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Sample records for multiple photoreceptor systems

  1. Multiple photoreceptor systems control the swim pacemaker activity in box jellyfish

    Garm, Anders Lydik; Mori, S.

    2009-01-01

    Like all other cnidarian medusae, box jellyfish propel themselves through the water by contracting their bell-shaped body in discrete swim pulses. These pulses are controlled by a swim pacemaker system situated in their sensory structures, the rhopalia. Each medusa has four rhopalia each with a s......Like all other cnidarian medusae, box jellyfish propel themselves through the water by contracting their bell-shaped body in discrete swim pulses. These pulses are controlled by a swim pacemaker system situated in their sensory structures, the rhopalia. Each medusa has four rhopalia each...... with a similar set of six eyes of four morphologically different types. We have examined how each of the four eye types influences the swim pacemaker. Multiple photoreceptor systems, three of the four eye types, plus the rhopalial neuropil, affect the swim pacemaker. The lower lens eye inhibits the pacemaker...... when stimulated and provokes a strong increase in the pacemaker frequency upon light-off. The upper lens eye, the pit eyes and the rhopalial neuropil all have close to the opposite effect. When these responses are compared with all-eye stimulations it is seen that some advanced integration must take...

  2. Morphological characterization and topographic analysis of multiple photoreceptor types in the retinae of mesopelagic hatchetfishes with tubular eyes

    Lauren Michelle Biagioni

    2016-03-01

    Full Text Available Marine hatchetfishes, Argyropelecus spp., are one of the 14 genera of mesopelagic teleosts, which possess tubular eyes. The tubular eyes are positioned dorsally on the head and consist of a main retina, which subtends a large dorsal binocular field, and an accessory retina, which subtends the lateral monocular visual field. The topographic distribution of photoreceptors in the retina of Argyropelecus sladeni, A. affinis and A. aculeatus was determined using a random, unbiased and systematic stereological approach, which consistently revealed a region of high density (area centralis in the central region of the main retina (up to a peak of 96,000 receptors per mm2 and a relatively homogeneous density of photoreceptors in the accessory retina (of approximately 20,000 receptors per mm2. The position of the area centralis in the main retina indicates this retinal region subserves greater spatial resolution in the centre of the dorsal binocular visual field. Light microscopy and transmission electron microscopy also revealed the presence of multiple photoreceptor types (two rod-like and one cone-like based on the size and shape of the inner and outer segments and ultrastructural differences in the ellipsoidal region. The presence of multiple photoreceptor types in these tubular-eyed, mesopelagic hatchetfishes may reflect the need for the visual system to function under different lighting conditions during vertical migratory behavior, especially given their unique dorsally-facing eyes.

  3. Characterization of multiple light damage paradigms reveals regional differences in photoreceptor loss.

    Thomas, Jennifer L; Nelson, Craig M; Luo, Xixia; Hyde, David R; Thummel, Ryan

    2012-04-01

    Zebrafish provide an attractive model to study the retinal response to photoreceptor apoptosis due to its remarkable ability to spontaneously regenerate retinal neurons following damage. There are currently two widely-used light-induced retinal degeneration models to damage photoreceptors in the adult zebrafish. One model uses constant bright light, whereas the other uses a short exposure to extremely intense ultraviolet light. Although both models are currently used, it is unclear whether they differ in regard to the extent of photoreceptor damage or the subsequent regeneration response. Here we report a thorough analysis of the photoreceptor damage and subsequent proliferation response elicited by each individual treatment, as well as by the concomitant use of both treatments. We show a differential loss of rod and cone photoreceptors with each treatment. Additionally, we show that the extent of proliferation observed in the retina directly correlates with the severity of photoreceptor loss. We also demonstrate that both the ventral and posterior regions of the retina are partially protected from light damage. Finally, we show that combining a short ultraviolet exposure followed by a constant bright light treatment largely eliminates the neuroprotected regions, resulting in widespread loss of rod and cone photoreceptors and a robust regenerative response throughout the retina. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Characterization of Multiple Light Damage Paradigms Reveals Regional Differences in Photoreceptor Loss

    Thomas, Jennifer L.; Nelson, Craig M.; Luo, Xixia; Hyde, David R.; Thummel, Ryan

    2012-01-01

    Zebrafish provide an attractive model to study the retinal response to photoreceptor apoptosis due to its remarkable ability to spontaneously regenerate retinal neurons following damage. There are currently two widely used light-induced retinal degeneration models to damage photoreceptors in the adult zebrafish. One model uses constant bright light, whereas the other uses a short exposure to extremely intense ultraviolet light. Although both models are currently used, it is unclear whether th...

  5. Hindsight regulates photoreceptor axon targeting through transcriptional control of jitterbug/Filamin and multiple genes involved in axon guidance in Drosophila.

    Oliva, Carlos; Molina-Fernandez, Claudia; Maureira, Miguel; Candia, Noemi; López, Estefanía; Hassan, Bassem; Aerts, Stein; Cánovas, José; Olguín, Patricio; Sierralta, Jimena

    2015-09-01

    During axon targeting, a stereotyped pattern of connectivity is achieved by the integration of intrinsic genetic programs and the response to extrinsic long and short-range directional cues. How this coordination occurs is the subject of intense study. Transcription factors play a central role due to their ability to regulate the expression of multiple genes required to sense and respond to these cues during development. Here we show that the transcription factor HNT regulates layer-specific photoreceptor axon targeting in Drosophila through transcriptional control of jbug/Filamin and multiple genes involved in axon guidance and cytoskeleton organization.Using a microarray analysis we identified 235 genes whose expression levels were changed by HNT overexpression in the eye primordia. We analyzed nine candidate genes involved in cytoskeleton regulation and axon guidance, six of which displayed significantly altered gene expression levels in hnt mutant retinas. Functional analysis confirmed the role of OTK/PTK7 in photoreceptor axon targeting and uncovered Tiggrin, an integrin ligand, and Jbug/Filamin, a conserved actin- binding protein, as new factors that participate of photoreceptor axon targeting. Moreover, we provided in silico and molecular evidence that supports jbug/Filamin as a direct transcriptional target of HNT and that HNT acts partially through Jbug/Filamin in vivo to regulate axon guidance. Our work broadens the understanding of how HNT regulates the coordinated expression of a group of genes to achieve the correct connectivity pattern in the Drosophila visual system. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 75: 1018-1032, 2015. © 2015 Wiley Periodicals, Inc.

  6. Multiple rod–cone and cone–rod photoreceptor transmutations in snakes: Evidence from visual opsin gene expression

    Simoe, Bruno F; Sampaio, Filipa L.; Loew, Ellis R.; Sanders, Kate L.; Fisher, Robert N.; Hart, Nathan S.; Hunt, David M.; Partridge, Julian C.; Gower, David J.

    2016-01-01

    In 1934, Gordon Walls forwarded his radical theory of retinal photoreceptor ‘transmutation’. This proposed that rods and cones used for scotopic and photopic vision, respectively, were not fixed but could evolve into each other via a series of morphologically distinguishable intermediates. Walls' prime evidence came from series of diurnal and nocturnal geckos and snakes that appeared to have pure-cone or pure-rod retinas (in forms that Walls believed evolved from ancestors with the reverse complement) or which possessed intermediate photoreceptor cells. Walls was limited in testing his theory because the precise identity of visual pigments present in photoreceptors was then unknown. Subsequent molecular research has hitherto neglected this topic but presents new opportunities. We identify three visual opsin genes, rh1, sws1 and lws, in retinal mRNA of an ecologically and taxonomically diverse sample of snakes central to Walls' theory. We conclude that photoreceptors with superficially rod- or cone-like morphology are not limited to containing scotopic or photopic opsins, respectively. Walls' theory is essentially correct, and more research is needed to identify the patterns, processes and functional implications of transmutation. Future research will help to clarify the fundamental properties and physiology of photoreceptors adapted to function in different light levels.

  7. Gnaz couples the circadian and dopaminergic system to G protein-mediated signaling in mouse photoreceptors.

    Patrick Vancura

    Full Text Available The mammalian retina harbors a circadian clockwork that regulates vision and promotes healthiness of retinal neurons, mainly through directing the rhythmic release of the neurohormones dopamine-acting on dopamine D4 receptors-and melatonin-acting on MT1 and MT2 receptors. The gene Gnaz-a unique Gi/o subfamily member-was seen in the present study to be expressed in photoreceptors where its protein product Gαz shows a daily rhythm in its subcellular localization. Apart from subcellular localization, Gnaz displays a daily rhythm in expression-with peak values at night-in preparations of the whole retina, microdissected photoreceptors and photoreceptor-related pinealocytes. In retina, Gnaz rhythmicity was observed to persist under constant darkness and to be abolished in retina deficient for Clock or dopamine D4 receptors. Furthermore, circadian regulation of Gnaz was disturbed in the db/db mouse, a model of diabetic retinopathy. The data of the present study suggest that Gnaz links the circadian clockwork-via dopamine acting on D4 receptors-to G protein-mediated signaling in intact but not diabetic retina.

  8. Rod and cone photoreceptor cells produce ROS in response to stress in a live retinal explant system.

    Bhatt, Lavinia

    2010-01-01

    PURPOSE: The production of reactive oxygen species (ROS) can lead to oxidative stress, which is a strong contributory factor to many ocular diseases. In this study, the removal of trophic factors is used as a model system to investigate the effects of stress in the retina. The aims were to determine if both rod and cone photoreceptor cells produce ROS when they are deprived of trophic factor support and to demonstrate if the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (Nox) enzymes are responsible for this ROS production. METHODS: Retinas were explanted from mice aged between postnatal days 8-10 and cultured overnight. The following morning, confocal microscopy combined with various fluorescent probes was used to detect the production of ROS. Each time peanut agglutinin (PNA), a cone photoreceptor marker, was used to facilitate orientation of the retina. Dihydroethidium and dihydrorhodamine 123 (DHR123) were used to determine which cells produce ROS. Subsequently, western blots of retinal serial sections were used to detect the presence of Noxs in the different retinal layers. The Nox inhibitor apocynin was then tested to determine if it altered the production of ROS within these cells. RESULTS: Live retinal explants, viewed at high magnifications using confocal microscopy, displayed an increase in the fluorescent products of dihydroethidium and DHR123 upon serum removal when compared to controls. DHR123 fluorescence, once oxidized, localized to mitochondria and was found in the same focal plane as the PNA staining. This showed that cones and rods produced ROS when stressed. Retinal serial sectioning established that the photoreceptor layer expressed Nox4, dual oxidase (Duox) 1, and Duox2 at varying levels. Finally, the Nox inhibitor apocynin decreased the burst stimulated by the stress of serum removal. CONCLUSIONS: Confocal microscopy and PNA staining allowed differentiation of cell types within the outermost layers of the retina, demonstrating

  9. Laser induced photoreceptor damage and recovery in the high numerical aperture eye of the garter snake.

    Zwick, H; Edsall, P; Stuck, B E; Wood, E; Elliott, R; Cheramie, R; Hacker, H

    2008-02-01

    The garter snake provides a unique model for in-vivo imaging of photoreceptor damage induced by laser retinal exposure. Laser thermal/mechanical retinal injury induced alterations in photoreceptor structure and leukocyte cellular behavior. Photoreceptors turned white, lost mode structure, and swelled; leukocyte activity was observed in the vicinity of photoreceptor cells. Non-thermal alterations were identified with a bio-tag for oxidative stress. Mechanisms of photoreceptor recovery and replacement were observed and evaluated for active cytoskeletal systems by using an anti-actin tag that could detect the presence of active cytoskeletal systems resident in photoreceptors as well as other retinal systems.

  10. Derivation of Traceable and Transplantable Photoreceptors from Mouse Embryonic Stem Cells

    Sarah Decembrini

    2014-06-01

    Full Text Available Retinal degenerative diseases resulting in the loss of photoreceptors are one of the major causes of blindness. Photoreceptor replacement therapy is a promising treatment because the transplantation of retina-derived photoreceptors can be applied now to different murine retinopathies to restore visual function. To have an unlimited source of photoreceptors, we derived a transgenic embryonic stem cell (ESC line in which the Crx-GFP transgene is expressed in photoreceptors and assessed the capacity of a 3D culture protocol to produce integration-competent photoreceptors. This culture system allows the production of a large number of photoreceptors recapitulating the in vivo development. After transplantation, integrated cells showed the typical morphology of mature rods bearing external segments and ribbon synapses. We conclude that a 3D protocol coupled with ESCs provides a safe and renewable source of photoreceptors displaying a development and transplantation competence comparable to photoreceptors from age-matched retinas.

  11. Dynamical adaptation in photoreceptors.

    Damon A Clark

    Full Text Available Adaptation is at the heart of sensation and nowhere is it more salient than in early visual processing. Light adaptation in photoreceptors is doubly dynamical: it depends upon the temporal structure of the input and it affects the temporal structure of the response. We introduce a non-linear dynamical adaptation model of photoreceptors. It is simple enough that it can be solved exactly and simulated with ease; analytical and numerical approaches combined provide both intuition on the behavior of dynamical adaptation and quantitative results to be compared with data. Yet the model is rich enough to capture intricate phenomenology. First, we show that it reproduces the known phenomenology of light response and short-term adaptation. Second, we present new recordings and demonstrate that the model reproduces cone response with great precision. Third, we derive a number of predictions on the response of photoreceptors to sophisticated stimuli such as periodic inputs, various forms of flickering inputs, and natural inputs. In particular, we demonstrate that photoreceptors undergo rapid adaptation of response gain and time scale, over ∼ 300[Formula: see text] ms-i. e., over the time scale of the response itself-and we confirm this prediction with data. For natural inputs, this fast adaptation can modulate the response gain more than tenfold and is hence physiologically relevant.

  12. The biochemistry of photoreceptor cells

    Voaden, M.J.; Marshall, J.; Oraedu, A.C.I.

    1981-01-01

    Photoreceptor cells have high rates of metabolism, and enzyme distributions suggest considerable substrate movement. The authors have used tracer techniques to study the effects of light on photoreceptor metabolism. In vitro, glutamine is metabolized alongside glucose by rat photoreceptors, and is, potentially, a major precursor of the neuroactive amino acids glutamate, aspartate and γ-aminobutyrate (GABA). The utilization of both substrates is decreased by light, as is the turnover of glutamate and aspartate. Tritiated glutamic and aspartic acids are taken up by photoreceptor cells. In the primates all rods but only some cones are labelled, whereas in the guinea pig the picture is reversed. The observations support the premise that glutamate and/or aspartate are photoreceptor neurotransmitters but show that cell and species differences may exist. The authors have been unable to find evidence for the involvement of free radical mechanisms in high light-induced photoreceptor damage but the initial results suggest a reduced metabolism of glutamine and GABA in damaged cells. (Auth.)

  13. Different effects of valproic acid on photoreceptor loss in Rd1 and Rd10 retinal degeneration mice.

    Mitton, Kenneth P; Guzman, Alvaro E; Deshpande, Mrinalini; Byrd, David; DeLooff, Camryn; Mkoyan, Kristina; Zlojutro, Paul; Wallace, Adrianne; Metcalf, Brandon; Laux, Kirsten; Sotzen, Jason; Tran, Trung

    2014-01-01

    The histone-deacetylase inhibitor activity of valproic acid (VPA) was discovered after VPA's adoption as an anticonvulsant. This generated speculation for VPA's potential to increase the expression of neuroprotective genes. Clinical trials for retinitis pigmentosa (RP) are currently active, testing VPA's potential to reduce photoreceptor loss; however, we lack information regarding the effects of VPA on available mammalian models of retinal degeneration, nor do we know if retinal gene expression is perturbed by VPA in a predictable way. Thus, we examined the effects of systemic VPA on neurotrophic factor and Nrl-related gene expression in the mouse retina and compared VPA's effects on the rate of photoreceptor loss in two strains of mice, Pde6b(rd1/rd1) and Pde6b(rd10/rd10) . The expression of Bdnf, Gdnf, Cntf, and Fgf2 was measured by quantitative PCR after single and multiple doses of VPA (intraperitoneal) in wild-type and Pde6b(rd1/rd1) mice. Pde6b(rd1/rd1) mice were treated with daily doses of VPA during the period of rapid photoreceptor loss. Pde6b(rd10/rd10) mice were also treated with systemic VPA to compare in a partial loss-of-function model. Retinal morphology was assessed by virtual microscopy or spectral-domain optical coherence tomography (SD-OCT). Full-field and focal electroretinography (ERG) analysis were employed with Pde6b(rd10/rd10) mice to measure retinal function. In wild-type postnatal mice, a single VPA dose increased the expression of Bdnf and Gdnf in the neural retina after 18 h, while the expression of Cntf was reduced by 70%. Daily dosing of wild-type mice from postnatal day P17 to P28 resulted in smaller increases in Bdnf and Gdnf expression, normal Cntf expression, and reduced Fgf2 expression (25%). Nrl gene expression was decreased by 50%, while Crx gene expression was not affected. Rod-specific expression of Mef2c and Nr2e3 was decreased substantially by VPA treatment, while Rhodopsin and Pde6b gene expression was normal at P28. Daily

  14. Responses of photoreceptors in Hermissenda.

    Akon, D L; Fuortes, M G

    1972-12-01

    The five photoreceptors in the eye of the mollusc Hermissenda crassicornis respond to light with depolarization and firing of impulses. The impulses of any one cell inhibit other cells, but the degree of inhibition differs in different pairs. Evidence is presented to show that the interactions occur at terminal branches of the photoreceptor axons, inside the cerebropleural ganglion. Properties of the generator potential are examined and it is shown that the depolarization develops in two phases which are affected differently by extrinsic currents. Finally, it is shown that by enhancing the differences in the responses of individual cells to a variety of stimuli, the interactions may facilitate a number of simple discriminations.

  15. MULTIPLE ECH LAUNCHER CONTROL SYSTEM

    GREEN, M.T.; PONCE, D.; GRUNLOH, H.J.; ELLIS, R.A.; GROSNICKLE, W.H.; HUMPHREY, R.L.

    2004-03-01

    OAK-B135 The addition of new, high power gyrotrons to the heating and current drive arsenal at DIII-D, required a system upgrade for control of fully steerable ECH Launchers. Each launcher contains two pointing mirrors with two degrees of mechanical freedom. The two flavors of motion are called facet and tilt. Therefore up to four channels of motion per launcher need to be controlled. The system utilizes absolute encoders to indicate mirror position and therefore direction of the microwave beam. The launcher movement is primarily controlled by PLC, but future iterations of design, may require this control to be accomplished by a CPU on fast bus such as Compact PCI. This will be necessary to accomplish real time position control. Safety of equipment and personnel is of primary importance when controlling a system of moving parts. Therefore multiple interlocks and fault status enunciators have been implemented. This paper addresses the design of a Multiple ECH Launcher Control System, and characterizes the flexibility needed to upgrade to a real time position control system in the future

  16. Ultrafast spectroscopy of biological photoreceptors

    Kennis, J.T.M.; Groot, M.L.

    2007-01-01

    We review recent new insights on reaction dynamics of photoreceptors proteins gained from ultrafast spectroscopy. In Blue Light sensing Using FAD (BLUF) domains, a hydrogen-bond rearrangement around the flavin chromophore proceeds through a radical-pair mechanism, by which light-induced electron and

  17. On Dispersion in Visual Photoreceptors

    Stavenga, D.G.; Barneveld, H.H. van

    1975-01-01

    An idealized visual pigment absorbance spectrum is used together with a Kramers-Kronig dispersion relation to calculate the contribution of the visual pigment to the refractive index of the fly photoreceptor. It appears that an absorption coefficient of 0.010 µm-1 results in a refractive index

  18. Immunomodulation-accelerated neuronal regeneration following selective rod photoreceptor cell ablation in the zebrafish retina.

    White, David T; Sengupta, Sumitra; Saxena, Meera T; Xu, Qingguo; Hanes, Justin; Ding, Ding; Ji, Hongkai; Mumm, Jeff S

    2017-05-02

    Müller glia (MG) function as inducible retinal stem cells in zebrafish, completely repairing the eye after damage. The innate immune system has recently been shown to promote tissue regeneration in which classic wound-healing responses predominate. However, regulatory roles for leukocytes during cellular regeneration-i.e., selective cell-loss paradigms akin to degenerative disease-are less well defined. To investigate possible roles innate immune cells play during retinal cell regeneration, we used intravital microscopy to visualize neutrophil, macrophage, and retinal microglia responses to induced rod photoreceptor apoptosis. Neutrophils displayed no reactivity to rod cell loss. Peripheral macrophage cells responded to rod cell loss, as evidenced by morphological transitions and increased migration, but did not enter the retina. Retinal microglia displayed multiple hallmarks of immune cell activation: increased migration, translocation to the photoreceptor cell layer, proliferation, and phagocytosis of dying cells. To test function during rod cell regeneration, we coablated microglia and rod cells or applied immune suppression and quantified the kinetics of ( i ) rod cell clearance, ( ii ) MG/progenitor cell proliferation, and ( iii ) rod cell replacement. Coablation and immune suppressants applied before cell loss caused delays in MG/progenitor proliferation rates and slowed the rate of rod cell replacement. Conversely, immune suppressants applied after cell loss had been initiated led to accelerated photoreceptor regeneration kinetics, possibly by promoting rapid resolution of an acute immune response. Our findings suggest that microglia control MG responsiveness to photoreceptor loss and support the development of immune-targeted therapeutic strategies for reversing cell loss associated with degenerative retinal conditions.

  19. Usher protein functions in hair cells and photoreceptors.

    Cosgrove, Dominic; Zallocchi, Marisa

    2014-01-01

    The 10 different genes associated with the deaf/blind disorder, Usher syndrome, encode a number of structurally and functionally distinct proteins, most expressed as multiple isoforms/protein variants. Functional characterization of these proteins suggests a role in stereocilia development in cochlear hair cells, likely owing to adhesive interactions in hair bundles. In mature hair cells, homodimers of the Usher cadherins, cadherin 23 and protocadherin 15, interact to form a structural fiber, the tip link, and the linkages that anchor the taller stereocilia's actin cytoskeleton core to the shorter adjacent stereocilia and the elusive mechanotransduction channels, explaining the deafness phenotype when these molecular interactions are perturbed. The conundrum is that photoreceptors lack a synonymous mechanotransduction apparatus, and so a common theory for Usher protein function in the two neurosensory cell types affected in Usher syndrome is lacking. Recent evidence linking photoreceptor cell dysfunction in the shaker 1 mouse model for Usher syndrome to light-induced protein translocation defects, combined with localization of an Usher protein interactome at the periciliary region of the photoreceptors suggests Usher proteins might regulate protein trafficking between the inner and outer segments of photoreceptors. A distinct Usher protein complex is trafficked to the ribbon synapses of hair cells, and synaptic defects have been reported in Usher mutants in both hair cells and photoreceptors. This review aims to clarify what is known about Usher protein function at the synaptic and apical poles of hair cells and photoreceptors and the prospects for identifying a unifying pathobiological mechanism to explain deaf/blindness in Usher syndrome. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. On Utmost Multiplicity of Hierarchical Stellar Systems

    Gebrehiwot Y. M.

    2016-12-01

    Full Text Available According to theoretical considerations, multiplicity of hierarchical stellar systems can reach, depending on masses and orbital parameters, several hundred, while observational data confirm the existence of at most septuple (seven-component systems. In this study, we cross-match the stellar systems of very high multiplicity (six and more components in modern catalogues of visual double and multiple stars to find among them the candidates to hierarchical systems. After cross-matching the catalogues of closer binaries (eclipsing, spectroscopic, etc., some of their components were found to be binary/multiple themselves, what increases the system's degree of multiplicity. Optical pairs, known from literature or filtered by the authors, were flagged and excluded from the statistics. We compiled a list of hierarchical systems with potentially very high multiplicity that contains ten objects. Their multiplicity does not exceed 12, and we discuss a number of ways to explain the lack of extremely high multiplicity systems.

  1. Cellular elements for seeing in the dark: voltage-dependent conductances in cockroach photoreceptors

    Salmela Iikka

    2012-08-01

    Full Text Available Abstract Background The importance of voltage-dependent conductances in sensory information processing is well-established in insect photoreceptors. Here we present the characterization of electrical properties in photoreceptors of the cockroach (Periplaneta americana, a nocturnal insect with a visual system adapted for dim light. Results Whole-cell patch-clamped photoreceptors had high capacitances and input resistances, indicating large photosensitive rhabdomeres suitable for efficient photon capture and amplification of small photocurrents at low light levels. Two voltage-dependent potassium conductances were found in the photoreceptors: a delayed rectifier type (KDR and a fast transient inactivating type (KA. Activation of KDR occurred during physiological voltage responses induced by light stimulation, whereas KA was nearly fully inactivated already at the dark resting potential. In addition, hyperpolarization of photoreceptors activated a small-amplitude inward-rectifying (IR current mediated at least partially by chloride. Computer simulations showed that KDR shapes light responses by opposing the light-induced depolarization and speeding up the membrane time constant, whereas KA and IR have a negligible role in the majority of cells. However, larger KA conductances were found in smaller and rapidly adapting photoreceptors, where KA could have a functional role. Conclusions The relative expression of KA and KDR in cockroach photoreceptors was opposite to the previously hypothesized framework for dark-active insects, necessitating further comparative work on the conductances. In general, the varying deployment of stereotypical K+ conductances in insect photoreceptors highlights their functional flexibility in neural coding.

  2. Diagnosis of multiple system atrophy.

    Palma, Jose-Alberto; Norcliffe-Kaufmann, Lucy; Kaufmann, Horacio

    2018-05-01

    Multiple system atrophy (MSA) may be difficult to distinguish clinically from other disorders, particularly in the early stages of the disease. An autonomic-only presentation can be indistinguishable from pure autonomic failure. Patients presenting with parkinsonism may be misdiagnosed as having Parkinson disease. Patients presenting with the cerebellar phenotype of MSA can mimic other adult-onset ataxias due to alcohol, chemotherapeutic agents, lead, lithium, and toluene, or vitamin E deficiency, as well as paraneoplastic, autoimmune, or genetic ataxias. A careful medical history and meticulous neurological examination remain the cornerstone for the accurate diagnosis of MSA. Ancillary investigations are helpful to support the diagnosis, rule out potential mimics, and define therapeutic strategies. This review summarizes diagnostic investigations useful in the differential diagnosis of patients with suspected MSA. Currently used techniques include structural and functional brain imaging, cardiac sympathetic imaging, cardiovascular autonomic testing, olfactory testing, sleep study, urological evaluation, and dysphagia and cognitive assessments. Despite advances in the diagnostic tools for MSA in recent years and the availability of consensus criteria for clinical diagnosis, the diagnostic accuracy of MSA remains sub-optimal. As other diagnostic tools emerge, including skin biopsy, retinal biomarkers, blood and cerebrospinal fluid biomarkers, and advanced genetic testing, a more accurate and earlier recognition of MSA should be possible, even in the prodromal stages. This has important implications as misdiagnosis can result in inappropriate treatment, patient and family distress, and erroneous eligibility for clinical trials of disease-modifying drugs. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Knock-in strategy at 3'-end of Crx gene by CRISPR/Cas9 system shows the gene expression profiles during human photoreceptor differentiation.

    Homma, Kohei; Usui, Sumiko; Kaneda, Makoto

    2017-03-01

    Fluorescent reporter gene knock-in induced pluripotent stem cell (iPSC) lines have been used to evaluate the efficiency of differentiation into specific cell lineages. Here, we report a knock-in strategy for the generation of human iPSC reporter lines in which a 2A peptide sequence and a red fluorescent protein (E2-Crimson) gene were inserted at the termination codon of the cone-rod homeobox (Crx) gene, a photoreceptor-specific transcriptional factor gene. The knock-in iPSC lines were differentiated into fluorescence-expressing cells in 3D retinal differentiation culture, and the fluorescent cells also expressed Crx specifically in the nucleus. We found that the fluorescence intensity was positively correlated with the expression levels of Crx mRNA and that fluorescent cells expressed rod photoreceptor-specific genes in the later stage of differentiation. Finally, we treated the fluorescent cells with DAPT, a Notch inhibitor, and found that DAPT-enhanced retinal differentiation was associated with up-regulation of Crx, Otx2 and NeuroD1, and down-regulation of Hes5 and Ngn2. These suggest that this knock-in strategy at the 3'-end of the target gene, combined with the 2A peptide linked to fluorescent proteins, offers a useful tool for labeling specific cell lineages or monitoring expression of any marker genes without affecting the function of the target gene. © 2017 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.

  4. Applications of hydrogen deuterium exchange (HDX for the characterization of conformational dynamics in light-activated photoreceptors

    Robert eLindner

    2015-06-01

    Full Text Available Rational design of optogenetic tools is inherently linked to the understanding of photoreceptor function. Structural analysis of elements involved in signal integration in individual sensor domains provides an initial idea of their mode of operation, but understanding how local structural rearrangements eventually affect signal transmission to output domains requires inclusion of the effector regions in the characterization. However, the dynamic nature of these assemblies renders their structural analysis challenging and therefore a combination of high- and low-resolution techniques is required to appreciate functional aspects of photoreceptors.This review focuses on the potential of Hydrogen-Deuterium exchange coupled to mass spectrometry (HDX-MS for complementing the structural characterization of photoreceptors. In this respect, the ability of HDX-MS to provide information on the conformational dynamics and the possibility to address multiple functionally relevant states in solution render this methodology ideally suitable. We highlight recent examples demonstrating the potential of HDX-MS and discuss how these results can help to improve existing optogenetic systems or guide the design of novel optogenetic tools.

  5. Rax Homeoprotein Regulates Photoreceptor Cell Maturation and Survival in Association with Crx in the Postnatal Mouse Retina.

    Irie, Shoichi; Sanuki, Rikako; Muranishi, Yuki; Kato, Kimiko; Chaya, Taro; Furukawa, Takahisa

    2015-08-01

    The Rax homeobox gene plays essential roles in multiple processes of vertebrate retina development. Many vertebrate species possess Rax and Rax2 genes, and different functions have been suggested. In contrast, mice contain a single Rax gene, and its functional roles in late retinal development are still unclear. To clarify mouse Rax function in postnatal photoreceptor development and maintenance, we generated conditional knockout mice in which Rax in maturing or mature photoreceptor cells was inactivated by tamoxifen treatment (Rax iCKO mice). When Rax was inactivated in postnatal Rax iCKO mice, developing photoreceptor cells showed a significant decrease in the level of the expression of rod and cone photoreceptor genes and mature adult photoreceptors exhibited a specific decrease in cone cell numbers. In luciferase assays, we found that Rax and Crx cooperatively transactivate Rhodopsin and cone opsin promoters and that an optimum Rax expression level to transactivate photoreceptor gene expression exists. Furthermore, Rax and Crx colocalized in maturing photoreceptor cells, and their coimmunoprecipitation was observed in cultured cells. Taken together, these results suggest that Rax plays essential roles in the maturation of both cones and rods and in the survival of cones by regulating photoreceptor gene expression with Crx in the postnatal mouse retina. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  6. Restoration of vision after transplantation of photoreceptors.

    Pearson, R A; Barber, A C; Rizzi, M; Hippert, C; Xue, T; West, E L; Duran, Y; Smith, A J; Chuang, J Z; Azam, S A; Luhmann, U F O; Benucci, A; Sung, C H; Bainbridge, J W; Carandini, M; Yau, K-W; Sowden, J C; Ali, R R

    2012-05-03

    Cell transplantation is a potential strategy for treating blindness caused by the loss of photoreceptors. Although transplanted rod-precursor cells are able to migrate into the adult retina and differentiate to acquire the specialized morphological features of mature photoreceptor cells, the fundamental question remains whether transplantation of photoreceptor cells can actually improve vision. Here we provide evidence of functional rod-mediated vision after photoreceptor transplantation in adult Gnat1−/− mice, which lack rod function and are a model of congenital stationary night blindness. We show that transplanted rod precursors form classic triad synaptic connections with second-order bipolar and horizontal cells in the recipient retina. The newly integrated photoreceptor cells are light-responsive with dim-flash kinetics similar to adult wild-type photoreceptors. By using intrinsic imaging under scotopic conditions we demonstrate that visual signals generated by transplanted rods are projected to higher visual areas, including V1. Moreover, these cells are capable of driving optokinetic head tracking and visually guided behaviour in the Gnat1−/− mouse under scotopic conditions. Together, these results demonstrate the feasibility of photoreceptor transplantation as a therapeutic strategy for restoring vision after retinal degeneration.

  7. Plasticity of photoreceptor-generating retinal progenitors revealed by prolonged retinoic acid exposure

    Cameron David A

    2011-08-01

    Full Text Available Abstract Background Retinoic acid (RA is important for vertebrate eye morphogenesis and is a regulator of photoreceptor development in the retina. In the zebrafish, RA treatment of postmitotic photoreceptor precursors has been shown to promote the differentiation of rods and red-sensitive cones while inhibiting the differentiation of blue- and UV-sensitive cones. The roles played by RA and its receptors in modifying photoreceptor fate remain to be determined. Results Treatment of zebrafish embryos with RA, beginning at the time of retinal progenitor cell proliferation and prior to photoreceptor terminal mitosis, resulted in a significant alteration of rod and cone mosaic patterns, suggesting an increase in the production of rods at the expense of red cones. Quantitative pattern analyses documented increased density of rod photoreceptors and reduced local spacing between rod cells, suggesting rods were appearing in locations normally occupied by cone photoreceptors. Cone densities were correspondingly reduced and cone photoreceptor mosaics displayed expanded and less regular spacing. These results were consistent with replacement of approximately 25% of positions normally occupied by red-sensitive cones, with additional rods. Analysis of embryos from a RA-signaling reporter line determined that multiple retinal cell types, including mitotic cells and differentiating rods and cones, are capable of directly responding to RA. The RA receptors RXRγ and RARαb are expressed in patterns consistent with mediating the effects of RA on photoreceptors. Selective knockdown of RARαb expression resulted in a reduction in endogenous RA signaling in the retina. Knockdown of RARαb also caused a reduced production of rods that was not restored by simultaneous treatments with RA. Conclusions These data suggest that developing retinal cells have a dynamic sensitivity to RA during retinal neurogenesis. In zebrafish RA may influence the rod vs. cone cell fate

  8. Photoreceptor Sensory Cilium: Traversing the Ciliary Gate

    Hemant Khanna

    2015-10-01

    Full Text Available Cilia are antenna-like extensions of the plasma membrane found in nearly all cell types. In the retina of the eye, photoreceptors develop unique sensory cilia. Not much was known about the mechanisms underlying the formation and function of photoreceptor cilia, largely because of technical limitations and the specific structural and functional modifications that cannot be modeled in vitro. With recent advances in microscopy techniques and molecular and biochemical approaches, we are now beginning to understand the molecular basis of photoreceptor ciliary architecture, ciliary function and its involvement in human diseases. Here, I will discuss the studies that have revealed new knowledge of how photoreceptor cilia regulate their identity and function while coping with high metabolic and trafficking demands associated with processing light signal.

  9. Chemically-induced photoreceptor degeneration and protection in mouse iPSC-derived three-dimensional retinal organoids

    Shin-ichiro Ito

    2017-10-01

    Full Text Available Induced pluripotent stem cells (iPSCs, which can be differentiated into various tissues and cell types, have been used for clinical research and disease modeling. Self-organizing three-dimensional (3D tissue engineering has been established within the past decade and enables researchers to obtain tissues and cells that almost mimic in vivo development. However, there are no reports of practical experimental procedures that reproduce photoreceptor degeneration. In this study, we induced photoreceptor cell death in mouse iPSC-derived 3D retinal organoids (3D-retinas by 4-hydroxytamoxifen (4-OHT, which induces photoreceptor degeneration in mouse retinal explants, and then established a live-cell imaging system to measure degeneration-related properties. Furthermore, we quantified the protective effects of representative ophthalmic supplements for treating the photoreceptor degeneration. This drug evaluation system enables us to monitor drug effects in photoreceptor cells and could be useful for drug screening.

  10. The influence of photoreceptor size and distribution on optical sensitivity in the eyes of lanternfishes (Myctophidae)

    Busserolles, Fanny de

    2014-06-13

    The mesopelagic zone of the deep-sea (200-1000 m) is characterised by exponentially diminishing levels of downwelling sunlight and by the predominance of bioluminescence emissions. The ability of mesopelagic organisms to detect and behaviourally react to downwelling sunlight and/or bioluminescence will depend on the visual task and ultimately on the eyes and their capacity for detecting low levels of illumination and intermittent point sources of bioluminescent light. In this study, we investigate the diversity of the visual system of the lanternfish (Myctophidae). We focus specifically on the photoreceptor cells by examining their size, arrangement, topographic distribution and contribution to optical sensitivity in 53 different species from 18 genera. We also examine the influence(s) of both phylogeny and ecology on these photoreceptor variables using phylogenetic comparative analyses in order to understand the constraints placed on the visual systems of this large group of mesopelagic fishes at the first stage of retinal processing. We report great diversity in the visual system of the Myctophidae at the level of the photoreceptors. Photoreceptor distribution reveals clear interspecific differences in visual specialisations (areas of high rod photoreceptor density), indicating potential interspecific differences in interactions with prey, predators and/or mates. A great diversity in photoreceptor design (length and diameter) and density is also present. Overall, the myctophid eye is very sensitive compared to other teleosts and each species seems to be specialised for the detection of a specific signal (downwelling light or bioluminescence), potentially reflecting different visual demands for survival. Phylogenetic comparative analyses highlight several relationships between photoreceptor characteristics and the ecological variables tested (depth distribution and luminous tissue patterns). Depth distribution at night was a significant factor in most of the

  11. The influence of photoreceptor size and distribution on optical sensitivity in the eyes of lanternfishes (Myctophidae)

    Busserolles, Fanny de; Fitzpatrick, John L.; Marshall, N. Justin; Collin, Shaun P.

    2014-01-01

    The mesopelagic zone of the deep-sea (200-1000 m) is characterised by exponentially diminishing levels of downwelling sunlight and by the predominance of bioluminescence emissions. The ability of mesopelagic organisms to detect and behaviourally react to downwelling sunlight and/or bioluminescence will depend on the visual task and ultimately on the eyes and their capacity for detecting low levels of illumination and intermittent point sources of bioluminescent light. In this study, we investigate the diversity of the visual system of the lanternfish (Myctophidae). We focus specifically on the photoreceptor cells by examining their size, arrangement, topographic distribution and contribution to optical sensitivity in 53 different species from 18 genera. We also examine the influence(s) of both phylogeny and ecology on these photoreceptor variables using phylogenetic comparative analyses in order to understand the constraints placed on the visual systems of this large group of mesopelagic fishes at the first stage of retinal processing. We report great diversity in the visual system of the Myctophidae at the level of the photoreceptors. Photoreceptor distribution reveals clear interspecific differences in visual specialisations (areas of high rod photoreceptor density), indicating potential interspecific differences in interactions with prey, predators and/or mates. A great diversity in photoreceptor design (length and diameter) and density is also present. Overall, the myctophid eye is very sensitive compared to other teleosts and each species seems to be specialised for the detection of a specific signal (downwelling light or bioluminescence), potentially reflecting different visual demands for survival. Phylogenetic comparative analyses highlight several relationships between photoreceptor characteristics and the ecological variables tested (depth distribution and luminous tissue patterns). Depth distribution at night was a significant factor in most of the

  12. Multiple Antenna Systems with Inherently Decoupled Radiators

    Pelosi, Mauro; Knudsen, Mikael B.; Pedersen, Gert Frølund

    2012-01-01

    In multiple antenna systems mutual coupling needs to be minimized. We propose an alternative novel decoupling technique, investigating several multiple antenna configurations for small handsets through measurements and numerical simulations. The influence of different novel designs on performance...... metrics such as total loss, antenna isolation and envelope correlation coefficient are investigated. By varying antenna impedance bandwidth and antenna location with respect to the handset, both Planar Inverted F Antenna (PIFA) and Inverted F Antennas (IFA) were investigated in different UMTS frequency...

  13. Spacecraft Multiple Array Communication System Performance Analysis

    Hwu, Shian U.; Desilva, Kanishka; Sham, Catherine C.

    2010-01-01

    The Communication Systems Simulation Laboratory (CSSL) at the NASA Johnson Space Center is tasked to perform spacecraft and ground network communication system simulations, design validation, and performance verification. The CSSL has developed simulation tools that model spacecraft communication systems and the space and ground environment in which the tools operate. In this paper, a spacecraft communication system with multiple arrays is simulated. Multiple array combined technique is used to increase the radio frequency coverage and data rate performance. The technique is to achieve phase coherence among the phased arrays to combine the signals at the targeting receiver constructively. There are many technical challenges in spacecraft integration with a high transmit power communication system. The array combining technique can improve the communication system data rate and coverage performances without increasing the system transmit power requirements. Example simulation results indicate significant performance improvement can be achieved with phase coherence implementation.

  14. Samd7 is a cell type-specific PRC1 component essential for establishing retinal rod photoreceptor identity.

    Omori, Yoshihiro; Kubo, Shun; Kon, Tetsuo; Furuhashi, Mayu; Narita, Hirotaka; Kominami, Taro; Ueno, Akiko; Tsutsumi, Ryotaro; Chaya, Taro; Yamamoto, Haruka; Suetake, Isao; Ueno, Shinji; Koseki, Haruhiko; Nakagawa, Atsushi; Furukawa, Takahisa

    2017-09-26

    Precise transcriptional regulation controlled by a transcription factor network is known to be crucial for establishing correct neuronal cell identities and functions in the CNS. In the retina, the expression of various cone and rod photoreceptor cell genes is regulated by multiple transcription factors; however, the role of epigenetic regulation in photoreceptor cell gene expression has been poorly understood. Here, we found that Samd7, a rod-enriched sterile alpha domain (SAM) domain protein, is essential for silencing nonrod gene expression through H3K27me3 regulation in rod photoreceptor cells. Samd7- null mutant mice showed ectopic expression of nonrod genes including S-opsin in rod photoreceptor cells and rod photoreceptor cell dysfunction. Samd7 physically interacts with Polyhomeotic homologs (Phc proteins), components of the Polycomb repressive complex 1 (PRC1), and colocalizes with Phc2 and Ring1B in Polycomb bodies. ChIP assays showed a significant decrease of H3K27me3 in the genes up-regulated in the Samd7 -deficient retina, showing that Samd7 deficiency causes the derepression of nonrod gene expression in rod photoreceptor cells. The current study suggests that Samd7 is a cell type-specific PRC1 component epigenetically defining rod photoreceptor cell identity.

  15. Chemically induced and light-independent cryptochrome photoreceptor activation.

    Rosenfeldt, Gesa; Viana, Rafael Muñoz; Mootz, Henning D; von Arnim, Albrecht G; Batschauer, Alfred

    2008-01-01

    The cryptochrome photoreceptors of higher plants are dimeric proteins. Their N-terminal photosensory domain mediates dimerization, and the unique C-terminal extension (CCT) mediates signaling. We made use of the human FK506-binding protein (FKBP) that binds with high affinity to rapamycin or rapamycin analogs (rapalogs). The FKBP-rapamycin complex is recognized by another protein, FRB, thus allowing rapamycin-induced dimerization of two target proteins. Here we demonstrate by bioluminescence resonance energy transfer (BRET) assays the applicability of this regulated dimerization system to plants. Furthermore, we show that fusion proteins consisting of the C-terminal domain of Arabidopsis cryptochrome 2 fused to FKBP and FRB and coexpressed in Arabidopsis cells specifically induce the expression of cryptochrome-controlled reporter and endogenous genes in darkness upon incubation with the rapalog. These results demonstrate that the activation of cryptochrome signal transduction can be chemically induced in a dose-dependent fashion and uncoupled from the light signal, and provide the groundwork for gain-of-function experiments to study specifically the role of photoreceptors in darkness or in signaling cross-talk even under light conditions that activate members of all photoreceptor families.

  16. Vulnerability of multiple-barrier systems

    Lind, N.C.

    1996-01-01

    'Vulnerability' is defined as the ratio of the probability of failure of a damaged system to the probability of failure of the undamaged system. This definition applies to all engineered systems and can be specialized to particular system types. Some disastrous failures (e.g., Chernobyl) have shown that systems can be highly vulnerable. open-quotes Defense in depthclose quotes is a powerful design principle, reducing vulnerability when the consequences of failure can be catastrophic. In the nuclear industry, defense in depth is widely used in radiation protection, reactor control, and shutdown systems. A multiple-barrier system is a simple example of a system that has defense in depth. The idea is that the system is not vulnerable. It cannot fail if one barrier fails because there is another to take its place. This idea is untenable in waste management, but a quantified vulnerability of a system can help owners, designers, and regulators decide how much defense in depth is desirable or enough. Many multiple-barrier systems can be modeled as systems of components physically in a series, each individually able to prevent failure. Components typically have bimodal distributions of the service time to failure, as illustrated by an example of application to a hypothetical nuclear fuel waste repository

  17. Stress Effects on Multiple Memory System Interactions

    Ness, Deborah; Calabrese, Pasquale

    2016-01-01

    Extensive behavioural, pharmacological, and neurological research reports stress effects on mammalian memory processes. While stress effects on memory quantity have been known for decades, the influence of stress on multiple memory systems and their distinct contributions to the learning process have only recently been described. In this paper, after summarizing the fundamental biological aspects of stress/emotional arousal and recapitulating functionally and anatomically distinct memory systems, we review recent animal and human studies exploring the effects of stress on multiple memory systems. Apart from discussing the interaction between distinct memory systems in stressful situations, we will also outline the fundamental role of the amygdala in mediating such stress effects. Additionally, based on the methods applied in the herein discussed studies, we will discuss how memory translates into behaviour. PMID:27034845

  18. Stress Effects on Multiple Memory System Interactions

    Deborah Ness

    2016-01-01

    Full Text Available Extensive behavioural, pharmacological, and neurological research reports stress effects on mammalian memory processes. While stress effects on memory quantity have been known for decades, the influence of stress on multiple memory systems and their distinct contributions to the learning process have only recently been described. In this paper, after summarizing the fundamental biological aspects of stress/emotional arousal and recapitulating functionally and anatomically distinct memory systems, we review recent animal and human studies exploring the effects of stress on multiple memory systems. Apart from discussing the interaction between distinct memory systems in stressful situations, we will also outline the fundamental role of the amygdala in mediating such stress effects. Additionally, based on the methods applied in the herein discussed studies, we will discuss how memory translates into behaviour.

  19. Stress Effects on Multiple Memory System Interactions.

    Ness, Deborah; Calabrese, Pasquale

    2016-01-01

    Extensive behavioural, pharmacological, and neurological research reports stress effects on mammalian memory processes. While stress effects on memory quantity have been known for decades, the influence of stress on multiple memory systems and their distinct contributions to the learning process have only recently been described. In this paper, after summarizing the fundamental biological aspects of stress/emotional arousal and recapitulating functionally and anatomically distinct memory systems, we review recent animal and human studies exploring the effects of stress on multiple memory systems. Apart from discussing the interaction between distinct memory systems in stressful situations, we will also outline the fundamental role of the amygdala in mediating such stress effects. Additionally, based on the methods applied in the herein discussed studies, we will discuss how memory translates into behaviour.

  20. Spiking neural P systems with multiple channels.

    Peng, Hong; Yang, Jinyu; Wang, Jun; Wang, Tao; Sun, Zhang; Song, Xiaoxiao; Luo, Xiaohui; Huang, Xiangnian

    2017-11-01

    Spiking neural P systems (SNP systems, in short) are a class of distributed parallel computing systems inspired from the neurophysiological behavior of biological spiking neurons. In this paper, we investigate a new variant of SNP systems in which each neuron has one or more synaptic channels, called spiking neural P systems with multiple channels (SNP-MC systems, in short). The spiking rules with channel label are introduced to handle the firing mechanism of neurons, where the channel labels indicate synaptic channels of transmitting the generated spikes. The computation power of SNP-MC systems is investigated. Specifically, we prove that SNP-MC systems are Turing universal as both number generating and number accepting devices. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Activin Signals through SMAD2/3 to Increase Photoreceptor Precursor Yield during Embryonic Stem Cell Differentiation.

    Lu, Amy Q; Popova, Evgenya Y; Barnstable, Colin J

    2017-09-12

    In vitro differentiation of mouse embryonic stem cells (ESCs) into retinal fates can be used to study the roles of exogenous factors acting through multiple signaling pathways during retina development. Application of activin A during a specific time frame that corresponds to early embryonic retinogenesis caused increased generation of CRX + photoreceptor precursors and decreased PAX6 + retinal progenitor cells (RPCs). Following activin A treatment, SMAD2/3 was activated in RPCs and bound to promoter regions of key RPC and photoreceptor genes. The effect of activin on CRX expression was repressed by pharmacological inhibition of SMAD2/3 phosphorylation. Activin signaling through SMAD2/3 in RPCs regulates expression of transcription factors involved in cell type determination and promotes photoreceptor lineage specification. Our findings can contribute to the production of photoreceptors for cell replacement therapy. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  2. Multiple equilibria in a simple elastocapillary system

    Taroni, Michele

    2012-09-28

    We consider the elastocapillary interaction of a liquid drop placed between two elastic beams, which are both clamped at one end to a rigid substrate. This is a simple model system relevant to the problem of surface-tension-induced collapse of flexible micro-channels that has been observed in the manufacture of microelectromechanical systems (MEMS). We determine the conditions under which the beams remain separated, touch at a point, or stick along a portion of their length. Surprisingly, we show that in many circumstances multiple equilibrium states are possible. We develop a lubrication-type model for the flow of liquid out of equilibrium and thereby investigate the stability of the multiple equilibria. We demonstrate that for given material properties two stable equilibria may exist, and show via numerical solutions of the dynamic model that it is the initial state of the system that determines which stable equilibrium is ultimately reached. © 2012 Cambridge University Press.

  3. An N-Terminal ER Export Signal Facilitates the Plasma Membrane Targeting of HCN1 Channels in Photoreceptors.

    Pan, Yuan; Laird, Joseph G; Yamaguchi, David M; Baker, Sheila A

    2015-06-01

    Hyperpolarization-activated cyclic nucleotide-gated 1 (HCN1) channels are widely expressed in the retina. In photoreceptors, the hyperpolarization-activated current (Ih) carried by HCN1 is important for shaping the light response. It has been shown in multiple systems that trafficking HCN1 channels to specific compartments is key to their function. The localization of HCN1 in photoreceptors is concentrated in the plasma membrane of the inner segment (IS). The mechanisms controlling this localization are not understood. We previously identified a di-arginine endoplasmic reticulum (ER) retention motif that negatively regulates the surface targeting of HCN1. In this study, we sought to identify a forward trafficking signal that could counter the function of the ER retention signal. We studied trafficking of HCN1 and several mutants by imaging their subcellular localization in transgenic X. laevis photoreceptors. Velocity sedimentation was used to assay the assembly state of HCN1 channels. We found the HCN1 N-terminus can redirect a membrane reporter from outer segments (OS) to the plasma membrane of the IS. The sequence necessary for this behavior was mapped to a 20 amino acid region containing a leucine-based ER export motif. The ER export signal is necessary for forward trafficking but not channel oligomerization. Moreover, this ER export signal alone counteracted the di-arginine ER retention signal. We identified an ER export signal in HCN1 that functions with the ER retention signal to maintain equilibrium of HCN1 between the endomembrane system and the plasma membrane.

  4. UNIVERSAL INTERFACE TO MULTIPLE OPERATIONS SYSTEMS

    Sonnenwald, Diane H.

    1986-01-01

    Alternative ways to provide access to operations systems that maintain, test, and configure complex telephone networks are being explored. It is suggested that a universal interface that provides simultaneous access to multiple operations systems that execute in different hardware and software...... environments, can be provided by an architecture that is based on the separation of presentation issues from application issues and on a modular interface management system that consists of a virtual user interface, physical user interface, and interface agent. The interface functionality that is needed...

  5. Delegation control of multiple unmanned systems

    Flaherty, Susan R.; Shively, Robert J.

    2010-04-01

    Maturing technologies and complex payloads coupled with a future objective to reduce the logistics burden of current unmanned aerial systems (UAS) operations require a change to the 2-crew employment paradigm. Increased automation and operator supervisory control of unmanned systems have been advocated to meet the objective of reducing the crew requirements, while managing future technologies. Specifically, a delegation control employment strategy has resulted in reduced workload and higher situation awareness for single operators controlling multiple unmanned systems in empirical studies1,2. Delegation control is characterized by the ability for an operator to call a single "play" that initiates prescribed default actions for each vehicle and associated sensor related to a common mission goal. Based upon the effectiveness of delegation control in simulation, the U.S. Army Aeroflightdynamics Directorate (AFDD) developed a Delegation Control (DelCon) operator interface with voice recognition implementation for play selection, real-time play modification, and play status with automation transparency to enable single operator control of multiple unmanned systems in flight. AFDD successfully demonstrated delegation control in a Troops-in-Contact mission scenario at Ft. Ord in 2009. This summary showcases the effort as a beneficial advance in single operator control of multiple UAS.

  6. MPACT Fast Neutron Multiplicity System Prototype Development

    D.L. Chichester; S.A. Pozzi; J.L. Dolan; M.T. Kinlaw; S.J. Thompson; A.C. Kaplan; M. Flaska; A. Enqvist; J.T. Johnson; S.M. Watson

    2013-09-01

    This document serves as both an FY2103 End-of-Year and End-of-Project report on efforts that resulted in the design of a prototype fast neutron multiplicity counter leveraged upon the findings of previous project efforts. The prototype design includes 32 liquid scintillator detectors with cubic volumes 7.62 cm in dimension configured into 4 stacked rings of 8 detectors. Detector signal collection for the system is handled with a pair of Struck Innovative Systeme 16-channel digitizers controlled by in-house developed software with built-in multiplicity analysis algorithms. Initial testing and familiarization of the currently obtained prototype components is underway, however full prototype construction is required for further optimization. Monte Carlo models of the prototype system were performed to estimate die-away and efficiency values. Analysis of these models resulted in the development of a software package capable of determining the effects of nearest-neighbor rejection methods for elimination of detector cross talk. A parameter study was performed using previously developed analytical methods for the estimation of assay mass variance for use as a figure-of-merit for system performance. A software package was developed to automate these calculations and ensure accuracy. The results of the parameter study show that the prototype fast neutron multiplicity counter design is very nearly optimized under the restraints of the parameter space.

  7. Survivability of systems under multiple factor impact

    Korczak, Edward; Levitin, Gregory

    2007-01-01

    The paper considers vulnerable multi-state series-parallel systems operating under influence of external impacts. Both the external impacts and internal failures affect system survivability, which is determined as the probability of meeting a given demand. The external impacts are characterized by several destructive factors affecting the system or its parts simultaneously. In order to increase the system's survivability a multilevel protection against the destructive factors can be applied to its subsystems. In such systems, the protected subsystems can be destroyed only if all of the levels of their protection are destroyed. The paper presents an algorithm for evaluating the survivability of series-parallel systems with arbitrary configuration of multilevel protection against multiple destructive factor impacts. The algorithm is based on a composition of Boolean and the Universal Generating Function techniques. Illustrative examples are presented

  8. Calcium homeostasis in fly photoreceptor cells

    Oberwinkler, J

    2002-01-01

    In fly photoreceptor cells, two processes dominate the Ca2+ homeostasis: light-induced Ca2+ influx through members of the TRP family of ion channels, and Ca2+ extrusion by Na+/Ca2+ exchange.Ca2+ release from intracellular stores is quantitatively insignificant. Both, the light-activated channels and

  9. Sensorimotor gating deficits in multiple system atrophy

    Zoetmulder, Marielle; Biernat, Heidi Bryde; Nikolic, Miki

    2014-01-01

    Prepulse inhibition (PPI) of the auditory blink reflex is a measure of sensorimotor gating, which reflects an organism's ability to filter out irrelevant sensory information. PPI has never been studied in patients with multiple system atrophy (MSA), although sensorimotor deficits are frequently a...... associated with synucleinopathies. We investigated whether alterations in PPI were more pronounced in MSA compared with Parkinson's disease (PD), idiopathic rapid eye movement sleep behavior disorder (iRBD) and healthy controls....

  10. Stress Effects on Multiple Memory System Interactions

    Ness, Deborah; Calabrese, Pasquale

    2016-01-01

    Extensive behavioural, pharmacological, and neurological research reports stress effects on mammalian memory processes. While stress effects on memory quantity have been known for decades, the influence of stress on multiple memory systems and their distinct contributions to the learning process have only recently been described. In this paper, after summarizing the fundamental biological aspects of stress/emotional arousal and recapitulating functionally and anatomically distinct memory syst...

  11. Optical properties of photoreceptor and retinal pigment epithelium cells investigated with adaptive optics optical coherence tomography

    Liu, Zhuolin

    Human vision starts when photoreceptors collect and respond to light. Photoreceptors do not function in isolation though, but share close interdependence with neighboring photoreceptors and underlying retinal pigment epithelium (RPE) cells. These cellular interactions are essential for normal function of the photoreceptor-RPE complex, but methods to assess these in the living human eye are limited. One approach that has gained increased promise is high-resolution retinal imaging that has undergone tremendous technological advances over the last two decades to probe the living retina at the cellular level. Pivotal in these advances has been adaptive optics (AO) and optical coherence tomography (OCT) that together allow unprecedented spatial resolution of retinal structures in all three dimensions. Using these high-resolution systems, cone photoreceptor are now routinely imaged in healthy and diseased retina enabling fundamental structural properties of cones to be studied such as cell spacing, packing arrangement, and alignment. Other important cell properties, however, have remained elusive to investigation as even better imaging performance is required and thus has resulted in an incomplete understanding of how cells in the photoreceptor-RPE complex interact with light. To address this technical bottleneck, we expanded the imaging capability of AO-OCT to detect and quantify more accurately and completely the optical properties of cone photoreceptor and RPE cells at the cellular level in the living human retina. The first objective of this thesis was development of a new AO-OCT method that is more precise and sensitive, thus enabling a more detailed view of the 3D optical signature of the photoreceptor-RPE complex than was previously possible (Chapter 2). Using this new system, the second objective was quantifying the waveguide properties of individual cone photoreceptor inner and outer segments across the macula (Chapter 3). The third objective extended the AO

  12. Photoreceptor cells with profound structural deficits can support useful vision in mice.

    Thompson, Stewart; Blodi, Frederick R; Lee, Swan; Welder, Chris R; Mullins, Robert F; Tucker, Budd A; Stasheff, Steven F; Stone, Edwin M

    2014-03-25

    In animal models of degenerative photoreceptor disease, there has been some success in restoring photoreception by transplanting stem cell-derived photoreceptor cells into the subretinal space. However, only a small proportion of transplanted cells develop extended outer segments, considered critical for photoreceptor cell function. The purpose of this study was to determine whether photoreceptor cells that lack a fully formed outer segment could usefully contribute to vision. Retinal and visual function was tested in wild-type and Rds mice at 90 days of age (Rds(P90)). Photoreceptor cells of mice homozygous for the Rds mutation in peripherin 2 never develop a fully formed outer segment. The electroretinogram and multielectrode recording of retinal ganglion cells were used to test retinal responses to light. Three distinct visual behaviors were used to assess visual capabilities: the optokinetic tracking response, the discrimination-based visual water task, and a measure of the effect of vision on wheel running. Rds(P90) mice had reduced but measurable electroretinogram responses to light, and exhibited light-evoked responses in multiple types of retinal ganglion cells, the output neurons of the retina. In optokinetic and discrimination-based tests, acuity was measurable but reduced, most notably when contrast was decreased. The wheel running test showed that Rds(P90) mice needed 3 log units brighter luminance than wild type to support useful vision (10 cd/m(2)). Photoreceptors that lack fully formed outer segments can support useful vision. This challenges the idea that normal cellular structure needs to be completely reproduced for transplanted cells to contribute to useful vision.

  13. PAR-Complex and Crumbs Function During Photoreceptor Morphogenesis and Retinal Degeneration.

    Pichaud, Franck

    2018-01-01

    The fly photoreceptor has long been used as a model to study sensory neuron morphogenesis and retinal degeneration. In particular, elucidating how these cells are built continues to help further our understanding of the mechanisms of polarized cell morphogenesis, intracellular trafficking and the causes of human retinal pathologies. The conserved PAR complex, which in flies consists of Cdc42-PAR6-aPKC-Bazooka, and the transmembrane protein Crumbs (Crb) are key players during photoreceptor morphogenesis. While the PAR complex regulates polarity in many cell types, Crb function in polarity is relatively specific to epithelial cells. Together Cdc42-PAR6-aPKC-Bazooka and Crb orchestrate the differentiation of the photoreceptor apical membrane (AM) and zonula adherens (ZA) , thus allowing these cells to assemble into a neuro-epithelial lattice. In addition to its function in epithelial polarity, Crb has also been shown to protect fly photoreceptors from light-induced degeneration, a process linked to Rhodopsin expression and trafficking. Remarkably, mutations in the human Crumbs1 (CRB1) gene lead to retinal degeneration, making the fly photoreceptor a powerful disease model system.

  14. PAR-Complex and Crumbs Function During Photoreceptor Morphogenesis and Retinal Degeneration

    Franck Pichaud

    2018-03-01

    Full Text Available The fly photoreceptor has long been used as a model to study sensory neuron morphogenesis and retinal degeneration. In particular, elucidating how these cells are built continues to help further our understanding of the mechanisms of polarized cell morphogenesis, intracellular trafficking and the causes of human retinal pathologies. The conserved PAR complex, which in flies consists of Cdc42-PAR6-aPKC-Bazooka, and the transmembrane protein Crumbs (Crb are key players during photoreceptor morphogenesis. While the PAR complex regulates polarity in many cell types, Crb function in polarity is relatively specific to epithelial cells. Together Cdc42-PAR6-aPKC-Bazooka and Crb orchestrate the differentiation of the photoreceptor apical membrane (AM and zonula adherens (ZA, thus allowing these cells to assemble into a neuro-epithelial lattice. In addition to its function in epithelial polarity, Crb has also been shown to protect fly photoreceptors from light-induced degeneration, a process linked to Rhodopsin expression and trafficking. Remarkably, mutations in the human Crumbs1 (CRB1 gene lead to retinal degeneration, making the fly photoreceptor a powerful disease model system.

  15. Central nervous system involvement by multiple myeloma

    Jurczyszyn, Artur; Grzasko, Norbert; Gozzetti, Alessandro

    2016-01-01

    The multicenter retrospective study conducted in 38 centers from 20 countries including 172 adult patients with CNS MM aimed to describe the clinical and pathological characteristics and outcomes of patients with multiple myeloma (MM) involving the central nervous system (CNS). Univariate......, 97% patients received initial therapy for CNS disease, of which 76% received systemic therapy, 36% radiotherapy and 32% intrathecal therapy. After a median follow-up of 3.5 years, the median overall survival (OS) from the onset of CNS involvement for the entire group was 7 months. Untreated...... untreated patients and patients with favorable cytogenetic profile might be prolonged due to systemic treatment and/or radiotherapy. This article is protected by copyright. All rights reserved....

  16. Roles of glucose in photoreceptor survival.

    Chertov, Andrei O; Holzhausen, Lars; Kuok, Iok Teng; Couron, Drew; Parker, Ed; Linton, Jonathan D; Sadilek, Martin; Sweet, Ian R; Hurley, James B

    2011-10-07

    Vertebrate photoreceptor neurons have a high demand for metabolic energy, and their viability is very sensitive to genetic and environmental perturbations. We investigated the relationship between energy metabolism and cell death by evaluating the metabolic effects of glucose deprivation on mouse photoreceptors. Oxygen consumption, lactate production, ATP, NADH/NAD(+), TCA cycle intermediates, morphological changes, autophagy, and viability were evaluated. We compared retinas incubated with glucose to retinas deprived of glucose or retinas treated with a mixture of mitochondrion-specific fuels. Rapid and slow phases of cell death were identified. The rapid phase is linked to reduced mitochondrial activity, and the slower phase reflects a need for substrates for cell maintenance and repair.

