Associative memory in gene regulation networks

The pattern of gene expression in the phenotype of an organism is determined in part by the dynamical attractors of the organism’s gene regulation network. Changes to the connections in this network over evolutionary time alter the adult gene expression pattern and hence the fitness of the organism. However, the evolution of structure in gene expression networks (potentially reflecting past selective environments) and its affordances and limitations with respect to enhancing evolvability is poorly understood in general. In this paper we model the evolution of a gene regulation network in a controlled scenario. We show that selected changes to connections in the regulation network make the currently selected gene expression pattern more robust to environmental variation. Moreover, such changes to connections are necessarily ‘Hebbian’ – ‘genes that fire together wire together’ – i.e. genes whose expression is selected for in the same selective environments become co-regulated. Accordingly, in a manner formally equivalent to well-understood learning behaviour in artificial neural networks, a gene expression network will therefore develop a generalised associative memory of past selected phenotypes. This theoretical framework helps us to better understand the relationship between homeostasis and evolvability (i.e. selection to reduce variability facilitates structured variability), and shows that, in principle, a gene regulation network has the potential to develop ‘recall’ capabilities normally reserved for cognitive systems

Non-cognitive Predictors of Students\u27 Achievement

The purpose of this study was to examine the predictive value of ACT scores and personality characteristics as they pertain to college GPA and quiz scores on three upper-level psychology classes. Male and female college students (N=82) from three upper-level psychology classes at the University of Missouri-Rolla were asked to fill out a questionnaire surveying, among other demographic information, ACT score and college GPA, and a personality survey to measure levels of the Big Five personality traits. Our results support our hypothesis that ACT scores will be positively correlated with GPA and quiz performance, as well as our hypotheses that the personality traits Conscientiousness is positively correlated with college GPA and quiz performance and that Neuroticism is negatively correlated with college GPA and quiz performance

Towards Real-Time, Country-Level Location Classification of Worldwide Tweets

In contrast to much previous work that has focused on location classification of tweets restricted to a specific country, here we undertake the task in a broader context by classifying global tweets at the country level, which is so far unexplored in a real-time scenario. We analyse the extent to which a tweet's country of origin can be determined by making use of eight tweet-inherent features for classification. Furthermore, we use two datasets, collected a year apart from each other, to analyse the extent to which a model trained from historical tweets can still be leveraged for classification of new tweets. With classification experiments on all 217 countries in our datasets, as well as on the top 25 countries, we offer some insights into the best use of tweet-inherent features for an accurate country-level classification of tweets. We find that the use of a single feature, such as the use of tweet content alone -- the most widely used feature in previous work -- leaves much to be desired. Choosing an appropriate combination of both tweet content and metadata can actually lead to substantial improvements of between 20\% and 50\%. We observe that tweet content, the user's self-reported location and the user's real name, all of which are inherent in a tweet and available in a real-time scenario, are particularly useful to determine the country of origin. We also experiment on the applicability of a model trained on historical tweets to classify new tweets, finding that the choice of a particular combination of features whose utility does not fade over time can actually lead to comparable performance, avoiding the need to retrain. However, the difficulty of achieving accurate classification increases slightly for countries with multiple commonalities, especially for English and Spanish speaking countries.Comment: Accepted for publication in IEEE Transactions on Knowledge and Data Engineering (IEEE TKDE

Evaluating CPB's published GDP growth forecasts; a comparison with individual and pooled VAR based forecasts

We compare the accuracy of our published GDP growth forecasts from our large macro model, SAFFIER, to those produced by VAR based models using both classical and Bayesian estimation techniques. We employ a data driven methodology for selecting variables to include in our VAR models and we find that a randomly selected classical VAR model performs worse in most cases than the Bayesian equivalent, which performs worse than our published forecasts in most cases. However, when we pool forecasts across many VARs we can produce more accurate forecasts than we published. A review of the literature suggests that forecast accuracy is likely irrelevant for the non-forecasting activities the model is used for at CPB because they are fundamentally different activities.

Epaulets in Golden Eagle Plumages in Western Montana

An uncommon plumage characteristic of North American Golden Eagles (Aquila chrysaetos) is the epaulet, a white feather or feathers at the shoulder, often symmetrical on both sides in appearance. The size and shape of an epaulet varies by individual. This characteristic is mentioned within the literature, but is not noted how it is reflected within a population. We have observed epaulets in 17 out of 102 (16.6%) individual Golden Eagles with at least one epaulet in western Montana since 2012. Of these individuals, 13 (76.4%) were observed on the Rocky Mountain Front while on migration, and 4 (23.6%) were observed on wintering grounds in the Bitterroot Valley, Montana. Epaulets have been observed on both male and female individuals, and on both sub-adult and adult aged birds. This plumage characteristic should continue to be recorded in Golden Eagles for a better estimate of rate of occurrence within a population

Harvest index of lupins, Direct drilling on sandplain soils.

Chemicals to improve pod setting in Lupins (Small plots), 89C23, 89GE74, Chemicals to improve pod setting in Lupins (Large plots) 89GE72, 89GE75