Reflections on mirror neurons and speech perception

Science.gov (United States)

Lotto, Andrew J.; Hickok, Gregory S.; Holt, Lori L.

2010-01-01

The discovery of mirror neurons, a class of neurons that respond when a monkey performs an action and also when the monkey observes others producing the same action, has promoted a renaissance for the Motor Theory (MT) of speech perception. This is because mirror neurons seem to accomplish the same kind of one to one mapping between perception and action that MT theorizes to be the basis of human speech communication. However, this seeming correspondence is superficial, and there are theoretical and empirical reasons to temper enthusiasm about the explanatory role mirror neurons might have for speech perception. In fact, rather than providing support for MT, mirror neurons are actually inconsistent with the central tenets of MT. PMID:19223222

Identifying Pre-High School Students' Science Class Motivation Profiles to Increase Their Science Identification and Persistence

Science.gov (United States)

Chittum, Jessica R.; Jones, Brett D.

2017-01-01

One purpose of this study was to determine whether patterns existed in pre-high school students' motivation-related perceptions of their science classes. Another purpose was to examine the extent to which these patterns were related to their science identification, gender, grade level, class effort, and intentions to persist in science. We…

Secondary mirror system for the European Solar Telescope (EST)

Science.gov (United States)

Cavaller, L.; Siegel, B.; Prieto, G.; Hernandez, E.; Casalta, J. M.; Mercader, J.; Barriga, J.

2010-07-01

The European Solar Telescope (EST) is a European collaborative project to build a 4m class solar telescope in the Canary Islands, which is now in its design study phase. The telescope will provide diffraction limited performance for several instruments observing simultaneously at the Coudé focus at different wavelengths. A multi-conjugated adaptive optics system composed of a tip-tilt mirror and several deformable mirrors will be integrated in the telescope optical path. The secondary mirror system is composed of the mirror itself (Ø800mm), the alignment drives and the cooling system needed to remove the solar heat load from the mirror. During the design study the feasibility to provide fast tip-tilt capabilities at the secondary mirror to work as the adaptive optics tip-tilt mirror is also being evaluated.

Interpreting the relationships between single gender science classes and girls' academic motivation and interest

Science.gov (United States)

Johnson, Sonya L.

The purpose of this study was to determine how and to what extent single gender science classes affect motivation to learn scientific concepts, interest in science, and college major intent among high school and middle school girls. This study was designed to determine whether students' motivation to learn science changes when they are placed in a single gender science class. The study also measured whether the students' level of interest in science and desire to major in science changes based on their enrollment in a single gender class. Finally, the study investigated the career and college major intentions of the sample population used in the study. Girls in single gender groupings engage in more academic risk taking and participate more than girls in coeducational classes. This benefit alone responds to reform efforts and supports the abolition of gender-based obstacles. Single gender grouping could help encourage more girls to take interest in majoring in science, a field that is considered to be masculine. By increasing students' interest in science while enrolled in single gender classes, students may become more motivated to learn science. This study was conducted using seven, eighth, ninth and tenth grade girls from single sex and coeducational science classes. The students participated in 2 surveys, the Science Motivational Survey and the Test of Science Related Attitudes, at the beginning of the semester and at the end of the semester. In respect to girls in high school single gender science classes, results were contrary to recent studies that state that girls who received science education in a single gender setting have an increase in motivation and attitude towards science. The results did show that middle school girls in single gender science classes did show an increase in motivation.

Teaching Citizenship in Science Classes at the University of Arizona

Science.gov (United States)

Thompson, R. M.; Mangin, K.

2008-12-01

Science classes for non-science majors present unique opportunities to create lifelong science aficionados and teach citizenship skills. Because no specific content is needed for future courses, subject matter can be selected to maximize interest and assignments can be focused on life skills such as science literacy instead of discipline-specific content mastery. Dinosaurs! is a very successful non-major science class with a minimum enrollment of 150 that is intended for sophomores. One of the goals of this class is to increase students' awareness of social issues, the political process, and opportunities for keeping up with science later in life. The main theme of this class is evolution. The bird-dinosaur link is the perfect vehicle for illustrating the process of science because the lines of evidence are many, convincing, and based on discoveries made throughout the last half-century and continuing to the present day. The course is also about evolution the social issue. The second writing assignment is an in-class affective writing based on a newspaper article about the Dover, PA court case. The primary purpose of this assignment is to create a comfort zone for those students with strong ideological biases against evolution by allowing them to express their views without being judged, and to instill tolerance and understanding in students at the other end of the spectrum. Another homework uses thomas.loc.gov, the government's public website providing information about all legislation introduced since the 93rd Congress and much more. The assignment highlights the difficulty of passing legislation and the factors that contribute to a given bill's legislative success or failure using the Paleontological Resources Preservation Act, S320. Details of these assignments and others designed to achieve the goals stated above will be presented. A very different undergraduate program, Marine Discovery, offers science majors the opportunity to earn upper division science

Sciencey Girls: Discourses Supporting Working-Class Girls’ to Identify with Science

OpenAIRE

Spela Godec

2018-01-01

Women from working class and some ethnic minority backgrounds continue to be underrepresented in science, particularly in areas such as physical sciences and engineering. Many find it difficult to see science as something that is “for them”, which then has implications for their learning and participation in science. In this paper, I discuss findings from a U.K.-based qualitative study with 15 working-class girls, aged 11 to 13, from diverse ethnic backgrounds. Data were collected over the co...

Science education in a bilingual class: problematising a translational practice

Science.gov (United States)

Ünsal, Zeynep; Jakobson, Britt; Molander, Bengt-Olov; Wickman, Per-Olof

2016-10-01

In this article we examine how bilingual students construe relations between everyday language and the language of science. Studies concerning bilingual students language use in science class have mainly been conducted in settings where both the teacher and the students speak the same minority language. In this study data was collected in a class consisting of students aged 13-14. All students had Turkish as their minority language, whereas the teacher's minority language was Bosnian. The class was observed when they were working with acids and bases. In addition, the students were interviewed in groups. They were asked about how they use their languages during science lessons and then asked to describe and explain scientific phenomena and processes that had been a part of the observed lessons. For the analysis, practical epistemology analysis and the theory of translanguaging were used. The results show how the students' everyday language repertoire may limit their possibilities to make meaning of science. In particular, the teacher's practice of facilitating and supporting students' understanding of science content by relating it to concrete examples took another direction since the everyday words he used were not a part of the students' language repertoire. The study also shows how the students used their minority language as a resource to translate words from Swedish to Turkish in order to proceed with the science activities. However, translating scientific concepts was problematic and led to the students' descriptions of the concepts not being in line with how they are viewed in science. Finally, the study also demonstrates how monolingual exams may limit bilingual students' achievements in science. The study contributes by presenting and discussing circumstances that need to be taken into consideration when planning and conducting science lessons in classes where the teacher and the student do not share the same minority language.

Sciencey Girls: Discourses Supporting Working-Class Girls’ to Identify with Science

Directory of Open Access Journals (Sweden)

Spela Godec

2018-01-01

Full Text Available Women from working class and some ethnic minority backgrounds continue to be underrepresented in science, particularly in areas such as physical sciences and engineering. Many find it difficult to see science as something that is “for them”, which then has implications for their learning and participation in science. In this paper, I discuss findings from a U.K.-based qualitative study with 15 working-class girls, aged 11 to 13, from diverse ethnic backgrounds. Data were collected over the course of one academic year, through interviews and discussion groups with the girls and interviews with their science teachers, and analysed through a post-structural gender lens. The paper foregrounds five science-identifying girls, who negotiated their identification and engagement with science through the following discursive strategies: (i rendering gender invisible, (ii drawing attention to the presence of women in science, (iii reframing “science people” as caring and nurturing, and (iv cultural discourses of desirability of science. The findings contribute to the understanding of how working class girls—who are often “othered” and constructed as “unintelligible” within the dominant discursive regime of prototypical science—find identification with science possible. The paper discusses the affordances and challenges of each discursive strategy.

Teacher interpersonal behaviour and student attitudes in Brunei primary science classes classes

NARCIS (Netherlands)

Scott, R.; Brok, den P.J.; Fisher, D.; Staver, J.; Zandvliet, D.; Tillotson, J.; Anderson, C. W.; Crawley, F.

2004-01-01

This study investigated relationships between students’ perceptions of their teachers’ interpersonal behaviour and their subject-related attitude in primary science classes in Brunei. Teacher-student interpersonal behaviour was mapped with the Questionnaire on Teacher Interaction (QTI) and reported

Supporting Struggling Readers in Secondary School Science Classes

Science.gov (United States)

Roberts, Kelly D.; Takahashi, Kiriko; Park, Hye-Jin; Stodden, Robert A.

2012-01-01

Many secondary school students struggle to read complex expository text such as science textbooks. This article provides step-by-step guidance on how to foster expository reading for struggling readers in secondary school science classes. Two strategies are introduced: Text-to-Speech (TTS) Software as a reading compensatory strategy and the…

Science anxiety and social cognitive factors predicting STEM career aspirations of high school freshmen in general science class

Science.gov (United States)

Skells, Kristin Marie

Extant data was used to consider the association between science anxiety, social cognitive factors and STEM career aspirations of high school freshmen in general science classes. An adapted model based on social cognitive career theory (SCCT) was used to consider these relationships, with science anxiety functioning as a barrier in the model. The study assessed the following research questions: (1) Do social cognitive variables relate in the expected way to STEM career aspirations based on SCCT for ninth graders taking general science classes? (2) Is there an association between science anxiety and outcomes and processes identified in the SCCT model for ninth graders taking general science classes? (3) Does gender moderate these relationships? Results indicated that support was found for many of the central tenants of the SCCT model. Science anxiety was associated with prior achievement, self-efficacy, and science interest, although it did not relate directly to STEM career goals. Gender was found to moderate only the relationship between prior achievement and science self-efficacy.

Advanced Mirror & Modelling Technology Development

Science.gov (United States)

Effinger, Michael; Stahl, H. Philip; Abplanalp, Laura; Maffett, Steven; Egerman, Robert; Eng, Ron; Arnold, William; Mosier, Gary; Blaurock, Carl

2014-01-01

The 2020 Decadal technology survey is starting in 2018. Technology on the shelf at that time will help guide selection to future low risk and low cost missions. The Advanced Mirror Technology Development (AMTD) team has identified development priorities based on science goals and engineering requirements for Ultraviolet Optical near-Infrared (UVOIR) missions in order to contribute to the selection process. One key development identified was lightweight mirror fabrication and testing. A monolithic, stacked, deep core mirror was fused and replicated twice to achieve the desired radius of curvature. It was subsequently successfully polished and tested. A recently awarded second phase to the AMTD project will develop larger mirrors to demonstrate the lateral scaling of the deep core mirror technology. Another key development was rapid modeling for the mirror. One model focused on generating optical and structural model results in minutes instead of months. Many variables could be accounted for regarding the core, face plate and back structure details. A portion of a spacecraft model was also developed. The spacecraft model incorporated direct integration to transform optical path difference to Point Spread Function (PSF) and between PSF to modulation transfer function. The second phase to the project will take the results of the rapid mirror modeler and integrate them into the rapid spacecraft modeler.

Analytical Expressions for Harmonic Distortion at Low Frequencies due to Device Mismatch in CMOS Current Mirrors

DEFF Research Database (Denmark)

Bruun, Erik

1999-01-01

One of the origins of harmonic distortion in current mirrors is the inevitable mismatch between the mirror transistors. In this brief we examine both single current mirrors and complementary class AB current mirrors and develop analytical expressions for the mismatch induced harmonic distortion. ...

Advanced Mirror Technology Development for Very Large Space Telescopes

Science.gov (United States)

Stahl, H. P.

2014-01-01

Advanced Mirror Technology Development (AMTD) is a NASA Strategic Astrophysics Technology project to mature to TRL-6 the critical technologies needed to produce 4-m or larger flight-qualified UVOIR mirrors by 2018 so that a viable mission can be considered by the 2020 Decadal Review. The developed mirror technology must enable missions capable of both general astrophysics & ultra-high contrast observations of exoplanets. Just as JWST’s architecture was driven by launch vehicle, a future UVOIR mission’s architectures (monolithic, segmented or interferometric) will depend on capacities of future launch vehicles (and budget). Since we cannot predict the future, we must prepare for all potential futures. Therefore, to provide the science community with options, we are pursuing multiple technology paths. AMTD uses a science-driven systems engineering approach. We derived engineering specifications for potential future monolithic or segmented space telescopes based on science needs and implement constraints. And we are maturing six inter-linked critical technologies to enable potential future large aperture UVOIR space telescope: 1) Large-Aperture, Low Areal Density, High Stiffness Mirrors, 2) Support Systems, 3) Mid/High Spatial Frequency Figure Error, 4) Segment Edges, 5) Segment-to-Segment Gap Phasing, and 6) Integrated Model Validation Science Advisory Team and a Systems Engineering Team. We are maturing all six technologies simultaneously because all are required to make a primary mirror assembly (PMA); and, it is the PMA’s on-orbit performance which determines science return. PMA stiffness depends on substrate and support stiffness. Ability to cost-effectively eliminate mid/high spatial figure errors and polishing edges depends on substrate stiffness. On-orbit thermal and mechanical performance depends on substrate stiffness, the coefficient of thermal expansion (CTE) and thermal mass. And, segment-to-segment phasing depends on substrate & structure stiffness

Lightweight high-performance 1-4 meter class spaceborne mirrors: emerging technology for demanding spaceborne requirements

Science.gov (United States)

Hull, Tony; Hartmann, Peter; Clarkson, Andrew R.; Barentine, John M.; Jedamzik, Ralf; Westerhoff, Thomas

2010-07-01

Pending critical spaceborne requirements, including coronagraphic detection of exoplanets, require exceptionally smooth mirror surfaces, aggressive lightweighting, and low-risk cost-effective optical manufacturing methods. Simultaneous development at Schott for production of aggressively lightweighted (>90%) Zerodur® mirror blanks, and at L-3 Brashear for producing ultra-smooth surfaces on Zerodur®, will be described. New L-3 techniques for large-mirror optical fabrication include Computer Controlled Optical Surfacing (CCOS) pioneered at L-3 Tinsley, and the world's largest MRF machine in place at L-3 Brashear. We propose that exceptional mirrors for the most critical spaceborne applications can now be produced with the technologies described.

Multilayer active shell mirrors for space telescopes

Science.gov (United States)

Steeves, John; Jackson, Kathryn; Pellegrino, Sergio; Redding, David; Wallace, J. Kent; Bradford, Samuel Case; Barbee, Troy

2016-07-01

A novel active mirror technology based on carbon fiber reinforced polymer (CFRP) substrates and replication techniques has been developed. Multiple additional layers are implemented into the design serving various functions. Nanolaminate metal films are used to provide a high quality reflective front surface. A backing layer of thin active material is implemented to provide the surface-parallel actuation scheme. Printed electronics are used to create a custom electrode pattern and flexible routing layer. Mirrors of this design are thin (traditional optics. Such mirrors could be used as lightweight primaries for small CubeSat-based telescopes or as meter-class segments for future large aperture observatories. Multiple mirrors can be produced under identical conditions enabling a substantial reduction in manufacturing cost and complexity. An overview of the mirror design and manufacturing processes is presented. Predictions on the actuation performance have been made through finite element simulations demonstrating correctabilities on the order of 250-300× for astigmatic modes with only 41 independent actuators. A description of the custom metrology system used to characterize the active mirrors is also presented. The system is based on a Reverse Hartmann test and can accommodate extremely large deviations in mirror figure (> 100 μm PV) down to sub-micron precision. The system has been validated against several traditional techniques including photogrammetry and interferometry. The mirror performance has been characterized using this system, as well as closed-loop figure correction experiments on 150 mm dia. prototypes. The mirrors have demonstrated post-correction figure accuracies of 200 nm RMS (two dead actuators limiting performance).

Sciencey Girls: Discourses Supporting Working-Class Girls to Identify with Science

Science.gov (United States)

Godec, Spela

2018-01-01

Women from working class and some ethnic minority backgrounds continue to be underrepresented in science, particularly in areas such as physical sciences and engineering. Many find it difficult to see science as something that is "for them", which then has implications for their learning and participation in science. In this paper, I…

Nature of Science Lessons, Argumentation and Scientific Discussions among Students in Science Class: A Case Study in a Successful School

Science.gov (United States)

Ozturk, Elif; Ucus, Sukran

2015-01-01

Argumentation is highlighted as one of the most important activities of science education by many researchers. The main aim of this research is to examine primary school students' nature of science classes and argumentation skills in terms of their academic success in primary science classes. Thus, the main interest of the study is centered on the…

Nature of Science Lessons, Argumentation and Scientific Discussions among Students in Science Classes: A Case Study in a Successful School

Science.gov (United States)

Ozturk, Elif; Ucus, Sukran

2015-01-01

Argumentation is highlighted as one of the most important activities of science education by many researchers. The main aim of this research is to examine primary school students' nature of science classes and argumentation skills in terms of their academic success in primary science classes. Thus, the main interest of the study is centered on the…

Variable-delay Polarization Modulators for the CLASS Telescope

Science.gov (United States)

Harrington, Kathleen; Ali, A.; Amiri, M.; Appel, J. W.; Araujo, D.; Bennett, C. L.; Boone, F.; Chan, M.; Cho, H.; Chuss, D. T.; Colazo, F.; Crowe, E.; Denis, K.; Dünner, R.; Eimer, J.; Essinger-Hileman, T.; Gothe, D.; Halpern, M.; Hilton, G.; Hinshaw, G. F.; Huang, C.; Irwin, K.; Jones, G.; Karakla, J.; Kogut, A. J.; Larson, D.; Limon, M.; Lowry, L.; Marriage, T.; Mehrle, N.; Miller, A. D.; Miller, N.; Mirel, P.; Moseley, S. H.; Novak, G.; Reintsema, C.; Rostem, K.; Stevenson, T.; Towner, D.; U-Yen, K.; Wagner, E.; Watts, D.; Wollack, E.; Xu, Z.; Zeng, L.

2014-01-01

The challenges of measuring faint polarized signals at microwave wavelengths have motivated the development of rapid polarization modulators. One scalable technique, called a Variable-delay Polarization Modulator (VPM), consists of a stationary wire array in front of a movable mirror. The mirror motion creates a changing phase difference between the polarization modes parallel and orthogonal to the wire array. The Cosmology Large Angular Scale Surveyor (CLASS) will use a VPM as the first optical element in a telescope array that will search for the signature of inflation through the “B-mode” pattern in the polarization of the cosmic microwave background. In the CLASS VPMs, parallel transport of the mirror is maintained by a voice-coil actuated flexure system which will translate the mirror in a repeatable manner while holding tight parallelism constraints with respect to the wire array. The wire array will use 51 μm diameter copper-plated tungsten wire with 160 μm pitch over a 60 cm clear aperture. We present the status of the construction and testing of the mirror transport mechanism and wire arrays for the CLASS VPMs.

Mirror boxes and mirror mounts for photophysics beamline

International Nuclear Information System (INIS)

Raja Rao, P.M.; Raja Sekhar, B.N.; Das, N.C.; Khan, H.A.; Bhattacharya, S.S.; Roy, A.P.

1996-01-01

Photophysics beamline makes use of one metre Seya-Namioka monochromator and two toroidal mirrors in its fore optics. The first toroidal mirror (pre mirror) focuses light originating from the tangent point of the storage ring onto the entrance slit of the monochromator and second toroidal mirror (post mirror) collects light from the exit slit of the monochromator and focuses light onto the sample placed at a distance of about one metre away from the 2nd mirror. To steer light through monochromator and to focus it on the sample of 1mm x 1mm size require precision rotational and translational motion of the mirrors and this has been achieved with the help of precision mirror mounts. Since Indus-1 operates at pressures less than 10 -9 m.bar, the mirror mounts should be manipulated under similar ultra high vacuum conditions. Considering these requirements, two mirror boxes and two mirror mounts have been designed and fabricated. The coarse movements to the mirrors are imparted from outside the mirror chamber with the help of x-y tables and precision movements to the mirrors are achieved with the help of mirror mounts. The UHV compatibility and performance of the mirror mounts connected to mirror boxes under ultra high vacuum condition is evaluated. The details of the design, fabrication and performance evaluation are discussed in this report. 5 refs., 9 figs., 1 tab

Overview and Summary of the Advanced Mirror Technology Development Project

Science.gov (United States)

Stahl, H. P.

2014-01-01

Advanced Mirror Technology Development (AMTD) is a NASA Strategic Astrophysics Technology project to mature to TRL-6 the critical technologies needed to produce 4-m or larger flight-qualified UVOIR mirrors by 2018 so that a viable mission can be considered by the 2020 Decadal Review. The developed mirror technology must enable missions capable of both general astrophysics & ultra-high contrast observations of exoplanets. Just as JWST’s architecture was driven by launch vehicle, a future UVOIR mission’s architectures (monolithic, segmented or interferometric) will depend on capacities of future launch vehicles (and budget). Since we cannot predict the future, we must prepare for all potential futures. Therefore, to provide the science community with options, we are pursuing multiple technology paths. AMTD uses a science-driven systems engineering approach. We derived engineering specifications for potential future monolithic or segmented space telescopes based on science needs and implement constraints. And we are maturing six inter-linked critical technologies to enable potential future large aperture UVOIR space telescope: 1) Large-Aperture, Low Areal Density, High Stiffness Mirrors, 2) Support Systems, 3) Mid/High Spatial Frequency Figure Error, 4) Segment Edges, 5) Segment-to-Segment Gap Phasing, and 6) Integrated Model Validation Science Advisory Team and a Systems Engineering Team. We are maturing all six technologies simultaneously because all are required to make a primary mirror assembly (PMA); and, it is the PMA’s on-orbit performance which determines science return. PMA stiffness depends on substrate and support stiffness. Ability to cost-effectively eliminate mid/high spatial figure errors and polishing edges depends on substrate stiffness. On-orbit thermal and mechanical performance depends on substrate stiffness, the coefficient of thermal expansion (CTE) and thermal mass. And, segment-to-segment phasing depends on substrate & structure stiffness

Class Size and Academic Achievement in Introductory Political Science Courses

Science.gov (United States)

Towner, Terri L.

2016-01-01

Research on the influence of class size on student academic achievement is important for university instructors, administrators, and students. The article examines the influence of class size--a small section versus a large section--in introductory political science courses on student grades in two comparable semesters. It is expected that…

The academic majors of students taking American soil science classes: 2004-2005 to 2013-2014 academic years

Science.gov (United States)

Brevik, Eric C.; Vaughan, Karen L.; Parikh, Sanjai J.; Dolliver, Holly; Lindbo, David; Steffan, Joshua J.; Weindorf, David; McDaniel, Paul; Mbila, Monday; Edinger-Marshall, Susan

2017-04-01

Many papers have been written in recent years discussing the interdisciplinary and transdisciplinary aspects of soil science. Therefore, it would make sense that soil science courses would be taken by students in a wide array of academic majors. To investigate this, we collected data from eight different American universities on the declared academic majors of students enrolled in soil science courses over a 10 year time period (2004-2005 to 2013-2014 academic years). Data was collected for seven different classes taught at the undergraduate level: introduction to soil science, soil fertility, soil management, pedology, soil biology/microbiology, soil chemistry, and soil physics. Overall trends and trends for each class were evaluated. Generally, environmental science and crop science/horticulture/agronomy students were enrolled in soil science courses in the greatest numbers. Environmental science and engineering students showed rapid increases in enrollment over the 10 years of the study, while the number of crop science/ horticulture/ agronomy students declined. In the introduction to soil science classes, environmental science and crop science/ horticulture/ agronomy students were enrolled in the greatest numbers, while declared soil science majors only made up 6.6% of the average enrollment. The highest enrollments in soil fertility were crop science/ horticulture/ agronomy students and other agricultural students (all agricultural majors except crop science, horticulture, agronomy, or soil science). In both the soil management and pedology classes, environmental science and other agricultural students were the largest groups enrolled. Other agricultural students and students from other majors (all majors not otherwise expressly investigated) were the largest enrolled groups in soil biology/microbiology courses, and environmental science and soil science students were the largest enrolled groups in soil chemistry classes. Soil physics was the only class

New facilities for Al+MgF2 coating for 2-m class mirrors for UV

Science.gov (United States)

Zhupanov, Valery; Vlasenko, Oleg; Sachkov, Mikhail; Fedoseev, Viktor

2014-07-01

The World Space Observatory--Ultraviolet (WSO--UV) project is a Russian-Spanish space mission for spectroscopic and imaging observations in the UV domain (115-320 nm) where some of the most important astrophysical processes can be efficiently studied with unprecedented capability. In the horizon of the next decade, WSO--UV will be the only mission with the large primary mirror fully devoted for UV studies. The observatory includes a 170 cm aperture telescope capable of high-resolution spectroscopy, long slit low-resolution spectroscopy, and deep UV imaging. The telescope T-170M is a Ritchey-Chrétien with a F/10 focal ratio and a corrected field of view of 0.5 degrees. Specific data on the WSO-UV project (telescope, satellite, orbit, launcher, ground segment, etc.) are given in [1-6]. The current status of the WSO-UV focal plane instruments, their status of implementation, and the expected performances are presented in [7]. The science drivers of the WSO-UV mission are described in [8, 9]. The main WSO-UV instruments, spectrographs (WUVS instrument) and imagers (ISSIS instrument) are described in [10-13] and [14-15] correspondingly. The prospects of stellar studies with WSO-UV are presented in papers [16-17]. A paper [18] describes our experience of using the DP-190 glue for adhesive attachment of a large space mirror and its rim. In the instrument compartment, see Figure 1, the optical bench (OB) - used as reference plane for all the onboard instrumentation - is aligned and maintained in the correct position with respect to the primary mirror (PM) using a three rods system. An imaging instrument ISSIS is mounted on the upper basis of the optical bench, in the space available between the PM and the OB itself, while spectrographs (WUVS instrument) are mounted to the OB bottom basis. One of the primary tasks in creating telescope's PM is to apply coating with required reflective and protective properties. Aluminum is a well known reflecting coating for wavelength

STEM for Non-STEM Majors: Enhancing Science Literacy in Large Classes

Science.gov (United States)

Jin, Guang; Bierma, Tom

2013-01-01

This study evaluated a strategy using "clickers," POGIL (process oriented guided inquiry learning), and a focused science literacy orientation in an applied science course for non-STEM undergraduates taught in large classes. The effectiveness of these interventions in improving the science literacy of students was evaluated using a…

Mirroring

DEFF Research Database (Denmark)

Wegener, Charlotte; Wegener, Gregers

2016-01-01

and metaphorical value of mirroring for creativity theory across two different research fields — neuroscience and learning. We engage in a mutual (possibly creative) exploration of mirroring from ‘mirror neurons’ to mirroring in social learning theory. One of the most fascinating aspects of mirroring...... as a neurobiological and as a learning phenomenon is that it points to the embodied and unconscious aspects of social interaction. Thus, mirroring should not be reduced to the non-creative, mechanical repetition of the original, outstanding creativity. To mirror is a human capability built into our capacity to create......Most definitions of creativity emphasise originality. The creative product is recognised as distinct from other products and the creative person as someone who stands out from the crowd. What tend to be overlooked are acts of mirroring as a crucial element of the creative process. The human ability...

Hi-speed compact deformable mirror: status, applications, and perspectives

Science.gov (United States)

Rooms, F.; Camet, S.; Curis, J.-F.

2010-02-01

Membrane deformable mirrors based on magnetic actuators have been known for years. State-of-the-art deformable mirrors usually have large strokes but low bandwidth. Furthermore, this bandwidth decreases with the diameter. In this paper, we present the results of a new actuator principle based on magnetic forces allowing high bandwidth (up to a few kHz), very large stroke (>30μm) with a record pitch of 1.5mm. The benefits of this technology will be presented for three applications: astronomy, vision science and microscopy. The parameters of the mirrors have been tuned such that the inter-actuator stroke of the deformable (more than 2.0μm) in order to fit the atmosphere turbulence characteristics. In vision science, efforts have been made to correct both simultaneously the low and high order aberrations (more than 45μm of wavefront correction on astigmatism and focus). Finally, we will demonstrate how we have developed a deformable mirror able to correct spherical aberrations (microscopy). The last part of the article is devoted to give some perspectives about this technology.

Speaking with a mirror: engagement of mirror neurons via choral speech and its derivatives induces stuttering inhibition.

Science.gov (United States)

Kalinowski, Joseph; Saltuklaroglu, Tim

2003-04-01

'Choral speech', 'unison speech', or 'imitation speech' has long been known to immediately induce reflexive, spontaneous, and natural sounding fluency, even the most severe cases of stuttering. Unlike typical post-therapeutic speech, a hallmark characteristic of choral speech is the sense of 'invulnerability' to stuttering, regardless of phonetic context, situational environment, or audience size. We suggest that choral speech immediately inhibits stuttering by engaging mirror systems of neurons, innate primitive neuronal substrates that dominate the initial phases of language development due to their predisposition to reflexively imitate gestural action sequences in a fluent manner. Since mirror systems are primordial in nature, they take precedence over the much later developing stuttering pathology. We suggest that stuttering may best be ameliorated by reengaging mirror neurons via choral speech or one of its derivatives (using digital signal processing technology) to provide gestural mirrors, that are nature's way of immediately overriding the central stuttering block. Copyright 2003 Elsevier Science Ltd.

N=1 Mirror Symmetry and Open/Closed String Duality

CERN Document Server

Mayr, Peter

2002-01-01

We show that the exact N=1 superpotential of a class of 4d string compactifications is computed by the closed topological string compactified to two dimensions. A relation to the open topological string is used to define a special geometry for N=1 mirror symmetry. Flat coordinates, an N=1 mirror map for chiral multiplets and the exact instanton corrected superpotential are obtained from the periods of a system of differential equations. The result points to a new class of open/closed string dualities which map individual string world-sheets with boundary to ones without. It predicts an mathematically unexpected coincidence of the closed string Gromov-Witten invariants of one Calabi-Yau geometry with the open string invariants of the dual Calabi-Yau.

Construction and Validation of an Instrument to Measure Taiwanese Elementary Students' Attitudes toward Their Science Class

Science.gov (United States)

Wang, Tzu-Ling; Berlin, Donna

2010-12-01

The main purpose of this study is to develop a valid and reliable instrument for measuring the attitudes toward science class of fourth- and fifth-grade students in an Asian school culture. Specifically, the development focused on three science attitude constructs-science enjoyment, science confidence, and importance of science as related to science class experiences. A total of 265 elementary school students in Taiwan responded to the instrument developed. Data analysis indicated that the instrument exhibited satisfactory validity and reliability with the Taiwan population used. The Cronbach's alpha coefficient was 0.93 for the entire instrument indicating a satisfactory level of internal consistency. However, both principal component analysis and parallel analysis showed that the three attitude scales were not unique and should be combined and used as a general "attitudes toward science class" scale. The analysis also showed that there were no gender or grade-level differences in students' overall attitudes toward science class.

Instructional quality of lower grades natural science classes: the ...

African Journals Online (AJOL)

... classes: the case of primary schools linked to Kemise College of Teacher Education. ... the quality of natural science education classroom instruction in lower grade ... on pedagogical and subject matter issue, closer support and supervision.

Mirror, mirror on the wall

CERN Multimedia

2005-01-01

RICH 2, one of the two Ring Imaging Cherenkov detectors of the LHCb experiment, is being prepared to join the other detector elements ready for the first proton-proton collisions at LHC. The mirrors of the RICH2 detector are meticulously assembled in a clean room.In a large dark room, men in white move around an immense structure some 7 metres high, 10 metres wide and nearly 2.5 metres deep. Apparently effortlessly, they are installing the two large high-precision spherical mirrors. These mirrors will focus Cherenkov light, created by the charged particles that will traverse this detector, onto the photon detectors. Each spherical mirror wall is made up of facets like a fly's eye. Twenty-eight individual thin glass mirrors will all point to the same point in space to within a few micro-radians. The development of these mirrors has been technically demanding : Ideally they should be massless, sturdy, precise and have high reflectivity. In practice, though not massless, they are made from a mere 6 mm thin gl...

Kilowatt-Class Fission Power Systems for Science and Human Precursor Missions

Science.gov (United States)

Mason, Lee S.; Gibson, Marc Andrew; Poston, Dave

2013-01-01

Nuclear power provides an enabling capability for NASA missions that might otherwise be constrained by power availability, mission duration, or operational robustness. NASA and the Department of Energy (DOE) are developing fission power technology to serve a wide range of future space uses. Advantages include lower mass, longer life, and greater mission flexibility than competing power system options. Kilowatt-class fission systems, designated "Kilopower," were conceived to address the need for systems to fill the gap above the current 100-W-class radioisotope power systems being developed for science missions and below the typical 100-k We-class reactor power systems being developed for human exploration missions. This paper reviews the current fission technology project and examines some Kilopower concepts that could be used to support future science missions or human precursors.

Mirror-Image Equivalence and Interhemispheric Mirror-Image Reversal.

Science.gov (United States)

Corballis, Michael C

2018-01-01

Mirror-image confusions are common, especially in children and in some cases of neurological impairment. They can be a special impediment in activities such as reading and writing directional scripts, where mirror-image patterns (such as b and d ) must be distinguished. Treating mirror images as equivalent, though, can also be adaptive in the natural world, which carries no systematic left-right bias and where the same object or event can appear in opposite viewpoints. Mirror-image equivalence and confusion are natural consequences of a bilaterally symmetrical brain. In the course of learning, mirror-image equivalence may be established through a process of symmetrization, achieved through homotopic interhemispheric exchange in the formation of memory circuits. Such circuits would not distinguish between mirror images. Learning to discriminate mirror-image discriminations may depend either on existing brain asymmetries, or on extensive learning overriding the symmetrization process. The balance between mirror-image equivalence and mirror-image discrimination may nevertheless be precarious, with spontaneous confusions or reversals, such as mirror writing, sometimes appearing naturally or as a manifestation of conditions like dyslexia.

Mirror-Image Equivalence and Interhemispheric Mirror-Image Reversal

Directory of Open Access Journals (Sweden)

Michael C. Corballis

2018-04-01

Full Text Available Mirror-image confusions are common, especially in children and in some cases of neurological impairment. They can be a special impediment in activities such as reading and writing directional scripts, where mirror-image patterns (such as b and d must be distinguished. Treating mirror images as equivalent, though, can also be adaptive in the natural world, which carries no systematic left-right bias and where the same object or event can appear in opposite viewpoints. Mirror-image equivalence and confusion are natural consequences of a bilaterally symmetrical brain. In the course of learning, mirror-image equivalence may be established through a process of symmetrization, achieved through homotopic interhemispheric exchange in the formation of memory circuits. Such circuits would not distinguish between mirror images. Learning to discriminate mirror-image discriminations may depend either on existing brain asymmetries, or on extensive learning overriding the symmetrization process. The balance between mirror-image equivalence and mirror-image discrimination may nevertheless be precarious, with spontaneous confusions or reversals, such as mirror writing, sometimes appearing naturally or as a manifestation of conditions like dyslexia.

Mirror Neurons and Mirror-Touch Synesthesia.

Science.gov (United States)

Linkovski, Omer; Katzin, Naama; Salti, Moti

2016-05-30

Since mirror neurons were introduced to the neuroscientific community more than 20 years ago, they have become an elegant and intuitive account for different cognitive mechanisms (e.g., empathy, goal understanding) and conditions (e.g., autism spectrum disorders). Recently, mirror neurons were suggested to be the mechanism underlying a specific type of synesthesia. Mirror-touch synesthesia is a phenomenon in which individuals experience somatosensory sensations when seeing someone else being touched. Appealing as it is, careful delineation is required when applying this mechanism. Using the mirror-touch synesthesia case, we put forward theoretical and methodological issues that should be addressed before relying on the mirror-neurons account. © The Author(s) 2016.

Girls' and Boys' Academic Self-Concept in Science in Single-Sex and Coeducational Classes

Science.gov (United States)

Simpson, Amber; Che, S. Megan; Bridges, William C., Jr.

2016-01-01

Recently, single-sex classes within public coeducational schools have proliferated across the USA; yet, we still know little about whether and how single-sex science classes influence adolescents' attitude and affect toward science. This exploratory study expands upon our current understanding by investigating the extent in which female and male…

Mirror monochromator

Energy Technology Data Exchange (ETDEWEB)

Mankos, Marian [Electron Optica, Inc., Palo Alto, CA (United States); Shadman, Khashayar [Electron Optica, Inc., Palo Alto, CA (United States)

2014-12-02

energy of 80-120 keV). Specialized software packages that have been developed by MEBS, Ltd. were used to calculate the electron optical properties of the key monochromator components: namely, the magnetic prism, the electron mirror, and the electron lenses. In the final step, these results were folded into a model describing the key electron-optical parameters of the complete monochromator. The simulations reveal that the mirror monochromator can reduce the energy spread of a Schottky electron source, an established electron emitter used widely in EMs, to 10 meV for practical beam current values and that further reduction of the energy spread down to 3 meV is possible for low current applications with a Cold Field Emitter (an electron source with 10x the brightness of a Schottky source). MirrorChroms can be designed and built to attach to different types of TEMs and SEMs, thus making them suitable for enhancing the study of the structure, composition, and bonding states of new materials at the nanoscale to advance material science research in the field of nanotechnology as well as biomedical research.

Comparison of shipping, handling, and shock instrumentation results for two 3.5-m-class primary mirrors

Science.gov (United States)

Killpatrick, Don H.; Mayo, James W.

1998-08-01

Packing, shipping, and handling procedures employed during several transportation activities for two large telescope primary mirrors are presented along with detailed shock recording results. Operations monitored included craning, forklifting, and shipping by air, sea, and land during all phases of manufacture and installation. The mirrors monitored were the SOR 3.5-m Telescope spun cast borosilicate primary mirror and the AEOS 3.67-m Telescope Zerodur thin meniscus primary mirror. Shock recording instrumentation included 2-, 5-, and 10-g Omni-G(superscript TM) impact indicators, 10-g Impact o-graph(superscript TM) 3-axis recording accelerometers, and high-resolution 3-axis accelerometers with Astromed Dash 8 eight-channel chart recorders and audio indicators. Shock results for some operations were monitored to the 0.01-g level. In-shipment temperature data are also presented and discussed. Effects of lifting operations, road conditions via truck, flight conditions via C-5B aircraft, and transportation via sea- going barge are discussed. Data are presented for three different crate designs and configurations and, in some cases, include mirror-in-cell shipping data. Shock results were observed from as low as a few hundredths-g to over 3- g's during various operations.

Advanced UVOIR Mirror Technology Development (AMTD) for Very Large Space Telescopes

Science.gov (United States)

Stahl, H. Philip; Smith, W. Scott; Mosier, Gary; Abplanalp, Laura; Arnold, William

2014-01-01

ASTRO2010 Decadal stated that an advanced large-aperture ultraviolet, optical, near-infrared (UVOIR) telescope is required to enable the next generation of compelling astrophysics and exoplanet science; and, that present technology is not mature enough to affordably build and launch any potential UVOIR mission concept. AMTD builds on the state of art (SOA) defined by over 30 years of monolithic & segmented ground & space-telescope mirror technology to mature six key technologies. AMTD is deliberately pursuing multiple design paths to provide the science community with op-tions to enable either large aperture monolithic or segmented mirrors with clear engineering metrics traceable to science requirements.

Do Thinking Styles Matter for Science Achievement and Attitudes toward Science Class in Male and Female Elementary School Students in Taiwan?

Science.gov (United States)

Wang, Tzu-Ling; Tseng, Yi-Kuan

2015-01-01

The purposes of this study were to explore the effects of thinking styles on science achievement and attitudes toward science class among Taiwanese elementary school students and to explore the differences between male and female students in their modes of thinking. Participants included 756 sixth-grade students from 28 classes in four elementary…

My Body and Its Reflection: A Case Study of Eight Dance Students and the Mirror in the Ballet Classroom

Science.gov (United States)

Radell, Sally Anne; Keneman, Margaret Lynn; Adame, Daniel D.; Cole, Steven P.

2014-01-01

This qualitative study investigated the impact of the mirror on a dancer's body image. Two groups of students enrolled in beginner ballet classes were taught the same classroom material; one group was taught with mirrors, the other, without. At the end of the semester four students from each class were randomly selected to participate in a private…

Beating the numbers through strategic intervention materials (SIMs): Innovative science teaching for large classes

Science.gov (United States)

Alboruto, Venus M.

2017-05-01

The study aimed to find out the effectiveness of using Strategic Intervention Materials (SIMs) as an innovative teaching practice in managing large Grade Eight Science classes to raise the performance of the students in terms of science process skills development and mastery of science concepts. Utilizing experimental research design with two groups of participants, which were purposefully chosen, it was obtained that there existed a significant difference in the performance of the experimental and control groups based on actual class observation and written tests on science process skills with a p-value of 0.0360 in favor of the experimental class. Further, results of written pre-test and post-test on science concepts showed that the experimental group with the mean of 24.325 (SD =3.82) performed better than the control group with the mean of 20.58 (SD =4.94), with a registered p-value of 0.00039. Therefore, the use of SIMs significantly contributed to the mastery of science concepts and the development of science process skills. Based on the findings, the following recommendations are offered: 1. that grade eight science teachers should use or adopt the SIMs used in this study to improve their students' performance; 2. training-workshop on developing SIMs must be conducted to help teachers develop SIMs to be used in their classes; 3. school administrators must allocate funds for the development and reproduction of SIMs to be used by the students in their school; and 4. every division should have a repository of SIMs for easy access of the teachers in the entire division.

Argumentation in Science Class: Its Planning, Practice, and Effect on Student Motivation

Science.gov (United States)

Taneja, Anju

Studies have shown an association between argumentative discourse in science class, better understanding of science concepts, and improved academic performance. However, there is lack of research on how argumentation can increase student motivation. This mixed methods concurrent nested study uses Bandura's construct of motivation and concepts of argumentation and formative feedback to understand how teachers orchestrate argumentation in science class and how it affects motivation. Qualitative data was collected through interviews of 4 grade-9 science teachers and through observing teacher-directed classroom discourse. Classroom observations allowed the researcher to record the rhythm of discourse by characterizing teacher and student speech as teacher presentation (TP), teacher guided authoritative discussion (AD), teacher guided dialogic discussion (DD), and student initiation (SI). The Student Motivation Towards Science Learning survey was administered to 67 students before and after a class in which argumentation was used. Analysis of interviews showed teachers collaborated to plan argumentation. Analysis of discourse identified the characteristics of argumentation and provided evidence of students' engagement in argumentation in a range of contexts. Student motivation scores were tested using Wilcoxon signed rank tests and Mann-Whitney U-tests, which showed no significant change. However, one construct of motivation---active learning strategy---significantly increased. Quantitative findings also indicate that teachers' use of multiple methods in teaching science can affect various constructs of students' motivation. This study promotes social change by providing teachers with insight about how to engage all students in argumentation.

Multiple-Choice Exams: An Obstacle for Higher-Level Thinking in Introductory Science Classes

Science.gov (United States)

Stanger-Hall, Kathrin F.

2012-01-01

Learning science requires higher-level (critical) thinking skills that need to be practiced in science classes. This study tested the effect of exam format on critical-thinking skills. Multiple-choice (MC) testing is common in introductory science courses, and students in these classes tend to associate memorization with MC questions and may not see the need to modify their study strategies for critical thinking, because the MC exam format has not changed. To test the effect of exam format, I used two sections of an introductory biology class. One section was assessed with exams in the traditional MC format, the other section was assessed with both MC and constructed-response (CR) questions. The mixed exam format was correlated with significantly more cognitively active study behaviors and a significantly better performance on the cumulative final exam (after accounting for grade point average and gender). There was also less gender-bias in the CR answers. This suggests that the MC-only exam format indeed hinders critical thinking in introductory science classes. Introducing CR questions encouraged students to learn more and to be better critical thinkers and reduced gender bias. However, student resistance increased as students adjusted their perceptions of their own critical-thinking abilities. PMID:22949426

Performance of lightweight large C/SiC mirror

Science.gov (United States)

Yui, Yukari Y.; Goto, Ken; Kaneda, Hidehiro; Katayama, Haruyoshi; Kotani, Masaki; Miyamoto, Masashi; Naitoh, Masataka; Nakagawa, Takao; Saruwatari, Hideki; Suganuma, Masahiro; Sugita, Hiroyuki; Tange, Yoshio; Utsunomiya, Shin; Yamamoto, Yasuji; Yamawaki, Toshihiko

2017-11-01

Very lightweight mirror will be required in the near future for both astronomical and earth science/observation missions. Silicon carbide is becoming one of the major materials applied especially to large and/or light space-borne optics, such as Herschel, GAIA, and SPICA. On the other hand, the technology of highly accurate optical measurement of large telescopes, especially in visible wavelength or cryogenic circumstances is also indispensable to realize such space-borne telescopes and hence the successful missions. We have manufactured a very lightweight Φ=800mm mirror made of carbon reinforced silicon carbide composite that can be used to evaluate the homogeneity of the mirror substrate and to master and establish the ground testing method and techniques by assembling it as the primary mirror into an optical system. All other parts of the optics model are also made of the same material as the primary mirror. The composite material was assumed to be homogeneous from the mechanical tests of samples cut out from the various areas of the 800mm mirror green-body and the cryogenic optical measurement of the mirror surface deformation of a 160mm sample mirror that is also made from the same green-body as the 800mm mirror. The circumstance and condition of the optical testing facility has been confirmed to be capable for the highly precise optical measurements of large optical systems of horizontal light axis configuration. Stitching measurement method and the algorithm for analysis of the measurement is also under study.

Strategic Note-Taking for Middle-School Students with Learning Disabilities in Science Classes

Science.gov (United States)

Boyle, Joseph R.

2010-01-01

While today's teachers use a variety of teaching methods in middle-school science classes, lectures and note-taking still comprise a major portion of students' class time. To be successful in these classes, middle-school students need effective listening and note-taking skills. Students with learning disabilities (LD) are poor note-takers, which…

Ballooning instabilities in toroidally linked mirror systems

International Nuclear Information System (INIS)

Hastie, R.J.; Watson, C.J.H.

1977-01-01

This paper examines the stability against ballooning modes of plasma equilibria in toroidally linked mirror configurations consisting of a number of quadrupole minimum-B mirrors linked toroidally. On the basis of the Kruskal-Oberman energy principle, a class of displacements is identified which are potentially unstable, and a necessary criterion for stability is derived. The criterion is obtained from the eigenvalues of an ordinary differential equation, which determines the variation of the displacement along a field line. The coefficients in the equation are determined by the configuration, and by inserting various model configurations, estimates are obtained of the maximum value of β consistent with stability. In cases of interest, quite high β-values are obtained. (author)

Mothers as informal science class teachers

Science.gov (United States)

Katz, Phyllis

education class. Study outcomes include self-reported tendencies toward increased awareness of science teaching techniques and content, as well as pleasure, confidence, and family interactions around science. The survey amplifies these findings among a larger group. Negative cases and difficulties are discussed. This study suggests that the availability of mothers' informal science teaching/learning experience is one way to create a more pervasively supportive environment for science education. There is increased opportunity for women as adult learners, to be positive role models, and to mediate family settings. Recommendations are made for recruiting mothers as teachers and fulfilling their motivations. Informal science education theory is discussed

[Mirror neurons: from anatomy to pathophysiological and therapeutic implications].

Science.gov (United States)

Mathon, B

2013-04-01

Mirror neurons are a special class of neurons discovered in the 1990s. They respond when we perform an action and also when we see someone else perform that action. They play a role in the pathophysiology of some neuropsychiatric diseases. Mirror neurons have been identified in humans: in Broca's area and the inferior parietal cortex. Their responses are qualitative and selective depending on the observed action. Emotions (including disgust) and empathy seem to operate according to a mirror mechanism. Indeed, the mirror system allows us to encode the sensory experience and to simulate the emotional state of others. This results in our improved identification of the emotions in others. Additionally, mirror neurons can encode an observed action in motor stimuli and allow its reproduction; thus, they are involved in imitation and learning. Current studies are assessing the role of mirror neurons in the pathopysiology of social-behavior disorders, including autism and schizophrenia. Understanding this mirror system will allow us to develop psychotherapy practices based on empathic resonance between the patient and the therapist. Also, some authors report that a passive rehabilitation technique, based on stimulation of the mirror-neuron system, has a beneficial effect in the treatment of patients with post-stroke motor deficits. Mirror neurons are an anatomical entity that enables improved understanding of behavior and emotions, and serves as a base for developing new cognitive therapies. Additional studies are needed to clarify the exact role of this neuronal system in social cognition and its role in the development of some neuropsychiatric diseases. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Class-first analysis in a continuum: an approach to the complexities of schools, society, and insurgent science

Science.gov (United States)

Valdiviezo, Laura Alicia

2010-06-01

This essay addresses Katherine Richardson Bruna's paper: Mexican Immigrant Transnational Social Capital and Class Transformation: Examining the Role of Peer Mediation in Insurgent Science, through five main points . First, I offer a comparison between the traditional analysis of classism in Latin America and Richardson Bruna's call for a class-first analysis in the North American social sciences where there has been a tendency to obviate the specific examination of class relations and class issues. Secondly, I discuss that a class-first analysis solely cannot suffice to depict the complex dimensions in the relations of schools and society. Thus, I suggest a continuum in the class-first analysis. Third, I argue that social constructions surrounding issues of language, ethnicity, and gender necessarily intersect with issues of class and that, in fact, those other constructions offer compatible epistemologies that aid in representing the complexity of social and institutional practices in the capitalist society. Richardson Bruna's analysis of Augusto's interactions with his teacher and peers in the science class provides a fourth point of discussion in this essay. As a final point in my response I discuss Richardson Bruna's idea of making accessible class-first analysis knowledge to educators and especially to science teachers.

Confirmatory factors analysis of science teacher leadership in the Thailand world-class standard schools

Science.gov (United States)

Thawinkarn, Dawruwan

2018-01-01

This research aims to analyze factors of science teacher leadership in the Thailand World-Class Standard Schools. The research instrument was a five scale rating questionnaire with reliability 0.986. The sample group included 500 science teachers from World-Class Standard Schools who had been selected by using the stratified random sampling technique. Factor analysis of science teacher leadership in the Thailand World-Class Standard Schools was conducted by using M plus for Windows. The results are as follows: The results of confirmatory factor analysis on science teacher leadership in the Thailand World-Class Standard Schools revealed that the model significantly correlated with the empirical data. The consistency index value was x2 = 105.655, df = 88, P-Value = 0.086, TLI = 0.997, CFI = 0.999, RMSEA = 0.022, and SRMR = 0.019. The value of factor loading of science teacher leadership was positive, with statistical significance at the level of 0.01. The value of six factors was between 0.880-0.996. The highest factor loading was the professional learning community, followed by child-centered instruction, participation in development, the role model in teaching, transformational leaders, and self-development with factor loading at 0.996, 0.928, 0.911, 0.907, 0.901, and 0.871, respectively. The reliability of each factor was 99.1%, 86.0%, 83.0%, 82.2%, 81.0%, and 75.8%, respectively.

Imitation, mirror neurons and autism

OpenAIRE

Williams, Justin H.G.; Whiten, Andrew; Suddendorf, Thomas; Perrett, David I.

2001-01-01

Various deficits in the cognitive functioning of people with autism have been documented in recent years but these provide only partial explanations for the condition. We focus instead on an imitative disturbance involving difficulties both in copying actions and in inhibiting more stereotyped mimicking, such as echolalia. A candidate for the neural basis of this disturbance may be found in a recently discovered class of neurons in frontal cortex, 'mirror neurons' (MNs). These neurons show ac...

