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Objectives The goal of this study was to use machine learning to more accurately predict survival after echocardiography. Background Predicting patient outcomes (e.g., survival) following echocardiography is primarily based on ejection fraction (EF) and comorbidities. However, there may be significant predictive information within additional echocardiography-derived measurements combined with clinical electronic health record data. Methods Mortality was studied in 171,510 unselected patients who underwent 331,317 echocardiograms in a large regional health system. We investigated the predictive performance of nonlinear machine learning models compared with that of linear logistic regression models using 3 different inputs: 1) clinical variables, including 90 cardiovascular-relevant International Classification of Diseases, Tenth Revision, codes, and age, sex, height, weight, heart rate, blood pressures, low-density lipoprotein, high-density lipoprotein, and smoking; 2) clinical variables plus physician-reported EF; and 3) clinical variables and EF, plus 57 additional echocardiographic measurements. Missing data were imputed with a multivariate imputation by using a chained equations algorithm (MICE). We compared models versus each other and baseline clinical scoring systems by using a mean area under the curve (AUC) over 10 cross-validation folds and across 10 survival durations (6 to 60 months). Results Machine learning models achieved significantly higher prediction accuracy (all AUC >0.82) over common clinical risk scores (AUC = 0.61 to 0.79), with the nonlinear random forest models outperforming logistic regression (p Conclusions Machine learning can fully utilize large combinations of disparate input variables to predict survival after echocardiography with superior accuracy.

Introduction: An intriguing U-shape relationship between left ventricular ejection fraction (LVEF) and survival has recently been reported, with LVEFs of 60-65% associated with the lowest mortality risk. In heart failure, LVEF recovery has been linked to improved outcomes; however, the relationship between changes in LVEF (ΔLVEF) and survival in a general clinical population has not been studied. We hypothesized that ΔLVEF would have a non-linear relationship with all-cause mortality. Methods: A total of 194,599 echocardiograms from 57,823 patients with physician-reported LVEF were identified from Geisinger health records, along with dates of death or last living encounter, age, sex, smoking status, height, weight, and active diagnoses. ΔLVEF for a given echocardiogram was calculated for 136,776 studies as the difference between the most recent previous and current LVEF. Cox Proportional Hazards Regression was used to relate interaction between ΔLVEF and current LVEF to all-cause mortality while adjusting for confounders. Results: Death occurred in 15,419 patients who underwent 39,562 (29%) echocardiograms. Median follow up duration was 3.6 years (IQR, 1.3-7.2), and median time between tests was 1.0 year (IQR, 0.2-2.3). The interaction between LVEF and ΔLVEF ( P < 0.001) demonstrated that a stable LVEF of 60-65% was associated with the best survival (Figure). A decreased LVEF was universally associated with increased mortality, while LVEFs that had increased showed non-linear interactions. In general, an LVEF of 35-55% that had increased from the previous test was associated with a similar or slightly lower mortality than the same LVEF that was unchanged or had decreased, while an LVEF >55% that had increased was associated with an increase in mortality risk compared to those with a stable LVEF. Conclusions: Changes in LVEF have a non-linear relationship with all-cause mortality. In general, a constant, stable LVEF associates with the lowest risk of mortality.

Machine learning promises to assist physicians with predictions of mortality and of other future clinical events by learning complex patterns from historical data, such as longitudinal electronic health records. Here we show that a convolutional neural network trained on raw pixel data in 812,278 echocardiographic videos from 34,362 individuals provides superior predictions of one-year all-cause mortality. The model’s predictions outperformed the widely used pooled cohort equations, the Seattle Heart Failure score (measured in an independent dataset of 2,404 patients with heart failure who underwent 3,384 echocardiograms), and a machine learning model involving 58 human-derived variables from echocardiograms and 100 clinical variables derived from electronic health records. We also show that cardiologists assisted by the model substantially improved the sensitivity of their predictions of one-year all-cause mortality by 13% while maintaining prediction specificity. Large unstructured datasets may enable deep learning to improve a wide range of clinical prediction models. A deep learning model trained on raw pixel data in hundreds of thousands of echocardiographic videos for the prediction of one-year all-cause mortality outperforms clinical scores and improves predictions by cardiologists.

Aims We investigated the relationship between clinically assessed left ventricular ejection fraction (LVEF) and survival in a large, heterogeneous clinical cohort. Methods and results Physician-reported LVEF on 403 977 echocardiograms from 203 135 patients were linked to all-cause mortality using electronic health records (1998–2018) from US regional healthcare system. Cox proportional hazards regression was used for analyses while adjusting for many patient characteristics including age, sex, and relevant comorbidities. A dataset including 45 531 echocardiograms and 35 976 patients from New Zealand was used to provide independent validation of analyses. During follow-up of the US cohort, 46 258 (23%) patients who had undergone 108 578 (27%) echocardiograms died. Overall, adjusted hazard ratios (HR) for mortality showed a u-shaped relationship for LVEF with a nadir of risk at an LVEF of 60–65%, a HR of 1.71 [95% confidence interval (CI) 1.64–1.77] when ≥70% and a HR of 1.73 (95% CI 1.66–1.80) at LVEF of 35–40%. Similar relationships with a nadir at 60–65% were observed in the validation dataset as well as for each age group and both sexes. The results were similar after further adjustments for conditions associated with an elevated LVEF, including mitral regurgitation, increased wall thickness, and anaemia and when restricted to patients reported to have heart failure at the time of the echocardiogram. Conclusion Deviation of LVEF from 60% to 65% is associated with poorer survival regardless of age, sex, or other relevant comorbidities such as heart failure. These results may herald the recognition of a new phenotype characterized by supra-normal LVEF.

