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1

Magnetic compass orientation in the European eel.  

PubMed

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

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

2013-01-01

2

Magnetic Compass Orientation in the European Eel  

PubMed Central

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

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

2013-01-01

3

Orientation of churches by magnetic compasses?  

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

4

A Visual Pathway Links Brain Structures Active during Magnetic Compass Orientation in Migratory Birds  

Microsoft Academic Search

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

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

2007-01-01

5

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

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

6

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

PubMed

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

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

2014-07-01

7

Experiments on orientation recovery and steering of an autonomous mobile robot using encoded magnetic compass disc  

Microsoft Academic Search

This paper describes the experiments on orientation recovery and steering of an autonomous mobile robot which uses an encoded magnetic compass disc as an orientation sensor. The mobile robot developed for experiments in this work is highly cost-effective and has two independent position-sensing systems. The one is an odometric sensor installed on the passive castor wheel, and the other consists

Jae Hwan Kim; Poong Hyun Seong

1996-01-01

8

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

PubMed Central

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. PMID:19889693

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

2010-01-01

9

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...

10

Learned magnetic compass orientation by the Siberian hamster, Phodopus sungorus  

SciTech Connect

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.

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

2003-04-01

11

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

PubMed

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

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

12

Use of a light-dependent magnetic compass for y-axis orientation in European common frog (Rana temporaria) tadpoles.  

PubMed

We provide evidence for the use of a magnetic compass for y-axis orientation (i.e., orientation along the shore-deep water axis) by tadpoles of the European common frog (Rana temporaria). Furthermore, our study provides evidence for a wavelength-dependent effect of light on magnetic compass orientation in amphibians. Tadpoles trained and then tested under full-spectrum light displayed magnetic compass orientation that coincided with the trained shore-deep water axes of their training tanks. Conversely, tadpoles trained under long-wavelength (?500 nm) light and tested under full-spectrum light, and tadpoles trained under full-spectrum light and tested under long-wavelength (?500 nm) light, exhibited a 90° shift in magnetic compass orientation relative to the trained y-axis direction. Our results are consistent with earlier studies showing that the observed 90° shift in the direction of magnetic compass orientation under long-wavelength (?500 nm) light is due to a direct effect of light on the underlying magnetoreception mechanism. These findings also show that wavelength-dependent effects of light do not compromise the function of the magnetic compass under a wide range of natural lighting conditions, presumably due to a large asymmetry in the relatively sensitivity of antagonistic short- and long-wavelength inputs to the light-dependent magnetic compass. PMID:23525820

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

2013-07-01

13

Magnetic compass orientation in two strictly subterranean rodents: learned or species-specific innate directional preference?  

PubMed

Evidence for magnetoreception in mammals remains limited. Magnetic compass orientation or magnetic alignment has been conclusively demonstrated in only a handful of mammalian species. The functional properties and underlying mechanisms have been most thoroughly characterized in Ansell's mole-rat, Fukomys anselli, which is the species of choice due to its spontaneous drive to construct nests in the southeastern sector of a circular arena using the magnetic field azimuth as the primary orientation cue. Because of the remarkable consistency between experiments, it is generally believed that this directional preference is innate. To test the hypothesis that spontaneous southeastern directional preference is a shared, ancestral feature of all African mole-rats (Bathyergidae, Rodentia), we employed the same arena assay to study magnetic orientation in two other mole-rat species, the social giant mole-rat, Fukomys mechowii, and the solitary silvery mole-rat, Heliophobius argenteocinereus. Both species exhibited spontaneous western directional preference and deflected their directional preference according to shifts in the direction of magnetic north, clearly indicating that they were deriving directional information from the magnetic field. Because all of the experiments were performed in total darkness, our results strongly suggest that all African mole-rats use a light-independent magnetic compass for near-space orientation. However, the spontaneous directional preference is not common and may be either innate (but species-specific) or learned. We propose an experiment that should be performed to distinguish between these two alternatives. PMID:22855619

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

2012-10-15

14

Spontaneous magnetic orientation in larval Drosophila shares properties with learned magnetic compass responses in adult flies and mice.  

PubMed

We provide evidence for spontaneous quadramodal magnetic orientation in a larval insect. Second instar Berlin, Canton-S and Oregon-R × Canton-S strains of Drosophila melanogaster exhibited quadramodal orientation with clusters of bearings along the four anti-cardinal compass directions (i.e. 45, 135, 225 and 315 deg). In double-blind experiments, Canton-S Drosophila larvae also exhibited quadramodal orientation in the presence of an earth-strength magnetic field, while this response was abolished when the horizontal component of the magnetic field was cancelled, indicating that the quadramodal behavior is dependent on magnetic cues, and that the spontaneous alignment response may reflect properties of the underlying magnetoreception mechanism. In addition, a re-analysis of data from studies of learned magnetic compass orientation by adult Drosophila melanogaster and C57BL/6 mice revealed patterns of response similar to those exhibited by larval flies, suggesting that a common magnetoreception mechanism may underlie these behaviors. Therefore, characterizing the mechanism(s) of magnetoreception in flies may hold the key to understanding the magnetic sense in a wide array of terrestrial organisms. PMID:23239891

Painter, Michael S; Dommer, David H; Altizer, William W; Muheim, Rachel; Phillips, John B

2013-04-01

15

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

PubMed

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. PMID:11003824

Gudmundsson, G A; Sandberg, R

2000-10-01

16

Magnetic Spinner & Compass  

NSDL National Science Digital Library

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

Watsonville Environmental Science Workshop

2011-01-01

17

A magnetic compass aids monarch butterfly migration.  

PubMed

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

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

2014-01-01

18

A magnetic compass aids monarch butterfly migration  

PubMed Central

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

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

2014-01-01

19

Compasses  

NSDL National Science Digital Library

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

Brieske, Joel A.

2003-01-01

20

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

PubMed Central

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

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

2003-01-01

21

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

PubMed

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

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

2013-08-15

22

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

E-print Network

with the high degree of accuracy in both the map and compass components of homing required to return to woodland. 39, 65--71). Therefore, experiments were carried out to investigate the use of the geomagnetic field The Authors 808 Journal compilation ª 2008 Blackwell Verlag, Berlin #12;scales (e.g., birds and sea turtles

Phillips, John B.

23

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

Microsoft Academic Search

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

Thomas P. Quinn

1980-01-01

24

'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

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 suggestion that homing newts use the light-dependent magnetic compass to align a magnetite-based 'map detector' when obtaining the precise measurements necessary to derive map information from the magnetic field. However, aligning the putative map detector does not explain the fixed-axis response of newts tested under long-wavelength light. Preliminary evidence suggests that, in the absence of reliable directional information from the magnetic compass (caused by the 90 degrees rotation of the response of the magnetic compass under long-wavelength light), newts may resort to a systematic sampling strategy to identify alignment(s) of the map detector that yields reliable magnetic field measurements. PMID:12432012

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

2002-12-01

25

Robins have a magnetic compass in both eyes.  

PubMed

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. PMID:21455128

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

2011-03-31

26

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

ERIC Educational Resources Information Center

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

Crane, H. Richard

1988-01-01

27

Magnetic Orientation in Birds and Other Animals  

Microsoft Academic Search

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

Wolfgang Wiltschko

28

Exploring Magnetic Fields with a Compass  

ERIC Educational Resources Information Center

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…

Lunk, Brandon; Beichner, Robert

2011-01-01

29

A DCM Based Orientation Estimation Algorithm with an Inertial Measurement Unit and a Magnetic Compass  

Microsoft Academic Search

In this paper, Direction Cosine Matrix (DCM) method for attitude and orientation estimation is discussed. DCM method was chosen due to some advantages over the popular methods such as namely Euler Angle, Quaternion in light of reliability, accuracy and computational efforts. Proposed model for each method is developed for methodology comparison. It is shown that normal Kalman Filter in DCM

Ho Quoc Phuong Nguyen; Hee-Jun Kang; Young Soo Suh; Young Shick Ro

2009-01-01

30

46 CFR 108.715 - Magnetic compass and gyrocompass.  

Code of Federal Regulations, 2010 CFR

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

2010-10-01

31

46 CFR 167.40-45 - Magnetic compass and gyrocompass.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Magnetic compass and gyrocompass. 167.40-45...Equipment Requirements § 167.40-45 Magnetic compass and gyrocompass. (a...coastwise service must be fitted with a magnetic compass. (b) All...

2010-10-01

32

Light-Activated Magnetic Compass in Birds  

NASA Astrophysics Data System (ADS)

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.

Solov'yov, Ilia A.; Greiner, Walter

33

Light-dependent magnetic compass in Iberian green frog tadpoles  

NASA Astrophysics Data System (ADS)

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).

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

2010-12-01

34

The magnetic compass of domestic chickens.  

PubMed

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

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

2013-11-01

35

The Light-Dependent Magnetic Compass  

Microsoft Academic Search

Animals can detect different parameters of the geomagnetic field by two principal independent magnetoreception mechanisms:\\u000a (1) a light-dependent process detecting the axial course and the inclination angle of the geomagnetic field lines, providing\\u000a the animals with magnetic compass information (inclination compass), and (2) a magnetite-mediated process, providing magnetic\\u000a map information (map sense). In vertebrates like birds and newts, light-dependent magnetic

Rachel Muheim

36

The magnetic compass of domestic chickens  

PubMed Central

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

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

2013-01-01

37

nCompass Service Oriented Architecture for Tacit Collaboration Services  

Microsoft Academic Search

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 are described from several computational tacit collaboration experiments conducted with open source intelligence analysts

David Schroh; Neil Bozowsky; Mike Savigny; William Wright

2009-01-01

38

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

NASA Astrophysics Data System (ADS)

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

Able, Kenneth P.; Able, Mary A.

1990-09-01

39

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...

40

Tenebrio beetles use magnetic inclination compass  

NASA Astrophysics Data System (ADS)

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.

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

2008-08-01

41

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

Microsoft Academic Search

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

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

2009-01-01

42

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

ERIC Educational Resources Information Center

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

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

43

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

PubMed Central

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

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

1999-01-01

44

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

PubMed

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

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

2013-07-22

45

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

PubMed

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. PMID:22933375

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

2012-10-22

46

Interaction of visual and non-visual cues during migratory orientation by the Bobolink ( Dolichonyx oryzivorus )  

Microsoft Academic Search

Summary The Bobolink appears to use an integrated orientation system involving at least a star compass and a magnetic compass. The magnetic compass appears to provide the primary reference for the system and the star compass serves as a secondary compass. The star compass appears to be checked against the magnetic compass every 1 to 5 nights, and adjusted to

Robert C. Beason

1987-01-01

47

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

PubMed

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

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

2011-08-01

48

Compassion.  

PubMed

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

Saunders, John

2015-04-01

49

Quantum limits for the magnetic sensitivity of a chemical compass  

NASA Astrophysics Data System (ADS)

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

Cai, Jianming; Caruso, Filippo; Plenio, Martin B.

2012-04-01

50

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

PubMed

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

Engels, Svenja; Hein, Christine Maira; Lefeldt, Nele; Prior, Helmut; Mouritsen, Henrik

2012-01-01

51

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

PubMed

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

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

2009-11-01

52

Magnetic Orientation in Birds and Other Animals  

NASA Astrophysics Data System (ADS)

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.

Wiltschko, Wolfgang

53

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

Code of Federal Regulations, 2010 CFR

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

2010-10-01

54

Hatchling sea turtles use surface waves to establish a magnetic compass direction  

PubMed

Hatchling sea turtles emerge from underground nests, crawl to the ocean, and swim away from the land. In shallow water near shore, hatchlings maintain offshore headings by swimming into oceanic waves; in deeper water, however, turtles appear to rely on different mechanisms to maintain their courses. To determine whether loggerhead hatchlings, Caretta caretta L., are able to transfer a course initiated on the basis of waves to a course maintained by a magnetic compass, we studied the orientation behaviour of turtles that had been exposed to waves for either 15 or 30 min before being tested in still water. Hatchlings that swam into waves for 15 min failed to continue swimming on similar courses when the waves were discontinued, but turtles that swam into waves for 30 min maintained similar mean headings after the waves stopped. Inverting the vertical component of the magnetic field during the test period reversed the direction of orientation of this latter group of turtles. Thus, hatchlings can transfer a heading induced by waves to a magnetic compass, and thereby continue to migrate away from land after contact with the coast is lost. Migratory orientation in turtles resembles that of birds in that both rely on multiple cues and an ability to transfer information between various cues and compasses at appropriate times during the journey.Copyright 1998 The Association for the Study of Animal Behaviour. PMID:9480673

Goff; Salmon; Lohmann

1998-01-01

55

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

PubMed

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

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

2009-09-25

56

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

PubMed Central

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

Merlin, Christine; Gegear, Robert J.

2009-01-01

57

Magnetic properties of nanoscale compass-Heisenberg planar clusters  

NASA Astrophysics Data System (ADS)

We study a model of spins 1/2 on a square lattice, generalizing the quantum compass model via the addition of perturbing Heisenberg interactions between nearest neighbors, and investigate its phase diagram and magnetic excitations. This model has motivations both from the field of strongly correlated systems with orbital degeneracy and from that of solid-state based devices proposed for quantum computing. We find that the high degeneracy of ground states of the compass model is fragile and changes into twofold degenerate ground states for any finite amplitude of Heisenberg coupling. By computing the spin structure factors of finite clusters with Lánczos diagonalization, we evidence a rich variety of phases characterized by Z2 symmetry that are either ferromagnetic, C-type antiferromagnetic, or of the Néel type and analyze the effects of quantum fluctuations on phase boundaries. In the ordered phases, the anisotropy of compass interactions leads to a finite excitation gap to spin waves. We show that for small nanoscale clusters with large anisotropy gap the lowest excitations are column-flip excitations that emerge due to Heisenberg perturbing interactions from the manifold of degenerate ground states of the compass model. We derive an effective one-dimensional XYZ model that faithfully reproduces the exact structure of these excited states and elucidates their microscopic origin. The low-energy column-flip or compass-type excitations are robust against decoherence processes and are therefore well designed for storing information in quantum computing. We also point out that the dipolar interactions between nitrogen-vacancy centers forming a rectangular lattice in a diamond matrix may permit a solid-state realization of the anisotropic compass-Heisenberg model.

Trousselet, Fabien; Ole?, Andrzej M.; Horsch, Peter

2012-10-01

58

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

PubMed Central

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

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

2010-01-01

59

Interacting Compasses  

ERIC Educational Resources Information Center

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…

Riveros, Hector G.; Betancourt, Julian

2009-01-01

60

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

Microsoft Academic Search

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

Kenneth P. Able; Mary A. Able

1990-01-01

61

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

Microsoft Academic Search

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

Kenneth P. Able; Mary A. Able

1993-01-01

62

Fuzzy calibration of a magnetic compass for vehicular applications  

NASA Astrophysics Data System (ADS)

In a strapdown compass on a vehicle, three-axis magnetometers measure the Earth's magnetic field vector along the body axes of the vehicle to determine its heading angle. Owing to the local magnetic effects, the measurements frequently deviate from the geomagnetic field vector coordinated in the body frame. Therefore, online calibration of the compass should be considered to satisfy the requirements of the vehicle navigation system. In this paper, a new intelligent method is developed to implement online calibration of the compass system. First, a regression model is proposed to increase the convergence probability of the calibration process using the attitude angles in the measurement equations. Second, based on the knowledge of expert engineers, a Mamdani type fuzzy batch least-square (FBLS) algorithm is designed to estimate the calibration bias and scaling parameters. Generalized likelihood ratio (GLR) and the changes of estimated parameters are considered as the main information of the fuzzy system in which the length of data batch and the associated weighting factor are updated continuously. The results of simulations and experiments reveal the superiority of the proposed approach to the non-fuzzy methods.

Keighobadi, Jafar

2011-08-01

63

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

PubMed

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

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

2015-02-01

64

Magnetic sensitivity and entanglement dynamics of the chemical compass  

NASA Astrophysics Data System (ADS)

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

Kominis, I. K.

2012-07-01

65

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

E-print Network

Sun Compass Orientation by Juvenile Green Sea Turtles (Chelonia mydas) CODY R. MOTT 1 AND MICHAEL [codyrmott@hotmail.com; salmon@fau.edu] ABSTRACT. ­ Juvenile green turtles occupy home ranges on shallow reefs that parallel the southeastern coast of Florida. When disturbed, the turtles often flee eastward

Milton, Sarah

66

Determination of the length and compass orientation of hydraulic fractures by pulse testing  

E-print Network

S3HAIDVHi OIlflVHOAH i0 NOIlVIN3IHO SSVHWOO QNV HlBN31 3Wl iO NOIlVNIWH3l30 DETERMINATION OF THE LENGTH AND COMPASS ORIENTATION OF HYDRAULIC FRACTURES BY PULSE TESTING A Thesis by MADAN MOHAN MANOHAR Approved as to Style and Content by: Wi... liam J. Lee (Ch ai rman of Commi t tee ) Le a M. Je Member) Richard A. Morse (Member) D. Yon Gonten ( d of Department) December 1984 ABSTRACT Determination of the Length and Compass Drientat1on of Hydraulic Fractures by Pulse Testing...

Manohar, Madan Mohan

1984-01-01

67

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

PubMed Central

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

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

1999-01-01

68

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

Microsoft Academic Search

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

Rachel Muheim; Susanne Åkesson; John B. Phillips

2007-01-01

69

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

Microsoft Academic Search

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

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

1999-01-01

70

The quantum compass chain in a transverse magnetic field  

NASA Astrophysics Data System (ADS)

We study the magnetic behaviors of a spin-1/2 quantum compass chain (QCC) in a transverse magnetic field, by means of the analytical spinless fermion approach and numerical Lanczos method. In the absence of the magnetic field, the phase diagram is divided into four gapped regions. To determine what happens by applying a transverse magnetic field, using the spinless fermion approach, critical fields are obtained as a function of exchanges. Our analytical results show, the field-induced effects depend on in which one of the four regions the system is. In two regions of the phase diagram, the Ising-type phase transition happens in a finite field. In another region, we have identified two quantum phase transitions (QPT)s in the ground state magnetic phase diagram. These quantum phase transitions belong to the universality class of the commensurate-incommensurate phase transition. We also present a detailed numerical analysis of the low energy spectrum and the ground state magnetic phase diagram. In particular, we show that the intermediate state (hc1 < h < hc2) is gapful, describing the spin-flop phase.

Motamedifar, M.; Mahdavifar, S.; Farjami Shayesteh, S.

2011-09-01

71

REVIEW THE CASE FOR LIGHT-DEPENDENT MAGNETIC ORIENTATION IN ANIMALS  

Microsoft Academic Search

Light-dependent models of magnetoreception have been proposed which involve an interaction between the magnetic field and either magnetite particles located within a photoreceptor or excited states of photopigment molecules. Consistent with a photoreceptor-based magnetic compass mechanism, magnetic orientation responses in salamanders, flies and birds have been shown to be affected by the wavelength of light. In birds and flies, it

MARK E. DEUTSCHLANDER; JOHN B. PHILLIPS; S. CHRIS BORLAND

72

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

PubMed Central

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

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

2013-01-01

73

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

PubMed

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

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

2013-01-01

74

X-ray compass for determining device orientation  

DOEpatents

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.

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

1999-01-01

75

X-ray compass for determining device orientation  

DOEpatents

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.

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

1999-06-15

76

Research on self-calibration method for tri-axial magnetic compass  

NASA Astrophysics Data System (ADS)

A novel method for the self-calibration of a tri-axial magnetic compass is discussed in this paper. Firstly, the conventional calibration method of tri-axial magnetometer in compass based on ellipsoid fitting is theoretically analyzed, and its weakness is demonstrated. Secondly, an improved calibration scheme for both the magnetometer and accelerometer in a tri-axial magnetic compass is proposed, which utilize the invariance of the dot product of two constant vectors and can overcome the disadvantages of the ellipsoid fitting method. The proposed method is verified by numerical simulation and experiment, and the results prove its superiority over the conventional algorithm of ellipsoid fitting.

