Wall influence on dynamics of a microbubble

The nonlinear dynamic behaviour of microscopic bubbles near a wall is investigated. The Keller-Miksis-Parlitz equation is adopted, but modified to account for the presence of the wall. This base model describes the time evolution of the bubble surface, which is assumed to remain spherical, and accounts for the effect of acoustic radiation losses owing to liquid compressibility in the momentum conservation. Two situations are considered: the base case of an isolated bubble in an unbounded medium; and a bubble near a solid wall. In the latter case, the wall influence is modeled by including a symmetrically oscillating image bubble. The bubble dynamics is traced using a numerical solution of the model equation. Subsequently, Floquet theory is used to accurately detect the bifurcation point where bubble oscillations stop following the driving ultrasound frequency and undergo period-changing bifurcations. Of particular interest is the detection of the subcritical period tripling and quadrupling transition. The parametric bifurcation maps are obtained as functions of non-dimensional parameters representing the bubble radius, the frequency and pressure amplitude of the driving ultrasound field and the distance from the wall. It is shown that the presence of the wall generally stabilises the bubble dynamics, so that much larger values of the pressure amplitude are needed to generate nonlinear responses.Comment: 25 pages, 14 figure

A study of factors related to over-achievers and under-achievers of average ability at the elementary level.

Thesis (Ed.M.)--Boston Universit

The coevolution of toxin and antitoxin genes drives the dynamics of bacterial addiction complexes and intragenomic conflict

Bacterial genomes commonly contain ‘addiction’ gene complexes that code for both a toxin and a corresponding antitoxin. As long as both genes are expressed, cells carrying the complex can remain healthy. However, loss of the complex (including segregational loss in daughter cells) can entail death of the cell. We develop a theoretical model to explore a number of evolutionary puzzles posed by toxin–antitoxin (TA) population biology. We first extend earlier results demonstrating that TA complexes can spread on plasmids, as an adaptation to plasmid competition in spatially structured environments, and highlight the role of kin selection. We then considered the emergence of TA complexes on plasmids from previously unlinked toxin and antitoxin genes. We find that one of these traits must offer at least initially a direct advantage in some but not all environments encountered by the evolving plasmid population. Finally, our study predicts non-transitive ‘rock-paper-scissors’ dynamics to be a feature of intragenomic conflict mediated by TA complexes. Intragenomic conflict could be sufficient to select deleterious genes on chromosomes and helps to explain the previously perplexing observation that many TA genes are found on bacterial chromosomes

TBI Contusion Segmentation from MRI using Convolutional Neural Networks

Traumatic brain injury (TBI) is caused by a sudden trauma to the head that may result in hematomas and contusions and can lead to stroke or chronic disability. An accurate quantification of the lesion volumes and their locations is essential to understand the pathophysiology of TBI and its progression. In this paper, we propose a fully convolutional neural network (CNN) model to segment contusions and lesions from brain magnetic resonance (MR) images of patients with TBI. The CNN architecture proposed here was based on a state of the art CNN architecture from Google, called Inception. Using a 3-layer Inception network, lesions are segmented from multi-contrast MR images. When compared with two recent TBI lesion segmentation methods, one based on CNN (called DeepMedic) and another based on random forests, the proposed algorithm showed improved segmentation accuracy on images of 18 patients with mild to severe TBI. Using a leave-one-out cross validation, the proposed model achieved a median Dice of 0.75, which was significantly better (p<0.01) than the two competing methods.Comment: https://ieeexplore.ieee.org/abstract/document/8363545/, IEEE 15th International Symposium on Biomedical Imaging (ISBI 2018

Surface Roughness Dominated Pinning Mechanism of Magnetic Vortices in Soft Ferromagnetic Films

Although pinning of domain walls in ferromagnets is ubiquitous, the absence of an appropriate characterization tool has limited the ability to correlate the physical and magnetic microstructures of ferromagnetic films with specific pinning mechanisms. Here, we show that the pinning of a magnetic vortex, the simplest possible domain structure in soft ferromagnets, is strongly correlated with surface roughness, and we make a quantitative comparison of the pinning energy and spatial range in films of various thickness. The results demonstrate that thickness fluctuations on the lateral length scale of the vortex core diameter, i.e. an effective roughness at a specific length scale, provides the dominant pinning mechanism. We argue that this mechanism will be important in virtually any soft ferromagnetic film.Comment: 4 figure

