486 research outputs found

    Special coatings control temperature of structures

    Get PDF
    Special coatings in the form of paints that exhibit controlled ratios of sunlight absorptivity to grey-body emissivity control the temperature of structures in space flight. These finishes exhibit good resistance to ultraviolet radiation and do not discolor

    Two & A Half Parents: Three-Parent IVF and Medical Malpractice in the United States

    Get PDF
    Fertility medicine is seeing a rapid advancement with the emergence of a new procedure called three-parent in vitro fertilization (IVF). This novel procedure provides an opportunity for women who have defective mitochondria to bear their own healthy genetic children. As women encounter fertility issues, they will often turn to regular IVF by receiving an egg from a donor—ultimately resulting in a child with no genetic relation to the mother. Women with defective mitochondria will likely pass down a mitochondrial disease to their children, therefore, bearing a child without the assistance from a donor does not present a viable option. Mitochondrial disease can be quite severe and traumatic, usually affecting the central nervous system. It can contribute to many serious illnesses such as Parkinson’s, Alzheimer’s, and cancer. Currently, there are no treatment options available for people with mitochondrial disease. Regular IVF requires an egg from a donor to replace the mothers egg, therefore, the mother is not genetically related to the child she bears, as the egg donor is the genetic mother. Three-parent IVF is a breakthrough fertility treatment procedure that allows women with defective mitochondria to bear a healthy child by receiving healthy mitochondria from a donor. This procedure enables women to retain a genetic bond to their child. Since a donor’s healthy mitochondria is transferred to the mother’s egg, the child will technically have three genetic parents (two mothers and a father). Three-parent IVF is currently not allowed in the United States, but with responsible legislation, it could be legal in the near future. This Comment proposes that three-parent IVF is implemented as a clinical trial for the purposes of conducting research to assess for safety and effectiveness. Current safety regulations and guidelines, primarily those regarding human tissue donation and transplantation, are quite instructive when put in the three-parent IVF context. These regulations and guidelines are discussed in some detail. There are a couple of steps that need to be taken in order to successfully implement three-parent IVF in the United States. First, great strides need to be made to reform the broken medical malpractice system in the United States. Current medical malpractice standards, and the available remedies to fertility plaintiffs, are not adequate to accommodate such a procedure. This Comment proposes that we move away from the customary care standard, and towards an evidence-based standard of care, while adopting the reasonable patient standard of informed consent. These standards will help address the inefficiency problems that exist within the medical profession. Second, since medical malpractice lawsuits are too costly for most fertility plaintiffs to pursue, there needs to be a fertility court established within the United States Court of Federal Claims—following in the successful footsteps of vaccine court. A fertility court will give fertility plaintiffs a remedy when they are injured by a doctor’s negligence, when no such remedy would have otherwise been available. Also, the establishment of a fertility court will lower fertility doctor’s medical malpractice premiums by reducing their overall litigation liability—as fertility plaintiffs will primarily turn to fertility court to redress their injuries. The United Kingdom is leading the world into the future by being the first country to approve the three-parent IVF procedure. The time has come for the United States to take a serious look at three-parent IVF to help advance fertility medicine into a promising and hopeful future

    Combining Models of Approximation with Partial Learning

    Full text link
    In Gold's framework of inductive inference, the model of partial learning requires the learner to output exactly one correct index for the target object and only the target object infinitely often. Since infinitely many of the learner's hypotheses may be incorrect, it is not obvious whether a partial learner can be modifed to "approximate" the target object. Fulk and Jain (Approximate inference and scientific method. Information and Computation 114(2):179--191, 1994) introduced a model of approximate learning of recursive functions. The present work extends their research and solves an open problem of Fulk and Jain by showing that there is a learner which approximates and partially identifies every recursive function by outputting a sequence of hypotheses which, in addition, are also almost all finite variants of the target function. The subsequent study is dedicated to the question how these findings generalise to the learning of r.e. languages from positive data. Here three variants of approximate learning will be introduced and investigated with respect to the question whether they can be combined with partial learning. Following the line of Fulk and Jain's research, further investigations provide conditions under which partial language learners can eventually output only finite variants of the target language. The combinabilities of other partial learning criteria will also be briefly studied.Comment: 28 page

    Oscillator Strengths for B-X, C-X, and E-X Transitions in Carbon Monoxide

    Get PDF
    Band oscillator strengths for electronic transitions in CO were obtained at the Synchrotron Radiation Center of the University of Wisconsin-Madison. Our focus was on transitions that are observed in interstellar spectra with the Far Ultraviolet Spectroscopic Explorer; these transitions are also important in studies of selective isotope photodissociation where fractionation among isotopomers can occur. Absorption from the ground state (X ^1Sigma^+ v'' = 0) to A ^1Pi (v'= 5), B ^1Sigma^+ (v' = 0, 1), C ^1Sigma^+ (v' = 0, 1), and E ^1Pi (v' = 0) was measured. Fits to the A - X (5, 0) band, whose oscillator strength is well known, yielded the necessary column density and excitation temperature. These parameters were used in a least-squares fit of the observed profiles for the transitions of interest to extract their band oscillator strengths. Our oscillator strengths are in excellent agreement with results from recent experiments using a variety of techniques. This agreement provides the basis for a self-consistent set of f-values at far ultraviolet wavelengths for studies of interstellar (and stellar) CO.Comment: 22 pages, 3 figures, ApJS (in press

