Using the principle of causality as expressed in the Kramers-Kronig relations, we derive a generalized criterion for a negative refractive index that admits imperfect transparency at an observation frequency omega. It also allows us to relate the global properties of the loss (i.e., its frequency response) to its local behavior at omega. However, causality-based criteria rely on the group veloc...

for every hyperbolic structure X on S (see [15] and [25]). The proof involves writing down words in the fundamental group which are not conjugate, but because of certain trace relations, they have the same trace squared with respect to every representation into PSL2(R) (see Section 3). The hyperbolic metrics are of course very special, and it seems reasonable that if γ and γ are as above, there...

This paper proposes a new type of growth rate, called the “poverty equivalent growth rate” (PEGR), which takes into account both the growth rate in mean income and how the benefits of growth are distributed between the poor and the non-poor. The proposed measure satisfies a basic requirement that the proportional reduction in poverty is a monotonically increasing function of the PEGR. Thus, max...

Evidence suggests that binding, or encoding a feature with respect to other features in time and space, can convey cognitive advantages. However, evidence across many kinds of stimuli and paradigms presents a mixed picture, alternatively showing cognitive costs or cognitive advantages associated with maintaining bound representations. We examined memory for colored letters drawn from similar an...

Let (X, d) be a metric space and m ∈ X. Suppose that φ : X×X → R is a nonnegative symmetric function. We define a metric d on X which is equivalent to d. If d is totally bounded, its completion is a compactification of (X, d). As examples, we construct two compactifications of (R, dE), where dE is the Euclidean metric and s ≥ 2. key words. equivalent metric; completion; compactification Mathema...

specialist microfinance institutions (MFIs). The Central Bank of Sri Lanka (CBSL) has traditionally pursued an active "developmental" role in the microfinance sector, although this has been changing. It should further reduce its developmental activities by diluting its ownership of regional development banks and taking a less hands-on role in project implementation. Conversely, it would be appr...

Alan Turing’s fundamental inquiry asking “Can Machines think?” has given rise to a wide variety of contrasting approaches to building intelligent machines. Thinking requires that a computer must know what it processes and form conscious about meaningful concepts based on which subjective mental activities (e.g. seeing, knowing, learning, judging, evaluating, deciding, reasoning, etc.) can be ca...