614 research outputs found
An insect inspired object tracking mechanism for autonomous vehicles
No full textZahra Bagheri, Benjamin S. Cazzolato, Stevend D. Wiederman, Steven Grainger, and David C. O'Carrol
Performance assessment of an insect-inspired target tracking model in background clutter
No full textBiological visual systems provide excellent examples of robust target detection and tracking mechanisms capable of performing in a wide range of environments. Consequently, they have been sources of inspiration for many artificial vision algorithms. However, testing the robustness of target detection and tracking algorithms is a challenging task due to the diversity of environments for applications of these algorithms. Correlation between image quality metrics and model performance is one way to deal with this problem. Previously we developed a target detection model inspired by physiology of insects and implemented it in a closed loop target tracking algorithm. In the current paper we vary the kinetics of a salience-enhancing element of our algorithm and test its effect on the robustness of our model against different natural images to find the relationship between model performance and background clutter.Zahra Bagheri, Steven D. Wiederman, Benjamin S. Cazzolato, Steven Grainger, David C. O'Carrol
Synovial joints: Mechanobiology and tissue engineering of articular cartilage and synovial fluid
No full textThis chapter provides an overview of the components of synovial joints including articular cartilage, synovium, and synovial fluid. Focus is placed on the biomechanical properties of these tissues and models of their behavior. Further insight is given into the influence of mechanical loading on the development of these joint components and changes during pathology. Finally, perspectives on engineering articular cartilage and synovial fluid are provided.\ud
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Synovial joints allow for the articulation of long bones within a fluid-filled cavity. Articular cartilage (AC) is a connective tissue covering the ends of bones that functions as a load-bearing, low-friction, and wear-resistant surface to facilitate joint movement. Synovial fluid (SF) is the viscous liquid found inside synovial joints that functions as a biomechanical lubricant. The SF is encapsulated within the joint space by the synovium (SYN), a thin membrane-like tissue consisting of cells and extracellular matrix. The extracellular matrix of cartilage allows for load-bearing during joint motion, while the viscous and lubricating properties of SF reduce cartilage wear. The homeostasis of these tissues is dependent on mechanobiology – cell populations receiving mechanical cues to guide biosynthesis and thereby alter their microenvironment and tissue-scale mechanical properties. This chapter includes Tissue engineering (TE) and regenerative medicine (RM) approaches to the in vitro and in vivo development of articular cartilage and SF for the treatment and study of damaged synovial joints. First, the composition, structure, and function of cartilage and SF are discussed, followed by the mechanical properties of these tissues and the theoretical models that have been used to describe them. Next, the effects of mechanical stimuli on chondrocyte biosynthesis and pathological changes in SF composition are covered. Finally, advances in the fields of TE and RM applied to cartilaginous tissue and SF are reviewed, focusing on the mechanobiology of chondrocytes in Tissue engineered constructs
Bioengineering approaches to islet transplantation for management of diabetes
No full textHuman islet transplantation, as currently carried out by portal vein infusion in the liver, can provide good glycaemic control in diabetic patients and can significantly reduce the need to inject exogenous insulin. Perhaps the main challenge in islet transplantation is the need for life long immunosuppression which is highly undesirable due to side effects resulting in poor quality of life. Unquestionably, there has been significant progress in clinical islet transplantation, but many challenges are yet to be overcome. This calls for novel approaches to make islet based therapies more practical, sustainable and economical. By preventing adverse immune reaction and creating an environment that would reduce death of the grafted cells islet transplantation strategies can be vastly improved. Here we discuss various bioengineering approaches that are currently in development to achieve desirable outcome in islet transplantation within a clinical setting
A biologically inspired facilitation mechanism enhances the detection and pursuit of targets of varying contrast
No full textMany species of flying insects detect and chase prey or conspecifics within a visually cluttered surround, e.g. for predation, territorial or mating behavior. We modeled such detection and pursuit for small moving targets, and tested it within a closed-loop, virtual reality flight arena. Our model is inspired directly by electrophysiological recordings from ‘small target motion detector’ (STMD) neurons in the insect brain that are likely to underlie this behavioral task. The front-end uses a variant of a biologically inspired ‘elementary’ small target motion detector (ESTMD), elaborated to detect targets in natural scenes of both contrast polarities (i.e. both dark and light targets). We also include an additional model for the recently identified physiological ‘facilitation’ mechanism believed to form the basis for selective attention in insect STMDs, and quantify the improvement this provides for pursuit success and target discriminability over a range of target contrasts.Zahra M. Bagheri, Steven D. Wiederman, Benjamin S. Cazzolato, Steven Grainger, David C. O'Carrol
Letters in words are read simultaneously, not in left-to-right sequence
No full textThe identification of individual letters is necessary for reading words in alphabetic
script (Pelli, Farell, & Moore, 2003). Sequential models of letter processing (Whitney,
2001) in reading words posit an initial left-to-right sequence of letter processing (in
left-to-right languages, such as English), each letter taking 10–25 ms to process before the
next is processed. In contrast, simultaneous models of letter processing (e.g., Tydgat &
Grainger, 2009) in reading words posit that information about the identity of each letter
starts to be extracted at the same time point, regardless of horizontal position. Here we
show that people reading four-letter words do not extract identity information for any
letter from an 18 ms display of the word, but some information about all four letters is
available from 24 ms of display. Our results indicate that a left-to-right sequence of
attention across letters is not used in establishing the cognitive representation of words.
