; Bouwman, R W; Giron, I Hernandez; Marshall, N W; Edyvean, S

    2015-12-01

    Evaluation of image quality (IQ) in Computed Tomography (CT) is important to ensure that diagnostic questions are correctly answered, whilst keeping radiation dose to the patient as low as is reasonably possible. The assessment of individual aspects of IQ is already a key component of routine quality control of medical x-ray devices. These values together with standard dose indicators can be used to give rise to 'figures of merit' (FOM) to characterise the dose efficiency of the CT scanners operating in certain modes. The demand for clinically relevant IQ characterisation has naturally increased with the development of CT technology (detectors efficiency, image reconstruction and processing), resulting in the adaptation and evolution of assessment methods. The purpose of this review is to present the spectrum of various methods that have been used to characterise image quality in CT: from objective measurements of physical parameters to clinically task-based approaches (i.e. model observer (MO) approach) including pure human observer approach. When combined together with a dose indicator, a generalised dose efficiency index can be explored in a framework of system and patient dose optimisation. We will focus on the IQ methodologies that are required for dealing with standard reconstruction, but also for iterative reconstruction algorithms. With this concept the previously used FOM will be presented with a proposal to update them in order to make them relevant and up to date with technological progress. The MO that objectively assesses IQ for clinically relevant tasks represents the most promising method in terms of radiologist sensitivity performance and therefore of most relevance in the clinical environment.

  11. Radiation Observations from CREAM & CREDO and Comparison with Standard Models

    Science.gov (United States)

    Dyer, C.; Watson, C.; Truscott, P.; Peerless, C.

    1996-12-01

    The Cosmic Radiation Environment and Activation Monitor (CREAM) has flown on six Shuttle flights between September 1991 and February 1995, covering the full range of inclinations as well as altitudes between 210 and 550 km. Meanwhile the Cosmic Radiation Environment and Dosimetry experiment (CREDO) has operated continuously on UOSAT-3 in 800 km, 98.7 degree orbit since April 1990. Similar detectors were launched on KITSAT-1 (1330 km, 66 degree inclination) in August 1992 and POSAT-l (790 km, 98.7 degree inclination) in September 1993. Since the summer of 1994, CREDO-II versions have been operating on APEX in an eccentric orbit (350x2486 km) at 70 degree inclination, and on STRV in geostationary transfer orbit (298x35953 km, 7 degree inclination). These experiments are designed to measure protons, cosmic rays and accumulated dose. Through the variety of missions employed they have now achieved wide coverage of the magnetosphere as well as a significant portion of a solar cycle. The LEO observations have shown the Westward drift of the South Atlantic Anomaly, new regimes of trapped protons in the region of L=2.6 following solar flare events in March 1991 and October 1992, and an altitude dependence of trapped protons which is at variance with AP8. On STRV the background channel of the Cold Ion Detector serves as a complementary electron detector and shows the extreme time variability of the outer radiation belt, while the total dose is significantly less than AE8 predictions. In addition to the data on trapped radiation, important results are being obtained on the linear energy transfer spectra from cosmic rays. Detailed shielding models of the APEX and STRV spacecraft have been constructed and used to compare the observations of dose and LET spectra with predictions from AE8, AP8 and CREME for a variety of shielding depths. Consistent results on the LET spectra are obtained from APEX and STRV when data are selected by cut-off rigidity. The influence of spacecraft

  12. The Effects of a Computer-Assisted Teaching Material, Designed According to the ASSURE Instructional Design and the ARCS Model of Motivation, on Students' Achievement Levels in a Mathematics Lesson and Their Resulting Attitudes

    Science.gov (United States)

    Karakis, Hilal; Karamete, Aysen; Okçu, Aydin

    2016-01-01

    This study examined the effects that computer-assisted instruction had on students' attitudes toward a mathematics lesson and toward learning mathematics with computer-assisted instruction. The computer software we used was based on the ASSURE Instructional Systems Design and the ARCS Model of Motivation, and the software was designed to teach…

  13. Developing Conceptual Models of Biodegradation: Lessons Learned From a Long-Term Study of a Crude-Oil Contaminant Plume

    Science.gov (United States)

    Cozzarelli, I. M.; Esaid, H. I.; Bekins, B. A.; Eganhouse, R. P.; Baedecker, M.

    2002-05-01

    Assessment of natural attenuation as a remedial option requires understanding the long-term fate of contaminant compounds. The development of correct conceptual models of biodegradation requires observations at spatial and temporal scales appropriate for the reactions being measured. For example, the availability of electron acceptors such as solid-phase iron oxides may vary at the cm scale due to aquifer heterogeneities. Characterizing the distribution of these oxides may require small-scale measurements over time scales of tens of years in order to assess their impact on the fate of contaminants. The long-term study of natural attenuation of hydrocarbons in a contaminant plume near Bemidji, MN provides insight into how natural attenuation of hydrocarbons evolves over time. The sandy glacial-outwash aquifer at this USGS Toxic Substances Hydrology research site was contaminated by crude oil in 1979. During the 16 years that data have been collected the shape and extent of the contaminant plume changed as redox reactions, most notably iron reduction, progressed over time. Investigation of the controlling microbial reactions in this system required a systematic and multi-scaled approach. Early indications of plume shrinkage were observed over a time scale of a few years, based on observation well data. These changes were associated with iron reduction near the crude-oil source. The depletion of Fe (III) oxides near the contaminant source caused the dissolved iron concentrations to increase and spread downgradient at a rate of approximately 3 m/year. The zone of maximum benzene, toluene, ethylbenzene, and xylene (BTEX) concentrations has also spread within the anoxic plume. Subsequent analyses of sediment and water, collected at small-scale cm intervals from cores in the contaminant plume, provided insight into the evolution of redox zones at smaller scales. Contaminants, such as ortho-xylene, that appeared to be contained near the oil source based on the larger