Mirror fusion reactors

International Nuclear Information System (INIS)

Carlson, G.A.; Moir, R.W.

1978-01-01

We have carried out conceptual design studies of fusion reactors based on the three current mirror confinement concepts: the standard mirror, the tandem mirror, and the field-reversed mirror. Recent studies of the standard mirror have emphasized its potential as a fusion-fission hybrid reactor, designed to produce fission fuel for fission reactors. We have designed a large commercial hybrid based on standard mirror confinement, and also a small pilot plant hybrid. Tandem mirror designs include a commercial 1000 MWe fusion power plant and a nearer term tandem mirror hybrid. Field-reversed mirror designs include a multicell commercial reactor producing 75 MWe and a single cell pilot plant

Mirror fusion reactors

International Nuclear Information System (INIS)

Anon.

1978-01-01

Conceptual design studies were made of fusion reactors based on the three current mirror-confinement concepts: the standard mirror, the tandem mirror, and the field-reversed mirror. Recent studies of the standard mirror have emphasized its potential as a fusion-fission hybrid reactor, designed to produce fuel for fission reactors. We have designed a large commercial hybrid and a small pilot-plant hybrid based on standard mirror confinement. Tandem mirror designs include a commercial 1000-MWe fusion power plant and a nearer term tandem mirror hybrid. Field-reversed mirror designs include a multicell commercial reactor producing 75 MWe and a single-cell pilot plant

Chiral mirrors

International Nuclear Information System (INIS)

Plum, Eric; Zheludev, Nikolay I.

2015-01-01

Mirrors are used in telescopes, microscopes, photo cameras, lasers, satellite dishes, and everywhere else, where redirection of electromagnetic radiation is required making them arguably the most important optical component. While conventional isotropic mirrors will reflect linear polarizations without change, the handedness of circularly polarized waves is reversed upon reflection. Here, we demonstrate a type of mirror reflecting one circular polarization without changing its handedness, while absorbing the other. The polarization-preserving mirror consists of a planar metasurface with a subwavelength pattern that cannot be superimposed with its mirror image without being lifted out of its plane, and a conventional mirror spaced by a fraction of the wavelength from the metasurface. Such mirrors enable circularly polarized lasers and Fabry-Pérot cavities with enhanced tunability, gyroscopic applications, polarization-sensitive detectors of electromagnetic waves, and can be used to enhance spectroscopies of chiral media

Mirror agnosia and the mirrored-self misidentification delusion: a hypnotic analogue.

Science.gov (United States)

Connors, Michael H; Cox, Rochelle E; Barnier, Amanda J; Langdon, Robyn; Coltheart, Max

2012-05-01

Mirrored-self misidentification is the delusional belief that one's reflection in the mirror is a stranger. Current theories suggest that one pathway to the delusion is mirror agnosia (a deficit in which patients are unable to use mirror knowledge when interacting with mirrors). This study examined whether a hypnotic suggestion for mirror agnosia can recreate features of the delusion. Ten high hypnotisable participants were given either a suggestion to not understand mirrors or to see the mirror as a window. Participants were asked to look into a mirror and describe what they saw. Participants were tested on their understanding of mirrors and received a series of challenges. Participants then received a detailed postexperimental inquiry. Three of five participants given the suggestion to not understand mirrors reported seeing a stranger and maintained this belief when challenged. These participants also showed signs of mirror agnosia. No participants given the suggestion to see a window reported seeing a stranger. Results indicate that a hypnotic suggestion for mirror agnosia can be used to recreate the mirrored-self misidentification delusion. Factors influencing the effectiveness of hypnotic analogues of psychopathology, such as participants' expectations and interpretations, are discussed.

Mirror profile optimization for nano-focusing KB mirror

International Nuclear Information System (INIS)

Zhang Lin; Baker, Robert; Barrett, Ray; Cloetens, Peter; Dabin, Yves

2010-01-01

A KB focusing mirror width profile has been optimized to achieve nano-focusing for the nano-imaging end-station ID22NI at the ESRF. The complete mirror and flexure bender assembly has been modeled in 3D with finite element analysis using ANSYS. Bender stiffness, anticlastic effects and geometrical non-linear effects have been considered. Various points have been studied: anisotropy and crystal orientation, stress in the mirror and bender, actuator resolution and the mirror-bender adhesive bonding... Extremely high performance of the mirror is expected with residual slope error smaller than 0.6 μrad, peak-to-valley, compared to the bent slope of 3000 μrad.

Timecourse of mirror and counter-mirror effects measured with transcranial magnetic stimulation.

Science.gov (United States)

Cavallo, Andrea; Heyes, Cecilia; Becchio, Cristina; Bird, Geoffrey; Catmur, Caroline

2014-08-01

The human mirror system has been the subject of much research over the past two decades, but little is known about the timecourse of mirror responses. In addition, it is unclear whether mirror and counter-mirror effects follow the same timecourse. We used single-pulse transcranial magnetic stimulation to investigate the timecourse of mirror and counter-mirror responses in the human brain. Experiment 1 demonstrated that mirror responses can be measured from around 200 ms after observed action onset. Experiment 2 demonstrated significant effects of counter-mirror sensorimotor training at all timepoints at which a mirror response was found in Experiment 1 (i.e. from 200 ms onward), indicating that mirror and counter-mirror responses follow the same timecourse. By suggesting similarly direct routes for mirror and counter-mirror responses, these results support the associative account of mirror neuron origins whereby mirror responses arise as a result of correlated sensorimotor experience during development. More generally, they contribute to theorizing regarding mirror neuron function by providing some constraints on how quickly mirror responses can influence social cognition. © The Author (2013). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Prototyping iridium coated mirrors for x-ray astronomy

Science.gov (United States)

Döhring, Thorsten; Probst, Anne-Catherine; Stollenwerk, Manfred; Emmerich, Florian; Stehlíková, Veronika; Inneman, Adolf

2017-05-01

X-ray astronomy uses space-based telescopes to overcome the disturbing absorption of the Earth's atmosphere. The telescope mirrors are operating at grazing incidence angles and are coated with thin metal films of high-Z materials to get sufficient reflectivity for the high-energy radiation to be observed. In addition the optical payload needs to be light-weighted for launcher mass constrains. Within the project JEUMICO, an acronym for "Joint European Mirror Competence", the Aschaffenburg University of Applied Sciences and the Czech Technical University in Prague started a collaboration to develop mirrors for X-ray telescopes. The X-ray telescopes currently developed within this Bavarian- Czech project are of Lobster eye type optical design. Corresponding mirror segments use substrates of flat silicon wafers which are coated with thin iridium films, as this material is promising high reflectivity in the X-ray range of interest. The deposition of the iridium films is based on a magnetron sputtering process. Sputtering with different parameters, especially by variation of the argon gas pressure, leads to iridium films with different properties. In addition to investigations of the uncoated mirror substrates the achieved surface roughness has been studied. Occasional delamination of the iridium films due to high stress levels is prevented by chromium sublayers. Thereby the sputtering parameters are optimized in the context of the expected reflectivity of the coated X-ray mirrors. In near future measurements of the assembled mirror modules optical performances are planned at an X-ray test facility.

Using a dynamic, introductory-level volcanoes class as a means to introduce non-science majors to the geosciences

Science.gov (United States)

Cook, G. W.

2012-12-01

At the University of California, San Diego, I teach a quarter-long, introductory Earth Science class titled "Volcanoes," which is, in essence, a functional class in volcanology designed specifically for non-majors. This large-format (enrollment ~ 85), lecture-based class provides students from an assortment of backgrounds an opportunity to acquire much-needed (and sometimes dreaded) area credits in science, while also serving as an introduction to the Earth Science major at UCSD (offered through Scripps Institution of Oceanography). The overall goal of the course is to provide students with a stimulating and exciting general science option that, using an inherently interesting topic, introduces them to the fundamentals of geoscience. A secondary goal is to promote general science and geoscience literacy among the general population of UCSD. Student evaluations of this course unequivocally indicate a high degree of learning and interest in the material. The majority of students in the class (>80%) are non-science majors and very few students (degree-seeking students. In addition, only a handful of students have typically had any form of geology class beyond high school level Earth Science. Consequently, there are challenges associated with teaching the class. Perhaps most significantly, students have very little background—background that is necessary for understanding the processes involved in volcanic eruptions. Second, many non-science students have built-in anxieties with respect to math and science, anxieties that must be considered when designing curriculum and syllabi. It is essential to provide the right balance of technical information while remaining in touch with the audience. My approach to the class involves a dynamic lecture format that incorporates a wide array of multimedia, analogue demonstrations of volcanic processes, and small-group discussions of topics and concepts. In addition to teaching about volcanoes—a fascinating subject in and of

ATLAST ULE mirror segment performance analytical predictions based on thermally induced distortions

Science.gov (United States)

Eisenhower, Michael J.; Cohen, Lester M.; Feinberg, Lee D.; Matthews, Gary W.; Nissen, Joel A.; Park, Sang C.; Peabody, Hume L.

2015-09-01

The Advanced Technology Large-Aperture Space Telescope (ATLAST) is a concept for a 9.2 m aperture space-borne observatory operating across the UV/Optical/NIR spectra. The primary mirror for ATLAST is a segmented architecture with pico-meter class wavefront stability. Due to its extraordinarily low coefficient of thermal expansion, a leading candidate for the primary mirror substrate is Corning's ULE® titania-silicate glass. The ATLAST ULE® mirror substrates will be maintained at `room temperature' during on orbit flight operations minimizing the need for compensation of mirror deformation between the manufacturing temperature and the operational temperatures. This approach requires active thermal management to maintain operational temperature while on orbit. Furthermore, the active thermal control must be sufficiently stable to prevent time-varying thermally induced distortions in the mirror substrates. This paper describes a conceptual thermal management system for the ATLAST 9.2 m segmented mirror architecture that maintains the wavefront stability to less than 10 pico-meters/10 minutes RMS. Thermal and finite element models, analytical techniques, accuracies involved in solving the mirror figure errors, and early findings from the thermal and thermal-distortion analyses are presented.

Light and lightened mirrors for astronomy

Science.gov (United States)

Fappani, Denis

2008-07-01

For ground-based astronomy, more and more large telescopes are emerging all around the world. Similarly to space borne telescopes, for which the use of lightened optics has always been a baseline for purpose of mass reduction of payloads, same kinds of lightened/light mirrors are then now more and more intensively used also for ground-based instrumentation for astronomy, requiring larger and larger components. Through several examples of typical past realizations (class 0.5m-1m) for different astronomical projects requiring light or lightened mirrors for different reasons (optimisation of mass and stiffness, reduction of thermal inertia, increasing of dynamic performance for fast scanning purpose,....), the presentation will point out issues for lightening design, manufacturing and control of such parts, as well as brief overview of the corresponding existing "state of the art" for these technologies in SESO.

Classical transport in field reversed mirrors: reactor implications

International Nuclear Information System (INIS)

Auerbach, S.P.; Condit, W.C.

1980-01-01

Assuming that the field-reversed mirror (or the closely related spheromak) turns out to be stable, the next crucial issue is transport of particles and heat. Of particular concern is the field null on axis (the X-point), which at first glance seems to allow particles to flow out unhindered. We have evaluated the classical diffusion coefficients for particles and heat in field-reversed mirrors, with particular reference to a class of Hill's vortex models. Two fairly surprising results emerge from this study. First, the diffusion-driven flow of particles and heat is finite at the X-points. This may be traced to the geometrical constraint that the current (and hence the ion-electron drag force, which causes cross-field transport) must vanish on axis. This conclusion holds for any transport model. Second, the classical diffusion coefficient D(psi), which governs both particle and heat flux, is finite on the separatrix. Indeed, in a wide class of Hill's vortex equilibria (spherical, oblate, or prolate) D(psi) is essentially independent of psi (except for the usual factor of n

Two-mirror Schwarzschild aplanats. Basic relations

OpenAIRE

Terebizh, V. Yu.

2005-01-01

It is shown that the theory of aplanatic two-mirror telescopes developed by Karl Schwarzschild in 1905 leads to the unified description both the prefocal and the postfocal systems. The class of surfaces in the ZEMAX optical program has been properly extended to ascertain the image quality in exact Schwarzschild aplanats. A comparison of Schwarzschild aplanats with approximate Ritchey-Chretien and Gregory-Maksutov aplanatic telescopes reveals a noticeable advantage of the former at fast focal ...

Teaching Writing and Critical Thinking in Large Political Science Classes

Science.gov (United States)

Franklin, Daniel; Weinberg, Joseph; Reifler, Jason

2014-01-01

In the interest of developing a combination of teaching techniques designed to maximize efficiency "and" quality of instruction, we have experimentally tested three separate and relatively common teaching techniques in three large introductory political science classes at a large urban public university. Our results indicate that the…

Multilayer X-ray mirrors for formation of sub-nanometer wavelength range beams

International Nuclear Information System (INIS)

Akhsakhalyan, A.A.; Akhsakhalyan, A.D.; Klyuenkov, E.B.; Murav'ev, V.A.; Salashchenko, N.N.; Kharitonov, A.I.

2005-01-01

Paper reviews the efforts undertaken in the RF Academy of Sciences IPM within recent 5 years to design multilayer mirror systems to produce X-ray wavelength subnanometer range beams. Paper describes a process to fabricate the mentioned systems covering the procedures to obtain supersmooth surfaces of the specified shape, to deposit gradient multilayer structures on the mentioned surfaces and describes the rules to calculate the optimal parameters of mirrors. Paper presents characteristics of mirror system two types: a mirror in the shape of a parabolic cylinder to collimate radiation in the DRON-4, DRON-6 production-type X-ray diffractometers and in the shape of a quadraelliptic reflector - a new wide-aperture four-corner focusing system [ru

Axisymmetric magnetic mirrors for plasma confinement. Recent development and perspectives

International Nuclear Information System (INIS)

Kruglyakov, E.P.; Dimov, G.I.; Ivanov, A.A.; Koidan, V.S.

2003-01-01

Mirrors are the only one class of fusion systems which completely differs topologically from the systems with closed magnetic configurations. At present, three modern types of different mirror machines for plasma confinement and heating exist in Novosibirsk (Gas Dynamic Trap,- GDT, Multi-mirror,- GOL-3, and Tandem Mirror,- AMBAL-M). All these systems are attractive from the engineering point of view because of very simple axisymmetric geometry of magnetic configurations. In the present paper, the status of different confinement systems is presented. The experiments most crucial for the mirror concept are described such as a demonstration of different principles of suppression of electron heat conductivity (GDT, GOL-3), finding of MHD stable regimes of plasma confinement in axisymmetric geometry of magnetic field (GDT, AMBAL-M), an effective heating of a dense plasma by relativistic electron beam (GOL-3), observation of radial diffusion of quiescent plasma with practically classical diffusion coefficient (AMBAL-M), etc. It should be mentioned that on the basis of the GDT it is possible to make a very important intermediate step. Using 'warm' plasma and oblique injection of fast atoms of D and T one can create a powerful 14 MeV neutron source with a moderate irradiation area (about 1 square meter) and, accordingly, with low tritium consumption. The main plasma parameters achieved are presented and the future perspectives of different mirror machines are outlined. (author)

Emotional climate of a pre-service science teacher education class in Bhutan

Science.gov (United States)

Rinchen, Sonam; Ritchie, Stephen M.; Bellocchi, Alberto

2016-09-01

This study explored pre-service secondary science teachers' perceptions of classroom emotional climate in the context of the Bhutanese macro-social policy of Gross National Happiness. Drawing upon sociological perspectives of human emotions and using Interaction Ritual Theory this study investigated how pre-service science teachers may be supported in their professional development. It was a multi-method study involving video and audio recordings of teaching episodes supported by interviews and the researcher's diary. Students also registered their perceptions of the emotional climate of their classroom at 3-minute intervals using audience response technology. In this way, emotional events were identified for video analysis. The findings of this study highlighted that the activities pre-service teachers engaged in matter to them. Positive emotional climate was identified in activities involving students' presentations using video clips and models, coteaching, and interactive whole class discussions. Decreases in emotional climate were identified during formal lectures and when unprepared presenters led presentations. Emotions such as frustration and disappointment characterized classes with negative emotional climate. The enabling conditions to sustain a positive emotional climate are identified. Implications for sustaining macro-social policy about Gross National Happiness are considered in light of the climate that develops in science teacher education classes.

Advanced Mirror Technology Development (AMTD) Project: 3.0 Year Status

Science.gov (United States)

Stahl, H. Philip

2015-01-01

Advanced Mirror Technology Development (AMTD) is a funded NASA Strategic Astrophysics Technology project. Begun in 2011, we are in Phase 2 of a multi-year effort. Our objective is to mature towards TRL6 critical technologies needed to produce 4-m or larger flight-qualified UVOIR mirrors by 2018 so that a viable astronomy mission can be considered by the 2020 Decadal Review. The developed technology must enable missions capable of both general astrophysics and ultra-high contrast observations of exoplanets. Just as JWST's architecture was driven by launch vehicle, a future UVOIR mission's architecture (monolithic, segmented or interferometric) will depend on capacities of future launch vehicles (and budget). Since we cannot predict the future, we must prepare for all potential futures. Therefore, we are pursuing multiple technology paths. AMTD uses a science-driven systems engineering approach. We mature technologies required to enable the highest priority science AND result in a high-performance low-cost low-risk system. One of our key accomplishments is that we have derived engineering specifications for advanced normal-incidence monolithic and segmented mirror systems needed to enable both general astrophysics and ultra-high contrast observations of exoplanets missions as a function of potential launch vehicle and its inherent mass and volume constraints. Another key accomplishment is that we have matured our technology by building and testing hardware. To demonstrate stacked core technology, we built a 400 mm thick mirror. Currently, to demonstrate lateral scalability, we are manufacturing a 1.5 meter mirror. To assist in architecture trade studies, the Engineering team develops Structural, Thermal and Optical Performance (STOP) models of candidate mirror assembly systems including substrates, structures, and mechanisms. These models are validated by test of full- and subscale components in relevant thermo-vacuum environments. Specific analyses include: maximum

Two-Mirror Schwarzschild Aplanats: Basic Relations

Science.gov (United States)

Terebizh, V. Yu.

2005-02-01

The theory of aplanatic two-mirror telescopes developed by Karl Schwarzschild in 1905 is shown to lead to a unified description of both prefocal and postfocal systems. The class of surfaces in the ZEMAX optical program has been properly extended to ascertain the image quality in exact Schwarzschild aplanats. A comparison of Schwarzschild aplanats with approximate Ritchey-Chrétien and Gregory-Maksutov aplanatic telescopes reveals a noticeable advantage of the former at the system’s fast focal ratio.

Active Mirror Predictive and Requirements Verification Software (AMP-ReVS)

Science.gov (United States)

Basinger, Scott A.

2012-01-01

This software is designed to predict large active mirror performance at various stages in the fabrication lifecycle of the mirror. It was developed for 1-meter class powered mirrors for astronomical purposes, but is extensible to other geometries. The package accepts finite element model (FEM) inputs and laboratory measured data for large optical-quality mirrors with active figure control. It computes phenomenological contributions to the surface figure error using several built-in optimization techniques. These phenomena include stresses induced in the mirror by the manufacturing process and the support structure, the test procedure, high spatial frequency errors introduced by the polishing process, and other process-dependent deleterious effects due to light-weighting of the mirror. Then, depending on the maturity of the mirror, it either predicts the best surface figure error that the mirror will attain, or it verifies that the requirements for the error sources have been met once the best surface figure error has been measured. The unique feature of this software is that it ties together physical phenomenology with wavefront sensing and control techniques and various optimization methods including convex optimization, Kalman filtering, and quadratic programming to both generate predictive models and to do requirements verification. This software combines three distinct disciplines: wavefront control, predictive models based on FEM, and requirements verification using measured data in a robust, reusable code that is applicable to any large optics for ground and space telescopes. The software also includes state-of-the-art wavefront control algorithms that allow closed-loop performance to be computed. It allows for quantitative trade studies to be performed for optical systems engineering, including computing the best surface figure error under various testing and operating conditions. After the mirror manufacturing process and testing have been completed, the

Effects of Single-Gender Middle School Classes on Science Achievement and Attitude

Science.gov (United States)

Brooks, Tanisha

Many girls continue to achieve below their male counterparts and portray negative attitudes towards science classes. Some school districts are using single-gender education as a way to shrink the gender gap in school achievement and science related attitude. The purpose of this study was to compare achievement and science-related attitudes of 7th grade girls in single-gender education to 7th grade girls in mixed-gender education. The theoretical base for this study included knowledge from brain-based learning and assimilation, accommodation and age factors of Piaget's theory of cognitive development. The 12-week study included 48 7th grade girls, 21 in the single-gender classroom and 14 in each mixed-gender classroom. This quantitative randomized posttest only control group design utilized the TerraNova Science Assessment and the Test of Science Related Attitudes. Analysis of Variance (ANOVA) was used to determine if significant differences existed in the achievement and attitudes of girls in single and mixed-gender science classes. ANOVA analyses revealed that the girls in the single-gender classroom showed a significantly higher achievement level when compared to girls in the mixed-gender classrooms. Results showed no significant difference in attitude between the two groups. The results of this study contribute to social change by raising awareness about gender issues in science achievement and attitude, addressing a deficiency in the single-gender science education literature, and assisting educational systems in decision making to address achievement gaps while moving toward adequate yearly progress and meeting the requirements of the No Child Left Behind Act of 2001.

Space Active Optics: toward optimized correcting mirrors for future large spaceborne observatories

Science.gov (United States)

Laslandes, Marie; Hugot, Emmanuel; Ferrari, Marc; Lemaitre, Gérard; Liotard, Arnaud

2011-10-01

Wave-front correction in optical instruments is often needed, either to compensate Optical Path Differences, off-axis aberrations or mirrors deformations. Active optics techniques are developed to allow efficient corrections with deformable mirrors. In this paper, we will present the conception of particular deformation systems which could be used in space telescopes and instruments in order to improve their performances while allowing relaxing specifications on the global system stability. A first section will be dedicated to the design and performance analysis of an active mirror specifically designed to compensate for aberrations that might appear in future 3m-class space telescopes, due to lightweight primary mirrors, thermal variations or weightless conditions. A second section will be dedicated to a brand new design of active mirror, able to compensate for given combinations of aberrations with a single actuator. If the aberrations to be corrected in an instrument and their evolutions are known in advance, an optimal system geometry can be determined thanks to the elasticity theory and Finite Element Analysis.

AFOCAL SYSTEMS FORMED BY MIRROR OFF-AXIS PARABOLOID

Directory of Open Access Journals (Sweden)

N. K. Artiukhina

2017-01-01

Full Text Available Mirror systems make it possible to reduce device dimensions and its weight while preserving high input aperture and these systems are characterized by a number of other advantages. Their significant disadvantage is a central screening of an entrance pupil that leads to lower image quality. The paper contains description of the investigations on afocal systems formed by eccentrically cut-out mirror paraboloids (off-axis mirrors where aperture diaphragm is displaced in the meridian plane for a defined value and a central field point is located on the optical axis. The canonic Mersenne systems are accepted as base schemas (modules for these compositions. The paper considers two types of such systems: visible increases – Г > 0 and Г < 0. Algorithms for calculation of centered afocal systems with two and four reflections have been written in the paper and the systems are free from spherical aberration, coma, astigmatism when an input pupil is located in superimposed focal planes of all parabolic mirrors. An aberration in curvature image has been additionally corrected in three-mirror quart-parabolic scheme which is a combination of two classical telescopic Mersenne systems. The paper presents schemes and calculation results. Two-mirror schemes with non-screened input pupil have been studied in the paper and in this case all the system remains centered and an aperture diaphragm is decentered for the distance Cm which is commensurable with the diaphragm size. The paper contains description of the investigated afocal schemes with four reflections from off-axis mirror paraboloids, a prepared algorithm for calculation, the obtained formulas for making combination of canonic afocal systems formed by two mirrors. Computer simulation in software environment Opal and Zemax has been carried out in the paper. Basic description has been prepared while using two alternative methods for the class of decentered systems and aberration characteristics and

Electrifying Engagement in Middle School Science Class: Improving Student Interest Through E-textiles

Science.gov (United States)

Tofel-Grehl, Colby; Fields, Deborah; Searle, Kristin; Maahs-Fladung, Cathy; Feldon, David; Gu, Grace; Sun, Chongning

2017-08-01

Most interventions with "maker" technologies take place outside of school or out of core area classrooms. However, intervening in schools holds potential for reaching much larger numbers of students and the opportunity to shift instructional dynamics in classrooms. This paper shares one such intervention where electronic textiles (sewable circuits) were introduced into eighth grade science classes with the intent of exploring possible gains in student learning and motivation, particularly for underrepresented minorities. Using a quasi-experimental design, four classes engaged in a traditional circuitry unit while the other four classes undertook a new e-textile unit. Overall, students in both groups demonstrated significant learning gains on standard test items without significant differences between conditions. Significant differences appeared between groups' attitudes toward science after the units in ways that show increasing interest in science by students in the e-textile unit. In particular, they reported positive identity shifts pertaining to their perceptions of the beliefs of their friends, family, and teacher. Findings and prior research suggest that student-created e-textile designs provide opportunities for connections outside of the classroom with friends and family and may shift students' perceptions of their teacher's beliefs about them more positively.

Einstein's Mirror

Science.gov (United States)

Gjurchinovski, Aleksandar; Skeparovski, Aleksandar

2008-01-01

Reflection of light from a plane mirror in uniform rectilinear motion is a century-old problem, intimately related to the foundations of special relativity. The problem was first investigated by Einstein in his famous 1905 paper by using the Lorentz transformations to switch from the mirror's rest frame to the frame where the mirror moves at a…

Using Mobile Devices to Facilitate Student Questioning in a Large Undergraduate Science Class

Science.gov (United States)

Crompton, Helen; Burgin, Stephen R.; De Paor, Declan G.; Gregory, Kristen

2018-01-01

Asking scientific questions is the first practice of science and engineering listed in the Next Generation Science Standards. However, getting students to ask unsolicited questions in a large class can be difficult. In this qualitative study, undergraduate students sent SMS text messages to the instructor who received them on his mobile phone and…

Critical Science Education in a Suburban High School Chemistry Class

Science.gov (United States)

Ashby, Patrick

To improve students' scientific literacy and their general perceptions of chemistry, I enacted critical chemistry education (CCE) in two "regular level" chemistry classes with a group of 25 students in a suburban, private high school as part of this study. CCE combined the efforts of critical science educators (Fusco & Calabrese Barton, 2001; Gilbert 2013) with the performance expectations of the Next Generation Science Standards (NGSS) (NGSS Lead States, 2013a) to critically transform the traditional chemistry curriculum at this setting. Essentially, CCE engages students in the critical exploration of socially situated chemistry content knowledge and requires them to demonstrate this knowledge through the practices of science. The purpose of this study was to gauge these students development of chemistry content knowledge, chemistry interest, and critical scientific literacy (CSL) as they engaged in CCE. CSL was a construct developed for this study that necessarily combined the National Research Center's (2012) definition of scientific literacy with a critical component. As such, CSL entailed demonstrating content knowledge through the practices of science as well as the ability to critically analyze the intersections between science content and socially relevant issues. A mixed methods, critical ethnographic approach framed the collection of data from open-ended questionnaires, focus group interviews, Likert surveys, pre- and post unit tests, and student artifacts. These data revealed three main findings: (1) students began to develop CSL in specific, significant ways working through the activities of CCE, (2) student participants of CCE developed a comparable level of chemistry content understanding to students who participated in a traditional chemistry curriculum, and (3) CCE developed a group of students' perceptions of interest in chemistry. In addition to being able to teach students discipline specific content knowledge, the implications of this study are

Einstein's Mirror

Science.gov (United States)

Gjurchinovski, Aleksandar; Skeparovski, Aleksandar

2008-10-01

Reflection of light from a plane mirror in uniform rectilinear motion is a century-old problem, intimately related to the foundations of special relativity.1-4 The problem was first investigated by Einstein in his famous 1905 paper by using the Lorentz transformations to switch from the mirror's rest frame to the frame where the mirror moves at a constant velocity.5 Einstein showed an intriguing fact that the usual law of reflection would not hold in the case of a uniformly moving mirror, that is, the angles of incidence and reflection of the light would not equal each other. Later on, it has been shown that the law of reflection at a moving mirror can be obtained in various alternative ways,6-10 but none of them seems suitable for bringing this interesting subject into the high school classroom.

Coherent, Short-Pulse X-ray Generation via Relativistic Flying Mirrors

Directory of Open Access Journals (Sweden)

Masaki Kando

2018-04-01

Full Text Available Coherent, Short X-ray pulses are demanded in material science and biology for the study of micro-structures. Currently, large-sized free-electron lasers are used; however, the available beam lines are limited because of the large construction cost. Here we review a novel method to downsize the system as well as providing fully (spatially and temporally coherent pulses. The method is based on the reflection of coherent laser light by a relativistically moving mirror (flying mirror. Due to the double Doppler effect, the reflected pulses are upshifted in frequency and compressed in time. Such mirrors are formed when an intense short laser pulse excites a strongly nonlinear plasma wave in tenuous plasma. Theory, proof-of-principle, experiments, and possible applications are addressed.

Mirror machine reactors

International Nuclear Information System (INIS)

Carlson, G.A.; Moir, R.W.

1976-01-01

Recent mirror reactor conceptual design studies are described. Considered in detail is the design of ''standard'' Yin-Yang fusion power reactors with classical and enhanced confinement. It is shown that to be economically competitive with estimates for other future energy sources, mirror reactors require a considerable increase in Q, or major design simplifications, or preferably both. These improvements may require a departure from the ''standard'' configuration. Two attractive possibilities, both of which would use much of the same physics and technology as the ''standard'' mirror, are the field reversed mirror and the end-stoppered mirror

TBA-like integral equations from quantized mirror curves

Energy Technology Data Exchange (ETDEWEB)

Okuyama, Kazumi [Department of Physics, Shinshu University,Matsumoto 390-8621 (Japan); Zakany, Szabolcs [Département de Physique Théorique, Université de Genève,Genève, CH-1211 (Switzerland)

2016-03-15

Quantizing the mirror curve of certain toric Calabi-Yau (CY) three-folds leads to a family of trace class operators. The resolvent function of these operators is known to encode topological data of the CY. In this paper, we show that in certain cases, this resolvent function satisfies a system of non-linear integral equations whose structure is very similar to the Thermodynamic Bethe Ansatz (TBA) systems. This can be used to compute spectral traces, both exactly and as a semiclassical expansion. As a main example, we consider the system related to the quantized mirror curve of local ℙ{sup 2}. According to a recent proposal, the traces of this operator are determined by the refined BPS indices of the underlying CY. We use our non-linear integral equations to test that proposal.

TBA-like integral equations from quantized mirror curves

Science.gov (United States)

Okuyama, Kazumi; Zakany, Szabolcs

2016-03-01

Quantizing the mirror curve of certain toric Calabi-Yau (CY) three-folds leads to a family of trace class operators. The resolvent function of these operators is known to encode topological data of the CY. In this paper, we show that in certain cases, this resolvent function satisfies a system of non-linear integral equations whose structure is very similar to the Thermodynamic Bethe Ansatz (TBA) systems. This can be used to compute spectral traces, both exactly and as a semiclassical expansion. As a main example, we consider the system related to the quantized mirror curve of local P2. According to a recent proposal, the traces of this operator are determined by the refined BPS indices of the underlying CY. We use our non-linear integral equations to test that proposal.

Agency Amidst Formidable Structures: How Girls Perform Gender in Science Class

Science.gov (United States)

Carlone, Heidi B.; Johnson, Angela; Scott, Catherine M.

2015-01-01

Larger social structures such as race, class, gender, and sexuality and classroom structures like narrowly defined participation practices constrain individuals' agency to engage in untroubled and sustained science identity work. This article explores the central dilemma of attending to structure and agency in settings where inequities are…

Understanding Korean Transnational Girls in High School Science Classes: Beyond the Model Minority Stereotype

Science.gov (United States)

Ryu, Minjung

2015-01-01

This study examines six Korean transnational girls enrolled in two advanced placement (AP) biology classes to understand their experiences in science classrooms at the intersection of race, language, and gender. Confronting the model minority stereotype for Asian students, which is particularly salient in science, technology, engineering, and…

Tandem mirror and field-reversed mirror experiments

Energy Technology Data Exchange (ETDEWEB)

Coensgen, F.H.; Simonen, T.C.; Turner, W.C.

1979-08-21

This paper is largely devoted to tandem mirror and field-reversed mirror experiments at the Lawrence Livermore Laboratory (LLL), and briefly summarizes results of experiments in which field-reversal has been achieved. In the tandem experiment, high-energy, high-density plasmas (nearly identical to 2XIIB plasmas) are located at each end of a solenoid where plasma ions are electrostatically confined by the high positive poentials arising in the end plug plasma. End plug ions are magnetically confined, and electrons are electrostatically confined by the overall positive potential of the system. The field-reversed mirror reactor consists of several small field-reversed mirror plasmas linked together for economic reasons. In the LLL Beta II experiment, generation of a field-reversed plasma ring will be investigated using a high-energy plasma gun with a transverse radial magnetic field. This plasma will be further heated and sustained by injection of intense, high-energy neutral beams.

Thin Mirror Shaping Technology for High-Throughput X-ray Telescopes

Science.gov (United States)

Schattenburg, Mark

This proposal is submitted to the NASA Research Opportunities in Space and Earth Sciences program (ROSES-2012) in response to NASA Research Announcement NNH12ZDA001N- APRA. It is targeted to the Astronomy and Astrophysics Research and Analysis (APRA) program element under the Supporting Technology category. Powerful x-ray telescope mirrors are critical components of a raft of small-to-large mission concepts under consideration by NASA. The science questions addressed by these missions have certainly never been more compelling and the need to fulfill NASA s core missions of exploring the universe and strengthening our nation s technology base has never been greater. Unfortunately, budgetary constraints are driving NASA to consider the cost/benefit and risk factors of new missions more carefully than ever. New technology for producing x-ray telescopes with increased resolution and collecting area, while holding down cost, are key to meeting these goals and sustaining a thriving high-energy astrophysics enterprise in the US. We propose to develop advanced technology which will lead to thin-shell x-ray telescope mirrors rivaling the Chandra x-ray telescope in spatial resolution but with 10-100X larger area all at significantly reduced weight, risk and cost. The proposed effort builds on previous research at MIT and complements NASA-supported research at other institutions. We are currently pursuing two thin-mirror technology development tracks which we propose to extend and accelerate with NASA support. The first research track utilizes rapidly-maturing thermal glass slumping technology which uses porous ceramic air-bearing mandrels to shape glass mirrors without touching, thus avoiding surface-induced mid-range spatial frequency ripples. A second research track seeks to remove any remaining mid- to long-range errors in mirrors by using scanning ion-beam implant to impart small, highly deterministic and very stable amounts of stress into thin glass, utilizing local

Mirror symmetry

CERN Document Server

Voisin, Claire

1999-01-01

This is the English translation of Professor Voisin's book reflecting the discovery of the mirror symmetry phenomenon. The first chapter is devoted to the geometry of Calabi-Yau manifolds, and the second describes, as motivation, the ideas from quantum field theory that led to the discovery of mirror symmetry. The other chapters deal with more specialized aspects of the subject: the work of Candelas, de la Ossa, Greene, and Parkes, based on the fact that under the mirror symmetry hypothesis, the variation of Hodge structure of a Calabi-Yau threefold determines the Gromov-Witten invariants of its mirror; Batyrev's construction, which exhibits the mirror symmetry phenomenon between hypersurfaces of toric Fano varieties, after a combinatorial classification of the latter; the mathematical construction of the Gromov-Witten potential, and the proof of its crucial property (that it satisfies the WDVV equation), which makes it possible to construct a flat connection underlying a variation of Hodge structure in the ...

Technology of mirror machines: LLL facilities for magnetic mirror fusion experiments

International Nuclear Information System (INIS)

Batzer, T.H.

1977-01-01

Significant progress in plasma confinement and temperature has been achieved in the 2XIIB facility at Livermore. These encouraging results, and their theoretical corroboration, have provided a firm basis for the design of a new generation of magnetic mirror experiments, adding support to the mirror concept of a fusion reactor. Two new mirror experiments have been proposed to succeed the currently operating 2XIIB facility. The first of these called TMX (Tandem Mirror Experiment) has been approved and is currently under construction. TMX is designed to utilize the intrinsic positive plasma potential of two strong, and relatively small, minimum B mirror cells to enhance the confinement of a much larger, magnetically weaker, centrally-located mirror cell. The second facility, MFTF (Mirror Fusion Test Facility), is currently in preliminary design with line item approval anticipated for FY 78. MFTF is designed primarily to exploit the experimental and theoretical results derived from 2XIIB. Beyond that, MFTF will develop the technology for the transition from the present small mirror experiments to large steady-state devices such as the mirror FERF/FTR. The sheer magnitude of the plasma volume, magnetic field, neutral beam power, and vacuum pumping capacity, particularly in the case of MFTF, has placed new and exciting demands on engineering technology. An engineering overview of MFTF, TMX, and associated MFE activities at Livermore will be presented

[Motion control of moving mirror based on fixed-mirror adjustment in FTIR spectrometer].

Science.gov (United States)

Li, Zhong-bing; Xu, Xian-ze; Le, Yi; Xu, Feng-qiu; Li, Jun-wei

2012-08-01

The performance of the uniform motion of the moving mirror, which is the only constant motion part in FTIR spectrometer, and the performance of the alignment of the fixed mirror play a key role in FTIR spectrometer, and affect the interference effect and the quality of the spectrogram and may restrict the precision and resolution of the instrument directly. The present article focuses on the research on the uniform motion of the moving mirror and the alignment of the fixed mirror. In order to improve the FTIR spectrometer, the maglev support system was designed for the moving mirror and the phase detection technology was adopted to adjust the tilt angle between the moving mirror and the fixed mirror. This paper also introduces an improved fuzzy PID control algorithm to get the accurate speed of the moving mirror and realize the control strategy from both hardware design and algorithm. The results show that the development of the moving mirror motion control system gets sufficient accuracy and real-time, which can ensure the uniform motion of the moving mirror and the alignment of the fixed mirror.

Advanced X-Ray Telescope Mirrors Provide Sharpest Focus Ever

Science.gov (United States)

1997-03-01

Performing beyond expectations, the high- resolution mirrors for NASA's most powerful orbiting X-ray telescope have successfully completed initial testing at Marshall Space Flight Center's X-ray Calibration Facility, Huntsville, AL. "We have the first ground test images ever generated by the telescope's mirror assembly, and they are as good as -- or better than -- expected," said Dr. Martin Weisskopf, Marshall's chief scientist for NASA's Advanced X-ray Astrophysics Facility (AXAF). The mirror assembly, four pairs of precisely shaped and aligned cylindrical mirrors, will form the heart of NASA's third great observatory. The X-ray telescope produces an image by directing incoming X-rays to detectors at a focal point some 30 feet beyond the telescope's mirrors. The greater the percentage of X-rays brought to focus and the smaller the size of the focal spot, the sharper the image. Tests show that on orbit, the mirror assembly of the Advanced X-ray Astrophysics Facility will be able to focus approximately 70 percent of X-rays from a source to a spot less than one-half arc second in radius. The telescope's resolution is equivalent to being able to read the text of a newspaper from half a mile away. "The telescope's focus is very clear, very sharp," said Weisskopf. "It will be able to show us details of very distant sources that we know are out there, but haven't been able to see clearly." In comparison, previous X-ray telescopes -- Einstein and Rosat -- were only capable of focusing X- rays to five arc seconds. The Advanced X-ray Telescope's resolving power is ten times greater. "Images from the new telescope will allow us to make major advances toward understanding how exploding stars create and disperse many of the elements necessary for new solar systems and for life itself," said Dr. Harvey Tananbaum, director of the Advanced X- ray Astrophysics Facility Science Center at the Smithsonian Astrophysical Observatory, in Cambridge, MA -- responsible for the telescope

[The mirror neuron system in motor and sensory rehabilitation].

Science.gov (United States)

Oouchida, Yutaka; Izumi, Shinichi

2014-06-01

The discovery of the mirror neuron system has dramatically changed the study of motor control in neuroscience. The mirror neuron system provides a conceptual framework covering the aspects of motor as well as sensory functions in motor control. Previous studies of motor control can be classified as studies of motor or sensory functions, and these two classes of studies appear to have advanced independently. In rehabilitation requiring motor learning, such as relearning movement after limb paresis, however, sensory information of feedback for motor output as well as motor command are essential. During rehabilitation from chronic pain, motor exercise is one of the most effective treatments for pain caused by dysfunction in the sensory system. In rehabilitation where total intervention unifying the motor and sensory aspects of motor control is important, learning through imitation, which is associated with the mirror neuron system can be effective and suitable. In this paper, we introduce the clinical applications of imitated movement in rehabilitation from motor impairment after brain damage and phantom limb pain after limb amputation.

The challenge of developing thin mirror shells for future x-ray telescopes

Science.gov (United States)

Döhring, Thorsten; Stollenwerk, Manfred; Gong, Qingqing; Proserpio, Laura; Winter, Anita; Friedrich, Peter

2015-09-01

Previously used mirror technologies are not able to fulfil the requirements of future X-ray telescopes due to challenging requests from the scientific community. Consequently new technical approaches for X-ray mirror production are under development. In Europe the technical baseline for the planned X-ray observatory ATHENA is the radical new approach of silicon pore optics. NASÁs recently launched NuSTAR mission uses segmented mirrors shells made from thin bended glasses, successfully demonstrating the feasibility of the glass forming technology for X-ray mirrors. For risk mitigation also in Europe the hot slumping of thin glasses is being developed as an alternative technology for lightweight X-ray telescopes. The high precision mirror manufacturing requires challenging technical developments; several design trades and trend-setting decisions need to be made and are discussed within this paper. Some new technical and economic aspects of the intended glass mirror serial production are also studied within the recently started interdisciplinary project INTRAAST, an acronym for "industry transfer of astronomical mirror technologies". The goal of the project, embedded in a cooperation of the Max-Planck-Institute for extraterrestrial Physics and the University of Applied Sciences Aschaffenburg, is to master the challenge of producing thin mirror shells for future X-ray telescopes. As a first project task the development of low stress coatings for thin glass mirror substrates have been started, the corresponding technical approach and first results are presented.

MHD-Stabilization of Axisymmetric Mirror Systems Using Pulsed ECRH

International Nuclear Information System (INIS)

Post, R.F.

2010-01-01

This paper, part of a continuing study of means for the stabilization of MHD interchange modes in axisymmertric mirror-based plasma confinement systems, is aimed at a preliminary look at a technique that would employ a train of plasma pressure pulses produced by ECRH to accomplish the stabilization. The purpose of using sequentially pulsed ECRH rather than continuous-wave ECRH is to facilitate the localization of the heated-electron plasma pulses in regions of the magnetic field with a strong positive field-line curvature, e. g. in the 'expander' region of the mirror magnetic field, outside the outermost mirror, or in other regions of the field with positive field-line curvature. The technique proposed, of the class known as 'dynamic stabilization,' relies on the time-averaged effect of plasma pressure pulses generated in regions of positive field-line curvature to overcome the destabilizing effect of plasma pressure in regions of negative field-line curvature within the confinement region. As will also be discussed in the paper, the plasma pulses, when produced in regions of the confining having a negative gradient, create transient electric potentials of ambipolar origin, an effect that was studied in 1964 in The PLEIDE experiment in France. These electric fields preserve the localization of the hot-electron plasma pulses for a time determined by ion inertia. It is suggested that it may be possible to use this result of pulsed ECRH not only to help to stabilize the plasma but also to help plug mirror losses in a manner similar to that employed in the Tandem Mirror.

The function of mirror neurons in the learning process

Directory of Open Access Journals (Sweden)

Mara Daniel

2017-01-01

Full Text Available In the last years, Neurosciences have developed very much, being elaborated many important theories scientific research in the field. The main goal of neuroscience is to understand how groups of neurons interact to create the behavior. Neuroscientists studying the action of molecules, genes and cells. It also explores the complex interactions involved in motion perception, thoughts, emotions and learning. Brick fundamental nervous system is the nerve cell, neuron. Neurons exchange information by sending electrical signals and chemical through connections called synapses. Discovered by a group of Italian researchers from the University of Parma, neurons - mirror are a special class of nerve cells played an important role in the direct knowledge, automatic and unconscious environment. These cortical neurons are activated not only when an action is fulfilled, but when we see how the same action is performed by someone else, they represent neural mechanism by which the actions, intentions and emotions of others can be understood automatically. In childhood neurons - mirror are extremely important. Thanks to them we learned a lot in the early years: smile, to ask for help and, in fact, all the behaviors and family and group norms. People learn by what they see and sense the others. Neurons - mirror are important to understanding the actions and intentions of other people and learn new skills through mirror image. They are involved in planning and controlling actions, abstract thinking and memory. If a child observes an action, neurons - mirror is activated and forming new neural pathways as if even he takes that action. Efficient activity of mirror neurons leads to good development in all areas at a higher emotional intelligence and the ability to empathize with others.

Mirror and (absence of) counter-mirror responses to action sounds measured with TMS.

Science.gov (United States)

Ticini, Luca F; Schütz-Bosbach, Simone; Waszak, Florian

2017-11-01

To what extent is the mirror neuron mechanism malleable to experience? The answer to this question can help characterising its ontogeny and its role in social cognition. Some suggest that it develops through sensorimotor associations congruent with our own actions. Others argue for its extreme volatility that will encode any sensorimotor association in the environment. Here, we added to this debate by exploring the effects of short goal-directed 'mirror' and 'counter-mirror' trainings (a 'mirror' training is defined as the first type of training encountered by the participants) on human auditory mirror motor-evoked potentials (MEPs). We recorded MEPs in response to two tones void of previous motor meaning, before and after mirror and counter-mirror trainings in which participants generated two tones of different pitch by performing free-choice button presses. The results showed that mirror MEPs, once established, were protected against an equivalent counter-mirror experience: they became manifest very rapidly and the same number of training trials that lead to the initial association did not suffice to reverse the MEP pattern. This steadiness of the association argues that, by serving direct-matching purposes, the mirror mechanism is a good solution for social cognition. © The Author (2017). Published by Oxford University Press.

Trends in gender diversity American soil science classes: 2004-2005 to 2013-2014 academic years

Science.gov (United States)

Lindbo, David L.; Brevik, Eric C.; Vaughan, Karen L.; Parikh, Sanjai J.; Dilliver, Holly; Steffan, Joshua J.; Weindorf, David; McDaniel, Paul; Mbila, Monday; Edinger-Marshall, Susan; Thomas, Pamela

2017-04-01

A diverse workforce has been viewed for a long time as a healthy workforce. Traditionally however Soil Science has been seen as a male dominated field. The total number of female students enrolled showed increasing trends in all classes investigated during this study, but the percentage of female students showed a decline when analyzed by total students enrolled and also declined in four of the seven individual classes investigated. While both total enrollment and female enrollment increased during the study, male enrollment increased more rapidly than female enrollment. Soil biology/microbiology classes had a trend of more than 45% female enrollment throughout the study period, but many classes had less than 40% female enrollment, especially after the 2008-2009 academic year, and some hovered around only 35% female enrollment. The percentage of female soil science students had increased in the USA and Canada from 1992 to 2004 (Baveye et al., 2006) and Miller (2011) reported an increase in the number of female students at Iowa State University in the early 2000s. Therefore, the decrease in percentage of female soil science students found in our study was disappointing, even though absolute numbers of female students increased. It appears there is still a need to find ways to better market soil science coursework to female students. One possible way to accomplish this is to take advantage of the fact that many schools are now focusing efforts on STEM training specifically for females in grades 5-12, whereby science projects, after school programs, and mentorship can substantively influence females to pursue science-based fields in college. Another possibility is to promote the trends in female employment. As an example female employment within the Soil Science Division of the USDA-NRCS has increased over the same period. It should also be noted that the number of females in leadership roles has also increased. As a profession, soil science should look to take

X-ray beam-shaping via deformable mirrors: surface profile and point spread function computation for Gaussian beams using physical optics.

Science.gov (United States)

Spiga, D

2018-01-01

X-ray mirrors with high focusing performances are commonly used in different sectors of science, such as X-ray astronomy, medical imaging and synchrotron/free-electron laser beamlines. While deformations of the mirror profile may cause degradation of the focus sharpness, a deliberate deformation of the mirror can be made to endow the focus with a desired size and distribution, via piezo actuators. The resulting profile can be characterized with suitable metrology tools and correlated with the expected optical quality via a wavefront propagation code or, sometimes, predicted using geometric optics. In the latter case and for the special class of profile deformations with monotonically increasing derivative, i.e. concave upwards, the point spread function (PSF) can even be predicted analytically. Moreover, under these assumptions, the relation can also be reversed: from the desired PSF the required profile deformation can be computed analytically, avoiding the use of trial-and-error search codes. However, the computation has been so far limited to geometric optics, which entailed some limitations: for example, mirror diffraction effects and the size of the coherent X-ray source were not considered. In this paper, the beam-shaping formalism in the framework of physical optics is reviewed, in the limit of small light wavelengths and in the case of Gaussian intensity wavefronts. Some examples of shaped profiles are also shown, aiming at turning a Gaussian intensity distribution into a top-hat one, and checks of the shaping performances computing the at-wavelength PSF by means of the WISE code are made.

Scientist Spotlight Homework Assignments Shift Students’ Stereotypes of Scientists and Enhance Science Identity in a Diverse Introductory Science Class

Science.gov (United States)

Schinske, Jeffrey N.; Perkins, Heather; Snyder, Amanda; Wyer, Mary

2016-01-01

Research into science identity, stereotype threat, and possible selves suggests a lack of diverse representations of scientists could impede traditionally underserved students from persisting and succeeding in science. We evaluated a series of metacognitive homework assignments (“Scientist Spotlights”) that featured counterstereotypical examples of scientists in an introductory biology class at a diverse community college. Scientist Spotlights additionally served as tools for content coverage, as scientists were selected to match topics covered each week. We analyzed beginning- and end-of-course essays completed by students during each of five courses with Scientist Spotlights and two courses with equivalent homework assignments that lacked connections to the stories of diverse scientists. Students completing Scientist Spotlights shifted toward counterstereotypical descriptions of scientists and conveyed an enhanced ability to personally relate to scientists following the intervention. Longitudinal data suggested these shifts were maintained 6 months after the completion of the course. Analyses further uncovered correlations between these shifts, interest in science, and course grades. As Scientist Spotlights require very little class time and complement existing curricula, they represent a promising tool for enhancing science identity, shifting stereotypes, and connecting content to issues of equity and diversity in a broad range of STEM classrooms. PMID:27587856

U. S. Mirror Program

International Nuclear Information System (INIS)

Fowler, T.K.

