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Sample records for magnetic compass orientation

  1. Magnetic compass orientation in the European eel.

    PubMed

    Durif, Caroline M F; Browman, Howard I; Phillips, John B; Skiftesvik, Anne Berit; Vøllestad, L Asbjørn; Stockhausen, Hans H

    2013-01-01

    European eel migrate from freshwater or coastal habitats throughout Europe to their spawning grounds in the Sargasso Sea. However, their route (~ 6000 km) and orientation mechanisms are unknown. Several attempts have been made to prove the existence of magnetoreception in Anguilla sp., but none of these studies have demonstrated magnetic compass orientation in earth-strength magnetic field intensities. We tested eels in four altered magnetic field conditions where magnetic North was set at geographic North, South, East, or West. Eels oriented in a manner that was related to the tank in which they were housed before the test. At lower temperature (under 12°C), their orientation relative to magnetic North corresponded to the direction of their displacement from the holding tank. At higher temperatures (12-17°C), eels showed bimodal orientation along an axis perpendicular to the axis of their displacement. These temperature-related shifts in orientation may be linked to the changes in behavior that occur between the warm season (during which eels are foraging) and the colder fall and winter (during which eels undertake their migrations). These observations support the conclusion that 1. eels have a magnetic compass, and 2. they use this sense to orient in a direction that they have registered moments before they are displaced. The adaptive advantage of having a magnetic compass and learning the direction in which they have been displaced becomes clear when set in the context of the eel's seaward migration. For example, if their migration is halted or blocked, as it is the case when environmental conditions become unfavorable or when they encounter a barrier, eels would be able to resume their movements along their old bearing when conditions become favorable again or when they pass by the barrier.

  2. Magnetic Compass Orientation in the European Eel

    PubMed Central

    Durif, Caroline M. F.; Browman, Howard I.; Phillips, John B.; Skiftesvik, Anne Berit; Vøllestad, L. Asbjørn; Stockhausen, Hans H.

    2013-01-01

    European eel migrate from freshwater or coastal habitats throughout Europe to their spawning grounds in the Sargasso Sea. However, their route (∼ 6000 km) and orientation mechanisms are unknown. Several attempts have been made to prove the existence of magnetoreception in Anguilla sp., but none of these studies have demonstrated magnetic compass orientation in earth-strength magnetic field intensities. We tested eels in four altered magnetic field conditions where magnetic North was set at geographic North, South, East, or West. Eels oriented in a manner that was related to the tank in which they were housed before the test. At lower temperature (under 12°C), their orientation relative to magnetic North corresponded to the direction of their displacement from the holding tank. At higher temperatures (12–17°C), eels showed bimodal orientation along an axis perpendicular to the axis of their displacement. These temperature-related shifts in orientation may be linked to the changes in behavior that occur between the warm season (during which eels are foraging) and the colder fall and winter (during which eels undertake their migrations). These observations support the conclusion that 1. eels have a magnetic compass, and 2. they use this sense to orient in a direction that they have registered moments before they are displaced. The adaptive advantage of having a magnetic compass and learning the direction in which they have been displaced becomes clear when set in the context of the eel’s seaward migration. For example, if their migration is halted or blocked, as it is the case when environmental conditions become unfavorable or when they encounter a barrier, eels would be able to resume their movements along their old bearing when conditions become favorable again or when they pass by the barrier. PMID:23554997

  3. Magnetic compass orientation in the European eel.

    PubMed

    Durif, Caroline M F; Browman, Howard I; Phillips, John B; Skiftesvik, Anne Berit; Vøllestad, L Asbjørn; Stockhausen, Hans H

    2013-01-01

    European eel migrate from freshwater or coastal habitats throughout Europe to their spawning grounds in the Sargasso Sea. However, their route (~ 6000 km) and orientation mechanisms are unknown. Several attempts have been made to prove the existence of magnetoreception in Anguilla sp., but none of these studies have demonstrated magnetic compass orientation in earth-strength magnetic field intensities. We tested eels in four altered magnetic field conditions where magnetic North was set at geographic North, South, East, or West. Eels oriented in a manner that was related to the tank in which they were housed before the test. At lower temperature (under 12°C), their orientation relative to magnetic North corresponded to the direction of their displacement from the holding tank. At higher temperatures (12-17°C), eels showed bimodal orientation along an axis perpendicular to the axis of their displacement. These temperature-related shifts in orientation may be linked to the changes in behavior that occur between the warm season (during which eels are foraging) and the colder fall and winter (during which eels undertake their migrations). These observations support the conclusion that 1. eels have a magnetic compass, and 2. they use this sense to orient in a direction that they have registered moments before they are displaced. The adaptive advantage of having a magnetic compass and learning the direction in which they have been displaced becomes clear when set in the context of the eel's seaward migration. For example, if their migration is halted or blocked, as it is the case when environmental conditions become unfavorable or when they encounter a barrier, eels would be able to resume their movements along their old bearing when conditions become favorable again or when they pass by the barrier. PMID:23554997

  4. 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.

  5. Magnetic compass orientation in birds and its physiological basis

    NASA Astrophysics Data System (ADS)

    Wiltschko, Wolfgang; Wiltschko, Roswitha

    2002-09-01

    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 and pre-exposure to specific wavelengths caused changes in behavior. The behavioral data indicate a complex relationship between the wavelength of light and magnetoreception, suggesting the involvement of more than one type of receptors. Extracellular recordings from the nucleus of the basal optic root and the tectum opticum identified units that responded to changes in magnetic North. Each unit showed a peak in a distinct spatial direction, so that the input of these units, processed collectively and integrated, would indicate compass directions.

  6. A visual pathway links brain structures active during magnetic compass orientation in migratory birds.

    PubMed

    Heyers, Dominik; Manns, Martina; Luksch, Harald; Güntürkün, Onur; Mouritsen, Henrik

    2007-09-26

    The magnetic compass of migratory birds has been suggested to be light-dependent. Retinal cryptochrome-expressing neurons and a forebrain region, "Cluster N", show high neuronal activity when night-migratory songbirds perform magnetic compass orientation. By combining neuronal tracing with behavioral experiments leading to sensory-driven gene expression of the neuronal activity marker ZENK during magnetic compass orientation, we demonstrate a functional neuronal connection between the retinal neurons and Cluster N via the visual thalamus. Thus, the two areas of the central nervous system being most active during magnetic compass orientation are part of an ascending visual processing stream, the thalamofugal pathway. Furthermore, Cluster N seems to be a specialized part of the visual wulst. These findings strongly support the hypothesis that migratory birds use their visual system to perceive the reference compass direction of the geomagnetic field and that migratory birds "see" the reference compass direction provided by the geomagnetic field.

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

    PubMed

    Oliveriusová, Ludmila; Němec, Pavel; Pavelková, Zuzana; Sedláček, 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

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

    NASA Astrophysics Data System (ADS)

    Oliveriusová, Ludmila; Němec, Pavel; Pavelková, Zuzana; Sedláček, 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.

  9. Polarized light modulates light-dependent magnetic compass orientation in birds

    PubMed Central

    Muheim, Rachel; Sjöberg, Sissel; Pinzon-Rodriguez, Atticus

    2016-01-01

    Magnetoreception of the light-dependent magnetic compass in birds is suggested to be mediated by a radical-pair mechanism taking place in the avian retina. Biophysical models on magnetic field effects on radical pairs generally assume that the light activating the magnetoreceptor molecules is nondirectional and unpolarized, and that light absorption is isotropic. However, natural skylight enters the avian retina unidirectionally, through the cornea and the lens, and is often partially polarized. In addition, cryptochromes, the putative magnetoreceptor molecules, absorb light anisotropically, i.e., they preferentially absorb light of a specific direction and polarization, implying that the light-dependent magnetic compass is intrinsically polarization sensitive. To test putative interactions between the avian magnetic compass and polarized light, we developed a spatial orientation assay and trained zebra finches to magnetic and/or overhead polarized light cues in a four-arm “plus” maze. The birds did not use overhead polarized light near the zenith for sky compass orientation. Instead, overhead polarized light modulated light-dependent magnetic compass orientation, i.e., how the birds perceive the magnetic field. Birds were well oriented when tested with the polarized light axis aligned parallel to the magnetic field. When the polarized light axis was aligned perpendicular to the magnetic field, the birds became disoriented. These findings are the first behavioral evidence to our knowledge for a direct interaction between polarized light and the light-dependent magnetic compass in an animal. They reveal a fundamentally new property of the radical pair-based magnetoreceptor with key implications for how birds and other animals perceive the Earth’s magnetic field. PMID:26811473

  10. Polarized light modulates light-dependent magnetic compass orientation in birds.

    PubMed

    Muheim, Rachel; Sjöberg, Sissel; Pinzon-Rodriguez, Atticus

    2016-02-01

    Magnetoreception of the light-dependent magnetic compass in birds is suggested to be mediated by a radical-pair mechanism taking place in the avian retina. Biophysical models on magnetic field effects on radical pairs generally assume that the light activating the magnetoreceptor molecules is nondirectional and unpolarized, and that light absorption is isotropic. However, natural skylight enters the avian retina unidirectionally, through the cornea and the lens, and is often partially polarized. In addition, cryptochromes, the putative magnetoreceptor molecules, absorb light anisotropically, i.e., they preferentially absorb light of a specific direction and polarization, implying that the light-dependent magnetic compass is intrinsically polarization sensitive. To test putative interactions between the avian magnetic compass and polarized light, we developed a spatial orientation assay and trained zebra finches to magnetic and/or overhead polarized light cues in a four-arm "plus" maze. The birds did not use overhead polarized light near the zenith for sky compass orientation. Instead, overhead polarized light modulated light-dependent magnetic compass orientation, i.e., how the birds perceive the magnetic field. Birds were well oriented when tested with the polarized light axis aligned parallel to the magnetic field. When the polarized light axis was aligned perpendicular to the magnetic field, the birds became disoriented. These findings are the first behavioral evidence to our knowledge for a direct interaction between polarized light and the light-dependent magnetic compass in an animal. They reveal a fundamentally new property of the radical pair-based magnetoreceptor with key implications for how birds and other animals perceive the Earth's magnetic field. PMID:26811473

  11. Polarized light modulates light-dependent magnetic compass orientation in birds.

    PubMed

    Muheim, Rachel; Sjöberg, Sissel; Pinzon-Rodriguez, Atticus

    2016-02-01

    Magnetoreception of the light-dependent magnetic compass in birds is suggested to be mediated by a radical-pair mechanism taking place in the avian retina. Biophysical models on magnetic field effects on radical pairs generally assume that the light activating the magnetoreceptor molecules is nondirectional and unpolarized, and that light absorption is isotropic. However, natural skylight enters the avian retina unidirectionally, through the cornea and the lens, and is often partially polarized. In addition, cryptochromes, the putative magnetoreceptor molecules, absorb light anisotropically, i.e., they preferentially absorb light of a specific direction and polarization, implying that the light-dependent magnetic compass is intrinsically polarization sensitive. To test putative interactions between the avian magnetic compass and polarized light, we developed a spatial orientation assay and trained zebra finches to magnetic and/or overhead polarized light cues in a four-arm "plus" maze. The birds did not use overhead polarized light near the zenith for sky compass orientation. Instead, overhead polarized light modulated light-dependent magnetic compass orientation, i.e., how the birds perceive the magnetic field. Birds were well oriented when tested with the polarized light axis aligned parallel to the magnetic field. When the polarized light axis was aligned perpendicular to the magnetic field, the birds became disoriented. These findings are the first behavioral evidence to our knowledge for a direct interaction between polarized light and the light-dependent magnetic compass in an animal. They reveal a fundamentally new property of the radical pair-based magnetoreceptor with key implications for how birds and other animals perceive the Earth's magnetic field.

  12. Evidence of light-dependent magnetic compass orientation in urodele amphibian larvae.

    PubMed

    Diego-Rasilla, Francisco J; Luengo, Rosa M; Phillips, John B

    2015-09-01

    Experiments were conducted to investigate whether larval palmate newts undertake orientation toward or away from the home shoreline (y-axis orientation) using the geomagnetic field to steer the most direct route, and if they accomplish this task through a light-dependent magnetoreception mechanism similar to that found in anuran tadpoles and adult newts. Larval palmate newts trained and then tested under full-spectrum light showed bimodal magnetic compass orientation that coincided with the magnetic direction of the trained y-axis. In contrast, larvae trained under long-wavelength (≥500nm) light and then tested under full-spectrum light displayed bimodal orientation perpendicular to the trained y-axis direction. These results offer evidence for the use of magnetic compass cues in orienting urodele amphibian larvae, and provide additional support for the light-dependent magnetoreception mechanism since they are in complete agreement with earlier studies showing that the observed 90° shift in the direction of magnetic compass orientation under long-wavelength light (≥500nm) is due to a direct effect of light on the underlying magnetoreception mechanism. This study is the first to provide evidence of a light-dependent magnetic compass in larval urodeles. PMID:25981491

  13. Evidence of light-dependent magnetic compass orientation in urodele amphibian larvae.

    PubMed

    Diego-Rasilla, Francisco J; Luengo, Rosa M; Phillips, John B

    2015-09-01

    Experiments were conducted to investigate whether larval palmate newts undertake orientation toward or away from the home shoreline (y-axis orientation) using the geomagnetic field to steer the most direct route, and if they accomplish this task through a light-dependent magnetoreception mechanism similar to that found in anuran tadpoles and adult newts. Larval palmate newts trained and then tested under full-spectrum light showed bimodal magnetic compass orientation that coincided with the magnetic direction of the trained y-axis. In contrast, larvae trained under long-wavelength (≥500nm) light and then tested under full-spectrum light displayed bimodal orientation perpendicular to the trained y-axis direction. These results offer evidence for the use of magnetic compass cues in orienting urodele amphibian larvae, and provide additional support for the light-dependent magnetoreception mechanism since they are in complete agreement with earlier studies showing that the observed 90° shift in the direction of magnetic compass orientation under long-wavelength light (≥500nm) is due to a direct effect of light on the underlying magnetoreception mechanism. This study is the first to provide evidence of a light-dependent magnetic compass in larval urodeles.

  14. 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...

  15. Learned magnetic compass orientation by the Siberian hamster, Phodopus sungorus

    SciTech Connect

    Deutschlander, Mark E.; Freake, Michael J.; Borland, Christopher; Phillips, John B.; Madden, R C.; Anderson, Larry E.; Wilson, B W.

    2003-04-01

    Magnetic orientation has been demonstrated in Siberian hamsters, Phodopus sungorus. The behavior, using a nest building assay, shows a directional preference in nest position and appears in this animal to be a learned behavior. Hamsters were housed prior to testing in rectangular cages aligned along perpendicular axes. When subsequently tested in a radially-symmetrical arena, the hamsters positioned their nests in a bimodal distribution that coincided with the magnetic direction of the long-axis of the holding cages. In addition, results are presented that illustrate some of the factors that can influence behavioral responses to the magnetic field. In particular for P. sungorus, holding conditions prior to testing and the presence of non-magnetic cues may influence the strength and expression of magnetic orientation. Failure to consider these and other factors may help to explain why previous attempts to demonstrate magnetic orientation in a number of rodent species have failed or, when positive results have been obtained, have been difficult to replicate in other laboratories.

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

    PubMed

    Phillips, J B

    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 north-south or east-west axis. Tests were carried out in an enclosed indoor arena. Newts were tested in four horizontal alignments of the magnetic field: the ambient magnetic field (magnetic north at North) and three altered fields (magnetic north rotated to East, South or West). Data were analyzed after pooling the magnetic bearings from all four conditions in such a way as to retain the component of the newts' orientation that was a consistent response to the magnetic field. Elevation of training tank water temperature was used to increase the newts' motivation to orient in the direction of shore. Newts exposed to a training tank water temperature of 33-34 degrees C just prior to testing exhibited consistent unimodal magnetic compass orientation. The direction of orientation was altered predictably by changing training tank alignment and location relative to the laboratory building. The results provide the first evidence of a strong, replicable magnetic compass response in a terrestrial vertebrate under controlled laboratory conditions. Further, the present study demonstrates that the Eastern newt is able to learn a directional response relative to the earth's magnetic field.

  17. 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

  18. 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.

  19. 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.

  20. Light-dependent magnetic compass orientation in amphibians and insects: candidate receptors and candidate molecular mechanisms

    PubMed Central

    Phillips, John B.; Jorge, Paulo E.; Muheim, Rachel

    2010-01-01

    Magnetic compass orientation by amphibians, and some insects, is mediated by a light-dependent magnetoreception mechanism. Cryptochrome photopigments, best known for their role in circadian rhythms, are proposed to mediate such responses. In this paper, we explore light-dependent properties of magnetic sensing at three levels: (i) behavioural (wavelength-dependent effects of light on magnetic compass orientation), (ii) physiological (photoreceptors/photopigment systems with properties suggesting a role in magnetoreception), and (iii) molecular (cryptochrome-based and non-cryptochrome-based signalling pathways that are compatible with behavioural responses). Our goal is to identify photoreceptors and signalling pathways that are likely to play a specialized role in magnetoreception in order to definitively answer the question of whether the effects of light on magnetic compass orientation are mediated by a light-dependent magnetoreception mechanism, or instead are due to input from a non-light-dependent (e.g. magnetite-based) magnetoreception mechanism that secondarily interacts with other light-dependent processes. PMID:20124357

  1. 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

  2. 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

  3. Magnetic orientation in birds: non-compass responses under monochromatic light of increased intensity.

    PubMed Central

    Wiltschko, Wolfgang; Munro, Ursula; Ford, Hugh; Wiltschko, Roswitha

    2003-01-01

    Migratory Australian silvereyes (Zosterops lateralis) were tested under monochromatic light at wavelengths of 424 nm blue and 565 nm green. At a low light level of 7 x 10(15) quanta m(-2) s(-1) in the local geomagnetic field, the birds preferred their seasonally appropriate southern migratory direction under both wavelengths. Their reversal of headings when the vertical component of the magnetic field was inverted indicated normal use of the avian inclination compass. A higher light intensity of 43 x 10(15) quanta m(-2) s(-1), however, caused a fundamental change in behaviour: under bright blue, the silvereyes showed an axial tendency along the east-west axis; under bright green, they showed a unimodal preference of a west-northwesterly direction that followed a shift in magnetic north, but was not reversed by inverting the vertical component of the magnetic field. Hence it is not based on the inclination compass. The change in behaviour at higher light intensities suggests a complex interaction between at least two receptors. The polar nature of the response under bright green cannot be explained by the current models of light-dependent magnetoreception and will lead to new considerations on these receptive processes. PMID:14561276

  4. Magnetic orientation in birds: non-compass responses under monochromatic light of increased intensity.

    PubMed

    Wiltschko, Wolfgang; Munro, Ursula; Ford, Hugh; Wiltschko, Roswitha

    2003-10-22

    Migratory Australian silvereyes (Zosterops lateralis) were tested under monochromatic light at wavelengths of 424 nm blue and 565 nm green. At a low light level of 7 x 10(15) quanta m(-2) s(-1) in the local geomagnetic field, the birds preferred their seasonally appropriate southern migratory direction under both wavelengths. Their reversal of headings when the vertical component of the magnetic field was inverted indicated normal use of the avian inclination compass. A higher light intensity of 43 x 10(15) quanta m(-2) s(-1), however, caused a fundamental change in behaviour: under bright blue, the silvereyes showed an axial tendency along the east-west axis; under bright green, they showed a unimodal preference of a west-northwesterly direction that followed a shift in magnetic north, but was not reversed by inverting the vertical component of the magnetic field. Hence it is not based on the inclination compass. The change in behaviour at higher light intensities suggests a complex interaction between at least two receptors. The polar nature of the response under bright green cannot be explained by the current models of light-dependent magnetoreception and will lead to new considerations on these receptive processes. PMID:14561276

  5. Ontogenetic development of magnetic compass orientation in domestic chickens (Gallus gallus).

    PubMed

    Denzau, Susanne; Nießner, Christine; Rogers, Lesley J; Wiltschko, Wolfgang

    2013-08-15

    Domestic chickens (Gallus gallus) can be trained to search for a social stimulus in a specific magnetic direction, and cryptochrome 1a, found in the retina, has been proposed as a receptor molecule mediating magnetic directions. The present study combines immuno-histochemical and behavioural data to analyse the ontogenetic development of this ability. Newly hatched chicks already have a small amount of cryptochrome 1a in their violet cones; on day 5, the amount of cryptochrome 1a reached the same level as in adult chickens, suggesting that the physical basis for magnetoreception is present. In behavioural tests, however, young chicks 5 to 7 days old failed to show a preference of the training direction; on days 8, 9 and 12, they could be successfully trained to search along a specific magnetic axis. Trained and tested again 1 week later, the chicks that had not shown a directional preference on days 5 to 7 continued to search randomly, while the chicks tested from day 8 onward preferred the correct magnetic axis when tested 1 week later. The observation that the magnetic compass is not functional before day 8 suggests that certain maturation processes in the magnetosensitive system in the brain are not yet complete before that day. The reasons why chicks that have been trained before that day fail to learn the task later remain unclear.

  6. Ontogenetic development of magnetic compass orientation in domestic chickens (Gallus gallus).

    PubMed

    Denzau, Susanne; Nießner, Christine; Rogers, Lesley J; Wiltschko, Wolfgang

    2013-08-15

    Domestic chickens (Gallus gallus) can be trained to search for a social stimulus in a specific magnetic direction, and cryptochrome 1a, found in the retina, has been proposed as a receptor molecule mediating magnetic directions. The present study combines immuno-histochemical and behavioural data to analyse the ontogenetic development of this ability. Newly hatched chicks already have a small amount of cryptochrome 1a in their violet cones; on day 5, the amount of cryptochrome 1a reached the same level as in adult chickens, suggesting that the physical basis for magnetoreception is present. In behavioural tests, however, young chicks 5 to 7 days old failed to show a preference of the training direction; on days 8, 9 and 12, they could be successfully trained to search along a specific magnetic axis. Trained and tested again 1 week later, the chicks that had not shown a directional preference on days 5 to 7 continued to search randomly, while the chicks tested from day 8 onward preferred the correct magnetic axis when tested 1 week later. The observation that the magnetic compass is not functional before day 8 suggests that certain maturation processes in the magnetosensitive system in the brain are not yet complete before that day. The reasons why chicks that have been trained before that day fail to learn the task later remain unclear. PMID:23661773

  7. How Things Work: A Magnetic Compass with No Moving Parts.

    ERIC Educational Resources Information Center

    Crane, H. Richard

    1988-01-01

    Introduced is a magnetic compass with no moving parts. Presented are the principles of the compass and the method to make the compass. Shows a lodestone compass which is the most primitive compass form. (YP)

  8. Weak Broadband Electromagnetic Fields are More Disruptive to Magnetic Compass Orientation in a Night-Migratory Songbird (Erithacus rubecula) than Strong Narrow-Band Fields.

    PubMed

    Schwarze, Susanne; Schneider, Nils-Lasse; Reichl, Thomas; Dreyer, David; Lefeldt, Nele; Engels, Svenja; Baker, Neville; Hore, P J; Mouritsen, Henrik

    2016-01-01

    Magnetic compass orientation in night-migratory songbirds is embedded in the visual system and seems to be based on a light-dependent radical pair mechanism. Recent findings suggest that both broadband electromagnetic fields ranging from ~2 kHz to ~9 MHz and narrow-band fields at the so-called Larmor frequency for a free electron in the Earth's magnetic field can disrupt this mechanism. However, due to local magnetic fields generated by nuclear spins, effects specific to the Larmor frequency are difficult to understand considering that the primary sensory molecule should be organic and probably a protein. We therefore constructed a purpose-built laboratory and tested the orientation capabilities of European robins in an electromagnetically silent environment, under the specific influence of four different oscillating narrow-band electromagnetic fields, at the Larmor frequency, double the Larmor frequency, 1.315 MHz or 50 Hz, and in the presence of broadband electromagnetic noise covering the range from ~2 kHz to ~9 MHz. Our results indicated that the magnetic compass orientation of European robins could not be disrupted by any of the relatively strong narrow-band electromagnetic fields employed here, but that the weak broadband field very efficiently disrupted their orientation. PMID:27047356

  9. Weak Broadband Electromagnetic Fields are More Disruptive to Magnetic Compass Orientation in a Night-Migratory Songbird (Erithacus rubecula) than Strong Narrow-Band Fields

    PubMed Central

    Schwarze, Susanne; Schneider, Nils-Lasse; Reichl, Thomas; Dreyer, David; Lefeldt, Nele; Engels, Svenja; Baker, Neville; Hore, P. J.; Mouritsen, Henrik

    2016-01-01

    Magnetic compass orientation in night-migratory songbirds is embedded in the visual system and seems to be based on a light-dependent radical pair mechanism. Recent findings suggest that both broadband electromagnetic fields ranging from ~2 kHz to ~9 MHz and narrow-band fields at the so-called Larmor frequency for a free electron in the Earth’s magnetic field can disrupt this mechanism. However, due to local magnetic fields generated by nuclear spins, effects specific to the Larmor frequency are difficult to understand considering that the primary sensory molecule should be organic and probably a protein. We therefore constructed a purpose-built laboratory and tested the orientation capabilities of European robins in an electromagnetically silent environment, under the specific influence of four different oscillating narrow-band electromagnetic fields, at the Larmor frequency, double the Larmor frequency, 1.315 MHz or 50 Hz, and in the presence of broadband electromagnetic noise covering the range from ~2 kHz to ~9 MHz. Our results indicated that the magnetic compass orientation of European robins could not be disrupted by any of the relatively strong narrow-band electromagnetic fields employed here, but that the weak broadband field very efficiently disrupted their orientation. PMID:27047356

  10. Exploring Magnetic Fields with a Compass

    ERIC Educational Resources Information Center

    Lunk, Brandon; Beichner, Robert

    2011-01-01

    A compass is an excellent classroom tool for the exploration of magnetic fields. Any student can tell you that a compass is used to determine which direction is north, but when paired with some basic trigonometry, the compass can be used to actually measure the strength of the magnetic field due to a nearby magnet or current-carrying wire. In this…

  11. 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).

  12. Orientation in birds. The sun compass.

    PubMed

    Schmidt-Koenig, K; Ganzhorn, J U; Ranvaud, R

    1991-01-01

    The sun compass was discovered by G. Kramer in caged birds showing migratory restlessness. Subsequent experiments with caged birds employing directional training and clock shifts, carried out by Hoffman and Schmidt-Koenig, showed that the sun azimuth is used, and the sun altitude ignored. In the laboratory, McDonald found the accuracy to be +/- 3 degrees(-)+/- 5 degrees. According to Hoffmann and Schmidt-Koenig, caged birds trained at medium northern latitudes were able to allow for the sun's apparent movement north of the arctic circle, but not in equatorial and trans-equatorial latitudes. In homing experiments, and employing clock shifts, Schmidt-Koenig demonstrated that the sun compass is used by homing pigeons during initial orientation. This finding is the principal evidence for the existence of a map-and-compass navigational system. Pigeons living in equatorial latitudes utilize the sun compass even under the extreme solar conditions of equinox, achieving angular resolution of about 3 degrees in homing experiments. According to preliminary analyses, the homing pigeons' ephemerides are retarded by several weeks (Ranvaud, Schmidt-Koenig, Ganzhorn et al.).

  13. Newts: sun-compass orientation.

    PubMed

    Landreth, H F; Ferguson, D E

    1967-12-15

    Rough-skinned newts, captured from breeding ponds, oriented on courses that would have intersected the familiar shorelines at right angles, when released in a circular arena on land under the sun or moon. Pondward migrants oriented similarly. Reorientation failed under complete cloud cover and after 7 days of darkness in an environmental chamber, but persisted in newts whose eyes were excised and in those displaced more than 27 kilometers in darkness. Both normal and blind animals compensated for displacement in sunshine. Preliminary evidence suggests that alternative light receptors in blinded animals may be associated with the optic tectum. No evidence of olfactory guidance was observed. PMID:6058684

  14. The magnetic compass of domestic chickens.

    PubMed

    Denzau, Susanne; Nießner, Christine; Rogers, Lesley J; Wiltschko, Wolfgang

    2013-11-01

    In a recent paper, we showed that domestic chickens can be trained to search for a social stimulus in specific magnetic directions. Chickens can hardly fly and have only small home ranges, hence their having a functional magnetic compass may seem rather surprising. Yet considering the natural habitat of their ancestors and their lifestyle until recently, the advantages of a magnetic compass become evident. PMID:24753787

  15. Exploring Magnetic Fields with a Compass

    NASA Astrophysics Data System (ADS)

    Lunk, Brandon; Beichner, Robert

    2011-01-01

    A compass is an excellent classroom tool for the exploration of magnetic fields. Any student can tell you that a compass is used to determine which direction is north, but when paired with some basic trigonometry, the compass can be used to actually measure the strength of the magnetic field due to a nearby magnet or current-carrying wire. In this paper, we present a series of simple activities adapted from the Matter & Interactions textbook for doing just this. Interestingly, these simple measurements are comparable to predictions made by the Bohr model of the atom. Although antiquated, Bohr's atom can lead the way to a deeper analysis of the atomic properties of magnets. Although originally developed for an introductory calculus-based course, these activities can easily be adapted for use in an algebra-based class or even at the high school level.

  16. 46 CFR 167.40-45 - Magnetic compass and gyrocompass.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Magnetic compass and gyrocompass. 167.40-45 Section 167... NAUTICAL SCHOOL SHIPS Certain Equipment Requirements § 167.40-45 Magnetic compass and gyrocompass. (a) All mechanically propelled vessels in ocean or coastwise service must be fitted with a magnetic compass. (b)...

  17. 46 CFR 108.715 - Magnetic compass and gyrocompass.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Magnetic compass and gyrocompass. 108.715 Section 108... DESIGN AND EQUIPMENT Miscellaneous Equipment § 108.715 Magnetic compass and gyrocompass. (a) Each self-propelled unit in ocean or coastwise service must have a magnetic compass. (b) Each self-propelled unit of...

  18. 46 CFR 108.715 - Magnetic compass and gyrocompass.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Magnetic compass and gyrocompass. 108.715 Section 108... DESIGN AND EQUIPMENT Miscellaneous Equipment § 108.715 Magnetic compass and gyrocompass. (a) Each self-propelled unit in ocean or coastwise service must have a magnetic compass. (b) Each self-propelled unit of...

  19. 46 CFR 167.40-45 - Magnetic compass and gyrocompass.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Magnetic compass and gyrocompass. 167.40-45 Section 167... NAUTICAL SCHOOL SHIPS Certain Equipment Requirements § 167.40-45 Magnetic compass and gyrocompass. (a) All mechanically propelled vessels in ocean or coastwise service must be fitted with a magnetic compass. (b)...

  20. 46 CFR 167.40-45 - Magnetic compass and gyrocompass.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Magnetic compass and gyrocompass. 167.40-45 Section 167... NAUTICAL SCHOOL SHIPS Certain Equipment Requirements § 167.40-45 Magnetic compass and gyrocompass. (a) All mechanically propelled vessels in ocean or coastwise service must be fitted with a magnetic compass. (b)...

  1. 46 CFR 167.40-45 - Magnetic compass and gyrocompass.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Magnetic compass and gyrocompass. 167.40-45 Section 167... NAUTICAL SCHOOL SHIPS Certain Equipment Requirements § 167.40-45 Magnetic compass and gyrocompass. (a) All mechanically propelled vessels in ocean or coastwise service must be fitted with a magnetic compass. (b)...

  2. 46 CFR 167.40-45 - Magnetic compass and gyrocompass.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Magnetic compass and gyrocompass. 167.40-45 Section 167... NAUTICAL SCHOOL SHIPS Certain Equipment Requirements § 167.40-45 Magnetic compass and gyrocompass. (a) All mechanically propelled vessels in ocean or coastwise service must be fitted with a magnetic compass. (b)...

  3. 46 CFR 108.715 - Magnetic compass and gyrocompass.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Magnetic compass and gyrocompass. 108.715 Section 108... DESIGN AND EQUIPMENT Miscellaneous Equipment § 108.715 Magnetic compass and gyrocompass. (a) Each self-propelled unit in ocean or coastwise service must have a magnetic compass. (b) Each self-propelled unit of...

  4. Compass Games: An Introduction to Orienteering Skills

    ERIC Educational Resources Information Center

    Sension-Hall, Debra

    2011-01-01

    Compasses are useful tools for teaching the basics of navigation. Knowing where you are, where you are going, and how to get there are important facets of outdoor recreation. Compass games are a fun way to teach introductory navigation skills, and this article describes how they can be used as innovative, nontraditional activities in physical…

  5. 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...

  6. Tenebrio beetles use magnetic inclination compass

    NASA Astrophysics Data System (ADS)

    Vácha, Martin; Drštková, Dana; Půžová, 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.

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

    PubMed

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

    2004-05-13

    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 a vertically aligned broadband (0.1-10 MHz) or a single-frequency (7-MHz) field in addition to the geomagnetic field. Moreover, in the 7-MHz oscillating field, this effect depended on the angle between the oscillating and the geomagnetic fields. The birds exhibited seasonally appropriate migratory orientation when the oscillating field was parallel to the geomagnetic field, but were disoriented when it was presented at a 24 degrees or 48 degrees angle. These results are consistent with a resonance effect on singlet-triplet transitions and suggest a magnetic compass based on a radical-pair mechanism.

  8. Orientation at night: an innate moon compass in sandhoppers (Amphipoda: Talitridae).

    PubMed

    Ugolini, Alberto; Fantini, Tiziana; Innocenti, Riccardo

    2003-02-01

    The supralittoral amphipod Talitrus saltator is well known for its capacity for astronomical orientation using the sun and moon as compasses. It has also been demonstrated that the sun compass is innate in this species. In our experiments, we released inexpert (naive) young born in the laboratory into a confined environment under the full moon and in the absence of the horizontal component of the magnetic field. They were allowed to see the natural sky and the moon only at the moment of release. The young individuals were obtained in the laboratory by crossing adult individuals from the same and different populations of sandhoppers. The young from intrapopulation crosses were well oriented towards the directions corresponding to those of their parents, whereas the young from interpopulation crosses were oriented in an intermediate direction. Therefore, our experiments demonstrate in the sandhopper T. saltator that sea-land moon orientation relies on an innate chronometrically compensated mechanism.

  9. Migratory blackcaps can use their magnetic compass at 5 degrees inclination, but are completely random at 0 degrees inclination

    PubMed Central

    Schwarze, Susanne; Steenken, Friederike; Thiele, Nadine; Kobylkov, Dmitry; Lefeldt, Nele; Dreyer, David; Schneider, Nils-Lasse; Mouritsen, Henrik

    2016-01-01

    It is known that night-migratory songbirds use a magnetic compass measuring the magnetic inclination angle, i.e. the angle between the Earth’s surface and the magnetic field lines, but how do such birds orient at the magnetic equator? A previous study reported that birds are completely randomly oriented in a horizontal north-south magnetic field with 0° inclination angle. This seems counter-intuitive, because birds using an inclination compass should be able to separate the north-south axis from the east-west axis, so that bimodal orientation might be expected in a horizontal field. Furthermore, little is known about how shallow inclination angles migratory birds can still use for orientation. In this study, we tested the magnetic compass orientation of night-migratory Eurasian blackcaps (Sylvia atricapilla) in magnetic fields with 5° and 0° inclination. At 5° inclination, the birds oriented as well as they did in the normal 67° inclined field in Oldenburg. In contrast, they were completely randomly oriented in the horizontal field, showing no sign of bimodality. Our results indicate that the inclination limit for the magnetic compass of the blackcap is below 5° and that these birds indeed seem completely unable to use their magnetic compass for orientation in a horizontal magnetic field. PMID:27667569

  10. Avian magnetic compass can be tuned to anomalously low magnetic intensities.

    PubMed

    Winklhofer, Michael; Dylda, Evelyn; Thalau, Peter; Wiltschko, Wolfgang; Wiltschko, Roswitha

    2013-07-22

    The avian magnetic compass works in a fairly narrow functional window around the intensity of the local geomagnetic field, but adjusts to intensities outside this range when birds experience these new intensities for a certain time. In the past, the geomagnetic field has often been much weaker than at present. To find out whether birds can obtain directional information from a weak magnetic field, we studied spontaneous orientation preferences of migratory robins in a 4 µT field (i.e. a field of less than 10 per cent of the local intensity of 47 µT). Birds can adjust to this low intensity: they turned out to be disoriented under 4 µT after a pre-exposure time of 8 h to 4 µT, but were able to orient in this field after a total exposure time of 17 h. This demonstrates a considerable plasticity of the avian magnetic compass. Orientation in the 4 µT field was not affected by local anaesthesia of the upper beak, but was disrupted by a radiofrequency magnetic field of 1.315 MHz, 480 nT, suggesting that a radical-pair mechanism still provides the directional information in the low magnetic field. This is in agreement with the idea that the avian magnetic compass may have developed already in the Mesozoic in the common ancestor of modern birds.

  11. Avian magnetic compass can be tuned to anomalously low magnetic intensities.

    PubMed

    Winklhofer, Michael; Dylda, Evelyn; Thalau, Peter; Wiltschko, Wolfgang; Wiltschko, Roswitha

    2013-07-22

    The avian magnetic compass works in a fairly narrow functional window around the intensity of the local geomagnetic field, but adjusts to intensities outside this range when birds experience these new intensities for a certain time. In the past, the geomagnetic field has often been much weaker than at present. To find out whether birds can obtain directional information from a weak magnetic field, we studied spontaneous orientation preferences of migratory robins in a 4 µT field (i.e. a field of less than 10 per cent of the local intensity of 47 µT). Birds can adjust to this low intensity: they turned out to be disoriented under 4 µT after a pre-exposure time of 8 h to 4 µT, but were able to orient in this field after a total exposure time of 17 h. This demonstrates a considerable plasticity of the avian magnetic compass. Orientation in the 4 µT field was not affected by local anaesthesia of the upper beak, but was disrupted by a radiofrequency magnetic field of 1.315 MHz, 480 nT, suggesting that a radical-pair mechanism still provides the directional information in the low magnetic field. This is in agreement with the idea that the avian magnetic compass may have developed already in the Mesozoic in the common ancestor of modern birds. PMID:23720547

  12. Avian magnetic compass can be tuned to anomalously low magnetic intensities

    PubMed Central

    Winklhofer, Michael; Dylda, Evelyn; Thalau, Peter; Wiltschko, Wolfgang; Wiltschko, Roswitha

    2013-01-01

    The avian magnetic compass works in a fairly narrow functional window around the intensity of the local geomagnetic field, but adjusts to intensities outside this range when birds experience these new intensities for a certain time. In the past, the geomagnetic field has often been much weaker than at present. To find out whether birds can obtain directional information from a weak magnetic field, we studied spontaneous orientation preferences of migratory robins in a 4 µT field (i.e. a field of less than 10 per cent of the local intensity of 47 µT). Birds can adjust to this low intensity: they turned out to be disoriented under 4 µT after a pre-exposure time of 8 h to 4 µT, but were able to orient in this field after a total exposure time of 17 h. This demonstrates a considerable plasticity of the avian magnetic compass. Orientation in the 4 µT field was not affected by local anaesthesia of the upper beak, but was disrupted by a radiofrequency magnetic field of 1.315 MHz, 480 nT, suggesting that a radical-pair mechanism still provides the directional information in the low magnetic field. This is in agreement with the idea that the avian magnetic compass may have developed already in the Mesozoic in the common ancestor of modern birds. PMID:23720547

  13. 46 CFR 108.715 - Magnetic compass and gyrocompass.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Magnetic compass and gyrocompass. 108.715 Section 108.715 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Miscellaneous Equipment § 108.715 Magnetic compass and gyrocompass. (a) Each self-propelled unit in ocean or coastwise...

  14. 46 CFR 108.715 - Magnetic compass and gyrocompass.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Magnetic compass and gyrocompass. 108.715 Section 108.715 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Miscellaneous Equipment § 108.715 Magnetic compass and gyrocompass. (a) Each self-propelled unit in ocean or coastwise...

  15. Re-calibration of the magnetic compass in hand-raised European robins (Erithacus rubecula).

    PubMed

    Alert, Bianca; Michalik, Andreas; Thiele, Nadine; Bottesch, Michael; Mouritsen, Henrik

    2015-09-21

    Migratory birds can use a variety of environmental cues for orientation. A primary calibration between the celestial and magnetic compasses seems to be fundamental prior to a bird's first autumn migration. Releasing hand-raised or rescued young birds back into the wild might therefore be a problem because they might not have established a functional orientation system during their first calendar year. Here, we test whether hand-raised European robins that did not develop any functional compass before or during their first autumn migration could relearn to orient if they were exposed to natural celestial cues during the subsequent winter and spring. When tested in the geomagnetic field without access to celestial cues, these birds could orient in their species-specific spring migratory direction. In contrast, control birds that were deprived of any natural celestial cues throughout remained unable to orient. Our experiments suggest that European robins are still capable of establishing a functional orientation system after their first autumn. Although the external reference remains speculative, most likely, natural celestial cues enabled our birds to calibrate their magnetic compass. Our data suggest that avian compass systems are more flexible than previously believed and have implications for the release of hand-reared migratory birds.

  16. Re-calibration of the magnetic compass in hand-raised European robins (Erithacus rubecula).

    PubMed

    Alert, Bianca; Michalik, Andreas; Thiele, Nadine; Bottesch, Michael; Mouritsen, Henrik

    2015-01-01

    Migratory birds can use a variety of environmental cues for orientation. A primary calibration between the celestial and magnetic compasses seems to be fundamental prior to a bird's first autumn migration. Releasing hand-raised or rescued young birds back into the wild might therefore be a problem because they might not have established a functional orientation system during their first calendar year. Here, we test whether hand-raised European robins that did not develop any functional compass before or during their first autumn migration could relearn to orient if they were exposed to natural celestial cues during the subsequent winter and spring. When tested in the geomagnetic field without access to celestial cues, these birds could orient in their species-specific spring migratory direction. In contrast, control birds that were deprived of any natural celestial cues throughout remained unable to orient. Our experiments suggest that European robins are still capable of establishing a functional orientation system after their first autumn. Although the external reference remains speculative, most likely, natural celestial cues enabled our birds to calibrate their magnetic compass. Our data suggest that avian compass systems are more flexible than previously believed and have implications for the release of hand-reared migratory birds. PMID:26388258

  17. 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

  18. Not all songbirds calibrate their magnetic compass from twilight cues: a telemetry study.

    PubMed

    Chernetsov, Nikita; Kishkinev, Dmitry; Kosarev, Vladislav; Bolshakov, Casimir V

    2011-08-01

    Migratory birds are able to use the sun and associated polarised light patterns, stellar cues and the geomagnetic field for orientation. No general agreement has been reached regarding the hierarchy of orientation cues. Recent data from naturally migrating North American Catharus thrushes suggests that they calibrate geomagnetic information daily from twilight cues. Similar results have been shown in caged birds in a few studies but not confirmed in others. We report that free-flying European migrants, song thrushes Turdus philomelos, released after pre-exposure to a horizontally rotated magnetic field, do not recalibrate their magnetic compass from solar cues, but rather show a simple domination of either the magnetic or the stellar compass. We suggest that different songbird species possess different hierarchies of orientation cues, depending on the geographic and ecological challenges met by the migrants. PMID:21753048

  19. Night-Migratory Songbirds Possess a Magnetic Compass in Both Eyes

    PubMed Central

    Lefeldt, Nele; Prior, Helmut; Mouritsen, Henrik

    2012-01-01

    Previous studies on European robins, Erithacus rubecula, and Australian silvereyes, Zosterops lateralis, had suggested that magnetic compass information is being processed only in the right eye and left brain hemisphere of migratory birds. However, recently it was demonstrated that both garden warblers, Sylvia borin, and European robins have a magnetic compass in both eyes. These results raise the question if the strong lateralization effect observed in earlier experiments might have arisen from artifacts or from differences in experimental conditions rather than reflecting a true all-or-none lateralization of the magnetic compass in European robins. Here we show that (1) European robins having only their left eye open can orient in their seasonally appropriate direction both during autumn and spring, i.e. there are no strong lateralization differences between the outward journey and the way home, that (2) their directional choices are based on the standard inclination compass as they are turned 180° when the inclination is reversed, and that (3) the capability to use the magnetic compass does not depend on monocular learning or intraocular transfer as it is already present in the first tests of the birds with only one eye open. PMID:22984416

  20. 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

  1. 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.

