Introduction to the Mymaridae (Hymenoptera) of Bangladesh.

PubMed

Huber, John T; Islam, Nurul

2017-01-01

An identification key to the 15 genera of Mymaridae found so far in Bangladesh is given, based on about 520 specimens collected using yellow pan traps placed in agricultural habitats and at the edge of ponds, mainly at Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur. Species already reported from Bangladesh are listed and three more are added: Acmopolynema orientale (Narayanan, Subba Rao & Kaur), Himopolynema hishimonus Taguchi, and Mymar pulchellum Curtis.

KSC-04pd1108

NASA Image and Video Library

2004-05-05

KENNEDY SPACE CENTER, FLA. -- A film crew from India sets up equipment inside the television studio at the NASA News Center. The crew spent several days at KSC filming at various sites for the movie “Swades,” a story about India’s brain-drain. At center is Mahesh Aney, director of photography. The writer and director is Ashutosh Gowariker (seen to the right of Aney). The lead actors are Shahrukh Khan and Gayatri Joshi. Sunita Gowariker is executive producer.

Is Storage a Solution to End Water Shortage?

NASA Astrophysics Data System (ADS)

Narayanan, M.

2009-12-01

Water shortage is a problem of supply and demand. Some authors refer to it as Water Scarcity. The author has discussed this in his previous presentation at the 2008 AGU International Conference. Part of it is reproduced here for purposes of clarification. It is important to recognize that water is essential for the survival of all life on earth. Many water-rich states have thought of water conservation as an art that is practiced mainly in the arid states. But one has to recite the famous quote: “You will never miss water till the well runs dry.” Researchers have also concluded that quantity deficiency experienced by groundwater supplies are affecting many communities around the world. Furthermore federal regulations pertaining to the quality of potable or drinking water have become more stringent (Narayanan, 2008). One must observe that water conservation schemes and efficient utilization practices also benefit the environment to a large extent. These water conservation practicies indeed have a short payback period althought it may seem that there is a heavy initial investment is required. Research scientists have studied MARR (Mean Annual River Runoff) pattern over the years and have arrived at some significant conclusions. Vörsömarty and other scientists have indicated that water scarcity exists when the demand to supply ratio exceeds the number 0.4. (Vörsömarty, 2005). Furthermore other researchers claim to have documented a six-fold increase in water use in the United States during the last century. It is interesting to note that the population of the United States has hardly doubled during the last century. This obviously, is indicative of higher living standards. Nevertheless, it also emphasizes an urgent need for establishing a strong, sound, sensible and sustainable management program for utilizing the available water supplies efficiently (Narayanan, 2008). Author of the 1998 book, Last Oasis: Facing Water Scarcity, Dr. Sandra Postel predicts big water availability problems as populations of so-called “water-stressed” countries jump perhaps six fold over the next 30 years (Narayanan, 2008). It is also recognized that almost three-quarters of the globe is covered with water. Regardless, this is salt-water and there is very limited supply of freshwater to meet the needs of exploding global population. References: 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.

Localization under Adversary Misdirection

DTIC Science & Technology

2014-10-01

0.5 1 −1 −0.5 0 0.5 1 x [meters] y [m et er s ] (a) eadv = [0 0.05] (b) eadv= [0 0.36] ( c ) eadv = [0 1] Figure 18: Maximum distance...2009. [47] C . Meesookho, U. Mitra, and S . Narayanan. On energy-based acoustic source localization for sensor networks. IEEE Transactions on Signal...Processing, 56(1):365–377, 2008. [48] C . Meng, Z. Ding, and S . Dasgupta. A semidefinite programming approach to source localization in wireless sensor

Software For Fault-Tree Diagnosis Of A System

NASA Technical Reports Server (NTRS)

Iverson, Dave; Patterson-Hine, Ann; Liao, Jack

1993-01-01

Fault Tree Diagnosis System (FTDS) computer program is automated-diagnostic-system program identifying likely causes of specified failure on basis of information represented in system-reliability mathematical models known as fault trees. Is modified implementation of failure-cause-identification phase of Narayanan's and Viswanadham's methodology for acquisition of knowledge and reasoning in analyzing failures of systems. Knowledge base of if/then rules replaced with object-oriented fault-tree representation. Enhancement yields more-efficient identification of causes of failures and enables dynamic updating of knowledge base. Written in C language, C++, and Common LISP.

Water Conservation and Water Storage

NASA Astrophysics Data System (ADS)

Narayanan, M.

2014-12-01

Water storage can be a viable part of the solution to water conservation. This means that we should include reservoirs. Regardless, one should evaluate all aspects of water conservation principles. Recent drought in California indicates that there is an urgent need to re-visit the techniques used to maintain the water supply-chain mechanism in the entire state. We all recognize the fact that fish and wildlife depend on the streams, rivers and wetlands for survival. It is a well-known fact that there is an immediate need to provide solid protection to all these resources. Laws and regulations should help meet the needs of natural systems. Farmers may be forced to drilling wells deeper than ever. But, they will be eventually depleting groundwater reserves. Needless to say that birds, fish and wildlife cannot access these groundwater table. California is talking a lot about conservation. Unfortunately, the conservation efforts have not established a strong visible hold. The Environmental Protection Agency has a plan called E2PLAN (Narayanan, 2012). It is EPA's plan for achieving energy and environmental performance, leadership, accountability, and carbon neutrality. In June 2011, the EPA published a comprehensive, multi-year planning document called Strategic Sustainability Performance Plan. The author has previously reported these in detail at the 2012 AGU fall meeting. References: Ziegler, Jay (15 JUNE 2014). The Conversation: Water conservation efforts aren't taking hold, but there are encouraging signs. THE SACRAMENTO BEE. California. Narayanan, Mysore. (2012). The Importance of Water Conservation in the 21st Century. 72nd AGU International Conference. Eos Transactions: American Geophysical Union, Vol. 92, No. 56, Fall Meeting Supplement, 2012. H31I - 1255.http://www.sacbee.com/2014/06/15/6479862/jay-ziegler-water-conservation.html#storylink=cpy

Large-eddy simulation of propeller noise

NASA Astrophysics Data System (ADS)

Keller, Jacob; Mahesh, Krishnan

2016-11-01

We will discuss our ongoing work towards developing the capability to predict far field sound from the large-eddy simulation of propellers. A porous surface Ffowcs-Williams and Hawkings (FW-H) acoustic analogy, with a dynamic endcapping method (Nitzkorski and Mahesh, 2014) is developed for unstructured grids in a rotating frame of reference. The FW-H surface is generated automatically using Delaunay triangulation and is representative of the underlying volume mesh. The approach is validated for tonal trailing edge sound from a NACA 0012 airfoil. LES of flow around a propeller at design advance ratio is compared to experiment and good agreement is obtained. Results for the emitted far field sound will be discussed. This work is supported by ONR.

Large eddy simulation of hydrodynamic cavitation

NASA Astrophysics Data System (ADS)

Bhatt, Mrugank; Mahesh, Krishnan

2017-11-01

Large eddy simulation is used to study sheet to cloud cavitation over a wedge. The mixture of water and water vapor is represented using a homogeneous mixture model. Compressible Navier-Stokes equations for mixture quantities along with transport equation for vapor mass fraction employing finite rate mass transfer between the two phases, are solved using the numerical method of Gnanaskandan and Mahesh. The method is implemented on unstructured grid with parallel MPI capabilities. Flow over a wedge is simulated at Re = 200 , 000 and the performance of the homogeneous mixture model is analyzed in predicting different regimes of sheet to cloud cavitation; namely, incipient, transitory and periodic, as observed in the experimental investigation of Harish et al.. This work is supported by the Office of Naval Research.

[Results for SHEBA/FIRE

NASA Technical Reports Server (NTRS)

Valero, Francisco P. J.

2003-01-01

The Atmospheric Research Laboratory's Radiation Measurement System (RAMS) was on the NCAR C-130 aircraft in May and July 1998, collecting radiometric data on the science flights conducted in the vicinity of the Surface Heat Budget of the Arctic Ocean (SHEBA) ship. These measurements were part of the FIRE Arctic Cloud Experiment (FIRE ACE). Analysis of some of the data focused on the absorption, reflection, and transmittance of Arctic clouds, especially compared to model results. In order to assess the absorption of solar radiation by the clear and cloudy atmosphere in the Arctic the measurements from the radiometers were combined in pairs of above-cloud segments and below-cloud segments. To get these pairs, the data for all sixteen of the flights (8 in May and 8 in July) were examined for occurrences of low-altitude segments in proximity to high-altitude segments. The low-altitude data are then treated as measurements of the bottom of a layer and the high-altitude data are taken as measurements of the top of the layer. With measurements of the upwelling and downwelling irradiances above and below a layer one can determine the reflectance, transmittance, and absorptance of the layer. Attachment: Doelling, D.R., P. Minnis, D.A. Spangenberg, V. Chakrapani, A. Mahesh, S.K. Pope, and F.P.J. Valero, Cloud radiative forcing at the top of the atmosphere during FIRE ACE derived from AVHRR data, J. Geophys. Res. 106, 15,279-15,296,2001. Minnis, P., D.R. Doelling, D.A. Spangenberg, A. Mahesh, S.K. Pope, and F.P.J. Valero, AVHRR-derived cloud radiative forcing over the ARM NSA and SHEBA site during FIRE ACE, abstract submitted to the ARM Science Team Meeting, San Antonio, TX, M a . 13-17,2000. Pope, S.K., and F.P.J. Valero, Measured and modeled radiometric fluxes in the Arctic during FIRE-ACE, presented as a poster at the American Geophysical Union meeting, San Francisco, CA, Dec. 13-17, 1999. Pope, S.K., and F.P.J. Valero, Measured and modeled radiometric fluxes in the Arctic during FIRE-ACEy paper presented at SHEBA/FIRE Workshop, National Center for Atmospheric Research, Boulder, Colo., Apr. 17-20,2000.

An overview of PET/MR, focused on clinical applications.

PubMed

Catalano, Onofrio Antonio; Masch, William Roger; Catana, Ciprian; Mahmood, Umar; Sahani, Dushyant Vasudeo; Gee, Michael Stanley; Menezes, Leon; Soricelli, Andrea; Salvatore, Marco; Gervais, Debra; Rosen, Bruce Robert

2017-02-01

Hybrid PET/MR scanners are innovative imaging devices that simultaneously or sequentially acquire and fuse anatomical and functional data from magnetic resonance (MR) with metabolic information from positron emission tomography (PET) (Delso et al. in J Nucl Med 52:1914-1922, 2011; Zaidi et al. in Phys Med Biol 56:3091-3106, 2011). Hybrid PET/MR scanners have the potential to greatly impact not only on medical research but also, and more importantly, on patient management. Although their clinical applications are still under investigation, the increased worldwide availability of PET/MR scanners, and the growing published literature are important determinants in their rising utilization for primarily clinical applications. In this manuscript, we provide a summary of the physical features of PET/MR, including its limitations, which are most relevant to clinical PET/MR implementation and to interpretation. Thereafter, we discuss the most important current and emergent clinical applications of such hybrid technology in the abdomen and pelvis, both in the field of oncologic and non-oncologic imaging, and we provide, when possible, a comparison with clinically consolidated imaging techniques, like for example PET/CT.