Li, Zhi; Li, Xiang

2013-01-01

77

George Biddell Airy and his mechanical correction of the magnetic compass  

Microsoft Academic Search

George Biddell Airy (1801–1892) invented the first successful mechanical system of compass correction in 1838, at a time when iron ship-building, especially for steam-driven vessels, had become firmly established. One serious drawback to iron ships was the difficulty in the management of the magnetic compass on board due to the magnetic condition of the ship. The introduction to this paper,

Charles H. Cotter

1976-01-01

78

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

PubMed Central

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

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

2013-01-01

79

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

PubMed

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

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

2014-08-01

80

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

PubMed

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

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

2012-01-01

81

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

PubMed Central

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

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

2014-01-01

82

Freely oriented portable superconducting magnet  

DOEpatents

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.

Schmierer, Eric N. (Los Alamos, NM); Prenger, F. Coyne (Los Alamos, NM); Hill, Dallas D. (Los Alamos, NM)

2010-01-12

83

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

PubMed

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

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

2013-09-01

84

Quantum Probe and Design for a Chemical Compass with Magnetic Nanostructures  

NASA Astrophysics Data System (ADS)

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.

Cai, Jianming

2011-03-01

85

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

PubMed

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

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

2013-06-01

86

Teaching Basic Geographical Skills: Map and Compass Activities.  

ERIC Educational Resources Information Center

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)

Trussell, Margaret Edith

1986-01-01

87

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

PubMed

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

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

2015-01-15

88

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

PubMed Central

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

Wyeth, Russell C.

2010-01-01

89

Magnetic compasses in biological systems: Does quantum physics play a role?  

NASA Astrophysics Data System (ADS)

One hypothesis of the process underlying the magnetic compass of animals surmises that the magnetic field is perceived by its effect on the coherent spin evolution within a non-equilibrium photochemical radical pair reaction. If this hypothesis were proven, it would be a dramatic demonstration of a quantum process with clear biological significance. We will review the physics of the radical pair mechanism and the current state of evidence supporting it. Experimentally, we will focus on the use radio-frequency magnetic fields to affect a radical-pair based mechanism in birds and discuss the approach and its limitations. Theoretically, we will focus on the question of how one should design a radical pair to be optimally sensitive to the direction of a weak magnetic field. Regardless of whether or not a radical pair mechanism is indeed used by birds or other animals, optimal design features could be used to manufacture biologically inspired, but man-made magnetic compass systems.

Ritz, Thorsten

2011-03-01

90

Orientation and Magnitude of Mars' Magnetic Field  

NASA Technical Reports Server (NTRS)

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).

1997-01-01

91

The Relationship between Transformational Leadership and Customer-Oriented Boundary-Spanning Behaviours: Examining the Role of Compassion  

Microsoft Academic Search

Customer-oriented boundary-spanning behaviours (COBSBs) are critical to the success of service organisations. Transformational leadership, with its emphasis on the social elements of the leader-subordinate dyad, is a likely antecedent to COBSBs. Similarly, the interpersonal nature of services suggests leader compassion could have a significant effect on the saliency of the relationship between transformational leadership and COBSBs. This paper reports on

Anne L Souchon; Geoffrey R Durden

92

Create a Compass  

NSDL National Science Digital Library

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

93

Interactions in the flexible orientation system of a migratory bird  

Microsoft Academic Search

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

Kenneth P. Able; Mary A. Able

1995-01-01

94

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

PubMed Central

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

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

2010-01-01

95

Numerous behavioral experiments have demonstrated that animals use the Earth's magnetic field as a directional cue  

E-print Network

magnetic orientation behavior remain poorly understood. The marine mollusc Tritonia diomedea is a promising underlying magnetic orientation behavior. The marine mollusc Tritonia diomedea has both a magnetic compass, magnetoreception, orientation, navigation, mollusc. Summary Introduction Identifiable neurons inhibited by Earth

Lohmann, Kenneth J.

96

Freely Oriented, Portable Superconducting Magnet  

NASA Astrophysics Data System (ADS)

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

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

2008-03-01

97

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

PubMed

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. PMID:21865522

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

2011-09-15

98

46 CFR 121.402 - Compasses.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Compasses. 121.402 Section 121...Navigation Equipment § 121.402 Compasses. (a) Except as otherwise...must be fitted with a suitable magnetic compass designed for marine use,...

2010-10-01

99

Dancing Compasses  

NSDL National Science Digital Library

Learners use compasses to detect the magnetic field created by current moving through a wire. This is one of four activities learners can complete related to PhysicsQuest 2008. Each activity gives a clue to solve a puzzle in the accompanying comic book, "Nikola Tesla and the Electric Fair."

American Physical Society

2009-01-01

100

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

PubMed

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

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

2001-09-22

101

Antennal Circadian Clocks Coordinate Sun Compass Orientation in Migratory Monarch Butterflies  

Microsoft Academic Search

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

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

2009-01-01

102

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

103

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

E-print Network

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

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

2014-09-20

104

Chinese tombs oriented by a compass: Evidence from paleomagnetic changes versus the age of tombs  

Microsoft Academic Search

Extant written records indicate that knowledge of an ancient type of compass in China is very old — dating back to before\\u000a the Han dynasty (206 BC-220 AD) to at least the 4th century BC. Geomancy (feng shui) was practised for a long time (for millenia)\\u000a and had a profound influence on the face of China’s landscape and city plans.

Ivanka Charvátová; Jaroslav Kloko?ník; Josef Kolmaš; Jan Kostelecký

2011-01-01

105

Magnetic orientation of sphingomyelin-lecithin bilayers.  

PubMed Central

Phospholipid bilayers consisting of a 60:40 mixture of N-palmitoylsphingomyelin and dimyristoylphosphatidylcholine orient in a strong magnetic field. The orientation is easily observed in 31P- and 2H-nuclear magnetic resonance spectra where the intensity of the perpendicular edges of the powder lineshapes are enhanced. The lineshapes indicate that the long axis of the molecule is perpendicular to the magnetic field. PMID:3580492

Speyer, J B; Sripada, P K; Das Gupta, S K; Shipley, G G; Griffin, R G

1987-01-01

106

Protein crystals orientation in a magnetic field.  

PubMed

Nucleation and crystal growth of hen egg-white lysozyme, bovine pancreatic trypsin inhibitor and porcine pancreatic alpha-amylase were carried out in the presence of a magnetic field of 1.25 T produced by small permanent magnets. Crystals were oriented in the magnetic field, except when heterogeneous nucleation occurred. The orientation of protein crystals in the presence of a magnetic field can be attributed to the anisotropic diamagnetic susceptibility of proteins resulting from the large anisotropy of the alpha-helices due to the axial alignment of the peptide bonds. PMID:9761881

Astier, J P; Veesler, S; Boistelle, R

1998-07-01

107

Magnetic orientation and magnetoreception in birds and other animals.  

PubMed

Animals use the geomagnetic field in many ways: the magnetic vector provides a compass; magnetic intensity and/or inclination play a role as a component of the navigational 'map', and magnetic conditions of certain regions act as 'sign posts' or triggers, eliciting specific responses. A magnetic compass is widespread among animals, magnetic navigation is indicated e.g. in birds, marine turtles and spiny lobsters and the use of magnetic 'sign posts' has been described for birds and marine turtles. For magnetoreception, two hypotheses are currently discussed, one proposing a chemical compass based on a radical pair mechanism, the other postulating processes involving magnetite particles. The available evidence suggests that birds use both mechanisms, with the radical pair mechanism in the right eye providing directional information and a magnetite-based mechanism in the upper beak providing information on position as component of the 'map'. Behavioral data from other animals indicate a light-dependent compass probably based on a radical pair mechanism in amphibians and a possibly magnetite-based mechanism in mammals. Histological and electrophysiological data suggest a magnetite-based mechanism in the nasal cavities of salmonid fish. Little is known about the parts of the brain where the respective information is processed. PMID:15886990

Wiltschko, Wolfgang; Wiltschko, Roswitha

2005-08-01

108

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

109

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

PubMed

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 fitness of this dominant pollinator might be affected by RF fields. The goal of this review is to provide an overview of the path that the behavioral research on honeybee magnetoreception has taken and to discuss it in the context of contemporary data obtained on other insects. PMID:22313997

Válková, T; Vácha, M

2012-08-01

110

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

PubMed

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

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

2013-11-01

111

Compact Optoelectronic Compass  

NASA Technical Reports Server (NTRS)

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

Christian, Carl

2004-01-01

112

Superconducting magnet for nuclei orientation  

E-print Network

. Introduction . . . . . ~ ~ ~ ~ ~ ~ ~ ~ II. Superconducting Magnet 1 ~ Superconductivity and Super- conliuc'tore ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 3 2. Superconducting Solenoid Model 1 ~ ~ o ~ e ~ o ~ ~ ~ ~ ~ ~ eoe ~ ~ o ~ oeo 1Q Superconducting... drops suddenly to zero when the specimen is cooled down to a sufficiently: low temperature. Another dramat1c property exhibited by a super- conductor is a magnetic property. It 1s an experi- mental fact that when a bulk specimen is placed in a weak...

Wang, Fa-Chung

1968-01-01

113

Self-Compassion in Iranian Muslims: Relationships With Integrative Self-Knowledge, Mental Health, and Religious Orientation  

Microsoft Academic Search

Although a Buddhist construct, self-compassion may have implications for understanding psychological adjustment cross-culturally. In Iranian Muslims, the Self-Compassion Scale correlated positively with integrative self-knowledge, self-esteem, and basic need satisfactions and negatively with depression and anxiety. Negative linkages with depression and anxiety continued to appear in partial correlations controlling for self-esteem, replicating a result previously observed in the United States. Integrative

Nima Ghorbani; P. J. Watson; Zhuo Chen; Fatemeh Norballa

2012-01-01

114

Compass models: Theory and physical motivations  

NASA Astrophysics Data System (ADS)

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

Nussinov, Zohar; van den Brink, Jeroen

2015-01-01

115

Magnetic orientation of respirable asbestos fibers  

NASA Astrophysics Data System (ADS)

Exposure to contaminated atmospheres is now strictly controlled and control limits have been delineated, giving maximum permissible concentrations of airborne fibers. These limits depend on the type of asbestos as well as concentration. Unfortunately, the current analytical technique cannot distinguish between different types of asbestos fibers or differentiate between asbestos and nonasbestos fibers of respirable size. In the current work orientations of amosite, chrysotile, and crocidolite have been measured as functions of magnetic field strength. Results show the family to have different orientation characteristics, and markedly different field strengths are required to align the various fibers. The results would indicate that a magnetic orientation technique can be used to distinguish between respirable asbestos and nonasbestos fibers and also to differentiate between the main types of asbestos fibers.

Willey, R. J.

1987-04-01

116

Sensitivity and entanglement in the avian chemical compass  

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

117

Sensitivity and entanglement in the avian chemical compass.  

PubMed

The radical pair mechanism can help to explain avian orientation and navigation. Some evidence indicates that the intensity of external magnetic fields plays an important role in avian navigation. In this paper, using a two-stage model, we demonstrate that birds could reasonably detect the directions of geomagnetic fields and gradients of these fields using a yield-based chemical compass that is sensitive enough for navigation. Also, we find that the lifetime of entanglement in this proposed compass is angle dependent and long enough to allow adequate electron transfer between molecules. PMID:25375523

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

2014-10-01

118

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)

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 precision of these humpback whale track segments is far better than the ±25°-40° precision of the avian magnetic compass. The positional and directional orientation data presented suggests signal transduction provides spatial information to migrating animals with better than 1° precision.

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

2010-12-01

119

Trough Compass with Case, 1916  

USGS Multimedia Gallery

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

120

Bats Use Magnetite to Detect the Earth's Magnetic Field  

Microsoft Academic Search

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 (Fe3O4). Bats have recently been shown to use magnetic

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

2008-01-01

121

Bats Use Magnetite to Detect the Earth's Magnetic Field  

Microsoft Academic Search

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 (Fe3O4). Bats have recently been shown to use magnetic

Richard A. Holland; Joseph L. Kirschvink; Thomas G. Doak; Martin Wikelski; Sarah Frances Brosnan

2008-01-01

122

Magnetic clouds orientations using minimum variance analysis  

NASA Astrophysics Data System (ADS)

Magnetic clouds (MCs) at 1 AU present distinctive characteristics from the surrounding solar wind. The minimum variance (MV) technique applied to a temporal series of magnetic data observed on a satellite trajectory can find the orientation of the principal axis very well when the distance to the cloud axis (i. e. impact parameter, p) is negligible; when this is not the case the direct application of this technique can be questionable. In this work we generate a set of synthetic clouds with different orientations and p. These clouds are modeled assuming local cylindrical symmetry and a linear force free field for their magnetic configuration. Our goal is to treat the magnetic field values of these synthetic clouds as if they were data observed by a satellite, and estimate the error that the direct application of MV introduces when p is not small. These results are useful to improve the estimations of global magneto-hydrodynamic magnitudes in interplanetary magnetic clouds. FULL TEXT IN SPANISH

Gulisano, A. M.; Dasso, S.; Mandrini, C. H.; D'Emoulin, P.

123

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

PubMed

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

Able; Able

1996-01-01

124

Spontaneous preferences for magnetic compass direction in the American red-spotted newt, Notophthalmus viridescens (Salamandridae, Urodela)  

Microsoft Academic Search

In addition to other sensory modalities, migratory vertebrates are able to use the earths’ magnetic field for orientation\\u000a and navigation. The magnetic cue may also serve as a reference for other orientation mechanisms. In this study, significant\\u000a evidence is shown that, even in darkness, newts (Notophthalmus viridescens, Salamandridae) spontaneously align according to the natural or to the deviated earth’s magnetic

Peter A. Schlegel

2007-01-01

125

Self-compassion and social anxiety disorder.  

PubMed

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. PMID:21895450

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

2012-01-01

126

Navigating the Earth with a Compass  

NSDL National Science Digital Library

This lesson is an introduction to the use of a magnetic compass. At a specific location, learners will locate an object using a compass, identify its bearing, and others will attempt to locate the object by only knowing the bearing reading and the corresponding location where the bearing was obtained. Next, learners will develop a method for determining if a magnetic storm is occurring, and they will test this method using online information and a compass. This activity requires compasses and access to the Internet. This is Activity 5 in the Exploring Magnetism on Earth teachers guide.

2012-08-03

127

Self-compassion and social anxiety disorder  

Microsoft Academic Search

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,

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

2011-01-01

128

Self-compassion and social anxiety disorder  

Microsoft Academic Search

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,

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

2012-01-01

129

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

USGS Publications Warehouse

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, providing evidence that navigation may share a common basis in different vertebrate groups.

Rodda, Gordon H.

1984-01-01

130

The sun compass revisited  

PubMed Central

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

Guilford, Tim; Taylor, Graham K.

2014-01-01

131

Compassion: An Evolutionary Analysis and Empirical Review  

PubMed Central

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

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

2010-01-01

132

Finding Your Way with Map and Compass  

NSDL National Science Digital Library

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

2001-03-01

133

Design of a data acquisition system on magnetic signal for magnetic localization and orientation system  

Microsoft Academic Search

The location and orientation of the wireless capsule endoscope inside the human body is very important for the gastrointestinal (GI) examination. To satisfy the requirement of the position and gesture information of endoscope, a magnetic localization and orientation system is built. The system uses a permanent magnet as excitation source to create the magnetic field, and consists of a magnetic

Jiayu Ren; Mao Li; Chao Hu; Lin Yang; Shuang Song; Max Q.-H. Meng

2010-01-01

134

Remotely readable fiber optic compass  

DOEpatents

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.

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

1986-01-01

135

Remotely readable fiber optic compass  

DOEpatents

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.

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

1985-04-30

136

Computational modeling of magnetically actuated propellant orientation  

NASA Technical Reports Server (NTRS)

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 spacecraft propellant tanks: magnetic fields.

Hochstein, John I.

1996-01-01

137

An fMRI study of caring vs self-focus during induced compassion and pride  

PubMed Central

This study examined neural activation during the experience of compassion, an emotion that orients people toward vulnerable others and prompts caregiving, and pride, a self-focused emotion that signals individual strength and heightened status. Functional magnetic resonance images (fMRI) were acquired as participants viewed 55?s continuous sequences of slides to induce either compassion or pride, presented in alternation with sequences of neutral slides. Emotion self-report data were collected after each slide condition within the fMRI scanner. Compassion induction was associated with activation in the midbrain periaqueductal gray (PAG), a region that is activated during pain and the perception of others’ pain, and that has been implicated in parental nurturance behaviors. Pride induction engaged the posterior medial cortex, a region that has been associated with self-referent processing. Self-reports of compassion experience were correlated with increased activation in a region near the PAG, and in the right inferior frontal gyrus (IFG). Self-reports of pride experience, in contrast, were correlated with reduced activation in the IFG and the anterior insula. These results provide preliminary evidence towards understanding the neural correlates of important interpersonal dimensions of compassion and pride. Caring (compassion) and self-focus (pride) may represent core appraisals that differentiate the response profiles of many emotions. PMID:21896494

Godzik, Jakub; Castle, Elizabeth; Antonenko, Olga; Ponz, Aurelie; Kogan, Aleksander; Keltner, Dacher J.

2012-01-01

138

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

E-print Network

photoreceptors located in or near the pineal organ, and here we present new findings that indicate that the putative long- wavelength mechanism is also associated with pineal photoreceptors. Interestingly, the amphibian pineal organ mediates orientation to both the e-vector of plane- polarized light and the magnetic

Phillips, John B.

139

Create a Compass  

NSDL National Science Digital Library

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

2012-06-26

140

INTERMAG 2006 595 A Magnetically Excited And Sensed MEMS-Based Resonant Compass.  

E-print Network

micromachined resonator incorporating a permanent magnet. It exhibited very low power consumption. In this paper, we report an all-magnetic MEMS-based resonant com- pass, driven electromagnetically consists of a permanent magnet torsionally supported on a resonant MEMS disc. The interaction between

141

Compensation of magnetic disturbances improves inertial and magnetic sensing of human body segment orientation  

Microsoft Academic Search

This paper describes a complementary Kalman filter design to estimate orientation of human body segments by fusing gyroscope, accelerometer, and magnetometer signals from miniature sensors. Ferromagnetic materials or other magnetic fields near the sensor module disturb the local earth magnetic field and, therefore, the orientation estimation, which impedes many (ambulatory) applications. In the filter, the gyroscope bias error, orientation error,

Daniel Roetenberg; Henk J. Luinge; Chris T. M. Baten; Peter H. Veltink

2005-01-01

142

The cricket compass for context-aware mobile applications  

Microsoft Academic Search

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

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

2001-01-01

143

The development of migratory orientation mechanisms.  

PubMed

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

Able, K P

1991-01-01

144

Control of magnetization reversal in oriented strontium ferrite thin films  

SciTech Connect

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.

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

2014-02-21

145

Magnetic Position and Orientation Tracking System  

Microsoft Academic Search

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

Frederick Raab; Ernest Blood; Terry Steiner; Herbert Jones

1979-01-01

146

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

Microsoft Academic Search

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

I. R. Caldwell; V. O. Nams

2006-01-01

147

General Orientation Syllabus Fields and Galois Theory Ruler and Compass Constructions Galois Theory Assignment Math 552: Abstract Algebra II  

E-print Network

Rings · Structure of Artinian Rings · The X-Topic #12;General Orientation Syllabus Fields and Galois Assignment Syllabus Math 552 Course description. It follows the same organization as the current Math 551.com or other websites. In the fall, photocopies will be available for purchase. Prerequisites: Any standard

Vasconcelos, Wolmer

148

The Cricket Compass for ContextAware Mobile Applications  

E-print Network

The Cricket Compass for Context­Aware Mobile Applications Nissanka B. Priyantha, Allen K. L. Miu,aklmiu,hari,seth}@lcs.mit.edu http://nms.lcs.mit.edu/cricket/ Abstract The ability to determine the orientation of a device compass, knowledge of orientation through the Cricket com- pass attached to a mobile device enhances

149

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

PubMed

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

Cai, Jianming; Plenio, Martin B

2013-12-01

150

Chemical Compass Model for Avian Magnetoreception as a Quantum Coherent Device  

NASA Astrophysics Data System (ADS)

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.