  2. Sun-Compass Orientation in Mediterranean Fish Larvae

    PubMed Central

    Faillettaz, Robin; Blandin, Agathe; Paris, Claire B.; Koubbi, Philippe; Irisson, Jean-Olivier

    2015-01-01

    Mortality is very high during the pelagic larval phase of fishes but the factors that determine recruitment success remain unclear and hard to predict. Because of their bipartite life history, larvae of coastal species have to head back to the shore at the end of their pelagic episode, to settle. These settlement-stage larvae are known to display strong sensory and motile abilities, but most work has been focused on tropical, insular environments and on the influence of coast-related cues on orientation. In this study we quantified the in situ orientation behavior of settlement-stage larvae in a temperate region, with a continuous coast and a dominant along-shore current, and inspected both coast-dependent and independent cues. We tested six species: one Pomacentridae, Chromis chromis, and five Sparidae, Boops boops, Diplodus annularis, Oblada melanura, Spicara smaris and Spondyliosoma cantharus. Over 85% of larvae were highly capable of keeping a bearing, which is comparable to the orientation abilities of tropical species. Sun-related cues influenced the precision of bearing-keeping at individual level. Three species, out of the four tested in sufficient numbers, oriented significantly relative to the sun position. These are the first in situ observations demonstrating the use of a sun compass for orientation by wild-caught settlement-stage larvae. This mechanism has potential for large-scale orientation of fish larvae globally. PMID:26308915

  3. Sun-Compass Orientation in Mediterranean Fish Larvae.

    PubMed

    Faillettaz, Robin; Blandin, Agathe; Paris, Claire B; Koubbi, Philippe; Irisson, Jean-Olivier

    2015-01-01

    Mortality is very high during the pelagic larval phase of fishes but the factors that determine recruitment success remain unclear and hard to predict. Because of their bipartite life history, larvae of coastal species have to head back to the shore at the end of their pelagic episode, to settle. These settlement-stage larvae are known to display strong sensory and motile abilities, but most work has been focused on tropical, insular environments and on the influence of coast-related cues on orientation. In this study we quantified the in situ orientation behavior of settlement-stage larvae in a temperate region, with a continuous coast and a dominant along-shore current, and inspected both coast-dependent and independent cues. We tested six species: one Pomacentridae, Chromis chromis, and five Sparidae, Boops boops, Diplodus annularis, Oblada melanura, Spicara smaris and Spondyliosoma cantharus. Over 85% of larvae were highly capable of keeping a bearing, which is comparable to the orientation abilities of tropical species. Sun-related cues influenced the precision of bearing-keeping at individual level. Three species, out of the four tested in sufficient numbers, oriented significantly relative to the sun position. These are the first in situ observations demonstrating the use of a sun compass for orientation by wild-caught settlement-stage larvae. This mechanism has potential for large-scale orientation of fish larvae globally. PMID:26308915

  4. 46 CFR 32.15-35 - Magnetic Compass and Gyrocompass-T/OC.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Magnetic Compass and Gyrocompass-T/OC. 32.15-35 Section..., MACHINERY, AND HULL REQUIREMENTS Navigation Equipment § 32.15-35 Magnetic Compass and Gyrocompass—T/OC. (a) All tankships in ocean or coastwise service must be fitted with a magnetic compass. (b) All...

  5. 46 CFR 32.15-35 - Magnetic Compass and Gyrocompass-T/OC.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Magnetic Compass and Gyrocompass-T/OC. 32.15-35 Section..., MACHINERY, AND HULL REQUIREMENTS Navigation Equipment § 32.15-35 Magnetic Compass and Gyrocompass—T/OC. (a) All tankships in ocean or coastwise service must be fitted with a magnetic compass. (b) All...

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

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Magnetic Compass and Gyrocompass-T/OC. 32.15-35 Section..., MACHINERY, AND HULL REQUIREMENTS Navigation Equipment § 32.15-35 Magnetic Compass and Gyrocompass—T/OC. (a) All tankships in ocean or coastwise service must be fitted with a magnetic compass. (b) All...

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

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Magnetic Compass and Gyrocompass-T/OC. 32.15-35 Section..., MACHINERY, AND HULL REQUIREMENTS Navigation Equipment § 32.15-35 Magnetic Compass and Gyrocompass—T/OC. (a) All tankships in ocean or coastwise service must be fitted with a magnetic compass. (b) All...

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

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Magnetic Compass and Gyrocompass-T/OC. 32.15-35 Section..., MACHINERY, AND HULL REQUIREMENTS Navigation Equipment § 32.15-35 Magnetic Compass and Gyrocompass—T/OC. (a) All tankships in ocean or coastwise service must be fitted with a magnetic compass. (b) All...

  9. The magnetic compass mechanisms of birds and rodents are based on different physical principles.

    PubMed

    Thalau, Peter; Ritz, Thorsten; Burda, Hynek; Wegner, Regina E; Wiltschko, Roswitha

    2006-08-22

    Recently, oscillating magnetic fields in the MHz-range were introduced as a useful diagnostic tool to identify the mechanism underlying magnetoreception. The effect of very weak high-frequency fields on the orientation of migratory birds indicates that the avian magnetic compass is based on a radical pair mechanism. To analyse the nature of the magnetic compass of mammals, we tested rodents, Ansell's mole-rats, using their tendency to build their nests in the southern part of the arena as a criterion whether or not they could orient. In contrast to birds, their orientation was not disrupted when a broad-band field of 0.1-10MHz of 85nT or a 1.315MHz field of 480nT was added to the static geomagnetic field of 46000nT. Even increasing the intensity of the 1.315MHz field (Zeeman frequency in the local geomagnetic field) to 4800nT, more than a tenth of the static field, the mole-rats remained unaffected and continued to build their nests in the south. These results indicate that in contrast to that of birds, their magnetic compass does not involve radical pair processes; it seems to be based on a fundamentally different principle, which probably involves magnetite.

  10. Exotic skyrmion crystals in chiral magnets with compass anisotropy.

    PubMed

    Chen, J P; Zhang, Dan-Wei; Liu, J-M

    2016-01-01

    The compass-type anisotropy appears naturally in diverse physical contexts with strong spin-orbit coupling (SOC) such as transition metal oxides and cold atomic gases etc, and it has been receiving substantial attention. Motivated by recent studies and particularly recent experimental observations on helimagnet MnGe, we investigate the critical roles of this compass-type anisotropy in modulating various spin textures of chiral magnets with strong SOC, by Monte Carlo simulations based on a classical Heisenberg spin model with Dzyaloshinsky-Moriya interaction and compass anisotropy. A phase diagram with emergent spin orders in the space of compass anisotropy and out-of-plane magnetic field is presented. In this phase diagram, we propose that a hybrid super-crystal structure consisting of alternating half-skyrmion and half-anti-skyrmion is the possible zero-field ground state of MnGe. The simulated evolution of the spin structure driven by magnetic field is in good accordance with experimental observations on MnGe. Therefore, this Heisenberg spin model successfully captures the main physics responsible for the magnetic structures in MnGe, and the present work may also be instructive to research on the magnetic states in other systems with strong SOC. PMID:27377149

  11. Exotic skyrmion crystals in chiral magnets with compass anisotropy

    PubMed Central

    Chen, J. P.; Zhang, Dan-Wei; Liu, J. -M.

    2016-01-01

    The compass-type anisotropy appears naturally in diverse physical contexts with strong spin-orbit coupling (SOC) such as transition metal oxides and cold atomic gases etc, and it has been receiving substantial attention. Motivated by recent studies and particularly recent experimental observations on helimagnet MnGe, we investigate the critical roles of this compass-type anisotropy in modulating various spin textures of chiral magnets with strong SOC, by Monte Carlo simulations based on a classical Heisenberg spin model with Dzyaloshinsky-Moriya interaction and compass anisotropy. A phase diagram with emergent spin orders in the space of compass anisotropy and out-of-plane magnetic field is presented. In this phase diagram, we propose that a hybrid super-crystal structure consisting of alternating half-skyrmion and half-anti-skyrmion is the possible zero-field ground state of MnGe. The simulated evolution of the spin structure driven by magnetic field is in good accordance with experimental observations on MnGe. Therefore, this Heisenberg spin model successfully captures the main physics responsible for the magnetic structures in MnGe, and the present work may also be instructive to research on the magnetic states in other systems with strong SOC. PMID:27377149

  12. Exotic skyrmion crystals in chiral magnets with compass anisotropy

    NASA Astrophysics Data System (ADS)

    Chen, J. P.; Zhang, Dan-Wei; Liu, J.-M.

    2016-07-01

    The compass-type anisotropy appears naturally in diverse physical contexts with strong spin-orbit coupling (SOC) such as transition metal oxides and cold atomic gases etc, and it has been receiving substantial attention. Motivated by recent studies and particularly recent experimental observations on helimagnet MnGe, we investigate the critical roles of this compass-type anisotropy in modulating various spin textures of chiral magnets with strong SOC, by Monte Carlo simulations based on a classical Heisenberg spin model with Dzyaloshinsky-Moriya interaction and compass anisotropy. A phase diagram with emergent spin orders in the space of compass anisotropy and out-of-plane magnetic field is presented. In this phase diagram, we propose that a hybrid super-crystal structure consisting of alternating half-skyrmion and half-anti-skyrmion is the possible zero-field ground state of MnGe. The simulated evolution of the spin structure driven by magnetic field is in good accordance with experimental observations on MnGe. Therefore, this Heisenberg spin model successfully captures the main physics responsible for the magnetic structures in MnGe, and the present work may also be instructive to research on the magnetic states in other systems with strong SOC.

  13. A nocturnal mammal, the greater mouse-eared bat, calibrates a magnetic compass by the sun

    PubMed Central

    Holland, Richard A.; Borissov, Ivailo; Siemers, Björn M.

    2010-01-01

    Recent evidence suggests that bats can detect the geomagnetic field, but the way in which this is used by them for navigation to a home roost remains unresolved. The geomagnetic field may be used by animals both to indicate direction and to locate position. In birds, directional information appears to be derived from an interaction of the magnetic field with either the sun or the stars, with some evidence suggesting that sunset/sunrise provides the primary directional reference by which a magnetic compass is calibrated daily. We demonstrate that homing greater mouse-eared bats (Myotis myotis) calibrate a magnetic compass with sunset cues by testing their homing response after exposure to an altered magnetic field at and after sunset. Magnetic manipulation at sunset resulted in a counterclockwise shift in orientation compared with controls, consistent with sunset calibration of the magnetic field, whereas magnetic manipulation after sunset resulted in no change in orientation. Unlike in birds, however, the pattern of polarization was not necessary for the calibration. For animals that occupy ecological niches where the sunset is rarely observed, this is a surprising finding. Yet it may indicate the primacy of the sun as an absolute geographical reference not only for birds but also within other vertebrate taxa. PMID:20351296

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

    NASA Astrophysics Data System (ADS)

    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.

  15. The quantum needle of the avian magnetic compass.

    PubMed

    Hiscock, Hamish G; Worster, Susannah; Kattnig, Daniel R; Steers, Charlotte; Jin, Ye; Manolopoulos, David E; Mouritsen, Henrik; Hore, P J

    2016-04-26

    Migratory birds have a light-dependent magnetic compass, the mechanism of which is thought to involve radical pairs formed photochemically in cryptochrome proteins in the retina. Theoretical descriptions of this compass have thus far been unable to account for the high precision with which birds are able to detect the direction of the Earth's magnetic field. Here we use coherent spin dynamics simulations to explore the behavior of realistic models of cryptochrome-based radical pairs. We show that when the spin coherence persists for longer than a few microseconds, the output of the sensor contains a sharp feature, referred to as a spike. The spike arises from avoided crossings of the quantum mechanical spin energy-levels of radicals formed in cryptochromes. Such a feature could deliver a heading precision sufficient to explain the navigational behavior of migratory birds in the wild. Our results (i) afford new insights into radical pair magnetoreception, (ii) suggest ways in which the performance of the compass could have been optimized by evolution, (iii) may provide the beginnings of an explanation for the magnetic disorientation of migratory birds exposed to anthropogenic electromagnetic noise, and (iv) suggest that radical pair magnetoreception may be more of a quantum biology phenomenon than previously realized. PMID:27044102

  16. 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…

  17. Electronic solar compass for high precision orientation on any planet

    NASA Astrophysics Data System (ADS)

    Flora, F.; Bollanti, S.; De Meis, D.; Di Lazzaro, P.; Gallerano, G. P.; Mezi, L.; Murra, D.; Torre, A.; Vicca, D.

    2016-07-01

    A compact, fully automatic electronic solar compass has been developed at the ENEA Frascati Laboratories. The compass is inspired to ``camera obscura'' sundials like those inside churches. Sun ephemerides are calculated using an approximate but effective analytical solution of Kepler's laws, where the Earth (or other planets) orbit main parameters are introduced. The instrument is light, cheap and it has an accuracy better than 1 arcmin. Some examples of application of the device as well as the possibility to use it on Mars are presented.

  18. 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

  19. 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.

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

    SciTech Connect

    Cahyna, P.; Fuchs, V.; Krlin, L.

    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.

  1. Sky Compass Orientation in Desert Locusts—Evidence from Field and Laboratory Studies

    PubMed Central

    Homberg, Uwe

    2015-01-01

    Locusts are long-range migratory insects. At high population density, immature animals form marching hopper bands while adults take off and form huge swarms of millions of animals. At low population densities animals are solitarious, but likewise migrate, mostly during the night. Numerous studies aimed at predicting locust infestations showed that migrations both as hopper bands and as adults are largely downwind following seasonal shifts of the tropical convergence zone taking the animals to areas of rainfall. Only a few studies provided evidence for active orientation mechanisms, including the involvement of a sun compass. This scarcity of evidence stands in contrast to recent neurobiological data showing sophisticated neuronal adaptations suited for sky compass navigation. These include a special dorsal eye region with photoreceptors suited to analyze the polarization pattern of the sky and a system of topographically arranged sky compass neurons in the central complex of the brain. Laboratory experiments, moreover, demonstrated polarotaxis in tethered flying animals. The discrepancy of these findings call for more rigorous field studies on active orientation mechanisms in locusts. It remains to be shown how locusts use their internal sky compass during mass migrations and what role it plays to guide solitarious locusts in their natural habitat. PMID:26733834

  2. Sky Compass Orientation in Desert Locusts-Evidence from Field and Laboratory Studies.

    PubMed

    Homberg, Uwe

    2015-01-01

    Locusts are long-range migratory insects. At high population density, immature animals form marching hopper bands while adults take off and form huge swarms of millions of animals. At low population densities animals are solitarious, but likewise migrate, mostly during the night. Numerous studies aimed at predicting locust infestations showed that migrations both as hopper bands and as adults are largely downwind following seasonal shifts of the tropical convergence zone taking the animals to areas of rainfall. Only a few studies provided evidence for active orientation mechanisms, including the involvement of a sun compass. This scarcity of evidence stands in contrast to recent neurobiological data showing sophisticated neuronal adaptations suited for sky compass navigation. These include a special dorsal eye region with photoreceptors suited to analyze the polarization pattern of the sky and a system of topographically arranged sky compass neurons in the central complex of the brain. Laboratory experiments, moreover, demonstrated polarotaxis in tethered flying animals. The discrepancy of these findings call for more rigorous field studies on active orientation mechanisms in locusts. It remains to be shown how locusts use their internal sky compass during mass migrations and what role it plays to guide solitarious locusts in their natural habitat. PMID:26733834

  3. Driven magnetic reconnection in the COMPASS-C tokamak

    SciTech Connect

    Morris, A.W.; Carolan, P.G.; Fitzpatrick, R.; Hender, T.C.; Todd, T.N. , Abingdon, Oxon )

    1992-02-01

    The question of the influence of nonaxisymmetric field perturbations on tokamaks is investigated. Recent experiments in the COMPASS-C tokamak (in {ital Proceedings} {ital of} {ital the} 15{ital th} {ital Symposium} {ital on} {ital Fusion} {ital Technology}, Utrecht (North-Holland, Amsterdam, 1989), Vol. 1, p. 361) with externally applied helical fields reveal that magnetic islands do not appear until the applied field exceeds a certain value, when plasma rotation and confinement are affected. A new resistive magnetohydrodynamic model including plasma rotation now provides an explanation of this threshold, and is quantitatively consistent with experimental results in Ohmic plasmas. The results indicate the tolerable error fields in future tokamaks. The effects of perturbations with various poloidal and toroidal mode numbers have been studied.

  4. Rapid learning of magnetic compass direction by C57BL/6 mice in a 4-armed 'plus' water maze.

    PubMed

    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.

  5. Rapid learning of magnetic compass direction by C57BL/6 mice in a 4-armed 'plus' water maze.

    PubMed

    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

  6. 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.

  7. X-ray compass for determining device orientation

    DOEpatents

    Da Silva, Luiz B.; Matthews, Dennis L.; Fitch, Joseph P.; Everett, Matthew J.; Colston, Billy W.; Stone, Gary F.

    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.

  8. Freely oriented portable superconducting magnet

    SciTech Connect

    Schmierer, Eric N.; Prenger, F. Coyne; Hill, Dallas D.

    2010-01-12

    A freely oriented portable superconducting magnet is disclosed. Coolant is supplied to the superconducting magnet from a repository separate from the magnet, enabling portability of the magnet. A plurality of support assemblies structurally anchor and thermally isolate the magnet within a thermal shield. A plurality of support assemblies structurally anchor and thermally isolate the thermal shield within a vacuum vessel. The support assemblies restrain movement of the magnet resulting from energizing and cooldown, as well as from changes in orientation, enabling the magnet to be freely orientable.

  9. Magnetic orientation of garden warblers (Sylvia borin) under 1.4 MHz radiofrequency magnetic field.

    PubMed

    Kavokin, Kirill; Chernetsov, Nikita; Pakhomov, Alexander; Bojarinova, Julia; Kobylkov, Dmitry; Namozov, Barot

    2014-08-01

    We report on the experiments on orientation of a migratory songbird, the garden warbler (Sylvia borin), during the autumn migration period on the Courish Spit, Eastern Baltics. Birds in experimental cages, deprived of visual information, showed the seasonally appropriate direction of intended flight with respect to the magnetic meridian. Weak radiofrequency (RF) magnetic field (190 nT at 1.4 MHz) disrupted this orientation ability. These results may be considered as an independent replication of earlier experiments, performed by the group of R. and W. Wiltschko with European robins (Erithacus rubecula). Confirmed outstanding sensitivity of the birds' magnetic compass to RF fields in the lower megahertz range demands for a revision of one of the mainstream theories of magnetoreception, the radical-pair model of birds' magnetic compass.

  10. Magnetic orientation of garden warblers (Sylvia borin) under 1.4 MHz radiofrequency magnetic field.

    PubMed

    Kavokin, Kirill; Chernetsov, Nikita; Pakhomov, Alexander; Bojarinova, Julia; Kobylkov, Dmitry; Namozov, Barot

    2014-08-01

    We report on the experiments on orientation of a migratory songbird, the garden warbler (Sylvia borin), during the autumn migration period on the Courish Spit, Eastern Baltics. Birds in experimental cages, deprived of visual information, showed the seasonally appropriate direction of intended flight with respect to the magnetic meridian. Weak radiofrequency (RF) magnetic field (190 nT at 1.4 MHz) disrupted this orientation ability. These results may be considered as an independent replication of earlier experiments, performed by the group of R. and W. Wiltschko with European robins (Erithacus rubecula). Confirmed outstanding sensitivity of the birds' magnetic compass to RF fields in the lower megahertz range demands for a revision of one of the mainstream theories of magnetoreception, the radical-pair model of birds' magnetic compass. PMID:24942848

  11. Magnetic orientation of garden warblers (Sylvia borin) under 1.4 MHz radiofrequency magnetic field

    PubMed Central

    Kavokin, Kirill; Chernetsov, Nikita; Pakhomov, Alexander; Bojarinova, Julia; Kobylkov, Dmitry; Namozov, Barot

    2014-01-01

    We report on the experiments on orientation of a migratory songbird, the garden warbler (Sylvia borin), during the autumn migration period on the Courish Spit, Eastern Baltics. Birds in experimental cages, deprived of visual information, showed the seasonally appropriate direction of intended flight with respect to the magnetic meridian. Weak radiofrequency (RF) magnetic field (190 nT at 1.4 MHz) disrupted this orientation ability. These results may be considered as an independent replication of earlier experiments, performed by the group of R. and W. Wiltschko with European robins (Erithacus rubecula). Confirmed outstanding sensitivity of the birds' magnetic compass to RF fields in the lower megahertz range demands for a revision of one of the mainstream theories of magnetoreception, the radical-pair model of birds' magnetic compass. PMID:24942848

  12. 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

  13. Orientation with a Viking sun-compass, a shadow-stick, and two calcite sunstones under various weather conditions.

    PubMed

    Bernáth, Balázs; Blahó, Miklós; Egri, Adám; Barta, András; Kriska, György; Horváth, Gábor

    2013-09-01

    It is widely accepted that Vikings used sun-compasses to derive true directions from the cast shadow of a gnomon. It has been hypothesized that when a cast shadow was not formed, Viking navigators relied on crude skylight polarimetry with the aid of dichroic or birefringent crystals, called "sunstones." We demonstrate here that a simple tool, that we call "shadow-stick," could have allowed orientation by a sun-compass with satisfying accuracy when shadows were not formed, but the sun position could have reliably been estimated. In field tests, we performed orientation trials with a set composed of a sun-compass, two calcite sunstones, and a shadow-stick. We show here that such a set could have been an effective orientation tool for Vikings only when clear, blue patches of the sky were visible. PMID:24085076

  14. Orientation with a Viking sun-compass, a shadow-stick, and two calcite sunstones under various weather conditions.

    PubMed

    Bernáth, Balázs; Blahó, Miklós; Egri, Adám; Barta, András; Kriska, György; Horváth, Gábor

    2013-09-01

    It is widely accepted that Vikings used sun-compasses to derive true directions from the cast shadow of a gnomon. It has been hypothesized that when a cast shadow was not formed, Viking navigators relied on crude skylight polarimetry with the aid of dichroic or birefringent crystals, called "sunstones." We demonstrate here that a simple tool, that we call "shadow-stick," could have allowed orientation by a sun-compass with satisfying accuracy when shadows were not formed, but the sun position could have reliably been estimated. In field tests, we performed orientation trials with a set composed of a sun-compass, two calcite sunstones, and a shadow-stick. We show here that such a set could have been an effective orientation tool for Vikings only when clear, blue patches of the sky were visible.

  15. 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.

  16. 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.

  17. Should animals navigating over short distances switch to a magnetic compass sense?

    PubMed

    Wyeth, Russell C

    2010-01-01

    Magnetoreception can play a substantial role in long distance navigation by animals. I hypothesize that locomotion guided by a magnetic compass sense could also play a role in short distance navigation. Animals identify mates, prey, or other short distance navigational goals using different sensory modalities (olfaction, vision, audition, etc.) to detect sensory cues associated with those goals. In conditions where these cues become unreliable for navigation (due to flow changes, obstructions, noise interference, etc.), switching to a magnetic compass sense to guide locomotion toward the navigational goals could be beneficial. Using simulations based on known locomotory and flow parameters, I show this strategy has strong theoretical benefits for the nudibranch mollusk Tritonia diomedea navigating toward odor sources in variable flow. A number of other animals may garner similar benefits, particularly slow-moving species in environments with rapidly changing cues relevant for navigation. Faster animals might also benefit from switching to a magnetic compass sense, provided the initial cues used for navigation (acoustic signals, odors, etc.) are intermittent or change rapidly enough that the entire navigation behavior cannot be guided by a continuously detectable cue. Examination of the relative durations of navigational tasks, the persistence of navigational cues, and the stability of both navigators and navigational targets will identify candidates with the appropriate combination of unreliable initial cues and relatively immobile navigational goals for which this hypothetical behavior could be beneficial. Magnetic manipulations can then test whether a switch to a magnetic compass sense occurs. This hypothesis thus provides an alternative when considering the behavioral significance of a magnetic compass sense in animals. PMID:20740070

  18. Should Animals Navigating Over Short Distances Switch to a Magnetic Compass Sense?

    PubMed Central

    Wyeth, Russell C.

    2010-01-01

    Magnetoreception can play a substantial role in long distance navigation by animals. I hypothesize that locomotion guided by a magnetic compass sense could also play a role in short distance navigation. Animals identify mates, prey, or other short distance navigational goals using different sensory modalities (olfaction, vision, audition, etc.) to detect sensory cues associated with those goals. In conditions where these cues become unreliable for navigation (due to flow changes, obstructions, noise interference, etc.), switching to a magnetic compass sense to guide locomotion toward the navigational goals could be beneficial. Using simulations based on known locomotory and flow parameters, I show this strategy has strong theoretical benefits for the nudibranch mollusk Tritonia diomedea navigating toward odor sources in variable flow. A number of other animals may garner similar benefits, particularly slow-moving species in environments with rapidly changing cues relevant for navigation. Faster animals might also benefit from switching to a magnetic compass sense, provided the initial cues used for navigation (acoustic signals, odors, etc.) are intermittent or change rapidly enough that the entire navigation behavior cannot be guided by a continuously detectable cue. Examination of the relative durations of navigational tasks, the persistence of navigational cues, and the stability of both navigators and navigational targets will identify candidates with the appropriate combination of unreliable initial cues and relatively immobile navigational goals for which this hypothetical behavior could be beneficial. Magnetic manipulations can then test whether a switch to a magnetic compass sense occurs. This hypothesis thus provides an alternative when considering the behavioral significance of a magnetic compass sense in animals. PMID:20740070

  19. 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

  20. 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.

  1. Magnetic order and spin excitations in layered Heisenberg antiferromagnets with compass-model anisotropies

    NASA Astrophysics Data System (ADS)

    Vladimirov, A. A.; Ihle, D.; Plakida, N. M.

    2015-02-01

    The spin-wave excitation spectrum, magnetization, and Néel temperature for the quasi-two-dimensional spin-1/2 antiferromagnetic Heisenberg model with the compass-model interaction in the plane proposed for iridates are calculated in the random phase approximation. The spin-wave spectrum agrees well with data of Lanczos diagonalization. We find that the Néel temperature is enhanced by the compass-model interaction and is close to the experimental value for Ba2IrO4.

  2. Orientation and Magnitude of Mars' Magnetic Field

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This image shows the orientation and magnitude of the magnetic field measured by the MGS magnetometer as it sped over the surface of Mars during an early aerobraking pass (Day of the year, 264; 'P6' periapsis pass). At each point along the spacecraft trajectory we've drawn vectors in the direction of the magnetic field measured at that instant; the length of the line is scaled to show the relative magnitude of the field. Imagine traveling along with the MGS spacecraft, holding a string with a magnetized needle on one end: this essentially a compass with a needle that is free to spin in all directions. As you pass over the surface the needle would swing rapidly, first pointing towards the planet and then rotating quickly towards 'up' and back down again. All in a relatively short span of time, say a minute or two, during which time the spacecraft has traveled a couple of hundred miles. You've just passed over one of many 'magnetic anomalies' thus far detected near the surface of Mars. A second major anomaly appears a little later along the spacecraft track, about 1/4 the magnitude of the first - can you find it? The short scale length of the magnetic field signature locates the source near the surface of Mars, perhaps in the crust, a 10 to 75 kilometer thick outer shell of the planet (radius 3397 km).

    The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO. JPL is an operating division of California Institute of Technology (Caltech).

  3. Teaching Basic Geographical Skills: Map and Compass Activities.

    ERIC Educational Resources Information Center

    Trussell, Margaret Edith

    1986-01-01

    Presents a unit on map and compass activities which introduces compass direction, magnetic declination and conversion of map measurement to familiar units. Requires four, one-hour class meetings and may be followed by a half-day orienteering activity. (Author/JDH)

  4. 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

  5. Freely Oriented, Portable Superconducting Magnet

    NASA Astrophysics Data System (ADS)

    Schmierer, E. N.; Charles, B.; Efferson, R.; Hill, D.; Jankowski, T.; Laughon, G.; Prenger, C.

    2008-03-01

    A high-field low-temperature superconducting solenoidal magnet was developed that is portable and can be operated in any orientation relative to gravity. The design consists of several features that make this feasible; 1) bulk liquid cryogen storage occurs in a separate Dewar rather than as part of the magnet assembly, which allows single-person transport due to each component of the system having low relative weight, 2) vapor generated pressurization that circulates cryogenic fluid to and from the magnet with flexible transfer lines allowing operation in any orientation, and 3) composite, low-conducting structural members are used to suspend the magnet and shield layers within the vacuum vessel that provide a robust low heat loss design. Cooling is provided to the magnet through fluid channels that are in thermal contact with the magnet. The overall design of this magnet system, some of the analyses performed that address unique behavior of this system (pressure rise during a magnet quench and transient cooldown), and test results are presented.

  6. Spin-orbit coupling, compass anisotropy and skyrmions in 2D chiral magnets

    NASA Astrophysics Data System (ADS)

    Banerjee, Sumilan; Erten, Onur; Rowland, James; Randeria, Mohit

    2014-03-01

    Spin-orbit coupling (SOC) gives rise to the chiral Dzyaloshinskii-Moriya (DM) interaction in systems that lack inversion symmetry like non-centrosymmetric helimagnets, and two-dimensional magnetism at surfaces and interfaces. We explore here the role of SOC in several microscopic exchange mechanisms - superexchange, double exchange and RKKY - in insulating and itinerant electron systems. We show that, in addition to giving rise to the DM interaction, SOC generically leads to compass anisotropy terms. Although seemingly negligible, the compass terms are energetically comparable to DM and play a crucial role in deciding the fate of the magnetic ground state. We demonstrate that the compass terms act as an effective easy-plane anisotropy in 2D chiral magnets and lead to extremely large region of stable skyrmion crystal (SkX) phase in a perpendicular magnetic field. We discuss the electronic properties of SkX in this hitherto unexplored region of the anisotropy-field plane for itinerant systems. We also comment on the possibility of realizing such SkX phase in the oxide interfaces. JR and MR supported by NSF MRSEC DMR-0820414 and SB by DOE-BES DE-SC0005035.

  7. Simultaneous poloidal measurements using new magnetically driven reciprocating probes in COMPASS

    NASA Astrophysics Data System (ADS)

    Dejarnac, R.; Gunn, J. P.; Dimitrova, M.; Hron, M.; Panek, R.; Pascal, J.-Y.; Saragosti-Chausy, C.; Tamain, P.; the COMPASS team

    2016-03-01

    Particles and heat transport in the scrape-off layer (SOL) of tokamaks is not yet fully understood. COMPASS is a small-size tokamakp where the edge plasma is well diagnosed in view of studying the competition between the parallel and the cross-field transport in the SOL. In order to better characterize SOL dynamics, in particular the poloidal asymmetry of the main parameters' radial profiles, two new in-situ magnetically driven reciprocating manipulators have been recently installed in COMPASS. These manipulators, the so-called pecker probes, are two additional poloidal measurement points to the existing two (vertical and horizontal) reciprocating manipulators. The pecker probes are located at the low field side of COMPASS at ±47.5o with respect to the outer mid-plane and are equipped with identical tunnel probe heads, providing simultaneous measurements of the ion saturation current density Jsat, the electron temperature Te and the parallel Mach number M// with high temporal resolution. In this paper, a detailed description of the pecker probe system in COMPASS is described and first measurements are presented.

  8. Magnetic order in the two-dimensional compass-Heisenberg model

    NASA Astrophysics Data System (ADS)

    Vladimirov, Artem A.; Ihle, Dieter; Plakida, Nikolay M.

    2015-06-01

    A Green-function theory for the dynamic spin susceptibility in the square-lattice spin-1/2 antiferromagnetic compass-Heisenberg model employing a generalized mean-field approximation is presented. The theory describes magnetic long-range order (LRO) and short-range order (SRO) at arbitrary temperatures. The magnetization, Néel temperature TN, specific heat, and uniform static spin susceptibility χ are calculated self-consistently. As the main result, we obtain LRO at finite temperatures in two dimensions, where the dependence of TN on the compass-model interaction is studied. We find that TN is close to the experimental value for Ba2IrO4. The effects of SRO are discussed in relation to the temperature dependence of χ.

  9. Directional orientation of birds by the magnetic field under different light conditions.

    PubMed

    Wiltschko, Roswitha; Stapput, Katrin; Thalau, Peter; Wiltschko, Wolfgang

    2010-04-01

    This paper reviews the directional orientation of birds with the help of the geomagnetic field under various light conditions. Two fundamentally different types of response can be distinguished. (i) Compass orientation controlled by the inclination compass that allows birds to locate courses of different origin. This is restricted to a narrow functional window around the total intensity of the local geomagnetic field and requires light from the short-wavelength part of the spectrum. The compass is based on radical-pair processes in the right eye; magnetite-based receptors in the beak are not involved. Compass orientation is observed under 'white' and low-level monochromatic light from ultraviolet (UV) to about 565 nm green light. (ii) 'Fixed direction' responses occur under artificial light conditions such as more intense monochromatic light, when 590 nm yellow light is added to short-wavelength light, and in total darkness. The manifestation of these responses depends on the ambient light regime and is 'fixed' in the sense of not showing the normal change between spring and autumn; their biological significance is unclear. In contrast to compass orientation, fixed-direction responses are polar magnetic responses and occur within a wide range of magnetic intensities. They are disrupted by local anaesthesia of the upper beak, which indicates that the respective magnetic information is mediated by iron-based receptors located there. The influence of light conditions on the two types of response suggests complex interactions between magnetoreceptors in the right eye, those in the upper beak and the visual system.

  10. Directional orientation of birds by the magnetic field under different light conditions

    PubMed Central

    Wiltschko, Roswitha; Stapput, Katrin; Thalau, Peter; Wiltschko, Wolfgang

    2010-01-01

    This paper reviews the directional orientation of birds with the help of the geomagnetic field under various light conditions. Two fundamentally different types of response can be distinguished. (i) Compass orientation controlled by the inclination compass that allows birds to locate courses of different origin. This is restricted to a narrow functional window around the total intensity of the local geomagnetic field and requires light from the short-wavelength part of the spectrum. The compass is based on radical-pair processes in the right eye; magnetite-based receptors in the beak are not involved. Compass orientation is observed under ‘white’ and low-level monochromatic light from ultraviolet (UV) to about 565 nm green light. (ii) ‘Fixed direction’ responses occur under artificial light conditions such as more intense monochromatic light, when 590 nm yellow light is added to short-wavelength light, and in total darkness. The manifestation of these responses depends on the ambient light regime and is ‘fixed’ in the sense of not showing the normal change between spring and autumn; their biological significance is unclear. In contrast to compass orientation, fixed-direction responses are polar magnetic responses and occur within a wide range of magnetic intensities. They are disrupted by local anaesthesia of the upper beak, which indicates that the respective magnetic information is mediated by iron-based receptors located there. The influence of light conditions on the two types of response suggests complex interactions between magnetoreceptors in the right eye, those in the upper beak and the visual system. PMID:19864263

  11. Magnetic orientation of migratory robins, Erithacus rubecula, under long-wavelength light.

    PubMed

    Wiltschko, Roswitha; Denzau, Susanne; Gehring, Dennis; Thalau, Peter; Wiltschko, Wolfgang

    2011-09-15

    The avian magnetic compass is an inclination compass that appears to be based on radical pair processes. It requires light from the short-wavelength range of the spectrum up to 565 nm green light; under longer wavelengths, birds are disoriented. When pre-exposed to longer wavelengths for 1 h, however, they show oriented behavior. This orientation is analyzed under 582 nm yellow light and 645 nm red light in the present study: while the birds in spring prefer northerly directions, they do not show southerly tendencies in autumn. Inversion of the vertical component does not have an effect whereas reversal of the horizontal component leads to a corresponding shift, indicating that a polar response to the magnetic field is involved. Oscillating magnetic fields in the MHz range do not affect the behavior but anesthesia of the upper beak causes disorientation. This indicates that the magnetic information is no longer provided by the radical pair mechanism in the eye but by the magnetite-based receptors in the skin of the beak. Exposure to long-wavelength light thus does not expand the spectral range in which the magnetic compass operates but instead causes a different mechanism to take over and control orientation.

  12. 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; Oleś, 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.

  13. Electron spin relaxation can enhance the performance of a cryptochrome-based magnetic compass sensor

    NASA Astrophysics Data System (ADS)

    Kattnig, Daniel R.; Sowa, Jakub K.; Solov'yov, Ilia A.; Hore, P. J.

    2016-06-01

    The radical pair model of the avian magnetoreceptor relies on long-lived electron spin coherence. Dephasing, resulting from interactions of the spins with their fluctuating environment, is generally assumed to degrade the sensitivity of this compass to the direction of the Earth's magnetic field. Here we argue that certain spin relaxation mechanisms can enhance its performance. We focus on the flavin–tryptophan radical pair in cryptochrome, currently the only candidate magnetoreceptor molecule. Correlation functions for fluctuations in the distance between the two radicals in Arabidopsis thaliana cryptochrome 1 were obtained from molecular dynamics (MD) simulations and used to calculate the spin relaxation caused by modulation of the exchange and dipolar interactions. We find that intermediate spin relaxation rates afford substantial enhancements in the sensitivity of the reaction yields to an Earth-strength magnetic field. Supported by calculations using toy radical pair models, we argue that these enhancements could be consistent with the molecular dynamics and magnetic interactions in avian cryptochromes.

  14. Migration along orthodromic sun compass routes by arctic birds.

    PubMed

    Alerstam, T; Gudmundsson, G A; Green, M; Hedenstrom, A

    2001-01-12

    Flight directions of birds migrating at high geographic and magnetic latitudes can be used to test bird orientation by celestial or geomagnetic compass systems under polar conditions. Migration patterns of arctic shorebirds, revealed by tracking radar studies during an icebreaker expedition along the Northwest Passage in 1999, support predicted sun compass trajectories but cannot be reconciled with orientation along either geographic or magnetic loxodromes (rhumb lines). Sun compass routes are similar to orthodromes (great circle routes) at high latitudes, showing changing geographic courses as the birds traverse longitudes and their internal clock gets out of phase with local time. These routes bring the shorebirds from high arctic Canada to the east coast of North America, from which they make transoceanic flights to South America. The observations are also consistent with a migration link between Siberia and the Beaufort Sea region by way of sun compass routes across the Arctic Ocean. PMID:11209079

  15. Migration along orthodromic sun compass routes by arctic birds.

    PubMed

    Alerstam, T; Gudmundsson, G A; Green, M; Hedenstrom, A

    2001-01-12

    Flight directions of birds migrating at high geographic and magnetic latitudes can be used to test bird orientation by celestial or geomagnetic compass systems under polar conditions. Migration patterns of arctic shorebirds, revealed by tracking radar studies during an icebreaker expedition along the Northwest Passage in 1999, support predicted sun compass trajectories but cannot be reconciled with orientation along either geographic or magnetic loxodromes (rhumb lines). Sun compass routes are similar to orthodromes (great circle routes) at high latitudes, showing changing geographic courses as the birds traverse longitudes and their internal clock gets out of phase with local time. These routes bring the shorebirds from high arctic Canada to the east coast of North America, from which they make transoceanic flights to South America. The observations are also consistent with a migration link between Siberia and the Beaufort Sea region by way of sun compass routes across the Arctic Ocean.

  16. Microfluxgate sensor with amorphous cobalt (Co-Nb-Zr) soft magnetic core for electronic compass

    SciTech Connect

    Na, Kyoung-Won; Yuan, Jingli; Ji, Joon-Ho; Choi, Sang-On

    2006-04-15

    A silicon based microfluxgate sensor with a cobalt based amorphous soft magnetic core for electronic compass is presented in this paper. A sputtered Co{sub 85}Nb{sub 12}Zr{sub 3} magnetic core having a rectangular ring shape is combined with microcopper solenoid coils for excitation and pickup, which were wound alternately around the core to increase the number of coil turns. The Co{sub 85}Nb{sub 12}Zr{sub 3} as a core material is adopted for improving properties of the magnetic core and easy integration with micromachining processes to achieve a small size of the sensor. The sputtered Co{sub 85}Nb{sub 12}Zr{sub 3} showed dc effective permeability of {approx}10 000 and an extremely low coercivity of {approx}0.03 Oe with the thickness of 1 {mu}m. The Co{sub 85}Nb{sub 12}Zr{sub 3} as a thin film core with high permeability and low coercivity was easily saturated by a low excitation magnetic field, enhancing the sensitivity and linearity of the microfluxgate sensor. Finally, the sensor showed excellent linearity response over the range of -300 to 300 {mu}T with sensitivity of 60 V/T at the excitation condition of 3.0 V{sub p-p} and 5.0 MHz square wave form. The sensor size excluding pad region is about 0.55x1.4 mm{sup 2}.

  17. 46 CFR 28.230 - Compasses.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Compasses. 28.230 Section 28.230 Shipping COAST GUARD... Board, or for Fish Tender Vessels Engaged in the Aleutian Trade § 28.230 Compasses. Each vessel must be equipped with an operable magnetic steering compass with a compass deviation table at the operating station....

  18. 46 CFR 28.230 - Compasses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Compasses. 28.230 Section 28.230 Shipping COAST GUARD... Board, or for Fish Tender Vessels Engaged in the Aleutian Trade § 28.230 Compasses. Each vessel must be equipped with an operable magnetic steering compass with a compass deviation table at the operating station....

  19. 46 CFR 28.230 - Compasses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Compasses. 28.230 Section 28.230 Shipping COAST GUARD... Board, or for Fish Tender Vessels Engaged in the Aleutian Trade § 28.230 Compasses. Each vessel must be equipped with an operable magnetic steering compass with a compass deviation table at the operating station....

  20. 46 CFR 28.230 - Compasses.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Compasses. 28.230 Section 28.230 Shipping COAST GUARD... Board, or for Fish Tender Vessels Engaged in the Aleutian Trade § 28.230 Compasses. Each vessel must be equipped with an operable magnetic steering compass with a compass deviation table at the operating station....

  1. 46 CFR 28.230 - Compasses.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Compasses. 28.230 Section 28.230 Shipping COAST GUARD... Board, or for Fish Tender Vessels Engaged in the Aleutian Trade § 28.230 Compasses. Each vessel must be equipped with an operable magnetic steering compass with a compass deviation table at the operating station....

  2. Ethical advantages of using domestic bird species for magnetic orientation research.

    PubMed

    Freire, Rafael

    2011-01-01

    Identifying the mechanism in birds that controls magnetic orientation behavior is proving elusive and is currently attracting a plethora of research activity. Much of this research involves wild birds that are caught in nets, tested and released. Ethical concerns regarding these experiments are likely to encompass the welfare of animals, their "rights" and conservation issues. Recently, Pekin ducks derived from migratory ancestors have been shown to posses a magnetic compass in a simple conditioning procedure. The use of domestic bird species provides a refinement in the ethics of animal experimentation since these birds are not caught in nets, are less fearful of humans and their use does not raise conservation concerns. The study of magnetic orientation is a high profile and fascinating areas of animal behavior research and one in which behavioral scientists should be seen to actively embrace the principles of the 3R's.

  3. How do honeybees use their magnetic compass? Can they see the North?

    PubMed

    Válková, T; Vácha, M

    2012-08-01

    While seeking food sources and routes back to their hive, bees make use of their advanced nervous and sensory capacities, which underlie a diverse behavioral repertoire. One of several honeybee senses that is both exceptional and intriguing is magnetoreception - the ability to perceive the omnipresent magnetic field (MF) of the Earth. The mechanism by which animals sense MFs has remained fascinating as well as elusive because of the intricacies involved, which makes it one of the grand challenges for neural and sensory biology. However, investigations in recent years have brought substantial progress to our understanding of how such magneto-receptor(s) may work. Some terrestrial animals (birds) are reported to be equipped even with a dual perception system: one based on diminutive magnetic particles - in line with the original model which has also always been hypothesized for bees - and the other one, as the more recent model describes, based on a sensitivity of some photochemical reactions to MF (radical-pair or chemical mechanism). The latter model postulates a close link to vision and supposes that the animals can see the position of the geomagnetic North as a visible pattern superimposed on the picture of the environment. In recent years, a growing body of evidence has shown that radical-pair magnetoreception might also be used by insects. It is realistic to expect that such evidence will inspire a re-examination and extension or confirmation of established views on the honeybee magnetic-compass mechanism. However, the problem of bee magnetoreception will not be solved at the moment that a receptor is discovered. On the contrary, the meaning of magnetoreception in insect life and its involvement in the orchestration of other senses is yet to be fully understood. The crucial question to be addressed in the near future is whether the compass abilities of the honeybee could suffer from radio frequency (RF) smog accompanying modern civilization and whether the

  4. Magnetoreception: activated cryptochrome 1a concurs with magnetic orientation in birds.

    PubMed

    Nießner, Christine; Denzau, Susanne; Stapput, Katrin; Ahmad, Margaret; Peichl, Leo; Wiltschko, Wolfgang; Wiltschko, Roswitha

    2013-11-01

    The radical pair model proposes that the avian magnetic compass is based on radical pair processes in the eye, with cryptochrome, a flavoprotein, suggested as receptor molecule. Cryptochrome 1a (Cry1a) is localized at the discs of the outer segments of the UV/violet cones of European robins and chickens. Here, we show the activation characteristics of a bird cryptochrome in vivo under natural conditions. We exposed chickens for 30 min to different light regimes and analysed the amount of Cry1a labelled with an antiserum against an epitope at the C-terminus of this protein. The staining after exposure to sunlight and to darkness indicated that the antiserum labels only an illuminated, activated form of Cry1a. Exposure to narrow-bandwidth lights of various wavelengths revealed activated Cry1a at UV, blue and turquoise light. With green and yellow, the amount of activated Cry1a was reduced, and with red, as in the dark, no activated Cry1a was labelled. Activated Cry1a is thus found at all those wavelengths at which birds can orient using their magnetic inclination compass, supporting the role of Cry1a as receptor molecule. The observation that activated Cry1a and well-oriented behaviour occur at 565 nm green light, a wavelength not absorbed by the fully oxidized form of cryptochrome, suggests that a state other than the previously suggested Trp/FAD radical pair formed during photoreduction is crucial for detecting magnetic directions.

