419 research outputs found

    Community rotorcraft air transportation benefits and opportunities

    Get PDF
    Information about rotorcraft that will assist community planners in assessing and planning for the use of rotorcraft transportation in their communities is provided. Information useful to helicopter researchers, manufacturers, and operators concerning helicopter opportunities and benefits is also given. Three primary topics are discussed: the current status and future projections of rotorcraft technology, and the comparison of that technology with other transportation vehicles; the community benefits of promising rotorcraft transportation opportunities; and the integration and interfacing considerations between rotorcraft and other transportation vehicles. Helicopter applications in a number of business and public service fields are examined in various geographical settings

    Rubella metapopulation dynamics and importance of spatial coupling to the risk of congenital rubella syndrome in Peru

    Get PDF
    Rubella is generally a mild childhood disease, but infection during early pregnancy may cause spontaneous abortion or congenital rubella syndrome (CRS), which may entail a variety of birth defects. Consequently, understanding the age-structured dynamics of this infection has considerable public health value. Vaccination short of the threshold for local elimination of transmission will increase the average age of infection. Accordingly, the classic concern for this infection is the potential for vaccination to increase incidence in individuals of childbearing age. A neglected aspect of rubella dynamics is how age incidence patterns may be moulded by the spatial dynamics inherent to epidemic metapopulations. Here, we use a uniquely detailed dataset from Peru to explore the implications of this for the burden of CRS. Our results show that the risk of CRS may be particularly severe in small remote regions, a prediction at odds with expectations in the endemic situation, and with implications for the outcome of vaccination. This outcome results directly from the metapopulation context: specifically, extinction–re-colonization dynamics are crucial because they allow for significant leakage of susceptible individuals into the older age classes during inter-epidemic periods with the potential to increase CRS risk by as much as fivefold

    Affirming Basic Psychological Needs Promotes Mental Well-Being During the COVID-19 Outbreak

    Get PDF
    We tested if challenges to basic psychological needs (BPN) for autonomy, competence, and relatedness during the COVID-19 pandemic undermine people’s mental well-being. Furthermore, we tested if an intervention, affirmation of these psychological needs, enhances mental well-being. Results of Study 1 ( N = 153) showed that higher levels of satisfaction of BPN were related to higher well-being during the COVID-19 outbreak. In Study 2 ( N = 215), we employed an online intervention enhancing these BPN. We found increased mental well-being through bolstered relatedness in particular. The intervention also decreased perceived stress. Both studies showed that mental well-being during the COVID-19 pandemic is positively related to the ability to work as usual and the number of people contacted via phone or internet but not in person

    Synchrotron radiation from a charge moving along a helical orbit inside a dielectric cylinder

    Full text link
    The radiation emitted by a charged particle moving along a helical orbit inside a dielectric cylinder immersed into a homogeneous medium is investigated. Expressions are derived for the electromagnetic potentials, electric and magnetic fields, and for the spectral-angular distribution of radiation in the exterior medium. It is shown that under the Cherenkov condition for dielectric permittivity of the cylinder and the velocity of the particle image on the cylinder surface, strong narrow peaks are present in the angular distribution for the number of radiated quanta. At these peaks the radiated energy exceeds the corresponding quantity for a homogeneous medium by some orders of magnitude. The results of numerical calculations for the angular distribution of radiated quanta are presented and they are compared with the corresponding quantities for radiation in a homogeneous medium. The special case of relativistic charged particle motion along the direction of the cylinder axis with non-relativistic transverse velocity (helical undulator) is considered in detail. Various regimes for the undulator parameter are discussed. It is shown that the presence of the cylinder can increase essentially the radiation intensity.Comment: 18 pages, 8 EPS figure

    Quantum deformation of the angular distributions of synchrotron radiation. Emission of particles in the first excited state

    Full text link
    The exact expressions for the characteristics of synchrotron radiation of charged particles in the first excited state are obtained in analytical form using quantum theory methods. We performed a detailed analysis of the angular distribution structure of radiation power and its polarization for particles with spin 0 and 1/2. It is shown that the exact quantum calculations lead to results that differ substantially from the predictions of classical theory

    Inherited coding variants at the CDKN2A locus influence susceptibility to acute lymphoblastic leukaemia in children

