26 research outputs found

    Photoreceptor Inner Segment Morphology in Best Vitelliform Macular Dystrophy

    Get PDF
    PURPOSE To characterize outer retina structure in best vitelliform macular dystrophy (BVMD) and to determine the effect of macular lesions on overlying and adjacent photoreceptors. METHODS Five individuals with BVMD were followed prospectively with spectral domain optical coherence tomography and confocal and nonconfocal split-detector adaptive optics scanning light ophthalmoscopy (AOSLO). The AOSLO cone photoreceptor mosaic images were obtained within and around retinal lesions. Cone density was measured inside and outside lesions. In 2 subjects, densities were compared with published measurements acquired ∼2.5 years before. One subject was imaged 3 times over a 5-month period. RESULTS The AOSLO imaging demonstrated that photoreceptor morphology within BVMD retinal lesions was highly variable depending on the disease stage, with photoreceptor structure present even in advanced disease. The AOSLO imaging was repeatable even in severe disease over short-time and long-time intervals. Photoreceptor density was normal in retinal areas immediately adjacent to lesions and stable over ∼2.5 years. Mobile disk-like structures possibly representing subretinal macrophages were also observed. CONCLUSION Combined confocal and nonconfocal split-detector AOSLO imaging reveals substantial variability within clinical lesions in all stages of BVMD. Longitudinal cellular photoreceptor imaging could prove a powerful tool for understanding disease progression and monitoring emerging therapeutic treatment response in inherited degenerations such as BVMD

    Hyperfine Suppression of 23S1−33PJ2^3{\rm S}_1 - 3^3{\rm P}_J Transitions in 3^3He

    Full text link
    Two anomalously weak transitions within the 23S1 − 33PJ2 ^3{\rm S}_1~-~3 ^3{\rm P}_J manifolds in 3^3He have been identified. Their transition strengths are measured to be 1,000 times weaker than that of the strongest transition in the same group. This dramatic suppression of transition strengths is due to the dominance of the hyperfine interaction over the fine structure interaction. An alternative selection rule based on \textit{IS}-coupling (where the nuclear spin is first coupled to the total electron spin) is proposed. This provides qualitative understanding of the transition strengths. It is shown that the small deviations from the \textit{IS}-coupling model are fully accounted for by an exact diagonalization of the strongly interacting states.Comment: 4 Pages, 2 figures, 1 table. Accepted for publication in PR

    Nuclear charge radius of 8^8He

    Get PDF
    The root-mean-square (rms) nuclear charge radius of ^8He, the most neutron-rich of all particle-stable nuclei, has been determined for the first time to be 1.93(3) fm. In addition, the rms charge radius of ^6He was measured to be 2.068(11) fm, in excellent agreement with a previous result. The significant reduction in charge radius from ^6He to ^8He is an indication of the change in the correlations of the excess neutrons and is consistent with the ^8He neutron halo structure. The experiment was based on laser spectroscopy of individual helium atoms cooled and confined in a magneto-optical trap. Charge radii were extracted from the measured isotope shifts with the help of precision atomic theory calculations

    Neutrinos

    Get PDF
    229 pages229 pages229 pagesThe Proceedings of the 2011 workshop on Fundamental Physics at the Intensity Frontier. Science opportunities at the intensity frontier are identified and described in the areas of heavy quarks, charged leptons, neutrinos, proton decay, new light weakly-coupled particles, and nucleons, nuclei, and atoms

    The environmental impacts of palm oil in context

    Get PDF
    Delivering the Sustainable Development Goals (SDGs) requires balancing demands on land between agriculture (SDG 2) and biodiversity (SDG 15). The production of vegetable oils, and in particular palm oil, illustrates these competing demands and trade-offs. Palm oil accounts for 40% of the current global annual demand for vegetable oil as food, animal feed, and fuel (210 million tons (Mt)), but planted oil palm covers less than 5-5.5% of total global oil crop area (ca. 425 Mha), due to oil palm’s relatively high yields5. Recent oil palm expansion in forested regions of Borneo, Sumatra, and the Malay Peninsula, where >90% of global palm oil is produced, has led to substantial concern around oil palm’s role in deforestation. Oil palm expansion’s direct contribution to regional tropical deforestation varies widely, ranging from 3% in West Africa to 47% in Malaysia. Oil palm is also implicated in peatland draining and burning in Southeast Asia. Documented negative environmental impacts from such expansion include biodiversity declines, greenhouse gas emissions, and air pollution. However, oil palm generally produces more oil per area than other oil crops, is often economically viable in sites unsuitable for most other crops, and generates considerable wealth for at least some actors. Global demand for vegetable oils is projected to increase by 46% by 20509. Meeting this demand through additional expansion of oil palm versus other vegetable oil crops will lead to substantial differential effects on biodiversity, food security, climate change, land degradation, and livelihoods. Our review highlights that, although substantial gaps remain in our understanding of the relationship between the environmental, socio-cultural and economic impacts of oil palm, and the scope, stringency and effectiveness of initiatives to address these, there has been little research into the impacts and trade-offs of other vegetable oil crops. 65 Greater research attention needs to be given to investigating the impacts of palm oil production 66 compared to alternatives for the trade-offs to be assessed at a global scale

    Assessment of Availability, Teachers’ Proficiency and Challenges of ICT Integration in Teaching Secondary School Mathematics and Science in Bauchi State, Nigeria

    Get PDF
    The study assesses status of integration of Information and Communication Technologies (ICT) in teaching mathematics and science at Public Senior Secondary School in Bauchi Central Educational zone of Bauchi State, Nigeria. The study was aimed to; find out types of available ICT facilities for teaching mathematics and science; establish teacher’s proficiency level of integration of ICT in teaching and learning of Mathematics and Science, and establish challenges faced in the integration of ICT facilities for teaching mathematics and science, Descriptive research design was used for the study. Non Proportional and Purposeful sampling were used for choosing fifty (50) teachers who formed the sample of the study. The sample size was taken from a target population of 250 (20%) mathematics and science teachers. Two instruments were used for data collection. Included were structured and open ended questionnaires and interviews. Data were analyzed using descriptive statistics. Findings revealed high percentage of teacher’s response on the availability of ICT facilities in the study schools, included were white board (74.5 %), laptops (68.6%), printers (56.9%), computer device (50.9%), smart board (50.1 %) and projectors (49.0%). Half (51.0%) of teachers reported internet service and scanning machine not functional. Few teachers (15.7%) reported computers and printers (11.7 %) not functional. Majority (44%) of mathematics and science teachers have a fair knowledge of using ICT facilities to present lesson. Result revealed teachers lack of workshop/seminar on ICT integration (88.2%), students’ ratio to ICT facilities (computers) (86.3%) and lack of time for teachers (58.6%) using ICT during lesson were major challenges. The implication of the study is that effective ICT integration can only be actualized if new initiatives are taken. Thus the study recommended that Mathematics and science teachers should be engaged on professional development training with emphasis on ICT integration in the classroom situation. Stake holders in education sectors and school administrators most ensure effective functions of available ICT facilities in secondary schools
    corecore