A Survey on Retrieval of Mathematical Knowledge

We present a short survey of the literature on indexing and retrieval of mathematical knowledge, with pointers to 72 papers and tentative taxonomies of both retrieval problems and recurring techniques.Comment: CICM 2015, 20 page

Mathematical practice, crowdsourcing, and social machines

The highest level of mathematics has traditionally been seen as a solitary endeavour, to produce a proof for review and acceptance by research peers. Mathematics is now at a remarkable inflexion point, with new technology radically extending the power and limits of individuals. Crowdsourcing pulls together diverse experts to solve problems; symbolic computation tackles huge routine calculations; and computers check proofs too long and complicated for humans to comprehend. Mathematical practice is an emerging interdisciplinary field which draws on philosophy and social science to understand how mathematics is produced. Online mathematical activity provides a novel and rich source of data for empirical investigation of mathematical practice - for example the community question answering system {\it mathoverflow} contains around 40,000 mathematical conversations, and {\it polymath} collaborations provide transcripts of the process of discovering proofs. Our preliminary investigations have demonstrated the importance of "soft" aspects such as analogy and creativity, alongside deduction and proof, in the production of mathematics, and have given us new ways to think about the roles of people and machines in creating new mathematical knowledge. We discuss further investigation of these resources and what it might reveal. Crowdsourced mathematical activity is an example of a "social machine", a new paradigm, identified by Berners-Lee, for viewing a combination of people and computers as a single problem-solving entity, and the subject of major international research endeavours. We outline a future research agenda for mathematics social machines, a combination of people, computers, and mathematical archives to create and apply mathematics, with the potential to change the way people do mathematics, and to transform the reach, pace, and impact of mathematics research.Comment: To appear, Springer LNCS, Proceedings of Conferences on Intelligent Computer Mathematics, CICM 2013, July 2013 Bath, U

Oral tongue cancer gene expression profiling: Identification of novel potential prognosticators by oligonucleotide microarray analysis

<p>Abstract</p> <p>Background</p> <p>The present study is aimed at identifying potential candidate genes as prognostic markers in human oral tongue squamous cell carcinoma (SCC) by large scale gene expression profiling.</p> <p>Methods</p> <p>The gene expression profile of patients (n=37) with oral tongue SCC were analyzed using Affymetrix HG_U95Av2 high-density oligonucleotide arrays. Patients (n=20) from which there were available tumor and matched normal mucosa were grouped into stage (early vs. late) and nodal disease (node positive vs. node negative) subgroups and genes differentially expressed in tumor vs. normal and between the subgroups were identified. Three genes, <it>GLUT3</it>, <it>HSAL2</it>, and <it>PACE4</it>, were selected for their potential biological significance in a larger cohort of 49 patients via quantitative real-time RT-PCR.</p> <p>Results</p> <p>Hierarchical clustering analyses failed to show significant segregation of patients. In patients (n=20) with available tumor and matched normal mucosa, 77 genes were found to be differentially expressed (P< 0.05) in the tongue tumor samples compared to their matched normal controls. Among the 45 over-expressed genes, <it>MMP-1</it> encoding interstitial collagenase showed the highest level of increase (average: 34.18 folds). Using the criterion of two-fold or greater as overexpression, 30.6%, 24.5% and 26.5% of patients showed high levels of <it>GLUT3</it>, <it>HSAL2</it> and <it>PACE4</it>, respectively. Univariate analyses demonstrated that <it>GLUT3</it> over-expression correlated with depth of invasion (P<0.0001), tumor size (P=0.024), pathological stage (P=0.009) and recurrence (P=0.038). <it>HSAL2</it> was positively associated with depth of invasion (P=0.015) and advanced T stage (P=0.047). In survival studies, only <it>GLUT3</it> showed a prognostic value with disease-free (P=0.049), relapse-free (P=0.002) and overall survival (P=0.003). <it>PACE4</it> mRNA expression failed to show correlation with any of the relevant parameters. </p> <p>Conclusion</p> <p>The characterization of genes identified to be significant predictors of prognosis by oligonucleotide microarray and further validation by real-time RT-PCR offers a powerful strategy for identification of novel targets for prognostication and treatment of oral tongue carcinoma.</p