  17. Response Function of the Crayfish Caudal Photoreceptor to Hydrodynamic Stimuli

    Breite, Sally; Bahar, Sonya; Neiman, Alexander; Moss, Frank

    2002-03-01

    In its abdominal 6th ganglion the crayfish houses 2 light-sensitive neurons (caudal photoreceptors, or CPRs). It is known that these neurons work in tandem with a mechanosensory system of tiny hairs spread across the tailfan, which make synaptic contact with the photoreceptors. A stochastic resonance effect has been shown in this system in which light enhances the transduction of a weak, periodic mechanosensory (hydrodynamic) stimulus. It is not known, however, whether an optimal response from the CPR is induced by a single sine wave cycle or some other waveform. We have experimentally investigated this favorable waveform by driving a tailfan preparation with mechanical 10 Hz correlated Ornstein-Uhlenbeck noise and calculating the response function from the spike-triggered average of the applied noise waveform. We will discuss differences in the shape of the optimal waveform under dark and light conditions, as well as what seems to be a noticeable difference in the magnitude of the animals' response to a noisy stimulus in comparison with a periodic stimulus.

  18. Noninvasive imaging of the human rod photoreceptor mosaic using a confocal adaptive optics scanning ophthalmoscope

    Dubra, Alfredo; Sulai, Yusufu; Norris, Jennifer L.; Cooper, Robert F.; Dubis, Adam M.; Williams, David R.; Carroll, Joseph

    2011-01-01

    The rod photoreceptors are implicated in a number of devastating retinal diseases. However, routine imaging of these cells has remained elusive, even with the advent of adaptive optics imaging. Here, we present the first in vivo images of the contiguous rod photoreceptor mosaic in nine healthy human subjects. The images were collected with three different confocal adaptive optics scanning ophthalmoscopes at two different institutions, using 680 and 775 nm superluminescent diodes for illumination. Estimates of photoreceptor density and rod:cone ratios in the 5°–15° retinal eccentricity range are consistent with histological findings, confirming our ability to resolve the rod mosaic by averaging multiple registered images, without the need for additional image processing. In one subject, we were able to identify the emergence of the first rods at approximately 190 μm from the foveal center, in agreement with previous histological studies. The rod and cone photoreceptor mosaics appear in focus at different retinal depths, with the rod mosaic best focus (i.e., brightest and sharpest) being at least 10 μm shallower than the cones at retinal eccentricities larger than 8°. This study represents an important step in bringing high-resolution imaging to bear on the study of rod disorders. PMID:21750765

  19. Acute Zonal Cone Photoreceptor Outer Segment Loss.

    Aleman, Tomas S; Sandhu, Harpal S; Serrano, Leona W; Traband, Anastasia; Lau, Marisa K; Adamus, Grazyna; Avery, Robert A

    2017-05-01

    The diagnostic path presented narrows down the cause of acute vision loss to the cone photoreceptor outer segment and will refocus the search for the cause of similar currently idiopathic conditions. To describe the structural and functional associations found in a patient with acute zonal occult photoreceptor loss. A case report of an adolescent boy with acute visual field loss despite a normal fundus examination performed at a university teaching hospital. Results of a complete ophthalmic examination, full-field flash electroretinography (ERG) and multifocal ERG, light-adapted achromatic and 2-color dark-adapted perimetry, and microperimetry. Imaging was performed with spectral-domain optical coherence tomography (SD-OCT), near-infrared (NIR) and short-wavelength (SW) fundus autofluorescence (FAF), and NIR reflectance (REF). The patient was evaluated within a week of the onset of a scotoma in the nasal field of his left eye. Visual acuity was 20/20 OU, and color vision was normal in both eyes. Results of the fundus examination and of SW-FAF and NIR-FAF imaging were normal in both eyes, whereas NIR-REF imaging showed a region of hyporeflectance temporal to the fovea that corresponded with a dense relative scotoma noted on light-adapted static perimetry in the left eye. Loss in the photoreceptor outer segment detected by SD-OCT co-localized with an area of dense cone dysfunction detected on light-adapted perimetry and multifocal ERG but with near-normal rod-mediated vision according to results of 2-color dark-adapted perimetry. Full-field flash ERG findings were normal in both eyes. The outer nuclear layer and inner retinal thicknesses were normal. Localized, isolated cone dysfunction may represent the earliest photoreceptor abnormality or a distinct entity within the acute zonal occult outer retinopathy complex. Acute zonal occult outer retinopathy should be considered in patients with acute vision loss and abnormalities on NIR-REF imaging, especially if

  20. Multiple-Active Multiple-Passive Antenna Systems and Applications

    Tsakalaki, Elpiniki

    2013-01-01

    -passive (MAMP) antenna topologies, as explained in Sect. 8.1. Then, Sect. 8.2 proposes MAMP antenna structures with application to reconfigurable MIMO transmission in the presence of antenna mutual coupling under poor scattering channel conditions. For this purpose, the section presents an adaptive MAMP antenna...... system capable of changing its transmission parameters via passive radiators attached to tunable loads, according to the structure of the RF propagation channel. The hybrid MAMP array structure can be tractably analyzed using the active element response vector (instead of the classical steering vector...... adaptive MAMP system can be limited to practical dimensions whereas the passive antennas require no extra RF hardware, thus meeting the cost, space, and power constrains of the users’ mobile terminals. The simulation results show that the adaptive MAMP system, thanks to its “adaptivity”, is able to achieve...

  1. Retinal neuroprotection by hypoxic preconditioning is independent of hypoxia-inducible factor-1 alpha expression in photoreceptors.

    Thiersch, Markus; Lange, Christina; Joly, Sandrine; Heynen, Severin; Le, Yun Zheng; Samardzija, Marijana; Grimm, Christian

    2009-06-01

    Hypoxic preconditioning stabilizes hypoxia-inducible factor (HIF) 1 alpha in the retina and protects photoreceptors against light-induced cell death. HIF-1 alpha is one of the major transcription factors responding to low oxygen tension and can differentially regulate a large number of target genes. To analyse whether photoreceptor-specific expression of HIF-1 alpha is essential to protect photoreceptors by hypoxic preconditioning, we knocked down expression of HIF-1 alpha specifically in photoreceptor cells, using the cyclization recombinase (Cre)-lox system. The Cre-mediated knockdown caused a 20-fold reduced expression of Hif-1 alpha in the photoreceptor cell layer. In the total retina, RNA expression was reduced by 65%, and hypoxic preconditioning led to only a small increase in HIF-1 alpha protein levels. Accordingly, HIF-1 target gene expression after hypoxia was significantly diminished. Retinas of Hif-1 alpha knockdown animals did not show any pathological alterations, and tolerated hypoxic exposure in a comparable way to wild-type retinas. Importantly, the strong neuroprotective effect of hypoxic preconditioning against light-induced photoreceptor degeneration persisted in knockdown mice, suggesting that hypoxia-mediated survival of light exposure does not depend on an autocrine action of HIF-1 alpha in photoreceptor cells. Hypoxia-mediated stabilization of HIF-2 alpha and phosphorylation of signal transducer and activator of transcription 3 (STAT 3) were not affected in the retinas of Hif-1 alpha knockdown mice. Thus, these factors are candidates for regulating the resistance of photoreceptors to light damage after hypoxic preconditioning, along with several potentially neuroprotective genes that were similarly induced in hypoxic knockdown and control mice.

  2. The massive multiple system HD 64315

    Lorenzo, J.; Simón-Díaz, S.; Negueruela, I.; Vilardell, F.; Garcia, M.; Evans, C. J.; Montes, D.

    2017-10-01

    Context. The O6 Vn star HD 64315 is believed to belong to the star-forming region known as NGC 2467, but previous distance estimates do not support this association. Moreover, it has been identified as a spectroscopic binary, but existing data support contradictory values for its orbital period. Aims: We explore the multiple nature of this star with the aim of determining its distance, and understanding its connection to NGC 2467. Methods: A total of 52 high-resolution spectra have been gathered over a decade. We use their analysis, in combination with the photometric data from All Sky Automated Survey and Hipparcos catalogues, to conclude that HD 64315 is composed of at least two spectroscopic binaries, one of which is an eclipsing binary. We have developed our own program to fit four components to the combined line shapes. Once the four radial velocities were derived, we obtained a model to fit the radial-velocity curves using the Spectroscopic Binary Orbit Program (SBOP). We then implemented the radial velocities of the eclipsing binary and the light curves in the Wilson-Devinney code iteratively to derive stellar parameters for its components. We were also able to analyse the non-eclipsing binary, and to derive minimum masses for its components which dominate the system flux. Results: HD 64315 contains two binary systems, one of which is an eclipsing binary. The two binaries are separated by 0.09 arcsec (or 500 AU) if the most likely distance to the system, 5 kpc, is considered. The presence of fainter companions is not excluded by current observations. The non-eclipsing binary (HD 64315 AaAb) has a period of 2.70962901 ± 0.00000021 d. Its components are hotter than those of the eclipsing binary, and dominate the appearance of the system. The eclipsing binary (HD 64315 BaBb) has a shorter period of 1.0189569 ± 0.0000008 d. We derive masses of 14.6 ± 2.3 M⊙ for both components of the BaBb system. They are almost identical; both stars are overfilling their

  3. On the performance of spectrum sharing systems with multiple antennas

    Yang, Liang; Alouini, Mohamed-Slim; Qaraqe, Khalid A.

    2012-01-01

    In this paper, we study the capacity of spectrum sharing (SS) multiple-input multiple-output (MIMO) systems over Rayleigh fading channels. More specifically, we present closed-form capacity formulas for such systems with and without optimal power

  4. Fluid biomarkers in multiple system atrophy

    Laurens, Brice; Constantinescu, Radu; Freeman, Roy

    2015-01-01

    Despite growing research efforts, no reliable biomarker currently exists for the diagnosis and prognosis of multiple system atrophy (MSA). Such biomarkers are urgently needed to improve diagnostic accuracy, prognostic guidance and also to serve as efficacy measures or surrogates of target...... engagement for future clinical trials. We here review candidate fluid biomarkers for MSA and provide considerations for further developments and harmonization of standard operating procedures. A PubMed search was performed until April 24, 2015 to review the literature with regard to candidate blood...... and cerebrospinal fluid (CSF) biomarkers for MSA. Abstracts of 1760 studies were retrieved and screened for eligibility. The final list included 60 studies assessing fluid biomarkers in patients with MSA. Most studies have focused on alpha-synuclein, markers of axonal degeneration or catecholamines. Their results...

  5. Derivation of human differential photoreceptor-like cells from the iris by defined combinations of CRX, RX and NEUROD.

    Yuko Seko

    Full Text Available Examples of direct differentiation by defined transcription factors have been provided for beta-cells, cardiomyocytes and neurons. In the human visual system, there are four kinds of photoreceptors in the retina. Neural retina and iris-pigmented epithelium (IPE share a common developmental origin, leading us to test whether human iris cells could differentiate to retinal neurons. We here define the transcription factor combinations that can determine human photoreceptor cell fate. Expression of rhodopsin, blue opsin and green/red opsin in induced photoreceptor cells were dependent on combinations of transcription factors: A combination of CRX and NEUROD induced rhodopsin and blue opsin, but did not induce green opsin; a combination of CRX and RX induced blue opsin and green/red opsin, but did not induce rhodopsin. Phototransduction-related genes as well as opsin genes were up-regulated in those cells. Functional analysis; i.e. patch clamp recordings, clearly revealed that generated photoreceptor cells, induced by CRX, RX and NEUROD, responded to light. The response was an inward current instead of the typical outward current. These data suggest that photosensitive photoreceptor cells can be generated by combinations of transcription factors. The combination of CRX and RX generate immature photoreceptors: and additional NEUROD promotes maturation. These findings contribute substantially to a major advance toward eventual cell-based therapy for retinal degenerative diseases.

  6. Multiple systems for motor skill learning.

    Clark, Dav; Ivry, Richard B

    2010-07-01

    Motor learning is a ubiquitous feature of human competence. This review focuses on two particular classes of model tasks for studying skill acquisition. The serial reaction time (SRT) task is used to probe how people learn sequences of actions, while adaptation in the context of visuomotor or force field perturbations serves to illustrate how preexisting movements are recalibrated in novel environments. These tasks highlight important issues regarding the representational changes that occur during the course of motor learning. One important theme is that distinct mechanisms vary in their information processing costs during learning and performance. Fast learning processes may require few trials to produce large changes in performance but impose demands on cognitive resources. Slower processes are limited in their ability to integrate complex information but minimally demanding in terms of attention or processing resources. The representations derived from fast systems may be accessible to conscious processing and provide a relatively greater measure of flexibility, while the representations derived from slower systems are more inflexible and automatic in their behavior. In exploring these issues, we focus on how multiple neural systems may interact and compete during the acquisition and consolidation of new behaviors. Copyright © 2010 John Wiley & Sons, Ltd. This article is categorized under: Psychology > Motor Skill and Performance. Copyright © 2010 John Wiley & Sons, Ltd.

  7. Quantized levitation states of superconducting multiple-ring systems

    Haley, S.B.; Fink, H.J.

    1996-01-01

    The quantized levitation, trapped, and suspension states of a magnetic microsphere held in equilibrium by two fixed superconducting (SC) microrings are calculated by minimizing the free energy of the system. Each state is a discrete function of two independent fluxoid quantum numbers of the rings. When the radii of the SC rings are of the same order as the Ginzburg-Landau coherence length ξ(T), the system exhibits a small set of gravity and temperature-dependent levels. The levels of a weakly magnetized particle are sensitive functions of the gravitational field, indicating potential application as an accelerometer, and for trapping small magnetic particles in outer space or on Earth. The equilibrium states of a SC ring levitated by another SC ring are also calculated. copyright 1996 The American Physical Society

  8. Simple explant culture of the embryonic chicken retina with long-term preservation of photoreceptors.

    Thangaraj, Gopenath; Greif, Alexander; Layer, Paul G

    2011-10-01

    Structurally stable in vitro-model systems are indispensible to analyse neural development during embryogenesis, follow cellular differentiation and evaluate neurotoxicological or growth factor effects. Here we describe a three-dimensional, long-term in vitro-culture system of the embryonic chick retina which supports photoreceptor development. Retinal tissue was isolated from E6 chick eye, and cultured as explants by continuous orbital rotation to allow free floatation without any supporting materials. Young stage (E6) immature retinas were cultured for various time periods in order to follow the differentiation of cell types and plexiform layers by immunocytochemical methods. These explants could be cultured for at least 2-3 weeks with remarkable retention of retinal architecture. Interestingly, photoreceptors developed in the absence of pigment epithelium. Electron microscopic studies revealed formation of structures resembling photoreceptor outer segments, a feature not reported previously. Thus, the verification of photoreceptors, Müller cells, inner retinal cells and the inner plexiform layer described in our study establishes this explant culture as a valuable in vivo-like model system. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

  9. Automated Photoreceptor Cell Identification on Nonconfocal Adaptive Optics Images Using Multiscale Circular Voting.

    Liu, Jianfei; Jung, HaeWon; Dubra, Alfredo; Tam, Johnny

    2017-09-01

    Adaptive optics scanning light ophthalmoscopy (AOSLO) has enabled quantification of the photoreceptor mosaic in the living human eye using metrics such as cell density and average spacing. These rely on the identification of individual cells. Here, we demonstrate a novel approach for computer-aided identification of cone photoreceptors on nonconfocal split detection AOSLO images. Algorithms for identification of cone photoreceptors were developed, based on multiscale circular voting (MSCV) in combination with a priori knowledge that split detection images resemble Nomarski differential interference contrast images, in which dark and bright regions are present on the two sides of each cell. The proposed algorithm locates dark and bright region pairs, iteratively refining the identification across multiple scales. Identification accuracy was assessed in data from 10 subjects by comparing automated identifications with manual labeling, followed by computation of density and spacing metrics for comparison to histology and published data. There was good agreement between manual and automated cone identifications with overall recall, precision, and F1 score of 92.9%, 90.8%, and 91.8%, respectively. On average, computed density and spacing values using automated identification were within 10.7% and 11.2% of the expected histology values across eccentricities ranging from 0.5 to 6.2 mm. There was no statistically significant difference between MSCV-based and histology-based density measurements (P = 0.96, Kolmogorov-Smirnov 2-sample test). MSCV can accurately detect cone photoreceptors on split detection images across a range of eccentricities, enabling quick, objective estimation of photoreceptor mosaic metrics, which will be important for future clinical trials utilizing adaptive optics.

  10. Multimodal Imaging of Photoreceptor Structure in Choroideremia.

    Sun, Lynn W; Johnson, Ryan D; Williams, Vesper; Summerfelt, Phyllis; Dubra, Alfredo; Weinberg, David V; Stepien, Kimberly E; Fishman, Gerald A; Carroll, Joseph

    2016-01-01

    Choroideremia is a progressive X-linked recessive dystrophy, characterized by degeneration of the retinal pigment epithelium (RPE), choroid, choriocapillaris, and photoreceptors. We examined photoreceptor structure in a series of subjects with choroideremia with particular attention to areas bordering atrophic lesions. Twelve males with clinically-diagnosed choroideremia and confirmed hemizygous mutations in the CHM gene were examined. High-resolution images of the retina were obtained using spectral domain optical coherence tomography (SD-OCT) and both confocal and non-confocal split-detector adaptive optics scanning light ophthalmoscope (AOSLO) techniques. Eleven CHM gene mutations (3 novel) were identified; three subjects had the same mutation and one subject had two mutations. SD-OCT findings included interdigitation zone (IZ) attenuation or loss in 10/12 subjects, often in areas with intact ellipsoid zones; RPE thinning in all subjects; interlaminar bridges in the imaged areas of 10/12 subjects; and outer retinal tubulations (ORTs) in 10/12 subjects. Only split-detector AOSLO could reliably resolve cones near lesion borders, and such cones were abnormally heterogeneous in morphology, diameter and density. On split-detector imaging, the cone mosaic terminated sharply at lesion borders in 5/5 cases examined. Split-detector imaging detected remnant cone inner segments within ORTs, which were generally contiguous with a central patch of preserved retina. Early IZ dropout and RPE thinning on SD-OCT are consistent with previously published results. Evidence of remnant cone inner segments within ORTs and the continuity of the ORTs with preserved retina suggests that these may represent an intermediate state of retinal degeneration prior to complete atrophy. Taken together, these results supports a model of choroideremia in which the RPE degenerates before photoreceptors.

  11. Depression and anxiety in multiple system atrophy.

    Zhang, L-Y; Cao, B; Zou, Y-T; Wei, Q-Q; Ou, R-W; Zhao, B; Wu, Y; Shang, H-F

    2018-01-01

    It has been noticed that the patients with multiple system atrophy (MSA) can accompany with depression and anxiety. This study aimed to establish the incidence and determinants of depression and anxiety symptoms in Chinese MSA patients. A total of 237 MSA patients were enrolled in the study. Neuropsychological assessment was performed using Hamilton Depression Rating Scale-24 items and Hamilton Anxiety Rating Scale. We found that 62.0% and 71.7% patients had at least mild depression and anxiety symptoms, respectively. The severity of depression of MSA patients was associated with lower educational years (P=.024), longer disease duration (Panxiety was associated with increased disease duration (Panxiety were female gender, longer disease duration, and disease severity. Depression and anxiety symptoms are common in patients with MSA. Neurologists should pay attention to depression and anxiety in patients with MSA, especially in female patients and those with longer disease duration and severe disease condition. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. System for Collecting Biosignal Data from Multiple Patient Monitoring Systems.

    Yoon, Dukyong; Lee, Sukhoon; Kim, Tae Young; Ko, JeongGil; Chung, Wou Young; Park, Rae Woong

    2017-10-01

    Biosignal data include important physiological information. For that reason, many devices and systems have been developed, but there has not been enough consideration of how to collect and integrate raw data from multiple systems. To overcome this limitation, we have developed a system for collecting and integrating biosignal data from two patient monitoring systems. We developed an interface to extract biosignal data from Nihon Kohden and Philips monitoring systems. The Nihon Kohden system has a central server for the temporary storage of raw waveform data, which can be requested using the HL7 protocol. However, the Philips system used in our hospital cannot save raw waveform data. Therefore, our system was connected to monitoring devices using the RS232 protocol. After collection, the data were transformed and stored in a unified format. From September 2016 to August 2017, we collected approximately 117 patient-years of waveform data from 1,268 patients in 79 beds of five intensive care units. Because the two systems use the same data storage format, the application software could be run without compatibility issues. Our system collects biosignal data from different systems in a unified format. The data collected by the system can be used to develop algorithms or applications without the need to consider the source of the data.

  13. Fast modified signal-digit (MSD) multiplication technology and system

    Sun, DeGui; He, Li-Ming; Wang, Na-Xin; Weng, Zhao-Heng

    1994-06-01

    In this paper, the carry-free property of modified-signed-digit (MSD) addition is analyzed with a space position logic encoding scheme. On this basis, MSD multiplication is discussed and a fast MSD multiplication system composed of optoelectronic logic technology and a multilayer optical interconnection architecture is propsed and studied. Finally, the effectivity of the fast MSD multiplication system is demostrated by using a 2X2 bit multiplication example and experimental results are given.

  14. Linear systems and multiplicity of ideals

    Le Dung Trang

    2008-06-01

    Using a geometric interpretation of the multiplicity, we give a geometric way to calculate the multiplicity. We consider the particular case of a non-singular complex surface and give an example with a geometric proof of a result. Most of this note is written in the language of complex analytic spaces, but the results can be stated and proved in the case of schemes of finite type over an infinite field with equi-characteristic local rings

  15. Bifurcation analysis of a photoreceptor interaction model for Retinitis Pigmentosa

    Camacho, Erika T.; Radulescu, Anca; Wirkus, Stephen

    2016-09-01

    Retinitis Pigmentosa (RP) is the term used to describe a diverse set of degenerative eye diseases affecting the photoreceptors (rods and cones) in the retina. This work builds on an existing mathematical model of RP that focused on the interaction of the rods and cones. We non-dimensionalize the model and examine the stability of the equilibria. We then numerically investigate other stable modes that are present in the system for various parameter values and relate these modes to the original problem. Our results show that stable modes exist for a wider range of parameter values than the stability of the equilibrium solutions alone, suggesting that additional approaches to preventing cone death may exist.

  16. Shifts in Selective Pressures on Snake Phototransduction Genes Associated with Photoreceptor Transmutation and Dim-Light Ancestry.

    Schott, Ryan K; Van Nynatten, Alexander; Card, Daren C; Castoe, Todd A; S W Chang, Belinda

    2018-06-01

    The visual systems of snakes are heavily modified relative to other squamates, a condition often thought to reflect their fossorial origins. Further modifications are seen in caenophidian snakes, where evolutionary transitions between rod and cone photoreceptors, termed photoreceptor transmutations, have occurred in many lineages. Little previous work, however, has focused on the molecular evolutionary underpinnings of these morphological changes. To address this, we sequenced seven snake eye transcriptomes and utilized new whole-genome and targeted capture sequencing data. We used these data to analyze gene loss and shifts in selection pressures in phototransduction genes that may be associated with snake evolutionary origins and photoreceptor transmutation. We identified the surprising loss of rhodopsin kinase (GRK1), despite a low degree of gene loss overall and a lack of relaxed selection early during snake evolution. These results provide some of the first evolutionary genomic corroboration for a dim-light ancestor that lacks strong fossorial adaptations. Our results also indicate that snakes with photoreceptor transmutation experienced significantly different selection pressures from other reptiles. Significant positive selection was found primarily in cone-specific genes, but not rod-specific genes, contrary to our expectations. These results reveal potential molecular adaptations associated with photoreceptor transmutation and also highlight unappreciated functional differences between rod- and cone-specific phototransduction proteins. This intriguing example of snake visual system evolution illustrates how the underlying molecular components of a complex system can be reshaped in response to changing selection pressures.

  17. Relative null controllability of linear systems with multiple delays in ...

    varying multiple delays in state and control are developed. If the uncontrolled system is uniformly asymptotically stable, and if the linear system is controllable, then the linear system is null controllable. Journal of the Nigerian Association of ...

  18. Magnetic resonance imaging in multiple system atrophy

    Aotsuka, Akiyo; Shinotoh, Hitoshi; Hirayama, Keizo [Chiba Univ. (Japan). School of Medicine; Ikehira, Hiroo; Hashimoto, Takahiro

    1992-08-01

    We studied 18 patients with multiple system atrophy (MSA) by high field strength MRI: 6 striatonigral degeneration (SND), 4 Shy-Drager syndrome (SDS), and 8 olivo-ponto-cerebellar atrophy (OPCA). We also studied 30 Parkinson's disease (PD) and 10 age-matched controls. The diagnosis of SND, SDS, and OPCA were based on criteria after Hirayama et al (1985). Bradykinesia, rigidity, and tremor were assessed with the summed scores of the signs used as the extrapyramidal scores. The mean extrapyramidal scores were not significantly different in patients with SND, SDS, OPCA, and PD. MRI studies were performed on 1.5 tesla MRI unit, using a T[sub 2]-weighted spin echo pulse sequence (TR2500 ms/TE40 ms). The width of the pars compacta signal in all subjects was measured by the method of Duguid et al (1986). Intensity profiles were made on a straight line perpendicular to the pars compacta through the center of the red nucleus on an image of the midbrain. We measured the width of the valley at half-height between the peaks of an index of the width of the pars compacta signal. The mean widths of the pars compacta signal were: 2.8[+-]0.4 mm (SND), 2.8[+-]0.7 mm (SDS), 3.6[+-]0.6 mm (OPCA), 2.7[+-]0.3 mm (PD), and 4.3[+-]0.6 mm (control). The mean widths of the pars compacta signal in PD, SND, and SDS were significantly narrower than that in the control group (p<0.05), while the OPCA group was not significantly narrower. The results may indicate that the time course of nigral involvement is milder in OPCA than in SND and SDS. The extrapyramidal signs in OPCA may be attributed mainly to the degeneration of the putamen rather than to that of the substantia nigra. Abnormal hypointensity in the posterolateral putamen was found in only one SND patient and in two OPCA patients, even though this finding has been frequently observed in MSA. Since no PD patients exhibited this finding, it may of some value in differentiating MSA from PD. (author).

  19. Multiple operating system rotation environment moving target defense

    Evans, Nathaniel; Thompson, Michael

    2016-03-22

    Systems and methods for providing a multiple operating system rotation environment ("MORE") moving target defense ("MTD") computing system are described. The MORE-MTD system provides enhanced computer system security through a rotation of multiple operating systems. The MORE-MTD system increases attacker uncertainty, increases the cost of attacking the system, reduces the likelihood of an attacker locating a vulnerability, and reduces the exposure time of any located vulnerability. The MORE-MTD environment is effectuated by rotation of the operating systems at a given interval. The rotating operating systems create a consistently changing attack surface for remote attackers.

  20. Abnormal pain perception in patients with Multiple System Atrophy.

    Ory-Magne, F; Pellaprat, J; Harroch, E; Galitzsky, M; Rousseau, V; Pavy-Le Traon, A; Rascol, O; Gerdelat, A; Brefel-Courbon, C

    2018-03-01

    Patients with Parkinson's disease or Multiple System Atrophy frequently experience painful sensations. The few studies investigating pain mechanisms in Multiple System Atrophy patients have reported contradictory results. In our study, we compared pain thresholds in Multiple System Atrophy and Parkinson's disease patients and healthy controls and evaluated the effect of l-DOPA on pain thresholds. We assessed subjective and objective pain thresholds (using a thermotest and RIII reflex), and pain tolerance in OFF and ON conditions, clinical pain, motor and psychological evaluation. Pain was reported in 78.6% of Multiple System Atrophy patients and in 37.5% of Parkinson's disease patients. In the OFF condition, subjective and objective pain thresholds were significantly lower in Multiple System Atrophy patients than in healthy controls (43.8 °C ± 1.3 vs 45.7 °C ± 0.8; p = 0.0005 and 7.4 mA ± 3.8 vs 13.7 mA ± 2.8; p = 0.002, respectively). They were also significantly reduced in Multiple System Atrophy compared to Parkinson's disease patients. No significant difference was found in pain tolerance for the 3 groups and in the effect of l-DOPA on pain thresholds in Multiple System Atrophy and Parkinson's disease patients. In the ON condition, pain tolerance tended to be reduced in Multiple System Atrophy versus Parkinson's disease patients (p = 0.05). Multiple System Atrophy patients had an increase in pain perception compared to Parkinson's disease patients and healthy controls. The l-DOPA effect was similar for pain thresholds in Multiple System Atrophy and Parkinson's disease patients, but tended to worsen pain tolerance in Multiple System Atrophy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Supervising System Stress in Multiple Markets

    Mikhail V. Oet

    2015-09-01

    Full Text Available This paper develops an extended financial stress measure that considers the supervisory objective of identifying risks to the stability of the financial system. The measure provides a continuous and bounded signal of financial stress using daily public market data. Broad coverage of material financial system markets over time is achieved by leveraging dynamic credit weights. We consider how this measure can be used to monitor, analyze, and alert financial system stress.

  2. Random Photon Absorption Model Elucidates How Early Gain Control in Fly Photoreceptors Arises from Quantal Sampling

    Song, Zhuoyi; Zhou, Yu; Juusola, Mikko

    2016-01-01

    Many diurnal photoreceptors encode vast real-world light changes effectively, but how this performance originates from photon sampling is unclear. A 4-module biophysically-realistic fly photoreceptor model, in which information capture is limited by the number of its sampling units (microvilli) and their photon-hit recovery time (refractoriness), can accurately simulate real recordings and their information content. However, sublinear summation in quantum bump production (quantum-gain-nonlinearity) may also cause adaptation by reducing the bump/photon gain when multiple photons hit the same microvillus simultaneously. Here, we use a Random Photon Absorption Model (RandPAM), which is the 1st module of the 4-module fly photoreceptor model, to quantify the contribution of quantum-gain-nonlinearity in light adaptation. We show how quantum-gain-nonlinearity already results from photon sampling alone. In the extreme case, when two or more simultaneous photon-hits reduce to a single sublinear value, quantum-gain-nonlinearity is preset before the phototransduction reactions adapt the quantum bump waveform. However, the contribution of quantum-gain-nonlinearity in light adaptation depends upon the likelihood of multi-photon-hits, which is strictly determined by the number of microvilli and light intensity. Specifically, its contribution to light-adaptation is marginal (≤ 1%) in fly photoreceptors with many thousands of microvilli, because the probability of simultaneous multi-photon-hits on any one microvillus is low even during daylight conditions. However, in cells with fewer sampling units, the impact of quantum-gain-nonlinearity increases with brightening light. PMID:27445779

  3. NADPH Oxidase Contributes to Photoreceptor Degeneration in Constitutively Active RAC1 Mice

    Song, Hongman; Vijayasarathy, Camasamudram; Zeng, Yong; Marangoni, Dario; Bush, Ronald A.; Wu, Zhijian; Sieving, Paul A.

    2016-01-01

    Purpose The active form of small GTPase RAC1 is required for activation of NADPH oxidase (NOX), which in turn generates reactive oxygen species (ROS) in nonphagocytic cells. We explored whether NOX-induced oxidative stress contributes to rod degeneration in retinas expressing constitutively active (CA) RAC1. Methods Transgenic (Tg)–CA-RAC1 mice were given apocynin (10 mg/kg, intraperitoneal), a NOX inhibitor, or vehicle daily for up to 13 weeks. Superoxide production and oxidative damage were assessed by dihydroethidium staining and by protein carbonyls and malondialdehyde levels, respectively. Outer nuclear layer (ONL) cells were counted and electroretinogram (ERG) amplitudes measured in Tg-CA-RAC1 mice. Outer nuclear layer cells were counted in wild-type (WT) mice after transfer of CA-Rac1 gene by subretinal injection of AAV8-pOpsin-CA Rac1-GFP. Results Transgenic-CA-RAC1 retinas had significantly fewer photoreceptor cells and more apoptotic ONL cells than WT controls from postnatal week (Pw) 3 to Pw13. Superoxide accumulation and protein and lipid oxidation were increased in Tg-CA-RAC1 retinas and were reduced in mice treated with apocynin. Apocynin reduced the loss of photoreceptors and increased the rod ERG a- and b-wave amplitudes when compared with vehicle-injected transgenic controls. Photoreceptor loss was also observed in regions of adult WT retina transduced with AAV8-pOpsin-CA Rac1-GFP but not in neighboring regions that were not transduced or in AAV8-pOpsin-GFP–transduced retinas. Conclusions Constitutively active RAC1 promotes photoreceptor cell death by oxidative damage that occurs, at least partially, through NOX-induced ROS. Reactive oxygen species are likely involved in multiple forms of retinal degenerations, and our results support investigating RAC1 inhibition as a therapeutic approach that targets this disease pathway. PMID:27233035

  4. Multiple system modelling of waste management

    Eriksson, Ola; Bisaillon, Mattias

    2011-01-01

    Highlights: → Linking of models will provide a more complete, correct and credible picture of the systems. → The linking procedure is easy to perform and also leads to activation of project partners. → The simulation procedure is a bit more complicated and calls for the ability to run both models. - Abstract: Due to increased environmental awareness, planning and performance of waste management has become more and more complex. Therefore waste management has early been subject to different types of modelling. Another field with long experience of modelling and systems perspective is energy systems. The two modelling traditions have developed side by side, but so far there are very few attempts to combine them. Waste management systems can be linked together with energy systems through incineration plants. The models for waste management can be modelled on a quite detailed level whereas surrounding systems are modelled in a more simplistic way. This is a problem, as previous studies have shown that assumptions on the surrounding system often tend to be important for the conclusions. In this paper it is shown how two models, one for the district heating system (MARTES) and another one for the waste management system (ORWARE), can be linked together. The strengths and weaknesses with model linking are discussed when compared to simplistic assumptions on effects in the energy and waste management systems. It is concluded that the linking of models will provide a more complete, correct and credible picture of the consequences of different simultaneous changes in the systems. The linking procedure is easy to perform and also leads to activation of project partners. However, the simulation procedure is a bit more complicated and calls for the ability to run both models.

  5. Production System Design for Multiple Brands

    Karlsson, Christer; Christensen, Irene

    Production systems enabling both cost efficiency and flexibility in terms of high product variation are explored. The study follows an explorative longitudinal field study approach. The database consists of three large global corporations, each consisting of several companies producing household ......-outs, worker skills, integration of distribution channels, after sales service and degree of servitization. Three production system design principles called VXY emerge....

  6. Identification of endogenous fluorophores in the photoreceptors using autofluorescence spectroscopy

    Zhao, Lingling; Qu, Junle; Niu, Hanben

    2007-11-01

    In this paper, we present our investigation on the identification of endogenous fluorophores in photoreceptors using autofluorescence spectroscopy, which is performed with an inverted laser scanning confocal microscope equipped with an Argon ion laser and a GreNe laser. In our experiments, individual cones and rods are clearly resolved even in freshly prepared retina samples, without slicing or labeling. The experiment results show that autofluorescence spectrum of the photoreceptors has three peaks approximately at 525nm, 585nm and 665nm. Furthermore, the brightest autofluorescence originates from the photoreceptor outer segments. We can, therefore, come to a conclusion that the peaks at 525nm, 585nm are corresponding to FAD and A2-PE, respectively, which are distributed in the photoreceptor outer segments.

  7. Extracellular electrical activity from the photoreceptors of midge

    Unknown

    349. Keywords. Chironomus; electroretinogram; insect development; midge; photoreceptor ... ceran insects, only larval ocelli of mosquito (Family: Culi- cidae) have been ... and Ball (1995) studied the influence of light in Chiro- nomus tentans ...

  8. [Modification of retinal photoreceptor membranes and Ca ion binding].

    Korchagin, V P; Berman, A L; Shukoliukov, S A; Rychkova, M P; Etingof, R N

    1978-10-01

    Calcium binding by modified photoreceptor membranes of cattle retina has been studied. Ca2+-binding the membranes significantly changes after C-phospholipase treatment, displaying the initial growth (less than 65% of lipid phosphorus removed) with subsequent decrease (more than 65% of phosphorus removed). Liposomes of the photoreceptor membranes lipids were found to bind more calcium than do the native photoreceptor membranes. Proteolytic enzymes (papaine, pronase) splitting some rhodopsin fragments do not affect the ability of the membrane to bind Ca2+. The increase of light-induced Ca-binding is observed only after the outer segments preincubation under conditions providing for rhodopsin phosphorylation. This effect was observed also after the splitting of the rhodopsin fragment by papaine. It is concluded that calcium binding in the photoreceptor membranes is mainly due to the phosphate groups of phospholipids.

  9. Supporting multiple control systems at Fermilab

    Nicklaus, Dennis J.; /Fermilab

    2009-10-01

    The Fermilab control system, ACNET, is used for controlling the Tevatron and all of its pre-accelerators. However, other smaller experiments at Fermilab have been using different controls systems, in particular DOOCS and EPICS. This paper reports some of the steps taken at Fermilab to integrate support for these outside systems. We will describe specific tools that we have built or adapted to facilitate interaction between the architectures. We also examine some of the difficulties that arise from managing this heterogeneous environment. Incompatibilities as well as common elements will be described.

  10. Photoreceptor atrophy in acute zonal occult outer retinopathy

    Zibrandtsen, N.; Munch, I.C.; Klemp, K.

    2008-01-01

    appearance were examined using optical coherence tomography (OCT), automated perimetry and electroretinography (ERG). RESULTS: Both patients demonstrated photoreceptor atrophy corresponding to partial or complete scotomata with reduced or extinct electroretinographic responses. Attenuation or complete loss...... of all the segments composing the photoreceptor layer was found by OCT. Full-field ERG revealed affection of the 30 Hz flicker responses and subnormal photopic responses in both patients and subnormal scotopic responses in case 1. Multifocal electroretinography (mERG) revealed localized outer retinal...

  11. Photoreceptor atrophy in acute zonal occult outer retinopathy

    Zibrandtsen, N.; Munch, I.C.; Klemp, K.

    2008-01-01

    examined using optical coherence tomography (OCT), automated perimetry and electroretinography (ERG). Both patients demonstrated photoreceptor atrophy corresponding to partial or complete scotomata with reduced or extinct electroretinographic responses. Attenuation or complete loss of all the segments...... composing the photoreceptor layer was found by OCT. Full-field ERG revealed affection of the 30 Hz flicker responses and subnormal photopic responses in both patients and subnormal scotopic responses in case 1. Multifocal electroretinography (mERG) revealed localized outer retinal dysfunction. The field...

  12. Photoreceptor layer map using spectral-domain optical coherence tomography.

    Lee, Ji Eun; Lim, Dae Won; Bae, Han Yong; Park, Hyun Jin

    2009-12-01

    To develop a novel method for analysis of the photoreceptor layer map (PLM) generated using spectral-domain optical coherence tomography (OCT). OCT scans were obtained from 20 eyes, 10 with macular holes (MH) and 10 with central serous chorioretinopathy (CSC) using the Macular Cube (512 x 128) protocol of the Cirrus HD-OCT (Carl Zeiss). The scanned data were processed using embedded tools of the advanced visualization. A partial thickness OCT fundus image of the photoreceptor layer was generated by setting the region of interest to a 50-microm thick layer that was parallel and adjacent to the retinal pigment epithelium. The resulting image depicted the photoreceptor layer as a map of the reflectivity in OCT. The PLM was compared with fundus photography, auto-fluorescence, tomography, and retinal thickness map. The signal from the photoreceptor layer of every OCT scan in each case was demonstrated as a single image of PLM in a fundus photograph fashion. In PLM images, detachment of the sensory retina is depicted as a hypo-reflective area, which represents the base of MH and serous detachment in CSC. Relative hypo-reflectivity, which was also noted at closed MH and at recently reattached retina in CSC, was associated with reduced signal from the junction between the inner and outer segments of photoreceptors in OCT images. Using PLM, changes in the area of detachment and reflectivity of the photoreceptor layer could be efficiently monitored. The photoreceptor layer can be analyzed as a map using spectral-domain OCT. In the treatment of both MH and CSC, PLM may provide new pathological information about the photoreceptor layer to expand our understanding of these diseases.

  13. Managers’ Use of Multiple Management Control Systems

    Willert, Jeanette

    This dissertation addresses the topic Management Control Systems (MCS) as a Package. Many research studies investigate management and control systems individually, whereas fewer research studies take a holistic view and include a larger part of all the MCS managers use to guide and direct...... subordinates behaviour in the best interest of their companies. In the MCS literature, it is stressed that knowledge is particularly lacking about how managers design and use MCS as a package, and the effectiveness of using the MCS. This dissertation responds to this call by carrying out a large survey among...... executive managers in large companies, a survey that investigates the subject: Effective Management and Control Systems. The focus in the survey is to explore how executive management in large companies design and use their management control systems package. Further, this study is supplemented...

  14. Multiple equilibria in a simple elastocapillary system

    Taroni, Michele; Vella, Dominic

    2012-01-01

    properties two stable equilibria may exist, and show via numerical solutions of the dynamic model that it is the initial state of the system that determines which stable equilibrium is ultimately reached. © 2012 Cambridge University Press.

  15. Multiple Drosophila Tracking System with Heading Direction

    Pudith Sirigrivatanawong

    2017-01-01

    Full Text Available Machine vision systems have been widely used for image analysis, especially that which is beyond human ability. In biology, studies of behavior help scientists to understand the relationship between sensory stimuli and animal responses. This typically requires the analysis and quantification of animal locomotion. In our work, we focus on the analysis of the locomotion of the fruit fly D r o s o p h i l a m e l a n o g a s t e r , a widely used model organism in biological research. Our system consists of two components: fly detection and tracking. Our system provides the ability to extract a group of flies as the objects of concern and furthermore determines the heading direction of each fly. As each fly moves, the system states are refined with a Kalman filter to obtain the optimal estimation. For the tracking step, combining information such as position and heading direction with assignment algorithms gives a successful tracking result. The use of heading direction increases the system efficiency when dealing with identity loss and flies swapping situations. The system can also operate with a variety of videos with different light intensities.

  16. System for prediction and determination of the sub critic multiplication

    Martinez, Aquilino S.; Pereira, Valmir; Silva, Fernando C. da

    1997-01-01

    It is presented a concept of a system which may be used to calculate and anticipate the subcritical multiplication of a PWR nuclear power plant. The system is divided into two different modules. The first module allows the theoretical prediction of the subcritical multiplication factor through the solution of the multigroup diffusion equation. The second module determines this factor based on the data acquired from the neutron detectors of a NPP external nuclear detection system. (author). 3 refs., 3 figs., 2 tabs

  17. Genetic Dissection of Dual Roles for the Transcription Factor six7 in Photoreceptor Development and Patterning in Zebrafish.

    Mailin Sotolongo-Lopez

    2016-04-01

    Full Text Available The visual system of a particular species is highly adapted to convey detailed ecological and behavioral information essential for survival. The consequences of structural mutations of opsins upon spectral sensitivity and environmental adaptation have been studied in great detail, but lacking is knowledge of the potential influence of alterations in gene regulatory networks upon the diversity of cone subtypes and the variation in the ratio of rods and cones observed in numerous diurnal and nocturnal species. Exploiting photoreceptor patterning in cone-dominated zebrafish, we uncovered two independent mechanisms by which the sine oculis homeobox homolog 7 (six7 regulates photoreceptor development. In a genetic screen, we isolated the lots-of-rods-junior (ljrp23ahub mutation that resulted in an increased number and uniform distribution of rods in otherwise normal appearing larvae. Sequence analysis, genome editing using TALENs and knockdown strategies confirm ljrp23ahub as a hypomorphic allele of six7, a teleost orthologue of six3, with known roles in forebrain patterning and expression of opsins. Based on the lack of predicted protein-coding changes and a deletion of a conserved element upstream of the transcription start site, a cis-regulatory mutation is proposed as the basis of the reduced expression of six7 in ljrp23ahub. Comparison of the phenotypes of the hypomorphic and knock-out alleles provides evidence of two independent roles in photoreceptor development. EdU and PH3 labeling show that the increase in rod number is associated with extended mitosis of photoreceptor progenitors, and TUNEL suggests that the lack of green-sensitive cones is the result of cell death of the cone precursor. These data add six7 to the small but growing list of essential genes for specification and patterning of photoreceptors in non-mammalian vertebrates, and highlight alterations in transcriptional regulation as a potential source of photoreceptor variation

  18. Switched Systems With Multiple Invariant Sets

    2015-05-06

    from [9]. Choose ẋp = Axp + bp, (15) but with A = [ −1 −10 10 −1 ] (16) b1 = [ 10 1 ] , b2 = [ −1 10 ] , b3 = [ 1 −10 ] . We are able to use the same...This amounted to a generalization and refinement of the argument presented in [9] and is in the spirit of dwell time methods for switched systems. This

  19. Modeling the Flexural Rigidity of Rod Photoreceptors

    Haeri, Mohammad; Knox, Barry E.; Ahmadi, Aphrodite

    2013-01-01

    In vertebrate eyes, the rod photoreceptor has a modified cilium with an extended cylindrical structure specialized for phototransduction called the outer segment (OS). The OS has numerous stacked membrane disks and can bend or break when subjected to mechanical forces. The OS exhibits axial structural variation, with extended bands composed of a few hundred membrane disks whose thickness is diurnally modulated. Using high-resolution confocal microscopy, we have observed OS flexing and disruption in live transgenic Xenopus rods. Based on the experimental observations, we introduce a coarse-grained model of OS mechanical rigidity using elasticity theory, representing the axial OS banding explicitly via a spring-bead model. We calculate a bending stiffness of ∼105 nN⋅μm2, which is seven orders-of-magnitude larger than that of typical cilia and flagella. This bending stiffness has a quadratic relation to OS radius, so that thinner OS have lower fragility. Furthermore, we find that increasing the spatial frequency of axial OS banding decreases OS rigidity, reducing its fragility. Moreover, the model predicts a tendency for OS to break in bands with higher spring number density, analogous to the experimental observation that transgenic rods tended to break preferentially in bands of high fluorescence. We discuss how pathological alterations of disk membrane properties by mutant proteins may lead to increased OS rigidity and thus increased breakage, ultimately contributing to retinal degeneration. PMID:23442852

  20. Exoplanet orbital eccentricity: multiplicity relation and the Solar System.

    Limbach, Mary Anne; Turner, Edwin L

    2015-01-06

    The known population of exoplanets exhibits a much wider range of orbital eccentricities than Solar System planets and has a much higher average eccentricity. These facts have been widely interpreted to indicate that the Solar System is an atypical member of the overall population of planetary systems. We report here on a strong anticorrelation of orbital eccentricity with multiplicity (number of planets in the system) among cataloged radial velocity (RV) systems. The mean, median, and rough distribution of eccentricities of Solar System planets fits an extrapolation of this anticorrelation to the eight-planet case rather precisely despite the fact that no more than two Solar System planets would be detectable with RV data comparable to that in the exoplanet sample. Moreover, even if regarded as a single or double planetary system, the Solar System lies in a reasonably heavily populated region of eccentricity-multiplicity space. Thus, the Solar System is not anomalous among known exoplanetary systems with respect to eccentricities when its multiplicity is taken into account. Specifically, as the multiplicity of a system increases, the eccentricity decreases roughly as a power law of index -1.20. A simple and plausible but ad hoc and model-dependent interpretation of this relationship implies that ∼ 80% of the one-planet and 25% of the two-planet systems in our sample have additional, as yet undiscovered, members but that systems of higher observed multiplicity are largely complete (i.e., relatively rarely contain additional undiscovered planets). If low eccentricities indeed favor high multiplicities, habitability may be more common in systems with a larger number of planets.

  1. Multiple wavelength multitimescale optical absorption system

    Lubis, R.; Allan, D.; Hodgson, B.W.; Swallow, A.J.

    1992-01-01

    A new workstation for pulse radiolysis studies has been developed for the Paterson Institute Linear Accelerator Laboratory. It is particularly suited to the study of materials available only in limited quantities. The analysing light beam is dispersed into a plane spectrum by a McPherson 270 monochromator and focused down to a line spectrum by a rod lens. The spectral intensity distribution is sampled by a linear array of optical fibres which conduct the light to photodiodes. A preamplifier unit amplifies and buffers the diode photocurrent signal which then passes to the main electronics unit incorporating further amplification stages, filters, backing-off of the background photocurrent, analog-to-digital conversion, data storage memory and a computer interface. All control of the electronic system is performed from a computer equipped with appropriate software. The system has 10 channels of spectral bandwidth 16 nm, a useful spectral response from 350 nm to 1 μm with a high signal-to-noise ratio, signal sampling rates from 20 MHz to 2 kHz and 8 kbyte of local memory for each channel. (author)

  2. Multiple wavelength multitimescale optical absorption system

    Lubis, R.; Allan, D.; Hodgson, B. W.; Swallow, A. J.

    A new workstation for pulse radiolysis studies has been developed for the Paterson Institute Linear Accelerator Laboratory. It is particularly suited to the study of materials available only in limited quantities. The analysing light beam is dispersed into a plane spectrum by a McPherson 270 monochromator and focused down to a line spectrum by a rod lens. The spectral intensity distribution is sampled by a linear array of optical fibres which conduct the light to photodiodes. A preamplifier unit amplifies and buffers the diode photocurrent signal which then passes to the main electronics unit incorporating further amplification stages, filters, backing-off of the background photocurrent, analog-to-digital conversion, data storage memory and a computer interface. All control of the electronic system is performed from a computer equipped with appropriate software. The system has 10 channels of spectral bandwidth 16 nm, a useful spectral response from 350 nm to 1 μm with a high signal-to-noise ratio, signal sampling rates from 20 MHz to 2 kHz and 8 kbyte of local memory for each channel.

  3. Maximising water supply system yield subject to multiple reliability ...

    Maximising water supply system yield subject to multiple reliability constraints via simulation-optimisation. ... Water supply systems have to satisfy different demands that each require various levels of reliability ... and monthly operating rules that maximise the yield of a water supply system subject to ... HOW TO USE AJOL.

  4. Modeling single versus multiple systems in implicit and explicit memory.

    Starns, Jeffrey J; Ratcliff, Roger; McKoon, Gail

    2012-04-01

    It is currently controversial whether priming on implicit tasks and discrimination on explicit recognition tests are supported by a single memory system or by multiple, independent systems. In a Psychological Review article, Berry and colleagues used mathematical modeling to address this question and provide compelling evidence against the independent-systems approach. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Seismic analysis of piping systems subjected to multiple support excitations

    Sundararajan, C.; Vaish, A.K.; Slagis, G.C.

    1981-01-01

    The paper presents the results of a comparative study between the multiple response spectrum method and the time-history method for the seismic analysis of nuclear piping systems subjected to different excitation at different supports or support groups. First, the necessary equations for the above analysis procedures are derived. Then, three actual nuclear piping systems subjected to single and multiple excitations are analyzed by the different methods, and extensive comparisons of the results (stresses) are made. Based on the results, it is concluded that the multiple response spectrum analysis gives acceptable results as compared to the ''exact'', but much more costly, time-history analysis. 6 refs

  6. Coexisting multiple attractors and riddled basins of a memristive system.

    Wang, Guangyi; Yuan, Fang; Chen, Guanrong; Zhang, Yu

    2018-01-01

    In this paper, a new memristor-based chaotic system is designed, analyzed, and implemented. Multistability, multiple attractors, and complex riddled basins are observed from the system, which are investigated along with other dynamical behaviors such as equilibrium points and their stabilities, symmetrical bifurcation diagrams, and sustained chaotic states. With different sets of system parameters, the system can also generate various multi-scroll attractors. Finally, the system is realized by experimental circuits.

  7. The role of carcinine in signaling at the Drosophila photoreceptor synapse.

    Brendan A Gavin

    2007-12-01

    Full Text Available The Drosophila melanogaster photoreceptor cell has long served as a model system for researchers focusing on how animal sensory neurons receive information from their surroundings and translate this information into chemical and electrical messages. Electroretinograph (ERG analysis of Drosophila mutants has helped to elucidate some of the genes involved in the visual transduction pathway downstream of the photoreceptor cell, and it is now clear that photoreceptor cell signaling is dependent upon the proper release and recycling of the neurotransmitter histamine. While the neurotransmitter transporters responsible for clearing histamine, and its metabolite carcinine, from the synaptic cleft have remained unknown, a strong candidate for a transporter of either substrate is the uncharacterized inebriated protein. The inebriated gene (ine encodes a putative neurotransmitter transporter that has been localized to photoreceptor cells in Drosophila and mutations in ine result in an abnormal ERG phenotype in Drosophila. Loss-of-function mutations in ebony, a gene required for the synthesis of carcinine in Drosophila, suppress components of the mutant ine ERG phenotype, while loss-of-function mutations in tan, a gene necessary for the hydrolysis of carcinine in Drosophila, have no effect on the ERG phenotype in ine mutants. We also show that by feeding wild-type flies carcinine, we can duplicate components of mutant ine ERGs. Finally, we demonstrate that treatment with H(3 receptor agonists or inverse agonists rescue several components of the mutant ine ERG phenotype. Here, we provide pharmacological and genetic epistatic evidence that ine encodes a carcinine neurotransmitter transporter. We also speculate that the oscillations observed in mutant ine ERG traces are the result of the aberrant activity of a putative H(3 receptor.

  8. The Role of Carcinine in Signaling at the Drosophila Photoreceptor Synapse

    Gavin, Brendan A; Arruda, Susan E; Dolph, Patrick J

    2007-01-01

    The Drosophila melanogaster photoreceptor cell has long served as a model system for researchers focusing on how animal sensory neurons receive information from their surroundings and translate this information into chemical and electrical messages. Electroretinograph (ERG) analysis of Drosophila mutants has helped to elucidate some of the genes involved in the visual transduction pathway downstream of the photoreceptor cell, and it is now clear that photoreceptor cell signaling is dependent upon the proper release and recycling of the neurotransmitter histamine. While the neurotransmitter transporters responsible for clearing histamine, and its metabolite carcinine, from the synaptic cleft have remained unknown, a strong candidate for a transporter of either substrate is the uncharacterized inebriated protein. The inebriated gene (ine) encodes a putative neurotransmitter transporter that has been localized to photoreceptor cells in Drosophila and mutations in ine result in an abnormal ERG phenotype in Drosophila. Loss-of-function mutations in ebony, a gene required for the synthesis of carcinine in Drosophila, suppress components of the mutant ine ERG phenotype, while loss-of-function mutations in tan, a gene necessary for the hydrolysis of carcinine in Drosophila, have no effect on the ERG phenotype in ine mutants. We also show that by feeding wild-type flies carcinine, we can duplicate components of mutant ine ERGs. Finally, we demonstrate that treatment with H3 receptor agonists or inverse agonists rescue several components of the mutant ine ERG phenotype. Here, we provide pharmacological and genetic epistatic evidence that ine encodes a carcinine neurotransmitter transporter. We also speculate that the oscillations observed in mutant ine ERG traces are the result of the aberrant activity of a putative H3 receptor. PMID:18069895

  9. Photoreceptor spectral sensitivity in the bumblebee, Bombus impatiens (Hymenoptera: Apidae.

    Peter Skorupski

    Full Text Available The bumblebee Bombus impatiens is increasingly used as a model in comparative studies of colour vision, or in behavioural studies relying on perceptual discrimination of colour. However, full spectral sensitivity data on the photoreceptor inputs underlying colour vision are not available for B. impatiens. Since most known bee species are trichromatic, with photoreceptor spectral sensitivity peaks in the UV, blue and green regions of the spectrum, data from a related species, where spectral sensitivity measurements have been made, are often applied to B impatiens. Nevertheless, species differences in spectral tuning of equivalent photoreceptor classes may result in peaks that differ by several nm, which may have small but significant effects on colour discrimination ability. We therefore used intracellular recording to measure photoreceptor spectral sensitivity in B. impatiens. Spectral peaks were estimated at 347, 424 and 539 nm for UV, blue and green receptors, respectively, suggesting that this species is a UV-blue-green trichromat. Photoreceptor spectral sensitivity peaks are similar to previous measurements from Bombus terrestris, although there is a significant difference in the peak sensitivity of the blue receptor, which is shifted in the short wave direction by 12-13 nm in B. impatiens compared to B. terrestris.

  10. Deep convolutional neural network based antenna selection in multiple-input multiple-output system

    Cai, Jiaxin; Li, Yan; Hu, Ying

    2018-03-01

    Antenna selection of wireless communication system has attracted increasing attention due to the challenge of keeping a balance between communication performance and computational complexity in large-scale Multiple-Input MultipleOutput antenna systems. Recently, deep learning based methods have achieved promising performance for large-scale data processing and analysis in many application fields. This paper is the first attempt to introduce the deep learning technique into the field of Multiple-Input Multiple-Output antenna selection in wireless communications. First, the label of attenuation coefficients channel matrix is generated by minimizing the key performance indicator of training antenna systems. Then, a deep convolutional neural network that explicitly exploits the massive latent cues of attenuation coefficients is learned on the training antenna systems. Finally, we use the adopted deep convolutional neural network to classify the channel matrix labels of test antennas and select the optimal antenna subset. Simulation experimental results demonstrate that our method can achieve better performance than the state-of-the-art baselines for data-driven based wireless antenna selection.

  11. Non-directional photoreceptors in the pluteus of Strongylocentrotus purpuratus

    Alberto Valero-Gracia

    2016-11-01

    Full Text Available In comparison to complex visual systems, non-directional photoreception – the most primitive form of biological photodetection – has been poorly investigated, although it is essential to many biological processes such as circadian and seasonal rhythms. Here we describe the spatiotemporal expression pattern of the major molecular actors mediating light reception – opsins – localized in the Strongylocentrotus purpuratus larva. In contrast to other zooplanktonic larvae, the echinopluteus lacks photoreceptor cells with observable shading pigments involved in directional visual tasks. Nonetheless, the echinopluteus expresses two distinct classes of opsins: a Go-opsin and a rhabdomeric opsin. The Go-opsin, Sp-opsin3.2, is detectable at early (3 days post fertilization and four armed pluteus stages (4 days post fertilization in two cells that flank the apical organ. To rule out the presence of shading pigments involved in directional photoreception, we used electron microscopy to explore the expression domain of Go-opsin Sp-opsin3.2 positive cells. The rhabdomeric opsin Sp-Opsin4 expression is detectable in clusters of cells located around the primary podia at the five-fold ectoderm pentagonal disc stage (day 18-21 and thereafter, thus indicating that Sp-Opsin4 may not be involved in the photoreception mechanism of the larva, but only of the juvenile. We discuss the putative function of the relevant cells in their neural context, and propose a model for understanding simple photodetection in marine larvae.

  12. Joint compensation of multiple RF impairments in MIMO STBC systems

    Qi, Jian

    2011-09-01

    In this paper, we propose a compensation method for the joint effect of high-power amplifier (HPA) nonlinearity, in-phase/quadrature-phase (I/Q) imbalance and crosstalk in multiple-input multiple-output (MIMO) orthogonal space-time block coding (OSTBC) systems. The performance of the MIMO OSTBC equipped with the proposed compensation mechanism is evaluated in terms of average symbol error probability and system capacity, in Rayleigh fading channels. Numerical results are provided and show the effects on performance of several system parameters, namely, the HPA parameters, image-leakage ratio, crosstalk, numbers of antennas, and phase-shift keying modulation order. © 2011 IEEE.

  13. Anaesthetic management of a patient with multiple system atrophy ...

    Multiple system atrophy (MSA) is a rare adult-onset neurodegenerative disease. Symptoms vary from autonomic dysfunction to Parkinsonism and cerebellar ataxia, in any combination. MSA affects many organ systems with many possible complications and makes perioperative management of a patient with this condition ...

  14. Criteria for stability of linear dynamical systems with multiple delays ...

    In this study we considered a linear Dynamical system with multiple delays and find suitable conditions on the systems parameters such that for a given initial function, we can define a mapping in a carefully chosen complete metric space on which the mapping has a unique fixed point. An asymptotic stability theory for the ...

  15. MULTIPLE PROJECTIONS SYSTEM (MPS) - USER'S MANUAL VERSION 1.0

    The report is a user's manual for version 1.0 of the Multiple Projections Systems (MPS), a computer system that can perform "what if" scenario analysis and report the final results (i.e., Rate of Further Progress - ROP - inventories) to EPA (i.e., the Aerometric Information Retri...

  16. On the performance of spectrum sharing systems with multiple antennas

    Yang, Liang

    2012-01-01

    In this paper, we study the capacity of spectrum sharing (SS) multiple-input multiple-output (MIMO) systems over Rayleigh fading channels. More specifically, we present closed-form capacity formulas for such systems with and without optimal power and rate adaptation. A lower bound on the capacity is also derived to characterize the scaling law of the capacity. Results show that increasing the number of antennas has a negative effect on the system capacity in the low signal-to-noise (SNR) regime and the scaling law at high SNR is similar to the conventional MIMO systems. In addition, a lower bound on the capacity of the SS keyhole MIMO channels is analyzed. We also present a capacity analysis of SS MIMO maximal ratio combining (MRC) systems and the results show that the capacity of such systems always decreases with the increase of the number of antennas. Numerical results are finally given to illustrate our analysis. © 2012 ICST.

  17. Multiple-state quantum Otto engine, 1D box system

    Latifah, E., E-mail: enylatifah@um.ac.id [Laboratory of Theoretical Physics and Natural Philosophy, Physics Department, Institut Teknologi Sepuluh Nopember, ITS, Surabaya, Indonesia and Physics Department, Malang State University (Indonesia); Purwanto, A. [Laboratory of Theoretical Physics and Natural Philosophy, Physics Department, Institut Teknologi Sepuluh Nopember, ITS, Surabaya (Indonesia)

    2014-03-24

    Quantum heat engines produce work using quantum matter as their working substance. We studied adiabatic and isochoric processes and defined the general force according to quantum system. The processes and general force are used to evaluate a quantum Otto engine based on multiple-state of one dimensional box system and calculate the efficiency. As a result, the efficiency depends on the ratio of initial and final width of system under adiabatic processes.

  18. Multiple-User, Multitasking, Virtual-Memory Computer System

    Generazio, Edward R.; Roth, Don J.; Stang, David B.

    1993-01-01

    Computer system designed and programmed to serve multiple users in research laboratory. Provides for computer control and monitoring of laboratory instruments, acquisition and anlaysis of data from those instruments, and interaction with users via remote terminals. System provides fast access to shared central processing units and associated large (from megabytes to gigabytes) memories. Underlying concept of system also applicable to monitoring and control of industrial processes.

  19. Intrinsic Variability in Multiple Systems and Clusters: Open Questions

    Lampens, P.

    2006-04-01

    It is most interesting and rewarding to probe the stellar structure of stars which belong to a system originating from the same parent cloud as this provides additional and more accurate constraints for the models. New results on pulsating components in multiple systems and clusters are beginning to emerge regularly. Based on concrete studies, I will present still unsolved problems and discuss some of the issues which may affect our understanding of the pulsation physics in such systems but also in general.

  20. Systemic Multiple Aneurysms Caused by Vascular Ehlers-Danlos Syndrome.

    Gui, Xinyu; Li, Fangda; Wu, Lingeer; Zheng, Yuehong

    2016-07-01

    Systemic multiple aneurysms are rare and usually associated with collagen tissue disease, such as Ehlers-Danlos syndrome (EDS) or Marfan syndrome. In the present case, we describe a 39-year-old male patient with systemic multiple aneurysms and acute intraperitoneal hemorrhage who was clinically diagnosed with vascular EDS. Coil embolization of the distal segment of the common hepatic artery was performed, which resolved the patient's symptoms. With this case presentation, we aim to increase the awareness of vascular EDS among clinicians and emphasize the extreme fragility of the arteries in patients with vascular EDS. © The Author(s) 2016.

  1. Steady State Analysis of Stochastic Systems with Multiple Time Delays

    Xu, W.; Sun, C. Y.; Zhang, H. Q.

    In this paper, attention is focused on the steady state analysis of a class of nonlinear dynamic systems with multi-delayed feedbacks driven by multiplicative correlated Gaussian white noises. The Fokker-Planck equations for delayed variables are at first derived by Novikov's theorem. Then, under small delay assumption, the approximate stationary solutions are obtained by the probability density approach. As a special case, the effects of multidelay feedbacks and the correlated additive and multiplicative Gaussian white noises on the response of a bistable system are considered. It is shown that the obtained analytical results are in good agreement with experimental results in Monte Carlo simulations.

  2. Predicting Harmonic Distortion of Multiple Converters in a Power System

    P. M. Ivry

    2017-01-01

    Full Text Available Various uncertainties arise in the operation and management of power systems containing Renewable Energy Sources (RES that affect the systems power quality. These uncertainties may arise due to system parameter changes or design parameter choice. In this work, the impact of uncertainties on the prediction of harmonics in a power system containing multiple Voltage Source Converters (VSCs is investigated. The study focuses on the prediction of harmonic distortion level in multiple VSCs when some system or design parameters are only known within certain constraints. The Univariate Dimension Reduction (UDR method was utilized in this study as an efficient predictive tool for the level of harmonic distortion of the VSCs measured at the Point of Common Coupling (PCC to the grid. Two case studies were considered and the UDR technique was also experimentally validated. The obtained results were compared with that of the Monte Carlo Simulation (MCS results.

