729 research outputs found
Magnetoresistance Anisotropy of Polycrystalline Cobalt Films: Geometrical-Size- and Domain-Effects
The magnetoresistance (MR) of 10 nm to 200 nm thin polycrystalline Co-films,
deposited on glass and insulating Si(100), is studied in fields up to 120 kOe,
aligned along the three principal directions with respect to the current:
longitudinal, transverse (in-plane), and polar (out-of-plane). At technical
saturation, the anisotropic MR (AMR) in polar fields turns out to be up to
twice as large as in transverse fields, which resembles the yet unexplained
geometrical size-effect (GSE), previously reported for Ni- and Permalloy films.
Upon increasing temperature, the polar and transverse AMR's are reduced by
phonon-mediated sd-scattering, but their ratio, i.e. the GSE remains unchanged.
Basing on Potters's theory [Phys.Rev.B 10, 4626(1974)], we associate the GSE
with an anisotropic effect of the spin-orbit interaction on the sd-scattering
of the minority spins due to a film texture. Below magnetic saturation, the
magnitudes and signs of all three MR's depend significantly on the domain
structures depicted by magnetic force microscopy. Based on hysteresis loops and
taking into account the GSE within an effective medium approach, the three MR's
are explained by the different magnetization processes in the domain states.
These reveal the importance of in-plane uniaxial anisotropy and out-of-plane
texture for the thinnest and thickest films, respectively.Comment: 10 pages, 9 figure
Plasma catecholamines and social behavior in male vervet monkeys (Cercopithecus aethiops sabaeus)
Many investigations in humans indicate that epinephrine, norepinephrine and their ratio may correlate with such traits as social competence, academic achievement, and aggression. However, the socioeconomic, dietary, and environmental confounds accompanying most human studies complicate their interpretation. Social status, aggression, and other social behaviors can be reliably assessed in nonhuman primates under conditions controlling for crucial environmental factors. If interpretation of human studies is correct, dominant and subordinate male vervet monkeys should exhibit distinctive patterns of catecholamine secretion. To test this possibility, seventeen adult male monkeys living in six stable social groups were observed for 6 months. Based on their success in agonistic events, subjects were categorized as dominant or subordinate. Alpha scores were calculated from empirically derived factors to provide a noncategorical measure of dominant behavioral style. Plasma epinephrine and norepinephrine samples obtained from anesthetized subjects did not differ between dominant and subordinate males. Alpha scores, however, distinguished high from low norepinephrine/epinephrine ratio groups. These findings are consistent with studies in humans linking high epinephrine, low norepinephrine, and social competence.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30093/1/0000465.pd
Platelet‐Derived Growth Factor Promotes Periodontal Regeneration in Localized Osseous Defects: 36‐Month Extension Results From a Randomized, Controlled, Double‐Masked Clinical Trial
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141092/1/jper0456.pd
Living Cellular Construct for Increasing the Width of Keratinized Gingiva: Results From a Randomized, Within‐Patient, Controlled Trial
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142206/1/jper1414.pd
On the biological and genetic diversity in Neospora caninum
Published: 22 March 2010Neospora caninum is a parasite regarded a major cause of foetal loss in cattle. A key requirement to an understanding of the epidemiology and pathogenicity of N. caninum is knowledge of the biological characteristics of the species and the genetic diversity within it. Due to the broad intermediate host range of the species, worldwide geographical distribution and its capacity for sexual reproduction, significant biological and genetic differences might be expected to exist. N. caninum has now been isolated from a variety of different host species including dogs and cattle. Although isolates of this parasite show only minor differences in ultrastructure, considerable differences have been reported in pathogenicity using mainly mouse models. At the DNA level, marked levels of polymorphism between isolates were detected in mini- and microsatellites found in the genome of N. caninum. Knowledge of what drives the biological differences that have been observed between the various isolates at the molecular level is crucial in aiding our understanding of the epidemiology of this parasite and, in turn, the development of efficacious strategies, such as live vaccines, for controlling its impact. The purpose of this review is to document and discuss for the first time, the nature of the diversity found within the species Neospora caninum.Sarwat E. Al-Qassab, Michael P. Reichel and John T. Elli
Flexible Supervised Autonomy for Exploration in Subterranean Environments
While the capabilities of autonomous systems have been steadily improving in
recent years, these systems still struggle to rapidly explore previously
unknown environments without the aid of GPS-assisted navigation. The DARPA
Subterranean (SubT) Challenge aimed to fast track the development of autonomous
exploration systems by evaluating their performance in real-world underground
search-and-rescue scenarios. Subterranean environments present a plethora of
challenges for robotic systems, such as limited communications, complex
topology, visually-degraded sensing, and harsh terrain. The presented solution
enables long-term autonomy with minimal human supervision by combining a
powerful and independent single-agent autonomy stack, with higher level mission
management operating over a flexible mesh network. The autonomy suite deployed
on quadruped and wheeled robots was fully independent, freeing the human
supervision to loosely supervise the mission and make high-impact strategic
decisions. We also discuss lessons learned from fielding our system at the SubT
Final Event, relating to vehicle versatility, system adaptability, and
re-configurable communications.Comment: Field Robotics special issue: DARPA Subterranean Challenge,
Advancement and Lessons Learned from the Final
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