9,369 research outputs found
Fiber-optic push-pull sensor systems
Fiber-optic push-pull sensors are those which exploit the intrinsically differential nature of an interferometer with concommitant benefits in common-mode rejection of undesired effects. Several fiber-optic accelerometer and hydrophone designs are described. Additionally, the recent development at the Naval Postgraduate School of a passive low-cost interferometric signal demodulator permits the development of economical fiber-optic sensor systems
The Thermal Degradation of Polychloroprene
The thermal degradation of polychloroprene has been examined by thermoanalytical techniques. These indicate that under temperature programmed conditions, degradation occurs in two main stages, namely dehydrochlorination with a rate maximum (at 10/min.) of 37
A Values-Based and Integral Perspective on Strategic Management
Landrum, Gardner, and Boje apply a Model for Integral Strategy which uses internal, competitive, and external tiers of strategic planning to combine economic, social, and environmental organizational imperatives with values, social responsibility, and sustainability. Their approach seeks to balance short-term with long-term objectives and economic with non-economic concerns all while addressing the sustainability challenges facing organizations today
A Values-Based and Integral Perspective of Strategic Management
Landrum, Gardner, and Boje apply a Model for Integral Strategy which uses internal, competitive, and external tiers of strategic planning to combine economic, social, and environmental organizational imperatives with values, social responsibility, and sustainability. Their approach seeks to balance short-term with long-term objectives and economic with non-economic concerns all while addressing the sustainability challenges facing organizations today
Scintillation in the Circinus Galaxy water megamasers
We present observations of the 22 GHz water vapor megamasers in the Circinus
galaxy made with the Tidbinbilla 70m telescope. These observations confirm the
rapid variability seen earlier by Greenhill et al (1997). We show that this
rapid variability can be explained by interstellar scintillation, based on what
is now known of the interstellar scintillation seen in a significant number of
flat spectrum AGN. The observed variability cannot be fully described by a
simple model of either weak or diffractive scintillation.Comment: 10 pages, 5 figures. AJ accepte
Bringing Agriculture into the GATT: Designing Acceptable Agricultural Policies
Agricultural and Food Policy, International Relations/Trade,
Vitamin D: beyond bone.
In recent years, vitamin D has been received increased attention due to the resurgence of vitamin D deficiency and rickets in developed countries and the identification of extraskeletal effects of vitamin D, suggesting unexpected benefits of vitamin D in health and disease, beyond bone health. The possibility of extraskeletal effects of vitamin D was first noted with the discovery of the vitamin D receptor (VDR) in tissues and cells that are not involved in maintaining mineral homeostasis and bone health, including skin, placenta, pancreas, breast, prostate and colon cancer cells, and activated T cells. However, the biological significance of the expression of the VDR in different tissues is not fully understood, and the role of vitamin D in extraskeletal health has been a matter of debate. This report summarizes recent research on the roles for vitamin D in cancer, immunity and autoimmune diseases, cardiovascular and respiratory health, pregnancy, obesity, erythropoiesis, diabetes, muscle function, and aging
The Population of Damped Lyman-alpha and Lyman Limit Systems in the Cold Dark Matter Model
Lyman limit and damped Lyman-alpha absorption systems probe the distribution
of collapsed, cold gas at high redshift. Numerical simulations that incorporate
gravity and gas dynamics can predict the abundance of such absorbers in
cosmological models. We develop a semi-analytical method to correct the
numerical predictions for the contribution of unresolved low mass halos, and we
apply this method to the Katz et al. (1996) simulation of the standard cold
dark matter model (, , , ). Using
this simulation and higher resolution simulations of individual low mass
systems, we determine the relation between a halo's circular velocity and
its cross section for producing Lyman limit or damped absorption. We combine
this relation with the Press-Schechter formula for the abundance of halos to
compute the number of absorbers per unit redshift. The resolution correction
increases the predicted abundances by about a factor of two at z=2, 3, and 4,
bringing the predicted number of damped absorbers into quite good agreement
with observations. Roughly half of the systems reside in halos with circular
velocities v_c>100\kms and half in halos with 35\kms. Halos
with v_c>150\kms typically harbor two or more systems capable of producing
damped absorption. Even with the resolution correction, the predicted abundance
of Lyman limit systems is a factor of three below observational estimates,
signifying either a failure of standard CDM or a failure of these simulations
to resolve the systems responsible for most Lyman limit absorption. By
comparing simulations with and without star formation, we find that depletion
of the gas supply by star formation affects absorption line statistics at
only for column densities exceeding .Comment: AASlatex, 17 pages w/ 3 embedded ps figures. Submitted to Ap
The Neuroscience Information Framework: A Data and Knowledge Environment for Neuroscience
With support from the Institutes and Centers forming the NIH Blueprint for Neuroscience Research, we have designed and implemented a new initiative for integrating access to and use of Web-based neuroscience resources: the Neuroscience Information Framework. The Framework arises from the expressed need of the neuroscience community for neuroinformatic tools and resources to aid scientific inquiry, builds upon prior development of neuroinformatics by the Human Brain Project and others, and directly derives from the Society for Neuroscience’s Neuroscience Database Gateway. Partnered with the Society, its Neuroinformatics Committee, and volunteer consultant-collaborators, our multi-site consortium has developed: (1) a comprehensive, dynamic, inventory of Web-accessible neuroscience resources, (2) an extended and integrated terminology describing resources and contents, and (3) a framework accepting and aiding concept-based queries. Evolving instantiations of the Framework may be viewed at http://nif.nih.gov, http://neurogateway.org, and other sites as they come on line
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