Cai, Jianming; Plenio, Martin B.

2013-12-01

151

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

PubMed

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

Sandberg; Pettersson

1996-01-01

152

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

E-print Network

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 o...

Zhang, Yiteng; Kais, Sabre

2015-01-01

153

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...

154

Aircraft compass characteristics  

NASA Technical Reports Server (NTRS)

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.

Peterson, John B; Smith, Clyde W

1937-01-01

155

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

NASA Astrophysics Data System (ADS)

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.

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

2005-05-01

156

The Orientation of the Local Interstellar Magnetic Field  

E-print Network

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

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

2007-05-13

157

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

ERIC Educational Resources Information Center

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…

Dean, J.; Allwood, D. A.

2014-01-01

158

A Magnetite Null Detector as the Migrating Bird's Compass  

Microsoft Academic Search

The magnetic compass of migrating birds is different from a normal terrestrial compass in that reversing the direction of the magnetic field leaves its reading unchanged. The birds detect the north-south plane as that containing the directions of the earth's magnetic field and gravity, and for north-south discrimination, and also possibly for a map sense of latitude, they detect the

D. T. Edmonds

1992-01-01

159

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

Microsoft Academic Search

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

A. N. Zakhlevnykh; P. A. Sosnin

1994-01-01

160

Finding Your Way with Map and Compass  

NSDL National Science Digital Library

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

161

From compass to hard drive—integrated activities for studying magnets  

NASA Astrophysics Data System (ADS)

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

Dean, J.; Allwood, D. A.

2014-11-01

162

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

PubMed

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

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

2014-12-01

163

Angular dependence of dynamic magnetic properties and magnetization orientation distribution of thin films  

SciTech Connect

The angular dependence of dynamic magnetic properties of FeTaN thin films fabricated by rf sputtering deposition technique onto various substrates was investigated in conjunction with static magnetic characteristics. Thin films grown onto rigid and thick substrates show a well-defined uniaxial anisotropy and strongly distinct permeability spectra measured at various orientations while those samples grown onto flexible and thin substrates exhibit a less well-defined uniaxial anisotropy and much less different permeability spectra. The resultant variation of the magnetization orientation distributions obtained by retrieving the magnetization values from the permeability curves for different substrates can be interpreted in terms of the magnetic anisotropy dispersion due to stress.

Hung, Le Thanh; Ong, C. K. [Department of Physics, Center for Superconducting and Magnetic Materials, National University of Singapore, 2 Science Drive3, Singapore 117542 (Singapore); Phuoc, Nguyen N. [Temasek Laboratories, National University of Singapore, 5A Engineering Drive 2, Singapore 117411 (Singapore)

2009-09-15

164

Stress fiber contributes to rat Schwann cell orientation under magnetic field  

Microsoft Academic Search

This paper examines the role of cytoskeletons, such as stress fibers, on magnetic orientation of Schwann cells after strong magnetic field exposure (8-T in maximum). Schwann cells were cultured from dissected sciatic nerves of neonatal rats. Schwann cells oriented parallel to the magnetic field after 60 h of more than 4-T magnetic field exposure. Actin fibers oriented in the direction

Yawara Eguchi; Shoogo Ueno

2005-01-01

165

Modeling of particles orientation in magnetic field in drying magnetic coatings  

Microsoft Academic Search

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.

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

2000-01-01

166

Unambiguous position and orientation tracking using a rotating magnet  

NASA Astrophysics Data System (ADS)

We present a measurement system for magnetic position and orientation tracking. It uses a rotating magnet as transmitter and a three-axis magnetic field sensor to measure the magnetic field ellipse produced by the magnet. A theory is given for the calculation of the magnet's position and orientation from the ellipse's semi-axis components. Detection range and accuracy of the tracking method and their dependence on magnetic moment, noise levels of the environment, and the sensor type are shown. Using a fluxgate sensor, which is the best choice for a typical urban environment, a NdFeB magnet with a volume of about 180 cm3 can be detected with 1% error up to 17 m distance. With the use of two moderately distant identical sensors and an adequate evaluation of the tracking components' evolution, the right one out of four possible solutions as delivered by the tracking algorithm can be reliably chosen, independent of the tracking course. This way, a unique solution of the three-dimensional inverse problem can be achieved.

Schultze, Volkmar; Andrä, Wilfried; Peiselt, Katja; Gleichmann, Nils; Meyer, Hans-Georg

2013-09-01

167

ORIGINAL PAPER Magnetic orientation by hatchling loggerhead sea turtles  

E-print Network

ORIGINAL PAPER Magnetic orientation by hatchling loggerhead sea turtles (Caretta caretta) from Springer-Verlag 2010 Abstract Loggerhead sea turtle hatchlings emerge from nests on either the east or west behaviorally by their fidelity to different rookery sites (Bjorndal et al. 1983; LeBuff 1990; Tucker 2010

Milton, Sarah

168

Accurate Orientation Estimation Using AHRS under Conditions of Magnetic Distortion  

PubMed Central

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

Yadav, Nagesh; Bleakley, Chris

2014-01-01

169

Accurate orientation estimation using AHRS under conditions of magnetic distortion.  

PubMed

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

Yadav, Nagesh; Bleakley, Chris

2014-01-01

170

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

PubMed Central

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

Alerstam, T; Gudmundsson, GA

1999-01-01

171

Are migrating raptors guided by a geomagnetic compass?  

USGS Publications Warehouse

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.

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

2006-01-01

172

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

E-print Network

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.

Yiteng Zhang; Gennady P. Berman; Sabre Kais

2015-02-02

173

Experimental evidence for a magnetic sense in Neotropical migrating butterflies (Lepidoptera: Pieridae)  

Microsoft Academic Search

We tested whether migrating Aphrissa statira butterflies orient with a magnetic compass. We captured mi- grants flying over Lake Gatun, Panama, and exposed experimental butterflies to a strong magnetic field. These and unmanipulated control butterflies were released back over the lake. Experimental butterflies had a more dispersed pattern of orientation than control butterflies. The average direction adopted was northeast, 160

Robert B. Srygley; Robert Dudley; Evandro G. Oliveira; Andre J. Riveros

2006-01-01

174

FEA Simulations of Magnets with Grain Oriented Steel  

SciTech Connect

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.

Witte H.

2012-08-06

175

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...

176

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

NASA Astrophysics Data System (ADS)

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.

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

2014-11-01

177

True North, Magnetic North  

NSDL National Science Digital Library

This activity helps students understand why compass angles need to be corrected for regional magnetic variation. The magnetic compass, perfected slowly over years of experimentation, trial, and scientific endeavor, became the sailor's most common and most reliable direction-indicating aid, but is influenced by magnetic variabilities and the location of magnetic north. Terms introduced include compass, magnetic variation, true north, and magnetic north.

178

Micromotors with built-in compasses.  

PubMed

We demonstrate here that iron containing rolled-up microtubular engines can be magnetized and act as compass needles - they sense the direction of an external magnetic field from afar and align the directionalities of their movements according to the external field, in a similar fashion to magnetotactic bacteria. PMID:22955117

Zhao, Guanjia; Sanchez, Samuel; Schmidt, Oliver G; Pumera, Martin

2012-10-18

179

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

PubMed Central

Background Zebra finches can be trained to use the geomagnetic field as a directional cue for short distance orientation. The physical mechanisms underlying the primary processes of magnetoreception are, however, largely unknown. Two hypotheses of how birds perceive magnetic information are mainly discussed, one dealing with modulation of radical pair processes in retinal structures, the other assuming that iron deposits in the upper beak of the birds are involved. Oscillating magnetic fields in the MHz range disturb radical pair mechanisms but do not affect magnetic particles. Thus, application of such oscillating fields in behavioral experiments can be used as a diagnostic tool to decide between the two alternatives. Methods In a setup that eliminates all directional cues except the geomagnetic field zebra finches were trained to search for food in the magnetic north/south axis. The birds were then tested for orientation performance in two magnetic conditions. In condition 1 the horizontal component of the geomagnetic field was shifted by 90 degrees using a helmholtz coil. In condition 2 a high frequently oscillating field (1.156 MHz) was applied in addition to the shifted field. Another group of birds was trained to solve the orientation task, but with visual landmarks as directional cue. The birds were then tested for their orientation performance in the same magnetic conditions as applied for the first experiment. Results The zebra finches could be trained successfully to orient in the geomagnetic field for food search in the north/south axis. They were also well oriented in test condition 1, with the magnetic field shifted horizontally by 90 degrees. In contrast, when the oscillating field was added, the directional choices during food search were randomly distributed. Birds that were trained to visually guided orientation showed no difference of orientation performance in the two magnetic conditions. Conclusion The results indicate that zebra finches use a receptor that bases on radical pair processes for sensing the direction of the earth magnetic field in this short distance orientation behavior. PMID:19852792

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

2009-01-01

180

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

PubMed Central

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

Helduser, Sascha; Mouritsen, Henrik; Güntürkün, Onur

2015-01-01

181

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

PubMed

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

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

2015-01-01

182

Large coercive field in magnetic-field oriented ?-Fe 2O 3 nanorods  

Microsoft Academic Search

We report the fabrication and magnetic coercive field of oriented ?-Fe2O3 nanorods. Oriented ?-Fe2O3 nanorods embedded in SiO2 matrix were obtained by a sol–gel method under an applied external magnetic field. The longitudinal axis, which corresponds to a-axis of the crystal structure of ?-Fe2O3 nanorods, was oriented parallel to the direction of external magnetic field. The sample achieved a magnetic

Shunsuke Sakurai; Jun-ichi Shimoyama; Kazuhito Hashimoto; Shin-ichi Ohkoshi

2008-01-01

183

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

PubMed Central

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

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

2015-01-01

184

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

PubMed

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

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

2014-01-01

185

Determining the axis orientation of cylindrical magnetic flux rope  

NASA Astrophysics Data System (ADS)

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.

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

2013-04-01

186

A Method to Verify Accuracy of Predicted Magnetic Orientation of a Permanent Ring Magnet in a Brushless DC Motor  

Microsoft Academic Search

The paper reports a numerical and experimental method to verify the predicted magnetic orientation of a permanent ring magnet before the magnet is assembled into a brushless DC (BLDC) motor. A simple magnetic configuration, in which a permanent magnet is placed in the air without presence of any large permeability material in the vicinity, is proposed to eliminate changes in

Taeyong Yoon; Dennis K. Lieu

2007-01-01

187

Anisotropy study of grain oriented steels with Magnetic Barkhausen Noise  

NASA Astrophysics Data System (ADS)

Grain oriented electrical steels present strong anisotropy, due to a {110} <001> texture (Goss), with [100] direction parallel to rolling direction (RD) and [110] direction parallel to transverse direction (TD). MBN (Magnetic Barkhausen Noise) were employed to measure magnetic properties in several angles towards RD using a 15° step. For 90° to the rolling direction (i.e., TD), the MBN signal changes, decreasing the MBNrms. It is found a connection between initial permeability and MBNrms. The lower initial permeability for the TD is related to a larger contribution of irreversible rotation in the hysteresis. The MBN procedure is non-destructive and provides rapid understanding of the anisotropy of the material, without the use of laborious methods like Epstein frame or toroidal coils.

de Campos, M. F.; Campos, M. A.; Landgraf, F. J. G.; Padovese, L. R.

2011-07-01

188

Magnetosheath parameter profiles under different magnetic field orientations  

NASA Astrophysics Data System (ADS)

We used 6-year Themis measurements of plasma and magnetic field parameters in the magnetosheath and constructed a map of their averaged values. To creation of map profiles, the Jelinek et al. (2012) model of both the bow shock and magnetopause was applied. We present the changes of the magnetosheath spatial profiles under various interplanetary magnetic field orientations. An advantage of the procedure is that the same spacecraft measurements were used for construction of model boundaries and for determination of averaged profiles of plasma parameters and that our large data set includes one-half of solar cycle. Moreover, we compare profiles of the plasma density, velocity and temperature with those obtained from the Spreiter et al. (1966) and MHD (BATS-R-US) models. We discuss deviations between experimental and predicted profiles for different conditions along one-half solar cycle.

Jelinek, Karel; Nemecek, Zdenek; Safrankova, Jana; Samsonov, Andrey

189

Magnetic Flux Circulation During Dawn-Dusk Oriented Interplanetary Magnetic Field  

NASA Technical Reports Server (NTRS)

Magnetic flux circulation is a primary mode of energy transfer from the solar wind into the ionosphere and inner magnetosphere. For southward interplanetary magnetic field (IMF), magnetic flux circulation is described by the Dungey cycle (dayside merging, night side reconnection, and magnetospheric convection), and both the ionosphere and inner magnetosphere receive energy. For dawn-dusk oriented IMF, magnetic flux circulation is not well understood, and the inner magnetosphere does not receive energy. Several models have been suggested for possible reconnection patterns; the general pattern is: dayside merging; reconnection on the dayside or along the dawn/dusk regions; and, return flow on dayside only. These models are consistent with the lack of energy in the inner magnetosphere. We will present evidence that the Dungey cycle does not explain the energy transfer during dawn-dusk oriented IMF. We will also present evidence of how magnetic flux does circulate during dawn-dusk oriented IMF, specifically how the magnetic flux reconnects and circulates back.

Mitchell, E. J.; Lopez, R. E.; Fok, M.-C.; Deng, Y.; Wiltberger, M.; Lyon, J.

2010-01-01

190

Magnetic preferential orientation of metal oxide superconducting materials  

DOEpatents

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.

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

1990-07-17

191

2D magnetization of grain-oriented 3%-Si steel under uniaxial stress  

NASA Astrophysics Data System (ADS)

Magnetization in electrical steels is strongly affected by mechanical stress. The stress dependence of magnetic properties of non-oriented steels has been studied at one- and two-dimensional magnetization. This paper deals with the stress effect on one- and two-dimensional magnetization in grain-oriented 3%-Si steel. The special magnetic measurements system is applied to combine uniaxial stress and 2D magnetic measurements. The uniaxial stress ranges from 10 MPa compressive stress to 100 MPa tensile stress. A domain theory is a suitable tool for prediction and a physical explanation of stress dependency in grain-oriented steel.

Permiakov, V.; Dupré, L.; Pulnikov, A.; Melkebeek, J.

2005-04-01

192

Compass Needles around a Simple Circuit  

NSDL National Science Digital Library

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

2012-08-03

193

Magnetic properties of grain oriented electrical steel in model transformer under direct current-biased magnetization  

NASA Astrophysics Data System (ADS)

Iron losses and acoustic noises of the model transformer under DC-biased magnetization were empirically investigated. To clarify the influence of magnetic properties of transformer core materials, two types of grain oriented electrical steels—high permeability grade (HGO) and conventional grade (CGO)—were used as core materials. Iron losses increased with superimposing DC-bias magnetic field (HDC) in both materials, and the iron loss increment in HGO was larger than that in CGO. Acoustic noises increased with increasing HDC in both materials; however, noises emitted from the core of HGO were smaller than those of CGO.

Inoue, Hirotaka; Okabe, Seiji

2014-05-01

194

A double stage Kalman filter for sensor fusion and orientation tracking in 9D IMU  

Microsoft Academic Search

This work presents an orientation tracking system based on a double stage Kalman filter for sensor fusion in 9D IMU. The IMU is composed by a 3D gyro, a 3D accelerometer and a magnetic compass. The filter was divided into two stages to reduce algorithm complexity. Gyro data are used to first estimate the angular position, then the first stage

Simone Sabatelli; Marco Galgani; Luca Fanucci; Alessandro Rocchi

2012-01-01

195

Self-compassion and life satisfaction in gay men.  

PubMed

Studies have shown that gay men are at increased risk for anxiety and depression due to social oppression; research suggests that self-compassion is positively associated with life-satisfaction and emotional resilience. In a sample of 68 gay men (M age = 39.7 yr., SD = 16.3), the influence of self-compassion on satisfaction with life was examined while controlling for age, income, and openness about sexual orientation. Analysis of the data revealed that self-compassion was a significant predictor of satisfaction with life. Implications of this finding were discussed. PMID:25539176

Jennings, Lisa K; Philip Tan, P

2014-12-01

196

Commentary Magnetic maps in animals: nature's GPS  

Microsoft Academic Search

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,

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

197

Bats Use Magnetite to Detect the Earth's Magnetic Field  

PubMed Central

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 (Fe3O4). 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. PMID:18301753

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

2008-01-01

198

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

E-print Network

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

Ganichev, Sergey

2006-01-01

199

Solid containing rotationally free nanocrystalline gamma-Fe2O3: Material for a nanoscale magnetic compass?  

Microsoft Academic Search

A nanocomposite material has been characterized that contains nanometer size magnets that are free to rotate in response to an applied magnetic field. The composite consists of 5-10 nm crystals of gamma-Fe2O3 dispersed in a solid methanol polymer matrix. The material was prepared by freezing a methanol-based ferrofluid of gamma-Fe2O3 and subjecting it to a magnetic field applied in alternate

Javier Tejada; Xixiang Zhang; Elizabeth Kroll; Xavier Bohigas; Ronald F. Ziolo

2000-01-01

200

The role of daytime cues in the development of magnetic orientation in a night-migrating bird  

Microsoft Academic Search

To assess the role of celestial rotation during daytime in the development of the magnetic compass course, pied flycatchers\\u000a (Ficedula hypoleuca Pallas, Muscicapidae) were handraised in Latvia under various celestial and magnetic conditions. Tests were performed during\\u000a autumn migration in the local geomagnetic field (50?000 nT, 73° inclination) in the absence of celestial cues. A group of\\u000a birds that had

Peter Weindler; Frank Böhme; Varis Liepa; Wolfgang Wiltschko

1998-01-01

201

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

E-print Network

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

Phillips, John B.

202

Integration micro-magnetic sensor and accelerometer microsystem for orienting application  

Microsoft Academic Search

A scheme is presented for orienting application, which is based on micro-magnetic sensor and accelerometer, and the scheme can solve the orienting problems well. We have an optimized arrangement of the two sensors' positions, whi ch provides premise for establishing reference coordinate. An algorithm for completely oriented sensing is applied. In the algorithm, we take a concept of relative coordinate,

Weihua Li; Wenzhong Lou; Xin Li; Rongsen Hong; Liang Hu

2009-01-01

203

Magnetic Fields  

NSDL National Science Digital Library

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

2014-09-18

204

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

PubMed

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

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

2014-06-01

205

Large coercive field in magnetic-field oriented ?-Fe 2O 3 nanorods  

NASA Astrophysics Data System (ADS)

We report the fabrication and magnetic coercive field of oriented ?-Fe 2O 3 nanorods. Oriented ?-Fe 2O 3 nanorods embedded in SiO 2 matrix were obtained by a sol-gel method under an applied external magnetic field. The longitudinal axis, which corresponds to a-axis of the crystal structure of ?-Fe 2O 3 nanorods, was oriented parallel to the direction of external magnetic field. The sample achieved a magnetic coercive field along the longitudinal axis of 23.4 kOe, which is the largest value among metal oxide-based magnetic materials. The shape of the magnetic hysteresis loop is well understood by considering the magnetization rotation process and the uniaxial magnetic anisotropy.

