An Efficient Algorithm For Simulating Fracture Using Large Fuse Networks

The high computational cost involved in modeling of the progressive fracture simulations using large discrete lattice networks stems from the requirement to solve {\it a new large set of linear equations} every time a new lattice bond is broken. To address this problem, we propose an algorithm that combines the multiple-rank sparse Cholesky downdating algorithm with the rank-p inverse updating algorithm based on the Sherman-Morrison-Woodbury formula for the simulation of progressive fracture in disordered quasi-brittle materials using discrete lattice networks. Using the present algorithm, the computational complexity of solving the new set of linear equations after breaking a bond reduces to the same order as that of a simple {\it backsolve} (forward elimination and backward substitution) {\it using the already LU factored matrix}. That is, the computational cost is $O(nnz({\bf L}))$, where $nnz({\bf L})$ denotes the number of non-zeros of the Cholesky factorization ${\bf L}$ of the stiffness matrix ${\bf A}$. This algorithm using the direct sparse solver is faster than the Fourier accelerated preconditioned conjugate gradient (PCG) iterative solvers, and eliminates the {\it critical slowing down} associated with the iterative solvers that is especially severe close to the critical points. Numerical results using random resistor networks substantiate the efficiency of the present algorithm.Comment: 15 pages including 1 figure. On page pp11407 of the original paper (J. Phys. A: Math. Gen. 36 (2003) 11403-11412), Eqs. 11 and 12 were misprinted that went unnoticed during the proof reading stag

The Hand that Rocks the Cradle: Maternal Gender Subversion in American Suffrage Drama

This thesis aims to shed light on the maternal role and its use in subverting feminine gender association. The maternal has always been an important facet in the construction of gender, specifically that of the feminine. By viewing three pieces of American suffrage drama: Ariana Curtis's The Spirit of '76, or The Coming Woman, a Prophetic Drama (1868), Alice Ives's A Very New Woman (1896) and Alice Thompson's A Suffragette Baby (1912), through Judith Butler's performative gender lens, we learn new things about the maternal. Most importantly, we ascertain that the maternal is an entity separate from the feminine gender, that it can be moved and that it can be reapplied to designate non-feminine bodies as maternal. This knowledge has the potential to destabilize gender construction by helping to fragment the feminine, thereby diminishing the power associated with gender as a comprehensive unit

Ultra-Sounding Maternal Subjectivity: A Feminist Reclamation of Pregnancy and Childbirth on Stage

Maternal subjectivity, as it is formed through pregnancy and birth experiences, is avoided in theatrical depiction. While particular limitations demand that the depiction of gestation be shortened in plays, what has resulted has been an over-correction that is detrimental to women, claiming that exclusively female experiences are unimportant. Theatrical conventions, such as pregnant belly costumes, bundled blankets and baby-crying sound effects, are the main culprits of this phenomena. These conventions reduce the experience of pregnancy and birth to visual or auditory cues for the audience that are communally understood in a singular way and separate it away from the woman’s own experience and identity development. Another contributor to this problem is the privileging of other characters’ perspectives over that of the gestating/birthing/maternal woman. This practice devalues the woman and reinforces damaging notions of uncontrollable hysteria that have been historically linked to the female, gestating body. I propose looking at a larger picture of the pregnant/birthing woman that encompasses more of her experience. I divide gestation into five phases: perpetually-potentially pregnant, invisibly pregnant, visibly pregnant, birthing and immediate postpartum. This extension allows for a closer look at how these experiences affect the woman. I look at six plays as case studies to see how they handle the pregnant/birthing/maternal women in their scripts. I conclude that there has been much ground covered with respect to women’s agency and autonomy in drama, but these gains have contributed an overshadowing of an essential experience for many women. Playwrights treat pregnancy and childbirth as inconsequential with respect to how they affect a woman’s identity and allowing this to continue has the potential to hinder feminist progress writ large

