88 research outputs found
Author Correction: COVID-19 vaccine guidance for patients with cancer participating in oncology clinical trials
No full textIn the original version of this Perspective, the name of the author Giuseppe Curigliano was incorrectly written as Guiseppe Curigiliano. The affiliations have been corrected in the HTML and PDF versions of the manuscrip
Heritability of ECG biomarkers in the Netherlands twin registry measured from Holter ECGs
No full textIntroduction: The resting ECG is the most commonly used tool to assess cardiac electrophysiology. Previous studies have estimated heritability of ECG parameters based on these snapshots of the cardiac electrical activity. In this study we set out to determine whether analysis of heart rate specific data from Holter ECGs allows more complete assessment of the heritability of ECG parameters. Methods and Results: Holter ECGs were recorded from 221 twin pairs and analyzed using a multi-parameter beat binning approach. Heart rate dependent estimates of heritability for QRS duration, QT interval, Tpeak-Tend and Theight were calculated using structural equation modeling. QRS duration is largely determined by environmental factors whereas repolarization is primarily genetically determined. Heritability estimates of both QT interval and Theight were significantly higher when measured from Holter compared to resting ECGs and the heritability estimate of each was heart rate dependent. Analysis of the genetic contribution to correlation between repolarization parameters demonstrated that covariance of individual ECG parameters at different heart rates overlap but at each specific heart rate there was relatively little overlap in the genetic determinants of the different repolarization parameters. Conclusions: Here we present the first study of heritability of repolarization parameters measured from Holter ECGs. Our data demonstrate that higher heritability can be estimated from the Holter than the resting ECG and reveals rate dependence in the genetic-environmental determinants of the ECG that has not previously been tractable. Future applications include deeper dissection of the ECG of participants with inherited cardiac electrical disease.Emily C. Hodkinson, Melanie Neijts, Arash Sadrieh, Mohammad S. Imtiaz, Mathias Baumert, Rajesh N. Subbiah, Christopher S. Hayward, Dorret Boomsma, Gonneke Willemsen, JamieI.Vandenberg, Adam P. Hill, and Eco De Geu
Potential impacts of agrochemicals associated with fugitive particulate matter originating from beef cattle feed yards on native cavity-nesting bees
No full textOver the past decade it has become apparent that veterinary pharmaceuticals are aerially transported beyond beef cattle feed yard boundaries via fugitive particulate matter (PM). However, relatively little is known about the potential transport of insecticides associated with PM beyond feed yard boundaries even though they are used more heavily on a concentration basis than veterinary pharmaceuticals. In order to characterize pesticides associated with fugitive PM, and potential exposure to local pollinators, PM was collected each month from March until October and analyzed for commonly used pesticides on feed yards and row crop agriculture. The most commonly quantified insecticides in PM were then used in a 96 hour contact toxicity test on Blue orchard mason bees (Osmia lignaria) to determine toxicity to a model native pollinator. Wildflowers and co-located bees were also collected near feed yards across three field seasons to better determine agrochemical residues associated with fugitive PM on the local environment and subsequent risk to pollinators. Further, in an effort to understand the potential impacts these agrochemicals (emanating from feed yards) have on local pollinator populations, cavity nesting reed bundles were deployed near feed yards across two field seasons.
Agrochemicals were frequently detected in feed yard PM, with the most commonly identified being pyrethroids, macrocyclic lactones, and neonicotinoids. It was determined that there are enough insecticides in PM (on a per mass basis) generated across all feed yards in the United States of America to potentially kill > 1 billion bees every day. Insecticides in PM are also highly toxic to O. lignaria with neonicotinoid LD50 values < 26 ng/bee, macrocyclic lactones values < 33 ng/bee, and pyrethroid values < 290 ng/bee. Approximately one-third of wildflowers collected near feed yards contained agrochemicals at concentrations that pose elevated risks to O. lignaria and other pollinators foraging on them. Nest bundles placed near feed yards were colonized primarily by wasp species (93%), while nest bundles placed at reference sites were dominated by bee species (71%). Additionally, agrochemicals were frequently detected in all reed matrices from nest bundles deployed at feed yard sites, and at potentially lethal concentrations. Data collected throughout this dissertation suggests that highly toxic agrochemicals are aerially transported beyond feed yard boundaries, landing on local flora and fauna, and potentially impacting cavity nesting insects and other pollinators in the region.Embargo status: Restricted until 06/2026. To request the author grant access, click on the PDF link to the left
Parallel and Distributed Algorithms for a Class of Graph-Related Computational Problems.
