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Sample records for delay eyeblink conditioning

  1. Neural Circuitry and Plasticity Mechanisms Underlying Delay Eyeblink Conditioning

    Science.gov (United States)

    Freeman, John H.; Steinmetz, Adam B.

    2011-01-01

    Pavlovian eyeblink conditioning has been used extensively as a model system for examining the neural mechanisms underlying associative learning. Delay eyeblink conditioning depends on the intermediate cerebellum ipsilateral to the conditioned eye. Evidence favors a two-site plasticity model within the cerebellum with long-term depression of…

  2. Retention and Extinction of Delay Eyeblink Conditioning Are Modulated by Central Cannabinoids

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    Steinmetz, Adam B.; Freeman, John H.

    2011-01-01

    Rats administered the cannabinoid agonist WIN55,212-2 or the antagonist SR141716A exhibit marked deficits during acquisition of delay eyeblink conditioning, as noted by Steinmetz and Freeman in an earlier study. However, the effects of these drugs on retention and extinction of eyeblink conditioning have not been assessed. The present study…

  3. Acquisition of Differential Delay Eyeblink Classical Conditioning Is Independent of Awareness

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    Smith, Christine N.; Clark, Robert E.; Manns, Joseph R.; Squire, Larry R.

    2009-01-01

    There has been debate about whether differential delay eyeblink conditioning can be acquired without awareness of the stimulus contingencies. In 4 experiments, the authors reexamined this question. Older participants were tested with a tone and white noise (Experiment 1) or with 2 tones (Experiment 2). In addition, younger participants were tested with 2 tones (Experiment 3) or with 2 tones plus the parameters from an earlier study that had reported a relationship between conditioning and awareness (Experiment 4). Participants who were designated aware of the stimulus contingencies and participants who were designated unaware exhibited equivalent levels of differential eyeblink conditioning. Awareness of stimulus contingencies is not required for differential delay eyeblink conditioning when simple conditioned stimuli are used. PMID:15727514

  4. Hippocampal and Cerebellar Single-Unit Activity During Delay and Trace Eyeblink Conditioning in the Rat

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    Green, John T.; Arenos, Jeremy D.

    2007-01-01

    In delay eyeblink conditioning, the CS overlaps with the US and only a brainstem-cerebellar circuit is necessary for learning. In trace eyeblink conditioning, the CS ends before the US is delivered and several forebrain structures, including the hippocampus, are required for learning, in addition to a brainstem-cerebellar circuit. The interstimulus interval (ISI) between CS onset and US onset is perhaps the most important factor in classical conditioning, but studies comparing delay and trace conditioning have typically not matched these procedures in this crucial factor, so it is often difficult to determine whether results are due to differences between delay and trace or to differences in ISI. In the current study, we employed a 580-ms CS-US interval for both delay and trace conditioning and compared hippocampal CA1 activity and cerebellar interpositus nucleus activity in order to determine whether a unique signature of trace conditioning exists in patterns of single-unit activity in either structure. Long-Evans rats were chronically implanted in either CA1 or interpositus with microwire electrodes and underwent either delay eyeblink conditioning, or trace eyeblink conditioning with a 300-ms trace period between CS offset and US onset. On trials with a CR in delay conditioning, CA1 pyramidal cells showed increases in activation (relative to a pre-CS baseline) during the CS-US period in sessions 1-4 that was attenuated by sessions 5-6. In contrast, on trials with a CR in trace conditioning, CA1 pyramidal cells did not show increases in activation during the CS-US period until sessions 5-6. In sessions 5-6, increases in activation were present only to the CS and not during the trace period. For rats with interpositus electrodes, activation of interpositus neurons on CR trials was present in all sessions in both delay and trace conditioning. However, activation was greater in trace compared to delay conditioning in the first half of the CS-US interval (during the

  5. Hippocampal theta phase-contingent memory retrieval in delay and trace eyeblink conditioning.

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    Waselius, Tomi; Pöllänen, Eveliina; Wikgren, Jan; Penttonen, Markku; Nokia, Miriam S

    2017-09-04

    Hippocampal theta oscillations (3-12Hz) play a prominent role in learning. It has been suggested that encoding and retrieval of memories are supported by different phases of the theta cycle. Our previous study on trace eyeblink conditioning in rabbits suggests that the timing of the conditioned stimulus (CS) in relation to theta phase affects encoding but not retrieval of the memory trace. Here, we directly tested the effects of hippocampal theta phase on memory retrieval in two experiments conducted on adult female New Zealand White rabbits. In Experiment 1, animals were trained in trace eyeblink conditioning followed by extinction, and memory retrieval was tested by presenting the CS at troughs and peaks of the theta cycle during different stages of learning. In Experiment 2, animals were trained in delay conditioning either contingent on a high level of theta or at a random neural state. Conditioning was then followed by extinction conducted either at a random state, contingent on theta trough or contingent on theta peak. Our current results indicate that the phase of theta at CS onset has no effect on the performance of the behavioral learned response at any stage of classical eyeblink conditioning or extinction. In addition, theta-contingent trial presentation does not improve learning during delay eyeblink conditioning. The results are consistent with our earlier findings and suggest that the theta phase alone is not sufficient to affect learning at the behavioral level. It seems that the retrieval of recently acquired memories and consequently performing a learned response is moderated by neural mechanisms other than hippocampal theta. Copyright © 2017. Published by Elsevier B.V.

  6. Facilitated acquisition of standard but not long delay classical eyeblink conditioning in behaviorally inhibited adolescents.

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    Caulfield, M D; VanMeenen, K M; Servatius, R J

    2015-02-01

    Adolescence is a key age in the development of anxiety disorders. The present study assessed the relationship between behavioral inhibition, a risk factor for anxiety typified by avoidance, and acquisition of the classically conditioned eyeblink response. 168 healthy high school students (mean age 15.7 years, 54% female) were given a battery of self-report measures including the Adult Measure of Behavioural Inhibition (AMBI). The study compared acquisition of three experimental training conditions. Two groups were given paired CS-US training: standard delay of 500-ms or long delay of 1000-ms with CS overlapping and co-terminating with a 50-ms airpuff US. A third group received unpaired training of 1000-ms CS and 50-ms airpuff US. Inhibited individuals showed greater acquisition of the conditioned eyeblink response in the 500-ms CS condition, but not in the paired 1000-ms condition. No differences in spontaneous blinks or reactivity to the stimulus were evident in the 1000-ms unpaired CS condition. Results support a relationship between associative learning and anxiety vulnerability that may be mediated by cerebellar functioning in inhibited individuals.

  7. Cerebellar-dependent associative learning is preserved in Duchenne muscular dystrophy: a study using delay eyeblink conditioning.

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    Ulrike Schara

    Full Text Available Besides progressive muscle weakness cognitive deficits have been reported in patients with Duchenne muscular dystrophy (DMD. Cerebellar dysfunction has been proposed to explain cognitive deficits at least in part. In animal models of DMD disturbed Purkinje cell function has been shown following loss of dystrophin. Furthermore there is increasing evidence that the lateral cerebellum contributes to cognitive processing. In the present study cerebellar-dependent delay eyeblink conditioning, a form of associative learning, was used to assess cerebellar function in DMD children.Delay eyeblink conditioning was examined in eight genetically defined male patients with DMD and in ten age-matched control subjects. Acquisition, timing and extinction of conditioned eyeblink responses (CR were assessed during a single conditioning session.Both groups showed a significant increase of CRs during the course of learning (block effect p < 0.001. CR acquisition was not impaired in DMD patients (mean total CR incidence 37.4 ± 17.6% as compared to control subjects (36.2 ± 17.3%; group effect p = 0.89; group by block effect p = 0.38; ANOVA with repeated measures. In addition, CR timing and extinction was not different from controls.Delay eyeblink conditioning was preserved in the present DMD patients. Because eyeblink conditioning depends on the integrity of the intermediate cerebellum, this older part of the cerebellum may be relatively preserved in DMD. The present findings agree with animal model data showing that the newer, lateral cerebellum is primarily affected in DMD.

  8. Relational and procedural memory systems in the goldfish brain revealed by trace and delay eyeblink-like conditioning.

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    Gómez, A; Rodríguez-Expósito, B; Durán, E; Martín-Monzón, I; Broglio, C; Salas, C; Rodríguez, F

    2016-12-01

    The presence of multiple memory systems supported by different neural substrata has been demonstrated in animal and human studies. In mammals, two variants of eyeblink classical conditioning, differing only in the temporal relationships between the conditioned stimulus (CS) and the unconditioned stimulus (US), have been widely used to study the neural substrata of these different memory systems. Delay conditioning, in which both stimuli coincide in time, depends on a non-relational memory system supported by the cerebellum and associated brainstem circuits. In contrast, trace conditioning, in which a stimulus-free time gap separates the CS and the US, requires a declarative or relational memory system, thus depending on forebrain structures in addition to the cerebellum. The distinction between the explicit or relational and the implicit or procedural memory systems that support trace and delay classical conditioning has been extensively studied in mammals, but studies in other vertebrate groups are relatively scarce. In the present experiment we analyzed the differential involvement of the cerebellum and the telencephalon in delay and trace eyeblink-like classical conditioning in goldfish. The results show that whereas the cerebellum lesion prevented the eyeblink-like conditioning in both procedures, the telencephalon ablation impaired exclusively the acquisition of the trace conditioning. These data showing that comparable neural systems support delay and trace eyeblink conditioning in teleost fish and mammals suggest that these separate memory systems and their neural bases could be a shared ancestral brain feature of the vertebrate lineage. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Central amygdala lesions inhibit pontine nuclei acoustic reactivity and retard delay eyeblink conditioning acquisition in adult rats.

