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1

Lateralization of magnetic compass orientation in pigeons  

PubMed Central

The aim of our study was to test for lateralization of magnetic compass orientation in pigeons. Having shown that pigeons are capable of learning magnetic compass directions in an operant task, we wanted to know whether the brain hemispheres contribute differently and how the lateralization pattern relates to findings in other avian species. Birds that had learnt to locate food in an operant chamber by means of magnetic directions were tested for lateralization of magnetic compass orientation by temporarily covering one eye. Successful orientation occurred under all conditions of viewing. Thus, pigeons can perceive and process magnetic compass directions with the right eye and left brain hemisphere as well as the left eye and right brain hemisphere. However, while the right brain hemisphere tended to confuse the learned direction with its opposite (axial response), the left brain hemisphere specifically preferred the correct direction. Our findings demonstrate bilateral processing of magnetic information, but also suggest qualitative differences in how the left and the right brain deal with magnetic cues.

Wilzeck, Christiane; Wiltschko, Wolfgang; Gunturkun, Onur; Wiltschko, Roswitha; Prior, Helmut

2010-01-01

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.

Durif, Caroline M. F.; Browman, Howard I.; Phillips, John B.; Skiftesvik, Anne Berit; V?llestad, L. Asbj?rn; 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

2014-04-01

4

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

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

2014-06-01

6

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

7

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

8

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.

Workshop, Watsonville E.

2011-01-01

9

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.

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

2014-01-01

10

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

11

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

PubMed

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

2003-10-22

12

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.

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

2003-01-01

13

Magnetic Compass Dynamic Performance.  

National Technical Information Service (NTIS)

This paper describes the use of a fluxgate compass to provide accurate heading information for autonomous underwater vehicles. Two sources of error are identified: steady state bias and compass lag. Results of field tests comparing a fluxgate and a refere...

B. Bourgeois A. Martinez

1999-01-01

14

Light-dependent magnetic compass in Iberian green frog tadpoles  

Microsoft Academic Search

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\\u000a orientation under long-wavelength light (?500 nm) is due

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

2010-01-01

15

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

16

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.

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

2013-01-01

17

Adaptive and learning calibration of magnetic compass  

NASA Astrophysics Data System (ADS)

Magnetic compasses are widely used in vehicle navigation systems to measure the vehicle headings with respect to the Earth's magnetic north. Due to the local variation of the Earth's magnetic flux density and the induced magnetic field of the magnetized vehicle body, continuous calibrations of magnetic compasses are required to maintain accurate heading measurements. In this paper two different online compass calibration methods, one based on the parameter adaptation algorithm and the other based on the functional learning algorithm, are developed to achieve online self-calibration function for a flux-gate compass using GPS heading measurements as reference signals. Simulation and experiment results show that the algorithms are effective in removing the magnetic biases and providing a reliable method to improve the magnetic compass performance.

Kao, Wei-Wen; Tsai, Chin-Lang

2006-11-01

18

GEOMAGNETIC ORIENTATION OF LOGGERHEAD SEA TURTLES: EVIDENCE FOR AN INCLINATION COMPASS  

Microsoft Academic Search

Summary Recent experiments have demonstrated that hatchling loggerhead sea turtles can orient using the earth's magnetic field. To investigate the functional characteristics of the loggerhead magnetic compass, we tested the orientation of hatchlings tethered inside a circular arena surrounded by a coil system that could be used to reverse the vertical and horizontal components of the ambient field. Hatchlings tested

PHILLIP LIGHT; MICHAEL SALMON; KENNETH J. LOHMANN

1993-01-01

19

Learning of magnetic compass directions in pigeons  

Microsoft Academic Search

A proof of magnetic compass learning by pigeons under laboratory conditions has been attempted for decades, but all experiments\\u000a have failed so far. The aim of the present study was to test whether pigeons can learn magnetic compass directions in an operant\\u000a chamber if magnetic cues are presented as true spatial cues. Experimental sessions were carried out in the local

Christiane Wilzeck; Wolfgang Wiltschko; Onur Güntürkün; Jens-Uwe Buschmann; Roswitha Wiltschko; Helmut Prior

2010-01-01

20

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

21

nCompass Service Oriented Architecture for Tacit Collaboration Services  

NASA Astrophysics Data System (ADS)

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

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

22

Compass Games: An Introduction to Orienteering Skills  

ERIC Educational Resources Information Center

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

Sension-Hall, Debra

2011-01-01

23

Learning of magnetic compass directions in pigeons.  

PubMed

A proof of magnetic compass learning by pigeons under laboratory conditions has been attempted for decades, but all experiments have failed so far. The aim of the present study was to test whether pigeons can learn magnetic compass directions in an operant chamber if magnetic cues are presented as true spatial cues. Experimental sessions were carried out in the local geomagnetic field and in magnetic fields with matched total intensity and inclination, but different directions generated with Helmholtz-coils. Birds demonstrated successful learning with a performance level comparable to that in learning studies with magnetic anomalies. In addition, we compared the data from magnetic learning in the laboratory with performance from homing experiments in the field. The birds that were more successful in the learning experiment had vanishing bearings farther away from the home direction than the group mean at unfamiliar, but not at familiar sites. This might suggest that better learners explore unknown locations in a different way. Our findings represent the first evidence for operant magnetic compass learning in pigeons and also provide a link between behavioural data from the field and the laboratory. PMID:19937359

Wilzeck, Christiane; Wiltschko, Wolfgang; Güntürkün, Onur; Buschmann, Jens-Uwe; Wiltschko, Roswitha; Prior, Helmut

2010-05-01

24

Avian magnetic compass can be tuned to anomalously low magnetic intensities  

PubMed Central

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.

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

2013-01-01

25

Magnetism before Gilbert - Discovery of the Magnetic Compass  

NSDL National Science Digital Library

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

Stern, David

2005-04-27

26

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

27

The quantum compass chain in a transverse magnetic field  

Microsoft Academic Search

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,

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

2011-01-01

28

Applications of magnetic sensors for low cost compass systems  

Microsoft Academic Search

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

Michael J. Caruso

2000-01-01

29

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

30

Modeling Compassion in Critical, Justice-Oriented Teacher Education  

ERIC Educational Resources Information Center

As the work of teacher education becomes increasingly focused on the challenges of helping mostly white, monolingual, middle-class prospective teachers become compassionate, successful teachers of racially, culturally, linguistically, economically, and academically diverse students, some teacher educators struggle to find compassion for the…

Conklin, Hilary Gehlbach

2008-01-01

31

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.

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

2010-01-01

32

Measuring Magnetic Declination With Compass, GPS and Virtual Globes  

NASA Astrophysics Data System (ADS)

Using virtual globe (VG) imagery to determine geographic bearing and a compass to determine magnetic bearing yielded acceptable experimental magnetic declination values for large linear physical features at 13 sites in the western continental United States. The geographic bearing of each feature was determined from measurements involving the latitude/longitude coordinate system associated with the VG image (from World Wind or Google Earth). The corresponding magnetic bearing was measured on the ground at the feature with a hand-bearing compass calibrated in 1-degree subdivisions. A sequence of GPS trackpoints, recorded while traveling along the feature either in an automobile or on foot, unambiguously identified the pertinent portion of the feature (a straight segment of a road, for example) when plotted on the VG image. For each physical feature located on a VG image, its geographic bearing was determined directly using on-screen measurement tools available with the VG program or by hand using ruler/protractor methods with printed copies of the VG image. An independent (no use of VG) geographic bearing was also extracted from the slope of a straight-line fit to a latitude/longitude plot of each feature's GPS coordinates, a value that was the same (to within the inherent uncertainty of the data) as the VG-determined bearing, thus validating this procedure for finding geographic bearings. Differences between the VG bearings and the magnetic bearings yielded experimental magnetic declination values within one degree (8 within 0.5 degree) of expected values. From the point of view of physics and geophysics pedagogy, this project affords students a simple magnetism/geodesy field experiment requiring only a good compass and a GPS receiver with memory and a data port. The novel and straightforward data analysis with VG software yields reliable experimental values for an important abstract geophysical quantity, magnetic declination. Just as the compass has long provided easy access to Magnetic North, the coordinate systems inherent in recently-developed VG and GPS satellite technologies now provide easy access (i.e., no astronomical measurements involving Polaris or the Sun) to Geographic North for this and future applications.

O'Brien, W. P.

2006-12-01

33

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

34

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

PubMed

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

Efimova, Olga; Hore, P J

2008-03-01

35

Quantum Probe and Design for a Chemical Compass with Magnetic Nanostructures  

Microsoft Academic Search

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

Jianming Cai

2011-01-01

36

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

37

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

38

Accurate Ocean Current Observation near the magnetic dip pole: compass error estimation  

NASA Astrophysics Data System (ADS)

Accurate ocean current measurements near the magnetic dip pole have been carried out in the multi-year ice area of the central Arctic Ocean using ice-drifting buoy, J -CAD (JAMSTEC Compact Arctic Drifter). Because of weakness of the magnetic direction reference near the magnetic dip pole, we need to look more carefully into the compass malfunction in order to obtain accurate ocean current. Using the observational data from J-CAD 6 in 2003, we attempted heading data comparisons of attached compasses with azimuthal data calculated from GPS buoys. Results show that Watson Compass, which is 3-dimensional magneto-metric compass attached on the same cage of WorkHorse 300 kHz ADCP (WH-ADCP), can measure the correct heading with an accuracy of 4 degree over the entire J-CAD 6 trajectory. On the other hand, we found that WH-ADCP compass illustrated good results of heading measurements under the condition which the horizontal magnetic intensity is higher than 3000 nT. Also, we investigated a non-linear response of WH-ADCP compass from a comparison with Watson Compass, which are attached on J-CAD 4 in 2002. A non-linearity response of WH-ADCP compass was found with amplitude of ~20 degrees under the condition which the horizontal magnetic intensity is higher than 3000 nT. However, we can conclude that the heading data from WH-ADCP would be useful with an accuracy of 5 degrees after understanding the non-linear response of each compass.

Kikuchi, Takashi; Uno, Hirokatsu; Hosono, Masuo; Hatakeyama, Kiyoshi

39

Calibration of sonobuoy compass via arrival time inversion  

Microsoft Academic Search

Onboard magnetic compasses allow sonobuoys to measure their orientation and form beams along true headings. Compass failure means true array heading is unknown and the buoy's beams cannot be used for target localization and tracking. We describe a method for recovering buoy orientation by inverting the pattern of signal arrivals at the individual hydrophones, and present results using data recorded

K. J. Delaney; J. M. Alsup; P. Sullivan

2003-01-01

40

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

41

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

NASA Astrophysics Data System (ADS)

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

Wallace, Douglas G.; Martin, Megan M.; Winter, Shawn S.

2008-06-01

42

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

PubMed

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

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

2014-04-01

43

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

44

Role of Exchange and Dipolar Interactions in the Radical Pair Model of the Avian Magnetic Compass  

Microsoft Academic Search

It is not yet understood how migratory birds sense the Earth's magnetic field as a source of compass information. One suggestion is that the magnetoreceptor involves a photochemical reaction whose product yields are sensitive to external magnetic fields. Specifically, a flavin-tryptophan radical pair is supposedly formed by photoinduced sequential electron transfer along a chain of three tryptophan residues in a

Olga Efimova; P. J. Hore

2008-01-01

45

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

Microsoft Academic Search

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

Thorsten Ritz

2011-01-01

46

Quantum probe and design for a chemical compass with magnetic nanostructures.  

PubMed

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. PMID:21469779

Cai, Jianming

2011-03-11

47

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

48

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

49

Development of micro-fluxgate sensors with electroplated magnetic cores for electronic compass  

Microsoft Academic Search

Micromachined electronic compass integrating two-axis micro-fluxgate sensors was investigated. These sensors were perpendicularly aligned to measure the magnitude of X- and Y-axis magnetic fields, respectively and each of them was composed of rectangular-ring shaped magnetic core, solenoid excitation (49 turns), and pick-up (46 turns) coils. Excitation and pick-up coil patterns, which were formed opposite to each other, wound the magnetic

Hae-Seok Park; Jun-Sik Hwang; Won-Youl Choi; Dong-Sik Shim; Kyoung-Won Na; Sang-On Choi

2004-01-01

50

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.

Wyeth, Russell C.

2010-01-01

51

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

52

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.

53

Vehicle Detection and Compass Applications using AMR Magnetic Sensors  

Microsoft Academic Search

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

Michael J. Caruso; Lucky S. Withanawasam

54

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."

Society, American P.

2009-01-01

55

Quantum phase transition of the one-dimensional compass model in a transverse magnetic field  

Microsoft Academic Search

The quantum phase transition (QPT) of the one-dimensional (1D) quantum compass model in a transverse magnetic field is studied in this paper. An exact solution is obtained by using an extended Jordan and Wigner transformation to the pseudo-spin operators. The fidelity susceptibility, the concurrence, the block-block entanglement entropy, and the pseudo-spin correlation functions are calculated with antiperiodic boundary conditions. The

Ke-Wei Sun; Qing-Hu Chen

2009-01-01

56

One-Dimensional Quantum Compass Model in an Out-plane Magnetic Field  

Microsoft Academic Search

The one-dimensional quantum compass model (1D-QCM) in an out-plane magnetic field is investigated by numerical and analytical\\u000a methods. The presence of the 1D-QCM in an area of the ground-state magnetic phase diagram where the odd couplings are antiferromagnetic\\u000a and larger than the even couplings is studied. Using pseudo spin ladder operators indicates that the 1D-QCM in an out-plane\\u000a magnetic field

M. Motamedifar; Saeed Mahdavifar; S. Farjami Shayesteh

2011-01-01

57

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.

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

2010-01-01

58

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

59

Evaluation of nuclear quadrupole interactions as a source of magnetic anisotropy in the radical pair model of the avian magnetic compass  

Microsoft Academic Search

One of the principal proposed biophysical mechanisms put forward to explain the avian magnetic compass sense centres around magnetically sensitive chemistry. Based on a large number of in vitro studies of the effects of applied magnetic fields on the yields and rates of chemical reactions it has been suggested that the anisotropic magnetic interactions in spin-correlated radical pairs could be

Olga Efimova; P. J. Hore

2009-01-01

60

A subterranean mammal uses the magnetic compass for path integration  

PubMed Central

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

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

2004-01-01

61

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

SciTech Connect

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

Na, Kyoung-Won; Yuan, Jingli; Ji, Joon-Ho; Choi, Sang-On [Nano Fabrication Center, Samsung Advanced Institute of Technology (SAIT) (Korea, Republic of); MEMS Laboratory, Samsung Advanced Institute of Technology (SAIT) (Korea, Republic of)

2006-04-15

62

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

63

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

64

Magnetically guiding and orienting integrated chemical sensors  

NASA Astrophysics Data System (ADS)

Fluorescent microsensors for detecting pH and oxygen were positioned and oriented using magnetic tweezers. These multifunctional integrated microsensors were fabricated by physically linking together nano-components including magnetic nanoparticles, fluorescent nanoparticles, and metal hemisphere-shells. Two such microsensors are magnetic roll-shaped polystyrene particles with 120 nm fluorescent oxygen-sensing ormosil nanospheres that are physically pressed ("breaded") into the roll surface, and 4–5 µm fluorescent microspheres that are capped with a 50 nm thick metal hemispherical shell. The magnetic tweezers consisted of an iron wire that was magnetized in an external magnetic field. Rotating this external field oriented and rotated the microsensors.

Anker, Jeffrey N.; Lee, Yong-Eun Koo; Kopelman, Raoul

2014-08-01

65

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.

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

1987-01-01

66

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

PubMed

Identifying the mechanism in birds that controls magnetic orientation behavior is proving elusive and is currently attracting a plethora of research activity. Much of this research involves wild birds that are caught in nets, tested and released. Ethical concerns regarding these experiments are likely to encompass the welfare of animals, their "rights" and conservation issues. Recently, Pekin ducks derived from migratory ancestors have been shown to posses a magnetic compass in a simple conditioning procedure. The use of domestic bird species provides a refinement in the ethics of animal experimentation since these birds are not caught in nets, are less fearful of humans and their use does not raise conservation concerns. The study of magnetic orientation is a high profile and fascinating areas of animal behavior research and one in which behavioral scientists should be seen to actively embrace the principles of the 3R's. PMID:21509188

Freire, Rafael

2011-01-01

67

Clinical compassion.  

PubMed

Sometimes, people coming into specialist palliative care units unexpectedly improve with simple, compassionate care. Is this a mystery? Or does compassion directly affect human biology in ways we are only just beginning to understand? There is a widespread belief that kindness and compassion matter. They are what we would want for ourselves, or our loved ones; central, across religions and across cultures; taken as "given" by patients and families; and required by NHS constitution. Yet they are often absent, education and policy documents, and from clinical care settings. Educating for compassion remains an uncertain art. A Masters thesis, (awarded a distinction by the University of Oxford, 2010) explores the biological impact of compassion on the brain and the body, including its effects on the ?-opioid receptor system and the autonomic nervous system, as well as its observable effects on distress. Compassion switches on the ?-opioid receptor system. Compassion directly affects the human body in ways that are conducive to healing and wellbeing. Moreover, the neural circuits of compassion are contagious via the mirror neuron system and they can be trained and developed using the brains inherent capacity to remodel its neural circuits with practice (neuroplasticity). A simple model of the neural basis of the primary compassion pathway, and its positive and negative modulators gives a starting point for developing more effective educational and organisational strategies for compassion. One promising approach to developing compassion is by using mindfulness training, such as mindfulness based cognitive therapy (MBCT). A small pilot study of MBCT training for Hospice at Home nurses shows acceptability, and measurable impact on wellbeing, self compassion and clinical empathy. Could this be one way of re-prioritising compassion in healthcare systems? PMID:24653311

Palmer, Eileen

2011-09-01

68

46 CFR 28.230 - Compasses.  

Code of Federal Regulations, 2013 CFR

...Vessels That Operate Beyond the Boundary Lines or With More Than 16 Individuals On Board, or for Fish Tender Vessels Engaged in the Aleutian Trade § 28.230 Compasses. Each vessel must be equipped with an operable magnetic steering compass with a compass...

2013-10-01

69

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...

2009-07-20

70

Coupled Compass Oscillations Video Analysis Activity  

NSDL National Science Digital Library

This experiment explores the behavior of a pair of loosely coupled compass needles in air with weak damping. The needles are far enough apart that the magnetic interaction between their magnetic dipoles is much weaker than their interaction with the Earth's magnetic field. The resulting motion displays beats--when one compass is momentarily at rest, the other oscillates with maximum amplitude.

Figueira, Jalves

2014-06-28

71

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

72

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

73

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

74

Attitude compensated electronic compass for aircraft navigation  

Microsoft Academic Search

A magnetic compass has been developed by the Research Laboratory for Avionics System of the University of Florida intended to replace the common mechanical directional gyroscope for aircraft heading indication. The compass is based on an assembly of three mutually orthogonal single-core magnetic sensors, affixed to the fuselage, thus remaining in the aircraft frame of reference. The sensor electronics incorporate

G. Basile; M. Pierantoni; S. Pirani; M. Rinaldi; S. Varosi

1994-01-01

75

Compassion: an evolutionary analysis and empirical review.  

PubMed

What is compassion? And how did it evolve? In this review, we integrate 3 evolutionary arguments that converge on the hypothesis that compassion evolved as a distinct affective experience whose primary function is to facilitate cooperation and protection of the weak and those who suffer. Our empirical review reveals compassion to have distinct 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

2010-05-01

76

Oriented atoms in weak magnetic fields  

Microsoft Academic Search

This article reviews the early investigations of Series on the resonance absorption and fluorescence of light by samples of oriented atoms dagger subjected to static and oscillatory magnetic fields. These investigations include experiments on optical-radiofrequency double resonance, light beats in double resonance, circulation of coherence in optical pumping, and time-biasing in level-crossing spectroscopy. It then describes some selected laser spectroscopy

Peter Hannaford

1997-01-01

77

Preferred Orientation in Nanocomposite Permanent Magnet Materials  

Microsoft Academic Search

Melt-spun (Nd11.4Fe82.9B5.7)0.99M1 ribbons (M = Zr, Nb, Ga, Zr + Ga, Nb + Ga) were prepared by melt-spinning technique. Ga addition is found to be effective for the orientation of c-axis of Nd2Fe14B grains perpendicular to the ribbon plane. Better magnetic properties can be achieved by adding both the two kinds of elements Zr + Ca, Nb + Ca, and

Lijia Pang; Guangfei Sun; Jufang Chen; Wenjiang Qiang; Wenan Li; Jinbiao Zhang

2006-01-01

78

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

79

A PURPOSE ORIENTED MAGNETIC SEPARATOR: SKIMMER  

SciTech Connect

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

Salih Ersayin

2005-08-09

80

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

1986-01-01

81

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

82

On the Orientation of Magnetic Flux Ropes  

NASA Astrophysics Data System (ADS)

We have examined 2(1)/(2)D static magnetic flux rope configurations (? /? t ? 0, ? /? z ? 0, but Bz!= 0, z being the flux-rope axis) to determine their axis orientations from single-spacecraft data taken as the flux rope convects past the spacecraft. In a proper frame of reference, (x,y,z), the spacecraft trajectory projected onto the transverse (x-y) plane is a straight line along x across the flux rope structure. The distance from the center of the flux rope to the spacecraft trajectory is defined as the impact parameter. We have developed a multi-step, composite magnetic variance analysis method (the HS method) to accurately determine the axis of flux rope structures having right-left symmetry such as the Lundquist model of an axially symmetric force-free configuration. We will present the results of our analysis for right-left symmetric flux rope models of circular, elliptical and non-elliptical cross-sections (in the x-y plane) for comparison with results from Lepping's method [Lepping et al., 1990], in which the intermediate variance direction, obtained from magnetic variance analysis on unit normalized magnetic vectors (i.e., B), is used as the approximation for the true axis of the Lundquist model. Under certain conditions, our method yields the exact axis orientation, while the result from Lepping's method shows increasing angular error with increasing impact parameter. More general cases of non-symmetric, static flux-rope structures can also be analyzed, since they (as well as the symmetric cases) are governed by the Grad-Shafranov equation, ? t2A=-? 0dPt/dA, where the magnetic potential A is used to describe transverse magnetic field, Bx=? A/? y and By=-? A/? x, and Pt(A)=p(A)+Bz2(A)/2?0. For these asymmetric cases, the determination of the optimal axis orientation is accomplished by searching for the minimum in the fitting residue of Pt(A) subject to certain constraints. This method does not give a unique answer for structures that are right-left symmetric. Examples are presented to illustrate the procedures, to highlight pitfalls, and to show estimates.

Hu, Q.; Sonnerup, B. U.

2001-05-01

83

MAGNETIC ORIENTATION BY HATCHLING LOGGERHEAD SEA TURTLES (CARETTA CARETTA)  

Microsoft Academic Search

Summary Laboratory experiments were conducted to test the ability of loggerhead sea turtle hatchlings (Caretta caretta L.) to orient using the magnetic field of the earth. Hatchlings were tethered to a rotatable lever-arm apparatus which tracked swimming orientation in complete darkness. Hatchlings tested in the earth's magnetic field were nonrandomly oriented with a mean angle of 42°; those tested under

KENNETH J. LOHMANN

1991-01-01

84

The COMPASS future: COMPASS II  

NASA Astrophysics Data System (ADS)

Up to now the COMPASS experiment of Abbon et al. (2007) [8] contributed with the muon beam to precise measurements of the nucleon longitudinal momentum structure. A more complete nucleon description beyond collinear approximation includes the quark intrinsic momentum distributions which are described by the Transverse Momentum Dependent (TMD) Parton Distribution Functions (PDFs) and by Generalised Parton Distributions (GPDs). The next phase COMPASS Coll., (2010) [6] approved in December 2010 focuses on GPDs measurements through Deep Virtual Compton Scattering (DVCS) and Deep Virtual Meson Production (DVMP), in TMDs with Drell-Yan process and on Primakoff measurements. The latter shed light on the hadron structure through the hadron deformation in an external electromagnetic field described by the polarisabilities.

Rocco, E.

2012-04-01

85

Compassion fatigue in nurses  

Microsoft Academic Search

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

Elizabeth A. Yoder

2010-01-01

86

COMPASS Overview  

SciTech Connect

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

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

2007-06-13

87

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

NASA Astrophysics Data System (ADS)

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 ?-Fe2O3 dispersed in a solid methanol polymer matrix. The material was prepared by freezing a methanol-based ferrofluid of ?-Fe2O3 and subjecting it to a magnetic field applied in alternate directions to anneal the matrix. Before the field treatment, the solid displays magnetic behavior characteristic of an ordinary nanoscopic magnetic material. It is superparamagnetic above the blocking temperature (160 K) and hysteretic below, showing magnetic remanence and coercivity. After the field treatment to anneal the matrix, the same solid shows only Curie-Weiss behavior above and below the blocking temperature over the temperature range from 4.2 to 200 K and in response to applied magnetic fields as low as 1.59 kA/m. The data are consistent with a solid containing rotationally free, nanoscopic magnets encased in cavities of very small dimensions. The free rotation of the particles precludes the observation of magnetic relaxation phenomena that are characteristic of magnetic solids and ferrofluids. The present solid portends a class of magnetic materials with very little or no electrical and magnetic loss.

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

2000-06-01

88

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

89

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

90

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

91

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.