PURPOSE To determine the optimal respiratory navigator gating configuration for the quantification of left ventricular strain using spiral cine displacement encoding with stimulated echoes (DENSE) MRI. MATERIALS AND METHODS Two-dimensional spiral cine DENSE was performed on a 3 Tesla MRI using two single-navigator configurations (retrospective, prospective) and a combined "dual-navigator" configuration in 10 healthy adults and 20 healthy children. The adults also underwent breathhold DENSE as a reference standard for comparisons. Peak left ventricular strains, signal-to-noise ratio (SNR), and navigator efficiency were compared. Subjects also underwent dual-navigator gating with and without visual feedback to determine the effect on navigator efficiency. RESULTS There were no differences in circumferential, radial, and longitudinal strains between navigator-gated and breathhold DENSE (P = 0.09-0.95) (as confidence intervals, retrospective: [-1.0%-1.1%], [-7.4%-2.0%], [-1.0%-1.2%]; prospective: [-0.6%-2.7%], [-2.8%-8.3%], [-0.3%-2.9%]; dual: [-1.6%-0.5%], [-8.3%-3.2%], [-0.8%-1.9%], respectively). The dual configuration maintained SNR compared with breathhold acquisitions (16 versus 18, P = 0.06). SNR for the prospective configuration was lower than for the dual navigator in adults (P = 0.004) and children (P

Introduction Displacement encoding with stimulated echoes (DENSE) is a phase contrast technique that encodes tissue displacement into phase images, which are typically processed into measures of cardiac function such as strains. For improved signal to noise ratio and spatiotemporal resolution, DENSE is often acquired with a spiral readout using an 11.1 ms readout duration. However, long spiral readout durations are prone to blurring due to common phenomena such as off-resonance and T2* decay, which may alter the resulting quantifications of strain. We hypothesized that longer readout durations would reduce image quality and underestimate cardiac strains at both 3.0 T and 1.5 T and that using short readout durations could overcome these limitations. Material and methods Computational simulations were performed to investigate the relationship between off-resonance and T2* decay, the spiral cine DENSE readout duration, and measured radial and circumferential strain. Five healthy participants subsequently underwent 2D spiral cine DENSE at both 3.0 T and 1.5 T with several different readout durations 11.1 ms and shorter. Pearson correlations were used to assess the relationship between cardiac strains and the spiral readout duration. Results Simulations demonstrated that long readout durations combined with off-resonance and T2* decay yield blurred images and underestimate strains. With the typical 11.1 ms DENSE readout, blurring was present in the anterior and lateral left ventricular segments of participants and was markedly improved with shorter readout durations. Radial and circumferential strains from those segments were significantly correlated with the readout duration. Compared to the 1.9 ms readout, the 11.1 ms readout underestimated radial and circumferential strains in those segments at both field strengths by up to 19.6% and 1.5% (absolute), or 42% and 7% (relative), respectively. Conclusions Blurring is present in spiral cine DENSE images acquired at both 3.0 T and 1.5 T using the typical 11.1 ms readout duration, which yielded substantially reduced radial strains and mildly reduced circumferential strains. Clinical studies using spiral cine DENSE should consider these limitations, while future technical advances may need to leverage accelerated techniques to improve the robustness and accuracy of the DENSE acquisition rather than focusing solely on reduced acquisition time.

Approximately 20% of students experience reading failure each year. One of the difficulties associated with this large percentage is that it has been documented that pre-service teachers may not be receiving the most appropriate training regarding reading acquisition. The present study sought to determine if pre-service teachers were proficient in phonological processing skills and thus capable of learning concepts for which these skills are prerequisite. One-hundred sixty-four participants (85 pre-service teachers and 79 non-education majors) were administered the Comprehensive Test of Phonological Processing (CTOPP). The results indicated that pre-service teachers’ phonological processing skills were sufficiently developed and not significantly different from non-education majors or from the CTOPP's normative sample. These students have the ability to learn the concepts related to the science of reading. Components of an appropriate curriculum for pre-service teachers such that they can acquire this kno...

