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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. 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.

  4. 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.

  5. Magnetic compass orientation in birds and its physiological basis.

    PubMed

    Wiltschko, Wolfgang; Wiltschko, Roswitha

    2002-10-01

    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. Lateralization of magnetic compass orientation in a migratory bird

    NASA Astrophysics Data System (ADS)

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

    2002-10-01

    Lateralization of brain functions, once believed to be a human characteristic, has now been found to be widespread among vertebrates. In birds, asymmetries of visual functions are well studied, with each hemisphere being specialized for different tasks. Here we report lateralized functions of the birds' visual system associated with magnetoperception, resulting in an extreme asymmetry of sensing the direction of the magnetic field. We found that captive migrants tested in cages with the magnetic field as the only available orientation cue were well oriented in their appropriate migratory direction when using their right eye only, but failed to show a significant directional preference when using their left eye. This implies that magnetoreception for compass orientation, assumed to take place in the eyes alongside the visual processes, is strongly lateralized, with a marked dominance of the right eye/left brain hemisphere.

  7. 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.

  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. 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.

  11. 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...

  12. Night-migratory garden warblers can orient with their magnetic compass using the left, the right or both eyes.

    PubMed

    Hein, Christine Maira; Zapka, Manuela; Heyers, Dominik; Kutzschbauch, Sandra; Schneider, Nils-Lasse; Mouritsen, Henrik

    2010-04-06

    Several studies have suggested that the magnetic compass of birds is located only in the right eye. However, here we show that night-migrating garden warblers (Sylvia borin) are able to perform magnetic compass orientation with both eyes open, with only the left eye open and with only the right eye open. We did not observe any clear lateralization of magnetic compass orientation behaviour in this migratory songbird, and, therefore, it seems that the suggested all-or-none lateralization of magnetic compass orientation towards the right eye only cannot be generalized to all birds, and that the answer to the question of whether magnetic compass orientation in birds is lateralized is probably not as simple as suggested previously.

  13. 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.

  14. 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.

  15. 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.

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

    PubMed

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

    2010-04-06

    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.

  17. 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

  18. Magnetic compass orientation of European robins under 565 nm green light

    NASA Astrophysics Data System (ADS)

    Wiltschko, Wolfgang; Gesson, Marcus; Wiltschko, Roswitha

    2001-07-01

    European robins tested under monochromatic green light with a peak wavelength of 565 nm at an intensity of 2.1 mW m-2 in the local geomagnetic field preferred their migratory direction, heading southward in autumn and northward in spring. Inverting of the vertical component of the magnetic field caused the robins to reverse their headings, indicating that the birds used a magnetic inclination compass to locate their migratory direction. The behavior recorded under green light at an intensity of 2.1 mW m-2 is thus not different from that previously recorded under "white" light; it represents normal migratory orientation.

  19. Magnetic compass orientation of European robins under 565 nm green light.

    PubMed

    Wiltschko, W; Gesson, M; Wiltschko, R

    2001-09-01

    European robins tested under monochromatic green light with a peak wavelength of 565 nm at an intensity of 2.1 mW m-2 in the local geomagnetic field preferred their migratory direction, heading southward in autumn and northward in spring. Inverting of the vertical component of the magnetic field caused the robins to reverse their headings, indicating that the birds used a magnetic inclination compass to locate their migratory direction. The behavior recorded under green light at an intensity of 2.1 mW m-2 is thus not different from that previously recorded under "white" light; it represents normal migratory orientation.

  20. Magnetic compass orientation in European robins is dependent on both wavelength and intensity of light.

    PubMed

    Muheim, Rachel; Bäckman, Johan; Akesson, Susanne

    2002-12-01

    Magnetic compass orientation in birds has been shown to be light dependent. Results from behavioural studies indicate that magnetoreception capabilities are disrupted under light of peak wavelengths longer than 565 nm, and shifts in orientation have been observed at higher light intensities (43-44x10(15) quanta s(-1) m(-2)). To investigate further the function of the avian magnetic compass with respect to wavelength and intensity of light, we carried out orientation cage experiments with juvenile European robins, caught during their first autumn migration, exposed to light of 560.5 nm (green), 567.5 nm (green-yellow) and 617 nm (red) wavelengths at three different intensities (1 mW m(-2), 5 mW m(-2) and 10 mW m(-2)). We used monochromatic light of a narrow wavelength range (half bandwidth of 9-11 nm, compared with half bandwidths ranging between 30 nm and 70 nm used in other studies) and were thereby able to examine the magnetoreception mechanism in the expected transition zone between oriented and disoriented behaviour around 565 nm in more detail. We show (1) that European robins show seasonally appropriate migratory directions under 560.5 nm light, (2) that they are completely disoriented under 567.5 nm light under a broad range of intensities, (3) that they are able to orient under 617 nm light of lower intensities, although into a direction shifted relative to the expected migratory one, and (4) that magnetoreception is intensity dependent, leading to disorientation under higher intensities. Our results support the hypothesis that birds possess a light-dependent magnetoreception system based on magnetically sensitive, antagonistically interacting spectral mechanisms, with at least one high-sensitive short-wavelength mechanism and one low-sensitive long-wavelength mechanism.

  1. Sanderlings (Calidris alba) have a magnetic compass: orientation experiments during spring migration in Iceland.

    PubMed

    Gudmundsson, G A; Sandberg, R

    2000-10-01

    The migratory orientation of sanderlings (Calidris alba) was investigated with cage experiments during the spring migration in southwest Iceland. Sanderlings were exposed to 90 degrees counterclockwise-shifted magnetic fields under both clear skies and natural overcast. Clear sky control tests resulted in a northerly mean direction, in agreement with predictions based on ringing recovery data and earlier visual observations of departing flocks. Sanderlings closely followed experimental deflections of magnetic fields when tested under clear skies. Control experiments under natural overcast resulted in a bimodal distribution approximately coinciding with the magnetic north-south axis. Overcast tests did not reveal any predictable response to the experimental treatment, but instead resulted in a non-significant circular distribution. The time of orientation experiments in relation to the tidal cycle affects the motivation of the birds to depart, as shown by the lower directional scatter of headings of individuals tested within the appropriate tidal window under clear skies. Sanderlings were significantly more likely to become inactive under overcast conditions than under clear sky conditions. The results demonstrate, for the first time, that a wader species such as the sanderling possesses a magnetic compass and suggest that magnetic cues are of primary directional importance. However, overcast experiments indicate that both celestial and geomagnetic information are needed for sanderlings to realize a seasonally appropriate migratory orientation.

  2. A magnetic compass aids monarch butterfly migration.

    PubMed

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

    2014-06-24

    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.

  3. 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

  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.

  5. Magnetic compass orientation of migratory birds in the presence of a 1.315 MHz oscillating field.

    PubMed

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

    2005-02-01

    The radical pair model of magnetoreception predicts that magnetic compass orientation can be disrupted by high frequency magnetic fields in the Megahertz range. European robins, Erithacus rubecula, were tested under monochromatic 565 nm green light in 1.315 MHz fields of 0.48 microT during spring and autumn migration, with 1.315 MHz being the frequency that matches the energetic splitting induced by the local geomagnetic field. The birds' responses depended on the alignment of the oscillating field with respect to the static geomagnetic field: when the 1.315 MHz field was aligned parallel with the field lines, birds significantly preferred northerly directions in spring and southerly directions in autumn. These preferences reflect normal migratory orientation, with the variance slightly increased compared to control tests in the geomagnetic field alone or to tests in a 7.0 MHz field. However, in the 1.315 MHz field aligned at a 24 degrees angle to the field lines, the birds were disoriented in both seasons, indicating that the high frequency field interfered with magnetoreception. These finding are in agreement with theoretical predictions and support the assumption of a radical-pair mechanism underlying the processes mediating magnetic compass information in birds.

  6. 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...

  7. 'Fixed-axis' magnetic orientation by an amphibian: non-shoreward-directed compass orientation, misdirected homing or positioning a magnetite-based map detector in a consistent alignment relative to the magnetic field?

    PubMed

    Phillips, John B; Borland, S Chris; Freake, Michael J; Brassart, Jacques; Kirschvink, Joseph L

    2002-12-01

    Experiments were carried out to investigate the earlier prediction that prolonged exposure to long-wavelength (>500 nm) light would eliminate homing orientation by male Eastern red-spotted newts Notophthalmus viridescens. As in previous experiments, controls held in outdoor tanks under natural lighting conditions and tested in a visually uniform indoor arena under full-spectrum light were homeward oriented. As predicted, however, newts held under long-wavelength light and tested under either full-spectrum or long-wavelength light (>500 nm) failed to show consistent homeward orientation. The newts also did not orient with respect to the shore directions in the outdoor tanks in which they were held prior to testing. Unexpectedly, however, the newts exhibited bimodal orientation along a more-or-less 'fixed' north-northeast-south-southwest magnetic axis. The orientation exhibited by newts tested under full-spectrum light was indistinguishable from that of newts tested under long-wavelength light, although these two wavelength conditions have previously been shown to differentially affect both shoreward compass orientation and homing orientation. To investigate the possibility that the 'fixed-axis' response of the newts was mediated by a magnetoreception mechanism involving single-domain particles of magnetite, natural remanent magnetism (NRM) was measured from a subset of the newts. The distribution of NRM alignments with respect to the head-body axis of the newts was indistinguishable from random. Furthermore, there was no consistent relationship between the NRM of individual newts and their directional response in the overall sample. However, under full-spectrum, but not long-wavelength, light, the alignment of the NRM when the newts reached the 20 cm radius criterion circle in the indoor testing arena (estimated by adding the NRM alignment measured from each newt to its magnetic bearing) was non-randomly distributed. These findings are consistent with the earlier

  8. Orienteering: The Race With a Compass

    ERIC Educational Resources Information Center

    Boyd, Ellsworth

    1978-01-01

    Orienteering, a Scandinavian sport that has recently become popular in the United States, combines outdoor adventure, practical skills, physical fitness and fun. Here it is used to help young students develop survival skills using a compass. (Author/RK)

  9. Robins have a magnetic compass in both eyes.

    PubMed

    Hein, Christine Maira; Engels, Svenja; Kishkinev, Dmitry; Mouritsen, Henrik

    2011-03-31

    Arising from W. Wiltschko et al. 419, 467-470 (2002); Wiltschko et al. replyThe magnetic compass of migratory birds is embedded in the visual system and it has been reported by Wiltschko et al. that European Robins, Erithacus rubecula, cannot show magnetic compass orientation using their left eye only. This has led to the notion that the magnetic compass should be located only in the right eye of birds. However, a complete right lateralization of the magnetic compass would be very surprising, and functional neuroanatomical data have questioned this notion. Here we show that the results of Wiltschko et al. could not be independently confirmed using double-blind protocols. European Robins can perform magnetic compass orientation with both eyes open, with the left eye open only, and with the right eye open only. No clear lateralization is observed.

  10. 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

  11. 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…

  12. Light-Activated Magnetic Compass in Birds

    NASA Astrophysics Data System (ADS)

    Solov'yov, Ilia A.; Greiner, Walter

    Migrating birds fly thousand miles without having a map, or a GPS unit. But they may carry their own sensitive navigational tool, which allows them "see" the Earth's magnetic field. Here we review the important physical and chemical constraints on a possible compass sensor and discuss the suggestion that radical pairs in a photoreceptor cryptochrome might provide a biological realization for a magnetic compass. Finally, we review the current evidence supporting a role for radical pair reactions in the magnetic compass of birds.

  13. 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).

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

    NASA Astrophysics Data System (ADS)

    Cochran, William W.; Mouritsen, Henrik; Wikelski, Martin

    2004-04-01

    Night migratory songbirds can use stars, sun, geomagnetic field, and polarized light for orientation when tested in captivity. We studied the interaction of magnetic, stellar, and twilight orientation cues in free-flying songbirds. We exposed Catharus thrushes to eastward-turned magnetic fields during the twilight period before takeoff and then followed them for up to 1100 kilometers. Instead of heading north, experimental birds flew westward. On subsequent nights, the same individuals migrated northward again. We suggest that birds orient with a magnetic compass calibrated daily from twilight cues. This could explain how birds cross the magnetic equator and deal with declination.

  15. Visual but not trigeminal mediation of magnetic compass information in a migratory bird.

    PubMed

    Zapka, Manuela; Heyers, Dominik; Hein, Christine M; Engels, Svenja; Schneider, Nils-Lasse; Hans, Jörg; Weiler, Simon; Dreyer, David; Kishkinev, Dmitry; Wild, J Martin; Mouritsen, Henrik

    2009-10-29

    Magnetic compass information has a key role in bird orientation, but the physiological mechanisms enabling birds to sense the Earth's magnetic field remain one of the unresolved mysteries in biology. Two biophysical mechanisms have become established as the most promising magnetodetection candidates. The iron-mineral-based hypothesis suggests that magnetic information is detected by magnetoreceptors in the upper beak and transmitted through the ophthalmic branch of the trigeminal nerve to the brain. The light-dependent hypothesis suggests that magnetic field direction is sensed by radical pair-forming photopigments in the eyes and that this visual signal is processed in cluster N, a specialized, night-time active, light-processing forebrain region. Here we report that European robins with bilateral lesions of cluster N are unable to show oriented magnetic-compass-guided behaviour but are able to perform sun compass and star compass orientation behaviour. In contrast, bilateral section of the ophthalmic branch of the trigeminal nerve in European robins did not influence the birds' ability to use their magnetic compass for orientation. These data show that cluster N is required for magnetic compass orientation in this species and indicate that it may be specifically involved in processing of magnetic compass information. Furthermore, the data strongly suggest that a vision-mediated mechanism underlies the magnetic compass in this migratory songbird, and that the putative iron-mineral-based receptors in the upper beak connected to the brain by the trigeminal nerve are neither necessary nor sufficient for magnetic compass orientation in European robins.

  16. 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.

  17. nCompass Service Oriented Architecture for Tacit Collaboration Services

    NASA Astrophysics Data System (ADS)

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

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

  18. 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)...

  19. 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)...

  20. 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)...

  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, 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)...

  3. 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…

  4. 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...

  5. 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.

  6. On the use of magnets to disrupt the physiological compass of birds.

    PubMed

    Wang, K; Mattern, E; Ritz, T

    2006-10-04

    Behavioral researchers have attached magnets to birds during orientation experiments, assuming that such magnets will disrupt their ability to obtain magnetic information. Here, we investigate the effect of an attached magnet on the ability to derive directional information from a radical-pair based compass mechanism. We outline in some detail the geometrical symmetries that would allow a bird to identify magnetic directions in a radical-pair based compass. We show that the artificial field through an attached magnet will quickly disrupt the birds' ability to distinguish pole-ward from equator-ward headings, but that much stronger fields are necessary to disrupt their ability to detect the magnetic axis. Together with estimates of the functional limits of a radical-pair based compass, our calculations suggest that artificial fields of comparable size to the geomagnetic field are not generally sufficient to render a radical-pair based compass non-functional.

  7. Zebra finches have a light-dependent magnetic compass similar to migratory birds.

    PubMed

    Pinzon-Rodriguez, Atticus; Muheim, Rachel

    2017-04-01

    Birds have a light-dependent magnetic compass that provides information about the spatial alignment of the geomagnetic field. It is proposed to be located in the avian retina and mediated by a light-induced, radical-pair mechanism involving cryptochromes as sensory receptor molecules. To investigate how the behavioural responses of birds under different light spectra match with cryptochromes as the primary magnetoreceptor, we examined the spectral properties of the magnetic compass in zebra finches. We trained birds to relocate a food reward in a spatial orientation task using magnetic compass cues. The birds were well oriented along the trained magnetic compass axis when trained and tested under low-irradiance 521 nm green light. In the presence of a 1.4 MHz radio-frequency electromagnetic (RF)-field, the birds were disoriented, which supports the involvement of radical-pair reactions in the primary magnetoreception process. Birds trained and tested under 638 nm red light showed a weak tendency to orient ∼45 deg clockwise of the trained magnetic direction. Under low-irradiance 460 nm blue light, they tended to orient along the trained magnetic compass axis, but were disoriented under higher irradiance light. Zebra finches trained and tested under high-irradiance 430 nm indigo light were well oriented along the trained magnetic compass axis, but disoriented in the presence of a RF-field. We conclude that magnetic compass responses of zebra finches are similar to those observed in nocturnally migrating birds and agree with cryptochromes as the primary magnetoreceptor, suggesting that light-dependent, radical-pair-mediated magnetoreception is a common property for all birds, including non-migratory species.

  8. 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

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

    PubMed

    Etheredge, J A; Perez, S M; Taylor, O R; Jander, R

    1999-11-23

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

  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 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

  12. Development of lateralization of the magnetic compass in a migratory bird.

    PubMed

    Gehring, Dennis; Wiltschko, Wolfgang; Güntürkün, Onur; Denzau, Susanne; Wiltschko, Roswitha

    2012-10-22

    The magnetic compass of a migratory bird, the European robin (Erithacus rubecula), was shown to be lateralized in favour of the right eye/left brain hemisphere. However, this seems to be a property of the avian magnetic compass that is not present from the beginning, but develops only as the birds grow older. During first migration in autumn, juvenile robins can orient by their magnetic compass with their right as well as with their left eye. In the following spring, however, the magnetic compass is already lateralized, but this lateralization is still flexible: it could be removed by covering the right eye for 6 h. During the following autumn migration, the lateralization becomes more strongly fixed, with a 6 h occlusion of the right eye no longer having an effect. This change from a bilateral to a lateralized magnetic compass appears to be a maturation process, the first such case known so far in birds. Because both eyes mediate identical information about the geomagnetic field, brain asymmetry for the magnetic compass could increase efficiency by setting the other hemisphere free for other processes.

  13. The puzzle of magnetic resonance effect on the magnetic compass of migratory birds.

    PubMed

    Kavokin, K V

    2009-07-01

    Experiments on the effect of radio-frequency (RF) magnetic fields on the magnetic compass orientation of migratory birds are analyzed using the theory of magnetic resonance. The results of these experiments were earlier interpreted within the radical-pair model of magnetoreception. However, the consistent analysis shows that the amplitudes of the RF fields used are far too small to noticeably influence electron spins in organic radicals. Other possible agents that could mediate the birds' response to the RF fields are discussed, but apparently no known physical system can be responsible for this effect.

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

    PubMed Central

    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

  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. 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

  17. 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.

  18. Night-migratory songbirds possess a magnetic compass in both eyes.

    PubMed

    Engels, Svenja; Hein, Christine Maira; 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.

  19. 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

  20. Magnetic Orientation in Birds and Other Animals

    NASA Astrophysics Data System (ADS)

    Wiltschko, Wolfgang

    The use of the geomagnetic field for compass orientation is widespread among animals, with two types of magnetic compass mechanisms described: an shape inclination compass in birds, turtles and salamanders and a shape polarity compass in arthropods, fishes and mammals. Additionally, some vertebrates appear to derive positional information from the total intensity and/or inclination of the geomagnetic field. For magnetoreception by animals, two models are currently discussed, the shape Radical Pair model assuming light-dependent processes by specialized photopigments, and the shape Magnetite hypothesis proposing magnetoreception by crystals of magnetite, Fe304. Behavioral experiments with migratory birds, testing them under monochromatic lights and subjecting them to a brief, strong pulse that could reverse the magnetization of magnetite particles, produced evidence for both mechanisms. However, monochromatic lights affect old, experienced and young birds alike, whereas the pulse affects only experienced birds, leaving young, inexperienced birds unaffected. These observations suggest that a radical pair mechanism provides birds with directional information for their innate magnetic compass and a magnetite-based mechanism possibly mediates information about total intensity for indicating position.

  1. Calibration of magnetic and celestial compass cues in migratory birds--a review of cue-conflict experiments.

    PubMed

    Muheim, Rachel; Moore, Frank R; Phillips, John B

    2006-01-01

    Migratory birds use multiple sources of compass information for orientation, including the geomagnetic field, the sun, skylight polarization patterns and star patterns. In this paper we review the results of cue-conflict experiments designed to determine the relative importance of the different compass mechanisms, and how directional information from these compass mechanisms is integrated. We focus on cue-conflict experiments in which the magnetic field was shifted in alignment relative to natural celestial cues. Consistent with the conclusions of earlier authors, our analyses suggest that during the premigratory season, celestial information is given the greatest salience and used to recalibrate the magnetic compass by both juvenile and adult birds. Sunset polarized light patterns from the region of the sky near the horizon appear to provide the calibration reference for the magnetic compass. In contrast, during migration, a majority of experiments suggest that birds rely on the magnetic field as the primary source of compass information and use it to calibrate celestial compass cues, i.e. the relative saliency of magnetic and celestial cues is reversed. An alternative possibility, however, is suggested by several experiments in which birds exposed to a cue conflict during migration appear to have recalibrated the magnetic compass, i.e. their response is similar to that of birds exposed to cue conflicts during the premigratory season. The general pattern to emerge from these analyses is that birds exposed to the cue conflict with a view of the entire sunset sky tended to recalibrate the magnetic compass, regardless of whether the cue conflict occurred during the premigratory or migratory period. In contrast, birds exposed to the cue conflict in orientation funnels and registration cages that restricted their view of the region of sky near the horizon (as was generally the case in experiments carried out during the migratory season) did not recalibrate the magnetic

  2. 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...

  3. 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...

  4. 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...

  5. 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

  6. 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.

  7. 46 CFR 108.715 - Magnetic compass and gyrocompass.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ....715 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS...-propelled unit in ocean or coastwise service must have a magnetic compass. (b) Each self-propelled unit of 1,600 gross tons and over in ocean or coastwise service must have a gyrocompass in addition to...

  8. 46 CFR 108.715 - Magnetic compass and gyrocompass.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ....715 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS...-propelled unit in ocean or coastwise service must have a magnetic compass. (b) Each self-propelled unit of 1,600 gross tons and over in ocean or coastwise service must have a gyrocompass in addition to...

  9. 46 CFR 108.715 - Magnetic compass and gyrocompass.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ....715 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS...-propelled unit in ocean or coastwise service must have a magnetic compass. (b) Each self-propelled unit of 1,600 gross tons and over in ocean or coastwise service must have a gyrocompass in addition to...

  10. 46 CFR 108.715 - Magnetic compass and gyrocompass.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ....715 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS...-propelled unit in ocean or coastwise service must have a magnetic compass. (b) Each self-propelled unit of 1,600 gross tons and over in ocean or coastwise service must have a gyrocompass in addition to...

  11. 46 CFR 108.715 - Magnetic compass and gyrocompass.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ....715 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS...-propelled unit in ocean or coastwise service must have a magnetic compass. (b) Each self-propelled unit of 1,600 gross tons and over in ocean or coastwise service must have a gyrocompass in addition to...

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

    PubMed

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

    2009-09-25

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

  13. The interaction of stars and magnetic field in the orientation system of night migrating birds. II. Spring experiments with european robins (Erithacus rubecula).

    PubMed

    Wiltschko, W; Wiltschko, R

    1975-01-01

    To investigate the relative importance of stellar and magnetic cues for the compass orientation of night migrating birds, 45 European robins (Erithacus rubecula) were tested in automatically registering cages with view of the clear natural night sky. One group was tested in the natural local geomagnetic field, the other group in a field pointing to 120 degrees ESE; birds from both groups were additionally tested in a magnetic field the horizontal component of which was compensated. The observed orientation behavior leads to the conclusion that star compass and magnetic compass are not independent, but that they are interlinked in the way that the star compass is established by information from the magnetic compass.

  14. 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

  15. Navigation: bat orientation using Earth's magnetic field.

    PubMed

    Holland, Richard A; Thorup, Kasper; Vonhof, Maarten J; Cochran, William W; Wikelski, Martin

    2006-12-07

    Bats famously orientate at night by echolocation, but this works over only a short range, and little is known about how they navigate over longer distances. Here we show that the homing behaviour of Eptesicus fuscus, known as the big brown bat, can be altered by artificially shifting the Earth's magnetic field, indicating that these bats rely on a magnetic compass to return to their home roost. This finding adds to the impressive array of sensory abilities possessed by this animal for navigation in the dark.

  16. The quantum needle of the avian magnetic compass

    PubMed Central

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

    2016-01-01

    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

  17. 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.

  18. 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…

  19. 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.

  20. Orienteering Map and Compass: A Guide and Outline to Its Science and Practice.

    ERIC Educational Resources Information Center

    Campbell, Mel; Burton, VirLynn

    This orienteering manual is used to teach map and compass skills to elementary school students on an overnight outdoor experience administered by volunteers. Although the experience is aimed at elementary students, student teachers have the opportunity to participate as instructors. After a few words to the volunteers on maximizing learning among…

  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.

  3. 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.

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

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... addition to the magnetic compass. (c) Each tankship must have an illuminated repeater for the gyrocompass required under paragraph (b) that is at the main steering stand unless the gyrocompass is illuminated...

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

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... addition to the magnetic compass. (c) Each tankship must have an illuminated repeater for the gyrocompass required under paragraph (b) that is at the main steering stand unless the gyrocompass is illuminated...

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

    PubMed

    Reppert, S M

    2007-01-01

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

  7. Map and Compass Skills for the Secondary School (Understanding Topographic Maps, Developing Compass Skills, and Orienteering). Instructional Activities Series IA/S-18.

    ERIC Educational Resources Information Center

    Larkin, Robert P.

    This activity is one of a series of 17 teacher-developed instructional activities for geography at the secondary-grade level described in SO 009 140. The activity investigates the development of compass skills, map skills, and orienteering. It employs the educational-games approach. Given specific exercises and instructions, students become…

  8. Freely oriented portable superconducting magnet

    DOEpatents

    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 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

  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

    2014-08-06

    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.

  11. 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.

  12. 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.

  13. 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

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

    PubMed

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

    2012-07-17

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

  15. Ecophysiological consequences of non-random leaf orientation in the prairie compass plant, Silphium laciniatum.

    PubMed

    Jurik, Thomas W; Zhang, Hanzhong; Pleasants, John M

    1990-02-01

    The prairie compass plant (Silphium laciniatum L.) has vertical leaves that are characteristically oriented in a north-south plane (i.e., the flat surfaces of the lamina face east and west). We explored the consequences of this orientation by determining basic photosynthetic and water use characteristics in response to environmental factors and by determining total daily photosynthesis and water use of leaves held in different orientations. Average maximum CO2 exchange rate (CER) of leaves near Ames, IA was constant at 22 micromol m(-2) s(-1) from May through August and then declined. CER did not exhibit a distinct lightsaturation point. CER at photon flux densities near full sunlight was constant from 22 to 35°C leaf temperature but declined at higher temperatures. However, leaf temperatures rarely exceed 35°C during the growing season. There was no change in the pattern of response of CER to temperature over the growing season. We constrained leaves to face east-west (EW,=natural), to face north-south (NS), or to be horizontal (HOR) on eight days in 1986-1988. EW leaves had the highest light interception, leaf temperatures, CER, and transpiration early and late in the day, whereas HOR leaves had the highest values in the middle of the day. Integrations of CER and transpiration over the eight daytime periods showed EW and HOR leaves to have equivalent carbon gain, higher than that of NS leaves. HOR leaves had the highest daily transpiration. Daily water use efficiency (WUE, carbon gained/water lost) was always highest in EW leaves, with the HOR leaves having 16% lower WUE and NS leaves having 33% lower WUE. The natural orientation of compass plant leaves results in equivalent or higher carbon gain and in increased WUE when compared to leaves with other possible orientations; this is likely to have a selective advantage in a prairie environment.

  16. Quantum Probe and Design for a Chemical Compass with Magnetic Nanostructures

    NASA Astrophysics Data System (ADS)

    Cai, Jianming

    2011-03-01

    Magnetic fields as weak as Earth’s may affect the outcome of certain photochemical reactions that go through a radical pair intermediate. When the reaction environment is anisotropic, this phenomenon can form the basis of a chemical compass and has been proposed as a mechanism for animal magnetoreception. Here, we demonstrate how to optimize the design of a chemical compass with a much better directional sensitivity simply by a gradient field, e.g., from a magnetic nanostructure. We propose an experimental test of these predictions, and suggest design principles for a hybrid metallic-organic chemical compass. In addition to the practical interest in designing a biomimetic weak magnetic field sensor, our result shows that gradient fields can serve as powerful tools to probe spin correlations in radical pair reactions.

  17. Fractionating dead reckoning: role of the compass, odometer, logbook, and home base establishment in spatial orientation

    PubMed Central

    Martin, Megan M.; Winter, Shawn S.

    2008-01-01

    Rats use multiple sources of information to maintain spatial orientation. Although previous work has focused on rats' use of environmental cues, a growing number of studies have demonstrated that rats also use self-movement cues to organize navigation. This review examines the extent that kinematic analysis of naturally occurring behavior has provided insight into processes that mediate dead-reckoning-based navigation. This work supports a role for separate systems in processing self-movement cues that converge on the hippocampus. The compass system is involved in deriving directional information from self-movement cues; whereas, the odometer system is involved in deriving distance information from self-movement cues. The hippocampus functions similar to a logbook in that outward path unique information from the compass and odometer is used to derive the direction and distance of a path to the point at which movement was initiated. Finally, home base establishment may function to reset this system after each excursion and anchor environmental cues to self-movement cues. The combination of natural behaviors and kinematic analysis has proven to be a robust paradigm to investigate the neural basis of spatial orientation. PMID:18553065

  18. 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.

  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.

  20. 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).

  1. Spectral characteristics of edge magnetic turbulence in COMPASS-D

    NASA Astrophysics Data System (ADS)

    Han, W. E.; Thyagaraja, A.; Fielding, S. J.; Valovic, M.

    2000-02-01

    Edge fluctuation data from both COMPASS-D and calculations with the large-eddy simulation code CUTIE have been analysed with a number of techniques, revealing coherent structures which exhibit high-frequency, standing-wave oscillations; some of those observed during edge localized modes (ELMs) have an `inverse-chirp' character and these are related to a disturbance of the plasma boundary in the lower-inboard quadrant of the poloidal plane. A `precursor' mode, seen in Ohmic discharges at about 220 kHz just before large ELMs, appears to be outward ballooning in character. Although the CUTIE calculations do not yet include ELM simulations, the results seem to correspond qualitatively with those seen between ELMs or during ELM-free periods on COMPASS-D.

  2. 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)

  3. 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

  4. Using Online Active-Learning Techniques to Convey Time Compensated Sun Compass Orientation in the Eastern North American Monarch

    PubMed Central

    Green, Noah H.; McMahon, Douglas G.; Brame, Cynthia

    2016-01-01

    A common tool that animals use to navigate in a constant direction is known as “time compensated sun compass orientation.” This is a process by which animals use the position of the sun along with information from their internal circadian clocks to determine and maintain a directional heading. Many circadian scientists and educators use this process as an example of how the internal circadian clock can directly influence animal behavior. However, many students have difficulty grasping this biological process due to its multivariable nature. We have created an online module that uses the principles of active learning to facilitate student comprehension of this process. Our module contains instructional videos, practice problems and an interactive diagram. We implemented the module in an undergraduate biological clocks class at Vanderbilt University, where its use significantly improved students’ understanding of time compensated sun compass orientation as well as their ability to solve complex problems involving principles associated with this process. PMID:28101270

  5. 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.

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

    PubMed

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

    2010-04-06

    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.

  7. 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

  8. 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.

