3,998 research outputs found

    Effect of woodstack structure on invertebrate abundance and diversity

    Get PDF
    Reduced quantities of dead wood in managed forests have resulted in a reduction in the abundance and diversity of saproxylic invertebrates to the extent that many are now considered red list species. To mitigate against this loss, one conservation measure is the provision of dead wood, in the form of piles of chopped logs, i.e. ‘woodstacks’. The heterogeneity and volume of dead wood habitat is considered to be an important component of habitat suitability. However, the value of different woodstack types to invertebrate conservation has rarely been quantified and there is little consensus on how to best to survey the invertebrate fauna of woodstacks. This study used both sticky traps and pitfall traps to sample the invertebrate fauna of three types of sycamore woodstack. Woodstacks were made from 10 logs, 20 logs and 10 scorched logs plus a control woodstack made of unplasticised polyvinyl chloride (uPVC) plastic piping and observed over a 4-week period. A total of 1446 invertebrates from 16 orders, including 127 Coleoptera, were caught during the sampling period. A generalized linear model was used to analyse invertebrate abundance between woodstack and between trap types, and diversity was determined using Shannon diversity indices and analysed using a two-way Analysis of Variance (ANOVA). The woodstack type had no effect on the abundance of invertebrates. However, Shannon diversity was highest on the scorched woodstacks, with little difference between the 10 and 20 log stacks and the control uPVC woodstacks. However, closer inspection of orders revealed the uPVC woodstacks to have the lowest abundance and diversity of Coleoptera. This study suggests that constructing woodstacks can provide suitable habitat for a variety of invertebrates. However, these invertebrates may have simply used the structures for shelter and the true value with saproxylic invertebrates could not be measured in this 4-week study. To fully appreciate the conservation value of woodstacks will require longer term studies that examine how and when saproxylic invertebrates use dead and decaying wood

    Radiometric correction procedure study

    Get PDF
    A comparison of MSS radiometric processing techniques identified as a preferred radiometric processing technique a procedure which equalizes the mean and standard deviation of detector-specific histograms of uncalibrated scene data. Evaluation of MSS calibration data demonstrated that the relationship between detector responses is essentially linear over the range of intensities typically observed in MSS data, and that the calibration wedge data possess a high degree of temporal stability. An analysis of the preferred radiometric processing technique showed that it could be incorporated into the MDP-MSS system without a major redesign of the system, and with minimal impact on system throughput

    Investigation of X-ray indications in GOX LINE weld

    Get PDF
    X-ray indications in gaseous oxygen line longitudinal weld and effect on properties of tubin

    Metallurgical analysis of handling tool forward booster assembly

    Get PDF
    Metallurgical analysis of handling tool lifting eye weldment and surface crack formatio

    The Tropes We Tutor By: Names and Labels as Tropes in Writing Center Work

    Get PDF
    The following study explores the way names and labels function as tropes in writing center work. Building on Lakoff and Johnson’s work on metaphors, and using Kenneth Burke’s concept of the trope, this study analyzes the way names and labels for writing center spaces, people, activity, and preparation function metaphorically, synecdochically, metonymically, and ironically to shape the way people understand and value writing centers. This study demonstrates the ways in which names and labels used in writing center work both focus attention on particular aspects of that work and also minimize or hide other important aspects of that work. Ultimately, this study argues that the names and labels currently in use do not accurately reflect writing center work, and encourages scholars of writing center studies to either fully extend labels in use or adopt new labels. The final chapter suggests a framework by which those in writing center studies can select and articulate metaphors ethically, consciously, and with purpose

    Gender differences in conceptual understanding of Newtonian mechanics: a UK cross-institution comparison

    Full text link
    We present results of a combined study from three UK universities where we investigate the existence and persistence of a performance gender gap in conceptual understanding of Newtonian mechanics. Using the Force Concept Inventory, we find that students at all three universities exhibit a statistically significant gender gap, with males outperforming females. This gap is narrowed but not eliminated after instruction, using a variety of instructional approaches. Furthermore, we find that before instruction the quartile with the lowest performance on the diagnostic instrument comprises a disproportionately high fraction (~50%) of the total female cohort. The majority of these students remain in the lowest-performing quartile post-instruction. Analysis of responses to individual items shows that male students outperform female students on practically all items on the instrument. Comparing the performance of the same group of students on end-of-course examinations, we find no statistically significant gender gaps.Comment: 17 page

    VERTICAL IMPACT FORCE AND LOADING RATE ON THE GYMNASTICS TABLE VAULT

    Get PDF
    The purpose of this study was to determine the effect of low and high intensity impact forces on the average loading rate during a forward handspring vault. Peak force, time to peak and impulse were used to characterize the impact vertical force during a vault performed by 12 female gymnasts. Reaction forces from right and left hands were measured at 500 Hz with two PASCO portable force platforms fixed to the vault table surface. Force data were split in two groups: Low intensity (LI: peak forces 0.7 BW). Significant differences (
    • …
    corecore