Sample records for magnetic compass orientation

  1. Orientation of churches by magnetic compasses?

    NASA Astrophysics Data System (ADS)

    Arneitz, Patrick; Draxler, Andrea; Rauch, Roman; Leonhardt, Roman

    2014-07-01

    In Christian religion the sunrise is of great symbolic importance. Therefore, many churches constructed in the Middle Ages point towards geographic East. Although `easting' of churches actually refers to the alignment towards the azimuth of sunrise on the individual churches' patron's day, deviation of nave alignment from the geographic East direction is often assumed to be caused by the use of magnetic compasses. Therefore, the church alignment could provide information about historical magnetic declination. We investigate 124 churches in Lower Austria and 68 in northern Germany to clarify this question as well as the `easting' hypothesis. Church orientations are determined from georeferenced satellite images. Metadata such as the construction year, possible reconstructions and the church patron are gathered to determine the date when current church direction was appointed, and to perform sunrise calculations. However, due to uncertainties of construction years and the declining importance of orientation tradition after the 15th century several churches are excluded from the study. Thus, 32 churches with reliable metadata remain for evaluation in each region. The analysis reveals a preferred alignment of naves towards geographic East in Lower Austria and northern Germany. The construction and alignment of churches was often affected by the pre-existing buildings and streets or topography and natural surroundings. Therefore, deviations from geographic East are more likely caused by town or landscape. The mean deviations from magnetic East in both regions are large compared to the mean deviations from geographic East and sunrise azimuths. Hence, the use of compasses cannot be confirmed. Despite a few churches indicating orientation according to their patron's day, a general trend cannot be observed in the data reviewed.

  2. The effect of yellow and blue light on magnetic compass orientation in European robins, Erithacus rubecula

    Microsoft Academic Search

    W. Wiltschko; R. Wiltschko

    1999-01-01

    To analyze the wavelength dependency of magnetic compass orientation, European robins were tested during spring migration\\u000a under light of various wavelengths. Under 565-nm green light (control) the birds showed excellent orientation in their migratory\\u000a direction; a 120° deflection of magnetic North resulted in a corresponding shift in the birds' directional tendencies, indicating\\u000a the use of the magnetic compass. Under 443-nm

  3. Wavelength-dependent effects of light on magnetic compass orientation in Drosophila melanogaster

    Microsoft Academic Search

    J. B. Phillips; O. Sayeed

    1993-01-01

    1.Wildtype Oregon-R Drosophila melanogaster were trained in the ambient magnetic field to a horizontal gradient of 365 nm light emanating from one of the 4 cardinal compass directions and were subsequently tested in a visually-symmetrical, radial 8-arm maze in which the magnetic field alignment could be varied. When tested under 365 nm light, flies exhibited consistent magnetic compass orientation in

  4. Magnetic compass orientation in birds and its physiological basis

    Microsoft Academic Search

    Wolfgang Wiltschko; Roswitha Wiltschko

    2002-01-01

    A current model suggests that magnetoreception of compass information starts with light-dependent primary processes. Light-dependency of magnetoreception is supported by behavioral experiments with homing pigeons and caged migratory birds. Three passerine species showed normal orientation under dim monochromatic light from the blue-green range of the spectrum, while they were disoriented under yellow and red light. A sevenfold increase in intensity

  5. Spontaneous expression of magnetic compass orientation in an epigeic rodent: the bank vole, Clethrionomys glareolus.

    PubMed

    Oliveriusová, Ludmila; N?mec, Pavel; Pavelková, Zuzana; Sedlá?ek, František

    2014-07-01

    Magnetoreception has been convincingly demonstrated in only a few mammalian species. Among rodents, magnetic compass orientation has been documented in four species of subterranean mole rats and two epigeic (i.e. active above ground) species-the Siberian hamster and the C57BL/6J mouse. The mole rats use the magnetic field azimuth to determine compass heading; their directional preference is spontaneous and unimodal, and their magnetic compass is magnetite-mediated. By contrast, the primary component of orientation response is learned in the hamster and the mouse, but both species also exhibit a weak spontaneous bimodal preference in the natural magnetic field. To determine whether the magnetic compass of wild epigeic rodents features the same functional properties as that of laboratory rodents, we investigated magnetic compass orientation in the bank vole Clethrionomys glareolus (Cricetidae, Rodentia). The voles exhibited a robust spontaneous bimodal directional preference, i.e. built nests and slept preferentially along the north-south axis, and deflected their directional preference according to a shift in the direction of magnetic north, clearly indicating that they were deriving directional information from the magnetic field. Thus, bimodal, axially symmetrical directional choice seems to be a common feature shared by epigeic rodents. However, spontaneous directional preference in the bank vole appeared to be more pronounced than that reported in the hamster and the mouse. These findings suggest that bank voles are well suited for future studies investigating the adaptive significance and mechanisms of magnetic orientation in epigeic rodents. PMID:24913128

  6. Spontaneous expression of magnetic compass orientation in an epigeic rodent: the bank vole, Clethrionomys glareolus

    NASA Astrophysics Data System (ADS)

    Oliveriusová, Ludmila; N?mec, Pavel; Pavelková, Zuzana; Sedlá?ek, František

    2014-07-01

    Magnetoreception has been convincingly demonstrated in only a few mammalian species. Among rodents, magnetic compass orientation has been documented in four species of subterranean mole rats and two epigeic (i.e. active above ground) species—the Siberian hamster and the C57BL/6J mouse. The mole rats use the magnetic field azimuth to determine compass heading; their directional preference is spontaneous and unimodal, and their magnetic compass is magnetite-mediated. By contrast, the primary component of orientation response is learned in the hamster and the mouse, but both species also exhibit a weak spontaneous bimodal preference in the natural magnetic field. To determine whether the magnetic compass of wild epigeic rodents features the same functional properties as that of laboratory rodents, we investigated magnetic compass orientation in the bank vole Clethrionomys glareolus (Cricetidae, Rodentia). The voles exhibited a robust spontaneous bimodal directional preference, i.e. built nests and slept preferentially along the north-south axis, and deflected their directional preference according to a shift in the direction of magnetic north, clearly indicating that they were deriving directional information from the magnetic field. Thus, bimodal, axially symmetrical directional choice seems to be a common feature shared by epigeic rodents. However, spontaneous directional preference in the bank vole appeared to be more pronounced than that reported in the hamster and the mouse. These findings suggest that bank voles are well suited for future studies investigating the adaptive significance and mechanisms of magnetic orientation in epigeic rodents.

  7. Use of a Magnetic Compass for Nocturnal Homing Orientation in the Palmate Newt, Lissotriton helveticus

    E-print Network

    Phillips, John B.

    Use of a Magnetic Compass for Nocturnal Homing Orientation in the Palmate Newt, Lissotriton, Virginia Tech, Blacksburg, Virginia, USA Introduction Newts have proved to be an excellent model sys- tem ponds (Freake et al. 2006), make newts an excellent model for compari- son with vertebrates that home

  8. Migration, Orientation and Navigation: Magnetic Compasses in Insects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The use of magnetic information for orientation and navigation is a widespread phenomenon in animals. In contrast to navigational systems in vertebrates, our understanding of the mechanisms underlying the insect magnetic perception and use of the information is at an early stage. Some insects use ma...

  9. Anthropogenic electromagnetic noise disrupts magnetic compass orientation in a migratory bird.

    PubMed

    Engels, Svenja; Schneider, Nils-Lasse; Lefeldt, Nele; Hein, Christine Maira; Zapka, Manuela; Michalik, Andreas; Elbers, Dana; Kittel, Achim; Hore, P J; Mouritsen, Henrik

    2014-05-15

    Electromagnetic noise is emitted everywhere humans use electronic devices. For decades, it has been hotly debated whether man-made electric and magnetic fields affect biological processes, including human health. So far, no putative effect of anthropogenic electromagnetic noise at intensities below the guidelines adopted by the World Health Organization has withstood the test of independent replication under truly blinded experimental conditions. No effect has therefore been widely accepted as scientifically proven. Here we show that migratory birds are unable to use their magnetic compass in the presence of urban electromagnetic noise. When European robins, Erithacus rubecula, were exposed to the background electromagnetic noise present in unscreened wooden huts at the University of Oldenburg campus, they could not orient using their magnetic compass. Their magnetic orientation capabilities reappeared in electrically grounded, aluminium-screened huts, which attenuated electromagnetic noise in the frequency range from 50?kHz to 5?MHz by approximately two orders of magnitude. When the grounding was removed or when broadband electromagnetic noise was deliberately generated inside the screened and grounded huts, the birds again lost their magnetic orientation capabilities. The disruptive effect of radiofrequency electromagnetic fields is not confined to a narrow frequency band and birds tested far from sources of electromagnetic noise required no screening to orient with their magnetic compass. These fully double-blinded tests document a reproducible effect of anthropogenic electromagnetic noise on the behaviour of an intact vertebrate. PMID:24805233

  10. Orientations Of Minoan Buildings On Crete May Indicate The First Recorded Use Of The Magnetic Compass

    NASA Astrophysics Data System (ADS)

    Downey, W. S.

    Archaeomagnetic research has enabled the determination of the secular variation record of the past geomagnetic field and has been used as a tool for absolute and relative dating. The archaeomagnetic secular variation of declination can be used in conjunction with architectural building plan orientation angles (strike directions) to establish, whether or not, a magnetic compass was possibly used to align buildings. Until now, it has been speculative as to, how or why, Minoan buildings were orientated in an approximate North-South direction or at 'askew' angles to one another. Here, it is observed, that, the orientation angles, of some significant Minoan buildings on Crete which have been compared to the archaeomagnetic (secular variation of declination) reference curve record (Bulgaria) for that period, are consistent with the possible use of a magnetic compass. Four of the six main Palaces and other significant buildings may have been oriented using this method. This may indicate the first recorded use, by the Minoans of a magnetic compass. These findings have archaeological implications (chronology) and are of significant interest architecturally. They are also relevant to Minoan religious and cult studies and may have implications for Minoan maritime navigation studies.

  11. Migrating Songbirds Recalibrate Their Magnetic Compass Daily

    E-print Network

    Murphy, Troy G.

    Migrating Songbirds Recalibrate Their Magnetic Compass Daily from Twilight Cues William W. Cochran, the same individuals migrated northward again. We suggest that birds orient with a magnetic compass­3) after a voyage of up to 25,000 km (4, 5). Migratory songbirds can orient on the basis of compass

  12. Magnetic Compass Orientation in the European Eel Caroline M. F. Durif , Howard I. Browman, John B. Phillips, Anne Berit Skiftesvik, L. Asbjrn Vllestad, Hans H. Stockhausen

    E-print Network

    Phillips, John B.

    Magnetic Compass Orientation in the European Eel Caroline M. F. Durif , Howard I. Browman, John B. Phillips, Anne Berit Skiftesvik, L. Asbjørn Vøllestad, Hans H. Stockhausen Abstract European eel migrate magnetic compass orientation in earth-strength magnetic field intensities. We tested eels in four altered

  13. Magnetic compass orientation is well established in night-migrating songbirds (for example reviews, see Wiltschko and

    E-print Network

    Anderson, David J.

    Magnetic compass orientation is well established in night- migrating songbirds (for example reviews hypotheses have been proposed, and both are supported by some experimental evidence. Magnetic fields may of the bird (Leask, 1977; Ritz et al., 2000; Wiltschko et al., 2002) and/or magnetic fields may be sensed via

  14. Magnetic Spinner & Compass

    NSDL National Science Digital Library

    Watsonville Environmental Science Workshop

    2011-01-01

    Learners use shop tools and various materials to construct a magnetic spinner and a compass. Learners blow on the spinner directly or through a straw, and will be amazed as it continues to spin, appearing as if it's levitating. Learners can also use the compass to follow or take a bearing. Use this activity to introduce learners to magnets, magnetic fields, friction, and magnetic levitation.

  15. A magnetic compass aids monarch butterfly migration

    PubMed Central

    Guerra, Patrick A; Gegear, Robert J; Reppert, Steven M

    2014-01-01

    Convincing evidence that migrant monarch butterflies (Danaus plexippus) use a magnetic compass to aid their fall migration has been lacking from the spectacular navigational capabilities of this species. Here we use flight simulator studies to show that migrants indeed possess an inclination magnetic compass to help direct their flight equatorward in the fall. The use of this inclination compass is light-dependent utilizing ultraviolet-A/blue light between 380 and 420?nm. Notably, the significance of light <420?nm for inclination compass function was not considered in previous monarch studies. The antennae are important for the inclination compass because they appear to contain light-sensitive magnetosensors. For migratory monarchs, the inclination compass may serve as an important orientation mechanism when directional daylight cues are unavailable and may also augment time-compensated sun compass orientation for appropriate directionality throughout the migration. PMID:24960099

  16. A magnetic compass aids monarch butterfly migration.

    PubMed

    Guerra, Patrick A; Gegear, Robert J; Reppert, Steven M

    2014-01-01

    Convincing evidence that migrant monarch butterflies (Danaus plexippus) use a magnetic compass to aid their fall migration has been lacking from the spectacular navigational capabilities of this species. Here we use flight simulator studies to show that migrants indeed possess an inclination magnetic compass to help direct their flight equatorward in the fall. The use of this inclination compass is light-dependent utilizing ultraviolet-A/blue light between 380 and 420?nm. Notably, the significance of light <420?nm for inclination compass function was not considered in previous monarch studies. The antennae are important for the inclination compass because they appear to contain light-sensitive magnetosensors. For migratory monarchs, the inclination compass may serve as an important orientation mechanism when directional daylight cues are unavailable and may also augment time-compensated sun compass orientation for appropriate directionality throughout the migration. PMID:24960099

  17. Compasses

    NSDL National Science Digital Library

    Brieske, Joel A.

    2003-01-01

    This Topic in Depth explores the Web's offering on compasses. The first site is another great site from How Stuff Works.com called How Compasses Work (1). Visitors can read the interesting text and view attractive graphics on the basics of what a compass is and how it is used. The second site, maintained by Learn-Orienteering.com, is specifically about How to Use a Compass (2). Topics covered include the Compass Alone, Compass and Map Interacting, Magnetic Declination and Uncertainty, Suggested Exercises, Navigating Under Difficult Conditions, Finding the Directions Without a Compass, A Collection of Rhymes People use to Remember About Declination, and even information and tips on Buying a Compass. From Heather Williams of Williams College comes the next site entitled Compass Types (3 ). Here, those interested can learn about the workings, uses, and differences of the baseplate or protractor compass and the thumb compass. One other interesting paragraph describes how important the compass actually is for navigation. The fourth site is a quality lesson plan offered by National Geographic's Xpeditioin Web site called Which Direction Should I Go (4)? The activity "has students review and practice their knowledge of compass directions and do several brief exercises to practice using directions in their community and on maps." Next, the Make a Compass (5) Web site is part of the Federal Aviation Administration's Aviation Education page. Visitors learn how to make a simple compass out a sewing needle, magnet, bowl of water, and a piece of paper, pretty easily. The history of magnetism and the compass is chronicled in the next site from NASA called Magnetic Fields: History (6). The site explains what transpired when Hans Christian Oersted in 1820 carried out demonstrations of magnetism using a compass needle mounted on a wooden stand. The seventh site is part of Opticsgiant.com, an optics retailer, called Compasses (7). The site provides a short description on how to use a compass, but was primarily chosen to give readers an idea of the wide range of compasses that are available today for purchase. The last site on this subject is maintained by the US Geological Survey called Finding Your Way with Map and Compass (5). This well designed site does a good job of explaining everything from using topographic maps, determining direction, taking a compass bearing, and more.

  18. Interrelation of magnetic compass and star orientation in night-migrating birds

    Microsoft Academic Search

    Wolfgang Wiltschko; Roswitha Wiltschko

    1976-01-01

    To test the orientation model that the stars derive their directional significance from the magnetic field, the orientation of European Robins (Erithacus rubecula) to an arbitrary pattern of 16 “stars” (Fig. 1) was examined.

  19. Magnetic compass orientation in the Eastern red-spotted newt ( Notophthalmus viridescens )

    Microsoft Academic Search

    John B. Phillips

    1986-01-01

    Laboratory tests were carried out to examine the orientation behavior of adult Eastern red-spotted newts (Notophthalmus viridescens) to earth-strength magnetic fields. Groups of 30 to 40 newts were housed in water-filled, all-glass aquaria with an artificial shoreline at one end. The aquaria were located in a greenhouse or outdoors adjacent to the laboratory building, and aligned on either the magnetic

  20. Evidence for celestial and magnetic compass orientation in lake migrating sockeye salmon fry

    Microsoft Academic Search

    Thomas P. Quinn

    1980-01-01

    1.Radially symmetrical, four-armed tanks were designed for testing the directional preferences of sockeye salmon (Oncorhynchus nerka) fry as they commenced up-lake migrations following emergence from gravel nests and river migration to the lake.2.When tested during the day or night, as appropriate for their migration, fry from two different stocks moved in compass directions corresponding to the directions which they would

  1. Magnetic Compass of European Robins

    Microsoft Academic Search

    Wolfgang Wiltschko; Roswitha Wiltschko

    1972-01-01

    The magnetic compass of European robins does not use the polarity of the magnetic field for detecting the north direction. The birds derive their north direction from interpreting the inclination of the axial direction of the magnetic field lines in space, and they take the direction on the magnetic north-south axis for \\

  2. Discovery of the Magnetic Compass

    NSDL National Science Digital Library

    Stern, David P. (David Peter), 1931-

    First of several linked files, telling the early history of the compass (discovered in China) and how Robert Norman in 1581 showed the magnetic force was not horizontal but slanted downwards, followed by William Gilbert's demonstration that the Earth behaved like a giant magnet; two reviews of Gilbert's 1600 book "De Magnete" follow, as well as a modern version of one of Gilbert's experiments. The web collection also includes several sections for science teachers. The page is a subset of a larger collection of articles of the history of magnetism created by author David P. Stern.

  3. 46 CFR 108.715 - Magnetic compass and gyrocompass.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Magnetic compass and gyrocompass. 108.715...Miscellaneous Equipment § 108.715 Magnetic compass and gyrocompass. (a) Each...ocean or coastwise service must have a magnetic compass. (b) Each...

  4. 46 CFR 167.40-45 - Magnetic compass and gyrocompass.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Magnetic compass and gyrocompass. 167.40-45...Equipment Requirements § 167.40-45 Magnetic compass and gyrocompass. (a...coastwise service must be fitted with a magnetic compass. (b) All...

  5. 46 CFR 108.715 - Magnetic compass and gyrocompass.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Magnetic compass and gyrocompass. 108.715...Miscellaneous Equipment § 108.715 Magnetic compass and gyrocompass. (a) Each...ocean or coastwise service must have a magnetic compass. (b) Each...

  6. Light-dependent magnetic compass in Iberian green frog tadpoles

    NASA Astrophysics Data System (ADS)

    Diego-Rasilla, Francisco Javier; Luengo, Rosa Milagros; Phillips, John B.

    2010-12-01

    Here, we provide evidence for a wavelength-dependent effect of light on magnetic compass orientation in Pelophylax perezi (order Anura), similar to that observed in Rana catesbeiana (order Anura) and Notophthalmus viridescens (order Urodela), and confirm for the first time in an anuran amphibian that a 90° shift in the direction of magnetic compass orientation under long-wavelength light (?500 nm) is due to a direct effect of light on the underlying magnetoreception mechanism. Although magnetic compass orientation in other animals (e.g., birds and some insects) has been shown to be influenced by the wavelength and/or intensity of light, these two amphibian orders are the only taxa for which there is direct evidence that the magnetic compass is light-dependent. The remarkable similarities in the light-dependent magnetic compasses of anurans and urodeles, which have evolved as separate clades for at least 250 million years, suggest that the light-dependent magnetoreception mechanism is likely to have evolved in the common ancestor of the Lissamphibia (Early Permian, ~294 million years) and, possibly, much earlier. Also, we discuss a number of similarities between the functional properties of the light-dependent magnetic compass in amphibians and blue light-dependent responses to magnetic stimuli in Drosophila melanogaster, which suggest that the wavelength-dependent 90° shift in amphibians may be due to light activation of different redox forms of a cryptochrome photopigment. Finally, we relate these findings to earlier studies showing that the pineal organ of newts is the site of the light-dependent magnetic compass and recent neurophysiological evidence showing magnetic field sensitivity in the frog frontal organ (an outgrowth of the pineal).

  7. Resonance effects indicate a radical-pair mechanism for avian magnetic compass

    Microsoft Academic Search

    Thorsten Ritz; Peter Thalau; John B. Phillips; Roswitha Wiltschko; Wolfgang Wiltschko

    2004-01-01

    Migratory birds are known to use the geomagnetic field as a source of compass information. There are two competing hypotheses for the primary process underlying the avian magnetic compass, one involving magnetite, the other a magnetically sensitive chemical reaction. Here we show that oscillating magnetic fields disrupt the magnetic orientation behaviour of migratory birds. Robins were disoriented when exposed to

  8. Orientation finding using a grid based visual compass

    E-print Network

    Visser, Arnoud

    Orientation finding using a grid based visual compass Georgios Methenitis Patrick M. de Kok Sander an extension of the model-based visual compass is presented, which can be updated contin- uously, allowing, a visual compass can be used [1, 4, 5]. Such a method estimates the robot's heading by comparing

  9. A magnetic compass sense has been demonstrated in a large and taxonomically diverse group of organisms. In terrestrial

    E-print Network

    Phillips, John B.

    A magnetic compass sense has been demonstrated in a large and taxonomically diverse group of organisms. In terrestrial organisms, magnetic orientation appears to be mediated by more than one type; Marhold et al., 1997). In contrast, magnetic compass orientation has been shown to be sensitive

  10. nCompass Service Oriented Architecture for Tacit Collaboration Services

    NASA Astrophysics Data System (ADS)

    Schroh, David; Bozowsky, Neil; Savigny, Mike; Wright, William

    nCompass is a flexible, Service Oriented Architecture (SOA) designed to support the research and deployment of advanced tacit collaboration technology services for analysts. nCompass allows a significantly larger number of individual analytic capabilities, applications and services to be integrated together quickly and effectively. Service integration results arc described from several computational tacit collaboration experiments conducted with open source intelligence analysts working with open source data. Key to nCompass is the technical framework and unique analytic event logging schema that supports context sharing across diverse applications and services. It is by combining the analyst with shared context across multiple advanced computational capabilities in a system of systems that a breakthrough in collaborative open source analysis can be achieved. This paper introduces the nCompass framework and integration platform, describes key nCompass core services, and provides results on functional synergies achieved through technology service integration with nCompass.

  11. 46 CFR 167.40-45 - Magnetic compass and gyrocompass.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Magnetic compass and gyrocompass. 167.40-45 Section...Requirements § 167.40-45 Magnetic compass and gyrocompass. (a) All mechanically...service must be fitted with a magnetic compass. (b) All mechanically...

  12. 46 CFR 108.715 - Magnetic compass and gyrocompass.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Magnetic compass and gyrocompass. 108.715 Section...Miscellaneous Equipment § 108.715 Magnetic compass and gyrocompass. (a) Each self-propelled...coastwise service must have a magnetic compass. (b) Each self-propelled...

  13. 46 CFR 167.40-45 - Magnetic compass and gyrocompass.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Magnetic compass and gyrocompass. 167.40-45 Section...Requirements § 167.40-45 Magnetic compass and gyrocompass. (a) All mechanically...service must be fitted with a magnetic compass. (b) All mechanically...

  14. 46 CFR 167.40-45 - Magnetic compass and gyrocompass.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Magnetic compass and gyrocompass. 167.40-45 Section...Requirements § 167.40-45 Magnetic compass and gyrocompass. (a) All mechanically...service must be fitted with a magnetic compass. (b) All mechanically...

  15. 46 CFR 108.715 - Magnetic compass and gyrocompass.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Magnetic compass and gyrocompass. 108.715 Section...Miscellaneous Equipment § 108.715 Magnetic compass and gyrocompass. (a) Each self-propelled...coastwise service must have a magnetic compass. (b) Each self-propelled...

  16. Calibration of the magnetic compass of a migratory bird by celestial rotation

    NASA Astrophysics Data System (ADS)

    Able, Kenneth P.; Able, Mary A.

    1990-09-01

    MIGRATORY birds use a variety of environmental stimuli in orientation. Species that migrate primarily at night can use compasses based on the geomagnetic field, stars, the Sun and patterns of skylight polarization1-4. These compass mechanisms can interact both when migratory birds make day-to-day orientation decisions5 and during their ontogeny in young birds6,7. All of the known compasses used by migratory birds seem to be modifiable by experience during early development. For example, a functional magnetic compass develops in birds that have never seen the sky8-11. But the preferred direction of orientation by the magnetic compass may be modified during the first three months of life by exposing naive birds to the sky under conditions in which magnetic directions differ substantially from compass directions indicated by the Sun and stars (true or geographic directions)6,9,10. For hand-raised Savannah sparrows (Passerculus sandwichensis), experience with either the clear daytime or night sky is sufficient to effect this calibration of the magnetic compass11. We therefore proposed that celestial rotation, which provides a source of geographic directions both day and night, is the calibrating reference. Here we report that the rotation of an artificial pattern of 'stars' calibrates the preferred direction of magnetic orientation of young Savannah sparrows.

  17. Do leaf-cutter ants Atta colombica orient their path-integrated, home vector with a magnetic compass?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leaf-cutter ants Atta colombica forage over 250 m in structurally-complex, Neotropical rainforests that occlude sun or polarized light cues. Night foraging makes the use of celestial cues and landmarks all the more difficult. We investigated the directional cues used by leaf-cutter ants to orient h...

  18. Tenebrio beetles use magnetic inclination compass

    NASA Astrophysics Data System (ADS)

    Vácha, Martin; Drštková, Dana; P?žová, Tereza

    2008-08-01

    Animals that guide directions of their locomotion or their migration routes by the lines of the geomagnetic field use either polarity or inclination compasses to determine the field polarity (the north or south direction). Distinguishing the two compass types is a guideline for estimation of the molecular principle of reception and has been achieved for a number of animal groups, with the exception of insects. A standard diagnostic method to distinguish a compass type is based on reversing the vertical component of the geomagnetic field, which leads to the opposite reactions of animals with two different compass types. In the present study, adults of the mealworm beetle Tenebrio molitor were tested by means of a two-step laboratory test of magnetoreception. Beetles that were initially trained to memorize the magnetic position of the light source preferred, during the subsequent test, this same direction, pursuant geomagnetic cues only. In the following step, the vertical component was reversed between the training and the test. The beetles significantly turned their preferred direction by 180°. Our results brought until then unknown original findings that insects, represented here by the T. molitor species, use—in contrast to another previously researched Arthropod, spiny lobster—the inclination compass.

  19. White-throated sparrows calibrate their magnetic compass by polarized light cues during both autumn and spring migration

    Microsoft Academic Search

    Rachel Muheim; John B. Phillips; Mark E. Deutschlander

    2009-01-01

    SUMMARY The interaction and hierarchy of celestial and magnetic compass cues used by migratory songbirds for orientation has long been the topic of an intense debate. We have previously shown that migratory Savannah sparrows, Passerculus sandwichensis, use polarized light cues near the horizon at sunrise and sunset to recalibrate their magnetic compass. Birds exposed to a ±90?deg. shifted artificial polarization

  20. Chinese tombs oriented by a compass: evidence from paleomagnetic declination changes versus tombs age

    NASA Astrophysics Data System (ADS)

    Charvatova, Ivanka; Klokocnik, Jaroslav; Kolmas, Josef; Kostelecky, Jan

    2010-05-01

    The use of the magnetic compass in China is documented at least since the Han dynasty (206 BC-220 AD), but may be older. Geomancy (fengshui) practicised for a long time had a profound influence on the face of China's landscape and city plans. The tombs (pyramids) near Xian (together with suburban fields and roads) have strange space orientations, sometimes in the basic south-north direction (with respect to the geographic pole), but ussually with deviations of several degrees to east or west. The use of the compass means that the needle is directed to the actual magnetic pole at the time of construction or last reconstruction of the given tomb. The magnetic pole however, relative to the 'fixed' geographic pole, wanders significantly in time. We successfully correlated (found a close trends), by using paleomagnetic data (for the central China and the time interval of interest), the starting date of pyramids building with respect to the magnetic pole position at that time. As in Mesoamerica, where according to Fuson hypothesis, the Olmecs and Maya oriented their ceremonial buildings and pyramids by compass even before the Chinese, here in central China the same technique may have been used. The agreeement of building alignments with likely magnetic pole positions at the time is fairly good. There are several written records that the knowledge of the various ancient types of compass in China is older than from the Han period but paleomagnetic declinations for China are generally so far not too precise.

  1. Value Orientation of Singapore Adolescents Towards Truthfulness, Justice and Compassion.

    ERIC Educational Resources Information Center

    Seng, SeokHoon; Siang, Low Meow; Wei, Tan Tai

    This study examined the value orientation of Singapore adolescents toward the three fundamental values of truthfulness, justice, and compassion. A random sample of 315 secondary school students from 4 schools in Singapore (135 males and 180 females) completed a questionnaire, and a select sample of 19 students completed interviews about their…

  2. Monarch butterflies (Danaus plexippus L.) use a magnetic compass for navigation

    PubMed Central

    Etheredge, Jason A.; Perez, Sandra M.; Taylor, Orley R.; Jander, Rudolf

    1999-01-01

    Fall migratory monarch butterflies, tested for their directional responses to magnetic cues under three conditions, amagnetic, normal, and reversed magnetic fields, showed three distinct patterns. In the absence of a magnetic field, monarchs lacked directionality as a group. In the normal magnetic field, monarchs oriented to the southwest with a group pattern typical for migrants. When the horizontal component of the magnetic field was reversed, the butterflies oriented to the northeast. In contrast, nonmigratory monarchs lacked directionality in the normal magnetic field. The results are a direct demonstration of magnetic compass orientation in migratory insects. PMID:10570160

  3. 20. View of magnetic compass; "bigeyes," used for surveying ships ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. View of magnetic compass; "bigeyes," used for surveying ships and shore; and signal lights (covered). - U.S. Coast Guard Cutter BRAMBLE, Waterfront at Lincoln Avenue, Port Huron, St. Clair County, MI

  4. White-throated sparrows calibrate their magnetic compass by polarized light cues during both autumn and spring migration.

    PubMed

    Muheim, Rachel; Phillips, John B; Deutschlander, Mark E

    2009-11-01

    The interaction and hierarchy of celestial and magnetic compass cues used by migratory songbirds for orientation has long been the topic of an intense debate. We have previously shown that migratory Savannah sparrows, Passerculus sandwichensis, use polarized light cues near the horizon at sunrise and sunset to recalibrate their magnetic compass. Birds exposed to a +/-90 deg. shifted artificial polarization pattern at sunrise or sunset recalibrated their magnetic compass, but only when given full access to celestial cues, including polarized light cues near the horizon. In the current study, we carried out cue conflict experiments with white-throated sparrows, Zonotrichia albicollis, during both spring and autumn migration in a transition zone between the species' breeding and wintering areas on the south shore of Lake Ontario. We show that white-throated sparrows also recalibrate their magnetic compass by polarized light cues at sunrise and sunset. Sunrise exposure to an artificial polarization pattern shifted relative to the natural magnetic field or exposure to a shift of the magnetic field relative to the natural sky both led to recalibration of the magnetic compass, demonstrating that artificial polarizing filters do not create an anomalous, unnatural orientation response. Our results further indicate that there is no evidence for a difference in compass hierarchy between different phases of migration, confirming previous work showing that polarized light cues near the horizon at sunrise and sunset provide the primary calibration reference both in the beginning and at the end of migration. PMID:19837888

  5. Compassion.

    PubMed

    Saunders, John

    2015-04-01

    The term 'compassion' has been much used and little discussed. I argue that compassion is a virtue in the Aristotelian sense, one of a family of other-regarding properties and belongs to the affective qualities of a moral agent. Its exercise is an essential component of good medical care in many situations and requires grounding in moral principles. Although our dispositions vary, compassion is a quality that can be developed in all of us. PMID:25824061

  6. 46 CFR 32.15-35 - Magnetic Compass and Gyrocompass-T/OC.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Magnetic Compass and Gyrocompass-T/OC. 32.15-35...Equipment § 32.15-35 Magnetic Compass and Gyrocompass—T/OC. (a...service must be fitted with a magnetic compass. (b) All tankships of...

  7. 46 CFR 32.15-35 - Magnetic Compass and Gyrocompass-T/OC.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Magnetic Compass and Gyrocompass-T/OC. 32.15-35...Equipment § 32.15-35 Magnetic Compass and Gyrocompass—T/OC. (a...service must be fitted with a magnetic compass. (b) All tankships of...

  8. 46 CFR 32.15-35 - Magnetic Compass and Gyrocompass-T/OC.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Magnetic Compass and Gyrocompass-T/OC. 32.15-35...Equipment § 32.15-35 Magnetic Compass and Gyrocompass—T/OC. (a...service must be fitted with a magnetic compass. (b) All tankships of...

  9. 46 CFR 32.15-35 - Magnetic Compass and Gyrocompass-T/OC.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Magnetic Compass and Gyrocompass-T/OC. ...Navigation Equipment § 32.15-35 Magnetic Compass and Gyrocompass—T/OC. ...coastwise service must be fitted with a magnetic compass. (b) All tankships...

  10. 46 CFR 32.15-35 - Magnetic Compass and Gyrocompass-T/OC.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Magnetic Compass and Gyrocompass-T/OC. ...Navigation Equipment § 32.15-35 Magnetic Compass and Gyrocompass—T/OC. ...coastwise service must be fitted with a magnetic compass. (b) All tankships...

  11. Applications of magnetic sensors for low cost compass systems

    Microsoft Academic Search

    Michael J. Caruso

    2000-01-01

    A method for heading determination is described that will include the effects of pitch and roll as well as the magnetic properties of the vehicle. Using solid-state magnetic sensors and a tilt sensor, a low cost compass system can be realized. Commercial airlines today use attitude and heading reference systems that cost tens of thousands of dollars. For general aviation,

  12. Antennal circadian clocks coordinate sun compass orientation in migratory monarch butterflies.

    PubMed

    Merlin, Christine; Gegear, Robert J; Reppert, Steven M

    2009-09-25

    During their fall migration, Eastern North American monarch butterflies (Danaus plexippus) use a time-compensated Sun compass to aid navigation to their overwintering grounds in central Mexico. It has been assumed that the circadian clock that provides time compensation resides in the brain, although this assumption has never been examined directly. Here, we show that the antennae are necessary for proper time-compensated Sun compass orientation in migratory monarch butterflies, that antennal clocks exist in monarchs, and that they likely provide the primary timing mechanism for Sun compass orientation. These unexpected findings pose a novel function for the antennae and open a new line of investigation into clock-compass connections that may extend widely to other insects that use this orientation mechanism. PMID:19779201

  13. Antennal circadian clocks coordinate sun compass orientation in migratory monarch butterflies#

    PubMed Central

    Merlin, Christine; Gegear, Robert J.

    2009-01-01

    During their fall migration, Eastern North American monarch butterflies (Danaus plexippus) use a time-compensated sun compass to aid navigation to their overwintering grounds in central Mexico. It has been assumed that the circadian clock that provides time compensation resides in the brain, although this assumption has never been examined directly. Here we show that the antennae are necessary for proper time-compensated sun compass orientation in migratory monarch butterflies, that antennal clocks exist in monarchs, and that they likely provide the primary timing mechanism for sun compass orientation. These unexpected findings pose a novel function for the antennae and open a new line of investigation into clock-compass connections that may extend widely to other insects that use this orientation mechanism. PMID:19779201

  14. Sun Compass Orientation by Juvenile Green Sea Turtles (Chelonia mydas) CODY R. MOTT

    E-print Network

    Milton, Sarah

    Sun Compass Orientation by Juvenile Green Sea Turtles (Chelonia mydas) CODY R. MOTT 1 AND MICHAEL while they swam tethered inside a large circular outdoor pool and were exposed to the sun. The turtles, the predicted direction if they used the sun for orientation. Westward orientation was unaffected by placing

  15. Retinal cryptochrome in a migratory passerine bird: a possible transducer for the avian magnetic compass.

    PubMed

    Möller, Andrea; Sagasser, Sven; Wiltschko, Wolfgang; Schierwater, Bernd

    2004-12-01

    The currently discussed model of magnetoreception in birds proposes that the direction of the magnetic field is perceived by radical-pair processes in specialized photoreceptors, with cryptochromes suggested as potential candidate molecules mediating magnetic compass information. Behavioral studies have shown that magnetic compass orientation takes place in the eye and requires light from the blue-green part of the spectrum. Cryptochromes are known to absorb in the same spectral range. Because of this we searched for cryptochrome (CRY) in the retina of European robins, Erithacus rubecula, passerine birds that migrate at night. Here, we report three individually expressed cryptochromes, eCRY1a, eCRY1b, and eCRY2. While eCRY1a and eCRY2 are similar to the cryptochromes found in the retina of the domestic chicken, eCRY1b has a unique carboxy (C)-terminal. In light of the 'radical-pair' model, our findings support a potential role of cryptochromes as transducers for the perception of magnetic compass information in birds. PMID:15551029

  16. Calibration of the magnetic compass of a migratory bird by celestial rotation

    Microsoft Academic Search

    Kenneth P. Able; Mary A. Able

    1990-01-01

    MIGRATORY birds use a variety of environmental stimuli in orientation. Species that migrate primarily at night can use compasses based on the geomagnetic field, stars, the Sun and patterns of skylight polarization1-4. These compass mechanisms can interact both when migratory birds make day-to-day orientation decisions5 and during their ontogeny in young birds6,7. All of the known compasses used by migratory

  17. Interacting Compasses

    ERIC Educational Resources Information Center

    Riveros, Hector G.; Betancourt, Julian

    2009-01-01

    The use of multiple compasses to map and visualize magnetic fields is well-known. The magnetic field exerts a torque on the compasses aligning them along the lines of force. Some science museums show the field of a magnet using a table with many compasses in a closely packed arrangement. However, the very interesting interactions that occur…

  18. Daytime calibration of magnetic orientation in a migratory bird requires a view of skylight polarization

    Microsoft Academic Search

    Kenneth P. Able; Mary A. Able

    1993-01-01

    THE orientation of migratory birds is based on a complex of interacting compass mechanisms (the geomagnetic field, stars, patterns of skylight polarization and, perhaps, the Sun)1,2. A magnetic compass develops in birds that have never seen the sky3-8, but the preferred direction of magnetic orientation may be modified during the first three months of life by exposing naive birds to

  19. Particle filter-based Heading Estimation using Magnetic Compasses for Mobile Robot Navigation

    Microsoft Academic Search

    Woong Kwon; Kyoung-sig Roh; Hak-kyung Sung

    2006-01-01

    Heading information is critical for the control and\\/or navigation of mobile devices and robots. To get accurate heading information robustly, we propose a method which combines particle filtering with magnetic compasses. Although magnetic compasses can provide absolute heading angle, they have not been used for indoor applications since serious magnetic interferences are commonly founded in home\\/office environments. We overcome this

  20. Probing a chemical compass: novel variants of low-frequency reaction yield detected magnetic resonance.

    PubMed

    Maeda, Kiminori; Storey, Jonathan G; Liddell, Paul A; Gust, Devens; Hore, P J; Wedge, C J; Timmel, Christiane R

    2015-02-01

    We present a study of a carotenoid-porphyrin-fullerene triad previously shown to function as a chemical compass: the photogenerated carotenoid-fullerene radical pair recombines at a rate sensitive to the orientation of an applied magnetic field. To characterize the system we develop a time-resolved Low-Frequency Reaction Yield Detected Magnetic Resonance (tr-LF-RYDMR) technique; the effect of varying the relative orientation of applied static and 36 MHz oscillating magnetic fields is shown to be strongly dependent on the strength of the oscillating magnetic field. RYDMR is a diagnostic test for involvement of the radical pair mechanism in the magnetic field sensitivity of reaction rates or yields, and has previously been applied in animal behavioural experiments to verify the involvement of radical-pair-based intermediates in the magnetic compass sense of migratory birds. The spectroscopic selection rules governing RYDMR are well understood at microwave frequencies for which the so-called 'high-field approximation' is valid, but at lower frequencies different models are required. For example, the breakdown of the rotating frame approximation has recently been investigated, but less attention has so far been given to orientation effects. Here we gain physical insights into the interplay of the different magnetic interactions affecting low-frequency RYDMR experiments performed in the challenging regime in which static and oscillating applied magnetic fields as well as internal electron-nuclear hyperfine interactions are of comparable magnitude. Our observations aid the interpretation of existing RYDMR-based animal behavioural studies and will inform future applications of the technique to verify and characterize further the biological receptors involved in avian magnetoreception. PMID:25537133

  1. Magnetic Sensitivity and Entanglement Dynamics of the Chemical Compass

    E-print Network

    I. K. Kominis

    2012-07-25

    We present the quantum limits to the magnetic sensitivity of a new kind of magnetometer based on biochemical reactions. Radical-ion-pair reactions, the biochemical system underlying the chemical compass, are shown to offer a new and unique physical realization of a magnetic field sensor competitive to modern atomic or condensed matter magnetometers. We elaborate on the quantum coherence and entanglement dynamics of this sensor, showing that they provide the physical basis for testing our understanding of the fundamental quantum dynamics of radical-ion-pair reactions.

  2. Evidence for calibration of magnetic migratory orientation in Savannah sparrows reared in the field

    PubMed Central

    P.Able, K.; A.Able, M.

    1999-01-01

    The orientation system of migratory birds consists of a magnetic compass and compasses based upon celestial cues. In many places, magnetic compass directions and true or geographic compass directions differ (referred to as magnetic declination). It has been demonstrated experimentally in several species that the innate preferred direction of magnetic orientation can be calibrated by celestial rotation, an indicator of geographic directions. This calibration process brings the two types of compass into conformity and provides the birds with a mechanism that compensates for the spatial variation in magnetic declination. Calibration of magnetic orientation has heretofore been demonstrated only with hand-raised birds exposed to very large declination (90° or more). Here we show that the magnetic orientation of wild birds from near Albany, New York, USA (declination = 14° W) was N–S, a clockwise shift of 26° from the NNW–SSE direction of birds raised entirely indoors. Hand-raised birds having visual experience with either the daytime sky or both day and night sky orientated N–S, similar to wild-caught birds. These data provide the first confirmation that calibration of magnetic orientation occurs under natural conditions and in response to modest declination values.

  3. Resonant magnetic perturbations and edge ergodization on the COMPASS tokamak

    SciTech Connect

    Cahyna, P. [Association EURATOM/IPP.CR, Institute of Plasma Physics AS CR v.v.i (Czech Republic); Becoulet, M.; Panek, R. [CEA Cadarache, Association EURATOM-CEA (France); Fuchs, V. [Association EURATOM/IPP.CR, Institute of Plasma Physics AS CR v.v.i (Czech Republic); Nardon, E. [CEA Cadarache, Association EURATOM-CEA (France); Krlin, L. [Association EURATOM/IPP.CR, Institute of Plasma Physics AS CR v.v.i (Czech Republic)

    2008-09-15

    Results of calculations of resonant magnetic perturbation spectra on the COMPASS tokamak are presented. Spectra of the perturbations are calculated from the vacuum field of the perturbation coils. Ergodization is then estimated by applying the criterion of overlap of the resulting islands and verified by field line tracing. Results show that for the chosen configuration of perturbation coils an ergodic layer appears in the pedestal region. The ability to form an ergodic layer is similar to the theoretical results for the ELM suppression experiment at DIII-D; thus, a comparable effect on ELMs can be expected.

  4. Role of exchange and dipolar interactions in the radical pair model of the avian magnetic compass.

    PubMed

    Efimova, Olga; Hore, P J

    2008-03-01

    It is not yet understood how migratory birds sense the Earth's magnetic field as a source of compass information. One suggestion is that the magnetoreceptor involves a photochemical reaction whose product yields are sensitive to external magnetic fields. Specifically, a flavin-tryptophan radical pair is supposedly formed by photoinduced sequential electron transfer along a chain of three tryptophan residues in a cryptochrome flavoprotein immobilized in the retina. The electron Zeeman interaction with the Earth's magnetic field ( approximately 50 microT), modulated by anisotropic magnetic interactions within the radicals, causes the product yields to depend on the orientation of the receptor. According to well-established theory, the radicals would need to be separated by >3.5 nm in order that interradical spin-spin interactions are weak enough to permit a approximately 50 microT field to have a significant effect. Using quantum mechanical simulations, it is shown here that substantial changes in product yields can nevertheless be expected at the much smaller separation of 2.0 +/- 0.2 nm where the effects of exchange and dipolar interactions partially cancel. The terminal flavin-tryptophan radical pair in cryptochrome has a separation of approximately 1.9 nm and is thus ideally placed to act as a magnetoreceptor for the compass mechanism. PMID:17981903

  5. Magnetic compass of migratory Savannah sparrows is calibrated by skylight polarization at sunrise and sunset

    Microsoft Academic Search

    Rachel Muheim; Susanne Åkesson; John B. Phillips

    2007-01-01

    Migratory birds use compass systems derived from the geomagnetic field, the stars, the sun and polarized light patterns. We\\u000a tested whether birds use a single underlying reference system for calibration of these compasses and, specifically, whether\\u000a sunset and sunrise polarized light cues from the region of the sky near the horizon are used to calibrate the magnetic compass.\\u000a We carried

  6. Migrating Songbirds Recalibrate Their Magnetic Compass Daily from Twilight Cues

    Microsoft Academic Search

    William W. Cochran; Henrik Mouritsen; Martin Wikelski

    2004-01-01

    Night migratory songbirds can use stars, sun, geomagnetic field, and polarized light for orientation when tested in captivity. We studied the interaction of magnetic, stellar, and twilight orientation cues in free-flying songbirds. We exposed Catharus thrushes to eastward-turned magnetic fields during the twilight period before takeoff and then followed them for up to 1100 kilometers. Instead of heading north, experimental

  7. Magnetic Compass of Birds Is Based on a Molecule with Optimal Directional Sensitivity

    Microsoft Academic Search

    Thorsten Ritz; Roswitha Wiltschko; P. J. Hore; Christopher T. Rodgers; Katrin Stapput; Peter Thalau; Christiane R. Timmel; Wolfgang Wiltschko

    2009-01-01

    The avian magnetic compass has been well characterized in behavioral tests: it is an “inclination compass” based on the inclination of the field lines rather than on the polarity, and its operation requires short-wavelength light. The “radical pair” model suggests that these properties reflect the use of specialized photopigments in the primary process of magnetoreception; it has recently been supported

  8. Sun compass orientation in seed-caching corvids: its role in spatial memory

    Microsoft Academic Search

    Wolfgang Wiltschko; Russell P. Balda; Mathias Jahnel; Roswitha Wiltschko

    1999-01-01

    The role of sun compass orientation in spatial memory of Clark’s nutcrackers, Nucifraga columbiana, and pinyon jays, Gymnorhinus cyanocephalus, was studied in a series of cache recovery experiments. Birds were tested in an octagonal outdoor aviary with sand-filled\\u000a cups inserted in the floor. For caching, only 12 such cups in a 90° sector were available, while for recovery 4–7 days

  9. The ancestral circadian clock of monarch butterflies: role in time-compensated sun compass orientation.

    PubMed

    Reppert, S M

    2007-01-01

    The circadian clock has a vital role in monarch butterfly (Danaus plexippus) migration by providing the timing component of time-compensated sun compass orientation, which contributes to navigation to the overwintering grounds. The location of circadian clock cells in monarch brain has been identified in the dorsolateral protocerebrum (pars lateralis); these cells express PERIOD, TIMELESS, and a Drosophila-like cryptochrome designated CRY1. Monarch butterflies, like all other nondrosophilid insects examined so far, express a second cry gene (designated insect CRY2) that encodes a vertebrate-like CRY that is also expressed in pars lateralis. An ancestral circadian clock mechanism has been defined in monarchs, in which CRY1 functions as a blue light photoreceptor for photic entrainment, whereas CRY2 functionswithin the clockwork as themajor transcriptional repressor of an intracellular negative transcriptional feedback loop. A CRY1-staining neural pathway has been identified that may connect the circadian (navigational) clock to polarized light input important for sun compass navigation, and a CRY2-positive neural pathway has been discovered that may communicate circadian information directly from the circadian clock to the central complex, the likely site of the sun compass. The monarch butterfly may thus use the CRY proteins as components of the circadian mechanism and also as output molecules that connect the clock to various aspects of the sun compass apparatus. PMID:18419268

  10. Rapid Learning of Magnetic Compass Direction by C57BL/6 Mice in a 4-Armed ‘Plus’ Water Maze

    PubMed Central

    Phillips, John B.; Youmans, Paul W.; Muheim, Rachel; Sloan, Kelly A.; Landler, Lukas; Painter, Michael S.; Anderson, Christopher R.

    2013-01-01

    Magnetoreception has been demonstrated in all five vertebrate classes. In rodents, nest building experiments have shown the use of magnetic cues by two families of molerats, Siberian hamsters and C57BL/6 mice. However, assays widely used to study rodent spatial cognition (e.g. water maze, radial arm maze) have failed to provide evidence for the use of magnetic cues. Here we show that C57BL/6 mice can learn the magnetic direction of a submerged platform in a 4-armed (plus) water maze. Naïve mice were given two brief training trials. In each trial, a mouse was confined to one arm of the maze with the submerged platform at the outer end in a predetermined alignment relative to magnetic north. Between trials, the training arm and magnetic field were rotated by 180° so that the mouse had to swim in the same magnetic direction to reach the submerged platform. The directional preference of each mouse was tested once in one of four magnetic field alignments by releasing it at the center of the maze with access to all four arms. Equal numbers of responses were obtained from mice tested in the four symmetrical magnetic field alignments. Findings show that two training trials are sufficient for mice to learn the magnetic direction of the submerged platform in a plus water maze. The success of these experiments may be explained by: (1) absence of alternative directional cues (2), rotation of magnetic field alignment, and (3) electromagnetic shielding to minimize radio frequency interference that has been shown to interfere with magnetic compass orientation of birds. These findings confirm that mice have a well-developed magnetic compass, and give further impetus to the question of whether epigeic rodents (e.g., mice and rats) have a photoreceptor-based magnetic compass similar to that found in amphibians and migratory birds. PMID:24023673

  11. X-ray compass for determining device orientation

    DOEpatents

    Da Silva, Luiz B. (Danville, CA); Matthews, Dennis L. (Moss Beach, CA); Fitch, Joseph P. (Livermore, CA); Everett, Matthew J. (Pleasanton, CA); Colston, Billy W. (Livermore, CA); Stone, Gary F. (Livermore, CA)

    1999-01-01

    An apparatus and method for determining the orientation of a device with respect to an x-ray source. In one embodiment, the present invention is coupled to a medical device in order to determine the rotational orientation of the medical device with respect to the x-ray source. In such an embodiment, the present invention is comprised of a scintillator portion which is adapted to emit photons upon the absorption of x-rays emitted from the x-ray source. An x-ray blocking portion is coupled to the scintillator portion. The x-ray blocking portion is disposed so as to vary the quantity of x-rays which penetrate the scintillator portion based upon the particular rotational orientation of the medical device with respect to the x-ray source. A photon transport mechanism is also coupled to the scintillator portion. The photon transport mechanism is adapted to pass the photons emitted from the scintillator portion to an electronics portion. By analyzing the quantity of the photons, the electronics portion determines the rotational orientation of the medical device with respect to the x-ray source.