  3. Multiplicity fluctuations and collective flow in small colliding systems

    Kawaguchi, Koji; Murase, Koichi; Hirano, Tetsufumi

    2017-11-01

    Recent observation of collective-flow-like behaviours in small colliding systems attracts significant theoretical and experimental interests. In large colliding systems, large collective flow has been interpreted as manifestation of almost-perfect fluidity of the quark gluon plasma (QGP). So it is quite intriguing to explore how small the QGP can be as a fluid. Multiplicity fluctuations play a crucial role in centrality definition of the events in small colliding systems since the fluctuations are, in general, more important as the system size is getting smaller. To consider the correct multiplicity fluctuations, we employ PYTHIA which naturally describes multiplicity distribution in p+p collisions. We superpose p+p collisions by taking into account the number of participants and that of binary collisions from Monte-Carlo version of Glauber model and evaluate initial entropy density distributions which contain not only multiplicity fluctuations but also fluctuations of longitudinal profiles. Solving hydrodynamic equations followed by the hadronic afterburner, we calculate transverse momentum spectra, elliptic and triangular flow parameters in p+Au, d+Au and 3He+Au collisions at the RHIC energy and p+Pb collisions at the LHC energy. Although a large fraction of final anisotropic flow parameters comes from the fluid-dynamical stage, the effects of hadronic rescatterings turn out to be also important as well in understanding of the flow data in small colliding systems.

  4. Multiple Energy System Analysis of Smart Energy Systems

    Thellufsen, Jakob Zinck

    2015-01-01

    thermal grids and smart gas grids, Smart Energy Systems moves the flexibility away from the fuel as is the case in current energy systems and into the system itself. However, most studies applying a Smart Energy System approach deals with analyses for either single countries or whole continents......To eliminate the use of fossil fuels in the energy sector it is necessary to transition to future 100% renewable energy systems. One approach for this radical change in our energy systems is Smart Energy Systems. With a focus on development and interaction between smart electricity grids, smart......, but it is unclear how regions, municipalities, and communities should deal with these national targets. It is necessary to be able to provide this information since Smart Energy Systems utilize energy resources and initiatives that have strong relations to local authorities and communities, such as onshore wind...

  5. Factors that influence the relative use of multiple memory systems.

    Packard, Mark G; Goodman, Jarid

    2013-11-01

    Neurobehavioral evidence supports the existence of at least two anatomically distinct "memory systems" in the mammalian brain that mediate dissociable types of learning and memory; a "cognitive" memory system dependent upon the hippocampus and a "stimulus-response/habit" memory system dependent upon the dorsolateral striatum. Several findings indicate that despite their anatomical and functional distinctiveness, hippocampal- and dorsolateral striatal-dependent memory systems may potentially interact and that, depending on the learning situation, this interaction may be cooperative or competitive. One approach to examining the neural mechanisms underlying these interactions is to consider how various factors influence the relative use of multiple memory systems. The present review examines several such factors, including information compatibility, temporal sequence of training, the visual sensory environment, reinforcement parameters, emotional arousal, and memory modulatory systems. Altering these parameters can lead to selective enhancements of either hippocampal-dependent or dorsolateral striatal-dependent memory, and bias animals toward the use of either cognitive or habit memory in dual-solution tasks that may be solved adequately with either memory system. In many learning situations, the influence of such experimental factors on the relative use of memory systems likely reflects a competitive interaction between the systems. Research examining how various factors influence the relative use of multiple memory systems may be a useful method for investigating how these systems interact with one another. Copyright © 2013 Wiley Periodicals, Inc.

  6. Multiple systems atrophy: Differentiation and findings by Magnetic resonance

    Vargas Velez, Sergio Alberto; Alzate Betancur, Catalina Maria

    2006-01-01

    Multiple system atrophy (MSA) is a neuro degenerative disorder of undetermined cause, characterized clinically by Parkinson's, autonomic, cerebellar or pyramidal sing and symptoms. lts differentiation from Parkinson's disease may be difficult, mainly in the early stages owing to overlapping features. Magnetic resonance imaging has demonstrated usefulness in MSA diagnosis and in differentiation with Parkinson's disease. One case with magnetic resonance findings is described

  7. An Elementary Semantics for Cardelli's System of Multiple Inheritance

    Fokkinga, M.M.

    1987-01-01

    In [Cardelli 84] Luca Cardelli gave a formal definition of a typed object-oriented language incorporating a sub-type relation used to describe multiple inheritance. Cardelli's fundamental result was a semantics for his system that enabled sub-typing to be modelled as straightforward set-inclusion.

  8. Multiple Measures Accountability Systems: A Perspective from Vermont

    Fowler, Amy

    2018-01-01

    In response to Bae's (2018) "Redesigning systems of school accountability: A multiple measures approach to accountability and support," this commentary expands on some key considerations for states and school districts as they seek different ways to support school improvement while also addressing the competing demands of educators,…

  9. Multiplicity in public health supply systems: a learning agenda.

    Bornbusch, Alan; Bates, James

    2013-08-01

    Supply chain integration-merging products for health programs into a single supply chain-tends to be the dominant model in health sector reform. However, multiplicity in a supply system may be justified as a risk management strategy that can better ensure product availability, advance specific health program objectives, and increase efficiency.

  10. A Multiple Sensor Machine Vision System Technology for the Hardwood

    Richard W. Conners; D.Earl Kline; Philip A. Araman

    1995-01-01

    For the last few years the authors have been extolling the virtues of a multiple sensor approach to hardwood defect detection. Since 1989 the authors have actively been trying to develop such a system. This paper details some of the successes and failures that have been experienced to date. It also discusses what remains to be done and gives time lines for the...

  11. Multiple-etalon systems for the Advanced Technology Solar Telescope

    Gary, G. Allen; Balasubramaniam, K. S.; Sigwarth, Michael

    2003-01-01

    Multiple etalon systems are discussed that meet the science requirements for a narrow-passband imaging system for the 4-meter National Solar Observatory (NSO)/Advance Technology Solar Telescope (ATST). A multiple etalon system can provide an imaging interferometer that works in four distinct modes: as a spectro-polarimeter, a filter-vector magnetograph, an intermediate-band imager, and broadband high-resolution imager. Specific dual and triple etalon configurations are described that provide a spectrographic passband of 2.0-3.5 micron and reduce parasitic light levels to 10(exp -4) as required for precise polarization measurement, e.g., Zeeman measurements of magnetic sensitive lines. A TESOS-like (Telecentric Etalon SOlar Spectrometer) triple etalon system provides a spectral purity of 10(exp -5). The triple designs have the advantage of reducing the finesse requirement on each etalon; allow the use of more stable blocking filters, and have very high spectral purity. A dual-etalon double-pass (Cavallini-like) system can provide a competing configuration. Such a dual-etalon design can provide high contrast. The selection of the final focal plane instrument will depend on a trade-off between an ideal instrument and practical reality. The trade study will include the number of etalons, their aperture sizes, complexities of the optical train, number of blocking filters, configuration of the electronic control system, computer interfaces, temperature controllers, etalon controllers, and their associated feedback electronics. The heritage of single and multiple etalon systems comes from their use in several observatories, including the Marshall Space Flight Center (MSFC) Solar Observatory, Sacramento Peak Observatory (NSO), and Kiepenheuer-Institut fur Sonnenphysik (KIS, Germany), Mees Solar Observatory (University of Hawaii), and Arcetri Astrophysical Observatory (Italy). The design of the ATST multiple etalon system will benefit from the experience gained at these

  12. Multiple excitation of supports - Part 2 : Implementation in TUBO system

    Galeao, A.C.N.R.; Barbosa, H.J.C.

    1980-12-01

    From the formulation of multiple excitation support problem, discussed in the first part of this work, and with the use of numerical techniques presented there, we discuss in this second part, the implementation in TUBO system, the follow procedure: Direct integration, Modal overlap, Spectral response emphasizing the aspects related to supports excitation. Finally, we present two numerical examples of TUBO system utilization in the solution of support movement problem. The several implemented computational procedures are compared. (E.G.) [pt

  13. Lateral interactions in the photoreceptor membrane: a NMR study

    Mollevanger, L.C.P.J.

    1987-01-01

    The photoreceptor membrane has an exceptionally high content of polyunsaturated fatty acyl chains combined with a high amount of phosphatidyl ethanolamine. It is situated in a cell organelle, the rod outer segment, with a high biological activity in which controlable trans-membrane currents of different ions play an important role. These characteristics make it a very interesting biological membrane to search for the existence of non-bilayer structures. Therefore in this thesis a detailed study of the polymorphic phase behaviour of the rod outer segment photoreceptor lipids was undertaken, concerning modulation of the polymorphic phase behaviour of photoreceptor membrane lipids by divalent cations and temperature, polymorphism of the individual phospholipid classes phosphatidylethanolamine and phosphatidylserine and effects of cholesterol, bilayer stabilization by (rhod)opsin. Morphologically intact rod outer segment possesses a large magnetic anisotropy. This property is used to obtain 31 P-NMR of oriented photoreceptor membranes which allows spectral analysis and identification of individual phospholipid classes, and allows to study lateral lipid diffusion in intact disk membranes. The power of high resolution solid state 13 C-NMR to study the conformation of the chromophore in rhodopsin is demonstrated. (Auth.)

  14. Cubozoan genome illuminates functional diversification of opsins and photoreceptor evolution

    Liegertová, Michaela; Pergner, Jiří; Kozmiková, Iryna; Fabian, Peter; Pombinho, António R.; Strnad, Hynek; Pačes, Jan; Vlček, Čestmír; Bartůněk, Petr; Kozmik, Zbyněk

    2015-01-01

    Roč. 5, Jul 8 (2015) ISSN 2045-2322 R&D Projects: GA ČR GAP305/10/2141; GA MŠk LO1220 Institutional support: RVO:68378050 Keywords : Cubozoan genome * opsins * photoreceptor * evolution Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.228, year: 2015

  15. Atypical retinal pigment epithelial defects with retained photoreceptor layers

    Giannakaki-Zimmermann, Helena; Querques, Giuseppe; Munch, Inger Christine

    2017-01-01

    BACKGROUND: To report patients with age-related macular degeneration and atypical central retinal pigment epithelium (RPE) defects not attributable to geographic atrophy (GA) or RPE-tears with overlying preserved photoreceptor layers. METHODS: Multimodal imaging case-series evaluating the course...

  16. Protein and signaling networks in vertebrate photoreceptor cells

    Karl-Wilhelm eKoch

    2015-11-01

    Full Text Available Vertebrate photoreceptor cells are exquisite light detectors operating under very dim and bright illumination. The photoexcitation and adaptation machinery in photoreceptor cells consists of protein complexes that can form highly ordered supramolecular structures and control the homeostasis and mutual dependence of the secondary messengers cGMP and Ca2+. The visual pigment in rod photoreceptors, the G protein-coupled receptor rhodopsin is organized in tracks of dimers thereby providing a signaling platform for the dynamic scaffolding of the G protein transducin. Illuminated rhodopsin is turned off by phosphorylation catalyzed by rhodopsin kinase GRK1 under control of Ca2+-recoverin. The GRK1 protein complex partly assembles in lipid raft structures, where shutting off rhodopsin seems to be more effective. Re-synthesis of cGMP is another crucial step in the recovery of the photoresponse after illumination. It is catalyzed by membrane bound sensory guanylate cyclases and is regulated by specific neuronal Ca2+-sensor proteins called GCAPs. At least one guanylate cyclase (ROS-GC1 was shown to be part of a multiprotein complex having strong interactions with the cytoskeleton and being controlled in a multimodal Ca2+-dependent fashion. The final target of the cGMP signaling cascade is a cyclic nucleotide-gated channel that is a hetero-oligomeric protein located in the plasma membrane and interacting with accessory proteins in highly organized microdomains. We summarize results and interpretations of findings related to the inhomogeneous organization of signaling units in photoreceptor outer segments.

  17. Kalman Filtering for Delayed Singular Systems with Multiplicative Noise

    Xiao Lu; Linglong Wang; Haixia Wang; Xianghua Wang

    2016-01-01

    Kalman filtering problem for singular systems is dealt with, where the measurements consist of instantaneous measurements and delayed ones, and the plant includes multiplicative noise. By utilizing standard singular value decomposition, the restricted equivalent delayed system is presented, and the Kalman filters for the restricted equivalent system are given by using the well-known re-organization of innovation analysis lemma. The optimal Kalman filter for the original system is given based on the above Kalman filter by recursive Riccati equations, and a numerical example is presented to show the validity and efficiency of the proposed approach, where the comparison between the filter and predictor is also given.

  18. Comparison of multiple support excitation solution techniques for piping systems

    Sterkel, H.P.; Leimbach, K.R.

    1980-01-01

    Design and analysis of nuclear power plant piping systems exposed to a variety of dynamic loads often require multiple support excitation analysis by modal or direct time integration methods. Both methods have recently been implemented in the computer program KWUROHR for static and dynamic analysis of piping systems, following the previous implementation of the multiple support excitation response spectrum method (see papers K 6/15 and K 6/15a of the SMiRT-4 Conference). The results of multiple support excitation response spectrum analyses can be examined by carrying out the equivalent time history analyses which do not distort the time phase relationship between the excitations at different support points. A frequent point of discussion is multiple versus single support excitation. A single support excitation analysis is computationally straightforward and tends to be on the conservative side, as the numerical results show. A multiple support excitation analysis, however, does not incur much more additional computer cost than the expenditure for an initial static solution involving three times the number, L, of excitation levels, i.e. 3L static load cases. The results are more realistic than those from a single support excitation analysis. A number of typical nuclear plant piping systems have been analyzed using single and multiple support excitation algorithms for: (1) the response spectrum method, (2) the modal time history method via the Wilson, Newmark and Goldberg integration operators and (3) the direct time history method via the Wilson integration operator. Characteristic results are presented to compare the computational quality of all three methods. (orig.)

  19. Multiple Etalon Systems for the Advanced Technology Solar Telescope

    Gary, G. Allen; Balasubramaniam, K. S.; Sigwarth, Michael; Six, N. Frank (Technical Monitor)

    2002-01-01

    Multiple etalons systems are discussed that meet the 4-meter NSO/Advance Technology Solar Telescope (http://www.nso.edu/ATST/index.html) instrument and science requirements for a narrow bandpass imaging system. A multiple etalon system can provide an imaging interferometer working in four distinct modes: as a spectro-polarimeter, a filter-vector magnetograph, and a wide-band and broad-band high-resolution imager. Specific dual and triple etalon configurations will be described that provides spectrographic passband of 2.0-3.5nm and reduces parasitic light levels to 1/10000 as required by precise polarization measurement, e.g., Zeeman measurements of magnetic sensitive lines. A TESOS-like triple etalon system provides for spectral purity of 100 thousandths. The triple designs have the advantage of reducing the finesse requirement on each etalon, allowing much more stable blocking filters, and can have very high spectral purity. A dual-etalon double-pass Cavallini-like configuration can provide a competing configuration. This design can provide high contrast with only a double etalon. The selection of the final focal plan instrument will depend on a trade-off of the ideal instrument versus reality, the number of etalons, the aperture of etalons, the number of blocking filters the electronic control system and computer interfaces, the temperature control and controllers for the etalons and the electronics. The use of existing experience should provide significant cost savings. The heritage of use of etalons and multiple etalon systems in solar physics come from a number of observatories, which includes MSFC Solar Observatory (NASA), Sac Peak Observatory (NSO), and Kiepenheuer Institute for Solar Physics (Germany), Mees Solar Observatory (University of Hawaii), and Arcetri Astrophysical Observatory (Italy). The design of the ATST multiple etalon system will reply on the existing experience from these observatories.

  20. Fundus Autofluorescence and Photoreceptor Cell Rosettes in Mouse Models

    Flynn, Erin; Ueda, Keiko; Auran, Emily; Sullivan, Jack M.; Sparrow, Janet R.

    2014-01-01

    Purpose. This study was conducted to study correlations among fundus autofluorescence (AF), RPE lipofuscin accumulation, and photoreceptor cell degeneration and to investigate the structural basis of fundus AF spots. Methods. Fundus AF images (55° lens; 488-nm excitation) and spectral-domain optical coherence tomography (SD-OCT) scans were acquired in pigmented Rdh8−/−/Abca4−/− mice (ages 1–9 months) with a confocal scanning laser ophthalmoscope (cSLO). For quantitative fundus AF (qAF), gray levels (GLs) were calibrated to an internal fluorescence reference. Retinal bisretinoids were measured by quantitative HPLC. Histometric analysis of outer nuclear layer (ONL) thicknesses was performed, and cryostat sections of retina were examined by fluorescence microscopy. Results. Quantified A2E and qAF intensities increased until age 4 months in the Rdh8−/−/Abca4−/− mice. The A2E levels declined after 4 months of age, but qAF intensity values continued to rise. The decline in A2E levels in the Rdh8−/−/Abca4−/− mice paralleled reduced photoreceptor cell viability as reflected in ONL thinning. Hyperautofluorescent puncta in fundus AF images corresponded to photoreceptor cell rosettes in SD-OCT images and histological sections stained with hematoxylin and eosin. The inner segment/outer segment–containing core of the rosette emitted an autofluorescence detected by fluorescence microscopy. Conclusions. When neural retina is disordered, AF from photoreceptor cells can contribute to noninvasive fundus AF images. Hyperautofluorescent puncta in fundus AF images are attributable, in at least some cases, to photoreceptor cell rosettes. PMID:25015357

  1. Retinal Thickening and Photoreceptor Loss in HIV Eyes without Retinitis.

    Cheryl A Arcinue

    Full Text Available To determine the presence of structural changes in HIV retinae (i.e., photoreceptor density and retinal thickness in the macula compared with age-matched HIV-negative controls.Cohort of patients with known HIV under CART (combination Antiretroviral Therapy treatment were examined with a flood-illuminated retinal AO camera to assess the cone photoreceptor mosaic and spectral-domain optical coherence tomography (SD-OCT to assess retinal layers and retinal thickness.Twenty-four eyes of 12 patients (n = 6 HIV-positive and 6 HIV-negative were imaged with the adaptive optics camera. In each of the regions of interest studied (nasal, temporal, superior, inferior, the HIV group had significantly less mean cone photoreceptor density compared with age-matched controls (difference range, 4,308-6,872 cones/mm2. A different subset of forty eyes of 20 patients (n = 10 HIV-positive and 10 HIV-negative was included in the retinal thickness measurements and retinal layer segmentation with the SD-OCT. We observed significant thickening in HIV positive eyes in the total retinal thickness at the foveal center, and in each of the three horizontal B-scans (through the macular center, superior, and inferior to the fovea. We also noted that the inner retina (combined thickness from ILM through RNFL to GCL layer was also significantly thickened in all the different locations scanned compared with HIV-negative controls.Our present study shows that the cone photoreceptor density is significantly reduced in HIV retinae compared with age-matched controls. HIV retinae also have increased macular retinal thickness that may be caused by inner retinal edema secondary to retinovascular disease in HIV. The interaction of photoreceptors with the aging RPE, as well as possible low-grade ocular inflammation causing diffuse inner retinal edema, may be the key to the progressive vision changes in HIV-positive patients without overt retinitis.

  2. Galerkin projection methods for solving multiple related linear systems

    Chan, T.F.; Ng, M.; Wan, W.L.

    1996-12-31

    We consider using Galerkin projection methods for solving multiple related linear systems A{sup (i)}x{sup (i)} = b{sup (i)} for 1 {le} i {le} s, where A{sup (i)} and b{sup (i)} are different in general. We start with the special case where A{sup (i)} = A and A is symmetric positive definite. The method generates a Krylov subspace from a set of direction vectors obtained by solving one of the systems, called the seed system, by the CG method and then projects the residuals of other systems orthogonally onto the generated Krylov subspace to get the approximate solutions. The whole process is repeated with another unsolved system as a seed until all the systems are solved. We observe in practice a super-convergence behaviour of the CG process of the seed system when compared with the usual CG process. We also observe that only a small number of restarts is required to solve all the systems if the right-hand sides are close to each other. These two features together make the method particularly effective. In this talk, we give theoretical proof to justify these observations. Furthermore, we combine the advantages of this method and the block CG method and propose a block extension of this single seed method. The above procedure can actually be modified for solving multiple linear systems A{sup (i)}x{sup (i)} = b{sup (i)}, where A{sup (i)} are now different. We can also extend the previous analytical results to this more general case. Applications of this method to multiple related linear systems arising from image restoration and recursive least squares computations are considered as examples.

  3. Distributed magnetic field positioning system using code division multiple access

    Prigge, Eric A. (Inventor)

    2003-01-01

    An apparatus and methods for a magnetic field positioning system use a fundamentally different, and advantageous, signal structure and multiple access method, known as Code Division Multiple Access (CDMA). This signal architecture, when combined with processing methods, leads to advantages over the existing technologies, especially when applied to a system with a large number of magnetic field generators (beacons). Beacons at known positions generate coded magnetic fields, and a magnetic sensor measures a sum field and decomposes it into component fields to determine the sensor position and orientation. The apparatus and methods can have a large `building-sized` coverage area. The system allows for numerous beacons to be distributed throughout an area at a number of different locations. A method to estimate position and attitude, with no prior knowledge, uses dipole fields produced by these beacons in different locations.

  4. Multiple-input multiple-output visible light communication system based on disorder dispersion components

    Yang, Tao; Zhang, Qi; Hao, Yue; Zhou, Xin-hui; Yi, Ming-dong; Wei, Wei; Huang, Wei; Li, Xing-ao

    2017-10-01

    A multiple-input multiple-output visible light communication (VLC) system based on disorder dispersion components is presented. Instead of monochromatic sources and large size photodetectors used in the traditional VLC systems, broadband sources with different spectra act as the transmitters and a compact imaging chip sensor accompanied by a disorder dispersion component and a calculating component serve as the receivers in the proposed system. This system has the merits of small size, more channels, simple structure, easy integration, and low cost. Simultaneously, the broadband sources are suitable to act as illumination sources for their white color. A regularized procedure is designed to solve a matrix equation for decoding the signals at the receivers. A proof-of-concept experiment using on-off keying modulation has been done to prove the feasibility of the design. The experimental results show that the signals decoded by the receivers fit well with those generated from the transmitters, but the bit error ratio is increased with the number of the signal channels. The experimental results can be further improved using a high-speed charge-coupled device, decreasing noises, and increasing the distance between the transmitters and the receivers.

  5. A faster technique for rendering meshes in multiple display systems

    Hand, Randall E.; Moorhead, Robert J., II

    2003-05-01

    Level of detail algorithms have widely been implemented in architectural VR walkthroughs and video games, but have not had widespread use in VR terrain visualization systems. This thesis explains a set of optimizations to allow most current level of detail algorithms run in the types of multiple display systems used in VR. It improves both the visual quality of the system through use of graphics hardware acceleration, and improves the framerate and running time through moifications to the computaitons that drive the algorithms. Using ROAM as a testbed, results show improvements between 10% and 100% on varying machines.

  6. Cell Fate of Müller Cells During Photoreceptor Regeneration in an N-Methyl-N-nitrosourea-Induced Retinal Degeneration Model of Zebrafish.

    Ogai, Kazuhiro; Hisano, Suguru; Sugitani, Kayo; Koriyama, Yoshiki; Kato, Satoru

    2016-01-01

    Zebrafish can regenerate several organs such as the tail fin, heart, central nervous system, and photoreceptors. Very recently, a study has demonstrated the photoreceptor regeneration in the alkylating agent N-methyl-N-nitrosourea (MNU)-induced retinal degeneration (RD) zebrafish model, in which whole photoreceptors are lost within a week after MNU treatment and then regenerated within a month. The research has also shown massive proliferation of Müller cells within a week. To address the question of whether proliferating Müller cells are the source of regenerating photoreceptors, which remains unknown in the MNU-induced zebrafish RD model, we employed a BrdU pulse-chase technique to label the proliferating cells within a week after MNU treatment. As a result of the BrdU pulse-chase technique, a number of BrdU(+) cells were observed in the outer nuclear layer as well as the inner nuclear layer. This implies that regenerating photoreceptors are derived from proliferating Müller cells in the zebrafish MNU-induced RD model.

  7. Association between systemic lupus erythematosus and multiple sclerosis: lupoid sclerosis

    Medina, Yimy F; Martinez, Jose B; Fernandez, Andres R; Quintana, Gerardo; Restrepo, Jose Felix; Rondon, Federico; Gamarra, Antonio Iglesias

    2010-01-01

    Multiple sclerosis (MS) and Systemic Lupus Erythematosus (SLE) with/without antiphospholipid syndrome are autoimmune illnesses. It has been described in many occasions the association of these two illnesses and the clinical picture of MS with characteristics of laboratory of SLE. When they affect to the central nervous system they can make it in a defined form for each illness or they can also make it in interposed or combined form of the two illnesses what has been called lupoid sclerosis; making that in some cases difficult the differentiation of the two illnesses and therefore to address the treatment. We present four cases of lupoid sclerosis, discuss the clinical and laboratory characteristics of this entity and we make a differentiation of the multiple sclerosis with the neurological affectation of SLE especially for images and laboratory results.

  8. Statin Induced Myopathy a Patient with Multiple Systemic Diseases

    Özgül Uçar

    2011-04-01

    Full Text Available Hydroxymethylglutaryl-coenzyme A reductase inhibitors (statins are the most successful class of drugs for the treatment of hypercholesterolaemia and dyslipidaemia. However, the popular profile of statins in terms of efficacy has been maligned by theiradverse effects. Statin induced myopathy, which can be seen at any time during the course of therapy, is a clinically important cause of statin intolerance and discontinuation. When a patient with multiple systemic diseases who use numerous medications represent with myalgia and muscle cramps, statin induced myopathy may not be remembered at first. We present a patient with multiple systemic diseases, alcohol and morphine abuse in whom myopathy developed. After exclusion of other etiologies, we concluded that myopathy was related to statin therapy.

  9. Memory-guided attention: Control from multiple memory systems

    Hutchinson, J. Benjamin; Turk-Browne, Nicholas B.

    2012-01-01

    Attention is strongly influenced by both external stimuli and internal goals. However, this useful dichotomy does not readily capture the ubiquitous and often automatic contribution of past experience stored in memory. We review recent evidence about how multiple memory systems control attention, consider how such interactions are manifested in the brain, and highlight how this framework for ‘memory-guided attention’ might help systematize previous findings and guide future research.

  10. Computation of subsonic flow around airfoil systems with multiple separation

    Jacob, K.

    1982-01-01

    A numerical method for computing the subsonic flow around multi-element airfoil systems was developed, allowing for flow separation at one or more elements. Besides multiple rear separation also sort bubbles on the upper surface and cove bubbles can approximately be taken into account. Also, compressibility effects for pure subsonic flow are approximately accounted for. After presentation the method is applied to several examples and improved in some details. Finally, the present limitations and desirable extensions are discussed.

  11. Multiple multichannel spectra acquisition and processing system with intelligent interface

    Chen Ying; Wei Yixiang; Qu Jianshi; Zheng Futang; Xu Shengkui; Xie Yuanming; Qu Xing; Ji Weitong; Qiu Xuehua

    1986-01-01

    A Multiple multichannel spectra acquisition and processing system with intelligent interface is described. Sixteen spectra measured with various lengths, channel widths, back biases and acquisition times can be identified and collected by the intelligent interface simultaneously while the connected computer is doing data processing. The execution time for the Ge(Li) gamma-ray spectrum analysis software on IBM PC-XT is about 55 seconds

  12. Existence of multiple solutions for quasilinear diagonal elliptic systems

    Marco Squassina

    1999-05-01

    Full Text Available Nonsmooth-critical-point theory is applied in proving multiplicity results for the quasilinear symmetric elliptic system $$ -sum_{i,j=1}^{n}D_j(a^{k}_{ij}(x,uD_iu_k+ {1over 2}sum_{i,j=1}^{n}sum_{h=1}^N D_{s_k}a^{h}_{ij}(x,uD_iu_hD_ju_h=g_k(x,u,, $$ for $k=1,..,N$.

  13. Generalised Multiplicative Indices of Polycyclic Aromatic Hydrocarbons and Benzenoid Systems

    Kulli, V. R.; Stone, Branden; Wang, Shaohui; Wei, Bing

    2017-05-01

    Many types of topological indices such as degree-based topological indices, distance-based topological indices, and counting-related topological indices are explored during past recent years. Among degree-based topological indices, Zagreb indices are the oldest one and studied well. In the paper, we define a generalised multiplicative version of these indices and compute exact formulas for Polycyclic Aromatic Hydrocarbons and jagged-rectangle Benzenoid systems.

  14. System and process for pulsed multiple reaction monitoring

    Belov, Mikhail E

    2013-05-17

    A new pulsed multiple reaction monitoring process and system are disclosed that uses a pulsed ion injection mode for use in conjunction with triple-quadrupole instruments. The pulsed injection mode approach reduces background ion noise at the detector, increases amplitude of the ion signal, and includes a unity duty cycle that provides a significant sensitivity increase for reliable quantitation of proteins/peptides present at attomole levels in highly complex biological mixtures.

  15. Analysis of a production/inventory system with multiple retailers

    Noblesse, Ann; Boute, Robert; Lambrecht, Marc; Van Houdt, B.

    2014-01-01

    We study a production/inventory system with one manufacturing plant and multiple retailers. Production lead times at the plant are stochastic and endogenously determined by the orders placed by the different retailers. Assuming stochastic (phase-type distributed) production and setup times, we make use of matrix analytic techniques to develop a queuing model that is capable to compute the distribution of the time orders spend in the production facility, depending on the retailer’s lot s...

  16. System and method for image registration of multiple video streams

    Dillavou, Marcus W.; Shum, Phillip Corey; Guthrie, Baron L.; Shenai, Mahesh B.; Deaton, Drew Steven; May, Matthew Benton

    2018-02-06

    Provided herein are methods and systems for image registration from multiple sources. A method for image registration includes rendering a common field of interest that reflects a presence of a plurality of elements, wherein at least one of the elements is a remote element located remotely from another of the elements and updating the common field of interest such that the presence of the at least one of the elements is registered relative to another of the elements.

  17. Stochastic dynamics of a delayed bistable system with multiplicative noise

    Dung, Nguyen Tien, E-mail: dung-nguyentien10@yahoo.com, E-mail: dungnt@fpt.edu.vn [Department of Mathematics, FPT University, No 8 Ton That Thuyet, My Dinh, Tu Liem, Hanoi (Viet Nam)

    2014-05-15

    In this paper we investigate the properties of a delayed bistable system under the effect of multiplicative noise. We first prove the existence and uniqueness of the positive solution and show that its moments are uniformly bounded. Then, we study stochastic dynamics of the solution in long time, the lower and upper bounds for the paths and an estimate for the average value are provided.

  18. SACHET, Dynamic Fission Products Inventory in PWR Multiple Compartment System

    Kodaira, Hideki

    1990-01-01

    1 - Description of program or function: SACHET evaluates the dynamic fission product inventories in the multiple compartment system of pressurized water reactor (PWR) plants. 2 - Method of solution: SACHET utilizes a matrix of fission product core inventory which is previously calculated by the ORIGEN code. 3 - Restrictions on the complexity of the problem: Liquid wastes such as chemical waste and detergent waste are not included

  19. Catalogue of Exoplanets in Multiple-Star-Systems

    Schwarz, Richard; Funk, Barbara; Bazsó, Ákos; Pilat-Lohinger, Elke

    2017-07-01

    Cataloguing the data of exoplanetary systems becomes more and more important, due to the fact that they conclude the observations and support the theoretical studies. Since 1995 there is a database which list most of the known exoplanets (The Extrasolar Planets Encyclopaedia is available at http://exoplanet.eu/ and described at Schneider et al. 2011). With the growing number of detected exoplanets in binary and multiple star systems it became more important to mark and to separate them into a new database. Therefore we started to compile a catalogue for binary and multiple star systems. Since 2013 the catalogue can be found at http://www.univie.ac.at/adg/schwarz/multiple.html (description can be found at Schwarz et al. 2016) which will be updated regularly and is linked to the Extrasolar Planets Encyclopaedia. The data of the binary catalogue can be downloaded as a file (.csv) and used for statistical purposes. Our database is divided into two parts: the data of the stars and the planets, given in a separate list. Every columns of the list can be sorted in two directions: ascending, meaning from the lowest value to the highest, or descending. In addition an introduction and help is also given in the menu bar of the catalogue including an example list.

  20. Collaboration Mechanism for Equipment Instruction of Multiple Energy Systems

    Wang, Dong; Wang, Tuo; Wang, Qi; Zhang, Zhao; Zhao, Mingyu; Wang, Yinghui

    2018-01-01

    When multiple energy systems execute optimization instructions simultaneously, and the same equipment is Shared, the instruction conflict may occur. Aiming at the above problems, taking into account the control objectives of each system, the characteristics of different systems, such as comprehensive clean energy, energy efficiency, and peak filling, etc., designed the instruction coordination mechanism for the daemon. This mechanism mainly acts on the main station of the system, and form a final optimization instruction. For some specific scenarios, the collaboration mechanism of unlocking the terminal is supplemented. The mechanism determines the specific execution instructions based on the arrival time of the instruction. Finally, the experiment in Tianjin eco-city shows that this algorithm can meet the instruction and collaboration requirements of multi-energy systems, and ensure the safe operation of the equipment.

  1. Monitoring system of multiple fire fighting based on computer vision

    Li, Jinlong; Wang, Li; Gao, Xiaorong; Wang, Zeyong; Zhao, Quanke

    2010-10-01

    With the high demand of fire control in spacious buildings, computer vision is playing a more and more important role. This paper presents a new monitoring system of multiple fire fighting based on computer vision and color detection. This system can adjust to the fire position and then extinguish the fire by itself. In this paper, the system structure, working principle, fire orientation, hydrant's angle adjusting and system calibration are described in detail; also the design of relevant hardware and software is introduced. At the same time, the principle and process of color detection and image processing are given as well. The system runs well in the test, and it has high reliability, low cost, and easy nodeexpanding, which has a bright prospect of application and popularization.

  2. Avian cone photoreceptors tile the retina as five independent, self-organizing mosaics.

    Yoseph A Kram

    2010-02-01

    Full Text Available The avian retina possesses one of the most sophisticated cone photoreceptor systems among vertebrates. Birds have five types of cones including four single cones, which support tetrachromatic color vision and a double cone, which is thought to mediate achromatic motion perception. Despite this richness, very little is known about the spatial organization of avian cones and its adaptive significance. Here we show that the five cone types of the chicken independently tile the retina as highly ordered mosaics with a characteristic spacing between cones of the same type. Measures of topological order indicate that double cones are more highly ordered than single cones, possibly reflecting their posited role in motion detection. Although cones show spacing interactions that are cell type-specific, all cone types use the same density-dependent yardstick to measure intercone distance. We propose a simple developmental model that can account for these observations. We also show that a single parameter, the global regularity index, defines the regularity of all five cone mosaics. Lastly, we demonstrate similar cone distributions in three additional avian species, suggesting that these patterning principles are universal among birds. Since regular photoreceptor spacing is critical for uniform sampling of visual space, the cone mosaics of the avian retina represent an elegant example of the emergence of adaptive global patterning secondary to simple local interactions between individual photoreceptors. Our results indicate that the evolutionary pressures that gave rise to the avian retina's various adaptations for enhanced color discrimination also acted to fine-tune its spatial sampling of color and luminance.

  3. Light- and GTP-activated hydrolysis of phosphatidylinositol bisphosphate in squid photoreceptor membranes

    Baer, K.M.; Saibil, H.R.

    1988-01-01

    Light stimulates the hydrolysis of exogenous, [ 3 H]inositol-labeled phosphatidylinositol bisphosphate (PtdInsP2) added to squid photoreceptor membranes, releasing inositol trisphosphate (InsP3). At free calcium levels of 0.05 microM or greater, hydrolysis of the labeled lipid is stimulated up to 4-fold by GTP and light together, but not separately. This activity is the biochemical counterpart of observations on intact retina showing that a rhodopsin-activated GTP-binding protein is involved in visual transduction in invertebrates, and that InsP3 release is correlated with visual excitation and adaptation. Using an in vitro assay, we investigated the calcium and GTP dependence of the phospholipase activity. At calcium concentrations between 0.1 and 0.5 microM, some hydrolysis occurs independently of GTP and light, with a light- and GTP-activated component superimposed. At 1 microM calcium there is no background activity, and hydrolysis absolutely requires both GTP and light. Ion exchange chromatography on Dowex 1 (formate form) of the water-soluble products released at 1 microM calcium reveals that the product is almost entirely InsP3. Invertebrate rhodopsin is homologous in sequence and function to vertebrate visual pigment, which modulates the concentration of cyclic GMP through the mediation of the GTP-binding protein transducin. While there is some evidence that light also modulates PtdInsP2 content in vertebrate photoreceptors, the case for its involvement in phototransduction is stronger for the invertebrate systems. The results reported here support the scheme of rhodopsin----GTP-binding protein----phospholipase C activation in invertebrate photoreceptors

  4. The giant mottled eel, Anguilla marmorata, uses blue-shifted rod photoreceptors during upstream migration.

    Wang, Feng-Yu; Fu, Wen-Chun; Wang, I-Li; Yan, Hong Young; Wang, Tzi-Yuan

    2014-01-01

    Catadromous fishes migrate between ocean and freshwater during particular phases of their life cycle. The dramatic environmental changes shape their physiological features, e.g. visual sensitivity, olfactory ability, and salinity tolerance. Anguilla marmorata, a catadromous eel, migrates upstream on dark nights, following the lunar cycle. Such behavior may be correlated with ontogenetic changes in sensory systems. Therefore, this study was designed to identify changes in spectral sensitivity and opsin gene expression of A. marmorata during upstream migration. Microspectrophotometry analysis revealed that the tropical eel possesses a duplex retina with rod and cone photoreceptors. The λmax of rod cells are 493, 489, and 489 nm in glass, yellow, and wild eels, while those of cone cells are 508, and 517 nm in yellow, and wild eels, respectively. Unlike European and American eels, Asian eels exhibited a blue-shifted pattern of rod photoreceptors during upstream migration. Quantitative gene expression analyses of four cloned opsin genes (Rh1f, Rh1d, Rh2, and SWS2) revealed that Rh1f expression is dominant at all three stages, while Rh1d is expressed only in older yellow eel. Furthermore, sequence comparison and protein modeling studies implied that a blue shift in Rh1d opsin may be induced by two known (N83, S292) and four putative (S124, V189, V286, I290) tuning sites adjacent to the retinal binding sites. Finally, expression of blue-shifted Rh1d opsin resulted in a spectral shift in rod photoreceptors. Our observations indicate that the giant mottled eel is color-blind, and its blue-shifted scotopic vision may influence its upstream migration behavior and habitat choice.

  5. The giant mottled eel, Anguilla marmorata, uses blue-shifted rod photoreceptors during upstream migration.

    Feng-Yu Wang

    Full Text Available Catadromous fishes migrate between ocean and freshwater during particular phases of their life cycle. The dramatic environmental changes shape their physiological features, e.g. visual sensitivity, olfactory ability, and salinity tolerance. Anguilla marmorata, a catadromous eel, migrates upstream on dark nights, following the lunar cycle. Such behavior may be correlated with ontogenetic changes in sensory systems. Therefore, this study was designed to identify changes in spectral sensitivity and opsin gene expression of A. marmorata during upstream migration. Microspectrophotometry analysis revealed that the tropical eel possesses a duplex retina with rod and cone photoreceptors. The λmax of rod cells are 493, 489, and 489 nm in glass, yellow, and wild eels, while those of cone cells are 508, and 517 nm in yellow, and wild eels, respectively. Unlike European and American eels, Asian eels exhibited a blue-shifted pattern of rod photoreceptors during upstream migration. Quantitative gene expression analyses of four cloned opsin genes (Rh1f, Rh1d, Rh2, and SWS2 revealed that Rh1f expression is dominant at all three stages, while Rh1d is expressed only in older yellow eel. Furthermore, sequence comparison and protein modeling studies implied that a blue shift in Rh1d opsin may be induced by two known (N83, S292 and four putative (S124, V189, V286, I290 tuning sites adjacent to the retinal binding sites. Finally, expression of blue-shifted Rh1d opsin resulted in a spectral shift in rod photoreceptors. Our observations indicate that the giant mottled eel is color-blind, and its blue-shifted scotopic vision may influence its upstream migration behavior and habitat choice.

  6. Performance analysis of commercial multiple-input-multiple-output access point in distributed antenna system.

    Fan, Yuting; Aighobahi, Anthony E; Gomes, Nathan J; Xu, Kun; Li, Jianqiang

    2015-03-23

    In this paper, we experimentally investigate the throughput of IEEE 802.11n 2x2 multiple-input-multiple-output (MIMO) signals in a radio-over-fiber-based distributed antenna system (DAS) with different fiber lengths and power imbalance. Both a MIMO-supported access point (AP) and a spatial-diversity-supported AP were separately employed in the experiments. Throughput measurements were carried out with wireless users at different locations in a typical office environment. For the different fiber length effect, the results indicate that MIMO signals can maintain high throughput when the fiber length difference between the two remote antenna units (RAUs) is under 100 m and falls quickly when the length difference is greater. For the spatial diversity signals, high throughput can be maintained even when the difference is 150 m. On the other hand, the separation of the MIMO antennas allows additional freedom in placing the antennas in strategic locations for overall improved system performance, although it may also lead to received power imbalance problems. The results show that the throughput performance drops in specific positions when the received power imbalance is above around 13 dB. Hence, there is a trade-off between the extent of the wireless coverage for moderate bit-rates and the area over which peak bit-rates can be achieved.

  7. Solutions on high-resolution multiple configuration system sensors

    Liu, Hua; Ding, Quanxin; Guo, Chunjie; Zhou, Liwei

    2014-11-01

    For aim to achieve an improved resolution in modern image domain, a method of continuous zoom multiple configuration, with a core optics is attempt to establish model by novel principle on energy transfer and high accuracy localization, by which the system resolution can be improved with a level in nano meters. A comparative study on traditional vs modern methods can demonstrate that the dialectical relationship and their balance is important, among Merit function, Optimization algorithms and Model parameterization. The effect of system evaluated criterion that MTF, REA, RMS etc. can support our arguments qualitatively.

  8. Geometric calibration method for multiple head cone beam SPECT systems

    Rizo, Ph.; Grangeat, P.; Guillemaud, R.; Sauze, R.

    1993-01-01

    A method is presented for performing geometric calibration on Single Photon Emission Tomography (SPECT) cone beam systems with multiple cone beam collimators, each having its own orientation parameters. This calibration method relies on the fact that, in tomography, for each head, the relative position of the rotation axis and of the collimator does not change during the acquisition. In order to ensure the method stability, the parameters to be estimated in intrinsic parameters and extrinsic parameters are separated. The intrinsic parameters describe the acquisition geometry and the extrinsic parameters position of the detection system with respect to the rotation axis. (authors) 3 refs

  9. Stress and multiple memory systems: from 'thinking' to 'doing'.

    Schwabe, Lars; Wolf, Oliver T

    2013-02-01

    Although it has been known for decades that stress influences memory performance, it was only recently shown that stress may alter the contribution of multiple, anatomically and functionally distinct memory systems to behavior. Here, we review recent animal and human studies demonstrating that stress promotes a shift from flexible 'cognitive' to rather rigid 'habit' memory systems and discuss, based on recent neuroimaging data in humans, the underlying brain mechanisms. We argue that, despite being generally adaptive, this stress-induced shift towards 'habit' memory may, in vulnerable individuals, be a risk factor for psychopathology. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. In vivo imaging of human photoreceptor mosaic with wavefront sensorless adaptive optics optical coherence tomography.

    Wong, Kevin S K; Jian, Yifan; Cua, Michelle; Bonora, Stefano; Zawadzki, Robert J; Sarunic, Marinko V

    2015-02-01

    Wavefront sensorless adaptive optics optical coherence tomography (WSAO-OCT) is a novel imaging technique for in vivo high-resolution depth-resolved imaging that mitigates some of the challenges encountered with the use of sensor-based adaptive optics designs. This technique replaces the Hartmann Shack wavefront sensor used to measure aberrations with a depth-resolved image-driven optimization algorithm, with the metric based on the OCT volumes acquired in real-time. The custom-built ultrahigh-speed GPU processing platform and fast modal optimization algorithm presented in this paper was essential in enabling real-time, in vivo imaging of human retinas with wavefront sensorless AO correction. WSAO-OCT is especially advantageous for developing a clinical high-resolution retinal imaging system as it enables the use of a compact, low-cost and robust lens-based adaptive optics design. In this report, we describe our WSAO-OCT system for imaging the human photoreceptor mosaic in vivo. We validated our system performance by imaging the retina at several eccentricities, and demonstrated the improvement in photoreceptor visibility with WSAO compensation.

  11. Simple ML Detector for Multiple Antennas Communication System

    Ahmad Taqwa

    2010-10-01

    Full Text Available In order to support providing broadband wireless communication services against limited and expensive frequency bandwidth, we have to develop a bandwidth efficient system. Therefore, in this paper we propose a closed-loop MIMO (Multiple-Input-Multiple-Output system using ML (Maximum Likelihood detector to optimize capacity and to increase system performance. What is especially exciting about the benefits offered by MIMO is that a high capacity and performance can be attained without additional frequency-spectral resource. The grand scenario of this concept is the attained advantages of transformation matrices having capability to allocate transmitted signals power suit to the channel. Furthermore, product of these matrices forms parallel singular channels. Due to zero inter-channels correlation, thus we can design ML detector to increase the system performance. Finally, computer simulations validates that at 0 dB SNR our system can reach optimal capacity up to 1 bps/Hz and SER up to 0.2 higher than opened-loop MIMO.

  12. Phase transitions in distributed control systems with multiplicative noise

    Allegra, Nicolas; Bamieh, Bassam; Mitra, Partha; Sire, Clément

    2018-01-01

    Contemporary technological challenges often involve many degrees of freedom in a distributed or networked setting. Three aspects are notable: the variables are usually associated with the nodes of a graph with limited communication resources, hindering centralized control; the communication is subject to noise; and the number of variables can be very large. These three aspects make tools and techniques from statistical physics particularly suitable for the performance analysis of such networked systems in the limit of many variables (analogous to the thermodynamic limit in statistical physics). Perhaps not surprisingly, phase-transition like phenomena appear in these systems, where a sharp change in performance can be observed with a smooth parameter variation, with the change becoming discontinuous or singular in the limit of infinite system size. In this paper, we analyze the so called network consensus problem, prototypical of the above considerations, that has previously been analyzed mostly in the context of additive noise. We show that qualitatively new phase-transition like phenomena appear for this problem in the presence of multiplicative noise. Depending on dimensions, and on the presence or absence of a conservation law, the system performance shows a discontinuous change at a threshold value of the multiplicative noise strength. In the absence of the conservation law, and for graph spectral dimension less than two, the multiplicative noise threshold (the stability margin of the control problem) is zero. This is reminiscent of the absence of robust controllers for certain classes of centralized control problems. Although our study involves a ‘toy’ model, we believe that the qualitative features are generic, with implications for the robust stability of distributed control systems, as well as the effect of roundoff errors and communication noise on distributed algorithms.

  13. Kalman Filtering for Delayed Singular Systems with Multiplicative Noise

    Xiao Lu; Linglong Wang; Haixia Wang; Xianghua Wang

    2016-01-01

    Kalman filtering problem for singular systems is dealt with,where the measurements consist of instantaneous measurements and delayed ones,and the plant includes multiplicative noise.By utilizing standard singular value decomposition,the restricted equivalent delayed system is presented,and the Kalman filters for the restricted equivalent system are given by using the well-known re-organization of innovation analysis lemma.The optimal Kalman filter for the original system is given based on the above Kalman filter by recursive Riccati equations,and a numerical example is presented to show the validity and efficiency of the proposed approach,where the comparison between the filter and predictor is also given.

  14. Orbital parameters of the multiple system EM Boo

    Özkardeş, B.; Bakış, H.; Bakış, V.

    2018-02-01

    EM Boo is a relatively bright (V = 8.98 mag.) and short orbital period (P⁓2.45 days) binary star member of the multiple system WDS J14485+2445AB. There is neither photometric nor spectroscopic study of the system in the literature. In this work, we obtained spectroscopic orbital parameters of the system from new high resolution spectroscopic observations made with échelle spectrograph attached to UBT60 telescope of Akdeniz University. The spectroscopic solution yielded the values K1 = 100.7±2.6 km/s, K2 = 120.1±2.6 km/s and Vγ = -14.6±3.1 km/s, and thus the mass ratio of the system q = 0.838±0.064.

  15. Effective field theories for superconducting systems with multiple Fermi surfaces

    Braga, P.R., E-mail: pedro.rangel.braga@gmail.com [Departamento de Física Teórica, Instituto de Física, UERJ - Universidade do Estado do Rio de Janeiro, Rua São Francisco Xavier 524, 20550-013 Maracanã, Rio de Janeiro (Brazil); Granado, D.R., E-mail: diegorochagrana@uerj.br [Departamento de Física Teórica, Instituto de Física, UERJ - Universidade do Estado do Rio de Janeiro, Rua São Francisco Xavier 524, 20550-013 Maracanã, Rio de Janeiro (Brazil); Department of Physics and Astronomy, Ghent University, Krijgslaan 281-S9, 9000 Gent (Belgium); Guimaraes, M.S., E-mail: msguimaraes@uerj.br [Departamento de Física Teórica, Instituto de Física, UERJ - Universidade do Estado do Rio de Janeiro, Rua São Francisco Xavier 524, 20550-013 Maracanã, Rio de Janeiro (Brazil); Wotzasek, C., E-mail: clovis@if.ufrj.br [Instituto de Física, Universidade Federal do Rio de Janeiro, 21941-972, Rio de Janeiro (Brazil)

    2016-11-15

    In this work we investigate the description of superconducting systems with multiple Fermi surfaces. For the case of one Fermi surface we re-obtain the result that the superconductor is more precisely described as a topological state of matter. Studying the case of more than one Fermi surface, we obtain the effective theory describing a time reversal symmetric topological superconductor. These results are obtained by employing a general procedure to construct effective low energy actions describing states of electromagnetic systems interacting with charges and defects. The procedure consists in taking into account the proliferation or dilution of these charges and defects and its consequences for the low energy description of the electromagnetic response of the system. We find that the main ingredient entering the low energy characterization of the system with more than one Fermi surface is a non-conservation of the canonical supercurrent triggered by particular vortex configurations.

  16. The Retinal Pigment Epithelium: a Convenient Source of New Photoreceptor cells?

    Shu-Zhen Wang

    2014-01-01

    Full Text Available Recent success in restoring visual function through photoreceptor replacement in mouse models of photoreceptor degeneration intensifies the need to generate or regenerate photoreceptor cells for the ultimate goal of using cell replacement therapy for blindness caused by photoreceptor degeneration. Current research on deriving new photoreceptors for replacement, as regenerative medicine in general, focuses on the use of embryonic stem cells and induced pluripotent stem (iPS cells to generate transplantable cells. Nonetheless, naturally occurring regeneration, such as wound healing, involves awakening cells at or near a wound site to produce new cells needed to heal the wound. Here we discuss the possibility of tweaking an ocular tissue, the retinal pigment epithelium (RPE, to produce photoreceptor cells in situ in the eye. Unlike the neural retina, the RPE in adult mammals maintains cell proliferation capability. Furthermore, progeny cells from RPE proliferation may differentiate into cells other than RPE. The combination of proliferation and plasticity opens a question of whether they could be channeled by a regulatory gene with pro-photoreceptor activity towards photoreceptor production. Studies using embryonic chick and transgenic mouse showed that indeed photoreceptor-like cells were produced in culture and in vivo in the eye using genedirected reprogramming of RPE cells, supporting the feasibility of using the RPE as a convenient source of new photoreceptor cells for in situ retinal repair without involving cell transplantation.

  17. A Timing-Driven Partitioning System for Multiple FPGAs

    Kalapi Roy

    1996-01-01

    Full Text Available Field-programmable systems with multiple FPGAs on a PCB or an MCM are being used by system designers when a single FPGA is not sufficient. We address the problem of partitioning a large technology mapped FPGA circuit onto multiple FPGA devices of a specific target technology. The physical characteristics of the multiple FPGA system (MFS pose additional constraints to the circuit partitioning algorithms: the capacity of each FPGA, the timing constraints, the number of I/Os per FPGA, and the pre-designed interconnection patterns of each FPGA and the package. Existing partitioning techniques which minimize just the cut sizes of partitions fail to satisfy the above challenges. We therefore present a timing driven N-way partitioning algorithm based on simulated annealing for technology-mapped FPGA circuits. The signal path delays are estimated during partitioning using a timing model specific to a multiple FPGA architecture. The model combines all possible delay factors in a system with multiple FPGA chips of a target technology. Furthermore, we have incorporated a new dynamic net-weighting scheme to minimize the number of pin-outs for each chip. Finally, we have developed a graph-based global router for pin assignment which can handle the pre-routed connections of our MFS structure. In order to reduce the time spent in the simulated annealing phase of the partitioner, clusters of circuit components are identified by a new linear-time bottom-up clustering algorithm. The annealing-based N-way partitioner executes four times faster using the clusters as opposed to a flat netlist with improved partitioning results. For several industrial circuits, our approach outperforms the recursive min-cut bi-partitioning algorithm by 35% in terms of nets cut. Our approach also outperforms an industrial FPGA partitioner by 73% on average in terms of unroutable nets. Using the performance optimization capabilities in our approach we have successfully partitioned the

  18. Simultaneous real-time monitoring of multiple cortical systems.

    Gupta, Disha; Jeremy Hill, N; Brunner, Peter; Gunduz, Aysegul; Ritaccio, Anthony L; Schalk, Gerwin

    2014-10-01

    Real-time monitoring of the brain is potentially valuable for performance monitoring, communication, training or rehabilitation. In natural situations, the brain performs a complex mix of various sensory, motor or cognitive functions. Thus, real-time brain monitoring would be most valuable if (a) it could decode information from multiple brain systems simultaneously, and (b) this decoding of each brain system were robust to variations in the activity of other (unrelated) brain systems. Previous studies showed that it is possible to decode some information from different brain systems in retrospect and/or in isolation. In our study, we set out to determine whether it is possible to simultaneously decode important information about a user from different brain systems in real time, and to evaluate the impact of concurrent activity in different brain systems on decoding performance. We study these questions using electrocorticographic signals recorded in humans. We first document procedures for generating stable decoding models given little training data, and then report their use for offline and for real-time decoding from 12 subjects (six for offline parameter optimization, six for online experimentation). The subjects engage in tasks that involve movement intention, movement execution and auditory functions, separately, and then simultaneously. Main Results: Our real-time results demonstrate that our system can identify intention and movement periods in single trials with an accuracy of 80.4% and 86.8%, respectively (where 50% would be expected by chance). Simultaneously, the decoding of the power envelope of an auditory stimulus resulted in an average correlation coefficient of 0.37 between the actual and decoded power envelopes. These decoders were trained separately and executed simultaneously in real time. This study yielded the first demonstration that it is possible to decode simultaneously the functional activity of multiple independent brain systems. Our

  19. Reliability Analysis Multiple Redundancy Controller for Nuclear Safety Systems

    Son, Gwangseop; Kim, Donghoon; Son, Choulwoong

    2013-01-01

    This controller is configured for multiple modular redundancy (MMR) composed of dual modular redundancy (DMR) and triple modular redundancy (TMR). The architecture of MRC is briefly described, and the Markov model is developed. Based on the model, the reliability and Mean Time To Failure (MTTF) are analyzed. In this paper, the architecture of MRC for nuclear safety systems is described. The MRC is configured for multiple modular redundancy (MMR) composed of dual modular redundancy (DMR) and triple modular redundancy (TMR). Markov models for MRC architecture was developed, and then the reliability was analyzed by using the model. From the reliability analyses for the MRC, it is obtained that the failure rate of each module in the MRC should be less than 2 Χ 10 -4 /hour and the MTTF average increase rate depending on FCF increment, i. e. ΔMTTF/ΔFCF, is 4 months/0.1

  20. Multiple fuel supply system for an internal combustion engine

    Crothers, William T.

    1977-01-01

    A multiple fuel supply or an internal combustion engine wherein phase separation of components is deliberately induced. The resulting separation permits the use of a single fuel tank to supply components of either or both phases to the engine. Specifically, phase separation of a gasoline/methanol blend is induced by the addition of a minor amount of water sufficient to guarantee separation into an upper gasoline phase and a lower methanol/water phase. A single fuel tank holds the two-phase liquid with separate fuel pickups and separate level indicators for each phase. Either gasoline or methanol, or both, can be supplied to the engine as required by predetermined parameters. A fuel supply system for a phase-separated multiple fuel supply contained in a single fuel tank is described.

  1. The Ste20 kinase misshapen regulates both photoreceptor axon targeting and dorsal closure, acting downstream of distinct signals.

    Su, Y C; Maurel-Zaffran, C; Treisman, J E; Skolnik, E Y

    2000-07-01

    We have previously shown that the Ste20 kinase encoded by misshapen (msn) functions upstream of the c-Jun N-terminal kinase (JNK) mitogen-activated protein kinase module in Drosophila. msn is required to activate the Drosophila JNK, Basket (Bsk), to promote dorsal closure of the embryo. A mammalian homolog of Msn, Nck interacting kinase, interacts with the SH3 domains of the SH2-SH3 adapter protein Nck. We now show that Msn likewise interacts with Dreadlocks (Dock), the Drosophila homolog of Nck. dock is required for the correct targeting of photoreceptor axons. We have performed a structure-function analysis of Msn in vivo in Drosophila in order to elucidate the mechanism whereby Msn regulates JNK and to determine whether msn, like dock, is required for the correct targeting of photoreceptor axons. We show that Msn requires both a functional kinase and a C-terminal regulatory domain to activate JNK in vivo in Drosophila. A mutation in a PXXP motif on Msn that prevents it from binding to the SH3 domains of Dock does not affect its ability to rescue the dorsal closure defect in msn embryos, suggesting that Dock is not an upstream regulator of msn in dorsal closure. Larvae with only this mutated form of Msn show a marked disruption in photoreceptor axon targeting, implicating an SH3 domain protein in this process; however, an activated form of Msn is not sufficient to rescue the dock mutant phenotype. Mosaic analysis reveals that msn expression is required in photoreceptors in order for their axons to project correctly. The data presented here genetically link msn to two distinct biological events, dorsal closure and photoreceptor axon pathfinding, and thus provide the first evidence that Ste20 kinases of the germinal center kinase family play a role in axonal pathfinding. The ability of Msn to interact with distinct classes of adapter molecules in dorsal closure and photoreceptor axon pathfinding may provide the flexibility that allows it to link to distinct

  2. Multiple-beam LDV system for buried landmine detection

    Lal, Amit K.; Zhang, Hansheng; Aranchuk, Vyacheslav; Hurtado, Ernesto; Hess, Cecil F.; Burgett, Richard D.; Sabatier, James M.

    2003-09-01

    This paper discusses the performance and experimental results of a multiple beam laser Doppler vibrometer designed to locate buried landmines with the laser-acoustic technique. The device increases the speed of landmine detection by simultaneously probing 16 positions on the ground over a span of 1 meter, and measuring the ground velocity at each of these positions. Experimental results are presented from controlled laboratory experiments as well as from landmine test lanes at the University of Mississippi. In the mine lanes, the multiple beam system is raised to a height of 2.5 meters with a forklift, with the 16 beams spread over a 1 meter line along the mine lane. A motor system then allows the 16 beams to be translated across the mine lane, enabling the system to scan a 1 x 1 meter area in a much shorter time than with previous scanning techniques. The effects of experimental parameters such as platform motion, angle of incidence, speckle dropout, and system depth-of-field will be presented and discussed.

  3. Integrity of the cone photoreceptor mosaic in oligocone trichromacy

    Michaelides, Michel; Rha, Jungtae; Dees, Elise W

    2011-01-01

    Oligocone trichromacy (OT) is an unusual cone dysfunction syndrome characterized by reduced visual acuity, mild photophobia, reduced amplitude of the cone electroretinogram with normal rod responses, normal fundus appearance, and normal or near-normal color vision. It has been proposed that these...... that these patients have a reduced number of normal functioning cones (oligocone). This paper has sought to evaluate the integrity of the cone photoreceptor mosaic in four patients previously described as having OT....

  4. Responses of crayfish photoreceptor cells following intense light adaptation.

    Cummins, D R; Goldsmith, T H

    1986-01-01

    After intense orange adapting exposures that convert 80% of the rhodopsin in the eye to metarhodopsin, rhabdoms become covered with accessory pigment and appear to lose some microvillar order. Only after a delay of hours or even days is the metarhodopsin replaced by rhodopsin (Cronin and Goldsmith 1984). After 24 h of dark adaptation, when there has been little recovery of visual pigment, the photoreceptor cells have normal resting potentials and input resistances, and the reversal potential of the light response is 10-15 mV (inside positive), unchanged from controls. The log V vs log I curve is shifted about 0.6 log units to the right on the energy axis, quantitatively consistent with the decrease in the probability of quantum catch expected from the lowered concentration of rhodopsin in the rhabdoms. Furthermore, at 24 h the photoreceptors exhibit a broader spectral sensitivity than controls, which is also expected from accumulations of metarhodopsin in the rhabdoms. In three other respects, however, the transduction process appears to be light adapted: The voltage responses are more phasic than those of control photoreceptors. The relatively larger effect (compared to controls) of low extracellular Ca++ (1 mmol/l EGTA) in potentiating the photoresponses suggests that the photoreceptors may have elevated levels of free cytoplasmic Ca++. The saturating depolarization is only about 30% as large as the maximal receptor potentials of contralateral, dark controls, and by that measure the log V-log I curve is shifted downward by 0.54 log units.(ABSTRACT TRUNCATED AT 250 WORDS)

  5. Early photoreceptor outer segment loss and retinoschisis in Cohen syndrome.

    Uyhazi, Katherine E; Binenbaum, Gil; Carducci, Nicholas; Zackai, Elaine H; Aleman, Tomas S

    2018-06-01

    To describe early structural and functional retinal changes in a patient with Cohen syndrome. A 13-month-old Caucasian girl of Irish and Spanish ancestry was noted to have micrognathia and laryngomalacia at birth, which prompted a genetic evaluation that revealed biallelic deletions in COH1 (VPS13B) (a maternally inherited 60-kb deletion involving exons 26-32 and a paternally inherited 3.5-kb deletion within exon 17) consistent with Cohen syndrome. She underwent a complete ophthalmic examination, full-field flash electroretinography and retinal imaging with spectral domain optical coherence tomography. Central vision was central, steady, and maintained. There was bilateral myopic astigmatic refractive error. Fundus exam was notable for dark foveolar pigmentation, but no obvious abnormalities of either eye. Spectral domain optical coherence tomography cross sections through the fovea revealed a normal appearing photoreceptor outer nuclear layer but loss of the interdigitation signal between the photoreceptor outer segments and the apical retinal pigment epithelium. Retinoschisis involving the inner nuclear layer of both eyes and possible ganglion cell layer thinning were also noted. There was a detectable electroretinogram with similarly reduced amplitudes of rod- (white, 0.01 cd.s.m -2 ) and cone-mediated (3 cd.s.m -2 , 30 Hz) responses. Photoreceptor outer segment abnormalities and retinoschisis may represent the earliest structural retinal change detected by spectral domain optical coherence tomography in patients with Cohen syndrome, suggesting a complex pathophysiology with primary involvement of the photoreceptor cilium and disorganization of the structural integrity of the inner retina.

  6. Does Apoptosis Regulate the Function of Retinal Photoreceptors?

    Halaby, Reginald

    2012-01-01

    Apoptosis, or programmed cell death, is an integral component of developmental biology, embryology, and anatomy. All eukaryotic cells possess the molecular machinery necessary to execute apoptosis. However, dysregulated apoptosis in the form of too much or too little cell death results in diseases such as Alzheimer’s disease, autoimmune disorders, and cancer. It is postulated that apoptosis of the photoreceptors in the retina plays a vital role in mediating vision, and evidence is presented h...