Instead, all letters are processed simultaneously
University Concert Band, April 2, 1995
No full textRecorded during a live performance at Miller Auditorium, Western Michigan University, Kalamazoo, Michigan, April 2, 1995, 3:00 p.m., the 395th concert of the School of Music’s 1994-1995 season.University Concert Band, Stephen Grugin, conductor ; Robert Spradling, conductor (2nd work).Information from performance program.Washington grays / Claudio S. Grafulla -- Grand dialogue for winds / Eugène Gigout ; arranged by William E. Rhodes -- Australian up-country tune / Percy Aldridge Grainger ; arranged by Glenn Cliffe Bainum -- Golden light : a celebration piece / David Maslanka -- Elsa’ procession to the cathedral : [from Lohengrin] / Richard Wagner ; trans. Lucien Cailliet -- Fiesta del Pacifico / Roger Nixon -- Trombone king / Karl L. King
Escherichia coli σ70 senses sequence and conformation of the promoter spacer region
No full textIn bacteria, promoter identification by RNA polymerase
is mediated by a dissociable p factor. The
housekeeping σ70 factor of Escherichia coli recognizes
two well characterized DNA sequence
elements, known as the ‘-10’ and ‘-35’ hexamers.
These elements are separated by ‘spacer’ DNA, the
sequence of which is generally considered unimportant.
Here, we use a combination of bioinformatics,
genetics and biochemistry to show that σ70
can sense the sequence and conformation of the
promoter spacer region. Our data illustrate how
alterations in spacer region sequence can increase
promoter activity. This stimulatory effect requires
σ70 side chain R451, which is located in close proximity
to the non-template strand at promoter
position -18. Conversely, R451 is not required to
mediate transcriptional stimulation by improvement
of the -10 element. Mutation of σ70 residue
R451, which is highly conserved, results in reduced
growth rate, consistent with a central role in
promoter recognition
Diminished time-based, but undiminished event-based, prospective memory among intellectually high-functioning adults with autism: Relation to working memory ability.
No full textObjective: Prospective memory (PM) is the ability to remember to carry out an intended action. Working memory is the ability to store information in mind while processing potentially distracting information. The few previous studies of PM in autism spectrum disorder (ASD) have yielded inconsistent findings. Studies of working memory ability in ASD have suggested a selective impairment of “visual working memory.” However, it remains unclear whether any such impairment is the result of diminished (domain-specific; visual/verbal) storage capacity or diminished (domain-general) processing capacity. We aim to clarify these issues and explore the relation between PM and working memory in ASD. Method: Seventeen adults with ASD and 17 age- and IQ-matched comparison participants completed experimental measures of both event-based (perform action x when event y occurs) and time-based (perform action a at time b) PM, plus a self-report measure of PM skills. Participants also completed a working memory test battery. Results: Participants with ASD self-reported diminished PM skill, and showed diminished performance on the time-based, but not event-based, PM task. On the working memory test battery, visual but not verbal storage capacity was diminished among participants with ASD, as was processing ability. Whereas visual storage was associated with event-based PM task performance among comparison participants, verbal storage was associated among ASD participants. Conclusions: ASD appears to involve a selective deficit in time-based PM and a selective difficulty with aspects of working memory that depend on the storage of visual information. However, event-based PM may be achieved through compensatory strategies in ASD
Boston University Wind Orchestra, April 10, 1969
No full textThis is the concert program of Boston University Wind Orchestra performance on Thursday, April 10, 1969 at 8:30 p.m., at the Concert Hall, 855 Commonwealth Avenue. Works performed were Lincolnshire Posy by Percy Grainger, Songs of a Wayfarer by Gustav Mahler (Howland), Concerto for Piano and Wind Instruments by Igor Stravinsky, Concerto in C for Two Trumpets by Antonio Vivaldi (Hill), Concerto for Flute by Henk Badings, Sonoric Fantasia No. 3, Op. 125 by Gardner Read, and Voyage for Winds, Brass and Percussion by Elliot Schwartz. Digitization for Boston University Concert Programs was supported by the Boston University Humanities Library Endowed Fund
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