  5. Magnetoreception: activated cryptochrome 1a concurs with magnetic orientation in birds.

    PubMed

    Nießner, Christine; Denzau, Susanne; Stapput, Katrin; Ahmad, Margaret; Peichl, Leo; Wiltschko, Wolfgang; Wiltschko, Roswitha

    2013-11-01

    The radical pair model proposes that the avian magnetic compass is based on radical pair processes in the eye, with cryptochrome, a flavoprotein, suggested as receptor molecule. Cryptochrome 1a (Cry1a) is localized at the discs of the outer segments of the UV/violet cones of European robins and chickens. Here, we show the activation characteristics of a bird cryptochrome in vivo under natural conditions. We exposed chickens for 30 min to different light regimes and analysed the amount of Cry1a labelled with an antiserum against an epitope at the C-terminus of this protein. The staining after exposure to sunlight and to darkness indicated that the antiserum labels only an illuminated, activated form of Cry1a. Exposure to narrow-bandwidth lights of various wavelengths revealed activated Cry1a at UV, blue and turquoise light. With green and yellow, the amount of activated Cry1a was reduced, and with red, as in the dark, no activated Cry1a was labelled. Activated Cry1a is thus found at all those wavelengths at which birds can orient using their magnetic inclination compass, supporting the role of Cry1a as receptor molecule. The observation that activated Cry1a and well-oriented behaviour occur at 565 nm green light, a wavelength not absorbed by the fully oxidized form of cryptochrome, suggests that a state other than the previously suggested Trp/FAD radical pair formed during photoreduction is crucial for detecting magnetic directions. PMID:23966619

  6. 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

  7. Magnetic material arrangement in oriented termites: a magnetic resonance study

    NASA Astrophysics Data System (ADS)

    Alves, O. C.; Wajnberg, E.; de Oliveira, J. F.; Esquivel, D. M. S.

    2004-06-01

    Temperature dependence of the magnetic resonance is used to study the magnetic material in oriented Neocapritermes opacus (N.o.) termite, the only prey of the migratory ant Pachycondyla marginata (P.m.). A broad line in the g=2 region, associated to isolated nanoparticles shows that at least 97% of the magnetic material is in the termite's body (abdomen + thorax). From the temperature dependence of the resonant field and from the spectral linewidths, we estimate the existence of magnetic nanoparticles 18.5 ± 0.3 nm in diameter and an effective magnetic anisotropy constant, Keff between 2.1 and 3.2 × 10 4 erg/cm 3. A sudden change in the double integrated spectra at about 100 K for N.o. with the long body axis oriented perpendicular to the magnetic field can be attributed to the Verwey transition, and suggests an organized film-like particle system.

  8. 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

  9. Cryptochromes and neuronal-activity markers colocalize in the retina of migratory birds during magnetic orientation.

    PubMed

    Mouritsen, Henrik; Janssen-Bienhold, Ulrike; Liedvogel, Miriam; Feenders, Gesa; Stalleicken, Julia; Dirks, Petra; Weiler, Reto

    2004-09-28

    Migratory birds can use a magnetic compass for orientation during their migratory journeys covering thousands of kilometers. But how do they sense the reference direction provided by the Earth's magnetic field? Behavioral evidence and theoretical considerations have suggested that radical-pair processes in differently oriented, light-sensitive molecules of the retina could enable migratory birds to perceive the magnetic field as visual patterns. The cryptochromes (CRYs) have been suggested as the most likely candidate class of molecules, but do CRYs exist in the retina of migratory birds? Here, we show that at least one CRY1 and one CRY2 exist in the retina of migratory garden warblers and that garden-warbler CRY1 (gwCRY1) is cytosolic. We also show that gwCRY1 is concentrated in specific cells, particularly in ganglion cells and in large displaced ganglion cells, which also showed high levels of neuronal activity at night, when our garden warblers performed magnetic orientation. In addition, there seem to be striking differences in CRY1 expression between migratory and nonmigratory songbirds at night. The difference in CRY1 expression between migrants and nonmigrants is particularly pronounced in the large displaced ganglion cells known to project exclusively to a brain area where magnetically sensitive neurons have been reported. Consequently, cytosolic gwCRY1 is well placed to possibly be the primary magnetic-sensory molecule required for light-mediated magnetoreception. PMID:15381765

  10. Coupled solar-magnetic orientation during leatherback turtle (Dermochelys coriacea), great white shark (Carcharodon carcharias), arctic tern (Sterna paradisaea), and humpback whale (Megaptera novaeangliae) long-distance migration

    NASA Astrophysics Data System (ADS)

    Horton, T. W.; Holdaway, R. N.; Zerbini, A.; Andriolo, A.; Clapham, P. J.

    2010-12-01

    Determining how animals perform long-distance animal migration remains one of the most enduring and fundamental mysteries of behavioural ecology. It is widely accepted that navigation relative to a reference datum is a fundamental requirement of long-distance return migration between seasonal habitats, and significant experimental research has documented a variety of viable orientation and navigation cues. However, relatively few investigations have attempted to reconcile experimentally determined orientation and navigation capacities of animals with empirical remotely sensed animal track data, leaving most theories of navigation and orientation untested. Here we show, using basic hypothesis testing, that leatherback turtle (Dermochelys coriacea), great white shark (Carcharodon carcharias), arctic tern (Sterna paradisaea), and humpback whale (Megaptera novaeangliae) migration paths are non-randomly distributed in magnetic coordinate space, with local peaks in magnetic coordinate distributions equal to fractional multiples of the angular obliquity of Earth’s axis of rotation. Time series analysis of humpback whale migratory behaviours, including migration initiation, changes in course, and migratory stop-overs, further demonstrate coupling of magnetic and celestial orientation cues during long-distance migration. These unexpected and highly novel results indicate that diverse taxa integrate magnetic and celestial orientation cues during long-distance migration. These results are compatible with a 'map and compass' orientation and navigation system. Humpback whale migration track geometries further indicate a map and compass orientation system is used. Several humpback whale tracks include highly directional segments (Mercator latitude vs. longitude r2>0.99) exceeding 2000 km in length, despite exposure to variable strength (c. 0-1 km/hr) surface cross-currents. Humpback whales appear to be able to compensate for surface current drift. The remarkable directional

  11. 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 τixτjx (where {τia}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 τiyτjy 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

  12. 46 CFR 121.402 - Compasses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... be fitted with a suitable magnetic compass designed for marine use, to be mounted at the primary operating station. (b) The following vessels need not be fitted with a compass: (1) A vessel on a rivers..., bays, and sounds. (c) Except on a vessel limited to daytime operations, the compass must be illuminated....

  13. 46 CFR 184.402 - Compasses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... in this section every vessel must be fitted with a suitable magnetic compass designed for marine use... compass: (1) A vessel on a rivers route; (2) A non-self propelled vessel; and (3) A vessel operating on..., the compass must be illuminated....

  14. 46 CFR 184.402 - Compasses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... in this section every vessel must be fitted with a suitable magnetic compass designed for marine use... compass: (1) A vessel on a rivers route; (2) A non-self propelled vessel; and (3) A vessel operating on..., the compass must be illuminated....

  15. 46 CFR 184.402 - Compasses.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... in this section every vessel must be fitted with a suitable magnetic compass designed for marine use... compass: (1) A vessel on a rivers route; (2) A non-self propelled vessel; and (3) A vessel operating on..., the compass must be illuminated....

  16. 46 CFR 184.402 - Compasses.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... in this section every vessel must be fitted with a suitable magnetic compass designed for marine use... compass: (1) A vessel on a rivers route; (2) A non-self propelled vessel; and (3) A vessel operating on..., the compass must be illuminated....

  17. 46 CFR 121.402 - Compasses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... be fitted with a suitable magnetic compass designed for marine use, to be mounted at the primary operating station. (b) The following vessels need not be fitted with a compass: (1) A vessel on a rivers..., bays, and sounds. (c) Except on a vessel limited to daytime operations, the compass must be illuminated....

  18. 46 CFR 184.402 - Compasses.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... in this section every vessel must be fitted with a suitable magnetic compass designed for marine use... compass: (1) A vessel on a rivers route; (2) A non-self propelled vessel; and (3) A vessel operating on..., the compass must be illuminated....

  19. 46 CFR 121.402 - Compasses.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... be fitted with a suitable magnetic compass designed for marine use, to be mounted at the primary operating station. (b) The following vessels need not be fitted with a compass: (1) A vessel on a rivers..., bays, and sounds. (c) Except on a vessel limited to daytime operations, the compass must be illuminated....

  20. Sensitivity and entanglement in the avian chemical compass.

    PubMed

    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.

  1. 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.

  2. Sensitivity and entanglement in the avian chemical compass.

    PubMed

    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. PMID:25375523

  3. The magnetic orientation of the Antarctic amphipod Gondogeneia antarctica is cancelled by very weak radiofrequency fields.

    PubMed

    Tomanova, K; Vacha, M

    2016-06-01

    Studies on weak man-made radiofrequency (RF) electromagnetic fields affecting animal magnetoreception aim for a better understanding of the reception mechanism and also point to a new phenomenon having possible consequences in ecology and environmental protection. RF impacts on magnetic compasses have recently been demonstrated in migratory birds and other vertebrates. We set out to investigate the effect of RF on the magnetic orientation of the Antarctic krill species Gondogeneia antarctica, a small marine crustacean widespread along the Antarctic littoral line. Here, we show that upon release, G. antarctica (held under laboratory conditions) escaped in the magnetically seaward direction along the magnetic sea-land axis (y-axis) of the home beach. However, the animals were disoriented after being exposed to RF. Orientation was lost not only in an RF field with a magnetic flux density of 20 nT, as expected according to the literature, but even under the 2 nT originally intended as a control. Our results extend recent findings of the extraordinary sensitivity of animal magnetoreception to weak RF fields in marine invertebrates.

  4. Seismic cable compass system

    SciTech Connect

    Burrage, E.C.

    1984-11-06

    An apparatus for determining the azimuthal direction of a marine streamer cable at selected points along the cable. The apparatus comprises a pod that is clamped to the cable and contains a gimbaled magnetic compass and mean for establishing two-way communication between the pod and the cable.

  5. Self-compassion and social anxiety disorder.

    PubMed

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

    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, we tested the hypotheses that: (1) people with SAD would demonstrate less self-compassion than healthy controls (HCs), (2) self-compassion would relate to severity of social anxiety and fear of evaluation among people with SAD, and (3) age would be negatively correlated with self-compassion for people with SAD, but not for HC. As expected, people with SAD reported less self-compassion than HCs on the Self-Compassion Scale and its subscales. Within the SAD group, lesser self-compassion was not generally associated with severity of social anxiety, but it was associated with greater fear of both negative and positive evaluation. Age was negatively correlated with self-compassion for people with SAD, whereas age was positively correlated with self-compassion for HC. These findings suggest that self-compassion may be a particularly important target for assessment and treatment in persons with SAD.

  6. 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)

  7. The orientation and navigation of juvenile alligators: evidence of magnetic sensitivity

    USGS Publications Warehouse

    Rodda, Gordon H.

    1984-01-01

    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 sites. When displaced by a circuitous route, yearlings failed to compensate for their displacement, exhibiting instead simple compass orientation in a direction that would have returned them to water had they been released on land near the site where they were captured. The older juveniles were oriented in a homeward direction under all displacement and test conditions. The latter animals may have been using geomagnetic map information to select their homeward directions as the errors in their homeward bearings correlated with small deviations in the geomagnetic field's dip angle at the time of the test (1980r s=−0.6047,P=0.0131, all testsr s= −0.4652,P=0.0084). This effect appeared to depend on a very short-term assessment of geomagnetic conditions, as values measured 20 min before or 30 min after the tests began did not correlate with the directions the animals moved. The older juveniles appeared to use magnetically quiet hours on the night of their capture as the baseline from which to measure the geomagnetic deviations that occurred at the time of the arena test. The magnitude of the magnetic effect in the older animals suggests that the geomagnetic information may have been used to perform a ‘map’ step, as small fluctuations in dip angle correlated with much larger deviations in homeward bearings. In addition, the compass-oriented yearlings and the seemingly route-based behavior of the homeward-oriented yearlings did not appear to be influenced by geomagnetic conditions. These findings have many parallels in results obtained from bird orientation studies

  8. Computational Modeling of Magnetically Actuated Propellant Orientation

    NASA Technical Reports Server (NTRS)

    Hochstein, John I.

    1996-01-01

    Unlike terrestrial applications where gravity positions liquid at the "bottom" of the tank, the location of liquid propellant in spacecraft tanks is uncertain unless specific actions are taken or special features are built into the tank. Some mission events require knowledge of liquid position prior to a particular action: liquid must be positioned over the tank outlet prior to starting the main engines and must be moved away from the tank vent before vapor can be released overboard to reduce pressure. It may also be desirable to positively position liquid to improve propulsion system performance: moving liquid away from the tank walls will dramatically decrease the rate of heat transfer to the propellant, suppressing the boil-off rate, thereby reducing overall mission propellant requirements. The process of moving propellant to a desired position is referred to as propellant orientation or reorientation. Propulsive reorientation relies on small auxiliary thrusters to accelerate the tank. The inertia of the liquid causes it to collect in the aft-end of the tank if the acceleration is forward. Liquid Acquisition Devices (LAD's) rely on surface tension to hold the liquid within special geometries, (i.e. vanes, wire-mesh channels, start-baskets), to positively position propellants. Both of these technologies add significant weight and complexity to the spacecraft and can be limiting systems for long duration missions. The subject of the present research is an alternate technique for positively positioning liquid within spacecraft propellant tanks: magnetic fields. LOX is paramagnetic (attracted toward a magnet) and LH2 is diamagnetic (repelled from a magnet). Order-of-magnitude analyses, performed in the 1960's to determine required magnet size, concluded that the magnets would be prohibitively massive and this option has remained dormant during the intervening years. Recent advances in high-temperature superconducting materials hold the promise of electromagnets with

  9. Computational modeling of magnetically actuated propellant orientation

    NASA Technical Reports Server (NTRS)

    Hochstein, John I.

    1996-01-01

    Unlike terrestrial applications where gravity positions liquid at the 'bottom' of the tank, the location of liquid propellant in spacecraft tanks is uncertain unless specific actions are taken or special features are built into the tank. Some mission events require knowledge of liquid position prior to a particular action: liquid must be positioned over the tank outlet prior to starting the main engines and must be moved away from the tank vent before vapor can be released overboard to reduce pressure. It may also be desirable to positively position liquid to improve propulsion system performance: moving liquid away from the tank walls will dramatically decrease the rate of heat transfer to the propellant, suppressing the boil-off rate, thereby reducing overall mission propellant requirements. The process of moving propellant to a desired position is referred to as propellant orientation or reorientation. Several techniques have been developed to positively position propellant in spacecraft tanks and each technique imposes additional requirements on vehicle design. Propulsive reorientation relies on small auxiliary thrusters to accelerate the tank. The inertia of the liquid causes it to collect in the aft-end of the tank if the acceleration is forward. This technique requires that additional thrusters be added to the vehicle, that additional propellant be carried in the vehicle, and that an additional operational maneuver be executed. Another technique uses Liquid Acquisition Devices (LAD's) to positively position propellants. These devices rely on surface tension to hold the liquid within special geometries (i.e. vanes, wire-mesh channels, start-baskets). While avoiding some of the penalties of propulsive orientation, this technique requires the addition of complicated hardware inside the propellant tank and performance for long duration missions is uncertain. The subject of the present research is an alternate technique for positively positioning liquid within

  10. Lunar Compass: A Rover Mission for Exploration of a Lunar Crustal Magnetic Anomaly

    NASA Astrophysics Data System (ADS)

    Blewett, D. T.; Hurley, D. M.; Denevi, B. W.; Cahill, J. T. S.; Klima, R. L.; Plescia, J. B.; Paranicas, C. P.; Greenhagen, B. T.; Anderson, B. A.; Korth, H.; Ho, G. C.; Nunez, J. I.; Zimmerman, M. I.; Brandt, P. C.

    2016-11-01

    We suggest that a rover mission to a lunar magnetic anomaly could answer key questions in several major fields of planetary science: planetary magnetism, space plasma physics, lunar geology, and space weathering.

  11. 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.

  12. 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

  13. Ambulatory position and orientation tracking fusing magnetic and inertial sensing.

    PubMed

    Roetenberg, Daniel; Slycke, Per J; Veltink, Peter H

    2007-05-01

    This paper presents the design and testing of a portable magnetic system combined with miniature inertial sensors for ambulatory 6 degrees of freedom (DOF) human motion tracking. The magnetic system consists of three orthogonal coils, the source, fixed to the body and 3-D magnetic sensors, fixed to remote body segments, which measure the fields generated by the source. Based on the measured signals, a processor calculates the relative positions and orientations between source and sensor. Magnetic actuation requires a substantial amount of energy which limits the update rate with a set of batteries. Moreover, the magnetic field can easily be disturbed by ferromagnetic materials or other sources. Inertial sensors can be sampled at high rates, require only little energy and do not suffer from magnetic interferences. However, accelerometers and gyroscopes can only measure changes in position and orientation and suffer from integration drift. By combing measurements from both systems in a complementary Kalman filter structure, an optimal solution for position and orientation estimates is obtained. The magnetic system provides 6 DOF measurements at a relatively low update rate while the inertial sensors track the changes position and orientation in between the magnetic updates. The implemented system is tested against a lab-bound camera tracking system for several functional body movements. The accuracy was about 5 mm for position and 3 degrees for orientation measurements. Errors were higher during movements with high velocities due to relative movement between source and sensor within one cycle of magnetic actuation. PMID:17518285

  14. Remotely readable fiber optic compass

    DOEpatents

    Migliori, A.; Swift, G.W.; Garrett, S.L.

    1985-04-30

    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.

  15. Remotely readable fiber optic compass

    DOEpatents

    Migliori, Albert; Swift, Gregory W.; Garrett, Steven L.

    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.

  16. 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

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

    SciTech Connect

    Roy, Debangsu Anil Kumar, P. S.

    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.

  18. Self-Compassion among College Counseling Center Clients: An Examination of Clinical Norms and Group Differences

    ERIC Educational Resources Information Center

    Lockard, Allison J.; Hayes, Jeffrey A.; Neff, Kristin; Locke, Benjamin D.

    2014-01-01

    There has been growing interest in the mental health benefits of self-compassion. This study was designed to establish norms on the Self-Compassion Scale-Short Form, a popular measure of self-compassion for individuals seeking counseling, and to examine group differences in self-compassion based on gender, race/ethnicity, sexual orientation,…

  19. 46 CFR 169.709 - Compass.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Compass. 169.709 Section 169.709 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Vessel Control, Miscellaneous Systems, and Equipment § 169.709 Compass. (a) Each vessel must be fitted with a magnetic...

  20. 46 CFR 169.709 - Compass.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Compass. 169.709 Section 169.709 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Vessel Control, Miscellaneous Systems, and Equipment § 169.709 Compass. (a) Each vessel must be fitted with a magnetic...

  1. Determination of orientational order parameters from 2H NMR spectra of magnetically partially oriented lipid bilayers.

    PubMed Central

    Schäfer, H; Mädler, B; Sternin, E

    1998-01-01

    The partial orientation of multilamellar vesicles (MLVs) in high magnetic fields is known to affect the shape of 2H NMR spectra. There are numerical methods for extracting either the orientational order parameters of lipid molecules for a random distribution of domain orientations in the sample, or the distribution of orientations for a known set of spectral anisotropies. A first attempt at determining the orientational order parameters in the presence of an unknown nonrandom distribution of orientations is presented. The numerical method is based on the Tikhonov regularization algorithm. It is tested using simulated partially oriented spectra. An experimental spectrum of a phospholipid-ether mixture in water is analyzed as an example. The experimental spectrum is consistent with an ellipsoidal shape of MLVs with a ratio of semiaxes of approximately 3.4. PMID:9533713

  2. Tracing magnetic field orientation in starless cores

    NASA Astrophysics Data System (ADS)

    Maheswar, G.; Ramaprakash, A. N.; Lee, C. W.; Dib, S.

    It is now well understood that stars are formed in the interiors of dense, gravitationally bound molecular cloud cores that are both magnetized and turbulent. But the relative role played by the magnetic field and the turbulence in cloud formation and evolution and in the subsequent star formation is a matter of debate. In a magnetically dominated scenario, the magnetic field geometry of the cores is expected to be inherited unchanged from their low-density envelope, even for an hour glass geometry of the field, unless the action of turbulence disturbs it. We carried out polarimetry of stars projected on starless molecular clouds, LDN 183 and LDN 1544, in R-filter. The comparison of these fields with those in the interiors of the cloud cores inferred from the sub-mm polarization shows that both magnetic field and turbulence are important in the cloud formation and evolution of star formation.

  3. Orienting Paramecium with intense static magnetic fields

    NASA Astrophysics Data System (ADS)

    Valles, James M., Jr.; Guevorkian, Karine; Quindel, Carl

    2004-03-01

    Recent experiments on cell division suggest the application of intense static magnetic fields as a novel tool for the manipulation of biological systems [1]. The magnetic field appears to couple to the intrinsic anisotropies in the diamagnetic components of the cells. Here, we present measurements of the intrinsic average diamagnetic anisotropy of the whole single celled ciliate, Paramecium Caudatum. Magnetic fields, 2.5 T < B < 8 T were applied to immobilized (non-swimming) Paramecium Caudatum that were suspended in a density matched medium. The organisms align with their long axis parallel to the applied magnetic field. Their intrinsic diamagnetic anisotropy is 3x10-11 in cgs units. We will discuss the implications of these results for employing magnetic fields to probe the behavior of swimming Paramecium. [1] J. M. Valles, Jr. et al., Expt. Cell Res.274, 112-118 (2002).

  4. Deflection of the Interstellar Neutral Hydrogen Flow Across the Heliospheric Interface: an Interstellar Magnetic Compass

    NASA Astrophysics Data System (ADS)

    Lallement, R.; Eric, Q.; Jean-Loup, B.; Dimitra, K.; Risto, P.

    2005-05-01

    Analyses of SOHO-SWAN observations show that the interstellar neutral H flow direction differs by about 4 degrees from the neutral He flow direction recently derived with an unprecedented accuracy using combined data sets (Mobius et al, 2004). The most likely explanation is a distortion of the heliospheric interface under the action of an inclined interstellar magnetic field, with imprints of the distorsion on the neutral H flow due to charge-transfer reactions between H atoms and ions. The direction of the ambient interstellar magnetic field and the heliospheric shape can be derived from the observed deviation. Implications for Voyager trajectories are discussed.

  5. 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...

  6. 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…

  7. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

    Several experiments over the years have shown that the 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. In order to define a reference frame for the orientation task radicals must have an intrinsic anisotropy. 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. Even a dephasing environment can provide the necessary frame for the compass to work and also implies fast decay of any quantum correlation in the system without damaging the orientation ability. This fact significantly expands the range of applicability of the RP mechanism providing more elements for experimental search.

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

    PubMed

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

    2015-07-01

    Several experiments over the years have shown that the 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. In order to define a reference frame for the orientation task radicals must have an intrinsic anisotropy. 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. Even a dephasing environment can provide the necessary frame for the compass to work and also implies fast decay of any quantum correlation in the system without damaging the orientation ability. This fact significantly expands the range of applicability of the RP mechanism providing more elements for experimental search.

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

    PubMed

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

    2015-07-01

    Several experiments over the years have shown that the 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. In order to define a reference frame for the orientation task radicals must have an intrinsic anisotropy. 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. Even a dephasing environment can provide the necessary frame for the compass to work and also implies fast decay of any quantum correlation in the system without damaging the orientation ability. This fact significantly expands the range of applicability of the RP mechanism providing more elements for experimental search. PMID:26274215

  11. Conditioned discrimination of magnetic inclination in a spatial-orientation arena task by homing pigeons (Columba livia).

    PubMed

    Mora, Cordula V; Acerbi, Merissa L; Bingman, Verner P

    2014-12-01

    It has been well established that homing pigeons are able to use the Earth's magnetic field to obtain directional information when returning to their loft and that their magnetic compass is based, at least in part, on the perception of magnetic inclination. Magnetic inclination has also been hypothesized in pigeons and other long-distance navigators, such as sea turtles, to play a role providing positional information as part of a map. Here we developed a behavioral paradigm which allows us to condition homing pigeons to discriminate magnetic inclination cues in a spatial-orientation arena task. Six homing pigeons were required to discriminate in a circular arena between feeders located either in a zone with a close to 0 deg inclination cue or in a zone with a rapidly changing inclination cue (-3 deg to +85 deg when approaching the feeder and +85 deg to -3 deg when moving away from the feeder) to obtain a food reward. The pigeons consistently performed this task above chance level. Control experiments, during which the coils were turned off or the current was running anti-parallel through the double-wound coil system, confirmed that no alternative cues were used by the birds in the discrimination task. The results show that homing pigeons can be conditioned to discriminate differences in magnetic field inclination, enabling investigation into the peripheral and central neural processing of geomagnetic inclination under controlled laboratory conditions. PMID:25278470

  12. Conditioned discrimination of magnetic inclination in a spatial-orientation arena task by homing pigeons (Columba livia).

    PubMed

    Mora, Cordula V; Acerbi, Merissa L; Bingman, Verner P

    2014-12-01

    It has been well established that homing pigeons are able to use the Earth's magnetic field to obtain directional information when returning to their loft and that their magnetic compass is based, at least in part, on the perception of magnetic inclination. Magnetic inclination has also been hypothesized in pigeons and other long-distance navigators, such as sea turtles, to play a role providing positional information as part of a map. Here we developed a behavioral paradigm which allows us to condition homing pigeons to discriminate magnetic inclination cues in a spatial-orientation arena task. Six homing pigeons were required to discriminate in a circular arena between feeders located either in a zone with a close to 0 deg inclination cue or in a zone with a rapidly changing inclination cue (-3 deg to +85 deg when approaching the feeder and +85 deg to -3 deg when moving away from the feeder) to obtain a food reward. The pigeons consistently performed this task above chance level. Control experiments, during which the coils were turned off or the current was running anti-parallel through the double-wound coil system, confirmed that no alternative cues were used by the birds in the discrimination task. The results show that homing pigeons can be conditioned to discriminate differences in magnetic field inclination, enabling investigation into the peripheral and central neural processing of geomagnetic inclination under controlled laboratory conditions.

  13. Chemical Compass Model for Avian Magnetoreception as a Quantum Coherent Device

    NASA Astrophysics Data System (ADS)

    Cai, Jianming; Plenio, Martin B.

    2013-12-01

    It is known that more than 50 species use the Earth’s magnetic field for orientation and navigation. Intensive studies, particularly behavior experiments with birds, provide support for a chemical compass based on magnetically sensitive free radical reactions as a source of this sense. However, the fundamental question of how quantum coherence plays an essential role in such a chemical compass model of avian magnetoreception yet remains controversial. Here, we show that the essence of the chemical compass model can be understood in analogy to a quantum interferometer exploiting global quantum coherence rather than any subsystem coherence. Within the framework of quantum metrology, we quantify global quantum coherence and correlate it with the function of chemical magnetoreception. Our results allow us to understand and predict how various factors can affect the performance of a chemical compass from the unique perspective of quantum coherence assisted metrology. This represents a crucial step to affirm a direct connection between quantum coherence and the function of a chemical compass.

  14. Chemical compass model for avian magnetoreception as a quantum coherent device.

    PubMed

    Cai, Jianming; Plenio, Martin B

    2013-12-01

    It is known that more than 50 species use the Earth's magnetic field for orientation and navigation. Intensive studies, particularly behavior experiments with birds, provide support for a chemical compass based on magnetically sensitive free radical reactions as a source of this sense. However, the fundamental question of how quantum coherence plays an essential role in such a chemical compass model of avian magnetoreception yet remains controversial. Here, we show that the essence of the chemical compass model can be understood in analogy to a quantum interferometer exploiting global quantum coherence rather than any subsystem coherence. Within the framework of quantum metrology, we quantify global quantum coherence and correlate it with the function of chemical magnetoreception. Our results allow us to understand and predict how various factors can affect the performance of a chemical compass from the unique perspective of quantum coherence assisted metrology. This represents a crucial step to affirm a direct connection between quantum coherence and the function of a chemical compass. PMID:24476240

  15. COMPASS Overview

    SciTech Connect

    Magnon, A.

    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.

  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. Orientation of the X-line in asymmetric magnetic reconnection

    NASA Astrophysics Data System (ADS)

    Aunai, N.; Hesse, M.; Lavraud, B.; Dargent, J.; Smets, R.

    2016-08-01

    > Magnetic reconnection can occur in current sheets separating magnetic fields sheared by any angle and of arbitrarily different amplitudes. In such asymmetric and non-coplanar systems, it is not yet understood what the orientation of the X-line will be. Studying how this orientation is determined locally by the reconnection process is important to understand systems such as the Earth magnetopause, where reconnection occurs in regions with large differences in upstream plasma and field properties. This study aims at determining what the local X-line orientation is for different upstream magnetic shear angles in an asymmetric set-up relevant to the Earth's magnetopause. We use two-dimensional hybrid simulations and vary the simulation plane orientation with regard to the fixed magnetic field profile and search for the plane maximizing the reconnection rate. We find that the plane defined by the bisector of upstream fields maximizes the reconnection rate and this appears not to depend on the magnetic shear angle, domain size or upstream plasma and asymmetries.

  18. Crystallographic orientation variation of isothermal pearlite under high magnetic field

    SciTech Connect

    Meng, Lan Zhou, Xiaoling Chen, Jianhao

    2015-07-15

    Crystallographic orientation (CO) variation of magnetic-induced pearlite (MIP) during its microstructure evolution in 19.8 T was investigated by electron back-scatter diffraction (EBSD). It is closely related to the isothermal temperatures (ITs) and the applied magnetic time (MT) during the process of MIP formation. The <100> easy magnetization direction in MIP colonies is strengthened with the MT within the certain transformed fraction of MIP (f{sub MIP}) at the relatively lower IT (983 K) above the eutectoid temperature but below the magnetically shifted upward eutectoid temperature, while this special CO tends to be weakened at a relatively higher IT (995 K). For the same MT, the higher the IT, the relatively larger is the proportion in <100> orientation for MIP colonies at the early growth stage. These results have demonstrated that the change of <100> orientation of MIP is closely related to the growth rate of pearlite ferrite (PF), and strengthened mainly at early transformation stage. When f{sub MIP} reaches some value, the growth rate of MIP at other COs, such as <110>, even at the hard magnetization direction, turns to present speed-up. - Highlights: • HMF can induce pearlite with different fractions above the eutectoid temperature. • CO is closely related to isothermal temperatures and applied magnetic time. • <100> direction is related to the growth rate of PF, and strengthened at early stage. • When f{sub MIP} reaches some value, the growth rate at other COs turns to present speed-up.

  19. 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

  20. Field orientation dependence of magnetization reversal in thin films with perpendicular magnetic anisotropy

    NASA Astrophysics Data System (ADS)

    Fallarino, Lorenzo; Hovorka, Ondrej; Berger, Andreas

    2016-08-01

    The magnetization reversal process of hexagonal-close-packed (hcp) (0001) oriented Co and C o90R u10 thin films with perpendicular magnetic anisotropy (PMA) has been studied as a function of temperature and applied magnetic field angle. Room temperature pure cobalt exhibits two characteristic reversal mechanisms. For angles near in-plane field orientation, the magnetization reversal proceeds via instability of the uniform magnetic state, whereas in the vicinity of the out-of-plane (OP) orientation, magnetization inversion takes place by means of domain nucleation. Temperature dependent measurements enable the modification of the magnetocrystalline anisotropy and reveal a gradual disappearance of the domain nucleation process during magnetization reversal for elevated temperatures. Ultimately, this suppression of the domain nucleation process leads to the exclusive occurrence of uniform state instability reversal for all field orientations at sufficiently high temperature. Comparative magnetic measurements of C o90R u10 alloy samples allow the identification and confirmation of the high temperature remanent magnetization state of cobalt as an OP stripe domain state despite the reduction of magnetocrystalline anisotropy. Detailed micromagnetic simulations supplement the experimental results and corroborate the physical understanding of the temperature dependent behavior. Moreover, they enable a comprehensive identification of the complex energy balance in magnetic films with PMA, for which three different magnetic phases occur for sufficiently high anisotropy values, whose coexistence point is tricritical in nature.

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

    SciTech Connect

    Kuzhir, P. Magnet, C.; Fezai, H.; Meunier, A.; Bossis, G.; Rodríguez-Arco, L.; López-López, M. T.; Zubarev, A.

    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 σ{sub Y}∝Φ{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.

  2. MD Simulation of Particle Orientation in Magnetic Inks

    NASA Astrophysics Data System (ADS)

    Visscher; Günal

    1997-03-01

    We have done molecular-dynamics type simulations of particle re-orientation in a magnetic colloid, by a magnetic field during tape and disk manufacture. The model takes into account switching (in a Stoner- Wohlfarth model) as well as particle translation and rotation in response to magnetic, steric, Brownian, and hydrodynamic drag forces and torques. Magnetic interactions are fully included; hysteresis loops with and without magnetic interaction will be displayed, with corresponding Δ M curves. Images of the network structure at various points of the hysteresis loop will be shown. Further information is available at http:// www.mint.ua.edu/colloids/march.html.

  3. Studies of magnetism by nuclear orientation and NMRON

    NASA Astrophysics Data System (ADS)

    Turrell, B. G.

    1999-09-01

    Low temperature nuclear orientation (NO) and nuclear magnetic resonance on oriented nuclei (NMRON) are used to investigate the magnetic properties of solids, and are especially useful when high sensitivity is required, for example in the study of small or dilute systems. Measurement of the static hyperfine interaction and the nuclear spin-lattice and spin-spin relaxation times T 1 and T 2 yield information about the electronic magnetization and spin dynamics, respectively. A number of NMRON techniques are available and their application to the study of magnetism will be briefly discussed. In particular, the pulsed technique has been shown to be effective for studying insulators. Recent NO and NMRON measurements, primarily on insulating magnets and magnetic multilayers, will be reviewed. Spins of stable isotopes can also be investigated using NMR thermally detected by NO (NMR-TDNO), and this method, in combination with NMRON, has been recently applied in both metals and insulators to obtain information about nuclear spin-spin couplings, “frequency pulling” and nuclear magnons.

  4. 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.

  5. 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.

  6. Compassion is a constant.

    PubMed

    Scott, Tricia

    2015-11-01

    Compassion is a powerful word that describes an intense feeling of commiseration and a desire to help those struck by misfortune. Most people know intuitively how and when to offer compassion to relieve another person's suffering. In health care, compassion is a constant; it cannot be rationed because emergency nurses have limited time or resources to manage increasing demands.

  7. Compassion is a constant.

    PubMed

    Scott, Tricia

    2015-11-01

    Compassion is a powerful word that describes an intense feeling of commiseration and a desire to help those struck by misfortune. Most people know intuitively how and when to offer compassion to relieve another person's suffering. In health care, compassion is a constant; it cannot be rationed because emergency nurses have limited time or resources to manage increasing demands. PMID:26542898

  8. Are migrating raptors guided by a geomagnetic compass?

    USGS Publications Warehouse

    Thorup, Kasper; Fuller, Mark R.; Alerstam, T.; Hake, M.; Kjellen, N.; Standberg, R.

    2006-01-01

    We tested whether routes of raptors migrating over areas with homogeneous topography follow constant geomagnetic courses more or less closely than constant geographical courses. We analysed the routes taken over land of 45 individual raptors tracked by satellite-based radiotelemetry: 25 peregrine falcons, Falco peregrinus, on autumn migration between North and South America, and seven honey buzzards, Pernis apivorus, and 13 ospreys, Pandion haliaetus, on autumn migration between Europe and Africa. Overall, migration directions showed a better agreement with constant geographical than constant geomagnetic courses. Tracks deviated significantly from constant geomagnetic courses, but were not significantly different from geographical courses. After we removed movements directed far from the mean direction, which may not be migratory movements, migration directions still showed a better agreement with constant geographical than constant geomagnetic courses, but the directions of honey buzzards and ospreys were not significantly different from constant geomagnetic courses either. That migration routes of raptors followed by satellite telemetry are in closer accordance with constant geographical compass courses than with constant geomagnetic compass courses may indicate that geographical (e.g. based on celestial cues) rather than magnetic compass mechanisms are of dominating importance for the birds' long-distance orientation.

  9. Oscillating magnetic field disrupts magnetic orientation in Zebra finches, Taeniopygia guttata

    PubMed Central

    Keary, Nina; Ruploh, Tim; Voss, Joe; Thalau, Peter; Wiltschko, Roswitha; Wiltschko, Wolfgang; Bischof, Hans-Joachim

    2009-01-01

    Background Zebra finches can be trained to use the geomagnetic field as a directional cue for short distance orientation. The physical mechanisms underlying the primary processes of magnetoreception are, however, largely unknown. Two hypotheses of how birds perceive magnetic information are mainly discussed, one dealing with modulation of radical pair processes in retinal structures, the other assuming that iron deposits in the upper beak of the birds are involved. Oscillating magnetic fields in the MHz range disturb radical pair mechanisms but do not affect magnetic particles. Thus, application of such oscillating fields in behavioral experiments can be used as a diagnostic tool to decide between the two alternatives. Methods In a setup that eliminates all directional cues except the geomagnetic field zebra finches were trained to search for food in the magnetic north/south axis. The birds were then tested for orientation performance in two magnetic conditions. In condition 1 the horizontal component of the geomagnetic field was shifted by 90 degrees using a helmholtz coil. In condition 2 a high frequently oscillating field (1.156 MHz) was applied in addition to the shifted field. Another group of birds was trained to solve the orientation task, but with visual landmarks as directional cue. The birds were then tested for their orientation performance in the same magnetic conditions as applied for the first experiment. Results The zebra finches could be trained successfully to orient in the geomagnetic field for food search in the north/south axis. They were also well oriented in test condition 1, with the magnetic field shifted horizontally by 90 degrees. In contrast, when the oscillating field was added, the directional choices during food search were randomly distributed. Birds that were trained to visually guided orientation showed no difference of orientation performance in the two magnetic conditions. Conclusion The results indicate that zebra finches use a

  10. The Radical Pair Mechanism and the Avian Chemical Compass: Quantum Coherence and Entanglement

    SciTech Connect

    Zhang, Yiteng; Kais, Sabre; Berman, Gennady Petrovich

    2015-02-02

    We review the spin radical pair mechanism which is a promising explanation of avian navigation. This mechanism is based on the dependence of product yields on 1) the hyperfine interaction involving electron spins and neighboring nuclear spins and 2) the intensity and orientation of the geomagnetic field. One surprising result is that even at ambient conditions quantum entanglement of electron spins can play an important role in avian magnetoreception. This review describes the general scheme of chemical reactions involving radical pairs generated from singlet and triplet precursors; the spin dynamics of the radical pairs; and the magnetic field dependence of product yields caused by the radical pair mechanism. The main part of the review includes a description of the chemical compass in birds. We review: the general properties of the avian compass; the basic scheme of the radical pair mechanism; the reaction kinetics in cryptochrome; quantum coherence and entanglement in the avian compass; and the effects of noise. We believe that the quantum avian compass can play an important role in avian navigation and can also provide the foundation for a new generation of sensitive and selective magnetic-sensing nano-devices.

  11. 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

  12. 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...

  13. Magnetic and elastic properties of CoFe2O4- polydimethylsiloxane magnetically oriented elastomer nanocomposites

    NASA Astrophysics Data System (ADS)

    Soledad Antonel, P.; Jorge, Guillermo; Perez, Oscar E.; Butera, Alejandro; Gabriela Leyva, A.; Martín Negri, R.

    2011-08-01

    Magnetic elastic structured composites were prepared by using CoFe2O4 ferromagnetic and superparamagnetic nanoparticles as fillers in polydimethylsiloxane (PDMS) matrixes, which were cured in the presence of a uniform magnetic field. Cobalt-iron oxide nanoparticles of three different average sizes (between 2 and 12 nm) were synthesized and characterized. The smallest nanoparticles presented superparamagnetic behavior, with a blocking temperature of approximately 75 K, while larger particles are already blocked at room temperature. Macroscopically structured-anisotropic PDMS-CoFe2O4 composites were obtained when curing the dispersion of the nanoparticles in the presence of a uniform magnetic field (0.3 T). The formation of the particle's chains (needles) orientated in the direction of the magnetic field was observed only when loading with the larger magnetically blocked nanoparticles. The SEM images show that the needles are formed by groups of nanoparticles which retain their original average size. The Young's moduli of the structured composites are four times larger when measured along the oriented needles than in the perpendicular direction. Magnetization (VSM) and ferromagnetic resonance curves of the structured composites were determined as a function of the relative orientation between the needles and the probe field. The remanence magnetization was 30% higher when measured parallel to the needles, while the coercive field remains isotropic. These observations are discussed in terms of the individual nanoparticle's properties and its aggregation in the composites.

  14. Determining the axis orientation of cylindrical magnetic flux rope

    NASA Astrophysics Data System (ADS)

    Rong, Zhaojin; Wan, Weixing; Shen, Chao; Zhang, Tielong; Lui, Anthony; Wang, Yuming; Dunlop, malcolm; Zhang, Yongcun; Zong, Qiugang

    2013-04-01

    We develop a new simple method for inferring the orientation of a magnetic flux rope, which is assumed to be a time-independent cylindrically symmetric structure via the direct single-point analysis of magnetic field structure. The model tests demonstrate that, for the cylindrical flux rope regardless of whether it is force-free or not, the method can consistently yield the axis orientation of the flux rope with higher accuracy and stability than the minimum variance analysis of the magnetic field and the Grad-Shafranov reconstruction technique. Moreover, the radial distance to the axis center and the current density can also be estimated consistently. Application to two actual flux transfer events observed by the four satellites of the Cluster mission demonstrates that the method is more appropriate to be used for the inner part of flux rope, which might be closer to the cylindrical structure, showing good agreement with the results obtained from the optimal Grad-Shafranov reconstruction and the least squares technique of Faraday's law, but fails to produce such agreement for the outer satellite that grazes the flux rope. Therefore, the method must be used with caution.

  15. Anisotropic thermal property of magnetically oriented carbon nanotube polymer composites

    NASA Astrophysics Data System (ADS)

    Li, Bin; Dong, Shuai; Wang, Caiping; Wang, Xiaojie; Fang, Jun

    2016-04-01

    This paper proposes a method for preparing multi-walled carbon nanotubea/polydimethylsiloxane (MWCNTs/PDMS) composites with enhanced thermal properties by using a high magnetic field (up to 10T). The MWCNT are oriented magnetically inside a silicone by in-situ polymerization method. The anisotropic structure would be expected to produce directional thermal conductivity. This study will provide a new approach to the development of anisotropic thermal-conductive polymer composites. Systematic studies with the preparation of silicone/graphene composites corresponding to their thermal and mechanical properties are carried out under various conditions: intensity of magnetic field, time, temperature, fillings. The effect of MWCNT/graphene content and preparation procedures on thermal conductivity of composites is investigated. Dynamic mechanical analysis (DMA) is used to reveal the mechanical properties of the composites in terms of the filling contents and magnetic field strength. The scanning electron microscope (SEM) is used to observe the micro-structure of the MWCNT composites. The alignment of MWCNTs in PDMS matrix is also studied by Raman spectroscopy. The thermal conductivity measurements show that the magnetically aligned CNT-composites feature high anisotropy in thermal conductivity.

  16. 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.

