Graphene and temperature controlled butterfly shape in permittivity-field loops of ferroelectric polymer nanocomposites

NASA Astrophysics Data System (ADS)

Adohi, B. J. P.; Brosseau, C.; Laur, V.; Haidar, B.

2017-01-01

We report on the field-dependent polarization of graphene (GE) filled poly[vinylidene fluoride-co-trifluoroethylene] P(VDF-TrFE) nanostructures fabricated by mechanical melt mixing. This study shows an increase in effective permittivity of these nanomaterials on increasing the GE loading in a manner that is consistent with standard mixing law. Detailed characterization of the unsaturated ferroelectric hysteresis, as well as the butterfly shape of the effective permittivity versus electric bias, of the samples are presented. For GE content set to 9.1 wt. % in the samples containing 50/50 wt. % (VDF/TrFE), the maximum polarization increases by 260% with respect to that of the neat polymer matrix. With a higher VDF content, 73 wt. %, the coercive field remains constant over the range of GE content explored. Additionally, our results highlight the strong impact of the GE loading and temperature on the butterfly shape in permittivity-field loops of these nanocomposites. The experimental findings are consistent with theoretical predictions of the modified Johnson's model [Narayanan et al., Appl. Phys. Lett. 100, 022907 (2012)]. Our findings can open avenues for interplay between conductive nanofillers and ferroelectricity in soft nanomaterials with controlled phase transitions.

Probing the biocompatibility of MoS2 nanosheets by cytotoxicity assay and electrical impedance spectroscopy

NASA Astrophysics Data System (ADS)

Shah, Pratikkumar; Narayanan, Tharangattu N.; Li, Chen-Zhong; Alwarappan, Subbiah

2015-08-01

Transition metal dichalgogenides such as MoS2 have recently emerged as hot two-dimensional (2D) materials due to their superior electronic and catalytic properties. Recently, we have reported the usefulness of MoS2 nanosheets toward the electrochemical detection of neurotransmitters and glucose (Narayanan et al 2014 Nanotechnology 25 335702). Furthermore, there are reports available in the literature that demonstrate the usefulness of MoS2 nanosheets for biosensing and energy storage applications (Zhu et al 2013 J. Am. Chem. Soc. 135 5998-6001 Pumera and Loo 2014 Trends Anal. Chem. 61 49-53 Lee et al 2014 Sci. Rep. 4 7352; Stephenson et al 2014 Energy Environ. Sci. 7 209-31). Understanding the cytotoxic effect of any material is very important prior to employing them for any in vivo biological applications such as implantable sensors, chips, or carriers for drug delivery and cell imaging purposes. Herein, we report the cytotoxicity of the MoS2 nanosheets based on the cytotoxic assay results and electrical impedance analysis using rat pheochromocytoma cells (PC12) and rat adrenal medulla endothelial cells (RAMEC). Our results indicated that the MoS2 nanosheets synthesized in our work are safe 2D nanosheets for futuristic biomedical applications.

Imaging for understanding speech communication: Advances and challenges

NASA Astrophysics Data System (ADS)

Narayanan, Shrikanth

2005-04-01

Research in speech communication has relied on a variety of instrumentation methods to illuminate details of speech production and perception. One longstanding challenge has been the ability to examine real-time changes in the shaping of the vocal tract; a goal that has been furthered by imaging techniques such as ultrasound, movement tracking, and magnetic resonance imaging. The spatial and temporal resolution afforded by these techniques, however, has limited the scope of the investigations that could be carried out. In this talk, we focus on some recent advances in magnetic resonance imaging that allow us to perform near real-time investigations on the dynamics of vocal tract shaping during speech. Examples include Demolin et al. (2000) (4-5 images/second, ultra-fast turbo spin echo) and Mady et al. (2001,2002) (8 images/second, T1 fast gradient echo). A recent study by Narayanan et al. (2004) that used a spiral readout scheme to accelerate image acquisition has allowed for image reconstruction rates of 24 images/second. While these developments offer exciting prospects, a number of challenges lie ahead, including: (1) improving image acquisition protocols, hardware for enhancing signal-to-noise ratio, and optimizing spatial sampling; (2) acquiring quality synchronized audio; and (3) analyzing and modeling image data including cross-modality registration. [Work supported by NIH and NSF.

Designing Writing Exercises to Emphasize Environmental Education

NASA Astrophysics Data System (ADS)

Narayanan, M.

