9,868 research outputs found
A virtual laboratory system for physiology teaching
The problem of understanding physiological processes can be aided by visualization tools. Traditionally this has been achieved by the use of schematic paper diagrams. However, many physiological processes are quite complex, and in many instances students encounter difficulties in understanding the dynamics. This paper describes the rationale behind an alternative approach using interactive three‐dimensional computer‐graphics simulation to aid comprehension of scientific concepts
High Contrast Imaging and Wavefront Control with a PIAA Coronagraph: Laboratory System Validation
The Phase-Induced Amplitude Apodization (PIAA) coronagraph is a high
performance coronagraph concept able to work at small angular separation with
little loss in throughput. We present results obtained with a laboratory PIAA
system including active wavefront control. The system has a 94.3% throughput
(excluding coating losses) and operates in air with monochromatic light.
Our testbed achieved a 2.27e-7 raw contrast between 1.65 lambda/D (inner
working angle of the coronagraph configuration tested) and 4.4 lambda/D (outer
working angle). Through careful calibration, we were able to separate this
residual light into a dynamic coherent component (turbulence, vibrations) at
4.5e-8 contrast and a static incoherent component (ghosts and/or polarization
missmatch) at 1.6e-7 contrast. Pointing errors are controlled at the 1e-3
lambda/D level using a dedicated low order wavefront sensor.
While not sufficient for direct imaging of Earth-like planets from space, the
2.27e-7 raw contrast achieved already exceeds requirements for a ground-based
Extreme Adaptive Optics system aimed at direct detection of more massive
exoplanets. We show that over a 4hr long period, averaged wavefront errors have
been controlled to the 3.5e-9 contrast level. This result is particularly
encouraging for ground based Extreme-AO systems relying on long term stability
and absence of static wavefront errors to recover planets much fainter than the
fast boiling speckle halo.Comment: 18 pages, 12 figures. Accepted for publication in PASP. The pointing
control scheme for this system is described in a separate paper
(Coronagraphic Low-Order Wave-Front Sensor: Principle and Application to a
Phase-Induced Amplitude Coronagraph, The Astrophysical Journal, Volume 693,
Issue 1, pp. 75-84 (2009)
National Laboratory System
The National Laboratory System was established to ensure a strong system of integrated public health, hospital, and independent laboratories. The goal is to strengthen critical testing and communication for public health issues through systematic improvements in the delivery of laboratory ser vices. Facilitated collaboration among state public health laboratories and their clinical laboratory constituents fulfills the directive in recent government appropriations to integrate the work of clinical and public health laboratories to assure preparedness for bioterrorism through planning, training, coordination, communication, and standardization of methods.The NLS is pro-active, allowing each state to prioritize its efforts towards bioter rorism and various public health threats such as foodborne diseases, antimicrobial resistance, and chronic health threats. It has flexibility of scope so that resources can be diverted to any public health crisis. Model projects have demonstrated that recent funding is best utilized to connect private and public health laboratories with a designated laboratory program advisor in each of the fifty states. Other components include a system for routine and emergency communication, advisory committees, ongoing laboratory training programs, and the National Laborator y Database, a comprehensive, state-centered inventory of laboratories, testing services and practices. The National Laborator y System is supported by the Division of Laboratory Systems within the Public Health Practice Program Office of the CDC.Publication date from document properties.NLS%20BROCHURE.pd
Voyager capsule phase B. Volume III - Surface laboratory system. Part D - Operational support equipment Final report
Voyager capsule surface laboratory system - operational support equipmen
The phase free, longitudinal, magnetic component of vacuum electromagnetism
A charge moving in a reference laboratory system with constant velocity
{\bf V} in the -axis produces in the -axis a longitudinal, phase free,
vacuum magnetic field which is identified as the radiated field
of Evans, Vigier and others.Comment: ReVTeX file, 7pp., no figure
Coulomb effects in the spin-dependent contribution to the intra-beam scattering rate
Coulomb effects in the intra-beam scattering are taken into account in a way
providing correct description of the spin-dependent contribution to the beam
loss rate. It allows one to calculate this rate for polarized beams
at arbitrarily small values of the ratio ,
characterizing relative change of the electron energy in the laboratory system
during scattering event.Comment: 8 pages, 2 figure
Isotopic Production Cross Sections in Proton-Nucleus Collisions at 200 MeV
Intermediate mass fragments (IMF) from the interaction of Al,
Co and Au with 200 MeV protons were measured in an angular range
from 20 degree to 120 degree in the laboratory system. The fragments, ranging
from isotopes of helium up to isotopes of carbon, were isotopically resolved.
Double differential cross sections, energy differential cross sections and
total cross sections were extracted.Comment: accepted by Phys. Rev.
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