Sakurai, Shunsuke; Shimoyama, Jun-ichi; Hashimoto, Kazuhito; Ohkoshi, Shin-ichi

2008-06-01

206

Prediction of structures and magnetic orientations in solid alpha and beta-O2  

NASA Technical Reports Server (NTRS)

A quasi-harmonic-lattice-dynamics method coupled with a pattern-recognition optimization scheme is used to determine the minimum energy structures and magnetic orientations of solid oxygen. It is shown that the magnetic interaction is responsible for the stability of alpha-O2 with respect to beta-O2 at zero temperature and pressure. The calculated alpha-O2 lattice parameters, magnetic orientations, and sublimation energy are in good agreement with experiment. Phonon dispersion curves are calculated at vector k not equal to zero and the acoustic sound velocities are determined. The rms translational and orientational fluctuations from equilibrium are also calculated. The beta-O2 phase is described by constraining the magnetic moments so that the magnetic Hamiltonian preserves the hexagonal symmetry of the crystal. The calculated lattice parameters are in good agreement with the experiments, and a three-sublattice, quasi-helical magnetic orientation is predicted from structural and energetic considerations.

Etters, R. D.; Helmy, A. A.; Kobashi, K.

1983-01-01

207

A method for absolute calibration of compasses  

NASA Astrophysics Data System (ADS)

In order to reference the speed and direction of ocean currents, currentmeters are fitted with a magnetic compass. The manufacturers of currentmeters provide users so-called autocalibration procedures and software to allow for the verification of the good working order and rectification of the bias of compass magnetic field sensors. Nevertheless, these tests do not make it possible to correct all the errors that can alter field measurements and particularly the nonlinear effects. In order to calculate corrections and estimate the accuracy of the 'autocalibration' procedure, an absolute calibration method has been devised, based on the GPS positioning of two geodetic reference points and on the measurement of angles and distances between one of these points and the instrument being tested. The standard uncertainty of this method has been assessed as 0.64°. It is below the compass accuracy and makes it possible to underscore the bias resulting from the 'autocalibration' operations and to evaluate corrections. This method, which can be extended to other equipment, is a solution for absolute compass calibrations.

LeMenn, Marc; LeGoff, Michel

2007-05-01

208

Smart Compass-Clinometer: A smartphone application for easy and rapid geological site investigation  

NASA Astrophysics Data System (ADS)

This study presents a smartphone application for geological site investigation. The application allows a smartphone to replace a diverse array of instrumentation and processes required for data measurement, visualization, and analysis. This application, named Smart Compass-Clinometer, consists of a digital compass-clinometer module, a data visualization module, a data analysis module, and a data management module. The compass-clinometer module measures the orientation of geological structures using data collected from built-in sensors. It converts the sensor data to orientation information using an algorithm developed specifically for this purpose. The visualization module plots the measured data on stereographic projections using three different methods, and can be used concurrently with the compass-clinometer module. The analysis module conducts instability analyses on the measured data, and can present the results in graphical and statistical forms. Users can send or receive data wirelessly with the data management module, even without a connection to a cellular network. To evaluate and validate the precision and accuracy of the compass-clinometer module, indoor and outdoor tests were conducted using Smart Compass-Clinometer and a conventional compass-clinometer. The minimum standard deviation of measured values with Smart Compass-Clinometer was 0.096° for dip and 0.122° for dip direction. The average difference between values measured using Smart Compass-Clinometer and the conventional compass-clinometer in the outdoor test was 1.70° for dip and 2.63° for dip direction. In an underground mine, the average discrepancies between Smart Compass-Clinometer and the conventional compass-clinometer were 2.57° in dip and 4.57° in dip direction. Smart Compass-Clinometer offers geoscientists a fast, reliable, and convenient tool for geological investigation.

Lee, Sangho; Suh, Jangwon; Park, Hyeong-dong

2013-12-01

209

Quantum correlation in one-dimensional extended quantum compass model  

NASA Astrophysics Data System (ADS)

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

You, W. L.

2012-02-01

210

Orientation of Nanowires Consisting of Poly(3-butylthiophene) Using Strong Magnetic Field  

NASA Astrophysics Data System (ADS)

Nanowires consisting of regioregular poly(3-butylthiophene) (P3BT) were prepared using o-dichlorobenzene. The magnetic processing of the nanowires was carried out using a superconducting magnet in the vertical (Bmax=10 T) direction. The formation of the nanowires was confirmed by atomic force microscopy (AFM). The polarized absorption spectra of the nanowires on a glass plate in the absence and presence of a magnetic field indicated that the nanowires partly oriented in the presence of magnetic fields (6 and 10 T). The magnetic orientation is most likely attributable to anisotropy in the magnetic susceptibility of the ordered P3BT in the nanowires. The AFM images of the nanowires on mica and the polarized absorption spectra of the nanowires on glass plates indicate that the nanowires partly oriented themselves with their long axes, which are perpendicular to the ?-? stacking direction, parallel to the magnetic field.

Yonemura, Hiroaki; Yuno, Koichi; Yamada, Sunao

2010-01-01

211

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

NASA Astrophysics Data System (ADS)

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.

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

2014-01-01

212

Analysis and optimization of vertically oriented, through-wafer, laminated magnetic cores in silicon  

Microsoft Academic Search

This paper compares two fabrication methods for achieving through-wafer, laminated magnetic cores in silicon, intended for microfabricated magnetic devices where vertically oriented (normal to the wafer) magnetic laminations are required to reduce eddy current losses. Given certain fabrication constraints for each method, a theoretical framework is presented to permit the design of the optimal lamination scheme for a particular application.

David P Arnold; Iulica Zana; Mark G Allen

2005-01-01

213

The control of crystal orientation in ceramics by imposition of a high magnetic field  

Microsoft Academic Search

From the viewpoint of high magnetic field effect, researches on which the crystal orientation of feeble magnetic ceramics was controlled by using a slip casting under a high magnetic field have been carefully reviewed. Both of the reported results and the experimental results obtained by the present authors indicate that gravity force also plays an important role for crystal alignment

Shuqin Li; Cunyou Wu; Kensuke Sassa; Shigeo Asai

2006-01-01

214

Resource representation in COMPASS  

NASA Technical Reports Server (NTRS)

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

Fox, Barry R.

1991-01-01

215

Charter for Compassion  

NSDL National Science Digital Library

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

216

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

Federal Register 2010, 2011, 2012, 2013, 2014

...30550; 812-13881] Compass Efficient Model Portfolios, LLC and Compass EMP Funds...approval. Applicants: Compass Efficient Model Portfolios, LLC (the ``Adviser...Enhanced Fixed Income Fund, Compass EMP Ultra Short-Term Fixed Income Fund,...

2013-06-11

217

Compass magnetoreception in birds arising from photo-induced radical pairs in rotationally disordered cryptochromes.  

PubMed

According to the radical pair model, the magnetic compass sense of migratory birds relies on photochemical transformations in the eye to detect the direction of the geomagnetic field. Magnetically sensitive radical pairs are thought to be generated in cryptochrome proteins contained in magnetoreceptor cells in the retina. A prerequisite of the current model is for some degree of rotational ordering of both the cryptochromes within the cells and of the cells within the retina so that the directional responses of individual molecules do not average to zero. Here, it is argued that anisotropic distributions of radical pairs can be generated by the photoselection effects that arise from the directionality of the light entering the eye. Light-induced rotational order among the transient radical pairs rather than intrinsic ordering of their molecular precursors is seen as the fundamental condition for a magnetoreceptor cell to exhibit an anisotropic response. A theoretical analysis shows that a viable compass magnetoreceptor could result from randomly oriented cryptochromes contained in randomly oriented cells distributed around the retina. PMID:22977104

Lau, Jason C S; Rodgers, Christopher T; Hore, P J

2012-12-01

218

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

PubMed Central

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

Holland, Richard A.

2010-01-01

219

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

PubMed

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. PMID:25420004

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

2014-12-16

220

Visual compass Frederic Labrosse  

E-print Network

the precise localisation of the robot. The Global Positioning System (GPS) is such a system. Sometimes and sometimes constraining. For example, GPS needs a set of satellites orbiting above the robot in direct view accelerometers. These sensors all suffer from limitations. For example, a compass needs a well known

Labrosse, Frédéric

221

Bow Compass with Case  

USGS Multimedia Gallery

Bow Compass with Case. Also known as a Drop Bow Pen or Spring Bow, serial #760 C. This instrument was made by Eugene Dietzgen & Company, Chicago and New York and used by the U.S. Geological Survey Topographic Branch after 1945-1960s. Object ID: USGS-000645...

222

The British Museum COMPASS  

NSDL National Science Digital Library

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

223

Design of Magnetic Orientation System Based on GMR Sensor and MCU  

Microsoft Academic Search

A newly developed high accuracy, low cost magnetic orientation system is introduced in this paper. The constitution of the orientation system is presented. We get the data of geomagnetic field by the GMR sensor. Because of the complex noise mixing in the signal, we need to decrease the noise so that we can pick up purer geomagnetic signal and realize

Lu Zhicai; Mi Dong; Xu Zhangsui; Yao Zhimin; Zhang Weixin

2010-01-01

224

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

PubMed Central

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

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

2014-01-01

225

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

PubMed

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

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

2014-09-01

226

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

Microsoft Academic Search

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

Lukas Landler; Günter Gollmann

2011-01-01

227

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

PubMed Central

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

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

2014-01-01

228

Statistical study of low-frequency magnetic field fluctuations near Venus under the different interplanetary magnetic field orientations  

Microsoft Academic Search

The magnetic field fluctuations near Venus are investigated in the frequency range 0.03–0.3 Hz on the basis of the measurements observed by Venus Express from April 2006 to December 2008. The data are sorted by the angle between interplanetary magnetic field (IMF) and solar wind flow. The spatial distributions of fluctuation properties under the different IMF orientations are presented and

J. Du; T. L. Zhang; W. Baumjohann; C. Wang; M. Volwerk; Z. Vörös; L. Guicking

2010-01-01

229

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

PubMed

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

Wiltschko, Roswitha; Wiltschko, Wolfgang

2014-09-01

230

Sensing Magnetic Directions in Birds: Radical Pair Processes Involving Cryptochrome  

PubMed Central

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

Wiltschko, Roswitha; Wiltschko, Wolfgang

2014-01-01

231

The Role of Self-compassion in Women's Self-determined Motives to Exercise and Exercise-related Outcomes  

Microsoft Academic Search

Self-compassion is emerging in the literature as a healthy conceptualization of the self (Neff, 2003a). This study explored how self-compassion is related to, and explains unique variance beyond self-esteem on, women's motives to exercise and exercise-related outcomes. Participants were 252 women exercisers. Self-compassion was positively related to intrinsic motivation and negatively related to external and introjected motivation, ego goal orientation,

Cathy M. R. Magnus; Kent C. Kowalski; Tara-Leigh F. McHugh

2010-01-01

232

Manipulations of polarized skylight calibrate magnetic orientation in a migratory bird  

Microsoft Academic Search

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

K. P. Able; M. A. Able

1995-01-01

233

Effect of Elastic Bending on Magnetic Properties of Oriented Silicon Iron  

Microsoft Academic Search

To determine how the a-c and d-c magnetic properties are affected by ; elastic strain, the magnetic properties in the rolling direction of Epstein ; strips of elastically bent grain-oriented 3% silicon iron were measured in an ; Epstein frame and in a Carr single-strip permeameter. As the degree of bending ; becomes more pronounced the coercive force and the

R. W. Cole

1958-01-01

234

Prediction of particle orientation in simple upsetting process of NdFeB magnets  

SciTech Connect

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.

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

2013-12-16

235

Interaction of body condition and magnetic orientation in autumn migrating robins, Erithacus rubecula  

Microsoft Academic Search

Earlier experimental studies have demonstrated that autumn migrating robins, passing a stop- over site in southeastern Sweden, use the geomagnetic field for orientation. However, when exposed to experimentally deflected magnetic fields about half of the test birds preferred magnetic directions that were reverse (northeasterly) from normal (southwesterly), thus resulting in axial (bimodal) distributions. The resulls were difficult to interpret in

ROLAND SANDBERG

1994-01-01

236

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

SciTech Connect

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.

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

2008-08-18

237

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

PubMed Central

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

2011-01-01

238

The COMPASS Project  

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

239

Pico Cricket Compass  

NSDL National Science Digital Library

Learners can program a compass to draw a circle by itself using a Pico Cricket, some Legos, and lots of tape! Pico Cricket is required. This activity teaches learners how to program a micro controller (mini computer), how to use gears and motors, and includes a video of the final product in action. This activity could made into a one-hour workshop if more programing was involved to draw a half circle or a quarter of a circle.

Science Museum of Minnesota

2014-06-30

240

Magnet Mania  

NSDL National Science Digital Library

In this activity, learners explore the relationship between electric charges and magnetic fields. Learners create a magnetic field using electricity and observe its effect on the magnetic needle of a compass.

2012-06-26

241

Crystal orientation in Bi-based superconducting glass-ceramics prepared in high magnetic field  

Microsoft Academic Search

A high magnetic field of 10T was applied to the crystallization process of Bi2Sr2CaCu2Ox superconducting precursor glasses, and the effect of high magnetic field on crystal grain orientations and superconducting properties were examined from electrical resistivity measurements, X-ray diffraction analyses and scanning electron microscope observations. The glass-ceramics prepared in a high magnetic field show better superconducting properties (higher critical temperature,

N. Toyohara; Y. Benino; T. Fujiwara; S. Tanaka; K. Uematsu; T. Komatsu

2005-01-01

242

Drawing Magnetic Fields  

NSDL National Science Digital Library

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

2014-09-18

243

Magnetic properties of hexagonal oxide ferrimagnets with orientational transitions  

Microsoft Academic Search

We study the magnetic structure of different types of hexaferrites, BaCoxTixFe12-2xO19(M), BaCo2-xZnxFe16O27(W), and Ba3Co2.4Ti0.4Fe23.2O41 (Z), and determine the concentration and temperature regions whre magnetically ordered phases such as the cone, plane, and axis of easy magnetization phases exist and the order of the magnetoorientational phase transitions. The constants of magnetic crystal anisotropy, including those of a higher order, were determined

S. M. Zhilyakov; E. P. Naiden; G. I. Ryabtsev

1992-01-01

244

MAGNETIZED FIBER ORIENTATION AND CONCENTRATION CONTROL IN SOLIDIFYING COMPOSITES  

Microsoft Academic Search

A new concept for manufacturing specialty composite materials has been developed where a user-specified pattern of magnetic lines of force can be achieved so that micro fibers will align with this pattern. An improved analytical model and a numerical algorithm have been developed for the prediction of magnetic force lines inside a flowing and solidifying melt. This analysis code was

George S. Dulikravich; Marcelo J. Colaço; Thomas J. Martin; Seungsoo Lee

2003-01-01

245

Daytime TV's day of compassion for AIDS.  

PubMed

Daytime television's national Day of Compassion programming, a Hollywood Supports-sponsored event where entire shows and storylines were devoted to HIV/AIDS topics, is highlighted. Programming successes are examined, including cable TV's contribution to the event and the general public's approval. Richard Jennings of Hollywood Supports, the entertainment industry group that works to counter workplace fears and discrimination based on HIV status and sexual orientation, states that he and his group are aiming at prime time next year. This mission is particularly important now given the tenor of hateful distortion about people with AIDS from the religious right and the current mood of Congress towards AIDS-related funding. PMID:11362727

McFarlane, R

1995-07-01

246

Modeling of Magnetic Domain in Grain-Oriented Electrical Steel Sheets based on Multi-directional Magnetostriction Measurements  

NASA Astrophysics Data System (ADS)

In this paper, a novel magnetic domain model on grain-oriented electrical steel was established which is based on magnetostriction measurements for an interpretation of the magnetization behavior under rotational magnetization process. The novel model has brought about useful insights for understanding on reconstruction of magnetic domain and kinetics of magnetic domain wall.

Yamaguchi, Hiroi; Pfützner, Helmut; Honda, Atsuhito

247

Exploring Magnetic Field Lines  

NSDL National Science Digital Library

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

2012-06-26

248

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

PubMed Central

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

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

2014-01-01

249

Effect of crystallographic texture on the bulk magnetic properties of non-oriented electrical steels  

NASA Astrophysics Data System (ADS)

Quantitative physical models for non-oriented electrical steels require precise knowledge of chemical and microstructural parameters for the material, with crystallographic texture being one of the most important. Describing the structure-property relationships in these materials is made difficult in that all of the parameters have an effect on magnetic properties. In the present study, a set of non-oriented electrical steel specimens are examined, where chemistry and grain size are kept similar from sample to sample, but texture is varied. A new texture parameter called Magnetic Texture Factor is introduced which is defined as the ratio of the volume fractions of <100> direction to <111> direction along magnetization vector. It was found that this Magnetic Texture Factor was a better parameter for identifying trends of magnetic properties with crystallographic texture than the often used Texture Factor, which is described as the ratio of the volume fractions of {100} planes to {111} planes.

Ghosh, Pampa; Chromik, Richard R.; Vaseghi, Babak; Knight, Andrew M.

2014-09-01

250

The geographical scale factor in orientation of migrating birds  

PubMed

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. PMID:9317235

Alerstam

1996-01-01

251

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

PubMed

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. PMID:25390070

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

2014-12-01

252

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

PubMed Central

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

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

2005-01-01

253

Cultivating Compassion: Rhetoric or Reality?  

ERIC Educational Resources Information Center

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…

Lovette-Colyer, Michael

2014-01-01

254

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

PubMed Central

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

Sabatini, Angelo Maria

2011-01-01

255

Quantitative vertebral compression fracture evaluation using a height compass  

NASA Astrophysics Data System (ADS)

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.

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

2012-03-01

256

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

ERIC Educational Resources Information Center

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…

Hancharik, Sharon D.

2008-01-01

257

Biomimetic Attitude and Orientation Sensors  

Microsoft Academic Search

We developed and flight-tested two biomimetic sensors that use the spectral, spatial and polarization distribution of light in the environment for navigation and stabilization. A sky polarization compass was constructed and methodologies for precise calibration were developed. In static and flight testing, the calibrated device was found to be comparable in accuracy to a solid state magnetic compass. A biomimetic

Javaan Chahl; Akiko Mizutani

2012-01-01

258

Orientation and open-sea navigation in sea turtles  

PubMed

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. PMID:9317364

Lohmann; Lohmann

1996-01-01

259

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

Microsoft Academic Search

After making foraging flights of several thousands of kilometres, wandering albatrosses (Diomedea exulans) are able to pinpoint a specific remote island where their nests are located. This impressive navigation ability is highly precise but its nature is mysterious. Here we examined whether albatrosses rely on the perception of the Earth's magnetic field to accomplish this task. We disturbed the perception

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

2005-01-01

260

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

261

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

262

Relationship between coercive force and anisotropy field for oriented barium ferrite tapes and magnets  

Microsoft Academic Search

The approximate anisotropy field (Han) has been determined for twelve experimental oriented barium ferrite recording tapes and magnets with coercive force (Hc) between 715 Oe and 5250 Oe, and squareness ratio greater than 0.80. The Han values were taken as the ratio of saturation magnetic moment (ms) to the initial hard-axis susceptibility (m\\/H). Han values were generally within the 12.6–19.8

R. E. Fayling

1978-01-01

263

Relationship between coercive force and anisotropy field for oriented barium ferrite tapes and magnets  

Microsoft Academic Search

The approximate anisotropy field (Han) has been determined for twelve experimental oriented barium ferrite recording tapes and magnets with coercive force (Hc) between 715 Oe and 5250 Oe, and squareness ratio greater than 0.80. The Han values were taken as the ratio of saturation magnetic moment (ms) to the initial hard-axis susceptibility (m\\/H). Han values were generally within the 12.6-19.8

R. E. Fayling

1978-01-01

264

Ac magnetorestriction hysteresis and magnetization direction in grain oriented silicon steels  

SciTech Connect

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.

Mogi, Hisashi; Matsuo, Yukio; Kumano, Tomoji

1999-09-01

265

Orientation of migratory birds under ultraviolet light.  