Aims Previous studies using regression analyses have failed to identify which patients with repaired tetralogy of Fallot (rTOF) are at risk for deterioration in ventricular size and function despite using common clinical and cardiac function parameters as well as cardiac mechanics (strain and dyssynchrony). This study used a machine learning pipeline to comprehensively investigate the predictive value of the baseline variables derived from cardiac magnetic resonance (CMR) imaging and provide models for identifying patients at risk for deterioration. Methods and results Longitudinal deterioration for 153 patients with rTOF was categorized as 'none', 'minor', or 'major' based on changes in ventricular size and ejection fraction between two CMR scans at least 6 months apart (median 2.7 years). Baseline variables were measured at the time of the first CMR. An exhaustive variable search with a support vector machine classifier and five-fold cross-validation was used to predict deterioration and identify the most useful variables. For predicting any deterioration (minor or major) vs. no deterioration, the mean area under the curve (AUC) was 0.82 ± 0.06. For predicting major deterioration vs. minor or no deterioration, the AUC was 0.77 ± 0.07. Baseline left ventricular (LV) ejection fraction, LV circumferential strain, and pulmonary regurgitation were most useful for achieving accurate predictions. Conclusion For the prediction of deterioration in patients with rTOF, a machine learning pipeline uncovered the utility of baseline variables that was previously lost to regression analyses. The predictive models may be useful for planning early interventions in patients with high risk.

Background Left ventricular (LV) torsion is an important indicator of cardiac function that is limited by high inter-test variability (50% of the mean value). We hypothesized that this high inter-test variability is partly due to inconsistent breath-hold positions during serial image acquisitions, which could be significantly improved by using a respiratory navigator for cardiovascular magnetic resonance (CMR) based quantification of LV torsion. Methods We assessed respiratory-related variability in measured LV torsion with two distinct experimental protocols. First, 17 volunteers were recruited for CMR with cine displacement encoding with stimulated echoes (DENSE) in which a respiratory navigator was used to measure and then enforce variability in end-expiratory position between all LV basal and apical acquisitions. From these data, we quantified the inter-test variability of torsion in the absence and presence of enforced end-expiratory position variability, which established an upper bound for the expected torsion variability. For the second experiment (in 20 new, healthy volunteers), 10 pairs of cine DENSE basal and apical images were each acquired from consecutive breath-holds and consecutive navigator-gated scans (with a single acceptance position). Inter-test variability of torsion was compared between the breath-hold and navigator-gated scans to quantify the variability due to natural breath-hold variation. To demonstrate the importance of these variability reductions, we quantified the reduction in sample size required to detect a clinically meaningful change in LV torsion with the use of a respiratory navigator. Results The mean torsion was 3.4 ± 0.2°/cm. From the first experiment, enforced variability in end-expiratory position translated to considerable variability in measured torsion (0.56 ± 0.34°/cm), whereas inter-test variability with consistent end-expiratory position was 57% lower (0.24 ± 0.16°/cm, p

Mechanics of the left ventricle (LV) are important indicators of cardiac function. The role of right ventricular (RV) mechanics is largely unknown due to the technical limitations of imaging its thin wall and complex geometry and motion. By combining 3D Displacement Encoding with Stimulated Echoes (DENSE) with a post-processing pipeline that includes a local coordinate system, it is possible to quantify RV strain, torsion, and synchrony. In this study, we sought to characterize RV mechanics in 50 healthy individuals and compare these values to their LV counterparts. For each cardiac frame, 3D displacements were fit to continuous and differentiable radial basis functions, allowing for the computation of the 3D Cartesian Lagrangian strain tensor at any myocardial point. The geometry of the RV was extracted via a surface fit to manually delineated endocardial contours. Throughout the RV, a local coordinate system was used to transform from a Cartesian strain tensor to a polar strain tensor. It was then possible to compute peak RV torsion as well as peak longitudinal and circumferential strain. A comparable analysis was performed for the LV. Dyssynchrony was computed from the standard deviation of regional activation times. Global circumferential strain was comparable between the RV and LV (−18.0% for both) while longitudinal strain was greater in the RV (−18.1% vs. −15.7%). RV torsion was comparable to LV torsion (6.2 vs. 7.1 degrees, respectively). Regional activation times indicated that the RV contracted later but more synchronously than the LV. 3D spiral cine DENSE combined with a post–processing pipeline that includes a local coordinate system can resolve both the complex geometry and 3D motion of the RV.

Rat models have assumed an increasingly important role in cardiac research. However, a detailed profile of regional cardiac mechanics, such as strains and torsion, is lacking for rats. We hypothesized that healthy rat left ventricles (LVs) exhibit regional differences in cardiac mechanics, which are part of normal function. In this study, images of the LV were obtained with 3D cine displacement encoding with stimulated echoes (DENSE) cardiovascular magnetic resonance in 10 healthy rats. To evaluate regional cardiac mechanics, the LV was divided into basal, mid-ventricular, and apical regions. The myocardium at the mid-LV was further partitioned into four wall segments (i.e. septal, inferior, lateral, and anterior) and three transmural layers (i.e. sub-endocardium, mid-myocardium, and sub-epicardium). The six Lagrangian strain components (i.e. Err , Ecc , Ell , Ecl , Erl , and Ecr ) were computed from the 3D displacement field and averaged within each region of interest. Torsion was quantified using the circumferential-longitudinal shear angle. While peak systolic Ecl differed between the mid-ventricle and apex, the other five components of peak systolic strain were similar across the base, mid-ventricle, and apex. In the mid-LV myocardium, Ecc decreased gradually from the sub-endocardial to the sub-epicardial layer. Ell demonstrated significant differences between the four wall segments, with the largest magnitude in the inferior segment. Err was uniform among the four wall segments. Ecl varied along the transmural direction and among wall segments, whereas Erl differed only among the wall segments. Erc was not associated with significant variations. Torsion also varied along the transmural direction and among wall segments. These results provide fundamental insights into the regional contractile function of healthy rat hearts, and form the foundation for future studies on regional changes induced by disease or treatments.

