Pacing for complete heart block in pregnancy

Whereas sinus tachycardia and paroxysmal supraventricular tachycardia are common during pregnancy, bradyarrhythmias are infrequent. Moreover, bradyarrhythmias are generally well tolerated during pregnancy. Nevertheless, a 12-lead ECG is indicated for pregnant women who present with bradycardia, to rule out sinoatrial (SA) node dysfunction or AV conduction abnormalities. Third-degree AV block (complete heart block, CHB) requires multidisciplinary care during pregnancy, with combined input from Cardiologists and Obstetricians. As CHB is associated with increased mortality and morbidity if left untreated, permanent pacing is usually indicated during pregnancy, even if the patient remains asymptomatic. However, not all pregnant patients with CHB require urgent pacing. In a pregnant patient who has CHB with an escape rhythm with narrow QRS complexes and rate of >50bpm, permanent pacemaker implantation can be delayed until after delivery, as described in this case report

Challenges of managing patients with mechanical heart valve thrombosis in pregnancy: A case series

Mechanical valve thrombosis is a feared complication in pregnant women with mechanical heart valves (MHV). It is associated with a high maternal and foetal morbidity and mortality. Optimal anticoagulation strategies for pregnant women with MHV remain controversial. Vitamin K antagonists (VKA) are the most effective treatment regimen to prevent valve thrombosis and are therefore considered the safest treatment for the mother. However, VKAs increase the risk of embryopathy, foetopathy, foetal haemorrhage and foetal loss. A particular challenge is to balance the need for adequate anticoagulation for MHV during pregnancy against the risk of bleeding, teratogenicity and fetotoxicity. In this case series, we describe complexity of the management of anticoagulation in pregnant patients with MHV, and describe 2 treatment approaches in patients with MHV thrombosis. Our case series high-lights that anticoagulation strategy should be individualised, and that best management is provided by a multidisciplinary cardio-obstetric team

Determinants of Spatial and Temporal Variation of West Nile Virus Transmission in Texas

West Nile virus (WNV) is a zoonotic vector-borne virus that infects avian and mammal hosts. In Texas, WNV was first reported in 2002 in Harris County and has since been reported annually throughout the state. With variable funding available for mosquito surveillance in Texas, predictive modeling is an economical method for mosquito control, but has not been parameterized for major metropolitan areas of central and southeast Texas. Thus, this dissertation uses historical databases to create predictive models that are specifically tailored for major cities in Texas. To investigate the 2012 WNV epidemic in Dallas County, TX, logistic regression models identified an index of urbanization (composed of greater population density, lower normalized difference vegetation index, higher coverage of urban land types, and more impervious surfaces), lower elevation, and older populations as key factors in predicting the risk of WNV in Culex quinquefasciatus. Our model was then extrapolated as a risk map, which highlighted north and central Dallas County as areas of high risk for WNV-positive mosquitoes. A similar study for Harris County was conducted, where the best-fit model found that areas with higher elevation, more impervious surfaces, greater median income, and predominantly Hispanic populations will have higher vector indexes, which measure the average number of WNV-infected female Culex mosquitoes collected per trap night. The predictive map based on this model emphasized high-risk areas in central and north Harris County. Harris County’s long-term database was also used to investigate temporal patterns between vector abundance, WNV infection in Cx. quinquefasciatus, and weather patterns. A time-series analysis revealed correlations between abundance and environmental variability measurements, following our hypothesis of Schmalhausen’s law that states organisms are susceptible to mean (average) temperature and precipitation measurements as well as extreme or variability in weather. The infection rate model identified temperature with an 8-month lag as a significant covariate for WNV infection rates, highlighting the importance of overwintering temperatures preceding the WNV season. These models (landscape, demographic, and meteorological conditions) can be used by local mosquito control agencies to predict WNV infection in Cx. quinquefasciatus for proactive and effective control efforts