PubMed

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

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

2014-05-01

266

GPS Occultation Observations of Equatorial Scintillation: Dependence on Magnetic Field Orientation, Longitude, and Season  

NASA Astrophysics Data System (ADS)

We analyzed GPS occultation data from the CHAMP, SAC-C, and PICOSat satellite for the entire year 2002 identifying radiowave scintillation occurrence from SNR measurements of the C/A code on the L1 frequency obtained at the 1-second rate cadence. Global distributions clearly indicate that we are observing equatorial scintillation and scintillation in the auroral zones and polar cap. Seasonal and magnetic local time distributions of the low-latitude observations are in good agreement with the known distributions of equatorial scintillation. Longitudinal distributions vary somewhat from the WBMOD climatological model, particularly in the African sector where scintillation is observed nearly all year. A strong dependence on the orientation of the occultation ray path with the magnetic field orientation is observed with a low probability of scintillation at ray path angles perpendicular to the magnetic field and high probability of observations at smaller angles. This is interpreted as the result of the orientation of the ionospheric bubbles responsible for the scintillation. The walls of the bubbles, on which the instabilities that cause the scintillation occur, are typically aligned with the magnetic field. Thus, occultation ray paths along the magnetic field pass along the edge of the bubbles and remain within the region of instabilities for a longer period that ray paths perpendicular to the magnetic field and the bubble walls.

Anderson, P. C.; Straus, P. R.

2004-12-01

267

Friction and scratch resistance of polymer liquid crystals: Effects of magnetic field orientation  

E-print Network

Friction and scratch resistance of polymer liquid crystals: Effects of magnetic field orientation fraction of 0.6 PHB. It is a longitudinal polymer liquid crystal (PLC) with the LC sequences in the main the scratch resistance of the same commercial epoxy.9 This time, we work on polymer liquid crystals (PLCs

North Texas, University of

268

Effects of Flow Induced Orientation of Ferromagnetic Particles on Relative Magnetic Permeability of  

E-print Network

particles are mixed with polymeric binders, solvents, plasticizers, lubricants and other additives to form a paint. The paint is applied to a polymer substrate (coated) and the particles are oriented by applying application of the ferromagnetic compos- ites is in plastic magnets. Since their introduction (7) they have

269

Local magnetic properties in grain-oriented electrical steel measured by the modified needle probe method  

NASA Astrophysics Data System (ADS)

Distribution of local magnetic properties in grain-oriented electrical steel was investigated using the needle probe method. The spatial nonuniformity of flux density was found to be affected by magentic poles on grain boundaries which mainly depend on the ? angles between neighbouring grains and on the direction of grain boundaries.

Senda, K.; Kurosawa, M.; Ishida, M.; Komatsubara, M.; Yamaguchi, T.

2000-06-01

270

The Structure of a Lyotropic Liquid Crystalline Phase that Orients in a Magnetic Field  

Microsoft Academic Search

The structure of a lyotropic liquid crystalline phase with positive diamagnetic anisotropy (type I), that spontaneously orients in a magnetic field has been studied by means of water NMR quadrupole splittings, NMR diffusion and polarized absorption spectroscopy. It is concluded that this phase is built up of long rodlike aggregates. A preliminary study of a sample with negative diamagnetic anisotropy

Olle Söderman; Göran Lindblom; Lennart B.-Å. Johansson; Krister Fontell

1980-01-01

271

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...

272

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

Microsoft Academic Search

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

H. Bouquerel; J. P. Valet

2003-01-01

273

Orientation Dependence of the Critical Magnetic Field for Multiferroic BiFeO3  

SciTech Connect

Multiferroic BiFeO3 undergoes a transition from a distorted spiral phase to a G-type antiferromagnet above a critical field Hc that depends on the orientation m of the field. We show that Hc(m) has a maximum when oriented along a cubic diagonal parallel to the electric polarization P and a minimum in the equatorial plane normal to P when two magnetic domains with the highest critical fields are degenerate. The measured critical field along a cubic axis is about 19 T but Hc is predicted to vary by as much as 2.5 T above and below this value. The orientational dependence of Hc(m) is more complex than indicated by earlier work, which did not consider the competition between magnetic domains.

Fishman, Randy Scott [ORNL

2013-01-01

274

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

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

275

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

Microsoft Academic Search

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

Y. Hoshi; M. Naoe

1987-01-01

276

Virtual migration in tethered flying monarch butterflies reveals their orientation mechanisms  

PubMed Central

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

Mouritsen, Henrik; Frost, Barrie J.

2002-01-01

277

Magnetic properties of thin gauge 3% Si-Fe with {110}<001> orientation  

NASA Astrophysics Data System (ADS)

Thin-gauge 3% Si-Fe with {110}<001> orientation is a suitable material for magnetic devices in the frequency range from 102 to 105 Hz. Low core loss and high permeability in this frequency range are required. With recently developed, highly grain-oriented materials, physical parameters that affect core losses were investigated as a function of excitation frequency and magnetic flux density. The relationship between core loss and excitation conditions is classified into four regions. This material is useful for transformers and inductors, especially for higher flux density application in the middle frequency region (Bm[maximum excitation magnetic flux density] > 1T, 102 to 103 Hz), such as airplane devices.

Ushigami, Y.; Okazaki, Y.; Abe, N.; Kumano, T.; Kikuchi, M.; Inokuchi, T.

1995-08-01

278

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

E-print Network

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

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

2014-10-28

279

Hadron spectroscopy with COMPASS  

NASA Astrophysics Data System (ADS)

COMPASS is a multi-purpose fixed-target experiment at the CERN Super Proton Synchrotron aimed at studying the structure and spectrum of hadrons. One primary goal is the search for new hadronic states, in particular spin-exotic mesons and glueballs. We present recent results of partial-wave analyses of (3?)- and ?- ?' final states based on a large data set of diffractive dissociation of a 190 GeV/c ?- beam on a proton target in the squared four-momentum-transfer range 0.1

Grube, Boris; Compass Collaboration

2012-09-01

280

Sensitive chemical compass assisted by quantum criticality  

NASA Astrophysics Data System (ADS)

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.

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

2012-02-01

281

Orienteering and Rogaining Server  

NSDL National Science Digital Library

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

282

Statistical Assessment of Shapes and Magnetic Field Orientations in Molecular Clouds through Polarization Observations  

NASA Astrophysics Data System (ADS)

We present a novel statistical analysis aimed at deriving the intrinsic shapes and magnetic field orientations of molecular clouds using dust emission and polarization observations by the Hertz polarimeter. Our observables are the aspect ratio of the projected plane-of-the-sky cloud image, and the angle between the mean direction of the plane-of-the-sky component of the magnetic field and the short axis of the cloud image. To overcome projection effects due to the unknown orientation of the line-of-sight, we combine observations from 24 clouds, assuming that line-of-sight orientations are random and all are equally probable. Through a weighted least-squares analysis, we find that the best-fit intrinsic cloud shape describing our sample is an oblate disk with only small degrees of triaxiality. The best-fit intrinsic magnetic field orientation is close to the direction of the shortest cloud axis, with small (~24 deg) deviations toward the long/middle cloud axes. However, due to the small number of observed clouds, the power of our analysis to reject alternative configurations is limited.

Tassis, K.; Dowell, C. D.; Hildebrand, R. H.; Kirby, L.; Vaillancourt, J. E.

2009-11-01

283

Sunset and the orientation of a nocturnal migrant bird  

Microsoft Academic Search

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

Frank R. Moore

1978-01-01

284

The link between magnetic fields and filamentary clouds: bimodal cloud orientations in the Gould Belt  

NASA Astrophysics Data System (ADS)

The orientations of filamentary molecular clouds in the Gould Belt and their local intercloud media (ICM) magnetic fields are studied using near-infrared dust extinction maps and optical stellar polarimetry data. These filamentary clouds are a few-to-10 pc in length, and we find that their orientations tend to be either parallel or perpendicular to the mean field directions of the local ICM. This bimodal distribution is not found in cloud simulations with super-Alfvénic turbulence, in which the cloud orientations should be random. ICM magnetic fields that are dynamically important compared to inertial range turbulence and self-gravity can readily explain both field-filament configurations. Previous studies commonly recognize that strong magnetic fields can guide gravitational contraction and result in filaments perpendicular to them, but few discuss the fact that magnetic fields can also channel sub-Alfvénic turbulence to form filaments aligned with them. This strong-field scenario of cloud formation is also consistent with the constant field strength observed from ICM to clouds and is possible to explain the `hub-filament' cloud structure and the density threshold of cloud gravitational contraction.

Li, Hua-bai; Fang, Min; Henning, Thomas; Kainulainen, Jouni

2013-12-01

285

Compassion and professional care: exploring the domain.  

PubMed

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. PMID:19291200

van der Cingel, Margreet

2009-04-01

286

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

PubMed Central

An imaging method for the rapid reconstruction of fiber orientation throughout the cardiac ventricles is described. In this method, gradient-recalled acquisition in the steady-state (GRASS) imaging is used to measure ventricular geometry in formaldehyde-fixed hearts at high spatial resolution. Diffusion-tensor magnetic resonance imaging (DTMRI) is then used to estimate fiber orientation as the principle eigenvector of the diffusion tensor measured at each image voxel in these same hearts. DTMRI-based estimates of fiber orientation in formaldehyde-fixed tissue are shown to agree closely with those measured using histological techniques, and evidence is presented suggesting that diffusion tensor tertiary eigenvectors may specify the orientation of ventricular laminar sheets. Using a semiautomated software tool called heartworks, a set of smooth contours approximating the epicardial and endocardial boundaries in each GRASS short-axis section are estimated. These contours are then interconnected to form a volumetric model of the cardiac ventricles. DTMRI-based estimates of fiber orientation are interpolated into these volumetric models, yielding reconstructions of cardiac ventricular fiber orientation based on at least an order of magnitude more sampling points than can be obtained using manual reconstruction methods. PMID:11144678

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

2005-01-01

287

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

NASA Astrophysics Data System (ADS)

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).

Kirschvink, Joe

2011-03-01

288

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

Microsoft Academic Search

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

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

1997-01-01

289

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

Microsoft Academic Search

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

C. D. Craig; G. Sprang

2010-01-01

290

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

E-print Network

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

Adeyeye, Adekunle

291

Magnetic Properties and Domain Structure of Non-oriented Electrical Steel Under Stress  

NASA Astrophysics Data System (ADS)

The influence of stresses on the magnetic properties of non-oriented electrical steels was studied. The dependence of iron loss on compressive stress was affected by grain size. The magnetic polarization J at high magnetic fields such as 5000A/m and 10000A/m increased by compressive stresses and decreased by tensile stresses in samples with low Si contents. Using Kerr-effect domain observation, it was found that the reduction in J caused by tensile stresses was attributable to residual striped domains. Magnetostriction measurements at high magnetic fields indicated that the increase in J under compressive stresses originated from the Villari-effect due to negative magnetostriction in low Si materials.

Senda, Kunihiro; Fujita, Akira; Honda, Atsuhito; Kuroki, Naoki; Yagi, Masaaki

292

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

PubMed Central

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

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

2014-01-01

293

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

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

294

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

NASA Astrophysics Data System (ADS)

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

Bracco, Andrea; Planck Collaboration

2015-01-01

295

Flux controlled magnetic barkhausen noise measurements on grain oriented electrical steels  

NASA Astrophysics Data System (ADS)

This paper investigates magnetic Barkhausen noise (MBN) in grain-oriented electrical steel using flux-control and its relationship to power losses obtained from standard Epstein tests. The effects of flux, frequency, grain size and texture in five samples of similar thickness with known core loss values were examined. A comparison with a non-oriented sample indicated that the grain oriented Si-Fe has higher magnetic anisotropy and greater MBN signal variability with position, which is associated with its larger grain size. Angular MBN measurements demonstrated a major easy axis along the rolling direction (RD) that was attributed to its Goss texture. An inverse relation between MBN energy and core loss values was observed. The inverse relation was associated with a greater proportion of Barkhausen events with magnetization changes projected out of the plane of the sample. This generates microscopic eddy currents that do not add vectorily to the bulk eddy currents and thereby reduces excess power losses. Post publication note (25 July 2012): Author affiliations were corrected.

Samimi, Arash A.; Krause, Thomas W.; Clapham, Lynann

2012-07-01

296

Delta G from Compass  

E-print Network

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

Krzysztof Kurek

2006-07-26

297

Gluon Polarisation Measurements @ COMPASS  

E-print Network

One of the missing keys in the present understanding of the spin structure of the nucleon is the contribution from the gluons: the so-called gluon polarisation. This quantity can be determined in DIS through the photon-gluon fusion process, in which two analysis methods may be used: (i) identifying open charm events or (ii) selecting events with high p_T hadrons. The data used in the present work were collected in the COMPASS experiment, where a 160 GeV/c naturally polarised muon beam, impinging on a polarised nucleon fixed target is used. Preliminary results for the gluon polarisation from high p_T and open charm analyses are presented. The gluon polarisation result for high p_T hadrons is divided, for the first time, into three statistically independent measurements at LO. The result from open charm analysis is obtained at LO and NLO. In both analyses a new weighted method based on a neural network approach is used.

Luís Silva; for the COMPASS Collaboration

2011-11-02

298

Self-Compassion and Automatic Thoughts  

ERIC Educational Resources Information Center

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…

Akin, Ahmet

2012-01-01

299

Self-Compassion and Interpersonal Cognitive Distortions  

ERIC Educational Resources Information Center

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…

Akin, Ahmet

2010-01-01

300

Rousseau and the Education of Compassion  

ERIC Educational Resources Information Center

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…

White, Richard

2008-01-01

301

Regulation of the Neural Circuitry of Emotion by Compassion Meditation: Effects of Meditative Expertise  

Microsoft Academic Search

Recent brain imaging studies using functional magnetic resonance imaging (fMRI) have implicated insula and anterior cingulate cortices in the empathic response to another's pain. However, virtually nothing is known about the impact of the voluntary generation of compassion on this network. To investigate these questions we assessed brain activity using fMRI while novice and expert meditation practitioners generated a loving-kindness-compassion

Antoine Lutz; Julie Brefczynski-Lewis; Tom Johnstone; Richard J. Davidson

2008-01-01

302

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

NASA Technical Reports Server (NTRS)

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

Martin, James J.; Holt, James B.

2000-01-01

303

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

304

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

NASA Astrophysics Data System (ADS)

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.

Bouquerel, H.; Valet, J. P.

2003-04-01

305

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

306

Molecular chain orientation of DNA films induced by both the magnetic field and the interfacial effect.  

PubMed

DNA films showing highly homogeneous orientation of molecular chains were successfully prepared by drying a semidiluted solution in a horizontal magnetic field. Most of the molecular chain elements in the obtained film were found to be one-dimensionally oriented, as shown by X-ray diffraction, polarization microscopy, and linear dichroism spectroscopy. Because a DNA chain is theoretically expected to orientate only in divergent directions perpendicular to a magnetic field, this result suggests that the DNA chains were aligned not only by a magnetic field but also by the interfacial effect that induced the chains to fit along the air-liquid interface. The descent speed of an air-liquid interface by evaporation was faster than the estimated diffusion rate of DNA, suggesting an emergence of a concentrated layer near the surface. As proved by polarization microscopy, this emergence led to the transitional formation of a nematic-like liquid crystalline phase, which resulted in a DNA film with good chain alignment and unitary orientation. This mechanism underlying chain alignment was supported by molecular weight dependency, in which higher molecular weight DNA is more likely to evince chain alignment that exhibits a higher degree of birefringence. Low molecular weight components have such high thermal motility that it would be difficult to fit them along the air-liquid interface in the early stage of drying. For chain alignment, it was preferable to use an initial concentration of DNA lower than a critical concentration for liquid crystal formation so that the possible diffusion and assembly in a diluted solution would be essential for chain alignment. The DNA film exhibited obvious linear dichroism, indicating the potential for further applications. PMID:15530045

Morii, Nahoko; Kido, Giyuu; Suzuki, Hiroyuki; Nimori, Shigeki; Morii, Hisayuki

2004-01-01

307

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

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

308

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

SciTech Connect

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

Cohen, R H; Yang, T Y Brian

1999-03-04

309

Magnetic orientation and magnetically sensitive material in a transequatorial migratory bird  

Microsoft Academic Search

A variety of animal species is sensitive to changes in natural and artificial magnetic fields. The receptor mechanism for this ability has been described for a few species, most notably magnetotactic bacteria1 and potential receptors have been reported for such animals as honey bees, homing pigeons and dolphins2-5. Some species of migratory birds also perceive changes in magnetic field6. We

Robert C. Beason; Joan E. Nichols

1984-01-01

310

RESEARCH PAPER Enhancing Compassion: A Randomized Controlled Trial  

E-print Network

--compassion for others, receiving compassion from others, and self-compassion. The amount of formal meditation practiced and well-being. Keywords Compassion Á Self-compassion Á Meditation Á Training 1 Introduction Most University, Stanford, CA, USA 123 J Happiness Stud (2013) 14:1113­1126 DOI 10.1007/s10902-012-9373-z #12;and

Gross, James J.

311

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

PubMed

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

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

2014-01-01

312

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

PubMed Central

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

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

2014-01-01

313

The COMPASS experiment at CERN  

Microsoft Academic Search

The COMPASS experiment makes use of the CERN SPS high-intensity muon and hadron beams for the investigation of the nucleon spin structure and the spectroscopy of hadrons. One or more outgoing particles are detected in coincidence with the incoming muon or hadron. A large polarised target inside a superconducting solenoid is used for the measurements with the muon beam. Outgoing

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

2007-01-01

314

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

PubMed

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

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

2011-08-01

315

Delta-opiate DPDPE in magnetically oriented phospholipid micelles: binding and arrangement of aromatic pharmacophores.  

PubMed Central

D-Penicillamine(2,5)-enkephalin (DPDPE) is a potent opioid peptide that exhibits a high selectivity for the delta-opiate receptors. This zwitterionic peptide has been shown, by pulsed-field gradient 1H NMR diffusion studies, to have significant affinity for a zwitterionic phospholipid bilayer. The bilayer lipid is in the form of micelles composed of dihexanoylphosphatidylcholine (DHPC) and dimyristoylphosphatidylcholine (DMPC) mixtures, where the DMPC forms the bilayer structure. At high lipid concentration (25% w/w) these micelles orient in the magnetic field of an NMR spectrometer. The resulting 1H-13C dipolar couplings and chemical shift changes in the natural abundance 13C resonances for the Tyr and Phe aromatic rings were used to characterize the orientations in the bilayer micelles of these two key pharmacophores. Images FIGURE 1 FIGURE 8 PMID:9414244

Rinaldi, F; Lin, M; Shapiro, M J; Petersheim, M

1997-01-01

316

Possible influence of sulfur content on magnetic aging behaviors of non-oriented electrical steels  

NASA Astrophysics Data System (ADS)

Six non-oriented steel sheets of similar grade produced by different steel companies were used to analyze the magnetic aging behaviors after aging at 200°C for 48 h. It was observed that tiny S atoms, besides C and N, could also induce certain increase of core loss during aging. Thermodynamic calculation indicated that the nucleation driving force of FeS is much higher than those of Fe3C and Fe4N at low temperature, while S atoms, which tend to segregated around dislocations and boundaries, would diffuse rapidly along the crystalline defects while FeS particles would form. Therefore, higher content of tiny S atoms could increase core loss during service time of non-oriented steel sheets.