  7. MACSIMS : multiple alignment of complete sequences information management system

    Plewniak Frédéric

    2006-06-01

    Full Text Available Abstract Background In the post-genomic era, systems-level studies are being performed that seek to explain complex biological systems by integrating diverse resources from fields such as genomics, proteomics or transcriptomics. New information management systems are now needed for the collection, validation and analysis of the vast amount of heterogeneous data available. Multiple alignments of complete sequences provide an ideal environment for the integration of this information in the context of the protein family. Results MACSIMS is a multiple alignment-based information management program that combines the advantages of both knowledge-based and ab initio sequence analysis methods. Structural and functional information is retrieved automatically from the public databases. In the multiple alignment, homologous regions are identified and the retrieved data is evaluated and propagated from known to unknown sequences with these reliable regions. In a large-scale evaluation, the specificity of the propagated sequence features is estimated to be >99%, i.e. very few false positive predictions are made. MACSIMS is then used to characterise mutations in a test set of 100 proteins that are known to be involved in human genetic diseases. The number of sequence features associated with these proteins was increased by 60%, compared to the features available in the public databases. An XML format output file allows automatic parsing of the MACSIM results, while a graphical display using the JalView program allows manual analysis. Conclusion MACSIMS is a new information management system that incorporates detailed analyses of protein families at the structural, functional and evolutionary levels. MACSIMS thus provides a unique environment that facilitates knowledge extraction and the presentation of the most pertinent information to the biologist. A web server and the source code are available at http://bips.u-strasbg.fr/MACSIMS/.

  8. Luminescence- and nanoparticle-mediated increase of light absorption by photoreceptor cells: Converting UV light to visible light.

    Li, Lei; Sahi, Sunil K; Peng, Mingying; Lee, Eric B; Ma, Lun; Wojtowicz, Jennifer L; Malin, John H; Chen, Wei

    2016-02-10

    We developed new optic devices - singly-doped luminescence glasses and nanoparticle-coated lenses that convert UV light to visible light - for improvement of visual system functions. Tb(3+) or Eu(3+) singly-doped borate glasses or CdS-quantum dot (CdS-QD) coated lenses efficiently convert UV light to 542 nm or 613 nm wavelength narrow-band green or red light, or wide-spectrum white light, and thereby provide extra visible light to the eye. In zebrafish (wild-type larvae and adult control animals, retinal degeneration mutants, and light-induced photoreceptor cell degeneration models), the use of Tb(3+) or Eu(3+) doped luminescence glass or CdS-QD coated glass lenses provide additional visible light to the rod and cone photoreceptor cells, and thereby improve the visual system functions. The data provide proof-of-concept for the future development of optic devices for improvement of visual system functions in patients who suffer from photoreceptor cell degeneration or related retinal diseases.

  9. Prediction of Multiple-Trait and Multiple-Environment Genomic Data Using Recommender Systems

    Montesinos-López, Osval A.; Montesinos-López, Abelardo; Crossa, José; Montesinos-López, José C.; Mota-Sanchez, David; Estrada-González, Fermín; Gillberg, Jussi; Singh, Ravi; Mondal, Suchismita; Juliana, Philomin

    2018-01-01

    In genomic-enabled prediction, the task of improving the accuracy of the prediction of lines in environments is difficult because the available information is generally sparse and usually has low correlations between traits. In current genomic selection, although researchers have a large amount of information and appropriate statistical models to process it, there is still limited computing efficiency to do so. Although some statistical models are usually mathematically elegant, many of them are also computationally inefficient, and they are impractical for many traits, lines, environments, and years because they need to sample from huge normal multivariate distributions. For these reasons, this study explores two recommender systems: item-based collaborative filtering (IBCF) and the matrix factorization algorithm (MF) in the context of multiple traits and multiple environments. The IBCF and MF methods were compared with two conventional methods on simulated and real data. Results of the simulated and real data sets show that the IBCF technique was slightly better in terms of prediction accuracy than the two conventional methods and the MF method when the correlation was moderately high. The IBCF technique is very attractive because it produces good predictions when there is high correlation between items (environment–trait combinations) and its implementation is computationally feasible, which can be useful for plant breeders who deal with very large data sets. PMID:29097376

  10. Prediction of Multiple-Trait and Multiple-Environment Genomic Data Using Recommender Systems.

    Montesinos-López, Osval A; Montesinos-López, Abelardo; Crossa, José; Montesinos-López, José C; Mota-Sanchez, David; Estrada-González, Fermín; Gillberg, Jussi; Singh, Ravi; Mondal, Suchismita; Juliana, Philomin

    2018-01-04

    In genomic-enabled prediction, the task of improving the accuracy of the prediction of lines in environments is difficult because the available information is generally sparse and usually has low correlations between traits. In current genomic selection, although researchers have a large amount of information and appropriate statistical models to process it, there is still limited computing efficiency to do so. Although some statistical models are usually mathematically elegant, many of them are also computationally inefficient, and they are impractical for many traits, lines, environments, and years because they need to sample from huge normal multivariate distributions. For these reasons, this study explores two recommender systems: item-based collaborative filtering (IBCF) and the matrix factorization algorithm (MF) in the context of multiple traits and multiple environments. The IBCF and MF methods were compared with two conventional methods on simulated and real data. Results of the simulated and real data sets show that the IBCF technique was slightly better in terms of prediction accuracy than the two conventional methods and the MF method when the correlation was moderately high. The IBCF technique is very attractive because it produces good predictions when there is high correlation between items (environment-trait combinations) and its implementation is computationally feasible, which can be useful for plant breeders who deal with very large data sets. Copyright © 2018 Montesinos-Lopez et al.

  11. Prediction of Multiple-Trait and Multiple-Environment Genomic Data Using Recommender Systems

    Osval A. Montesinos-López

    2018-01-01

    Full Text Available In genomic-enabled prediction, the task of improving the accuracy of the prediction of lines in environments is difficult because the available information is generally sparse and usually has low correlations between traits. In current genomic selection, although researchers have a large amount of information and appropriate statistical models to process it, there is still limited computing efficiency to do so. Although some statistical models are usually mathematically elegant, many of them are also computationally inefficient, and they are impractical for many traits, lines, environments, and years because they need to sample from huge normal multivariate distributions. For these reasons, this study explores two recommender systems: item-based collaborative filtering (IBCF and the matrix factorization algorithm (MF in the context of multiple traits and multiple environments. The IBCF and MF methods were compared with two conventional methods on simulated and real data. Results of the simulated and real data sets show that the IBCF technique was slightly better in terms of prediction accuracy than the two conventional methods and the MF method when the correlation was moderately high. The IBCF technique is very attractive because it produces good predictions when there is high correlation between items (environment–trait combinations and its implementation is computationally feasible, which can be useful for plant breeders who deal with very large data sets.

  12. Small heat shock protein αA-crystallin prevents photoreceptor degeneration in experimental autoimmune uveitis.

    Narsing A Rao

    Full Text Available The small heat shock protein, αA-crystallin null (αA-/- mice are known to be more prone to retinal degeneration than the wild type mice in Experimental Autoimmune Uveoretinitis (EAU. In this report we demonstrate that intravenous administration of αA preserves retinal architecture and prevents photoreceptor damage in EAU. Interestingly, only αA and not αB-crystallin (αB, a closely related small heat shock protein works, pointing to molecular specificity in the observed retinal protection. The possible involvement of αA in retinal protection through immune modulation is corroborated by adaptive transfer experiments, (employing αA-/- and wild type mice with EAU as donors and Rag2-/- as the recipient mice, which indicate that αA protects against the autoimmune challenge by modulating the systemic B and T cell immunity. We show that αA administration causes marked reduction in Th1 cytokines (TNF-α, IL-12 and IFN-γ, both in the retina and in the spleen; notably, IL-17 was only reduced in the retina suggesting local intervention. Importantly, expression of Toll-like receptors and their associated adaptors is also inhibited suggesting that αA protection, against photoreceptor loss in EAU, is associated with systemic suppression of both the adaptive and innate immune responses.

  13. Small heat shock protein αA-crystallin prevents photoreceptor degeneration in experimental autoimmune uveitis.

    Rao, Narsing A; Saraswathy, Sindhu; Pararajasegaram, Geeta; Bhat, Suraj P

    2012-01-01

    The small heat shock protein, αA-crystallin null (αA-/-) mice are known to be more prone to retinal degeneration than the wild type mice in Experimental Autoimmune Uveoretinitis (EAU). In this report we demonstrate that intravenous administration of αA preserves retinal architecture and prevents photoreceptor damage in EAU. Interestingly, only αA and not αB-crystallin (αB), a closely related small heat shock protein works, pointing to molecular specificity in the observed retinal protection. The possible involvement of αA in retinal protection through immune modulation is corroborated by adaptive transfer experiments, (employing αA-/- and wild type mice with EAU as donors and Rag2-/- as the recipient mice), which indicate that αA protects against the autoimmune challenge by modulating the systemic B and T cell immunity. We show that αA administration causes marked reduction in Th1 cytokines (TNF-α, IL-12 and IFN-γ), both in the retina and in the spleen; notably, IL-17 was only reduced in the retina suggesting local intervention. Importantly, expression of Toll-like receptors and their associated adaptors is also inhibited suggesting that αA protection, against photoreceptor loss in EAU, is associated with systemic suppression of both the adaptive and innate immune responses.

  14. Calcium channel-dependent molecular maturation of photoreceptor synapses.

    Nawal Zabouri

    Full Text Available Several studies have shown the importance of calcium channels in the development and/or maturation of synapses. The Ca(V1.4(α(1F knockout mouse is a unique model to study the role of calcium channels in photoreceptor synapse formation. It features abnormal ribbon synapses and aberrant cone morphology. We investigated the expression and targeting of several key elements of ribbon synapses and analyzed the cone morphology in the Ca(V1.4(α(1F knockout retina. Our data demonstrate that most abnormalities occur after eye opening. Indeed, scaffolding proteins such as Bassoon and RIM2 are properly targeted at first, but their expression and localization are not maintained in adulthood. This indicates that either calcium or the Ca(V1.4 channel, or both are necessary for the maintenance of their normal expression and distribution in photoreceptors. Other proteins, such as Veli3 and PSD-95, also display abnormal expression in rods prior to eye opening. Conversely, vesicle related proteins appear normal. Our data demonstrate that the Ca(V1.4 channel is important for maintaining scaffolding proteins in the ribbon synapse but less vital for proteins related to vesicular release. This study also confirms that in adult retinae, cones show developmental features such as sprouting and synaptogenesis. Overall we present evidence that in the absence of the Ca(V1.4 channel, photoreceptor synapses remain immature and are unable to stabilize.

  15. Calcium channel-dependent molecular maturation of photoreceptor synapses.

    Zabouri, Nawal; Haverkamp, Silke

    2013-01-01

    Several studies have shown the importance of calcium channels in the development and/or maturation of synapses. The Ca(V)1.4(α(1F)) knockout mouse is a unique model to study the role of calcium channels in photoreceptor synapse formation. It features abnormal ribbon synapses and aberrant cone morphology. We investigated the expression and targeting of several key elements of ribbon synapses and analyzed the cone morphology in the Ca(V)1.4(α(1F)) knockout retina. Our data demonstrate that most abnormalities occur after eye opening. Indeed, scaffolding proteins such as Bassoon and RIM2 are properly targeted at first, but their expression and localization are not maintained in adulthood. This indicates that either calcium or the Ca(V)1.4 channel, or both are necessary for the maintenance of their normal expression and distribution in photoreceptors. Other proteins, such as Veli3 and PSD-95, also display abnormal expression in rods prior to eye opening. Conversely, vesicle related proteins appear normal. Our data demonstrate that the Ca(V)1.4 channel is important for maintaining scaffolding proteins in the ribbon synapse but less vital for proteins related to vesicular release. This study also confirms that in adult retinae, cones show developmental features such as sprouting and synaptogenesis. Overall we present evidence that in the absence of the Ca(V)1.4 channel, photoreceptor synapses remain immature and are unable to stabilize.

  16. Charging system with galvanic isolation and multiple operating modes

    Kajouke, Lateef A.; Perisic, Milun; Ransom, Ray M.

    2013-01-08

    Systems and methods are provided for operating a charging system with galvanic isolation adapted for multiple operating modes. A vehicle charging system comprises a DC interface, an AC interface, a first conversion module coupled to the DC interface, and a second conversion module coupled to the AC interface. An isolation module is coupled between the first conversion module and the second conversion module. The isolation module comprises a transformer and a switching element coupled between the transformer and the second conversion module. The transformer and the switching element are cooperatively configured for a plurality of operating modes, wherein each operating mode of the plurality of operating modes corresponds to a respective turns ratio of the transformer.

  17. Multiple brain atlas database and atlas-based neuroimaging system.

    Nowinski, W L; Fang, A; Nguyen, B T; Raphel, J K; Jagannathan, L; Raghavan, R; Bryan, R N; Miller, G A

    1997-01-01

    For the purpose of developing multiple, complementary, fully labeled electronic brain atlases and an atlas-based neuroimaging system for analysis, quantification, and real-time manipulation of cerebral structures in two and three dimensions, we have digitized, enhanced, segmented, and labeled the following print brain atlases: Co-Planar Stereotaxic Atlas of the Human Brain by Talairach and Tournoux, Atlas for Stereotaxy of the Human Brain by Schaltenbrand and Wahren, Referentially Oriented Cerebral MRI Anatomy by Talairach and Tournoux, and Atlas of the Cerebral Sulci by Ono, Kubik, and Abernathey. Three-dimensional extensions of these atlases have been developed as well. All two- and three-dimensional atlases are mutually preregistered and may be interactively registered with an actual patient's data. An atlas-based neuroimaging system has been developed that provides support for reformatting, registration, visualization, navigation, image processing, and quantification of clinical data. The anatomical index contains about 1,000 structures and over 400 sulcal patterns. Several new applications of the brain atlas database also have been developed, supported by various technologies such as virtual reality, the Internet, and electronic publishing. Fusion of information from multiple atlases assists the user in comprehensively understanding brain structures and identifying and quantifying anatomical regions in clinical data. The multiple brain atlas database and atlas-based neuroimaging system have substantial potential impact in stereotactic neurosurgery and radiotherapy by assisting in visualization and real-time manipulation in three dimensions of anatomical structures, in quantitative neuroradiology by allowing interactive analysis of clinical data, in three-dimensional neuroeducation, and in brain function studies.

  18. The role of information system in multiple sclerosis management.

    Ajami, Sima; Ahmadi, Golchehreh; Etemadifar, Masoud

    2014-12-01

    Multiple sclerosis (MS) is a chronic disease of central nervous system. The multiple sclerosis information system (MSIS), such as other information system (IS), depends on identification, collection and processing of data for producing useful information. Lack of the integrated IS for collecting standard data causes undesirable effects on exchanging, comparing, and managing. The aim of this study was to recognize the role of the IS in the MS management and determine the advantages and barriers in implementing of the MSIS. The present study was a nonsystematized review that was done in order to recognize the role of the IS in the MS management. In this study, electronic scientific resources such as scientific magazines and books and published topics at conferences were used. We used key words (IS, chronic disease management, and multiple sclerosis), their combination or their synonyms in title, key words, abstracts, and text of English articles and published reports from 1980 until 2013, and by using search engines such as Google, Google Scholar and scientific databases and electronic issues such as iPubMed, sufficiently important difference, Scopus, Medlib, and Magiran for gathering information. More than 200 articles and reports were collected and assessed and 139 of them. Findings showed that the MSIS can reduce of disease expenses through continuously collecting correct, accurate, sufficient, and timely patients and disease nature information; recoding; editing; processing; exchanging, and distributing among different health care centers. Although the MSIS has many advantages; but, we cannot ignore cultural, economic, technical, organizational, and managerial barriers. Therefore, it is necessary to do studies for preventing, reducing, and controlling them. One of the ways is to recognize the advantages of the MSIS and usage information technology in optimizing disease management.

  19. A color based face detection system using multiple templates

    王涛; 卜佳俊; 陈纯

    2003-01-01

    A color based system using multiple templates was developed and implemented for detecting human faces in color images. The algorithm consists of three image processing steps. The first step is human skin color statistics. Then it separates skin regions from non-skin regions. After that, it locates the frontal human face(s) within the skin regions. In the first step, 250 skin samples from persons of different ethnicities are used to determine the color distribution of human skin in chromatic color space in order to get a chroma chart showing likelihoods of skin colors. This chroma chart is used to generate, from the original color image, a gray scale image whose gray value at a pixel shows its likelihood of representing the skin. The algorithm uses an adaptive thresholding process to achieve the optimal threshold value for dividing the gray scale image into separate skin regions from non skin regions. Finally, multiple face templates matching is used to determine if a given skin region represents a frontal human face or not. Test of the system with more than 400 color images showed that the resulting detection rate was 83%, which is better than most color-based face detection systems. The average speed for face detection is 0.8 second/image (400×300 pixels) on a Pentium 3 (800MHz) PC.

  20. Multiprocessor system with multiple concurrent modes of execution

    Ahn, Daniel; Ceze, Luis H; Chen, Dong; Gara, Alan; Heidelberger, Philip; Ohmacht, Martin

    2013-12-31

    A multiprocessor system supports multiple concurrent modes of speculative execution. Speculation identification numbers (IDs) are allocated to speculative threads from a pool of available numbers. The pool is divided into domains, with each domain being assigned to a mode of speculation. Modes of speculation include TM, TLS, and rollback. Allocation of the IDs is carried out with respect to a central state table and using hardware pointers. The IDs are used for writing different versions of speculative results in different ways of a set in a cache memory.

  1. Pareto-Zipf law in growing systems with multiplicative interactions

    Ohtsuki, Toshiya; Tanimoto, Satoshi; Sekiyama, Makoto; Fujihara, Akihiro; Yamamoto, Hiroshi

    2018-06-01

    Numerical simulations of multiplicatively interacting stochastic processes with weighted selections were conducted. A feedback mechanism to control the weight w of selections was proposed. It becomes evident that when w is moderately controlled around 0, such systems spontaneously exhibit the Pareto-Zipf distribution. The simulation results are universal in the sense that microscopic details, such as parameter values and the type of control and weight, are irrelevant. The central ingredient of the Pareto-Zipf law is argued to be the mild control of interactions.

  2. Reward-related learning via multiple memory systems.

    Delgado, Mauricio R; Dickerson, Kathryn C

    2012-07-15

    The application of a neuroeconomic approach to the study of reward-related processes has provided significant insights in our understanding of human learning and decision making. Much of this research has focused primarily on the contributions of the corticostriatal circuitry, involved in trial-and-error reward learning. As a result, less consideration has been allotted to the potential influence of different neural mechanisms such as the hippocampus or to more common ways in human society in which information is acquired and utilized to reach a decision, such as through explicit instruction rather than trial-and-error learning. This review examines the individual contributions of multiple learning and memory neural systems and their interactions during human decision making in both normal and neuropsychiatric populations. Specifically, the anatomical and functional connectivity across multiple memory systems are highlighted to suggest that probing the role of the hippocampus and its interactions with the corticostriatal circuitry via the application of model-based neuroeconomic approaches may provide novel insights into neuropsychiatric populations that suffer from damage to one of these structures and as a consequence have deficits in learning, memory, or decision making. Copyright © 2012 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  3. A color based face detection system using multiple templates

    王涛; 卜佳酸; 陈纯

    2003-01-01

    A color based system using multiple templates was developed and implemented for detecting hu-man faces in color images.The algorithm comsists of three image processing steps.The first step is human skin color statistics.Then it separates skin regions from non-skin regions.After that,it locates the frontal human face(s) within the skin regions.In the first step,250 skin samples from persons of different ethnicities are used to determine the color distribution of human skin in chromatic color space in order to get a chroma chart showing likelihoods of skin colors.This chroma chart is used to generate,from the original color image,a gray scale image whose gray value at a pixel shows its likelihood of representing the shin,The algorithm uses an adaptive thresholding process to achieve the optimal threshold value for dividing the gray scale image into sep-arate skin regions from non skin regions.Finally,multiple face templates matching is used to determine if a given skin region represents a frontal human face or not.Test of the system with more than 400 color images showed that the resulting detection rate was 83%,which is better than most colou-based face detection sys-tems.The average speed for face detection is 0.8 second/image(400×300pixels) on a Pentium 3(800MHz) PC.

  4. Emotional Arousal and Multiple Memory Systems in the Mammalian Brain

    Mark G. Packard

    2012-03-01

    Full Text Available Emotional arousal induced by stress and/or anxiety can exert complex effects on learning and memory processes in mammals. Recent studies have begun to link study of the influence of emotional arousal on memory with earlier research indicating that memory is organized in multiple systems in the brain that differ in terms of the type of memory they mediate. Specifically, these studies have examined whether emotional arousal may have a differential effect on the cognitive and stimulus-response habit memory processes subserved by the hippocampus and dorsal striatum, respectively. Evidence indicates that stress or the peripheral injection of anxiogenic drugs can bias animals and humans towards the use of striatal-dependent habit memory in dual-solution tasks in which both hippocampal and stritatal-based strategies can provide an adequate solution. A bias towards the use of habit memory can also be produced by intra-basolateral amygdala administration of anxiogenic drugs, consistent with the well documented role of efferent projections of this brain region in mediating the modulatory influence of emotional arousal on memory. In some learning situations, the bias towards the use of habit memory produced by emotional arousal appears to result from an impairing effect on hippocampus-dependent cognitive memory. Further research examining the neural mechanisms linking emotion and the relative use of multiple memory systems should prove useful in view of the potential role for maladaptive habitual behaviors in various human psychopathologies.

  5. Multiple single-element transducer photoacoustic computed tomography system

    Kalva, Sandeep Kumar; Hui, Zhe Zhi; Pramanik, Manojit

    2018-02-01

    Light absorption by the chromophores (hemoglobin, melanin, water etc.) present in any biological tissue results in local temperature rise. This rise in temperature results in generation of pressure waves due to the thermoelastic expansion of the tissue. In a circular scanning photoacoustic computed tomography (PACT) system, these pressure waves can be detected using a single-element ultrasound transducer (SUST) (while rotating in full 360° around the sample) or using a circular array transducer. SUST takes several minutes to acquire the PA data around the sample whereas the circular array transducer takes only a fraction of seconds. Hence, for real time imaging circular array transducers are preferred. However, these circular array transducers are custom made, expensive and not easily available in the market whereas SUSTs are cheap and readily available in the market. Using SUST for PACT systems is still cost effective. In order to reduce the scanning time to few seconds instead of using single SUST (rotating 360° ), multiple SUSTs can be used at the same time to acquire the PA data. This will reduce the scanning time by two-fold in case of two SUSTs (rotating 180° ) or by four-fold and eight-fold in case of four SUSTs (rotating 90° ) and eight SUSTs (rotating 45° ) respectively. Here we show that with multiple SUSTs, similar PA images (numerical and experimental phantom data) can be obtained as that of PA images obtained using single SUST.

  6. Democratizing rendering for multiple viewers in surround VR systems

    Schulze, Jürgen P.

    2012-03-01

    We present a new approach for how multiple users\\' views can be rendered in a surround virtual environment without using special multi-view hardware. It is based on the idea that different parts of the screen are often viewed by different users, so that they can be rendered from their own view point, or at least from a point closer to their view point than traditionally expected. The vast majority of 3D virtual reality systems are designed for one head-tracked user, and a number of passive viewers. Only the head tracked user gets to see the correct view of the scene, everybody else sees a distorted image. We reduce this problem by algorithmically democratizing the rendering view point among all tracked users. Researchers have proposed solutions for multiple tracked users, but most of them require major changes to the display hardware of the VR system, such as additional projectors or custom VR glasses. Our approach does not require additional hardware, except the ability to track each participating user. We propose three versions of our multi-viewer algorithm. Each of them balances image distortion and frame rate in different ways, making them more or less suitable for certain application scenarios. Our most sophisticated algorithm renders each pixel from its own, optimized camera perspective, which depends on all tracked users\\' head positions and orientations. © 2012 IEEE.

  7. Democratizing rendering for multiple viewers in surround VR systems

    Schulze, Jü rgen P.; Acevedo-Feliz, Daniel; Mangan, John; Prudhomme, Andrew; Nguyen, Phi Khanh; Weber, Philip P.

    2012-01-01

    We present a new approach for how multiple users' views can be rendered in a surround virtual environment without using special multi-view hardware. It is based on the idea that different parts of the screen are often viewed by different users, so that they can be rendered from their own view point, or at least from a point closer to their view point than traditionally expected. The vast majority of 3D virtual reality systems are designed for one head-tracked user, and a number of passive viewers. Only the head tracked user gets to see the correct view of the scene, everybody else sees a distorted image. We reduce this problem by algorithmically democratizing the rendering view point among all tracked users. Researchers have proposed solutions for multiple tracked users, but most of them require major changes to the display hardware of the VR system, such as additional projectors or custom VR glasses. Our approach does not require additional hardware, except the ability to track each participating user. We propose three versions of our multi-viewer algorithm. Each of them balances image distortion and frame rate in different ways, making them more or less suitable for certain application scenarios. Our most sophisticated algorithm renders each pixel from its own, optimized camera perspective, which depends on all tracked users' head positions and orientations. © 2012 IEEE.

  8. Inference and learning in sparse systems with multiple states

    Braunstein, A.; Ramezanpour, A.; Zhang, P.; Zecchina, R.

    2011-01-01

    We discuss how inference can be performed when data are sampled from the nonergodic phase of systems with multiple attractors. We take as a model system the finite connectivity Hopfield model in the memory phase and suggest a cavity method approach to reconstruct the couplings when the data are separately sampled from few attractor states. We also show how the inference results can be converted into a learning protocol for neural networks in which patterns are presented through weak external fields. The protocol is simple and fully local, and is able to store patterns with a finite overlap with the input patterns without ever reaching a spin-glass phase where all memories are lost.

  9. Autonomic dysfunction in different subtypes of multiple system atrophy.

    Schmidt, Claudia; Herting, Birgit; Prieur, Silke; Junghanns, Susann; Schweitzer, Katherine; Globas, Christoph; Schöls, Ludger; Reichmann, Heinz; Berg, Daniela; Ziemssen, Tjalf

    2008-09-15

    Multiple system atrophy (MSA) can clinically be divided into the cerebellar (MSA-C) and the parkinsonian (MSA-P) variant. However, till now, it is unknown whether autonomic dysfunction in these two entities differs regarding severity and profile. We compared the pattern of autonomic dysfunction in 12 patients with MSA-C and 26 with MSA-P in comparison with 27 age- and sex-matched healthy controls using a standard battery of autonomic function tests and a structured anamnesis of the autonomic nervous system. MSA-P patients complained significantly more often about the symptoms of autonomic dysfunctions than MSA-C patients, especially regarding vasomotor, secretomotor, and gastrointestinal subsystems. However, regarding cardiovascular, sudomotor pupil, urogenital, and sleep subsystems, there were no significant quantitative or qualitative differences as analyzed by autonomic anamnesis and testing. Our results suggest that there are only minor differences in the pattern of autonomic dysfunction between the two clinical MSA phenotypes. (c) 2007 Movement Disorder Society.

  10. The Gas6/TAM System and Multiple Sclerosis.

    Bellan, Mattia; Pirisi, Mario; Sainaghi, Pier Paolo

    2016-10-28

    Growth arrest specific 6 (Gas6) is a multimodular circulating protein, the biological actions of which are mediated by the interaction with three transmembrane tyrosine kinase receptors: Tyro3, Axl, and MerTK, collectively named TAM. Over the last few decades, many progresses have been done in the understanding of the biological activities of this highly pleiotropic system, which plays a role in the regulation of immune response, inflammation, coagulation, cell growth, and clearance of apoptotic bodies. Recent findings have further related Gas6 and TAM receptors to neuroinflammation in general and, specifically, to multiple sclerosis (MS). In this paper, we review the biology of the Gas6/TAM system and the current evidence supporting its potential role in the pathogenesis of MS.

  11. Pineal photoreceptor cells are required for maintaining the circadian rhythms of behavioral visual sensitivity in zebrafish.

    Xinle Li

    Full Text Available In non-mammalian vertebrates, the pineal gland functions as the central pacemaker that regulates the circadian rhythms of animal behavior and physiology. We generated a transgenic zebrafish line [Tg(Gnat2:gal4-VP16/UAS:nfsB-mCherry] in which the E. coli nitroreductase is expressed in pineal photoreceptor cells. In developing embryos and young adults, the transgene is expressed in both retinal and pineal photoreceptor cells. During aging, the expression of the transgene in retinal photoreceptor cells gradually diminishes. By 8 months of age, the Gnat2 promoter-driven nitroreductase is no longer expressed in retinal photoreceptor cells, but its expression in pineal photoreceptor cells persists. This provides a tool for selective ablation of pineal photoreceptor cells, i.e., by treatments with metronidazole. In the absence of pineal photoreceptor cells, the behavioral visual sensitivity of the fish remains unchanged; however, the circadian rhythms of rod and cone sensitivity are diminished. Brief light exposures restore the circadian rhythms of behavioral visual sensitivity. Together, the data suggest that retinal photoreceptor cells respond to environmental cues and are capable of entraining the circadian rhythms of visual sensitivity; however, they are insufficient for maintaining the rhythms. Cellular signals from the pineal photoreceptor cells may be required for maintaining the circadian rhythms of visual sensitivity.

  12. Solution of multiple circuits of steam cycle HTR system

    Li, Fu; Wang, Dengying; Hao, Chen; Zheng, Yanhua

    2014-01-01

    In order to analyze the dynamic operation performance and safety characteristics of the steam cycle high temperature gas cooled reactor (HTR) systems, it is necessary to find the solution of the whole HTR systems with all coupled circuits, including the primary circuit, the secondary circuit, and the residual heat removal system (RHRS). Considering that those circuits have their own individual fluidity and characteristics, some existing code packages for independent circuits themselves have been developed, for example THEMRIX and TINTE code for the primary circuit of the pebble bed reactor, BLAST for once through steam generator. To solve the coupled steam cycle HTR systems, a feasible way is to develop coupling method to integrate these independent code packages. This paper presents several coupling methods, e.g. the equivalent component method between the primary circuit and steam generator which reflect the close coupling relationship, the overlapping domain decomposition method between the primary circuit and the passive RHRS which reflects the loose coupling relationship. Through this way, the whole steam cycle HTR system with multiple circuits can be easily and efficiently solved by integration of several existing code packages. Based on this methodology, a code package TINTE–BLAST–RHRS was developed. Using this code package, some operation performance of HTR–PM was analyzed, such as the start-up process of the plant, and the depressurized loss of forced cooling accident when different number of residual heat removal trains is operated

  13. PhantomNet: Exploring Optimal Multicellular Multiple Antenna Systems

    Foschini Gerard J

    2004-01-01

    Full Text Available We present a network framework for evaluating the theoretical performance limits of wireless data communication. We address the problem of providing the best possible service to new users joining the system without affecting existing users. Since, interference-wise, new users are required to be invisible to existing users, the network is dubbed PhantomNet. The novelty is the generality obtained in this context. Namely, we can deal with multiple users, multiple antennas, and multiple cells on both the uplink and the downlink. The solution for the uplink is effectively the same as for a single cell system since all the base stations (BSs simply amount to one composite BS with centralized processing. The optimum strategy, following directly from known results, is successive decoding (SD, where the new user is decoded before the existing users so that the new users' signal can be subtracted out to meet its invisibility requirement. Only the BS needs to modify its decoding scheme in the handling of new users, since existing users continue to transmit their data exactly as they did before the new arrivals. The downlink, even with the BSs operating as one composite BS, is more problematic. With multiple antennas at each BS site, the optimal coding scheme and the capacity region for this channel are unsolved problems. SD and dirty paper (DP are two schemes previously reported to achieve capacity in special cases. For PhantomNet, we show that DP coding at the BS is equal to or better than SD. The new user is encoded before the existing users so that the interference caused by his signal to existing users is known to the transmitter. Thus the BS modifies its encoding scheme to accommodate new users so that existing users continue to operate as before: they achieve the same rates as before and they decode their signal in precisely the same way as before. The solutions for the uplink and the downlink are particularly interesting in the way they exhibit a

  14. Multiple Scattering in Random Mechanical Systems and Diffusion Approximation

    Feres, Renato; Ng, Jasmine; Zhang, Hong-Kun

    2013-10-01

    This paper is concerned with stochastic processes that model multiple (or iterated) scattering in classical mechanical systems of billiard type, defined below. From a given (deterministic) system of billiard type, a random process with transition probabilities operator P is introduced by assuming that some of the dynamical variables are random with prescribed probability distributions. Of particular interest are systems with weak scattering, which are associated to parametric families of operators P h , depending on a geometric or mechanical parameter h, that approaches the identity as h goes to 0. It is shown that ( P h - I)/ h converges for small h to a second order elliptic differential operator on compactly supported functions and that the Markov chain process associated to P h converges to a diffusion with infinitesimal generator . Both P h and are self-adjoint (densely) defined on the space of square-integrable functions over the (lower) half-space in , where η is a stationary measure. This measure's density is either (post-collision) Maxwell-Boltzmann distribution or Knudsen cosine law, and the random processes with infinitesimal generator respectively correspond to what we call MB diffusion and (generalized) Legendre diffusion. Concrete examples of simple mechanical systems are given and illustrated by numerically simulating the random processes.

  15. A yeast screening system for simultaneously monitoring multiple genetic endpoints

    Dixon, M.L.; Mortimer, R.K.

    1986-01-01

    Mutation, recombination, and mitochondrial deficiencies have been proposed to have roles in the carcinogenic process. The authors describe a diploid strain of the yeast Saccharomyces cerevisiae capable of detecting this wide spectrum of genetic changes. The markers used for monitoring these events have been especially well characterized genetically. Ultraviolet light was chosen as a model carcinogenic agent to test this system. In addition to highly significant increases in the frequencies of each genetic change, increases in the absolute numbers of each change indicated induction and not selective survival. The relative amounts of each type of genetic change varied with dose. The wide spectrum of endpoints monitored in the XD83 yeast system may allow the detection of certain carcinogens and other genetically toxic agents which have escaped detection in more limited systems. Since only one strain is required to simultaneously monitor these genetic changes, this assay system should facilitate comparisons of the induced changes and be more efficient than using multiple strains to monitor the same endpoints. (Auth.)

  16. Supporting Multiple Cognitive Processing Styles Using Tailored Support Systems

    Tuan Q. Tran; Karen M. Feigh; Amy R. Pritchett

    2007-01-01

    According to theories of cognitive processing style or cognitive control mode, human performance is more effective when an individual's cognitive state (e.g., intuition/scramble vs. deliberate/strategic) matches his/her ecological constraints or context (e.g., utilize intuition to strive for a 'good-enough' response instead of deliberating for the 'best' response under high time pressure). Ill-mapping between cognitive state and ecological constraints are believed to lead to degraded task performance. Consequently, incorporating support systems which are designed to specifically address multiple cognitive and functional states e.g., high workload, stress, boredom, and initiate appropriate mitigation strategies (e.g., reduce information load) is essential to reduce plant risk. Utilizing the concept of Cognitive Control Models, this paper will discuss the importance of tailoring support systems to match an operator's cognitive state, and will further discuss the importance of these ecological constraints in selecting and implementing mitigation strategies for safe and effective system performance. An example from the nuclear power plant industry illustrating how a support system might be tailored to support different cognitive states is included

  17. Multiple-scattering in radar systems: A review

    Battaglia, Alessandro; Tanelli, Simone; Kobayashi, Satoru; Zrnic, Dusan; Hogan, Robin J.; Simmer, Clemens

    2010-01-01

    Although extensively studied within the lidar community, the multiple scattering phenomenon has always been considered a rare curiosity by radar meteorologists. Up to few years ago its appearance has only been associated with two- or three-body-scattering features (e.g. hail flares and mirror images) involving highly reflective surfaces. Recent atmospheric research aimed at better understanding of the water cycle and the role played by clouds and precipitation in affecting the Earth's climate has driven the deployment of high frequency radars in space. Examples are the TRMM 13.5 GHz, the CloudSat 94 GHz, the upcoming EarthCARE 94 GHz, and the GPM dual 13-35 GHz radars. These systems are able to detect the vertical distribution of hydrometeors and thus provide crucial feedbacks for radiation and climate studies. The shift towards higher frequencies increases the sensitivity to hydrometeors, improves the spatial resolution and reduces the size and weight of the radar systems. On the other hand, higher frequency radars are affected by stronger extinction, especially in the presence of large precipitating particles (e.g. raindrops or hail particles), which may eventually drive the signal below the minimum detection threshold. In such circumstances the interpretation of the radar equation via the single scattering approximation may be problematic. Errors will be large when the radiation emitted from the radar after interacting more than once with the medium still contributes substantially to the received power. This is the case if the transport mean-free-path becomes comparable with the instrument footprint (determined by the antenna beam-width and the platform altitude). This situation resembles to what has already been experienced in lidar observations, but with a predominance of wide- versus small-angle scattering events. At millimeter wavelengths, hydrometeors diffuse radiation rather isotropically compared to the visible or near infrared region where scattering is

  18. State estimation of chemical engineering systems tending to multiple solutions

    N. P. G. Salau

    2014-09-01

    Full Text Available A well-evaluated state covariance matrix avoids error propagation due to divergence issues and, thereby, it is crucial for a successful state estimator design. In this paper we investigate the performance of the state covariance matrices used in three unconstrained Extended Kalman Filter (EKF formulations and one constrained EKF formulation (CEKF. As benchmark case studies we have chosen: a a batch chemical reactor with reversible reactions whose system model and measurement are such that multiple states satisfy the equilibrium condition and b a CSTR with exothermic irreversible reactions and cooling jacket energy balance whose nonlinear behavior includes multiple steady-states and limit cycles. The results have shown that CEKF is in general the best choice of EKF formulations (even if they are constrained with an ad hoc clipping strategy which avoids undesired states for such case studies. Contrary to a clipped EKF formulation, CEKF incorporates constraints into an optimization problem, which minimizes the noise in a least square sense preventing a bad noise distribution. It is also shown that, although the Moving Horizon Estimation (MHE provides greater robustness to a poor guess of the initial state, converging in less steps to the actual states, it is not justified for our examples due to the high additional computational effort.

  19. Mechanism of immune suppression by ultraviolet irradiation in vivo. I. Evidence for the existence of a unique photoreceptor in skin and its role in photoimmunology

    De Fabo, E.C.; Noonan, F.P.

    1983-01-01

    UV irradiation of mice causes a systemic immune alteration that can be detected either by suppression of the immunologic rejection of UV-induced tumors, or by suppression of contact hypersensitivity (CHS). Suppression of these two immunologic responses has similar photobiologic characteristics and in both cases is associated with the generation of antigen-specific suppressor T cells. To identify whether a specific photoreceptor for this effect exists, the relative wavelength effectiveness (action spectrum) was determined for the UV-induced suppression of CHS. Narrow bands of UV (half bandwidth 3 nm) were used at 10 wavelengths from 250 to 320 nm to obtain dose-response curves. The action spectrum derived from the dose-response curves has a maximum between 260 and 270 nm, a shoulder at 280-290 nm, and declines steadily to approximately 3% of maximum at 320 nm. The finding of such a clearly defined wavelength dependence implies the presence of a specific photoreceptor for this effect. Removing the stratum corneum by tape stripping before UV irradiation prevented the suppression of CHS using 254-nm radiation, suggesting the photoreceptor is superficially located in the skin. The hypothesis is advanced that the photoreceptor for systemic UV-induced immunosuppression of contact hypersensitivity may be urocanic acid. As such, it may also play a role in UV-induced carcinogenesis via the production of tumor-specific suppressor cells

  20. Recommendations of the Global Multiple System Atrophy Research Roadmap Meeting.

    Walsh, Ryan R; Krismer, Florian; Galpern, Wendy R; Wenning, Gregor K; Low, Phillip A; Halliday, Glenda; Koroshetz, Walter J; Holton, Janice; Quinn, Niall P; Rascol, Olivier; Shaw, Leslie M; Eidelberg, David; Bower, Pam; Cummings, Jeffrey L; Abler, Victor; Biedenharn, Judy; Bitan, Gal; Brooks, David J; Brundin, Patrik; Fernandez, Hubert; Fortier, Philip; Freeman, Roy; Gasser, Thomas; Hewitt, Art; Höglinger, Günter U; Huentelman, Matt J; Jensen, Poul H; Jeromin, Andreas; Kang, Un Jung; Kaufmann, Horacio; Kellerman, Lawrence; Khurana, Vikram; Klockgether, Thomas; Kim, Woojin Scott; Langer, Carol; LeWitt, Peter; Masliah, Eliezer; Meissner, Wassilios; Melki, Ronald; Ostrowitzki, Susanne; Piantadosi, Steven; Poewe, Werner; Robertson, David; Roemer, Cyndi; Schenk, Dale; Schlossmacher, Michael; Schmahmann, Jeremy D; Seppi, Klaus; Shih, Lily; Siderowf, Andrew; Stebbins, Glenn T; Stefanova, Nadia; Tsuji, Shoji; Sutton, Sharon; Zhang, Jing

    2018-01-09

    Multiple system atrophy (MSA) is a rare neurodegenerative disorder with substantial knowledge gaps despite recent gains in basic and clinical research. In order to make further advances, concerted international collaboration is vital. In 2014, an international meeting involving leaders in the field and MSA advocacy groups was convened in Las Vegas, Nevada, to identify critical research areas where consensus and progress was needed to improve understanding, diagnosis, and treatment of the disease. Eight topic areas were defined: pathogenesis, preclinical modeling, target identification, endophenotyping, clinical measures, imaging biomarkers, nonimaging biomarkers, treatments/trial designs, and patient advocacy. For each topic area, an expert served as a working group chair and each working group developed priority-ranked research recommendations with associated timelines and pathways to reach the intended goals. In this report, each groups' recommendations are provided. Copyright © 2017 American Academy of Neurology.

  1. Role of kinesin heavy chain in Crumbs localization along the rhabdomere elongation in Drosophila photoreceptor.

    Garrett P League

    Full Text Available BACKGROUND: Crumbs (Crb, a cell polarity gene, has been shown to provide a positional cue for the extension of the apical membrane domain, adherens junction (AJ, and rhabdomere along the growing proximal-distal axis during Drosophila photoreceptor morphogenesis. In developing Drosophila photoreceptors, a stabilized microtubule structure was discovered and its presence was linked to polarity protein localization. It was therefore hypothesized that the microtubules may provide trafficking routes for the polarity proteins during photoreceptor morphogenesis. This study has examined whether Kinesin heavy chain (Khc, a subunit of the microtubule-based motor Kinesin-1, is essential in polarity protein localization in developing photoreceptors. METHODOLOGY/PRINCIPAL FINDINGS: Because a genetic interaction was found between crb and khc, Crb localization was examined in the developing photoreceptors of khc mutants. khc was dispensable during early eye differentiation and development. However, khc mutant photoreceptors showed a range of abnormalities in the apical membrane domain depending on the position along the proximal-distal axis in pupal photoreceptors. The khc mutant showed a progressive mislocalization in the apical domain along the distal-proximal axis during rhabdomere elongation. The khc mutation also led to a similar progressive defect in the stabilized microtubule structures, strongly suggesting that Khc is essential for microtubule structure and Crb localization during distal to proximal rhabdomere elongation in pupal morphogenesis. This role of Khc in apical domain control was further supported by khc's gain-of-function phenotype. Khc overexpression in photoreceptors caused disruption of the apical membrane domain and the stabilized microtubules in the developing photoreceptors. CONCLUSIONS/SIGNIFICANCE: In summary, we examined the role of khc in the regulation of the apical Crb domain in developing photoreceptors. Since the rhabdomeres in

  2. Transient well flow in leaky multiple-aquifer systems

    Hemker, C. J.

    1985-10-01

    A previously developed eigenvalue analysis approach to groundwater flow in leaky multiple aquifers is used to derive exact solutions for transient well flow problems in leaky and confined systems comprising any number of aquifers. Equations are presented for the drawdown distribution in systems of infinite extent, caused by wells penetrating one or more of the aquifers completely and discharging each layer at a constant rate. Since the solution obtained may be regarded as a combined analytical-numerical technique, a type of one-dimensional modelling can be applied to find approximate solutions for several complicating conditions. Numerical evaluations are presented as time-drawdown curves and include effects of storage in the aquitard, unconfined conditions, partially penetrating wells and stratified aquifers. The outcome of calculations for relatively simple systems compares very well with published corresponding results. The proposed multilayer solution can be a valuable tool in aquifer test evaluation, as it provides the analytical expression required to enable the application of existing computer methods to the determination of aquifer characteristics.

  3. Comparison of DVH data from multiple radiotherapy treatment planning systems

    Ebert, M A; Kearvell, R; Hooton, B; Spry, N A; Bydder, S A; Joseph, D J; Haworth, A; Hug, B

    2010-01-01

    This study examined the variation of dose-volume histogram (DVH) data sourced from multiple radiotherapy treatment planning systems (TPSs). Treatment plan exports were obtained from 33 Australian and New Zealand centres during a dosimetry study. Plan information, including DVH data, was exported from the TPS at each centre and reviewed in a digital review system (SWAN). The review system was then used to produce an independent calculation of DVH information for each delineated structure. The relationships between DVHs extracted from each TPS and independently calculated were examined, particularly in terms of the influence of CT scan slice and pixel widths, the resolution of dose calculation grids and the TPS manufacturer. Calculation of total volume and DVH data was consistent between SWAN and each TPS, with the small discrepancies found tending to increase with decreasing structure size. This was significantly influenced by the TPS model used to derive the data. For target structures covered with relatively uniform dose distributions, there was a significant difference between the minimum dose in each TPS-exported DVH and that calculated independently. (note)

  4. Multiple Interests of Users in Collaborative Tagging Systems

    Au Yeung, Ching-Man; Gibbins, Nicholas; Shadbolt, Nigel

    Performance of recommender systems depends on whether the user profiles contain accurate information about the interests of the users, and this in turn relies on whether enough information about their interests can be collected. Collaborative tagging systems allow users to use their own words to describe their favourite resources, resulting in some user-generated categorisation schemes commonly known as folksonomies. Folksonomies thus contain rich information about the interests of the users, which can be used to support various recommender systems. Our analysis of the folksonomy in Delicious reveals that the interests of a single user can be very diverse. Traditional methods for representing interests of users are usually not able to reflect such diversity. We propose a method to construct user profiles of multiple interests from folksonomies based on a network clustering technique. Our evaluation shows that the proposed method is able to generate user profiles which reflect the diversity of user interests and can be used as a basis of providing more focused recommendation to the users.

  5. Light adaptation and the evolution of vertebrate photoreceptors.

    Morshedian, Ala; Fain, Gordon L

    2017-07-15

    Lamprey are cyclostomes, a group of vertebrates that diverged from lines leading to jawed vertebrates (including mammals) in the late Cambrian, 500 million years ago. It may therefore be possible to infer properties of photoreceptors in early vertebrate progenitors by comparing lamprey to other vertebrates. We show that lamprey rods and cones respond to light much like rods and cones in amphibians and mammals. They operate over a similar range of light intensities and adapt to backgrounds and bleaches nearly identically. These correspondences are pervasive and detailed; they argue for the presence of rods and cones very early in the evolution of vertebrates with properties much like those of rods and cones in existing vertebrate species. The earliest vertebrates were agnathans - fish-like organisms without jaws, which first appeared near the end of the Cambrian radiation. One group of agnathans became cyclostomes, which include lamprey and hagfish. Other agnathans gave rise to jawed vertebrates or gnathostomes, the group including all other existing vertebrate species. Because cyclostomes diverged from other vertebrates 500 million years ago, it may be possible to infer some of the properties of the retina of early vertebrate progenitors by comparing lamprey to other vertebrates. We have previously shown that rods and cones in lamprey respond to light much like photoreceptors in other vertebrates and have a similar sensitivity. We now show that these affinities are even closer. Both rods and cones adapt to background light and to bleaches in a manner almost identical to other vertebrate photoreceptors. The operating range in darkness is nearly the same in lamprey and in amphibian or mammalian rods and cones; moreover background light shifts response-intensity curves downward and to the right over a similar range of ambient intensities. Rods show increment saturation at about the same intensity as mammalian rods, and cones never saturate. Bleaches decrease

  6. A Multiple-Channel Sub-Band Transient Detection System

    David A. Smith

    1998-11-01

    We have developed a unique multiple-channel sub-band transient detection system to record transient electromagnetic signals in carrier-dominated radio environments; the system has been used to make unique observations of weak, transient HF signals. The detection system has made these observations possible through improved sensitivity compared to conventional broadband transient detection systems; the sensitivity improvement is estimated to be at least 20 dB. The increase in sensitivity has been achieved through subdivision of the band of interest (an 18 MHz tunable bandwidth) into eight sub-band independent detection channels, each with a 400 kHz bandwidth and its own criteria. The system generates a system trigger signal when a predetermined number of channels (typically five) trigger within a predetermined window of time (typically 100 ~s). Events are recorded with a broadband data acquisition system sampling at 50 or 100 Msample/s, so despite the fact that the detection system operates on portions of the signal confined to narrow bands, data acquisition is broadband. Between May and September of 1994, the system was used to detect and record over six thousand transient events in the frequency band from 3 to 30 MHz. Approximately 500 of the events have been characterized as paired bursts of radio noise with individual durations of 2 to 10 ps and separations between the bursts of 5 to 160 ps. The paired transients are typically 5 to 40 dB brighter than the background electromagnetic spectrum between carrier signals. We have termed these events SubIonospheric Pulse Pairs (SIPPS) and presently have no explanation as to their source. Our observations of SIPPS resemble observations of TransIonospheric Pulse Pairs (TIPPs) recorded by the Blackboard instrument on the ALEXIS satellite; the source of TIPP events is also unknown. Most of the recorded SIPP events do not exhibit frequency dispersion, implying propagation along a line-of-sight (groundwave) path; but seven of

  7. Music recommendation system for biofied building considering multiple residents

    Ito, Takahiro; Mita, Akira

    2012-04-01

    This research presents a music recommendation system based on multiple users' communication excitement and productivity. Evaluation is conducted on following two points. 1, Does songA recommended by the system improve the situation of dropped down communication excitement? 2, Does songB recommended by the system improve the situation of dropped down and productivity of collaborative work? The objective of this system is to recommend songs which shall improve the situation of dropped down communication excitement and productivity. Songs are characterized according to three aspects; familiarity, relaxing and BPM(Beat Per Minutes). Communication excitement is calculated from speech data obtained by an audio sensor. Productivity of collaborative brainstorming is manually calculated by the number of time-series key words during mind mapping. First experiment was music impression experiment to 118 students. Based on 1, average points of familiarity, relaxing and BPM 2, cronbach alpha factor, songA(high familiarity, high relaxing and high BPM song) and songB(high familiarity, high relaxing and low BPM) are selected. Exploratory experiment defined dropped down communication excitement and dropped down and productivity of collaborative work. Final experiment was conducted to 32 first meeting students divided into 8 groups. First 4 groups had mind mapping 1 while listening to songA, then had mind mapping 2 while listening songB. Following 4 groups had mind mapping 1 while listening to songB, then had mind mapping 2 while listening songA. Fianl experiment shows two results. Firstly, ratio of communication excitement between music listening section and whole brain storming is 1.27. Secondly, this system increases 69% of average productivity.

  8. Evaluating accounting information systems that support multiple GAAP reporting using Normalized Systems Theory

    Vanhoof, E.; Huysmans, P.; Aerts, Walter; Verelst, J.; Aveiro, D.; Tribolet, J.; Gouveia, D.

    2014-01-01

    This paper uses a mixed methods approach of design science and case study research to evaluate structures of Accounting Information Systems (AIS) that report in multiple Generally Accepted Accounting Principles (GAAP), using Normalized Systems Theory (NST). To comply with regulation, many companies

  9. Evidence for dynamic network regulation of Drosophila photoreceptor function from mutants lacking the neurotransmitter histamine

    An eDau

    2016-03-01

    Full Text Available Synaptic feedback from interneurons to photoreceptors can help to optimize visual information flow by balancing its allocation on retinal pathways under changing light conditions. But little is known about how this critical network operation is regulated dynamically. Here, we investigate this question by comparing signaling properties and performance of wild-type Drosophila R1-R6 photoreceptors to those of the hdcJK910 mutant, which lacks the neurotransmitter histamine and therefore cannot transmit information to interneurons. Recordings show that hdcJK910 photoreceptors sample similar amounts of information from naturalistic stimulation to wild-type photoreceptors, but this information is packaged in smaller responses, especially under bright illumination. Analyses reveal how these altered dynamics primarily resulted from network overload that affected hdcJK910 photoreceptors in two ways. First, the missing inhibitory histamine input to interneurons almost certainly depolarized them irrevocably, which in turn increased their excitatory feedback to hdcJK910 R1-R6s. This tonic excitation depolarized the photoreceptors to artificially high potentials, reducing their operational range. Second, rescuing histamine input to interneurons in hdcJK910 mutant also restored their normal phasic feedback modulation to R1-R6s, causing photoreceptor output to accentuate dynamic intensity differences at bright illumination, similar to the wild-type. These results provide mechanistic explanations of how synaptic feedback connections optimize information packaging in photoreceptor output and novel insight into the operation and design of dynamic network regulation of sensory neurons.

  10. Modulation of multiple memory systems: from neurotransmitters to metabolic substrates.

    Gold, Paul E; Newman, Lori A; Scavuzzo, Claire J; Korol, Donna L

    2013-11-01

    This article reviews evidence showing that neurochemical modulators can regulate the relative participation of the hippocampus and striatum in learning and memory tasks. For example, relative release of acetylcholine increases in the hippocampus and striatum reflects the relative engagement of these brain systems during learning of place and response tasks. Acetylcholine release is regulated in part by available brain glucose levels, which themselves are dynamically modified during learning. Recent findings suggest that glucose acts through astrocytes to deliver lactate to neurons. Brain glycogen is contained in astrocytes and provides a capacity to deliver energy substrates to neurons when needed, a need that can be generated by training on tasks that target hippocampal and striatal processing mechanisms. These results integrate an increase in blood glucose after epinephrine release from the adrenal medulla with provision of brain energy substrates, including lactate released from astrocytes. Together, the availability of peripheral and central energy substrates regulate the processing of learning and memory within and across multiple neural systems. Dysfunctions of the physiological steps that modulate memory--from hormones to neurotransmitters to metabolic substrates--may contribute importantly to some of the cognitive impairments seen during normal aging and during neurodegenerative diseases. Copyright © 2013 Wiley Periodicals, Inc.

  11. An Advanced N -body Model for Interacting Multiple Stellar Systems

    Brož, Miroslav [Astronomical Institute of the Charles University, Faculty of Mathematics and Physics, V Holešovičkách 2, CZ-18000 Praha 8 (Czech Republic)

    2017-06-01

    We construct an advanced model for interacting multiple stellar systems in which we compute all trajectories with a numerical N -body integrator, namely the Bulirsch–Stoer from the SWIFT package. We can then derive various observables: astrometric positions, radial velocities, minima timings (TTVs), eclipse durations, interferometric visibilities, closure phases, synthetic spectra, spectral energy distribution, and even complete light curves. We use a modified version of the Wilson–Devinney code for the latter, in which the instantaneous true phase and inclination of the eclipsing binary are governed by the N -body integration. If all of these types of observations are at one’s disposal, a joint χ {sup 2} metric and an optimization algorithm (a simplex or simulated annealing) allow one to search for a global minimum and construct very robust models of stellar systems. At the same time, our N -body model is free from artifacts that may arise if mutual gravitational interactions among all components are not self-consistently accounted for. Finally, we present a number of examples showing dynamical effects that can be studied with our code and we discuss how systematic errors may affect the results (and how to prevent this from happening).

  12. Multiple systemic embolism in infective endocarditis underlying in Barlow's disease.

    Yu, Ziqing; Fan, Bing; Wu, Hongyi; Wang, Xiangfei; Li, Chenguang; Xu, Rende; Su, Yangang; Ge, Junbo

    2016-08-11

    Systemic embolism, especially septic embolism, is a severe complication of infective endocarditis (IE). However, concurrent embolism to the brain, coronary arteries, and spleen is very rare. Because of the risk of hemorrhage or visceral rupture, anticoagulants are recommended only if an indication is present, e.g. prosthetic valve. Antiplatelet therapy in IE is controversial, but theoretically, this therapy has the potential to prevent and treat thrombosis and embolism in IE. Unfortunately, clinical trial results have been inconclusive. We describe a previously healthy 50-year-old man who presented with dysarthria secondary to bacterial endocarditis with multiple cerebral, coronary, splenic, and peripheral emboli; antibiotic therapy contributed to the multiple emboli. Emergency splenectomy was performed, with subsequent mitral valve repair. Pathological examination confirmed mucoid degeneration and mitral valve prolapse (Barlow's disease) as the underlying etiology of the endocardial lesion. Continuous antibiotics were prescribed, postoperatively. Transthoracic echocardiography at 1.5, 3, and 6 months after the onset of his illness showed no severe regurgitation, and there was no respiratory distress, fever, or lethargy during follow-up. Although antibiotic use in IE carries a risk of septic embolism, these drugs have bactericidal and antithrombotic benefits. It is important to consider that negative blood culture and symptom resolution do not confirm complete elimination of bacteria. However, vegetation size and Staphylococcus aureus infection accurately predict embolization. It is also important to consider that bacteria can be segregated from the microbicide when embedded in platelets and fibrin. Therefore, antimicrobial therapy with concurrent antiplatelet therapy should be considered carefully.

  13. Photoreceptor processing speed and input resistance changes during light adaptation correlate with spectral class in the bumblebee, Bombus impatiens.

    Peter Skorupski

    Full Text Available Colour vision depends on comparison of signals from photoreceptors with different spectral sensitivities. However, response properties of photoreceptor cells may differ in ways other than spectral tuning. In insects, for example, broadband photoreceptors, with a major sensitivity peak in the green region of the spectrum (>500 nm, drive fast visual processes, which are largely blind to chromatic signals from more narrowly-tuned photoreceptors with peak sensitivities in the blue and UV regions of the spectrum. In addition, electrophysiological properties of the photoreceptor membrane may result in differences in response dynamics of photoreceptors of similar spectral class between species, and different spectral classes within a species. We used intracellular electrophysiological techniques to investigate response dynamics of the three spectral classes of photoreceptor underlying trichromatic colour vision in the bumblebee, Bombus impatiens, and we compare these with previously published data from a related species, Bombus terrestris. In both species, we found significantly faster responses in green, compared with blue- or UV-sensitive photoreceptors, although all 3 photoreceptor types are slower in B. impatiens than in B. terrestris. Integration times for light-adapted B. impatiens photoreceptors (estimated from impulse response half-width were 11.3 ± 1.6 ms for green photoreceptors compared with 18.6 ± 4.4 ms and 15.6 ± 4.4 for blue and UV, respectively. We also measured photoreceptor input resistance in dark- and light-adapted conditions. All photoreceptors showed a decrease in input resistance during light adaptation, but this decrease was considerably larger (declining to about 22% of the dark value in green photoreceptors, compared to blue and UV (41% and 49%, respectively. Our results suggest that the conductances associated with light adaptation are largest in green photoreceptors, contributing to their greater temporal processing speed

  14. System health monitoring using multiple-model adaptive estimation techniques

    Sifford, Stanley Ryan

    Monitoring system health for fault detection and diagnosis by tracking system parameters concurrently with state estimates is approached using a new multiple-model adaptive estimation (MMAE) method. This novel method is called GRid-based Adaptive Parameter Estimation (GRAPE). GRAPE expands existing MMAE methods by using new techniques to sample the parameter space. GRAPE expands on MMAE with the hypothesis that sample models can be applied and resampled without relying on a predefined set of models. GRAPE is initially implemented in a linear framework using Kalman filter models. A more generalized GRAPE formulation is presented using extended Kalman filter (EKF) models to represent nonlinear systems. GRAPE can handle both time invariant and time varying systems as it is designed to track parameter changes. Two techniques are presented to generate parameter samples for the parallel filter models. The first approach is called selected grid-based stratification (SGBS). SGBS divides the parameter space into equally spaced strata. The second approach uses Latin Hypercube Sampling (LHS) to determine the parameter locations and minimize the total number of required models. LHS is particularly useful when the parameter dimensions grow. Adding more parameters does not require the model count to increase for LHS. Each resample is independent of the prior sample set other than the location of the parameter estimate. SGBS and LHS can be used for both the initial sample and subsequent resamples. Furthermore, resamples are not required to use the same technique. Both techniques are demonstrated for both linear and nonlinear frameworks. The GRAPE framework further formalizes the parameter tracking process through a general approach for nonlinear systems. These additional methods allow GRAPE to either narrow the focus to converged values within a parameter range or expand the range in the appropriate direction to track the parameters outside the current parameter range boundary

  15. Designing an Electronic Patient Management System for Multiple Sclerosis: Building a Next Generation Multiple Sclerosis Documentation System.

    Kern, Raimar; Haase, Rocco; Eisele, Judith Christina; Thomas, Katja; Ziemssen, Tjalf

    2016-01-08

    Technologies like electronic health records or telemedicine devices support the rapid mediation of health information and clinical data independent of time and location between patients and their physicians as well as among health care professionals. Today, every part of the treatment process from diagnosis, treatment selection, and application to patient education and long-term care may be enhanced by a quality-assured implementation of health information technology (HIT) that also takes data security standards and concerns into account. In order to increase the level of effectively realized benefits of eHealth services, a user-driven needs assessment should ensure the inclusion of health care professional perspectives into the process of technology development as we did in the development process of the Multiple Sclerosis Documentation System 3D. After analyzing the use of information technology by patients suffering from multiple sclerosis, we focused on the needs of neurological health care professionals and their handling of health information technology. Therefore, we researched the status quo of eHealth adoption in neurological practices and clinics as well as health care professional opinions about potential benefits and requirements of eHealth services in the field of multiple sclerosis. We conducted a paper-and-pencil-based mail survey in 2013 by sending our questionnaire to 600 randomly chosen neurological practices in Germany. The questionnaire consisted of 24 items covering characteristics of participating neurological practices (4 items), the current use of network technology and the Internet in such neurological practices (5 items), physicians' attitudes toward the general and MS-related usefulness of eHealth systems (8 items) and toward the clinical documentation via electronic health records (4 items), and physicians' knowledge about the Multiple Sclerosis Documentation System (3 items). From 600 mailed surveys, 74 completed surveys were returned

  16. An automated algorithm for photoreceptors counting in adaptive optics retinal images

    Liu, Xu; Zhang, Yudong; Yun, Dai

    2012-10-01

    Eyes are important organs of humans that detect light and form spatial and color vision. Knowing the exact number of cones in retinal image has great importance in helping us understand the mechanism of eyes' function and the pathology of some eye disease. In order to analyze data in real time and process large-scale data, an automated algorithm is designed to label cone photoreceptors in adaptive optics (AO) retinal images. Images acquired by the flood-illuminated AO system are taken to test the efficiency of this algorithm. We labeled these images both automatically and manually, and compared the results of the two methods. A 94.1% to 96.5% agreement rate between the two methods is achieved in this experiment, which demonstrated the reliability and efficiency of the algorithm.

  17. Modulation of rod photoreceptor output by HCN1 channels is essential for regular mesopic cone vision.

    Seeliger, Mathias W; Brombas, Arne; Weiler, Reto; Humphries, Peter; Knop, Gabriel; Tanimoto, Naoyuki; Müller, Frank

    2011-11-08

    Retinal photoreceptors permit visual perception over a wide range of lighting conditions. Rods work best in dim, and cones in bright environments, with considerable functional overlap at intermediate (mesopic) light levels. At many sites in the outer and inner retina where rod and cone signals interact, gap junctions, particularly those containing Connexin36, have been identified. However, little is known about the dynamic processes associated with the convergence of rod and cone system signals into ON- and OFF-pathways. Here we show that proper cone vision under mesopic conditions requires rapid adaptational feedback modulation of rod output via hyperpolarization-activated and cyclic nucleotide-gated channels 1. When these channels are absent, sustained rod responses following bright light exposure saturate the retinal network, resulting in a loss of downstream cone signalling. By specific genetic and pharmacological ablation of key signal processing components, regular cone signalling can be restored, thereby identifying the sites involved in functional rod-cone interactions.

  18. Individual variation in cone photoreceptor density in house sparrows: implications for between-individual differences in visual resolution and chromatic contrast.