1978-01-01

The mirror approach is now the principal alternate to the tokamak in the U.S. magnetic fusion energy program. The program is now focused on two new concepts that can obtain high values of Q, defined as the ratio of fusion power output to the neutral beam power injected to sustain the reaction. These are the tandem mirror and field reversed mirror concepts. Theoretically both concepts should be able to attain Q = 5 or more, as compared with Q approximately 1 in previous mirror designs. Success with either or both of these approaches would point the way toward fusion power plants with many attractive features. The linear geometry of mirror systems offers a distinct alternative to the toroidal tokamak. As a direct consequence of this difference in geometry, it is generally possible to build mirror systems in smaller units of modular construction that can probably be made to operate in steady-state. During the next 5 years the main mirror facilities in the U.S. will be the 2XIIB (renamed Beta II); a tandem mirror experiment caled TMX; and the Mirror Fusion Test Facility (MFTF) scheduled to be completed in 1981 at a cost of $94 million. As a background for discussing this program and mirror reactor concepts in later lectures, the current status of mirror physics will be reviewed by comparing theory and experimental data in four critical areas. These are adiabatic confinement of individual ions, electron heat losses out of the ends of the machine, the achievement of beta values of order unity; and stabilization of ''loss cone'' modes

Impulsive moving mirror model and the stability of Schroedinger equation with impulse effect in a Banach space

International Nuclear Information System (INIS)

Kostadinov, S.I.; Petrov, G.

1992-01-01

From a special class of systems has been used a Schroedinger equation with impulse effect in Minkowski space field theory with time dependent boundary conditions, i.e. those of moving mirrors. The field theoretical approach for studying the properties of the vacuum starts from an analysis of the behaviour of local field quantities in Minkowski space with uniformly moving mirrors. For the impulsive moving mirror model is the real process of interaction between the quantum field and the external mirror a subject to disturbances in its evolution acting in time very short compared with the entire duration of the process. So the stability of the solution of the Schroedinger evolution equation for the process in the stability of the vacuum of Casimir. 8 refs

Development of iridium coated x-ray mirrors for astronomical applications

Science.gov (United States)

Döhring, Thorsten; Probst, Anne-Catherine; Emmerich, Florian; Stollenwerk, Manfred; Stehlíková, Veronika; Friedrich, Peter; Damm, Christine

2017-08-01

Future space-based X-ray observatories need to be very lightweight for launcher mass constraints. Therefore they will use a reduced mirror thickness, which results in the additional requirement of low coating stress to avoid deformation of the initial precisely shaped mirror substrates. Due to their excellent reflection properties iridium coatings are sometimes applied for grazing incidence mirrors in astronomical X-ray telescopes. At Aschaffenburg University of Applied Sciences the coating of thin iridium films by an RF-magnetron sputtering technique is under development. The work is embedded in collaborations with the Max-Planck-Institute for Extraterrestrial Physics in Germany, the Czech Technical University in Prague, the Osservatorio Astronomico di Brera in Italy, the German Leibniz Institute for Solid State and Materials Research in Dresden, and the French Institute Fresnel. Sputtering with different parameters leads to iridium films with different properties. The current work is focused on the microstructure of the iridium coatings to study the influence of the substrate and of the argon gas pressure on the thin film growing process. Correlations between coating density, surface micro-roughness, the crystalline structure of the iridium layers, and the expected reflectivity of the X-ray mirror as well as coating stress effects are presented and discussed. The final goal of the project is to integrate the produced prototype mirrors into an X-ray telescope module. On a longer timescale measurements of the mirror modules optical performance are planned at the X-ray test facility PANTER.

Investigating Optimal Learning Moments in U.S. and Finnish Science Classes

Science.gov (United States)

Schneider, Barbara; Krajcik, Joseph; Lavonen, Jari; Salmela-Aro, Katariina; Broda, Michael; Spicer, Justina; Bruner, Justin; Moeller, Julia; Linnansaari, Janna; Juuti, Kalle; Viljaranta, Jaana

2016-01-01

This study explores how often students are engaged in their science classes and their affective states during these times, using an innovative methodology that records these experiences "in situ". Sampling a subset of high schools in the U.S. and Finland, we collected over 7,000 momentary responses from 344 students over the course of a…

Reflective mirrors: perspective-taking in autoscopic phenomena.

Science.gov (United States)

Brugger, Peter

2002-08-01

''Autoscopic phenomena refer to different illusory reduplications of one's own body and self. This article proposes a phenomenological differentiation of autoscopic reduplication into three distinct classes, i.e., autoscopic hallucinations, heautoscopy, and out-of-body experiences (OBEs). Published cases are analysed with special emphasis on the subject's point of view from which the reduplication is observed. In an autoscopic hallucination the observer's perspective is clearly body-centred, and the visual image of one's own body appears as a mirror reversal. Heautoscopy (i.e., the encounter with an alter ego or doppelgänger), is defined as a reduplication not only of bodily appearance, but also of aspects of one's psychological self. The observer's perspective may alternate between egocentric and ''alter-ego-centred''. As a consequence of the projection of bodily feelings into the doppelgänger (implying a mental rotation of one's own body along the vertical axis), original and reduplicated bodies are not mirror images of one another. This also holds for OBEs, where one's self is not reduplicated but appears to be completely dissociated from the body and observing it from a location in extracorporeal space. It is argued that perspective-taking in a spatial sense may be meaningfully related to perspective-taking in a psychological sense. The mirror in the autoscopic hallucination is a ''cognitively nonreflective mirror'' (Jean Cocteau), both spatially and psychologically. The reflective abilities of the heautoscopic mirror are better developed, yet frequent shifts in the observer's spatial perspective render the nature of psychological interactions between self and alter ego highly unpredictable. The doppelgänger may serve a transitivistic (i.e., own suffering is transferred to the alter ego) or aggressive function when this behaviour is directed against a patient. The mirror in an OBE is always reflective: It allows the self to view both space and one

Mirror symmetry in the presence of branes

Energy Technology Data Exchange (ETDEWEB)

Mertens, Adrian

2011-10-11

This work deals with mirror symmetry for N=1 compactifications on compact Calabi-Yau threefolds with branes. The mayor tool is a combined deformation space for the Calabi-Yau and a hypersurface within it. Periods of this deformation space contain information about B-type branes within the hypersurface in addition to the usual closed string data. To study these periods we generalize techniques used in closed string mirror symmetry. We derive the Picard-Fuchs system and encode the information in extended toric polytopes. Solutions of the Picard-Fuchs equations give superpotentials for certain brane configurations. This is an efficient way to calculate superpotentials. The deformations we consider are massive for all branes with non trivial superpotential. Depending on a choice of a family of hypersurfaces, the superpotential of the effective low energy theory depends on different massive fields. A priori there is no reason for these fields to be lighter then other fields that are not included. We find however examples where the superpotential is nearly at. In these examples we use the Gauss-Manin connection on the combined deformation space to define an open string mirror map. We find instanton generated superpotentials of A-type branes. This gives predictions for Ooguri-Vafa invariants counting holomorphic disks that end on a Lagrangian brane on the Quintic. A second class of examples does not have preferred nearly massless deformations and different families of hypersurfaces can be used to calculate the same on-shell superpotential. We calculate examples of superpotentials for branes in Calabi-Yau manifolds with several moduli. The on-shell superpotentials are mapped to the mirror A-model to study the instanton expansion and to obtain predictions for disk invariants. The combined deformation spaces are equivalent to the quantum corrected Kaehler deformation spaces of certain non compact Calabi-Yau fourfolds. These fourfolds are fibrations of Calabi-Yau threefolds

Mirror symmetry in the presence of branes

International Nuclear Information System (INIS)

Mertens, Adrian

2011-01-01

This work deals with mirror symmetry for N=1 compactifications on compact Calabi-Yau threefolds with branes. The mayor tool is a combined deformation space for the Calabi-Yau and a hypersurface within it. Periods of this deformation space contain information about B-type branes within the hypersurface in addition to the usual closed string data. To study these periods we generalize techniques used in closed string mirror symmetry. We derive the Picard-Fuchs system and encode the information in extended toric polytopes. Solutions of the Picard-Fuchs equations give superpotentials for certain brane configurations. This is an efficient way to calculate superpotentials. The deformations we consider are massive for all branes with non trivial superpotential. Depending on a choice of a family of hypersurfaces, the superpotential of the effective low energy theory depends on different massive fields. A priori there is no reason for these fields to be lighter then other fields that are not included. We find however examples where the superpotential is nearly at. In these examples we use the Gauss-Manin connection on the combined deformation space to define an open string mirror map. We find instanton generated superpotentials of A-type branes. This gives predictions for Ooguri-Vafa invariants counting holomorphic disks that end on a Lagrangian brane on the Quintic. A second class of examples does not have preferred nearly massless deformations and different families of hypersurfaces can be used to calculate the same on-shell superpotential. We calculate examples of superpotentials for branes in Calabi-Yau manifolds with several moduli. The on-shell superpotentials are mapped to the mirror A-model to study the instanton expansion and to obtain predictions for disk invariants. The combined deformation spaces are equivalent to the quantum corrected Kaehler deformation spaces of certain non compact Calabi-Yau fourfolds. These fourfolds are fibrations of Calabi-Yau threefolds

An integrative review of in-class activities that enable active learning in college science classroom settings

Science.gov (United States)

Arthurs, Leilani A.; Kreager, Bailey Zo

2017-10-01

Engaging students in active learning is linked to positive learning outcomes. This study aims to synthesise the peer-reviewed literature about 'active learning' in college science classroom settings. Using the methodology of an integrative literature review, 337 articles archived in the Educational Resources Information Center (ERIC) are examined. Four categories of in-class activities emerge: (i) individual non-polling activities, (ii) in-class polling activities, (iii) whole-class discussion or activities, and (iv) in-class group activities. Examining the collection of identified in-class activities through the lens of a theoretical framework informed by constructivism and social interdependence theory, we synthesise the reviewed literature to propose the active learning strategies (ALSs) model and the instructional decisions to enable active learning (IDEAL) theory. The ALS model characterises in-class activities in terms of the degrees to which they are designed to promote (i) peer interaction and (ii) social interdependence. The IDEAL theory includes the ALS model and provides a framework for conceptualising different levels of the general concept 'active learning' and how these levels connect to instructional decision-making about using in-class activities. The proposed ALS model and IDEAL theory can be utilised to inform instructional decision-making and future research about active learning in college science courses.

MSFC Test Results for Selected Mirrors: Brush-Wellman/Goodrich 0.5 meter Joined-Beryllium Mirror; IABG 0.5 meter C/SiC Mirror; Xinetics 0.5 meter SiC Mirror; and Kodak 0.23 meter SiO2 Mirror

Science.gov (United States)

Hadaway, James; Blackwell, Lisa; Matthews, Gary; Eng, Ron; Stahl, Phil; Hraba, John; Thornton, Gary

2002-01-01

The results of cryo tests performed at the XRCF on the above mirrors will be presented. Each mirror was tested from room-temperature to around 30 K. The first three were tested together on a 3-mirror stand in the large chamber using the PhaseCam interferometer, while the Kodak mirror was tested in the small chamber using the EPI interferometer.

Plasma mirrors for ultrahigh-intensity optics

Energy Technology Data Exchange (ETDEWEB)

Thaury, C; Quere, F; Levy, A; Ceccotti, T; Monot, P; Bougeard, M; Reau, F; D' Oliveira, P; Martin, PH [CEA, DSM, DRECAM, Serv Photons Atomes and Mol, F-91191 Gif Sur Yvette, (France); Geindre, J P; Audebert, P [Ecole Polytech, CNRS, Lab Utilisat Lasers Inst, F-91128 Palaiseau, (France); Marjoribanks, R [Univ Toronto, Dept Phys, Toronto, ON M5S 1A7, (Canada); Marjoribanks, R [Univ Toronto, Inst Opt Sci, Toronto, ON M5S 1A7, (Canada)

2007-07-01

Specular reflection is one of the most fundamental processes of optics. At moderate light intensities generated by conventional light sources this process is well understood. But at those capable of being produced by modern ultrahigh-intensity lasers, many new and potentially useful phenomena arise. When a pulse from such a laser hits an optically polished surface, it generates a dense plasma that itself acts as a mirror, known as a plasma mirror (PM). PMs do not just reflect the remainder of the incident beam, but can act as active optical elements. Using a set of three consecutive PMs in different regimes, we significantly improve the temporal contrast of femtosecond pulses, and demonstrate that high-order harmonics of the laser frequency can be generated through two distinct mechanisms. A better understanding of these processes should aid the development of laser-driven atto-second sources for use in fields from materials science to molecular biology. (authors)

Plasma mirrors for ultrahigh-intensity optics

International Nuclear Information System (INIS)

Thaury, C.; Quere, F.; Levy, A.; Ceccotti, T.; Monot, P.; Bougeard, M.; Reau, F.; D'Oliveira, P.; Martin, PH.; Geindre, J.P.; Audebert, P.; Marjoribanks, R.; Marjoribanks, R.

2007-01-01

Specular reflection is one of the most fundamental processes of optics. At moderate light intensities generated by conventional light sources this process is well understood. But at those capable of being produced by modern ultrahigh-intensity lasers, many new and potentially useful phenomena arise. When a pulse from such a laser hits an optically polished surface, it generates a dense plasma that itself acts as a mirror, known as a plasma mirror (PM). PMs do not just reflect the remainder of the incident beam, but can act as active optical elements. Using a set of three consecutive PMs in different regimes, we significantly improve the temporal contrast of femtosecond pulses, and demonstrate that high-order harmonics of the laser frequency can be generated through two distinct mechanisms. A better understanding of these processes should aid the development of laser-driven atto-second sources for use in fields from materials science to molecular biology. (authors)

The Axisymmetric Tandem Mirror: A Magnetic Mirror Concept Game Changer Magnet Mirror Status Study Group

International Nuclear Information System (INIS)

Simonen, T.; Cohen, R.; Correll, D.; Fowler, K.; Post, D.; Berk, H.; Horton, W.; Hooper, E.B.; Fisch, N.; Hassam, A.; Baldwin, D.; Pearlstein, D.; Logan, G.; Turner, B.; Moir, R.; Molvik, A.; Ryutov, D.; Ivanov, A.A; Kesner, J.; Cohen, B.; McLean, H.; Tamano, T.; Tang, X.Z.; Imai, T.

2008-01-01

Experimental results, theory and innovative ideas now point with increased confidence to the possibility of a Gas Dynamic Trap (GDT) neutron source which would be on the path to an attractively simple Axisymmetric Tandem Mirror (ATM) power plant. Although magnetic mirror research was terminated in the US 20 years ago, experiments continued in Japan (Gamma 10) and Russia (GDT), with a very small US effort. This research has now yielded data, increased understanding, and generated ideas resulting in the new concepts described here. Early mirror research was carried out with circular axisymmetric magnets. These plasmas were MHD unstable due to the unfavorable magnetic curvature near the mid-plane. Then the minimum-B concept emerged in which the field line curvature was everywhere favorable and the plasma was situated in a MHD stable magnetic well (70% average beta in 2XII-B). The Ioffe-bar or baseball-coil became the standard for over 40 years. In the 1980's, driven by success with minimum-B stabilization and the control of ion cyclotron instabilities in PR6 and 2XII-B, mirrors were viewed as a potentially attractive concept with near-term advantages as a lower Q neutron source for applications such as a hybrid fission fuel factory or toxic waste burner. However there are down sides to the minimum-B geometry: coil construction is complex; restraining magnetic forces limit field strength and mirror ratios. Furthermore, the magnetic field lines have geodesic curvature which introduces resonant and neoclassical radial transport as observed in early tandem mirror experiments. So what now leads us to think that simple axisymmetric mirror plasmas can be stable? The Russian GDT experiment achieves on-axis 60% beta by peaking of the kinetic plasma pressure near the mirror throat (where the curvature is favorable) to counter-balance the average unfavorable mid-plane curvature. Then a modest augmentation of plasma pressure in the expander results in stability. The GDT

The Axisymmetric Tandem Mirror: A Magnetic Mirror Concept Game Changer Magnet Mirror Status Study Group

Energy Technology Data Exchange (ETDEWEB)

Simonen, T; Cohen, R; Correll, D; Fowler, K; Post, D; Berk, H; Horton, W; Hooper, E B; Fisch, N; Hassam, A; Baldwin, D; Pearlstein, D; Logan, G; Turner, B; Moir, R; Molvik, A; Ryutov, D; Ivanov, A A; Kesner, J; Cohen, B; McLean, H; Tamano, T; Tang, X Z; Imai, T

2008-10-24

Experimental results, theory and innovative ideas now point with increased confidence to the possibility of a Gas Dynamic Trap (GDT) neutron source which would be on the path to an attractively simple Axisymmetric Tandem Mirror (ATM) power plant. Although magnetic mirror research was terminated in the US 20 years ago, experiments continued in Japan (Gamma 10) and Russia (GDT), with a very small US effort. This research has now yielded data, increased understanding, and generated ideas resulting in the new concepts described here. Early mirror research was carried out with circular axisymmetric magnets. These plasmas were MHD unstable due to the unfavorable magnetic curvature near the mid-plane. Then the minimum-B concept emerged in which the field line curvature was everywhere favorable and the plasma was situated in a MHD stable magnetic well (70% average beta in 2XII-B). The Ioffe-bar or baseball-coil became the standard for over 40 years. In the 1980's, driven by success with minimum-B stabilization and the control of ion cyclotron instabilities in PR6 and 2XII-B, mirrors were viewed as a potentially attractive concept with near-term advantages as a lower Q neutron source for applications such as a hybrid fission fuel factory or toxic waste burner. However there are down sides to the minimum-B geometry: coil construction is complex; restraining magnetic forces limit field strength and mirror ratios. Furthermore, the magnetic field lines have geodesic curvature which introduces resonant and neoclassical radial transport as observed in early tandem mirror experiments. So what now leads us to think that simple axisymmetric mirror plasmas can be stable? The Russian GDT experiment achieves on-axis 60% beta by peaking of the kinetic plasma pressure near the mirror throat (where the curvature is favorable) to counter-balance the average unfavorable mid-plane curvature. Then a modest augmentation of plasma pressure in the expander results in stability. The GDT

Mirror symmetry, mirror map and applications to complete intersection Calabi-Yau spaces

CERN Document Server

Hosono, S.; Theisen, S.; Yau, Shing-Tung

1995-01-01

We extend the discussion of mirror symmetry, Picard-Fuchs equations, instanton corrected Yukawa couplings and the topological one loop partition function to the case of complete intersections with higher dimensional moduli spaces. We will develop a new method of obtaining the instanton corrected Yukawa couplings through a study of the solutions of the Picard-Fuchs equations. This leads to closed formulas for the prepotential for the K\\"ahler moduli fields induced from the ambient space for all complete intersections in nonsingular weighted projective spaces. As examples we treat part of the moduli space of the phenomenologically interesting three generation models which are found in this class. We also apply our method to solve the simplest model in which topology change was observed and discuss examples of complete intersections in singular ambient spaces.

Multimodal Representation Contributes to the Complex Development of Science Literacy in a College Biology Class

Science.gov (United States)

Bennett, William Drew

2011-01-01

This study is an investigation into the science literacy of college genetics students who were given a modified curriculum to address specific teaching and learning problems from a previous class. This study arose out of an interest by the professor and researcher to determine how well students in the class Human Genetics in the 21st Century…

Reaching the Next Stephen Hawking: Five Ways to Help Students with Disabilities in Advanced Placement Science Classes

Science.gov (United States)

Howard, Lori A.; Potts, Elizabeth A.; Linz, Ed

2013-01-01

As the federal government encourages all students to attempt advanced math and science courses, more students with disabilities are enrolling in Advanced Placement (AP) science classes. AP science teachers can better serve these students by understanding the various types of disabilities (whether physical, learning, emotional, or behavioral),…

Ethics Is Not Rocket Science: How to Have Ethical Discussions in Your Science Class

Directory of Open Access Journals (Sweden)

Kelly C. Smith

2014-10-01

Full Text Available The Rutland Institute for Ethics at Clemson University seeks to encourage discussion on campus, in businesses, and in the community about how ethical decision-making can be the basis of both personal and professional success.  In the last 15 years, our fellows have, among other things, served as Co-PI’s on a wide range of grants, produced Responsible Conduct of Research training for science and engineering graduate students and faculty, managed the ethics curriculum at a medical school, and produced video lectures on ethical thinking for undergraduate Biology majors.  The crown jewel of our efforts to-date is our Ethics Across the Curriculum program, affectionately known as “ethics boot camp.”Each year, we bring faculty from all corners of the disciplinary spectrum together to show them how to have rich ethical discussions in their own classes with the students from their majors.  The program has been extremely successful and over the past 15 years has touched the lives of hundreds of faculty and thousands of students.  The purpose of this paper is to provide a very abbreviated version of the Rutland Ethics Across the Curriculum material to a wider audience of science educators.  It is our hope that this will motivate more faculty to introduce ethics into their classes as well as provide them the basic tools they will need to make this experience fruitful for all concerned.

Concept study of an automatic ellipsoidal mirror furnace facility, prephase A. Volume 1: Executive summary

Science.gov (United States)

Stapelmann, J.

1982-11-01

A 1500C (max) mirror for materials science experiments and for growing 40 mm crystals under microgravity in an add-on payload for a retrievable carrier is proposed. Parts of the Spacelab mirror furnaces which can be used are identified. Design solutions for modifications due to experimental requirements or to the automatic operation mode are developed. The complete new parts of the facility, such as the sample storage and exchange mechanism (SSEM) were investigated, and design solutions are presented. A design featuring two monoellipsoidal mirror furnaces with the SSEM situated in between, and no active control, is favored.

Advances in thermal control and performance of the MMT M1 mirror

Science.gov (United States)

Gibson, J. D.; Williams, G. G.; Callahan, S.; Comisso, B.; Ortiz, R.; Williams, J. T.

2010-07-01

Strategies for thermal control of the 6.5-meter diameter borosilicate honeycomb primary (M1) mirror at the MMT Observatory have included: 1) direct control of ventilation system chiller setpoints by the telescope operator, 2) semiautomated control of chiller setpoints, using a fixed offset from the ambient temperature, and 3) most recently, an automated temperature controller for conditioned air. Details of this automated controller, including the integration of multiple chillers, heat exchangers, and temperature/dew point sensors, are presented here. Constraints and sanity checks for thermal control are also discussed, including: 1) mirror and hardware safety, 2) aluminum coating preservation, and 3) optimization of M1 thermal conditions for science acquisition by minimizing both air-to-glass temperature differences, which cause mirror seeing, and internal glass temperature gradients, which cause wavefront errors. Consideration is given to special operating conditions, such as high dew and frost points. Precise temperature control of conditioned ventilation air as delivered to the M1 mirror cell is also discussed. The performance of the new automated controller is assessed and compared to previous control strategies. Finally, suggestions are made for further refinement of the M1 mirror thermal control system and related algorithms.

'It's All Done With Mirrors': V.S. Ramachandran and the Material Culture of Phantom Limb Research.

Science.gov (United States)

Guenther, Katja

2016-07-01

This article examines the material culture of neuroscientist Vilayanur S. Ramachandran's research into phantom limbs. In the 1990s Ramachandran used a 'mirror box' to 'resurrect' phantom limbs and thus to treat the pain that often accompanied them. The experimental success of his mirror therapy led Ramachandran to see mirrors as a useful model of brain function, a tendency that explains his attraction to work on 'mirror neurons'. I argue that Ramachandran's fascination with and repeated appeal to the mirror can be explained by the way it allowed him to confront a perennial problem in the mind and brain sciences, that of the relationship between a supposedly immaterial mind and a material brain. By producing what Ramachandran called a 'virtual reality', relating in varied and complex ways to the material world, the mirror reproduced a form of psycho-physical parallelism and dualistic ontology, while conforming to the materialist norms of neuroscience today.

Scientist Spotlight Homework Assignments Shift Students' Stereotypes of Scientists and Enhance Science Identity in a Diverse Introductory Science Class.

Science.gov (United States)

Schinske, Jeffrey N; Perkins, Heather; Snyder, Amanda; Wyer, Mary

2016-01-01

Research into science identity, stereotype threat, and possible selves suggests a lack of diverse representations of scientists could impede traditionally underserved students from persisting and succeeding in science. We evaluated a series of metacognitive homework assignments ("Scientist Spotlights") that featured counterstereotypical examples of scientists in an introductory biology class at a diverse community college. Scientist Spotlights additionally served as tools for content coverage, as scientists were selected to match topics covered each week. We analyzed beginning- and end-of-course essays completed by students during each of five courses with Scientist Spotlights and two courses with equivalent homework assignments that lacked connections to the stories of diverse scientists. Students completing Scientist Spotlights shifted toward counterstereotypical descriptions of scientists and conveyed an enhanced ability to personally relate to scientists following the intervention. Longitudinal data suggested these shifts were maintained 6 months after the completion of the course. Analyses further uncovered correlations between these shifts, interest in science, and course grades. As Scientist Spotlights require very little class time and complement existing curricula, they represent a promising tool for enhancing science identity, shifting stereotypes, and connecting content to issues of equity and diversity in a broad range of STEM classrooms. © 2016 J. N. Schinske et al. CBE—Life Sciences Education © 2016 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

The Colorado Learning Attitudes about Science Survey (CLASS) for Use in Biology

Science.gov (United States)

Semsar, Katharine; Knight, Jennifer K.; Birol, Gülnur; Smith, Michelle K.

2011-01-01

This paper describes a newly adapted instrument for measuring novice-to-expert-like perceptions about biology: the Colorado Learning Attitudes about Science Survey for Biology (CLASS-Bio). Consisting of 31 Likert-scale statements, CLASS-Bio probes a range of perceptions that vary between experts and novices, including enjoyment of the discipline, propensity to make connections to the real world, recognition of conceptual connections underlying knowledge, and problem-solving strategies. CLASS-Bio has been tested for response validity with both undergraduate students and experts (biology PhDs), allowing student responses to be directly compared with a consensus expert response. Use of CLASS-Bio to date suggests that introductory biology courses have the same challenges as introductory physics and chemistry courses: namely, students shift toward more novice-like perceptions following instruction. However, students in upper-division biology courses do not show the same novice-like shifts. CLASS-Bio can also be paired with other assessments to: 1) examine how student perceptions impact learning and conceptual understanding of biology, and 2) assess and evaluate how pedagogical techniques help students develop both expertise in problem solving and an expert-like appreciation of the nature of biology. PMID:21885823

The Colorado Learning Attitudes about Science Survey (CLASS) for use in Biology.

Science.gov (United States)

Semsar, Katharine; Knight, Jennifer K; Birol, Gülnur; Smith, Michelle K

2011-01-01

This paper describes a newly adapted instrument for measuring novice-to-expert-like perceptions about biology: the Colorado Learning Attitudes about Science Survey for Biology (CLASS-Bio). Consisting of 31 Likert-scale statements, CLASS-Bio probes a range of perceptions that vary between experts and novices, including enjoyment of the discipline, propensity to make connections to the real world, recognition of conceptual connections underlying knowledge, and problem-solving strategies. CLASS-Bio has been tested for response validity with both undergraduate students and experts (biology PhDs), allowing student responses to be directly compared with a consensus expert response. Use of CLASS-Bio to date suggests that introductory biology courses have the same challenges as introductory physics and chemistry courses: namely, students shift toward more novice-like perceptions following instruction. However, students in upper-division biology courses do not show the same novice-like shifts. CLASS-Bio can also be paired with other assessments to: 1) examine how student perceptions impact learning and conceptual understanding of biology, and 2) assess and evaluate how pedagogical techniques help students develop both expertise in problem solving and an expert-like appreciation of the nature of biology.

Clinical characteristics of mirror syndrome: a comparison of 10 cases of mirror syndrome with non-mirror syndrome fetal hydrops cases.

Science.gov (United States)

Hirata, Go; Aoki, Shigeru; Sakamaki, Kentaro; Takahashi, Tsuneo; Hirahara, Fumiki; Ishikawa, Hiroshi

2016-01-01

To investigate clinical features of mirror syndrome. We retrospectively reviewed 71 cases of fetal hydrops with or without mirror syndrome, and compared with respect to maternal age, the body mass index, the primipara rate, the gestational age at delivery, the timing of fetal hydrops onset, the severity of fetal edema, placental swelling, the laboratory data and the fetal mortality. The data are expressed as the medians. Mirror syndrome developed in 29% (10/35) of the cases with fetal hydrops. In mirror group, the onset time of fetal hydrops was significantly earlier (29 weeks versus 31 weeks, p = 0.011), and the severity of fetal hydrops (fetal edema/biparietal diameter) was significantly higher than non-mirror group (0.23 versus 0.16, p < 0.001). There was significantly higher serum human chorionic gonadotropin (hCG) (453,000 IU/L versus 80,000 IU/L, p < 0.001) and lower hemoglobin (8.9 g/dL versus 10.1 g/dL, p =0.002), hypoalbuminemia (2.3 mg/dL versus 2.7 mg/dL, p = 0.007), hyperuricemia (6.4 mg/dL versus 5.0 mg/dL, p = 0.043) in mirror group. Mirror syndrome is occurred frequently in early and severe fetal hydrops and cause hemodilution and elevation of serum hCG.

Small mirror fusion reactors

International Nuclear Information System (INIS)

Carlson, G.A.; Schultz, K.R.; Smith, A.C. Jr.

1978-01-01

Basic requirements for the pilot plants are that they produce a net product and that they have a potential for commercial upgrade. We have investigated a small standard mirror fusion-fission hybrid, a two-component tandem mirror hybrid, and two versions of a field-reversed mirror fusion reactor--one a steady state, single cell reactor with a neutral beam-sustained plasma, the other a moving ring field-reversed mirror where the plasma passes through a reaction chamber with no energy addition

A transcranial magnetic stimulation study of the effect of visual orientation on the putative human mirror neuron system

OpenAIRE

Burgess, Jed D.; Arnold, Sara L.; Fitzgibbon, Bernadette M.; Fitzgerald, Paul B.; Enticott, Peter G.

2013-01-01

Mirror neurons are a class of motor neuron that are active during both the performance and observation of behavior, and have been implicated in interpersonal understanding There is evidence to suggest that the mirror response is modulated by the perspective from which an action is presented (e.g., egocentric or allocentric). Most human research, however, has only examined this when presenting intransitive actions. Twenty-three healthy adult participants completed a transcranial magnetic stimu...

Bronze rainbow hologram mirrors

Science.gov (United States)

Dawson, P.

2006-02-01

This project draws on holographic embossing techniques, ancient artistic conventions of bronze mirror design and modelling and casting processes to accomplish portraiture of reflection. Laser scanning, 3D computer graphics and holographic imaging are employed to enable a permanent 3D static holographic image to appear integrated with the real-time moving reflection of a viewer's face in a polished bronze disc. The disc and the figure which holds it (caryatid) are cast in bronze from a lost wax model, a technique which has been used for millennia to make personal mirrors. The Caryatid form of bronze mirror which went through many permutations in ancient Egyptian, Greece and Rome shows a plethora of expressive figure poses ranging from sleek nudes to highly embellished multifigure arrangements. The prototype of this series was made for Australian choreographer Graeme Murphy, Artistic Director of the Sydney Dance Company. Each subsequent mirror will be unique in figure and holographic imagery as arranged between artist and subject. Conceptually this project references both the modern experience of viewing mirrors retrieved from ancient tombs, which due to deterioration of the surface no longer reflect, and the functioning of Chinese Magic mirrors, which have the ability to project a predetermined image. Inspired by the metaphorical potential of these mirrors, which do not reflect the immediate reality of the viewer, this bronze hologram mirror series enables each viewer to reflect upon himself or herself observing simultaneously the holographic image and their own partially obliterated reflection.

The importance of teacher interpersonal behaviour for student attitudes in Brunei primary science classes

NARCIS (Netherlands)

Brok, den P.J.; Fisher, D.; Scott, R.

2005-01-01

This study investigated relationships between students' perceptions of their teachers' interpersonal behaviour and their subject-related attitude in primary science classes in Brunei. Teacher-student interpersonal behaviour was mapped with the Questionnaire on Teacher Interaction (QTI) and reported

Mirror Fusion Test Facility: an intermediate device to a mirror fusion reactor

International Nuclear Information System (INIS)

Karpenko, V.N.

1983-01-01

The Mirror Fusion Test Facility (MFTF-B) now under construction at Lawrence Livermore National Laboratory represents more than an order-of-magnitude step from earlier magnetic-mirror experiments toward a future mirror fusion reactor. In fact, when the device begins operating in 1986, the Lawson criteria of ntau = 10 14 cm -3 .s will almost be achieved for D-T equivalent operation, thus signifying scientific breakeven. Major steps have been taken to develop MFTF-B technologies for tandem mirrors. Steady-state, high-field, superconducting magnets at reactor-revelant scales are used in the machine. The 30-s beam pulses, ECRH, and ICRH will also introduce steady-state technologies in those systems

Mirror plasma apparatus

International Nuclear Information System (INIS)

Moir, R.W.

1981-01-01

A mirror plasma apparatus which utilizes shielding by arc discharge to form a blanket plasma and lithium walls to reduce neutron damage to the wall of the apparatus. An embodiment involves a rotating liquid lithium blanket for a tandem mirror plasma apparatus wherein the first wall of the central mirror cell is made of liquid lithium which is spun with angular velocity great enough to keep the liquid lithium against the first material wall, a blanket plasma preventing the lithium vapor from contaminating the plasma

Geometry of mirror manifolds

International Nuclear Information System (INIS)

Aspinwall, P.S.; Luetken, C.A.

1991-01-01

We analyze the mirror manifold hypothesis in one and three dimensions using the simplest available representations of the N = 2 superconformal algebra. The symmetries of these tensor models can be divided out to give an explicit representation of the mirror, and we give a simple group theoretical algorithm for determining which symmetries should be used. We show that the mirror of a superconformal field theory does not always have a geometrical interpretation, but when it does, deformations of complex structure of one manifold are reflected in deformations of the Kaehler form of the mirror manifold, and we show how the large radius limit of a manifold corresponds to a large complex structure limit in the mirror manifold. The mirror of the Tian-Yau three generation model is constructed both as a conformal field theory and as an algebraic variety with Euler number six. The Hodge numbers of this manifolds are fixed, but the intersection numbes are highly ambiguous, presumably reflected a rich structure of multicritical points in the moduli space of the field theory. (orig.)

Mirror, Mirror by the Stairs: The Impact of Mirror Exposure on Stair versus Elevator Use in College Students.

Science.gov (United States)

Hodgin, Katie L; Graham, Dan J

2016-01-01

Previous research has indicated that self-awareness-inducing mirrors can successfully incite behaviors that align with one's personal values, such as helping others. Other research has found a large discrepancy between the high percentage of young adults who report valuing the healthfulness of physical activity (PA) and the low percentage who actually meet PA participation standards. However, few studies have examined how mirror exposure and both perceived and actual body size influence highly valued PA participation among college students. The present study assessed stair versus elevator use on a western college campus and hypothesized that mirror exposure would increase the more personally healthy transportation method of stair use. In accordance with previous research, it was also hypothesized that males and those with a lower body mass index (BMI) would be more likely to take the stairs, and that body size distorting mirrors would impact the stair-elevator decision. One hundred sixty-seven students (51% male) enrolled in an introductory psychology course were recruited to take a survey about their "transportation choices" at an indoor campus parking garage. Participants were individually exposed to either no mirror, a standard full-length mirror, or a full-length mirror manipulated to make the reflected body size appear either slightly thinner or slightly wider than normal before being asked to go to the fourth floor of the garage for a survey. Participants' choice of floor-climbing method (stairs or elevator) was recorded, and they were administered an Internet-based survey assessing demographic information, BMI, self-awareness, perceived body size, and other variables likely to be associated with stair use. Results from logistic regression analyses revealed that participants who were not exposed to a mirror [odds ratios (OR) = 0.37, 95% CI: 0.14-0.96], males (OR = 0.33, 95% CI: 0.13-0.85), those with lower BMI (OR = 0.84, 95% CI: 0.71-0.99), those

Mirror, Mirror by the Stairs: The Impact of Mirror Exposure on Stair versus Elevator Use in College Students

Directory of Open Access Journals (Sweden)

Katie L Hodgin

2016-04-01

Full Text Available AbstractPrevious research has indicated that self-awareness-inducing mirrors can successfully incite behaviors that align with one’s personal values, such as helping others. Other research has found a large discrepancy between the high percentage of young adults who report valuing the healthfulness of physical activity (PA and the low percentage who actually meet PA participation standards. Few studies, however, have examined how mirror exposure and both perceived and actual body size influence highly-valued PA participation among college students. The present study assessed stair versus elevator use on a western college campus and hypothesized that mirror exposure would increase the more personally-healthy transportation method of stair use. In accordance with previous research, it was also hypothesized that males and those with a lower body mass index (BMI would be more likely to take the stairs, and that body-size distorting mirrors would impact the stair-elevator decision. One hundred and sixty-seven students (51% male enrolled in an introductory psychology course were recruited to take a survey about their transportation choices at an indoor campus parking garage. Participants were individually exposed to either no mirror, a standard full-length mirror, or a full-length mirror manipulated to make the reflected body size appear either slightly thinner or slightly wider than normal before being asked to go to the fourth floor of the garage for a survey. Participants’ choice of floor climbing method (stairs or elevator was recorded and they were administered an internet-based survey assessing demographic information, BMI, self-awareness, perceived body size, and other variables likely to be associated with stair use. Results from logistic regression analyses revealed that participants who were not exposed to a mirror (OR = 0.37, 95% CI: 0.14 – 0.96, males (OR = 0.33, 95% CI: 0.13 – 0.85, those with lower BMI (OR = 0.84, 95% CI: 0.71 �

Gasdynamic Mirror Fusion Propulsion Experiment

Science.gov (United States)

Emrich, Bill; Rodgers, Stephen L. (Technical Monitor)

2000-01-01

A gasdynamic mirror (GDM) fusion propulsion experiment is currently being constructed at the NASA Marshall Space Flight Center (MSFC) to test the feasibility of this particular type of fusion device. Because of the open magnetic field line configuration of mirror fusion devices, they are particularly well suited for propulsion system applications since they allow for the easy ejection of thrust producing plasma. Currently, the MSFC GDM is constructed in three segments. The vacuum chamber mirror segment, the plasma injector mirror segment, and the main plasma chamber segment. Enough magnets are currently available to construct up to three main plasma chamber segments. The mirror segments are also segmented such that they can be expanded to accommodate new end plugging strategies with out requiring the disassembly of the entire mirror segment. The plasma for the experiment is generated in a microwave cavity located between the main magnets and the mirror magnets. Ion heating is accomplished through ambipolar diffusion. The objective of the experiment is to investigate the stability characteristics of the gasdynamic mirror and to map a region of parameter space within which the plasma can be confined in a stable steady state configuration. The mirror ratio, plasma density, and plasma "b" will be varied over a range of values and measurements subsequently taken to determine the degree of plasma stability.

A transcranial magnetic stimulation study of the effect of visual orientation on the putative human mirror neuron system

Science.gov (United States)

Burgess, Jed D.; Arnold, Sara L.; Fitzgibbon, Bernadette M.; Fitzgerald, Paul B.; Enticott, Peter G.

2013-01-01

Mirror neurons are a class of motor neuron that are active during both the performance and observation of behavior, and have been implicated in interpersonal understanding. There is evidence to suggest that the mirror response is modulated by the perspective from which an action is presented (e.g., egocentric or allocentric). Most human research, however, has only examined this when presenting intransitive actions. Twenty-three healthy adult participants completed a transcranial magnetic stimulation experiment that assessed corticospinal excitability whilst viewing transitive hand gestures from both egocentric (i.e., self) and allocentric (i.e., other) viewpoints. Although action observation was associated with increases in corticospinal excitability (reflecting putative human mirror neuron activity), there was no effect of visual perspective. These findings are discussed in the context of contemporary theories of mirror neuron ontogeny, including models concerning associative learning and evolutionary adaptation. PMID:24137125

A transcranial magnetic stimulation study of the effect of visual orientation on the putative human mirror neuron system.

Science.gov (United States)

Burgess, Jed D; Arnold, Sara L; Fitzgibbon, Bernadette M; Fitzgerald, Paul B; Enticott, Peter G

2013-01-01

Mirror neurons are a class of motor neuron that are active during both the performance and observation of behavior, and have been implicated in interpersonal understanding. There is evidence to suggest that the mirror response is modulated by the perspective from which an action is presented (e.g., egocentric or allocentric). Most human research, however, has only examined this when presenting intransitive actions. Twenty-three healthy adult participants completed a transcranial magnetic stimulation experiment that assessed corticospinal excitability whilst viewing transitive hand gestures from both egocentric (i.e., self) and allocentric (i.e., other) viewpoints. Although action observation was associated with increases in corticospinal excitability (reflecting putative human mirror neuron activity), there was no effect of visual perspective. These findings are discussed in the context of contemporary theories of mirror neuron ontogeny, including models concerning associative learning and evolutionary adaptation.

Review of mirror fusion reactor designs

International Nuclear Information System (INIS)

Bender, D.J.

1977-01-01

Three magnetic confinement concepts, based on the mirror principle, are described. These mirror concepts are summarized as follows: (1) fusion-fission hybrid reactor, (2) tandem mirror reactor, and (3) reversed field mirror reactor

The obsidian mirror The obsidian mirror

Directory of Open Access Journals (Sweden)

Maria do Socorro Reis Amorin

2008-04-01

Full Text Available The author James Norman is an American who has always lived in Mexico during the summer. He seems to love Mexican - Indian traditions and he is well acquainted with the pre-historic culture as it is shown in his book: "The Obsidian Mirror". "The Obsidian Mirror" is a mysterious story about an archeologist: Quigley that lives in a small village in Mexico-San Marcos. He is searching for antiques that belong to some tribes of pre-historic Indians in order to find out their mysteries. Quigley becomes so engaged in his work that his mind has reached a stage that is impossible to separate between Quigley the archeologist, and Quigley as an ancient Indian. The culture, the myth, the sensation of Omen - characteristics of the Indians are within himself. As a result, Quigley acts sometimes as a real Indian. The author James Norman is an American who has always lived in Mexico during the summer. He seems to love Mexican - Indian traditions and he is well acquainted with the pre-historic culture as it is shown in his book: "The Obsidian Mirror". "The Obsidian Mirror" is a mysterious story about an archeologist: Quigley that lives in a small village in Mexico-San Marcos. He is searching for antiques that belong to some tribes of pre-historic Indians in order to find out their mysteries. Quigley becomes so engaged in his work that his mind has reached a stage that is impossible to separate between Quigley the archeologist, and Quigley as an ancient Indian. The culture, the myth, the sensation of Omen - characteristics of the Indians are within himself. As a result, Quigley acts sometimes as a real Indian.

A human mirror neuron system for language: Perspectives from signed languages of the deaf.

Science.gov (United States)

Knapp, Heather Patterson; Corina, David P

2010-01-01

Language is proposed to have developed atop the human analog of the macaque mirror neuron system for action perception and production [Arbib M.A. 2005. From monkey-like action recognition to human language: An evolutionary framework for neurolinguistics (with commentaries and author's response). Behavioral and Brain Sciences, 28, 105-167; Arbib M.A. (2008). From grasp to language: Embodied concepts and the challenge of abstraction. Journal de Physiologie Paris 102, 4-20]. Signed languages of the deaf are fully-expressive, natural human languages that are perceived visually and produced manually. We suggest that if a unitary mirror neuron system mediates the observation and production of both language and non-linguistic action, three prediction can be made: (1) damage to the human mirror neuron system should non-selectively disrupt both sign language and non-linguistic action processing; (2) within the domain of sign language, a given mirror neuron locus should mediate both perception and production; and (3) the action-based tuning curves of individual mirror neurons should support the highly circumscribed set of motions that form the "vocabulary of action" for signed languages. In this review we evaluate data from the sign language and mirror neuron literatures and find that these predictions are only partially upheld. 2009 Elsevier Inc. All rights reserved.

From Peripheral to Central, the Story of Melanie's Metamorphosis in an Urban Middle School Science Class

Science.gov (United States)

Tan, Edna; Barton, Angela Calabrese

2008-01-01

Identity formation is a critical dimension of how and why students engage in science to varying degrees. In this paper, we use the lens of identity formation, and in particular identities in practice, to make sense of how and why Melanie, over the course of sixth grade, transformed from a marginalized member of the science class with a failing…

Reading and Note Taking in Monological and Dialogical Classes in the Social Sciences

Science.gov (United States)

Cartolari, Manuela; Carlino, Paula; Colombo, Laura M.

2013-01-01

This qualitative study explores the uses of reading and note-taking in two pre-service teacher training Social Sciences courses. Data analysis of in-depth interviews with professors and students, class observations and course materials suggested two polar teaching styles according to how bibliography was included in the course and the presence or…

Tandem mirror plasma confinement apparatus

Science.gov (United States)

Fowler, T. Kenneth

1978-11-14

Apparatus and method for confining a plasma in a center mirror cell by use of two end mirror cells as positively charged end stoppers to minimize leakage of positive particles from the ends of the center mirror cell.

Magneto-hydrodynamically stable axisymmetric mirrors

Energy Technology Data Exchange (ETDEWEB)

Ryutov, D. D.; Cohen, B. I.; Molvik, A. W. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Berk, H. L. [University of Texas, Austin, Texas 78712 (United States); Simonen, T. C. [University of California, Berkeley, California 94720 (United States)

2011-09-15

Making axisymmetric mirrors magnetohydrodynamically (MHD) stable opens up exciting opportunities for using mirror devices as neutron sources, fusion-fission hybrids, and pure-fusion reactors. This is also of interest from a general physics standpoint (as it seemingly contradicts well-established criteria of curvature-driven instabilities). The axial symmetry allows for much simpler and more reliable designs of mirror-based fusion facilities than the well-known quadrupole mirror configurations. In this tutorial, after a summary of classical results, several techniques for achieving MHD stabilization of the axisymmetric mirrors are considered, in particular: (1) employing the favorable field-line curvature in the end tanks; (2) using the line-tying effect; (3) controlling the radial potential distribution; (4) imposing a divertor configuration on the solenoidal magnetic field; and (5) affecting the plasma dynamics by the ponderomotive force. Some illuminative theoretical approaches for understanding axisymmetric mirror stability are described. The applicability of the various stabilization techniques to axisymmetric mirrors as neutron sources, hybrids, and pure-fusion reactors are discussed; and the constraints on the plasma parameters are formulated.

Survey of mirror machine reactors

International Nuclear Information System (INIS)

Condit, W.C.

1978-01-01

The Magnetic Mirror Fusion Program is one of the two main-line fusion efforts in the United States. Starting from the simple axisymmetric mirror concept in the 1950's, the program has successfully overcome gross flute-type instabilities (using minimum-B magnetic fields), and the most serious of the micro-instabilities which plagued it (the drift-cyclotron loss-cone mode). Dense plasmas approaching the temperature range of interest for fusion have been created (n/sub p/ = 10 14 /cc at 10 to 12 keV). At the same time, rather extensive conceptual design studies of possible mirror configurations have led to three principle designs of interest: the standard mirror fission-fusion hybrid, tandem mirror, and the field-reversed mirror. The lectures will discuss these three concepts in turn. There will be no discussion of diagnostics for the mirror machine in these lectures, but typical plasma parameters will be given for each type of machine, and the diagnostic requirements will be apparent. In a working fusion reactor, diagnostics will be required for operational control, and remarks will be made on this subject

Tandem mirror plasma confinement apparatus

International Nuclear Information System (INIS)

Fowler, T.K.

1978-01-01

Apparatus and method are described for confining a plasma in a center mirror cell by use of two end mirror cells as positively charged end stoppers to minimize leakage of positive particles from the ends of the center mirror cell

The mirror-neuron system.

Science.gov (United States)

Rizzolatti, Giacomo; Craighero, Laila

2004-01-01

A category of stimuli of great importance for primates, humans in particular, is that formed by actions done by other individuals. If we want to survive, we must understand the actions of others. Furthermore, without action understanding, social organization is impossible. In the case of humans, there is another faculty that depends on the observation of others' actions: imitation learning. Unlike most species, we are able to learn by imitation, and this faculty is at the basis of human culture. In this review we present data on a neurophysiological mechanism--the mirror-neuron mechanism--that appears to play a fundamental role in both action understanding and imitation. We describe first the functional properties of mirror neurons in monkeys. We review next the characteristics of the mirror-neuron system in humans. We stress, in particular, those properties specific to the human mirror-neuron system that might explain the human capacity to learn by imitation. We conclude by discussing the relationship between the mirror-neuron system and language.

Physics of mirror systems

International Nuclear Information System (INIS)

Post, R.F.

1982-05-01

In recent years the emphasis in research on the magnetic mirror approach to fusion has been shifted to address what are essentially economically-motivated issues. The introduction of the Tandem Mirror idea solved in principal the problem of low Q (low fusion power gain) of mirror-based fusion systems. In order to optimize the tandem mirror idea from an economic standpoint, some important improvements have been suggested. These improvements include the thermal barrier idea of Baldwin and Logan and the axicell concept of Kesner. These new modifications introduce some special physics considerations. Among these are (1) The MHD stability properties of high energy electron components in the end cells; (2) The optimization of end-cell magnetic field configurations with the objective of minimizing equilibrium parallel currents; (3) The suppression of microstabilities by use of sloshing ion distributions. Following a brief outline of tandem mirror concepts, the above three topics are discussed, with illustrative examples taken from earlier work or from recent design studies

Physics of mirror fusion systems

International Nuclear Information System (INIS)

Post, R.F.

1976-01-01

Recent experimental results with the 2XIIB mirror machine at Lawrence Livermore Laboratory have demonstrated the stable confinement of plasmas at fusion temperatures and with energy densities equaling or exceeding that of the confining fields. The physics of mirror confinement is discussed in the context of these new results. Some possible approaches to further improving the confinement properties of mirror systems and the impact of these new approaches on the prospects for mirror fusion reactors are discussed

Thermal effects on beryllium mirrors

International Nuclear Information System (INIS)

Weinswig, S.

1989-01-01

Beryllium is probably the most frequently used material for spaceborne system scan mirrors. Beryllium's properties include lightweightedness, high Young's modulus, high stiffness value, high resonance value. As an optical surface, beryllium is usually nickel plated in order to produce a higher quality surface. This process leads to the beryllium mirror acting like a bimetallic device. The mirror's deformation due to the bimetallic property can possibly degrade the performance of the associated optical system. As large space borne systems are designed and as temperature considerations become more crucial in the instruments, the concern about temporal deformation of the scan mirrors becomes a prime consideration. Therefore, two sets of tests have been conducted in order to ascertain the thermal effects on nickel plated beryllium mirrors. These tests are categorized. The purpose of this paper is to present the values of the bimetallic effect on typical nickel plated beryllium mirrors

A transcranial magnetic stimulation study of the effect of visual orientation on the putative human mirror neuron system

Directory of Open Access Journals (Sweden)

Jed Donald Burgess

2013-10-01

Full Text Available Mirror neurons are a class of motor neuron that are active during both the performance and observation of behavior, and have been implicated in interpersonal understanding There is evidence to suggest that the mirror response is modulated by the perspective from which an action is presented (e.g., egocentric or allocentric. Most human research, however, has only examined this when presenting intransitive actions. Twenty-three healthy adult participants completed a transcranial magnetic stimulation (TMS experiment that assessed corticospinal excitability whilst viewing transitive hand gestures from both egocentric (i.e., self and allocentric (i.e., other viewpoints. Although action observation was associated with increases in corticospinal excitability (reflecting putative human mirror neuron activity, there was no effect of visual perspective. These findings are discussed in the context of contemporary theories of mirror neuron ontogeny, including models concerning associative learning and evolutionary adaptation.