  12. The bookmark and the compass: orientation tools for hypertext users

    Microsoft Academic Search

    Mark Bernstein

    1988-01-01

    The power of hypertext stems chiefly from the complex networks of conceptual links which hypertext documents can render explicit. This paper describes an array of orientation tools which help readers to choose a course through a complex information network without undue confusion or discomfort, while retaining the excitement and spontaneity users often experience when exploring complex information environments.

  13. X-ray compass for determining device orientation

    DOEpatents

    Da Silva, L.B.; Matthews, D.L.; Fitch, J.P.; Everett, M.J.; Colston, B.W.; Stone, G.F.

    1999-06-15

    An apparatus and method for determining the orientation of a device with respect to an x-ray source are disclosed. In one embodiment, the present invention is coupled to a medical device in order to determine the rotational orientation of the medical device with respect to the x-ray source. In such an embodiment, the present invention is comprised of a scintillator portion which is adapted to emit photons upon the absorption of x-rays emitted from the x-ray source. An x-ray blocking portion is coupled to the scintillator portion. The x-ray blocking portion is disposed so as to vary the quantity of x-rays which penetrate the scintillator portion based upon the particular rotational orientation of the medical device with respect to the x-ray source. A photon transport mechanism is also coupled to the scintillator portion. The photon transport mechanism is adapted to pass the photons emitted from the scintillator portion to an electronics portion. By analyzing the quantity of the photons, the electronics portion determines the rotational orientation of the medical device with respect to the x-ray source. 25 figs.

  14. Sun Compass Orientation Helps Coral Reef Fish Larvae Return to Their Natal Reef

    PubMed Central

    Mouritsen, Henrik; Atema, Jelle; Kingsford, Michael J.; Gerlach, Gabriele

    2013-01-01

    Reef fish sustain populations on isolated reefs and show genetic diversity between nearby reefs even though larvae of many species are swept away from the natal site during pelagic dispersal. Retention or recruitment to natal reefs requires orientation capabilities that enable larvae to find their way. Although olfactory and acoustically based orientation has been implicated in homing when larvae are in the reef’s vicinity, it is still unclear how they cope with greater distances. Here we show evidence for a sun compass mechanism that can bring the larvae to the vicinity of their natal reef. In a circular arena, pre-settlement larvae and early settlers (<24 hours) of the cardinal fish, Ostorhinchus doederleini, showed a strong SSE directional swimming response, which most likely has evolved to compensate for the locally prevailing large scale NNW current drift. When fish were clock-shifted 6 hours, they changed their orientation by ca. 180° as predicted by the tropical sun curve at One Tree Island, i.e. they used a time-compensated sun compass. Furthermore, the fish oriented most consistently at times of the day when the sun azimuth is easy to determine. Microsatellite markers showed that the larvae that had just arrived at One Tree Island genetically belonged to either the local reef population or to Fitzroy Reef located 12 kilometers to the SSE. The use of a sun compass adds a missing long-distance link to the hierarchy of other sensory abilities that can direct larvae to the region of origin, including their natal reef. Predominant local recruitment, in turn, can contribute to genetic isolation and potential speciation. PMID:23840396

  15. Discordant timing between antennae disrupts sun compass orientation in migratory monarch butterflies.

    PubMed

    Guerra, Patrick A; Merlin, Christine; Gegear, Robert J; Reppert, Steven M

    2012-01-01

    To navigate during their long-distance migration, monarch butterflies (Danaus plexippus) use a time-compensated sun compass. The sun compass timing elements reside in light-entrained circadian clocks in the antennae. Here we show that either antenna is sufficient for proper time compensation. However, migrants with either antenna painted black (to block light entrainment) and the other painted clear (to permit light entrainment) display disoriented group flight. Remarkably, when the black-painted antenna is removed, re-flown migrants with a single, clear-painted antenna exhibit proper orientation behaviour. Molecular correlates of clock function reveal that period and timeless expression is highly rhythmic in brains and clear-painted antennae, while rhythmic clock gene expression is disrupted in black-painted antennae. Our work shows that clock outputs from each antenna are processed and integrated together in the monarch time-compensated sun compass circuit. This dual timing system is a novel example of the regulation of a brain-driven behaviour by paired organs. PMID:22805565

  16. Discordant timing between antennae disrupts sun compass orientation in migratory monarch butterflies

    PubMed Central

    Guerra, Patrick A; Merlin, Christine; Gegear, Robert J; Reppert, Steven M

    2014-01-01

    To navigate during their long-distance migration, monarch butterflies (Danaus plexippus) use a time-compensated sun compass. The sun compass timing elements reside in light-entrained circadian clocks in the antennae. Here we show that either antenna is sufficient for proper time compensation. However, migrants with either antenna painted black (to block light entrainment) and the other painted clear (to permit light entrainment) display disoriented group flight. Remarkably, when the black-painted antenna is removed, re-flown migrants with a single, clear-painted antenna exhibit proper orientation behaviour. Molecular correlates of clock function reveal that period and timeless expression is highly rhythmic in brains and clear-painted antennae, while rhythmic clock gene expression is disrupted in black-painted antennae. Our work shows that clock outputs from each antenna are processed and integrated together in the monarch time-compensated sun compass circuit. This dual timing system is a novel example of the regulation of a brain-driven behaviour by paired organs. PMID:22805565

  17. 46 CFR 28.230 - Compasses.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Compasses. 28.230 Section 28.230 ...the Aleutian Trade § 28.230 Compasses. Each vessel must be equipped with an operable magnetic steering compass with a compass deviation table...

  18. 46 CFR 28.230 - Compasses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Compasses. 28.230 Section 28.230 ...the Aleutian Trade § 28.230 Compasses. Each vessel must be equipped with an operable magnetic steering compass with a compass deviation table...

  19. 46 CFR 28.230 - Compasses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Compasses. 28.230 Section 28.230 ...the Aleutian Trade § 28.230 Compasses. Each vessel must be equipped with an operable magnetic steering compass with a compass deviation table...

  20. 46 CFR 28.230 - Compasses.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Compasses. 28.230 Section 28.230 ...the Aleutian Trade § 28.230 Compasses. Each vessel must be equipped with an operable magnetic steering compass with a compass deviation table...

  1. 46 CFR 28.230 - Compasses.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Compasses. 28.230 Section 28.230 ...the Aleutian Trade § 28.230 Compasses. Each vessel must be equipped with an operable magnetic steering compass with a compass deviation table...

  2. The depth of the honeybee's backup sun-compass systems.

    PubMed

    Dovey, Katelyn M; Kemfort, Jordan R; Towne, William F

    2013-06-01

    Honeybees have at least three compass mechanisms: a magnetic compass; a celestial or sun compass, based on the daily rotation of the sun and sun-linked skylight patterns; and a backup celestial compass based on a memory of the sun's movements over time in relation to the landscape. The interactions of these compass systems have yet to be fully elucidated, but the celestial compass is primary in most contexts, the magnetic compass is a backup in certain contexts, and the bees' memory of the sun's course in relation to the landscape is a backup system for cloudy days. Here we ask whether bees have any further compass systems, for example a memory of the sun's movements over time in relation to the magnetic field. To test this, we challenged bees to locate the sun when their known celestial compass systems were unavailable, that is, under overcast skies in unfamiliar landscapes. We measured the bees' knowledge of the sun's location by observing their waggle dances, by which foragers indicate the directions toward food sources in relation to the sun's compass bearing. We found that bees have no celestial compass systems beyond those already known: under overcast skies in unfamiliar landscapes, bees attempt to use their landscape-based backup system to locate the sun, matching the landscapes or skylines at the test sites with those at their natal sites as best they can, even if the matches are poor and yield weak or inconsistent orientation. PMID:23430992

  3. Celestial orientation with the sun not in view: lizards use a time-compensated sky polarization compass.

    PubMed

    Maoret, Francesco; Beltrami, Giulia; Bertolucci, Cristiano; Foà, Augusto

    2014-04-01

    The present investigation was aimed at testing whether the lizard sky polarization compass is time compensated. For this purpose, ruin lizards, Podarcis sicula, were both trained and tested for orientation inside a Morris water maze under clear skies with the sun not in view. During training, lizards showed a striking bimodal orientation along the training axis, demonstrating their capability of determining the symmetry plane of the sky polarization pattern and thus the use of polarization information in orientation. After reaching criteria, lizards were kept 7 days in a 6-h fast clock-shift treatment and then released with the sun not in view. Six-hour clock-shifted lizards showed a bimodal distribution of directional choices, which was oriented perpendicularly to the training axis, as it was expected on the basis of the clock-shift. The results show that the only celestial diurnal compass mechanism that does not need a direct vision of the sun disk (i.e., the sky polarization compass) is a time-compensated compass. PMID:24682208

  4. Migratory blackcaps tested in Emlen funnels can orient at 85 degrees but not at 88 degrees magnetic inclination.

    PubMed

    Lefeldt, Nele; Dreyer, David; Schneider, Nils-Lasse; Steenken, Friederike; Mouritsen, Henrik

    2015-01-15

    Migratory birds are known to use the Earth's magnetic field as an orientation cue on their tremendous journeys between their breeding and overwintering grounds. The magnetic compass of migratory birds relies on the magnetic field's inclination, i.e. the angle between the magnetic field lines and the Earth's surface. As a consequence, vertical or horizontal field lines corresponding to 0 or 90 deg inclination should offer no utilizable information on where to find North or South. So far, very little is known about how small the deviations from horizontal or vertical inclination are that migratory birds can detect and use as a reference for their magnetic compass. Here, we asked: what is the steepest inclination angle at which a migratory bird, the Eurasian blackcap (Sylvia atricapilla), can still perform magnetic compass orientation in Emlen funnels? Our results show that blackcaps are able to orient in an Earth's strength magnetic field with inclination angles of 67 and 85 deg, but fail to orient in a field with 88 deg inclination. This suggests that the steepest inclination angle enabling magnetic compass orientation in migratory blackcaps tested in Emlen funnels lies between 85 and 88 deg. PMID:25452505

  5. Research Papers Light-Dependent Shift in Bullfrog Tadpole Magnetic Compass

    E-print Network

    Phillips, John B.

    the presence of a light-dependent magnetic compass in a urodele amphibian, the eastern red-spotted newt Notophthalmus viridescens, mediated by extraocular photoreceptors located in or near the pineal organ. Newts relative to newts tested under full spectrum (white) or short-wavelength light. Here we report

  6. The optimization of resonant magnetic perturbation spectra for the COMPASS tokamak

    NASA Astrophysics Data System (ADS)

    Cahyna, P.; Pánek, R.; Fuchs, V.; Krlín, L.; Bécoulet, M.; Huysmans, G.; Nardon, E.

    2009-05-01

    The COMPASS tokamak, recently transferred from UKAEA Culham to IPP Prague, is equipped with a set of saddle coils for producing controlled resonant magnetic perturbations (RMPs). In the future experimental programme of COMPASS we plan to focus on studies of RMPs, especially in view of their application as an ELM control mechanism and their considered use in ITER. In the present contribution we describe the preparatory calculations for the planned experiments. We computed the spectra of perturbations for several different equilibria predicted by MHD simulations and determined the positions and sizes of the resulting islands. It is shown how the saddle coils of COMPASS can be adapted to our equilibria to obtain good island overlap at the edge, which is believed to be a key component in the ELM mitigation effect. The techniques used for adapting the coils to achieve this result are described. Those are fairly general and could be used in the design of RMP coils on other machines.

  7. Vehicle Detection and Compass Applications using AMR Magnetic Sensors

    Microsoft Academic Search

    Michael J. Caruso; Lucky S. Withanawasam

    The earliest magnetic field detectors allowed navigation over trackless oceans by sensing the earth's magnetic poles. Magnetic field sensing has vastly expanded as industry has adapted a variety of magnetic sensors to detect the presence, strength, or direction of magnetic fields not only from the earth, but also from permanent magnets, magnetized soft magnets, vehicle distur- bances, brain wave activity,

  8. Interactions in the flexible orientation system of a migratory bird

    Microsoft Academic Search

    Kenneth P. Able; Mary A. Able

    1995-01-01

    MIGRATING birds rely on interacting compass senses: magnetic, star, polarized light and perhaps Sun compasses1,2. During the development of orientation mechanisms, celestial rotation of stars at night3 and of polarized skylight patterns during the day time4 provide information about true compass directions that calibrates the direction of migration selected using the magnetic compass3-11. It might often be advantageous to adjust

  9. Visual compass Frederic Labrosse

    E-print Network

    Labrosse, Frédéric

    Visual compass Fr´ed´eric Labrosse Department of Computer Science University of Wales, Aberystwyth://www.taros.org.uk. #12;Visual compass Fr´ed´eric Labrosse Department of Computer Science University of Wales Aberystwyth results that show a performance similar to a magnetic compass. In particular, the heading measured

  10. Create a Compass

    NSDL National Science Digital Library

    In this OLogy activity, kids learn how a compass works and why it will always point north. The activity begins with an overview that discusses our reliance on directions and how a compass works. Students are then given step-by-step, illustrated directions for creating a compass with a sewing needle, a small bar magnet, a small piece of foam, and other household items. The activity includes ideas about how to try out your compass.

  11. Color appearance in interior daylight: observations of hue shifts in different compass orientations

    NASA Astrophysics Data System (ADS)

    Harleman, Maud

    2002-06-01

    In this paper problems, aims, and preliminary results from an investigation of color appearance in north- and south- facing rooms are presented. This first part of the project includes an experimental study of six colors in two nuances of chromaticness, altogether twelve colors. Several methods for assessment and description have been used. Hue shifts are in focus together with chromaticness and room character. Color appearance was compared between rooms in different compass orientations and found to be clearly different. In the south facing room yellow colors tended towards elementary yellow, while greenish blue tended towards green. All colors increased in chromaticness. Colors in the north- facing room, on the other hand, tended to go in the opposite direction; greenish blue tended towards elementary blue and elementary blue increased its cromaticness most of all. Reddish blue colors showed no distinct tendency. Color variations due to reflexes, patches of light, shade and, shadow were important in assessing the identity color. The identity color is discussed together with the elasticity concept that has been developed to describe the range of different color appearances of an inherent color inside the room.

  12. Avian orientation at steep angles of inclination: experiments with migratory white-crowned sparrows at the magnetic North Pole.

    PubMed

    Akesson, S; Morin, J; Muheim, R; Ottosson, U

    2001-09-22

    The Earth's magnetic field and celestial cues provide animals with compass information during migration. Inherited magnetic compass courses are selected based on the angle of inclination, making it difficult to orient in the near vertical fields found at high geomagnetic latitudes. Orientation cage experiments were performed at different sites in high Arctic Canada with adult and young white-crowned sparrows (Zonotrichia leucophrys gambelii) in order to investigate birds' ability to use the Earth's magnetic field and celestial cues for orientation in naturally very steep magnetic fields at and close to the magnetic North Pole. Experiments were performed during the natural period of migration at night in the local geomagnetic field under natural clear skies and under simulated total overcast conditions. The experimental birds failed to select a meaningful magnetic compass course under overcast conditions at the magnetic North Pole, but could do so in geomagnetic fields deviating less than 3 degrees from the vertical. Migratory orientation was successful at all sites when celestial cues were available. PMID:11564346

  13. Magnetic Compass Orientation in Larval Iberian Green Frogs, Pelophylax Perezi

    E-print Network

    Phillips, John B.

    been demonstrated in the cave salamander, Eurycea lucifuga (Phillips 1977), Eastern red-spotted newts et al. 2000) and, more recently, in alpine newts, Mesotriton alpestris (Diego- Rasilla 2003; Diego-Rasilla et al. 2005) and Bosca's newts, Lissotriton helveticus (Rodri´guez-Garci´a & Diego-Rasilla 2006

  14. Lateralization of magnetic compass orientation in a migratory bird

    Microsoft Academic Search

    Wolfgang Wiltschko; Joachim Traudt; Onur Güntürkün; Helmut Prior; Roswitha Wiltschko

    2002-01-01

    Lateralization of brain functions, once believed to be a human characteristic, has now been found to be widespread among vertebrates. In birds, asymmetries of visual functions are well studied, with each hemisphere being specialized for different tasks. Here we report lateralized functions of the birds' visual system associated with magnetoperception, resulting in an extreme asymmetry of sensing the direction of

  15. Exact treatment of magnetism-driven ferroelectricity in the one-dimensional compass model

    NASA Astrophysics Data System (ADS)

    You, Wen-Long; Liu, Guang-Hua; Horsch, Peter; Ole?, Andrzej M.

    2014-09-01

    We consider a class of one-dimensional compass models with antisymmetric Dzyaloshinskii-Moriya exchange interaction in an external magnetic field. Based on the exact solution derived by means of Jordan-Wigner transformation, we study the excitation gap, spin correlations, ground-state degeneracy, and critical properties at phase transitions. The phase diagram at finite electric and magnetic field consists of three phases: ferromagnetic, canted antiferromagnetic, and chiral. Dzyaloshinskii-Moriya interaction induces an electrical polarization in the ground state of the chiral phase, where the nonlocal string order and special features of entanglement spectra arise, while strong chiral correlations emerge at finite temperature in the other phases and are controlled by a gap between the nonchiral ground state and the chiral excitations. We further show that the magnetoelectric effects in all phases disappear above a typical temperature corresponding to the total bandwidth of the effective fermionic model. To this end we explore the entropy, specific heat, magnetization, electric polarization, and the magnetoelectric tensor at finite temperature. We identify rather peculiar specific-heat and polarization behavior of the compass model which follows from highly frustrated interactions.

  16. Exact treatment of magnetism-driven ferroelectricity in the one-dimensional compass model

    E-print Network

    Wen-Long You; Guang-Hua Liu; Peter Horsch; Andrzej M. Ole?

    2014-09-20

    We consider a class of one-dimensional compass models with antisymmetric Dzyaloshinskii-Moriya exchange interaction in an external magnetic field. Based on the exact solution derived by means of Jordan-Wigner transformation, we study the excitation gap, spin correlations, ground-state degeneracy, and critical properties at phase transitions. The phase diagram at finite electric and magnetic field consists of three phases: ferromagnetic, canted antiferromagnetic, and chiral. Dzyaloshinskii-Moriya interaction induces an electrical polarization in the ground state of the chiral phase, where the nonlocal string order and special features of entanglement spectra arise, while strong chiral correlations emerge at finite temperature in the other phases and are controlled by a gap between the nonchiral ground state and the chiral excitations. We further show that the magnetoelectric effects in all phases disappear above a typical temperature corresponding to the total bandwidth of the effective fermionic model. To this end we explore the entropy, specific heat, magnetization, electric polarization, and the magnetoelectric tensor at finite temperature. We identify rather peculiar specific-heat and polarization behavior of the compass model which follows from highly frustrated interactions.

  17. Monarch Butterflies (Danaus plexippus L.) Use a Magnetic Compass for Navigation

    Microsoft Academic Search

    Jason A. Etheredge; Sandra M. Perez; Orley R. Taylor; Rudolf Jander

    1999-01-01

    Fall migratory monarch butterflies, tested for their directional responses to magnetic cues under three conditions, amagnetic, normal, and reversed magnetic fields, showed three distinct patterns. In the absence of a magnetic field, monarchs lacked directionality as a group. In the normal magnetic field, monarchs oriented to the southwest with a group pattern typical for migrants. When the horizontal component of

  18. A subterranean mammal uses the magnetic compass for path integration.

    PubMed

    Kimchi, Tali; Etienne, Ariane S; Terkel, Joseph

    2004-01-27

    Path integration allows animals to navigate without landmarks by continuously processing signals generated through locomotion. Insects such as bees and ants have evolved an accurate path integration system, assessing and coding rotations with the help of a general directional reference, the sun azimuth. In mammals, by contrast, this process can take place through purely idiothetic (mainly proprioceptive and vestibular) signals. However, without any stable external reference for measuring direction, path integration is highly affected by cumulative errors and thus has been considered so far as valid only for short-distance navigation. Here we show through two path integration experiments (homing and shortcut finding) that the blind mole rat assesses direction both through internal signals and by estimating its heading in relation to the earth's magnetic field. Further, it is shown that the greater the circumvolution and length of the traveled path, the more the animal relies on the geomagnetic field. This path integration system strongly reduces the accumulation of errors due to inaccuracies in the estimation of rotations and thus allows the mole rat to navigate efficiently in darkness, without the help of any landmark, over both short and long distances. PMID:14732687

  19. Fiber optic compass development 

    E-print Network

    Park, Kyongtae

    2005-11-01

    A fiber optic system for measuring magnetic heading and pitch of one or more compass heads in a towed acoustic array has been developed as a cooperative effort between engineers at Fiber Dynamics, Inc., and faculty and ...

  20. 28. MODIFIED CHAIN SAW FOR CUTTING ROCK CORES; BRUNTON COMPASS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    28. MODIFIED CHAIN SAW FOR CUTTING ROCK CORES; BRUNTON COMPASS STAND FOR DETERMINING CORE'S FIELD ORIENTATION; INSECTICIDE DISPENSER MODIFIED TO LUBRICATE CORE DRILLING PROCESS. - U.S. Geological Survey, Rock Magnetics Laboratory, 345 Middlefield Road, Menlo Park, San Mateo County, CA

  1. Compact Optoelectronic Compass

    NASA Technical Reports Server (NTRS)

    Christian, Carl

    2004-01-01

    A compact optoelectronic sensor unit measures the apparent motion of the Sun across the sky. The data acquired by this chip are processed in an external processor to estimate the relative orientation of the axis of rotation of the Earth. Hence, the combination of this chip and the external processor finds the direction of true North relative to the chip: in other words, the combination acts as a solar compass. If the compass is further combined with a clock, then the combination can be used to establish a threeaxis inertial coordinate system. If, in addition, an auxiliary sensor measures the local vertical direction, then the resulting system can determine the geographic position. This chip and the software used in the processor are based mostly on the same design and operation as those of the unit described in Micro Sun Sensor for Spacecraft (NPO-30867) elsewhere in this issue of NASA Tech Briefs. Like the unit described in that article, this unit includes a small multiple-pinhole camera comprising a micromachined mask containing a rectangular array of microscopic pinholes mounted a short distance in front of an image detector of the active-pixel sensor (APS) type (see figure). Further as in the other unit, the digitized output of the APS in this chip is processed to compute the centroids of the pinhole Sun images on the APS. Then the direction to the Sun, relative to the compass chip, is computed from the positions of the centroids (just like a sundial). In the operation of this chip, one is interested not only in the instantaneous direction to the Sun but also in the apparent path traced out by the direction to the Sun as a result of rotation of the Earth during an observation interval (during which the Sun sensor must remain stationary with respect to the Earth). The apparent path of the Sun across the sky is projected on a sphere. The axis of rotation of the Earth lies at the center of the projected circle on the sphere surface. Hence, true North (not magnetic North), relative to the chip, can be estimated from paths of the Sun images across the APS. In a test, this solar compass has been found to yield a coarse estimate of the North (within tens of degrees) in an observation time of about ten minutes. As expected, the accuracy was found to increase with observation time: after a few hours, the estimated direction of the rotation axis becomes accurate to within a small fraction of a degree.

  2. Differential Compassing Helps Human–Robot Teams Navigate in Magnetically Disturbed Environments

    Microsoft Academic Search

    Vincenzo Genovese; Angelo Maria Sabatini

    2006-01-01

    In this paper, the authors describe a sensing method, called differential compassing, which can be applied to pursue leader\\/follower behaviors in the field of service robotics. Differential compassing is applied to integrate proximity\\/range sensing in robot systems, the operation of which can involve a hands-free interaction mode, where the robot (the follower) reacts to the movements of a walking user

  3. Locomotor activity rhythm and sun compass orientation in the sandhopper Talitrus saltator are related

    Microsoft Academic Search

    Alberto Ugolini; Silvia Somigli; Vittorio Pasquali; Paolo Renzi

    2007-01-01

    The sandhopper Talitrus saltator has an endogenous activity rhythm with a circadian periodicity. It is well known for its ability to compensate for the apparent\\u000a movement of the sun during its migrations along the sea–land axis of the beach. Both chronometric mechanisms are entrained\\u000a by the natural LD photoperiod. Using actographic recordings and tests of solar orientation of individuals kept

  4. Superconducting magnet for nuclei orientation 

    E-print Network

    Wang, Fa-Chung

    1968-01-01

    Elements V Vanadium T ('z) 5 03 0. 85 0 ' 55 H (gauss) 1310, 53 4, p conducting state to the normal state suddenly and com- pletely when the applied magnetic field H reaches its critical value Hc. Below Hc? they are electrically superconducting...

  5. Compass models: Theory and physical motivations

    NASA Astrophysics Data System (ADS)

    Nussinov, Zohar; van den Brink, Jeroen

    2015-01-01

    Compass models are theories of matter in which the couplings between the internal spin (or other relevant field) components are inherently spatially (typically, direction) dependent. A simple illustrative example is furnished by the 90° compass model on a square lattice in which only couplings of the form ?ix?jx (where {?ia}a denote Pauli operators at site i ) are associated with nearest-neighbor sites i and j separated along the x axis of the lattice while ?iy?jy couplings appear for sites separated by a lattice constant along the y axis. Similar compass-type interactions can appear in diverse physical systems. For instance, compass models describe Mott insulators with orbital degrees of freedom where interactions sensitively depend on the spatial orientation of the orbitals involved as well as the low-energy effective theories of frustrated quantum magnets, and a host of other systems such as vacancy centers, and cold atomic gases. The fundamental interdependence between internal (spin, orbital, or other) and external (i.e., spatial) degrees of freedom which underlies compass models generally leads to very rich behaviors, including the frustration of (semi-)classical ordered states on nonfrustrated lattices, and to enhanced quantum effects, prompting, in certain cases, the appearance of zero-temperature quantum spin liquids. As a consequence of these frustrations, new types of symmetries and their associated degeneracies may appear. These intermediate symmetries lie midway between the extremes of global symmetries and local gauge symmetries and lead to effective dimensional reductions. In this article, compass models are reviewed in a unified manner, paying close attention to exact consequences of these symmetries and to thermal and quantum fluctuations that stabilize orders via order-out-of-disorder effects. This is complemented by a survey of numerical results. In addition to reviewing past works, a number of other models are introduced and new results established. In particular, a general link between flat bands and symmetries is detailed.

  6. M'18 COMPASS Wellness Groups Welcome to Tufts University School of Medicine!

    E-print Network

    Dennett, Daniel

    M'18 COMPASS Wellness Groups Welcome to Tufts University School. COMPASS (Co-leader Orientation in Mindfulness for Patients and Student Support aspects of Mindfulness training. COMPASS sign-up will be limited; sign

  7. Sensitivity and entanglement in the avian chemical compass

    NASA Astrophysics Data System (ADS)

    Zhang, Yiteng; Berman, Gennady P.; Kais, Sabre

    2014-10-01

    The radical pair mechanism can help to explain avian orientation and navigation. Some evidence indicates that the intensity of external magnetic fields plays an important role in avian navigation. In this paper, using a two-stage model, we demonstrate that birds could reasonably detect the directions of geomagnetic fields and gradients of these fields using a yield-based chemical compass that is sensitive enough for navigation. Also, we find that the lifetime of entanglement in this proposed compass is angle dependent and long enough to allow adequate electron transfer between molecules.

  8. 46 CFR 121.402 - Compasses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Compasses. 121.402 Section 121.402 Shipping... Navigation Equipment § 121.402 Compasses. (a) Except as otherwise provided...must be fitted with a suitable magnetic compass designed for marine use, to be...

  9. 46 CFR 184.402 - Compasses.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Compasses. 184.402 Section 184.402 Shipping... Navigation Equipment § 184.402 Compasses. (a) Except as otherwise provided...must be fitted with a suitable magnetic compass designed for marine use, to be...

  10. 46 CFR 169.709 - Compass.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Compass. 169.709 Section 169.709 Shipping...Systems, and Equipment § 169.709 Compass. (a) Each vessel must be fitted with a magnetic steering compass. (b) Each vessel certificated...

  11. 46 CFR 121.402 - Compasses.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Compasses. 121.402 Section 121.402 Shipping... Navigation Equipment § 121.402 Compasses. (a) Except as otherwise provided...must be fitted with a suitable magnetic compass designed for marine use, to be...

  12. 46 CFR 121.402 - Compasses.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Compasses. 121.402 Section 121.402 Shipping... Navigation Equipment § 121.402 Compasses. (a) Except as otherwise provided...must be fitted with a suitable magnetic compass designed for marine use, to be...

  13. 46 CFR 121.402 - Compasses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Compasses. 121.402 Section 121.402 Shipping... Navigation Equipment § 121.402 Compasses. (a) Except as otherwise provided...must be fitted with a suitable magnetic compass designed for marine use, to be...

  14. 46 CFR 169.709 - Compass.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Compass. 169.709 Section 169.709 Shipping...Systems, and Equipment § 169.709 Compass. (a) Each vessel must be fitted with a magnetic steering compass. (b) Each vessel certificated...

  15. 46 CFR 184.402 - Compasses.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Compasses. 184.402 Section 184.402 Shipping... Navigation Equipment § 184.402 Compasses. (a) Except as otherwise provided...must be fitted with a suitable magnetic compass designed for marine use, to be...

  16. 46 CFR 184.402 - Compasses.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Compasses. 184.402 Section 184.402 Shipping... Navigation Equipment § 184.402 Compasses. (a) Except as otherwise provided...must be fitted with a suitable magnetic compass designed for marine use, to be...

  17. 46 CFR 169.709 - Compass.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Compass. 169.709 Section 169.709 Shipping...Systems, and Equipment § 169.709 Compass. (a) Each vessel must be fitted with a magnetic steering compass. (b) Each vessel certificated...

  18. 46 CFR 121.402 - Compasses.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Compasses. 121.402 Section 121.402 Shipping... Navigation Equipment § 121.402 Compasses. (a) Except as otherwise provided...must be fitted with a suitable magnetic compass designed for marine use, to be...

  19. 46 CFR 184.402 - Compasses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Compasses. 184.402 Section 184.402 Shipping... Navigation Equipment § 184.402 Compasses. (a) Except as otherwise provided...must be fitted with a suitable magnetic compass designed for marine use, to be...

  20. 46 CFR 184.402 - Compasses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Compasses. 184.402 Section 184.402 Shipping... Navigation Equipment § 184.402 Compasses. (a) Except as otherwise provided...must be fitted with a suitable magnetic compass designed for marine use, to be...

  1. 46 CFR 169.709 - Compass.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Compass. 169.709 Section 169.709 Shipping...Systems, and Equipment § 169.709 Compass. (a) Each vessel must be fitted with a magnetic steering compass. (b) Each vessel certificated...

  2. 46 CFR 169.709 - Compass.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Compass. 169.709 Section 169.709 Shipping...Systems, and Equipment § 169.709 Compass. (a) Each vessel must be fitted with a magnetic steering compass. (b) Each vessel certificated...

  3. Trough Compass with Case, 1916

    USGS Multimedia Gallery

    The storage case has a sliding lid. The compass is marked Troughton & Simms Ltd, London, 1916, No.9214. A trough compass is used with either a plane table or a theodolite. The needle is a long magnetized bar of steel which is pointed at both ends. Object ID: USGS-000824...

  4. The flexible migratory orientation system of the savannah sparrow (Passerculus sandwichensis)

    PubMed

    Able; Able

    1996-01-01

    The orientation system of the Savannah sparrow (Passerculus sandwichensis) is typical of nocturnal migrant passerine birds. It is based on a system of interacting compass senses: magnetic, star, polarized light and, perhaps, sun compasses. The magnetic compass capability develops in birds that have never seen the sky, but the preferred direction of magnetic orientation may be calibrated by celestial rotation (stars at night and polarized skylight patterns during the day). This ability to recalibrate magnetic orientation persists throughout life and enables the bird to compensate for variability in magnetic declination that may be encountered as it migrates. The polarized light compass may be manipulated by exposing young birds to altered patterns of skylight polarization. There is some evidence that the magnetic field may be involved in calibration of the polarized light compass. In short-term orientation decision-making during migration, visual information at sunset overrides both stars and magnetic cues, and polarized skylight is the relevant stimulus in dusk orientation. The star pattern compass seems to be of little importance. This extremely flexible orientation system enables the birds to respond to spatial and temporal variability in the quality and availability of orientation information. PMID:9317228

  5. A Compass and Clinometer Modified for Structural Analysis

    ERIC Educational Resources Information Center

    Amenta, Roddy V.

    1977-01-01

    Describes the modification of the SUUNTO compass and clinometer precision sighting instruments to make a compact geologic compass useful for measuring orientations of S-surfaces and rake angles of lineations. (SL)

  6. A PURPOSE ORIENTED MAGNETIC SEPARATOR: SKIMMER

    SciTech Connect

    Salih Ersayin

    2005-08-09

    A magnetic separator was designed to selectively separate fine-liberated magnetite. The conceptual design was simulated using CFD techniques. A separator tank was fabricated and a magnetic drum was used to capture magnetic particles. The initial tank design was modified to eliminate application oriented problems. The new separator was able to produce a fine product as a concentrate at relatively high feed rates. A plant simulation showed that such a device could lower circulating loads around ball mills by 16%, thereby creating room for a 5-8% increase in throughput at the same energy level. However, it was concluded that further improvements in terms of both size and mineral selectivity are needed to have a marketable product.

  7. Transverse spin effects in COMPASS

    E-print Network

    A. Bressan; for the COMPASS experiment

    2009-02-02

    In the years 2002-2004 COMPASS has collected data with the LiD target polarization oriented transversely with respect to the muon beam direction for about 20% of the running time, to measure transverse spin effects in semi-inclusive deep inelastic scattering, one of the main objectives of the COMPASS spin program. In 2007, COMPASS has used for the first time a proton NH_3 target with the data taking time equally shared between longitudinal and transverse polarization of the target. After reviewing the results obtained with the deuteron, the new results for the Collins and Sivers asymmetries of the proton will be presented.

  8. Self-compassion and social anxiety disorder

    Microsoft Academic Search

    Kelly H. Werner; Hooria Jazaieri; Philippe R. Goldin; Michal Ziv; Richard G. Heimberg; James J. Gross

    2011-01-01

    Self-compassion refers to having an accepting and caring orientation towards oneself. Although self-compassion has been studied primarily in healthy populations, one particularly compelling clinical context in which to examine self-compassion is social anxiety disorder (SAD). SAD is characterized by high levels of negative self-criticism as well as an abiding concern about others' evaluation of one's performance. In the present study,

  9. Self-compassion and social anxiety disorder

    Microsoft Academic Search

    Kelly H. Werner; Hooria Jazaieri; Philippe R. Goldin; Michal Ziv; Richard G. Heimberg; James J. Gross

    2012-01-01

    Self-compassion refers to having an accepting and caring orientation towards oneself. Although self-compassion has been studied primarily in healthy populations, one particularly compelling clinical context in which to examine self-compassion is social anxiety disorder (SAD). SAD is characterized by high levels of negative self-criticism as well as an abiding concern about others’ evaluation of one's performance. In the present study,

  10. A note on the response characteristics of the VACM compass

    Microsoft Academic Search

    S. K. Patch; R. C. Beardsley; S. J. Lentz

    1990-01-01

    Several simple laboratory experiments have been conducted to study the dynamic behavior of the vector averaging current meter (VACM) compass. These experiments demonstrate that the combined eddy current and bearing friction torque on the compass magnet is proportional to the angular velocity difference between the compass magnet and housing. This combined friction torque tends to critically damp the free oscillation

  11. The Cricket Compass for ContextAware Mobile Applications

    E-print Network

    The Cricket Compass for Context­Aware Mobile Applications Nissanka B. Priyantha, Allen K. L. Miu compass, knowledge of orientation through the Cricket com- pass attached to a mobile device enhances, and \\augmented-reality" displays. Our compass infrastructure enhances the spatial inference capability

  12. Environment-induced anisotropy and the sensitivity of the radical pair mechanism in the avian compass

    E-print Network

    Alejandro Carrillo; Marcio F. Cornelio; Marcos C. de Oliveira

    2013-04-10

    Earth's magnetic field is essential for orientation in birds migration. The most promising explanation for this orientation is the photo-stimulated radical pair (RP) mechanism, conjectured to occur in cryptochrome photoreceptors. The radicals must have an intrinsic anisotropy in order to define a reference frame for the compass. This anisotropy, when introduced through hyperfine interactions, imposes immobility of the RP, and implies that entanglement between the unpaired electrons of the RP is preserved over long coherence times. We show that this kind of anisotropy, and consequently the entanglement in the model, are not necessary for the proper functioning of the compass. Classically correlated initial conditions for the RP, subjected to a fast decoherence process, are able to provide the anisotropy required. The environment in which the RP is immersed is then responsible for the reference frame of the compass, relaxing the immobility assumption. This fact significantly expands the range of applicability of the RP mechanism providing more elements for experimental search.

  13. Detection of alterations in human sperm using magnetic orientation techniques

    NASA Astrophysics Data System (ADS)

    Sakhnini, Lama; Dairi, Maheen; Manaa, Hacene

    2007-09-01

    In this study we report on magnetic orientation of human sperms. Samples were taken from 17 donors. Normal human sperms became oriented with their long axis perpendicular to the magnetic field ( 1 Tesla maximum). Total orientation was achieved with magnetic field at about one Tesla, while for abnormal sperms the magnetic behavior was different. The dependence of the measured degree of orientation on the intensity of the magnetic field was in good agreement with the theoretical equation for the magnetic orientation of diamagnetic substances. As a result for a numerical analysis based on the equation, the anisotropic diamagnetic susceptibility of normal sperm was found to be ? ?= 8×10 -20 J/T2. The degree of orientation was influenced by the alterations in the shape of the head, body or the tail. It has been suggested that the DNA in the sperm head retain the strong magnetic anisotropy to counter balance the magnetic anisotropy retained by flagellum microtubules. Recent studies demonstrated a well-defined nuclear architecture in human sperm nucleus, where the head morphology has significant correlation with sperm chromatin structure assay SCSA. Then as the methods to evaluate SCSA can be difficult and expensive our simple magnetic orientation technique can be an alternative to diagnose alteration in DNA.

  14. Compassion: An Evolutionary Analysis and Empirical Review

    PubMed Central

    Goetz, Jennifer L.; Keltner, Dacher; Simon-Thomas, Emiliana

    2010-01-01

    What is compassion? And how did it evolve? In this review, we integrate three evolutionary arguments that converge on the hypothesis that compassion evolved as a distinct affective experience whose primary function is to facilitate cooperation and protection of the weak and those who suffer. Our empirical review reveals compassion to have distinct appraisal processes attuned to undeserved suffering, distinct signaling behavior related to caregiving patterns of touch, posture, and vocalization, and a phenomenological experience and physiological response that orients the individual to social approach. This response profile of compassion differs from those of distress, sadness, and love, suggesting that compassion is indeed a distinct emotion. We conclude by considering how compassion shapes moral judgment and action, how it varies across different cultures, and how it may engage specific patterns of neural activation, as well as emerging directions of research. PMID:20438142

  15. The sun compass revisited.

    PubMed

    Guilford, Tim; Taylor, Graham K

    2014-11-01

    Many animals, and birds in particular, are thought to use directional information from the sun in the form of a time-compensated sun compass, with predictably deviated orientation under clock shift being regarded as the litmus test of this. We suggest that this paradigm obscures a number of other ways in which solar-derived information could be important in animal orientation. We distinguish between the known use of the sun's azimuth to provide absolute geographical direction (compass mechanism) and its possible use to detect changes in heading (heading indicator mechanism). Just as in an aircraft, these two kinds of information may be provided by separate mechanisms and used for different functions, for example for navigation versus steering. We also argue that although a solar compass must be time-referenced to account for the sun's apparent diurnal movement, this need not entail full time compensation. This is because animals might also use time-dependent solar information in an associatively acquired, and hence time-limited, way. Furthermore, we show that a solar heading indicator, when used on a sufficiently short timescale, need not require time compensation at all. Finally, we suggest that solar-derived cues, such as shadows, could also be involved in navigation in ways that depend explicitly upon position, and are therefore not strictly compass-related. This could include giving directionality to landmarks, or acting as time-dependent landmarks involved in place recognition. We conclude that clock shift experiments alone are neither necessary nor sufficient to identify the occurrence of all conceivable uses of solar information in animal orientation, so that a predictable response to clock shift should not be regarded as an acid test of the use of solar information in navigation. PMID:25389374

  16. The sun compass revisited

    PubMed Central

    Guilford, Tim; Taylor, Graham K.

    2014-01-01

    Many animals, and birds in particular, are thought to use directional information from the sun in the form of a time-compensated sun compass, with predictably deviated orientation under clock shift being regarded as the litmus test of this. We suggest that this paradigm obscures a number of other ways in which solar-derived information could be important in animal orientation. We distinguish between the known use of the sun's azimuth to provide absolute geographical direction (compass mechanism) and its possible use to detect changes in heading (heading indicator mechanism). Just as in an aircraft, these two kinds of information may be provided by separate mechanisms and used for different functions, for example for navigation versus steering. We also argue that although a solar compass must be time-referenced to account for the sun's apparent diurnal movement, this need not entail full time compensation. This is because animals might also use time-dependent solar information in an associatively acquired, and hence time-limited, way. Furthermore, we show that a solar heading indicator, when used on a sufficiently short timescale, need not require time compensation at all. Finally, we suggest that solar-derived cues, such as shadows, could also be involved in navigation in ways that depend explicitly upon position, and are therefore not strictly compass-related. This could include giving directionality to landmarks, or acting as time-dependent landmarks involved in place recognition. We conclude that clock shift experiments alone are neither necessary nor sufficient to identify the occurrence of all conceivable uses of solar information in animal orientation, so that a predictable response to clock shift should not be regarded as an acid test of the use of solar information in navigation. PMID:25389374

  17. Finding Your Way with Map and Compass

    NSDL National Science Digital Library

    2001-03-01

    This U.S. Geological Survey fact sheet introduces topographic maps and explains how scale is used in a map to convey distance, how direction is determined using a compass, and how to use both a map and compass together by taking a compass bearing from a map. Contacts are provided to obtain current and historical magnetic declination information for any place in the United States.

  18. COMPASS: A probabilistic indoor positioning system based on 802.11 and digital compasses

    Microsoft Academic Search

    Thomas King; Stephan Kopf; Thomas Haenselmann; Christian Lubberger; Wolfgang Effelsberg

    2006-01-01

    ABSTRACT Positioning systems,are one,of the key elements,required by context-aware application and location-based services. This paper presents the design, implementation and anaylsis of a positioning system called COMPASS which is based on 802.11 compliant net- work infrastructure and digital compasses. On the mobile device, COMPASS samples the signal strength values of different access points in communication,range and utilizes the orientation of

  19. Compass and Kitaev models -- Theory and Physical Motivations

    E-print Network

    Zohar Nussinov; Jeroen van den Brink

    2013-03-24

    Compass models are theories of matter in which the couplings between the internal spin (or other relevant field) components are inherently spatially (typically, direction) dependent. Compass-type interactions appear in diverse physical systems including Mott insulators with orbital degrees of freedom (where interactions sensitively depend on the spatial orientation of the orbitals involved), the low energy effective theories of frustrated quantum magnets, systems with strong spin-orbit couplings (such as the iridates), vacancy centers, and cold atomic gases. Kitaev's models, in particular the compass variant on the honeycomb lattice, realize basic notions of topological quantum computing. The fundamental inter-dependence between internal (spin, orbital, or other) and external (i.e., spatial) degrees of freedom which underlies compass models generally leads to very rich behaviors including the frustration of (semi-)classical ordered states on non-frustrated lattices and to enhanced quantum effects prompting, in certain cases, the appearance of zero temperature quantum spin liquids. As a consequence of these frustrations, new types of symmetries and their associated degeneracies may appear. These intermediate symmetries lie midway between the extremes of global symmetries and local gauge symmetries and lead to effective dimensional reductions. We review compass models in a unified manner, paying close attention to exact consequences of these symmetries, and to thermal and quantum fluctuations that stabilize orders via order out of disorder effects. We review non-trivial statistics and the appearance of topological quantum orders in compass systems in which, by virtue of their intermediate symmetry standard orders do not arise. This is complemented by a survey of numerical results. Where appropriate theoretical and experimental results are compared.

  20. Remotely readable fiber optic compass

    DOEpatents

    Migliori, Albert (Santa Fe, NM); Swift, Gregory W. (Los Alamos, NM); Garrett, Steven L. (Pebble Beach, CA)

    1986-01-01

    A remotely readable fiber optic compass. A sheet polarizer is affixed to a magnet rotatably mounted in a compass body, such that the polarizer rotates with the magnet. The optical axis of the sheet polarizer is preferably aligned with the north-south axis of the magnet. A single excitation light beam is divided into four identical beams, two of which are passed through the sheet polarizer and through two fixed polarizing sheets which have their optical axes at right angles to one another. The angle of the compass magnet with respect to a fixed axis of the compass body can be determined by measuring the ratio of the intensities of the two light beams. The remaining ambiguity as to which of the four possible quadrants the magnet is pointing to is resolved by the second pair of light beams, which are passed through the sheet polarizer at positions which are transected by two semicircular opaque strips formed on the sheet polarizer. The incoming excitation beam and the four return beams are communicated by means of optical fibers, giving a remotely readable compass which has no electrical parts.

  1. Context Compass

    Microsoft Academic Search

    Riku Suomela; Juha Lehikoinen

    2000-01-01

    We present an easy and natural method for accessing contextual data shown on an electronic map in a wearable computer. The information is stored as virtual objects in a known network database. The objects are retrieved from a point of interest database and visualized on a head-worn display of a wearable computer. Our method uses the familiar compass metaphor to

  2. The development of migratory orientation mechanisms.

    PubMed

    Able, K P

    1991-01-01

    Recent experimental studies (since ca. 1985) on the ontogeny of orientation mechanisms in migratory birds are reviewed. The processes and interactions are synthesized into a framework that may help identify critical research questions. Birds that grow up in the earth's magnetic field develop the ability to perform appropriate migratory orientation, even in the absence of any experience with relevant visual cues. In two species, large changes in direction during the course of migration seem to be controlled by an endogenous time program. In one of these, the Pied Flycatcher (Ficedula hypoleuca), the correct magnetic orientation seems to occur only when the magnetic fields appropriate to the latitudes encountered en route were experienced at the proper seasonal time. The magnetic compass may be modified by visual experience with either the day or night sky. Celestial rotation may be the calibrating reference in this case, as it is in the development of the star compass. Young Savannah Sparrows (Passerculus sandwichensis) learn to perform compass orientation at sunset based on polarized skylight. This compass capability seems to be calibrated by magnetic directions. Some problems of experimental design and the interpretation of results from experiments on development are discussed. PMID:1838514

  3. Create a Compass

    NSDL National Science Digital Library

    2012-06-26

    In this activity, learners use simple materials to build their own compass. This resource contains information about compasses as well as suggestions on how learners can try out their home-made compasses in their lives.

  4. The cricket compass for context-aware mobile applications

    Microsoft Academic Search

    Nissanka B. Priyantha; Allen K. L. Miu; Hari Balakrishnan; Seth J. Teller

    2001-01-01

    The ability to determine the orientation of a device is of fundamental importance in context aware and location-dependent mobile computing. By analogy to a traditional compass, knowledge of orientation through the Cricket compass attached to a mobile device enhances various applications, including efficient way-finding and navigation, directional service discovery, and “augmented-reality” displays. Our compass infrastructure enhances the spatial inference capability

  5. Control of magnetization reversal in oriented strontium ferrite thin films

    SciTech Connect

    Roy, Debangsu, E-mail: debangsu@physics.iisc.ernet.in; Anil Kumar, P. S. [Department of Physics, Indian Institute of Science, Bangalore 560012 (India)

    2014-02-21

    Oriented Strontium Ferrite films with the c axis orientation were deposited with varying oxygen partial pressure on Al{sub 2}O{sub 3}(0001) substrate using Pulsed Laser Deposition technique. The angle dependent magnetic hysteresis, remanent coercivity, and temperature dependent coercivity had been employed to understand the magnetization reversal of these films. It was found that the Strontium Ferrite thin film grown at lower (higher) oxygen partial pressure shows Stoner-Wohlfarth type (Kondorsky like) reversal. The relative importance of pinning and nucleation processes during magnetization reversal is used to explain the type of the magnetization reversal with different oxygen partial pressure during growth.

  6. Cascade of period doubling bifurcations and large stochasticity in the motions of a compass (*)

    E-print Network

    Boyer, Edmond

    L-537 Cascade of period doubling bifurcations and large stochasticity in the motions of a compass, consisting of a compass placed in a periodic oscillating field, which renders the observation oflarge scale a compass, initially neglecting friction, in an oscillating magnetic field, perpendicular to the compass

  7. Magnetostatic wave propagation in a multilayered magnetic structure with an arbitrary orientation between the static magnetizations

    Microsoft Academic Search

    Kunquan Sun; Sonny Bolls

    1992-01-01

    The authors study magnetostatic wave propagation (MSW) in multilayered magnetic structure (YIG\\/GGG\\/YIG\\/GGG), in which the static magnetizations in the two magnetic layers are not colinear. It is assumed that there exists an arbitrary angle ? between the two magnetizations for a given applied DC field. Therefore, the effect of the relative orientation between the two magnetizations in two different YIG

  8. Magnetic orientation of snow buntings (Plectrophenax nivalis), a species breeding in the high Arctic: passage migration through temperate-zone areas

    PubMed

    Sandberg; Pettersson

    1996-01-01

    Orientation tests were conducted with snow buntings (Plectrophenax nivalis) exposed to artificially manipulated magnetic fields, during both spring and autumn migration. Experiments were run under clear sunset skies and under simulated complete overcast. The birds closely followed experimental shifts of the magnetic fields during both seasons regardless of whether they had access to celestial cues. Clear-sky tests in vertical magnetic fields resulted in a significant bimodal orientation, the directionality of which was almost identical during spring and autumn. When the snow buntings were deprived of celestial directional information and tested in vertical magnetic fields, they failed to show any statistically significant mean directions in either spring or autumn. The results demonstrate that snow buntings possess a magnetic compass and suggest that magnetic cues are of primary importance for their migratory orientation while on passage through temperate-zone areas. However, the axial orientation in vertical magnetic fields under clear skies may indicate an involvement of celestial cues as an auxiliary source of directional information. PMID:9319809

  9. Magnetic Position and Orientation Tracking System

    Microsoft Academic Search

    Frederick Raab; Ernest Blood; Terry Steiner; Herbert Jones

    1979-01-01

    Three-axis generation and sensing of quasi-static magneticdipole fields provide information sufficient to determine both the position and orientation of the sensor relative to the source. Linear rotation transformations based upon the previous measurements are applied to both the source excitation and sensor output vectors, yielding quantities that are linearly propotional to small changes in the position and orientation. Changes are

  10. A compass without a map: tortuosity and orientation of eastern painted turtles ( Chrysemys picta picta ) released in unfamiliar territory

    Microsoft Academic Search

    I. R. Caldwell; V. O. Nams

    2006-01-01

    Orientation mechanisms allow animals to spend minimal time in hostile areas while reaching needed resources. Identification of the specific mechanism used by an animal can be difficult, but examining an animal's path in familiar and unfamiliar areas can provide clues to the type of mechanism in use. Semiaquatic turtles are known to use a homing mechanism in familiar territory to

  11. The Orientation of the Local Interstellar Magnetic Field

    E-print Network

    M. Opher; E. C. Stone; T. I. Gombosi

    2007-05-13

    The orientation of the local interstellar magnetic field introduces asymmetries in the heliosphere that affect the location of heliospheric radio emissions and the streaming direction of ions from the termination shock of the solar wind. We combine observations of radio emissions and energetic particle streaming with extensive 3D MHD computer simulations of magnetic field draping over the heliopause to show that the plane of the local interstellar field is ~ 60-90 degrees from the galactic plane. This suggests that the field orientation in the Local Interstellar Cloud differs from that of a larger scale interstellar magnetic field thought to parallel the galactic plane.

