An Architecture for Coexistence with Multiple Users in Frequency Hopping Cognitive Radio Networks

The radio frequency (RF) spectrum is a limited resource. Spectrum allotment disputes stem from this scarcity as many radio devices are con confined to a fixed frequency or frequency sequence. One alternative is to incorporate cognition within a configurable radio platform, therefore enabling the radio to adapt to dynamic RF spectrum environments. In this way, the radio is able to actively observe the RF spectrum, orient itself to the current RF environment, decide on a mode of operation, and act accordingly, thereby sharing the spectrum and operating in more flexible manner. This research presents a novel framework for incorporating several techniques for the purpose of adapting radio operation to the current RF spectrum environment. Specifically, this research makes six contributions to the field of cognitive radio: (1) the framework for a new hybrid hardware/software middleware architecture, (2) a framework for testing and evaluating clustering algorithms in the context of cognitive radio networks, (3) a new RF spectrum map representation technique, (4) a new RF spectrum map merging technique, (5) a new method for generating a random key-based adaptive frequency-hopping waveform, and (6) initial integration testing toward implementing the proposed system on a field-programmable gate array (FPGA)

Networked sensing systems for detecting people carrying radioactive material

he goal of the research described in this paper is to help prevent scenarios such as the following: a terrorist detonates a device that distributes radioactive material such as Cesium-137 or Cobalt-60 in an open space used for public sports events or demonstrations. This paper studies the efficacy of networks of static sensors on street lamps or similar infrastructures. This paper describes individual sensors, evaluates the benefits of networks of stationary sensors, and briefly discusses the potential value of integrated networks of wireless-equipped mobile security personnel with stationary radiation sensors and cameras. The paper presents mathematical analysis coupled with simulation results

Fungi at the scene of the crime: innocent bystanders or accomplices in oral infections?

Purpose of Review: Over the last decade, microbiome studies have enhanced our knowledge and understanding of the polymicrobial nature of oral infections. Recently, profiling of the fungal microbiome has expanded our conventional understanding of oral ecology, revealing the critical importance of yeasts within this complex microbiome. This review aims to explore our current appreciation of interkingdom interactions in oral disease. Recent Findings: There is a growing evidence base of interactions and pathogenic synergy and antagonism with bacterial species within oral disease. Recent studies have helped to develop our knowledge of how Candida albicans, alongside bacteria such as Porphyromonas gingivalis, Streptococcus mutans, Staphylococcus aureus, Enterococcus faecalis, and Lactobacillus species, influence overall pathogenicity. Summary: Clinical and experimental evidence makes a compelling case for a role for C. albicans in a number of oral infections, though whether its role is an active accomplice or passive bystander remains to be determined

Designing for the Student: Users\u27 Styles and Department Web Sites

Researchers have recognized that students rely on different learning styles and strategies to succeed, and the importance of recognizing different learning styles is well documented (e.g., Cassidy 2004; Vermunt 1994; Bransford et al. 1989; Kolb 1985). The same is true of how students use technological resources; it has become increasingly clear that there is no one-size-fits-all solution for all students. While a great deal has been written on these topics, the literature addressing such differences has focused primarily on course content (Fahy and Ally 2005; Lee et al. 2005; Ross and Lukow 2004; Baldwin and Sabry 2003; Brown, Bull, and Pendlebury 1997). There remains a dearth of research about the ancillary aspects of the education experience and about the uses of technologies not directly related to content but which students nonetheless incorporate into their overall learning and communication strategies. In this vein, academic department Web pages are important resources for students in higher education. These sites provide students with contact information for faculty members, sometimes including direct links to faculty members\u27 home and course pages; information about class offerings and frequency; and data about the major, internships, external experiences, job placement, and the like. For some students, the department Web site becomes a support for academic advising and could be considered, in the broadest sense, a source for answers to frequently asked questions. Although academic department Web pages play an important role in communicating with students, little research has been done to determine what kinds of information current students value on department Web pages. In this study, we examine how students value information commonly placed on department Web pages and suggest that just as in learning, different users have different information needs

Undergraduate Health Care Ethics Internship: An Ignatian Innovation in Bioethics Education

This article describes an innovative and unique undergraduate bioethics course for students planning careers in health care. The Health Care Ethics Internship reflects the Ignatian values of (1) cura personalis signifying care for the whole person, both of the interns themselves and the patients and professionals they encounter and (2) being a person for others concerned not only with success but also with those poor in health and opportunity. Developed by Santa Clara University’s Markkula Center for Applied Ethics, the Health Care Ethics Internship is interdisciplinary, integrating experiential learning in various health care contexts with ethical theory and reflection with particular attention to justice. Surveys collected from participants indicate that the Internship: (1) influenced career decisions; (2) provided knowledge that was subsequently used in personal and professional ethical decision making; (3) enabled participants to more easily recognize ethical concerns and to think more critically about them; and, (4) prepared them to address ethical challenges encountered in post-graduate health care education