  9. A magnetic compass that might help coral reef fish larvae return to their natal reef.

    PubMed

    Bottesch, Michael; Gerlach, Gabriele; Halbach, Maurits; Bally, Andreas; Kingsford, Michael J; Mouritsen, Henrik

    2016-12-19

    Many coral reef fish larvae spend days to months in the open ocean before settlement on coral reefs [1]. Early in development, larvae have limited swimming capabilities and will therefore be greatly affected by currents. This can potentially result in dispersal distances of tens of kilometers [2]. Nevertheless, up to 60 % of surviving larvae have been shown to return to their natal reefs [2]. To home, the larvae must develop strong swimming capabilities and appropriate orientation mechanisms. Most late-stage larval reef fish can, after being passively drifted for days to weeks, swim strongly [3], and Ostorhinchus doederleini larvae have been shown to use chemotaxis to identify their natal reef once in its vicinity [2] and a sun compass for longer distance orientation [4] during the day. But how do they orient at night? Here, we show that newly settled fish caught at One Tree Island (OTI) at the Capricorn Bunker Reef Group (Great Barrier Reef) can use geomagnetic compass information to keep a south-east heading. This behavior might help them return to their natal reef in the absence of any celestial cues at night.

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

    PubMed

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

    2001-09-22

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

  11. Orientation and the Young Orienteer

    NASA Astrophysics Data System (ADS)

    Walsh, S. E.; Martland, J. R.

    Orientation within orienteering is dependent on the use of two basic strategies; that is, either a compass or Magnetic-North-based strategy, which relies on the use of one set of information; or the use of a map and landmark-based strategy which relies on the use of at least two sets of information. Walsh and found that, when given the choice, young children use the compass-based strategy when following complex potentially disorientating routes.The efficacy of these two basic orientation strategies was investigated within three different orienteering environments: (1) a familiar known environment; (2) a familiar unknown environment and (3) an unfamiliar unknown environment.Subjects, age range from 9 to 10think aloud particularly the introduction of basic skills to young performers. They support the argument that is essential to introduce the map and compass simultaneously and that relocation and orientation skills should be coached concurrently.

  12. 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.

  13. Behavioral evidence for a magnetic sense in the oriental armyworm, Mythimna separata

    PubMed Central

    Xu, Jingjing; Zhang, Yingchao; Li, Yue; Wan, Guijun; Chen, Fajun; Sword, Gregory A.; Pan, Weidong

    2017-01-01

    ABSTRACT Progress has been made in understanding the mechanisms underlying directional navigation in migratory insects, yet the magnetic compass involved has not been fully elucidated. Here we developed a flight simulation system to study the flight directionality of the migratory armyworm Mythimna separata in response to magnetic fields. Armyworm moths were exposed to either a 500 nT extreme weak magnetic field, 1.8 T strong magnetic field, or a deflecting magnetic field and subjected to tethered flight trials indoors in the dark. The moths were disoriented in the extreme weak magnetic field, with flight vectors that were more dispersed (variance=0.60) than in the geomagnetic field (variance=0.32). After exposure to a 1.8 T strong magnetic field, the mean flight vectors were shifted by about 105° in comparison with those in the geomagnetic field. In the deflecting magnetic field, the flight directions varied with the direction of the magnetic field, and also pointed to the same direction of the magnetic field. In the south-north magnetic field and the east-west field, the flight angles were determined to be 98.9° and 166.3°, respectively, and formed the included angles of 12.66° or 6.19° to the corresponding magnetic direction. The armyworm moths responded to the change of the intensity and direction of magnetic fields. Such results provide initial indications of the moth reliance on a magnetic compass. The findings support the hypothesis of a magnetic sense used for flight orientation in the armyworm Mythimna separata. PMID:28126710

  14. Can a hybrid chemical-ferromagnetic model of the avian compass explain its outstanding sensitivity to magnetic noise?

    PubMed Central

    2017-01-01

    While many properties of the magnetic compass of migratory birds are satisfactory explained within the chemical model of magnetoreception, its extreme sensitivity to radio-frequency magnetic fields remains a mystery. Apparently, this difficulty could be overcome if the magnetoreceptor model were augmented with a magnetite nanoparticle, which would amplify the magnetic field at the position of the magneto-sensitive cryptochrome molecule. However, comparison of the radio-frequency power used in the experiment with intrinsic magnetization noise of such a particle, estimated from the theory of fluctuations, shows that the required sensitivity cannot be reached with realistic parameters of iron-oxide nanocrystals. PMID:28296939

  15. 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.

  16. Domain wall orientation in magnetic nanowires.

    PubMed

    Vedmedenko, E Y; Kubetzka, A; von Bergmann, K; Pietzsch, O; Bode, M; Kirschner, J; Oepen, H P; Wiesendanger, R

    2004-02-20

    Scanning tunneling microscopy reveals that domain walls in ultrathin Fe nanowires are oriented along a certain crystallographic direction, regardless of the orientation of the wires. Monte Carlo simulations on a discrete lattice are in accordance with the experiment if the film relaxation is taken into account. We demonstrate that the wall orientation is determined by the atomic lattice and the resulting strength of an effective exchange interaction. The magnetic anisotropy and the magnetostatic energy play a minor role for the wall orientation in that system.

  17. 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

  18. 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.

  19. 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

  20. Resetting the compass: exploring the implicit messages of orientation to a community-engaged medical school

    PubMed Central

    Ellaway, Rachel; Dubé, Tim; Cooper, Gerry; Graves, Lisa

    2017-01-01

    Background Although students’ transition into medical school is a critical step in their professional journey, orientation has been relatively under-researched, particularly with regard to its intersections with schools’ social missions. This paper reports on a study looking at the implicit messages of orientation to the Northern Ontario School of Medicine’s undergraduate program. Methods An extended mixed methods study was conducted to look at different aspects of the School’s Orientation Week. The term “hidden curriculum” was used to shape inquiry, both in its broad sense of implicit educational experiences and messages and in its more specific sense of the educational messages sent by a medical school’s culture and activities. Data were collected using participant surveys, focus groups, and interviews. Transcripts and free-text survey responses were analyzed to identify underlying themes. Results Orientation Week was generally well received and was generally perceived by different stakeholders (such as students, school leaders, and community members) as a positive and necessary undertaking. However, there were points of contention and confusion that created a hidden curriculum with respect to participants’ identities, both as students and as future health professionals. Conclusion Orientation to undergraduate medical training can be successfully linked to a school’s social mission, but in doing so it can send complex and unintended messages to the participants that may be perceived quite differently based on their circumstances and expectations. PMID:28344720

  1. 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.

  2. 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

  3. A PURPOSE ORIENTED MAGNETIC SEPARATOR: SKIMMER

    SciTech Connect

    Salih Ersayin

    2005-08-09

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

  4. 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

  5. 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.

  6. 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

  7. 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.

  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. Chemical compass model of avian magnetoreception.

    PubMed

    Maeda, Kiminori; Henbest, Kevin B; Cintolesi, Filippo; Kuprov, Ilya; Rodgers, Christopher T; Liddell, Paul A; Gust, Devens; Timmel, Christiane R; Hore, P J

    2008-05-15

    Approximately 50 species, including birds, mammals, reptiles, amphibians, fish, crustaceans and insects, are known to use the Earth's magnetic field for orientation and navigation. Birds in particular have been intensively studied, but the biophysical mechanisms that underlie the avian magnetic compass are still poorly understood. One proposal, based on magnetically sensitive free radical reactions, is gaining support despite the fact that no chemical reaction in vitro has been shown to respond to magnetic fields as weak as the Earth's ( approximately 50 muT) or to be sensitive to the direction of such a field. Here we use spectroscopic observation of a carotenoid-porphyrin-fullerene model system to demonstrate that the lifetime of a photochemically formed radical pair is changed by application of < or =50 microT magnetic fields, and to measure the anisotropic chemical response that is essential for its operation as a chemical compass sensor. These experiments establish the feasibility of chemical magnetoreception and give insight into the structural and dynamic design features required for optimal detection of the direction of the Earth's magnetic field.

  10. Measurement of clottability of fibrin polymers using magnetic orientation

    NASA Astrophysics Data System (ADS)

    Iwasaka, M.; Ueno, S.; Tsuda, H.

    1996-04-01

    Fibrin polymers, as a kind of diamagnetic material, are oriented parallel to the direction of magnetic fields. We investigated the polymerization of partially digested fibrinogens in an 8 T magnetic field in order to observe the clotting ability of various sizes of fibrinogen fractions using a magnetic orientation technique. We purified high-molecular weight fraction (F1) and low-molecular weight fraction from human fibrinogen (F2). Fibrin gels were formed in an 8 T magnetic field for 9 h, and transmittancies were measured to evaluate the degree of magnetic orientation. The results show that a lack at the C-terminal half of one Aα chain did not affect the magnetic orientation of fibrin. We also investigated the effect of the digestion of fibrinogen by plasmin on the magnetic orientation of fibrin. The result shows that partially digested fibrin molecules also orient in an 8 T magnetic field. However, the degree of magnetic orientation significantly decreases when fragment X and fragment Y appear.

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

    NASA Astrophysics Data System (ADS)

    Sakhnini, Lama; Dairi, Maheen; Manaa, Hacene

    2007-09-01

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

  12. 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

  13. Optimal Coil Orientation for Transcranial Magnetic Stimulation

    PubMed Central

    Richter, Lars; Neumann, Gunnar; Oung, Stephen; Schweikard, Achim; Trillenberg, Peter

    2013-01-01

    We study the impact of coil orientation on the motor threshold (MT) and present an optimal coil orientation for stimulation of the foot. The result can be compared to results of models that predict this orientation from electrodynamic properties of the media in the skull and from orientations of cells, respectively. We used a robotized TMS system for precise coil placement and recorded motor-evoked potentials with surface electrodes on the abductor hallucis muscle of the right foot in 8 healthy control subjects. First, we performed a hot-spot search in standard (lateral) orientation and then rotated the coil in steps of 10° or 20°. At each step we estimated the MT. For navigated stimulation and for correlation with the underlying anatomy a structural MRI scan was obtained. Optimal coil orientation was 33.1±18.3° anteriorly in relation to the standard lateral orientation. In this orientation the threshold was 54±18% in units of maximum stimulator output. There was a significant difference of 8.0±5.9% between the MTs at optimal and at standard orientation. The optimal coil orientations were significantly correlated with the direction perpendicular to the postcentral gyrus (). Robotized TMS facilitates sufficiently precise coil positioning and orientation to study even small variations of the MT with coil orientation. The deviations from standard orientation are more closely matched by models based on field propagation in media than by models based on orientations of pyramidal cells. PMID:23593200

  14. Conceptualizing and experiencing compassion.

    PubMed

    Condon, Paul; Feldman Barrett, Lisa

    2013-10-01

    Does compassion feel pleasant or unpleasant? Westerners tend to categorize compassion as a pleasant or positive emotion, but laboratory compassion inductions, which present another's suffering, may elicit unpleasant feelings. Across two studies, we examined whether prototypical conceptualizations of compassion (as pleasant) differ from experiences of compassion (as unpleasant). After laboratory-based neutral or compassion inductions, participants made abstract judgments about compassion relative to various emotion-related adjectives, thereby providing a prototypical conceptualization of compassion. Participants also rated their own affective states, thereby indicating experiences of compassion. Conceptualizations of compassion were pleasant across neutral and compassion inductions. After exposure to others' suffering, however, participants felt increased levels of compassion and unpleasant affect, but not pleasant affect. After neutral inductions, participants reported more pleasant than unpleasant affect, with moderate levels of compassion. Thus, prototypical conceptualizations of compassion are pleasant, but experiences of compassion can feel pleasant or unpleasant. The implications for emotion theory in general are discussed.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. The Direction of the Neutral Hydrogen Velocity in the Inner Heliosphere as a Possible Interstellar Magnetic Field Compass

    NASA Astrophysics Data System (ADS)

    Pogorelov, Nikolai V.; Zank, Gary P.

    2006-01-01

    We discuss the physical reasons that lead to the deflection of the interstellar neutral hydrogen flow from the direction of propagation of neutral helium in the inner heliosheath. On the basis of numerical simulations, the possibilities are investigated for deriving the orientation of the interstellar magnetic field as a function of the deflection angle.

  20. 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.

  1. 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.

  2. 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

  3. 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,…

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

    PubMed

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

    2015-05-01

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

  5. 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.

  6. Experimental quantum simulation of Avian Compass in a nuclear magnetic resonance system

    NASA Astrophysics Data System (ADS)

    Pearson, Jason; Feng, GuanRu; Zheng, Chao; Long, GuiLu

    2016-12-01

    Avian magnetoreception is the capacity for avians to sense the direction of the Earth's magnetic field. Discovered more than forty years ago, it has attracted intensive studies over the years. One promising model for describing this capacity in avians is the widely used reference-and-probe model where radical pairs within the eyes of bird combines to form singlet and triplet quantum states. The yield depends on the angle between the Earth's magnetic field and the molecules' axis, hence the relative value of yield of the singlet state or triplet state enables avians to sense the direction. Here we report the experimental demonstration of avian magnetoreception in a nuclear magnetic resonance quantum information processor. It is shown clearly from the experiment that the yield of the singlet state attains maximum when it is normal to the Earth's magnetic field, and the experimental results agree with theory very well.

  7. 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, Miscellaneous Systems, and Equipment § 169.709 Compass. (a) Each vessel must be fitted with a magnetic...

  8. 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, Miscellaneous Systems, and Equipment § 169.709 Compass. (a) Each vessel must be fitted with a magnetic...

  9. Investigations of Magnetic Field Disturbances at Little Rock Air Force Base Compass Calibration Hardstand

    DTIC Science & Technology

    1990-09-01

    magnetic field disturbance. Examination of a piece of the hardstand concrete reveals that the aggregate is igneous (nepheline syenite )-with magnetite as an...nepheline syenite ) with magnetite as an accessory mineral. The permanent magnetization of the aggregate is sufficient to visibly deflect the needle...aggregate is a dark, igneous material (Figure 10). The aggregate is from a well known local quarry, and is identified as nepheline syenite , which has

  10. 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.

  11. 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...

  12. The Role of Orientation of Magnetic Fields in Contact Discontinuities

    NASA Astrophysics Data System (ADS)

    Tsai, T. C.; Hsieh, W. C.; Chao, J. K.

    2014-12-01

    Contact discontinuities are one type of the discontinuities in MHD plasma. Contact discontinuities are discontinuities with continuous magnetic fields but without plasma flows across a plasma density jump. Contact discontinuities are characterized by a remarkable plasma density jump but identical plasma bulk velocity, magnetic fields and thermal pressure on two sides of the discontinuity. Contact discontinuities are rarely observed in the nature. Due to a rapid diffusion of plasma along the continuous magnetic field lines across its surface, it is believed that contact discontinuities will rapidly broaden into a smooth transition then lose its identity. In this presentation, we study the effect of the orientation of magnetic field lines on the diffusion of plasma in contact discontinuities. With respect to the normal of a contact discontinuity, the cases of orientation of (1) parallel, (2) quasi-parallel, (3) perpendicular and (4) quasi-perpendicular magnetic fields are studied.

  13. 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…

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

    PubMed

    Cai, Jianming; Plenio, Martin B

    2013-12-06

    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.

  15. Magnetic fabrics and petrofabrics: their orientation distributions and anisotropies

    NASA Astrophysics Data System (ADS)

    Borradaile, Graham J.

    2001-10-01

    Magnetic-fabric and other petrofabric anisotropies may be described by second-rank tensors represented by ellipsoids. For a homogeneous petrofabric that is adequately sampled, a stereoplot of the orientation-distribution of the tensors' principal axes (maximum, intermediate and minimum) should show three orthogonal concentrations. The concentrations form some combination of shapes from circular clusters through partial girdles to full girdles. The concentrations' elliptical eccentricities are constrained by the symmetry of the sample-orientation-distribution (i.e. L, L>S, L=S etc.) as well as the individual sample-anisotropies. The mean orientations of principal axes must be orthogonal, just as with individual sample-tensors. This requires tensor-statistics for their calculation ( Jelinek, 1978). Furthermore, elliptical confidence cones for the means should parallel principal planes, preserving overall orthorhombic symmetry. However, in practice, sub-orthorhombic symmetry may arise from unrepresentative sampling but it may also be a useful indicator of multiple or heterogeneous petrofabrics. In the case of magnetic fabrics, the wide range in average susceptibility values and variation in magnetic mineralogy permit small numbers of high-susceptibility samples to deflect the orientation of the tensor-mean away from the majority of samples. Normalizing the samples by their bulk susceptibility overcomes this, but the orientation of high-susceptibility outliers may signify an event or subfabric of importance that we should not discard. Therefore, stereoplots of both normalized and non-normalized orientation-distributions should be compared, preferably also identifying the outliers. It is important to distinguish the shape of the orientation distribution ellipsoid from the shape of the individual magnetic fabric ellipsoids. (The qualitative L-S nomenclature is best replaced by Tj where Tj=+1=oblate; Tj=-1=prolate ( Jelinek, 1981).) Invariably, the orientation

  16. 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.

  17. 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.

  18. 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.

  19. Thomson scattering in a magnetic field. II - Arbitrary field orientation

    NASA Technical Reports Server (NTRS)

    Whitney, Barbara A.

    1991-01-01

    This paper presents solutions to the equation of transfer for Thomson scattering in a constant magnetic field of arbitrary orientation. Results from several atmospheres are combined to give the flux from a dipole star. The results are compared to the polarization data of the magnetic white dwarf Grw + 70 deg 8247. The fit is good, though it implies a very large polarization in the ultraviolet. Thomson scattering is not thought to be an important opacity source in white dwarfs, so the good fit is either fortuitous or is perhaps explained by assuming the magnetic field affects the polarization processes in all opacities similarly.

  20. 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.

  1. 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.

  2. Hard magnetization direction and its relation with magnetic permeability of highly grain-oriented electrical steel

    NASA Astrophysics Data System (ADS)

    Wang, Hao; Li, Chang-sheng; Zhu, Tao

    2014-11-01

    The magnetic properties of highly grain-oriented electrical steel vary along different directions. In order to investigate these properties, standard Epstein samples were cut at different angles to the rolling direction. The hard magnetization direction was found at an angle of 60° to the rolling direction. To compare the measured and fitting curves, when the magnetic field intensity is higher than 7000 A/m, it is appropriate to simulate the relation of magnetic permeability and magnetization angle using the conventional elliptical model. When the magnetic field intensity is less than 3000 A/m, parabolic fitting models should be used; but when the magnetic field intensity is between 3000 and 7000 A/m, hybrid models with high accuracy, as proposed in this paper, should be applied. Piecewise relation models of magnetic permeability and magnetization angle are significant for improving the accuracy of electromagnetic engineering calculations of electrical steel, and these new models could be applied in further industrial applications.

  3. Magnetic field alignment of randomly oriented, high aspect ratio silicon microwires into vertically oriented arrays.

    PubMed

    Beardslee, Joseph A; Sadtler, Bryce; Lewis, Nathan S

    2012-11-27

    External magnetic fields have been used to vertically align ensembles of silicon microwires coated with ferromagnetic nickel films. X-ray diffraction and image analysis techniques were used to quantify the degree of vertical orientation of the microwires. The degree of vertical alignment and the minimum field strength required for alignment were evaluated as a function of the wire length, coating thickness, magnetic history, and substrate surface properties. Nearly 100% of 100 μm long, 2 μm diameter, Si microwires that had been coated with 300 nm of Ni could be vertically aligned by a 300 G magnetic field. For wires ranging from 40 to 60 μm in length, as the length of the wire increased, a higher degree of alignment was observed at lower field strengths, consistent with an increase in the available magnetic torque. Microwires that had been exposed to a magnetic sweep up to 300 G remained magnetized and, therefore, aligned more readily during subsequent magnetic field alignment sweeps. Alignment of the Ni-coated Si microwires occurred at lower field strengths on hydrophilic Si substrates than on hydrophobic Si substrates. The magnetic field alignment approach provides a pathway for the directed assembly of solution-grown semiconductor wires into vertical arrays, with potential applications in solar cells as well as in other electronic devices that utilize nano- and microscale components as active elements.

  4. Modeling of particles orientation in magnetic field in drying magnetic coatings

    NASA Astrophysics Data System (ADS)

    Potanin, Andrei A.; Reynolds, George; J. Hirko, Ronald

    2000-03-01

    Filament coating is studied as a model of magnetic tape manufacturing. Freshly coated filament is driven through a solenoid magnet which orients particles. After drying the coated filament, its squareness is measured as a function of the magnet position, field and the filament speed during coating. Production and model mixes are tested, which differ in dispersion quality and drying rate. A mean-field model is used to describe orientation of particles in the coating. The model fits experiments with two parameters: particles mobility and a mean-field interaction coefficient. Well dispersed kneaded mix has higher mobility and weaker interactions than non-kneaded mixes. The model well agrees with the data for squareness decay with magnet separation from the mix deposition point, thereby providing a theoretical tool for finding proper magnet position on the production coating lines.

  5. 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.

  6. 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.

  7. 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...

  8. 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.

  9. 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.

  10. Mode II interlaminar fracture toughness of carbon fabric composite laminates with carbon nanotube oriented by magnet

    NASA Astrophysics Data System (ADS)

    Xu, Xinguang; Zhou, Zhenggang

    2017-03-01

    Inspired by the residual iron nanoparticles wrapped in the CNTs tips, we developed a method to induce efficient orientation of multiwalled CNTs bundles by relatively low magnetic fields. Laminates were fabricated to investigate the effect of magnet oriented CNTs on GIIC properties. Microstructure anisotropy of nanotube bundles demonstrated the orientation of CNT bundles by magnet. Furthermore, the application of magnet increased mode II interlaminar fracture toughness by 29% compared to plain laminates.

  11. 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.

  12. Orientation of birds in total darkness.

    PubMed

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

    2008-04-22

    Magnetic compass orientation of migratory birds is known to be light dependent, and radical-pair processes have been identified as the underlying mechanism. Here we report for the first time results of tests with European robins, Erithacus rubecula, in total darkness and, as a control, under 565 nm green light. Under green light, the robins oriented in their normal migratory direction, with southerly headings in autumn and northerly headings in spring. By contrast, in darkness they significantly preferred westerly directions in spring as well as autumn. This failure to show the normal seasonal change characterizes the orientation in total darkness as a "fixed direction" response. Tests in magnetic fields with the vertical or the horizontal component inverted showed that the preferred direction depended on the magnetic field but did not involve the avian inclination compass. A high-frequency field of 1.315 MHz did not affect the behavior, whereas local anesthesia of the upper beak resulted in disorientation. The behavior in darkness is thus fundamentally different from normal compass orientation and relies on another source of magnetic information: It does not involve the radical-pair mechanism but rather originates in the iron-containing receptors in the upper beak.

  13. 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.

  14. 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.

  15. 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.

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

    PubMed

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

    2012-02-29

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

  17. 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

  18. 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.

  19. 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.

  20. Simple and Inexpensive Classroom Demonstrations of Nuclear Magnetic Resonance and Magnetic Resonance Imaging

    NASA Astrophysics Data System (ADS)

    Olson, Joel A.; Nordell, Karen J.; Chesnik, Marla A.; Landis, Clark R.; Ellis, Arthur B.; Rzchowski, M. S.; Condren, S. Michael; Lisensky, George C.

    2000-07-01

    Several demonstrations of resonance phenomena associated with nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) are described. The demonstrations comprise common orienteering compasses, whose needles represent magnetic dipoles, along with three collinear permanent magnets and a magnetic stir plate or pulseable electromagnets. The trio of permanent magnets provides a laterally uniform magnetic field, whose strength decreases with distance from the magnets. Resonance can be observed by adjusting the frequency of the magnetic stirrer to match the resonant frequency of the compass needle, which is shown to depend on magnetic field strength, that is, the needle's position relative to the permanent magnets. Another demonstration involves pulsing electromagnets that apply a perpendicular magnetic field that causes the compass needles to oscillate. The effects of shielding, spin-spin coupling, magnetogyric ratio, and free induction decay can also be demonstrated. By moving the trio of permanent magnets relative to the compasses, the MRI experiment can be mimicked. Complete instructions for the construction of the demonstrations, which can be used on an overhead projector, are included.

  1. 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

    2014-12-12

    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.

  2. 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

  3. Love and compassion meditation: a nondual perspective.

    PubMed

    Josipovic, Zoran

    2016-06-01

    This paper discusses meditation from the unique perspective of the nondual approach and explores the possible relevance of this approach to applications of love and compassion meditation in clinical settings. It contrasts the nondual approach with the better known gradual or goal-oriented, dualistic view of meditation. This paper also introduces one of the central ideas of the nondual approach-that love and compassion, like other positive qualities that are ordinarily considered as goals of meditation practice, can be found to be already present within oneself as innate dimensions of one's authentic being.

  4. 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.

  5. 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.

  6. Bats use magnetite to detect the earth's magnetic field.

    PubMed

    Holland, Richard A; Kirschvink, Joseph L; Doak, Thomas G; Wikelski, Martin

    2008-02-27

    While the role of magnetic cues for compass orientation has been confirmed in numerous animals, the mechanism of detection is still debated. Two hypotheses have been proposed, one based on a light dependent mechanism, apparently used by birds and another based on a "compass organelle" containing the iron oxide particles magnetite (Fe(3)O(4)). Bats have recently been shown to use magnetic cues for compass orientation but the method by which they detect the Earth's magnetic field remains unknown. Here we use the classic "Kalmijn-Blakemore" pulse re-magnetization experiment, whereby the polarity of cellular magnetite is reversed. The results demonstrate that the big brown bat Eptesicus fuscus uses single domain magnetite to detect the Earths magnetic field and the response indicates a polarity based receptor. Polarity detection is a prerequisite for the use of magnetite as a compass and suggests that big brown bats use magnetite to detect the magnetic field as a compass. Our results indicate the possibility that sensory cells in bats contain freely rotating magnetite particles, which appears not to be the case in birds. It is crucial that the ultrastructure of the magnetite containing magnetoreceptors is described for our understanding of magnetoreception in animals.

  7. Maintaining compassion and preventing compassion fatigue: a practical guide.

    PubMed

    Baverstock, Anna Charlotte; Finlay, Fiona Olwen

    2016-08-01

    Compassion is innate in us as human beings. Compassion can be defined as a deep awareness of the suffering of another individual, coupled with the wish to relieve it. It has been increasingly topical, recently, in situations where an apparent breathtaking absence of compassion has allowed great harm to come to patients. So, how do we sustain compassion and prevent this loss? Central to our ability to maintain compassion is how we look after ourselves and those in our teams.

  8. 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.

  9. Conformation of sulfoquinovosyldiacylglycerol bound to a magnetically oriented membrane system.

    PubMed Central

    Howard, K P; Prestegard, J H

    1996-01-01

    The conformation of uniformly 13C-labeled sulfoquinovosyldiacylglycerol (SQDG) is studied in both membrane and solution environments using NMR spectroscopy. Analysis in a membrane-like environment is based on the measurement of dipolar interactions between 13C-13C and 1H-13C spin pairs and on the measurement of 13C chemical shift anisotropy offsets, which appear in magnetically oriented phospholipid-based membrane fragments. Potential energy maps for glycosidic torsions, phi, psi and theta 1, are calculated with a membrane interaction energy and are used in the interpretation of experimental data. The membrane-bound description for SQDG is most consistent with a set of low-energy conformations that extends the headgroup of SQDG away from the membrane surface. Analysis of the conformation of SQDG in CD3OD solution is based on measured 3JCH scalar couplings. The description of the solution conformation is modeled as a mixture of low-energy conformers predicted in the absence of a membrane interaction term and involves more extensive motional averaging than the model for SQDG embedded in the lipid matrix. Images FIGURE 1 FIGURE 6 PMID:8913595

  10. 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

  11. Compassion for simulation.

    PubMed

    Kenny, Gerard

    2016-01-01

    This topic for debate explores how simulation based education has become an area where Higher Education providers look to deliver on an agenda of recruiting, educating and assessing for compassion. This paper offers that rather than SBE being a forum for developing and promoting compassion it may actually be achieving the opposite both for those we educate and those they in turn care for. It does this through introducing two ideas, near enemies and Jung's shadow and uses these ideas to explore our understanding and expression of compassion through simulation.

  12. 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.

  13. 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.

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

    PubMed

    Holland, Richard A

    2010-11-06

    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.

  15. Magnetic-field induced orientational transition in a helicoidal liquid-crystalline antiferromagnet

    NASA Astrophysics Data System (ADS)

    Zakhlevnykh, A. N.; Kuznetsova, K. V.

    2016-11-01

    The magnetic-field induced orientational transition in helicoidal liquid-crystalline antiferromagnets representing compensated suspensions of magnetic nanoparticles in cholesteric liquid crystals is theoretically studied. The untwisting of a helicoidal structure and the behavior of mean magnetization as a function of the field strength and material parameters are investigated. It is shown that the magnetic subsystems in the field-untwisted ferronematic phase are not completely compensated, and the ferronematic phase is ferrimagnetic.

  16. Orientation magnetic phase transition induced by shock loading of the Fe-Cr-Co alloy

    NASA Astrophysics Data System (ADS)

    Sud'enkov, Yu. V.; Sarnatskii, V. M.; Smirnov, I. V.

    2017-02-01

    The strength characteristics of Fe-Cr-Co alloys have been investigated under high-strain-rate deformation of samples. It has been found that, under shock-wave loading, a significant remanent magnetization appears in the samples and their fragments due to the orientation magnetic phase transition. The threshold pressures of the magnetic phase transition have been determined, and the distribution of the remanent magnetization in the samples has been analyzed.

  17. Polarized light cues underlie compass calibration in migratory songbirds.

    PubMed

    Muheim, Rachel; Phillips, John B; Akesson, Susanne

    2006-08-11

    Migratory songbirds use the geomagnetic field, stars, the Sun, and polarized light patterns to determine their migratory direction. To prevent navigational errors, it is necessary to calibrate all of these compass systems to a common reference. We show that migratory Savannah sparrows use polarized light cues from the region of sky near the horizon to recalibrate the magnetic compass at both sunrise and sunset. We suggest that skylight polarization patterns are used to derive an absolute (i.e., geographic) directional system that provides the primary calibration reference for all of the compasses of migratory songbirds.

  18. 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.

  19. Fabrication of Tri-axially Oriented RE-Ba-Cu-O Ceramics by Magnetic Alignment

    NASA Astrophysics Data System (ADS)

    Yamaki, M.; Furuta, M.; Doi, T.; Shimoyama, J.; Horii, S.

    Magnetic alignment is a new crystal alignment process which enables tri-axial orientation without epitaxial growth at room temperature. In order to investigate the effectiveness of this magnetic tri-axial alignment process, we attempted to fabricate tri-axially oriented ErBa2Cu4O8 (Er124) ceramics by a slip-casting technique under two different modulated rotation magnetic fields (MRFs); uni-directional rotation type and oscillation type. For improvement of the degrees of tri-axial orientation in the Er124 green compacts slip-casted under MRFs, appropriate choice of sample-rotation method, magnetic field condition, control of mean diameter of source powders, and viscosity of slurry was found to be important in the case of MRFs induced by the sample-rotation. At the current stage, the degree of inplane orientation with ∼10̊ in Er124 was achieved.