To determine the optimal respiratory navigator gating configuration for the quantification of left ventricular strain using spiral cine displacement encoding with stimulated echoes (DENSE) MRI.Two-dimensional spiral cine DENSE was performed on a 3 Tesla MRI using two single-navigator configurations (retrospective, prospective) and a combined "dual-navigator" configuration in 10 healthy adults and 20 healthy children. The adults also underwent breathhold DENSE as a reference standard for comparisons. Peak left ventricular strains, signal-to-noise ratio (SNR), and navigator efficiency were compared. Subjects also underwent dual-navigator gating with and without visual feedback to determine the effect on navigator efficiency.There were no differences in circumferential, radial, and longitudinal strains between navigator-gated and breathhold DENSE (P = 0.09-0.95) (as confidence intervals, retrospective: [-1.0%-1.1%], [-7.4%-2.0%], [-1.0%-1.2%]; prospective: [-0.6%-2.7%], [-2.8%-8.3%], [-0.3%-2.9%]; dual: [-1.6%-0.5%], [-8.3%-3.2%], [-0.8%-1.9%], respectively). The dual configuration maintained SNR compared with breathhold acquisitions (16 versus 18, P = 0.06). SNR for the prospective configuration was lower than for the dual navigator in adults (P = 0.004) and children (P 0.001). Navigator efficiency was higher (P 0.001) for both retrospective (54%) and prospective (56%) configurations compared with the dual configuration (35%). Visual feedback improved the dual configuration navigator efficiency to 55% (P 0.001).When quantifying left ventricular strains using spiral cine DENSE MRI, a dual navigator configuration results in the highest SNR in adults and children. In adults, a retrospective configuration has good navigator efficiency without a substantial drop in SNR. Prospective gating should be avoided because it has the lowest SNR. Visual feedback represents an effective option to maintain navigator efficiency while using a dual navigator configuration.2 J. Magn. Reson. Imaging 2017;45:786-794.

Background Obesity affects nearly one in five children and is associated with increased risk of premature death. Obesity-related heart disease contributes to premature death. We aimed to use cardiovascular magnetic resonance (CMR) to comprehensively characterize the changes in cardiac geometry and function in obese children. Methods and results Forty-one obese/overweight (age 12 ± 3 years, 56 % female) and 29 healthy weight children (age 14 ± 3 years, 41 % female) underwent CMR, including both standard cine imaging and displacement encoded imaging, for a complete assessment of left ventricular (LV) structure and function. After adjusting for age, LV mass index was 23 % greater (27 ± 4 g/m2.7 vs 22 ± 3 g/m2.7, p

The eigenmodes of a non-viscous, compressible liquid drop are investigated. The spectrum is shown to be derivable from two Hermitian eigenvalue problems which are weakly coupled by a non-Hermitian operator. It is shown that both eigenvalue problems admit an asymptotic, lepto-dermous expansion. Their contribution to the entropy of the droplet therefore also allows for such an expansion.

Background Advanced cardiac magnetic resonance (CMR) acquisitions often require long scan durations that necessitate respiratory navigator gating. This is particularly important in children with limited ability to hold their breath. We hypothesized that visual feedback of diaphragm position using an interactive videogame during CMR would increase navigator efficiency and improve image quality in children.