Near-field flat focusing mirrors

Science.gov (United States)

Cheng, Yu-Chieh; Staliunas, Kestutis

2018-03-01

This article reviews recent progress towards the design of near-field flat focusing mirrors, focusing/imaging light patterns in reflection. An important feature of such flat focusing mirrors is their transverse invariance, as they do not possess any optical axis. We start with a review of the physical background to the different focusing mechanisms of near- and far-field focusing. These near-field focusing devices like flat lenses and the reviewed near-field focusing mirrors can implement planar focusing devices without any optical axis. In contrast, various types of far-field planar focusing devices, such as high-contrast gratings and metasurfaces, unavoidably break the transverse invariance due to their radially symmetrical structures. The particular realizations of near-field flat focusing mirrors including Bragg-like dielectric mirrors and dielectric subwavelength gratings are the main subjects of the review. The first flat focusing mirror was demonstrated with a chirped mirror and was shown to manage an angular dispersion for beam focusing, similar to the management of chromatic dispersion for pulse compression. Furthermore, the reviewed optimized chirped mirror demonstrated a long near-field focal length, hardly achieved by a flat lens or a planar hyperlens. Two more different configurations of dielectric subwavelength gratings that focus a light beam at normal or oblique incidence are also reviewed. We also summarize and compare focusing performance, limitations, and future perspectives between the reviewed flat focusing mirrors and other planar focusing devices including a flat lens with a negative-index material, a planar hyperlens, a high-contrast grating, and a metasurface.

Potential measurements in tandem mirrors

International Nuclear Information System (INIS)

Glowienka, J.C.

1985-11-01

The US mirror program has begun conducting experiments with a thermal barrier tandem mirror configuration. This configuration requires a specific axial potential profile and implies measurements of potential for documentation and optimization of the configuration. This report briefly outlines the motivation for the thermal barrier tandem mirror and then outlines the techniques used to document the potential profile in conventional and thermal barrier tandem mirrors. Examples of typical data sets from the world's major tandem mirror experiments, TMX and TMX-U at Lawrence Livermore National Laboratory (LLNL) and Gamma 10 at Tsukuba University in Japan, and the current interpretation of the data are discussed together with plans for the future improvement of measurements of plasma potential

TCV mirrors cleaned by plasma

Directory of Open Access Journals (Sweden)

L. Marot

2017-08-01

Full Text Available Metallic mirrors exposed in TCV tokamak were cleaned by plasma in laboratory. A gold (Au mirror was deposited with 185–285nm of amorphous carbon (aC:D film coming from the carbon tiles of TCV. Another molybdenum (Mo mirror had a thicker deposit due to a different location within the tokamak. The thickness measurements were carried out using ellipsometry and the reflectivity measurements performed by spectrophotometry revealed a decrease of the specular reflectivity in the entire range (250–2500nm for the Mo mirror and specifically in the visible spectrum for the Au. Comparison of the simulated reflectivity using a refractive index of 1.5 and a Cauchy model for the aC:D gives good confidence on the estimated film thickness. Plasma cleaning using radio frequency directly applied to a metallic plate where the mirrors were fixed demonstrated the ability to remove the carbon deposits. A mixture of 50% hydrogen and 50% helium was used with a −200V self-bias. Due to the low sputtering yield of He and the low chemical erosion of hydrogen leading to volatile molecules, 20h of cleaning were needed for Au mirror and more than 60h for Mo mirror. Recovery of the reflectivity was not complete for the Au mirror most likely due to damage of the surface during tokamak exposure (breakdown phenomena.

A multilevel analysis of teacher interpersonal behaviour and student attitudes in Brunei primary science classes

NARCIS (Netherlands)

Scott, R.; Brok, den P.J.; Fisher, D.; Putnam, R.; Borko, H.

2004-01-01

This study investigated relationships between students’ perceptions of their teachers’ interpersonal behaviour and their subject-related attitude in primary science classes in Brunei. Teacher-student interpersonal behaviour was mapped with the Questionnaire on Teacher Interaction (QTI) and reported

Overview and Recent Accomplishments of the Advanced Mirror Technology Development (AMTD) for Large Aperture UVOIR Space Telescopes Project

Science.gov (United States)

Stahl, H. Philip

2013-01-01

Per Astro2010, a new, larger UVO telescope is needed to answer fundamental scientific questions, such as: is there life on Earth-like exoplanets; how galaxies assemble stellar populations; how baryonic matter interacts with intergalactic medium; and how solar systems form and evolve. And, present technology is not mature enough to affordably build and launch any potential UVO concept. Advanced Mirror Technology Development (AMTD) is a funded SAT project. Our objective is to mature to TRL-6 the critical technologies needed to produce 4-m or larger flight-qualified UVOIR mirrors by 2018 so that a viable mission can be considered by the 2020 Decadal Review. AMTD uses a science-driven systems engineering approach. We mature technologies required to enable the highest priority science AND result in a high-performance low-cost low-risk system. To provide the science community with options, we are pursuing multiple technology paths. We have assembled an outstanding team from academia, industry, and government with extensive expertise in astrophysics and exoplanet characterization, and in the design/manufacture of monolithic and segmented space telescopes. One of our key accomplishments is that we have derived engineering specifications for advanced normal-incidence monolithic and segmented mirror systems needed to enable both general astrophysics and ultra-high contrast observations of exoplanets missions as a function of potential launch vehicle and its inherent mass and volume constraints. We defined and initiated a program to mature 6 key technologies required to fabricate monolithic and segmented space mirrors.

Fokker-Planck equation in mirror research

International Nuclear Information System (INIS)

Post, R.F.

1983-01-01

Open confinement systems based on the magnetic mirror principle depend on the maintenance of particle distributions that may deviate substantially from Maxwellian distributions. Mirror research has therefore from the beginning relied on theoretical predictions of non-equilibrium rate processes obtained from solutions to the Fokker-Planck equation. The F-P equation plays three roles: Design of experiments, creation of classical standards against which to compare experiment, and predictions concerning mirror based fusion power systems. Analytical and computational approaches to solving the F-P equation for mirror systems will be reviewed, together with results and examples that apply to specific mirror systems, such as the tandem mirror

Mirroring patients – or not

DEFF Research Database (Denmark)

Davidsen, Annette Sofie; Fosgerau, Christina Fogtmann

2015-01-01

on studies of imitative behaviour within linguistics and psychology, we argue that interactional mirroring is an important aspect of displaying implicit mentalization. We aimed to explore if, and in that case how, mirroring is displayed by general practitioners (GPs) and psychiatrists in consultations...... with patients with depression. We wanted to see how implicit mentalizing unfolds in physician–patient interactions. Consultations were videorecorded and analysed within the framework of conversation analysis. GPs and psychiatrists differed substantially in their propensity to mirror body movements and verbal...... and acoustic features of speech. GPs mirrored their patients more than psychiatrists in all modalities and were more flexible in their interactional behaviour. Psychiatrists seemed more static, regardless of the emotionality displayed by patients. Implicitly mirroring and attuning to patients could signify...

Mirror and grating surface figure requirements for grazing incidence synchrotron radiation beamlines: Power loading effects

Energy Technology Data Exchange (ETDEWEB)

Hulbert, S.L.; Sharma, S.

1987-01-01

At present, grazing incidence mirrors are used almost exclusively as the first optical element in VUV and soft x-ray synchrotron radiation beamlines. The performance of these mirrors is determined by thermal and mechanical stress-induced figure errors as well as by figure errors remaining from the grinding and polishing process. With the advent of VUV and soft x-ray undulators and wigglers has come a new set of thermal stress problems related to both the magnitude and the spatial distribution of power from these devices. In many cases the power load on the entrance slits and gratings in these beamlines is no longer negligible. The dependence of thermally-induced front-end mirror figure errors on various storage ring and insertion device parameters (especially those at the National Synchrotron Light Source) and the effects of these figure errors on two classes of soft x-ray beamlines are presented.

Mirror symmetry for G{sub 2}-manifolds: twisted connected sums and dual tops

Energy Technology Data Exchange (ETDEWEB)

Braun, Andreas P. [Rudolf Peierls Centre for Theoretical Physics, University of Oxford,1 Keble Road, Oxford OX1 3NP (United Kingdom); Zotto, Michele Del [Simons Center for Geometry and Physics, State University of New York at Stony Brook,Stony Brook, NY, 11794-3636 (United States)

2017-05-15

Recently, at least 50 million of novel examples of compact G{sub 2} holonomy manifolds have been constructed as twisted connected sums of asymptotically cylindrical Calabi-Yau threefolds. The purpose of this paper is to study mirror symmetry for compactifications of Type II superstrings in this context. We focus on G{sub 2} manifolds obtained from building blocks constructed from dual pairs of tops, which are the closest to toric CY hypersurfaces, and formulate the analogue of the Batyrev mirror map for this class of G{sub 2} holonomy manifolds, thus obtaining several millions of novel dual superstring backgrounds. In particular, this leads us to conjecture a plethora of novel exact dualities among the corresponding 2d N=1 sigma models.

What do mirror neurons mirror?

NARCIS (Netherlands)

Uithol, S.; Rooij, I.J.E.I. van; Bekkering, H.; Haselager, W.F.G.

2011-01-01

Single cell recordings in monkeys provide strong evidence for an important role of the motor system in action understanding. This evidence is backed up by data from studies of the (human) mirror neuron system using neuroimaging or TMS techniques, and behavioral experiments. Although the data

Journal of Earth System Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Earth System Science; Volume 124; Issue 7 ... mining; sediment dynamic; suspended sediment; watershed management. ... from a hillslope or channel, mirrors the watershed health, which needs to be quantified.

Earth and Space Science Ph.D. Class of 2003 Report released

Science.gov (United States)

Keelor, Brad

AGU and the American Geological Institute (AGI) released on 26 July an employment study of 180 Earth and space science Ph.D. recipients who received degrees from U.S. universities in 2003. The AGU/AGI survey asked graduates about their education and employment, efforts to find their first job after graduation, and experiences in graduate school. Key results from the study include: The vast majority (87%) of 2003 graduates found work in the Earth and space sciences, earning salaries commensurate with or slightly higher than 2001 and 2002 salary averages. Most (64%) graduates were employed within academia (including postdoctoral appointments), with the remainder in government (19%), industry (10%), and other (7%) sectors. Most graduates were positive about their employment situation and found that their work was challenging, relevant, and appropriate for someone with a Ph.D. The percentage of Ph.D. recipients accepting postdoctoral positions (58%) increased slightly from 2002. In contrast, the fields of physics and chemistry showed significant increases in postdoctoral appointments for Ph.D.s during the same time period. As in previous years, recipients of Ph.D.s in the Earth, atmospheric, and ocean sciences (median age of 32.7 years) are slightly older than Ph.D. recipients in most other natural sciences (except computer sciences), which is attributed to time taken off between undergraduate and graduate studies. Women in the Earth, atmospheric,and ocean sciences earned 33% of Ph.D.s in the class of 2003, surpassing the percentage of Ph.D.s earned by women in chemistry (32%) and well ahead of the percentage in computer sciences (20%), physics (19%), and engineering (17%). Participation of other underrepresented groups in the Earth, atmospheric, and ocean sciences remained extremely low.

Technological and Traditional Drawing Approaches Encourage Active Engagement in Histology Classes for Science Undergraduates

Science.gov (United States)

Cogdell, Barbara; Torsney, Ben; Stewart, Katherine; Smith, Robert A.

2012-01-01

In order to promote more active engagement of science undergraduates in histology practical classes some technology-based innovations were introduced. First, an interactive pre-lab tutorial was set up using an electronic handset voting system, where guidance on tissue analysis was given. Second, a web-based resource where students could access…

Issues facing the U. S. mirror program

Energy Technology Data Exchange (ETDEWEB)

George, T.V.

1978-07-01

Some of the current issues associated with the U.S. Magnetic Mirror Program are analyzed. They are presented as five separate papers entitled: (1) Relevant Issues Broughtup by the Mirror Reactor Design Studies. (2) An Assessment of the Design Study of the 1 MeV Neutral Beam Injector Required for a Tandem Mirror Reactor. (3) The Significance of the Radial Plasma Size Measured in Units of Ion Gyroradii in Tandem Mirrors and Field Reversed Mirrors. (4) Producing Field Reversed Mirror Plasmas by Methods used in Field Reversed Theta Pinch. (5) RF Stoppering of Mirror Confined Plasma.

Mirror reactor surface study

Energy Technology Data Exchange (ETDEWEB)

Hunt, A. L.; Damm, C. C.; Futch, A. H.; Hiskes, J. R.; Meisenheimer, R. G.; Moir, R. W.; Simonen, T. C.; Stallard, B. W.; Taylor, C. E.

1976-09-01

A general survey is presented of surface-related phenomena associated with the following mirror reactor elements: plasma first wall, ion sources, neutral beams, director converters, vacuum systems, and plasma diagnostics. A discussion of surface phenomena in possible abnormal reactor operation is included. Several studies which appear to merit immediate attention and which are essential to the development of mirror reactors are abstracted from the list of recommended areas for surface work. The appendix contains a discussion of the fundamentals of particle/surface interactions. The interactions surveyed are backscattering, thermal desorption, sputtering, diffusion, particle ranges in solids, and surface spectroscopic methods. A bibliography lists references in a number of categories pertinent to mirror reactors. Several complete published and unpublished reports on surface aspects of current mirror plasma experiments and reactor developments are also included.

Transmission X-ray mirror

International Nuclear Information System (INIS)

Lairson, B.M.; Bilderback, D.H.

1982-01-01

Transmission X-ray mirrors have been made from 400 A to 10 000 A thick soap films and have been shown to have novel properties. Using grazing angles of incidence, low energy X-rays were reflected from the front surface while more energetic X-rays were transmitted through the mirror largely unattenuated. A wide bandpass monochromator was made from a silicon carbide mirror followed by a soap film transmission mirror and operated in the white beam at the cornell High Energy Synchrotron Source (CHESS). Bandpasses of ΔE/E=12% to 18% were achieved at 13 keV with peak efficiencies estimated to be between 55% and 75%, respectively. Several wide angle scattering photographs of stretched polyethylene and a phospholipid were obtained in 10 s using an 18% bandpass. (orig.)

Mirror reactor surface study

International Nuclear Information System (INIS)

Hunt, A.L.; Damm, C.C.; Futch, A.H.; Hiskes, J.R.; Meisenheimer, R.G.; Moir, R.W.; Simonen, T.C.; Stallard, B.W.; Taylor, C.E.

1976-01-01

A general survey is presented of surface-related phenomena associated with the following mirror reactor elements: plasma first wall, ion sources, neutral beams, director converters, vacuum systems, and plasma diagnostics. A discussion of surface phenomena in possible abnormal reactor operation is included. Several studies which appear to merit immediate attention and which are essential to the development of mirror reactors are abstracted from the list of recommended areas for surface work. The appendix contains a discussion of the fundamentals of particle/surface interactions. The interactions surveyed are backscattering, thermal desorption, sputtering, diffusion, particle ranges in solids, and surface spectroscopic methods. A bibliography lists references in a number of categories pertinent to mirror reactors. Several complete published and unpublished reports on surface aspects of current mirror plasma experiments and reactor developments are also included

Introduction to tandem mirror physics

International Nuclear Information System (INIS)

Kesner, J.; Gerver, M.J.; Lane, B.G.; McVey, B.D.; Catto, P.J.; D'Ippolito, D.A.; Myra, J.R.

1983-09-01

This monograph, prepared jointly by the MIT Plasma Fusion Center Mirror Fusion group and SAI, Boulder, Colorado, presents a review of the development of mirror fusion theory from its conception some thirty years ago to the present. Pertinent historic experiments and their contribution are discussed to set the stage for a detailed analysis of current experiments and the problems which remain to be solved in bringing tandem mirror magnetic confinement fusion to fruition. In particular, Chapter III discusses in detail the equilibrium and stability questions which must be dealt with before tandem mirror reactors become feasible, while Chapters IV and V discuss some of the current machines and those under construction which will help to resolve critical issues in both physics and engineering whose solutions are necessary to the commercialization of tandem mirror fusion

LLL mirror fusion program: summary

International Nuclear Information System (INIS)

Fowler, T.K.

1977-01-01

During 1976, new Mirror Program plans have been laid out to take into account the significant advances during the last 18 months. The program is now focused on two new mirror concepts, field reversal and the tandem mirror, that can obtain high Q, defined as the ratio of fusion power output to the neutral-beam power injected to sustain the reaction. Theoretically, both concepts can attain Q = 5 or more, as compared to Q = 1 in previous mirror designs. Experimental planning for the next 5 years is complete in broad outline, and we are turning attention to what additional steps are necessary to reach our long-range goal of an experimental mirror reactor operating by 1990. Highlights of the events that have led to the above circumstance are listed, and experimental program plans are outlined

Wealth and the inflated self: class, entitlement, and narcissism.

Science.gov (United States)

Piff, Paul K

2014-01-01

Americans may be more narcissistic now than ever, but narcissism is not evenly distributed across social strata. Five studies demonstrated that higher social class is associated with increased entitlement and narcissism. Upper-class individuals reported greater psychological entitlement (Studies 1a, 1b, and 2) and narcissistic personality tendencies (Study 2), and they were more likely to behave in a narcissistic fashion by opting to look at themselves in a mirror (Study 3). Finally, inducing egalitarian values in upper-class participants decreased their narcissism to a level on par with their lower-class peers (Study 4). These findings offer novel evidence regarding the influence of social class on the self and highlight the importance of social stratification to understanding basic psychological processes.

REOSC Delivers the Best Astronomical Mirror in the World to ESO

Science.gov (United States)

1999-12-01

On December 14, 1999, REOSC , the Optical Department of the SAGEM Group , finished the polishing of the fourth 8.2-m main mirror for the Very Large Telescope (VLT) of the European Southern Observatory. The mirror was today delivered to ESO at a ceremony at the REOSC factory in Saint Pierre du Perray, just south of Paris. The precision of the form of the mirror that was achieved during the polishing process is 8.5 nanometer (1 nanometer = 1 millionth of a millimetre) over the optical surface. This exceptional value corresponds to an optical resolution (theoretical image sharpness) of 0.03 arcseconds in the visible spectrum. This corresponds to distinguishing two objects separated by only 15 cm at a distance of 1000 km and will allow to detect astronomical objects that are 10,000 million times fainter than what can be perceived with the unaided eye. This impressive measure of quality, achieved by the REOSC teams during much painstaking work, implies that this VLT mirror is the most accurate in the world. In fact, all four 8.2-m VLT main mirrors polished by REOSC are well within the very strict specifications set by ESO, but this is the best of them all. The celebration today is the successful highlight of a contract initiated more than ten years ago, during which REOSC has perfected new polishing and control techniques - innovations improved and developed in a unique workshop dedicated to these giant mirrors. These methods and means are directly applicable to the new generations of segmented mirrors that are now being developed for astronomy and space observations. They are, in this sense, at the foremost front of optical technology. REOSC, the Optical Department of the SAGEM Group , is specialised in the study and realisation of high-precision optics for astronomy, space, defence, science and industry. For earlier information about the work on the VLT mirrors, cf. ESO Press Release 15/95 (13 November 1995). The SAGEM Group is a French high-technology group. It

Advances in telescope mirror cleaning

Science.gov (United States)

Blanken, Maarten F.; Chopping, Alan K.; Dee, Kevin M.

2004-09-01

Metrology and cleaning techniques for telescope mirrors are generally well established. CO2 cleaning and water washing are mainly used. Water washing has proven to be the best method of removing oil and water stains and restoring the aluminium to nearly fresh values. The risk of water getting to unwanted places such as electronics or other optics prevents this method from being employed more often. Recently the Isaac Newton Group introduced a new cleaning technique for their telescope mirrors, which reduces the risks discussed above. This technique uses water vapour instead of water to wash the mirror. The advantage of this method is that the amount of water needed is drastically reduced. In addition the pressure of the vapour will blow away any large dust particles on the mirror and the temperature shock between the vapour and the mirror will help to de-bond the dust particles. Adding a soapy solution will help to clean oil and watermarks of the mirror. This paper describes the vapour cleaning method, tests that have been done and the overall findings.

Mirror fusion--fission hybrids

International Nuclear Information System (INIS)

Lee, J.D.

1978-01-01

The fusion-fission concept and the mirror fusion-fission hybrid program are outlined. Magnetic mirror fusion drivers and blankets for hybrid reactors are discussed. Results of system analyses are presented and a reference design is described

Spontaneous expression of mirror self-recognition in monkeys after learning precise visual-proprioceptive association for mirror images.

Science.gov (United States)

Chang, Liangtang; Zhang, Shikun; Poo, Mu-Ming; Gong, Neng

2017-03-21

Mirror self-recognition (MSR) is generally considered to be an intrinsic cognitive ability found only in humans and a few species of great apes. Rhesus monkeys do not spontaneously show MSR, but they have the ability to use a mirror as an instrument to find hidden objects. The mechanism underlying the transition from simple mirror use to MSR remains unclear. Here we show that rhesus monkeys could show MSR after learning precise visual-proprioceptive association for mirror images. We trained head-fixed monkeys on a chair in front of a mirror to touch with spatiotemporal precision a laser pointer light spot on an adjacent board that could only be seen in the mirror. After several weeks of training, when the same laser pointer light was projected to the monkey's face, a location not used in training, all three trained monkeys successfully touched the face area marked by the light spot in front of a mirror. All trained monkeys passed the standard face mark test for MSR both on the monkey chair and in their home cage. Importantly, distinct from untrained control monkeys, the trained monkeys showed typical mirror-induced self-directed behaviors in their home cage, such as using the mirror to explore normally unseen body parts. Thus, bodily self-consciousness may be a cognitive ability present in many more species than previously thought, and acquisition of precise visual-proprioceptive association for the images in the mirror is critical for revealing the MSR ability of the animal.

Where do mirror neurons come from?

Science.gov (United States)

Heyes, Cecilia

2010-03-01

Debates about the evolution of the 'mirror neuron system' imply that it is an adaptation for action understanding. Alternatively, mirror neurons may be a byproduct of associative learning. Here I argue that the adaptation and associative hypotheses both offer plausible accounts of the origin of mirror neurons, but the associative hypothesis has three advantages. First, it provides a straightforward, testable explanation for the differences between monkeys and humans that have led some researchers to question the existence of a mirror neuron system. Second, it is consistent with emerging evidence that mirror neurons contribute to a range of social cognitive functions, but do not play a dominant, specialised role in action understanding. Finally, the associative hypothesis is supported by recent data showing that, even in adulthood, the mirror neuron system can be transformed by sensorimotor learning. The associative account implies that mirror neurons come from sensorimotor experience, and that much of this experience is obtained through interaction with others. Therefore, if the associative account is correct, the mirror neuron system is a product, as well as a process, of social interaction. (c) 2009 Elsevier Ltd. All rights reserved.

Perceptions and attitudes of formative assessments in middle-school science classes

Science.gov (United States)

Chauncey, Penny Denyse

No Child Left Behind mandates utilizing summative assessment to measure schools' effectiveness. The problem is that summative assessment measures students' knowledge without depth of understanding. The goal of public education, however, is to prepare students to think critically at higher levels. The purpose of this study was to examine any difference between formative assessment incorporated in instruction as opposed to the usual, more summative methods in terms of attitudes and academic achievement of middle-school science students. Maslow's theory emphasizes that individuals must have basic needs met before they can advance to higher levels. Formative assessment enables students to master one level at a time. The research questions focused on whether statistically significant differences existed between classrooms using these two types of assessments on academic tests and an attitude survey. Using a quantitative quasi-experimental control-group design, data were obtained from a sample of 430 middle-school science students in 6 classes. One control and 2 experimental classes were assigned to each teacher. Results of the independent t tests revealed academic achievement was significantly greater for groups that utilized formative assessment. No significant difference in attitudes was noted. Recommendations include incorporating formative assessment results with the summative results. Findings from this study could contribute to positive social change by prompting educational stakeholders to examine local and state policies on curriculum as well as funding based on summative scores alone. Use of formative assessment can lead to improved academic success.

Graded Mirror Self-Recognition by Clark's Nutcrackers.

Science.gov (United States)

Clary, Dawson; Kelly, Debbie M

2016-11-04

The traditional 'mark test' has shown some large-brained species are capable of mirror self-recognition. During this test a mark is inconspicuously placed on an animal's body where it can only be seen with the aid of a mirror. If the animal increases the number of actions directed to the mark region when presented with a mirror, the animal is presumed to have recognized the mirror image as its reflection. However, the pass/fail nature of the mark test presupposes self-recognition exists in entirety or not at all. We developed a novel mirror-recognition task, to supplement the mark test, which revealed gradation in the self-recognition of Clark's nutcrackers, a large-brained corvid. To do so, nutcrackers cached food alone, observed by another nutcracker, or with a regular or blurry mirror. The nutcrackers suppressed caching with a regular mirror, a behavioural response to prevent cache theft by conspecifics, but did not suppress caching with a blurry mirror. Likewise, during the mark test, most nutcrackers made more self-directed actions to the mark with a blurry mirror than a regular mirror. Both results suggest self-recognition was more readily achieved with the blurry mirror and that self-recognition may be more broadly present among animals than currently thought.

Mirror neurons: from origin to function.

Science.gov (United States)

Cook, Richard; Bird, Geoffrey; Catmur, Caroline; Press, Clare; Heyes, Cecilia

2014-04-01

This article argues that mirror neurons originate in sensorimotor associative learning and therefore a new approach is needed to investigate their functions. Mirror neurons were discovered about 20 years ago in the monkey brain, and there is now evidence that they are also present in the human brain. The intriguing feature of many mirror neurons is that they fire not only when the animal is performing an action, such as grasping an object using a power grip, but also when the animal passively observes a similar action performed by another agent. It is widely believed that mirror neurons are a genetic adaptation for action understanding; that they were designed by evolution to fulfill a specific socio-cognitive function. In contrast, we argue that mirror neurons are forged by domain-general processes of associative learning in the course of individual development, and, although they may have psychological functions, they do not necessarily have a specific evolutionary purpose or adaptive function. The evidence supporting this view shows that (1) mirror neurons do not consistently encode action "goals"; (2) the contingency- and context-sensitive nature of associative learning explains the full range of mirror neuron properties; (3) human infants receive enough sensorimotor experience to support associative learning of mirror neurons ("wealth of the stimulus"); and (4) mirror neurons can be changed in radical ways by sensorimotor training. The associative account implies that reliable information about the function of mirror neurons can be obtained only by research based on developmental history, system-level theory, and careful experimentation.

GMTIFS: the adaptive optics beam steering mirror for the GMT integral-field spectrograph

Science.gov (United States)

Davies, J.; Bloxham, G.; Boz, R.; Bundy, D.; Espeland, B.; Fordham, B.; Hart, J.; Herrald, N.; Nielsen, J.; Sharp, R.; Vaccarella, A.; Vest, C.; Young, P. J.

2016-07-01

To achieve the high adaptive optics sky coverage necessary to allow the GMT Integral-Field Spectrograph (GMTIFS) to access key scientific targets, the on-instrument adaptive-optics wavefront-sensing (OIWFS) system must patrol the full 180 arcsecond diameter guide field passed to the instrument. The OIWFS uses a diffraction limited guide star as the fundamental pointing reference for the instrument. During an observation the offset between the science target and the guide star will change due to sources such as flexure, differential refraction and non-sidereal tracking rates. GMTIFS uses a beam steering mirror to set the initial offset between science target and guide star and also to correct for changes in offset. In order to reduce image motion from beam steering errors to those comparable to the AO system in the most stringent case, the beam steering mirror is set a requirement of less than 1 milliarcsecond RMS. This corresponds to a dynamic range for both actuators and sensors of better than 1/180,000. The GMTIFS beam steering mirror uses piezo-walk actuators and a combination of eddy current sensors and interferometric sensors to achieve this dynamic range and control. While the sensors are rated for cryogenic operation, the actuators are not. We report on the results of prototype testing of single actuators, with the sensors, on the bench and in a cryogenic environment. Specific failures of the system are explained and suspected reasons for them. A modified test jig is used to investigate the option of heating the actuator and we report the improved results. In addition to individual component testing, we built and tested a complete beam steering mirror assembly. Testing was conducted with a point source microscope, however controlling environmental conditions to less than 1 micron was challenging. The assembly testing investigated acquisition accuracy and if there was any un-sensed hysteresis in the system. Finally we present the revised beam steering mirror

Helically linked mirror arrangement

International Nuclear Information System (INIS)

Ranjan, P.

1986-08-01

A scheme is described for helical linking of mirror sections, which endeavors to combine the better features of toroidal and mirror devices by eliminating the longitudinal loss of mirror machines, having moderately high average β and steady state operation. This scheme is aimed at a device, with closed magnetic surfaces having rotational transform for equilibrium, one or more axisymmetric straight sections for reduced radial loss, a simple geometrical axis for the links and an overall positive magnetic well depth for stability. We start by describing several other attempts at linking of mirror sections, made both in the past and the present. Then a description of our helically linked mirror scheme is given. This example has three identical straight sections connected by three sections having helical geometric axes. A theoretical analysis of the magnetic field and single-particle orbits in them leads to the conclusion that most of the passing particles would be confined in the device and they would have orbits independent of pitch angle under certain conditions. Numerical results are presented, which agree well with the theoretical results as far as passing particle orbits are concerned

Multiple-mirror plasma confinement

International Nuclear Information System (INIS)

Lichtenberg, A.J.; Lieberman, M.A.; Logan, B.G.

1975-01-01

A large enhancement of the confinement time can be achieved in a straight system of multiple mirrors over an equal length uniform magnetic field. The scaling is diffusive rather than that of flow, thereby scaling the square of the system length rather than linear with system length. Probably the most economic mode of operation for a reactor occurs when lambda/M is approximately l/sub c/, where lambda is the mean free path, M the mirror ratio, and l/sub c/ the length between mirrors; but where the scale length of the mirror field l/sub m/ is much less than lambda. The axial confinement time has been calculated theoretically and numerically for all important parameter regimes, and confirmed experimentally. A typical reactor calculation gives Q/sub E/ = 2 for a 400 meter system with 3000 MW(e) output. The main concern of a multiple-mirror system is stability. Linked quadrupoles can achieve average minimum-B stabilization of flute modes, and experiments have demonstrated this stabilization. Localized instabilities at finite β and enhanced diffusion resulting from the distorted flux surfaces and possibly from turbulent higher order modes still remain to be investigated

Magnetic mirror fusion: status and prospects

International Nuclear Information System (INIS)

Post, R.F.

1980-01-01

Two improved mirror systems, the tandem mirror (TM) and the field-reversed mirror (FRM) are being intensively studied. The twin practical aims of these studies: to improve the economic prospects for mirror fusion power plants and to reduce the size and/or complexity of such plants relative to earlier approaches to magnetic fusion. While at the present time the program emphasis is still strongly oriented toward answering scientific questions, the emphasis is shifting as the data accumulates and as larger facilities - ones with a heavy technological and engineering orientation - are being prepared. The experimental and theoretical progress that led to the new look in mirror fusion research is briefly reviewed, the new TM and the FRM ideas are outlined, and the projected future course of mirror fusion research is discussed

Laser cleaning of ITER's diagnostic mirrors

Science.gov (United States)

Skinner, C. H.; Gentile, C. A.; Doerner, R.

2012-10-01

Practical methods to clean ITER's diagnostic mirrors and restore reflectivity will be critical to ITER's plasma operations. We report on laser cleaning of single crystal molybdenum mirrors coated with either carbon or beryllium films 150 - 420 nm thick. A 1.06 μm Nd laser system provided 220 ns pulses at 8 kHz with typical power densities of 1-2 J/cm^2. The laser beam was fiber optically coupled to a scanner suitable for tokamak applications. The efficacy of mirror cleaning was assessed with a new technique that combines microscopic imaging and reflectivity measurements [1]. The method is suitable for hazardous materials such as beryllium as the mirrors remain sealed in a vacuum chamber. Excellent restoration of reflectivity for the carbon coated Mo mirrors was observed after laser scanning under vacuum conditions. For the beryllium coated mirrors restoration of reflectivity has so far been incomplete and modeling indicates that a shorter duration laser pulse is needed. No damage of the molybdenum mirror substrates was observed.[4pt][1] C.H. Skinner et al., Rev. Sci. Instrum. at press.

Mirror image agnosia.

Science.gov (United States)

Chandra, Sadanandavalli Retnaswami; Issac, Thomas Gregor

2014-10-01

Gnosis is a modality-specific ability to access semantic knowledge of an object or stimulus in the presence of normal perception. Failure of this is agnosia or disorder of recognition. It can be highly selective within a mode. self-images are different from others as none has seen one's own image except in reflection. Failure to recognize this image can be labeled as mirror image agnosia or Prosopagnosia for reflected self-image. Whereas mirror agnosia is a well-recognized situation where the person while looking at reflected images of other objects in the mirror he imagines that the objects are in fact inside the mirror and not outside. Five patients, four females, and one male presented with failure to recognize reflected self-image, resulting in patients conversing with the image as a friend, fighting because the person in mirror is wearing her nose stud, suspecting the reflected self-image to be an intruder; but did not have prosopagnosia for others faces, non living objects on self and also apraxias except dressing apraxia in one patient. This phenomena is new to our knowledge. Mirror image agnosia is an unique phenomena which is seen in patients with parietal lobe atrophy without specificity to a category of dementing illness and seems to disappear as disease advances. Reflected self-images probably have a specific neural substrate that gets affected very early in posterior dementias specially the ones which predominantly affect the right side. At that phase most patients are mistaken as suffering from psychiatric disorder as cognition is moderately preserved. As disease becomes more widespread this symptom becomes masked. A high degree of suspicion and proper assessment might help physicians to recognize the organic cause of the symptom so that early therapeutic interventions can be initiated. Further assessment of the symptom with FMRI and PET scan is likely to solve the mystery of how brain handles reflected self-images. A new observation involving failure

[Mirror, mirror of the wall: mirror therapy in the treatment of phantom limbs and phantom limb pain].

Science.gov (United States)

Casale, Roberto; Furnari, Anna; Lamberti, Raul Coelho; Kouloulas, Efthimios; Hagenberg, Annegret; Mallik, Maryam

2015-01-01

Phantom limb and phantom limb pain control are pivotal points in the sequence of intervention to bring the amputee to functional autonomy. The alterations of perception and sensation, the pain of the residual limb and the phantom limb are therefore aspects of amputation that should be taken into account in the "prise en charge" of these patients. Within the more advanced physical therapies to control phantom and phantom limb pain there is the use of mirrors (mirror therapy). This article willfocus on its use and on the possible side effects induced by the lack of patient selection and a conflict of body schema restoration through mirror therapy with concurrent prosthetic training and trauma acceptance. Advice on the need to select patients before treatment decisions, with regard to their psychological as well as clinical profile (including time since amputation and clinical setting), and the need to be aware of the possible adverse effects matching different and somehow conflicting therapeutic approaches, are put forward. Thus a coordinated sequence of diagnostic, prognostic and therapeutic procedures carried out by an interdisciplinary rehabilitation team that works globally on all patients' problems is fundamental in the management of amputees and phantom limb pain. Further studies and the development of a multidisciplinary network to study this and other applications of mirror therapy are needed.

Grating exchange system of independent mirror supported by floating rotary stage

Science.gov (United States)

Zhang, Jianhuan; Tao, Jin; Liu, Yan; Nan, Yan

2015-10-01

The performance of The Grating Exchange System can satisfy the Thirty Meter Telescope - TMT for astronomical observation WFOS index requirements and satisfy the requirement of accuracy in the grating exchange. It is used to install in the MOBIE and a key device of MOBIE. The Wide Field Optical Spectrograph (WFOS) is one of the three first-light observing capabilities selected by the TMT Science Advisory Committee. The Multi-Object Broadband Imaging Echellette (MOBIE) instrument design concept has been developed to address the WFOS requirements as described in the TMT Science-Based Requirements Document (SRD). The Grating Exchange System uses a new type of separate movement way of three grating devices and a mirror device. Three grating devices with a mirror are able to achieve independence movement. This kind of grating exchange system can effectively solve the problem that the volume of the grating change system is too large and that the installed space of MOBIE instruments is too limit. This system adopts the good stability, high precision of rotary stage - a kind of using air bearing (Air bearing is famous for its ultra-high precision, and can meet the optical accuracy requirement) and rotation positioning feedback gauge turntable to support grating device. And with a kind of device which can carry greater weight bracket fixed on the MOBIE instrument, with two sets of servo motor control rotary stage and the mirror device respectively. And we use the control program to realize the need of exercising of the grating device and the mirror device. Using the stress strain analysis software--SolidWorks for stress and strain analysis of this structure. And then checking the structure of the rationality and feasibility. And prove that this system can realize the positioning precision under different working conditions can meet the requirements of imaging optical grating diffraction efficiency and error by the calculation and optical performance analysis.

X-ray imaging with toroidal mirror

International Nuclear Information System (INIS)

Aoki, Sadao; Sakayanagi, Yoshimi

1978-01-01

X-ray imaging is made with a single toroidal mirror or two successive toroidal mirrors. Geometrical images at the Gaussian image plane are described by the ray trace. Application of a single toroidal mirror to small-angle scattering is presented. (author)

How science teachers balance religion and evolution in the science classroom: A case study of science classes in a Florida Public School District

Science.gov (United States)

Willems, Pierre Dominique

The purpose of this case study was to research how science teachers balance both religion and evolution in the science classroom with as little controversy as possible. In this study I attempted to provide some insight on how teachers are currently teaching evolution in their science classes in light of the religious beliefs of the students as well as their own. The case study was conducted in a school district in Florida where I attempted to answer the following questions: (a) How do science teachers in the Florida School District (FSD) approach the religion--evolution issue in preparing students for a career in a field of science? (b) How do science teachers in the FSD reconcile the subject of evolution with the religious views of their students? (c) How do science teachers in the FSD reconcile their own religious views with the teaching of evolution? (d) How do science teachers in the FSD perceive the relationship between religion and science? The data was collected through interviews with two high school teachers, and one middle school teacher, by observing each participant teach, by collecting site documents and by administering an exploratory survey to student volunteers. Analysis was conducted by open coding which produced four themes from which the research questions were answered and the survey answers were counted to produce the percentages displayed in the tables in chapter four. The teachers avoided discussion on religiously oriented questions or statements by the students and did not reveal their own religious orientation. The topic of microevolution appeared to reduce stress in the classroom environment, as opposed to addressing macroevolution.

Passivation coating for flexible substrate mirrors

Science.gov (United States)

Tracy, C. Edwin; Benson, David K.

1990-01-01

A protective diffusion barrier for metalized mirror structures is provided by a layer or coating of silicon nitride which is a very dense, transparent, dielectric material that is impervious to water, alkali, and other impurities and corrosive substances that typically attack the metal layers of mirrors and cause degradation of the mirrors' reflectivity. The silicon nitride layer can be deposited on the substrate before metal deposition thereon to stabilize the metal/substrate interface, and it can be deposited over the metal to encapsulate it and protect the metal from corrosion or other degradation. Mirrors coated with silicon nitride according to this invention can also be used as front surface mirrors. Also, the silver or other reflective metal layer on mirrors comprising thin, lightweight, flexible substrates of metal or polymer sheets coated with glassy layers can be protected with silicon nitride according to this invention.

[Mirror neurons].

Science.gov (United States)

Rubia Vila, Francisco José

2011-01-01

Mirror neurons were recently discovered in frontal brain areas of the monkey. They are activated when the animal makes a specific movement, but also when the animal observes the same movement in another animal. Some of them also respond to the emotional expression of other animals of the same species. These mirror neurons have also been found in humans. They respond to or "reflect" actions of other individuals in the brain and are thought to represent the basis for imitation and empathy and hence the neurobiological substrate for "theory of mind", the potential origin of language and the so-called moral instinct.

Constraints on mirror models of dark matter from observable neutron-mirror neutron oscillation

Science.gov (United States)

Mohapatra, Rabindra N.; Nussinov, Shmuel

2018-01-01

The process of neutron-mirror neutron oscillation, motivated by symmetric mirror dark matter models, is governed by two parameters: n -n‧ mixing parameter δ and n -n‧ mass splitting Δ. For neutron mirror neutron oscillation to be observable, the splitting between their masses Δ must be small and current experiments lead to δ ≤ 2 ×10-27 GeV and Δ ≤10-24 GeV. We show that in mirror universe models where this process is observable, this small mass splitting constrains the way that one must implement asymmetric inflation to satisfy the limits of Big Bang Nucleosynthesis on the number of effective light degrees of freedom. In particular we find that if asymmetric inflation is implemented by inflaton decay to color or electroweak charged particles, the oscillation is unobservable. Also if one uses SM singlet fields for this purpose, they must be weakly coupled to the SM fields.

Mirror Fusion Test Facility (MFTF)

International Nuclear Information System (INIS)

Thomassen, K.I.

1978-01-01

A large, new Mirror Fusion Test Facility is under construction at LLL. Begun in FY78 it will be completed at the end of FY78 at a cost of $94.2M. This facility gives the mirror program the flexibility to explore mirror confinement principles at a signficant scale and advances the technology of large reactor-like devices. The role of MFTF in the LLL program is described here

The mirror neuron system: new frontiers.

Science.gov (United States)

Keysers, Christian; Fadiga, Luciano

2008-01-01

Since the discovery of mirror neurons, much effort has been invested into studying their location and properties in the human brain. Here we review these original findings and introduce the main topics of this special issue of Social Neuroscience. What does the mirror system code? How is the mirror system embedded into the mosaic of circuits that compose our brain? How does the mirror system contribute to communication, language and social interaction? Can the principle of mirror neurons be extended to emotions, sensations and thoughts? Papers using a wide range of methods, including single cell recordings, fMRI, TMS, EEG and psychophysics, collected in this special issue, start to give us some impressive answers.

Incorporating Earth Science into Other High School Science Classes

Science.gov (United States)

Manning, C. L. B.; Holzer, M.; Colson, M.; Courtier, A. M. B.; Jacobs, B. E.

2016-12-01

As states begin to review their standards, some adopt or adapt the NGSS and others write their own, many basing these on the Framework for K-12 Science Education. Both the NGSS and the Frameworks have an increased emphasis on Earth Science but many high school teachers are being asked to teach these standards in traditional Biology, Chemistry and Physics courses. At the Earth Educators Rendezvous, teachers, scientists, and science education researchers worked together to find the interconnections between the sciences using the NGSS and identified ways to reference the role of Earth Sciences in the other sciences during lectures, activities and laboratory assignments. Weaving Earth and Space sciences into the other curricular areas, the teams developed relevant problems for students to solve by focusing on using current issues, media stories, and community issues. These and other lessons and units of study will be presented along with other resources used by teachers to ensure students are gaining exposure and a deeper understanding of Earth and Space Science concepts.

Neoclassical resonant transport of a mirror cell

International Nuclear Information System (INIS)

Ito, T.; Katanuma, I.

2005-01-01

The neoclassical resonant plateau transport in a mirror cell is studied theoretically. The analytical expression for a non-square-well magnetic field is obtained. The analytical result is applied to the GAMMA10 tandem mirror [T. Cho, M. Yoshida, J. Kohagura et al., Phys. Rev. Lett. 94, 085002-1 (2005)], which consists of several mirror cells in it, and the confinement time due to the neoclassical resonant plateau transport is determined in each mirror cell. It is found that the neoclassical resonant transport of ions trapped in the nonaxisymmetric anchor mirror cell and transition mirror cells is significantly smaller than those trapped in the central cell

Evolution of the mirror machine

International Nuclear Information System (INIS)

Damm, C.C.

1983-01-01

The history of the magnetic-mirror approach to a fusion reactor is primarily the history of our understanding and control of several crucial physics issues, coupled with progress in the technology of heating and confining a reacting plasma. The basic requirement of an MHD-stable plasma equilibrium was achieved following the early introduction of minimum-B multipolar magnetic fields. In refined form, the same magnetic-well principle carries over to our present experiments and to reactor designs. The higher frequency microinstabilities, arising from the non-Maxwellian particle distributions inherent in mirror machines, have gradually come under control as theoretical prescriptions for distribution functions have been applied in the experiments. Even with stability, the classical plasma leakage through the mirrors posed a serious question for reactor viability until the principle of electrostatic axial stoppering was applied in the tandem mirror configuration. Experiments to test this principle successfully demonstrated the substantial improvement in confinement predicted. Concurrent with advances in mirror plasma physics, development of both high-power neutral beam injectors and high-speed vacuum pumping techniques has played a crucial role in ongoing experiments. Together with superconducting magnets, cryogenic pumping, and high-power radiofrequency heating, these technologies have evolved to a level that extrapolates readily to meet the requirements of a tandem mirror fusion reactor

Mirror neurons: functions, mechanisms and models.

Science.gov (United States)

Oztop, Erhan; Kawato, Mitsuo; Arbib, Michael A

2013-04-12

Mirror neurons for manipulation fire both when the animal manipulates an object in a specific way and when it sees another animal (or the experimenter) perform an action that is more or less similar. Such neurons were originally found in macaque monkeys, in the ventral premotor cortex, area F5 and later also in the inferior parietal lobule. Recent neuroimaging data indicate that the adult human brain is endowed with a "mirror neuron system," putatively containing mirror neurons and other neurons, for matching the observation and execution of actions. Mirror neurons may serve action recognition in monkeys as well as humans, whereas their putative role in imitation and language may be realized in human but not in monkey. This article shows the important role of computational models in providing sufficient and causal explanations for the observed phenomena involving mirror systems and the learning processes which form them, and underlines the need for additional circuitry to lift up the monkey mirror neuron circuit to sustain the posited cognitive functions attributed to the human mirror neuron system. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Language Use in a Multilingual Class: a Study of the Relation Between Bilingual Students' Languages and Their Meaning-Making in Science

Science.gov (United States)

Ünsal, Zeynep; Jakobson, Britt; Molander, Bengt-Olov; Wickman, Per-Olof

2017-04-01

In this study, we examine how bilingual students in elementary school use their languages and what this means for their meaning-making in science. The class was multilingual with students bilingual in different minority languages and the teacher monolingual in Swedish. The analysis is based on a pragmatic approach and the theory of translanguaging. The science content was electricity, and the teaching involved class instruction and hands-on activities in small groups. The findings of the study are divided into two categories, students' conversations with the teacher and student's conversations with each other. Since the class was multilingual, the class instruction was carried out in Swedish. Generally, when the conversations were characterised by an initiation, response and evaluation pattern, the students made meaning of the activities without any language limitations. However, when the students, during whole class instruction, were engaged in conversations where they had to argue, discuss and explain their ideas, their language repertoire in Swedish limited their possibilities to express themselves. During hands-on activities, students with the same minority language worked together and used both of their languages as resources. In some situations, the activities proceeded without any visible language limitations. In other situations, students' language repertoire limited their possibilities to make meaning of the activities despite being able to use both their languages. What the results mean for designing and conducting science lessons in a multilingual class is discussed.

Plasma confinement apparatus using solenoidal and mirror coils

Science.gov (United States)

Fowler, T. Kenneth; Condit, William C.

1979-01-01

A plasma confinement apparatus, wherein multiple magnetic mirror cells are linked by magnetic field lines inside of a solenoid with the mirroring regions for adjacent magnetic mirror cells each formed by a separate mirror coil inside of the solenoid. The magnetic mirror cells may be field reversed.

Mirror neurons and language in schizophrenia

OpenAIRE

Bendová, Marie

2016-01-01

Mirror neurons are a specific kind of visuomotor neurons that are involved in action execution and also in action perception. The mirror mechanism is linked to a variety of complex psychological functions such as social-cognitive functions and language. People with schizophrenia have often difficulties both in mirror neuron system and in language skills. In the first part of our research we studied the connectivity of mirror neuron areas (such as IFG, STG, PMC, SMC and so on) by fMRI in resti...

Class of the affine line is a zero divisor in the Grothendieck ring

OpenAIRE

Borisov, Lev

2014-01-01

We show that the class of the affine line is a zero divisor in the Grothendieck ring of algebraic varieties over complex numbers. The argument is based on the Pfaffian-Grassmannian double mirror correspondence.

3d N=2 mirror symmetry, pq-webs and monopole superpotentials

Energy Technology Data Exchange (ETDEWEB)

Benvenuti, Sergio [International School of Advanced Studies (SISSA),via Bonomea 265, 34136 Trieste (Italy); INFN, Sezione di Trieste,Trieste (Italy); Pasquetti, Sara [Dipartimento di Fisica, Università di Milano-Bicocca,I-20126 Milano (Italy)

2016-08-23

D3 branes stretching between webs of (p,q) 5branes provide an interesting class of 3dN=2 theories. For generic pq-webs however the low energy field theory is not known. We use 3d mirror symmetry and Type IIB S-duality to construct Abelian gauge theories corresponding to D3 branes ending on both sides of a pq-web made of many coincident NS5’s intersecting one D5. These theories contain chiral monopole operators in the superpotential and enjoy a non trivial pattern of global symmetry enhancements. In the special case of the pq-web with one D5 and one NS5, the 3d low energy SCFT admits three dual formulations. This triality can be applied locally inside bigger quiver gauge theories. We prove our statements using partial mirror symmetry à la Kapustin-Strassler, showing the equality of the S{sub b}{sup 3} partition functions and studying the quantum chiral rings.

Plasma confinement apparatus using solenoidal and mirror coils

International Nuclear Information System (INIS)

Fowler, T.K.; Condit, W.C.

1979-01-01

A plasma confinement apparatus is described, wherein multiple magnetic mirror cells are linked by magnetic field lines inside of a solenoid with the mirroring regions for adjacent magnetic mirror cells each formed by a separate mirror coil inside of the solenoid. The magnetic mirror cells may be field reversed

CeSiCò - a new technology for lightweight and cost effective space instruments structures and mirrors

Science.gov (United States)

Devilliers, Christophe; Krödel, Matthias

2017-11-01

Alcatel Alenia Space and ECM have jointly developed a new ceramic material to produce lightweight, stiff, stable and cost effective structures and mirrors for space instrument the CesicÒ. Its intrinsic properties, added to ample manufacturing capabilities allow to manufacture stiff and lightweight cost effective mirrors and structure for space instruments. Different scale 1 flight representative CesicÒ optical structures have been manufactured and successfully tested under very strong dynamic environment and cryogenic condition down to 30K CesicÒ is also envisaged for large and lightweight space telescopes mirrors, a large CesicÒ 1 meter class mirror with an area mass of less than 25 Kg/m2 has been sized again launch loads and WFE performance and manufactured. CesicÒ applicability for large focal plane have been demonstrated through different scale 1 breadboards. Based on these successful results, AlcatelAleniaSpace and ECM are now in position to propose for space this technology with new innovative concepts thanks to the CesicÒ manufacturing capabilities. CesicÒ has therefore been selected for the structure and mirrors parts of a flight instrument payload and the manufacturing of the flight hardware is already underway. An high temperature high gain lightweight antenna breadboard is also under manufacturing for Bepi colombo mission. CesicÒ is therefore a good candidate for future challenging space instruments and is currently proposed for Japan and US space projects.

Owning the body in the mirror: The effect of visual perspective and mirror view on the full-body illusion.

Science.gov (United States)

Preston, Catherine; Kuper-Smith, Benjamin J; Ehrsson, Henrik H

2015-12-17

Mirrors allow us to view our own body from a third-person (observer) perspective. However, how viewing ourselves through a mirror affects central body representations compared with true third-person perspective is not fully understood. Across a series of experiments, multisensory full-body illusions were used to modulate feelings of ownership over a mannequin body that was viewed from a third-person perspective through a mirror, from a third-person perspective without a mirror, and from a first-person perspective. In contrast to non-mirror third-person perspective, synchronously touching the participant's actual body and the mannequin body viewed in the mirror elicited strong feelings of ownership over the mannequin and increased physiological responses to the mannequin being threatened compared to the equivalent asynchronous (non-ownership) control condition. Subjective reports of ownership viewing the mannequin through a mirror were also statistically equivalent to those following the first-person perspective illusion. These findings suggest that mirrors have a special role for viewing the self. The results also support the importance of egocentric reference frames for body ownership and suggest that mirror reflections of one's own body are related to peripersonal space, which enables updating of central body representations.

