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Search Results: 1 - 10 of 45247 matches for " Michael Shea "
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User-Friendly: Anthropomorphic Devices and Mechanical Behaviour in Japan  [PDF]
Michael Shea
Advances in Anthropology (AA) , 2014, DOI: 10.4236/aa.2014.41006
Abstract:

Anthropomorphic avatars and disembodied voices have become part of everyday life in Japan. From the animated characters that bow after you complete a transaction at an automated teller machine to the phenomenal proliferation of consumer goods bearing cute faces. There is a discernable growing tendency to anthropomorphize machines. These anthropomorphic devices stand in contrast with the somewhat automated nature of many human interactions. Particularly in the behavior required of employees that work in customer service roles, which calls to mind the demand that workers must often behave as machines from which the notion of a robot originates. Based on research conducted at the National Museum of Emerging Science and Innovation in Tokyo, examples not only of how friendliness can be mechanically produced but also of new devices being imbued with functions to demonstrate their friendliness will be critically examined.

A Proposal for a Targeted Screening Program for Renal Cancer
Michael W. Shea
Frontiers in Oncology , 2013, DOI: 10.3389/fonc.2013.00207
Abstract:
Wastewater Remediation Using Algae Grown on a Substrate for Biomass and Biofuel Production  [PDF]
James B. Houser, Mark E. Venable, Yosuke Sakamachi, Michael S. Hambourger, Jacob Herrin, Shea R. Tuberty
Journal of Environmental Protection (JEP) , 2014, DOI: 10.4236/jep.2014.510091
Abstract:

Surging oil, feed and fertilizer costs have impacted farmers particularly hard. Farm-based, local sources of renewable energy could help reduce energy costs for farmers and help develop rural-based processing and manufacturing of biofuel to bolster rural economies. At the same time, nutrient contamination and eutrophication from farming operations have become national problems. Algal-based bioprocessors have the potential to address these problems simultaneously. At Appalachian State University (Appstate) we set out to design, build and test a system that uses algae to capture wastewater nutrients as well as excreted pharmaceuticals, while simultaneously sequestering CO2, producing oil for conversion to biodiesel and feed for livestock. There are a number of problems with current algae growth systems. Algae grown in an open pond or raceway system are suspended in the water in the presence of soluble and suspended waste making most of the current harvest techniques problematic and expensive. Appstate designed algae troughs in which the algae are immobilized on a solid substrate. The laboratory-scale prototype was constructed of three-sided square plastic pipe open at the top. Inside the pipe, there was a series of cloth filters supported by rigid flow-through baffles. Preliminary results observed an average percent reduction of nitrate and phosphorous of 40 and 43, respectively, from different initial nutrient concentrations. Near complete removal (~96%) of estrogen was observed in 2-day trial experiments. In addition, effective increases in algal biomass which can serve as both biofuel feedstock and livestock feed were observed.

Are Sunspots Stabilizing?  [PDF]
Paul Shea
Theoretical Economics Letters (TEL) , 2011, DOI: 10.4236/tel.2011.13023
Abstract: The reduced form solutions of indeterminate rational expectations models often include extraneous expectational errors or “sunspots”. Sunspots are usually modeled as independent of the model’s fundamentals, and are often presumed to result in excess volatility. An alternate approach, however, is to assume that sunspots include both an overreaction or underreaction to fundamentals, as well as genuine extraneous noise. This paper uses a simple linear model to formally show how the relationship between sunspots and fundamentals affects aggregate volatility. Sunspots reduce volatility if 1) they include an undereaction to fundamentals, 2) the variance of genuine extraneous noise is sufficiently small, and 3) the root that causes indeterminacy is sufficiently far from one.
Dual Coding with STDP in a Spiking Recurrent Neural Network Model of the Hippocampus
Daniel Bush ,Andrew Philippides,Phil Husbands,Michael O'Shea
PLOS Computational Biology , 2010, DOI: 10.1371/journal.pcbi.1000839
Abstract: The firing rate of single neurons in the mammalian hippocampus has been demonstrated to encode for a range of spatial and non-spatial stimuli. It has also been demonstrated that phase of firing, with respect to the theta oscillation that dominates the hippocampal EEG during stereotype learning behaviour, correlates with an animal's spatial location. These findings have led to the hypothesis that the hippocampus operates using a dual (rate and temporal) coding system. To investigate the phenomenon of dual coding in the hippocampus, we examine a spiking recurrent network model with theta coded neural dynamics and an STDP rule that mediates rate-coded Hebbian learning when pre- and post-synaptic firing is stochastic. We demonstrate that this plasticity rule can generate both symmetric and asymmetric connections between neurons that fire at concurrent or successive theta phase, respectively, and subsequently produce both pattern completion and sequence prediction from partial cues. This unifies previously disparate auto- and hetero-associative network models of hippocampal function and provides them with a firmer basis in modern neurobiology. Furthermore, the encoding and reactivation of activity in mutually exciting Hebbian cell assemblies demonstrated here is believed to represent a fundamental mechanism of cognitive processing in the brain.