Background Displacement Encoding with Stimulated Echoes (DENSE) encodes displacement into the phase of the magnetic resonance signal. The encoding frequency (ke) maps the measured phase to tissue displacement while the strength of the encoding gradients affects image quality. 2D cine DENSE studies have used a ke of 0.10 cycles/mm, which is high enough to remove an artifact-generating echo from k-space, provide high sensitivity to tissue displacements, and dephase the blood pool. However, through-plane dephasing can remove the unwanted echo and dephase the blood pool without relying on high ke. Additionally, the high sensitivity comes with the costs of increased phase wrapping and intra-voxel dephasing. We hypothesized that ke below 0.10 cycles/mm can be used to improve image characteristics and provide accurate measures of cardiac mechanics. Methods Spiral cine DENSE images were obtained for 10 healthy subjects and 10 patients with a history of heart disease on a 3 T Siemens Trio. A mid-ventricular short-axis image was acquired with different ke: 0.02, 0.04, 0.06, 0.08, and 0.10 cycles/mm. Peak twist, circumferential strain, and radial strain were compared between acquisitions employing different ke using Bland-Altman analyses and coefficients of variation. The percentage of wrapped pixels in the phase images at end-systole was calculated for each ke. The dephasing of the blood signal and signal to noise ratio (SNR) were also calculated and compared. Results Negligible differences were seen in strains and twist for all ke between 0.04 and 0.10 cycles/mm. These differences were of the same magnitude as inter-test differences. Specifically, the acquisitions with 0.04 cycles/mm accurately quantified cardiac mechanics and had zero phase wrapping. Compared to 0.10 cycles/mm, the acquisitions with 0.04 cycles/mm had 9 % greater SNR and negligible differences in blood pool dephasing. Conclusions For 2D cine DENSE with through-plane dephasing, the encoding frequency can be lowered to 0.04 cycles/mm without compromising the quantification of twist or strain. The amount of wrapping can be reduced with this lower value to greatly simplify the input to unwrapping algorithms. The strain and twist results from studies using different encoding frequencies can be directly compared.

Background Obesity affects one in five children in the US and these children tend to maintain excess weight into adulthood. It has recently been shown that childhood obesity is associated with both cardiac remodeling (hypertrophy) and contractile dysfunction. However, the etiology of these cardiac changes is not well understood. We hypothesized that cardiac remodeling and dysfunction could not be entirely explained by elevations in blood pressure and that excess abdominal and epicardial adiposity may also correlate with cardiac changes.

Physics in medicine and biology 60(6), 2231-2255 (2015). doi:10.1088/0031-9155/60/6/2231, Published by IOP Publ., Bristol

Generation of Chinese Hamster Ovary (CHO) cell lines stably expressing green fluorescent protein (GFP) was achieved using a plasmid vector that encoded the red-shifted pCX-xGFP under the control of a strong hybrid promoter composed of a CMV enhancer and a β-actin/β-globin gene promoter. Cotransfection of the promoter-less pSV2-Neo helper plasmid transmitting neomycin resistance was followed by selection with the antibiotic G418. Constitutive GFP expression could be visualized in living and fixed cells using fluorescence spectroscopy, fluorescence microscopy, and flow cytometry. DNA repair-proficient (AA8) and deficient (UV5) CHO strains were used for survival tests after UVC irradiation. Cells carrying the GFP construct (AA8-pGFP, UV5-pGFP) show the same response to UV irradiation (colony forming ability) as their nontransformed parental cell lines (AA8, UV5). Using GFP as a marker for cell viability, cells were harvested after certain postirradiation growth periods and the numbers of GFP expressing cells and fluorescence intensities were determined by FACS analysis. Generally, GFP fluorescence in irradiated cells is not seen when cell membranes are damaged (leak-out of the soluble GFP). Irradiated cells without membrane damage express GFP continuously (leading to a dose-dependent increase in GFP contents).

Because of the importance of such factors as appearance and vigor in turf management, genetic selection of Kentucky bluegrass (Poa pratensis L.) is often conducted at high levels of N application. This process can mask potential differences between genotypes in N effidency, especially under low N levels. The case is also made that because soil is the medium in which plant selections ultimately must perform, cultivar screening for N efficiency in solution culture should relate to results in soil. This study was conducted to evaluate N-utilization efficiency (NUE-mg plant dry matter mg -1 plant N) in six bluegrass cultivars at low (0.2, 0.7 mM NO 3 -N) and high (3.5 mM NO 3 -N) levels of N supply in nutrient solution culture (nutriculture) and soil. With high N supply, total plant N accumulation and N-root uptake effidency (NRE-mg plant N g -1 root dry matter) increased in each cultivar, while NUE and shoot elfidency ratio (SER-mg shoot dry matter mg -1 shoot N) decreased, with the magnitude and relative response dependent on genotype and medium. As a group, as well as individually, cultivars Asset, Dawn, and Trenton were higher yielding, more responsive to increasing solution N concentration, and more efficient (NUE) at low levels of N supply than cultivars Limousine, Barzan, or Midnight. Under low N supply, NUE in nutriculture ranged from 26.2 (g plant dry weight mg -1 N) in Limousine to 40.1 in Asset, and in soil from 63.6 in Midnight to 77A in Asset. Differences in NUE among cultivars were more assodated with shoot efficiency than with root absorption efficiency. Despite noticeably higher NUE in soil than in nutriculture, and significant effects of N fertility, genotypic differences in the various N efficiency traits in solution culture were also apparent in soil. The results suggest that NUE in Kentucky bluegrass can be enhanced by cultivar selection under low-N conditions. While the similarities of the actual N conditions between nutriculture and soil remain in question, it appears that solution culture can be used as an effective surrogate for characterizing NUE in divergent types of bluegrass cultivars.