Physics issues in mirror and tandem mirror systems

International Nuclear Information System (INIS)

Post, R.F.

1984-01-01

Over the years the study of the confinement of high temperature plasma in magnetic mirror systems has presented researchers with many unusual physics problems. Many of these issues are by now understood theoretically and documented experimentally. With the advent of the tandem mirror idea, some new issues have emerged and are now under intensive study. These include: (1) the generation and control of ambipolar confining potentials and their effect on axial confinement and, (2) the combined influence of nonaxisymmetric magnetic fields (used to ensure MHD stability) and electric magnetic particle drifts on radial transport. Physics considerations associated with these two categories of issues will be reviewed, including concepts for the control of radial transport, under study or proposed

Constraints on mirror models of dark matter from observable neutron-mirror neutron oscillation

Directory of Open Access Journals (Sweden)

Rabindra N. Mohapatra

2018-01-01

Full Text Available The process of neutron-mirror neutron oscillation, motivated by symmetric mirror dark matter models, is governed by two parameters: n−n′ mixing parameter δ and n−n′ mass splitting Δ. For neutron mirror neutron oscillation to be observable, the splitting between their masses Δ must be small and current experiments lead to δ≤2×10−27 GeV and Δ≤10−24 GeV. We show that in mirror universe models where this process is observable, this small mass splitting constrains the way that one must implement asymmetric inflation to satisfy the limits of Big Bang Nucleosynthesis on the number of effective light degrees of freedom. In particular we find that if asymmetric inflation is implemented by inflaton decay to color or electroweak charged particles, the oscillation is unobservable. Also if one uses SM singlet fields for this purpose, they must be weakly coupled to the SM fields.

The mirror neuron system : New frontiers

NARCIS (Netherlands)

Keysers, Christian; Fadiga, Luciano

2008-01-01

Since the discovery of mirror neurons, much effort has been invested into Studying their location and properties in the human brain. Here we review these original findings and introduce the Main topics of this special issue of Social Neuroscience. What does the mirror system code? How is the mirror

High School Class for Gifted Pupils in Physics and Sciences and Pupils' Skills Measured by Standard and Pisa Test

Science.gov (United States)

Djordjevic, G. S.; Pavlovic-Babic, D.

2010-01-01

The "High school class for students with special abilities in physics" was founded in Nis, Serbia (www.pmf.ni.ac.yu/f_odeljenje) in 2003. The basic aim of this project has been introducing a broadened curriculum of physics, mathematics, computer science, as well as chemistry and biology. Now, six years after establishing of this specialized class, and 3 years after the previous report, we present analyses of the pupils' skills in solving rather problem oriented test, as PISA test, and compare their results with the results of pupils who study under standard curricula. More precisely results are compared to the progress results of the pupils in a standard Grammar School and the corresponding classes of the Mathematical Gymnasiums in Nis. Analysis of achievement data should clarify what are benefits of introducing in school system track for gifted students. Additionally, item analysis helps in understanding and improvement of learning strategies' efficacy. We make some conclusions and remarks that may be useful for the future work that aims to increase pupils' intrinsic and instrumental motivation for physics and sciences, as well as to increase the efficacy of teaching physics and science.

Analytic solution for a quartic electron mirror

Energy Technology Data Exchange (ETDEWEB)

Straton, Jack C., E-mail: straton@pdx.edu

2015-01-15

A converging electron mirror can be used to compensate for spherical and chromatic aberrations in an electron microscope. This paper presents an analytical solution to a diode (two-electrode) electrostatic mirror including the next term beyond the known hyperbolic shape. The latter is a solution of the Laplace equation to second order in the variables perpendicular to and along the mirror's radius (z{sup 2}−r{sup 2}/2) to which we add a quartic term (kλz{sup 4}). The analytical solution is found in terms of Jacobi cosine-amplitude functions. We find that a mirror less concave than the hyperbolic profile is more sensitive to changes in mirror voltages and the contrary holds for the mirror more concave than the hyperbolic profile. - Highlights: • We find the analytical solution for electron mirrors whose curvature has z4 dependence added to the usual z{sup 2} – r{sup 2}/2 terms. • The resulting Jacobi cosine-amplitude function reduces to the well-known cosh solution in the limit where the new term is 0. • This quartic term gives a mirror designer additional flexibility for eliminating spherical and chromatic aberrations. • The possibility of using these analytical results to approximately model spherical tetrode mirrors close to axis is noted.

Sensorimotor learning configures the human mirror system.

Science.gov (United States)

Catmur, Caroline; Walsh, Vincent; Heyes, Cecilia

2007-09-04

Cells in the "mirror system" fire not only when an individual performs an action but also when one observes the same action performed by another agent [1-4]. The mirror system, found in premotor and parietal cortices of human and monkey brains, is thought to provide the foundation for social understanding and to enable the development of theory of mind and language [5-9]. However, it is unclear how mirror neurons acquire their mirror properties -- how they derive the information necessary to match observed with executed actions [10]. We address this by showing that it is possible to manipulate the selectivity of the human mirror system, and thereby make it operate as a countermirror system, by giving participants training to perform one action while observing another. Before this training, participants showed event-related muscle-specific responses to transcranial magnetic stimulation over motor cortex during observation of little- and index-finger movements [11-13]. After training, this normal mirror effect was reversed. These results indicate that the mirror properties of the mirror system are neither wholly innate [14] nor fixed once acquired; instead they develop through sensorimotor learning [15, 16]. Our findings indicate that the human mirror system is, to some extent, both a product and a process of social interaction.

A Research on the Primary Mirror Manipulator of Large Segmented-mirror Telescope

Science.gov (United States)

Zuo, H.

2012-09-01

Since Galileo firstly used the telescope to observe the sky 400 years ago, the aperture of the telescope has become larger and larger to observe the deeper universe, and the segmented-mirror telescope is becoming more and more popular with increasing aperture. In the early 21st century, a series of segmented-mirror telescopes have been constructed including the Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST) of China. LAMOST is a meridian reflecting Schmidt telescope, and the dimension of the primary mirror is about 6.7 m× 6 m, which is composed of 37 hexagonal sub-mirrors. However, a problem about the mirror installation appears with the increasing aperture. If there are hundreds of sub-mirrors in the telescope, it is a challenging job to mount and dismount them to the truss. This problem is discussed in this paper and a manipulator for the primary mirror of LAMOST is designed to perform the mount and dismount work. In chapter 1, all the segmented-mirror telescopes in the world are introduced and how the sub-mirrors of these telescopes are installed has been investigated. After comparing with the serial and the parallel robot, a serial robot manipulator proposal, which has several redundant degrees of freedom (DOFs), has been chosen from a series of design proposals. In chapter 2, the theoretical analysis has been carried out on the basis of the design proposal, which includes the forward kinematics and the inverse kinematics. Firstly the D-H coordinate is built according to the structure of the manipulator, so it is possible to obtain the end-effector position and orientation from the individual joint motion thanks to the forward kinematics. Because of the redundant DOFs of the manipulator, the inverse kinematics solution can be a very trick task, and the result may not be only, therefore a kind of simulation is carried out to get the numerical solution using ADAMS (Automatic Dynamic Analysis of Mechanical System). In the dynamics analysis the

Metamaterial mirrors in optoelectronic devices

KAUST Repository

Esfandyarpour, Majid; Garnett, Erik C.; Cui, Yi; McGehee, Michael D.; Brongersma, Mark L.

2014-01-01

The phase reversal that occurs when light is reflected from a metallic mirror produces a standing wave with reduced intensity near the reflective surface. This effect is highly undesirable in optoelectronic devices that use metal films as both electrical contacts and optical mirrors, because it dictates a minimum spacing between the metal and the underlying active semiconductor layers, therefore posing a fundamental limit to the overall thickness of the device. Here, we show that this challenge can be circumvented by using a metamaterial mirror whose reflection phase is tunable from that of a perfect electric mirror († = €) to that of a perfect magnetic mirror († = 0). This tunability in reflection phase can also be exploited to optimize the standing wave profile in planar devices to maximize light-matter interaction. Specifically, we show that light absorption and photocurrent generation in a sub-100 nm active semiconductor layer of a model solar cell can be enhanced by ∼20% over a broad spectral band. © 2014 Macmillan Publishers Limited.

Metamaterial mirrors in optoelectronic devices

KAUST Repository

Esfandyarpour, Majid

2014-06-22

The phase reversal that occurs when light is reflected from a metallic mirror produces a standing wave with reduced intensity near the reflective surface. This effect is highly undesirable in optoelectronic devices that use metal films as both electrical contacts and optical mirrors, because it dictates a minimum spacing between the metal and the underlying active semiconductor layers, therefore posing a fundamental limit to the overall thickness of the device. Here, we show that this challenge can be circumvented by using a metamaterial mirror whose reflection phase is tunable from that of a perfect electric mirror († = €) to that of a perfect magnetic mirror († = 0). This tunability in reflection phase can also be exploited to optimize the standing wave profile in planar devices to maximize light-matter interaction. Specifically, we show that light absorption and photocurrent generation in a sub-100 nm active semiconductor layer of a model solar cell can be enhanced by ∼20% over a broad spectral band. © 2014 Macmillan Publishers Limited.

Vertex algebras and mirror symmetry

International Nuclear Information System (INIS)

Borisov, L.A.

2001-01-01

Mirror Symmetry for Calabi-Yau hypersurfaces in toric varieties is by now well established. However, previous approaches to it did not uncover the underlying reason for mirror varieties to be mirror. We are able to calculate explicitly vertex algebras that correspond to holomorphic parts of A and B models of Calabi-Yau hypersurfaces and complete intersections in toric varieties. We establish the relation between these vertex algebras for mirror Calabi-Yau manifolds. This should eventually allow us to rewrite the whole story of toric mirror symmetry in the language of sheaves of vertex algebras. Our approach is purely algebraic and involves simple techniques from toric geometry and homological algebra, as well as some basic results of the theory of vertex algebras. Ideas of this paper may also be useful in other problems related to maps from curves to algebraic varieties.This paper could also be of interest to physicists, because it contains explicit description of holomorphic parts of A and B models of Calabi-Yau hypersurfaces and complete intersections in terms of free bosons and fermions. (orig.)

Case Studies of Interactive Whole-Class Teaching in Primary Science: Communicative Approach and Pedagogic Purposes

Science.gov (United States)

McMahon, Kendra

2012-01-01

By developing two case studies of expert teaching in action, this study aimed to develop knowledge of talk in whole-class teaching in UK primary science lessons and understand this in relation to both the teachers' interpretations and sociocultural theoretical frameworks. Lessons were observed and video-recorded and the teachers engaged in…

Mirror reactor studies

International Nuclear Information System (INIS)

Moir, R.W.; Barr, W.L.; Bender, D.J.

1977-01-01

Design studies of a fusion mirror reactor, a fusion-fission mirror reactor, and two small mirror reactors are summarized. The fusion reactor uses 150-keV neutral-beam injectors based on the acceleration of negative ions. The injectors provide over 1 GW of continuous power at an efficiency greater than 80%. The fusion reactor has three-stage, modularized, Venetian blind, plasma direct converter with a predicted efficiency of 59% and a new concept for removal of the lune-shaped blanket: a crane is brought between the two halves of the Yin-Yang magnet, which are separated by a float. The design has desirable features such as steady-state operation, minimal impurity problems, and low first-wall thermal stress. The major disadvantage is low Q resulting in high re-circulating power and hence high cost of electrical power. However, the direct capital cost per unit of gross electrical power is reasonable [$1000/kW(e)]. By contrast, the fusion-fission reactor design is not penalized by re-circulating power and uses relatively near-term fusion technology being developed for the fusion power program. New results are presented on the Th- 233 U and the U- 239 Pu fuel cycles. The purpose of this hybrid is fuel production, with projected costs at $55/g of Pu or $127/g of 233 U. Blanket and cooling system designs, including an emergency cooling system, by General Atomic Company, lead us to the opinion that the reactor can meet expected safety standards for licensing. The smallest mirror reactor having only a shield between the plasma and the coil is the 4.2-m long fusion engineering research facility (FERF) designed for material irradiation. The smallest mirror reactor having both a blanket and shield is the 7.5-m long experimental power reactor (EPR), which has both a fusion and a fusion-fission version. (author)

Mirror Objects in the Solar System?

International Nuclear Information System (INIS)

Silagadze, Z.K.

2002-01-01

This talk was given at the Tunguska-2001 international conference but it is not about the Tunguska event. Instead we tried to give some flavor of mirror matter, which is predicted to exist if parity is an unbroken symmetry of nature, to non-experts. The possible connection of the mirror matter ideas to the Tunguska phenomenon was indicated by Foot and Gninenko some time ago and was elaborated by Foot in the separate talk at this conference. If the mirror world interpretation of the Tunguska like events is indeed correct then the most fascinating (but very speculative) possibility is that some well known celestial bodies with strange properties are in fact made mostly from mirror matter, and so maybe the mirror world was discovered long ago and we just have not suspected this. (author)

"Adotta scienza e arte nella tua classe": The results of a successfully teaching project which combines science with art⋆

Science.gov (United States)

Giansanti, S.

2015-03-01

The project called Adotta scienza e arte nella tua classe ("Adopt Science and Art in your class"), on the interconnection between science and art, has been addressed to the Italian secondary middle and high school involving more than 200 teachers and about 2200 students. The main purpose of this project is to make the young students aware of the strong link between science and art is a unique cultural and interdisciplinary occasion. To reach this goal, the Adotta project asked students to produce an artwork inspired by the interpretation of a quotation among a hundred commented quotes by physicists, mathematicians, scientist, writers, artists, accompanied by an original short sentence written by students themselves. More than 1000 artworks have been produced and collected in two galleries on Facebook. From their analysis emerges the students' feeling about science, which is usually associated to human brain, based on mathematical laws and related to technological progress, but it is also a powerful tool that should be responsibly used. This project also valorizes teachers' role in scientific education through activities that encourage students to recognize science in every aspect of their lives.

A comparison of performance of lightweight mirrors

Science.gov (United States)

Cho, Myung K.; Richard, Ralph M.; Hileman, Edward A.

1990-01-01

Four lightweight solid contoured back mirror shapes (a double arch, a single arch, a modified single arch, and a double concave mirror) and a cellular sandwich lightweight meniscus mirror, have been considered for the primary mirror of the Space Infrared Telescope Facility (SIRTF). A parametric design study using these shapes for the SIRTF 40 inch primary mirror with a focal ratio f/2 is presented. Evaluations of the optical performance and fundamental frequency analyses are performed to compare relative merits of each mirror configuration. Included in these are structural, optical, and frequency analyses for (1) different back contour shapes, (2) different number and location of the support points, and (3) two gravity orientations (ZENITH and HORIZON positions). The finite element program NASTRAN is used to obtain the structural deflections of the optical surface. For wavefront error analysis, FRINGE and PCFRINGE programs are used to evaluate the optical performance. A scaling law relating the optical and structural performance for various mirror contoured back shapes is developed.

Phase-stepping optical profilometry of atom mirrors

International Nuclear Information System (INIS)

MacLaren, D A; Goldrein, H T; Holst, B; Allison, W

2003-01-01

Electrically deformed single crystal mirrors will be a vital part of a first generation of scanning helium microscope (SHeM). Optimized mirrors will be used to focus thermal energy helium atoms into a surface-sensitive, low-energy probe, with a resolution that depends upon the precise mirror shape. Here, we present surface profilometry measurements of a prototype atom mirror. A temporal phase-stepping Mach-Zender fibre interferometer is used to profile the mirror surface with an accuracy of a few tens of nanometres. Results are compared with the theory of small deflections of an elastic thin plate. Our experiments suggest that relatively simple apparatus can induce the mirror profiles required to demagnify a conventional helium source into a microprobe suitable for a SHeM. Use of elliptical boundary conditions in the clamping mechanism afford biaxial bending in the crystal whilst a simple double-electrode design is demonstrated to be capable of asymmetric control of the mirror deformation

Tandem mirror next step conceptual design

International Nuclear Information System (INIS)

Doggett, J.N.; Damm, C.C.; Bulmer, R.H.

1980-01-01

A study was made to define the features of the experimental mirror fusion device - The Tandem Mirror Next Step, or TMNS - that will bridge the gap between present mirror confinement experiments and a power-producing reactor. We outline the project goals, describe some initial device parameters, and relate the technological requirements to ongoing development programs

Minimal mirror twin Higgs

Energy Technology Data Exchange (ETDEWEB)

Barbieri, Riccardo [Institute of Theoretical Studies, ETH Zurich,CH-8092 Zurich (Switzerland); Scuola Normale Superiore,Piazza dei Cavalieri 7, 56126 Pisa (Italy); Hall, Lawrence J.; Harigaya, Keisuke [Department of Physics, University of California,Berkeley, California 94720 (United States); Theoretical Physics Group, Lawrence Berkeley National Laboratory,Berkeley, California 94720 (United States)

2016-11-29

In a Mirror Twin World with a maximally symmetric Higgs sector the little hierarchy of the Standard Model can be significantly mitigated, perhaps displacing the cutoff scale above the LHC reach. We show that consistency with observations requires that the Z{sub 2} parity exchanging the Standard Model with its mirror be broken in the Yukawa couplings. A minimal such effective field theory, with this sole Z{sub 2} breaking, can generate the Z{sub 2} breaking in the Higgs sector necessary for the Twin Higgs mechanism. The theory has constrained and correlated signals in Higgs decays, direct Dark Matter Detection and Dark Radiation, all within reach of foreseen experiments, over a region of parameter space where the fine-tuning for the electroweak scale is 10-50%. For dark matter, both mirror neutrons and a variety of self-interacting mirror atoms are considered. Neutrino mass signals and the effects of a possible additional Z{sub 2} breaking from the vacuum expectation values of B−L breaking fields are also discussed.

Magnetic mirrors: history, results, and future prospects

International Nuclear Information System (INIS)

Beklemishev, A.D.; Ivanov, A.A.; Kruglyakov, E.P.; Burdakov, A.V.; Ivanov, A.A.; Beklemishev, A.D.; Ivanov, A.A.; Burdakov, A.V.

2012-01-01

The evolution of open traps brought them from simple solenoids to highly sophisticated and huge tandem mirrors with quadrupole magnetic stabilizers. They tried to compete with toroidal devices using ambipolar confinement and thermal barriers, but were too late and failed, and are almost extinct. A side branch of open traps went for simplicity and good fast-ion confinement inherent in axially symmetric mirrors. Since simplicity means lower cost of construction and servicing, and lower engineering and materials demands, such type of traps might still have an edge. Axially symmetric mirrors at the Budker Institute of Nuclear Physics in Novosibirsk currently represent the front line of mirror research. We discuss recent experimental results from the multiple-mirror trap, GOL-3, and the gas-dynamic trap, GDT. The next step in this line of research is the GDMT program that will combine the GDT-style fast-ion-dominated central mirror with multiple-mirror end plugs. This superconducting device will be modular and built in stages. The first stage, GDMT-T, will be based on 5m, 7T superconducting solenoid (multiple-mirror plug of the full device). Its 3-year scientific program is oriented primarily on PMI studies.

A Human Mirror Neuron System for Language: Perspectives from Signed Languages of the Deaf

Science.gov (United States)

Knapp, Heather Patterson; Corina, David P.

2010-01-01

Language is proposed to have developed atop the human analog of the macaque mirror neuron system for action perception and production [Arbib M.A. 2005. From monkey-like action recognition to human language: An evolutionary framework for neurolinguistics (with commentaries and author's response). "Behavioral and Brain Sciences, 28", 105-167; Arbib…

Auditory-vocal mirroring in songbirds.

Science.gov (United States)

Mooney, Richard

2014-01-01

Mirror neurons are theorized to serve as a neural substrate for spoken language in humans, but the existence and functions of auditory-vocal mirror neurons in the human brain remain largely matters of speculation. Songbirds resemble humans in their capacity for vocal learning and depend on their learned songs to facilitate courtship and individual recognition. Recent neurophysiological studies have detected putative auditory-vocal mirror neurons in a sensorimotor region of the songbird's brain that plays an important role in expressive and receptive aspects of vocal communication. This review discusses the auditory and motor-related properties of these cells, considers their potential role on song learning and communication in relation to classical studies of birdsong, and points to the circuit and developmental mechanisms that may give rise to auditory-vocal mirroring in the songbird's brain.

Negotiating the Inquiry Question: A Comparison of Whole Class and Small Group Strategies in Grade Five Science Classrooms

Science.gov (United States)

Cavagnetto, Andy R.; Hand, Brian; Norton-Meier, Lori

2011-03-01

The purpose of this study is to examine the effect of two strategies for negotiating the question for exploration during science inquiry on student achievement and teachers' perceptions. The study is set in the context of the Science Writing Heuristic. The first strategy (small group) consisted of each group of four students negotiating a question for inquiry with the teacher while the second strategy (whole class) consisted of the entire class negotiating a single question for inquiry with the teacher. The study utilized a mixed-method approach. A quasi-experimental repeated measures design was used to determine the effect of strategy on student achievement and semi-structured teacher interviews were used to probe the question of teacher perceptions of the two strategies. Teacher observations were conducted using the Reformed Teaching Observation Protocol (RTOP) to check for variation in implementation of the two strategies. Iowa Test of Basic Skills Science (ITBSS) (2005 and 2006) and teacher/researcher developed unit exams (pre and post) were used as student achievement measures. No statistically significant differences were found among students in the two treatment groups on the ITBSS or unit exams. RTOP observations suggest that teacher implementation was consistent across the two treatment strategies. Teachers disclosed personal preferences for the two strategies, indicating the whole class treatment was easier to manage (at least at the beginning of the school year) as students gained experience with science inquiry and the associated increased responsibility. Possible mechanisms linking the two strategies, negotiated questions, and student outcomes are discussed.

Teaching Language and Content: Instructor Strategies in a Bilingual Science Class at a Chinese University

Science.gov (United States)

Liang, Xiaoping; Smith, Sara W.

2012-01-01

The present research analyzes instructional strategies used to integrate the learning of content and English as a foreign language in a bilingual physics class at a university in Shanghai, China. It examines how the instructor handles meaning and form of new English science vocabulary in concept-focused physics lectures and the strategies he used…

Mounting and Alignment of IXO Mirror Segments

Science.gov (United States)

Chan, Kai-Wing; Zhang, William; Evans, Tyler; McClelland, Ryan; Hong, Melinda; Mazzarella, James; Saha, Timo; Jalota, Lalit; Olsen, Lawrence; Byron, Glenn

2010-01-01

A suspension-mounting scheme is developed for the IXO (International X-ray Observatory) mirror segments in which the figure of the mirror segment is preserved in each stage of mounting. The mirror, first fixed on a thermally compatible strongback, is subsequently transported, aligned and transferred onto its mirror housing. In this paper, we shall outline the requirement, approaches, and recent progress of the suspension mount processes.

A generalized construction of mirror manifolds

International Nuclear Information System (INIS)

Berglund, P.; Huebsch, T.

1993-01-01

We generalize the known method for explicit construction of mirror pairs of (2,2)-superconformal field theories, using the formalism of Landau-Ginzburg orbifolds. Geometrically, these theories are realized as Calabi-Yau hypersurfaces in weighted projective spaces. This generalization makes it possible to construct the mirror partners of many manifolds for which the mirror was not previously known. (orig.)

Giant pandas failed to show mirror self-recognition.

Science.gov (United States)

Ma, Xiaozan; Jin, Yuan; Luo, Bo; Zhang, Guiquan; Wei, Rongping; Liu, Dingzhen

2015-05-01

Mirror self-recognition (MSR), i.e., the ability to recognize oneself in a mirror, is considered a potential index of self-recognition and the foundation of individual development. A wealth of literature on MSR is available for social animals, such as chimpanzees, Asian elephants and dolphins, yet little is known about MSR in solitary mammalian species. We aimed to evaluate whether the giant panda can recognize itself in the mirror, and whether this capacity varies with age. Thirty-four captive giant pandas (F:M = 18:16; juveniles, sub-adults and adults) were subjected to four mirror tests: covered mirror tests, open mirror tests, water mark control tests, and mark tests. The results showed that, though adult, sub-adult and juvenile pandas exposed to mirrors spent similar amounts of time in social mirror-directed behaviors (χ(2) = 0.719, P = 0.698), none of them used the mirror to touch the mark on their head, a self-directed behavior suggesting MSR. Individuals of all age groups initially displayed attacking, threatening, foot scraping and backwards walking behaviors when exposed to their self-images in the mirror. Our data indicate that, regardless of age, the giant pandas did not recognize their self-image in the mirror, but instead considered the image to be a conspecific. Our results add to the available information on mirror self-recognition in large mammals, provide new information on a solitary species, and will be useful for enclosure design and captive animal management.

Genetics Home Reference: congenital mirror movement disorder

Science.gov (United States)

... Health Conditions Congenital mirror movement disorder Congenital mirror movement disorder Printable PDF Open All Close All Enable ... view the expand/collapse boxes. Description Congenital mirror movement disorder is a condition in which intentional movements ...

Simultaneous correction of large low-order and high-order aberrations with a new deformable mirror technology

Science.gov (United States)

Rooms, F.; Camet, S.; Curis, J. F.

2010-02-01

A new technology of deformable mirror will be presented. Based on magnetic actuators, these deformable mirrors feature record strokes (more than +/- 45μm of astigmatism and focus correction) with an optimized temporal behavior. Furthermore, the development has been made in order to have a large density of actuators within a small clear aperture (typically 52 actuators within a diameter of 9.0mm). We will present the key benefits of this technology for vision science: simultaneous correction of low and high order aberrations, AO-SLO image without artifacts due to the membrane vibration, optimized control, etc. Using recent papers published by Doble, Thibos and Miller, we show the performances that can be achieved by various configurations using statistical approach. The typical distribution of wavefront aberrations (both the low order aberration (LOA) and high order aberration (HOA)) have been computed and the correction applied by the mirror. We compare two configurations of deformable mirrors (52 and 97 actuators) and highlight the influence of the number of actuators on the fitting error, the photon noise error and the effective bandwidth of correction.

Computer Science Professionals and Greek Library Science

Science.gov (United States)

Dendrinos, Markos N.

2008-01-01

This paper attempts to present the current state of computer science penetration into librarianship in terms of both workplace and education issues. The shift from material libraries into digital libraries is mirrored in the corresponding shift from librarians into information scientists. New library data and metadata, as well as new automated…

Latent class analysis of diagnostic science assessment data using Bayesian networks

Science.gov (United States)

Steedle, Jeffrey Thomas

2008-10-01

Diagnostic science assessments seek to draw inferences about student understanding by eliciting evidence about the mental models that underlie students' reasoning about physical systems. Measurement techniques for analyzing data from such assessments embody one of two contrasting assessment programs: learning progressions and facet-based assessments. Learning progressions assume that students have coherent theories that they apply systematically across different problem contexts. In contrast, the facet approach makes no such assumption, so students should not be expected to reason systematically across different problem contexts. A systematic comparison of these two approaches is of great practical value to assessment programs such as the National Assessment of Educational Progress as they seek to incorporate small clusters of related items in their tests for the purpose of measuring depth of understanding. This dissertation describes an investigation comparing learning progression and facet models. Data comprised student responses to small clusters of multiple-choice diagnostic science items focusing on narrow aspects of understanding of Newtonian mechanics. Latent class analysis was employed using Bayesian networks in order to model the relationship between students' science understanding and item responses. Separate models reflecting the assumptions of the learning progression and facet approaches were fit to the data. The technical qualities of inferences about student understanding resulting from the two models were compared in order to determine if either modeling approach was more appropriate. Specifically, models were compared on model-data fit, diagnostic reliability, diagnostic certainty, and predictive accuracy. In addition, the effects of test length were evaluated for both models in order to inform the number of items required to obtain adequately reliable latent class diagnoses. Lastly, changes in student understanding over time were studied with a

Kodak AMSD Mirror Development Program

Science.gov (United States)

Matthews, Gary; Dahl, Roger; Barrett, David; Bottom, John; Russell, Kevin (Technical Monitor)

2002-01-01

The Advanced Mirror System Demonstration Program is developing minor technology for the next generation optical systems. Many of these systems will require extremely lightweight and stable optics due to the overall size of the primary mirror. These segmented, deployable systems require new technology that AMSD is developing. The on-going AMSD program is a critical enabler for Next Generation Space Telescope (NGST) which will start in 2002. The status of Kodak's AMSD mirror and future plans will be discussed with respect to the NGST program.

Mirror reactor studies

International Nuclear Information System (INIS)

Moir, R.W.; Barr, W.L.; Bender, D.J.

1976-01-01

Design studies of a fusion mirror reactor, a fusion-fission mirror reactor, and two small mirror reactors are summarized. The fusion reactor uses 150-keV neutral-beam injectors based on the acceleration of negative ions. The injectors provide over 1 GW of continuous power at an efficiency greater than 80 percent. The fusion reactor has three-stage, modularized, Venetian blind, plasma direct converter with a predicted efficiency of 59 percent and a new concept for removal of the lune-shaped blanket: a crane is brought between the two halves of the Yin-Yang magnet, which are separated by a float. The design has desirable features such as steady-state operation, minimal impurity problems, and low first-wall thermal stress. The major disadvantage is low Q resulting in high recirculating power and hence high cost of electrical power. However, the direct capital cost per unit of gross electrical power is reasonable [$1000/kW(e)

Effects of Brain-Based Learning Approach on Students' Motivation and Attitudes Levels in Science Class

Science.gov (United States)

Akyurek, Erkan; Afacan, Ozlem

2013-01-01

The purpose of the study was to examine the effect of brain-based learning approach on attitudes and motivation levels in 8th grade students' science classes. The main reason for examining attitudes and motivation levels, the effect of the short-term motivation, attitude shows the long-term effect. The pre/post-test control group research model…

Imitation, mirror neurons and autism.

Science.gov (United States)

Williams, J H; Whiten, A; Suddendorf, T; Perrett, D I

2001-06-01

Various deficits in the cognitive functioning of people with autism have been documented in recent years but these provide only partial explanations for the condition. We focus instead on an imitative disturbance involving difficulties both in copying actions and in inhibiting more stereotyped mimicking, such as echolalia. A candidate for the neural basis of this disturbance may be found in a recently discovered class of neurons in frontal cortex, 'mirror neurons' (MNs). These neurons show activity in relation both to specific actions performed by self and matching actions performed by others, providing a potential bridge between minds. MN systems exist in primates without imitative and 'theory of mind' abilities and we suggest that in order for them to have become utilized to perform social cognitive functions, sophisticated cortical neuronal systems have evolved in which MNs function as key elements. Early developmental failures of MN systems are likely to result in a consequent cascade of developmental impairments characterised by the clinical syndrome of autism.

Auditory–vocal mirroring in songbirds

Science.gov (United States)

Mooney, Richard

2014-01-01

Mirror neurons are theorized to serve as a neural substrate for spoken language in humans, but the existence and functions of auditory–vocal mirror neurons in the human brain remain largely matters of speculation. Songbirds resemble humans in their capacity for vocal learning and depend on their learned songs to facilitate courtship and individual recognition. Recent neurophysiological studies have detected putative auditory–vocal mirror neurons in a sensorimotor region of the songbird's brain that plays an important role in expressive and receptive aspects of vocal communication. This review discusses the auditory and motor-related properties of these cells, considers their potential role on song learning and communication in relation to classical studies of birdsong, and points to the circuit and developmental mechanisms that may give rise to auditory–vocal mirroring in the songbird's brain. PMID:24778375

Light-weight spherical mirrors for Cherenkov detectors

CERN Document Server

Cisbani, E; Colilli, S; Crateri, R; Cusanno, F; De Leo, R; Fratoni, R; Frullani, S; Garibaldi, F; Giuliani, F; Gricia, M; Iodice, M; Iommi, R; Lagamba, L; Lucentini, M; Mostarda, A; Nappi, E; Pierangeli, L; Santavenere, F; Urciuoli, G M; Vernin, P

2003-01-01

Light-weight spherical mirrors have been appositely designed and built for the gas threshold Cherenkov detectors of the two Hall A spectrometers. The mirrors are made of a 1 mm thick aluminized plexiglass sheet, reinforced by a rigid backing consisting of a phenolic honeycomb sandwiched between two carbon fiber mats epoxy glued. The produced mirrors have a thickness equivalent to 0.55% of radiation length, and an optical slope error of about 5.5 mrad. These characteristics make these mirrors suitable for the implementation in Cherenkov threshold detectors. Ways to improve the mirror features are also discussed in view of their possible employment in RICH detectors.

Mirror fusion reactor design

International Nuclear Information System (INIS)

Neef, W.S. Jr.; Carlson, G.A.

1979-01-01

Recent conceptual reactor designs based on mirror confinement are described. Four components of mirror reactors for which materials considerations and structural mechanics analysis must play an important role in successful design are discussed. The reactor components are: (a) first-wall and thermal conversion blanket, (b) superconducting magnets and their force restraining structure, (c) neutral beam injectors, and (d) plasma direct energy converters

Doubling the Performance-Cost Ratio of PV by Using Cheap Mirrors - a Secondary School Project

NARCIS (Netherlands)

Breejen, H.; van Herwaarden, S.; Keijsers, B.; van Dijk, V.A.P.; van Sark, W.G.J.H.M.|info:eu-repo/dai/nl/074628526

2007-01-01

Reduction of cost is a major issue in the photovoltaics field. We have addressed this issue in a secondaryschool science project by considering the use of cheap mirrors in combination with solar panels, for application in developing countries. We have confirmed that it is possible to increase the

Mirror Station for studies of the protection of diagnostic mirrors from impurity contamination in ITER: Design and first results

International Nuclear Information System (INIS)

Litnovsky, Andrey; Krasikov, Yuri; Kotov, Vladislav; Matveeva, Maria; Panin, Anatoly; Vera, Liliana; Buzi, Luxherta; Neubauer, Olaf; Biel, Wolfgang; Nicolai, Dirk; Mertens, Philippe; Linsmeier, Christian

2015-01-01

Highlights: • Paper is devoted to protection of diagnostic mirrors for ITER. • Modeling predicts suppression of impurity deposition on mirrors by using ducts. • The mirror tube system (Mirror Station) was built to validate the model. • The Mirror Station was exposed in TEXTOR. • The decrease of deposition in cylindrical ducts with fins cannot be confirmed. • All mirrors located in conical ducts preserved their reflectivity. - Abstract: Optical and laser-based diagnostics in ITER will use mirrors to transmit plasma radiation and laser light to the corresponding detectors and cameras. Mirrors will be sputtered by the fast plasma particles and contaminated by impurities leading to the degradation of the reflectivity and hampering the performance of corresponding diagnostics. Dedicated measures were proposed to minimize the impurity deposition comprising the use of shutters and fins inside diagnostic ducts to trap impurities on their way toward the mirror located in the end of these ducts. Modeling results predict at least 7-fold suppression of the deposition for the duct having four fins located at the distance of a half of a diameter from each other. The Mirror Station (MS) was designed to validate modeling predictions and to study the suppression of deposition inside of diagnostic ducts. The MS contained cylindrical and cone-shaped tubes of different lengths with smooth and shaped geometry of ducts. The MS was exposed in the midplane port of TEXTOR for about 3960 s of plasma operation. After exposure, no drastic suppression of deposition was observed in the cylindrical ducts with fins. In the conical tubes no deposition was detected outlining the advantages of a cone form.

Charged particle confinement in magnetic mirror

International Nuclear Information System (INIS)

Bora, D.; John, P.I.; Saxena, Y.C.; Varma, R.K.

1982-01-01

The behaviour of single charged particle trapped in a magnetic mirror has been investigated experimentally. The particle injected off axis and trapped in a magnetic mirror, leak out of the mirror with the leakage characterized by multiple decay times. The observed decay times are in good agreement with predictions of a ''wave mechanical like'' model by Varma, over a large range of relevant parameters. (author)

Study on the materials for mirrors and back mirror reflectors of thermonuclear reactors and their testing in Tore-Supra

International Nuclear Information System (INIS)

Schunke, B.; Voytsenya, V.; Gil, C.; Lipa, M.

2003-01-01

Plasma diagnostics using visible or ultra-violet or infra-red radiations require mirrors to probe the plasma. These mirrors have to sustain very hostile environment and despite that must maintain good optical properties. Mirror samples made of 3 different metals: copper, stainless steel and molybdenum have been designed and installed in Tore Supra tokamak and will be exposed to plasmas till mid 2004. This project will allow fusion engineers to assess the impact of plasma ion bombardment on mirror reflectivity. Optical properties and parameters concerning the surface state of the samples have been measured before the installation in Tore Supra and are presented in the paper. Simulations with a Monte-Carlo code predict the particle flux and spectra near the samples. A specific back mirror reflector has been designed to probe mirror reflectivity changes. (A.C.)

Plasma impact on diagnostic mirrors in JET

OpenAIRE

A. Garcia-Carrasco; P. Petersson; M. Rubel; A. Widdowson; E. Fortuna-Zalesna; S. Jachmich; M. Brix; L. Marot

2017-01-01

Metallic mirrors will be essential components of all optical systems for plasma diagnosis in ITER. This contribution provides a comprehensive account on plasma impact on diagnostic mirrors in JET with the ITER-Like Wall. Specimens from the First Mirror Test and the lithium-beam diagnostic have been studied by spectrophotometry, ion beam analysis and electron microscopy. Test mirrors made of molybdenum were retrieved from the main chamber and the divertor after exposure to the 2013–2014 experi...

A Conceptual Mirror

DEFF Research Database (Denmark)

Badie, Farshad

2017-01-01

The multilevel interactions between a mentor and her/his learner could exchange various conceptions between them that are supported by their own conceptualisations. Producing the own realisation of a world and developing it in the context of interactions could be said to be the most valuable prod...... will analyse the logical dependencies between learner and men- tor and will check their reflectional symmetrical relationship in a conceptual mirror. The conceptual mirror is a phenomenon that represents the meeting point of the mentor’s and the learner’s conceptual knowledge....

Mirror symmetry and loop operators

Energy Technology Data Exchange (ETDEWEB)

Assel, Benjamin [Department of Mathematics, King’s College London,The Strand, London WC2R 2LS (United Kingdom); Gomis, Jaume [Perimeter Institute for Theoretical Physics,Waterloo, Ontario, N2L 2Y5 (Canada)

2015-11-09

Wilson loops in gauge theories pose a fundamental challenge for dualities. Wilson loops are labeled by a representation of the gauge group and should map under duality to loop operators labeled by the same data, yet generically, dual theories have completely different gauge groups. In this paper we resolve this conundrum for three dimensional mirror symmetry. We show that Wilson loops are exchanged under mirror symmetry with Vortex loop operators, whose microscopic definition in terms of a supersymmetric quantum mechanics coupled to the theory encode in a non-trivial way a representation of the original gauge group, despite that the gauge groups of mirror theories can be radically different. Our predictions for the mirror map, which we derive guided by branes in string theory, are confirmed by the computation of the exact expectation value of Wilson and Vortex loop operators on the three-sphere.

Mirror fusion test facility

International Nuclear Information System (INIS)

Post, R.F.

1978-01-01

The MFTF is a large new mirror facility under construction at Livermore for completion in 1981--82. It represents a scaleup, by a factor of 50 in plasma volume, a factor of 5 or more in ion energy, and a factor of 4 in magnetic field intensity over the Livermore 2XIIB experiment. Its magnet, employing superconducting NbTi windings, is of Yin-Yang form and will weigh 200 tons. MFTF will be driven by neutral beams of two levels of current and energy: 1000 amperes of 20 keV (accelerating potential) pulsed beams for plasma startup; 750 amperes of 80 keV beams of 0.5 second duration for temperature buildup and plasma sustainment. Two operating modes for MFTF are envisaged: The first is operation as a conventional mirror cell with n/sup tau/ approximately equal to 10 12 cm -3 sec, W/sub i/ = 50 keV, where the emphasis will be on studying the physics of mirror cells, particularly the issues of improved techniques of stabilization against ion cyclotron modes and of maximization of the electron temperature. The second possible mode is the further study of the Field Reversed Mirror idea, using high current neutral beams to sustain the field-reversed state. Anticipating success in the coming Livermore Tandem Mirror Experiment (TMX) MFTF has been oriented so that it could comprise one end cell of a scaled up TM experiment. Also, if MFTF were to succeed in achieving a FR state it could serve as an essentially full-sized physics prototype of one cell of a FRM fusion power plant

ANALYZE THE KNOWLEDGE INQUIRY SCIENCE PHYSICS TEACHER CANDIDATES WITH ESSENCE INQUIRY SCIENCE TEST INSTRUMENT OPTIKA GEOMETRY

Directory of Open Access Journals (Sweden)

Wawan Bunawan

2013-06-01

Full Text Available The objective in this research to explore the relationship between ability of the knowledge essential features inquiry science and their reasons underlying sense of scientific inquiry for physics teacher candidates on content geometrical optics. The essential features of inquiry science are components that should arise during the learning process subject matter of geometrical optics reflectance of light on a flat mirror, the reflection of light on curved mirrors and refraction of light at the lens. Five of essential features inquiry science adopted from assessment system developed by the National Research Council. Content geometrical optics developed from an analysis of a college syllabus material. Based on the study of the essential features of inquiry and content develop the multiple choice diagnostic test three tier. Data were taken from the students who are taking courses in optics and wave from one the LPTK in North Sumatra totaled 38 students. Instruments showed Cronbach alpha reliability of 0.67 to test the essential features of inquiry science and 0.61 to there as on geometrical optics science inquiry.

Mirror neurons and their clinical relevance.

Science.gov (United States)

Rizzolatti, Giacomo; Fabbri-Destro, Maddalena; Cattaneo, Luigi

2009-01-01

One of the most exciting events in neurosciences over the past few years has been the discovery of a mechanism that unifies action perception and action execution. The essence of this 'mirror' mechanism is as follows: whenever individuals observe an action being done by someone else, a set of neurons that code for that action is activated in the observers' motor system. Since the observers are aware of the outcome of their motor acts, they also understand what the other individual is doing without the need for intermediate cognitive mediation. In this Review, after discussing the most pertinent data concerning the mirror mechanism, we examine the clinical relevance of this mechanism. We first discuss the relationship between mirror mechanism impairment and some core symptoms of autism. We then outline the theoretical principles of neurorehabilitation strategies based on the mirror mechanism. We conclude by examining the relationship between the mirror mechanism and some features of the environmental dependency syndromes.

Cavity-mirror degradation in the deep-UV FEL

Energy Technology Data Exchange (ETDEWEB)

Yamada, K.; Yamazaki, T.; Sei, N. [Electrotechnical Lab., Ibaraki (Japan)] [and others

1995-12-31

It is known that the degradation of dielectric multilayer mirrors used in short wavelength free-electron lasers (FELs) is caused by the carbon contamination on the mirror surface and the defects inside the dielectrics. We reported last year that the degraded dielectric multilayer mirrors can be repaired with both surface treatment by RF-induced oxygen plasma and thermal annealing. However, such a mirror degradation is still one of the most critical issues in the deep ultraviolet (UV) FELs, because the fundamental undulator radiation resonating in the laser cavity, the intensity of which is much higher than that of higher harmonics, can be sufficiently energetic to cause the mirror degradation through photochemical reactions. We are investigating the mirror degradation mainly in the deep UV region down to 240 nm. The experimental results will be shown. The mirror degradation mechanism will be discussed.

Plasma impact on diagnostic mirrors in JET

Directory of Open Access Journals (Sweden)

A. Garcia-Carrasco

2017-08-01

Full Text Available Metallic mirrors will be essential components of all optical systems for plasma diagnosis in ITER. This contribution provides a comprehensive account on plasma impact on diagnostic mirrors in JET with the ITER-Like Wall. Specimens from the First Mirror Test and the lithium-beam diagnostic have been studied by spectrophotometry, ion beam analysis and electron microscopy. Test mirrors made of molybdenum were retrieved from the main chamber and the divertor after exposure to the 2013–2014 experimental campaign. In the main chamber, only mirrors located at the entrance of the carrier lost reflectivity (Be deposition, while those located deeper in the carrier were only slightly affected. The performance of mirrors in the JET divertor was strongly degraded by deposition of beryllium, tungsten and other species. Mirrors from the lithium-beam diagnostic have been studied for the first time. Gold coatings were severely damaged by intense arcing. As a consequence, material mixing of the gold layer with the stainless steel substrate occurred. Total reflectivity dropped from over 90% to less than 60%, i.e. to the level typical for stainless steel.

LUTE primary mirror materials and design study report

Science.gov (United States)

Ruthven, Greg

1993-02-01

The major objective of the Lunar Ultraviolet Telescope Experiment (LUTE) Primary Mirror Materials and Design Study is to investigate the feasibility of the LUTE telescope primary mirror. A systematic approach to accomplish this key goal was taken by first understanding the optical, thermal, and structural requirements and then deriving the critical primary mirror-level requirements for ground testing, launch, and lunar operations. After summarizing the results in those requirements which drove the selection of material and the design for the primary mirror are discussed. Most important of these are the optical design which was assumed to be the MSFC baseline (i.e. 3 mirror optical system), telescope wavefront error (WFE) allocations, the telescope weight budget, and the LUTE operational temperature ranges. Mechanical load levels, reflectance and microroughness issues, and options for the LUTE metering structure were discussed and an outline for the LUTE telescope sub-system design specification was initiated. The primary mirror analysis and results are presented. The six material substrate candidates are discussed and four distinct mirror geometries which are considered are shown. With these materials and configurations together with varying the location of the mirror support points, a total of 42 possible primary mirror designs resulted. The polishability of each substrate candidate was investigated and a usage history of 0.5 meter and larger precision cryogenic mirrors (the operational low end LUTE temperature of 60 K is the reason we feel a survey of cryogenic mirrors is appropriate) that were flown or tested are presented.

The spinning Kerr-black-hole-mirror bomb: A lower bound on the radius of the reflecting mirror

Science.gov (United States)

Hod, Shahar

2016-10-01

The intriguing superradiant amplification phenomenon allows an orbiting scalar field to extract rotational energy from a spinning Kerr black hole. Interestingly, the energy extraction rate can grow exponentially in time if the black-hole-field system is placed inside a reflecting mirror which prevents the field from radiating its energy to infinity. This composed Kerr-black-hole-scalar-field-mirror system, first designed by Press and Teukolsky, has attracted the attention of physicists over the last four decades. Previous numerical studies of this spinning black-hole bomb have revealed the interesting fact that the superradiant instability shuts down if the reflecting mirror is placed too close to the black-hole horizon. In the present study we use analytical techniques to explore the superradiant instability regime of this composed Kerr-black-hole-linearized-scalar-field-mirror system. In particular, it is proved that the lower bound rm/r+ >1/2 (√{ 1 +8M/r- } - 1) provides a necessary condition for the development of the exponentially growing superradiant instabilities in this composed physical system, where rm is the radius of the confining mirror and r± are the horizon radii of the spinning Kerr black hole. We further show that, in the linearized regime, this analytically derived lower bound on the radius of the confining mirror agrees with direct numerical computations of the superradiant instability spectrum which characterizes the spinning black-hole-mirror bomb.

The issues that class teachers encounter during application of science and technology teaching curriculum

Directory of Open Access Journals (Sweden)

Mustafa Ugras

2014-08-01

Full Text Available This study aimed at investigating the challenges class teachers face in the curriculum implementation and whether these challenges differ in relation to teachers’ gender, level of education, department they graduated from and teaching experience. For this purpose; a questionnaire was developed by the researcher. Items of the questionnaire were selected from the related literature and validated by a group of expert in the field. A pilot study was conducted to assess the clarity of the questionnaire items. The internal reliability of the final version of questionnaire was calculated by using Cronbach’s Alpha Formula and found be high (α=0.85. The participants of this research included 342 class teachers who were teaching 4th and 5th class in 57 different elementary schools in 2010-2011 academic years in Bingol and Diayrbakir cities. The results of the survey were considered by using SPSS packet program. In the analyzing of data obtained from this study, frequency, arithmetic average, t-test and variance analysis were used. From the obtained data, it was determined that the 4th and 5th class teachers encounter different problems in science and technology teaching program, especially in performance homework, sourcing and lesson time topics.

Standard specification for silvered flat glass mirror

CERN Document Server

American Society for Testing and Materials. Philadelphia

2008-01-01

1.1 This specification covers the requirements for silvered flat glass mirrors of rectangular shape supplied as cut sizes, stock sheets or as lehr ends and to which no further processing (such as edgework or other fabrication) has been done. 1.2 This specification covers the quality requirements of silvered annealed monolithic clear and tinted flat glass mirrors up to 6 mm (¼ in.) thick. The mirrors are intended to be used indoors for mirror glazing, for components of decorative accessories or for similar uses. 1.3 This specification does not address safety glazing materials nor requirements for mirror applications. Consult model building codes and other applicable standards for safety glazing applications. 1.4 Mirrors covered in this specification are not intended for use in environments where high humidity or airborne corrosion promoters, or both, are consistently present (such as swimming pool areas, ocean-going vessels, chemical laboratories and other corrosive environments). 1.5 The dimensional val...

Mirror neurons and imitation: a computationally guided review.

Science.gov (United States)

Oztop, Erhan; Kawato, Mitsuo; Arbib, Michael

2006-04-01

Neurophysiology reveals the properties of individual mirror neurons in the macaque while brain imaging reveals the presence of 'mirror systems' (not individual neurons) in the human. Current conceptual models attribute high level functions such as action understanding, imitation, and language to mirror neurons. However, only the first of these three functions is well-developed in monkeys. We thus distinguish current opinions (conceptual models) on mirror neuron function from more detailed computational models. We assess the strengths and weaknesses of current computational models in addressing the data and speculations on mirror neurons (macaque) and mirror systems (human). In particular, our mirror neuron system (MNS), mental state inference (MSI) and modular selection and identification for control (MOSAIC) models are analyzed in more detail. Conceptual models often overlook the computational requirements for posited functions, while too many computational models adopt the erroneous hypothesis that mirror neurons are interchangeable with imitation ability. Our meta-analysis underlines the gap between conceptual and computational models and points out the research effort required from both sides to reduce this gap.

Standard mirror fusion reactor design study

International Nuclear Information System (INIS)

Moir, R.W.