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    Pochiro, Joseph M; Lindquist, Derick H

    2016-06-01

    In delay eyeblink conditioning (EBC) a neutral conditioned stimulus (CS; tone) is repeatedly paired with a mildly aversive unconditioned stimulus (US; periorbital electrical shock). Over training, subjects learn to produce an anticipatory eyeblink conditioned response (CR) during the CS, prior to US onset. While cerebellar synaptic plasticity is necessary for successful EBC, the amygdala is proposed to enhance eyeblink CR acquisition. In the current study, adult Long-Evans rats received bilateral sham or neurotoxic lesions of the central nucleus of the amygdala (CEA) followed by 1 or 4 EBC sessions. Fear-evoked freezing behavior, CS-mediated enhancement of the unconditioned response (UR), and eyeblink CR acquisition were all impaired in the CEA lesion rats relative to sham controls. There were also significantly fewer c-Fos immunoreactive cells in the pontine nuclei (PN)-major relays of acoustic information to the cerebellum-following the first and fourth EBC session in lesion rats. In sham rats, freezing behavior decreased from session 1 to 4, commensurate with nucleus-specific reductions in amygdala Fos+ cell counts. Results suggest delay EBC proceeds through three stages: in stage one the amygdala rapidly excites diffuse fear responses and PN acoustic reactivity, facilitating cerebellar synaptic plasticity and the development of eyeblink CRs in stage two, leading, in stage three, to a diminution or stabilization of conditioned fear responding.

  10. Choline supplementation mitigates trace, but not delay, eyeblink conditioning deficits in rats exposed to alcohol during development.

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    Thomas, Jennifer D; Tran, Tuan D

    2012-03-01

    Children exposed to alcohol prenatally suffer from a range of physical, neuropathological, and behavioral alterations, referred to as fetal alcohol spectrum disorders (FASD). Both the cerebellum and hippocampus are affected by alcohol exposure during development, which may contribute to behavioral and cognitive deficits observed in children with FASD. Despite the known neuropathology associated with prenatal alcohol exposure, many pregnant women continue to drink (heavy drinkers, in particular), creating a need to identify effective treatments for their children who are adversely affected by alcohol. We previously reported that choline supplementation can mitigate alcohol's effects on cognitive development, specifically on tasks which depend on the functional integrity of the hippocampus. The present study examined whether choline supplementation could differentially mitigate alcohol's effects on trace eyeblink classical conditioning (ECC, a hippocampal-dependent task) and delay ECC (a cerebellar-dependent task). Long-Evans rats were exposed to 5.25 g/kg/day alcohol via gastric intubation from postnatal days (PD) 4-9, a period of brain development equivalent to late gestation in humans. A sham-intubated control group was included. From PD 10-30, subjects received subcutaneous injections of 100 mg/kg choline chloride or vehicle. Beginning on PD 32-34, subjects were trained on either delay or trace eyeblink conditioning. Performance of subjects exposed to alcohol was significantly impaired on both tasks, as indicated by significant reductions in percentage and amplitude of conditioned eyeblink responses, an effect that was attenuated by choline supplementation on the trace, but not delay conditioning task. Indeed, alcohol-exposed subjects treated with choline performed at control levels on the trace eyeblink conditioning task. There were no significant main or interactive effects of sex. These data indicate that choline supplementation can significantly reduce the

  11. Children with autism spectrum disorders show abnormal conditioned response timing on delay, but not trace, eyeblink conditioning.

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    Oristaglio, J; Hyman West, S; Ghaffari, M; Lech, M S; Verma, B R; Harvey, J A; Welsh, J P; Malone, R P

    2013-09-17

    Children with autism spectrum disorder (ASD) and age-matched typically-developing (TD) peers were tested on two forms of eyeblink conditioning (EBC), a Pavlovian associative learning paradigm where subjects learn to execute an appropriately-timed eyeblink in response to a previously neutral conditioning stimulus (CS). One version of the task, trace EBC, interposes a stimulus-free interval between the presentation of the CS and the unconditioned stimulus (US), a puff of air to the eye which causes the subjects to blink. In delay EBC, the CS overlaps in time with the delivery of the US, usually with both stimuli terminating simultaneously. ASD children performed normally during trace EBC, exhibiting no differences from TD subjects with regard to the learning rate or the timing of the conditioned response. However, when subsequently tested on delay EBC, subjects with ASD displayed abnormally-timed conditioned eye blinks that began earlier and peaked sooner than those of TD subjects, consistent with previous findings. The results suggest an impaired ability of children with ASD to properly time conditioned eye blinks which appears to be specific to delay EBC. We suggest that this deficit may reflect a dysfunction of the cerebellar cortex in which increases in the intensity or duration of sensory input can temporarily disrupt the accuracy of motor timing over short temporal intervals.

  12. Implicit Memory in Monkeys: Development of a Delay Eyeblink Conditioning System with Parallel Electromyographic and High-Speed Video Measurements.

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    Yasushi Kishimoto

    Full Text Available Delay eyeblink conditioning, a cerebellum-dependent learning paradigm, has been applied to various mammalian species but not yet to monkeys. We therefore developed an accurate measuring system that we believe is the first system suitable for delay eyeblink conditioning in a monkey species (Macaca mulatta. Monkey eyeblinking was simultaneously monitored by orbicularis oculi electromyographic (OO-EMG measurements and a high-speed camera-based tracking system built around a 1-kHz CMOS image sensor. A 1-kHz tone was the conditioned stimulus (CS, while an air puff (0.02 MPa was the unconditioned stimulus. EMG analysis showed that the monkeys exhibited a conditioned response (CR incidence of more than 60% of trials during the 5-day acquisition phase and an extinguished CR during the 2-day extinction phase. The camera system yielded similar results. Hence, we conclude that both methods are effective in evaluating monkey eyeblink conditioning. This system incorporating two different measuring principles enabled us to elucidate the relationship between the actual presence of eyelid closure and OO-EMG activity. An interesting finding permitted by the new system was that the monkeys frequently exhibited obvious CRs even when they produced visible facial signs of drowsiness or microsleep. Indeed, the probability of observing a CR in a given trial was not influenced by whether the monkeys closed their eyelids just before CS onset, suggesting that this memory could be expressed independently of wakefulness. This work presents a novel system for cognitive assessment in monkeys that will be useful for elucidating the neural mechanisms of implicit learning in nonhuman primates.

  13. Reevaluation of the role of parallel fiber synapses in delay eyeblink conditioning in mice using Cbln1 as a tool

    OpenAIRE

    Kyoichi eEmi; Wataru eKakegawa; Eriko eMiura; Aya eIto-Ishida; Kazuhisa eKohda; Michisuke eYuzaki

    2013-01-01

    The delay eyeblink conditioning (EBC) is a cerebellum-dependent type of associative motor learning. However, the exact roles played by the various cerebellar synapses, as well as the underlying molecular mechanisms, remain to be determined. It is also unclear whether long-term potentiation (LTP) or long-term depression (LTD) at parallel fiber (PF)–Purkinje cell synapses is involved in EBC. In this study, to clarify the role of PF synapses in the delay EBC, we used mice in which a gene encodin...

  14. Reevaluation of the role of parallel fiber synapses in delay eyeblink conditioning in mice using Cbln1 as a tool.

    Science.gov (United States)

    Emi, Kyoichi; Kakegawa, Wataru; Miura, Eriko; Ito-Ishida, Aya; Kohda, Kazuhisa; Yuzaki, Michisuke

    2013-01-01

    The delay eyeblink conditioning (EBC) is a cerebellum-dependent type of associative motor learning. However, the exact roles played by the various cerebellar synapses, as well as the underlying molecular mechanisms, remain to be determined. It is also unclear whether long-term potentiation (LTP) or long-term depression (LTD) at parallel fiber (PF)-Purkinje cell (PC) synapses is involved in EBC. In this study, to clarify the role of PF synapses in the delay EBC, we used mice in which a gene encoding Cbln1 was disrupted (cbln1(-/-) mice), which display severe reduction of PF-PC synapses. We showed that delay EBC was impaired in cbln1(-/-) mice. Although PF-LTD was impaired, PF-LTP was normally induced in cbln1(-/-) mice. A single recombinant Cbln1 injection to the cerebellar cortex in vivo completely, though transiently, restored the morphology and function of PF-PC synapses and delay EBC in cbln1(-/-) mice. Interestingly, the cbln1(-/-) mice retained the memory for at least 30 days, after the Cbln1 injection's effect on PF synapses had abated. Furthermore, delay EBC memory could be extinguished even after the Cbln1 injection's effect were lost. These results indicate that intact PF-PC synapses and PF-LTD, not PF-LTP, are necessary to acquire delay EBC in mice. In contrast, extracerebellar structures or remaining PF-PC synapses in cbln1(-/-) mice may be sufficient for the expression, maintenance, and extinction of its memory trace.

