3,191 research outputs found
Ideabook: Libraries for Families
The IDEABOOK is a research-based framework to guide and broaden family engagement in libraries.The framework helps libraries move beyond thinking of family engagement as random, individual activities or programs, but rather as a system where library leadership, activities, and resources that are linked to goals. The framework represents a theory of change that begins with a set of elements—leadership, engagement, and support services—that build a pathway for meaningful family engagement beginning in the early childhood years and extending through young adulthood.This IDEABOOK was developed for anyone who works in a library setting—from library directors and children's and youth librarians, to volunteers and support staff—and shares many innovative ways that libraries support and guide families in children's learning and development
Influence of bottom topography on integral constraints in zonal flows with parameterized potential vorticity fluxes
An integral constraint for eddy fluxes of potential vorticity (PV), corresponding to global momentum conservation, is applied to two-layer zonal quasi-geostrophic channel flow. This constraint must be satisfied for any type of parameterization of eddy PV fluxes. Bottom topography strongly influence the integral constraint compared to a flat bottom channel. An analytical solution for the mean flow solution has been found by using asymptotic expansion in a small parameter which is the ratio of the Rossby radius to the meridional extent of the channel. Applying the integral constraint to this solution, one can find restrictions for eddy PV transfer coefficients which relate the eddy fluxes of PV to the mean flow. These restrictions strongly deviate from restrictions for the channel with flat bottom topography
GiRaFFE: An Open-Source General Relativistic Force-Free Electrodynamics Code
We present GiRaFFE, the first open-source general relativistic force-free
electrodynamics (GRFFE) code for dynamical, numerical-relativity generated
spacetimes. GiRaFFE adopts the strategy pioneered by McKinney and modified by
Paschalidis and Shapiro to convert a GR magnetohydrodynamic (GRMHD) code into a
GRFFE code. In short, GiRaFFE exists as a modification of IllinoisGRMHD, a
user-friendly, open-source, dynamical-spacetime GRMHD code. Both GiRaFFE and
IllinoisGRMHD leverage the Einstein Toolkit's highly-scalable infrastructure to
make possible large-scale simulations of magnetized plasmas in strong,
dynamical spacetimes on adaptive-mesh refinement (AMR) grids. We demonstrate
that GiRaFFE passes a large suite of both flat and curved-spacetime code tests
passed by a number of other state-of-the-art GRFFE codes, and is thus ready for
production-scale simulations of GRFFE phenomena of key interest to relativistic
astrophysics.Comment: 23 pages, 4 figures. Consistent with published versio
A systematic correlation between two-dimensional flow topology and the abstract statistics of turbulence
Velocity differences in the direct enstrophy cascade of two-dimensional
turbulence are correlated with the underlying flow topology. The statistics of
the transverse and longitudinal velocity differences are found to be governed
by different structures. The wings of the transverse distribution are dominated
by strong vortex centers, whereas, the tails of the longitudinal differences
are dominated by saddles. Viewed in the framework of earlier theoretical work
this result suggests that the transfer of enstrophy to smaller scales is
accomplished in regions of the flow dominated by saddles.Comment: 4 pages, 4 figure
Random Projections For Large-Scale Regression
Fitting linear regression models can be computationally very expensive in
large-scale data analysis tasks if the sample size and the number of variables
are very large. Random projections are extensively used as a dimension
reduction tool in machine learning and statistics. We discuss the applications
of random projections in linear regression problems, developed to decrease
computational costs, and give an overview of the theoretical guarantees of the
generalization error. It can be shown that the combination of random
projections with least squares regression leads to similar recovery as ridge
regression and principal component regression. We also discuss possible
improvements when averaging over multiple random projections, an approach that
lends itself easily to parallel implementation.Comment: 13 pages, 3 Figure
Evolving American Investing Attitudes: The Hybrid Shift In Mutual Fund Distribution
This paper studies the dramatic evolution in the way American investors choose to invest in the mutual fund industry. The industry’s change from direct-to-shareholder model to a third-party distribution model is discussed, as well as the implications for future mutual fund investors. Ever since the first recorded asset and debt managers arose in the 14th and 15th centuries in Europe, investing has grown into a tug-and-pull type of system that the human mind seems drawn to. The way that Americans choose to invest their money is changing as we enter the 21st century and the new methods and procedures are having a greater impact than many of us realize. In the U.S., trillions of dollars each year are invested in mutual funds, but more and more investors are taking a less-involved route by allowing financial analysts to choose where their money is invested. In the following pages, we will take a closer look at the mutual fund market and its basic components, the ways that mutual funds have been viewed and traded in the past, and the revolutionary changes that are happening right under our noses that the average American may not even be aware of. With the help of many credible sources, such as the Investment Company Institute, Reflow Investments LLC, and the Financial Planning Journal, the change from direct-to-shareholder mutual fund distribution to third-party intermediary distribution will be explained and the effects these changes has on the average investor will be explored
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