5,945 research outputs found

    Pulsed Doppler lidar airborne scanner

    Get PDF
    This report covers the work accomplished during the reporting period on Pulsed Doppler Lidar Airborne Scanner and describes plans for the next reporting period. The objectives during the current phase of the contract are divided into four phases. Phase 1 includes ground testing of the system and analysis of data from the 1981 Severe Storms Test Flights. Phase 2 consists of preflight preparation and planning for the 1983 flight series. The flight test itself will be performed during Phase 3, and Phase 4 consists of post-flight analysis and operation of the system after that flight test. The range profile from five samples taken during Flight 10, around 1700 Z is given. The lowest curve is taken from data collected upwind of Mt. Shasta at about 10,000 feet of altitude, in a clear atmosphere, where no signals were observed. It thus is a good representation of the noise level as a function of range. The next curve was taken downwind of the mountain, and shows evidence of atmospheric returns. There is some question as to whether the data are valid at all ranges, or some ranges are contaminated by the others

    Laws relating runs, long runs, and steps in gambler's ruin, with persistence in two strata

    Full text link
    Define a certain gambler's ruin process \mathbf{X}_{j}, \mbox{ \ }j\ge 0, such that the increments εj:=XjXj1\varepsilon_{j}:=\mathbf{X}_{j}-\mathbf{X}_{j-1} take values ±1\pm1 and satisfy P(εj+1=1εj=1,Xj=k)=P(εj+1=1εj=1,Xj=k)=akP(\varepsilon_{j+1}=1|\varepsilon_{j}=1, |\mathbf{X}_{j}|=k)=P(\varepsilon_{j+1}=-1|\varepsilon_{j}=-1,|\mathbf{X}_{j}|=k)=a_k, all j1j\ge 1, where ak=aa_k=a if 0kf1 0\le k\le f-1, and ak=ba_k=b if fk<Nf\le k<N. Here 0<a,b<10<a, b <1 denote persistence parameters and f,NN f ,N\in \mathbb{N} with f<Nf<N. The process starts at X0=m(N,N)\mathbf{X}_0=m\in (-N,N) and terminates when Xj=N|\mathbf{X}_j|=N. Denote by RN{\cal R}'_N, UN{\cal U}'_N, and LN{\cal L}'_N, respectively, the numbers of runs, long runs, and steps in the meander portion of the gambler's ruin process. Define XN:=(LN1ab(1a)(1b)RN1(1a)(1b)UN)/NX_N:=\left ({\cal L}'_N-\frac{1-a-b}{(1-a)(1-b)}{\cal R}'_N-\frac{1}{(1-a)(1-b)}{\cal U}'_N\right )/N and let fηNf\sim\eta N for some 0<η<10<\eta <1. We show limNE{eitXN}=φ^(t)\lim_{N\to\infty} E\{e^{itX_N}\}=\hat{\varphi}(t) exists in an explicit form. We obtain a companion theorem for the last visit portion of the gambler's ruin.Comment: Presented at 8th International Conference on Lattice Path Combinatorics, Cal Poly Pomona, Aug., 2015. The 2nd version has been streamlined, with references added, including reference to a companion document with details of calculations via Mathematica. The 3rd version has 2 new figures and improved presentatio

    Childhood tuberculosis infection and disease: A spatial and temporal transmission analysis in a South African township

    Get PDF
    Background. Tuberculosis (TB) remains a leading cause of mortality and morbidity in South Africa. While adult TB results from both recent and past infection, childhood TB results from recent infection and reflects ongoing transmission despite current TB control strategies.Setting. A South African community with high rates of TB and HIV disease.Outcomes. A Geographic Information System was used to spatially and temporally define the relationships between TB exposure, infection and disease in childre

    Identification of a novel retroviral gene unique to human immunodeficiency virus type 2 and simian immunodeficiency virus SIVMAC

    Get PDF
    Human and simian immunodeficiency-associated retroviruses are extraordinarily complex, containing at least five genes, tat, art, sor, R, and 3' orf, in addition to the structural genes gag, pol, and env. Recently, nucleotide sequence analysis of human immunodeficiency virus type 2 (HIV-2) and simian immunodeficiency virus SIVMAC revealed the existence of still another open reading frame, termed X, which is highly conserved between these two viruses but absent from HIV-1. In this report, we demonstrate for the first time that the X open reading frame represents a functional retroviral gene in both HIV-2 and SIVMAC and that it encodes a virion-associated protein of 14 and 12 kilodaltons, respectively. We also describe the production of recombinant TrpE/X fusion proteins in Escherichia coli and show that sera from some HIV-2-infected individuals specifically recognize these proteins

    Recruiting and consenting into a peripartum trial in an emergency setting: a qualitative study of the experiences and views of women and healthcare professionals.