  15. Reevaluation of the role of parallel fiber synapses in delay eyeblink conditioning in mice using Cbln1 as a tool

    Directory of Open Access Journals (Sweden)

    Kyoichi eEmi

    2013-11-01

    Full Text Available The delay eyeblink conditioning (EBC is a cerebellum-dependent type of associative motor learning. However, the exact roles played by the various cerebellar synapses, as well as the underlying molecular mechanisms, remain to be determined. It is also unclear whether long-term potentiation (LTP or long-term depression (LTD at parallel fiber (PF–Purkinje cell synapses is involved in EBC. In this study, to clarify the role of PF synapses in the delay EBC, we used mice in which a gene encoding Cbln1 was disrupted (cbln1–/– mice, which display severe reduction of PF–Purkinje cell synapses. We showed that delay EBC was impaired in cbln1–/– mice. Although PF-LTD was impaired, PF-LTP was normally induced in cbln1–/– mice. A single recombinant Cbln1 injection to the cerebellar cortex in vivo completely, though transiently, restored the morphology and function of PF–Purkinje cell synapses and delay EBC in cbln1–/– mice. Interestingly, the cbln1–/– mice retained the memory for at least 30 d, after the Cbln1 injection’s effect on PF synapses had abated. Furthermore, delay EBC memory could be extinguished even after the Cbln1 injection’s effect were lost. These results indicate that intact PF–Purkinje cell synapses and PF-LTD, not PF-LTP, are necessary to acquire delay EBC in mice. In contrast, extracerebellar structures or remaining PF–Purkinje cell synapses in cbln1–/– mice may be sufficient for the expression, maintenance, and extinction of its memory trace.

  16. Deep cerebellar nuclei play an important role in two-tone discrimination on delay eyeblink conditioning in C57BL/6 mice.

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    Sakamoto, Toshiro; Endo, Shogo

    2013-01-01

    Previous studies have shown that deep cerebellar nuclei (DCN)-lesioned mice develop conditioned responses (CR) on delay eyeblink conditioning when a salient tone conditioned stimulus (CS) is used, which suggests that the cerebellum potentially plays a role in more complicated cognitive functions. In the present study, we examined the role of DCN in tone frequency discrimination in the delay eyeblink-conditioning paradigm. In the first experiment, DCN-lesioned and sham-operated mice were subjected to standard simple eyeblink conditioning under low-frequency tone CS (LCS: 1 kHz, 80 dB) or high-frequency tone CS (HCS: 10 kHz, 70 dB) conditions. DCN-lesioned mice developed CR in both CS conditions as well as sham-operated mice. In the second experiment, DCN-lesioned and sham-operated mice were subjected to two-tone discrimination tasks, with LCS+ (or HCS+) paired with unconditioned stimulus (US), and HCS- (or LCS-) without US. CR% in sham-operated mice increased in LCS+ (or HCS+) trials, regardless of tone frequency of CS, but not in HCS- (or LCS-) trials. The results indicate that sham-operated mice can discriminate between LCS+ and HCS- (or HCS+ and LCS-). In contrast, DCN-lesioned mice showed high CR% in not only LCS+ (or HCS+) trials but also HCS- (or LCS-) trials. The results indicate that DCN lesions impair the discrimination between tone frequency in eyeblink conditioning. Our results suggest that the cerebellum plays a pivotal role in the discrimination of tone frequency.

  17. Deep cerebellar nuclei play an important role in two-tone discrimination on delay eyeblink conditioning in C57BL/6 mice.

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    Toshiro Sakamoto

    Full Text Available Previous studies have shown that deep cerebellar nuclei (DCN-lesioned mice develop conditioned responses (CR on delay eyeblink conditioning when a salient tone conditioned stimulus (CS is used, which suggests that the cerebellum potentially plays a role in more complicated cognitive functions. In the present study, we examined the role of DCN in tone frequency discrimination in the delay eyeblink-conditioning paradigm. In the first experiment, DCN-lesioned and sham-operated mice were subjected to standard simple eyeblink conditioning under low-frequency tone CS (LCS: 1 kHz, 80 dB or high-frequency tone CS (HCS: 10 kHz, 70 dB conditions. DCN-lesioned mice developed CR in both CS conditions as well as sham-operated mice. In the second experiment, DCN-lesioned and sham-operated mice were subjected to two-tone discrimination tasks, with LCS+ (or HCS+ paired with unconditioned stimulus (US, and HCS- (or LCS- without US. CR% in sham-operated mice increased in LCS+ (or HCS+ trials, regardless of tone frequency of CS, but not in HCS- (or LCS- trials. The results indicate that sham-operated mice can discriminate between LCS+ and HCS- (or HCS+ and LCS-. In contrast, DCN-lesioned mice showed high CR% in not only LCS+ (or HCS+ trials but also HCS- (or LCS- trials. The results indicate that DCN lesions impair the discrimination between tone frequency in eyeblink conditioning. Our results suggest that the cerebellum plays a pivotal role in the discrimination of tone frequency.

  18. Eyeblink classical conditioning differentiates normal aging from Alzheimer's disease.

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    Woodruff-Pak, D S

    2001-01-01

    Eyeblink classical conditioning is a useful paradigm for the study of the neurobiology of learning, memory, and aging, which also has application in the differential diagnosis of neurodegenerative diseases expressed in advancing age. Converging evidence from studies of eyeblink conditioning in neurological patients and brain imaging in normal adults document parallels in the neural substrates of this form of associative learning in humans and non-human mammals. Age differences in the short-delay procedure (400 ms CS-US interval) appear in middle age in humans and may be caused at least in part by cerebellar cortical changes such as loss of Purkinje cells. Whereas the hippocampus is not essential for conditioning in the delay procedure, disruption of hippocampal cholinergic neurotransmission impairs acquisition and slows the rate of learning. Alzheimer's disease (AD) profoundly disrupts the hippocampaL cholinergic system, and patients with AD consistently perform poorly in eyeblink conditioning. We hypothesize that disruption of hippocampal cholinergic pathways in AD in addition to age-associated Purkinje cell loss results in severely impaired eyeblink conditioning. The earliest pathology in AD occurs in entorhinal cortical input to hippocampus, and eyeblink conditioning may detect this early disruption before declarative learning and memory circuits become impaired. A case study is presented in which eyeblink conditioning detected impending dementia six years before changes on other screening tests indicated impairment. Because eyeblink conditioning is simple, non-threatening, and non-invasive, it may become a useful addition to test batteries designed to differentiate normal aging from mild cognitive impairment that progresses to AD and AD from other types of dementia.

  19. Central Cannabinoid Receptors Modulate Acquisition of Eyeblink Conditioning

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    Steinmetz, Adam B.; Freeman, John H.

    2010-01-01

    Delay eyeblink conditioning is established by paired presentations of a conditioned stimulus (CS) such as a tone or light, and an unconditioned stimulus (US) that elicits the blink reflex. Conditioned stimulus information is projected from the basilar pontine nuclei to the cerebellar interpositus nucleus and cortex. The cerebellar cortex,…

  20. Eyeblink classical conditioning in the preweanling lamb.

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    Johnson, Timothy B; Stanton, Mark E; Goodlett, Charles R; Cudd, Timothy A

    2008-06-01

    Classical conditioning of eyeblink responses has been one of the most important models for studying the neurobiology of learning, with many comparative, ontogenetic, and clinical applications. The current study reports the development of procedures to conduct eyeblink conditioning in preweanling lambs and demonstrates successful conditioning using these procedures. These methods will permit application of eyeblink conditioning procedures in the analysis of functional correlates of cerebellar damage in a sheep model of fetal alcohol spectrum disorders, which has significant advantages over more common laboratory rodent models. Because sheep have been widely used for studies of pathogenesis and mechanisms of injury with many different prenatal or perinatal physiological insults, eyeblink conditioning can provide a well-studied method to assess postnatal behavioral outcomes, which heretofore have not typically been pursued with ovine models of developmental insults.

  1. Children with specific language impairment are not impaired in the acquisition and retention of Pavlovian delay and trace conditioning of the eyeblink response.

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    Hardiman, Mervyn J; Hsu, Hsin-jen; Bishop, Dorothy V M

    2013-12-01

    Three converging lines of evidence have suggested that cerebellar abnormality is implicated in developmental language and literacy problems. First, some brain imaging studies have linked abnormalities in cerebellar grey matter to dyslexia and specific language impairment (SLI). Second, theoretical accounts of both dyslexia and SLI have postulated impairments of procedural learning and automatisation of skills, functions that are known to be mediated by the cerebellum. Third, motor learning has been shown to be abnormal in some studies of both disorders. We assessed the integrity of face related regions of the cerebellum using Pavlovian eyeblink conditioning in 7-11year-old children with SLI. We found no relationship between oral language skills or literacy skills with either delay or trace conditioning in the children. We conclude that this elementary form of associative learning is intact in children with impaired language or literacy development. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

  2. Effects of OEF/OIF-Related Physical and Emotional Co-Morbidities on Associative Learning: Concurrent Delay and Trace Eyeblink Classical Conditioning

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    Regina E. McGlinchey

    2014-03-01

    Full Text Available This study examined the performance of veterans and active duty personnel who served in Operation Enduring Freedom and/or Operation Iraqi Freedom (OEF/OIF on a basic associative learning task. Eighty-eight individuals participated in this study. All received a comprehensive clinical evaluation to determine the presence and severity of posttraumatic stress disorder (PTSD and traumatic brain injury (TBI. The eyeblink conditioning task was composed of randomly intermixed delay and trace conditioned stimulus (CS and unconditioned stimulus (US pairs (acquisition followed by a series of CS only trials (extinction. Results revealed that those with a clinical diagnosis of PTSD or a diagnosis of PTSD with comorbid mTBI acquired delay and trace conditioned responses (CRs to levels and at rates similar to a deployed control group, thus suggesting intact basic associative learning. Differential extinction impairment was observed in the two clinical groups. Acquisition of CRs for both delay and trace conditioning, as well as extinction of trace CRs, was associated with alcoholic behavior across all participants. These findings help characterize the learning and memory function of individuals with PTSD and mTBI from OEF/OIF and raise the alarming possibility that the use of alcohol in this group may lead to more significant cognitive dysfunction.