Mao, Wei-Min; Yang, Ping; Li, Chang-Rong

2013-12-01

317

Oriented inclusions of magnetite in clinopyroxene: Source of stable remanent magnetization in gabbros of the Messum Complex, Namibia  

Microsoft Academic Search

Crystallographically oriented and highly elongate magnetite inclusions in clinopyroxene are the dominant source of highly stable remanent magnetization in gabbros of the Early Cretaceous Messum Complex, Namibia. Rock magnetic properties determined for individual pyroxene crystals indicate a high proportion of single-domain magnetite, consistent with the observed sizes and shape anisotropy of the magnetite inclusions. As in previous studies of similar

Paul R. Renne; Gary R. Scott; Jonathan M. G. Glen; Joshua M. Feinberg

2002-01-01

318

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

E-print Network

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

Seifried, D

2015-01-01

319

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

PubMed Central

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

Sabatini, Angelo Maria

2012-01-01

320

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

NASA Astrophysics Data System (ADS)

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.

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

2006-09-01

321

EFFICIENCY ENHANCEMENTS THROUGH THE USE OF MAGNETIC FIELD GRADIENT IN ORIENTATION MAGNETIC SEPARATION FOR THE REMOVAL OF POLLUTANTS BY MAGNETOTACTIC BACTERIA  

Microsoft Academic Search

Orientation magnetic separation (OMS) represents a simple method that permits motile, field-susceptible magnetotactic bacteria (MTB) to be separated from water. Such an approach can be used to decontaminate polluted water through uptake of contaminants by the bacteria and their subsequent removal by the application of magnetic fields. In OMS, a separation channel through which an MTB culture is flowing is

A. S. Bahaj; P. A. B. James; F. D. Moeschler

2002-01-01

322

Relationship between magnetic domain configuration and crystallographic orientation in a colossal magnetoresistive material.  

PubMed

We investigated the relationship between the magnetic domain (MD) configuration and crystallographic orientation in a colossal magnetoresistive (CMR) material La(0.69)Ca(0.31)MnO(3) in which anisotropic magnetoresistance (AMR) was observed as well. It was observed that the MD structure with a micrometre scale in the (001) plane collapses when a modulated structure with a nanometre scale emerges near the Curie temperature (T(c)). On the other hand, twin boundaries were observed to develop in the (110) plate, and they pin the MD walls. Like the pinning effect on MD walls, the emergence of vortex-like tadpole closure MDs upon the application of external magnetic field may be an origin of the AMR in La(0.69)Ca(0.31)MnO(3). PMID:20548105

Yu, Xiuzhen; Li, Run-Wei; Asaka, Toru; Ishizuka, Kazuo; Kimoto, Koji; Matsui, Yoshio

2010-08-01

323

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

NASA Astrophysics Data System (ADS)

A regional analysis of the anisotropy of the magnetic susceptibility (AMS) on chloritoid-bearing slates of the Paleozoic Plougastel Formation in the low-grade metamorphic conditions (epizonal) of the Monts d'Arrée slate belt in Central Armorica (Brittany, France) reveals very high values for the degree of anisotropy (PJ), up to 1.43 (Haerinck et al. 2013a). In contrast, stratigraphically equivalent slates free of chloritoid, in the very low-grade metamorphic conditions (anchizonal) of the Crozon fold-and-thrust belt, show a lower degree of anisotropy, with PJ values up to 1.27. Classically, very strong magnetic fabrics (i.e. those with PJ above 1.35) are attributed to a contribution of ferromagnetic (s.l.) minerals. Nonetheless, high-field torque magnetometry indicates that the magnetic fabric of the chloritoid-bearing slates is dominantly paramagnetic. The ferromagnetic (sensu lato) contribution to the AMS is less than 10%. Based on these observations, it would seem that chloritoid has an intrinsic magnetic anisotropy that is significantly higher than that of most paramagnetic silicates and the frequently used upper limit for the paramagnetic contribution to the AMS. Using two independent approaches, i.e. (a) directional magnetic hysteresis measurements, and (b) torque magnetometry, on a collection of single chloritoid crystals, collected from different tectonometamorphic settings worldwide, the magnetocrystalline anisotropy of monoclinic chloritoid has been determined (Haerinck et al. 2013b). The determined paramagnetic high-field AMS ellipsoids have a highly oblate shape with the minimum susceptibility direction subparallel to the crystallographic c-axis of chloritoid and the degree of anisotropy of chloritoid is found to be 1.47 ± 0.06. The obtained very high magnetocrystalline degree of anisotropy suggests that chloritoid-bearing slates with a pronounced mineral alignment can have a high degree of anisotropy (PJ) without the need of invoking a significant 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.

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

2014-05-01

324

Multilevel magnetization switching by electric field in c-axis oriented polycrystalline Z-type hexaferrite  

NASA Astrophysics Data System (ADS)

Direct and converse magnetoelectric (ME) effects, namely, magnetic-field (B) induced electric polarization (P) and electric-field (E) induced magnetization (M), respectively, were investigated at room temperature for c-axis oriented polycrystalline specimens of a Z-type hexaferrite, Sr3Co2Fe24O41. The B profile of the linear ME coefficient obtained from the converse effect well coincides with that obtained from the direct effect. Furthermore, M-E curves show a substantial hysteretic behavior, which allows reversal and multilevel switching of M by applying pulsed E. The present results demonstrate the feasibility of nonvolatile memory elements by using the ME Z-type hexaferrite at room temperature.

Okumura, K.; Haruki, K.; Ishikura, T.; Hirose, S.; Kimura, T.

2013-07-01

325

The Magnetic Field  

NSDL National Science Digital Library

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

Jeffrey Barker

326

Mapping Magnetic Fields  

NSDL National Science Digital Library

This is an activity about magnetism. Using bar magnets, classroom materials, and a compass, learners will explore how bar magnets interact with one another and with other materials, use a compass to find the direction north, and use various materials to make magnetic field lines visible around a bar magnet. This is an activity in a larger poster resource, entitled The Sun Like It's Never Been Seen Before: In 3D.

327

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

PubMed Central

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

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

2013-01-01

328

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

PubMed

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

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

2014-06-01

329

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

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

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

2014-01-01

330

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

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

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

331

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

PubMed Central

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

Guarendi, Andrew N.; Chandy, Abhilash J.

2013-01-01

332

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

PubMed Central

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

Sabatini, Angelo Maria

2011-01-01

333

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

PubMed Central

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

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

2011-01-01

334

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

SciTech Connect

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

Beek, D. van der; Petukhov, A.V.; Vroege, G.J.; Lekkerkerker, H.N.W. [Van't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute, Utrecht University, Padualaan 8, 3584 CH Utrecht (Netherlands); Davidson, P.; Ferre, J.; Jamet, J.P. [Laboratoire de Physique des Solides, UMR 8502 CNRS, Universite Paris-Sud, Batiment 510, 91405 Orsay (France); Wensink, H.H. [Institut fuer Theoretische Physik II, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstrasse 1, Gebaeude 25.32, 40225 Duesseldorf (Germany); Bras, W. [Netherlands Organisation for Scientific Research (NWO), DUBBLE CRG, European Synchrotron Radiation Facility, BP 220, 38043 Grenoble Cedex (France)

2006-04-15

335

Bats respond to polarity of a magnetic field  

PubMed Central

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. PMID:17848365

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

2007-01-01

336

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

PubMed

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

Sandberg; BACkman; Ottosson

1998-05-21

337

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

E-print Network

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

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

2010-06-30

338

Frustration and Entanglement in Compass and Spin-Orbital Models  

E-print Network

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

Andrzej M. Ole?

2014-10-24

339

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

NASA Astrophysics Data System (ADS)

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.

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

2013-11-01

340

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

NASA Technical Reports Server (NTRS)

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.

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

2011-01-01

341

Nuclear magnetic moment of 69As from on-line ?-NMR on oriented nuclei  

NASA Astrophysics Data System (ADS)

A precise value for the magnetic moment of the 69As 5/2- ground state has been obtained from nuclear magnetic resonance on oriented nuclei (NMR/ON) using the NICOLE 3He-4He dilution refrigerator setup at ISOLDE/CERN. The NMR/ON signal was observed by monitoring the anisotropy of the 69As ? particles. The center frequency ?[Bext=0.0994(10)T]=169.98(9) MHz corresponds to ?[69As]=+1.6229(16)?N. This result differs considerably from the ?f5/2 single-particle value obtained with g factors for a free proton but is in reasonable agreement with the value obtained with effective g factors and with values from a core polarization calculation and from calculations in the framework of the interacting boson-fermion model. Assuming a single exponential spin-lattice relaxation behavior a relaxation time T'1=10(25) s was observed for 69AsFe¯ at a temperature of about 20 mK in a magnetic field B=0.1 T.

Golovko, V. V.; Kraev, I. S.; Phalet, T.; Severijns, N.; Zákoucký, D.; Vénos, D.; Herzog, P.; Tramm, C.; Srnka, D.; Honusek, M.; Köster, U.; Delauré, B.; Beck, M.; Kozlov, V. Yu.; Lindroth, A.; Coeck, S.

2005-12-01

342

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

NASA Astrophysics Data System (ADS)

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

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

343

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

SciTech Connect

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.

Behera, B. C.; Ravindra, A. V.; Padhan, P. [Department of Physics, Indian Institute of Technology Madras, Chennai 600036 (India); Prellier, W. [Laboratoire CRISMAT, CNRS UMR 6508, ENSICAEN, 6 Bd du Marehal Juin, F-14050 Caen Cedex (France)

2014-03-03

344

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

PubMed

Many animal species, including some social hymenoptera, use the visual system for navigation. Although the insect compound eyes have been well studied, less is known about the second visual system in some insects, the ocelli. Here we demonstrate navigational functions of the ocelli in the visually guided Australian desert ant Melophorus bagoti. These ants are known to rely on both visual landmark learning and path integration. We conducted experiments to reveal the role of ocelli in the perception and use of celestial compass information and landmark guidance. Ants with directional information from their path integration system were tested with covered compound eyes and open ocelli on an unfamiliar test field where only celestial compass cues were available for homing. These full-vector ants, using only their ocelli for visual information, oriented significantly towards the fictive nest on the test field, indicating the use of celestial compass information that is presumably based on polarised skylight, the sun's position or the colour gradient of the sky. Ants without any directional information from their path-integration system (zero-vector) were tested, also with covered compound eyes and open ocelli, on a familiar training field where they have to use the surrounding panorama to home. These ants failed to orient significantly in the homeward direction. Together, our results demonstrated that M. bagoti could perceive and process celestial compass information for directional orientation with their ocelli. In contrast, the ocelli do not seem to contribute to terrestrial landmark-based navigation in M. bagoti. PMID:21346116

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

2011-03-15

345

Self-Compassion and Internet Addiction  

ERIC Educational Resources Information Center

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,…

Iskender, Murat; Akin, Ahmet

2011-01-01

346

Mindful Self-Compassion: Core Skills Training  

E-print Network

-compassion exercises to clients What To Expect Program activities include meditation, short talks, experiential.CenterForMSC.org Prerequisites No previous experience with mindfulness or meditation is required to attend the program for Meditation and Psychotherapy. He leads workshops internationally on mindfulness and self-compassion. Dr

Paulsson, Johan

347

Measurement of alternating magnetic properties of grain-oriented materials using a round rotational single sheet tester  

NASA Astrophysics Data System (ADS)

This paper presents a measurement of grain-oriented electrical steel under pure alternating magnetic flux condition at inclination angles from -90° to 90° with respect to the rolling direction (RD). The measurement was carried out using a round rotational single sheet tester. The results show a strong asymmetry of alternating power loss and magnetic field strength with respect to the RD. The alternating power loss depends on the side of the band where the specimen was cut off.

Gori?an, V.; Hamler, A.; Jesenik, M.; Štumberger, B.; Trlep, M.

2006-02-01

348

Spin echo and geometric phase of a central spin coupled to a compass spin-chain  

NASA Astrophysics Data System (ADS)

We investigate the Loschmidt echo of a quantum system where a central spin is symmetrically coupled to a compass spin-chain. It is found that the Loschmidt echo and its statistical distribution are able to detect the quantum criticality of the compass spin-chain at low temperature. By applying a spin flip operation to reverse the central spin's orientation, we find the controlled spin echo and its statistical distribution can effectively reveal quantum criticality at very high temperature. Moreover, we show that the geometric phase of a central spin can be used to indicate the quantum phase transition of a compass spin-chain and obeys scaling behavior in the vicinity of a quantum phase transition.

Wu, Wei; Luo, Da-Wei; Xu, Jing-Bo

2015-01-01

349

Changes in the composition and content of lipids in the leaves of radish plants of different magnetic orientation induced by weak permanent magnetic field  

Microsoft Academic Search

The effect of weak permanent horizontal magnetic field (PMF) with the intensity of 403 A\\/m on the composition and content\\u000a of polar and neutral lipids and their constituent FAs was investigated in the leaves of radish plants (Raphanus sativus L., var. radicula D.C.), cv. Rozovo-krasnyi s belym konchikom, which belong to two major types of magnetic orientation (TMO): North-South (NS)

G. V. Novitskaya; T. V. Feofilaktova; T. K. Kocheshkova; I. U. Yusupova; Yu. I. Novitskii

2008-01-01

350

Full-wave analysis of a wide class of microstrip resonators fabricated on magnetized ferrites with arbitrarily oriented bias magnetic field  

Microsoft Academic Search

A numerical code has. been developed for the full-wave determination of the resonant frequencies and quality factors of microstrip patches with right-angle corners of arbitrary shape in the case in which the substrate of the patches is a magnetized ferrite with arbitrarily oriented bias magnetic field. The code is based on the solution of an electric-field integral equation by means

Germán León; Rafael R. Boix; Francisco Medina

2002-01-01

351

Temperature Dependence of Magnetic Moment Orientation in Co2Z-Type Hexaferrite Estimated by High-Temperature Neutron Diffraction  

NASA Astrophysics Data System (ADS)

We investigated the correlation between the thermomagnetic curve of Co2Z-type hexagonal barium ferrite and its magnetic moment direction. We measured the thermomagnetic curve of Ba3Co1.8Fe24.2O41, prepared using the conventional solid-state reaction method, in the temperature range from 294 to 773 K with a vibrating sample magnetometer under 70 Oe. The curve shows two significant magnetization slumps at 540 K and 680 K. High-temperature XRD patterns show that no crystal transformation occurs in the temperature region from 294 to 773 K. High-temperature neutron diffraction experiments were performed to investigate the magnetic moment orientation at elevated temperatures. The Rietveld analyses of the neutron diffraction patterns indicate that the temperature rise from 523 to 573 K makes the magnetic moments turn to the c-axis from a direction parallel to the c-plane most significantly. The slump in magnetization at 540 K may be attributed to the change in easy magnetization direction from the c-plane to the c-axis. The change in average orientation of the magnetic moments must be induced by the disappearance of the contribution of cobalt to magnetism in this temperature range.

Takada, Yukio; Nakagawa, Takashi; Fukuta, Yasunari; Tokunaga, Masatoshi; Yamamoto, Takao A.; Tachibana, Takeshi; Kawano, Shinji; Igawa, Naoki; Ishii, Yoshinobu

2005-05-01

352

Magnetic moment of Ag104m and the hyperfine magnetic field of Ag in Fe using nuclear magnetic resonance on oriented nuclei  

NASA Astrophysics Data System (ADS)

Nuclear magnetic resonance (NMR/ON) measurements with ?- and ?-ray detection have been performed on oriented Ag104g,m nuclei with the NICOLE He3-He4 dilution refrigerator setup at ISOLDE/CERN. For Ag104g (I?=5+) the ?-NMR/ON resonance signal was found at ?=266.70(5) MHz. Combining this result with the known magnetic moment for this isotope, the magnetic hyperfine field of Ag impurities in an Fe host at low temperature (<1 K) is found to be |Bhf(AgFe)|=44.709(35) T. A detailed analysis of other relevant data available in the literature yields three more values for this hyperfine field. Averaging all four values yields a new and precise value for the hyperfine field of Ag in Fe; that is, |Bhf(AgFe)|=44.692(30) T. For Ag104m (I?=2+), the anisotropy of the ? particles provided the NMR/ON resonance signal at ?=627.7(4) MHz. Using the new value for the hyperfine field of Ag in Fe, this frequency corresponds to the magnetic moment ?(Ag104m)=+3.691(3) ?N, which is significantly more precise than previous results. The magnetic moments of the even-A Ag102-110 isotopes are discussed in view of the competition between the (?g9/2)7/2+-3(?d5/2?g7/2)5/2+ and the (?g9/2)9/2+-3(?d5/2?g7/2)5/2+ configurations. The magnetic moments of the ground and isomeric states of Ag104 can be explained by an almost complete mixing of these two configurations.

Golovko, V. V.; Kraev, I. S.; Phalet, T.; Delauré, B.; Beck, M.; Kozlov, V. Yu.; Coeck, S.; Wauters, F.; Herzog, P.; Tramm, Ch.; Zákoucký, D.; Vénos, D.; Srnka, D.; Honusek, M.; Köster, U.; Severijns, N.

2010-05-01

353

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

E-print Network

Magnetic-field-induced orientation of superconducting MgB2 crystallites determined by x-ray; published 4 August 2006 X-ray diffraction studies of fine polycrystalline samples of MgB2 the isotropic value =1 see Fig. 4 in Ref. 14 . Some experi- mental studies claim that the H T,H = T,H .12

Vakni, David

354

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

SciTech Connect

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.

Bret, A., E-mail: antoineclaude.bret@uclm.es [ETSI Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real, Spain and Instituto de Investigaciones Energéticas y Aplicaciones Industriales, Campus Universitario de Ciudad Real, 13071 Ciudad Real (Spain)

2014-02-15

355

Magnetic information calibrates celestial cues during migration.  

PubMed

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

Sandberg; Bäckman; Moore; Lõhmus

2000-10-01

356

Secondary recrystallization behavior and magnetic properties of grain oriented 2.2% Si-1.5% Mn steel  

NASA Astrophysics Data System (ADS)

The secondary recrystallization behavior and magnetic properties in ultralow carbon 2.2% Si-1.5% Mn steel containing 0.008% sol.Al was investigated. It was found that the atmosphere of final annealing plays an important role on the secondary recrystallization in this steel. In the case of annealing in N2 containing gas, good magnetic properties equivalent to those of conventional grain-oriented electrical steel were obtained. However, annealing in 100% H2 gas resulted in poor magnetic properties. Annealing in N2 containing gas can be considered as causing a sharp {110}<001? texture due to the strengthened inhibition resulting from an increase in fine nitrides. These results suggest the possibility of a new simple processing of grain-oriented electrical steel.

Yashiki, H.; Kaneko, T.

1993-05-01

357

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

PubMed

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

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

2014-07-01

358

Roe v. Wade. Reflective compassion.  

PubMed

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

Padovano, A T

1998-01-01

359

Mapping Magnetic Field Lines  

NSDL National Science Digital Library

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

2012-08-03

360

Circles of Magnetism I  

NSDL National Science Digital Library

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

The Exploratorium

2011-12-05

361

The quantum Zeno effect immunizes the avian compass against the deleterious effects of exchange and dipolar interactions.  