2008-12-01

in a learning environment that enables them to acquire real-world problem-solving skills (Saxe, 1988; Senge, 1990; Sims, 1995). Educators should not allow the students to wonder whether they have been learning anything that would actually serve them in the workplace, upon graduation. (Barr and Tagg, 1995). Howard Gardner's list of Eight Intelligences is given below. 1. Linguistic intelligence ("word smart") 2. Logical intelligence ("number smart") 3. Spatial intelligence ("picture smart") 4. Kinesthetic intelligence ("body smart") 5. Musical intelligence ("music smart") 6. Interpersonal intelligence ("people smart") 7. Intrapersonal intelligence ("self smart") 8. Naturalist intelligence ("nature smart") The author has tried to examine students' learning development, behavior and exploration using some of the above eight Intelligences. In this presentation, he provides data he has collected while teaching certain selected courses (Narayanan, 2007). References Gardner, Howard. Frames of Mind: The Theory of Multiple Intelligences. New York: Basic,1983 Gardner, Howard. Multiple Intelligences: The Theory in Practice. New York: Basic, 1993. Gardner, Howard. Intelligence Reframed: Multiple Intelligences for the 21st Century. New York: Basic, 2000. Barr, R. B., and Tagg, J. (1995, November/December). From teaching to learning: A new paradigm for undergraduate education. Change: The Magazine of Higher Education, 13-24. Narayanan, Mysore (2007). Assessment of Perceptual Modality Styles. Proceedings of ASEE 2007 Annual Conference, Honolulu, Hawaii.

Use of Complementary and Alternative Medicine Treatments by Patients with Obstructive Sleep Apnea Hypopnea Syndrome

PubMed Central

Sood, Amit; Narayanan, Sujata; Wahner-Roedler, Dietlind L.; Knudsen, Kayla; Sood, Richa; Loehrer, Laura L.; Hanson, Andrew C.; Kuzniar, Tomasz J.; Olson, Eric J.

2007-01-01

Study Objectives: To assess the proportion of patients with obstructive sleep apnea hypopnea syndrome (OSAHS) reporting previous or current use and interest in future use of complementary and alternative medicine (CAM) therapies. Design: Cross-sectional, point-of-care, anonymous survey. Setting: Sleep disorders center at a Midwest tertiary care center. Participants: Six hundred forty-six consecutive patients undergoing polysomnography. Measurements: The survey instrument comprised 45 items specifically related to CAM therapies, in addition to obtaining baseline data. Results: Response rate was 81% (522/646). A total of 406/522 (78%) patients were diagnosed with OSAHS. Mean age ± SD was 57 ± 14 years, and 267 participants (66%) were men. Overall, 237 (58%) participants reported ever using CAM. Ever and current CAM use specifically for improving sleep was reported by 20% and 7% of the participants, respectively. Twenty-six percent of participants reported ever using biologic products, and 52% reported ever using nonbiologic CAM treatments. A high proportion (58%) of the participants showed interest in future CAM use for improving sleep. Conclusion: A high proportion of patients with OSAHS report previous or current use, and interest in future use, of CAM treatments. This underscores the need to conduct further research in this field. Citation: Sood A; Narayanan S; Wahner-Roedler DL; Knudsen K; Sood R; Loehrer LL; Hanson AC; Kuzniar TJ; Olson EJ. Use of complementary and alternative medicine treatments by patients with obstructive sleep apnea hypopnea syndrome. J Clin Sleep Med 2007;3(6):575-579. PMID:17993037

Aligning incentives in supply chains.

PubMed

Narayanan, V G; Raman, Ananth

2004-11-01

Most companies don't worry about the behavior of their supply chain partners. Instead, they expect the supply chain to work efficiently without interference, as if guided by Adam Smith's famed invisible hand. In their study of more than 50 supply networks, V.G. Narayanan and Ananth Raman found that companies often looked out for their own interests and ignored those of their network partners. Consequently, supply chains performed poorly. Those results aren't shocking when you consider that supply chains extend across several functions and many companies, each with its own priorities and goals. Yet all those functions and firms must pull in the same direction for a chain to deliver goods and services to consumers quickly and cost-effectively. According to the authors, a supply chain works well only if the risks, costs, and rewards of doing business are distributed fairly across the network. In fact, misaligned incentives are often the cause of excess inventory, stock-outs, incorrect forecasts, inadequate sales efforts, and even poor customer service. The fates of all supply chain partners are interlinked: If the firms work together to serve consumers, they will all win. However, they can do that only if incentives are aligned. Companies must acknowledge that the problem of incentive misalignment exists and then determine its root cause and align or redesign incentives. They can improve alignment by, for instance, adopting revenue-sharing contracts, using technology to track previously hidden information, or working with intermediaries to build trust among network partners. It's also important to periodically reassess incentives, because even top-performing networks find that changes in technology or business conditions alter the alignment of incentives.