  12. Condensation, demixing, and orientational ordering of magnetic colloidal suspensions

    NASA Astrophysics Data System (ADS)

    Cattes, Stefanie M.; Klapp, Sabine H. L.; Schoen, Martin

    2015-05-01

    In this work we study the phase behavior of magnetic particles suspended in a simple nonmagnetic solvent. Magnetic particles are modelled as spherical particles carrying a three-dimensional, classical Heisenberg spin, whereas solvent molecules are treated as spherically symmetric Lennard-Jones particles. The binary mixture of magnetic particles and solvent is studied within the framework of classical density functional theory (DFT). Within DFT pair correlations are treated at the modified mean-field level at which they are approximated by orientation dependent Mayer f functions. In the absence of an external magnetic field four generic types of phase diagrams are observed depending on the concentration of magnetic particles. In this case we observe liquid-liquid phase coexistence between an orientationally ordered (polarized) and a disordered phase characterized by slightly different concentrations of magnetic particles. Liquid-liquid phase coexistence is suppressed by an external field and vanishes completely if the strength of the field is sufficiently large.

  13. Orientational and Magnetic Behavior of a Colloidal Magnetic Suspension in a Cholesteric Liquid Crystal Matrix

    Microsoft Academic Search

    A. N. Zakhlevnykh; P. A. Sosnin

    1994-01-01

    Orientational and magnetic properties of a ferrocholesteric, i.e. highly dispersed magnetic suspension in a cholesteric liquid crystal matrix in a magnetic field which is perpendicular to the spiral axes is considered. Two mechanisms of the field influence on the ferrocholesteric art taken into account: the dipolar one due to the interaction between the field and the magnetic moments of the

  14. Compassion fatigue in nurses

    Microsoft Academic Search

    Elizabeth A. Yoder

    2010-01-01

    Compassion fatigue, trigger situations, and coping strategies were investigated in hospital and home care nurses. The Professional Quality of Life Scale measured compassion fatigue, compassion satisfaction, and burnout. Narrative questions elicited trigger situations and coping strategies. Compassion fatigue scores were significantly different between nurses who worked 8- or 12-hour shifts. Fifteen percent of the participants had scores indicating risk of

  15. Do leaf-cutter ants orient their path-integrated, home vector with a magnetic compass?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leaf-cutter ants Atta colombica forage over 250 m in structurally-complex, Neotropical rainforests that occlude sun or polarized light cues. Night foraging makes the use of celestial cues and landmarks all the more difficult. Typically leaf-cutter ants follow architecturally-modified, pheromonally-m...

  16. Aircraft compass characteristics

    NASA Technical Reports Server (NTRS)

    Peterson, John B; Smith, Clyde W

    1937-01-01

    A description of the test methods used at the National Bureau of Standards for determining the characteristics of aircraft compasses is given. The methods described are particularly applicable to compasses in which mineral oil is used as the damping liquid. Data on the viscosity and density of certain mineral oils used in United States Navy aircraft compasses are presented. Characteristics of Navy aircraft compasses IV to IX and some other compasses are shown for the range of temperatures experienced in flight. Results of flight tests are presented. These results indicate that the characteristic most desired in a steering compass is a short period and, in a check compass, a low overswing.

  17. From Compass to Hard Drive--Integrated Activities for Studying Magnets

    ERIC Educational Resources Information Center

    Dean, J.; Allwood, D. A.

    2014-01-01

    We describe a range of practical activities that allows students to investigate the properties and applications of magnets. The activities can be used in isolation or used together to build a rounded understanding of the subject area. The activities include simple demonstrations using common or inexpensive equipment, hands-on experiments for small…

  18. COMPASS Overview

    SciTech Connect

    Magnon, A. [DSM/DAPNIA/SPhN, CEA Saclay, F91191 Gif-sur-Yvette (France)

    2007-06-13

    The COMPASS experiment at CERN SPS investigates several aspects of the nucleon spin structure using the high energy longitudinally polarised muon beam and a large polarised solid target providing longitudinal or transverse polarisations. Results obtained during the 3 years of running (2002-2004) with a 6LiD target are summarized. They concern the measurements of longitudinal double spin cross-section asymmetries for the inclusive DIS, for the production of high pT hadron pairs and D mesons (direct determination of {delta}G/G), the measurements of Collins and Sivers asymmetries with a tranversely polarised target, the measurements of transverse and longitudinal polarisations for produced Lambda.

  19. Finding Your Way with Map and Compass

    NSDL National Science Digital Library

    This tutorial introduces students to the concept of navigating with a topographic map and compass. Topics include the features and symbols used on U. S. Geological Survey (USGS) maps, the use of scale to represent distance, and how to determine direction with a magnetic compass. There is also information on the scales and areas represented on various USGS maps and on how to compensate for magnetic declination.

  20. From compass to hard drive—integrated activities for studying magnets

    NASA Astrophysics Data System (ADS)

    Dean, J.; Allwood, D. A.

    2014-11-01

    We describe a range of practical activities that allows students to investigate the properties and applications of magnets. The activities can be used in isolation or used together to build a rounded understanding of the subject area. The activities include simple demonstrations using common or inexpensive equipment, hands-on experiments for small groups, and interactive problem solving suitable for whole classes. These can be tailored for students in either primary or secondary education.

  1. Hybrid Meson Structure at COMPASS

    E-print Network

    Murray Moinester; Suh Urk Chung

    2000-03-07

    We describe a pion physics program attainable with the CERN COMPASS spectrometer, involving tracking detectors and an electromagnetic calorimeter. COMPASS can realize state-of-the-art pion beam hybrid meson and meson radiative transition studies. We review here the physics motivation for this program. We describe the beam, detector, trigger requirements, and hardware/software requirements for this program. The triggers for all this hybrid meson physics can be implemented for simultaneous data taking. We will investigate hybrid meson production via pion-photon Primakoff and pion-Pomeron diffractive interactions. We will determine new properties of quark-antiquark-gluon hybrid mesons, using unique production methods, to improve our understanding of these exotic mesons. The CERN COMPASS experiment uses 100-280 GeV beams (muon, pion), and magnetic spectrometers and calorimeters, to measure the complete kinematics of pion-photon and pion-Pomeron reactions. The COMPASS experiment is currently under construction, and scheduled to begin data runs in 2001. We carry out simulation studies to optimize the beam, detector, trigger, and hardware/software for achieving high statistics data with low systematic uncertainties in the hybrid meson component of this program. We will improve previous Primakoff Hybrid studies by three orders of magnitude. We implement special detectors and triggers for hybrid meson production reactions. We propose to prepare for these COMPASS pion beam hybrid studies by setting up with muon beam tests.

  2. Bird orientation at high latitudes: flight routes between Siberia and North America across the Arctic Ocean

    PubMed

    Alerstam; Gudmundsson

    1999-12-22

    Bird migration and orientation at high latitudes are of special interest because of the difficulties associated with different compass systems in polar areas and because of the considerable differences between flight routes conforming to loxodromes (rhumblines) or orthodromes (great circle routes). Regular and widespread east-north-east migration of birds from the northern tundra of Siberia towards North America across the Arctic Ocean (without landmark influences) were recorded by ship-based tracking radar studies in July and August. Field observations indicated that waders, including species such as Phalaropusfulicarius and Calidris melanotos, dominated, but also terns and skuas may have been involved. Analysis of flight directions in relation to the wind showed that these movements are not caused by wind drift. Assuming possible orientation principles based on celestial or geomagnetic cues, different flight trajectories across the Arctic Ocean were calculated: geographical loxodromes, sun compass routes, magnetic loxodromes and magnetoclinic routes. The probabilities of these four alternatives are evaluated on the basis of both the availability of required orientation cues and the predicted flight paths. This evaluation supports orientation along sun compass routes. Because of the longitudinal time displacement sun compass routes show gradually changing compass courses in close agreement with orthodromes. It is suggested that an important migration link between Siberia and North American stopover sites 1000-2500km apart across the Arctic Ocean has evolved based on sun compass orientation along orthodrome-like routes. PMID:10693821

  3. Neural basis of the magnetic compass: interactions of visual, magnetic and vestibular inputs in the pigeon's brain

    Microsoft Academic Search

    P. Semm; D. Nohr; C. Demaine; W. Wiltschko

    1984-01-01

    Single unit electrical activity was recorded extracellularly in the lateral and superior vestibular nuclei, the vestibulo-cerebellum and the nucleus of the basal optic root (nBOR) under earth-strength magnetic stimulation. Units in the vestibular system responded with either inhibition or excitation to the magnetic stimuli only if the animal was moved out of the horizontal plane. No responses to the artificial

  4. Magnetic orientation of fine particles in composite materials

    Microsoft Academic Search

    D. M. Karpinos; G. I. Yaglo; L. M. Aplninskaya; N. F. Efremova; Yu. A. Maksimenko

    1982-01-01

    This difficulty can be overcome by coating such particles or fibers with a ferromagnetic material. The aim here must be to apply uniform coatings enabling particles and fibers to Orient themselves in comparatively weak magnetic fields without at the same time affecting any of the properties of the starting material. In this connection, the work described in this paper was

  5. Accurate Orientation Estimation Using AHRS under Conditions of Magnetic Distortion

    PubMed Central

    Yadav, Nagesh; Bleakley, Chris

    2014-01-01

    Low cost, compact attitude heading reference systems (AHRS) are now being used to track human body movements in indoor environments by estimation of the 3D orientation of body segments. In many of these systems, heading estimation is achieved by monitoring the strength of the Earth's magnetic field. However, the Earth's magnetic field can be locally distorted due to the proximity of ferrous and/or magnetic objects. Herein, we propose a novel method for accurate 3D orientation estimation using an AHRS, comprised of an accelerometer, gyroscope and magnetometer, under conditions of magnetic field distortion. The system performs online detection and compensation for magnetic disturbances, due to, for example, the presence of ferrous objects. The magnetic distortions are detected by exploiting variations in magnetic dip angle, relative to the gravity vector, and in magnetic strength. We investigate and show the advantages of using both magnetic strength and magnetic dip angle for detecting the presence of magnetic distortions. The correction method is based on a particle filter, which performs the correction using an adaptive cost function and by adapting the variance during particle resampling, so as to place more emphasis on the results of dead reckoning of the gyroscope measurements and less on the magnetometer readings. The proposed method was tested in an indoor environment in the presence of various magnetic distortions and under various accelerations (up to 3 g). In the experiments, the proposed algorithm achieves <2° static peak-to-peak error and <5° dynamic peak-to-peak error, significantly outperforming previous methods. PMID:25347584

  6. Accurate orientation estimation using AHRS under conditions of magnetic distortion.

    PubMed

    Yadav, Nagesh; Bleakley, Chris

    2014-01-01

    Low cost, compact attitude heading reference systems (AHRS) are now being used to track human body movements in indoor environments by estimation of the 3D orientation of body segments. In many of these systems, heading estimation is achieved by monitoring the strength of the Earth's magnetic field. However, the Earth's magnetic field can be locally distorted due to the proximity of ferrous and/or magnetic objects. Herein, we propose a novel method for accurate 3D orientation estimation using an AHRS, comprised of an accelerometer, gyroscope and magnetometer, under conditions of magnetic field distortion. The system performs online detection and compensation for magnetic disturbances, due to, for example, the presence of ferrous objects. The magnetic distortions are detected by exploiting variations in magnetic dip angle, relative to the gravity vector, and in magnetic strength. We investigate and show the advantages of using both magnetic strength and magnetic dip angle for detecting the presence of magnetic distortions. The correction method is based on a particle filter, which performs the correction using an adaptive cost function and by adapting the variance during particle resampling, so as to place more emphasis on the results of dead reckoning of the gyroscope measurements and less on the magnetometer readings. The proposed method was tested in an indoor environment in the presence of various magnetic distortions and under various accelerations (up to 3 g). In the experiments, the proposed algorithm achieves <2° static peak-to-peak error and <5° dynamic peak-to-peak error, significantly outperforming previous methods. PMID:25347584

  7. Magnetorheological effect in the magnetic field oriented along the vorticity

    SciTech Connect

    Kuzhir, P., E-mail: pavel.kuzhir@unice.fr; Magnet, C.; Fezai, H.; Meunier, A.; Bossis, G. [Laboratory of Condensed Matter Physics, CNRS UMR7336, University of Nice-Sophia Antipolis, 28 Avenue Joseph Vallot, 06100 Nice (France); Rodríguez-Arco, L.; López-López, M. T. [Department of Applied Physics, University of Granada, Campus de Fuentenueva, 18071 Granada (Spain); Zubarev, A. [Department of Mathematical Physics, Ural Federal University, 51 Prospekt Lenina, 620083 Ekaterinburg (Russian Federation)

    2014-11-01

    In this work, we have studied the magnetorheological (MR) fluid rheology in the magnetic field parallel to the fluid vorticity. Experimentally, the MR fluid flow was realized in the Couette coaxial cylinder geometry with the magnetic field parallel to the symmetry axis. The rheological measurements were compared to those obtained in the cone-plate geometry with the magnetic field perpendicular to the lower rheometer plate. Experiments revealed a quasi-Bingham behavior in both geometries with the stress level being just a few dozens of percent smaller in the Couette cylindrical geometry at the same internal magnetic field. The unexpectedly high MR response in the magnetic field parallel to the fluid vorticity is explained by stochastic fluctuations of positions and orientations of the particle aggregates. These fluctuations are induced by magnetic interactions between them. Once misaligned from the vorticity direction, the aggregates generate a high stress independent of the shear rate, and thus assimilated to the suspension apparent (dynamic) yield stress. Quantitatively, the fluctuations of the aggregate orientation are modeled as a rotary diffusion process with a diffusion constant proportional to the mean square interaction torque. The model gives a satisfactory agreement with the experimental field dependency of the apparent yield stress and confirms the nearly quadratic concentration dependency ?{sub Y}??{sup 2.2}, revealed in experiments. The practical interest of this study lies in the development of MR smart devices with the magnetic field nonperpendicular to the channel walls.

  8. Sun compass error model

    NASA Technical Reports Server (NTRS)

    Blucker, T. J.; Ferry, W. W.

    1971-01-01

    An error model is described for the Apollo 15 sun compass, a contingency navigational device. Field test data are presented along with significant results of the test. The errors reported include a random error resulting from tilt in leveling the sun compass, a random error because of observer sighting inaccuracies, a bias error because of mean tilt in compass leveling, a bias error in the sun compass itself, and a bias error because the device is leveled to the local terrain slope.

  9. Magnetic anisotropy and organization of nanoparticles in heads and antennae of neotropical leaf-cutter ants, Atta colombica

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oriented magnetic nanoparticles have been suggested as a good candidate for a magnetic sensor in ants. Behavioral evidence for a magnetic compass in Neotropical leafcutter ants, Atta colombica (Formicidae: Attini), motivated a study of the arrangement of magnetic particles in the ants’ four major bo...

  10. FEA Simulations of Magnets with Grain Oriented Steel

    SciTech Connect

    Witte H.

    2012-08-06

    One of the potential successors of the Large Hadron Collider is a Muon Col- lider. Muons are short-lived particles, which therefore require fast acceleration. One potential avenue is a very fast cycling cyclotron, where the bending is sup- plied by a combination of fixed-field superconducting magnets and fast ramping normal conducting iron-cored coils. Due to the high ramping rate (around 1 kHz) eddy current and hysteresis losses are a concern. One way to overcome these is by using grain-oriented soft-iron, which promises superior magnetic properties in the direction of the grains. This note summarizes efforts to include the anisotropic material properties of grain-oriented steel in finite element analysis to predict the behaviour of the dipole magnets for this accelerator. It was found that including anisotropic material properties has a detrimental effect on model convergence. During this study it was not possible to include grain oriented steel with an accuracy necessary to study the field quality of a dipole magnet.

  11. Chromophore Orientation in Bacteriorhodopsin Determined from the Angular Dependence of Deuterium Nuclear Magnetic Resonance Spectra of Oriented Purple

    E-print Network

    Brown, Michael F.

    Chromophore Orientation in Bacteriorhodopsin Determined from the Angular Dependence of Deuterium Nuclear Magnetic Resonance Spectra of Oriented Purple Membranes Stephan Moltke, Alexander A. NevzorovVed March 24, 1998 ABSTRACT: The orientation of prosthetic groups in membrane proteins is of considerable

  12. Foundations and Light Compass Foundations and Light Compass

    E-print Network

    Wong, Jennifer L.

    Foundations and Light Compass Case Study Foundations and Light Compass Case Study Jennifer L. WongQuantitative Sensor--centric Designcentric Design Light CompassLight Compass ­­ Models and Abstractions Contaminant Transport Marine Microorganisms Ecosystems, Biocomplexity What is a Light Compass?What is a Light

  13. Orientation dependence of magnetization transfer parameters in human white matter.

    PubMed

    Pampel, André; Müller, Dirk K; Anwander, Alfred; Marschner, Henrik; Möller, Harald E

    2015-07-01

    Quantification of magnetization-transfer (MT) experiments is typically based on a model comprising a liquid pool "a" of free water and a semisolid pool "b" of motionally restricted macromolecules or membrane compounds. By a comprehensive fitting approach, high quality MT parameter maps of the human brain are obtained. In particular, a distinct correlation between the diffusion-tensor orientation with respect to the B0-magnetic field and the apparent transverse relaxation time, T2(b), of the semisolid pool (i.e., the width of its absorption line) is observed. This orientation dependence is quantitatively explained by a refined dipolar lineshape for pool b that explicitly considers the specific geometrical arrangement of lipid bilayers wrapped around a cylindrical axon. The model inherently reduces the myelin membrane to its lipid constituents, which is motivated by previous studies on efficient interaction sites (e.g., cholesterol or galactocerebrosides) in the myelin membrane and on the origin of ultrashort T2 signals in cerebral white matter. The agreement between MT orientation effects and corresponding forward simulations using empirical diffusion imaging results as input as well as results from fits employing the novel lineshape support previous suggestions that the fiber orientation distribution in a voxel can be modeled as a scaled Bingham distribution. PMID:25862261

  14. Video Compass

    Microsoft Academic Search

    Jana Kosecká; Wei Zhang

    2002-01-01

    In this paper we describe a flexible approach for determin- ing the relative orientation of the camera with respect to the scene. The main premise of the approach is the fact that in man-made environments, the majority of lines is aligned with the principal orthogonal directions of the world coordinate frame. We exploit this observation towards e- cient detection and

  15. Perceptual strategies of pigeons to detect a rotational centre--a hint for star compass learning?

    PubMed

    Alert, Bianca; Michalik, Andreas; Helduser, Sascha; Mouritsen, Henrik; Güntürkün, Onur

    2015-01-01

    Birds can rely on a variety of cues for orientation during migration and homing. Celestial rotation provides the key information for the development of a functioning star and/or sun compass. This celestial compass seems to be the primary reference for calibrating the other orientation systems including the magnetic compass. Thus, detection of the celestial rotational axis is crucial for bird orientation. Here, we use operant conditioning to demonstrate that homing pigeons can principally learn to detect a rotational centre in a rotating dot pattern and we examine their behavioural response strategies in a series of experiments. Initially, most pigeons applied a strategy based on local stimulus information such as movement characteristics of single dots. One pigeon seemed to immediately ignore eccentric stationary dots. After special training, all pigeons could shift their attention to more global cues, which implies that pigeons can learn the concept of a rotational axis. In our experiments, the ability to precisely locate the rotational centre was strongly dependent on the rotational velocity of the dot pattern and it crashed at velocities that were still much faster than natural celestial rotation. We therefore suggest that the axis of the very slow, natural, celestial rotation could be perceived by birds through the movement itself, but that a time-delayed pattern comparison should also be considered as a very likely alternative strategy. PMID:25807499

  16. Color Edge Detection with the Compass Operator

    Microsoft Academic Search

    Mark A. Ruzon; Carlo Tomasi

    1999-01-01

    The compass operator detects step edges without as- suming that the regions on either side have constant color. Using distributions of pixel colors rather than the mean, the operator finds the orientation of a diameter that maximizes the difference between two halves of a circular window. Junctions can also be detected by exploiting their lack of bilateral symmetry. This approach

  17. Testing avian compass calibration: comparative experiments with diurnal and nocturnal passerine migrants in South Sweden

    PubMed Central

    Åkesson, Susanne; Odin, Catharina; Hegedüs, Ramón; Ilieva, Mihaela; Sjöholm, Christoffer; Farkas, Alexandra; Horváth, Gábor

    2015-01-01

    ABSTRACT Cue-conflict experiments were performed to study the compass calibration of one predominantly diurnal migrant, the dunnock (Prunella modularis), and two species of nocturnal passerine migrants, the sedge warbler (Acrocephalus schoenobaenus), and the European robin (Erithacus rubecula) during autumn migration in South Sweden. The birds' orientation was recorded in circular cages under natural clear and simulated overcast skies in the local geomagnetic field, and thereafter the birds were exposed to a cue-conflict situation where the horizontal component of the magnetic field (mN) was shifted +90° or ?90° at two occasions, one session starting shortly after sunrise and the other ca. 90?min before sunset and lasting for 60?min. The patterns of the degree and angle of skylight polarization were measured by full-sky imaging polarimetry during the cue-conflict exposures and orientation tests. All species showed orientation both under clear and overcast skies that correlated with the expected migratory orientation towards southwest to south. For the European robin the orientation under clear skies was significantly different from that recorded under overcast skies, showing a tendency that the orientation under clear skies was influenced by the position of the Sun at sunset resulting in more westerly orientation. This sun attraction was not observed for the sedge warbler and the dunnock, both orientating south. All species showed similar orientation after the cue-conflict as compared to the preferred orientation recorded before the cue-conflict, with the clearest results in the European robin and thus, the results did not support recalibration of the celestial nor the magnetic compasses as a result of the cue-conflict exposure. PMID:25505150

  18. Testing avian compass calibration: comparative experiments with diurnal and nocturnal passerine migrants in South Sweden.

    PubMed

    Åkesson, Susanne; Odin, Catharina; Hegedüs, Ramón; Ilieva, Mihaela; Sjöholm, Christoffer; Farkas, Alexandra; Horváth, Gábor

    2014-01-01

    Cue-conflict experiments were performed to study the compass calibration of one predominantly diurnal migrant, the dunnock (Prunella modularis), and two species of nocturnal passerine migrants, the sedge warbler (Acrocephalus schoenobaenus), and the European robin (Erithacus rubecula) during autumn migration in South Sweden. The birds' orientation was recorded in circular cages under natural clear and simulated overcast skies in the local geomagnetic field, and thereafter the birds were exposed to a cue-conflict situation where the horizontal component of the magnetic field (mN) was shifted +90° or -90° at two occasions, one session starting shortly after sunrise and the other ca. 90?min before sunset and lasting for 60?min. The patterns of the degree and angle of skylight polarization were measured by full-sky imaging polarimetry during the cue-conflict exposures and orientation tests. All species showed orientation both under clear and overcast skies that correlated with the expected migratory orientation towards southwest to south. For the European robin the orientation under clear skies was significantly different from that recorded under overcast skies, showing a tendency that the orientation under clear skies was influenced by the position of the Sun at sunset resulting in more westerly orientation. This sun attraction was not observed for the sedge warbler and the dunnock, both orientating south. All species showed similar orientation after the cue-conflict as compared to the preferred orientation recorded before the cue-conflict, with the clearest results in the European robin and thus, the results did not support recalibration of the celestial nor the magnetic compasses as a result of the cue-conflict exposure. PMID:25505150

  19. Distributed scheduling with COMPASS

    NASA Technical Reports Server (NTRS)

    Rufat-Latre, Jorge; Culbert, Chris

    1991-01-01

    COMPASS (COMPuter Aided Scheduling System) is a sophisticated, interactive scheduling tool used within NASA. Like most existing tools, however, COMPASS is a single-user application. There is a large class of scheduling problems which may be better solved by allowing several people at various locations to build separate schedules with shared resources. DISCORS (DIStributed COmputer Resource Scheduling) is a set of services which support a distributed version of COMPASS. This architecture naturally accommodates the integration of user-defined resource models without modifying COMPASS. DISCORS services include the ability to establish and manage communications, to code messages in efficient formats, to provide fault detection and recovery, and to configure schedulers across a network. In its present form, DISCORS effectively supports distributed COMPASS, but fails to run fast and to guarantee efficient schedules. Further enhancements may allow several users to simultaneously and interactively work together to create complex schedules while COMPASS detects and coordinates the resolution of conflicting requests.

  20. Pigeon orientation: effects of the application of magnets under overcast skies

    NASA Astrophysics Data System (ADS)

    Ioalè, P.

    To verify the existence of a magnetic compass in birds, researchers have often released homing pigeons under overcast skies that are equipped with bar magnets on various parts of their body. In particular, Keeton was successful in finding disorientation in overcast conditions in a first series of tests, but not in a second series. The experiments reported here attempt to explain this contradiction on the basis of findings obtained by releasing pigeons equipped in a way similar to that reported in Keeton's tests and pigeons equipped in a way similar to that reported by other authors.

  1. Magnetic preferential orientation of metal oxide superconducting materials

    DOEpatents

    Capone, Donald W. (Bolingbrook, IL); Dunlap, Bobby D. (Bolingbrook, IL); Veal, Boyd W. (Downers Grove, IL)

    1990-01-01

    A superconductor comprised of a polycrystalline metal oxide such as YBa.sub.2 Cu.sub.3 O.sub.7-X (where 0magnetic field to orient the individual crystals when in the superconducting state to substantially increase current transport between adjacent grains. In another embodiment, the anisotropic paramagnetic susceptibility of rare-earth ions substituted into the oxide material is made use of as an applied magnetic field orients the particles in a preferential direction. This latter operation can be performed with the material in the normal (non-superconducting) state.

  2. COMPASS Results on Collins and Sivers Asymmetries

    E-print Network

    Andrea Bressan; for the COMPASS Collaboration

    2009-07-31

    In the list of the main items studied by the CERN COMPASS experiment there are the transverse spin and momentum effects visible in the azimuthal distributions of hadrons produced in the deep inelastic scattering. In the years 2002-2004 COMPASS has collected data with a 6LiD target with the polarization oriented transversely with respect to the muon beam direction for about 20% of the running time; in 2007, COMPASS has used for the first time a proton NH_3 target with the data taking time equally shared between longitudinal and transverse polarization of the target. After reviewing the results obtained with the deuteron, the new results for the Collins and Sivers asymmetries of the proton will be presented.

  3. The Enterprise Compass

    ERIC Educational Resources Information Center

    McCardle, Ken

    2005-01-01

    As a CIO leading an IT department through change and reorganization, the author developed the Enterprise Compass--a four-point guide to reaching goals and focusing achievement. The Enterprise Compass directs staff to look forward to future accomplishment, back for performance assessments, across campus for better understanding of practical working…

  4. Luminosity Measurement at COMPASS

    E-print Network

    C. Höppner for the COMPASS Collaboration

    2011-04-14

    The measurement of absolutely normalized cross sections for high-energy scattering processes is an important reference for theoretical models. This paper discusses the first determination of the luminosity for data of the COMPASS experiment, which is the basis for such measurements. The resulting normalization is validated via the determination of the structure function $F_2$ from COMPASS data, which is compared to literature.

  5. Compass Needles around a Simple Circuit

    NSDL National Science Digital Library

    2012-08-03

    This is an activity about electromagnetism. Learners will set up a simple circuit using a battery, wire, and knife switch, and then use a compass to map the magnetic field lines surrounding the wire. Next, they will add a coil of wire to the simple circuit and map the magnetic fields again. This is the second lesson in the second session of the Exploring Magnetism teachers guide.

  6. Defect induced magnetism in highly oriented pyrolytic graphite: bulk magnetization and 19F hyperfine interaction studies.

    PubMed

    Mohanta, S K; Mishra, S N; Davane, S M; Srivastava, S K

    2012-02-29

    We have made bulk and local investigations on defect induced magnetism in highly oriented pyrolytic graphite (HOPG) irradiated with a 40 MeV carbon beam. The local magnetic response of irradiated HOPG was studied by measuring the hyperfine field of recoil implanted (19)F using ?-ray time differential perturbed angular distribution (TDPAD) measurements. While the bulk magnetic properties of the irradiated sample show features characteristic of room temperature ferromagnetism, the hyperfine field data reflect enhanced paramagnetism with no indication of long range magnetic ordering. The experimental studies are further supported by ab initio density functional calculations. We believe that the ferromagnetic response in irradiated HOPG arises mostly from defect induced magnetic moments of carbon atoms in the near surface region, while those deep inside the host matrix remain paramagnetic. PMID:22277293

  7. Journal of Magnetism and Magnetic Materials 300 (2006) 127131 Electric current-induced spin orientation in quantum well structures

    E-print Network

    Ganichev, Sergey

    2006-01-01

    Journal of Magnetism and Magnetic Materials 300 (2006) 127­131 Electric current-induced spin is the orientation of spins by an electrical current flowing through low-dimensional carrier systems of sufficiently to orient the spin of charge carriers in GaAs based quantum wells (QWs) by driving an electric current

  8. Orientation and symmetry control of inverse sphere magnetic nanoarrays by guided self-assembly

    E-print Network

    Southampton, University of

    Orientation and symmetry control of inverse sphere magnetic nanoarrays by guided self on the Ni arrays were performed showing room temperature anisotropic magnetoresistance of 0 are very attractive for fundamental studies on magnetism and applications such as patterned storage media

  9. The Newly Upgraded Large COMPASS Polarized Target

    SciTech Connect

    Gautheron, F. [Physics department, University of Bielefeld, Bielefeld (Germany)

    2007-06-13

    During the CERN SPS 2005 shutdown the COMPASS target system received a major hardware upgrade for the new period of data taking starting in 2006. A new superconducting magnet with a larger acceptance combined with a new microwave cavity and a three cell target setup have been installed and already showed excellent performances that we present for the first time.

  10. Controlling the relative orientation between the two magnetic fields of a synchronous motor

    Microsoft Academic Search

    Sameb Refaat; Saeid Nahavandi

    2001-01-01

    A simple and reliable method for controlling the relative orientation between the two magnetic fields of a permanent magnet synchronous motor is presented. Finding the initial (at motor powering-up time) value of this relative location is essential for the proper operation of the motor. The feedback control loop used finds this initial relative orientation quickly. Further, using the proposed method

  11. Magnetic Fields

    NSDL National Science Digital Library

    2014-09-18

    Students visualize the magnetic field of a strong permanent magnet using a compass. The lesson begins with an analogy to the effect of the Earth's magnetic field on a compass. Students see the connection that the compass simply responds to the Earth's magnetic field since it is the closest, strongest field, and thus the compass responds to the field of the permanent magnets, allowing them the ability to map the field of that magnet in the activity. This information will be important in designing a solution to the grand challenge in activity 4 of the unit.

  12. COMPASS-II: COMPASS Future Programs

    SciTech Connect

    Doshita, Norihiro [Faculty of Science, Yamagata University, Kojirakawa-machi 1-4-12, Yamagata, 990-8560 (Japan); Collaboration: COMPASS Collaboration

    2011-12-14

    The COMPASS (COmmon Muon and Proton apparatus for Structure and Spectroscopy) experiment started more than 10 years ago and has published many results concerning nucleon structure and hadron spectroscopy. We propose additional measurements for a new fascinating QCD-related studies of nucleon structure and hadron spectroscopy with small modifications of the present apparatus, that includes either an unpolarized or polarized target.

  13. Magnetism of oriented single crystals of hemoilmenite with self-reversed thermoremanent magnetization

    Microsoft Academic Search

    Avto Goguitchaichvili; Michel Prévot

    2000-01-01

    Ten large, single crystals of hemoilmenite (yFeTiO3(1-y)Fe2O3) with y close to 0.54 were extracted from the self-reversed Pinatubo dacitic pumice erupted in 1991 and oriented with respect to the c axis of the hexagonal structure by means of an x-ray diffractometer. Hysteresis measurements show that c is the hardest magnetization axis while the softest axes lie in the basal plane.

  14. Magnetic properties of (1 1 0)- and (2 0 0)-oriented Fe-nanowire arrays

    Microsoft Academic Search

    H. N. Hu; H. Y. Chen; J. L. Chen; G. H. Wu

    2005-01-01

    Fe-nanowire arrays with (110) and (200) orientation have been fabricated through controlling the pH values in electrodeposition. Fe-nanowire arrays 30 and 60nm in diameter were obtained. With the magnetic field applied parallel to the wire, 60nm diameter Fe nanowires with preferred (200) orientation show an improved squareness and an easier magnetization than the nanowires with preferred (110) orientation. For 30nm

  15. Rapid Learning of Magnetic Compass Direction by C57BL/6 Mice in a 4-Armed `Plus' Water Maze

    E-print Network

    Phillips, John B.

    by two families of molerats, Siberian hamsters and C57BL/6 mice. However, assays widely used to study mammals, bats [3,4], two families of subterranean molerats [5­7], as well as Siberian hamsters and C57BL/6 orientation in Siberian hamsters and C57BL/6

  16. Orientational behavior of phosphatidylcholine bilayers in the presence of aromatic amphiphiles and a magnetic field.

    PubMed Central

    Sanders, C R; Schaff, J E; Prestegard, J H

    1993-01-01

    A number of aromatic-containing additives which can influence the orientation of fragments of lipid bilayer membranes by a magnetic field have been investigated. Two properties of these additives prove important: (1) sufficient detergency to facilitate reorganization of bilayer components and (2), sufficient anisotropy in magnetic susceptibility the preferred direction of fragment orientation. Triton X-100 is identified as effective in terms of facilitating magnetic field ordering of bilayer fragments but does not alter the preferred direction of orientation. A combination of the detergent CHAPSO (3-[(3-cholamidopropyl)-dimethylammonio]-1-propane sulfonate) and the aromatic alcohol 1-naphthol facilitates both ordering and alters the preferred direction of bilayer orientation. As mixtures of dimyristoylphosphatidylcholine (DMPC) and CHAPSO, which orient with bilayer normals perpendicular to the magnetic field, were titrated with 1-naphthol, the assemblies underwent transitions, first to random orientation, and then to an orientation with bilayer normals parallel to the field. Based on temperature-induced phase transitions and the extent of motional averaging of the 31P shielding tensor of the DMPC headgroup, the DMPC in these oriented samples appears to maintain a bilayer morphology during transitions. The insight provided in this study regarding factors which influence fragment stability and orientation lays the groundwork for the design of improved field-oriented media for spectroscopic investigation of membrane components. PMID:8494971

  17. DMPC vesicles and mixed DMPC/C12E8 micelles orientation in strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Kiselev, M. A.; Janich, M.; Lesieur, P.; Hoell, A.; Oberdisse, J.; Pepy, G.; Kisselev, A. M.; Gapienko, I. V.; Gutberlet, T.; Aksenov, V. L.

    The orientation of dimyristoylphosphatidylcholine (DMPC) multilamellar vesicles below and close to the main phase transition and of DMPC/C12E8 mixed micelles in strong magnetic fields has been studied via small-angle neutron scattering at magnetic fields of 1-4 T. A partial deformation of the DMPC vesicles from spherical to ellipsoidal shape was observed even at low magnetic field (H=2T). The orientation of the polymer-like mixed micelles of DMPC/C12E8 in the magnetic field shows a Gaussian-coil behavior independent of the applied magnetic field strength.

  18. Two-stage magnetic orientation of uric acid crystals as gout initiators

    NASA Astrophysics Data System (ADS)

    Takeuchi, Y.; Miyashita, Y.; Mizukawa, Y.; Iwasaka, M.

    2014-01-01

    The present study focuses on the magnetic behavior of uric acid crystals, which are responsible for gout. Under a sub-Tesla (T)-level magnetic field, rotational motion of the crystals, which were caused by diamagnetic torque, was observed. We used horizontal magnetic fields with a maximum magnitude of 500 mT generated by an electromagnet to observe the magnetic orientation of the uric acid microcrystals by a microscope. The uric acid crystals showed a perpendicular magnetic field orientation with a minimum threshold of 130 mT. We speculate that the distinct diamagnetic anisotropy in the uric acid crystals resulted in their rotational responses.

  19. Quantum Correlation in One-dimensional Extend Quantum Compass Model

    E-print Network

    Wen-Long You

    2012-02-04

    We study the correlations in the one-dimensional extended quantum compass model in a transverse magnetic field. By exactly solving the Hamiltonian, we find that the quantum correlation of the ground state of one-dimensional quantum compass model is vanishing. We show that quantum discord can not only locate the quantum critical points, but also discern the orders of phase transitions. Furthermore, entanglement quantified by concurrence is also compared.

  20. Three-dimensional odor compass

    Microsoft Academic Search

    Hiroshi Ishida; Akito Kobayashi; Takamichi Nakamoto; Toyosaka Moriizumi

    1999-01-01

    A three-dimensional odor compass is proposed to develop a navigation tool used in searching for an odor source. The compass, which continuously points to the source, is equipped with four semiconductor gas sensors and a small fan to draw air to the sensors. The direction of the source is obtained by rotating the compass head to obtain the direction where

  1. A molecular compass for bird navigation

    NASA Astrophysics Data System (ADS)

    Hore, Peter

    2015-03-01

    Migratory birds travel spectacular distances, navigating and orienting by a variety of means, most of which are poorly understood. Among them is a remarkable ability to perceive the intensity and direction of the Earth's magnetic field. Biologically credible mechanisms for the sensing of such weak fields (25-65 microtesla) are scarce and in recent years just two proposals have emerged as frontrunners. One involves biogenic iron-containing nanoparticles; the other relies on the magnetic sensitivity of short-lived photochemical intermediates known as radical pairs. The latter began to attract attention following the proposal 15 years ago that the necessary physics and chemistry could take place in the bird's retina in specialised photoactive proteins called cryptochromes. The coherent dynamics of the electron-nuclear spin systems of pairs of photo-induced radicals is conjectured to form the basis of the sensing mechanism even though the interaction of an electron spin with the geomagnetic field is six orders of magnitude smaller than the thermal energy. The possibility that slowing decohering, entangled electron spins could form the basis of an important sensory mechanism has qualified radical pair magnetoreception for a place under the umbrella of ``Quantum Biology.'' In this talk, I will introduce the radical pair mechanism, comment on the roles of entanglement and quantum coherence, outline some of the experimental evidence for the cryptochrome hypothesis, and summarize what still needs to be done to determine whether birds (and maybe other animals) really do use a chemical compass to find their way around. This work was supported by grants from DARPA, AFOSR, ERC and the EMF Biological Research Trust.

  2. Effect of high magnetic fields on orientation and properties of liquid crystalline thermosets

    SciTech Connect

    Smith, M.E.; Benicewicz, B.C.; Douglas, D.P. [Los Alamos National Lab., NM (United States); Earls, J.D.; Priester, R.D. Jr. [Dow Chemical U.S.A., Freeport, TX (United States). Texas Div.

    1996-02-01

    In this report we provide the first description of the orientation of liquid crystalline thermosets (LCT`s) in field strengths of up to 18 T, as well as the first report of tensile properties for both unoriented and oriented LCT`S. The LCT we have chosen for study is the diglycidyl ether of dihydroxy-a-methylstilbene cured with the diamine, sulfanilamide. Orientation in magnetic fields leads to an increase of almost three times the modulus compared to the unoriented material. These values are much greater than can be obtained with conventional thermosets. The strain at break is also significantly affected by the chain orientation. The coefficient of thermal expansion and x-ray diffraction of oriented samples show high degrees of anisotropy, indicating significant chain alignment in the magnetic field. We are working to further understand the field dependence of orientation and properties plus the mechanisms of the alignment process.

  3. Resource representation in COMPASS

    NASA Technical Reports Server (NTRS)

    Fox, Barry R.

    1991-01-01

    A set of viewgraphs on resource representation in COMPASS is given. COMPASS is an incremental, interactive, non-chronological scheduler written in Ada with an X-windows user interface. Beginning with an empty schedule, activities are added to the schedule one at a time, taking into consideration the placement of the activities already on the timeline and the resources that have been reserved for them. The order that the activities are added to the timeline and their location on the timeline are controlled by selection and placement commands invoked by the user. The order that activities are added to the timeline and their location are independent. The COMPASS code library is a cost effective platform for the development of new scheduling applications. It can be effectively used off the shelf for compatible scheduling applications or it can be used as a parts library for the development of custom scheduling systems.

  4. Charter for Compassion

    NSDL National Science Digital Library

    The idea for the Charter for Compassion came from Karen Armstrong, who is a former Roman Catholic nun who left a British convent to pursue a degree in modern literature at Oxford. In 2008 she won the TED Prize, and as part of this prize she wished for help starting the Charter for Compassion. Essentially, the Charter is "a cooperative effort to restore not only compassionate thinking but, more importantly, compassionate action to the center of religious, moral and political life." Visitors to the site can read the Charter, and then add their name to the list of those who have affirmed its principles. On the site, visitors can also read reflections from people who have signed the Charter and also learn more about "Acts of Compassion" performed by various people around the world.

  5. Optical Orientation of Mn2+ Ions in GaAs in Weak Longitudinal Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Akimov, I. A.; Dzhioev, R. I.; Korenev, V. L.; Kusrayev, Yu. G.; Sapega, V. F.; Yakovlev, D. R.; Bayer, M.

    2011-04-01

    We report on optical orientation of Mn2+ ions in bulk GaAs subject to weak longitudinal magnetic fields (B?100mT). A manganese spin polarization of 25% is directly evaluated by using spin-flip Raman scattering. The dynamical Mn2+ polarization occurs due to the s-d exchange interaction with optically oriented conduction band electrons. Time-resolved photoluminescence reveals a nontrivial electron spin dynamics, where the oriented Mn2+ ions tend to stabilize the electron spins.

  6. Magnetic orientation of the Common Toad: establishing an arena approach for adult anurans

    Microsoft Academic Search

    Lukas Landler; Günter Gollmann

    2011-01-01

    Background  Magnetic orientation is a taxonomically widespread phenomenon in the animal kingdom, but has been little studied in anuran\\u000a amphibians. We collected Common Toads (Bufo bufo) during their migration towards their spawning pond and tested them shortly after displacement for possible magnetic orientation\\u000a in arena experiments. Animals were tested in two different set-ups, in the geomagnetic field and in a reversed

  7. Sensing Magnetic Directions in Birds: Radical Pair Processes Involving Cryptochrome

    PubMed Central

    Wiltschko, Roswitha; Wiltschko, Wolfgang

    2014-01-01

    Birds can use the geomagnetic field for compass orientation. Behavioral experiments, mostly with migrating passerines, revealed three characteristics of the avian magnetic compass: (1) it works spontaneously only in a narrow functional window around the intensity of the ambient magnetic field, but can adapt to other intensities, (2) it is an “inclination compass”, not based on the polarity of the magnetic field, but the axial course of the field lines, and (3) it requires short-wavelength light from UV to 565 nm Green. The Radical Pair-Model of magnetoreception can explain these properties by proposing spin-chemical processes in photopigments as underlying mechanism. Applying radio frequency fields, a diagnostic tool for radical pair processes, supports an involvement of a radical pair mechanism in avian magnetoreception: added to the geomagnetic field, they disrupted orientation, presumably by interfering with the receptive processes. Cryptochromes have been suggested as receptor molecules. Cry1a is found in the eyes of birds, where it is located at the membranes of the disks in the outer segments of the UV-cones in chickens and robins. Immuno-histochemical studies show that it is activated by the wavelengths of light that allow magnetic compass orientation in birds. PMID:25587420

  8. The role of the sun in the celestial compass of dung beetles.

    PubMed

    Dacke, M; el Jundi, Basil; Smolka, Jochen; Byrne, Marcus; Baird, Emily

    2014-01-01

    Recent research has focused on the different types of compass cues available to ball-rolling beetles for orientation, but little is known about the relative precision of each of these cues and how they interact. In this study, we find that the absolute orientation error of the celestial compass of the day-active dung beetle Scarabaeus lamarcki doubles from 16° at solar elevations below 60° to an error of 29° at solar elevations above 75°. As ball-rolling dung beetles rely solely on celestial compass cues for their orientation, these insects experience a large decrease in orientation precision towards the middle of the day. We also find that in the compass system of dung beetles, the solar cues and the skylight cues are used together and share the control of orientation behaviour. Finally, we demonstrate that the relative influence of the azimuthal position of the sun for straight-line orientation decreases as the sun draws closer to the horizon. In conclusion, ball-rolling dung beetles possess a dynamic celestial compass system in which the orientation precision and the relative influence of the solar compass cues change over the course of the day. PMID:24395963

  9. Quick Reference Guide Create a Compass Account

    E-print Network

    Alpay, S. Pamir

    Quick Reference Guide Create a Compass Account Compass Online Application Compass Page 1 of 1 Draft of: 04/10/2014 Create a Compass Account Path: https first with the creation of your Compass User Name, Password and Confirm Password. Fields with *(asterisk

  10. Compass Financial Stability and Savings Program

    E-print Network

    Fraden, Seth

    Compass Financial Stability and Savings Program Pilot Evaluation: Second Year Report April 2013 Prepared for Compass Working Capital Boston, MA Prepared by Delia Kimbrel, Research Associate Institute, MA #12;Compass Working Capital Compass Working Capital ("Compass") provides incentive-based financial

  11. Class of 2003 Alumni Compass Project: GOAL 120 compasses = $4,800 Every Warnell student will need a compass for field measurements. Not only will a compass

    E-print Network

    Teskey, Robert O.

    Class of 2003 Alumni Compass Project: GOAL 120 compasses = $4,800 Every Warnell student will need a compass for field measurements. Not only will a compass literally help each student find their way, a note would like to give a new student a compass when he or she enters the professional program, we would love

  12. 2007-2009 UC Regents Career Compass...

    E-print Network

    Jacobs, Lucia

    © 2007-2009 UC Regents Career Compass... the SISC initiatives #12;2 What is the Career Compass?What is the Career Compass?What is the Career Compass? Training linked to common job success factors and individual Fars Happened So Far 55+ Career Compass presentations and open sessions provided to over 2200 campus

  13. Spin orientation driven static and dynamic magnetic process in amorphous FeCoBSi thin films

    NASA Astrophysics Data System (ADS)

    Zhou, Peiheng; Luo, Xiaojia; Zhang, Li; Lu, Haipeng; Xie, Jianliang; Deng, Longjiang

    2015-06-01

    The spin orientation dependence of magnetic hysteresis and microwave ferromagnetic resonance data are investigated in FeCoBSi amorphous thin films. Demagnetization effect allows the weak interface-rooted out-of-plane anisotropy to build up local spin orientation domains under the dominant in-plane anisotropy. As a result, two phase magnetization reversal and double-peak ferromagnetic resonance traces with varying damping behavior are observed. Due to the distribution of in-plane and out-of-plane spin orientations, the ferromagnetic resonance bandwidth has been extensively expanded with the full width at half maximum increased from 1.2 GHz to 3.5 GHz.

  14. The British Museum COMPASS

    NSDL National Science Digital Library

    To help visitors find treasures in its vast holdings, the British Museum presents COMPASS, which is based on a database of around 5000 objects selected from the Museum's collections. Simple keyword searches work well in COMPASS, and searches can be limited to a particular index. Who? searches for a particular person, What? searches for particular objects, How? for processes and materials, and Where/When? for geography and date. COMPASS automatically adds the word and between words, just like Google. Object pages include detailed information, written for the average museum go-er, with links into an online glossary, although we were unable to discover why a search on sextant returned astrolabes (consulting another dictionary revealed that the astrolabe was an nautical instrument used prior to the sextant). There are also guided tours, on a huge list of subjects from 100 Views of Mount Fuji to the Wetwang Chariot Burial, with Chinese Jade, several Egypt tours, and over 45 Highlights of the British Museum in between. Another great way to approach COMPASS is to try the Galleries search (found on the search page) where selecting any one of about 35 gallery names displays all the objects in that room.

  15. Future plans at COMPASS

    Microsoft Academic Search

    J. Pretz

    2010-01-01

    After successfully running since several years with polarized muon and hadron beams to study the spin structure of the nucleon and spectroscopy of hadrons, the COMPASS (Common Muon and Proton Apparatus for Structure and Spectroscopy) experiment enters a second phase with a new extended physics program to obtain deeper insight in the partonic structure of matter. These future plans include

  16. Compassion for the Absurd

    Microsoft Academic Search

    Meredith E. McDonough

    2010-01-01

    In Compassion for the Absurd, I hope to find transcendent moments in the ridiculous and mundane scenarios of various lives, some real, some imagined. In focusing on the ordinary, the poems pull the background of life into the foreground and ask the reader to find art in the real rather than the ideal. By focusing on the often ignored marginalia

  17. Prediction of particle orientation in simple upsetting process of NdFeB magnets

    SciTech Connect

    Chang, Chao-Cheng; Hsiao, Po-Jen [Department of Mold and Die Engineering, National Kaohsiung University of Applied Sciences, 415 Chien-Kung Road, Sanmin District, Kaohsiung 80778, Taiwan (China); You, Jr-Shiang; Chen, Yen-Ju; Chang, Can-Xun [Metal Forming Technology Section, Metal Processing R and D Department, Metal Industries Research and Development Centre, 1001 Kaonan Highway, Kaohsiung 81160, Taiwan (China)

    2013-12-16

    The magnetic properties of NdFeB magnets are strongly affected by crystallographic texture which is highly associated with particle orientation. This study proposed a method for predicting the particle orientation in the simple upsetting process of NdFeB magnets. The method is based on finite element simulation with flow net analysis. The magnets in a cylindrical form were compressed by two flat dies in a chamber filled with argon at 750°C. Three forming speeds were taken into account in order to obtain flow stress curves used in simulations. The micrographs of the cross sections of the deformed magnets show that the particle deformation significantly increases with the compression. The phenomenon was also predicted by the proposed method. Both simulated and experimental results show that the inhomogeneity of the texture of the NdFeB magnets can be increased by the simple upsetting process. The predicted particle orientations were in a good agreement with those examined in the deformed magnets. The proposed method for predicting particle orientations can also be used in other forming processes of NdFeB magnets.

