The increased deterioration of existing groundwater resources and gradual decline in costs of freshwater water production, have given new impetus to the use of desalination plants in arid lands. Nonetheless, the formation of scale on heat transfer surfaces could profoundly reduce the efficiency of thermal desalination plants. The widely used practice to mitigate scale formation in such units is...

We demonstrate a new design of Ge-based electrodes comprising three-dimensional (3-D) spherical microflowers containing crystalline nanorod networks on sturdy 1-D nanostems directly grown on a metallic current collector by facile thermal evaporation. The Ge nanorod networks were observed to self-replicate their tetrahedron structures and form a diamond cubic lattice-like inner network. After et...

William Walker is professor of international relations at the University of St. Andrews in Scotland. He is the co-author with David Albright and Frans Berkhout of SIPRI’s Plutonium and Highly Enriched Uranium: World Inventories, Capabilities and Policies (forthcoming, 1996). There have been many recent cases of states reversing course. Russia has embraced capitalism and democracy, China has thr...

What is the impact of surprise and anticipated policy changes when agents form expectations using adaptive learning rather than rational expectations? We examine this issue using the standard stochastic real business cycle model with lump-sum taxes. Agents combine knowledge about future policy with econometric forecasts of future wages and interest rates. Dynamics under learning can have large ...

We have ∀X.A′ ≺ ∀X.B, so A′ ≺ B. Also, we have Σ ` V X : A′, so the RHS has type B = A. • Case (V : A′ p =⇒ ∀X.B) X 7−→ V : A′ p =⇒ B : We have A′ ≺ ∀X.B, so A′ ≺ B. Thus, the RHS has type B = A. • Case V : ∀X.A′ p =⇒ B 7−→ (V ?) : A′[X:=?] p =⇒ B : We have ∀X.A′ ≺ B, so A′[X:=?] ≺ B by Lemma 1. Thus, the RHS has type B. Definition 3. Well-typed contexts, written Σ B E : B ⇒ A, are defined in t...

Siek and Taha [2006] coined the term gradual typing to describe a theory for integrating static and dynamic typing within a single language that 1) puts the programmer in control of which regions of code are statically or dynamically typed and 2) enables the gradual evolution of code between the two typing disciplines. Since 2006, the term gradual typing has become quite popular but its meaning...

In recent years, many systems have been developed which aim at helping users to find pieces of information or other objects that are in accordance with their personal interests. In these systems, machine learning methods are often used to acquire the user interest profile. Frequently user interests drift with time. The ability to adapt fast to the current user's interests is an important featur...