Evaluation on Higher Education Using Data Envelopment Analysis

The goal of higher education is to provide students an equal opportunity to access their education for success. With significant competition within the peer group, potential students look for quality, flexibility, and affordability in the educational environment. In addition, the relationship between students and the institution involves a concentrated and more specific set of expectations. In order to improve students’ academic performance and fulfill individual needs, universities aim to enhance the quality of students’ learning environment and academic achievements. The higher education system relies on efficient operation and strategic planning to fulfill students’ needs through an internal emphasis on institutional performance improvement. A study on measuring the performance of higher education is presented. The research was focused on four-year and above, public and not-for-profit private universities in the southern region (AL, AR, KY, LA, MS, OK, TN, and TX) of the United States. The data includes 270 universities which were obtained from the Institute of Education Sciences, U.S. Department of Education. This study applied the Data Envelopment Analysis (DEA) approach; the purpose is to use a linear programming model to demonstrate a novel benchmarking process of higher education institutional performance and determine an overall benchmark for institutions within each classified group. From the results, suggestions are provided for the general guidance of planners and decision makers in the higher education system

Effects of data distribution and granularity on color semantics for colormap data visualizations

To create effective data visualizations, it helps to represent data using visual features in intuitive ways. When visualization designs match observer expectations, visualizations are easier to interpret. Prior work suggests that several factors influence such expectations. For example, the dark-is-more bias leads observers to infer that darker colors map to larger quantities, and the opaque-is-more bias leads them to infer that regions appearing more opaque (given the background color) map to larger quantities. Previous work suggested that the background color only plays a role if visualizations appear to vary in opacity. The present study challenges this claim. We hypothesized that the background color modulate inferred mappings for colormaps that should not appear to vary in opacity (by previous measures) if the visualization appeared to have a "hole" that revealed the background behind the map (hole hypothesis). We found that spatial aspects of the map contributed to inferred mappings, though the effects were inconsistent with the hole hypothesis. Our work raises new questions about how spatial distributions of data influence color semantics in colormap data visualizations

DEVELOPMENT AND COST ANALYSIS OF A NEW IBS SYSTEM

Conventional in-situ construction has indeed been one of the most common construction methods till date, and is being adopted in most of the construction projects in Malaysia. Despite its familiarity among designers, contractors and labours, there are many disadvantages of it, including time consuming, labour intensive, dangerous site condition and many more. Cost and time overrun due to the usage of unskilled foreign worker proves the need of shifting to a more organized method of construction, which is the Industrialized Building System (IBS)

Effect of time delay on the onset of synchronization of the stochastic Kuramoto model

We consider the Kuramoto model of globally coupled phase oscillators with time-delayed interactions, that is subject to the Ornstein-Uhlenbeck (Gaussian) colored or the non-Gaussian colored noise. We investigate numerically the interplay between the influences of the finite correlation time of noise $\tau$ and the time delay $\tau_{d}$ on the onset of the synchronization process. Both cases for identical and nonidentical oscillators had been considered. Among the obtained results for identical oscillators is a large increase of the synchronization threshold as a function of time delay for the colored non-Gaussian noise compared to the case of the colored Gaussian noise at low noise correlation time $\tau$. However, the difference reduces remarkably for large noise correlation times. For the case of nonidentical oscillators, the incoherent state may become unstable around the maximum value of the threshold (as a function of time delay) even at lower coupling strength values in the presence of colored noise as compared to the noiseless case. We had studied the dependence of the critical value of the coupling strength (the threshold of synchronization) on given parameters of the stochastic Kuramoto model in great details and presented results for possible cases of colored Gaussian and non-Gaussian noises.Comment: 19 pages with 7 figure

Bacterial Residues in Coprolite of Herbivorous Dinosaurs: Role of Bacteria in Mineralization of Feces

