5,019 research outputs found
Disordered hyperuniformity in two-component non-additive hard disk plasmas
We study the behavior of a two-component plasma made up of non-additive hard
disks with a logarithmic Coulomb interaction. Due to the Coulomb repulsion,
long-wavelength total density fluctuations are suppressed and the system is
globally hyperuniform. Short-range volume effects lead to phase separation or
to hetero-coordination for positive or negative non-additivities, respectively.
These effects compete with the hidden long-range order imposed by
hyperuniformity. As a result, the critical behavior of the mixture is modified,
with long-wavelength concentration fluctuations partially damped when the
system is charged. It is also shown that the decrease of configurational
entropy due to hyperuniformity originates from contributions beyond the
two-particle level. Finally, despite global hyperuniformity, we show that in
our system, the spatial configuration associated with each component separately
is not hyperuniform, i.e., the system is not "multihyperuniform.
Cryogenic scanning force microscopy of quantum Hall samples: Adiabatic transport originating in anisotropic depletion at contact interfaces
Anisotropic magneto resistances and intrinsic adiabatic transport features
are generated on quantum Hall samples based on an (Al,Ga)As/GaAs
heterostructure with alloyed Au/Ge/Ni contacts. We succeed to probe the
microscopic origin of these transport features with a cryogenic scanning force
microscope (SFM) by measuring the local potential distribution within the
two-dimensional electron system (2DES). These local measurements reveal the
presence of an incompressible strip in front of contacts with insulating
properties depending on the orientation of the contact/2DES interface line
relatively to the crystal axes of the heterostructure. Such an observation
gives another microscopic meaning to the term 'non-ideal contact' used in
context with the Landauer-B\"uttiker formalism applied to the quantum Hall
effect.Comment: 5 pages, 4 figure
A sound card based multi-channel frequency measurement system
For physical processes which express themselves as a frequency, for example
magnetic field measurements using optically-pumped alkali-vapor magnetometers,
the precise extraction of the frequency from the noisy signal is a classical
problem. We describe herein a frequency measurement system based on an
inexpensive commercially available computer sound card coupled with a software
single-tone estimator which reaches Cram\'er--Rao limited performance, a
feature which commercial frequency counters often lack. Characterization of the
system and examples of its successful application to magnetometry are
presented.Comment: 4 pages, 3 figures, 1 tabl
Estate Planning for the Senior Adult
This thesis will focus on the study of developing a marketing strategy for an attorney firm with the main focus being estate planning and wills. Statistics show that approximately 77 million Americans born between 1946 and 1964 are now entering middle age. This represents one-third of the population in the United States who will be the senior citizens of the next century. Due to increasing life spans, the eider\u27s role and societal views, this age group demands a change of their needs. These needs not only include elements suclh as Social Security and housing but a broader perspective of planning for the future, both physically and financially. They also require the tools to begin planning for the future before it is too late.
The purpose of this study is to research various estate planning tools. The end product will be the ability to plan for the future now with the utilization of legal referrals and advice.