Hints for beginners in dairying

The first and most essential requirement is to teach the patrons how to take care of the milk. Everything about the dairy that the milk comes in contact with should be of tin. The milk should be thoroughly cooled and aereated immediately after it is drawn from the cow to prevent souring. In winter it should be kept in a cool room. In summer it should be set in cold water until the collector calls for it. The delivery cans should be washed out with warm water in which some sal soda has been dissolved, then scalded and rinsed in cold water, and placed out of doors to air. The milk should not be allowed to stand in these cans as it will sour more rapidly than in the common setting cans, but should be poured in just before sending to the creamery. The collector should live at the farther end of the route and start early enough to deliver the milk to the creamery by 9 o’ clock. The milk should not be allowed to freeze in winter, as it imparts a bitter taste to the butter, nor warm up in the summer above 75 degrees. Every collector should be provided with blankets to protect the milk in winter. By wetting the blankets in cold water in the summer and spreading over the cans they will keep the milk cool while on the road. The butter maker should examine every can separately to ascertain the condition of the milk before allowing it to be emptied into the weigh can, and if any defective milk is found it should be returned to the patron. One can of poor milk will injure a whole vat of good milk. In winter the milk should be partly warmed up in the receiving vat, and finished in the heating vat, as it will be easier to control the temperature that way. The milk should be at a temperature of 80 degrees never above when ready for separating. Regulate the cream outlet on the separator to take out nothing but the cream; for the thicker the cream the better the butter and less loss of butter fat in the butter milk. The skim milk should be tested every day to ascertain if the separators are doing good work; if they are not, decrease the feed and increase the speed until there is a perfect separation. The cream should be immediately cooled after separating. In winter the cooling can be done in the tempering vat, but in the summer it can be cooled to better advantage by using a cream cooler. In winter, if the milk is separated every day, the cream should be allowed to stand forty-eight hours at a temperature of 60 degrees, but if separated every other day it can be ripened in twenty-four hours, if one gallon of butter milk to one hundred gallons of cream is used as a starter

Alien Registration- Leighton, Margaret A. (Milo, Piscataquis County)

https://digitalmaine.com/alien_docs/8573/thumbnail.jp

Thomas Allies, John Henry Newman and Providentalist History

Cataloged from PDF version of article.This article discusses and evaluates the historiographical work of a leading Oxford convert and Ultramontane, Thomas Allies (1813 1903). An evaluation of Allies by the criteria of the Ultramontane scholarship he endeavoured to practise allows the article to offer an illustration of the difficulty in establishing and maintaining an autonomous Catholic scholarship during the nineteenth century’s secularising development of academic activity. It also allows substantial description of the patterns of nineteenth-century Catholic historical thought, noting the strength of its commitment to providentialism and, in particular, its apocalyptic character. An examination of the influences brought to bear on the subject’s thought during the formative period of his development as an historian, through his own study and his close friendship with John Henry Newman, indicates the reasons for Allies’s ultimate failure either to create a clear and stimulating product of the Ultramontane historical vision or to achieve an academic or popular reputation as an historian. The article argues that an unresolved conflict, between Allies’s inclination towards a providentialist historiography consistent with his commitment to a Catholic counter-culture and his willingness to accept, under Newman’s guidance, contemporary secular historiographical norms, offers substantial explanation of this failur

The Religion of the Non-Jurors and the Early British Enlightenment: a study of Henry Dodwell

Cataloged from PDF version of article.The article considers the fundamental motivations and associated theological thought of those involved in the Non-Juring schism in the Church of England in the period after the Revolution of 1688. It indicates and exemplifies how that thought is to be related to wider intellectual conflicts of the period, considered as constituting an early phase of Enlightenment/ Counter-Enlightenment debate. The works of the leading Non-Juror theologian, Henry Dodwell, and in particular his writings on the destiny of the soul, serve as an area of focus. Extensive reference is also made to the equally prominent Non-Juror, Charles Leslie. r 2002 Elsevier Science Ltd. All rights reserved

Anciennete among the Non-Jurors: a study of Henry Dodwell

Cataloged from PDF version of article.The article offers a study of the theological method of Henry Dodwell, the most distinguished British savant of the late Stuart period and a leading figure in the Non-Juring movement. The study takes the form of arguments for the extension of the contemporary dispute between the Ancients and Moderns, in its historiographical dimension, into the field of divinity; for substantial modification of the claims made in discussions of the dispute about the inherent conflict between the Renaissance’s desire for revivification of the past and its historical scholarship; and for reconsideration of the relationship between 17th century critical scholarship and the Enlightenment. r 2004 Elsevier Ltd. All rights reserved