The Cretaceous Two Medicine Formation of northwestern Montana has yielded blocky, calcareous coprolites that contain abundant fragments of conifer wood and were produced by large herbivorous dinosaurs. The coprolites are generally dark gray to black in color due to a dark substance confined chiefly within what originally were the capillaries of tracheid and ray cells of xylem. This substance is a kerogen which consists in part of thin-walled vesicles 0.1-1.3 µm in diameter. Pyrolysis products of this kerogen are diagnostic of a bacterial origin with a possible contribution from terrestrial plants. The vesicular component is interpreted as the residue of bacterial cells, whereas a second filamentous component, closely associated with the vesicles, may be the residue of an extracellular binding material, such as glycocalyx. At least two episodes of calcification of the coprolite are recognized by manganous cathodoluminescence. The earlier of these infilled the capillary channels of the conifer fragments. Wood cell walls, voids, cracks, and small burrows were filled during the later episode. Microprobe data confirm these results and show that phosphate is sequestered in the capillaries. These observations suggest that bacteria within the capillaries induced initial mineralization of the coprolite, and, in so doing, created barriers that protected organic residues from subsequent destruction. Early onset of mineralization is consistent with the degree of preservation of woody xylem found in the coprolites

Effectiveness of implantable loop recorder and Holter electrocardiographic monitoring for the detection of arrhythmias in patients with peripartum cardiomyopathy

Background Patients with peripartum cardiomyopathy (PPCM) are at increased risk of sudden cardiac death (SCD). However, the exact underlying mechanisms of SCD in PPCM remain unknown. By means of extended electrocardiographic monitoring, we aimed to systematically characterize the burden of arrhythmias occurring in patients with newly diagnosed PPCM. Methods and results Twenty-five consecutive women with PPCM were included in this single-centre, prospective clinical trial and randomised to receiving either 24 h-Holter ECG monitoring followed by implantable loop recorder implantation (ILR; REVEAL XT, Medtronic®) or 24 h-Holter ECG monitoring alone. ILR + 24 h-Holter monitoring had a higher yield of arrhythmic events compared to 24 h-Holter monitoring alone (40% vs 6.7%, p = 0.041). Non-sustained ventricular tachycardia (NSVT) occurred in four patients (16%, in three patients detected by 24 h-Holter, and multiple episodes detected by ILR in one patient). One patient deceased from third-degree AV block with an escape rhythm that failed. All arrhythmic events occurred in patients with a severely impaired LV systolic function. Conclusions We found a high prevalence of potentially life-threatening arrhythmic events in patients with newly diagnosed PPCM. These included both brady- and tachyarrhythmias. Our results highlight the importance of extended electrocardiographic monitoring, especially in those with severely impaired LV systolic function. In this regard, ILR in addition to 24 h-Holter monitoring had a higher yield of VAs as compared to 24 h-Holter monitoring alone. In settings where WCDs are not readily available, ILR monitoring should be considered in patients with severely impaired LV systolic dysfunction, especially after uneventful 24 h-Holter monitoring

Numerical and in vitro experimental study of arterial deformation and buckling under hypertension and atherosclerotic conditions

Cardiovascular diseases remain the major cause of mortality worldwide. Pathologies of the vasculature such as atherosclerosis are often related to biochemical and genetic factors as well as mechanical effects that strongly change the function and shape of arteries. The present work is part of a general research project which aims to better understand the mechanical mechanisms responsible for atherosclerotic plaque formation and rupture. The chosen approach is to use numerical fluidstructure interaction (FSI) methods to study the relative influence of hemodynamic parameters on the structural stresses generated on plaques. To this aim, a numerical study of a simplified straight vessel exposed to lumen pressure was investigated under quiescent and steady flow conditions. As the internal pressure or the steady velocity increases, the vessel buckles lead-ing to a non-linear large deformation behaviour. The results have been validated using theoretical predictions for the buckling thresholds. Further studies on idealised cardiovascular conditions such as stenosis (i.e., lumen constriction) or aneurysm like (i.e., arterial wall expansion) formation have also been performed