  17. Ecological causes and consequences of bird orientation.

    PubMed

    Alerstam, T

    1991-01-01

    An advanced orientation capability offers possibilities for birds to optimize movement patterns in a wide variety of ecological situations. The adaptive significance of various patterns of angular dispersion and of orientation responses to topography and sociality are elucidated. The orientation capacity is characterized by flexibility, exemplified by reorientation, promoting safety and restoration of fat reserves during migration. There are also limitations to the orientation process, leading to costs of migration through mis- or disorientation, and to constraints on the evolution of routes and timing of migratory flights. Young migrants may acquire an erroneous compass sense, and misorient several thousands of kilometers off their normal course. Widespread and dense fog of long duration causes disorientation and mortality among land birds migrating over the sea. Orientational constraints in the evolution of migration routes may be most easily disclosed at high geographic and magnetic latitudes. Here the birds are faced with special difficulties in using their celestial as well as their magnetic compasses. The sun compass could be used for great circle orientation, but observed spring flight trajectories of high-arctic waders and geese seem to conform with rhumbline routes. PMID:1838516

  18. Compassion: a universal language.

    PubMed

    Booth, Leigh

    2016-01-01

    Nursing was founded on the ideas of care and compassion. Research has shown that nursing students have the potential to struggle with the concept of compassion or rather maintain this compassion throughout their careers. The compassion and excitement that many students begin nursing programs with can quickly be dissolved with the high demands of nursing curriculum. With teaching strategies afforded through service learning activities such as international medical trips, compassion can be reignited and demonstrated in ways that are more evident since this is not a typical clinical setting. It is vital that nursing education utilize any available resources in order to demonstrate and model compassionate behaviors in order for students to not lose sight of what compassion means for the profession and calling of nursing. PMID:27536804

  19. Influence of magnetic field on the orientation of anisotropic magnetic particles at liquid interfaces.

    PubMed

    Newton, Bethany J; Brakke, Kenneth A; Buzza, D Martin A

    2014-12-21

    We study theoretically the influence of an external magnetic field on the orientation of an ellipsoidal magnetic particle adsorbed at a liquid interface. Using the finite element program Surface Evolver, we calculate the equilibrium meniscus shape around the ellipsoidal particle and its equilibrium tilt angle with respect to the undeformed interface θt when a magnetic field B is applied perpendicular to the interface. We find that as we increase field strength, θt increases and at a critical magnetic field Bc1 and tilt angle θc1, the particle undergoes a discontinuous transition to the 'perpendicular' orientation (θt = 90°). Our results agree qualitatively with the simplified theory of Bresme and Faraudo [F. Bresme and J. Faraudo, J. Phys.: Condens. Matter, 2007, 19, 375110] which assumes that the liquid interface is flat, while they agree quantitatively with recent lattice-Boltzmann simulations of Davies et al. [G. Davies et al., Soft Matter, 2014, 10, 6742] which account for the deformation of the liquid meniscus. We also show for the first time that upon reducing the external magnetic field, at a critical magnetic field Bc2 < Bc1, the particle undergoes a second discontinuous transition from the perpendicular orientation to a finite tilt angle θc2 < θc1. In other words, for micron-sized particles where the thermal energy kBT is negligible compared to the interfacial energy, the tilt angle vs. magnetic field curve exhibits hysteresis behaviour. Due to the higher degree of accuracy of the Surface Evolver method, we are able to analyse the behaviour of the particles near these orientational transitions accurately and study how the critical quantities Bc1, Bc2, θc1 and θc2 vary with particle aspect ratio and contact angle.

  20. Magnetic preferential orientation of metal oxide superconducting materials

    DOEpatents

    Capone, D.W.; Dunlap, B.D.; Veal, B.W.

    1990-07-17

    A superconductor comprised of a polycrystalline metal oxide such as YBa[sub 2]Cu[sub 3]O[sub 7[minus]X] (where 0 < X < 0.5) exhibits superconducting properties and is capable of conducting very large current densities. By aligning the two-dimensional Cu-O layers which carry the current in the superconducting state in the a- and b-directions, i.e., within the basal plane, a high degree of crystalline axes alignment is provided between adjacent grains permitting the conduction of high current densities. The highly anisotropic diamagnetic susceptibility of the polycrystalline metal oxide material permits the use of an applied magnetic 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. 4 figs.

  1. Magnetic preferential orientation of metal oxide superconducting materials

    DOEpatents

    Capone, Donald W.; Dunlap, Bobby D.; Veal, Boyd W.

    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. Beyond compassion fatigue: the transactional model of physician compassion.

    PubMed

    Fernando, Antonio T; Consedine, Nathan S

    2014-08-01

    Physician compassion is expected by both patients and the medical profession and is central to effective clinical practice. Yet, despite the centrality of compassion to medical practice, most compassion-related research has focused on compassion fatigue, a specific type of burnout among health providers. Although such research has highlighted the phenomenon among clinicians, the focus on compassion fatigue has neglected the study of compassion itself. In this article, we present the Transactional Model of Physician Compassion. After briefly critiquing the utility of the compassion fatigue concept, we offer a view in which physician compassion stems from the dynamic but interrelated influences of physician, patient and family, clinical situation, and environmental factors. Illuminating the specific aspects of physicians' intrapersonal, interpersonal, clinical, and professional functioning that may interfere with or enhance compassion allows for targeted interventions to promote compassion in both education and practice as well as to reduce the barriers that impede it.

  3. Effect of Object Orientation Angle on T2* Image and Reconstructed Magnetic Susceptibility: Numerical Simulations

    PubMed Central

    Chen, Zikuan; Calhoun, Vince

    2013-01-01

    The magnetic field resulting from material magnetization in magnetic resonance imaging (MRI) has an object orientation effect, which produces an orientation dependence for acquired T2* images. On one hand, the orientation effect can be exploited for object anisotropy investigation (via multi-angle imaging); on the other hand, it is desirable to remove the orientation dependence using magnetic susceptibility reconstruction. In this report, we design a stick-star digital phantom to simulate multiple orientations of a stick-like object and use it to conduct various numerical simulations. Our simulations show that the object orientation effect is not propagated to the reconstructed magnetic susceptibility distribution. This suggests that accurate susceptibility reconstruction methods should be largely orientation independent. PMID:25114542

  4. 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.

  5. 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

  6. Perceptual Strategies of Pigeons to Detect a Rotational Centre—A Hint for Star Compass Learning?

    PubMed Central

    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

  7. 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…

  8. Studies of magnetism using nuclear orientation and related NMR techniques

    NASA Astrophysics Data System (ADS)

    Pond, James F.

    2001-09-01

    Nuclear Orientation and related NMR techniques have been used to study three magnetic insulators: Mn(COOCH3)2·4H2O, MnCl2·4H2O and CoCl2·6H 2O. Continuous wave NMR thermally detected by Nuclear Orientation has been used to investigate the magnetic properties and spin dynamics of the quasi-2-dimensional ferromagnet 54Mn-Mn(COOCH3)2·4H 2O. The system exhibits a frequency pulling effect due to the indirect Suhl-Nakamura interaction between nuclear spins and the electronic spin excitation spectrum is related to the coupling strength of the nuclear spins. The temperature dependence of the frequency pulling effect was measured for the two crystalline sublattices Mn1 and Mn2 in low magnetic field. The spectra show a structure not predicted theoretically. The current theory is valid only for I = 1/2 with uniaxial crystalline anisotropy fields. The theory of frequency pulling has been extended here to the case of I ≥ 1/2 and non-uniaxial crystalline anisotropy fields and the resonant frequencies and linewidths have been calculated as a function of temperature. The new theory and data agree well in terms of the magnitude and temperature dependence of the frequency pulling. Discrepancies are likely due to simplifying assumptions when calculating the electronic magnon spectrum. Classical and quantum numerical simulations confirm qualitatively the predictions of the model. The first Low Temperature Nuclear Orientation experiments on isotopes implanted into insulators is reported. Radioactive 56Mn ions have been implanted into insulating, antiferromagnetic crystals of MnCl 2·4H2O and CoCl2·6H2O. In MnCl2·4H2O, comparison of the gamma-ray anisotropy of the 56Mn nuclei with that of 54Mn, doped into the sample during growth, showed that both the 56Mn and 54Mn spins felt a very similar hyperfine field. The site occupancy factor in a simple, two site model was deduced to be 0.96+0.04-0.07 . In CoCl2·6H2O, the average hyperfine field for the implanted 56Mn was significantly

  9. Stellar compass for the Clementine Mission

    SciTech Connect

    Wilson, B.

    1994-11-15

    A CCD sensor with 42 x 28 degrees FOV and 576 x 384 pixels was built by the Advanced Technology Program (ATP) in the Physics Department at LLNL. That sensor, called the StarTracker camera, is used on the Clementine Lunar Mapping mission between January and May, 1994. Together with the Stellar Compass software, the StarTracker camera provided a way of identifying its orientation to within about 150 microradians in camera body pitch and yaw. This presentation will be an overview of basically how the Stellar Compass software works, along with showing some of its performance results.

  10. 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

  11. 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

  12. Filamentary structure and magnetic field orientation in Musca

    NASA Astrophysics Data System (ADS)

    Cox, N. L. J.; Arzoumanian, D.; André, Ph.; Rygl, K. L. J.; Prusti, T.; Men'shchikov, A.; Royer, P.; Kóspál, Á.; Palmeirim, P.; Ribas, A.; Könyves, V.; Bernard, J.-Ph.; Schneider, N.; Bontemps, S.; Merin, B.; Vavrek, R.; Alves de Oliveira, C.; Didelon, P.; Pilbratt, G. L.; Waelkens, C.

    2016-05-01

    Herschel has shown that filamentary structures are ubiquitous in star-forming regions, in particular in nearby molecular clouds associated with Gould's Belt. High dynamic range far-infrared imaging of the Musca cloud with SPIRE and PACS reveals at least two types of filamentary structures: (1) the main ~10-pc scale high column-density linear filament; and (2) low column-density striations in close proximity to the main filament. In addition, we find features with intermediate column densities (hair-like strands) that appear physically connected to the main filament. We present an analysis of this filamentary network traced by Herschel and explore its connection with the local magnetic field. We find that both the faint dust emission striations and the plane-of-the-sky (POS) magnetic field are locally oriented close to perpendicular to the high-density main filament (position angle ~25-35°). The low-density striations and strands are oriented parallel to the POS magnetic field lines, which are derived previously from optical polarization measurements of background stars and more recently from Planck observations of dust polarized emission. The position angles are 97 ± 25°, 105 ± 7°, and 105 ± 5°. From these observations, we propose a scenario in which local interstellar material in this cloud has condensed into a gravitationally-unstable filament (with "supercritical" mass per unit length) that is accreting background matter along field lines through the striations. We also compare the filamentary structure in Musca with what is seen in similar Herschel observations of the Taurus B211/3 filament system and find that there is significantly less substructure in the Musca main filament than in the B211/3 filament. We suggest that the Musca cloud may represent an earlier evolutionary stage in which the main filament has not yet accreted sufficient mass and energy to develop a multiple system of intertwined filamentary components. Herschel is an ESA space

  13. The manipulation of magnetic coercive field and orientation of magnetic anisotropy via electric fields

    NASA Astrophysics Data System (ADS)

    Xiang, Jun-Sen; Ye, Jun; Yang, Yun-Long; Xie, Yong; Li, Wei; Chen, Zi-Yu

    2016-08-01

    We report the effects of the electric field on the magnetic coercive field (H c) and uniaxial magnetic anisotropy (UMA) orientation of polycrystalline Ni film grown on an unpoled (0 1 1) [Pb(Mg1/3Nb2/3)O3](1-x)-[PbTiO3] x (PMN-PT) single crystal substrate. Under various electric fields, normalized magnetic hysteresis loops of Ni films change in width; this represents the change of coercive field (ΔH c). Loop shapes are found to depend on the angle between the magnetic field and the sample, where changes in the shape reveal a small rotation of UMA. All these changes show that the magnetic properties vary periodically with a periodic electric field, by strain-mediated magnetoelectric coupling in the Ni/Ag/PMN-PT/Ag heterostructure. The poled PMN-PT produces strains under electric fields in the range of  -4.2 kV cm-1  ⩽  E  ⩽  4.2 kV cm-1, then transfers it to Ni films resulting in changes to its H c and UMA. The curves of the in-plane H c and strain, at two mutually orthogonal directions, represent butterfly patterns versus the applied electric field. In addition, the changes observed in both the H c and strain show asymmetric features in two orthogonal directions, which results in a small rotation angle of the UMA of Ni as the electric field decreases. The effective manipulation of magnitude and orientation of magnetic anisotropy via electric fields in ferromagnetic/ferroelectric (FM/FE) heterostructures is an important step towards controlling the magnetic tunnel junctions.

  14. The manipulation of magnetic coercive field and orientation of magnetic anisotropy via electric fields

    NASA Astrophysics Data System (ADS)

    Xiang, Jun-Sen; Ye, Jun; Yang, Yun-Long; Xie, Yong; Li, Wei; Chen, Zi-Yu

    2016-08-01

    We report the effects of the electric field on the magnetic coercive field (H c) and uniaxial magnetic anisotropy (UMA) orientation of polycrystalline Ni film grown on an unpoled (0 1 1) [Pb(Mg1/3Nb2/3)O3](1‑x)–[PbTiO3] x (PMN-PT) single crystal substrate. Under various electric fields, normalized magnetic hysteresis loops of Ni films change in width; this represents the change of coercive field (ΔH c). Loop shapes are found to depend on the angle between the magnetic field and the sample, where changes in the shape reveal a small rotation of UMA. All these changes show that the magnetic properties vary periodically with a periodic electric field, by strain-mediated magnetoelectric coupling in the Ni/Ag/PMN-PT/Ag heterostructure. The poled PMN-PT produces strains under electric fields in the range of  ‑4.2 kV cm‑1  ⩽  E  ⩽  4.2 kV cm‑1, then transfers it to Ni films resulting in changes to its H c and UMA. The curves of the in-plane H c and strain, at two mutually orthogonal directions, represent butterfly patterns versus the applied electric field. In addition, the changes observed in both the H c and strain show asymmetric features in two orthogonal directions, which results in a small rotation angle of the UMA of Ni as the electric field decreases. The effective manipulation of magnitude and orientation of magnetic anisotropy via electric fields in ferromagnetic/ferroelectric (FM/FE) heterostructures is an important step towards controlling the magnetic tunnel junctions.

  15. Influence of spherical assembly of copper ferrite nanoparticles on magnetic properties: orientation of magnetic easy axis.

    PubMed

    Chatterjee, Biplab K; Bhattacharjee, Kaustav; Dey, Abhishek; Ghosh, Chandan K; Chattopadhyay, Kalyan K

    2014-06-01

    The magnetic properties of copper ferrite (CuFe2O4) nanoparticles prepared via sol-gel auto combustion and facile solvothermal method are studied focusing on the effect of nanoparticle arrangement. Randomly oriented CuFe2O4 nanoparticles (NP) are obtained from the sol-gel auto combustion method, while the solvothermal method allows us to prepare iso-oriented uniform spherical ensembles of CuFe2O4 nanoparticles (NS). X-ray diffractometry (XRD), atomic absorption spectroscopy (AAS), infra-red (IR) spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), (57)Fe Mössbauer spectroscopy and vibrating sample magnetometer (VSM) are used to investigate the composition, microstructure and magnetic properties of as-prepared ferrite nanoparticles. The field-dependent magnetization measurement for the NS sample at low temperature exhibits a step-like rectangular hysteresis loop (M(R)/M(S) ~ 1), suggesting cubic anisotropy in the system, whereas for the NP sample, typical features of uniaxial anisotropy (M(R)/M(S) ~ 0.5) are observed. The coercive field (HC) for the NS sample shows anomalous temperature dependence, which is correlated with the variation of effective anisotropy (K(E)) of the system. A high-temperature enhancement of H(C) and K(E) for the NS sample coincides with a strong spin-orbit coupling in the sample as evidenced by significant modification of Cu/Fe-O bond distances. The spherical arrangement of nanocrystals at mesoscopic scale provokes a high degree of alignment of the magnetic easy axis along the applied field leading to a step-like rectangular hysteresis loop. A detailed study on the temperature dependence of magnetic anisotropy of the system is carried out, emphasizing the influence of the formation of spherical iso-oriented assemblies. PMID:24714977

  16. The Newly Upgraded Large COMPASS Polarized Target

    SciTech Connect

    Gautheron, F.

    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.

  17. COMPASS-II: COMPASS Future Programs

    SciTech Connect

    Doshita, Norihiro; 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.

  18. Orientation of paramecium swimming in a static magnetic field: Dependence on membrane lipid fluidity.

    PubMed

    Nakaoka, Yasuo; Itoh, Junya; Shimizu, Kikuo

    2011-01-01

    We studied the swimming orientation of the ciliated protozoan Paramecium aurelia in a static magnetic field (0.78 T). P. aurelia is a complex of species termed syngens, whose cell morphology appears similar on microscopic examination. In the magnetic field, the cells of some syngens gradually changed their swimming orientation so that they were swimming perpendicular or parallel to the magnetic field, although such sensitivity to magnetic fields differs between syngens. When the temperature of the cell suspension was raised, the magnetic sensitivity of the cells was decreased. On the other hand, when the cells were cultured beforehand at a high temperature, their magnetic sensitivity was increased. These results raise the possibility that membrane lipid fluidity, which is inversely proportional to the membrane lipid order, contributes to the magnetic orientation of syngens. In this study, measurements of membrane lipid fluidity obtained using fluorescence image analysis with the lipophilic dye, laurdan (6-lauroyl-2-dimethylaminonaphtalene), showed that the degree of membrane lipid fluidity was correlated with the differences in magnetic orientation between syngens. That is, the syngens with decreased membrane fluidity showed an increased degree of magnetic orientation. Therefore, the membrane lipid order is a key factor in the magnetic orientation of Paramecium swimming.

  19. Self-compassion and life satisfaction in gay men.

    PubMed

    Jennings, Lisa K; Philip Tan, P

    2014-12-01

    Studies have shown that gay men are at increased risk for anxiety and depression due to social oppression; research suggests that self-compassion is positively associated with life-satisfaction and emotional resilience. In a sample of 68 gay men (M age = 39.7 yr., SD = 16.3), the influence of self-compassion on satisfaction with life was examined while controlling for age, income, and openness about sexual orientation. Analysis of the data revealed that self-compassion was a significant predictor of satisfaction with life. Implications of this finding were discussed.

  20. Object-Oriented Fast Multipole Simulation: Magnetic Colloids

    NASA Astrophysics Data System (ADS)

    Visscher, Pieter; Günal, Yüksel

    1997-08-01

    In simulating a system of N particles, if the interaction is long-ranged all pair interactions must be calculated, requiring CPU time of order N^2. Recently-developed ``fast multipole'' methods (FMM) can reduce this time to order N, at the cost of considerable programming complexity. We have developed an object-oriented approach which uses similar ideas but is conceptually much simpler. The system is represented by a hierarchical tree whose root is the entire system and whose lowest nodes are the particles. The entire calculation of the particle interactions consists of a single call to a recursive function CalculateInteractions(A,B) with A=B=root, which uses a simple opening-angle criterion to choose between multipole expansion and calling itself (subdividing A and B.) The resulting algorithm is essentially equivalent to the FMM, but the choice of when to subdivide (which is laboriously hard-wired in FMM) is made automatically. We will discuss the implementation of periodic BCs and the application of the method to continuum systems (cylindrical magnetic particles).

  1. Magnetic Orientation in Biology:. Virus Structure - Blood Clot Assembly - Cell Guidance

    NASA Astrophysics Data System (ADS)

    Torbet, J.

    2005-07-01

    Our childhood games with permanent magnets leave us with the impression that matter, in general, does not respond to a magnetic field. In reality, virtually everything is subjected to minute forces of attraction, repulsion or orientation. Strong fields combined with better understanding allow us to exploit these effects to tackle biological problems. In particular, the very weak diamagnetic anisotropy associated with individual molecules can give rise to high orientation of well organized structures such as crystals, liquid-crystals, semi-rigid polymers and individual cells. High orientation is often accompanied by better data and superior properties. In some circumstances, such as in crystallization, the orientating torque might induce effects over and above simple orientation. Magnetic field orientation has a number of advantages over other orienting techniques. Drawing or spinning produce fibers and can alter structure or cause damage while template methods invariable work only over a short range. The application of an electric field can cause heating and electrophoresis. In contrast, a magnetic field acts at a distance allowing uniform orientation in bulk and the creation of composites with components having different orientations. The contribution that magnetic orientation has made to a range of biological topics is illustrated by briefly describing a number of examples. For example, it has been a boon to x-ray studies of some non-crystalline filamentous complexes (e.g. fibrin, actin, microtubules, bacterial flagella and filamentous viruses) and is being vigorously exploited in NMR. The blood-clot polymer, fibrin, forms highly oriented gels when polymerized in a strong field and a number of its properties have been elucidated as a result. Magnetically oriented scaffolds of collagen, the major connective tissue protein, and fibrin are being used to study cell contact guidance. Oriented biomaterials might eventually be incorporated into specialized wound

  2. Trials of an acoustic transponding fish tag compass.

    PubMed

    Mitson, R B; Storeton-West, T J; Pearson, N D

    1982-01-01

    The instantaneous orientation of a fish can be determined by attaching a magnetic compass sensor to it and then by acoustically telemetering the information to a research vessel's electronic sector scanning sonar. The sensor is housed in a cylindrical capsule with an acoustic transponder to which it is electronically interconnected. Its size and weight are such that it can be fitted to fish of about 40 cm length and above. An operational life of 52 h is obtained from the tag when it is interrogated by the sonar at a consistent rate of 2 pulses s-1. If the rate is reduced by half, the life can be extended to about 68-70 h. Directional accuracy is limited to +/- 22.5 degrees by the physical size of components used in the sensor. Trials of the prototype are described.

  3. 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.

  4. Monolithic integration of focused 2D GMR spin valve magnetic field sensor for high-sensitivity (compass) applications (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Ueberschär, Olaf; Almeida, Maria J.; Matthes, Patrick; Müller, Mathias; Ecke, Ramona; Exner, Horst; Schulz, Stefan E.

    2015-09-01

    We have designed and fabricated 2D GMR spin valve sensors on the basis of IrMn/CoFe/Cu/CoFe/NiFe nanolayers in monolithic integration for high sensitivity applications. For a maximum signal-to-noise ratio, we realize a focused double full bridge layout featuring an antiparallel exchange bias pinning for neighbouring meanders and an orthogonal pinning for different bridges. This precise alignment is achieved with microscopic precision by laser heating and subsequent in-field cooling. Striving for maximum signal sensitivity and minimum hysteresis, we study in detail the impact of single meander geometry on the total magnetic structure and electronic transport properties. The investigated geometrical parameters include stripe width, stripe length, cross bar material and total meander length. In addition, the influence of the relative alignment between reference magnetization (pinned layer) and shape anisotropy (free layer) is studied. The experimentally obtained data are moreover compared to the predictions of tailored micromagnetic simulations. Using a set of optimum parameters, we demonstrate that our sensor may readily be employed to measure small magnetic fields, such as the ambient (geomagnetic) field, in terms of a 2D vector with high spatial (~200 μm) and temporal (~1 ms) resolution.

  5. Magnetic properties and magnetic domain structure of grain-oriented Fe-3%Si steel under compression

    NASA Astrophysics Data System (ADS)

    Perevertov, O.; Schäfer, R.

    2016-09-01

    The influence of an applied compressive stress on the magnetic properties and domain structure in Goss-textured (110) [001] Fe-3%Si steel is studied. The magnetic domains and magnetization processes were observed by longitudinal Kerr microscopy at different levels of compressive stress. With stress increase the domain structure without applied field evolves from 180° slab-like domains along the surface-parallel easy axis first into stress pattern I, then into the checkerboard pattern and finally into stress pattern II, in which all internal domains are oriented along the transverse axes. The magnetization process under compression is realized by surface closure [001] domains that grow into the bulk at the expense of transverse domains. The domain evolution by these three stress patterns is not practically noticeable in hysteresis curves above 10 MPa—they change continuously with the same effective field being valid for curves from 10 to 67 MPa. The comparison with previous measurements under different stress/cutting angle combinations shows that for the prediction of a constricted hysteresis loop it is sufficient to consider the energy difference between surface-parallel and transverse easy axes neglecting details of the spatial organization of transverse domains.

  6. Differential effects of magnetic pulses on the orientation of naturally migrating birds.

    PubMed

    Holland, Richard A

    2010-11-01

    In migratory passerine birds, strong magnetic pulses are thought to be diagnostic of the remagnetization of iron minerals in a putative sensory system contained in the beak. Previous evidence suggests that while such a magnetic pulse affects the orientation of migratory birds in orientation cages, no effect was present when pulse-treated birds were tested in natural migration. Here we show that two migrating passerine birds treated with a strong magnetic pulse, designed to alter the magnetic sense, migrated in a direction that differed significantly from that of controls when tested in natural conditions. The orientation of treated birds was different depending on the alignment of the pulse with respect to the magnetic field. These results can aid in advancing understanding of how the putative iron-mineral-based receptors found in birds' beaks may be used to detect and signal the intensity and/or direction of the Earth's magnetic field.

  7. Differential effects of magnetic pulses on the orientation of naturally migrating birds

    PubMed Central

    Holland, Richard A.

    2010-01-01

    In migratory passerine birds, strong magnetic pulses are thought to be diagnostic of the remagnetization of iron minerals in a putative sensory system contained in the beak. Previous evidence suggests that while such a magnetic pulse affects the orientation of migratory birds in orientation cages, no effect was present when pulse-treated birds were tested in natural migration. Here we show that two migrating passerine birds treated with a strong magnetic pulse, designed to alter the magnetic sense, migrated in a direction that differed significantly from that of controls when tested in natural conditions. The orientation of treated birds was different depending on the alignment of the pulse with respect to the magnetic field. These results can aid in advancing understanding of how the putative iron-mineral-based receptors found in birds' beaks may be used to detect and signal the intensity and/or direction of the Earth's magnetic field. PMID:20453067

  8. Small angle x-ray scattering studies of magnetically oriented lipid bilayers.

    PubMed Central

    Hare, B J; Prestegard, J H; Engelman, D M

    1995-01-01

    Magnetically oriented lipid/detergent bilayers are potentially useful for studies of membrane-associated molecules and complexes using x-ray scattering and nuclear magnetic resonance (NMR). To establish whether the system is a reasonable model of a phospholipid bilayer, we have studied the system using x-ray solution scattering to determine the bilayer thickness, interparticle spacing, and orientational parameters for magnetically oriented lipid bilayers. The magnetically orientable samples contain the phospholipid L-alpha-dilauroylphosphatidylcholine (DLPC) and the bile salt analog 3-[(3-cholamidopropyl)dimethylammonio]-2-hydroxy-1-propanesulfonate (CHAPSO) in a 3:1 molar ratio in 70% water (w/v) and are similar to magnetically orientable samples used as NMR media for structural studies of membrane-associated molecules. A bilayer thickness of 30 A was determined for the DLPC/CHAPSO particles, which is the same as the bilayer thickness of pure DLPC vesicles, suggesting that the CHAPSO is not greatly perturbing the lipid bilayer. These data, as well as NMR data on molecules incorporated in the oriented lipid particles, are consistent with the sample consisting of reasonably homogeneous and well dispersed lipid particles. Finally, the orientational energy of the sample suggests that the size of the cooperatively orienting unit in the samples is 2 x 10(7) phospholipid molecules. Images FIGURE 1 PMID:8580332

  9. Orientation by solidification in a magnetic field: A new process to texture SmCo compounds used as permanent magnets

    NASA Astrophysics Data System (ADS)

    Legrand, B. A.; Chateigner, D.; Perrier de la Bathie, R.; Tournier, R.

    1997-02-01

    The solidification of molten alloys in a static magnetic field is proposed as a new way of orienting polycrystalline materials. A high degree of orientation is obtained with samarium-cobalt compounds solidified in a static magnetic field. Whatever the cooling condition used from the liquid state, a magnetic field of several tesla induces crystallographic orientation in the solid. The easy magnetization axis of the polycrystal lies along the direction of the field applied during solidification. This texturing process is applied to the elaboration of Sm 2Co 17 permanent magnets. Anisotropic bulk magnets with a coercive field up to 2250 kA/m and energy product above 160 kJ/m 3 are obtained. This process provides an alternative to the currently used industrial technology which is based on powder metallurgy. The paramagnetic susceptibility of the substituted Sm 2Co 17 compounds is measured at high temperatures from which the susceptibility anisotropy at solidification temperature is determined. The orientation of the sample, solidified in a cold induction crucible, is analysed as a function of the applied magnetic field. Assuming a model in which particles are free to orient before complete solidification takes place, a critical size of these particles is deduced.

  10. Useful oriented immobilization of antibodies on chimeric magnetic particles: direct correlation of biomacromolecule orientation with biological activity by AFM studies.

    PubMed

    Marciello, Marzia; Filice, Marco; Olea, David; Velez, Marisela; Guisan, José M; Mateo, Cesar

    2014-12-16

    The preparation and performance of a suitable chimeric biosensor based on antibodies (Abs) immobilized on lipase-coated magnetic particles by means of a standing orienting strategy are presented. This novel system is based on hydrophobic magnetic particles coated with modified lipase molecules able to orient and further immobilize different Abs in a covalent way without any previous site-selective chemical modification of biomacromolecules. Different key parameters attending the process were studied and optimized. The optimal preparation was performed using a controlled loading (1 nmol Ab g(-1) chimeric support) at pH 9 and a short reaction time to recover a biological activity of about 80%. AFM microscopy was used to study and confirm the Abs-oriented immobilization on lipase-coated magnetic particles and the final achievement of a highly active and recyclable chimeric immune sensor. This direct technique was demonstrated to be a powerful alternative to the indirect immunoactivity assay methods for the study of biomacromolecule-oriented immobilizations.

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

    SciTech Connect

    Smith, M.E.; Benicewicz, B.C.; Douglas, D.P.; Earls, J.D.; Priester, R.D. Jr.

    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.

  12. Two different types of light-dependent responses to magnetic fields in birds.

    PubMed

    Wiltschko, Roswitha; Ritz, Thorsten; Stapput, Katrin; Thalau, Peter; Wiltschko, Wolfgang

    2005-08-23

    A model of magnetoreception proposes that the avian magnetic compass is based on a radical pair mechanism, with photon absorption leading to the formation of radical pairs. Analyzing the predicted light dependency by testing migratory birds under monochromatic lights, we found that the responses of birds change with increasing intensity. The analysis of the orientation of European robins under 502 nm turquoise light revealed two types of responses depending on light intensity: under a quantal flux of 8.10(15) quanta m(-2) s(-1), the birds showed normal migratory orientation in spring as well as in autumn, relying on their inclination compass. Under brighter light of 54.10(15) quanta m(-2) s(-1), however, they showed a "fixed" tendency toward north that did not undergo the seasonal change and proved to be based on magnetic polarity, not involving the inclination compass. When birds were exposed to a weak oscillating field, which specifically interferes with radical pair processes, the inclination compass response was disrupted, whereas the response to magnetic polarity remained unaffected. These findings indicate that the normal inclination compass used for migratory orientation is based on a radical-pair mechanism, whereas the fixed direction represents a novel type of light-dependent orientation based on a mechanism of a different nature.

  13. 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.

  14. 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.

  15. Noncontact orientation of objects in three-dimensional space using magnetic levitation.

    PubMed

    Subramaniam, Anand Bala; Yang, Dian; Yu, Hai-Dong; Nemiroski, Alex; Tricard, Simon; Ellerbee, Audrey K; Soh, Siowling; Whitesides, George M

    2014-09-01

    This paper describes several noncontact methods of orienting objects in 3D space using Magnetic Levitation (MagLev). The methods use two permanent magnets arranged coaxially with like poles facing and a container containing a paramagnetic liquid in which the objects are suspended. Absent external forcing, objects levitating in the device adopt predictable static orientations; the orientation depends on the shape and distribution of mass within the objects. The orientation of objects of uniform density in the MagLev device shows a sharp geometry-dependent transition: an analytical theory rationalizes this transition and predicts the orientation of objects in the MagLev device. Manipulation of the orientation of the levitating objects in space is achieved in two ways: (i) by rotating and/or translating the MagLev device while the objects are suspended in the paramagnetic solution between the magnets; (ii) by moving a small external magnet close to the levitating objects while keeping the device stationary. Unlike mechanical agitation or robotic selection, orienting using MagLev is possible for objects having a range of different physical characteristics (e.g., different shapes, sizes, and mechanical properties from hard polymers to gels and fluids). MagLev thus has the potential to be useful for sorting and positioning components in 3D space, orienting objects for assembly, constructing noncontact devices, and assembling objects composed of soft materials such as hydrogels, elastomers, and jammed granular media. PMID:25157136

  16. Noncontact orientation of objects in three-dimensional space using magnetic levitation

    PubMed Central

    Subramaniam, Anand Bala; Yang, Dian; Yu, Hai-Dong; Nemiroski, Alex; Tricard, Simon; Ellerbee, Audrey K.; Soh, Siowling; Whitesides, George M.

    2014-01-01

    This paper describes several noncontact methods of orienting objects in 3D space using Magnetic Levitation (MagLev). The methods use two permanent magnets arranged coaxially with like poles facing and a container containing a paramagnetic liquid in which the objects are suspended. Absent external forcing, objects levitating in the device adopt predictable static orientations; the orientation depends on the shape and distribution of mass within the objects. The orientation of objects of uniform density in the MagLev device shows a sharp geometry-dependent transition: an analytical theory rationalizes this transition and predicts the orientation of objects in the MagLev device. Manipulation of the orientation of the levitating objects in space is achieved in two ways: (i) by rotating and/or translating the MagLev device while the objects are suspended in the paramagnetic solution between the magnets; (ii) by moving a small external magnet close to the levitating objects while keeping the device stationary. Unlike mechanical agitation or robotic selection, orienting using MagLev is possible for objects having a range of different physical characteristics (e.g., different shapes, sizes, and mechanical properties from hard polymers to gels and fluids). MagLev thus has the potential to be useful for sorting and positioning components in 3D space, orienting objects for assembly, constructing noncontact devices, and assembling objects composed of soft materials such as hydrogels, elastomers, and jammed granular media. PMID:25157136

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

    SciTech Connect

    Chang, Chao-Cheng; Hsiao, Po-Jen; You, Jr-Shiang; Chen, Yen-Ju; Chang, Can-Xun

    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. Honey bee orientation: a backup system for cloudy days.

    PubMed

    Dyer, F C; Gould, J L

    1981-11-27

    On cloudy days, honey bees are known to navigate to familiar food sources and orient their dances accurately. This capacity could be based on a magnetic compass sense, an ability to perceive the sun or patterns of polarized light through the clouds, or on the bees' memory of the diurnal course of the sun with respect to local landmarks. Experiments pitting these alternatives against one another demonstrate that the navigational backup system of bees is based on memory.

  19. Compassion: Practical Classroom Activities

    ERIC Educational Resources Information Center

    Wong, Lily; Duffy, Roslyn Ann

    2010-01-01

    Compassion is a deep feeling of sharing the suffering of another. It is a mixture of words, thoughts, and actions that allow a child to be sympathetic to the needs of others. Young children today witness many conflicting values. Values promoted in the media and popular culture often glorify disrespect and unkindness, with beauty and possessions…

  20. [Responsibility, compassion and ethics].

    PubMed

    Furstenberg, Cécile

    2016-01-01

    The concepts of responsibility and compassion are fundamental in ethics. These notions help to safeguard humaneness, especially in the field of health care and notably in palliative care. These concepts can be put into practice by caregivers and applied to daily practice. PMID:27633700

  1. Compassion and Curiosity - TCGA

    Cancer.gov

    William Kim, M.D., is motivated by two things: compassion and curiosity. Dr. Kim has taken these dual motivations and created a career in which he cares directly for patients and spearheads research that may lead to improved treatment options.

  2. Chaos and Compassion.

    ERIC Educational Resources Information Center

    Gelatt, H. B.

    1995-01-01

    Before chaos theory, Western society had no "scientific" tools to deal with disorder and unpredictability because science relied on factual evidence. With chaos theory, knowing and believing are now seen as interconnected and both are considered authentic. Counseling should reflect this authenticity with compassion, not control. (LKS)

  3. Compassion for keeps.

    PubMed

    Trueland, Jennifer

    A three-year programme in Scotland to encourage compassion in every aspect of nursing care drew to a close this summer. However, senior nurses are still involved in the Leadership in Compassionate Care programme, and are determined that its influence will continue to spread across the country.

  4. Piezoelectric Characteristics of Polymer Film Oriented under a Strong Magnetic Field

    NASA Astrophysics Data System (ADS)

    Nakiri, Takuo; Imoto, Kenji; Ishizuka, Masayuki; Okamoto, Satoshi; Date, Munehiro; Uematsu, Yoshiko; Fukada, Eiichi; Tajitsu, Yoshiro

    2004-09-01

    The possibility has been indicated that polymers with helical chirality, such as poly-γ-benzyl-L-glutamate (PBLG) and poly-L-lactic acid (PLLA), exhibit a large shear piezoelectric constant. To attempt the realization of a PBLG membrane with a large piezoelectric constant, we fabricated the PBLG membrane oriented by magnetic field force. Concretely, the PBLG membranes were casted from 1,2-dichloroethane solution with various PBLG concentrations under the magnetic field generation equipment incorporating a superconducting magnet. First, the orientation of the chain molecules of the PBLG membranes obtained was observed macroscopically by means of a polarizing microscope (POM). The orientation of the chain molecules of the PBLG membranes was recognized for the case of casting from the PBLG 1,2-dichloroethane solution in the liquid crystal state. Also, from X-ray photograph measurements, it was found that the orientation direction of the chain molecules of PBLG was perpendicular to the magnetic field direction. We then measured the shear piezoelectric constant d14 of the oriented PBLG membranes. With increasing the strength of the applied magnetic field in the casting process for the film preparation, {d14}* of the PBLG membranes obtained increases. Finally, a large piezoelectric constant of 26 pC/N was found in the PBLG membrane. It is assumed that {d14}* is not saturated even at the magnetic field of 10 T.

  5. Orientation and thickness dependence of magnetization at the interfacesof highly spin-polarized manganite thin films

    SciTech Connect

    Chopdekar, Rajesh V.; Arenholz, Elke; Suzuki, Y.

    2008-08-18

    We have probed the nature of magnetism at the surface of (001), (110) and (111)-oriented La{sub 0.7}Sr{sub 0.3}MnO{sub 3} thin films. The spin polarization of La{sub 0.7}Sr{sub 0.3}MnO{sub 3} thin films is not intrinsically suppressed at all surfaces and interfaces but is highly sensitive to both the epitaxial strain state as well as the substrate orientation. Through the use of soft x-ray spectroscopy, the magnetic properties of (001), (110) and (111)-oriented La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/SrTiO{sub 3} interfaces have been investigated and compared to bulk magnetometry and resistivity measurements. The magnetization of (110) and (111)-oriented La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/SrTiO{sub 3} interfaces are more bulk-like as a function of thickness whereas the magnetization at the (001)-oriented La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/SrTiO{sub 3} interface is suppressed significantly below a layer thickness of 20 nm. Such findings are correlated with the biaxial strain state of the La{sub 0.7}Sr{sub 0.3}MnO{sub 3} films; for a given film thickness it is the tetragonal distortion of (001) La{sub 0.7}Sr{sub 0.3}MnO{sub 3} that severely impacts the magnetization, whereas the trigonal distortion for (111)-oriented films and monoclinic distortion for (110)-oriented films have less of an impact. These observations provide evidence that surface magnetization and thus spin polarization depends strongly on the crystal surface orientation as well as epitaxial strain.

  6. Orientation control of liquid crystals using carbon-nanotube-magnetic particle hybrid materials.

    PubMed

    Jeong, Hyeon Su; Youn, Sang Cheon; Kim, Yun Ho; Jung, Hee-Tae

    2013-06-28

    We have developed a simple yet versatile method for aligning liquid crystals (LCs) by using magnetic-field oriented single-walled carbon nanotubes (SWNTs) that were modified with magnetic particles. A high degree of homeotropic/planar LC alignment was achieved by SWNTs being exposed to a very low strength magnetic field, combined with strong π-π interactions between the biphenyl group in the LCs and the wall of the SWNTs. PMID:23676827

  7. 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

  8. Magnetization-free measurements of spin orientations in orthoferrites using terahertz time domain spectroscopy

    NASA Astrophysics Data System (ADS)

    Suemoto, Tohru; Nakamura, Keita; Kurihara, Takayuki; Watanabe, Hiroshi

    2015-07-01

    The spin orientation during spin reorientation phase transition in a weak ferromagnetic orthoferrite DyxEr1-xFeO3 (x = 0.7) has been studied by using terahertz time domain spectroscopy under zero and weak external magnetic fields. The spin orientation angle was deduced from the ratio of the absorption intensity of quasi-ferromagnetic and quasi-antiferromagnetic modes, which appear around 0.25 and 0.4 THz, respectively. Between 11.4 and 17.9 K, this material showed a rotation-type reorientation transition rather than Morin-type transition. The temperature and magnetic field dependence of the orientation angle of the magnetic moment was found to follow a simple model assuming a linear temperature dependence of the anisotropy parameter. It has been also shown that this method is insensitive to the domain structure with opposite polarity and that it allows measurement without macroscopic magnetization.

  9. 78 FR 35073 - Compass Efficient Model Portfolios, LLC and Compass EMP Funds Trust; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-11

    ... COMMISSION Compass Efficient Model Portfolios, LLC and Compass EMP Funds Trust; Notice of Application June 4.... Applicants: Compass Efficient Model Portfolios, LLC (the ``Adviser'') and Compass EMP Funds Trust (``the... are Compass EMP U.S. 500 Volatility Weighted Fund, Compass EMP U.S. Small Cap 500 Volatility...

  10. Magnetic properties of biaxially oriented Ni-V substrates

    SciTech Connect

    Bettinelli, D.; Petrisor, T.; Gambardella, U.; Boffa, V.; Ceresara, S.; Nistor, L.; Pop, V.; Scardi, P.

    1999-04-20

    The paper presents the structural and magnetic properties of a new non-magnetic biaxially textured substrate based on Ni{sub 100{minus}x}V{sub x} solid-solution for YBa{sub 2}Cu{sub 3}O{sub 7{minus}y} tape fabrication. The effective atomic magnetic moment monotonously decreases with the vanadium concentration, causing a corresponding decrease of Curie temperature. The Curie temperature reaches the zero value at about 11.5% of vanadium. The texturing studies revealed that (100)[-001] cube texture can be easily developed up to x = 11 at.%, by a cold rolling process followed by a recrystallization thermal treatment. The X-ray {omega} and {phi} scans have demonstrated that the samples have a good out-of-plane and in-plane texture for the whole solubility range, with FWHM of 7{degree} and 11{degree}, respectively. The correlation between the magnetic and structural anisotropy was also studied.

  11. Magnetic information affects the stellar orientation of young bird migrants

    NASA Astrophysics Data System (ADS)

    Weindler, Peter; Wiltschko, Roswitha; Wiltschko, Wolfgang

    1996-09-01

    WHEN young birds leave on their first migration, they are guided by innate information about their direction of migration. It is generally assumed that this direction is represented twice, namely with respect to celestial rotation and with respect to the Earth's magnetic field1,2. The interactions between the two cue systems have been analysed by exposing hand-raised young birds during the premigratory period to cue-conflict situations, in which celestial rotation and the magnetic field provided different information. Celestial rotation altered the course with respect to the magnetic field3-7, whereas conflicting magnetic information did not seem to affect the course with respect to the stars8,9. Celestial information thus seemed to dominate over magnetic information. Here we report that the interaction between the two cue systems is far more complex than this. Celestial rotation alone seems to provide only a tendency to move away from its centre (towards geographical south), which is then modified by information from the magnetic field to establish the distinctive, population-specific migratory direction.

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

    PubMed Central

    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

  13. 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.

  14. 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

    2014-10-24

    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. Sensing magnetic directions in birds: radical pair processes involving cryptochrome.

    PubMed

    Wiltschko, Roswitha; Wiltschko, Wolfgang

    2014-09-01

    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.

  16. Sensing magnetic directions in birds: radical pair processes involving cryptochrome.

    PubMed

    Wiltschko, Roswitha; Wiltschko, Wolfgang

    2014-09-01

    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

  17. Electro-optical sun compass with a very high degree of accuracy.

    PubMed

    Bollanti, Sarah; De Meis, Domenico; Di Lazzaro, Paolo; Flora, Francesco; Gallerano, Gian Piero; Mezi, Luca; Murra, Daniele; Torre, Amalia; Vicca, Davide

    2015-08-01

    We present a novel electro-optical solar compass that is able to determine the true North direction with an accuracy better than 1/100 of degree, superior to that of any other magnetic or electronic compass that does not resort to differential GPS. The compass has an electronic sensor to determine the line of sight of the Sun and a simple but effective algorithm to calculate the position of the Sun. The excellent results obtained during the experimental tests demonstrate the advantages of this compass, which is also compact and not expensive. PMID:26258372

  18. Compassion fatigue: a nurse's primer.

    PubMed

    Lombardo, Barbara; Eyre, Caryl

    2011-01-01

    Most nurses enter the field of nursing with the intent to help others and provide empathetic care for patients with critical physical, mental, emotional, and spiritual needs. Empathic and caring nurses, however, can become victims of the continuing stress of meeting the often overwhelming needs of patients and their families, resulting in compassion fatigue. Compassion fatigue affects not only the nurse in terms of job satisfaction and emotional and physical health, but also the workplace environment by decreasing productivity and increasing turnover. We begin this article with a case study of a reactive nurse who did not seek help for her continuing stress. This is followed by a review of Watson's theoretical perspective related to compassion fatigue. Next we delineate symptoms of, and describe interventions for addressing compassion fatigue. We conclude by presenting a case study of a proactive nurse who avoided developing compassion fatigue and a discussion of future research needed to better prevent and ameliorate compassion fatigue. PMID:21800934

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

    SciTech Connect

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

    2015-05-07

    Monodisperse hematite (α-Fe{sub 2}O{sub 3}) nanoparticles were synthesized by forced hydrolysis of acidic Fe{sup 3+} 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°.