PROCEEDINGS OF RIKEN BNL RESEARCH CENTER WORKSHOP ENTITLED - DOMAIN WALL FERMIONS AT TEN YEARS (VOLUME 84)

DOE Office of Scientific and Technical Information (OSTI.GOV)

BLUM,T.; SONI,A.

The workshop was held to mark the 10th anniversary of the first numerical simulations of QCD using domain wall fermions initiated at BNL. It is very gratifying that in the intervening decade widespread use of domain wall and overlap fermions is being made. It therefore seemed appropriate at this stage for some ''communal introspection'' of the progress that has been made, hurdles that need to be overcome, and physics that can and should be done with chiral fermions. The meeting was very well attended, drawing about 60 registered participants primarily from Europe, Japan and the US. It was quite remarkablemore » that pioneers David Kaplan, Herbert Neuberger, Rajamani Narayanan, Yigal Shamir, Sinya Aoki, and Pavlos Vranas all attended the workshop. Comparisons between domain wall and overlap formulations, with their respective advantages and limitations, were discussed at length, and a broad physics program including pion and kaon physics, the epsilon regime, nucleon structure, and topology, among others, emerged. New machines and improved algorithms have played a key role in realizing realistic dynamical fermion lattice simulations (small quark mass, large volume, and so on), so much in fact that measurements are now as costly. Consequently, ways to make the measurements more efficient were also discussed. We were very pleased to see the keen and ever growing interest in chiral fermions in our community and the significant strides our colleagues have made in bringing chiral fermions to the fore of lattice QCD calculations. Their contributions made the workshop a success, and we thank them deeply for sharing their time and ideas. Finally, we must especially acknowledge Norman Christ and Bob Mawhinney for their early and continued collaboration without which the success of domain wall fermions would not have been possible.« less

Epoxyeicosatrienoic acids pretreatment improves amyloid β-induced mitochondrial dysfunction in cultured rat hippocampal astrocytes.

PubMed

Sarkar, Pallabi; Zaja, Ivan; Bienengraeber, Martin; Rarick, Kevin R; Terashvili, Maia; Canfield, Scott; Falck, John R; Harder, David R

2014-02-15

Amyloid-β (Aβ) has long been implicated as a causative protein in Alzheimer's disease. Cellular Aβ accumulation is toxic and causes mitochondrial dysfunction, which precedes clinical symptoms of Alzheimer's disease pathology. In the present study, we explored the possible use of epoxyeicosatrienoic acids (EETs), epoxide metabolites of arachidonic acid, as therapeutic target against Aβ-induced mitochondrial impairment using cultured neonatal hippocampal astrocytes. Inhibition of endogenous EET production by a selective epoxygenase inhibitor, MS-PPOH, caused a greater reduction in mitochondrial membrane potential in the presence of Aβ (1, 10 μM) exposure versus absence of Aβ. MS-PPOH preincubation also aggravated Aβ-induced mitochondrial fragmentation. Preincubation of the cells with either 14,15- or 11,12-EET prevented this mitochondrial depolarization and fragmentation. EET pretreatment also further improved the reduction observed in mitochondrial oxygen consumption in the presence of Aβ. Preincubation of the cells with EETs significantly improved cellular respiration under basal condition and in the presence of the protonophore, carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP). The uncoupling of ATP synthase from the electron transfer chain that occurred in Aβ-treated cells was also prevented by preincubation with EETs. Lastly, cellular reactive oxygen species production, a hallmark of Aβ toxicity, also showed significant reduction in the presence of EETs. We have previously shown that Aβ reduces EET synthesis in rat brain homogenates and cultured hippocampal astrocytes and neurons (Sarkar P, Narayanan J, Harder DR. Differential effect of amyloid beta on the cytochrome P450 epoxygenase activity in rat brain. Neuroscience 194: 241-249, 2011). We conclude that reduction of endogenous EETs may be one of the mechanisms through which Aβ inflicts toxicity and thus supplementing the cells with exogenous EETs improves mitochondrial dynamics and

Consequences of Not Conserving Water

NASA Astrophysics Data System (ADS)

Narayanan, M.; Crawford, L.