  18. Manipulations of polarized skylight calibrate magnetic orientation in a migratory bird

    Microsoft Academic Search

    K. P. Able; M. A. Able

    1995-01-01

    1.Young migratory birds enter the world with two representations of the migratory direction, one coded with respect to the magnetic field, the other with respect to celestial rotation. The preferred magnetic direction of migratory orientation is malleable early in life: it may be calibrated by celestial rotation, observed either in daytime or at night.2.Previous experiments showed that early experience with

  19. Hadron Spectroscopy in COMPASS

    E-print Network

    Boris Grube; for the COMPASS Collaboration

    2013-01-31

    The COmmon Muon and Proton Apparatus for Structure and Spectroscopy (COMPASS) is a multi-purpose fixed-target experiment at the CERN Super Proton Synchrotron (SPS) aimed at studying the structure and spectrum of hadrons. In the naive Constituent Quark Model (CQM) mesons are bound states of quarks and antiquarks. QCD, however, predict the existence of hadrons beyond the CQM with exotic properties interpreted as excited glue (hybrids) or even pure gluonic bound states (glueballs). One main goal of COMPASS is to search for these states. Particularly interesting are so called spin-exotic mesons which have J^{PC} quantum numbers forbidden for ordinary q\\bar{q} states. Its large acceptance, high resolution, and high-rate capability make the COMPASS experiment an excellent device to study the spectrum of light-quark mesons in diffractive and central production reactions up to masses of about 2.5 GeV. COMPASS is able to measure final states with charged as well as neutral particles, so that resonances can be studied in different reactions and decay channels. During 2008 and 2009 COMPASS acquired large data samples using negative and positive secondary hadron beams on lH_2, Ni, and Pb targets. The presented overview of the first results from this data set focuses in particular on the search for spin-exotic mesons in diffractively produced \\pi^-\\pi^+\\pi^-, \\eta\\pi, \\eta'\\pi, and \\pi^-\\pi^+\\pi^-\\pi^+\\pi^- final states and the analysis of central-production of \\pi^+\\pi^- pairs in order to study glueball candidates in the scalar sector.

  20. Drawing Magnetic Fields

    NSDL National Science Digital Library

    VU Bioengineering RET Program,

    Students use a compass and a permanent magnet to trace the magnetic field lines produced by the magnet. By positioning the compass in enough spots around the magnet, the overall magnet field will be evident from the collection of arrows representing the direction of the compass needle. In activities 3 and 4 of this unit, students will use this information to design a way to solve the grand challenge of separating metal for a recycling company.

  1. Autocalibration of an electronic compass in an outdoor augmented reality system

    Microsoft Academic Search

    Bruce Hoff; Ronald Azuma

    2000-01-01

    Accurate registration in an augmented reality system requires accurate trackers. An electronic compass can be a valuable sensor in an outdoor augmented reality system because it provides absolute heading estimates. However, compasses are vulnerable to distortion caused by environmental disturbances to Earth's magnetic field. These disturbances vary with geographic location and are not trivial to model. Static calibration methods exist

  2. Magnetic orientation of the Common Toad: establishing an arena approach for adult anurans

    PubMed Central

    2011-01-01

    Background Magnetic orientation is a taxonomically widespread phenomenon in the animal kingdom, but has been little studied in anuran amphibians. We collected Common Toads (Bufo bufo) during their migration towards their spawning pond and tested them shortly after displacement for possible magnetic orientation in arena experiments. Animals were tested in two different set-ups, in the geomagnetic field and in a reversed magnetic field. To the best of our knowledge, this is the first study testing orientation of adult anurans with a controlled magnetic field of a known strength and alignment. Results After displacement, toads oriented themselves unimodally under the geomagnetic field, following their former migration direction (d-axis). When the magnetic field was reversed, the distribution of bearings changed from a unimodal to a bimodal pattern, but still along the d-axis. The clustering of bearings was only significant after the toads reached the outer circle, 60.5 cm from their starting point. At a virtual inner circle (diameter 39 cm) and at the start of the experiment, orientation of toads did not show any significant pattern. Conclusions The experimental set-up used in our study is suitable to test orientation behaviour of the Common Toad. We speculate that toads had not enough time to relocate their position on an internal map. Hence, they followed their former migration direction. Bimodality in orientation when exposed to the reversed magnetic field could be the result of a cue conflict, between magnetic and possibly celestial cues. For maintaining their migration direction toads use, at least partly, the geomagnetic field as a reference system. PMID:21418651

  3. 46 CFR 130.340 - Compass.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 2014-10-01 2014-10-01 false Compass. 130.340 Section 130.340 Shipping...SYSTEMS Navigational Equipment § 130.340 Compass. Each vessel must be fitted with a compass suitable for the intended service of...

  4. 46 CFR 130.340 - Compass.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 2011-10-01 2011-10-01 false Compass. 130.340 Section 130.340 Shipping...SYSTEMS Navigational Equipment § 130.340 Compass. Each vessel must be fitted with a compass suitable for the intended service of...

  5. 46 CFR 130.340 - Compass.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 2010-10-01 2010-10-01 false Compass. 130.340 Section 130.340 Shipping...SYSTEMS Navigational Equipment § 130.340 Compass. Each vessel must be fitted with a compass suitable for the intended service of...

  6. 46 CFR 130.340 - Compass.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 2012-10-01 2012-10-01 false Compass. 130.340 Section 130.340 Shipping...SYSTEMS Navigational Equipment § 130.340 Compass. Each vessel must be fitted with a compass suitable for the intended service of...

  7. 46 CFR 130.340 - Compass.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 2013-10-01 2013-10-01 false Compass. 130.340 Section 130.340 Shipping...SYSTEMS Navigational Equipment § 130.340 Compass. Each vessel must be fitted with a compass suitable for the intended service of...

  8. In search of the sky compass in the insect brain

    Microsoft Academic Search

    Uwe Homberg

    2004-01-01

    Like many vertebrate species, insects rely on a sun compass for spatial orientation and long- range navigation. In addition to the sun, however, insects can also use the polarization pattern of the sky as a reference for estimating navigational directions. Recent analysis of polarization vision pathways in the brain of orthopteroid insects sheds some light onto brain areas that might

  9. Compassion: Chinese and western perspectives on practical wisdom in management

    Microsoft Academic Search

    Hendrik Opdebeeck; André Habisch

    2011-01-01

    Purpose – The notion of compassion is a cornerstone in Chinese as well as western orientations for business practice. Spiritual and religious traditions, philosophical approaches and historical and present business practices outline this notion in a comparative perspective. This paper seeks to address this issue. Design\\/methodology\\/approach – Interdisciplinary paper, summarizing social science, philosophical and business literature. Findings – With its

  10. Exploring Magnetic Field Lines

    NSDL National Science Digital Library

    NASA

    2012-06-26

    In this activity, learners explore the magnetic field of a bar magnet as an introduction to understanding Earth's magnetic field. First, learners explore and play with magnets and compasses. Then, learners trace the field lines of the magnet using the compass on a large piece of paper. This activity will also demonstrate why prominences are always "loops."

  11. Magnetically induced anisotropic orientation of graphene oxide locked by in situ hydrogelation.

    PubMed

    Wu, Linlin; Ohtani, Masataka; Takata, Masaki; Saeki, Akinori; Seki, Shu; Ishida, Yasuhiro; Aida, Takuzo

    2014-05-27

    A general method to prepare polymer gels containing anisotropically oriented graphene oxide (GO) or reduced graphene oxide (RGO) was developed, by using the magnetically induced orientation of GO. Under a magnetic field, an aqueous dispersion of GO was gelated by in situ cross-linking polymerization of an acryl monomer and a cross-linker. In the resultant hydrogel, the orientation of GO was retained even in the absence of the magnetic field, because the gel network trapped GO via noncovalent interactions and efficiently suppressed the structural relaxation of GO. The locked structure enabled quantitative investigation on the magnetic orientation of GO using 2D small-angle X-ray scattering, which revealed that GO nanosheets orient parallel to the magnetic field with an order parameter of up to 0.80. Systematic studies with varying gelation conditions indicate that the present method can afford a wide range of GO-hybridized anisotropic materials, in terms of GO alignment direction, sample shape, and GO concentration. Also by virtue of the locked structure, the orientation of GO in the hydrogel was well preserved throughout the in situ chemical reduction of GO, yielding an RGO-hybridized anisotropic hydrogel, as well as the conversion of the hydrogel into organo- and ionogels through the replacement of the internal water with solvents. As a preliminary demonstration of the present method for practical application, a polymer-composite film containing RGO oriented vertical to the film surface was prepared, and its anisotropically enhanced electroconductivity along the orientation direction of RGO was confirmed by the flash-photolysis time-resolved microwave conductivity measurement. PMID:24738828

  12. COMPASS: An Ada based scheduler

    NASA Technical Reports Server (NTRS)

    Mcmahon, Mary Beth; Culbert, Chris

    1992-01-01

    COMPASS is a generic scheduling system developed by McDonnell Douglas and funded by the Software Technology Branch of NASA Johnson Space Center. The motivation behind COMPASS is to illustrate scheduling technology and provide a basis from which custom scheduling systems can be built. COMPASS was written in Ada to promote readability and to conform to DOD standards. COMPASS has some unique characteristics that distinguishes it from commercial products. This paper discusses these characteristics and uses them to illustrate some differences between scheduling tools.

  13. An orientation measurement method based on Hall-effect sensors for permanent magnet spherical actuators with 3D magnet array.

    PubMed

    Yan, Liang; Zhu, Bo; Jiao, Zongxia; Chen, Chin-Yin; Chen, I-Ming

    2014-01-01

    An orientation measurement method based on Hall-effect sensors is proposed for permanent magnet (PM) spherical actuators with three-dimensional (3D) magnet array. As there is no contact between the measurement system and the rotor, this method could effectively avoid friction torque and additional inertial moment existing in conventional approaches. Curved surface fitting method based on exponential approximation is proposed to formulate the magnetic field distribution in 3D space. The comparison with conventional modeling method shows that it helps to improve the model accuracy. The Hall-effect sensors are distributed around the rotor with PM poles to detect the flux density at different points, and thus the rotor orientation can be computed from the measured results and analytical models. Experiments have been conducted on the developed research prototype of the spherical actuator to validate the accuracy of the analytical equations relating the rotor orientation and the value of magnetic flux density. The experimental results show that the proposed method can measure the rotor orientation precisely, and the measurement accuracy could be improved by the novel 3D magnet array. The study result could be used for real-time motion control of PM spherical actuators. PMID:25342000

  14. An Orientation Measurement Method Based on Hall-effect Sensors for Permanent Magnet Spherical Actuators with 3D Magnet Array

    NASA Astrophysics Data System (ADS)

    Yan, Liang; Zhu, Bo; Jiao, Zongxia; Chen, Chin-Yin; Chen, I.-Ming

    2014-10-01

    An orientation measurement method based on Hall-effect sensors is proposed for permanent magnet (PM) spherical actuators with three-dimensional (3D) magnet array. As there is no contact between the measurement system and the rotor, this method could effectively avoid friction torque and additional inertial moment existing in conventional approaches. Curved surface fitting method based on exponential approximation is proposed to formulate the magnetic field distribution in 3D space. The comparison with conventional modeling method shows that it helps to improve the model accuracy. The Hall-effect sensors are distributed around the rotor with PM poles to detect the flux density at different points, and thus the rotor orientation can be computed from the measured results and analytical models. Experiments have been conducted on the developed research prototype of the spherical actuator to validate the accuracy of the analytical equations relating the rotor orientation and the value of magnetic flux density. The experimental results show that the proposed method can measure the rotor orientation precisely, and the measurement accuracy could be improved by the novel 3D magnet array. The study result could be used for real-time motion control of PM spherical actuators.

  15. Magnetic properties and dynamic domain behavior in grain-oriented 3% Si-Fe

    SciTech Connect

    Nozawa, Tadao [Kyushu Kyoritsu Univ., Kitakyushi, Fukuska (Japan). Dept. of Electrical Engineering] [Kyushu Kyoritsu Univ., Kitakyushi, Fukuska (Japan). Dept. of Electrical Engineering; Mizogami, Masato; Mogi, Hisasi; Matsuo, Yukio

    1996-03-01

    The magnetic properties of soft magnetic materials are based on dynamic behavior of magnetic domain walls. Many domain structure studies have contributed to the progress of magnetic materials. In this paper, the present state of new development in advanced grain-oriented silicon steel is introduced through the aid of dynamic domain observation of real materials with forsterite film. The basic magnetic phenomena of material, such as the dynamic behavior of surface closure domains, domain wall pinning, and domain structure under rotating magnetization, are explained mainly through the observation of static and dynamic domain wall movements under a high-voltage scanning electron microscope. A few techniques for manufacturing the latest grain-oriented silicon steel, such as improvement in alignment with (110) [001] orientation, increase in the number of mobile domain walls, and relaxation of domain wall pinning, are also described through the observation of dynamic domain patterns. Examples of core losses are given for ideal grain-oriented silicon steel as industrial material, and future developments are predicted.

  16. The COMPASS Project

    NASA Astrophysics Data System (ADS)

    Duley, A. R.; Sullivan, D.; Fladeland, M. M.; Myers, J.; Craig, M.; Enomoto, F.; Van Gilst, D. P.; Johan, S.

    2011-12-01

    The Common Operations and Management Portal for Airborne Science Systems (COMPASS) project is a multi-center collaborative effort to advance and extend the research capabilities of the National Aeronautics and Space Administration's (NASA) Airborne Science Program (ASP). At its most basic, COMPASS provides tools for visualizing the position of aircraft and instrument observations during the course of a mission, and facilitates dissemination, discussion, and analysis and of multiple disparate data sources in order to more efficiently plan and execute airborne science missions. COMPASS targets a number of key objectives. First, deliver a common operating picture for improved shared situational awareness to all participants in NASA's Airborne Science missions. These participants include scientists, engineers, managers, and the general public. Second, encourage more responsive and collaborative measurements between instruments on multiple aircraft, satellites, and on the surface in order to increase the scientific value of these measurements. Fourth, provide flexible entry points for data providers to supply model and advanced analysis products to mission team members. Fifth, provide data consumers with a mechanism to ingest, search and display data products. Finally, embrace an open and transparent platform where common data products, services, and end user components can be shared with the broader scientific community. In pursuit of these objectives, and in concert with requirements solicited by the airborne science research community, the COMPASS project team has delivered a suite of core tools intended to represent the next generation toolset for airborne research. This toolset includes a collection of loosely coupled RESTful web-services, a system to curate, register, and search, commonly used data sources, end-user tools which leverage web socket and other next generation HTML5 technologies to aid real time aircraft position and data visualization, and an extensible a framework to rapidly accommodate mission specific requirements and mission tools.

  17. Transversity Measurements at COMPASS

    E-print Network

    COMPASS Collaboration; C. Schill

    2007-09-28

    The measurement of transverse spin effects in semi-inclusive deep-inelastic scattering is an important part of the COMPASS physics program. From the analysis of the 2002-2004 data, new results for the transverse target spin asymmetry of z-ordered identified pion and kaon pairs are presented. In addition, a first result for the transverse target spin asymmetry of exclusively produced rho^0 mesons on the deuteron is shown.

  18. Reconstruction of Cardiac Ventricular Geometry and Fiber Orientation Using Magnetic Resonance Imaging

    Microsoft Academic Search

    D. F. Scollan; A. Holmes; J. Zhang; R. L. Winslow

    2000-01-01

    An imaging method for the rapid reconstruction of fiber orientation throughout the cardiac ventricles is described. In this method, gradient-recalled acquisition in the steady-state (GRASS) imaging is used to measure ventricular geometry in formaldehyde-fixed hearts at high spatial resolution. Diffusion-tensor magnetic resonance imaging (DTMRI) is then used to estimate fiber orientation as the principle eigenvector of the diffusion tensor measured

  19. Estimating Three-Dimensional Orientation of Human Body Parts by Inertial/Magnetic Sensing

    PubMed Central

    Sabatini, Angelo Maria

    2011-01-01

    User-worn sensing units composed of inertial and magnetic sensors are becoming increasingly popular in various domains, including biomedical engineering, robotics, virtual reality, where they can also be applied for real-time tracking of the orientation of human body parts in the three-dimensional (3D) space. Although they are a promising choice as wearable sensors under many respects, the inertial and magnetic sensors currently in use offer measuring performance that are critical in order to achieve and maintain accurate 3D-orientation estimates, anytime and anywhere. This paper reviews the main sensor fusion and filtering techniques proposed for accurate inertial/magnetic orientation tracking of human body parts; it also gives useful recipes for their actual implementation. PMID:22319365

  20. Estimating three-dimensional orientation of human body parts by inertial/magnetic sensing.

    PubMed

    Sabatini, Angelo Maria

    2011-01-01

    User-worn sensing units composed of inertial and magnetic sensors are becoming increasingly popular in various domains, including biomedical engineering, robotics, virtual reality, where they can also be applied for real-time tracking of the orientation of human body parts in the three-dimensional (3D) space. Although they are a promising choice as wearable sensors under many respects, the inertial and magnetic sensors currently in use offer measuring performance that are critical in order to achieve and maintain accurate 3D-orientation estimates, anytime and anywhere. This paper reviews the main sensor fusion and filtering techniques proposed for accurate inertial/magnetic orientation tracking of human body parts; it also gives useful recipes for their actual implementation. PMID:22319365

  1. Orientation in the wandering albatross: interfering with magnetic perception does not affect orientation performance

    PubMed Central

    Bonadonna, F; Bajzak, C; Benhamou, S; Igloi, K; Jouventin, P; Lipp, H.P; Dell'Omo, G

    2005-01-01

    After making foraging flights of several thousands of kilometres, wandering albatrosses (Diomedea exulans) are able to pinpoint a specific remote island where their nests are located. This impressive navigation ability is highly precise but its nature is mysterious. Here we examined whether albatrosses rely on the perception of the Earth's magnetic field to accomplish this task. We disturbed the perception of the magnetic field using mobile magnets glued to the head of nine albatrosses and compared their performances with those of 11 control birds. We then used satellite telemetry to monitor their behaviour. We found that the ability of birds to home to specific nest sites was unimpaired by this manipulation. In particular, experimental and control birds did not show significant differences with respect to either foraging trip duration, or length, or with respect to homing straightness index. Our data suggest that wandering albatrosses do not require magnetic cues to navigate back to their nesting sites. PMID:15799944

  2. Optical orientation of Mn2+ ions in GaAs in weak longitudinal magnetic fields.

    PubMed

    Akimov, I A; Dzhioev, R I; Korenev, V L; Kusrayev, Yu G; Sapega, V F; Yakovlev, D R; Bayer, M

    2011-04-01

    We report on optical orientation of Mn2+ ions in bulk GaAs subject to weak longitudinal magnetic fields (B?100??mT). A manganese spin polarization of 25% is directly evaluated by using spin-flip Raman scattering. The dynamical Mn2+ polarization occurs due to the s-d exchange interaction with optically oriented conduction band electrons. Time-resolved photoluminescence reveals a nontrivial electron spin dynamics, where the oriented Mn2+ ions tend to stabilize the electron spins. PMID:21561222

  3. Spin orientation, structure, morphology, and magnetic properties of hematite nanoparticles

    NASA Astrophysics Data System (ADS)

    Xu, S.; Habib, A. H.; Gee, S. H.; Hong, Y. K.; McHenry, M. E.

    2015-05-01

    Monodisperse hematite (?-Fe2O3) nanoparticles were synthesized by forced hydrolysis of acidic Fe3+ solution. Rietveld analysis was applied to the X-ray powder diffraction data to refine the lattice constants and atomic positions. The lattice constants for a hexagonal unit cell were determined to be a ˜ 0.50327 and c ˜ 1.37521 nm. High resolution transmission electron microscopy was employed to study the morphology of the particles. Atomic scale micrographs and diffraction patterns from several zone axes were obtained. These reveal the high degree of crystallinity of the particles. A series of observations made on the particles by tilting them through a range of ±45° revealed the particles to be micaceous with stacking of platelets with well defined crystallographic orientations. The Morin transition in these nanoparticles was found to occur at 210 K, which is lower temperature than 263 K of bulk hematite. It was ascertained from the previous Mössbauer studies that the spin orientation for nano-sized hematite particle flips from 90° to 28° with respect to the c-axis of the hexagonal structure during the Morin transition, which is in contrast to that observed in bulk hematite where spin orientation flips from 90° to 0°.

  4. Effect of orientation of the solar wind magnetic clouds on the seasonal variation of geomagnetic activity

    NASA Astrophysics Data System (ADS)

    Barkhatov, N. A.; Revunova, E. A.; Vinogradov, A. B.

    2014-07-01

    An analysis is made of the causes of seasonal dependence of geomagnetic activity, taking into account orientation of large-scale plasma structures (of the magnetic cloud type) of the solar wind. The contribution of magnetic clouds of different orientation in the periods of equinoxes and solstices is demonstrated. It is established that in equinox periods the geomagnetic activity increases due to ejections with small angles of inclination of their axis to the ecliptic plane, most frequently detected in near-Earth space. In solstice periods, such clouds are not geoeffective structures because of a decreased magnitude of projection of the magnetic field of cloud axis onto the Earth's magnetic dipole during such intervals. This effect reveals itself in a reduced level of geomagnetic activity in summer and winter.

  5. Acoustic properties of hematite near the orientation phase transitions in magnetic fields and under pressure

    NASA Astrophysics Data System (ADS)

    Migachev, S. A.; Bogdanova, Kh. G.; Kurkin, M. I.

    2015-01-01

    This paper reports on the results of the experimental investigation of the quasi-phonon (quasi-sound) branch of magnetoelastic waves in hematite (?-Fe2O3) in the easy-plane state near the orientation phase transitions in magnetic fields H and under uniaxial pressure P. It has been found that, in an applied external magnetic field H > 1.0 kOe and at a uniaxial pressure P > 40 MPa, the amplitude of the transmitted quasi-sound abruptly increases. The minima of quasi-sound velocities observed at the orientation phase transition points in the magnetic field H are consistent with the predictions of the existing theory of magnetoelastic waves, but their width significantly exceeds the theoretical values. The minima of quasi-sound velocities at a uniaxial pressure P are observed only in magnetic fields H < 3 kOe and, at H > 3 kOe, turn into extended plateaus.

  6. Quantitative vertebral compression fracture evaluation using a height compass

    NASA Astrophysics Data System (ADS)

    Yao, Jianhua; Burns, Joseph E.; Wiese, Tatjana; Summers, Ronald M.

    2012-03-01

    Vertebral compression fractures can be caused by even minor trauma in patients with pathological conditions such as osteoporosis, varying greatly in vertebral body location and compression geometry. The location and morphology of the compression injury can guide decision making for treatment modality (vertebroplasty versus surgical fixation), and can be important for pre-surgical planning. We propose a height compass to evaluate the axial plane spatial distribution of compression injury (anterior, posterior, lateral, and central), and distinguish it from physiologic height variations of normal vertebrae. The method includes four steps: spine segmentation and partition, endplate detection, height compass computation and compression fracture evaluation. A height compass is computed for each vertebra, where the vertebral body is partitioned in the axial plane into 17 cells oriented about concentric rings. In the compass structure, a crown-like geometry is produced by three concentric rings which are divided into 8 equal length arcs by rays which are subtended by 8 common central angles. The radius of each ring increases multiplicatively, with resultant structure of a central node and two concentric surrounding bands of cells, each divided into octants. The height value for each octant is calculated and plotted against octants in neighboring vertebrae. The height compass shows intuitive display of the height distribution and can be used to easily identify the fracture regions. Our technique was evaluated on 8 thoraco-abdominal CT scans of patients with reported compression fractures and showed statistically significant differences in height value at the sites of the fractures.

  7. Compass Financial Stability and Savings Program

    E-print Network

    Fraden, Seth

    Compass Financial Stability and Savings Program Pilot Evaluation: Final Report 1 April 2014 Prepared for Compass Working Capital Boston, MA Prepared by Delia Kimbrel, Research Associate Sandra Venner Brandeis University, Waltham, MA #12;2 Compass Working Capital ("Compass") provides incentive

  8. COMPASS Model Review Draft February 29, 2008

    E-print Network

    Washington at Seattle, University of

    COMPASS Model Review Draft February 29, 2008 Page i Comprehensive Passage (COMPASS) Model ­ version 1.1 Review DRAFT February 2008 #12;COMPASS Model Review Draft February 29, 2008 Page ii Table-Bonneville survival 8c. Prospective hydrological modeling Appendix 9. Sensitivity analyses #12;COMPASS Model Review

  9. Synthesis and orientation of barium hexaferrite ceramics by magnetic alignment

    NASA Astrophysics Data System (ADS)

    Autissier, Denis

    1990-01-01

    Particles of Ba 2Mn xZn 2- xFe 12O 22 with planar structure were prepared by chemical precipitation. They were processed by sleep casting in presence of a magnetic field. The degree of alignment was improved by a special sintering treatment. By this procedure an alignment as high as 99.9% is obtained.

  10. Local distribution on magnetic properties in grain-oriented silicon steel sheet

    NASA Astrophysics Data System (ADS)

    Enokizono, Masato; Tanabe, Ikuo; Kubota, Takeshi

    1998-06-01

    Grain-oriented silicon steel is the most important soft magnetic material used as core material of large transformers, large rotating machines, and pole transformers. Total loss of grain-oriented silicon steel tends to become lower with an increasing degree of texture. However, the material which has a higher degree of texture ordinarily contains larger grains, and the materials which have larger grains show higher total loss due to increased eddy current loss. As the gauge is reduced, the rate of decrease in total loss becomes lower for the thinner gauge due to increased hysteresis loss. However, the investigation of local magnetic properties due to grain situation in this sheet was not discussed from the viewpoint of the distribution of localized magnetic properties, for example, iron loss, hysteresis loop, behavior H vector (magnetic field strength) and B vector (Magnetic flux density). This paper describes the distribution of magnetic properties in high oriented silicon steel sheet, which are loss, hysteresis loop, and locus of field strength.

  11. Transport driven plasma flows in the scrape-off layer of ADITYA Tokamak in different orientations of magnetic field

    SciTech Connect

    Sangwan, Deepak; Jha, Ratneshwar; Brotankova, Jana; Gopalkrishna, M. V. [Institute for Plasma Research, Gandhinagar 382428 (India)

    2014-06-15

    Parallel plasma flows in the scrape-off layer of ADITYA tokamak are measured in two orientations of total magnetic field. In each orientation, experiments are carried out by reversing the direction of the toroidal magnetic field and the plasma current. The transport-driven component is determined by averaging flow Mach numbers, measured in two directions of the toroidal magnetic field and the plasma current for the same orientation. It is observed that there is a significant transport-driven component in the measured flow and the component depends on the field orientation.

  12. Magnetic properties and domain structure in grain-oriented 3% Si-Fe

    Microsoft Academic Search

    J. W. SHILLING

    1974-01-01

    Magnetic domain observations have been used to clarify the relationship between metallurgical structure and the core loss, permeability, and magnetostriction of grain-oriented 3% Si-Fe. Both the prediction of domain structures based on anisotropy, magnetostatics, stress, etc., and the various methods of making domain observations are reviewed. Both static and dynamic domain structures are shown and used to illustrate the relationships

  13. The effect of precipitate size on magnetic domain behavior in grain-oriented electrical steels

    NASA Astrophysics Data System (ADS)

    Turner, Steven; Moses, Anthony; Hall, Jeremy; Jenkins, Keith

    2010-05-01

    Precipitates in the form of grain growth inhibitors play an essential role in the production of grain-oriented electrical steels, as they promote the development of Goss texture during secondary recrystallization. However, the presence of precipitates in the final material can have a detrimental effect on loss and permeability, as they impede domain wall motion during the magnetization process. In previous work [K. Jenkins and M. Lindenmo, J. Magn. Magn. Mater. 320, 2423 (2008)], a conventional grain-oriented electrical steel was presented that contained very fine precipitates, which did not damage the bulk magnetic properties. In this article the influence of precipitate size is investigated by comparing local Barkhausen noise measurements and electron backscatter diffraction analysis for a number of grain-oriented electrical steels, which are metallurgically similar except for the size and abundance of precipitates.

  14. Compass & Straight Edge Constructions

    NSDL National Science Digital Library

    Mrs. Silotti

    2007-06-12

    Use compass & straight edge to do basic constructions. Follow the directions to construct a segment bisector. construct midpoint or segment bisector Now, follow the directions to construct a perpendicular line through a point on a line. Construct a perpendicular line through a point on a line Another perpendicular line to construct is one through a point not on a line. Construct a perpendicular line through a point not on the line Now we\\'ve constructed perpendicular lines, let\\'s construct a parallel line. ...

  15. Baryon Spectroscopy at COMPASS

    E-print Network

    Alexander Austregesilo; for the the COMPASS collaboration

    2011-09-01

    At the COMPASS experiment, diffractive dissociation of the beam proton is one of the dominant processes for the 190GeV/c positive hadron beam impinging on a liquid hydrogen target. The status of the analysis of the reactions pp -> p_f pi^+ pi^- p_s and pp -> p_f K^+ K^- p_s is presented, where dominant features of the light-baryon spectrum become clearly visible. Furthermore, partial-wave analysis techniques to disentangle these spectra are discussed.

  16. Crystalline Orientation and Perpendicular Magnetic Anisotropy of Iron Oxide Thin Films Deposited by Target Facing Type Sputtering

    Microsoft Academic Search

    Y. Hoshi; M. Naoe

    1987-01-01

    Opposed-target sputtering is employed to produce Fe3O4 single-phase films with (111) orientation on glass substrates and ZnO-coated silicon wafers. The magnetostriction values of these films were larger than those of randomly oriented films, which caused the film to have a large perpendicular magnetic anisotropy. Low pressure during sputtering improved the (111) orientation, but also increased the perpendicular magnetic anisotropy. Attempts

  17. Two-axis piezo rotator for orienting samples in magnetic fields at millikelvin temperatures

    NASA Astrophysics Data System (ADS)

    Fox, Eli; Bestwick, Andrew; Sharpe, Aaron; Goldhaber-Gordon, David; Lindenberg, Tobias; Pickert, Thomas; Otto, Florian

    2015-03-01

    The ability to apply large magnetic fields in any arbitrarily-chosen direction with angular precision at the millikelvin temperature scale enables a range of condensed matter experiments. Here we report on the integration of a custom attocube 2-axis rotary stepper positioner, with the ability to rotate a sample over the full 3D sphere with milli-degree precision, into a cryogen-free, top-loading dilution refrigerator with a single-axis 14 T magnet. We discuss technical details of the rotator unit, refrigerator probe wiring and construction, and proof-of-principle measurements demonstrating precise closed loop control of magnetic field orientation.

  18. Virtual migration in tethered flying monarch butterflies reveals their orientation mechanisms.

    PubMed

    Mouritsen, Henrik; Frost, Barrie J

    2002-07-23

    A newly developed flight simulator allows monarch butterflies to fly actively for up to several hours in any horizontal direction while their fall migratory flight direction can be continuously recorded. From these data, long segments of virtual flight paths of tethered, flying, migratory monarch butterflies were reconstructed, and by advancing or retarding the butterflies' circadian clocks, we have shown that they possess a time-compensated sun compass. Control monarchs on local time fly approximately southwest, those 6-h time-advanced fly southeast, and 6-h time-delayed butterflies fly in northwesterly directions. Moreover, butterflies flown in the same apparatus under simulated overcast in natural magnetic fields were randomly oriented and did not change direction when magnetic fields were rotated. Therefore, these experiments do not provide any evidence that monarch butterflies use a magnetic compass during migration. PMID:12107283

  19. Virtual migration in tethered flying monarch butterflies reveals their orientation mechanisms

    PubMed Central

    Mouritsen, Henrik; Frost, Barrie J.

    2002-01-01

    A newly developed flight simulator allows monarch butterflies to fly actively for up to several hours in any horizontal direction while their fall migratory flight direction can be continuously recorded. From these data, long segments of virtual flight paths of tethered, flying, migratory monarch butterflies were reconstructed, and by advancing or retarding the butterflies' circadian clocks, we have shown that they possess a time-compensated sun compass. Control monarchs on local time fly approximately southwest, those 6-h time-advanced fly southeast, and 6-h time-delayed butterflies fly in northwesterly directions. Moreover, butterflies flown in the same apparatus under simulated overcast in natural magnetic fields were randomly oriented and did not change direction when magnetic fields were rotated. Therefore, these experiments do not provide any evidence that monarch butterflies use a magnetic compass during migration. PMID:12107283

  20. Quantum limit for avian magnetoreception: How sensitive can a chemical compass be?

    E-print Network

    Jianming Cai; Filippo Caruso; Martin B. Plenio

    2011-10-31

    The chemical compass model, based on radical pair reactions, is a fascinating idea to explain avian magnetoreception. At present, questions concerning the key ingredients responsible for the high sensitivity of a chemical compass and the possible role of quantum coherence and decoherence remain unsolved. Here, we investigate the optimized hyperfine coupling for a chemical compass in order to achieve the best magnetic field sensitivity. We show that its magnetic sensitivity limit can be further extended by simple quantum control and may benefit from additional decoherence. With this, we clearly demonstrate how quantum coherence can be exploited in the functioning of a chemical compass. The present results also provide new routes towards the design of a biomimetic weak magnetic field sensor.

  1. Sunset and the orientation of a nocturnal migrant bird

    Microsoft Academic Search

    Frank R. Moore

    1978-01-01

    THE information required for compass orientation among migratory birds is potentially available in the form of numerous environmental stimuli or cues1. Most passerine migrants complete their annual migrations at night, and their orientation is though to depend on a star compass or one based on geomagnetic stimuli1. The pioneering work of Kramer2 suggested that the setting sun may play a

  2. Coordinating compass-based and nest-based flight directions during bumblebee learning and return flights.

    PubMed

    Collett, Thomas S; de Ibarra, Natalie Hempel; Riabinina, Olena; Philippides, Andrew

    2013-03-15

    Bumblebees tend to face their nest over a limited range of compass directions when learning the nest's location on departure and finding it on their approach after foraging. They thus obtain similar views of the nest and its surroundings on their learning and return flights. How do bees coordinate their flights relative to nest-based and compass-based reference frames to get such similar views? We show, first, that learning and return flights contain straight segments that are directed along particular compass bearings, which are independent of the orientation of a bee's body. Bees are thus free within limits to adjust their viewing direction relative to the nest, without disturbing flight direction. Second, we examine the coordination of nest-based and compass-based control during likely information gathering segments of these flights: loops during learning flights and zigzags on return flights. We find that bees tend to start a loop or zigzag when flying within a restricted range of compass directions and to fly towards the nest and face it after a fixed change in compass direction, without continuous interactions between their nest-based and compass-based directions of flight. A preferred trajectory of compass-based flight over the course of a motif, combined with the tendency of the bees to keep their body oriented towards the nest automatically narrows the range of compass directions over which bees view the nest. Additionally, the absence of interactions between the two reference frames allows loops and zigzags to have a stereotyped form that can generate informative visual feedback. PMID:23447669

  3. Orienteering and Rogaining Server

    NSDL National Science Digital Library

    The Orienteering and Rogaining WWW Server is now on-line with information on clubs and federations from around the world, including schedules, results, maps and people to contact for more information. Orienteering is the use of a highly detailed map and a compass to find one's way through unknown surroundings and, if done competitively, in the least possible time. Rogaining is the sport of long distance cross-country navigation in which teams of two to five members, on foot using map and compass, visit as many checkpoints as possible in up to twenty-four hours.

  4. Effect of modified magnetic field on the ocean migration of maturing chum salmon, Oncorhynchus keta

    Microsoft Academic Search

    A. Yano; M. Ogura; A. Sato; Y. Sakaki; Y. Shimizu; N. Baba; K. Nagasawa

    1997-01-01

    To investigate the role of magnetic compass orientation in oceanic migrating chum salmon, Oncorhynchus keta, an ultrasonic telemetry study was carried out in the western North Pacific off the coast of Kushiro, Hokkaido. Four salmon\\u000a were fitted with a tag which generated an artificial magnetic field and modified the geomagnetic field around the head of\\u000a the fish. Initially, the free-ranging

  5. Electronic compass and vertical-angle measurement sensor: applications and benefits to the soldier system

    Microsoft Academic Search

    Barry A. Roberts; Angela Johnson; Ronald A. Belt; Bill Platt

    1998-01-01

    The purpose of an electronic Compass and Vertical Angle Measurement (CVAM) sensor is to measure the attitude\\/orientation (i.e., azimuth, elevation, and cant; in terms of true North and local vertical) of the object to which it is attached. This measurement of orientation enables the addition of valuable functionality to the soldier system. Currently the Force XXI Land Warrior (FXXI LW)

  6. Sensitive chemical compass assisted by quantum criticality

    NASA Astrophysics Data System (ADS)

    Cai, C. Y.; Ai, Qing; Quan, H. T.; Sun, C. P.

    2012-02-01

    A radical-pair-based chemical reaction might be used by birds for navigation via the geomagnetic direction. The inherent physical mechanism is that the quantum coherent transition from a singlet state to triplet states of the radical pair could respond to a weak magnetic field and be sensitive to the direction of such a field; this then results in different photopigments to be sensed by the avian eyes. Here, we propose a quantum bionic setup, inspired by the avian compass, as an ultrasensitive probe of a weak magnetic field based on the quantum phase transition of the environments of the two electrons in the radical pair. We prove that the yield of the chemical products via recombination from the singlet state is determined by the Loschmidt echo of the environments with interacting nuclear spins. Thus quantum criticality of environments could enhance the sensitivity of detection of weak magnetic fields.

  7. Magnetic-field-orientation dependent magnetization reversal and spin waves in elongated permalloy nanorings

    E-print Network

    Adeyeye, Adekunle

    ) Positive exchange bias and upward magnetic relaxation in a Fe-film/CoO-nanoparticle hybrid system Appl magnetite nano-hollow spheres J. Appl. Phys. 112, 064318 (2012) Magnetization reversal in multisegmented

  8. Transversity signals at COMPASS

    E-print Network

    By COMPASS Collaboration

    2007-12-19

    COMPASS is a fixed target experiment at the CERN SPS, with a rich physics program focused on nucleon spin structure and on hadron spectroscopy. One of the main goals of the spin program is the measurement of the transverse spin distribution function $\\Delta_T q(x)$ in semi-inclusive DIS off transversely polarized nucleons. For this purpose approximately 20% of the running time in the years 2002 to 2004 with the longitudinally polarized muon beam of 160 GeV and with $^6$LiD polarized target was used to collect data with the target polarized transversely with respect to the beam direction. The 2002 data have been already analysed and published. We present here the preliminary results from the full statistics for the Collins and Sivers single hadron asymmetries and for the transverse spin asymmetry in hadron pair production.

  9. Hadron Spectroscopy with COMPASS

    E-print Network

    Boris Grube; for the COMPASS Collaboration

    2011-08-29

    COMPASS is a multi-purpose fixed-target experiment at the CERN Super Proton Synchrotron aimed at studying the structure and spectrum of hadrons. One primary goal is the search for new hadronic states, in particular spin-exotic mesons and glueballs. We present recent results of partial-wave analyses of (3\\pi)^- and \\pi^-\\eta' final states based on a large data set of diffractive dissociation of a 190 GeV/c \\pi^- beam on a proton target in the squared four-momentum-transfer range 0.1 < t' < 1 (GeV/c)^2. We also show first results from a partial-wave analysis of diffractive dissociation of K^- into K^-\\pi^+\\pi^- final states are presented.

  10. Transversity Physics at Compass

    E-print Network

    F. Bradamante

    2006-02-06

    Transverse spin physics is an important part of the scientific programme of the COMPASS experiment at CERN, which started taking data in 2002, scattering 160 GeV/c muon beam on a polarized $^6$LiD target. The analysis of the data taken with the target polarized orthogonally to the muon beam direction has allowed to measure for the first time the Collins and Sivers asymmetries of the deuteron. Both for the positive and the negative hadrons produced in semi-inclusive DIS the measured asymmetries are small and, within errors, compatible with zero: results on part of the accumulated statistics have already been published. Two-hadron asymmetries and $\\Lambda$ polarization transfered from the struck quark are also being investigated, and preliminary results on the data collected in the years 2002 and 2003 are given.

  11. Distinctive uniaxial magnetic anisotropy and positive magnetoresistance in (110)-oriented Fe3O4 films

    NASA Astrophysics Data System (ADS)

    Dho, Joonghoe; Kim, Byeong-geon; Ki, Sanghoon

    2015-04-01

    Magnetite (Fe3O4) films were synthesized on (110)-oriented MgO, MgAl2O4, and SrTiO3 substrates for comparative studies of the substrates' effects on magnetic and magnetoresistance properties of the films. For the [-110] direction, the hysteresis loops of the Fe3O4 film on MgAl2O4 exhibited a good squareness with the largest coercivity of ˜1090 Oe, and the ratio of remanent magnetization to saturation magnetization was ˜0.995. For the [001] direction, positive magnetoresistance in weak magnetic fields was most distinct for the (110) SrTiO3 substrate with the largest lattice mismatch. Positive magnetoresistance in the (110) Fe3O4 films was presumably affected by imperfect atomic arrangements at anti-phase boundaries.

  12. Magnetic manipulation of actin orientation, polymerization, and gliding on myosin using superparamagnetic iron oxide particles.

    PubMed

    Chen, Yun; Guzik, Stephanie; Sumner, James P; Moreland, John; Koretsky, Alan P

    2011-02-11

    The actin cytoskeleton controls cell shape, motility, as well as intracellular molecular trafficking. The ability to remotely manipulate actin is therefore highly desirable as a tool to probe and manipulate biological processes at the molecular level. We demonstrate actin manipulation by labeling actin filaments with superparamagnetic iron oxide particles (IOPs) and applying a uniform magnetic field to affect actin orientation, polymerization and gliding on myosin. We show for the first time magnetic manipulation of magnetizable actin filaments at the molecular level while gliding on a bed of myosin molecules and during polymerization. A model for the magnetic alignment and guiding mechanism is proposed based on the torque from the induced molecular anisotropy due to interactions between neighboring IOPs distributed along magnetically labeled actin molecules. PMID:21212476

  13. Orientation Measurement Based on Magnetic Inductance by the Extended Distributed Multi-Pole Model

    PubMed Central

    Wu, Fang; Moon, Seung Ki; Son, Hungsun

    2014-01-01

    This paper presents a novel method to calculate magnetic inductance with a fast-computing magnetic field model referred to as the extended distributed multi-pole (eDMP) model. The concept of mutual inductance has been widely applied for position/orientation tracking systems and applications, yet it is still challenging due to the high demands in robust modeling and efficient computation in real-time applications. Recently, numerical methods have been utilized in design and analysis of magnetic fields, but this often requires heavy computation and its accuracy relies on geometric modeling and meshing that limit its usage. On the other hand, an analytical method provides simple and fast-computing solutions but is also flawed due to its difficulties in handling realistic and complex geometries such as complicated designs and boundary conditions, etc. In this paper, the extended distributed multi-pole model (eDMP) is developed to characterize a time-varying magnetic field based on an existing DMP model analyzing static magnetic fields. The method has been further exploited to compute the mutual inductance between coils at arbitrary locations and orientations. Simulation and experimental results of various configurations of the coils are presented. Comparison with the previously published data shows not only good performance in accuracy, but also effectiveness in computation. PMID:24977389

  14. Local electrical control of magnetic order and orientation by ferroelastic domain arrangements just above room temperature

    PubMed Central

    Phillips, L. C.; Cherifi, R. O.; Ivanovskaya, V.; Zobelli, A.; Infante, I. C.; Jacquet, E.; Guiblin, N.; Ünal, A. A.; Kronast, F.; Dkhil, B.; Barthélémy, A.; Bibes, M.; Valencia, S.

    2015-01-01

    Ferroic materials (ferromagnetic, ferroelectric, ferroelastic) usually divide into domains with different orientations of their order parameter. Coupling between different ferroic systems creates new functionalities, for instance the electrical control of macroscopic magnetic properties including magnetization and coercive field. Here we show that ferroelastic domains can be used to control both magnetic order and magnetization direction at the nanoscale with a voltage. We use element-specific X-ray imaging to map the magnetic domains as a function of temperature and voltage in epitaxial FeRh on ferroelastic BaTiO3. Exploiting the nanoscale phase-separation of FeRh, we locally interconvert between ferromagnetic and antiferromagnetic states with a small electric field just above room temperature. Imaging and ab initio calculations show the antiferromagnetic phase of FeRh is favoured by compressive strain on c-oriented BaTiO3 domains, and the resultant magnetoelectric coupling is larger and more reversible than previously reported from macroscopic measurements. Our results emphasize the importance of nanoscale ferroic domain structure and the promise of first-order transition materials to achieve enhanced coupling in artificial multiferroics. PMID:25969926

  15. Effects of variation in solar conditions and crustal sources' orientation on the Martian magnetic field topology

    NASA Astrophysics Data System (ADS)

    Ulusen, D.; Luhmann, J. G.; Ma, Y.; Brain, D. A.

    2013-12-01

    Strong crustal magnetic sources on the surface of Mars directly interact with the solar magnetic field and plasma, resulting a very dynamic environment near the planet. Effects of the orientation of these remnant magnetic sources with respect to the sun and variation of the solar conditions on the Martian plasma interaction have been investigated in a previous paper. In this previous study, magnetic topology maps obtained from ~7 years of Mars Global Surveyor (MGS) directional electron observations (obtained by Dave Brain) were compared with the topology maps obtained from a set of BATS-R-US MHD simulations for Mars. One conclusion from this study was that although the MHD model is consistent with the data and provides insight about the global magnetic field topology variation with changing crustal field orientation and solar parameters, detailed investigation of local effects is difficult due to MGS orbital bias. Moreover, proper comparison of the observations with the model requires more careful data selection rather than using 7 years time averages. In this paper, we readdress the study to tackle the problems of our previous work by performing more detailed data analysis and present the results of the updated model-data comparison.

  16. Magnetic Moment of Sm145 and Attenuation Following the Decay of Oriented Sm145

    Microsoft Academic Search

    Morton Kaplan; J. Blok; D. A. Shirley

    1969-01-01

    Samarium-145 nuclei were oriented at low temperatures in neodymium ethylsulfate (NES) and cerium magnesium nitrate (CMN) lattices. From the temperature-dependent angular distribution of the 61-keV gamma ray in Pm145, a magnetic moment mu=0.92+\\/-0.06muN was deduced for the ground state of Sm145. The ratio of attenuation coefficients in the 61-keV state of Pm145 in the two lattices was found to be

  17. Magnetic-field-induced alignment-to-orientation conversion in sodium

    Microsoft Academic Search

    X. L. Han; G. W. Schinn

    1991-01-01

    We report a detailed investigation of excited-state alignment-to-orientation conversion in the presence of an external magnetic field. This counterintuitive phenomenon occurs under intermediate-coupling conditions. A weak, linearly polarized, cw laser beam was used to excite and align the Na 3P3\\/2 state in an atomic beam along the z direction. The degree of circular polarization of the resulting fluorescence was detected

  18. Imperfect oriented attachment: Direct activation of high-temperature ferromagnetism in diluted magnetic semiconductor nanocrystals

    Microsoft Academic Search

    Xuefeng Wang; J. B. Xu; Ning Ke; Jiaguo Yu; Juan Wang; Quan Li; H. C. Ong; R. Zhang

    2006-01-01

    We report on a simple nonequilibrium solvothermal synthesis of Co-doped ZnO diluted magnetic semiconductor (DMS) nanocrystals. The crystal growth mechanism of imperfect three-dimensionally oriented attachment was revealed by the high-resolution transmission electron microscopy. The shallow donorlike defects as the legacy of aggregation-based growth were responsible for the observed high-temperature ferromagnetism (FM), further verifying the recent proposal. The solvothermal-treated strategy may

  19. Polarised Drell-Yan physics at COMPASS Celso Franco, on behalf of the COMPASS collaboration

    E-print Network

    Heller, Barbara

    Polarised Drell-Yan physics at COMPASS Celso Franco, on behalf of the COMPASS collaboration LIP, Av. Elias Garcia 14 - 1 1000-149 Lisboa The COMPASS experiment at CERN is one of the leading experiments PDFs without involving fragmentation functions (FFs). COMPASS aims to per- form the first ever

  20. Electric and Magnetic Field Detection in Elasmobranch Fishes

    NASA Astrophysics Data System (ADS)

    Kalmijn, Ad. J.

    1982-11-01

    Sharks, skates, and rays receive electrical information about the positions of their prey, the drift of ocean currents, and their magnetic compass headings. At sea, dogfish and blue sharks were observed to execute apparent feeding responses to dipole electric fields designed to mimic prey. In training experiments, stingrays showed the ability to orient relative to uniform electric fields similar to those produced by ocean currents. Voltage gradients of only 5 nanovolts per centimeter would elicit either behavior.

  1. Quantum control and entanglement in a chemical compass

    E-print Network

    Jianming Cai; Gian Giacomo Guerreschi; Hans J. Briegel

    2010-05-10

    The radical pair mechanism is one of the two main hypotheses to explain the navigability of animals in weak magnetic fields, enabling e.g. birds to see the Earth's magnetic field. It also plays an essential role in the field of spin chemistry. Here, we show how quantum control can be used to either enhance or reduce the performance of such a chemical compass, providing a new route to further study the radical pair mechanism and its applications. We study the role of quantum entanglement in this mechanism, and demonstrate intriguing connections between radical-pair entanglement and the magnetic field sensitivity of the compass. Beyond their immediate application to the radical pair mechanism, these results also demonstrate how state-of-the-art quantum technologies could potentially be used to probe and control biological functions.

  2. Magnetically Actuated Propellant Orientation, Controlling Fluids in a Low-Gravity Environment

    NASA Technical Reports Server (NTRS)

    Martin, James J.; Holt, James B.

    2000-01-01

    Cryogenic fluid management (CFM) is a technology area common to virtually every space transportation propulsion concept envisioned. Storage, supply, transfer and handling of sub-critical cryogenic fluids are basic capabilities that have long been needed by multiple programs and the need is expected to continue in the future. The use of magnetic fields provides another method, which could replace or augment current/traditional approaches, potentially simplifying vehicle operational constraints. The magnetically actuated propellant orientation (MAPO) program effort focused on the use of magnetic fields to control fluid motion as it relates to positioning (i.e. orientation and acquisition) of a paramagnetic substance such as LO2. Current CFM state- of-the-art systems used to control and acquire propellant in low gravity environments rely on liquid surface tension devices which employ vanes, fine screen mesh channels and baskets. These devices trap and direct propellant to areas where it's needed and have been used routinely with storable (non-cryogenic) propellants. However, almost no data exists r,egarding their operation in cryogenics and the use of such devices confronts designers with a multitude of significant technology issues. Typical problems include a sensitivity to screen dry out (due to thermal loads and pressurant gas) and momentary adverse accelerations (generated from either internal or external sources). Any of these problems can potentially cause the acquisition systems to ingest or develop vapor and fail. The use of lightweight high field strength magnets may offer a valuable means of augmenting traditional systems potentially mitigating or at least easing operational requirements. Two potential uses of magnetic fields include: 1) strategically positioning magnets to keep vent ports clear of liquid (enabling low G vented fill operations), and 2) placing magnets in the center or around the walls of the tank to create an insulating vapor pocket (between the liquid and the tank wall) which could effectively lower heat transfer to the liquid (enabling increased storage time).