  20. 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 (α-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°.

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

    PubMed Central

    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

  2. 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.

  3. Orientation of X Lines in Asymmetric Magnetic Reconnection-Mass Ratio Dependency

    NASA Technical Reports Server (NTRS)

    Liu, Yi-Hsin; Hesse, M.; Kuznetsova, M.

    2015-01-01

    Using fully kinetic simulations, we study the X line orientation of magnetic reconnection in an asymmetric configuration. A spatially localized perturbation is employed to induce a single X line, which has sufficient freedom to choose its orientation in three-dimensional systems. The effect of ion to electron mass ratio is investigated, and the X line appears to bisect the magnetic shear angle across the current sheet in the large mass ratio limit. The orientation can generally be deduced by scanning through the corresponding 2-D simulations to find the reconnection plane that maximizes the peak reconnection electric field. The deviation from the bisection angle in the lower mass ratio limit is consistent with the orientation shift of the most unstable linear tearing mode in an electron-scale current sheet.

  4. Magnetic moment orientation of nano-islands by electrostriction along two directions

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Chen, Y. W.; Cao, J. W.; Wang, T.; Bai, J. M.; Wei, F. L.

    2016-06-01

    This article introduces a new method to realize the 180° magnetic moment reversal of a ferromagnetic and ferroelectric heterostructure through electrostriction-induced magnetic anisotropy. A rectangular magnetic FeAl alloy island with a large magnetostrictive coefficient on a PZN (011) substrate was adopted in our investigation through micromagnetic simulation. Using electrostriction along the [11-1] and [1-11] directions, the magnetic moment was rotated from the long axis of the rectangular island to the direction of the strain and finally reversed to the opposite direction despite the strain sequence. The magnetic moment can be oriented to a certain direction through a certain sequence of strain if a several hundred Oe magnetic field is applied along the short axis of the island. The suitable stress-induced magnetic anisotropy energy and external magnetic field were also investigated. In consideration that a high magnetic field along the short axis leads to small thermal stability of the magnetic moment, the suitable value of stress-induced anisotropy energy is around the critical value where the stress can reverse the magnetic moment without a magnetic field. We compared the stress-induced magnetic reversal processes for same-sized semicircular, elliptical, and rectangular islands and found that the semicircular island can be more easily reversed.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. Predicting epitaxial orientations and lattice structure in ultrathin magnetic thin films

    NASA Astrophysics Data System (ADS)

    Lu, Yong; Wang, Cuiping; Shi, Rongpei; Cui, Yuanyuan; Shi, Zhan; Yang, Shuiyuan; Cui, Yuwen; Liu, Xingjun

    2016-07-01

    Metastable phases, such as bcc Co or Ni and hcp Fe or Ni, reportedly possess extraordinary magnetic properties for epitaxial ultra-thin films. To understand phase stability of these epitaxy-oriented phases upon substrate lattices, we calculated novel phase diagrams of Co, Fe, and Ni ultrathin films by considering the chemical free energy, elastic strain energy, and surface energy. Verified by experimental data in the literatures, the stable epitaxy-oriented phases are readily identified from the phase diagrams. The stabilization of these metastable phases is determined by the interplay between orientation-dependent elastic strain energy and surface energy.

  10. Magnetic field orientations in Saturn's upper ionosphere inferred from Voyager radio occultations

    NASA Technical Reports Server (NTRS)

    Hinson, D. P.

    1984-01-01

    The radio scintillations observed during occultations of Voyagers 1 and 2 by Saturn are analyzed to determine the morphology of plasma irregularities and hence the magnetic field orientation in Saturn's upper atmosphere. The measurement techniques, the weak scattering theory, and the method used to relate the observed radio scintillations to physical properties of the ionospheric irregularities are briefly described. Results on the spatial characteristics of the irregularities are presented, and the magnetic field orientation in Saturn's ionosphere is inferred. Although the occultation measurements generally confirm the accuracy of the Saturnian magnetic field model of Connerney et al. (1982), it is found that a small adjustment of the coefficients in that model's zonal harmonic expansion would remove the discrepancy between the model predictions and the measurements. A strategy for obtaining improved measurements of Saturn's magnetic field from radio occultation observations of scintillations and Faraday rotation using an orbiting spacecraft is briefly discussed.

  11. Orientational flow in monodomain samples of the smectic-F phase: Deuterium nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Figueirinhas, J.; Umer, S.; Doane, J. W.

    1987-05-01

    Monodomain samples of the SF and SG liquid crystalline phases were studied to determine the orientation of the principal-axes system of the time-averaged field gradient tensors for various deuterated sites in the compound 4-n-nonoxybenzylidene-4'-butylaniline(9O.4). The monodomain samples were prepared by cooling an aligned SA sample, suitably oriented in a 4.7 T magnetic field, into the SF and SG phases. Studies of the angular dependence of the deuterium spectra show a different orientation for the principal axes of the averaged field gradient tensor from deuterated sites on the molecular core and the chain. In the SF phase it was discovered that while the direction of tilt could switch its orientation in the presence of a field, so could the principal axes associated with deuterated sites on the molecular core and chain but each under different field orientation. Orientational flow imposed by the magnetic field is clearly different for the core and chain sublattices. Magnitudes of tilt angles, the averaged quadrupole coupling constant ν¯Q, and asymmetry parameter η¯ are measured. Based on these values a molecular model for the SF phase composed of two distinct sublattices, one formed by the aliphatic chains showing no in-plane orientational order and the other formed by the aromatic cores showing local herringbone order, are proposed.

  12. Understanding compassion literacy in nursing through a clinical compassion cafe.

    PubMed

    Winch, Sarah; Henderson, Amanda Jane; Kay, Margaret; Burridge, Letitia Helen; Livesay, Georgia Jane; Sinnott, Michael John

    2014-11-01

    This article presents a method of reconnecting and reaffirming with nurses the importance of compassion in health care by using a clinical compassion cafe, which describes nine steps that provide a forum to reaffirm clinicians' core values. This process has the potential to engage clinical staff in a different modality removed from the usual didactic approaches.

  13. The effect of interplanetary magnetic field orientation on the solar wind flux impacting Mercury's surface

    NASA Astrophysics Data System (ADS)

    Varela, J.; Pantellini, F.; Moncuquet, M.

    2015-12-01

    The aim of this paper is to study the plasma flows on the Mercury surface for different interplanetary magnetic field orientations on the day side of the planet. We use a single fluid MHD model in spherical coordinates to simulate the interaction of the solar wind with the Hermean magnetosphere for six solar wind realistic configurations with different magnetic field orientations: Mercury-Sun, Sun-Mercury, aligned with the magnetic axis of Mercury (Northward and Southward) and with the orbital plane perpendicular to the previous cases. In the Mercury-Sun (Sun-Mercury) simulation the Hermean magnetic field is weakened in the South-East (North-East) of the magnetosphere leading to an enhancement of the flows on the South (North) hemisphere. For a Northward (Southward) orientation there is an enhancement (weakening) of the Hermean magnetic field in the nose of the bow shock so the fluxes are reduced and drifted to the poles (enhanced and drifted to the equator). If the solar wind magnetic field is in the orbital plane the magnetosphere is tilted to the West (East) and weakened at the nose of the shock, so the flows are enhanced and drifted to the East (West) in the Northern hemisphere and to the West (East) in the Southern hemisphere.

  14. Bunker probe: A plasma potential probe almost insensitive to its orientation with the magnetic field.

    PubMed

    Costea, S; Fonda, B; Kovačič, J; Gyergyek, T; Schneider, B S; Schrittwieser, R; Ionita, C

    2016-05-01

    Due to their ability to suppress a large part of the electron current and thus measuring directly the plasma potential, ion sensitive probes have begun to be widely tested and used in fusion devices. For these probes to work, almost perfect alignment with the total magnetic field is necessary. This condition cannot always be fulfilled due to the curvature of magnetic fields, complex magnetic structure, or magnetic field reconnection. In this perspective, we have developed a plasma potential probe (named Bunker probe) based on the principle of the ion sensitive probe but almost insensitive to its orientation with the total magnetic field. Therefore it can be used to measure the plasma potential inside fusion devices, especially in regions with complex magnetic field topology. Experimental results are presented and compared with Ball-Pen probe measurements taken under identical conditions. We have observed that the floating potential of the Bunker probe is indeed little affected by its orientation with the magnetic field for angles ranging from 90° to 30°, in contrast to the Ball-Pen probe whose floating potential decreases towards that of a Langmuir probe if not properly aligned with the magnetic field. PMID:27250426

  15. Bunker probe: A plasma potential probe almost insensitive to its orientation with the magnetic field.

    PubMed

    Costea, S; Fonda, B; Kovačič, J; Gyergyek, T; Schneider, B S; Schrittwieser, R; Ionita, C

    2016-05-01

    Due to their ability to suppress a large part of the electron current and thus measuring directly the plasma potential, ion sensitive probes have begun to be widely tested and used in fusion devices. For these probes to work, almost perfect alignment with the total magnetic field is necessary. This condition cannot always be fulfilled due to the curvature of magnetic fields, complex magnetic structure, or magnetic field reconnection. In this perspective, we have developed a plasma potential probe (named Bunker probe) based on the principle of the ion sensitive probe but almost insensitive to its orientation with the total magnetic field. Therefore it can be used to measure the plasma potential inside fusion devices, especially in regions with complex magnetic field topology. Experimental results are presented and compared with Ball-Pen probe measurements taken under identical conditions. We have observed that the floating potential of the Bunker probe is indeed little affected by its orientation with the magnetic field for angles ranging from 90° to 30°, in contrast to the Ball-Pen probe whose floating potential decreases towards that of a Langmuir probe if not properly aligned with the magnetic field.

  16. Orientation and Pore-Forming Mechanism of a Scorpion Pore-Forming Peptide Bound to Magnetically Oriented Lipid Bilayers

    PubMed Central

    Nomura, Kaoru; Corzo, Gerardo; Nakajima, Terumi; Iwashita, Takashi

    2004-01-01

    The orientation and pore-forming mechanisms of pandinin 2 (pin2), an antimicrobial peptide isolated from venom of the African scorpion Pandinus imperator, bound to magnetically oriented lipid bilayers were examined by 31P and 13C solid-state, and 15N liquid-state NMR spectroscopy. 31P NMR measurements at various temperatures, under neutral and acidic conditions, showed that membrane lysis occurred only under acidic conditions, and at temperatures below the liquid crystal-gel phase transition of the lipid bilayers, after incubation for two days in the magnet. Differential scanning calorimetry measurements showed that pin2 induced negative curvature strain in lipid bilayers. The 13C chemical shift values of synthetic pin2 labeled at Gly3, Gly8, Leu12, Phe17, or Ser18 under static or slow magic-angle spinning conditions, indicate that pin2 penetrates the membrane with its average helical axis perpendicular to the membrane surface. Furthermore, amide H-D exchange experiments of 15N-Ala4, Gly8, and Ala9 triply-labeled pin2 suggest that this peptide forms oligomers and confirms that the N-terminal region creates membrane pores. PMID:15298871

  17. Cultivating Compassion: Rhetoric or Reality?

    ERIC Educational Resources Information Center

    Lovette-Colyer, Michael

    2014-01-01

    Despite the massive amounts of research conducted on the effect of college on students, almost no empirical work has been done on whether students grow in compassion during their undergraduate studies. Designed to address this gap, this longitudinal study of more than 500 students found that the majority demonstrated change in compassion across…

  18. ORIENTATION REQUIREMENT TO DETECT MAGNETIC FIELD-INDUCTED ALTERATION OF GAP JUNCTION COMMUNICATION IN EPITHELIAL CELLS

    EPA Science Inventory

    ORIENTATION REQUIREMENT TO DETECT MAGNETIC FIELD-INDUCED ALTERATION OF GAP JUNCTION COMMUNICATION IN EPITHELIAL CELLS.
    OBJECTIVE: We have shown that functional gap junction communication as measured by Lucifer yellow dye transfer (DT) in Clone-9 rat liver epithelial cells, c...

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

    SciTech Connect

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

    2015-06-07

    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.

  20. 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.

    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.

  1. Connecting for compassion.

    PubMed

    Ménage, Diane

    2015-03-01

    On a mission to promote compassion in midwifery practice I was looking for effective methods of sharing and developing my ideas. I recognised the benefits of networking through more traditional methods but was not really utilising social media. Then another midwife encouraged me to use Twitter. Although not particularly confident with social media and unsure about how it could support me professionally, I decided to try it. Six months later I have some new skills and I am part of a dynamic and stimulating online community. This article is a personal account of that learning journey in which I reflect on some of the benefits that I have discovered so far. PMID:26349330

  2. 46 CFR 130.340 - Compass.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Compass. 130.340 Section 130.340 Shipping COAST GUARD... EQUIPMENT AND SYSTEMS Navigational Equipment § 130.340 Compass. Each vessel must be fitted with a compass... compass must be illuminated....

  3. 46 CFR 130.340 - Compass.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Compass. 130.340 Section 130.340 Shipping COAST GUARD... EQUIPMENT AND SYSTEMS Navigational Equipment § 130.340 Compass. Each vessel must be fitted with a compass... compass must be illuminated....

  4. 46 CFR 130.340 - Compass.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Compass. 130.340 Section 130.340 Shipping COAST GUARD... EQUIPMENT AND SYSTEMS Navigational Equipment § 130.340 Compass. Each vessel must be fitted with a compass... compass must be illuminated....

  5. 46 CFR 130.340 - Compass.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Compass. 130.340 Section 130.340 Shipping COAST GUARD... EQUIPMENT AND SYSTEMS Navigational Equipment § 130.340 Compass. Each vessel must be fitted with a compass... compass must be illuminated....

  6. 46 CFR 130.340 - Compass.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Compass. 130.340 Section 130.340 Shipping COAST GUARD... EQUIPMENT AND SYSTEMS Navigational Equipment § 130.340 Compass. Each vessel must be fitted with a compass... compass must be illuminated....

  7. Interface deformations affect the orientation transition of magnetic ellipsoidal particles adsorbed at fluid-fluid interfaces.

    PubMed

    Davies, Gary B; Krüger, Timm; Coveney, Peter V; Harting, Jens; Bresme, Fernando

    2014-09-21

    Manufacturing new soft materials with specific optical, mechanical and magnetic properties is a significant challenge. Assembling and manipulating colloidal particles at fluid interfaces is a promising way to make such materials. We use lattice-Boltzmann simulations to investigate the response of magnetic ellipsoidal particles adsorbed at liquid-liquid interfaces to external magnetic fields. We provide further evidence for the first-order orientation phase transition predicted by Bresme and Faraudo [Journal of Physics: Condensed Matter, 2007, 19, 375110]. We show that capillary interface deformations around the ellipsoidal particle significantly affect the tilt-angle of the particle for a given dipole-field strength, altering the properties of the orientation transition. We propose scaling laws governing this transition, and suggest how to use these deformations to facilitate particle assembly at fluid-fluid interfaces. PMID:25069609

  8. Interface deformations affect the orientation transition of magnetic ellipsoidal particles adsorbed at fluid-fluid interfaces.

    PubMed

    Davies, Gary B; Krüger, Timm; Coveney, Peter V; Harting, Jens; Bresme, Fernando

    2014-09-21

    Manufacturing new soft materials with specific optical, mechanical and magnetic properties is a significant challenge. Assembling and manipulating colloidal particles at fluid interfaces is a promising way to make such materials. We use lattice-Boltzmann simulations to investigate the response of magnetic ellipsoidal particles adsorbed at liquid-liquid interfaces to external magnetic fields. We provide further evidence for the first-order orientation phase transition predicted by Bresme and Faraudo [Journal of Physics: Condensed Matter, 2007, 19, 375110]. We show that capillary interface deformations around the ellipsoidal particle significantly affect the tilt-angle of the particle for a given dipole-field strength, altering the properties of the orientation transition. We propose scaling laws governing this transition, and suggest how to use these deformations to facilitate particle assembly at fluid-fluid interfaces.

  9. Orientational order and translational dynamics of magnetic particle assemblies in liquid crystals.

    PubMed

    Peroukidis, Stavros D; Klapp, Sabine H L

    2016-08-10

    Implementing extensive molecular dynamics simulations we explore the organization of magnetic particle assemblies (clusters) in a uniaxial liquid crystalline matrix comprised of rodlike particles. The magnetic particles are modelled as soft dipolar spheres with diameter significantly smaller than the width of the rods. Depending on the dipolar strength coupling the magnetic particles arrange into head-to-tail configurations forming various types of clusters including rings (closed loops) and chains. In turn, the liquid crystalline matrix induces long range orientational ordering to these structures and promotes their diffusion along the director of the phase. Different translational dynamics are exhibited as the liquid crystalline matrix transforms either from isotropic to nematic or from nematic to smectic state. This is caused due to different collective motion of the magnetic particles into various clusters in the anisotropic environments. Our results offer a physical insight for understanding both the structure and dynamics of magnetic particle assemblies in liquid crystalline matrices.

  10. Orientational order and translational dynamics of magnetic particle assemblies in liquid crystals.

    PubMed

    Peroukidis, Stavros D; Klapp, Sabine H L

    2016-08-10

    Implementing extensive molecular dynamics simulations we explore the organization of magnetic particle assemblies (clusters) in a uniaxial liquid crystalline matrix comprised of rodlike particles. The magnetic particles are modelled as soft dipolar spheres with diameter significantly smaller than the width of the rods. Depending on the dipolar strength coupling the magnetic particles arrange into head-to-tail configurations forming various types of clusters including rings (closed loops) and chains. In turn, the liquid crystalline matrix induces long range orientational ordering to these structures and promotes their diffusion along the director of the phase. Different translational dynamics are exhibited as the liquid crystalline matrix transforms either from isotropic to nematic or from nematic to smectic state. This is caused due to different collective motion of the magnetic particles into various clusters in the anisotropic environments. Our results offer a physical insight for understanding both the structure and dynamics of magnetic particle assemblies in liquid crystalline matrices. PMID:27460190

  11. Orientational dynamics of a ferronematic liquid crystal in a rotating magnetic field

    SciTech Connect

    Boychuk, A. N. Zakhlevnykh, A. N.; Makarov, D. V.

    2015-09-15

    The behavior of the orientational structure of a ferronematic in a rotating uniform magnetic field is investigated using the continual theory. The time-dependent system of equations describing the dynamics of the ferronematic is derived. The dependences of the angles of rotation of the director and of the magnetization of the ferronematic on the velocity of field rotation are determined for various values of the material parameters. Two regimes (synchronous and asynchronous) of rotation of the ferronematic structure are detected. In the synchronous regime, the director rotates with the frequency of the magnetic field and a constant phase delay. The asynchronous regime is characterized by a time-dependent phase delay. The dependence of the critical angular velocity of magnetic field rotation, which determines the boundary between the synchronous and asynchronous regimes, on the magnetic field strength is derived.

  12. 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.

  13. Biophysics of Magnetic Orientation: Radical Pairs, Biogenic Magnetite, or both?

    NASA Astrophysics Data System (ADS)

    Kirschvink, Joe

    2011-03-01

    Two major biophysical mechanisms for magnetoreception in terrestrial animals, one based on biogenic magnetite and another on radical-pair biochemical reactions, have been the subject of experiment and debate for the past 30 years. The magnetite hypothesis has stood the test of time: biogenic magnetite is synthesized biochemically in Bacteria, Protists, and numerous Animal phyla, as well as in some plants. Chains of single-domain crystals have been detected by clean-lab based SQUID magnetometry in animal tissues in all major phyla, followed by high-resolution TEM in selected model organisms, as well as by electrophysiological studies demonstrating the role of the ophthalmic branch of the trigeminal nerve in the magnetoreceptive process. Pulse-remagnetization - configured to uniquely flip the polarity of single-domain ferromagnets - has dramatic effects on the behavior of many birds, honeybees, mole rats, turtles, and bats, to cite a growing list. Magnetite-containing cells in the vicinity of these neurons in fish are now the subject of intense study by our consortium. The existence of a specialized class of magnetite-containing magnetoreceptor cells in animal tissues is no longer controversial. In contrast, less success has been achieved in gaining experimental support across a range of taxa for the radical-pair hypothesis. Although this mechanism was proposed to explain an early observation that birds would not respond to complete inversion of the magnetic vector, many organisms (even some birds) do indeed respond to the field polarity. We also note that few, if any, of these critical experiments have been done using fully double-blind methods. This is joint work with: M. M. Walker (University of Auckland, New Zealand) and M. Winklhofer (LMU Munich, Germany).

  14. The orientation of the neuronal growth process can be directed via magnetic nanoparticles under an applied magnetic field.

    PubMed

    Riggio, Cristina; Calatayud, M Pilar; Giannaccini, Martina; Sanz, Beatriz; Torres, Teobaldo E; Fernández-Pacheco, Rodrigo; Ripoli, Andrea; Ibarra, Manuel Ricardo; Dente, Luciana; Cuschieri, Alfred; Goya, Gerardo F; Raffa, Vittoria

    2014-10-01

    There is a growing body of evidence indicating the importance of physical stimuli for neuronal growth and development. Specifically, results from published experimental studies indicate that forces, when carefully controlled, can modulate neuronal regeneration. Here, we validate a non-invasive approach for physical guidance of nerve regeneration based on the synergic use of magnetic nanoparticles (MNPs) and magnetic fields (Ms). The concept is that the application of a tensile force to a neuronal cell can stimulate neurite initiation or axon elongation in the desired direction, the MNPs being used to generate this tensile force under the effect of a static external magnetic field providing the required directional orientation. In a neuron-like cell line, we have confirmed that MNPs direct the neurite outgrowth preferentially along the direction imposed by an external magnetic field, by inducing a net angle displacement (about 30°) of neurite direction. From the clinical editor: This study validates that non-invasive approaches for physical guidance of nerve regeneration based on the synergic use of magnetic nanoparticles and magnetic fields are possible. The hypothesis was confirmed by observing preferential neurite outgrowth in a cell culture system along the direction imposed by an external magnetic field.

  15. Orientational control of block copolymer microdomains by sub-tesla magnetic fields

    NASA Astrophysics Data System (ADS)

    Gopinadhan, Manesh; Choo, Youngwoo; Feng, Xunda; Kawabata, Kohsuke; di, Xiaojun; Osuji, Chinedum

    Magnetic fields offer a versatile approach to controlling the orientation of block copolymer (BCP) microdomains during self-assembly. To date however, such control has required the imposition of large magnetic fields (>3T), necessitating the use of complex magnet systems - either superconducting or very large conventional resistive magnets. Here we demonstrate the ability to direct BCP self-assembly using considerably smaller fields (<1T) which are accessible using simple rare-earth permanent magnets. The low field alignment is enabled by the presence of small quantities of mesogenic species that are blended into, and co-assemble with the liquid crystalline (LC) mesophase of the side-chain LC BCP under study. In situ SAXS experiments reveal a pronounced dependence of the critical alignment field strength on the stoichiometry of the blend, and the ability to generate aligned microdomains with orientational distribution coefficients exceeding 0.95 at sub-1 T fields for appropriate stoichiometries. The alignment response overall can be rationalized in terms of increased mobility and grain size due to the presence of the mesogenic additive. We use a permanent magnet to fabricate films with aligned nanopores, and the utility of this approach to generate complex BCP microdomain patterns in thin films by local field screening are highlighted. NSF DMR-1410568 and DMR-0847534.

  16. Anomalous Magnetic Orientations of Magnetosome Chains in a Magnetotactic Bacterium: Magnetovibrio blakemorei Strain MV-1

    PubMed Central

    Kalirai, Samanbir S.; Bazylinski, Dennis A.; Hitchcock, Adam P.

    2013-01-01

    There is a good deal of published evidence that indicates that all magnetosomes within a single cell of a magnetotactic bacterium are magnetically oriented in the same direction so that they form a single magnetic dipole believed to assist navigation of the cell to optimal environments for their growth and survival. Some cells of the cultured magnetotactic bacterium Magnetovibrio blakemorei strain MV-1 are known to have relatively wide gaps between groups of magnetosomes that do not seem to interfere with the larger, overall linear arrangement of the magnetosomes along the long axis of the cell. We determined the magnetic orientation of the magnetosomes in individual cells of this bacterium using Fe 2p X-ray magnetic circular dichroism (XMCD) spectra measured with scanning transmission X-ray microscopy (STXM). We observed a significant number of cases in which there are sub-chains in a single cell, with spatial gaps between them, in which one or more sub-chains are magnetically polarized opposite to other sub-chains in the same cell. These occur with an estimated frequency of 4.0±0.2%, based on a sample size of 150 cells. We propose possible explanations for these anomalous cases which shed insight into the mechanisms of chain formation and magnetic alignment. PMID:23308202

  17. Magnetization-free measurements of spin orientations in orthoferrites using terahertz time domain spectroscopy

    SciTech Connect

    Suemoto, Tohru Nakamura, Keita; Kurihara, Takayuki; Watanabe, Hiroshi

    2015-07-27

    The spin orientation during spin reorientation phase transition in a weak ferromagnetic orthoferrite Dy{sub x}Er{sub 1−x}FeO{sub 3} (x = 0.7) has been studied by using terahertz time domain spectroscopy under zero and weak external magnetic fields. The spin orientation angle was deduced from the ratio of the absorption intensity of quasi-ferromagnetic and quasi-antiferromagnetic modes, which appear around 0.25 and 0.4 THz, respectively. Between 11.4 and 17.9 K, this material showed a rotation-type reorientation transition rather than Morin-type transition. The temperature and magnetic field dependence of the orientation angle of the magnetic moment was found to follow a simple model assuming a linear temperature dependence of the anisotropy parameter. It has been also shown that this method is insensitive to the domain structure with opposite polarity and that it allows measurement without macroscopic magnetization.

  18. Crystal-oriented tungsten-bronze type ceramics prepared by a rotating magnetic field

    NASA Astrophysics Data System (ADS)

    Tanaka, S.; Doshida, Y.; Shimizu, H.; Furushima, R.; Uematsu, K.

    2011-03-01

    Forming and sintering of c-axis-oriented Sr2NaNb5O15 (SNN) ceramics were examined. Particle-oriented SNN was fabricated by using a rotating high magnetic field and subsequent sintering without magnetic field. SNN ceramics are tungsten-bronze-type ferroelectric materials with a tetragonal crystal system. The diamagnetic susceptibilities of the c-axis are smaller than that of the a- and b-axis (χc < χa,b < 0). SNN powder was prepared by conventional solid-state reaction. The synthesized powder was mixed with distilled water and a dispersant by using ball milling to give a slurry with solid loading of 30 vol%. The slurry was poured into a plastic mold and this was placed in a 10Tesla magnetic field in a superconducting magnet. The mold was rotated at 30 rpm while the slurry dried at room temperature. The resulting powder compact with a columnar shape was heated at 5 K/min to 1473 K, held for 6 h, and then heated at 1525 K for 2 h to prevent exaggerated grain growth. XRD patterns showed that c-axis-oriented SNN polycrystalline ceramics were produced in the presence of the rotating magnetic field. In XRD patterns viewed from the top surface of the sintered specimens, peaks from the c-planes of the crystal, such as 001 and 002, were very strong. Diffraction peaks which were very strong in the ceramics, such as 320 and 410, were absent in the specimen. Oriented microstructure was developed well by sintering. Grain-growth along to c-axis was observed in the SNN ceramics heated at 1525 K.

  19. Charmed hadron photoproduction at COMPASS

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Yun; Guskov, Alexey

    2016-06-01

    Photoproduction of the charmonium-like state Zc(4200) and the charmed baryon Λ_c^* (2940) is investigated with an effective Lagrangian approach and the Regge trajectories applying to the COMPASS experiment. Combining the experimental data from COMPASS and our theoretical model we estimate the upper limit of ΓZc(4200)→J/ψπ to be of about 37 MeV. Moreover, the possibility to produce Λ_c^* (2940) at COMPASS is discussed. It seems one can try to search for this hadron in the missing mass spectrum since the t-channel is dominating for the Λ_c^* (2940) photoproduction.

  20. Magnetic orientation of nontronite clay in aqueous dispersions and its effect on water diffusion.

    PubMed

    Abrahamsson, Christoffer; Nordstierna, Lars; Nordin, Matias; Dvinskikh, Sergey V; Nydén, Magnus

    2015-01-01

    The diffusion rate of water in dilute clay dispersions depends on particle concentration, size, shape, aggregation and water-particle interactions. As nontronite clay particles magnetically align parallel to the magnetic field, directional self-diffusion anisotropy can be created within such dispersion. Here we study water diffusion in exfoliated nontronite clay dispersions by diffusion NMR and time-dependant 1H-NMR-imaging profiles. The dispersion clay concentration was varied between 0.3 and 0.7 vol%. After magnetic alignment of the clay particles in these dispersions a maximum difference of 20% was measured between the parallel and perpendicular self-diffusion coefficients in the dispersion with 0.7 vol% clay. A method was developed to measure water diffusion within the dispersion in the absence of a magnetic field (random clay orientation) as this is not possible with standard diffusion NMR. However, no significant difference in self-diffusion coefficient between random and aligned dispersions could be observed.

  1. 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.

  2. 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.

  3. 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.

  4. The relative orientation between the magnetic field and structures traced by interstellar dust

    NASA Astrophysics Data System (ADS)

    Bracco, Andrea; Planck Collaboration

    2015-01-01

    The role of the magnetic field in the formation of the filamentary structures observed in the interstellar medium (ISM) is a debated topic. The Planck all-sky maps of linearly polarized emission from dust at 353GHz provide the required combination of imaging and statistics to study the correlation between the structures of the Galactic magnetic field and of interstellar matter, both in the diffuse ISM and in molecular clouds. The data reveal structures, or ridges, in the intensity map with counterparts in the Stokes Q and/or U maps. We focus on structures at intermediate and high Galactic latitudes with column density from 10^20 to 10^22 cm^-2. We measure the magnetic field orientation on the plane of the sky from the polarization data, and present an algorithm to estimate the orientation of the ridges from the dust intensity map. We use analytical models to account for projection effects. Comparing polarization angles on and off the structures, we estimate the mean ratio between the strengths of the turbulent and mean components of the magnetic field to be between 0.6 and 1.0, with a preferred value of 0.8. We find that the ridges are preferentially aligned with the magnetic field measured on the structures. This trend becomes more striking for increasing polarization fraction and decreasing column density. We interpret the increase of alignment with polarization fraction as a consequence of projections effects. The decrease of alignment for high column density is not due to a loss of correlation between the structures and the geometry of the magnetic field. In molecular complexes, we observe structures perpendicular to the magnetic field, which cannot be accounted for by projection effects. We discuss our results in the context of models and MHD simulations, which describe the formation of structures in the magnetized ISM.

  5. Orientation of migratory birds under ultraviolet light.

    PubMed

    Wiltschko, Roswitha; Munro, Ursula; Ford, Hugh; Stapput, Katrin; Thalau, Peter; Wiltschko, Wolfgang

    2014-05-01

    In view of the finding that cryptochrome 1a, the putative receptor molecule for the avian magnetic compass, is restricted to the ultraviolet single cones in European Robins, we studied the orientation behaviour of robins and Australian Silvereyes under monochromatic ultraviolet (UV) light. At low intensity UV light of 0.3 mW/m(2), birds showed normal migratory orientation by their inclination compass, with the directional information originating in radical pair processes in the eye. At 2.8 mW/m(2), robins showed an axial preference in the east-west axis, whereas silvereyes preferred an easterly direction. At 5.7 mW/m(2), robins changed direction to a north-south axis. When UV light was combined with yellow light, robins showed easterly 'fixed direction' responses, which changed to disorientation when their upper beak was locally anaesthetised with xylocaine, indicating that they were controlled by the magnetite-based receptors in the beak. Orientation under UV light thus appears to be similar to that observed under blue, turquoise and green light, albeit the UV responses occur at lower light levels, probably because of the greater light sensitivity of the UV cones. The orientation under UV light and green light suggests that at least at the level of the retina, magnetoreception and vision are largely independent of each other.

  6. Orientation of migratory birds under ultraviolet light.

    PubMed

    Wiltschko, Roswitha; Munro, Ursula; Ford, Hugh; Stapput, Katrin; Thalau, Peter; Wiltschko, Wolfgang

    2014-05-01

    In view of the finding that cryptochrome 1a, the putative receptor molecule for the avian magnetic compass, is restricted to the ultraviolet single cones in European Robins, we studied the orientation behaviour of robins and Australian Silvereyes under monochromatic ultraviolet (UV) light. At low intensity UV light of 0.3 mW/m(2), birds showed normal migratory orientation by their inclination compass, with the directional information originating in radical pair processes in the eye. At 2.8 mW/m(2), robins showed an axial preference in the east-west axis, whereas silvereyes preferred an easterly direction. At 5.7 mW/m(2), robins changed direction to a north-south axis. When UV light was combined with yellow light, robins showed easterly 'fixed direction' responses, which changed to disorientation when their upper beak was locally anaesthetised with xylocaine, indicating that they were controlled by the magnetite-based receptors in the beak. Orientation under UV light thus appears to be similar to that observed under blue, turquoise and green light, albeit the UV responses occur at lower light levels, probably because of the greater light sensitivity of the UV cones. The orientation under UV light and green light suggests that at least at the level of the retina, magnetoreception and vision are largely independent of each other. PMID:24718656

  7. 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.

  8. Orientation measurement based on magnetic inductance by the extended distributed multi-pole model.

    PubMed

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

    2014-06-27

    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.

  9. 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

  10. Magnetic and transport properties of Mn{sub 2}CoAl oriented films

    SciTech Connect

    Jamer, Michelle E.; Assaf, Badih A.; Devakul, Trithep; Heiman, Don

    2013-09-30

    The structure, magnetic, and transport properties of thin films of the Heusler ferrimagnet Mn{sub 2}CoAl have been investigated for properties related to spin gapless semiconductors. Oriented films were grown by molecular beam epitaxy on GaAs substrates and the structure was found to transform from tetragonal to cubic for increasing annealing temperature. The anomalous Hall resistivity is found to be proportional to the square of the longitudinal resistivity and magnetization expected for a topological Berry curvature origin. A delicate balance of the spin-polarized carrier type when coupled with voltage gate-tuning could significantly impact advanced electronic devices.

  11. 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.

  12. Electronic transport properties and orientation of individual Mn12 single-molecule magnets

    NASA Astrophysics Data System (ADS)

    Voss, S.; Zander, O.; Fonin, M.; Rüdiger, U.; Burgert, M.; Groth, U.

    2008-10-01

    Individual Mn12 single-molecule magnets have been investigated by means of scanning tunneling spectroscopy at room temperature. Current-voltage characteristics of a Mn12 derivative are studied in detail and compared with simulations. A few-parameter scalar model for ballistic current flow through a single energy level is sufficient to describe the main features observed in scanning tunneling spectra of individual Mn12 molecules and offers a deeper insight into the electronic transport properties of this class of single-molecule magnets. In addition, distance-voltage spectroscopy performed on individual Mn12 molecules reveals a possibility to identify the orientation of the molecular easy axis. The results indicate a preferential orientation of the easy axis of the molecules nearly perpendicular to the surface.

  13. The effects of interplanetary magnetic field orientation on dayside high-latitude ionospheric convection

    NASA Technical Reports Server (NTRS)

    Heelis, R. A.

    1984-01-01

    The Atmosphere Explorer C data base of Northern Hemisphere ionospheric convection signatures at high latitudes is examined during times when the interplanetary magnetic field orientation is relatively stable. It is found that when the interplanetary magnetic field (IMF) has its expected garden hose orientation, the center of a region where the ion flow rotates from sunward to antisunward is displaced from local noon toward dawn irrespective of the sign of By. Poleward of this rotation region, called the cleft, the ion convection is directed toward dawn or dusk depending on whether By is positive or negative, respectively. The observed flow geometry can be explained in terms of a magnetosphere solar wind interaction in which merging is favored in either the prenoon Northern Hemisphere or the prenoon Southern Hemisphere when the IMF has a normal sector structure that is toward or away, respectively.

  14. Development of the Shielding Materials Having the Highly Orientation Characteristics in the RF Magnetic Field

    NASA Astrophysics Data System (ADS)

    Nishikubo, Tokoh; Itoh, Mineo

    The conventional electromagnetic shielding technique is all but impossible to fundamental solution of the problems in the information and communication fields, such as virtual image for radar. Namely, it is necessary to receive a required electromagnetic wave as the information signal, and to shield a needless electromagnetic wave as the noise. the present research has developed the carbon, copper, ferrite, and BPSCCO plates, as the typical shielding material, having the orientation characteristics in the RF (radio frequency) magnetic field. To exhibit the orientation characteristics in the plane wave, it has formed the slit on the surface of typical shielding materials; termed the slit plate. For example, the value of RF magnetic shielding degree SDHP of slit carbon plate for holding the slit perpendicularly to the ground increased with frequency in the region from 1 MHz (7 dB) to 3 GHz (70 dB). And, the value of SDHH when holding the slit horizontally is indicated an average value of approximately 10 dB in this frequency region. That is, the difference values, SDHP-SDHH, indicated the orientation characteristics. Experimental results revealed several characteristics of the slit plates that include the influences of orientation characteristics on the slit length, slit width, and slit number. In the present paper, it was succeeded to improved the difference average value of approximately 35 dB for SDHP-SDHH, by the sandwich of slit ferrite plate over a slit carbon plate, in the civilian communication frequency region from 1 MHz to 3 GHz. In addition, important criteria are discussed for the design of an effective RF magnetic shielding plate having orientation characteristics.

  15. Self-organisation, orientation and magnetic properties of FePt nanoparticle arrays

    NASA Astrophysics Data System (ADS)

    Verdes, C.; Chantrell, R. W.; Satoh, A.; Harrell, J. W.; Nikles, D.

    2006-09-01

    Self-organised magnetic arrays (SOMA) of high anisotropy particles are a promising candidate for ultra-high-density recording media. In principle SOMA media have the capability of storing 1 bit per particle, leading to possible reecording densities in excess of 10 Tbit/sq in. In this paper we consider two major aspects of SOMA media, namely the self-organisation process itself and the physics of the particle orientation process.

  16. Orientational dynamics of colloidal ribbons self-assembled from microscopic magnetic ellipsoids.

    PubMed

    Martinez-Pedrero, Fernando; Cebers, Andrejs; Tierno, Pietro

    2016-04-20

    We combine experiments and theory to investigate the orientational dynamics of dipolar ellipsoids, which self-assemble into elongated ribbon-like structures due to the presence of a permanent magnetic moment, perpendicular to the long axis in each particle. Monodisperse hematite ellipsoids are synthesized via the sol-gel technique and arrange into ribbons in the presence of static or time-dependent magnetic fields. We find that under an oscillating field, the ribbons reorient perpendicular to the field direction, in contrast with the behaviour observed under a static field. This observation is explained theoretically by treating a chain of interacting ellipsoids as a single particle with orientational and demagnetizing field energy. The model allows us to describe the orientational behaviour of the chain and captures well its dynamics at different strengths of the actuating field. The understanding of the complex dynamics and assembly of anisotropic magnetic colloids is a necessary step for controlling the structure formation, which has direct applications in different fluid-based microscale technologies. PMID:26936015

  17. 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.

  18. 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

  19. The orientation of membrane bound radicals: an EPR investigation of magnetically ordered spinach chloroplasts.

    PubMed

    Dismukes, G C; Sauer, K

    1978-12-01

    The orientation of membrane-bound radicals in spinach chloroplasts is examined by electron paramagnetic resonance (EPR) spectroscopy of chloroplasts oriented by magnetic fields. Several of the membrane-bound radicals which possess g-tensor anisotropy display EPR signals with a marked dependence on the orientation of the membranes relative to the applied EPR field. The fraction of oxidized and reduced plastocyanin, P-700, iron-sulfur proteins A and B, and the X center, an early acceptor of Photosystem I, can be controlled by the light intensity during steady-state illumination and can be trapped by cooling. The X center can be photoreduced and trapped in the absence of strong reductants and high pH, conditions previously found necessary for its detection. These results confirm its role as an early electron acceptor in P-700 photo-oxidation. X is oriented with its smallest principal g-tensor axis (gx) predominantly parallel to the normal to the thylakoid membrane, the same orientation as was found for an early electron acceptor based on time-resolved electron spin polarization studies. We propose that the X center is the first example of a high potential iron-sulfur protein which functions in electron transfer in its 'superreduced' state. We present evidence which suggests that iron-sulfur proteins A and B are 4Fe-4S clusters in an 8Fe-8S protein. Center B is oriented with gy predominantly normal to the membrane plane. The spectra of center A and plastocyanin do not show significant changes with sample orientation. In the case of plastocyanin, this may indicate a lack of molecular orientation. The absence of an orientation effect for reduced center A is reconcilable with a 4Fe-4S geometry, provided that the electron obtained upon reduction can be shared between any pair of Fe atoms in the center. Orientation of the 'Rieske' iron-sulfur protein is also observed. It has axial symmetry with g parallel close to the plane of the membrane. A model is proposed for the

  20. Orienteering for Sport and Pleasure.

    ERIC Educational Resources Information Center

    Bengtsson, Hans; Atkinson, George

    This text presents the principles of the sport of orienteering (navigating through an unknown area using a map and compass as guide) and is useful to beginners, experienced orienteers, and "armchair" orienteers. Included in the text are: (1) a glossary of key words; (2) a basic introduction to, and history of, the sport; (3) description of the…

  1. Magnetically Actuated Propellant Orientation Experiment, Controlling Fluid Motion With Magnetic Fields in a Low-Gravity Environment

    NASA Technical Reports Server (NTRS)

    Martin, J. J.; Holt, J. B.

    2000-01-01

    This report details the results of a series of fluid motion experiments to investigate the use of magnets to orient fluids in a low-gravity environment. The fluid of interest for this project was liquid oxygen (LO2) since it exhibits a paramagnetic behavior (is attracted to magnetic fields). However, due to safety and handling concerns, a water-based ferromagnetic mixture (produced by Ferrofluidics Corporation) was selected to simplify procedures. Three ferromagnetic fluid mixture strengths and a nonmagnetic water baseline were tested using three different initial fluid positions with respect to the magnet. Experiment accelerometer data were used with a modified computational fluid dynamics code termed CFX-4 (by AEA Technologies) to predict fluid motion. These predictions compared favorably with experiment video data, verifying the code's ability to predict fluid motion with and without magnetic influences. Additional predictions were generated for LO2 with the same test conditions and geometries used in the testing. Test hardware consisted of a cylindrical Plexiglas tank (6-in. bore with 10-in. length), a 6,000-G rare Earth magnet (10-in. ring), three-axis accelerometer package, and a video recorder system. All tests were conducted aboard the NASA Reduced-Gravity Workshop, a KC-135A aircraft.

  2. Using an electronic compass to determine telemetry azimuths

    USGS Publications Warehouse

    Cox, R.R.; Scalf, J.D.; Jamison, B.E.; Lutz, R.S.

    2002-01-01

    Researchers typically collect azimuths from known locations to estimate locations of radiomarked animals. Mobile, vehicle-mounted telemetry receiving systems frequently are used to gather azimuth data. Use of mobile systems typically involves estimating the vehicle's orientation to grid north (vehicle azimuth), recording an azimuth to the transmitter relative to the vehicle azimuth from a fixed rosette around the antenna mast (relative azimuth), and subsequently calculating an azimuth to the transmitter (animal azimuth). We incorporated electronic compasses into standard null-peak antenna systems by mounting the compass sensors atop the antenna masts and evaluated the precision of this configuration. This system increased efficiency by eliminating vehicle orientation and calculations to determine animal azimuths and produced estimates of precision (azimuth SD=2.6 deg., SE=0.16 deg.) similar to systems that required orienting the mobile system to grid north. Using an electronic compass increased efficiency without sacrificing precision and should produce more accurate estimates of locations when marked animals are moving or when vehicle orientation is problematic.

  3. Magnetic-field effect on the photoactivation reaction of Escherichia coli DNA photolyase

    PubMed Central

    Henbest, Kevin B.; Maeda, Kiminori; Hore, P. J.; Joshi, Monika; Bacher, Adelbert; Bittl, Robert; Weber, Stefan; Timmel, Christiane R.; Schleicher, Erik

    2008-01-01

    One of the two principal hypotheses put forward to explain the primary magnetoreception event underlying the magnetic compass sense of migratory birds is based on a magnetically sensitive chemical reaction. It has been proposed that a spin-correlated radical pair is produced photochemically in a cryptochrome and that the rates and yields of the subsequent chemical reactions depend on the orientation of the protein in the Earth's magnetic field. The suitability of cryptochrome for this purpose has been argued, in part, by analogy with DNA photolyase, although no effects of applied magnetic fields have yet been reported for any member of the cryptochrome/photolyase family. Here, we demonstrate a magnetic-field effect on the photochemical yield of a flavin–tryptophan radical pair in Escherichia coli photolyase. This result provides a proof of principle that photolyases, and most likely by extension also cryptochromes, have the fundamental properties needed to form the basis of a magnetic compass. PMID:18799743

  4. Magnetic-field effect on the photoactivation reaction of Escherichia coli DNA photolyase.

    PubMed

    Henbest, Kevin B; Maeda, Kiminori; Hore, P J; Joshi, Monika; Bacher, Adelbert; Bittl, Robert; Weber, Stefan; Timmel, Christiane R; Schleicher, Erik

    2008-09-23

    One of the two principal hypotheses put forward to explain the primary magnetoreception event underlying the magnetic compass sense of migratory birds is based on a magnetically sensitive chemical reaction. It has been proposed that a spin-correlated radical pair is produced photochemically in a cryptochrome and that the rates and yields of the subsequent chemical reactions depend on the orientation of the protein in the Earth's magnetic field. The suitability of cryptochrome for this purpose has been argued, in part, by analogy with DNA photolyase, although no effects of applied magnetic fields have yet been reported for any member of the cryptochrome/photolyase family. Here, we demonstrate a magnetic-field effect on the photochemical yield of a flavin-tryptophan radical pair in Escherichia coli photolyase. This result provides a proof of principle that photolyases, and most likely by extension also cryptochromes, have the fundamental properties needed to form the basis of a magnetic compass.