2015-12-01

The problem of fresh water is not only local, but also global. In certain parts of the world, much needed rain is becoming less frequent, possibly due to the effects of global warming. The resources of clean fresh water on earth are very limited and are reducing every year due to pollution like industrial waste, oil spills, untreated sewage, inefficient irrigation systems, waste and leakage, etc. This is destroying the ecosystem of the entire planet. Of course, in some parts of world there is rain almost throughout the year. Regardless, major problems are still prevalent because of a variety of reasons such as drainage, storage, evaporation, cleanliness, etc. It is all too well known that evapotranspiration contributes to a significant water loss from drainage basins. Most of the citizens of this world are still careless about water usage and are unappreciative of the need for water conservation. This is a very unpleasant fact and needs to change. Cost expenditures for the development of infrastructure to supply water to households and industries are becoming prohibitively expensive. Many parts in this world have extremely dry terrain and rainfall is not as frequent as it should be. As a result, the underground water tables are not replenished properly, thereby turning regions to arid land and deserts. Unless effective irrigation methods are used, potential evapotranspiration may be actually greater than precipitation provided by nature. The soil therefore dries out creating an arid landmass. The earth and its inhabitants can sustain only if creative methods of clean water conservation ideas are effectively implemented. (Co-author: Dr. Mysore Narayanan) References: http://www.epa.gov/oaintrnt/water/http://www.usda.gov/wps/portal/usda/usdahome?navid=conservationhttp://www.ecy.wa.gov/programs/wr/ws/wtrcnsv.htmlhttp://www.sandiego.gov/water/conservation/http://www.swcs.org/http://www.awwa.org/resources-tools/water-knowledge/water-conservation.aspxhttp://www.benefits-of-recycling.com/waterconservationmethods/

Is there a crisis in American Higher Education?

NASA Astrophysics Data System (ADS)

Narayanan, M.; Crawford, L.

2015-12-01

According to the Spellings Commission, the answer to the above question is yes. The commission declared that a crisis exists in American higher education. In their report published in 2005, they claim that colleges and universities are becoming less accessible and less accountable. They indicate that colleges and universities are failing to prepare the students to meet the demanding challenges of the present day workforce and are struggling to maintain an international status (Johnson, K. 2013). The Spellings Report called for information about the quality and cost of college degrees. Authors, Richard Arum and Josipa Roksa claim that American students are learning very little during their first two years of college. Higher education in the United States is examined by these two authors. Josipa Roksa is an Associate Professor of Sociology and Education at the University of Virginia. She is currently serving as Special Advisor to the Provost and Associate Director of the Center for Advanced Study of Teaching and Learning in Higher Education. Richard Arum is an American sociologist who is currently professor of sociology and education at New York University. Arum is also a senior fellow at the Bill and Melinda Gates Foundation. Their research draws on transcript data, the Collegiate Learning Assessment, and survey responses from more than 2,300 undergraduates at twenty-four institutions in their first semester and again at the end of their second year. The analysis reveals that 45 percent of these students demonstrated no significant improvement in a range of skills--including critical thinking, complex reasoning, and writing--during their first two years of college (Arum and Roksa, 2011). (Co-author: Dr. Mysore Narayanan) References: Johnson, Kristine (2013) "Why Students Don't Write: Educating in the Era of Credentialing: Academically Adrift: Limited Learning on College Campuses," Conversations on Jesuit Higher Education: Vol. 43, Article 9. Available at: http

A physical model for z ~ 2 dust-obscured galaxies

NASA Astrophysics Data System (ADS)

Narayanan, Desika; Dey, Arjun; Hayward, Christopher C.; Cox, Thomas J.; Bussmann, R. Shane; Brodwin, Mark; Jonsson, Patrik; Hopkins, Philip F.; Groves, Brent; Younger, Joshua D.; Hernquist, Lars