1978-01-01

This report covers the work of the Magnetic Fusion Energy Division's reactor study group during FY 1976 on the standard mirror reactor. The ''standard'' mirror reactor is characterized as a steady state, neutral beam sustained, D-T fusioning plasma confined by a Yin-Yang magnetic mirror field. The physics parameters are obtained from the same physics model that explains the 2XIIB experiment. The model assumes that the drift cyclotron loss cone mode occurs on the boundary of the plasma, and that it is stabilized by warm plasma with negligible energy investment. The result of the study was a workable mirror fusion power plant, steady-state blanket removal made relatively simple by open-ended geometry, and no impurity problem due to the positive plasma potential. The Q (fusion power/injected beam power) turns out to be only 1.1 because of loss out the ends from Coulomb collisions, i.e., classical losses. This low Q resulted in 77% of the gross electrical power being used to power the injectors, thereby causing the net power cost to be high. The low Q stimulated an intensive search for Q-enhancement concepts, resulting in the LLL reactor design effort turning to the field reversal mirror and the tandem mirror, each having Q of order 5

Responses of mirror neurons in area F5 to hand and tool grasping observation

Science.gov (United States)

Rochat, Magali J.; Caruana, Fausto; Jezzini, Ahmad; Escola, Ludovic; Intskirveli, Irakli; Grammont, Franck; Gallese, Vittorio; Rizzolatti, Giacomo

2010-01-01

Mirror neurons are a distinct class of neurons that discharge both during the execution of a motor act and during observation of the same or similar motor act performed by another individual. However, the extent to which mirror neurons coding a motor act with a specific goal (e.g., grasping) might also respond to the observation of a motor act having the same goal, but achieved with artificial effectors, is not yet established. In the present study, we addressed this issue by recording mirror neurons from the ventral premotor cortex (area F5) of two monkeys trained to grasp objects with pliers. Neuron activity was recorded during the observation and execution of grasping performed with the hand, with pliers and during observation of an experimenter spearing food with a stick. The results showed that virtually all neurons responding to the observation of hand grasping also responded to the observation of grasping with pliers and, many of them to the observation of spearing with a stick. However, the intensity and pattern of the response differed among conditions. Hand grasping observation determined the earliest and the strongest discharge, while pliers grasping and spearing observation triggered weaker responses at longer latencies. We conclude that F5 grasping mirror neurons respond to the observation of a family of stimuli leading to the same goal. However, the response pattern depends upon the similarity between the observed motor act and the one executed by the hand, the natural motor template. PMID:20577726

Understanding social reproduction: The recursive nature of structure and agency within a science class

Science.gov (United States)

Seiler, Gale A.

Schools and science classrooms within schools continue to contribute to social reproduction and to the disenfranchisement of inner city African American students though attempts have been made to remedy the situation through standards, high-stakes testing, and compensatory programs. Such reforms ignore the sociocultural, political, and economic contexts of the individual students in the schools they are impacting. They do not take into account the uniqueness and diversity of the learners in these settings and have not included the voices of the students. Another possibility was studied here; that of starting with the cultural capital of the learner rather than with external standards. In a non-required science course at a local high school two coteachers endeavored to enact a student-emergent curriculum as a way to foster student agency and to counteract the reproductive nature of schools. The class was examined as a field within multiple other fields. The dialectical relationship between structure and agency in the class was used to frame the analysis and the tension between them was examined at several levels through video and audio analysis. Structural and rational choice views of action were abandoned in favor of an understanding hinged upon strategies of action that actors construct from cultural toolkits in and through practice. In this setting the students and teachers co-constructed a class that can be described and characterized in certain ways yet contained many counter-examples and alternative characterizations. A continuum of successes and failures, agency and subjectivity can be found in the trends and counter-trends in the course. The contradictions were examined to portray the complexity of the interactions and the possibilities for agency within them.

Optical fabrication of lightweighted 3D printed mirrors

Science.gov (United States)

Herzog, Harrison; Segal, Jacob; Smith, Jeremy; Bates, Richard; Calis, Jacob; De La Torre, Alyssa; Kim, Dae Wook; Mici, Joni; Mireles, Jorge; Stubbs, David M.; Wicker, Ryan

2015-09-01

Direct Metal Laser Sintering (DMLS) and Electron Beam Melting (EBM) 3D printing technologies were utilized to create lightweight, optical grade mirrors out of AlSi10Mg aluminum and Ti6Al4V titanium alloys at the University of Arizona in Tucson. The mirror prototypes were polished to meet the λ/20 RMS and λ/4 P-V surface figure requirements. The intent of this project was to design topologically optimized mirrors that had a high specific stiffness and low surface displacement. Two models were designed using Altair Inspire software, and the mirrors had to endure the polishing process with the necessary stiffness to eliminate print-through. Mitigating porosity of the 3D printed mirror blanks was a challenge in the face of reconciling new printing technologies with traditional optical polishing methods. The prototypes underwent Hot Isostatic Press (HIP) and heat treatment to improve density, eliminate porosity, and relieve internal stresses. Metal 3D printing allows for nearly unlimited topological constraints on design and virtually eliminates the need for a machine shop when creating an optical quality mirror. This research can lead to an increase in mirror mounting support complexity in the manufacturing of lightweight mirrors and improve overall process efficiency. The project aspired to have many future applications of light weighted 3D printed mirrors, such as spaceflight. This paper covers the design/fab/polish/test of 3D printed mirrors, thermal/structural finite element analysis, and results.

Three mirror pairs of fermion families

International Nuclear Information System (INIS)

Montvay, I.

1988-01-01

A simple model with three mirror pairs of fermion families is considered which allows for a substantial mixing between the mirror fermion partners without conflicting with known phenomenology. (orig.)

Elliptically Bent X-ray Mirrors with Active Temperature Stabilization

International Nuclear Information System (INIS)

Yuan, Sheng; Church, Matthew; Yashchuk, Valeriy V.; Goldberg, Kenneth A.; Celestre, Rich; McKinney, Wayne R.; Kirschman, Jonathan; Morrison, Greg; Noll, Tino; Warwick, Tony; Padmore, Howard A.

2010-01-01

We present details of design of elliptically bent Kirkpatrick-Baez mirrors developed and successfully used at the Advanced Light Source for submicron focusing. A distinctive feature of the mirror design is an active temperature stabilization based on a Peltier element attached directly to the mirror body. The design and materials have been carefully optimized to provide high heat conductance between the mirror body and substrate. We describe the experimental procedures used when assembling and precisely shaping the mirrors, with special attention paid to laboratory testing of the mirror-temperature stabilization. For this purpose, the temperature dependence of the surface slope profile of a specially fabricated test mirror placed inside a temperature-controlled container was measured. We demonstrate that with active mirror-temperature stabilization, a change of the surrounding temperature by more than 3K does not noticeably affect the mirror figure. Without temperature stabilization, the surface slope changes by approximately 1.5 ?mu rad rms (primarily defocus) under the same conditions.

Elliptically Bent X-Ray Mirrors with Active Temperature Stabilization

International Nuclear Information System (INIS)

Yuan, S.; Church, M.; Yashchuk, V.V.; Celestre, R.S.; McKinney, W.R.; Morrison, G.; Warwick, T.; Padmore, H.A.; Goldberg, K.A.; Kirschman, J.; Noll, T.

2010-01-01

We present details of design of elliptically bent Kirkpatrick-Baez mirrors developed and successfully used at the advanced light source for submicron focusing. A distinctive feature of the mirror design is an active temperature stabilization based on a Peltier element attached directly to the mirror body. The design and materials have been carefully optimized to provide high heat conductance between the mirror body and substrate. We describe the experimental procedures used when assembling and precisely shaping the mirrors, with special attention paid to laboratory testing of the mirror-temperature stabilization. For this purpose, the temperature dependence of the surface slope profile of a specially fabricated test mirror placed inside a temperature-controlled container was measured. We demonstrate that with active mirror-temperature stabilization, a change of the surrounding temperature by more than 3 K does not noticeably affect the mirror figure. Without temperature stabilization, the rms slope error is changed by approximately 1.5 μrad (primarily defocus) under the same conditions

Tools for Implementing Science Practice in a Large Introductory Class

Science.gov (United States)

Prothero, W. A.

2008-12-01

Scientists must have in-depth background knowledge of their subject area and know where current knowledge can be advanced. They perform experiments that gather data to test new or existing theories, present their findings at meetings, publish their results, critically review the results of others, and respond to the reviews of their own work. In the context of a course, these activities correspond to learning the background material by listening to lectures or reading a text, formulating a problem, exploring data using student friendly data access and plotting software, giving brief talks to classmates in a small class or lab setting, writing a science paper or lab report, reviewing the writing of their peers, and receiving feedback (and grades) from their instructors and/or peers. These activities can be supported using course management software and online resources. The "LearningWithData" software system allows solid Earth (focused on plate tectonics) data exploration and plotting. Ocean data access, display, and plotting are also supported. Background material is delivered using animations and slide show type displays. Students are accountable for their learning through included homework assignments. Lab and small group activities provide support for data exploration and interpretation. Writing is most efficiently implemented using the "Calibrated Peer Review" method. This methodology is available at http://cpr.molsci.ucla.edu/. These methods have been successfully implemented in a large oceanography class at UCSB.

FMRI evidence of 'mirror' responses to geometric shapes.

Science.gov (United States)

Press, Clare; Catmur, Caroline; Cook, Richard; Widmann, Hannah; Heyes, Cecilia; Bird, Geoffrey

2012-01-01

Mirror neurons may be a genetic adaptation for social interaction. Alternatively, the associative hypothesis proposes that the development of mirror neurons is driven by sensorimotor learning, and that, given suitable experience, mirror neurons will respond to any stimulus. This hypothesis was tested using fMRI adaptation to index populations of cells with mirror properties. After sensorimotor training, where geometric shapes were paired with hand actions, BOLD response was measured while human participants experienced runs of events in which shape observation alternated with action execution or observation. Adaptation from shapes to action execution, and critically, observation, occurred in ventral premotor cortex (PMv) and inferior parietal lobule (IPL). Adaptation from shapes to execution indicates that neuronal populations responding to the shapes had motor properties, while adaptation to observation demonstrates that these populations had mirror properties. These results indicate that sensorimotor training induced populations of cells with mirror properties in PMv and IPL to respond to the observation of arbitrary shapes. They suggest that the mirror system has not been shaped by evolution to respond in a mirror fashion to biological actions; instead, its development is mediated by stimulus-general processes of learning within a system adapted for visuomotor control.

Mirror theory applied to toroidal systems

International Nuclear Information System (INIS)

Cohen, R.H.

1987-01-01

Central features of a mirror plasma are strong departures from Maxwellian distribution functions, ambipolar potentials and densities which vary along a field line, and losses, and the mirror field itself. To examine these features, mirror theorists have developed analytical and numerical techniques to solve the Fokker-Planck equation, evaluate the potentials consistent with the resulting distribution functions, and assess the microstability of these distributions. Various combinations of mirror-plasma fetures are present and important in toroidal plasmas as well, particularly in the edge region and in plasmas with strong r.f. heating. In this paper we survey problems in toroidal plasmas where mirror theory and computational techniques are applicable, and discuss in more detail three specific examples: calculation of the toroidal generalization of the Spitzer-Haerm distribution function (from which trapped-particle effects on current drive can be calculated), evaluation of the nonuniform potential and density set up by pulsed electron-cyclotron heating, and calculation of steady-state distribution functions in the presence of strong r.f. heating and collisions. 37 refs., 3 figs

Mirror theory applied to toroidal systems

International Nuclear Information System (INIS)

Cohen, R.H.

1987-01-01

Central features of a mirror plasma are strong departures from Maxwellian distribution functions, ambipolar potentials and densities which vary along a field line, end losses, and the mirror field itself. To examine these features, mirror theorists have developed analytical and numerical techniques to solve the Fokker-Planck equation, evaluate the potentials consistent with the resulting distribution functions, and assess the microstability of these distributions. Various combinations of mirror-plasma features are present and important in toroidal plasmas as well, particularly in the edge region and in plasmas with strong rf heating. In this paper we survey problems in toroidal plasmas where mirror theory and computational techniques are applicable, and discuss in more detail three specific examples: calculation of the toroidal generalization of the Spitzer-Haerm distribution function (from which trapped-particle effects on current drive can be calculated), evaluation of the nonuniform potential and density set up by pulsed electron-cyclotron heating, and calculation of steady-state distribution functions in the presence of strong rf heating and collisions. 37 refs

CosmoQuest: Building a Community of Skilled Citizen Science Contributors

Science.gov (United States)

Gay, P.; Lehan, C.; Bracey, G.; Durrell, P.; Komatsu, T.; Yamani, A.; Francis, M. R.

2016-12-01

The CosmoQuest Virtual Research Facility invites the public to participate in NASA Science Mission Directorate related research that leads to publishable results and data catalogues. CosmoQuest projects range in difficulty from simple crater and transient marking tasks to more complicated mapping tasks. To successfully engage contributors in creating usable results, training and validation are required. This is accomplished through activities that are designed to mirror the experiences students would have in a university, and include mentoring by team scientists, feedback on contributor efforts, seminars to learn about new science, and even formal classes to provide needed background. Recruitment is accomplished using new and social media, and planetarium and Science on the Sphere™ trailers and shows, and community is built through online and real-world collaboration spaces and events. In this presentation, we detail CosmoQuest's four-pronged approach of media recruitment, science education, citizen science, and community collaboration. We also discuss how it is leveraged to create a skilled collaboration of citizen scientists. Training and data validation activities will be be emphasized, with examples of both what can go right and lessons learned from when things go wrong. We conclude with strategies on how to utilize best practices in user interface design to create virtual experiences that allow major citizen science efforts to be scalable to large audiences.

Vacuum-Flex Figuring of Primary Telescope Mirrors

Science.gov (United States)

Albin, E. F. M.

2004-12-01

In the current investigation, details on the construction and performance of a vacuum-flexed (i.e., figured) 51 cm (20-inch) mirror, with a fast f/4 focal ratio, are presented. A vacuum has the chief advantage of being able to pull with a uniform or isotropic stress across a large surface area, which will naturally form a parabolic surface. The essence of the idea is to grind and polish a spherical mirror and then warp or flex it into a near perfect paraboloid, thus avoiding tedious figuring altogether. To date, telescope makers around the globe have experimented with small flexed mirrors with considerable success. In these instances, mirrors have been flexed by exerting tension on a bolt or sponge-pad adhered to the back of the mirror. The prototype mirror consists of two 51 cm disks of plate glass -- each slumped to an f/4 focal ratio. The front-plate (19 mm in thickness) is separated from the back-plate (13 mm in thickness) back a flexible 9.5 mm air filled gasket. Although the rubber gasket makes a fairly good vacuum seal, silicon cement was placed about the outer edge in order to produce a perfectly tight seal. A vacuum of 8 kPa on the back of the mirror resulted in approximately 164 kilograms of negative pressure, which is required to flex the mirror into the required paraboloid. Ronchi test show a nice smooth paraboloid free from astigmatism while foucault zonal measurements display a figure better than 1/20 wave. Preliminary star testing show promising results as well. Vacuum-flexed mirrors may have benefits for both amateur and professional telescope makers alike. A US patent is pending on the aforementioned design.

The effectivenes of science domain-based science learning integrated with local potency

Science.gov (United States)

Kurniawati, Arifah Putri; Prasetyo, Zuhdan Kun; Wilujeng, Insih; Suryadarma, I. Gusti Putu

2017-08-01

This research aimed to determine the significant effect of science domain-based science learning integrated with local potency toward science process skills. The research method used was a quasi-experimental design with nonequivalent control group design. The population of this research was all students of class VII SMP Negeri 1 Muntilan. The sample of this research was selected through cluster random sampling, namely class VII B as an experiment class (24 students) and class VII C as a control class (24 students). This research used a test instrument that was adapted from Agus Dwianto's research. The aspect of science process skills in this research was observation, classification, interpretation and communication. The analysis of data used the one factor anova at 0,05 significance level and normalized gain score. The significance level result of science process skills with one factor anova is 0,000. It shows that the significance level < alpha (0,05). It means that there was significant effect of science domain-based science learning integrated with local potency toward science learning process skills. The results of analysis show that the normalized gain score are 0,29 (low category) in control class and 0,67 (medium category) in experiment class.

The Earth2Class Model for Professional Development to Implement the Next Generation Science Standards

Science.gov (United States)

Passow, M. J.; Assumpcao, C. M.; Baggio, F. D.; Hemming, S. R.; Goodwillie, A. M.; Brenner, C.

2014-12-01

Professional development for teachers involved in the implementation of the Next Generation Science Standards (NGSS) will require a multifaceted approach combining curriculum development, understanding the nature of science, applications of engineering and technology, integrating reading and writing, and other pedagogical components. The Earth2Class Workshops (E2C) at the Lamont-Doherty Earth Observatory of Columbia University (LDEO) provides one model for creating effective training to meet the NGSS challenges. E2C has provided more than 135 workshops since 1998 that have brought together LDEO research scientists with classroom teachers and students from the New York metropolitan area and elsewhere. Each session provides teachers with the chance to learn first-hand about the wide range of investigations conducted at LDEO. This approach aligns strongly with the NGSS goals: mastery of the disciplinary core ideas, science and engineering practices, understanding the nature of science, and cross-cutting relationships. During workshops, participating teachers interact with scientists to gain understanding of what stimulated research questions, how scientists put together all the components of investigations, and ways in which results are disseminated. Networking among teachers often leads to developing lesson plans based on the science, as well as support for professional growth not always possible within the school setting. Through the E2C website www.earth2class.org, teachers and students not able to attend the live workshops can access archival versions of the sessions. The website also provides a wide variety of educational resources. These have proved to be valuable on a national basis, as evidenced by an average of more than 300,000 hits per month from thousands of site visitors. Participating researchers have found E2C to be an effective approach to provide broader outreach of their results. During the next couple of years, the E2C program will expand to provide

Mirror neurons: From origin to function

OpenAIRE

Cook, R; Bird, G; Catmur, C; Press, C; Heyes, C

2014-01-01

This article argues that mirror neurons originate in sensorimotor associative learning and therefore a new approach is needed to investigate their functions. Mirror neurons were discovered about 20 years ago in the monkey brain, and there is now evidence that they are also present in the human brain. The intriguing feature of many mirror neurons is that they fire not only when the animal is performing an action, such as grasping an object using a power grip, but also when the animal passively...

Connection between adiabaticity and the mirror mode

International Nuclear Information System (INIS)

Cohen, R.H.

1976-01-01

The size of magnetic moment jumps of a particle in a long, thin equilibrium magnetic mirror field is shown to be related to the complex zeroes of the mirror mode parameter B + 4πdP/sub perpendicular//dB. A consequence is that adiabaticity places a lower limit on β than does the mirror mode

Imagining and Imaging the Social Brain: The Case of Mirror Neurons.

Science.gov (United States)

Lanzoni, Susan

In a contemporary setting in which all things "neuro" have great cultural sway, an analysis of the ways in which neuroscience is indebted to the methods and findings of the social sciences has received less attention. Indeed, in the new specialization of social neuroscience, neuroscientists now collaborate with contemporary psychologists and invoke historical psychological theories to help theorize empathy and social understanding. This article examines the overlap between psychological frameworks of social emotion and neuroscience in the case of mirror neurons, discovered in the 1990s. Some neuroscientists purport that mirror neurons underlie the social behaviours of imitation and empathy, and have found support for this view of theories of simulation and embodied cognition. They have also invoked pragmatic and phenomenological approaches to mind and behaviour dating back to the early 20 th century. Neuroscientists have thus imported, adapted, and interpreted psychological models to help define social understanding, empathy, and imitation in many imaging studies.

Doing, talking and writing science: A discourse analysis of the process of resemiotization in a middle school lab-based science class

Science.gov (United States)

Wright, Laura J.

This study examines students' sense making practices in a middle school science class from a discourse analytic perspective. Using Mediated Discourse Analysis (MDA) (Scollon 1998, 2001) and interactional sociolinguistics (Gumperz 1999, 2001, Schiffrin 1994), my research seeks to enrich findings from recent sociocultural studies of science classrooms that focus on doing, talking and writing science (Roth 2005, Kress, et al. 2002, Halliday & Martin 1993, Lemke 1990). Within a middle school science classroom, these fundamental activities form a nexus of practice (Scollon 1998, 2001) basic to science literacy (AAAS 1989) and reflective of the work of practicing scientists. Moreover, students' engagement in these practices provides insight into the cultural production and reproduction of science and scientist. I first examine how the students' curriculum text encourages these three scientific practices and then trace students' uptake; that is, how they subsequently do, talk, and write science throughout the course of the unit. I argue that learning science with this curriculum unit requires students to resemiotize (Iedema 2001, 2003) first hand experience so they can represent their knowledge cohesively and coherently in evaluable forms. Ultimately, students must transform language from the curriculum text and their teacher into action in their laboratory activities and action in their laboratory activities into language. In addition, I show how students are apprenticed to the conventionalized practices and voices (Bakhtin 1986) of science (i.e. the scientific register), and how their figures of personhood (Agha 2005) reflect the development of their scientific identities. Overall, I argue that the microanalytic methods I use illuminate how students draw upon curricular resources to become scientifically literate and develop scientific identities.

The eROSITA X-ray mirrors: technology and qualification aspects of the production of mandrels, shells and mirror modules

Science.gov (United States)

Arcangeli, L.; Borghi, G.; Bräuninger, H.; Citterio, O.; Ferrario, I.; Friedrich, P.; Grisoni, G.; Marioni, F.; Predehl, P.; Rossi, M.; Ritucci, A.; Valsecchi, G.; Vernani, D.

2017-11-01

The name "eROSITA" stands for extended Roentgen Survey with an Imaging Telescope Array. The general design of the eROSITA X-ray telescope is derived from that of ABRIXAS. A bundle of 7 mirror modules with short focal lengths make up a compact telescope which is ideal for survey observations. Similar designs had been proposed for the missions DUO and ROSITA but were not realized due to programmatic shortfall. Compared to those, however, the effective area in the soft X-ray band has now much increased by adding 27 additional outer mirror shells to the original 27 ones of each mirror module. The requirement on the on-axis resolution has also been confined, namely to 15 arc seconds HEW. For these reasons the prefix "extended" was added to the original name "ROSITA". The scientific motivation for this extension is founded in the ambitious goal to detect about 100,000 clusters of galaxies which trace the large scale structure of the Universe in space and time. The X-ray telescope of eROSITA will consist of 7 identical and co-aligned mirror modules, each with 54 nested Wolter-1 mirror shells. The mirror shells are glued onto a spider wheel which is screwed to the mirror interface structure making a rigid mechanical unit. The assembly of 7 modules forms a compact hexagonal configuration with 1300 mm diameter (see Fig. 1) and will be attached to the telescope structure which connects to the 7 separate CCD cameras in the focal planes. The co-alignment of the mirror module enables eROSITA to perform also pointed observations. The replication process described in chapter III allows the manufacturing in one single piece and at the same time of both the parabola and hyperbola parts of the Wolter 1 mirror.

Mirror dark matter and large scale structure

International Nuclear Information System (INIS)

Ignatiev, A.Yu.; Volkas, R.R.

2003-01-01

Mirror matter is a dark matter candidate. In this paper, we reexamine the linear regime of density perturbation growth in a universe containing mirror dark matter. Taking adiabatic scale-invariant perturbations as the input, we confirm that the resulting processed power spectrum is richer than for the more familiar cases of cold, warm and hot dark matter. The new features include a maximum at a certain scale λ max , collisional damping below a smaller characteristic scale λ S ' , with oscillatory perturbations between the two. These scales are functions of the fundamental parameters of the theory. In particular, they decrease for decreasing x, the ratio of the mirror plasma temperature to that of the ordinary. For x∼0.2, the scale λ max becomes galactic. Mirror dark matter therefore leads to bottom-up large scale structure formation, similar to conventional cold dark matter, for x(less-or-similar sign)0.2. Indeed, the smaller the value of x, the closer mirror dark matter resembles standard cold dark matter during the linear regime. The differences pertain to scales smaller than λ S ' in the linear regime, and generally in the nonlinear regime because mirror dark matter is chemically complex and to some extent dissipative. Lyman-α forest data and the early reionization epoch established by WMAP may hold the key to distinguishing mirror dark matter from WIMP-style cold dark matter

Mirror therapy: A potential intervention for pain management

Directory of Open Access Journals (Sweden)

Priscilla G. Wittkopf

Full Text Available Summary The consequences of chronic pain and associated disabilities to the patient and to the health care system are well known. Medication is often the first treatment of choice for chronic pain, although side effects and high costs restrict long-term use. Inexpensive, safe and easy to self-administer non-pharmacological therapies, such as mirror therapy, are recommended as adjuncts to pain treatment. The purpose of this review is to describe the principles of use of mirror therapy so it can be incorporated into a health care delivery. The physiological rationale of mirror therapy for the management of pain and the evidence of clinical efficacy based on recent systematic reviews are also discussed. Mirror therapy, whereby a mirror is placed in a position so that the patient can view a reflection of a body part, has been used to treat phantom limb pain, complex regional pain syndrome, neuropathy and low back pain. Research evidence suggests that a course of treatment (four weeks of mirror therapy may reduce chronic pain. Contraindications and side effects are few. The mechanism of action of mirror therapy remains uncertain, with reintegration of motor and sensory systems, restored body image and control over fear-avoidance likely to influence outcome. The evidence for clinical efficacy of mirror therapy is encouraging, but not yet definitive. Nevertheless, mirror therapy is inexpensive, safe and easy for the patient to self-administer.

FMRI evidence of 'mirror' responses to geometric shapes.

Directory of Open Access Journals (Sweden)

Clare Press

Full Text Available Mirror neurons may be a genetic adaptation for social interaction. Alternatively, the associative hypothesis proposes that the development of mirror neurons is driven by sensorimotor learning, and that, given suitable experience, mirror neurons will respond to any stimulus. This hypothesis was tested using fMRI adaptation to index populations of cells with mirror properties. After sensorimotor training, where geometric shapes were paired with hand actions, BOLD response was measured while human participants experienced runs of events in which shape observation alternated with action execution or observation. Adaptation from shapes to action execution, and critically, observation, occurred in ventral premotor cortex (PMv and inferior parietal lobule (IPL. Adaptation from shapes to execution indicates that neuronal populations responding to the shapes had motor properties, while adaptation to observation demonstrates that these populations had mirror properties. These results indicate that sensorimotor training induced populations of cells with mirror properties in PMv and IPL to respond to the observation of arbitrary shapes. They suggest that the mirror system has not been shaped by evolution to respond in a mirror fashion to biological actions; instead, its development is mediated by stimulus-general processes of learning within a system adapted for visuomotor control.

Coulomb energy differences in mirror nuclei

International Nuclear Information System (INIS)

Lenzi, Silvia M

2006-01-01

By comparing the excitation energies of analogue states in mirror nuclei, several nuclear structure properties can be studied as a function of the angular momentum up to high spin states. They can be described in the shell model framework by including electromagnetic and nuclear isospin-non-conserving interactions. Calculations for the mirror energy differences in nuclei of the f 7/2 shell are described and compared with recent experimental data. These studies are extended to mirror nuclei in the upper sd and fp shells

Carbon Fiber Mirror for a CubeSat Telescope

Science.gov (United States)

Kim, Young-Soo; Jang, Jeong Gyun; Kim, Jihun; Nam, Uk Won

2017-08-01

Telescope mirrors made by carbon fibers have been increasingly used especially for space applications, and they may replace the traditional glass mirrors. Glass mirrors are easy to fabricate, but needed to be carefully handled as they are brittle. Other materials have also been considered for telescope mirrors, such as metals, plastics, and liquids even. However glass and glass ceramics are still commonly and dominantly used.Carbon fiber has mainly been used for mechanical supports like truss structure and telescope tubes, as it is stiff and light-weight. It can also be a good material for telescope mirrors, as it has additional merits of non-brittle and very low thermal expansion. Therefore, carbon fiber mirror would be suitable for space telescopes which should endure the harsh vibration conditions during launch.A light-weight telescope made by carbon fiber has been designed for a small satellite which would have much less weight than conventional ones. In this poster, mirror materials are reviewed, and a design of carbon fiber telescope is presented and discussed.

Static Members of Classes in C#

Directory of Open Access Journals (Sweden)

Adrian LUPASC

2017-12-01

Full Text Available The C# language is object-oriented, which is why the declared member data must be part of a class. Thus, there is no possibility to declare certain variables that can be accessed from anywhere within the application, as it happens, for example, with global variables at the C language level. Making this work in C# is possible through static members of the class. Declaring a class implies defining some of its member data that later receive values when creating each object. A static member of the class can be interpreted as belonging only to the class, not to the objects subsequently created, which means that for the non-static data, there are as many children as there were objects created, while for the static ones there is only one copy, regardless of the number of created objects. In this regard, this paper presents the main aspects that characterize these abstract concepts of object oriented programming in general and C# language in particular, detailing how to develop an application that includes both static and non-static members. At the same time, particularities in the mirror for the two types of data, restrictions on use and potential limitations are presented.

'Adotta scienza e arte nella tua classe': The results of a successfully teaching project which combines science with art

International Nuclear Information System (INIS)

Giansanti, S.

2015-01-01

The project called 'Adotta scienza e arte nella tua classe' ('Adopt Science and Art in your class'), on the interconnection between science and art, has been addressed to the Italian secondary middle and high school involving more than 200 teachers and about 2200 students. The main purpose of this project is to make the young students aware of the strong link between science and art is a unique cultural and interdisciplinary occasion. To reach this goal, the Adotta project asked students to produce an artwork inspired by the interpretation of a quotation among a hundred commented quotes by physicists, mathematicians, scientist, writers, artists, accompanied by an original short sentence written by students themselves. More than 1000 artworks have been produced and collected in two galleries on Facebook. From their analysis emerges the students’ feeling about science, which is usually associated to human brain, based on mathematical laws and related to technological progress, but it is also a powerful tool that should be responsibly used. This project also valorizes teachers’ role in scientific education through activities that encourage students to recognize science in every aspect of their lives.

Long-Lived Glass Mirrors For Outer Space

Science.gov (United States)

Bouquet, Frank L.; Maag, Carl R.; Heggen, Philip M.

1988-01-01

Paper summarizes available knowledge about glass mirrors for use in outer space. Strengths and weaknesses of various types of first and second reflective surfaces identified. Second-surface glass mirrors used in outer space designed to different criteria more stringent for terrestrial mirrors. Protons, electrons, cosmic rays, meteorites, and orbiting space debris affect longevities of components. Contamination also factor in space.

Mirror position display equipment for the target chamber mirror mounts of the LASL HELIOS laser fusion facility

International Nuclear Information System (INIS)

Wells, F.D.; Remington, D.A.

1979-01-01

Equipment has been fabricated which records the absolute positions of sixteen mirror mounts used to direct and focus eight high-energy laser beams for research in laser induced fusion. Each mirror mount is driven by three stepping motors, controlled to produce the motions of Focus, Tilt, and Rotate relative to the target. Stepping of the motors is sensed by incremental optical encoders coupled to the motor drive shafts. Outputs from the encoder tracks are multiplexed to a microprocessor which transmits motor step information via a fiber optical data link to a Mirror Position Display chassis. This unit accumulates the steps, stores the motor positions, displays mirror position data to the operator, and provides the equipment control functions. Standby battery power is included to retain the motor step data in the event of power failure

Mirror neuron system: basic findings and clinical applications.

Science.gov (United States)

Iacoboni, Marco; Mazziotta, John C

2007-09-01

In primates, ventral premotor and rostral inferior parietal neurons fire during the execution of hand and mouth actions. Some cells (called mirror neurons) also fire when hand and mouth actions are just observed. Mirror neurons provide a simple neural mechanism for understanding the actions of others. In humans, posterior inferior frontal and rostral inferior parietal areas have mirror properties. These human areas are relevant to imitative learning and social behavior. Indeed, the socially isolating condition of autism is associated with a deficit in mirror neuron areas. Strategies inspired by mirror neuron research recently have been used in the treatment of autism and in motor rehabilitation after stroke.

James Webb Space Telescope Optical Simulation Testbed: Segmented Mirror Phase Retrieval Testing

Science.gov (United States)

Laginja, Iva; Egron, Sylvain; Brady, Greg; Soummer, Remi; Lajoie, Charles-Philippe; Bonnefois, Aurélie; Long, Joseph; Michau, Vincent; Choquet, Elodie; Ferrari, Marc; Leboulleux, Lucie; Mazoyer, Johan; N’Diaye, Mamadou; Perrin, Marshall; Petrone, Peter; Pueyo, Laurent; Sivaramakrishnan, Anand

2018-01-01

The James Webb Space Telescope (JWST) Optical Simulation Testbed (JOST) is a hardware simulator designed to produce JWST-like images. A model of the JWST three mirror anastigmat is realized with three lenses in form of a Cooke Triplet, which provides JWST-like optical quality over a field equivalent to a NIRCam module, and an Iris AO segmented mirror with hexagonal elements is standing in for the JWST segmented primary. This setup successfully produces images extremely similar to NIRCam images from cryotesting in terms of the PSF morphology and sampling relative to the diffraction limit.The testbed is used for staff training of the wavefront sensing and control (WFS&C) team and for independent analysis of WFS&C scenarios of the JWST. Algorithms like geometric phase retrieval (GPR) that may be used in flight and potential upgrades to JWST WFS&C will be explored. We report on the current status of the testbed after alignment, implementation of the segmented mirror, and testing of phase retrieval techniques.This optical bench complements other work at the Makidon laboratory at the Space Telescope Science Institute, including the investigation of coronagraphy for segmented aperture telescopes. Beyond JWST we intend to use JOST for WFS&C studies for future large segmented space telescopes such as LUVOIR.

X-ray beam-shaping via deformable mirrors: Analytical computation of the required mirror profile

International Nuclear Information System (INIS)

Spiga, Daniele; Raimondi, Lorenzo; Svetina, Cristian; Zangrando, Marco

2013-01-01

X-ray mirrors with high focusing performances are in use in both mirror modules for X-ray telescopes and in synchrotron and FEL (Free Electron Laser) beamlines. A degradation of the focus sharpness arises in general from geometrical deformations and surface roughness, the former usually described by geometrical optics and the latter by physical optics. In general, technological developments are aimed at a very tight focusing, which requires the mirror profile to comply with the nominal shape as much as possible and to keep the roughness at a negligible level. However, a deliberate deformation of the mirror can be made to endow the focus with a desired size and distribution, via piezo actuators as done at the EIS-TIMEX beamline of FERMI@Elettra. The resulting profile can be characterized with a Long Trace Profilometer and correlated with the expected optical quality via a wavefront propagation code. However, if the roughness contribution can be neglected, the computation can be performed via a ray-tracing routine, and, under opportune assumptions, the focal spot profile (the Point Spread Function, PSF) can even be predicted analytically. The advantage of this approach is that the analytical relation can be reversed; i.e., from the desired PSF the required mirror profile can be computed easily, thereby avoiding the use of complex and time-consuming numerical codes. The method can also be suited in the case of spatially inhomogeneous beam intensities, as commonly experienced at synchrotrons and FELs. In this work we expose the analytical method and the application to the beam shaping problem

Virtual Mirror gaming in libraries

NARCIS (Netherlands)

Speelman, M.; Kröse, B.; Nijholt, A.; Poppe, R.

2008-01-01

This paper presents a study on a natural interface game in the context of a library. We developed a camera-based Virtual Mirror (VM) game, in which the player can see himself on the screen as if he looks at a mirror image. We present an overview of the different aspects of VM games and technologies

Characterization of a piezo bendable X-ray mirror.

Science.gov (United States)

Vannoni, Maurizio; Freijo Martín, Idoia; Siewert, Frank; Signorato, Riccardo; Yang, Fan; Sinn, Harald

2016-01-01

A full-scale piezo bendable mirror built as a prototype for an offset mirror at the European XFEL is characterized. The piezo ceramic elements are glued onto the mirror substrate, side-face on with respect to the reflecting surface. Using a nanometre optical component measuring machine and a large-aperture Fizeau interferometer, the mirror profile and influence functions were characterized, and further analysis was made to investigate the junction effect, hysteresis, twisting and reproducibility.

Electrostatic ion confinement in a magnetic mirror field

International Nuclear Information System (INIS)

Nishida, Y.; Kawamata, S.; Ishii, K.

1976-08-01

The electrostatic ion stoppering at the mirror point is demonstrated experimentally in a magnetic mirror field. The ion losses from the mirror throat are decreased to about 15% of the initial losses in a rather high plasma density (10 10 0 13 cm -3 ). It is discussed as a confinement mechanism of ions that particles are reflected back adiabatically at the throat of the magnetic mirror field supplemented by DC electric field. (auth.)

"Mirror agnosia" in a patient with right occipitotemporal infarct

Directory of Open Access Journals (Sweden)

Menon Bijoy

2006-01-01

Full Text Available We report the clinical profile and investigation of K, a patient suffering from agnosia for the concept of "mirrors". Normal people rarely confuse a mirror image for the real image. Our patient ′K′ has intact attention, memory and language with a left visual neglect with left hemianopia. When shown an object on his left with a mirror kept sagitally on his right, K grabs for the reflection and even gropes behind the mirror for it. Yet, when shown the mirror alone, he is able to tell that it is a mirror. Thus the concept of a ′mirror′ is lost in the experimental paradigm. An explanation for mirror ′agnosia′ is provided and recent controversies in the analysis of visuospatial functions in humans is highlighted.

From Proposal Writing to Data Collection to Presentation: Physical Oceanography Laboratory Class Students Explore the Fundamentals of Science

Science.gov (United States)

Buijsman, M. C.; Church, I.; Haydel, J.; Martin, K. M.; Shiller, A. M.; Wallace, D. J.; Blancher, J.; Foltz, A.; Griffis, A. M.; Kosciuch, T. J.; Kincketootle, A.; Pierce, E.; Young, V. A.

2016-02-01

To better prepare first-year Department of Marine Science MSc students of the University of Southern Mississippi for their science careers, we plan to execute a semester-long Physical Oceanography laboratory class that exposes the enrolled students to all aspects of interdisciplinary research: writing a proposal, planning a cruise, collecting and analyzing data, and presenting their results. Although some of these aspects may be taught in any such class, the incorporation of all these aspects makes this class unique.The fieldwork will be conducted by boat in the Rigolets in Louisiana, a 13-km long tidal strait up to 1 km wide connecting the Mississippi Sound with Lake Pontchartrain. The students have the opportunity to collect ADCP, CTD, multibeam sonar, sediment and water samples.A second novel characteristic of this class is that the instructor partnered with the Lake Pontchartrain Basin Foundation, a not for profit environmental advocacy group. The foundation will give an hour-long seminar on the natural history of the study area and its environmental problems. This information provides context for the students' research proposals and allows them to formulate research questions and hypotheses that connect their research objectives to societally relevant issues, such as coastal erosion, salt water intrusion, and water quality. The proposal writing and cruise planning is done in the first month of the 3.5-month long semester. In the second month two surveys are conducted. The remainder of the semester is spent on analysis and reporting. Whenever possible we teach Matlab for the students to use in their data analysis. In this presentation, we will report on the successes and difficulties associated with teaching such a multi-faceted class.

Enhancing students' science literacy using solar cell learning multimedia containing science and nano technology

Science.gov (United States)

Eliyawati, Sunarya, Yayan; Mudzakir, Ahmad

2017-05-01

This research attempts to enhance students' science literacy in the aspects of students' science content, application context, process, and students' attitude using solar cell learning multimedia containing science and nano technology. The quasi-experimental method with pre-post test design was used to achieve these objectives. Seventy-two students of class XII at a high school were employed as research's subject. Thirty-six students were in control class and another thirty-six were in experiment class. Variance test (t-test) was performed on the average level of 95% to identify the differences of students' science literacy in both classes. As the result, there were significant different of learning outcomes between experiment class and control class. Almost half of students (41.67%) in experiment class are categorized as high. Therefore, the learning using solar cell learning multimedia can improve students' science literacy, especially in the students' science content, application context, and process aspects with n-gain(%) 59.19 (medium), 63.04 (medium), and 52.98 (medium). This study can be used to develop learning multimedia in other science context.

Mirror Fusion Test Facility magnet system

International Nuclear Information System (INIS)

VanSant, J.H.; Kozman, T.A.; Bulmer, R.H.; Ng, D.S.

1981-01-01

In 1979, R.H. Bulmer of Lawrence Livermore National Laboratory (LLNL) discussed a proposed tandem-mirror magnet system for the Mirror Fusion Test Facility (MFTF) at the 8th symposium on Engineering Problems in Fusion Research. Since then, Congress has voted funds for expanding LLNL's MFTF to a tandem-mirror facility (designated MFTF-B). The new facility, scheduled for completion by 1985, will seek to achieve two goals: (1) Energy break-even capability (Q or the ratio of fusion energy to plasma heating energy = 1) of mirror fusion, (2) Engineering feasibility of reactor-scale machines. Briefly stated, 22 superconducting magnets contained in a 11-m-diam by 65-m-long vacuum vessel will confine a fusion plasma fueled by 80 axial streaming-plasma guns and over 40 radial neutral beams. We have already completed a preliminary design of this magnet system

Reducing the Surface Performance Requirements of a Primary Mirror by Adding a Deformable Mirror in its Optical Path

Science.gov (United States)

2015-12-01

data. Of note, the interferometer compensates for the double -pass induced by single reflections off a surface by diving all measurements by 2. However...the interferometer. Since the laser reflects off the CFRP mirror only once, the CFRP wavefront measurements did not require additional double -pass...conducted with a flat mirror in the optical path. Figure 13 presents the measured wavefront error of the CFRP mirror with piston , tip and tip removed and

Present status of mirror stability theory

International Nuclear Information System (INIS)

Baldwin, D.E.; Berk, H.L.; Byers, J.A.

1976-01-01

A status report of microinstability as it applies to 2XIIB and MX theory for mirror machines is presented. It is shown that quasilinear computations reproduce many of the parameters observed in the 2XIIB experiment. In regard to large mirror machines, there are presented detailed calculations of the linear theory of the drift cyclotron loss-cone mode, with inhomogeneous geometry and nonlinear diffusive effects. Further, the stability of a mirror machine to the Alfven ion-cyclotron instability is assessed, and the Baldwin-Callen diffusion is estimated for a spatially varying plasma

Mirroring Facial Expressions and Emotions in Dyadic Conversations

DEFF Research Database (Denmark)

Navarretta, Costanza

2016-01-01

This paper presents an investigation of mirroring facial expressions and the emotions which they convey in dyadic naturally occurring first encounters. Mirroring facial expressions are a common phenomenon in face-to-face interactions, and they are due to the mirror neuron system which has been...... and overlapping facial expressions are very frequent. In this study, we want to determine whether the overlapping facial expressions are mirrored or are otherwise correlated in the encounters, and to what extent mirroring facial expressions convey the same emotion. The results of our study show that the majority...... of smiles and laughs, and one fifth of the occurrences of raised eyebrows are mirrored in the data. Moreover some facial traits in co-occurring expressions co-occur more often than it would be expected by chance. Finally, amusement, and to a lesser extent friendliness, are often emotions shared by both...

Kodak Mirror Assembly Tested at Marshall Space Flight Center

Science.gov (United States)

2003-01-01

This photo (a frontal view) is of one of many segments of the Eastman-Kodak mirror assembly being tested for the James Webb Space Telescope (JWST) project at the X-Ray Calibration Facility at Marshall Space Flight Center (MSFC). MSFC is supporting Goddard Space Flight Center (GSFC) in developing the JWST by taking numerous measurements to predict its future performance. The tests are conducted in a vacuum chamber cooled to approximate the super cold temperatures found in space. During its 27 years of operation, the facility has performed testing in support of a wide array of projects, including the Hubble Space Telescope (HST), Solar A, Chandra technology development, Chandra High Resolution Mirror Assembly and science instruments, Constellation X-Ray Mission, and Solar X-Ray Imager, currently operating on a Geostationary Operational Environment Satellite. The JWST is NASA's next generation space telescope, a successor to the Hubble Space Telescope, named in honor of NASA's second administrator, James E. Webb. It is scheduled for launch in 2010 aboard an expendable launch vehicle. It will take about 3 months for the spacecraft to reach its destination, an orbit of 940,000 miles in space.

Ten Decades of the Science Textbook: A Revealing Mirror of Science Education Past and Present.

Science.gov (United States)

Lynch, Paddy P.; Strube, Paul D.

1985-01-01

Indicates that trends in science education can be examined by examining science textbook content. Suggests that a historical overview is important and pertinent to contemporary thinking and contemporary problems in science education. (Author/JN)

X-ray total reflection mirrors for coherent illumination

CERN Document Server

Ishikawa, T; Yabashi, M; Souvorov, A; Yamauchi, K; Yamamura, K; Mimura, H; Saito, A; Mori, Y

2002-01-01

X-ray mirrors for coherent illumination demand much higher surface quality than is achievable with the conventional polishing techniques. Plasma chemical vaporization machining (CVM) and elastic emission machining (EEM) have been applied for x-ray mirror manufacturing. Figure error of a flat silicon single crystal mirrors made with CVM+EEM process was reduced to 2.0 nm peak-to-valley and 0.2 nm RMS. The machining process was also applied to make elliptical mirrors. One-dimensional focusing with a single elliptical mirror showed diffraction-limited properties with the focal width of 200 nm. Two-dimensional focusing with Kirkpatric-Baez configuration gave a focal spot size of 200 nm x 200 nm. (author)

UHV mirror mounts for photophysics beamline at Indus-I

International Nuclear Information System (INIS)

Meenakshi Raja Rao, P.; Bhattacharya, S.S.; Das, N.C.; Rajasekhar, B.N.; Roy, A.P.

1995-01-01

Photophysics beamline makes use of a combination of two toroidal mirrors and one meter Seya-Namioka Monochromator in its fore optics. The fore optics monochromatises and steers the synchrotron radiation source (SRS) beam from its tangent point to the sample situated at a distance of about five meters. Slit widths of the monochromator are of the order of 100μ and the sample size is one mm 2 . Hence it is essential to impart precision rotational and translational movements of the same order of magnitude to the mirrors with the use of appropriate mirror mounts. Since Indus-1 operates at a pressure -9 mbar, the mirror mounts should be UHV compatible and the movements should be actuated under UHV. The mirrors along with the mirror mounts are enclosed in UHV chambers. The mirror chambers have been fabricated at Centre for Advanced Technology (CAT) workshops and tested up to a pressure of 10 -9 mbar. The mirror mounts are designed, fabricated and leak checked (He leak rate -10 std cc/s) The precision movements are achieved with the help of bellow sealed shaft mechanism and adjustable screws provided with the kinematic mount of the mirror frame. The performance of the mirror mount was tested at atmospheric pressure by using a laser beam and found to be good. The minimum displacement of the laser beam at slit and sample positions is ∼ 70μ which is quite adequate for optical alignment. The performance of the mirror mount under UHV conditions is being evaluated. (author). 4 refs., 3 figs

Anomalous transport in mirror systems

International Nuclear Information System (INIS)

Post, R.F.

1979-01-01

As now being explored for fusion applications confinement systems based on the mirror principle embody two kinds of plasma regimes. These two regimes are: (a) high-beta plasmas, stabilized against MHD and other low frequency plasma instabilities by magnetic-well fields, but characterized by non-Maxwellian ion distributions; (b) near-Maxwellian plasmas, confined electrostatically (as in the tandem mirror) or in a field-reversed region within the mirror cell. Common to both situations are the questions of anomalous transport owing to high frequency instabilities in the non-maxwellian portions of the plasmas. This report will summarize the status of theory and of experimental data bearing on these questions, with particular reference to the high temperature regimes of interest for fusion power

Dynamic characteristics of mirrors' kinematic mount

International Nuclear Information System (INIS)

Wu Wenkai; Du Qiang; Li Jingze; Chen Gang; Chen Xiaojuan; Xu Yuanli

2002-01-01

Applying exact constrain design principles, kinematic mount for precision positioning large aperture mirrors is designed; theoretical method is introduced to analyze its dynamic characteristics and the result of the experiment for mirrors, stability; accordingly, the methods to improve design are put forward

Cosmological Constraints on Mirror Matter Parameters

International Nuclear Information System (INIS)

Wallemacq, Quentin; Ciarcelluti, Paolo

2014-01-01

Up-to-date estimates of the cosmological parameters are presented as a result of numerical simulations of cosmic microwave background and large scale structure, considering a flat Universe in which the dark matter is made entirely or partly of mirror matter, and the primordial perturbations are scalar adiabatic and in linear regime. A statistical analysis using the Markov Chain Monte Carlo method allows to obtain constraints of the cosmological parameters. As a result, we show that a Universe with pure mirror dark matter is statistically equivalent to the case of an admixture with cold dark matter. The upper limits for the ratio of the temperatures of ordinary and mirror sectors are around 0.3 for both the cosmological models, which show the presence of a dominant fraction of mirror matter, 0.06≲Ω_m_i_r_r_o_rh"2≲0.12.

AMTD: update of engineering specifications derived from science requirements for future UVOIR space telescopes

Science.gov (United States)

Stahl, H. Philip; Postman, Marc; Mosier, Gary; Smith, W. Scott; Blaurock, Carl; Ha, Kong; Stark, Christopher C.

2014-08-01

The Advance Mirror Technology Development (AMTD) project is in Phase 2 of a multiyear effort, initiated in FY12, to mature by at least a half TRL step six critical technologies required to enable 4 meter or larger UVOIR space telescope primary mirror assemblies for both general astrophysics and ultra-high contrast observations of exoplanets. AMTD uses a science-driven systems engineering approach. We mature technologies required to enable the highest priority science AND provide a high-performance low-cost low-risk system. To give the science community options, we are pursuing multiple technology paths. A key task is deriving engineering specifications for advanced normal-incidence monolithic and segmented mirror systems needed to enable both general astrophysics and ultra-high contrast observations of exoplanets missions as a function of potential launch vehicles and their mass and volume constraints. A key finding of this effort is that the science requires an 8 meter or larger aperture telescope.

Error reduction techniques for measuring long synchrotron mirrors

International Nuclear Information System (INIS)

Irick, S.

1998-07-01

Many instruments and techniques are used for measuring long mirror surfaces. A Fizeau interferometer may be used to measure mirrors much longer than the interferometer aperture size by using grazing incidence at the mirror surface and analyzing the light reflected from a flat end mirror. Advantages of this technique are data acquisition speed and use of a common instrument. Disadvantages are reduced sampling interval, uncertainty of tangential position, and sagittal/tangential aspect ratio other than unity. Also, deep aspheric surfaces cannot be measured on a Fizeau interferometer without a specially made fringe nulling holographic plate. Other scanning instruments have been developed for measuring height, slope, or curvature profiles of the surface, but lack accuracy for very long scans required for X-ray synchrotron mirrors. The Long Trace Profiler (LTP) was developed specifically for long x-ray mirror measurement, and still outperforms other instruments, especially for aspheres. Thus, this paper focuses on error reduction techniques for the LTP

Identifying Students' Expectancy-Value Beliefs: A Latent Class Analysis Approach to Analyzing Middle School Students' Science Self-Perceptions

Science.gov (United States)

Phelan, Julia; Ing, Marsha; Nylund-Gibson, Karen; Brown, Richard S.

2017-01-01

This study extends current research by organizing information about students' expectancy-value achievement motivation, in a way that helps parents and teachers identify specific entry points to encourage and support students' science aspirations. This study uses latent class analysis to describe underlying differences in ability beliefs, task…

Modern science in Portugal: the ‘class of the sphere’ in the college of Saint Anthony

Directory of Open Access Journals (Sweden)

Natália Cristina de Oliveira

2017-05-01

Full Text Available With the arrival of the Society of Jesus to Portugal in 1540, Jesuit schools were created by the Crown. The College of St. Anthony, in Lisbon, was the first Jesuit educational institution, created in 1553. We propose a discussion of the main objectives, characteristics and difficulties of the Jesuit religious order in the Portuguese territory, as well as a presentation of one of the most important classes of this College: the ‘Class of the Sphere’. The priests considered fundamental to teach issues related to mathematics and astronomy, because, through these disciplines, they addressed the theory and practice of items and concepts, such as the telescope, logarithms, equations, geometry and others. The curriculum of this college included, in addition to science and mathematics, subjects such as: Latin, Grammar, Humanities, Rhetoric, and Introduction to Moral Theology, Dogmatic Theology and Philosophy, considered only to teaching in the Portuguese context. Studying the College of St. Anthony helps us to understand how these innovations were considered in teaching, in the Jesuit case, in the temporal context of Portugal in the 16th century. We understand that the College, mainly by innovations, was essential to the development of science.

