Key Ingredient (key + ingredient)

Distribution by Scientific Domains

Selected Abstracts

The State-by-State Economic Impacts of the 2002 Shutdown of the Los Angeles,Long Beach Ports

ABSTRACT In previous research, the economic impacts of temporary shutdowns of the Los Angeles,Long Beach harbors were simulated after a hypothetical terrorist attack, applying the National Interstate Economic Model to estimate state-by-state as well as interindustry impacts. However, the unpredictable characteristic of terrorist attacks might not be applicable to the case of a ports shutdown such as the one caused by the lockout of September,October 2002. Market participants can be expected to have contingency plans based on anticipations of a strike or shutdown. Can we identify any of these in terms of the use of alternate ports, in terms of alternate modes or even alternate time periods? The purpose of this study is to examine these questions. The approach is elaborated by testing for the possible effects of trade diversion to other West Coast ports, transportation modes, and intertemporal substitutions. We use data from WISERTrade describing commodity-specific trade for the major West Coast ports before, during, and after the 11-day shutdown of the fall of 2002. Shippers' ability to divert trade is a key ingredient in the economy's ability to withstand attacks and disruptions. The work estimates the impacts on 47 industrial sectors across 50 states (and the District of Columbia). [source]

The Lambert Code: Can We Define Best Practice?

Michael Shattock
The article explores the proposals put forward in the Lambert Report for reforms in university governance. It compares the recommendation for a Code with the analogue Combined Code which regulates corporate governance in companies and draws a distinction between attempts, from the Cadbury Report in 1992 to the Higgs Review in 2003, to create board structures which will reduce the prospect of misgovernance, and the underlying aim of Lambert to improve university performance through governance change. It argues that analogies between university governing bodies and company boards are misleading and that university governing bodies, on their own, are almost by definition unable to fulfill the criteria of an ,effective board' laid down in the DTI Report on TransTec. It suggests that a Guide on Governance which encourages institutional self determination is a better basis for sustaining institutional autonomy, which is a key ingredient to encouraging high levels of performance, than a Government backed Code which risks reducing institutional diversity and cutting across existing legal instruments. It concludes that the proposed Code is a distraction from serious consideration of what factors encourage improved institutional performance. [source]

Full evolution of low-mass white dwarfs with helium and oxygen cores

J. A. Panei
ABSTRACT We study the full evolution of low-mass white dwarfs with helium and oxygen cores. We revisit the age dichotomy observed in many white dwarf companions to millisecond pulsar on the basis of white dwarf configurations derived from binary evolution computations. We evolve 11 dwarf sequences for helium cores with final masses of 0.1604, 0.1869, 0.2026, 0.2495, 0.3056, 0.3333, 0.3515, 0.3844, 0.3986, 0.4160 and 0.4481 M,. In addition, we compute the evolution of five sequences for oxygen cores with final masses of 0.3515, 0.3844, 0.3986, 0.4160 and 0.4481 M,. A metallicity of Z= 0.02 is assumed. Gravitational settling, chemical and thermal diffusion are accounted for during the white dwarf regime. Our study reinforces the result that diffusion processes are a key ingredient in explaining the observed age and envelope dichotomy in low-mass helium-core white dwarfs, a conclusion we arrived at earlier on the basis of a simplified treatment for the binary evolution of progenitor stars. We determine the mass threshold where the age dichotomy occurs. For the oxygen white dwarf sequences, we report the occurrence of diffusion-induced, hydrogen-shell flashes, which, as in the case of their helium counterparts, strongly influence the late stages of white dwarf cooling. Finally, we present our results as a set of white dwarf mass,radius relations for helium and oxygen cores. [source]

Estimating the spectral indices of correlated astrophysical foregrounds by a second-order statistical approach

A. Bonaldi
ABSTRACT We present the first tests of a new method, the correlated component analysis (CCA) based on second-order statistics, to estimate the mixing matrix, a key ingredient to separate astrophysical foregrounds superimposed to the Cosmic Microwave Background (CMB). In the present application, the mixing matrix is parametrized in terms of the spectral indices of Galactic synchrotron and thermal dust emissions, while the free,free spectral index is prescribed by basic physics, and is thus assumed to be known. We consider simulated observations of the microwave sky with angular resolution and white stationary noise at the nominal levels for the Planck satellite, and realistic foreground emissions, with a position-dependent synchrotron spectral index. We work with two sets of Planck frequency channels: the low-frequency set, from 30 to 143 GHz, complemented with the Haslam 408 MHz map, and the high-frequency set, from 217 to 545 GHz. The concentration of intense free,free emission on the Galactic plane introduces a steep dependence of the spectral index of the global Galactic emission with Galactic latitude, close to the Galactic equator. This feature makes difficult for the CCA to recover the synchrotron spectral index in this region, given the limited angular resolution of Planck, especially at low frequencies. A cut of a narrow strip around the Galactic equator (|b| < 3°), however, allows us to overcome this problem. We show that, once this strip is removed, the CCA allows an effective foreground subtraction, with residual uncertainties inducing a minor contribution to errors on the recovered CMB power spectrum. [source]