92

Optimal Coil Orientation for Transcranial Magnetic Stimulation  

PubMed Central

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

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

2013-01-01

93

Detection of alterations in human sperm using magnetic orientation techniques  

NASA Astrophysics Data System (ADS)

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

Sakhnini, Lama; Dairi, Maheen; Manaa, Hacene

2007-10-01

94

Sun compass error model  

NASA Technical Reports Server (NTRS)

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

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

1971-01-01

95

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

96

Orienting Paramecium with intense static magnetic fields  

Microsoft Academic Search

Recent experiments on cell division suggest the application of intense static magnetic fields as a novel tool for the manipulation of biological systems [1]. The magnetic field appears to couple to the intrinsic anisotropies in the diamagnetic components of the cells. Here, we present measurements of the intrinsic average diamagnetic anisotropy of the whole single celled ciliate, Paramecium Caudatum. Magnetic

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

2004-01-01

97

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

98

Creating moments that matter: strategies to combat compassion fatigue.  

PubMed

Understanding compassion fatigue and devising and implementing interventions to address the subject are important for nurses and patients. However, few literature reports exist that address interventions for nurses who experience compassion fatigue. This article discusses how nurses on a medical-surgical oncology unit in an academic, community Magnet™ hospital adopted these themes as a conceptual framework on which to focus actions to avoid and mitigate compassion fatigue. PMID:24305477

Reimer, Nicole

2013-12-01

99

Orientation of lipid tubules by a magnetic field.  

PubMed Central

Lipid tubules, which are straight hollow cylinders consisting of lipid bilayers, are shown to orient in strong magnetic fields. Birefringence measurements were made of dilute samples of tubules of 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphocholine (DC23PC) in magnetic fields of up to 4 T. The tubules were found to orient with their long axes parallel to the field direction, with saturated orientation [P2 (cos theta] approximately greater than 0.95) found at approximately 2 T. From known distributions of lengths and the number of bilayers in the walls, a value delta chi = (-7 +/- 1) X 10(-9) erg cm-3 G-2 was calculated for the tubules, which compares well with some previously reported values for phosphatidylcholines. Magnetic alignment will permit more sophisticated structural studies of monomeric and polymeric tubules, and provide a method of orienting macromolecules in the tubule walls or interior.

Rosenblatt, C; Yager, P; Schoen, P E

1987-01-01

100

Polar plumes' orientation and the Sun's global magnetic field  

NASA Astrophysics Data System (ADS)

Aims: We characterize the orientation of polar plumes as a tracer of the large-scale coronal magnetic field configuration. We monitor in particular the north and south magnetic pole locations and the magnetic opening during 2007-2008 and provide some understanding of the variations in these quantities. Methods: The polar plume orientation is determined by applying the Hough-wavelet transform to a series of EUV images and extracting the key Hough space parameters of the resulting maps. The same procedure is applied to the polar cap field inclination derived from extrapolating magnetograms generated by a surface flux transport model. Results: We observe that the position where the magnetic field is radial (the Sun's magnetic poles) reflects the global organization of magnetic field on the solar surface, and we suggest that this opens the possibility of both detecting flux emergence anywhere on the solar surface (including the far side) and better constraining the reorganization of the corona after flux emergence.

de Patoul, Judith; Inhester, Bernd; Cameron, Robert

2013-10-01

101

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.

Alerstam, T; Gudmundsson, GA

1999-01-01

102

Magnetic Field Orientation of Liquid Crystalline Epoxy Thermosets.  

PubMed

The effect of magnetic fields on the orientation and properties of 4,4'-bis(2,3-epoxypropoxy)-alpha-methylstilbene cured with sulfanilamide has been studied. This epoxy system is initially isotropic and forms a smectic A phase upon curing. A magnetic field was applied during the cure reaction, resulting in alignment of the molecules along the direction of the applied field. Measurement of the orientation parameter of the fully cured material by wide-angle X-ray scattering (WAXS) showed that orientation improved with an increase in field strength. The orientation parameters of the smectic layer normals calculated from the inner reflection of the WAXS pattern attained a maximum level of approximately 0.8 at a field strength of approximately 12 T. The orientation parameters calculated from the outer reflection of the WAXS pattern were considerably lower, possibly due to the presence of amorphous regions associated with domain boundaries or the loss of molecular alignment within the smectic layers due to topological restrictions of the cross-linking sites. Orientation resulted in an anisotropic linear thermal expansion coefficient after curing, although the overall volumetric expansion was constant. The elastic tensile modulus increased with the square of the orientation parameter, attaining a maximum value of 8.1 GPa, compared to 3.1 GPa for the unoriented material. The change in modulus with orientation could be fit with a simple model for the modulus of anisotropic materials. PMID:9680406

Benicewicz; Smith; Earls; Priester; Setz; Duran; Douglas

1998-07-28

103

Crystal orientation of non-magnetic materials by imposition of a high magnetic field  

Microsoft Academic Search

From the view point of learning from the nature, the controlling of crystal orientation is accounted to be a major subject for materials processing. This paper reviews the researches on the crystal orientation by use of a high magnetic field and belongs to the category of researches for mimicking structures, namely the crystal orientation, which nature or living bodies are

Shigeo Asai; Ken-suke Sassa; Masahiro Tahashi

2003-01-01

104

Magnetization analysis of oriented chains of hexagonal cobalt nanoplates  

NASA Astrophysics Data System (ADS)

High quality single-crystalline hexagonal cobalt nanoplates have been obtained by a simple chemical reduction method using ultrasonic assistance. Individual nanoplates tend to form agglomerates due to their strong in-plane anisotropy. These particles were incorporated within a polyethylene matrix by a solution blending method and arrays of magnetic chains were generated by solidification of the solution of nanoparticles in the presence of a magnetic field. The easy axis of the Co plates is oriented along the field, in the direction of the chains length. Micromagnetic simulations, magnetic measurements, and FORC diagrams are used to clarify the complex magnetic behavior in these systems.

Vargas, E.; Denardin, J. C.; Lavín, R.; Mascaró, P.; Chaneac, C.; Coradin, T.

2014-05-01

105

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

106

Diamagnetic orientation of blood cells in high magnetic field  

Microsoft Academic Search

Diamagnetic orientation of blood cells has been investigated in static high magnetic fields. The anisotropic diamagnetic susceptibility Deltachi of erythrocytes and blood platelets are determined. Deltachi of blood platelets is 1.5 times larger than that of erythrocytes. The contribution of microtubules to the Deltachi of platelets is also discussed.

A. Yamagashi; T. Takeuchi; T. Hagashi; M. Date

1992-01-01

107

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.

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

2009-01-01

108

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

109

COMPASS-II: COMPASS Future Programs  

SciTech Connect

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

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

2011-12-14

110

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.

111

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.

112

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

PubMed

External magnetic fields have been used to vertically align ensembles of silicon microwires coated with ferromagnetic nickel films. X-ray diffraction and image analysis techniques were used to quantify the degree of vertical orientation of the microwires. The degree of vertical alignment and the minimum field strength required for alignment were evaluated as a function of the wire length, coating thickness, magnetic history, and substrate surface properties. Nearly 100% of 100 ?m long, 2 ?m diameter, Si microwires that had been coated with 300 nm of Ni could be vertically aligned by a 300 G magnetic field. For wires ranging from 40 to 60 ?m in length, as the length of the wire increased, a higher degree of alignment was observed at lower field strengths, consistent with an increase in the available magnetic torque. Microwires that had been exposed to a magnetic sweep up to 300 G remained magnetized and, therefore, aligned more readily during subsequent magnetic field alignment sweeps. Alignment of the Ni-coated Si microwires occurred at lower field strengths on hydrophilic Si substrates than on hydrophobic Si substrates. The magnetic field alignment approach provides a pathway for the directed assembly of solution-grown semiconductor wires into vertical arrays, with potential applications in solar cells as well as in other electronic devices that utilize nano- and microscale components as active elements. PMID:23083440

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

2012-11-27

113

3Axis Magnetic Sensor Array System for Tracking Magnet's Position and Orientation  

Microsoft Academic Search

In medical diagnoses and treatments, e.g., the endoscopy, the dosage transition monitoring, it is often desirable to wirelessly track an object that moves through the human GI tract. In this paper, we present a magnetic localization and orientation system for such applications. This system uses a small magnet enclosed in the object to serve as excitation source. It does not

Chao Hu; Max Q.-H. Meng; Mrinal Mandal; Xiaona Wang

2006-01-01

114

About the orientation of the magnetization of the martian lithosphere.  

NASA Astrophysics Data System (ADS)

Using a previously described conjugate gradient technique to compute the magnetization of an equivalent source dipole mesh, we develop a new model of the Martian lithosphere magnetization using Mars Global Surveyor magnetic data acquired during the AeroBraking, Science Phase Orbit and Mapping Orbit phases of the mission. Our new model is compared to previously published ones in terms of fitting the observations. The major improvements with respect to the previous models comes from the use of the raw AB1/2 data instead of the AB-binned one. By comparing solutions derived on partial datasets we discuss about the orientation of the magnetization, which appears to be mostly vertical: assuming a pure vertical magnetization, predicted and observed field components are correlated up to 0.99, 0.98 and 0.96 for Br, B? and B? , respectively. Using our magnetization model we compute altitude-normalized maps for altitudes ranging between 200 and 400 km. The magnetic field is compared to other physical properties, such as the crater density, the gravity and the topography.

Langlais, B.; Purucker, M.; Mandea, M.

2002-05-01

115

ACQUISITION OF MAGNETIC DIRECTIONAL PREFERENCE IN HATCHLING LOGGERHEAD SEA TURTLES  

Microsoft Academic Search

Summary During their natal migration, hatchling loggerhead sea turtles ( Caretta caretta L.) establish courses towards the open ocean and maintain them after swimming beyond sight of land. Laboratory experiments have demonstrated that swimming hatchlings can orient using the earth's magnetic field. For the magnetic compass to function in guiding the offshore migration, however, hatchlings must inherit or acquire a

KENNETH J. LOHMANN; CATHERINE M. FITTINGHOFF LOHMANN

1994-01-01

116

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

117

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.

118

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

NASA Astrophysics Data System (ADS)

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

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

2011-08-01

119

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

120

Electromagnetic imaging with an arbitrarily oriented magnetic dipole  

NASA Astrophysics Data System (ADS)

We present the theoretical background for the geophysical EM analysis with arbitrarily oriented magnetic dipoles. The first application of such a development is that we would now be able to correct the data when they are not acquired in accordance to the actual interpretation methods. In order to illustrate this case, we study the case of airborne TEM measurements over an inclined ground. This context can be encountered if the measurements are made in mountain area. We show in particular that transient central loop helicopter borne magnetic data should be corrected by a factor proportional to the angle of the slope under the system. In addition, we studied the sensitivity function of a grounded multi-angle frequency domain system. Our development leads to a general Jacobian kernel that could be used for all the induction number and all the position/orientation of both transmitter and receiver in the air layer. Indeed, if one could design a system controlling the angles of Tx and Rx, the present development would allow to interpret such a data set and enhance the ground analysis, especially in order to constrain the 3D anisotropic inverse problem.

Guillemoteau, Julien; Sailhac, Pascal; Behaegel, Mickael

2013-04-01

121

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

122

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

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

1990-01-01

123

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

124

The Compass Project  

NSDL National Science Digital Library

In this presentation, members of the Compass Project discuss ways to support underrepresented undergraduates in physics, especially at the critical freshman transition. The data presented is in the context of The Compass Project, a program created at the University of California, Berkeley in 2006. Drawing on physics education research, the project had two major goals in creating a two-week summer program for incoming freshman: building community and helping students develop productive beliefs about what physics is and how to learn it. Recently, an innovative semester-long course on physics problem-solving was developed to help the Compass students develop their critical thinking skills (and continue to build community) throughout the academic year. Starting with a first seed group of eleven students, the project members have mentored and encouraged undergraduates as they continue to make a positive impact on the Berkeley physical science departments by bringing other students into the Compass community, volunteering at inner-city schools, and even running a lecture series aimed at an undergraduate audience.

Little, Angela; Haggard, Hal; Hernandez, Felicitas; Corbo, Joel C.

2010-02-24

125

Future plans at COMPASS  

Microsoft Academic Search

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

J. Pretz

2010-01-01

126

Compassion: Practical Classroom Activities  

ERIC Educational Resources Information Center

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

Wong, Lily; Duffy, Roslyn Ann

2010-01-01

127

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...

2009-07-20

128

Compass-Ii  

NASA Astrophysics Data System (ADS)

On December 1st 2010 the proposal of the COMPASS-II Experiment [1] has been approved by the CERN Research Board. After almost ten years of important results achieved by the COMPASS Collaboration in both nucleon spin physics, with the use of muon beam, and hadron spectroscopy, using hadron beams, this second phase offers now a unique chance to address in the very near future newly opened QCD-related challenges, at very moderate upgrade cost, thanks to the versatility of the COMPASS apparatus [2]. This implies mainly study of chiral perturbation theory (ChPT), by measuring the pion polarizability through Primakoff reaction; generalized parton distributions (GPDs), by measuring exclusive deeply virtual compton scattering (DVCS) and hard exclusive meson production (DVMP); transverse momentum dependent parton distributions (TMDs) in single-polarised pion-induced Drell-Yan muon production and in SIDIS on a liquid hydrogen target (in parallel to DVCS). An overview of the COMPASS-II proposal is presented here, with a main focus on the new upcoming investigation of the nucleon structure via the Drell-Yan and DVCS processes.

Chiosso, M.

2013-11-01

129

Meson Spectroscopy at COMPASS  

Microsoft Academic Search

QCD predicts four quark states or gluonic excitations like hybrids or glueballs to contribute to the meson spectrum in addition to qq pair configurations. The most promising way to identify such states is the search for JPC quantum number combinations which are forbidden in the constituent quark model. The fixed target COMPASS experiment at CERN offers the opportunity to search

Florian HAAS

2009-01-01

130

Chaos and Compassion.  

ERIC Educational Resources Information Center

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

Gelatt, H. B.

1995-01-01

131

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

132

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

PubMed Central

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.

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

2012-01-01

133

Iron-mineral-based magnetoreceptor in birds: polarity or inclination compass?  

Microsoft Academic Search

In the present paper we demonstrate that the iron-mineral-based magnetoreceptor model developed in [1] can provide birds with\\u000a a magnetic compass in addition to the generally believed “magnetic map\\

I. A. Solov’yov; W. Greiner

2009-01-01

134

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 therefore the compass will respond 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.

Vu Bioengineering Ret Program

135

Compact Airborne Spectral Sensor (COMPASS)  

NASA Astrophysics Data System (ADS)

The COMPACT Airborne Spectral Sensor (COMPASS) design is intended to demonstrate a new design concept for solar reflective hyper spectral systems for the Government. Capitalizing from recent focal plane developments, the COMPASS system utilizes a single FPA to cover the 0.4-2.35micrometers spectral region. This system also utilizes an Offner spectrometer design as well as an electron etched lithography curved grating technology pioneered by NASA/JPL. This paper also discusses the technical trades, which drove the design selection of COMPASS. When completed, the core COMPASS spectrometer design could be used in a large variety of configurations on a variety of aircraft.

Simi, Christopher G.; Winter, Edwin M.; Williams, Mary M.; Driscoll, David C.

2001-08-01

136

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.

Minnesota, Science M.

2011-10-31

137

Quantum Control and Entanglement in a Chemical Compass  

Microsoft Academic Search

The radical-pair mechanism is one of the two main hypotheses to explain the navigability of animals in weak magnetic fields, enabling, e.g., birds to see Earth's magnetic field. It also plays an essential role in spin chemistry. Here, we show how quantum control can be used to either enhance or reduce the performance of such a chemical compass, providing a

Jianming Cai; Gian Giacomo Guerreschi; Hans J. Briegel

2010-01-01

138

Quantum Control and Entanglement in a Chemical Compass  

Microsoft Academic Search

The radical-pair mechanism is one of the two main hypotheses to explain the navigability of animals in weak magnetic fields, enabling, e.g., birds to see Earth's magnetic field. It also plays an essential role in spin chemistry. Here, we show how quantum control can be used to either enhance or reduce the performance of such a chemical compass, providing a

Gian Giacomo Guerreschi; Jianming Cai; Hans J. Briegel

2011-01-01

139

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

140

Analysis and microprocessor implementation of field oriented control for permanent magnet hysteresis synchronous motor  

Microsoft Academic Search

An analytical motor for a permanent magnet hysteresis hybrid synchronous motor has been developed. A microprocessor-based field oriented control scheme has been successfully experimented for a laboratory magnet hysteresis motor. A scheme for measuring the torque angle is proposed. The test results confirm the improvement of the dynamic performances using a field-oriented control strategy

J. Qian; M. Azizur Rahman

1991-01-01

141

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 (MR/MS? 1), suggesting cubic anisotropy in the system, whereas for the NP sample, typical features of uniaxial anisotropy (MR/MS? 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 (KE) of the system. A high-temperature enhancement of HC and KE 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

142

Mag Lab U: Interactive Tutorials - Oersted's Compass  

NSDL National Science Digital Library

This interactive tutorial simulates the simple, yet groundbreaking, 1820 experiment that paved the way for understanding the relationship between electricity and magnetism. It is a virtual version of Hans Christian Oersted's voltaic pile battery outfitted with a live electrical wire. Students can turn the current on/off and also flip the battery. Watch what happens to the nearby compass to see why this experiment rocked the scientific world of the early 1800's. Mag Lab U is part of a large collection of web-based educational materials for K-20, developed by the National High Magnetic Field Laboratory at Florida State University.

2011-01-23

143

Probing dynamical magnetization pinning in circular dots as a function of the external magnetic field orientation  

NASA Astrophysics Data System (ADS)

We performed ferromagnetic resonance measurements of square arrays of noninteracting Permalloy circular dots for different orientations of external magnetic field with respect to the patterned film plane (?). Out-of-plane angular dependence of the main resonance peak was measured in the whole range of the field angles 0° ? ? ? 90°. The main eigenmodespatial distribution is strongly nonuniform due to the dot nonellipsoidal shape. Nevertheless, for dots with small aspect ratio b=L/R?0.1 (where R is dot radius and L is dot thickness) Kittel's equation, assuming uniform dynamic magnetization (no pinning at the dot lateral edges), describes the peak position with high accuracy. Analytical calculations and micromagnetic simulations confirmed the gradual evolution of the main mode profile and a smooth transition from the strong to relatively weak pinning conditions with the change of external magnetic field angle.

Kakazei, G. N.; Aranda, G. R.; Bunyaev, S. A.; Golub, V. O.; Tartakovskaya, E. V.; Chumak, A. V.; Serga, A. A.; Hillebrands, B.; Guslienko, K. Y.

2012-08-01

144

Iron-mineral-based magnetoreceptor in birds: polarity or inclination compass?  

NASA Astrophysics Data System (ADS)

In the present paper we demonstrate that the iron-mineral-based magnetoreceptor model developed in [1] can provide birds with a magnetic compass in addition to the generally believed “magnetic map". We show that the iron-mineral-based magnetoreceptor system possesses all properties of a polarity compass, which is extremely important for avian navigation. We study how parameters of the magnetoreceptor system influence on the properties of the compass and show that at certain conditions it acquires features of an inclination compass. In the present paper we address the question of avian magnetoreception theoretically and suggest several experiments which should be performed for better understanding of the iron-mineral-based compass in birds.

Solov'yov, I. A.; Greiner, W.

2009-01-01

145

Is the Quantum Zeno Effect Evolution's Choice for the Avian Compass?  

Microsoft Academic Search

Magnetic-sensitive radical-ion-pair reactions are understood to underlie the biochemical magnetic compass used by avian species for navigation. Radical-ion-pair reactions were recently shown to manifest a host of quantum-information-science effects, like quantum jumps and the quantum Zeno effect. We here show that the quantum Zeno effect immunizes the magnetic and angular sensitivity of the avian compass mechanism against the deleterious and

I. K. Kominis

2009-01-01

146

Compact Digital Compass with PCB Fluxgate Sensors  

Microsoft Academic Search

The new compact digital compass with PCB fluxgate sensors and accelerometers will be introduced in this contribution. Competitive low-cost, low-accuracy compasses are dedicated for measurement in horizontal plane only. The main advantage of developed compass is that it is able to determine azimuth in every position. The compass module consists of a tri axial fluxgate magnetometer and tri axial MEMS

J. Vcelak; V. Petrucha; P. Kaspar

2006-01-01

147

Future plans at COMPASS  

NASA Astrophysics Data System (ADS)

After successfully running since several years with polarized muon and hadron beams to study the spin structure of the nucleon and spectroscopy of hadrons, the COMPASS (Common Muon and Proton Apparatus for Structure and Spectroscopy) experiment enters a second phase with a new extended physics program to obtain deeper insight in the partonic structure of matter. These future plans include a measurement of deep virtual Compton scattering in order to determine generalized parton distributions and the study of the polarized DrellYan process giving access to transverse momentum dependent (TMD) parton distributions. Recent results and these future plans will be presented in this document.

Pretz, J.

2010-04-01

148

Gpd Program at Compass  

NASA Astrophysics Data System (ADS)

The study of exclusive reactions like Deeply Virtual Compton Scattering (DVCS) and Meson Production is one major part of the future COMPASS program in order to investigate nucleon structure through Generalised Parton Distributions (GPD). The high energy of the muon beam allows to measure the xB-dependence of the t-slope of the pure DVCS cross section and to study nucleon tomography. The use of positive and negative polarised muon beams allows to determine the Beam Charge and Spin Difference of the DVCS cross sections to access the real part of the Compton form factor related to the dominant GPD H.

D'Hose, N.

2011-02-01

149

Control of the orientation of human erythrocytes by magnetic and electric fields  

NASA Astrophysics Data System (ADS)

The orientation of human red blood cells (RBCs) was controlled by the application of magnetic and electric fields. Because of their anisotropic diamagnetism, RBCs orient parallel to strong magnetic fields. The electric orientation of erythrocytes is also caused by electric dipoles induced by an electric field. The RBCs orientation is parallel to both the electric and magnetic fields. A 4-5 kV/m alternating current (ac) electric field (10-200 kHz, sine wave) was applied to RBCs suspended in a phosphate buffer solution using a pair of platinum black electrodes spaced 200-250 ?m apart. An 8 T magnetic field was applied to the RBCs perpendicular to the direction of the electric field. It was observed that all RBCs were oriented in the same direction and parallel to the electric and magnetic fields. By the application of a horizontal 8 T magnetic field and a 4 kV/m ac electric field positioned perpendicular to one another, the RBCs oriented horizontally and their sedimentation rate was decreased by 18%. The flowing rate of the 10% RBCs suspension was decreased by 7.6% with the application of an 8 T magnetic field and a 4 kV/m ac electric field perpendicular to the direction of the suspension flow. It was observed that flowing RBCs were oriented perpendicular to the direction of the flow by the application of the fields, when the velocity of the suspension of RBCs was less than 300 ?m/s.

Suda, T.; Ueno, S.

1999-04-01

150

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

151

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.

2012-02-01

152

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

PubMed Central

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

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

1995-01-01

153

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.

Holland, Richard A.

2010-01-01

154

31P NMR first spectral moment study of the partial magnetic orientation of phospholipid membranes.  

PubMed Central

Structural data can be obtained on proteins inserted in magnetically oriented phospholipid membranes such as bicelles, which are most often made of a mixture of long and short chain phosphatidylcholine. Possible shapes for these magnetically oriented membranes have been postulated in the literature, such as discoidal structures with a thickness of one bilayer and with the short acyl chain phosphatidylcholine on the edges. In the present paper, a geometrical study of these oriented structures is done to determine the validity of this model. The method used is based on the determination of the first spectral moment of solid-state (31)P nuclear magnetic resonance spectra. From this first moment, an order parameter is defined that allows a quantitative analysis of partially oriented spectra. The validity of this method is demonstrated in the present study for oriented samples made of DMPC, DMPC:DHPC, DMPC:DHPC:gramicidin A and adriamycin:cardiolipin.

Picard, F; Paquet, M J; Levesque, J; Belanger, A; Auger, M

1999-01-01

155

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

SciTech Connect

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

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

1996-02-01

156

Analysis of field oriented control for permanent magnet hysteresis synchronous motors  

Microsoft Academic Search

Field oriented control schemes provide significant improvement to the dynamic performance of ac motors. A microprocessor implementation of the field oriented control scheme for the permanent magnet hysteresis synchronous motor has been reported for the first time. The basic principle is to decouple the torque-current component from the flux-current component so that these two components can be independently controlled. A

J. Qian; M. A. Rahman

2009-01-01

157

Ordering and Phase Transition of the Potts Compass Model  

NASA Astrophysics Data System (ADS)

In the Mott insulating phase of the transition metal oxides, the effective orbital-orbital interaction is directional both in the orbital space and in the real space. A model with directional dependent coupling is the Compass Model, given by H=sum_i(S_i^xS_i+x^x+S_i^yS_i+y^y), where S is the iso-spin operator. Due to the entropy gap, four orientations S are favoured. By restricting to these orientations, the Compass Model is approximated by a Potts version, H=sum_i(?_i?_i+x+?_i?_i+y) where, ?_i=±1, ?_i=0 or, ?_i=±1, ?_i=0,. In the thermodynamics limit, the Potts Compass Model (PCM) is mapped exactly into the 2D Ising model (2DIM). Using this mapping, we show rigorously that there is no conventional orbital order at finite T, but there is LRO in orbital fluctuations. Tc is solved exactly to be 0.42J. For finite size, the PCM differs from the 2DIM. We study the finite-size crossover using numerical simulations and real space RG calculations of the PCM. Numerical simulations on the original Compass Model shows that it has a lower Tc due to slow fluctuations absent in the PCM.