  5. 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.

  6. 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.

  7. 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.

  8. Effects of rolling conditions on grain orientation and magnetic properties of thin-gauged 3% Si-Fe sheets

    SciTech Connect

    Kim, J.C.; Heo, N.H.; Chai, K.H.; Na, J.G.; Woo, J.S.; Kim, G.M.

    1998-04-03

    3% Si-Fe sheets are widely used as core material of large transformers, large rotating machines and pole transformers due to characteristic soft magnetic properties, where energy losses during magnetization are critically concerned. The magnetic characteristics in silicon iron arises from a preferred grain orientation, i.e. (110) [001] Goss texture which forms after cold rolling followed by secondary recrystallization. In this paper, effects of rolling direction on the grain orientation and magnetic properties of the thin-gauged 3% Si-Fe sheets are investigated.

  9. Orientational and magnetic ordering of buckyballs in TDAE-C60

    SciTech Connect

    Mihailovic, D.; Arcon, D.; Venturini, P.; Blinc, R.; Omerzu, A.; Cevc, P.

    1995-04-01

    Spin ordering in the low-temperature magnetic phase is directly linked to the orientational ordering of C60 molecules in organically doped fullerene derivatives. Electron spin resonance and alternating current susceptometry measurements on tetrakis (dimethylamino) ethylene-C60 (TDAE-C60) (Curie temperature T(sub c) = 16 kelvin) show a direct coupling between spin and merohedral degrees of freedom. This coupling was experimentally demonstrated by showing that ordering the spins in the magnetic phase imprints a merohedral order on the solid or, conversely, that merohedrally ordering the C60 molecules influences the spin order at low temperature. The merohedral disorder gives rise to a distribution of pi-electron exchange interactions between spins on neighboring C60 molecules, suggesting a microscopic origin for the observed spin-glass behavior of the magnetic state. 18 refs.

  10. Nucleation controlled magnetization reversal mechanism in oriented L10 FeCoPt ternary alloys

    NASA Astrophysics Data System (ADS)

    Goyal, Rajan; Sehdev, Neeru; Lamba, S.; Annapoorni, S.

    2016-01-01

    The angular dependence of scaled coercivity is investigated within the framework of various theoretical models to gather an insight into the magnetization reversal mechanism in hard magnetic materials. FeCoPt ternary alloy thin films with low concentration of Co were successfully fabricated on an <100> Si substrate with different working pressures in order to attain an optimum energy product. The structural and hysteresis curve analysis show an improvement in atomic ordering and orientation of easy axis with annealing temperature. The experimental data for angular dependence of coercivity along with the theoretical predications based on the nucleation model indicates that the dominant reversal mechanism is nucleation along with a slight contribution from pinning. The magnetic force microscopy (MFM) imaging also supports the above model. The evolution of morphology and microstructure characterized by atomic force microscopy (AFM) was directly linked to an increase in surface roughness.

  11. Synthesis of crystallographically oriented olivine aggregates using colloidal processing in a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Koizumi, Sanae; Suzuki, Tohru S.; Sakka, Yoshio; Yabe, Kosuke; Hiraga, Takehiko

    2016-07-01

    This study develops a fabrication technique to obtain Fe-free and Fe-bearing (Fe:Mg = 1:9) olivine aggregates not only with high density and fine grain size but with crystallographic preferred orientation (CPO). A magnetic field (≤12 T) is applied to synthetic, fine-grained (~120 nm), olivine particles dispersed in solvent. The alignment of certain crystallographic axes of the particles with respect to a magnetic direction is anticipated due to magnetic anisotropy of olivine. The dispersed particles are gradually consolidated on a porous alumina mold covered with a solid-liquid separation filter during drainage of the solvent. The resultant aligned consolidated aggregate is then isostatically pressed and vacuum sintered. We find that (1) preparation of fully reacted olivine particles, with less propensity to coalesce; (2) preparation of a suspension with highly dispersed particles; and (3) application of a certain strength of the magnetic field are essential to obtain well-sintered and well-aligned aggregates. High density (i.e., <1 vol% porosity) and fine grain size (~1 μm) Fe-free and Fe-bearing olivine aggregates were successfully synthesized with uniaxially aligned a- and c-axes, respectively. Attempts to uniaxially align the magnetization hard axis and to triaxially align Fe-bearing olivine by rotating the suspension in the magnetic field succeeded in obtaining weakly developed CPO aggregates.

  12. Signal Transduction Model of Magnetic Sensing in Cryptochrome Mediated Photoreception

    NASA Astrophysics Data System (ADS)

    Todd, Phillise Tiffeny

    While migratory birds have long been known to use the Earth's magnetic field for navigation, the precise biophysical mechanism behind this magnetic sense remains unconfirmed. A leading theory of magnetoreception suggests a chemical compass model with a yet undetermined molecular reaction site and unknown magnetically sensitive reactants. The cryptochrome photoreceptor has emerged as a promising candidate site. This investigation numerically models the first order kinetics of cryptochrome mediated photoreception, in order to evaluate its ability to function as a magnetic sensor and transduce orientation information along a neural pathway. A signal-to-noise ratio is defined to quantify the threshold for the functioning of a cryptochrome-based chemical compass. The model suggests that a flavin-superoxide radical pair in cryptochrome functions as the chemical reactants for magnetoreception. Such a cryptochrome-based signal transduction model reasonably predicts the general light intensity and wavelength effects that have been experimentally observed in migratory birds.

  13. Organization dependent collective magnetic properties of secondary nanostructures with differential spatial ordering and magnetic easy axis orientation

    NASA Astrophysics Data System (ADS)

    Saikia, K.; Sarma, D. D.; Deb, P.

    2016-06-01

    Achieving control on the formation of different organization states of magnetic nanoparticles is crucial to harness their organization dependent physical properties in desired ways. In this study, three organization states of iron oxide nanoparticles (γ-Fe2O3), defining as (i) assembly (ii) network aggregate and (iii) cluster, have been developed by simply changing the solvent evaporation conditions. All three systems have retained the same phase and polydispersity of primary particles. Magnetic measurements show that the partial alignment of the easy axes of the particles in the network system due to the stacking aggregation morphology can result in significant enhancement of the coercivity and remanence values, while the opposite is obtained for the cluster system due to the random orientation of easy axes. Partial alignment in the aggregate system also results in noticeable non-monotonic field dependence of ZFC peak temperature (Tpeak). The lowest value of the blocking temperature (TB) for the cluster system is related to the lowering of the effective anisotropy due to the strongest demagnetizing effect. FC (Field cooled) memory effect was observed to be decreasing with the increasing strength of dipolar interaction of organization states. Therefore, the stacking aggregation and the cluster formation are two interesting ways of magnetic nanoparticles organization for modulating collective magnetic properties significantly, which can have renewed application potentials from recording devices to biomedicine.

  14. Quaternion-based extended Kalman filter for determining orientation by inertial and magnetic sensing.

    PubMed

    Sabatini, Angelo M

    2006-07-01

    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 movement. In the proposed EKF, the quaternion associated with the body rotation is included in the state vector together with the bias of the aiding system sensors. Moreover, in addition to the in-line procedure of sensor bias compensation, the measurement noise covariance matrix is adapted, to guard against the effects which body motion and temporary magnetic disturbance may have on the reliability of measurements of gravity and earth's magnetic field, respectively. By computer simulations and experimental validation with human hand orientation motion signals, improvements in the accuracy of orientation estimates are demonstrated for the proposed EKF, as compared with filter implementations where either the in-line calibration procedure, the adaptive mechanism for weighting the measurements of the aiding system sensors, or both are not implemented. PMID:16830938

  15. An object-oriented framework for magnetic-fusion modeling and analysis codes

    SciTech Connect

    Cohen, R H; Yang, T Y Brian

    1999-03-04

    The magnetic-fusion energy (MFE) program, like many other scientific and engineering activities, has a need to efficiently develop complex modeling codes which combine detailed models of components to make an integrated model of a device, as well as a rich supply of legacy code that could provide the component models. There is also growing recognition in many technical fields of the desirability of steerable software: computer programs whose functionality can be changed by the user as it is run. This project had as its goals the development of two key pieces of infrastructure that are needed to combine existing code modules, written mainly in Fortran, into flexible, steerable, object-oriented integrated modeling codes for magnetic- fusion applications. These two pieces are (1) a set of tools to facilitate the interfacing of Fortran code with a steerable object-oriented framework (which we have chosen to be based on PythonlW3, an object-oriented interpreted language), and (2) a skeleton for the integrated modeling code which defines the relationships between the modules. The first of these activities obviously has immediate applicability to a spectrum of projects; the second is more focussed on the MFE application, but may be of value as an example for other applications.

  16. Quaternion-based extended Kalman filter for determining orientation by inertial and magnetic sensing.

    PubMed

    Sabatini, Angelo M

    2006-07-01

    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 movement. In the proposed EKF, the quaternion associated with the body rotation is included in the state vector together with the bias of the aiding system sensors. Moreover, in addition to the in-line procedure of sensor bias compensation, the measurement noise covariance matrix is adapted, to guard against the effects which body motion and temporary magnetic disturbance may have on the reliability of measurements of gravity and earth's magnetic field, respectively. By computer simulations and experimental validation with human hand orientation motion signals, improvements in the accuracy of orientation estimates are demonstrated for the proposed EKF, as compared with filter implementations where either the in-line calibration procedure, the adaptive mechanism for weighting the measurements of the aiding system sensors, or both are not implemented.

  17. In Search of Compassion: A New Taxonomy of Compassionate Physician Behaviors

    PubMed Central

    Cameron, Rachel A.; Mazer, Benjamin L.; DeLuca, Jane M.; Mohile, Supriya G.; Epstein, Ronald M.

    2014-01-01

    Background Compassion has been extolled as a virtue in the physician-patient relationship as a response to patient suffering. However, there are few studies that systematically document the behavioral features of physician compassion and the ways in which physicians communicate compassion to patients. Objective To develop a taxonomy of compassionate behaviors and statements expressed by the physician that can be discerned by an outside observer. Design Qualitative analysis of audio-recorded office visits between oncologists and patients with advanced cancer. Setting and Participants Oncologists (n=23) and their patients with advanced cancer (n=49) were recruited in the greater Rochester, New York, area. The physicians and patients were surveyed and had office visits audio-recorded. Main Outcome Measures Audio-recordings were listened to for qualitative assessment of communication skills. Results Our sensitizing framework was oriented around three elements of compassion: recognition of the patient’s suffering, emotional resonance, and movement towards addressing suffering. Statements of compassion included direct statements, paralinguistic expressions, and performative comments. Compassion frequently unfolded over the course of a conversation rather than being a single discrete event. Additionally, non-verbal linguistic elements (e.g. silence) were frequently employed to communicate emotional resonance. Discussion and Conclusions This study is the first to systematically catalog instances of compassionate communication in physician-patient dialogues. Further refinement and validation of this preliminary taxonomy can guide future education and training interventions to facilitate compassion in physician-patient interactions. PMID:24305037

  18. 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

  19. Compassion, compassion fatigue, and burnout: key insights for oncology professionals.

    PubMed

    Back, Anthony L; Deignan, Paul F; Potter, Patricia A

    2014-01-01

    When cancer care clinicians become stressed, sad, isolated--and unaware of this--they are placing themselves at risk for burnout and their patients at risk for suboptimal care. Despite their best intentions, clinicians can sink from a healthy work state of compassion, empathy, and well-being into compassion fatigue and burnout. Lessons from first responders demonstrate the importance for clinicians to recognize the warning signs of compassion and fatigue and burnout, as this recognition can enable them to take action towards prevention and/or recovery. The recognition of these issues as a threat to clinician performance has outstripped the development of evidence-based interventions, but interventions tested to date are effective, feasible, and scalable. These interventions could be incorporated systematically into cancer care.

  20. Generation of an external magnetic field with the spin orientation effect in a single layer Ising nanographene

    NASA Astrophysics Data System (ADS)

    Şarlı, Numan

    2016-09-01

    In this work, the magnetic properties of the single layer Ising nanogaphene (SLING) are investigated by using Kaneyoshi approach (KA) within the effective field theory for different spin orientations of its magnetic atoms. We find that the magnetizations of the SLING has no phase transition, certain Curie temperature and distinct peak of susceptibility at Tc for the some spin orientations at the zero external magnetic field (H=0.0). Because these behaviors occur at H≠0.0, we suggest that the SLING generates an external magnetic field and behaves as an external magnetic field generator for these spin orientations. However, the SLING exhibits ferromagnetic behaviors for only one spin orientations. But, it exhibits antiferromagnetic behaviors for the others. For the AFM cases, diamagnetic susceptibility behaviors and type II superconductivity hysteresis behaviors are obtained. We hope that these results can open a door to obtain new class of single layer graphene and graphene-based magnetic field generator devices with the spin orientation effect.

  1. 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.

  2. 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

  3. Control of proliferation rate of N27 dopaminergic neurons using Transcranial Magnetic Stimulation orientation

    NASA Astrophysics Data System (ADS)

    Meng, Yiwen; Hadimani, Ravi; Anantharam, Vellareddy; Kanthasamy, Anumantha; Jiles, David

    2015-03-01

    Transcranial magnetic stimulation (TMS) has been used to investigate possible treatments for a variety of neurological disorders. However, the effect that magnetic fields have on neurons has not been well documented in the literature. We have investigated the effect of different orientation of magnetic field generated by TMS coils with a monophasic stimulator on the proliferation rate of N27 neuronal cells cultured in flasks and multi-well plates. The proliferation rate of neurons would increase by exposed horizontally adherent N27 cells to a magnetic field pointing upward through the neuronal proliferation layer compared with the control group. On the other hand, proliferation rate would decrease in cells exposed to a magnetic field pointing downward through the neuronal growth layer compared with the control group. We confirmed results obtained from the Trypan-blue and automatic cell counting methods with those from the CyQuant and MTS cell viability assays. Our findings could have important implications for the preclinical development of TMS treatments of neurological disorders and represents a new method to control the proliferation rate of neuronal cells.

  4. Rydberg states of helium in electric and magnetic fields of arbitrary relative orientation

    NASA Astrophysics Data System (ADS)

    Tkáč, Ondřej; Žeško, Matija; Agner, Josef A.; Schmutz, Hansjürg; Merkt, Frédéric

    2016-05-01

    A spectroscopic study of Rydberg states of helium (n = 30 and 45) in magnetic, electric and combined magnetic and electric fields with arbitrary relative orientations of the field vectors is presented. The emphasis is on two special cases where (i) the diamagnetic term is negligible and both paramagnetic Zeeman and Stark effects are linear (n = 30, B ≤ 120 mT and F = 0–78 V cm‑1), and (ii) the diamagnetic term is dominant and the Stark effect is linear (n = 45, B = 277 mT and F = 0–8 V cm‑1). Both cases correspond to regimes where the interactions induced by the electric and magnetic fields are much weaker than the Coulomb interaction, but much stronger than the spin–orbit interaction. The experimental spectra are compared to spectra calculated by determining the eigenvalues of the Hamiltonian matrix describing helium Rydberg states in the external fields. The spectra and the calculated energy-level diagrams in external fields reveal avoided crossings between levels of different m l values and pronounced m l -mixing effects at all angles between the electric- and magnetic-field vectors other than 0. These observations are discussed in the context of the development of a method to generate dense samples of cold atoms and molecules in a magnetic trap following Rydberg–Stark deceleration.

  5. 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

  6. Rydberg states of helium in electric and magnetic fields of arbitrary relative orientation

    NASA Astrophysics Data System (ADS)

    Tkáč, Ondřej; Žeško, Matija; Agner, Josef A.; Schmutz, Hansjürg; Merkt, Frédéric

    2016-05-01

    A spectroscopic study of Rydberg states of helium (n = 30 and 45) in magnetic, electric and combined magnetic and electric fields with arbitrary relative orientations of the field vectors is presented. The emphasis is on two special cases where (i) the diamagnetic term is negligible and both paramagnetic Zeeman and Stark effects are linear (n = 30, B ≤ 120 mT and F = 0-78 V cm-1), and (ii) the diamagnetic term is dominant and the Stark effect is linear (n = 45, B = 277 mT and F = 0-8 V cm-1). Both cases correspond to regimes where the interactions induced by the electric and magnetic fields are much weaker than the Coulomb interaction, but much stronger than the spin-orbit interaction. The experimental spectra are compared to spectra calculated by determining the eigenvalues of the Hamiltonian matrix describing helium Rydberg states in the external fields. The spectra and the calculated energy-level diagrams in external fields reveal avoided crossings between levels of different m l values and pronounced m l -mixing effects at all angles between the electric- and magnetic-field vectors other than 0. These observations are discussed in the context of the development of a method to generate dense samples of cold atoms and molecules in a magnetic trap following Rydberg-Stark deceleration.

  7. Preferred mineral orientation of a chloritoid-bearing slate in relation to its magnetic fabric

    NASA Astrophysics Data System (ADS)

    Haerinck, Tom; Wenk, Hans-Rudolf; Debacker, Timothy N.; Sintubin, Manuel

    2015-02-01

    A regional analysis of the anisotropy of the magnetic susceptibility on low-grade metamorphic, chloritoid-bearing slates of the Paleozoic in Central Armorica (Brittany, France) revealed very high values for the degree of anisotropy (up to 1.43). Nonetheless, high-field torque magnetometry indicates that the magnetic fabric is dominantly paramagnetic. Chloritoid's intrinsic degree of anisotropy of 1.47 ± 0.06, suggests that chloritoid-bearing slates can have a high degree of anisotropy without the need of invoking a significant contribution of strongly anisotropic ferromagnetic (s.l.) minerals. To validate this assumption we performed a texture analysis on a representative sample of the chloritoid-bearing slates using hard X-ray synchrotron diffraction. The preferred orientation patterns of both muscovite and chloritoid are extremely strong (∼38.6 m.r.d. for muscovite, 20.9 m.r.d. for chloritoid) and display roughly axial symmetry about the minimum magnetic susceptibility axis, indeed suggesting that chloritoid may have a profound impact on the magnetic fabric of chloritoid-bearing rocks. However, modeling the anisotropy of magnetic susceptibility by averaging single crystal properties indicates that the CPO of chloritoid only partially explains the slate's anisotropy.

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

    NASA Astrophysics Data System (ADS)

    Homberg, Uwe

    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 act as internal navigation centers. Here I review the significance, peripheral mechanisms, and central processing stages for polarization vision in insects with special reference to the locust Schistocerca gregaria. As in other insect species, polarization vision in locusts relies on specialized photoreceptor cells in a small dorsal rim area of the compound eye. Stages in the brain involved in polarized light signaling include specific areas in the lamina, medulla and lobula of the optic lobe and, in the midbrain, the anterior optic tubercle, the lateral accessory lobe, and the central complex. Integration of polarized-light signals with information on solar position appears to start in the optic lobe. In the central complex, polarization-opponent interneurons form a network of interconnected neurons. The organization of the central complex, its connections to thoracic motor centers, and its involvement in the spatial control of locomotion strongly suggest that it serves as a spatial organizer within the insect brain, including the functions of compass orientation and path integration. Time compensation in compass orientation is possibly achieved through a neural pathway from the internal circadian clock in the accessory medulla to the protocerebral bridge of the central complex.

  9. Rousseau and the Education of Compassion

    ERIC Educational Resources Information Center

    White, Richard

    2008-01-01

    In this paper I examine Rousseau's strategy for teaching compassion in "Book Four of Emile." In particular, I look at the three maxims on compassion that help to organise Rousseau's discussion, and the precise strategy that Emile's tutor uses to instil compassion while avoiding other passions, such as anger, fear and pride. The very idea of an…

  10. Compassion: An Evolutionary Analysis and Empirical Review

    ERIC Educational Resources Information Center

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

    2010-01-01

    What is compassion? And how did it evolve? In this review, we integrate 3 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…

  11. 46 CFR 169.709 - Compass.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Compass. 169.709 Section 169.709 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Vessel Control... compass. (b) Each vessel certificated for exposed water service must have an emergency compass in...

  12. 46 CFR 169.709 - Compass.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Compass. 169.709 Section 169.709 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Vessel Control... compass. (b) Each vessel certificated for exposed water service must have an emergency compass in...

  13. 46 CFR 169.709 - Compass.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Compass. 169.709 Section 169.709 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Vessel Control... compass. (b) Each vessel certificated for exposed water service must have an emergency compass in...

  14. 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…

  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. Effect of metallurgical factors on the bulk magnetic properties of non-oriented electrical steels

    NASA Astrophysics Data System (ADS)

    Ghosh, Pampa; Chromik, Richard R.; Knight, Andrew M.; Wakade, Shekhar G.

    2014-04-01

    Non-oriented electrical steel (NOES) is one of the most common material used in electrical motors. Core loss and permeability are the most important properties that the motor manufacturers look for. Both these properties are structure sensitive and depend on several metallurgical factors; such as chemistry, grain size, crystallographic texture, cleanliness and stress states in non-oriented electrical steels. It has been observed in this course of the study that the grain size and Si content of NOES are the primary controlling factors to core loss, especially at higher frequencies. On the contrary, crystallographic texture plays an important role at lower frequencies. At higher frequency, core loss increases with increasing grain size and decreasing Si content of the steels. Small difference in grain size (~50 μm) at lower frequency range has little influence on the magnetic properties but has significant adverse effect as frequency reaches high enough.

  17. Orientation and autumn migration routes of juvenile sharp-tailed sandpipers at a staging site in Alaska.

    PubMed

    Grönroos, Johanna; Muheim, Rachel; Akesson, Susanne

    2010-06-01

    Arctic waders are well known for their impressive long-distance migrations between their high northerly breeding grounds and wintering areas in the Southern hemisphere. Performing such long migrations requires precise orientation mechanisms. We conducted orientation cage experiments with juvenile sharp-tailed sandpipers (Calidris acuminata) to investigate what cues they rely on when departing from Alaska on their long autumn migration flights across the Pacific Ocean to Australasia, and which possible migration routes they could use. Experiments were performed under natural clear skies, total overcast conditions and in manipulated magnetic fields at a staging site in Alaska. Under clear skies the juvenile sharp-tailed sandpipers oriented towards SSE, which coincides well with reported sun compass directions from their breeding grounds in Siberia towards Alaska and could reflect their true migratory direction towards Australasia assuming that they change direction towards SW somewhere along the route. Under overcast skies the sandpipers showed a mean direction towards SW which would lead them to Australasia, if they followed a sun compass route. However, because of unfavourable weather conditions (headwinds) associated with overcast conditions, these south-westerly directions could also reflect local movements. The juvenile sharp-tailed sandpipers responded clearly to the manipulated magnetic field under overcast skies, suggesting the use of a magnetic compass for selecting their courses.

  18. Orientation and autumn migration routes of juvenile sharp-tailed sandpipers at a staging site in Alaska.

    PubMed

    Grönroos, Johanna; Muheim, Rachel; Akesson, Susanne

    2010-06-01

    Arctic waders are well known for their impressive long-distance migrations between their high northerly breeding grounds and wintering areas in the Southern hemisphere. Performing such long migrations requires precise orientation mechanisms. We conducted orientation cage experiments with juvenile sharp-tailed sandpipers (Calidris acuminata) to investigate what cues they rely on when departing from Alaska on their long autumn migration flights across the Pacific Ocean to Australasia, and which possible migration routes they could use. Experiments were performed under natural clear skies, total overcast conditions and in manipulated magnetic fields at a staging site in Alaska. Under clear skies the juvenile sharp-tailed sandpipers oriented towards SSE, which coincides well with reported sun compass directions from their breeding grounds in Siberia towards Alaska and could reflect their true migratory direction towards Australasia assuming that they change direction towards SW somewhere along the route. Under overcast skies the sandpipers showed a mean direction towards SW which would lead them to Australasia, if they followed a sun compass route. However, because of unfavourable weather conditions (headwinds) associated with overcast conditions, these south-westerly directions could also reflect local movements. The juvenile sharp-tailed sandpipers responded clearly to the manipulated magnetic field under overcast skies, suggesting the use of a magnetic compass for selecting their courses. PMID:20472769

  19. Nucleon spin structure studies at COMPASS

    SciTech Connect

    Marchand, Claude

    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.

  20. The compass within

    PubMed Central

    Schultheiss, Nathan W; Redish, A David

    2016-01-01

    Head direction cells have been hypothesized to form representations of an animal’s spatial orientation through internal network interactions. New data from mice show the predicted signatures of these internal dynamics. PMID:25811477

  1. On the absence of plasma wave emissions and the magnetic field orientation in the distant magnetosheath

    NASA Technical Reports Server (NTRS)

    Coroniti, F. V.; Greenstadt, E. W.; Moses, S. L.; Tsurutani, B. T.; Smith, E. J.

    1994-01-01

    In early September, 1983 ISEE-3 made a long traversal of the distant dawnside magnetosheath starting near x = -150 R(sub E) downstream. The distant magnetosheath often contains moderately intense plasma wave emissions at frequencies from several hundred Hz to 5 kHz. However, over time scales of many days, a clear correlation exists between the occurrence of the plasma waves and the cone angle (theta(sub xB)) between the magnetic field and the plasma flow velocity (x-direction). For theta(sub xB) large (small), the plasma wave amplitudes are near background (high). Sudden (less than 1 minute) changes in the local magnetic field orientation produce correspondingly sudden changes in the wave amplitudes. Statistically, the wave amplitudes decrease continuously with increasing theta(sub xB).

  2. EFFECTS OF MAGNETIC FIELD STRENGTH AND ORIENTATION ON MOLECULAR CLOUD FORMATION

    SciTech Connect

    Heitsch, Fabian; Hartmann, Lee W.; Stone, James M.

    2009-04-10

    We present a set of numerical simulations addressing the effects of magnetic field strength and orientation on the flow-driven formation of molecular clouds. Fields perpendicular to the flows sweeping up the cloud can efficiently prevent the formation of massive clouds but permit the buildup of cold, diffuse filaments. Fields aligned with the flows lead to substantial clouds, whose degree of fragmentation and turbulence strongly depends on the background field strength. Adding a random field component leads to a 'selection effect' for molecular cloud formation: high column densities are only reached at locations where the field component perpendicular to the flows is vanishing. Searching for signatures of colliding flows should focus on the diffuse, warm gas, since the cold gas phase making up the cloud will have lost the information about the original flow direction because the magnetic fields redistribute the kinetic energy of the inflows.

  3. Comparison of lattice preferred orientation and magnetic fabric of a chloritoid-bearing slate

    NASA Astrophysics Data System (ADS)

    Haerinck, Tom; Wenk, Hans-Rudolf; Debacker, Timothy N.; Sintubin, Manuel

    2014-05-01

    contribution of strongly anisotropic ferromagnetic (s.l.)minerals. To validate this assumption a texture analysis has been performed on a representative sample of the chloritoid-bearing slates (PJ = 1.40), using hard X-ray synchrotron diffraction (e.g. Wenk et al. 2010). For estimation of the mineralogical composition and the preferred orientation a Rietveld refinement of the synchrotron X-ray diffraction images has been performed. The Rietveld refinement confirms that the slate contains a significant fraction of chloritoid (21 vol%). The resulting orientation distribution of both muscovite and chloritoid display an approximate axial symmetric (001) pole figure pattern with respect to the minimum magnetic susceptibility axis K3, that has an extremely strong preferred orientation (~36 m.r.d. for muscovite and ~19 m.r.d. for chloritoid). It is therefore fair to conclude that the strong preferred orientation of the chloritoid basal planes parallel to the magnetic fabric, in combination with the pronounced magnetocrystalline anisotropy of chloritoid, explains the very high values for the degree of magnetic anisotropy (PJ) observed in the chloritoid-bearing slates. References Haerinck et al. 2013a. Journal of the Geological Society, London 170, 263-280, doi:10.1144/jgs2012-062. Haerinck et al. 2013b. Journal of Geophysical Research: Solid Earth 118(8), 3886-3898, doi:10.1002/jgrb.50276. Wenk et al. 2010. Journal of Structural Geology 32(4), 478-489, doi:10.1016/j.jsg.2010.02.003.

  4. 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

  5. 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.

  6. 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

  7. 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

  8. Structural and magnetic properties of (111) oriented annealed ultrathin Co/Pt multilayers

    NASA Astrophysics Data System (ADS)

    Sharma, A.; Tripathi, S.; Tripathi, J.

    2016-05-01

    The effect of annealing on the structural and magnetic properties of Co/Pt multilayers was studied as a function of annealing temperature. The ultrathin layers of Pt and Co were deposited to make [Pt 1nm/Co 1nm]x20 multilayer on Si (100) substrate using MBE technique. The structural, magnetic and electronic properties were recorded using XRD, SQUID and XPS techniques, respectively. M-H loop of as deposited sample shows soft magnetic nature with coercivity value of 350 Oe which increases to 974 Oe in 500°C annealed film. When studied at low temperature (5K), the coercivity of 592 Oe is obtained in the as deposited sample which increases to 1626 Oe after annealing. In addition, as revealed by X-ray photoelectron spectroscopy, modifications in core level and valance band are observed. The observed changes in magnetic and electronic properties are attributed to structural modifications in correlation with the changes in (111) orientation of the films seen by X-ray diffraction.

  9. 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

  10. 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 Central

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

    2014-01-01

    Abstract 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. Key Words: Levitation—Microgravity—Gravitaxis—Gravikinesis—Gravity. Astrobiology 14, 205–215. PMID:24621307

  11. 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.

  12. Optical orientation of hole magnetic polarons in (Cd,Mn)Te/(Cd,Mn,Mg)Te quantum wells

    NASA Astrophysics Data System (ADS)

    Zhukov, E. A.; Kusrayev, Yu. G.; Kavokin, K. V.; Yakovlev, D. R.; Debus, J.; Schwan, A.; Akimov, I. A.; Karczewski, G.; Wojtowicz, T.; Kossut, J.; Bayer, M.

    2016-06-01

    The optically induced spin polarization in (Cd,Mn)Te/(Cd,Mn,Mg)Te diluted-magnetic-semiconductor quantum wells is investigated by means of picosecond pump-probe Kerr rotation. At 1.8 K temperature, additionally to the oscillatory signals from photoexcited electrons and manganese spins precessing about an external magnetic field, a surprisingly long-lived (up to 60 ns) nonoscillating spin polarization is detected. This polarization is related to optical orientation of equilibrium magnetic polarons involving resident holes. The suggested mechanism for the optical orientation of the equilibrium magnetic polarons indicates that the detected polaron dynamics originates from unexcited magnetic polarons. The polaron spin dynamics is controlled by the anisotropic spin structure of the heavy hole resulting in a freezing of the polaron magnetic moment in one of the two stable states oriented along the structure growth axis. Spin relaxation between these states is prohibited by a potential barrier, which depends on temperature and magnetic field. The magnetic polaron relaxation is accelerated with increasing temperature and in magnetic field.

  13. Magnetic-field-induced orientational order in the isotropic phase of hard colloidal platelets

    SciTech Connect

    Beek, D. van der; Petukhov, A.V.; Vroege, G.J.; Lekkerkerker, H.N.W.; Davidson, P.; Ferre, J.; Jamet, J.P.; Wensink, H.H.; Bras, W.

    2006-04-15

    The magnetic-field-induced orientational order in the isotropic phase of colloidal gibbsite [Al(OH){sub 3}] platelets is studied by means of optical birefringence and small-angle x-ray scattering (SAXS) techniques. The suspensions display field-induced ordering at moderate field strengths (a few Tesla), which increases with increasing particle concentration. The gibbsite particles align their normals perpendicular to the magnetic field and hence possess a negative anisotropy of their diamagnetic susceptibility {delta}{chi}. The results can be described following a simple, Onsager-like approach. A simplified model is derived that allows one to obtain the orientational distribution function directly from the scattering data. However, it leads to an underestimate of the diamagnetic susceptibility anisotropy {delta}{chi}. This accounts for the difference between the {delta}{chi} values provided by the two experimental techniques (SAXS and magneto-optics). The order of magnitude {delta}{chi}{approx}10{sup -22} J/T{sup 2} lies in between that of goethite suspensions and that of suspensions of organic particles.

  14. Auditory orienting and inhibition of return in schizophrenia: A functional magnetic resonance imaging study

    PubMed Central

    Abbott, Christopher C.; Merideth, Flannery; Ruhl, David; Yang, Zhen; Clark, Vincent P.; Calhoun, Vince D.; Hanlon, Faith M.; Mayer, Andrew R.

    2011-01-01

    Patients with schizophrenia (SP) exhibit deficits in both attentional reorienting and inhibition of return (IOR) during visual tasks. However, it is currently unknown whether these deficits are supramodal in nature and how these deficits relate to other domains of cognitive dysfunction. In addition, the neuronal correlates of this pathological orienting response have not been investigated in either the visual or auditory modality. Therefore, thirty SP and 30 healthy controls (HC) were evaluated with an extensive clinical protocol and functional magnetic resonance imaging (fMRI) during an auditory cuing paradigm. SP exhibited both increased costs and delayed IOR during auditory orienting, suggesting a prolonged interval for attentional disengagement from cued locations. Moreover, a delay in the development of IOR was associated with cognitive deficits on formal neuropsychological testing in the domains of attention/inhibition and working memory. Event-related fMRI showed the characteristic activation of a frontoparietal network (invalid trials > valid trials), but there were no differences in functional activation between patients and HC during either attentional reorienting or IOR. Current results suggest that orienting deficits are supramodal in nature in SP, and are related to higher-order cognitive deficits that directly interfere with day-to-day functioning. PMID:22230646

  15. The COMPASS Polarized Target in 2006 and 2007

    SciTech Connect

    Doshita, N.; Iwata, T.; Kondo, K.; Michigami, T.; Ball, J.; Magnon, A.; Marchand, C.; Baum, G.; Gautheron, F.; Goertz, St.; Hasegawa, T.; Matsuda, T.; Heckmann, J.; Hess, Ch.; Kisselev, Y.; Koivuniemi, J.; Meyer, W.; Radtke, E.; Reicherz, G.; Horikawa, N.

    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.

  16. Magnetic susceptibility anisotropy: cylindrical symmetry from macroscopically ordered anisotropic molecules and accuracy of MRI measurements using few orientations.

    PubMed

    Wisnieff, Cynthia; Liu, Tian; Spincemaille, Pascal; Wang, Shuai; Zhou, Dong; Wang, Yi

    2013-04-15

    White matter is an essential component of the central nervous system and is of major concern in neurodegenerative diseases such as multiple sclerosis (MS). Recent MRI studies have explored the unique anisotropic magnetic properties of white matter using susceptibility tensor imaging. However, these measurements are inhibited in practice by the large number of different head orientations needed to accurately reconstruct the susceptibility tensor. Adding reasonable constraints reduces the number of model parameters and can help condition the tensor reconstruction from a small number of orientations. The macroscopic magnetic susceptibility is decomposed as a sum of molecular magnetic polarizabilities, demonstrating that macroscopic order in molecular arrangement is essential to the existence of and symmetry in susceptibility anisotropy and cylindrical symmetry is a natural outcome of an ordered molecular arrangement. Noise propagation in the susceptibility tensor reconstruction is analyzed through its condition number, showing that the tensor reconstruction is highly susceptible to the distribution of acquired subject orientations and to the tensor symmetry properties, with a substantial over- or under-estimation of susceptibility anisotropy in fiber directions not favorably oriented with respect to the acquired orientations. It was found that a careful acquisition of three non-coplanar orientations and the use of cylindrical symmetry guided by diffusion tensor imaging allowed reasonable estimation of magnetic susceptibility anisotropy in certain major white matter tracts in the human brain. PMID:23296181

  17. Magnetic cylindrical colloids at liquid interfaces exhibit non-volatile switching of their orientation in an external field.

    PubMed

    Newton, Bethany J; Buzza, D Martin A

    2016-06-28

    We study the orientation of magnetic cylindrical particles adsorbed at a liquid interface in an external field using analytical theory and high resolution finite element simulations. Cylindrical particles are interesting since they possess multiple locally stable orientations at the liquid interface so that the orientational transitions induced by an external field will not disappear when the external field is removed, i.e., the switching effect is non-volatile. We show that, in the absence of an external field, as we reduce the aspect ratio α of the cylinders below a critical value (αc≈ 2) the particles undergo spontaneous symmetry breaking from a stable side-on state to one of two equivalent stable tilted states, similar to the spontaneous magnetisation of a ferromagnet going through the Curie point. By tuning both the aspect ratio and contact angle of the cylinders, we show that it is possible to engineer particles that have one, two, three or four locally stable orientations. We also find that the magnetic responses of cylinders with one or two stable states are similar to that of paramagnets and ferromagnets respectively, while the magnetic response of systems with three or four stable states are even more complex and have no analogs in simple magnetic systems. Magnetic cylinders at liquid interfaces therefore provide a facile method for creating switchable functional monolayers where we can use an external field to induce multiple non-volatile changes in particle orientation and self-assembled structure. PMID:27200513

  18. Magnetic cylindrical colloids at liquid interfaces exhibit non-volatile switching of their orientation in an external field.

    PubMed

    Newton, Bethany J; Buzza, D Martin A

    2016-06-28

    We study the orientation of magnetic cylindrical particles adsorbed at a liquid interface in an external field using analytical theory and high resolution finite element simulations. Cylindrical particles are interesting since they possess multiple locally stable orientations at the liquid interface so that the orientational transitions induced by an external field will not disappear when the external field is removed, i.e., the switching effect is non-volatile. We show that, in the absence of an external field, as we reduce the aspect ratio α of the cylinders below a critical value (αc≈ 2) the particles undergo spontaneous symmetry breaking from a stable side-on state to one of two equivalent stable tilted states, similar to the spontaneous magnetisation of a ferromagnet going through the Curie point. By tuning both the aspect ratio and contact angle of the cylinders, we show that it is possible to engineer particles that have one, two, three or four locally stable orientations. We also find that the magnetic responses of cylinders with one or two stable states are similar to that of paramagnets and ferromagnets respectively, while the magnetic response of systems with three or four stable states are even more complex and have no analogs in simple magnetic systems. Magnetic cylinders at liquid interfaces therefore provide a facile method for creating switchable functional monolayers where we can use an external field to induce multiple non-volatile changes in particle orientation and self-assembled structure.

  19. The Structure and Development of Dispositional Compassion in Early Adolescence

    ERIC Educational Resources Information Center

    Bengtsson, Hans; Söderström, Micael; Terjestam, Yvonne

    2016-01-01

    Compassion may be directed at a broad range of targets. The present study investigated interrelations among other-directed compassion, self-compassion, and environmental compassion in early adolescence (age = 12-14; n = 256) and examined how the different manifestations of compassion related to age and sex during this age period. Dispositional…

  20. 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.

  1. (110) Orientation growth of magnetic metal nanowires with face-centered cubic structure using template synthesis technique

    SciTech Connect

    Wang Xuewei; Yuan Zhihao; Li Jushan

    2011-06-15

    A template-assisted assembly technique has been used to synthesize magnetic metal nanowire arrays. Fe, Co, Ni nanowires are fabricated using direct-current electrodeposition in the pores of anodic alumina membranes. The morphology and the crystal structure of the samples are characterized by field-emission scanning electron microscopy, transmission electron microscopy, and X-ray diffractometer. The results indicate that Fe, Co, and Ni nanowires all have face-centered cubic (FCC) structure and a preferred orientation along the [110] direction. The ability to prepare well-defined orientation growth of magnetic metal nanowires with FCC structure opens up new opportunities for both fundamental studies and nanodevice applications. - Research Highlights: {yields} Fe, Co, and Ni nanowires are fabricated in the AAM templates by electrodeposition. {yields} Well-defined orientation growth of the nanowires with FCC structure were investigated. {yields} The electrodeposition parameters affect the crystal structure and growth orientation.

  2. A functional role of the sky's polarization pattern for orientation in the greater mouse-eared bat.

    PubMed

    Greif, Stefan; Borissov, Ivailo; Yovel, Yossi; Holland, Richard A

    2014-07-22

    Animals can call on a multitude of sensory information to orient and navigate. One such cue is the pattern of polarized light in the sky, which for example can be used by birds as a geographical reference to calibrate other cues in the compass mechanism. Here we demonstrate that the female greater mouse-eared bat (Myotis myotis) uses polarization cues at sunset to calibrate a magnetic compass, which is subsequently used for orientation during a homing experiment. This renders bats the only mammal known so far to make use of the polarization pattern in the sky. Although there is currently no clear understanding of how this cue is perceived in this taxon, our observation has general implications for the sensory biology of mammalian vision.

  3. A functional role of the sky's polarization pattern for orientation in the greater mouse-eared bat.

    PubMed

    Greif, Stefan; Borissov, Ivailo; Yovel, Yossi; Holland, Richard A

    2014-01-01

    Animals can call on a multitude of sensory information to orient and navigate. One such cue is the pattern of polarized light in the sky, which for example can be used by birds as a geographical reference to calibrate other cues in the compass mechanism. Here we demonstrate that the female greater mouse-eared bat (Myotis myotis) uses polarization cues at sunset to calibrate a magnetic compass, which is subsequently used for orientation during a homing experiment. This renders bats the only mammal known so far to make use of the polarization pattern in the sky. Although there is currently no clear understanding of how this cue is perceived in this taxon, our observation has general implications for the sensory biology of mammalian vision. PMID:25050897

  4. A functional role of the sky’s polarization pattern for orientation in the greater mouse-eared bat

    PubMed Central

    Greif, Stefan; Borissov, Ivailo; Yovel, Yossi; Holland, Richard A.

    2014-01-01

    Animals can call on a multitude of sensory information to orient and navigate. One such cue is the pattern of polarized light in the sky, which for example can be used by birds as a geographical reference to calibrate other cues in the compass mechanism. Here we demonstrate that the female greater mouse-eared bat (Myotis myotis) uses polarization cues at sunset to calibrate a magnetic compass, which is subsequently used for orientation during a homing experiment. This renders bats the only mammal known so far to make use of the polarization pattern in the sky. Although there is currently no clear understanding of how this cue is perceived in this taxon, our observation has general implications for the sensory biology of mammalian vision. PMID:25050897

  5. Orientation of lamellar phases of lyotropic multicomponent mixtures, based on cetyltrimethylammonium bromide cationic detergent, in magnetic field

    NASA Astrophysics Data System (ADS)

    Kiirend, E. O.; Chumakova, S. P.; Pekhk, T. I.; Ivanov, N. R.

    2013-11-01

    The orientation of the lamellar phases in lyotropic systems based on cetyltrimethylammonium bromide (CTAB) detergent has been studied by polarization optical microscopy and 2H-NMR methods. The lamellar lyotropics studied are shown to align under a strong magnetic field of 11.7 T. According to 2H-NMR data, structural transformations of the lamellar phases may occur during orientation when the sample temperature increases.

  6. Attachment and mental and physical health: self-compassion and mattering as mediators.

    PubMed

    Raque-Bogdan, Trisha L; Ericson, Sara K; Jackson, John; Martin, Helena M; Bryan, Nicole A

    2011-04-01

    Research shows a strong link between adult attachment and mental and physical health, but little is known about the mechanisms that underlie these relationships. The present study examined self-compassion and mattering, two constructs from positive psychology literature, as potential mediators. Using survey data from a sample of 208 college students, relationships among attachment, self-compassion, mattering, and functional health were explored. Correlational analyses indicated that attachment anxiety and avoidance were strongly related to the mental health component of functional health. Mediation analyses indicated that mattering and self-compassion mediated the relationships between attachment orientation (i.e., levels of avoidance and anxiety) and mental health. These findings suggest that individuals' abilities to be kind toward themselves and their sense of belonging and being important to others are pathways through which attachment orientation relates to mental health.