Management of Hazardous Waste and Contaminated Land

Regulation of hazardous waste and cleanup of contaminated sites are two major components of modern public policy for environmental protection. We review the literature on these related areas, with emphasis on empirical analyses. Researchers have identified many behavioral responses to regulation of hazardous waste, including changes in the location of economic activity. However, the drivers behind compliance with these costly regulations remain a puzzle, as most research suggests a limited role for conventional enforcement. Increasingly sophisticated research examines the benefits of cleanup of contaminated sites, yet controversy remains about whether the benefits of cleanup in the U.S. exceed its costs. Finally, research focusing on the imposition of legal liability for damages from hazardous waste finds advantages and disadvantages of the U.S. reliance on legal liability to pay for cleanup, as opposed to the government-financed approaches more common in Europe

Genetic approaches to human renal agenesis/hypoplasia and dysplasia

Congenital abnormalities of the kidney and urinary tract are frequently observed in children and represent a significant cause of morbidity and mortality. These conditions are phenotypically variable, often affecting several segments of the urinary tract simultaneously, making clinical classification and diagnosis difficult. Renal agenesis/hypoplasia and dysplasia account for a significant portion of these anomalies, and a genetic contribution to its cause is being increasingly recognized. Nevertheless, overlap between diseases and challenges in clinical diagnosis complicate studies attempting to discover new genes underlying this anomaly. Most of the insights in kidney development derive from studies in mouse models or from rare, syndromic forms of human developmental disorders of the kidney and urinary tract. The genes implicated have been shown to regulate the reciprocal induction between the ureteric bud and the metanephric mesenchyme. Strategies to find genes causing renal agenesis/hypoplasia and dysplasia vary depending on the characteristics of the study population available. The approaches range from candidate gene association or resequencing studies to traditional linkage studies, using outbred pedigrees or genetic isolates, to search for structural variation in the genome. Each of these strategies has advantages and pitfalls and some have led to significant discoveries in human disease. However, renal agenesis/hypoplasia and dysplasia still represents a challenge, both for the clinicians who attempt a precise diagnosis and for the geneticist who tries to unravel the genetic basis, and a better classification requires molecular definition to be retrospectively improved. The goal appears to be feasible with the large multicentric collaborative groups that share the same objectives and resources

Interferometric baseline performance estimations for multistatic synthetic aperture radar configurations derived from GRACE GPS observations

Recent studies have demonstrated the usefulness of global positioning system (GPS) receivers for relative positioning of formation-flying satellites using dual-frequency carrier-phase observations. The accurate determination of distances or baselines between satellites flying in formation can provide significant benefits to a wide area of geodetic studies. For spaceborne radar interferometry in particular, such measurements will improve the accuracy of interferometric products such as digital elevation models (DEM) or surface deformation maps. The aim of this study is to analyze the impact of relative position errors on the interferometric baseline performance of multistatic synthetic aperture radar (SAR) satellites flying in such a formation. Based on accuracy results obtained from differential GPS (DGPS) observations between the twin gravity recovery and climate experiment (GRACE) satellites, baseline uncertainties are derived for three interferometric scenarios of a dedicated SAR mission. For cross-track interferometry in a bistatic operational mode, a mean 2D baseline error (1σ) of 1.4mm is derived, whereas baseline estimates necessary for a monostatic acquisition mode with a 50 km along-track separation reveal a 2D uncertainty of approximately 1.7mm. Absolute orbit solutions based on reduced dynamic orbit determination techniques using GRACE GPS code and carrier-phase data allows a repeat-pass baseline estimation with an accuracy down to 4 cm (2D 1σ). To assess the accuracy with respect to quality requirements of high-resolution DEMs, topographic height errors are derived from the estimated baseline uncertainties. Taking the monostatic pursuit flight configuration as the worst case for baseline performance, the analysis reveals that the induced low-frequency modulation (height bias) fulfills the relative vertical accuracy requirement (σ smaller than 1 m linear point-to-point error) according to the digital terrain elevation data level 3 (DTED-3) specifications for most of the baseline constellations. The use of a GPS-based reduced dynamic orbit determination technique improves the baseline performance for repeat-pass interferometry. The problem of fulfilling the DTED-3 horizontal accuracy requirements is still an issue to be investigated. DGPS can be used as an operational navigation tool for high-precision baseline estimation if a geodetic-grade dual-frequency spaceborne GPS receiver is assumed to be the primary instrument onboard the SAR satellites. The possibility of using only single-frequency receivers, however, requires further research effort