Mishra, Anup; Ma, Michael; Zhang, Fu-Chun; Tang, Lei-Han; Guertler, Siegfried

2004-03-01

158

GEM Detectors for Compass  

NASA Astrophysics Data System (ADS)

For the small-area tracking of the COMPASS experiment, GEM detectors with an active area of 31 × 31 cm2 are employed. These detectors use three cascaded GEM foils with asymmetric voltage sharing and Ar:CO2 (70/30) as detector gas. The GEMs have a non-uniformity in gain of less than ±15% and achieve an efficiency of 99.0 ± 0.1% and a spatial resolution of 46 ± 3 ?m for minimum-ionizing particles at nominal gain of ~ 8000. The narrow charge correlation (?rat< 0.1) between the orthogonal coordinates of the 2D projective readout improves the reconstruction capability for multiple hits. High rate tolerance and low discharge probability make the GEM detectors well suited for operation in intense muon and hadron beams.

Simon, Frank; Friedrich, Jan; Grube, Boris; Konorov, Igor; Paul, Stephan; Altunbas, Cem; Kappler, Steffen; Ketzer, Bernhard; Placci, Alfredo; Ropelewski, Leszek; Sauli, Fabio

2002-11-01

159

Hybrid Meson Structure at COMPASS  

Microsoft Academic Search

We describe a pion physics program attainable with the CERN COMPASS spectrometer, involving tracking detectors and an electromagnetic calorimeter. COMPASS can realize state-of-the-art pion beam hybrid meson and meson radiative transition studies. We review here the physics motivation for this program. We describe the beam, detector, trigger requirements, and hardware\\/software requirements for this program. The triggers for all this hybrid

Murray Moinester; Suh Urk Chung

2000-01-01

160

Magnetic-Crystallographic Orientation Produced in Ferrites by Hot Working.  

National Technical Information Service (NTIS)

Hot forging of barium cobalt ferrite and barium ferrite gives rise to orientation of the crystallites in a polycrystalline body, with the basal planes of the hexagonal unit cells are aligned perpendicular to the forging direction. Microstructurally the bo...

R. M. Haag

1969-01-01

161

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.

Vu Bioengineering Ret Program

162

Orientation of aurora and the concurrent magnetic disturbance  

Microsoft Academic Search

Orientations of auroral arcs have been determined from all-sky photographs taken at Flin Flon (54.8°N, 101.8°W), Canada during 1958. The corresponding magnetograms were also examined in an attempt to verify the theory that intense ionospheric currents flow along the auroral arc during the auroral display. The average value for the orientation of auroral arcs was found to be 98.4°. Significant

J. S. Kim; C. S. Wang

1967-01-01

163

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.

Kansas, University O.

2006-01-01

164

Using an electronic compass to determine telemetry azimuths  

USGS Publications Warehouse

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

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

2002-01-01

165

Orientation-controlled synthesis and magnetism of single crystalline Co nanowires  

NASA Astrophysics Data System (ADS)

Orientation control and the magnetic properties of single crystalline Co nanowires fabricated by electrodeposition have been systematically investigated. It is found that the orientation of Co nanowires can be effectively controlled by varying either the current density or the pore diameter of AAO templates. Lower current density or small diameter is favorable for forming the (1 0 0) texture, while higher current values or larger diameter leads to the emergence and enhancement of (1 1 0) texture of Co nanowires. The mechanism for the manipulated growth characterization is discussed in detail. The orientation of Co nanowires has a significant influence on the magnetic properties, resulting from the competition between the magneto-crystalline and shape anisotropy of Co nanowires. This work offers a simple method to manipulate the orientation and magnetic properties of nanowires for future applications.

Huang, Gui-Fang; Huang, Wei-Qing; Wang, Ling-Ling; Zou, B. S.; Pan, Anlian

2012-11-01

166

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

167

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."

Nasa

2012-06-26

168

Influence of the agglomeration in the initial suspension (ferrofluid) on the oriented magnetic structure  

NASA Astrophysics Data System (ADS)

The process was studied of preparation of oriented BaFe12O19 films via deposition of BaFe12O19 nanoparticles from a suspension in a magnetic field. The films' structural, microstructural and magnetic properties were investigated by X-ray diffraction, scanning electron microscopy and magnetic measurements. The influence was explored of the particles's agglomeration in the ferrofluid on the films' properties and microstructure. Using time delay deposition, we obtained thick films with a high degree of orientation and good density.

Kolev, S.; Koutzarova, T.

2014-05-01

169

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.

2011-01-01

170

The Geoeffectiveness of Magnetic Clouds as a Function of Their Orientation  

NASA Astrophysics Data System (ADS)

Trying to get light into the paradigm of forecasting geomagnetic activity, we have looked for a relationship between geoeffectiveness and the orientation and helicity of magnetic clouds. During the years 1995-2000, we have selected all the geomagnetic storms with Dst index less than -70 nT. Then, we have inspected WIND data looking for a possible magnetic cloud related to every storm event. When a magnetic cloud is encountered, we have fitted to experimental data a model that we have developed for the magnetic cloud topology in order to obtain the attitude of the magnetic cloud and its helicity. On the basis of the results obtained, a close relationship is observed between the orientation of the magnetic cloud and its helicity, and the geomagnetic activity.

Cid, C.; Nieves-Chinchilla, T.; Hidalgo, M. A.; Sáiz, E.; Cerrato, Y.

2003-09-01

171

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.

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

2005-01-01

172

Magnetic-field-induced orientational phase structure transition.  

PubMed

Magnetic field effect on the phase transition at high temperature (from 50 °C) inside the magnetic field has been found in C14G2 (N-tetradecyllactobionamide)/C12EO4 (tetraethylene glycol monododecyl ether)/D2O system. The phase was transited quickly from lamellar phase to isotropic phases [bottom, micellar phase (L1 phase) and top, sponge phase (L3 phase)] induced by a magnetic field, which was demonstrated by (2)H NMR and FF-TEM measurements. The isotropic phases induced by magnetic field were not stable, and the upper L3 phase can recover to lamellar phase after being restored in a 55 °C thermostat outside the magnetic field for about one month. During the mechanism study, the C12EO4 molecule was proved to be the dominant component for the phase transition induced by the magnetic field, while the C14G2 molecule was the auxiliary and just affected the transition speed. The breaking and rebuilding of hydrogen bonds could play an important role in the phase transition and recovering. Moreover, the surfactant concentration had an effect on the speed of phase transiting and phase recovering. These observations could provide an understanding of the phase transition and also the applications for the controlled drug delivery system of bilayer membranes driving, induced by the magnetic field. PMID:24447257

Dou, Yingying; Dong, Shuli; Hao, Jingcheng

2014-02-11

173

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

174

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

PubMed

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

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

2014-05-27

175

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

176

Compassion: An Evolutionary Analysis and Empirical Review  

Microsoft Academic Search

What is compassion? And how did it evolve? In this review, we integrate 3 evolutionary arguments that converge on the hypothesis that compassion evolved as a distinct affective experience whose primary function is to facilitate cooperation and protection of the weak and those who suffer. Our empirical review reveals compassion to have distinct appraisal processes attuned to undeserved suffering; distinct

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

2010-01-01

177

Magnetic information affects the stellar orientation of young bird migrants  

NASA Astrophysics Data System (ADS)

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

Weindler, Peter; Wiltschko, Roswitha; Wiltschko, Wolfgang

1996-09-01

178

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

SciTech Connect

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

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

1996-03-01

179

Quantum control and entanglement in a chemical compass.  

PubMed

The radical-pair mechanism is one of the two main hypotheses to explain the navigability of animals in weak magnetic fields, enabling, e.g., birds to see Earth's magnetic field. It also plays an essential role in spin chemistry. Here, we show how quantum control can be used to either enhance or reduce the performance of such a chemical compass, providing a new route to further study the radical-pair mechanism and its applications. We study the role of radical-pair entanglement in this mechanism, and demonstrate its intriguing connections with the magnetic-field sensitivity of the compass. Beyond their immediate application to the radical-pair mechanism, these results also demonstrate how state-of-the-art quantum technologies could potentially be used to probe and control biological functions. PMID:20867156

Cai, Jianming; Guerreschi, Gian Giacomo; Briegel, Hans J

2010-06-01

180

Quantum Control and Entanglement in a Chemical Compass  

NASA Astrophysics Data System (ADS)

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

Cai, Jianming; Guerreschi, Gian Giacomo; Briegel, Hans J.

2010-06-01

181

Quantum Control and Entanglement in a Chemical Compass  

NASA Astrophysics Data System (ADS)

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

Giacomo Guerreschi, Gian; Cai, Jianming; Briegel, Hans J.

2011-03-01

182

Analysis of field oriented control for permanent magnet hysteresis synchronous motors  

Microsoft Academic Search

A microprocessor implementation of the field-oriented control scheme for the permanent magnet (PM) hysteresis synchronous motor is reported. The basic principle is to decouple the torque-current component from the flux-current component so that these two components can be independently controlled. A d-q axis model of the PM hysteresis synchronous motor is presented, and the field-oriented control obtained from the basic

Jianhua Qian; M. Azizur Rahman

1993-01-01

183

When a crack is oriented by a magnetic field.  

PubMed

Upon drying, colloidal suspensions undergo a phase transformation from a "liquid" to a "gel" state. With further solvent evaporation, tensile stresses develop in the gel, which ultimately leads to fractures. These generally manifest themselves in regular cracking patterns which reflect the physical conditions of the drying process. Here we show experimentally and theoretically how, in the case of a drying droplet of magnetic colloid (ferrofluid), an externally applied magnetic field modifies the stress in the gel and therefore the crack patterns. We find that the analysis of the shape of the cracks allows one to estimate the value of the gel Young's modulus just before the crack nucleation. PMID:18352026

Pauchard, L; Elias, F; Boltenhagen, P; Cebers, A; Bacri, J C

2008-02-01

184

When a crack is oriented by a magnetic field  

NASA Astrophysics Data System (ADS)

Upon drying, colloidal suspensions undergo a phase transformation from a “liquid” to a “gel” state. With further solvent evaporation, tensile stresses develop in the gel, which ultimately leads to fractures. These generally manifest themselves in regular cracking patterns which reflect the physical conditions of the drying process. Here we show experimentally and theoretically how, in the case of a drying droplet of magnetic colloid (ferrofluid), an externally applied magnetic field modifies the stress in the gel and therefore the crack patterns. We find that the analysis of the shape of the cracks allows one to estimate the value of the gel Young’s modulus just before the crack nucleation.

Pauchard, L.; Elias, F.; Boltenhagen, P.; Cebers, A.; Bacri, J. C.

2008-02-01

185

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

186

Diamagnetic Orientation of Polymerized Molecules under High Magnetic Field  

Microsoft Academic Search

Diamagnetic alignment of polymerized organic molecules is discussed both from the theoretical and experimental points of view. When a number of molecules aggregate with their diamagnetic principal axes along the same direction, the resultant diamagnetic anisotropy energy becomes comparable to the thermal energy and the aggregated molecule can align under a conventional magnetic field, even at room temperatures. Polymerization of

Akio Yamagishi; Tetsuya Takeuchi; Terumasa Higashi; Muneyuki Date

1989-01-01

187

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

SciTech Connect

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

Birsan, M.; Szpunar, J.A. [McGill Univ., Montreal, Quebec (Canada). Dept. of Metallurgical Engineering] [McGill Univ., Montreal, Quebec (Canada). Dept. of Metallurgical Engineering; Krause, T.W.; Atherton, D.L. [Queen`s Univ., Kingston, Ontario (Canada). Dept. of Physics] [Queen`s Univ., Kingston, Ontario (Canada). Dept. of Physics

1996-03-01

188

A vector oriented control for a magnetically levitated shaft  

SciTech Connect

Considering the nonlinear model of Active Magnetic Bearings, a new means of nonlinear control is presented which treats variables as rotating vectors in the control plane, specially the unbalance. It became easy to cancel out the effect of this perturbation in a rotating reference. Therefore, the rotor can rotate around any desired point, particularly the geometric center or the center of gravity. Simulations illustrate the efficacy of this control law.

De Miras, J.; Charara, A. [UTC, Compiegne (France)] [UTC, Compiegne (France)

1998-07-01

189

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

190

Anisotropy-axis orientation effect on the magnetization of ?-Fe2O3 frozen ferrofluid  

NASA Astrophysics Data System (ADS)

The effect of magnetic anisotropy-axis alignment on the superparamagnetic (SPM) and superspin glass (SSG) states in a frozen ferrofluid has been investigated. The ferrofluid studied here consists of maghemite nanoparticles (?-Fe2O3, mean diameter = 8.6 nm) dispersed in glycerine at a volume fraction of ~15%. In the high temperature SPM state, the magnetization of aligned ferrofluid increased by a factor varying between 2 and 4 with respect to that in the randomly oriented state. The negative interaction energy obtained from the Curie-Weiss fit to the high temperature susceptibility in the SPM states as well as the SSG phase onset temperature determined from the linear magnetization curves were found to be rather insensitive to the anisotropy-axis alignment. The low temperature ageing behaviour, explored via 'zero-field cooled magnetization' relaxation measurements, however, shows a distinct difference in the ageing dynamics in the anisotropy-axis aligned and randomly oriented SSG states.

Nakamae, S.; Crauste-Thibierge, C.; Komatsu, K.; L'Hôte, D.; Vincent, E.; Dubois, E.; Dupuis, V.; Perzynski, R.

2010-12-01

191

Elementary Map and Compass Instruction.  

ERIC Educational Resources Information Center

The purpose of this booklet is to help teachers, scoutmasters, and other group leaders give elementary map and compass instructions in a manner that is both simple and fun. It is intended to be a guide for a training course on this subject. Much of the text is taken directly from an actual training course and is written in the manner of a teacher…

Larson, Elston F.

192

Highlights from the COMPASS experiment  

Microsoft Academic Search

The Compass experiment at CERN is studying the nucleon spin structure with a 160 GeV polarized muon beam and polarized targets as well as hadron structure with 190 GeV pion, kaon and proton beams. The paper gives an overview of the results for the helicity and transverse spin structure of the nucleon. A first result from the spectroscopy experiments, the

G. K. Mallot

2010-01-01

193

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

194

Fully deuterated magnetically oriented system based on Fatty Acid direct hexagonal phases.  

PubMed

There is strong demand in the field of NMR for simple oriented lipid supramolecular assemblies, the constituents of which can be fully deuterated, for specifically studying the structure of host protonated molecules (e.g., peptides, proteins...) in a lipid environment. Also, small-angle neutron scattering (SANS) in fully deuterated oriented systems is powerful for gaining information on protonated host molecules in a lipid environment by using the contrast proton/deuterium method. Here we report on a very simple system made of fatty acids (dodecanoic and tetradecanoic) and ethanolamine in water. All components of this system can be obtained commercially as perdeuterated. Depending on the molar ratio and the concentration, the system self-assembles at room temperature into a direct hexagonal phase that is oriented by moderate magnetic fields of a few tesla. The orientation occurs within the magnetic field upon cooling the system from its higher-temperature isotropic phase: the lipid cylinders of the hexagonal phase become oriented parallel to the field. This is shown by solid-state NMR using either perdeuterated fatty acids or ethanolamine. This system bears strong interest for studying host protonated molecules but also in materials chemistry for building oriented solid materials. PMID:24758608

Douliez, Jean-Paul; Navailles, Laurence; Dufourc, Erick J; Nallet, Frédéric

2014-05-13

195

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

Microsoft Academic Search

Rotational magnetization of grain oriented SiFe sheets involves three mechanisms: anisotropy, hysteresis and eddy currents. Apart from describing the respective physical background, the paper is focused on a separation of mechanisms. It discusses dependencies between field quantities which in the dynamic case are complicated by the fact that a three-dimensional field problem arises here. It is demonstrated that within a

H. Pfiitzner

1994-01-01

196

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

197

A quantum mechanical approach to establishing the magnetic field orientation from a maser Zeeman profile  

NASA Astrophysics Data System (ADS)

Recent comparisons of magnetic field directions derived from maser Zeeman splitting with those derived from continuum source rotation measures have prompted new analysis of the propagation of the Zeeman split components, and the inferred field orientation. In order to do this, we first review differing electric field polarization conventions used in past studies. With these clearly and consistently defined, we then show that for a given Zeeman splitting spectrum, the magnetic field direction is fully determined and predictable on theoretical grounds: when a magnetic field is oriented away from the observer, the left-hand circular polarization is observed at higher frequency and the right-hand polarization at lower frequency. This is consistent with classical Lorentzian derivations. The consequent interpretation of recent measurements then raises the possibility of a reversal between the large-scale field (traced by rotation measures) and the small-scale field (traced by maser Zeeman splitting).

Green, J. A.; Gray, M. D.; Robishaw, T.; Caswell, J. L.; McClure-Griffiths, N. M.

2014-06-01

198

Enhancement of microwave emission in magnetic tunnel junction oscillators through in-plane field orientation  

NASA Astrophysics Data System (ADS)

We observe giant enhancement of microwave emission in MgO-based magnetic tunnel junction nano-oscillators through in-plane magnetic field orientation. At an optimal in-plane field angle, the output power reaches up to 240 nW, two orders of magnitude higher compared to the vicinity of the easy axis (~1 nW). Moreover, in this condition, the linewidth is significantly narrowed (<100 MHz) and the additional precession modes are suppressed. Analysis of the data indicates that the optimal field angle is influenced by the field-like torque. The results demonstrate that controlling the in-plane magnetic field orientation can be an important strategy for developing high-power spin-torque oscillators.

Zeng, Z. M.; Upadhyaya, P.; Khalili Amiri, P.; Cheung, K. H.; Katine, J. A.; Langer, J.; Wang, K. L.; Jiang, H. W.

2011-07-01

199

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

PubMed Central

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

2010-01-01

200

Is the Quantum Zeno Effect Evolution's Choice for the Avian Compass?  

Microsoft Academic Search

Magnetic-sensitive radical-ion-pair reactions are understood to underlie the\\u000abiochemical magnetic compass used by avian species for navigation.\\u000aRadical-ion-pair reactions were recently shown to manifest a host of\\u000aquantum-information-science effects, like quantum jumps and the quantum Zeno\\u000aeffect. We here show that the quantum Zeno effect immunizes the magnetic and\\u000aangular sensitivity of the avian compass mechanism against the deleterious and

I. K. Kominis

2009-01-01

201

Is compassion essential to nursing practice?  

PubMed

The Norwegian Nurses' Association recently (2001) approved a new code of ethics that included compassion as one of the basic values in nursing care. This paper examines the idea of compassion in the context of the Bible story of the Good Samaritan using an analysis of qualitative data from nurses' clinical work with psychiatric patients. The aim is to show how the idea of compassion challenges nursing practice. Thereafter, the paper discusses the benefits of and premises for compassion in care work. The results show that nurses tend not to be guided by compassion in their work with patients. The organisation of the day-to-day work in the hospital ward, the division of labour between nurses and doctors, and the nurses' approach to nursing were identified as influencing this tendency. The study shows that compassion is a radical concept with a potential to promote greater respect for patients' dignity. PMID:17929733

Hem, Marit Helene; Heggen, Kristin

2004-01-01

202

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

203

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

NASA Astrophysics Data System (ADS)

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

Gürsoy, D.; Scharfetter, H.

2009-10-01

204

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

PubMed Central

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

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

2008-01-01

205

Measuring compassion in physician assistants.  

PubMed

While compassion is generally agreed to be one of the professional qualities required of physician assistants (PAs), the concept has been remarkably difficult to define and measure. The authors describe a series of studies that generated preliminary information about the compassionate qualities of PAs. In an initial survey, PAs rated their own compassionate qualities, after which their patients assessed the same qualities in them. The patients validated three elements of compassion having to do with communication between PA and patient but failed to validate seven other items. Subsequent research dealt with a halo effect related to the wording of the questions and a confounding effect associated with the intimacy of the medical setting. PMID:12635436

Skaff, Karen O; Toumey, Christopher P; Rapp, Doris; Fahringer, David

2003-01-01

206

A new stator-flux orientation strategy for flux-switching permanent magnet motor based on current-hysteresis control  

Microsoft Academic Search

A stator-flux orientation strategy based on current hysteresis for the flux-switching permanent magnet (FSPM) motor is proposed, in which the stator-PM FSPM motor is considered as a conventional rotor-PM surface-mounted motor and an equivalent rotor-orientated dq-axes synchronous reference frame is built although there are actually no rotary magnetic motive force produced by the stator magnets in the FSPM motor. Based

Wei Hua; Ming Cheng; Wei Lu; Hongyun Jia

2009-01-01

207

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

PubMed Central

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

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

2013-01-01

208

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

209

Low temperature nuclear orientation studies of the magnetic structures of RNiAl4 in applied magnetic fields  

NASA Astrophysics Data System (ADS)

Low temperature nuclear orientation (LTNO) is applied to thermal neutron irradiated single crystal (160Tb)TbNiAl4. The magnetic field dependence of the gamma ray anisotropy is recorded and a temporary reduction is seen only during the transit of the first TbNiAl4 metamagnetic transition at ˜7 T, indicating the changed magnetic structure of the higher field phase still has essentially a axis moment alignment. A similar behaviour is seen for (147Nd)NdNiAl4.

Hutchison, W. D.; Alexander, L. K.; Nishimura, K.

2010-04-01

210

Penetrant-Indication-Measuring Compass  

NASA Technical Reports Server (NTRS)

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

Schaefer, Lloyd

1991-01-01

211

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

NASA Astrophysics Data System (ADS)

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

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

2011-03-01

212

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

213

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

NASA Technical Reports Server (NTRS)

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

Heelis, R. A.

1984-01-01

214

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

215

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

SciTech Connect

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

Jamer, Michelle E.; Assaf, Badih A.; Devakul, Trithep; Heiman, Don [Department of Physics, Northeastern University, Boston, Massachusetts 02115 (United States)] [Department of Physics, Northeastern University, Boston, Massachusetts 02115 (United States)

2013-09-30

216

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

NASA Astrophysics Data System (ADS)

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

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

1994-12-01

217

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

SciTech Connect

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

Kosuge, K.; Hirose, K.; Kuroki, K. (Nippon Steel Corp., Hyogo (Japan))

1994-12-01

218

Tb magnetic moment behaviour in amorphous Tb?Fe alloy: A nuclear orientation study  

NASA Astrophysics Data System (ADS)

Amorphous 160Tb : TbFe 4 has been studied in the temperature range down to 5 mK and in external magnetic fields up to 8.5T using the low-temperature nuclear orientation technique. The Tb magnetic moments are noncollinear with respect to Bext even up to Bext = 8.5 T. The hysteresis loop, which was reconstructed from the experimental data, shows the coercive field to be ? 1 T, which is considerably lower than in amorphous TbFe 2.

Trhlík, M.; De Moor, P.; John, J.; Limbach, T.; Schuurmans, P.; Sedlák, B.; Severijns, N.; Vanderpoorten, W.; Vanneste, L.; Wouters, J.

1993-07-01

219

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

PubMed

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

220

Orientational and magnetic ordering of buckyballs in TDAE-C60  

Microsoft Academic Search

Spin ordering in the low-temperature magnetic phase is directly linked to the orientational ordering of C60 molecules in organically doped fullerene derivatives. Electron spin resonance and alternating current susceptometry measurements on tetrakis (dimethylamino) ethylene-C60 (TDAE-C60) (Curie temperature T(sub c) = 16 kelvin) show a direct coupling between spin and merohedral degrees of freedom. This coupling was experimentally demonstrated by showing

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

1995-01-01

221

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

NASA Astrophysics Data System (ADS)

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

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

2006-09-01

222

Non-epitaxially Grown, Oriented L10 FePt Films and Their Magnetic Properties  

Microsoft Academic Search

Nanoscale magnetic materials with high magnetocrystalline anisotropy have excellent thermal stability, high coercivity and promising application such as extremely high-density recoding media. L10 FePt films exhibit a magnetocrystalline anisotropy constant as high as 3 × 10^7 erg\\/cm^3 after heat annealing and have attracted much attention. For certain applications, the orientation of the easy axis of the FePt grain should be

M. L. Yan; X. Z. Li; D. J. Sellmyer

2003-01-01

223

Magnetic resonance imaging shows orientation and asymmetry of white matter fiber tracts  

Microsoft Academic Search

Apparent diffusion tensor maps of the human brain were acquired with a magnetic resonance imaging sequence (Gudbjartsson, H., Maier, S.E., Mulkern, R.V., Mórocz, I.A., Patz, S., Jolesz, F.A., Magn. Reson. Med. 36 (1996) 509–519). It was shown that the geometric nature of the apparent diffusion tensors can quantitatively characterize the tissue structure. Display of the orientation and directional uniformity of

Sharon Peled; Hákon Gudbjartsson; Carl-Fredrik Westin; Ron Kikinis; Ferenc A. Jolesz

1998-01-01

224

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

NASA Astrophysics Data System (ADS)

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

Valach, Fridrich; Bochní?ek, Josef; Hejda, Pavel; Revallo, Miloš

2014-02-01

225

Numerical study of the one-dimensional quantum compass model  

NASA Astrophysics Data System (ADS)

The ground state magnetic phase diagram of the one-dimensional quantum compass model (QCM) is studied using the numerical Lanczos method. A detailed numerical analysis of the low energy excitation spectrum is presented. The energy gap and the spin-spin correlation functions are calculated for finite chains. Two kind of the magnetic long-range orders, the Néel and a type of the stripe-antiferromagnet, in the ground state phase diagram are identified. Based on the numerical analysis, the first and second order quantum phase transitions in the ground state phase diagram are identified.

Mahdavifar, S.

2010-09-01

226

Numerical study of the one-dimensional quantum compass model  

Microsoft Academic Search

The ground state magnetic phase diagram of the\\u000a one-dimensional quantum compass model (QCM) is studied using the\\u000a numerical Lanczos method. A detailed numerical analysis of the low\\u000a energy excitation spectrum is presented. The energy gap and the\\u000a spin-spin correlation functions are calculated for finite chains.\\u000a Two kind of the magnetic long-range orders, the Néel\\u000a and a type of the stripe-antiferromagnet,

Saeed Mahdavifar

2010-01-01

227

Self-compassion: a concept analysis.  

