Transverse Beam Spin Asymmetries in Forward-Angle Elastic Electron-Proton Scattering

We have measured the beam-normal single-spin asymmetry in elastic scattering of transversely-polarized 3 GeV electrons from unpolarized protons at Q^2 = 0.15, 0.25 (GeV/c)^2. The results are inconsistent with calculations solely using the elastic nucleon intermediate state, and generally agree with calculations with significant inelastic hadronic intermediate state contributions. A_n provides a direct probe of the imaginary component of the 2-gamma exchange amplitude, the complete description of which is important in the interpretation of data from precision electron-scattering experiments.Comment: 5 pages, 3 figures, submitted to Physical Review Letters; shortened to meet PRL length limit, clarified some text after referee's comment

Strange Quark Contributions to Parity-Violating Asymmetries in the Forward G0 Electron-Proton Scattering Experiment

We have measured parity-violating asymmetries in elastic electron-proton scattering over the range of momentum transfers 0.12 < Q^2 < 1.0 GeV^2. These asymmetries, arising from interference of the electromagnetic and neutral weak interactions, are sensitive to strange quark contributions to the currents of the proton. The measurements were made at JLab using a toroidal spectrometer to detect the recoiling protons from a liquid hydrogen target. The results indicate non-zero, Q^2 dependent, strange quark contributions and provide new information beyond that obtained in previous experiments.Comment: 5 pages, 2 figure

The G0 Experiment: Apparatus for Parity-Violating Electron Scattering Measurements at Forward and Backward Angles

In the G0 experiment, performed at Jefferson Lab, the parity-violating elastic scattering of electrons from protons and quasi-elastic scattering from deuterons is measured in order to determine the neutral weak currents of the nucleon. Asymmetries as small as 1 part per million in the scattering of a polarized electron beam are determined using a dedicated apparatus. It consists of specialized beam-monitoring and control systems, a cryogenic hydrogen (or deuterium) target, and a superconducting, toroidal magnetic spectrometer equipped with plastic scintillation and aerogel Cerenkov detectors, as well as fast readout electronics for the measurement of individual events. The overall design and performance of this experimental system is discussed.Comment: Submitted to Nuclear Instruments and Method

Strange Quark Contributions to Parity-Violating Asymmetries in the Forward G0 Electron-Proton Scattering Experiment

We have measured parity-violating asymmetries in elastic electron-proton scattering over the range of momentum transfers 0.12 ≤ Q2 ≤ 1.0 GeV2. These asymmetries, arising from interference of the electromagnetic and neutral weak interactions, are sensitive to strange quark contributions to the currents of the proton. The measurements were made at JLab using a toroidal spectrom- eter to detect the recoiling protons from a liquid hydrogen target. The results indicate non-zero, Q2 dependent, strange quark contributions and provide new information beyond that obtained in previous experiments

Ecological profiles of Ghanaian forest trees

Textual summaries are presented of the ecology of most forest trees which in Ghana attain 5 cm dbh. For rarer and smaller trees, the text is reduced to little more than name and brief ecological group, but for others information is presented under various headings relating to tree distribution and regeneration ecology, taxonomy, and miscellaneous other notes. 1260 charts are included, summarising aspects of the ecology in Ghana of 210 of the most important species (including some few-species groups). A series of five charts summarises abundance across Ghana's forest zone, stratified into 21 broad landscape and forest type categories. A sixth chart summarises for each of the 210 important species trends of crown exposure. The crown exposure charts are potentially of value as objective indices of the extent to which each species is a 'light-demander', or 'shade-bearer', and how this changes with tree size. The potential use, origin and explanation of these summaries is explained first in an introductory section.</p

Second Chance

This publication may contain explicit sexual literary descriptions and/or artistic depictions.September 199

Ecological profiles of Ghanaian forest trees

Textual summaries are presented of the ecology of most forest trees which in Ghana attain 5 cm dbh. For rarer and smaller trees, the text is reduced to little more than name and brief ecological group, but for others information is presented under various headings relating to tree distribution and regeneration ecology, taxonomy, and miscellaneous other notes. 1260 charts are included, summarising aspects of the ecology in Ghana of 210 of the most important species (including some few-species groups). A series of five charts summarises abundance across Ghana's forest zone, stratified into 21 broad landscape and forest type categories. A sixth chart summarises for each of the 210 important species trends of crown exposure. The crown exposure charts are potentially of value as objective indices of the extent to which each species is a 'light-demander', or 'shade-bearer', and how this changes with tree size. The potential use, origin and explanation of these summaries is explained first in an introductory section.</p

Woody plants of Western African forests, A guide to the forest trees, shrubs and lianes from Senegal to Ghana

A guide to the identification of all the woody plants (c. 2,250 species in 740 genera) of the forest region of West Africa called 'Upper Guinea', between Togo and Senegal. Upper Guinea is one of the world's most important centres of biodiversity, from the mountain forests of Liberia, Guinea and Sierra Leone, to the lowland evergreen, and semideciduous forests widespread also in Ghana and Ivory Coast