    Ensminger, Amanda L; Fernández-Juricic, Esteban

    2014-01-01

    Between-individual variation has been documented in a wide variety of taxa, especially for behavioral characteristics; however, intra-population variation in sensory systems has not received similar attention in wild animals. We measured a key trait of the visual system, the density of retinal cone photoreceptors, in a wild population of house sparrows (Passer domesticus). We tested whether individuals differed from each other in cone densities given within-individual variation across the retina and across eyes. We further tested whether the existing variation could lead to individual differences in two aspects of perception: visual resolution and chromatic contrast. We found consistent between-individual variation in the densities of all five types of avian cones, involved in chromatic and achromatic vision. Using perceptual modeling, we found that this degree of variation translated into significant between-individual differences in visual resolution and the chromatic contrast of a plumage signal that has been associated with mate choice and agonistic interactions. However, there was no evidence for a relationship between individual visual resolution and chromatic contrast. The implication is that some birds may have the sensory potential to perform "better" in certain visual tasks, but not necessarily in both resolution and contrast simultaneously. Overall, our findings (a) highlight the need to consider multiple individuals when characterizing sensory traits of a species, and (b) provide some mechanistic basis for between-individual variation in different behaviors (i.e., animal personalities) and for testing the predictions of several widely accepted hypotheses (e.g., honest signaling).

  19. Neural Computations in a Dynamical System with Multiple Time Scales

    Yuanyuan Mi

    2016-09-01

    Full Text Available Neural systems display rich short-term dynamics at various levels, e.g., spike-frequencyadaptation (SFA at single neurons, and short-term facilitation (STF and depression (STDat neuronal synapses. These dynamical features typically covers a broad range of time scalesand exhibit large diversity in different brain regions. It remains unclear what the computationalbenefit for the brain to have such variability in short-term dynamics is. In this study, we proposethat the brain can exploit such dynamical features to implement multiple seemingly contradictorycomputations in a single neural circuit. To demonstrate this idea, we use continuous attractorneural network (CANN as a working model and include STF, SFA and STD with increasing timeconstants in their dynamics. Three computational tasks are considered, which are persistent activity,adaptation, and anticipative tracking. These tasks require conflicting neural mechanisms, andhence cannot be implemented by a single dynamical feature or any combination with similar timeconstants. However, with properly coordinated STF, SFA and STD, we show that the network isable to implement the three computational tasks concurrently. We hope this study will shed lighton the understanding of how the brain orchestrates its rich dynamics at various levels to realizediverse cognitive functions.

  20. Cognitive Impairments in Multiple System Atrophy of the Cerebellar Type

    Hyun J. Hong

    2011-05-01

    Full Text Available Background and Purpose We investigated the cognitive profiles in a large sample of patients with multiple system atrophy-cerebellar ataxia (MSA-C and compared directly them in patients with clinical diagnosis of probable MSA-C without dementia and control subjects with intact cognition. Methods We prospectively enrolled 26 patients with clinical diagnosis of probable MSA-C. All patients underwent a standardized neuropsychological test of the Seoul Neuropsychological Screening Battery. Results The score of Korean version of the Mini- Mental State Examination was significantly lower in patients with MSA-C (27.2 ± 2.5 than in control subjects (28.9 ± 1.0, p = 0.003. Patients with MSA-C showed a significantly worse performance in visuospatial function, 3 words recall, verbal immediate, delayed and recognition memory, visual delayed memory, phonemic and sementic Controlled Oral Word Association Test, and ideomotor praxis (p < 0.05. Conclusions Patients with MSA-C show more severe and more widespread cognitive dysfunctions than controls. Our results also indicate that cognitive dysfunction in patients with MCA-C is suggestive of disruption of the cerebellocortical circuits.

  1. Encryption and validation of multiple signals for optical identification systems

    Perez-Cabre, E [Universitat PoliteGcnica de Catalunya, Department Optica i Optometria, Violinista Vellsola 37, 08222 Terrassa (Spain); Millan, M S [Universitat PoliteGcnica de Catalunya, Department Optica i Optometria, Violinista Vellsola 37, 08222 Terrassa (Spain); Javidi, B [University of Connecticut, Electrical and Computer Engineering Department, 371 Fairfield Road, CT 06269 Storrs (United States)

    2007-07-15

    Multifactor encryption-authentication technique reinforces optical security by allowing the simultaneous A N D-verification of more than one primary image. Instead of basing the identification on a unique signature or piece of information, our goal is to authenticate a given person, object, vehicle by the simultaneous recognition of several factors. Some of them are intrinsic to the person and object or vehicle under control. Other factors, act as keys of the authentication step. Such a system is proposed for situations such as the access control to restricted areas, where the demand of security is high. The multifactor identification method involves double random-phase encoding, fully phase-based encryption and a combined nonlinear joint transform correlator and a classical 4f-correlator for simultaneous recognition and authentication of multiple images. The encoded signal fulfils the general requirements of invisible content, extreme difficulty in counterfeiting and real-time automatic verification. Four reference double-phase encoded images are compared with the retrieved input images obtained in situ from the person or the vehicle whose authentication is wanted and from a database. A recognition step based on the correlation between the signatures and the stored references determines the authentication or rejection of the person and object under surveillance.

  2. Encryption and validation of multiple signals for optical identification systems

    Perez-Cabre, E; Millan, M S; Javidi, B

    2007-01-01

    Multifactor encryption-authentication technique reinforces optical security by allowing the simultaneous A N D-verification of more than one primary image. Instead of basing the identification on a unique signature or piece of information, our goal is to authenticate a given person, object, vehicle by the simultaneous recognition of several factors. Some of them are intrinsic to the person and object or vehicle under control. Other factors, act as keys of the authentication step. Such a system is proposed for situations such as the access control to restricted areas, where the demand of security is high. The multifactor identification method involves double random-phase encoding, fully phase-based encryption and a combined nonlinear joint transform correlator and a classical 4f-correlator for simultaneous recognition and authentication of multiple images. The encoded signal fulfils the general requirements of invisible content, extreme difficulty in counterfeiting and real-time automatic verification. Four reference double-phase encoded images are compared with the retrieved input images obtained in situ from the person or the vehicle whose authentication is wanted and from a database. A recognition step based on the correlation between the signatures and the stored references determines the authentication or rejection of the person and object under surveillance

  3. Neural Computations in a Dynamical System with Multiple Time Scales.

    Mi, Yuanyuan; Lin, Xiaohan; Wu, Si

    2016-01-01

    Neural systems display rich short-term dynamics at various levels, e.g., spike-frequency adaptation (SFA) at the single-neuron level, and short-term facilitation (STF) and depression (STD) at the synapse level. These dynamical features typically cover a broad range of time scales and exhibit large diversity in different brain regions. It remains unclear what is the computational benefit for the brain to have such variability in short-term dynamics. In this study, we propose that the brain can exploit such dynamical features to implement multiple seemingly contradictory computations in a single neural circuit. To demonstrate this idea, we use continuous attractor neural network (CANN) as a working model and include STF, SFA and STD with increasing time constants in its dynamics. Three computational tasks are considered, which are persistent activity, adaptation, and anticipative tracking. These tasks require conflicting neural mechanisms, and hence cannot be implemented by a single dynamical feature or any combination with similar time constants. However, with properly coordinated STF, SFA and STD, we show that the network is able to implement the three computational tasks concurrently. We hope this study will shed light on the understanding of how the brain orchestrates its rich dynamics at various levels to realize diverse cognitive functions.

  4. Therapeutic advances in multiple system atrophy and progressive supranuclear palsy.

    Poewe, Werner; Mahlknecht, Philipp; Krismer, Florian

    2015-09-15

    Multiple system atrophy (MSA) and progressive supranuclear palsy (PSP) are relentlessly progressive neurodegenerative diseases leading to severe disability and ultimately death within less than 10 y. Despite increasing efforts in basic and clinical research, effective therapies for these atypical parkinsonian disorders are lacking. Although earlier small clinical studies in MSA and PSP mainly focused on symptomatic treatment, advances in the understanding of the molecular underpinnings of these diseases and in the search for biomarkers have paved the way for the first large and well-designed clinical trials aiming at disease modification. Targets of intervention in these trials have included α-synuclein inclusion pathology in the case of MSA and tau-related mechanisms in PSP. Since 2013, four large randomized, placebo-controlled, double-blind disease-modification trials have been completed and published, using rasagiline (MSA), rifampicin (MSA), tideglusib (PSP), or davunetide (PSP). All of these failed to demonstrate signal efficacy with regard to the primary outcome measures. In addition, two randomized, placebo-controlled, double-blind trials have studied the efficacy of droxidopa in the symptomatic treatment of neurogenic orthostatic hypotension, including patients with MSA, with positive results in one trial. This review summarizes the design and the outcomes of these and other smaller trials published since 2013 and attempts to highlight priority areas of future therapeutic research in MSA and PSP. © 2015 International Parkinson and Movement Disorder Society. © 2015 International Parkinson and Movement Disorder Society.

  5. Dynamic response of multiple nanobeam system under a moving nanoparticle

    Shahrokh Hosseini Hashemi

    2018-03-01

    Full Text Available In this article, nonlocal continuum based model of multiple nanobeam system (MNBS under a moving nanoparticle is investigated using Eringen’s nonlocal theory. Beam layers are assumed to be coupled by winkler elastic medium and the nonlocal Euler-Bernoulli beam theory is used to model each layer of beam. The Hamilton’s principle, Eigen function technique and the Laplace transform method are employed to solve the governing equations. Analytical solutions of the transverse displacements for MNBs with simply supported boundary condition are presented for double layered and three layered MNBSs. For higher number of layers, the governing set of equations is solved numerically and the results are presented. This study shows that small-scale parameter has a significant effect on dynamic response of MNBS under a moving nanoparticle. Sensitivity of dynamical deflection to variation of nonlocal parameter, stiffness of Winkler elastic medium and number of nanobeams are presented in nondimensional form for each layer. Keywords: Dynamic response, Analytical solution, Moving particle, Nanobeam, Multi-layered nanobeam

  6. Post-operative swallowing in multiple system atrophy.

    Ueha, R; Nito, T; Sakamoto, T; Yamauchi, A; Tsunoda, K; Yamasoba, T

    2016-02-01

    Some patients with multiple system atrophy (MSA) require surgical interventions such as tracheostomy and aspiration prevention. Few studies have investigated the postoperative clinical course of MSA patients. The aim of this study was to determine a management strategy for dysphagia and respiratory disorder in MSA. From 2001 to 2014, 18 MSA patients (13 males and 5 females, 52-76 years) underwent tracheostomy (TR, n = 11) or laryngeal closure (LC, n = 12). Five patients underwent LC following TR. Vocal fold impairment, the degree of dysphagia and pre/post-operative oral ingestion, and postoperative survival time were evaluated retrospectively. Swallowing function was assessed using the penetration aspiration scale (PAS). TR was performed due to respiratory disorder in seven patients and due to dysphagia in four patients. PAS scores ranged 1-8 in TR patients and 7-8 in LC patients. Seven of 11 patients who underwent TR displayed worsened PAS scores, and no patients displayed improved PAS scores following TR. All patients who underwent LC regained complete or partial oral intake after surgery. There were no significant differences in postoperative survival time between the two groups. Considering the impacts of TR and LC on survival time, postoperative feeding and swallowing, LC is a good option for treating MSA patients with dysphagia. © 2015 EAN.

  7. Observations of multiple order parameters in 5f electron systems

    Blackburn, E.

    2005-12-01

    In this thesis, multiple order parameters originating in the same electronic system are studied. The multi-k magnetic structures, where more than one propagation wavevector, k, is observed in the same volume, are considered as prototypical models. The effect of this structure on the elastic and inelastic response is studied. In cubic 3-k uranium rock-salts, unexpected elastic diffraction events were observed at positions in reciprocal space where the structure factor should have been zero. These diffraction peaks are identified with correlations between the (orthogonal) magnetic order parameters. The 3-k structure also affects the observed dynamics; the spin-wave fluctuations in uranium dioxide as observed by inelastic neutron polarization analysis can only be explained on the basis of a 3-k structure. In the antiferromagnetic superconductor UPd 2 Al 3 the magnetic order and the super-conducting state coexist, and are apparently generated by the same heavy fermions. The effect of an external magnetic field on both the normal and superconducting states is examined. In the normal state, the compound displays Fermi-liquid-like behaviour. The inelastic neutron response is strongly renormalized on entering the superconducting state, and high-precision measurements of the low-energy transfer part of this response confirm that the superconducting energy gap has the same symmetry as the antiferromagnetic lattice. (author)

  8. MRI study of degenerative process in multiple system atrophy

    Yagishita, Toshiyuki; Kojima, Shigeyuki; Hirayama, Keizo

    1995-01-01

    The characteristic morphological changes of the brainstem and cerebellar regions of multiple system atrophy (MSA) were studied by MRI in varing subtypes, that is olivoponto cerebellar atrophy (OPCA: 23 cases), striatonigral degeneration (SND: 7 cases) and Shy-Drager's syndrome (SDS: 9 cases). OPCA was characterized by atrophy of the entire regions of the brainstem and the cerebellum. SND and SDS tended to show atrophy similar in type but lessin extent to OPCA. The common lesions in MSA were atrophy of the pontine base and cerebellum, and dilation of the fourth ventricle. Atrophy of the pontine base was more dominant in the inferior part than in the superior part, and cerebellar atrophy was more dominant in the superior part than in the inferior part, indicating that degeneration of the pontocerebellar pathway proceeds principally along fibers connecting the inferior part of the pons and the superior part of the cerebellum. Dilation of the fourth ventricle indicated atrophy of the middle cerebellar peduncle. In almost all the cases of OPCA and about a half the cases of SND and SDS, the pontine base and the middle cerebellar peduncle appeared as high signal intensity on T 2 weighted image and as low intensity on T 1 , suggesting degeneration and demyelination. In a few cases of OPCA, the dorsolateral part of the putamen were demonstrated as low signal intensity on T 2 weighted image. (author)

  9. MRI study of degenerative process in multiple system atrophy

    Yagishita, Toshiyuki; Kojima, Shigeyuki; Hirayama, Keizo [Chiba Univ. (Japan). School of Medicine

    1995-02-01

    The characteristic morphological changes of the brainstem and cerebellar regions of multiple system atrophy (MSA) were studied by MRI in varing subtypes, that is olivoponto cerebellar atrophy (OPCA: 23 cases), striatonigral degeneration (SND: 7 cases) and Shy-Drager`s syndrome (SDS: 9 cases). OPCA was characterized by atrophy of the entire regions of the brainstem and the cerebellum. SND and SDS tended to show atrophy similar in type but lessin extent to OPCA. The common lesions in MSA were atrophy of the pontine base and cerebellum, and dilation of the fourth ventricle. Atrophy of the pontine base was more dominant in the inferior part than in the superior part, and cerebellar atrophy was more dominant in the superior part than in the inferior part, indicating that degeneration of the pontocerebellar pathway proceeds principally along fibers connecting the inferior part of the pons and the superior part of the cerebellum. Dilation of the fourth ventricle indicated atrophy of the middle cerebellar peduncle. In almost all the cases of OPCA and about a half the cases of SND and SDS, the pontine base and the middle cerebellar peduncle appeared as high signal intensity on T{sub 2} weighted image and as low intensity on T{sub 1}, suggesting degeneration and demyelination. In a few cases of OPCA, the dorsolateral part of the putamen were demonstrated as low signal intensity on T{sub 2} weighted image. (author).

  10. Multiple brain metastases irradiation with Eleka Axesse stereotactic system

    Filatov, P. V.; Polovnikov, E. S.; Orlov, K. Yu.; Krutko, A. V.; Kirilova, I. A.; Moskalev, A. V.; Filatova, E. V.; Zheravin, A. A.

    2017-09-01

    Brain metastases are one of the factors complicating the treatment of a malignant tumor. Radiation therapy, especially radiosurgery, plays an important role in the modern treatment practice. During 2011-2016, 32 patients (from 29 to 67 years old) with multiple brain metastases underwent the treatment with SRS or SRT in our center. The number of secondary lesions varied from 2 to 11. Eight patients underwent microsurgery resection. Seven patients had recurrence after whole brain radiotherapy. Thirty patient underwent single fraction SRS and two patients with large metastases (bigger than 3 cm) underwent fractionated SRT. The treatment was done with dedicated linear accelerator stereotactic system Elekta Axesse (Elekta AB, Stockholm, Sweden). Different stereotactic fixation devices were used, namely, Leksell G frame, non-invasive HeadFIX frame, and reinforced thermoplastic mask (IMRT perforation). All treatments included a volumetric modulated arc therapy (VMAT) technique and of Inage Guided Radiation Therapy (IGRT) technique. All lesions were treated from a single isocenter, which allowed reducing the treatment time and overall dose to the patient's body. All patients suffered the treatment satisfactorily. No adverse reactions or complications were met in any case during or right after the treatment. Different stereotactic fixation devices and modern treatment techniques allowed creating an optimal, safe and comfortable way for patient treatment. The treatment time was from 15 to 50 minutes. Patient position verification after or during the treatment demonstrated good accuracy for all fixation types and low level of intrafraction motion.

  11. Optimization of multi-response dynamic systems integrating multiple ...

    It also results in better optimization performance than back-propagation neural network-based approach and data mining-based approach reported by the past researchers. Keywords: multiple responses, multiple regression, weighted dynamic signal-to-noise ratio, performance measure modelling, response function ...

  12. Comparison of PSF maxima and minima of multiple annuli coded aperture (MACA) and complementary multiple annuli coded aperture (CMACA) systems

    Ratnam, Challa; Lakshmana Rao, Vadlamudi; Lachaa Goud, Sivagouni

    2006-10-01

    In the present paper, and a series of papers to follow, the Fourier analytical properties of multiple annuli coded aperture (MACA) and complementary multiple annuli coded aperture (CMACA) systems are investigated. First, the transmission function for MACA and CMACA is derived using Fourier methods and, based on the Fresnel-Kirchoff diffraction theory, the formulae for the point spread function are formulated. The PSF maxima and minima are calculated for both the MACA and CMACA systems. The dependence of these properties on the number of zones is studied and reported in this paper.

  13. Comparison of PSF maxima and minima of multiple annuli coded aperture (MACA) and complementary multiple annuli coded aperture (CMACA) systems

    Ratnam, Challa; Rao, Vadlamudi Lakshmana; Goud, Sivagouni Lachaa

    2006-01-01

    In the present paper, and a series of papers to follow, the Fourier analytical properties of multiple annuli coded aperture (MACA) and complementary multiple annuli coded aperture (CMACA) systems are investigated. First, the transmission function for MACA and CMACA is derived using Fourier methods and, based on the Fresnel-Kirchoff diffraction theory, the formulae for the point spread function are formulated. The PSF maxima and minima are calculated for both the MACA and CMACA systems. The dependence of these properties on the number of zones is studied and reported in this paper

  14. Characterization of a managed aquifer recharge system using multiple tracers.

    Moeck, Christian; Radny, Dirk; Popp, Andrea; Brennwald, Matthias; Stoll, Sebastian; Auckenthaler, Adrian; Berg, Michael; Schirmer, Mario

    2017-12-31

    Knowledge about the residence times of artificially infiltrated water into an aquifer and the resulting flow paths is essential to developing groundwater-management schemes. To obtain this knowledge, a variety of tracers can be used to study residence times and gain information about subsurface processes. Although a variety of tracers exists, their interpretation can differ considerably due to subsurface heterogeneity, underlying assumptions, and sampling and analysis limitations. The current study systematically assesses information gained from seven different tracers during a pumping experiment at a site where drinking water is extracted from an aquifer close to contaminated areas and where groundwater is artificially recharged by infiltrating surface water. We demonstrate that the groundwater residence times estimated using dye and heat tracers are comparable when the thermal retardation for the heat tracer is considered. Furthermore, major ions, acesulfame, and stable isotopes (δ 2 H and δ 18 O) show that mixing of infiltrated water and groundwater coming from the regional flow path occurred and a vertical stratification of the flow system exist. Based on the concentration patterns of dissolved gases (He, Ar, Kr, N 2 , and O 2 ) and chlorinated solvents (e.g., tetrachloroethene), three temporal phases are observed in the ratio between infiltrated water and regional groundwater during the pumping experiment. Variability in this ratio is significantly related to changes in the pumping and infiltration rates. During constant pumping rates, more infiltrated water was extracted, which led to a higher dilution of the regional groundwater. An infiltration interruption caused however, the ratio to change and more regional groundwater is extracted, which led to an increase in all concentrations. The obtained results are discussed for each tracer considered and its strengths and limitations are illustrated. Overall, it is demonstrated that aquifer heterogeneity and

  15. Aliskiren targets multiple systems to alleviate cancer cachexia.

    Wang, Chaoyi; Guo, Dunwei; Wang, Qiang; You, Song; Qiao, Zhongpeng; Liu, Yong; Dai, Hang; Tang, Hua

    2016-11-01

    To examine the effects of aliskiren, a small-molecule renin inhibitor, on cancer cachexia and to explore the underlying mechanisms. A cancer cachexia model was established by subcutaneously injecting C26 mouse colon carcinoma cells into isogenic BALB/c mice. Aliskiren was administered intragastrically [10 mg/kg body weight (BW)] on day 5 (as a preventive strategy, AP group) or on day 12 (as a therapeutic strategy, AT group) after C26 injection. Mice that received no C26 injection (healthy controls, HC group) or only C26 injection but not aliskiren (cancer, CA group) were used as controls. BW, tumor growth, whole body functions, and survival were monitored daily in half of the mice in each group, whereas serum, tumors, and gastrocnemius muscles were harvested from the other mice after sacrifice on day 20 for further analysis. Aliskiren significantly alleviated multiple cachexia‑associated symptoms, including BW loss, tumor burden, muscle wasting, muscular dysfunction, and shortened survival. On the molecular level, aliskiren antagonized cachexia‑induced activation of the renin‑angiotensin system (RAS), systematic and muscular inflammation, oxidative stress, and autophagy‑lysosome as well as ubiquitin‑proteasome stimulation. In addition, early administration of aliskiren before cachexia development (AP group) resulted in more robust effects in alleviating cachexia or targeting underlying mechanisms than administration after cachexia development (AT group). Aliskiren exhibited potent anti‑cachexia activities. These activities were achieved through the targeting of at least four mechanisms underlying cachexia development: RAS activation, increase in systematic inflammation, upregulation of oxidative stress, and stimulation of autophagy-lysosome pathway (ALP) and ubiquitin-proteasome pathway (UPP).

  16. Clinical and MRI correlation in multiple system atrophy

    Negoro, Kiyoshi; Morimatsu, Mitsunori (Yamaguchi Univ., Ube (Japan). School of Medicine)

    1994-05-01

    By using magnetic resonance imaging (MRI), we studied 11 patients with multiple system atrophy (MSA): 5 olivo-pontocerebellar atrophy (OPCA), 2 Shy-Drager syndrome (SDS), and 4 striatonigral degeneration (SND). The diagnoses of OPCA, SDS and SND were clinically made. The MR images were performed on 1.5 tesla MRI unit (Siemens Asahi Medical, Magnetom H15), using a T[sub 2]-weighted spin echo (SE) sequence (TR: 2000-3000 ms, TE: 80-90 ms), a T[sub 1]-weighted SE sequence (TR: 550, TE: 15), and a proton density-weighted (PD) SE sequence (TR: 2000-3000, TE: 12-22). In the patients with OPCA, MRI revealed cerebellar and brainstem atrophy and degeneration of pontine transverse fibers more marked than in the patients with SDS and SND. T[sub 2]-weighted images showed low intensity in posterolateral putamina in one OPCA patient and all of SDS and SND patients. PD images demonstrated the abnormal slit-like high signals in posterolateral putamina in three SND. The degree of cerebellar ataxia was not well correlated with cerebellar and brainstem atrophy and degeneration of pontine transverse fibers. There was a positive correlation between the atrophy of cerebellum and brainstem and the duration of cerebellar ataxia. In most of the patients with Parkinsonism, MRI demonstrated abnormal low signals in putamina on T[sub 2]-weighted images. There were positive correlations between the abnormal low signals putamina and the duration and severity of Parkinsonism. Though abnormal low signals in lateral putamina may be seen in normal aging and other disorders on T[sub 2]-weighted images, it is useful to evaluate Parkinsonism in MSA. We believe that the abnormal slit-like high signals in posterolateral putamina in MSA may suggest loss of neurons and gliosis. (author).

  17. Photoreceptor Outer Segment on Internal Limiting Membrane after Macular Hole Surgery: Implications for Pathogenesis.

    Grinton, Michael E; Sandinha, Maria T; Steel, David H W

    2015-01-01

    This report presents a case, which highlights key principles in the pathophysiology of macular holes. It has been hypothesized that anteroposterior (AP) and tangential vitreous traction on the fovea are the primary underlying factors causing macular holes [Nischal and Pearson; in Kanski and Bowling: Clinical Ophthalmology: A Systemic Approach, 2011, pp 629-631]. Spectral domain optical coherence tomography (OCT) has subsequently corroborated this theory in part but shown that AP vitreofoveal traction is the more common scenario [Steel and Lotery: Eye 2013;27:1-21]. This study was conducted as a single case report. A 63-year old female presented to her optician with blurred and distorted vision in her left eye. OCT showed a macular hole with a minimum linear diameter of 370 µm, with persistent broad vitreofoveal attachment on both sides of the hole edges. The patient underwent combined left phacoemulsification and pars plana vitrectomy, internal limiting membrane (ILM) peel and gas injection. The ILM was examined by electron microscopy and showed the presence of a cone outer segment on the retinal side. Post-operative OCT at 11 weeks showed a closed hole with recovery of the foveal contour and good vision. Our case shows the presence of a photoreceptor outer segment on the retinal side of the ILM and reinforces the importance of tangential traction in the development of some macula holes. The case highlights the theory of transmission of inner retinal forces to the photoreceptors via Müller cells and how a full thickness macular hole defect can occur in the absence of AP vitreomacular traction.

  18. Anaesthetic management of a patient with multiple system atrophy

    Magnetic resonance imaging scan of the brain revealed multiple small ischaemic foci ... Induction was done by propofol 130 mg and atracurium 25 mg. The airway was secured ... distinguished clinically by the predominant motor symptom: the.

  19. Generation, purification and transplantation of photoreceptors derived from human induced pluripotent stem cells.

    Deepak A Lamba

    2010-01-01

    Full Text Available Inherited and acquired retinal degenerations are frequent causes of visual impairment and photoreceptor cell replacement therapy may restore visual function to these individuals. To provide a source of new retinal neurons for cell based therapies, we developed methods to derive retinal progenitors from human ES cells.In this report we have used a similar method to direct induced pluripotent stem cells (iPS from human fibroblasts to a retinal progenitor fate, competent to generate photoreceptors. We also found we could purify the photoreceptors derived from the iPS cells using fluorescence activated cell sorting (FACS after labeling photoreceptors with a lentivirus driving GFP from the IRBP cis-regulatory sequences. Moreover, we found that when we transplanted the FACS purified iPSC derived photoreceptors, they were able to integrate into a normal mouse retina and express photoreceptor markers.This report provides evidence that enriched populations of human photoreceptors can be derived from iPS cells.

  20. A new photosensory function for simple photoreceptors, the intrinsically photoresponsive neurons of the sea slug Onchidium

    Tsukasa Gotow

    2009-12-01

    Full Text Available Simple photoreceptors, namely intrinsically light-sensitive neurons without microvilli and/or cilia, have long been known to exist in the central ganglia of crayfish, Aplysia, Onchidium, and Helix. These simple photoreceptors are not only first-order photosensory cells, but also second-order neurons (interneurons, relaying several kinds of sensory synaptic inputs. Another important issue is that the photoresponses of these simple photoreceptors show very slow kinetics and little adaptation. These characteristics suggest that the simple photoreceptors of the Onchidium have a function in non-image-forming vision, different from classical eye photoreceptors used for cording dynamic images of vision. The cited literature provides evidence that the depolarizing and hyperpolarizing photoresponses of simple photoreceptors play a role in the long-lasting potentiation of synaptic transmission of excitatory and inhibitory sensory inputs, and as well as in the potentiation and the suppression of the subsequent behavioral outputs. In short, we suggest that simple photoreceptors operate in the general potentiation of synaptic transmission and subsequent motor output; i.e., they perform a new photosensory function.

  1. Generation of a genetically encoded marker of rod photoreceptor outer segment growth and renewal

    John J. Willoughby

    2011-10-01

    Vertebrate photoreceptors are specialized light sensing neurons. The photoreceptor outer segment is a highly modified cilium where photons of light are transduced into a chemical and electrical signal. The outer segment has the typical cilary axoneme but, in addition, it has a large number of densely packed, stacked, intramembranous discs. The molecular and cellular mechanisms that contribute to vertebrate photoreceptor outer segment morphogenesis are still largely unknown. Unlike typical cilia, the outer segment is continuously regenerated or renewed throughout the life of the animal through the combined process of distal outer segment shedding and proximal outer segment growth. The process of outer segment renewal was discovered over forty years ago, but we still lack an understanding of how photoreceptors renew their outer segments and few, if any, molecular mechanisms that regulate outer segment growth or shedding have been described. Our lack of progress in understanding how photoreceptors renew their outer segments has been hampered by the difficulty in measuring rates of renewal. We have created a new method that uses heat-shock induction of a fluorescent protein that can be used to rapidly measure outer segment growth rates. We describe this method, the stable transgenic line we created, and the growth rates observed in larval and adult rod photoreceptors using this new method. This new method will allow us to begin to define the genetic and molecular mechanisms that regulate rod outer segment renewal, a crucial aspect of photoreceptor function and, possibly, viability.

  2. Intraocular gene transfer of ciliary neurotrophic factor rescues photoreceptor degeneration in RCS rats.

    Huang, Shun-Ping; Lin, Po-Kang; Liu, Jorn-Hon; Khor, Chin-Ni; Lee, Yih-Jing

    2004-01-01

    Ciliary neurotrophic factor (CNTF) is known as an important factor in the regulation of retinal cell growth. We used both recombinant CNTF and an adenovirus carrying the CNTF gene to regulate retinal photoreceptor expression in a retinal degenerative animal, Royal College of Surgeons (RCS) rats. Cells in the outer nuclear layer of the retinae from recombinant-CNTF-treated, adenoviral-CNTF-treated, saline-operated, and contralateral untreated preparations were examined for those exhibiting CNTF photoreceptor protective effects. Cell apoptosis in the outer nuclear layer of the retinae was also detected. It was found that CNTF had a potent effect on delaying the photoreceptor degeneration process in RCS rats. Furthermore, adenovirus CNTF gene transfer was proven to be better at rescuing photoreceptors than that when using recombinant CNTF, since adenoviral CNTF prolonged the photoreceptor protection effect. The function of the photoreceptors was also examined by taking electroretinograms of different animals. Adenoviral-CNTF-treated eyes showed better retinal function than did the contralateral control eyes. This study indicates that adenoviral CNTF effectively rescues degenerating photoreceptors in RCS rats. Copyright 2004 National Science Council, ROC and S. Karger AG, Basel

  3. Preservation of photoreceptors in dystrophic RCS rats following allo- and xenotransplantation of IPE cells.

    Thumann, Gabriele; Salz, Anna Katharina; Walter, Peter; Johnen, Sandra

    2009-03-01

    To examine whether iris pigment epithelial (IPE) cells transplanted into the subretinal space of Royal College of Surgeons (RCS) rats have the ability to rescue photoreceptors. Rat IPE (rIPE) or human IPE (hIPE) cells were transplanted subretinally in 23-day-old RCS rats. Sham injection and transplantation of ARPE-19 cells served as controls. After 12 weeks, eyes were evaluated for photoreceptor survival by morphometric analysis and electron microscopy. Morphometric analysis showed photoreceptor rescue in all transplanted and sham-injected animals (number of photoreceptors/300 microm retina+/-sd: rIPE 41.67 +/- 28; hIPE 29.50 +/- 16; ARPE-19 36.12 +/- 21; sham 16.56 +/- 6) compared to age-matched, control rats (number of photoreceptors/300 microm retina+/-sd: 9.71 +/- 4). Photoreceptor rescue was prominent in IPE cell-transplanted rats and was significantly greater than sham-injected eyes (p = 0.02 for rIPE and p = 0.04 for hIPE). Since IPE cells transplanted into the subretinal space have the ability to rescue photoreceptors from degeneration in the RCS rat without any harmful effects, IPE cells may represent an ideal cell to genetically modify and thus carry essential genetic information for the repair of defects in the subretinal space.

  4. Exploring lipids with nonlinear optical microscopy in multiple biological systems

    Alfonso-Garcia, Alba

    Lipids are crucial biomolecules for the well being of humans. Altered lipid metabolism may give rise to a variety of diseases that affect organs from the cardiovascular to the central nervous system. A deeper understanding of lipid metabolic processes would spur medical research towards developing precise diagnostic tools, treatment methods, and preventive strategies for reducing the impact of lipid diseases. Lipid visualization remains a complex task because of the perturbative effect exerted by traditional biochemical assays and most fluorescence markers. Coherent Raman scattering (CRS) microscopy enables interrogation of biological samples with minimum disturbance, and is particularly well suited for label-free visualization of lipids, providing chemical specificity without compromising on spatial resolution. Hyperspectral imaging yields large datasets that benefit from tailored multivariate analysis. In this thesis, CRS microscopy was combined with Raman spectroscopy and other label-free nonlinear optical techniques to analyze lipid metabolism in multiple biological systems. We used nonlinear Raman techniques to characterize Meibum secretions in the progression of dry eye disease, where the lipid and protein contributions change in ratio and phase segregation. We employed similar tools to examine lipid droplets in mice livers aboard a spaceflight mission, which lose their retinol content contributing to the onset of nonalcoholic fatty-liver disease. We also focused on atherosclerosis, a disease that revolves around lipid-rich plaques in arterial walls. We examined the lipid content of macrophages, whose variable phenotype gives rise to contrasting healing and inflammatory activities. We also proposed new label-free markers, based on lifetime imaging, for macrophage phenotype, and to detect products of lipid oxidation. Cholesterol was also detected in hepatitis C virus infected cells, and in specific strains of age-related macular degeneration diseased cells by

  5. Coping with 'Dark Sides of the Sun' through Photoreceptor Signaling.

    Demarsy, Emilie; Goldschmidt-Clermont, Michel; Ulm, Roman

    2018-03-01

    Plants grow in constantly changing environments, including highly variable light intensities. Sunlight provides the energy that drives photosynthesis and is thus of the utmost importance for plant growth and the generation of oxygen, which the majority of life on Earth depends on. However, exposure to either insufficient or excess levels of light can have detrimental effects and cause light stress. Whereas exposure to insufficient light limits photosynthetic activity, resulting in 'energy starvation', exposure to excess light can damage the photosynthetic apparatus. Furthermore, strong sunlight is associated with high levels of potentially damaging UV-B radiation. Different classes of photoreceptors play important roles in coping with the negative aspects of sunlight, for which specific mechanisms are emerging that are reviewed here. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Blue and ultraviolet-B light photoreceptors in parsley cells

    Ensminger, P.A.; Schaefer, E.

    1992-01-01

    The authors studied UV-B photoreception in parsley cell cultures with physiological experiments involving temperature shifts and examined the possible role of flavin in blue and UV-B light photo-reception. Cells irradiated with UV-B light (0.5-15 min) at 2 o C have the same fluence requirement for chalcone synthase and flavonoid induction as controls irradiated at 25 o C. This is indicative of a purely photochemical reaction. Cells fed with riboflavin and irradiated with 6 h of UV-containing white light synthesize higher levels of chalcone synthase and flavonoid than unfed controls. This effect did not occur with blue light. These results indicate that flavin-sensitization requires excitation of flavin and the UV-B light photoreceptor. (author)

  7. Lrit1, a Retinal Transmembrane Protein, Regulates Selective Synapse Formation in Cone Photoreceptor Cells and Visual Acuity

    Akiko Ueno

    2018-03-01

    Full Text Available Summary: In the vertebrate retina, cone photoreceptors play crucial roles in photopic vision by transmitting light-evoked signals to ON- and/or OFF-bipolar cells. However, the mechanisms underlying selective synapse formation in the cone photoreceptor pathway remain poorly understood. Here, we found that Lrit1, a leucine-rich transmembrane protein, localizes to the photoreceptor synaptic terminal and regulates the synaptic connection between cone photoreceptors and cone ON-bipolar cells. Lrit1-deficient retinas exhibit an aberrant morphology of cone photoreceptor pedicles, as well as an impairment of signal transmission from cone photoreceptors to cone ON-bipolar cells. Furthermore, we demonstrated that Lrit1 interacts with Frmpd2, a photoreceptor scaffold protein, and with mGluR6, an ON-bipolar cell-specific glutamate receptor. Additionally, Lrit1-null mice showed visual acuity impairments in their optokinetic responses. These results suggest that the Frmpd2-Lrit1-mGluR6 axis regulates selective synapse formation in cone photoreceptors and is essential for normal visual function. : Ueno et al. finds that Lrit1 plays an important role in regulating the synaptic connection between cone photoreceptors and cone ON-bipolar cells. The Frmpd2-Lrit1-mGluR6 axis is crucial for selective synapse formation in cone photoreceptors and for development of normal visual function. Keywords: retina, circuit, synapse formation, cone photoreceptor cell, ON-bipolar cell, visual acuity

  8. Visual cycle and its metabolic support in gecko photoreceptors.

    Kolesnikov, A V; Ala-Laurila, P; Shukolyukov, S A; Crouch, R K; Wiggert, B; Estevez, M E; Govardovskii, V I; Cornwall, M C

    2007-02-01

    Photoreceptors of nocturnal geckos are transmuted cones that acquired rod morphological and physiological properties but retained cone-type phototransduction proteins. We have used microspectrophotometry and microfluorometry of solitary isolated green-sensitive photoreceptors of Tokay gecko to study the initial stages of the visual cycle within these cells. These stages are the photolysis of the visual pigment, the reduction of all-trans retinal to all-trans retinol, and the clearance of all-trans retinol from the outer segment (OS) into the interphotoreceptor space. We show that the rates of decay of metaproducts (all-trans retinal release) and retinal-to-retinol reduction are intermediate between those of typical rods and cones. Clearance of retinol from the OS proceeds at a rate that is typical of rods and is greatly accelerated by exposure to interphotoreceptor retinoid-binding protein, IRBP. The rate of retinal release from metaproducts is independent of the position within the OS, while its conversion to retinol is strongly spatially non-uniform, being the fastest at the OS base and slowest at the tip. This spatial gradient of retinol production is abolished by dialysis of saponin-permeabilized OSs with exogenous NADPH or substrates for its production by the hexose monophosphate pathway (NADP+glucose-6-phosphate or 6-phosphogluconate, glucose-6-phosphate alone). Following dialysis by these agents, retinol production is accelerated by several-fold compared to the fastest rates observed in intact cells in standard Ringer solution. We propose that the speed of retinol production is set by the availability of NADPH which in turn depends on ATP supply within the outer segment. We also suggest that principal source of this ATP is from mitochondria located within the ellipsoid region of the inner segment.

  9. Mechanisms underlying stage-1 TRPL channel translocation in Drosophila photoreceptors.

    Minh-Ha Lieu

    Full Text Available TRP channels function as key mediators of sensory transduction and other cellular signaling pathways. In Drosophila, TRP and TRPL are the light-activated channels in photoreceptors. While TRP is statically localized in the signaling compartment of the cell (the rhabdomere, TRPL localization is regulated by light. TRPL channels translocate out of the rhabdomere in two distinct stages, returning to the rhabdomere with dark-incubation. Translocation of TRPL channels regulates their availability, and thereby the gain of the signal. Little, however, is known about the mechanisms underlying this trafficking of TRPL channels.We first examine the involvement of de novo protein synthesis in TRPL translocation. We feed flies cycloheximide, verify inhibition of protein synthesis, and test for TRPL translocation in photoreceptors. We find that protein synthesis is not involved in either stage of TRPL translocation out of the rhabdomere, but that re-localization to the rhabdomere from stage-1, but not stage-2, depends on protein synthesis. We also characterize an ex vivo eye preparation that is amenable to biochemical and genetic manipulation. We use this preparation to examine mechanisms of stage-1 TRPL translocation. We find that stage-1 translocation is: induced with ATP depletion, unaltered with perturbation of the actin cytoskeleton or inhibition of endocytosis, and slowed with increased membrane sterol content.Our results indicate that translocation of TRPL out of the rhabdomere is likely due to protein transport, and not degradation/re-synthesis. Re-localization from each stage to the rhabdomere likely involves different strategies. Since TRPL channels can translocate to stage-1 in the absence of ATP, with no major requirement of the cytoskeleton, we suggest that stage-1 translocation involves simple diffusion through the apical membrane, which may be regulated by release of a light-dependent anchor in the rhabdomere.

  10. Annual elk calf survival in a multiple carnivore system

    Eacker, Daniel R.; Hebblewhite, Mark; Proffitt, Kelly M.; Jimenez, Benjamin S.; Mitchell, Michael S.; Robinson, Hugh S.

    2016-01-01

    The realized effect of multiple carnivores on juvenile ungulate recruitment may depend on the carnivore assemblage as well as compensation from forage and winter weather severity, which may mediate juvenile vulnerability to predation in ungulates. We used a time-to-event approach to test for the effects of risk factors on annual elk (Cervus canadensis) calf survival and to estimate cause-specific mortality rates for 2 elk populations in adjacent study areas in the southern Bitterroot Valley, Montana, USA, during 2011–2014. We captured and radio-tagged 286 elk calves: 226 neonates, and 60 6-month-old calves. Summer survival probability was less variable than winter (P = 0.12) and averaged 0.55 (95% CI = 0.47–0.63), whereas winter survival varied more than summer and significantly across study years (P = 0.003) and averaged 0.73 (95% CI = 0.64–0.81). During summer, elk calf survival increased with biomass of preferred forage biomass, and was slightly lower following winters with high precipitation; exposure to mountain lion (Puma concolor) predation risk was unimportant. In contrast, during winter, we found that exposure to mountain lion predation risk influenced survival, with a weak negative effect of winter precipitation. We found no evidence that forage availability or winter weather severity mediated vulnerability to mountain lion predation risk in summer or winter (e.g., an interaction), indicating that the effect of mountain lion predation was constant regardless of spatial variation in forage or weather. Mountain lions dominated known causes of elk calf mortality in summer and winter, with estimated cause-specific mortality rates of 0.14 (95% CI = 0.09–0.20) and 0.12 (95% CI = 0.07–0.18), respectively. The effect of carnivores on juvenile ungulate recruitment varies across ecological systems depending on relative carnivore densities. Mountain lions may be the most important carnivore for ungulates, especially where grizzly

  11. A Multiple Sensor Machine Vision System for Automatic Hardwood Feature Detection

    D. Earl Kline; Richard W. Conners; Daniel L. Schmoldt; Philip A. Araman; Robert L. Brisbin

    1993-01-01

    A multiple sensor machine vision prototype is being developed to scan full size hardwood lumber at industrial speeds for automatically detecting features such as knots holes, wane, stain, splits, checks, and color. The prototype integrates a multiple sensor imaging system, a materials handling system, a computer system, and application software. The prototype provides...

  12. Application of multiplicative array techniques for multibeam sounder systems

    Chakraborty, B.

    modification in terms of additional computation or hardware for improved array gain. The present work is devoted towards the study of a better beamforming method i.e. a multiplicative array technique with some modification proposEd. by Brown and Rowland...

  13. Functional Optical Coherence Tomography Enables In Vivo Physiological Assessment of Retinal Rod and Cone Photoreceptors

    Zhang, Qiuxiang; Lu, Rongwen; Wang, Benquan; Messinger, Jeffrey D.; Curcio, Christine A.; Yao, Xincheng

    2015-04-01

    Transient intrinsic optical signal (IOS) changes have been observed in retinal photoreceptors, suggesting a unique biomarker for eye disease detection. However, clinical deployment of IOS imaging is challenging due to unclear IOS sources and limited signal-to-noise ratios (SNRs). Here, by developing high spatiotemporal resolution optical coherence tomography (OCT) and applying an adaptive algorithm for IOS processing, we were able to record robust IOSs from single-pass measurements. Transient IOSs, which might reflect an early stage of light phototransduction, are consistently observed in the photoreceptor outer segment almost immediately (retinal stimulation. Comparative studies of dark- and light-adapted retinas have demonstrated the feasibility of functional OCT mapping of rod and cone photoreceptors, promising a new method for early disease detection and improved treatment of diseases such as age-related macular degeneration (AMD) and other eye diseases that can cause photoreceptor damage.

  14. Coding and decoding for code division multiple user communication systems

    Healy, T. J.

    1985-01-01

    A new algorithm is introduced which decodes code division multiple user communication signals. The algorithm makes use of the distinctive form or pattern of each signal to separate it from the composite signal created by the multiple users. Although the algorithm is presented in terms of frequency-hopped signals, the actual transmitter modulator can use any of the existing digital modulation techniques. The algorithm is applicable to error-free codes or to codes where controlled interference is permitted. It can be used when block synchronization is assumed, and in some cases when it is not. The paper also discusses briefly some of the codes which can be used in connection with the algorithm, and relates the algorithm to past studies which use other approaches to the same problem.

  15. LONGITUDINAL QUANTITATIVE EVALUATION OF PHOTORECEPTOR VOLUME FOLLOWING REPAIR OF MACULA-OFF RETINAL DETACHMENT.

    Narala, Ramsudha; Scarinci, Fabio; Shaarawy, Amr; Simonett, Joseph M; Flaxel, Christina J; Fawzi, Amani A

    2016-08-01

    To quantify photoreceptor volume changes after successful surgical repair of macula-off retinal detachment and to correlate these volumetric changes to postoperative best-corrected visual acuity (BCVA). Retrospective study of 15 eyes of 15 patients with macula-off retinal detachment who underwent successful surgical repair. A minimum of 4 optical coherence tomography scans that straddled the foveal center was used to quantify the central photoreceptor volume (central 1 mm). Mean photoreceptor volume at the first postoperative visit was 0.451 mm, increasing to 0.523 mm at the final postoperative visit (P = 0.004). Mean BCVA improved from 1.13 ± 0.59 logarithm of the minimum angle of resolution units (∼20/270) preoperatively to 0.52 ± 0.42 logarithm of the minimum angle of resolution units (∼20/66) at the final postoperative visit (P = 0.001). Mean photoreceptor volume at either the initial or final visit demonstrated significant correlations with final postoperative BCVA (r = -0.670, P = 0.017 and r = -0.753, P = 0.005, respectively). Shorter time interval from diagnosis to surgery was significantly associated with greater mean final postoperative photoreceptor volume (r = -0.588, P = 0.021) and better mean final postoperative BCVA (r = 0.709, P = 0.003). We observed a significant increase in photoreceptor volume after successful retinal detachment repair; photoreceptor volume was positively associated with BCVA and time to surgery. Our series emphasizes the importance of prompt surgical repair and shows that photoreceptor recovery and volumetric improvement correlate significantly with BCVA.

  16. Three distinct roles for notch in Drosophila R7 photoreceptor specification.

    Andrew Tomlinson

    2011-08-01

    Full Text Available Receptor tyrosine kinases (RTKs and Notch (N proteins are different types of transmembrane receptors that transduce extracellular signals and control cell fate. Here we examine cell fate specification in the Drosophila retina and ask how N acts together with the RTKs Sevenless (Sev and the EGF receptor (DER to specify the R7 photoreceptor. The retina is composed of many hundred ommatidia, each of which grows by recruiting surrounding, undifferentiated cells and directing them to particular fates. The R7 photoreceptor derives from a cohort of three cells that are incorporated together following specification of the R2-R5 and R8 photoreceptors. Two cells of the cohort are specified as the R1/6 photoreceptor type by DER activation. These cells then activate N in the third cell (the R7 precursor. By manipulation of N and RTK signaling in diverse combinations we establish three roles for N in specifying the R7 fate. The first role is to impose a block to photoreceptor differentiation; a block that DER activation cannot overcome. The second role, paradoxically, is to negate the first; Notch activation up-regulates Sev expression, enabling the presumptive R7 cell to receive an RTK signal from R8 that can override the block. The third role is to specify the cell as an R7 rather than an R1/6 once RTK signaling has specified the cells as a photoreceptor. We speculate why N acts both to block and to facilitate photoreceptor differentiation, and provide a model for how N and RTK signaling act combinatorially to specify the R1/6 and R7 photoreceptors as well as the surrounding non-neuronal cone cells.

  17. Excessive Myosin Activity in Mbs Mutants Causes Photoreceptor Movement Out of the Drosophila Eye Disc Epithelium

    Lee, Arnold; Treisman, Jessica E.

    2004-01-01

    Neuronal cells must extend a motile growth cone while maintaining the cell body in its original position. In migrating cells, myosin contraction provides the driving force that pulls the rear of the cell toward the leading edge. We have characterized the function of myosin light chain phosphatase, which down-regulates myosin activity, in Drosophila photoreceptor neurons. Mutations in the gene encoding the myosin binding subunit of this enzyme cause photoreceptors to drop out of the eye disc e...

  18. Presynaptic dystroglycan-pikachurin complex regulates the proper synaptic connection between retinal photoreceptor and bipolar cells.

    Omori, Yoshihiro; Araki, Fumiyuki; Chaya, Taro; Kajimura, Naoko; Irie, Shoichi; Terada, Koji; Muranishi, Yuki; Tsujii, Toshinori; Ueno, Shinji; Koyasu, Toshiyuki; Tamaki, Yasuhiro; Kondo, Mineo; Amano, Shiro; Furukawa, Takahisa

    2012-05-02

    Dystroglycan (DG) is a key component of the dystrophin-glycoprotein complex (DGC) at the neuromuscular junction postsynapse. In the mouse retina, the DGC is localized at the presynapse of photoreceptor cells, however, the function of presynaptic DGC is poorly understood. Here, we developed and analyzed retinal photoreceptor-specific DG conditional knock-out (DG CKO) mice. We found that the DG CKO retina showed a reduced amplitude and a prolonged implicit time of the ERG b-wave. Electron microscopic analysis revealed that bipolar dendrite invagination into the photoreceptor terminus is perturbed in the DG CKO retina. In the DG CKO retina, pikachurin, a DG ligand in the retina, is markedly decreased at photoreceptor synapses. Interestingly, in the Pikachurin(-/-) retina, the DG signal at the ribbon synaptic terminus was severely reduced, suggesting that pikachurin is required for the presynaptic accumulation of DG at the photoreceptor synaptic terminus, and conversely DG is required for pikachurin accumulation. Furthermore, we found that overexpression of pikachurin induces formation and clustering of a DG-pikachurin complex on the cell surface. The Laminin G repeats of pikachurin, which are critical for its oligomerization and interaction with DG, were essential for the clustering of the DG-pikachurin complex as well. These results suggest that oligomerization of pikachurin and its interaction with DG causes DG assembly on the synapse surface of the photoreceptor synaptic terminals. Our results reveal that the presynaptic interaction of pikachurin with DG at photoreceptor terminals is essential for both the formation of proper photoreceptor ribbon synaptic structures and normal retinal electrophysiology.

  19. Association between systemic lupus erythematosus and multiple sclerosis: lupoid sclerosis; Asociacion de LES y esclerosis multiple: esclerosis lupoide.

    Medina, Yimy F; Martinez, Jose B; Fernandez, Andres R; Quintana, Gerardo; Restrepo, Jose Felix; Rondon, Federico; Gamarra, Antonio Iglesias

    2010-07-01

    Multiple sclerosis (MS) and Systemic Lupus Erythematosus (SLE) with/without antiphospholipid syndrome are autoimmune illnesses. It has been described in many occasions the association of these two illnesses and the clinical picture of MS with characteristics of laboratory of SLE. When they affect to the central nervous system they can make it in a defined form for each illness or they can also make it in interposed or combined form of the two illnesses what has been called lupoid sclerosis; making that in some cases difficult the differentiation of the two illnesses and therefore to address the treatment. We present four cases of lupoid sclerosis, discuss the clinical and laboratory characteristics of this entity and we make a differentiation of the multiple sclerosis with the neurological affectation of SLE especially for images and laboratory results.

  20. Complementary shifts in photoreceptor spectral tuning unlock the full adaptive potential of ultraviolet vision in birds.

    Toomey, Matthew B; Lind, Olle; Frederiksen, Rikard; Curley, Robert W; Riedl, Ken M; Wilby, David; Schwartz, Steven J; Witt, Christopher C; Harrison, Earl H; Roberts, Nicholas W; Vorobyev, Misha; McGraw, Kevin J; Cornwall, M Carter; Kelber, Almut; Corbo, Joseph C

    2016-07-12

    Color vision in birds is mediated by four types of cone photoreceptors whose maximal sensitivities (λmax) are evenly spaced across the light spectrum. In the course of avian evolution, the λmax of the most shortwave-sensitive cone, SWS1, has switched between violet (λmax > 400 nm) and ultraviolet (λmax < 380 nm) multiple times. This shift of the SWS1 opsin is accompanied by a corresponding short-wavelength shift in the spectrally adjacent SWS2 cone. Here, we show that SWS2 cone spectral tuning is mediated by modulating the ratio of two apocarotenoids, galloxanthin and 11’,12’-dihydrogalloxanthin, which act as intracellular spectral filters in this cell type. We propose an enzymatic pathway that mediates the differential production of these apocarotenoids in the avian retina, and we use color vision modeling to demonstrate how correlated evolution of spectral tuning is necessary to achieve even sampling of the light spectrum and thereby maintain near-optimal color discrimination.

  1. Seismic isolation systems designed with distinct multiple frequencies

    Wu, Ting-shu; Seidensticker, R.W.

    1991-01-01

    Two systems for seismic base isolation are presented. The main feature of these system is that, instead of only one isolation frequency as in conventional isolation systems, they are designed to have two distinct isolation frequencies. When the responses during an earthquake exceed the design value(s), the system will automatically and passively shift to the secondly isolation frequency. Responses of these two systems to different ground motions including a harmonic motion with frequency same as the primary isolation frequency, show that no excessive amplification will occur. Adoption of these new systems certainly will greatly enhance the safety and reliability of an isolated superstructure against future strong earthquakes. 3 refs

  2. Bipolar Cell-Photoreceptor Connectivity in the Zebrafish (Danio rerio) Retina

    Li, Yong N.; Tsujimura, Taro; Kawamura, Shoji; Dowling, John E.

    2013-01-01

    Bipolar cells convey luminance, spatial and color information from photoreceptors to amacrine and ganglion cells. We studied the photoreceptor connectivity of 321 bipolar cells in the adult zebrafish retina. 1,1'-Dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) was inserted into whole-mounted transgenic zebrafish retinas to label bipolar cells. The photoreceptors that connect to these DiI-labeled cells were identified by transgenic fluorescence or their positions relative to the fluorescent cones, as cones are arranged in a highly-ordered mosaic: rows of alternating blue- (B) and ultraviolet-sensitive (UV) single cones alternate with rows of red- (R) and green-sensitive (G) double cones. Rod terminals intersperse among cone terminals. As many as 18 connectivity subtypes were observed, 9 of which – G, GBUV, RG, RGB, RGBUV, RGRod, RGBRod, RGBUVRod and RRod bipolar cells – accounted for 96% of the population. Based on their axon terminal stratification, these bipolar cells could be further sub-divided into ON, OFF, and ON-OFF cells. The dendritic spread size, soma depth and size, and photoreceptor connections of the 308 bipolar cells within the 9 common connectivity subtypes were determined, and their dendritic tree morphologies and axonal stratification patterns compared. We found that bipolar cells with the same axonal stratification patterns could have heterogeneous photoreceptor connectivity whereas bipolar cells with the same dendritic tree morphology usually had the same photoreceptor connectivity, although their axons might stratify on different levels. PMID:22907678

  3. Photobiomodulation reduces photoreceptor death and regulates cytoprotection in early states of P23H retinal dystrophy

    Kirk, Diana K.; Gopalakrishnan, Sandeep; Schmitt, Heather; Abroe, Betsy; Stoehr, Michele; Dubis, Adam; Carroll, Joseph; Stone, Jonathan; Valter, Krisztina; Eells, Janis

    2013-03-01

    Irradiation by light in the far-red to near-infrared (NIR) region of the spectrum (photobiomodulation, PBM) has been demonstrated to attenuate the severity of neurodegenerative disease in experimental and clinical studies. The purpose of this study was to test the hypothesis that 670 nm PBM would protect against the loss of retinal function and improve photoreceptor survival in a rodent model of retinitis pigmentosa, the P23H transgenic rat. P23H rat pups were treated once per day with a 670 nm LED array (180 sec treatments at 50 mW/cm2; fluence 9 joules/cm2) (Quantum Devices Inc., Barneveld WI) from postnatal day (p) 16-20 or from p10-20. Sham-treated rats were restrained, but not exposed to NIR light. The status of the retina was determined at p22 by assessment of mitochondrial function, oxidative stress and cell death. In a second series of studies, retinal status was assessed at p30 by measuring photoreceptor function by ERG and retinal morphology by Spectral Domain Optical Coherence Tomography (SD-OCT). 670 nm PBM increased retinal mitochondrial cytochrome oxidase activity and upregulated the retina's production of the key mitochondrial antioxidant enzyme, MnSOD. PBM also attenuated photoreceptor cell loss and improved photoreceptor function. PBM protects photoreceptors in the developing P23H retina, by augmenting mitochondrial function and stimulating antioxidant protective pathways. Photobiomodulation may have therapeutic potential, where mitochondrial damage is a step in the death of photoreceptors.

  4. Efficient photoreceptor-targeted gene expression in vivo by recombinant adeno-associated virus.

    Flannery, J G; Zolotukhin, S; Vaquero, M I; LaVail, M M; Muzyczka, N; Hauswirth, W W

    1997-06-24

    We describe a general approach for achieving efficient and cell type-specific expression of exogenous genes in photoreceptor cells of the mammalian retina. Recombinant adeno-associated virus (rAAV) vectors were used to transfer the bacterial lacZ gene or a synthetic green fluorescent protein gene (gfp) to mouse or rat retinas after injection into the subretinal space. Using a proximal murine rod opsin promoter (+86 to -385) to drive expression, reporter gene product was found exclusively in photoreceptors, not in any other retinal cell type or in the adjacent retinal pigment epithelium. GFP-expressing photoreceptors typically encompassed 10-20% of the total retinal area after a single 2-microl injection. Photoreceptors were transduced with nearly 100% efficiency in the region directly surrounding the injection site. We estimate approximately 2.5 million photoreceptors were transduced as a result of the single subretinal inoculation. This level of gene transfer and expression suggests the feasibility of genetic therapy for retinal disease. The gfp-containing rAAV stock was substantially free of both adenovirus and wild-type AAV, as judged by plaque assay and infectious center assay, respectively. Thus, highly purified, helper virus-free rAAV vectors can achieve high-frequency tissue-specific transduction of terminally differentiated, postmitotic photoreceptor cells.

  5. Youngest Brown Dwarf Yet in a Multiple Stellar System

    2000-07-01

    ... and the Sharpest Optical Image (0.18 arcsec) from the VLT so far...! Astronomers are eager to better understand the formation of stars and planets - with an eye on the complex processes that lead to the emergence of our own solar system some 4600 million years ago. Brown Dwarfs (BDs) play a special role in this context. Within the cosmic zoo, they represent a class of "intermediate" objects. While they are smaller than normal stars, they shine by their own energy for a limited time, in contrast to planets. Recent observations with the ESO Very Large Telescope (VLT) of a "young" Brown Dwarf in a multiple stellar system are taking on a particular importance in this connection. An evaluation of the new data by an international team of astronomers [1] shows that it is by far the youngest of only four such objects found in a stellar system so far. The results are now providing new insights into the stellar formation process. This small object is known as TWA-5 B and with a mass of only 15 - 40 times that of Jupiter, it is near the borderline between planets and Brown Dwarfs, cf. the explanatory Appendix to this Press Release. However, visible and infrared VLT spectra unambiguously classify it in the latter category. Accurate positional measurements with the Hubble Space Telescope (HST) and the VLT hint that it is orbiting the central, much heavier and brighter star in this system, TWA-5 A (itself a close double star of which each component presumably has a mass of 0.75 solar masses), with a period that may be as long as 900 years. And, by the way, an (I-band) image of the TWA-5 system is the sharpest delivered by the VLT so far, with an image size of only 0.18 arcsec [2]! Brown Dwarfs: a cool subject In current astronomical terminology, Brown Dwarfs (BDs) are objects whose masses are below those of normal stars - the borderline is believed to be about 8% of the mass of our Sun - but larger than those of planets, cf. [3]. Unlike normal stars, Brown Dwarfs are unable

  6. Multiple System Atrophy with Orthostatic Hypotension (Shy-Drager Syndrome)

    ... the onset of symptoms. A problem with the respiratory system is the most common cause of death. x ... the onset of symptoms. A problem with the respiratory system is the most common cause of death. View ...

  7. Preliminary study on radiation crosslinking of PE-NBR multiple phase system

    Wang Hong; Zhang Wanxi; Sun Jiazhen

    1989-01-01

    The effect of radiation crosslinking on the structure and properties of PE-NBR (polyethylene-acrylonitrile-butadiene rubber) multiple phase system was studied in this paper. The relationship of sol fraction and irradiated dose to multiplephase system was demonstrated

  8. Alternative approaches to reliability modeling of a multiple engineered barrier system

    Ananda, M.M.A.; Singh, A.K.

    1994-01-01

    The lifetime of the engineered barrier system used for containment of high-level radioactive waste will significantly impact the total performance of a geological repository facility. Currently two types of designs are under consideration for an engineered barrier system, single engineered barrier system and multiple engineered barrier system. Multiple engineered barrier system consists of several metal barriers and the waste form (cladding). Some recent work show that a significant improvement of performance can be achieved by utilizing multiple engineered barrier systems. Considering sequential failures for each barrier, we model the reliability of the multiple engineered barrier system. Weibull and exponential lifetime distributions are used through out the analysis. Furthermore, the number of failed engineered barrier systems in a repository at a given time is modeled using a poisson approximation

  9. Multiple Systems in Decision Making: A Neurocomputational Perspective

    Frank, M.J.; Cohen, M.X.; Sanfey, A.G.

    2009-01-01

    Various psychological models posit the existence of two systems that contribute to decision making. The first system is bottom-up, automatic, intuitive, emotional, and implicit, while the second system is top-down, controlled, deliberative, and explicit. It has become increasingly evident that this

  10. Essays on Systemic Risk : An analysis from multiple perspectives

    S. Muns (Sander)

    2016-01-01

    markdownabstractThis thesis is about systemic risk in the financial sector. It considers several aspects of systemic risk. It is a building block for an analysis of the impact of systemic risk on the real economy. It appears that stocks in the financial industry show a strong interdependence

  11. Sequencing dynamic storage systems with multiple lifts and shuttles

    Carlo, Hector J.; Vis, Iris F. A.

    2012-01-01

    New types of Automated Storage and Retrieval Systems (AS/RS) able to achieve high throughput are continuously being developed and require new control polices to take full advantage of the developed system. In this paper, a dynamic storage system has been studied as developed by Vanderlande

  12. Multiple Antennas Systems and Full Duplex Relay Systems with Hardware Impairments: New Performance Limits

    Javed, Sidrah

    2016-12-01

    Next generation of wireless communication mostly relies on multiple-input multipleoutput (MIMO) configuration and full-duplex relaying to improve data-rates, spectrale efficiency, spatial-multiplexing, quality-of-service and energy-efficiency etc. However, multiple radio frequency (RF) transceivers in MIMO system and multi-hops in relay networks, accumulate transceiver impairments, rendering an unacceptable system performance. Majority of the technical contributions either assume ideal hardware or inappropriately model hardware impairments which often induce misleading results especially for high data-rate communication systems. We propose statistical mathematical modeling of various hardware impairment (HWI) to characterize their deteriorating effects on the information signal. In addition, we model the aggregate HWI as improper Gaussian signaling (IGS), to fully characterize their asymmetric properties and the self-interfering signal attribute under I/Q imbalance. The proposed model encourages to adopt asymmetric transmission scheme, as opposed to traditional symmetric signaling. First, we present statistical baseband equivalent mathematical models for general MIMO system and two special scenarios of receive and transmit diversity systems under HWI. Then, we express their achievable rate under PGS and IGS transmit schemes. Moreover, we tune the IGS statistical characteristics to maximize the achievable rate. We also present optimal beam-forming/pre-coding and receive combiner vector for multiple-input single-output (MISO) and single-input multiple output (SIMO) systems, which lead to SDNR maximization. Moreover, we propose an adaptive scheme to switch between maximal IGS (MIGS) and PGS transmission based on the described conditions to reduce computational overhead. Subsequently, two case studies are presented. 1) Outage analysis has been carried out for SIMO, under transceiver distortion noise, for two diversity combining schemes 2) The benefits of employing IGS

  13. Multiple-vent programme to test the pressure suppression system

    Aust, E.; Schwan, H.; Vollbrandt, I.