Supernova Photometric Lightcurve Classification

NASA Astrophysics Data System (ADS)

Zaidi, Tayeb; Narayan, Gautham

2016-01-01

This is a preliminary report on photometric supernova classification. We first explore the properties of supernova light curves, and attempt to restructure the unevenly sampled and sparse data from assorted datasets to allow for processing and classification. The data was primarily drawn from the Dark Energy Survey (DES) simulated data, created for the Supernova Photometric Classification Challenge. This poster shows a method for producing a non-parametric representation of the light curve data, and applying a Random Forest classifier algorithm to distinguish between supernovae types. We examine the impact of Principal Component Analysis to reduce the dimensionality of the dataset, for future classification work. The classification code will be used in a stage of the ANTARES pipeline, created for use on the Large Synoptic Survey Telescope alert data and other wide-field surveys. The final figure-of-merit for the DES data in the r band was 60% for binary classification (Type I vs II).Zaidi was supported by the NOAO/KPNO Research Experiences for Undergraduates (REU) Program which is funded by the National Science Foundation Research Experiences for Undergraduates Program (AST-1262829).

Large Eddy Simulation of Ducted Propulsors in Crashback

NASA Astrophysics Data System (ADS)

Jang, Hyunchul; Mahesh, Krishnan

2009-11-01

Flow around a ducted marine propulsor is computed using the large eddy simulation methodology under crashback conditions. Crashback is an operating condition where a propulsor rotates in the reverse direction while the vessel moves in the forward direction. It is characterized by massive flow separation and highly unsteady propeller loads, which affect both blade life and maneuverability. The simulations are performed on unstructured grids using the discrete kinetic energy conserving algorithm developed by Mahesh at al. (2004, J. Comput. Phys 197). Numerical challenges posed by sharp blade edges and small blade tip clearances are discussed. The flow is computed at the advance ratio J=-0.7 and Reynolds number Re=480,000 based on the propeller diameter. Average and RMS values of the unsteady loads such as thrust, torque, and side force on the blades and duct are compared to experiment, and the effect of the duct on crashback is discussed.

Fluid-structure interaction of turbulent boundary layer over a compliant surface

NASA Astrophysics Data System (ADS)

Anantharamu, Sreevatsa; Mahesh, Krishnan

2016-11-01

Turbulent flows induce unsteady loads on surfaces in contact with them, which affect material stresses, surface vibrations and far-field acoustics. We are developing a numerical methodology to study the coupled interaction of a turbulent boundary layer with the underlying surface. The surface is modeled as a linear elastic solid, while the fluid follows the spatially filtered incompressible Navier-Stokes equations. An incompressible Large Eddy Simulation finite volume flow approach based on the algorithm of Mahesh et al. is used in the fluid domain. The discrete kinetic energy conserving property of the method ensures robustness at high Reynolds number. The linear elastic model in the solid domain is integrated in space using finite element method and in time using the Newmark time integration method. The fluid and solid domain solvers are coupled using both weak and strong coupling methods. Details of the algorithm, validation, and relevant results will be presented. This work is supported by NSWCCD, ONR.

A double-blind randomized placebo-controlled feasibility study evaluating individualized homeopathy in managing pain of knee osteoarthritis.

PubMed

Koley, Munmun; Saha, Subhranil; Ghosh, Shubhamoy

2015-07-01

Few homeopathic complexes seemed to produce significant effects in osteoarthritis; still, individualized homeopathy remained untested. We evaluated the feasibility of conducting an efficacy trial of individualized homeopathy in osteoarthritis. A prospective, parallel-arm, double-blind, randomized, placebo-controlled pilot study was conducted from January to October 2014 involving 60 patients (homeopathy, n = 30; placebo, n = 30) who were suffering from acute painful episodes of knee osteoarthritis and visiting the outpatient clinic of Mahesh Bhattacharyya Homeopathic Medical College and Hospital, West Bengal, India. Statistically significant reduction was achieved in 3 visual analog scales (measuring pain, stiffness, and loss of function) and Osteoarthritis Research Society International scores in both groups over 2 weeks (P < .05); however, group differences were not significant (P > .05). Overall, homeopathy did not appear to be superior to placebo; still, further rigorous evaluation in this design involving a larger sample size seems feasible in future. Clinical Trials Registry, India (CTRI/2014/05/004589). © The Author(s) 2015.

Quantum neural networks: Current status and prospects for development

NASA Astrophysics Data System (ADS)

Altaisky, M. V.; Kaputkina, N. E.; Krylov, V. A.

2014-11-01

The idea of quantum artificial neural networks, first formulated in [34], unites the artificial neural network concept with the quantum computation paradigm. Quantum artificial neural networks were first systematically considered in the PhD thesis by T. Menneer (1998). Based on the works of Menneer and Narayanan [42, 43], Kouda, Matsui, and Nishimura [35, 36], Altaisky [2, 68], Zhou [67], and others, quantum-inspired learning algorithms for neural networks were developed, and are now used in various training programs and computer games [29, 30]. The first practically realizable scaled hardware-implemented model of the quantum artificial neural network is obtained by D-Wave Systems, Inc. [33]. It is a quantum Hopfield network implemented on the basis of superconducting quantum interference devices (SQUIDs). In this work we analyze possibilities and underlying principles of an alternative way to implement quantum neural networks on the basis of quantum dots. A possibility of using quantum neural network algorithms in automated control systems, associative memory devices, and in modeling biological and social networks is examined.

Quadratic Electro-optic Effect in a Novel Nonconjugated Conductive Polymer, iodine-doped Polynorbornene

NASA Astrophysics Data System (ADS)

Narayanan, Ananthakrishnan; Thakur, Mrinal

2009-03-01

Quadratic electro-optic effect in a novel nonconjugated conductive polymer, iodine-doped polynorbornene has been measured using field-induced birefringence at 633 nm. The electrical conductivity^1 of polynorbornene increases by twelve orders of magnitude to about 0.01 S/cm upon doping with iodine. The electro-optic measurement has been made in a film doped at the medium doping-level. The electro-optic modulation signal was recorded using a lock-in amplifier for various applied ac voltages (4 kHz) and the quadratic dependence of the modulation on the applied voltage was observed. A modulation of about 0.01% was observed for an applied electric field of 3 V/micron for a 100 nm thick film The Kerr coefficient as determined is about 1.77x10-11m/V^2. This exceptionally large quadratic electro-optic effect has been attributed to the confinement of this charge-transfer system within a sub-nanometer dimension. 1. A. Narayanan, A. Palthi and M. Thakur, J. Macromol. Sci. -- PAC, accepted.

New Mineral Proves and Old Idea about Space Weathering

NASA Astrophysics Data System (ADS)

Martel, L. M. V.

2004-07-01

Discovered in a lunar meteorite, a new mineral named hapkeite honors the scientist, Bruce Hapke (Emeritis Professor at University of Pittsburgh), who nearly 30 years ago predicted the importance of vaporization as one of the processes in space weathering. The new iron silicide mineral (Fe2Si) was announced by the research team of Mahesh Anand (formerly at the University of Tennessee, Knoxville and now at the Natural History Museum, London), Larry Taylor (University of Tennessee, Knoxville), Mikhail Nazarov (Vernadsky Institute of Geochemistry and Analytical Chemistry, Moscow), Jinfu Shu, Ho-kwang Mao, and Russell Hemley (Carnegie Institution of Washington). This mineral likely formed by impact vaporization of the lunar soil and subsequent condensation of the iron and silicon into tiny metal grains. The researchers conclude that Fe-Si phases are more common in the lunar soil than previously thought. It is nanophase-sized Fe0, these Fe-Si phases, and other space weathering products that profoundly affect the optical properties of the lunar soil at visible and near infrared wavelengths and must be taken into account when interpreting remote sensing data of the Moon.

Distribution and abundance of mymarid parasitoids (Hymenoptera: Mymaridae) of Sophonia rufofascia Kuoh and Kuoh (Homoptera: Cicadellidae)in Hawaii

USGS Publications Warehouse

Yang, P.; Foote, D.; Alyokhin, A.V.; Lenz, L.; Messing, R.H.

2002-01-01

The abundance of mymarid parasitoids attacking the two-spotted leafhopper (Sophonia rufofascia [Kuoh and Kuoh]), a polyphagous pest recently adventive to Hawaii, was monitored using yellow sticky cards deployed in several areas on the islands of Kauai and Hawaii. The yellow cards captured Chaetomymar sp. nr bagicha Narayanan, Subba Rao, & Kaur and Schizophragma bicolor (Dozier), both adventive species, and Polynema sp. Haliday, which is endemic to Hawaii (Hymenoptera: Mymaridae). The former two species were most abundant at all sites. On Kauai, there was a negative correlation between the captures of C. sp. nr bagicha and those of Polynema sp. Throughout the season, the increase in parasitoid numbers generally followed the increase in leafhopper numbers. C. sp. nr. bagicha and S. bicolor showed distinct habitat preferences. Removal of Myrica faya Aiton, an invasive weed that is a highly preferred two-spotted leafhopper host, decreased the overall numbers of captured parasitoids, but led to a twofold increase in the ratio of trapped parasitoids/hosts in weed-free areas. ?? 2002 Elsevier Science (USA).

Is The Water Shortage Crisis Really One of the Most Dangerous?

NASA Astrophysics Data System (ADS)

Narayanan, M.

2010-12-01

Author of the 1998 book, Last Oasis: Facing Water Scarcity, Dr. Sandra Postel predicts big water availability problems as populations of so-called “water-stressed” countries jump perhaps six fold over the next 30 years. The author has reported on this in his previous AGU presentations. In the next four decades, more than half of the world’s population will have to deal with sever water shortages. The United States has been blessed with several large fresh water lakes. In spite of having this fresh water supply, some states like Arizona could be facing sever fresh water shortages in the next couple of decades. Sid Wilson, general manager of the Central Arizona Project has indicated "It's not a question of if there is a water shortage anymore. It is in reality, when there will be a water shortage. " Several states share water from the Colorado river. The river has limited water supply to cater to the needs of Arizona, Nevada, California, Colorado, New Mexico, Utah and Wyoming. World Health Organization, NASA, Department of the Interior, NOAA and several organizations have observed that there is a real water shortage crisis. This is because the world’s population has tripled in the twentieth century. This has resulted in a six-fold increase of water usage. Fresh water supply is limited. This is because water cannot be replaced with an alternative. It is important to observe that petroleum can be replaced with alternative fuel resources. It is necessary to recognize that fact that irrigation necessitates almost 65% to 70% of water withdrawal. Industry may utilize about 20% and domestic consumption is about 10% Evaporation from reservoirs is also a major factor, depending upon the climate and environment. Therefore there is an urgent need for all the countries to establish a strong, sound, sensible and sustainable management program for utilizing the available water supplies efficiently (Narayanan, 2008). References: 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.

Role of Cone Beam Computed Tomography in Evaluation of Radicular Cyst mimicking Dentigerous Cyst in a 7-year-old Child: A Case Report and Literature Review.

PubMed

Mahesh, B S; P Shastry, Shilpa; S Murthy, Padmashree; Jyotsna, T R

2017-01-01

To report a rare case of large radicular cyst-associated deciduous tooth and to discuss the importance of cone beam computed tomography (CBCT) in diagnosing the condition. Radicular cyst is the most common cyst affecting the permanent teeth, but its occurrence in deciduous teeth is rare. Most of the radicular cysts are asymptomatic and are discovered accidentally when radiographs are taken. Conventional radiographs show two-dimensional images of three-dimensional objects. Cone beam computed tomography provides undistorted three-dimensional information of hard tissues and gives adequate spatial resolution. A 7-year-old child, with a complaint of swelling in the maxillary anterior region, was diagnosed with radicular cyst in relation to primary maxillary right central incisor based on CBCT and histopathological features. Early diagnosis and prompt treatment of radicular cyst in primary dentition is important to prevent damage to permanent tooth. Mahesh BS, Shastry SP, Murthy PS, Jyotsna TR. Role of Cone Beam Computed Tomography in Evaluation of Radicular Cyst mimicking Dentigerous Cyst in a 7-year-old Child: A Case Report and Literature Review. Int J Clin Pediatr Dent 2017;10(2):213-216.

