Miami University

About: Miami University is a education organization based out in Oxford, Ohio, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 9949 authors who have published 19598 publications receiving 568410 citations. The organization is also known as: Miami of Ohio & Miami-Ohio.

Predicting short-term stock prices using ensemble methods and online data sources

Abstract: With the ubiquity of the Internet, platforms such as: Google, Wikipedia and the like can provide insights pertaining to firms’ financial performance as well as capture the collective interest of traders through search trends, number of web page visitors and/or financial news sentiment. Information emanating from these platforms can significantly affect, or be affected by, changes in the stock market. The overarching goal of this paper is to develop a financial expert system that incorporates these features to predict short term stock prices. Our expert system is comprised of two main modules: a knowledge base and an artificial intelligence (AI) platform. The “knowledge base” for our expert system captures: (a) historical stock prices; (b) several well-known technical indicators; (c) counts and sentiment scores of published news articles for a given stock; (d) trends in Google searches for the given stock ticker; and (e) number of unique visitors for pertinent Wikipedia pages. Once the data is collected, we use a structured approach for data preparation. Then, the AI platform trains four machine learning ensemble methods: (a) a neural network regression ensemble; (b) a support vector regression ensemble; (c) a boosted regression tree; and (d) a random forest regression. In the cross-validation phase, the AI platform picks the “best” ensemble for a given stock. To evaluate the efficacy of our expert system, we first present a case study based on the Citi Group stock ($C) with data collected from 01/01/2013 - 12/31/2016. We show the expert system can predict the 1-day ahead $C stock price with a mean absolute percent error (MAPE) ≤ 1.50% and the 1–10 day ahead with a MAPE ≤ 1.89%, which is better than the reported results in the literature. We show that the use of features extracted from online sources does not substitute the traditional financial metrics, but rather supplements them to improve upon the prediction performance of machine learning based methods. To highlight the utility and generalizability of our expert system, we predict the 1-day ahead price of 19 additional stocks from different industries, volatilities and growth patterns. We report an overall mean for the MAPE statistic of 1.07% across our five different machine learning models, including a MAPE of under 0.75% for 18 of the 19 stocks for the best ensemble (boosted regression tree).

New discoveries of Australopithecus at Maka in Ethiopia

Abstract: The taxonomy of Australopithecus afarensis, the oldest known hominid species, has been a matter of debate since its description in 1978 (ref. 1). Some authorities regard all specimens assigned to A. afarensis as belonging to a single taxon whereas others regard the Tanzanian and Ethiopian specimens as each representing a different species. Further controversy surrounds the issues of sexual dimorphism and locomotion among these hominids. Resolution of these problems would shed light on hominid phylogeny in general and on the ancestry of later Australopithecus and Homo. Fossils discovered in the Afar of Ethiopia in 1990 constitute the first major addition to the 3-4 million year (Myr) hominid record since the 1970s. We report here the discovery of new fossils from Maka, dated to 3.4 Myr ago, which provide powerful support for the interpretation of A. afarensis as a single, ecologically diverse, sexually dimorphic, bipedal Pliocene primate species whose known range encompassed Ethiopia and Tanzania.

Theory of constraints and linear programming: a comparison

Abstract: SUMMARY Since initial work done by Goldratt in the mid-1980s and as the concepts related to the theory of constraints (TOC) have become more developed, many have concluded that the TOC approach offers nothing in addition to what can be accomplished through linear programming (LP). Through the use of an example, this paper compares TOC to LP and clarifies the differences surrounding the TOC philosophy and the LP technique

Diamonds in Ophiolites

Abstract: Ophiolites are a newly documented host of diamonds on Earth. Abundant diamonds have indeed been separated from peridotites and chromitites of ophiolites in China, Myanmar, and Russia. In addition, diamond grains have recently been discovered in chromite from the Cretaceous Luobusa ophiolite (Tibet) and the early Paleozoic Ray-Iz ophiolite (polar Urals, Russia). These diamonds are accompanied by a wide range of highly reduced minerals, such as Ni–Mn–Co alloys, Fe–Si and Fe–C phases, and moissanite (SiC); these have been found as either mineral separates or inclusions in diamonds and indicate growth under superreducing conditions. The diamond-bearing chromite grains likely formed near the mantle transition zone and were then brought to shallow levels in the upper mantle to form podiform chromitites in oceanic lithosphere. Because these diamond grains occur widely in peridotites and chromitites of many ophiolites, we refer to them as ophiolite-hosted diamonds. It is possible that such diamonds may be common in the upper oceanic mantle.

"Nothing really matters": Emotional numbing as a link between trauma exposure and callousness in delinquent youth

Abstract: This study investigated the interrelations among trauma exposure, emotional numbing, and callous-unemotional traits in a sample of 276 youth (68 girls and 208 boys) recruited from 2 juvenile detention centers. Youth completed interview measures of trauma exposure and betrayal trauma, as well as self-report measures of emotional numbing and callous-unemotional traits. Results of path analyses using nonparametric bootstrapping procedures indicated findings consistent with the hypothesis that the association between trauma exposure and callous-unemotional traits was mediated by the general numbing of emotions, R(2) = .40, and also specifically by numbing of sadness, R(2) = .27. In addition, further analyses indicated that numbing of fear, R(2) = .18, and sadness, R(2) = .26, statistically mediated the relations to callous-unemotional traits only for those traumatic experiences involving betrayal. Gender was not found to moderate these effects. Language: en