  20. Two-dimensional stress—magnetization effects of grain-oriented silicon steel sheets

    NASA Astrophysics Data System (ADS)

    Saito, Akihiko; Murashige, Shinichi; Uehara, Yuji

    1994-05-01

    Changes in the magnetization vector due to tensile stress under a constant magnetic field for grain-oriented silicon-iron sheet strip samples cut at various angles from the rolling direction have been investigated. In a low magnetic field, where the magnetization is less than 1.5 T, the magnetization vector lies in the direction of the sample length and the magnetization decreases with the application of tension. Beyond that magnetic field, the magnetization vector showed a two-dimensional hysteresis loop due to the application of tension. The maximum transverse magnetization change appeared in a 10° sample, where the rotation angle of the magnetization vector was 2.5°.

  1. 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

    2014-09-09

    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.

  2. Interplanetary magnetic field orientation for transient events in the outer magnetosphere

    NASA Technical Reports Server (NTRS)

    Sibeck, D. G.; Newell, P. T.

    1995-01-01

    It is generally believed that flux transfer events (FTEs) in the outer dayside magneosphere, usually identified by transient (approximately 1 min) bipolar magneitc field perturbations in the direction normal to the nominal magnetopause, occur when the magnetosheath magetic field has a southward component. We compare the results of three methods for determining the magnetosheath magnetic field orientationat the times of previously identified UKS/IRM events: (1) the average magnetosheath magnetic field orientation in the 30-min period adjacent to the nearest magnetopause crossing, (2) the magnetosheath magnetic field orientation observed just outside the magnetopause, and (3) the lagged interplanetary magnetic field (IMF) orientation at the time of the transient events. Whereas the results of method 2 indicate that the events tend to occur for a southward magnetosheath magnetic field, the results of methods 1 and 3 show no such tnedency. The fact that the three methods yield significantly diffeent results emphasizes the need for caution in future studies.

  3. 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.

  4. Magnetic orientation of single-walled carbon nanotubes or their composites using polymer wrapping.

    PubMed

    Yonemura, Hiroaki; Yamamoto, Yuuichi; Yamada, Sunao; Fujiwara, Yoshihisa; Tanimoto, Yoshifumi

    2008-04-01

    The magnetic orientation of single-walled carbon nanotubes (SWNTs) or the SWNT composites wrapped with polymer using poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene] (MEHPPV) as the conducting polymer were examined. The formation of SWNT/MEHPPV composites was confirmed by examining absorption and fluorescence spectra. The N,N-dimethylformamide solution of SWNT/MEHPPV composites or the aqueous solution of the shortened SWNTs was introduced dropwise onto a mica or glass plate. The magnetic processing of the composites or the SWNTs was carried out using a superconducting magnet with a horizontal direction (8 T). The AFM images indicated that the SWNT/MEHPPV composites or the SWNTs were oriented randomly without magnetic processing, while with magnetic processing (8 T), they were oriented with the tube axis of the composites or the SWNTs parallel to the magnetic field. In polarized absorption spectra of SWNT/MEHPPV composites on glass plates without magnetic processing, the absorbance due to semiconducting SWNT in the near-IR region in horizontal polarized light was almost the same as that in vertical polarized light. In contrast, with magnetic processing (8 T), the absorbance due to semiconducting SWNT in the horizontal polarization direction against the direction of magnetic field was stronger than that in the vertical polarization direction. Similar results were obtained from the polarized absorption spectra for the shortened SWNTs. These results of polarized absorption spectra also support the magnetic orientation of the SWNT/MEHPPV composites or the SWNTs. On the basis of a comparison of the composites and the SWNTs alone, the magnetic orientation of SWNT/MEHPPV composites is most likely ascribable to the anisotropy in susceptibilities of SWNTs.

  5. (110) grain growth and magnetic properties of thin grain-oriented 3% silicon steel sheets

    SciTech Connect

    Nakano, Masaki; Fukunaga, Hirotoshi; Ishiyama, Kazushi; Arai, Ken Ichi

    1999-09-01

    (110) grain growth and magnetic properties in thin grain-oriented silicon sheets with ultimately low loss were investigated. A final-annealing at 1150 C for 20 min enables us to obtain the thin sheets covered with only (110) grains and consequently the magnetic induction at 800 A/m, B{sub 8} reached 1.9 T.

  6. 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.

  7. Correlation of grain growth phenomena with magnetic properties in non - oriented electrical steels

    NASA Astrophysics Data System (ADS)

    Mangiorou, E.

    2016-03-01

    This paper presents a combination of two types of method targeted to investigate the stages of the microstructure evolution in annealed non-oriented electrical steels by means of magnetic measurements and metallographic analysis. The indirect magnetic testing, carried out by Barkhausen noise was associated with the direct structural investigation by Scanning Electron Microscopy measurements. The goal of this work was to study the influence of heat transport phenomena on grain growth processes in non-oriented electrical steels, which were subjected to different annealing conditions. The results determined from the magnetic measurements and predicted from micrograph observations show a relatively good concordance.

  8. Interplanetary magnetic field orientations associated with bidirectional electron heat fluxes detected at ISEE 3

    NASA Technical Reports Server (NTRS)

    Stansberry, J. A.; Gosling, J. T.; Thomsen, M. F.; Bame, S. J.; Smith, E. J.

    1988-01-01

    A statistical survey of interplanetary magnetic field orientations associated with bidirectional electron heat fluxes observed at ISEE 3 in orbit about the Sunward Lagrange point indicates that magnetic connection of the spacecraft to the earth's shock was frequently the source of the bidirectionality. When the interplanetary magnetic field was oriented within 5 deg of the earth-spacecraft line, backstreaming electrons from the bow shock were clearly observed approximately 18 percent of the time, and connections apparently occurred for angles as large as about 30-35 deg.

  9. Preferential magnetic orientation in amorphous alloys determined by NFS and Mössbauer spectroscopy

    NASA Astrophysics Data System (ADS)

    Procházka, Vít; Vrba, Vlastimil; Šretrová, Pavla; Smrčka, David; Miglierini, Marcel

    2016-10-01

    Amorphous and nanocrystalline alloys frequently exhibit anisotropic behavior, which is a consequence of magnetic moments preferential orientation. This study reports the results obtained from a set of nuclear forward scattering experiments and transmission Mössbauer spectroscopy experiments that we have run in order to determine the degree of crystallization and the preferential orientation of magnetic moments in the material. The nuclear forward scattering of synchrotron radiation and the transmission Mössbauer spectroscopy were performed on the nanocrystalline alloy of the composition Fe79Mo8Cu1B12. The experimental data were evaluated and magnetic texture was determined. Relevance of the results was confronted with transmission Mössbauer experiments.

  10. 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.

  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. A Method for Measuring Orientation within a Magnetic Resonance Imaging Scanner using Gravity and the Static Magnetic Field (VectOrient).

    PubMed

    van Niekerk, Adam; van der Kouwe, Andre; Meintjes, Ernesta

    2017-01-25

    In MRI brain imaging, subject motion limits obtainable image clarity. Due to the hardware layout of an MRI scanner, gradient excitations can be used to rapidly detect position. Orientation, however, is more difficult to detect and is commonly calculated by comparing the position measurements of multiple spatially constrained points to a reference dataset. The result is increased size of the apparatus the subject must wear, which can influence the imaging workflow. In optical based methods marker attachment sites are limited due to the line of sight requirement between the camera and marker, and an external reference frame is introduced. To address these challenges a method called VectOrient is proposed for orientation measurement that is based on vector observations of gravity and the MRI scanner's static magnetic field. A prototype device comprising of an accelerometer, magnetometer and angular rate sensor shows good MRI compatibility. Phantom scans of a pineapple with zero scanner specific calibration achieve comparable results to a rigid body registration algorithm with deviations less than 0.8 degrees over 28 degree changes in orientation. Dynamic performance shows potential for prospective motion correction as rapid changes in orientation (peak 20 degrees per second) can be corrected. The pulse sequence implemented achieves orientation updates with a latency estimated to be less than 12.7 ms, of which only a small fraction (<1 ms) is used for computing orientation from the raw sensor signals. The device is capable of quantifying subject respiration and heart rates. The proposed approach for orientation estimation could help address some limitations of existing methods such as orientation measurement range, temporal resolution, ease of use and marker placement.

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

    PubMed

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

    2014-10-24

    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.

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

    PubMed

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

    2005-03-07

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

  15. Magnetic field orientation dependence of critical current in industrial Nb 3Sn strands

    NASA Astrophysics Data System (ADS)

    Schild, T.; Cloez, H.

    In usual superconducting devices such as magnets for NMR, the magnetic field is perpendicular to the superconducting strand axis. But in some special devices, such as magnets for the toroidal field system of fusion machines, the strands can experience any field orientation. For NbTi strands, the pinning force is dependent on the field orientation because of the drawing process (Takacs, S., Polak, M. and Krempasky, L., Critical currents of NbTi tapes with differently oriented anisotropic defects, Cryogenics, 1983, 23, 153-159). In the case of Nb 3Sn strands, the draw and react process suggests that the pinning force is isotropic. In fact, preliminary experiments have shown the contrary, which is why the magnetic field orientation dependence of the critical current for two types of industrial Nb 3Sn strands has been measured. These measurements have been performed for seven field orientations at field strengths up to 20 T. A clear anisotropic effect has been observed, which cannot be explained by Kramer's pinning law. The results are in very good agreement with an empirical law proposed in a recent study by Takayasu et al. (Takayasu, M., Montgomery, D.B. and Minervini, J.V., Effect of magnetic field direction on the critical current of twisted multifilamentary superconducting wires, Inst. of Phys. Conf. Ser., 1997, 158, 917-920). The parameters to be used in this law could be specific to the manufacturing process.

  16. Compassion and Moral Development.

    ERIC Educational Resources Information Center

    Susky, John E.

    1979-01-01

    Critiquing Skinner's and Kohlberg's moral development theories as inadequate, the author asserts that affective development (compassion, empathy, caring) is necessary to moral action. While saying that schools are limited in their ability to provide moral education, he outlines qualities of an educational environment which could facilitate moral…

  17. 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.

  18. 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…

  19. Ground magnetic response to sudden changes in the solar wind dynamic pressure and interplanetary magnetic field orientation

    NASA Astrophysics Data System (ADS)

    Sitar, Robert John

    1999-12-01

    Most, if not all, of the early research on impulsive magnetic events at high latitudes focused on first identifying the events in ground magnetic recordings and then examining the solar wind properties in search of a common link between different events. The results of these types of studies were often inconclusive and open to debate. The work presented here attacks the problem from the opposite point of view, namely by identifying changes within the solar wind and then examining the resulting ground magnetic signatures. This is accomplished using a combination of ground-based magnetic measurements from arrays of magnetometers located in Greenland and IMP 8 satellite measurements of the solar wind velocity, density, and magnetic field orientation. The study of solar wind dynamic pressure changes uses data collected by the IMP 8 satellite during 1991 and 1992 and focuses on step changes in dynamic pressure of |Dp|>2 nPa occurring on a timescale of Dt<15 min. It has been observed that the ground response does not consistently conform to existing theoretical models of field-aligned currents generated by changes in dynamic pressure. No explicit dependence on interplanetary magnetic field orientation (IMF) has been found. The relationship between IMF orientation changes and magnetic impulse events is highlighted by a case study of an IMF orientation change occurring on July 24, 1996. The effects of the IMF orientation change are observed in ground magnetometer data, incoherent scatter radar measurements, and auroral ultraviolet emissions. It is believed the ground observations result from the interaction of a hot flow anomaly with the magnetopause. These observations are the first of their kind and provide a mechanism to tie an IMF orientation change into the existing theory that traveling convection vortices result from a deformation of the magnetopause. The study of IMF orientation changes uses data from the IMP 8 satellite collected between 1992 and 1995. We have

  20. Anisotropic polymer composites synthesized by immobilizing cellulose nanocrystal suspensions specifically oriented under magnetic fields.

    PubMed

    Tatsumi, Mio; Kimura, Fumiko; Kimura, Tsunehisa; Teramoto, Yoshikuni; Nishio, Yoshiyuki

    2014-12-08

    Novel polymer composites reinforced with an oriented cellulose nanocrystal (CNC) assembly were prepared from suspensions of CNC in aqueous 2-hydroxyethyl methacrylate (HEMA) via magnetic field application to the suspensions followed by polymerization treatment. The starting suspensions used at ∼6 wt % CNC separated into an upper isotropic phase and a lower anisotropic (chiral nematic) one in the course of quiescent standing. A static or rotational magnetic field was applied to the isolated isotropic and anisotropic phases. UV-induced polymerization of HEMA perpetuated the respective states of magnetic orientation invested for the CNC dispersions to yield variously oriented CNC/poly(2-hydroxyethyl methacrylate) composites. The structural characterization was carried out by use of X-ray diffractometry and optical and scanning electron microscopy. The result indicated that CNCs were aligned in the composites distinctively according to the static or rotational magnetic application when the anisotropic phases were used, whereas such a specific CNC orientation was not appreciable when the isotropic phases were sampled. This marks out effectiveness of a coherent response of CNCs in the mesomorphic assembly. In dynamic mechanical experiments in tensile or compressive mode, we observed a clear mechanical anisotropy for the polymer composites synthesized from wholly anisotropic suspensions under static or rotational magnetization. The higher modulus (in compression) was detected for a composite reinforced by locking-in the uniaxial CNC alignment attainable through conversion of the initial chiral nematic phase into a nematic phase in the rotational magnetic field.

  1. Local Magnetic Properties in Non-oriented Electrical Steel and Their Dependence on Magnetic Easy Axis and Misorientation Parameters

    NASA Astrophysics Data System (ADS)

    Gallaugher, Matthew; Samimi, Arash; Krause, Thomas W.; Clapham, Lynann C.; Chromik, Richard R.

    2015-03-01

    An understanding of how material parameters, especially orientation and misorientation, influence the magnetic properties of non-oriented electrical steel (NOES) is important for improving the efficiency of the material in service. In this study, the local magnetic properties were measured using magnetic Barkhausen noise (MBN) on different test locations on different strips of NOES material. Local variations in magnetic properties, texture, and misorientation were revealed. A new interpretation for misorientation, called the easy axis misorientation (EAM), was created to describe the alignment of the magnetic easy axes between neighboring grains. This new EAM, visualized as a single value parameter or graphed as a distribution, was shown to be more effective at predicting the isotropic magnetic properties than previously used texture parameters based on standard orientation/misorientation definitions. It was found that a larger EAM value, especially when associated with a lower small angle EAM intensity distribution, was associated with a larger MBN energy. A larger MBN energy has been previously associated with lower losses, and therefore a greater material efficiency.

  2. 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°.

  3. 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°.

  4. 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.

  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. Improving heat generation of magnetic nanoparticles by pre-orientation of particles in a static three tesla magnetic field

    NASA Astrophysics Data System (ADS)

    Beck, Mathias M.; Lammel, Christian; Gleich, Bernhard

    2017-04-01

    Inductive heating of electrically insulating materials like fiberglass reinforced thermoplastics (FRTP) without susceptors is not possible. However, due to their low thermal conductivity a volumetric heat generation method is advisable to reach short heating times to melt this material for reshaping. This can be done with magnetic nanoparticles as susceptors within the thermoplastic of the FRTP using Néel relaxation. During the heating process the particle's magnetic moment rotates with the field while the particle itself is fixed within the thermoplastic. Therefore the heat dissipation of each particle depends on its orientation within the field. To achieve the maximum heat generation of the particles we pre-oriented the particles within a plastic at the best angle to the applied AC field for induction. To do this, five mass percent nanoparticles were dispersed in an epoxy resin, which was then hardened at room temperature in a static three Tesla magnetic field. After its solidification the heating behavior of the sample was compared to a reference sample, which was hardened without a field. The oriented particles showed an increased heating rate when oriented parallel to the applied AC field. The absorption rate was 3.3 times as high as the undirected reference sample. When the alternating electromagnetic field was perpendicular to the oriented particles, the specific absorption rate was similar to that of the reference sample. We compare this result with theory and with calculations from literature, and conduct a numerical simulation.

  8. A Simplified Quaternion-Based Algorithm for Orientation Estimation From Earth Gravity and Magnetic Field Measurements

    DTIC Science & Technology

    2008-03-01

    sensors, magnetic sen- sors, motion measurement, orientation estimation, quaternions. I. INTRODUCTION A CCURATE real- time tracking of the orientation...be determined for each of the links, then the overall posture of the human subject can accurately be rendered and communicated in real time . The...average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data

  9. Magnetic anisotropy induced by crystallographic orientation and morphological alignment in directionally-solidified eutectic Mn-Sb alloy

    NASA Astrophysics Data System (ADS)

    Lou, Chang-Sheng; Liu, Tie; Dong, Meng; Wu, Chun; Shao, Jian-Guo; Wang, Qiang

    2017-02-01

    The influences of the crystallographic orientation and morphological alignment upon the magnetic anisotropic behavior of polycrystalline materials were investigated. Microstructures obtained in eutectic Mn-Sb alloys via directional solidification simultaneously displayed crystallographic orientation and morphological alignment. Both the crystallographic orientation and the morphological alignment were able to induce magnetic anisotropy in the alloys, wherein the influence of the crystallographic orientation and the morphological alignment upon the magnetic anisotropic behavior of the alloys strongly depended upon their directions and exhibited either mutual promotion or competition. These findings may provide useful guidance for the fabrication design of functional magnetic materials.

  10. 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

  11. 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.

  12. Magnetic Barkhausen noise study of domain wall dynamics in grain-oriented 3% Si-Fe

    SciTech Connect

    Birsan, M.; Szpunar, J.A.; Krause, T.W.; Atherton, D.L.

    1996-03-01

    Magnetic Barkhausen noise measurements were performed on various samples of 3% Si steel laminates in order to clarify the relationship between the domain structure, grain orientation, and power losses. The total Barkhausen noise power has been measured versus applied field. The statistical parameters characterizing the Barkhausen noise were related to macroscopic material properties. The results obtained show that a correlation exists between the Barkhausen noise power and the total power losses. This makes it possible to connect the crystallographic structure to the magnetic behavior of grain oriented materials at both microscopic and macroscopic levels.

  13. Multiple Triangulation Analysis: another approach to determine the orientation of magnetic flux ropes

    NASA Astrophysics Data System (ADS)

    Zhou, X.-Z.; Zong, Q.-G.; Pu, Z. Y.; Fritz, T. A.; Dunlop, M. W.; Shi, Q. Q.; Wang, J.; Wei, Y.

    2006-07-01

    Another approach (Multiple Triangulation Analysis, MTA) is presented to determine the orientation of magnetic flux rope, based on 4-point measurements. A 2-D flux rope model is used to examine the accuracy of the MTA technique in a theoretical way. It is found that the precision of the estimated orientation is dependent on both the spacecraft separation and the constellation path relative to the flux rope structure. However, the MTA error range can be shown to be smaller than that of the traditional MVA technique. As an application to real Cluster data, several flux rope events on 26 January 2001 are analyzed using MTA, to obtain their orientations. The results are compared with the ones obtained by several other methods which also yield flux rope orientation. The estimated axis orientations are shown to be fairly close, suggesting the reliability of the MTA method.

  14. Filamentary probe on the COMPASS tokamak

    NASA Astrophysics Data System (ADS)

    Kovarik, K.; Duran, I.; Stockel, J.; Seidl, J.; Adamek, J.; Spolaore, M.; Vianello, N.; Hacek, P.; Hron, M.; Panek, R.

    2017-03-01

    This paper describes a new filamentary probe recently introduced on the COMPASS tokamak. It allows the measurement of electrostatic and magnetic properties of the filaments and their changes in dependence on distance from the separatrix in the region between a divertor and midplane. The probe head is mounted on a manipulator moving the probe radially on a shot-to-shot basis. This configuration is suitable for the long term statistical measurement of the plasma filaments and the measurement of their evolution during their propagation from the separatrix to the wall. The basics of the filamentary probe construction, the evolution of the plasma parameters, and first conditional averages of the plasma filaments in the scrape-off layer of the COMPASS tokamak during the L-mode regime are presented.

  15. Ac magnetorestriction hysteresis and magnetization direction in grain oriented silicon steels

    SciTech Connect

    Mogi, Hisashi; Matsuo, Yukio; Kumano, Tomoji

    1999-09-01

    A hysteresis curve of ac magnetostriction was measured, magnetizing a grain oriented silicon steel in the direction deviated from rolling direction of a sample. The ac magnetostriction ({lambda} ac) curves were analyzed as harmonics in the interest of noise spectrum of such as a power transformer. The domain structure model in this magnetostriction process was proposed. The hysteresis was large in the magnetization direction inclined at 30 and 90{degree} from the rolling direction.

  16. 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.

  17. 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.

  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. 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.

  20. 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.

  1. Orientational dependence of optically detected magnetic resonance signals in laser-driven atomic magnetometers

    NASA Astrophysics Data System (ADS)

    Colombo, Simone; Dolgovskiy, Vladimir; Scholtes, Theo; Grujić, Zoran D.; Lebedev, Victor; Weis, Antoine

    2017-01-01

    We have investigated the dependence of lock-in-demodulated M_x-magnetometer signals on the orientation of the static magnetic field B0 of interest. Magnetic resonance spectra for 2400 discrete orientations of B0 covering a 4π solid angle have been recorded by a PC-controlled steering and data acquisition system. Off-line fits by previously derived lineshape functions allow us to extract the relevant resonance parameters (shape, amplitude, width, and phase) and to represent their dependence on the orientation of B0 with respect to the laser beam propagation direction. We have performed this study for two distinct M_x-magnetometer configurations, in which the rf-field is either parallel or perpendicular to the light propagation direction. The results confirm well the algebraic theoretical model functions. We suggest that small discrepancies are related to hitherto uninvestigated atomic alignment contributions.

  2. 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.

  3. Synthesis, Magnetic Anisotropy and Optical Properties of Preferred Oriented Zinc Ferrite Nanowire Arrays

    PubMed Central

    2010-01-01

    Preferred oriented ZnFe2O4 nanowire arrays with an average diameter of 16 nm were fabricated by post-annealing of ZnFe2 nanowires within anodic aluminum oxide templates in atmosphere. Selected area electron diffraction and X-ray diffraction exhibit that the nanowires are in cubic spinel-type structure with a [110] preferred crystallite orientation. Magnetic measurement indicates that the as-prepared ZnFe2O4 nanowire arrays reveal uniaxial magnetic anisotropy, and the easy magnetization direction is parallel to the axis of nanowire. The optical properties show the ZnFe2O4 nanowire arrays give out 370–520 nm blue-violet light, and their UV absorption edge is around 700 nm. The estimated values of direct and indirect band gaps for the nanowires are 2.23 and 1.73 eV, respectively. PMID:20676211

  4. 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.

  5. 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.

  6. The geographical scale factor in orientation of migrating birds

    PubMed

    Alerstam

    1996-01-01

    Migration routes of birds throw light on orientation performance at different geographic scales, over distances ranging from a few kilometres to more than 104 km. Detailed knowledge about the flight routes may be used to test predictions about optimal orientation according to theoretical principles and about the use of compasses based on celestial or magnetic cues. Ringing recoveries demonstrate that the migratory journey of many species, such as the wheatear and willow warbler, is divided into successive legs with different main orientation. Autumn and spring migration routes are often different, sometimes diverging on a continental scale. Aerial radiotracking of whooping cranes in North America and satellite tracking of brent geese migrating from Iceland across the Greenland ice cap point to the significant role of large-scale topography for the shaping of migration routes. Compass and position control are also required, e.g. during long passages across featureless sea or ice, but how these elements are integrated into the birds' orientation system remains unclear. Radar studies from the Arctic Ocean illustrate the importance of map projections for interpreting flight paths and suggest that birds accomplish approximate great circle orientation. Gradual course changes shown by migrating knots monitored by radar in Scandinavia are at variance with expected changes if the birds were to use a star, sun or magnetic compass over longer distances. Accurate recording of short flight segments shows how flying birds respond to visual, audible and electromagnetic cues, and also documents orientation precision and capacity to integrate rapidly shifting courses into a consistent resulting orientation. Analyses of flight patterns are crucial for understanding how birds find and follow their migration routes over different ranges of geographical scale.

  7. 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…

  8. 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).

  9. 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.

  10. Orientation and open-sea navigation in sea turtles

    PubMed

    Lohmann; Lohmann

    1996-01-01

    Loggerhead sea turtle hatchlings (Caretta caretta L.) emerge from underground nests, scramble to the sea and begin a transoceanic migration by swimming away from their natal beach and into the open ocean. Evidence suggests that hatchlings sequentially use three different sets of cues to maintain orientation during their initial migration offshore. While on the beach, hatchlings find the ocean by crawling towards the lower, brighter seaward horizon and away from the dark, elevated silhouettes of vegetation and dunes. Upon entering the ocean, turtles initially orient seawards by swimming into waves, which can be detected as orbital movements from under water. Laboratory experiments have demonstrated that turtles can transfer a course initiated on the basis of waves or visual cues to a course mediated by a magnetic compass. Thus, by setting a magnetic course on the basis of nearshore cues that indicate the seaward direction, hatchlings may continue on offshore headings after entering deep water beyond sight of land. Sea turtles may use the earth's magnetic field not only as a cue for compass orientation but also as a source of world-wide positional information. Recent experiments have demonstrated that loggerheads can detect subtle differences in magnetic field inclination and intensity, two geomagnetic features that vary across the surface of the earth. Because most nesting beaches and oceanic regions are marked by a unique combination of these features, these findings raise the possibility that adult sea turtles navigate using a bicoordinate magnetic map.

  11. The effect of receiver coil orientations on the imaging performance of magnetic induction tomography

    NASA Astrophysics Data System (ADS)

    Gürsoy, D.; Scharfetter, H.

    2009-10-01

    Magnetic induction tomography is an imaging modality which aims to reconstruct the conductivity distribution of the human body. It uses magnetic induction to excite the body and an array of sensor coils to detect the perturbations in the magnetic field. Up to now, much effort has been expended with the aim of finding an efficient coil configuration to extend the dynamic range of the measured signal. However, the merits of different sensor orientations on the imaging performance have not been studied in great detail so far. Therefore, the aim of the study is to fill the void of a systematic investigation of coil orientations on the reconstruction quality of the designs. To this end, a number of alternative receiver array designs with different coil orientations were suggested and the evaluations of the designs were performed based on the singular value decomposition. A generalized class of quality measures, the subclasses of which are linked to both the spatial resolution and uncertainty measures, was used to assess the performance on the radial and axial axes of a cylindrical phantom. The detectability of local conductivity perturbations in the phantom was explored using the reconstructed images. It is possible to draw the conclusion that the proper choice of the coil orientations significantly influences the number of usable singular vectors and accordingly the stability of image reconstruction, although the effect of increased stability on the quality of the reconstructed images was not of paramount importance due to the reduced independent information content of the associated singular vectors.

  12. Orientation of diamagnetic layered transition metal oxide particles in 1-tesla magnetic fields.

    PubMed

    Sklute, Elizabeth C; Eguchi, Miharu; Henderson, Camden N; Angelone, Mark S; Yennawar, Hemant P; Mallouk, Thomas E

    2011-02-16

    The magnetic field-driven orientation of microcrystals of six diamagnetic layered transition metal oxides (HLaNb(2)O(7), HCa(2)Nb(3)O(10)·0.5H(2)O, KNaCa(2)Nb(4)O(13), KTiTaO(5), KTiNbO(5), and H(2.2)K(1.8)Nb(6)O(17)·nH(2)O) suspended in epoxy resins was studied by X-ray diffraction using permanent magnets producing a 0.8 T field. Although the degree of orientation, quantified as the Hermans order parameter, was strongly affected by the particle size distribution, in all cases microcrystals with ∼1-2 μm lateral dimensions were found to orient with the magnetic field vector in the layer plane. Control of the orientation of ionically conducting layered oxides is of interest for practical applications in batteries and fuel cells. The consistent direction of orientation of the lamellar oxides studied can be rationalized in the framework of a quantitative bond anisotropy model developed by Uyeda (Phys. Chem. Miner.1993, 20, 77-80). The asymmetry of metal-oxygen bonding at the faces of the octahedral layers results in long and short M-O bonds perpendicular to the plane of the sheets. This distortion of the M-O octahedra, which is a structural feature of almost all layered materials that contain octahedral bonding frameworks, gives rise to the diamagnetic anisotropy and results in an easy axis or plane of magnetization in the plane of the sheets.

  13. Developing Navigational Skills with Young Children: Investigating Serial and Conceptual Approaches to the Teaching of Compass Skills. Sports Science Education Programme, Annual Report 1989/90.

    ERIC Educational Resources Information Center

    Liverpool Univ. (England).

    Map and compass skills are a neglected aspect of the elementary school curriculum. Orienteering--a sport that involves running a prescribed course with the aid of map and compass--may provide an avenue for teaching these skills. This study taught orienteering to 148 10-year-old children and compared the effectiveness of a serial approach based on…

  14. 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.

  15. Orienteering in Camping.

    ERIC Educational Resources Information Center

    Larson, Elston F.

    One of the recent developments in camping is "orienteering", a program using a map and compass. Orienteering can be dovetailed into an overall camping program and used to "point up" the entire program, or it can be confined to a single simple game. The arrangement depends on the situation. The minimum age of the participants should be about 9 or…

  16. Functional magnetic resonance adaptation reveals the involvement of the dorsomedial stream in hand orientation for grasping.

    PubMed

    Monaco, Simona; Cavina-Pratesi, Cristiana; Sedda, Anna; Fattori, Patrizia; Galletti, Claudio; Culham, Jody C

    2011-11-01

    Reach-to-grasp actions require coordination of different segments of the upper limbs. Previous studies have examined the neural substrates of arm transport and hand grip components of such actions; however, a third component has been largely neglected: the orientation of the wrist and hand appropriately for the object. Here we used functional magnetic resonance imaging adaptation (fMRA) to investigate human brain areas involved in processing hand orientation during grasping movements. Participants used the dominant right hand to grasp a rod with the four fingers opposing the thumb or to reach and touch the rod with the knuckles without visual feedback. In a control condition, participants passively viewed the rod. Trials in a slow event-related design consisted of two sequential stimuli in which the rod orientation changed (requiring a change in wrist posture while grasping but not reaching or looking) or remained the same. We found reduced activation, that is, adaptation, in superior parieto-occipital cortex (SPOC) when the object was repeatedly grasped with the same orientation. In contrast, there was no adaptation when reaching or looking at an object in the same orientation, suggesting that hand orientation, rather than object orientation, was the critical factor. These results agree with recent neurophysiological research showing that a parieto-occipital area of macaque (V6A) is modulated by hand orientation during reach-to-grasp movements. We suggest that the human dorsomedial stream, like that in the macaque, plays a key role in processing hand orientation in reach-to-grasp movements.

  17. 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.

  18. 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.

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

    PubMed

    Sabatini, Angelo Maria

    2011-01-01

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

  20. 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.

  1. Effects of DC bias on magnetic performance of high grades grain-oriented silicon steels

    NASA Astrophysics Data System (ADS)

    Ma, Guang; Cheng, Ling; Lu, Licheng; Yang, Fuyao; Chen, Xin; Zhu, Chengzhi

    2017-03-01

    When high voltage direct current (HVDC) transmission adopting mono-polar ground return operation mode or unbalanced bipolar operation mode, the invasion of DC current into neutral point of alternating current (AC) transformer will cause core saturation, temperature increasing, and vibration acceleration. Based on the MPG-200D soft magnetic measurement system, the influence of DC bias on magnetic performance of 0.23 mm and 0.27 mm series (P1.7=0.70-1.05 W/kg, B8>1.89 T) grain-oriented (GO) silicon steels under condition of AC / DC hybrid excitation were systematically realized in this paper. For the high magnetic induction GO steels (core losses are the same), greater thickness can lead to stronger ability of resisting DC bias, and the reasons for it were analyzed. Finally, the magnetostriction and A-weighted magnetostriction velocity level of GO steel under DC biased magnetization were researched.