Large Eddy Simulation of Ducted Propulsors in Crashbac

NASA Astrophysics Data System (ADS)

Jang, Hyunchul; Mahesh, Krishnan

2008-11-01

Flow around a ducted marine propulsor is computed using the large eddy simulation methodology under crashback conditions. Crashback is an operating condition where a propulsor rotates in the reverse direction while the vessel moves in the forward direction. It is characterized by massive flow separation and highly unsteady propeller loads, which affect both blade life and maneuverability. The simulations are performed on unstructured grids using the algorithm developed by Mahesh at al. (2004, J. Comput. Phys 197). The flow is computed at the advance ratio J=-0.7 and Reynolds number Re=480,000 based on the propeller diameter. Average and RMS values of the unsteady loads such as thrust, torque, and side force on the blades and duct are compared to experiment. It is seen that even though effects of the duct on thrust and torque are not large enough, those on the side force are significant. The rms of side forces is much higher in the presence of the duct. Pressure distributions on blade surfaces and duct surface are examined and used to explain this effect. This work was supported by the United States Office of Naval Research under ONR Grant N00014-05-1-0003.

Efficiency of extracting stereo-driven object motions

PubMed Central

Jain, Anshul; Zaidi, Qasim

2013-01-01

Most living things and many nonliving things deform as they move, requiring observers to separate object motions from object deformations. When the object is partially occluded, the task becomes more difficult because it is not possible to use two-dimensional (2-D) contour correlations (Cohen, Jain, & Zaidi, 2010). That leaves dynamic depth matching across the unoccluded views as the main possibility. We examined the role of stereo cues in extracting motion of partially occluded and deforming three-dimensional (3-D) objects, simulated by disk-shaped random-dot stereograms set at randomly assigned depths and placed uniformly around a circle. The stereo-disparities of the disks were temporally oscillated to simulate clockwise or counterclockwise rotation of the global shape. To dynamically deform the global shape, random disparity perturbation was added to each disk's depth on each stimulus frame. At low perturbation, observers reported rotation directions consistent with the global shape, even against local motion cues, but performance deteriorated at high perturbation. Using 3-D global shape correlations, we formulated an optimal Bayesian discriminator for rotation direction. Based on rotation discrimination thresholds, human observers were 75% as efficient as the optimal model, demonstrating that global shapes derived from stereo cues facilitate inferences of object motions. To complement reports of stereo and motion integration in extrastriate cortex, our results suggest the possibilities that disparity selectivity and feature tracking are linked, or that global motion selective neurons can be driven purely from disparity cues. PMID:23325345

Object-oriented fault tree models applied to system diagnosis

NASA Technical Reports Server (NTRS)

Iverson, David L.; Patterson-Hine, F. A.

1990-01-01

When a diagnosis system is used in a dynamic environment, such as the distributed computer system planned for use on Space Station Freedom, it must execute quickly and its knowledge base must be easily updated. Representing system knowledge as object-oriented augmented fault trees provides both features. The diagnosis system described here is based on the failure cause identification process of the diagnostic system described by Narayanan and Viswanadham. Their system has been enhanced in this implementation by replacing the knowledge base of if-then rules with an object-oriented fault tree representation. This allows the system to perform its task much faster and facilitates dynamic updating of the knowledge base in a changing diagnosis environment. Accessing the information contained in the objects is more efficient than performing a lookup operation on an indexed rule base. Additionally, the object-oriented fault trees can be easily updated to represent current system status. This paper describes the fault tree representation, the diagnosis algorithm extensions, and an example application of this system. Comparisons are made between the object-oriented fault tree knowledge structure solution and one implementation of a rule-based solution. Plans for future work on this system are also discussed.

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.

Physiological loading of joints prevents cartilage degradation through CITED2

PubMed Central

Leong, Daniel J.; Li, Yong H.; Gu, Xiang I.; Sun, Li; Zhou, Zuping; Nasser, Philip; Laudier, Damien M.; Iqbal, Jameel; Majeska, Robert J.; Schaffler, Mitchell B.; Goldring, Mary B.; Cardoso, Luis; Zaidi, Mone; Sun, Hui B.

2011-01-01

Both overuse and disuse of joints up-regulate matrix metalloproteinases (MMPs) in articular cartilage and cause tissue degradation; however, moderate (physiological) loading maintains cartilage integrity. Here, we test whether CBP/p300-interacting transactivator with ED-rich tail 2 (CITED2), a mechanosensitive transcriptional coregulator, mediates this chondroprotective effect of moderate mechanical loading. In vivo, hind-limb immobilization of Sprague-Dawley rats up-regulates MMP-1 and causes rapid, histologically detectable articular cartilage degradation. One hour of daily passive joint motion prevents these changes and up-regulates articular cartilage CITED2. In vitro, moderate (2.5 MPa, 1 Hz) intermittent hydrostatic pressure (IHP) treatment suppresses basal MMP-1 expression and up-regulates CITED2 in human chondrocytes, whereas high IHP (10 MPa) down-regulates CITED2 and increases MMP-1. Competitive binding and transcription assays demonstrate that CITED2 suppresses MMP-1 expression by competing with MMP transactivator, Ets-1 for its coactivator p300. Furthermore, CITED2 up-regulation in vitro requires the p38δ isoform, which is specifically phosphorylated by moderate IHP. Together, these studies identify a novel regulatory pathway involving CITED2 and p38δ, which may be critical for the maintenance of articular cartilage integrity under normal physical activity levels.—Leong, D. J., Li, Y. H., Gu, X. I., Sun, L., Zhou, Z., Nasser, P., Laudier, D. M., Iqbal, J., Majeska, R. J., Schaffler, M. B., Goldring, M. B., Cardoso, L., Zaidi, M., Sun, H. B. Physiological loading of joints prevents cartilage degradation through CITED2. PMID:20826544

Mechanisms of the dimming and brightening aftereffects

PubMed Central

Bosten, Jenny M.; MacLeod, Donald I. A.

2013-01-01

Abstract Dimming and brightening aftereffects occur after exposure to a temporal luminance sawtooth stimulus: A subsequently presented steady test field appears to become progressively dimmer or brighter, depending on the polarity of the adapting sawtooth. Although described as “dimming” and “brightening,” it is plausible that a component of the aftereffects is based on contrast changes rather than on luminance changes. We conducted two experiments to reveal any contrast component. In the first we investigated whether the aftereffects result from the same mechanism that causes a polarity-selective loss in contrast sensitivity following luminance sawtooth adaptation. We manipulated test contrast: If a component of the aftereffect results from a polarity selective loss of contrast sensitivity we would expect that the aftereffects would differ in magnitude depending on the contrast polarity of the test fields. We found no effect of test-field polarity. In the second experiment we used an adapting sawtooth with a polarity consistent in contrast but alternating in luminance in order to induce a potential equivalent aftereffect of contrast. Again, we found no evidence that the aftereffects result from contrast adaptation. In a third experiment, we used S-cone isolating stimuli to discover whether there are S-cone dimming and brightening aftereffects. We found no aftereffects. However, in a fourth experiment we replicated Krauskopf and Zaidi's (1986) finding that adaptation to S-cone sawtooth stimuli affects thresholds for increment and decrement detection. The mechanism underlying the dimming and brightening aftereffects thus seems to be independent of the mechanism underlying the concurrent polarity selective reductions in contrast sensitivity. PMID:23695534

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.

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.

Designing Writing Exercises to Emphasize Environmental Education

NASA Astrophysics Data System (ADS)

Narayanan, M.

2008-12-01

In this presentation, the author stresses the importance of writing exercises to educate students in certain disciplines. The objective is to make the students become personally involved so that their educational experience is more geared towards a learning paradigm instead of a teaching paradigm. In addition to accumulating a wealth of knowledge the students also refine and expand their writing skills and abilities. One should be pragmatic in one's approach. In other words, the instructor should have a clear understanding of the skills the students need to develop. It is important to define the target and implementation mode while designing writing exercises. Effective learning can thus be combined with enthusiasm in classroom instructional development. It is extremely important that all undergraduate engineering students are provided with an adequate understanding and thorough background of the National Environmental Policy Act (NEPA) of 1969. At present, undergraduate students at Miami University of Ohio do not acquire any knowledge pertaining to this particular topic. The author proposes that a topic based on NEPA be introduced in the Fluid Mechanics Course at a Junior Level. The author believes that there is an absolute and urgent need for introducing the students to the fact that various documents such as EA (Environmental Assessment), EIS (Environmental Impact Statement), FONSI (Finding Of No Significant Impact), are an essential part of present-day workplace environment. In this presentation the author talks about introducing NEPA in the classroom. More than a decade ago Harvard University Professor Dr. Howard Gardner suggested the theory of Multiple Intelligences. Dr. Gardner proposed that eight different Intelligences accounted for the development of human potential (Gardner, 1983, 1993, 2000). Leading scholars in the area of Cognitive Science and Educational Methodologies also agree and have concluded that it is essential that students need to be taught 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.

Electrophysiological correlates of higher states of consciousness during sleep in long-term practitioners of the Transcendental Meditation program.

PubMed

Mason, L I; Alexander, C N; Travis, F T; Marsh, G; Orme-Johnson, D W; Gackenbach, J; Mason, D C; Rainforth, M; Walton, K G

1997-02-01

Standard ambulatory night sleep electroencephalograph (EEG) of 11 long-term practitioners of the Transcendental Meditation (TM) program reporting "higher states of consciousness" during sleep (the experimental group) was compared to that of nine short-term practitioners and 11 non-practitioners. EEG tracings during stages 3 and 4 sleep showed the experimental group to have: 1) theta-alpha activity simultaneously with delta activity and 2) decreased chin electromyograph (EMG) during deep sleep (p = 0.002) compared to short-term practitioners. Spectral analysis fast Fourier transform (FFT) data of the first three cycles showed that: 3) the experimental subjects had significantly greater theta 2 (6-8 Hz)-alpha 1 (8-10 Hz) relative power during stages 3 and 4 than the combined control groups [t(30) = 5.5, p = 0.0000008] with no difference in time in delta; 4) there was a graded difference across groups during stages 3 and 4 in theta 2-alpha 1 power, with experimentals having greater power than short-term practitioners, who in turn had greater power than non-practitioners [t(30) = 5.08, p = 0.00002]; and 5) experimentals also had increased rapid eye movement (REM) density during REM periods compared to short-term practitioners (p = 0.04). Previous studies have found increased theta-alpha EEG activity during reported periods of "transcendental consciousness" during the TM technique. In the Vedic tradition, as described by Maharishi Mahesh Yogi, transcendental consciousness is the first of a sequence of higher states. The maintenance of transcendental consciousness along with deep sleep is said to be a distinctive criterion of further, stabilized higher states of consciousness. The findings of this study are interpreted as physiological support for this model.

Treatment of fibromyalgia at the Maharishi Ayurveda Health Centre in Norway II--a 24-month follow-up pilot study.

PubMed

Rasmussen, Lars Bjørn; Mikkelsen, Knut; Haugen, Margaretha; Pripp, Are H; Fields, Jeremy Z; Førre, Øystein T

2012-05-01

Treatments offered at the Maharishi Ayurveda Health Centre in Norway are based on Maharishi Vedic Medicine (MVM). MVM is a consciousness-based revival by Maharishi Mahesh Yogi, the founder of the Transcendental Meditation (TM) program of the ancient Ayurvedic medicine tradition in India. To extend from 6 to 24 months, a pilot study of the effects of the treatment program at the Health Centre on fibromyalgia. Retesting 2 years after a clinical trial. In this intention to treat study, 31 women with a diagnosis of fibromyalgia received an individually tailored program of (1) physiological purification therapy (Maharishi Panchakarma) and (2) Ayurvedic recommendations regarding daily routine and diet including a novel approach to food intolerance. Five subjects chose to learn TM for stress reduction, pain management and personal development. All were recommended Ayurvedic herbal products for follow-up treatment. A modified Fibromyalgia Impact Questionnaire (FIQ) that included seven dimensions. Scores at 24 months follow-up were compared with pre-treatment scores. At 24-months follow-up, there were significant reductions (26% to 44%) in six of the seven fibromyalgia dimensions: impairment of working ability, pain, tiredness, morning tiredness, stiffness and anxiety. The 7th, depression, decreased 32% (borderline significant). At 24 months, the four subjects who continued practising TM, had almost no symptoms and significantly lower FIQ change scores (-92% to 97%) than the non-meditators on all outcomes. This pilot study suggests that the treatments and health promotion programs offered at the Maharishi Ayurveda Health Centre in Norway lead to long-term reductions in symptoms of fibromyalgia, which is considered a treatment-resistant condition, and further studies are warranted.