PubMed

This concept analysis uses a modification of the evolutionary method (Rodgers, 1989) to identify the antecedent, attributes, and consequences of self-compassion. The antecedent to self-compassion is suffering, experienced in six possible realms: an event, a situation, an emotional response, a psychological state, spiritual alienation, or a physical response to illness or pain. Suffering has three dimensions: intrapersonal, interpersonal, and contextual. Suffering manifests as a pattern of decreased self-care, decreased ability to relate to others, and diminished autonomy. The attributes of self-compassion are self-kindness, mindfulness, commonality, and wisdom. The consequences of self-compassion are the opposite of the antecedent: self-compassion manifests as a pattern of increased self-care capacity, compassion for others, and increased relatedness, autonomy, and sense of self. Ideal, borderline and contrary cases of self-compassion provide examples of the concept. The article concludes with a discussion of implications of the concept of self-compassion for nursing practice and research. PMID:22024954

Reyes, Darcel

2012-06-01

228

STUDY OF THE ANGLE OF DEPHASING BETWEEN THE VECTORS OF ROTOR AND STATOR MAGNETIC FLOW IN A SYSTEM OF CONTROL THROUGH ORIENTATION OF A MAGNETIC FIELD  

Microsoft Academic Search

This article presents results received from the study of a system of control of three-phase asynchronous motor through an orientation of a magnetic field. The controller does stabilization of the vector of rotor magnetic flow. The purpose of this study is to find how the angle of dephasing between the vectors of magnetic flows in the rotor and stator changes.

Pencho Georgiev; Dinko Gospodinov

229

A survey of quiet auroral arc orientation and the effects of the interplanetary magnetic field  

NASA Astrophysics Data System (ADS)

Using data from the THEMIS All-Sky Imager array, we have carried out an extensive study of the orientation of quiet auroral arcs relative to the magnetic east-west direction. We used over 7500 images of quiet auroral arcs that were collected during extended solar minimum and at various geomagnetic latitudes and longitudes. For each arc, we determined its "tilt" (the angle the arc makes with the local magnetic east-west direction) and its "multiplicity" (whether or not the arc was part of a multiple-arc system). We have found that at more equatorward latitudes, arc tilts are within ?SD = ±7.7?. We determined that both single- and multiple-arc systems tend to tilt a few degrees to the south-east prior to 23 magnetic local time (MLT) and to the north-east afterward. This tilt appears to be more prominent at higher latitudes. We compared the auroral arc orientations to the mapping of equatorial contours of constant magnetic field strength into the ionosphere, where we used the T87 and T89 magnetic field models for quiet (Kp = 1,3) conditions for the mappings and to determine the constant equatorial magnetic field strength contours. We found that the MLT trends of the tilts are such that arc alignment appears to follow the constant magnetic field strength contours as projected into the ionosphere. We assert that the systematic dependencies of the orientation of auroral arcs indicate that arc morphology is governed by the large-scale structure of the magnetosphere as opposed to localized processes within the ionosphere. In addition, we studied the effects of the interplanetary magnetic field (IMF) on the location in MLT of the reversal of the arc tilts. We found that negative IMF Bxand Byconditions cause the reversal location to shift duskward of 23 MLT. Alternately, a positive IMF Bx, coupled with a negative By, results in a shift in reversal location toward magnetic midnight. This behavior is consistent with that found in studies of the MLT distribution of substorm onsets.

Gillies, D. M.; Knudsen, D. J.; Donovan, E. F.; Spanswick, E. L.; Hansen, C.; Keating, D.; Erion, S.

2014-04-01

230

Mirror alignment control for COMPASS RICH-1 detector  

NASA Astrophysics Data System (ADS)

The focusing system of the COMPASS RICH-1 detector consists of two segmented spherical mirror surfaces, formed by 68 hexagonal and 48 pentagonal individual elements. All individual mirrors have two degrees of freedom to adjust the angular alignment in order to obtain a continuous spherical surface. Relative angular misalignments can be monitored on-line by the CLAM method, based on the optical reconstruction of line images. Complementing the CLAM measurements with photogrammetry, the absolute mirror orientation and position in space can be determined too. The method is described, as well as the algorithms used to access the relative and absolute mirror alignment.

Alexeev, M.; Birsa, R.; Bradamante, F.; Bressan, A.; Chiosso, M.; Ciliberti, P.; Dalla Torre, S.; Denisov, O.; Duic, V.; Ferrero, A.; Finger, M.; Finger, M.; Giorgi, M.; Gobbo, B.; Levorato, S.; Maggiora, A.; Martin, A.; Menon, G.; Panzieri, D.; Pesaro, G.; Polak, J.; Rocco, E.; Sbrizzai, G.; Schiavon, P.; Slunecka, M.; Sozzi, F.; Steiger, L.; Sulc, M.; Takekawa, S.; Tessarotto, F.

2011-05-01

231

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

NASA Astrophysics Data System (ADS)

The effect of powder properties on the degree of crystal orientation of Bi4Ti3O12 (BIT) ceramics fabricated by a high-magnetic-field method was investigated. As expected, the degree of orientation of BIT ceramics exhibited little dependence on the crystallinity of the powder, and depended on the particle size of the powder. The degree of orientation increased up to 0.96 when the particle size increased from 0.5 to 1.2 ?m. The particle size dependence of the degree of orientation was similar to the relationship between the order parameter and particle size, as derived from Langevin’s theory on magnetic alignment. This suggests that the crystal orientation of ceramics fabricated by the high-magnetic-field method can be controlled by selecting the particle size of the powder used.

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

2004-09-01

232

Strong in-plane magnetic anisotropy in (111)-oriented CoFe2O4 thin film  

NASA Astrophysics Data System (ADS)

The perfect (111)-oriented CoFe2O4 thin films were grown on Pt(111)/Si substrate by pulsed laser deposition technique at substrate temperature of 600 °C. The optimum oxygen pressure was found to be 10 mTorr based on structural and magnetic properties. The film grown at 10 mTorr has the highest (111)-orientation degree and magnetization. The films are under in-plane tensile stress due to the residual thermal strain which is thickness-dependent. It was found that the (111)-oriented CoFe2O4 thin film demonstrates the strong in-plane magnetic anisotropy which results from orientation as well as the stress-induced magnetic anisotropy.

Khodaei, M.; Seyyed Ebrahimi, S. A.; Park, Yong Jun; Ok, Jong Mok; Kim, Jun Sung; Son, Junwoo; Baik, Sunggi

2013-08-01

233

Orientational and magnetic ordering of buckyballs in TDAE-C60  

NASA Astrophysics Data System (ADS)

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

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

1995-04-01

234

Orientational and magnetic ordering of buckyballs in TDAE-C60  

SciTech Connect

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

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

1995-04-01

235

Highlights from the COMPASS experiment  

NASA Astrophysics Data System (ADS)

The Compass experiment at CERN is studying the nucleon spin structure with a 160 GeV polarized muon beam and polarized targets as well as hadron structure with 190 GeV pion, kaon and proton beams. The paper gives an overview of the results for the helicity and transverse spin structure of the nucleon. A first result from the spectroscopy experiments, the observation of a resonance with exotic JPC = 1-+ quantum numbers at 1660 MeV is also presented. The paper ends with an outlook to future measurements.

Mallot, G. K.

2010-09-01

236

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

237

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

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

1997-01-01

238

Magnetic anisotropy and crystalline orientation in high Hk FeCoB thin films  

NASA Astrophysics Data System (ADS)

FeCoB thin films with a high magnetic anisotropy field Hk were studied. Crystal structure of the FeCo was investigated by using x-Ray diffraction with particular interest for understanding the scheme to produce a high Hk in the FeCoB films. The as-deposited film with a high Hk of 280 Oe showed a well-crystallized bcc (110) texture of FeCo and an asymmetric profile in the rocking curve measured along the easy axis. The pole figure profile revealed that the maximum diffraction intensity was observed at the point other than the original point, namely, the tilted crystal orientation to the substrate plane. In addition, elliptical contour lines of diffraction intensity were observed and their major axis aligned with the direction of the peak shift. These results indicated the correlation among the crystal orientation and the easy axis direction and also the incident direction of the sputtering particles to the substrate.

Hashimoto, Atsuto; Matsuu, Toshimitsu; Tada, Masaru; Nakagawa, Shigeki

2008-04-01

239

Effect of cross shear rolling on textures and magnetic properties of grain oriented silicon steels  

SciTech Connect

By the cross shear rolling (CSR) it is understood that the rolling between two work rolls which rotate at different peripheral speeds. The characteristics of this special process are that the applied rolling load is much lower than that of conventional rolling, and that metal sheets can be rolled to a very thin thickness with high rolling precision. So far, the CSR has been successfully utilized to produce various super-thin sheets of plain materials; but its application to grain oriented silicon steels remains open, though many attempts have been made on how to reduce the thickness of steel sheets and to decrease the production cost. In this investigation, the CSR followed by hydrogen annealing was used to produce grain oriented silicon steel sheets with thickness of 0.34 mm and 0.10 mm. Some results are presented in relation to the effects of the CSR on texture and magnetic properties.

Liu, G. [Northeastern Univ., Shenyang (China). Dept. of Materials Science and Engineering] [Northeastern Univ., Shenyang (China). Dept. of Materials Science and Engineering; [Liaoning Univ., Shenyang (China). Dept. of Materials Science and Engineering; Wang, F.; Zuo, L.; Qi, K.M.; Liang, Z.D. [Northeastern Univ., Shenyang (China). Dept. of Materials Science and Engineering] [Northeastern Univ., Shenyang (China). Dept. of Materials Science and Engineering

1997-12-15

240

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

241

Solving the orientation specific constraints in transcranial magnetic stimulation by rotating fields.  

PubMed

Transcranial Magnetic Stimulation (TMS) is a promising technology for both neurology and psychiatry. Positive treatment outcome has been reported, for instance in double blind, multi-center studies on depression. Nonetheless, the application of TMS towards studying and treating brain disorders is still limited by inter-subject variability and lack of model systems accessible to TMS. The latter are required to obtain a deeper understanding of the biophysical foundations of TMS so that the stimulus protocol can be optimized for maximal brain response, while inter-subject variability hinders precise and reliable delivery of stimuli across subjects. Recent studies showed that both of these limitations are in part due to the angular sensitivity of TMS. Thus, a technique that would eradicate the need for precise angular orientation of the coil would improve both the inter-subject reliability of TMS and its effectiveness in model systems. We show here how rotation of the stimulating field relieves the angular sensitivity of TMS and provides improvements in both issues. Field rotation is attained by superposing the fields of two coils positioned orthogonal to each other and operated with a relative phase shift in time. Rotating field TMS (rfTMS) efficiently stimulates both cultured hippocampal networks and rat motor cortex, two neuronal systems that are notoriously difficult to excite magnetically. This opens the possibility of pharmacological and invasive TMS experiments in these model systems. Application of rfTMS to human subjects overcomes the orientation dependence of standard TMS. Thus, rfTMS yields optimal targeting of brain regions where correct orientation cannot be determined (e.g., via motor feedback) and will enable stimulation in brain regions where a preferred axonal orientation does not exist. PMID:24505266

Rotem, Assaf; Neef, Andreas; Neef, Nicole E; Agudelo-Toro, Andres; Rakhmilevitch, David; Paulus, Walter; Moses, Elisha

2014-01-01

242

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.

Sabatini, Angelo Maria

2012-01-01

243

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.

Barker, Jeffrey

244

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.

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

2007-01-01

245

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

246

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

NASA Astrophysics Data System (ADS)

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

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

2007-05-01

247

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

248

Coherent triplet excitation suppresses the heading error of the avian compass  

NASA Astrophysics Data System (ADS)

Radical-ion pair reactions are currently understood to underlie the biochemical magnetic compass of migratory birds. It was recently shown that radical-ion pair reactions form a rich playground for the application of quantum-information-science concepts and effects. We will show here that the intricate interplay between the quantum Zeno effect and the coherent excitation of radical-ion pairs leads to an exquisite angular sensitivity of the reaction yields. This results in a significant and previously unanticipated suppression of the avian compass heading error, opening the way to quantum engineering precision biological sensors.

Katsoprinakis, G. E.; Dellis, A. T.; Kominis, I. K.

2010-08-01

249

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

250

Self-Compassion, Stress, and Coping  

PubMed Central

People who are high in self-compassion treat themselves with kindness and concern when they experience negative events. The present article examines the construct of self-compassion from the standpoint of research on coping in an effort to understand the ways in which people who are high in self-compassion cope with stressful events. Self-compassionate people tend to rely heavily on positive cognitive restructuring but do not appear to differ from less self-compassionate people in the degree to which they cope through problem-solving and distraction. Existing evidence does not show clear differences in the degree to which people who are low vs. high in self-compassion seek support as a coping strategy, but more research is needed.

Allen, Ashley Batts; Leary, Mark R.

2010-01-01

251

COMPASS Final Report: Lunar Relay Satellite (LRS).  

National Technical Information Service (NTIS)

The Lunar Relay Satellite (LRS) COllaborative Modeling and Parametric Assessment of Space Systems (COMPASS) session was tasked to design a satellite to orbit in an elliptical lunar polar orbit to provide relay communications between lunar South Pole asset...

M. L. McGuire S. R. Oleson

2012-01-01

252

Compass 2008 Data Analysis and Reporting.  

National Technical Information Service (NTIS)

The Compass Annual Report is issued each year to communicate the condition of Wisconsins state highway network and to demonstrate accountability for maintenance expenditures. The primary audience for this report includes Maintenance Supervisors and Operat...

E. Juni T. M. Adams

2009-01-01

253

Dzyaloshinskii-Moriya interaction accounting for the orientation of magnetic domains in ultrathin films: Fe/W(110)  

NASA Astrophysics Data System (ADS)

Combining relativistic first-principles calculations with a micromagnetic model, we establish the Dzyaloshinskii-Moriya interaction as an important mechanism in thin-film magnetism, determining the orientation of magnetic domains relative to the lattice, the type of domain wall, and the rotational direction of the magnetization in the wall. Applying the analysis to two monolayers Fe on W(110), we provide an explanation for puzzling experimental data obtained by spin-polarized scanning tunneling microscopy.

Heide, M.; Bihlmayer, G.; Blügel, S.

2008-10-01

254

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.

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

2011-01-01

255

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

SciTech Connect

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

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

2006-01-01

256

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

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

257

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.

Guarendi, Andrew N.; Chandy, Abhilash J.

2013-01-01

258

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

PubMed

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

259

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

260

On-board processing for the COMPASS  

NASA Astrophysics Data System (ADS)

The Compact Airborne Spectral Sensor (COMPASS) is a hyperspectral sensor covering the 400 to 2350 nm spectral region using a single focal plane and a very compact optical system. In addition, COMPASS will include a high-resolution panchromatic imager. With its compact design and its full spectral coverage throughout the visible, near infrared and SWIR, COMPASS represents a major step forward in the practical utilization of hyperspectral sensors for military operations. COMPASS will be deployed on a variety of airborne platforms for the detection of military objects of interest. There was considerable interest in the development of an on-board processor for COMPASS. The purpose of this processor is to calibrate the data and detect military targets in complex background clutter. Because of their ability to operate on truly hyperspectral data consisting of a hundred or more bands, linear unmixing algorithms were selected for the detection processor. The N-FINDR algorithm that automatically finds endmembers and then unmixes the scene was selected for real-time implementation. In addition, a recently developed detection algorithm, Stochastic Target Detection (STD), which was specifically designed for compatibility with linear unmixing algorithms, was chosen for the detection step. The N-FINDR/STD algorithm pair was first tested on a variety of hyperspectral data sets to determine its performance level relative to existing hyperspectral algorithms (such as RX) using Receiver Operator Curves (ROC) as the basis. Following completion of the testing, a hardware implementation of a real time processor for COMPASS using commercial off-the-shelf computer technology was designed. The COMPASS on-board processor will consist of the following elements: preprocessing, N-FINDR endmember determination and linear unmixing, the STD target detection step, and the selection of a High Resolution Image Chip covering the target area. Computer resource projections have shown that these functions, along with supporting interactive display functions, can operate in real-time on COMPASS data using multi-processor Pentium III class processors.

Simi, Christopher G.; Winter, Edwin M.; Schlangen, Michael J.; Hill, Anthony B.

2001-08-01

261

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

262

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.

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

2013-01-01

263

Oriented immobilization of galactose oxidase to bead and magnetic bead cellulose and poly(HEMA-co-EDMA) and magnetic poly(HEMA-co-EDMA) microspheres.  

PubMed

In order to obtain an active and stable oxidation reactor for daily use in biochemical laboratory we decided to immobilize galactose oxidase orientedly through a carbohydrate chain to the magnetic carriers. We used hydrazide derivatives of non-magnetic and magnetic bead cellulose and of magnetic and non-magnetic poly(HEMA-co-EDMA) microspheres. Activation of the enzyme molecules was done by sodium periodate in the presence of supplements (fucose, CuSO4, catalase). Orientedly immobilized galactose oxidase presents high storage stability and lower susceptibility to inappropriate microenvironmental conditions. Reactor reactivated by three pulses of D-galactose retained practically 100% of its native activity after 6 months. The positive properties of both magnetic carriers were entirely confirmed. PMID:12013233

Bílková, Zuzana; Slováková, Marcela; Lycka, Antonín; Horák, Daniel; Lenfeld, Jirí; Turková, Jaroslava; Churácek, Jaroslav

2002-04-25

264

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

265

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

NASA Astrophysics Data System (ADS)

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

Fujimura, Hiroshi; Nitomi, Hirokatsu; Yashiki, Hiroyoshi

266

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

267

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

PubMed

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

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

2014-01-01

268

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

SciTech Connect

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

Wang Xuewei, E-mail: xwwang@tjut.edu.cn [School of Materials Science and Engineering, Tianjin University of Technology, Tianjin 300384 (China); Tianjin Key Lab for Photoelectric Materials and Devices, Tianjin 300384 (China); Yuan Zhihao [School of Materials Science and Engineering, Tianjin University of Technology, Tianjin 300384 (China); Key Laboratory of Display Materials and Photoelectric Devices (Tianjin University of Technology), Ministry of Education, Tianjin 300384 (China); Li Jushan [School of Materials Science and Engineering, Tianjin University of Technology, Tianjin 300384 (China)

2011-06-15

269

Circuits and Magnetic Fields  

NSDL National Science Digital Library

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

Vu Bioengineering Ret Program

270

Quick recovery of orientation after 100 Hz magnetic seizure therapy (MST) for major depressive disorder  

PubMed Central

Introduction Magnetic seizure therapy (MST), in which seizures are elicited with a high-frequency magnetic field, is under development as a new treatment for major depressive disorder. Its use may be justified if it produces the antidepressant effects of ECT, coupled with limited cognitive side effects. This pilot study reports shortened recovery times after MST compared with ECT as a preliminary step to evaluate the usefulness of a new 100Hz MST device. Methods We induced seizures with 100Hz magnetic transcranial stimulation in eleven patients with major depressive disorder during one session of a regular course of ECT. Recovery times after these MST and ECT induced seizures were compared. Results Seizures could be elicited in ten of the eleven patients. Stimulation over the vertex produced tonic-clonic activity on nine out of eleven occasions. Stimulation over the prefrontal midpoint elicited seizures on three out of seven occasions. The mean duration of magnetically induced seizures was 31.3 sec, ranging from 10-86 sec. All patients had an exceptionally quick recovery of orientation: mean of 7 min 12 sec (SD = 2 min 7 sec, range 4 min 20 sec – 9 min 41 sec). The recovery times were on average 15 min 35 sec shorter with MST than with ECT in the same patients (paired-samples t-test: p = 0.00009). Patients reported feeling less confused after MST. Side effects were confined to myoclonic movements, associated with the use of etomidate. Conclusions The new 100 Hz magnetic stimulator elicits seizures in the majority of patients when administered over the vertex. MST was associated with shorter recovery times and less confusion following treatment. Subsequent work will be required to assess the safety and effectiveness of MST in the treatment of depression.

Kirov, George; Ebmeier, Klaus P.; Scott, Allan I F; Atkins, Maria; Khalid, Najeeb; Carrick, Lucy; Stanfield, Andrew; O'Carroll, Ronan E.; Husain, Mustafa M.; Lisanby, Sarah H.

2008-01-01

271

Real-time WAXS study of induced orientation in a liquid crystalline polyester under the influence of a magnetic field  

Microsoft Academic Search

The in situ variation of induced orientation within a liquid crystalline polyester under the influence of a magnetic field was investigated during heat treatment, by means of wide-angle X-ray scattering (WAXS) using synchrotron radiation. The kinetics of molecular orientation, both from the melt and from the solid state, is analyzed in a wide temperature range (T=190–260°C) in terms of the

F Ania; A Flores; H. R Kricheldorf; F. J Baltá-Calleja

2003-01-01

272

Spin-orientation phase transitions in Nd2CuO4: A compound with noncollinear magnetic structure  

Microsoft Academic Search

We report magnetization measurements of ND2CuO4 single crystals in the temperature range 0.5-4.2 K in static and pulsed magentic fields. Two spin-orientation phase transitions, one of the first order (Hc1=4.4 T, H[100]) and another one of the second order (Hc2=0.75 T, H[110]), were observed at 0.7 K for different field orientation. This allows us to conclude that at low temperatures

A. S. Cherny; E. N. Khats'ko; G. Chouteau; J. M. Louis; A. A. Stepanov; P. Wyder; S. N. Barilo; D. I. Zhigunov

1992-01-01

273

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

274

A new stator-flux orientation strategy for flux-switching permanent magnet motor based on current-hysteresis control  

NASA Astrophysics Data System (ADS)

A stator-flux orientation strategy based on current hysteresis for the flux-switching permanent magnet (FSPM) motor is proposed, in which the stator-PM FSPM motor is considered as a conventional rotor-PM surface-mounted motor and an equivalent rotor-orientated dq-axes synchronous reference frame is built although there are actually no rotary magnetic motive force produced by the stator magnets in the FSPM motor. Based on the proposed model, a vector-control strategy with current hysteresis for the FSPM motor drive is investigated and implemented on a dSPACE-based platform, and both the simulated and experimental results validate the effectiveness. It should be emphasized that the proposed stator-flux orientation strategy can be applied to other stator-PM machines (including doubly salient and flux-reversal PM machines) and other control methods (including space-vector pulsed-width-modification and direct torque control).

Hua, Wei; Cheng, Ming; Lu, Wei; Jia, Hongyun

2009-04-01

275

Geomagnetic Navigation beyond the Magnetic Compass  

Microsoft Academic Search

Increasing uncertainty regarding the reliability of Global Navigation Satellite Systems (GNSS) has led the navigation community to seek valuable alternatives. Aerospace navigation by integration of inertial systems with reference to maps of Geophysical Fields of the Earth (GFE) is a promising area which can be highly advanced utilizing tremendous achievements in embedded micro-processing, including the memory devices capability and miniature

Felix Goldenberg

2006-01-01

276

Synthesis of orientedly bioconjugated core\\/shell Fe 3O 4@Au magnetic nanoparticles for cell separation  

Microsoft Academic Search

Orientedly bioconjugated core\\/shell Fe3O4@Au magnetic nanoparticles were synthesized for cell separation. The Fe3O4@Au magnetic nanoparticles were synthesized by reducing HAuCl4 on the surfaces of Fe3O4 nanoparticles, which were further characterized in detail by TEM, XRD and UV–vis spectra. Anti-CD3 monoclonal antibody was orientedly bioconjugated to the surface of Fe3O4@Au nanoparticles through affinity binding between the Fc portion of the antibody

Yi-Ran Cui; Chao Hong; Ying-Lin Zhou; Yue Li; Xiao-Ming Gao; Xin-Xiang Zhang

277

Relaxation Phenomena of a Magnetic Nanoparticle Assembly with Randomly Oriented Anisotropy  

NASA Astrophysics Data System (ADS)

The effects of a randomly oriented anisotropy on relaxation phenomena including the memory effect of a noninteracting magnetic nanoparticle assembly, are numerically studied with a localized partition function and a master equation, leading to the following results. During the zero-field-cooled (ZFC) process, the energy barrier histogram changes with temperature, while during the field-cooled (FC) process it remains stable. In the relaxation process after ZFC initialization, the effective energy barrier distribution, which is derived from the T\\ln(t/?0) (T temperature, t time, and ?0 characteristic time constant) scaling curve, only reflects the low-energy region of the energy barrier histogram. The memory effect with temporary cooling during time evolution occurs in the studied assembly even without volume distribution and particle interaction involved.

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

2011-03-01

278

Magnetically oriented dodecylphosphocholine bicelles for solid-state NMR structure analysis.  

PubMed

A mixture of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) with the short-chain detergent n-dodecylphosphocholine (DPC) is introduced here as a new membrane-mimetic bicelle system for solid-state NMR structure analysis of membrane proteins in oriented samples. Magnetically aligned DMPC/DPC bicelles are stable over a range of concentrations, with an optimum lipid ratio of q=3:1, and they can be flipped with lanthanide ions. The advantage of DMPC/DPC over established bicelle systems lies in the possibility to use one and the same detergent for purification and NMR analysis of the membrane protein, without any need for detergent exchange. Furthermore, the same batch of protein can be studied in both micelles and bicelles, using liquid-state and solid-state NMR, respectively. The applicability of the DMPC/DPC bicelles is demonstrated here with the (15)N-labeled transmembrane protein TatA. PMID:22274567

Nolandt, Olga V; Walther, Torsten H; Grage, Stephan L; Ulrich, Anne S

2012-05-01

279

Effects of magnetic fields on mosquitoes.  