    1979-01-01

    Three pre-tests with a multiple vent configuration have been performed at the GKSS pressure suppression test facility. First test results indicate significant chugging events with occur periodically with 0.4 to 0.2 Hz. These events appear simultaneously in less than 10 ms at the exit of the three vent pipes and cause pressure pulses in the range of 3 bar. This report gives a short description of the test facility and presents the boundary conditions of the test facility and presents the boundary conditions of the three pre-tests, test results and a first valuation of the experimental informations. (orig.) [de

  14. Responses of an isolation system with distinct multiple frequencies

    Wu, Ting-shu; Seidensticker, R.W.

    1991-01-01

    Base isolation systems are generally designed with a single natural frequency. A major concern for these isolation systems is that, if the dominant frequency of a future earthquake is equal or close to the system's natural frequency, the ground motion will be greatly amplified because of resonance,and the superstructure would suffer severe damages. This paper present an isolation system designed with two distinct frequencies. Its responses to different ground motions, including a harmonic motion, show that no excessive amplification will occur. Adoption of this isolation system would greatly enhance the safety of an isolated superstructure against future strong earthquakes. 3 refs., 4 figs., 2 tabs

  15. Integrated reconfigurable multiple-input–multiple-output antenna system with an ultra-wideband sensing antenna for cognitive radio platforms

    Hussain, Rifaqat

    2015-06-18

    © The Institution of Engineering and Technology 2015. A compact, novel multi-mode, multi-band frequency reconfigurable multiple-input-multiple-output (MIMO) antenna system, integrated with ultra-wideband (UWB) sensing antenna, is presented. The developed model can be used as a complete antenna platform for cognitive radio applications. The antenna system is developed on a single substrate area of dimensions 65 × 120 mm2. The proposed sensing antenna is used to cover a wide range of frequency bands from 710 to 3600 MHz. The frequency reconfigurable dual-element MIMO antenna is integrated with P-type, intrinsic, N-type (PIN) diodes for frequency agility. Different modes of selection are used for the MIMO antenna system reconfigurability to support different wireless system standards. The proposed MIMO antenna configuration is used to cover various frequency bands from 755 to 3450 MHz. The complete system comprising the multi-band reconfigurable MIMO antennas and UWB sensing antenna for cognitive radio applications is proposed with a compact form factor.

  16. A FIRST COMPARISON OF KEPLER PLANET CANDIDATES IN SINGLE AND MULTIPLE SYSTEMS

    Latham, David W.; Quinn, Samuel N.; Carter, Joshua A.; Holman, Matthew J.; Rowe, Jason F.; Borucki, William J.; Bryson, Stephen T.; Howell, Steve B.; Batalha, Natalie M.; Brown, Timothy M.; Buchhave, Lars A.; Caldwell, Douglas A.; Christiansen, Jessie L.; Ciardi, David R.; Cochran, William D.; Dunham, Edward W.; Fabrycky, Daniel C.; Ford, Eric B.; Gautier, Thomas N. III; Gilliland, Ronald L.

    2011-01-01

    In this Letter, we present an overview of the rich population of systems with multiple candidate transiting planets found in the first four months of Kepler data. The census of multiples includes 115 targets that show two candidate planets, 45 with three, eight with four, and one each with five and six, for a total of 170 systems with 408 candidates. When compared to the 827 systems with only one candidate, the multiples account for 17% of the total number of systems, and one-third of all the planet candidates. We compare the characteristics of candidates found in multiples with those found in singles. False positives due to eclipsing binaries are much less common for the multiples, as expected. Singles and multiples are both dominated by planets smaller than Neptune; 69 +2 -3 % for singles and 86 +2 -5 % for multiples. This result, that systems with multiple transiting planets are less likely to include a transiting giant planet, suggests that close-in giant planets tend to disrupt the orbital inclinations of small planets in flat systems, or maybe even prevent the formation of such systems in the first place.

  17. PC-based Multiple Information System Interface (PC/MISI) detailed design and implementation plan

    Dominick, Wayne D. (Editor); Hall, Philip P.

    1985-01-01

    The design plan for the personal computer multiple information system interface (PC/MISI) project is discussed. The document is intended to be used as a blueprint for the implementation of the system. Each component is described in the detail necessary to allow programmers to implement the system. A description of the system data flow and system file structures is given.

  18. Multiple Description Coding for Closed Loop Systems over Erasure Channels

    Østergaard, Jan; Quevedo, Daniel

    2013-01-01

    In this paper, we consider robust source coding in closed-loop systems. In particular, we consider a (possibly) unstable LTI system, which is to be stabilized via a network. The network has random delays and erasures on the data-rate limited (digital) forward channel between the encoder (controller......) and the decoder (plant). The feedback channel from the decoder to the encoder is assumed noiseless. Since the forward channel is digital, we need to employ quantization.We combine two techniques to enhance the reliability of the system. First, in order to guarantee that the system remains stable during packet...... by showing that the system can be cast as a Markov jump linear system....

  19. Everywhere divergent Fourier series with respect to the Walsh system and with respect to multiplicative systems

    Bochkarev, S V

    2004-01-01

    In this paper a new construction of everywhere divergent Fourier-Walsh series is presented. This construction enables one to halve the gap in the Lebesgue-Orlicz classes between the Schipp-Moon lower bound established by using Kolmogorov's construction and the Sjoelin upper bound obtained by using Carleson's method. Fourier series which are everywhere divergent after a rearrangement are constructed with respect to the Walsh system (and to more general systems of characters) with the best lower bound for the Weyl factor. Some results related to an upper bound of the majorant for partial sums of series with respect to rearranged multiplicative systems are established. The results thus obtained show certain merits of harmonic analysis on the dyadic group in clarifying and overcoming fundamental difficulties in the solution of the main problems of Fourier analysis

  20. Existence and multiplicity results for homoclinic orbits of Hamiltonian systems

    Chao-Nien Chen

    1997-03-01

    Full Text Available Homoclinic orbits play an important role in the study of qualitative behavior of dynamical systems. Such kinds of orbits have been studied since the time of Poincare. In this paper, we discuss how to use variational methods to study the existence of homoclinic orbits of Hamiltonian systems.

  1. Ant system for reliability optimization of a series system with multiple-choice and budget constraints

    Nahas, Nabil; Nourelfath, Mustapha

    2005-01-01

    Many researchers have shown that insect colonies behavior can be seen as a natural model of collective problem solving. The analogy between the way ants look for food and combinatorial optimization problems has given rise to a new computational paradigm, which is called ant system. This paper presents an application of ant system in a reliability optimization problem for a series system with multiple-choice constraints incorporated at each subsystem, to maximize the system reliability subject to the system budget. The problem is formulated as a nonlinear binary integer programming problem and characterized as an NP-hard problem. This problem is solved by developing and demonstrating a problem-specific ant system algorithm. In this algorithm, solutions of the reliability optimization problem are repeatedly constructed by considering the trace factor and the desirability factor. A local search is used to improve the quality of the solutions obtained by each ant. A penalty factor is introduced to deal with the budget constraint. Simulations have shown that the proposed ant system is efficient with respect to the quality of solutions and the computing time

  2. Sinusoidal error perturbation reveals multiple coordinate systems for sensorymotor adaptation.

    Hudson, Todd E; Landy, Michael S

    2016-02-01

    A coordinate system is composed of an encoding, defining the dimensions of the space, and an origin. We examine the coordinate encoding used to update motor plans during sensory-motor adaptation to center-out reaches. Adaptation is induced using a novel paradigm in which feedback of reach endpoints is perturbed following a sinewave pattern over trials; the perturbed dimensions of the feedback were the axes of a Cartesian coordinate system in one session and a polar coordinate system in another session. For center-out reaches to randomly chosen target locations, reach errors observed at one target will require different corrections at other targets within Cartesian- and polar-coded systems. The sinewave adaptation technique allowed us to simultaneously adapt both dimensions of each coordinate system (x-y, or reach gain and angle), and identify the contributions of each perturbed dimension by adapting each at a distinct temporal frequency. The efficiency of this technique further allowed us to employ perturbations that were a fraction the size normally used, which avoids confounding automatic adaptive processes with deliberate adjustments made in response to obvious experimental manipulations. Subjects independently corrected errors in each coordinate in both sessions, suggesting that the nervous system encodes both a Cartesian- and polar-coordinate-based internal representation for motor adaptation. The gains and phase lags of the adaptive responses are not readily explained by current theories of sensory-motor adaptation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Default mode network links to visual hallucinations: A comparison between Parkinson's disease and multiple system atrophy.

    Franciotti, Raffaella; Delli Pizzi, Stefano; Perfetti, Bernardo; Tartaro, Armando; Bonanni, Laura; Thomas, Astrid; Weis, Luca; Biundo, Roberta; Antonini, Angelo; Onofrj, Marco

    2015-08-01

    Studying default mode network activity or connectivity in different parkinsonisms, with or without visual hallucinations, could highlight its roles in clinical phenotypes' expression. Multiple system atrophy is the archetype of parkinsonism without visual hallucinations, variably appearing instead in Parkinson's disease (PD). We aimed to evaluate default mode network functions in multiple system atrophy in comparison with PD. Functional magnetic resonance imaging evaluated default mode network activity and connectivity in 15 multiple system atrophy patients, 15 healthy controls, 15 early PD patients matched for disease duration, 30 severe PD patients (15 with and 15 without visual hallucinations), matched with multiple system atrophy for disease severity. Cortical thickness and neuropsychological evaluations were also performed. Multiple system atrophy had reduced default mode network activity compared with controls and PD with hallucinations, and no differences with PD (early or severe) without hallucinations. In PD with visual hallucinations, activity and connectivity was preserved compared with controls and higher than in other groups. In early PD, connectivity was lower than in controls but higher than in multiple system atrophy and severe PD without hallucinations. Cortical thickness was reduced in severe PD, with and without hallucinations, and correlated only with disease duration. Higher anxiety scores were found in patients without hallucinations. Default mode network activity and connectivity was higher in PD with visual hallucinations and reduced in multiple system atrophy and PD without visual hallucinations. Cortical thickness comparisons suggest that functional, rather than structural, changes underlie the activity and connectivity differences. © 2015 International Parkinson and Movement Disorder Society.

  4. Stability analysis of multiple-robot control systems

    Wen, John T.; Kreutz, Kenneth

    1989-01-01

    In a space telerobotic service scenario, cooperative motion and force control of multiple robot arms are of fundamental importance. Three paradigms to study this problem are proposed. They are distinguished by the set of variables used for control design. They are joint torques, arm tip force vectors, and an accelerated generalized coordinate set. Control issues related to each case are discussed. The latter two choices require complete model information, which presents practical modeling, computational, and robustness problems. Therefore, focus is on the joint torque control case to develop relatively model independent motion and internal force control laws. The rigid body assumption allows the motion and force control problems to be independently addressed. By using an energy motivated Lyapunov function, a simple proportional derivative plus gravity compensation type of motion control law is always shown to be stabilizing. The asymptotic convergence of the tracing error to zero requires the use of a generalized coordinate with the contact constraints taken into account. If a non-generalized coordinate is used, only convergence to a steady state manifold can be concluded. For the force control, both feedforward and feedback schemes are analyzed. The feedback control, if proper care has been taken, exhibits better robustness and transient performance.

  5. Nestin Reporter Transgene Labels Multiple Central Nervous System Precursor Cells

    Avery S. Walker

    2010-01-01

    Full Text Available Embryonic neuroepithelia and adult subventricular zone (SVZ stem and progenitor cells express nestin. We characterized a transgenic line that expresses enhanced green fluorescent protein (eGFP specified to neural tissue by the second intronic enhancer of the nestin promoter that had several novel features. During embryogenesis, the dorsal telencephalon contained many and the ventral telencephalon few eGFP+ cells. eGFP+ cells were found in postnatal and adult neurogenic regions. eGFP+ cells in the SVZ expressed multiple phenotype markers, glial fibrillary acidic protein, Dlx, and neuroblast-specific molecules suggesting the transgene is expressed through the lineage. eGFP+ cell numbers increased in the SVZ after cortical injury, suggesting this line will be useful in probing postinjury neurogenesis. In non-neurogenic regions, eGFP was strongly expressed in oligodendrocyte progenitors, but not in astrocytes, even when they were reactive. This eGFP+ mouse will facilitate studies of proliferative neuroepithelia and adult neurogenesis, as well as of parenchymal oligodendrocytes.

  6. Systemic irradiation in multiple myeloma: a report on nineteen cases

    Rostom, A.Y.; O'Cathail, S.M.; Folkes, A.

    1984-01-01

    Nineteen patients with relapsed or resistant multiple myeloma were treated with sequential half-body irradiation (12) and half-body irradiation only (seven). Haematological toxicity was acceptable and recovery was complete in all but two of the 19 patients following half-body irradiation. However, only six of the 12 patients who subsequently had the remaining half irradiated completely recovered. Blood transfusions were required to correct anaemia in six patients, a platelet transfusion was given to one and one patient required both platelet and blood transfusions. No serious haematological complications were observed. Six of the 13 patients who received upper half-body irradiation of probable chest infection, while one patient of the six who received lower half-body irradiation died of this complication. Some of the seven deaths may have been due to radiation pneumonitis. Two patients developed brain secondaries, possibly indicating a change in the natural history of myeloma produced by this new treatment. Subjective improvement was observed in 17 patients and relief of pain usually occurred within the first 24 h. Objective responses were noted in six patients. The median survival for all patients was 6 months with five patients alive 11-28 months at the time of writing. (author)

  7. An architecture model for multiple disease management information systems.

    Chen, Lichin; Yu, Hui-Chu; Li, Hao-Chun; Wang, Yi-Van; Chen, Huang-Jen; Wang, I-Ching; Wang, Chiou-Shiang; Peng, Hui-Yu; Hsu, Yu-Ling; Chen, Chi-Huang; Chuang, Lee-Ming; Lee, Hung-Chang; Chung, Yufang; Lai, Feipei

    2013-04-01

    Disease management is a program which attempts to overcome the fragmentation of healthcare system and improve the quality of care. Many studies have proven the effectiveness of disease management. However, the case managers were spending the majority of time in documentation, coordinating the members of the care team. They need a tool to support them with daily practice and optimizing the inefficient workflow. Several discussions have indicated that information technology plays an important role in the era of disease management. Whereas applications have been developed, it is inefficient to develop information system for each disease management program individually. The aim of this research is to support the work of disease management, reform the inefficient workflow, and propose an architecture model that enhance on the reusability and time saving of information system development. The proposed architecture model had been successfully implemented into two disease management information system, and the result was evaluated through reusability analysis, time consumed analysis, pre- and post-implement workflow analysis, and user questionnaire survey. The reusability of the proposed model was high, less than half of the time was consumed, and the workflow had been improved. The overall user aspect is positive. The supportiveness during daily workflow is high. The system empowers the case managers with better information and leads to better decision making.

  8. Differentiation of retinal ganglion cells and photoreceptor precursors from mouse induced pluripotent stem cells carrying an Atoh7/Math5 lineage reporter.

    Bin-Bin Xie

    Full Text Available The neural retina is a critical component of the visual system, which provides the majority of sensory input in humans. Various retinal degenerative diseases can result in the permanent loss of retinal neurons, especially the light-sensing photoreceptors and the centrally projecting retinal ganglion cells (RGCs. The replenishment of lost RGCs and the repair of optic nerve damage are particularly challenging, as both RGC specification and their subsequent axonal growth and projection involve complex and precise regulation. To explore the developmental potential of pluripotent stem cell-derived neural progenitors, we have established mouse iPS cells that allow cell lineage tracing of progenitors that have expressed Atoh7/Math5, a bHLH transcription factor required for RGC production. These Atoh7 lineage reporter iPS cells encode Cre to replace one copy of the endogenous Atoh7 gene and a Cre-dependent YFP reporter in the ROSA locus. In addition, they express pluripotent markers and are capable of generating teratomas in vivo. Under anterior neural induction and neurogenic conditions in vitro, the Atoh7-Cre/ROSA-YFP iPS cells differentiate into neurons that co-express various RGC markers and YFP, indicating that these neurons are derived from Atoh7-expressing progenitors. Consistent with previous in vivo cell lineage studies, the Atoh7-Cre/ROSA-YFP iPS cells also give rise to a subset of Crx-positive photoreceptor precursors. Furthermore, inhibition of Notch signaling in the iPSC cultures results in a significant increase of YFP-positive RGCs and photoreceptor precursors. Together, these results show that Atoh7-Cre/ROSA-YFP iPS cells can be used to monitor the development and survival of RGCs and photoreceptors from pluripotent stem cells.

  9. Loss of ift122, a Retrograde Intraflagellar Transport (IFT) Complex Component, Leads to Slow, Progressive Photoreceptor Degeneration Due to Inefficient Opsin Transport*

    Boubakri, Meriam; Chaya, Taro; Hirata, Hiromi; Kajimura, Naoko; Kuwahara, Ryusuke; Ueno, Akiko; Malicki, Jarema; Furukawa, Takahisa; Omori, Yoshihiro

    2016-01-01

    In the retina, aberrant opsin transport from cell bodies to outer segments leads to retinal degenerative diseases such as retinitis pigmentosa. Opsin transport is facilitated by the intraflagellar transport (IFT) system that mediates the bidirectional movement of proteins within cilia. In contrast to functions of the anterograde transport executed by IFT complex B (IFT-B), the precise functions of the retrograde transport mediated by IFT complex A (IFT-A) have not been well studied in photoreceptor cilia. Here, we analyzed developing zebrafish larvae carrying a null mutation in ift122 encoding a component of IFT-A. ift122 mutant larvae show unexpectedly mild phenotypes, compared with those of mutants defective in IFT-B. ift122 mutants exhibit a slow onset of progressive photoreceptor degeneration mainly after 7 days post-fertilization. ift122 mutant larvae also develop cystic kidney but not curly body, both of which are typically observed in various ciliary mutants. ift122 mutants display a loss of cilia in the inner ear hair cells and nasal pit epithelia. Loss of ift122 causes disorganization of outer segment discs. Ectopic accumulation of an IFT-B component, ift88, is observed in the ift122 mutant photoreceptor cilia. In addition, pulse-chase experiments using GFP-opsin fusion proteins revealed that ift122 is required for the efficient transport of opsin and the distal elongation of outer segments. These results show that IFT-A is essential for the efficient transport of outer segment proteins, including opsin, and for the survival of retinal photoreceptor cells, rendering the ift122 mutant a unique model for human retinal degenerative diseases. PMID:27681595

  10. Knocking Down Snrnp200 Initiates Demorphogenesis of Rod Photoreceptors in Zebrafish

    Yuan Liu

    2015-01-01

    Full Text Available Purpose. The small nuclear ribonucleoprotein 200 kDa (SNRNP200 gene is a fundamental component for precursor message RNA (pre-mRNA splicing and has been implicated in the etiology of autosomal dominant retinitis pigmentosa (adRP. This study aims to determine the consequences of knocking down Snrnp200 in zebrafish. Methods. Expression of the Snrnp200 transcript in zebrafish was determined via whole mount in situ hybridization. Morpholino oligonucleotide (MO aiming to knock down the expression of Snrnp200 was injected into zebrafish embryos, followed by analyses of aberrant splicing and expression of the U4/U6-U5 tri-small nuclear ribonucleoproteins (snRNPs components and retina-specific transcripts. Systemic changes and retinal phenotypes were further characterized by histological study and immunofluorescence staining. Results. Snrnp200 was ubiquitously expressed in zebrafish. Knocking down Snrnp200 in zebrafish triggered aberrant splicing of the cbln1 gene, upregulation of other U4/U6-U5 tri-snRNP components, and downregulation of a panel of retina-specific transcripts. Systemic defects were found correlated with knockdown of Snrnp200 in zebrafish. Only demorphogenesis of rod photoreceptors was detected in the initial stage, mimicking the disease characteristics of RP. Conclusions. We conclude that knocking down Snrnp200 in zebrafish could alter regular splicing and expression of a panel of genes, which may eventually trigger rod defects.

  11. Photosensory transduction in unicellular eukaryotes: a comparison between related ciliates Blepharisma japonicum and Stentor coeruleus and photoreceptor cells of higher organisms.

    Sobierajska, Katarzyna; Fabczak, Hanna; Fabczak, Stanisław

    2006-06-01

    Blepharisma japonicum and Stentor coeruleus are related ciliates, conspicuous by their photosensitivity. They are capable of avoiding illuminated areas in the surrounding medium, gathering exclusively in most shaded places (photodispersal). Such behaviour results mainly from motile photophobic response occurring in ciliates. This light-avoiding response is observed during a relatively rapid increase in illumination intensity (light stimulus) and consists of cessation of cell movement, a period of backward movement (ciliary reversal), followed by a forward swimming, usually in a new direction. The photosensitivity of ciliates is ascribed to their photoreceptor system, composed of pigment granules, containing the endogenous photoreceptor -- blepharismin in Blepharisma japonicum, and stentorin in Stentor coeruleus. A light stimulus, applied to both ciliates activates specific stimulus transduction processes leading to the electrical changes at the plasma membrane, correlated with a ciliary reversal during photophobic response. These data indicate that both ciliates Blepharisma japonicum and Stentor coeruleus, the lower eukaryotes, are capable of transducing the perceived light stimuli in a manner taking place in some photoreceptor cells of higher eukaryotes. Similarities and differences concerning particular stages of light transduction in eukaryotes at different evolutional levels are discussed in this article.

  12. Multiple classifier systems in texton-based approach for the classification of CT images of Lung

    Gangeh, Mehrdad J.; Sørensen, Lauge; Shaker, Saher B.

    2010-01-01

    In this paper, we propose using texton signatures based on raw pixel representation along with a parallel multiple classifier system for the classification of emphysema in computed tomography images of the lung. The multiple classifier system is composed of support vector machines on the texton.......e., texton size and k value in k-means. Our results show that while aggregation of single decisions by SVMs over various k values using multiple classifier systems helps to improve the results compared to single SVMs, combining over different texton sizes is not beneficial. The performance of the proposed...

  13. Log-Normal Distribution in a Growing System with Weighted and Multiplicatively Interacting Particles

    Fujihara, Akihiro; Tanimoto, Satoshi; Yamamoto, Hiroshi; Ohtsuki, Toshiya

    2018-03-01

    A growing system with weighted and multiplicatively interacting particles is investigated. Each particle has a quantity that changes multiplicatively after a binary interaction, with its growth rate controlled by a weight parameter in a homogeneous symmetric kernel. We consider the system using moment inequalities and analytically derive the log-normal-type tail in the probability distribution function of quantities when the parameter is negative, which is different from the result for single-body multiplicative processes. We also find that the system approaches a winner-take-all state when the parameter is positive.

  14. Application of algorithms and artificial-intelligence approach for locating multiple harmonics in distribution systems

    Hong, Y.-Y.; Chen, Y.-C. [Chung Yuan University (China). Dept. of Electrical Engineering

    1999-05-01

    A new method is proposed for locating multiple harmonic sources in distribution systems. The proposed method first determines the proper locations for metering measurement using fuzzy clustering. Next, an artificial neural network based on the back-propagation approach is used to identify the most likely location for multiple harmonic sources. A set of systematic algorithmic steps is developed until all harmonic locations are identified. The simulation results for an 18-busbar system show that the proposed method is very efficient in locating the multiple harmonics in a distribution system. (author)

  15. Improving Teacher Evaluation Systems: Making the Most of Multiple Measures

    Grissom, Jason A., Ed.; Youngs, Peter, Ed.

    2015-01-01

    This is the first book to gather and address what we have learned about the impacts and challenges of data-intensive teacher evaluation systems--a defining characteristic of the current education policy landscape. Expert researchers and practitioners speak to what we know (and what remains to be known) about evaluation measures themselves, the…

  16. Cognitive Spectrum Efficient Multiple Access Technique using Relay Systems

    Frederiksen, Flemming Bjerge; Prasad, Ramjee

    2007-01-01

    Methods to enhance the use of the frequency spectrum by automatical spectrum sensing plus spectrum sharing in a cognitive radio technology context will be presented and discussed in this paper. Ideas to increase the coverage of cellular systems by relay channels, relay stations and collaborate...

  17. Immunochip Analysis Identifies Multiple Susceptibility Loci for Systemic Sclerosis

    Mayes, Maureen D.; Bossini-Castillo, Lara; Gorlova, Olga; Martin, Jose Ezequiel; Zhou, Xiaodong; Chen, Wei V.; Assassi, Shervin; Ying, Jun; Tan, Filemon K.; Arnett, Frank C.; Reveille, John D.; Guerra, Sandra; Terue, Maria; Carmona, Francisco David; Gregersen, Peter K.; Lee, Annette T.; Lopez-Isac, Elena; Ochoa, Eguzkine; Carreira, Patricia; Simeon, Carmen Pilar; Castellvi, Ivan; Angel Gonzalez-Gay, Miguel; Zhernakova, Alexandra; Padyukov, Leonid; Aarcon-Riquelme, Marta; Wijmenga, Cisca; Beretta, Lorenzo; Riemekasten, Gabriela; Witte, Torsten; Hunzelmann, Nicolas; Kreuter, Alexander; Distler, Jorg H. W.; Voskuy, Alexandre E.; Schuerwegh, Annemie J.; Hesselstrand, Roger; Nordin, Annika; Airo, Paolo; Lunardi, Claudio; Shiels, Paul; van Laar, Jacob M.; Herrick, Ariane; Worthington, Jane; Denton, Christopher; Wigley, Fredrick M.; Hummers, Laura K.; Varga, John; Hinchcliff, Monique E.; Baron, Murray; Hudson, Marie; Pope, Janet E.

    2014-01-01

    In this study, 1,833 systemic sclerosis (SSc) cases and 3,466 controls were genotyped with the Immunochip array. Classical alleles, amino acid residues, and SNPs across the human leukocyte antigen (HLA) region were imputed and tested. These analyses resulted in a model composed of six polymorphic

  18. Multiple solutions for a quasilinear (p,q-elliptic system

    Seyyed Mohsen Khalkhali

    2013-06-01

    Full Text Available In this article we show the existence of three weak solutions of a Dirichlet quasilinear elliptic system of differential equations which involves a general (p,q-elliptic operator in divergence, with $1

  19. Multiple applications of the Boussignac continuous positive airway pressure system

    Dieperink, Willem

    2008-01-01

    Continuous positive airway pressure, (CPAP) is a form of treatment to support patients with dyspnea. For the application of CPAP a mechanical ventilator or complex CPAP apparatus is mostly used. The Boussignac CPAP (BCPAP) system developed by George Boussignac does not need such apparatus. The BCPAP

  20. Multiple Systems of Spatial Memory: Evidence from Described Scenes

    Avraamides, Marios N.; Kelly, Jonathan W.

    2010-01-01

    Recent models in spatial cognition posit that distinct memory systems are responsible for maintaining transient and enduring spatial relations. The authors used perspective-taking performance to assess the presence of these enduring and transient spatial memories for locations encoded through verbal descriptions. Across 3 experiments, spatial…

  1. Solving modified systems with multiple right-hand sides

    Simoncini, V.; Gallopoulos, E. [Univ. of Patras (Greece)

    1996-12-31

    In this talk we discuss the iterative solution of large linear systems of the form (A + USV{sup H})X = B, where A is an n x n non-Hermitian matrix, USV{sup H} is a rank-r modification of A and B is of rank s with s, r {much_lt} n. We analyze several approaches that exploit the structure of the coefficient matrix so as to solve the systems more efficiently than if one were to apply a non-hermitian solver to the original systems. In the development of procedures, we take into account the presence of both the low-rank modification and the several right-hand sides. Interesting issues connected to this problem originate from the quest for techniques that accelerate the underlying iterative solvers: preconditioning (e.g. inner-outer iteration strategies), domain decomposition, and continuation methods. Experiments are provided to analyze the behavior of the methods depending on the structure of the rectangular matrices. Preconditioning strategies are explored for an efficient implementation on the transformed systems.

  2. System identification via sparse multiple kernel-based regularization using sequential convex optimization techniques

    Chen, Tianshi; Andersen, Martin Skovgaard; Ljung, Lennart

    2014-01-01

    Model estimation and structure detection with short data records are two issues that receive increasing interests in System Identification. In this paper, a multiple kernel-based regularization method is proposed to handle those issues. Multiple kernels are conic combinations of fixed kernels...

  3. Building an evolvable prototype for a multiple GAAP accounting information system

    Vanhoof, E.; De Bruyn, P.; Aerts, Walter; Verelst, J.; Aveiro, D.; Pergl, R.; Gouveia, D.

    In this paper we build a prototype of an evolvable Accounting Information System (AIS) that supports multiple Generally Accepted Accounting Standards (GAAP) reporting. Reporting in multiple GAAP can have different origins: differences in local and tax GAAP, belonging to an economic group or

  4. Two Women with Multiple Disabilities Communicate with Distant Partners via a Special Text Messaging System

    Lancioni, Giulio E.; O'Reilly, Mark F.; Singh, Nirbhay N.; Sigafoos, Jeff; Green, Vanessa A.; Oliva, Doretta; Alberti, Gloria; Carrella, Luigina

    2013-01-01

    This study extended the research on a special text messaging system, which allows persons with multiple disabilities to (a) write and send messages to distant partners and (b) have messages from those partners read out to them. The study involved two women with multiple disabilities (including blindness or minimal residual vision). The system…

  5. H-infty Control of systems with multiple i/o delays

    Agoes Ariffin Moelja, A.A.; Meinsma, Gjerrit; Mirkin, Leonid

    2003-01-01

    In this paper the standard (four-block) H-infty control problem for systems with multiple i/o delays in the feedback loop is studied. The central idea is to see the multiple delay operator as a special series connection of elementary delay operators, called the adobe delay operators. The adobe delay

  6. Assessing Photoreceptor Structure in Retinitis Pigmentosa and Usher Syndrome.

    Sun, Lynn W; Johnson, Ryan D; Langlo, Christopher S; Cooper, Robert F; Razeen, Moataz M; Russillo, Madia C; Dubra, Alfredo; Connor, Thomas B; Han, Dennis P; Pennesi, Mark E; Kay, Christine N; Weinberg, David V; Stepien, Kimberly E; Carroll, Joseph

    2016-05-01

    The purpose of this study was to examine cone photoreceptor structure in retinitis pigmentosa (RP) and Usher syndrome using confocal and nonconfocal split-detector adaptive optics scanning light ophthalmoscopy (AOSLO). Nineteen subjects (11 RP, 8 Usher syndrome) underwent ophthalmic and genetic testing, spectral-domain optical coherence tomography (SD-OCT), and AOSLO imaging. Split-detector images obtained in 11 subjects (7 RP, 4 Usher syndrome) were used to assess remnant cone structure in areas of altered cone reflectivity on confocal AOSLO. Despite normal interdigitation zone and ellipsoid zone appearance on OCT, foveal and parafoveal cone densities derived from confocal AOSLO images were significantly lower in Usher syndrome compared with RP. This was due in large part to an increased prevalence of non-waveguiding cones in the Usher syndrome retina. Although significantly correlated to best-corrected visual acuity and foveal sensitivity, cone density can decrease by nearly 38% before visual acuity becomes abnormal. Aberrantly waveguiding cones were noted within the transition zone of all eyes and corresponded to intact inner segment structures. These remnant cones decreased in density and increased in diameter across the transition zone and disappeared with external limiting membrane collapse. Foveal cone density can be decreased in RP and Usher syndrome before visible changes on OCT or a decline in visual function. Thus, AOSLO imaging may allow more sensitive monitoring of disease than current methods. However, confocal AOSLO is limited by dependence on cone waveguiding, whereas split-detector AOSLO offers unambiguous and quantifiable visualization of remnant cone inner segment structure. Confocal and split-detector thus offer complementary insights into retinal pathology.

  7. Friedrichs systems in a Hilbert space framework: Solvability and multiplicity

    Antonić, N.; Erceg, M.; Michelangeli, A.

    2017-12-01

    The Friedrichs (1958) theory of positive symmetric systems of first order partial differential equations encompasses many standard equations of mathematical physics, irrespective of their type. This theory was recast in an abstract Hilbert space setting by Ern, Guermond and Caplain (2007), and by Antonić and Burazin (2010). In this work we make a further step, presenting a purely operator-theoretic description of abstract Friedrichs systems, and proving that any pair of abstract Friedrichs operators admits bijective extensions with a signed boundary map. Moreover, we provide sufficient and necessary conditions for existence of infinitely many such pairs of spaces, and by the universal operator extension theory (Grubb, 1968) we get a complete identification of all such pairs, which we illustrate on two concrete one-dimensional examples.

  8. Collision avoidance for multiple Lagrangian dynamical systems with gyroscopic forces

    Lorenzo Sabattini

    2017-01-01

    Full Text Available This article introduces a novel methodology for dealing with collision avoidance for groups of mobile robots. In particular, full dynamics are considered, since each robot is modeled as a Lagrangian dynamical system moving in a three-dimensional environment. Gyroscopic forces are utilized for defining the collision avoidance control strategy: This kind of forces leads to avoiding collisions, without interfering with the convergence properties of the multi-robot system’s desired control law. Collision avoidance introduces, in fact, a perturbation on the nominal behavior of the system: We define a method for choosing the direction of the gyroscopic force in an optimal manner, in such a way that perturbation is minimized. Collision avoidance and convergence properties are analytically demonstrated, and simulation results are provided for validation purpose.

  9. Comparative analytics of infusion pump data across multiple hospital systems.

    Catlin, Ann Christine; Malloy, William X; Arthur, Karen J; Gaston, Cindy; Young, James; Fernando, Sudheera; Fernando, Ruchith

    2015-02-15

    A Web-based analytics system for conducting inhouse evaluations and cross-facility comparisons of alert data generated by smart infusion pumps is described. The Infusion Pump Informatics (IPI) project, a collaborative effort led by research scientists at Purdue University, was launched in 2009 to provide advanced analytics and tools for workflow analyses to assist hospitals in determining the significance of smart-pump alerts and reducing nuisance alerts. The IPI system allows facility-specific analyses of alert patterns and trends, as well as cross-facility comparisons of alert data uploaded by more than 55 participating institutions using different types of smart pumps. Tools accessible through the IPI portal include (1) charts displaying aggregated or breakout data on the top drugs associated with alerts, numbers of alerts per device or care area, and override-to-alert ratios, (2) investigative reports that can be used to characterize and analyze pump-programming errors in a variety of ways (e.g., by drug, by infusion type, by time of day), and (3) "drill-down" workflow analytics enabling users to evaluate alert patterns—both internally and in relation to patterns at other hospitals—in a quick and efficient stepwise fashion. The formation of the IPI analytics system to support a community of hospitals has been successful in providing sophisticated tools for member facilities to review, investigate, and efficiently analyze smart-pump alert data, not only within a member facility but also across other member facilities, to further enhance smart pump drug library design. Copyright © 2015 by the American Society of Health-System Pharmacists, Inc. All rights reserved.

  10. Absorption in multiple scattering systems of coated spheres: design applications

    Stout, Brian; Andraud, Christine; Stout, Sophie; Lafait, Jacques

    2003-01-01

    We illustrate the utility of some recently derived transfer matrix methods for electromagnetic scattering calculations in systems composed of coated spherical scatterers. Any of the spherical coatings, cores, or host media may be composed of absorbing materials. Our formulae permit the calculation of local absorption in either orientation fixed or orientation averaged situations. We introduce methods for estimating the macroscopic transport properties of such media, and show how our scattering calculations can permit 'design' optimization of macroscopic properties

  11. Multiple-Feature Extracting Modules Based Leak Mining System Design

    Ying-Chiang Cho

    2013-01-01

    mining system that is equipped with SQL injection vulnerability detection, by means of an algorithm developed for the web crawler. In addition, we analyze portal sites of the governments of various countries or regions in order to investigate the information leaking status of each site. Subsequently, we analyze the database structure and content of each site, using the data collected. Thus, we make use of practical verification in order to focus on information security and privacy through black-box testing.

  12. Extent of reaction in open systems with multiple heterogeneous reactions

    Friedly, John C.

    1991-01-01

    The familiar batch concept of extent of reaction is reexamined for systems of reactions occurring in open systems. Because species concentrations change as a result of transport processes as well as reactions in open systems, the extent of reaction has been less useful in practice in these applications. It is shown that by defining the extent of the equivalent batch reaction and a second contribution to the extent of reaction due to the transport processes, it is possible to treat the description of the dynamics of flow through porous media accompanied by many chemical reactions in a uniform, concise manner. This approach tends to isolate the reaction terms among themselves and away from the model partial differential equations, thereby enabling treatment of large problems involving both equilibrium and kinetically controlled reactions. Implications on the number of coupled partial differential equations necessary to be solved and on numerical algorithms for solving such problems are discussed. Examples provided illustrate the theory applied to solute transport in groundwater flow.

  13. Wearable flex sensor system for multiple badminton player grip identification

    Jacob, Alvin; Zakaria, Wan Nurshazwani Wan; Tomari, Mohd Razali Bin Md; Sek, Tee Kian; Suberi, Anis Azwani Muhd

    2017-09-01

    This paper focuses on the development of a wearable sensor system to identify the different types of badminton grip that is used by a player during training. Badminton movements and strokes are fast and dynamic, where most of the involved movement are difficult to identify with the naked eye. Also, the usage of high processing optometric motion capture system is expensive and causes computational burden. Therefore, this paper suggests the development of a sensorized glove using flex sensor to measure a badminton player's finger flexion angle. The proposed Hand Monitoring Module (HMM) is connected to a personal computer through Bluetooth to enable wireless data transmission. The usability and feasibility of the HMM to identify different grip types were examined through a series of experiments, where the system exhibited 70% detection ability for the five different grip type. The outcome plays a major role in training players to use the proper grips for a badminton stroke to achieve a more powerful and accurate stroke execution.

  14. Loss and gain of cone types in vertebrate ciliary photoreceptor evolution.

    Musser, Jacob M; Arendt, Detlev

    2017-11-01

    Ciliary photoreceptors are a diverse cell type family that comprises the rods and cones of the retina and other related cell types such as pineal photoreceptors. Ciliary photoreceptor evolution has been dynamic during vertebrate evolution with numerous gains and losses of opsin and phototransduction genes, and changes in their expression. For example, early mammals lost all but two cone opsins, indicating loss of cone receptor types in response to nocturnal lifestyle. Our review focuses on the comparison of specifying transcription factors and cell type-specific transcriptome data in vertebrate retinae to build and test hypotheses on ciliary photoreceptor evolution. Regarding cones, recent data reveal that a combination of factors specific for long-wavelength sensitive opsin (Lws)- cones in non-mammalian vertebrates (Thrb and Rxrg) is found across all differentiating cone photoreceptors in mice. This suggests that mammalian ancestors lost all but one ancestral cone type, the Lws-cone. We test this hypothesis by a correlation analysis of cone transcriptomes in mouse and chick, and find that, indeed, transcriptomes of all mouse cones are most highly correlated to avian Lws-cones. These findings underscore the importance of specifying transcription factors in tracking cell type evolution, and shed new light on the mechanisms of cell type loss and gain in retina evolution. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  15. In vitro transdifferentiation of human peripheral blood mononuclear cells to photoreceptor-like cells

    Yukari Komuta

    2016-06-01

    Full Text Available Direct reprogramming is a promising, simple and low-cost approach to generate target cells from somatic cells without using induced pluripotent stem cells. Recently, peripheral blood mononuclear cells (PBMCs have attracted considerable attention as a somatic cell source for reprogramming. As a cell source, PBMCs have an advantage over dermal fibroblasts with respect to the ease of collecting tissues. Based on our studies involving generation of photosensitive photoreceptor cells from human iris cells and human dermal fibroblasts by transduction of photoreceptor-related transcription factors via retrovirus vectors, we transduced these transcription factors into PBMCs via Sendai virus vectors. We found that retinal disease-related genes were efficiently detected in CRX-transduced cells, most of which are crucial to photoreceptor functions. In functional studies, a light-induced inward current was detected in some CRX-transduced cells. Moreover, by modification of the culture conditions including additional transduction of RAX1 and NEUROD1, we found a greater variety of retinal disease-related genes than that observed in CRX-transduced PBMCs. These data suggest that CRX acts as a master control gene for reprogramming PBMCs into photoreceptor-like cells and that our induced photoreceptor-like cells might contribute to individualized drug screening and disease modeling of inherited retinal degeneration.

  16. Mef2d is essential for the maturation and integrity of retinal photoreceptor and bipolar cells.

    Omori, Yoshihiro; Kitamura, Tamiki; Yoshida, Satoyo; Kuwahara, Ryusuke; Chaya, Taro; Irie, Shoichi; Furukawa, Takahisa

    2015-05-01

    Mef2 transcription factors play a crucial role in cardiac and skeletal muscle differentiation. We found that Mef2d is highly expressed in the mouse retina and its loss causes photoreceptor degeneration similar to that observed in human retinitis pigmentosa patients. Electroretinograms (ERGs) were severely impaired in Mef2d-/- mice. Immunohistochemistry showed that photoreceptor and bipolar cell synapse protein levels severely decreased in the Mef2d-/- retina. Expression profiling by microarray analysis showed that Mef2d is required for the expression of various genes in photoreceptor and bipolar cells, including cone arrestin, Guca1b, Pde6h and Cacna1s, which encode outer segment and synapse proteins. We also observed that Mef2d synergistically activates the cone arrestin (Arr3) promoter with Crx, suggesting that functional cooperation between Mef2d and Crx is important for photoreceptor cell gene regulation. Taken together, our results show that Mef2d is essential for photoreceptor and bipolar cell gene expression, either independently or cooperatively with Crx. © 2015 Institution for Protein Research. Genes to Cells published by Wiley Publishing Asia Pty Ltd and the Molecular Biology Society of Japan.

  17. Optimal Operation System of the Integrated District Heating System with Multiple Regional Branches

    Kim, Ui Sik; Park, Tae Chang; Kim, Lae-Hyun; Yeo, Yeong Koo

    This paper presents an optimal production and distribution management for structural and operational optimization of the integrated district heating system (DHS) with multiple regional branches. A DHS consists of energy suppliers and consumers, district heating pipelines network and heat storage facilities in the covered region. In the optimal management system, production of heat and electric power, regional heat demand, electric power bidding and sales, transport and storage of heat at each regional DHS are taken into account. The optimal management system is formulated as a mixed integer linear programming (MILP) where the objectives is to minimize the overall cost of the integrated DHS while satisfying the operation constraints of heat units and networks as well as fulfilling heating demands from consumers. Piecewise linear formulation of the production cost function and stairwise formulation of the start-up cost function are used to compute nonlinear cost function approximately. Evaluation of the total overall cost is based on weekly operations at each district heat branches. Numerical simulations show the increase of energy efficiency due to the introduction of the present optimal management system.

  18. Solving problems by interrogating sets of knowledge systems: Toward a theory of multiple knowledge systems

    Dekorvin, Andre

    1989-01-01

    The main purpose is to develop a theory for multiple knowledge systems. A knowledge system could be a sensor or an expert system, but it must specialize in one feature. The problem is that we have an exhaustive list of possible answers to some query (such as what object is it). By collecting different feature values, in principle, it should be possible to give an answer to the query, or at least narrow down the list. Since a sensor, or for that matter an expert system, does not in most cases yield a precise value for the feature, uncertainty must be built into the model. Also, researchers must have a formal mechanism to be able to put the information together. Researchers chose to use the Dempster-Shafer approach to handle the problems mentioned above. Researchers introduce the concept of a state of recognition and point out that there is a relation between receiving updates and defining a set valued Markov Chain. Also, deciding what the value of the next set valued variable is can be phrased in terms of classical decision making theory such as minimizing the maximum regret. Other related problems are examined.

  19. Phase synchronization of multiple klystrons in RF system

    Kwon, S.; Regan, A.; Wang, Y.M.; Rohlev, T.

    1998-01-01

    The Low Energy Demonstration Accelerator (LEDA) being constructed at Los Alamos National Laboratory will serve as the prototype for the low energy section of the Acceleration Production of Tritium (APT) accelerator. The first LEDA RF system includes three, 1.2 MW, 350 MHz, continuous wave, klystrons driving a radio frequency quadrupole (RFQ). A phase control loop is necessary for each individual klystron in order to guarantee the phase matching of these klystrons. To meet this objective, they propose adaptive PI controllers which are based on simple adaptive control. These controllers guarantee not only phase matching but also amplitude matching

  20. Multiple time digitizers and a trigger system for drift chambers

    Eggert, K.; Engster, C.; Koningsveld, L. van; Por, G.; Verweij, H.

    1980-01-01

    The architecture of a readout system is described which will be used in conjunction with the muon detector in the UA-1 experiment at the anti pp collider at CERN. In addition to measuring drift time for spatial information, the system provides a fast trigger (< 1 μs after drift time) and a second level trigger decision based on a fast microprocessor. The fast trigger part allows the use of the muon detector as an active trigger element, while a second level trigger decision using detailed digitizer data is included for adequate reduction of the trigger rate. The multipole time digitizer (MTD) is based on the use of fast RAMs (256 x 4) as 125 MHz shift registers, giving time bins of 8 ns and a time range of 2 μs (256 x 8 ns). The high input rate has imposed a fast readout and transfer to a buffer in the controller. The data in this buffer is reordered according to wire number and corresponding times. Together with look-up tables this allows fast processing of the data for a second level trigger. (orig.)

  1. Multiple Resource Host Architecture (MRHA) for the Mobile Detection Assessment Response System (MDARS) Revision A

    Everett, H

    2000-01-01

    The Mobile Detection Assessment and Response System (MDARS) program employs multiple robotic security platforms operating under the high level control of a remote host, with the direct supervision of a human operator...

  2. Performance Analysis of a Threshold-Based Parallel Multiple Beam Selection Scheme for WDM FSO Systems

    Nam, Sung Sik; Alouini, Mohamed-Slim; Ko, Young-Chai

    2018-01-01

    In this paper, we statistically analyze the performance of a threshold-based parallel multiple beam selection scheme for a free-space optical (FSO) based system with wavelength division multiplexing (WDM) in cases where a pointing error has occurred

  3. System-wide versus component-specific trust using multiple aids.

    Keller, David; Rice, Stephen

    2010-01-01

    Previous research in operator trust toward automated aids has focused primarily on single aids. The current study focuses on how operator trust is affected by the presence of multiple aids. Two competing theories of multiple-trust are presented. A component-specific trust theory predicts that operators will differentially place their trust in automated aids that vary in reliability. A system-wide trust theory predicts that operators will treat multiple imperfect aids as one "system" and merge their trust across aids despite differences in the aids' reliability. A simulated flight task was used to test these theories, whereby operators performed a pursuit tracking task while concurrently monitoring multiple system gauges that were augmented with perfect or imperfect automated aids. The data revealed that a system-wide trust theory best predicted the data; operators merged their trust across both aids, behaving toward a perfectly reliable aid in the same manner as they did towards unreliable aids.

  4. Estimation of Multiple Point Sources for Linear Fractional Order Systems Using Modulating Functions

    Belkhatir, Zehor; Laleg-Kirati, Taous-Meriem

    2017-01-01

    This paper proposes an estimation algorithm for the characterization of multiple point inputs for linear fractional order systems. First, using polynomial modulating functions method and a suitable change of variables the problem of estimating

  5. Responsive Neurostimulation System (RNS in setting of cranioplasty and history of multiple craniotomies

    Jason Ledesma

    2016-09-01

    Conclusion: The case illustrates a possible limitation of SEEG placement, particularly in patients with a history of cranioplasty and multiple prior craniotomies. We also describe the first placement of an RNS generator and system in the setting of prior cranioplasty.

  6. On synthesis and optimization of cooling water systems with multiple cooling towers

    Gololo, KV

    2011-01-01

    Full Text Available -1 On Synthesis and Optimization of Cooling Water Systems with Multiple Cooling Towers Khunedi Vincent Gololo?? and Thokozani Majozi*? ? Department of Chemical Engineering, University of Pretoria, Lynnwood Road, Pretoria, 0002, South Africa ? Modelling...

  7. Distribution of macular xanthophylls between domains in a model of photoreceptor outer segment membranes.

    Wisniewska, Anna; Subczynski, Witold K

    2006-10-15

    A model of photoreceptor outer segment (POS) membranes has been proposed, consisting of an equimolar ternary mixture of 1-palmitoyl-2-docosahexaenoylphosphatidylcholine/distearoylphosphatidylcholine/cholesterol. It was shown that, as in membranes made from the raft-forming mixture, in the model of POS membranes, two domains are formed: the raft domain (detergent resistant membranes, DRM), and the bulk domain (detergent soluble membranes, DSM). Saturation-recovery EPR discrimination by oxygen transport method also demonstrated the presence of two domains in this model system in situ at a wide range of temperatures (10-55 degrees C), showing additionally that neither lutein nor zeaxanthin at 1 mol% affect the formation of these domains. These membrane domains have been separated using cold Triton X-100 extraction from a model of POS membranes containing 1 mol% of either lutein or zeaxanthin. The results indicated that the macular xanthophylls lutein and zeaxanthin are substantially excluded from DRM and remain concentrated in DSM, a domain enriched in highly unsaturated docosahexaenoyl acid which is abundant in retina membranes. The concentration of xanthophylls in DRM and DSM calculated as the mol ratio of either xanthophyll to total lipid (phospholipid+cholesterol) was 0.0028 and 0.0391, respectively. Thus, xanthophylls are about 14 times more concentrated in DSM than in DRM. No significant difference in the distribution of lutein and zeaxanthin was found. The obtained results suggest that in POS membranes macular xanthophylls should also be concentrated in domains enriched in polyunsaturated chains.

  8. Protein kinase C activation induces conductance changes in Hermissenda photoreceptors like those seen in associative learning.

    Farley, J; Auerbach, S

    Phosphorylation of ion channels has been suggested as one molecular mechanism responsible for learning-produced long-term changes in neuronal excitability. Persistent training-produced changes in two distinct K+ currents (IA (ref. 2), IK-Ca (refs 3,4)) and a voltage-dependent calcium current (ICa; refs 3,4) have previously been shown to occur in type B photoreceptors of Hermissenda, as a result of associative learning. But the identity of the phosphorylation pathway(s) responsible for these changes has not as yet been determined. Injections of cyclic AMP-dependent protein kinase reduce a K+ current (IK) in B cells which is different from those changed by training, but fails to reduce IA and IK-Ca. Phosphorylase b kinase (an exogenous calcium/calmodulin-dependent kinase) reduces IA, but whether IK-Ca and ICa are changed in the manner of associative training is not yet known. Another protein kinase present in high concentrations in both mammalian brain and molluscan nervous systems is protein kinase C, which is both calcium- and phospholipid-sensitive. We now present evidence that activation of protein kinase C by the tumour promoter phorbol ester (PDB) and intracellular injection of the enzyme induce conductance changes similar to those caused by associative training in Hermissenda B cells (that is a reduction of IA and IK-Ca, and enhancement of ICa). These results represent the first direct demonstration that protein kinase C affects membrane K+ ion conductance mechanisms.

  9. Stochastic resonance in an asymmetric bistable system driven by multiplicative colored noise and additive white noise

    Zhou Bingchang; Xu Wei

    2008-01-01

    The phenomenon of stochastic resonance (SR) in a bistable system driven by multiplicative colored and additive white noises and a periodic rectangular signal with a constant component is studied by using the unified colored noise approximation and the theory of signal-to-noise (SNR) in the adiabatic limit. The analytic expression of the SNR is obtained for arbitrary signal amplitude without being restricted to small amplitudes. The SNR is a non-monotonic function of intensities of multiplicative colored and additive white noises and correlation time of multiplicative colored noise, so SR exhibits in the bistable system. The effects of potential asymmetry r and correlation time τ of multiplicative colored noise on SNR are opposite. Moreover, It is more sensitive to control SR through adjusting the additive white noise intensity D than adjusting the multiplicative colored noise intensity Q

  10. Serial network simplifies the design of multiple microcomputer systems

    Folkes, D.

    1981-01-01

    Recently there has been a lot of interest in developing network communication schemes for carrying digital data between locally distributed computing stations. Many of these schemes have focused on distributed networking techniques for data processing applications. These applications suggest the use of a serial, multipoint bus, where a number of remote intelligent units act as slaves to a central or host computer. Each slave would be serially addressable from the host and would perform required operations upon being addressed by the host. Based on an MK3873 single-chip microcomputer, the SCU 20 is designed to be such a remote slave device. The capabilities of the SCU 20 and its use in systems applications are examined.

  11. Multiple-user data acquisition and analysis system

    Manzella, V.; Chrien, R.E.; Gill, R.L.; Liou, H.I.; Stelts, M.L.

    1981-01-01

    The nuclear physics program at the Brookhaven National Laboratory High Flux Beam Reactor (HFBR) employs a pair of PDP-11 computers for the dual functions of data acquisition and analysis. The data acquisition is accomplished through CAMAC and features a microprogrammed branch driver to accommodate various experimental inputs. The acquisition computer performs the functions of multi-channel analyzers, multiscaling and time-sequenced multichannel analyzers and gamma-ray coincidence analyzers. The data analysis computer is available for rapid processing of data tapes written by the acquisition computer. The ability to accommodate many users is facilitated by separating the data acquisition and analysis functions, and allowing each user to tailor the analysis to the specific requirements of his own experiment. The system is to be upgraded soon by the introduction of a dual port disk to allow a data base to be available to each computer

  12. A personal tourism navigation system to support traveling multiple destinations with time restrictions

    Maruyama, Atsushi; Shibata, Naoki; Murata, Yoshihiro; Yasumoto, Keiichi; Ito, Minoru

    2004-01-01

    We propose a personal navigation system (called PNS) which navigates a tourist through multiple destinations efficiently. In our PNS, a tourist can specify multiple destinations with desired arrival/stay time and preference degree. The system calculates the route including part of the destinations satisfying tourist's requirements and navigates him/her. For the above route search problem, we have developed an efficient route search algorithm using a genetic algorithm. We have designed and imp...

  13. ARCHITECTURE AND DYNAMICS OF KEPLER'S CANDIDATE MULTIPLE TRANSITING PLANET SYSTEMS

    Lissauer, Jack J.; Jenkins, Jon M.; Borucki, William J.; Bryson, Stephen T.; Howell, Steve B. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Ragozzine, Darin; Holman, Matthew J.; Carter, Joshua A. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Fabrycky, Daniel C.; Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Steffen, Jason H. [Fermilab Center for Particle Astrophysics, Batavia, IL 60510 (United States); Ford, Eric B. [211 Bryant Space Science Center, University of Florida, Gainesville, FL 32611 (United States); Shporer, Avi [Las Cumbres Observatory Global Telescope Network, Santa Barbara, CA 93117 (United States); Rowe, Jason F.; Quintana, Elisa V.; Caldwell, Douglas A. [SETI Institute/NASA Ames Research Center, Moffett Field, CA 94035 (United States); Batalha, Natalie M. [Department of Physics and Astronomy, San Jose State University, San Jose, CA 95192 (United States); Ciardi, David [Exoplanet Science Institute/Caltech, Pasadena, CA 91125 (United States); Dunham, Edward W. [Lowell Observatory, Flagstaff, AZ 86001 (United States); Gautier, Thomas N. III, E-mail: Jack.Lissauer@nasa.gov [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); and others

    2011-11-01

    About one-third of the {approx}1200 transiting planet candidates detected in the first four months of Kepler data are members of multiple candidate systems. There are 115 target stars with two candidate transiting planets, 45 with three, 8 with four, and 1 each with five and six. We characterize the dynamical properties of these candidate multi-planet systems. The distribution of observed period ratios shows that the vast majority of candidate pairs are neither in nor near low-order mean-motion resonances. Nonetheless, there are small but statistically significant excesses of candidate pairs both in resonance and spaced slightly too far apart to be in resonance, particularly near the 2:1 resonance. We find that virtually all candidate systems are stable, as tested by numerical integrations that assume a nominal mass-radius relationship. Several considerations strongly suggest that the vast majority of these multi-candidate systems are true planetary systems. Using the observed multiplicity frequencies, we find that a single population of planetary systems that matches the higher multiplicities underpredicts the number of singly transiting systems. We provide constraints on the true multiplicity and mutual inclination distribution of the multi-candidate systems, revealing a population of systems with multiple super-Earth-size and Neptune-size planets with low to moderate mutual inclinations.

  14. The great escape - II. Exoplanet ejection from dying multiple-star systems

    Veras, Dimitri; Tout, Christopher A.

    2012-05-01

    Extrasolar planets and belts of debris orbiting post-main-sequence single stars may become unbound as the evolving star loses mass. In multiple-star systems, the presence or co-evolution of the additional stars can significantly complicate the prospects for orbital excitation and escape. Here, we investigate the dynamical consequences of multi-phasic, non-linear mass loss and establish a criterion for a system of any stellar multiplicity to retain a planet whose orbit surrounds all of the parent stars. For single stars which become white dwarfs, this criterion can be combined with the Chandrasekhar Limit to establish the maximum allowable mass-loss rate for planet retention. We then apply the criterion to circumbinary planets in evolving binary systems over the entire stellar mass phase space. Through about 105 stellar evolutionary track realizations, we characterize planetary ejection prospects as a function of binary separation, stellar mass and metallicity. This investigation reveals that planets residing at just a few tens of au from a central concentration of stars are susceptible to escape in a wide variety of multiple systems. Further, planets are significantly more susceptible to ejection from multiple-star systems than from single-star systems for a given system mass. For system masses greater than about 2 M⊙, multiple-star systems represent the greater source of free-floating planets.

  15. Pointright: a system to redirect mouse and keyboard control among multiple machines

    Johanson, Bradley E [Palo Alto, CA; Winograd, Terry A [Stanford, CA; Hutchins, Gregory M [Mountain View, CA

    2008-09-30

    The present invention provides a software system, PointRight, that allows for smooth and effortless control of pointing and input devices among multiple displays. With PointRight, a single free-floating mouse and keyboard can be used to control multiple screens. When the cursor reaches the edge of a screen it seamlessly moves to the adjacent screen and keyboard control is simultaneously redirected to the appropriate machine. Laptops may also redirect their keyboard and pointing device, and multiple pointers are supported simultaneously. The system automatically reconfigures itself as displays go on, go off, or change the machine they display.

  16. Towards Integration of CAx Systems and a Multiple-View Product Modeller in Mechanical Design

    H. Song

    2005-01-01

    Full Text Available This paper deals with the development of an integration framework and its implementation for the connexion of CAx systems and multiple-view product modelling. The integration framework is presented regarding its conceptual level and the implementation level is described currently with the connexion of a functional modeller, a multiple-view product modeller, an optimisation module and a CAD system. The integration between the multiple-view product modeller and CATIA V5 based on the STEP standard is described in detail. Finally, the presented works are discussed and future research developments are suggested. 

  17. Dynamic information architecture system (DIAS) : multiple model simulation management

    Simunich, K. L.; Sydelko, P.; Dolph, J.; Christiansen, J.

    2002-01-01

    Dynamic Information Architecture System (DIAS) is a flexible, extensible, object-based framework for developing and maintaining complex multidisciplinary simulations of a wide variety of application contexts. The modeling domain of a specific DIAS-based simulation is determined by (1) software Entity (domain-specific) objects that represent the real-world entities that comprise the problem space (atmosphere, watershed, human), and (2) simulation models and other data processing applications that express the dynamic behaviors of the domain entities. In DIAS, models communicate only with Entity objects, never with each other. Each Entity object has a number of Parameter and Aspect (of behavior) objects associated with it. The Parameter objects contain the state properties of the Entity object. The Aspect objects represent the behaviors of the Entity object and how it interacts with other objects. DIAS extends the ''Object'' paradigm by abstraction of the object's dynamic behaviors, separating the ''WHAT'' from the ''HOW.'' DIAS object class definitions contain an abstract description of the various aspects of the object's behavior (the WHAT), but no implementation details (the HOW). Separate DIAS models/applications carry the implementation of object behaviors (the HOW). Any model deemed appropriate, including existing legacy-type models written in other languages, can drive entity object behavior. The DIAS design promotes plug-and-play of alternative models, with minimal recoding of existing applications. The DIAS Context Builder object builds a constructs or scenario for the simulation, based on developer specification and user inputs. Because DIAS is a discrete event simulation system, there is a Simulation Manager object with which all events are processed. Any class that registers to receive events must implement an event handler (method) to process the event during execution. Event handlers can schedule other events; create or remove Entities from the

  18. Dynamic information architecture system (DIAS) : multiple model simulation management.

    Simunich, K. L.; Sydelko, P.; Dolph, J.; Christiansen, J.

    2002-05-13

    Dynamic Information Architecture System (DIAS) is a flexible, extensible, object-based framework for developing and maintaining complex multidisciplinary simulations of a wide variety of application contexts. The modeling domain of a specific DIAS-based simulation is determined by (1) software Entity (domain-specific) objects that represent the real-world entities that comprise the problem space (atmosphere, watershed, human), and (2) simulation models and other data processing applications that express the dynamic behaviors of the domain entities. In DIAS, models communicate only with Entity objects, never with each other. Each Entity object has a number of Parameter and Aspect (of behavior) objects associated with it. The Parameter objects contain the state properties of the Entity object. The Aspect objects represent the behaviors of the Entity object and how it interacts with other objects. DIAS extends the ''Object'' paradigm by abstraction of the object's dynamic behaviors, separating the ''WHAT'' from the ''HOW.'' DIAS object class definitions contain an abstract description of the various aspects of the object's behavior (the WHAT), but no implementation details (the HOW). Separate DIAS models/applications carry the implementation of object behaviors (the HOW). Any model deemed appropriate, including existing legacy-type models written in other languages, can drive entity object behavior. The DIAS design promotes plug-and-play of alternative models, with minimal recoding of existing applications. The DIAS Context Builder object builds a constructs or scenario for the simulation, based on developer specification and user inputs. Because DIAS is a discrete event simulation system, there is a Simulation Manager object with which all events are processed. Any class that registers to receive events must implement an event handler (method) to process the event during execution. Event handlers

  19. Scoring systems of severity in patients with multiple trauma.

    Rapsang, Amy Grace; Shyam, Devajit Chowlek

    2015-04-01

    Trauma is a major cause of morbidity and mortality; hence severity scales are important adjuncts to trauma care in order to characterize the nature and extent of injury. Trauma scoring models can assist with triage and help in evaluation and prediction of prognosis in order to organise and improve trauma systems. Given the wide variety of scoring instruments available to assess the injured patient, it is imperative that the choice of the severity score accurately match the application. Even though trauma scores are not the key elements of trauma treatment, they are however, an essential part of improvement in triage decisions and in identifying patients with unexpected outcomes. This article provides the reader with a compendium of trauma severity scales along with their predicted death rate calculation, which can be adopted in order to improve decision making, trauma care, research and in comparative analyses in quality assessment. Copyright © 2013 AEC. Publicado por Elsevier España, S.L.U. All rights reserved.

  20. Multiple-feature extracting modules based leak mining system design.

    Cho, Ying-Chiang; Pan, Jen-Yi

    2013-01-01

    Over the years, human dependence on the Internet has increased dramatically. A large amount of information is placed on the Internet and retrieved from it daily, which makes web security in terms of online information a major concern. In recent years, the most problematic issues in web security have been e-mail address leakage and SQL injection attacks. There are many possible causes of information leakage, such as inadequate precautions during the programming process, which lead to the leakage of e-mail addresses entered online or insufficient protection of database information, a loophole that enables malicious users to steal online content. In this paper, we implement a crawler mining system that is equipped with SQL injection vulnerability detection, by means of an algorithm developed for the web crawler. In addition, we analyze portal sites of the governments of various countries or regions in order to investigate the information leaking status of each site. Subsequently, we analyze the database structure and content of each site, using the data collected. Thus, we make use of practical verification in order to focus on information security and privacy through black-box testing.

  1. Influences of multiple memory systems on auditory mental image acuity.

    Navarro Cebrian, Ana; Janata, Petr

    2010-05-01

    The influence of different memory systems and associated attentional processes on the acuity of auditory images, formed for the purpose of making intonation judgments, was examined across three experiments using three different task types (cued-attention, imagery, and two-tone discrimination). In experiment 1 the influence of implicit long-term memory for musical scale structure was manipulated by varying the scale degree (leading tone versus tonic) of the probe note about which a judgment had to be made. In experiments 2 and 3 the ability of short-term absolute pitch knowledge to develop was manipulated by presenting blocks of trials in the same key or in seven different keys. The acuity of auditory images depended on all of these manipulations. Within individual listeners, thresholds in the two-tone discrimination and cued-attention conditions were closely related. In many listeners, cued-attention thresholds were similar to thresholds in the imagery condition, and depended on the amount of training individual listeners had in playing a musical instrument. The results indicate that mental images formed at a sensory/cognitive interface for the purpose of making perceptual decisions are highly malleable.