2010-09-01

We present a physical model for the origin of z ~ 2 dust-obscured galaxies (DOGs), a class of high-redshift ultraluminous infrared galaxies (ULIRGs) selected at 24μm which are particularly optically faint (F24μm/FR > 1000). By combining N-body/smoothed particle hydrodynamic simulations of high-redshift galaxy evolution with 3D polychromatic dust radiative transfer models, we find that luminous DOGs (with F24 >~ 0.3mJy at z ~ 2) are well modelled as extreme gas-rich mergers in massive (~5 × 1012-1013Msolar) haloes, with elevated star formation rates (SFR; ~500-1000Msolaryr-1) and/or significant active galactic nuclei (AGN) growth , whereas less luminous DOGs are more diverse in nature. At final coalescence, merger-driven DOGs transition from being starburst dominated to AGN dominated, evolving from a `bump' to a power-law (PL) shaped mid-IR (Infrared Array Camera, IRAC) spectral energy distribution (SED). After the DOG phase, the galaxy settles back to exhibiting a `bump' SED with bluer colours and lower SFRs. While canonically PL galaxies are associated with being AGN dominated, we find that the PL mid-IR SED can owe both to direct AGN contribution and to a heavily dust obscured stellar bump at times that the galaxy is starburst dominated. Thus, PL galaxies can be either starburst or AGN dominated. Less luminous DOGs can be well-represented either by mergers or by massive (Mbaryon ~ 5 × 1011Msolar) secularly evolving gas-rich disc galaxies (with SFR >~ 50Msolaryr-1). By utilizing similar models as those employed in the submillimetre galaxy (SMG) formation study of Narayanan et al., we investigate the connection between DOGs and SMGs. We find that the most heavily star-forming merger-driven DOGs can be selected as submillimetre galaxies, while both merger-driven and secularly evolving DOGs typically satisfy the BzK selection criteria. The model SEDs from the simulated galaxies match observed data reasonably well, though Mrk 231 and Arp 220 templates provide

Learn, how to learn

NASA Astrophysics Data System (ADS)

Narayanan, M.

2002-12-01

. Maintain Momentum. 13. Feedback : Communication. 14. Fact - Based Decisions. 15. Exploit Opportunities. 16. Mobilization of Expertise. 17. Drive out Fear. 18. Recognition / Keep Score. 19. Identify Accomplishments. 20. Customer Focus / Results. In conclusion, the author believes that the ACORN model and the QUOTES model may offer some guidelines that would help and enable the instructor to motivate learners to learn on their own. References Boyer, Ernest L. (1990). Scholarship reconsidered: Priorities of the Professorate. Princeton, NJ: Carnegie Foundation for the Advancement of Teaching. Hawkins, P., and Winter, J. (1997). Mastering change: Learning the lessons of the enterprise in higher education initiative. London: Department for Education and Employment. Narayanan, Mysore (2002). Total Quality Management (TQM) and the Teaching Professor. Oxford, Ohio. : Mimi University : 22nd Annual Lilly Conference on College Teaching.

Importance of Technical Writing in Engineering Education

NASA Astrophysics Data System (ADS)

Narayanan, M.

2010-12-01

., Grasha, A., & Richlin, L. (1997, March). Town meeting. Between teaching model and learning model: Adapting and adopting bit by bit. Paper presented at the ninth annual Lilly Conference on College and University Teaching - West, Lake Arrowhead, CA. Narayanan, Mysore (2009). Assessment Based on the principles of Theodore Marchese. ASEE 116th Annual Conference and Exposition, Austin, TX. June 14-17, 2009. Paper # AC 2009-1532. Saxe, S. (1990, June). Peer influence and learning. Training and Development Journal, 42 (6), 50-53. Senge, P. M. (1990). The fifth discipline: The art and practice of the learning organization. New York: Currency Doubleday. Sims, R. R. (1992, Fall). Developing the learning climate in public sector training programs. Public Personnel Management, 21 (3), 335-346. Kosakowski, John, (1998). The Benefits of Information Technology. ERIC Digests; Technology Integration; Technology Role, ED0-IR-98-04 Chaika, Gloria (2000), Encourage Student Writing: Published on the Web, Education World http://www.education-world.com/a_tech/tech042.shtml

Writers, Athletes and Engineers Learn by Doing

NASA Astrophysics Data System (ADS)

Narayanan, M.

