Forecast Bias Correction: A Second Order Method

The difference between a model forecast and actual observations is called forecast bias. This bias is due to either incomplete model assumptions and/or poorly known parameter values and initial/boundary conditions. In this paper we discuss a method for estimating corrections to parameters and initial conditions that would account for the forecast bias. A set of simple experiments with the logistic ordinary differential equation is performed using an iterative version of a first order version of our method to compare with the second order version of the method.Comment: 27 Pages, 3 figures, 8 table

Macroeconomic models and the yield curve: An assessment of the fit

Many have questioned the empirical relevance of the Calvo-Yun model. This paper adds a term structure to three widely studied macroeconomic models (Calvo-Yun, hybrid and Svensson). We back out from observations on the yield curve the underlying macroeconomic model that most closely matches the level, slope and curvature of the yield curve. With each model we trace the response of the yield curve to macroeconomic shocks. We assess the fit of each model against the observed behaviour of interest rates and find limited support for the Calvo-Yun model in terms of fit with the observed yield curve, we find some support for the hybrid model but the Svensson model performs best

Higher rank Wilson loops from a matrix model

We compute the circular Wilson loop of N=4 SYM theory at large N in the rank k symmetric and antisymmetric tensor representations. Using a quadratic Hermitian matrix model we obtain expressions for all values of the 't Hooft coupling. At large and small couplings we give explicit formulae and reproduce supergravity results from both D3 and D5 branes within a systematic framework.Comment: 1+18 pages. 1 figure. Typos correcte

The Anti-Gang Initiative in Detroit: An Aggressive Enforcement Approach to Gangs

Over the period of the intervention and operation of the-AGI project, there was a considerable decline in gun crimes in the target precincts, whereas the number of such offenses rose in the comparison precinct. This was particularly the case in the Ninth Precinct, where a statistically significant reduction of gun crimes occurred. Perhaps more importantly, this reduction represented 112 fewer gun crimes, and thus a commensurate fewer number of victims, per month in this precinct. Given the design of this study and available data, these results cannot be directly attributed to the intervention. However, there is a strong indication that these aggressive policing tactics contributed significantly to this meaningful reduction

Coupled ethical-epistemic analysis of public health research and practice: categorizing variables to improve population health and equity

The categorization of variables can stigmatize populations, which is ethically problematic and threatens the central purpose of public health: to improve population health and reduce health inequities. How social variables (e.g., behavioral risks for HIV) are categorized can reinforce stigma and cause unintended harms to the populations practitioners and researchers strive to serve.<p></p> Although debates about the validity or ethical consequences of epidemiological variables are familiar for specific variables (e.g., ethnicity), these issues apply more widely.<p></p> We argue that these tensions and debates regarding epidemiological variables should be analyzed simultaneously as ethical and epistemic challenges. We describe a framework derived from the philosophy of science that may be usefully applied to public health, and we illustrate its application.<p></p&gt

Abundances and Kinematics of Extremely Metal-Deficient, Carbon-Rich Halo Stars

Original paper can be found at: http://www.astrosociety.org/pubs/cs/286.html Copyright ASPTo study the possible nucleosynthetic backgrounds of extremely metal-deficient, carbon-rich (EMDC) stars, we have conducted high-resolution spectroscopy of 26 candidate objects selected from HK-survey stars with [Fe/H]? -2.0. The aims of the analysis are: (a) to calculate abundances for the targets, including the CNO- and neutron-capture elements; (b) to monitor the radial velocities of the survey targets and another 17 bona fide EMDC stars to search for binarity

Physician Income Expectations and Specialty Choice

In spite of the important role of income expectations in economics, economists know little about how people actually form these expectations. We use a unique data set that contains the explicit income expectations of medical students over a 25-year time period to examine how students form income expectations. We examine whether students condition their expectations on their own ability, contemporaneous physician income, and the ex post income of physicians in their medical school cohort. We then test whether a model that uses the students' explicit income expectations to predict their specialty choices has a better fit than a model that assumes income expectations are formed statically, and a model that bases income expectations on ex post income.