The determination of fission barrier heights of charged clusters of alkali atoms requires the calculation of the electrostatic self-energy of arbitrarily shaped, conducting droplets. For axially symmetric shapes we propose to determine a charge distribution on the axis giving rise to the same electric field outside the droplet as the actual surface charge. This leads to an ill-posed inversion problem. We discuss its regularization and demonstrate the usefulness of the method in some examples.

An essential component of an introductory turfgrass manage­ ment course is the description of how turfgrass species are adapt­ ed to different cultural systems and environments. The objectives of this project were to develop an interactive pro­ gram to introduce the characteristics of turfgrass species and their optimum environments and to evaluate the students' gain in understanding turf species characteristics through this ap­ proach. A self-contained application, Turf Species, was con­ structed using the SuperCard development tool. Turf Species consists of three sections including a self-paced tour of the spe­ cies, a what if establishment section, and randomly composed reinforcement quizzes with automatic grading. Turf Species was designed to be distributed to students on diskette for self-paced study and reinforcement of material presented during previous lectures. Each student who used the Turf Species tool spent ap­ proximately 2 h evaluating the program. Seventy-one percent of the student evaluators felt that the graphic representations or illustrations for each species aided in their understanding of the material. All of the evaluators indicated that the testing mod­ ule helped in their understanding of the turf species, and 86010 of them suggested that the Turf Species program should be used more extensively in the introductory turfgrass management course. An evaluation of the test scores found on returned dis­ kettes showed an average examination grade of 52% with a range from 5 to 100%.

Spores of different strains of Bacillus subtilis and the Escherichia coli plasmid pUC19 were exposed to selected conditions of space (space vacuum and/or defined wavebands and intensities of solar ultraviolet radiation) in the experiment ER 161 "Exobiological Unit" of the Exobiology Radiation Assembly (ERA) on board of the European Retrievable Carrier (EURECA). After the approximately 11 months lasting mission, their responses were studied in terms of survival, mutagenesis in the his (B. subtilis) or lac locus (pUC19), induction of DNA strand breaks, efficiency of DNA repair systems, and the role of external protective agents. The data were compared with those of a simultaneously running ground control experiment. The survival of spores treated with the vacuum of space, however shielded against solar radiation, is substantially increased, if they are exposed in multilayers and/or in the presence of glucose as protective, whereas all spores in "artificial meteorites", i.e. embedded in clays or simulated Martian soil, are killed. Vacuum treatment leads to an increase of mutation frequency in spores, but not in plasmid DNA. Extraterrestrial solar ultraviolet radiation is mutagenic, induces strand breaks in the DNA and reduces survival substantially; however, even at the highest fluences, i.e. 3 x 10(8) J m-2, a small but significant fraction of spores survives the insolation. Action spectroscopy confirms results of previous space experiments of a synergistic action of space vacuum and solar UV radiation with DNA being the critical target.

Estimation of the lower limit of the canopy-air temperature differential, (T c -T a ) LL , is required for calculation of an empirically-based crop water stress, index. This research determined the complexity of model needed for accurate estimation of (T c -T a ) LL for several field grown cultivars of Kentucky bluegrass (Poa pratensis L.) and for creeping bentgrass (Agrostis stolonifera L. var. palustris (Huds.) Farw.). Regression models using vapor pressure deficit of the air (VPD), net radiation load (R n ), and wind speed (WS) were developed for predicting (T c -T a ) LL

Writing in horticulture courses helps students develop a better understanding of the subject matter and prepares them for careers where they must communicate with the general public. Three writing assignments that can be modified for use in a wide range of horticulture courses are presented, along with grading sheets. The writing assignments simulate situations that horticulturists encounter frequently; i.e., answering questions about plant materials and their utilization and maintenance or proposing site improvements or additional expenditures for maintenance programs.

We examine the predictive ability of habitat-species relationship models in island semi-desert environmentsusing as model species the Canary Islands stonechat (Saxicola dacotiae), an endemic birdinhabiting the arid island of Fuerteventura.We investigated nest site selection and the effects of land useon its distribution in a multi-scale approach using nest positions obtained during three consecutivebreeding seasons. We identified two environmental predictors, namely Tasseled cap 1 (a range value ofland brightness) and slope, and three variables derived from human use (house densities, unpaved roadsand fences) as the best predictors of occurrence of the species. Only slope had a positive and significanteffect on stonechat occurrence; the rest being negative. Results were not restricted by the scale, indicatingthat design of special protection areas should be developed considering the landscape scale. Ourresults provide a robust prediction of the species distribution throughout Fuerteventura, demonstratingthat our approach can also cope for the low vegetation signal within small arid regions such as islands.Future land use planning and management for the island should avoid the presence of negative impactelements such as opening new roads and new urbanisations in nearby habitats with the highest probabilitiesof species occurrence. We examine the predictive ability of habitat-species relationship models in island semi-desert environments using as model species the Canary Islands stonechat (Saxicola dacotiae), an endemic bird inhabiting the arid island of Fuerteventura. We investigated nest site selection and the effects of land use on its distribution in a multi-scale approach using nest positions obtained during three consecutive breeding seasons. We identified two environmental predictors, namely Tasseled cap 1 (a range value of land brightness) and slope, and three variables derived from human use (house densities, unpaved roads and fences) as the best predictors of occurrence of the species. Only slope had a positive and significant effect on stonechat occurrence; the rest being negative. Results were not restricted by the scale, indicating that design of special protection areas should be developed considering the landscape scale. Our results provide a robust prediction of the species distribution throughout Fuerteventura, demonstrating that our approach can also cope for the low vegetation signal within small arid regions such as islands. Future land use planning and management for the island should avoid the presence of negative impact elements such as opening new roads and new urbanisations in nearby habitats with the highest probabilities of species occurrence.