2009-12-01

provided evidence-based reasoning and critical thinking. 6. He/She has suggested a time-line for completing the assignment. 7. The person has completed the required process in the alloted time-line. In this presentation the author stresses the importance of writing assignments in engineering disciplines. References: Barr, R. B., & Tagg, J. (1995, November/December). From teaching to learning: A new paradigm for undergraduate education. Change: The Magazine of Higher Education, 13-24. Cox, M. D., Grasha, A., & Richlin, L. (1997, March). Town meeting. Between teaching model and learning model: Adapting and adopting bit by bit. Paper presented at the ninth annual Lilly Conference on College and University Teaching - West, Lake Arrowhead, CA. Narayanan, Mysore (2009). Assessment Based on the principles of Theodore Marchese. ASEE 116th Annual Conference and Exposition, Austin, TX. June 14-17, 2009. Paper # AC 2009-1532. Saxe, S. (1990, June). Peer influence and learning. Training and Development Journal, 42 (6), 50-53. Senge, P. M. (1990). The fifth discipline: The art and practice of the learning organization. New York: Currency Doubleday.

The Importance of Water Conservation in the 21st Century

NASA Astrophysics Data System (ADS)

Narayanan, M.

2012-12-01

Performance Plan. The report details key priorities for the Agency: 1. GHG emissions inventories and reduction through energy efficiency, renewable energy, and transportation management. 2. High-performance sustainable buildings. 3. Regional and local planning. 4. Water conservation. 5. Recycling and pollution prevention. 6. Sustainable acquisition. 7. Electronics stewardship. Many researchers are of the opinion that applying the principles of free market enterprise to water conservation ideas would result in a more efficient utilization of water supply and distribution everywhere. References: EPA's June 2011 Strategic Sustainability Performance Plan (SSPP) (PDF) (74 pp, 1MB) June 2010 EPA Strategic Sustainability Performance Plan (PDF) (67 pp, 3.8MB) U.S. EPA Policy Statement on Climate-Change Adaptation (PDF) (3pp, 55KB) Narayanan, Mysore. (2008). Hydrology, Water Scarcity and Market Economics. 68th AGU International Conference. Eos Transactions: American Geophysical Union, Vol. 89, No. 53, Fall Meeting Supplement, 2009. H11E - 0801. Postel, Sandra L. The Last Oasis: Facing Water Scarcity. New York: W. W. Norton and Company. 1997.

21st Century Water Conservation Principles

NASA Astrophysics Data System (ADS)

Narayanan, M.

2013-12-01

report details key priorities for the Agency: Many researchers are of the opinion that applying the principles of free market enterprise to water conservation ideas would result in a more efficient utilization of water supply and distribution everywhere. References: EPA's June 2011 Strategic Sustainability Performance Plan (SSPP) (PDF) (74 pp, 1MB) June 2010 EPA Strategic Sustainability Performance Plan (PDF) (67 pp, 3.8MB) U.S. EPA Policy Statement on Climate-Change Adaptation (PDF) (3pp, 55KB) Narayanan, Mysore. (2008). Hydrology, Water Scarcity and Market Economics. 68th AGU International Conference. Eos Transactions: American Geophysical Union, Vol. 89, No. 53, Fall Meeting Supplement, 2009. H11E - 0801. Postel, Sandra L. The Last Oasis: Facing Water Scarcity. New York: W. W. Norton and Company. 1997. Falkenmark, M.J. and Rockström, J. (2004). Balancing Water For Humans and Nature. Sterling, VA. Earthscan. Giordano, M. (2006) Agricultural Groundwater Use and Rural Livelihoods Journal of Hydrogeology. 14, 310 - 318. Allan, J.A. (2003). Virtual Water. Useful Concept or Misleading Metaphor? Water International. 28, 4-11. Vörsömarty, C.J., Douglas, E.M., Green, P.A. and Revenga, C. 2005. Geospatial Indicators of Energing Water Stress. Ambio, 34. 230-236.

Classroom Assessment Techniques

NASA Astrophysics Data System (ADS)

Narayanan, M.

