1,801 research outputs found
Pacific area data collection stations
The installation of environmental data collection systems at several remotely located sites in islands in the Pacific Ocean is summarized. The effort was designed to enhance the ability to collect hydrological information. The data collection station consists of a data acquisition system for handling data, a transmitter for uplinking information to the GOES-W geostationary satellite, and a variety of environmental sensors for data accumulation. Each system was assembled, tested, and deployed on designated islands. The concept of using microprocessors for handling data at remote sites and relaying it via a satellite link is a cost effective approach. Such systems require high reliability and proven performance in the field
A Unified Approach to Convex and Convexified Generalized Differentiation of Nonsmooth Functions and Set-Valued Mappings
In the early 1960's, Moreau and Rockafellar introduced a concept of called
\emph{subgradient} for convex functions, initiating the developments of
theoretical and applied convex analysis. The needs of going beyond convexity
motivated the pioneer works by Clarke considering generalized differentiation
theory of Lipschitz continuous functions. Although Clarke generalized
differentiation theory is applicable for nonconvex functions, convexity still
plays a crucial role in Clarke subdifferential calculus. In the mid 1970's,
Mordukhovich developed another generalized differentiation theory for nonconvex
functions and set-valued mappings in which the "umbilical cord with convexity"
no longer exists. The primary goal of this paper is to present a unified
approach and shed new light on convex and Clarke generalized differentiation
theories using the concepts and techniques from Mordukhovich's developments
Mg-Ni-H films as selective coatings: tunable reflectance by layered hydrogenation
Unlike other switchable mirrors, Mg2NiHx films show large changes in
reflection that yield very low reflectance (high absorptance) at different
hydrogen contents, far before reaching the semiconducting state. The resulting
reflectance patterns are of interference origin, due to a self-organized
layered hydrogenation mechanism that starts at the substrate interface, and can
therefore be tuned by varying the film thickness. This tunability, together
with the high absorptance contrast observed between the solar and the thermal
energies, strongly suggests the use of these films in smart coatings for solar
applications.Comment: Three two-column pages with 3 figures embedded; RevTE
Joining up health and bioinformatics: e-science meets e-health
CLEF (Co-operative Clinical e-Science Framework) is an MRC sponsored project in the e-Science programme that aims to establish methodologies and a technical infrastructure forthe next generation of integrated clinical and bioscience research. It is developing methodsfor managing and using pseudonymised repositories of the long-term patient histories whichcan be linked to genetic, genomic information or used to support patient care. CLEF concentrateson removing key barriers to managing such repositories ? ethical issues, informationcapture, integration of disparate sources into coherent ?chronicles? of events, userorientedmechanisms for querying and displaying the information, and compiling the requiredknowledge resources. This paper describes the overall information flow and technicalapproach designed to meet these aims within a Grid framework
Effect of the strong metal-support interaction on hydrogen sorption kinetics of Pd-capped switchable mirrors
The morphology and electronic structure of Pd clusters grown on oxidized yttrium surfaces are investigated by scanning tunneling microscopy and ultraviolet photoelectron spectroscopy. The hydrogen sorption mediated by the Pd clusters is determined from the optically monitored switching kinetics of the underlying yttrium film. A strong thickness dependence of the hydrogen uptake is found. The electronic structure of the as-grown Pd clusters depends only weakly on their size. Strong changes of the photoemission spectra are found after hydrogenation, in particular the oxide peak shifts and the Pd peaks vanish. Both phenomena are due to a strong metal-support interaction (SMSI) state, characterized by a complete encapsulation of the clusters by a reduced yttrium oxide layer. Scanning tunneling spectroscopy confirms the SMSI state of small Pd clusters after hydrogen exposure. The SMSI effect is less important with increasing Pd thickness. This explains the critical thickness for the catalyzed hydrogen uptake by the Pd/Y
Entry in the ADHD drugs market: Welfare impact of generics and me-toos
Recent decades have seen a growth in treatments for attention deficit hyperactivity disorder (ADHD) including many branded and generic drugs. In the early 2000's, new drug entry dramatically altered market shares. We estimate a demand system for ADHD drugs and assess the welfare impact of new drugs. We find that entry induced large welfare gains by reducing prices of substitute drugs, and by providing alternative delivery mechanisms for existing molecules. Our results suggest that the success of follow-on patented drugs may come from unanticipated innovations like delivery mechanisms, a factor ignored by proposals to retard new follow-on drug approvals
VLBI observations of seven BL Lac objects from RGB sample
We present EVN observations of seven BL Lac objects selected from the RGB
sample. To investigate the intrinsic radiation property of BL Lac objects, we
estimated the Doppler factor with the VLA or MERLIN core and the total 408 MHz
luminosity for a sample of 170 BL Lac objects. The intrinsic (comoving)
synchrotron peak frequency was then calculated by using the estimated Doppler
factor. Assuming a Lorentz factor of 5, the viewing angle of jets was
constrained. The high-resolution VLBI images of seven sources all show a
core-jet structure. We estimated the proper motions of three sources with the
VLBI archive data, and find that the apparent speed increases with the distance
of components to the core for all of them. In our BL Lacs sample, the Doppler
factor of LBLs is systematically larger than that of IBLs and HBLs. We find a
significant anti-correlation between the total 408 MHz luminosity and the
intrinsic synchrotron peak frequency. However, the scatter is much larger than
for the blazar sequence. Moreover, we find a significant positive correlation
between the viewing angle and the intrinsic synchrotron peak frequency. The BL
Lac objects show a continuous distribution on the viewing angle. While LBLs
have a smaller viewing angle than that of IBLs and HBLs, IBLs are comparable to
HBLs. We conclude that the intrinsic synchrotron peak frequency is not only
related to the intrinsic radio power (though with a large scatter), but also to
the viewing angle for the present sample.Comment: 22 pages,15figures, published by A&
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