PubMed

Phylogenetically diverse organisms, including some insects, are able to detect and respond to magnetic fields comparable to the Earth's magnetic field. Because of their tremendous importance to public health, mosquitoes were tested for the presence of remanent ferromagnetic material indicative of a biological compass and also tested for behavioral responses to magnetic fields. Using a superconducting quantum interferometry device, we found that significant remnant was probably due to attraction of ferromagnetic dust onto the surface of live or dead mosquitoes. Most mosquitoes placed in a 1.0-gauss, uniform magnetic field moved until they were oriented parallel to the field. Two of 3 species of mosquitoes tested took fewer blood meals in a rotating magnetic field than in the Earth's normal magnetic field. PMID:10901636

Strickman, D; Timberlake, B; Estrada-Franco, J; Weissman, M; Fenimore, P W; Novak, R J

2000-06-01

280

Gluon polarization measurements at COMPASS  

NASA Astrophysics Data System (ADS)

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

Silva, Luís; COMPASS Collaboration

2012-10-01

281

Exact solution for a quantum compass ladder  

NASA Astrophysics Data System (ADS)

We present a spin ladder with antiferromagnetic Ising ZZ interactions along the legs and interactions on the rungs which interpolate between the Ising ladder and the quantum compass ladder. We show that the entire energy spectrum of the ladder may be determined exactly for finite number of spins 2N by mapping to the quantum Ising chain and using Jordan-Wigner transformation in invariant subspaces. We also demonstrate that subspaces with spin defects lead to excited states using finite-size scaling, and the ground state corresponds to the quantum Ising model without defects. At the quantum phase transition to maximally frustrated interactions of the compass ladder, the ZZ spin-correlation function on the rungs collapses to zero and the ground-state degeneracy increases by two. We formulate a systematic method to calculate the partition function for a mesoscopic system and employ it to demonstrate that fragmentation of the compass ladder by kink defects increases with increasing temperature. The obtained heat capacity of a large compass ladder consisting of 2N=104 spins reveals two relevant energy scales and has a broad maximum due to dense energy spectrum. The present exact results elucidate the nature of the quantum phase transition from ordered to disordered ground state found in the compass model in two dimensions.

Brzezicki, Wojciech; Ole?, Andrzej M.

2009-07-01

282

Compass model on a ladder and square clusters  

Microsoft Academic Search

We obtained exact specific heat of the quantum compass model on the square L × L clusters with L = 2, 3, 4, 5 using Kernel Polynomial Method and compare them with the specific heat of a large compass ladder. Intersite correlations found in the ground state for these systems demonstrate that the quantum compass model differs from its classical

Wojciech Brzezicki; Andrzej M. Oles

2010-01-01

283

Compass model on a ladder and square clusters  

NASA Astrophysics Data System (ADS)

We obtained exact specific heat of the quantum compass model on the square L × L clusters with L = 2, 3, 4, 5 using Kernel Polynomial Method and compare them with the specific heat of a large compass ladder. Intersite correlations found in the ground state for these systems demonstrate that the quantum compass model differs from its classical version.

Brzezicki, Wojciech; Ole?, Andrzej M.

2010-01-01

284

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

285

Utilization of extended BH curve method for consideration of 2-D magnetic properties of non-oriented electrical steels on motors  

Microsoft Academic Search

The motor performances such as torque characteristics or iron loss are strongly affected by the magnetic properties of electrical steel sheet used. It is found recently that, even in the non-oriented electrical steel sheets, the magnetic characteristics are dependent on the direction of the applied magnetic field, i.e., the non-oriented electrical steel sheet has two-dimensional (2D) magnetic properties. In this

Heesung Yoon; Pan Seok Shin; Chang Seop Koh

2010-01-01

286

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

287

Polarized Drell-Yan studies at COMPASS  

NASA Astrophysics Data System (ADS)

The COMPASS experiment at CERN will soon start a new series of measurements using a pion beam and a transversely polarized target. The study of the polarized Drell-Yan process will provide an insight of the transverse momentum dependent parton distribution functions (TMDs), which is complementary to their extraction from semi-inclusive deep inelastic scattering (SIDIS), previously measured in COMPASS. The sign change of Sivers and Boer-Mulders TMDs, when accessed from SIDIS or Drell-Yan, is predicted by theory. Its experimental observation is considered an essential test of the TMD approach. The experimental aspects of the Drell-Yan measurement in COMPASS are discussed. The set-up optimization, driven by the results of several beam tests are presented, as well as the expected event rates and statistical errors of the azimuthal asymmetries.

Quintans, Catarina

2014-03-01

288

Hadron spectroscopy with COMPASS at CERN  

NASA Astrophysics Data System (ADS)

The aim of the COMPASS hadron program is to study the light-quark hadron spectrum, and in particular, to search for evidence of hybrids and glueballs. COMPASS is a fixed-target experiment at the SPS at CERN and features a two-stage spectrometer with high momentum resolution, large acceptance, particle identification and calorimetry. A short pilot run in 2004 resulted in the observation of a spin-exotic state with JPC=1-+ consistent with the debated ?1(1600). In addition, Coulomb production at low momentum transfer data provide a test of chiral perturbation theory. During 2008 and 2009, a world leading data set was collected with the hadron beam, which is currently being analysed. The large statistics allows for a thorough decomposition of the data into partial waves. The COMPASS hadron data span over a broad range of channels and shed light on several different aspects of quantum chromodynamics.

Schönning, Karin; COMPASS Collaboration

2012-10-01

289

The neurobiological link between compassion and love.  

PubMed

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

Esch, Tobias; Stefano, George B

2011-02-25

290

The neurobiological link between compassion and love  

PubMed Central

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

Esch, Tobias; Stefano, George B.

2011-01-01

291

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

292

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.

Exploratorium, The

2011-12-05

293

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.

294

The role of the underwater polarized light pattern, in sun compass navigation of the grass shrimp, Palaemonetes vulgaris  

Microsoft Academic Search

1.The sky polarized light pattern is visible underwater within the critical angle of refraction and can be used to position the sun in the sky. The present study determined whether the shrimp, Palaemonetes vulgaris could use this polarization pattern for sun compass orientation.2.In the laboratory, Palaemonetes oriented parallel to the e-vector of downwelling polarized light regardless of their phototactic state.

Sydnee M. Goddard; Richard B. Forward

1991-01-01

295

Preparation of oriented bulk 5 wt% Y 2O 3–AlN ceramics by slip casting in a high magnetic field and sintering  

Microsoft Academic Search

Preparation of oriented AlN bulk ceramics was achieved by slip casting in a high magnetic field. The c-axis of AlN was perpendicular to the direction of a magnetic field. The mechanical properties and the thermal conductivity of the textured AlN depend on the direction of the crystallographic orientation.

Tohru S. Suzuki; Yoshio Sakka

2005-01-01

296

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

297

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

298

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

NASA Astrophysics Data System (ADS)

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

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

2002-08-01

299

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

PubMed

Dynamic birefringence in a ferrofluid subjected to crossed bias (constant) and probing (pulse or ac) fields is considered, assuming that the nanoparticles have finite magnetic anisotropy. This is done on the basis of the general Fokker-Planck equation that takes into account both internal magnetic and external mechanical degrees of freedom of the particle. We describe the orientation dynamics in terms of the integral relaxation time of the macroscopic orientation order parameter. To account for an arbitrary relation between the bias (external) and anisotropy (internal) fields, an interpolation expression for the integral relaxation time is proposed and justified. A developed description is used to interpret the measurements of birefringence relaxation in magnetic fluids with nanoparticles of high (cobalt ferrite) and low (maghemite) anisotropy. The proposed theory appears to be in full qualitative agreement with all the experimental data available. PMID:12241160

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

2002-08-01

300

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

301

Compassion training alters altruism and neural responses to suffering  

PubMed Central

Compassion is a key motivator of altruistic behavior, but little is known about individuals’ capacity to cultivate compassion through training. We examined whether compassion may be systematically trained by testing whether (i) short-term compassion training increases altruistic behavior, and (ii) individual differences in altruism are associated with training-induced changes in neural responses to suffering. In healthy young adults, we found that compassion training increased altruistic redistribution of funds to a victim encountered outside of the training context. Furthermore, greater altruistic behavior after compassion training was associated with altered activation in regions implicated in social cognition and emotion regulation, including the inferior parietal cortex, dorsolateral prefrontal cortex (DLPFC), and DLPFC connectivity with the nucleus accumbens. These results suggest that compassion can be cultivated with training, where greater altruistic behavior may emerge from increased engagement in neural systems implicated in understanding the suffering of others, executive and emotional control, and reward processing.

Weng, Helen Y.; Fox, Andrew S.; Shackman, Alexander J.; Stodola, Diane E.; Caldwell, Jessica Z. K.; Olson, Matthew C.; Rogers, Gregory M.; Davidson, Richard J.

2013-01-01

302

Thickness dependence of high-frequency magnetic properties in the oriented hcp-CoIr soft magnetic films with negative magnetocrystalline anisotropy  

NASA Astrophysics Data System (ADS)

The c-axis oriented hcp-Co83Ir17 soft magnetic thin films with in-plane uniaxial anisotropy and negative magnetocrystalline anisotropy (Kugrain) were fabricated at 500 °C, and thickness dependence of their high-frequency magnetic properties was investigated. Both the saturation magnetization and Kugrain are improved compared with those of the samples fabricated at room temperature in previous reports. As the introduction of negative Kugrain, the natural resonance frequency is improved without affecting the initial permeability. With CoIr thickness increasing from 55 nm to 270 nm, the initial permeability decreases slightly; the natural resonance frequency increases and then changes little; the damping constant decreases gradually.

Zhang, Sha; Xu, Fei; Ma, Xiaoming; Wang, Tao; Tan, Guoguo; Li, Fashen

2014-04-01

303

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

304

Compassion fatigue: nurse grief…who cares?  

Microsoft Academic Search

The loss of a patient or a coworker through sudden death can be a shattering experience. The purpose of this presentation was to provide information on compassion fatigue. This presentation covered the affect of repeated traumatic death on nurses. The presentation was divided into two parts. In the first part, the presenter reviewed nurses as disenfranchised grievers, identified characteristics of

Barbara Rubel

2004-01-01

305

New procedures for the calibration of COMPASS  

NASA Astrophysics Data System (ADS)

The Compact Airborne Spectral Sensor (COMPASS) has been flying for over a year and has gathered data in support of a variety of missions. While COMPASS is an array imaging spectrometer, the quality of the spectrometer optics and the alignment of the instrument during assembly have removed many of the sources of error often present in array imaging spectrometers, such as spectral band mis-registration, smile and keystone. Since COMPASS has begun flying, we have been studying new procedures for improving the calibration of the COMPASS sensor and array imaging spectrometers, in general. The use of the on-board calibration sources was compared to using a combination of on-board sources and a scene average, and also compared to using laboratory calibration sources. In addition, different methods for finding and removing bad detectors were investigated. The coupling of the bad detector replacement procedure with the flatfielding was also studied. We have found that bracketing the light levels in the scene is the key to reducing the effect of bad detectors. An effective method of bracketing the scene is to use the scene average for each detector as the white and the on-board dark. Alternative methods using multiple white sources are also attractive. Several examples from collected scene data will be presented and evaluated in terms of image quality in particular bands and Principal Components.

Simi, Christopher G.; Winter, Edwin M.; Dixon, Roberta

2004-08-01

306

Compassion and Mindfulness in Research among Colleagues  

ERIC Educational Resources Information Center

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

Conklin, Hilary

2009-01-01

307

Orbital Compass Model in a Checkerboard Lattice  

Microsoft Academic Search

The orbital compass model in a checkerboard lattice is studied. There is a competition between the interaction for the z component of the orbital pseudo-spin along the vertical\\/horizontal direction and the interaction for the x component along the diagonal direction in a checkerboard lattice. In a frustration point where the two interactions compete with each other, a macroscopic number of

Joji Nasu; Sumio Ishihara

2011-01-01

308

Exact solution for a quantum compass ladder  

Microsoft Academic Search

We present a spin ladder with antiferromagnetic Ising ZZ interactions along the legs and interactions on the rungs which interpolate between the Ising ladder and the quantum compass ladder. We show that the entire energy spectrum of the ladder may be determined exactly for finite number of spins 2N by mapping to the quantum Ising chain and using Jordan-Wigner transformation

Wojciech Brzezicki; Andrzej M. Oles

2009-01-01

309

The Geography of Compassion in Volunteer Tourism  

Microsoft Academic Search

Volunteer tourism is at the center of new concerns over the ethical consumption of tourism experiences. As one link in a broader chain of expansion of neoliberal moral economies in the West, volunteer tourism participants coproduce a ‘geography of compassion’ that maps onto the ‘Third World’ and the children who live there. Drawing on 15 months of ethnographic fieldwork in

Mary Mostafanezhad

2012-01-01

310

An efficient general algorithm for the simulation of magnetic resonance spectra of orientationally disordered solids  

NASA Astrophysics Data System (ADS)

We present an efficient and general algorithm for the simulation of EPR powder spectra. The method is based on the accumulation of a large number of single-crystal spectra. Only 2-10% of these spectra are computed by exact diagonalization of the spin-Hamiltonian matrix, whereas the other spectra are obtained by separate bicubic spline interpolation procedures for the spectral positions and intensities of all relevant transitions. The energy-level tracking scheme required for the correct interpolation of the resonance position uses the inproduct matrix of the eigenvectors of the spin-Hamiltonian matrices calculated for two subsequent orientations of the magnetic field. The procedure can be easily included in any general spin-Hamiltonian program. The merits of the method are demonstrated with the simulation of the spectrum of Re(IV) in TiO ( S = {3}/{2}, I = {5}/{2}, two isotopes Dzz = 40,000 × 10 -4cm -1) at X band. The computing time as compared to that of an algorithm without interpolation was reduced by a factor of 10 without deterioration of the resulting simulated powder spectrum.

Gribnau, M. C. M.; van Tits, J. L. C.; Reijerse, E. J.

311

Solar poloidal magnetic field orientation causing periodicity in daily variation of cosmic ray intensity  

NASA Astrophysics Data System (ADS)

A detailed analysis of the Deep River neutron monitor (NM) data for four different phases of solar activity cycle and for four groups of days chosen according to their different geomagnetic conditions is being carried out. It is found that the 60 quiet day (QD) in a year serve a better purpose for investigating the short/long term variation in cosmic ray (CR) intensity. Further, data has been harmonically analysed for the period 1964-95 to investigate the effect of solar poloidal magnetic field (SPMF) orientation in daily variation (diurnal/semi-diurnal) of CR on geomagnetically QD. The phase of the diurnal and semi-diurnal anisotropy vectors on QD has shown a significant shift to early hours when the SPMF in the northern hemisphere (NH) is positive during the periods 1971-79 and 1992-95 as compared to that during the periods 1964-70 and 1981-90 when the SPMF in NH is negative, showing a periodic nature of daily variation in CR intensity with SPMF.

Kumar, Santosh; Agarwal, Rekha; Mishra, Rajesh; Dubey, S. K.

2002-06-01

312

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

313

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.

Pescaru, Dan; Curiac, Daniel-Ioan

2014-01-01

314

Coherent triplet excitation suppresses the heading error of the avian compass  

Microsoft Academic Search

Radical-ion pair reactions are currently understood to underlie the biochemical magnetic compass of migratory birds. It was recently shown that radical-ion pair reactions form a rich playground for the application of quantum-information-science concepts and effects. We will show here that the intricate interplay between the quantum Zeno effect and the coherent excitation of radical-ion pairs leads to an exquisite angular

G. E. Katsoprinakis; A. T. Dellis; I. K. Kominis

2010-01-01

315

Quantum phase transition of the one-dimensional transverse-field compass model  

Microsoft Academic Search

The quantum phase transition (QPT) of the one-dimensional (1D) quantum compass model in a transverse magnetic field is studied in this paper. An exact solution is obtained by using an extended Jordan and Wigner transformation to the pseudospin operators. The fidelity susceptibility, the concurrence, the block-block entanglement entropy, and the pseudospin correlation functions are calculated with antiperiodic boundary conditions. The

Ke-Wei Sun; Qing-Hu Chen

2009-01-01

316

Sustained Quantum Coherence and Entanglement in the Avian Compass  

NASA Astrophysics Data System (ADS)

In artificial systems, quantum superposition and entanglement typically decay rapidly unless cryogenic temperatures are used. Could life have evolved to exploit such delicate phenomena? Certain migratory birds have the ability to sense very subtle variations in Earth’s magnetic field. Here we apply quantum information theory and the widely accepted “radical pair” model to analyze recent experimental observations of the avian compass. We find that superposition and entanglement are sustained in this living system for at least tens of microseconds, exceeding the durations achieved in the best comparable man-made molecular systems. This conclusion is starkly at variance with the view that life is too “warm and wet” for such quantum phenomena to endure.

Gauger, Erik M.; Rieper, Elisabeth; Morton, John J. L.; Benjamin, Simon C.; Vedral, Vlatko

2011-01-01

317

Progress in rapid tomography for the COMPASS tokamak  

NASA Astrophysics Data System (ADS)

After its reinstallation in Prague, the COMPASS tokamak has completed its first year of operation. In this period, among others the first set of Soft X-ray, bolometric and visible light profile cameras has been installed and commissioned. Three more sets (under construction) shall be installed at different ports of the same toroidal sector allowing for plasma tomography with a prospective of real-time processing. A dedicated tomography algorithm for the planned setup was developed, including set-up of the contribution matrix and speed optimization. The proposed code is based on robust and validated post-processing tomography algorithm with a potential to ensue and refine a simplified real-time version. The code implements rapid Minimum Fisher Regularization with optional unisotropic smoothing constrained by magnetic flux surfaces. Reconstruction on simulated data (phantom plasma emissivity models) provided quantitative evaluation of the tomography performance in the designed diagnostic set-up.

Mlynar, Jan; Weinzettl, Vladimir; Odstrcil, Michal

2010-11-01

318

Sustained quantum coherence and entanglement in the avian compass.  

PubMed

In artificial systems, quantum superposition and entanglement typically decay rapidly unless cryogenic temperatures are used. Could life have evolved to exploit such delicate phenomena? Certain migratory birds have the ability to sense very subtle variations in Earth's magnetic field. Here we apply quantum information theory and the widely accepted "radical pair" model to analyze recent experimental observations of the avian compass. We find that superposition and entanglement are sustained in this living system for at least tens of microseconds, exceeding the durations achieved in the best comparable man-made molecular systems. This conclusion is starkly at variance with the view that life is too "warm and wet" for such quantum phenomena to endure. PMID:21405313

Gauger, Erik M; Rieper, Elisabeth; Morton, John J L; Benjamin, Simon C; Vedral, Vlatko

2011-01-28

319

Meson structure in soft hadronic reactions at COMPASS  

SciTech Connect

The measurement of the electric ({alpha}-bar{pi}) and magnetic ({beta}-bar{pi}) pion polarizabilities supplies a significant test of QCD predictions in particular in the framework of the chiral perturbation theory.In this perspective we have measured with the COMPASS spectrometer the t-dependence of the cross section for the reactions: {pi}- + Z {yields} {pi}- + Z + {gamma}, and {mu}- + Z {yields} {mu}- + Z + {gamma} selecting events corresponding to the Compton {pi}{gamma} and {mu}{gamma} scattering respectively. From a fit of the data of the first reaction we can extract {alpha}-bar{pi} and {beta}-bar{pi}, from those of the second the point-like contribution. This procedure minimizes the systematic errors. Details on the experiment and the present status of the analysis of the data collected in 2004 will be discussed.

Colantoni, M. [Universita del Piemonte Orientate e INFN-To (Italy)

2006-02-11

320

Influence of magnetic field orientation on the Zeeman spin-splitting in InGaAs quantum point contacts  

NASA Astrophysics Data System (ADS)

We present measurements of the Zeeman spin-splitting in a quantum point contact (QPC) etched into an InGaAs/InP heterostructure [1], comparing magnetic field orientations in the plane and perpendicular to the InGaAs quantum well. We observe an isotropic Zeeman splitting for fields oriented in the plane of the quantum well, with a magnitude that is enhanced by up to a factor of two compared to two-dimensional electron systems in InGaAs/InP [2]. The Zeeman splitting is much larger when the magnetic field is perpendicular to the quantum well, resulting in a g-factor of 15.7 in the one dimensional limit. [4pt] [1] T. P. Martin, et al., Appl. Phys. Lett. 93, 012105 (2008).[0pt] [2] B. Kowalski, et al., Phys. Rev. B 49, 14786 (1994).

Martin, Theodore; Szorkovszky, Alex; Micolich, Adam; Hamilton, Alex; Marlow, Colleen; Taylor, Richard; Linke, Heiner; Xu, Hongqi

2010-03-01

321

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

Microsoft Academic Search

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

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

2009-01-01

322

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

Microsoft Academic Search

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

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

2001-01-01

323

Self-biased circulator\\/isolator at millimeter wavelengths using magnetically oriented polycrystalline strontium M-type hexaferrite  

Microsoft Academic Search

A self-biased circulator\\/isolator operating at millimeter wavelength has been designed, fabricated, and tested. The ferrite material used in the device, magnetically oriented polycrystalline strontium M-type hexaferrite (SrFe12O19, SrM), was characterized by vibrating sample magnetometer and ferromagnetic resonance. The measurement of S-parameters indicated that at 41 GHz, the isolation was 28 dB and the insertion loss was 4 dB.

Xu Zuo; Hoton How; S. Somu; C. Vittoria

2003-01-01

324

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

325

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

SciTech Connect

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

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

2010-08-16

326

ComPaSS: efficient communication services for scalable architectures  

Microsoft Academic Search

In massively parallel computers (MPCS), efictent communicat~on among processors is critzcal to performance. This paper describes the znzt~al implementation of the ComPaSS communication library to support scalable software development in MPCS. ComPaSS provides hxgh-level global commun~cation operations for both data manipulation and process control, many of which are based upon a small set of low-level communication prim$ttves. The ComPaSS ltbrary

Philip K. McKinley; Hong Xu; Edgar T. Kalns; Lionel M. Ni

1992-01-01

327

Self-compassion, Achievement Goals, and Coping with Academic Failure  

Microsoft Academic Search

Two studies examined the relationship between self-compassion, academic achievement goals, and coping with perceived academic failure among undergraduates. Self-compassion entails being kind to oneself in instances of failure, perceiving one's experiences as part of the larger human experience, and holding painful feelings in mindful awareness. Study 1 (N?=?222) found that self-compassion was positively associated with mastery goals and negatively associated

KRISTIN D. NEFF; Ya-Ping Hsieh; Kullaya Dejitterat

2005-01-01

328

Orientation of the Magnetic Fields in Interplanetary Flux Ropes and Solar Filaments  

Microsoft Academic Search

Coronal mass ejections (CMEs) are often associated with erupting magnetic structures or disappearing filaments. The majority of CMEs headed directly toward the Earth are observed at 1 AU as magnetic clouds-the region in the solar wind where the magnetic field strength is higher than average and there is a smooth rotation of the magnetic field vectors. The three-dimensional structure of

Vasyl B. Yurchyshyn; Haimin Wang; Philip R. Goode; Yuanyong Deng

2001-01-01

329

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

PubMed

Form factor and magnetic properties of silica-coated spindle-type hematite nanoparticles are determined from SAXS measurements with applied magnetic field and magnetometry measurements. The particle size, polydispersity and porosity are determined using a core-shell model for the form factor. The particles are found to align with their long axis perpendicular to the applied field. The orientational order is determined from the SAXS data and compared to the orientational order obtained from magnetometry. The direct access to both, the orientational order of the particles, and the magnetic moments allow one to determine the magnetic properties of the individual spindle-type hematite particles. We study the influence of the silica coating on the magnetic properties and find a fundamentally different behavior of silica-coated particles. The silica coating reduces the effective magnetic moment of the particles. This effect is enhanced with field strength and can be explained by superparamagnetic relaxation in the highly porous particles. PMID:20329762

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

2010-04-15

330

Unpolarized azimuthal asymmetries in SIDIS at COMPASS  

NASA Astrophysics Data System (ADS)

The study of the spin structure of the nucleon and of the effects due to the quarks transverse momentum are part of the scientific program of COMPASS, a fixed target experiment at the CERN SPS. The azimuthal modulations which appear in the cross-section of SIDIS off unpolarised targets give insight on the intrinsic momentum structure of the nucleon and on the possible correlation between transverse spin and transverse momentum of the quarks. We present the results for the amplitudes of the cos(?), cos(2?), and sin(?) modulatuions (where ? is the azimuthal hadron angle in the gamma-nucleon system) obtained from the COMPASS data collected with a 160 GeV/c positive muon beam impinging on a deuteron target. The amplitudes are measured for both positive and negative hadrons, and the results on the dependence of the relevant kinematical variables obtained after a multi dimensional analysis are also presented.

Sbrizzai, G.

2014-01-01

331

Proposal for GPD studies at COMPASS  

SciTech Connect

The study of nucleon structure through Generalised Parton Distributions (GPD) is one major part of the future COMPASS-II physics program and can be performed using exclusive reactions like Deeply Virtual Compton Scattering (DVCS) and Meson Production. The high energy of the muon beam allows to measure the x{sub B}-dependence of the t-slope of the DVCS cross section. The use of positive and negative polarised muon beams allows to determine the Beam Charge and Spin Difference of the DVCS cross sections to access the real part of the Compton form factor related to the dominant GPD H. The sensitivity of both measurements is examined and confronted to existing models or global fits of the data. Preliminary beam test data were analyzed and demonstrated the feasibility of the identification of the DVCS reaction using the COMPASS experimental set-up.