  2. 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.

  3. Homogeneous static magnetic field of different orientation induces biological changes in subacutely exposed mice.

    PubMed

    Milovanovich, Ivan D; Ćirković, Saša; De Luka, Silvio R; Djordjevich, Drago M; Ilić, Andjelija Ž; Popović, Tamara; Arsić, Aleksandra; Obradović, Danilo D; Oprić, Dejan; Ristić-Djurović, Jasna L; Trbovich, Alexander M

    2016-01-01

    It has been shown that static magnetic field (SMF) of moderate intensity produces considerable impact on biological systems. SMF can be homogeneous or inhomogeneous. In many studies, inhomogeneous SMF was employed. Aware that inhomogeneous SMF could result in experimental variability, we investigated the influence of a vertical homogeneous SMF of different orientation. Male Swiss-Webster 9- to 10-week-old mice were subacutely exposed to upward- and downward-oriented SMF of 128 mT generated by a cyclotron for 1 h/day during a 5-day period. We found that SMF affected various organs and that these effects were, to some degree, dependent on SMF orientation. Both upward- and downward-oriented SMF caused a reduction in the amount of total white blood cells (WBC) and lymphocytes in serum, a decrease of granulocytes in the spleen, kidney inflammation, and an increase in the amount of high-density lipoprotein (HDL). In addition, upward-oriented SMF caused brain edema and increased spleen cellularity. In contrast, downward-oriented SMF induced liver inflammation and a decrease in the amount of serum granulocytes. These effects might represent a specific redistribution of pro-inflammatory cells in blood and among various organs. It appears that homogeneous SMF of 128 mT affected specific organs in the body, rather than simultaneously and equally influencing the entire body system.

  4. Meson spectroscopy at COMPASS

    NASA Astrophysics Data System (ADS)

    Grube, Boris

    2016-11-01

    The goal of the COMPASS experiment at CERN is to study the structure and dynamics of hadrons. The two-stage spectrometer used by the experiment has large acceptance and covers a wide kinematic range for charged as well as neutral particles and can therefore measure a wide range of reactions. The spectroscopy of light mesons is performed with negative (mostly π-) and positive (p, π+) hadron beams with a momentum of 190 GeV/c. The light-meson spectrum is measured in different final states produced in diffractive dissociation reactions with squared four-momentum transfer t to the target between 0.1 and 1.0 (GeV=c)2. The flagship channel is the π-π-π+ final state, for which COMPASS has recorded the currently world's largest data sample. These data not only allow to measure the properties of known resonances with high precision, but also to observe new states. Among these is a new axial-vector signal, the a1(1420), with unusual properties. Novel analysis techniques have been developed to extract also the amplitude of the π-π+ subsystem as a function of 3π mass from the data. The findings are confirmed by the analysis of the π-π0π0 final state.

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

    PubMed Central

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

    2015-01-01

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

  6. A novel method for assessing the 3-D orientation accuracy of inertial/magnetic sensors.

    PubMed

    Faber, Gert S; Chang, Chien-Chi; Rizun, Peter; Dennerlein, Jack T

    2013-10-18

    A novel method for assessing the accuracy of inertial/magnetic sensors is presented. The method, referred to as the "residual matrix" method, is advantageous because it decouples the sensor's error with respect to Earth's gravity vector (attitude residual error: pitch and roll) from the sensor's error with respect to magnetic north (heading residual error), while remaining insensitive to singularity problems when the second Euler rotation is close to ±90°. As a demonstration, the accuracy of an inertial/magnetic sensor mounted to a participant's forearm was evaluated during a reaching task in a laboratory. Sensor orientation was measured internally (by the inertial/magnetic sensor) and externally using an optoelectronic measurement system with a marker cluster rigidly attached to the sensor's enclosure. Roll, pitch and heading residuals were calculated using the proposed novel method, as well as using a common orientation assessment method where the residuals are defined as the difference between the Euler angles measured by the inertial sensor and those measured by the optoelectronic system. Using the proposed residual matrix method, the roll and pitch residuals remained less than 1° and, as expected, no statistically significant difference between these two measures of attitude accuracy was found; the heading residuals were significantly larger than the attitude residuals but remained below 2°. Using the direct Euler angle comparison method, the residuals were in general larger due to singularity issues, and the expected significant difference between inertial/magnetic sensor attitude and heading accuracy was not present.

  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 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

  9. Inner Core Anisotropy Due to the Magnetic Field--induced Preferred Orientation of Iron.

    PubMed

    Karato, S

    1993-12-10

    Anisotropy of the inner core of the Earth is proposed to result from the lattice preferred orientation of anisotropic iron crystals during their solidification in the presence of a magnetic field. The resultant seismic anisotropy is related to the geometry of the magnetic field in the core. This hypothesis implies that the observed anisotropy (fast velocity along the rotation axis) indicates a strong toroidal field in the core, which supports a strong field model for the geodynamo if the inner core is made of hexagonal close-packed iron.

  10. Rotational magnetization and rotational losses of grain oriented silicon steel sheets -- fundamental aspects and theory

    SciTech Connect

    Pfuetzner, H. . Bioelectricity and Magnetism Division)

    1994-09-01

    Rotational magnetization of grain oriented SiFe sheets involves three mechanisms: anisotropy, hysteresis and eddy currents. Apart from describing the respective physical background, the paper is focused on a separation of mechanisms. It discusses dependencies between field quantities which in the dynamic case are complicated by the fact that a three-dimensional field problem arises here. It is demonstrated that within a plane inner surface of a sheet, the magnetic behavior is independent of frequency in approximation. On the other hand, eddy currents yield phase shifts between individual surfaces. Respective rotational losses and their portions are discussed on the basis of Poynting's theorem.

  11. Microstructures and magnetic properties of heatproof domain-refined grain-oriented silicon steel sheets

    SciTech Connect

    Kosuge, K.; Hirose, K.; Kuroki, K. )

    1994-12-01

    Microstructure and magnetic properties of heatproof domain-refined grain-oriented silicon steel sheets were studied. Local strains were introduced using two types of gear roll as well as cog tips, one 35 [mu]m and the other 85 [mu]m. After the local strains were introduced onto sheets, the distribution of hardness near the groove was measured. The nuclei of micrograins were investigated at various applied rolling loads. After stress-relief annealing, various shapes of micrograins and grooves were observed. The effect of these various shapes of grooves and micrograins on magnetic properties was clarified. The role of micrograins and grooves on domain refining is discussed.

  12. 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.

  13. Light-dependent magnetoreception: orientation behaviour of migratory birds under dim red light.

    PubMed

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

    2008-10-01

    Magnetic compass orientation in migratory birds has been shown to be based on radical pair processes and to require light from the short wavelength part of the spectrum up to 565 nm Green. Under dim red light of 645 nm wavelength and 1 mW m(-2) intensity, Australian silvereyes and European robins showed a westerly tendency that did not change between spring and autumn, identifying it as a 'fixed direction' response. A thorough analysis revealed that this orientation did not involve the inclination compass, but was a response based on the polarity of the magnetic field. Furthermore, in contrast to the orientation under short-wavelength light, it could be disrupted by local anaesthesia of the upper beak where iron-containing receptors are located, indicating that it is controlled by these receptors. The similarity of the response under dim red light to the response in total darkness suggests that the two responses may be identical. These findings indicate that the observed 'fixed direction' response under dim red light is fundamentally different from the normal compass orientation, which is based on radical pair processes.

  14. Preferred Orientation of Rare Earth (RE)-Doped Alumina Crystallites by an Applied Magnetic Field

    DTIC Science & Technology

    2016-06-01

    studies of ceramic particles involve some form of colloidal processing; slip-casting, gel- casting, or tape casting, which gives particles the mobility of...of alumina by colloidal filtration in a strong magnetic field and sintering. Advanced Engineering Materials. 2001;3(7):490–492. Approved for...Journal of Colloid and Interface Science. 2012;375(1):203–212. 19. Makiya A, Shouji D, Tanaka S, Uchida N, Kimura T, Uematsu K. Grain oriented

  15. Direct Experimental Observations on Concurrent Microstructure and Magnetic Property Developments in Non-Grain Oriented Electrical Steel

    NASA Astrophysics Data System (ADS)

    Shekhawat, S. K.; Basavaraj, V.; Hiwarkar, V. D.; Chakrabarty, R.; Nemade, J.; Guruprasad, P. J.; Suresh, K. G.; Doherty, R. D.; Samajdar, I.

    2014-08-01

    Non-grain oriented electrical steel, with minor in-grain orientation gradients, was subjected to interrupted tensile deformations and concurrent microtexture, magnetic property and residual stress measurements. After the upper yield point, clear signatures of mechanical stress relief were observed. Changes in orientation gradients led to annihilation of low-angle (1 to 3 deg) boundaries. Prior deformation compressive residual stresses became tensile and magnetic properties improved. Beyond an optimum true strain of 0.01, this boundary annihilation ceased, compressive stresses were generated, and magnetic properties degraded.

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

    PubMed

    Mouritsen, Henrik; Frost, Barrie J

    2002-07-23

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

  17. Strong geomagnetic activity forecast by neural networks under dominant southern orientation of the interplanetary magnetic field

    NASA Astrophysics Data System (ADS)

    Valach, Fridrich; Bochníček, Josef; Hejda, Pavel; Revallo, Miloš

    2014-02-01

    The paper deals with the relation of the southern orientation of the north-south component Bz of the interplanetary magnetic field to geomagnetic activity (GA) and subsequently a method is suggested of using the found facts to forecast potentially dangerous high GA. We have found that on a day with very high GA hourly averages of Bz with a negative sign occur at least 16 times in typical cases. Since it is very difficult to estimate the orientation of Bz in the immediate vicinity of the Earth one day or even a few days in advance, we have suggested using a neural-network model, which assumes the worse of the possibilities to forecast the danger of high GA - the dominant southern orientation of the interplanetary magnetic field. The input quantities of the proposed model were information about X-ray flares, type II and IV radio bursts as well as information about coronal mass ejections (CME). In comparing the GA forecasts with observations, we obtain values of the Hanssen-Kuiper skill score ranging from 0.463 to 0.727, which are usual values for similar forecasts of space weather. The proposed model provides forecasts of potentially dangerous high geomagnetic activity should the interplanetary CME (ICME), the originator of geomagnetic storms, hit the Earth under the most unfavorable configuration of cosmic magnetic fields. We cannot know in advance whether the unfavorable configuration is going to occur or not; we just know that it will occur with the probability of 31%.

  18. 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.

  19. 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

  20. 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.

  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. Incorporating Orienteering in School Programs.

    ERIC Educational Resources Information Center

    Bradford, Douglas

    Orienteering has been described as being "either a serious sport, or a relaxing recreation". Orienteering can be a family affair or an individual fight against the clock. In its simplest form, orienteering can be described as a cross-country run, jog, or walk on a predetermined course, using a map and a compass to find several control points on…

  3. 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…

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

    SciTech Connect

    Guan Xiaoxu

    2006-08-15

    We present oscillator strength spectra of the hydrogen Balmer {alpha} series in crossed strong magnetic and electric fields. Field strength regimes of interest ({gamma}{<=}0.02 a.u. and F{<=}1x10{sup 8} V/m) are the characteristic strengths observed on the surface of white dwarf stars. Based on the pseudospectral discretization technique, two independent methods have been developed to achieve reliable oscillator strengths in crossed fields. The effect of relative orientation between the magnetic and electric fields is clarified. Compared to the parallel configuration, we have observed that for the field strength regimes of interest, the perpendicular component of electric fields only results in a weaker coupling between the states belonging to the different subspaces of magnetic quantum numbers. This observation explains why the spectrum of oscillator strengths in crossed electric and magnetic fields with arbitrary mutual orientation shows similar behavior compared to that in parallel fields. However, a careful analysis shows that the two stronger transition lines at 5546 and 5620 A ring previously attributed to the Balmer {alpha} series are now identified to belong to the Balmer {beta} series. An effective scheme has also been suggested to calculate the bound-free opacities of hydrogen atoms in crossed fields.

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

    PubMed

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

    2001-01-01

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

  6. Bipolar magnetic materials for electrical manipulation of spin-polarization orientation.

    PubMed

    Li, Xingxing; Yang, Jinlong

    2013-10-14

    In spintronics, both the charge and spin of the electrons are exploited for information processing. Developing simple methods to manipulate and detect the carriers' spin orientation is among the key issues for spintronics applications. Electrical field has the advantage that it can be easily applied locally in contrast with a conventionally used magnetic field, thus it is more convenient and efficient. Bipolar magnetic materials, characterized by a unique electronic structure where the valence band and conduction band possess opposite spin polarization around the Fermi level, serve as a new class of materials for spintronics through which electrical control of spin-polarization direction can be realized simply by applying a gate voltage. This article reviews a range of materials that have bipolar spin polarization, including bipolar half metals and bipolar magnetic semiconductors, and their potential applications for creating, manipulating, and detecting spin-polarized carriers. These materials provide a promising future for electrically controllable spintronics devices.

  7. The magnetic structure of β-cobalt hydroxide and the effect of spin-orientation.

    PubMed

    Hunt, Diego; Garbarino, Gastón; Rodríguez-Velamazán, José Alberto; Ferrari, Valeria; Jobbagy, Matías; Scherlis, Damian A

    2016-11-09

    Synchrotron X-ray and neutron diffraction experiments at various temperatures, down to 3 K, along with ab initio calculations, are carried out to elucidate the magnetic order of layered β-cobalt-hydroxide. This combination of techniques allows for the unambiguous assignment of the magnetic structure of this material. Our results confirm that below the Néel temperature high-spin cobalt centers are ferromagnetically coupled within a layer, and antiferromagnetically coupled across layers (magnetic propagation vector k = (0,0,½)), in agreement with the indirect interpretation based on magnetic susceptibility measurements. A paramagnetic/antiferromagnetic transition is observed at around 15 K. Moreover, the thermal expansion behavior along the c-lattice direction, perpendicular to the layers, shows an inflection slightly above this temperature, at around 30 K. The neutron diffraction patterns and the non-collinear DFT+U calculations indicate that the magnetization forms an angle of about 35° with the cobalt planes. In particular, for an isolated ferromagnetic layer, the electronic structure calculations reveal sharp cusps on the potential energy surface when the spins point parallel or perpendicular to the planes, suggesting that the ferromagnetic superexchange mechanism is strongly sensitive to the orientation of the magnetic moment.

  8. Orientation dependent cantilever torque magnetometry in high magnetic fields and low lemperatures

    NASA Astrophysics Data System (ADS)

    Chaparala, M. V.

    1996-03-01

    The measurement of the magnetic torque τ, as a function of the orientation of the field with respect to the sample axes θ, is a very sensitive and direct method for measuring the anisotropy of magnetic thin films, high Tc superconductors, and other anisotropic systems. With traditional torque magnetometers the limitations of the available sample volume at cryogenic temperature has necessitated the use of a horizontal field, split coil magnets. While solenoid coil vertical field magnets provide much higher fields, the sample space limitations have excluded their use in these measurements. We have designed and built a rotator for the high field magnets at NHMFL that will accomodate the single crystal silicon cantilever magnetometer(M. Chaparala, O.H. Chung and M.J. Naughton, A.I.P. Conf. Proc. 273, 407 (1992).). With this setup we have extended the range of torque magnetometry to high magnetic fields (20T) and low temperatures (0.5K). The setup has an ultimate angular resolution of about a millidegree. I will summarize on the design and performance of this rotator/cantilever torque magnetometer combination and present the results of the the torque measurements on a Tl_2212 single crystal.

  9. 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

    2016-11-01

    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.

  10. 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.

  11. Orientation of growing crystals of Co- or Gd-containing L-threonine dehydrogenase by magnetic fields

    NASA Astrophysics Data System (ADS)

    Maki, Syou; Ishikawa, Kazuhiko; Ataka, Mitsuo

    2009-12-01

    L-Threonine dehydrogenase from Pyrococcus horikoshii (TDH) is a water-soluble metalloenzyme, the molecular structure of which has been unknown until recently. The Zn 2+ ion in the native TDH, prepared as a recombinant protein, is replaced artificially with Co 2+, Ni 2+ or Gd 3+. These samples are crystallized in homogeneous magnetic fields of 2-10 T. Half of the Co- or Gd-substituted crystals show magnetic orientation in a field of 2 T at 278 K whereas the crystals of the native TDH require a 4 T magnetic field for half orientation. The sensitivity to magnetic orientation can thus be increased by metal substitution. On the other hand, we cannot assign clear changes in the size, number, and quality of the native and metal-substituted crystals with and without the presence of the magnetic field.

  12. 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.

  13. Compassion and professional care: exploring the domain.

    PubMed

    van der Cingel, Margreet

    2009-04-01

    Compassion unites people during times of suffering and distress. Unfortunately, compassion cannot take away suffering. Why then, is compassion important for people who suffer? Nurses work in a domain where human suffering is evidently present. In order to give meaning to compassion in the domain of professional care, it is necessary to describe what compassion is. The purpose of this paper is to explore questions and contradictions in the debate on compassion related to nursing care. The paper reviews classical philosophers as well as contemporary scientists' main arguments on compassion. First, I will examine the relationship between compassion and suffering. Second, how does one recognize serious suffering? This issue raises questions about the role of imagination and the need for identification. Third, literature describes compassion as an emotion. Some philosophers consider emotions uncontrollable feelings; others see a clear rational dimension in emotions. In order to determine what compassion is, it is necessary to weigh these contradictional arguments. Fourth, I will discuss motives for compassion. Is compassion an act of altruism or egoism? In this debate Nietzsche and Schopenhauer are well-known opponents. Today, analysis of their arguments leads to some surprising conclusions. Fifth, there is the issue of fault and compassion. Can we only feel compassionate when people who suffer are not to blame for their own suffering? Such a condition faces professional caretakers with a dilemma which needs a thorough analysis if compassion is to be of use in the field of professional care. Finally, I will explore the moral meaning of compassion. Compassion, described as a concept with cognitive as well as affective dimensions, also has volitional and behavioural aspects. These aspects specifically are of importance to nursing care and further research of compassion in the nursing domain.

  14. Magnetization reversal in a preferred oriented (111) L1(0) FePt grown on a soft magnetic metallic glass for tilted magnetic recording.

    PubMed

    Wang, Yaocen; Sharma, Parmanand; Makino, Akihiro

    2012-02-22

    L1(0) FePt is an important material for the fabrication of high density perpendicular recording media, but the ultrahigh coercivity of L1(0) FePt restricts its use. Tilting of the magnetic easy axis and the introduction of a soft magnetic underlayer can solve this problem. However, high temperature processing and the requirement of epitaxial growth conditions for obtaining an L1(0) FePt phase are the main hurdles to be overcome. Here, we introduce a bilayered magnetic structure ((111) L1(0) FePt/glassy Fe(71)Nb(4)Hf(3)Y(2)B(20)/SiO(2)/Si) in which the magnetic easy axis of L1(0) FePt is tilted by ~36° from the film plane and epitaxial growth conditions are not required. The soft magnetic underlayer not only promotes the growth of L1(0) FePt with the preferred orientation but also provides an easy cost-effective micro/nanopatterning of recording bits. A detailed magnetic characterization of the bilayered structure in which the thickness of (111) L1(0) FePt with the soft magnetic Fe(71)Nb(4)Hf(3)Y(2)B(20) glassy underlayer varied from 5 to 60 nm is carried out in an effort to understand the magnetization switching mechanism. The magnetization switching behavior is almost the same for bilayered structures in which FePt layer thickness is >10 nm (greater than the domain wall thickness of FePt). For FePt film ~10 nm thick, magnetization reversal takes place in a very narrow field range. Magnetization reversal first takes place in the soft magnetic underlayer. On further increase in the reverse magnetic field, the domain wall in the soft magnetic layer compresses at the interface of the hard and soft layers. Once the domain wall energy becomes sufficiently large to overcome the nucleation energy of the domain wall in L1(0) FePt, the magnetization of the whole bilayer is reversed. This process takes place quickly because the domain walls in the hard layer do not need to move, and the formation of a narrower domain wall may not be favorable energetically. Our results

  15. 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.

  16. Variable-State-Dimension Kalman-Based Filter for Orientation Determination Using Inertial and Magnetic Sensors

    PubMed Central

    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

  17. 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.

  18. 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.

  19. Magnetism of Two-Dimensional Films of 3He on Highly Oriented Graphite

    NASA Astrophysics Data System (ADS)

    Bozler, H. M.; Zhang, Jinshan; Guo, Lei; Du, Yuliang; Gould, C. M.

    2006-09-01

    What is the effect of the structural length scale on the ordering of 3He films? NMR experiments on the magnetism of second layer 3He on Grafoil in the low field limit found ferromagnetic ordering for coverages over 20 atoms/nm2. Finite temperature phase transitions are prohibited in 2D when only Heisenberg interactions are present. However ordering of a two-dimensional magnetic film can be a result of a phase transition caused by weak anisotropy and/or dipolar interactions, or could be a less interesting manifestation of finite size effects. By replacing Grafoil with ZYX grade highly oriented graphite, we can study the magnetism of two-dimensional films with a substantially increased structural coherence length and test the importance of finite size effects. Our new experiments find a region of coverages where the second layer 3He films become ferromagnetic at temperatures above 1 mK, with no evidence for an increased suppression of the ordering due to increasing the coherence length. We show the results for the magnetism at a wide range of coverages as well as the effect of varying the magnetic field in the ferromagnetic cases. Our results support the interpretation in terms of a phase transition occurring at finite temperature.

  20. 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... perspective of the investor, the role of the Subadvisers is comparable to that of the individual...

  1. Investigating the Effects of Magnetic Variations on Inertial/Magnetic Orientation Sensors

    DTIC Science & Technology

    2007-09-01

    constantly present and can include common items such as computer monitors , fluorescent lighting, and powered-up elec- trical wiring inside walls. Table 1...magnetic interference are constantly present and can include common items such as computer monitors , fluorescent lighting, and powered-up electrical...data was moved it came within close proximity to numerous pieces of lab equipment simultaneously. The equip- ment included computer monitors , printers

  2. Electric and Magnetic Field Detection in Elasmobranch Fishes

    NASA Astrophysics Data System (ADS)

    Kalmijn, Ad. J.

    1982-11-01

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

  3. 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.

  4. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2007-05-01

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

  6. 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.

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

    PubMed

    Homberg, Uwe

    2004-05-01

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

  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. Effect of magnetic properties of non-oriented electrical steel on torque characteristics of interior-permanent-magnet synchronous motor

    NASA Astrophysics Data System (ADS)

    Fujimura, Hiroshi; Nitomi, Hirokatsu; Yashiki, Hiroyoshi

    The torque characteristics of interior-permanent-magnet synchronous motor (IPMSM), in which core materials were our conventional non-oriented electrical steel 35SX250 and our developed steels 35SXH, 27SXH with high permeability, were measured by a pulse wave modulation (PWM) inverter control. The torque characteristics of the motor with developed steels were superior to that of conventional steel. The advantage of developed steels was remarkable in the high-toque region. Experimental torque separation using current phase control showed that reluctance torque was strongly affected by the magnetic properties of core materials. And we did magnetic field analysis of the motors by finite element method (FEM). The flux density in the teeth of the stator core was higher in the high permeability steels than that in the conventional steel under the same current condition. The developed steels are expected to be suited to the stator material of IPMSM used as drive motors for electric vehicles and compressor motors for air conditioner.

  10. 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…

  11. 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…

  12. 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…

  13. 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…

  14. 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.

  15. 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

  16. 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

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

    PubMed Central

    Sabatini, Angelo Maria

    2011-01-01

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

  18. Systematic parameter study of a nonlinear electromagnetic energy harvester with matched magnetic orientation: Numerical simulation and experimental investigation

    NASA Astrophysics Data System (ADS)

    Deng, Wei; Wang, Ya

    2017-02-01

    This paper reports the systematic parameter study of a tristable nonlinear electromagnetic energy harvester for ambient low-frequency vibration. Numerical simulations and experimental investigations are performed on the harvester which consists of a cantilever beam, a tip coil, two tip magnets and two external side magnets. The external side magnets are deployed symmetrically along a concave surface parallel to the trajectory of the cantilever tip with a controllable distance so that the magnetic orientation of the tip magnets are matched with that of the side magnets. Therefore, instead of the ternary position parameters (d, h, α), a binary parameters pair (d0, d) is used to characterize the position of the side magnets and the performance of the energy harvester. The magnetic force and magnetic field on the cantilever tip therefore depend on the relative distance in the tip displacement direction between the tip magnets and side magnets, but is independent of the position of the side magnets on the concave surface. The magnetic force (field)-distance relationship is measured experimentally and curve fitted to obtain explicit expressions, in order to characterize the magnetic force (field) when the side magnets are placed at varied positions along the concave surface. Numerical simulation is, then, performed to predict the electromagnetic voltage output and the bandwidth of the energy harvester. The simulation results coincided with the measured data. Significant broadband response is obtained experimentally and the maximum RMS power output is 40.2 mW at 0.45g of excitation. The proposed structure showcasing the matched magnetic orientation is characterized by the binary parameters pair (d0, d) and the systematic parametric approach could contribute to the design and study of nonlinear broadband energy harvesters.

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

    PubMed

    Sandberg; BACkman; Ottosson

    1998-05-21

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

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

    NASA Astrophysics Data System (ADS)

    Ueno, S.; Matsuda, T.

    1991-04-01

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

  1. Phase alignment and crystal orientation of Al 3Ni in Al-Ni alloy by imposition of a uniform high magnetic field

    NASA Astrophysics Data System (ADS)

    Wang, Chunjiang; Wang, Qiang; Wang, Zhongying; Li, Hutian; Nakajima, Keiji; He, Jicheng

    2008-03-01

    Solidification experiments of aluminum-nickel binary alloys under uniform high magnetic fields have been conducted. The effects of high magnetic fields on the crystal orientation of Al 3Ni were investigated by XRD and the alignment of primary phases Al 3Ni were also analyzed. Experimental results showed that the easy magnetization axis of Al 3Ni crystal oriented parallel to the imposed magnetic fields and the primary phase Al 3Ni aligned perpendicular to the magnetic fields. Magnetic orientation of crystal was determined by magnetic anisotropy energy. Whereas the phase alignment should be contributed to the combined effects of magnetic orientation, crystal growth and the effects of magnetic fields on mass transport during solidification.

  2. Measurements for spin inversion and noninversion in successive decays via nuclear magnetic resonance on oriented nuclei

    SciTech Connect

    Ohya, S.; Ohtsubo, T.; Komatsuzaki, K.; Cho, D.J.; Muto, S.

    1996-09-01

    Nuclear magnetic resonance on oriented nuclei (NMR-ON) measurements were performed on the successive decays of {sup 89}Zr-{sup 89}Y{sup {ital m}} and {sup 191}Os-{sup 191}Ir{sup {ital m}} in Fe. The NMR-ON spectra of {sup 89}Zr{ital Fe} and {sup 191}Os{ital Fe} were obtained by detecting {gamma} rays from the decay of the isomers, {sup 89}Y{sup m} and {sup 191}Ir{sup m}, respectively. For {sup 89}Zr{ital Fe}, the anisotropy of the {gamma} ray increased at the resonance. On the other hand, for {sup 191}Os{ital Fe} the anisotropy of the {gamma} ray decreased at the resonance. These phenomena were explained using the spin inversion and spin noninversion processes including the lifetimes of the isomers and spin lattice relaxation times. NMR-ON measurements for such spin inversion and noninversion processes were reported. The resonance spectra were also observed by detecting {beta} rays from {sup 89}Zr and {sup 191}Os. In these experiments the magnetic moments of {sup 89}Zr and {sup 191}Os were determined to be {minus}1.08 (2) {mu}{sub N} and 0.962 (28) {mu}{sub N}, respectively. The signs of the magnetic moments of {sup 89}Y{sup m} and {sup 191}Ir{sup m} were also determined to be positive. {copyright} {ital 1996 The American Physical Society.}

  3. Dayside magnetopause transients correlated with changes of the magnetosheath magnetic field orientation

    NASA Astrophysics Data System (ADS)

    Tkachenko, O.; Šafránková, J.; Němeček, Z.; Sibeck, D. G.

    2011-04-01

    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.

  4. 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.

  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. 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…

  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. Relaxation Phenomena of a Magnetic Nanoparticle Assembly with Randomly Oriented Anisotropy

    NASA Astrophysics Data System (ADS)

    Fang; WenXiao; He; ZhenHui; Chen; DiHu; En; YunFei; Kong; XueDong

    2011-03-01

    The effects of a randomly oriented anisotropy on relaxation phenomena including the memory effect of a noninteracting magnetic nanoparticle assembly, are numerically studied with a localized partition function and a master equation, leading to the following results. During the zero-field-cooled (ZFC) process, the energy barrier histogram changes with temperature, while during the field-cooled (FC) process it remains stable. In the relaxation process after ZFC initialization, the effective energy barrier distribution, which is derived from the Tln (t/τ0) (T temperature, t time, and τ0 characteristic time constant) scaling curve, only reflects the low-energy region of the energy barrier histogram. The memory effect with temporary cooling during time evolution occurs in the studied assembly even without volume distribution and particle interaction involved.

  9. Asymptotic study of a complete magnetic attitude control cycle providing a single-axis orientation

    NASA Astrophysics Data System (ADS)

    Ovchinnikov, M. Yu.; Roldugin, D. S.; Penkov, V. I.

    2012-08-01

    The angular motion of an axisymmetrical satellite equipped with the active magnetic attitude control system is examined. Attitude control system has to ensure necessary orientation of the axis of symmetry in the inertial space. It implements the following strategy: coarse reorientation of the axis of symmetry with nutation damping or "-Bdot" without initial detumbling; spinning-up about the axis of symmetry to achieve the property of a gyro; fine reorientation of the axis in the inertial space. Dynamics of the satellite is analytically studied using averaging technique on the complete control loop consisting of five algorithms. Solutions of the equations of motion are obtained in terms of quadratures for most cases or even in closed-form. The latter allowed to study the dependence of motion parameters including time-response with respect to the orbit inclination and other parameters for all algorithms.

  10. Raman spectra and magnetization of all-ferromagnetic superlattices grown on (110) oriented SrTiO{sub 3}

    SciTech Connect

    Behera, B. C.; Ravindra, A. V.; Padhan, P.; Prellier, W.

    2014-03-03

    Superlattices consist of two ferromagnets La{sub 0.7}Sr{sub 0.3}MnO{sub 3} (LSMO) and SrRuO{sub 3} (SRO) were grown in (110)-orientation on SrTiO{sub 3} (STO) substrates. The x-ray diffraction and Raman spectra of these superlattices show the presence of in-plane compressive strain and orthorhombic structure of less than 4 u.c. thick LSMO spacer, respectively. Magnetic measurements reveal several features including reduced magnetization, enhanced coercivity, antiferromagnetic coupling, and switching from antiferromagnetic to ferromagnetic coupling with magnetic field orientations. These magnetic properties are explained by the observed orthorhombic structure of spacer LSMO in Raman scattering which occurs due to the modification in the stereochemistry of Mn at the interfaces of SRO and LSMO.