The origin and formation of cuspy density profiles through violent relaxation of stellar systems

S. Hozumi
It is shown that the cuspy density distributions observed in the cores of elliptical galaxies can be realized by dissipationless gravitational collapse. The initial models consist of power-law density spheres such as ,,r,1 with anisotropic velocity dispersions. Collapse simulations are carried out by integrating the collisionless Boltzmann equation directly, on the assumption of spherical symmetry. From the results obtained, the extent of constant density cores, formed through violent relaxation, decreases as the velocity anisotropy increases radially, and practically disappears for extremely radially anisotropic models. As a result, the relaxed density distributions become more cuspy with increasing radial velocity anisotropy. It is thus concluded that the velocity anisotropy could be a key ingredient for the formation of density cusps in a dissipationless collapse picture. The velocity dispersions increase with radius in the cores according to the nearly power-law density distributions. The power-law index, n, of the density profiles, defined as ,,r,n, changes from n,2.1 at intermediate radii to a shallower power than n,2.1 toward the centre. This density bend can be explained from our postulated local phase-space constraint that the phase-space density accessible to the relaxed state is determined at each radius by the maximum phase-space density of the initial state. [source]

Numerical methods for palindromic eigenvalue problems: Computing the anti-triangular Schur form

D. Steven Mackey
Abstract We present structure-preserving numerical methods for the eigenvalue problem of complex palindromic pencils. Such problems arise in control theory, as well as from palindromic linearizations of higher degree palindromic matrix polynomials. A key ingredient of these methods is the development of an appropriate condensed form,the anti-triangular Schur form. Ill-conditioned problems with eigenvalues near the unit circle, in particular near ±1, are discussed. We show how a combination of unstructured methods followed by a structured refinement can be used to solve such problems accurately. Copyright © 2008 John Wiley & Sons, Ltd. [source]

What can the age composition of a population tell us about the age composition of its out-migrants?

Jani S. Little
Abstract Preliminary findings show that the age structure of a population can provide valuable information about the age composition of its out-migrants, and that this relationship can become a key ingredient in the proposed new method for estimating the age profile of out-migrants when accurate data are not available. The method relies on the Rogers-Castro model schedule to consistently and accurately represent age profiles of out-migration, and the results show that variation among these out-migration schedules can be captured by a typology based on a small set of clusters, or families of schedules. Membership of the clusters is then predicted from simple measures of population composition using discriminant function analysis. The investigation is based on data for US states, CMSAs, MSAs and non-metropolitan counties, and their outflows of migrants between 1995 and 2000. The measures of population age composition come from official 1995 intercensal age-specific population estimates for the same geographical units. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Testing monotone high-dimensional distributions,,

Ronitt Rubinfeld
Abstract A monotone distribution P over a (partially) ordered domain has P(y) , P(x) if y , x in the order. We study several natural problems of testing properties of monotone distributions over the n -dimensional Boolean cube, given access to random draws from the distribution being tested. We give a poly(n)-time algorithm for testing whether a monotone distribution is equivalent to or , -far (in the L1 norm) from the uniform distribution. A key ingredient of the algorithm is a generalization of a known isoperimetric inequality for the Boolean cube. We also introduce a method for proving lower bounds on testing monotone distributions over the n -dimensional Boolean cube, based on a new decomposition technique for monotone distributions. We use this method to show that our uniformity testing algorithm is optimal up to polylog(n) factors, and also to give exponential lower bounds on the complexity of several other problems (testing whether a monotone distribution is identical to or , -far from a fixed known monotone product distribution and approximating the entropy of an unknown monotone distribution). © 2008 Wiley Periodicals, Inc. Random Struct. Alg., 2009 [source]