  3. Crystal-Oriented Bi4Ti3O12 Ceramics Fabricated by High-Magnetic-Field Method

    Microsoft Academic Search

    Yutaka Doshida; Koichiro Tsuzuku; Hiroshi Kishi; Atsushi Makiya; Satoshi Tanaka; Keizo Uematsu; Tsunehisa Kimura

    2004-01-01

    The effect of powder properties on the degree of crystal orientation of Bi4Ti3O12 (BIT) ceramics fabricated by a high-magnetic-field method was investigated. As expected, the degree of orientation of BIT ceramics exhibited little dependence on the crystallinity of the powder, and depended on the particle size of the powder. The degree of orientation increased up to 0.96 when the particle

  4. Is the blind cave salamander Proteus anguinus equiped for magnetic orientation ?

    NASA Astrophysics Data System (ADS)

    Bouquerel, H.; Valet, J. P.

    2003-04-01

    The Proteus anguinus is a blind cave salamander which can develop the ability of using the earth’s magnetic field for orientation and navigation. It has been shown that the strength of the geomagnetic field is not strong enough to excite the electroreceptors of these animals through induction mechanism so that the most likely hypothesis is that they would use cristals of magnetite as permanent magnets. We have been looking for evidence of remanent magnetism in several proteus collected from the underground CNRS laboratory at Moulis (France). Because the level of natural remanent magnetization, if any, was too low to be measured with confidence using a 3 axis squid 2G magnetometer (even bringing the animals as close as possible to the sensors), we stepwise remagnetized the samples between 0.2 and 1.2T. Measurements were performed in different parts of three proteus bodies. No significant magnetization was detected in the head, most of the signal being concentrated in the lower body of the animal. Saturation was attained after 0.2T while stepwise demagnetization by alternating field showed that most magnetization was removed after 40 mT (medium destructive field, MDF of about 10 mT), which is typical of magnetite. Independent measurements of clay soils taken from the surrounding immediate environment of the animals reveal a different magnetic signature for saturation, MDF and viscosity. Thus there is no apparent and direct link between food absorbed from their environment and the magnetic remamence of the animals. New experiments are currently in progress to determine whether magnetite is the unique magnetic carrier and also to provide better clue about the magnetic granulometry and its distribution.

  5. Magnetic-field-induced orientation of superconducting MgB2 crystallites determined by x-ray diffraction

    E-print Network

    Vakni, David

    . The orientation of the crystals with the ab plane parallel to the magnetic field at all temperatures below Tc,13 For a crystal with = H in a field along the c axis, the vortex energy is given by 0/4 ab 2 within a factor= , the theory predicts that the torque should tend to orient crystals with their ab plane parallel

  6. A simple theory for optimizing finite width ELF magnetic field shields for minimum dependence on source orientation

    Microsoft Academic Search

    Pablo Moreno; Robert G. Olsen

    1997-01-01

    The effectiveness of single layer, finite width, planar extremely low frequency (ELF) magnetic field shields is strongly dependent upon the orientation of the field sources. Since source information is difficult to obtain, the issue of designing shields which are independent of source orientation is important. Here, a simple analytic model for shielding by multiple layer, finite width, planar shields constructed

  7. Chapter 23: Magnetic Flux and Faraday's Law of Induction 3. The image shows a rectangular loop oriented 42 degrees from a magnetic field.

    E-print Network

    Kioussis, Nicholas

    oriented 42 degrees from a magnetic field. Solve equation 23-1 for the magnetic field. Calculate the magnetic field: ( )( ) 5 2 4.8 10 Tm 0.020 T cos 0.051 m 0.068 m cos47 B A - × = = = ° 4. A house has a floor of dimensions 22 m by 18 m. The local magnetic field due to Earth has a horizontal component 2

  8. Oscillator strength spectrum of hydrogen in strong magnetic and electric fields with arbitrary mutual orientation

    NASA Astrophysics Data System (ADS)

    Guan, Xiaoxu

    2006-08-01

    We present oscillator strength spectra of the hydrogen Balmer ? series in crossed strong magnetic and electric fields. Field strength regimes of interest ( ??0.02a.u. and F?1×108V/m ) are the characteristic strengths observed on the surface of white dwarf stars. Based on the pseudospectral discretization technique, two independent methods have been developed to achieve reliable oscillator strengths in crossed fields. The effect of relative orientation between the magnetic and electric fields is clarified. Compared to the parallel configuration, we have observed that for the field strength regimes of interest, the perpendicular component of electric fields only results in a weaker coupling between the states belonging to the different subspaces of magnetic quantum numbers. This observation explains why the spectrum of oscillator strengths in crossed electric and magnetic fields with arbitrary mutual orientation shows similar behavior compared to that in parallel fields. However, a careful analysis shows that the two stronger transition lines at 5546 and 5620Å previously attributed to the Balmer ? series are now identified to belong to the Balmer ? series. An effective scheme has also been suggested to calculate the bound-free opacities of hydrogen atoms in crossed fields.

  9. Cosmic ray pressure driven magnetic field amplification: dimensional, radiative and field orientation effects

    NASA Astrophysics Data System (ADS)

    Downes, T. P.; Drury, L. O'C.

    2014-10-01

    Observations of non-thermal emission from several supernova remnants suggest that magnetic fields close to the blastwave are much stronger than would be naively expected from simple shock compression of the field permeating the interstellar medium (ISM). We investigate in some detail a simple model based on turbulence generation by cosmic ray pressure gradients. Previously, this model was investigated using 2D magnetohydrodynamic simulations. Motivated by the well-known qualitative differences between 2D and 3D turbulence, we further our investigations of this model using both 2D and 3D simulations to study the influence of the dimensionality of the simulations on the field amplification achieved. Further, since the model implies the formation of shocks which can, in principle, be efficiently cooled by collisional cooling, we include such cooling in our simulations to ascertain whether it could increase the field amplification achieved. Finally, we examine the influence of different orientations of the magnetic field with respect to the normal of the blastwave. We find that dimensionality has a slight influence on the overall amplification achieved, but a significant impact on the morphology of the amplified field. Collisional cooling has surprisingly little impact, primarily due to the short time which any element of the ISM resides in the precursor region for supernova blastwaves. Even allowing for a wide range of orientations of the magnetic field, we find that the magnetic field can be expected to be amplified by, on average, at least an order of magnitude in the precursors of supernova blastwaves.

  10. Influence of nonuniform magnetic fields on orientation of plant seedlings in microgravity conditions.

    PubMed

    Nechitailo, G S; Mashinsky, A L; Kuznetsov, A A; Chikov, V M; Kuznetsov, O A

    2001-01-01

    Experiments on the spatial behavior of the flax (Linum usitatissimum, L.) seedlings in a nonuniform magnetic field were conducted on the orbital space stations "Salut" and "Mir". This field can displace sensory organelles (statoliths) inside receptor cells and such displacement should cause a physiological reaction of the plant-tropistic curvature. Experiments were conducted in the custom-built "Magnetogravistat" facility, where seeds were germinated and grown for 3-4 days in a magnetic field with the dynamic factor grad (H2/2) approximately equal to 10(7) Oe2/cm, then fixed on orbit and returned to Earth for analysis. It was found, that 93% of the seedlings were oriented in the field consistently with curvature in response to displacement of statoliths along the field gradient by ponderomotive magnetic forces, while control seedlings grew in the direction of the initial orientation of the seed. This suggests, that gravity receptors of plants recognized magnetic forces on statoliths as gravity, and that gravity stimulus can be substituted for plants by a force of a different physical nature. PMID:11803966

  11. Influence of nonuniform magnetic fields on orientation of plant seedlings in microgravity conditions

    NASA Astrophysics Data System (ADS)

    Nechitailo, G. S.; Mashinsky, A. L.; Kuznetsov, A. A.; Chikov, V. M.; Kuznetsov, O. A.

    2001-01-01

    Experiments on the spatial behavior of the flax ( Linum usitatissimum, L.) seedlings in a nonuniform magnetic field were conducted on the orbital space stations «Salutå and «Mirå. This field can displace sensory organelles (statoliths) inside receptor cells and such displacement should cause a physiological reaction of the plant - tropistic curvature. Experiments were conducted in the custom-built «Magnetogravistatå facility, where seeds were germinated and grown for 3-4 days in a magnetic field with the dynamic factor grad(H 2/2)? 10 7 Oe 2/cm, then fixed on orbit and returned to Earth for analysis. It was found, that 93% of the seedlings were oriented in the field consistently with curvature in response to displacement of statoliths along the field gradient by ponderomotive magnetic forces, while control seedlings grew in the direction of the initial orientation of the seed. This suggests, that gravity receptors of plants recognized magnetic forces on statoliths as gravity, and that gravity stimulus can be substituted for plants by a force of a different physical nature.

  12. Wind and sky as compass cues in desert ant navigation

    NASA Astrophysics Data System (ADS)

    Müller, Martin; Wehner, Rüdiger

    2007-07-01

    While integrating their foraging and homing paths, desert ants, Cataglyphis fortis, depend on external compass cues. Whereas recent research in bees and ants has focused nearly exclusively on the polarization compass, two other compass systems—the sun compass and the wind (anemo) compass—as well as the mutual interactions of all these compass systems have received little attention. In this study, we show that of the two visual compass systems, it is only the polarization compass that invariably outcompetes the wind compass, while the sun compass does so only under certain conditions. If the ants are experimentally deprived of their polarization compass system, but have access simultaneously to both their sun compass and their wind compass, they steer intermediate courses. The intermediate courses shift the more towards the wind compass course, the higher the elevation of the sun is in the sky.

  13. Wind and sky as compass cues in desert ant navigation.

    PubMed

    Müller, Martin; Wehner, Rüdiger

    2007-07-01

    While integrating their foraging and homing paths, desert ants, Cataglyphis fortis, depend on external compass cues. Whereas recent research in bees and ants has focused nearly exclusively on the polarization compass, two other compass systems--the sun compass and the wind (anemo) compass--as well as the mutual interactions of all these compass systems have received little attention. In this study, we show that of the two visual compass systems, it is only the polarization compass that invariably outcompetes the wind compass, while the sun compass does so only under certain conditions. If the ants are experimentally deprived of their polarization compass system, but have access simultaneously to both their sun compass and their wind compass, they steer intermediate courses. The intermediate courses shift the more towards the wind compass course, the higher the elevation of the sun is in the sky. PMID:17361400

  14. Social Compass 60(1) 115133

    E-print Network

    Paris-Sud XI, Université de

    Social Compass 60(1) 115­133 © The Author(s) 2012 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0037768612471770 scp.sagepub.com social compass The politics of religious dualism: Naim'Ascq Cedex, France. Email: albert.doja@univ-lille1.fr 471770SCP60110.1177/0037768612471770Social Compass

  15. Self-Compassion and Interpersonal Cognitive Distortions

    ERIC Educational Resources Information Center

    Akin, Ahmet

    2010-01-01

    The purpose of this study is to examine the relationships between self-compassion and interpersonal cognitive distortions. Participants were 338 university students. In this study, the Self-compassion Scale and the Interpersonal Cognitive Distortions Scale were used. The relationships between self-compassion and interpersonal cognitive distortions…

  16. Self-Compassion and Automatic Thoughts

    ERIC Educational Resources Information Center

    Akin, Ahmet

    2012-01-01

    The aim of this research is to examine the relationships between self-compassion and automatic thoughts. Participants were 299 university students. In this study, the Self-compassion Scale and the Automatic Thoughts Questionnaire were used. The relationships between self-compassion and automatic thoughts were examined using correlation analysis…

  17. Automated Object-Oriented Simulation Framework for Modelling of Superconducting Magnets at CERN

    E-print Network

    Maciejewski, Micha?; Bartoszewicz, Andrzej

    The thesis aims at designing a flexible, extensible, user-friendly interface to model electro thermal transients occurring in superconducting magnets. Simulations are a fundamental tool for assessing the performance of a magnet and its protection system against the effects of a quench. The application is created using scalable and modular architecture based on object-oriented programming paradigm which opens an easy way for future extensions. What is more, each model composed of thousands of blocks is automatically created in MATLAB/Simulink. Additionally, the user is able to automatically run sets of simulations with varying parameters. Due to its scalability and modularity the framework can be easily used to simulate wide range of materials and magnet configurations.

  18. Vanderbilt Kennedy Center Orientation

    E-print Network

    Sarkar, Nilanjan

    2013-14 Vanderbilt Kennedy Center Orientation Manual A Guide to History, Programs, Procedures, and Training #12;Page | 1 Welcome to the Vanderbilt Kennedy Center! You may be here because you are a new Kennedy Center is an exciting, innovative organization where caring, compassion, professional expertise

  19. Meson spectroscopy with COMPASS

    E-print Network

    Frank Nerling; for the COMPASS collaboration

    2010-12-02

    The COMPASS fixed-target experiment at CERN SPS is dedicated to the study of hadron structure and dynamics. In the physics programme using hadron beams, the focus is on the detection of new states, in particular the search for $J^{PC}$ exotic states and glueballs. After a short pilot run in 2004 (190 GeV/c negative pion beam, lead target), we started our hadron spectroscopy programme in 2008 by collecting an unprecedented statistics with a negative hadron beam (190 GeV/c) on a liquid hydrogen target. A similar amount of data with positive hadron beam (190 GeV/c) has been taken in 2009, as well as some additional data with negative beam on nuclear targets. The spectrometer features a large angular acceptance and high momentum resolution and also good coverage by electromagnetic calorimetry, crucial for the detection of final states involving $\\pi^0$ or $\\eta$. A first important result is the observation of a significant $J^{PC}$ spin exotic signal consistent with the disputed $\\pi_1(1600)$ in the pilot run data. This result was recently published. We present an overview of the status of various ongoing analyses on the 2008/09 data.

  20. Delta G from Compass

    E-print Network

    Krzysztof Kurek

    2006-07-26

    Measurements of the gluon polarization $\\frac{\\Delta G}{G}$ via the open charm channel and based on the helicity asymmetry of large transverse-momentum hadrons in the final state are presented. The data have been collected in the years 2002-2004 by the COMPASS experiment at CERN using a 160 GeV/c polarized muon beam scattered off a polarized $^6$LiD target. The new result for $\\frac{\\Delta G}{G}$ from the charm channel is $-0.57 \\pm 0.41 (stat.)$ at $x_G \\simeq 0.15$ and scale $\\mu^2 \\simeq 13 $ (GeV/c)$^2$. The gluon polarization from high-$p_T$ hadron pairs is $\\frac{\\Delta G}{G} = 0.016\\pm 0.058 (stat.)\\pm 0.055 (syst.)$ at $x_G \\simeq 0.085^{+0.07}_{-0.035}$ ($Q^2 < 1$ (GeV/c)$^2$ and $\\mu^2 \\simeq 3$ (GeV/c)$^2$)

  1. A spot check for assessing static orientation consistency of inertial and magnetic sensing units.

    PubMed

    Picerno, Pietro; Cereatti, Andrea; Cappozzo, Aurelio

    2011-03-01

    Despite the widespread use of Magnetic and Inertial Measurement Units (MIMUs) for movement reconstruction, only a few studies have tackled issues related to their accuracy. It has been proved that their performance decreases over a period of use since calibration parameters become no longer effective. Good practice rules recommend to assess, prior to any experimental session, the instrumental errors associated to the relevant measures. Aim of this study was to provide a practical and reproducible spot check for assessing the performance of MIMUs in terms of consistency in determining their orientation with respect to a common (inter-MIMUs consistency, IC) and invariant (self-MIMU consistency, SC) global frame. IC was assessed by verifying the hypothesis that the orientation of 9 MIMUs aligned to each other on a rigid Plexiglas plank coincided at any orientation of the plank. SC was assessed separately by verifying differences between measured and imposed known rotations imparted to each MIMU. The orientation of MIMUs relative to the global frame was expressed in terms of quaternion. IC test showed that MIMUs defined their orientation differently. This difference was not constant but varied according to the plank's orientation. The least consistent MIMU showed discrepancy up to 5.7°. SC test confirmed the same MIMU as that affected by the highest inaccuracy (8.4°), whereas it revealed errors within limits (1°) in correspondence to other MIMUs. A tool has been proposed that allows the users to be aware of the errors that may be expected when using MIMUs for the estimate of absolute and relative segments kinematics. PMID:21227693

  2. Nucleon spin structure studies at COMPASS

    SciTech Connect

    Marchand, Claude [CEA/DAPNIA/SPhN, CE Saclay, F-91191 Gif-sur-Yvette CEDEX (France)

    2006-02-11

    One of the main goal of the COMPASS experiment at CERN is the study of the spin structure of the nucleon in DIS, by scattering 160 GeV polarized muon beam on a longitudinally (or transversely) polarized 6LiD target. Besides the scattered muon, the particles produced in the deep inelastic scattering are detected by a two stage magnetic spectrometer equipped with state of the art tracking and particle ID detectors.The emphasis of COMPASS muon program is the direct determination of the gluon polarization {delta}G/G, accessed via asymmetries involving photon-gluon fusion mechanism (PGF). Both open charm production (detecting D0's), as well as production of height pT hadron pairs are used to tag PGF. Preliminary results for {delta}G/G based on the analysis of 2002 and 2003 data are shown. In addition, improved measurement of the deuteron structure function g{sub 1}{sup d} at small x, as well as studies of transverse distribution functions in the deuteron by measuring Collins and Sivers azimuthal asymmetries, are reported.

  3. Transverse Spin Physics at COMPASS

    E-print Network

    Christian Schill; for the COMPASS collaboration

    2010-09-08

    The investigation of transverse spin and transverse momentum effects in deep inelastic scattering is one of the key physics programs of the COMPASS collaboration. Three channels have been analyzed at COMPASS to access the transversity distribution function: The azimuthal distribution of single hadrons, involving the Collins fragmentation function, the azimuthal dependence of the plane containing hadron pairs, involving the two-hadron interference fragmentation function, and the measurement of the transverse polarization of Lambda hyperons in the final state. Azimuthal asymmetries in unpolarized semi-inclusive deep-inelastic scattering give important information on the inner structure of the nucleon as well, and can be used to estimate both the quark transverse momentum k_T in an unpolarized nucleon and to access the so-far unmeasured Boer-Mulders function. COMPASS has measured these asymmetries using spin-averaged 6LiD data.

  4. Transverse Spin Physics at COMPASS

    E-print Network

    Federica Sozzi; for the COMPASS Collaboration

    2009-02-02

    The study of transverse spin effects is part of the scientific program of COMPASS, a fixed target experiment at the CERN SPS. COMPASS investigates the transversity PDFs in semi-inclusive DIS, using a longitudinally polarized muon beam of 160 GeV/c impinging on a transversely polarized target. From 2002 to 2004, data have been collected using a $^6$LiD target transversely polarized. Transversity has been measured using different quark polarimeters: the azimuthal distribution of single hadrons, the azimuthal dependence of the plane containing hadron pairs, and the measurement of the transverse polarization of baryons ($\\Lambda$ hyperons). All the asymmetries have been found to be small, and compatible with zero, a result which has been interpreted as a cancellation between the u and d-quark contributions. In 2007 COMPASS has taken data using a NH$_3$ polarized proton target which will give complementary information on transverse spin effects.

  5. Valence Quarks Polarization from COMPASS

    E-print Network

    A. Korzenev

    2007-04-26

    A first evaluation of the polarized valence quark distribution $\\Delta u_v(x)+\\Delta d_v(x)$ from the COMPASS experiment (CERN/SPS) is presented. The data were collected by COMPASS in the years 2002--2004 using a 160 GeV polarized muon beam scattered off a large polarized $^6$LiD target and cover the range $1< Q^2 < 100$ GeV$^2$ and $0.006

  6. Orientation of hatchling loggerhead sea turtles to regional magnetic fields along a transoceanic migratory pathway.

    PubMed

    Fuxjager, Matthew J; Eastwood, Brian S; Lohmann, Kenneth J

    2011-08-01

    Young loggerhead sea turtles (Caretta caretta) from the east coast of Florida, USA, undertake a transoceanic migration around the North Atlantic Gyre, the circular current system that flows around the Sargasso Sea. Previous experiments indicated that loggerhead hatchlings, when exposed to magnetic fields replicating those that exist at five widely separated locations along the migratory pathway, responded by swimming in directions that would, in each case, help turtles remain in the gyre and advance along the migratory route. In this study, hatchlings were exposed to several additional magnetic fields that exist along or outside of the gyre's northern boundary. Hatchlings responded to fields that exist within the gyre currents by swimming in directions consistent with their migratory route at each location, whereas turtles exposed to a field that exists north of the gyre had an orientation that was statistically indistinguishable from random. These results are consistent with the hypothesis that loggerhead turtles entering the sea for the first time possess a navigational system in which a series of regional magnetic fields sequentially trigger orientation responses that help steer turtles along the migratory route. By contrast, hatchlings may fail to respond to fields that exist in locations beyond the turtles' normal geographic range. PMID:21753042

  7. The impact of turbulence and magnetic field orientation on star forming filaments

    E-print Network

    Seifried, D

    2015-01-01

    We present simulations of collapsing filaments studying the impact of turbulence and magnetic field morphologies on their evolution and star formation properties. We vary the mass per unit length of the filaments as well as the orientation of the magnetic field with respect to the major axis. We find that the filaments, which have no or a perpendicular magnetic field, typically reveal a smaller width than the universal width of 0.1 pc proposed by e.g. Arzoumanian et al. 2011. We show that this also holds in the presence of supersonic turbulence and that accretion driven turbulence is too weak to stabilize the filaments along their radial direction. On the other hand, we find that a magnetic field that is parallel to the major axis can stabilize the filament against radial collapse resulting in widths of 0.1 pc. Furthermore, depending on the filament mass and magnetic field configuration, gravitational collapse and fragmentation in filaments occurs either in an edge-on way, uniformly distributed across the ent...

  8. Variable-State-Dimension Kalman-based Filter for orientation determination using inertial and magnetic sensors.

    PubMed

    Sabatini, Angelo Maria

    2012-01-01

    In this paper a quaternion-based Variable-State-Dimension Extended Kalman Filter (VSD-EKF) is developed for estimating the three-dimensional orientation of a rigid body using the measurements from an Inertial Measurement Unit (IMU) integrated with a triaxial magnetic sensor. Gyro bias and magnetic disturbances are modeled and compensated by including them in the filter state vector. The VSD-EKF switches between a quiescent EKF, where the magnetic disturbance is modeled as a first-order Gauss-Markov stochastic process (GM-1), and a higher-order EKF where extra state components are introduced to model the time-rate of change of the magnetic field as a GM-1 stochastic process, namely the magnetic disturbance is modeled as a second-order Gauss-Markov stochastic process (GM-2). Experimental validation tests show the effectiveness of the VSD-EKF, as compared to either the quiescent EKF or the higher-order EKF when they run separately. PMID:23012502

  9. Orientation and Strain Dependence of the Magnetic Phase Separation at Perovskite Cobaltite Interfaces

    NASA Astrophysics Data System (ADS)

    Bose, S.; Sharma, M.; Torija, M. A.; Gazquez, J.; Varela, M.; Ambaye, H.; Goyette, R.; Lauter, V.; Fitzsimmons, M. R.; Schmitt, J.; Leighton, C.

    2013-03-01

    We recently showed that the degraded magnetic and electronic properties in very thin STO(001)/La1-xSrxCoO3 films is due to a form of magnetic phase separation. This is primarily due to the strain driven accumulation of O vacancies near the interface. In this work we demonstrate how this understanding allows us to engineer these interfacial properties via crystallographic orientation and strain control. Using PNR, magnetometry and transport, we show how this degradation can be significantly mitigated by using LAO(001) and STO(110) substrates cf. STO(001). PNR on 400Å x =0.28 films reveals an interfacial layer with suppressed magnetism on all three substrates. However, while this layer is 150Å on STO(001), it extends at most to 30Å on LAO(001) and STO(110). Transport measurements on x =0.5 films show that at a thickness of ~ 55Å, films on STO(110) and LAO(001) exhibit AMR whereas films on STO(001) are dominated by inter-cluster GMR. Finally, thickness dependent magnetometry shows that the magnetic order deteriorates more quickly on STO(001) than on LAO(001) and STO(110). Our work thus opens up a possible new route to tailor interfacial magneto-electronic properties in oxide heterostructures. We recently showed that the degraded magnetic and electronic properties in very thin STO(001)/La1-xSrxCoO3 films is due to a form of magnetic phase separation. This is primarily due to the strain driven accumulation of O vacancies near the interface. In this work we demonstrate how this understanding allows us to engineer these interfacial properties via crystallographic orientation and strain control. Using PNR, magnetometry and transport, we show how this degradation can be significantly mitigated by using LAO(001) and STO(110) substrates cf. STO(001). PNR on 400Å x =0.28 films reveals an interfacial layer with suppressed magnetism on all three substrates. However, while this layer is 150Å on STO(001), it extends at most to 30Å on LAO(001) and STO(110). Transport measurements on x =0.5 films show that at a thickness of ~ 55Å, films on STO(110) and LAO(001) exhibit AMR whereas films on STO(001) are dominated by inter-cluster GMR. Finally, thickness dependent magnetometry shows that the magnetic order deteriorates more quickly on STO(001) than on LAO(001) and STO(110). Our work thus opens up a possible new route to tailor interfacial magneto-electronic properties in oxide heterostructures. Work supported by NSF and DOE; at ORNL by US DOE-BES MS&E Div; at UCM by ERC Starting Investigator Award

  10. The COMPASS Polarized Target in 2006 and 2007

    SciTech Connect

    Doshita, N.; Iwata, T.; Kondo, K.; Michigami, T. [Department of Physics, Faculty of Science, Yamagata University, 990-8560 Yamagata (Japan); Ball, J.; Magnon, A.; Marchand, C. [CEA Saclay DAPNIA, 91191 Gif-sur-Yvette (France); Baum, G. [Physics Department, University of Bielefeld, 33501 Bielefeld (Germany); Gautheron, F. [Physics Department, University of Bielefeld, 33501 Bielefeld (Germany); Physics Department, University of Bochum, 44780 Bochum (Germany); Goertz, St. [Physikalisches Institut, University of Bonn, 53115 Bonn (Germany); Hasegawa, T.; Matsuda, T. [Faculty of Engineering, Miyazaki University, 889-2192 Miyazaki (Japan); Heckmann, J.; Hess, Ch.; Kisselev, Y.; Koivuniemi, J.; Meyer, W.; Radtke, E.; Reicherz, G. [Physics Department, University of Bochum, 44780 Bochum (Germany); Horikawa, N. [Research Institute for Science and Technology, Chubu University, 487-8501 Kasugai, (Japan)] (and others)

    2008-02-06

    The COMPASS experiment has been taking data since 2002. Its polarized target was upgraded during the 2005 CERN SPS shutdown. With the high acceptance magnet we obtained +56.0% and -53.0% deuteron polarization in {sup 6}LiD. In 2007 ammonia is used as a proton target which has a relaxation time of {approx}4000 h at 0.6 T.

  11. The Magnetic Field

    NSDL National Science Digital Library

    Jeffrey Barker

    This demonstration of the magnetic field lines of Earth uses a bar magnet, iron filings, and a compass. The site explains how to measure the magnetic field of the Earth by measuring the direction a compass points from various points on the surface. There is also an explanation of why the north magnetic pole on Earth is actually, by definition, the south pole of a magnet.

  12. Magnetic anisotropies in (210)-oriented bismuth substituted iron garnet thin films

    NASA Astrophysics Data System (ADS)

    Nistor, I.; Holthaus, C.; Tkachuk, S.; Mayergoyz, I. D.; Krafft, C.

    2007-05-01

    The liquid phase epitaxy growth and characterization of single crystal (210)-oriented thin garnet films with Bi substitution up to 1.5at./f.u. is reported. These epitaxial films exhibit an easy plane of magnetization which is inclined with respect to the film plane, making them uniquely suitable for garnet-based magneto-optic imagers (MOIs). In order to identify the optimal growth conditions to attain the highest sensitivity of such MOIs, the chemical composition of the films is discussed in relation with their magnetic and optic properties. It has been demonstrated that the increase in the amount of Pr tends to increase the in-plane orthorhombic anisotropy field HKi, while the rare-earth substitution by Bi has a strong effect on the canted orthorhombic anisotropy Kyz. The best MOI film had a saturation field of 130Oe and a sensitivity of 175deg /A.

  13. Studies of TMDs at COMPASS

    E-print Network

    H. Wollny; for the COMPASS collaboration

    2010-08-03

    Transverse spin and transverse momentum distribution functions of the constituents of the nucleon are a crucial input for a complete description of the nucleon. COMPASS measured such for longitudinally and transversely polarized deuterons and protons. In the following we will focus on recent results from the 2007 transverse proton data and on the results for unpolarized deuterons.

  14. Envy and Compassion in Tournaments

    Microsoft Academic Search

    Christian Grund; Dirk Sliwka

    2005-01-01

    Many experiments and field studies indicate that most individuals are not purely motivated by material self-interest but also care about the well being of others. In this paper, we examine tournaments among inequity averse agents, who dislike disadvantageous inequity (envy) and advantageous inequity (compassion). It turns out that inequity averse agents exert higher efforts than purely self-interested agents for a

  15. Nucleon Transverse Structure at COMPASS

    E-print Network

    Nour Makke

    2014-12-15

    COMPASS is a fixed target experiment at CERN. Part of its physics programme is dedicated to study the transverse spin and the transverse momentum structure of the nucleon using SIDIS. For these measurements, data have been collected using transversely polarised proton and deuteron targets. A selection of recent measurements of azimuthal asymmetries using data collected with transversely polarised protons is presented.

  16. Impact of a high magnetic field on the orientation of gravitactic unicellular organisms--a critical consideration about the application of magnetic fields to mimic functional weightlessness.

    PubMed

    Hemmersbach, Ruth; Simon, Anja; Waßer, Kai; Hauslage, Jens; Christianen, Peter C M; Albers, Peter W; Lebert, Michael; Richter, Peter; Alt, Wolfgang; Anken, Ralf

    2014-03-01

    The gravity-dependent behavior of Paramecium biaurelia and Euglena gracilis have previously been studied on ground and in real microgravity. To validate whether high magnetic field exposure indeed provides a ground-based facility to mimic functional weightlessness, as has been suggested earlier, both cell types were observed during exposure in a strong homogeneous magnetic field (up to 30 T) and a strong magnetic field gradient. While swimming, Paramecium cells were aligned along the magnetic field lines; orientation of Euglena was perpendicular, demonstrating that the magnetic field determines the orientation and thus prevents the organisms from the random swimming known to occur in real microgravity. Exposing Astasia longa, a flagellate that is closely related to Euglena but lacks chloroplasts and the photoreceptor, as well as the chloroplast-free mutant E. gracilis 1F, to a high magnetic field revealed no reorientation to the perpendicular direction as in the case of wild-type E. gracilis, indicating the existence of an anisotropic structure (chloroplasts) that determines the direction of passive orientation. Immobilized Euglena and Paramecium cells could not be levitated even in the highest available magnetic field gradient as sedimentation persisted with little impact of the field on the sedimentation velocities. We conclude that magnetic fields are not suited as a microgravity simulation for gravitactic unicellular organisms due to the strong effect of the magnetic field itself, which masks the effects known from experiments in real microgravity. PMID:24621307

  17. Kalman-Filter-Based Orientation Determination Using Inertial/Magnetic Sensors: Observability Analysis and Performance Evaluation

    PubMed Central

    Sabatini, Angelo Maria

    2011-01-01

    In this paper we present a quaternion-based Extended Kalman Filter (EKF) for estimating the three-dimensional orientation of a rigid body. The EKF exploits the measurements from an Inertial Measurement Unit (IMU) that is integrated with a tri-axial magnetic sensor. Magnetic disturbances and gyro bias errors are modeled and compensated by including them in the filter state vector. We employ the observability rank criterion based on Lie derivatives to verify the conditions under which the nonlinear system that describes the process of motion tracking by the IMU is observable, namely it may provide sufficient information for performing the estimation task with bounded estimation errors. The observability conditions are that the magnetic field, perturbed by first-order Gauss-Markov magnetic variations, and the gravity vector are not collinear and that the IMU is subject to some angular motions. Computer simulations and experimental testing are presented to evaluate the algorithm performance, including when the observability conditions are critical. PMID:22163689

  18. Magnetohydrodynamic Simulations of Hypersonic Flow over a Cylinder Using Axial- and Transverse-Oriented Magnetic Dipoles

    PubMed Central

    Guarendi, Andrew N.; Chandy, Abhilash J.

    2013-01-01

    Numerical simulations of magnetohydrodynamic (MHD) hypersonic flow over a cylinder are presented for axial- and transverse-oriented dipoles with different strengths. ANSYS CFX is used to carry out calculations for steady, laminar flows at a Mach number of 6.1, with a model for electrical conductivity as a function of temperature and pressure. The low magnetic Reynolds number (?1) calculated based on the velocity and length scales in this problem justifies the quasistatic approximation, which assumes negligible effect of velocity on magnetic fields. Therefore, the governing equations employed in the simulations are the compressible Navier-Stokes and the energy equations with MHD-related source terms such as Lorentz force and Joule dissipation. The results demonstrate the ability of the magnetic field to affect the flowfield around the cylinder, which results in an increase in shock stand-off distance and reduction in overall temperature. Also, it is observed that there is a noticeable decrease in drag with the addition of the magnetic field. PMID:24307870

  19. Kalman-filter-based orientation determination using inertial/magnetic sensors: observability analysis and performance evaluation.

    PubMed

    Sabatini, Angelo Maria

    2011-01-01

    In this paper we present a quaternion-based Extended Kalman Filter (EKF) for estimating the three-dimensional orientation of a rigid body. The EKF exploits the measurements from an Inertial Measurement Unit (IMU) that is integrated with a tri-axial magnetic sensor. Magnetic disturbances and gyro bias errors are modeled and compensated by including them in the filter state vector. We employ the observability rank criterion based on Lie derivatives to verify the conditions under which the nonlinear system that describes the process of motion tracking by the IMU is observable, namely it may provide sufficient information for performing the estimation task with bounded estimation errors. The observability conditions are that the magnetic field, perturbed by first-order Gauss-Markov magnetic variations, and the gravity vector are not collinear and that the IMU is subject to some angular motions. Computer simulations and experimental testing are presented to evaluate the algorithm performance, including when the observability conditions are critical. PMID:22163689

  20. Magnetohydrodynamic simulations of hypersonic flow over a cylinder using axial- and transverse-oriented magnetic dipoles.

    PubMed

    Guarendi, Andrew N; Chandy, Abhilash J

    2013-01-01

    Numerical simulations of magnetohydrodynamic (MHD) hypersonic flow over a cylinder are presented for axial- and transverse-oriented dipoles with different strengths. ANSYS CFX is used to carry out calculations for steady, laminar flows at a Mach number of 6.1, with a model for electrical conductivity as a function of temperature and pressure. The low magnetic Reynolds number (<1) calculated based on the velocity and length scales in this problem justifies the quasistatic approximation, which assumes negligible effect of velocity on magnetic fields. Therefore, the governing equations employed in the simulations are the compressible Navier-Stokes and the energy equations with MHD-related source terms such as Lorentz force and Joule dissipation. The results demonstrate the ability of the magnetic field to affect the flowfield around the cylinder, which results in an increase in shock stand-off distance and reduction in overall temperature. Also, it is observed that there is a noticeable decrease in drag with the addition of the magnetic field. PMID:24307870

  1. Observation of the effect of grain orientation on chromium segregation in longitudinal magnetic media

    SciTech Connect

    Risner, Juliet D. [Stanford University; Sinclair, Prof. Robert [Stanford University; Bentley, James [ORNL

    2006-01-01

    The nanoscale grain size of current hard disk media demands high-resolution methods for characterization. Therefore, high-resolution transmission electron microscopy (TEM), energy-filtered TEM (EFTEM) imaging, and nanoprobe energy-dispersive spectroscopy were chosen for the examination of Co{sub 84-x-y}Cr{sub 16}Pt{sub x}Ta{sub y} longitudinal hard disk media samples. Experiments were conducted to elucidate the relationship between nanoscale variations in grain-boundary composition and the atomic structure of the grain boundaries. Results show that Cr enriches the grain boundaries of the magnetic layer in all examined cases, but the addition of Ta greatly enhances this enrichment at some boundaries. Nanoprobe and EFTEM results show that enrichment varies according to the grain-boundary orientation of the hcp cobalt alloy crystals. Grains with tilt-boundary orientations near 0{sup o}, 30{sup o}, and 60{sup o}, found by measuring the angle between adjacent c-axis directions, show the least amount of segregation. Grains with tilt-boundary orientations near 15{sup o}, 45{sup o} and 75{sup o} show maximum amounts of Cr segregation. This trend exists in both CoCrTa and CoCrTaPt samples, and efforts to interpret the results within the context of hcp coincident site lattice theory are described.

  2. Integration of polarization and chromatic cues in the insect sky compass.

    PubMed

    el Jundi, Basil; Pfeiffer, Keram; Heinze, Stanley; Homberg, Uwe

    2014-06-01

    Animals relying on a celestial compass for spatial orientation may use the position of the sun, the chromatic or intensity gradient of the sky, the polarization pattern of the sky, or a combination of these cues as compass signals. Behavioral experiments in bees and ants, indeed, showed that direct sunlight and sky polarization play a role in sky compass orientation, but the relative importance of these cues are species-specific. Intracellular recordings from polarization-sensitive interneurons in the desert locust and monarch butterfly suggest that inputs from different eye regions, including polarized-light input through the dorsal rim area of the eye and chromatic/intensity gradient input from the main eye, are combined at the level of the medulla to create a robust compass signal. Conflicting input from the polarization and chromatic/intensity channel, resulting from eccentric receptive fields, is eliminated at the level of the anterior optic tubercle and central complex through internal compensation for changing solar elevations, which requires input from a circadian clock. Across several species, the central complex likely serves as an internal sky compass, combining E-vector information with other celestial cues. Descending neurons, likewise, respond both to zenithal polarization and to unpolarized cues in an azimuth-dependent way. PMID:24589854

  3. Orientation of snow buntings (Plectrophenax nivalis) close to the magnetic north pole

    PubMed

    Sandberg; BACkman; Ottosson

    1998-05-21

    Orientation experiments were performed with first-year snow buntings (Plectrophenax nivalis) during their autumn migration in a natural near-vertical geomagnetic field approximately 400 km away from the magnetic north pole. Migratory orientation of snow buntings was recorded using two different techniques: orientation cage tests and free-flight release experiments. Experiments were performed under clear skies, as well as under natural and simulated complete overcast. Several experimental manipulations were performed including an artificial shift of the E-vector direction of polarized light, depolarization of incoming light and a 4 h slow clock-shift experiment. The amount of stored fat proved to be decisive for the directional selections of the buntings. Fat individuals generally chose southerly mean directions, whereas lean birds selected northerly headings. These directional selections seemed to be independent of experimental manipulations of the buntings' access to visual cues even in the local near-vertical magnetic field. Under clear skies, the buntings failed to respond to either a deflection of the E-vector direction of polarized light or an experimental depolarization of incoming skylight. When tested under natural as well as simulated overcast, the buntings were still able to select a meaningful mean direction according to their fat status. Similarly, the free-flight release test under complete overcast resulted in a well-defined southsoutheast direction, possibly influenced by the prevailing light northwest wind. Clock-shift experiments did not yield a conclusive result, but the failure of these birds to take off during the subsequent free-flight release test may indicate some unspecified confusion effect of the treatment. PMID:9600868

  4. Sun-compass migration by Aurelia aurita (Scyphozoa): population retention and reproduction in Saanich Inlet, British Columbia

    Microsoft Academic Search

    W. M. Hamner; P. P. Hamner; S. W. Strand

    1994-01-01

    The scyphomedusa Aurelia aurita in Saanich Inlet, a north-south oriented fjord in British Columbia, uses a sun compass to migrate in a southeasterly direction during the day. When the sky is overcast and at night, A. aurita orients randomly and is dispersed passively by gentle tidal currents. The net result is daily reaggregation of medusae into enormous swarms along the

  5. Countering compassion fatigue: a requisite nursing agenda.

    PubMed

    Boyle, Deborah A

    2011-01-01

    Nurses have a longstanding history of witnessing the tragedy experienced by patients and families; however, their own reactions to profound loss and premature death have not been systematically addressed. There is a paucity of research describing interventions to prevent or minimize the ramifications of repeated exposure to traumatic events in the clinical workplace. Compassion fatigue is a contemporary label affixed to the concept of personal vicarious exposure to trauma on a regular basis. Yet this phenomenon of compassion fatigue lacks clarity. In this article, the author begins by describing compassion fatigue and distinguishing compassion fatigue from burnout. Next she discusses risk factors for, and the assessment of compassion fatigue. The need to support nurses who witness tragedy and workplace interventions to confront compassion fatigue are described. PMID:21800933

  6. Mechanism of orientation of stimulating currents in magnetic brain stimulation (abstract)

    NASA Astrophysics Data System (ADS)

    Ueno, S.; Matsuda, T.

    1991-04-01

    We made a functional map of the human motor cortex related to the hand and foot areas by stimulating the human brain with a focused magnetic pulse. We observed that each functional area in the cortex has an optimum direction for which stimulating currents can produce neural excitation. The present report focuses on the mechanism which is responsible for producing this anisotropic response to brain stimulation. We first obtained a functional map of the brain related to the left ADM (abductor digiti minimi muscles). When the stimulating currents were aligned in the direction from the left to the right hemisphere, clear EMG (electromyographic) responses were obtained only from the left ADM to magnetic stimulation of both hemisphere. When the stimulating currents were aligned in the direction from the right to the left hemisphere, clear EMG signals were obtained only from the right ADM to magnetic stimulation of both hemisphere. The functional maps of the brain were sensitive to changes in the direction of the stimulating currents. To explain the phenomena obtained in the experiments, we developed a model of neural excitation elicited by magnetic stimulation. When eddy currents which are induced by pulsed magnetic fields flow in the direction from soma to the distal part of neural fiber, depolarized area in the distal part are excited, and the membrane excitation propagates along the nerve fiber. In contrast, when the induced currents flow in the direction from the distal part to soma, hyperpolarized parts block or inhibit neural excitation even if the depolarized parts near the soma can be excited. The model explains our observation that the orientation of the induced current vectors reflect both the functional and anatomical organization of the neural fibers in the brain.

  7. Frustration and Entanglement in Compass and Spin-Orbital Models

    E-print Network

    Andrzej M. Ole?

    2014-10-24

    We review the consequences of intrinsic frustration of the orbital superexchange and of spin-orbital entanglement. While Heisenberg perturbing interactions remove frustration in the compass model, the lowest columnar excitations are robust in the nanoscopic compass clusters and might be used for quantum computations. Entangled spin-orbital states determine the ground states in some cases, while in others concern excited states and lead to measurable consequences, as in the $R$VO$_3$ perovskites. On-site entanglement for strong spin-orbit coupling generates the frustrated Kitaev-Heisenberg model with a rich magnetic phase diagram on the honeycomb lattice. Frustration is here reflected in hole propagation which changes from coherent in an antiferromagnet via hidden quasiparticles in zigzag and stripe phases to entirely incoherent one in the Kitaev spin liquid.

  8. Circuits and Magnetic Fields

    NSDL National Science Digital Library

    VU Bioengineering RET Program,

    Students use the same method as in the activity from lesson 2 of this unit to explore the magnetism due to electric current instead of a permanent magnet. Students use a compass and circuit to trace the magnetic field lines induced by the electric current moving through the wire. Students develop an understanding of the effect of the electrical current on the compass needle through the induced magnetic field and understand the complexity of a three dimensional field system.

  9. Preparation and characterization of Grain-Oriented Barium Titanate Ceramics Using Electrophoresis Deposition Method under A High Magnetic Field

    NASA Astrophysics Data System (ADS)

    Kita, T.; Kondo, S.; Takei, T.; Kumada, N.; Nakashima, K.; Fujii, I.; Wada, S.; Suzuki, T. S.; Uchikoshi, T.; Sakka, Y.; Miwa, Y.; Kawada, S.; Kimura, M.

    2011-10-01

    Barium titanate (BaTiO3) grain-oriented ceramics were prepared using electrophoresis deposition (EPD) method under high magnetic field of 12 T. First, BaTiO3 nanoparticles with high c/a ratio of 1.008 and size of 84 nm were prepared by two-step thermal decomposition method with barium titanyl oxalate nanoparticles. Using the BaTiO3 slurry, BaTiO3 nanoparticle accumulations were prepared by EPD method under high magnetic field. After binder burnout, the accumulations were sintered and BaTiO3 grain-oriented ceramics were prepared. Moreover, dielectric properties of their ceramics were investigated

  10. Dayside Magnetopause Transients Correlated with Changes of the Magnetosheath Magnetic Field Orientation

    NASA Technical Reports Server (NTRS)

    Tkachenko, O.; Safrankova, J.; Nemecek, Z.; Sibeck, D. G.

    2011-01-01

    The paper analyses one long-term pass (26 August 2007) of the THEMIS spacecraft across the dayside low-latitude magnetopause. THEMIS B, serving partly as a magnetosheath monitor, observed several changes of the magnetic field that were accompanied by dynamic changes of the magnetopause location and/or the structure of magnetopause layers observed by THEMIS C, D, and E, whereas THEMIS A scanned the inner magnetosphere. We discuss the plasma and the magnetic field data with motivation to identify sources of observed quasiperiodic plasma transients. Such events at the magnetopause are usually attributed to pressure pulses coming from the solar wind, foreshock fluctuations, flux transfer events or surface waves. The presented transient events differ in nature (the magnetopause surface deformation, the low-latitude boundary layer thickening, the crossing of the reconnection site), but we found that all of them are associated with changes of the magnetosheath magnetic field orientation and with enhancements or depressions of the plasma density. Since these features are not observed in the data of upstream monitors, the study emphasizes the role of magnetosheath fluctuations in the solar wind-magnetosphere coupling.

  11. Magnetism, magnetoresistance, and Shubnikov-de Haas oscillations in Na-implanted highly oriented pyrolitic graphite

    NASA Astrophysics Data System (ADS)

    Pires, R. F.; Pureur, P.; Behar, M.; Pimentel, J. L.; Schaf, J.; Kopelevich, Y.

    2012-05-01

    We report on magnetization, magnetoresistance, and Shubnikov-de Haas oscillations experiments in Na-implanted samples of highly oriented pyrolitic graphite (HOPG). Different ion fluences were applied so that samples with Na contents of 0.5, 1.0, 1.5, and 2.0 at. % were obtained in the implanted region. Ferromagnetic-like hysteresis was observed in magnetization experiments where the field was applied parallel to the graphene planes. The observed saturation moment increases systematically as a function of the implanted ion concentration up to Na 1 at. %, where it goes through a maximum before decreasing slightly towards Na 2 at. %. The planar magnetoresistance amplitude at fixed field and temperature closely correlates with the saturation magnetization data. This result suggests that the strong planar magnetoresistance in graphite is at least partially related to a spin dependent mechanism. The magnetoresistance experiments also reveal the occurrence of Shubnikov-de Haas oscillations. The characteristic frequencies and the effective masses could be estimated and do not depend on the Na concentration. The reported experiments show that the expressive enhancement observed in ferromagnetic-like response in Na-implanted HOPG is primarily due to point defects produced by the implantation process.

  12. Effect of copper precipitates on the stability of microstructures and magnetic properties of non-oriented electrical steels

    NASA Astrophysics Data System (ADS)

    Wu, Meng; Zeng, Yanping

    2015-10-01

    Non-oriented electrical steels with different amounts of copper were prepared and the microstructure and magnetic properties of each kind of steel were studied. The results show that there exist a large number of Cu-rich metastable precipitates in the hot-rolled bands of the steels containing copper. They not only can decrease the sensitivity of the microstructures and magnetic properties of the steels to the change of process parameters but also can significantly reduce the core loss of the steels by improving the recrystallization textures without obviously decreasing the magnetic induction. Therefore, it is possible to control the microstructures and then magnetic properties of non-oriented electrical steels by the copper precipitates.

  13. Single-crystal NMR approach for determining chemical shift tensors from powder samples via magnetically oriented microcrystal arrays

    NASA Astrophysics Data System (ADS)

    Song, Guangjie; Kusumi, Ryosuke; Kimura, Fumiko; Kimura, Tsunehisa; Deguchi, Kenzo; Ohki, Shinobu; Fujito, Teruaki; Simizu, Tadashi

    2015-06-01

    The single-crystal rotation technique was applied to magnetically oriented microcrystal arrays (MOMAs) of cellobiose (monoclinic) to determine the principal values and principal axes of the chemical shift tensors of C1 and C1? carbons. Rotations were performed about the magnetic ?1, ?2, and ?3 axes of MOMA, and the measurements were taken at six different orientations with respect to the applied magnetic field. Under these rotations, crowded peaks were reduced and the peaks for the C1 and C1? carbons were identified by comparing with simulation results. Six components of the chemical shift tensor expressed with respect to the magnetic ?1?2?3-frame were determined. The tensors thus obtained were transformed into those relative to the molecular frame.

  14. Penetrant-Indication-Measuring Compass

    NASA Technical Reports Server (NTRS)

    Schaefer, Lloyd

    1991-01-01

    Modified drafting compass well suited to measurement of length of crack or width of area stained by penetrant-dye-inspection method. Equipped with any of variety of standard curved or straight pointed tips. Modification consists in coating tips with dye that fluoresces light pink under same ultraviolet inspection light causing penetrant dye to fluoresce yellow green. Used in locations inaccessible to conventional fluorescent comparator. Eliminates errors of optical distortion in comparator, also eliminates errors of interpolation.

  15. Transverse Spin Effects at COMPASS

    SciTech Connect

    Wollny, H. [Physikalisches Institut der Albert-Ludwigs-Universitaet Freiburg, Hermann-Herder Str. 3, 79104 Freiburg (Germany)

    2009-08-04

    The measurement of transverse spin effects in semi-inclusive deep-inelastic scattering (SIDIS) is an important part of the COMPASS physics program. In the years 2002-2004 data was taken by scattering a 160 GeV/c muon beam off a transversely polarized deuteron target. In 2007, additional data was collected on a transversely polarized proton target. New preliminary results for the Collins and Sivers asymmetries from the analysis of the proton data are presented.

  16. The COMPASS data acquisition system

    Microsoft Academic Search

    H. Fischer; J. Franz; A. Grunemaier; F. H. Heinsius; M. Hoffmann; F. Karstens; W. Kastaun; K. Konigsmann; M. Niebuhr; R. Risken; T. Schmidt; H. Schmitt; A. Schweimler; M. V. Hodenberg; H. J. Urban

    2002-01-01

    A fully pipelined and massively parallel data acquisition system has been developed for the COMPASS experiment at CERN. The main requirements are to read 250000 detector channels at a trigger rate of up to 100 kHz. Such high rates are only possible when using a hit selection mechanism on the front-end combined with dead-time free readout. For this purpose, a

  17. Transverse Spin Effects at COMPASS

    E-print Network

    C. Schill

    2009-09-29

    The investigation of transverse spin and transverse momentum effects in deep inelastic scattering is one of the key physics programs of the COMPASS collaboration. In the years 2002-2004 COMPASS took data scattering 160 GeV muons on a transversely polarized 6LiD target. In 2007, a transversely polarized NH3 target was used. Three different channels to access the transversity distribution function have been analyzed: The azimuthal distribution of single hadrons, involving the Collins fragmentation function, the azimuthal dependence of the plane containing hadron pairs, involving the two-hadron interference fragmentation function, and the measurement of the transverse polarization of lambda hyperons in the final state. Transverse quark momentum effects in a transversely polarized nucleon have been investigated by measuring the Sivers distribution function. Azimuthal asymmetries in unpolarized semi-inclusive deep-inelastic scattering give important information on the inner structure of the nucleon as well, and can be used to estimate both the quark transverse momentum in an unpolarized nucleon and to access the so-far unmeasured Boer-Mulders function. COMPASS has measured these asymmetries using spin-averaged 6LiD data.