  7. 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

  8. Use of magnetically oriented orthogonal collagen scaffolds for hemi-corneal reconstruction and regeneration.

    PubMed

    Builles, Nicolas; Janin-Manificat, Hélène; Malbouyres, Marilyne; Justin, Virginie; Rovère, Marie-Rose; Pellegrini, Graziella; Torbet, Jim; Hulmes, David J S; Burillon, Carole; Damour, Odile; Ruggiero, Florence

    2010-11-01

    We recently showed that the highly organized architecture of the corneal stroma could be reproduced using scaffolds consisting of orthogonally aligned multilayers of collagen fibrils prepared using a high magnetic field. Here we show that such scaffolds permit the reconstruction in vitro of human hemi-corneas (stroma + epithelium), using primary human keratocytes and limbal stem cell derived human keratinocytes. On the surface of these hemi-corneas, a well-differentiated epithelium was formed, as determined both histologically and ultrastructurally and by the expression of characteristic markers. Within the stroma, the keratocytes aligned with the directions of the fibrils in the scaffold and synthesized a new extracellular matrix with typical collagen markers and small, uniform diameter fibrils. Finally, in vivo experiments using a rabbit model showed that these orthogonally oriented multi-layer scaffolds could be used to repair the anterior region of the stroma, leading to re-epithelialization and recovery of both transparency and ultrastructural organization. PMID:20708260

  9. Is compassion essential to nursing practice?

    PubMed

    Hem, Marit Helene; Heggen, Kristin

    2004-01-01

    The Norwegian Nurses' Association recently (2001) approved a new code of ethics that included compassion as one of the basic values in nursing care. This paper examines the idea of compassion in the context of the Bible story of the Good Samaritan using an analysis of qualitative data from nurses' clinical work with psychiatric patients. The aim is to show how the idea of compassion challenges nursing practice. Thereafter, the paper discusses the benefits of and premises for compassion in care work. The results show that nurses tend not to be guided by compassion in their work with patients. The organisation of the day-to-day work in the hospital ward, the division of labour between nurses and doctors, and the nurses' approach to nursing were identified as influencing this tendency. The study shows that compassion is a radical concept with a potential to promote greater respect for patients' dignity.

  10. A two-gyro compass

    NASA Astrophysics Data System (ADS)

    Kargu, L. I.; Kizlov, E. G.; Rybakov, V. I.

    1987-01-01

    A gyrocompass scheme employing two angular velocity transducers and direct positioning of the platform in the meridian plane is presented and analyzed theoretically. Test results are presented for an implementation of such a scheme using two floating gyroscopes. The theoretical and experimental results presented here show that a two-gyro compass based on gyroscopes with approximately equal technical characteristics (the difference must not be more than 50 percent) provide a faster response and a higher accuracy than one-gyro schemes.

  11. Transverse Spin Effects at COMPASS

    SciTech Connect

    Wollny, H.

    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.

  12. Robustness of the filamentation instability in arbitrarily oriented magnetic field: Full three dimensional calculation

    SciTech Connect

    Bret, A.

    2014-02-15

    The filamentation (Weibel) instability plays a key role in the formation of collisionless shocks which are thought to produce Gamma-Ray-Bursts and High-Energy-Cosmic-Rays in astrophysical environments. While it has been known for long that a flow-aligned magnetic field can completely quench the instability, it was recently proved in 2D that in the cold regime, such cancelation is possible if and only if the field is perfectly aligned. Here, this result is finally extended to a 3D geometry. Calculations are conducted for symmetric and asymmetric counter-streaming relativistic plasma shells. 2D results are retrieved in 3D: the instability can never be completely canceled for an oblique magnetic field. In addition, the maximum growth-rate is always larger for wave vectors lying in the plan defined by the flow and the oblique field. On the one hand, this bears consequences on the orientation of the generated filaments. On the other hand, it certifies 2D simulations of the problem can be performed without missing the most unstable filamentation modes.

  13. Robustness of the filamentation instability in arbitrarily oriented magnetic field: Full three dimensional calculation

    NASA Astrophysics Data System (ADS)

    Bret, A.

    2014-02-01

    The filamentation (Weibel) instability plays a key role in the formation of collisionless shocks which are thought to produce Gamma-Ray-Bursts and High-Energy-Cosmic-Rays in astrophysical environments. While it has been known for long that a flow-aligned magnetic field can completely quench the instability, it was recently proved in 2D that in the cold regime, such cancelation is possible if and only if the field is perfectly aligned. Here, this result is finally extended to a 3D geometry. Calculations are conducted for symmetric and asymmetric counter-streaming relativistic plasma shells. 2D results are retrieved in 3D: the instability can never be completely canceled for an oblique magnetic field. In addition, the maximum growth-rate is always larger for wave vectors lying in the plan defined by the flow and the oblique field. On the one hand, this bears consequences on the orientation of the generated filaments. On the other hand, it certifies 2D simulations of the problem can be performed without missing the most unstable filamentation modes.

  14. 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.

  15. 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 β, 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.

  16. Platelet-like hexagonal SrFe12O19 particles: Hydrothermal synthesis and their orientation in a magnetic field

    NASA Astrophysics Data System (ADS)

    Zhang, Tao; Peng, Xiaoling; Li, Jing; Yang, Yanting; Xu, Jingcai; Wang, Panfeng; Jin, Dingfeng; Jin, Hongxiao; Hong, Bo; Wang, Xinqing; Ge, Hongliang

    2016-08-01

    Platelet-like hexagonal SrFe12O19 particles were prepared by hydrothermal synthesis, and the effects of molar ratio of Fe/Sr (RFe/Sr) on the phase compositions, morphologies and magnetic properties of as-prepared samples were investigated. The optimum RFe/Sr is identified as 8:1. The hexagonal platelet-like particles are nano-scale in thickness and micro-scale in diameter. The low coercivity is a consequence of the large shape anisotropy of the as-synthesized particles. The platelet-like hexagonal SrFe12O19 particles were then dispersed in epoxy resin and formed ordered arrangement structure which took root in the curing epoxy matrix under an external magnetic field of 8000 Oe. The microstructures, morphologies and magnetic properties of the bulk samples orientated and nonaligned were studied. The platelet-like particles arrange with the platelet perpendicular to the magnetic field direction in the orientated samples. This demonstrates that the easy axis of the particle is perpendicular to the platelet, and that the magnetocrystalline anisotropy still plays a leading role in the changing effective anisotropy with the rapidly growing shape anisotropy. The remanence (Mr) of the bulk samples is changed obviously after orientation, while the coercivity nearly remains constant. That is, the maximum energy products (BH)max can be effectively adjusted by given a suitable magnetic field.

  17. Measurements of the magnetic field orientation in the Jovian ionosphere deduced from Pioneer 10 and 11 scintillation observations

    NASA Technical Reports Server (NTRS)

    Woo, R.; Yang, F.-C.

    1978-01-01

    In this paper the S band scintillations observed during the Pioneer 10 and 11 occultation measurements of Jupiter are analyzed. It is found that while the electron density irregularities are isotropic in the collision-dominated lower ionosphere, they are anisotropic in the upper ionosphere because of alignment along the magnetic field. By using Rytov's approximation the frequency spectrum of the log-amplitude scintillations is derived for a wave propagating in an anisotropic turbulent medium. It is shown that the spectrum depends to a large extent on the direction of anisotropy and is therefore useful for measuring the orientation of the magnetic field in regions that have not yet been probed by direct measurements. This new technique is applied to the Pioneer 10 and 11 observations, and is used to deduce the first measurements of magnetic field orientation in the ionosphere of Jupiter.

  18. The Role of Compassion in Moral Education.

    ERIC Educational Resources Information Center

    Ruiz, Pedro Ortega; Vallejos, Ramon Minguez

    1999-01-01

    Proposes compassion as a new model for moral education, emphasizing empathy as a foundation for educating for compassion. Argues that socioaffective experiences, acquisition of social skills, and awakening moral awareness are resources that enable the development of empathy. Suggests emotional guidance and observation-based tasks as practical…

  19. 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,…

  20. Sources of compass error in tunnel mapping

    SciTech Connect

    Yow, J.L. Jr.

    1982-05-01

    Six sets of compass measurements were performed in tunnels in igneous rock at the Nevada Test Site. The measurement sets were analyzed to evaluate the influences of wire mesh, rock bolts, mining equipment, and steel arches on compass-based geologic mapping work.

  1. Latest Results from the COMPASS Experiment

    NASA Astrophysics Data System (ADS)

    Stolarski, M.

    2016-02-01

    In this paper the latest results from the COMPASS experiment are presented. We show results from longitudinally and transversely polarised targets off which high energy muons are scattered. In addition the future plans of COMPASS as well as results of the beam test runs are also presented.

  2. Self-compassion: a concept analysis.

    PubMed

    Reyes, Darcel

    2012-06-01

    This concept analysis uses a modification of the evolutionary method (Rodgers, 1989) to identify the antecedent, attributes, and consequences of self-compassion. The antecedent to self-compassion is suffering, experienced in six possible realms: an event, a situation, an emotional response, a psychological state, spiritual alienation, or a physical response to illness or pain. Suffering has three dimensions: intrapersonal, interpersonal, and contextual. Suffering manifests as a pattern of decreased self-care, decreased ability to relate to others, and diminished autonomy. The attributes of self-compassion are self-kindness, mindfulness, commonality, and wisdom. The consequences of self-compassion are the opposite of the antecedent: self-compassion manifests as a pattern of increased self-care capacity, compassion for others, and increased relatedness, autonomy, and sense of self. Ideal, borderline and contrary cases of self-compassion provide examples of the concept. The article concludes with a discussion of implications of the concept of self-compassion for nursing practice and research.

  3. A continuum of compass spin models on the honeycomb lattice

    NASA Astrophysics Data System (ADS)

    Zou, Haiyuan; Liu, Bo; Zhao, Erhai; Liu, W. Vincent

    2016-05-01

    Quantum spin models with spatially dependent interactions, known as compass models, play an important role in the study of frustrated quantum magnetism. One example is the Kitaev model on the honeycomb lattice with spin-liquid (SL) ground states and anyonic excitations. Another example is the geometrically frustrated quantum 120° model on the same lattice whose ground state has not been unambiguously established. To generalize the Kitaev model beyond the exactly solvable limit and connect it with other compass models, we propose a new model, dubbed ‘the tripod model’, which contains a continuum of compass-type models. It smoothly interpolates the Ising model, the Kitaev model, and the quantum 120° model by tuning a single parameter {θ }\\prime , the angle between the three legs of a tripod in the spin space. Hence it not only unifies three paradigmatic spin models, but also enables the study of their quantum phase transitions. We obtain the phase diagram of the tripod model numerically by tensor networks in the thermodynamic limit. We show that the ground state of the quantum 120° model has long-range dimer order. Moreover, we find an extended spin-disordered (SL) phase between the dimer phase and an antiferromagnetic phase. The unification and solution of a continuum of frustrated spin models as outline here may be useful to exploring new domains of other quantum spin or orbital models.

  4. The effects of size and orientation on magnetic properties and exchange bias in Co3O4 mesoporous nanowires

    NASA Astrophysics Data System (ADS)

    Zeng, R.; Wang, J. Q.; Chen, Z. X.; Li, W. X.; Dou, S. X.

    2011-04-01

    Co3O4 mesoporous nanowires with average single crystalline grain sizes of about 8 nm, 12nm, 25 nm, and 45 nm were synthesized by sintering of microwave-assisted hydrothermal processed belt-Co(OH)2 precursors at 300-500 °C for 2 h. Microstructure analysis was conducted by x-ray diffraction, x-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), field emission SEM (FESEM), transmission electron microscopy (TEM), and high resolution TEM (HRTEM) to confirm the composition, structure, and orientation in the nanowires. Systematic magnetic measurements have also been conducted on the nanowires. It was found that the size and orientation have significant effects on the magnetic and exchange bias properties. The interesting finding was made that room temperature ferromagnetism appeared at 350 °C in the high orientation samples. Systematic comparison and analysis of the relationships among the grain size, microstructure, orientation (texture), surface electric structure (O vacancies), and defects with magnetic properties (ferromagnetism, coercive field, exchange bias, etc.) are presented in this work.

  5. Highlights from the COMPASS Experiment

    SciTech Connect

    Bradamante, F.

    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.

  6. Ocelli contribute to the encoding of celestial compass information in the Australian desert ant Melophorus bagoti.

    PubMed

    Schwarz, Sebastian; Albert, Laurence; Wystrach, Antoine; Cheng, Ken

    2011-03-15

    Many animal species, including some social hymenoptera, use the visual system for navigation. Although the insect compound eyes have been well studied, less is known about the second visual system in some insects, the ocelli. Here we demonstrate navigational functions of the ocelli in the visually guided Australian desert ant Melophorus bagoti. These ants are known to rely on both visual landmark learning and path integration. We conducted experiments to reveal the role of ocelli in the perception and use of celestial compass information and landmark guidance. Ants with directional information from their path integration system were tested with covered compound eyes and open ocelli on an unfamiliar test field where only celestial compass cues were available for homing. These full-vector ants, using only their ocelli for visual information, oriented significantly towards the fictive nest on the test field, indicating the use of celestial compass information that is presumably based on polarised skylight, the sun's position or the colour gradient of the sky. Ants without any directional information from their path-integration system (zero-vector) were tested, also with covered compound eyes and open ocelli, on a familiar training field where they have to use the surrounding panorama to home. These ants failed to orient significantly in the homeward direction. Together, our results demonstrated that M. bagoti could perceive and process celestial compass information for directional orientation with their ocelli. In contrast, the ocelli do not seem to contribute to terrestrial landmark-based navigation in M. bagoti.

  7. Magnetic information calibrates celestial cues during migration.

    PubMed

    Sandberg; Bäckman; Moore; Lõhmus

    2000-10-01

    Migratory birds use celestial and geomagnetic directional information to orient on their way between breeding and wintering areas. Cue-conflict experiments involving these two orientation cue systems have shown that directional information can be transferred from one system to the other by calibration. We designed experiments with four species of North American songbirds to: (1) examine whether these species calibrate orientation information from one system to the other; and (2) determine whether there are species-specific differences in calibration. Migratory orientation was recorded with two different techniques, cage tests and free-flight release tests, during autumn migration. Cage tests at dusk in the local geomagnetic field revealed species-specific differences: red-eyed vireo, Vireo olivaceus, and northern waterthrush, Seiurus noveboracensis, selected seasonally appropriate southerly directions whereas indigo bunting, Passerina cyanea, and grey catbird, Dumetella carolinensis, oriented towards the sunset direction. When tested in deflected magnetic fields, vireos and waterthrushes responded by shifting their orientation according to the deflection of the magnetic field, but buntings and catbirds failed to show any response to the treatment. In release tests, all four species showed that they had recalibrated their star compass on the basis of the magnetic field they had just experienced in the cage tests. Since release tests were done in the local geomagnetic field it seems clear that once the migratory direction is determined, most likely during the twilight period, the birds use their recalibrated star compass for orientation at departure. Copyright 2000 The Association for the Study of Animal Behaviour. PMID:11032648

  8. Planck intermediate results. XXXII. The relative orientation between the magnetic field and structures traced by interstellar dust

    NASA Astrophysics Data System (ADS)

    Planck Collaboration; Adam, R.; Ade, P. A. R.; Aghanim, N.; Alves, M. I. R.; Arnaud, M.; Arzoumanian, D.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Bartolo, N.; Battaner, E.; Benabed, K.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bonaldi, A.; Bonavera, L.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Boulanger, F.; Bracco, A.; Burigana, C.; Butler, R. C.; Calabrese, E.; Cardoso, J.-F.; Catalano, A.; Chamballu, A.; Chiang, H. C.; Christensen, P. R.; Colombi, S.; Colombo, L. P. L.; Combet, C.; Couchot, F.; Crill, B. P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Dickinson, C.; Diego, J. M.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Ducout, A.; Dupac, X.; Efstathiou, G.; Elsner, F.; Enßlin, T. A.; Eriksen, H. K.; Falgarone, E.; Ferrière, K.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Frejsel, A.; Galeotta, S.; Galli, S.; Ganga, K.; Ghosh, T.; Giard, M.; Gjerløw, E.; González-Nuevo, J.; Górski, K. M.; Gregorio, A.; Gruppuso, A.; Guillet, V.; Hansen, F. K.; Hanson, D.; Harrison, D. L.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hovest, W.; Huffenberger, K. M.; Hurier, G.; Jaffe, A. H.; Jaffe, T. R.; Jones, W. C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kisner, T. S.; Kneissl, R.; Knoche, J.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lamarre, J.-M.; Lasenby, A.; Lattanzi, M.; Lawrence, C. R.; Leonardi, R.; Levrier, F.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maffei, B.; Maino, D.; Mandolesi, N.; Maris, M.; Marshall, D. J.; Martin, P. G.; Martínez-González, E.; Masi, S.; Matarrese, S.; Mazzotta, P.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Natoli, P.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; Oppermann, N.; Oxborrow, C. A.; Pagano, L.; Pajot, F.; Paoletti, D.; Pasian, F.; Perdereau, O.; Perotto, L.; Perrotta, F.; Pettorino, V.; Piacentini, F.; Piat, M.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Pratt, G. W.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Reach, W. T.; Reinecke, M.; Remazeilles, M.; Renault, C.; Ristorcelli, I.; Rocha, G.; Roudier, G.; Rubiño-Martín, J. A.; Rusholme, B.; Sandri, M.; Santos, D.; Savini, G.; Scott, D.; Soler, J. D.; Spencer, L. D.; Stolyarov, V.; Sudiwala, R.; Sunyaev, R.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Umana, G.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Wade, L. A.; Wandelt, B. D.; Wehus, I. K.; Wiesemeyer, H.; Yvon, D.; Zacchei, A.; Zonca, A.

    2016-02-01

    The role of the magnetic field in the formation of the filamentary structures observed in the interstellar medium (ISM) is a debated topic owing to the paucity of relevant observations needed to test existing models. The Planck all-sky maps of linearly polarized emission from dust at 353 GHz provide the required combination of imaging and statistics to study the correlation between the structures of the Galactic magnetic field and of interstellar matter over the whole sky, both in the diffuse ISM and in molecular clouds. The data reveal that structures, or ridges, in the intensity map have counterparts in the Stokes Q and/or U maps. We focus our study on structures at intermediate and high Galactic latitudes, which cover two orders of magnitude in column density, from 1020 to 1022 cm-2. We measure the magnetic field orientation on the plane ofthe sky from the polarization data, and present an algorithm to estimate the orientation of the ridges from the dust intensity map. We use analytical models to account for projection effects. Comparing polarization angles on and off the structures, we estimate the mean ratio between the strengths of the turbulent and mean components of the magnetic field to be between 0.6 and 1.0, with a preferred value of 0.8. We find that the ridges are usually aligned with the magnetic field measured on the structures. This statistical trend becomes more striking for increasing polarization fraction and decreasing column density. There is no alignment for the highest column density ridges. We interpret the increase in alignment with polarization fraction as a consequence of projection effects. We present maps to show that the decrease in alignment for high column density is not due to a loss of correlation between the distribution of matter and the geometry of the magnetic field. In molecular complexes, we also observe structures perpendicular to the magnetic field, which, statistically, cannot be accounted for by projection effects. This

  9. Magnetic field sensor

    NASA Astrophysics Data System (ADS)

    Silva, Nicolas

    2012-09-01

    Earlier papers1-3 in this journal have described experiments on measuring the magnetic fields of current-carrying wires and permanent magnets using magnetic field probes of various kinds. This paper explains how to use an iPad and the free app MagnetMeter-3D Vector Magnetometer and Accelerometer4 (compass HD) to measure the magnetic fields.

  10. Micromagnetic simulation of the orientation dependence of grain boundary properties on the coercivity of Nd-Fe-B sintered magnets

    NASA Astrophysics Data System (ADS)

    Fujisaki, Jun; Furuya, Atsushi; Uehara, Yuji; Shimizu, Koichi; Ataka, Tadashi; Tanaka, Tomohiro; Oshima, Hirotaka; Ohkubo, Tadakatsu; Hirosawa, Satoshi; Hono, Kazuhiro

    2016-05-01

    This paper is focused on the micromagnetic simulation study about the orientation dependence of grain boundary properties on the coercivity of polycrystalline Nd-Fe-B sintered magnets. A multigrain object with a large number of meshes is introduced to analyze such anisotropic grain boundaries and the simulation is performed by combining the finite element method and the parallel computing. When the grain boundary phase parallel to the c-plane is less ferromagnetic the process of the magnetization reversal changes and the coercivity of the multigrain object increases. The simulations with various magnetic properties of the grain boundary phases are executed to search for the way to enhance the coercivity of polycrystalline Nd-Fe-B sintered magnets.

  11. Effect of the interplanetary magnetic field orientation and intensity in the mass and energy deposition on the Hermean surface

    NASA Astrophysics Data System (ADS)

    Varela, J.; Pantellini, F.; Moncuquet, M.

    2016-09-01

    The aim of the present study is to simulate the interaction between the solar wind and the Hermean magnetosphere. We use the MHD code PLUTO in spherical coordinates with an axisymmetric multipolar expansion of the Hermean magnetic field, to perform a set of simulations with different interplanetary magnetic field orientations and intensities. We fix the hydrodynamic parameters of the solar wind to study the distortions driven by the interplanetary magnetic field in the topology of the Hermean magnetosphere, leading to variations of the mass and energy deposition distributions, the integrated mass deposition, the oval aperture, the area covered by open magnetic field lines and the regions of efficient particle sputtering on the planet surface. The simulations show a correlation between the reconnection regions and the local maxima of plasma inflow and energy deposition on the planet surface.

  12. Distinctive uniaxial magnetic anisotropy and positive magnetoresistance in (110)-oriented Fe{sub 3}O{sub 4} films

    SciTech Connect

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

    2015-04-28

    Magnetite (Fe{sub 3}O{sub 4}) films were synthesized on (110)-oriented MgO, MgAl{sub 2}O{sub 4}, and SrTiO{sub 3} 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 Fe{sub 3}O{sub 4} film on MgAl{sub 2}O{sub 4} 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) SrTiO{sub 3} substrate with the largest lattice mismatch. Positive magnetoresistance in the (110) Fe{sub 3}O{sub 4} films was presumably affected by imperfect atomic arrangements at anti-phase boundaries.

  13. 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

  14. 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

  15. Transverse spin effects at COMPASS

    SciTech Connect

    Pesaro, G.

    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.

  16. 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: sxcao@shu.edu.cn; Cao, Shixun E-mail: sxcao@shu.edu.cn

    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.

  17. Pediatric novice nurses: examining compassion fatigue as a mediator between stress exposure and compassion satisfaction, burnout, and job satisfaction.

    PubMed

    Meyer, Rika M L; Li, Angela; Klaristenfeld, Jessica; Gold, Jeffrey I

    2015-01-01

    We investigated whether compassion fatigue mediated associations between nurse stress exposure and job satisfaction, compassion satisfaction, and burnout, controlling for pre-existing stress. The Life Events Checklist was administered to 251 novice pediatric nurses at the start of the nurse residency program (baseline) and 3 months after to assess pre-existing and current stress exposure. Compassion satisfaction, compassion fatigue, and burnout were assessed 3 months after baseline and job satisfaction 6 months after. Stress exposure significantly predicted lower compassion satisfaction and more burnout. Compassion fatigue partially mediated these associations. Results demonstrate a need for hospitals to prevent compassion fatigue in healthcare providers.

  18. Magnetic resonance imaging evaluation of acetabular orientation in normal Chinese children.

    PubMed

    Li, YiQiang; Liu, YuanZhong; Zhou, QingHe; Chen, WeiDong; Li, JingChun; Yu, LingJia; Xu, HongWen; Xie, DengHui

    2016-09-01

    There are no data regarding the acetabular orientation on magnetic resonance imaging (MRI); this study investigates the changes of acetabular orientation with age in normal Chinese children.We retrospectively analyzed the medical records of children who underwent hip MRI examination at our hospital from January 2009 to December 2015. A total of 180 patients with normal MRI reading of the hip joints were included and were divided into 14 groups according to age: from 6 months of age and then for each year from 1 to 16 years. The bony and cartilage acetabular anteversion angle (AAA), acetabular inclination angle (AIA), and acetabular index (AI) were measured. Total bony and cartilage femoral head coverage angles were measured on axial section total femoral head coverage angle (a-TCA) and coronal section total femoral head coverage angle (c-TCA).The mean bony AAA and AIA were 12.2 ± 2.5° and 50.9 ± 2.5°, respectively; both of them stayed constant from the age of 6 months to 16 years. Similar results were found in cartilage AAA (12.1 ± 2.5°) and AIA (41.2 ± 3.0°). There was no difference between bony and cartilage AAA, but bony AIA was significantly larger than cartilage AIA. Bony AI was 24.1 ± 2.4° at the age of 6 months, decreasing to 12.5 ± 2.3° by 12 to 13 years of age; cartilage AI (5.9 ± 1.7°) maintained a steady value with age. The mean bony a-TCA and c-TCA at 6 months were 117.0 ± 5.8° and 127.5 ± 5.1°, increasing to 144.5 ± 4.6° and 140.7 ± 2.5° at the age of 16 years. However, the cartilage a-TCA (145.2 ± 7.2°) and c-TCA (154.1 ± 5.7°) did not change significantly with age.Both bony and cartilage AAA and AIA remain constant up to the age of 16 years in normal Chinese pediatric population. Although the cartilage coverage of femoral head by the acetabulum remains unchanged with age, the bony coverage of femoral head increases. PMID:27631258

  19. Microwave complex permeability of Fe3O4 nanoflake composites with and without magnetic field-induced rotational orientation

    NASA Astrophysics Data System (ADS)

    Liu, Xianguo; Wing Or, Siu; Ming Leung, Chung; Ho, S. L.

    2013-05-01

    Magnetite (Fe3O4) nanoflakes with widths of 100-200 nm and thicknesses of 10-80 nm were prepared by a hydrothermal synthesis method. Fe3O4 nanoflake composites with and without magnetic field-induced rotational orientation of flake planes of Fe3O4 nanoflakes in paraffin binder were fabricated using 35 wt. % Fe3O4 nanoflakes. The rotationally oriented composite showed higher permeability and resonance frequency than the nonoriented one, and its value of (μ0-1)fr reached 214.8 GHz and exceeded the Snoek's limit. Considering a uniform and a random distribution of flake planes of Fe3O4 nanoflakes in the oriented and nonoriented composites, respectively, the complex permeability of both composites was calculated using the Landau-Lifshitz-Gilbert equation and the Bruggeman's effective medium theory in the 2-18 GHz microwave frequency range.

  20. Orientation Errors in Paleomagnetic Core Samples and Their Effects

    NASA Astrophysics Data System (ADS)

    Kono, M.

    2011-12-01

    In paleomagnetic studies, samples are often obtained as cylindrical cores by the use of engine drills. Two angles measured for the core in the field (the angle P between cylindrical axis and the horizontal plane, and the angle A between a horizontal direction in the core and the true north) are needed to describe the direction of magnetic remanence in geographic coordinates. These angles can be measured with an error of about 1 degree or less. The error in paleomagnetic directions are usually given by Fisher's semi-angle of 95% confidence (α 95), which is typically a few to ten degrees. It appears therefore that the orientation errors are negligibly small. However, this it not quite correct. There is no problem about the measurement of P, but the angle in the horizontal plane (A) is often measured by a magnetic compass, which is a source of large errors. In particular, large local magnetic anomalies often accompany volcanic rock terrain because of their strong magnetization. This effect is known quite a long time, but quantitative estimate of orientation errors is not available yet. We have obtained quite a large number of data (182 lavas, 903 samples) from Lundarhals area of Iceland. For more than 200 samples of these, three independent horizontal angles have been measured to estimate A; one by sun's direction, the second by reference to some landmark, and the third is by magnetic direction. Among the rest of samples, more than 600 have reference and magnetic directions. Only 30 samples are determined by magnetic compass alone. From a detailed analysis of these data, the following conclusions were obtained. (1) The difference between sun and reference azimuths are 0.0±0.6~circ (the mean and standard deviation in degrees, for n=203). This is small enough and can be ignored compared to other errors. Consequently, if either of these angles are available, we have almost error-free data for A. (2) The differences between the sun and magnetic azimuths are 0.5±7.8o (n

  1. The spin physics results from COMPASS

    SciTech Connect

    Kouznetsov, O.

    2015-04-10

    COMPASS (COmmon Muon and Proton Apparatus for Structure and Spectroscopy) is a fixed target experiment at CERN dedicated to studies of the spin structure of the nucleon and of the spectroscopy of hadrons. During the years 2002-2004, 2006-2007 and 2010-2011 the COMPASS collaboration has collected a large amount of data by scattering polarized 160(200) GeV/c muons on polarized {sup 6}LiD and NH{sub 3} targets. The COMPASS results on quark and gluon helicities are discussed, as well as results on transverse spin and transverse momentum effects in semi-inclusive deeply inelastic scattering.

  2. Neutron diffraction texture analysis for α-Al2O3 oriented by high magnetic field and sintering

    NASA Astrophysics Data System (ADS)

    Terada, N.; Suzuki, H. S.; Suzuki, T. S.; Kitazawa, H.; Sakka, Y.; Kaneko, K.; Metoki, N.

    2009-05-01

    We have performed neutron diffraction experiments on highly oriented α-Al2O3, obtained by slip casting under a magnetic field and sintering. In order to investigate the magnetic field, B, and sintering temperature, Tsint, dependence of the degree of alignment of the orientation, we used samples treated with systematically varied B up to 12 T and Tsint up to 1600 °C. The degree of alignment of the magnetic easy axis (the hexagonal c-axis) is rapidly enhanced by sintering above 1200 °C, which is coincident with the temperature at which crystal grains start to grow. The angular distribution of the c-axis for the sample sintered at 1600 °C, obtained by ω-scan neutron diffraction profiles, is almost coincident with the probability distribution calculated for the particle size two times larger than that in the starting material. We discuss the orientation process mechanism with sintering in light of the results of this analysis.

  3. Exploring compassion: a meta-analysis of the association between self-compassion and psychopathology.

    PubMed

    MacBeth, Angus; Gumley, Andrew

    2012-08-01

    Compassion has emerged as an important construct in studies of mental health and psychological therapy. Although an increasing number of studies have explored relationships between compassion and different facets of psychopathology there has as yet been no systematic review or synthesis of the empirical literature. We conducted a systematic search of the literature on compassion and mental health. We identified 20 samples from 14 eligible studies. All studies used the Neff Self Compassion Scale (Neff, 2003b). We employed meta-analysis to explore associations between self-compassion and psychopathology using random effects analyses of Fisher's Z correcting for attenuation arising from scale reliability. We found a large effect size for the relationship between compassion and psychopathology of r=-0.54 (95% CI=-0.57 to -0.51; Z=-34.02; p<.0001). Heterogeneity was significant in the analysis. There was no evidence of significant publication bias. Compassion is an important explanatory variable in understanding mental health and resilience. Future work is needed to develop the evidence base for compassion in psychopathology, and explore correlates of compassion and psychopathology.

  4. Exploring compassion: a meta-analysis of the association between self-compassion and psychopathology.

    PubMed

    MacBeth, Angus; Gumley, Andrew

    2012-08-01

    Compassion has emerged as an important construct in studies of mental health and psychological therapy. Although an increasing number of studies have explored relationships between compassion and different facets of psychopathology there has as yet been no systematic review or synthesis of the empirical literature. We conducted a systematic search of the literature on compassion and mental health. We identified 20 samples from 14 eligible studies. All studies used the Neff Self Compassion Scale (Neff, 2003b). We employed meta-analysis to explore associations between self-compassion and psychopathology using random effects analyses of Fisher's Z correcting for attenuation arising from scale reliability. We found a large effect size for the relationship between compassion and psychopathology of r=-0.54 (95% CI=-0.57 to -0.51; Z=-34.02; p<.0001). Heterogeneity was significant in the analysis. There was no evidence of significant publication bias. Compassion is an important explanatory variable in understanding mental health and resilience. Future work is needed to develop the evidence base for compassion in psychopathology, and explore correlates of compassion and psychopathology. PMID:22796446

  5. Morphology and orientational behavior of silica-coated spindle-type hematite particles in a magnetic field probed by small-angle X-ray scattering.

    PubMed

    Reufer, Mathias; Dietsch, Hervé; Gasser, Urs; Hirt, Ann; Menzel, Andreas; Schurtenberger, Peter

    2010-04-15

    Form factor and magnetic properties of silica-coated spindle-type hematite nanoparticles are determined from SAXS measurements with applied magnetic field and magnetometry measurements. The particle size, polydispersity and porosity are determined using a core-shell model for the form factor. The particles are found to align with their long axis perpendicular to the applied field. The orientational order is determined from the SAXS data and compared to the orientational order obtained from magnetometry. The direct access to both, the orientational order of the particles, and the magnetic moments allow one to determine the magnetic properties of the individual spindle-type hematite particles. We study the influence of the silica coating on the magnetic properties and find a fundamentally different behavior of silica-coated particles. The silica coating reduces the effective magnetic moment of the particles. This effect is enhanced with field strength and can be explained by superparamagnetic relaxation in the highly porous particles.

  6. Exploring the compassion deficit debate.

    PubMed

    Stenhouse, Rosie; Ion, Robin; Roxburgh, Michelle; Devitt, Patric Ffrench; Smith, Stephen D M

    2016-04-01

    Several recent high profile failures in the UK health care system have promoted strong debate on compassion and care in nursing. A number of papers articulating a range of positions within this debate have been published in this journal over the past two and a half years. These articulate a diverse range of theoretical perspectives and have been drawn together here in an attempt to bring some coherence to the debate and provide an overview of the key arguments and positions taken by those involved. In doing this we invite the reader to consider their own position in relation to the issues raised and to consider the impact of this for their own practice. Finally the paper offers some sense of how individual practitioners might use their understanding of the debates to ensure delivery of good nursing care.

  7. The Compass Experiment at CERN

    SciTech Connect

    Magnon, A.

    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.

  8. PanDA for COMPASS at JINR

    NASA Astrophysics Data System (ADS)

    Petrosyan, A. Sh.

    2016-09-01

    PanDA (Production and Distributed Analysis System) is a workload management system, widely used for data processing at experiments on Large Hadron Collider and others. COMPASS is a high-energy physics experiment at the Super Proton Synchrotron. Data processing for COMPASS runs locally at CERN, on lxbatch, the data itself stored in CASTOR. In 2014 an idea to start running COMPASS production through PanDA arose. Such transformation in experiment's data processing will allow COMPASS community to use not only CERN resources, but also Grid resources worldwide. During the spring and summer of 2015 installation, validation and migration work is being performed at JINR. Details and results of this process are presented in this paper.

  9. Recent results from COMPASS on exclusive muoproduction

    NASA Astrophysics Data System (ADS)

    Sandacz, Andrzej

    2016-02-01

    The 160 GeV polarised muon beam available at CERN, with positive or negative charge, makes COMPASS a unique place for GPD studies. The first GPD related COMPASS results come from exclusive vector meson production on transversely polarised protons and deuterons. The data were taken in 2003-2010 with large solid-state polarised targets, although without detection of recoil particles. Results on various transverse target spin dependent azimuthal asymmetries are presented and their relations to GPDs are discussed. The dedicated COMPASS GPD program started in 2012 with commissioning of a new long liquid hydrogen target and new detectors such as the large recoil proton detector and the large-angle electromagnetic calorimeter. It was followed by a short pilot 'DVCS run'. The performance of the setup and first results on DVCS and exclusive π0 channels have been demonstrated. The full data taking for the GPD program approved within COMPASS-II proposal is planned for 2016 and 2017.

  10. Recent results on hadron structure from COMPASS

    NASA Astrophysics Data System (ADS)

    Makke, Nour

    2016-05-01

    A review of the most recent measurements of longitudinal and transverse momentum dependent distributions and fragmentation functions accessed in the inclusive and the semi-inclusive deep inelastic scattering from COMPASS is given.

  11. Self-compassion in clinical practice.

    PubMed

    Germer, Christopher K; Neff, Kristin D

    2013-08-01

    Self-compassion is conceptualized as containing 3 core components: self-kindness versus self-judgment, common humanity versus isolation, and mindfulness versus overidentification, when relating to painful experiences. Research evidence demonstrates that self-compassion is related to psychological flourishing and reduced psychopathology. Mindful Self-Compassion (MSC) is an 8-week training program, meeting 2.5 hours each week, designed to help participants cultivate self-compassion. MSC contains a variety of meditations (e.g., loving-kindness, affectionate breathing) as well as informal practices for use in daily life (e.g., soothing touch, self-compassionate letter writing). A detailed clinical case illustrates the journey of a client through the 8 weeks of MSC training, describing the key features of each session and the client's response.

  12. Magnetic monitoring of earth and space

    USGS Publications Warehouse

    Love, Jeffrey 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.

  13. Revised Measurements and Interpretation of Magnetic Properties of Oriented CeF3 Single Crystals

    NASA Astrophysics Data System (ADS)

    Savinkov, A. V.; Korableva, S. L.; Tagirov, M. S.; Suzuki, H.; Matsumoto, K.; Abe, S.

    2016-06-01

    We report the magnetic susceptibility and magnetization of the single-crystal CeF3 precisely measured in external magnetic field-directed B\\vert \\vert c and Bbot c in wide ranges of temperatures from 1.8 to 300 K and magnetic field strength of 0-40 kG. Magnetic susceptibility, magnetization, and Ce^{3+} Stark energies of CeF3 have been calculated in the framework of the crystal field theory; good agreement with the experimental data has been achieved in the whole range of temperatures and magnetic fields without taking into account the mixed-valent Ce^{3+} -Ce^{4+} behavior or super-exchange interaction of cerium ions that have been proposed before. Anomalous behavior of the magnetic susceptibility near T ˜ 50 K is naturally explained in the crystal field model.

  14. Access to generalized parton distributions at COMPASS

    SciTech Connect

    Nowak, Wolf-Dieter

    2015-04-10

    A brief experimentalist's introduction to Generalized Parton Distributions (GPDs) is given. Recent COMPASS results are shown on transverse target-spin asymmetries in hard exclusive ρ{sup 0} production and their interpretation in terms of a phenomenological model as indication for chiral-odd, transverse GPDs is discussed. For deeply virtual Compton scattering, it is briefly outlined how to access GPDs and projections are shown for future COMPASS measurements.

  15. COMPASS Hadron Multiplicity Measurements and Fragmentation Functions

    NASA Astrophysics Data System (ADS)

    Stolarski, M.

    2016-03-01

    COMPASS preliminary results on hadron, pion and kaon multiplicities are presented. The hadron and pion data show a good agreement with (N)LO QCD expectations and some of these preliminary data have been already successfully incorporated in the global NLO QCD fits to world data. However, the results for kaon multiplicities, are different from the expectations of the DSS fit. There is also a tension between COMPASS and HERMES results, the only other experiment which measured kaon multiplicities in SIDIS.

  16. Manipulating magnetic anisotropy of the ultrathin Co2FeAl full-Heusler alloy film via growth orientation of the Pt buffer layer

    NASA Astrophysics Data System (ADS)

    Wen, F. S.; Xiang, J. Y.; Hao, C. X.; Zhang, F.; Lv, Y. F.; Wang, W. H.; Hu, W. T.; Liu, Z. Y.

    2013-12-01

    The ultrathin films of Co2FeAl (CFA) full-Heusler alloy were prepared between two Pt layers on MgO single crystals by magnetron sputtering. By controlling the substrate temperature, different growth orientations of the Pt underlayers were realized, and their effects were investigated on the magnetic anisotropy of the ultrathin CFA film. It was revealed that different Pt orientations lead to distinctly different magnetic anisotropy for the sandwiched ultrathin CFA films. The Pt (111) orientation favors the perpendicular anisotropy, while the appearance of partial Pt (001) orientation leads to the quick decrease of perpendicular anisotropy and the complete Pt (001) orientation gives rise to the in-plane anisotropy. With the Pt (111) orientation, the temperature and thickness-induced spin reorientation transitions were investigated in the sandwiched ultrathin CFA films.

  17. Mining-machine orientation control based on inertial, gravitational, and magnetic sensors. Report of Investigations/1990

    SciTech Connect

    Sammarco, J.J.

    1990-01-01

    The U.S. Bureau of Mines seeks to increase safety and efficiency in U.S. coal mines. One approach is to develop technology for automation of a continuous mining machine. Realization of an autonomous mining machine requires development of subsystems for machine intelligence, navigation-positioning, and computer control. The report focuses on investigation of one subsystem, an onboard heading system, which would be responsible for determining and controlling machine heading. The onboard heading system investigated is a multisensor system to determine machine heading, pitch, and roll. A directional gyroscope provides heading (yaw), fluxgate sensors provide a compass heading, and gravity-referenced clinometers give machine pitch and roll. The system utilizes a dedicated microcontroller networked to an external system of computers. Tram commands, supplied to the network from external computers, are executed by the onboard system. Sensor feedback is employed for closed-loop control of machine heading by controlling pivots and turns. The report discusses operating limitations and error sources of system sensors and presents test results of closed-loop control of machine heading.

  18. 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

  19. The lizard celestial compass detects linearly polarized light in the blue.

    PubMed

    Beltrami, Giulia; Parretta, Antonio; Petrucci, Ferruccio; Buttini, Paola; Bertolucci, Cristiano; Foà, Augusto

    2012-09-15

    The present study first examined whether ruin lizards, Podarcis sicula, are able to orientate using plane-polarized light produced by an LCD screen. Ruin lizards were trained and tested indoors, inside a hexagonal Morris water maze positioned under an LCD screen producing white polarized light with a single E-vector, which provided an axial cue. White polarized light did not include wavelengths in the UV. Lizards orientated correctly either when tested with E-vector parallel to the training axis or after 90 deg rotation of the E-vector direction, thus validating the apparatus. Further experiments examined whether there is a preferential region of the light spectrum to perceive the E-vector direction of polarized light. For this purpose, lizards reaching learning criteria under white polarized light were subdivided into four experimental groups. Each group was tested for orientation under a different spectrum of plane-polarized light (red, green, cyan and blue) with equalized photon flux density. Lizards tested under blue polarized light orientated correctly, whereas lizards tested under red polarized light were completely disoriented. Green polarized light was barely discernible by lizards, and thus insufficient for a correct functioning of their compass. When exposed to cyan polarized light, lizard orientation performances were optimal, indistinguishable from lizards detecting blue polarized light. Overall, the present results demonstrate that perception of linear polarization in the blue is necessary - and sufficient - for a proper functioning of the sky polarization compass of ruin lizards. This may be adaptively important, as detection of polarized light in the blue improves functioning of the polarization compass under cloudy skies, i.e. when the alternative celestial compass based on detection of the sun disk is rendered useless because the sun is obscured by clouds.

  20. /sup 2/H nuclear magnetic resonance of exchange-labeled gramicidin in an oriented lyotropic nematic phase

    SciTech Connect

    Davis, J.H.

    1988-01-12

    Lyotropic nematic liquid-crystalline phases, such as that formed by potassium laurate/decanol/KCl/water, are found to accept readily large amphiphilic solute molecules. Since these phases spontaneously orient in high magnetic fields, it becomes possible to obtain NMR spectra of biologically interesting solutes in an oriented axially symmetric environment. The amide hydrogens of the peptide backbone of gramicidin D (Dubos) were exchanged for deuterium, and the gramicidin was incorporated into a lyotropic nematic phase made with deuteriated buffer in place of water. /sup 2/H NMR spectra of oriented, exchange-labeled gramicidin were then obtained. The strong water signal from the deuteriated buffer was eliminated by using selective excitation and a polynomial subtraction procedure. The /sup 2/H NMR spectra at high temperature consist of twelve major quadrupolar doublets. The splittings observed are largely independent of temperature, suggesting a highly rigid backbone structure. Two of the doublets, which are chemically shifted relative to the others, show stronger temperature dependence. These two probably arise from the exchangeable amino hydrogens on the tryptophan indole moieties of the peptide. While we cannot yet assign all of the doublets, the spectra and nuclear magnetic relaxation data are consistent with a rigid slightly distorted ..beta../sub LD//sup 6.3/ helix undergoing axially symmetric reorientation about the director of the liquid-crystalline phase. The correlation time for the axially symmetric reorientation is determined by relaxation measurements to be about 10/sup -7/s.

  1. Compassion Fatigue and Compassion Satisfaction among Residential Child Care Workers: The Role of Personality Resources

    ERIC Educational Resources Information Center

    Zerach, Gadi

    2013-01-01

    This study assessed compassion fatigue (CF) and compassion satisfaction (CS) among Israeli residential child-care workers (RCWs) working in residential treatment facilities for children and youth at risk (N = 147) as compared to educational boarding schools workers (BSWs; N = 74). Furthermore, we assessed the relationship of potential…

  2. Compassion Fatigue, Compassion Satisfaction, and Burnout: Factors Impacting a Professional's Quality of Life

    ERIC Educational Resources Information Center

    Sprang, Ginny; Whitt-Woosley, Adrienne; Clark, James J.