PubMed

Magnetic-sensitive radical-ion-pair reactions are understood to underlie the biochemical magnetic compass used by avian species for navigation. Recent experiments have provided growing evidence for the radical-ion-pair magnetoreception mechanism, while recent theoretical advances have unravelled the quantum nature of radical-ion-pair reactions, which were shown to manifest a host of quantum-information-science concepts and effects, like quantum measurement, quantum jumps and the quantum Zeno effect. We here show that the quantum Zeno effect provides for the robustness of the avian compass mechanism, and immunizes its magnetic and angular sensitivity against the deleterious and molecule-specific exchange and dipolar interactions. PMID:22142839

Dellis, A T; Kominis, I K

2012-03-01

362

The advanced stellar compass onboard the Oersted satellite  

NASA Technical Reports Server (NTRS)

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

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

1997-01-01

363

Orientation Errors in Paleomagnetic Core Samples and Their Effects  

NASA Astrophysics Data System (ADS)

In paleomagnetic studies, samples are often obtained as cylindrical cores by the use of engine drills. Two angles measured for the core in the field (the angle P between cylindrical axis and the horizontal plane, and the angle A between a horizontal direction in the core and the true north) are needed to describe the direction of magnetic remanence in geographic coordinates. These angles can be measured with an error of about 1 degree or less. The error in paleomagnetic directions are usually given by Fisher's semi-angle of 95% confidence (? 95), which is typically a few to ten degrees. It appears therefore that the orientation errors are negligibly small. However, this it not quite correct. There is no problem about the measurement of P, but the angle in the horizontal plane (A) is often measured by a magnetic compass, which is a source of large errors. In particular, large local magnetic anomalies often accompany volcanic rock terrain because of their strong magnetization. This effect is known quite a long time, but quantitative estimate of orientation errors is not available yet. We have obtained quite a large number of data (182 lavas, 903 samples) from Lundarhals area of Iceland. For more than 200 samples of these, three independent horizontal angles have been measured to estimate A; one by sun's direction, the second by reference to some landmark, and the third is by magnetic direction. Among the rest of samples, more than 600 have reference and magnetic directions. Only 30 samples are determined by magnetic compass alone. From a detailed analysis of these data, the following conclusions were obtained. (1) The difference between sun and reference azimuths are 0.0±0.6~circ (the mean and standard deviation in degrees, for n=203). This is small enough and can be ignored compared to other errors. Consequently, if either of these angles are available, we have almost error-free data for A. (2) The differences between the sun and magnetic azimuths are 0.5±7.8o (n=240), and those between the reference and magnetic azimuths are 0.0±6.9o (n=844). This error is not negligible in the paleosecular variation studies, in which the typical ASD is of the order of 10 to 20 degrees. (3) In general, samples from the same lava show similar errors. Thus it appears that the main reason for the error in A is the magnetization of the lavas itself. However, it is hard to find a good correlation between the direction of magnetization and the orientation errors.

Kono, M.

2011-12-01

364

Effect of the grain orientation in the material used for the preparation of an ultrathin electrical steel on its texture and magnetic properties  

NASA Astrophysics Data System (ADS)

The effect of initial orientation of samples on the magnetic properties and texture of ultrathin grain-oriented steel strips produced of them has been studied. In a number of cases, the samples with a larger initial deviation from the ideal (110)[001] orientation demonstrate a higher level of magnetic properties (if considering the total set of characteristics) in comparison with the samples with a small initial deviation. For the samples with a larger initial deviation, the final magnitudes of the magnetic induction obtained after the treatment exceed its initial magnitudes. Therefore, for producing an ultrathin grain-oriented electrical steel with high properties, a material with a scattered orientation of grains relative to the ideal (110)[001] orientation can be used.

Lobanov, M. L.; Redikul'Tsev, A. A.; Rusakov, G. M.; Kagan, I. V.; Pervushina, O. V.

2011-05-01

365

Preferred orientation of phyllosilicates as a control of magnetic fabric, example from easternmost Rheno-Hercynian Zone of Bohemian Massif  

NASA Astrophysics Data System (ADS)

The easternmost section of the Rheno-Hercynian Zone of the Bohemian Massif is built up of the Lower Carboniferous flysch sediments. The sedimentary sequences were deformed during Variscan orogeny. The ductile deformation, indicated by magnetic fabric, gradually increases from the east to the west. The deformation took place under the low-grade metamorphic conditions and led to the origin of the N-S striking folds and cleavage. The cleavage preferentially evolved in the incompetent shales and is less evident in the competent graywackes. In the most deformed sediments the magnetic fabric progressively changes from primary to secondary one, with magnetic foliation ranging from bedding parallel to cleavage parallel, respectively. The magnetic lineation is parallel to the bedding-cleavage intersection. The measurements of the temperature variations of magnetic susceptibility showed that the dominant carriers of magnetic properties are paramagnetic phyllosilicates, i.e. chlorites and micas. The neutron texture goniometry was applied to measure the preferred orientation of phyllosilicates. The neutron texture goniometry justified the use of the conventional AMS technique for deduction the rock fabric. The degree of magnetic anisotropy correlates well with the degree of phyllosilicate preferred orientation. In most cases the textures show girdle distributions of the c-axes normal to the lineation, sometimes with two distinct maxima. From the pole figures, the fabric ellipsoid was calculated in order to obtain the theoretical magnetic fabric. The parameters of theoretical fabric ellipsoid were compared with the parameters of AMS ellipsoid. The neutron texture goniometry was used to assess the origin of the deformational magnetic fabric which could be formed by the different phyllosilicate reorientation mechanisms, e.g. micro-folding or preferential growth of phyllosilicates under the anchi-metamorphic conditions possible in simple shear regime.

Chadima, M.; Günther, A.

2003-04-01

366

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

PubMed

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. PMID:22693032

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

2012-09-15

367

Magnetism  

NSDL National Science Digital Library

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

University Corporation for Atmospheric Research Windows to the Universe team

2007-12-12

368

Self-compassion and PTSD symptom severity  

Microsoft Academic Search

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

Brian L. Thompson; Jennifer Waltz

2008-01-01

369

Self-compassion and adaptive psychological functioning  

Microsoft Academic Search

Two studies are presented to examine the relation of self-compassion to psychological health. Self-compassion entails being kind and understanding toward oneself in instances of pain or failure rather than being harshly self-critical; perceiving one’s experiences as part of the larger human experience rather than seeing them as isolating; and holding painful thoughts and feelings in mindful awareness rather than over-identifying

Kristin D. Neff; Kristin L. Kirkpatrick; Stephanie S. Rude

2007-01-01

370

The origins of the Carolinian sidereal compass  

E-print Network

. (Head of Depa tment) May 1985 ABSTRACT The Origins of the Carolinian Sidereal Compass. (May 1985) Michael David Halpern, B. A. , University of California, Santa Cruz Chairperson of Advisory Committee: Dr. George F. Bass The sidereal compass... memories. ACKNGNLEDGMENTS I would like to thank Dr. Edwin Doran, Professor Emeritus of Geography at Texas A&M, for his early help and guidance. It was he who planted the seed that grew into this pro)ect. My Committee, for their encouragement, aid...

Halpern, Michael David

1985-01-01

371

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

PubMed

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

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

2013-10-01

372

Magnetic field sensor  

NASA Astrophysics Data System (ADS)

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

Silva, Nicolas

2012-09-01

373

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

SciTech Connect

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

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

2006-01-01

374

Temperature dependence of AC losses in a BSCCO/Ag tape exposed to AC magnetic fields applied in different orientations  

NASA Astrophysics Data System (ADS)

When high-temperature superconducting tapes are used in electrotechnical applications, they have an optimal working point in temperature. In the winding of e.g. a transformer the conductor carrying an AC current is exposed to an AC magnetic field oriented differently in separate parts of the winding. To determine the optimal working temperature it is essential to study the temperature dependence of the AC losses under these conditions. In this study, we present experimental results of the losses in a multi-filamentary silver-sheathed Bi-2223 high-temperature superconducting tape carrying an AC transport current in an AC magnetic field applied in different orientations perpendicular to the current path. The losses were measured calorimetrically in the temperature interval 40-85 K. The experimental results are compared to semi-empirical models of the AC losses.

Wolfbrandt, A.; Magnusson, N.; Hörnfeldt, S.

2002-08-01

375

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

SciTech Connect

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.

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

2014-04-28

376

Investigation on magnetic properties of orientated nanocomposite Pr2Fe14B/?-Fe permanent magnets by micromagnetic finite-element method  

NASA Astrophysics Data System (ADS)

Demagnetization curves for nanocomposite Pr2Fe14B/?-Fe permanent magnets with different hard grain alignment are calculated by a micromagnetic finite-element method. The results show that both remanence and coercivity increase with improving hard grains alignment. The demagnetization curves show a single-phase demagnetization behavior for the samples with grain size d of 10 nm and two-phase behavior for the samples with d of 20 and 30 nm. Hex (reflecting the magnetic hardening of ?-Fe) and Hirr (expressing the irreversible reversal of hard phase) are both enhanced with improving the hard grain alignment. The magnetic reversal in orientated nanocomposite permanent magnets is mainly controlled by inhomogeneous pinning of the nucleated type.

He, Shu-li; Zhang, Hong-wei; Rong, Chuan-bing; Chen, Juan; Sun, Ji-rong; Shen, Bao-gen

2012-11-01

377

Effect of Choline Chloride on the Lipid Content and Composition in the Leaves of Principal Magnetically-Oriented Radish Types  

Microsoft Academic Search

The effects of radish seed treatment with choline chloride on the number and weight of leaves, the weight of roots, as well as the content and composition of polar and neutral lipids and their component fatty acids in the leaves of principal magnetically-oriented types (MOTs) of radish (cv. Rosovo-krasnyi s belym konchikom), that is, North–South (NS) and West–East (WE) ones,

G. V. Novitskaya; T. K. Kocheshkova; T. V. Feofilaktova; Yu. I. Novitskii

2004-01-01

378

Effect of annealing prior to cold rolling on magnetic and mechanical properties of low carbon non-oriented electrical steels  

Microsoft Academic Search

The effects of annealing prior to cold rolling on the microstructure, magnetic and mechanical properties of low-C grain non-oriented (GNO) electrical steels have been investigated. The grain structure of hot-rolled electrical steel strips is modified by annealing at temperatures between 700 and 1050°C. Annealing at temperatures less than the ferrite to austenite+ferrite transformation temperature on heating (Ac1) causes a marginal

E. J. Gutiérrez-Castañeda; A. Salinas-Rodríguez

2011-01-01

379

The effect of Pt interlayers on the magnetic and structural properties of perpendicularly oriented barium ferrite media  

Microsoft Academic Search

Perpendicular barium ferrite (BaM) films with Pt interlayers were successfully fabricated. The magnetic and structural properties of BaM films were compared with BaM films without Pt interlayers. It was found that perpendicular c-axis orientation was greatly improved for films with Pt interlayers. Perpendicular remanent squareness is increased, and the c-axis dispersion angle Deltatheta50 is decreased with Pt interlayers in BaM

Zailong Zhuang; Maithri Rao; David E. Laughlin; Mark H. Kryder

1999-01-01

380

The effect of Pt interlayers on the magnetic and structural properties of perpendicularly oriented barium ferrite media  

Microsoft Academic Search

Perpendicular barium ferrite (BaM) films with Pt interlayers were successfully fabricated. The magnetic and structural properties of BaM films were compared with BaM films without Pt interlayers. It was found that perpendicular c-axis orientation was greatly improved for films with Pt interlayers. Perpendicular remanent squareness is increased, and the c-axis dispersion angle ??50 is decreased with Pt interlayers in BaM

Zailong Zhuang; Maithri Rao; David E. Laughlin; Mark H. Kryder

1999-01-01

381

Moisture movement and thickness swelling in oriented strandboard. Part 2: Analysis using a nuclear magnetic resonance imaging body scanner  

Microsoft Academic Search

The previous paper in this series demonstrates the use of a nuclear magnetic resonance (NMR) micro-imaging system to observe the movement of liquid water through small specimens (11  16 mm2 cross-section) of oriented strandboard (OSB) and solid wood. In the present paper, a NMR body scanner is utilized to obtain images of moisture penetration into ASTM D 1037–99 standard sized (152  152 mm2) thickness

Jeroen H. van Houts; Siqun Wang; Huiping Shi; George W. Kabalka

2006-01-01

382

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

ERIC Educational Resources Information Center

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…

Zerach, Gadi

2013-01-01

383

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

ERIC Educational Resources Information Center

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…

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

2007-01-01

384

Anisotropic electrical and magnetic properties of epitaxial Ga2-xFexO3 thin films with different crystalline orientations  

NASA Astrophysics Data System (ADS)

Anisotropy of electrical and magnetic properties in magnetoelectric and multiferroic materials is an important issue for applications of the materials to electronic devices. Ga2-xFexO3 (GFO) has been known as a pyroelectric ferrimagnet at room temperature when x > 1.4. GFO exhibits a permanent polarization along b-axis while a spontaneous net magnetization along c-axis. Exploration of its anisotropic properties requires preferentially oriented epitaxial thin films of GFO with different crystalline orientations. We have grown successfully b-axis oriented GFO thin films on indium-tin oxide(001)/yttria-stabilized zirconia(001). Two additional bottom electrodes such as SrRuO3 on SrTiO3(111), (110) and (100) and Pt(111)/Ti/SiO2/Si substrates were used for epitaxial growth of GFO. X-ray diffraction and transmission electron microscopy have been performed. Dielectric permittivity of the GFO films was measured with external magnetic field as a function of temperature. Local polarization switching behavior was characterized by scanning probe microscopy, which can give a clue to answer a debating question that GFO thin films are pyroelectric with no bistable switching states.

Hye Lee, Ji; Jo, William

2010-03-01

385

Magnetic monitoring of earth and space  

USGS Publications Warehouse

For centuries, navigators of the world's oceans have been familiar with an effect of Earth's magnetic field: It imparts a directional preference to the needle of a compass. Although in some settings magnetic orientation remains important, the modern science of geomagnetism has emerged from its romantic nautical origins and developed into a subject of great depth and diversity. The geomagnetic field is used to explore the dynamics of Earth's interior and its surrounding space environment, and geomagnetic data are used for geophysical mapping, mineral exploration, risk mitigation, and other practical applications. A global distribution of ground-based magnetic observatories supports those pursuits by providing accurate records of the magnetic-field direction and intensity at fixed locations and over long periods of time. ?? 2008 American Institute of Physics.

Love, J.J.

2008-01-01

386

Magnetic monitoring of earth and space  

USGS Publications Warehouse

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

Love, Jeffrey J.

2008-01-01

387

Cryptochromes Define a Novel Circadian Clock Mechanism in Monarch Butterflies That May Underlie Sun Compass Navigation  

Microsoft Academic Search

The circadian clock plays a vital role in monarch butterfly (Danaus plexippus) migration by providing the timing component of time-compensated sun compass orientation, a process that is important for successful navigation. We therefore evaluated the monarch clockwork by focusing on the functions of a Drosophila-like cryptochrome (cry), designated cry1, and a vertebrate-like cry, designated cry2, that are both expressed in

Haisun Zhu; Ivo Sauman; Quan Yuan; Amy Casselman; Myai Emery-Le; Patrick Emery; Steven M. Reppert

2008-01-01

388

Loving-Kindness and Compassion Meditation: Potential for Psychological Interventions  

PubMed Central

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

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

2011-01-01

389

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

390

Quantum dynamics of the avian compass  

NASA Astrophysics Data System (ADS)

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.

Walters, Zachary B.

2014-10-01

391

Quantum dynamics of the avian compass.  

PubMed

The ability of migratory birds to orient relative to the Earth's magnetic field is believed to involve a coherent superposition of two spin states of a radical electron pair. However, the mechanism by which this coherence can be maintained in the face of strong interactions with the cellular environment has remained unclear. This paper addresses the problem of decoherence between two electron spins due to hyperfine interaction with a bath of spin-1/2 nuclei. Dynamics of the radical pair density matrix are derived and shown to yield a simple mechanism for sensing magnetic field orientation. Rates of dephasing and decoherence are calculated ab initio and found to yield millisecond coherence times, consistent with behavioral experiments. PMID:25375526

Walters, Zachary B

2014-10-01

392

Dynamic Simulation of Radially Oriented Permanent Magnet-Type Electronically Operated Synchronous Machines with Parameters Obtained from Finite Element Field Solutions  

Microsoft Academic Search

A dynamic model for simulation of the transient interaction between radially oriented permanent magnet-type synchronous machines and their corresponding transistorized current source power conditioners is presented. Some key machine parameters used in this dynamic model were obtained from finite element field solutions. This dynamic model was used to obtain the transient interaction between a 15-hp samarium cobalt radially oriented permanent

Thomas W. Nehl; Fakhry A. Fouad; Nabeel A. Demerdash; Edward A. Maslowski

1982-01-01

393

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

PubMed

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

Michalec, Barret; Diefenbeck, Cynthia; Mahoney, Margaret

2013-04-01

394

3D Magnetic Flux Measurement in Joint Region of a Model Core Stacked with Grain-Oriented Electrical Steel  

NASA Astrophysics Data System (ADS)

Grain-oriented electrical steels show a high degree of anisotropy that favors magnetization in the rolling direction. Magnetization also occurs in other directions in the joint regions that are characterized by interlaminar flux. For direct measurement of such flux behavior, flat sensor elements that do not create additional air gaps have been developed. The present study carried out on a model core. To determine the local flux around the joint rejoin, thin Cu film elements were vapor-deposited on both sides of individual laminates. Normal flux components were detected by frame coil arrangements, and in-plane components were determined by films with tip contacts through the coating. The obtained results showed that in the joint regions, the incoming in-plane flux is converted to interlaminar flux in the overlap region, until a high degree of global saturation is reached; at this stage the flux through the air gaps between the laminates leads to more homogeneous magnetization.

Yamaguchi, Hiroi; Pfützner, Helmut; Ishida, Masayoshi

395

Preferred orientation and anisotropy of seismic and magnetic properties in gabbronorites from the Bushveld layered intrusion  

Microsoft Academic Search

The preferred orientation of plagioclase and pyroxene in gabbronorites from the Bushveld layered igneous intrusion (South Africa) was investigated using electron backscatter diffraction. In two localities 200 km apart (Belfast and Rustenburg) strong preferred orientation was observed with the principal fabric features aligned in the subhorizontal foliation plane (defined by (010) planes of plagioclase and (100) planes of pyroxene). The pattern

Joshua M. Feinberg; Hans-Rudolf Wenk; Gary R. Scott; Paul R. Renne

2006-01-01

396

Preferred orientation and anisotropy of seismic and magnetic properties in gabbronorites from the Bushveld layered intrusion  

Microsoft Academic Search

The preferred orientation of plagioclase and pyroxene in gabbronorites from the Bushveld layered igneous intrusion (South Africa) was investigated using electron backscatter diffraction. In two localities 200 km apart (Belfast and Rustenburg) strong preferred orientation was observed with the principal fabric features aligned in the subhorizontal foliation plane (defined by (010) planes of plagioclase and (100) planes of pyroxene). The

Joshua M. Feinberg; Hans-Rudolf Wenk; Gary R. Scott; Paul R. Renne

2006-01-01

397

First results from EBW emission diagnostics on COMPASS  

SciTech Connect

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

Zajac, J.; Preinhaelter, J.; Aftanas, M.; Bilkova, P.; Boehm, P.; Fuchs, V.; Weinzettl, V.; Zacek, F. [Institute of Plasma Physics AS CR, v.v.i., Association EURATOM/IPP.CR, Prague (Czech Republic); Urban, J. [Institute of Plasma Physics AS CR, v.v.i., Association EURATOM/IPP.CR, Prague (Czech Republic); CEA, IRFM, F-13108 Saint Paul-lez-Durance (France); Nanobashvili, S. [Andronikashvili Institute of Physics, Tamarashvili St. 6, 0177 Tbilisi (Georgia)

2012-10-15

398

Hadron Spectroscopy with COMPASS - Newest Results  

NASA Astrophysics Data System (ADS)

The COMPASS experiment at the CERN SPS investigates the structure and spectrum of hadrons by scattering high energetic hadrons and polarised muons off various fixed targets. During the years 2002-2007, COMPASS focused on nucleon spin physics using 160 GeV/c polarised µ+ beams on polarised deuteron and proton targets, including measurements of the gluon contribution to the nucleon spin using longitudinal target polarisation as well as studies of transverse spin effects in the nucleon on a transversely polarised target. One major goal of the physics programme using hadron beams is the search for new states, in particular the search for JPC exotic states and glue-balls. COMPASS measures not only charged but also neutral final-state particles, allowing for investigation of new objects in different reactions and decay channels. In addition COMPASS can measure low-energy QCD constants like, e.g. the electromagnetic polarisability of the pion. Apart from a few days pilot run data taken in 2004 with a 190 GeV/c ?- beam on a Pb target, showing a significant spin-exotic JPC = 1-+ resonance at around 1660 MeV/c2, COMPASS collected high statistics with negative and positive 190 GeV/c hadron beams on a proton (H2) and nuclear (Ni, Pb) targets in 2008 and 2009. We give a selected overview of the newest results and discuss the status of various ongoing analyses.