A Eulerian-Lagrangian Model to Simulate Two-Phase/Particulate Flows

NASA Technical Reports Server (NTRS)

Apte, S. V.; Mahesh, K.; Lundgren, T.

2003-01-01

Figure 1 shows a snapshot of liquid fuel spray coming out of an injector nozzle in a realistic gas-turbine combustor. Here the spray atomization was simulated using a stochastic secondary breakup model (Apte et al. 2003a) with point-particle approximation for the droplets. Very close to the injector, it is observed that the spray density is large and the droplets cannot be treated as point-particles. The volume displaced by the liquid in this region is significant and can alter the gas-phase ow and spray evolution. In order to address this issue, one can compute the dense spray regime by an Eulerian-Lagrangian technique using advanced interface tracking/level-set methods (Sussman et al. 1994; Tryggvason et al. 2001; Herrmann 2003). This, however, is computationally intensive and may not be viable in realistic complex configurations. We therefore plan to develop a methodology based on Eulerian-Lagrangian technique which will allow us to capture the essential features of primary atomization using models to capture interactions between the fluid and droplets and which can be directly applied to the standard atomization models used in practice. The numerical scheme for unstructured grids developed by Mahesh et al. (2003) for incompressible flows is modified to take into account the droplet volume fraction. The numerical framework is directly applicable to realistic combustor geometries. Our main objectives in this work are: Develop a numerical formulation based on Eulerian-Lagrangian techniques with models for interaction terms between the fluid and particles to capture the Kelvin- Helmholtz type instabilities observed during primary atomization. Validate this technique for various two-phase and particulate flows. Assess its applicability to capture primary atomization of liquid jets in conjunction with secondary atomization models.

“My children and I will no longer suffer from malaria”: a qualitative study of the acceptance and rejection of indoor residual spraying to prevent malaria in Tanzania

PubMed Central

2012-01-01

Background The objective of this study was to identify attitudes and misconceptions related to acceptance or refusal of indoor residual spraying (IRS) in Tanzania for both the general population and among certain groups (e.g., farmers, fishermen, community leaders, and women). Methods This study was a series of qualitative, semi-structured, in-depth interviews and focus group discussions conducted from October 2010 to March 2011 on Mainland Tanzania and Zanzibar. Three groups of participants were targeted: acceptors of IRS (those who have already had their homes sprayed), refusers (those whose communities have been sprayed, but refused to have their individual home sprayed), and those whose houses were about to be sprayed as part of IRS scale-up. Interviews were also conducted with farmers, fishermen, women, community leaders and members of non-government organizations responsible for community mobilization around IRS. Results Results showed refusers are a very small percentage of the population. They tend to be more knowledgeable people such as teachers, drivers, extension workers, and other civil servants who do not simply follow the orders of the local government or the sprayers, but are skeptical about the process until they see true results. Refusal took three forms: 1) refusing partially until thorough explanation is provided; 2) accepting spray to be done in a few rooms only; and 3) refusing outright. In most of the refusal interviews, refusers justified why their houses were not sprayed, often without admitting that they had refused. Reasons for refusal included initial ignorance about the reasons for IRS, uncertainty about its effectiveness, increased prevalence of other insects, potential physical side effects, odour, rumours about the chemical affecting fertility, embarrassment about moving poor quality possessions out of the house, and belief that the spray was politically motivated. Conclusions To increase IRS acceptance, participants recommended more emphasis on providing thorough public education, ensuring the sprayers themselves are more knowledgeable about IRS, and asking that community leaders encourage participation by their constituents rather than threatening punishment for noncompliance. While there are several rumours and misconceptions concerning IRS in Tanzania, acceptance is very high and continues to increase as positive results become apparent. Swahili Abstract Usuli Malengo mahususi ya utafiti huu ni kutambua tabia na imani potofu zinazopelekea kukubali au kutakaa upuliaziaji wa dawa ya kuua mbu majumbani (IRS) katika Tanzania kwa watu wote kwa ujumla na kwa makundi maalumu ya watu (kama wakulima, wavuvi, viongozi wa jamii na wanawake). Njia Utafiti huu ni mfululizo wa tafiti stahilifu zenye sehemu ya muundo, tafiti za kina na majadilianao ya vikundi vya walengwa yaliyofanyika Tanzania bara na Zanzibar kuanzia mwezi Oktoba, 2010 hadi mwezi Machi, 2011. Yalikuwepo makundi matatu ya walengwa: wanaokubali IRS (wale ambao nyumba zao zilikwisha kupulizwa dawa ya kuua mbu) wasiokubali (hii ni jamii iliyokwisha kupulizwa dawa na wale watu waliokataa dawa isipulizwe kwenye nyumba zao) na wale ambao nyumba zao zilikuwa zinakaribia kupulizwa dawa ikiwa ni kama sehemu ya kusambaza IRS. Usaili ulifanyika pia kwa wakulima, wavuvi, wanawake na viongozi wa jamii vile vile na kwa wanachama wa asasi zisizo za kiserikali waliokuwa wakiwajibika kwa IRS. Matokeo Matokeo yalionyesha kuwa waliokataa walikuwa ni asilimia ndogo sana ya watu wote. Walikuwa ni watu waelewa kama vile walimu, madereva, wafanyakazi katika miradi na watumishi wengine wa serikali ambao wanafuata amri kutoka kwa serikali yao au kwa wapuliza dawa lakini walikuwa na wasiwasi kuhusu mchakato huo mpaka waone matokeo yake. Waliokataa walikuwa katika maainisho matatu: 1) waliokataa kidogo mpaka wapewe maelezo; 2) waliokubali dawa ipulizwe kwenye vyumba vichache tu; 3) waliokataa katu katu. Mara kwa mara wengi wa wasailiwa waliokataa, walitoa sababu zao za kukataa nyumba zao zisipuliziwe, bila kukubali kuwa wamekataa kupuliziwa. Sababu za kukataa mwanzoni zilikuwa ni pamoja na; kutokuwa na uhakika kuhusu dawa inavyofanya kazi, kutoelewa matokeo yake, kuongezeka kwa kuenea kwa wadudu wengine. Athari nyingine mbaya zilizoonekana ni: harufu, tetesi kuhusu kemikali zinazoathiri urutubishwaji, aibu ya kutolewa vitu vyao vyenye thamani duni kutoka kwenye nyumba zao na imani kuwa dawa hiyo ilihamasishwa kisiasa zaidi. Hitimisho Ili kuongeza kukubalika kwa IRS, washiriki wanasisitiza zaidi kuzitoa dawa hizo kwa kuwaelimisha watu kwanza, kuhakikisha kuwa wanaonyunyuza dawa hiyo wana ujuzi wa kutosha kuhusu dawa yenyewe, kuwaomba viongozi wa jamii wawatie moyo wanajamii katika kaya zao badala ya kuwatishia na kuwalazimisha. Pamoja na kwamba kuna tetesi na watu kuelewa visivyo kuhusu IRS, kukubalika ni kukubwa na kunaendelea kuonyehsa kuwa na mafanikio chanya. PMID:22747610

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 prevents metabolic impairment.

Appearance of cicada fauna (Homoptera: Cicadoidea) by altitudes in Johor National Park, Mount Ledang, Johor

NASA Astrophysics Data System (ADS)

Tahir, Aliadi Mohd; Sulaiman, Azman

2015-09-01

A total of 31 cicada species in 15 genera under two families (Cicadidae, 27 species in 11 genera; Tibicinidae, four species in three genera) was recorded for Johor National Park, Mount Ledang, Johor. This was based on 666 individuals were obtained through six sampling occasions in November 2012 until October 2013, each time using light trap set in six sampling locations (L1, L2, L3, L4a, L4b, L4c) that were selected based on altitudes. The most common and abundant species in L1 is Pomponia sp1 and recognized as new species that need to be described as new to science. Orientopsaltria saudarapadda Duffles & Zaidi appeared as the most common and abundant species in L2, represented by 21 individuals which covers 34.43 % of the total cicadas specimen in that area. In the location of L3, Dundubia vaginata (Fabricius) appeared as the most abundant species represented by 37 individuals or 26.81% while Abroma maculicollis Guerin appeared as the most common species. Shannon's Species Diversity Index (H') in L3 was the highest (H'=2.28) followed by L4b (H'=2.21), L2 (H'=1.93) L4a (H'=1.92), L4c (H'=1.84) and L1 (H'=1.58), and the evenness index in L1 was the highest (E= 0.88), followed by L4b (E= 0.79), L3 (E= 0.77), L2 (E= 0.75), L4c (E= 0.74) and L4a (E= 0.79). Margalef Species Richness Index in L3 was the highest (R'=3.65), followed by oleh L4b (R'=3.01), L4a (R'=2.97), L2 (R'=2.92), L4c (R'=2.4), and L1 (R'=2.01). Generally shows that L3 at the altitude 350 m appear as the best sampling site for cicadas species in Mount Ledang Johor with the highest value of species diversity and richness index.

An investigation into field effects of consciousness from the perspectives of Maharishi's Vedic Science and physics

NASA Astrophysics Data System (ADS)

Kleinschnitz, Kurt Warren

1997-05-01

A long-range field effect of consciousness has been reported repeatedly in the scientific literature over the past twenty years. This phenomenon is called the Maharishi Effect, after Maharishi Mahesh Yogi, the first to predict it. The Maharishi Effect is the phenomenon of improved societal trends resulting from the practice of the Transcendental Meditationoler program or group practice of the TM-Sidhioler program by a small fraction of a population. The Maharishi Effect is fundamentally a phenomenon of radiation of evolutionary influence arising from the enlivenment of pure consciousness, the unified field of natural law, in the perspective of Maharishi's Vedic Science. This perspective is corroborated by forty-three published or presented papers reporting on results of Maharishi Effect interventions world-wide at city, national, international, and global scales. Present day standard- model physics and physiology do not account for the outcomes of the research on the Maharishi Effect. Because the observed societal impact of the Maharishi Effect influence must be based in an impact on the individual, and investigators report detection of the effect in individual physiological measurements, a simple robust indicator for the effect might aid physiologists and physicists in the effort to extend their sciences to include such field effects of consciousness. Thus, this dissertation reports on two experiments investigating simple, robust, objective indicators for the effect. The dissertation concludes on a practical note with a description of the promise, available through concerted utilization of the knowledge and technologies of consciousness in Maharishi's Vedic Science, for enhanced national and global security in the face of unprecedented nuclear, biological, and genetic threats for which the modern sciences offer few sensible solutions. ftnolerTranscendental Meditation and TM-Sidhi are service marks registered in the United States Patent and Trademark Office, licensed to Maharishi Vedic Education Development Corporation, and used under sublicense.

Treatment of fibromyalgia at the Maharishi Ayurveda Health Centre in Norway. A six-month follow-up study.