  14. Eight Year Climatologies from Observational (AIRS) and Model (MERRA) Data

    Science.gov (United States)

    Hearty, Thomas; Savtchenko, Andrey; Won, Young-In; Theobalk, Mike; Vollmer, Bruce; Manning, Evan; Smith, Peter; Ostrenga, Dana; Leptoukh, Greg

    2010-01-01

    We examine climatologies derived from eight years of temperature, water vapor, cloud, and trace gas observations made by the Atmospheric Infrared Sounder (AIRS) instrument flying on the Aqua satellite and compare them to similar climatologies constructed with data from a global assimilation model, the Modern Era Retrospective-Analysis for Research and Applications (MERRA). We use the AIRS climatologies to examine anomalies and trends in the AIRS data record. Since sampling can be an issue for infrared satellites in low earth orbit, we also use the MERRA data to examine the AIRS sampling biases. By sampling the MERRA data at the AIRS space-time locations both with and without the AIRS quality control we estimate the sampling bias of the AIRS climatology and the atmospheric conditions where AIRS has a lower sampling rate. While the AIRS temperature and water vapor sampling biases are small at low latitudes, they can be more than a few degrees in temperature or 10 percent in water vapor at higher latitudes. The largest sampling biases are over desert. The AIRS and MERRA data are available from the Goddard Earth Sciences Data and Information Services Center (GES DISC). The AIRS climatologies we used are available for analysis with the GIOVANNI data exploration tool. (see, http://disc.gsfc.nasa.gov).

  15. Model-observer similarity, error modeling and social learning in rhesus macaques.

    Science.gov (United States)

    Monfardini, Elisabetta; Hadj-Bouziane, Fadila; Meunier, Martine

    2014-01-01

    Monkeys readily learn to discriminate between rewarded and unrewarded items or actions by observing their conspecifics. However, they do not systematically learn from humans. Understanding what makes human-to-monkey transmission of knowledge work or fail could help identify mediators and moderators of social learning that operate regardless of language or culture, and transcend inter-species differences. Do monkeys fail to learn when human models show a behavior too dissimilar from the animals' own, or when they show a faultless performance devoid of error? To address this question, six rhesus macaques trained to find which object within a pair concealed a food reward were successively tested with three models: a familiar conspecific, a 'stimulus-enhancing' human actively drawing the animal's attention to one object of the pair without actually performing the task, and a 'monkey-like' human performing the task in the same way as the monkey model did. Reward was manipulated to ensure that all models showed equal proportions of errors and successes. The 'monkey-like' human model improved the animals' subsequent object discrimination learning as much as a conspecific did, whereas the 'stimulus-enhancing' human model tended on the contrary to retard learning. Modeling errors rather than successes optimized learning from the monkey and 'monkey-like' models, while exacerbating the adverse effect of the 'stimulus-enhancing' model. These findings identify error modeling as a moderator of social learning in monkeys that amplifies the models' influence, whether beneficial or detrimental. By contrast, model-observer similarity in behavior emerged as a mediator of social learning, that is, a prerequisite for a model to work in the first place. The latter finding suggests that, as preverbal infants, macaques need to perceive the model as 'like-me' and that, once this condition is fulfilled, any agent can become an effective model.

  16. Observations

    DEFF Research Database (Denmark)

    Rossiter, John R.; Percy, Larry

    2013-01-01

    as requiring a new model of how advertising communicates and persuades, which, as the authors' textbooks explain, is sheer nonsense and contrary to the goal of integrated marketing. We provide in this article a translation of practitioners' jargon into more scientifically acceptable terminology as well...... product or service or to achieve a higher price that consumers are willing to pay than would obtain in the absence of advertising. What has changed in recent years is the notable worsening of the academic-practitioner divide, which has seen academic advertising researchers pursuing increasingly...... unrealistic laboratory studies, textbook writers continuing to ignore practitioners' research appearing in trade publications and practitioner-oriented journals, and practitioners peeling off into high-sounding but meaningless jargon. also evident is the tendency to regard the new electronic media...

  17. Lessons Learned from Assimilating Altimeter Data into a Coupled General Circulation Model with the GMAO Augmented Ensemble Kalman Filter

    Science.gov (United States)

    Keppenne, Christian; Vernieres, Guillaume; Rienecker, Michele; Jacob, Jossy; Kovach, Robin

    2011-01-01

    Satellite altimetry measurements have provided global, evenly distributed observations of the ocean surface since 1993. However, the difficulties introduced by the presence of model biases and the requirement that data assimilation systems extrapolate the sea surface height (SSH) information to the subsurface in order to estimate the temperature, salinity and currents make it difficult to optimally exploit these measurements. This talk investigates the potential of the altimetry data assimilation once the biases are accounted for with an ad hoc bias estimation scheme. Either steady-state or state-dependent multivariate background-error covariances from an ensemble of model integrations are used to address the problem of extrapolating the information to the sub-surface. The GMAO ocean data assimilation system applied to an ensemble of coupled model instances using the GEOS-5 AGCM coupled to MOM4 is used in the investigation. To model the background error covariances, the system relies on a hybrid ensemble approach in which a small number of dynamically evolved model trajectories is augmented on the one hand with past instances of the state vector along each trajectory and, on the other, with a steady state ensemble of error estimates from a time series of short-term model forecasts. A state-dependent adaptive error-covariance localization and inflation algorithm controls how the SSH information is extrapolated to the sub-surface. A two-step predictor corrector approach is used to assimilate future information. Independent (not-assimilated) temperature and salinity observations from Argo floats are used to validate the assimilation. A two-step projection method in which the system first calculates a SSH increment and then projects this increment vertically onto the temperature, salt and current fields is found to be most effective in reconstructing the sub-surface information. The performance of the system in reconstructing the sub-surface fields is particularly

  18. NASA Engineering Network Lessons Learned

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA Lessons Learned system provides access to official, reviewed lessons learned from NASA programs and projects. These lessons have been made available to the...