2003-12-01

and the learner should be carefully observed and monitored. Forrest says that Student Portfolios, which document learning in more detail, seldom reveal how teaching contributes to students' progress. Cerbin further indicates that a course portfolio is essentially, a like a manuscript of scholarly work in progress. In this example, it is a work that explains what, how, and why students learn or do not learn in a course. In this paper, the author reports on a dozen techniques that could perhaps be used to document assessment of student learning. References : Cerbin, W. (1993). Fostering a culture of teaching as scholarship. The Teaching Professor, 7(3), 1-2. Edgerton, R., Hutchings, P., & Quinlan, P. (1991). The teaching portfolio: Capturing the scholarship in teaching. Washington, DC: American Association for Higher Education. Forrest, A. (1990). Time will tell: Portfolio-assisted assessment of general education. Washington, DC: American Association for Higher Education. Linn, R., Baker, E., & Dunbar, S. (1991). Complex, Performance-based Assessment: Expectations and Validation Criteria. Educational Researcher, 20 (8), 15-21. Narayanan, M. (2003). Assessment in Higher Education: Partnerships in Learning. Paper presented at the 23rd Annual Lilly Conference on College Teaching, Miami University, Oxford, OH. Seldin, P. (1991). The teaching portfolio. Bolton, MA: Anker. Young, C. O., Sr., & Young, L. H. (1999). Assessing Learning in Interactive Courses. Journal on Excellence in College Teaching, 10 (1), 63-76.

Singular value decomposition utilizing parallel algorithms on graphical processors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kotas, Charlotte W; Barhen, Jacob

2011-01-01

transformations, and then diagonalizes the intermediate bidiagonal matrix through implicit QR shifts. This is similar to that implemented for real matrices by Lahabar and Narayanan ("Singular Value Decomposition on GPU using CUDA", IEEE International Parallel Distributed Processing Symposium 2009). The implementation is done in a hybrid manner, with the bidiagonalization stage done using the GPU while the diagonalization stage is done using the CPU, with the GPU used to update the U and V matrices. The second algorithm is based on a one-sided Jacobi scheme utilizing a sequence of pair-wise column orthogonalizations such that A is replaced by AV until the resulting matrix is sufficiently orthogonal (that is, equal to U ). V is obtained from the sequence of orthogonalizations, while can be found from the square root of the diagonal elements of AH A and, once is known, U can be found from column scaling the resulting matrix. These implementations utilize CUDA Fortran and NVIDIA's CUB LAS library. The primary goal of this study is to quantify the comparative performance of these two techniques against themselves and other standard implementations (for example, MATLAB). Considering that there is significant overhead associated with transferring data to the GPU and with synchronization between the GPU and the host CPU, it is also important to understand when it is worthwhile to use the GPU in terms of the matrix size and number of concurrent SVDs to be calculated.« less

PREFACE: Cell-substrate interactions Cell-substrate interactions

NASA Astrophysics Data System (ADS)

Gardel, Margaret; Schwarz, Ulrich

2010-05-01

system, is strongly modulated by mechanosensing on substrates of varying stiffness [21]. Mogilner and Rubinstein present a theoretical systems analysis for the shape of rapidly migrating keratocytes [22]. Saez et al show, with microfabricated pillar assays, how force is distributed within a layer of epithelial cells [23]. For three-dimensional tissue models, new techniques have to be developed to characterize the complex mechanics of hydrogels. Levental et al [24] and Kotlarchyk et al [25] approach this challenge with mechanical and optical methods, respectively. Narayanan et al combine experiments and continuum models to explore how chemo-mechanical interactions influence tumor growth [26]. References [1] Chen C S, Mrksich M, Huang S, Whitesides G M and Ingber D E 1997 Geometric control of cell life and death Science 276 1425 [2] Pelham R J Jr and Wang Y-L 1997 Cell locomotion and focal adhesions are regulated by substrate flexibility Proc. Natl. Acad. Sci. USA 94 13661 [3] Engler A J, Sen S, Sweeney H L and Discher D E 2006 Matrix elasticity directs stem cell lineage specification Cell 126 677-89 [4] Geiger B, Spatz J P and Bershadsky A D 2009 Environmental sensing through focal adhesions Nat. Rev. Mol. Cell Biol. 10 21 [5] Boettiger D and Wehrle-Haller B 2010 Integrin and glycocalyx mediated contributions to cell adhesion identified by single cell force spectroscopy J. Phys.: Condens. Matter 22 194101 [6] Chirasatitsin S and Engler A J 2010 Detecting cell-adhesive sites in extracellular matrix using force spectroscopy mapping J. Phys.: Condens. Matter 22 194102 [7] Scrimgeour J, Kodali V K, Kovari D T and Curtis J E 2010 Photobleaching-activated micropatterning on self-assembled monolayers J. Phys.: Condens. Matter 22 194103 [8] Stricker J, Sabass B, Schwarz U S and Gardel M L 2010 Optimization of traction force microscopy for micron-sized focal adhesions J. Phys.: Condens. Matter 22 194104 [9] Metzner C, Raupach C, Mierke C T and Fabry B 2010 Fluctuations of