  18. Effect of magnetic field in rf sputtering on the crystal orientation and magnetic properties of Co-Cr perpendicular anisotropy films

    NASA Astrophysics Data System (ADS)

    Maeda, H.

    1983-05-01

    Co-23-wt. %-Cr alloy films with thicknesses of 0.3 to 2.5 ?m were deposited using a conventional rf diode sputtering system when a magnetic field Hs less than 90 Oe is applied during deposition. As Hs increases, the hcp c-axis orientation normal to the film plane develops and the half-angle width of the rocking curve of the (002) line ??50 reaches to 3.5 deg at Hs more than 40 Oe. The development of the orientation is strongly related to the concentration of O in the films, which is lower in the films deposited in a magnetic field than those in a nonmagnetic field. The magnetic properties such as perpendicular coercive force Hc? and saturation magnetization Ms strongly depend on the substrate temperature rather than Hs.

  19. Fiber optic compass development

    E-print Network

    Park, Kyongtae

    2005-11-01

    Fig. 2-8. Correction lens .............................................................................................. 13 Fig. 2-9. Barcode pattern with tapered gaps for determining pitch as well as Heading... Fig. 2-9. Barcode pattern with tapered gaps for determining pitch as well as heading 15 The ability of the system to determine pitch as well as magnetic heading makes use of the fact that the latitude of the focused spot on the outer surface...

  20. Magnetic moment of Ag-104(m) and the hyperfine magnetic field of Ag in Fe using nuclear magnetic resonance on oriented nuclei

    E-print Network

    V. V. Golovko; I. S. Kraev; T. Phalet; B. Delaure; M. Beck; V. Yu. Kozlov; S. Coeck; F. Wauters; P. Herzog; Ch. Tramm; D. Zakoucky; D. Venos; D. Srnka; M. Honusek; U. Koester; N. Severijns

    2010-06-30

    Nuclear magnetic resonance (NMR/ON) measurements with beta- and gamma-ray detection have been performed on oriented Ag-104(g,m) nuclei with the NICOLE He-3-He-4 dilution refrigerator setup at ISOLDE/CERN. For Ag-104(g) (I-pi = 5(+)) the gamma-NMR/ON resonance signal was found at nu = 266.70(5) MHz. Combining this result with the known magnetic moment for this isotope, the magnetic hyperfine field of Ag impurities in an Fe host at low temperature (field. Averaging all four values yields a new and precise value for the hyperfine field of Ag in Fe; that is, vertical bar B-hf(AgFe)vertical bar = 44.692(30) T. For Ag-104(m) (I-pi = 2(+)), the anisotropy of the beta particles provided the NMR/ON resonance signal at nu = 627.7(4) MHz. Using the new value for the hyperfine field of Ag in Fe, this frequency corresponds to the magnetic moment mu(Ag-104m) = +3.691(3) mu(N), which is significantly more precise than previous results. The magnetic moments of the even-A Ag102 -110 isotopes are discussed in view of the competition between the (pi g(9/2))(7/2+)(-3)(nu d(5/2)nu g(7/2))(5/2+) and the (pi g(9/2))(9/2+)(-3)(nu d(5/2)nu g(7/2))(5/2+) configurations. The magnetic moments of the ground and isomeric states of Ag-104 can be explained by an almost complete mixing of these two configurations.

  1. Impact of Nearby Adiabatic and Isothermal Barriers on the Thermal Characteristics of a Vertically Oriented Pot-Core Magnetic Component

    Microsoft Academic Search

    F. Farahmand; J. D. Lavers; F. P. Dawson

    2007-01-01

    The coupled problem of estimating the temperature rise due to the winding and core loss in a vertically oriented magnetic component is considered. The principle contributions in this paper are two-fold: 1) the coupling between the losses and thermal problems for the component is addressed accounting for the effects of nearby barriers and 2) the complication that the convection coefficient

  2. Parallel-End-Point Drafting Compass

    NASA Technical Reports Server (NTRS)

    Cronander, J.

    1986-01-01

    Parallelogram linkage ensures greater accuracy in drafting and scribing. Two members of arm of compass remain parallel for all angles pair makes with hub axis. They maintain opposing end members in parallelism. Parallelogram-linkage principle used on dividers as well as on compasses.

  3. Self-Compassion and Internet Addiction

    ERIC Educational Resources Information Center

    Iskender, Murat; Akin, Ahmet

    2011-01-01

    The purpose of this research is to examine the relationship of self-compassion and internet addiction. Participants were 261 university students who completed a questionnaire package that included the Self-compassion Scale and the Online Cognition Scale. The hypothesis model was tested through structural equation modeling. In correlation analysis,…

  4. Tunneling magnetoresistance in (001)-oriented FeCo/MgO/FeCo magnetic tunneling junctions grown by sputtering deposition

    SciTech Connect

    Moriyama, T.; Ni, C.; Wang, W.G.; Zhang, X.; Xiao, John Q. [Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States); Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716 (United States); Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States)

    2006-05-29

    Magnetic tunneling junctions (MTJs) with MgO tunnel barrier have been fabricated on both oriented and nonoriented buffer layers on Si(001) substrate by magnetron sputtering. FeCo/MgO/FeCo MTJs fabricated on oriented buffer layers show larger tunneling magnetoresistance (TMR) value up to 84% without high temperature postannealing, whereas those MTJs on nonoriented buffer layers show 45% of TMR. The high-resolution transmission electron microscopy images reveal an excellent morphology and very coherent crystal structure with FeCo(001)[110]/MgO(001)[100]/FeCo(001)[110] orientation. The results indicate that high TMR can be achieved without high temperature postannealing by sputtering deposition on appropriate oriented buffer layers.

  5. Never Too Young to Orienteer.

    ERIC Educational Resources Information Center

    Lavine, Carolyn

    1992-01-01

    Describes orienteering courses for children, including courses that introduce young children to the idea of navigating in the outdoors and courses that teach map and compass skills and problem-solving techniques to older children. Lists sources of information and references. (SV)

  6. Study and Simulation of Remote Sensing System: COMPACT Airborne Spectral Sensor (COMPASS)

    E-print Network

    Salvaggio, Carl

    1 Study and Simulation of Remote Sensing System: COMPACT Airborne Spectral Sensor (COMPASS) Paper............................................................................................ 5 COMPACT Airborne Spectral Sensor (COMPASS............................................................................................... 9 (FOUO) COMPASS Megacollect Data

  7. Magnetic domain structure and crystallographic orientation of electrical steels revealed by a forescatter detector and electron backscatter diffraction.

    PubMed

    Gallaugher, Matthew; Brodusch, Nicolas; Gauvin, Raynald; Chromik, Richard R

    2014-07-01

    The magnetic properties of non-oriented electrical steels (NOES) are an important factor in determining the efficiency of electric vehicle drivetrains. Due to the highly variable texture of NOES, the relationships between crystal orientation, the magnetic domain structure, and the final magnetic properties are complicated and not fully understood. In this study, a NOES sample was characterized with a method capable of imaging surface magnetic domains using scanning electron microscopy (SEM) with an electron backscatter diffraction (EBSD) system equipped with a forescatter detector. This method used type II magnetic contrast without a specialized SEM setup, and imaged with a resolution limit of approximately 250-300nm. The domain structure of the NOES sample was successfully related to ?, which was defined as the angle between the closest magnetic easy axis and the surface of the sample (the RD-TD plane). However, it was shown that if the easy axes were aligned between neighbouring grains with respect to the grain boundary normal, the domain structure could align with an easy axis that was not the closest to the surface, and complex domain structures could be become wider. This structure and width change of complex domain structures has not been previously observed from single crystal or large-grained material studies. The successful application of this method to reveal the influence of surrounding grains can be used to better understand the magnetic properties of NOES. PMID:24769020

  8. Mapping Magnetic Field Lines

    NSDL National Science Digital Library

    This is an activity about electromagnetism. Learners will use a compass to map the magnetic field lines surrounding a coil of wire that is connected to a battery. This activity requires a large coil or spool of wire, a source of electricity such as 3 D-cell batteries or an AC to DC power adapter, alligator-clipped wire, and magnetic compasses. This is the third lesson in the second session of the Exploring Magnetism teachers guide.

  9. Circles of Magnetism I

    NSDL National Science Digital Library

    2011-12-05

    In this activity related to magnetism and electricity, learners create a magnetic field that's stronger than the Earth's magnetic field. Learners use electric currents that are stronger than the field of the Earth to move a compass needle. The assembly is made using a lantern battery, heavy wire, a Tinkertoy™ set, and poster board and utilizes 4-6 small compasses and 2 electrical lead wires.

  10. Repeatability of functional anisotropy in navigated transcranial magnetic stimulation - coil-orientation versus response.

    PubMed

    Kallioniemi, Elisa; Könönen, Mervi; Julkunen, Petro

    2015-06-17

    Transcranial magnetic stimulation (TMS) can be used for evaluating the function of motor pathways. According to the principles of electromagnetism and electrophysiology, TMS activates those neurons that are suitably oriented with respect to the TMS-induced electric field. We hypothesized that TMS could potentially be able to evaluate the neuronal structure, although until now, this putative application has not been exploited. We have developed a TMS-based method to evaluate the function and structure of the motor cortex concurrently in a quantitative manner. This method produced a measure, the anisotropy index (AI), which is based on the motor-evoked potentials induced at different coil orientations. The AI was demonstrated to exhibit an association with both motor cortex excitability and neuronal structure. In the present study, we evaluated the repeatability (intrasession and intersession) of AI in three consecutive measurements. In addition, we studied the repeatability of the optimal coil angle in inducing motor-evoked potentials. Two of the measurements were conducted on the same stimulation target and the third on a remapped target. The coefficient of repeatability of the AI was 0.022 for intrasession and 0.040 for intersession assessments. For the optimal stimulation angle, the coefficients of repeatability were 3.7° and 5.1°, respectively. Both the AI and the optimal stimulation angle demonstrated good repeatability (Cronbach's ?>0.760). In conclusion, the results indicate that the AI can provide a reliable estimation of local functional anisotropy changes under conditions affecting the cortex, such as during stroke or focal dysplasia. PMID:26011386

  11. Fabrication of oriented antibody-conjugated magnetic nanoprobes and their immunoaffinity application.

    PubMed

    Lin, Po-Chiao; Chen, Shu-Hua; Wang, Kai-Yi; Chen, Mu-Lin; Adak, Avijit Kumar; Hwu, Jih-Ru R; Chen, Yu-Ju; Lin, Chun-Cheng

    2009-11-01

    In an attempt to fabricate highly active immunoprobes for serum biomarker detection, we report a simple and effective method for site-specific and self-oriented immobilization of antibodies on magnetic nanoparticles (MNPs). Through boronate formation, the carbohydrate moiety within the constant domain, Fc, of the antibody can be specifically and covalently linked to a boronic acid-functionalized MNP (BA@MNP) without hindering the antigen binding domain, Fab. The performance was evaluated by immunoaffinity extraction of multiple serum antigens. Compared with the random immobilization of antibody on a MNP, the antibody self-oriented immunoprobe provides long-term stability (>2 months) and 5-fold extraction efficiency. It also provides 5-fold improved sensitivity at a low nM range (0.4 nM), presumably through enhanced antibody@MNP activity. In addition, false-positive detections arising from nonspecific binding can be completely minimized by effective surface protection using concentration-dependent dextran blocking. Compared with conventional antibody site-specific immobilization through protein G, this new BA-mediated covalent antibody immobilization provides interference-free extraction resulting from noncovalent immobilization of antibody by protein G. The new immunoassay was applied in comparative profiling of serum amyloid P (SAP), serum amyloid A (SAA), and C-reactive protein (CRP) in human serum. Our triple immunoassay revealed a distinct pattern among normal patients, patients with cancer, and patients with cardiovascular disease. Using the previously reported quantization capability of the MALDI MS readout, we expect that this site-specific immunonanoprobe-based immunoassay can be highly active, rapid, and accurate in nanodiagnosis. PMID:19874051

  12. Highlights from the COMPASS Experiment

    SciTech Connect

    Bradamante, F. [Trieste University and INFN (Italy)

    2008-10-13

    An update is given of the ongoing experimental investigation of the spin structure of the nucleon carried on by the COMPASS Collaboration at CERN. Both longitudinal and transverse spin phenomena are covered. In the first case, the hot topic is the direct measurement of the gluon polarisation. Evidence is presented for {delta}G/G being small around x{sub g}{approx_equal}0.1, and its first moment should not be larger than 0.2-0.3 in absolute value. About transverse spin effects, evidence is given for new phenomena, associated with transverse momentum dependent distribution and fragmentation functions.

  13. Magnetism

    NSDL National Science Digital Library

    University Corporation for Atmospheric Research Windows to the Universe team

    2007-12-12

    This webpage is part of the University Corporation for Atmospheric Research (UCAR) Windows to the Universe program. It describes the nature and configuration of magnetic fields, which are the result of moving electric charges, including how they cause magnetic objects to orient themselves along the direction of the magnetic force points, which are illustrated as lines. Magnetic field lines by convention point outwards at the north magnetic pole and inward at the south magnetic pole. The site features text, scientific illustrations and an animation. Text and vocabulary are selectable for the beginning, intermediate, or advanced reader.

  14. The advanced stellar compass onboard the Oersted satellite

    NASA Technical Reports Server (NTRS)

    Jorgensen, John L.; Liebe, Carl Christian; Eisenman, Allan R.; Jensen, Gunnar B.

    1997-01-01

    The advanced stellar compass (ASC) star tracker installed onboard the Danish Oersted satellite designed to map the earth's magnetic vector field is presented. The ASC instrument will provide attitude data for the satellite and its payload. It consists of a CCD camera connected to a microcomputer, and operates by comparing star images from camera frames with its internal star catalogs. The instrument design is detailed, considering its key parameters, operating principles, and the different types of noise and error sources. A ground-based real sky evaluation and the calibration of the ASC are reported.

  15. Roe v. Wade. Reflective compassion.

    PubMed

    Padovano, A T

    1998-01-01

    The US has arrived at the correct legal status for induced abortion by permitting it on constitutional grounds within limits. In addition, the general consensus among American Catholics is in favor of abortion rights while disapproving of abortion and wishing to discourage it. Concerns about the morality of abortion, however, arise out of our uncertainty about the personhood of a fetus before birth or before viability. Early church leaders taught that a fetus did not obtain personhood until it acquired a human form, and the Catholic church did not baptize aborted fetuses without human shape or hold formal funeral services for dead fetuses. While official church teaching is adamant about the immorality of abortion, official church teaching has changed in the past in regard to the salvation of non-Catholics, slavery, inquisitions and torture, ecumenism, worship in the vernacular, and divorce and remarriage. No one is forced to have an abortion in the US because the legal right exists, and Catholics are more likely to heed Church teachings that do not seek legal force and punishment though "infallible" pronouncements and insensitive condemnation of women. If the Catholic church expects compassion for its wrong decisions in the past, then it should extend compassion to women in difficult situations. PMID:12178887

  16. Transverse spin effects at COMPASS

    SciTech Connect

    Pesaro, G. [Trieste University and INFN, via Valerio 2, 34148 Trieste (Italy)

    2009-03-23

    The COMPASS experiment at the CERN SPS has a broad physics program focused on the nucleon spin structure and on hadron spectroscopy, using both muon and hadron beams. One of the main objectives for the spin program with the muon beam is the measurement of transverse spin effects in semi inclusive deep inelastic scattering. A longitudinally polarized 160 GeV/c muon beam is impinging on a transversely polarized target: from 2002 to 2004 a {sup 6}LiD(deuteron) target has been used, while during 2007 data taking a NH{sub 3}(proton) target was put in place. All measured transverse asymmetries on deuteron have been found to be small, and compatible with zero, within the few percent statistical errors. These results, which are currently used as input for global fits, can be interpreted as cancellation between u and d quark contribution in the deuteron. The first results for the Collins and Sivers asymmetries for charged hadrons from the 2007 proton COMPASS data are also presented and discussed.

  17. The COMPASS Hadron Spectroscopy Programme

    E-print Network

    A. Austregesilo; for the COMPASS collaboration

    2012-07-05

    COMPASS is a fixed-target experiment at the CERN SPS for the investigation of the structure and the dynamics of hadrons. The experimental setup features a large acceptance and high momentum resolution spectrometer including particle identification and calorimetry and is therefore ideal to access a broad range of different final states. Following the promising observation of a spin-exotic resonance during an earlier pilot run, COMPASS focused on light-quark hadron spectroscopy during the years 2008 and 2009. A data set, world leading in terms of statistics and resolution, has been collected with a 190GeV/c hadron beam impinging on either liquid hydrogen or nuclear targets. Spin-exotic meson and glueball candidates formed in both diffractive dissociation and central production are presently studied. Since the beam composition includes protons, the excited baryon spectrum is also accessible. Furthermore, Primakoff reactions have the potential to determine radiative widths of the resonances and to probe chiral perturbation theory. An overview of the ongoing analyses will be presented. In particular, the employed partial wave analysis techniques will be illustrated and recent results will be shown for a selection of final states.

  18. Transverse Spin Effects at COMPASS

    E-print Network

    H. Wollny

    2009-02-03

    Single spin asymmetries in semi-inclusive deep-inelastic scattering off transversely polarized nucleon targets have been under intense experimental investigation over the past few years. They provide new insights into QCD and the nucleon structure. For instance, they allow the determination of the third yet-unknown leading-twist quark distribution function $\\Delta_{T}q(x)$, the transversity distribution. Additionally, they give insight into the parton transverse momentum distribution and angular momentum. The measurement of transverse spin effects in semi-inclusive deep-inelastic scattering is an important part of the COMPASS physics program. In the years 2002-2004 data were collected scattering a 160 GeV muon beam on a transversely polarized deuteron target. In 2007, additional data were collected on a transversely polarized proton target. New results from the analysis of the proton data will be presented. A different but not less important insight into the nucleon structure might be given by the Sivers asymmetry. This angular dependence of the cross-section arises from an intrinsic asymmetry in the parton transverse momentum distribution. The Sivers function is tightly related to the total angular momentum carried by the quarks in the nucleon. New COMPASS results for the Sivers asymmetry of the proton will be shown.

  19. Compassion fatigue, burnout, and compassion satisfaction among Colorado child protection workers

    Microsoft Academic Search

    David Conrad; Yvonne Kellar-Guenther

    2006-01-01

    ObjectiveThe goal of this study was to understand better the risk of compassion fatigue (the trauma suffered by the helping professional) and burnout (emotional exhaustion, depersonalization, and reduced sense of personal accomplishment), and the potential for compassion satisfaction (the fulfillment from helping others and positive collegial relationships) among Colorado county child protection staff using the Compassion Satisfaction\\/Fatigue Self-Test [Figley, C.

  20. Growth and magnetism of highly (001)-oriented [Fe/Pt]n/Pt films

    NASA Astrophysics Data System (ADS)

    George, T. A.; Li, X. Z.; Yue, L.; Sellmyer, David J.

    2011-03-01

    Highly (001) textured non-epitaxial L 1 0 FePt films have been fabricated on Si O2 substrates by post-deposition annealing 11 nm magnetron sputtered multilayers of Fe and Pt with an additional overlayer of 1 nm Pt. An identical series of films was made without the thick Pt terminating layer for comparison. All films were post-deposition annealed at 600 °C for 300 s in a rapid thermal processor and show a high degree of chemical order. The ordered films without a Pt overlayer include a mixture of (001) and randomly oriented grains. In the samples with a Pt overlayer only the (00 l) peaks are visible, demonstrating an enormous enhancement in the degree of (001) texture. Structural analysis reveals a decrease in surface roughness from over 2 nm to less than 1 nm, elimination of voided regions, and an increase in average grain size from 50 to 150 nm with the inclusion of a Pt overlayer. Magnetic hysteresis loops show a high squareness ratio for Pt-overlayer samples with coercivities much smaller than their no-overlayer counterparts. The effects of Fe:Pt stoichiometry and bilayer thickness are investigated along with the involved grain-growth process. This research is supported by NSF-MRSEC, DOE, and NCMN.

  1. Magnetic moment of {sup 104}Ag{sup m} and the hyperfine magnetic field of Ag in Fe using nuclear magnetic resonance on oriented nuclei

    SciTech Connect

    Golovko, V. V.; Kraev, I. S.; Phalet, T.; Delaure, B.; Beck, M.; Kozlov, V. Yu.; Coeck, S.; Wauters, F.; Severijns, N. [Instituut voor Kern-en Stralingsfysica, Katholieke Universiteit Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Herzog, P.; Tramm, Ch. [Helmholtz-Institut fuer Strahlen- und Kernphysik, Universitaet Bonn, D-53115 Bonn (Germany); Zakoucky, D.; Venos, D.; Srnka, D.; Honusek, M. [Nuclear Physics Institute, ASCR, CZ-250 68 Rez (Czech Republic); Koester, U. [Institut Laue Langevin, 6 rue Jules Horowitz, F-38042 Grenoble Cedex 9 (France); ISOLDE, CERN, CH-1211 Geneve 23 (Switzerland)

    2010-05-15

    Nuclear magnetic resonance (NMR/ON) measurements with beta- and gamma-ray detection have been performed on oriented {sup 104}Ag{sup g,m} nuclei with the NICOLE {sup 3}He-{sup 4}He dilution refrigerator setup at ISOLDE/CERN. For {sup 104}Ag{sup g} (I{sup p}i=5{sup +}) the gamma-NMR/ON resonance signal was found at nu=266.70(5) MHz. Combining this result with the known magnetic moment for this isotope, the magnetic hyperfine field of Ag impurities in an Fe host at low temperature (<1 K) is found to be |B{sub hf}(AgFe)|=44.709(35) T. A detailed analysis of other relevant data available in the literature yields three more values for this hyperfine field. Averaging all four values yields a new and precise value for the hyperfine field of Ag in Fe; that is, |B{sub hf}(AgFe)|=44.692(30) T. For {sup 104}Ag{sup m} (I{sup p}i=2{sup +}), the anisotropy of the beta particles provided the NMR/ON resonance signal at nu=627.7(4) MHz. Using the new value for the hyperfine field of Ag in Fe, this frequency corresponds to the magnetic moment mu({sup 104m}Ag)=+3.691(3) mu{sub N}, which is significantly more precise than previous results. The magnetic moments of the even-A {sup 102-110}Ag isotopes are discussed in view of the competition between the (pig{sub 9/2}){sub 7/2}{sup +-3}(nud{sub 5/2}nug{sub 7/2}){sub 5/2}{sup +} and the (pig{sub 9/2}){sub 9/2}{sup +-3}(nud{sub 5/2}nug{sub 7/2}){sub 5/2}{sup +} configurations. The magnetic moments of the ground and isomeric states of {sup 104}Ag can be explained by an almost complete mixing of these two configurations.

  2. Orientation within a high magnetic field determines swimming direction and laterality of c-Fos induction in mice

    PubMed Central

    Kwon, Bumsup; Houpt, Charles E.; Neth, Bryan; Smith, James C.

    2013-01-01

    High-strength static magnetic fields (>7 tesla) perturb the vestibular system causing dizziness, nystagmus, and nausea in humans; and head motion, locomotor circling, conditioned taste aversion, and c-Fos induction in brain stem vestibular nuclei in rodents. To determine the role of head orientation, mice were exposed for 15 min within a 14.1-tesla magnet at six different angles (mice oriented parallel to the field with the head toward B+ at 0°; or pitched rostrally down at 45°, 90°, 90° sideways, 135°, and 180°), followed by a 2-min swimming test. Additional mice were exposed at 0°, 90°, and 180° and processed for c-Fos immunohistochemistry. Magnetic field exposure induced circular swimming that was maximal at 0° and 180° but attenuated at 45° and 135°. Mice exposed at 0° and 45° swam counterclockwise, whereas mice exposed at 135° and 180° swam clockwise. Mice exposed at 90° (with their rostral-caudal axis perpendicular to the magnetic field) did not swim differently than controls. In parallel, exposure at 0° and 180° induced c-Fos in vestibular nuclei with left-right asymmetries that were reversed at 0° vs. 180°. No significant c-Fos was induced after 90° exposure. Thus, the optimal orientation for magnetic field effects is the rostral-caudal axis parallel to the field, such that the horizontal canal and utricle are also parallel to the field. These results have mechanistic implications for modeling magnetic field interactions with the vestibular apparatus of the inner ear (e.g., the model of Roberts et al. of an induced Lorenz force causing horizontal canal cupula deflection). PMID:23720133

  3. Orientation of superconducting crystalline MgB(sub 2) in magnetic field determined by x-ray diffraction.

    SciTech Connect

    Li, J.; Vaknin, D.; Bud'ko, S.; Canfield, P. C.; Pal, D.; Eskildsen, M. R.; Islam, Z.; Kogan, V. G.; Iowa State; Univ. of Notre Dame

    2006-01-01

    It is well established experimentally and theoretically that MgB{sub 2} exhibits unique and intriguing anisotropic properties. These are manifested in the ratios of the upper critical fields {gamma}{sub H} = H{sub c2}, {sup ab}/H{sub cw}{sup c} and of the London penetration depth {gamma}{sub {lambda}} = {lambda}{sub c}/{lambda}{sub ab}. Experimental evidence shows that {gamma}{sub H} = {gamma}{sub {lambda}} {approx} 2 near T{sub c}, and at low temperatures {gamma}{sub {lambda}} {approx} 1 and {gamma}{sub H} {approx} 6. For a crystal with {gamma}{sub H} = {gamma}{sub {lambda}} in a field along the c-axis, superconducting free single crystal grains experience a torque that tends to orient their ab plane parallel to the field. However, for {gamma}{sub {lambda}} {ne} {gamma}{sub H}, recent theoretical predictions suggest that a crystal will orient with its c-axis along the magnetic field. Thus, the temperature dependencies of {gamma}{sub {lambda}} and {gamma}{sub H} suggest that near T{sub c}, where {gamma}{sub H} = {gamma}{sub {lambda}} an MgB{sub 2} crystal will orient with its ab-axis parallel to magnetic field, and at low temperatures where {gamma}{sub {lambda}} {ne} {gamma}{sub H} it will orient with its c-axis along the field. Herein, we present synchrotron X-ray diffraction studies to determine the preferred orientation of crystalline powdered samples under applied magnetic fields at various temperatures.

  4. Magnetic monitoring of earth and space

    USGS Publications Warehouse

    Love, J.J.

    2008-01-01

    For centuries, navigators of the world's oceans have been familiar with an effect of Earth's magnetic field: It imparts a directional preference to the needle of a compass. Although in some settings magnetic orientation remains important, the modern science of geomagnetism has emerged from its romantic nautical origins and developed into a subject of great depth and diversity. The geomagnetic field is used to explore the dynamics of Earth's interior and its surrounding space environment, and geomagnetic data are used for geophysical mapping, mineral exploration, risk mitigation, and other practical applications. A global distribution of ground-based magnetic observatories supports those pursuits by providing accurate records of the magnetic-field direction and intensity at fixed locations and over long periods of time.

  5. Domain wall assisted magnetization switching in (111) oriented L1{sub 0} FePt grown on a soft magnetic metallic glass

    SciTech Connect

    Kaushik, Neelam [World Premier Initiative (WPI) Center, Advanced Institute for Materials Research (AIMR), Tohoku University, Sendai 980-8577 (Japan); Sharma, Parmanand; Yubuta, Kunio; Makino, Akihiro [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Inoue, Akihisa [Tohoku University, Sendai 980-8577 (Japan)

    2010-08-16

    We report on growth and magnetic properties of exchange-coupled (111)-L1{sub 0} FePt hard/CoFeTaB soft magnetic metallic glass bilayered structure processed at lower temperature ({approx}400 deg. C). Single phaselike hysteresis loops with tailorable coercivity (<8.2 kOe) in out of plane direction are obtained. The magnetization switching mechanism is identified as domain wall assisted. In views of excellent nanofabrication abilities of metallic glass thin film and the ability to grow preferred oriented L1{sub 0} FePt, the present bilayered structure is very promising for the fabrication of high density bit--patterned magnetic recording media and other spintronic devices.

  6. The polarization trajectory of terahertz magnetic dipole radiation in (110)-oriented PrFeO{sub 3} single crystal

    SciTech Connect

    Song, Gaibei; Jin, Zuanming; Lin, Xian; Jiang, Junjie; Wang, Xinyan; Wu, Hailong; Ma, Guohong, E-mail: ghma@staff.shu.edu.cn, E-mail: sxcao@shu.edu.cn; Cao, Shixun, E-mail: ghma@staff.shu.edu.cn, E-mail: sxcao@shu.edu.cn [Department of Physics, Shanghai University, Shanghai 200444 (China)

    2014-04-28

    By using the polarized terahertz (THz) time-domain spectroscopy, the macro-magnetization motion in (110)-oriented PrFeO{sub 3} single crystal was constructed. We emphasize that the trajectory of the emitted THz waveforms relies on not only the motion of macroscopic magnetization vector, but also the spin configuration in the ground state and the propagation of THz pulse. The azimuthal angle (the incident THz pulse polarization with respect to the crystal axes) enables us to control the polarization trajectories of the quasiferromagnetic and quasiantiferromagnetic mode radiations that can lead to further applications on multiple information storing and quantum processing.

  7. Compassion fatigue within nursing practice: a concept analysis.

    PubMed

    Coetzee, Siedine Knobloch; Klopper, Hester C

    2010-06-01

    "Compassion fatigue" was first introduced in relation to the study of burnout among nurses, but it was never defined within this context; it has since been adopted as a synonym for secondary traumatic stress disorder, which is far removed from the original meaning of the term. The aim of the study was to define compassion fatigue within nursing practice. The method that was used in this article was concept analysis. The findings revealed several categories of compassion fatigue: risk factors, causes, process, and manifestations. The characteristics of each of these categories are specified and a connotative (theoretical) definition, model case, additional cases, empirical indicators, and a denotative (operational) definition are provided. Compassion fatigue progresses from a state of compassion discomfort to compassion stress and, finally, to compassion fatigue, which if not effaced in its early stages of compassion discomfort or compassion stress, can permanently alter the compassionate ability of the nurse. Recommendations for nursing practice, education, and research are discussed. PMID:20602697

  8. Effects of magnetic field orientation on optical decoherence in Er3+:Y2SiO5

    Microsoft Academic Search

    Thomas Böttger; C. W. Thiel; R. L. Cone; Y. Sun

    2009-01-01

    The influence of the anisotropic Zeeman effect on optical decoherence was studied for the 1.54mum telecom transition in Er3+:Y2SiO5 using photon echo spectroscopy as a function of applied magnetic field orientation and strength. The decoherence strongly correlates with the Zeeman energy splittings described by the ground- and excited-state g factor variations for all inequivalent Er3+ sites, with the observed decoherence

  9. Design and Implementation of Simple Field-Oriented Control for Permanent Magnet Stepper Motors Without DQ Transformation

    Microsoft Academic Search

    Wonhee Kim; Chuan Yang; Chung Choo Chung

    2011-01-01

    In this paper, a simple field-oriented control (FOC) without direct quadrature (DQ) transformation is proposed for position tracking of permanent magnet stepper motors (PMSMs). Conventional FOC methods require DQ transformation to linearize the mechanical dynamics for PMSMs. In this paper, a proportional-integral-derivative controller with velocity feedforward is developed to obtain the torque modulation required to track the desired position. In

  10. Conformation of Alamethicin in Oriented Phospholipid Bilayers Determined by 15N Solid-State Nuclear Magnetic Resonance

    Microsoft Academic Search

    Mads Bak; Robert P. Bywater; Morten Hohwy; Jens K. Thomsen; Kim Adelhorst; Hans J. Jakobsen; Ole W. Sørensen; Niels C. Nielsen

    2001-01-01

    The conformation of the 20-residue antibiotic ionophore alamethicin in macroscopically oriented phospholipid bilayers has been studied using 15N solid-state nuclear magnetic resonance (NMR) spectroscopy in combination with molecular modeling and molecular dynamics simulations. Differently 15N-labeled variants of alamethicin and an analog with three of the ?-amino-isobutyric acid residues replaced by alanines have been investigated to establish experimental structural constraints and

  11. INNOVATION FEATURES OF BUILDING OF MAGNETIC-GRAVITATIONAL SUBSYSTEM OF SYSTEM OF DETERMINATION AND ORIENTATION CONTROL FOR MICROSATELLITE PLATFORM

    Microsoft Academic Search

    Sergey V. Ostapchuk; Victor S. Khoroshilov

    The self-passive magnetic-gravitational sub-system of satellite calming including orientation and stabilization was considered for 25kg microsatellite MS-'Ex'. According to given requirements the composition of attitude control sub-system (ACS) was determined. Mathematical model and software programme in MatLab for simulation of the microsatellite dynamics relatively of the microsatellite center of masses were developed. The calculation results were presented and ways of

  12. Pulsed nuclear magnetic resonance of oriented nuclei in an insulating magnetic material: 54 Mn?MnCl 2 .4H 2 O

    Microsoft Academic Search

    M. Le Gros; A. Kotlicki; B. G. Turrell

    1987-01-01

    The first observation of pulsed nuclear magnetic resonance of oriented nuclei in an insulating magnetic material is reported.\\u000a The system studied was the ordered antiferromagnet54Mn?MnCl2.4H2O. The response of the54Mn spins to a single pulse of variable length, the free induction decay, and Hahn spin-echo have all been observed. A discussion\\u000a of the transverse decoherent relaxation timeT\\u000a 2 in MnCl2.4H2O is

  13. Seed orientation and magnetic field strength have more influence on tomato seed performance than relative humidity and duration of exposure to non-uniform static magnetic fields.

    PubMed

    Poinapen, Danny; Brown, Daniel C W; Beeharry, Girish K

    2013-09-15

    Different factors (e.g., light, humidity, and temperature) including exposure to static magnetic fields (SMFs), referred here as critical factors, can significantly affect horticultural seed performance. However, the link between magnetic field parameters and other interdependent factors affecting seed viability is unclear. The importance of these critical factors affecting tomato (Solanum lycopersicum L.) var. MST/32 seed performance was assessed after performing several treatments based on a L9 (3(4)) (four factors at three levels) orthogonal array (OA) design. The variable factors in the design were magnetic flux density (R1=332.1±37.8mT; R2=108.7±26.9mT; and R3=50.6±10.5mT), exposure time (1, 2, and 24h), seed orientation (North polarity, South polarity, and control - no magnetic field), and relative humidity (RH) (7.0, 25.5, and 75.5%). After seed moisture content stabilisation at the different chosen RH, seeds were exposed in dark under laboratory conditions to several treatments based on the OA design before performance evaluation. Treatments not employing magnetic field exposure were used as controls. Results indicate that electrolyte leakage rate was reduced by a factor of 1.62 times during seed imbibition when non-uniform SMFs were employed. Higher germination (?11.0%) was observed in magnetically-exposed seeds than in non-exposed ones, although seedlings emerging from SMF treatments did not show a consistent increase in biomass accumulation. The respective influence of the four critical factors tested on seed performance was ranked (in decreasing order) as seed orientation to external magnetic fields, magnetic field strength, RH, and exposure time. This study suggests a significant effect of non-uniform SMFs on seed performance with respect to RH, and more pronounced effects are observed during seed imbibition rather than during later developmental stages. PMID:23759543

  14. Recognising and combating compassion fatigue in nursing.

    PubMed

    Mendes, Aysha

    In this monthly column, Aysha Mendes explores the reasons why nurses may feel compassion fatigue and ways NHS organisations and nurses themselves can engage in activities that will help them renew their emotional energy. PMID:25426529

  15. Video Compass Jana Kosecka and Wei Zhang

    E-print Network

    Kosecka, Jana

    Video Compass Jana Koseck´a and Wei Zhang Department of Computer Science, George Mason University in building large city models as well as basic surveillance and monitoring applications often encounter

  16. Honeybee navigation: critically examining the role of the polarization compass

    PubMed Central

    Evangelista, C.; Kraft, P.; Dacke, M.; Labhart, T.; Srinivasan, M. V.

    2014-01-01

    Although it is widely accepted that honeybees use the polarized-light pattern of the sky as a compass for navigation, there is little direct evidence that this information is actually sensed during flight. Here, we ask whether flying bees can obtain compass cues derived purely from polarized light, and communicate this information to their nest-mates through the ‘waggle dance’. Bees, from an observation hive with vertically oriented honeycombs, were trained to fly to a food source at the end of a tunnel, which provided overhead illumination that was polarized either parallel to the axis of the tunnel, or perpendicular to it. When the illumination was transversely polarized, bees danced in a predominantly vertical direction with waggles occurring equally frequently in the upward or the downward direction. They were thus using the polarized-light information to signal the two possible directions in which they could have flown in natural outdoor flight: either directly towards the sun, or directly away from it. When the illumination was axially polarized, the bees danced in a predominantly horizontal direction with waggles directed either to the left or the right, indicating that they could have flown in an azimuthal direction that was 90° to the right or to the left of the sun, respectively. When the first half of the tunnel provided axial illumination and the second half transverse illumination, bees danced along all of the four principal diagonal directions, which represent four equally likely locations of the food source based on the polarized-light information that they had acquired during their journey. We conclude that flying bees are capable of obtaining and signalling compass information that is derived purely from polarized light. Furthermore, they deal with the directional ambiguity that is inherent in polarized light by signalling all of the possible locations of the food source in their dances, thus maximizing the chances of recruitment to it. PMID:24395964

  17. Honeybee navigation: critically examining the role of the polarization compass.

    PubMed

    Evangelista, C; Kraft, P; Dacke, M; Labhart, T; Srinivasan, M V

    2014-01-01

    Although it is widely accepted that honeybees use the polarized-light pattern of the sky as a compass for navigation, there is little direct evidence that this information is actually sensed during flight. Here, we ask whether flying bees can obtain compass cues derived purely from polarized light, and communicate this information to their nest-mates through the 'waggle dance'. Bees, from an observation hive with vertically oriented honeycombs, were trained to fly to a food source at the end of a tunnel, which provided overhead illumination that was polarized either parallel to the axis of the tunnel, or perpendicular to it. When the illumination was transversely polarized, bees danced in a predominantly vertical direction with waggles occurring equally frequently in the upward or the downward direction. They were thus using the polarized-light information to signal the two possible directions in which they could have flown in natural outdoor flight: either directly towards the sun, or directly away from it. When the illumination was axially polarized, the bees danced in a predominantly horizontal direction with waggles directed either to the left or the right, indicating that they could have flown in an azimuthal direction that was 90° to the right or to the left of the sun, respectively. When the first half of the tunnel provided axial illumination and the second half transverse illumination, bees danced along all of the four principal diagonal directions, which represent four equally likely locations of the food source based on the polarized-light information that they had acquired during their journey. We conclude that flying bees are capable of obtaining and signalling compass information that is derived purely from polarized light. Furthermore, they deal with the directional ambiguity that is inherent in polarized light by signalling all of the possible locations of the food source in their dances, thus maximizing the chances of recruitment to it. PMID:24395964

  18. Study of the Influence of the Orientation of a 50-Hz Magnetic Field on Fetal Exposure Using Polynomial Chaos Decomposition

    PubMed Central

    Liorni, Ilaria; Parazzini, Marta; Fiocchi, Serena; Ravazzani, Paolo

    2015-01-01

    Human exposure modelling is a complex topic, because in a realistic exposure scenario, several parameters (e.g., the source, the orientation of incident fields, the morphology of subjects) vary and influence the dose. Deterministic dosimetry, so far used to analyze human exposure to electromagnetic fields (EMF), is highly time consuming if the previously-mentioned variations are considered. Stochastic dosimetry is an alternative method to build analytical approximations of exposure at a lower computational cost. In this study, it was used to assess the influence of magnetic flux density (B) orientation on fetal exposure at 50 Hz by polynomial chaos (PC). A PC expansion of induced electric field (E) in each fetal tissue at different gestational ages (GA) was built as a function of B orientation. Maximum E in each fetal tissue and at each GA was estimated for different exposure configurations and compared with the limits of the International Commission of Non-Ionising Radiation Protection (ICNIRP) Guidelines 2010. PC theory resulted in an efficient tool to build accurate approximations of E in each fetal tissue. B orientation strongly influenced E, with a variability across tissues from 10% to 43% with respect to the mean value. However, varying B orientation, maximum E in each fetal tissue was below the limits of ICNIRP 2010 at all GAs. PMID:26024363

  19. Study of the influence of the orientation of a 50-Hz magnetic field on fetal exposure using polynomial chaos decomposition.

    PubMed

    Liorni, Ilaria; Parazzini, Marta; Fiocchi, Serena; Ravazzani, Paolo

    2015-01-01

    Human exposure modelling is a complex topic, because in a realistic exposure scenario, several parameters (e.g., the source, the orientation of incident fields, the morphology of subjects) vary and influence the dose. Deterministic dosimetry, so far used to analyze human exposure to electromagnetic fields (EMF), is highly time consuming if the previously-mentioned variations are considered. Stochastic dosimetry is an alternative method to build analytical approximations of exposure at a lower computational cost. In this study, it was used to assess the influence of magnetic flux density (B) orientation on fetal exposure at 50 Hz by polynomial chaos (PC). A PC expansion of induced electric field (E) in each fetal tissue at different gestational ages (GA) was built as a function of B orientation. Maximum E in each fetal tissue and at each GA was estimated for different exposure configurations and compared with the limits of the International Commission of Non-Ionising Radiation Protection (ICNIRP) Guidelines 2010. PC theory resulted in an efficient tool to build accurate approximations of E in each fetal tissue. B orientation strongly influenced E, with a variability across tissues from 10% to 43% with respect to the mean value. However, varying B orientation, maximum E in each fetal tissue was below the limits of ICNIRP 2010 at all GAs. PMID:26024363

  20. The origins of the Carolinian sidereal compass 

    E-print Network

    Halpern, Michael David

    1985-01-01

    -INSTRUMENTAL SIDEREAL NAVIGATION CHAPTER III. THEORY AND METHOD CHAPTER IV. ASTRONOMICAL EVALUATION CHAPTER VS ARCHAEOLOGY, ETHNOGRAPHY& AND HISTORY CHAPTER VZ. SUMMARY ANALYSIS AND CONCLUSIONS REFERENCES CITED . . . . . . . . . . . . . . ~ . ~ Supplemental... of knowledge of the various compasses described. A theoretical framework for the evaluation of diffusionist. versus inventionist arguments is developed and a set of criteria is presented. The Carolinian and Arab compasses are analyzed from a temporo-astronomical...

  1. Deterministic learning based compass biped robot control

    Microsoft Academic Search

    Xue Zhengui; Wang Cong

    2008-01-01

    In this paper, based on a resent result of deterministic learning, we present an approach for the compass gait biped control and learning. When a compass-like robot is controlled to perform a desired walking pattern, locally-accurate approximation of the closed-loop control system dynamics can be achieved in a local region along the periodic gait. Moreover, like the learning process of

  2. The compass rose andrand om walk tests

    Microsoft Academic Search

    Yue Fang

    2002-01-01

    The recent discovery of the compass rose pattern (Crack and Ledoit J. Finance 51(2) (1996) 751) has sparkedconsid erable interest among researchers. This paper explores the signi1cance of the e2ect of the compass rose pattern on random walk tests and measures to what extent its in3uence may limit the performance of test statistics. We show that in general, the asymptotic

  3. Self-compassion and PTSD symptom severity

    Microsoft Academic Search

    Brian L. Thompson; Jennifer Waltz

    2008-01-01

    Neff 's (2003a, 2003b) notion of self-compassion emphasizes kindness towards one's self, a feeling of connectedness with others, and mindful awareness of distressing experiences. Because exposure to trauma and subsequent posttraumatic stress symptoms (PSS) may be associated with self-criticism and avoidance of internal experiences, the authors examined the relationship between self-compassion and PSS. Out of a sample of 210 university

  4. Contradictory results on the role of polarized light in compass calibration in migratory songbirds

    Microsoft Academic Search

    Roswitha Wiltschko; Ursula Munro; Hugh Ford; Wolfgang Wiltschko

    2008-01-01

    Experiments with migrating birds on the interaction between magnetic and celestial cues have produced heterogeneous results.\\u000a A recent study claimed that the magnetic compass in passerine migrants is calibrated by the pattern of polarized light at\\u000a sunset and sunrise and that the area just above the horizon is crucial for this calibration. To test the latter hypothesis,\\u000a we performed a

  5. 18. Semm, P., Nohr, D., Demaine, C. & Wiltschko, W. Neural basis of the magnetic compass: interaction of visual, magnetic and vestibular inputs in the pigeon's brain. J. Comp. Physiol. A 155, 283288 (1984).

    E-print Network

    Zhang, Li I.

    1984-01-01

    : interaction of visual, magnetic and vestibular inputs in the pigeon's brain. J. Comp. Physiol. A 155, 283 projection from the nucleus of the basal optic root to the nucleus rotundus in pigeons. Neurosci. Lett. 305

  6. Connecting the navigational clock to sun compass input in monarch butterfly brain.

    PubMed

    Sauman, Ivo; Briscoe, Adriana D; Zhu, Haisun; Shi, Dingding; Froy, Oren; Stalleicken, Julia; Yuan, Quan; Casselman, Amy; Reppert, Steven M

    2005-05-01

    Migratory monarch butterflies (Danaus plexippus) use a time-compensated sun compass to navigate to their overwintering grounds in Mexico. Although polarized light is one of the celestial cues used for orientation, the spectral content (color) of that light has not been fully explored. We cloned the cDNAs of three visual pigment-encoding opsins (ultraviolet [UV], blue, and long wavelength) and found that all three are expressed uniformly in main retina. The photoreceptors of the polarization-specialized dorsal rim area, on the other hand, are monochromatic for the UV opsin. Behavioral studies support the importance of polarized UV light for flight orientation. Next, we used clock protein expression patterns to identify the location of a circadian clock in the dorsolateral protocerebrum of butterfly brain. To provide a link between the clock and the sun compass, we identified a CRYPTOCHROME-staining neural pathway that likely connects the circadian clock to polarized light input entering brain. PMID:15882645

  7. The COMPASS Experiment at CERN

    E-print Network

    Abbon, P.; Alexakhin, V.Yu.; Alexandrov, Yu.; Alexeev, G.D.; Alekseev, M.G.; Amoroso, A.; Angerer, H.; Anosov, V.A.; Badelek, B.; Balestra, F.; Ball, J.; Barth, J.; Baum, G.; Becker, M.; Bedfer, Y.; Berglund, P.; Bernet, C.; Bertini, R.; Bettinelli, M.; Birsa, R.; Bisplinghoff, J.; Bordalo, P.; Bosteels, M.; Bradamante, F.; Braem, A.; Bravar, A.; Bressan, A.; Brona, G.; Burtin, E.; Bussa, M.P.; Bytchkov, V.N.; Chalifour, M.; Chapiro, A.; Chiosso, M.; Ciliberti, P.; Cicuttin, A.; Colantoni, M.; Colavita, A.A.; Costa, S.; Crespo, M.L.; Cristaudo, P.; Dafni, T.; d'Hose, N.; Dalla Torre, S.; d'Ambrosio, C.; Das, S.; Dasgupta, S.S.; Delagnes, E.; De Masi, R.; Deck, P.; Dedek, N.; Demchenko, D.; Denisov, O.Yu.; Dhara, L.; Diaz, V.; Dibiase, N.; Dinkelbach, A.M.; Dolgopolov, A.V.; Donati, A.; Donskov, S.V.; Dorofeev, V.A.; Doshita, N.; Durand, D.; Duic, V.; Dunnweber, W.; Efremov, A.; Eversheim, P.D.; Eyrich, W.; Faessler, M.; Falaleev, V.; Fauland, P.; Ferrero, A.; Ferrero, L.; Finger, M.; Finger, M.; Fischer, H.; Franco, C.; Franz, J.; Fratnik, F.; Friedrich, J.M.; Frolov, V.; Fuchs, U.; Garfagnini, R.; Gatignon, L.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Geyer, R.; Gheller, J.M.; Giganon, A.; Giorgi, M.; Gobbo, B.; Goertz, S.; Gorin, A.M.; Gougnaud, F.; Grabmuller, S.; Grajek, O.A.; Grasso, A.; Grube, B.; Grunemaier, A.; Guskov, A.; Haas, F.; Hagemann, R.; Hannappel, J.; von Harrach, D.; Hasegawa, T.; Heckmann, J.; Hedicke, S.; Heinsius, F.H.; Hermann, R.; Hess, C.; Hinterberger, F.; von Hodenberg, M.; Horikawa, N.; Horikawa, S.; Horn, I.; Ilgner, C.; Ioukaev, A.I.; Ishimoto, S.; Ivanchin, I.; Ivanov, O.; Iwata, T.; Jahn, R.; Janata, A.; Joosten, R.; Jouravlev, N.I.; Kabuss, E.; Kalinnikov, V.; Kang, D.; Karstens, F.; Kastaun, W.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu.A.; Kiefer, J.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koblitz, S.; Koivuniemi, J.H.; Kolosov, V.N.; Komissarov, E.V.; Kondo, K.; Konigsmann, Kay; Konoplyannikov, A.K.; Konorov, I.; Konstantinov, V.F.; Korentchenko, A.S.; Korzenev, A.; Kotzinian, A.M.; Koutchinski, N.A.; Kouznetsov, O.; Kowalik, K.; Kramer, D.; Kravchuk, N.P.; Krivokhizhin, G.V.; Kroumchtein, Z.V.; Kubart, J.; Kuhn, R.; Kukhtin, V.; Kunne, F.; Kurek, K.; Kuzmin, N.A.; Lamanna, M.; Le Goff, J.M.; Leberig, M.; Lednev, A.A.; Lehmann, A.; Levinski, V.; Levorato, S.; Lyashenko, V.I; Lichtenstadt, J.; Liska, T.; Ludwig, I.; Maggiora, A.; Maggiora, M.; Magnon, A.; Mallot, G.K.; Mann, A.; Manuilov, I.V.; Marchand, C.; Marroncle, J.; Martin, A.; Marzec, J.; Masek, L.; Massmann, F.; Matsuda, T.; Matthia, D.; Maximov, A.N.; Menon, G.; Meyer, W.; Mielech, A.; Mikhailov, Yu.V.; Moinester, M.A.; Molinie, F.; Mota, F.; Mutter, A.; Nagel, T.; Nahle, O.; Nassalski, J.; Neliba, S.; Nerling, F.; Neyret, D.; Niebuhr, M.; Niinikoski, T.; Nikolaenko, V.I.; Nozdrin, A.A.; Olshevsky, A.G.; Ostrick, M.; Padee, A.; Pagano, P.; Panebianco, S.; Parsamyan, B.; Panzieri, D.; Paul, S.; Pawlukiewicz, B.; Pereira, H.; Peshekhonov, D.V.; Peshekhonov, V.D.; Piedigrossi, D.; Piragino, G.; Platchkov, S.; Platzer, K.; Pochodzalla, J.; Polak, J.; Polyakov, V.A.; Pontecorvo, G.; Popov, A.A.; Pretz, J.; Procureur, S.; Quintans, C.; Rajotte, J.-F.; Ramos, S.; Razaq, I.; Rebourgeard, P.; Reggiani, D.; Reicherz, G.; Richter, A.; Robinet, F.; Rocco, E.; Rondio, E.; Ropelewski, L.; Rousse, J.Y.; Rozhdestvensky, A.M.; Ryabchikov, D.; Samartsev, A.G.; Samoylenko, V.D.; Sandacz, A.; Merce, M.Sans; Santos, H.; Sapozhnikov, M.G.; Sauli, F.; Savin, Igor A.; Schiavon, P.; Schill, C.; Schmidt, T.; Schmitt, H.; Schmitt, L.; Schonmeier, P.; Schroeder, W.; Seeharsch, D.; Seimetz, M.; Setter, D.; Shaligin, A.; Shevchenko, O.Yu.; Shishkin, A.A.; Siebert, H.-W.; Silva, L.; Simon, F.; Sinha, L.; Sissakian, A.N.; Slunecka, M.; Smirnov, G.I.; Sora, D.; Sosio, S.; Sozzi, F.; Srnka, A.; Stinzing, F.; Stolarski, M.; Sugonyaev, V.P.; Sulc, M.; Sulej, R.; Tarte, G.; Takabayashi, N.; Tchalishev, V.V.; Tessaro, S.; Tessarotto, F.; Teufel, A.; Thers, D.; Tkatchev, L.G.; Toeda, T.; Tokmenin, V.V.; Trippel, S.; Urban, J.; Valbuena, R.; Venugopal, G.; Virius, M.; Vlassov, N.V.; Vossen, A.; Wagner, M.; Webb, R.; Weise, E.; Weitzel, Q.; Wiedner, U.; Wiesmann, M.; Windmolders, R.; Wirth, S.; Wislicki, W.; Wollny, H.; Zanetti, A.M.; Zaremba, K.; Zavertyaev, M.; Zhao, J.; Ziegler, R.; Ziembicki, M.; Zlobin, Y.L.; Zvyagin, A.

