Evidence of nest material kleptoparasitism in Worm-eating Warblers (Helmitheros vermivorum) in east-central Arkansas, USA.

Nest material kleptoparasitism likely evolved in birds to reduce the cost of searching for and collecting material themselves. Although nest material kleptoparasitism has been reported commonly in colonially nesting species, reports for solitary breeding species are infrequent, especially for neotropical migratory species. Here, we report potential and actual nest material kleptoparasitism in the Worm-eating Warbler (Helmitheros vermivorum). We deployed video camera systems at passerine nests (n = 81) in east-central Arkansas during summers 2011-2012. In one video, we observed a Worm-eating Warbler stealing nesting material from a Hooded Warbler (Setophaga citrina) nest. One day later, we later observed a Worm-eating Warbler landing within 0.5 m of the same warbler nest when the female was incubating, which possibly deterred a second theft of nesting material. In a third video recording, we observed another Worm-eating Warbler landing within 1 m of an Indigo Bunting (Passerina cyanea) nest. As far as we could determine, neither of these latter two nest visits resulted in nest material kleptoparasitism. Potential benefits of nest material kleptoparasitism include reduced competition for limited nest materials, easy access to suitable material, reduced travel distance, and reduction of nest predation risk; however, costs include risk of attack by host or introducing parasites to one's nest. Importantly, this behavior could ultimately affect the behavioral and life history evolution of a species. We suggest further work should be conducted to determine the prevalence of nest material kleptoparasitism in Worm-eating Warblers and other solitary breeding passerines, including efforts to quantify the benefits and costs of this behavior.

Correction: Does flooding effect the apparent survival and body condition of a ground foraging migrant passerine?

[This corrects the article DOI: 10.1371/journal.pone.0175179.].

Does flooding effect the apparent survival and body condition of a ground foraging migrant passerine?

Natural disturbances play a fundamental role in maintaining habitat and landscape heterogeneity; however, these events can also have negative effects on some species. While we know that disturbances can reduce habitat quality for many species, leading to diminished populations and altered community structure, the effect of these events on individuals that continue to occupy affected areas remains unknown. We focused on understanding the impact of flood-mediated reduction of habitat quality on Swainson's Warblers (Limnothlypis swainsonii). In 2008, a catastrophic flood event occurred on the Mississippi River and its tributaries, severely affecting one of two locations where we had studied territorial males since 2004. To determine the impact of flooding on this species, we evaluated how body condition and apparent survival of males differed between locations and in pre-flood (2004-2007) and post-flood (2008-2010) periods. Body condition did not differ between locations after the flood, suggesting that flooding did not cause food limitation for this obligate ground forager. Apparent survival in the post-flood period was lower at both locations and led to near population extirpation at the heavily flood-impacted site. Overall, this study demonstrates the vulnerability of species to extreme hydrological events, an increasing threat due to climate change. Future research should focus on identifying species that are vulnerable to these events and determining appropriate conservation strategies. Conservation for the Swainson's Warbler should focus on identifying and conserving the highest elevation, least flood prone areas within bottomland hardwood forests and managing those areas for thick understory vegetation.

The emergence densities of annual cicadas (Hemiptera: Cicadidae) increase with sapling density and are greater near edges in a bottomland hardwood forest.

The emergence densities of cicadas tend to be patchy at multiple spatial scales. While studies have identified habitat conditions related to these patchy distributions, their interpretation has been based primarily on periodical cicada species; habitat factors associated with densities of nonperiodical (i.e., annual) cicadas have remained under studied. This is despite their widespread distribution, diversity, and role as an important trophic resource for many other organisms, particularly within riparian areas. We studied habitat factors associated with the emergence densities of Tibicen spp. in a bottomland hardwood forest in east-central Arkansas. We found emergence densities were greatest in areas of high sapling densities and increased toward forest edges, although sapling density was a much stronger predictor of emergence density. Emergence densities also differed among sample areas within our study system. The habitat features predicting nymph densities were likely driven by a combination of factors affecting female selection of oviposition sites and the effects of habitat conditions on nymph survival. The differences in nymph densities between areas of our system were likely a result of the differential effects of flooding in these areas. Interestingly, our findings were similar to observations of periodical species, suggesting that both types of cicadas select similar habitat characteristics for ovipositing or are under comparable selective pressures during development. Our findings also imply that changes in habitat characteristics because of anthropogenically altered disturbance regimes (e.g., flooding) have the potential to negatively impact both periodical and annual species, which could have dramatic consequences for organisms at numerous trophic levels.