Burtin, E. [CEA-Centre de Saclay Irfu, Service de Physique Nucleaire F-91191 Gif-sur Yvette Cedex (France)

2011-10-24

332

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

Microsoft Academic Search

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

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

1988-01-01

333

The installation and correction of compasses in airplanes  

NASA Technical Reports Server (NTRS)

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

Schoeffel, M F

1927-01-01

334

COMPASS: A general purpose computer aided scheduling tool  

NASA Technical Reports Server (NTRS)

COMPASS is a generic scheduling system developed by McDonnell Douglas under the direction of the Software Technology Branch at JSC. COMPASS is intended to illustrate the latest advances in scheduling technology and provide a basis from which custom scheduling systems can be built. COMPASS was written in Ada to promote readability and to conform to potential NASA Space Station Freedom standards. COMPASS has some unique characteristics that distinguishes it from commercial products. These characteristics are discussed and used to illustrate some differences between scheduling tools.

Mcmahon, Mary Beth; Fox, Barry; Culbert, Chris

1991-01-01

335

Topos, Compasses, and Triangles, Oh My!  

NSDL National Science Digital Library

In this activity, students will learn how to actually triangulate using a compass, topographical (topo) map and view of outside landmarks. It is best if a field trip to another location away from school is selected. The location should have easily discernable landmarks (like mountains or radio towers) and changes in elevation (to illustrate the topographical features) to enhance the activity. A national park is an ideal location, and visiting a number of parks, especially parks with hiking trails, is especially beneficial.

Integrated Teaching And Learning Program

336

Physics with Hadronic Probes at Compass  

Microsoft Academic Search

This paper describes the methods and goals of the spectroscopy programme of COMPASS using hadron beams, and reports on first results from a short pilot run using a 190 GeV\\/c pion beam, carried out in 2004. A partial wave analysis of the reaction pi-N --> pi-pi-pi+ N' shows significant production of a state with spin-exotic quantum numbers JPC = 1-+

Bernard Ketzer

2009-01-01

337

Quantum compass model on the square lattice  

Microsoft Academic Search

Using exact diagonalizations, Green's function Monte Carlo simulations and high-order perturbation theory, we study the low-energy properties of the two-dimensional spin- 1\\/2 compass model on the square lattice defined by the Hamiltonian H=-?r(Jxsigmarxsigmar+exx+Jzsigmarzsigmar+ezz) . When Jx!=Jz , we show that, on clusters of dimension L×L , the low-energy spectrum consists of 2L states which collapse onto each other exponentially fast

Julien Dorier; Federico Becca; Frédéric Mila

2005-01-01

338

Recent results from COMPASS muon scattering measurements  

NASA Astrophysics Data System (ADS)

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

Capozza, Luigi; COMPASS Collaboration

2012-10-01

339

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

340

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

SciTech Connect

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

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

1999-09-01

341

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.

342

Just compassion: implications for the ethics of the scarcity paradigm in clinical healthcare provision.  

PubMed

Primary care givers commonly interpret shortages of time with patients as placing them between a rock and a hard place in respect of their professional obligations to fairly distribute available healthcare resources (justice) and to offer a quality of attentive care appropriate to patients' states of personal vulnerability (compassion). The author argues that this a false and highly misleading conceptualisation of the basic structure of the ethical dilemma raised by the rationing of time in clinical settings. Drawing on an analysis of the Aristotelian virtue of nemesis, or "the sense of justice", it is argued that, far from being a moral orientation distinct from justice, compassion is a justice response insofar as it is conceptualised as a rational, appropriate response to others' adversity. The author then proceeds to point out that the perspective on justice and compassion as attributes of healthcare professionalism suggests a novel critical viewpoint on the ethics of managed forms of clinical rationing and the "scarcity paradigm" they engender: clinical conditions where primary care givers' time is intentionally rendered a commodity in chronically short supply run a deficit of justice, because they fail to make adequate accommodations for the provision of the quality of care human beings deserve in situations of illness and injury, and when they are dying. PMID:19332576

Maxwell, B

2009-04-01

343

Orientation of Magnetic Fields in Erupted Solar Filaments and Geoeffectiveness of Coronal Mass Ejections  

Microsoft Academic Search

Coronal mass ejections (CMEs) are often associated with erupted magnetic fields or disappeared chromospheric filaments. The majority of CMEs headed directly toward the earth (halo CMEs) are observed at 1AU as magnetic clouds (MC). The 3D structure of a MC can be represented by a force-free flux rope. When CMEs reach the earth, they may or may not cause magnetic

V. B. Yurchyshyn

2002-01-01

344

Crystalline orientation of alumina ceramics prepared by electrophoretic deposition under a high magnetic field  

Microsoft Academic Search

Electrophoretic deposition (EPD) of alumina in a superconducting magnet was performed at various magnetic field strengths. A stable colloidal suspension of alumina appropriate for magnetic alignment was prepared in an ethanol medium by using a phosphate ester (PE) as a dispersant. The amount of PE appropriate for the stability of the alumina suspension was investigated by measuring the pH, zeta-potential

T. Uchikoshi; T. S. Suzuki; Y. Sakka

2006-01-01

345

Magnetic characterization of noninteracting, randomly oriented, nanometer-scale ferrimagnetic particles  

Microsoft Academic Search

Studying the magnetic properties of ultrafine nanometer-scale ferrimagnetic particles (<10 nm) is vital to our understanding of superparamagnetism and its applications to environmental magnetism, biogeomagnetism, iron biomineralization, and biomedical technology. However, magnetic properties of the ultrafine nanometer-sized ferrimagnetic grains are very poorly constrained because of ambiguities caused by particle magnetostatic interactions and unknown size distributions. To resolve these problems, we

Changqian Cao; Lanxiang Tian; Qingsong Liu; Weifeng Liu; Guanjun Chen; Yongxin Pan

2010-01-01

346

Personality Traits Associated with Genetic Counselor Compassion Fatigue: The Roles of Dispositional Optimism and Locus of Control  

Microsoft Academic Search

Compassion fatigue (CMF) arises as a consequence of secondary exposure to distress and can be elevated in some health practitioners.\\u000a Locus of control and dispositional optimism are aspects of personality known to influence coping style. To investigate whether\\u000a these personality traits influence CMF risk, we surveyed 355 genetic counselors about their CMF, locus of control orientation,\\u000a and degree of dispositional

Marie C. Injeyan; Cheryl Shuman; Andrea Shugar; David Chitayat; Eshetu G. Atenafu; Amy Kaiser

347

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.

348

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

349

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.

350

Fidelity and entanglement entropy in the one-dimensional transverse-field quantum compass model  

NASA Astrophysics Data System (ADS)

The one-dimensional extended quantum compass model in the presence of a transverse magnetic field is considered. Induced effects of the transverse magnetic field on the ground state of the system are studied from the viewpoint of fidelity. Using the numerical Lanczos method, the fidelity and susceptibility of fidelity are computed in finite chains. The critical exponent of the fidelity susceptibility is obtained in good agreement with the scaling behavior of the correlation length. In addition, the von Neumann entropy is calculated and its signature on the quantum phase transition is shown.

Motamedifar, Mostafa; Mahdavifar, Saeed; Farjami Shayesteh, Saber; Nemati, Somayyeh

2013-07-01

351

Compassion, Dialogue, and Context: On Understanding the Other  

Microsoft Academic Search

This article addresses the issues of human compassion and the capacity for dialogue in clinical and socio-political contexts. Taking its cue from Martha Nussbaum's recent explorations of compassion, this work argues against the classical psychoanalytic account of human nature that is rooted in the ideas of Hobbes, Nietzsche, and Freud. Instead, a view of human sociality and analytic interaction that

Roger Frie

2010-01-01

352

The Phenomenon of Compassion Fatigue in Perioperative Nursing  

Microsoft Academic Search

Compassion fatigue is described as the emotional burden that health care providers may experience as a result of overexposure to a traumatic event that has befallen victims. Perioperative nurses are experiencing increased exposure to major traumatic events within their practice, especially those nurses who work in level I trauma centers. This article helps nurses identify risks for compassion fatigue and

Kendall Schwam

1998-01-01

353

St. Pi Day construction with a compass & ruler  

NSDL National Science Digital Library

St. Pi Day construction with compass This activity uses a compass and straight-edge(ruler) to construct a design. The design is then used to complete a worksheet involving perimeter, circumference, area and dimensional changes which affect the scale factor ratio.

Gaynr, Cheryl

2012-07-26

354

Spontaneous symmetry breaking in a generalized orbital compass model  

Microsoft Academic Search

We introduce a generalized two-dimensional orbital compass model, which interpolates continuously from the classical Ising model to the orbital compass model with frustrated quantum interactions, and investigate it using the multiscale entanglement renormalization ansatz (MERA). The results demonstrate that increasing frustration of exchange interactions triggers a second-order quantum phase transition to a degenerate symmetry broken state which minimizes one of

Lukasz Cincio; Jacek Dziarmaga; Andrzej M. Oles

2010-01-01

355

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

SciTech Connect

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

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

1988-01-01

356

Orientational dynamics of dipolar or magnetized rigid nematic liquid crystal polymers and suspensions in imposed flow and external fields  

NASA Astrophysics Data System (ADS)

In this talk, I will present a scheme for computing the exact solution of the Smoluchowski equation under imposed flow and electric or magnetic external fields for rigid nematic liquid crystal polymers. This includes a suite of mathematical theorems that reveal the intrinsic relationship among the lower order moments of the pdf and the flow as well as the external field. Then, a simple mathematical transformation links the problem to some target model problems for which the solutions can be readily obtained using the existing numerical tools. The orientational dynamics is then studied from the exact solutions of the Smoluchowski equation.

Wang, Qi

2006-03-01

357

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

SciTech Connect

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

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

1982-08-01

358

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

SciTech Connect

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

Jagadish, C.; Clapham, L.; Atherton, D.L. (Queen's Univ., Kingston, ON (Canada). Dept. of Physics)

1990-01-01

359

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

360

Compassion Fatigue Risk and Self-Care Practices among Residential Treatment Center Childcare Workers  

ERIC Educational Resources Information Center

Exploration of the presence of risk for compassion fatigue among residential childcare workers (RCW) at residential treatment facilities and the relationship between self-care practices and compassion fatigue were explored. Using the Professional Quality of Life Survey (ProQOL-R III) to assess compassion fatigue, burnout, and compassion

Eastwood, Callum D.; Ecklund, Kathryn

2008-01-01

361

Microstructure and magnetic properties of (001) oriented FePt/B4C composite films  

NASA Astrophysics Data System (ADS)

FePt/B4C multilayer composite films have been prepared by magnetron sputtering and subsequent annealing in vacuum. It was found that the B4C layers effectively serve as spacers to separate the FePt layers, enhancing (001) orientation of FePt alloy. Our results show that highly (001) oriented [Fe45Pt55(8 nm)/B4C (4 nm)]3 film with satisfactory perpendicular coercivity (4.75 kOe) has significant potential as a perpendicular recording medium.

Yang, F. J.; Wang, Hao; Wang, H. B.; Cao, X.; Yang, C. P.; Li, Q.; Zhou, M. J.; Chong, Y. M.; Zhang, W. J.

2007-11-01

362

Microstructure and magnetic properties of (001) oriented FePt/B{sub 4}C composite films  

SciTech Connect

FePt/B{sub 4}C multilayer composite films have been prepared by magnetron sputtering and subsequent annealing in vacuum. It was found that the B{sub 4}C layers effectively serve as spacers to separate the FePt layers, enhancing (001) orientation of FePt alloy. Our results show that highly (001) oriented [Fe{sub 45}Pt{sub 55}(8 nm)/B{sub 4}C (4 nm)]{sub 3} film with satisfactory perpendicular coercivity (4.75 kOe) has significant potential as a perpendicular recording medium.

Yang, F. J.; Wang Hao; Wang, H. B.; Cao, X.; Yang, C. P.; Li, Q.; Zhou, M. J.; Chong, Y. M.; Zhang, W. J. [Faculty of Physics and Electronic Technology and Key Laboratory of Ferro- and Piezo-Electric Materials and Devices, Hubei University, Wuhan 430062 (China); Department of Physics, Chinese University of Hong Kong, Hong Kong (China); Department of Physics, City University of Hong Kong, N.T. Hong Kong (China)

2007-11-15

363

Recent results from COMPASS spin program  

NASA Astrophysics Data System (ADS)

COMPASS is a fixed target experiment at CERN's Super-Proton-Synchrotron. Part of its physics program is dedicated to the spin structure of the nucleon, which it studies with a polarized muon beam and polarized targets. An overview of its recent results along this line is given. In particular, the first results of our 2011 longitudinally polarized proton run, a report on our progress towards the extraction of the gluon polarization, ? G, at NLO and an update on our measurements of transverse spin and k T -dependent processes, from our 2010 transversely polarized proton data, and of hadron multiplicities.

Bedfer, Y.

2013-11-01

364

Exact Properties of the Quantum Compass Model  

NASA Astrophysics Data System (ADS)

I show the symmetries of the compass model and spin transformations making the Hamiltonian block-diagonal. I present the new form of the Hamiltonian and explain how the diagonal blocks are related by translational symmetry and by the isotropy of interactions. I reveal the hidden symmetry of the lowest-energy block and resulting identities in four-point dimer-dimer correlators. Using exact diagonalization I show that the ground state has classical order with local quantum fluctuation vanishing in a long range and that the energy spectrum consists of discrete and continuous part.

Brzezicki, Wojciech

2011-12-01

365

Orbital Compass Model in a Checkerboard Lattice  

NASA Astrophysics Data System (ADS)

The orbital compass model in a checkerboard lattice is studied. There is a competition between the interaction for the z component of the orbital pseudo-spin along the vertical/horizontal direction and the interaction for the x component along the diagonal direction in a checkerboard lattice. In a frustration point where the two interactions compete with each other, a macroscopic number of the orbital pseudo-spin configurations are degenerated in the classical grounds state. This degeneracy is lifted by the thermal and quantum fluctuations and the z component long range order is realized. The tricritical point appears due to the coexistence of the orbital frustration and the geometrical frustration.

Nasu, Joji; Ishihara, Sumio

2011-09-01

366

Zef Damen Constructions with ruler and compass  

NSDL National Science Digital Library

A page that answers the question, What are ruler-and-compass constructions? With links to step-by-step drawings for constructions: bisecting a given angle; constructing: a line perpendicular to a given line that divides it into two equal parts; a line perpendicular to a given line passing through a given point on the line (or not on the line); the horizontal and vertical centerlines of a given circle; an equilateral triangle, given one side; an equilateral triangle inscribed in a given circle; a pentagon inscribed in a given circle; a hexagon, given one side, or inscribed in a given circle; a heptagon.

Damen, Zef

2001-01-01

367

Orientation of the DMPC unilamellar vesicle system in the magnetic field: SANS study  

Microsoft Academic Search

We present the results of a small angle neutron scattering investigation on a unilamellar DMPC vesicle system during the application of a magnetic field. The presence of the strong magnetic field, elongate the vesicles along the field and cause a change in the shape of the particles. This circumstance is caused by the presence of a small anisotropy in the

M. A. Kiselev; T. Gutberlet; A. Hoell; V. L. Aksenov; D. Lombardo

2008-01-01

368

Influence of slitting on core losses and magnetization curve of grain-oriented electrical steels  

Microsoft Academic Search

An experimental investigation was carried out by means of a single sheet and strip tester for electrical steels to find the effect of slitting on the magnetic properties of electrical strips of various widths (from 40 to 660 mm). Individual effects have been analyzed separately (slitting only, tension, and bending) regarding their influence on the deterioration of the magnetic properties

ZDENKO GODEC

1977-01-01

369

Magnetic Merging Locations Deduced from: Slow-Mode Shock Orientation Determinations, Boundary Layer Wave Intensities and Energetic Ion Velocity Dispersion in the Distant Geomagnetic Tail  

NASA Technical Reports Server (NTRS)

Several techniques will be used to determine the location of the magnetic reconnection in the distant geomagnetic tail using the ISEE-3. Techniques to be used are calculated wave-particle scattering time, plasmoid source location (if a plasmoid is found), analysis of the magnetic field geometry and slow-mode shock orientation, and examination of the magnetic field Bz components and plasma bulk speeds.

Ho, C. M.; Tsurutani, B. T.; Smith, E. J.; Murphy, N.

1995-01-01

370

Reviving a neglected celestial underwater polarization compass for aquatic animals.  

PubMed

Substantial in situ measurements on clear days in a variety of marine environments at depths in the water down to 200 m have demonstrated the ubiquitous daytime presence of sun-related e-vector (=plane of polarization) patterns. In most lines of sight the e-vectors tilt from horizontal towards the sun at angles equal to the apparent underwater refracted zenith angle of the sun. A maximum tilt-angle of approximately 48.5 degrees , is reached in horizontal lines of sight at 90 degrees to the sun's bearing (the plane of incidence). This tilt limit is set by Snell's window, when the sun is on the horizon. The biological literature since the 1980s has been pervaded with assumptions that daytime aquatic e-vectors are mainly horizontal. This review attempts to set the record straight concerning the potential use of underwater e-vectors as a visual compass and to reopen the field to productive research on aquatic animals' orientation and navigation. PMID:16271158

Waterman, Talbot H

2006-02-01

371

Characterization of circular differential selective scattering in randomly and magnetically oriented chloroplasts and light harvesting chlorophyll a/b aggregates  

SciTech Connect

Comparative circular dichroism studies were carried out in chloroplasts and the aggregated chlorophyll a/b light harvesting pigment protein complex (LHC). Much of the intense circular dichroism (CD) signal of chloroplasts and that of aggregated, isolated LHC were found to originate in circular differential light scattering (CDS). The difference spectra obtained between the CD spectra of randomly and magnetically oriented thylakoids resembled the selective light scattering spectra of chloroplasts. Furthermore, orientation-dependent changes in the CDS signal outside the principal absorbance bands were correlated with changes in the non-selective forward light scattering. These results provide evidence of a significant contribution by CDS to the CD spectrum of chloroplasts. A comparison between the CD signals of chloroplasts and aggregated LHC revealed that both preparations exhibit ''anomalous'' CD bands. The spectral shape and amplitude of these bands are changed dramatically upon magnetic alignment of the particles. These similarities are suggestive of the existence of similar helical domains in chloroplasts and the isolated LHC aggregate; hence our experimental results support the hypothesis of Faludi-Daniel and Mustardy that the LHC in the thylakoid membrane is aggregated in a liquid crystal-like structure resembling that which self-assembles in vitro. 17 refs., 4 figs.

Garab, G.; Faludi-Daniel, A.; Sutherland, J.C.; Hind, G.

1986-01-01

372

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

PubMed Central

The first demonstrations of magnetic effects on the behaviour of migratory birds and homing pigeons in laboratory and field experiments, respectively, provided evidence for the longstanding hypothesis that animals such as birds that migrate and home over long distances would benefit from possession of a magnetic sense. Subsequent identification of at least two plausible biophysical mechanisms for magnetoreception in animals, one based on biogenic magnetite and another on radical-pair biochemical reactions, led to major efforts over recent decades to test predictions of the two models, as well as efforts to understand the ultrastructure and function of the possible magnetoreceptor cells. Unfortunately, progress in understanding the magnetic sense has been challenged by: (i) the availability of a relatively small number of techniques for analysing behavioural responses to magnetic fields by animals; (ii) difficulty in achieving reproducible results using the techniques; and (iii) difficulty in development and implementation of new techniques that might bring greater experimental power. As a consequence, laboratory and field techniques used to study the magnetic sense today remain substantially unchanged, despite the huge developments in technology and instrumentation since the techniques were developed in the 1950s. New methods developed for behavioural study of the magnetic sense over the last 30 years include the use of laboratory conditioning techniques and tracking devices based on transmission of radio signals to and from satellites. Here we consider methodological developments in the study of the magnetic sense and present suggestions for increasing the reproducibility and ease of interpretation of experimental studies. We recommend that future experiments invest more effort in automating control of experiments and data capture, control of stimulation and full blinding of experiments in the rare cases where automation is impossible. We also propose new experiments to confirm whether or not animals can detect magnetic fields using the radical-pair effect together with an alternate hypothesis that may explain the dependence on light of responses by animals to magnetic field stimuli.

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

2010-01-01

373

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

NASA Astrophysics Data System (ADS)

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

Litvinenko, Yuri E.

2000-10-01

374

Diffractive Dissociation into ?-?-?+ Final States at COMPASS  

NASA Astrophysics Data System (ADS)

QCD predicts gluonic excitations like hybrids to contribute to the meson spectrum in addition to qq pair configurations. The most promising way to identify such states is the search for JPC quantum number combinations which are forbidden in the constituent quark model. The fixed target COMPASS experiment at CERN offers the opportunity to search for such states in the light quark sector with an unprecedented statistics. Diffractive reactions of 190 GeV/c pions on a lead target were studied by COMPASS during a pilot run in 2004. A Partial Wave Analysis (PWA) of the ?-?-?+ final state with 42 waves including acceptance corrections through a phase-space Monte Carlo simulation of the spectrometer was performed. The exotic ?1(1600) meson with quantum numbers JPC = 1-+ has been clearly established in the rho-pi decay channel with a mass of 1660+/-10(stat) MeV/c2 and a width of 269+/-21(stat) MeV/c2. The improved detector performance in 2008 allows us to study this channel with significantly higher statistics. First results of the ongoing analysis of the 2008 data taking period, using a 190 GeV/c pion beam on a liquid hydrogen target are presented in this paper.

Haas, Florian

2011-10-01

375

Diffractive Dissociation into ?-?-?+ Final States at COMPASS  

NASA Astrophysics Data System (ADS)

QCD predicts gluonic excitations like hybrids to contribute to the meson spectrum in addition to qq pair configurations. The most promising way to identify such states is the search for JPC quantum number combinations which are forbidden in the constituent quark model. The fixed target COMPASS experiment at CERN offers the opportunity to search for such states in the light quark sector with an unprecedented statistics. Diffractive reactions of 190 GeV/c pions on a lead target were studied by COMPASS during a pilot run in 2004. A Partial Wave Analysis (PWA) of the ?-?-?+ final state with 42 waves including acceptance corrections through a phase-space Monte Carlo simulation of the spectrometer was performed. The exotic ?1(1600) meson with quantum numbers JPC = 1-+ has been clearly established in the rho-pi decay channel with a mass of 1660+/-10(stat) MeV/c2 and a width of 269+/-21(stat) MeV/c2. The improved detector performance in 2008 allows us to study this channel with significantly higher statistics. First results of the ongoing analysis of the 2008 data taking period, using a 190 GeV/c pion beam on a liquid hydrogen target are presented in this paper.

Haas, Florian

2010-08-01

376

Grain-oriented sodium bismuth titanate-based lead-free piezoelectric ceramics prepared using the pulsed strong magnetic field and template grain growth  

NASA Astrophysics Data System (ADS)

In this paper, 0.94Bi0.5Na0.5TiO3-0.06BaTiO3 (BNBT6) lead-free piezoelectric ceramics have been prepared using the gelcasting technology. The dielectric and piezoelectric properties of these ceramics have been investigated. The specimens were sintered at 1100-1200 °C after grain-oriented under the pulsed strong magnetic field during the solidification of the green bodies. Compared with the BNBT6 samples without applying magnetic field, the ceramics textured by applying 5 T pulsed magnetic field has a coercive field with reduction of 400 V/mm, which makes the polarization process easier. Meanwhile, it is noted that the orientation degree increases with increasing sintering temperature, whereas the piezoelectric constant and electromechanical coupling coefficients are improved. If SrTiO3 seed grain is introduced, the orientation degree can reach 0.70 and the relative density of the sintered ceramics is up to 96%. The dielectric properties are anisotropic in directions vertical and parallel to the applied magnetic field. At around 180 °C, the dielectric constant in the direction vertical to the magnetic field is three times of that in the direction parallel to the magnetic field. And the dielectric loss in the direction vertical to the magnetic field is also higher than that in the direction parallel to the magnetic field.

Zhao, Jun; Wang, Fajun; Li, Wen; Li, Hui; Zhou, Dongxiang; Gong, Shuping; Hu, Yunxiang; Fu, Qiuyun

2010-10-01

377

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

NASA Astrophysics Data System (ADS)

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

Eles, Philip Thomas

378

Visualizing Magnetic Field Lines  

NSDL National Science Digital Library

In this activity, students take the age old concept of etch-a-sketch a step further. Using iron filings, students begin visualizing magnetic field lines. To do so, students use a compass to read the direction of the magnet's magnetic field. Then, students observe the behavior of iron filings near that magnet as they rotate the filings about the magnet. Finally, students study the behavior of iron filings suspended in mineral oil which displays the magnetic field in three dimensions.

VU Bioengineering RET Program, School of Engineering,

379

Molecular Dynamics Simulation of Magnetic Field Induced Orientation of Nanotube-Polymer Composite  

NASA Astrophysics Data System (ADS)

Molecular dynamics simulations are carried out to study the reorientation of single wall carbon nanotubes in a polyethylene matrix under the influence of a 25 T magnetic field. The simulations are based on a variant of velocity Verlet algorithm, which relaxes the Larmor time-step restriction while preserving second-order accuracy. Simulations reveal that the unfolding and reorganization of the polyethylene (PE) chain facilitates the reorientation of the single wall carbon nanotubes closer to the direction of the applied magnetic field. Also, they bring out the difference between the behavior of the carbon nanotubes of zigzag chirality and that of armchair chirality.

