2,901 research outputs found

    The Superposition Principle of Waves Not Fulfilled under M. W. Evans' O(3) Hypothesis

    Get PDF
    In 1992 M.W. Evans proposed a so-called O(3) symmetry of electromagnetic fields by adding a constant longitudinal "ghost field" to the well-known transversal plane em waves. He considered this symmetry as a new law of electromagnetics. Later on, since 2002, this O(3) symmetry became the center of his Generally Covariant Unified Field Theory which he recently renamed as ECE Theory. One of the best-checked laws of electrodynamics is the principle of linear superposition of electromagnetic waves, manifesting itself in interference phenomena. Its mathematical equivalent is the representation of electric and magnetic fields as vectors. By considering the superposition of two phase-shifted waves we show that the superposition principle is incompatible with M.W. Evans' O(3) hypothesis.Comment: 5 pages, no figure

    Consumer concerns: motivating to action.

    Get PDF
    Microbiologic safety is consumers' most frequently volunteered food safety concern. An increase in the level of concern in recent years suggests that consumers are more receptive to educational information. However, changing lifestyles have lessened the awareness of foodborne illness, especially among younger consumers. Failure to fully recognize the symptoms or sources of foodborne disease prevents consumers from taking corrective action. Consumer education messages should include the ubiquity of microorganisms, a comprehensive description of foodborne illnesses, and prevention strategies. Product labels should contain food-handling information and warnings for special populations, and foods processed by newer safety-enhancing technologies should be more widely available. Knowledge of the consequences of unsafe practices can enhance motivation and adherence to safety guidelines. When consumers mishandle food during preparation, the health community, food industry, regulators, and the media are ultimately responsible. Whether inappropriate temperature control, poor hygiene, or another factor, the error occurs because consumers have not been informed about how to handle food and protect themselves. The food safety message has not been delivered effectively

    Claw-free t-perfect graphs can be recognised in polynomial time

    Full text link
    A graph is called t-perfect if its stable set polytope is defined by non-negativity, edge and odd-cycle inequalities. We show that it can be decided in polynomial time whether a given claw-free graph is t-perfect

    Challenges to estimating vaccine impact using hospitalization data.

    Get PDF
    Because the real-world impact of new vaccines cannot be known before they are implemented in national programs, post-implementation studies at the population level are critical. Studies based on analysis of hospitalization rates of vaccine-preventable outcomes are typically used for this purpose. However, estimates of vaccine impact based on hospitalization data are particularly prone to confounding, as hospitalization rates are tightly linked to changes in the quality, access and use of the healthcare system, which often occur simultaneously with introduction of new vaccines. Here we illustrate how changes in healthcare delivery coincident with vaccine introduction can influence estimates of vaccine impact, using as an example reductions in infant pneumonia hospitalizations after introduction of the 10-valent pneumococcal conjugate vaccine (PCV10) in Brazil. To this end, we explore the effect of changes in several metrics of quality and access to public healthcare on trends in hospitalization rates before (2008-09) and after (2011-12) PCV10 introduction in 2010. Changes in infant pneumonia hospitalization rates following vaccine introduction were significantly associated with concomitant changes in hospital capacity and the fraction of the population using public hospitals. Importantly, reduction of pneumonia hospitalization rates after PCV10 were also associated with the expansion of outpatient services in several Brazilian states, falling more sharply where primary care coverage and the number of health units offering basic and emergency care increased more. We show that adjustments for unrelated (non-vaccine) trends commonly employed by impact studies, such as use of single control outcomes, are not always sufficient for accurate impact assessment. We discuss several ways to identify and overcome such biases, including sensitivity analyses using different denominators to calculate hospitalizations rates and methods that track changes in the outpatient setting. Employing these practices can improve the accuracy of vaccine impact estimates, particularly in evolving healthcare settings typical of low- and middle-income countries

    Mass Fatality Incidents and the Role of the Dental Hygienist: Are We Prepared?