Um die biochemisch erfasbare genetische Variabilitat von Damwild (Dama dama) in Revieren in Nordrhein-Westfalen zu ermitteln, wurden bei insgesamt 56 Individuen sechs Isoenzymsysteme aus Lebergewebe gelelektrophoretisch analysiert. Von den erfasten 11 Genorten waren 8 monomorph. Die durchschnittliche Heterozygotierate aller Populationen betrug 1,4 %, die durchschnittliche Anzahl Allele pro Genort 1,37. Es fanden sich keine signifikanten Unterschiede zwischen den Populationen. Masnahmen zur jagdlichen Bewirtschaftung des Damwildes werden diskutiert.

Um die biochemisch erfasbare genetische Variabilitat von Rehen (Capreolus capreolus) aus funf Untersuchungsrevieren des Rheinlandes zu ermitteln, wurden bei insgesamt 71 Individuen sieben Isoenzymsysteme aus Lebergewebe mittels Gelelektrophorese untersucht. Von den erfasten 14 Genloci waren neun mono- und funf polymorph. Die durchschnittliche Heterozygotierate fur alle funf Populationen betrug 4,92 %. Die durchschnittliche Anzahl Allele pro Genlocus 1,5. Es fanden sich jedoch deutliche Unterschiede zwischen den einzelnen Populationen. So zeigte ein seit uber 60 Jahren isolierter Rehbestand im Vergleich mit Kontrollpopulationen eine deutliche Abnahme der genetischen Variabilitat. Die zugrundeliegenden Ursachen werden diskutiert.

Iron applications are sometimes used to enhance the color (darker green) of turfgrass stands even when iron is not deficient. A study was conducted to determine the feasibility of replacing a portion of the total yearly N applied to Kentucky bluegrass (Poa pratensis L.) with iron. Turfgrass response to iron chelate (Sequestrene 330) applications at 2.2 kg Fe ha‐1 in combination with three liquid‐applied N sources (urea, Formolene, and FLUF) at 25 kg N ha‐1 was compared to turf response from applications of the N sources at 49 kg N ha‐l. Iron was substituted for part of the N in either the first and second, second and third, or third application in a four application per year program. The study was conducted for three years, and the fertilized turf was rated for color weekly during the growing season. Depending on N source and frequency of Fe application, turf treated with N received higher color ratings compared to turf receiving Fe + N on 13 (Formolene + Fe in third application) to 36% (Fluf + F...

Acute cerebral ischemia resulting from the occlusion of a large or medium size intracranial artery is a known complication of antiphospholipid antibody syndrome (AAS). Usually these patients are treated by low dose aspirin and anticoagulants to prevent a stroke. We are reporting a case of acute stroke in a patient with AAS in whom combined intravenous and intraarterial thrombolytics were used emergently with an excellent outcome. A 32-year-old woman presented with a left hemispheric stroke of 2.5 hours duration. A computed tomography (CT) study of the brain was normal. The patient was treated with intravenous tissue plasminogen activator but remained aphasic and hemiplegic. Subsequently, the patient had a stable xenon CT cerebral blood flow study demonstrating low flow in the left middle cerebral artery (MCA) territory and an angiogram, which demonstrated occlusion of the left MCA. The patient was then treated with intraarterial urokinase with a rapid and marked improvement in her neurological deficit. The case suggests that stroke patients can be treated safely and effectively with combined thrombolytics.

We confirm the fission-barrier heights for surface-charged droplets obtained in earlier work within a very differently defined shape class. In addition we show that the Rayleigh-Taylor instability which occurs for spherical droplets for fissilities x > 1 is already seen for x = 0.9 in spheroids with sufficiently large eccentricity. We finally present an analytic formula for the electrostatic energy of two touching, surface-charged, conducting droplets.

Background Displacement Encoding with Stimulated Echoes (DENSE) directly measures tissue displacements and can be used to quantify cardiac mechanics. Multi-dimensional DENSE results in lengthy scans that require respiratory gating, acquiring data only while the diaphragm is within a prespecified “acceptance window.” Because it is not possible to perform respiratory gating during data acquisition, DENSE can employ the following respiratory gating strategies: 1) acquire data and keep it if the diaphragm is inside the window after acquisition (retrospective) 2) acquire data and keep it only if the diaphragm was inside the window right before data acquisition (prospective) or 3) a combination of retrospective and prospective where the diaphragm must be inside the window both before and after data acquisition (combined) (Fig 1). Combined respiratory gating is not used often because more data is discarded, resulting in longer scan times. It is possible, however, that with only retrospective or prospective respiratory gating, the diaphragm may not be within the acceptance window for the entirety of data acquisition (i.e. drifting into or out of the window), negatively affecting image quality. We hypothesized that the combined respiratory gating would result in significantly different estimates of left ventricular strains compared to either retrospective or prospective respiratory gating.