Al-Haik, Marwan S.; Hussaini, M. Yousuff

2006-11-01

380

Characterization of magnetically oriented phospholipid micelles for measurement of dipolar couplings in macromolecules  

Microsoft Academic Search

Weak alignment of solute molecules with the magnetic field can be achieved in a dilute liquid crystalline medium, consisting of an aqueous mixture of dimyristoyl-phosphatidylcholine (DMPC) and dihexanoyl- phosphatidylcholine (DHPC). For a certain range of molar ratios, DMPC and DHPC can form large, disc-shaped particles, commonly referred to as bicelles (Sanders and Schwonek, 1992), which cooperatively align in the mag-

Marcel Ottiger; Ad Bax

1998-01-01

381

Effects of Right Parietal Transcranial Magnetic Stimulation on Object Identification and Orientation Judgments  

Microsoft Academic Search

We investigated the role played by the right parietal lobe in object identification and the ability to interpret object orien- tation, using transcranial magnetic stimulation (TMS) to mo- mentarily interfere with ongoing cortical activity. Short trains of TMS pulses (12 Hz) were applied to a site overlying the right intraparietal sulcus\\/inferior parietal lobe while subjects per- formed either object identification

Irina M. Harris; Claire T. Benito; Manuela Ruzzoli; Carlo Miniussi

2008-01-01

382

The graphical treatment of magnetohydrodynamic shock waves in flows with arbitrarily oriented magnetic field  

Microsoft Academic Search

Various shock polar charts were developed in order to study magnetohydrodynamic shock configurations in plasma flows with aligned magnetic and velocity fields. It is shown that those charts (which are a natural extension of the gas dynamic shock polar diagrams of Busemann and Weise) can also be used to calculate the jumps across stationary and pseudo stationary shock waves in

M. Natter

1974-01-01

383

Spin orientation in (Ti-Mn) Ba ferrite estimated from resonant X-ray magnetic scattering  

NASA Astrophysics Data System (ADS)

Synchrotron radiation has been utilized for producing the intensity difference in resonant X-ray magnetic scattering (RXMS) of ferrimagnetic BaTiMnFe10O19 at the BL-6C beamline of the Photon Factory. The energy of incident X rays was selected as E = 7.1245 keV within the threshold region of Fe K absorption edge from the observation of X-ray magnetic circular dichroism (XMCD). An asymmetrical ratio between RXMS intensities in left- and right-handed circular polarizations makes it possible to determine the magnetic crystal structure. The residual functions of ?(?Robs - ?Rcalc)2 related to the ratio were used to evaluate magnetic moments for individual Fe sites in the least-squares calculations, refined as multiplicity parameters of atomic scattering factor. The canting angles of the spin of Fe atoms have been derived for BaTiMnFe10O19, which are 90°, 0° and 31° for octahedral 2a, 4f2 and 12k sites, respectively.

Okube, Maki; Kinoshita, Atsushi; Yoshizaki, Jumpei; Toyoda, Takeshi; Sasaki, Satoshi

2013-03-01

384

Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models  

Microsoft Academic Search

We study the magnetic interactions in Mott-Hubbard systems with partially filled t2g levels and with strong spin-orbit coupling. The latter entangles the spin and orbital spaces, and leads to a rich variety of the low energy Hamiltonians that extrapolate from the Heisenberg to a quantum compass model depending on the lattice geometry. This gives way to ``engineer'' in such Mott

G. Jackeli; G. Khaliullin

2009-01-01

385

52. Patent steering gear, hatch and steering compass binnacle, view ...  

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

52. Patent steering gear, hatch and steering compass binnacle, view from starboard looking aft. Photograph by Jet Lowe, April 1988. - Ship BALCLUTHA, 2905 Hyde Street Pier, San Francisco, San Francisco County, CA

386

Spontaneous symmetry breaking in a generalized orbital compass model  

NASA Astrophysics Data System (ADS)

We introduce a generalized two-dimensional orbital compass model, which interpolates continuously from the classical Ising model to the orbital compass model with frustrated quantum interactions, and investigate it using the multiscale entanglement renormalization ansatz (MERA). The results demonstrate that increasing frustration of exchange interactions triggers a second-order quantum phase transition to a degenerate symmetry broken state which minimizes one of the interactions in the orbital compass model. Using boson expansion within the spin-wave theory we unravel the physical mechanism of the symmetry-breaking transition as promoted by weak quantum fluctuations and explain why this transition occurs only surprisingly close to the maximally frustrated interactions of the orbital compass model. The spin waves remain gapful at the critical point, and both the boson expansion and MERA do not find any algebraically decaying spin-spin correlations in the critical ground state.

Cincio, Lukasz; Dziarmaga, Jacek; Ole?, Andrzej M.

2010-09-01

387

Homing of invasive Burmese pythons in South Florida: evidence for map and compass senses in snakes.  

PubMed

Navigational ability is a critical component of an animal's spatial ecology and may influence the invasive potential of species. Burmese pythons (Python molurus bivittatus) are apex predators invasive to South Florida. We tracked the movements of 12 adult Burmese pythons in Everglades National Park, six of which were translocated 21-36 km from their capture locations. Translocated snakes oriented movement homeward relative to the capture location, and five of six snakes returned to within 5 km of the original capture location. Translocated snakes moved straighter and faster than control snakes and displayed movement path structure indicative of oriented movement. This study provides evidence that Burmese pythons have navigational map and compass senses and has implications for predictions of spatial spread and impacts as well as our understanding of reptile cognitive abilities. PMID:24647727

Pittman, Shannon E; Hart, Kristen M; Cherkiss, Michael S; Snow, Ray W; Fujisaki, Ikuko; Smith, Brian J; Mazzotti, Frank J; Dorcas, Michael E

2014-03-01

388

The compass rose pattern in electricity prices  

NASA Astrophysics Data System (ADS)

The ``compass rose pattern'' is known to appear in the phase portraits, or scatter diagrams, of the high-frequency returns of financial series. We first show that this pattern is also present in the returns of spot electricity prices. Early researchers investigating these phenomena hoped that these patterns signaled the presence of rich dynamics, possibly chaotic or fractal in nature. Although there is a definite autoregressive and conditional heteroscedasticity structure in electricity returns, we find that after simple filtering no pattern remains. While the series is non-normal in terms of their distribution and statistical tests fail to identify significant chaos, there is evidence of fractal structures in periodic price returns when measured over the trading day. The phase diagram of the filtered returns provides a useful visual check on independence, a property necessary for pricing and trading derivatives and portfolio construction, as well as providing useful insights into the market dynamics.

Batten, Jonathan A.; Hamada, Mahmoud

2009-12-01

389

Improving Sensitivity in the NNSS COMPASS Model  

SciTech Connect

The Comprehensive Analysis of Safeguards Strategies model, COMPASS, was initially implemented with the goal of eliminating functions and requirements that did not contribute to the MC&A program at the particular site. The model sub-elements were revised several times through additions and deletions as the process was better understood. Contributions and ratings were developed and implemented. Because of the original intent, the process left the contribution factors closely grouped toward the top of the range. The effect of this is a flat sensitivity; a change in any element and sub-element affected the system effectiveness to the same degree no matter which one changed. This paper describes a method for determining element and sub-element contributions so that changes in element effectiveness are more accurately reflected in the overall system effectiveness.

Wright, J

2012-07-15

390

Enhancement of in-plane magnetic anisotropy in (111)-oriented Co0.8Fe2.2O4 thin film by deposition of PZT top layer  

NASA Astrophysics Data System (ADS)

The CoFe2O4 and Co0.8Fe2.2O4 single layer (CFO) as well as PZT/CoFe2O4 and PZT/Co0.8Fe2.2O4 bilayer thin films were grown using the pulsed laser deposition technique on Pt(111)/Si substrates at 600 °C. All films had a perfect (111)-orientation and the degree of orientation of CFO films was improved by the deposition of a PZT top layer. Precision X-ray diffraction analysis (avoiding the shift of peaks due to sample misalignment) revealed that the CFO films on Pt(111)/Si substrate were under an out-of-plane contraction and the deposition of a PZT top layer led to the increase in the out-of-plane contraction. The (111)-oriented CFO single layer films had a strong in-plane magnetic anisotropy as a result of orientation as well as the stress-induced magnetic anisotropy. The magnetic properties of CFO film were altered by the deposition of a PZT top layer leading to the enhancement of in-plane magnetic anisotropy. The enhanced in-plane magnetic anisotropy was more detectable in PZT/Co0.8Fe2.2O4 rather than PZT/CoFe2O4 bilayer film, which could be expected from its higher magnetocrystalline as well as magnetostriction constants.

Khodaei, M.; Seyyed Ebrahimi, S. A.; Park, Yong Jun; Ok, Jong Mok; Kim, Jun Sung; Son, Junwoo; Baik, Sunggi

2014-05-01

391

Hybrid Meson Structure at COMPASS Murray Moinestera, Suh Urk Chungb  

Microsoft Academic Search

Objectives and Significance: We describe a pion physics program attainable with the CERN COMPASS spectrometer, involving tracking detectors and an electromagnetic calorimeter. COMPASS can realize state- of-the-art pion beam hybrid meson and meson radiative transition studies. We review here the physics motivation for this program. We describe the beam, detector, trigger requirements, and hardware\\/software requirements for this program. The triggers

B. Sackler

392

Results on the Spin Structure of the Nucleon from COMPASS  

SciTech Connect

Highlights of the nucleon spin studies from the COMPASS experiment at CERN are presented. Three independent measurements of the gluon polarization give values compatible with zero for x close to 0.1. The quark helicity distributions are determined for all flavors. On the transversity side, Collins and Sivers asymmetries are measured for proton and deuteron targets. Plans for COMPASS-II include DVCS as well as polarized Drell-Yan measurements.

Kunne, F. [CEA Saclay IRFU/SPhN, 91191 Gif/Yvette (France)

2010-12-22

393

Results on the Spin Structure of the Nucleon from COMPASS  

NASA Astrophysics Data System (ADS)

Highlights of the nucleon spin studies from the COMPASS experiment at CERN are presented. Three independent measurements of the gluon polarization give values compatible with zero for x close to 0.1. The quark helicity distributions are determined for all flavors. On the transversity side, Collins and Sivers asymmetries are measured for proton and deuteron targets. Plans for COMPASS-II include DVCS as well as polarized Drell-Yan measurements.

Kunne, F.

2010-12-01

394

Finite temperature phase diagram of quantum compass model  

NASA Astrophysics Data System (ADS)

The quantum compass model has been proposed as a simplified model to study Mott insulators with orbital degeneracy and, more recently, as a candidate model to study protected non-local qubits. In this talk we will show that in addition to well known bond-directional ordering, there is additional ordering associated with long range string operators. We will discuss quantum Monte Carlo results that explore the thermodynamics of non-local order in the quantum compass model.

Lin, Fei; Scarola, Vito

2012-02-01

395

Utilizing Compassion Fatigue Education in Hurricanes Ivan and Katrina  

Microsoft Academic Search

Compassion Fatigue is a state that includes the symptoms of Post-Traumatic Stress Disorder. This text reviews events following\\u000a the Hurricane Ivan and Katrina disasters and how Compassion Fatigue education helped to identify and ameliorate symptoms of\\u000a the problem. I worked in a community center in the Pensacola area for one week following Ivan and in a shelter in my residential

Laura Campbell

2007-01-01

396

Optical and magnetic properties of c -oriented ZnCoO films  

NASA Astrophysics Data System (ADS)

We investigated ZnCoO thin films prepared via sol-gel methods and dip-coating techniques. The Co concentrations range from 0.5% to 5%. The films show the wurtzite crystal structure of ZnO and are highly c -axis oriented grown on the quartz substrates. They have a typical grain size of 20 to 50 nm and a thickness between 300 nm and 1 ?m. The fine structures of the Co (3d7) internal absorptions are well resolved, all zero-phonon lines (ZPL) and phonon replica related to the 4T1(F) 4A2 are observed, demonstrating the good crystalline quality of the layers and the incorporation of the Co2+ on Zn2+ lattice sites. The films show paramagnetic behaviour.

Zhou, Huijuan; Knies, Christoph; Hofmann, Detlev M.; Stehr, Jan; Volbers, Niklas; Meyer, Bruno K.; Chen, Limei; Klar, Peter; Heimbrodt, Wolfram

2006-09-01

397

Self-compassion and emotional intelligence in nurses.  

PubMed

Nurses often provide care for patients and families who are suffering and where emotions are heightened. Compassion is an essential component of the care that nurses provide. Emotions play an important role in the relationship and communication between nurses, patients and families. Self-compassion is the ability to be compassionate to oneself, without this ability nurses might not be prepared to be compassionate to patients. Emotionally intelligent persons perceive themselves as confident, better able to understand, control and manage their emotions. The purpose of this descriptive, correlational study was to examine the relationship between self-compassion and emotional intelligence. Participants were 135 nurses. The setting for this study was a health system with hospitals located in Queens, Nassau and Suffolk counties of New York, USA. Three of the hospitals in the study are located in Queens and/or the Queens/Nassau border. Queens is the most culturally diverse community in the USA. The patients served, as well as the nursing staff, are reflective of this cultural and religious diversity. Results indicated a positive correlation between self-compassion and emotional intelligence (r = 0.55). Recommendations for future research include: exploration of self-compassion and emotional intelligence in nurses, and identification of the benefits of enhancing self-compassion and emotional intelligence in nurses. PMID:20649668

Heffernan, Mary; Quinn Griffin, Mary T; Sister Rita McNulty; Fitzpatrick, Joyce J

2010-08-01

398

COMPASS 31: A Refined and Abbreviated Composite Autonomic Symptom Score  

PubMed Central

Objective To develop a concise and statistically robust instrument to assess autonomic symptoms that provides clinically relevant scores of autonomic symptom severity based on the well-established 169-item Autonomic Symptom Profile (ASP) and its validated 84-question scoring instrument, the Composite Autonomic Symptom Score (COMPASS). Patients and Methods We assessed the internal consistency of COMPASS using Cronbach ? coefficients based on the ASP of 405 healthy control subjects recruited and seen in the Mayo Clinic Autonomic Disorders Center between March 1, 1995, and March 31, 2010. Applying a simplified scoring algorithm, we then used exploratory factor analysis with orthogonal rotation and eigenvalue calculations to extract internally consistent domains and to reduce dimensionality. This analysis was followed by expert revisions to eliminate redundant content and to retain clinically important questions and final assessment of the new instrument. Results The new simplified scoring algorithm alone resulted in higher Cronbach ? values in all domains. Factor analysis revealed 7 domains with a total of 54 questions retained. Expert revisions resulted in further reduction of questions and domains with a remaining total of 31 questions in 6 domains (COMPASS 31). Measures of internal consistency were much improved compared to those for COMPASS. Following appropriate weighting, this instrument provides an autonomic symptom score from 0 to 100. Conclusion COMPASS 31 is a refined, internally consistent, and markedly abbreviated quantitative measure of autonomic symptoms. It is based on the original ASP and COMPASS, applies a much simplified scoring algorithm, and is suitable for widespread use in autonomic research and practice.

Sletten, David M.; Suarez, Guillermo A.; Low, Phillip A.; Mandrekar, Jay; Singer, Wolfgang

2012-01-01

399

Compassion Fatigue and Burnout Amongst Clinicians: A Medical Exploratory Study  

PubMed Central

Background: Compassion fatigue is a broad term comprising of two components – burnout and secondary traumatic stress. The current study is aimed at identifying ‘burnout’ and ‘compassion fatigue’ among clinicians involved in care of individuals suffering from medical illness. Materials and Methods: A total of 60 clinicians were included in the study. A semi-structured questionnaire was administered to gather information related to personal, professional, anthropometric, and metabolic profile of the study participants. Professional Quality of Life Scale (ProQoL Version V) was used to assess burnout, compassion satisfaction and secondary traumatic stress. Analysis was carried out using the SPSS version 19.0. Results: The mean age of clinicians was 46.68±11.06 (range 26-67 years). Burnout score was significantly higher in those involved in diabetology practice. Similarly, compassion satisfaction score was greater among those with greater years of practice as well as among those in private practice. Clinicians who reported a poor working condition, as opposed to good, had more burnout and less compassion satisfaction. Conclusion: The current study suggests that it is important to find out ways of decreasing burnout and compassion fatigue among clinicians.

Bhutani, Jaikrit; Bhutani, Sukriti; Balhara, Yatan Pal Singh; Kalra, Sanjay

2012-01-01

400

Mapping Magnetic Field Lines  

NSDL National Science Digital Library

This is a lesson about the magnetic field of a bar magnet. The lesson begins with an introductory discussion with learners about magnetism to draw out any misconceptions that may be in their minds. Then, learners freely experiment with bar magnets and various materials, such as paper clips, rulers, copper or aluminum wire, and pencils, to discover that magnets attract metals containing iron, nickel, and/or cobalt but not most other materials. Next, learners experiment with using a magnetic compass to discover how it is affected by the magnet and then draw the magnetic field lines of the magnet by putting dots at the location of the compass arrow. This is the first lesson in the first session of the Exploring Magnetism teacher guide.

401

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

NASA Astrophysics Data System (ADS)

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 (Ac 1) causes a marginal effect on the grain size. However, annealing in the intercritical region at temperatures between Ac 1 and Ac 3 (the ferrite+austenite to austenite transformation temperature on heating) causes rapid decarburization and development of large columnar ferrite grains free of carbide particles. This microstructure leads, after cold rolling and a fast annealing treatment, to carbide free, large ferrite grain microstructures with magnetic and mechanical properties superior to those observed typically in the same steel in the industrially fully processed condition. These results are attributed to the increment in grain size and to the {1 0 0} fiber texture developed during the final annealing at temperatures up to 850 °C. Annealing at higher temperatures, T>Ac 3, results in a strong {1 1 1} fiber texture and an increase of the quantity of second phase particles present in the microstructure, which lead to a negative effect on the final properties. The results suggest that annealing prior to cold rolling offers an attractive alternative processing route for the manufacture of fully processed low C GNO electrical steels strips.

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

2011-10-01

402

Group cohesion and organizational commitment: protective factors for nurse residents' job satisfaction, compassion fatigue, compassion satisfaction, and burnout.  

PubMed

Stress can have detrimental effects on nurse residents' levels of job satisfaction, compassion, fatigue, and burnout. This can lead to high turnover rates and poor quality of care among novice nurses. Therefore, it is critical to identify protective factors to prevent the onset of negative nurse outcomes (compassion fatigue, burnout, and job dissatisfaction) and to promote positive nurse outcomes (job satisfaction, compassion satisfaction). This study aimed to determine whether factors such as group cohesion and organizational commitment would be protective and moderate the association between stress exposure and posttraumatic stress symptoms and other negative nurse outcomes, thus facilitating positive outcomes. Findings showed that group cohesion was effective in moderating the negative effects of current stress exposure and posttraumatic stress symptoms on negative nurse outcomes, specifically on increased compassion fatigue and burnout, and reduced compassion satisfaction. In addition, organizational commitment was determined to promote positive nurse outcomes such as job satisfaction and compassion satisfaction. The study findings are promising, as retention of quality nurses is a significant problem for hospitals. Nurse managers and hospital administrators should be aware of the benefits of group cohesion and organizational commitment and strive to make the promotion of these factors a priority. PMID:24503320

Li, Angela; Early, Sean F; Mahrer, Nicole E; Klaristenfeld, Jessica L; Gold, Jeffrey I

2014-01-01

403

Magnetic reconnection in asymmetric systems: x-line orientation and guide field acceleration  

NASA Astrophysics Data System (ADS)

Magnetic reconnection in asymmetric systems has presented a number of enigmas. Beginning with the structure of the diffusion region, where nonideal electric fields, which regulate the transfer of magnetic flux from the inflow regions to the outflow regions, are often overshadowed by much larger electric fields in the vicinity, and continuing to the complex structure of the outflow regions, asymmetric reconnection has been an on-going research challenge. While MHD and Hall MHD theory and modeling has shed light into the behavior of fluid systems, kinetic physics appears to modify the dynamics substantially. In this paper, we take a new look at the kinetic structure of asymmetric, reconnecting, current sheets. The main focus of the present investigation is on both the structure of the electron diffusion region, and on the modifications to the large-scale dynamics brought about by kinetic effects. Specifically, we will analyze kinetic simulations, which indicate a preferred direction of the reconnection line, and which shed light on the question why reconnection can, at times, operate faster in the presence of a guide field than without it.

Hesse, Michael; Aunai, Nicolas; Zenitani, Seiji; Kuznetsova, Masha; Birn, Joachim

2013-04-01

404

Exploring Magnetism on Earth  

NSDL National Science Digital Library

This teacher's guide contains four lessons that provide a way for teachers to introduce students to and elaborate on Earth's changing magnetic field. It covers learning to navigate using Earth's magnetic field and compass, Earth's magnetic pole and its motion across Earth's surface, magnetic reversals on Earth, and Earth's currently declining magnetic field. These lessons have been taught primarily in math, geology, and astronomy classes.

2005-01-01

405

Orientation of littoral amphipods in two sandy beaches of Brittany (France) with wide tidal excursions  

Microsoft Academic Search

Sandhoppers orient towards the shoreline using a sun compass when they are subject to dry conditions. In this study we analysed the orientation of populations from two sandy beaches with wide tidal excursions (Brittany, France): at Damgan (sea to the South) and at Le Verger (sea to the North). At Le Verger beach Talitrus saltator was found together with Deshayesorchestia

S. Gambineri; C. Rossano; V. Durier; L. Fanini; C. Rivault; F. Scapini

2008-01-01

406

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

SciTech Connect

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

Kmety, C.R. [Department of Physics, The Ohio State University, Columbus, Ohio 43210-1106 (United States)] [Department of Physics, The Ohio State University, Columbus, Ohio 43210-1106 (United States); Manson, J.L. [Department of Chemistry, University of Utah, Salt Lake City, Utah 84112-0850 (United States)] [Department of Chemistry, University of Utah, Salt Lake City, Utah 84112-0850 (United States); Huang, Q. [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)] [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); [Department of Materials and Nuclear Engineering, University of Maryland, College Park, Maryland 20742 (United States); Lynn, J.W.; Erwin, R.W. [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)] [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Miller, J.S. [Department of Chemistry, University of Utah, Salt Lake City, Utah 84112-0850 (United States)] [Department of Chemistry, University of Utah, Salt Lake City, Utah 84112-0850 (United States); Epstein, A.J. [Department of Physics, The Ohio State University, Columbus, Ohio 43210-1106 (United States)] [Department of Physics, The Ohio State University, Columbus, Ohio 43210-1106 (United States); [Department of Chemistry, The Ohio State University, Columbus, Ohio 43210-1185 (United States)

1999-07-01

407

Quantum coherence and entanglement in the avian compass  

NASA Astrophysics Data System (ADS)

The radical-pair mechanism is one of two distinct mechanisms used to explain the navigation of birds in geomagnetic fields, however little research has been done to explore the role of quantum entanglement in this mechanism. In this paper we study the lifetime of radical-pair entanglement corresponding to the magnitude and direction of magnetic fields to show that the entanglement lasts long enough in birds to be used for navigation. We also find that the birds appear to not be able to orient themselves directly based on radical-pair entanglement due to a lack of orientation sensitivity of the entanglement in the geomagnetic field. To explore the entanglement mechanism further, we propose a model in which the hyperfine interactions are replaced by local magnetic fields of similar strength. The entanglement of the radical pair in this model lasts longer and displays an angular sensitivity in weak magnetic fields, both of which are not present in previous models.

Pauls, James A.; Zhang, Yiteng; Berman, Gennady P.; Kais, Sabre

2013-06-01

408

Quantum coherence and entanglement in the avian compass.  

PubMed

The radical-pair mechanism is one of two distinct mechanisms used to explain the navigation of birds in geomagnetic fields, however little research has been done to explore the role of quantum entanglement in this mechanism. In this paper we study the lifetime of radical-pair entanglement corresponding to the magnitude and direction of magnetic fields to show that the entanglement lasts long enough in birds to be used for navigation. We also find that the birds appear to not be able to orient themselves directly based on radical-pair entanglement due to a lack of orientation sensitivity of the entanglement in the geomagnetic field. To explore the entanglement mechanism further, we propose a model in which the hyperfine interactions are replaced by local magnetic fields of similar strength. The entanglement of the radical pair in this model lasts longer and displays an angular sensitivity in weak magnetic fields, both of which are not present in previous models. PMID:23848712

Pauls, James A; Zhang, Yiteng; Berman, Gennady P; Kais, Sabre

2013-06-01

409

Introducing minimum Fisher regularisation tomography to AXUV and soft x-ray diagnostic systems of the COMPASS tokamak  

NASA Astrophysics Data System (ADS)

The contribution focuses on plasma tomography via the minimum Fisher regularisation (MFR) algorithm applied on data from the recently commissioned tomographic diagnostics on the COMPASS tokamak. The MFR expertise is based on previous applications at Joint European Torus (JET), as exemplified in a new case study of the plasma position analyses based on JET soft x-ray (SXR) tomographic reconstruction. Subsequent application of the MFR algorithm on COMPASS data from cameras with absolute extreme ultraviolet (AXUV) photodiodes disclosed a peaked radiating region near the limiter. Moreover, its time evolution indicates transient plasma edge cooling following a radial plasma shift. In the SXR data, MFR demonstrated that a high resolution plasma positioning independent of the magnetic diagnostics would be possible provided that a proper calibration of the cameras on an x-ray source is undertaken.

Mlynar, J.; Imrisek, M.; Weinzettl, V.; Odstrcil, M.; Havlicek, J.; Janky, F.; Alper, B.; Murari, A.; JET-EFDA Contributors

2012-10-01

410

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

NASA Astrophysics Data System (ADS)

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

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

2003-08-01

411

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

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

412

Colossal anisotropic resistivity and oriented magnetic domains in strained La0.325Pr0.3Ca0.375MnO3 films  

NASA Astrophysics Data System (ADS)

Magnetic and resistive anisotropies have been studied for the La0.325Pr0.3Ca0.375MnO3 films with different thicknesses grown on low symmetric (011)-oriented (LaAlO3)0.3(SrAl0.5Ta0.5O3)0.7 substrates. In the magnetic and electronic phase separation region, a colossal anisotropic resistivity (AR) of ˜105% and an anomalous large anisotropic magnetoresistance can be observed for 30 nm film. However, for 120 nm film, the maximum AR decreases significantly (˜2 × 103%) due to strain relaxation. The colossal AR is strongly associated with the oriented formation of magnetic domains, and the features of the strain effects are believed to be useful for the design of artificial materials and devices.

