Average-cost based robust structural control

A method is presented for the synthesis of robust controllers for linear time invariant structural systems with parameterized uncertainty. The method involves minimizing quantities related to the quadratic cost (H2-norm) averaged over a set of systems described by real parameters such as natural frequencies and modal residues. Bounded average cost is shown to imply stability over the set of systems. Approximations for the exact average are derived and proposed as cost functionals. The properties of these approximate average cost functionals are established. The exact average and approximate average cost functionals are used to derive dynamic controllers which can provide stability robustness. The robustness properties of these controllers are demonstrated in illustrative numerical examples and tested in a simple SISO experiment on the MIT multi-point alignment testbed

Function generator for synthesizing complex vibration mode patterns

A simple highly flexible device for synthesizing complex vibration mode patterns is described. These mode patterns can be used to identify vibration mode data. This device sums selected sine and cosine functions and then plots the sum against a linear function

Wonders with the Sea: Rachel Carson’s Ecological Aesthetic and the Mid-Century Reader

Recent scholarship on the work of the great nature writer, Rachel Carson, posits that her landmark book, Silent Spring (1962)—often credited with igniting the modern environmental movement—is best understood in the context of her earlier, extraordinarily popular publications on the natural history of the oceans, which helped establish her as a talented and trustworthy translator of scientific concepts into literary prose. This essay builds upon that idea, showing how Carson’s The Sea Around Us (1951) and The Edge of the Sea (1955) not only shaped public understandings of ocean ecology, but also spurred a public passion for all things oceanographic, best embodied in a wave of “Carsonalia”—consumer items and experiences ranging from hats, to Book of the Month Club editions, to liner notes for the NBC Symphony’s recording of Debussy’s La Mer. While these items inspired and expressed the “sense of wonder” that was critical to Carson’s ecological aesthetic, I argue, they also subsumed the new “frontier” of the world’s oceans into the technological imperialism of the post-World War II United States. As new technologies allowed military and scientific researchers to see deeper into the oceanic depths than ever before, images of the open ocean were domesticated through consumer markets into viewable, readable, and even wearable forms. This commodification of the ocean, and of Carson’s ecocentric message, both enabled and frustrated her attempts to promote ecological literacy. Yet they also reveal much about our contemporary relationship to the world’s oceans, which remain sites of both enduring wonder and extraordinary exploitation

Multisensory Input to the Lateral Rostral Suprasylvian Sulcus (LRSS) in Ferret

For the brain to construct a comprehensive percept of the sensory world, information from the different senses must converge onto individual neurons within the central nervous system. As a consequence, how these neurons convert convergent sensory input into multisensory information is an important question facing neuroscience today. Recent physiological studies have demonstrated the presence of a robust population of multisensory neurons in the lateral bank of the rostral suprasylvian sulcus (LRSS) in adult ferret (Keniston et al, 2008). The LRSS is a region situated between somatosensory and auditory cortices, where bimodal (somatosensory-auditory) neurons occupy the greatest percentage of the sensory-responsive cell population. The present study was designed to evaluate the anatomical connections that underlie these multisensory features. Injections of neuroanatomical tracer were first made into the LRSS. After transport and histological processing, microscopy revealed retrogradely-labeled cell bodies in identified regions of cortex and thalamus. The resultant analysis showed that the greatest number of projections to LRSS originated in auditory and somatosensory cortex. Of these, auditory cortex contributed a greater proportion of inputs. These anatomical data support the idea that LRSS is a multisensory cortex that receives primarily bimodal input from auditory and somatosensory sources

Hair, Feet, Body, and Connectedness in "Song of Myself"

Examines "how Whitman\u27s positioning of the human body on horizontal and vertical axes" in "Song of Myself" illuminates his "central paradox" (that he simultaneously champions "individuality and democracy"); tracks how "horizontal orientation . . . carries democratic significance," while verticality signals individuality, with hair the image of "connectedness.

The Effect of Ethanol on Skeletal Muscle Endocrine Function and the Novel Myokines Myonectin and Irisin

Excessive alcohol consumption is a leading cause of death and disability globally and can lead to diseases such as alcoholic skeletal myopathy. Skeletal muscle is the largest organ in the human body and functions to regulate whole-body energy homeostasis. Additionally, skeletal muscle can function as an endocrine organ via secretion of myokines. Two myokines, myonectin and irisin, present a wide range of effects upon metabolism, inflammation, and tissue survival- signaling. We hypothesized that chronic alcohol consumption will result in reduced circulating myonectin and irisin levels. Mice were fed an ethanol-containing or control diet for 10 days or 6 weeks. Tissues and serum were collected from mice and immunoblotting was used to quantify myonectin and irisin levels. Our data demonstrated that neither a 10 day nor 6-week ethanol diet was effective in altering myonectin levels, whereas irisin was undetectable. Therefore, we conclude that these myokines are not affected by alcohol consumption

Cells in the Body Politic: Social identity and hospital construction in Peronist Argentina

This article examines the critical role played by social identity in the construction of hospitals in the Argentine health care sector during the 1940s and 1950s by uncovering the way in which the “jungle” of hospitals withstood attempts by the state to apply some sense of order, purpose, and centralized organization. The first section examines how physicians envisioned the “modern” hospital they hoped to construct. The second section reveals the important antecedents of nationalized hospitalization schemes found in the collaboration between physicians’ unions and the state. In the third section, an analysis of political speeches illuminates how Juan and Evita Perón packaged new hospitals as gifts to the people from their leader. The fourth section outlines specific plans to increase the number of hospital beds. The final section surveys examples of hospital construction to demonstrate how sub-national identities were instrumental to fragmenting both Argentine society and its hospital infrastructure

Genetic Differentiation of Selected Eastern Box Turtle (Terrapene carolina) Populations in Fragmented Habitats, and a Comparison of Road-based Mortality Rates to Population Size

The decline of eastern box turtle populations is associated with habitat loss and fragmentation, lack of recruitment into breeding populations, removal of individuals from the wild for pets, and road mortality. Box turtle populations in many areas of the eastern United States may effectively be isolated as high traffic volumes on roads adjacent to turtle habitats prevent successful dispersal. If so, populations surrounded by heavily used roads may be less genetically diverse than those in relatively intact habitats. I investigated whether populations in three Montgomery County, Maryland parks that were surrounded by roads were genetically differentiated relative to populations in two larger habitats in Maryland's Prince George's and Anne Arundel counties. Sampling was conducted between 2005 and 2008. I used 10 microsatellite markers to compare these populations, and sampled in an additional five sites (two in Maryland, and one each in Pennsylvania, the District of Columbia, and Florida), to better assess population structure. I found little evidence of genetic differentiation among central Maryland populations regardless of the extent of isolation. I attribute these findings to the slow rate of change in turtle evolution; the observed similarities in genetic diversity may reflect past rather than present gene flow. I found moderate to great differentiation in populations separated by substantial distances. To determine whether road mortality exceeds additive mortality levels believed to be a threat to population persistence, I estimated population size in the three Montgomery County, Maryland, parks using mark-recapture techniques, and compared these estimates to the number of dead, injured, and live turtles in or very near roads observed during walking and driving surveys conducted in 2006. Road-based morality rates fell within the range estimated to be inconsistent with population growth in one of the parks. Road mortality appeared to affect females out of proportion to their abundance in the population. Suggestions for reducing box turtle mortality in areas associated with high mortality rates are included