  19. Establishing a new model of integrated primary and secondary care based around general practice: a case study of lessons learned and challenges.

    Science.gov (United States)

    Jackson, Claire L; Donald, Maria; Russell, Anthony W; McIntyre, H David

    2017-05-09

    This case study describes the development and implementation of an innovative integrated primary-secondary model of care for people with complex diabetes. The aim of the paper is to present the experiences of clinicians and researchers involved in implementing the 'Beacon' model by providing a discussion of the contextual factors, including lessons learned, challenges and solutions. Beacon-type models of community care for people with chronic disease are well placed to deliver on Australia's health care reform agenda, and this commentary provides rich contextual information relevant to the translation of such models into policy and practice.What is known about the topic? Better integrated clinical models of care with close cooperation between hospital-based specialists and general practitioners (GPs) is fundamental to chronic disease management.What does this paper add? A real world example of the challenges faced in implementing models of integrated care across diverse settings and business models.What are the implications for clinicians? Practice, organisational and external factors including energy clinician leadership and resourcing are critical for translation of evidence into ongoing practice.

  20. Observing the observer (I): meta-bayesian models of learning and decision-making.

    NARCIS (Netherlands)

    Daunizeau, J.; Ouden, H.E.M. den; Pessiglione, M.; Kiebel, S.J.; Stephan, K.E.; Friston, K.J.

    2010-01-01

    In this paper, we present a generic approach that can be used to infer how subjects make optimal decisions under uncertainty. This approach induces a distinction between a subject's perceptual model, which underlies the representation of a hidden "state of affairs" and a response model, which predic

  1. Inflation in string theory confronts data/Les mod\\`eles d'inflation en th\\'eorie des cordes face aux observations

    CERN Document Server

    Silverstein, Eva

    2015-01-01

    Following the 2015 Planck release, we briefly comment on the status and some ongoing opportunities in the interface between inflationary cosmology, string theory, and CMB data. The constraints in the $r$-$n_s$ plane introduce a new parameter into inflationary cosmology relative to the simplest quadratic inflation model, in a direction which fits well with couplings to heavy fields as occurs in string theory. The precision of the data permits further searches for and constraints on additional model-dependent features, such as oscillatory $N$-spectra, a program requiring specific theoretically motivated shapes. Since the perturbations can easily be affected by additional sectors and couplings, null results can usefully bound such contributions. We also review the broader lessons string theory has contributed to our understanding of primordial inflation, and close with some approaches to a more complete framework. Published in a special volume of Comptes Rendus on Inflation: Theoretical and Observational Status.

  2. Increasing self-efficacy and quality lesson planning using Lesson-Study with elementary preservice teachers

    Science.gov (United States)

    Mitchell, Elizabeth Ann

    This qualitative, quasi-experimental study examined if lesson-study could be a successful approach in improving lesson plan quality and increasing self-efficacy levels toward teaching science at the preservice elementary teacher level in North Mississippi. Lesson-Study can be defined as a cycle of instructional improvement in which small groups work together to design and teach a lesson, revising again as needed over the course of a semester. This study described the experiences of two sections of preservice teachers enrolled in a science methods course as they engaged in lesson-study at a comprehensive university in Northeast Mississippi. One section of the class served as the control group while the other section, as the treatment group, received lesson-study over the course of the semester. Data was gathered in the form of interviews, observations, and a self-efficacy survey (STEBI-B). Lesson plans were also graded using a rubric to determine quality level. Findings indicated that, while not statistically significant, the treatment groups scores on the self-efficacy instrument increased more on average than the control groups' scores. There were also positive comments about the lesson study process from the teacher candidates in the treatment group as well as positive behaviors recorded by the researcher. Additionally, according to the external evaluators who graded the final drafts of the lessons, the treatment group had greater gains than the control class on average. These conclusions suggested the lesson study process implemented during the preservice teaching level can be beneficial.

  3. Observational constraints on inflation models with nonminimal scalar field

    CERN Document Server

    Noh, H

    2001-01-01

    We present the power spectra of the scalar- and tensor-type structures generated in an inflation model based on the nonminimally coupled scalar field with a self coupling. By comparing the contributions of these structures to the anisotropy of the cosmic microwave background radiation with the four year COBE DMR data we derive strong constraints on model parameters and the inflation model.

  4. Spectropolarimetry of stripped-envelope supernovae: observations and modelling

    Science.gov (United States)

    Tanaka, Masaomi

    2017-09-01

    Spectropolarimetry is one of the most powerful methods to study the multi-dimensional geometry of supernovae (SNe). We present a brief summary of the spectropolarimetric observations of stripped-envelope core-collapse SNe. Observations indicate that stripped-envelope SNe generally have a non-axisymmetric ion distribution in the ejecta. Three-dimensional clumpy geometry nicely explains the observed properties. A typical size of the clumps deduced from observations is relatively large: http://www.w3.org/1999/xlink" xlink:href="RSTA20160273IM1"/>25% of the photosphere. Such a large-scale clumpy structure is similar to that observed in Cassiopeia A, and suggests that large-scale convection or standing accretion shock instability takes place at the onset of the explosion. This article is part of the themed issue 'Bridging the gap: from massive stars to supernovae'.