  11. Bats respond to polarity of a magnetic field.

    PubMed

    Wang, Yinan; Pan, Yongxin; Parsons, Stuart; Walker, Michael; Zhang, Shuyi

    2007-11-22

    Bats have been shown to use information from the Earth's magnetic field during orientation. However, the mechanism underlying this ability remains unknown. In this study we investigated whether bats possess a polarity- or inclination-based compass that could be used in orientation. We monitored the hanging position of adult Nyctalus plancyi in the laboratory in the presence of an induced magnetic field of twice Earth-strength. When under the influence of a normally aligned induced field the bats showed a significant preference for hanging at the northern end of their roosting basket. When the vertical component of the field was reversed, the bats remained at the northern end of the basket. However, when the horizontal component of the field was reversed, the bats changed their positions and hung at the southern end of the basket. Based on these results, we conclude that N. plancyi, unlike all other non-mammalian vertebrates tested to date, uses a polarity-based compass during orientation in the roost, and that the same compass is also likely to underlie bats' long-distance navigation abilities.

  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. Orienteering: A Swedish Way of Life.

    ERIC Educational Resources Information Center

    Oliver, Rick

    1984-01-01

    Orienteering involves navigating over an unfamiliar route with a map and a compass and locating control markers as quickly as possible. Originating in Sweden, orienting began primarily as a military event and has grown into "a sport for all." Suggested activities in orienteering to conduct in school conclude the article. (ERB)

  14. 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.

  15. Countering compassion fatigue: a requisite nursing agenda.

    PubMed

    Boyle, Deborah A

    2011-01-31

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

  16. 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.

  17. ELM structure in the boundary plasma on COMPASS-D

    NASA Astrophysics Data System (ADS)

    Fielding, S. J.; Axon, K. B.; Booth, M. G.; Buttery, R. J.; Dowling, J.; Gates, D.; Hunt, C.; Silva, C.; Valovic, M.

    1997-02-01

    ELM experimental analysis on COMPASS-D, which has previously catalogued magnetic precursor behaviour, has been extended to consider effects in the SOL. ELM precursors are observed at the divertor. Profile changes are measured with high resolution and power and particle losses in ELMs are estimated. High speed videos of an ELM show a turbulent edge extending to the outboard limiter, in broad agreement with reciprocating probe observations. A model which describes well the magnetic features of the ELM, is being extended to include predictions of power deposition structure at the divertor target, for comparison with experimental data.

  18. Magnetic domain structure, crystal orientation, and magnetostriction of Tb0.27Dy0.73Fe1.95 solidified in various high magnetic fields

    NASA Astrophysics Data System (ADS)

    Gao, Pengfei; Liu, Tie; Dong, Meng; Yuan, Yi; Wang, Qiang

    2016-03-01

    In this paper, we studied how applying a high magnetic field during solidification of Tb0.27Dy0.73Fe1.95 alloys affected their magnetic domain structure, crystal orientation, and magnetostriction. We observed the morphology of the magnetic domain during solidification, finding it change with the applied field: from fiber like (0 T) to dot like and closure mixed (4.4 T) to fiber like (8.8 T) to fishbone like (11.5 T). The alloy solidified at 4.4 T showed the best contrast of light and dark in its domain image, widest magnetic domain, fastest magnetization, and highest magnetostriction; this alloy is followed in descending order by the alloys solidified at 11.5 T, 8.8 T, and 0 T. The orientation of the (Tb, Dy)Fe2 phase changed with magnetic field from random (0 T) to <111> (4.4 T) to <113> (8.8 T) to <110> (11.5 T). The improvement in magnetostriction was likely caused by modification of both the magnetization process and the alloy microstructure.

  19. 27 T ultra-high static magnetic field changes orientation and morphology of mitotic spindles in human cells

    PubMed Central

    Zhang, Lei; Hou, Yubin; Li, Zhiyuan; Ji, Xinmiao; Wang, Ze; Wang, Huizhen; Tian, Xiaofei; Yu, Fazhi; Yang, Zhenye; Pi, Li; Mitchison, Timothy J; Lu, Qingyou; Zhang, Xin

    2017-01-01

    Purified microtubules have been shown to align along the static magnetic field (SMF) in vitro because of their diamagnetic anisotropy. However, whether mitotic spindle in cells can be aligned by magnetic field has not been experimentally proved. In particular, the biological effects of SMF of above 20 T (Tesla) have never been reported. Here we found that in both CNE-2Z and RPE1 human cells spindle orients in 27 T SMF. The direction of spindle alignment depended on the extent to which chromosomes were aligned to form a planar metaphase plate. Our results show that the magnetic torque acts on both microtubules and chromosomes, and the preferred direction of spindle alignment relative to the field depends more on chromosome alignment than microtubules. In addition, spindle morphology was also perturbed by 27 T SMF. This is the first reported study that investigated the cellular responses to ultra-high magnetic field of above 20 T. Our study not only found that ultra-high magnetic field can change the orientation and morphology of mitotic spindles, but also provided a tool to probe the role of spindle orientation and perturbation in developmental and cancer biology. DOI: http://dx.doi.org/10.7554/eLife.22911.001 PMID:28244368

  20. Orientational dynamics of ferrofluids with finite magnetic anisotropy of the particles: relaxation of magneto-birefringence in crossed fields.

    PubMed

    Raikher, Yu L; Stepanov, V I; Bacri, J-C; Perzynski, R

    2002-08-01

    Dynamic birefringence in a ferrofluid subjected to crossed bias (constant) and probing (pulse or ac) fields is considered, assuming that the nanoparticles have finite magnetic anisotropy. This is done on the basis of the general Fokker-Planck equation that takes into account both internal magnetic and external mechanical degrees of freedom of the particle. We describe the orientation dynamics in terms of the integral relaxation time of the macroscopic orientation order parameter. To account for an arbitrary relation between the bias (external) and anisotropy (internal) fields, an interpolation expression for the integral relaxation time is proposed and justified. A developed description is used to interpret the measurements of birefringence relaxation in magnetic fluids with nanoparticles of high (cobalt ferrite) and low (maghemite) anisotropy. The proposed theory appears to be in full qualitative agreement with all the experimental data available.

  1. Tunable in-plane spin orientation in Fe/Si (557) film by step-induced competing magnetic anisotropies

    NASA Astrophysics Data System (ADS)

    Tang, Jin; He, Wei; Zhang, Yong-Sheng; Li, Yan; Zhang, Wei; Sheraz Ahmad, Syed; Zhang, Xiang-Qun; Cheng, Zhao-Hua

    2016-12-01

    Although the spin-reorientation transition from out-of-plane to in-plane in Fe/Si film is widely reported, the tuning of in-plane spin orientation is not yet well developed. Here, we report the thickness-, temperature- and Cu-adsorption- induced in-plane spin-reorientation transition processes in Fe/Si (557) film, which can be attributed to the coexistence of two competing step-induced uniaxial magnetic anisotropies, i.e., surface magnetic anisotropy with magnetization easy axis perpendicular to the step and volume magnetic anisotropy with magnetization easy axis parallel to the step. For Fe film thickness smaller than 32 monolayer (ML), the magnitudes of two effects under various temperatures are extracted from the thickness dependence of uniaxial magnetic anisotropy. For Fe film thickness larger than 32 ML, the deviation of experimental results from fitting results is understood by the strain-relief-induced reduction of volume magnetic anisotropy. Additionally, the surface and volume magnetic anisotropies are both greatly reduced after covering Cu capping layer on Fe/Si (557) film while no significant influence of NaCl capping layer on step-induced magnetic anisotropies is observed. The experimental results reported here provide various practical methods for manipulating in-plane spin orientation of Fe/Si films and improve the understanding of step-induced magnetic anisotropies. Project supported by the National Basic Research Program of China (Grant Nos. 2015CB921403 and 2016YFA0300701) and the National Natural Sciences Foundation of China (Grant Nos. 51427801, 11374350, 11274360, and 11274361).

  2. Magnetic gold nanoparticles in SERS-based sandwich immunoassay for antigen detection by well oriented antibodies.

    PubMed

    Baniukevic, Julija; Hakki Boyaci, Ismail; Goktug Bozkurt, Akif; Tamer, Ugur; Ramanavicius, Arunas; Ramanaviciene, Almira

    2013-05-15

    The aim of the study was to develop an indirect, robust and simple in application method for the detection of bovine leukemia virus antigen gp51. Surface-enhanced Raman scattering (SERS) was applied as detection method. Magnetic gold nanoparticles (MNP-Au) modified by antibodies in oriented or random manner were used for the binding of gp51. The high performance liquid chromatography analysis indicated that the best antibody immobilization and antigen capturing efficiency was achieved using fragmented antibodies obtained after reduction of intact antibodies with dithiothreitol. In order to increase efficiency and sensitivity of immunoassay Raman labels consisting of gold nanorods coated by 5-thio-nitrobenzoic acid layer with covalently bounded antibodies have been constructed. The LOD and LOQ of the proposed immunoassay for antigen gp51 detection were found to be 0.95μgmL(-1) and 3.14μgmL(-1), respectively. This immunoassay was successfully applied for the detection of gp51 in milk samples in a rapid, reliable and selective manner. We believe that the proposed SERS-based immunoassay format can be applied for the detection of other proteins.

  3. 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

  4. 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,…

  5. 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.

  6. Orienteering: A Thinging Man's Sport or It's Not Nice to Fool Mother Nature

    ERIC Educational Resources Information Center

    August, Irwin

    1974-01-01

    Orienteering is land navigation through unknown countryside with map and compass. This article describes an orienteering program in the Action Education Curriculum, State University of New York, College at Purchase. (KM)

  7. 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.

  8. 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.

  9. Never Too Young to Orienteer.

    ERIC Educational Resources Information Center

    Lavine, Carolyn

    1992-01-01

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

  10. Hematological parameters' changes in mice subchronically exposed to static magnetic fields of different orientations.

    PubMed

    Djordjevich, Drago M; De Luka, Silvio R; Milovanovich, Ivan D; Janković, Saša; Stefanović, Srdjan; Vesković-Moračanin, Slavica; Cirković, Saša; Ilić, Andjelija Ž; Ristić-Djurović, Jasna L; Trbovich, Alexander M

    2012-07-01

    Static magnetic fields (SMFs) are time independent fields whose intensity can be spatially dependent. This study investigates influence of subchronic continuous exposure to upward and downward directed SMF on hematological parameters and spleen cellularity in mice. The experiment is performed on the Northern hemisphere; consequently, the vertical component of geomagnetic field is directed downward. Male, Swiss-Webster, 6 weeks old mice were exposed to the vertically declining SMF. Mice were divided in three groups and continuously exposed or not exposed for 28 days to the SMF characterized by the averaged field of 16 mT and averaged field gradient of 10 mT/cm. Differently oriented SMF did not alter hemoglobin and hematocrit content among the groups. However, the groups exposed to the upward and downward fields had statistically significant higher levels of serum transferrin compared to the control. Moreover, spleen cellularity in animals in the downward group was significantly higher compared to the upward and control group. In addition, spleen lymphocytes in both of the exposed groups were significantly higher than in the control group. In contrast, spleen granulocytes in the exposed groups were significantly lower than in the control group. Significant decrease was also observed in brain and liver iron content with concomitant increase of iron in serum and spleen in exposed animals. Subchronic continuous exposure to 16 mT SMF caused lymphocyte and granulocyte redistribution between spleen and blood. This distribution is typical for stress induced hematological changes. These results suggest that observed changes were not due to an unspecific stress response, but that they were rather caused by specific adaptation to subchronic SMF exposure.

  11. Roe v. Wade. Reflective compassion.

    PubMed

    Padovano, A T

    1998-01-01

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

  12. 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.

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

    PubMed

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

    2015-05-27

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

  14. Moon and sun compasses in sandhoppers rely on two separate chronometric mechanisms

    PubMed Central

    Ugolini, A.; Melis, C.; Innocenti, R.; Tiribilli, B.; Castellini, C.

    1999-01-01

    The relationship between the chronometric system of compensation for the apparent movement of the sun and that for the moon has been the subject of several, never proven, hypotheses. Our studies on sandhoppers have demonstrated that the chronometric mechanism of the moon compass is separate from that of the sun compass. They show (i) that a period of seven days in constant darkness has no influence on the capacity for orientation, either solar or lunar, and indicates the presence of one or more continuously operating timing mechanisms; (ii) that two different shifts in the light–dark phase have no effect on the chronometric mechanism of lunar orientation, but they do affect that of solar orientation; and (iii) that exposure to an artificial moon delayed by seven days with respect to the natural cycle causes the expected change in the mean direction of individuals tested under the natural moon, but not of those tested under the sun.

  15. The two-dimensional magnetic change process of grain-oriented silicon steel under tensile stress

    NASA Astrophysics Data System (ADS)

    Saito, Akihiko; Nakata, Kumi; Murashige, Shinichi

    1996-07-01

    The effect of tensile stress on the magnetization properties of silicon steel samples declined from the rolling direction has been investigated. The locus for the two-dimensional magnetization change was measured. The locus of magnetization due to magnetic field without stress was different from that under tension. The locus of magnetization with tension has two knees which correspond to the two knees of the hysteresis curve with tension. These results indicate the essential importance of investigations of the two-dimensional magnetization process.

  16. The effect of cold-rolling on the magnetic properties of non-oriented silicon steel sheets

    SciTech Connect

    Huang, B.Y.; Yamamoto, K.; Kaido, C.; Yamashiro, Y.

    1999-09-01

    Non-oriented 3% silicon steel sheets were cold-rolled to 0.1 mm thick by various methods, and then they were finally annealed in an argon atmosphere for 1.5 hours at 900 C with a cooling rate of 0.025 C/s. Their magnetic properties changed depending on cold-rolling method used. A sample which had magnetic two-easy-directions with strong (100) cubic texture was obtained in the following way. The sample was alternately cold-rolled in two perpendicular directions L and T, and was also subjected to an intermediate anneal. The average grain diameter of the sample was 57 {micro}m. Its magnetic induction at 800 A/m was 1.65 T in the L direction, and 1.62 T in T direction, respectively.

  17. 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.

  18. 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.

    2016-12-01

    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.

  19. 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.

  20. Structural studies of A-form sodium deoxyribonucleic acid: phosphorus-31 nuclear magnetic resonance of oriented fibers.

    PubMed

    Nall, B T; Rothwell, W P; Waugh, J S; Rupprecht, A

    1981-03-31

    A highly oriented sample of A-form sodium deoxyribonucleic acid (DNA) has been investigated by using proton-enhanced 31P nuclear magnetic resonance (NMR). Proton-decoupled spectra taken with different angles between the magnetic field direction and the fiber direction are compared to theoretical spectra which are calculated by assuming the following: (1) the orientation of the phosphate groups in the fiber is given by the A-form DNA coordinates suggested by Arnott & Hukins [Arnott, S., & Hukins, D. W. L. (1972) Biochem. Biophys. Res. Commun. 47, 1504-1509]; (2) the DNA phosphate groups may be considered stationary on the NMR time scale; (3) the relevant features of the spectra are determined solely by chemical shift anisotropy of the phosphorus atoms. The experimental and calculated spectra are in excellent agreement and support the validity of the above assumptions contrary to conclusions drawn in another investigation [Shindo, H., Wooton, J. B., Pheiffer, B. H., & Zimmerman, S. B. (1980) Biochemistry 19, 518-526]. In particular, we find no evidence to support the notion of a highly irregular phosphodiester backbone. Comparison of observed and simulated spectra allows the determination of the orientation of the 31P chemical shielding tensor relative to the bonding framework of the phosphodiester group. The orientation agrees with that expected from NMR studies of phosphodiester model compounds [Kohler, S. J., & Klein, M. P. (1976) Biochemistry 15, 967-973; Herzfeld, J., Griffin, R. G., & Haberkorn, R. A. (1978) Biochemistry 17, 2711-2718] and X-ray diffraction of oriented fibers [Arnott, S., & Hukins, D. W. L. (1972) Biochem. Biophys. Res. Commun. 47, 1504-1509].

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

    PubMed

    Coetzee, Siedine Knobloch; Klopper, Hester C

    2010-06-01

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

  2. Effects of Orientation and Anisometry of Magnetic Resonance Imaging Acquisitions on Diffusion Tensor Imaging and Structural Connectomes

    PubMed Central

    Muñoz-Moreno, Emma; López-Gil, Xavier; Soria, Guadalupe

    2017-01-01

    Diffusion-weighted imaging (DWI) quantifies water molecule diffusion within tissues and is becoming an increasingly used technique. However, it is very challenging as correct quantification depends on many different factors, ranging from acquisition parameters to a long pipeline of image processing. In this work, we investigated the influence of voxel geometry on diffusion analysis, comparing different acquisition orientations as well as isometric and anisometric voxels. Diffusion-weighted images of one rat brain were acquired with four different voxel geometries (one isometric and three anisometric in different directions) and three different encoding orientations (coronal, axial and sagittal). Diffusion tensor scalar measurements, tractography and the brain structural connectome were analyzed for each of the 12 acquisitions. The acquisition direction with respect to the main magnetic field orientation affected the diffusion results. When the acquisition slice-encoding direction was not aligned with the main magnetic field, there were more artifacts and a lower signal-to-noise ratio that led to less anisotropic tensors (lower fractional anisotropic values), producing poorer quality results. The use of anisometric voxels generated statistically significant differences in the values of diffusion metrics in specific regions. It also elicited differences in tract reconstruction and in different graph metric values describing the brain networks. Our results highlight the importance of taking into account the geometric aspects of acquisitions, especially when comparing diffusion data acquired using different geometries. PMID:28118397

  3. Effects of Orientation and Anisometry of Magnetic Resonance Imaging Acquisitions on Diffusion Tensor Imaging and Structural Connectomes.

    PubMed

    Tudela, Raúl; Muñoz-Moreno, Emma; López-Gil, Xavier; Soria, Guadalupe

    2017-01-01

    Diffusion-weighted imaging (DWI) quantifies water molecule diffusion within tissues and is becoming an increasingly used technique. However, it is very challenging as correct quantification depends on many different factors, ranging from acquisition parameters to a long pipeline of image processing. In this work, we investigated the influence of voxel geometry on diffusion analysis, comparing different acquisition orientations as well as isometric and anisometric voxels. Diffusion-weighted images of one rat brain were acquired with four different voxel geometries (one isometric and three anisometric in different directions) and three different encoding orientations (coronal, axial and sagittal). Diffusion tensor scalar measurements, tractography and the brain structural connectome were analyzed for each of the 12 acquisitions. The acquisition direction with respect to the main magnetic field orientation affected the diffusion results. When the acquisition slice-encoding direction was not aligned with the main magnetic field, there were more artifacts and a lower signal-to-noise ratio that led to less anisotropic tensors (lower fractional anisotropic values), producing poorer quality results. The use of anisometric voxels generated statistically significant differences in the values of diffusion metrics in specific regions. It also elicited differences in tract reconstruction and in different graph metric values describing the brain networks. Our results highlight the importance of taking into account the geometric aspects of acquisitions, especially when comparing diffusion data acquired using different geometries.

  4. 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.

  5. Recognising and combating compassion fatigue in nursing.

    PubMed

    Mendes, Aysha

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

  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. 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

  8. 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.

  9. 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.

  10. 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.

  11. Moderate and strong static magnetic fields directly affect EGFR kinase domain orientation to inhibit cancer cell proliferation

    PubMed Central

    Wang, Wenchao; Li, Zhiyuan; Liu, Juanjuan; Yang, Xingxing; Ji, Xinmiao; Luo, Yan; Hu, Chen; Hou, Yubin; He, Qianqian; Fang, Jun; Wang, Junfeng; Liu, Qingsong; Li, Guohui; Lu, Qingyou; Zhang, Xin

    2016-01-01

    Static magnetic fields (SMFs) can affect cell proliferation in a cell-type and intensity-dependent way but the mechanism remains unclear. At the same time, although the diamagnetic anisotropy of proteins has been proposed decades ago, the behavior of isolated proteins in magnetic fields has not been directly observed. Here we show that SMFs can affect isolated proteins at the single molecular level in an intensity-dependent manner. We found that Epidermal Growth Factor Receptor (EGFR), a protein that is overexpressed and highly activated in multiple cancers, can be directly inhibited by SMFs. Using Liquid-phase Scanning Tunneling Microscopy (STM) to examine pure EGFR kinase domain proteins at the single molecule level in solution, we observed orientation changes of these proteins in response to SMFs. This may interrupt inter-molecular interactions between EGFR monomers, which are critical for their activation. In molecular dynamics (MD) simulations, 1-9T SMFs caused increased probability of EGFR in parallel with the magnetic field direction in an intensity-dependent manner. A superconducting ultrastrong 9T magnet reduced proliferation of CHO-EGFR cells (Chinese Hamster Ovary cells with EGFR overexpression) and EGFR-expressing cancer cell lines by ~35%, but minimally affected CHO cells. We predict that similar effects of magnetic fields can also be applied to some other proteins such as ion channels. Our paper will help clarify some dilemmas in this field and encourage further investigations in order to achieve a better understanding of the biological effects of SMFs. PMID:27223425

  12. 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…

  13. 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.

  14. 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

  15. 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.

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

    PubMed Central

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

    2014-01-01

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

  17. Inhomogeneous ensembles of radical pairs in chemical compasses

    NASA Astrophysics Data System (ADS)

    Procopio, Maria; Ritz, Thorsten

    2016-11-01

    The biophysical basis for the ability of animals to detect the geomagnetic field and to use it for finding directions remains a mystery of sensory biology. One much debated hypothesis suggests that an ensemble of specialized light-induced radical pair reactions can provide the primary signal for a magnetic compass sensor. The question arises what features of such a radical pair ensemble could be optimized by evolution so as to improve the detection of the direction of weak magnetic fields. Here, we focus on the overlooked aspect of the noise arising from inhomogeneity of copies of biomolecules in a realistic biological environment. Such inhomogeneity leads to variations of the radical pair parameters, thereby deteriorating the signal arising from an ensemble and providing a source of noise. We investigate the effect of variations in hyperfine interactions between different copies of simple radical pairs on the directional response of a compass system. We find that the choice of radical pair parameters greatly influences how strongly the directional response of an ensemble is affected by inhomogeneity.

  18. Inhomogeneous ensembles of radical pairs in chemical compasses

    PubMed Central

    Procopio, Maria; Ritz, Thorsten

    2016-01-01

    The biophysical basis for the ability of animals to detect the geomagnetic field and to use it for finding directions remains a mystery of sensory biology. One much debated hypothesis suggests that an ensemble of specialized light-induced radical pair reactions can provide the primary signal for a magnetic compass sensor. The question arises what features of such a radical pair ensemble could be optimized by evolution so as to improve the detection of the direction of weak magnetic fields. Here, we focus on the overlooked aspect of the noise arising from inhomogeneity of copies of biomolecules in a realistic biological environment. Such inhomogeneity leads to variations of the radical pair parameters, thereby deteriorating the signal arising from an ensemble and providing a source of noise. We investigate the effect of variations in hyperfine interactions between different copies of simple radical pairs on the directional response of a compass system. We find that the choice of radical pair parameters greatly influences how strongly the directional response of an ensemble is affected by inhomogeneity. PMID:27804956

  19. The effect of stress and magnetic field orientation on surface Barkhausen noise in pipeline steel

    SciTech Connect

    Jagadish, C.; Clapham, L.; Atherton, D.L. . Dept. of Physics)

    1990-01-01

    Surface Barkhausen noise (SBN) measurements were mae on a 2-percent Mn pipeline steel sample subjected to different levels of applied tensile and compressive isostress. The magnetic field direction was varied through a full 360{degrees}. SBN voltage was found to depend on both stress level and magnetic field direction. The results were analyzed in terms of the reorientation of magnetic moments from axial to circumferential directions with increasing tension. Compression was found to re-align the magnetic moments in the axial direction.

  20. 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…

  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. Electrophoretic and electro-optical studies on the conformation and susceptibility to psoralen crosslinking of magnetically oriented DNA

    SciTech Connect

    Roots, R.J.; Kraft, G.H.; Farinato, R.S.; Tenforde, T.S.

    1982-08-01

    Gel electrophoresis and electro-optical birefringence measurements were performed on the replicative form of bacteriophage phi X-174 DNA subjected to orientation in a homogeneous stationary magnetic field. The conformation of this superhelical double-stranded form of DNA, and its sensitivity to intercalation and crosslinking by a psoralen derivative, were found to be unaffected by a 1 h exposure to a 2.15 Tesla field. In addition, no alteration was detected in the infectivity of the exposed phi X-174 DNA in E. coli bacterial hosts.

  3. Magnetic loss and B(H) behaviour of non-oriented electrical sheets under a trapezoidal exciting field

    NASA Astrophysics Data System (ADS)

    Kedous-Lebouc, A.; Errard, S.; Cornut, B.; Brissonneau, P.

    1994-05-01

    The excess loss and hysteresis response of electrical steel are measured and discussed in the case of trapezoidal field excitation similar to the current provided by a current commutation supply of a self-synchronous rotating machine. Three industrial non-oriented SiFe samples of different magnetic grades and thicknesses are tested using an automatic Epstein frame equipment. The losses and the unusual observed B( H) loops are analysed in terms of the rate of change of the field, the diffusion of the induction inside the sheet and by the calculation of the theoretical hysteresis cycles due to the eddy currents.

  4. 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.

  5. 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.

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

    PubMed

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

    1988-01-01

    The purpose of this study was to determine the effect of orientation of pulsed electromagnetic fields (PEMFs) on cellular proliferation and extracellular matrix synthesis. Bovine articular chondrocytes were cultured in PEMFs (repetitive pulse at 72 Hz) generated using Helmholtz coils oriented either parallel (horizontal) or perpendicular (vertical) to the plane of cell adhesion. Dissipation of signal energy in the form of heat increased the temperature of the PEMF coils by 2 degrees C and the tissue culture medium by 1 degree C. Therefore, control coils, which emitted no PEMFs, were heated to the temperature of PEMF coils by circulating water. Chondrocytes were cultured in 16-mm-well culture plates, and the data for individual wells were pooled as triplicates. Although not observed by microscopic examination of individual wells, positionally dependent electric field effects may be minimized by this approach. PEMFs generated by coils oriented vertically significantly decreased chondrocyte proliferation. The effect was dependent on the concentration of serum in the culture media. At 3% serum concentration, the total cell number attained after 10 days of culture was reduced by 50% in stimulated cultures when compared with controls. At 5% serum concentration, there was no effect. PEMFs applied by coils oriented horizontally did not alter proliferation of articular chondrocytes. PEMFs had no effect on synthesis of extracellular matrix by chondrocytes plated at high density, irrespective of orientation.

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

    PubMed

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

    2005-05-05

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

  8. Compass impurity model of Tb substitution in Sr2IrO4

    NASA Astrophysics Data System (ADS)

    Zhang, Long; Wang, Fa; Lee, Dung-Hai

    2016-10-01

    We show that upon Tb substitution the interaction between the magnetic moments on the impurity Tb4 + ion and its surrounding Ir4 + ions is described by a "compass" model, i.e., an Ising-like interaction favoring the magnetic moments across each bond to align along the bond direction. Such an interaction nucleates quenched magnetic vortices near the impurities and drives a reentrant transition out of the antiferromagnetic ordered phase at low temperatures, hence quickly suppressing the Néel temperature, consistent with the experiment [J. C. Wang et al., Phys. Rev. B 92, 214411 (2015), 10.1103/PhysRevB.92.214411]. As a by-product, we propose that the compass model can be realized in ordered double perovskites composed of spin-orbital-coupled d5 ions and half-closed-shell f7 ions.

  9. 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.

  10. Loving-kindness and compassion meditation: potential for psychological interventions.

    PubMed

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

    2011-11-01

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

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

    PubMed Central

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

    2011-01-01

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

  12. 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

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

    PubMed

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

    2010-04-06

    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

  14. 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.

  15. Magnetic maps in animals: nature's GPS.

    PubMed

    Lohmann, Kenneth J; Lohmann, Catherine M F; Putman, Nathan F

    2007-11-01

    Diverse animals detect the Earth's magnetic field and use it as a cue in orientation and navigation. Most research on magnetoreception has focused on the directional or ;compass' information that can be extracted from the Earth's field. Because the field varies predictably across the surface of the globe, however, it also provides a potential source of positional or 'map' information, which some animals use to steer themselves along migratory pathways or to navigate toward specific target areas. The use of magnetic positional information has been demonstrated in several diverse animals including sea turtles, spiny lobsters, newts and birds, suggesting that such systems are phylogenetically widespread and can function over a wide range of spatial scales. These ;magnetic maps' have not yet been fully characterized. They may be organized in several fundamentally different ways, some of which bear little resemblance to human maps, and they may also be used in conjunction with unconventional navigational strategies.

  16. Plasma expansion into a vacuum with an arbitrarily oriented external magnetic field

    SciTech Connect

    García-Rubio, F. Sanz, J.; Ruocco, A.

    2016-01-15

    Plasma expansion into a vacuum with an external magnetic field is studied under the ideal magnetohydrodynamic hypothesis. The inclination of the magnetic field with respect to the expansion direction is arbitrary, and both the perpendicular and the oblique cases are separately analyzed. A self-similar solution satisfying the boundary conditions is obtained. The interface with the vacuum is treated as a fluid surface, and jump conditions concerning the momentum conservation are imposed. The effect of the intensity of the magnetic field and its inclination is thoroughly studied, and the consistency of the solution for small and large inclinations is investigated.

  17. Microstructure, texture and magnetic properties of strip-cast 1.3% Si non-oriented electrical steels

    NASA Astrophysics Data System (ADS)

    Zhang, Yuanxiang; Xu, Yunbo; Liu, Haitao; Li, Chenggang; Cao, Guangming; Liu, Zhenyu; Wang, Guodong

    2012-10-01

    In this work, the evolution of microstructure, texture and magnetic properties of non-oriented 1.3% silicon steel processed using the twin-roll strip casting was investigated, especially under different solidification structures. A number of microstructures about the as-cast strips show that the initial solidification structure of casting a strip can be controlled by the melt superheats. The microstructures with the average grain size of ˜100-400 μm can be obtained in strips when the melt superheats are from 20 to 60 °C. A nearly random, diffuse, homogeneous texture under a low melt superheat, but comparatively developed {100} oriented grains are formed under a high melt superheat through the cast strip thickness. The relatively low core loss and high magnetic induction can be obtained in the cold rolled and annealed sheets when increasing the initial grain size of cast-strip. The textures in annealed sheets with coarse initial grain size are characterized by the relatively strong Goss component and {001} fiber but weak γ-fiber component, which lead to the high permeability.

  18. 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)

  19. 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.

  20. The compassion-hostility paradox: the interplay of vigilant, prevention-focused self-regulation, compassion, and hostility.

    PubMed

    Keller, Johannes; Pfattheicher, Stefan

    2013-11-01

    The present research examined the notion that the prosocial attitude of compassion is positively related to the antisocial attitude of hostility given that compassion and hostility entail elements reflecting vigilant, prevention-focused self-regulation. In fact, it was found in four samples (N = 4,903) that individuals with a strong vigilant prevention focus reported higher levels on measures of hostility as well as higher levels on compassion than individuals characterized by a weak prevention focus. In addition, compassion and hostility are indeed positively correlated reflecting the Compassion-Hostility Paradox. The positive association between compassion and hostility is substantially reduced when the chronic level of prevention-focused self-regulation is controlled for. A complementary experimental study in which compassion was manipulated revealed an effect of compassion on hostility in chronically prevention-focused individuals.