Molecular Structures of Quiescently Grown and Brain-Derived Polymorphic Fibrils of the Alzheimer Amyloid Aβ9-40 Peptide: A Comparison to Agitated Fibrils
Chun Wu,Michael T. Bowers,Joan-Emma Shea
PLOS Computational Biology , 2010, DOI: 10.1371/journal.pcbi.1000693
Abstract: The presence of amyloid deposits consisting primarily of Amyloid-β (Aβ) fibril in the brain is a hallmark of Alzheimer's disease (AD). The morphologies of these fibrils are exquisitely sensitive to environmental conditions. Using molecular dynamics simulations combined with data from previously published solid-state NMR experiments, we propose the first atomically detailed structures of two asymmetric polymorphs of the Aβ9-40 peptide fibril. The first corresponds to synthetic fibrils grown under quiescent conditions and the second to fibrils derived from AD patients' brain-extracts. Our core structure in both fibril structures consists of a layered structure in which three cross-β subunits are arranged in six tightly stacked β-sheet layers with an antiparallel hydrophobic-hydrophobic and an antiparallel polar-polar interface. The synthetic and brain-derived structures differ primarily in the side-chain orientation of one β-strand. The presence of a large and continually exposed hydrophobic surface (buried in the symmetric agitated Aβ fibrils) may account for the higher toxicity of the asymmetric fibrils. Our model explains the effects of external perturbations on the fibril lateral architecture as well as the fibrillogenesis inhibiting action of amphiphilic molecules.
The Interaction of N-Acylhomoserine Lactone Quorum Sensing Signaling Molecules with Biological Membranes: Implications for Inter-Kingdom Signaling
Benjamin Michael Davis,Rasmus Jensen,Paul Williams,Paul O'Shea
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0013522
Abstract: The long chain N-acylhomoserine lactone (AHL) quorum sensing signal molecules released by Pseudomonas aeruginosa have long been known to elicit immunomodulatory effects through a process termed inter-kingdom signaling. However, to date very little is known regarding the exact mechanism of action of these compounds on their eukaryotic targets.
Synthesis, Superoxide Dismutase Mimetic and Anticancer Activities of Metal Complexes of 2,2-Dimethylpentanedioic Acid(2dmepdaH 2 ) and 3,3-Dimethylpentanedioic acid(3dmepdaH 2 ): X-Ray Crystal Structures of [Cu(3dmepda)(bipy)] 2 6H 2 O and [Cu(2dmepda)(bipy)(EtOH)] 2 4EtOH( bipy=2, 2 ′ Bipyridine)
Michael Devereux,Malachy McCann,Denis O'Shea,Mark O'Connor
Bioinorganic Chemistry and Applications , 2006,
Abstract: 2,2-dimethylpentanedioic acid (2dmepda H 2 ) and 3,3-dimethylpentanedioic acid (3dmepda H 2 ) reacted with copper(II) acetate to give [Cu(2dmepda) ( H 2 O ) 3 ] 2 (1) and [Cu(3dmepda) ( H 2 O ) 3 ] 2 (2). Reaction of (1) and (2) with 1,10-phenanthroline and 2, 2 ′ -bipyridine yielded [Cu(2dmepda)(phen) ( H 2 O ) ] 2 0.5phen (3), [Cu(2dmepda)(bipy) ( H 2 O ) ] 2 (4), [Cu(2dmepda)(bipy)(EtOH)] 2 2EtOH (4A), [Cu(3dmepda)(phen) ( H 2 O ) ] 2 (5), and [Cu(3dmepda)(bipy) ( H 2 O ) ] 2 (6). The structures of (4A) and (6) each consists of a [Cu(bipy)(dicarboxylate) ( solvent ) ] 2 dimer. The superoxide dismutase (SOD) mimetic activity of the novel copper complexes and their manganese analogues was investigated. The dimethyl sulphoxide(DMSO) soluble complexes (1)–(4) and (6) were assessed for their cancer chemotherapeutic potential towards hepatocellular carcinoma and kidney adenocarcinoma cell lines. The 1,10-phenanthroline containing complex [Cu(2dmepda)(phen) ( H 2 O ) ] 2 0.5phen (3) was the most potent with activity that compares well to that of cisplatin.