PubMed

Rasmussen, L B; Mikkelsen, K; Haugen, M; Pripp, A H; Førre, Ø T

2009-01-01

Treatments offered at the Maharishi Ayurveda Health Centre in Norway are based on Maharishi Vedic medicine, which is also known as Maharishi Ayurveda. It is a consciousness based revival of the ancient Ayurvedic medicine tradition in India and is established by Maharishi Mahesh Yogi, the founder of the Transcendental Meditation (TM) technique. To conduct a pilot study of the effect of the treatment program at the Health Centre on fibromyalgia patients. Thirty-one women with diagnosed fibromyalgia received an individually designed Maharishi Vedic physiological purification therapy. All subjects received personal advice on diet based on Ayurvedic principles, including a novel approach to food into-lerance, and daily routines. In addition they were offered instruction in TM (for stress and pain management and personal development) (four subjects started), and recommended Ayurvedic herbal food products for home treatment. A modified Fibromyalgia Impact Questionnaire included a visual analogue scale for each of the seven outcomes: working ability, generalised pain, tiredness, stiffness, tiredness on arising, anxiety and depression. Pre-treatment scores were compared with scores at six-month follow-up for levels of statistical significance. Twenty-eight subjects (90%) completed the follow-up. The outcome measures were reduced by 25 to 46% by the study's endpoint: working ability (p<0.002), pain (p<0.001), tiredness (p<0.001), morning tiredness (p<0.001), stiffness (p<0.005), anxiety (p<0.136), and depression (p<0.001). A group of five excellent responders including all four participants who started to practise TM, had almost no symptoms by the endpoint. Compared to the non-meditating control group the TM-subgroup showed statistically significant improvements for all outcome measures except depression. In this pilot study fibromyalgia patients undergoing treatment at Maharishi Ayurveda Health Centre in Norway showed significant improvements six months post treatment. Because fibromyalgia is considered a treatment-resistant condition, these encouraging results warrant further research.

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/

Detecting signatures of cosmological recombination and reionization in the cosmic radio background

NASA Astrophysics Data System (ADS)

Subrahmanyan, Ravi; Shankar Narayana Rao, Udaya; Sathyanarayana Rao, Mayuri; Singh, Saurabh

2015-08-01

Evolution of the baryons during the Epochs of cosmological Recombination and Reionization has left traces in the cosmic radio background in the form of spectral distortions (Sunyaev & Chluba 2008 Astron. Nachrichten, 330, 657; Pritchard & Loeb 2012 Rep Prog Phys 75(8):086901). The spectral signature depends on the evolution in the ionization state in hydrogen and helium and on the spin temperature of hydrogen. These probe the physics of energy release beyond the last scattering surface at redshifts exceeding 1090 and the nature of the first sources and gas evolution down to redshift about 6. The spectral distortions are sensitive to the nature of the first stars, ultra-dwarf galaxies, accreting compact objects, and the evolving ambient radiation field: X-rays and UV from the first sources. Detection of the all-sky or global spectral distortions in the radio background is hence a probe of cosmological recombination and reionization.We present new spectral radiometers that we have purpose designed for precision measurements of spectral distortions at radio wavelengths. New antenna elements include frequency independent and electrically small fat-dipole (Raghunathan et al. 2013 IEEE TAP, 61, 3411) and monopole designs. Receiver configurations have been devised that are self-calibratable (Patra et al. 2013 Expt Astron, 36, 319) so that switching of signal paths and of calibration noise sources provide real time calibration for systematics and receiver noise. Observing strategies (Patra et al. arXiv:1412.7762) and analysis methods (Satyanarayana Rao et al. arXiv:1501.07191) have been evolved that are capable of discriminating between the cosmological signals and the substantially brighter foregrounds. We have also demonstrated the value of system designs that exploit advantages of interferometer detection (Mahesh et al. arXiv:1406.2585) of global spectral distortions.Finally we discuss how the Square Kilometer Array stations may be outfitted with precision spectral radiometer outriggers (Subrahmanyan et al. arXiv:1501.04340) to provide the zero-spacing measurement sets, complement the interferometer visibilities and give the SKA a capability for measurements of cosmic radio background spectral distortions.

Direct numerical simulation of auto-ignition of a hydrogen vortex ring reacting with hot air

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

Doom, Jeff; Mahesh, Krishnan

2009-04-15

Direct numerical simulation (DNS) is used to study chemically reacting, laminar vortex rings. A novel, all-Mach number algorithm developed by Doom et al. [J. Doom, Y. Hou, K. Mahesh, J. Comput. Phys. 226 (2007) 1136-1151] is used. The chemical mechanism is a nine species, nineteen reaction mechanism for H{sub 2}/air combustion proposed by Mueller et al. [M.A. Mueller, T.J. Kim, R.A. Yetter, F.L. Dryer, Int. J. Chem. Kinet. 31 (1999) 113-125]. Diluted H{sub 2} at ambient temperature (300 K) is injected into hot air. The simulations study the effect of fuel/air ratios, oxidizer temperature, Lewis number and stroke ratio (ratiomore » of piston stroke length to diameter). Results show that auto-ignition occurs in fuel lean, high temperature regions with low scalar dissipation at a 'most reactive' mixture fraction, {zeta}{sub MR} (Mastorakos et al. [E. Mastorakos, T.A. Baritaud, T.J. Poinsot, Combust. Flame 109 (1997) 198-223]). Subsequent evolution of the flame is not predicted by {zeta}{sub MR}; a most reactive temperature T{sub MR} is defined and shown to predict both the initial auto-ignition as well as subsequent evolution. For stroke ratios less than the formation number, ignition in general occurs behind the vortex ring and propagates into the core. At higher oxidizer temperatures, ignition is almost instantaneous and occurs along the entire interface between fuel and oxidizer. For stroke ratios greater than the formation number, ignition initially occurs behind the leading vortex ring, then occurs along the length of the trailing column and propagates toward the ring. Lewis number is seen to affect both the initial ignition as well as subsequent flame evolution significantly. Non-uniform Lewis number simulations provide faster ignition and burnout time but a lower maximum temperature. The fuel rich reacting vortex ring provides the highest maximum temperature and the higher oxidizer temperature provides the fastest ignition time. The fuel lean reacting vortex ring has little effect on the flow and behaves similar to a non-reacting vortex ring. (author)« less

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://epublications.marquette.edu/conversations/vol43/iss1/9 Arum, Richard and Roksa, Josipa (2011) Academically Adrift: Limited Learning on College Campuses. Chicago, Illinois: University of Chicago Press. (ISBN 9780226028569)

SURFACE WATER AND GROUND WATER QUALITY MONITORING FOR RESTORATION OF URBAN LAKES IN GREATER HYDERABAD, INDIA

NASA Astrophysics Data System (ADS)

Mohanty, A. K.

2009-12-01

SURFACE WATER AND GROUND WATER QUALITY MONITORING FOR RESTORATION OF URBAN LAKES IN GREATER HYDERABAD, INDIA A.K. Mohanty, K. Mahesh Kumar, B. A. Prakash and V.V.S. Gurunadha Rao Ecology and Environment Group National Geophysical Research Institute, (CSIR) Hyderabad - 500 606, India E-mail:atulyakumarmohanty@yahoo.com Abstract: Hyderabad Metropolitan Development Authority has taken up restoration of urban lakes around Hyderabad city under Green Hyderabad Environment Program. Restoration of Mir Alam Tank, Durgamcheruvu, Patel cheruvu, Pedda Cheruvu and Nallacheruvu lakes have been taken up under the second phase. There are of six lakes viz., RKPuramcheruvu, Nadimicheruvu (Safilguda), Bandacheruvu Patelcheruvu, Peddacheruvu, Nallacheruvu, in North East Musi Basin covering 38 sq km. Bimonthly monitoring of lake water quality for BOD, COD, Total Nitrogen, Total phosphorous has been carried out for two hydrological cycles during October 2002- October 2004 in all the five lakes at inlet channels and outlets. The sediments in the lake have been also assessed for nutrient status. The nutrient parameters have been used to assess eutrophic condition through computation of Trophic Status Index, which has indicated that all the above lakes under study are under hyper-eutrophic condition. The hydrogeological, geophysical, water quality and groundwater data base collected in two watersheds covering 4 lakes has been used to construct groundwater flow and mass transport models. The interaction of lake-water with groundwater has been computed for assessing the lake water budget combining with inflow and outflow measurements on streams entering and leaving the lakes. Individual lake water budget has been used for design of appropriate capacity of Sewage Treatment Plants (STPs) on the inlet channels of the lakes for maintaining Full Tank Level (FTL) in each lake. STPs are designed for tertiary treatment i.e. removal of nutrient load viz., Phosphates and Nitrates. Phosphates are removed through addition of Alum to the influent stream to the STPs whereas Nitrates reduction is achieved by sending the treated wastewater from the STP through a wetland before entering the lake. STP Capacity ranging from 2-10 MLD have been recommended depending on lake water budget of individual lake and considering surrounding urbanization. Sediment nutrient data has helped for deciding the need for dredging of lake bed for removal of phosphates. Key Words: Lake water budget, Eutrophication, Trophic Status Index, Urban Lakes Restoration

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 worse matches. Our models provide testable predictions of the physical masses, dust temperatures, CO linewidths and location on the MBH-Mbulge relation of DOGs. Finally, we provide public SED templates derived from these simulations. This paper is dedicated to the original DOG himself, Cordozar Calvin Broadus, Jr. E-mail: dnarayanan@cfa.harvard.edu ‡ CfA Fellow. § Carnegie Fellow. ¶ W. M. Keck Postdoctoral Fellow. ∥ Miller Fellow. ** Hubble Fellow.

Learn, how to learn

NASA Astrophysics Data System (ADS)

Narayanan, M.

2002-12-01

Ernest L. Boyer, in his 1990 book, "Scholarship Reconsidered: Priorities of the Professorate" cites some ground breaking studies and offers a new paradigm that identifies the need to recognize the growing conversation about teaching, scholarship and research in the Universities. The use of `ACORN' model suggested by Hawkins and Winter to conquer and mastering change, may offer some helpful hints for the novice professor, whose primary objective might be to teach students to `learn how to learn'. Action : It is possible to effectively change things only when a teaching professor actually tries out a new idea. Communication : Changes are successful only when the new ideas effectively communicated and implemented. Ownership : Support for change is extremely important and is critical. Only strong commitment for accepting changes demonstrates genuine leadership. Reflection : Feedback helps towards thoughtful evaluation of the changes implemented. Only reflection can provide a tool for continuous improvement. Nurture : Implemented changes deliver results only when nurtured and promoted with necessary support systems, documentation and infrastructures. Inspired by the ACORN model, the author experimented on implementing certain principles of `Total Quality Management' in the classroom. The author believes that observing the following twenty principles would indeed help the student learners how to learn, on their own towards achieving the goal of `Lifelong Learning'. The author uses an acronym : QUOTES : Quality Underscored On Teaching Excellence Strategy, to describe his methods for improving classroom teacher-learner participation. 1. Break down all barriers. 2. Create consistency of purpose with a plan. 3. Adopt the new philosophy of quality. 4. Establish high Standards. 5. Establish Targets / Goals. 6. Reduce dependence on Lectures. 7. Employ Modern Methods. 8. Control the Process. 9. Organize to reach goals. 10. Prevention vs. Correction. 11. Periodic Improvements. 12. 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