  3. Effects of OEF/OIF-related physical and emotional co-morbidities on associative learning: concurrent delay and trace eyeblink classical conditioning.

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    McGlinchey, Regina E; Fortier, Catherine B; Venne, Jonathan R; Maksimovskiy, Arkadiy L; Milberg, William P

    2014-03-12

    This study examined the performance of veterans and active duty personnel who served in Operation Enduring Freedom and/or Operation Iraqi Freedom (OEF/OIF) on a basic associative learning task. Eighty-eight individuals participated in this study. All received a comprehensive clinical evaluation to determine the presence and severity of posttraumatic stress disorder (PTSD) and traumatic brain injury (TBI). The eyeblink conditioning task was composed of randomly intermixed delay and trace conditioned stimulus (CS) and unconditioned stimulus (US) pairs (acquisition) followed by a series of CS only trials (extinction). Results revealed that those with a clinical diagnosis of PTSD or a diagnosis of PTSD with comorbid mTBI acquired delay and trace conditioned responses (CRs) to levels and at rates similar to a deployed control group, thus suggesting intact basic associative learning. Differential extinction impairment was observed in the two clinical groups. Acquisition of CRs for both delay and trace conditioning, as well as extinction of trace CRs, was associated with alcoholic behavior across all participants. These findings help characterize the learning and memory function of individuals with PTSD and mTBI from OEF/OIF and raise the alarming possibility that the use of alcohol in this group may lead to more significant cognitive dysfunction.

  4. Cerebellar Secretin Modulates Eyeblink Classical Conditioning

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    Fuchs, Jason R.; Robinson, Gain M.; Dean, Aaron M.; Schoenberg, Heidi E.; Williams, Michael R.; Morielli, Anthony D.; Green, John T.

    2014-01-01

    We have previously shown that intracerebellar infusion of the neuropeptide secretin enhances the acquisition phase of eyeblink conditioning (EBC). Here, we sought to test whether endogenous secretin also regulates EBC and to test whether the effect of exogenous and endogenous secretin is specific to acquisition. In Experiment 1, rats received…

  5. Classical eyeblink conditioning in Parkinson's disease.

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    Daum, I; Schugens, M M; Breitenstein, C; Topka, H; Spieker, S

    1996-11-01

    Patients with Parkinson's disease (PD) show impairments of a range of motor learning tasks, including tracking or serial reaction time task learning. Our study investigated whether such deficits would also be seen on a simple type of motor learning, classic conditioning of the eyeblink response. Medicated and unmediated patients with PD showed intact unconditioned eyeblink responses and significant learning across acquisition; the learning rates did not differ from those of healthy control subjects. The overall frequency of conditioned responses was significantly higher in the medicated patients with PD relative to control subjects, and there was also some evidence of facilitation in the unmedicated patients with PD. Conditioning of electrodermal and electrocortical responses was comparable in all groups. The findings are discussed in terms of enhanced excitability of brainstem pathways in PD and of the involvement of different neuronal circuits in different types of motor learning.

  6. Cerebellar cortical inhibition and classical eyeblink conditioning.

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    Bao, Shaowen; Chen, Lu; Kim, Jeansok J; Thompson, Richard F

    2002-02-01

    The cerebellum is considered a brain structure in which memories for learned motor responses (e.g., conditioned eyeblink responses) are stored. Within the cerebellum, however, the relative importance of the cortex and the deep nuclei in motor learning/memory is not entirely clear. In this study, we show that the cerebellar cortex exerts both basal and stimulus-activated inhibition to the deep nuclei. Sequential application of a gamma-aminobutyric acid type A receptor (GABA(A)R) agonist and a noncompetitive GABA(A)R antagonist allows selective blockade of stimulus-activated inhibition. By using the same sequential agonist and antagonist methods in behaving animals, we demonstrate that the conditioned response (CR) expression and timing are completely dissociable and involve different inhibitory inputs; although the basal inhibition modulates CR expression, the conditioned stimulus-activated inhibition is required for the proper timing of the CR. In addition, complete blockade of cerebellar deep nuclear GABA(A)Rs prevents CR acquisition. Together, these results suggest that different aspects of the memories for eyeblink CRs are encoded in the cerebellar cortex and the cerebellar deep nuclei.

  7. Contrasts in Infant Classical Eyeblink Conditioning as a Function of Premature Birth

    Science.gov (United States)

    Herbert, Jane S.; Eckerman, Carol O.; Goldstein, Ricki F.; Stanton, Mark E.

    2004-01-01

    The impact of premature birth on associative learning was evaluated using simple delay eyeblink conditioning in which a tone conditional stimulus was paired with an air puff unconditional stimulus. Fourteen preterm (28-31 weeks gestation) and 11 full-term infants completed at least 3 conditioning sessions, 1 week apart, at 5 months of age…

  8. Trace eyeblink conditioning is impaired in α7 but not in β2 nicotinic acetylcholine receptor knock-out mice

    Directory of Open Access Journals (Sweden)

    Kevin L Brown

    2010-10-01

    Full Text Available Nicotinic acetylcholine receptors (nAChRs are essentially involved in learning and memory. A neurobiologically and behaviorally well-characterized measure of learning and memory, eyeblink classical conditioning, is sensitive to disruptions in acetylcholine neurotransmission. The two most common forms of eyeblink classical conditioning – the delay and trace paradigms - differentially engage forebrain areas densely-populated with nAChRs. The present study used genetically modified mice to investigate the effects of selective nAChR subunit deletion on delay and trace eyeblink classical conditioning. α7 and β2 nAChR subunit knockout (KO mice and their wild-type littermates were trained for 10 daily sessions in a 500 ms delay or 500 ms trace eyeblink conditioning task, matched for the interstimulus interval (ISI between conditioned stimulus (CS and unconditioned stimulus (US onset. Impairments in conditioned responding were found in α7 KO mice trained in trace – but not delayeyeblink conditioning. Relative to littermate controls, β2 KO mice were unimpaired in the trace task but displayed higher levels of conditioned responding in delay eyeblink conditioning. Elevated conditioned response levels in delay-conditioned β2 KOs corresponded to elevated levels of alpha responding in this group. These findings suggest that α7 nAChRs play a role in normal acquisition of 500 ms trace eyeblink classical conditioning in mice. The prominent distribution of α7 nAChRs in the hippocampus and other forebrain regions may account for these genotype-specific acquisition effects in this hippocampus-dependent trace paradigm.

  9. The effects of two forms of physical activity on eyeblink classical conditioning.

    Science.gov (United States)

    Green, John T; Chess, Amy C; Burns, Montana; Schachinger, Kira M; Thanellou, Alexandra

    2011-05-16

    Voluntary exercise, in the form of free access to a running wheel in the home cage, has been shown to improve several forms of learning and memory. Acrobatic training, in the form of learning to traverse an elevated obstacle course, has been shown to induce markers of neural plasticity in the cerebellar cortex in rodents. In three experiments, we examined the effects of these two forms of physical activity on delay eyeblink conditioning in rats. In Experiment 1, exercising rats were given 17 days of free access to a running wheel in their home cage prior to 10 days of delay eyeblink conditioning. Rats that exercised conditioned significantly better and showed a larger reflexive eyeblink unconditioned response to the periocular stimulation unconditioned stimulus than rats that did not exercise. In Experiment 2, exercising rats were given 17 days of free access to a running wheel in their home cage prior to 10 days of explicitly unpaired stimulus presentations. Rats that exercised responded the same to tone, light, and periocular stimulation as rats that did not exercise. In Experiment 3, acrobatic training rats were given 15 days of daily training on an elevated obstacle course prior to 10 days of eyeblink conditioning. Activity control rats underwent 15 days of yoked daily running in an open field. Rats that underwent acrobatic training did not differ in eyeblink conditioning from activity control rats. The ability to measure the learned response precisely, and the well-mapped neural circuitry of eyeblink conditioning offer some advantages for the study of exercise effects on learning and memory.