  1. 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,…

  2. 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)

  3. Nurturing Compassion Development among College Students: A Longitudinal Study

    ERIC Educational Resources Information Center

    Plante, Thomas; Halman, Katherine

    2016-01-01

    Little research exists on the development of compassion among college undergraduates. This study tracks changes in compassion and identifies factors associated with these changes over the course of undergraduate students' college careers, from the time of admittance to the time of graduation. Compassion levels assessed at the point of college…

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

    PubMed

    Harris, Chelsia; Griffin, Mary T Quinn

    2015-01-01

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

  5. 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…

  6. 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…

  7. Compassion satisfaction, compassion fatigue, and burnout in a national sample of trauma treatment therapists.

    PubMed

    Craig, C D; Sprang, G

    2010-05-01

    For behavioral health professionals working with traumatized clients, continuous and prolonged exposure to the stress of working with the myriad of trauma-related stressors experienced by their clients can lead to various responses including burnout, compassion fatigue, and compassion satisfaction. The present study investigates the impact of using evidence-based practices on compassion fatigue, burnout, and compassion satisfaction in a random, national sample of self-identified trauma specialists (N=532). The 30-item Professional Quality of Life Scale (Stamm, 2005) and the 19-item Trauma Practices Questionnaire (Craig & Sprang, 2009) were included in a survey to licensed social workers and psychologists from professional membership rosters. Age and years of experience proved to be powerful predictors of only two of the three criterion variables, with younger professionals reporting higher levels of burnout and more experienced providers endorsing higher levels of compassion satisfaction. The utilization of evidence-based practices predicted statistically significant decreases in compassion fatigue and burnout, and increases in compassion satisfaction. The utility of these findings in understanding the process of trauma transmission between therapist and client as well as directions for future research are discussed.

  8. 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)

  9. Is it possible to receive information about the historical geomagnetic declination from church orientations?

    NASA Astrophysics Data System (ADS)

    Draxler, Andrea; Rauch, Roman; Gruber, Karin; Leohardt, Roman

    2013-04-01

    It is widely known that the main structure of many churches was planned and built in an east-ward direction. This procedure, called "easting", was used for centuries especially in catholic structures. "Easting" usually refers to the direction of sunrise at the church patron's day. Assuming however that this direction is estimated by compasses there could be a significant correlation between the geographic orientation of the churches and the value of magnetic declination at the date of building. In Europe compasses are known since the 11th century. For this study altogether 124 churches located in lower Austria and built between 1100 to 1900 were analysed. Of primary interest is the geographic orientation of the churches, which was extracted out of georeferenced satellite images in Google Earth and the NO Atlas. The measured orientation of the church's nave is then compared to the geographic east direction as well as to the magnetic east direction, according to the magnetic field in the church's construction year which is determined by published geomagnetic field models. The resulting deviations for the geographic east direction split our data into two groups: churches that were built before 1500 and churches that were constructed after 1500. The boundary between these two data sets is marked by the Ottoman wars in the 16th century, where a lot of churches were destroyed. After 1500 the differences between the church's orientation and the geographic east direction are significantly bigger than before the Ottoman wars, so we shifted our focus for the following calculations on the time span from 1100 to 1500, where we found quite small deviations for both the geographic and the magnetic east direction. The principle idea of church orientation, usually referred to as "Easting" is to direct the church to the point of sunrise on the patron saint's day. Therefore we also calculated the solar azimuth on the patron saint's day and compared it to the orientation of the

  10. Preferential orientation of magnetization and interfacial disorder in Co/Au multilayers

    NASA Astrophysics Data System (ADS)

    Quispe-Marcatoma, J.; Pandey, B.; Alayo, W.; de Sousa, M. A.; Pelegrini, F.; Saitovitch, E. Baggio

    2013-10-01

    Two families of Co/Au multilayer films with different interlayer magnetostatic coupling were grown by the DC magnetron sputtering technique. The structure of these films was analyzed by X-ray diffraction (XRD), and the magnetic properties by vibrating sample magnetometer (VSM) and ferromagnetic resonance (FMR) spectroscopy. All these techniques give complementary information about the structure of the multilayers and the magnetization direction as a function of thickness of the Co layers. The structural analysis shows a decrease of the interfacial disorder for increasing Co layer thickness in both groups of samples. This behavior has been correlated with a transition of the magnetization direction from perpendicular to parallel to the films plane. Thin Co layer samples gave high remnant magnetization with very low saturation field while thick Co layer samples showed low remnant magnetization with high value of saturation field. In the FMR study, the spectra showed two resonance modes, which were associated to the internal and interfacial Co atoms. Volume (Kv) and surface (Ks) anisotropy constants were deduced from the FMR experiments and are in good agreement with the reported values for Co/Au multilayers.

  11. Inference of the chromospheric magnetic field orientation in the Ca ii 8542 Å line fibrils

    NASA Astrophysics Data System (ADS)

    Asensio Ramos, A.; de la Cruz Rodríguez, J.; Martínez González, M. J.; Socas-Navarro, H.

    2017-03-01

    Context. Solar chromospheric fibrils, as observed in the core of strong chromospheric spectral lines, extend from photospheric field concentrations suggesting that they trace magnetic field lines. These images have been historically used as proxies of magnetic fields for many purposes. Aims: Use statistical analysis to test whether the association between fibrils and magnetic field lines is justified. Methods: We use a Bayesian hierarchical model to analyze several tens of thousands of pixels in spectro-polarimetric chromospheric images of penumbrae and chromospheric fibrils. We compare the alignment between the field azimuth inferred from the linear polarization signals through the transverse Zeeman effect and the direction of the fibrils in the image. Results: We conclude that, in the analyzed fields of view, fibrils are often well aligned with the magnetic field azimuth. Despite this alignment, the analysis also shows that there is a non-negligible dispersion. In penumbral filaments, we find a dispersion with a standard deviation of 16°, while this dispersion goes up to 34° in less magnetized regions.

  12. 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.

  13. Solution Structure Calculations through Self-Orientation in a Magnetic Field of a Cerium(III) Substituted Calcium-Binding Protein

    NASA Astrophysics Data System (ADS)

    Bertini, Ivano; Janik, Matthias B. L.; Liu, Gaohua; Luchinat, Claudio; Rosato, Antonio

    2001-01-01

    Within the frame of a research aimed at characterizing paramagnetic metal ions capable of inducing self-orientation of metalloproteins in solution, we have studied the complex of the 75-amino-acid calcium-binding protein calbindin D9k with one Ce(III) ion (CaCeCb). Backbone 15N-1H 1J values have been determined for CaCeCb at two different magnetic fields. The above values showed a distinct dependence on the magnetic field, which is caused by the partial orientation of the molecule in solution. The difference in the values at the two magnetic fields provides structural constraints, which have been used to refine the structure of CaCeCb. The refined structure showed an improvement in terms of the number of residues falling in favored regions of the Ramachandran plot. The comparison of the molecular magnetic susceptibility tensor, obtained from the 15N-1H 1J values, with the magnetic susceptibility tensor of the metal, obtained from pseudocontact shifts, showed that the orientation of the molecule in solution is mainly determined by the Ce(III) ion. This paper shows that Ce(III), like low-spin Fe(III) in hemoproteins, is sufficiently magnetically anisotropic to induce self-orientation to an extent which can be exploited for solution structure determination.

  14. 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.

  15. Magnetic properties of Mn{sub 3}O{sub 4} film with a coexistence of two preferential orientations

    SciTech Connect

    Ren, Lizhu; Zhou, Wenqi; Wang, Yunjia; Meng, Meng; Wu, Shuxiang; Li, Shuwei

    2014-07-14

    A Mn{sub 3}O{sub 4} film with a coexistence of two preferential orientations has been grown on a Pt(111)//Si(100) substrate by plasma-assisted molecular beam epitaxy. The structural characteristics and chemical compositions of the film are investigated by using X-ray diffraction, Raman, and X-ray photoelectron spectra in detail. Together with the magnetic tests, the film is demonstrated to be a polycrystalline hausmannite Mn{sub 3}O{sub 4} with no other impurities. Moreover, the hysteresis loops of the film are found to display a step or a characteristic shrinking at low fields. On the other hand, similar magnetic characteristics have also been discovered on the film with two phases grown on a MgAl{sub 2}O{sub 4}(001) substrate. In our opinion, considering the large magnetocrystalline anisotropy and shape anisotropy of the single crystal Mn{sub 3}O{sub 4} film reported in previous works, the special structures and phases of the two films result in both of them as soft+hard magnetic composites, in agreement with some other reports.

  16. The 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

  17. 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

  18. 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.

  19. Peptide backbone orientation and dynamics in spider dragline silk and two-photon excitation in nuclear magnetic and quadrupole resonance

    NASA Astrophysics Data System (ADS)

    Eles, Philip Thomas

    2005-07-01

    In the first part of the dissertation, spider dragline silk is studied by solid state NMR techniques. The dependence of NMR frequency on molecular orientation is exploited using the DECODER experiment to determine the orientation of the protein backbone within the silk fibre. Practical experimental considerations require that the silk fibres be wound about a cylindrical axis perpendicular to the external magnetic field, complicating the reconstruction of the underlying orientation distribution and necess-itating the development of numerical techniques for this purpose. A two-component model of silk incorporating static b-sheets and polyglycine II helices adequately fits the NMR data and suggests that the b-sheets are well aligned along the silk axis (20 FWHM) while the helices are poorly aligned (68 FWHM). The effects of fibre strain, draw rate and hydration on orientation are measured. Measurements of the time-scale for peptide backbone motion indicate that when wet, a strain-dependent frac-tion of the poorly aligned component becomes mobile. This suggests a mechanism for the supercontraction of silk involving latent entropic springs that undergo a local strain-dependent phase transition, driving supercontraction. In the second part of this dissertation a novel method is developed for exciting NMR and nuclear quadrupole resonance (NQR) by rf irradiation at multiple frequencies that sum to (or differ by) the resonance frequency. This is fundamentally different than traditional NMR experiments where irradiation is applied on-resonance. With excitation outside the detection bandwidth, two-photon excitation allows for detection of free induction signals during excitation, completely eliminating receiver dead-time. A theoretical approach to describing two-photon excitation is developed based on average Hamiltonian theory. An intuition for two-photon excitation is gained by analogy to the coherent absorption of multiple photons requiring conservation of total energy and

  20. 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.

  1. An emancipatory theory of compassion for nursing.

    PubMed

    Georges, Jane M

    2013-01-01

    The purpose of this article was to critique and synthesize the trajectory of the work of Dr Jane Georges in Advances in Nursing Science over the past decade in the development of an emancipatory theory of compassion, with implications for contemporary nursing. Specifically, this article (1) summarizes and critiques the work in each stage of its development, describing missing elements at each stage and subsequent development of ideas built upon previous work, and (2) proposes future directions for the work, including the proposal of a theory of compassion within the emancipatory paradigm to guide further scholarly inquiry in nursing.

  2. 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.

  3. 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…

  4. Multiscale description of avian migration: from chemical compass to behaviour modeling

    PubMed Central

    Pedersen, J. Boiden; Nielsen, Claus; Solov’yov, Ilia A.

    2016-01-01

    Despite decades of research the puzzle of the magnetic sense of migratory songbirds has still not been unveiled. Although the problem really needs a multiscale description, most of the individual research efforts were focused on single scale investigations. Here we seek to establish a multiscale link between some of the scales involved, and in particular construct a bridge between electron spin dynamics and migratory bird behaviour. In order to do that, we first consider a model cyclic reaction scheme that could form the basis of the avian magnetic compass. This reaction features a fast spin-dependent process which leads to an unusually precise compass. We then propose how the reaction could be realized in a realistic molecular environment, and argue that it is consistent with the known facts about avian magnetoreception. Finally we show how the microscopic dynamics of spins could possibly be interpreted by a migrating bird and used for the navigational purpose. PMID:27830725

  5. Multiscale description of avian migration: from chemical compass to behaviour modeling

    NASA Astrophysics Data System (ADS)

    Pedersen, J. Boiden; Nielsen, Claus; Solov’Yov, Ilia A.

    2016-11-01

    Despite decades of research the puzzle of the magnetic sense of migratory songbirds has still not been unveiled. Although the problem really needs a multiscale description, most of the individual research efforts were focused on single scale investigations. Here we seek to establish a multiscale link between some of the scales involved, and in particular construct a bridge between electron spin dynamics and migratory bird behaviour. In order to do that, we first consider a model cyclic reaction scheme that could form the basis of the avian magnetic compass. This reaction features a fast spin-dependent process which leads to an unusually precise compass. We then propose how the reaction could be realized in a realistic molecular environment, and argue that it is consistent with the known facts about avian magnetoreception. Finally we show how the microscopic dynamics of spins could possibly be interpreted by a migrating bird and used for the navigational purpose.

  6. Effect of asymmetric hot rolling on texture, microstructure and magnetic properties in a non-grain oriented electrical steel

    NASA Astrophysics Data System (ADS)

    Chen, S.; Butler, J.; Melzer, S.

    2014-11-01

    In this study, both asymmetric hot rolling (AHR) and conventional hot rolling (CHR) were carried out to study the effect of the hot rolling conditions on the evolution of the texture and microstructure in a non-grain oriented (NGO) steel. The microstructure and texture in the subsequent processing stages were characterised and related to the final magnetic properties. The results show that AHR, compared with CHR, tends to homogenise texture through thickness of the hot band strips. AHR results in a higher fraction of the θ-fibre ({0 0 1}) and a lower fraction of the γ-fibre ({1 1 1}) in the hot band strips, which are favourable features in relation to the magnetic properties of the strip. However, the favourable features observed in hot rolled AHR strips are eliminated after cold rolling and annealing. Contrarily, the required θ-fibre is decreased and the unwanted γ-fibre is intensified in the AHR sheet after cold rolling and their strength is maintained in the subsequent process steps. On the other hand, AHR does not produce a discernible change in the grain size in the hot band annealed strip and in the final annealed sheet, except that the magnetic anisotropy in the AHR is improved after skin pass and extra annealing as the result of the redistribution of the texture components within the θ-fibre, no significant improvement of the magnetic properties as a direct consequence of the application of asymmetric hot rolling has been observed under the current AHR experimental conditions.

  7. 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

  8. 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

  9. Smoothed orientational order profile of lipid bilayers by 2H-nuclear magnetic resonance.

    PubMed Central

    Lafleur, M; Fine, B; Sternin, E; Cullis, P R; Bloom, M

    1989-01-01

    A new method has been developed to determine the complete orientational order profile of lipid bilayers using 2H-NMR. The profile is obtained from a single powder spectrum of a lipid which has a saturated chain fully deuteriated. The smoothed order profile is determined directly from the normalized dePaked spectrum assuming a monotonic decrease of the order along the acyl chain. The oscillatory variations of the order at the beginning of the chain are not described by this method. However the smoothed order profile reveals in a straightforward way the crucial features of the anisotropic order of the bilayer. PMID:2605294

  10. 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).

  11. Compassion training alters altruism and neural responses to suffering.

    PubMed

    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

    2013-07-01

    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 (a) short-term compassion training increases altruistic behavior and (b) individual differences in altruism are associated with training-induced changes in neural responses to suffering. In healthy adults, we found that compassion training increased altruistic redistribution of funds to a victim encountered outside of the training context. Furthermore, increased altruistic behavior after compassion training was associated with altered activation in brain regions implicated in social cognition and emotion regulation, including the inferior parietal cortex and dorsolateral prefrontal cortex (DLPFC), and in DLPFC connectivity with the nucleus accumbens. These results suggest that compassion can be cultivated with training and that greater altruistic behavior may emerge from increased engagement of neural systems implicated in understanding the suffering of other people, executive and emotional control, and reward processing.

  12. Highly-oriented molecular arrangements and enhanced magnetic interactions in thin films of CoTTDPz using PTCDA templates.

    PubMed

    Eguchi, Keitaro; Nanjo, Chihiro; Awaga, Kunio; Tseng, Hsiang-Han; Robaschik, Peter; Heutz, Sandrine

    2016-07-14

    In the present work, the templating effect of thin layers of perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) on the growth of cobalt tetrakis(thiadiazole)porphyrazine (CoTTDPz) thin films was examined. X-ray diffraction and optical absorption spectra indicate that while CoTTDPz forms amorphous thin films on the bare substrates, it forms crystalline thin films on the PTCDA templates, in which the molecular planes of CoTTDPz are considered to be parallel to the substrates. Magnetic measurements reveal a significantly enhanced antiferromagnetic interaction of CoTTDPz in the templated thin films, with values reaching over 13 K. The ability to generate crystalline films and to control their orientation using molecular templates is an important strategy in the fields of organic electronics and spintronics in order to tailor the physical properties of organic thin films to suit their intended application.

  13. Chemical shift tensor determination using magnetically oriented microcrystal array (MOMA): 13C solid-state CP NMR without MAS

    NASA Astrophysics Data System (ADS)

    Kusumi, R.; Kimura, F.; Song, G.; Kimura, T.

    2012-10-01

    Chemical shift tensors for the carboxyl and methyl carbons of L-alanine crystals were determined using a magnetically oriented microcrystal array (MOMA) prepared from a microcrystalline powder sample of L-alanine. A MOMA is a single-crystal-like composite in which microcrystals are aligned three-dimensionally in a matrix resin. The single-crystal rotation method was applied to the MOMA to determine the principal values and axes of the chemical shift tensors. The result showed good agreement with the literature data for the single crystal of L-alanine. This demonstrates that the present technique is a powerful tool for determining the chemical shift tensor of a crystal from a microcrystal powder sample.

  14. Charge transfer-induced magnetic exchange bias and electron localization in (111)- and (001)-oriented LaNiO3/LaMnO3 superlattices

    NASA Astrophysics Data System (ADS)

    Wei, Haoming; Barzola-Quiquia, Jose Luis; Yang, Chang; Patzig, Christian; Höche, Thomas; Esquinazi, Pablo; Grundmann, Marius; Lorenz, Michael

    2017-03-01

    High-quality lattice-matched LaNiO3/LaMnO3 superlattices with monolayer terrace structure have been grown on both (111)- and (001)-oriented SrTiO3 substrates by pulsed laser deposition. In contrast to the previously reported experiments, a magnetic exchange bias is observed that reproducibly occurs in both (111)- and (001)-oriented superlattices with the thin single layers of 5 and 7 unit cells, respectively. The exchange bias is theoretically explained by charge transfer-induced magnetic moments at Ni atoms. Furthermore, magnetization data at low temperature suggest two magnetic phases in the superlattices, with Néel temperature around 10 K. Electrical transport measurements reveal a metal-insulator transition with strong localization of electrons in the superlattices with the thin LaNiO3 layers of 4 unit cells, in which the electrical transport is dominated by two-dimensional variable range hopping.

  15. Oriented Attachment of Recombinant Proteins to Agarose-Coated Magnetic Nanoparticles by Means of a β-Trefoil Lectin Domain.

    PubMed

    Acebrón, Iván; Ruiz-Estrada, Amalia G; Luengo, Yurena; Morales, María Del Puerto; Guisán, José Manuel; Mancheño, José Miguel

    2016-11-16

    Design of generic methods aimed at the oriented attachment of proteins at the interfacial environment of magnetic nanoparticles currently represents an active field of research. With this in mind, we have prepared and characterized agarose-coated maghemite nanoparticles to set up a platform for the attachment of recombinant proteins fused to the β-trefoil lectin domain LSL150, a small protein that combines fusion tag properties with agarose-binding capacity. Analysis of the agarose-coated nanoparticles by dynamic light scattering, Fourier transform infrared spectroscopy, and thermogravimetric studies shows that decoupling particle formation from agarose coating provides better results in terms of coating efficiency and particle size distribution. LSL150 interacts with these agarose-coated nanoparticles exclusively through the recognition of the sugars of the polymer, forming highly stable complexes, which in turn can be dissociated ad hoc with the competing sugar lactose. Characterization of the complexes formed with the fusion proteins LSL-EGFP (LSL-tagged enhanced green fluorescent protein from Aquorea victoria) and LSL-BTL2 (LSL-tagged lipase from Geobacillus thermocatenolatus) provided evidence supporting a topologically oriented binding of these molecules to the interface of the agarose-coated nanoparticles. This is consistent with the marked polarity of the β-trefoil structure where the sugar-binding sites and the N- and C-terminus ends are at opposed sides. In summary, LSL150 displays topological and functional features expected from a generic molecular adaptor for the oriented attachment of proteins at the interface of agarose-coated nanoparticles.

  16. The influence of trait-negative affect and compassion satisfaction on compassion fatigue in Australian nurses.

    PubMed

    Craigie, Mark; Osseiran-Moisson, Rebecca; Hemsworth, David; Aoun, Samar; Francis, Karen; Brown, Janie; Hegney, Desley; Rees, Clare

    2016-01-01

    For this study, we examined the nature of the unique relationships trait-negative affect and compassion satisfaction had with compassion fatigue and its components of secondary traumatic stress and burnout in 273 nurses from 1 metropolitan tertiary acute hospital in Western Australia. Participants completed the Professional Quality of Life Scale (Stamm, 2010), Depression Anxiety Stress Scale (Lovibond & Lovibond, 2004), and the State-Trait Anxiety Inventory (Spielberger, Gorsuch, Lushene, Vagg, & Jacobs, 1983). Bivariate correlation and hierarchical regression analyses were performed to examine and investigate 4 hypotheses. The results demonstrate a clear differential pattern of relationships with secondary traumatic stress and burnout for both trait-negative affect and compassion satisfaction. Trait-negative affect was clearly the more important factor in terms of its contribution to overall compassion fatigue and secondary traumatic stress. In contrast, compassion satisfaction's unique protective relationship only related to burnout, and not secondary traumatic stress. The results are therefore consistent with the view that compassion satisfaction may be an important internal resource that protects against burnout, but is not directly influential in protecting against secondary traumatic stress for nurses working in an acute-care hospital environment. With the projected nursing workforce shortages in Australia, it is apparent that a further understanding is warranted of how such personal variables may work as protective and risk factors.

  17. 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.

  18. Transfer of directional information between the polarization compass and the sun compass in desert ants.

    PubMed

    Lebhardt, Fleur; Ronacher, Bernhard

    2015-06-01

    Desert ants, Cataglyphis fortis, perform large foraging excursions during which they continuously compute a home vector that allows them to return to the nest on the shortest way. This type of navigation, termed path integration, needs a compass system and an odometer. Ants use several cues to determine their walking direction, two of the most important ones being the sun position and the polarization pattern of the sky. We tested whether an information transfer is possible from one compass system to the other, which depend on different anatomical substrates. Since the sky's polarization pattern is detected by UV-photoreceptors located in the dorsal rim area (DRA), we used an orange Perspex filter that eliminated the UV part of the spectrum to prevent the use of the polarization compass. The use of the sun compass could be excluded by appropriate screens. In the critical tests the ants had learned a nest-feeder direction with e.g. the sun compass only, and were later tested with the polarization compass, or vice versa. The results show that a transfer is possible in both directions.

  19. Polarized skylight does not calibrate the compass system of a migratory bat.

    PubMed

    Lindecke, Oliver; Voigt, Christian C; Pētersons, Gunārs; Holland, Richard A

    2015-09-01

    In a recent study, Greif et al. (Greif et al. Nat Commun 5, 4488. (doi:10.1038/ncomms5488)) demonstrated a functional role of polarized light for a bat species confronted with a homing task. These non-migratory bats appeared to calibrate their magnetic compass by using polarized skylight at dusk, yet it is unknown if migratory bats also use these cues for calibration. During autumn migration, we equipped Nathusius' bats, Pipistrellus nathusii, with radio transmitters and tested if experimental animals exposed during dusk to a 90° rotated band of polarized light would head in a different direction compared with control animals. After release, bats of both groups continued their journey in the same direction. This observation argues against the use of a polarization-calibrated magnetic compass by this migratory bat and questions that the ability of using polarized light for navigation is a consistent feature in bats. This finding matches with observations in some passerine birds that used polarized light for calibration of their magnetic compass before but not during migration.

  20. Polarized skylight does not calibrate the compass system of a migratory bat

    PubMed Central

    Lindecke, Oliver; Voigt, Christian C.; Pētersons, Gunārs; Holland, Richard A.

    2015-01-01

    In a recent study, Greif et al. (Greif et al. Nat Commun 5, 4488. (doi:10.1038/ncomms5488)) demonstrated a functional role of polarized light for a bat species confronted with a homing task. These non-migratory bats appeared to calibrate their magnetic compass by using polarized skylight at dusk, yet it is unknown if migratory bats also use these cues for calibration. During autumn migration, we equipped Nathusius' bats, Pipistrellus nathusii, with radio transmitters and tested if experimental animals exposed during dusk to a 90° rotated band of polarized light would head in a different direction compared with control animals. After release, bats of both groups continued their journey in the same direction. This observation argues against the use of a polarization-calibrated magnetic compass by this migratory bat and questions that the ability of using polarized light for navigation is a consistent feature in bats. This finding matches with observations in some passerine birds that used polarized light for calibration of their magnetic compass before but not during migration. PMID:26382077

  1. Compassion and Mindfulness in Research among Colleagues

    ERIC Educational Resources Information Center

    Conklin, Hilary

    2009-01-01

    In this article, I offer a case of the predicaments I encountered in conducting teacher education research at my own institution and re-examine these predicaments using an ethic of mindfulness and compassion. I explore how this Buddhist perspective might help researchers navigate what can be a lonely, ethically complicated research journey among…

  2. Topographic Map and Compass Use. Student Manual.

    ERIC Educational Resources Information Center

    Taylor, Michael

    This student manual is designed to introduce students to topographic maps and compass use. The first of five units included in the manual is an introduction to topographic maps. Among the topics discussed in this unit are uses, sources, and care and maintenance of topographic maps. Unit 2 discusses topographic map symbols and colors and provides a…

  3. Service Learning and the Compass Trail

    ERIC Educational Resources Information Center

    Morris, Ronald V.

    2016-01-01

    Students used a compass trail to show how they could perform service to their school. When students performed service learning, they completed a real task that was needed for a grateful audience conjoined with academic content in the lesson. Students worked on the school grounds and used content from their regular curriculum while looking for…

  4. Suffering, compassion and 'doing good medical ethics'.

    PubMed

    de Zulueta, Paquita C

    2015-01-01

    'Doing good medical ethics' involves attending to both the biomedical and existential aspects of illness. For this, we need to bring in a phenomenological perspective to the clinical encounter, adopt a virtue-based ethic and resolve to re-evaluate the goals of medicine, in particular the alleviation of suffering and the role of compassion in everyday ethics.

  5. Compassion: How Do You Teach It?

    ERIC Educational Resources Information Center

    Kohler-Evans, Patty; Barnes, Candice Dowd

    2015-01-01

    Evidence suggests that there is a correlation between the violent images and stories we view through media and the effects those stories have on children and young adults, namely the suppression of compassion. With so much emphasis on academic standards, sometimes social emotional skills are grossly neglected. Students are being taught how to…

  6. A Moral Compass. For Parents Particularly.

    ERIC Educational Resources Information Center

    Klein, Helen Altman

    2002-01-01

    Discusses parents' responsibility to provide their children with a moral compass that comprises respect for others, kindness and caring, honesty and honor, and reverence for life. Recognizes that children experience difficulty in achieving goodness and that good behavior sometimes encounters painful consequences. Suggests that parents model…

  7. Walking alongside Children as They Form Compassion

    ERIC Educational Resources Information Center

    Sanders, Wendy Hinrichs

    2010-01-01

    The affluence in the United States in the recent past has made it tempting to indulge children in individual achievement within a culture of abundance. Parents and teachers worry over how to teach compassion in a culture of abundance and competition for personal success, where children's time is over-scheduled and they are geographically dispersed…

  8. Flight results of the COMPASS-1 picosatellite mission

    NASA Astrophysics Data System (ADS)

    Scholz, A.; Ley, W.; Dachwald, B.; Miau, J. J.; Juang, J. C.

    2010-11-01

    The mission of the COMPASS-1 picosatellite is to take pictures of the earth, to validate a space-borne GPS receiver developed by the German Aerospace Center, and to verify the proper operation of the magnetic attitude control system in orbit. The spacecraft was launched on April 28, 2008 from the Indian space port Sriharikota, as part of the PSLV-C9 world record launch that simultaneously brought ten satellites into orbit. The mission operations were carried out from the ground stations in Aachen and Tainan. Arising difficulties in the communication link were overcome with the support of individuals from the amateur radio community. After several months of mission operation, abundant housekeeping and mission data has been commanded, received and analyzed and is presented in this paper.

  9. Long slide-away discharges in the COMPASS tokamak

    NASA Astrophysics Data System (ADS)

    Ficker, Ondrej; Mlynar, Jan; Vlainic, Milos; Weinzettl, Vladimir; Urban, Jakub; Cavalier, Jordan; Havlicek, Jaroslav; Panek, Radomir; Hron, Martin; Cerovsky, Jaroslav; Vondracek, Petr; Paprok, Richard; Decker, Joan; Peysson, Yves; Bogar, Ondrej; Stahl, Adam; Compass Team

    2016-10-01

    In this contribution, long runaway electron (RE) dominated discharges achieved in the COMPASS tokamak are presented. The extensive length is possible due to a low consumption of available volt-seconds of the tokamak transformer in this type of discharge. Energetic electron losses in this regime seems to be modulated mainly by small oscillations of a radial position (controller setting) unlike in the RE discharges at higher electron density, where various MHD phenomena affect the evolution of the losses. The behaviour of the slide-away plasma is studied using magnetic coils, HXR detectors, ECE system and a pair of 3He proportional counters of neutrons. The plasma scenario is also modelled using Fokker-Planck codes. EUROfusion WP MST1, MST2.

  10. Improving magnetic properties by optimization of textures in non-oriented electrical steel with initial columnar grains

    NASA Astrophysics Data System (ADS)

    Zhang, N.; Yang, P.; Mao, W. M.

    2015-04-01

    This study investigates the processing route to optimize magnetic properties along both rolling and transverse directions, and the evolution of texture during the process is revealed by EBSD technique. The results show that, thinner hot-rolled bands accompanied with coarser structures after normalization are beneficial for promoting the magnetic properties of final sheets. Compared with the 35W300 high-grade NGO steel with a similar composition exhibiting B50 = 1.71T (along RD)/1.67 T (along TD), the B50 values of samples obtained by hot rolling to 1.5mm and subsequent processes are equal to or higher than 1.75T (along RD)/1.69T (along TD). Moreover, a greater quantity of {hk0}<001> oriented nuclei result in stronger {hk0}<001> recrystallization texture in recrystallized warm rolled samples heated at 300°C in advance, and stronger {100}<0vw> texture is achieved in the samples prepared by two-stage annealing method. In addition, the distinct deformation and recrystallization behaviors of {100}<001> and {100}<110> columnar grains are discussed.

