Specific-to-General Learning for Temporal Events with Application to Learning Event Definitions from Video

We develop, analyze, and evaluate a novel, supervised, specific-to-general learner for a simple temporal logic and use the resulting algorithm to learn visual event definitions from video sequences. First, we introduce a simple, propositional, temporal, event-description language called AMA that is sufficiently expressive to represent many events yet sufficiently restrictive to support learning. We then give algorithms, along with lower and upper complexity bounds, for the subsumption and generalization problems for AMA formulas. We present a positive-examples--only specific-to-general learning method based on these algorithms. We also present a polynomial-time--computable ``syntactic'' subsumption test that implies semantic subsumption without being equivalent to it. A generalization algorithm based on syntactic subsumption can be used in place of semantic generalization to improve the asymptotic complexity of the resulting learning algorithm. Finally, we apply this algorithm to the task of learning relational event definitions from video and show that it yields definitions that are competitive with hand-coded ones

Discrete time piecewise affine models of genetic regulatory networks

We introduce simple models of genetic regulatory networks and we proceed to the mathematical analysis of their dynamics. The models are discrete time dynamical systems generated by piecewise affine contracting mappings whose variables represent gene expression levels. When compared to other models of regulatory networks, these models have an additional parameter which is identified as quantifying interaction delays. In spite of their simplicity, their dynamics presents a rich variety of behaviours. This phenomenology is not limited to piecewise affine model but extends to smooth nonlinear discrete time models of regulatory networks. In a first step, our analysis concerns general properties of networks on arbitrary graphs (characterisation of the attractor, symbolic dynamics, Lyapunov stability, structural stability, symmetries, etc). In a second step, focus is made on simple circuits for which the attractor and its changes with parameters are described. In the negative circuit of 2 genes, a thorough study is presented which concern stable (quasi-)periodic oscillations governed by rotations on the unit circle -- with a rotation number depending continuously and monotonically on threshold parameters. These regular oscillations exist in negative circuits with arbitrary number of genes where they are most likely to be observed in genetic systems with non-negligible delay effects.Comment: 34 page

Evaluation of thermally stable phosphor screens for application in laser diode excited high brightness white light modules

A study on the preparation of thermally stable phosphor targets based on yttrium aluminum garnet doped with cerium (YAG:Ce) when excited by a high power laser diode is described. The luminous flux, chromaticity and radial spectral flux of the targets along with their thermal stability have been determined when exposed to laser powers of up to 5000 mW. This report presents successful high brightness light sources with adjustable emission properties achieved by utilizing thermally stable phosphor targets excited by high power laser diodes.Brunel University London, No. EP/K504208/

Infertility in Muslim Refugees: A Review of the Literature

Many couples worldwide are affected by infertility, which is defined as an inability to conceive after at least one year of regular unprotected sexual intercourse. Many Muslim and Middle Eastern societies place a high societal value on having children and therefore, couples who are unable to conceive for various reasons often find themselves feeling stigmatized and socially isolated. Muslim refugees living in the United States face additional challenges and barriers to care due to their refugee status. This review is a synthesis of existing literature that 1) identifies Islamic viewpoints on infertility and assistive reproductive technology (ART), 2) explores the psychosocial impact of infertility for Muslim refugees, and 3) identifies barriers to care for this population. A PubMed search was conducted which yielded 592 records. After screening and removal of duplicates, 37 full-length texts were included for review. Key findings included different religious perspectives regarding various forms of ART between the two major sects of Islam (Sunni and Shia), significant social stigma and stress from infertility, and barriers to care such as high cost of treatment. Future research is needed in this area to better provide culturally competent care to Muslim couples experiencing infertility

An Interoperability Concept for Detect and Avoid and Collision Avoidance Systems: Results from a Human-In-The-Loop Simulation

