34 research outputs found
Climate Change and the Potential Distribution of an Invasive Shrub, Lantana camara L
The threat posed by invasive species, in particular weeds, to biodiversity may be exacerbated by climate change. Lantana camara L. (lantana) is a woody shrub that is highly invasive in many countries of the world. It has a profound economic and environmental impact worldwide, including Australia. Knowledge of the likely potential distribution of this invasive species under current and future climate will be useful in planning better strategies to manage the invasion. A process-oriented niche model of L. camara was developed using CLIMEX to estimate its potential distribution under current and future climate scenarios. The model was calibrated using data from several knowledge domains, including phenological observations and geographic distribution records. The potential distribution of lantana under historical climate exceeded the current distribution in some areas of the world, notably Africa and Asia. Under future scenarios, the climatically suitable areas for L. camara globally were projected to contract. However, some areas were identified in North Africa, Europe and Australia that may become climatically suitable under future climates. In South Africa and China, its potential distribution could expand further inland. These results can inform strategic planning by biosecurity agencies, identifying areas to target for eradication or containment. Distribution maps of risk of potential invasion can be useful tools in public awareness campaigns, especially in countries that have been identified as becoming climatically suitable for L. camara under the future climate scenarios
Speckle Tracking Echocardiography Identifies Impaired Longitudinal Strain as a Common Deficit in Various Cardiac Diseases
The use of speckle-tracking echocardiography (STE) is becoming an increasingly useful tool in the evaluation of myocardial disease. STE software can track the motion of the specular pattern created by the interference of ultrasound with the myofibers of the heart and provide a quantitative means to evaluate subtle changes in ventricular function that often occur before changes in ventricular ejection fraction are observed. STE is most often used to measure the change in shape (strain) of myocardial segments in the circumferential, radial, and longitudinal directions. In various diseases, including coronary artery disease, aortic stenosis, and mitral regurgitation, deficits in longitudinal strain appear to occur earlier than deficits in other measures of strain or in ejection fraction. Consideration of STE measures of left ventricular contraction has the potential to significantly affect clinical management and outcomes of ischemic and valvular heart disease given the ability to separate those with asymptomatic disease who may benefit from earlier interventions than current guidelines may suggest