  5. Lesson "Balance in Nature

    Science.gov (United States)

    Chapanova, V.

    2012-04-01

    Lesson "Balance in Nature" This simulation game-lesson (Balance in Nature) gives an opportunity for the students to show creativity, work independently, and to create models and ideas. It creates future-oriented thought connected to their experience, allowing them to propose solutions for global problems and personal responsibility for their activities. The class is divided in two teams. Each team chooses questions. 1. Question: Pollution in the environment. 2. Question: Care for nature and climate. The teams work on the chosen tasks. They make drafts, notes and formulate their solutions on small pieces of paper, explaining the impact on nature and society. They express their points of view using many different opinions. This generates alternative thoughts and results in creative solutions. With the new knowledge and positive behaviour defined, everybody realizes that they can do something positive towards nature and climate problems and the importance of individuals for solving global problems is evident. Our main goal is to recover the ecological balance, and everybody explains his or her own well-grounded opinions. In this work process the students obtain knowledge, skills and more responsible behaviour. This process, based on his or her own experience, dialogue and teamwork, helps the participant's self-development. Making the model "human↔ nature" expresses how human activities impact the natural Earth and how these impacts in turn affect society. Taking personal responsibility, we can reduce global warming and help the Earth. By helping nature we help ourselves. Teacher: Veselina Boycheva-Chapanova " Saint Patriarch Evtimii" Scholl Str. "Ivan Vazov"-19 Plovdiv Bulgaria

  6. Design, Implementation, and Lessons Learned from a Digital Storytelling Project in an Undergraduate Health Promotion Theory Course

    Science.gov (United States)

    Rimando, Marylen; Smalley, K. Bryant; Warren, Jacob C.

    2015-01-01

    This article describes the design, implementation and lessons learned from a digital storytelling project in a health promotion theory course. From 2011-2012, 195 health promotion majors completed a digital storytelling project at a Midwestern university. The instructor observed students' understanding of theories and models. This article adds to…

  7. Alternative methods for specification of observed forcing in single-column models and cloud system models

    Science.gov (United States)

    Randall, David A.; Cripe, Douglas G.

    1999-10-01

    We discuss alternative methods for prescribing advective tendencies in single-column models (SCMs) and cloud system models. These include "revealed forcing," in which the total advective tendency is prescribed from observations; "horizontal advective forcing," in which the horizontal advective tendencies are prescribed, together with the observed vertical motion which is combined with the predicted sounding to determine the tendencies due to vertical advection; and "relaxation forcing," in which the horizontal advective tendencies are computed by relaxing the sounding toward the observed upstream sounding, with a relaxation timescale determined by the time required for the wind to carry parcels across the grid column. When relaxation forcing is used, the horizontal advective tendencies can be diagnosed from the model output and compared with the corresponding observed tendencies. We present SCM results to illustrate these three forcing methods, based on data from several field experiments in both the tropics and the midlatitudes. Each method is shown to have its strengths and weaknesses. Overall, the results presented here do not show unambiguous differences between revealed forcing and horizontal advective forcing. The two methods appear to be generally comparable. Revealed forcing may therefore be preferred for its simplicity. Relaxation forcing guarantees realistic soundings of the state variables but can produce large errors in parameterized processes which are driven by rates (e.g., fluxes) rather than states. In particular, relaxation forcing gives large errors in the precipitation rate in this model. We demonstrate that relaxation forcing leads to unrealistically high (low) precipitation in versions of the model which tend to produce unrealistically dry (humid) soundings. The observed horizontal advective tendencies in the tropics are so weak, especially for temperature, that small absolute errors in the diabatic tendencies diagnosed with relaxation forcing

  8. Modelling Solar Oscillation Power Spectra: II. Parametric Model of Spectral Lines Observed in Doppler Velocity Measurements

    CERN Document Server

    Vorontsov, Sergei V

    2013-01-01

    We describe a global parametric model for the observed power spectra of solar oscillations of intermediate and low degree. A physically motivated parameterization is used as a substitute for a direct description of mode excitation and damping as these mechanisms remain poorly understood. The model is targeted at the accurate fitting of power spectra coming from Doppler velocity measurements and uses an adaptive response function that accounts for both the vertical and horizontal components of the velocity field on the solar surface and for possible instrumental and observational distortions. The model is continuous in frequency, can easily be adapted to intensity measurements and extends naturally to the analysis of high-frequency pseudo modes (interference peaks at frequencies above the atmospheric acoustic cutoff).

  9. Analysis of the 2014 “APEC Blue” in Beijing Using More than One Decade of Satellite Observations: Lessons Learned from Radical Emission Control Measures

    Directory of Open Access Journals (Sweden)