  2. Shaggy Photoreceptors with Subfoveal Fluid Associated with a Distant Choroidal Melanoma

    Ann Q. Tran

    2015-01-01

    Full Text Available Purpose. To describe the enhanced depth imaging optical coherence tomography (EDI-OCT findings in a patient with an extra macula choroidal melanoma before and after treatment. Methods. Observational case report. Results. A 45 year-old Caucasian male patient was referred to retina clinic for management of choroidal melanoma. Examination revealed a nasal choroidal melanoma while EDI-OCT illustrated subfoveal fluid pocket with elongated shaggy photoreceptors distant and separate from the tumor. The patient was treated with plaque brachytherapy and intravitreal bevacizumab. One week after plaque removal, there was a dramatic reduction in the shaggy photoreceptors. Conclusion. Choroidal melanomas have effects that are not localized to the area of the tumor. This loculated pocket of subretinal fluid and coinciding changes to photoreceptor morphology may be related to global changes in choroidal function or release of tumor related cytokines.

  3. UV-B Perceived by the UVR8 Photoreceptor Inhibits Plant Thermomorphogenesis.

    Hayes, Scott; Sharma, Ashutosh; Fraser, Donald P; Trevisan, Martine; Cragg-Barber, C Kester; Tavridou, Eleni; Fankhauser, Christian; Jenkins, Gareth I; Franklin, Keara A

    2017-01-09

    Small increases in ambient temperature can elicit striking effects on plant architecture, collectively termed thermomorphogenesis [1]. In Arabidopsis thaliana, these include marked stem elongation and leaf elevation, responses that have been predicted to enhance leaf cooling [2-5]. Thermomorphogenesis requires increased auxin biosynthesis, mediated by the bHLH transcription factor PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) [6-8], and enhanced stability of the auxin co-receptor TIR1, involving HEAT SHOCK PROTEIN 90 (HSP90) [9]. High-temperature-mediated hypocotyl elongation additionally involves localized changes in auxin metabolism, mediated by the indole-3-acetic acid (IAA)-amido synthetase Gretchen Hagen 3 (GH3).17 [10]. Here we show that ultraviolet-B light (UV-B) perceived by the photoreceptor UV RESISTANCE LOCUS 8 (UVR8) [11] strongly attenuates thermomorphogenesis via multiple mechanisms inhibiting PIF4 activity. Suppression of thermomorphogenesis involves UVR8 and CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1)-mediated repression of PIF4 transcript accumulation, reducing PIF4 abundance. UV-B also stabilizes the bHLH protein LONG HYPOCOTYL IN FAR RED (HFR1), which can bind to and inhibit PIF4 function. Collectively, our results demonstrate complex crosstalk between UV-B and high-temperature signaling. As plants grown in sunlight would most likely experience concomitant elevations in UV-B and ambient temperature, elucidating how these pathways are integrated is of key importance to the understanding of plant development in natural environments. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. Guided Multiple Launch Rocket System/Guided Multiple Launch Rocket System Alternative Warhead (GMLRS/GMLRS AW)

    2015-12-01

    Physical Configuration Audit for the GMLRS AW was completed at the system level in March 2015. ​Director of Operational Test and Evaluation Assessment...Confidence Level Confidence Level of cost estimate for current APB: 50% The confidence level used in establishing the cost estimate for GMLRS/GMLRS AW...PAUC Development Estimate Changes PAUC Production Estimate Econ Qty Sch Eng Est Oth Spt Total 0.039 -0.003 0.001 0.001 0.009 0.037 0.000 0.000 0.045

  5. Hybrid digital-analog video transmission in wireless multicast and multiple-input multiple-output system

    Liu, Yu; Lin, Xiaocheng; Fan, Nianfei; Zhang, Lin

    2016-01-01

    Wireless video multicast has become one of the key technologies in wireless applications. But the main challenge of conventional wireless video multicast, i.e., the cliff effect, remains unsolved. To overcome the cliff effect, a hybrid digital-analog (HDA) video transmission framework based on SoftCast, which transmits the digital bitstream with the quantization residuals, is proposed. With an effective power allocation algorithm and appropriate parameter settings, the residual gains can be maximized; meanwhile, the digital bitstream can assure transmission of a basic video to the multicast receiver group. In the multiple-input multiple-output (MIMO) system, since nonuniform noise interference on different antennas can be regarded as the cliff effect problem, ParCast, which is a variation of SoftCast, is also applied to video transmission to solve it. The HDA scheme with corresponding power allocation algorithms is also applied to improve video performance. Simulations show that the proposed HDA scheme can overcome the cliff effect completely with the transmission of residuals. What is more, it outperforms the compared WSVC scheme by more than 2 dB when transmitting under the same bandwidth, and it can further improve performance by nearly 8 dB in MIMO when compared with the ParCast scheme.

  6. Multiple bio-monitoring system using visible light for electromagnetic-wave free indoor healthcare

    An, Jinyoung; Pham, Ngoc Quan; Chung, Wan-Young

    2017-12-01

    In this paper, a multiple biomedical data transmission system with visible light communication (VLC) is proposed for an electromagnetic-wave-free indoor healthcare. VLC technology has emerged as an alternative solution to radio-frequency (RF) wireless systems, due to its various merits, e.g., ubiquity, power efficiency, no RF radiation, and security. With VLC, critical bio-medical signals, including electrocardiography (ECG), can be transmitted in places where RF radiation is restricted. This potential advantage of VLC could save more lives in emergency situations. A time hopping (TH) scheme is employed to transfer multiple medical-data streams in real time with a simple system design. Multiple data streams are transmitted using identical color LEDs and go into an optical detector. The received multiple data streams are demodulated and rearranged using a TH-based demodulator. The medical data is then monitored and managed to provide the necessary medical care for each patient.

  7. Seismic response analysis of structural system subjected to multiple support excitation

    Wu, R.W.; Hussain, F.A.; Liu, L.K.

    1978-01-01

    In the seismic analysis of a multiply supported structural system subjected to nonuniform excitations at each support point, the single response spectrum, the time history, and the multiple response spectrum are the three commonly employed methods. In the present paper the three methods are developed, evaluated, and the limitations and advantages of each method assessed. A numerical example has been carried out for a typical piping system. Considerably smaller responses have been predicted by the time history method than that by the single response spectrum method. This is mainly due to the fact that the phase and amplitude relations between the support excitations are faithfully retained in the time history method. The multiple response spectrum prediction has been observed to compare favourably with the time history method prediction. Based on the present evaluation, the multiple response spectrum method is the most efficient method for seismic response analysis of structural systems subjected to multiple support excitation. (Auth.)

  8. Turning challenges into design principles: Telemonitoring systems for patients with multiple chronic conditions.

    Sultan, Mehwish; Kuluski, Kerry; McIsaac, Warren J; Cafazzo, Joseph A; Seto, Emily

    2018-01-01

    People with multiple chronic conditions often struggle with managing their health. The purpose of this research was to identify specific challenges of patients with multiple chronic conditions and to use the findings to form design principles for a telemonitoring system tailored for these patients. Semi-structured interviews with 15 patients with multiple chronic conditions and 10 clinicians were conducted to gain an understanding of their needs and preferences for a smartphone-based telemonitoring system. The interviews were analyzed using a conventional content analysis technique, resulting in six themes. Design principles developed from the themes included that the system must be modular to accommodate various combinations of conditions, reinforce a routine, consolidate record keeping, as well as provide actionable feedback to the patients. Designing an application for multiple chronic conditions is complex due to variability in patient conditions, and therefore, design principles developed in this study can help with future innovations aimed to help manage this population.

  9. Analysis of macular cone photoreceptors in a case of occult macular dystrophy

    Tojo N

    2013-05-01

    Full Text Available Naoki Tojo Tomoko Nakamura Hironori Ozaki Miyako Oka Toshihiko Oiwake Atsushi HayashiDepartment of Ophthalmology, University of Toyama, Toyama, JapanPurpose: To investigate changes in cone photoreceptors with adaptive optics (AO fundus imaging and spectral domain optical coherence tomography (SD-OCT in a case of occult macular dystrophy (OMD.Patient and methods: Both eyes of a 42-year-old woman diagnosed with OMD were examined. We used an AO fundus camera to obtain images of cone photoreceptors in the macula of the OMD subject and five healthy control subjects. Correlations between the AO images and the SD-OCT images were examined. Cone photoreceptors in eight areas in the macula of OMD and healthy control subjects were analyzed and compared.Results: SD-OCT showed a loss of the cone outer-segment tips line outside of the fovea in both eyes of the subject with OMD. The left eye with decreased visual acuity showed a discontinuous photoreceptor inner-segment and outer-segment line and cone outer-segment tips line at the fovea in SD-OCT and loss of cone mosaics as a dark spot in the AO image. In panoramic AO images and cone-density maps, less cone density was observed in a ring-like region outside the fovea than in the peripheral retina. In most of the areas examined, the cone densities were lower in the OMD eyes than in the healthy control eyes.Conclusions: Cone densities in the macula of the OMD patient were greatly decreased. AO images were found to be useful to evaluate morphologic changes in cone photoreceptors in patients with OMD.Keywords: occult macular dystrophy, adaptive optics, cone photoreceptor, cone analysis, optical coherence tomography

  10. Edaravone, an ROS Scavenger, Ameliorates Photoreceptor Cell Death after Experimental Retinal Detachment

    Roh, Mi In; Murakami, Yusuke; Thanos, Aristomenis; Miller, Joan W.

    2011-01-01

    Purpose. To investigate whether edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one), a free radical scavenger, would be neuroprotective against photoreceptor cell death in a rat model of retinal detachment (RD). Methods. RD was induced in adult Brown Norway rats by subretinal injection of sodium hyaluronate. Edaravone (3, 5, or 10 mg/kg) or physiologic saline was administered intraperitoneally once a day until death on day 3 or 5. Oxidative stress in the retina was assessed by 4-hydroxynonenal staining or ELISA for protein carbonyl content. Photoreceptor death was assessed by TUNEL and measurement of the outer nuclear layer thickness. Western blot analysis and caspase activity assays were performed. Inflammatory cytokine secretion and inflammatory cell infiltration were evaluated by ELISA and immunostaining, respectively. Results. RD resulted in increased generation of ROS. Treatment with 5 mg/kg edaravone significantly reduced the ROS level, along with a decrease in TUNEL-positive cells in the photoreceptor layer. A caspase assay also confirmed decreased activation of caspase-3, -8, and -9 in RD treated with edaravone. The level of the antiapoptotic Bcl-2 was increased in detached retinas after edaravone treatment, whereas the levels of the stress-activated p-ERK1/2 were decreased. In addition, edaravone treatment resulted in a significant decrease in the levels of TNF-α, MCP-1, and macrophage infiltration. Conclusions. Oxidative stress plays an important role in photoreceptor cell death after RD. Edaravone treatment may aid in preventing photoreceptor cell death after RD by suppressing ROS-induced photoreceptor damage. PMID:21310909

  11. Adaptive optics fundus images of cone photoreceptors in the macula of patients with retinitis pigmentosa

    Tojo N

    2013-01-01

    Full Text Available Naoki Tojo, Tomoko Nakamura, Chiharu Fuchizawa, Toshihiko Oiwake, Atsushi HayashiDepartment of Ophthalmology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, JapanBackground: The purpose of this study was to examine cone photoreceptors in the macula of patients with retinitis pigmentosa using an adaptive optics fundus camera and to investigate any correlations between cone photoreceptor density and findings on optical coherence tomography and fundus autofluorescence.Methods: We examined two patients with typical retinitis pigmentosa who underwent ophthalmological examination, including measurement of visual acuity, and gathering of electroretinographic, optical coherence tomographic, fundus autofluorescent, and adaptive optics fundus images. The cone photoreceptors in the adaptive optics images of the two patients with retinitis pigmentosa and five healthy subjects were analyzed.Results: An abnormal parafoveal ring of high-density fundus autofluorescence was observed in the macula in both patients. The border of the ring corresponded to the border of the external limiting membrane and the inner segment and outer segment line in the optical coherence tomographic images. Cone photoreceptors at the abnormal parafoveal ring were blurred and decreased in the adaptive optics images. The blurred area corresponded to the abnormal parafoveal ring in the fundus autofluorescence images. Cone densities were low at the blurred areas and at the nasal and temporal retina along a line from the fovea compared with those of healthy controls. The results for cone spacing and Voronoi domains in the macula corresponded with those for the cone densities.Conclusion: Cone densities were heavily decreased in the macula, especially at the parafoveal ring on high-density fundus autofluorescence in both patients with retinitis pigmentosa. Adaptive optics images enabled us to observe in vivo changes in the cone photoreceptors of

  12. Rip3 knockdown rescues photoreceptor cell death in blind pde6c zebrafish.

    Viringipurampeer, I A; Shan, X; Gregory-Evans, K; Zhang, J P; Mohammadi, Z; Gregory-Evans, C Y

    2014-05-01

    Achromatopsia is a progressive autosomal recessive retinal disease characterized by early loss of cone photoreceptors and later rod photoreceptor loss. In most cases, mutations have been identified in CNGA3, CNGB3, GNAT2, PDE6C or PDE6H genes. Owing to this genetic heterogeneity, mutation-independent therapeutic schemes aimed at preventing cone cell death are very attractive treatment strategies. In pde6c(w59) mutant zebrafish, cone photoreceptors expressed high levels of receptor-interacting protein kinase 1 (RIP1) and receptor-interacting protein kinase 3 (RIP3) kinases, key regulators of necroptotic cell death. In contrast, rod photoreceptor cells were alternatively immunopositive for caspase-3 indicating activation of caspase-dependent apoptosis in these cells. Morpholino gene knockdown of rip3 in pde6c(w59) embryos rescued the dying cone photoreceptors by inhibiting the formation of reactive oxygen species and by inhibiting second-order neuron remodelling in the inner retina. In rip3 morphant larvae, visual function was restored in the cones by upregulation of the rod phosphodiesterase genes (pde6a and pde6b), compensating for the lack of cone pde6c suggesting that cones are able to adapt to their local environment. Furthermore, we demonstrated through pharmacological inhibition of RIP1 and RIP3 activity that cone cell death was also delayed. Collectively, these results demonstrate that the underlying mechanism of cone cell death in the pde6c(w59) mutant retina is through necroptosis, whereas rod photoreceptor bystander death occurs through a caspase-dependent mechanism. This suggests that targeting the RIP kinase signalling pathway could be an effective therapeutic intervention in retinal degeneration patients. As bystander cell death is an important feature of many retinal diseases, combinatorial approaches targeting different cell death pathways may evolve as an important general principle in treatment.

  13. Lrit1, a Retinal Transmembrane Protein, Regulates Selective Synapse Formation in Cone Photoreceptor Cells and Visual Acuity.

    Ueno, Akiko; Omori, Yoshihiro; Sugita, Yuko; Watanabe, Satoshi; Chaya, Taro; Kozuka, Takashi; Kon, Tetsuo; Yoshida, Satoyo; Matsushita, Kenji; Kuwahara, Ryusuke; Kajimura, Naoko; Okada, Yasushi; Furukawa, Takahisa

    2018-03-27

    In the vertebrate retina, cone photoreceptors play crucial roles in photopic vision by transmitting light-evoked signals to ON- and/or OFF-bipolar cells. However, the mechanisms underlying selective synapse formation in the cone photoreceptor pathway remain poorly understood. Here, we found that Lrit1, a leucine-rich transmembrane protein, localizes to the photoreceptor synaptic terminal and regulates the synaptic connection between cone photoreceptors and cone ON-bipolar cells. Lrit1-deficient retinas exhibit an aberrant morphology of cone photoreceptor pedicles, as well as an impairment of signal transmission from cone photoreceptors to cone ON-bipolar cells. Furthermore, we demonstrated that Lrit1 interacts with Frmpd2, a photoreceptor scaffold protein, and with mGluR6, an ON-bipolar cell-specific glutamate receptor. Additionally, Lrit1-null mice showed visual acuity impairments in their optokinetic responses. These results suggest that the Frmpd2-Lrit1-mGluR6 axis regulates selective synapse formation in cone photoreceptors and is essential for normal visual function. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

  14. Interaction of two photoreceptors in the regulation of bacterial photosynthesis genes

    Metz, Sebastian; Haberzettl, Kerstin; Frühwirth, Sebastian; Teich, Kristin; Hasewinkel, Christian; Klug, Gabriele

    2012-01-01

    The expression of photosynthesis genes in the facultatively photosynthetic bacterium Rhodobacter sphaeroides is controlled by the oxygen tension and by light quantity. Two photoreceptor proteins, AppA and CryB, have been identified in the past, which are involved in this regulation. AppA senses light by its N-terminal BLUF domain, its C-terminal part binds heme and is redox-responsive. Through its interaction to the transcriptional repressor PpsR the AppA photoreceptor controls expression of ...

  15. No evidence for a genetic blueprint: The case of the "complex" mammalian photoreceptor

    G Kumaramanickavel

    2015-01-01

    Full Text Available Despite the intensity of the search for genes causing inherited retinal degenerations over the past 3 decades, of the approximately 200 disease genes identified to date, all appear to be ordinary housekeeping genes specifying proteins playing basic structural and functional roles in the mature photoreceptor cells. No genes or genetic elements have been identified which can be construed as having a specific morphogenic role, directing the development of the cytoarchitecture of any particular retinal cell. The evidence suggests that the cytoarchitecture of the retinal photoreceptors, although enormously complex, arises from the self-organization of the cells constituents without any regulation or direction from an external genetic blueprint.

  16. Machine learning approaches to supporting the identification of photoreceptor-enriched genes based on expression data

    Simpson David

    2006-03-01

    Full Text Available Abstract Background Retinal photoreceptors are highly specialised cells, which detect light and are central to mammalian vision. Many retinal diseases occur as a result of inherited dysfunction of the rod and cone photoreceptor cells. Development and maintenance of photoreceptors requires appropriate regulation of the many genes specifically or highly expressed in these cells. Over the last decades, different experimental approaches have been developed to identify photoreceptor enriched genes. Recent progress in RNA analysis technology has generated large amounts of gene expression data relevant to retinal development. This paper assesses a machine learning methodology for supporting the identification of photoreceptor enriched genes based on expression data. Results Based on the analysis of publicly-available gene expression data from the developing mouse retina generated by serial analysis of gene expression (SAGE, this paper presents a predictive methodology comprising several in silico models for detecting key complex features and relationships encoded in the data, which may be useful to distinguish genes in terms of their functional roles. In order to understand temporal patterns of photoreceptor gene expression during retinal development, a two-way cluster analysis was firstly performed. By clustering SAGE libraries, a hierarchical tree reflecting relationships between developmental stages was obtained. By clustering SAGE tags, a more comprehensive expression profile for photoreceptor cells was revealed. To demonstrate the usefulness of machine learning-based models in predicting functional associations from the SAGE data, three supervised classification models were compared. The results indicated that a relatively simple instance-based model (KStar model performed significantly better than relatively more complex algorithms, e.g. neural networks. To deal with the problem of functional class imbalance occurring in the dataset, two data re

  17. Reduced α-stable dynamics for multiple time scale systems forced with correlated additive and multiplicative Gaussian white noise

    Thompson, William F.; Kuske, Rachel A.; Monahan, Adam H.

    2017-11-01

    Stochastic averaging problems with Gaussian forcing have been the subject of numerous studies, but far less attention has been paid to problems with infinite-variance stochastic forcing, such as an α-stable noise process. It has been shown that simple linear systems driven by correlated additive and multiplicative (CAM) Gaussian noise, which emerge in the context of reduced atmosphere and ocean dynamics, have infinite variance in certain parameter regimes. In this study, we consider the stochastic averaging of systems where a linear CAM noise process in the infinite variance parameter regime drives a comparatively slow process. We use (semi)-analytical approximations combined with numerical illustrations to compare the averaged process to one that is forced by a white α-stable process, demonstrating consistent properties in the case of large time-scale separation. We identify the conditions required for the fast linear CAM process to have such an influence in driving a slower process and then derive an (effectively) equivalent fast, infinite-variance process for which an existing stochastic averaging approximation is readily applied. The results are illustrated using numerical simulations of a set of example systems.

  18. Analysis of the function of the photoreceptors phytochrome B and phytochrome D in Nicotiana plumbaginifolia and Arabidopsis thaliana.

    Fernández, Aurora Piñas; Gil, Patricia; Valkai, Ildiko; Nagy, Ferenc; Schäfer, Eberhard

    2005-05-01

    To investigate the mechanism of phytochrome action in vivo, NtPHYB, AtPHYB and phyD:green fluorescent protein (GFP) were overexpressed in Nicotiana plumbaginifolia and Arabidopsis thaliana. The expression of 35S:NtPHYB:GFP and 35S:AtPHYB:GFP complemented the tobacco hgl2 and Arabidopsis phyB-9 mutations, whereas the 35S:AtPHYD:GFP only rescued the hgl2 mutant. All three fusion proteins are transported into the nucleus in all genetic backgrounds. These data indicate that AtPHYD:GFP is biologically active and functions as the main red light receptor in transgenic tobacco, and establish an experimental system for the functional analysis of this elusive photoreceptor in vivo.

  19. Second-Order Controllability of Multi-Agent Systems with Multiple Leaders

    Liu Bo; Han Xiao; Shi Yun-Tao; Su Hou-Sheng

    2016-01-01

    This paper proposes a new second-order continuous-time multi-agent model and analyzes the controllability of second-order multi-agent system with multiple leaders based on the asymmetric topology. This paper considers the more general case: velocity coupling topology is different from location coupling topology. Some sufficient and necessary conditions are presented for the controllability of the system with multiple leaders. In addition, the paper studies the controllability of the system with velocity damping gain. Simulation results are given to illustrate the correctness of theoretical results. (paper)

  20. Availability of thermodynamic system with multiple performance parameters based on vector-universal generating function

    Cai Qi; Shang Yanlong; Chen Lisheng; Zhao Yuguang

    2013-01-01

    Vector-universal generating function was presented to analyze the availability of thermodynamic system with multiple performance parameters. Vector-universal generating function of component's performance was defined, the arithmetic model based on vector-universal generating function was derived for the thermodynamic system, and the calculation method was given for state probability of multi-state component. With the stochastic simulation of the degeneration trend of the multiple factors, the system availability with multiple performance parameters was obtained under composite factors. It is shown by an example that the results of the availability obtained by the binary availability analysis method are somewhat conservative, and the results considering parameter failure based on vector-universal generating function reflect the operation characteristics of the thermodynamic system better. (authors)

  1. Heat Recovery from Multiple-Fracture Enhanced Geothermal Systems: The Effect of Thermoelastic Fracture Interactions

    Vik, Hedda Slatlem; Salimzadeh, Saeed; Nick, Hamid

    2018-01-01

    This study investigates the effect of thermoelastic interactions between multiple parallel fractures on energy production from a multiple-fracture enhanced geothermal system. A coupled thermo-hydro-mechanical finite element model has been developed that accounts for non-isothermal fluid flow within...... increased to maximise the net energy production from the system. Otherwise, the multiple-fracture system fails to improve the energy recovery from the geothermal reservoir, as initially intended....... aperture in the adjacent fracture, and facilitates the creation of favourable flow pathways between the injection and production wells. These flow paths reduce the energy production from the system. The effects of fracture spacing, reservoir temperature gradient and mechanical properties of the rock matrix...

  2. Optimized production planning model for a multi-plant cultivation system under uncertainty

    Ke, Shunkui; Guo, Doudou; Niu, Qingliang; Huang, Danfeng

    2015-02-01

    An inexact multi-constraint programming model under uncertainty was developed by incorporating a production plan algorithm into the crop production optimization framework under the multi-plant collaborative cultivation system. In the production plan, orders from the customers are assigned to a suitable plant under the constraints of plant capabilities and uncertainty parameters to maximize profit and achieve customer satisfaction. The developed model and solution method were applied to a case study of a multi-plant collaborative cultivation system to verify its applicability. As determined in the case analysis involving different orders from customers, the period of plant production planning and the interval between orders can significantly affect system benefits. Through the analysis of uncertain parameters, reliable and practical decisions can be generated using the suggested model of a multi-plant collaborative cultivation system.

  3. Design of pulse waveform for waveform division multiple access UWB wireless communication system.

    Yin, Zhendong; Wang, Zhirui; Liu, Xiaohui; Wu, Zhilu

    2014-01-01

    A new multiple access scheme, Waveform Division Multiple Access (WDMA) based on the orthogonal wavelet function, is presented. After studying the correlation properties of different categories of single wavelet functions, the one with the best correlation property will be chosen as the foundation for combined waveform. In the communication system, each user is assigned to different combined orthogonal waveform. Demonstrated by simulation, combined waveform is more suitable than single wavelet function to be a communication medium in WDMA system. Due to the excellent orthogonality, the bit error rate (BER) of multiuser with combined waveforms is so close to that of single user in a synchronous system. That is to say, the multiple access interference (MAI) is almost eliminated. Furthermore, even in an asynchronous system without multiuser detection after matched filters, the result is still pretty ideal and satisfactory by using the third combination mode that will be mentioned in the study.

  4. PC-based Multiple Information System Interface (PC/MISI) design plan

    Dominick, Wayne D. (Editor); Hall, Philip P.

    1985-01-01

    The general design plan for the implementation of a common user interface to multiple remote information systems within a microcomputer-based environment is presented. The intent is to provide a framework for the development of detailed specifications which will be used as guidelines for the actual development of the system.

  5. A Methodology for Multiple Rule System Integration and Resolution Within a Singular Knowledge Base

    Kautzmann, Frank N., III

    1988-01-01

    Expert Systems which support knowledge representation by qualitative modeling techniques experience problems, when called upon to support integrated views embodying description and explanation, especially when other factors such as multiple causality, competing rule model resolution, and multiple uses of knowledge representation are included. A series of prototypes are being developed to demonstrate the feasibility of automating the process of systems engineering, design and configuration, and diagnosis and fault management. A study involves not only a generic knowledge representation; it must also support multiple views at varying levels of description and interaction between physical elements, systems, and subsystems. Moreover, it will involve models of description and explanation for each level. This multiple model feature requires the development of control methods between rule systems and heuristics on a meta-level for each expert system involved in an integrated and larger class of expert system. The broadest possible category of interacting expert systems is described along with a general methodology for the knowledge representation and control of mutually exclusive rule systems.

  6. Cognitive Multiple-Antenna Network with Outage and Rate Margins at the Primary System

    Maham, Behrouz; Popovski, Petar

    2015-01-01

    In the common model for spectrum sharing, cognitive users can access the spectrum as long as the target performance in the legitimate primary system is not violated. In this paper, we consider a downlink primary multiple-inputsingle- output (MISO) system which operates under a controlled interfer...

  7. Multiple Memory Systems Are Unnecessary to Account for Infant Memory Development: An Ecological Model

    Rovee-Collier, Carolyn; Cuevas, Kimberly

    2009-01-01

    How the memory of adults evolves from the memory abilities of infants is a central problem in cognitive development. The popular solution holds that the multiple memory systems of adults mature at different rates during infancy. The "early-maturing system" (implicit or nondeclarative memory) functions automatically from birth, whereas the…

  8. Misalignment of outflow axes in the proto-multiple systems in Perseus

    Lee, Katherine I.; Dunham, Michael M.; Myers, Philip C.

    2016-01-01

    We investigate the alignment between outflow axes in nine of the youngest binary/multiple systems in the Perseus Molecular Cloud. These systems have typical member spacing larger than 1000 au. For outflow identification, we use 12CO(2-1) and 12CO(3-2) data from a large survey with the Submillimet...

  9. High-speed multiple-channel analog to digital data-acquisition module for microprocessor systems

    Ethridge, C.D.

    1977-01-01

    Intelligent data acquisition and instrumentation systems established by the incorporation of microprocessor technology require high-speed analog to digital conversion of multiple-channel input signals. Sophisticated data systems or subsystems are enabled by the microprocessor software flexibility to establish adaptive input data procedures. These adaptive procedures are enhanced by versatile interface circuitry which is software controlled

  10. A wireless body measurement system to study fatigue in multiple sclerosis

    Yu, F.; Bilberg, A.; Stenager, E.; Rabotti, C.; Zhang, B.; Mischi, M.

    2012-01-01

    Fatigue is reported as the most common symptom by patients with multiple sclerosis (MS). The physiological and functional parameters related to fatigue in MS patients are currently not well established. A new wearable wireless body measurement system, named Fatigue Monitoring System (FAMOS), was

  11. Porting of the DBCSR library for Sparse Matrix-Matrix Multiplications to Intel Xeon Phi systems

    Bethune, Iain; Gloess, Andeas; Hutter, Juerg; Lazzaro, Alfio; Pabst, Hans; Reid, Fiona

    2017-01-01

    Multiplication of two sparse matrices is a key operation in the simulation of the electronic structure of systems containing thousands of atoms and electrons. The highly optimized sparse linear algebra library DBCSR (Distributed Block Compressed Sparse Row) has been specifically designed to efficiently perform such sparse matrix-matrix multiplications. This library is the basic building block for linear scaling electronic structure theory and low scaling correlated methods in CP2K. It is para...

  12. Power Factor Correction Capacitors for Multiple Parallel Three-Phase ASD Systems

    Yang, Yongheng; Blaabjerg, Frede

    2017-01-01

    Today’s three-phase Adjustable Speed Drive (ASD) systems still employ Diode Rectifiers (DRs) and Silicon-Controlled Rectifiers (SCRs) as the front-end converters due to structural and control simplicity, small volume, low cost, and high reliability. However, the uncontrollable DRs and phase......-controllable SCRs bring side-effects by injecting high harmonics to the grid, which will degrade the system performance in terms of lowering the overall efficiency and overheating the system if remain uncontrolled or unattenuated. For multiple ASD systems, certain harmonics in the entire system can be mitigated...... the power factor, passive capacitors can be installed, which yet can trigger the system resonance. Hence, this paper analyzes the resonant issues in multiple ASD systems with power factor correction capacitors. Potential damping solutions are summarized. Simulations are carried out, while laboratory tests...

  13. Multiple myeloma and central nervous system involvement: experience of a Brazilian center

    Ana Luiza Miranda Silva Dias

    2018-01-01

    Full Text Available Introduction: The estimated involvement of the central nervous system in patients with multiple myeloma is rare at about 1%. The infiltration can be identified at the time multiple myeloma is diagnosed or during its progression. However, it is more common in refractory disease or during relapse. Methods: This retrospective cohort study reviewed data from medical records of patients followed up at the Gammopathy Outpatient Clinic of Santa Casa de Misericórdia de São Paulo from January 2008 to December 2016. Results: Twenty patients were included, with a median follow-up of 33.5 months after central nervous system infiltration. The prevalence was 7%. The median age at diagnosis of multiple myeloma was 56.1 years, with 70% of participants being female. Sixteen patients had central nervous system infiltration at diagnosis of multiple myeloma. Seventeen patients had exclusive osteodural lesions and three had infiltrations of the leptomeninge, of which one had exclusive involvement and two had associated osteodural lesions. The median overall survival was 40.3 months after central nervous system involvement. The median overall survival in the group with central nervous system infiltration at relapse was 7.4 months. The patients with leptomeningeal involvement had a median overall survival of 5.8 months. Conclusion: Central nervous system infiltration is a rare condition, but it should be considered as a possibility in patients with multiple myeloma and neurological symptoms. The best treatment regimen for this condition remains unknown and, in most cases, the prognosis is unfavorable. Keywords: Central nervous system, Multiple myeloma, Radiotherapy, Chemotherapy, Prognosis

  14. Systems of Selves: the Construction of Meaning in Multiple Personality Disorder

    Hughes, Dureen Jean

    Current models for understanding both Multiple Personality Disorder and human mentation in general are both linear in nature and self-perpetuating insofar as most research in this area has been informed and shaped by extant psychological concepts, paradigms and methods. The research for this dissertation made use of anthropological concepts and methods in an attempt to gain a richer understanding of both multiple personality and fundamental universal processes of the mind. Intensive fieldwork using in-depth, open-ended interviewing techniques was conducted with people diagnosed with Multiple Personality Disorder with the purpose of mapping their personality systems in order to discover the nature of the relationships between the various alternate personalities and subsystems comprising the overall personality systems. These data were then analyzed in terms of dynamical systems theory ("Chaos Theory") as a way of understanding various phenomena of multiple personality disorder as well as the overall structure of each system. It was found that the application of the formal characteristics of nonlinear models and equations to multiple personality systems provided a number of new perspectives on mental phenomena. The underlying organizational structure of multiple personality systems can be understood as a phenomenon of spontaneous self-organization in far-from -equilibrium states which characterizes dissipative structures. Chaos Theory allows the perspective that the nature of the process of the self and the nature of relationship are one and the same, and that both can be conceived as ideas in struggle at a fractal boundary. Further, such application makes it possible to postulate an iterative process which would have as one of its consequences the formation of a processural self who is conscious of self as separate self. Finally, given that the iterative application of a few simple rules (or instructions) can result in complex systems, an attempt was made to discern

  15. Studies concerning the photoreceptor pigments of stentor coeruleus and blepharisma japonicum

    Dax, T.G.

    2000-05-01

    In the presence of 1,8-bis-(dimethylamino)-naphthalene, solutions of 3-O-benzyl hypericin and 3,4-di-O-benzyl hypericin in aromatic solvents like benzene or toluene have shown to be photoreactive, whereas in the dark no reactions occurred. 3-O-benzyl hypericin was found to enter a photorearrangement reaction leading to a product species, whose structural details could be elicited by UV/VIS, NMR, and mass spectroscopy together with spectrophotometric titrations. Investigation results led to a 11-phenyl-11H-benz{4,10}anthra{2,1,9,8-nopqa}pleiadene skeleton forming the backbone of the photoproduct. This fundamental system is the more of interest since it highly resembles the parent compound of the blepharismins, the photoreceptor pigments of Blepharisma japonicum. In analogy to blepharismin C, which can be converted photochemically into oxyblepharismin C and further on into stentorin by treatment with acid, the photoproduct could be transformed into hypericin upon irradiation and additional acidic work up. As the photoproduct incorporates several equilibrium systems, computer aided calculations were executed to achieve an idea about the relative stability of the photoproduct's various isomeric forms. The described photoreaction represents a possible route for the total synthesis of blepharismins and oxyblepharismins. Furthermore, it could shed some light on the biogenesis of these photosensing pigments. Irradiation of 3,4-di-O-benzyl hypericin in benzene solution together with a large excess of 1,8-bis-(dimethylamino)-naphthalene produced a species exhibiting a tremendous absorption band in the near IR. By means of EPR spectroscopy it could be stated that this primary photoproduct was of radical nature. The product was examined by means of UV/VIS, NMR, IR and mass spectroscopy. (author)

  16. The xanthopsins : a new family of eubacterial blue-light photoreceptors

    Kort, R; Hoff, W.D.; West, M.E.; Kroon, A R; Hoffer, S.M.; Vlieg, K H; Crielaand, W; van Beeumen, J.; Hellingwerf, K J

    1996-01-01

    Photoactive yellow protein (PYP) is a photoreceptor that has been isolated from three halophilic phototrophic purple bacteria. The PYP from Ectothiorhodospira halophila BN9626 is the only member for which the sequence has been reported at the DNA level. Here we describe the cloning and sequencing of

  17. The Xanthopsins: a new family of eubacterial blue-light photoreceptors

    Kort, R.; Hoff, W.D.; van West, W.S.; Kroon, A.R.; Hoffer, S.M.; Vlieg, K.H.; Crielaard, W.; van Beeumen, J.J.; Hellingwerf, K.J.

    1996-01-01

    Photoactive yellow protein (PYP) is a photoreceptor that has been isolated from three halophilic phototrophic purple bacteria. The PYP from Ectothiorhodospira halophila BN9626 is the only member for which the sequence has been reported at the DNA level. Here we describe the cloning and sequencing of

  18. Melanopsin-expressing amphioxus photoreceptors transduce light via a phospholipase C signaling cascade.

    Juan Manuel Angueyra

    Full Text Available Melanopsin, the receptor molecule that underlies light sensitivity in mammalian 'circadian' receptors, is homologous to invertebrate rhodopsins and has been proposed to operate via a similar signaling pathway. Its downstream effectors, however, remain elusive. Melanopsin also expresses in two distinct light-sensitive cell types in the neural tube of amphioxus. This organism is the most basal extant chordate and can help outline the evolutionary history of different photoreceptor lineages and their transduction mechanisms; moreover, isolated amphioxus photoreceptors offer unique advantages, because they are unambiguously identifiable and amenable to single-cell physiological assays. In the present study whole-cell patch clamp recording, pharmacological manipulations, and immunodetection were utilized to investigate light transduction in amphioxus photoreceptors. A G(q was identified and selectively localized to the photosensitive microvillar membrane, while the pivotal role of phospholipase C was established pharmacologically. The photocurrent was profoundly depressed by IP₃ receptor antagonists, highlighting the importance of IP₃ receptors in light signaling. By contrast, surrogates of diacylglycerol (DAG, as well as poly-unsaturated fatty acids failed to activate a membrane conductance or to alter the light response. The results strengthen the notion that calcium released from the ER via IP₃-sensitive channels may fulfill a key role in conveying--directly or indirectly--the melanopsin-initiated light signal to the photoconductance; moreover, they challenge the dogma that microvillar photoreceptors and phoshoinositide-based light transduction are a prerogative of invertebrate eyes.

  19. Rod photoreceptors express GPR55 in the adult vervet monkey retina

    Bouskila, Joseph; Javadi, Pasha; Casanova, Christian

    2013-01-01

    . Yet, its formal classification is still a matter of debate. CB1R and CB2R expression patterns are well described for rodent and monkey retinas. In the monkey retina, CB1R has been localized in its neural (cone photoreceptor, horizontal, bipolar, amacrine and ganglion cells) and CB2R in glial...

  20. Temperature Dependence of Receptor Potential and Noise in Fly (Calliphora erythrocephala) Photoreceptor Cells

    Roebroek, J.G.H.; Tjonger, M. van; Stavenga, D.G.

    1990-01-01

    We investigated the effect of temperature on the response to light of photoreceptors of the blowfly Calliphora erythrocephala. The latency and the time-to-peak of the responses become shorter as the temperature increases; Q10 = 2.8 ± 0.6. The response amplitude is independent of the temperature in

  1. Moderate Light-Induced Degeneration of Rod Photoreceptors with Delayed Transducin Translocation in shaker1 Mice

    Zallocchi, Marisa; Wang, Wei-Min; Delimont, Duane; Cosgrove, Dominic

    2011-01-01

    Purpose. Usher syndrome is characterized by congenital deafness associated with retinitis pigmentosa (RP). Mutations in the myosin VIIa gene (MYO7A) cause a common and severe subtype of Usher syndrome (USH1B). Shaker1 mice have mutant MYO7A. They are deaf and have vestibular dysfunction but do not develop photoreceptor degeneration. The goal of this study was to investigate abnormalities of photoreceptors in shaker1 mice. Methods. Immunocytochemistry and hydroethidine-based detection of intracellular superoxide production were used. Photoreceptor cell densities under various conditions of light/dark exposures were evaluated. Results. In shaker1 mice, the rod transducin translocation is delayed because of a shift of its light activation threshold to a higher level. Even moderate light exposure can induce oxidative damage and significant rod degeneration in shaker1 mice. Shaker1 mice reared under a moderate light/dark cycle develop severe retinal degeneration in less than 6 months. Conclusions. These findings show that, contrary to earlier studies, shaker1 mice possess a robust retinal phenotype that may link to defective rod protein translocation. Importantly, USH1B animal models are likely vulnerable to light-induced photoreceptor damage, even under moderate light. PMID:21447681

  2. Effective delivery of recombinant proteins to rod photoreceptors via lipid nanovesicles

    Asteriti, Sabrina [Dept. of Translational Research, University of Pisa, Pisa (Italy); Dal Cortivo, Giuditta [Dept. of Life Sciences and Reproduction, University of Verona, Strada Le Grazie 8, Verona (Italy); Pontelli, Valeria [Dept. of Neurological and Movement Sciences, University of Verona, Strada Le Grazie 8, Verona (Italy); Cangiano, Lorenzo [Dept. of Translational Research, University of Pisa, Pisa (Italy); Buffelli, Mario, E-mail: mario.buffelli@univr.it [Dept. of Neurological and Movement Sciences, University of Verona, Strada Le Grazie 8, Verona (Italy); Center for Biomedical Computing, University of Verona, Strada le Grazie 8, 37134 Verona (Italy); Dell’Orco, Daniele, E-mail: daniele.dellorco@univr.it [Dept. of Life Sciences and Reproduction, University of Verona, Strada Le Grazie 8, Verona (Italy); Center for Biomedical Computing, University of Verona, Strada le Grazie 8, 37134 Verona (Italy)

    2015-06-12

    The potential of liposomes to deliver functional proteins in retinal photoreceptors and modulate their physiological response was investigated by two experimental approaches. First, we treated isolated mouse retinas with liposomes encapsulating either recoverin, an important endogenous protein operating in visual phototransduction, or antibodies against recoverin. We then intravitrally injected in vivo liposomes encapsulating either rhodamin B or recoverin and we investigated the distribution in retina sections by confocal microscopy. The content of liposomes was found to be released in higher amount in the photoreceptor layer than in the other regions of the retina and the functional effects of the release were in line with the current model of phototransduction. Our study sets the basis for quantitative investigations aimed at assessing the potential of intraocular protein delivery via biocompatible nanovesicles, with promising implications for the treatment of retinal diseases affecting the photoreceptor layer. - Highlights: • Recombinant proteins encapsulated in nano-sized liposomes injected intravitreally reach retinal photoreceptors. • The phototransduction cascade in rods is modulated by the liposome content. • Mathematical modeling predicts the alteration of the photoresponses following liposome fusion.

  3. Subretinally transplanted embryonic stem cells rescue photoreceptor cells from degeneration in the RCS rats.

    Schraermeyer, U; Thumann, G; Luther, T; Kociok, N; Armhold, S; Kruttwig, K; Andressen, C; Addicks, K; Bartz-Schmidt, K U

    2001-01-01

    The Royal College of Surgeons (RCS) rat is an animal model for retinal degeneration such as the age-related macular degeneration. The RCS rat undergoes a progressive retinal degeneration during the early postnatal period. A potential treatment to prevent this retinal degeneration is the transplantation into the subretinal space of cells that would replace functions of the degenerating retinal pigment epithelium (RPE) cells or may form neurotrophic factors. In this study we have investigated the potential of subretinally transplanted embryonic stem cells to prevent the genetically determined photoreceptor cell degeneration in the RCS rat. Embryonic stem cells from the inner cell mass of the mouse blastocyst were allowed to differentiate to neural precursor cells in vitro and were then transplanted into the subretinal space of 20-day-old RCS rats. Transplanted and sham-operated rats were sacrificed 2 months following cell transplantation. The eyes were enucleated and photoreceptor degeneration was quantified by analyzing and determining the thickness of the outer nuclear layer by light and electron microscopy. In the eyes transplanted with embryonic cells up to 8 rows of photoreceptor cell nuclei were observed, whereas in nontreated control eyes the outer nuclear layer had degenerated completely. Transplantation of embryonic stem cells appears to delay photoreceptor cell degeneration in RCS rats.

  4. Is the photoactive yellow protein a UV-B/blue light photoreceptor?

    Carroll, E. C.; Hospes, M.; Valladares, C.; Hellingwerf, K.J.; Larsen, D.S.

    2011-01-01

    UV light below 300 nm is shown to generate the first photocycle intermediate in the blue light photoreceptor Photoactive Yellow Protein. Fluorescence and ultrafast transient absorption measurements indicate two excitation pathways: UV-B absorption by the chromophore and Fluorescence Resonant Energy

  5. The genetics of some planthormones and photoreceptors in Arabidopsis thaliana (L.) Heynh.

    Koornneef, M.

    1982-01-01

    This thesis describes the isolation and characterization in Arabidopsis thaliana (L.) Heynh. of induced mutants, deficient for gibberellins (GA's), abscisic acid (ABA) and photoreceptors.

    These compounds are known to regulate various facets of plant growth and

  6. Hypoxic preconditioning protects photoreceptors against light damage independently of hypoxia inducible transcription factors in rods.

    Kast, Brigitte; Schori, Christian; Grimm, Christian

    2016-05-01

    Hypoxic preconditioning protects photoreceptors against light-induced degeneration preserving retinal morphology and function. Although hypoxia inducible transcription factors 1 and 2 (HIF1, HIF2) are the main regulators of the hypoxic response, photoreceptor protection does not depend on HIF1 in rods. Here we used rod-specific Hif2a single and Hif1a;Hif2a double knockout mice to investigate the potential involvement of HIF2 in rods for protection after hypoxic preconditioning. To identify potential HIF2 target genes in rods we determined the retinal transcriptome of hypoxic control and rod-specific Hif2a knockouts by RNA sequencing. We show that rods do not need HIF2 for hypoxia-induced increased survival after light exposure. The transcriptomic analysis revealed a number of genes that are potentially regulated by HIF2 in rods; among those were Htra1, Timp3 and Hmox1, candidates that are interesting due to their connection to human degenerative diseases of the retina. We conclude that neither HIF1 nor HIF2 are required in photoreceptors for protection by hypoxic preconditioning. We hypothesize that HIF transcription factors may be needed in other cells to produce protective factors acting in a paracrine fashion on photoreceptor cells. Alternatively, hypoxic preconditioning induces a rod-intrinsic response that is independent of HIF transcription factors. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Chemical Excitation and Inactivation in Photoreceptors of the Fly Mutants trp and nss

    Suss, E.; Barash, S.; Stavenga, D.G.; Stieve, H.; Selinger, Z.; Minke, B.

    1989-01-01

    The Drosophila and Lucilia photoreceptor mutants, trp and nss, respond like wild-type flies to a short pulse of intense light or prolonged dim light; however, upon continuous intense illumination, the trp and nss mutants are unable to maintain persistent excitation. This defect manifests itself by a

  8. Characterization of photoreceptor cell types in the little brown bat Myotis lucifugus (Vespertilionidae).

    Feller, K D; Lagerholm, S; Clubwala, R; Silver, M T; Haughey, D; Ryan, J M; Loew, E R; Deutschlander, M E; Kenyon, K L

    2009-12-01

    We report the expression of three visual opsins in the retina of the little brown bat (Myotis lucifugus, Vespertilionidae). Gene sequences for a rod-specific opsin and two cone-specific opsins were cloned from cDNA derived from bat eyes. Comparative sequence analyses indicate that the two cone opsins correspond to an ultraviolet short-wavelength opsin (SWS1) and a long-wavelength opsin (LWS). Immunocytochemistry using antisera to visual opsins revealed that the little brown bat retina contains two types of cone photoreceptors within a rod-dominated background. However, unlike other mammalian photoreceptors, M. lucifugus cones and rods are morphologically indistinguishable by light microscopy. Both photoreceptor types have a thin, elongated outer segment. Using microspectrophotometry we classified the absorption spectrum for the ubiquitous rods. Similar to other mammals, bat rhodopsin has an absorption peak near 500 nm. Although we were unable to confirm a spectral range, cellular and molecular analyses indicate that M. lucifugus expresses two types of cone visual pigments located within the photoreceptor layer. This study provides important insights into the visual capacity of a nocturnal microchiropteran species.

  9. Photoreceptor spectral sensitivities of the Small White butterfly Pieris rapae crucivora interpreted with optical modeling

    Stavenga, Doekele G.; Arikawa, Kentaro

    The compound eye of the Small White butterfly, Pieris rapae crucivora, has four classes of visual pigments, with peak absorption in the ultraviolet, violet, blue and green, but electrophysiological recordings yielded eight photoreceptors classes: an ultraviolet, violet, blue, double-peaked blue,

  10. Sexual dimorphism of short-wavelength photoreceptors in the small white butterfly, Pieris rapae crucivora

    Arikawa, K; Wakakuwa, M; Qiu, XD; Kurasawa, M; Stavenga, DG; Qiu, Xudong

    2005-01-01

    The eyes of the female small white butterfly, Pieris rapae crucivora, are furnished with three classes of short-wavelength photoreceptors, with sensitivity peaks in the ultraviolet (UV) (lambda(max) = 360 nm), violet (V) (lambda max = 425 nm), and blue (B) (lambda(max) = 453 nm) wavelength range.

  11. Xbp1-Independent Ire1 Signaling Is Required for Photoreceptor Differentiation and Rhabdomere Morphogenesis in Drosophila

    Dina S. Coelho

    2013-11-01

    Full Text Available The unfolded protein response (UPR is composed by homeostatic signaling pathways that are activated by excessive protein misfolding in the endoplasmic reticulum. Ire1 signaling is an important mediator of the UPR, leading to the activation of the transcription factor Xbp1. Here, we show that Drosophila Ire1 mutant photoreceptors have defects in the delivery of rhodopsin-1 to the rhabdomere and in the secretion of Spacemaker/Eyes Shut into the interrhabdomeral space. However, these defects are not observed in Xbp1 mutant photoreceptors. Ire1 mutant retinas have higher mRNA levels for targets of regulated Ire1-dependent decay (RIDD, including for the fatty acid transport protein (fatp. Importantly, the downregulation of fatp by RNAi rescues the rhodopsin-1 delivery defects observed in Ire1 mutant photoreceptors. Our results show that the role of Ire1 during photoreceptor differentiation is independent of Xbp1 function and demonstrate the physiological relevance of the RIDD mechanism in this specific paradigm.

  12. Current status of multiple antigen-presenting peptide vaccine systems: Application of organic and inorganic nanoparticles

    Taguchi Hiroaki

    2011-08-01

    Full Text Available Abstract Many studies are currently investigating the development of safe and effective vaccines to prevent various infectious diseases. Multiple antigen-presenting peptide vaccine systems have been developed to avoid the adverse effects associated with conventional vaccines (i.e., live-attenuated, killed or inactivated pathogens, carrier proteins and cytotoxic adjuvants. Recently, two main approaches have been used to develop multiple antigen-presenting peptide vaccine systems: (1 the addition of functional components, e.g., T-cell epitopes, cell-penetrating peptides, and lipophilic moieties; and (2 synthetic approaches using size-defined nanomaterials, e.g., self-assembling peptides, non-peptidic dendrimers, and gold nanoparticles, as antigen-displaying platforms. This review summarizes the recent experimental studies directed to the development of multiple antigen-presenting peptide vaccine systems.

  13. Multiple criteria decision making for sustainable energy and transportation systems. Proceedings

    Ehrgott, Matthias [Auckland Univ. (New Zealand). Dept. of Engineering Science; Naujoks, Boris [Login GmbH, Schwelm (Germany).; Stewart, Theodor J. [Cape Town Univ., Rondebosch (South Africa). Dept. of Statistical Sciences; Wallenius, Jyrki (eds.) [Helsinki School of Economics (Finland). Dept. of Business Technology

    2010-07-01

    In the twenty-first century the sustainability of energy and transportation systems is on the top of the political agenda in many countries around the world and governments are establishing policies towards a sustainable, low emissions energy future. Environmental impacts of human economic activity necessitate the consideration of conflicting goals in decision making processes to develop sustainable systems. Any sustainable development has to reconcile conflicting economic and environmental objectives and criteria. The science of multiple criteria decision making has a lot to offer in addressing this need. Decision making with multiple (conflicting) criteria is the topic of research that is at the heart of the International Society of Multiple Criteria Decision Making. This book is based on selected papers presented at the societies 19th International Conference, held at The University of Auckland, New Zealand, from 7th to 12th January 2008 under the theme ''MCDM for Sustainable Energy and Transportation Systems''. (orig.)

  14. A Two-Level Task Scheduler on Multiple DSP System for OpenCL

    Li Tian

    2014-04-01

    Full Text Available This paper addresses the problem that multiple DSP system does not support OpenCL programming. With the compiler, runtime, and the kernel scheduler proposed, an OpenCL application becomes portable not only between multiple CPU and GPU, but also between embedded multiple DSP systems. Firstly, the LLVM compiler was imported for source-to-source translation in which the translated source was supported by CCS. Secondly, two-level schedulers were proposed to support efficient OpenCL kernel execution. The DSP/BIOS is used to schedule system level tasks such as interrupts and drivers; however, the synchronization mechanism resulted in heavy overhead during task switching. So we designed an efficient second level scheduler especially for OpenCL kernel work-item scheduling. The context switch process utilizes the 8 functional units and cross path links which was superior to DSP/BIOS in the aspect of task switching. Finally, dynamic loading and software managed CACHE were redesigned for OpenCL running on multiple DSP system. We evaluated the performance using some common OpenCL kernels from NVIDIA, AMD, NAS, and Parboil benchmarks. Experimental results show that the DSP OpenCL can efficiently exploit the computing resource of multiple cores.

  15. Error Analysis and Calibration Method of a Multiple Field-of-View Navigation System

    Shi, Shuai; Zhao, Kaichun; You, Zheng; Ouyang, Chenguang; Cao, Yongkui; Wang, Zhenzhou

    2017-01-01

    The Multiple Field-of-view Navigation System (MFNS) is a spacecraft subsystem built to realize the autonomous navigation of the Spacecraft Inside Tiangong Space Station. This paper introduces the basics of the MFNS, including its architecture, mathematical model and analysis, and numerical simulation of system errors. According to the performance requirement of the MFNS, the calibration of both intrinsic and extrinsic parameters of the system is assumed to be essential and pivotal. Hence, a n...

  16. Multiple perspectives approach as a framework to analyse social systems in a developing country context

    Turpin, M

    2009-03-01

    Full Text Available synthesis. Keywords: multiple perspectives, unbounded systems thinking, information systems theory, group support systems, decision support, developing countries. Acknowledgements: The authors wish to acknowledge the CSIR Strategic Research Programme..., in which chaos and disorder do not reign or take a foot hold” (Mc Alister 2008:10) and contrast these beautiful ideals with the “horrible situation” (Kriek 2008:13) of the xenophobic violence and “non-aesthetic elements like the informal settlements...

  17. Multiple Flow Loop SCADA System Implemented on the Production Prototype Loop

    Baily, Scott A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dalmas, Dale Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wheat, Robert Mitchell [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Woloshun, Keith Albert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dale, Gregory E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-16

    The following report covers FY 15 activities to develop supervisory control and data acquisition (SCADA) system for the Northstar Moly99 production prototype gas flow loop. The goal of this effort is to expand the existing system to include a second flow loop with a larger production-sized blower. Besides testing the larger blower, this system will demonstrate the scalability of our solution to multiple flow loops.

  18. A non-inheritable maternal Cas9-based multiple-gene editing system in mice

    Takayuki Sakurai; Akiko Kamiyoshi; Hisaka Kawate; Chie Mori; Satoshi Watanabe; Megumu Tanaka; Ryuichi Uetake; Masahiro Sato; Takayuki Shindo

    2016-01-01

    The CRISPR/Cas9 system is capable of editing multiple genes through one-step zygote injection. The preexisting method is largely based on the co-injection of Cas9 DNA (or mRNA) and guide RNAs (gRNAs); however, it is unclear how many genes can be simultaneously edited by this method, and a reliable means to generate transgenic (Tg) animals with multiple gene editing has yet to be developed. Here, we employed non-inheritable maternal Cas9 (maCas9) protein derived from Tg mice with systemic Cas9...

  19. Cryptanalysis of the public key encryption based on multiple chaotic systems

    Zhang Linhua

    2008-01-01

    Recently, Ranjan proposed a novel public key encryption technique based on multiple chaotic systems [Phys Lett 2005;95]. Unfortunately, Wang soon gave a successful attack on its special case based on Parseval's theorem [Wang K, Pei W, Zhou L, et al. Security of public key encryption technique based on multiple chaotic system. Phys Lett A, in press]. In this letter, we give an improved example which can avoid the attack and point out that Wang cannot find the essential drawback of the technique. However, further experimental result shows Ruanjan's encryption technique is inefficient, and detailed theoretic analysis shows that the complexity to break the cryptosystem is overestimated

  20. Comparison of Multiple-Microphone and Single-Loudspeaker Adaptive Feedback/Echo Cancellation Systems

    Guo, Meng; Elmedyb, Thomas Bo; Jensen, Søren Holdt

    2011-01-01

    Recently, we introduced a frequency domain measure - the power transfer function - to predict the convergence rate, system stability bound and the steady-state behavior across time and frequency of a least mean square based feedback/echo cancellation algorithm in a general multiple-microphone and......Recently, we introduced a frequency domain measure - the power transfer function - to predict the convergence rate, system stability bound and the steady-state behavior across time and frequency of a least mean square based feedback/echo cancellation algorithm in a general multiple...

  1. Channel Estimation and Optimal Power Allocation for a Multiple-Antenna OFDM System

    Yao Kung

    2002-01-01

    Full Text Available We propose combining channel estimation and optimal power allocation approaches for a multiple-antenna orthogonal frequency division multiplexing (OFDM system in high-speed transmission applications. We develop a least-square channel estimation approach, derive the performance bound of the estimator, and investigate the optimal training sequences for initial channel acquisition. Based on the channel estimates, the optimal power allocation solution which maximizes the bandwidth efficiency is derived under power and quality of service (Qos (symbol error rate constraints. It is shown that combining channel tracking and adaptive power allocation can dramatically enhance the outage capacity of an OFDM multiple-antenna system when severing fading occurs.

  2. Multiple star systems observed with CoRoT and Kepler

    Southworth John

    2015-01-01

    Full Text Available The CoRoT and Kepler satellites were the first space platforms designed to perform high-precision photometry for a large number of stars. Multiple systems display a wide variety of photometric variability, making them natural benefactors of these missions. I review the work arising from CoRoT and Kepler observations of multiple systems, with particular emphasis on eclipsing binaries containing giant stars, pulsators, triple eclipses and/or low-mass stars. Many more results remain untapped in the data archives of these missions, and the future holds the promise of K2, TESS and PLATO.

  3. Human amniotic fluid promotes retinal pigmented epithelial cells' trans-differentiation into rod photoreceptors and retinal ganglion cells.

    Ghaderi, Shima; Soheili, Zahra-Soheila; Ahmadieh, Hamid; Davari, Maliheh; Jahromi, Fatemeh Sanie; Samie, Shahram; Rezaie-Kanavi, Mozhgan; Pakravesh, Jalil; Deezagi, Abdolkhalegh

    2011-09-01

    To evaluate the effect of human amniotic fluid (HAF) on retinal pigmented epithelial cells growth and trans-differentiation into retinal neurons, retinal pigmented epithelium (RPE) cells were isolated from neonatal human cadaver eye globes and cultured in Dulbecco's modified Eagle's medium-F12 supplemented with 10% fetal bovine serum (FBS). Confluent monolayer cultures were trypsinized and passaged using FBS-containing or HAF-containing media. Amniotic fluid samples were received from pregnant women in the first trimester of gestation. Cell proliferation and death enzyme-linked immunosorbent assays were performed to assess the effect of HAF on RPE cell growth. Trans-differentiation into rod photoreceptors and retinal ganglion cells was also studied using immunocytochemistry and real-time polymerase chain reaction techniques. Primary cultures of RPE cells were successfully established under FBS-containing or HAF-containing media leading to rapid cell growth and proliferation. When RPE cells were moved to in vitro culture system, they began to lose their differentiation markers such as pigmentation and RPE65 marker and trans-differentiated neural-like cells followed by spheroid colonies pertaining to stem/progenitor cells were morphologically detected. Immunocytochemistry (ICC) analysis of HAF-treated cultures showed a considerable expression of Rhodopsin gene (30% Rhodopsin-positive cells) indicating trans-differentiation of RPE cells to rod photoreceptors. Real-time polymerase chain reaction revealed an HAF-dose-dependant expression of Thy-1 gene (RGC marker) and significant promoting effect of HAF on RGCs generation. The data presented here suggest that HAF possesses invaluable stimulatory effect on RPE cells growth and trans-differentiation into retinal neurons. It can be regarded as a newly introduced enriched supplement in serum-free kinds of media used in neuro-retinal regeneration studies.

  4. 'Chronic cerebrospinal venous insufficiency' in multiple sclerosis. Is multiple sclerosis a disease of the cerebrospinal venous outflow system?

    Wattjes, M.P.; Doepp, F.; Bendszus, M.; Fiehler, J.

    2011-01-01

    Chronic impaired venous outflow from the central nervous system has recently been claimed to be associated with multiple sclerosis (MS) pathology. This resulted in the term chronic cerebrospinal venous insufficiency (CCSVI) in MS. The concept of CCSVI is based on sonography studies showing that impaired venous outflow leading to pathological reflux is almost exclusively present in MS patients but not in healthy controls. Based on these findings, a new pathophysiological concept has been introduced suggesting that chronic venous outflow obstruction and venous reflux in the CNS result in pathological iron depositions leading to inflammation and neurodegeneration. The theory of CCSVI in MS has rapidly generated tremendous interest in the media and among patients and the scientific community. In particular, the potential shift in treatment concepts possibly leading to an interventional treatment approach including balloon angioplasty and venous stent placement is currently being debated. However, results from recent studies involving several imaging modalities have raised substantial concerns regarding the CCSVI concept in MS. In this review article, we explain the concept of CCSVI in MS and discuss this hypothesis in the context of MS pathophysiology and imaging studies which have tried to reproduce or refute this theory. In addition, we draw some major conclusions focusing in particular on the crucial question as to whether interventional treatment options are expedient. In conclusion, the present conclusive data confuting the theory of CCSVI in MS should lead to reluctance with respect to the interventional treatment of possible venous anomalies in MS patients. (orig.)

  5. Unidirectional photoreceptor-to-Müller glia coupling and unique K+ channel expression in Caiman retina.

    Astrid Zayas-Santiago

    Full Text Available Müller cells, the principal glial cells of the vertebrate retina, are fundamental for the maintenance and function of neuronal cells. In most vertebrates, including humans, Müller cells abundantly express Kir4.1 inwardly rectifying potassium channels responsible for hyperpolarized membrane potential and for various vital functions such as potassium buffering and glutamate clearance; inter-species differences in Kir4.1 expression were, however, observed. Localization and function of potassium channels in Müller cells from the retina of crocodiles remain, hitherto, unknown.We studied retinae of the Spectacled caiman (Caiman crocodilus fuscus, endowed with both diurnal and nocturnal vision, by (i immunohistochemistry, (ii whole-cell voltage-clamp, and (iii fluorescent dye tracing to investigate K+ channel distribution and glia-to-neuron communications.Immunohistochemistry revealed that caiman Müller cells, similarly to other vertebrates, express vimentin, GFAP, S100β, and glutamine synthetase. In contrast, Kir4.1 channel protein was not found in Müller cells but was localized in photoreceptor cells. Instead, 2P-domain TASK-1 channels were expressed in Müller cells. Electrophysiological properties of enzymatically dissociated Müller cells without photoreceptors and isolated Müller cells with adhering photoreceptors were significantly different. This suggests ion coupling between Müller cells and photoreceptors in the caiman retina. Sulforhodamine-B injected into cones permeated to adhering Müller cells thus revealing a uni-directional dye coupling.Our data indicate that caiman Müller glial cells are unique among vertebrates studied so far by predominantly expressing TASK-1 rather than Kir4.1 K+ channels and by bi-directional ion and uni-directional dye coupling to photoreceptor cells. This coupling may play an important role in specific glia-neuron signaling pathways and in a new type of K+ buffering.