  11. Estimating Orientation Using Magnetic and Inertial Sensors and Different Sensor Fusion Approaches: Accuracy Assessment in Manual and Locomotion Tasks

    PubMed Central

    Bergamini, Elena; Ligorio, Gabriele; Summa, Aurora; Vannozzi, Giuseppe; Cappozzo, Aurelio; Sabatini, Angelo Maria

    2014-01-01

    Magnetic and inertial measurement units are an emerging technology to obtain 3D orientation of body segments in human movement analysis. In this respect, sensor fusion is used to limit the drift errors resulting from the gyroscope data integration by exploiting accelerometer and magnetic aiding sensors. The present study aims at investigating the effectiveness of sensor fusion methods under different experimental conditions. Manual and locomotion tasks, differing in time duration, measurement volume, presence/absence of static phases, and out-of-plane movements, were performed by six subjects, and recorded by one unit located on the forearm or the lower trunk, respectively. Two sensor fusion methods, representative of the stochastic (Extended Kalman Filter) and complementary (Non-linear observer) filtering, were selected, and their accuracy was assessed in terms of attitude (pitch and roll angles) and heading (yaw angle) errors using stereophotogrammetric data as a reference. The sensor fusion approaches provided significantly more accurate results than gyroscope data integration. Accuracy improved mostly for heading and when the movement exhibited stationary phases, evenly distributed 3D rotations, it occurred in a small volume, and its duration was greater than approximately 20 s. These results were independent from the specific sensor fusion method used. Practice guidelines for improving the outcome accuracy are provided. PMID:25302810

  12. How dim is dim? Precision of the celestial compass in moonlight and sunlight.

    PubMed

    Dacke, M; Byrne, M J; Baird, E; Scholtz, C H; Warrant, E J

    2011-03-12

    Prominent in the sky, but not visible to humans, is a pattern of polarized skylight formed around both the Sun and the Moon. Dung beetles are, at present, the only animal group known to use the much dimmer polarization pattern formed around the Moon as a compass cue for maintaining travel direction. However, the Moon is not visible every night and the intensity of the celestial polarization pattern gradually declines as the Moon wanes. Therefore, for nocturnal orientation on all moonlit nights, the absolute sensitivity of the dung beetle's polarization detector may limit the precision of this behaviour. To test this, we studied the straight-line foraging behaviour of the nocturnal ball-rolling dung beetle Scarabaeus satyrus to establish when the Moon is too dim--and the polarization pattern too weak--to provide a reliable cue for orientation. Our results show that celestial orientation is as accurate during crescent Moon as it is during full Moon. Moreover, this orientation accuracy is equal to that measured for diurnal species that orient under the 100 million times brighter polarization pattern formed around the Sun. This indicates that, in nocturnal species, the sensitivity of the optical polarization compass can be greatly increased without any loss of precision.

  13. How dim is dim? Precision of the celestial compass in moonlight and sunlight

    PubMed Central

    Dacke, M.; Byrne, M. J.; Baird, E.; Scholtz, C. H.; Warrant, E. J.

    2011-01-01

    Prominent in the sky, but not visible to humans, is a pattern of polarized skylight formed around both the Sun and the Moon. Dung beetles are, at present, the only animal group known to use the much dimmer polarization pattern formed around the Moon as a compass cue for maintaining travel direction. However, the Moon is not visible every night and the intensity of the celestial polarization pattern gradually declines as the Moon wanes. Therefore, for nocturnal orientation on all moonlit nights, the absolute sensitivity of the dung beetle's polarization detector may limit the precision of this behaviour. To test this, we studied the straight-line foraging behaviour of the nocturnal ball-rolling dung beetle Scarabaeus satyrus to establish when the Moon is too dim—and the polarization pattern too weak—to provide a reliable cue for orientation. Our results show that celestial orientation is as accurate during crescent Moon as it is during full Moon. Moreover, this orientation accuracy is equal to that measured for diurnal species that orient under the 100 million times brighter polarization pattern formed around the Sun. This indicates that, in nocturnal species, the sensitivity of the optical polarization compass can be greatly increased without any loss of precision. PMID:21282173

  14. Anchor Node Localization for Wireless Sensor Networks Using Video and Compass Information Fusion

    PubMed Central

    Pescaru, Dan; Curiac, Daniel-Ioan

    2014-01-01

    Distributed sensing, computing and communication capabilities of wireless sensor networks require, in most situations, an efficient node localization procedure. In the case of random deployments in harsh or hostile environments, a general localization process within global coordinates is based on a set of anchor nodes able to determine their own position using GPS receivers. In this paper we propose another anchor node localization technique that can be used when GPS devices cannot accomplish their mission or are considered to be too expensive. This novel technique is based on the fusion of video and compass data acquired by the anchor nodes and is especially suitable for video- or multimedia-based wireless sensor networks. For these types of wireless networks the presence of video cameras is intrinsic, while the presence of digital compasses is also required for identifying the cameras' orientations. PMID:24594614

  15. Non-epitaxially Grown, Oriented L10 FeNiPt Films and Their Magnetic Properties

    NASA Astrophysics Data System (ADS)

    Yan, M. L.; Xu, Y. F.; Sellmyer, D. J.

    2004-03-01

    We report on Ni doped, nonepitaxial L10 FePt thin films with strong texturing. The Ni is used to control and adjust magnetic properties of the films for use as an extremely high-density perpendicular recording media. The FeNiPt films were deposited directly on Si wafers with a (FeNi/Pt)n multilayer structure and subsequent rapid thermal annealing (RTA). Microstructural evolution of the nonepitaxial growth was investigated by XRD. The data show only (00l) peaks, indicating high (001) texture of the FeNiPt films. In comparison with FePt, the (00l) peak positions shifted to higher angle, meaning that Ni is partially substituted for Fe on the L10 lattice. Magnetic properties of these films were investigated by SQUID. The coercivity, measured at room temperature, was about 5 kOe for the film with 10% Ni substitution. This value is suitable for reading and writing in a practical recording media. The coherence length of interaction and temperature dependence of the coercivity are also discussed.

  16. Influence of randomly oriented columnar defects on the irreversible and reversible magnetization of Tl2Ba2CaCu2Ox superconductor

    NASA Astrophysics Data System (ADS)

    Ossandon, J. G.; Thompson, J. R.; Krusin-Elbaum, L.; Kim, H. J.; Christen, D. K.; Song, K. J.; Ullmann, J. L.

    2001-09-01

    Bulk polycrystalline Tl2Ba2CaCu2Ox materials were irradiated with 0.8 GeV protons to introduce randomly oriented columnar defects. Proton fluences up to 8.7×1020 m-2 were used to create defect arrays corresponding to a `matching field' of 1.5 T. Studies were conducted on the superconductive transition temperature, the Meissner fraction, the intragrain persistent current density against the magnetic field and temperature, and the equilibrium magnetization. The magnetization was modelled using London theory with the addition of vortex-defect interactions, yielding physically reasonable parameters.

  17. Collinear ferromagnetism and spin orientation in the molecule-based magnets M[N(CN){sub 2}]{sub 2} (M=Co,Ni)

    SciTech Connect

    Kmety, C.R.; Manson, J.L.; Huang, Q. |; Lynn, J.W.; Erwin, R.W.; Miller, J.S.; Epstein, A.J. |

    1999-07-01

    Zero-field unpolarized neutron powder diffraction has been used to study the low-T magnetic structure and {ital T}-dependent crystal structure of M[N(CN){sub 2}]{sub 2} (M=Co,Ni). Both compounds show collinear ferromagnetism with spin orientation along the {ital c} axis. The results provide the determination of a complete magnetic structure in the ordered state for a molecule-based magnet. The {ital c} lattice parameter exhibits negative thermal expansion, explained by a wine-rack-like deformation. {copyright} {ital 1999} {ital The American Physical Society}

  18. Compass Cells in the Brain of an Insect Are Sensitive to Novel Events in the Visual World.

    PubMed

    Bockhorst, Tobias; Homberg, Uwe

    2015-01-01

    The central complex of the insect brain comprises a group of neuropils involved in spatial orientation and memory. In fruit flies it mediates place learning based on visual landmarks and houses neurons that encode the orientation for goal-directed locomotion, based on landmarks and self-motion cues for angular path-integration. In desert locusts, the central complex holds a compass-like representation of head directions, based on the polarization pattern of skylight. Through intracellular recordings from immobilized locusts, we investigated whether sky compass neurons of the central complex also represent the position or any salient feature of possible landmarks, in analogy to the observations in flies. Neurons showed strongest responses to the novel appearance of a small moving square, but we found no evidence for a topographic representation of object positions. Responses to an individual square were independent of direction of motion and trajectory, but showed rapid adaptation to successive stimulation, unaffected by changing the direction of motion. Responses reappeared, however, if the moving object changed its trajectory or if it suddenly reversed moving direction against the movement of similar objects that make up a coherent background-flow as induced by ego-motion. Response amplitudes co-varied with the precedent state of dynamic background activity, a phenomenon that has been related to attention-dependent saliency coding in neurons of the mammalian primary visual cortex. The data show that neurons of the central complex of the locust brain are visually bimodal, signaling sky compass direction and the novelty character of moving objects. These response properties might serve to attune compass-aided locomotor control to unexpected events in the environment. The difference to data obtained in fruit flies might relate to differences in the lifestyle of landmark learners (fly) and compass navigators (locust), point to the existence of parallel networks for

  19. Compass Cells in the Brain of an Insect Are Sensitive to Novel Events in the Visual World

    PubMed Central

    Bockhorst, Tobias; Homberg, Uwe

    2015-01-01

    The central complex of the insect brain comprises a group of neuropils involved in spatial orientation and memory. In fruit flies it mediates place learning based on visual landmarks and houses neurons that encode the orientation for goal-directed locomotion, based on landmarks and self-motion cues for angular path-integration. In desert locusts, the central complex holds a compass-like representation of head directions, based on the polarization pattern of skylight. Through intracellular recordings from immobilized locusts, we investigated whether sky compass neurons of the central complex also represent the position or any salient feature of possible landmarks, in analogy to the observations in flies. Neurons showed strongest responses to the novel appearance of a small moving square, but we found no evidence for a topographic representation of object positions. Responses to an individual square were independent of direction of motion and trajectory, but showed rapid adaptation to successive stimulation, unaffected by changing the direction of motion. Responses reappeared, however, if the moving object changed its trajectory or if it suddenly reversed moving direction against the movement of similar objects that make up a coherent background-flow as induced by ego-motion. Response amplitudes co-varied with the precedent state of dynamic background activity, a phenomenon that has been related to attention-dependent saliency coding in neurons of the mammalian primary visual cortex. The data show that neurons of the central complex of the locust brain are visually bimodal, signaling sky compass direction and the novelty character of moving objects. These response properties might serve to attune compass-aided locomotor control to unexpected events in the environment. The difference to data obtained in fruit flies might relate to differences in the lifestyle of landmark learners (fly) and compass navigators (locust), point to the existence of parallel networks for

  20. Switching of magnetic easy-axis using crystal orientation for large perpendicular coercivity in CoFe2O4 thin film.

    PubMed

    Shirsath, Sagar E; Liu, Xiaoxi; Yasukawa, Yukiko; Li, Sean; Morisako, Akimitsu

    2016-07-20

    Perpendicular magnetization and precise control over the magnetic easy axis in magnetic thin film is necessary for a variety of applications, particularly in magnetic recording media. A strong (111) orientation is successfully achieved in the CoFe2O4 (CFO) thin film at relatively low substrate temperature of 100 °C, whereas the (311)-preferred randomly oriented CFO is prepared at room temperature by the DC magnetron sputtering technique. The oxygen-deficient porous CFO film after post-annealing gives rise to compressive strain perpendicular to the film surface, which induces large perpendicular coercivity. We observe the coercivity of 11.3 kOe in the 40-nm CFO thin film, which is the highest perpendicular coercivity ever achieved on an amorphous SiO2/Si substrate. The present approach can guide the systematic tuning of the magnetic easy axis and coercivity in the desired direction with respect to crystal orientation in the nanoscale regime. Importantly, this can be achieved on virtually any type of substrate.

  1. Switching of magnetic easy-axis using crystal orientation for large perpendicular coercivity in CoFe2O4 thin film

    NASA Astrophysics Data System (ADS)

    Shirsath, Sagar E.; Liu, Xiaoxi; Yasukawa, Yukiko; Li, Sean; Morisako, Akimitsu

    2016-07-01

    Perpendicular magnetization and precise control over the magnetic easy axis in magnetic thin film is necessary for a variety of applications, particularly in magnetic recording media. A strong (111) orientation is successfully achieved in the CoFe2O4 (CFO) thin film at relatively low substrate temperature of 100 °C, whereas the (311)-preferred randomly oriented CFO is prepared at room temperature by the DC magnetron sputtering technique. The oxygen-deficient porous CFO film after post-annealing gives rise to compressive strain perpendicular to the film surface, which induces large perpendicular coercivity. We observe the coercivity of 11.3 kOe in the 40-nm CFO thin film, which is the highest perpendicular coercivity ever achieved on an amorphous SiO2/Si substrate. The present approach can guide the systematic tuning of the magnetic easy axis and coercivity in the desired direction with respect to crystal orientation in the nanoscale regime. Importantly, this can be achieved on virtually any type of substrate.

  2. Switching of magnetic easy-axis using crystal orientation for large perpendicular coercivity in CoFe2O4 thin film

    PubMed Central

    Shirsath, Sagar E.; Liu, Xiaoxi; Yasukawa, Yukiko; Li, Sean; Morisako, Akimitsu

    2016-01-01

    Perpendicular magnetization and precise control over the magnetic easy axis in magnetic thin film is necessary for a variety of applications, particularly in magnetic recording media. A strong (111) orientation is successfully achieved in the CoFe2O4 (CFO) thin film at relatively low substrate temperature of 100 °C, whereas the (311)-preferred randomly oriented CFO is prepared at room temperature by the DC magnetron sputtering technique. The oxygen-deficient porous CFO film after post-annealing gives rise to compressive strain perpendicular to the film surface, which induces large perpendicular coercivity. We observe the coercivity of 11.3 kOe in the 40-nm CFO thin film, which is the highest perpendicular coercivity ever achieved on an amorphous SiO2/Si substrate. The present approach can guide the systematic tuning of the magnetic easy axis and coercivity in the desired direction with respect to crystal orientation in the nanoscale regime. Importantly, this can be achieved on virtually any type of substrate. PMID:27435010

  3. Relative effect(s) of texture and grain size on magnetic properties in a low silicon non-grain oriented electrical steel

    NASA Astrophysics Data System (ADS)

    PremKumar, R.; Samajdar, I.; Viswanathan, N. N.; Singal, V.; Seshadri, V.

    2003-08-01

    Hot rolled low Si (silicon) non-grain oriented electrical steel was cold rolled to different reductions. Cold rolled material was subsequently recrystallized, 650°C and 2 h, and then temper rolled (to 7% reduction) for the final grain growth annealing and decarburization treatment at 850°C for 2-24 h. The development of texture, grain size and magnetic properties were characterized at different stages of processing. Effect of texture on magnetic properties (watt loss and permeability) was observed to be best represented by the ratio of volume fractions of (1 1 1)/(0 0 1) fibers, as estimated by convoluting X-ray ODFs (orientation distribution functions) with respective model functions. Such a ratio was termed as generalized texture factor (tf) for the non-grain oriented electrical steel. An effort was made to delink effects of grain size and texture, as represented by respective tf, on watt loss and permeability by careful analysis of experimental data. In general, low tf and/or high grain size were responsible for low watt loss and high permeability. However, individual effect of grain size or tf on magnetic properties was less significant at low tf or large grain size, respectively. An attempt was made to fit regression equations, namely—linear, exponential and power, relating magnetic properties with tf and grain size, limiting the fitting parameters to 3. Least standard deviations, between experimental and predicted values, were obtained by power regression equations for both magnetic properties.

  4. Effects of vortex line shape on critical current density in high Tc superconducting film with nano-rod pinning centers under applied magnetic field of various orientations

    NASA Astrophysics Data System (ADS)

    Kwak, K.; Rhee, J.; Lee, W.; Lee, H.; Youm, D.; Yoo, J.

    2013-03-01

    We measured magneto-optical images (MOIs) on a coated conductor comprised of (Gd,Y)1Ba2Cu3O7-δ-BaZrO3 film under applied magnetic field of various orientations. MOIs showed systematic changes of asymmetric distribution of magnetic flux density and critical current density. TEM measurements showed that nano-rod pinning centers (RPCs) tilt by ∼13° from the c-axis. We were able to explain the results of MOI measurements using a simple model calculation about vortex line shapes, which change according to the magnitude and the orientation of applied magnetic field. In this model the critical current density, which is due to the vortex pinning, is determined by the geometrical relationship of the curved vortex lines and the tilted RPCs.

  5. Tuning magnetic anisotropy in (001) oriented L1{sub 0} (Fe{sub 1-x}Cu{sub x}){sub 55}Pt{sub 45} films

    SciTech Connect

    Gilbert, Dustin A.; Liu, Kai; Wang, Liang-Wei; Lai, Chih-Huang; Klemmer, Timothy J.; Thiele, Jan-Ulrich

    2013-04-01

    We have achieved (001) oriented L1{sub 0} (Fe{sub 1-x}Cu{sub x}){sub 55}Pt{sub 45} thin films, with magnetic anisotropy up to 3.6 Multiplication-Sign 10{sup 7} erg/cm{sup 3}, using atomic-scale multilayer sputtering and post annealing at 400 Degree-Sign C for 10 s. By fixing the Pt concentration, structure and magnetic properties are systematically tuned by the Cu addition. Increasing Cu content results in an increase in the tetragonal distortion of the L1{sub 0} phase, significant changes to the film microstructure, and lowering of the saturation magnetization and anisotropy. The relatively convenient synthesis conditions, along with the tunable magnetic properties, make such materials highly desirable for future magnetic recording technologies.

  6. 77 FR 41804 - Solicitation for a Cooperative Agreement: Development of Materials Specific to Compassion Fatigue...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-16

    ... Specific to Compassion Fatigue and Vicarious Trauma in Corrections AGENCY: National Institute of... to define, identify, and address compassion fatigue and vicarious trauma within the corrections..., acknowledge, and address vicarious trauma and compassion fatigue within the corrections profession....

  7. Conformation of alamethicin in oriented phospholipid bilayers determined by (15)N solid-state nuclear magnetic resonance.

    PubMed Central

    Bak, M; Bywater, R P; Hohwy, M; Thomsen, J K; Adelhorst, K; Jakobsen, H J; Sørensen, O W; Nielsen, N C

    2001-01-01

    The conformation of the 20-residue antibiotic ionophore alamethicin in macroscopically oriented phospholipid bilayers has been studied using (15)N solid-state nuclear magnetic resonance (NMR) spectroscopy in combination with molecular modeling and molecular dynamics simulations. Differently (15)N-labeled variants of alamethicin and an analog with three of the alpha-amino-isobutyric acid residues replaced by alanines have been investigated to establish experimental structural constraints and determine the orientation of alamethicin in hydrated phospholipid (dimyristoylphosphatidylcholine) bilayers and to investigate the potential for a major kink in the region of the central Pro(14) residue. From the anisotropic (15)N chemical shifts and (1)H-(15)N dipolar couplings determined for alamethicin with (15)N-labeling on the Ala(6), Val(9), and Val(15) residues and incorporated into phospholipid bilayer with a peptide:lipid molar ratio of 1:8, we deduce that alamethicin has a largely linear alpha-helical structure spanning the membrane with the molecular axis tilted by 10-20 degrees relative to the bilayer normal. In particular, we find compatibility with a straight alpha-helix tilted by 17 degrees and a slightly kinked molecular dynamics structure tilted by 11 degrees relative to the bilayer normal. In contrast, the structural constraints derived by solid-state NMR appear not to be compatible with any of several model structures crossing the membrane with vanishing tilt angle or the earlier reported x-ray diffraction structure (Fox and Richards, Nature. 300:325-330, 1982). The solid-state NMR-compatible structures may support the formation of a left-handed and parallel multimeric ion channel. PMID:11509381

  8. Nuclear magnetic relaxation induced by exchange-mediated orientational randomization: Longitudinal relaxation dispersion for spin I = 1

    NASA Astrophysics Data System (ADS)

    Nilsson, Tomas; Halle, Bertil

    2012-08-01

    The frequency dependence of the longitudinal relaxation rate, known as the magnetic relaxation dispersion (MRD), can provide a frequency-resolved characterization of molecular motions in complex biological and colloidal systems on time scales ranging from 1 ns to 100 μs. The conformational dynamics of immobilized proteins and other biopolymers can thus be probed in vitro or in vivo by exploiting internal water molecules or labile hydrogens that exchange with a dominant bulk water pool. Numerous water 1H and 2H MRD studies of such systems have been reported, but the widely different theoretical models currently used to analyze the MRD data have resulted in divergent views of the underlying molecular motions. We have argued that the essential mechanism responsible for the main dispersion is the exchange-mediated orientational randomization (EMOR) of anisotropic nuclear (electric quadrupole or magnetic dipole) couplings when internal water molecules or labile hydrogens escape from orientationally confining macromolecular sites. In the EMOR model, the exchange process is thus not just a means of mixing spin populations but it is also the direct cause of spin relaxation. Although the EMOR theory has been used in several studies to analyze water 2H MRD data from immobilized biopolymers, the fully developed theory has not been described. Here, we present a comprehensive account of a generalized version of the EMOR theory for spin I = 1 nuclides like 2H. As compared to a previously described version of the EMOR theory, the present version incorporates three generalizations that are all essential in applications to experimental data: (i) a biaxial (residual) electric field gradient tensor, (ii) direct and indirect effects of internal motions, and (iii) multiple sites with different exchange rates. In addition, we describe and assess different approximations to the exact EMOR theory that are useful in various regimes. In particular, we consider the experimentally important

  9. Fiber orientation measurements by diffusion tensor imaging improve hydrogen-1 magnetic resonance spectroscopy of intramyocellular lipids in human leg muscles

    PubMed Central

    Valaparla, Sunil K.; Gao, Feng; Daniele, Giuseppe; Abdul-Ghani, Muhammad; Clarke, Geoffrey D.

    2015-01-01

    Abstract. Twelve healthy subjects underwent hydrogen-1 magnetic resonance spectroscopy (H1-MRS) acquisition (15×15×15  mm3), diffusion tensor imaging (DTI) with a b-value of 600  s mm−2, and fat-water magnetic resonance imaging (MRI) using the Dixon method. Subject-specific muscle fiber orientation, derived from DTI, was used to estimate the lipid proton spectral chemical shift. Pennation angles were measured as 23.78 deg in vastus lateralis (VL), 17.06 deg in soleus (SO), and 8.49 deg in tibialis anterior (TA) resulting in a chemical shift between extramyocellular lipids (EMCL) and intramyocellular lipids (IMCL) of 0.15, 0.17, and 0.19 ppm, respectively. IMCL concentrations were 8.66±1.24  mmol kg−1, 6.12±0.77  mmol kg−1, and 2.33±0.19  mmol kg−1 in SO, VL, and TA, respectively. Significant differences were observed in IMCL and EMCL pairwise comparisons in SO, VL, and TA (p<0.05). Strong correlations were observed between total fat fractions from H1-MRS and Dixon MRI for VL (r=0.794), SO (r=0.655), and TA (r=0.897). Bland-Altman analysis between fat fractions (FFMRS and FFMRI) showed good agreement with small limits of agreement (LoA): bias=−0.21% (LoA: −1.12% to 0.69%) in VL, bias=0.025% (LoA: −1.28% to 1.33%) in SO, and bias=−0.13% (LoA: −0.74% to 0.47%) in TA. The results of this study demonstrate the variation in muscle fiber orientation and lipid concentrations in these three skeletal muscle types. PMID:26158115

  10. Nuclear magnetic relaxation induced by exchange-mediated orientational randomization: longitudinal relaxation dispersion for spin I = 1.

    PubMed

    Nilsson, Tomas; Halle, Bertil

    2012-08-07

    The frequency dependence of the longitudinal relaxation rate, known as the magnetic relaxation dispersion (MRD), can provide a frequency-resolved characterization of molecular motions in complex biological and colloidal systems on time scales ranging from 1 ns to 100 μs. The conformational dynamics of immobilized proteins and other biopolymers can thus be probed in vitro or in vivo by exploiting internal water molecules or labile hydrogens that exchange with a dominant bulk water pool. Numerous water (1)H and (2)H MRD studies of such systems have been reported, but the widely different theoretical models currently used to analyze the MRD data have resulted in divergent views of the underlying molecular motions. We have argued that the essential mechanism responsible for the main dispersion is the exchange-mediated orientational randomization (EMOR) of anisotropic nuclear (electric quadrupole or magnetic dipole) couplings when internal water molecules or labile hydrogens escape from orientationally confining macromolecular sites. In the EMOR model, the exchange process is thus not just a means of mixing spin populations but it is also the direct cause of spin relaxation. Although the EMOR theory has been used in several studies to analyze water (2)H MRD data from immobilized biopolymers, the fully developed theory has not been described. Here, we present a comprehensive account of a generalized version of the EMOR theory for spin I = 1 nuclides like (2)H. As compared to a previously described version of the EMOR theory, the present version incorporates three generalizations that are all essential in applications to experimental data: (i) a biaxial (residual) electric field gradient tensor, (ii) direct and indirect effects of internal motions, and (iii) multiple sites with different exchange rates. In addition, we describe and assess different approximations to the exact EMOR theory that are useful in various regimes. In particular, we consider the experimentally

  11. On the dependence on the magnetic field orientation of the composite fermion effective mass

    NASA Astrophysics Data System (ADS)

    Gee, P. J.; Singleton, J.; Uji, S.; Aoki, H.; Foxon, C. T. B.; Harris, J. J.

    1996-12-01

    The composite fermion (CF) model has been strikingly successful in describing many aspects of the fractional quantum Hall effect (FQHE) observed in two-dimensional electron systems (2DES). In the CF picture, the FQHE is the integer quantum Hall effect of the CFs. In order to assess the effect of an in-plane magnetic field on the CFs we have examined the temperature dependence 0953-8984/8/49/029/img9 of the oscillations in 0953-8984/8/49/029/img10 in a high-mobility GaAs - (Ga, Al)As heterojunction close to Landau level filling factors 0953-8984/8/49/029/img11 and 0953-8984/8/49/029/img12 for many different values of 0953-8984/8/49/029/img13, the angle between the normal to the 2DES and the magnetic field. The CF energy gaps were evaluated at each angle using a variant of the Lifshitz - Kosevich approach. Close to 0953-8984/8/49/029/img11, it was found that the CF gaps at each angle could be fitted to within experimental errors using a constant CF effective mass. However, the CF effective mass was found not to follow the 0953-8984/8/49/029/img13-dependence expected for a purely 2D system; i.e. the CF energy gap at fixed 0953-8984/8/49/029/img16 grows markedly with increasing in-plane field. Around 0953-8984/8/49/029/img17 the situation is more complex, and the oscillations of the energy gaps at 0953-8984/8/49/029/img18 and 0953-8984/8/49/029/img19 as 0953-8984/8/49/029/img13 varied were interpreted using a recent model of two independent CF Landau fans separated by the Pauli spin splitting (Du R R, Yeh A S, Stormer H L, Tsui D C, Pfeiffer L N and West K W 1995 Phys. Rev. Lett. 75 3926). However, whilst the model qualitatively predicts some of the behaviour of the 0953-8984/8/49/029/img10-minima, it is unable to account for the absolute sizes of the energy gaps. In order to reproduce the gaps at 0953-8984/8/49/029/img22 and 0953-8984/8/49/029/img19 quantitatively, an angle-dependent CF mass (as observed close to 0953-8984/8/49/029/img11) is required. The data suggest

  12. Monitoring tools of COMPASS experiment at CERN

    NASA Astrophysics Data System (ADS)

    Bodlak, M.; Frolov, V.; Huber, S.; Jary, V.; Konorov, I.; Levit, D.; Novy, J.; Salac, R.; Tomsa, J.; Virius, M.

    2015-12-01

    This paper briefly introduces the data acquisition system of the COMPASS experiment and is mainly focused on the part that is responsible for the monitoring of the nodes in the whole newly developed data acquisition system of this experiment. The COMPASS is a high energy particle experiment with a fixed target located at the SPS of the CERN laboratory in Geneva, Switzerland. The hardware of the data acquisition system has been upgraded to use FPGA cards that are responsible for data multiplexing and event building. The software counterpart of the system includes several processes deployed in heterogenous network environment. There are two processes, namely Message Logger and Message Browser, taking care of monitoring. These tools handle messages generated by nodes in the system. While Message Logger collects and saves messages to the database, the Message Browser serves as a graphical interface over the database containing these messages. For better performance, certain database optimizations have been used. Lastly, results of performance tests are presented.

  13. Polarised Drell-Yan at COMPASS

    NASA Astrophysics Data System (ADS)

    Longo, Riccardo

    2017-03-01

    The COMPASS experiment at CERN took the polarised Drell-Yan data in 2015. The muon pairs originating from 190 GeV/c pion collisions with polarised protons provide a way of accessing the transverse momentum dependent parton distribution functions of the nucleon. The study of the azimuthal spin asymmetries in Drell-Yan complements a wealth of results already obtained from transversely polarised semi-inclusive deep inelastic scattering at COMPASS. The first results from the polarised Drell-Yan measurements will be shown in the context of the previously obtained SIDIS results. The expected impact of these data will be discussed, as well as prospects for future Drell-Yan related studies.

  14. The installation and correction of compasses in airplanes

    NASA Technical Reports Server (NTRS)

    Schoeffel, M F

    1927-01-01

    The saving of time that results from flying across country on compass headings is beginning to be widely recognized. At the same time the general use of steel tube fuselages has made a knowledge of compass correction much more necessary than was the case when wooden fuselages were the rule. This paper has been prepared primarily for the benefit of the pilot who has never studied navigation and who does not desire to go into the subject more deeply than to be able to fly compass courses with confidence. It also contains material for the designer who wishes to install his compasses with the expectation that they may be accurately corrected.

  15. Recent results from COMPASS muon scattering measurements

    NASA Astrophysics Data System (ADS)

    Capozza, Luigi; Compass Collaboration

    2012-10-01

    A sample of recent results in muon scattering measurements from the COMPASS experiment at CERN will be reviewed. These include high energy processes with longitudinally polarised proton and deuteron targets. High energy polarised measurements provide important constraints for studying the nucleon spin structure and thus permit to test the applicability of the theoretical framework of factorisation theorems and perturbative QCD. Specifically, latest results on longitudinal quark polarisation, quark helicity densities and gluon polarisation will be reviewed.

  16. The Lambda Method for the GNSS Compass

    NASA Astrophysics Data System (ADS)

    Teunissen, P. J. G.

    Global Navigation Satellite System carrier phase ambiguity resolution is the key to high precision positioning and attitude determination. In this contribution the author considers the GNSS compass model. The integer least-squares estimators are derived and the various steps involved in the ambiguity resolution process are discussed. This includes the method that has successfully been used by Park & Teunissen, 2003. Emphasized is the unaided, single frequency, single epoch case, since this is considered the most challenging mode of GNSS attitude determination.

  17. Compassion Practices and HCAHPS: Does Rewarding and Supporting Workplace Compassion Influence Patient Perceptions?

    PubMed Central

    McClelland, Laura E; Vogus, Timothy J

    2014-01-01

    Objective To examine the benefits of compassion practices on two indicators of patient perceptions of care quality—the Hospital Consumer Assessment of Healthcare Providers and systems (HCAHPS) overall hospital rating and likelihood of recommending. Study Setting Two hundred sixty-nine nonfederal acute care U.S. hospitals. Study Design Cross-sectional study. Data Collection Surveys collected from top-level hospital executives. Publicly reported HCAHPS data from October 2012 release. Principal Findings Compassion practices, a measure of the extent to which a hospital rewards compassionate acts and compassionately supports its employees (e.g., compassionate employee awards, pastoral care for employees), is significantly and positively associated with hospital ratings and likelihood of recommending. Conclusions Our findings illustrate the benefits for patients of specific and actionable organizational practices that provide and reinforce compassion. PMID:24837713

  18. The invisible cues that guide king penguin chicks home: use of magnetic and acoustic cues during orientation and short-range navigation.

