8,511 research outputs found
Internet Taxes: Congressional Efforts to Control States\u27 Ability to Tax the World Wide Web
Every year, increasingly more people use the Internet to purchase goods and services. Internet purchases are expected to exceed 1.3 trillion. Presently, the majority of Internet sales transactions flow through business to business sites. Internet purchases by consumers are expected to reach $144 billion by the year 2003
Quantum Critical Behavior in Kondo Systems
This article briefly reviews three topics related to the quantum critical
behavior of certain heavy-fermion systems. First, we summarize an extended
dynamical mean-field theory for the Kondo lattice, which treats on an equal
footing the quantum fluctuations associated with the Kondo and RKKY couplings.
The dynamical mean-field equations describe an effective Kondo impurity model
with an additional coupling to vector bosons. Two types of quantum phase
transition appear to be possible within this approach---the first a
conventional spin-density-wave transition, the second driven by local physics.
For the second type of transition to be realized, the effective impurity model
must have a quantum critical point exhibiting an anomalous local spin
susceptibility. In the second part of the paper, such a critical point is shown
to occur in two variants of the Kondo impurity problem. Finally, we propose an
operational test for the existence of quantum critical behavior driven by local
physics. Neutron scattering results suggest that CeCuAu passes this
test.Comment: 6 pages, 4 eps figures, REVTeX (epsf style
Analysis of dependence among size, rate and duration in internet flows
In this paper we examine rigorously the evidence for dependence among data
size, transfer rate and duration in Internet flows. We emphasize two
statistical approaches for studying dependence, including Pearson's correlation
coefficient and the extremal dependence analysis method. We apply these methods
to large data sets of packet traces from three networks. Our major results show
that Pearson's correlation coefficients between size and duration are much
smaller than one might expect. We also find that correlation coefficients
between size and rate are generally small and can be strongly affected by
applying thresholds to size or duration. Based on Transmission Control Protocol
connection startup mechanisms, we argue that thresholds on size should be more
useful than thresholds on duration in the analysis of correlations. Using
extremal dependence analysis, we draw a similar conclusion, finding remarkable
independence for extremal values of size and rate.Comment: Published in at http://dx.doi.org/10.1214/09-AOAS268 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Live Case Analysis: Pedagogical Problems And Prospects In Management Education
The selection of an appropriate and effective pedagogy has been a central theme in management education for decades. There currently exists a wide range of pedagogical options designed to match course content with the most appropriate technique(s) for effective learning outcomes. Most recently, a variety of experiential learning methods have been employed to provide students with real-life experiences and applications in the overall class design. Live case analysis is typically identified as one of a series of options within the domain of experiential learning methods. This paper examines the live case approach as a tool for achieving desired outcomes in management education. Perspectives are offered from multiple stakeholder groups that highlight both the challenges and prospects in the use of this method of teaching. Results demonstrate the usefulness of the live case approach for achieving assessment objectives and measuring important program outcomes
Conservation status of New Zealand freshwater invertebrates, 2013
The conservation status of 644 freshwater invertebrate taxa, across five Phyla, 28 Orders and 75 Families, was assessed using the New Zealand Threat Classification System (NZTCS) criteria. Forty-six species were ranked Nationally Critical, 11 Nationally Endangered and 16 Nationally Vulnerable. One hundred and seventy-two taxa were listed as Data Deficient. A full list is presented, along with summaries and brief notes on the most important changes. This list replaces all previous NZTCS lists for freshwater invertebrates
Quantized Friction across Ionic Liquid Thin Films
Ionic liquids, salts in the liquid state under ambient conditions, are of
great interest as precision lubricants. Ionic liquids form layered structures
at surfaces, yet it is not clear how this nano-structure relates to their
lubrication properties. We measured the friction force between atomically
smooth solid surfaces across ionic liquid films of controlled thickness in
terms of the number of ion layers. Multiple friction-load regimes emerge, each
corresponding to a different number of ion layers in the film. In contrast to
molecular liquids, the friction coefficients differ for each layer due to their
varying composition
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