2,024 research outputs found

    Systematics and Palynology of Picrodendron Further Evidence for Relationship with the Oldfieldioideae (Euphorbiaceae)

    Get PDF
    Although known to botanical science for 285 years, the genus Picrodendron Planchon has been poorly understood for most of this time. The most pervasive problem has been that of discerning familial relationships, and there have been additional difficulties in typifying the generic name (Hayden & Reveal, 1980) and in distinguishing its three nominate species. This paper provides a systematic treatment for Picrodendron and demonstrates its relationships with Euphorbiaceae subfam. Oldfieldioideae Kohler & Webster as evidenced by data on gross morphology, palynology, anatomy, and cytology

    New measurement of the scattering cross section of slow neutrons on liquid parahydrogen from neutron transmission

    Get PDF
    Liquid hydrogen is a dense Bose fluid whose equilibrium properties are both calculable from first principles using various theoretical approaches and of interest for the understanding of a wide range of questions in many body physics. Unfortunately, the pair correlation function g(r)g(r) inferred from neutron scattering measurements of the differential cross section dσdΩd\sigma \over d\Omega from different measurements reported in the literature are inconsistent. We have measured the energy dependence of the total cross section and the scattering cross section for slow neutrons with energies between 0.43~meV and 16.1~meV on liquid hydrogen at 15.6~K (which is dominated by the parahydrogen component) using neutron transmission measurements on the hydrogen target of the NPDGamma collaboration at the Spallation Neutron Source at Oak Ridge National Laboratory. The relationship between the neutron transmission measurement we perform and the total cross section is unambiguous, and the energy range accesses length scales where the pair correlation function is rapidly varying. At 1~meV our measurement is a factor of 3 below the data from previous work. We present evidence that these previous measurements of the hydrogen cross section, which assumed that the equilibrium value for the ratio of orthohydrogen and parahydrogen has been reached in the target liquid, were in fact contaminated with an extra non-equilibrium component of orthohydrogen. Liquid parahydrogen is also a widely-used neutron moderator medium, and an accurate knowledge of its slow neutron cross section is essential for the design and optimization of intense slow neutron sources. We describe our measurements and compare them with previous work.Comment: Edited for submission to Physical Review

    A kapwa-infused paradigm in teaching Catholic theology/catechesis in a multireligious classroom in the Philippines

    Get PDF
    The increasing religious diversity in educational space has raised a legitimate question on how Catholic theology/ catechesis must be taught in Philippine Catholic universities given the institutional mandate to educate students “into the faith of the Church through teaching of Christian doctrine in an organic and systematic way” (Wuerl, 2013, 1). On this note, the paper makes reference to “centered plural- ism” (CP), a positional posture espoused by Georgetown University in dealing with this predicament. In an attempt to (re) appropriate CP into local context, there is a need to explore the Filipino conception of self/others as enveloped within the indigenous concept of kapwa. Hereon, the paper finds that CP is not just feasibly suitable in local context but with kapwa's more inclusive description of the relationship of self and others, a CP‐based teaching paradigm in theology/ catechesis is a promising project in the educational scene of the Philippines

    Distracted , Stressed, and Confused: The Effects of Distraction and Stress on Memory Retention

    Get PDF
    Previous research has tested the effects of test anxiety and memory impairment due to stress, but little research has investigated the interplay of these factors with environmental distraction. Our study aims to fill in this gap by examining the association between distraction, stress and information recall in an effort to identify optimal testing experiences within the academic environment. Professors and administrators can improve academic success based upon the knowledge of how stressful stimuli affects test performance. In this experiment, we seek to establish a connection between stress, distraction, and memory recall within academic testing. By employing distracting stimuli in a controlled environment, we hope to uncover further insight into whether students perform better or worse in stressful environments. Understanding how added stressors influence student performance can help professors and administrators structure effective learning environments. Likewise, our findings might also add to our knowledge of the influence of marginal distractibility on the recall of class content. We speculate that there is an optimal range of distractibility and stress within the academic setting. Understanding how added stressors and distractions influence student performance can help college administrators structure effective learning environments. During the experimental phase, our team examined the effects of stress on material recollection by using a graded versus an ungraded exam. We expected that the combination of stress and distracted conditions will result in a significantly diminished student memory performance, compared to the marginal declines caused by stress or distraction alone. Additionally, we explored the role of environmental distraction on memory performance by measuring how students responded to the sudden announcement of a graded test. We hypothesized that if a sudden stressor is presented, one will respond negatively, unable to recall the desired information. Thus, we expect the student to perform less successfully as one would without the stressor. We suspected that environmental noise and distractions increased, academic anxiety will increase as well, causing memory deficits for the affected students. Findings are under review, but are expected to support the stated hypotheses

    One-pot homologation of boronic acids : a platform for diversity-oriented synthesis

    Get PDF
    Formal homologation of sp2-hybridized boronic acids is achieved via cross-coupling of boronic acids with conjunctive haloaryl BMIDA components in the presence of a suitably balanced basic phase. The utility of this approach to provide a platform for diversity-oriented synthesis in discovery medicinal chemistry is demonstrated in the context of the synthesis of a series of analogues of a BET bromodomain inhibitor

    First Observation of PP-odd Îł\gamma Asymmetry in Polarized Neutron Capture on Hydrogen

    Full text link
    We report the first observation of the parity-violating 2.2 MeV gamma-ray asymmetry AÎłnpA^{np}_\gamma in neutron-proton capture using polarized cold neutrons incident on a liquid parahydrogen target at the Spallation Neutron Source at Oak Ridge National Laboratory. AÎłnpA^{np}_\gamma isolates the ΔI=1\Delta I=1, \mbox{3S1→3P1^{3}S_{1}\rightarrow {^{3}P_{1}}} component of the weak nucleon-nucleon interaction, which is dominated by pion exchange and can be directly related to a single coupling constant in either the DDH meson exchange model or pionless EFT. We measured AÎłnp=[−3.0±1.4(stat)±0.2(sys)]×10−8A^{np}_\gamma = [-3.0 \pm 1.4 (stat) \pm 0.2 (sys)]\times 10^{-8}, which implies a DDH weak πNN\pi NN coupling of hπ1=[2.6±1.2(stat)±0.2(sys)]×10−7h_{\pi}^{1} = [2.6 \pm 1.2(stat) \pm 0.2(sys)] \times 10^{-7} and a pionless EFT constant of C3S1→3P1/C0=[−7.4±3.5(stat)±0.5(sys)]×10−11C^{^{3}S_{1}\rightarrow ^{3}P_{1}}/C_{0}=[-7.4 \pm 3.5 (stat) \pm 0.5 (sys)] \times 10^{-11} MeV−1^{-1}. We describe the experiment, data analysis, systematic uncertainties, and the implications of the result.Comment: 6 pages, 5 figure
    • 

    corecore