Application of boundary integral equations to elastoplastic problems

The application of boundary integral equations to elastoplastic problems is reviewed. Details of the analysis as applied to torsion problems and to plane problems is discussed. Results are presented for the elastoplastic torsion of a square cross section bar and for the plane problem of notched beams. A comparison of different formulations as well as comparisons with experimental results are presented

Application of boundary integral method to elastoplastic analysis of V-notched beams

The boundary integral equation method was applied in the solution of the plane elastoplastic problem. The use of this method was illustrated by obtaining stress and strain distributions for a number of specimens with a single-edge notch and subjected to pure bending. The boundary integral equation method reduced the inhomogeneous biharmonic equation to two coupled Fredholm-type integral equations. These integral equations were replaced by a system of simultaneous algebraic equations and solved numerically in conjunction with a method of successive elastic solutions

Daphnia predation on the amphibian chytrid fungus and its impacts on disease risk in tadpoles

Direct predation upon parasites has the potential to reduce infection in host populations. For example, the fungal parasite of amphibians, B atrachochytrium dendrobatidis ( B d), is commonly transmitted through a free‐swimming zoospore stage that may be vulnerable to predation. Potential predators of B d include freshwater zooplankton that graze on organisms in the water column. We tested the ability of two species of freshwater crustacean ( D aphnia magna and D . dentifera ) to consume B d and to reduce B d density in water and infection in tadpoles. In a series of laboratory experiments, we allowed D aphnia to graze in water containing B d while manipulating D aphnia densities, D aphnia species identity, grazing periods and concentrations of suspended algae ( A nkistrodesmus falcatus ). We then exposed tadpoles to the grazed water. We found that high densities of D . magna reduced the amount of Bd detected in water, leading to a reduction in the proportion of tadpoles that became infected. Daphnia dentifera , a smaller species of D aphnia , also reduced B d in water samples, but did not have an effect on tadpole infection. We also found that algae affected B d in complex ways. When D aphnia were absent, less B d was detected in water and tadpole samples when concentrations of algae were higher, indicating a direct negative effect of algae on B d. When D aphnia were present, however, the amount of B d detected in water samples showed the opposite trend, with less B d when densities of algae were lower. Our results indicate that D aphnia can reduce B d levels in water and infection in tadpoles, but these effects vary with species, algal concentration, and D aphnia density. Therefore, the ability of predators to consume parasites and reduce infection is likely to vary depending on ecological context. We tested the ability of two species of freshwater crustacean ( Daphnia magna and D. dentifera ) to consume zoospores of the amphibian parasite, Batrachochytrium dendrobatidis (Bd), and to reduce parasite density in water and infection in tadpoles. In a series of laboratory experiments, we allowed Daphnia to graze in water containing Bd, then exposed tadpoles to the grazed water. Our results show that Daphnia can reduce Bd levels in water and infection in tadpoles, but these effects vary with species, algal concentration and Daphnia density.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/100311/1/ece3777.pd

Twirling Elastica: Kinks, Viscous Drag, and Torsional Stress

Biological filaments such as DNA or bacterial flagella are typically curved in their natural states. To elucidate the interplay of viscous drag, twisting, and bending in the overdamped dynamics of such filaments, we compute the steady-state torsional stress and shape of a rotating rod with a kink. Drag deforms the rod, ultimately extending or folding it depending on the kink angle. For certain kink angles and kink locations, both states are possible at high rotation rates. The agreement between our macroscopic experiments and the theory is good, with no adjustable parameters.Comment: 4 pages, 4 figure

Inclusive Masculinity and Facebook Photographs Among Early Emerging Adults at a British University