  10. The Effects of Two Forms of Physical Activity on Eyeblink Classical Conditioning

    Science.gov (United States)

    Green, John T.; Chess, Amy C.; Burns, Montana; Schachinger, Kira M.; Thanellou, Alexandra

    2011-01-01

    Voluntary exercise, in the form of free access to a running wheel in the home cage, has been shown to improve several forms of learning and memory. Acrobatic training, in the form of learning to traverse an elevated obstacle course, has been shown to induce markers of neural plasticity in the cerebellar cortex in rodents. In three experiments, we examined the effects of these two forms of physical activity on delay eyeblink conditioning in rats. In Experiment 1, exercising rats were given 17 days of free access to a running wheel in their home cage prior to 10 days of delay eyeblink conditioning. Rats that exercised conditioned significantly better and showed a larger reflexive eyeblink unconditioned response to the periocular stimulation unconditioned stimulus than rats that did not exercise. In Experiment 2, exercising rats were given 17 days of free access to a running wheel in their home cage prior to 10 days of explicitly unpaired stimulus presentations. Rats that exercised responded the same to tone, light, and periocular stimulation as rats that did not exercise. In Experiment 3, acrobatic training rats were given 15 days of daily training on an elevated obstacle course prior to 10 days of eyeblink conditioning. Activity control rats underwent 15 days of yoked daily running in an open field. Rats that underwent acrobatic training did not differ in eyeblink conditioning from activity control rats. The ability to measure the learned response precisely, and the well-mapped neural circuitry of eyeblink conditioning offer some advantages for the study of exercise effects on learning and memory. PMID:21238502

  11. The involvement of the human cerebellum in eyeblink conditioning.

    Science.gov (United States)

    Gerwig, M; Kolb, F P; Timmann, D

    2007-01-01

    Besides its known importance for motor coordination, the cerebellum plays a major role in associative learning. The form of cerebellum-dependent associative learning, which has been examined in greatest detail, is classical conditioning of eyeblink responses. The much advanced knowledge of anatomical correlates, as well as cellular and molecular mechanisms involved in eyeblink conditioning in animal models are of particular importance because there is general acceptance that findings in humans parallel the animal data. The aim of the present review is to give an update of findings in humans. Emphasis is put on human lesion studies, which take advantage of the advances of high-resolution structural magnetic resonance imaging (MRI). In addition, findings of functional brain imaging in healthy human subjects are reviewed. The former helped to localize areas involved in eyeblink conditioning within the cerebellum, the latter was in particular helpful in delineating extracerebellar neural substrates, which may contribute to eyeblink conditioning. Human lesion studies support the importance of cortical areas of the ipsilateral superior cerebellum both in the acquisition and timing of conditioned eyeblink responses (CR). Furthermore, the ipsilateral cerebellar cortex seems to be also important in extinction of CRs. Cortical areas, which are important for CR acquisition, overlap with areas related to the control of the unconditioned eyeblink response. Likewise, cortical lesions are followed by increased amplitudes of unconditioned eyeblinks. These findings are in good accordance with the animal literature. Knowledge about contributions of the cerebellar nuclei in humans, however, is sparse. Due to methodological limitations both of human lesion and functional MRI studies, at present no clear conclusions can be drawn on the relative contributions of the cerebellar cortex and nuclei.

  12. Classical eyeblink conditioning using electrical stimulation of caudal mPFC as conditioned stimulus is dependent on cerebellar interpositus nucleus in guinea pigs

    Institute of Scientific and Technical Information of China (English)

    Guang-yan WU; Juan YAO; Zheng-li FAN; Lang-qian ZHANG; Xuan LI; Chuang-dong ZHAO; Zhen-hua ZHOU; Jian-feng SUI

    2012-01-01

    Aim:To determine whether electrical stimulation of caudal medial prefrontal cortex (mPFC) as conditioned stimulus (CS) paired with airpuff unconditioned stimulus (US) was sufficient for establishing eyeblink conditioning in guinea pigs,and whether it was dependent on cerebellar interpositus nucleus.Methods:Thirty adult guinea pigs were divided into 3 conditioned groups,and trained on the delay eyeblink conditioning,short-trace eyeblink conditioning,and long-trace eyeblink conditioning paradigms,respectively,in which electrical stimulation of the right caudal mPFC was used as CS and paired with corneal airpuff US.A pseudo conditioned group of another 10 adult guinea pigs was given unpaired caudal mPFC electrical stimulation and the US.Muscimol (1 μg in 1 μL saline) and saline (1 μL) were infused into the cerebellar interpositus nucleus of the animals through the infusion cannula on d 11 and 12,respectively.Results:The 3 eyeblink conditioning paradigms have been successfully established in guinea pigs.The animals acquired the delay and short-trace conditioned responses more rapidly than long-trace conditioned responses.Muscimol infusion into the cerebellar interpositus nucleus markedly impaired the expression of the 3 eyeblink conditioned responses.Conclusion:Electrical stimulation of caudal mPFC is effective CS for establishing eyeblink conditioning in guinea pigs,and it is dependent on the cerebellar interpositus nucleus.

  13. Eyeblink Conditioning: A Non-Invasive Biomarker for Neurodevelopmental Disorders

    Science.gov (United States)

    Reeb-Sutherland, Bethany C.; Fox, Nathan A.

    2015-01-01

    Eyeblink conditioning (EBC) is a classical conditioning paradigm typically used to study the underlying neural processes of learning and memory. EBC has a well-defined neural circuitry, is non-invasive, and can be employed in human infants shortly after birth making it an ideal tool to use in both developing and special populations. In addition,…

  14. Accelerated trace eyeblink conditioning after cortisol IV-infusion.

    Science.gov (United States)

    Kuehl, Linn K; Lass-Hennemann, Johanna; Richter, Steffen; Blumenthal, Terry D; Oitzl, Melly; Schachinger, Hartmut

    2010-11-01

    Impairing effects of cortisol on learning performance have been shown in human trace eyeblink conditioning. As the effect is observed from 30 min to hours after administration, a genomic action of cortisol is assumed. Here we report rapid cortisol effects that were observed during the first 10 min after cortisol administration in humans. Young healthy males (n=24) received the cortisol synthesis inhibitor metyrapone (1.5 g per os) to avoid interference of the endogenous pulsatile secretion of cortisol. Next, 2mg cortisol or placebo was infused intravenously, immediately before the trace conditioning task. The probability of the conditioned eyeblink responses was assessed electromyographically during the trace eyeblink conditioning task (unconditioned stimulus: corneal air puff, 10 psi, 50 ms; conditioned stimulus: binaural pure tone, 7 dB, 1000 Hz, 400 ms; empty interval between CS and US: 550 ms). Cortisol resulted in a faster increase of conditioning (p=.02), reaching a comparable level to placebo later on. This result extends the well-known effects of stress on the quality and amount of learning by showing that cortisol also affects the speed of learning. We propose that cortisol accelerates trace eyeblink conditioning via a fast, non-genomic mechanism. This fast action of cortisol is part of the adaptive strategy during the early stress response.

  15. Normal eyeblink classical conditioning in patients with fixed dystonia

    NARCIS (Netherlands)

    Janssen, S.; Veugen, L.C.; Hoffland, B.S.; Kassavetis, P.; Rooijen, D.E. van; Stegeman, D.F.; Edwards, Mark J.; Hilten, J.J. van; Warrenburg, B.P.C. van de

    2014-01-01

    Fixed dystonia without evidence of basal ganglia lesions or neurodegeneration typically affects young women following minor peripheral trauma. We use eyeblink classical conditioning (EBCC) to study whether cerebellar functioning is abnormal in patients with fixed dystonia, since this is part of the

  16. Cerebellum lesion impairs eyeblink-like classical conditioning in goldfish.

    Science.gov (United States)

    Gómez, A; Durán, E; Salas, C; Rodríguez, F

    2010-03-10

    The cerebellum of mammals is an essential component of the neural circuitry underlying classical conditioning of eyeblink and other discrete responses. Although the neuroanatomical organization of the cerebellum is notably well conserved in vertebrates, little is actually known about the cerebellar learning functions in nonmammal vertebrate groups. In this work we studied whether the cerebellum of teleost fish plays a critical role in the classical conditioning of a motor response. In Experiment 1, we classically conditioned goldfish in a procedure analogous to the eyeblink conditioning paradigm commonly used in mammals. Goldfish were able to learn to express an eyeblink-like conditioned response to a predictive light (conditioned stimulus) that was paired with a mild electric shock (unconditioned stimulus). The application of unpaired and extinction control procedures demonstrated that also in teleosts the learning of this motor response depends on associative rules. In Experiment 2 we studied whether classical conditioning of this response is critically dependent on the cerebellum and independent of telencephalic structures as occurs in mammals. Cerebellum lesion prevented the acquisition of the eyeblink-like conditioned response whereas telencephalon ablation did not impair the learning of this response. No deficit was observed following lesions in the performance of the unconditioned response or in the percentage of spontaneous responses. These results suggest that cerebellum ablation in goldfish affects a critical component of the circuitry necessary for the acquisition of the conditioned response but does not interfere with the ability of the animal to perform the response itself. The striking similarity in the role of cerebellum in classical conditioning of a motor response between teleost fish and mammals suggests that this learning function of the cerebellum could be a primitive feature of the vertebrate brain that has been conserved through evolution.

  17. Shortened Conditioned Eyeblink Response Latency in Male but not Female Wistar-Kyoto Hyperactive Rats

    Science.gov (United States)

    Thanellou, Alexandra; Schachinger, Kira M.; Green, John T.