    2007-01-01

    The COMPASS experiment makes use of the CERN SPS high-intensitymuon and hadron beams for the investigation of the nucleon spin structure and the spectroscopy of hadrons. One or more outgoing particles are detected in coincidence with the incoming muon or hadron. A large polarized target inside a superconducting solenoid is used for the measurements with the muon beam. Outgoing particles are detected by a two-stage, large angle and large momentum range spectrometer. The setup is built using several types of tracking detectors, according to the expected incident rate, required space resolution and the solid angle to be covered. Particle identification is achieved using a RICH counter and both hadron and electromagnetic calorimeters. The setup has been successfully operated from 2002 onwards using a muon beam. Data with a hadron beam were also collected in 2004. This article describes the main features and performances of the spectrometer in 2004; a short summary of the 2006 upgrade is also given.

  8. The Compass Experiment at CERN

    SciTech Connect

    Magnon, A. [DAPNIA/SPhN, CEA-Saclay, F91191 Gif-Sur-Yvette Cedex (France)

    2005-02-10

    The COMPASS experiment at the CERN SPS has a broad physics program focused on the study of the spin structure of the nucleon and on hadron spectroscopy. Key measurements for the spin program are the gluon contribution to the spin of the nucleon, flavor dependent quark spin distribution, and the measurement of the transverse spin structure function. The apparatus consists of a two-stage spectrometer designed for high data rates and equipped with high-resolution tracking, particle identification, electromagnetic and hadronic calorimetry. Data taking has started in 2002. Following the CERN SPS shut down in 2005, the experiment will resume data taking in 2006 and is planned to continue (at least) until 2010. Few hundreds of Terabytes of data are put on tape each year. Out of this large amount of data first important physics results have been obtained.

  9. The COMPASS experiment at CERN

    NASA Astrophysics Data System (ADS)

    Abbon, P.; Albrecht, E.; Alexakhin, V. Yu.; Alexandrov, Yu.; Alexeev, G. D.; Alekseev, M. G.; Amoroso, A.; Angerer, H.; Anosov, V. A.; Bade?ek, B.; Balestra, F.; Ball, J.; Barth, J.; Baum, G.; Becker, M.; Bedfer, Y.; Berglund, P.; Bernet, C.; Bertini, R.; Bettinelli, M.; Birsa, R.; Bisplinghoff, J.; Bordalo, P.; Bosteels, M.; Bradamante, F.; Braem, A.; Bravar, A.; Bressan, A.; Brona, G.; Burtin, E.; Bussa, M. P.; Bytchkov, V. N.; Chalifour, M.; Chapiro, A.; Chiosso, M.; Ciliberti, P.; Cicuttin, A.; Colantoni, M.; Colavita, A. A.; Costa, S.; Crespo, M. L.; Cristaudo, P.; Dafni, T.; d'Hose, N.; Dalla Torre, S.; d'Ambrosio, C.; Das, S.; Dasgupta, S. S.; Delagnes, E.; De Masi, R.; Deck, P.; Dedek, N.; Demchenko, D.; Denisov, O. Yu.; Dhara, L.; Diaz, V.; Dibiase, N.; Dinkelbach, A. M.; Dolgopolov, A. V.; Donati, A.; Donskov, S. V.; Dorofeev, V. A.; Doshita, N.; Durand, D.; Duic, V.; Dünnweber, W.; Efremov, A.; Eversheim, P. D.; Eyrich, W.; Faessler, M.; Falaleev, V.; Fauland, P.; Ferrero, A.; Ferrero, L.; Finger, M.; Finger, M.; Fischer, H.; Franco, C.; Franz, J.; Fratnik, F.; Friedrich, J. M.; Frolov, V.; Fuchs, U.; Garfagnini, R.; Gatignon, L.; Gautheron, F.; Gavrichtchouk, O. P.; Gerassimov, S.; Geyer, R.; Gheller, J. M.; Giganon, A.; Giorgi, M.; Gobbo, B.; Goertz, S.; Gorin, A. M.; Gougnaud, F.; Grabmüller, S.; Grajek, O. A.; Grasso, A.; Grube, B.; Grünemaier, A.; Guskov, A.; Haas, F.; Hagemann, R.; Hannappel, J.; von Harrach, D.; Hasegawa, T.; Heckmann, J.; Hedicke, S.; Heinsius, F. H.; Hermann, R.; Heß, C.; Hinterberger, F.; von Hodenberg, M.; Horikawa, N.; Horikawa, S.; Horn, I.; Ilgner, C.; Ioukaev, A. I.; Ishimoto, S.; Ivanchin, I.; Ivanov, O.; Iwata, T.; Jahn, R.; Janata, A.; Joosten, R.; Jouravlev, N. I.; Kabuß, E.; Kalinnikov, V.; Kang, D.; Karstens, F.; Kastaun, W.; Ketzer, B.; Khaustov, G. V.; Khokhlov, Yu. A.; Kiefer, J.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koblitz, S.; Koivuniemi, J. H.; Kolosov, V. N.; Komissarov, E. V.; Kondo, K.; Königsmann, K.; Konoplyannikov, A. K.; Konorov, I.; Konstantinov, V. F.; Korentchenko, A. S.; Korzenev, A.; Kotzinian, A. M.; Koutchinski, N. A.; Kouznetsov, O.; Kowalik, K.; Kramer, D.; Kravchuk, N. P.; Krivokhizhin, G. V.; Kroumchtein, Z. V.; Kubart, J.; Kuhn, R.; Kukhtin, V.; Kunne, F.; Kurek, K.; Kuzmin, N. A.; Lamanna, M.; Le Goff, J. M.; Leberig, M.; Lednev, A. A.; Lehmann, A.; Levinski, V.; Levorato, S.; I Lyashenko, V.; Lichtenstadt, J.; Liska, T.; Ludwig, I.; Maggiora, A.; Maggiora, M.; Magnon, A.; Mallot, G. K.; Mann, A.; Manuilov, I. V.; Marchand, C.; Marroncle, J.; Martin, A.; Marzec, J.; Masek, L.; Massmann, F.; Matsuda, T.; Matthiä, D.; Maximov, A. N.; Menon, G.; Meyer, W.; Mielech, A.; Mikhailov, Yu. V.; Moinester, M. A.; Molinié, F.; Mota, F.; Mutter, A.; Nagel, T.; Nähle, O.; Nassalski, J.; Neliba, S.; Nerling, F.; Neyret, D.; Niebuhr, M.; Niinikoski, T.; Nikolaenko, V. I.; Nozdrin, A. A.; Olshevsky, A. G.; Ostrick, M.; Padee, A.; Pagano, P.; Panebianco, S.; Parsamyan, B.; Panzieri, D.; Paul, S.; Pawlukiewicz, B.; Pereira, H.; Peshekhonov, D. V.; Peshekhonov, V. D.; Piedigrossi, D.; Piragino, G.; Platchkov, S.; Platzer, K.; Pochodzalla, J.; Polak, J.; Polyakov, V. A.; Pontecorvo, G.; Popov, A. A.; Pretz, J.; Procureur, S.; Quintans, C.; Rajotte, J.-F.; Ramos, S.; Razaq, I.; Rebourgeard, P.; Reggiani, D.; Reicherz, G.; Richter, A.; Robinet, F.; Rocco, E.; Rondio, E.; Ropelewski, L.; Roussé, J. Y.; Rozhdestvensky, A. M.; Ryabchikov, D.; Samartsev, A. G.; Samoylenko, V. D.; Sandacz, A.; Sans Merce, M.; Santos, H.; Sapozhnikov, M. G.; Sauli, F.; Savin, I. A.; Schiavon, P.; Schill, C.; Schmidt, T.; Schmitt, H.; Schmitt, L.; Schönmeier, P.; Schroeder, W.; Seeharsch, D.; Seimetz, M.; Setter, D.; Shaligin, A.; Shevchenko, O. Yu.; Shishkin, A. A.; Siebert, H.-W.; Silva, L.; Simon, F.; Sinha, L.; Sissakian, A. N.; Slunecka, M.; Smirnov, G. I.; Sora, D.; Sosio, S.; Sozzi, F.; Srnka, A.; Stinzing, F.; Stolarski, M.; Sugonyaev, V. P.; Sulc, M.; Sulej, R.; Tarte, G.; Takabayashi, N.; Tchalishev, V. V.; Tessaro, S.; Tessarotto, F.; Teufel, A.; Thers, D.; Tkatchev, L. G.; Toeda, T.; Tokmenin, V. V.; Trippel, S.; Urban, J.; Valbuena, R.; Venugopal, G.; Virius, M.; Vlassov, N. V.; Vossen, A.; Wagner, M.; Webb, R.; Weise, E.; Weitzel, Q.; Wiedner, U.; Wiesmann, M.; Windmolders, R.; Wirth, S.; Wi?licki, W.; Wollny, H.; Zanetti, A. M.; Zaremba, K.; Zavertyaev, M.; Zhao, J.; Ziegler, R.; Ziembicki, M.; Zlobin, Y. L.; Zvyagin, A.

    2007-07-01

    The COMPASS experiment makes use of the CERN SPS high-intensity muon and hadron beams for the investigation of the nucleon spin structure and the spectroscopy of hadrons. One or more outgoing particles are detected in coincidence with the incoming muon or hadron. A large polarised target inside a superconducting solenoid is used for the measurements with the muon beam. Outgoing particles are detected by a two-stage, large angle and large momentum range spectrometer. The setup is built using several types of tracking detectors, according to the expected incident rate, required space resolution and the solid angle to be covered. Particle identification is achieved using a RICH counter and both hadron and electromagnetic calorimeters. The setup has been successfully operated from 2002 onwards using a muon beam. Data with a hadron beam were also collected in 2004. This article describes the main features and performances of the spectrometer in 2004; a short summary of the 2006 upgrade is also given.

  10. FIELD-ORIENTED CONTROL OF INDUCTION MACHINES IN THE PRESENCE OF MAGNETIC SATURATION

    Microsoft Academic Search

    E. LEVI; V. VU?KOVI?

    1989-01-01

    This paper presents derivation of the equations which describe field-oriented control of saturated induction machines. Field-oriented control principles are applied on the saturated model of induction machine and new equations are obtained, which differ significantly from the well-known model valid when the main flux saturation is absent or neglected. Rotor flux oriented control of voltage-fed and current-fed saturated induction machines

  11. Loving-Kindness and Compassion Meditation: Potential for Psychological Interventions

    PubMed Central

    Hofmann, Stefan G.; Grossman, Paul; Hinton, Devon E.

    2011-01-01

    Mindfulness-based meditation interventions have become increasingly popular in contemporary psychology. Other closely related meditation practices include loving-kindness meditation (LKM) and compassion meditation (CM), exercises oriented toward enhancing unconditional, positive emotional states of kindness and compassion. This article provides a review of the background, the techniques, and the empirical contemporary literature of LKM and CM. The literature suggests that LKM and CM are associated with an increase in positive affect and a decrease in negative affect. Preliminary findings from neuroendocrine studies indicate that CM may reduce stress-induced subjective distress and immune response. Neuroimaging studies suggest that LKM and CM may enhance activation of brain areas that are involved in emotional processing and empathy. Finally, preliminary intervention studies support application of these strategies in clinical populations. It is concluded that, when combined with empirically supported treatments, such as cognitive behavioral therapy, LKM and CM may provide potentially useful strategies for targeting a variety of different psychological problems that involve interpersonal processes, such as social anxiety, marital conflict, anger, and coping with the strains of long-term caregiving. PMID:21840289

  12. Time-varying magnetic fields: effects of orientation on chondrocyte proliferation

    Microsoft Academic Search

    J. P. Elliott; R. L. Smith; C. A. Block

    1988-01-01

    The purpose of this study was to determine the effect of orientation of pulsed electromagnetic fields (PEMFs) on cellular proliferation and extracellular matrix synthesis. Bovine articular chondrocytes were cultured in PEMFs (repetitive pulse at 72 Hz) generated using Helmholtz coils oriented either parallel (horizontal) or perpendicular (vertical) to the plane of cell adhesion. Dissipation of signal energy in the form

  13. The calm before the storm? Burnout and compassion fatigue among undergraduate nursing students.

    PubMed

    Michalec, Barret; Diefenbeck, Cynthia; Mahoney, Margaret

    2013-04-01

    Studies have consistently highlighted the deleterious impact of burnout and compassion fatigue on professional nurses' well-being and willingness to remain in the profession. Yet, as to what extent these noxious conditions are suffered among nursing students is still unclear. In this study 436 undergraduate nursing students completed surveys assessing their experiences of emotional exhaustion, depersonalization, lack of personal accomplishment, burnout, secondary traumatic stress, and compassion satisfaction (factors of burnout and compassion fatigue). There were no significant differences found between 3rd and 4th year students' reports of detrimental conditions and those of the 1st or 2nd year students. Furthermore, 4th year students reported significantly higher levels of personal accomplishment compared to 1st and 2nd year students. Semi-structured in-depth interviews with 3rd and 4th year students revealed that their clinical exposure during these years (especially during the 4th year) may enhance their other-orientation as well as promote role actualization, which may serve as protective features. Students did, however, express concern regarding an inevitable onset of burnout at some point during their professional careers. It is suggested that a key to understanding the onset and experience of burnout and compassion fatigue among nurses is to continue to examine the transition from student to professional nurse and the cultural atmosphere of nursing education compared to professional practice. PMID:23434192

  14. Quantum dynamics of the avian compass

    E-print Network

    Zachary B. Walters

    2014-09-19

    The ability of migratory birds to orient relative to the Earth's magnetic field is believed to involve a coherent superposition of two spin states of a radical electron pair. However, the mechanism by which this coherence can be maintained in the face of strong interactions with the cellular environment has remained unclear. This Letter addresses the problem of decoherence between two electron spins due to hyperfine interaction with a bath of spin 1/2 nuclei. Dynamics of the radical pair density matrix are derived and shown to yield a simple mechanism for sensing magnetic field orientation. Rates of dephasing and decoherence are calculated ab initio and found to yield millisecond coherence times, consistent with behavioral experiments.

  15. The Compassion of Zarathustra: Nietzsche on Sympathy and Strength

    E-print Network

    Gunawardena, Jeremy

    : Contemporary theorists critical of the current vogue for compassion might like to turn to Friedrich Nietzsche sentiments of sympathy or compassion.1 Most canonical philosophers would take issue with this current vogue

  16. Insect navigation: visual panoramas and the sky compass.

    PubMed

    Collett, Thomas S

    2008-11-25

    A new behavioural study shows that honeybees remember visual panoramas in a compass-based coordinate frame, linking together stored visual features of the panorama and signals from their sun-based compass. PMID:19036335

  17. Utilization of gyroscopic compass with borehole television camera in Devonian shale wells, Appalachian basin

    SciTech Connect

    Walbe, K.

    1988-08-01

    The color Borehole Television Camera has, in the three short years since its introduction in the Appalachian basin, become an extremely valuable tool in evaluating wells in Devonian shale. This has been due to the camera's ability to detect fracturing and small hydrocarbon entries that are below the resolution threshold of conventional geophysical logging. This potential of the camera has been greatly enhanced by the addition of a gyroscopic compass to the basic tool. This compass gives the added value of orientation to observed phenomena in both open and cased holes. In the open hole, the camera can be used to determine the orientation of fracturing. This feature is extremely important because fracture orientation can vary with depth, which may be the reason that some previously observed fractures make gas, whereas others within the same well bore do not. The productive fracture orientation can also be tied back to regional lineation studies. Within the open hole, the gyroscope can also be used to orient sidewall coring operations so that cores can, in addition to regular analyses, be evaluated for directional properties, such as permeability and direction of the source beds. Induced fractures, created by open-hole stress testing, can also be observed and their orientation determined.

  18. Magnetic properties of epitaxial Fe3O4 films with various crystal orientations and tunnel magnetoresistance effect at room temperature

    NASA Astrophysics Data System (ADS)

    Nagahama, Taro; Matsuda, Yuya; Tate, Kazuya; Kawai, Tomohiro; Takahashi, Nozomi; Hiratani, Shungo; Watanabe, Yusuke; Yanase, Takashi; Shimada, Toshihiro

    2014-09-01

    Fe3O4 is a ferrimagnetic spinel ferrite that exhibits electric conductivity at room temperature (RT). Although the material has been predicted to be a half metal according to ab-initio calculations, magnetic tunnel junctions (MTJs) with Fe3O4 electrodes have demonstrated a small tunnel magnetoresistance (TMR) effect. Not even the sign of the tunnel magnetoresistance ratio has been experimentally established. Here, we report on the magnetic properties of epitaxial Fe3O4 films with various crystal orientations. The films exhibited apparent crystal orientation dependence on hysteresis curves. In particular, Fe3O4(110) films exhibited in-plane uniaxial magnetic anisotropy. With respect to the squareness of hysteresis, Fe3O4 (111) demonstrated the largest squareness. Furthermore, we fabricated MTJs with Fe3O4(110) electrodes and obtained a TMR effect of -12% at RT. The negative TMR ratio corresponded to the negative spin polarization of Fe3O4 predicted from band calculations.

  19. Equilibrium intermediate-state patterns in a type-I superconducting slab in an arbitrarily oriented applied magnetic field

    DOE PAGESBeta

    Clem, John; Prozorov, Ruslan; Wijngaarden, Rinke J.

    2013-09-01

    The equilibrium topology of superconducting and normal domains in flat type-I superconductors is investigated. Important improvements with respect to previous work are that (1) the energy of the external magnetic field, as deformed by the presence of superconducting domains, is calculated in the sameway for three different topologies and (2) calculations are made for arbitrary orientation of the applied field. A phase diagram is presented for the minimum-energy topology as a function of applied field magnitude and angle. For small (large) applied fields, normal (superconducting) tubes are found, while for intermediate fields, parallel domains have a lower energy. The rangemore »of field magnitudes for which the superconducting-tubes structure is favored shrinks when the field is more in-plane oriented.« less

  20. Equilibrium intermediate-state patterns in a type-I superconducting slab in an arbitrarily oriented applied magnetic field

    DOE PAGESBeta

    Clem, John; Prozorov, Ruslan; Wijngaarden, Rinke J.

    2013-09-01

    The equilibrium topology of superconducting and normal domains in flat type-I superconductors is investigated. Important improvements with respect to previous work are that (1) the energy of the external magnetic field, as deformed by the presence of superconducting domains, is calculated in the sameway for three different topologies and (2) calculations are made for arbitrary orientation of the applied field. A phase diagram is presented for the minimum-energy topology as a function of applied field magnitude and angle. For small (large) applied fields, normal (superconducting) tubes are found, while for intermediate fields, parallel domains have a lower energy. The range of field magnitudes for which the superconducting-tubes structure is favored shrinks when the field is more in-plane oriented.

  1. Magnetic anisotropy and organization of nanoparticles in heads and antennae of neotropical leaf-cutter ants, Atta colombica

    NASA Astrophysics Data System (ADS)

    Alves, Odivaldo C.; Srygley, Robert B.; Riveros, Andre J.; Barbosa, Marcia A.; Esquivel, Darci M. S.; Wajnberg, Eliane

    2014-10-01

    Oriented magnetic nanoparticles have been suggested as a good candidate for a magnetic sensor in ants. Behavioural evidence for a magnetic compass in neotropical leaf-cutter ants, Atta colombica (Formicidae: Attini), motivated a study of the arrangement of magnetic particles in the ants’ four major body parts by measuring the angular dependence of the ferromagnetic resonance spectra at room temperature. Spectra of the thoraces and those of the abdomens showed no significant angular dependence, while those of the antennae and those of the heads exhibited a periodic dependence relative to the magnetic field. Fitting of the angular dependence of the resonant field resulted in an unexpected magnetic anisotropy with uniaxial symmetry. High values of the first order anisotropy constant were observed for the magnetic material in antennae (?2.9? × ?105?erg?cm?3) and heads (?1? × ?106?erg?cm?3) as compared to body parts of other social insects. In addition, the magnitude of the anisotropy in the heads was comparable to that observed in magnetite nanoparticles of 4–5?nm diameter. For the antennae, the mean angle of the particles’ easy magnetization axis (EA) was estimated to be 41° relative to the straightened antenna’s long axis. For the heads, EA was approximately 60° relative to the head’s axis running from midway between the spines to the clypeus. These physical characteristics indicate organized magnetic nanoparticles with a potential for directional sensitivity, which is an important feature of magnetic compasses.

  2. Nursing on empty: compassion fatigue signs, symptoms, and system interventions.

    PubMed

    Harris, Chelsia; Griffin, Mary T Quinn

    2015-01-01

    Few healthcare organizations acknowledge, discuss, or provide interventions for assisting with compassion fatigue. Yet, it is an important concept due to its individual, professional, and financial costs. This article defines compassion fatigue, differentiates it from burnout, and offers system interventions for supporting nurses and reducing compassion fatigue. PMID:25898441

  3. COMPASS: A Programmable Data Prefetcher Using Idle GPU Shaders

    E-print Network

    Lee, Hsien-Hsin "Sean"

    COMPASS: A Programmable Data Prefetcher Using Idle GPU Shaders Dong Hyuk Woo Hsien-Hsin S. Lee. In this paper, we propose COMPASS, a compute shader-assisted data prefetching scheme, to leverage the GPU cores with very lightweight architectural support, COMPASS can emulate the functionality of a hardware

  4. Virtual Compass: Relative Positioning To Sense Mobile Social Interactions

    E-print Network

    Hunt, Galen

    Virtual Compass: Relative Positioning To Sense Mobile Social Interactions Nilanjan Banerjee in availability and ac- curacy. Virtual Compass is a peer-based relative positioning system that relies solely movement. We have im- plemented Virtual Compass on mobile phones and laptops, and we eval- uate it using

  5. Pigeons combine compass and landmark guidance in familiar route navigation

    E-print Network

    Roberts, Stephen

    Pigeons combine compass and landmark guidance in familiar route navigation Dora Biro* , Robin guidance directly, or birds rely on a compass to home from familiar locations. Using miniature Global Positioning System tracking technology and clock-shift procedures, we set sun-compass and landmark infor

  6. Navigating through Mashed-up Applications with COMPASS

    E-print Network

    Milo, Tova

    Navigating through Mashed-up Applications with COMPASS 1 Tel-Aviv University 2 IBM Haifa Research others. To address this difficulty, we present COMPASS, a system that assists users in their navigation them may be non-trivial. To address this difficulty, we present here COMPASS, a sys- tem that assists

  7. A Visual Compass based on SLAM J. M. M. Montiel

    E-print Network

    Davison, Andrew

    A Visual Compass based on SLAM J. M. M. Montiel Dpt. de Informatica e Ingenieria de Sistemas cost camera hardware. Our goal is to build full 3 axis visual compass using standard low cost computer ones. We consider this visual compass as the first step for real time outdoor visual SLAM, where we

  8. Evaluation of Compass Ambiguity Resolution Performance Using Geometric-Based

    E-print Network

    Calgary, University of

    Evaluation of Compass Ambiguity Resolution Performance Using Geometric-Based Techniques Satellite Division. ABSTRACT The Chinese GNSS system, Compass, is expected to be operational in the near application areas involving Compass will be carrier-phase based precise positioning. However, the associated

  9. On the large COMPASS polarized deuteron target , N. Doshitac

    E-print Network

    Dutz, Hartmut

    On the large COMPASS polarized deuteron target J. Balla , G. Baumb , N. Doshitac , M. Finger, Jr target in the COMPASS experiment at CERN since 2001. To achieve high luminosities a large solid polarized target is used. The COMPASS polarized target consists of a high cooling power 3 He/4 He dilution refriger

  10. Structure Preserving Optimal Control of Three-Dimensional Compass Gait

    E-print Network

    Leyendecker, Sigrid

    Structure Preserving Optimal Control of Three-Dimensional Compass Gait Sigrid Leyendecker, David con- siders the optimal control of a bipedal compass gait by modeling the double stance configuration compass biped model. This control task has been previously addressed with various biped models

  11. An Ultrasonic Compass for Context-Aware Mobile Applications

    E-print Network

    An Ultrasonic Compass for Context-Aware Mobile Applications by Kevin John Wang Submitted by . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Arthur C. Smith Chairman, Department Committee on Graduate Students #12;2 #12;An Ultrasonic Compass in the Cricket system. I design and implement a prototype of this Cricket Compass using a combination of hardware

  12. Magnetic field distortions produced by protective cages around sea turtle nests: unintended consequences for orientation

    E-print Network

    Lohmann, Kenneth J.

    Magnetic field distortions produced by protective cages around sea turtle nests: unintended in cages has a high magnetic per- meability and might therefore affect the nearby field. Here we report, although whether turtles that develop in an un- natural magnetic field actually suffer navigational

  13. Detrital remanent magnetization in the solar nebula

    E-print Network

    Fu, Roger Rennan

    We introduce the theoretical basis of a new form of remanent magnetization that likely formed on primitive bodies in the solar system. Accretional detrital remanent magnetization (ADRM) operates via “compass needle”-type ...

  14. Effect of deformation route and intermediate annealing on magnetic anisotropy and magnetic properties of a 1 wt% Si non-oriented electrical steel

    NASA Astrophysics Data System (ADS)

    Sonboli, Ali; Toroghinejad, Mohammad Reza; Edris, Hossein; Szpunar, Jerzy A.

    2015-07-01

    In the present work the influence of intermediate annealing and the strain path during a two-stage cold rolling on the microstructure and texture of a 1 wt% Si non-oriented electrical steel was investigated. Different processing conditions were tasted to develop favorable texture and better understand the relation between texture and important magnetic properties. The texture parameter (TP) was defined as "theta fiber/gamma fiber" ratio. The results showed that the samples with the highest TP have the lowest magnetic anisotropy. Also average magnetocrystalline energy was calculated and it was demonstrated that the lowest energy can be correlated with the highest "theta fiber/gamma fiber" ratio. Regardless of the condition of intermediate annealing process, the uni-directional rolling produced very similar texture parameter (~2). However, the cross rolled samples have very different texture parameters upon intermediate annealing. The cross rolled samples after intermediate annealing at 650 °C have the highest texture parameter (~3). The proposed thermo-mechanical processing allow diminishing gamma fiber which is deleterious for magnetic properties of non-oriented electrical steels.

  15. Hadron Spectroscopy with COMPASS - Newest Results

    NASA Astrophysics Data System (ADS)

    Nerling, Frank

    2012-12-01

    The COMPASS experiment at the CERN SPS investigates the structure and spectrum of hadrons by scattering high energetic hadrons and polarised muons off various fixed targets. During the years 2002-2007, COMPASS focused on nucleon spin physics using 160 GeV/c polarised µ+ beams on polarised deuteron and proton targets, including measurements of the gluon contribution to the nucleon spin using longitudinal target polarisation as well as studies of transverse spin effects in the nucleon on a transversely polarised target. One major goal of the physics programme using hadron beams is the search for new states, in particular the search for JPC exotic states and glue-balls. COMPASS measures not only charged but also neutral final-state particles, allowing for investigation of new objects in different reactions and decay channels. In addition COMPASS can measure low-energy QCD constants like, e.g. the electromagnetic polarisability of the pion. Apart from a few days pilot run data taken in 2004 with a 190 GeV/c ?- beam on a Pb target, showing a significant spin-exotic JPC = 1-+ resonance at around 1660 MeV/c2, COMPASS collected high statistics with negative and positive 190 GeV/c hadron beams on a proton (H2) and nuclear (Ni, Pb) targets in 2008 and 2009. We give a selected overview of the newest results and discuss the status of various ongoing analyses.

  16. Hadron Spectroscopy with COMPASS -- Newest Results

    E-print Network

    Frank Nerling; for the COMPASS Collaboration

    2012-08-02

    The COMPASS experiment at the CERN SPS investigates the structure and spectrum of hadrons by scattering high energetic hadrons and polarised muons off various fixed targets. During the years 2002-2007, COMPASS focused on nucleon spin physics using 160 GeV/c polarised $\\mu^+$ beams on polarised deuteron and proton targets, including measurements of the gluon contribution to the nucleon spin using longitudinal target polarisation as well as studies of transverse spin effects in the nucleon on a transversely polarised target. One major goal of the physics programme using hadron beams is the search for new states, in particular the search for $J^{PC}$ exotic states and glue-balls. COMPASS measures not only charged but also neutral final-state particles, allowing for investigation of new objects in different reactions and decay channels. In addition COMPASS can measure low-energy QCD constants like, e.g. the electromagnetic polarisability of the pion. Apart from a few days pilot run data taken in 2004 with a 190 GeV/c $\\pi^{-}$ beam on a Pb target, showing a significant spin-exotic $J^{PC}$ = $1^{-+}$ resonance at around 1660 MeV/$c^{2}$, COMPASS collected high statistics with negative and positive 190 GeV/$c$ hadron beams on a proton (H$_2$) and nuclear (Ni, Pb) targets in 2008 and 2009. We give a selected overview of the newest results and discuss the status of various ongoing analyses.

  17. (Revised December 30, 2013) Magnetic Fields

    E-print Network

    Collins, Gary S.

    (Revised December 30, 2013) Magnetic Fields GOALS (1) To visualize the magnetic fields produced compasses to trace out the magnetic field lines of a single bar magnet on a large sheet of paper. (3 of the points where the magnetic fields of the Earth and the bar magnet sum to zero. INTRODUCTION A magnetic

  18. Measurement of the two-dimensional magnetostriction and the vector magnetic property for a non-oriented electrical steel sheet under stress

    NASA Astrophysics Data System (ADS)

    Kai, Y.; Tsuchida, Y.; Todaka, T.; Enokizono, M.

    2012-04-01

    This paper presents the influence of mechanical stress on the two-dimensional (2-D) magnetostriction and the vector magnetic property for a non-oriented electrical steel sheet. A six-axial strain gauge is developed in order to measure the in-plane mechanical stress and the magnetostriction of the non-oriented electrical steel sheet. The vector magnetic property and 2-D magnetostriction under tensile and compressive stress are also measured. From the results, the difference in the vector magnetic property and 2-D magnetostriction due to the applied mechanical stress is obtained.

  19. Precision Meson Spectroscopy at COMPASS

    E-print Network

    Boris Grube; for the COMPASS Collaboration

    2010-02-05

    We present first results of a partial wave analysis of the diffractive reaction $\\pi- Pb \\to \\pi- \\pi+ \\pi- Pb$ based on data from the COMPASS experiment taken during a pilot run in 2004 using a 190 GeV/c $\\pi-$ beam on a lead target. The analysis was performed in the region of squared four-momentum transfer $t'$ between 0.1 and 1.0 (GeV/c)^2. The $\\pi- \\pi+ \\pi-$ final state shows a rich spectrum of well-known resonances. In addition a spin-exotic $J^{PC} = 1^{-+}$ state with significant intensity was observed at 1.66 GeV/c^2 in the $\\rho(770) \\pi$ decay channel in natural parity exchange. The resonant nature of this state is manifest in the mass dependence of its phase difference to $J^{PC} = 1^{++}$ and $2^{-+}$ waves. The measured resonance parameters are consistent with the disputed $\\pi_1(1600)$. An outlook on the analyses of the much larger data set taken during 2008 and 2009 is given.

  20. Gluon polarization measurements at COMPASS

    NASA Astrophysics Data System (ADS)

    Silva, Luís; COMPASS Collaboration

    2012-10-01

    One of the missing keys in the present understanding of the spin structure of the nucleon is the contribution from the gluons: the so-called gluon polarization. This quantity can be determined in deep inelastic scattering (DIS) through the photon-gluon fusion process, in which two analysis methods may be used: (i) identifying open charm events or (ii) selecting events with high-transverse-momentum (high-pT) hadrons. The data used in the present work were collected in the COMPASS experiment, where a 160 GeV/c naturally polarized muon beam, impinging on a polarized nucleon fixed target, is used. Preliminary results for the gluon polarization from high-pT and open charm analyses are presented. The gluon polarization result for high-pT hadrons is divided, for the first time, into three statistically independent measurements at leading order (LO) in quantum chromodynamic (QCD). The result from open charm analysis is obtained at LO and next-to-leading order in QCD. In both analyses a new weighted method based on a neural network approach is used.

  1. Exploring Magnetic Fields in Your Environment

    NSDL National Science Digital Library

    This is a lesson about measuring magnetic field directions of Earth and in the environment. First, learners go outside, far away from buildings, power lines, or anything electrical or metal, and use compasses to identify magnetic North. Next, they use the compasses to probe whether there are any sources of magnetic fields in the local environment, including around electronic equipment such as a CD player and speakers. This is the first lesson in the second session of the Exploring Magnetism teacher guide.

  2. Performance of large pixelised Micromegas detectors in the COMPASS environment

    NASA Astrophysics Data System (ADS)

    Thibaud, F.; Abbon, P.; Andrieux, V.; Anfreville, M.; Bedfer, Y.; Burtin, E.; Capozza, L.; Coquelet, C.; Curiel, Q.; d'Hose, N.; Desforge, D.; Dupraz, K.; Durand, R.; Ferrero, A.; Giganon, A.; Jourde, D.; Kunne, F.; Magnon, A.; Makke, N.; Marchand, C.; Neyret, D.; Paul, B.; Platchkov, S.; Usseglio, M.; Vandenbroucke, M.

    2014-02-01

    New large-size Micromegas detectors are being developed for the future physics program of the COMPASS experiment at CERN. These detectors will have a pixelised readout in their center to detect particles in the beam region, where the particle flux can reach several MHz/cm2 in nominal conditions, and will have to handle high intensity hadron beams (up to a few 107 hadrons/s) with a discharge rate lower than 0.01 to 0.001 discharge/s. Several prototypes with two different discharge rate reduction technologies (preamplification stage with a GEM foil and resistive readout with buried resistors) have been studied in the COMPASS beam since 2010. Four of them have been included in the spectrometer since 2012, and have been used for the track reconstruction. Their performance (detection efficiency, space and time resolutions, and discharge rates) for different beam intensities and magnetic fields environments are presented. These detectors play an important role in the track reconstruction at very small angle; their impact is presented, with a particular emphasis on the effect of the background reduction due to an improved cluster selection.

  3. Transverse spin dependent azimuthal asymmetries at COMPASS

    E-print Network

    Bakur Parsamyan

    2013-01-29

    In semi-inclusive deep inelastic scattering of polarized leptons on a transversely polarized target eight target transverse spin-dependent azimuthal modulations are allowed. In the QCD parton model half of these asymmetries can be interpreted within the leading order approach and the other four are twist-three contributions. The first two leading twist asymmetries extracted by HERMES and COMPASS experiments are related: one to the transversity distribution and the Collins effect, the other to the Sivers distribution function. These results triggered a lot of interest in the past few years and allowed the first extractions of the transversity and the Sivers distribution functions of nucleon. The remaining six asymmetries were obtained by the COMPASS experiment using a 160 GeV/c longitudinally polarized muon beam and transversely polarized deuteron and proton targets. Here we review preliminary results from COMPASS proton data of 2007.

  4. Hadron Spectroscopy with COMPASS at CERN

    E-print Network

    Karin Schoenning for the COMPASS collaboration

    2011-12-02

    The aim of the COMPASS hadron programme is to study the light-quark hadron spectrum, and in particular, to search for evidence of hybrids and glueballs. COMPASS is a fixed-target experiment at the CERN SPS and features a two-stage spectrometer with high momentum resolution, large acceptance, particle identification and calorimetry. A short pilot run in 2004 resulted in the observation of a spin-exotic state with $J^{PC} = 1^{-+}$ consistent with the debated $\\pi1(1600)$. In addition, Coulomb production at low momentum transfer data provide a test of Chiral Perturbation Theory. During 2008 and 2009, a world leading data set was collected with hadron beam which is currently being analysed. The large statistics allows for a thorough decomposition of the data into partial waves. The COMPASS hadron data span over a broad range of channels and shed light on several different aspects of QCD.

  5. Polarized Drell-Yan studies at COMPASS

    NASA Astrophysics Data System (ADS)

    Quintans, Catarina

    2014-03-01

    The COMPASS experiment at CERN will soon start a new series of measurements using a pion beam and a transversely polarized target. The study of the polarized Drell-Yan process will provide an insight of the transverse momentum dependent parton distribution functions (TMDs), which is complementary to their extraction from semi-inclusive deep inelastic scattering (SIDIS), previously measured in COMPASS. The sign change of Sivers and Boer-Mulders TMDs, when accessed from SIDIS or Drell-Yan, is predicted by theory. Its experimental observation is considered an essential test of the TMD approach. The experimental aspects of the Drell-Yan measurement in COMPASS are discussed. The set-up optimization, driven by the results of several beam tests are presented, as well as the expected event rates and statistical errors of the azimuthal asymmetries.

  6. Time-varying magnetic fields: effects of orientation on chondrocyte proliferation

    SciTech Connect

    Elliott, J.P.; Smith, R.L.; Block, C.A.

    1988-01-01

    The purpose of this study was to determine the effect of orientation of pulsed electromagnetic fields (PEMFs) on cellular proliferation and extracellular matrix synthesis. Bovine articular chondrocytes were cultured in PEMFs (repetitive pulse at 72 Hz) generated using Helmholtz coils oriented either parallel (horizontal) or perpendicular (vertical) to the plane of cell adhesion. Dissipation of signal energy in the form of heat increased the temperature of the PEMF coils by 2 degrees C and the tissue culture medium by 1 degree C. Therefore, control coils, which emitted no PEMFs, were heated to the temperature of PEMF coils by circulating water. Chondrocytes were cultured in 16-mm-well culture plates, and the data for individual wells were pooled as triplicates. Although not observed by microscopic examination of individual wells, positionally dependent electric field effects may be minimized by this approach. PEMFs generated by coils oriented vertically significantly decreased chondrocyte proliferation. The effect was dependent on the concentration of serum in the culture media. At 3% serum concentration, the total cell number attained after 10 days of culture was reduced by 50% in stimulated cultures when compared with controls. At 5% serum concentration, there was no effect. PEMFs applied by coils oriented horizontally did not alter proliferation of articular chondrocytes. PEMFs had no effect on synthesis of extracellular matrix by chondrocytes plated at high density, irrespective of orientation.

  7. Nucleon Spin And Structure Studies With COMPASS

    SciTech Connect

    Platchkov, Stephane [CERN, Geneva (Switzerland); CEA-Saclay, DSM/DAPNIA, Gif-sur-Yvette (France)

    2006-07-11

    The COMPASS experiment at CERN investigates nucleon structure and spectroscopy with high-intensity muon and hadron beams. Between 2002 and 2004 COMPASS has mainly concentrated on the spin structure of the nucleon via deep-inelastic scattering of polarized muons on polarized nucleons. First results include measurements of the gluon contribution to the nucleon spin via charm production and high-pt pairs, {lambda} polarization, vector-meson production, Collins and Sivers asymmetries, inclusive and semi-inclusive deep-inelastic scattering asymmetries and a search for pentaquark states. A short overview of these results is presented.

  8. Diffractive {rho}0 production at COMPASS

    SciTech Connect

    D'Hose, N. [CEA-Saclay, DSM/DAPNIA/SphN, F-91191 Gif-sur-Yvette Cedex (France)

    2005-10-06

    Diffractive leptoproduction of {rho}0 mesons, {mu} + N {yields} {mu} + N + {rho} is measured at COMPASS at < W > = 10 GeV over a wide range of Q2, 0.01 < Q2 < 10 GeV2. Angular distributions allow to determine spin density matrix elements. Preliminary results from COMPASS 2002 data are presented. They are consistent with a substantial increase of R = {sigma}L/{sigma}T with Q2 and a weak violation of SCHC, in agreement with other high energy experiments.

  9. Program of COMPASS-II at CERN

    NASA Astrophysics Data System (ADS)

    Sandacz, A.

    2015-02-01

    COMPASS collaboration has started in 2012 a five-year program of new measurements, which are outlined in the 'COMPASS-II' proposal. The two new major projects of the proposal are measurements of polarized Drell-Yan process in ?- scattering off transversely polarized protons and studies of GPDs via measurements of Deeply Virtual Compton Scattering and Hard Exclusive Meson Production in muon scattering off a liquid hydrogen target. In addition, high statistics SIDSI measurements with muon beams and a study of charged pion and kaon polarizabilities via Primakoff reactions with hadron beams are also foreseen as a part of this program.

  10. How dim is dim? Precision of the celestial compass in moonlight and sunlight.

    PubMed

    Dacke, M; Byrne, M J; Baird, E; Scholtz, C H; Warrant, E J

    2011-03-12

    Prominent in the sky, but not visible to humans, is a pattern of polarized skylight formed around both the Sun and the Moon. Dung beetles are, at present, the only animal group known to use the much dimmer polarization pattern formed around the Moon as a compass cue for maintaining travel direction. However, the Moon is not visible every night and the intensity of the celestial polarization pattern gradually declines as the Moon wanes. Therefore, for nocturnal orientation on all moonlit nights, the absolute sensitivity of the dung beetle's polarization detector may limit the precision of this behaviour. To test this, we studied the straight-line foraging behaviour of the nocturnal ball-rolling dung beetle Scarabaeus satyrus to establish when the Moon is too dim--and the polarization pattern too weak--to provide a reliable cue for orientation. Our results show that celestial orientation is as accurate during crescent Moon as it is during full Moon. Moreover, this orientation accuracy is equal to that measured for diurnal species that orient under the 100 million times brighter polarization pattern formed around the Sun. This indicates that, in nocturnal species, the sensitivity of the optical polarization compass can be greatly increased without any loss of precision. PMID:21282173

  11. Measuring Earth's Magnetic Field Simply.

    ERIC Educational Resources Information Center

    Stewart, Gay B.

    2000-01-01

    Describes a method for measuring the earth's magnetic field using an empty toilet paper tube, copper wire, clear tape, a battery, a linear variable resistor, a small compass, cardboard, a protractor, and an ammeter. (WRM)

  12. Microstructure and magnetic properties of (001) oriented FePt/B{sub 4}C composite films

    SciTech Connect

    Yang, F. J.; Wang Hao; Wang, H. B.; Cao, X.; Yang, C. P.; Li, Q.; Zhou, M. J.; Chong, Y. M.; Zhang, W. J. [Faculty of Physics and Electronic Technology and Key Laboratory of Ferro- and Piezo-Electric Materials and Devices, Hubei University, Wuhan 430062 (China); Department of Physics, Chinese University of Hong Kong, Hong Kong (China); Department of Physics, City University of Hong Kong, N.T. Hong Kong (China)

    2007-11-15

    FePt/B{sub 4}C multilayer composite films have been prepared by magnetron sputtering and subsequent annealing in vacuum. It was found that the B{sub 4}C layers effectively serve as spacers to separate the FePt layers, enhancing (001) orientation of FePt alloy. Our results show that highly (001) oriented [Fe{sub 45}Pt{sub 55}(8 nm)/B{sub 4}C (4 nm)]{sub 3} film with satisfactory perpendicular coercivity (4.75 kOe) has significant potential as a perpendicular recording medium.

  13. Anisotropic Water Diffusion in Macroscopically Oriented Lipid Bilayers Studied by Pulsed Magnetic Field Gradient NMR

    Microsoft Academic Search

    Pär Wästerby; Greger Orädd; Göran Lindblom

    2002-01-01

    The anisotropy, D\\/\\/\\/D?, of water diffusion in fully hydrated bilayers of dimyristoylphosphatidylcholine at 29°C has been measured by pulsed magnetic field gradient (pfg) NMR. By using NMR imaging hardware to produce magnetic field gradients in an arbitrary direction with respect to a stack of macroscopically aligned lipid bilayers, translational diffusion of water was measured as a function of the angle

  14. Anchor Node Localization for Wireless Sensor Networks Using Video and Compass Information Fusion

    PubMed Central

    Pescaru, Dan; Curiac, Daniel-Ioan

    2014-01-01

    Distributed sensing, computing and communication capabilities of wireless sensor networks require, in most situations, an efficient node localization procedure. In the case of random deployments in harsh or hostile environments, a general localization process within global coordinates is based on a set of anchor nodes able to determine their own position using GPS receivers. In this paper we propose another anchor node localization technique that can be used when GPS devices cannot accomplish their mission or are considered to be too expensive. This novel technique is based on the fusion of video and compass data acquired by the anchor nodes and is especially suitable for video- or multimedia-based wireless sensor networks. For these types of wireless networks the presence of video cameras is intrinsic, while the presence of digital compasses is also required for identifying the cameras' orientations. PMID:24594614

  15. 2007-2009 UC Regents Updated: June 24, 2009 Career Compass Job

    E-print Network

    Jacobs, Lucia

    © 2007-2009 UC Regents Updated: June 24, 2009 Career Compass Job Titles Go Live! May - June 2009 #12;2 Career Compass Job Titles Go Live! May 1, 2009 Career Compass Job TitlesCareer Compass Job Titles Go Live!Go Live! May 1, 2009May 1, 2009 Brief History of Career Compass Goals Total Rewards Where

  16. Temperature dependence of magnetic properties of oriented MnBi films

    Microsoft Academic Search

    W. K. Unger

    1971-01-01

    The temperature dependence of the Faraday rotation and the coercive field of oriented low-temperature phase and quenched high-temperature phase MnBi films was measured between 20 °C and 400 °C. A dependence of the Curie temperature of low temperature phase films on the film thickness was found and measured.

  17. The orientation and navigation of juvenile alligators: evidence of magnetic sensitivity

    Microsoft Academic Search

    Gordon H. Rodda

    1984-01-01

    Summary Displaced juvenile alligators,Alligator mississipiensis, were released on land in a 9 m diameter dodecagonal arena to test their ability to orient in the absence of terrestrial landmarks. Navigational ability seemed to improve with age. When displaced along a fairly direct route yearlings (age 7–14 months) compensated for their displacement, moving in the direction from the arena to their home

  18. AMS measurements on obsidian from the Inyo Domes, CA: a comparison of magnetic and mineral preferred orientation fabrics

    NASA Astrophysics Data System (ADS)

    Cañón-Tapia, Edgardo; Castro, Jonathan

    2004-06-01

    Measurements of the anisotropy of magnetic susceptibility (AMS) on lavas can yield information concerning flow directions, deformation regimes, and relative shear rates. Here we report results of measurements made on samples of rhyolitic obsidian collected from Obsidian Dome, CA. Comparisons of AMS measurements with previously determined 3D microlite orientation distributions in these samples serve as a calibration of the AMS technique. Despite the low values of bulk susceptibility (1.06-7.04×10 -3 SI) found in the dome relative to typical values in basalts (10 -2 SI), the degree of anisotropy is extremely high in all specimens (3.4-10.7). Furthermore, susceptibility tensors exhibit a wide range of shapes varying from prolate to triaxial and flattened ellipsoids ( B parameter from -8.6 to +6.4) corresponding to various degrees of microlite dispersion. Our results also indicate that despite the tight clustering of principal susceptibility axes obtained on each site, bulk flow directions inferred from the orientations of kmax axes may be misleading because the orientation of the local extension changes from place to place within the dome. However, it is shown that the AMS of each specimen provides a good measure of the direction of local extension. Consequently, it is possible to interpret spatial variations in flow regime from systematic changes in the orientation of principal susceptibility axes. As the proposed association between the local deformation regime and AMS is strongly dependent on the aspect ratio of the crystals embedded in the flowing lava, some caution must be exerted when interpreting AMS results from other flows, and a direct comparison between different flows may not be granted in many occasions.

  19. Transfer of directional information between the polarization compass and the sun compass in desert ants.

    PubMed

    Lebhardt, Fleur; Ronacher, Bernhard

    2015-06-01

    Desert ants, Cataglyphis fortis, perform large foraging excursions during which they continuously compute a home vector that allows them to return to the nest on the shortest way. This type of navigation, termed path integration, needs a compass system and an odometer. Ants use several cues to determine their walking direction, two of the most important ones being the sun position and the polarization pattern of the sky. We tested whether an information transfer is possible from one compass system to the other, which depend on different anatomical substrates. Since the sky's polarization pattern is detected by UV-photoreceptors located in the dorsal rim area (DRA), we used an orange Perspex filter that eliminated the UV part of the spectrum to prevent the use of the polarization compass. The use of the sun compass could be excluded by appropriate screens. In the critical tests the ants had learned a nest-feeder direction with e.g. the sun compass only, and were later tested with the polarization compass, or vice versa. The results show that a transfer is possible in both directions. PMID:25062650

  20. Practical compassions: repertoires of practice and compassion talk in acute mental healthcare.

    PubMed

    Brown, Brian; Crawford, Paul; Gilbert, Paul; Gilbert, Jean; Gale, Corinne

    2014-03-01

    This article reports an exploratory study of the concept of compassion in the work of 20 mental health practitioners in a UK Midlands facility. Using notions of practice derived from phenomenology and Bourdieusian sociology and notions of emotional labour we identify two contrasting interpretive repertoires in discussions of compassion. The first, the practical compassion repertoire, evokes the practical, physical and bodily aspects of compassion. It involves organising being with patients, playing games, anticipating disruption and taking them outside for cigarettes. Practitioners described being aware that these practical, bodily activities could lead to patients 'opening up', disclosing their interior concerns and enabling practical, compassionate mental health work to take place. In contrast, the second, organisational repertoire, concerns organisational constraints on compassionate practice. The shortage of staff, the record-keeping and internal processes of quality control were seen as time-greedy and apt to detract from contact with patients. The findings are discussed in relation to Bourdieu and Merleau-Ponty's phenomenological accounts of practice and habit and set in context in the growing interest in placing compassion centrally in healthcare. We also explore how the exercise of compassion in the way our participants describe it can afford the more effective exercise of medical power. PMID:24117523

  1. Artifacts in the Wake: Leadership via an Oriented Compass Model

    ERIC Educational Resources Information Center

    Fallon, Paul D.

