350 research outputs found
Secondary Electron Yield Measurements of Fermilab's Main Injector Vacuum Vessel
We discuss the progress made on a new installation in Fermilab's Main
Injector that will help investigate the electron cloud phenomenon by making
direct measurements of the secondary electron yield (SEY) of samples irradiated
in the accelerator. In the Project X upgrade the Main Injector will have its
beam intensity increased by a factor of three compared to current operations.
This may result in the beam being subject to instabilities from the electron
cloud. Measured SEY values can be used to further constrain simulations and aid
our extrapolation to Project X intensities. The SEY test-stand, developed in
conjunction with Cornell and SLAC, is capable of measuring the SEY from samples
using an incident electron beam when the samples are biased at different
voltages. We present the design and manufacture of the test-stand and the
results of initial laboratory tests on samples prior to installation.Comment: 3 pp. 3rd International Particle Accelerator Conference (IPAC 2012)
20-25 May 2012, New Orleans, Louisian
Cristallochemical characterization of synthetic Zn-substituted maghemites (g-Fe2-xZn xO3)
The Non-linear Dynamics of Meaning-Processing in Social Systems
Social order cannot be considered as a stable phenomenon because it contains
an order of reproduced expectations. When the expectations operate upon one
another, they generate a non-linear dynamics that processes meaning. Specific
meaning can be stabilized, for example, in social institutions, but all meaning
arises from a horizon of possible meanings. Using Luhmann's (1984) social
systems theory and Rosen's (1985) theory of anticipatory systems, I submit
equations for modeling the processing of meaning in inter-human communication.
First, a self-referential system can use a model of itself for the
anticipation. Under the condition of functional differentiation, the social
system can be expected to entertain a set of models; each model can also
contain a model of the other models. Two anticipatory mechanisms are then
possible: one transversal between the models, and a longitudinal one providing
the modeled systems with meaning from the perspective of hindsight. A system
containing two anticipatory mechanisms can become hyper-incursive. Without
making decisions, however, a hyper-incursive system would be overloaded with
uncertainty. Under this pressure, informed decisions tend to replace the
"natural preferences" of agents and an order of cultural expectations can
increasingly be shaped
Tools and data services registry: a community effort to document bioinformatics resources.
Life sciences are yielding huge data sets that underpin scientific discoveries fundamental to improvement in human health, agriculture and the environment. In support of these discoveries, a plethora of databases and tools are deployed, in technically complex and diverse implementations, across a spectrum of scientific disciplines. The corpus of documentation of these resources is fragmented across the Web, with much redundancy, and has lacked a common standard of information. The outcome is that scientists must often struggle to find, understand, compare and use the best resources for the task at hand.Here we present a community-driven curation effort, supported by ELIXIR-the European infrastructure for biological information-that aspires to a comprehensive and consistent registry of information about bioinformatics resources. The sustainable upkeep of this Tools and Data Services Registry is assured by a curation effort driven by and tailored to local needs, and shared amongst a network of engaged partners.As of November 2015, the registry includes 1785 resources, with depositions from 126 individual registrations including 52 institutional providers and 74 individuals. With community support, the registry can become a standard for dissemination of information about bioinformatics resources: we welcome everyone to join us in this common endeavour. The registry is freely available at https://bio.tools
Variabilidade de goethita e hematita via dissolução redutiva em solos de região tropical e subtropical
Sport, War and Democracy in Classical Athens
This article concerns the paradox of athletics in classical Athens. Democracy may have opened up politics to every class of Athenian but it had little impact on sporting participation. The city’s athletes continued to drawn predominantly from the upper class. It comes as a surprise then that lower-class Athenians actually esteemed athletes above every other group in the public eye, honoured them very generously when they won, and directed a great deal of public and private money to sporting competitions and facilities. In addition athletics escaped the otherwise persistent criticism of upper-class activities in the popular culture of the democracy. The research of social scientists on sport and aggression suggests this paradox may have been due to the cultural overlap between athletics and war under the Athenian democracy. The article concludes that the practical and ideological democratization of war by classical Athens legitimized and supported upper-class sport
Mineralogia e susceptibilidade magnética dos óxidos de ferro do horizonte B de solos do Estado do Paraná
Influência de fatores ambientais na distribuição de famílias de insetos aquáticos em rios no sul do Brasil
Reversible coagulation of colloidal suspension in shallow potential wells: Direct numerical simulation
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