The Anomalous Magnetic Moments of the Electron and the Muon - Improved QED Predictions Using Pade Approximants

We use Pade Approximants to obtain improved predictions for the anomalous magnetic moments of the electron and the muon. These are needed because of the very precise experimental values presently obtained for the electron, and soon to be obtained at BNL for the muon. The Pade prediction for the QED contribution to the anomalous magnetic moment of the muon differs significantly from the naive perturbative prediction.Comment: 8 pages (LateX); SLAC-PUB-6670, CERN-TH-7451/94, TAUP-2201-94, OSU-RN-393/94. Typo correcte

Population response to climate change: linear vs. non-linear modeling approaches

BACKGROUND: Research on the ecological consequences of global climate change has elicited a growing interest in the use of time series analysis to investigate population dynamics in a changing climate. Here, we compare linear and non-linear models describing the contribution of climate to the density fluctuations of the population of wolves on Isle Royale, Michigan from 1959 to 1999. RESULTS: The non-linear self excitatory threshold autoregressive (SETAR) model revealed that, due to differences in the strength and nature of density dependence, relatively small and large populations may be differentially affected by future changes in climate. Both linear and non-linear models predict a decrease in the population of wolves with predicted changes in climate. CONCLUSIONS: Because specific predictions differed between linear and non-linear models, our study highlights the importance of using non-linear methods that allow the detection of non-linearity in the strength and nature of density dependence. Failure to adopt a non-linear approach to modelling population response to climate change, either exclusively or in addition to linear approaches, may compromise efforts to quantify ecological consequences of future warming

Introduction to Advances in Teaching and Learning Technologies Minitrack

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Formal property titles or more? Perspectives from Ghana's financial institutions

The dead capital thesis of de Soto has raised a lot of debate on the  relationship between formal property titles and access to credit. Various authors have argued that overconcentration of policy efforts on providing formal property titles could be overly simplistic. The argument has largely been made along the logic espoused in the ‘dead capital theses’. However, more than a formal title is required to access credit from formal financial institutions by small businesses. The aim of this paper is to examine the critical factors inhibiting credit access by SMEs and assess the relative  importance of formal titles amongst the other factors responsible for the financing gap. Surveys were conducted amongst officials of various financial institutions using structured questionnaires. The data was analysed using factor analysis. The results show that formal lenders perceive the absence of formal property titles to be a factor inhibiting SMEs credit access albeit the exact effect is very marginal relative to other factors.Keywords: Access to credit; Dead capital; Financial institutions; Formalproperty title; SMEs

Evaluating eukaryotic secreted protein prediction

BACKGROUND: Improvements in protein sequence annotation and an increase in the number of annotated protein databases has fueled development of an increasing number of software tools to predict secreted proteins. Six software programs capable of high throughput and employing a wide range of prediction methods, SignalP 3.0, SignalP 2.0, TargetP 1.01, PrediSi, Phobius, and ProtComp 6.0, are evaluated. RESULTS: Prediction accuracies were evaluated using 372 unbiased, eukaryotic, SwissProt protein sequences. TargetP, SignalP 3.0 maximum S-score and SignalP 3.0 D-score were the most accurate single scores (90–91% accurate). The combination of a positive TargetP prediction, SignalP 2.0 maximum Y-score, and SignalP 3.0 maximum S-score increased accuracy by six percent. CONCLUSION: Single predictive scores could be highly accurate, but almost all accuracies were slightly less than those reported by program authors. Predictive accuracy could be substantially improved by combining scores from multiple methods into a single composite prediction

The Density Profiles of Massive, Relaxed Galaxy Clusters. I. The Total Density Over Three Decades in Radius

Clusters of galaxies are excellent locations to probe the distribution of baryons and dark matter (DM) over a wide range of scales. We study a sample of seven massive, relaxed galaxy clusters with centrally-located brightest cluster galaxies (BCGs) at z=0.2-0.3. Using the observational tools of strong and weak gravitational lensing, combined with resolved stellar kinematics within the BCG, we measure the total radial density profile, comprising both dark and baryonic matter, over scales of ~3-3000 kpc. Lensing-derived mass profiles typically agree with independent X-ray estimates within ~15%, suggesting that departures from hydrostatic equilibrium are small and that the clusters in our sample (except A383) are not strongly elongated along the line of sight. The inner logarithmic slope gamma_tot of the total density profile measured over r/r200=0.003-0.03, where rho_tot ~ r^(-gamma_tot), is found to be nearly universal, with a mean = 1.16 +- 0.05 (random) +0.05-0.07 (systematic) and an intrinsic scatter of < 0.13 (68% confidence). This is further supported by the very homogeneous shape of the observed velocity dispersion profiles, obtained via Keck spectroscopy, which are mutually consistent after a simple scaling. Remarkably, this slope agrees closely with numerical simulations that contain only dark matter, despite the significant contribution of stellar mass on the scales we probe. The Navarro-Frenk-White profile characteristic of collisionless cold dark matter is a better description of the total mass density at radii >~ 5-10 kpc than that of dark matter alone. Hydrodynamical simulations that include baryons, cooling, and feedback currently provide a poorer match. We discuss the significance of our findings for understanding the assembly of BCGs and cluster cores, particularly the influence of baryons on the inner DM halo. [abridged]Comment: Updated to matched the published version in Ap