A Simplified Approach to Understanding the Kalman Filter Technique

The Kalman filter is a time series estimation algorithm that is applied extensively in the field of engineering and recently (relative to engineering) in the field of finance and economics. However, presentations of the technique are somewhat intimidating despite the relative ease of generating the algorithm. This article presents the Kalman filter in a simplified manner and produces an example of an application of the algorithm in Excel. This scaled-down version of the Kalman filter can be introduced in the (advanced) undergraduate classroom as well as the graduate classroom

QCD and QED dynamics of the EMC effect

Applying exact QCD sum rules for the baryon charge and energy-momentum we demonstrate that if nucleons are the only degrees of freedom of nuclear wave function, the structure function of a nucleus would be the additive sum of the nucleon distributions at the same Bjorken x = AQ^2/2(p_Aq)< 0.5 up to very small Fermi motion corrections if x>0.05. Thus the difference of the EMC ratio from one reveals the presence of non-nucleonic degrees of freedom in nuclei. Using exact QCD sum rules we show that the ratio R_A(x_p,Q^2) used in experimental studies, where x_p = Q^2/2q_0 m_p deviates from one even if a nucleus consists of nucleons with small momenta only. Use of the Bjorken x leads to additional decrease of R_A(x,Q^2) as compared to the x_p plots. Coherent contribution of equivalent photons into photon component of parton wave function of a nucleus unambiguously follows from Lorentz transformation of the rest frame nucleus Coulomb field. For A~200 photons carry ~0.0065 fraction of the light momentum of nucleus almost compensates the difference between data analysis in terms of Bjorken x and x_p. Different role of higher twist effects for Q^2 probed at electron and muon beams is emphasized. Direct observations of large and predominantly nucleonic short-range correlations in nuclei pose a serious challenge for most of the models of the EMC effect for x>0.6. The data are consistent with a scenario in which the hadronic EMC effect reflects fluctuations of inter nucleon interaction due to fluctuations of color distribution in the interacting nucleons. The dynamic realization of this scenario is the model in which the 3q (3qg) configurations with x > 0.5 parton have a weaker interaction with nearby nucleons, leading to suppression of such configurations giving a right magnitude of the EMC effect. The directions for the future studies and challenging questions are outlined.Comment: The sign in the relation of x_Bj and x_p is corrected and the following discussion is adjusted accordingly. Discussion of the higher twist effects is adde

Deciphering Consumer Commitment: Exploring the Dual Influence of Self-Brand and Self-Group Relationships

Consumer-brand relationships are highly valued as brand-committed consumers are thought to deliver many positive outcomes for affiliated brands. However, in addition to connections between individuals and brands, consumer-brand relationships also involve relationships between individuals and other brand users. Little attention has been given to the potential consequences associated with commitment to other brand users as compared to the brand itself. Therefore, our framework establishes two distinct types of consumer-brand relationships (i.e., self-brand relationships vs. self-group relationships) that differentially influence brand commitment versus group commitment, leading to contrasting effects on both desirable and undesirable brand outcomes. Specifically, our studies illuminate that while brand commitment is largely associated with favorable brand-related outcomes, group commitment does not protect against brand switching and is negatively related to willingness to pay price premiums and positive word-of-mouth. Our main contribution is uncovering how consumer-brand relationships face tradeoffs between brand and group attachments, whereby commitment provides both conditional benefits as well as unintended consequences

A transmission model for Salmonella in grower-finisher pigs

This paper presents a model describing the dynamic transmission of Salmonella Typhimurium between pigs on a typical, British pig grower-finisher farm. A modified Reed-Frost discrete-time model was used to estimate the probability of infection for susceptible pigs

Optimisation of pooled faecal samples for the isolation fo Salmonella from finisher pigs in GB.

Pooled pen floor faecal sampling represents a simple and non-invasive method to measure Salmonella infection in pigs. We extended an existing model of the sensitivity of detection of Salmonella in individual samples to create a mathematical model of the sensitivity of pooled sampling

Thalamic activity that drives visual cortical plasticity

Manipulations of activity in one retina can profoundly affect binocular connections in the visual cortex. Retinal activity is relayed to the cortex by the dorsal lateral geniculate nucleus (dLGN). We compared the qualities and amount of activity in the dLGN following monocular eyelid closure and monocular retinal inactivation in awake mice. Our findings substantially alter the interpretation of previous studies and define the afferent activity patterns that trigger cortical plasticity.National Eye InstituteNational Institute of Neurological Disorders and Stroke (U.S.) (National Research Service Award fellowship