1,978 research outputs found
Nanoengineered Curie Temperature in Laterally-Patterned Ferromagnetic Semiconductor Heterostructures
We demonstrate the manipulation of the Curie temperature of buried layers of
the ferromagnetic semiconductor (Ga,Mn)As using nanolithography to enhance the
effect of annealing. Patterning the GaAs-capped ferromagnetic layers into
nanowires exposes free surfaces at the sidewalls of the patterned (Ga,Mn)As
layers and thus allows the removal of Mn interstitials using annealing. This
leads to an enhanced Curie temperature and reduced resistivity compared to
unpatterned samples. For a fixed annealing time, the enhancement of the Curie
temperature is larger for narrower nanowires.Comment: Submitted to Applied Physics Letters (minor corrections
Genetic analysis of cognitive failures (CFQ); A study of Dutch adolescent twins and their parents
A substantial part of the inter-individual variation in everyday cognitive failures in memory, perception and motor control can be attributed to genetic factors. Cognitive failures were assessed with the Cognitive Failures Questionnaire (Broadbent, Cooper, FitzGerald and Parkes, 1982) in a large sample of Dutch adolescent twin pairs and their biological parents. The heritability for CFQ scores was around 50 per cent. There was no association between CFQ scores and age or educational level. Both in the parental generation (aged 46 years on average) and in the o€spring generation (aged 17.7 years on average) women had somewhat higher mean CFQ scores than men. There were no sex di€erences in heritabilities. The part of the variance that could not be attributed to genetic factors was best explained by environmental in¯uences unique to the individual. There was no evidence for the in¯uence of shared environment on CFQ scores. CFQ scores of husband and wife were correlated (r ˆ 0.22) and this association was modeled as phenotypic assortment. The correlations between parents and o€spring were somewhat lower than the correlations between dizygotic twins. Under a model with equal heritabilities in parents and o€spring, there was some evidence that the genetic factors that in¯uence cognitive failures in the two generations are partly di€erent. # 1998 John Wiley & Sons, Ltd
Equation of state for -stable hot nuclear matter
We provide an equation of state for hot nuclear matter in -equilibrium
by applying a momentum-dependent effective interaction. We focus on the study
of the equation of state of high-density and high-temperature nuclear matter,
containing leptons (electrons and muons) under the chemical equilibrium
condition in which neutrinos have left the system. The conditions of charge
neutrality and equilibrium under -decay process lead first to the
evaluation of proton and lepton fractions and afterwards of internal energy,
free energy, pressure and in total to the equation of state of hot nuclear
matter. Thermal effects on the properties and equation of state of nuclear
matter are assesed and analyzed in the framework of the proposed effective
interaction model. Special attention is dedicated to the study of the
contribution of the components of -stable nuclear matter to the entropy
per particle, a quantity of great interest for the study of structure and
collapse of supernova.Comment: 28 pages, 18 figure
Faculty Senates and College Presidents: Perspectives on Collaborations
Colleges and universities have historically provided faculty members access to sharing authority, and this has been manifest in recent decades through the creation and use of a formal body called a faculty senate. These formal bodies have at times been highly effective at articulating faculty member interests, yet there are few formal definitions or boundaries concerning what areas senates are most appropriately engaged. College presidents similarly recognize that senates have a role in institutional decision-making, yet often lack a clear understanding of where and how they should be engaged. The current study explored faculty senate leader and college president perceptions of boundaries of senate collaboration in decision-making. Survey respondents identified a high level of agreement that faculty senates should be engaged in academic collaboration with the president, but there was less agreement concerning collaboration in areas of campus life and work-life
Changes in magnetic scattering anisotropy at a ferromagnetic/superconducting interface
We show that some metals and alloys (X = Cu, Ag, FeMn, or Cu and Ag combined
with each other), sputtered between ferromagnetic Co and superconducting Nb,
produce no change in current-perpendicular-to-plane magnetoresistance (CPP-MR)
in a carefully designed CPP-spin-valve. In contrast, other metals (Ru or Au) or
combinations (Cu or Ag combined with Au, Ru, or FeMn) change the CPP-MR, in
some cases even reversing its sign. We ascribe these changes to activation of
magnetic scattering anisotropies at a ferromagnetic/superconducting interface,
apparently by strong spin-flipping between the Co and Nb layers.Comment: 4 pages, 4 figure
Equation of state for dense supernova matter
We provide an equation of state for high density supernova matter by applying
a momentum-dependent effective interaction. We focus on the study of the
equation of state of high-density and high-temperature nuclear matter
containing leptons (electrons and neutrinos) under the chemical equilibrium
condition. The conditions of charge neutrality and equilibrium under
-decay process lead first to the evaluation of the lepton fractions and
afterwards the evaluation of internal energy, pressure, entropy and in total to
the equation of state of hot nuclear matter for various isothermal cases.
Thermal effects on the properties and equation of state of nuclear matter are
evaluated and analyzed in the framework of the proposed effective interaction
model. Since supernova matter is characterized by a constant entropy we also
present the thermodynamic properties for isentropic case. Special attention is
dedicated to the study of the contribution of the components of -stable
nuclear matter to the entropy per particle, a quantity of great interest for
the study of structure and collapse of supernova.Comment: 23 pages, 15 figure
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