It is important to recognize technical writing as a creative vehicle to communicate with the audience. It is indeed possible to motivate a reluctant learner by encouraging student writing combined with reading and research. John Kosakowski is of the opinion that writing assignments actually help to strengthen the self-confidence of a lethargic learner (Kosakowski, 1998). Researchers in the area of cognitive science and educational psychology are also of the opinion that encouraging students to writing actually helps the learners cultivate a positive attitude toward the subject matter in question. One must also recognize the fact that the students are indeed very reluctant to devote time and effort that requiress descriptive long writing assignments. One has to be more creative towards assignments that utilize problem-solving pedagogy (Saxe, 1988; Senge, 1990; Sims, 1995; Young & Young, 1999). Education World writer Gloria Chaika (Chaika, 2000) states that “Talent is important, but practice creates the solid base that allows that unique talent to soar. Like athletes, writers learn by doing. Good writing requires the same kind of dedicated practice that athletes put in. Young writers often lack the support they need to practice writing and develop their talent to the fullest, though.” Writing assignments have several key elements and the author has outlined below, some ideas for conducting assessment. 1. Identification of a purpose. 2. Focusing on the subject matter. 3. Attracting the attention of audience. 4. Format, flow and familiarity of the structure. 5. Observation of formality, voice and tone. 6. Promotion of critical thinking. 7. Importance of Logic and evidence-based reasoning. 8. Follows a realistic time line. 9. Process and procedure are properly outlined. 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. 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

The author strongly believes that when one provides students more opportunity to write and publish, one actually is helping those students learn better. Writing in reality reinforces the knowledge acquired and clarifies fuzzy, indistinct and indefinable points. In a Learning Paradigm or a Discovery Paradigm, it is observed that evaluation is holistic, and student success outcomes are those that are actually measured. Many scholars have recommended and supported a value-added concept of education by doing assessments before, during, and after a course (Barr & Tagg, 1995). Other scholars have argued that achievement of educational objectives is becoming less and less measurable whereas the need for accountability is rising to the surface more frequently. The literature supports our intuitive belief that education in a new learning paradigm will prepare students for the work ahead of them (Cox, Grasha, & Richlin 1997, March). Technical writing has been a part of engineering education for a long time. Regardless, it appears that engineering students are more interested in spending productive time learning the mathematical aspects of subject matter. The students are reluctant to devote time and effort that involves descriptive writing. The trend is to develop an interactive problem-solving pedagogy that encourages the development of learner’s creativity, understanding, written and oral communication skills (Saxe, 1988; Senge, 1990; Sims, 1995; Young & Young, 1999). It is essential for the students to recognize the fact that writing indeed enhances their grasp over technical content. The author has outlined seven areas for assessing a writing assignment. 1. The student writing has an identified a specific focus on a given purpose. 2. The author has indicated an audience for the writing assignment. 3. The writer has specified conventions for format, flow and structure. 4. The learner has documented conventions for formality, voice and tone. 5. The individual has 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

The population of United States has more than doubled over the past 50 years. The need for water however, has tripled. The EPA estimates that more than 36 states face water shortage during the forthcoming years. The EPA has prepared a plan for achieving environmental and energy performance. This will be coupled with leadership and accountability. Carbon neutrality is also of prime importance. The objective is to focus on six important, essential areas. 1. Efficient use of already available energy resources. 2. Intelligent water consumption and focusing on water conservation. 3. Expand the use of renewable energy resources. 4. Explore innovative transportation systems and methodologies. 5. Change building codes and promote high performance sustainable buildings. 6. Focus on developing creative environment management systems. Greenhouse gases such as carbon dioxide occur naturally in the atmosphere. Carbon dioxide is also emitted to the atmosphere through a variety of natural processes and also some human activities. However, fluorinated gases are emitted to the atmosphere solely through human activities, because they are created by humans. It is very important to observe that water conservation is probably the most cost-effective way to reduce our demand for water. Furthermore, it is certainly environmentally justifiable. Water conservation also means, less use of water. This in turn, results in less strain on the city sewage treatment plants. This may also imply that one uses less energy for heating water. For example, the city of Los Angeles has grown by more than a million over the past thirty years. Regardless, the city still uses almost the same amount of water even now. The Environmental Protection Agency has a plan called E2PLAN. It is EPA's plan for achieving energy and environmental performance, leadership, accountability, and carbon neutrality. In June 2011, the EPA published a comprehensive, multi-year planning document called Strategic Sustainability 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

This is an encore presentation of what was presented at the 2012 AGU International Conference. It was entitled: 'The Importance of Water Conservation in the 21st Century.' The poster presentation, however, has been redesigned and reorganized with new, revised perspectives. The importance of water conservation principles has been emphasized. The population of United States has more than doubled over the past 50 years. The need for water however, has tripled. The EPA estimates that more than 36 states face water shortage during the forthcoming years. The EPA has prepared a plan for achieving environmental and energy performance. This will be coupled with leadership and accountability. Carbon neutrality is also of prime importance. The objective is to focus on six important, essential areas. 1. Efficient use of already available energy resources. 2. Intelligent water consumption and focusing on water conservation. 3. Expand the use of renewable energy resources. 4. Explore innovative transportation systems and methodologies. 5. Change building codes and promote high performance sustainable buildings. 6. Focus on developing creative environment management systems. Greenhouse gases such as carbon dioxide occur naturally in the atmosphere. Carbon dioxide is also emitted to the atmosphere through a variety of natural processes and also some human activities. However, fluorinated gases are emitted to the atmosphere solely through human activities, because they are created by humans. It is very important to observe that water conservation is probably the most cost-effective way to reduce our demand for water. Furthermore, it is certainly environmentally justifiable. The Environmental Protection Agency has a plan called E2PLAN. It is EPA's plan for achieving energy and environmental performance, leadership, accountability, and carbon neutrality. In June 2011, the EPA published a comprehensive, multi-year planning document called Strategic Sustainability Performance Plan. The 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

Provost David L. Potter of George Mason University chaired a joint task force and presented a report entitled ``Powerful Partnerships : A Shared Responsibility for Learnin'' in June 1998. The main goal is to make a difference in the quality of student learning. Further, it is important to assess this difference and document it. Clifford O. Young, Sr., & Laura Howzell Young of California State University, San Bernardino argue that a new paradigm for assessment, a learning paradigm, must be constructed to measure the success of new kinds of educational practices. Using two survey instruments, the Instruction Model Learning Model Questionnaire (IMLMQ) and the Student Evaluation of Teaching Effectiveness (SETE), they compared students' responses to the course when taught with traditional methods and with interactive methods. The results suggest that neither instrument effectively measures the kinds of learning promoted under the new paradigm. Linn, Baker, & Dunbar recommend that these newer assessment practices should be more authentic, that is, to involve students in the actual or simulated performance of a task or the documentation of the desired competency in a portfolio. Cerbin says that one of the most unfortunate consequences of a summative emphasis is that it inhibits open and productive discussions about teaching; in essence, it marginalizes the types of activity that could lead to better teaching (Cerbin, 1992). William Cerbin, who is the Director of the Center for Effective Teaching and learning, University Assessment Coordinator, and Professor of Psychology at the University of Wisconsin-LaCrosse is a recognized expert in the areas of cognition, language, and development. Edgerton, Hutchings, & Quinlan indicate that Teaching Portfolios may contain evidence of students' learning, but such information is optional, and when included, it may be only one of many pieces of material. Seldin, also supports this and stresses that the interplay between the instructor 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

One of the current challenges in underwater acoustic array signal processing is the detection of quiet targets in the presence of noise. In order to enable robust detection, one of the key processing steps requires data and replica whitening. This, in turn, involves the eigen-decomposition of the sample spectral matrix, Cx = 1/K xKX(k)XH(k) where X(k) denotes a single frequency snapshot with an element for each element of the array. By employing the singular value decomposition (SVD) method, the eigenvectors and eigenvalues can be determined directly from the data without computing the sample covariance matrix, reducing the computational requirements formore » a given level of accuracy (van Trees, Optimum Array Processing). (Recall that the SVD of a complex matrix A involves determining V, , and U such that A = U VH where U and V are orthonormal and is a positive, real, diagonal matrix containing the singular values of A. U and V are the eigenvectors of AAH and AHA, respectively, while the singular values are the square roots of the eigenvalues of AAH.) Because it is desirable to be able to compute these quantities in real time, an efficient technique for computing the SVD is vital. In addition, emerging multicore processors like graphical processing units (GPUs) are bringing parallel processing capabilities to an ever increasing number of users. Since the computational tasks involved in array signal processing are well suited for parallelization, it is expected that these computations will be implemented using GPUs as soon as users have the necessary computational tools available to them. Thus, it is important to have an SVD algorithm that is suitable for these processors. This work explores the effectiveness of two different parallel SVD implementations on an NVIDIA Tesla C2050 GPU (14 multiprocessors, 32 cores per multiprocessor, 1.15 GHz clock - peed). The first algorithm is based on a two-step algorithm which bidiagonalizes the matrix using Householder 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

Large Eddy Simulation of Crashback in Marine Propulsors

NASA Astrophysics Data System (ADS)

Jang, Hyunchul

Crashback is an operating condition to quickly stop a propelled vehicle, where the propeller is rotated in the reverse direction to yield negative thrust. The crashback condition is dominated by the interaction of the free stream flow with the strong reverse flow. This interaction forms a highly unsteady vortex ring, which is a very prominent feature of crashback. Crashback causes highly unsteady loads and flow separation on the blade surface. The unsteady loads can cause propulsor blade damage, and also affect vehicle maneuverability. Crashback is therefore well known as one of the most challenging propeller states to analyze. This dissertation uses Large-Eddy Simulation (LES) to predict the highly unsteady flow field in crashback. A non-dissipative and robust finite volume method developed by Mahesh et al. (2004) for unstructured grids is applied to flow around marine propulsors. The LES equations are written in a rotating frame of reference. The objectives of this dissertation are: (1) to understand the flow physics of crashback in marine propulsors with and without a duct, (2) to develop a finite volume method for highly skewed meshes which usually occur in complex propulsor geometries, and (3) to develop a sliding interface method for simulations of rotor-stator propulsor on parallel platforms. LES is performed for an open propulsor in crashback and validated against experiments performed by Jessup et al. (2004). The LES results show good agreement with experiments. Effective pressures for thrust and side-force are introduced to more clearly understand the physical sources of thrust and side-force. Both thrust and side-force are seen to be mainly generated from the leading edge of the suction side of the propeller. This implies that thrust and side-force have the same source---the highly unsteady leading edge separation. Conditional averaging is performed to obtain quantitative information about the complex flow physics of high- or low-amplitude events. The events for thrust and side force show the same tendency. The conditional averages show that during high amplitude events, the vortex ring core is closer to the propeller blades, the reverse flow induced by the propeller rotation is lower, the forward flow is higher at the root of the blades, and leading and trailing edge flow separations are larger. The instantaneous flow field shows that during low amplitude events, the vortex ring is more axisymmetric and the stronger reverse flow induced by the vortex ring suppresses the forward flow so that flow separation on the blades is smaller. During high amplitude events, the vortex ring is less coherent and the weaker reverse flow cannot overcome the forward flow. The stronger forward flow makes flow separation on the blades larger. The effect of a duct on crashback is studied with LES. Thrust mostly arises from the blade surface, but most of side-force is generated from the duct surface. Both mean and RMS of pressure are much higher on inner surface of duct, especially near blade tips. This implies that side-force on the ducted propulsor is caused by the blade-duct interaction. Strong tip leakage flow is observed behind the suction side at the tip gap. The physical source of the tip leakage flow is seen to be the large pressure difference between pressure and suction sides. The conditional average for high amplitude event shows consistent results; the tip leakage flow and pressure difference are significantly higher when thrust and side-force are higher. A sliding interface method is developed to allow simulations of rotor-stator propulsor in crashback. The method allows relative rotations between different parts of the computational grid. Search algorithm for sliding elements, data structures for message passing, and accurate interpolation scheme at the sliding interface are developed for arbitrary shaped unstructured grids on parallel computing platforms. Preliminary simulations of open propulsor in crashback show reasonable performance.