No full textThere exist at least two models of parallel computing, namely, shared-memory and message-passing. This research addresses problems in both these types of systems, and proposes efficient parallel (Shared-Memory Model) and distributed (message-passing) algorithms for a variety of graph related computational problems. In part I, we design algorithms for three generic problems in distributed systems: set manipulation, network structure recognition and facility placement. We present optimal distributed algorithms for recognizing rectangular-mesh networks. The time and message complexity of our algorithm is linear in the number of nodes in the network. We also lay the foundation for the recognition of 2-reducible, outer-planar and cactus graphs. These algorithms have a message complexity of O(kn), where, k is the number of isolated two degree nodes in the network. We introduce the problem of reliable r-domination and design unified optimal distributed algorithms for the total, reliable and independent r-domination on trees. The time and message complexity of our algorithm is O(n), where n is the number of nodes in the tree. In the domain of set manipulation we design optimal algorithms for determining the intersection of sets in a distributed environment, where each processor is assumed to have its own set. The time and message complexity of our set intersection algorithm is O(mn), where m is the cardinality of the smallest set. In part II of our research we design optimal algorithms for r-domination and efficient parallel algorithms for the p-center problems on trees. We also present an optimal algorithm for computing the maximum independent set on intervals i the EREW-PRAM model. The r-domination problem on trees can now be solved in O(logn)time with O(n/logn) processors using the EREW-PRAM model. A parallel algorithm for range searching is developed using the concept of distributed data structures. We show that O(logn) search time can be effected for a range search on n 3-dimensional points using (2.log\sp2n-14.logn + 8) processors. Our algorithm can easily be generalized for the case of d-dimensional range search. (Abstract shortened with permission of author.)
Fast Sorting Algorithms on a Linear Array with a Reconfigurable Pipelined Bus System
No full textWe present two fast algorithms for sorting on a linear array with a recongurable pipelined bus system (LARPBS), one of the recently proposed parallel architectures based on optical buses. In our rst algorithm, we sort N numbers in O(log N log log N) worst-case time using N processors. In our second algorithm, we sort N numbers in O((log log N) 2 ) worst-case time using N 1+ processors, for any xed such that 0 < < 1. Our algorithms are based on a novel deterministic sampling scheme for merging two sorted arrays of length N each in O(log log N) time on an LARPBS with N processors. To our knowledge, the previous best sorting algorithm on this architecture has a running time of O((log N) 2 ) using N processors. Index Terms { recongurable bus, optical bus, pipelined communication, deterministic sampling, merging, sorting algorithm. This research is partially supported by an Australian Research Council (ARC) Grant. y Corresponding author. z Department of Computer Scien..
Ventricular tachycardia in hypertrophic cardiomyopathy with apical aneurysm successfully treated with left ventricular aneurysmectomy and cryoablation
No full textStudy on the improvement of silicon wafering using diamond wire process
No full textFinding a means of clean, efficient and environmentally sustainable energy is a
matter of global concern. Of the various forms of clean energy, solar energy has
matured greatly as an industry. The key component of photovoltaic cells is ultra thin
silicon (Si) wafers that are sliced from Si ingots using the multi-wire sawing
technique that uses loose abrasive slurry. However, this method has several
limitations in the form of high consumables cost and low productivity. Technological
advancements and continued research in this field has led to the development of an
innovative technique whereby diamond impregnated wires are used for sawing thus
doing away with the need for loose slurry. However, this technique also needs further
improvements for cost reduction, improved quality yield and high productivity. The
surface quality and damage are also areas of concern, which needs further study.
In this study, the author designed an experiment to investigate the interaction of
diamond with Si surface. The author used diamond tips, with included angle of 42°
and radius of 15-30μm, to perform multiple scratches on n-type single crystal Si(100)
wafers. The tips were vibrated at frequencies, 486Hz and 2kHz, to study the effect of
vibration on the scratch and wafer surface quality. In addition, the effect of varying
the cutting speed of the tool tips and effect of crystallographic orientation on the
extent of damage of the wafer surface was also examined.
The scratched wafer surfaces were analyzed under the Scanning Electron Microscope
(SEM) to study the surface morphologies of the scratches. Quantitative results of the
width and depth of scratches were obtained using the Confocal Imaging Profiler
(CIP) and finally the wafers were analyzed for possible phase transformations using
Raman Spectroscopy. It was concluded that the scratch at resonant frequency showed
maximum brittle damage while the vibration-less scratch showed dominance of
ductile damage and the width and depth of scratches increased with the increase in
cutting speed.Bachelor of Engineering (Mechanical Engineering
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