8,035 research outputs found
Energetics, skeletal dynamics and long-term predictions in Kolmogorov-Lorenz systems
We study a particular return map for a class of low dimensional chaotic
models called Kolmogorov Lorenz systems, which received an elegant general
Hamiltonian description and includes also the famous Lorenz63 case, from the
viewpoint of energy and Casimir balance. In particular it is considered in
detail a subclass of these models, precisely those obtained from the Lorenz63
by a small perturbation on the standard parameters, which includes for example
the forced Lorenz case in Ref.[6]. The paper is divided into two parts. In the
first part the extremes of the mentioned state functions are considered, which
define an invariant manifold, used to construct an appropriate Poincare surface
for our return map. From the experimental observation of the simple orbital
motion around the two unstable fixed points, together with the circumstance
that these orbits are classified by their energy or Casimir maximum, we
construct a conceptually simple skeletal dynamics valid within our sub class,
reproducing quite well the Lorenz map for Casimir. This energetic approach
sheds some light on the physical mechanism underlying regime transitions. The
second part of the paper is devoted to the investigation of a new type of
maximum energy based long term predictions, by which the knowledge of a
particular maximum energy shell amounts to the knowledge of the future
(qualitative) behaviour of the system. It is shown that, in this respect, a
local analysis of predictability is not appropriate for a complete
characterization of this behaviour. A perspective on the possible extensions of
this type of predictability analysis to more realistic cases in (geo)fluid
dynamics is discussed at the end of the paper.Comment: 21 pages, 14 figure
Mobilizing Public Will For Social Change
Examines the theory and strategies of "public will" campaigns and offers tangible criteria for their evaluation. It provides a rich inventory of strategies for use in mobilizing the public will through an integration of models of agenda building, social problem construction, issues management, social movements, media advocacy, and social capital. In addition, the paper provides cases and examples of public will campaigns directed at various social problems, along with criteria for evaluating these campaigns at various stages of a social problem's life cycle
Open educational practices for curriculum enhancement
Open educational resources (OER) and open educational practices (OEP) are relatively new areas in educational research. How OER and OEP can help practitioners enhance curricula is one of a number of under-researched topics. This article aims to enable practitioners to identify and implement appropriate open practices to enhance higher education curricula. To that aim, we put forward a framework of four open educational practices based on patterns of OER reuse (‘as is’ or adapted), mapped against the processes of curriculum design and delivery. The framework was developed from the in-depth analysis of 20 cases of higher education practitioners, which revealed patterns of OER reuse across disciplines, institutions and needs. For each open practice we offer evidence, examples and ideas for application by practitioners. We also put forward recommendations for institutional policies on OER and OE
Vortex line representation for flows of ideal and viscous fluids
It is shown that the Euler hydrodynamics for vortical flows of an ideal fluid
coincides with the equations of motion of a charged {\it compressible} fluid
moving due to a self-consistent electromagnetic field. Transition to the
Lagrangian description in a new hydrodynamics is equivalent for the original
Euler equations to the mixed Lagrangian-Eulerian description - the vortex line
representation (VLR). Due to compressibility of a "new" fluid the collapse of
vortex lines can happen as the result of breaking (or overturning) of vortex
lines. It is found that the Navier-Stokes equation in the vortex line
representation can be reduced to the equation of the diffusive type for the
Cauchy invariant with the diffusion tensor given by the metric of the VLR
Kedudukan dan Kewenangan Dewan Perwakilan Daerah dalam Sistem Ketatanegaraan Indonesia
Functioned as a regional representative council, DPD possessing a regional representative character principally has a broader representative character compared to DPR (Legislative Assembly). It is because its representative dimensions are based on all of the citizens living in the regions. The issues being studied include (1) Is the existence of DPD in line with the idea of its establishment based on the bicameral legislative system?, (2) Is the constitutional authority of DPD synchronic with its existence as a state institution? This is a normative research focused on primary and secondary materials of law including the regulation of law and the literatures relevant as the research object. In obtaining the primary and secondary materials, a library research was conducted by involving a descriptive-qualitativeanalysis. The research result then shows the existence of DPD in relationship with DPR and MPR as regulated in the Constitution of 1945 is not in line with the thought of its establishment. At this point, the reform on the structure of Indonesia Constitution toward a strong bicameralism is not materialized in the Constitution of 1945
The interpretation of spikes and trends in concentration of nitrate in polar ice cores, based on evidence from snow and atmospheric measurements
Nitrate is frequently measured in ice cores, but its interpretation remains immature. Using daily snow surface concentrations of nitrate at Halley (Antarctica) for 2004 - 2005, we show that sharp spikes (> factor 2) in nitrate concentration can occur from day to day. Some of these spikes will be preserved in ice cores. Many of them are associated with sharp increases in the concentration of sea salt in the snow. There is also a close association between the concentrations of aerosol nitrate and sea salt aerosol. This evidence is consistent with many of the spikes in deposited nitrate being due to the conversion or trapping of gas- phase nitrate, i. e. to enhanced deposition rather than enhanced atmospheric concentrations of NOy. Previously, sharp spikes in nitrate concentration (with concentration increases of up to a factor 4 seen in probably just one snowfall) have been assigned to sharp production events such as solar proton events (SPEs). We find that it is unlikely that SPEs can produce spikes of the kind seen. Taken together with our evidence that such spikes can be produced depositionally, we find that it is not possible to track past SPEs without carrying out a new multi- site and multi- analyte programme. Seasonal and interannual trends in nitrate concentration in cores from any single site cannot be interpreted in terms of production changes until the recycling of nitrate from central Antarctica to coastal Antarctica is better quantified. It might be possible to assess the interannual input of NOy to the Antarctic lower troposphere by using a network of cores to estimate variability in the total annual deposition across the continent (which we estimate to be 9 +/- 2 x 10(7) kg/a - as NO3-), but it will first have to be established that the outflow across the coast can be ignored
Slow flows of an relativistic perfect fluid in a static gravitational field
Relativistic hydrodynamics of an isentropic fluid in a gravitational field is
considered as the particular example from the family of Lagrangian
hydrodynamic-type systems which possess an infinite set of integrals of motion
due to the symmetry of Lagrangian with respect to relabeling of fluid particle
labels. Flows with fixed topology of the vorticity are investigated in
quasi-static regime, when deviations of the space-time metric and the density
of fluid from the corresponding equilibrium configuration are negligibly small.
On the base of the variational principle for frozen-in vortex lines dynamics,
the equation of motion for a thin relativistic vortex filament is derived in
the local induction approximation.Comment: 4 pages, revtex, no figur
The Application of Network Analysis to the Study of Trial Courts
In the late 1960s, scholars began studying trial courts as organizations. Since the last large wave of these studies in the 1990s, there have been reforms that purport to alter state court institutions. The literature on trial courts has not yet addressed how reforms, like specialized courts, alter trial courts as organizations. Studies of trial courts could also profit from the application of other methods for analyzing organizations. This article explores the use of network analysis to examine the organizational linkages and structure of trial courts. After reviewing the literature on trial courts and recent court reforms, we make a case for the utility of this methodological approach. Recent computer applications of network analysis can visually map the linkages between trial court actors and the organizations that work with them. As a demonstration, we provide some of the results of our study of a state trial court located in a medium-size U.S. city. We conclude by arguing that network analysis as a technique can help scholars test past assumptions about the organization of courts and explore new linkages that are proposed by the adoption of court reforms
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