Jiang, Tao; Yang, Shengwei; Zhou, Haibiao; Liu, Yukuai; Zhao, Wenbo; Feng, Lei; Hou, Yubin; Lu, Qingyou; Li, Xiaoguang

2014-05-01

413

Accelerating fibre orientation estimation from diffusion weighted magnetic resonance imaging using GPUs.  

PubMed

With the performance of central processing units (CPUs) having effectively reached a limit, parallel processing offers an alternative for applications with high computational demands. Modern graphics processing units (GPUs) are massively parallel processors that can execute simultaneously thousands of light-weight processes. In this study, we propose and implement a parallel GPU-based design of a popular method that is used for the analysis of brain magnetic resonance imaging (MRI). More specifically, we are concerned with a model-based approach for extracting tissue structural information from diffusion-weighted (DW) MRI data. DW-MRI offers, through tractography approaches, the only way to study brain structural connectivity, non-invasively and in-vivo. We parallelise the Bayesian inference framework for the ball & stick model, as it is implemented in the tractography toolbox of the popular FSL software package (University of Oxford). For our implementation, we utilise the Compute Unified Device Architecture (CUDA) programming model. We show that the parameter estimation, performed through Markov Chain Monte Carlo (MCMC), is accelerated by at least two orders of magnitude, when comparing a single GPU with the respective sequential single-core CPU version. We also illustrate similar speed-up factors (up to 120x) when comparing a multi-GPU with a multi-CPU implementation. PMID:23658616

Hernández, Moisés; Guerrero, Ginés D; Cecilia, José M; García, José M; Inuggi, Alberto; Jbabdi, Saad; Behrens, Timothy E J; Sotiropoulos, Stamatios N

2013-01-01

414

Accelerating Fibre Orientation Estimation from Diffusion Weighted Magnetic Resonance Imaging Using GPUs  

PubMed Central

With the performance of central processing units (CPUs) having effectively reached a limit, parallel processing offers an alternative for applications with high computational demands. Modern graphics processing units (GPUs) are massively parallel processors that can execute simultaneously thousands of light-weight processes. In this study, we propose and implement a parallel GPU-based design of a popular method that is used for the analysis of brain magnetic resonance imaging (MRI). More specifically, we are concerned with a model-based approach for extracting tissue structural information from diffusion-weighted (DW) MRI data. DW-MRI offers, through tractography approaches, the only way to study brain structural connectivity, non-invasively and in-vivo. We parallelise the Bayesian inference framework for the ball & stick model, as it is implemented in the tractography toolbox of the popular FSL software package (University of Oxford). For our implementation, we utilise the Compute Unified Device Architecture (CUDA) programming model. We show that the parameter estimation, performed through Markov Chain Monte Carlo (MCMC), is accelerated by at least two orders of magnitude, when comparing a single GPU with the respective sequential single-core CPU version. We also illustrate similar speed-up factors (up to 120x) when comparing a multi-GPU with a multi-CPU implementation.

Hernandez, Moises; Guerrero, Gines D.; Cecilia, Jose M.; Garcia, Jose M.; Inuggi, Alberto; Jbabdi, Saad; Behrens, Timothy E. J.; Sotiropoulos, Stamatios N.

2013-01-01

415

Self-compassion and Psychological Resilience Among Adolescents and Young Adults  

Microsoft Academic Search

Self-compassion is an adaptive way of relating to the self when considering personal inadequacies or difficult life circumstances. However, prior research has only examined self-compassion among adults. The current study examined self-compassion among adolescents (N = 235; Mage = 15.2) and included a sample of young adults as a comparison group (N = 287; Mage = 21.1). Results indicated that self-compassion was strongly associated with well-being among adolescents

Kristin D. Neff; Pittman McGehee

2010-01-01

416

Self-Compassion Versus Global Self-Esteem: Two Different Ways of Relating to Oneself  

Microsoft Academic Search

This research examined self-compassion and self-esteem as they relate to various aspects of psychological functioning. Self- compassion entails treating oneself with kindness, recognizing one's shared humanity, and being mindful when considering negative aspects of oneself. Study 1 (N 5 2,187) compared self-compassion and global self-esteem as they relate to ego-focused reactivity. It was found that self-compassion predicted more stable feelings

Kristin D. Neff; Roos Vonk

2009-01-01

417

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

SciTech Connect

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

Gilbert, Dustin A.; Liu, Kai [Physics Department, University of California, Davis, California 95616 (United States)] [Physics Department, University of California, Davis, California 95616 (United States); Wang, Liang-Wei; Lai, Chih-Huang [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan (China)] [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan (China); Klemmer, Timothy J.; Thiele, Jan-Ulrich [Seagate Technology, Fremont, California 94538 (United States)] [Seagate Technology, Fremont, California 94538 (United States)

2013-04-01

418

Recent COMPASS results on the gluon polarization  

SciTech Connect

The spin structure of the nucleon is studied in the COMPASS experiment at CERN/SPS, from the collisions of 160 GeV polarized muon beam with a {sup 6}LiD target. The data collected from 2002 to 2006 provide an accurate measurement of longitudinal double spin cross-section asymmetries. The latest results on the gluon polarization, accessed from two independent analyses of photon-gluon fusion selected events, are presented. The study of the open-charm production allows to extract the gluon polarization (in LO QCD) from the measurement of the asymmetry, the value obtained being {delta}g/g -0.49{+-}0.27(stat){+-}0.11(syst), at an average x{sub g} 0.11{sub -0.05}{sup +0.11} and a scale <{mu}{sup 2}> = 13(GeV/c){sup 2}. An alternative and independent way to study the gluon polarization, by studying the high transverse momentum hadron pairs produced, leads to a value {delta}g/g 0.08{+-}0.10(stat){+-}0.05(syst), at x{sub g}{sup a{nu}} 0.082{sub -0.027}{sup +0.041} and <{mu}{sup 2}> = 3(GeV/c){sup 2}.

Quintans, Catarina [Laboratorio de Instrumentacao e Fisica Experimental de Particulas, LIP-Lisboa (Portugal)

2009-03-23

419

Quantum compass model on the square lattice  

NASA Astrophysics Data System (ADS)

Using exact diagonalizations, Green’s function Monte Carlo simulations and high-order perturbation theory, we study the low-energy properties of the two-dimensional spin- 1/2 compass model on the square lattice defined by the Hamiltonian H=-?r(Jx?rx?r+exx+Jz?rz?r+ezz) . When Jx?Jz , we show that, on clusters of dimension L×L , the low-energy spectrum consists of 2L states which collapse onto each other exponentially fast with L , a conclusion that remains true arbitrarily close to Jx=Jz . At that point, we show that an even larger number of states collapse exponentially fast with L onto the ground state, and we present numerical evidence that this number is precisely 2×2L . We also extend the symmetry analysis of the model to arbitrary spins and show that the twofold degeneracy of all eigenstates remains true for arbitrary half-integer spins but does not apply to integer spins, in which cases the eigenstates are generically nondegenerate, a result confirmed by exact diagonalizations in the spin-1 case. Implications for Mott insulators and Josephson junction arrays are briefly discussed.

Dorier, Julien; Becca, Federico; Mila, Frédéric

2005-07-01

420

The Development and Evaluation of a Compassion Scale  

PubMed Central

Compassion is the capacity for being moved by the suffering of others and wanting to help alleviate it. Compassion may mediate the health benefits and hazards of social networks and relationships. The monitoring and management of the level of compassion across social networks and relationships may be critical to the preservation of the health benefits and the prevention of the health hazards of social networks and relationships. We developed a 10-item self-report measure of compassion and evaluated its psychometric properties among 310 respondents drawn from the University and its surrounding communities. The mean total score was 3.62 (SD=1.09). The item-to-total correlations ranged from 0.50-0.71. The mean inter-item correlation was 0.33. The internal consistency was 0.82. The scale correlated well with the Sprecher and Fehr's Compassionate Love Scale (r=0.66; p=.000). Two method factors measuring the same construct explained 57% of the variance in the sample. The scale is user-friendly, easy to score, and characterized by good psychometric properties. It can be used to foster the understanding of the impact of the level of compassion on disease occurrence and outcomes across social networks and relationships.

Martins, David; Nicholas, Nichole A.; Shaheen, Magda; Jones, Loretta; Norris, Keith

2013-01-01

421

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

Microsoft Academic Search

The chemical compass model, based on radical pair reactions, is a fascinating idea to explain avian magnetoreception. At present, questions concerning the key ingredients responsible for the high sensitivity of a chemical compass and the possible role of quantum coherence and decoherence remain unsolved. Here, we investigate the optimized hyperfine coupling for a chemical compass in order to achieve the

Jianming Cai; Filippo Caruso; Martin B. Plenio

2011-01-01

422

Is compassion possible in a market-led NHS?  

PubMed

The principle of compassionate care is increasingly seen as the core element of good nursing practice. However, recent media reports have focused on the "compassion deficit". We carried out a review of national and international evidence on core professional values, which showed that caring and compassion are inherent nursing values. While the development of these values is influenced by training and role modelling, the main influence is the organisation and culture in which nurses work. This article discusses the findings of the review in relation to the national debate around compassionate care within an NHS that is being fundamentally changed. We suggest any failure in compassion is more likely to be due to government health policy and NHS organisational culture than to any shortcomings of nurses or nursing practice. PMID:23513933

Flynn, Maria; Mercer, Dave

423

COMPASS results on collins and sivers asymmetries for charged hadrons  

NASA Astrophysics Data System (ADS)

The study of transverse spin and transverse momentum effects is an important part of the scientific program of COMPASS, a fixed target experiment at the CERN SPS taking data since 2002. The studies are carried on by measuring the hadrons produced in deep inelastic scattering (DIS) of 160 GeV/ c muons off different targets. Among the possible asymmetries in the hadron azimuthal distributions, particularly interesting are the Collins and Sivers asymmetries which the COMPASS Collaboration has measured using transversely polarised deuteron and proton targets. Here new results for charged pions and kaons obtained from the 2010 run with a transversely polarised proton target are presented for the first time.

Martin, Anna

2014-01-01

424

Quantum phase transition in the one-dimensional compass model  

NASA Astrophysics Data System (ADS)

We introduce a one-dimensional model which interpolates between the Ising model and the quantum compass model with frustrated pseudospin interactions ?iz?i+1z and ?ix?i+1x , alternating between even and/or odd bonds, and present its exact solution by mapping to quantum Ising models. We show that the nearest-neighbor pseudospin correlations change discontinuously and indicate divergent correlation length at the first-order quantum phase transition. At this transition, one finds the disordered ground state of the compass model with high degeneracy 2×2N/2 in the limit of N?? .

Brzezicki, Wojciech; Dziarmaga, Jacek; Ole?, Andrzej M.

2007-04-01

425

Re-examining the directional-ordering transition in the compass model with screw-periodic boundary conditions  

NASA Astrophysics Data System (ADS)

We study the directional-ordering transition in the two-dimensional classical and quantum compass models on the square lattice by means of Monte Carlo simulations. An improved algorithm is presented which builds on the Wolff cluster algorithm in one-dimensional subspaces of the configuration space. This improvement allows us to study classical systems up to L=512 . Based on this algorithm, we give evidence for the presence of strongly anomalous scaling for periodic boundary conditions which is much worse than anticipated before. We propose and study alternative boundary conditions for the compass model which do not make use of extended configuration spaces and show that they completely remove the problem with finite-size scaling. In the last part, we apply these boundary conditions to the quantum problem and present a considerably improved estimate for the critical temperature which should be of interest for future studies on the compass model. Our investigation identifies a strong one-dimensional magnetic ordering tendency with a large correlation length as the cause of the unusual scaling and moreover allows for a precise quantification of the anomalous length scale involved.

Wenzel, Sandro; Janke, Wolfhard; Läuchli, Andreas M.

2010-06-01

426

Re-examining the directional-ordering transition in the compass model with screw-periodic boundary conditions.  

PubMed

We study the directional-ordering transition in the two-dimensional classical and quantum compass models on the square lattice by means of Monte Carlo simulations. An improved algorithm is presented which builds on the Wolff cluster algorithm in one-dimensional subspaces of the configuration space. This improvement allows us to study classical systems up to L=512. Based on this algorithm, we give evidence for the presence of strongly anomalous scaling for periodic boundary conditions which is much worse than anticipated before. We propose and study alternative boundary conditions for the compass model which do not make use of extended configuration spaces and show that they completely remove the problem with finite-size scaling. In the last part, we apply these boundary conditions to the quantum problem and present a considerably improved estimate for the critical temperature which should be of interest for future studies on the compass model. Our investigation identifies a strong one-dimensional magnetic ordering tendency with a large correlation length as the cause of the unusual scaling and moreover allows for a precise quantification of the anomalous length scale involved. PMID:20866539

Wenzel, Sandro; Janke, Wolfhard; Läuchli, Andreas M

2010-06-01

427

Effects of deposition temperature and in-situ annealing time on structure and magnetic properties of (001) orientation FePt films  

NASA Astrophysics Data System (ADS)

FePt films were prepared on (100) oriented single crystal MgO substrates at high temperature ranging from 620 until 800 °C and in-situ annealed for different times ranging from 0 to 60 min to obtain ordered FePt films. The structural analysis indicates that FePt films grow epitaxially on MgO (100) substrates. Both increasing deposition temperature and in-situ annealing time enhance the (001) texture and ordering of FePt films. The magnetic analysis shows that these L10 FePt films have perpendicular anisotropy and the easy magnetization c-axis is perpendicular to the film plane. Magnetization reversal is controlled by a rotational mechanism. The hard magnetic properties of the films are improved with increasing deposition temperature or in-situ annealing time.

Yu, Yongsheng; George, T. A.; Li, Haibo; Sun, Daqian; Ren, Zhenan; Sellmyer, D. J.

2013-02-01

428

Magnetic phase transitions and bulk spin-valve effect tuned by in-plane field orientation in Ca3Ru2O7  

NASA Astrophysics Data System (ADS)

We have performed systematic in-plane angle-dependent c-axis transverse magnetotransport measurements on the double-layered ruthenate Ca3Ru2O7 throughout a broad field and temperature range. Our results reveal that the magnetic states unusually evolve with in-plane rotation of magnetic field. When magnetic field is applied along the b axis, we probe crossover magnetic states in close proximity to phase boundaries of long-range ordered antiferromagnetic states. These crossover magnetic states are characterized by short-range antiferromagnetic order and switch to polarized paramagnetic states at critical angles as the in-plane field is rotated from the b to the a axis. Additionally, we observe bulk spin-valve behavior resulting from spin-flop transitions tuned by in-plane rotation of magnetic field. Our results highlight the complex nature of the spin-charge coupling in Ca3Ru2O7 and posts a challenging question: why does the change of magnetic-field orientation result in magnetic phase transitions.

Fobes, D.; Peng, J.; Qu, Z.; Liu, T. J.; Mao, Z. Q.

2011-07-01

429

Electronic anisotropy, magnetic field-temperature phase diagram and their dependence on resistivity in c-axis oriented MgB2 thin films  

Microsoft Academic Search

An important predicted, but so far uncharacterized, property of the new superconductor MgB2 is electronic anisotropy arising from its layered crystal structure. Here we report on three c-axis oriented thin films, showing that the upper critical field anisotropy ratio Hc2||\\/Hc2? is 1.8 to 2.0, the ratio increasing with higher resistivity. Measurements of the magnetic field-temperature phase diagram show that flux

S. Patnaik; L. D. Cooley; A. Gurevich; A. A. Polyanskii; J. Jiang; X. Y. Cai; A. A. Squitieri; M. T. Naus; M. K. Lee; J. H. Choi; L. Belenky; S. D. Bu; J. Letteri; X. Song; D. G. Schlom; S. E. Babcock; C. B. Eom; E. E. Hellstrom; D. C. Larbalestier

2001-01-01

430

Magnetic Resonance Studies of Half-Metallic Epitaxial CrO 2 Thin Films Grown on Differently Oriented TiO 2 Substrates  

Microsoft Academic Search

The results of structural and ferromagnetic resonance (FMR) investigations of epitaxial half- metallic chromium dioxide (CrO2) thin films of thicknesses between 58 nm and 540 nm grown by chemical vapor deposition (CVD) on (100) and (110)-oriented\\u000a TiO2 single crystal substrates are presented. The angular dependences of the FMR spectra in different experimental geometries\\u000a were obtained. Effective magnetic anisotropies of epitaxially grown CrO2

A. Intepe; S. Kazan; K. B. Chetry; F. Mikailzade; R. Yilgin; B. Akta?; M. Ozdemir; A. Gupta

431

Dung beetles ignore landmarks for straight-line orientation.  

PubMed

Upon locating a suitable dung pile, ball-rolling dung beetles shape a piece of dung into a ball and roll it away in a straight line. This guarantees that they will not return to the dung pile, where they risk having their ball stolen by other beetles. Dung beetles are known to use celestial compass cues such as the sun, the moon and the pattern of polarised light formed around these light sources to roll their balls of dung along straight paths. Here, we investigate whether terrestrial landmarks have any influence on straight-line orientation in dung beetles. We find that the removal or re-arrangement of landmarks has no effect on the beetle's orientation precision. Celestial compass cues dominate straight-line orientation in dung beetles so strongly that, under heavily overcast conditions or when prevented from seeing the sky, the beetles can no longer orient along straight paths. To our knowledge, this is the only animal with a visual compass system that ignores the extra orientation precision that landmarks can offer. PMID:23076443

Dacke, Marie; Byrne, Marcus; Smolka, Jochen; Warrant, Eric; Baird, Emily

2013-01-01

432

A high accuracy magnetic heading system composed of fluxgate magnetometers and a microcomputer  

Microsoft Academic Search

The authors present a magnetic heading system consisting of two fluxgate magnetometers and a single-chip microcomputer. The system, when compared to gyro compasses, is smaller in size, lighter in weight, simpler in construction, quicker in reaction time, free from drift, and more reliable. Using a microcomputer in the system, heading error due to compass deviation, sensor offsets. scale factor uncertainty,

Sheng-Wu Liu; Zhao-Nian Zhang; J. C. Hung

1989-01-01

433

Animal Magnetism  

NSDL National Science Digital Library

This radio broadcast looks at the mysterious way in which certain animals can travel vast distances around the planet, using the magnetic field of Earth to guide them. Migrating birds, fish, sea turtles, honey bees and even bacteria have all been found to navigate using the magnetic field of Earth, sometimes over quite enormous distances and reaching targets of only a few degrees in width. There is discussion about where magnetic receptors may be within animals and that particular cells in migratory creatures contain magnetite, a substance which humans used many hundreds of years ago to create the first compass. This radio broadcast discusses animal magnetism with researchers who have been working with sea turtles, to discover just how the turtles find their way back to the same beaches every year to lay their eggs. There is explanation of how the magnetic sense in animals has two components: acting as a compass to guide them and providing them with location; and how this seems to be possible since the magnetic field gets stronger in higher latitudes and inclination angle (the angle of the magnetic field to the surface of Earth) changes over different points on Earth. The broadcast also explains why creatures such as honey bees and even bacteria need to be in tune with the magnetic field of Earth, and how magnetic sense is prevalent in many animals with seemingly no need for it. The broadcast is 29 minutes in length.

434

Control of fault shearing on the fabric of a syn-tectonic granite : magnetic fabric and crystallographic preferred orientation (CPO) of quartz input  

NASA Astrophysics Data System (ADS)

The late-Miocene monzogranitic pluton of Porto Azzurro (PA) on Elba Island (Italy), was emplaced in the footwall of the N-S striking Zuccale Fault (ZF), a Low-Angle Normal Fault (LANF). In the Barbarossa outcrop, this poorly exposed pluton shows few NNE-SSW and WNW-ESE striking shear bands, respectively moderately dipping eastward and steeply dipping northward, which appear to be associated to the brittle fracturation, and no clear relationship between all these structures and the ZF is described. In order to get information about possible relationship between these shear bands, brittle structures and prior fabric of this igneous stock, and about the timing of formation of these ductile deformations relative to the pluton emplacement, rock fabrics were studied on samples taken both inside and outside of one of these shear bands. The magnetic fabric was analyzed with anisotropy of magnetic susceptibility measurements (AMS), and the crystallographic preferred orientations of dynamically recrystallized quartz were measured with the electron back-scattered diffraction (EBSD) method. Quartz CPOs are directly compared, after EBSD data processing, with the macroscopic ductile structures orientation, according to the geographical North. The pooling of data of these two methods reveals two distinct petrofabrics within the Barbarossa monzogranite. The first fabric, with a low dip angle, is identified only on samples taken outside of the influence of the shear bands. Orientation of paramagnetic minerals, with biotite as the main magnetic mineral carrier, and quartz CPOs are consistent, pervasive within the whole outcrop and are linked to the eastward extension produced by the LANF Zuccale Fault. This fabric suggests that the dynamic of the magmatic supplies during emplacement of the pluton of PA was controlled by the LANF's extension, and confirms this magmatic intrusion to be likely syn-tectonic. The second fabric is identified close or within the studied shear bands with a similar orientation to them. Our data show that these ductile structures impose a local new tectonic fabric overprinting the pre-existing one. The common re-orientation of the magnetic minerals, of the recrystallized quartz and of the brittle structures suggest a strain localization and a continuous strain process localized along stain bands from late-magmatic flowing, highlighted by biotite orientation, then during shear bands activation, at temperature around 350-400° C. Finally, these structures would have remained active through the ductile-brittle transition, leading to the localized intense fracturation of the Barbarossa outcrop.

Walter, Bastien; Géraud, Yves; Diraison, Marc; Oliot, Emilien

2013-04-01

435

Emergency Department Nurses' Lived Experience with Compassion Fatigue  

Microsoft Academic Search

The profession of nursing is in the midst of a crisis brought on by a nursing shortage. Many are choosing to leave the profession of nursing coupled with fewer numbers choosing nursing as a profession. As a result, nurses are challenged with increased acuity of patient care in the face of short staffing. Compassion fatigue can result from these highly

Michelle Marie Chase

2005-01-01

436

Mechanism of hole propagation in the orbital compass models  

NASA Astrophysics Data System (ADS)

We explore the propagation of a single hole in the quantum compass model, whose nematic ground state is given by mutually decoupled antiferromagnetic chains. The compass model can be seen as the strong-coupling limit of a spinless two-band Hubbard model, which we study here using mean-field theory and the variational cluster approach. Due to the symmetries of the compass model, the inherent disorder along one lattice direction turns out not to affect hole motion, and doping a hole consequently does not lift the subextensive degeneracy of the nematic phase. To broaden and deepen understanding, we derive a generalized itinerant model and address the transition to two-dimensional Ising order. We observe coherent hole motion in both the nematic and the antiferromagnetic phases, also in the presence of quantum fluctuations away from pure Ising exchange. In addition to quantum fluctuations and interorbital hopping, three-site hopping is found to play an important role and to dominate propagation in the two-dimensional Ising limit as well as along the antiferromagnetic chains in the nematic order which forms in the compass model.

Brzezicki, Wojciech; Daghofer, Maria; Ole?, Andrzej M.

2014-01-01

437

EDICAM fast video diagnostic installation on the COMPASS tokamak  

Microsoft Academic Search

A new camera system ‘event detection intelligent camera’ (EDICAM) is being developed by the Hungarian Association and has been installed on the COMPASS tokamak in the Institute of Plasma Physics AS CR in Prague, during February 2009. The standalone system contains a data acquisition PC and a prototype sensor module of EDICAM. Appropriate optical system have been designed and adjusted

A. Szappanos; M. Berta; M. Hron; R. Pánek; J. Stöckel; S. Tulipán; G. Veres; V. Weinzettl; S. Zoletnik

2010-01-01

438

Quantum Correlation in One-dimensional Extend Quantum Compass Model  

Microsoft Academic Search

We study the quantum correlations in one-dimensional extended quantum compass model. 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.

Wen-Long You

2011-01-01

439

Diffractive Dissociation into {sup --+} Final States at COMPASS  

Microsoft Academic Search

QCD predicts gluonic excitations like hybrids to contribute to the meson spectrum in addition to qq-bar pair configurations. The most promising way to identify such states is the search for J{sup PC} quantum number combinations which are forbidden in the constituent quark model. The fixed target COMPASS experiment at CERN offers the opportunity to search for such states in the

Haas; Florian

2010-01-01

440

The nature of quantum phase transition in quantum compass model  

Microsoft Academic Search

In this work, we show that the quantum compass model in two dimension can be mapped to a fermionic model with local density interaction and the quantum phase transition point at the symmetric point Jx=Jz marks a first order phase transition.

Han-Dong Chen; Chen Fang; Jiangping Hu; Hong Yao

2006-01-01

441

Discovering the Dilaton particle with the Cosmic Compass experiment  

Microsoft Academic Search

The cosmic compass experiment measures the one-way group velocity of light. It also measures a Morse function critical point that is modeled as a bulk dilaton caustic in Anti de Sitter (AdS) spacetime under the strong Maldacena conjecture. And it also measures the renormalization length exponent showing that dilaton gravity is strong at the Planck scale but decouples at low

George Soli

2006-01-01

442

The nature of quantum phase transition in quantum compass model  

NASA Astrophysics Data System (ADS)

In this work, we show that the quantum compass model in two dimension can be mapped to a fermionic model with local density interaction and the quantum phase transition point at the symmetric point Jx=Jz marks a first order phase transition.

Chen, Han-Dong; Fang, Chen; Hu, Jiangping; Yao, Hong

2006-03-01

443