Automatic document classification of biological literature

Background: Document classification is a wide-spread problem with many applications, from organizing search engine snippets to spam filtering. We previously described Textpresso, a text-mining system for biological literature, which marks up full text according to a shallow ontology that includes terms of biological interest. This project investigates document classification in the context of biological literature, making use of the Textpresso markup of a corpus of Caenorhabditis elegans literature. Results: We present a two-step text categorization algorithm to classify a corpus of C. elegans papers. Our classification method first uses a support vector machine-trained classifier, followed by a novel, phrase-based clustering algorithm. This clustering step autonomously creates cluster labels that are descriptive and understandable by humans. This clustering engine performed better on a standard test-set (Reuters 21578) compared to previously published results (F-value of 0.55 vs. 0.49), while producing cluster descriptions that appear more useful. A web interface allows researchers to quickly navigate through the hierarchy and look for documents that belong to a specific concept. Conclusions: We have demonstrated a simple method to classify biological documents that embodies an improvement over current methods. While the classification results are currently optimized for Caenorhabditis elegans papers by human-created rules, the classification engine can be adapted to different types of documents. We have demonstrated this by presenting a web interface that allows researchers to quickly navigate through the hierarchy and look for documents that belong to a specific concept

A Survey of Interface Tracking Methods in Multi-phase Fluid Visualization

A central feature that scientists are interested in is the dynamics of fluid interfaces or the so called material boundaries in multi-fluid simulation . Visualization techniques for capturing fluid interface are based on one of about three basic algorithms. In this paper, we give a survey of the existing interface tracking algorithms, including backgrounds, terms, procedures as well as pointers to details and further reading. We also provide a glance at the mathematical fundamentals of multi-fluid dynamics for scientists who are interested in understanding the underlying math and physics of multi-phase fluid simulation

Thermal Reflector System Design and Testing for the Microwave Anisotropy Probe

Scheduled for a June 2001 launch, the Microwave Anisotropy Probe’s (MAP) mission is to study in detail the cosmic microwave background radiation temperature fluctuations of the universe. The cosmic microwave background is the remnant afterglow of the Big Bang, and the tiny temperature differences from place to place on the sky provides a wealth of information about the basic nature of our universe. The observatory consists of dual back-to-back Gregorian optics and dual differential pseudo-correlation microwave radiometers. MAP will scan the sky over a 22 to 90 Ghz spectrum during a 26 month mission at L2. To achieve the necessary dimensional stability and stringent total weight limits, the Thermal Reflector System (TRS) consists of dual primary and secondary lightweight composite reflectors mounted to a lightweight but rigid composite truss structure. Design features include the use of lightweight graphite spread fabric and honeycomb core for the reflector shells and stiffening structure, and a bonded mortise and tenon truss structure using two complementary composite materials. Qualification of the TRS included in-situ photogrammetry measurements while at 40K and 370K, sine burst and sine sweep dynamic loading, and acoustic excitation. Materials employed, coupon test data, design and construction, and qualification testing will be discussed

Effectiveness of folic acid fortified flour for prevention of neural tube defects in a high risk region

Despite efforts to tackle folate deficiency and Neural Tube Defects (NTDs) through folic acid fortification, its implementation is still lacking where it is needed most, highlighting the need for studies that evaluate the effectiveness of folic acid fortified wheat flour in a poor, rural, high-risk, NTD region of China. One of the most affected regions, Shanxi Province, was selected as a case study. A community intervention was carried out in which 16,648 women of child-bearing age received fortified flour (eight villages) and a control group received ordinary flour (three villages). NTD birth prevalence and biological indicators were measured two years after program initiation at endline only. The effect on the NTD burden was calculated using the disability-adjusted life years (DALYs) method. In the intervention group, serum folate level was higher than in the control group. NTDs in the intervention group were 68.2% lower than in the control group (OR = 0.313, 95% CI = 0.207-0473, p < 0.001). In terms of DALYs, burden in intervention group was approximately 58.5% lower than in the control group. Flour fortification was associated with lower birth prevalence and burden of NTDs in economically developing regions with a high risk of NTDs. The positive findings confirm the potential of fortification when selecting an appropriate food vehicle and target region. As such, this study provides support for decision makers aiming for the implementation of (mandatory) folic acid fortification in China

Asymptotics and Scattering for Wave-Klein-Gordon Systems

We study the coupled wave-Klein-Gordon systems, introduced by LeFloch-Ma and then Ionescu-Pausader, to model the nonlinear effects from the Einstein-Klein-Gordon equation in harmonic coordinates. We first go over a slightly simplified version of global existence based on LeFloch-Ma, and then derive the asymptotic behavior of the system. The asymptotics of the Klein-Gordon field consist of a modified phase times a homogeneous function, and the asymptotics of the wave equation consist of a radiation field in the wave zone and an interior homogeneous solution coupled to the Klein-Gordon asymptotics. We then consider the inverse problem, the scattering from infinity. We show that given the type of asymptotic behavior at infinity, there exist solutions of the system that present the exact same behavior.Comment: Corrected typos and improved expositio