Nerling, Frank

2012-12-01

399

Compassion Fatigue among Social Work Students in Field Placements  

ERIC Educational Resources Information Center

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…

Harr, Cynthia; Moore, Brenda

2011-01-01

400

Self-Compassion and the Dynamics of Investigating Sexual Harassment  

ERIC Educational Resources Information Center

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…

Serri, Conchita Franco

2006-01-01

401

Compassion Fatigue and the Adult Protective Services Social Worker  

Microsoft Academic Search

Compassion fatigue is a relatively new term that describes the symptoms that are experienced by social workers and other helping professionals who work with clients experiencing trauma. This article defines the concept of compassion fatigue and relates compassion fatigue to Adult Protective Services (APS) social workers. It is proposed that APS social workers may be susceptible to the deleterious effects

Dara Bergel Bourassa

2009-01-01

402

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

PubMed

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. PMID:19590994

Craig, C D; Sprang, G

2010-05-01

403

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

SciTech Connect

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

Walbe, K.

1988-08-01

404

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

SciTech Connect

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

Sammarco, J.J.

1990-01-01

405

Mapping Magnetic Fields  

NSDL National Science Digital Library

This is an activity about bar magnets and their invisible magnetic fields. Learners will experiment with magnets and a compass to detect and draw magnetic fields. This is Activity 1 of a larger resource, entitled Exploring the Sun. The NASA spacecraft missions represented by this material include SOHO, TRACE, STEREO, Hinode, and SDO.

2012-08-03

406

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

NASA Astrophysics Data System (ADS)

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 church. The differences we found were bigger than the deviations we got from the comparisons to the geographic and magnetic east directions, so this indicates that practically the solar azimuth was not used for the church's direction. Furthermore, our investigations indicate that the orientation of the investigated churches is more likely to be related to the geographic east direction than to magnetic east.

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

2013-04-01

407

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

408

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

NASA Astrophysics Data System (ADS)

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.

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

409

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

DOE PAGESBeta

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

None

2013-09-04

410

Successive growth of Ba-ferrite magnetic layers on c -axis oriented YBaCuO superconductive layers  

SciTech Connect

Successive growth of Ba-ferrite (Ba{bold M}) layer on YBa{sub 2}Cu{sub 3}O{sub {ital x}} (YBCO) layer has succeeded by using facing targets sputtering (FTS) method, which is suitable for preparing oxide films. Ba{bold M} layer deposited on YBCO showed clear {ital c}-axis orientation of their crystallites normal to the film plane and they could be grown successively without interdiffusion. These bilayered films showed apparent perpendicular magnetic anisotropy originated from Ba{bold M} layer. Preferred {ital c}-axis orientation in Ba{bold M} layer could be clearly observed when its thickness was as small as 300 A.

Naoe, M.; Matsushita, N.; Nakagawa, S. (Department of Physical Electronics, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152 (Japan))

1991-11-15

411

Performance of large pixelised Micromegas detectors in the COMPASS environment  

NASA Astrophysics Data System (ADS)

New large-size Micromegas detectors are being developed for the future physics program of the COMPASS experiment at CERN. These detectors will have a pixelised readout in their center to detect particles in the beam region, where the particle flux can reach several MHz/cm2 in nominal conditions, and will have to handle high intensity hadron beams (up to a few 107 hadrons/s) with a discharge rate lower than 0.01 to 0.001 discharge/s. Several prototypes with two different discharge rate reduction technologies (preamplification stage with a GEM foil and resistive readout with buried resistors) have been studied in the COMPASS beam since 2010. Four of them have been included in the spectrometer since 2012, and have been used for the track reconstruction. Their performance (detection efficiency, space and time resolutions, and discharge rates) for different beam intensities and magnetic fields environments are presented. These detectors play an important role in the track reconstruction at very small angle; their impact is presented, with a particular emphasis on the effect of the background reduction due to an improved cluster selection.

Thibaud, F.; Abbon, P.; Andrieux, V.; Anfreville, M.; Bedfer, Y.; Burtin, E.; Capozza, L.; Coquelet, C.; Curiel, Q.; d'Hose, N.; Desforge, D.; Dupraz, K.; Durand, R.; Ferrero, A.; Giganon, A.; Jourde, D.; Kunne, F.; Magnon, A.; Makke, N.; Marchand, C.; Neyret, D.; Paul, B.; Platchkov, S.; Usseglio, M.; Vandenbroucke, M.

2014-02-01

412

Rise of pairwise thermal entanglement for an alternating Ising and Heisenberg spin chain in an arbitrarily oriented magnetic field  

NASA Astrophysics Data System (ADS)

Typically two particles (spins) could be maximally entangled at zero temperature, and for a certain temperature the phenomenon of entanglement vanishes at the threshold temperature. For the Heisenberg coupled model or even the Ising model with a transverse magnetic field, one can observe some rise of entanglement even for a disentangled region at zero temperature. So we can understand this emergence of entanglement at finite temperature as being due to the mixing of some maximally entangled states with some other untangled states. Here, we present a simple one-dimensional Ising model with alternating Ising and Heisenberg spins in an arbitrarily oriented magnetic field, which can be mapped onto the classical Ising model with a magnetic field. This model does not show any evidence of entanglement at zero temperature, but surprisingly at finite temperature rise a pairwise thermal entanglement between two untangled spins at zero temperature when an arbitrarily oriented magnetic field is applied. This effect is a purely magnetic field, and the temperature dependence, as soon as the temperature increases, causes a small increase in concurrence, achieving its maximum at around 0.1. Even for long-range entanglement, a weak concurrence still survives. There are also some real materials that could serve as candidates that would exhibit this effect, such as Dy(NO3)(DMSO)2Cu(opba)(DMSO)2 [DMSO = dimethyl sulfoxide; opba = o-phenylenebis(oxamoto)] [J. Stre?ka, M. Hagiwara, Y. Han, T. Kida, Z. Honda, and M. Ikeda, Condens. Matter Phys. 15, 43002 (2012), 10.5488/CMP.15.43002].

Rojas, M.; de Souza, S. M.; Rojas, Onofre

2014-03-01

413

Processing and enhanced piezoelectric properties of highly oriented compositionally modified Pb(Zr,Ti)O3 ceramics fabricated by magnetic alignment  

NASA Astrophysics Data System (ADS)

Highly oriented compositionally modified Pb(Zr,Ti)O3 (PZT) ceramics were successfully obtained by slip casting in a high magnetic field. PZT is a well-known superior ceramic with the highest piezoelectric properties, and these properties have been expected to be further improved through crystalline orientation. However, highly oriented PZT ceramics fabricated by slip casting in a high magnetic field have never been reported. We obtained oriented ceramics using compositionally modified PZT with Pb(Ni,Nb)O3, and their Lotgering factor was 0.77. The electromechanical coupling coefficient (k31) increased by 30%, and an extremely high value of 0.44 was achieved for the oriented ceramics.

Miwa, Yasunari; Kawada, Shinichiro; Kimura, Masahiko; Omiya, Suetake; Kubodera, Noriyuki; Ando, Akira; Suzuki, Tohru S.; Uchikoshi, Tetsuo; Sakka, Yoshio

2015-04-01

414

Variation of the degree of preferential crystallographic orientation and magnetic properties of texturized barium ferrite permanent magnets during sintering  

Microsoft Academic Search

1.A study was made of the effect of sintering temperature on the magnetic properties and demagnetization curves of anisotropic barium ferrite magnets along their texture axis and at right angles to it.2.It is shown that, during the sintering of texturized barium ferrite, its grains grow in a direction at right angles to the preferential direction of hexagonal axes and that

I. Yu. Gershov

1971-01-01

415

Developing compassion in pre-registration education.  

PubMed

Compassion is a fundamental aspect of nursing and student nurses have to be able to demonstrate compassion in practice. Nurse educators in higher education institutions and clinical settings need to work together to prepare and support student nurses to deliver compassionate care. This article discusses the key components of compassionate care, and how students can be enabled to deliver high-quality care within rapidly changing, complex environments. A second article in this issue explores how nurses can be recruited with the values of the 6Cs (page 12). PMID:25318150

Pryce-Miller, Maxine; Vernel, Emanuel

416

Program of COMPASS-II at CERN  

NASA Astrophysics Data System (ADS)

COMPASS collaboration has started in 2012 a five-year program of new measurements, which are outlined in the 'COMPASS-II' proposal. The two new major projects of the proposal are measurements of polarized Drell-Yan process in ?- scattering off transversely polarized protons and studies of GPDs via measurements of Deeply Virtual Compton Scattering and Hard Exclusive Meson Production in muon scattering off a liquid hydrogen target. In addition, high statistics SIDSI measurements with muon beams and a study of charged pion and kaon polarizabilities via Primakoff reactions with hadron beams are also foreseen as a part of this program.

Sandacz, A.

2015-02-01

417

Magnetic maps in animals: nature's GPS.  

PubMed

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. PMID:17951410

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

2007-11-01

418

Detrital remanent magnetization in the solar nebula  

E-print Network

We introduce the theoretical basis of a new form of remanent magnetization that likely formed on primitive bodies in the solar system. Accretional detrital remanent magnetization (ADRM) operates via “compass needle”-type ...

Fu, Roger Rennan

419

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

420

Magnetic Declination Calculator  

NSDL National Science Digital Library

This tool calculates magnetic declination for a variety of locations across Canada and elsewhere. Users select a city (Canada only) from a drop-down menu or enter latitude and longitude values (works for any location), and the tool calculates the proper magnetic declination (the angular difference between observed magnetic North on a compass and geographic or 'true' North). There are also links to information on how to use magnetic declination with a compass, and how to use the calculator to determine values of all seven magnetic components. For locations in Canada, the Canadian Geomagnetic Reference Field (CGRF) is used; for other locations, the International Geomagnetic Reference Field (IGRF) is used.

421

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

PubMed Central

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

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

2011-01-01

422

Effect of deformation and annealing on the microstructure and magnetic properties of grain-oriented electrical steels  

NASA Astrophysics Data System (ADS)

The effect of plastic deformation and subsequent annealing on the magnetic properties and microstructure of a grain-oriented (GO) electrical steel has been studied. True strain (?) from 0.002 to 0.23 was applied by rolling in two directions, rolling (RD) and transverse (TD). The deterioration of power losses varies according to the direction of deformation. Annealing the strained material—at 800 °C/2 h—leads to a recrystallization and restored magnetic properties. The main components of annealed-textures are around 15-35° from those of deformed-textures for both RD and TD. Rolling along {1 1 0} <0 0 1> direction leads to the development of deformation twins.

Castro, Nicolau A.; de Campos, Marcos F.; Landgraf, Fernando J. G.

2006-09-01

423

Vlf/elf radiation patterns of arbitrarily oriented electric and magnetic dipoles in a cold lossless multicomponent magnetoplasma.  

NASA Technical Reports Server (NTRS)

With the use of a power integral formulation, a study is made of the vlf/elf radiation patterns of arbitrarily oriented electric and magnetic dipoles in a cold lossless multicomponent magnetoplasma. Expressions for the ray patterns are initially developed that apply for arbitrary values of driving frequency, static magnetic-field strength, plasma density, and composition. These expressions are subsequently specialized to vlf/elf radiation in a plasma modeled on the magnetosphere. A series of representative pattern plots are presented for frequencies between the proton and electron gyrofrequencies. These patterns illustrate the fact that focusing effects that arise from the geometrical properties of the refractive index surface tend to dominate the radiation distribution over the entire range from the electron gyrofrequency to 4.6 times the proton gyrofrequency. It is concluded that focusing effects should be of significant importance in the design of a vlf/elf satellite transmitting system in the magnetosphere.

Wang, T. N. C.; Bell, T. F.

1972-01-01

424

Magnetic and other non-visual orientation mechanisms in some cave and surface urodeles  

Microsoft Academic Search

Animals adapted to light-deprived habitats might have improved non-visual sensory systems. Specimens of several cave-dwelling\\u000a species of urodeles spontaneously and persistently align to natural or artificially-modified permanent magnetic fields. Video\\u000a observations under dim infrared illumination revealed an obvious individual preference for one particular magnetic direction\\u000a in every animal tested. Therefore, animals changed alignments predictably when the horizontal magnetic field vector

Peter A. Schlegel

2008-01-01

425

Artifacts in the Wake: Leadership via an Oriented Compass Model  

ERIC Educational Resources Information Center

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…

Fallon, Paul D.

2013-01-01

426

Practical compassions: repertoires of practice and compassion talk in acute mental healthcare.  

PubMed

This article reports an exploratory study of the concept of compassion in the work of 20 mental health practitioners in a UK Midlands facility. Using notions of practice derived from phenomenology and Bourdieusian sociology and notions of emotional labour we identify two contrasting interpretive repertoires in discussions of compassion. The first, the practical compassion repertoire, evokes the practical, physical and bodily aspects of compassion. It involves organising being with patients, playing games, anticipating disruption and taking them outside for cigarettes. Practitioners described being aware that these practical, bodily activities could lead to patients 'opening up', disclosing their interior concerns and enabling practical, compassionate mental health work to take place. In contrast, the second, organisational repertoire, concerns organisational constraints on compassionate practice. The shortage of staff, the record-keeping and internal processes of quality control were seen as time-greedy and apt to detract from contact with patients. The findings are discussed in relation to Bourdieu and Merleau-Ponty's phenomenological accounts of practice and habit and set in context in the growing interest in placing compassion centrally in healthcare. We also explore how the exercise of compassion in the way our participants describe it can afford the more effective exercise of medical power. PMID:24117523

Brown, Brian; Crawford, Paul; Gilbert, Paul; Gilbert, Jean; Gale, Corinne

2014-03-01

427

Exploring Magnetic Fields in Your Environment  

NSDL National Science Digital Library

This is a lesson about measuring magnetic field directions of Earth and in the environment. First, learners go outside, far away from buildings, power lines, or anything electrical or metal, and use compasses to identify magnetic North. Next, they use the compasses to probe whether there are any sources of magnetic fields in the local environment, including around electronic equipment such as a CD player and speakers. This is the first lesson in the second session of the Exploring Magnetism teacher guide.

428

Anchor node localization for wireless sensor networks using video and compass information fusion.  

PubMed

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

Pescaru, Dan; Curiac, Daniel-Ioan

2014-01-01

429

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

PubMed Central

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

Pescaru, Dan; Curiac, Daniel-Ioan

2014-01-01

430

Advances in the neural bases of orientation and navigation  

Microsoft Academic Search

Synopsis The ability to locomote in one direction (oriented movement), and the ability to navigate toward a distant goal are related behaviors that are phylogenetically widespread. Orientation behaviors include finding the source of an odor or acoustic signal, using a sun-compass for guidance, and moving relative to fluid-dynamic cues. Such abilities might require little more than directionally selective sensors coupled

James A. Murray; Jessica Estepp; Shaun D. Cain

2006-01-01

431

A Moral Compass. For Parents Particularly.  

ERIC Educational Resources Information Center

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…

Klein, Helen Altman

2002-01-01

432

Tips for Disaster Responders: Understanding Compassion Fatigue  

MedlinePLUS

... signs of stress, talk with a friend or colleague, seek wise counsel from a trusted mentor, or ask your supervisor to help you determine a course of action. You may also consider seeking help from a qualified mental health professional. Tips for Coping With Compassion ...

433

Topographic Map and Compass Use. Student Manual.  

ERIC Educational Resources Information Center

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…

Taylor, Michael

434

46 CFR 184.402 - Compasses.  

Code of Federal Regulations, 2010 CFR

46 Shipping 7 2010-10-01 2010-10-01 false Compasses. 184.402 Section 184.402 Shipping...3) A vessel operating on short restricted routes on lakes, bays, and sounds. (c) Except on a vessel limited to...

2010-10-01

435

Influence of the interplanetary magnetic field orientation on polar cap ion trajectories - Energy gain and drift effects  

NASA Technical Reports Server (NTRS)

The influence of the interplanetary magnetic field (IMF) orientation on the transport of low-energy ions injected from the ionosphere is investigated using three-dimensional particle codes. It is shown that, unlike the auroral zone outflow, the ions originating from the polar cap region exhibit drastically different drift paths during southward and northward IMF. During southward IMF orientation, a 'two-cell' convection pattern prevails in the ionosphere, and three-dimensional simulations of ion trajectories indicate a preferential trapping of the light ions H(+) in the central plasma sheet, due to the wide azimuthal dispersion of the heavy ions, O(+). In contrast, for northward IMF orientation, the 'four-cell' potential distribution predicted in the ionosphere imposes a temporary ion drift toward higher L shells in the central polar cap. In this case, while the light ions can escape into the magnetotail, the heavy ions can remain trapped, featuring more intense acceleration (from a few electron volts up to the keV range) followed by precipitation at high invariant latitudes, as a consequence of their further travel into the tail.

Delcourt, D. C.; Horwitz, J. L.; Swinney, K. R.

1988-01-01

436

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

NASA Astrophysics Data System (ADS)

In-plane c-axis oriented Ba-hexaferrite (BaM) thin films were prepared on a-plane ( 11 2 ¯ 0 ) sapphire (Al2O3) 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 (Mr/Ms of 0.96) along the in-plane easy axis and low Mr/Ms 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 ( 10 1 ¯ 0 ) //?-Fe2O3 ( 11 2 ¯ 0 ) //Al2O3 ( 11 2 ¯ 0 ) .

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

2014-12-01

437

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

NASA Astrophysics Data System (ADS)

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 ?m 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 ?-fiber component, which lead to the high permeability.

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

2012-10-01

438

Flight results of the COMPASS-1 picosatellite mission  

NASA Astrophysics Data System (ADS)

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.

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

2010-11-01

439

Magnetically Aligned Bicelles To Study the Orientation of Lipophilic Ligands in Membrane Bilayers Jianxin Guo,  

E-print Network

the orientation and dynamic properties of two cannabinoids (8 -THC and Me-8 -THC) using 31 P and 2 H NMR be used to study the conformations of two lipophilic cannabinoids using high-resolution NMR through studied cannabinoids with respect to the bilayer normal based on measurements of residual quadrupolar

Yang, De-Ping

440

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

Microsoft Academic Search

Summary Displaced juvenile alligators,Alligator mississipiensis, were released on land in a 9 m diameter dodecagonal arena to test their ability to orient in the absence of terrestrial landmarks. Navigational ability seemed to improve with age. When displaced along a fairly direct route yearlings (age 7–14 months) compensated for their displacement, moving in the direction from the arena to their home

Gordon H. Rodda

1984-01-01

441

Measuring Earth's Magnetic Field Simply.  

ERIC Educational Resources Information Center

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)

Stewart, Gay B.

2000-01-01

442

Spin filtering in magnetic barrier structures with in-plane spin orientation  

NASA Astrophysics Data System (ADS)

We investigate ballistic spin transport in a two-dimensional electron-gas system containing magnetic barriers of various geometries by using the transfer matrix method. While most previous studies have focused on the effect of magnetic barriers perpendicular to the two-dimensional electron gas plane, we concentrate on the case of magnetic barriers parallel to the plane. We show that resonant oscillation occurs in the lower incident energy region in the transmission probability without any electrostatic potential compensation, which is an essential ingredient in the case of magnetic barriers perpendicular to the plane. The transmission probability in the magnetic barrier structure changes drastically according to the number of barriers and according to the additional electrostatic potential modulation applied in the magnetic barrier region. Using a hybrid model consisting of a superconductor, ferromagnets, and a two-dimensional electron gas plane, we show that the hybrid quantum structure can serve as a good spin filter, which can be operated totally by electrical modulation without any magnetic control.

Kim, Nammee; Kim, Heesang