Pairing mechanisms for binary stars

M.B.N. Kouwenhoven
Abstract Knowledge of the binary population in stellar groupings provides important information about the outcome of the star forming process in different environments. Binarity is also a key ingredient in stellar population studies and is a prerequisite to calibrate the binary evolution channels. In these proceedings we present an overview of several commonly used methods to pair individual stars into binary systems, which we refer to as the pairing function.Many pairing functions are frequently used by observers and computational astronomers, either for the mathematical convenience, or because they roughly describe the expected outcome of the star forming process. We discuss the consequences of each pairing function for the interpretation of observations and numerical simulations. The binary fraction and mass ratio distribution generally depend strongly on the selection of the range in primary spectral type in a sample. These quantities, when derived from a binary survey with a mass-limited sample of target stars, are thus not representative for the population as a whole. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Structure of human transthyretin complexed with bromophenols: a new mode of binding

Minakshi Ghosh
The binding of two organohalogen substances, pentabromophenol (PBP) and 2,4,6-tribromophenol (TBP), to human transthyretin (TTR), a thyroid hormone transport protein, has been studied by in vitro competitive binding assays and by X-­ray crystallography. Both compounds bind to TTR with high affinity, in competition with the natural ligand thyroxine (T4). The crystal structures of the TTR,PBP and TTR,TBP complexes show some unusual binding patterns for the ligands. They bind exclusively in the `reversed' mode, with their hydroxyl group pointing towards the mouth of the binding channel and in planes approximately perpendicular to that adopted by the T4 phenolic ring in a TTR,T4 complex, a feature not observed before. The hydroxyl group in the ligands, which was previously thought to be a key ingredient for a strong binding to TTR, does not seem to play an important role in the binding of these compounds to TTR. In the TTR,PBP complex, it is primarily the halogens which interact with the TTR molecule and therefore must account for the strong affinity of binding. The interactions with the halogens are smaller in number in TTR,TBP and there is a decrease in affinity, even though the interaction with the hydroxyl group is stronger than that in the TTR,PBP complex. [source]

Development and validation of a simple thin layer chromatographic method for the analysis of artemisinin in Artemisia annua L. plant extracts

Els Marchand
Abstract Owing to the development of parasite resistance to standard antimalarial treatments like chloroquine and sulfadoxine,pyrimethamine, the demand for Artemisia annua, a key ingredient for new and highly effective antimalarial drugs, is huge. Therefore selective and precise methods to determine the content of artemisinin in dry plant material and in raw impure extracts are needed. In this work a method is described for the clear separation and extraction of artemisinin from other plant components in the Artemisia annua L. plant by thin-layer chromatography (TLC). To obtain optimal extraction and recovery efficiency, several parameters were evaluted, including choice of extraction solvent, TLC plate type and sensitivity between UV and visible light. Method validation was performed on both the dry plant material and non-purified plant extracts. Toluene presented the highest extraction efficiency compared with petroleum ether, hexane and methanol. Reversed-phase plates showed more concentrated spots than normal-phase plates, while the sensitivity of the analysis in UV was comparable to that in visible light but less precise. The impure plant extracts were analyzed by both TLC and HPLC-UV at 215 nm and both methods met the requirements for linearity, selectivity, precision and accuracy. Hence, the proposed TLC method can easily be used for both qualitative and quantitative control of the raw plant extract in areas where advanced methods are scarce. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Morrison healthcare food services finds the key ingredients in operational excellence and great customer service

Andrea Seidl
Although its new initiative had met three-year goals for customer service and operating excellence in just two years, MHFS discovered it had uneven acceptance and implementation in the field. By making associate engagement, pride, and empowerment part of the new customer service strategy, MHFS is finally getting the results it wants. The organization appropriated talent and tools from other industries, got some outside help, and leveraged a powerful grass-roots program to make customer service relevant, compelling, and actionable for its mostly hourly field associates in 450 facilities. This article is printed by permission of Morrison Management Services. © 2007 Morrison Management Services. [source]

Therapist empathy and client anxiety reduction in motivational interviewing: "She carries with me, the experience"

Lynne E. Angus
Abstract In this article, we examine the use of motivational interviewing (MI) to treat generalized anxiety disorder (GAD) by means of case illustration that focuses on four categories drawn from the client's experience of the key ingredients in MI therapy. The case illustration, drawn from the York study on combining MI and cognitive behavior therapy in the treatment of GAD (uses the client's pre- and post-therapy narrative interviews) to arrive at categories representative of the client's experience of MI therapy. The results of the qualitative analysis highlight the key contributions to positive client outcomes and readiness for change in brief MI therapy for GAD. © 2009 Wiley Periodicals, Inc. J Clin Psychol: In Session 65: 1,12, 2009. [source]

Evaluation of a postgraduate training programme for community mental health practitioners