Applications of Machine Learning to Flight Dynamics Operations

No abstract availabl

Self-Organizing Time Map: An Abstraction of Temporal Multivariate Patterns

This paper adopts and adapts Kohonen's standard Self-Organizing Map (SOM) for exploratory temporal structure analysis. The Self-Organizing Time Map (SOTM) implements SOM-type learning to one-dimensional arrays for individual time units, preserves the orientation with short-term memory and arranges the arrays in an ascending order of time. The two-dimensional representation of the SOTM attempts thus twofold topology preservation, where the horizontal direction preserves time topology and the vertical direction data topology. This enables discovering the occurrence and exploring the properties of temporal structural changes in data. For representing qualities and properties of SOTMs, we adapt measures and visualizations from the standard SOM paradigm, as well as introduce a measure of temporal structural changes. The functioning of the SOTM, and its visualizations and quality and property measures, are illustrated on artificial toy data. The usefulness of the SOTM in a real-world setting is shown on poverty, welfare and development indicators

Free surface flows emerging from beneath a semi-infinite plate with constant vorticity

The free surface flow past a semi-infinite horizontal plate in a finite-depth fluid is considered. It is assumed that the fluid is incompressible and inviscid and that the flow approaches a uniform shear flow downstream. Exact relations are derived using conservation of mass and momentum for the case where the downstream free surface is flat. The complete nonlinear problem is solved numerically using a boundary integral method and these waveless solutions are shown to exist only when the height of the plate above the bottom is greater than the height of the uniform shear flow. Interesting results are found for various values of the constant vorticity. Solutions with downstream surface waves are also considered, and nonlinear results of this type are compared with linear results found previously. These solutions can be used to model the flow near the stern of a (two-dimensional) ship

Reproducible gene targeting in recalcitrant Escherichia coli isolates

<p>Abstract</p> <p>Background</p> <p>A number of allele replacement methods can be used to mutate bacterial genes. For instance, the Red recombinase system of phage Lambda has been used very efficiently to inactivate chromosomal genes in <it>E. coli </it>K-12, through recombination between regions of homology. However, this method does not work reproducibly in some clinical <it>E. coli </it>isolates.</p> <p>Findings</p> <p>The procedure was modified by using longer homologous regions (85 bp and 500-600 bp), to inactivate genes in the uropathogenic <it>E. coli </it>strain UTI89. An <it>lrhA </it>regulator mutant, and deletions of the <it>lac </it>operon as well as the complete <it>type 1 </it>fimbrial gene cluster, were obtained reproducibly. The modified method is also functional in other recalcitrant <it>E. coli</it>, like the avian pathogenic <it>E. coli </it>strain APEC1. The <it>lrhA </it>regulator and <it>lac </it>operon deletion mutants of APEC1 were successfully constructed in the same way as the UTI89 mutants. In other avian pathogenic <it>E. coli </it>strains (APEC3E, APEC11A and APEC16A) it was very difficult or impossible to construct these mutants, with the original Red recombinase-based method, with a Red recombinase-based method using longer (85 bp) homologous regions or with our modified protocol, using 500 - 600 bp homologous regions.</p> <p>Conclusions</p> <p>The method using 500-600 bp homologous regions can be used reliably in some clinical isolates, to delete single genes or entire operons by homologous recombination. However, it does not invariably show a greater efficiency in obtaining mutants, when compared to the original Red-mediated gene targeting method or to the gene targeting method with 85 bp homologous regions. Therefore the length of the homology regions is not the only limiting factor for the construction of mutants in these recalcitrant strains.</p

Visualizing dynamic patterns of binge and purge episodes using passive sensor data

Bulimia nervosa (BN) and binge-eating disorder (BED) are similar in that both are characterized by recurrent episodes of binge-eating, but diverge in that BN but not BED includes recurrent inappropriate compensatory behaviors to limit weight gain or counteract the effects of a binge. Binge (B) and purge (P) "events" are often conceptualized and studied as a series of brief snap shots where changing circumstances increase or decrease the likelihood of these disordered behaviors. We propose that B and P episodes can be better conceptualized as changes in patterns that unfold over time and that shifts between normative and dysfunctional patterns are observable using passive sensing methodologies and may be precluded by physiological or behavioral warning signs. In this paper, we introduce conceptual and theoretical approaches to consider B and P events from this perspective. We then use two illustrative case examples from a larger parent study to demonstrate how recent technologies can be used to collect intensive longitudinal data and how such data can be used to visualize normative and dysfunctional patterns. Finally, we close with discussion of the implications of this conceptualization and the corresponding data collection and visualization methods for basic science and intervention in eating disorders