Central to debates about the construction of masculinity in sociology is the influence of culture and what constitutes acceptable displays of masculinity. This article adopts a novel approach in examining this question. It adopts a summative content analysis, combined with a semiotic analysis, of 1,100 Facebook photographs, in order to explore the underlying meanings within the photos and the performances of masculinity. Facebook photographs from 44, straight, White, male, early emerging adults attending the same university are used as a representation of an individual’s ideal self. These are then analyzed in order to determine the behaviors endorsed by peer culture. It was found that the sample overwhelmingly adopted inclusive behaviors (including homosocial tactility, dancing, and kissing each other), and inclusive masculinity theory was utilized to contextualize participants’ constructions of masculinity. Thus, this research shows that emerging adult males at this university construct their masculine identities away from previous orthodox archetypes. It is argued that the reducing importance of gendered behavior patterns may represent an adoption of what are perceived as wider cultural norms and act as a symbol of adulthood to these early emerging adults

Labels for non-individuals

Quasi-set theory is a first order theory without identity, which allows us to cope with non-individuals in a sense. A weaker equivalence relation called ``indistinguishability'' is an extension of identity in the sense that if $x$ is identical to $y$ then $x$ and $y$ are indistinguishable, although the reciprocal is not always valid. The interesting point is that quasi-set theory provides us a useful mathematical background for dealing with collections of indistinguishable elementary quantum particles. In the present paper, however, we show that even in quasi-set theory it is possible to label objects that are considered as non-individuals. We intend to prove that individuality has nothing to do with any labelling process at all, as suggested by some authors. We discuss the physical interpretation of our results.Comment: 11 pages, no figure

Memorandum on Reopening the Dodd-Frank Act Section 956 Incentive Compensation Rule

Professor Michael Herz, along with four other administrative law professors, sent a letter to six agencies about legal options regarding a long-delayed rule aimed at executive compensation

The Viscous Nonlinear Dynamics of Twist and Writhe

Exploiting the "natural" frame of space curves, we formulate an intrinsic dynamics of twisted elastic filaments in viscous fluids. A pair of coupled nonlinear equations describing the temporal evolution of the filament's complex curvature and twist density embodies the dynamic interplay of twist and writhe. These are used to illustrate a novel nonlinear phenomenon: ``geometric untwisting" of open filaments, whereby twisting strains relax through a transient writhing instability without performing axial rotation. This may explain certain experimentally observed motions of fibers of the bacterium B. subtilis [N.H. Mendelson, et al., J. Bacteriol. 177, 7060 (1995)].Comment: 9 pages, 4 figure

Spinning Interdisciplinary Service-Learning Webs: A Secondary Education Approach

Springboards: The ideas presented are not meant to be comprehensive. Placing this much information on one page restrains the number of ideas that can be given. They are meant to spark creative minds. Each teacher knows his/her students, community. and curriculum best. Making connections: Each and every curricular area does not need to participate for successful interdisciplinary learning to occur. Choosing your action: We have presented an example of each type of action: (direct, indirect, and advocacy). Only one type of action is required to make this a service-learning project along with preparation and reflection All School activities: When reading the Aging and Hunger and Homelessness webs it becomes obvious that an all school project is the focus. In the Aging web , references to holding a Senior Prom is a theme throughout. The same is true of the Hunger and Homelessness web where holding a Hunger Banquet becomes a school wide project. MSPAP and Service-learning: Service-learning and MSPAP are natural fit. Both incorporate real-life learning, problem-solving, critical thinking, and the opportunity to apply skills. Goals of this project: It is hoped that these webs accomplish 2 goals: 1- to increase understanding of service learning and its contributions to application of knowledge.2- to encourage curricular webbing that helps increase overall learning and understanding

Effective Viscosity of Dilute Bacterial Suspensions: A Two-Dimensional Model

Suspensions of self-propelled particles are studied in the framework of two-dimensional (2D) Stokesean hydrodynamics. A formula is obtained for the effective viscosity of such suspensions in the limit of small concentrations. This formula includes the two terms that are found in the 2D version of Einstein's classical result for passive suspensions. To this, the main result of the paper is added, an additional term due to self-propulsion which depends on the physical and geometric properties of the active suspension. This term explains the experimental observation of a decrease in effective viscosity in active suspensions.Comment: 15 pages, 3 figures, submitted to Physical Biolog