Exertional myopathy in pileated woodpeckers (Dryocopus pileatus) subsequent to capture.

Out of 33 Pileated Woodpeckers (Dryocopus pileatus) captured and fitted with radio-transmitters, 12 were later found dead. Three carcasses were recovered and submitted for necropsy. One bird had large pale foci in multiple muscles. Microscopically, skeletal muscle in all three had evidence of severe coagulative necrosis, consistent with capture myopathy.

Identifying predators clarifies predictors of nest success in a temperate passerine.

1. Nest predation negatively affects most avian populations. Studies of nest predation usually group all nest failures when attempting to determine temporal and parental activities, habitat or landscape predictors of success. Often these studies find few significant predictors and interpret patterns as essentially random. 2. Relatively little is known about the importance of individual predator species or groups on observed patterns of nest success, and how the ecology of these predators may influence patterns of success and failure. 3. In 2006 and 2007, time-lapse, infrared video systems were deployed at nests of Swainson's warblers (Limnothlypis swainsonii Audubon) in east-central Arkansas to identify dominant nest predators and determine whether factors predicting predation differed among these predators. 4. Analysis of pooled data yielded few predictors of predation risk, whereas separate analyses for the three major predator groups revealed clear, but often conflicting, patterns. 5. Predation by ratsnakes (Elaphe obsoleta) and raptors was more common during the nestling period, whereas predation by brown-headed cowbirds (Molothrus ater) occurred more during incubation. Additionally, the risk of predation by raptors and cowbirds decreased throughout the breeding season, whereas ratsnake predation risk increased. 6. Contrary to expectations, predation by ratsnakes and cowbirds was more common far from edges, whereas raptor predation was more common close to agricultural edges. 7. Collectively, our results suggest that associating specific predators with the nests they prey on is necessary to understand underlying mechanisms.

Use of real-time 3-dimensional transthoracic echocardiography in the evaluation of mitral valve disease.

Three-dimensional (3D) echocardiography (3DE) provides unique orientations of the mitral valve (MV) not obtainable by routine 2-dimensional echocardiography. However, this modality has not been adopted in routine clinical practice because of its cumbersome and time-consuming process. The recent introduction of a full matrix-array transducer has enabled online real-time 3DE (RT3DE) and rendering. This study was designed to: (1) determine the clinical use of RT3DE in patients with MV pathology and in a control group selected for their good acoustic windows (protocol I); and (2) to investigate the feasibility of imaging the MV apparatus in a large group of consecutively imaged patients to determine the acoustic window or perspective from which the MV leaflets, commissures, and orifice are best visualized (protocol II). In protocol I, 65 patients were selected based on MV pathology and good 2-dimensional echocardiography image quality. Protocol II included 150 patients who were consecutively imaged using RT3DE. Images were viewed online (protocol I) and offline on a digital review station (protocol II). RT3DE visualization of the MV apparatus was graded based on the percentage of leaflet dropout and definition. In protocol I, 78% of patients had adequate 3D MV reconstructions with complete visualization of the anterior mitral leaflet (AML) in 84% versus the posterior mitral leaflet (PML) in 77%. The mitral leaflets, commissures, and MV orifice were well seen in 98%; however, the submitral apparatus was only observed in 76% of the patients. RT3DE: (1) correctly identified the prolapsed/flailed scallop in 6 of 8 patients; (2) obtained en face orientation of the MV orifice in 9 of 11 patients with mitral stenosis, allowing accurate measurements of the orifice area and evaluation of the immediate effects of balloon mitral valvuloplasty; and (3) allowed postoperative evaluation of MV repair and the integrity of the struts of a bioprosthetic leaflet. In protocol II, 70% of patients had adequate RT3DE with complete visualization of the AML noted in 55% versus 51% for PML. The mitral leaflets, commissures, and MV orifice were observed in 69%. Irrespective of acquisition window, the AML was best seen from a ventricular perspective. In contrast, the PML was optimally examined from a parasternal window. Both the medial and lateral commissures were equally assessed from either imaging window. In conclusion, RT3DE of the MV is feasible in a large majority of patients. Using different MV acquisitions RT3DE provides important clinical information such as: (1) identification of a prolapsed/flail scallop; (2) measurement of stenotic valve areas; (3) evaluation of MV leaflet integrity postrepair; and (4) identification of a MV perforation. In general the AML is better visualized than the PML. The parasternal window is the optimal approach to visualize both AML and PMLs.

Automated border detection on contrast enhanced echocardiographic images.