EDITORIAL: Strongly correlated electron systems Strongly correlated electron systems

NASA Astrophysics Data System (ADS)

Ronning, Filip; Batista, Cristian

2011-03-01

-dependent Zeeman splitting in strontium ruthenate Emil J Rozbicki, James F Annett, Jean-René Souquet and Andrew P Mackenzie Thermodynamics of itinerant metamagnetic transitions A M Berridge Magnon-mediated pairing and isotope effect in iron-based superconductors Jiansheng Wu and Philip Phillips Nernst quantum oscillations in bulk semi-metals Zengwei Zhu, Huan Yang, Aritra Banerjee, Liam Malone, Benoît Fauqué and Kamran Behnia Signatures of a quantum Griffiths phase in a d-metal alloy close to its ferromagnetic quantum critical point Almut Schroeder, Sara Ubaid-Kassis and Thomas Vojta Influence of super-ohmic dissipation on a disordered quantum critical point Thomas Vojta, José A Hoyos, Priyanka Mohan and Rajesh Narayanan The van Hemmen-Kondo model for disordered cerium systems S G Magalhaes, F M Zimmer and B Coqblin Chemical pressure, dilution and disorder in the heavy fermion compounds Ce3 - xLaxPd20Si6 (x = 1/3, 2/3) H Winkler, K-A Lorenzer, S Laumann, J Custers, A Prokofiev and S Paschen Magnetism of fine particles of Kondo lattices, obtained by high-energy ball-milling E V Sampathkumaran, K Mukherjee, Kartik K Iyer, Niharika Mohapatra and Sitikantha D Das Heavy fermion scaling: uranium versus cerium and ytterbium compounds J M Lawrence, C H Wang, A D Christianson and E D Bauer Temperature dependence of hybridization gaps in metallic heavy-fermion systems Xiaodong Yang, Peter S Riseborough and Tomasz Durakiewicz Low-energy properties of the Kondo lattice model O Bodensiek, R Žitko, R Peters and T Pruschke Temperature dependence of the zero-bias anomaly in the Anderson-Hubbard model: insights from an ensemble of two-site systems R Wortis and W A Atkinson A charge density wave in the hidden order state of URu2Si2 Jung-Jung Su, Yonatan Dubi, Peter Wölfle and Alexander V Balatsky Field-induced suppression of the heavy-fermion state in YbRh2Si2 Gertrud Zwicknagl Discontinuous Hall coefficient at the quantum critical point in YbRh2Si2 Sven Friedemann, Niels Oeschler, Steffen

EDITORIAL: Colloidal suspensions Colloidal suspensions

NASA Astrophysics Data System (ADS)

Petukhov, Andrei; Kegel, Willem; van Duijneveldt, Jeroen

2011-05-01

Colloid-polymer mixtures and depletion interactions Phase stability of a reversible supramolecular polymer solution mixed with nanospheres Remco Tuinier When depletion goes critical Roberto Piazza, Stefano Buzzaccaro, Alberto Parola and Jader Colombo Tuning the demixing of colloid-polymer systems through the dispersing solvent E A G Jamie, R P A Dullens and D G A L Aarts Polydispersity effects in colloid-polymer mixtures S M Liddle, T Narayanan and W C K Poon Colloidal dynamics and crystallization Crystallization and aging in hard-sphere glasses C Valeriani, E Sanz, E Zaccarelli, W C K Poon, M E Cates and P N Pusey Real-time monitoring of complex moduli from micro-rheology Taiki Yanagishima, Daan Frenkel, Jurij Kotar and Erika Eiser Brownian motion of a self-propelled particle B ten Hagen, S van Teeffelen and H Löwen Crystallization in suspensions of hard spheres: a Monte Carlo and molecular dynamics simulation study T Schilling, S Dorosz, H J Schöpe and G Opletal Structural signature of slow dynamics and dynamic heterogeneity in two-dimensional colloidal liquids: glassy structural order Takeshi Kawasaki and Hajime Tanaka