    2014-01-01

    Reductions in the volume of the cerebellum and impairments in cerebellar-dependent eyeblink conditioning have been observed in attention-deficit/hyperactivity disorder (ADHD). Recently, it was reported that subjects with ADHD as well as male spontaneously hypertensive rats (SHR), a strain that is frequently employed as an animal model in the study of ADHD, exhibit a parallel pattern of timing deficits in eyeblink conditioning. One criticism that has been posed regarding the validity of the SHR strain as an animal model for the study of ADHD is that SHRs are not only hyperactive but also hypertensive. It is conceivable that many of the behavioral characteristics seen in SHRs that seem to parallel the behavioral symptoms of ADHD are not solely due to hyperactivity but instead are the net outcome of the interaction between hyperactivity and hypertension. We used Wistar-Kyoto Hyperactive (WKHA) and Wistar-Kyoto Hypertensive (WKHT) rats (males and females), strains generated from recombinant inbreeding of SHRs and their progenitor strain, Wistar-Kyoto (WKY) rats, to compare eyeblink conditioning in strains that are exclusively hyperactive or hypertensive. We used a long-delay eyeblink conditioning task in which a tone conditioned stimulus was paired with a periorbital stimulation unconditioned stimulus (750-ms delay paradigm). Our results showed that WKHA and WKHT rats exhibited similar rates of conditioned response (CR) acquisition. However, WKHA males displayed shortened CR latencies (early onset and peak latency) in comparison to WKHT males. In contrast, female WKHAs and WKHTs did not differ. In subsequent extinction training, WKHA rats extinguished at similar rates in comparison to WKHT rats. The current results support the hypothesis of a relationship between cerebellar abnormalities and ADHD in an animal model of ADHD-like symptoms that does not also exhibit hypertension, and suggest that cerebellar-related timing deficits are specific to males. PMID:19485572

  18. Cortical spreading depression and involvement of the motor cortex, auditory cortex, and cerebellum in eyeblink classical conditioning of the rabbit.

    Science.gov (United States)

    Case, Gilbert R; Lavond, David G; Thompson, Richard F

    2002-09-01

    The interrelationships of cerebellar and cerebral neural circuits in the eyeblink paradigm were explored with the controlled application of cortical spreading depression (CSD) and lidocaine in the New Zealand albino rabbit. The initial research focus was directed toward the involvement of the motor cortex in the conditioned eyeblink response. However, CSD timing and triangulation results indicate that other areas in the cerebral cortex, particularly the auditory cortex (acoustic conditioned stimulus), appear to be critical for the CSD effect on the eyeblink response. In summary: (1) CSD can be elicited, monitored, and timed and its side effects controlled in 97% of awake rabbits in the right and/or left cerebral hemisphere(s) during eyeblink conditioning. (2) The motor cortex appears to play little or no part in classical conditioning of the eyeblink in the rabbit in the delay paradigm. (3) Inactivating the auditory cortex with CSD or lidocaine temporarily impairs the conditioned response during the first 5 to 15 days of training, but has little effect past that point.

  19. Effects of Paradigm and Inter-Stimulus Interval on Age Differences in Eyeblink Classical Conditioning in Rabbits

    Science.gov (United States)

    Woodruff-Pak, Diana S.; Seta, Susan E.; Roker, LaToya A.; Lehr, Melissa A.

    2007-01-01

    The aim of this study was to examine parameters affecting age differences in eyeblink classical conditioning in a large sample of young and middle-aged rabbits. A total of 122 rabbits of mean ages of 4 or 26 mo were tested at inter-stimulus intervals (ISIs) of 600 or 750 msec in the delay or trace paradigms. Paradigm affected both age groups…

  20. Facilitated acquisition of eyeblink conditioning in those vulnerable to anxiety disorders

    Directory of Open Access Journals (Sweden)

    Meghan Davis Caulfield

    2013-07-01

    Full Text Available Behavioral inhibition (BI increases vulnerability to develop anxiety disorders and is typified by avoidance and withdrawal from novel objects, people, and situations. The present study considered the relationship between behavioral inhibition and temperamental risk factors, such as trait anxiety and acquisition rate of a classically conditioned eyeblink response. 174 healthy undergraduate students (mean age 20.3 years, 71.8% female were given the State-Trait Anxiety Inventory and a battery of self-report measures of behavioral inhibition consisting of the Adult and Retrospective Measures of Behavioural Inhibition (AMBI/RMBI and the Concurrent and Retrospective Self Report of Inhibition (CSRI/RSRI. Participants then underwent standard delay classical eyeblink conditioning consisting of 45 trials with a 500-ms CS overlapping and co-terminating with a 10-ms airpuff US. Individuals with higher scores on the AMBI and Trait Anxiety Inventory, but not the other measures, showed faster acquisition of a conditioned eyeblink response than individuals with lower scores. Results support a relationship between facilitated acquisition of inter-stimulus relationships and risk for anxiety, and suggest that some measures assessing anxiety vulnerability better capture this relationship than others.

  1. Extinction, Reacquisition, and Rapid Forgetting of Eyeblink Conditioning in Developing Rats

    Science.gov (United States)

    Brown, Kevin L.; Freeman, John H.

    2014-01-01

    Eyeblink conditioning is a well-established model for studying the developmental neurobiology of associative learning and memory. However, age differences in extinction and subsequent reacquisition have yet to be studied using this model. The present study examined extinction and reacquisition of eyeblink conditioning in developing rats. In…

  2. Extinction, Reacquisition, and Rapid Forgetting of Eyeblink Conditioning in Developing Rats

    Science.gov (United States)

    Brown, Kevin L.; Freeman, John H.

    2014-01-01

    Eyeblink conditioning is a well-established model for studying the developmental neurobiology of associative learning and memory. However, age differences in extinction and subsequent reacquisition have yet to be studied using this model. The present study examined extinction and reacquisition of eyeblink conditioning in developing rats. In…

  3. Bilateral nature of the conditioned eyeblink response in the rabbit: behavioral characteristics and potential mechanisms.

    Science.gov (United States)

    Lee, Taekwan; Kim, Jeansok J; Wagner, Allan R

    2008-12-01

    In Pavlovian eyeblink conditioning, the conditioned response (CR) is highly lateralized to the eye to which the unconditioned stimulus (US) has been directed. However, the initial conditioning of one eye can facilitate subsequent conditioning of the other eye, a phenomenon known as the intereye transfer (IET) effect. Because a conditioned emotional response (CER), as well as the eyeblink CR, is acquired during eyeblink conditioning and influences the development of the CR, the CER acquired in initial training can plausibly account for the IET effect. To evaluate this possibility, the present study utilized previously determined eyeblink conditioning procedures that effectively decouple the degree of CER and CR development to investigate the IET effect. In each of 3 experiments rabbits were initially trained with comparison procedures that differentially favored the development of the eyeblink CR or the CER, prior to a shift of the US to the alternate eye. The observed differences in the IET suggest that the effect depends largely on the specific development of eyeblink CRs rather than the CER. The neurobiological implications of this apparent bilaterality of the eyeblink CR are discussed.

  4. Eyeblink conditioning: a non-invasive biomarker for neurodevelopmental disorders.

    Science.gov (United States)

    Reeb-Sutherland, Bethany C; Fox, Nathan A

    2015-02-01

    Eyeblink conditioning (EBC) is a classical conditioning paradigm typically used to study the underlying neural processes of learning and memory. EBC has a well-defined neural circuitry, is non-invasive, and can be employed in human infants shortly after birth making it an ideal tool to use in both developing and special populations. In addition, abnormalities in the cerebellum, a region of the brain highly involved in EBC, have been implicated in a number of neurodevelopmental disorders including autism spectrum disorders (ASDs). In the current paper, we review studies that have employed EBC as a biomarker for several neurodevelopmental disorders including fetal alcohol syndrome, Down syndrome, fragile X syndrome, attention deficit/hyperactivity disorder, dyslexia, specific language impairment, and schizophrenia. In addition, we discuss the benefits of using such a tool in individuals with ASD.

  5. Project DyAdd: classical eyeblink conditioning in adults with dyslexia and ADHD.

    Science.gov (United States)

    Laasonen, Marja; Kauppinen, Jenni; Leppämäki, Sami; Tani, Pekka; Harno, Hanna; Hokkanen, Laura; Wikgren, Jan

    2012-11-01

    In this study of the project DyAdd (Adult Dyslexia and Attention Deficit Disorder in Finland), classical eyeblink conditioning (EBC) was investigated in both delay and trace paradigms in adults (18-55 years) with dyslexia (n = 37), attention deficit-hyperactivity disorder (ADHD; n = 21), their comorbid combination (n = 8), and healthy controls (n = 35). In addition, the profiles of three participants with a rare autosomal dominant cerebellar disease were assessed (episodic ataxia type 2, EA-2). We found that participants with dyslexia were overall slower learners than controls in eyeblink conditioning. Further, they were the only group that had a reduced number of CRs in mediotemporal-dependent trace paradigm compared to the more cerebellum-dependent delay paradigm. Second, ADHD was found to be related to larger CR amplitude. Third, those with a comorbid condition learned faster and manifested CRs that were not well timed. Fourth, the cerebellar patients showed nearly no conditioning at all. Correlations between EBC and various neuropsychological domains (phonological processing, reading, spelling, arithmetic, executive functions, attention, and fine motor control) over all participants resulted in significant relations only for the delay paradigm: Increased amount of reading errors related with later peak latency and increased amount of self-corrections in fine motor control related with larger response magnitude. Within those who conditioned, relations emerged only for the trace paradigm: better spelling was related to larger response magnitude. These results do not lend support to the cerebellar hypothesis of dyslexia. On the contrary, dyslexia in its pure form seems to be related to a relative dysfunction of a larger hippocampal-cerebellar network. Further, larger responses in the ADHD group are suggested to result from their lowered responding threshold.