BACKGROUND: Accurate determination of left ventricular ejection fraction (LV EF) is of paramount importance in the evaluation of patients with cardiovascular disease. Quantitative techniques for the automated calculation of EF exist however, the robustness of these techniques is dependent on adequate endocardial border definition and therefore are difficult to use in patients with limited images. We sought to combine the endocardial border enhancing effects of contrast echocardiography with an automated border detection technique to provide quantitative and accurate determination of LV EF. METHODS: Thirty-nine consecutive patients referred to nuclear cardiology for EF determination underwent radionuclide angiography followed by echocardiographic imaging using prototype software that allowed automated border detection during contrast infusion. RESULTS: Adequate LV cavity opacification with contrast was possible in 38/39 patients. The mean radionuclide EF was 50+/-16% (range 19-73). There was no statistically significant difference between the mean nuclear EF and averaged echocardiographically determined EF (51+/-18%). The mean bias was 0.6 with limits of agreement that were +15 and -14. CONCLUSION: This study demonstrated that prototype software successfully tracked the contrast enhanced endocardial border allowing accurate calculation of LV EF.

Automated quantitative assessment of wall motion in patients with poor acoustic windows.

BACKGROUND: No technique exists for objective evaluation of left ventricular wall motion in contrast-enhanced images. We tested a new technique for quantification of regional fractional area change using contrast-enhanced power modulation imaging with color kinesis. METHODS: The feasibility of this technique for detecting acute ischemia was first tested in 11 pigs. Next, the accuracy for detecting resting wall-motion abnormalities was determined in 52 patients requiring contrast and compared with conventional interpretation of 2-dimensional images by inexperienced readers. Expert interpretation of 2-dimensional images served as the gold standard. RESULTS: In pigs, coronary occlusion resulted in reversible hypokinesis and reduced regional fractional area change. In patients with poor acoustic windows, this technique's accuracy for quantitative detection of resting wall-motion abnormalities was 86% compared with 81% for conventional interpretation by inexperienced readers (P <.01). CONCLUSIONS: Regional wall motion can be accurately assessed using color-encoded power modulation imaging for patients requiring contrast. This technique may prove a useful diagnostic aid to echocardiographers of varying levels of experience.

Implementing contrast echocardiography in the laboratory.

Contrast echocardiography is an important and a significant addition to a modern echocardiography laboratory. Its successful implementation is dependent on a team approach between sonographers, nurses, and physicians. A practical plan is one that includes a proper understanding of indications, logistical matters, technical and performance standards, and reimbursement issues.

Differential diagnosis of cardiac masses using contrast echocardiographic perfusion imaging.

OBJECTIVES: We investigated the usefulness of echocardiographic contrast perfusion imaging in differentiating cardiac masses. BACKGROUND: Two-dimensional echocardiography is the primary diagnostic modality for cardiac masses. However, differentiation between the different types of cardiac masses may be difficult at times. We hypothesized that echocardiographic contrast perfusion imaging would differentiate the neo-vascularization of malignancies from the avascularity of thrombi and the sparse vascularity of stromal tumors. METHODS: Sixteen patients with cardiac masses underwent power-modulation imaging after echocardiographic intravenous contrast administration. Pixel intensities in the mass and an adjacent section of myocardium were analyzed visually and by dedicated software. All masses had a pathologic diagnosis or resolved after anticoagulation. In a subset of patients, video-intensity curves of contrast replenishment in the mass and myocardium over time were generated. The post-impulse steady-state pixel intensity (A) and initial rate of contrast replenishment after impulse (beta) were compared with an index of blood vessel area on pathology. RESULTS: In seven of 16 patients, contrast enhancement resulted in greater pixel intensity in the mass than in the adjacent myocardium. All of these masses were classified pathologically as malignant (n = 6) or benign and vascular (n = 1). Nine masses demonstrated decreased pixel intensity, compared with the myocardium, and were diagnosed pathologically as myxomas (n = 2) or thrombi (n = 5), or they resolved with anticoagulation (n = 2). For the subset of patients, beta correlated with the vessel area index (r = 0.60). CONCLUSIONS: Echocardiographic contrast perfusion imaging aids in the differentiation of cardiac masses. Compared with the adjacent myocardium, malignant and vascular tumors hyper-enhanced, whereas stromal tumors and thrombi hypo-enhanced.

Normal values of left ventricular systolic and diastolic function derived from signal-averaged acoustic quantification waveforms: a multicenter study.