Once the survey and marketing materials were prepared, an attorney was asked to review the results and provide input on the research in order to provide a beneficial marketing strategy for the firm. The results of the research rendered a marketing strategy and marketing tools for Kramer & Frank, P.C., a law firm located in St. Louis, Missouri
The Use of Autologous Platelet Lysate in the Expansion of Equine Bone Marrow Derived Mesenchymal Stem Cells
Fetal bovine serum (FBS) has a been standard supplement for mesenchymal stem cell (MSC) culture mediums. Unfortunately the use of this supplement can cause xenogenic reactions when contaminated MSCs are injected into the patient. Researchers have begun searching for alternative autologous and allogenic growth supplements and found hope in platelet lysate. Platelets and their abundant growth factors might allow for cell proliferation. Use of platelet lysate (PL) will eliminate the problem of xenogenic reaction. The use of autologous platelet lysate as a viable medium supplement for equine bone marrow derived MSCs was assessed through this research. This was accomplished by comparing the MSC proliferation in 10% serum supplemented media. FBS and PL were used as the serum sources and a 10% FBS containing heparin medium was also tested as a control for heparin in the platelet lysate supplement. MSC proliferation was assessed using cell counts and colony forming unit assays. Preliminary data showed greater MSC proliferation in the PL and FBS heparin supplemented mediums compared to FBS alone. Flow cytometry was performed to assay for the presence of cell surface markers. The 10% PL group were positive for cell surface markers CD-90 and negative for CD-45 and MHC-II, while the 10% FBS and 10% FBS groups were negative for CD-45 but showed variable results with regards to CD-90 and MHC-II. Each group will be further assessed on its ability to undergo trilineage differentiation. Unaltered MSCs should possess the ability to differentiate into osteocytes, chondrocytes, and adipocytes. ELISA tests will also be performed to determine the concentration of platelet-derived growth factor (PDGF) in platelet lysate samples
Effective interactions and phase behaviour for a model clay suspension in an electrolyte
Since the early observation of nematic phases of disc-like clay colloids by
Langmuir in 1938, the phase behaviour of such systems has resisted theoretical
understanding. The main reason is that there is no satisfactory generalization
for charged discs of the isotropic DLVO potential describing the effective
interactions between a pair of spherical colloids in an electrolyte. In this
contribution, we show how to construct such a pair potential, incorporating
approximately both the non-linear effects of counter-ion condensation (charge
renormalization) and the anisotropy of the charged platelets. The consequences
on the phase behaviour of Laponite dispersions (thin discs of 30 nm diameter
and 1 nm thickness) are discussed, and investigation into the mesostructure via
Monte Carlo simulations are presented.Comment: LaTeX, 12 pages, 11 figure
On phase behavior and dynamical signatures of charged colloidal platelets
We investigate the competition between anisotropic excluded-volume and
repulsive electrostatic interactions in suspensions of thin charged colloidal
discs, by means of Monte-Carlo simulations and dynamical characterization of
the structures found. We show that the original intrinsic anisotropy of the
electrostatic potential between charged platelets, obtained within the
non-linear Poisson-Boltzmann formalism, not only rationalizes the generic
features of the complex phase diagram of charged colloidal platelets such as
Gibbsite and Beidellite clays, but also predicts the existence of novel
structures. In addition, we find evidences of a strong slowing down of the
dynamics upon increasing density.Comment: 6 pages, 6 Figure
Pomelo, a tool for computing Generic Set Voronoi Diagrams of Aspherical Particles of Arbitrary Shape
We describe the development of a new software tool, called "Pomelo", for the
calculation of Set Voronoi diagrams. Voronoi diagrams are a spatial partition
of the space around the particles into separate Voronoi cells, e.g. applicable
to granular materials. A generalization of the conventional Voronoi diagram for
points or monodisperse spheres is the Set Voronoi diagram, also known as
navigational map or tessellation by zone of influence. In this construction, a
Set Voronoi cell contains the volume that is closer to the surface of one
particle than to the surface of any other particle. This is required for
aspherical or polydisperse systems.
Pomelo is designed to be easy to use and as generic as possible. It directly
supports common particle shapes and offers a generic mode, which allows to deal
with any type of particles that can be described mathematically. Pomelo can
create output in different standard formats, which allows direct visualization
and further processing. Finally, we describe three applications of the Set
Voronoi code in granular and soft matter physics, namely the problem of
packings of ellipsoidal particles with varying degrees of particle-particle
friction, mechanical stable packings of tetrahedra and a model for liquid
crystal systems of particles with shapes reminiscent of pearsComment: 4 pages, 9 figures, Submitted to Powders and Grains 201
Theory of double resonance magnetometers based on atomic alignment
We present a theoretical study of the spectra produced by
optical-radio-frequency double resonance devices, in which resonant linearly
polarized light is used in the optical pumping and detection processes. We
extend previous work by presenting algebraic results which are valid for atomic
states with arbitrary angular momenta, arbitrary rf intensities, and arbitrary
geometries. The only restriction made is the assumption of low light intensity.
The results are discussed in view of their use in optical magnetometers
- …