    2013-01-01

    Although inextricable, the act of leading, the leader, and outcome of leadership are unique entities. Lack of such differentiation may ensnare novice leaders in broad suppositions. This conceptual article introduces a tool for analyzing leadership. Leaders can leverage the model to evaluate the act of leading, in route, via a measurable trajectory…

  2. Visualizing Magnetic Field Lines

    NSDL National Science Digital Library

    2014-09-18

    In this activity, students take the age old concept of etch-a-sketch a step further. Using iron filings, students begin visualizing magnetic field lines. To do so, students use a compass to read the direction of the magnet's magnetic field. Then, students observe the behavior of iron filings near that magnet as they rotate the filings about the magnet. Finally, students study the behavior of iron filings suspended in mineral oil which displays the magnetic field in three dimensions.

  3. Prediction of magnetic orientation in driver gas associated -Bz events. [in interplanetary medium observed at earth when solar source is identified

    NASA Technical Reports Server (NTRS)

    Hoeksema, J. T.; Zhao, Xuepu

    1992-01-01

    The source regions of five strong -Bz events detected at 1 AU for which solar sources were identified by Tang et al. (1989) and Tsurutani et al. (1992) are investigated in order to determine whether the magnetic orientation of driver gas in the interplanetary medium observed at the earth can be predicted when its solar source is identified. Three -Bz events were traced to flare-associated coronal mass ejections (CMEs), one to an eruptive prominence associated CME, and one to three possible solar sources. The computed magnetic orientations at the candidate 'release height' (the height where the front of a CME ceases to accelerate) above the flare sites associated with CMEs show the existence of the expected southward field component. It is concluded that the magnetic orientation in flare-associated CME generated driver gas may be predictable.

  4. Walking alongside Children as They Form Compassion

    ERIC Educational Resources Information Center

    Sanders, Wendy Hinrichs

    2010-01-01

    The affluence in the United States in the recent past has made it tempting to indulge children in individual achievement within a culture of abundance. Parents and teachers worry over how to teach compassion in a culture of abundance and competition for personal success, where children's time is over-scheduled and they are geographically dispersed…

  5. Compassion fatigue: nurse grief…who cares?

    Microsoft Academic Search

    Barbara Rubel

    2004-01-01

    The loss of a patient or a coworker through sudden death can be a shattering experience. The purpose of this presentation was to provide information on compassion fatigue. This presentation covered the affect of repeated traumatic death on nurses. The presentation was divided into two parts. In the first part, the presenter reviewed nurses as disenfranchised grievers, identified characteristics of

  6. Measurement of the gluon polarisation at COMPASS

    E-print Network

    G. Brona; for the COMPASS Collaboration

    2007-05-16

    COMPASS experiment measurements of the gluon polarisation in nucleon, DeltaG/G are reviewed. Two different approaches based on tagging the Photon Gluon Fusion process are described. They rely on the open charm meson or high-p_T hadron pairs detection.

  7. COMPASS - a facility to study QCD

    E-print Network

    Eva-Maria Kabuss

    2011-09-13

    An overview on the new COMPASS II experimental programme is presented. The main topics include a study of Primakoff reactions, generalised parton distributions via deeply virtual Compton scattering and transverse momentum dependent distributions in Drell-Yan processes in the pion scattering off polarised protons. Moreover, the studies of semi-inclusive deep inelastic scattering on unpolarised target will be continued.

  8. Computer-Assisted Scheduling System (COMPASS)

    NASA Technical Reports Server (NTRS)

    Fox, Barry R.

    1992-01-01

    COMPASS is interactive planning and scheduling software system used like spreadsheet. System places activities only at feasible times, taking into consideration all constraints imposed upon activity and resources it requires. Version 1.4 written in Ada and contains standard X-Windows interfaces written in C.

  9. New COMPASS results on Collins and Sivers asymmetries

    E-print Network

    F. Bradamante; for the COMPASS Collaboration

    2011-11-03

    The study of transverse spin and transverse momentum effects is an important part of the scientific program of COMPASS, a fixed target experiment at the CERN SPS. For these studies a 160 GeV/c momentum muon beam is scattered on a transversely polarized nucleon target, and the scattered muon and the forward going hadrons produced in DIS processes are reconstructed and identified in a magnetic spectrometer. The measurements have been performed on a deuteron target in 2002, 2003 and 2004, and on a proton target in 2007 and 2010. The results obtained for the Collins and Sivers asymmetries from the data collected in 2010 are here presented for the first time. They nicely confirm the findings of the 2007 run and allow for reduction of the errors by more than a factor of two.

  10. Comment on "Quantum Control and Entanglement in a Chemical Compass"

    E-print Network

    I. K. Kominis

    2011-02-19

    In this comment we show that the avian compass entanglement considerations of J. Cai, G. G. Guerreschi and H. J. Briegel (Phys. Rev. Lett. 104, 220502 (2010)) result in unphysical predictions on the magnetic sensitivity of this biochemical sensor. As well known from a series of papers on precision measurements and detailed derivations of standard quantum limits, not taking into account decoherence results in an overestimate of the entanglement lifetime, and this is the case at hand. The entanglement lifetime is wrongly assumed by the authors to be independent of the reaction time (the inverse of the recombination rate) and hence it is grossly overestimated. This is so because the spin coherence lifetime is limited by the reaction time, and the entanglement lifetime cannot be any longer.

  11. Meson structure in soft hadronic reactions at COMPASS

    SciTech Connect

    Colantoni, M. [Universita del Piemonte Orientate e INFN-To (Italy)

    2006-02-11

    The measurement of the electric ({alpha}-bar{pi}) and magnetic ({beta}-bar{pi}) pion polarizabilities supplies a significant test of QCD predictions in particular in the framework of the chiral perturbation theory.In this perspective we have measured with the COMPASS spectrometer the t-dependence of the cross section for the reactions: {pi}- + Z {yields} {pi}- + Z + {gamma}, and {mu}- + Z {yields} {mu}- + Z + {gamma} selecting events corresponding to the Compton {pi}{gamma} and {mu}{gamma} scattering respectively. From a fit of the data of the first reaction we can extract {alpha}-bar{pi} and {beta}-bar{pi}, from those of the second the point-like contribution. This procedure minimizes the systematic errors. Details on the experiment and the present status of the analysis of the data collected in 2004 will be discussed.

  12. Sustained Quantum Coherence and Entanglement in the Avian Compass

    E-print Network

    Erik Gauger; Elisabeth Rieper; John J. L. Morton; Simon C. Benjamin; Vlatko Vedral

    2011-01-30

    In artificial systems, quantum superposition and entanglement typically decay rapidly unless cryogenic temperatures are used. Could life have evolved to exploit such delicate phenomena? Certain migratory birds have the ability to sense very subtle variations in Earth's magnetic field. Here we apply quantum information theory and the widely accepted "radical pair" model to analyze recent experimental observations of the avian compass. We find that superposition and entanglement are sustained in this living system for at least tens of microseconds, exceeding the durations achieved in the best comparable man-made molecular systems. This conclusion is starkly at variance with the view that life is too "warm and wet" for such quantum phenomena to endure.

  13. Use of the earth's magnetic field by orienting cave salamanders ( Eurycea lucifuga )

    Microsoft Academic Search

    John B. Phillips

    1977-01-01

    Two groups ofEurycea lucifuga were trained to move bidirectionally within separate training corridors by alternately supplying moisture to limestone-filled compartments located at each end. Both corridors were aligned horizontally along the magnetic North-South axis of the earth. One corridor was enclosed within a cube coil which rotated the magnetic field horizontally 90° clockwise, so that the group contained in this

  14. Quaternion-based extended Kalman filter for determining orientation by inertial and magnetic sensing

    Microsoft Academic Search

    Angelo M. Sabatini

    2006-01-01

    In this paper, a quaternion based extended Kalman filter (EKF) is developed for determining the orientation of a rigid body from the outputs of a sensor which is configured as the integration of a tri-axis gyro and an aiding system mechanized using a tri-axis accelerometer and a tri-axis magnetometer. The suggested applications are for studies in the field of human

  15. Magnetic properties of Mn{sub 3}O{sub 4} film with a coexistence of two preferential orientations

    SciTech Connect

    Ren, Lizhu; Zhou, Wenqi; Wang, Yunjia; Meng, Meng; Wu, Shuxiang; Li, Shuwei, E-mail: stslsw@mail.sysu.edu.cn [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China)

    2014-07-14

    A Mn{sub 3}O{sub 4} film with a coexistence of two preferential orientations has been grown on a Pt(111)//Si(100) substrate by plasma-assisted molecular beam epitaxy. The structural characteristics and chemical compositions of the film are investigated by using X-ray diffraction, Raman, and X-ray photoelectron spectra in detail. Together with the magnetic tests, the film is demonstrated to be a polycrystalline hausmannite Mn{sub 3}O{sub 4} with no other impurities. Moreover, the hysteresis loops of the film are found to display a step or a characteristic shrinking at low fields. On the other hand, similar magnetic characteristics have also been discovered on the film with two phases grown on a MgAl{sub 2}O{sub 4}(001) substrate. In our opinion, considering the large magnetocrystalline anisotropy and shape anisotropy of the single crystal Mn{sub 3}O{sub 4} film reported in previous works, the special structures and phases of the two films result in both of them as soft+hard magnetic composites, in agreement with some other reports.

  16. The Brain’s Orienting Response: An Event-Related Functional Magnetic Resonance Imaging Investigation

    PubMed Central

    Friedman, David; Goldman, Robin; Stern, Yaakov; Brown, Truman R.

    2009-01-01

    An important function of the brain’s orienting response is to enable the evaluation of novel, environmental events in order to prepare for potential behavioral action. Here, we assessed the event-related hemodynamic (erfMRI) correlates of this phenomenon using unexpected (i.e., novel) environmental sounds presented within the context of an auditory novelty oddball paradigm. In ERP investigations of the novelty oddball, repetition of the identical novel sound leads to habituation of the novelty P3, an ERP sign of the orienting response. Repetition also leads to an enhancement of a subsequent positivity that appears to reflect semantic analysis of the environmental sounds. In this adaptation for erfMRI recording, frequent tones were intermixed randomly with infrequent target tones and equally infrequent novel, environmental sounds. Subjects responded via speeded button press to targets. To assess habituation, some of the environmental sounds were repeated 2 blocks after their initial presentation. As expected, novel sounds and target tones led to activation of widespread, but somewhat different, neural networks. Contrary to expectation, however, there were no significant areas in which activation was reduced in response to second compared to first presentations of the novel sounds. Conversely, novel sounds relative to target tones engendered activity in the inferior frontal gyrus (BA 45) consistent with semantic analysis of these events. We conclude that a key concomitant of the orienting response is the extraction of meaning, thereby enabling one to determine the significance of the environmental perturbation and take appropriate goal-directed action. PMID:18465750

  17. COMPASS, the COMmunity Petascale project for Accelerator Science and Simulation, a broad computational accelerator physics

    E-print Network

    Geddes, Cameron Guy Robinson

    COMPASS, the COMmunity Petascale project for Accelerator Science and Simulation, a broad at Lawrence Livermore National Laboratory. #12;COMPASS, the COMmunity Petascale project for Accelerator for materials studies. COMPASS, the Community Petascale Project for Accelerator Science and Simulation

  18. Orientation-dependent magnetism and orbital structure of strained YTiO3 films on LaAlO3 substrates

    NASA Astrophysics Data System (ADS)

    Huang, Xin; Xu, Qingyu; Dong, Shuai

    2015-05-01

    The strain tuned magnetism of YTiO3 film grown on the LaAlO3 (110) substrate is studied by the method of the first principles, and compared with that of the (001)-oriented one. The obtained magnetism is totally different, which is ferromagnetic for the film on the (110) substrate but A-type antiferromagnetic on the (001) one. This orientation-dependent magnetism is attributed to the subtle orbital ordering of YTiO3 film. The dxz/dyz-type orbital ordering is predominant for the (001) one, but for the (110) case, the dxy orbital is mostly occupied plus a few contribution from the dxz/dyz orbital. Moreover, the lattice mismatch is modest for the (110) case but more serious for the (001) one, which is also responsible for this contrasting magnetism.

  19. Effect of the phosphate component of electrical insulating coating on the magnetic losses in grain-oriented electrical steel

    NASA Astrophysics Data System (ADS)

    Karenina, L. S.; Korzunin, G. S.; Puzhevich, R. B.

    2011-01-01

    It is shown that one of the main methods improving quality of a grain-oriented electrical sheet steel (GOES) is the deposition of an electrical insulating coating (EIC) on its surface, which produces elastic tensile stresses in the metal. The EIC represents a composite consisting of a glass film and a phosphate coating deposited on it. Investigations performed in this direction are reviewed. A complex of the industrial experiments has been carried out, which were directed to studying the effect of both the insulating coating as a whole and, separately, its phosphate component (PC) on the level of magnetic losses. The values of elastic tensile stresses produced in the metal by the EIC and PC are presented. This work has been performed under the conditions of the OOO VIZ-stal' (Verkneisetsk Factory).

  20. Mapping Magnetic Field Lines

    NSDL National Science Digital Library

    This is a lesson about the magnetic field of a bar magnet. The lesson begins with an introductory discussion with learners about magnetism to draw out any misconceptions that may be in their minds. Then, learners freely experiment with bar magnets and various materials, such as paper clips, rulers, copper or aluminum wire, and pencils, to discover that magnets attract metals containing iron, nickel, and/or cobalt but not most other materials. Next, learners experiment with using a magnetic compass to discover how it is affected by the magnet and then draw the magnetic field lines of the magnet by putting dots at the location of the compass arrow. This is the first lesson in the first session of the Exploring Magnetism teacher guide.

  1. A study of orientation ratio in longitudinal magnetic thin-film media on plasma-treated textured substrates

    NASA Astrophysics Data System (ADS)

    Chen, Y. J.; Dai, D. Y.; Zhao, H. B.; Pang, S. I.; Yin, J. H.; Wu, L. J.; Guan, T. P.; Piramanayagam, S. N.; Wang, J. P.

    2005-06-01

    The effects of plasma treatment of textured substrates on orientation ratio (OR) as well as in-plane Cr(200)/Co(11.0) preferred orientation (PO) and coercivity (Hc) in longitudinal magnetic recording media have been systematically investigated. OR is found to increase by ˜0.2 0.3 with enhanced PO and Hc for samples with slightly rf sputter etched substrates. Further Ar+ plasma dry etching (higher power/longer duration) leads to a slow decrease of OR to ?1, then a worsened/vanishing PO and finally a drastic drop in Hc. The origin of OR is primarily attributed to stress effects (of most importance being the anisotropic stress induced preferential easy axis distribution), with anisotropic topography and PO as two necessary preconditions for OR >1. Ion beam bombardment induced chemical/structural modifications and residual stress in the substrate surface layer may play important roles in film growth/structures/properties and therefore in the mechanisms of the evolution of OR with plasma treatment.

  2. Relative orientations of the magnetic fields and major axes radio galaxies

    Microsoft Academic Search

    Andreasyan

    1986-01-01

    A statistical analysis of the observational data on 97 objects yields the results that in the more elongated radio galaxies the direction of the magnetic field averaged over the surface of the radio image is almost parallel to the major axis of the radio image. In the less elongated ones, these directions subtend large angles, close to 90 degrees. It

  3. Position and Orientation Accuracy Analysis for Wireless Endoscope Magnetic Field Based Localization System Design

    Microsoft Academic Search

    Kegen Yu; Gengfa Fang; Eryk Dutkiewicz

    2010-01-01

    This paper focuses on wireless capsule endoscope magnetic field based localization by using a linear algorithm, an unconstrained optimization method and a constrained optimization method. Eight sensor populations are employed for performance evaluation. For each of five sensor populations, four different sensor configurations are investigated, which represent potential sensor placements in practice. Accuracy is evaluated over a range of noise

  4. Compass roses on the Book of Navigation ( Kitab-? Bahriye): Declination data source for geomagnetic field models

    NASA Astrophysics Data System (ADS)

    Yilmaz, Ibrahim; Gullu, Mevlut; Yilmaz, Mustafa; Dereli, Mehmet A.

    2010-10-01

    The Earth is surrounded by a geomagnetic field that is generated by dynamo processes in the core like a gigantic magnet. The Earth's geomagnetic field shifts with time and location. There has been a comprehensive effort for modelling the geomagnetic field of the Earth at regional and global scales by several researchers in the recent decades. The magnetic data from historical sources have a great importance in geomagnetic field modelling. The declination was the first measured geomagnetic field element with the early use of compasses for navigation. In this study the declination values estimated from compass roses drawn on the Book of Navigation ( Kitab-? Bahriye) that are georeferenced by an artificial neural network are compared to the declination values based on the geomagnetic field models CALS3K.3 and SCHA.DIF.3K. The results show that the compass roses drawn on the portolan charts of Kitab-? Bahriye can be used as declination data sources for regional or global geomagnetic field models.

  5. Magnetic characterization of noninteracting, randomly oriented, nanometer-scale ferrimagnetic particles

    NASA Astrophysics Data System (ADS)

    Cao, Changqian; Tian, Lanxiang; Liu, Qingsong; Liu, Weifeng; Chen, Guanjun; Pan, Yongxin

    2010-07-01

    Studying the magnetic properties of ultrafine nanometer-scale ferrimagnetic particles (<10 nm) is vital to our understanding of superparamagnetism and its applications to environmental magnetism, biogeomagnetism, iron biomineralization, and biomedical technology. However, magnetic properties of the ultrafine nanometer-sized ferrimagnetic grains are very poorly constrained because of ambiguities caused by particle magnetostatic interactions and unknown size distributions. To resolve these problems, we synthesized magnetoferritins using the recombinant human H chain ferritin (HFn). These ferrimagnetic HFn were further purified through size exclusion chromatography to obtain monodispersed ferrimagnetic HFn. Transmission electron microscopy revealed that the purified ferrimagnetic HFn are monodispersed and each consists of an iron oxide core (magnetite or maghemite) with an average core diameter of 3.9 ± 1.1 nm imbedded in an intact protein shell. The R value of the Wohlfarth-Cisowski test measured at 5 K is 0.5, indicating no magnetostatic interactions. The saturation isothermal remanent magnetization acquired at 5 K decreased rapidly with increasing temperature with a median unblocking temperature of 8.2 K. The preexponential frequency factor f0 determined by AC susceptibility is (9.2 ± 7.9) × 1010 Hz. The extrapolated Mrs/Ms and Bcr/Bc at 0 K are 0.5 and 1.12, respectively, suggesting that the ferrimagnetic HFn cores are dominated by uniaxial anisotropy. The calculated effective magnetic anisotropy energy constant Keff = 1.2 × 105 J/m3, which is larger than previously reported values for bulk magnetite and/or maghemite or magnetoferritin and is attributed to the effect of surface anisotropy. These data provide useful insights into superparamagnetism as well as biomineralization of ultrafine ferrimagnetic particles.

  6. ComPaSS: efficient communication services for scalable architectures

    Microsoft Academic Search

    Philip K. McKinley; Hong Xu; Edgar T. Kalns; Lionel M. Ni

    1992-01-01

    In massively parallel computers (MPCS), efictent communicat~on among processors is critzcal to performance. This paper describes the znzt~al implementation of the ComPaSS communication library to support scalable software development in MPCS. ComPaSS provides hxgh-level global commun~cation operations for both data manipulation and process control, many of which are based upon a small set of low-level communication prim$ttves. The ComPaSS ltbrary

  7. Self-compassion, Achievement Goals, and Coping with Academic Failure

    Microsoft Academic Search

    KRISTIN D. NEFF; Ya-Ping Hsieh; Kullaya Dejitterat

    2005-01-01

    Two studies examined the relationship between self-compassion, academic achievement goals, and coping with perceived academic failure among undergraduates. Self-compassion entails being kind to oneself in instances of failure, perceiving one's experiences as part of the larger human experience, and holding painful feelings in mindful awareness. Study 1 (N?=?222) found that self-compassion was positively associated with mastery goals and negatively associated

  8. Smartstones: a small e-compass, accelerometer and gyroscope embedded in stones

    NASA Astrophysics Data System (ADS)

    Gronz, Oliver; Hiller, Priska H.; Wirtz, Stefan; Becker, Kerstin; Iserloh, Thomas; Aberle, Jochen; Casper, Markus C.

    2015-04-01

    Pebbles or rock fragments influence soil erosion processes in various ways: they can protect the soil but also enhance the erosion as soon as they are moved by water and impact onto soil. So far, stone-embedded devices to measure the movements have been quite big, up to several decimetres, which does not allow for the analysis of pebbles from medium and coarse gravel classes. In this study, we used a novel device called Smartstones, which is significantly smaller. The Smartstone device's dimensions are 55 mm in length, 8 mm in diameter and an approximately 70 mm long flexible antenna (device developer: SMART-RFID solutions Rheinberg, Germany). It is powered by two button cells, contains an own data storage and is able to wait inactive for longer times until it is activated by movement. It communicates via active RFID (radio frequency identification) technology to a Linux gateway, which stores the sensor data in a database after transmission and is able to handle several devices simultaneously. The device contains a Bosch sensor that measures magnetic flux density, acceleration and rotation, in each case for / around three axes. In our study, the device has been used in a laboratory flume (270 cm in length, 5° to 10° slope, approx. 2 cm water level, mean flow velocities between 0.66 and 1 ms-1) in combination with a high speed camera to capture the movement of the pebbles. The simultaneous usage of two capture devices allows for a comparison of the results: movement patterns derived from image analysis and sensor data analysis. In the device's first software version, all three sensors - acceleration, compass, and gyroscope - were active. The acquisition of all values resulted in a sampling rate of 10 Hz. After the experiments using this setup, the data analysis of the high speed images and the device's data showed that the pebble reached rotation velocities beyond 5 rotations per second, even on the relatively short flume and low water levels. Thus, the device produced only sub-Nyquist sampling values and the rotation velocity of the pebble could not be derived correctly using solely the device's data. Consequently, the device's software was adapted by the developers: the second (and current) version of the device only acquires acceleration and compass, as the acquisition of the gyroscope's value does not allow for higher sampling rates. The second version samples every 12 ms. All aforementioned experiments have been repeated using the adapted device. For data analysis, the high-speed camera images were merged with the device data using a MATLAB script. Furthermore, the derived relative pebble orientation - yaw, pitch and roll - is illustrated using a rotated CAD model of the pebble. The pebble's orientation is derived from compass and accelerometer data using sensor fusion and algorithms for tilt compensated compasses. The results show that the device is perfectly able to capture the movement of the pebble such as rotation (including the rotation axis), sliding or saltation. The interacting forces between the pebble and the underground can be calculated from the acceleration data. However, the accelerometer data also showed that the range of the sensor is not sufficiently large: clipping of values occurred. According to present instrument specifications, the sensor is able to capture up to 4 g for each axis but the resulting vectors for acceleration along all three axes showed values greater than 4 g, even up to the theoretical maximum of approximately 6.9 g. Thus, an impact of this strength that only stresses one axis cannot be measured. As a result of this clipping, the derivation of the pebble's absolute position using double integration of acceleration values is associated with flaws. Besides this clipping, the derived position will deviate from the true position for larger distances or longer experiment durations as the noise of the data will be integrated, too. Several requirements for the next device version were formulated: The range of the accelerometer will be set to the sensor's maximum of 16 g. The device w

  9. Exploring Magnetism on Earth

    NSDL National Science Digital Library

    2005-01-01

    This teacher's guide contains four lessons that provide a way for teachers to introduce students to and elaborate on Earth's changing magnetic field. It covers learning to navigate using Earth's magnetic field and compass, Earth's magnetic pole and its motion across Earth's surface, magnetic reversals on Earth, and Earth's currently declining magnetic field. These lessons have been taught primarily in math, geology, and astronomy classes.

  10. The installation and correction of compasses in airplanes

    NASA Technical Reports Server (NTRS)

    Schoeffel, M F

    1927-01-01

    The saving of time that results from flying across country on compass headings is beginning to be widely recognized. At the same time the general use of steel tube fuselages has made a knowledge of compass correction much more necessary than was the case when wooden fuselages were the rule. This paper has been prepared primarily for the benefit of the pilot who has never studied navigation and who does not desire to go into the subject more deeply than to be able to fly compass courses with confidence. It also contains material for the designer who wishes to install his compasses with the expectation that they may be accurately corrected.

  11. COMPASS: A general purpose computer aided scheduling tool

    NASA Technical Reports Server (NTRS)

    Mcmahon, Mary Beth; Fox, Barry; Culbert, Chris

    1991-01-01

    COMPASS is a generic scheduling system developed by McDonnell Douglas under the direction of the Software Technology Branch at JSC. COMPASS is intended to illustrate the latest advances in scheduling technology and provide a basis from which custom scheduling systems can be built. COMPASS was written in Ada to promote readability and to conform to potential NASA Space Station Freedom standards. COMPASS has some unique characteristics that distinguishes it from commercial products. These characteristics are discussed and used to illustrate some differences between scheduling tools.

  12. Probes for investigating the effect of magnetic field, field orientation, temperature and strain on the critical current density of anisotropic high-temperature superconducting

    E-print Network

    Hampshire, Damian

    Probes for investigating the effect of magnetic field, field orientation, temperature and strain on the critical current density of anisotropic high-temperature superconducting tapes in a split-pair 15 AIP Conf. Proc. 711, 612 (2004); 10.1063/1.1774621 A probe for investigating the effects

  13. JOURNAL DE PHYSIQUE Colloque Cl, supplkment au no 4, Tome 38, Avril 1977, page Cl-329 ORIENTED DRY PRESSING OF STRONTIUM FERRITE MAGNETS

    E-print Network

    Paris-Sud XI, Université de

    PRESSING OF STRONTIUM FERRITE MAGNETS S. KOBE, D. KOLAR and M. DROFENIK J. Stefan Institute and Faculty recommended to form a loose, free flow- ing ferrite powder is based on spray drying of manetiz- ed slurry [2 was to develop a simpler method of preparation of loose, free flowing ferrite powder with good orientability

  14. d-Orbital orientation in a dimer cobalt complex: link to magnetic properties?

    PubMed

    Deutsch, Maxime; Claiser, Nicolas; Gillet, Jean-Michel; Lecomte, Claude; Sakiyama, Hiroshi; Tone, Katsuya; Souhassou, Mohamed

    2011-08-01

    The experimental charge-density distribution of the dinuclear cobalt(II) complex [Co(2)(sym-hmp)(2)](BPh(4))(2)·2H(2)O·2C(3)H(6)O was determined at 100 K. When decreasing the temperature, the magnetic susceptibility of this complex deviates from Curie law because of anti-ferromagnetic exchange interactions, but the susceptibility increases sharply at low temperature (< 20 K). To explain this magnetic behaviour a tilt angle between the Co-atom environments was previously theoretically predicted. The structure and experimental charge density determined in this study show a tilt angle. The calculated value, based on the 100 K experimental d-orbital model, is in agreement with the theoretical one. PMID:21775811

  15. Changes of inclusion, texture and magnetic property of non-oriented Si steel treated by Ca alloy

    NASA Astrophysics Data System (ADS)

    Lv, X.; Zhang, F.; Chen, X.

    2015-04-01

    Based on the industrial production of non-oriented Si steel, Ca treatment by Ca alloy adding during the RH refining process was studied. The changes of inclusion, crystal texture and microstructure, and its effect on magnetic properties of final steel sheets were analyzed. The results showed that, in present work, Ca treatment can improve the texture proportion of {110} and {111} significantly, and the formation of MnS and AlN inclusions were restrained. Meanwhile, the recrystallization effects of hot rolled strip get bad and the fiber structure enhanced obviously. The grain size of finished steel sheets increased as the increase of Ca alloy adding amount quickly, and then decreased. Compared with the non-Ca treatment charge, the numbers of inclusions whose size below 1.0?m will decrease by 68.06%, 87.50% and 94.94%, the texture proportion of {110} and {111} was 30.3%, 39.1%, 17.6% and 2.8%, 5.5%, 20.6%, while the correspondent Ca alloy adding amount is 0.67 kg/t steel, 1.00 kg/t steel and 1.67 kg/t steel, respectively. In addition, the core loss gradually decreases to a stable level as the increasing of Ca added, and the magnetic induction decreases quickly after slow increasing, respectively. The optimal Ca treatment mode depends on the chemical compositions of steel grades.

  16. Estimating Orientation Using Magnetic and Inertial Sensors and Different Sensor Fusion Approaches: Accuracy Assessment in Manual and Locomotion Tasks

    PubMed Central

    Bergamini, Elena; Ligorio, Gabriele; Summa, Aurora; Vannozzi, Giuseppe; Cappozzo, Aurelio; Sabatini, Angelo Maria

    2014-01-01

    Magnetic and inertial measurement units are an emerging technology to obtain 3D orientation of body segments in human movement analysis. In this respect, sensor fusion is used to limit the drift errors resulting from the gyroscope data integration by exploiting accelerometer and magnetic aiding sensors. The present study aims at investigating the effectiveness of sensor fusion methods under different experimental conditions. Manual and locomotion tasks, differing in time duration, measurement volume, presence/absence of static phases, and out-of-plane movements, were performed by six subjects, and recorded by one unit located on the forearm or the lower trunk, respectively. Two sensor fusion methods, representative of the stochastic (Extended Kalman Filter) and complementary (Non-linear observer) filtering, were selected, and their accuracy was assessed in terms of attitude (pitch and roll angles) and heading (yaw angle) errors using stereophotogrammetric data as a reference. The sensor fusion approaches provided significantly more accurate results than gyroscope data integration. Accuracy improved mostly for heading and when the movement exhibited stationary phases, evenly distributed 3D rotations, it occurred in a small volume, and its duration was greater than approximately 20 s. These results were independent from the specific sensor fusion method used. Practice guidelines for improving the outcome accuracy are provided. PMID:25302810

  17. Estimating orientation using magnetic and inertial sensors and different sensor fusion approaches: accuracy assessment in manual and locomotion tasks.

    PubMed

    Bergamini, Elena; Ligorio, Gabriele; Summa, Aurora; Vannozzi, Giuseppe; Cappozzo, Aurelio; Sabatini, Angelo Maria

    2014-01-01

    Magnetic and inertial measurement units are an emerging technology to obtain 3D orientation of body segments in human movement analysis. In this respect, sensor fusion is used to limit the drift errors resulting from the gyroscope data integration by exploiting accelerometer and magnetic aiding sensors. The present study aims at investigating the effectiveness of sensor fusion methods under different experimental conditions. Manual and locomotion tasks, differing in time duration, measurement volume, presence/absence of static phases, and out-of-plane movements, were performed by six subjects, and recorded by one unit located on the forearm or the lower trunk, respectively. Two sensor fusion methods, representative of the stochastic (Extended Kalman Filter) and complementary (Non-linear observer) filtering, were selected, and their accuracy was assessed in terms of attitude (pitch and roll angles) and heading (yaw angle) errors using stereophotogrammetric data as a reference. The sensor fusion approaches provided significantly more accurate results than gyroscope data integration. Accuracy improved mostly for heading and when the movement exhibited stationary phases, evenly distributed 3D rotations, it occurred in a small volume, and its duration was greater than approximately 20 s. These results were independent from the specific sensor fusion method used. Practice guidelines for improving the outcome accuracy are provided. PMID:25302810

  18. Azimuthal asymmetries from unpolarized data at COMPASS

    E-print Network

    C. Schill; for the COMPASS collaboration

    2011-07-12

    The investigation of transverse spin and transverse momentum effects in the nucleon is one of the key physics programs of the COMPASS experiment at CERN. COMPASS investigates these effects scattering 160 GeV/c muons off a fixed NH3 or 6LiD target. The azimuthal asymmetries which appear in the cross-section of semi-inclusive deep-inelastic scattering on an unpolarized target have been measured. These asymmetries give insight into the intrinsic transverse momentum of the quarks in the nucleon by the Cahn effect and into a possible correlation between transverse momentum and transverse spin. New results for azimuthal asymmetries of single hadrons produced in scattering muons off an unpolarized 6LiD target are presented.

  19. Transverse Spin Effects in SIDIS at COMPASS

    SciTech Connect

    Joosten, Rainer [HISKP, University Bonn, Nussallee 14-16, 53115 Bonn (Germany)

    2009-12-17

    The measurement of single spin asymmetries in semi-inclusive deep-inelastic scattering (SIDIS) on a transversely polarized target is an important part of the COMPASS physics program. It allows us to investigate the transversity distribution functions as well as transverse momentum dependent distribution functions by measuring azimuthal asymmetries in the hadron production. After COMPASS took data in the years 2002-2004 by scattering a 160 GeV/c muon beam off a transversely polarized deuteron ({sup 6}LiD) target, in 2007 additional data was collected on a transversely polarized proton (NH{sub 3}) target. In this contribution, the latest results on the Collins and Sivers asymmetries in single hadron production as well as two-hadron asymmetries from the analysis of the proton data are presented and compared with existing model predictions.

  20. Proposal for GPD studies at COMPASS

    SciTech Connect

    Burtin, E. [CEA-Centre de Saclay Irfu, Service de Physique Nucleaire F-91191 Gif-sur Yvette Cedex (France)

    2011-10-24

    The study of nucleon structure through Generalised Parton Distributions (GPD) is one major part of the future COMPASS-II physics program and can be performed using exclusive reactions like Deeply Virtual Compton Scattering (DVCS) and Meson Production. The high energy of the muon beam allows to measure the x{sub B}-dependence of the t-slope of the DVCS cross section. The use of positive and negative polarised muon beams allows to determine the Beam Charge and Spin Difference of the DVCS cross sections to access the real part of the Compton form factor related to the dominant GPD H. The sensitivity of both measurements is examined and confronted to existing models or global fits of the data. Preliminary beam test data were analyzed and demonstrated the feasibility of the identification of the DVCS reaction using the COMPASS experimental set-up.

  1. Sivers effect at HERMES, COMPASS & CLAS12

    SciTech Connect

    Arnold, S.; V. Efremov, A.; Goeke, Klaus; Schlegel, Marc; Schweitzer, Peter

    2009-01-01

    Single spin asymmetries in semi-inclusive deep-inelastic scattering off transversely polarized targets give information on, among other fascinating effects, a pseudo time-reversal odd parton distribution function, the ?Sivers function?. In this proceeding we review the extractions of this function from HERMES and COMPASS data. In particular, the HERMES pion and kaon data suggest significant contributions from sea-quarks at x ? 0.15 to the Sivers effect. We present a new fit that includes all relevant sea quark distributions and gives a statistically satisfactory overall description of the data, but does not describe well the K+ data from HERMES. We argue that measurements of the pion- and kaon Sivers effect at CLAS12, and COMPASS, will clarify the situation.

  2. Triple GEM tracking detectors for COMPASS

    Microsoft Academic Search

    B. Ketzer; M. C. Altunbas; K. Dehmelt; J. Ehlers; J. Friedrich; B. Grube; S. Kappler; I. Konorov; S. Paul; A. Placci; L. Ropelewski; F. Sauli; L. Schmitt; F. Simon

    2002-01-01

    The small-area tracker of COMPASS, a high-luminosity fixed target experiment at CERN's SPS, includes a set of 20 large-size (31 × 31 cm2) gas electron multiplier (GEM) detectors. Based on gas amplification in three cascaded GEM foils, these devices permit to obtain high gain and good spatial resolution even at very high particle fluxes. A two-coordinate projective readout yields, for

  3. Tests of Chiral Perturbation Theory with COMPASS

    SciTech Connect

    Friedrich, Jan [Physik-Department, Technische Universitaet Muenchen (Germany)

    2010-12-28

    The COMPASS experiment at CERN studies with high precision pion-photon induced reactions on nuclear targets via the Primakoff effect. This offers the possibility to test chiral perturbation theory (ChPT) in various channels: Pion Compton scattering allows to clarify the longstanding question of the pion polarisabilities, single neutral pion production is related to the chiral anomaly, and for the two-pion production cross sections exist as yet untested ChPT predictions.

  4. Measurements of unpolarised azimuthal asymmetries at COMPASS

    E-print Network

    Giulio Sbrizzai; for the COMPASS Collaboration

    2009-02-03

    Azimuthal asymmetries in unpolarized SIDIS can be used to probe the transverse momentum of the quarks inside the nucleon. Furthermore they give access to the so-far unmeasured Boer-Mulders function. We report on the extraction of these asymmetries from the COMPASS data taken with a 160 GeV/c $\\mu ^+$ beam impinging on a deuteron target. This asymmetries have been extracted separately for positive and negative hadrons, and the results have been compared with theoretical predictions.

  5. Recent results from COMPASS muon scattering measurements

    SciTech Connect

    Capozza, Luigi [Irfu/SPhN - CEA Saclay, 91190 Gif-sur-Yvette (France); Collaboration: COMPASS Collaboration

    2012-10-23

    A sample of recent results in muon scattering measurements from the COMPASS experiment at CERN will be reviewed. These include high energy processes with longitudinally polarised proton and deuteron targets. High energy polarised measurements provide important constraints for studying the nucleon spin structure and thus permit to test the applicability of the theoretical framework of factorisation theorems and perturbative QCD. Specifically, latest results on longitudinal quark polarisation, quark helicity densities and gluon polarisation will be reviewed.

  6. Relative effect(s) of texture and grain size on magnetic properties in a low silicon non-grain oriented electrical steel

    NASA Astrophysics Data System (ADS)

    PremKumar, R.; Samajdar, I.; Viswanathan, N. N.; Singal, V.; Seshadri, V.

    2003-08-01

    Hot rolled low Si (silicon) non-grain oriented electrical steel was cold rolled to different reductions. Cold rolled material was subsequently recrystallized, 650°C and 2 h, and then temper rolled (to 7% reduction) for the final grain growth annealing and decarburization treatment at 850°C for 2-24 h. The development of texture, grain size and magnetic properties were characterized at different stages of processing. Effect of texture on magnetic properties (watt loss and permeability) was observed to be best represented by the ratio of volume fractions of (1 1 1)/(0 0 1) fibers, as estimated by convoluting X-ray ODFs (orientation distribution functions) with respective model functions. Such a ratio was termed as generalized texture factor (tf) for the non-grain oriented electrical steel. An effort was made to delink effects of grain size and texture, as represented by respective tf, on watt loss and permeability by careful analysis of experimental data. In general, low tf and/or high grain size were responsible for low watt loss and high permeability. However, individual effect of grain size or tf on magnetic properties was less significant at low tf or large grain size, respectively. An attempt was made to fit regression equations, namely—linear, exponential and power, relating magnetic properties with tf and grain size, limiting the fitting parameters to 3. Least standard deviations, between experimental and predicted values, were obtained by power regression equations for both magnetic properties.

  7. Robustness of the filamentation instability for asymmetric plasma shells collision in arbitrarily oriented magnetic field

    SciTech Connect

    Bret, A. [ETSI Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real, Spain and Instituto de Investigaciones Energticas y Aplicaciones Industriales, Campus Universitario de Ciudad Real, 13071 Ciudad Real (Spain)] [ETSI Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real, Spain and Instituto de Investigaciones Energticas y Aplicaciones Industriales, Campus Universitario de Ciudad Real, 13071 Ciudad Real (Spain)

    2013-10-15

    The filamentation instability triggered when two counter streaming plasma shells overlap appears to be the main mechanism by which collisionless shocks are generated. It has been known for long that a flow aligned magnetic field can completely suppress this instability. In a recent paper [Phys. Plasmas 18, 080706 (2011)], it was demonstrated in two dimensions that for the case of two cold, symmetric, relativistically colliding shells, such cancellation cannot occur if the field is not perfectly aligned. Here, this result is extended to the case of two asymmetric shells. The filamentation instability appears therefore as an increasingly robust mechanism to generate shocks.

  8. Anisotropy of magnetic susceptibility versus lattice- and shape-preferred orientation in the Lac Tio hemo-ilmenite ore body (Grenville province, Quebec)

    NASA Astrophysics Data System (ADS)

    Bolle, Olivier; Charlier, Bernard; Bascou, Jérôme; Diot, Hervé; McEnroe, Suzanne A.

    2014-08-01

    The Lac Tio hemo-ilmenite ore body crops out in the outer portion of the 1.06 Ga Lac Allard anorthosite, a member of the Havre-Saint-Pierre anorthosite suite from the Grenville province of North America. It is made up of ilmenitite (commonly with more than 95% hemo-ilmenite) associated with noritic lithologies and anorthosite. The present study compares the magnetic fabric of the ore body, as deduced from anisotropy of magnetic susceptibility (AMS) measurements, with the crystallographic and shape fabrics, obtained from lattice-preferred orientation (LPO) and shape-preferred orientation (SPO) measurements made using electron backscattered diffraction (EBSD) and 3D image analysis, respectively. Room-temperature hysteresis measurements, thermomagnetic curves and values of the bulk magnetic susceptibility reveal a magnetic mineralogy dominated by a mixed contribution of hemo-ilmenite and magnetite. The hemo-ilmenite grains display a LPO characterized by a strong preferred orientation of the basal (0001) plane of ilmenite along which hematite was exsolved. This LPO and the magnetic fabric fit well (angle between the crystallographic c-axis and the axis of minimum susceptibility ? ca. 15° for most samples), and the latter is thus strongly influenced by the hemo-ilmenite magneto-crystalline anisotropy. A magnetite SPO, concordant with the hemo-ilmenite LPO, may also influence and even dominate the magnetic fabric. The rock shape fabric is coaxial with the magnetic fabric that can thus be used to perform detailed structural mapping. Interpretation of the magnetic fabric and field structural data suggests that the Lac Tio ore body would be a sag point at the margin of the Lac Allard anorthosite, deformed by ballooning during the final stage of diapiric emplacement of the anorthosite body.

  9. Control of VLF burst activity in the nightside ionosphere of Venus by the magnetic field orientation

    NASA Technical Reports Server (NTRS)

    Ho, C.-M.; Strangeway, R. J.; Russell, C. T.

    1992-01-01

    A burst identificaton method developed by Ho et al. (1991) is used to analyze data on the nightside ionosphere of Venus in order to determine whether VLF bursts observed there are better interpreted as whistler mode waves or ion acoustic waves. The correlation between burst occurrence and the angle between the magnetic field and the radial direction, as well as the spacecraft flight direction are examined. Narrow-band 100-Hz bursts are found to be more frequently associated with radial magnetic fields while wideband signals are more frequently associated with horizontal fields. Under the assumption of vertical propagation, the normalized 100-Hz burst rate inside the resonance cone is larger than that outside. The burst rate inside the resonance cone dominates the altitude distribution. By assuming vertical propagation, the 100-Hz signals clearly divide into two populations. One is whistler mode propagating inside the resonance cone. The other is a nonpropagating mode outside the resonance cone which decreases quickly with altitude with a scale height of about 20 km.

  10. Tuning magnetic anisotropy in (001) oriented L1{sub 0} (Fe{sub 1-x}Cu{sub x}){sub 55}Pt{sub 45} films

    SciTech Connect

    Gilbert, Dustin A.; Liu, Kai [Physics Department, University of California, Davis, California 95616 (United States)] [Physics Department, University of California, Davis, California 95616 (United States); Wang, Liang-Wei; Lai, Chih-Huang [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan (China)] [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan (China); Klemmer, Timothy J.; Thiele, Jan-Ulrich [Seagate Technology, Fremont, California 94538 (United States)] [Seagate Technology, Fremont, California 94538 (United States)

    2013-04-01

    We have achieved (001) oriented L1{sub 0} (Fe{sub 1-x}Cu{sub x}){sub 55}Pt{sub 45} thin films, with magnetic anisotropy up to 3.6 Multiplication-Sign 10{sup 7} erg/cm{sup 3}, using atomic-scale multilayer sputtering and post annealing at 400 Degree-Sign C for 10 s. By fixing the Pt concentration, structure and magnetic properties are systematically tuned by the Cu addition. Increasing Cu content results in an increase in the tetragonal distortion of the L1{sub 0} phase, significant changes to the film microstructure, and lowering of the saturation magnetization and anisotropy. The relatively convenient synthesis conditions, along with the tunable magnetic properties, make such materials highly desirable for future magnetic recording technologies.

  11. Conformation of alamethicin in oriented phospholipid bilayers determined by (15)N solid-state nuclear magnetic resonance.

    PubMed Central

    Bak, M; Bywater, R P; Hohwy, M; Thomsen, J K; Adelhorst, K; Jakobsen, H J; Sørensen, O W; Nielsen, N C

    2001-01-01

    The conformation of the 20-residue antibiotic ionophore alamethicin in macroscopically oriented phospholipid bilayers has been studied using (15)N solid-state nuclear magnetic resonance (NMR) spectroscopy in combination with molecular modeling and molecular dynamics simulations. Differently (15)N-labeled variants of alamethicin and an analog with three of the alpha-amino-isobutyric acid residues replaced by alanines have been investigated to establish experimental structural constraints and determine the orientation of alamethicin in hydrated phospholipid (dimyristoylphosphatidylcholine) bilayers and to investigate the potential for a major kink in the region of the central Pro(14) residue. From the anisotropic (15)N chemical shifts and (1)H-(15)N dipolar couplings determined for alamethicin with (15)N-labeling on the Ala(6), Val(9), and Val(15) residues and incorporated into phospholipid bilayer with a peptide:lipid molar ratio of 1:8, we deduce that alamethicin has a largely linear alpha-helical structure spanning the membrane with the molecular axis tilted by 10-20 degrees relative to the bilayer normal. In particular, we find compatibility with a straight alpha-helix tilted by 17 degrees and a slightly kinked molecular dynamics structure tilted by 11 degrees relative to the bilayer normal. In contrast, the structural constraints derived by solid-state NMR appear not to be compatible with any of several model structures crossing the membrane with vanishing tilt angle or the earlier reported x-ray diffraction structure (Fox and Richards, Nature. 300:325-330, 1982). The solid-state NMR-compatible structures may support the formation of a left-handed and parallel multimeric ion channel. PMID:11509381

  12. Robustness of the filamentation instability as shock mediator in arbitrarily oriented magnetic field

    SciTech Connect

    Bret, A.; Alvaro, E. Perez [ETSI Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain) and Instituto de Investigaciones Energticas y Aplicaciones Industriales, Campus Universitario de Ciudad Real, 13071 Ciudad Real (Spain)

    2011-08-15

    The filamentation instability (sometimes also referred to as ''Weibel'') is a key process in many astrophysical scenario. In the Fireball model for gamma ray bursts, this instability is believed to mediate collisionless shock formation from the collision of two plasma shells. It has been known for long that a flow aligned magnetic field can completely cancel this instability. We show here that in the general case where there is an angle between the field and the flow, the filamentation instability can never be stabilized, regardless of the field strength. The presented model analyzes the stability of two symmetric counter-streaming cold electron/proton plasma shells. Relativistic effects are accounted for, and various exact analytical results are derived. This result guarantees the occurrence of the instability in realistic settings fulfilling the cold approximation.

  13. Mobile Robot Localization using an Electronic Compass for Corridor Environment

    E-print Network

    #12; #12; !"""# Mobile Robot Localization using an Electronic Compass for Corridor Environment S. Suksakulchai, S. Thongchai, D. M. Wilkes, and K. Kawamura Intelligent Robotics Laboratory- passes are often used to detect the heading of mo- bile robots. However, electronic compasses have one

  14. The Phenomenon of Compassion Fatigue in Perioperative Nursing

    Microsoft Academic Search

    Kendall Schwam

    1998-01-01

    Compassion fatigue is described as the emotional burden that health care providers may experience as a result of overexposure to a traumatic event that has befallen victims. Perioperative nurses are experiencing increased exposure to major traumatic events within their practice, especially those nurses who work in level I trauma centers. This article helps nurses identify risks for compassion fatigue and

  15. The Influence of Anger and Compassion on Negotiation Performance

    Microsoft Academic Search

    Keith G. Allred; John S. Mallozzi; Fusako Matsui; Christopher P. Raia

    1997-01-01

    We examined whether the discrete, other-directed emotions of anger and compassion exert a greater influence on negotiations than mood. Drawing on cognitive appraisal theories of emotion, we specifically tested whether negotiators who felt high anger and low compassion for each other would (1) have less desire to work with each other in the future, (2) achieve fewer joint gains, and

  16. Passivity Based Control Of The Compass Gait Biped

    Microsoft Academic Search

    Mark W. Spong

    1999-01-01

    . In this paper we discuss the passivity based control of the two-link robotknown as the Compass Gait Biped. Starting from a narrow region of initial conditions,the compass gait biped is capable of locomotion down shallow inclines without actuationor feedback control of any kind. We will discuss some feedback control strategiesthat can exploit these passive dynamics by shaping the energy

  17. Numerical investigations of plasma parameters in the COMPASS tokamak

    SciTech Connect

    Havlickova, E. [Charles University, Department of Surface and Plasma Science (Czech Republic); Zagorski, R. [EURATOM Association, Institute of Plasma Physics and Laser Microfusion (Poland); Panek, R. [Association EURATOM/IPP.CR, Institute of Plasma Physics (Czech Republic)

    2008-09-15

    A numerical investigation of plasma parameters in a diverter configuration of COMPASS tokamak is presented. The plasma parameters in the device are analyzed in the frame of the self-consistent description of the central plasma and edge region. The possibility of achieving high recycling and detached regimes in the boundary layer of the COMPASS tokamak is discussed.

  18. An Autonomous Agent Navigating with a Polarized Light Compass

    Microsoft Academic Search

    Dimitrios Lambrinos; Hiroshi Kobayashi; Rolf Pfeifer; Marinus Maris; Thomas Labhart; Rüdiger Wehner

    1997-01-01

    One of the fundamental abilities required in autonomous agents is homing. Natural agents—for instance, desert ants—solve the homing problem mainly by using path integration within an egocentric frame of reference. When employing such a mechanism, compass information for determining direction is necessary, and the precision of the compass will have a crucial effect on the precision of homing. For deriving

  19. St. Pi Day construction with a compass & ruler

    NSDL National Science Digital Library

    Cheryl Gaynr

    2012-07-26

    St. Pi Day construction with compass This activity uses a compass and straight-edge(ruler) to construct a design. The design is then used to complete a worksheet involving perimeter, circumference, area and dimensional changes which affect the scale factor ratio.

  20. Control of the Compass Gait on Rough Terrain

    E-print Network

    Tedrake, Russ

    Essential model for dynamic walking on rough terrain: · Hip-actuated compass gait (CG) with leg inertia Essential model for dynamic walking on rough terrain: · Hip-actuated compass gait (CG) with leg inertia masses at hip (mh) and on each leg (m) ; · Passive pivot model for "toe" of stance leg · 5 States