    2007-01-01

    This study examined the relationship between three variables, compassion fatigue (CF), compassion satisfaction (CS), and burnout, and provider and setting characteristics in a sample of 1,121 mental health providers in a rural southern state. Respondents completed the Professional Quality of Life Scale as part of a larger survey of provider…

  3. Investigating Factors that Generate and Maintain Variation in Migratory Orientation: A Primer for Recent and Future Work

    PubMed Central

    Delmore, Kira E.; Liedvogel, Miriam

    2016-01-01

    The amazing accuracy of migratory orientation performance across the animal kingdom is facilitated by the use of magnetic and celestial compass systems that provide individuals with both directional and positional information. Quantitative genetics analyses in several animal systems suggests that migratory orientation has a strong genetic component. Nevertheless, the exact identity of genes controlling orientation remains largely unknown, making it difficult to obtain an accurate understanding of this fascinating behavior on the molecular level. Here, we provide an overview of molecular genetic techniques employed thus far, highlight the pros and cons of various approaches, generalize results from species-specific studies whenever possible, and evaluate how far the field has come since early quantitative genetics studies. We emphasize the importance of examining different levels of molecular control, and outline how future studies can take advantage of high-resolution tracking and sequencing techniques to characterize the genomic architecture of migratory orientation. PMID:26834592

  4. Investigating Factors that Generate and Maintain Variation in Migratory Orientation: A Primer for Recent and Future Work.

    PubMed

    Delmore, Kira E; Liedvogel, Miriam

    2016-01-01

    The amazing accuracy of migratory orientation performance across the animal kingdom is facilitated by the use of magnetic and celestial compass systems that provide individuals with both directional and positional information. Quantitative genetics analyses in several animal systems suggests that migratory orientation has a strong genetic component. Nevertheless, the exact identity of genes controlling orientation remains largely unknown, making it difficult to obtain an accurate understanding of this fascinating behavior on the molecular level. Here, we provide an overview of molecular genetic techniques employed thus far, highlight the pros and cons of various approaches, generalize results from species-specific studies whenever possible, and evaluate how far the field has come since early quantitative genetics studies. We emphasize the importance of examining different levels of molecular control, and outline how future studies can take advantage of high-resolution tracking and sequencing techniques to characterize the genomic architecture of migratory orientation. PMID:26834592

  5. Method for inferring the axis orientation of cylindrical magnetic flux rope based on single-point measurement

    NASA Astrophysics Data System (ADS)

    Rong, Z. J.; Wan, W. X.; Shen, C.; Zhang, T. L.; Lui, A. T. Y.; Wang, Yuming; Dunlop, M. W.; Zhang, Y. C.; Zong, Q.-G.

    2013-01-01

    We develop a new simple method for inferring the orientation of a magnetic flux rope, which is assumed to be a time-independent cylindrically symmetric structure via the direct single-point analysis of magnetic field structure. The model tests demonstrate that, for the cylindrical flux rope regardless of whether it is force-free or not, the method can consistently yield the axis orientation of the flux rope with higher accuracy and stability than the minimum variance analysis of the magnetic field and the Grad-Shafranov reconstruction technique. Moreover, the radial distance to the axis center and the current density can also be estimated consistently. Application to two actual flux transfer events observed by the four satellites of the Cluster mission demonstrates that the method is more appropriate to be used for the inner part of flux rope, which might be closer to the cylindrical structure, showing good agreement with the results obtained from the optimal Grad-Shafranov reconstruction and the least squares technique of Faraday's law, but fails to produce such agreement for the outer satellite that grazes the flux rope. Therefore, the method must be used with caution.

  6. Néel-type skyrmion lattice with confined orientation in the polar magnetic semiconductor GaV4S8

    NASA Astrophysics Data System (ADS)

    Kézsmárki, I.; Bordács, S.; Milde, P.; Neuber, E.; Eng, L. M.; White, J. S.; Rønnow, H. M.; Dewhurst, C. D.; Mochizuki, M.; Yanai, K.; Nakamura, H.; Ehlers, D.; Tsurkan, V.; Loidl, A.

    2015-11-01

    Following the early prediction of the skyrmion lattice (SkL)--a periodic array of spin vortices--it has been observed recently in various magnetic crystals mostly with chiral structure. Although non-chiral but polar crystals with Cnv symmetry were identified as ideal SkL hosts in pioneering theoretical studies, this archetype of SkL has remained experimentally unexplored. Here, we report the discovery of a SkL in the polar magnetic semiconductor GaV4S8 with rhombohedral (C3v) symmetry and easy axis anisotropy. The SkL exists over an unusually broad temperature range compared with other bulk crystals and the orientation of the vortices is not controlled by the external magnetic field, but instead confined to the magnetic easy axis. Supporting theory attributes these unique features to a new Néel-type of SkL describable as a superposition of spin cycloids in contrast to the Bloch-type SkL in chiral magnets described in terms of spin helices.

  7. Effects of Instructional Technology Integration Strategies in Orientation Programs on Nurse Retention in Magnet and Non-Magnet Hospitals

    ERIC Educational Resources Information Center

    Hancharik, Sharon D.

    2008-01-01

    This applied dissertation study was designed to learn if the increased use of instructional technology integration strategies in nursing orientation programs resulted in an increased retention of new nurses. The study attempted to uncover the current retention rate and use of technology at the participating hospitals. The data obtained from Magnet…

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

    SciTech Connect

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

    2013-09-04

    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 same way 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.

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

    DOE PAGES

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

    2013-09-04

    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 same way 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. Themore » range of field magnitudes for which the superconducting-tubes structure is favored shrinks when the field is more in-plane oriented.« less

  10. Quantum dynamics of the avian compass.

    PubMed

    Walters, Zachary B

    2014-10-01

    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 paper 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.

  11. Quantum dynamics of the avian compass

    NASA Astrophysics Data System (ADS)

    Walters, Zachary B.

    2014-10-01

    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 paper 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.

  12. Quantum dynamics of the avian compass.

    PubMed

    Walters, Zachary B

    2014-10-01

    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 paper 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. PMID:25375526

  13. Model for the orientation, magnetic field, and temperature dependence of the specific heat of CeCu6

    NASA Astrophysics Data System (ADS)

    Edelstein, A. S.

    1988-03-01

    The results of a model calculation of the orientation, magnetic field, and temperature dependence of the specific heat C of CeCu6 are found to be in good agreement with the single-crystal data of Amato et al. The model incorporates both the Kondo and crystal-field effects. It is suggested that the low-temperature Wilson's ratio C/Tχ, where χ is the susceptibility, may not change in an applied field H and that both C/T and χ at low temperatures as a function of H may be proportional to the many-body density of states at the energy μH.

  14. First results from EBW emission diagnostics on COMPASS

    SciTech Connect

    Zajac, J.; Preinhaelter, J.; Aftanas, M.; Bilkova, P.; Boehm, P.; Fuchs, V.; Weinzettl, V.; Zacek, F.; Nanobashvili, S.

    2012-10-15

    COMPASS tokamak shots at low magnetic field feature overdense plasmas during the extended current flat-top phase. The first harmonic of the electron cyclotron emission is completely cutoff for O and X modes and so the emission caused by electron Bernstein waves (EBWs) propagating obliquely with respect to the magnetic field and undergoing so called EBW-X-O conversion process can be observed. We perform an angular scan of the EBW emission during a set of comparable shots in order to determine the optimum antenna direction. A weak dependence of the radiative temperature on the antenna angles indicates an influence of multiple reflections from the vessel wall. The low temperature at the mode conversion region is responsible for the collisional damping of EBW, which can explain several times lower measured radiative temperature than the electron temperature measured by the Thomson scattering system.

  15. First results from EBW emission diagnostics on COMPASS.

    PubMed

    Zajac, J; Preinhaelter, J; Urban, J; Aftanas, M; Bílková, P; Böhm, P; Fuchs, V; Nanobashvili, S; Weinzettl, V; Zácek, F

    2012-10-01

    COMPASS tokamak shots at low magnetic field feature overdense plasmas during the extended current flat-top phase. The first harmonic of the electron cyclotron emission is completely cutoff for O and X modes and so the emission caused by electron Bernstein waves (EBWs) propagating obliquely with respect to the magnetic field and undergoing so called EBW-X-O conversion process can be observed. We perform an angular scan of the EBW emission during a set of comparable shots in order to determine the optimum antenna direction. A weak dependence of the radiative temperature on the antenna angles indicates an influence of multiple reflections from the vessel wall. The low temperature at the mode conversion region is responsible for the collisional damping of EBW, which can explain several times lower measured radiative temperature than the electron temperature measured by the Thomson scattering system.

  16. Current profilers and current meters: compass and tilt sensors errors and calibration

    NASA Astrophysics Data System (ADS)

    Le Menn, M.; Lusven, A.; Bongiovanni, E.; Le Dû, P.; Rouxel, D.; Lucas, S.; Pacaud, L.

    2014-08-01

    Current profilers and current meters have a magnetic compass and tilt sensors for relating measurements to a terrestrial reference frame. As compasses are sensitive to their magnetic environment, they must be calibrated in the configuration in which they will be used. A calibration platform for magnetic compasses and tilt sensors was built, based on a method developed in 2007, to correct angular errors and guarantee a measurement uncertainty for instruments mounted in mooring cages. As mooring cages can weigh up to 800 kg, it was necessary to find a suitable place to set up this platform, map the magnetic fields in this area and dimension the platform to withstand these loads. It was calibrated using a GPS positioning technique. The platform has a table that can be tilted to calibrate the tilt sensors. The measurement uncertainty of the system was evaluated. Sinusoidal corrections based on the anomalies created by soft and hard magnetic materials were tested, as well as manufacturers’ calibration methods.

  17. Electroless Co-P-Carbon Nanotube composite coating to enhance magnetic properties of grain-oriented electrical steel

    NASA Astrophysics Data System (ADS)

    Goel, Vishu; Anderson, Philip; Hall, Jeremy; Robinson, Fiona; Bohm, Siva

    2016-06-01

    The effect of Co-P-CNT coating on the magnetic properties of grain oriented electrical steel was investigated. To analyse the coating, Raman spectroscopy, Superconducting QUantum Interference Device (SQUID), single strip testing, Scanning Electron Microscopy (SEM) and talysurf surface profilometry were performed. Raman spectra showed the D and G band which corroborates the presence of Multi-Walled Carbon Nanotubes (MWCNT) in the coating. The magnetic nature of the coating was confirmed by SQUID results. Power loss results show an improvement ranging 13-15% after coating with Co-P-CNT. The resistivity of the coating was measured to be 104 μΩ cm. Loss separation graphs were plotted before and after coating to study the improvement in power loss. It was found that the coating helps in reducing the hysteresis loss. The thickness of the coating was found to be 414±40 nm. The surface profilometry results showed that the surface roughness improved after coating the sample.

  18. Neutron and X-ray single-crystal diffraction from protein microcrystals via magnetically oriented microcrystal arrays in gels.

    PubMed

    Tsukui, Shu; Kimura, Fumiko; Kusaka, Katsuhiro; Baba, Seiki; Mizuno, Nobuhiro; Kimura, Tsunehisa

    2016-07-01

    Protein microcrystals magnetically aligned in D2O hydrogels were subjected to neutron diffraction measurements, and reflections were observed for the first time to a resolution of 3.4 Å from lysozyme microcrystals (∼10 × 10 × 50 µm). This result demonstrated the possibility that magnetically oriented microcrystals consolidated in D2O gels may provide a promising means to obtain single-crystal neutron diffraction from proteins that do not crystallize at the sizes required for neutron diffraction structure determination. In addition, lysozyme microcrystals aligned in H2O hydrogels allowed structure determination at a resolution of 1.76 Å at room temperature by X-ray diffraction. The use of gels has advantages since the microcrystals are measured under hydrated conditions.

  19. Faraday instability on viscous ferrofluids in a horizontal magnetic field: Oblique rolls of arbitrary orientation

    NASA Astrophysics Data System (ADS)

    Mekhonoshin, V. V.; Lange, Adrian

    2002-06-01

    A linear stability analysis of the free surface of a horizontally unbounded ferrofluid layer of arbitrary depth subjected to vertical vibrations and a horizontal magnetic field is performed. A nonmonotonic dependence of the stability threshold on the magnetic field is found at high frequencies of the vibrations. The reasons for the decrease of the critical acceleration amplitude caused by a horizontal magnetic field are discussed. It is revealed that the magnetic field can be used to select the first unstable pattern of Faraday waves. In particular, a rhombic pattern as a superposition of two different oblique rolls can occur. A scaling law is presented which maps all data into one graph for the tested range of viscosities, frequencies, magnetic fields, and layer thicknesses.

  20. Influence of magnetic field on zebrafish activity and orientation in a plus maze.

    PubMed

    Osipova, Elena A; Pavlova, Vera V; Nepomnyashchikh, Valentin A; Krylov, Viacheslav V

    2016-01-01

    We describe an impact of the geomagnetic field (GMF) and its modification on zebrafish's orientation and locomotor activity in a plus maze with four arms oriented to the north, east, south and west. Zebrafish's directional preferences were bimodal in GMF: they visited two arms oriented in opposed directions (east-west) most frequently. This bimodal preference remained stable for same individuals across experiments divided by several days. When the horizontal GMF component was turned 90° clockwise, the preference accordingly shifted by 90° to arms oriented to the north and south. Other modifications of GMF (reversal of both vertical and horizontal GMF components; reversal of vertical component only; and reversal of horizontal component only) did not exert any discernible effect on the orientation of zebrafish. The 90° turn of horizontal component also resulted in a significant increase of fish's locomotor activity in comparison with the natural GMF. This increase became even more pronounced when the horizontal component was repeatedly turned by 90° and back with 1min interval between turns. Our results show that GMF and its variations should be taken into account when interpreting zebrafish's directional preferences and locomotor activity in mazes and other experimental devices. PMID:26589739

  1. 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.

  2. Biophysics of magnetic orientation: strengthening the interface between theory and experimental design

    PubMed Central

    Kirschvink, Joseph L.; Winklhofer, Michael; Walker, Michael M.

    2010-01-01

    The first demonstrations of magnetic effects on the behaviour of migratory birds and homing pigeons in laboratory and field experiments, respectively, provided evidence for the longstanding hypothesis that animals such as birds that migrate and home over long distances would benefit from possession of a magnetic sense. Subsequent identification of at least two plausible biophysical mechanisms for magnetoreception in animals, one based on biogenic magnetite and another on radical-pair biochemical reactions, led to major efforts over recent decades to test predictions of the two models, as well as efforts to understand the ultrastructure and function of the possible magnetoreceptor cells. Unfortunately, progress in understanding the magnetic sense has been challenged by: (i) the availability of a relatively small number of techniques for analysing behavioural responses to magnetic fields by animals; (ii) difficulty in achieving reproducible results using the techniques; and (iii) difficulty in development and implementation of new techniques that might bring greater experimental power. As a consequence, laboratory and field techniques used to study the magnetic sense today remain substantially unchanged, despite the huge developments in technology and instrumentation since the techniques were developed in the 1950s. New methods developed for behavioural study of the magnetic sense over the last 30 years include the use of laboratory conditioning techniques and tracking devices based on transmission of radio signals to and from satellites. Here we consider methodological developments in the study of the magnetic sense and present suggestions for increasing the reproducibility and ease of interpretation of experimental studies. We recommend that future experiments invest more effort in automating control of experiments and data capture, control of stimulation and full blinding of experiments in the rare cases where automation is impossible. We also propose new

  3. Compassion Fatigue: Strategies for Minimizing Impact on Aesthetic Medical Providers.

    PubMed

    Brennan, Connie

    2015-01-01

    Compassion fatigue is emotional, physical, and spiritual exhaustion from witnessing and absorbing the problems of others. Aesthetic providers are prone to becoming victims of compassion fatigue because of the stress of meeting the often overwhelming needs of patients. This article discusses what is known about compassion fatigue, what differentiates it from burnout, and how to recognize and combat it. PMID:26605823

  4. Compassion Fatigue among Social Work Students in Field Placements

    ERIC Educational Resources Information Center

    Harr, Cynthia; Moore, Brenda

    2011-01-01

    This pilot study, conducted with BSW and MSW field students at a public university in Southwestern United States, explored the psychological effect of compassion fatigue and compassion satisfaction on social work students in field placements. Results from the Professional Quality of Life Scale's compassion satisfaction and fatigue subscales…

  5. Understanding the Transformation of Compassion in Nurses Who Become Patients

    ERIC Educational Resources Information Center

    Pucino, Carrie L.

    2013-01-01

    The purpose of this study was to examine how nurses who become patients learn compassion toward patients in their professional practice, and examine the role of empathy in the process of learning compassion. The process of learning compassion represents a significant change in the way nurses perceive this aspect of practice. Therefore,…

  6. Self-Compassion and the Dynamics of Investigating Sexual Harassment

    ERIC Educational Resources Information Center

    Serri, Conchita Franco

    2006-01-01

    What role does compassion play in one's work? In the author's organization, the word "compassion" has been mostly linked to their values, mission, and programs. She has generally understood the concept of compassion as a deep feeling of empathy that flows from oneself towards others during certain situations and conditions. In her mind, "having…

  7. Beyond Assessment: Compassion as a Challenge to Catholic Teachers.

    ERIC Educational Resources Information Center

    Calfapietra, Elizabeth

    2002-01-01

    Argues that compassion trumps assessment and competition in the Catholic educator's classroom. Stresses that no strings can be attached to what the author refers to as teacherly love. Equates this compassion with the teachings of the Gospels. Describes teaching as a call to be an instrument of God's compassion. (Contains three references.) (NB)

  8. 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.

    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.

  9. The interaction of stars and magnetic field in the orientation system of night migrating birds. I. Autumn experiments with European Warblers (gen. Sylvia).

    PubMed

    Wiltschko, W; Wiltschko, R

    1975-06-01

    In the autumn migration periods of 1971, 1972, and 1973 the orientation behavior in registration cages of Sylvia communis, S. borin and S. cantillans was analyzed to find out what relative importance the birds assign to information from the stars and from the magnetic field for direction finding. We obtained the following results: 1. Under clear sky in the local earth's magnetic field (Control) the warblers showed directional preferences that corresponded to their expected migratory direction based on ringing recoveries. 2. When magnetic north was turned by 120 degrees to ESE (Test), all three species preferred on clear nights their migratory direction according to the magnetic field, in spite of contradicting information from the stars. 3. In a partly compensated magnetic field, which could not be used for orientation any more, no significant directional preference could be observed, although the stars were visible. Dividing these data into two groups according to whether the birds had been tested in Control or Test previously, we found a tendency for the directions selected here to depend upon the north direction of the magnetic field during the bird's previous tests. From this and from the observation that the concentration of orientation behavior decreases in the absence of stars, we derive the following orientational model: The magnetic field provides the primary directional information for migrating birds. The stars do not contain directional information in themselves, but they can become secondary sources of orientation when information from the magnetic field has been transferred to them previously. The importance of this mechanism lies in making it easier for the birds to maintain their migratory direction. The ecological advantages of such a system are discussed and critically compared to the other models of star orientation.

  10. On the Magnetic Field Orientation and Plasma Flows in Solar Filament Barbs

    NASA Astrophysics Data System (ADS)

    Litvinenko, Yuri E.

    2000-10-01

    Speeds of vertical flows in quiescent solar filaments are typically much less than the local Alfvén speed. This is why the flows in filament barbs can be modeled by perturbing a magnetostatic solution describing a balance between the Lorentz force, gravity, and gas pressure in a barb. This approach explains why some of the flows are neither aligned with the magnetic field nor controlled by gravity. Both the observed upflows and the magnetic field dips in barbs are likely to be caused by photospheric magnetic reconnection.

  11. Influence of crystallographic orientation on the magnetic properties of NiFe, Co, and Ni epitaxial fcc films grown on single-crystal substrates

    NASA Astrophysics Data System (ADS)

    Ohtani, Taiki; Kawai, Tetsuroh; Ohtake, Mitsuru; Futamoto, Masaaki

    2013-08-01

    Ni80Fe20 (at. %), Co, and Ni epitaxial thin films of fcc(100) and fcc(111) orientations are prepared on single-crystal substrates by using an ultra-high-vacuum radio-frequency magnetron sputtering system. The influence of the magnetocrystalline anisotropy on the magnetostriction behavior under in-plane rotating magnetic fields is investigated. Triangular waveforms are observed in the magnetostriction measurements under low rotating fields for films that show four-fold symmetry in the in-plane magnetic anisotropies. The magnetostriction behavior is related to the motion of ninety-degree magnetic domain walls in magnetically unsaturated films. The waveform changes from a triangular to a sinusoidal shape when magnetization saturation is approached under increasing magnetic field. On the other hand, films having almost isotropic in-plane magnetic properties show sinusoidal waveforms even when the films are not magnetically saturated.

  12. The neurobiological link between compassion and love

    PubMed Central

    Esch, Tobias; Stefano, George B.

    2011-01-01

    Summary Love and compassion exert pleasant feelings and rewarding effects. Besides their emotional role and capacity to govern behavior, appetitive motivation, and a general ‘positive state’, even ‘spiritual’ at times, the behaviors shown in love and compassion clearly rely on neurobiological mechanisms and underlying molecular principles. These processes and pathways involve the brain’s limbic motivation and reward circuits, that is, a finely tuned and profound autoregulation. This capacity to self-regulate emotions, approach behaviors and even pair bonding, as well as social contact in general, i.e., love, attachment and compassion, can be highly effective in stress reduction, survival and overall health. Yet, molecular biology is the basis of interpersonal neurobiology, however, there is no answer to the question of what comes first or is more important: It is a cybernetic capacity and complex circuit of autoregulation that is clearly ‘amazing’. PMID:21358615

  13. 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.

  14. Magnetic properties of in-plane oriented barium hexaferrite thin films prepared by direct current magnetron sputtering

    SciTech Connect

    Zhang, Xiaozhi; Yue, Zhenxing Meng, Siqin; Yuan, Lixin

    2014-12-28

    In-plane c-axis oriented Ba-hexaferrite (BaM) thin films were prepared on a-plane (112{sup ¯}0) sapphire (Al{sub 2}O{sub 3}) substrates by DC magnetron sputtering followed by ex-situ annealing. The DC magnetron sputtering was demonstrated to have obvious advantages over the traditionally used RF magnetron sputtering in sputtering rate and operation simplicity. The sputtering power had a remarkable influence on the Ba/Fe ratio, the hematite secondary phase, and the grain morphology of the as-prepared BaM films. Under 80 W of sputtering power, in-plane c-axis highly oriented BaM films were obtained. These films had strong magnetic anisotropy with high hysteresis loop squareness (M{sub r}/M{sub s} of 0.96) along the in-plane easy axis and low M{sub r}/M{sub s} of 0.03 along the in-plane hard axis. X-ray diffraction patterns and pole figures revealed that the oriented BaM films grew via an epitaxy-like growth process with the crystallographic relationship BaM (101{sup ¯}0)//α-Fe{sub 2}O{sub 3}(112{sup ¯}0)//Al{sub 2}O{sub 3}(112{sup ¯}0)

  15. 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.

  16. A continuum of compass spin models on the honeycomb lattice

    NASA Astrophysics Data System (ADS)

    Zou, Haiyuan; Liu, Bo; Zhao, Erhai; Liu, W. Vincent

    2016-05-01

    Quantum spin models with spatially dependent interactions, known as compass models, play an important role in the study of frustrated quantum magnetism. One example is the Kitaev model on the honeycomb lattice with spin-liquid ground states. Another example is the geometrically frustrated quantum 120° model whose ground state has not been unambiguously established. To generalize the Kitaev model beyond the exactly solvable limit and connect it with other models, we propose a new model, dubbed ``the tripod model,'' which contains a continuum of compass-type models. It not only unifies paradigmatic spin models, but also enables the study of their quantum phase transitions. We obtain the phase diagram of the tripod model numerically by tensor networks in the thermodynamic limit. We show that the ground state of the quantum 120° model has long-range dimer order. Moreover, we find an extended spin-disordered (spin-liquid) phase between the dimer phase and an antiferromagnetic phase. The unification and solution of a continuum of frustrated spin models as outline here may be useful to exploring new domains of other quantum spin or orbital models.

  17. Diffractive {rho}0 production at COMPASS

    SciTech Connect

    D'Hose, N.

    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.

  18. Nucleon Spin And Structure Studies With COMPASS

    SciTech Connect

    Platchkov, Stephane

    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.

  19. 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)

  20. Compassion fatigue and the adult protective services social worker.

    PubMed

    Bourassa, Dara Bergel

    2009-04-01

    Compassion fatigue is a relatively new term that describes the symptoms that are experienced by social workers and other helping professionals who work with clients experiencing trauma. This article defines the concept of compassion fatigue and relates compassion fatigue to Adult Protective Services (APS) social workers. It is proposed that APS social workers may be susceptible to the deleterious effects of compassion fatigue due to the nature of their work and environment. Suggestions for avoidance of compassion fatigue are also discussed, including self-care strategies and the need for continuing education regarding this phenomenon.

  1. 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.

  2. 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…

  3. Magnetic field-induced ferroelectric domain structure evolution and magnetoelectric coupling for [110]-oriented PMN-PT/Terfenol-D multiferroic composites

    NASA Astrophysics Data System (ADS)

    Fang, F.; Jing, W. Q.

    2016-01-01

    Magnetic field-induced polarization rotation and magnetoelectric coupling effects are studied for [110]-oriented (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3/Tb0.3Dy0.7Fe2(PMN-xPT/Terfenol-D) multiferroic composites. Two compositions of the [110]-oriented relaxor ferroelectric single crystals, PMN-28PT and PMN-33PT, are used. In [110]-oriented PMN-28PT, domains of rhombohedral (R) and monoclinic (MB) phases coexist prior to the magnetic loadings. Upon the applied magnetic loadings, phase transition from monoclinic MB to R phase occurs. In [110]-oriented PMN-33PT, domains are initially of mixed orthorhombic (O) and MB phases, and the phase transition from O to MB phase takes place upon the external magnetic loading. Compared to PMN-28PT, the PMN-33PT single crystal exhibits much finer domain boundary structure prior to the magnetic loadings. Upon the magnetic loadings, more domain variants are induced via the phase transition in PMN-33PT than that in PMN-28PT single crystal. The finer domain band structure and more domain variants contribute to stronger piezoelectric activity. As a result, the composite of PMN-33PT/Terfenol-D manifests a stronger ME coupling than PMN-28PT/Terfenol-D composite.

  4. Performance of an electro-optical solar compass in partially obscured Sun conditions.

    PubMed

    Bollanti, S; De Meis, D; Di Lazzaro, P; Flora, F; Gallerano, G P; Mezi, L; Murra, D; Vicca, D

    2016-04-20

    Solar compasses are designed to accurately find true North on sunny days. However, no data on their performance are available when sunlight is partially blocked, e.g., by a cloud. We have measured, for the first time to the best of our knowledge, the performance of one of the most accurate electro-optical solar compasses (accuracy better than 0.01  deg) as a function of the solar disk obscuration during the Sun's eclipse on 20 March 2015. The measurements show that the accuracy level is mainly dependent on the asymmetry of the obscuration with respect to the main axis of the optical detection system and, to a lesser extent, on the percentage of the solar disk covered. In particular, azimuth measurement suffered a maximum deviation of 0.08 deg when 35% of the solar disk was asymmetrically obscured. The deviation was smaller when 46% of the solar disk was more symmetrically obscured. This experiment demonstrates that, even in the case of a partially obscured Sun, the electro-optical solar compass maintains an accuracy better than magnetic and electronic compasses. PMID:27140077

  5. Performance of an electro-optical solar compass in partially obscured Sun conditions.

    PubMed

    Bollanti, S; De Meis, D; Di Lazzaro, P; Flora, F; Gallerano, G P; Mezi, L; Murra, D; Vicca, D

    2016-04-20

    Solar compasses are designed to accurately find true North on sunny days. However, no data on their performance are available when sunlight is partially blocked, e.g., by a cloud. We have measured, for the first time to the best of our knowledge, the performance of one of the most accurate electro-optical solar compasses (accuracy better than 0.01  deg) as a function of the solar disk obscuration during the Sun's eclipse on 20 March 2015. The measurements show that the accuracy level is mainly dependent on the asymmetry of the obscuration with respect to the main axis of the optical detection system and, to a lesser extent, on the percentage of the solar disk covered. In particular, azimuth measurement suffered a maximum deviation of 0.08 deg when 35% of the solar disk was asymmetrically obscured. The deviation was smaller when 46% of the solar disk was more symmetrically obscured. This experiment demonstrates that, even in the case of a partially obscured Sun, the electro-optical solar compass maintains an accuracy better than magnetic and electronic compasses.

  6. Suffering and compassion: The links among adverse life experiences, empathy, compassion, and prosocial behavior.

    PubMed

    Lim, Daniel; DeSteno, David

    2016-03-01

    Experiencing past adversity traditionally has been linked to negative life outcomes. However, emerging evidence suggests that heterogeneity exists with respect to links between adversity and resilience, with adversity often enhancing cooperation in the face of joint suffering. Here, the authors present 2 studies designed to examine if the severity of past adversity is associated with an enduring propensity for empathy-mediated compassion, and, if so, whether the resulting compassion directly is, in turn, linked to behavior meant to relieve the suffering of others. Using both MTurk and laboratory-based paradigms, the authors find that increasing severity of past adversity predicts increased empathy, which in turn, is linked to a stable tendency to feel compassion for others in need. In addition, they demonstrate that the resulting individual differences in compassion appear to engender behavioral responses meant to assist others (i.e., charitable giving, helping a stranger).

  7. Oriented-assembly of hollow FePt nanochains with tunable catalytic and magnetic properties

    NASA Astrophysics Data System (ADS)

    Liu, Jialong; Xia, Tianyu; Wang, Shouguo; Yang, Guang; Dong, Bowen; Wang, Chao; Ma, Qidi; Sun, Young; Wang, Rongming

    2016-06-01

    Hollow nanoparticles with large surface areas exhibit a lot of advantages for applications such as catalysis and energy storage. Furthermore, their performance can be manipulated by their deliberate assemblies. Dispersive hollow FePt nanospheres have been assembled into one-dimensional hollow FePt nanochains under the magnetic fields at room temperature. Based on the activation of galvanic replacement at different reaction stages, the size of hollow FePt nanochains can be deliberately manipulated varying from 20 nm to 300 nm, together with the length changing from 200 nm to 10 μm. The competition between movement of paramagnetic Fe3+ ions and shape recovering due to thermal fluctuations plays a critical effect on the structure of contact area between hollow nanospheres, leading to perforative structures. Compared with commercial Pt/C, well aligned hollow FePt nanochains show greatly enhanced catalytic activities in the methanol oxidation reaction (MOR) due to more favorable mass flow. Magnetic measurements indicate that the magnetic properties including Curie temperature and saturation magnetization can be tuned by the control of the size and shape of hollow nanochains.Hollow nanoparticles with large surface areas exhibit a lot of advantages for applications such as catalysis and energy storage. Furthermore, their performance can be manipulated by their deliberate assemblies. Dispersive hollow FePt nanospheres have been assembled into one-dimensional hollow FePt nanochains under the magnetic fields at room temperature. Based on the activation of galvanic replacement at different reaction stages, the size of hollow FePt nanochains can be deliberately manipulated varying from 20 nm to 300 nm, together with the length changing from 200 nm to 10 μm. The competition between movement of paramagnetic Fe3+ ions and shape recovering due to thermal fluctuations plays a critical effect on the structure of contact area between hollow nanospheres, leading to perforative

  8. Oriented nanometric aggregates of partially inverted zinc ferrite: One-step processing and tunable high-frequency magnetic properties

    SciTech Connect

    Sai, Ranajit; Endo, Yasushi; Shimada, Yutaka; Yamaguchi, Masahiro; Shivashankar, S. A.

    2015-05-07

    In this work, it is demonstrated that the in situ growth of oriented nanometric aggregates of partially inverted zinc ferrite can potentially pave a way to alter and tune magnetocrystalline anisotropy that, in turn, dictates ferromagnetic resonance frequency (f{sub FMR}) by inducing strain due to aggregation. Furthermore, the influence of interparticle interaction on magnetic properties of the aggregates is investigated. Mono-dispersed zinc ferrite nanoparticles (<5 nm) with various degrees of aggregation were prepared through decomposition of metal-organic compounds of zinc (II) and iron (III) in an alcoholic solution under controlled microwave irradiation, below 200 °C. The nanocrystallites were found to possess high degree of inversion (>0.5). With increasing order of aggregation in the samples, saturation magnetization (at 5 K) is found to decrease from 38 emu/g to 24 emu/g, while coercivity is found to increase gradually by up to 100% (525 Oe to 1040 Oe). Anisotropy-mediated shift of f{sub FMR} has also been measured and discussed. In essence, the result exhibits an easy way to control the magnetic characteristics of nanocrystalline zinc ferrite, boosted with significant degree of inversion, at GHz frequencies.

  9. The influence of punching process on residual stress and magnetic domain structure of non-oriented silicon steel

    NASA Astrophysics Data System (ADS)

    Cao, Hongzhi; Hao, Linpo; Yi, Jingwen; Zhang, Xianglin; Luo, Zhonghan; Chen, Shenglin; Li, Rongfeng

    2016-05-01

    The main purpose of this paper is to investigate the influence of punching process on residual stress and magnetic domain structure. The residual stress in non-oriented silicon steel after punching process was measured by nanoindentation. The maximum depth was kept constant as 300 nm during nanoindentation. The material around indentation region exhibited no significant pile-up deformation. The calculation of residual stress was based on the Suresh theoretical model. Our experimental results show that residual compressive stress was generated around the sheared edge after punching. The width of residual stress affected zone by punching was around 0.4-0.5 mm. After annealing treatment, the residual stress was significantly decreased. Magnetic domain structure was observed according to the Bitter method. The un-annealed sample exhibited complicated domain patterns, and the widths of the magnetic domains varied between 3 μm and 8 μm. Most of the domain patterns of the annealed sample were 180°-domains and 90°-domains, and the widths of the domains decreased to 1-3 μm.

  10. Oriented nanometric aggregates of partially inverted zinc ferrite: One-step processing and tunable high-frequency magnetic properties

    NASA Astrophysics Data System (ADS)

    Sai, Ranajit; Endo, Yasushi; Shimada, Yutaka; Yamaguchi, Masahiro; Shivashankar, S. A.

    2015-05-01

    In this work, it is demonstrated that the in situ growth of oriented nanometric aggregates of partially inverted zinc ferrite can potentially pave a way to alter and tune magnetocrystalline anisotropy that, in turn, dictates ferromagnetic resonance frequency (fFMR) by inducing strain due to aggregation. Furthermore, the influence of interparticle interaction on magnetic properties of the aggregates is investigated. Mono-dispersed zinc ferrite nanoparticles (<5 nm) with various degrees of aggregation were prepared through decomposition of metal-organic compounds of zinc (II) and iron (III) in an alcoholic solution under controlled microwave irradiation, below 200 °C. The nanocrystallites were found to possess high degree of inversion (>0.5). With increasing order of aggregation in the samples, saturation magnetization (at 5 K) is found to decrease from 38 emu/g to 24 emu/g, while coercivity is found to increase gradually by up to 100% (525 Oe to 1040 Oe). Anisotropy-mediated shift of fFMR has also been measured and discussed. In essence, the result exhibits an easy way to control the magnetic characteristics of nanocrystalline zinc ferrite, boosted with significant degree of inversion, at GHz frequencies.

  11. Compassion training alters altruism and neural responses to suffering

    PubMed Central

    Weng, Helen Y.; Fox, Andrew S.; Shackman, Alexander J.; Stodola, Diane E.; Caldwell, Jessica Z. K.; Olson, Matthew C.; Rogers, Gregory M.; Davidson, Richard J.

    2013-01-01

    Compassion is a key motivator of altruistic behavior, but little is known about individuals’ capacity to cultivate compassion through training. We examined whether compassion may be systematically trained by testing whether (i) short-term compassion training increases altruistic behavior, and (ii) individual differences in altruism are associated with training-induced changes in neural responses to suffering. In healthy young adults, we found that compassion training increased altruistic redistribution of funds to a victim encountered outside of the training context. Furthermore, greater altruistic behavior after compassion training was associated with altered activation in regions implicated in social cognition and emotion regulation, including the inferior parietal cortex, dorsolateral prefrontal cortex (DLPFC), and DLPFC connectivity with the nucleus accumbens. These results suggest that compassion can be cultivated with training, where greater altruistic behavior may emerge from increased engagement in neural systems implicated in understanding the suffering of others, executive and emotional control, and reward processing. PMID:23696200

  12. Transmedulla Neurons in the Sky Compass Network of the Honeybee (Apis mellifera) Are a Possible Site of Circadian Input.

    PubMed

    Zeller, Maximilian; Held, Martina; Bender, Julia; Berz, Annuska; Heinloth, Tanja; Hellfritz, Timm; Pfeiffer, Keram

    2015-01-01

    Honeybees are known for their ability to use the sun's azimuth and the sky's polarization pattern for spatial orientation. Sky compass orientation in bees has been extensively studied at the behavioral level but our knowledge about the underlying neuronal systems and mechanisms is very limited. Electrophysiological studies in other insect species suggest that neurons of the sky compass system integrate information about the polarization pattern of the sky, its chromatic gradient, and the azimuth of the sun. In order to obtain a stable directional signal throughout the day, circadian changes between the sky polarization pattern and the solar azimuth must be compensated. Likewise, the system must be modulated in a context specific way to compensate for changes in intensity, polarization and chromatic properties of light caused by clouds, vegetation and landscape. The goal of this study was to identify neurons of the sky compass pathway in the honeybee brain and to find potential sites of circadian and neuromodulatory input into this pathway. To this end we first traced the sky compass pathway from the polarization-sensitive dorsal rim area of the compound eye via the medulla and the anterior optic tubercle to the lateral complex using dye injections. Neurons forming this pathway strongly resembled neurons of the sky compass pathway in other insect species. Next we combined tracer injections with immunocytochemistry against the circadian neuropeptide pigment dispersing factor and the neuromodulators serotonin, and γ-aminobutyric acid. We identified neurons, connecting the dorsal rim area of the medulla to the anterior optic tubercle, as a possible site of neuromodulation and interaction with the circadian system. These neurons have conspicuous spines in close proximity to pigment dispersing factor-, serotonin-, and GABA-immunoreactive neurons. Our data therefore show for the first time a potential interaction site between the sky compass pathway and the circadian

  13. Transmedulla Neurons in the Sky Compass Network of the Honeybee (Apis mellifera) Are a Possible Site of Circadian Input

    PubMed Central

    Zeller, Maximilian; Held, Martina; Bender, Julia; Berz, Annuska; Heinloth, Tanja; Hellfritz, Timm; Pfeiffer, Keram

    2015-01-01

    Honeybees are known for their ability to use the sun’s azimuth and the sky’s polarization pattern for spatial orientation. Sky compass orientation in bees has been extensively studied at the behavioral level but our knowledge about the underlying neuronal systems and mechanisms is very limited. Electrophysiological studies in other insect species suggest that neurons of the sky compass system integrate information about the polarization pattern of the sky, its chromatic gradient, and the azimuth of the sun. In order to obtain a stable directional signal throughout the day, circadian changes between the sky polarization pattern and the solar azimuth must be compensated. Likewise, the system must be modulated in a context specific way to compensate for changes in intensity, polarization and chromatic properties of light caused by clouds, vegetation and landscape. The goal of this study was to identify neurons of the sky compass pathway in the honeybee brain and to find potential sites of circadian and neuromodulatory input into this pathway. To this end we first traced the sky compass pathway from the polarization-sensitive dorsal rim area of the compound eye via the medulla and the anterior optic tubercle to the lateral complex using dye injections. Neurons forming this pathway strongly resembled neurons of the sky compass pathway in other insect species. Next we combined tracer injections with immunocytochemistry against the circadian neuropeptide pigment dispersing factor and the neuromodulators serotonin, and γ-aminobutyric acid. We identified neurons, connecting the dorsal rim area of the medulla to the anterior optic tubercle, as a possible site of neuromodulation and interaction with the circadian system. These neurons have conspicuous spines in close proximity to pigment dispersing factor-, serotonin-, and GABA-immunoreactive neurons. Our data therefore show for the first time a potential interaction site between the sky compass pathway and the circadian

  14. 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.

  15. Horizon Based Orientation Estimation for Planetary Surface Navigation

    NASA Technical Reports Server (NTRS)

    Bouyssounouse, X.; Nefian, A. V.; Deans, M.; Thomas, A.; Edwards, L.; Fong, T.

    2016-01-01

    Planetary rovers navigate in extreme environments for which a Global Positioning System (GPS) is unavailable, maps are restricted to relatively low resolution provided by orbital imagery, and compass information is often lacking due to weak or not existent magnetic fields. However, an accurate rover localization is particularly important to achieve the mission success by reaching the science targets, avoiding negative obstacles visible only in orbital maps, and maintaining good communication connections with ground. This paper describes a horizon solution for precise rover orientation estimation. The detected horizon in imagery provided by the on board navigation cameras is matched with the horizon rendered over the existing terrain model. The set of rotation parameters (roll, pitch yaw) that minimize the cost function between the two horizon curves corresponds to the rover estimated pose.

  16. Oriented-assembly of hollow FePt nanochains with tunable catalytic and magnetic properties.

    PubMed

    Liu, Jialong; Xia, Tianyu; Wang, Shouguo; Yang, Guang; Dong, Bowen; Wang, Chao; Ma, Qidi; Sun, Young; Wang, Rongming

    2016-06-01

    Hollow nanoparticles with large surface areas exhibit a lot of advantages for applications such as catalysis and energy storage. Furthermore, their performance can be manipulated by their deliberate assemblies. Dispersive hollow FePt nanospheres have been assembled into one-dimensional hollow FePt nanochains under the magnetic fields at room temperature. Based on the activation of galvanic replacement at different reaction stages, the size of hollow FePt nanochains can be deliberately manipulated varying from 20 nm to 300 nm, together with the length changing from 200 nm to 10 μm. The competition between movement of paramagnetic Fe(3+) ions and shape recovering due to thermal fluctuations plays a critical effect on the structure of contact area between hollow nanospheres, leading to perforative structures. Compared with commercial Pt/C, well aligned hollow FePt nanochains show greatly enhanced catalytic activities in the methanol oxidation reaction (MOR) due to more favorable mass flow. Magnetic measurements indicate that the magnetic properties including Curie temperature and saturation magnetization can be tuned by the control of the size and shape of hollow nanochains.

  17. Magnetic localization and orientation of the capsule endoscope based on a random complex algorithm

    PubMed Central

    He, Xiaoqi; Zheng, Zizhao; Hu, Chao

    2015-01-01

    The development of the capsule endoscope has made possible the examination of the whole gastrointestinal tract without much pain. However, there are still some important problems to be solved, among which, one important problem is the localization of the capsule. Currently, magnetic positioning technology is a suitable method for capsule localization, and this depends on a reliable system and algorithm. In this paper, based on the magnetic dipole model as well as magnetic sensor array, we propose nonlinear optimization algorithms using a random complex algorithm, applied to the optimization calculation for the nonlinear function of the dipole, to determine the three-dimensional position parameters and two-dimensional direction parameters. The stability and the antinoise ability of the algorithm is compared with the Levenberg–Marquart algorithm. The simulation and experiment results show that in terms of the error level of the initial guess of magnet location, the random complex algorithm is more accurate, more stable, and has a higher “denoise” capacity, with a larger range for initial guess values. PMID:25914561

  18. Oriented-assembly of hollow FePt nanochains with tunable catalytic and magnetic properties.

    PubMed

    Liu, Jialong; Xia, Tianyu; Wang, Shouguo; Yang, Guang; Dong, Bowen; Wang, Chao; Ma, Qidi; Sun, Young; Wang, Rongming

    2016-06-01

    Hollow nanoparticles with large surface areas exhibit a lot of advantages for applications such as catalysis and energy storage. Furthermore, their performance can be manipulated by their deliberate assemblies. Dispersive hollow FePt nanospheres have been assembled into one-dimensional hollow FePt nanochains under the magnetic fields at room temperature. Based on the activation of galvanic replacement at different reaction stages, the size of hollow FePt nanochains can be deliberately manipulated varying from 20 nm to 300 nm, together with the length changing from 200 nm to 10 μm. The competition between movement of paramagnetic Fe(3+) ions and shape recovering due to thermal fluctuations plays a critical effect on the structure of contact area between hollow nanospheres, leading to perforative structures. Compared with commercial Pt/C, well aligned hollow FePt nanochains show greatly enhanced catalytic activities in the methanol oxidation reaction (MOR) due to more favorable mass flow. Magnetic measurements indicate that the magnetic properties including Curie temperature and saturation magnetization can be tuned by the control of the size and shape of hollow nanochains. PMID:26971675

  19. Magnetic-field-induced orientation of photosynthetic reaction centers as revealed by time-resolved W-band EPR of spin-correlated radical pairs

    SciTech Connect

    Berthold, T.; Bechtold, M.; Heinen, U.; Link, G.; Poluektov, O.; Utschig, L.; Tang, J.; Thurnauer, M.C.; Kothe, G.

    1999-12-09

    The spin-polarized W-band EPR spectra of the secondary radical pair in plant photosystem 1 indicate a magnetic-field-induced orientation of the photosynthetic reaction centers in the field of the EPR spectrometer. This orientation arises due to the anisotropy of the diamagnetic susceptibility of the reaction center protein. Analysis of the angular-dependent EPR spectra on the basis of the spin-correlated radical pair concept provides new information on the cofactor arrangement in plant photosystem 1.

  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