    Get PDF
    BACKGROUND: Recruiting and consenting women to peripartum trials can be challenging as the women concerned may be anxious, in pain, and exhausted; there may also be limited time for discussion and decision-making to occur. To address these potential difficulties, we undertook a qualitative evaluation of the internal pilot of a trial (Got-it) involving women who had a retained placenta (RP). We explored the experiences and views of women and staff about the information and consent pathway used within the pilot, in order to provide recommendations for use in future peripartum trials involving recruitment in emergency situations. METHODS: In-depth interviews were undertaken with staff (n = 27) and participating women (n = 22). Interviews were analysed thematically. The accounts of women and staff were compared to identify differences and similarities in their views about recruitment and consent procedures. RESULTS: Women and staff regarded recruitment as having been straightforward and facilitated by the use of simplified (verbal and written) summaries of trial information. Both parties, however, conveyed discordant views about whether fully informed consent had been obtained. These differences in perspectives appeared to arise from the different factors and considerations impinging on women and staff at the time of recruitment. While staff placed emphasis on promoting understanding in the emergency situation of RP by imparting information in clear and succinct ways, women highlighted the experiential realities of their pre- and post-birthing situations, and how these had led to quick decisions being made without full engagement with the potential risks of trial participation. To facilitate informed consent, women suggested that trial information should be given during the antenatal period, and, in doing so, articulated a rights-based discourse. Staff, however, voiced opposition to this approach by emphasising a duty of care to all pregnant women, and raising concerns about causing undue distress to the majority of individuals who would not subsequently develop a RP. CONCLUSIONS: By drawing upon the perspectives of women and staff involved in the same trial we have shown that they may operate within different experiential and ethical paradigms. In doing so, we argue for the potential benefits of drawing upon multiple perspectives when developing information and consent pathways used in future (peripartum) trials. TRIAL REGISTRATION: ISCRTN 88609453

    Seed Storage Reserves and Glucosinolates in Brassica rapa L. Grown on the International Space Station

    Get PDF
    Although plants are envisioned to play a central role in life support systems for future long-duration space travel, plant growth in space has been problematic due to horticultural problems of nutrient delivery and gas resupply posed by the weightless environment. Iterative improvement in hardware designed for growth of plants on orbital platforms now provides confidence that plants can perform well in microgravity, enabling investigation of their nutritional characteristics. Plants of B. rapa (cv. Astroplants) were grown in the Biomass Production System on the International Space Station. Flowers were hand-pollinated and seeds were produced prior to harvest at 39 days after planting. The material was frozen or fixed while on orbit and subsequently analyzed in our laboratories. Gross measures of growth, leaf chlorophyll, starch and soluble carbohydrates confirmed comparable performance by the plants in spaceflight and ground control treatments. Analysis of glucosinolate production in the plant stems indicated that 3-butenylglucosinolate concentration was on average 75% greater in flight samples than in ground control samples. Similarly, the biochemical make-up of immature seeds produced during spaceflight and fixed or frozen while in orbit was significantly different from the ground controls. The immature seeds from the spaceflight treatment had higher concentrations of chlorophyll, starch, and soluble carbohydrates than the ground controls. Seed protein was significantly lower in the spaceflight material. Microscopy of immature seeds fixed in flight showed embryos to be at a range of developmental stages, while the ground control embryos had all reached the premature stage of development. Storage reserve deposition was more advanced in the ground control seeds. The spaceflight environment thus influences B. rapa metabolite production in ways that may affect flavor and nutritional quality of potential space produce

    Tbx1 and Brn4 regulate retinoic acid metabolic genes during cochlear morphogenesis

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>In vertebrates, the inner ear is comprised of the cochlea and vestibular system, which develop from the otic vesicle. This process is regulated via inductive interactions from surrounding tissues. <it>Tbx1</it>, the gene responsible for velo-cardio-facial syndrome/DiGeorge syndrome in humans, is required for ear development in mice. <it>Tbx1 </it>is expressed in the otic epithelium and adjacent periotic mesenchyme (POM), and both of these domains are required for inner ear formation. To study the function of <it>Tbx1 </it>in the POM, we have conditionally inactivated <it>Tbx1 </it>in the mesoderm while keeping expression in the otic vesicle intact.</p> <p>Results</p> <p>Conditional mutants (<it>TCre-KO</it>) displayed malformed inner ears, including a hypoplastic otic vesicle and a severely shortened cochlear duct, indicating that <it>Tbx1 </it>expression in the POM is necessary for proper inner ear formation. Expression of the mesenchyme marker <it>Brn4 </it>was also lost in the <it>TCre-KO</it>. <it>Brn4</it><sup>-</sup>;<it>Tbx1</it><sup>+/-</sup>embryos displayed defects in growth of the distal cochlea. To identify a potential signal from the POM to the otic epithelium, expression of retinoic acid (RA) catabolizing genes was examined in both mutants. <it>Cyp26a1 </it>expression was altered in the <it>TCre-KO</it>, while <it>Cyp26c1 </it>showed reduced expression in both <it>TCre-KO </it>and <it>Brn4</it><sup>-</sup>;<it>Tbx1</it><sup>+/- </sup>embryos.</p> <p>Conclusion</p> <p>These results indicate that <it>Tbx1 </it>expression in the POM regulates cochlear outgrowth potentially via control of local retinoic acid activity.</p

    Young children's cognitive achievement: home learning environment, language and ethnic background

    Get PDF
    For decades, research has shown differences in cognitive assessment scores between White and minority ethnic group(s) learners as well as differences across different minority ethnic groups. More recent data have indicated that the home learning environment and languages spoken can impact cognitive assessment and other corollary outcomes. This study uses the Millennium Cohort Study to jointly assess how minority ethnic group, home learning environment and home languages predict child cognitive assessment scores. Regression analyses were conducted using two assessment measures. The following is hypothesised: (1) cognitive achievement scores vary by minority ethnic group, (2) more home learning environment in early childhood leads to higher cognitive development scores and (3) English only in the home yields the highest cognitive scores while no English in the home yields the lowest. Findings reveal that there are differences in cognitive scores along ethnic group categories although there are also some unexpected findings. Home learning environment does not play as large a role as was predicted in raising the assessment scores overall for learners while speaking English in the home does, irrespective of ethnic background
    corecore