  6. Adaptive optics fundus images of cone photoreceptors in the macula of patients with retinitis pigmentosa.

    Tojo, Naoki; Nakamura, Tomoko; Fuchizawa, Chiharu; Oiwake, Toshihiko; Hayashi, Atsushi

    2013-01-01

    The purpose of this study was to examine cone photoreceptors in the macula of patients with retinitis pigmentosa using an adaptive optics fundus camera and to investigate any correlations between cone photoreceptor density and findings on optical coherence tomography and fundus autofluorescence. We examined two patients with typical retinitis pigmentosa who underwent ophthalmological examination, including measurement of visual acuity, and gathering of electroretinographic, optical coherence tomographic, fundus autofluorescent, and adaptive optics fundus images. The cone photoreceptors in the adaptive optics images of the two patients with retinitis pigmentosa and five healthy subjects were analyzed. An abnormal parafoveal ring of high-density fundus autofluorescence was observed in the macula in both patients. The border of the ring corresponded to the border of the external limiting membrane and the inner segment and outer segment line in the optical coherence tomographic images. Cone photoreceptors at the abnormal parafoveal ring were blurred and decreased in the adaptive optics images. The blurred area corresponded to the abnormal parafoveal ring in the fundus autofluorescence images. Cone densities were low at the blurred areas and at the nasal and temporal retina along a line from the fovea compared with those of healthy controls. The results for cone spacing and Voronoi domains in the macula corresponded with those for the cone densities. Cone densities were heavily decreased in the macula, especially at the parafoveal ring on high-density fundus autofluorescence in both patients with retinitis pigmentosa. Adaptive optics images enabled us to observe in vivo changes in the cone photoreceptors of patients with retinitis pigmentosa, which corresponded to changes in the optical coherence tomographic and fundus autofluorescence images.

  7. Transcriptional regulation of rod photoreceptor homeostasis revealed by in vivo NRL targetome analysis.

    Hong Hao

    Full Text Available A stringent control of homeostasis is critical for functional maintenance and survival of neurons. In the mammalian retina, the basic motif leucine zipper transcription factor NRL determines rod versus cone photoreceptor cell fate and activates the expression of many rod-specific genes. Here, we report an integrated analysis of NRL-centered gene regulatory network by coupling chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-Seq data from Illumina and ABI platforms with global expression profiling and in vivo knockdown studies. We identified approximately 300 direct NRL target genes. Of these, 22 NRL targets are associated with human retinal dystrophies, whereas 95 mapped to regions of as yet uncloned retinal disease loci. In silico analysis of NRL ChIP-Seq peak sequences revealed an enrichment of distinct sets of transcription factor binding sites. Specifically, we discovered that genes involved in photoreceptor function include binding sites for both NRL and homeodomain protein CRX. Evaluation of 26 ChIP-Seq regions validated their enhancer functions in reporter assays. In vivo knockdown of 16 NRL target genes resulted in death or abnormal morphology of rod photoreceptors, suggesting their importance in maintaining retinal function. We also identified histone demethylase Kdm5b as a novel secondary node in NRL transcriptional hierarchy. Exon array analysis of flow-sorted photoreceptors in which Kdm5b was knocked down by shRNA indicated its role in regulating rod-expressed genes. Our studies identify candidate genes for retinal dystrophies, define cis-regulatory module(s for photoreceptor-expressed genes and provide a framework for decoding transcriptional regulatory networks that dictate rod homeostasis.

  8. Retinal cone photoreceptors of the deer mouse Peromyscus maniculatus: development, topography, opsin expression and spectral tuning.

    Patrick Arbogast

    Full Text Available A quantitative analysis of photoreceptor properties was performed in the retina of the nocturnal deer mouse, Peromyscus maniculatus, using pigmented (wildtype and albino animals. The aim was to establish whether the deer mouse is a more suitable model species than the house mouse for photoreceptor studies, and whether oculocutaneous albinism affects its photoreceptor properties. In retinal flatmounts, cone photoreceptors were identified by opsin immunostaining, and their numbers, spectral types, and distributions across the retina were determined. Rod photoreceptors were counted using differential interference contrast microscopy. Pigmented P. maniculatus have a rod-dominated retina with rod densities of about 450.000/mm(2 and cone densities of 3000-6500/mm(2. Two cone opsins, shortwave sensitive (S and middle-to-longwave sensitive (M, are present and expressed in distinct cone types. Partial sequencing of the S opsin gene strongly supports UV sensitivity of the S cone visual pigment. The S cones constitute a 5-15% minority of the cones. Different from house mouse, S and M cone distributions do not have dorsoventral gradients, and coexpression of both opsins in single cones is exceptional (<2% of the cones. In albino P. maniculatus, rod densities are reduced by approximately 40% (270.000/mm(2. Overall, cone density and the density of cones exclusively expressing S opsin are not significantly different from pigmented P. maniculatus. However, in albino retinas S opsin is coexpressed with M opsin in 60-90% of the cones and therefore the population of cones expressing only M opsin is significantly reduced to 5-25%. In conclusion, deer mouse cone properties largely conform to the general mammalian pattern, hence the deer mouse may be better suited than the house mouse for the study of certain basic cone properties, including the effects of albinism on cone opsin expression.

  9. Gibberellin and auxin influence the diurnal transcription pattern of photoreceptor genes via CRY1a in tomato.

    Paolo Facella

    Full Text Available Plant photoreceptors, phytochromes and cryptochromes, regulate many aspects of development and growth, such as seed germination, stem elongation, seedling de-etiolation, cotyledon opening, flower induction and circadian rhythms. There are several pieces of evidence of interaction between photoreceptors and phyto-hormones in all of these physiological processes, but little is known about molecular and genetic mechanisms underlying hormone-photoreceptor crosstalk.In this work, we investigated the molecular effects of exogenous phyto-hormones to photoreceptor gene transcripts of tomato wt, as well as transgenic and mutant lines with altered cryptochromes, by monitoring day/night transcript oscillations. GA and auxin alter the diurnal expression level of different photoreceptor genes in tomato, especially in mutants that lack a working form of cryptochrome 1a: in those mutants the expression of some (IAA or most (GA photoreceptor genes is down regulated by these hormones.Our results highlight the presence of molecular relationships among cryptochrome 1a protein, hormones, and photoreceptors' gene expression in tomato, suggesting that manipulation of cryptochromes could represent a good strategy to understand in greater depth the role of phyto-hormones in the plant photoperceptive mechanism.

  10. Multiple single-board-computer system for the KEK positron generator control

    Nakahara, Kazuo; Abe, Isamu; Enomoto, Atsushi; Otake, Yuji; Urano, Takao

    1986-01-01

    The KEK positron generator is controlled by means of a distributed microprocessor network. The control system is composed of three kinds of equipment: device controllers for the linac equipment, operation management stations and a communication network. Individual linac equipment has its own microprocessor-based controller. A multiple single board computer (SBC) system is used for communication control and for equipment surveillance; it has a database containing communication and linac equipment status information. The linac operation management that should be the most soft part in the control system, is separated from the multiple SBC system and is carried out by work-stations. The principle that every processor executes only one task is maintained throughout the control system. This made the software architecture very simple. (orig.)

  11. Advanced topics in control and estimation of state-multiplicative noisy systems

    Gershon, Eli

    2013-01-01

    Advanced Topics in Control and Estimation of State-Multiplicative Noisy Systems begins with an introduction and extensive literature survey. The text proceeds to cover solutions of measurement-feedback control and state problems and the formulation of the Bounded Real Lemma for both continuous- and discrete-time systems. The continuous-time reduced-order and stochastic-tracking control problems for delayed systems are then treated. Ideas of nonlinear stability are introduced for infinite-horizon systems, again, in both the continuous- and discrete-time cases. The reader is introduced to six practical examples of noisy state-multiplicative control and filtering associated with various fields of control engineering. The book is rounded out by a three-part appendix containing stochastic tools necessary for a proper appreciation of the text: a basic introduction to nonlinear stochastic differential equations and aspects of switched systems and peak to peak  optimal control and filtering. Advanced Topics in Contr...

  12. Adaptive modified function projective synchronization of multiple time-delayed chaotic Rossler system

    Sudheer, K. Sebastian; Sabir, M.

    2011-01-01

    In this Letter we consider modified function projective synchronization of unidirectionally coupled multiple time-delayed Rossler chaotic systems using adaptive controls. Recently, delay differential equations have attracted much attention in the field of nonlinear dynamics. The high complexity of the multiple time-delayed systems can provide a new architecture for enhancing message security in chaos based encryption systems. Adaptive control can be used for synchronization when the parameters of the system are unknown. Based on Lyapunov stability theory, the adaptive control law and the parameter update law are derived to make the state of two chaotic systems are function projective synchronized. Numerical simulations are presented to demonstrate the effectiveness of the proposed adaptive controllers.

  13. Application of the 2012 revised diagnostic definitions for paediatric multiple sclerosis and immune-mediated central nervous system demyelination disorders

    van Pelt, E. Danielle; Neuteboom, Rinze F.; Ketelslegers, Immy A.; Boon, Maartje; Catsman-Berrevoets, Coriene E.; Hintzen, Rogier Q.

    Background Recently, the International Paediatric Multiple Sclerosis Study Group (IPMSSG) definitions for the diagnosis of immune-mediated acquired demyelinating syndromes (ADS) of the central nervous system, including paediatric multiple sclerosis (MS), have been revised. Objective To evaluate the

  14. High security chaotic multiple access scheme for visible light communication systems with advanced encryption standard interleaving

    Qiu, Junchao; Zhang, Lin; Li, Diyang; Liu, Xingcheng

    2016-06-01

    Chaotic sequences can be applied to realize multiple user access and improve the system security for a visible light communication (VLC) system. However, since the map patterns of chaotic sequences are usually well known, eavesdroppers can possibly derive the key parameters of chaotic sequences and subsequently retrieve the information. We design an advanced encryption standard (AES) interleaving aided multiple user access scheme to enhance the security of a chaotic code division multiple access-based visible light communication (C-CDMA-VLC) system. We propose to spread the information with chaotic sequences, and then the spread information is interleaved by an AES algorithm and transmitted over VLC channels. Since the computation complexity of performing inverse operations to deinterleave the information is high, the eavesdroppers in a high speed VLC system cannot retrieve the information in real time; thus, the system security will be enhanced. Moreover, we build a mathematical model for the AES-aided VLC system and derive the theoretical information leakage to analyze the system security. The simulations are performed over VLC channels, and the results demonstrate the effectiveness and high security of our presented AES interleaving aided chaotic CDMA-VLC system.

  15. Hybrid Control System for Greater Resilience Using Multiple Isolation and Building Connection

    Masaki Taniguchi

    2016-10-01

    Full Text Available An innovative hybrid control building system of multiple isolation and connection is proposed and investigated using both time-history and input energy responses for various types of ground motions together with transfer functions. It is concerned that the seismic displacement response at the base-isolation layer of the existing base-isolated buildings may extremely increase under long-period and long-duration ground motions which are getting great attention recently. In order to enhance the seismic performance of those base-isolated buildings, a novel hybrid system of multiple isolation and building-connection is proposed and compared with other structural systems such as an independent multiple isolation system, a hybrid system of base-isolation and building-connection. Furthermore, the robustness of seismic responses of the proposed hybrid system for various types of ground motion is discussed through the comparison of various structural systems including non-hybrid systems. Finally the optimal connection damper location is investigated using a sensitivity-type optimization approach.

  16. Multiple Access Interference Reduction Using Received Response Code Sequence for DS-CDMA UWB System

    Toh, Keat Beng; Tachikawa, Shin'ichi

    This paper proposes a combination of novel Received Response (RR) sequence at the transmitter and a Matched Filter-RAKE (MF-RAKE) combining scheme receiver system for the Direct Sequence-Code Division Multiple Access Ultra Wideband (DS-CDMA UWB) multipath channel model. This paper also demonstrates the effectiveness of the RR sequence in Multiple Access Interference (MAI) reduction for the DS-CDMA UWB system. It suggests that by using conventional binary code sequence such as the M sequence or the Gold sequence, there is a possibility of generating extra MAI in the UWB system. Therefore, it is quite difficult to collect the energy efficiently although the RAKE reception method is applied at the receiver. The main purpose of the proposed system is to overcome the performance degradation for UWB transmission due to the occurrence of MAI during multiple accessing in the DS-CDMA UWB system. The proposed system improves the system performance by improving the RAKE reception performance using the RR sequence which can reduce the MAI effect significantly. Simulation results verify that significant improvement can be obtained by the proposed system in the UWB multipath channel models.

  17. NRC Information No. 88-86: Operating with multiple grounds in direct current distribution systems

    Rossi, C.E.

    1992-01-01

    During recent NRC maintenance inspections at Quad Cities, Oconee, and D.C. Cook power reactor facilities, it was found that plants had been operating with multiple grounds in the dc distribution systems for extended periods. Specific examples are described. Most nuclear power plant dc systems are two-wire ungrounded, combination battery/charger systems equipped with ground detection. Typical ground detection system features include a remote annunciator and a local indicator and/or recorder. Ground detectors are incorporated in the dc system so that if a single ground point does occur, immediate steps can be taken to clear the ground fault from the system. Failure to respond to a single ground will mask subsequent grounds. Multiple grounds can cause the indiscriminate operation of equipment, which may have safety consequences. Grounds can cause control circuit fuses to fail and can render important safety equipment inoperable as previously described. Furthermore, batteries have a designed capacity to supply power during a station blackout condition, and this capacity can be affected by the presence of unanalyzed loads in the form of multiple grounds. It is recognized that troubleshooting and finding grounds on a dc system are difficult tasks that may affect plant operation. The licensees previously mentioned have reviewed their designs and conditions for potential impact on safety system operability and have taken corrective actions to minimize the effect of grounds

  18. In silico modeling of epigenetic-induced changes in photoreceptor cis-regulatory elements.

    Hossain, Reafa A; Dunham, Nicholas R; Enke, Raymond A; Berndsen, Christopher E

    2018-01-01

    DNA methylation is a well-characterized epigenetic repressor of mRNA transcription in many plant and vertebrate systems. However, the mechanism of this repression is not fully understood. The process of transcription is controlled by proteins that regulate recruitment and activity of RNA polymerase by binding to specific cis-regulatory sequences. Cone-rod homeobox (CRX) is a well-characterized mammalian transcription factor that controls photoreceptor cell-specific gene expression. Although much is known about the functions and DNA binding specificity of CRX, little is known about how DNA methylation modulates CRX binding affinity to genomic cis-regulatory elements. We used bisulfite pyrosequencing of human ocular tissues to measure DNA methylation levels of the regulatory regions of RHO , PDE6B, PAX6 , and LINE1 retrotransposon repeats. To describe the molecular mechanism of repression, we used molecular modeling to illustrate the effect of DNA methylation on human RHO regulatory sequences. In this study, we demonstrate an inverse correlation between DNA methylation in regulatory regions adjacent to the human RHO and PDE6B genes and their subsequent transcription in human ocular tissues. Docking of CRX to the DNA models shows that CRX interacts with the grooves of these sequences, suggesting changes in groove structure could regulate binding. Molecular dynamics simulations of the RHO promoter and enhancer regions show changes in the flexibility and groove width upon epigenetic modification. Models also demonstrate changes in the local dynamics of CRX binding sites within RHO regulatory sequences which may account for the repression of CRX-dependent transcription. Collectively, these data demonstrate epigenetic regulation of CRX binding sites in human retinal tissue and provide insight into the mechanism of this mode of epigenetic regulation to be tested in future experiments.

  19. Competing failure analysis in phased-mission systems with multiple functional dependence groups

    Wang, Chaonan; Xing, Liudong; Peng, Rui; Pan, Zhusheng

    2017-01-01

    A phased-mission system (PMS) involves multiple, consecutive, non-overlapping phases of operation. The system structure function and component failure behavior in a PMS can change from phase to phase, posing big challenges to the system reliability analysis. Further complicating the problem is the functional dependence (FDEP) behavior where the failure of certain component(s) causes other component(s) to become unusable or inaccessible or isolated. Previous studies have shown that FDEP can cause competitions between failure propagation and failure isolation in the time domain. While such competing failure effects have been well addressed in single-phase systems, only little work has focused on PMSs with a restrictive assumption that a single FDEP group exists in one phase of the mission. Many practical systems (e.g., computer systems and networks), however may involve multiple FDEP groups during the mission. Moreover, different FDEP groups can be dependent due to sharing some common components; they may appear in a single phase or multiple phases. This paper makes new contributions by modeling and analyzing reliability of PMSs subject to multiple FDEP groups through a Markov chain-based methodology. Propagated failures with both global and selective effects are considered. Four case studies are presented to demonstrate application of the proposed method. - Highlights: • Reliability of phased-mission systems subject to competing failure propagation and isolation effects is modeled. • Multiple independent or dependent functional dependence groups are considered. • Propagated failures with global effects and selective effects are studied. • Four case studies demonstrate generality and application of the proposed Markov-based method.

  20. Performance analysis of multiple interference suppression over asynchronous/synchronous optical code-division multiple-access system based on complementary/prime/shifted coding scheme

    Nieh, Ta-Chun; Yang, Chao-Chin; Huang, Jen-Fa

    2011-08-01

    A complete complementary/prime/shifted prime (CPS) code family for the optical code-division multiple-access (OCDMA) system is proposed. Based on the ability of complete complementary (CC) code, the multiple-access interference (MAI) can be suppressed and eliminated via spectral amplitude coding (SAC) OCDMA system under asynchronous/synchronous transmission. By utilizing the shifted prime (SP) code in the SAC scheme, the hardware implementation of encoder/decoder can be simplified with a reduced number of optical components, such as arrayed waveguide grating (AWG) and fiber Bragg grating (FBG). This system has a superior performance as compared to previous bipolar-bipolar coding OCDMA systems.

  1. [A case of MEWDS. "The multiple evanescent white-dot syndrome"].

    Lefrançois, A; Hamard, H; Corbe, C; Schmitt, A; Badelon, I; Vidal, A

    1989-01-01

    A young white man developed acute bilateral visual loss with no previous general illness. Ophthalmoscopic examination showed multiple small yellow-white lesions scattered throughout the posterior poles and mild periphery fundus. There was also fine granularity of two foveal areas and one optic disc margin was blurred. Fluorescein angiography showed early hyperfluorescence of the lesions and late staining of the retinal pigment epithelium. Electrophysiologic abnormalities were transient, asymmetric, more marked in photopic than in scotopic. The origin could be in retinal bipolar cells. These lesions regressed, with return of normal visual function within several weeks. These clinical findings are different from others acute inflammatory diseases primarily involving retinal pigment epithelium and photoreceptors. This aspect is usually described as "multiple evanescent white dot syndrome". The etiology of this syndrome remains unknown with no evidence of systemic disease. A history of flulike illness is rare.

  2. Multiple myeloma and central nervous system involvement: experience of a Brazilian center.

    Dias, Ana Luiza Miranda Silva; Higashi, Fabiana; Peres, Ana Lúcia M; Cury, Pricilla; Crusoé, Edvan de Queiroz; Hungria, Vânia Tietsche de Moraes

    The estimated involvement of the central nervous system in patients with multiple myeloma is rare at about 1%. The infiltration can be identified at the time multiple myeloma is diagnosed or during its progression. However, it is more common in refractory disease or during relapse. This retrospective cohort study reviewed data from medical records of patients followed up at the Gammopathy Outpatient Clinic of Santa Casa de Misericórdia de São Paulo from January 2008 to December 2016. Twenty patients were included, with a median follow-up of 33.5 months after central nervous system infiltration. The prevalence was 7%. The median age at diagnosis of multiple myeloma was 56.1 years, with 70% of participants being female. Sixteen patients had central nervous system infiltration at diagnosis of multiple myeloma. Seventeen patients had exclusive osteodural lesions and three had infiltrations of the leptomeninge, of which one had exclusive involvement and two had associated osteodural lesions. The median overall survival was 40.3 months after central nervous system involvement. The median overall survival in the group with central nervous system infiltration at relapse was 7.4 months. The patients with leptomeningeal involvement had a median overall survival of 5.8 months. Central nervous system infiltration is a rare condition, but it should be considered as a possibility in patients with multiple myeloma and neurological symptoms. The best treatment regimen for this condition remains unknown and, in most cases, the prognosis is unfavorable. Copyright © 2017. Published by Elsevier Editora Ltda.

  3. Towards a decision support system for control of multiple food safety hazards in raw milk production

    Spiegel, van der M.; Sterrenburg, P.; Haasnoot, W.; Fels-Klerx, van der H.J.

    2013-01-01

    Decision support systems (DSS) for controlling multiple food safety hazards in raw milk production have not yet been developed, but the underlying components are fragmentarily available. This article presents the state-of-the-art of essential DSS elements for judging food safety compliance of raw

  4. Xylohypha bantiana Multiple Brain Abscesses in a Patient with Systemic Lupus Erythematosus

    Khalid F AlHabib

    2003-01-01

    Full Text Available Xylohypha bantiana is a rare cause of cerebral fungal infection (phaeohyphomycosis. We report on a 72-year-old man who, while taking several immunosuppressive medications for systemic lupus erythematosus, presented with multiple bilateral cerebral abscesses caused by X bantiana. The lesions were not surgically amenable and the patient died two months after discontinuing antifungal therapy.

  5. Application of heterogeneous multiple camera system with panoramic capabilities in a harbor environment

    Schwering, P.B.W.; Lensen, H.A.; Broek, S.P. van den; Hollander, R.J.M. den; Mark, W. van der; Bouma, H.; Kemp, R.A.W.

    2009-01-01

    In a harbor environment threats like explosives-packed rubber boats, mine-carrying swimmers and divers must be detected in an early stage. This paper describes the integration and use of a heterogeneous multiple camera system with panoramic observation capabilities for detecting these small vessels

  6. The MORPG-Based Learning System for Multiple Courses: A Case Study on Computer Science Curriculum

    Liu, Kuo-Yu

    2015-01-01

    This study aimed at developing a Multiplayer Online Role Playing Game-based (MORPG) Learning system which enabled instructors to construct a game scenario and manage sharable and reusable learning content for multiple courses. It used the curriculum of "Introduction to Computer Science" as a study case to assess students' learning…

  7. Metallothionein expression in the central nervous system of multiple sclerosis patients

    Penkowa, M; Espejo, C; Ortega-Aznar, A

    2003-01-01

    Multiple sclerosis (MS) is a major chronic demyelinating and inflammatory disease of the central nervous system (CNS) in which oxidative stress likely plays a pathogenic role in the development of myelin and neuronal damage. Metallothioneins (MTs) are antioxidant proteins induced in the CNS...

  8. Multiple periodic solutions for a fourth-order discrete Hamiltonian system

    Yongkun Li

    2010-12-01

    Full Text Available By means of a three critical points theorem proposed by Brezis and Nirenberg and a general version of Mountain Pass Theorem, we obtain some multiplicity results for periodic solutions of a fourth-order discrete Hamiltonian system Δ4u(t-2+∇ F(t,u(t=0 for all t∈ Z.

  9. Inverse chaos synchronization in linearly and nonlinearly coupled systems with multiple time-delays

    Shahverdiev, E.M.; Hashimov, R.H.; Nuriev, R.A.; Hashimova, L.H.; Huseynova, E.M.; Shore, K.A.

    2005-04-01

    We report on inverse chaos synchronization between two unidirectionally linearly and nonlinearly coupled chaotic systems with multiple time-delays and find the existence and stability conditions for different synchronization regimes. We also study the effect of parameter mismatches on synchonization regimes. The method is tested on the famous Ikeda model. Numerical simulations fully support the analytical approach. (author)

  10. BER and total throughput of asynchronous DS-OCDMA/WDM systems with multiple user interference

    Ghiringhelli, F.; Zervas, M.N.

    2003-01-01

    The BER and throughput of Direct-Sequence OCDMA/WDM systems based on quadripolar codes and superstructured fiber Bragg gratings are statistically derived under asynchronous operation, intensity detection, and Multiple User Interference. Performance improvements with Forward Error Correction are included.

  11. Expression of specific chemokines and chemokine receptors in the central nervous system of multiple sclerosis patients

    Sørensen, Torben Lykke; Tani, M; Jensen, J

    1999-01-01

    Chemokines direct tissue invasion by specific leukocyte populations. Thus, chemokines may play a role in multiple sclerosis (MS), an idiopathic disorder in which the central nervous system (CNS) inflammatory reaction is largely restricted to mononuclear phagocytes and T cells. We asked whether...

  12. Residue-based Coordinated Selection and Parameter Design of Multiple Power System Stabilizers (PSSs)

    Su, Chi; Hu, Weihao; Fang, Jiakun

    2013-01-01

    data from time domain simulations. Then a coordinated approach for multiple PSS selection and parameter design based on residue method is proposed and realized in MATLAB m-files. Particle swarm optimization (PSO) is adopted in the coordination process. The IEEE 39-bus New England system model...

  13. The computer-aided design of a servo system as a multiple-criteria decision problem

    Udink ten Cate, A.J.

    1986-01-01

    This paper treats the selection of controller gains of a servo system as a multiple-criteria decision problem. In contrast to the usual optimization-based approaches to computer-aided design, inequality constraints are included in the problem as unconstrained objectives. This considerably simplifies

  14. Addressing Single and Multiple Bad Data in the Modern PMU-based Power System State Estimation

    Khazraj, Hesam; Silva, Filipe Miguel Faria da; Bak, Claus Leth

    2017-01-01

    utilization in state estimation can detect and identify single and multiple bad data in redundant and critical measurements. To validate simulations, IEEE 30 bus system are implemented in PowerFactory and Matlab is used to solve proposed state estimation using postprocessing of PMUs and mixed methods. Bad...

  15. Construction of a food-grade multiple-copy integration system for Lactococcus lactis

    Leenhouts, K.; Bolhuis, A.; Venema, G.; Kok, J.

    A food-grade vector system was developed that allows stable integration of multiple plasmid copies in the chromosome of Lactococcus lactis. The vector consists of the plus origin of replication (Ori(+)) of the lactococcal plasmid pWV01, the sucrose genes of the lactic acid bacterium Pediococcus

  16. A simple optical fibre-linked remote control system for multiple devices

    We report on the development of a simple control system which can handle multiple devices through an optical fibre data link. The devices are controlled using a set of DACs through serial data communication via a serial port of a PC. Serial data from the PC get converted to parallel mode using a homemade “serial in ...

  17. Continued Kinematic and Photometric Investigations of Hierarchical Solar-type Multiple Star Systems

    Roberts, Lewis C. Jr.; Marinan, Anne D. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena CA 91109 (United States); Tokovinin, Andrei [Cerro Tololo Inter-American Observatory, Casilla 603, La Serena (Chile); Mason, Brian D., E-mail: lewis.c.roberts@jpl.nasa.gov [U.S. Naval Observatory, 3450 Massachusetts Avenue, NW, Washington, DC 20392-5420 (United States)

    2017-03-01

    We observed 15 of the solar-type binaries within 67 pc of the Sun previously observed by the Robo-AO system in the visible, with the PHARO near-infrared camera and the PALM-3000 adaptive optics system on the 5 m Hale telescope. The physical status of the binaries is confirmed through common proper motion and detection of orbital motion. In the process, we detected a new candidate companion to HIP 95309. We also resolved the primary of HIP 110626 into a close binary, making that system a triple. These detections increase the completeness of the multiplicity survey of the solar-type stars within 67 pc of the Sun. Combining our observations of HIP 103455 with archival astrometric measurements and RV measurements, we are able to compute the first orbit of HIP 103455, showing that the binary has a 68 year period. We place the components on a color–magnitude diagram and discuss each multiple system individually.

  18. Code division multiple-access techniques in optical fiber networks. II - Systems performance analysis

    Salehi, Jawad A.; Brackett, Charles A.

    1989-08-01

    A technique based on optical orthogonal codes was presented by Salehi (1989) to establish a fiber-optic code-division multiple-access (FO-CDMA) communications system. The results are used to derive the bit error rate of the proposed FO-CDMA system as a function of data rate, code length, code weight, number of users, and receiver threshold. The performance characteristics for a variety of system parameters are discussed. A means of reducing the effective multiple-access interference signal by placing an optical hard-limiter at the front end of the desired optical correlator is presented. Performance calculations are shown for the FO-CDMA with an ideal optical hard-limiter, and it is shown that using a optical hard-limiter would, in general, improve system performance.

  19. Performance enhancement of optical code-division multiple-access systems using transposed modified Walsh code

    Sikder, Somali; Ghosh, Shila

    2018-02-01

    This paper presents the construction of unipolar transposed modified Walsh code (TMWC) and analysis of its performance in optical code-division multiple-access (OCDMA) systems. Specifically, the signal-to-noise ratio, bit error rate (BER), cardinality, and spectral efficiency were investigated. The theoretical analysis demonstrated that the wavelength-hopping time-spreading system using TMWC was robust against multiple-access interference and more spectrally efficient than systems using other existing OCDMA codes. In particular, the spectral efficiency was calculated to be 1.0370 when TMWC of weight 3 was employed. The BER and eye pattern for the designed TMWC were also successfully obtained using OptiSystem simulation software. The results indicate that the proposed code design is promising for enhancing network capacity.

  20. Linear systems with unstructured multiplicative uncertainty: Modeling and robust stability analysis.

    Radek Matušů

    Full Text Available This article deals with continuous-time Linear Time-Invariant (LTI Single-Input Single-Output (SISO systems affected by unstructured multiplicative uncertainty. More specifically, its aim is to present an approach to the construction of uncertain models based on the appropriate selection of a nominal system and a weight function and to apply the fundamentals of robust stability investigation for considered sort of systems. The initial theoretical parts are followed by three extensive illustrative examples in which the first order time-delay, second order and third order plants with parametric uncertainty are modeled as systems with unstructured multiplicative uncertainty and subsequently, the robust stability of selected feedback loops containing constructed models and chosen controllers is analyzed and obtained results are discussed.

  1. MetaTracker: integration and abstraction of 3D motion tracking data from multiple hardware systems

    Kopecky, Ken; Winer, Eliot

    2014-06-01

    Motion tracking has long been one of the primary challenges in mixed reality (MR), augmented reality (AR), and virtual reality (VR). Military and defense training can provide particularly difficult challenges for motion tracking, such as in the case of Military Operations in Urban Terrain (MOUT) and other dismounted, close quarters simulations. These simulations can take place across multiple rooms, with many fast-moving objects that need to be tracked with a high degree of accuracy and low latency. Many tracking technologies exist, such as optical, inertial, ultrasonic, and magnetic. Some tracking systems even combine these technologies to complement each other. However, there are no systems that provide a high-resolution, flexible, wide-area solution that is resistant to occlusion. While frameworks exist that simplify the use of tracking systems and other input devices, none allow data from multiple tracking systems to be combined, as if from a single system. In this paper, we introduce a method for compensating for the weaknesses of individual tracking systems by combining data from multiple sources and presenting it as a single tracking system. Individual tracked objects are identified by name, and their data is provided to simulation applications through a server program. This allows tracked objects to transition seamlessly from the area of one tracking system to another. Furthermore, it abstracts away the individual drivers, APIs, and data formats for each system, providing a simplified API that can be used to receive data from any of the available tracking systems. Finally, when single-piece tracking systems are used, those systems can themselves be tracked, allowing for real-time adjustment of the trackable area. This allows simulation operators to leverage limited resources in more effective ways, improving the quality of training.

  2. Transshipment policies for systems with multiple retailers and two demand classes

    Atan, Z.; Snyder, L.V.; Wilson, G.R.

    2018-01-01

    Many retailers discriminate among their customers based on their value to the firm. Instead of losing a customer due to this discrimination or lack of inventory, a retailer might prefer to place a transshipment request with other retailers to satisfy the customer’s demand. The system as a whole can benefit from this type of transshipments. In this paper, we study a problem of a centrally controlled system with multiple retailers. Each retailer serves two types of customers: high priority and ...

  3. Solid-State Neutron Multiplicity Counting System Using Commercial Off-the-Shelf Semiconductor Detectors

    Rozhdestvenskyy, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-08-09

    This work iterates on the first demonstration of a solid-state neutron multiplicity counting system developed at Lawrence Livermore National Laboratory by using commercial off-the-shelf detectors. The system was demonstrated to determine the mass of a californium-252 neutron source within 20% error requiring only one-hour measurement time with 20 cm2 of active detector area.

  4. A Multiple Items EPQ/EOQ Model for a Vendor and Multiple Buyers System with Considering Continuous and Discrete Demand Simultaneously

    Jonrinaldi; Rahman, T.; Henmaidi; Wirdianto, E.; Zhang, D. Z.

    2018-03-01

    This paper proposed a mathematical model for multiple items Economic Production and Order Quantity (EPQ/EOQ) with considering continuous and discrete demand simultaneously in a system consisting of a vendor and multiple buyers. This model is used to investigate the optimal production lot size of the vendor and the number of shipments policy of orders to multiple buyers. The model considers the multiple buyers’ holding cost as well as transportation cost, which minimize the total production and inventory costs of the system. The continuous demand from any other customers can be fulfilled anytime by the vendor while the discrete demand from multiple buyers can be fulfilled by the vendor using the multiple delivery policy with a number of shipments of items in the production cycle time. A mathematical model is developed to illustrate the system based on EPQ and EOQ model. Solution procedures are proposed to solve the model using a Mixed Integer Non Linear Programming (MINLP) and algorithm methods. Then, the numerical example is provided to illustrate the system and results are discussed.

  5. The effect of multiple external representations (MERs) worksheets toward complex system reasoning achievement

    Sumarno; Ibrahim, M.; Supardi, Z. A. I.

    2018-03-01

    The application of a systems approach to assessing biological systems provides hope for a coherent understanding of cell dynamics patterns and their relationship to plant life. This action required the reasoning about complex systems. In other sides, there were a lot of researchers who provided the proof about the instructional successions. They involved the multiple external representations which improved the biological learning. The researcher conducted an investigation using one shoot case study design which involved 30 students in proving that the MERs worksheets could affect the student's achievement of reasoning about complex system. The data had been collected based on test of reasoning about complex system and student's identification result who worked through MERs. The result showed that only partially students could achieve reasoning about system complex, but their MERs skill could support their reasoning ability of complex system. This study could bring a new hope to develop the MERs worksheet as a tool to facilitate the reasoning about complex system.

  6. Implementation of Multiple Host Nodes in Wireless Sensing Node Network System for Landslide Monitoring

    Bin Abas, Faizulsalihin; Takayama, Shigeru

    2015-01-01

    This paper proposes multiple host nodes in Wireless Sensing Node Network System (WSNNS) for landslide monitoring. As landslide disasters damage monitoring system easily, one major demand in landslide monitoring is the flexibility and robustness of the system to evaluate the current situation in the monitored area. For various reasons WSNNS can provide an important contribution to reach that aim. In this system, acceleration sensors and GPS are deployed in sensing nodes. Location information by GPS, enable the system to estimate network topology and enable the system to perceive the location in emergency by monitoring the node mode. Acceleration sensors deployment, capacitate this system to detect slow mass movement that can lead to landslide occurrence. Once deployed, sensing nodes self-organize into an autonomous wireless ad hoc network. The measurement parameter data from sensing nodes is transmitted to Host System via host node and ''Cloud'' System. The implementation of multiple host nodes in Local Sensing Node Network System (LSNNS), improve risk- management of the WSNNS for real-time monitoring of landslide disaster

  7. Implementation of Multiple Host Nodes in Wireless Sensing Node Network System for Landslide Monitoring

    Abas, Faizulsalihin bin; Takayama, Shigeru

    2015-02-01

    This paper proposes multiple host nodes in Wireless Sensing Node Network System (WSNNS) for landslide monitoring. As landslide disasters damage monitoring system easily, one major demand in landslide monitoring is the flexibility and robustness of the system to evaluate the current situation in the monitored area. For various reasons WSNNS can provide an important contribution to reach that aim. In this system, acceleration sensors and GPS are deployed in sensing nodes. Location information by GPS, enable the system to estimate network topology and enable the system to perceive the location in emergency by monitoring the node mode. Acceleration sensors deployment, capacitate this system to detect slow mass movement that can lead to landslide occurrence. Once deployed, sensing nodes self-organize into an autonomous wireless ad hoc network. The measurement parameter data from sensing nodes is transmitted to Host System via host node and "Cloud" System. The implementation of multiple host nodes in Local Sensing Node Network System (LSNNS), improve risk- management of the WSNNS for real-time monitoring of landslide disaster.

  8. Identification of optimal strategies for energy management systems planning under multiple uncertainties

    Cai, Y.P.; Huang, G.H.; Yang, Z.F.; Tan, Q.

    2009-01-01

    Management of energy resources is crucial for many regions throughout the world. Many economic, environmental and political factors are having significant effects on energy management practices, leading to a variety of uncertainties in relevant decision making. The objective of this research is to identify optimal strategies in the planning of energy management systems under multiple uncertainties through the development of a fuzzy-random interval programming (FRIP) model. The method is based on an integration of the existing interval linear programming (ILP), superiority-inferiority-based fuzzy-stochastic programming (SI-FSP) and mixed integer linear programming (MILP). Such a FRIP model allows multiple uncertainties presented as interval values, possibilistic and probabilistic distributions, as well as their combinations within a general optimization framework. It can also be used for facilitating capacity-expansion planning of energy-production facilities within a multi-period and multi-option context. Complexities in energy management systems can be systematically reflected, thus applicability of the modeling process can be highly enhanced. The developed method has then been applied to a case of long-term energy management planning for a region with three cities. Useful solutions for the planning of energy management systems were generated. Interval solutions associated with different risk levels of constraint violation were obtained. They could be used for generating decision alternatives and thus help decision makers identify desired policies under various economic and system-reliability constraints. The solutions can also provide desired energy resource/service allocation and capacity-expansion plans with a minimized system cost, a maximized system reliability and a maximized energy security. Tradeoffs between system costs and constraint-violation risks could be successfully tackled, i.e., higher costs will increase system stability, while a desire for lower

  9. OFD1, as a Ciliary Protein, Exhibits Neuroprotective Function in Photoreceptor Degeneration Models.

    Juan Wang

    Full Text Available Ofd1 is a newly identified causative gene for Retinitis pigmentosa (RP, a photoreceptor degenerative disease. This study aimed to examine Ofd1 localization in retina and further to investigate its function in photoreceptor degeneration models. Ofd1 localization in rat retina was examined using immunofluorescence. N-methyl-N-nitrosourea (MNU-induced rats and Royal College of Surgeons (RCS rats were used as photoreceptor degeneration models. The expression pattern of Ofd1, other ciliary associated genes and Wnt signaling pathway genes were examined in rat models. Furthermore, pEGFP-Ofd1-CDS and pSUPER-Ofd1-shRNA were constructed to overexpress and knockdown the expression level in 661W and R28 cells. MNU was also used to induce cell death. Cilia formation was observed using immunocytochemistry (ICC. Reactive oxygen species (ROS were detected using the 2', 7'-Dichlorofluorescin diacetate (DCFH-DA assay. Apoptosis genes expression was examined using qRT-PCR, Western blotting and fluorescence-activated cell sorting (FACS. Ofd1 localized to outer segments of rat retina photoreceptors. Ofd1 and other ciliary proteins expression levels increased from the 1st and 4th postnatal weeks and decreased until the 6th week in the RCS rats, while their expression consistently decreased from the 1st and 7th day in the MNU rats. Moreover, Wnt signaling pathway proteins expression was significantly up-regulated in both rat models. Knockdown of Ofd1 expression resulted in a smaller population, shorter length of cell cilia, and lower cell viability. Ofd1 overexpression partially attenuated MNU toxic effects by reducing ROS levels and mitigating apoptosis. To the best of our knowledge, this is the first study demonstrating Ofd1 localization and its function in rat retina and in retinal degeneration rat models. Ofd1 plays a role in controlling photoreceptor cilium length and number. Importantly, it demonstrates a neuroprotective function by protecting the photoreceptor

  10. Robust Inventory System Optimization Based on Simulation and Multiple Criteria Decision Making

    Ahmad Mortazavi

    2014-01-01

    Full Text Available Inventory management in retailers is difficult and complex decision making process which is related to the conflict criteria, also existence of cyclic changes and trend in demand is inevitable in many industries. In this paper, simulation modeling is considered as efficient tool for modeling of retailer multiproduct inventory system. For simulation model optimization, a novel multicriteria and robust surrogate model is designed based on multiple attribute decision making (MADM method, design of experiments (DOE, and principal component analysis (PCA. This approach as a main contribution of this paper, provides a framework for robust multiple criteria decision making under uncertainty.

  11. Central nervous system involvement in primary Sjogren`s syndrome manifesting as multiple sclerosis.

    Liu, Jing-Yao; Zhao, Teng; Zhou, Chun-Kui

    2014-04-01

    Central nervous system symptoms in patients with primary Sjogren`s syndrome are rare. They can present as extraglandular manifestations and require a differential diagnosis from multiple sclerosis. Due to a variety of presentations, Sjogren`s syndrome with neurologic involvement may be difficult to diagnose. Here, we report a case of a 75-year-old woman who was first diagnosed with multiple sclerosis in 2010, but who was subsequently diagnosed with primary Sjogren`s syndrome 2 years later after showing signs of atypical neurologic manifestations. Therefore, primary Sjogren`s syndrome should be suspected in patients who present with atypical clinical and radiologic neurologic manifestations.

  12. Generalized statistical criterion for distinguishing random optical groupings from physical multiple systems

    Anosova, Z.P.

    1988-01-01

    A statistical criterion is proposed for distinguishing between random and physical groupings of stars and galaxies. The criterion is applied to nearby wide multiple stars, triplets of galaxies in the list of Karachentsev, Karachentseva, and Shcherbanovskii, and double galaxies in the list of Dahari, in which the principal components are Seyfert galaxies. Systems that are almost certainly physical, probably physical, probably optical, and almost certainly optical are identified. The limiting difference between the radial velocities of the components of physical multiple galaxies is estimated

  13. Robust Fault Tolerant Control for a Class of Time-Delay Systems with Multiple Disturbances

    Songyin Cao

    2013-01-01

    Full Text Available A robust fault tolerant control (FTC approach is addressed for a class of nonlinear systems with time delay, actuator faults, and multiple disturbances. The first part of the multiple disturbances is supposed to be an uncertain modeled disturbance and the second one represents a norm-bounded variable. First, a composite observer is designed to estimate the uncertain modeled disturbance and actuator fault simultaneously. Then, an FTC strategy consisting of disturbance observer based control (DOBC, fault accommodation, and a mixed H2/H∞ controller is constructed to reconfigure the considered systems with disturbance rejection and attenuation performance. Finally, simulations for a flight control system are given to show the efficiency of the proposed approach.

  14. Multiple continuous coverage of the earth based on multi-satellite systems with linear structure

    Saulskiy, V. K.

    2009-04-01

    A new and wider definition is given to multi-satellite systems with linear structure (SLS), and efficiency of their application to multiple continuous coverage of the Earth is substantiated. Owing to this widening, SLS have incorporated already well-recognized “polar systems” by L. Rider and W.S. Adams, “kinematically regular systems” by G.V. Mozhaev, and “delta-systems” by J.G. Walker, as well as “near-polar systems” by Yu.P. Ulybyshev, and some other satellite constellations unknown before. A universal method of SLS optimization is presented, valid for any values of coverage multiplicity and the number of satellites in a system. The method uses the criterion of minimum radius of a circle seen from a satellite on the surface of the globe. Among the best SLS found in this way there are both systems representing the well-known classes mentioned above and new orbit constellations of satellites.

  15. MRI of the spinocerebellar degeneration (multiple system atrophy, Holmes type, and Menzel-Joseph type)

    Mukai, Eiichiro; Makino, Naoki.

    1991-01-01

    We have analyzed MRI in 33 patients with several forms of spinocerebellar degeneration; 17 with multiple system atrophy, 10 with Holmes type, and 6 with Menzel-Joseph type. The MRIs were obtained using a 1.5-T GEMR System. Patients with multiple system atrophy demonstrated: atrophy of the brain stem, particularly basis pontis; decreased signal intensity of the white matter of pons; atrophy of the white matter of cerebellum; atrophy and decreased signal intensity of the putamen, particularly along their lateral and posterior portions; and atrophy of the cerebrum. Patients with Holmes type showed: atrophy of the cerebellum; atrophy of the vermis more than hemispheres; and nuclei of the cerebellum with no decreased intensity on T 2 -weighted sequences. Patients with Menzel-Joseph type demonstrated moderate atrophy of the brain stem and mild atrophy of the white matter of cerebellum. MRI is a useful diagnostic tool in the management of the spinocerebellar degeneration. (author)

  16. [Construction of multiple drug release system based on components of traditional Chinese medicine].

    Liu, Dan; Jia, Xiaobin; Yu, Danhong; Zhang, Zhenhai; Sun, E

    2012-08-01

    With the development of the modernization drive of traditional Chinese medicine (TCM) preparations, new-type TCM dosage forms research have become a hot spot in the field. Because of complexity of TCM components as well as uncertainty of material base, there is still not a scientific system for modern TCM dosage forms so far. Modern TCM preparations inevitably take the nature of the multi-component and the general function characteristics of multi-link and multi-target into account. The author suggests building a multiple drug release system for TCM using diverse preparation techniques and drug release methods at levels on the basis the nature and function characteristics of TCM components. This essay expounds elaborates the ideas to build the multiple traditional Chinese medicine release system, theoretical basis, preparation techniques and assessment system, current problems and solutions, in order to build a multiple TCM release system with a view of enhancing the bioavailability of TCM components and provide a new form for TCM preparations.

  17. Multi-objective optimization of linear multi-state multiple sliding window system

    Konak, Abdullah; Kulturel-Konak, Sadan; Levitin, Gregory

    2012-01-01

    This paper considers the optimal element sequencing in a linear multi-state multiple sliding window system that consists of n linearly ordered multi-state elements. Each multi-state element can have different states: from complete failure up to perfect functioning. A performance rate is associated with each state. The failure of type i in the system occurs if for any i (1≤i≤I) the cumulative performance of any r i consecutive elements is lower than w i . The element sequence strongly affects the probability of any type of system failure. The sequence that minimizes the probability of certain type of failure can provide high probability of other types of failures. Therefore the optimization problem for the multiple sliding window system is essentially multi-objective. The paper formulates and solves the multi-objective optimization problem for the multiple sliding window systems. A multi-objective Genetic Algorithm is used as the optimization engine. Illustrative examples are presented.

  18. Hybrid wireless-over-fiber transmission system based on multiple injection-locked FP LDs.

    Li, Chung-Yi; Lu, Hai-Han; Chu, Chien-An; Ying, Cheng-Ling; Lu, Ting-Chien; Peng, Peng-Chun

    2015-07-27

    A hybrid wireless-over-fiber (WoF) transmission system based on multiple injection-locked Fabry-Perot laser diodes (FP LDs) is proposed and experimentally demonstrated. Unlike the traditional hybrid WoF transmission systems that require multiple distributed feedback (DFB) LDs to support different kinds of services, the proposed system employs multiple injection-locked FP LDs to provide different kinds of applications. Such a hybrid WoF transmission system delivers downstream intensity-modulated 20-GHz microwave (MW)/60-GHz millimeter-wave (MMW)/550-MHz cable television (CATV) signals and upstream phase-remodulated 20-GHz MW signal. Excellent bit error rate (BER), carrier-to-noise ratio (CNR), composite second-order (CSO), and composite triple-beat (CTB) are observed over a 40-km single-mode fiber (SMF) and a 4-m radio frequency (RF) wireless transport. Such a hybrid WoF transmission system has practical applications for fiber-wireless convergence to provide broadband integrated services, including telecommunication, data communication, and CATV services.

  19. Free-space optical code-division multiple-access system design

    Jeromin, Lori L.; Kaufmann, John E.; Bucher, Edward A.

    1993-08-01

    This paper describes an optical direct-detection multiple access communications system for free-space satellite networks utilizing code-division multiple-access (CDMA) and forward error correction (FEC) coding. System performance is characterized by how many simultaneous users operating at data rate R can be accommodated in a signaling bandwidth W. The performance of two CDMA schemes, optical orthogonal codes (OOC) with FEC and orthogonal convolutional codes (OCC), is calculated and compared to information-theoretic capacity bounds. The calculations include the effects of background and detector noise as well as nonzero transmitter extinction ratio and power imbalance among users. A system design for 10 kbps multiple-access communications between low-earth orbit satellites is given. With near- term receiver technology and representative system losses, a 15 W peak-power transmitter provides 10-6 BER performance with seven interfering users and full moon background in the receiver FOV. The receiver employs an array of discrete wide-area avalanche photodiodes (APD) for wide field of view coverage. Issues of user acquisition and synchronization, implementation technology, and system scalability are also discussed.

  20. NINL and DZANK1 Co-function in Vesicle Transport and Are Essential for Photoreceptor Development in Zebrafish

    Dona, M.; Bachmann-Gagescu, R.; Texier, Y.; Toedt, G.; Hetterschijt, L.; Tonnaer, E.L.; Peters, T.A.; Beersum, S.E.C. van; Bergboer, J.G.M.; Horn, N.; Vrieze, E. de; Slijkerman, R.W.N.; Reeuwijk, J. van; Flik, G.; Keunen, J.E.E.; Ueffing, M.; Gibson, T.J.; Roepman, R.; Boldt, K.; Kremer, H.; Wijk, E. van

    2015-01-01

    Ciliopathies are Mendelian disorders caused by dysfunction of cilia, ubiquitous organelles involved in fluid propulsion (motile cilia) or signal transduction (primary cilia). Retinal dystrophy is a common phenotypic characteristic of ciliopathies since photoreceptor outer segments are specialized

  1. S-band multiple-access interference study for advanced tracking and data relay satellite systems

    Peng, Wei-Chung; Yang, Chau-Chin

    1990-01-01

    The results of a study on the effect of mutual interference among S-band multiple access (SMA) system users of advanced tracking and data relay satellite system (ATDRSS) are presented. In the ATDRSS era, the SMA system is required to support data rates ranging from 10 kb/s to 3 Mb/s. The system will consist of four advanced tracking and data relay satellites (ATDRS) each supporting up to five telemetry links. All users have 10 MHz bandwidth with their carrier frequency equal to 2.2875 GHz. A hybrid SDMA/CDMA scheme is used to mitigate the effect of the interference among system users. SMA system interference probability is evaluated with CLASS software. User link margin degradation due to mutual interference between two users is evaluated. System interference probability is evaluated for the projected 1996 mission model, a reference mission model, and a modified reference mission model.

  2. A New Chaotic System with Multiple Attractors: Dynamic Analysis, Circuit Realization and S-Box Design

    Qiang Lai

    2017-12-01

    Full Text Available This paper reports about a novel three-dimensional chaotic system with three nonlinearities. The system has one stable equilibrium, two stable equilibria and one saddle node, two saddle foci and one saddle node for different parameters. One salient feature of this novel system is its multiple attractors caused by different initial values. With the change of parameters, the system experiences mono-stability, bi-stability, mono-periodicity, bi-periodicity, one strange attractor, and two coexisting strange attractors. The complex dynamic behaviors of the system are revealed by analyzing the corresponding equilibria and using the numerical simulation method. In addition, an electronic circuit is given for implementing the chaotic attractors of the system. Using the new chaotic system, an S-Box is developed for cryptographic operations. Moreover, we test the performance of this produced S-Box and compare it to the existing S-Box studies.

  3. System Reliability Evaluation of Data Transmission in Commercial Banks with Multiple Branches

    Yi-Kuei Lin

    2014-01-01

    Full Text Available The main purpose of this paper is to assess the system reliability of electronic transaction data transmissions made by commercial banks in terms of stochastic flow network. System reliability is defined as the probability of demand satisfaction and it can be used to measure quality of service. In this paper, we study the system reliability of data transmission from the headquarters of a commercial bank to its multiple branches. The network structure of the bank and the probability of successful data transmission are obtained through the collection of real data. The system reliability, calculated using the minimal path method and the recursive sum of disjoint products algorithm, provides banking managers with a view to comprehend the current state of the entire system. Besides, the system reliability can be used not only as a measurement of quality of service, but also an improvement reference of the system by adopting sensitivity analysis.

  4. A silicon multiplicity detector system for an experiment on the interaction of antiprotons with nuclei at BNL

    Ahmad, S.; Bonner, B.E.; Buchanan, J.A.; Clement, J.M.; Empl, A.; Mutchler, G.S.; Toshkov, S.; Chan, C.S.; Kramer, M.A.; Lindenbaum, S.J.; Hallman, T.J.; Madansky, L.; Peaslee, D.C.

    1991-01-01

    A Large Angle Multiplicity Detector (LAMD) system has been developed and used at the BNL experiment E854: Antiproton Nucleus Interactions. This system performed well with an energetic antiproton beam. Charged particle multiplicity distributions from pbar annihilations were measured. We discuss the design and performance of the LAMD system in this paper. 6 refs., 10 figs

  5. Multi-agent System for Off-line Coordinated Motion Planning of Multiple Industrial Robots

    Shital S. Chiddarwar

    2011-03-01

    Full Text Available This article presents an agent based framework for coordinated motion planning of multiple robots. The emerging paradigm of agent based systems is implemented to address various issues related to safe and fast task execution when multiple robots share a common workspace. In the proposed agent based framework, each issue vital for coordinated motion planning of multiple robots and every robot participating in coordinated task is considered as an agent. The identified agents are interfaced with each other in order to incorporate the desired flexibility in the developed framework. This framework gives a complete strategy for determination of optimal trajectories of robots working in coordination with due consideration to their kinematic, dynamic and payload constraint. The complete architecture of the proposed framework and the detailed discussion on various modules are covered in this paper.

  6. Employing optical code division multiple access technology in the all fiber loop vibration sensor system

    Tseng, Shin-Pin; Yen, Chih-Ta; Syu, Rong-Shun; Cheng, Hsu-Chih

    2013-12-01

    This study proposes a spectral amplitude coding-optical code division multiple access (SAC-OCDMA) framework to access the vibration frequency of a test object on the all fiber loop vibration sensor (AFLVS). Each user possesses an individual SAC, and fiber Bragg grating (FBG) encoders/decoders using multiple FBG arrays were adopted, providing excellent orthogonal properties in the frequency domain. The system also mitigates multiple access interference (MAI) among users. When an optical fiber is bent to a point exceeding the critical radius, the fiber loop sensor becomes sensitive to external physical parameters (e.g., temperature, strain, and vibration). The AFLVS involves placing a fiber loop with a specific radius on a designed vibration platform.

  7. Distributed Containment Control for Multiple Unknown Second-Order Nonlinear Systems With Application to Networked Lagrangian Systems.

    Mei, Jie; Ren, Wei; Li, Bing; Ma, Guangfu

    2015-09-01

    In this paper, we consider the distributed containment control problem for multiagent systems with unknown nonlinear dynamics. More specifically, we focus on multiple second-order nonlinear systems and networked Lagrangian systems. We first study the distributed containment control problem for multiple second-order nonlinear systems with multiple dynamic leaders in the presence of unknown nonlinearities and external disturbances under a general directed graph that characterizes the interaction among the leaders and the followers. A distributed adaptive control algorithm with an adaptive gain design based on the approximation capability of neural networks is proposed. We present a necessary and sufficient condition on the directed graph such that the containment error can be reduced as small as desired. As a byproduct, the leaderless consensus problem is solved with asymptotical convergence. Because relative velocity measurements between neighbors are generally more difficult to obtain than relative position measurements, we then propose a distributed containment control algorithm without using neighbors' velocity information. A two-step Lyapunov-based method is used to study the convergence of the closed-loop system. Next, we apply the ideas to deal with the containment control problem for networked unknown Lagrangian systems under a general directed graph. All the proposed algorithms are distributed and can be implemented using only local measurements in the absence of communication. Finally, simulation examples are provided to show the effectiveness of the proposed control algorithms.

  8. Usher protein functions in hair cells and photoreceptors

    Cosgrove, Dominic; Zallocchi, Marisa

    2013-01-01

    The 10 different genes associated with the deaf/blind disorder, Usher syndrome, encode a number of structurally and functionally distinct proteins, most expressed as multiple isoforms/protein variants. Functional characterization of these proteins suggests a role in stereocilia development in cochlear hair cells, likely owing to adhesive interactions in hair bundles. In mature hair cells, homodimers of the Usher cadherins, cadherin 23 and protocadherin 15, interact to form a structural fiber,...

  9. Multiple-Parameter, Low-False-Alarm Fire-Detection Systems

    Hunter, Gary W.; Greensburg, Paul; McKnight, Robert; Xu, Jennifer C.; Liu, C. C.; Dutta, Prabir; Makel, Darby; Blake, D.; Sue-Antillio, Jill

    2007-01-01

    Fire-detection systems incorporating multiple sensors that measure multiple parameters are being developed for use in storage depots, cargo bays of ships and aircraft, and other locations not amenable to frequent, direct visual inspection. These systems are intended to improve upon conventional smoke detectors, now used in such locations, that reliably detect fires but also frequently generate false alarms: for example, conventional smoke detectors based on the blockage of light by smoke particles are also affected by dust particles and water droplets and, thus, are often susceptible to false alarms. In contrast, by utilizing multiple parameters associated with fires, i.e. not only obscuration by smoke particles but also concentrations of multiple chemical species that are commonly generated in combustion, false alarms can be significantly decreased while still detecting fires as reliably as older smoke-detector systems do. The present development includes fabrication of sensors that have, variously, micrometer- or nanometer-sized features so that such multiple sensors can be integrated into arrays that have sizes, weights, and power demands smaller than those of older macroscopic sensors. The sensors include resistors, electrochemical cells, and Schottky diodes that exhibit different sensitivities to the various airborne chemicals of interest. In a system of this type, the sensor readings are digitized and processed by advanced signal-processing hardware and software to extract such chemical indications of fires as abnormally high concentrations of CO and CO2, possibly in combination with H2 and/or hydrocarbons. The system also includes a microelectromechanical systems (MEMS)-based particle detector and classifier device to increase the reliability of measurements of chemical species and particulates. In parallel research, software for modeling the evolution of a fire within an aircraft cargo bay has been developed. The model implemented in the software can

  10. Optical coherence tomography of the photoreceptor layer in the healthy eye and in eyes with hereditary macular dystrophy

    Stur, M.; Hermann, B.; Drexler, W.; Unterhuber, A.; Sattmann, H.; Ergun, E.; Wirtitsch, M.

    2007-01-01

    Optical coherence tomography is primarily used for the evaluation of pronounced alterations of the retinal architecture, such as in macular holes, epiretinal gliosis, intra- and subretinal fluid accumulation as well as retinal atrophy. Ultrahigh resolution OCT devices also allow the assessment of discrete alterations of the photoreceptor layer and the retinal pigment epithelium. On the basis of cases from two different macular dystrophies, the importance of the evaluation of the photoreceptor layer and its correlation with visual acuity is demonstrated.(author) [de

  11. Cubic systems with invariant affine straight lines of total parallel multiplicity seven

    Alexandru Suba

    2013-12-01

    Full Text Available In this article, we study the planar cubic differential systems with invariant affine straight lines of total parallel multiplicity seven. We classify these system according to their geometric properties encoded in the configurations of invariant straight lines. We show that there are only 17 different topological phase portraits in the Poincar\\'e disc associated to this family of cubic systems up to a reversal of the sense of their orbits, and we provide representatives of every class modulo an affine change of variables and rescaling of the time variable.

  12. On Acoustic Feedback Cancellation Using Probe Noise in Multiple-Microphone and Single-Loudspeaker Systems

    Guo, Meng; Elmedyb, Thomas Bo; Jensen, Søren Holdt

    2012-01-01

    of the adaptive estimation is significantly decreased when keeping the steady-state error unchanged. The goal of this work is to derive analytic expressions for the system behavior such as convergence rate and steady-state error for a multiple-microphone and single-loudspeaker audio system, where the acoustic...... feedback cancellation is carried out using a probe noise signal. The derived results show how different system parameters and signal properties affect the cancellation performance, and the results explain theoretically the decreased convergence rate. Understanding this is important for making further...

  13. Research on the reliability of friction system under combined additive and multiplicative random excitations

    Sun, Jiaojiao; Xu, Wei; Lin, Zifei

    2018-01-01

    In this paper, the reliability of a non-linearly damped friction oscillator under combined additive and multiplicative Gaussian white noise excitations is investigated. The stochastic averaging method, which is usually applied to the research of smooth system, has been extended to the study of the reliability of non-smooth friction system. The results indicate that the reliability of friction system can be improved by Coulomb friction and reduced by random excitations. In particular, the effect of the external random excitation on the reliability is larger than the effect of the parametric random excitation. The validity of the analytical results is verified by the numerical results.

  14. JIGSAW: Acquisition, Display and Analysis system designed to collect data from Multiple Gamma-Ray detectors

    Haywood, S.E.; Bamford, G.J.; Rester, A.C.; Coldwell, R.L.

    1992-01-01

    In this paper, the authors report on work performed to date on JIGSAW - a self contained data acquisition, display and analysis system designed to collect data form multiple gamma-ray detectors. The data acquisition system utilizes commercially available VMEbus and NIM hardware modules and the VME exec real time operating system. A Unix based software package, written in ANSI standard C and with the XII graphics routines, allows the user to view the acquired spectra. Analysis of the histograms can be performed in background during the run with the ROBFIT suite of curve fitting routines

  15. Homogeneous Stabilizer by State Feedback for Switched Nonlinear Systems Using Multiple Lyapunov Functions’ Approach

    Hui Ye

    2017-01-01

    Full Text Available This paper investigates the problem of global stabilization for a class of switched nonlinear systems using multiple Lyapunov functions (MLFs. The restrictions on nonlinearities are neither linear growth condition nor Lipschitz condition with respect to system states. Based on adding a power integrator technique, we design homogeneous state feedback controllers of all subsystems and a switching law to guarantee that the closed-loop system is globally asymptotically stable. Finally, an example is given to illustrate the validity of the proposed control scheme.

  16. Four-channel high speed synchronized acquisition multiple trigger storage measurement system

    Guo Jian; Wang Wenlian; Zhang Zhijie

    2010-01-01

    A new storage measurement system based on the CPLD, MCU and FLASH (large-capacity flash memory) is proposed. The large capacity storage characteristic of the FLASH MEMORY is used to realize multi channel synchronized acquisition and the function of multiple records and read once. The function of multi channel synchronization, high speed data acquisition, the triggering several times, and the adjustability of working parameters expands the application of storage measurement system. The storage measurement system can be used in a variety of pressure and temperature test in explosion field. (authors)

  17. Nonlinear response to the multiple sine wave excitation of a softening--hardening system

    Koplik, B.; Subudhi, M.; Curreri, J.

    1979-01-01

    In studying the earthquake response of the HTGR core, it was observed that the system can display softening--hardening characteristics. This is of great consequence in evaluating the structural safety aspects of the core. In order to obtain a better understanding of the governing parameters, an investigation was undertaken with a single-degree-of-freedom system having a softening--hardening spring characteristic and excited by multiple sine waves. A parametric study varying the input amplitudes and the spring characteristic was performed. Transients were introduced into the system, and the jump phenomena between the lower softening characteristics to the higher hardening curve was studied

  18. Mitigation of Beat Noise in Time Wavelength Optical Code-Division Multiple-Access Systems

    Bazan, Taher M.; Harle, David; Andonovic, Ivan

    2006-11-01

    This paper presents an analysis of two methods for enhancing the performance of two-dimensional time wavelength Optical code-division multiple-access systems by mitigating the effects of beat noise. The first methodology makes use of an optical hard limiter (OHL) in the receiver prior to the optical correlator; a general formula for the error probability as a function of crosstalk level for systems adopting OHLs is given, and the implications of the OHL's nonideal transfer characteristics are then examined. The second approach adopts pulse position modulation, and system performance is estimated and compared to that associated with on off keying.

  19. Two Stochastic Resonances Induced by Two Different Multiplicative Telegraphic Noises for an Electric System

    Li Jinghui

    2008-01-01

    In this paper, an electric system with two dichotomous resistors is investigated. It is shown that this system can display two stochastic resonances, which are the amplitude of the periodic response as the functions of the two dichotomous resistors strengthes respectively. In the limits of Gaussian white noise and shot white noise (i.e., the two noises are both Gaussian white noise or shot white noise), no phenomena of resonance appear. By further study, we find that when the system is with three or more multiplicative telegraphic noises, there are three or more stochastic resonances

  20. Functional photoreceptor loss revealed with adaptive optics: an alternate cause of color blindness.

    Carroll, Joseph; Neitz, Maureen; Hofer, Heidi; Neitz, Jay; Williams, David R

    2004-06-01

    There is enormous variation in the X-linked L/M (long/middle wavelength sensitive) gene array underlying "normal" color vision in humans. This variability has been shown to underlie individual variation in color matching behavior. Recently, red-green color blindness has also been shown to be associated with distinctly different genotypes. This has opened the possibility that there may be important phenotypic differences within classically defined groups of color blind individuals. Here, adaptive optics retinal imaging has revealed a mechanism for producing dichromatic color vision in which the expression of a mutant cone photopigment gene leads to the loss of the entire corresponding class of cone photoreceptor cells. Previously, the theory that common forms of inherited color blindness could be caused by the loss of photoreceptor cells had been discounted. We confirm that remarkably, this loss of one-third of the cones does not impair any aspect of vision other than color.