    Ran Meng

    2015-11-01

    Full Text Available During the 2014 Asia-Pacific Economic Cooperation (APEC Economic Leaders’ Meetings in Beijing, the Chinese government made significant efforts to clear Beijing’s sky. The emission control measures were very effective and the improved air quality during the APEC Meetings was called the “APEC Blue”. To monitor and estimate how these emission control measures affected air quality in Beijing and its five neighboring large cities (Tianjin, Shijiazhuang, Tangshan, Jinan, and Qingdao, we compared and analyzed the satellite-retrieved Aerosol Optical Thickness (AOT products of the pre-APEC (18–31 October, APEC (1–11 November, and post-APEC periods (11–31 November in 2002–2014 and daily PM2.5 measurements of the three periods in 2014 on the ground. Compared with the pre- and post-APEC periods, both ground and satellite observations indicated significantly reduced aerosol loading during the 2014 APEC period in Beijing and its surroundings, but with apparent spatial heterogeneity. For example, the peak value of PM2.5 in Beijing were around 100 µg∙m−3 during the APEC period, however, during the pre- and post-APEC periods, the peak values were up to 290 µg∙m−3. The following temporal correlation analysis of mean AOT values between Beijing and other five cities for the past thirteen years (2002–2014 indicated that the potential emission source regions strongly impacting air quality of Beijing were confined within central and southern Hebei as well as northern and southwestern Shandong, in correspondence with the spatial pattern of Digital Earth Model (DEM of the study region. In addition to stringent emission control measures, back trajectory analysis indicated that the relatively favorable regional transport pattern might also have contributed to the “APEC Blue” in Beijing. These results suggest that the “APEC Blue” is a temporarily regional phenomenon; a long-term improvement of air quality in Beijing is still challenging

  10. Do Students Really Understand Topology in the Lesson? A Case Study

    Science.gov (United States)

    Narli, Serkan

    2010-01-01

    This study aims to specify to what extent students understand topology during the lesson and to determine possible misconceptions. 14 teacher trainees registered at Secondary School Mathematics education department were observed in the topology lessons throughout a semester and data collected at the first topology lesson is presented here.…

  11. Modeling a thick unsaturated zone at San Gorgonio Pass, California: lessons learned after five years of artificial recharge

    Science.gov (United States)

    Flint, Alan L.; Ellett, Kevin M.; Christensen, Allen H.; Martin, Peter

    2012-01-01

    The information flow among the tasks of framework assessment, numerical modeling, model forecasting and hind casting, and system-performance monitoring is illustrated. Results provide an understanding of artificial recharge in high-altitude desert settings where large vertical distances may separate application ponds from their target aquifers. Approximately 3.8 million cubic meters of surface water was applied to spreading ponds from 2003–2007 to artificially recharge the underlying aquifer through a 200-meter thick unsaturated zone in the San Gorgonio Pass area in southern California. A study was conducted between 1997 and 2003, and a numerical model was developed to help determine the suitability of the site for artificial recharge. Ongoing monitoring results indicated that the existing model needed to be modified and recalibrated to more accurately predict artificial recharge at the site. The objective of this work was to recalibrate the model by using observation of the application rates, the rise and fall of the water level above a perching layer, and the approximate arrival time to the water table during the 5-yr monitoring period following initiation of long-term artificial recharge. Continuous monitoring of soil-matric potential, temperature, and water levels beneath the site indicated that artificial recharge reached the underlying water table between 3.75 and 4.5 yr after the initial application of the recharge water. The model was modified to allow the simulation to more adequately match the perching layer dynamics and the time of arrival at the water table. The instrumentation also showed that the lag time between changes in application of water at the surface and the response at the perching layer decreased from about 4 mo to less than 1 mo due to the wet-up of the unsaturated zone and the increase in relative permeability. The results of this study demonstrate the importance of iteratively monitoring and modeling the unsaturated zone in layered

  12. Air chemistry over the Dead Sea: Observations and Model Simulations

    Science.gov (United States)

    Luria, M.; Tas, E.; Obrist, D.; Marveev, V.; Peleg, M.

    2011-12-01

    the warm Dead Sea boundary layer. The efficient oxidation of gaseous elemental mercury (GEM) under temperate conditions by RBS was unexpected considering the fact that the dissociation reaction of HgBr, is more than 2.5 orders of magnitude higher under Dead Sea temperatures as compared with the Polar air, where ADMEs were previously reported. Model simulations suggested that at this site BrO, rather than Br is the dominant oxidant. The best agreement between simulations and observations was achieved by applying rate constants for kHg+Br and kHg+BrO, of 2.7x10-13 cm3molecule-1s-1 and 1.5x10-13 cm3molecule-1s-1, respectively, indicating that kHg+BrO is higher than most previously reported values and that BrO is a more efficient oxidant than Br in an ozone-rich atmosphere (i.e., for [BrO]/[Br] > 2).

  13. Modeling Seven Years of Event Horizon Telescope Observations with Radiatively Inefficient Accretion Flow Models

    CERN Document Server

    Broderick, Avery E; Johnson, Michael D; Rosenfeld, Katherine; Wang, Carlos; Doeleman, Sheperd S; Akiyama, Kazunori; Johannsen, Tim; Roy, Alan L

    2016-01-01

    An initial three-station version of the Event Horizon Telescope, a millimeter-wavelength very-long baseline interferometer, has observed Sagittarius A* (Sgr A*) repeatedly from 2007 to 2013, resulting in the measurement of a variety of interferometric quantities. Of particular importance, there is now a large set of closure phases, measured over a number of independent observing epochs. We analyze these observations within the context of a realization of semi-analytic radiatively inefficient disk models, implicated by the low luminosity of Sgr A*. We find a broad consistency among the various observing epochs and between different interferometric data types, with the latter providing significant support for this class of models of Sgr A*. The new data significantly tighten existing constraints on the spin magnitude and its orientation within this model context, finding a spin magnitude of $a=0.10^{+0.30+0.56}_{-0.10-0.10}$, an inclination with respect to the line of sight of $\\theta={60^\\circ}^{+5^\\circ+10^\\c...