  6. The effects of ethanol on the developing cerebellum and eyeblink classical conditioning.

    Science.gov (United States)

    Green, John T

    2004-01-01

    In rats, developmental ethanol exposure has been used to model the central nervous system deficits associated with human fetal alcohol syndrome. Binge-like ethanol exposure of neonatal rats depletes cells in the cerebellum, including Purkinje cells, granule cells, and deep nuclear cells, and produces deficits in simple tests of motor coordination. However, the extent to which anatomical damage is related to behavioral deficits has been difficult to estimate. Eyeblink classical conditioning is known to engage a discrete brain stem-cerebellar circuit, making it an ideal test of cerebellar functional integrity after developmental ethanol exposure. Eyeblink conditioning is a simple form of motor learning in which a neutral stimulus (such as a tone) comes to elicit an eyeblink when repeatedly paired with a stimulus that evokes an eyeblink prior to training (such as mild periorbital stimulation). In eyeblink conditioning, one of the deep cerebellar nuclei, the interpositus nucleus, as well as specific Purkinje cell populations, are sites of convergence for tone conditioned stimulus and somatosensory unconditioned stimulus information, and, together with brain stem nuclei, provide the necessary and sufficient substrate for the learned response. A series of studies have shown that eyeblink conditioning is impaired in both weanling and adult rats given binge-like exposure to ethanol as neonates. In addition, interpositus nucleus neurons from ethanol-exposed rats showed impaired activation during eyeblink conditioning. These deficits are accompanied by a permanent reduction In the deep cerebellar nuclear cell population. Because particular cerebellar cell populations are utilized in well-defined ways during eyeblink conditioning, conclusions regarding the underlying neural substrates of behavioral change after developmental ethanol exposure are greatly strengthened.

  7. Savings and extinction of conditioned eyeblink responses in fragile X syndrome

    DEFF Research Database (Denmark)

    Smit, A E; van der Geest, J N; Vellema, M

    2008-01-01

    with FRAXA. In the present behavioral study, long-term effects of deficiency of FMRP were investigated by examining the acquisition, savings and extinction of delay eyeblink conditioning in male individuals with FRAXA. In the acquisition experiment, subjects with FRAXA displayed a significantly poor...... performance compared with controls. In the savings experiment performed at least 6 months later, subjects with FRAXA and controls showed similar levels of savings of conditioned responses. Subsequently, extinction was faster in subjects with FRAXA than in controls. These findings confirm that absence...... of the FMRP affects cerebellar motor learning. The normal performance in the savings experiment and aberrant performance in the acquisition and extinction experiments of individuals with FRAXA suggest that different mechanisms underlie acquisition, savings and extinction of cerebellar motor learning....

  8. Eyeblink Classical Conditioning in Alcoholism and Fetal Alcohol Spectrum Disorders.

    Science.gov (United States)

    Cheng, Dominic T; Jacobson, Sandra W; Jacobson, Joseph L; Molteno, Christopher D; Stanton, Mark E; Desmond, John E

    2015-01-01

    Alcoholism is a debilitating disorder that can take a significant toll on health and professional and personal relationships. Excessive alcohol consumption can have a serious impact on both drinkers and developing fetuses, leading to long-term learning impairments. Decades of research in laboratory animals and humans have demonstrated the value of eyeblink classical conditioning (EBC) as a well-characterized model system to study the neural mechanisms underlying associative learning. Behavioral EBC studies in adults with alcohol use disorders and in children with fetal alcohol spectrum disorders report a clear learning deficit in these two patient populations, suggesting alcohol-related damage to the cerebellum and associated structures. Insight into the neural mechanisms underlying these learning impairments has largely stemmed from laboratory animal studies. In this mini-review, we present and discuss exemplary animal findings and data from patient and neuroimaging studies. An improved understanding of the neural mechanisms underlying learning deficits in EBC related to alcoholism and prenatal alcohol exposure has the potential to advance the diagnoses, treatment, and prevention of these and other pediatric and adult disorders.

  9. Cerebellar tDCS Effects on Conditioned Eyeblinks using Different Electrode Placements and Stimulation Protocols

    Science.gov (United States)

    Beyer, Linda; Batsikadze, Giorgi; Timmann, Dagmar; Gerwig, Marcus

    2017-01-01

    There is good evidence that the human cerebellum is involved in the acquisition and timing of classically conditioned eyeblink responses (CRs). Animal studies suggest that the cerebellum is also important in CR extinction and savings. Cerebellar transcranial direct current stimulation (tDCS) was reported to modulate CR acquisition and timing in a polarity dependent manner. To extent previous findings three experiments were conducted using standard delay eyeblink conditioning. In a between-group design, effects of tDCS were assessed with stimulation over the right cerebellar hemisphere ipsilaterally to the unconditioned stimulus (US). An extracephalic reference electrode was used in Experiment 1 and a cephalic reference in Experiment 2. In both parts the influence on unconditioned eyeblink responses (UR) was investigated by starting stimulation in the second half of the pseudoconditioning phase lasting throughout the first half of paired trials. In a third experiment, effects of cerebellar tDCS during 40 extinction trials were assessed on extinction and reacquisition on the next day. In each experiment, 30 subjects received anodal, cathodal or sham stimulation in a double-blinded fashion. Using the extracephalic reference electrode, no significant effects on CR incidences comparing stimulation groups were observed. Using the cephalic reference anodal as well as cathodal cerebellar tDCS increased CR acquisition compared to sham only on a trend level. Analysis of timing parameters did not reveal significant effects on CR onset and peaktime latencies nor on UR timing. In the third experiment, cerebellar tDCS during extinction trials had no significant effect on extinction and savings on the next day. The present study did not reveal clear polarity dependent effects of cerebellar tDCS on CR acquisition and timing as previously described. Weaker effects may be explained by start of tDCS before the learning phase i.e., offline, individual thresholds and current flow based

  10. Cerebellar tDCS Effects on Conditioned Eyeblinks using Different Electrode Placements and Stimulation Protocols.

    Science.gov (United States)

    Beyer, Linda; Batsikadze, Giorgi; Timmann, Dagmar; Gerwig, Marcus

    2017-01-01

    There is good evidence that the human cerebellum is involved in the acquisition and timing of classically conditioned eyeblink responses (CRs). Animal studies suggest that the cerebellum is also important in CR extinction and savings. Cerebellar transcranial direct current stimulation (tDCS) was reported to modulate CR acquisition and timing in a polarity dependent manner. To extent previous findings three experiments were conducted using standard delay eyeblink conditioning. In a between-group design, effects of tDCS were assessed with stimulation over the right cerebellar hemisphere ipsilaterally to the unconditioned stimulus (US). An extracephalic reference electrode was used in Experiment 1 and a cephalic reference in Experiment 2. In both parts the influence on unconditioned eyeblink responses (UR) was investigated by starting stimulation in the second half of the pseudoconditioning phase lasting throughout the first half of paired trials. In a third experiment, effects of cerebellar tDCS during 40 extinction trials were assessed on extinction and reacquisition on the next day. In each experiment, 30 subjects received anodal, cathodal or sham stimulation in a double-blinded fashion. Using the extracephalic reference electrode, no significant effects on CR incidences comparing stimulation groups were observed. Using the cephalic reference anodal as well as cathodal cerebellar tDCS increased CR acquisition compared to sham only on a trend level. Analysis of timing parameters did not reveal significant effects on CR onset and peaktime latencies nor on UR timing. In the third experiment, cerebellar tDCS during extinction trials had no significant effect on extinction and savings on the next day. The present study did not reveal clear polarity dependent effects of cerebellar tDCS on CR acquisition and timing as previously described. Weaker effects may be explained by start of tDCS before the learning phase i.e., offline, individual thresholds and current flow based

  11. Whisker-signaled Eyeblink Classical Conditioning in Head-fixed Mice.

    Science.gov (United States)

    Lin, Carmen; Disterhoft, John; Weiss, Craig

    2016-03-30

    Eyeblink conditioning is a common paradigm for investigating the neural mechanisms underlying learning and memory. To better utilize the extensive repertoire of scientific techniques available to study learning and memory at the cellular level, it is ideal to have a stable cranial platform. Because mice do not readily tolerate restraint, they are usually trained while moving about freely in a chamber. Conditioned stimulus (CS) and unconditioned stimulus (US) information are delivered and eyeblink responses recorded via a tether connected to the mouse's head. In the head-fixed apparatus presented here, mice are allowed to run as they desire while their heads are secured to facilitate experimentation. Reliable conditioning of the eyeblink response is obtained with this training apparatus, which allows for the delivery of whisker stimulation as the CS, a periorbital electrical shock as the US, and analysis of electromyographic (EMG) activity from the eyelid to detect blink responses.

