Predatory Insects and Spiders From Suburban Lawns in Lexington, Kentucky

Predatory arthropods were caught in pitfall traps in suburban lawns in Lexington, Kentucky. The relative abundance of species of Lycosidae, Carabidae, and Staphylinidae was compared in Kentucky bluegrass and tall fescue turf. Nine species of Lycosidae were collected from both the bluegrass and tall fescue lawns. More species or phena of Carabidae were collected from bluegrass than from tall fescue turf. More than 40 species or phena of staphylinids were collected from each grass habitat. Both Kentucky bluegrass and tall fescue are inhabited by an abundant and diverse array of predatory arthropods

The macroeconomics of delayed exchange-rate unification : theory and evidence from Tanzania

Parallel exchange-rate markets have often been dismissed by authorities as a nuisance or as the domain of a small group of economic saboteurs. Using Tanzania as a case study, the authors argue instead that these markets played a central macroeconomicrole in the 1970s and 1980s. They provide a rigorous macroeconomic analysis of the parallel foreign-exchange market and its fiscal implications. First, they investigate the evolution of that market in Tanzania from the mid-1960s to 1990. That period stretched from the adoption of exchange controls to macroeconomic collapse and then to subsequent reforms in the mid- to late 1980s. A reduced -form econometric equation (of a Dornbusch stock-flow model type) indicates that both trade and financial portfolio factors were important in determining the parallel premium, with trade determinants the parallel premium, with trade determinants dominating in the long run, as theory suggests. Then they investigate the fiscal impact of the parallel exchange-rate premium, an issue emphasized in the literature on exchange-rate unification. They construct a counterfactual simulation of fiscal and balance-of-payments flows under alternative assumptions about the indexing of those flows to the parallel and official exchange rate. They find that a more aggressive move toward exchange-rate unification would have already delivered a fiscal bonus by the mid-1980s. Accordingly, unification of the exchange rate would have reduced monetary growth and inflationary pressures. So, contrary to conventional advice often given in Africa and elsewhere, the case of Tanzania suggests that from a fiscal viewpoint there was no economic rationale for gradualism in exchange-rate unification and delay of a move toward convertibility.Economic Theory&Research,Banks&Banking Reform,Fiscal&Monetary Policy,Payment Systems&Infrastructure,Environmental Economics&Policies,Economic Theory&Research,Macroeconomic Management,Fiscal&Monetary Policy,Environmental Economics&Policies,Economic Stabilization

Taxes, Fringe Benefits and Faculty

The growth of employee benefits in academe has closely paralleled their economy-wide growth. This study estimates a complete system describing the demand for benefits and wages using panel data on nearly 1500 institutions of higher learning. The demand for benefits is quite responsive both to changes in real income and to variations in the tax price of benefits. These conclusions are robust with respect to varying definitions of the sample aid of the tax price. They are not altered by estimates that account for unmeasured individual effects on demand. Simulations using the estimates suggest that the Tax Reform Act of 1986 sharply reduced the demand for benefits. Extrapolating the impact to the entire economy suggests that the annual flow of compensation shifted away from benefits by at least $9 billion.

Output-input stability and minimum-phase nonlinear systems

This paper introduces and studies the notion of output-input stability, which represents a variant of the minimum-phase property for general smooth nonlinear control systems. The definition of output-input stability does not rely on a particular choice of coordinates in which the system takes a normal form or on the computation of zero dynamics. In the spirit of the ``input-to-state stability'' philosophy, it requires the state and the input of the system to be bounded by a suitable function of the output and derivatives of the output, modulo a decaying term depending on initial conditions. The class of output-input stable systems thus defined includes all affine systems in global normal form whose internal dynamics are input-to-state stable and also all left-invertible linear systems whose transmission zeros have negative real parts. As an application, we explain how the new concept enables one to develop a natural extension to nonlinear systems of a basic result from linear adaptive control.Comment: Revised version, to appear in IEEE Transactions on Automatic Control. See related work in http://www.math.rutgers.edu/~sontag and http://black.csl.uiuc.edu/~liberzo