  14. Japanese Lesson Study Sustaining Teacher Learning in the Classroom Context

    Science.gov (United States)

    Loose, Crystal Corle

    2014-01-01

    The purposes of this action research study were first to explore teacher perceptions of Japanese lesson study as a method of professional development, and second to take teachers through an action research process as they observed the implementation of a literacy lesson in the classroom. Situated Learning Theory, particularly related to teacher…

  15. Implementing Japanese Lesson Study in Foreign Countries: Misconceptions Revealed

    Science.gov (United States)

    Fujii, Toshiakira

    2014-01-01

    This paper is based on data gathered during visits to Uganda and Malawi, conducted by the International Math-teacher Professionalization Using Lesson Study (IMPULS) project and the Japanese International Cooperation Agency (JICA). The author's observations and experiences highlighted misconceptions about lesson study. The paper concludes that some…

  16. Estimation in partial linear EV models with replicated observations

    Institute of Scientific and Technical Information of China (English)

    CUI; Hengjian

    2004-01-01

    The aim of this work is to construct the parameter estimators in the partial linear errors-in-variables (EV) models and explore their asymptotic properties. Unlike other related References, the assumption of known error covariance matrix is removed when the sample can be repeatedly drawn at each designed point from the model. The estimators of interested regression parameters, and the model error variance, as well as the nonparametric function, are constructed. Under some regular conditions, all of the estimators prove strongly consistent. Meanwhile, the asymptotic normality for the estimator of regression parameter is also presented. A simulation study is reported to illustrate our asymptotic results.

  17. Inverse modeling of hydrologic parameters using surface flux and runoff observations in the Community Land Model

    Directory of Open Access Journals (Sweden)

    Y. Sun

    2013-04-01

    Full Text Available This study demonstrates the possibility of inverting hydrologic parameters using surface flux and runoff observations in version 4 of the Community Land Model (CLM4. Previous studies showed that surface flux and runoff calculations are sensitive to major hydrologic parameters in CLM4 over different watersheds, and illustrated the necessity and possibility of parameter calibration. Two inversion strategies, the deterministic least-square fitting and stochastic Markov-Chain Monte-Carlo (MCMC Bayesian inversion approaches, are evaluated by applying them to CLM4 at selected sites. The unknowns to be estimated include surface and subsurface runoff generation parameters and vadose zone soil water parameters. We find that using model parameters calibrated by the least-square fitting provides little improvements in the model simulations but the sampling-based stochastic inversion approaches are consistent – as more information comes in, the predictive intervals of the calibrated parameters become narrower and the misfits between the calculated and observed responses decrease. In general, parameters that are identified to be significant through sensitivity analyses and statistical tests are better calibrated than those with weak or nonlinear impacts on flux or runoff observations. Temporal resolution of observations has larger impacts on the results of inverse modeling using heat flux data than runoff data. Soil and vegetation cover have important impacts on parameter sensitivities, leading to different patterns of posterior distributions of parameters at different sites. Overall, the MCMC-Bayesian inversion approach effectively and reliably improves the simulation of CLM under different climates and environmental conditions. Bayesian model averaging of the posterior estimates with different reference acceptance probabilities can smooth the posterior distribution and provide more reliable parameter estimates, but at the expense of wider uncertainty

  18. Runoff modeling of the Mara River using Satellite Observed Soil ...

    African Journals Online (AJOL)

    with European Remote Sensing (ERS) Scatterometer in modeling runoff of the Zambezi river basin. ... (2008) using Geospatial Stream Flow ... obtained for Mara River at Mara mines, Nyangores at Bomet and Amala at Mulot river gauging ...

  19. Ben Franklin. [Lesson Plan].

    Science.gov (United States)

    Discovery Communications, Inc., Bethesda, MD.

    Based on Benjamin Franklin's "Poor Richard's Almanac," this lesson plan presents activities designed to help students understand that Ben Franklin is known, among other things, for his wit and wisdom; that Franklin published an almanac for 25 years; and he scattered aphorisms throughout the almanac. The main activity in the lesson is for students…

  20. "Walden". [Lesson Plan].

    Science.gov (United States)

    Surber, Gretchen C.

    Based on Henry David Thoreau's book "Walden," this lesson plan presents activities designed to help students understand that acquisitiveness and simplicity can be opposing life philosophies; and that both philosophies have had notable adherents. The main activity of the lesson involves students researching historical characters (including Thoreau)…

  1. "Frankenstein." [Lesson Plan].

    Science.gov (United States)

    Simon, Melanie

    Based on Mary Shelley's novel "Frankenstein," this lesson plan presents activities designed to help students understand that active readers interpret a novel (its characters, plot, setting, and theme) in different ways; and the great literature can be and has been adapted in many ways over time. The main activity of the lesson involves students…

  2. Soybean Production Lesson Plan.

    Science.gov (United States)

    Carlson, Keith R.

    These lesson plans for teaching soybean production in a secondary or postsecondary vocational agriculture class are organized in nine units and cover the following topics: raising soybeans, optimum tillage, fertilizer and lime, seed selection, pest management, planting, troubleshooting, double cropping, and harvesting. Each lesson plan contains…

  3. Great Expectations. [Lesson Plan].

    Science.gov (United States)

    Devine, Kelley

    Based on Charles Dickens' novel "Great Expectations," this lesson plan presents activities designed to help students understand the differences between totalitarianism and democracy; and a that a writer of a story considers theme, plot, characters, setting, and point of view. The main activity of the lesson involves students working in groups to…

  4. Don Quixote. [Lesson Plan].

    Science.gov (United States)

    Rooks, Kristen

    Based on Miguel de Cervantes' novel "Don Quixote," this lesson plan presents activities designed to help students understand that Quixote's misperceptions are understandable; writers often describe one object to sound as if it were something else; and metaphors help readers see with new eyes. The main activity of the lesson involves students…

  5. Gulliver's Travels. [Lesson Plan].

    Science.gov (United States)

    Rooks, Kirsten; McLean, Mary

    Based on Jonathan Swift's novel "Gulliver's Travels," this lesson plan presents activities designed to help students understand that Swift comments on undesirable outcomes of advances in science; and other authors have also warned against abuse of science. The main activity of the lesson involves students developing a poster illustrating views of…

  6. Automatic Dance Lesson Generation

    Science.gov (United States)

    Yang, Yang; Leung, H.; Yue, Lihua; Deng, LiQun

    2012-01-01

    In this paper, an automatic lesson generation system is presented which is suitable in a learning-by-mimicking scenario where the learning objects can be represented as multiattribute time series data. The dance is used as an example in this paper to illustrate the idea. Given a dance motion sequence as the input, the proposed lesson generation…

  7. Mini Lessons from FDA.

    Science.gov (United States)

    Food and Drug Administration (DHEW), Washington, DC.