PREFACE: Cell-substrate interactions Cell-substrate interactions

NASA Astrophysics Data System (ADS)

Gardel, Margaret; Schwarz, Ulrich

2010-05-01

One of the most striking achievements of evolution is the ability to build cellular systems that are both robust and dynamic. Taken by themselves, both properties are obvious requirements: robustness reflects the fact that cells are there to survive, and dynamics is required to adapt to changing environments. However, it is by no means trivial to understand how these two requirements can be implemented simultaneously in a physical system. The long and difficult quest to build adaptive materials is testimony to the inherent difficulty of this goal. Here materials science can learn a lot from nature, because cellular systems show that robustness and dynamics can be achieved in a synergetic fashion. For example, the capabilities of tissues to repair and regenerate are still unsurpassed in the world of synthetic materials. One of the most important aspects of the way biological cells adapt to their environment is their adhesive interaction with the substrate. Numerous aspects of the physiology of metazoan cells, including survival, proliferation, differentiation and migration, require the formation of adhesions to the cell substrate, typically an extracellular matrix protein. Adhesions guide these diverse processes both by mediating force transmission from the cell to the substrate and by controlling biochemical signaling pathways. While the study of cell-substrate adhesions is a mature field in cell biology, a quantitative biophysical understanding of how the interactions of the individual molecular components give rise to the rich dynamics and mechanical behaviors observed for cell-substrate adhesions has started to emerge only over the last decade or so. The recent growth of research activities on cell-substrate interactions was strongly driven by the introduction of new physical techniques for surface engineering into traditional cell biological work with cell culture. For example, microcontact printing of adhesive patterns was used to show that cell fate depends not on the amount of ligand for adhesion receptors, but on its spatial distribution [1]. New protocols for the preparation of soft elastic substrates were essential to show that adhesion structures and cytoskeleton of adherent cells strongly adapt to substrate stiffness [2], with dramatic effects for cellular decision making. For example, it has been shown recently that differentiation of mesenchymal stem cells is strongly influenced by substrate stiffness [3]. Thus, physical factors appear to be equally important as biochemical ones in determining the cellular response to its substrate [4]. The introduction of novel physical techniques not only opened up completely new perspectives regarding biological function, it also introduced a new quantitative element into this field. For example, the availability of soft elastic substrates with controlled stiffness allows us to reconstruct cellular traction forces and to correlate them with other cellular features. This development enables modeling approaches to work in close contact with experimental data, thus opening up the perspective that the field of cell-substrate interactions will become a quantitative and predictive science in the future. Because physical research into cell-substrate interactions has become one of the fastest growing research areas in cellular biophysics and materials science, we believe that it is very timely that this special issue gathers some of the on-going research effort in this field. In contrast to the non-living world, cellular systems usually interact with their environment through specific adhesion, mainly based on adhesion receptors from the integrin family. During recent years, force spectroscopy has emerged as one of the main methods to study the physics of specific adhesion. In this special issue, single cell force spectroscopy is used by Boettiger and Wehrle-Haller to characterize the strength of cell-matrix adhesion and how it is modulated by the glycocalyx [5], while Chirasatitsin and Engler use force spectroscopy mapping to characterize the spatial distribution of adhesive sites on the substrate [6]. Scrimgeour et al describe a new method to adhesively pattern self-assembled monolayers for cell adhesion by a simple photobleaching setup [7] and Stricker et al demonstrate how elastic substrates can be combined with microcontact printing to improve the reconstruction of traction forces [8]. The work by Metzner et al shows that meaningful results on the cell-substrate interactions can be extracted also from experiments in which cells interact with biofunctionalized beads [9]. If cells start to adhere to a substrate, the main rate-limiting step is establishment of close contact between the plasma membrane and the substrate. This process can be followed with high spatial and temporal resolution with reflection interference microscopy, as demonstrated by Ryzhkov et al for mouse embryonic fibroblasts [10] and by Cretel et al for T lymphocytes [11]. Once mature adhesion has been achieved, the integrin-based focal adhesions providing anchorage to the substrate are strongly connected to the actin cytoskeleton, the main determinant of cell shape and structure. Heil and Spatz use microfabricated pillars to perturb the mechanical balance and quantitatively characterize the fast response of the focal adhesions [12]. A similar approach is used by Kirchenbüchler et al, who use deformation of an elastic substrate to demonstrate that the weak link in the mechanical system of substrate, adhesions and actin cytoskeleton is most likely located at the adhesion-cytoskeleton interface [13]. Rather than using external perturbations, Zemel et al quantify and model how cells spontaneously polarize their cytoskeleton in response to the physical properties of the substrate [14]. Quantitative analysis of cellular data has become standard in the field of cell-substrate interactions. Moreover, theoretical models for cell-substrate interactions help us to identify and understand the mechanisms underlying the observed phenomena in these complex systems. Recently, a large effort has been invested into understanding how force transmitted by the actin cytoskeleton changes the state of focal adhesions. In the contribution by Biton and Safran, this issue is addressed for the case that force arises from shear flow over an adhering cell [15]. Another important source for force on focal adhesions is actin retrograde flow, which has been demonstrated before to show variable coupling to the underlying layer of adhesion receptors. Two contributions discuss how stochastic bond dynamics at the cell-substrate interface is modulated by physical factors. The model by Sabass and Schwarz suggests that dissipation in the actin cytoskeleton stabilizes bond dynamics [16] and the model by Li et al suggests that catch bonding and multiple layers are important elements of the way focal adhesions function [17]. If interacting with an elastic environment, the combined system of focal adhesions and actin cytoskeleton can be used by cells to sense its rigidity and to make decisions on its response. Moshayedi et al show that great care has to be taken when preparing soft elastic substrates for cell culture studies and then use their protocols to quantitatively evaluate the mechanosensitive response of astrocytes from the brain [18]. The cellular system used by Lee et al is pericytes from the microvasculature, for which the authors show that they exert sufficient forces to stimulate vascular endothelial cells [19]. Buxboim et al use the technology of soft elastic substrates to measure how far mesenchymal stem cells can mechanically sense into their substrate [20]. The mechanical activity of cells observed in two-dimensional cell culture has significant consequences for both physiological and disease-related situations, including cell migration, tissue maintenance and tumor growth. Jannat et al show that chemotaxis of neutrophils, that is the first line of the immune 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 cytoskeleton-bound microbeads—the effect of bead-receptor binding dynamics J. Phys.: Condens. Matter 22 194105 [10] Ryzhkov P, Prass M, Gummich M, Kühn J-S, Oettmeier C and Döbereiner H-G 2010 Adhesion patterns in early cell spreading J. Phys.: Condens. Matter 22 194106 [11] Cretel E, Touchard D, Benoliel A M, Bongrand P and Pierres A 2010 Early contacts between T lymphocytes and activating surfaces J. Phys.: Condens. Matter 22 194107 [12] Heil P and Spatz J P 2010 Lateral shear forces applied to cells with single elastic micropillars to influence focal adhesion dynamics J. Phys.: Condens. Matter 22 194108 [13] Kirchenbüchler D, Born S, Kirchgeßner N, Houben S, Hoffmann B and Merkel R 2010 Substrate, focal adhesions, and actin filaments: a mechanical unit with a weak spot for mechanosensitive proteins J. Phys.: Condens. Matter 22 194109 [14] Zemel A, Rehfeldt F, Brown A E X, Discher D E and Safran S A 2010 Cell shape, spreading symmetry, and the polarization of stress-fibers in cells J. Phys.: Condens. Matter 22 194110 [15] Biton Y Y and Safran S A 2010 Theory of the mechanical response of focal adhesions to shear flow J. Phys.: Condens. Matter 22 194111 [16] Sabass B and Schwarz U S 2010 Modeling cytoskeletal flow over adhesion sites: competition between stochastic bond dynamics and intracellular relaxation J. Phys.: Condens. Matter 22 194112 [17] Li Y, Bhimalapuram P and Dinner A R 2010 Model for how retrograde actin flow regulates adhesion traction stresses J. Phys.: Condens. Matter 22 194113 [18] Moshayedi P, da F Costa L, Christ A, Lacour S P, Fawcett J, Guck J and Franze K 2010 Mechanosensitivity of astrocytes on optimized polyacrylamide gels analyzed by quantitative morphometry J. Phys.: Condens. Matter 22 194114 [19] Lee S, Zeiger A, Maloney J M, Kotecki M, Van Vliet K J and Herman I M 2010 Pericyte contraction at the cell-material interface can modulate the microvascular niche J. Phys.: Condens. Matter 22 194115 [20] Buxboim A, Rajagopal K, Brown A E X and Discher D E 2010 How deeply cells feel: methods for thin gels J. Phys.: Condens. Matter 22 194116 [21] Jannat R A, Robbins G P, Ricart B G, Dembo M and Hammer D A 2010 Neutrophil adhesion and chemotaxis depend on substrate mechanics J. Phys.: Condens. Matter 22 194117 [22] Mogilner A and Rubinstein B 2010 Actin disassembly 'clock' and membrane tension determine cell shape and turning: a mathematical method J. Phys.: Condens. Matter 22 194118 [23] Saez A, Anon E, Ghibaudo M, du Roure O, Di Meglio J-M, Hersen P, Silberzan P, Buguin A, Ladoux B 2010 Traction forces exerted by epithelial cell sheets J. Phys.: Condens. Matter 22 194119 [24] Levental I, Levental K R, Klein E A, Assoian R, Miller R T, Wells R G and Janmey P A 2010 A simple indentation device for measuring micrometer-scale tissue stiffness J. Phys.: Condens. Matter 22 194120 [25] Kotlarchyk M A, Botvinick E L and Putnam A J 2010 Characterization of hydrogel microstructure using laser tweezers particle tracking and confocal reflection imaging J. Phys.: Condens. Matter 22 194121 [26] Narayanan H, Verner S N, Mills K L, Kemkemer R and Garikipati K 2010 In silico estimates of the free energy rates in growing tumor spheroids J. Phys.: Condens. Matter 22 194122

EDITORIAL: Strongly correlated electron systems Strongly correlated electron systems

NASA Astrophysics Data System (ADS)