Operational Engineering of the COLUMBUS Thermal and Environmental Control System: Achievements, Optimizations

After commissioning of the European space-borne science laboratory Columbus, many operational products had to be improved and adapted to changing environmental conditions and new operational experiences. In this paper, we focus on the operational engineering of the Thermal Control as well as on the Environmental Control and Live Support System which are mainly influenced by crew activities, payloads and systems. We present an anomaly handling process how to overcome unexpected anomalies or system change requests. We apply this approach to two dedicated examples for which operational workarounds, a final recovery procedure and even a new operations concept had to be developed: (1) The introduction of a so-called Low Condensing Mode for the condensate heat exchanger due to changing station wide requirements and (2) impacts of unexpected smoke detector contamination. With the help of telemetry data, we explain workaround, final solution and operations concept development. We conclude how to change the Columbus air-conditioning and thermal control design to improve humidity control, condensate collection and smoke detector performance and give recommendations for the air-conditioning and smoke detector design of future human space flight missions

Applying differential InSAR to orbital dynamics: a new approach for estimating ERS trajectories

A new approach for tuning the trajectories of the European remote sensing (ERS) satellites is developed and assessed. Differential dual-pass interferometry is applied to calculate interferograms from the phase difference of synthetic aperture radar (SAR) images acquired by the ERS satellites over the site of the 1992 earthquake in Landers, California. These interferograms contain information about orbital trajectories and geophysical deformation. Beginning with good prior estimates of the orbital trajectories, a radial and an across-track orbital adjustment is estimated at each epoch. The data are the fringe counts along distance and azimuth. Errors in the across-track and radial components of the orbit estimates produce fringes in the interferograms. The spacing between roughly parallel fringes gives the gradients in distance and azimuth coordinates. The approach eliminates these fringes from interferometric pairs spanning relatively short time intervals containing few topographic residuals or atmospheric artefacts. An optimum interferometric path with six SAR acquisitions is selected to study post- and inter-seismic deformation fields. In order to regularize the problem, it is assumed that the radial and across-track adjustments both sum to zero. Applying the adjustment approach to the prior estimates of trajectory from the Delft Institute for Earth-Orientated Space Research (DEOS), root mean squares of 7.3 cm for the acrosstrack correction components and 2.4 cm for the radial ones are found. Assuming 0.1 fringes for the a priori standard deviation of the measurement, the approach yields mean standard deviations of 2.4 cm for the across-track and 4.5 cm for the radial components. The approach allows an &quot;interval by interval&quot; improvement of a set of orbital estimates from which post-fit interferograms of different time intervals spanning a total 3.8-year inter-seismic time interval can be created. The interferograms calculated with the post-fit orbital estimates compare favorably with those corrected with a conventional orbital tuning approach. Using the adjustment approach, it is possible to distinguish between orbital and deformation contributions to interferometric SAR (InSAR) phase gradients. Surface deformation changes over an inter-seismic time interval longer than one year can be measured. This approach is, however, limited to well-correlated interferograms where it is possible to measure the fringe gradient