    Eight self-contained lessons present information about topics of current interest in the Food and Drug Administration. Multidisciplinary in nature, the lessons can be integrated into ongoing activities in elementary or secondary level reading, math, language arts, social studies, science, art, health, consumer education, and home economics. The…

  8. A Lesson in Tolerance

    Science.gov (United States)

    Johnt, Marlene

    2004-01-01

    This article describes one classroom's experience integrating a three-part lesson that focused on tolerance. In the lesson, students examined works by American folk-art painter Edward Hicks, researched quotes about tolerance in society, and applied calligraphy skills to an original composition.

  9. Fish Facts. Lesson Plan.

    Science.gov (United States)

    Chan, Mike

    This lesson plan is designed for a 50-minute class to teach extension home economists and homemakers about buying, storing, and using fish. The lesson plan contains references, a list of equipment needed, objectives, and the presentation. The presentation consists of an outline of instruction coordinated with methods of instruction and aids and…

  10. Utilization of remote sensing observations in hydrologic models

    Science.gov (United States)

    Ragan, R. M.

    1977-01-01

    Most of the remote sensing related work in hydrologic modeling has centered on modifying existing models to take advantage of the capabilities of new sensor techniques. There has been enough success with this approach to insure that remote sensing is a powerful tool in modeling the watershed processes. Unfortunately, many of the models in use were designed without recognizing the growth of remote sensing technology. Thus, their parameters were selected to be map or field crew definable. It is believed that the real benefits will come through the evolution of new models having new parameters that are developed specifically to take advantage of our capabilities in remote sensing. The ability to define hydrologically active areas could have a significant impact. The ability to define soil moisture and the evolution of new techniques to estimate evoportransportation could significantly modify our approach to hydrologic modeling. Still, without a major educational effort to develop an understanding of the techniques used to extract parameter estimates from remote sensing data, the potential offered by this new technology will not be achieved.

  11. Intelligent Cognitive Radio Models for Enhancing Future Radio Astronomy Observations

    Directory of Open Access Journals (Sweden)

    Ayodele Abiola Periola

    2016-01-01

    Full Text Available Radio astronomy organisations desire to optimise the terrestrial radio astronomy observations by mitigating against interference and enhancing angular resolution. Ground telescopes (GTs experience interference from intersatellite links (ISLs. Astronomy source radio signals received by GTs are analysed at the high performance computing (HPC infrastructure. Furthermore, observation limitation conditions prevent GTs from conducting radio astronomy observations all the time, thereby causing low HPC utilisation. This paper proposes mechanisms that protect GTs from ISL interference without permanent prevention of ISL data transmission and enhance angular resolution. The ISL transmits data by taking advantage of similarities in the sequence of observed astronomy sources to increase ISL connection duration. In addition, the paper proposes a mechanism that enhances angular resolution by using reconfigurable earth stations. Furthermore, the paper presents the opportunistic computing scheme (OCS to enhance HPC utilisation. OCS enables the underutilised HPC to be used to train learning algorithms of a cognitive base station. The performances of the three mechanisms are evaluated. Simulations show that the proposed mechanisms protect GTs from ISL interference, enhance angular resolution, and improve HPC utilisation.

  12. Body and Surface Wave Modeling of Observed Seismic Events

    Science.gov (United States)

    1980-09-01

    period WSS (30,90) instrument at Golden, Colorado. Figure 2. Three component observation of the San Fernando earthquake recorded at ALQ, Nev Mexico ...Planet. tat., 13, 85-96. . . . . . -, .. _ . 101 Console, R. (1976). ?%ccanismo focal* del terremoto del Friuli del 6 Maggio 1976, Ann. di Geof., 9

  13. Radar observations and physical model of asteroid 6489 Golevka

    Science.gov (United States)

    Hudson, R.; Ostro, S.; Jurgens, R.; Rosema, K.; Giorgini, J.; Winkler, R.; Rose, R.; Choate, D.; Cormier, R.; Franck, C.; Frye, R.; Howard, D.; Kelley, D.; Littlefair, R.; Slade, M.; Benner, L.; Thomas, M.; Mitchell, D.; Chodas, P.; Yeomans, D.; Scheeres, D.; Palmer, P.; Zaitsev, A.; Koyama, Y.; Nakamura, A.

    2000-01-01

    We report 8510-MHz (3,5-cm) radar observations of the Earth crossing asteroid (ECA) 6489 Golevka (1991 JX) obtained between June 3 and June 15, 1995, at Goldstone, the Very Large Array and the Evpatoria (Ukraine) and Kashima (Japan) radio antennas.