Rubbing Elbows and Blowing Smoke: Gender, Class, and Science in the Nineteenth-Century Patent Office.

Science.gov (United States)

Swanson, Kara W

2017-03-01

The United States Patent Office of the 1850s offers a rare opportunity to analyze the early gendering of science. In its crowded rooms, would-be scientists shared a workplace with women earning equal pay for equal work. Scientific men worked as patent examiners, claiming this new occupation as scientific in opposition to those seeking to separate science and technology. At the same time, in an unprecedented and ultimately unsuccessful experiment, female clerks were hired to work alongside male clerks. This article examines the controversies surrounding these workers through the lens of manners and deportment. In the unique context of a workplace combining scientific men and working ladies, office behavior revealed the deep assumption that the emerging American scientist was male and middle class.

Mirror system based therapy for autism spectrum disorders

Institute of Scientific and Technical Information of China (English)

Wei CHEN; Jing ZHANG; Jun DING

2008-01-01

This paper reviews the present theories and empirical research of autisms' cognitive research and mir-ror systems and introduces a new hypothesis about the causes of autism spectrum disorders (ASD): autistic mir-ror neuron dysfunction hypothesis. ASD subjects show obvious lack of the activation of the mirror system during the task of observation or emotional cognition. It is sig-nificant to investigate the mirror system for revealing the causes of autism and it is also helpful for developing new ways to diagnose or treat this disorder.

Parametric studies of tandem mirror reactors

International Nuclear Information System (INIS)

Carlson, G.A.; Boghosian, B.M.; Fink, J.H.; Myall, J.O.; Neef, W.S. Jr.

1979-01-01

This report, along with its companion, An Improved Tandem Mirror Reactor, discusses the recent progress and present status of our tandem mirror reactor studies. This report presents the detailed results of parametric studies up to, but not including, the very new ideas involving thermal barriers

Matrix model as a mirror of Chern-Simons theory

International Nuclear Information System (INIS)

Aganagic, Mina; Klemm, Albrecht; Marino, Marcos; Vafa, Cumrun

2004-01-01

Using mirror symmetry, we show that Chern-Simons theory on certain manifolds such as lens spaces reduces to a novel class of Hermitian matrix models, where the measure is that of unitary matrix models. We show that this agrees with the more conventional canonical quantization of Chern-Simons theory. Moreover, large N dualities in this context lead to computation of all genus A-model topological amplitudes on toric Calabi-Yau manifolds in terms of matrix integrals. In the context of type IIA superstring compactifications on these Calabi-Yau manifolds with wrapped D6 branes (which are dual to M-theory on G2 manifolds) this leads to engineering and solving F-terms for N=1 supersymmetric gauge theories with superpotentials involving certain multi-trace operators. (author)

MARS: Mirror Advanced Reactor Study

International Nuclear Information System (INIS)

Logan, B.G.

1984-01-01

A recently completed two-year study of a commercial tandem mirror reactor design [Mirror Advanced Reactor Study (MARS)] is briefly reviewed. The end plugs are designed for trapped particle stability, MHD ballooning, balanced geodesic curvature, and small radial electric fields in the central cell. New technologies such as lithium-lead blankets, 24T hybrid coils, gridless direct converters and plasma halo vacuum pumps are highlighted

X-ray microscope with a Wolter mirror

International Nuclear Information System (INIS)

Watanabe, Norio; Aoki, Sadao

2003-01-01

A Wolter mirror as an objective of an X-ray microscope is described. In comparison with other optical elements, a Wolter mirror has several advantages, such as a large numerical aperture and no chromatic aberration. Recent developments of fabrication process enabled us to make a Wolter mirror objective for X-rays. The fabrication process and the applications to a soft X-ray microscope and an X-ray fluorescence microscope are described. (author)

Age-specific effects of mirror-muscle activity on cross-limb adaptations under mirror and non-mirror visual feedback conditions.

Directory of Open Access Journals (Sweden)

Paola eReissig

2015-12-01

Full Text Available Cross-limb transfer (CLT describes the observation of bilateral performance gains due to unilateral motor practice. Previous research has suggested that CLT may be reduced, or absent, in older adults, possibly due to age-related structural and functional brain changes. Based on research showing increases in CLT due to the provision of mirror visual feedback (MVF during task execution in young adults, our study aimed to investigate whether MVF can facilitate CLT in older adults, who are known to be more reliant on visual feedback for accurate motor performance. Participants (N = 53 engaged in a short-term training regime (300 movements involving a ballistic finger task using their dominant hand, while being provided with either visual feedback of their active limb, or a mirror reflection of their active limb (superimposed over the quiescent limb. Bilateral performance was examined before, during and following the training. Furthermore, we measured corticospinal excitability (using TMS at these time points, and assessed muscle activity bilaterally during the task via EMG; these parameters were used to investigate the mechanisms mediating and predicting CLT. Training resulted in significant bilateral performance gains that did not differ as a result of age or visual feedback (all ps > 0.1. Training also elicited bilateral increases in corticospinal excitability (p < 0.05. For younger adults, CLT was significantly predicted by performance gains in the trained hand (β = 0.47, whereas for older adults it was significantly predicted by mirror activity in the untrained hand during training (β = 0.60. The present study suggests that older adults are capable of exhibiting CLT to a similar degree to younger adults. The prominent role of mirror activity in the untrained hand for CLT in older adults indicates that bilateral cortical activity during unilateral motor tasks is a compensatory mechanism. In this particular task, MVF did not facilitate the

Recovery of Proprioception in the Upper Extremity by Robotic Mirror Therapy: a Clinical Pilot Study for Proof of Concept.

Science.gov (United States)

Nam, Hyung Seok; Koh, Sukgyu; Beom, Jaewon; Kim, Yoon Jae; Park, Jang Woo; Koh, Eun Sil; Chung, Sun Gun; Kim, Sungwan

2017-10-01

A novel robotic mirror therapy system was recently developed to provide proprioceptive stimulus to the hemiplegic arm during a mirror therapy. Validation of the robotic mirror therapy system was performed to confirm its synchronicity prior to the clinical study. The mean error angle range between the intact arm and the robot was 1.97 to 4.59 degrees. A 56-year-old male who had right middle cerebral artery infarction 11 months ago received the robotic mirror therapy for ten 30-minute sessions during 2 weeks. Clinical evaluation and functional magnetic resonance imaging (fMRI) studies were performed before and after the intervention. At the follow-up evaluation, the thumb finding test score improved from 2 to 1 for eye level and from 3 to 1 for overhead level. The Albert's test score on the left side improved from 6 to 11. Improvements were sustained at 2-month follow-up. The fMRI during the passive motion revealed a considerable increase in brain activity at the lower part of the right superior parietal lobule, suggesting the possibility of proprioception enhancement. The robotic mirror therapy system may serve as a useful treatment method for patients with supratentorial stroke to facilitate recovery of proprioceptive deficit and hemineglect. © 2017 The Korean Academy of Medical Sciences.

T-branes through 3d mirror symmetry

Energy Technology Data Exchange (ETDEWEB)

Collinucci, Andrés; Giacomelli, Simone [Physique Théorique et Mathématique and International Solvay Institutes,Université Libre de Bruxelles,C.P. 231, 1050 Bruxelles (Belgium); Savelli, Raffaele [Institut de Physique Théorique, CEA Saclay,Orme de Merisiers, F-91191 Gif-sur-Yvette (France); Valandro, Roberto [Dipartimento di Fisica, Università di Trieste,Strada Costiera 11, 34151 Trieste (Italy); INFN, Sezione di Trieste,Via Valerio 2, 34127 Trieste (Italy); Abdus Salam International Centre for Theoretical Physics,Strada Costiera 11, 34151 Trieste (Italy)

2016-07-19

T-branes are exotic bound states of D-branes, characterized by mutually non-commuting vacuum expectation values for the worldvolume scalars. The M/F-theory geometry lifting D6/D7-brane configurations is blind to the T-brane data. In this paper, we make this data manifest, by probing the geometry with an M2-brane. We find that the effect of a T-brane is to deform the membrane worldvolume superpotential with monopole operators, which partially break the three-dimensional flavor symmetry, and reduce supersymmetry from N=4 to N=2. Our main tool is 3d mirror symmetry. Through this language, a very concrete framework is developed for understanding T-branes in M-theory. This leads us to uncover a new class of N=2 quiver gauge theories, whose Higgs branches mimic those of membranes at ADE singularities, but whose Coulomb branches differ from their N=4 counterparts.

Using News Media Databases (LexisNexis) To Identify Relevant Topics For Introductory Earth Science Classes

Science.gov (United States)

Cervato, C.; Jach, J. Y.; Ridky, R.

2003-12-01

Introductory Earth science courses are undergoing pedagogical changes in universities across the country and are focusing more than ever on the non-science majors. Increasing enrollment of non-science majors in these introductory Earth science courses demands a new look at what is being taught and how the content can be objectively chosen. Assessing the content and effectiveness of these courses requires a quantitative investigation of introductory Earth science topics and their relevance to current issues and concerns. Relevance of Earth science topics can be linked to improved students' attitude toward science and a deeper understanding of concepts. We have used the Internet based national news search-engine LexisNexis Academic Universe (http://www.lexisnexis.org/) to select the occurrence of Earth science terms over the last 12 months, five and ten years both regionally and nationally. This database of term occurrences is being used to examine how Earth sciences have evolved in the news through the last 10 years and is also compared with textbook contents and course syllabi from randomly selected introductory earth science courses across the nation. These data constitute the quantitative foundation for this study and are being used to evaluate the relevance of introductory earth science course content. The relevance of introductory course content and current real-world issues to student attitudes is a crucial factor when considering changes in course curricula and pedagogy. We have examined students' conception of the nature of science and attitudes towards science and learning science using a Likert-scale assessment instrument in the fall 2002 Geology 100 classes at Iowa State University. A pre-test and post-test were administered to see if the students' attitudes changed during the semester using as reference a control group comprised of geoscience undergraduate and graduate students, and faculty. The results of the attitude survey have been analyzed in terms

Dynamic range of low-voltage cascode current mirrors

DEFF Research Database (Denmark)

Bruun, Erik; Shah, Peter Jivan

1995-01-01

Low-voltage cascode current mirrors are reviewed with respect to the design limitations imposed if all transistors in the mirror are required to operate in the saturation region. It is found that both a lower limit and an upper limit exist for the cascode transistor bias voltage. Further, the use....... The proposed configuration has the advantage of simplicity combined with a complete elimination of the need for fixed bias voltages or bias currents in the current mirror. A disadvantage is that it requires a higher input voltage to the current mirror...

Mirror Advanced Reactor Study (MARS) final report summary

International Nuclear Information System (INIS)

Henning, C.D.; Logan, B.G.; Carlson, G.A.

1983-01-01

The Mirror Advanced Reactor Study (MARS) has resulted in an overview of a first-generation tandem mirror reactor. The central cell fusion plasma is self-sustained by alpha heating (ignition), while electron-cyclotron resonance heating and negative ion beams maintain the electrostatic confining potentials in the end plugs. Plug injection power is reduced by the use of high-field choke coils and thermal barriers, concepts to be tested in the Tandem Mirror Experiment-Upgrade (TMX-U) and Mirror Fusion Test Facility (MFTF-B) at Lawrence Livermore National Laboratory

Brane brick models in the mirror

Energy Technology Data Exchange (ETDEWEB)

Franco, Sebastián [Physics Department, The City College of the CUNY,160 Convent Avenue, New York, NY 10031 (United States); The Graduate School and University Center, The City University of New York,365 Fifth Avenue, New York NY 10016 (United States); Lee, Sangmin [Center for Theoretical Physics, Seoul National University,Seoul 08826 (Korea, Republic of); Department of Physics and Astronomy, Seoul National University,Seoul 08826 (Korea, Republic of); College of Liberal Studies, Seoul National University,Seoul 08826 (Korea, Republic of); Seong, Rak-Kyeong [School of Physics, Korea Institute for Advanced Study,Seoul 02455 (Korea, Republic of); Vafa, Cumrun [Jefferson Physical Laboratory, Harvard University,Cambridge, MA 02138 (United States)

2017-02-21

Brane brick models are Type IIA brane configurations that encode the 2dN=(0,2) gauge theories on the worldvolume of D1-branes probing toric Calabi-Yau 4-folds. We use mirror symmetry to improve our understanding of this correspondence and to provide a systematic approach for constructing brane brick models starting from geometry. The mirror configuration consists of D5-branes wrapping 4-spheres and the gauge theory is determined by how they intersect. We also explain how 2d(0,2) triality is realized in terms of geometric transitions in the mirror geometry. Mirror symmetry leads to a geometric unification of dualities in different dimensions, where the order of duality is n−1 for a Calabi-Yau n-fold. This makes us conjecture the existence of a quadrality symmetry in 0d. Finally, we comment on how the M-theory lift of brane brick models connects to the classification of 2d(0,2) theories in terms of 4-manifolds.

Edge diagnostics for tandem mirror machines

International Nuclear Information System (INIS)

Allen, S.L.

1984-01-01

The edge plasma in a tandem mirror machine shields the plasma core from cold neutral gas and impurities. A variety of diagnostics are used to measure the fueling, shielding, and confinement of the edge plasma in both the end plug and central cell regions. Fast ion gauges and residual gas analyzers measure the gas pressure and composition outside of the plasma. An array of Langmuir probes is used to measure the electron density and temperature. Extreme ultraviolet (euv) and visible spectroscopy are used to measure both the impurity and deuterium densities and to estimate the shielding factor for the core plasma. The linear geometry of a tandem mirror also allows direct measurements of the edge plasma by sampling the ions and electrons lost but the ends of the machine. Representative data obtained by these diagnostics during operation of the Tandem Mirror Experiment (TMX) and Tandem Mirror Experiment-Upgrade (TMX-U) experiments are presented. Diagnostics that are currently being developed to diagnose the edge plasma are also discussed

Fast force actuators for LSST primary/tertiary mirror

Science.gov (United States)

Hileman, Edward; Warner, Michael; Wiecha, Oliver

2010-07-01

The very short slew times and resulting high inertial loads imposed upon the Large Synoptic Survey Telescope (LSST) create new challenges to the primary mirror support actuators. Traditionally large borosilicate mirrors are supported by pneumatic systems, which is also the case for the LSST. These force based actuators bear the weight of the mirror and provide active figure correction, but do not define the mirror position. A set of six locating actuators (hardpoints) arranged in a hexapod fashion serve to locate the mirror. The stringent dynamic requirements demand that the force actuators must be able to counteract in real time for dynamic forces on the hardpoints during slewing to prevent excessive hardpoint loads. The support actuators must also maintain the prescribed forces accurately during tracking to maintain acceptable mirror figure. To meet these requirements, candidate pneumatic cylinders incorporating force feedback control and high speed servo valves are being tested using custom instrumentation with automatic data recording. Comparative charts are produced showing details of friction, hysteresis cycles, operating bandwidth, and temperature dependency. Extremely low power actuator controllers are being developed to avoid heat dissipation in critical portions of the mirror and also to allow for increased control capabilities at the actuator level, thus improving safety, performance, and the flexibility of the support system.

X-ray telescope mirrors made of slumped glass sheets

Science.gov (United States)

Winter, A.; Breunig, E.; Friedrich, P.; Proserpio, L.

2017-11-01

For several decades, the field of X-ray astronomy has been playing a major role in understanding the processes in our universe. From binary stars and black holes up to galaxy clusters and dark matter, high energetic events have been observed and analysed using powerful X-ray telescopes like e.g. Rosat, Chandra, and XMM-Newton [1,2,3], giving us detailed and unprecedented views of the high-energy universe. In November 2013, the theme of "The Hot and Energetic Universe" was rated as of highest importance for future exploration and in June 2014 the ATHENA Advanced Telescope for High Energy Astrophysics was selected by ESA for the second large science mission (L2) in the ESA Cosmic Vision program, with launch foreseen in 2028 [4]. By combining a large X-ray telescope with state-of-the-art scientific instruments, ATHENA will address key questions in astrophysics, including: How and why does ordinary matter assemble into the galaxies and galactic clusters that we see today? How do black holes grow and influence their surroundings? In order to answer these questions, ATHENA needs a powerful mirror system which exceed the capabilities of current missions, especially in terms of collecting area. However, current technologies have reached the mass limits of the launching rocket, creating the need for more light-weight mirror systems in order to enhance the effective area without increasing the telescope mass. Hence new mirror technologies are being developed which aim for low-weight systems with large collecting areas. Light material like glass can be used, which are shaped to form an X-ray reflecting system via the method of thermal glass slumping.

Distortion compensation in interferometric testing of mirrors

International Nuclear Information System (INIS)

Robinson, Brian M.; Reardon, Patrick J.

2009-01-01

We present a method to compensate for the imaging distortion encountered in interferometric testing of mirrors, which is introduced by interferometer optics as well as from geometric projection errors. Our method involves placing a mask, imprinted with a regular square grid, over the mirror and finding a transformation that relates the grid coordinates to coordinates in the base plane of the parent surface. This method can be used on finished mirrors since no fiducials have to be applied to the surfaces. A critical step in the process requires that the grid coordinates be projected onto the mirror base plane before the regression is performed. We apply the method successfully during a center-of-curvature null test of an F/2 off-axis paraboloid

Mirror Neurons from Associative Learning

OpenAIRE

Catmur, Caroline; Press, Clare; Heyes, Cecilia

2016-01-01

Mirror neurons fire both when executing actions and observing others perform similar actions. Their sensorimotor matching properties have generally been considered a genetic adaptation for social cognition; however, in the present chapter we argue that the evidence in favor of this account is not compelling. Instead we present evidence supporting an alternative account: that mirror neurons’ matching properties arise from associative learning during individual development. Notably, this proces...

X-ray microfocusing with off-axis ellipsoidal mirror

Energy Technology Data Exchange (ETDEWEB)

Yumoto, Hirokatsu, E-mail: yumoto@spring8.or.jp; Koyama, Takahisa [Japan Synchrotron Radiation Research Institute/SPring-8, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Matsuyama, Satoshi; Yamauchi, Kazuto [Department of Precision Science and Technology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Kohmura, Yoshiki; Ishikawa, Tetsuya [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Ohashi, Haruhiko [Japan Synchrotron Radiation Research Institute/SPring-8, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan)

2016-07-27

High-precision ellipsoidal mirrors for two-dimensionally focusing X-rays to nanometer sizes have not been realized because of technical problems in their fabrication processes. The objective of the present study is to develop fabrication techniques for ellipsoidal focusing mirrors in the hard-X-ray region. We design an off-axis ellipsoidal mirror for use under total reflection conditions up to the X-ray energy of 8 keV. We fabricate an ellipsoidal mirror with a surface roughness of 0.3 nm RMS (root-mean-square) and a surface figure error height of 3.0 nm RMS by utilizing a surface profiler and surface finishing method developed by us. The focusing properties of the mirror are evaluated at the BL29XUL beamline in SPring-8. A focusing beam size of 270 nm × 360 nm FWHM (full width at half maximum) at an X-ray energy of 7 keV is observed with the use of the knife-edge scanning method. We expect to apply the developed fabrication techniques to construct ellipsoidal nanofocusing mirrors.

Are mirror neurons the basis of speech perception? Evidence from five cases with damage to the purported human mirror system

Science.gov (United States)

Rogalsky, Corianne; Love, Tracy; Driscoll, David; Anderson, Steven W.; Hickok, Gregory

2013-01-01

The discovery of mirror neurons in macaque has led to a resurrection of motor theories of speech perception. Although the majority of lesion and functional imaging studies have associated perception with the temporal lobes, it has also been proposed that the ‘human mirror system’, which prominently includes Broca’s area, is the neurophysiological substrate of speech perception. Although numerous studies have demonstrated a tight link between sensory and motor speech processes, few have directly assessed the critical prediction of mirror neuron theories of speech perception, namely that damage to the human mirror system should cause severe deficits in speech perception. The present study measured speech perception abilities of patients with lesions involving motor regions in the left posterior frontal lobe and/or inferior parietal lobule (i.e., the proposed human ‘mirror system’). Performance was at or near ceiling in patients with fronto-parietal lesions. It is only when the lesion encroaches on auditory regions in the temporal lobe that perceptual deficits are evident. This suggests that ‘mirror system’ damage does not disrupt speech perception, but rather that auditory systems are the primary substrate for speech perception. PMID:21207313

Cryogenic Active Mirrors

Data.gov (United States)

National Aeronautics and Space Administration — This effort seeks to develop active mirrors that can correct for thermally-induced figure deformations upon cooling from room-temperature at the time of manufacture,...

Design of the GOES Telescope secondary mirror mounting

Science.gov (United States)

Hookman, Robert A.

1989-01-01

The GOES Telescope utilizes a flexure mounting system for the secondary mirror to minimize thermally induced distortions of the secondary mirror. The detailed design is presented along with a discussion of the microradian pointing requirements and how they were achieved. The methodology used to dynamically tune the flexure/secondary mirror assembly to minimize structural interactions will also be discussed.

The mirror system in human and nonhuman primates.

Science.gov (United States)

Orban, Guy A

2014-04-01

The description of the mirror neuron system provided by Cook et al. is incomplete for the macaque, and incorrect for humans. This is relevant to exaptation versus associative learning as the underlying mechanism generating mirror neurons, and to the sensorimotor learning as evidence for the authors' viewpoint. The proposed additional testing of the mirror system in rodents is unrealistic.

Discourse as mediator in environmental education in a natural science class: a case study

Directory of Open Access Journals (Sweden)

Marta Massa

2004-08-01

Full Text Available Discourse is an educational practice through which students and teachers are related by a sequence of meanings that are expressed, interchanged, negociated and constructed in the dynamic of a class. In this article, we analize the discursive practices and the arguments that are stated during a Science class when the teacher and her students discuss about the concepts “drinkable water – pollute water” when they are dealing with Environmental Education contents. A qualitative research within the perspective of a case study, centred on discourse analysis, was performed. We examine the content, the resources and the structural features that are used by the teacher and the students in order to construct the arguments and to establish the ideas. Two different templates were detected: the teacher’s, is based on perceptions and operative concepts, while the student’s one is organized in order to seek a microscopic explanation. Nevertheless, negotiation between these two perspectives fails during the dialogic interaction.

Mirror neurons: Enigma of the metaphysical modular brain.

Science.gov (United States)

Acharya, Sourya; Shukla, Samarth

2012-07-01

Mirror neurons are one of the most important discoveries in the last decade of neuroscience. These are a variety of visuospatial neurons which indicate fundamentally about human social interaction. Essentially, mirror neurons respond to actions that we observe in others. The interesting part is that mirror neurons fire in the same way when we actually recreate that action ourselves. Apart from imitation, they are responsible for myriad of other sophisticated human behavior and thought processes. Defects in the mirror neuron system are being linked to disorders like autism. This review is a brief introduction to the neurons that shaped our civilization.

Development in LIYaF of the method of polarized thermal neutron beam production by mirror reflection

International Nuclear Information System (INIS)

Borovikova, N.V.; Bulkin, A.P.; Gukasov, A.G.

1980-01-01

Main stages of development of polarizing neutron guide equipment in LIYaF of the USSR Academy of Sciences are described. To carry out experiments on solid-state physics constructed was a working mock-up of a polarizing neutron guide having 1570 mm length of a mirror channel. Successful application of polarizing mirrors to the working mock-up permitted to develop and fabricate five-meter polarizing neutron guide with output flux equal to 1.5x10 7 neutr/cm 2 xs. The following stage of development of polarizing neutron guides was the construction of four-meter neutron guide at the WWR-M reactor with output flux equal to the highest possible. Improvement of optical sections geometry made it possible to produce integral flux of 6.0x10 7 neutr/cm 2 xs in this neutron guide at 15 MW reactor power. The results obtained testify to prospects of the mirror method for polarization of thermal neutrons of a wave length lambda >= A. Neutron guides-polarizators permit to produce high fluxes of polarized thermal neutrons in the wide interval of wave length [ru

Adaptive aberration correction using a triode hyperbolic electron mirror

International Nuclear Information System (INIS)

Fitzgerald, J.P.S.; Word, R.C.; Koenenkamp, R.

2011-01-01

A converging electron mirror can be used to compensate spherical and chromatic aberrations in an electron microscope. This paper presents an analytical solution to a novel triode (three electrode) hyperbolic mirror as an improvement to the well-known diode (two electrode) hyperbolic mirror for aberration correction. A weakness of the diode mirror is a lack of flexibility in changing the chromatic and spherical aberration coefficients independently without changes in the mirror geometry. In order to remove this limitation, a third electrode can be added. We calculate the optical properties of the resulting triode mirror analytically on the basis of a simple model field distribution. We present the optical properties-the object/image distance, z 0 , and the coefficients of spherical and chromatic aberration, C s and C c , of both mirror types from an analysis of electron trajectories in the mirror field. From this analysis, we demonstrate that while the properties of both designs are similar, the additional parameters in the triode mirror improve the range of aberration that can be corrected. The triode mirror is also able to provide a dynamic adjustment range of chromatic aberration for fixed spherical aberration and focal length, or any permutation of these three parameters. While the dynamic range depends on the values of aberration correction needed, a nominal 10% tuning range is possible for most configurations accompanied by less than 1% change in the other two properties. -- Highlights: → Electrostatic aberration correction for chromatic and spherical aberration in electron optics. → Simultaneous correction of spherical and chromatic aberrations over a wide, adjustable range. → Analytic and quantitative description of correction parameters.

Distributed sensing signal analysis of deformable plate/membrane mirrors

Science.gov (United States)

Lu, Yifan; Yue, Honghao; Deng, Zongquan; Tzou, Hornsen

2017-11-01

Deformable optical mirrors usually play key roles in aerospace and optical structural systems applied to space telescopes, radars, solar collectors, communication antennas, etc. Limited by the payload capacity of current launch vehicles, the deformable mirrors should be lightweight and are generally made of ultra-thin plates or even membranes. These plate/membrane mirrors are susceptible to external excitations and this may lead to surface inaccuracy and jeopardize relevant working performance. In order to investigate the modal vibration characteristics of the mirror, a piezoelectric layer is fully laminated on its non-reflective side to serve as sensors. The piezoelectric layer is segmented into infinitesimal elements so that microscopic distributed sensing signals can be explored. In this paper, the deformable mirror is modeled as a pre-tensioned plate and membrane respectively and sensing signal distributions of the two models are compared. Different pre-tensioning forces are also applied to reveal the tension effects on the mode shape and sensing signals of the mirror. Analytical results in this study could be used as guideline of optimal sensor/actuator placement for deformable space mirrors.

Rise to SUMMIT: the Sydney University Multiple-Mirror Telescope

Science.gov (United States)

Moore, Anna M.; Davis, John

2000-07-01

The Sydney University Multiple Mirror Telescope (SUMMIT) is a medium-sized telescope designed specifically for high resolution stellar spectroscopy. Throughout the design emphasis has been placed on high efficiency at low cost. The telescope consists of four 0.46 m diameter mirrors mounted on a single welded steel frame. Specially designed mirror cells support and point each mirror, allowing accurate positioning of the images on optical fibers located at the foci of the mirrors. Four fibers convey the light to the future location of a high resolution spectrograph away from the telescope in a stable environment. An overview of the commissioning of the telescope is presented, including the guidance and automatic mirror alignment and focussing systems. SUMMIT is located alongside the Sydney University Stellar Interferometer at the Paul Wild Observatory, near Narrabri, Northern New South Wales.

Monitoring of absolute mirror alignment at COMPASS RICH-1 detector

Energy Technology Data Exchange (ETDEWEB)

Alexeev, M. [INFN, Sezione di Torino and University of East Piemonte, Alessandria (Italy); INFN, Sezione di Trieste and University of Bari, Bari (Italy); Birsa, R. [INFN, Sezione di Trieste, Trieste (Italy); Bradamante, F.; Bressan, A. [INFN, Sezione di Trieste and University of Trieste, Trieste (Italy); Chiosso, M. [INFN, Sezione di Torino and University of Torino, Torino (Italy); Ciliberti, P. [INFN, Sezione di Trieste and University of Trieste, Trieste (Italy); Dalla Torre, S. [INFN, Sezione di Trieste, Trieste (Italy); Denisov, O. [INFN, Sezione di Torino, Torino (Italy); Duic, V. [INFN, Sezione di Trieste and University of Trieste, Trieste (Italy); Ferrero, A. [INFN, Sezione di Torino and University of Torino, Torino (Italy); Finger, M.; Finger, M. [Charles University, Prague (Czech Republic); JINR, Dubna (Russian Federation); Gayde, J.Ch. [CERN, European Organization for Nuclear Research, Geneva (Switzerland); Giorgi, M. [INFN, Sezione di Trieste and University of Trieste, Trieste (Italy); Gobbo, B.; Levorato, S. [INFN, Sezione di Trieste, Trieste (Italy); Maggiora, A. [INFN, Sezione di Torino, Torino (Italy); Martin, A. [INFN, Sezione di Trieste and University of Trieste, Trieste (Italy); Menon, G. [INFN, Sezione di Trieste, Trieste (Italy); Panzieri, D. [INFN, Sezione di Torino and University of East Piemonte, Alessandria (Italy); and others

2014-12-01

The gaseous COMPASS RICH-1 detector uses two spherical mirror surfaces, segmented into 116 individual mirrors, to focus the Cherenkov photons onto the detector plane. Any mirror misalignment directly affects the detector resolution. The on-line Continuous Line Alignment and Monitoring (CLAM) photogrammetry-based method has been implemented to measure the alignment of individual mirrors which can be characterized by the center of curvature. The mirror wall reflects a regular grid of retroreflective strips placed inside the detector vessel. Then, the position of each mirror is determined from the image of the grid reflection. The images are collected by four cameras. Any small mirror misalignment results in changes of the grid lines’ positions in the image. The accuracy limits of the CLAM method were checked by laser interferometry and are below 0.1 mrad.

Mechanical-engineering aspects of mirror-fusion technology

International Nuclear Information System (INIS)

Fisher, D.K.; Doggett, J.N.

1982-01-01

The mirror approach to magnetic fusion has evolved from the original simple mirror cell to today's mainline effort: the tandem-mirror machine with thermal barriers. Physics and engineering research is being conducted throughout the world, with major efforts in Japan, the USSR, and the US. At least one facility under construction (MFTF-B) will approach equivalent energy breakeven in physics performance. Significant mechanical engineering development is needed, however, before a demonstration reactor can be constructed. The principal areas crucial to mirror reactor development include large high-field superconducting magnets, high-speed continuous vacuum-pumping systems, long-pulse high-power neutral-beam and rf-plasma heating systems, and efficient high-voltage high-power direct converters. Other areas common to all fusion systems include tritium handling technology, first-wall materials development, and fusion blanket design

Foil Panel Mirrors for Nonimaging Applications

Science.gov (United States)

Kuyper, D. J.; Castillo, A. A.

1984-01-01

Large durable, lightweight mirrors made by bonding thick aluminum foil to honeycomb panels or other rigid, flat backings. Mirrors suitable for use as infrared shields, telescope doors, solar-furnance doors, advertising displays, or other reflectors that require low thermal emissivity and high specularity but do not require precise surface figure necessary for imaging.

Status of the mirror-next-step (MNS) study

International Nuclear Information System (INIS)

Damm, C.C.; Doggett, J.N.; Bulmer, R.H.

1979-09-01

A study was made to define the features of the experimental mirror fusion device - the Mirror Next Step, or MNS - that will bridge the gap between present mirror confinement experiments and a power-producing reactor. The project goals and organization of the study are outlined, some initial device parameters are described, and the technological requirements are related to ongoing development programs

车载系统MirrorLink方案的研究%Research of head-unit MirrorLink solution

Institute of Scientific and Technical Information of China (English)

张元文; 陈玮

2013-01-01

介绍了车载系统的MirrorLink方案,分析了它的协议架构,对其两个主要内容——VNC架构和音视频传输架构做了介绍.分析了VNC架构中的核心RFB协议的过程和实现,RFB协议是负责MirrorLink系统中的界面传输和控制信号的传递,对它的编码要求进行分析,提出了更加优化的编码方式；在音视频架构中,提出了一种改进的可应用于车载MirrorLink中的UPnp视音频传输方案.%This paper presents the ear' s MirrorLink solution,analyses the protocol architecture. It simply introduced the two main content-VNC architecture and audio & video transmission architecture. In VNC architecture introduced the core protocol-RFB protocol implementation, it used to transfer the HMI screen and the control signals, analyzed coding requirements and proposed more optimized coding methods. In audio & video transmission architecture it proposed an improved UPnp video and audio transmission scheme ,it can be applied to the vehicle MirrorLink solution.

Development of in situ cleaning techniques for diagnostic mirrors in ITER

International Nuclear Information System (INIS)

Litnovsky, A.; Laengner, M.; Matveeva, M.; Schulz, Ch.; Marot, L.; Voitsenya, V.S.; Philipps, V.; Biel, W.; Samm, U.

2011-01-01

Mirrors will be used in all optical and laser-based diagnostic systems of ITER. In the severe environment, the optical characteristics of mirrors will be degraded, hampering the entire performance of the respective diagnostics. A minute impurity deposition of 20 nm of carbon on the mirror is sufficient to decrease the mirror reflectivity by tens of percent outlining the necessity of the mirror cleaning in ITER. The results of R and D on plasma cleaning of molybdenum diagnostic mirrors are reported. The mirrors contaminated with amorphous carbon films in the laboratory conditions and in the tokamaks were cleaned in steady-state hydrogenic plasmas. The maximum cleaning efficiency of 4.2 nm/min was reached for the laboratory and soft tokamak hydrocarbon films, whereas for the hard tokamak films the carbidization of mirrors drastically decreased the cleaning efficiency down to 0.016 nm/min. This implies the necessity of sputtering cleaning of contaminated mirrors as the only reliable tool to remove the deposits by plasma cleaning. An overview of R and D program on mirror cleaning is provided along with plans for further studies and the recommendations for ITER mirror-based diagnostics.

Mirror position determination for the alignment of Cherenkov Telescopes

Energy Technology Data Exchange (ETDEWEB)

Adam, J. [TU Dortmund, Experimental Physics 5 Otto-Hahn-Str. 4, 44221 Dortmund (Germany); Ahnen, M.L. [ETH Zurich, Institute for Particle Physics Otto-Stern-Weg 5, 8093 Zurich (Switzerland); Baack, D. [TU Dortmund, Experimental Physics 5 Otto-Hahn-Str. 4, 44221 Dortmund (Germany); Balbo, M. [University of Geneva, ISDC Data Center for Astrophysics Chemin Ecogia 16, 1290 Versoix (Switzerland); Bergmann, M. [Universität Würzburg, Institute for Theoretical Physics and Astrophysics Emil-Fischer-Str. 31, 97074 Würzburg (Germany); Biland, A. [ETH Zurich, Institute for Particle Physics Otto-Stern-Weg 5, 8093 Zurich (Switzerland); Blank, M. [Universität Würzburg, Institute for Theoretical Physics and Astrophysics Emil-Fischer-Str. 31, 97074 Würzburg (Germany); Bretz, T. [ETH Zurich, Institute for Particle Physics Otto-Stern-Weg 5, 8093 Zurich (Switzerland); RWTH Aachen (Germany); Bruegge, K.A.; Buss, J. [TU Dortmund, Experimental Physics 5 Otto-Hahn-Str. 4, 44221 Dortmund (Germany); Dmytriiev, A. [University of Geneva, ISDC Data Center for Astrophysics Chemin Ecogia 16, 1290 Versoix (Switzerland); Domke, M. [TU Dortmund, Experimental Physics 5 Otto-Hahn-Str. 4, 44221 Dortmund (Germany); Dorner, D. [Universität Würzburg, Institute for Theoretical Physics and Astrophysics Emil-Fischer-Str. 31, 97074 Würzburg (Germany); FAU Erlangen (Germany); Einecke, S. [TU Dortmund, Experimental Physics 5 Otto-Hahn-Str. 4, 44221 Dortmund (Germany); Hempfling, C. [Universität Würzburg, Institute for Theoretical Physics and Astrophysics Emil-Fischer-Str. 31, 97074 Würzburg (Germany); and others

2017-07-11

Imaging Atmospheric Cherenkov Telescopes (IACTs) need imaging optics with large apertures to map the faint Cherenkov light emitted in extensive air showers onto their image sensors. Segmented reflectors fulfill these needs using mass produced and light weight mirror facets. However, as the overall image is the sum of the individual mirror facet images, alignment is important. Here we present a method to determine the mirror facet positions on a segmented reflector in a very direct way. Our method reconstructs the mirror facet positions from photographs and a laser distance meter measurement which goes from the center of the image sensor plane to the center of each mirror facet. We use our method to both align the mirror facet positions and to feed the measured positions into our IACT simulation. We demonstrate our implementation on the 4 m First Geiger-mode Avalanche Cherenkov Telescope (FACT).

Performance of The Far Ultraviolet Spectroscopic Explorer Mirror Assemblies

Science.gov (United States)

Ohi, Raymond G.; Barkhouser, Robert H.; Conard, Steven J.; Friedman, Scott D.; Hampton, Jeffery; Moos, H. Warren; Nikulla, Paul; Oliveira, Cristina M.; Saha, Timo T.; Obenschain, Arthur (Technical Monitor)

2000-01-01

The Far Ultraviolet Spectroscopic Explorer is a NASA astrophysics satellite which produces high-resolution spectra in the far-ultraviolet (90.5-118.7 nm bandpass) using a high effective area and low background detectors. The observatory was launched on its three-year mission from Cape Canaveral Air Station on 24 June 1999. The instrument contains four coaligned, normal incidence, off-axis parabolic mirrors which illuminate separate Rowland circle spectrograph channels equipped with holographically ruled diffraction gratings and delay line microchannel plate detectors. The telescope mirrors have a 352 x 387 mm aperture and 2245 mm focal length and are attached to actuator assemblies, which provide on-orbit, tip, tilt, and focus control. Two mirrors are coated with silicon carbide (SiC) and two are coated with lithium fluoride over aluminum (Al:LiF). We describe mirror assembly in-flight optical and mechanical performance. On-orbit measurements of the far-ultraviolet point spread function associated with each mirror are compared to expectations based on pre-flight laboratory measurements and modeling using the Optical Surface Analysis Code and surface metrology data. On-orbit imaging data indicate that the mirrors meet their instrument-level requirement of 50 percent and 95 percent slit transmission for the high- and mid-resolution spectrograph entrance slits, respectively. The degradation of mirror reflectivity during satellite integration and test is also discussed. The far-ultraviolet reflectivity of the SiC- and AlLiF-coated mirrors decreased about six percent and three percent, respectively, between coating and launch. Each mirror is equipped with three actuators, which consist of a stepper motor driving a ball screw via a two-stage planetary gear train. We also discuss the mechanical performance of the mirror assemblies, including actuator performance and thermal effects.

Scattering-free optical levitation of a cavity mirror.

Science.gov (United States)

Guccione, G; Hosseini, M; Adlong, S; Johnsson, M T; Hope, J; Buchler, B C; Lam, P K

2013-11-01

We demonstrate the feasibility of levitating a small mirror using only radiation pressure. In our scheme, the mirror is supported by a tripod where each leg of the tripod is a Fabry-Perot cavity. The macroscopic state of the mirror is coherently coupled to the supporting cavity modes allowing coherent interrogation and manipulation of the mirror motion. The proposed scheme is an extreme example of the optical spring, where a mechanical oscillator is isolated from the environment and its mechanical frequency and macroscopic state can be manipulated solely through optical fields. We model the stability of the system and find a three-dimensional lattice of trapping points where cavity resonances allow for buildup of optical field sufficient to support the weight of the mirror. Our scheme offers a unique platform for studying quantum and classical optomechanics and can potentially be used for precision gravitational field sensing and quantum state generation.

Mirror Lake: Past, present and future: Chapter 6

Science.gov (United States)

Likens, Gene E.; LaBaugh, James W.; Winter, Thomas C.; Likens, Gene E.

2009-01-01

This chapter discusses the hydrological and biogeochemical characteristics of Mirror Lake and the changes that resulted from air-land-water interactions and human activities. Since the formation of Mirror Lake, both the watershed and the lake have undergone many changes, such as vegetation development and basin filling. These changes are ongoing, and Mirror Lake is continuing along an aging pathway and ultimately, it will fill with sediment and no longer be a lake. The chapter also identifies major factors that affected the hydrology and biogeochemistry of Mirror Lake: acid rain, atmospheric deposition of lead and other heavy metals, increased human settlement around the lake, the construction of an interstate highway through the watershed of the Northeast Tributary, the construction of an access road through the West and Northeast watersheds to the lake, and climate change. The chapter also offers future recommendations for management and protection of Mirror Lake.

Action observation and mirror neuron network: a tool for motor stroke rehabilitation.

Science.gov (United States)

Sale, P; Franceschini, M

2012-06-01

Mirror neurons are a specific class of neurons that are activated and discharge both during observation of the same or similar motor act performed by another individual and during the execution of a motor act. Different studies based on non invasive neuroelectrophysiological assessment or functional brain imaging techniques have demonstrated the presence of the mirror neuron and their mechanism in humans. Various authors have demonstrated that in the human these networks are activated when individuals learn motor actions via execution (as in traditional motor learning), imitation, observation (as in observational learning) and motor imagery. Activation of these brain areas (inferior parietal lobe and the ventral premotor cortex, as well as the caudal part of the inferior frontal gyrus [IFG]) following observation or motor imagery may thereby facilitate subsequent movement execution by directly matching the observed or imagined action to the internal simulation of that action. It is therefore believed that this multi-sensory action-observation system enables individuals to (re) learn impaired motor functions through the activation of these internal action-related representations. In humans, the mirror mechanism is also located in various brain segment: in Broca's area, which is involved in language processing and speech production and not only in centres that mediate voluntary movement, but also in cortical areas that mediate visceromotor emotion-related behaviours. On basis of this finding, during the last 10 years various studies were carry out regarding the clinical use of action observation for motor rehabilitation of sub-acute and chronic stroke patients.

Variable area manifolds for ring mirror heat exchangers

Science.gov (United States)

Eng, Albert; Senterfitt, Donald R.

1988-05-01

A laser ring mirror assembly is disclosed which supports and cools an annular ring mirror of a high powered laser with a cooling manifold which has a coolant flow design which is intended to reduce thermal distortions of the ring mirror by minimizing azimuthal variations in temperature around its circumference. The cooling manifold has complementary pairs of cooling passages each of which conduct coolant in opposite flow directions. The manifold also houses adjusters which vary the depth between the annular ring mirror and each cooling, and which vary the flow area of the cooling passage to produce a control over the cooling characteristics of the cooling manifold.

Design of tandem mirror reactors with thermal barriers

International Nuclear Information System (INIS)

Carlson, G.A.

1980-01-01

End-plug technologies for tandem mirror reactors include high-field superconducting magnets, neutral beam injectors, and gyrotrons for electron cyclotron resonant heating (ECRH). In addition to their normal use for sustenance of the end-plug plasmas, neutral beam injectors are used for ''pumping'' trapped ions from the thermal barrier regions by charge exchange. An extra function of the axially directed pump beams is the removal of thermalized alpha particles from the reactor. The principles of tandem mirror operation with thermal barriers will be demonstrated in the upgrade of the Tandem Mirror Experiment (TMX-U) in 1981 and the tandem configuration of the Mirror fusion Test Facility (MFTF-B) in 1984

Thermal performance of the ATST secondary mirror

Science.gov (United States)

Cho, Myung K.; DeVries, Joe; Hansen, Eric

2007-12-01

The Advanced Technology Solar Telescope (ATST) has a 4.24m off-axis primary mirror designed to deliver diffractionlimited images of the sun. Its baseline secondary mirror (M2) design uses a 0.65m diameter Silicon Carbide mirror mounted kinematically by a bi-pod flexure mechanism at three equally spaced locations. Unlike other common telescopes, the ATST M2 is to be exposed to a significant solar heat loading. A thermal management system (TMS) will be developed to accommodate the solar loading and minimize "mirror seeing effect" by controlling the temperature difference between the M2 optical surface and the ambient air at the site. Thermo-elastic analyses for steady state thermal behaviors of the ATST secondary mirror was performed using finite element analysis by I-DEAS TM and PCRINGE TM for the optical analysis. We examined extensive heat transfer simulation cases and their results were discussed. The goal of this study is to establish thermal models by I-DEAS for an adequate thermal environment. These thermal models will be useful for estimating segment thermal responses. Current study assumes a few sample time dependent thermal loadings to synthesize the operational environment.

Performance evaluations of the ATST secondary mirror

Science.gov (United States)

Cho, Myung K.; DeVries, Joseph; Hansen, Eric

2007-09-01

The Advanced Technology Solar Telescope (ATST) has a 4.24m off-axis primary mirror designed to deliver diffraction-limited images of the sun. Its baseline secondary mirror (M2) design uses a 0.65m diameter Silicon Carbide mirror mounted kinematically by a bi-pod flexure mechanism at three equally spaced locations. Unlike other common telescopes, the ATST M2 is to be exposed to a significant solar heat loading. A thermal management system will be developed to accommodate the solar loading and minimize "mirror seeing effect" by controlling the temperature difference between the M2 optical surface and the ambient air at the site. Thermo-elastic analyses for steady state thermal behaviors of the ATST secondary mirror was performed using finite element analysis by I-DEAS TM and PCFRINGE TM for the optical analysis. We examined extensive heat transfer simulation cases and their results are discussed. The goal of this study is to evaluate the optical performances of M2 using thermal models and mechanical models. Thermal responses from the models enable us to manipulate time dependent thermal loadings to synthesize the operational environment for the design and development of TMS.

Design and fabrication of soft x-ray mirrors

Energy Technology Data Exchange (ETDEWEB)

Kawata, Masaru; Sasai, Hiroyuki; Sano, Kazuo [Shimadzu Corp., Production Engineering Laboratory, Kyoto (Japan)

2000-03-01

Soft x-ray photoelectron spectroscopic technology is important for measuring the chemical status of material surface in the LSI manufacturing process. We report on non-spherical mirrors focusing laser-induced plasma soft x-ray to fine sample surface. We designed toric and ellipsoidal mirror as soft x-ray condensing means, simulated focusing image, manufactured mirror surface on fused quartz substrate, and measured form accuracy. (author)

Strongly-interacting mirror fermions at the LHC

Directory of Open Access Journals (Sweden)

Triantaphyllou George

2017-01-01

Full Text Available The introduction of mirror fermions corresponding to an interchange of leftwith right-handed fermion quantum numbers of the Standard Model can lead to a model according to which the BEH mechanism is just an effective manifestation of a more fundamental theory while the recently-discovered Higgs-like particle is composite. This is achieved by a non-abelian gauge symmetry encompassing three mirror-fermion families strongly coupled at energies near 1 TeV. The corresponding non-perturbative dynamics lead to dynamical mirror-fermion masses between 0.14 - 1.2 TeV. Furthermore, one expects the formation of composite states, i.e. “mirror mesons”, with masses between 0.1 and 3 TeV. The number and properties of the resulting new degrees of freedom lead to a rich and interesting phenomenology, part of which is analyzed in the present work.

Mirror Advanced Reactor Study interim design report

Energy Technology Data Exchange (ETDEWEB)

1983-04-01

The status of the design of a tenth-of-a-kind commercial tandem-mirror fusion reactor is described at the midpoint of a two-year study. When completed, the design is to serve as a strategic goal for the mirror fusion program. The main objectives of the Mirror Advanced Reactor Study (MARS) are: (1) to design an attractive tandem-mirror fusion reactor producing electricity and synfuels (in alternate versions), (2) to identify key development and technology needs, and (3) to exploit the potential of fusion for safety, low activation, and simple disposal of radioactive waste. In the first year we have emphasized physics and engineering of the central cell and physics of the end cell. Design optimization and trade studies are continuing, and we expect additional modifications in the end cells to further improve the performance of the final design.

Mirror Advanced Reactor Study interim design report

International Nuclear Information System (INIS)

1983-04-01

The status of the design of a tenth-of-a-kind commercial tandem-mirror fusion reactor is described at the midpoint of a two-year study. When completed, the design is to serve as a strategic goal for the mirror fusion program. The main objectives of the Mirror Advanced Reactor Study (MARS) are: (1) to design an attractive tandem-mirror fusion reactor producing electricity and synfuels (in alternate versions), (2) to identify key development and technology needs, and (3) to exploit the potential of fusion for safety, low activation, and simple disposal of radioactive waste. In the first year we have emphasized physics and engineering of the central cell and physics of the end cell. Design optimization and trade studies are continuing, and we expect additional modifications in the end cells to further improve the performance of the final design

Wolter type I x-ray focusing mirror using multilayer coatings

International Nuclear Information System (INIS)

Chon, Kwon Su; Namba, Yoshiharu; Yoon, Kwon-Ha

2006-01-01

A multilayer coating is a useful addition to a mirror in the x-ray region and has been applied to normal incidence mirrors used with soft x rays. When a multilayer coating is used on grazing incidence optics, higher performance can be achieved than without it.Cr/Sc multilayers coated on a Wolter type I mirror substrate for a soft x-ray microscope are considered. The reflectivity and effective solid angle are calculated for Wolter type I mirrors with uniform and laterally graded multilayer coatings. The laterally graded multilayer mirror showed superior x-ray performance, and the multilayer tolerances were relaxed. This multilayer mirror could be especially useful in the soft x-ray microscope intended for biological applications

Calibration of the mirror system in the HERA-B RICH

International Nuclear Information System (INIS)

Staric, Marko; Krizan, Peter

2008-01-01

The mirror system of the HERA-B ring imaging Cherenkov (RICH) counter consists of two spherical and two planar mirrors, composed of altogether 116 mirror segments. Analysis of displacements of the Cherenkov ring center relative to the charged particle track, for given spherical-planar segment pairs, leads to accurate information regarding the orientation of individual mirror segments. The method for mirror calibration is described and the effect of applying the required corrections on the Cherenkov angle resolution of the HERA-B RICH is discussed

Screening of a virtual mirror-image library of natural products.

Science.gov (United States)

Noguchi, Taro; Oishi, Shinya; Honda, Kaori; Kondoh, Yasumitsu; Saito, Tamio; Ohno, Hiroaki; Osada, Hiroyuki; Fujii, Nobutaka

2016-06-08

We established a facile access to an unexplored mirror-image library of chiral natural product derivatives using d-protein technology. In this process, two chemical syntheses of mirror-image substances including a target protein and hit compound(s) allow the lead discovery from a virtual mirror-image library without the synthesis of numerous mirror-image compounds.

EUV multilayer mirror, optical system including a multilayer mirror and method of manufacturing a multilayer mirror

NARCIS (Netherlands)

Huang, Qiushi; Louis, Eric; Bijkerk, Frederik; de Boer, Meint J.; von Blanckenhagen, G.

2016-01-01

A multilayer mirror (M) reflecting extreme ultraviolet (EUV) radiation from a first wave-length range in a EUV spectral region comprises a substrate (SUB) and a stack of layers (SL) on the substrate, the stack of layers comprising layers comprising a low index material and a high index material, the

Manufacturing parabolic mirrors

CERN Multimedia

CERN PhotoLab

1975-01-01

The photo shows the construction of a vertical centrifuge mounted on an air cushion, with a precision of 1/10000 during rotation, used for the manufacture of very high=precision parabolic mirrors. (See Annual Report 1974.)