Automated border-detection techniques such as acoustic quantification have proven accurate and useful for quantifying left ventricular (LV) function. We acquired LV acoustic quantification waveforms from the parasternal short-axis window in 140 healthy patients in the age range of 16 to 78 years. Signal-averaged waveforms were analyzed for parameters of systolic and diastolic performance. The average fractional area change was 54 +/- 12%, and there were no significant changes in LV systolic function in the age range studied. There were significant changes in diastolic parameters with aging. The percentage of contribution to total LV filling occurring during atrial filling nearly tripled during the 6 decades studied, from 13% in the youngest cohort to 36% in the eighth decade of life. This study provides normal reference values for systolic and diastolic parameters of LV function determined from signal-averaged acoustic quantification waveforms acquired from the parasternal short-axis view in adult and adolescent patients over a wide age range.

Biplane stress echocardiography using a prototype matrix-array transducer.

BACKGROUND: Rapid image acquisition after cessation of exercise is essential for accurate stress echocardiography. Recently, a prototype matrix-array transducer has been developed that allows simultaneous acquisition of 2 imaging planes (biplane [BP] imaging). METHODS: In all, 19 healthy volunteers underwent 2 separate stress echocardiographic studies. Images were acquired in traditional 2-dimensional or BP format pre-exercise and postexercise. RESULTS: Total image acquisition time for 2-dimensional stress echocardiography was 38 +/- 8 seconds versus 29 +/- 8 seconds for BP imaging (P <.05). Heart rates were acquired closer to age-predicted maximum with BP imaging in the apical 3- and 2-chamber and parasternal long- and short-axis views (82%, 75%, 70%, 70% for BP vs 76%, 72%, 68%, 66% for 2-dimensional, respectively). CONCLUSION: BP imaging using a recently developed matrix-array probe allows more rapid imaging postexercise, resulting in acquisition of poststress images at higher heart rates without compromising image quality.

Dynamic three-dimensional color flow Doppler: an improved technique for the assessment of mitral regurgitation.

BACKGROUND: Prior studies have reconstructed mitral regurgitant flow in three dimensions displaying gray scale renditions of the jets, which were difficult to differentiate from surrounding cardiac structures. Recently, a color-coded display of three-dimensional (3D) regurgitant flow has been developed. However, this display was unable to integrate cardiac anatomy, thereby losing spatial information, which made it difficult to determine the jet origin and its spatial trajectory. To overcome this limitation, an improved method of 3D color reconstruction of regurgitant jets obtained from color flow Doppler using a transesophageal approach was developed to allow the combined display of both color flow and gray scale information. OBJECTIVES: To demonstrate the feasibility of 3D reconstruction of regurgitant mitral flow jets using an improved method of color encoding digital data acquired by transesophageal echocardiography (TEE). METHODS: We studied 46 patients undergoing a clinically indicated TEE study. All subjects had mitral regurgitation detected on a previous transthoracic study. Atrial fibrillation or poor image quality were not used as exclusion criteria. The 3D study was performed using a commercial ultrasound imaging system with a TEE probe (Sonos 5500, Agilent Technologies). A rotational mode of acquisition was used to collect two-dimensional (2D) color flow images at 3-degree intervals over 180 degrees. Images were processed off line using the Echo-View Software (TomTec Imaging Systems). Volume-rendered 3D color flow jets were displayed along with gray scale information of the adjacent cardiac structures. RESULTS: Mitral regurgitant flow, displayed in left atrial and two longitudinal orientations, was successfully reconstructed in all patients. The time for acquisition, post-processing, and rendering ranged between 10 and 15 minutes. There were 28 centrally directed jets and 15 eccentric lesions. Eight patients in the study had periprosthetic mitral regurgitant flow. CONCLUSIONS: Three-dimensional imaging of mitral regurgitant jets is feasible in the majority of patients. This improved technique provides additional information to that obtained from the 2D examination. Particularly, in patients with paravalvular leaks 3D color flow Doppler provides information on the origin and the extent of the dehiscence, as well as insight into the jet direction. In addition, in patients with eccentric mitral regurgitation, this new modality overcomes the inherent limitations of 2D echo Doppler by depicting the full extent of the jet trajectory.

Quantitative diagnosis of apical cardiomyopathy using contrast echocardiography.