  14. Observational Constraints on Models of Rapidly Evolving Luminous Stars

    Science.gov (United States)

    Rosenfield, Philip; Dalcanton, Julianne; Bressan, Alessandro; Girardi, Leo; Marigo, Paola; Angst Team

    2015-01-01

    Resolved stellar populations in galaxies are excellent laboratories for testing our understanding of galaxy formation, integrated colors and luminosities, supernova progenitor masses, and energy input from stellar feedback. However, the usefulness of resolved stellar populations rests on the ability to accurately model the evolution of the underlying stars. Part of my thesis work is focused on two uncertain phases of stellar evolution; the luminous core helium burning (HeB) phase and the thermally pulsating AGB (TP-AGB) phase. Dwarf galaxies, imaged as part of the ACS Nearby Galaxy Survey Treasury and its HST/NIR follow-up campaign, provide ideal testing grounds for new models because the galaxies span ~2 dex in metallicity, many have significant HeB populations (i.e, the HeB sequence is populated with stars with masses from ~2-15 Msun), and many contain large numbers of TP-AGB stars. I will present how I used ANGST to constrain low metallicity stellar evolution models with the Padova-Trieste Stellar Evolution Code (PARSEC; the recently updated Padova Stellar Evolution Library) and COLIBRI (a new tool for modeling TP-AGB stars). Specifically, I will show how increasing the strength of core overshooting with increasing mass in HeB stars improves data and model agreement. I will also present constraints to the mass loss prescriptions of low mass, low metallicity TP-AGB stars.

  15. How Does a Lesson Plan?

    Science.gov (United States)

    New York City Board of Education, Brooklyn, NY. Div. of Curriculum and Instruction.

    This manual for secondary school teachers offers sample lesson plans that may be used to guide and stimulate experimentation and development of creative instructional units. Lesson plan components are defined, and various types of lessons and their significant characteristics are identified. These characteristic types of lessons are illustrated,…

  16. Modeling of Protostellar Clouds and their Observational Properties

    CERN Document Server

    Zhilkin, A G; Zamozdra, S N

    2009-01-01

    A physical model and two-dimensional numerical method for computing the evolution and spectra of protostellar clouds are described. The physical model is based on a system of magneto-gasdynamical equations, including ohmic and ambipolar diffusion, and a scheme for calculating the thermal and ionization structure of a cloud. The dust and gas temperatures are determined during the calculations of the thermal structure of the cloud. The results of computing the dynamical and thermal structure of the cloud are used to model the radiative transfer in continuum and in molecular lines. We presented the results for clouds in hydrostatic and thermal equilibrium. The evolution of a rotating magnetic protostellar cloud starting from a quasi-static state is also considered. Spectral maps for optically thick lines of linear molecules are analyzed. We have shown that the influence of the magnetic field and rotation can lead to a redistribution of angular momentum in the cloud and the formation of a characteristic rotationa...

  17. Anisotropy in Fracking: A Percolation Model for Observed Microseismicity

    CERN Document Server

    Norris, J Quinn; Rundle, John B

    2014-01-01

    Hydraulic fracturing (fracking) using high pressures and a low viscosity fluid allow the extraction of large quantiles of oil and gas from very low permeability shale formations. The initial production of oil and gas at depth leads to high pressures and an extensive distribution of natural fractures which reduce the pressures. With time these fractures heal, sealing the remaining oil and gas in place. High volume fracking opens the healed fractures allowing the oil and gas to flow the horizontal productions wells. We model the injection process using invasion percolation. We utilize a 2D square lattice of bonds to model the sealed natural fractures. The bonds are assigned random strengths and the fluid, injected at a point, opens the weakest bond adjacent to the growing cluster of opened bonds. Our model exhibits burst dynamics in which the clusters extends rapidly into regions with weak bonds. We associate these bursts with the microseismic activity generated by fracking injections. A principal object of thi...

  18. Reconstructing parameters of spreading models from partial observations

    CERN Document Server

    Lokhov, Andrey Y

    2016-01-01

    Spreading processes are often modelled as a stochastic dynamics occurring on top of a given network with edge weights corresponding to the transmission probabilities. Knowledge of veracious transmission probabilities is essential for prediction, optimization, and control of diffusion dynamics. Unfortunately, in most cases the transmission rates are unknown and need to be reconstructed from the spreading data. Moreover, in realistic settings it is impossible to monitor the state of each node at every time, and thus the data is highly incomplete. We introduce an efficient dynamic message-passing algorithm, which is able to reconstruct parameters of the spreading model given only partial information on the activation times of nodes in the network. The method is generalizable to a large class of dynamic models, as well to the case of temporal graphs.

  19. The cosmological Janus model: comparison with observational data

    Science.gov (United States)

    Petit, Jean-Pierre; Dagostini, Gilles

    2017-01-01

    In 2014 we presented a model based on a system of two coupled field equations to describe two populations of particles, one positive and the other mass of negative mass. The analysis of this system by Newtonian approximation show that the masses of the same signs attract according to Newton's law while the masses of opposite signs repel according to an anti-Newton law. This eliminates the runaway phenomenon. It uses the time-dependent exact solution of this system to build the bolometric magnitude distribution of the red-shift. Comparing the prediction of our model -which requires adjustment with a single parameter- with the data from 740 supernovae highlighting the acceleration of the universe gives an excellent agreement. The comparison is then made with the multi-parametric Λ CDM model.

  20. Opportunities for Sex Education and Personal and Social Education (PSE) through Science Lessons: The Comments of Primary Pupils When Observing Meal Worms and Brine Shrimp.

    Science.gov (United States)

    Tunnicliffe, Sue Dale; Reiss, Michael J.

    1999-01-01

    Presents a characterization of students' comments during observation of meal worms or brine shrimp. Finds that many student comments had to do with sex, reproduction, death, violence, and the life history of the organisms. Significant differences in conversations occurred across age and gender groups. Contains 32 references. (Author/WRM)