    Get PDF
    There is increasing evidence from genome-wide association studies for a strong inherited genetic basis of susceptibility to acute lymphoblastic leukaemia (ALL) in children, yet the effects of protein-coding variants on ALL risk have not been systematically evaluated. Here we show a missense variant in CDKN2A associated with the development of ALL at genome-wide significance (rs3731249, P=9.4 × 10(-23), odds ratio=2.23). Functional studies indicate that this hypomorphic variant results in reduced tumour suppressor function of p16(INK4A), increases the susceptibility to leukaemic transformation of haematopoietic progenitor cells, and is preferentially retained in ALL tumour cells. Resequencing the CDKN2A-CDKN2B locus in 2,407 childhood ALL cases reveals 19 additional putative functional germline variants. These results provide direct functional evidence for the influence of inherited genetic variation on ALL risk, highlighting the important and complex roles of CDKN2A-CDKN2B tumour suppressors in leukaemogenesis.Heng Xu, Hui Zhang, Wenjian Yang, Rachita Yadav, Alanna C. Morrison, Maoxiang Qian, Meenakshi Devidas, Yu Liu, Virginia Perez-Andreu, Xujie Zhao, Julie M. Gastier-Foster, Philip J. Lupo, Geoff Neale, Elizabeth Raetz, Eric Larsen, W. Paul Bowman, William L. Carroll, Naomi Winick, Richard Williams, Torben Hansen, Jens-Christian Holm, Elaine Mardis, Robert Fulton, Ching-Hon Pui, Jinghui Zhang, Charles G. Mullighan, William E. Evans, Stephen P. Hunger, Ramneek Gupta, Kjeld Schmiegelow, Mignon L. Loh, Mary V. Relling, Jun J. Yan

    From the Yellow Springs to the Land of Immortality

    Full text link
    The Yellow Springs is a vivid metaphorical reference to the final destination of a mortal being and the dwelling place of a departed one in ancient China. In the writings of philosophers, historians, and poets during the long period of Chinese history, the Yellow Springs is not only considered as an underground physical locus where a grave is situated, but also an emotionally charged space invoke grieving, longing, and memory for the departed loved ones. The subterranean dwelling at the Yellow Springs is both a destination for a departed mortal being and an intermediary place to an ideal and imaginative realm, the land of immortality where the soul would enjoy eternity. From the Yellow Springs to the Land of Immortality is an exhibition that highlights sixteen carefully selected artworks from Gettysburg College’s Special Collections; each object embodies the perceptions and ritual practices of the rich funerary culture in the historical period in China, ranging from the late second millennium BCE to the beginning of the early twentieth century. These artifacts represent various artistic traditions and fabrication techniques — including jade carving, bronze casting, glazed pottery making — and most importantly, offer a glimpse of how art and artifacts are employed as a means to connect the living with the soul of the departed one in the Yellow Springs. Archaeo- logical discoveries in the past four decades in China have provided rich information that helps contextualize the sixteen artworks, as well as intimate knowledge about how the objects might “perform” in the life and afterlife of the individuals in the past. The practice of burying goods alongside departed loved ones has had a long tradition in China. The artworks included in this exhibition catalogue, encompassing the major dynasties in Chinese history, epitomize such a practice from a historical point of view. The bronze jue of the Shang dynasty (mid-16th c.-1046 BCE), and the miniature bell, a replica of yong bronze bell of the Zhou dynasty (1045-256 BCE), are not only ceremonial paraphernalia used by elites in ancestral sacrifices during the Bronze Age, but also material manifestations of ritual and music, the very foundations of ancient Chinese civilization. Comparable examples found in Bronze Age tombs illustrate the idea to connect the deceased, often the owner of these ritual objects, to the ancestors in the netherworld as they themselves were transitioned into the role of ancestors through a series of funerary ceremonies. [excerpt]https://cupola.gettysburg.edu/artcatalogs/1034/thumbnail.jp

    Sourcing illegal drugs as a hidden older user: the ideal of ‘social supply’

    Get PDF
    Aims: At a time of growing awareness regarding the non-commercial supply of illegal drugs between friends, this article explores the significance of so-called ‘social supply’ for a group of ‘hidden’ users of illegal drugs aged 40 and over. Methodology: Semi-structured interviews were conducted with 30 users of illegal drugs aged 40 and over who were not in contact with the criminal justice system or treatment agencies regarding their use. Participants were recruited using snowball sampling. Findings: Accessing drugs through the commercial market was considered as a less attractive proposition than social supply by the participants. The majority used only socially supplied drugs, with some engaging commercial dealers when socially supplied product was unavailable. A handful sourced drugs exclusively through the commercial market. Some were home growers of cannabis, and a small number had drifted into social supply themselves. Conclusions: Social supply was seen in a far more favourable light than commercial transactions by our participants, and acted as an ideal against which all other acts of sourcing were compared. Moreover, social supply was often an integral facet of the drug using experience and served to validate and enhance that experience. The relatively benign, non-predatory nature of the social supply engaged in by the participants lends support to calls for some reform of the offence of supply in UK law
    corecore