BACKGROUND: The echocardiographic diagnosis of apical hypertrophic cardiomyopathy (ACM) has been limited by the frequent inability to visualize the apical endocardium. We hypothesized that the use of contrast agents in patients with suspected ACM, but nondiagnostic echocardiographic studies, would allow quantitative diagnosis. METHODS: Contrast enhancement was performed in 26 patients with nondiagnostic transthoracic echocardiograms (TTEs) for the diagnosis of ACM; 6 patients with suspected ACM based on unexplained symmetric precordial T-wave inversions and increased apical tracer uptake on single-photon emission computed tomography (SPECT) scans, 10 patients with normal electrocardiogram (ECG) readings and no history of hypertension (healthy group), and 10 patients with hypertension and ECG criteria for left ventricular hypertrophy (LVH group). Images were obtained with Optison (Mallinckrodt Medical; IV, 1.0 mL) using harmonic imaging and low mechanical index. Posterior (PW) and septal wall (SW) thicknesses were measured at end-diastole in the parasternal long-axis view. Apical wall thickness (A) was measured from the contrast-enhanced apical endocardium to the visceral epicardial surface in the apical 4-chamber view. A/PW and A/SW ratios were calculated for each group. Asymmetric apical hypertrophy was defined as an A/PW ratio greater than 1.5. RESULTS: Contrast-enhanced apical thickness was greater than 2.0 cm in all patients in the suspected ACM group but less than 1.2 cm in all patients in the LVH and healthy groups. In all 6 patients in the suspected ACM group, A/PW and A/SW ratios were greater than 1.5. No patient in the healthy or LVH groups had thickness ratios greater than 0.85. CONCLUSION: Contrast echocardiography allows quantitative diagnosis of ACM in patients with suggestive ECG and SPECT but nondiagnostic TTEs. This study suggests that contrast echocardiography should be performed before using more expensive or invasive diagnostic testing for this condition.

Objective assessment of left ventricular wall motion from contrast-enhanced power modulation images.

There is no method to objectively evaluate left ventricular (LV) function from contrast-enhanced images. We tested the feasibility of evaluating regional LV function by using power modulation imaging. In protocol 1, 9 anesthetized closed-chest pigs were studied. Images were obtained during contrast infusion at baseline, during LAD occlusion and reperfusion. In protocol 2, images were obtained in 20 patients (14 wall-motion abnormalities; 6 controls) during contrast enhancement. Off-line, frame-by-frame, semiautomated endocardial border detection was followed by color encoding of endocardial motion, followed by segmentation and calculation of regional fractional area changes. In all animals, coronary occlusions resulted in hypokinesis and decreased fractional area changes in LAD-related segments only, which were reversed during reperfusion. In patients, wall-motion analysis was in agreement with an expert reader of dynamic images in 92.5% segments, with interobserver variability of 12.5%. Color encoding of endocardial motion from contrast-enhanced power modulation images allows accurate quantitative assessment of regional LV function.

Multicenter Experience Using a New Prototype Transnasal Transesophageal Echocardiography Probe.

Transesophageal echocardiography (TEE) is an invaluable diagnostic tool, particularly in patients with inadequate transthoracic echocardiographic examinations. In addition, continuous TEE has been used to monitor ventricular and valvular performance in the intensive care unit and the operating room. However, current generation transesophageal probes have limitations in the critical care setting due to their size. Recently, a prototype miniaturized transesophageal probe was developed to overcome these limitations. This probe was used by five medical centers for 194 examinations. A large proportion of these patients were in the intensive care unit (43%), as well as mechanically ventilated (39%). Seventy percent (70%) of the subjects in this study were intubated nasally with the prototype probe, with a success rate of 88.5%. Oral intubation was successful in every case. Subject tolerance was good, and 25% of the patients were intubated for > 1 h. Nasal intubation with the probe was more likely in intensive care patients, ventilated subjects, and patients who were intubated for > 1 hour. TEE with this miniaturized probe is feasible and safe even in multi-instrumented critical care patients. This probe provides adequate diagnostic imaging capabilities and may allow imaging over prolonged periods of time, making it suitable for the serial monitoring of ventricular performance.

Color Kinesis: Principles of Operation and Technical Guidelines.

Color kinesis is a new echocardiographic technique that aids in the assessment of global and regional left ventricular performance during either systole or diastole. Color kinesis uses automated border detection technology based on backscatter data to display both the magnitude and timing of endocardial motion in real time. The color kinesis display superimposes a color overlay on the two-dimensional echocardiographic image; the number of color pixels represents the magnitude of endocardial motion, while the different colors represent the timing of endocardial motion according to a predefined color scheme. Because color kinesis is an operator-dependent technique, the steps involved in performing a technically adequate study will be reviewed as well as the pitfalls and technical limitations. The potential clinical applications of color kinesis will also be discussed.