Calibration and alignment of metrology system for the Nuclear Spectroscopic Telescope Array mission

A metrology system to measure the on-orbit movement of a ten meter mast has been built for the Nuclear Spectroscopic Telescope Array (NuSTAR) x-ray observatory. In this paper, the metrology system is described, and the performance is measured. The laser beam stability is discussed in detail. Pre-launch alignment and calibration are also described. The invisible infrared laser beams must be aligned to their corresponding detectors without deploying the telescope in Earth’s gravity. Finally, a possible method for in-flight calibration of the metrology system is described

Gaining insights from Candida biofilm heterogeneity: one size does not fit all

Despite their clinical significance and substantial human health burden, fungal infections remain relatively under-appreciated. The widespread overuse of antibiotics and the increasing requirement for indwelling medical devices provides an opportunistic potential for the overgrowth and colonization of pathogenic Candida species on both biological and inert substrates. Indeed, it is now widely recognized that biofilms are a highly important part of their virulence repertoire. Candida albicans is regarded as the primary fungal biofilm forming species, yet there is also increasing interest and growing body of evidence for non-Candida albicans species (NCAS) biofilms, and interkingdom biofilm interactions. C. albicans biofilms are heterogeneous structures by definition, existing as three-dimensional populations of yeast, pseudo-hyphae, and hyphae, embedded within a self-produced extracellular matrix. Classical molecular approaches, driven by extensive studies of laboratory strains and mutants, have enhanced our knowledge and understanding of how these complex communities develop, thrive, and cause host-mediated damage. Yet our clinical observations tell a different story, with differential patient responses potentially due to inherent biological heterogeneity from specific clinical isolates associated with their infections. This review explores some of the recent advances made in an attempt to explore the importance of working with clinical isolates, and what this has taught us

Learning in the Geoscience Classroom: Q-Methodology, Learning Styles, and Individual Preferences

One of the challenges of traditional student learning, from an instructor\u27s perspective, involves achieving an understanding of how students learn. Q-method is an effective approach to improve understanding of human subjectivity, and, as this research suggests, it is an appropriate tool to assist educators to better understand how students learn. In particular, Q-methodology provides the educator with a robust tool to assess student learning styles. This paper adapted an existing learning style instrument to a Q-method analysis in an introductory geographic information system class. The analysis resulted in three learning groups: lone pragmatist, explorer, and synergistic. These three learning groups are described. The paper concludes that the use of Q-method can deepen understanding of students\u27 learning skills and improve instruction through more balanced and learner-focused curricular approaches

Soil Phase Photodegradation of Toxic Organics at Contaminated Disposal Sites for Soil Renovation and Groundwater Quality Protection

Accurate assessment of the potential for contaminated soil remediation requires detailed knowledge of the fate of waste constituents within the soil environment. For many non-biodegradable organics compounds, photochemical degradation may provide a potential pathway for the removal of such compounds from soil surfaces. A study was conducted to evaluate the rate of photodegradation of ten hazardous organic compounds from three soils, silica gel, and four soil minerals (kaolinite, montmorillonite, illite, and calcite) under conditions of controlled irradiation. In addition, the effect of siz amendment treatments (methylene blue, riboflavin, hydrogen peroxide, diethylamine, peat moss, and silica gel) on the rates of compound loss was also investigated. Soil and mineral samples were spiked with various combinations of m-cresol, quinoline, biphenyl, dibenzo[a]furan, fluorene, pentachlorophenol, phenanthrene, anthracene, 9H-carbazole and pyrene at either 500 or 1000 mg/kg initial soil concentration of each chemical. Amendments were applied to the soils and minerals and duplicate samples were irradiated in petri dishes under ultraviolet or visible light while spike controls were inclubated in the dark. Linear regression of soil/mineral contaminant concentration data showed that first order kinetic modeling best described the degradation process. Significant loss of anthracene occurred on all surfaces tested althrough the rate of loss varied with surface type and, for some surfaces, with the spiking solution concentration and chemical mixtures. Anthracene loss from silica gel was the msot rapid of all reactions observed. Skumpah soil, a light colored alkaline soil, yielded the greatest reduction in contaminant concentrations found in the soil studies. Calcium kaolinite displaed the most rapid kinetics of the mineral surfaces tested. Loss of the other test compounds was observed from only some of the surfaces investigated. Anthraquinone and fluorenone were identified as the major degradation products of the photoreaction of anthracene and fluorene. Under the conditions of this study, soild and mineral type, as well as surface renewal via mixing, were found to have more effect on degradation rates than any of the amendments that were tested