Uromacer oxyrhynchus

Number of Pages: 2Integrative BiologyGeological Science

Uromacer catesbyi

Number of Pages: 2Integrative BiologyGeological Science

Uromacer frenatus

Number of Pages: 2Integrative BiologyGeological Science

Developing a Customized Composite Drought Index for Pakistan

Pakistan experiences frequent and intense agricultural drought, varying spatially and temporally. Prolonged dry conditions often result in failed crop production. Using multiple variables, different components of drought can be captured across a multitude of climatic zones and throughout different seasons. Developing a composite drought index (CDI), specific for each district, will provide a more complete view of agricultural drought and enhance early warning systems

AC Conductivity Relaxation Processes in CaCu₃Ti₄O₁₂ Ceramics: Grain Boundary and Domain Boundary Effects

The ac conductivity of CaCu₃Ti₄O₁₂ ceramics associated with electrical charge carrier motion (ions or vacancies) was investigated as a function of frequency at different temperatures. The long range migration of charge carriers within the ceramic is restricted by two kinds of insulating barriers, namely, grain boundaries and domain boundaries. The potential barriers associated with these boundaries lead to two anomalies in conductivity response and three frequency-dependent contributions to conductivity: long range diffusion of carriers, carrier migration localized within grains, and carrier migration localized within domains

Electroactive apparatus and methods

High performance electromechanical devices suitable for a wide range of applications are described. The electroactive devices are capable of operating in a manner that offers enhanced mechanical displacement responses and increased load-bearing capabilities. In one embodiment, the device is capable of providing a significantly increased level of free displacement. The electroactive devices include an electroactive composite which includes at least one electroactive material that may comprise an electrostrictive or a piezoelectric material and a tensioning device which is adapted for inducing a mechanical pre-load to the electroactive composite structure. The tensioning device exerts a mechanical pre-load upon the electroactive material which alters stress profile, increases mechanical energy and increases stored elastic energy of the electroactive devices

Maxwell-Wagner Relaxations and their Contributions to the High Permittivity of Calcium Copper Titanate Ceramics

Calcium copper titanate ceramics were fabricated by cold isostatic pressing at various calcination and sintering conditions. Depending on fabrication condition, three electrical responses were observed in the combined modulus and impedance plots, indicating the presence of two Maxwell-Wagner relaxations. These electrical responses show different response to temperature and applied field. The activation energies, as well as the driving force factors, were calculated for these relations. The determined activation energy values are in the range of 0.57 to 0.65 eV. The contribution of Maxwell-Wagner relaxations to the high permittivity of CCTO and related materials is briefly discussed

Combining Quote-Driven and Order-Driven Trading Systems in Next-Generation Stock Markets: An Experimental Investigation

We use computer-based simulations of a stock market as a background environment for experimental tests of the integration of an order-driven trading system into a dealer/quote-driven market. Experimental subjects traded using a traditional dealer quote screen (such as Nasdaq in the U.S. or the London Stock Exchange's SEAQ), to which was added a public limit order facility. Data captured on subjects' trading decisions under different market structures revealed that: (1) When available, the limit order facility was used by the subjects, attracting some orders that would have otherwise gone to dealers, and reducing investor trading costs. (2) The relative use of market orders and limit orders was related to the bid-ask spread; wider spreads (higher cost of immediate trading) led subjects to enter fewer market orders. (3) Limit order use was reduced when the dealers were provided with an "informational advantage. " (4) While the introduction of a limit order facility did not have a substantial effect on dealer profit margins, dealers' activities as a percentage of total market volume declined. Overall, we find the simulation environment is a workable device for analyzing the effect of market design changes on trader behavior and market quality. It can provide solid guidance on market structure issues, such as how best to incorporate a limit order facility in a competing dealer market.Information Systems Working Papers Serie