    A Map of Update Constraints in Inductive Inference

    Full text link
    We investigate how different learning restrictions reduce learning power and how the different restrictions relate to one another. We give a complete map for nine different restrictions both for the cases of complete information learning and set-driven learning. This completes the picture for these well-studied \emph{delayable} learning restrictions. A further insight is gained by different characterizations of \emph{conservative} learning in terms of variants of \emph{cautious} learning. Our analyses greatly benefit from general theorems we give, for example showing that learners with exclusively delayable restrictions can always be assumed total.Comment: fixed a mistake in Theorem 21, result is the sam

    An examination of the effects of self-regulatory focus on the perception of the media richness: the case of email

    Get PDF
    Communication is a key element in organizations’ business success. The media richness theory and the channel expansion theory are two of the most influential theories regarding the selection and use of communication media in organizations; however, literature has focused little on the effects of self-regulation by managers and employees in these theories. To analyze these topics, this study develops an empirical investigation by gathering data from 600 managers and employees using a questionnaire. The results suggest that the perception of media richness is positively affected when the individual shows a promotion focus or strategy.Peer ReviewedPostprint (author’s final draft

    Information and Communication Technology (ICT) and International Business Travel: Mobility Allies?

    Get PDF
    Like forecasts about the paperless office, technological solutions to the problem of international business travel continue to be deferred. As with the increased use of office paper, international business travel is defying predictions of its decline. There is growing evidence to suggest that business sectors which seem ideally placed to substitute information and communication technology (ICT) for travel, are actually generating more physical travel than other sectors. This paper develops a case study of the Irish software industry to exemplify why international travel is not diminishing in importance how and the ICT and business travel relationship is changing in this sector. The paper presents research findings that suggest that a cycle of substitution, generation and modification relationships have occurred as mobility interdependencies have developed.Peer Reviewe

    Reliability and validity of two fitness tracker devices in the laboratory and home environment for older community-dwelling people

    Get PDF
    © 2018 The Author(s). Background: Two-thirds of older Australians are sedentary. Fitness trackers have been popular with younger people and may encourage older adults to become more active. Older adults may have different gait patterns and as such it is important to establish whether fitness trackers are valid and reliable for this population. The aim of the study was to test the reliability and validity of two fitness trackers (Fitbit Flex and ChargeHR) by step count when worn by older adults. Reliability and validity were tested in two conditions: 1) in the laboratory using a two-minute-walk-test (2MWT) and 2) in a free-living environment. Methods: Two 2MWTs were completed while wearing the fitness trackers. Participants were videoed during each test. Participants were then given one fitness tracker and a GENEactiv accelerometer to wear at home for 14-days. Results: Thirty-one participants completed two 2MWTs and 30 completed the free-living procedure. Intra Class Correlation's of the fitness trackers with direct observation of steps (criterion validity) was high (ICC:0.86,95%CI:0.76,0.93). However, both fitness trackers underestimated steps. Excellent test-retest reliability (ICC = 0.75) was found between the two 2MWTs for each device, particularly the ChargeHR devices. Good strength of agreement was found for total distance and steps (fitness tracker) and moderate-to-vigorous physical activity (GENEactiv) for the free-living environment (Spearman Rho's 0.78 and 0.74 respectively). Conclusion: Reliability and validity of the Flex and ChargeHR when worn by older adults is good, however both devices underestimated step count within the laboratory environment. These fitness trackers appear suitable for consumer use and promoting physical activity for older adults

    Global health education: a pilot in trans-disciplinary, digital instruction

    Get PDF
    Background: The development of new global health academic programs provides unique opportunities to create innovative educational approaches within and across universities. Recent evidence suggests that digital media technologies may provide feasible and cost-effective alternatives to traditional classroom instruction; yet, many emerging global health academic programs lag behind in the utilization of modern technologies. Objective: We created an inter-departmental University of Southern California (USC) collaboration to develop and implement a course focused on digital media and global health. Design: Course curriculum was based on core tenants of modern education: multi-disciplinary, technologically advanced, learner-centered, and professional application of knowledge. Student and university evaluations were reviewed to qualitatively assess course satisfaction and educational outcomes. Results: ‘New Media for Global Health’ ran for 18 weeks in the Spring 2012 semester with N=41 students (56.1% global health and 43.9% digital studies students). The course resulted in a number of high quality global health-related digital media products available at http://iml420.wordpress.com/. Challenges confronted at USC included administrative challenges related to co-teaching and frustration from students conditioned to a rigid system of teacher-led learning within a specific discipline. Quantitative and qualitative course evaluations reflected positive feedback for the course instructors and mixed reviews for the organization of the course. Conclusion: The development of innovative educational programs in global health requires on-going experimentation and information sharing across departments and universities. Digital media technologies may have implications for future efforts to improve global health education
    • …
    corecore