    Get PDF
    Dental hygienists can fill critical roles during mass fatality incidents in the area of disaster victim identification, providing much needed support to forensic odontologists. The purpose of this paper is to bring awareness that research is needed to assess current dental hygiene programs, continuing education opportunities and the type of approach being used to develop and implement pedagogy in the forensic specialty area, specifically mass fatality preparedness and response for the dental hygienist. Because of the threat of terrorism in the U.S. and natural disasters like hurricanes, the need to prepare dental professionals in disaster response and fatality management is real. The authors\u27 recommendations are to incorporate training in the areas of risk management and infection control in the mortuary setting, antemortem and postmortem records comparison, safe usage of portable radiographic equipment, and proper radiographic technique for the deceased victim. Disaster victim identification training in these areas is necessary for the accurate, efficient and dignified identification of disaster victims while minimizing errors and increasing responder safety. The dental hygiene professional can assist disaster mortuary response efforts in a way that leverages multidisciplinary teams, if effective training programs are implemented

    Interventions for the Reduction of Dental Anxiety and Corresponding Behavioral Deficits in Children with Autism Spectrum Disorder

    Get PDF
    Autism Spectrum Disorder (ASD) can greatly inhibit a child\u27s communication and social interaction skills, impacting their comfort during dental hygiene treatment and services. Children with ASD may exhibit sensory sensitivities, fear of the unfamiliar and lack of socio-cognitive understanding, leading to anxiety and corresponding behavioral deficits. Since the prevalence rates for ASD have risen significantly in the past decade, increased emphasis has been placed on educational and behavior guidance techniques, which can be helpful for children with ASD because of their increased capabilities in visual-processing. The purpose of this literature review is to summarize the interventions available to reduce dental anxiety in children with ASD, and to determine which strategies are best suited for implementation by the dental hygienist. Advancements in technology and socio-behavioral interventions were assessed for appropriate use, efficacy and engagement in the target population. Interventions were categorized into the following groups: picture cards, video technologies and mobile applications

    Assessment of Mass Fatality Preparedness and Response Content in Dental Hygiene Education

    Get PDF
    When mass fatality incidents (MFIs) occur, they can quickly overwhelm local, state, and government agencies, resources, and personnel. It is important to have a rapid and effective response with skilled, multidisciplinary victim identification teams since specific skill sets are necessary to participate in mass fatality preparedness and response. The aims of this study were to determine the extent of formal education related to mass fatality preparedness and response training in U.S. dental hygiene programs and to assess program directors\u27 perceptions of the need for such training. A 23-item cross-sectional survey was emailed to 319 U.S. dental hygiene programs in 2015. Survey questions addressed if the program offered mass fatality preparedness and response training to its students and how much training was given, as well as collecting respondents\u27 demographics and opinions regarding education and training. An overall response rate of 36% was obtained, with 111 program chairs completing the survey. The results showed that only a small percentage of responding programs incorporated coursework related to mass fatality and preparedness in their curricula. Of the responding programs, 84% had no formal instruction on the role of a dental hygienist in MFIs; however, 53 of 69 program directors agreed or strongly agreed that the role of dental hygienists in MFIs should be covered in dental hygiene curricula. The top three barriers to incorporating such training reported by respondents were time requirements, lack of faculty expertise, and lack of equipment. Future research is needed to establish standardized competencies for mass fatality preparedness and response in dental hygiene education

    MRI of "diffusion" in the human brain: New results using a modified CE-FAST sequence.

    No full text
    “Diffusion-weighted” MRI in the normal human brain and in a patient with a cerebral metastasis is demonstrated. The method employed was a modified CE-FAST sequence with imaging times of only 6-10 s using a conventional 1.5-T whole-body MRI system (Siemens Magnetom). As with previous phantom and animal studies, the use of strong gradients together with macroscopic motions in vivo causes unavoidable artifacts in diffusion-weighted images of the human brain. While these artifacts are shown to be considerably reduced by averaging of 8-16 images, the resulting diffusion contrast is compromised by unknown signal losses due to motion
    • …
    corecore