    PubMed

    Nesterova, Anna P; Chiffard, Jules; Couchoux, Charline; Bonadonna, Francesco

    2013-04-15

    King penguins (Aptenodytes patagonicus) live in large and densely populated colonies, where navigation can be challenging because of the presence of many conspecifics that could obstruct locally available cues. Our previous experiments demonstrated that visual cues were important but not essential for king penguin chicks' homing. The main objective of this study was to investigate the importance of non-visual cues, such as magnetic and acoustic cues, for chicks' orientation and short-range navigation. In a series of experiments, the chicks were individually displaced from the colony to an experimental arena where they were released under different conditions. In the magnetic experiments, a strong magnet was attached to the chicks' heads. Trials were conducted in daylight and at night to test the relative importance of visual and magnetic cues. Our results showed that when the geomagnetic field around the chicks was modified, their orientation in the arena and the overall ability to home was not affected. In a low sound experiment we limited the acoustic cues available to the chicks by putting ear pads over their ears, and in a loud sound experiment we provided additional acoustic cues by broadcasting colony sounds on the opposite side of the arena to the real colony. In the low sound experiment, the behavior of the chicks was not affected by the limited sound input. In the loud sound experiment, the chicks reacted strongly to the colony sound. These results suggest that king penguin chicks may use the sound of the colony while orienting towards their home.

  19. Smartstones: a small e-compass, accelerometer and gyroscope embedded in stones

    NASA Astrophysics Data System (ADS)

    Gronz, Oliver; Hiller, Priska H.; Wirtz, Stefan; Becker, Kerstin; Iserloh, Thomas; Aberle, Jochen; Casper, Markus C.

    2015-04-01

    Pebbles or rock fragments influence soil erosion processes in various ways: they can protect the soil but also enhance the erosion as soon as they are moved by water and impact onto soil. So far, stone-embedded devices to measure the movements have been quite big, up to several decimetres, which does not allow for the analysis of pebbles from medium and coarse gravel classes. In this study, we used a novel device called Smartstones, which is significantly smaller. The Smartstone device's dimensions are 55 mm in length, 8 mm in diameter and an approximately 70 mm long flexible antenna (device developer: SMART-RFID solutions Rheinberg, Germany). It is powered by two button cells, contains an own data storage and is able to wait inactive for longer times until it is activated by movement. It communicates via active RFID (radio frequency identification) technology to a Linux gateway, which stores the sensor data in a database after transmission and is able to handle several devices simultaneously. The device contains a Bosch sensor that measures magnetic flux density, acceleration and rotation, in each case for / around three axes. In our study, the device has been used in a laboratory flume (270 cm in length, 5° to 10° slope, approx. 2 cm water level, mean flow velocities between 0.66 and 1 ms-1) in combination with a high speed camera to capture the movement of the pebbles. The simultaneous usage of two capture devices allows for a comparison of the results: movement patterns derived from image analysis and sensor data analysis. In the device's first software version, all three sensors - acceleration, compass, and gyroscope - were active. The acquisition of all values resulted in a sampling rate of 10 Hz. After the experiments using this setup, the data analysis of the high speed images and the device's data showed that the pebble reached rotation velocities beyond 5 rotations per second, even on the relatively short flume and low water levels. Thus, the device

  20. The COMPASS RICH-1 detector upgrade

    NASA Astrophysics Data System (ADS)

    Abbon, P.; Alekseev, M.; Angerer, H.; Apollonio, M.; Birsa, R.; Bordalo, P.; Bradamante, F.; Bressan, A.; Busso, L.; Chiosso, M.; Ciliberti, P.; Colantoni, M. L.; Costa, S.; Dalla Torre, S.; Dafni, T.; Delagnes, E.; Deschamps, H.; Diaz, V.; Dibiase, N.; Duic, V.; Eyrich, W.; Faso, D.; Ferrero, A.; Finger, M.; Finger, M., Jr.; Fischer, H.; Gerassimov, S.; Giorgi, M.; Gobbo, B.; Hagemann, R.; von Harrach, D.; Heinsius, F. H.; Joosten, R.; Ketzer, B.; Königsmann, K.; Kolosov, V. N.; Konorov, I.; Kramer, D.; Kunne, F.; Lehmann, A.; Levorato, S.; Maggiora, A.; Magnon, A.; Mann, A.; Martin, A.; Menon, G.; Mutter, A.; Nähle, O.; Nerling, F.; Neyret, D.; Pagano, P.; Panebianco, S.; Panzieri, D.; Paul, S.; Pesaro, G.; Polak, J.; Rebourgeard, P.; Robinet, F.; Rocco, E.; Schiavon, P.; Schill, C.; Schröder, W.; Silva, L.; Slunecka, M.; Sozzi, F.; Steiger, L.; Sulc, M.; Svec, M.; Tessarotto, F.; Teufel, A.; Wollny, H.

    2008-08-01

    The COMPASS experiment at CERN provides hadron identification in a wide momentum range employing a large size gaseous Ring Imaging CHerenkov detector (RICH). The presence of large uncorrelated background in the COMPASS environment was limiting the efficiency of COMPASS RICH-1 in the very forward regime. A major upgrade of RICH-1 required a new technique for Cherenkov photon detection at count rates of several 106/s per channel in the central detector part, and a read-out system allowing for trigger rates of up to 100 kHz. To cope with these requirements, the photon detectors of the central region have been replaced with a fast photon detection system described here, while, in the peripheral regions, the existing multi-wire proportional chambers with CsI photo-cathodes have been equipped with a new read-out system based on APV preamplifiers and flash ADC chips. The new system consists of multi-anode photomultiplier tubes (MAPMTs) coupled to individual fused silica lens telescopes, and fast read-out electronics based on the MAD4 amplifier-discriminator and the dead-time free F1 TDC chip. The project was completely designed and implemented in less than two years: The upgraded detector is in operation since the 2006 CERN SPS run. We present the photon detection design, constructive aspects and test studies to characterise the single photon response of the MAPMTs coupled to the read-out system as well as the detector performance based on the 2006 data.

  1. Electric and Magnetic Field-Assisted Orientational Transitions in the Ensembles of Domains in a Nematic Liquid Crystal on the Polymer Surface

    PubMed Central

    Parshin, Alexander M.; Gunyakov, Vladimir A.; Zyryanov, Victor Y.; Shabanov, Vasily F.

    2014-01-01

    Using electro- and magneto-optical techniques, we investigated orientational transitions in the ensembles of domains in a nematic liquid crystal on the polycarbonate film surface under the conditions of competing surface forces that favor radial and uniform planar alignment of nematic molecules. Having analyzed field dependences of the intensity of light passed through a sample, we established the threshold character of the orientational effects, plotted the calculated intensity versus magnetic coherence length, and compared the latter with the equilibrium length that characterizes the balance of forces on the polymer surface. PMID:25279586

  2. A Distinct Layer of the Medulla Integrates Sky Compass Signals in the Brain of an Insect

    PubMed Central

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

    2011-01-01

    Mass migration of desert locusts is a common phenomenon in North Africa and the Middle East but how these insects navigate is still poorly understood. Laboratory studies suggest that locusts are able to exploit the sky polarization pattern as a navigational cue. Like other insects locusts detect polarized light through a specialized dorsal rim area (DRA) of the eye. Polarization signals are transmitted through the optic lobe to the anterior optic tubercle (AOTu) and, finally, to the central complex in the brain. Whereas neurons of the AOTu integrate sky polarization and chromatic cues in a daytime dependent manner, the central complex holds a topographic representation of azimuthal directions suggesting a role as an internal sky compass. To understand further the integration of sky compass cues we studied polarization-sensitive (POL) neurons in the medulla that may be intercalated between DRA photoreceptors and AOTu neurons. Five types of POL-neuron were characterized and four of these in multiple recordings. All neurons had wide arborizations in medulla layer 4 and most, additionally, in the dorsal rim area of the medulla and in the accessory medulla, the presumed circadian clock. The neurons showed type-specific orientational tuning to zenithal polarized light and azimuth tuning to unpolarized green and UV light spots. In contrast to neurons of the AOTu, we found no evidence for color opponency and daytime dependent adjustment of sky compass signals. Therefore, medulla layer 4 is a distinct stage in the integration of sky compass signals that precedes the time-compensated integration of celestial cues in the AOTu. PMID:22114712

  3. A distinct layer of the medulla integrates sky compass signals in the brain of an insect.

    PubMed

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

    2011-01-01

    Mass migration of desert locusts is a common phenomenon in North Africa and the Middle East but how these insects navigate is still poorly understood. Laboratory studies suggest that locusts are able to exploit the sky polarization pattern as a navigational cue. Like other insects locusts detect polarized light through a specialized dorsal rim area (DRA) of the eye. Polarization signals are transmitted through the optic lobe to the anterior optic tubercle (AOTu) and, finally, to the central complex in the brain. Whereas neurons of the AOTu integrate sky polarization and chromatic cues in a daytime dependent manner, the central complex holds a topographic representation of azimuthal directions suggesting a role as an internal sky compass. To understand further the integration of sky compass cues we studied polarization-sensitive (POL) neurons in the medulla that may be intercalated between DRA photoreceptors and AOTu neurons. Five types of POL-neuron were characterized and four of these in multiple recordings. All neurons had wide arborizations in medulla layer 4 and most, additionally, in the dorsal rim area of the medulla and in the accessory medulla, the presumed circadian clock. The neurons showed type-specific orientational tuning to zenithal polarized light and azimuth tuning to unpolarized green and UV light spots. In contrast to neurons of the AOTu, we found no evidence for color opponency and daytime dependent adjustment of sky compass signals. Therefore, medulla layer 4 is a distinct stage in the integration of sky compass signals that precedes the time-compensated integration of celestial cues in the AOTu.

  4. Calculation of susceptibility through multiple orientation sampling (COSMOS): a method for conditioning the inverse problem from measured magnetic field map to susceptibility source image in MRI.

    PubMed

    Liu, Tian; Spincemaille, Pascal; de Rochefort, Ludovic; Kressler, Bryan; Wang, Yi

    2009-01-01

    Magnetic susceptibility differs among tissues based on their contents of iron, calcium, contrast agent, and other molecular compositions. Susceptibility modifies the magnetic field detected in the MR signal phase. The determination of an arbitrary susceptibility distribution from the induced field shifts is a challenging, ill-posed inverse problem. A method called "calculation of susceptibility through multiple orientation sampling" (COSMOS) is proposed to stabilize this inverse problem. The field created by the susceptibility distribution is sampled at multiple orientations with respect to the polarization field, B(0), and the susceptibility map is reconstructed by weighted linear least squares to account for field noise and the signal void region. Numerical simulations and phantom and in vitro imaging validations demonstrated that COSMOS is a stable and precise approach to quantify a susceptibility distribution using MRI.

  5. Conformation and dynamics of melittin bound to magnetically oriented lipid bilayers by solid-state (31)P and (13)C NMR spectroscopy.

    PubMed Central

    Naito, A; Nagao, T; Norisada, K; Mizuno, T; Tuzi, S; Saitô, H

    2000-01-01

    The conformation and dynamics of melittin bound to the dimyristoylphosphatidylcholine (DMPC) bilayer and the magnetic orientation in the lipid bilayer systems were investigated by solid-state (31)P and (13)C NMR spectroscopy. Using (31)P NMR, it was found that melittin-lipid bilayers form magnetically oriented elongated vesicles with the long axis parallel to the magnetic field above the liquid crystalline-gel phase transition temperature (T(m) = 24 degrees C). The conformation, orientation, and dynamics of melittin bound to the membrane were further determined by using this magnetically oriented lipid bilayer system. For this purpose, the (13)C NMR spectra of site-specifically (13)C-labeled melittin bound to the membrane in the static, fast magic angle spinning (MAS) and slow MAS conditions were measured. Subsequently, we analyzed the (13)C chemical shift tensors of carbonyl carbons in the peptide backbone under the conditions where they form an alpha-helix and reorient rapidly about the average helical axis. Finally, it was found that melittin adopts a transmembrane alpha-helix whose average axis is parallel to the bilayer normal. The kink angle between the N- and C-terminal helical rods of melittin in the lipid bilayer is approximately 140 degrees or approximately 160 degrees, which is larger than the value of 120 degrees determined by x-ray diffraction studies. Pore formation was clearly observed below the T(m) in the initial stage of lysis by microscope. This is considered to be caused by the association of melittin molecules in the lipid bilayer. PMID:10777736

  6. Perception of Suffering and Compassion Experience: Brain Gender Disparities

    ERIC Educational Resources Information Center

    Mercadillo, Roberto E.; Diaz, Jose Luis; Pasaye, Erick H.; Barrios, Fernando A.

    2011-01-01

    Compassion is considered a moral emotion related to the perception of suffering in others, and resulting in a motivation to alleviate the afflicted party. We compared brain correlates of compassion-evoking images in women and men. BOLD functional images of 24 healthy volunteers (twelve women and twelve men; age=27 [plus or minus] 2.5 y.o.) were…

  7. Intranasal administration of oxytocin increases compassion toward women.

    PubMed

    Palgi, Sharon; Klein, Ehud; Shamay-Tsoory, Simone G

    2015-03-01

    It has been suggested that the degree of compassion-the feeling of warmth, understanding and kindness that motivates the desire to help others, is modulated by observers' views regarding the target's vulnerability and suffering. This study tested the hypothesis that as compassion developed to protect vulnerable kinships, hormones such as oxytocin, which have been suggested as playing a key role in 'tend-and-befriend' behaviors among women, will enhance compassion toward women but not toward men. Thirty subjects participated in a double-blind, placebo-controlled, within-subject study. Following administration of oxytocin/placebo, participants listened to recordings of different female/male protagonists describing distressful emotional conflicts and were then asked to provide compassionate advice to the protagonist. The participants' responses were coded according to various components of compassion by two clinical psychologists who were blind to the treatment. The results showed that in women and men participants oxytocin enhanced compassion toward women, but did not affect compassion toward men. These findings indicate that the oxytocinergic system differentially mediates compassion toward women and toward men, emphasizing an evolutionary perspective that views compassion as a caregiving behavior designed to help vulnerable individuals.

  8. Evidence for discrete solar and lunar orientation mechanisms in the beach amphipod, Talitrus saltator Montagu (Crustacea, Amphipoda)

    NASA Astrophysics Data System (ADS)

    Ugolini, Alberto; Hoelters, Laura S.; Ciofini, Alice; Pasquali, Vittorio; Wilcockson, David C.

    2016-10-01

    Animals that use astronomical cues to orientate must make continuous adjustment to account for temporal changes in azimuth caused by Earth’s rotation. For example, the Monarch butterfly possesses a time-compensated sun compass dependent upon a circadian clock in the antennae. The amphipod Talitrus saltator possesses both a sun compass and a moon compass. We reasoned that the time-compensated compass mechanism that enables solar orientation of T. saltator is located in the antennae, as is the case for Monarch butterflies. We examined activity rhythms and orientation of sandhoppers with antennae surgically removed, or unilaterally occluded with black paint. Removing or painting the antennae did not affect daily activity rhythms or competence to orientate using the sun. However, when tested at night these animals were unable to orientate correctly to the moon. We subsequently measured circadian gene expression in the antennae and brain of T. saltator and show the clock genes period and cryptochrome 2 are rhythmically expressed in both tissues, reminiscent of other arthropods known to possess antennal clocks. Together, our behavioural and molecular data suggest that, T. saltator has anatomically discrete lunar and solar orientation apparatus; a sun compass, likely located in the brain and a moon compass in the antennae.

  9. Evidence for discrete solar and lunar orientation mechanisms in the beach amphipod, Talitrus saltator Montagu (Crustacea, Amphipoda).

    PubMed

    Ugolini, Alberto; Hoelters, Laura S; Ciofini, Alice; Pasquali, Vittorio; Wilcockson, David C

    2016-10-19

    Animals that use astronomical cues to orientate must make continuous adjustment to account for temporal changes in azimuth caused by Earth's rotation. For example, the Monarch butterfly possesses a time-compensated sun compass dependent upon a circadian clock in the antennae. The amphipod Talitrus saltator possesses both a sun compass and a moon compass. We reasoned that the time-compensated compass mechanism that enables solar orientation of T. saltator is located in the antennae, as is the case for Monarch butterflies. We examined activity rhythms and orientation of sandhoppers with antennae surgically removed, or unilaterally occluded with black paint. Removing or painting the antennae did not affect daily activity rhythms or competence to orientate using the sun. However, when tested at night these animals were unable to orientate correctly to the moon. We subsequently measured circadian gene expression in the antennae and brain of T. saltator and show the clock genes period and cryptochrome 2 are rhythmically expressed in both tissues, reminiscent of other arthropods known to possess antennal clocks. Together, our behavioural and molecular data suggest that, T. saltator has anatomically discrete lunar and solar orientation apparatus; a sun compass, likely located in the brain and a moon compass in the antennae.

  10. Evidence for discrete solar and lunar orientation mechanisms in the beach amphipod, Talitrus saltator Montagu (Crustacea, Amphipoda)

    PubMed Central

    Ugolini, Alberto; Hoelters, Laura S.; Ciofini, Alice; Pasquali, Vittorio; Wilcockson, David C.

    2016-01-01

    Animals that use astronomical cues to orientate must make continuous adjustment to account for temporal changes in azimuth caused by Earth’s rotation. For example, the Monarch butterfly possesses a time-compensated sun compass dependent upon a circadian clock in the antennae. The amphipod Talitrus saltator possesses both a sun compass and a moon compass. We reasoned that the time-compensated compass mechanism that enables solar orientation of T. saltator is located in the antennae, as is the case for Monarch butterflies. We examined activity rhythms and orientation of sandhoppers with antennae surgically removed, or unilaterally occluded with black paint. Removing or painting the antennae did not affect daily activity rhythms or competence to orientate using the sun. However, when tested at night these animals were unable to orientate correctly to the moon. We subsequently measured circadian gene expression in the antennae and brain of T. saltator and show the clock genes period and cryptochrome 2 are rhythmically expressed in both tissues, reminiscent of other arthropods known to possess antennal clocks. Together, our behavioural and molecular data suggest that, T. saltator has anatomically discrete lunar and solar orientation apparatus; a sun compass, likely located in the brain and a moon compass in the antennae. PMID:27759059

  11. The influence of the cutting density on the magnetic properties of non-oriented electrical steels cut through mechanical punching and water jet technologies

    NASA Astrophysics Data System (ADS)

    Paltanea, V.; Paltanea, G.; Gavrila, H.; Popovici, D.; Jiga, G.

    2017-02-01

    The use of high quality non-oriented electrical steel and of an innovative design for the magnetic cores of the electrical machines are very important, in order to minimize the value of the total energy losses. The energy losses are strongly influenced by the cutting technologies, and the producers of the electrical machines want to minimize the deterioration of the magnetic properties during the manufacturing process. The influence of the cutting density on the magnetic permeability and energy losses was analyzed and one can notice that these magnetic properties are strongly influenced by the cutting technologies. There were tested sheet samples of M400-50A and M700-50A industrial steel grades (thickness of 0.50 mm), cut through mechanical and water jet technologies. All samples have the length equal to 300 mm and the width of 30, 15, 10, 7.5 and 5 mm. The magnetic characterization was performed using a laboratory single strip tester, which can make measurements on samples with an area of 300 × 30 mm2. In order to have the standard width of 30 mm, there were put together side by side 2, 3, 4 and 6 pieces with different widths. The magnetic properties were analyzed at 1000 mT in the frequency range 10 ÷ 400 Hz. It was observed that the processing conditions must be controlled and optimized, in order to maintain a low deterioration of the magnetic properties of the non-oriented steels. In the case of water jet technology an increase of the cutting speed will be useful for the introduction of this method in the large scale manufacturing of the electrical machines.

  12. Self-compassion: a novel link with symptoms in schizophrenia?

    PubMed

    Eicher, Amanda C; Davis, Louanne W; Lysaker, Paul H

    2013-05-01

    Self-compassion has been linked to both positive aspects of well-being and less psychopathology in nonclinical samples. Although this construct has begun to be investigated in case studies, the clinical correlates of self-compassion for those with schizophrenia spectrum disorders have yet to be explored. This study aimed to explore the relationship between self-compassion, symptoms, and insight in individuals with schizophrenia. A total of 88 participants with either schizophrenia (n = 51) or schizoaffective disorder (n = 37) who were enrolled in a study of metacognition at a Midwestern Veterans Affairs medical center completed measures of self-compassion and insight, along with a symptom interview. Higher self-compassion scores were associated with lower scores on the Positive and Negative Syndrome Scale positive, excitement, and emotional discomfort symptom scales in addition to poorer insight. Implications for treatment and suggestions for future research are discussed.

  13. A magnetosome chain viewed as a bio-elastic magnet.

    PubMed

    Meyra, Ariel G; Zarragoicoechea, Guillermo J; Kuz, Victor A

    2016-05-14

    In light of the coarse-grained Monte Carlo numerical simulation method, the magnetosome chain stability of magnetotactic bacteria is analysed and discussed. This discrete chain of magnetic nanoparticles, encapsulated in a lipid membrane and flanked by filaments, orients bacteria in the geomagnetic field as a compass needle. Each magnetosome is a magnetite or greigite nanocrystal encapsulated in a soft lipid shell. This structure is modelled by a hard core with a magnetic dipole embedded and a cloud of electric dipoles which are able to move and rotate over the magnetic spherical core. In the present paper, some of the many possibilities of the model by varying the control parameters of the system are explored. Magnetic particles arrange in long linear clusters when the coating is removed. However, linear but twisted chains of magnetic particles emerge when there are electric dipoles in the coating shell. A unique linear and straight chain is not observed in any 3D numerical simulation; this result is in agreement with a real living system of bacteria in a geomagnetic field when proteins that form the filament are absent. Finally, the stability and magnetization of a magnetosome chain of 30 beads in one dimension set up are discussed resembling a real chain. The results suggest that a magnetosome chain not only orients bacteria but also should be considered as a potential storage of elastic energy.

  14. Multi-modal Orientation Cues in Homing Pigeons.

    PubMed

    Walcott, Charles

    2005-06-01

    How homing pigeons displaced into unfamiliar territory find their way home has been the subject of extensive experimentation and debate. One reason for the controversy is that pigeons seem to use multiple cues. Clock-shifting experiments show that experienced pigeons use the sun as a preferred compass; when it is not available they rely on magnetic cues. That pigeons can home successfully while wearing frosted lenses suggests that landmarks, while not an essential navigational cue, are important in the final stages. The sensory basis of the "map" or position finding system is probably equally or even more complicated. When conditions around the loft are suitable, pigeons may use olfactory cues to find their way or might use some feature of the earth's magnetic field for their navigation. The Wiltschkos (1989) showed that pigeons raised without free access to ambient odors are not disoriented when anosmic while their siblings raised with free access to the prevailing wind were disoriented. Similarly, sibling pigeons from two lofts in Lincoln, Massachusetts. were well oriented or totally disoriented when released at magnetic anomalies under sunny skies depending upon which of the two lofts they had been reared in. All of these experiments and many more suggest that pigeons use multiple and redundant cues to find their way home. Further, there is the suggestion that which cues they adopt may well be influenced by the characteristics of the area around the home loft in which they were reared.

  15. Who is at risk for compassion fatigue? An investigation of genetic counselor demographics, anxiety, compassion satisfaction, and burnout.

    PubMed

    Lee, Whiwon; Veach, Patricia McCarthy; MacFarlane, Ian M; LeRoy, Bonnie S

    2015-04-01

    Compassion fatigue is a state of detachment and isolation experienced when healthcare providers repeatedly engage with patients in distress. Compassion fatigue can hinder empathy and cause extreme tension. Prior research suggests 73.8 % of genetic counselors are at moderate to high risk for compassion fatigue and approximately 1 in 4 have considered leaving the field as a result Injeyan et al. (Journal of Genetic Counseling, 20, 526-540, 2011). Empirical data to establish a reliable profile of genetic counselors at risk for compassion fatigue are limited. Thus the purpose of this study was to establish a profile by assessing relationships between state and trait anxiety, burnout, compassion satisfaction, selected demographics and compassion fatigue risk in practicing genetic counselors. Practicing genetic counselors (n = 402) completed an anonymous, online survey containing demographic questions, the State-Trait Anxiety Inventory, and the Professional Quality of Life scale. Multiple regression analysis yielded four significant predictors which increase compassion fatigue risk (accounting for 48 % of the variance): higher levels of trait anxiety, burnout, and compassion satisfaction, and ethnicity other than Caucasian. Additional findings, study limitations, practice implications, and research recommendations are provided.

  16. Electronic and magnetic properties of (1 1 1)-oriented CoCr{sub 2}O{sub 4} epitaxial thin film

    SciTech Connect

    Liu, Xiaoran Kareev, M.; Cao, Yanwei; Middey, S.; Meyers, D.; Chakhalian, J.; Liu, Jian; Freeland, J. W.

    2014-07-28

    We report on the fabrication of high quality (1 1 1)-oriented ferrimagnetic normal spinel CoCr{sub 2}O{sub 4} epitaxial thin films on single crystal Al{sub 2}O{sub 3} substrates. The structural, electronic, and magnetic properties were characterized by in-situ reflection high energy electron diffraction, atomic force microscopy, X-ray diffraction, X-ray photoemission spectroscopy, dc magnetization measurement, and element resolved resonant X-ray magnetic scattering. The comprehensive characterization reveals that no disorder in the cation distribution or multivalency issue is present in the samples. As a result, Kagomé and triangular layers are naturally formed via this specific growth approach. These findings offer a pathway to fabricate two dimensional Kagomé heterostructures with exotic quantum many-body phenomena by means of geometrical design.

  17. On the magnetic anisotropy in Fe78Si9B13 ingots and amorphous ribbons: Orientation aligning of Fe-based phases/clusters

    NASA Astrophysics Data System (ADS)

    Wang, X.; Ma, H. J.; Sheng, Z. H.; Jin, S. F.; Xu, W.; Ferry, M.; Chen, L.; Duan, J. Q.; Wang, W. M.

    2017-01-01

    Magnetic anisotropy in Fe-based amorphous ribbon plays an important role in various applications and is still not fully understood. To gain an in-depth understanding of this phenomenon, the structure and magnetic properties of Fe78Si9B13 master alloy ingots and melt-spun amorphous ribbons were measured by various techniques. For the ingot samples, both the <100>α-Fe and <001>Fe2B axes are aligned parallel with the radial direction (RD) of the original cylindrical ingot, i.e. the maximum temperature gradient direction, and their other orthogonal axes have several preferred directions in the plane vertical to RD. The hard magnetic axis of the ingot samples is parallel to RD, which is due to the large magnetocrystalline anisotropy energy difference between <001> and {001} of the Fe2B phase. For the amorphous ribbons, there is an in-plane magnetic anisotropy: the easy or hard axis of magnetization is aligned on the plane of the ribbon, and parallel to or at an angle of about 60° to its width direction, respectively. According to the structural heredity between the melts and glasses/crystals during solidification, we deduce that the magnetic anisotropy in the ribbon plane is ascribed to the orientation alignment of Fe-Si and Fe-B clusters, i.e. a hidden order beyond short-range order, in Fe78Si9B13 amorphous ribbons.

  18. The role of the crystal orientation (c-axis) on switching field distribution and the magnetic domain configuration in electrodeposited hcp Co-Pt nanowires

    NASA Astrophysics Data System (ADS)

    Shahid Arshad, Muhammad; Proenca, Mariana P.; Trafela, Spela; Neu, Volker; Wolff, Ulrike; Stienen, Sven; Vazquez, Manuel; Kobe, Spomenka; Žužek Rožman, Kristina

    2016-05-01

    In this report, Co-Pt nanowires (NWs) were produced via potentiostatic electrodeposition into commonly used commercial ordered-alumina and disordered-polycarbonate membranes with similar pore diameters (≈200 nm). The pore diameter of the membranes and the deposition conditions were chosen such that the Co-Pt NWs fabricated into both membranes had a hexagonal close packed (hcp) crystal structure with a crystallographic texturing of the c-axis in the direction perpendicular to the NWs’ long axis; this effect was more pronounced in the alumina membranes. Due to the local fluctuation in electrodeposition conditions (pore diameter, pore shape), we have found a small variation in the c-axis orientations in the plane perpendicular to the NWs’ long axis. Magnetic characterizations suggested that there is uniaxial anisotropy perpendicular to the Co-Pt NWs’ long axis and the small variation in the orientation of the hcp c-axis plays an important role in the switching-field distribution and the magnetic domain structure of the Co-Pt NWs. First order reversal curves (FORCs) revealed week magnetostatic interactions between Co-Pt NWs, thus suggesting that the different pore alignments are not influencing much the magnetic properties in both membranes. The micromagnetic simulation revealed that the transverse-stripe (TS) and longitudinal stripe (LS) domains are energetically most favorable structures in such NWs. This study accentuates the influence of the crystal orientation (c-axis) of the high-anisotropy materials on their functional magnetic properties and thus is of great importance for the fabrication of nanodevices based on such NWs.

  19. Light-Meson Spectroscopy at Compass

    NASA Astrophysics Data System (ADS)

    Krinner, Fabian

    2017-03-01

    The goal of the Compass experiment at CERN is to study the structure and spectroscopy of hadrons. The two-stage spectrometer has large acceptance and covers a wide kinematic range for charged as well as neutral particles allowing to access a wide range of reactions. Light mesons are studied with negative (mostly π-) and positive (p, π+) hadron beams with a momentum of 190 GeV/c. The light-meson spectrum is measured in different final states produced in diffractive dissociation reactions with squared four-momentum transfer t to the target between 0.1 and 1.0 (GeV/c)2. The flagship channel is the π-π+π- final state, for which Compass has recorded the currently world's largest data sample. These data not only allow us to measure the properties of known resonances with high precision, but also to search for new states. Among these is a new axial-vector signal, the a1(1420), with unusual properties. The findings are confirmed by the analysis of the π-π0π0 final state.

  20. COMPASS Final Report: Lunar Relay Satellite (LRS)

    NASA Technical Reports Server (NTRS)

    Oleson, Steven R.; McGuire, Melissa L.

    2012-01-01

    The Lunar Relay Satellite (LRS) COllaborative Modeling and Parametric Assessment of Space Systems (COMPASS) session was tasked to design a satellite to orbit in an elliptical lunar polar orbit to provide relay communications between lunar South Pole assets and the Earth. The design included a complete master equipment list, power requirement list, configuration design, and brief risk assessment and cost analysis. The LRS is a half-TDRSS sized box spacecraft, which provides communications and navigation relay between lunar outposts (via Lunar Communications Terminals (LCT)) or Sortie parties (with user radios) and large ground antennas on Earth. The LRS consists of a spacecraft containing all the communications and avionics equipment designed by NASA Jet Propulsion Laboratory s (JPL) Team X to perform the relay between lunar-based assets and the Earth. The satellite design is a standard box truss spacecraft design with a thermal control system, 1.7 m solar arrays for 1 kWe power, a 1 m diameter Ka/S band dish which provides relay communications with the LCT, and a Q-band dish for communications to/from the Earth based assets. While JPL's Team X and Goddard Space Flight Center s (GSFC) I M Design Center (IMDC) have completed two other LRS designs, this NASA Glenn Research Center (GRC) COMPASS LRS design sits between them in terms of physical size and capabilities.