The integration of Unmanned Aircraft Systems (UAS) into the National Airspace System (NAS) poses a variety of technical challenges to UAS developers and aviation regulators. In response to growing demand for access to civil airspace in the United States, the Federal Aviation Administration (FAA) has produced a roadmap identifying key areas requiring further research and development. One such technical challenge is the development of a "detect and avoid" system (DAA) capable of providing a means of compliance with the "see and avoid" requirement in manned aviation. The purpose of the DAA system is to support the pilot, situated at a ground control station (GCS), in maintaining "DAA well clear" of nearby aircraft through the use of GCS displays and alerts. In addition to its primary function of aiding the pilot in maintaining DAA well clear, the DAA system must also safely interoperate with existing NAS systems and operations, such as the airspace management procedures of air traffic controllers (ATC) and Collision Avoidance (CA) systems currently in use by manned aircraft, namely the Traffic Alert and Collision Avoidance System (TCAS II). It is anticipated that many UAS architectures will integrate both a DAA system and a TCAS II. It is therefore necessary to explicitly study the integration of DAA and TCAS II alerting structures and maneuver guidance formats to ensure that pilots understand the appropriate type and urgency of their response to the various alerts. This paper presents a concept of interoperability for the two systems. The concept was developed with the goal of avoiding any negative impact on the performance level of TCAS II while retaining a DAA system that still effectively enables pilots to maintain DAA well clear. The interoperability concept described in the paper focuses primarily on facilitating the transition from a late-stage DAA encounter (where a loss of DAA well clear is imminent) to a TCAS II Corrective Resolution Advisory (RA), which requires pilot compliance within five seconds of its issuance. The interoperability concept was presented to 10 participants (6 active UAS pilots and 4 active commercial pilots) in a medium-fidelity, human-in-the-loop simulation designed to stress different aspects of the DAA and TCAS II systems. Pilots' ability to maintain separation, their rate of compliance and response times using the interoperability concept are reported. Results indicated that pilots exhibited comprehension of, and appropriate prioritization within, the DAA-TCAS II combined alert structure. Pilots demonstrated a high rate of compliance with TCAS II RAs and were also seen to respond to corrective RAs within the five second requirement established for manned aircraft. The DAA system presented under test was also shown to be effective in supporting pilots' ability to maintain DAA well clear in the overwhelming majority of cases in which pilots had sufficient time to respond

Geographic bias related to geocoding in epidemiologic studies

BACKGROUND: This article describes geographic bias in GIS analyses with unrepresentative data owing to missing geocodes, using as an example a spatial analysis of prostate cancer incidence among whites and African Americans in Virginia, 1990–1999. Statistical tests for clustering were performed and such clusters mapped. The patterns of missing census tract identifiers for the cases were examined by generalized linear regression models. RESULTS: The county of residency for all cases was known, and 26,338 (74%) of these cases were geocoded successfully to census tracts. Cluster maps showed patterns that appeared markedly different, depending upon whether one used all cases or those geocoded to the census tract. Multivariate regression analysis showed that, in the most rural counties (where the missing data were concentrated), the percent of a county's population over age 64 and with less than a high school education were both independently associated with a higher percent of missing geocodes. CONCLUSION: We found statistically significant pattern differences resulting from spatially non-random differences in geocoding completeness across Virginia. Appropriate interpretation of maps, therefore, requires an understanding of this phenomenon, which we call "cartographic confounding.

Virginia Refugee’s Access to COVID 19 Health Information

Background: This study examined how refugees in central Virginia, United States were able to access public health information about COVID-19 and any barriers to following COVID-19 prevention guidelines. Methods: Individual interviews were conducted with refugees (n = 40) attending a family medicine clinic serving refugees and immigrants. Participants answered questions about their primary methods of obtaining COVID-19 and COVID-19 vaccine information, how they prefer to receive this information, information given by employers, precautions taken at their place of work, and current vaccination status. Results: We found that television and social media played a large role for refugees in obtaining COVID-19 information. Participants noted they preferred in-person visits and phone calls to communicate with their healthcare providers, who were important for disseminating vaccine information. Discussion: This is one of the first studies to explore how refugees obtain health information related to COVID-19 and the vaccine, and provides valuable information as vaccination outreach continues in light of new viral strains and increased need for booster vaccinations. Conclusion: The results of this study can guide development of health communication materials to engage refugee communities as the COVID-19 pandemic evolves and responses to i

Surface plasmon resonance imaging detection of silver nanoparticle-tagged immunoglobulin

This article is available open access through the publisher’s website at the link below. Copyright @ 2011 The Royal Society.The detection sensitivity of silver nanoparticle (AgNP)-tagged goat immunoglobulin G (gIgG) microarrays was investigated by studying surface plasmon resonance (SPR) images captured in the visible wavelength range with the help of a Kretchmann-configured optical coupling set-up. The functionalization of anti-gIgG molecules on the AgNP surface was studied using transmission electron microscopy, photon correlation measurements and UV–visible absorption spectroscopy. A value of 1.3 × 107 M−1 was obtained for the antibody–antigen binding constant by monitoring the binding events at a particular resonance wavelength. The detection limit of this SPR imaging instrument is 6.66 nM of gIgG achieved through signal enhancement by a factor of larger than 4 owing to nanoparticle tagging with the antibody.The European Commissio