The relationship between EUV dimming and coronal mass ejections

Aims. There have been many studies of extreme-ultraviolet (EUV) dimming in association with coronal mass ejection (CME) onsets. However, there has never been a thorough statistical study of this association, covering appropriate temperature ranges. Thus, we make use of a large campaign database utilising the Coronal Diagnostic Spectrometer (CDS) and the Large Angle and Spectrometric COronagraph (LASCO) both on the SOlar and Heliospheric Observatory (SOHO) to associate dimming events detected at 1 and 2 million K with CME activity. The aim is to confirm whether the dimming-CME association is real or not. This in turn will confirm whether special attention should be paid to the EUV dimming in the pre-eruption and eruption periods to study the CME onset process itself. Methods. The CDS CME onset campaign data for Mg IX and FE XVI observations on the solar limb are used to compare to LASCO event lists over a period from 1998 to 2005. Dimming events are identified and the physical extent explored, whilst comparing the events to overlying CME activity. Results. For the identified dimming regions we have shown strong associations with CME onsets, with up to 55% of the dimming events being associated with CME activity. This is compared to the random case where up to 47% of the dimming regions are expected to be associated with CMEs. We have also shown that up to 84% of CMEs associated with our data can be tracked back to dimming regions. This compares to a random case of up to 58%. Conclusions. These results confirm the CME-EUV dimming association, using a statistical analysis for the first time. We discuss the repercussions for the study of CME onsets, i.e. analysis of the dimming regions and the periods up to such dimming may be key to understanding the pre-CME onset plasma processes. The results stress that one emission line may not be sufficient for associating dimming regions with CMEs

Political Ambition and Legislative Behavior in the European Parliament

Members of the European Parliament (MEP) typically follow one of two career paths, either advancing within the European Parliament itself or returning to higher office in their home states. We argue that these different ambitions condition legislative behavior. Specifically, MEPs seeking domestic careers defect from group-leadership votes more frequently and oppose legislation that expands the purview of supranational institutions. We show how individual, domestic-party, and national level variables shape the careers available to MEPs and, in turn, their voting choices. To test the argument, we analyze MEPs' roll-call voting behavior in the 5th session of the EP (1999-2004) using a random effects model that captures idiosyncrasies in voting behavior across both individual MEPs and specific roll-call votes.published or submitted for publicationnot peer reviewe

Altering the stability of the Cdc8 overlap region modulates the ability of this tropomyosin to bind cooperatively to actin and regulate myosin.

Tropomyosin (Tm) is an evolutionarily conserved ?-helical coiled-coil protein, dimers of which form end-to-end polymers capable of associating with and stabilising actin-filaments and regulate myosin function. The fission yeast, Schizosaccharomyces pombe, possesses a single essential Tm, Cdc8, which can be acetylated on its amino terminal methionine to increase its affinity for actin and enhance its ability to regulate myosin function. We have designed and generated a number of novel Cdc8 mutant proteins with amino terminal substitutions to explore how stability of the Cdc8-polymer overlap region affects the regulatory function of this Tm. By correlating the stability of each protein, its propensity to form stable polymers, its ability to associate with actin and to regulate myosin, we have shown the stability of the amino terminal of the Cdc8 ?-helix is crucial for Tm function. In addition we have identified a novel Cdc8 mutant with increased amino-terminal stability, dimers of which are capable of forming Tm-polymers significantly longer than the wild-type protein. This protein had a reduced affinity for actin with respect to wild type, and was unable to regulate actomyosin interactions. The data presented here are consistent with acetylation providing a mechanism for modulating the formation and stability of Cdc8 polymers within the fission yeast cell. The data also provide evidence for a mechanism in which Tm dimers form end-to-end polymers on the actin-filament, consistent with a cooperative model for Tm binding to actin