46 research outputs found

    Quantitative Computed Tomography in COPD: Possibilities and Limitations

    Get PDF
    Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease that is characterized by chronic airflow limitation. Unraveling of this heterogeneity is challenging but important, because it might enable more accurate diagnosis and treatment. Because spirometry cannot distinguish between the different contributing pathways of airflow limitation, and visual scoring is time-consuming and prone to observer variability, other techniques are sought to start this phenotyping process. Quantitative computed tomography (CT) is a promising technique, because current CT technology is able to quantify emphysema, air trapping, and large airway wall dimensions. This review focuses on CT quantification techniques of COPD disease components and their current status and role in phenotyping COPD

    Protective management of trees against debarking by deer negatively impacts bryophyte diversity

    Get PDF
    When wildlife populations become too large, they impact other flora and fauna within the ecosystems that they inhabit. For example, the recent rise in population numbers of sika deer in Japan has led to the stripping of bark from tree overstories in forested areas. This has led to protective management actions, such as wrapping the trunks of trees in wire mesh. The present study investigates the impact of this management action on epiphytic diversity at Mt. Ohdaigahara, which is one of the hotspots for bryophyte diversity in Japan. The correlation between the diversity of epiphytic bryophytes and environmental variables was examined, including the presence/absence of wire mesh protection. A generalized linear model showed that species richness and bryophyte cover was significantly correlated with both tree diameter (at 1.5 m height) and tree density (P < 0.01), but negatively correlated with wire mesh protection. Inductively coupled plasma-mass spectrometry analysis showed a significant 3- to 6-fold higher concentration of zinc in bryophytes occupying tree bark under wire mesh protection than for those without wire mesh. Hence, the high sensitivity of bryophytes to zinc accumulation, as a result of toxicity caused by galvanized iron mesh, has led to the loss of species richness and bryophyte cover on tree trunks. Furthermore, other heavy metals found in wire mesh may also contribute to the negative effect on bryophytes. Therefore, to establish best practices for biodiversity conservation that include bryophytes, materials that are free of heavy metals should be preferentially used for tree protection

    Vulnerabilities of Tropical Forests to Climate Change: The Significance of Resident Epiphytes

    No full text
    Abstract. Predictions about the impacts of climate change on tropical forests require information on the relative vulnerabilities and roles of the biological components of these unusually complex systems. Central to the structure and function of any ecosystem – and the subject of this paper – is its flora, the energetic base for co-occurring heterotrophs. Much data indicate that arboreal flora (the epiphytes), those plants anchored in the forest canopy without access to the ground, occupy unusually climate-defined ecospace compared with co-occurring types such as the supporting trees. This report also describes how the epiphytes influence adjacent biota and whole-system processes, specifically those concerned with energetics, hydrology, and mineral cycling. Second, a mechanistic explanation for the exceptionally climate-sensitive nature of arboreal flora is provided. Finally, points one and two are used to make the case that arboreal flora represent a weak link in the integrity of certain types of forest, especially cloud forest and other types at lower elevations well known for their extraordinarily diverse biota. These plants, more than most, should provide early indications of floristic response to climate change throughout much of the tropics, but particularly in montane regions. 1
    corecore