Background Cardiac magnetic resonance (CMR) can be used to quantify cardiac mechanics from images that are generally acquired during an end-expiratory breath-hold. Unfortunately, it is difficult for subjects to hold their breath at the exact same position when undergoing a series of breath-holds during a typical CMR study. The effect of patient-specific variability in breath-hold positions on measures of cardiac mechanics has not been investigated. We hypothesized that normal variability in breath-hold positions would significantly affect estimates of left ventricular strains and torsion.

Spores of Bacillus subtilis were exposed to space in the BIOPAN facility of the European Space Agency onboard of the Russian Earth-orbiting FOTON satellite. The spores were exposed either in dry layers without any protecting agent, or mixed with clay, red sandstone, Martian analogue soil or meteorite powder, in dry layers as well as in so-called 'artificial meteorites', i.e. cubes filled with clay and spores in naturally occurring concentrations. After about 2 weeks in space, their survival was tested from the number of colony formers. Unprotected spores in layers open to space or behind a quartz window were completely or nearly completely inactivated (survival rates in most casesor = 10(-6)). The same low survival was obtained behind a thin layer of clay acting as an optical filter. The survival rate was increased by 5 orders of magnitude and more, if the spores in the dry layer were directly mixed with powder of clay, rock or meteorites, and up to 100% survival was reached in soil mixtures with spores comparable to the natural soil to spore ratio. These data confirm the deleterious effects of extraterrestrial solar UV radiation. Thin layers of clay, rock or meteorite are only successful in UV-shielding, if they are in direct contact with the spores. The data suggest that in a scenario of interplanetary transfer of life, small rock ejecta of a few cm in diameter could be sufficiently large to protect bacterial spores against the intense insolation; however, micron-sized grains, as originally requested by Panspermia, may not provide sufficient protection for spores to survive. The data are also pertinent to search for life on Mars and planetary protection considerations for future missions to Mars.

Chronic skin colonization with Staphylococcus aureus is a characteristic feature of atopic eczema (AE), and about 60% of S. aureus strains isolated from the skin of patients with AE secrete enterotoxins. Furthermore, IgE antibodies to S. aureus enterotoxins have been identified in 78% of patients with AE.To examine the S. aureus enterotoxin-induced histamine and leukotriene release of basophils from patients with AE.Peripheral blood basophils from patients with AE were stimulated with the staphylococcal enterotoxins A, B, D, E and toxic shock syndrome toxin-1. Additionally, priming experiments were performed with interleukin (IL)-3, IL-8 and granulocyte/macrophage colony-stimulating factor followed by stimulation with S. aureus enterotoxins.In patients with AE, basophils secreted significantly higher amounts of histamine and leukotriene C4 (LTC4) than in healthy controls. The priming experiments showed additional histamine and LTC4 release in the group of AE patients.Histamine and leukotriene generation from atopic basophils stimulated with staphylococcal enterotoxins may indicate a role for these toxins as possible allergens in at least a subgroup of patients with AE.

Das Plattenepithelkarzinom der Haut und Unterlippe ist nach dem Basaliom der zweithaufigste maligne Hauttumor noch vor dem Melanom. Wahrend die beiden letztgenannten Tumoren in der Literatur einen breiten Raum einnehmen und insbesondere beim Melanom durch neuere multizentrische Studien das Wissen uber epidemiologische, biologische und therapeutische Faktoren verbreitert werden konnte, bleibt die Dignitat des Plattenepithelkarzinoms und seiner Varianten oftmals noch umstritten. Im Einzelfall ist oft nicht mit hinreichender Sicherheit klar, wie hoch das Metastasierungsrisiko einzustufen ist. Die bisher bekannt gewordenen Publikationen lassen aufgrund unterschiedlicher Kollektive keine Vergleiche zu. Auch Kollektive, denen die gultige TNM-Einteilung fur das Karzinom zugrunde gelegt worden war, zeigen diesen Mangel, da diese Einteilung durch ihr grobes Raster zu viele unterschiedliche Karzinome zusammenfast. Aus dieser Unsicherheit in der Einschatzung der Malignitat des Hautkarzinoms resultieren unterschiedlichste Therapieschemata von der einfachen knappen lokalen Behandlung uber radikale lokale Masnahmen mit nachfolgender prophylaktischer Therapie der regionaren Lymphknoten. Entsprechend uneinheitlich wird die Nachsorge von Plattenepithelkarzinomen betrieben. Wie beim Melanom orientiert sich diese zumeist an der Tumordicke als vermeintlich wichtigstem prognostischen Faktor.