Mirror model for sterile neutrinos

International Nuclear Information System (INIS)

Berezinsky, Veniamin; Narayan, Mohan; Vissani, Francesco

2003-01-01

Sterile neutrinos are studied as subdominant contribution to solar neutrino physics. The mirror-matter neutrinos are considered as sterile neutrinos. We use the symmetric mirror model with gravitational communication between mirror and visible sectors. This communication term provides mixing between visible and mirror neutrinos with the basic scale μ=v EW 2 /M Pl =2.5x10 -6 eV, where v EW =174 GeV is the vacuum expectation value of the standard electroweak group and M Pl is the Planckian mass. It is demonstrated that each mass eigenstate of active neutrinos splits into two states separated by small Δm 2 . Unsuppressed oscillations between active and sterile neutrinos (ν a ↔ν s ) occur only in transitions between each of these close pairs ('windows'). These oscillations are characterized by very small Δm 2 and can suppress the flux and distort spectrum of pp-neutrinos in detectable way. The other observable effect is anomalous seasonal variation of neutrino flux, which appears in LMA solution. The considered subdominant neutrino oscillations ν a ↔ν s can reveal itself as big effects in observations of supernova neutrinos and high-energy (HE) neutrinos. In the case of HE neutrinos they can provide a very large diffuse flux of active neutrinos unconstrained by the e-m cascade upper limit

Energy flow of electric dipole radiation in between parallel mirrors

Science.gov (United States)

Xu, Zhangjin; Arnoldus, Henk F.

2017-11-01

We have studied the energy flow patterns of the radiation emitted by an electric dipole located in between parallel mirrors. It appears that the field lines of the Poynting vector (the flow lines of energy) can have very intricate structures, including many singularities and vortices. The flow line patterns depend on the distance between the mirrors, the distance of the dipole to one of the mirrors and the angle of oscillation of the dipole moment with respect to the normal of the mirror surfaces. Already for the simplest case of a dipole moment oscillating perpendicular to the mirrors, singularities appear at regular intervals along the direction of propagation (parallel to the mirrors). For a parallel dipole, vortices appear in the neighbourhood of the dipole. For a dipole oscillating under a finite angle with the surface normal, the radiating tends to swirl around the dipole before travelling off parallel to the mirrors. For relatively large mirror separations, vortices appear in the pattern. When the dipole is off-centred with respect to the midway point between the mirrors, the flow line structure becomes even more complicated, with numerous vortices in the pattern, and tiny loops near the dipole. We have also investigated the locations of the vortices and singularities, and these can be found without any specific knowledge about the flow lines. This provides an independent means of studying the propagation of dipole radiation between mirrors.

Support mechanism for a mirrored surface or other arrangement

Science.gov (United States)

Cutburth, Ronald W.

1987-01-01

An adjustment mechanism such as a three point spherical mount for adjustably supporting a planer mirror or other type of arrangement relative to a plane defined by a given pair of intersecting perpendicular axes is disclosed herein. This mechanism includes first means for fixedly supporting the mirror or other arrangement such that the latter is positionable within the plane defined by the given pair of intersecting perpendicular axes. This latter means and the mirror or other such arrangement are supported by second means for limited movement back and forth about either of the intersecting axes. Moreover, this second means supports the first means and the mirror or other arrangement such that the latter is not movable in any other way whereby the point on the mirror or other arrangement coinciding with the intersection of the given axes does not move or float, thereby making the ability to adjust the mirror or other such arrangement more precise and accurate.

Plasma cleaning of ITER First Mirrors in magnetic field

Energy Technology Data Exchange (ETDEWEB)

Moser, Lucas, E-mail: lucas.moser@unibas.ch [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Steiner, Roland [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Leipold, Frank; Reichle, Roger [ITER Organization, Route de Vinon-sur-Verdon, 13115 St Paul-lez-Durance (France); Marot, Laurent; Meyer, Ernst [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland)

2015-08-15

To avoid reflectivity losses in ITER’s optical diagnostic systems, plasma sputtering of metallic First Mirrors is foreseen in order to remove deposits coming from the main wall (mainly beryllium and tungsten). Therefore plasma cleaning has to work on large mirrors (up to a size of 200 × 300 mm) and under the influence of strong magnetic fields (several Tesla). This work presents the results of plasma cleaning of aluminium and aluminium oxide (used as beryllium proxy) deposited on molybdenum mirrors. Using radio frequency (13.56 MHz) argon plasma, the removal of a 260 nm mixed aluminium/aluminium oxide film deposited by magnetron sputtering on a mirror (98 mm diameter) was demonstrated. 50 nm of pure aluminium oxide were removed from test mirrors (25 mm diameter) in a magnetic field of 0.35 T for various angles between the field lines and the mirrors surfaces. The cleaning efficiency was evaluated by performing reflectivity measurements, Scanning Electron Microscopy and X-ray Photoelectron Spectroscopy.

Laser beam-forming by deformable mirror for laser isotope separation

International Nuclear Information System (INIS)

Nemoto, Koshichi; Fujii, Takashi; Goto, Naohiko

1995-01-01

A rectangular laser beam of uniform intensity is very suitable for laser isotope separation. In this paper, we propose a beam-forming system which consists two deformable mirrors. One of the mirrors changes the beam intensity and the other compensates for phase distortion. We developed a deformable mirror for beam-forming. Its deformed surface is similar to the ideal mirror surface for beam-forming. We reshaped a Gaussian-like He-Ne laser beam into a beam with a more uniform intensity profile by a simple deformable mirror. (author)

Systems and methods for mirror mounting with minimized distortion

Science.gov (United States)

Antonille, Scott R. (Inventor); Wallace, Thomas E. (Inventor); Content, David A. (Inventor); Wake, Shane W. (Inventor)

2012-01-01

A method for mounting a mirror for use in a telescope includes attaching the mirror to a plurality of adjustable mounts; determining a distortion in the mirror caused by the plurality adjustable mounts, and, if the distortion is determined to be above a predetermined level: adjusting one or more of the adjustable mounts; and determining the distortion in the mirror caused by the adjustable mounts; and in the event the determined distortion is determined to be at or below the predetermined level, rigidizing the adjustable mounts.

Optimizing x-ray mirror thermal performance using variable length cooling for second generation FELs

Science.gov (United States)

Hardin, Corey L.; Srinivasan, Venkat N.; Amores, Lope; Kelez, Nicholas M.; Morton, Daniel S.; Stefan, Peter M.; Nicolas, Josep; Zhang, Lin; Cocco, Daniele

2016-09-01

The success of the LCLS led to an interest across a number of disciplines in the scientific community including physics, chemistry, biology, and material science. Fueled by this success, SLAC National Accelerator Laboratory is developing a new high repetition rate free electron laser, LCLS-II, a superconducting linear accelerator capable of a repetition rate up to 1 MHz. Undulators will be optimized for 200 to 1300 eV soft X-rays, and for 1000 to 5000 eV hard X-rays. To absorb spontaneous radiation, higher harmonic energies and deflect the x-ray beam to various end stations, the transport and diagnostics system includes grazing incidence plane mirrors on both the soft and Hard X-ray beamline. To deliver the FEL beam with minimal power loss and wavefront distortion, we need mirrors of height errors below 1nm rms in operational conditions. We need to mitigate the thermal load effects due to the high repetition rate. The absorbed thermal profile is highly dependent on the beam divergence, and this is a function of the photon energy. To address this complexity, we developed a mirror cradle with variable length cooling and first order curve correction. Mirror figure error is minimized using variable length water-cooling through a gallium-indium eutectic bath. Curve correction is achieved with an off-axis bender that will be described in details. We present the design features, mechanical analysis and results from optical and mechanical tests of a prototype assembly, with particular regards to the figure sensitivity to bender corrections.

Thermal-mechanical behavior of high precision composite mirrors

Science.gov (United States)

Kuo, C. P.; Lou, M. C.; Rapp, D.

1993-01-01

Composite mirror panels were designed, constructed, analyzed, and tested in the framework of a NASA precision segmented reflector task. The deformations of the reflector surface during the exposure to space enviroments were predicted using a finite element model. The composite mirror panels have graphite-epoxy or graphite-cyanate facesheets, separated by an aluminum or a composite honeycomb core. It is pointed out that in order to carry out detailed modeling of composite mirrors with high accuracy, it is necessary to have temperature dependent properties of the materials involved and the type and magnitude of manufacturing errors and material nonuniformities. The structural modeling and analysis efforts addressed the impact of key design and materials parameters on the performance of mirrors.

Fabrication of off-axis parabolic mirrors

International Nuclear Information System (INIS)

Bezik, M.J.; Gerth, H.L.; Sladky, R.E.; Washington, C.A.

1978-08-01

The report describes the fabrication process, including metal preparation, copper electroplating, single-crystal-diamond turning, optical inspection, and polishing, used to manufacture the focusing mirrors for the 10-kJ laser fusion experiment being conducted by the Los Alamos Scientific Laboratory. Fabrication of these mirrors by the techniques described resulted in diffraction-limited optics at a 10.6 μm wavelength

The mirror mechanism in the parietal lobe.

Science.gov (United States)

Rizzolatti, Giacomo; Rozzi, Stefano

2018-01-01

The mirror mechanism is a basic mechanism that transforms sensory representations of others' actions into motor representations of the same actions in the brain of the observer. The mirror mechanism plays an important role in understanding actions of others. In the present chapter we discuss first the basic organization of the posterior parietal lobe in the monkey, stressing that it is best characterized as a motor scaffold, on the top of which sensory information is organized. We then describe the location of the mirror mechanism in the posterior parietal cortex of the monkey, and its functional role in areas PFG, and anterior, ventral, and lateral intraparietal areas. We will then present evidence that a similar functional organization is present in humans. We will conclude by discussing the role of the mirror mechanism in the recognition of action performed with tools. Copyright © 2018 Elsevier B.V. All rights reserved.

The mirror mechanism: recent findings and perspectives

Science.gov (United States)

Rizzolatti, Giacomo; Fogassi, Leonardo

2014-01-01

Mirror neurons are a specific type of visuomotor neuron that discharge both when a monkey executes a motor act and when it observes a similar motor act performed by another individual. In this article, we review first the basic properties of these neurons. We then describe visual features recently investigated which indicate that, besides encoding the goal of motor acts, mirror neurons are modulated by location in space of the observed motor acts, by the perspective from which the others’ motor acts are seen, and by the value associated with the object on which others’ motor acts are performed. In the last part of this article, we discuss the role of the mirror mechanism in planning actions and in understanding the intention underlying the others’ motor acts. We also review some human studies suggesting that motor intention in humans may rely, as in the monkey, on the mirror mechanism. PMID:24778385

Long-trace profiler for neutron focusing mirrors

International Nuclear Information System (INIS)

Puzyrev, Yevgeniy S.; Ice, Gene E.; Takacs, Peter Z.

2009-01-01

A long-trace profiler (LTP) optimized for measuring the shape of large neutron supermirrors has been designed and built. This LTP can measure 1.6 m long mirrors in both vertically and horizontally deflecting geometries, which is essential to achieve best performance from bendable mirrors. The LTP suppresses the influence of angular deviations of the linear-stage carriage during translation with a pentaprism and a cylindrical lens. The stationary optical head and the carriage-mounted pentaprism are precisely aligned to rotate about the optical axis between the two components. This feature allows measurements to be made on mirrors mounted vertically, horizontally or at any angle in between. The LTP software allows for rapid optimization of parameters for dynamically bent elliptical mirrors. Here we describe the motivation for the LTP, the design, and a first application of the LTP to study the effect of gravity on a bent microfocusing neutron supermirror.

Coating considerations for mirrors of CPV devices

International Nuclear Information System (INIS)

Schmauder, Torsten; Sauer, Peter; Ickes, Gerd

2014-01-01

One of the different optical concepts for concentrator devices is to place a focussing primary mirror behind a transparent front plate. In addition (also in case of Fresnel-diffractive main optics), further 'secondary' reflectors may be used further along the beam path. Such mirrors are usually implemented as coating stacks of a highly reflective metal - usually silver - and protective layers. The protective layers are preferably designed as reflection enhancing interference stack. The design of such protective layer stacks yields two difficulties, which are addressed in this paper: (a) vacuum coating of three-dimensional parts will result in a thickness distribution and the optical design of the stack should thus be tolerant to layer thickness variations, and (b) different places of the mirror will have different angle-of-incidence of the sunlight under operating conditions. As result, the layer stack has a different design at different places of the mirror

Stability design considerations for mirror support systems in ICF lasers

International Nuclear Information System (INIS)

Tietbohl, G.L.; Sommer, S.C.

1996-10-01

Some of the major components of laser systems used for Inertial Confinement Fusion (ICF) are the large aperture mirrors which direct the path of the laser. These mirrors are typically supported by systems which consist of mirror mounts, mirror enclosures, superstructures, and foundations. Stability design considerations for the support systems of large aperture mirrors have been developed based on the experience of designing and evaluating similar systems at the Lawrence Livermore National Laboratory (LLNL). Examples of the systems developed at LLNL include Nova, the Petawatt laser, Beamlet, and the National Ignition Facility (NIF). The structural design of support systems of large aperture mirrors has typically been controlled by stability considerations in order for the large laser system to meet its performance requirements for alignment and positioning. This paper will discuss the influence of stability considerations and will provide guidance on the structural design and evaluation of mirror support systems in ICF lasers so that this information can be used on similar systems

Overview of deformable mirror technologies for adaptive optics and astronomy

Science.gov (United States)

Madec, P.-Y.

2012-07-01

From the ardent bucklers used during the Syracuse battle to set fire to Romans’ ships to more contemporary piezoelectric deformable mirrors widely used in astronomy, from very large voice coil deformable mirrors considered in future Extremely Large Telescopes to very small and compact ones embedded in Multi Object Adaptive Optics systems, this paper aims at giving an overview of Deformable Mirror technology for Adaptive Optics and Astronomy. First the main drivers for the design of Deformable Mirrors are recalled, not only related to atmospheric aberration compensation but also to environmental conditions or mechanical constraints. Then the different technologies available today for the manufacturing of Deformable Mirrors will be described, pros and cons analyzed. A review of the Companies and Institutes with capabilities in delivering Deformable Mirrors to astronomers will be presented, as well as lessons learned from the past 25 years of technological development and operation on sky. In conclusion, perspective will be tentatively drawn for what regards the future of Deformable Mirror technology for Astronomy.

Assessing does not mean threatening: the purpose of assessment as a key determinant of girls' and boys' performance in a science class.

Science.gov (United States)

Souchal, Carine; Toczek, Marie-Christine; Darnon, Céline; Smeding, Annique; Butera, Fabrizio; Martinot, Delphine

2014-03-01

Is it possible to reach performance equality between boys and girls in a science class? Given the stereotypes targeting their groups in scientific domains, diagnostic contexts generally lower girls' performance and non-diagnostic contexts may harm boys' performance. The present study tested the effectiveness of a mastery-oriented assessment, allowing both boys and girls to perform at an optimal level in a science class. Participants were 120 boys and 72 girls (all high-school students). Participants attended a science lesson while expecting a performance-oriented assessment (i.e., an assessment designed to compare and select students), a mastery-oriented assessment (i.e., an assessment designed to help students in their learning), or no assessment of this lesson. In the mastery-oriented assessment condition, both boys and girls performed at a similarly high level, whereas the performance-oriented assessment condition reduced girls' performance and the no-assessment condition reduced boys' performance. One way to increase girls' performance on a science test without harming boys' performance is to present assessment as a tool for improving mastery rather than as a tool for comparing performances. © 2013 The British Psychological Society.

Adaptive metal mirror for high-power CO2 lasers

Science.gov (United States)

Jarosch, Uwe-Klaus

1996-08-01

Spherical mirrors with a variable radius of curvature are used inside laser resonators as well as in the beam path between the laser and the workpiece. Commercially-available systems use piezoelectric actuators, or the pressure of the coolant, to deform the mirror surface. In both cases, the actuator and the cooling system influence each other. This interaction is avoided through the integration of the cooling system with the flexible mirror membrane. A multi- channel design leads to an optimized cooling effect, which is necessary for high power applications. The contour of the variable metal mirror depends on the mounting between the membrane and the mirror body and on the distribution of forces. Four cases of deformation can be distinguished for a circular elastic membrane. The realization of an adaptive metal mirror requires a technical compromise to be made. A mechanical construction is presented which combines an elastic hinge with the inlet and outlet of the coolant. For the deformation of the mirror membranes two actuators with different character of deformation are used. The superposition of the two deformations results in smaller deviations from the spherical surface shape than can be achieved using a single actuator. DC proportional magnets have been introduced as cheap and rigid actuators. The use of this adaptive mirror, either in a low pressure atmosphere of a gas laser resonator, or in an extra-cavity beam path is made possible through the use of a ventilation system.

Mirror neurons: Enigma of the metaphysical modular brain

OpenAIRE

Acharya, Sourya; Shukla, Samarth

2012-01-01

Mirror neurons are one of the most important discoveries in the last decade of neuroscience. These are a variety of visuospatial neurons which indicate fundamentally about human social interaction. Essentially, mirror neurons respond to actions that we observe in others. The interesting part is that mirror neurons fire in the same way when we actually recreate that action ourselves. Apart from imitation, they are responsible for myriad of other sophisticated human behavior and thought process...

In-situ shearing interferometry of National Synchrotron Light Source mirrors

International Nuclear Information System (INIS)

Qian, S.N.; Rarback, H.; Shu, D.; Takacs, P.Z.

1987-01-01

In situ mirror distortion measurements were made with a lateral shearing interferometer on three mirrors in beam line X17T at the National Syn203hrotron Light Source. Lateral shearing interference is insensitive to vibrational motion in five of the six degrees of freedom, so it is well-suited for investigations in the synchrotron radiation (SR) environment. No distortion was seen in an uncooled silicon carbide mirror and in a colled copper alloy mirror on X17TB, but a change in the radius of an uncooled electroless nickel-plated aluminium cylinder mirror of about 6.2% was observed on X17TA. Angular vibrations in the 2 to 3 arc second range were easily observed on one of the beam lines, as was an overall mirror rotation in the arc second range

Tandem mirror reactor

International Nuclear Information System (INIS)

Moir, R.W.; Barr, W.L.; Carlson, G.A.

1977-01-01

A parametric analysis and a preliminary conceptual design for a 1000 MWe Tandem Mirror Reactor (TMR) are described. The concept is sufficiently attractive to encourage further work, both for a pure fusion TMR and a low technology TMR Fusion-Fission Hybrid

Improved Mirror Source Method in Roomacoustics

Science.gov (United States)

Mechel, F. P.

2002-10-01

Most authors in room acoustics qualify the mirror source method (MS-method) as the only exact method to evaluate sound fields in auditoria. But evidently nobody applies it. The reason for this discrepancy is the abundantly high numbers of needed mirror sources which are reported in the literature, although such estimations of needed numbers of mirror sources mostly are used for the justification of more or less heuristic modifications of the MS-method. The present, intentionally tutorial article accentuates the analytical foundations of the MS-method whereby the number of needed mirror sources is reduced already. Further, the task of field evaluation in three-dimensional spaces is reduced to a sequence of tasks in two-dimensional room edges. This not only allows the use of easier geometrical computations in two dimensions, but also the sound field in corner areas can be represented by a single (directional) source sitting on the corner line, so that only this "corner source" must be mirror-reflected in the further process. This procedure gives a drastic reduction of the number of needed equivalent sources. Finally, the traditional MS-method is not applicable in rooms with convex corners (the angle between the corner flanks, measured on the room side, exceeds 180°). In such cases, the MS-method is combined below with the second principle of superposition(PSP). It reduces the scattering task at convex corners to two sub-tasks between one flank and the median plane of the room wedge, i.e., always in concave corner areas where the MS-method can be applied.

Quantum locking of mirrors in interferometers.

Science.gov (United States)

Courty, Jean-Michel; Heidmann, Antoine; Pinard, Michel

2003-02-28

We show that quantum noise in very sensitive interferometric measurements such as gravitational-wave detectors can be drastically modified by quantum feedback. We present a new scheme based on active control to lock the motion of a mirror to a reference mirror at the quantum level. This simple technique allows one to reduce quantum effects of radiation pressure and to greatly enhance the sensitivity of the detection.

Unbroken Mirror Neurons in Autism Spectrum Disorders

Science.gov (United States)

Fan, Yang-Teng; Decety, Jean; Yang, Chia-Yen; Liu, Ji-Lin; Cheng, Yawei

2010-01-01

Background: The "broken mirror" theory of autism, which proposes that a dysfunction of the human mirror neuron system (MNS) is responsible for the core social and cognitive deficits in individuals with autism spectrum disorders (ASD), has received considerable attention despite weak empirical evidence. Methods: In this electroencephalographic…

Thermal-mechanical behavior of high precision composite mirrors

Energy Technology Data Exchange (ETDEWEB)

Kuo, C.P.; Lou, M.C.; Rapp, D.

1993-01-01

Composite mirror panels were designed, constructed, analyzed, and tested in the framework of a NASA precision segmented reflector task. The deformations of the reflector surface during the exposure to space enviroments were predicted using a finite element model. The composite mirror panels have graphite-epoxy or graphite-cyanate facesheets, separated by an aluminum or a composite honeycomb core. It is pointed out that in order to carry out detailed modeling of composite mirrors with high accuracy, it is necessary to have temperature dependent properties of the materials involved and the type and magnitude of manufacturing errors and material nonuniformities. The structural modeling and analysis efforts addressed the impact of key design and materials parameters on the performance of mirrors. 4 refs.

Variable reflectivity signal mirrors and signal response measurements

International Nuclear Information System (INIS)

Vine, Glenn de; Shaddock, Daniel A; McClelland, David E

2002-01-01

Future gravitational wave detectors will include some form of signal mirror in order to alter the signal response of the device. We introduce interferometer configurations which utilize a variable reflectivity signal mirror allowing a tunable peak frequency and variable signal bandwidth. A detector configured with a Fabry-Perot cavity as the signal mirror is compared theoretically with one using a Michelson interferometer for a signal mirror. A system for the measurement of the interferometer signal responses is introduced. This technique is applied to a power-recycled Michelson interferometer with resonant sideband extraction. We present broadband measurements of the benchtop prototype's signal response for a range of signal cavity detunings. This technique is also applicable to most other gravitational wave detector configurations

Variable reflectivity signal mirrors and signal response measurements

CERN Document Server

Vine, G D; McClelland, D E

2002-01-01

Future gravitational wave detectors will include some form of signal mirror in order to alter the signal response of the device. We introduce interferometer configurations which utilize a variable reflectivity signal mirror allowing a tunable peak frequency and variable signal bandwidth. A detector configured with a Fabry-Perot cavity as the signal mirror is compared theoretically with one using a Michelson interferometer for a signal mirror. A system for the measurement of the interferometer signal responses is introduced. This technique is applied to a power-recycled Michelson interferometer with resonant sideband extraction. We present broadband measurements of the benchtop prototype's signal response for a range of signal cavity detunings. This technique is also applicable to most other gravitational wave detector configurations.

Electrostatic axisymmetric mirror with removable spherical aberration

International Nuclear Information System (INIS)

Birmuzaev, S.B.; Serikbaeva, G.S.; Hizirova, M.A.

1999-01-01

The electrostatic axisymmetric mirror, assembled from three coaxial cylinders with an equal diameter d and under the potential v1, v2 and v3, was computed. The proportions of geometrical and electric parameters of the mirror, with which the spherical 3-order aberration may be eliminated, were determined. The computation outcomes of the case, when the focal power of the mirror is enough large and the object plane in the focus is out of its field, are presented (Fig. 1 - potentials proportion that makes elimination of the spherical aberration possible; Fig. 2 - the focus coordinates when the spherical aberration is eliminated). The geometrical values are presented by d, and the electric ones are presented by v1. The figures on the curves present a length of the second (middle) electrode. The zero point is located in the middle of the gap between the first and second electrodes The investigated mirror may be used as a lens for the transmission electron microscope

Charge exchange cooling in the tandem mirror plasma confinement apparatus

Science.gov (United States)

Logan, B. Grant

1978-01-01

Method and apparatus for cooling a plasma of warm charged species confined in the center mirror cell of the tandem mirror apparatus by injecting cold neutral species of the plasma into at least one mirroring region of the center mirror cell, the cooling due to the loss of warm charged species through charge exchange with the cold neutral species with resulting diffusion of the warm neutral species out of the plasma.

Charge exchange cooling in the tandem mirror plasma confinement apparatus

International Nuclear Information System (INIS)

Logan, B.G.

1978-01-01

A method and apparatus are described for cooling a plasma confined in the center mirror cell of the tandem mirror apparatus by injecting cold neutral species of the plasma into at least one mirroring region of the center mirror cell. The cooling is due to the loss of warm charged species through charge exchange with the cold neutral species with resulting diffusion of the warm neutral species out of the plasma

Mirror Neurons, Embodied Cognitive Agents and Imitation Learning

OpenAIRE

Wiedermann, Jiří

2003-01-01

Mirror neurons are a relatively recent discovery; it has been conjectured that these neurons play an important role in imitation learning and other cognitive phenomena. We will study a possible place and role of mirror neurons in the neural architecture of embodied cognitive agents. We will formulate and investigate the hypothesis that mirror neurons serve as a mechanism which coordinates the multimodal (i.e., motor, perceptional and proprioceptive) information and completes it so that the ag...

Stability of the field-reversed mirror

International Nuclear Information System (INIS)

Morse, E.C.

1979-01-01

The stability of a field reversed mirror plasma configuration is studied with an energy principle derived from the Vlasov equation. Because of finite orbit effects, the stability properties of a field-reversed mirror are different from the stability properties of similar magnetohydrodynamic equilibria. The Vlasov energy principle developed here is applied to a computer simulation of an axisymmetric field-reversed mirror state. It has been possible to prove that the l = 0 modes, called tearing modes, satisfy a sufficient condition for stability. Precessional modes, with l = 1, 2, are found to be unstable at low growth rate. This suggests possible turbulent behavior (Bohm confinement) in the experimental devices aiming at field reversal. Techniques for suppressing these instabilities are outlined, and the applicability of the Vlasov energy principle to more complicated equilibrium models is shown

Bimorph mirrors: The Good, the Bad, and the Ugly

Science.gov (United States)

Alcock, Simon G.; Sutter, John P.; Sawhney, Kawal J. S.; Hall, David R.; McAuley, Katherine; Sorensen, Thomas

2013-05-01

Bimorph mirrors are widely used by the X-ray, Laser, Space, and Astronomy communities to focus or collimate photon beams. Applying voltages to the embedded piezo ceramics enables the user to globally bend the optical substrate to a range of figures (including cylindrical, parabolic, and elliptical), and finely correct low spatial frequency errors, thus improving optical performance. Bimorph mirrors are employed on numerous synchrotron X-ray beamlines, including several at Diamond Light Source. However, many such beamlines were not achieving the desired size and shape of the reflected X-ray beam. Metrology data from ex-situ, slope measuring profilometry (using the Diamond-NOM) and in-situ, synchrotron X-ray "pencil-beam" scans, revealed sharp defects on the optical substrate directly above the locations at which the piezo ceramics are bonded together. This so-called "junction effect" has been observed on a variety of bimorph mirrors with different numbers of piezos, substrate length, and thickness. To repair this damage, three pairs of bimorph mirrors were re-polished at Thales-SESO. We review the re-polishing process, and show that it successfully removed the junction effect, and significantly improved beamline performance. Since the internal structure of the bimorph mirrors was not modified during re-polishing, it is hoped that the mirrors will retain their surface quality, and remain operational for many years. We also highlight the combination of super-polishing techniques with bimorph technology to create the "Ultimate" mirror, and discuss a next generation, bimorph mirror which is predicted not to suffer from the junction effect.

Bimorph mirrors: The Good, the Bad, and the Ugly

International Nuclear Information System (INIS)

Alcock, Simon G.; Sutter, John P.; Sawhney, Kawal J.S.; Hall, David R.; McAuley, Katherine; Sorensen, Thomas

2013-01-01

Bimorph mirrors are widely used by the X-ray, Laser, Space, and Astronomy communities to focus or collimate photon beams. Applying voltages to the embedded piezo ceramics enables the user to globally bend the optical substrate to a range of figures (including cylindrical, parabolic, and elliptical), and finely correct low spatial frequency errors, thus improving optical performance. Bimorph mirrors are employed on numerous synchrotron X-ray beamlines, including several at Diamond Light Source. However, many such beamlines were not achieving the desired size and shape of the reflected X-ray beam. Metrology data from ex-situ, slope measuring profilometry (using the Diamond-NOM) and in-situ, synchrotron X-ray “pencil-beam” scans, revealed sharp defects on the optical substrate directly above the locations at which the piezo ceramics are bonded together. This so-called “junction effect” has been observed on a variety of bimorph mirrors with different numbers of piezos, substrate length, and thickness. To repair this damage, three pairs of bimorph mirrors were re-polished at Thales-SESO. We review the re-polishing process, and show that it successfully removed the junction effect, and significantly improved beamline performance. Since the internal structure of the bimorph mirrors was not modified during re-polishing, it is hoped that the mirrors will retain their surface quality, and remain operational for many years. We also highlight the combination of super-polishing techniques with bimorph technology to create the “Ultimate” mirror, and discuss a next generation, bimorph mirror which is predicted not to suffer from the junction effect

Robotic Mirror Therapy System for Functional Recovery of Hemiplegic Arms.

Science.gov (United States)

Beom, Jaewon; Koh, Sukgyu; Nam, Hyung Seok; Kim, Wonshik; Kim, Yoonjae; Seo, Han Gil; Oh, Byung-Mo; Chung, Sun Gun; Kim, Sungwan

2016-08-15

Mirror therapy has been performed as effective occupational therapy in a clinical setting for functional recovery of a hemiplegic arm after stroke. It is conducted by eliciting an illusion through use of a mirror as if the hemiplegic arm is moving in real-time while moving the healthy arm. It can facilitate brain neuroplasticity through activation of the sensorimotor cortex. However, conventional mirror therapy has a critical limitation in that the hemiplegic arm is not actually moving. Thus, we developed a real-time 2-axis mirror robot system as a simple add-on module for conventional mirror therapy using a closed feedback mechanism, which enables real-time movement of the hemiplegic arm. We used 3 Attitude and Heading Reference System sensors, 2 brushless DC motors for elbow and wrist joints, and exoskeletal frames. In a feasibility study on 6 healthy subjects, robotic mirror therapy was safe and feasible. We further selected tasks useful for activities of daily living training through feedback from rehabilitation doctors. A chronic stroke patient showed improvement in the Fugl-Meyer assessment scale and elbow flexor spasticity after a 2-week application of the mirror robot system. Robotic mirror therapy may enhance proprioceptive input to the sensory cortex, which is considered to be important in neuroplasticity and functional recovery of hemiplegic arms. The mirror robot system presented herein can be easily developed and utilized effectively to advance occupational therapy.

Journalism and science

DEFF Research Database (Denmark)

Meyer, Gitte

2006-01-01

that are likely to occur to journalistic attitudes - mirroring changing attitudes in the wider society - towards science and scientific researchers. Two journalistic conventions - those of science transmission and of investigative journalism - are presented and discussed in relation to the present drive towards...... commercialization within the world of science: how are journalists from these different schools of thought likely to respond to the trend of commercialization? Likely journalistic reactions could, while maintaining the authority of the scientific method, be expected to undermine public trust in scientists....... In the long term, this may lead to an erosion of the idea of knowledge as something that cannot simply be reduced o the outcome of negotiation between stakeholders. It is argued that science is likely to be depicted as a fallen angel. This may be countered, it is posited, by science turning human...

Mirror reactor blankets

International Nuclear Information System (INIS)

Lee, J.D.; Barmore, W.L.; Bender, D.J.; Doggett, J.N.; Galloway, T.R.

1976-01-01

The general requirements of a breeding blanket for a mirror reactor are described. The following areas are discussed: (1) facility layout and blanket maintenance, (2) heat transfer and thermal conversion system, (3) materials, (4) tritium containment and removal, and (5) nuclear performance

A Smart Home Center Platform Solution Based on Smart Mirror

Directory of Open Access Journals (Sweden)

Deng Xibo

2017-01-01

Full Text Available With the popularization of the concept of smart home, people have raised requirements on the experience of smart living. A smart home platform center solution is put forward in order to solve the intelligent interoperability and information integration of smart home, which enable people to have a more intelligent and convenient life experience. This platform center is achieved through the Smart Mirror. The Smart Mirror refers to a smart furniture, on the basis of the traditional concept of mirror, combining Raspberry Pi, the application of one-way mirror imaging principle, the touch－enabled design, voice and video interaction. Smart Mirror can provide a series of intelligent experience for the residents, such as controlling all the intelligent furniture through Smart Mirror; accessing and displaying the weather, time, news and other life information; monitoring the home environment; remote interconnection operation.

The Mirror in the Ground

DEFF Research Database (Denmark)

Shepherd, Nick

An important and original contribution to the study of the archive, The Mirror in the Ground approaches the discipline of archaeology in South Africa from the perspective of an interest in visualities. Author Nick Shepherd argues that it makes sense to talk about an archaeological aesthetics...... at the University of Cape Town, where he convenes a graduate programme on Public Culture and Heritage. The Mirror in the Ground is the first volume in the relaunched Series in Visual Histories, produced by the Centre for Curating the Archive (CCA) at the University of Cape Town....

Optical systems for synchrotron radiation. Lecture 2. Mirror systems

International Nuclear Information System (INIS)

Howells, M.R.

1986-02-01

The process of reflection of VUV and x-radiation is summarized. The functions of mirrors in synchrotron beamlines are described, which include deflection, filtration, power absorption, formation of a real image, focusing, and collimation. Fabrication of optical surfaces for synchrotron radiation beamlines are described, and include polishing of a near spherical surface as well as bending a cylindrical surface to toroidal shape. The imperfections present in mirrors, aberrations and surface figure inaccuracy, are discussed. Calculation of the thermal load of a mirror in a synchrotron radiation beam and the cooling of the mirror are covered briefly. 50 refs., 7 figs

Composite mirror facets for ground based gamma ray astronomy

Energy Technology Data Exchange (ETDEWEB)

Brun, P.; Carton, P.-H.; Durand, D.; Glicenstein, J.-F.; Jeanney, C. [CEA, Irfu, Centre de Saclay, F-91191 Gif sur Yvette (France); Medina, M.C., E-mail: clementina@iar.unlp.edu.ar [CEA, Irfu, Centre de Saclay, F-91191 Gif sur Yvette (France); Micolon, P.; Peyaud, B. [CEA, Irfu, Centre de Saclay, F-91191 Gif sur Yvette (France)

2013-06-21

Composite mirrors for gamma-ray astronomy have been developed to fulfill the specifications required for the next generation of Cherenkov telescopes represented by CTA (Cherenkov Telescope Array). In addition to the basic requirements on focus and reflection efficiency, the mirrors have to be stiff, lightweight, durable and cost efficient. In this paper, the technology developed to produce such mirrors is described, as well as some tests that have been performed to validate them. It is shown that these mirrors comply with the needs of CTA, making them good candidates for use on a significant part of the array.

Worthwhile optical method for free-form mirrors qualification

Science.gov (United States)

Sironi, G.; Canestrari, R.; Toso, G.; Pareschi, G.

2013-09-01

We present an optical method for free-form mirrors qualification developed by the Italian National Institute for Astrophysics (INAF) in the context of the ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) Project which includes, among its items, the design, development and installation of a dual-mirror telescope prototype for the Cherenkov Telescope Array (CTA) observatory. The primary mirror panels of the telescope prototype are free-form concave mirrors with few microns accuracy required on the shape error. The developed technique is based on the synergy between a Ronchi-like optical test performed on the reflecting surface and the image, obtained by means of the TraceIT ray-tracing proprietary code, a perfect optics should generate in the same configuration. This deflectometry test allows the reconstruction of the slope error map that the TraceIT code can process to evaluate the measured mirror optical performance at the telescope focus. The advantages of the proposed method is that it substitutes the use of 3D coordinates measuring machine reducing production time and costs and offering the possibility to evaluate on-site the mirror image quality at the focus. In this paper we report the measuring concept and compare the obtained results to the similar ones obtained processing the shape error acquired by means of a 3D coordinates measuring machine.

Motive of the Mirror in the Chechen Text

Directory of Open Access Journals (Sweden)

Alexandra V. Butenko

2017-03-01

Full Text Available The article discusses the concept of «Chechen text», which represents the local supratext, formed as a result of the literary and journalistic reflection events of the first and second Chechen campaign (1994-1996s, 1999-2009s. V.N.Toporov’s discovery of the Petersburg Text of Russian literature led to the idea of extrapolating of the supratext on other culturally significant loci. The article notes that the mythology and liminality are important features of the supratext, and its integrity forms common elements: the space-time organization, landscape description, through motives. One of these motives is the motive of the mirror, which functions in accordance with the tradition mythopoetic, indicating the border. Crossing through the mirror facet, due to the literary texts by G.Sadulaev, Z.Prilepin, A.Prokhanov symbolizes the immersion in a surreal hostile space, the space of war and violence. The image of a cloudy broken mirror, manifested in the story by P.Zherebtsova «Little angel», is interpreted as a sign of universal misery, destruction of the fundamental laws of life. The article deals with options such as complex semantic mirror, like a bridge, and glass. The implementation of the principle of the mirror vision (analogue mirror – dream may be the subject of a separate study.

Mirror Focus in a Patient with Intractable Occipital Lobe Epilepsy

OpenAIRE

Kim, Jiyoung; Shin, Hae kyung; Hwang, Kyoung Jin; Choi, Su Jung; Joo, Eun Yeon; Hong, Seung Bong; Hong, Seung Chul; Seo, Dae-Won

2014-01-01

Mirror focus is one of the evidence of progression in epilepsy, and also has practical points for curative resective epilepsy surgery. The mirror foci are related to the kindling phenomena that occur through interhemispheric callosal or commissural connections. A mirror focus means the secondary epileptogenic foci develop in the contralateral hemispheric homotopic area. Thus mirror foci are mostly reported in patients with temporal or frontal lobe epilepsy, but not in occipital lobe epilepsy....

Tandem mirror next step: remote maintenance

International Nuclear Information System (INIS)

Doggett, J.N.; Damm, C.C.; Hanson, C.L.

1980-01-01

This study of the next proposed experiment in the Mirror Fusion Program, the Tandem Mirror Next Step (TMNS), has included serious consideration of the maintenance requirements of such a large source of high energy neutrons with its attendant throughput of tritium. Although maintenance will be costly in time and money, our conclusion is that with careful attention to a design for maintenance plan such a device can be reliably operated

Effects of Self-Regulatory Strategy on Prospective Science Teachers' Chemistry Self Efficacy According to Class Level and Gender

Science.gov (United States)

Seyhan, Hatice Güngör

2016-01-01

This study aimed at determining the self-regulatory strategies and the chemistry self-efficacies of a total of one hundred and eighty-nine prospective science teachers in a state university in Turkey while studying the chemistry lesson according to the class level and gender factors. An additional goal was to examine the relationship level between…

Achromatic nested Kirkpatrick–Baez mirror optics for hard X-ray nanofocusing

International Nuclear Information System (INIS)

Liu, Wenjun; Ice, Gene E.; Assoufid, Lahsen; Liu, Chian; Shi, Bing; Khachatryan, Ruben; Qian, Jun; Zschack, Paul; Tischler, Jonathan Z.; Choi, J.-Y.

2011-01-01

A nested Kirkpatrick–Baez mirror pair has been designed, fabricated and tested for achromatic nanofocusing synchrotron hard X-rays. The prototype system achieved a FWHM focal spot of about 150 nm in both horizontal and vertical directions. The first test of nanoscale-focusing Kirkpatrick–Baez (KB) mirrors in the nested (or Montel) configuration used at a hard X-ray synchrotron beamline is reported. The two mirrors are both 40 mm long and coated with Pt to produce a focal length of 60 mm at 3 mrad incident angle, and collect up to a 120 µm by 120 µm incident X-ray beam with maximum angular acceptance of 2 mrad and a broad bandwidth of energies up to 30 keV. In an initial test a focal spot of about 150 nm in both horizontal and vertical directions was achieved with either polychromatic or monochromatic beam. The nested mirror geometry, with two mirrors mounted side-by-side and perpendicular to each other, is significantly more compact and provides higher demagnification than the traditional sequential KB mirror arrangement. Ultimately, nested mirrors can focus larger divergence to improve the diffraction limit of achromatic optics. A major challenge with the fabrication of the required mirrors is the need for near-perfect mirror surfaces near the edge of at least one of the mirrors. Special polishing procedures and surface profile coating were used to preserve the mirror surface quality at the reflecting edge. Further developments aimed at achieving diffraction-limited focusing below 50 nm are underway

Development of mirror coatings for gravitational-wave detectors

Science.gov (United States)

Steinlechner, J.

2018-05-01

Gravitational waves are detected by measuring length changes between mirrors in the arms of kilometre-long Michelson interferometers. Brownian thermal noise arising from thermal vibrations of the mirrors can limit the sensitivity to distance changes between the mirrors, and, therefore, the ability to measure gravitational-wave signals. Thermal noise arising from the highly reflective mirror coatings will limit the sensitivity both of current detectors (when they reach design performance) and of planned future detectors. Therefore, the development of coatings with low thermal noise, which at the same time meet strict optical requirements, is of great importance. This article gives an overview of the current status of coatings and of the different approaches for coating improvement. This article is part of a discussion meeting issue `The promises of gravitational-wave astronomy'.

Monitoring of absolute mirror alignment at COMPASS RICH-1 detector

NARCIS (Netherlands)

Alexeev, M.; Birsa, R.; Bradamante, F.; Bressan, A.; Chiosso, M.; Ciliberti, P.; Dalla Torre, S.; Denisov, O.; Duic, V.; Ferrero, A.; Finger, M.; Finger, M.; Gayde, J. Ch; Giorgi, M.; Gobbo, B.; Levorato, S.; Maggiora, A.; Martin, A.; Menon, G.; Panzieri, D.; Pesaro, G.; Polak, J.; Rocco, E.; Sbrizzai, G.; Schiavon, P.; Slunecka, M.; Sozzi, F.; Steiger, L.; Sulc, M.; Takekawa, S.; Tessarotto, F.

2014-01-01

The gaseous COMPASS RICH-1 detector uses two spherical mirror surfaces, segmented into 116 individual mirrors, to focus the Cherenkov photons onto the detector plane. Any mirror misalignment directly affects the detector resolution. The on-line Continuous Line Alignment and Monitoring (CLAM)

Integrated fiber-mirror ion trap for strong ion-cavity coupling

International Nuclear Information System (INIS)

Brandstätter, B.; Schüppert, K.; Casabone, B.; Friebe, K.; Stute, A.; Northup, T. E.; McClung, A.; Schmidt, P. O.; Deutsch, C.; Reichel, J.; Blatt, R.

2013-01-01

We present and characterize fiber mirrors and a miniaturized ion-trap design developed to integrate a fiber-based Fabry-Perot cavity (FFPC) with a linear Paul trap for use in cavity-QED experiments with trapped ions. Our fiber-mirror fabrication process not only enables the construction of FFPCs with small mode volumes, but also allows us to minimize the influence of the dielectric fiber mirrors on the trapped-ion pseudopotential. We discuss the effect of clipping losses for long FFPCs and the effect of angular and lateral displacements on the coupling efficiencies between cavity and fiber. Optical profilometry allows us to determine the radii of curvature and ellipticities of the fiber mirrors. From finesse measurements, we infer a single-atom cooperativity of up to 12 for FFPCs longer than 200 μm in length; comparison to cavities constructed with reference substrate mirrors produced in the same coating run indicates that our FFPCs have similar scattering losses. We characterize the birefringence of our fiber mirrors, finding that careful fiber-mirror selection enables us to construct FFPCs with degenerate polarization modes. As FFPCs are novel devices, we describe procedures developed for handling, aligning, and cleaning them. We discuss experiments to anneal fiber mirrors and explore the influence of the atmosphere under which annealing occurs on coating losses, finding that annealing under vacuum increases the losses for our reference substrate mirrors. X-ray photoelectron spectroscopy measurements indicate that these losses may be attributable to oxygen depletion in the mirror coating. Special design considerations enable us to introduce a FFPC into a trapped ion setup. Our unique linear Paul trap design provides clearance for such a cavity and is miniaturized to shield trapped ions from the dielectric fiber mirrors. We numerically calculate the trap potential in the absence of fibers. In the experiment additional electrodes can be used to compensate

Measurement and analysis of active synchrotron mirrors under operating conditions

Science.gov (United States)

Sutter, John P.; Alcock, Simon G.; Sawhney, Kawal

2013-05-01

At the Diamond Light Source, in situ slope error measurements using the pencil-beam method have enabled X-ray mirror surfaces to be examined in their beamline environment. A surface corrugation common to several bimorph mirrors and the removal of that corrugation by repolishing were both confirmed using this method. In the same way, mirrors curved in a controlled way with bending actuators and sag compensators could also be optimized. Fits to the elastic bending of ideal beams using the Euler-Bernoulli model have been performed on the slope errors of a mechanically bent mirror in order to distinguish bender curvatures from gravitational distortion and to calculate the compensating force that most reduces the latter effect. A successful improvement of the sag compensation mechanism of a vertically focusing mirror was also achieved, aided by a previously tested method for optimizing the settings of a mirror's actuators using pencil-beam scans.

Measurement and analysis of active synchrotron mirrors under operating conditions

International Nuclear Information System (INIS)

Sutter, John P.; Alcock, Simon G.; Sawhney, Kawal

2013-01-01

At the Diamond Light Source, in situ slope error measurements using the pencil-beam method have enabled X-ray mirror surfaces to be examined in their beamline environment. A surface corrugation common to several bimorph mirrors and the removal of that corrugation by repolishing were both confirmed using this method. In the same way, mirrors curved in a controlled way with bending actuators and sag compensators could also be optimized. Fits to the elastic bending of ideal beams using the Euler–Bernoulli model have been performed on the slope errors of a mechanically bent mirror in order to distinguish bender curvatures from gravitational distortion and to calculate the compensating force that most reduces the latter effect. A successful improvement of the sag compensation mechanism of a vertically focusing mirror was also achieved, aided by a previously tested method for optimizing the settings of a mirror's actuators using pencil-beam scans

Mirror mounts designed for the Advanced Photon Source SRI-CAT

International Nuclear Information System (INIS)

Shu, D.; Benson, C.; Chang, J.; Barraza, J.; Kuzay, T. M.; Alp, E. E.; Sturhahn, W.; Lai, B.; McNulty, I.; Randall, K.; Srajer, G.; Xu, Z.; Yun, W.

1997-01-01

Use of a mirror for beamlines at third-generation synchrotron radiation facilities, such as the Advanced Photon Source (APS) at Argonne National Laboratory, has many advantages. [Yun et al., Rev. Sci. Instrum. 67(9)(1996)CD-ROM] A mirror as a first optical component provides significant reduction in the beam peak heat flux and total power on the downstream monochromator and simplifies the bremsstrahlung shielding design for the beamline transport. It also allows us to have a system for multibeamline branching and switching. More generally, a mirror is used for beam focusing and/or low-pass filtering. Six different mirror mounts have been designed for the SRI-CAT beamlines. Four of them are designed as water-cooled mirrors for white or pink beam use, and the other two are for monochromatic beam use. Mirror mount designs, including vacuum vessel structure and precision supporting stages, are presented in this paper

Directional radiative cooling thermal compensation for gravitational wave interferometer mirrors

Energy Technology Data Exchange (ETDEWEB)

Justin Kamp, Carl [Department of Chemical Reaction Engineering, Chalmers University of Technology, SE-412 96 Goteborg (Sweden)], E-mail: carl.kamp@chalmers.se; Kawamura, Hinata [Yokoyama Junior High School, Sanda, Hachioji, Tokyo 193-0832 (Japan); Passaquieti, Roberto [Dipartimento di Fisica ' Enrico Fermi' and INFN Sezione di Pisa, Universita' di Pisa, Largo Bruno Pontecorvo, I-56127 Pisa (Italy); DeSalvo, Riccardo [LIGO Observatories, California Institute of Technology, Pasadena, CA 91125 (United States)

2009-08-21

The concept of utilizing directional radiative cooling to correct the problem of thermal lensing in the mirrors of the LIGO/VIRGO gravitational wave detectors has been shown and has prospects for future use. Two different designs utilizing this concept, referred to as the baffled and parabolic mirror solutions, have been proposed with different means of controlling the cooling power. The technique takes advantage of the power naturally radiated by the mirror surfaces at room temperature to prevent their heating by the powerful stored laser beams. The baffled solution has been simulated via COMSOL Multiphysics as a design tool. Finally, the parabolic mirror concept was experimentally validated with the results falling in close agreement with theoretical cooling calculations. The technique of directional radiative thermal correction can be reversed to image heat rings on the mirrors periphery to remotely and dynamically correct their radius of curvature without subjecting the mirror to relevant perturbations.

Beam line 4: A dedicated surface science facility at Daresbury Laboratory

International Nuclear Information System (INIS)

Dhanak, V.R.; Robinson, A.W.; van der Laan, G.; Thornton, G.

1992-01-01

We describe a beam line currently under construction at the Daresbury Laboratory which forms part of a surface science research facility for the Interdisciplinary Research Centre in Surface Science. The beam line has three branches, two of which are described here. The first branch covers the high-energy range 640 eV≤hν≤10 keV, being equipped with a double-crystal monochromator and a novel multicoated premirror system. The second branch line is optimized for the energy range 15≤hν≤250 eV, using cylindrical focusing mirrors, a spherical diffraction grating and an ellipsoidal refocusing mirror to achieve high resolution with a small spot size

The Quality of Instruction in Urban High Schools: Comparing Mathematics and Science to English and Social Studies Classes in Chicago

Science.gov (United States)

Lee, Valerie E.; Robinson, Shanta R.; Sebastian, James

2012-01-01

Is the quality of instruction systematically better in one subject than another? Teachers and students in the same Chicago high schools reported on one core-curriculum class (English, mathematics, science, or social studies) in 2007 surveys. Teachers commented on instructional demands and student participation. Students described engagement,…

Sensorimotor learning and the ontogeny of the mirror neuron system.

Science.gov (United States)

Catmur, Caroline

2013-04-12

Mirror neurons, which have now been found in the human and songbird as well as the macaque, respond to both the observation and the performance of the same action. It has been suggested that their matching response properties have evolved as an adaptation for action understanding; alternatively, these properties may arise through sensorimotor experience. Here I review mirror neuron response characteristics from the perspective of ontogeny; I discuss the limited evidence for mirror neurons in early development; and I describe the growing body of evidence suggesting that mirror neuron responses can be modified through experience, and that sensorimotor experience is the critical type of experience for producing mirror neuron responses. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Do 'literate' pigeons (Columba livia) show mirror-word generalization?

Science.gov (United States)

Scarf, Damian; Corballis, Michael C; Güntürkün, Onur; Colombo, Michael

2017-09-01

Many children pass through a mirror stage in reading, where they write individual letters or digits in mirror and find it difficult to correctly utilize letters that are mirror images of one another (e.g., b and d). This phenomenon is thought to reflect the fact that the brain does not naturally discriminate left from right. Indeed, it has been argued that reading acquisition involves the inhibition of this default process. In the current study, we tested the ability of literate pigeons, which had learned to discriminate between 30 and 62 words from 7832 nonwords, to discriminate between words and their mirror counterparts. Subjects were sensitive to the left-right orientation of the individual letters, but not the order of letters within a word. This finding may reflect the fact that, in the absence of human-unique top-down processes, the inhibition of mirror generalization may be limited.

Evolution of the mirror approach to fusion: some conjectures