Heatwave implications for the future of longleaf pine savanna understory restoration.

The longleaf pine (LLP) savanna ecosystem once covered ~ 92 million acres of the Southeast USA, but due to anthropogenic activities such as logging and fire suppression, only 3% of its once widespread historic range remains. While many restoration efforts are underway to conserve this biodiverse ecosystem, restoration must be done in the context of climate change. In the last few decades, heatwaves have increased in frequency and intensity across the Southeastern USA with further increases predicted. To expand our understanding of LLP savanna restoration in light of these changes, we ran a series of three simulated heatwave greenhouse experiments through a Course-based Undergraduate Research Experience (CURE) incorporating ~ 150 undergraduate researchers per experiment. We measured plant growth metrics for four understory grasses commonly used in LLP savanna restoration efforts. We found that while most grass plug individuals survived heatwave conditions, aboveground production was reduced due to heatwaves. This productivity decrease could result in less biomass available for the essential vegetation fire feedback loop, where fire increases grass biomass, and in turn, more grass provides more fuel for fire. These results imply that land managers can proactively compensate for biomass loss due to heatwaves by planting more grass plugs during initial restoration. Supplementary Information: The online version contains supplementary material available at 10.1007/s11258-021-01212-7.

Detection of coronary artery stenosis using 40-channel computed tomography with multi-segment reconstruction.

Coronary angiographic studies performed with 16-channel multidetector computer tomographic scanners have demonstrated accurate detection of coronary vessel stenosis but are limited by a significant number of non-evaluable segments. To date, only single-center experience with multidetector computer tomography has been reported. We performed a prospective, blinded study at 2 institutions to determine the feasibility and diagnostic accuracy of coronary angiography using 40-channel multidetector computer tomography with multi-segment reconstruction for the detection of obstructive coronary artery disease (CAD). Multidetector computer tomographic studies were performed in 85 patients who were referred for invasive coronary angiography with clinically suspected CAD. Datasets were analyzed by blinded, independent review. Of 1,145 segments that were suitable for analysis as determined by angiography, 1,045 (91.3%) were evaluable on multidetector computer tomography. Segment-based sensitivity, specificity, and positive and negative predictive values for detecting > or =50% luminal stenoses were 86%, 97%, 75%, and 97%, respectively. The area under the receiver-operating characteristic curves for the detection of > or =50% angiographic stenosis by multidetector computer tomography was 0.94. In a patient-based analysis, the sensitivity, specificity, and positive and negative predictive values for detecting subjects with > or =1 segment with > or =50% stenosis were 98%, 93%, 94% and 93%, respectively. In conclusion, coronary angiography using 40-channel multidetector computer tomography with multi-segment reconstruction accurately detects coronary segments and patients with obstructive CAD, with a small number of non-evaluable cases.

Cardiac myxoma: imaging features in 83 patients.

Eighty-six cardiac myxomas were reviewed retrospectively for the clinical, pathologic, and radiologic findings. In this series, 83 patients (47 female and 36 male; age range, 2-78 years; mean age, 48 years) had 49 left atrial (60%), 23 right atrial (28%), seven right ventricular (8%), two biatrial, and two cases of multifocal myxomas. Seventy-one (88%) patients were symptomatic. Radiographs of 38 patients with left atrial myxoma showed evidence of mitral valve obstruction in 53%; radiographs of 16 patients with right atrial myxoma demonstrated calcification and cardiomegaly in 56% and 50%, respectively. Computed tomographic (CT) scans of 21 myxomas demonstrated 20 (95%) spherical or ovoid lesions, 16 (76%) with lobular borders. Seventeen (81%) were hypoattenuated; 14 (67%) were heterogeneous. Twenty-eight magnetic resonance (MR) imaging studies of 30 myxomas showed 29 (97%) spherical or ovoid lesions; 26 (87%) had lobular contours and 26 (90%) of 29 had heterogeneous signal intensity on T1-weighted images. Point of attachment was visible in 15 (83%) cases. Cine gradient recalled echo (GRE) MR images of 10 lesions showed low signal intensity in all cases. Most patients with cardiac myxomas have abnormal but usually nonspecific radiographic findings. CT demonstrates intracavitary heterogeneous, hypoattenuated lobular masses. MR imaging shows heterogeneous lobular lesions and usually allows visualization of the point of attachment. Radiologic imaging of these lesions, particularly with multiplanar and cine GRE MR imaging, can provide accurate assessment of the size, location, and point of attachment of these lesions and should assist in surgical planning.