Ronning, Filip; Batista, Cristian

2011-03-01

Strongly correlated electrons is an exciting and diverse field in condensed matter physics. This special issue aims to capture some of that excitement and recent developments in the field. Given that this issue was inspired by the 2010 International Conference on Strongly Correlated Electron Systems (SCES 2010), we briefly give some history in order to place this issue in context. The 2010 International Conference on Strongly Correlated Electron Systems was held in Santa Fe, New Mexico, a reunion of sorts from the 1989 International Conference on the Physics of Highly Correlated Electron Systems that also convened in Santa Fe. SCES 2010—co-chaired by John Sarrao and Joe Thompson—followed the tradition of earlier conferences, in this century, hosted by Buzios (2008), Houston (2007), Vienna (2005), Karlsruhe (2004), Krakow (2002) and Ann Arbor (2001). Every three years since 1997, SCES has joined the International Conference on Magnetism (ICM), held in Recife (2000), Rome (2003), Kyoto (2006) and Karlsruhe (2009). Like its predecessors, SCES 2010 topics included strongly correlated f- and d-electron systems, heavy-fermion behaviors, quantum-phase transitions, non-Fermi liquid phenomena, unconventional superconductivity, and emergent states that arise from electronic correlations. Recent developments from studies of quantum magnetism and cold atoms complemented the traditional subjects and were included in SCES 2010. 2010 celebrated the 400th anniversary of Santa Fe as well as the birth of astronomy. So what's the connection to SCES? The Dutch invention of the first practical telescope and its use by Galileo in 1610 and subsequent years overturned dogma that the sun revolved about the earth. This revolutionary, and at the time heretical, conclusion required innovative combinations of new instrumentation, observation and mathematics. These same combinations are just as important 400 years later and are the foundation of scientific discoveries that were discussed during SCES 2010. As we learned, past dogmas about strongly correlated materials and phenomena must be re-examined with an open and inquisitive mind. Invited speakers and respected leaders in the field were invited to contribute to this special issue and we have insisted that they present new data, ideas, or perspectives, as opposed to simply an overview of their past work. As with the conference, this special issue touches upon recent developments of strongly correlated electron systems in d-electron materials, such as Sr3Ru2O7, graphene, and the new Fe-based superconductors, but it is dominated by topics in f-electron compounds. Contributions reflect the growing appreciation for the influence of disorder and frustration, the need for organizing principles, as well as detailed investigations on particular materials of interest and, of course, new materials. As this special issue could not possibly capture the full breadth and depth that the conference had to offer, it is being published simultaneously with an issue of Journal of Physics: Conference Series containing 157 manuscripts in which all poster presenters at SCES 2010 were invited to contribute. Since this special issue grew out of the 2010 SCES conference, we take this opportunity to give thanks. This conference would not have been possible without the hard work of the SCES 2010 Program Committee, International and National Advisory Committees, Local Committee, and conference organizers, the New Mexico Consortium. We thank them as well as those organizations that generously provided financial support: ICAM-I2CAM, Quantum Design, Lakeshore, the National High Magnetic Field Laboratory and the Department of Energy National Laboratories at Argonne, Berkeley, Brookhaven, Los Alamos and Oak Ridge. Of course, we especially thank the participants for bringing new ideas and new results, without which SCES 2010 would not have been possible. Strongly correlated electron systems contents Spin-orbit coupling and k-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 Wirth, Cornelius Krellner, Christoph Geibel, Frank Steglich, Silke Paschen, Stefan Kirchner and Qimiao Si Roles of critical valence fluctuations in Ce- and Yb-based heavy fermion metals Shinji Watanabe and Kazumasa Miyake Unconventional quantum criticality in the pressure-induced heavy-fermion superconductor CeRhIn5 Tuson Park, V A Sidorov, H Lee, F Ronning, E D Bauer, J L Sarrao and J D Thompson Magnetic structure of the antiferromagnetic Fulde-Ferrell-Larkin-Ovchinnikov state Youichi Yanase and Manfred Sigrist Magnetic transition and spin fluctuations in the unconventional antiferromagnetic compound Yb3Pt4 S Zhao, D E MacLaughlin, O O Bernal, J M Mackie, C Marques, Y Janssen and M C Aronson The non-centrosymmetric heavy fermion ferromagnet Sm2Fe12P7 M Janoschek, R E Baumbach, J J Hamlin, I K Lum and M B Maple Magnetic, thermal, and transport properties of the actinide based noncentrosymmetric compounds Th2Fe12P7 and U2Fe12P7 R E Baumbach, J J Hamlin, M Janoschek, I K Lum and M B Maple Magnetic order in Pu2M3Si5 (M = Co, Ni) E D Bauer, P H Tobash, J N Mitchell, J A Kennison, F Ronning, B L Scott and J D Thompson

EDITORIAL: Colloidal suspensions Colloidal suspensions

NASA Astrophysics Data System (ADS)

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

2011-05-01

Special issue in honour of Henk Lekkerkerker's 65th birthday Professor Henk N W Lekkerkerker is a world-leading authority in the field of experimental and theoretical soft condensed matter. On the occasion of his 65th birthday in the summer of 2011, this special issue celebrates his many contributions to science. Henk Lekkerkerker obtained his undergraduate degree in chemistry at the University of Utrecht (1968) and moved to Calgary where he received his PhD in 1971. He moved to Brussels as a NATO fellow at the Université Libre de Bruxelles and was appointed to an assistant professorship (1974), an associate professorship (1977) and a full professorship (1980) in physical chemistry at the Vrije Universiteit Brussel. In 1985 he returned to The Netherlands to take up a professorship at the Van 't Hoff Laboratory, where he has been ever since. He has received a series of awards during his career, including the Onsager Medal (1999) of the University of Trondheim, the Bakhuys Roozeboom Gold Medal (2003) of the Royal Dutch Academy of Arts and Sciences (KNAW), the ECIS-Rhodia European Colloid and Interface Prize (2003), and the Liquid Matter Prize of the European Physical Society (2008). He was elected a member of KNAW in 1996, was awarded an Academy Chair position in 2005, and has held several visiting lectureships. Henk's work focuses on phase transitions in soft condensed matter, and he has made seminal contributions to both the theoretical and experimental aspects of this field. Here we highlight three major themes running through his work, and a few selected publications. So-called depletion interactions may lead to phase separation in colloid-polymer mixtures, and Henk realised that the partitioning of polymer needs to be taken into account to describe the phase behaviour correctly [1]. Colloidal suspensions can be used as model fluids, with the time- and length-scales involved leading to novel opportunities, notably the direct observation of capillary waves at a fluid-fluid interface [2]. Together with Remco Tuinier, Henk has recently completed a book in this area which is to appear later this year. A major theme in Henk's research is that of phase transitions in lyotropic liquid crystals. Henk, together with Daan Frenkel and Alain Stroobants, realized in the 1980s that a smectic phase in dispersions of rod-like particles can be stable without the presence of attractive interactions, similar to nematic ordering as predicted earlier by Onsager [3]. Together with Gert-Jan Vroege he wrote a seminal review in this area [4]. Henk once said that 'one can only truly develop one colloidal model system in one's career' and in his case this must be that of gibbsite platelets. Initially Henk's group pursued another polymorph of aluminium hydroxide, boehmite, which forms rod-like particles [5], which already displayed nematic liquid crystal phases. The real breakthrough came when the same precursors treated the produced gibbsite platelets slightly differently. These reliably form a discotic nematic phase [6] and, despite the polydispersity in their diameter, a columnar phase [7]. A theme encompassing a wide range of soft matter systems is that of colloidal dynamics and phase transition kinetics. Many colloidal systems have a tendency to get stuck in metastable states, such as gels or glasses. This is a nuisance if one wishes to study phase transitions, but it is of great practical significance. Such issues feature in many of Henk's publications, and with Valerie Anderson he wrote a highly cited review in this area [8]. Henk Lekkerkerker has also invested significant effort into the promotion of synchrotron radiation studies of colloidal suspensions. He was one of the great supporters of the Dutch-Belgian beamline 'DUBBLE' project at the ESRF [9]. He attended one of the very first experiments in Grenoble in 1999, which led to a Nature publication [7]. He was strongly involved in many other experiments which followed and also has been a member of the beam line board. The most recent synchotron data are reported in this issue and Henk is a co-author on the paper. Henk's international leadership in the soft condensed matter field is also illustrated by some of the various roles he has held over the years, such as that of president of the European Colloid and Interface Society 1995-6. He was the heart and soul of the 6th Liquid Matter Conference in Utrecht (2005). For many years he acted as consultant to Schlumberger Cambridge Research. Henk is a towering figure in the scientific community, not just physically but in particular through his intellectual rigour. Henk also took on administrative roles, notably as dean of the chemistry department in Utrecht University and as scientific director of the Debye Institute, and he did these tasks thoroughly and effectively. Henk is an inspiring teacher and his lectures and notes are always of outstanding clarity. Henk has supervised a series of PhD students and postdoctoral researchers, several of whom have taken up academic positions since. A particular strength of Henk is his phenomenal command of the scientific literature which translates into authoritative introductions to his publications. For example, one of us once came to him saying that he had calculated the scattering profiles for a simple one-dimensional model, which can be applied to describe intra-columnar scattering from a columnar phase of gibbsite platelets. After seeing what the model assumptions were, Henk immediately opened his drawer and quickly found a paper of Zernike and Prins dated 1927 [10]. 'Is this the model you are talking about?' he asked. Of course it was. This was a great lesson, which not only demonstrated Henk's familiarity with the literature but also the effectiveness of his filing system. A favourite tool of Henk's trade is that of the (mostly handwritten) 'notities' (notes) he would hand or send to his students and collaborators to feed scientific discussions. We have been the grateful recipients of many such notes ourselves. Visitors to Henk's office would often be treated to a demonstration experiment (for instance, birefringent suspensions) and a range of hand-made models designed to illustrate complex concepts (such as multidimensional phase diagrams). Henk's relationship with his students usually extends well after graduation, and many have benefitted from Henk's advice as a mentor. In spite of his scientific standing, Henk is down to earth; he is a pleasant and warm person, with a deep interest in people. He has many friends all over the world. At the same time, he does not eschew scientific debate. He takes a dim view of pretentious work, especially when it seems that inconvenient data has been neglected. Typically though he will comment in a way that avoids embarrassment and that motivates a redoubled effort. Henk's career will be celebrated at a symposium to be held in Amsterdam in June 2011. This special issue contains invited contributions by speakers at this symposium, as well as by other collaborators, colleagues, former students, and friends. The authors were free to choose their topics. We have grouped their contributions into a number of themes. The wide range of subjects mirrors Henk's interests and the research themes reviewed above are well represented. Henk, this special issue is for you—we hope you will enjoy it! References [1] Lekkerkerker H N W, Poon W C-K, Pusey P N, Stroobants A and Warren P B 1992 Europhys. Lett. 20 559 [2] Aarts D G A L, Schmidt M and Lekkerkerker H N W 2004 Science 304 847 [3] Frenkel D, Lekkerkerker H N W and Stroobants A 1988 Nature 332 822 [4] Vroege G J and Lekkerkerker H N W 1992 Rep. Prog. Phys. 55 1241 [5] Buining P A, Pathmamanoharan C, Jansen J B H and Lekkerkerker H N W 1991 J. Am. Ceram. Soc. 74 1303 [6] van der Kooij F M and Lekkerkerker H N W 1998 J. Phys. Chem. B 102 7829 [7] van der Kooij F M, Kassapidou K and Lekkerkerker H N W 2000 Nature 406 868 [8] Anderson V J and Lekkerkerker H N W 2002 Nature 416 811 [9] Borsboom M et al 1998 J. Synchrotron Radiat. 5 518 [10] Zernike F and Prins J A 1927 Z. Phys. 41 184 Colloidal suspensions contents How much does the core structure of a three-phase contact line contribute to the line tension near a wetting transition? J O Indekeu, K Koga and B Widom A systematic coarse-graining strategy for semi-dilute copolymer solutions: from monomers to micelles Barbara Capone, Ivan Coluzza and Jean-Pierre Hansen Structural searches using isopointal sets as generators: densest packings for binary hard sphere mixtures Toby S Hudson and Peter Harrowell The theory of delamination during drying of confined colloidal suspensions K J Wallenstein and W B Russel Electrostatics Modeling of equilibrium hollow objects stabilized by electrostatics Ethayaraja Mani, Jan Groenewold and Willem K Kegel The Donnan equilibrium: I. On the thermodynamic foundation of the Donnan equation of state A Philipse and A Vrij Colloidal rods and platelets Cholesteric order in systems of helical Yukawa rods H H Wensink and G Jackson Magnetic-field-induced nematic-nematic phase separation and droplet formation in colloidal goethite E van den Pol, A A Verhoeff, A Lupascu, M A Diaconeasa, P Davidson, I Dozov, B W M Kuipers, D M E Thies-Weesie and G J Vroege Structure of colloidal sphere-plate mixtures N Doshi, G Cinacchi, J S van Duijneveldt, T Cosgrove, S W Prescott, I Grillo, J Phipps and D I Gittins 3D structure of nematic and columnar phases of hard colloidal platelets A B G M Leferink op Reinink, J M Meijer, D Kleshchanok, D V Byelov, G J Vroege, A V Petukhov and H N W Lekkerkerker Phase behaviour of binary mixtures of diamagnetic colloidal platelets in an external magnetic field Jonathan Phillips and Matthias Schmidt Rheo-SAXS investigation of shear-thinning behaviour of very anisometric repulsive disc-like clay suspensions A M Philippe, C Baravian, M Imperor-Clerc, J De Silva, E Paineau, I Bihannic, P Davidson, F Meneau, P Levitz and L J Michot 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