A. N. GAUNTLETT rmn bsc msc
Government guidelines on mental health care in England have considerable implications for the level of competency required by the mental health workforce. Implementing these changes requires the widespread introduction of training initiatives whose effectiveness in improving staff performance need to be demonstrated through programme evaluation. This exploratory study evaluates the impact of a 2-year mental health training programme by measuring skill acquisition and skill application, by identifying the key ingredients for facilitating the transfer of learning into practice, and by examining differences in outcome between the academic and the non-academic students. High skill acquisition and application was reported in the majority of interventions, however, low skill application was reported for some key interventions (assertive outreach, dual diagnosis). Statistically significant differences were found between student cohorts in one intervention for skill acquisition (crisis intervention) and two interventions for skill application (client strengths model; medication management). The main ingredients for facilitating transfer were found to be the credibility of the trainers and training alongside colleagues from their own workplace. Some of the possible explanatory factors for these findings are discussed. [source]

Ever since Clements: from succession to vegetation dynamics and understanding to intervention

S.T.A. Pickett
Abstract Introduction: This paper surveys a framework for vegetation dynamics to provide conceptual background for a series of papers addressing the role of vegetation dynamics in restoration. Richness of the foundation: Classical succession theory provides key ingredients for contemporary process studies of vegetation dynamics. The contemporary framework incorporates processes identified by Gleason and other critics of Clements' theory. Multiple causality: The Clementsian causes, when expanded to include interaction and to clarify net effects, accommodate those now recognized in vegetation dynamics. A mature successional framework: A hierarchical framework has emerged to evaluate the causes of vegetation dynamics. The framework identifies the general causes as site availability, species availability, and species performance. Differentials as drivers: Differentials in any of the three general causes can drive change in plant communities. Each general cause consists of specific mechanisms. A model template: To predict vegetation dynamics trajectories, models are required. A model template is presented to operationalize the hierarchical framework. Outcomes are contingent on species pools and environmental contexts and may be progressive or retrogressive. Relationships of frameworks: Other contemporary frameworks in biology relate to vegetation dynamics. Application to restoration: The vegetation dynamics framework is relevant to restoration through linkages with landscape ecology, disturbance ecology, competition, invasion ecology, and community assembly. The differentials of site availability, species availability, and species performance suggest the processes and strategies available for restoration. Conclusions: A synthetic framework of vegetation brings together the mechanisms required for successful restoration. [source]

Dirichlet duality and the nonlinear Dirichlet problem

F. Reese Harvey
We study the Dirichlet problem for fully nonlinear, degenerate elliptic equations of the form F(Hess u) = 0 on a smoothly bounded domain , , ,n. In our approach the equation is replaced by a subset F , Sym2(,n) of the symmetric n × n matrices with ,F , {F = 0}. We establish the existence and uniqueness of continuous solutions under an explicit geometric "F -convexity" assumption on the boundary ,,. We also study the topological structure of F -convex domains and prove a theorem of Andreotti-Frankel type. Two key ingredients in the analysis are the use of "subaffine functions" and "Dirichlet duality." Associated to F is a Dirichlet dual set F, that gives a dual Dirichlet problem. This pairing is a true duality in that the dual of F, is F, and in the analysis the roles of F and F, are interchangeable. The duality also clarifies many features of the problem including the appropriate conditions on the boundary. Many interesting examples are covered by these results including: all branches of the homogeneous Monge-Ampère equation over ,, ,, and ,; equations appearing naturally in calibrated geometry, Lagrangian geometry, and p -convex Riemannian geometry; and all branches of the special Lagrangian potential equation. © 2008 Wiley Periodicals, Inc. [source]

Three circles theorems for Schrödinger operators on cylindrical ends and geometric applications

Tobias H. Colding
We show that for a Schrödinger operator with bounded potential on a manifold with cylindrical ends, the space of solutions that grows at most exponentially at infinity is finite dimensional and, for a dense set of potentials (or, equivalently, for a surface for a fixed potential and a dense set of metrics), the constant function 0 is the only solution that vanishes at infinity. Clearly, for general potentials there can be many solutions that vanish at infinity. One of the key ingredients in these results is a three circles inequality (or log convexity inequality) for the Sobolev norm of a solution u to a Schrödinger equation on a product N × [0, T], where N is a closed manifold with a certain spectral gap. Examples of such N's are all (round) spheres ,,n for n , 1 and all Zoll surfaces. Finally, we discuss some examples arising in geometry of such manifolds and Schrödinger operators.© 2007 Wiley Periodicals, Inc. [source]