Assessment of Polycyclic Aromatic Hydrocarbon Contamination of Breeding Pools Utilized by the Puerto Rican Crested Toad, Peltophryne lemur
Jenessa Gjeltema,Michael Stoskopf,Damian Shea,Ryan De Voe
ISRN Toxicology , 2012, DOI: 10.5402/2012/309853
Abstract: Habitat preservation and management may play an important role in the conservation of the Puerto Rican crested toad, Peltophryne lemur, due to this species’ small geographic range and declining native wild population. Bioavailable water concentrations of Polycyclic Aromatic Hydrocarbon (PAH) contaminants within breeding pools at 3 sites were established using Passive Sampling Devices (PSDs) and gas chromatography-mass spectrometry (GC/MS). A more diverse population of PAH analytes were found in higher concentrations at the breeding site that allowed direct vehicular access, but calculated risk quotients indicated low risk to toad reproduction associated with the current PAH analyte levels. 1. Introduction The Puerto Rican crested toad, Peltophryne lemur, is the only native toad species of Puerto Rico and has become a subject of conservation concern due to its small population size, limited breeding sites, and small geographic range [1–3]. Although several new populations have been established in Puerto Rico through captive-breeding and release programs, reproduction of the naturally wild population of this toad species is considered limited to a small region of coastline located in Guanica, Puerto Rico [4–8]. Based on direct observation of breeding events during heavy rainfall, the number of observed mature individuals declined from 1984 to 2003, with only 80 mature individuals recorded in 2003 [1, 9]. The majority of breeding for the naturally wild population is thought to occur at three distinct breeding sites within a several kilometer radius, and each of these three breeding sites contains at least one ephemeral pool that fills with water under adequate rainfall conditions [2]. The volume, surface area, depth, and duration of each of these temporary pools is dependent on the amount and frequency of rainfall that the region receives. A portion of the largest and most significant site for toad reproduction, the Tamarindo site, is accessible for vehicular parking by members of the public when the breeding pools are dry. This parking occurs directly over areas where breeding pools form when it rains. Vehicular traffic is associated with a wide variety of contaminants including Polycyclic Aromatic Hydrocarbons (PAHs) from incomplete combustion, exhaust, oil leaks, tire abrasion, asphalt, and other lubricants [10–14]. PAHs have been linked with many undesirable health consequences in humans and animals including carcinogenic, immunotoxic, mutagenic, and teratogenic effects [15–18]. Environmental exposure of amphibians to PAHs may cause such broad effects
Spike-timing dependent plasticity and the cognitive map
Daniel Bush,Andrew Philippides,Phil Husbands,Michael O’Shea
Frontiers in Computational Neuroscience , 2010, DOI: 10.3389/fncom.2010.00142
Abstract: Since the discovery of place cells – single pyramidal neurons that encode spatial location – it has been hypothesized that the hippocampus may act as a cognitive map of known environments. This putative function has been extensively modeled using auto-associative networks, which utilize rate-coded synaptic plasticity rules in order to generate strong bi-directional connections between concurrently active place cells that encode for neighboring place fields. However, empirical studies using hippocampal cultures have demonstrated that the magnitude and direction of changes in synaptic strength can also be dictated by the relative timing of pre- and post-synaptic firing according to a spike-timing dependent plasticity (STDP) rule. Furthermore, electrophysiology studies have identified persistent “theta-coded” temporal correlations in place cell activity in vivo, characterized by phase precession of firing as the corresponding place field is traversed. It is not yet clear if STDP and theta-coded neural dynamics are compatible with cognitive map theory and previous rate-coded models of spatial learning in the hippocampus. Here, we demonstrate that an STDP rule based on empirical data obtained from the hippocampus can mediate rate-coded Hebbian learning when pre- and post-synaptic activity is stochastic and has no persistent sequence bias. We subsequently demonstrate that a spiking recurrent neural network that utilizes this STDP rule, alongside theta-coded neural activity, allows the rapid development of a cognitive map during directed or random exploration of an environment of overlapping place fields. Hence, we establish that STDP and phase precession are compatible with rate-coded models of cognitive map development.
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