721 research outputs found
Teaching History in the Digital Age
Digital history is an approach to examining and representing the past that takes advantage of new communication technologies such as computers and the Web. It draws on essential features of the digital realm, such as databases, hypertextualization, and networks, to create and share historical knowledge. Digital history complements other forms of history—indeed, it draws its strength and methodological rigor from this age-old form of human understanding while using the latest technology. Although many humanities scholars have been talking and writing about the transition to the digital age for more than a decade, only in the last few years have we seen a convergence of the factors that make this transition possible: the spread of sufficient infrastructure on our campuses, the creation of truly massive databases of humanities content, and a generation of students that has never known a world without easy Internet access. Teaching History in the Digital Age is intended to serve as a guide for practitioners on how to fruitfully employ the transformative changes of digital media in the research, writing, teaching of history
Intermolecular interactions in N-(ferrocenylmethyl)anthracene-9-carboxamide
The title compound, [Fe(C₅H₅)(C₂₁H₁₆NO)], was synthesized from the coupling reaction of anthracene-9-carboxylic acid and ferrocenylmethylamine. The ferrocenyl (Fc) group and the anthracene ring system both lie approximately orthogonal to the amide moiety. An amide-amide interaction (along the a axis) is the principal interaction [N...O = 2.910 (2) Å]. A C-H...π(arene) interaction [C...centroid = 3.573 (2) Å] and a C-H...O interaction [C...O = 3.275 (3) Å] complete the hydrogen bonding; two short (Fc)C...C(anthracene) contacts are also present
Recommended from our members
A variable timestep generalized Runge-Kutta method for the numerical integration of the space-time diffusion equations
A generalized Runge-Kutta method has been employed in the numerical integration of the stiff space-time diffusion equations. The method is fourth-order accurate, using an embedded third-order solution to arrive at an estimate of the truncation error for automatic timestep control. The efficiency of the Runge-Kutta method is enhanced by a block-factorization technique that exploits the sparse structure of the matrix system resulting from the space and energy discretized form of the time-dependent neutron diffusion equations. Preliminary numerical evaluation using a one-dimensional finite difference code shows the sparse matrix implementation of the generalized Runge-Kutta method to be highly accurate and efficient when compared to an optimized iterative theta method. 12 refs., 5 figs., 4 tabs
Reasons, Coherence, and Group Rationality
Philosophy and Phenomenological Research, EarlyView
Why equality? On justifying liberal egalitarianism
The debate over the nature of egalitarianism has come to dominate political philosophy. As ever more sophisticated attempts are made to describe the principles of an egalitarian distribution or to specify the good or goods that should be distributed equally, little is said about the fundamental basis of equality. In virtue of what should people be regarded as equal? Egalitarians have tended to dismiss this question of fundamental equality. In the first part of the paper I will examine some of these strategies of marginalisation and assess whether the issue of fundamental equality matters. Jeremy Waldron has criticised this strategy of avoidance in his recent book God, Locke and equality. He argues that Locke's turn to a theistic grounding for fundamental equality provides a better approach to the problem than the approach taken by contemporary liberals such as John Rawls. I will examine Waldron's critique of Rawls and show that it is wanting. I will conclude by suggesting that Rawls's approach to the issue has a bearing on the way in which equality should be understood as a political value. This argument for the primacy of a political conception of egalitarianism has a bearing on the interconnection between core liberal values and the idea of the state that has been emphasised by Rawls, Dworkin and Nagel
Theory for Metal Hydrides with Switchable Optical Properties
Recently it has been discovered that lanthanum, yttrium, and other metal
hydride films show dramatic changes in the optical properties at the
metal-insulator transition. Such changes on a high energy scale suggest the
electronic structure is best described by a local model based on negatively
charged hydrogen (H) ions. We develop a many-body theory for the strong
correlation in a H ion lattice. The metal hydride is described by a large
-limit of an Anderson lattice model. We use lanthanum hydride as a prototype
of these compounds, and find LaH is an insulator with a substantial gap
consistent with experiments. It may be viewed either as a Kondo insulator or a
band insulator due to strong electron correlation. A H vacancy state in LaH
is found to be highly localized due to the strong bonding between the electron
orbitals of hydrogen and metal atoms. Unlike the impurity states in the usual
semiconductors, there is only weak internal optical transitions within the
vacancy. The metal-insulator transition takes place in a band of these vacancy
states.Comment: 18 pages, 16 figures and 6 tables. Submitted to PR
On the Study of Hyperbolic Triangles and Circles by Hyperbolic Barycentric Coordinates in Relativistic Hyperbolic Geometry
Barycentric coordinates are commonly used in Euclidean geometry. Following
the adaptation of barycentric coordinates for use in hyperbolic geometry in
recently published books on analytic hyperbolic geometry, known and novel
results concerning triangles and circles in the hyperbolic geometry of
Lobachevsky and Bolyai are discovered. Among the novel results are the
hyperbolic counterparts of important theorems in Euclidean geometry. These are:
(1) the Inscribed Gyroangle Theorem, (ii) the Gyrotangent-Gyrosecant Theorem,
(iii) the Intersecting Gyrosecants Theorem, and (iv) the Intersecting Gyrochord
Theorem. Here in gyrolanguage, the language of analytic hyperbolic geometry, we
prefix a gyro to any term that describes a concept in Euclidean geometry and in
associative algebra to mean the analogous concept in hyperbolic geometry and
nonassociative algebra. Outstanding examples are {\it gyrogroups} and {\it
gyrovector spaces}, and Einstein addition being both {\it gyrocommutative} and
{\it gyroassociative}. The prefix "gyro" stems from "gyration", which is the
mathematical abstraction of the special relativistic effect known as "Thomas
precession".Comment: 78 pages, 26 figure
- …