The interpretation of wall motion is an important component of echocardiography but remains a source of variation between observers. It has been believed that automated quantification of left ventricular (LV) systolic function by measurement of LV systolic strain from speckle-tracking echocardiography might be helpful. This multicenter study of nearly 250 volunteers without evidence of cardiovascular disease showed an average LV peak systolic strain of -18.6 +/- 0.1%. Although strain was influenced by weight, blood pressure, and heart rate, these features accounted for only 16% of variance. However, there was significant segmental variation of regional strain to necessitate the use of site-specific normal ranges.

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Previous work on the US Atlantic coast has generally shown that coastal foredunes are dominated by two dune grass species, Ammophila breviligulata (American beachgrass) and Uniola paniculata (sea oats). From Virginia northward, A. breviligulata dominates, while U. paniculata is the dominant grass south of Virginia. Previous work suggests that these grasses influence the shape of coastal foredunes in species-specific ways, and that they respond differently to environmental stressors; thus, it is important to know which species dominates a given dune system. The range boundaries of these two species remains unclear given the lack of comprehensive surveys. In an attempt to determine these boundaries, we conducted a literature survey of 98 studies that either stated the range limits and/or included field-based studies/observations of the two grass species. We then produced an interactive map that summarizes the locations of the surveyed papers and books. The literature review suggests that the current southern range limit for A. breviligulata is Cape Fear, NC, and the northern range limit for U. paniculata is Assateague Island, on the Maryland and Virginia border. Our data suggest a northward expansion of U. paniculata, possibly associated with warming trends observed near the northern range limit in Painter, VA. In contrast, the data regarding a range shift for A. breviligulata remain inconclusive. We also compare our literature-based map with geolocated records from the Global Biodiversity Information Facility and iNaturalist research grade crowd-sourced observations. We intend for our literature-based map to aid coastal researchers who are interested in the dynamics of these two species and the potential for their ranges to shift as a result of climate change.

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Abstract-Blood (or plasma) rheology is related to cardiovascular risk. Mechanisms of this association are unclear but may be partially related to impaired left ventricular (LV) function and increased central blood pressure (BP) during light activity. This study aimed to test these hypotheses. Twenty patients (14 men; aged 61Ϯ12 years) with polycythemia rubra vera (nϭ16) or hemochromatosis (nϭ4) were studied at rest and during exercise at Ϸ50% of maximal heart rate before and after venesection (500 mL; volume replaced with saline) to elicit an acute decrease in plasma viscosity at stable BP. Controls (nϭ20) underwent the same protocol with 25-mL venesection. Central BP and augmentation index were determined by tonometry. Resting LV systolic (peak longitudinal systolic strain rate and strain) and diastolic functions were determined by tissue-Doppler echocardiography. Venesection with blood volume replacement decreased viscosity (1.46Ϯ0.10 to 1.41Ϯ0.11 centipoise), protein, and hemoglobin (PϽ0.05 for all) and increased strain rate and strain (PϽ0.001 for both) in patients but not in controls (PϾ0.10 for all). There was no change in LV diastolic function (PϾ0.12 for all Key Words: blood pressure Ⅲ hemodynamics Ⅲ blood viscosity Ⅲ heart ventricles Ⅲ exercise S everal studies have demonstrated associations between blood rheological variables (eg, fibrinogen, hematocrit, blood, and plasma viscosity) and cardiovascular risk factors, including elevated blood pressure (BP), 1 raised carotid intima media thickness, 2 increased aortic pulse wave velocity, 3 incident hypertension, 4 incident cardiovascular disease, 5 and vascular and nonvascular mortality. 6 Few studies have investigated the possible mechanisms behind these associations. Recent data suggest that studying the central (ascending aortic) BP response to exercise may reveal important information relating to left ventricular (LV) function and cardiovascular risk that would otherwise be undetectable under resting conditions. 7 This could be because of the large individual variations that may exist between brachial and central systolic BPs (SBP) during exercise. 8 These changes can be seen even with light-intensity activity, similar to that of daily life. 9,10 Thus, "true" LV afterload may be significantly different between individuals with similar brachial SBP during physical activity.Using radial tonometry to estimate central BP from arterial waveforms, we found recently that men with hypercholesterolemia had significantly elevated augmentation index (AIx) and blunted pulse pressure amplification (ratio of brachial: central pulse pressure) during light exercise. 11 This was representative of increased central systolic loading (possibly affecting normal LV function) and occurred despite similar brachial SBP compared with controls. We hypothesized that this abnormal response may be related to plasma rheology, including factors such as increased viscosity, which may retard peripheral blood runoff and increase exercise AIx. The aim of this current study was to determi...