29,814 research outputs found
Improved electro-optical tracking system
Electro-optical tracking system employs a laser beam illuminating source, an electronic laser beam deflector, and an image dissector photomultiplier. An electronic scanning transmitter and receiver follows rapid movements or accelerations of the target
From GM Law to A Powerful Mean Field Scheme
A new and powerful mean field scheme is presented. It maps to a
one-dimensional finite closed chain in an external field. The chain size
accounts for lattice topologies. Moreover lattice connectivity is rescaled
according to the GM law recently obtained in percolation theory. The associated
self-consistent mean-field equation of state yields critical temperatures which
are within a few percent of exact estimates. Results are obtained for a large
variety of lattices and dimensions. The Ising lower critical dimension for the
onset of phase transitions is . For the Ising hypercube it
becomes the Golden number . The scheme recovers the
exact result of no long range order for non-zero temperature Ising triangular
antiferromagnets.Comment: 3M Conference Proceedings, San Jose, California (November, 1999
Robust Hypothesis Tests for Detecting Statistical Evidence of 2D and 3D Interactions in Single-Molecule Measurements
A variety of experimental techniques have improved the 2D and 3D spatial
resolution that can be extracted from \emph{in vivo} single-molecule
measurements. This enables researchers to quantitatively infer the magnitude
and directionality of forces experienced by biomolecules in their native
cellular environments. Situations where such forces are biologically relevant
range from mitosis to directed transport of protein cargo along cytoskeletal
structures. Models commonly applied to quantify single-molecule dynamics assume
that effective forces and velocity in the (or ) directions are
statistically independent, but this assumption is physically unrealistic in
many situations. We present a hypothesis testing approach capable of
determining if there is evidence of statistical dependence between positional
coordinates in experimentally measured trajectories; if the hypothesis of
independence between spatial coordinates is rejected, then a new model
accounting for 2D (3D) interactions should be considered to more faithfully
represent the underlying experimental kinetics. The technique is robust in the
sense that 2D (3D) interactions can be detected via statistical hypothesis
testing even if there is substantial inconsistency between the physical
particle's actual noise sources and the simplified model's assumed noise
structure. For example, 2D (3D) interactions can be reliably detected even if
the researcher assumes normal diffusion, but the experimental data experiences
"anomalous diffusion" and/or is subjected to a measurement noise characterized
by a distribution differing from that assumed by the fitted model. The approach
is demonstrated on control simulations and on experimental data (IFT88 directed
transport in the primary cilium).Comment: 7 pages, 6 figure
Resolving the Uncertainty of Preterm Symptoms: Women’s Experiences With the Onset of Preterm Labor
Objective: To describe expectant women\u27s experiences with the onset of preterm labor.
Design: Qualitative, using grounded theory methods.
Setting: Southwestern tertiary women\u27s hospital.
Participants: Thirty pregnant women who were less than 35 weeks gestation, had experienced preterm labor within the past 7 days, and had no previous experience with preterm labor.
Data Source: Taped and transcribed interviews.
Results: Themes that emerged from the interview data included the following: recognition and naming of sensations, a consistent pattern of attribution of symptoms, the threat or risk inferred by the attributed cause of the symptom pattern, the associated certainty or uncertainty about these attributions, the process of interpreting and verifying symptom meaning, and the decision to self-manage the symptoms or engage health care assistance. The core process of women experiencing the onset of preterm labor symptoms was identified as resolving the uncertainty of preterm labor symptoms: recognizing and responding to the possibilities.
Conclusions: Preterm labor often is not within expectant women\u27s consciousness. They may attribute the symptoms to nonthreatening causes, which results in delays in seeking care for preterm labor. Education about symptom patterns at the onset of preterm labor will increase the probability that women and their health care providers will recognize and interpret the early, subtle symptoms that herald the onset of preterm labor. Uncertainty in illness theory and attribution theory offer frameworks for understanding women\u27s experiences with the onset of preterm labor
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Manufacturing Mechatronics Using Thermal Spray Shape Deposition
A new technology for manufacturing mechatronics is described. The technique is based on recursive
masking and deposition of thermally sprayed materials. Using these methods, mechanical structures
can be created that embed and interconnect electronic components. This results in highly integrated
mechatronic devices. A simple, electromechanical artifact was designed and produced to assess the
feasibility of these techniques. The details and limitations of this project will be discussed. Areas of
future research are identified which are aimed at realizing the full potential of this emerging manufacturing
process.Mechanical Engineerin
The extensive nature of group quality
We consider groups of interacting nodes engaged in an activity as many-body,
complex systems and analyse their cooperative behaviour from a mean-field point
of view. We show that inter-nodal interactions rather than accumulated
individual node strengths dominate the quality of group activity, and give rise
to phenomena akin to phase transitions, where the extensive relationship
between group quality and quantity reduces. The theory is tested using
empirical data on quantity and quality of scientific research groups, for which
critical masses are determined.Comment: 6 pages, 6 figures containing 13 plots. Very minor changes to
coincide with published versio
Reaction of the chick to one atmosphere of oxygen
Experiment to determine chicken reaction to 100 percent oxygen at atmospheric pressur
Embryo development and chick growth in a helium - oxygen atmosphere
Embryo development and chick growth in helium- oxygen atmospher
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