  12. Hippocampal Non-Theta-Contingent Eyeblink Classical Conditioning: A Model System for Neurobiological Dysfunction.

    Science.gov (United States)

    Cicchese, Joseph J; Berry, Stephen D

    2016-01-01

    Typical information processing is thought to depend on the integrity of neurobiological oscillations that may underlie coordination and timing of cells and assemblies within and between structures. The 3-7 Hz bandwidth of hippocampal theta rhythm is associated with cognitive processes essential to learning and depends on the integrity of cholinergic, GABAergic, and glutamatergic forebrain systems. Since several significant psychiatric disorders appear to result from dysfunction of medial temporal lobe (MTL) neurochemical systems, preclinical studies on animal models may be an important step in defining and treating such syndromes. Many studies have shown that the amount of hippocampal theta in the rabbit strongly predicts the acquisition rate of classical eyeblink conditioning and that impairment of this system substantially slows the rate of learning and attainment of asymptotic performance. Our lab has developed a brain-computer interface that makes eyeblink training trials contingent upon the explicit presence or absence of hippocampal theta. The behavioral benefit of theta-contingent training has been demonstrated in both delay and trace forms of the paradigm with a two- to fourfold increase in learning speed over non-theta states. The non-theta behavioral impairment is accompanied by disruption of the amplitude and synchrony of hippocampal local field potentials, multiple-unit excitation, and single-unit response patterns dependent on theta state. Our findings indicate a significant electrophysiological and behavioral impact of the pretrial state of the hippocampus that suggests an important role for this MTL system in associative learning and a significant deleterious impact in the absence of theta. Here, we focus on the impairments in the non-theta state, integrate them into current models of psychiatric disorders, and suggest how improvement in our understanding of neurobiological oscillations is critical for theories and treatment of psychiatric

  13. Intra-cerebellar infusion of the protein kinase Mzeta (PKMζ) inhibitor ZIP disrupts eyeblink classical conditioning

    Science.gov (United States)

    Chihabi, Kutibh; Morielli, Anthony D.; Green, John T.

    2016-01-01

    PKM-ζ, a constitutively active N-terminal truncated form of PKC-ζ, has long been implicated in a cellular correlate of learning, long-term potentiation (LTP). Inhibition of PKM-ζ with Zeta-inhibitory peptide (ZIP) has been shown in many brain structures to disrupt maintenance of AMPA receptors, irreversibly disrupting numerous forms of learning and memory that have been maintained for weeks. Delay eyeblink conditioning (EBC) is an established model for the assessment of cerebellar learning; here, we show that PKC-ζ and PKM-ζ are highly expressed in the cerebellar cortex, with highest expression found in Purkinje cell (PC) nuclei. Despite being highly expressed in the cerebellar cortex, no studies have examined how regulation of cerebellar PKM-ζ may affect cerebellar-dependent learning and memory. Given its disruption of learning in other brain structures, we hypothesized that ZIP would also disrupt delay EBC. We have shown that infusion of ZIP into the lobulus simplex of the rat cerebellar cortex can indeed significantly disrupt delay EBC. PMID:26949968

  14. Pontine Stimulation Overcomes Developmental Limitations in the Neural Mechanisms of Eyeblink Conditioning

    Science.gov (United States)

    Freeman, John H., Jr; Rabinak, Christine A.; Campolattaro, Matthew M.

    2005-01-01

    Pontine neuronal activation during auditory stimuli increases ontogenetically between postnatal days (P) P17 and P24 in rats. Pontine neurons are an essential component of the conditioned stimulus (CS) pathway for eyeblink conditioning, providing mossy fiber input to the cerebellum. Here we examined whether the developmental limitation in pontine…

  15. Pretrial Hippocampal ?-State Differentiates Single-Unit Response Profiles during Rabbit Trace Eyeblink Conditioning

    Science.gov (United States)

    Cicchese, Joseph J.; Darling, Ryan D.; Berry, Stephen D.

    2015-01-01

    Eyeblink conditioning given in the explicit presence of hippocampal ? results in accelerated learning and enhanced multiple-unit responses, with slower learning and suppression of unit activity under non-? conditions. Recordings from putative pyramidal cells during ?-contingent training show that pretrial ?-state is linked to the probability of…

  16. Associative Plasticity in the Medial Auditory Thalamus and Cerebellar Interpositus Nucleus During Eyeblink Conditioning

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    Halverson, Hunter E.; Lee, Inah; Freeman, John H.

    2010-01-01

    Eyeblink conditioning, a type of associative motor learning, requires the cerebellum. The medial auditory thalamus is a necessary source of stimulus input to the cerebellum during auditory eyeblink conditioning. Nothing is currently known about interactions between the thalamus and cerebellum during associative learning. In the current study, neuronal activity was recorded in the cerebellar interpositus nucleus and medial auditory thalamus simultaneously from multiple tetrodes during auditory eyeblink conditioning to examine the relative timing of learning-related plasticity within these interconnected areas. Learning-related changes in neuronal activity correlated with the eyeblink conditioned response were evident in the cerebellum before the medial auditory thalamus over the course of training and within conditioning trials, suggesting that thalamic plasticity may be driven by cerebellar feedback. Short-latency plasticity developed in the thalamus during the first conditioning session and may reflect attention to the conditioned stimulus. Extinction training resulted in a decrease in learning-related activity in both structures and an increase in inhibition within the cerebellum. A feedback projection from the cerebellar nuclei to the medial auditory thalamus was identified, which may play a role in learning by facilitating stimulus input to the cerebellum via the thalamo-pontine projection. PMID:20592200

  17. Cholinergic Septo-Hippocampal Innervation Is Required for Trace Eyeblink Classical Conditioning

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    Fontan-Lozano, Angela; Troncoso, Julieta; Munera, Alejandro; Carrion, Angel Manuel; Delgado-Garcia, Jose Maria

    2005-01-01

    We studied the effects of a selective lesion in rats, with 192-IgG-saporin, of the cholinergic neurons located in the medial septum/diagonal band (MSDB) complex on the acquisition of classical and instrumental conditioning paradigms. The MSDB lesion induced a marked deficit in the acquisition, but not in the retrieval, of eyeblink classical…

  18. γIsoform-Selective Changes in PKC Immunoreactivity after Trace Eyeblink Conditioning in the Rabbit Hippocampus

    NARCIS (Netherlands)

    Zee, E.A. van der; Kronforst-Collins, M.A.; Maizels, E.T.; Hunzicker-Dunn, M.; Disterhoft, J.F.

    1997-01-01

    An immunocytochemical examination of the rabbit hippocampus was done to determine which of the Ca2+-dependent protein kinase C (PKC) isoforms (PKCα, -βI, -βII, or -γ) are involved in associative learning. The hippocampally dependent trace eyeblink conditioning task was used for behavioral training,

  19. Cholinergic Septo-Hippocampal Innervation Is Required for Trace Eyeblink Classical Conditioning

    Science.gov (United States)

    Fontan-Lozano, Angela; Troncoso, Julieta; Munera, Alejandro; Carrion, Angel Manuel; Delgado-Garcia, Jose Maria

    2005-01-01

    We studied the effects of a selective lesion in rats, with 192-IgG-saporin, of the cholinergic neurons located in the medial septum/diagonal band (MSDB) complex on the acquisition of classical and instrumental conditioning paradigms. The MSDB lesion induced a marked deficit in the acquisition, but not in the retrieval, of eyeblink classical…

  20. Pretrial Functional Connectivity Differentiates Behavioral Outcomes during Trace Eyeblink Conditioning in the Rabbit

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    Schroeder, Matthew P.; Weiss, Craig; Procissi, Daniel; Wang, Lei; Disterhoft, John F.

    2016-01-01

    Fluctuations in neural activity can produce states that facilitate and accelerate task-related performance. Acquisition of trace eyeblink conditioning (tEBC) in the rabbit is enhanced when trials are contingent on optimal pretrial activity in the hippocampus. Other regions which are essential for whisker-signaled tEBC, such as the cerebellar…

  1. Perirhinal and Postrhinal, but Not Lateral Entorhinal, Cortices Are Essential for Acquisition of Trace Eyeblink Conditioning

    Science.gov (United States)

    Suter, Eugenie E.; Weiss, Craig; Disterhoft, John F.

    2013-01-01

    The acquisition of temporal associative tasks such as trace eyeblink conditioning is hippocampus-dependent, while consolidated performance is not. The parahippocampal region mediates much of the input and output of the hippocampus, and perirhinal (PER) and entorhinal (EC) cortices support persistent spiking, a possible mediator of temporal…

  2. Spontaneous Recovery But Not Reinstatement of the Extinguished Conditioned Eyeblink Response in the Rat

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    Thanellou, Alexandra; Green, John T.

    2011-01-01

    Reinstatement, the return of an extinguished conditioned response (CR) after reexposure to the unconditioned stimulus (US), and spontaneous recovery, the return of an extinguished CR with the passage of time, are two of four well-established phenomena which demonstrate that extinction does not erase the conditioned stimulus (CS)-US association. However, reinstatement of extinguished eyeblink CRs has never been demonstrated and spontaneous recovery of extinguished eyeblink CRs has not been systematically demonstrated in rodent eyeblink conditioning. In Experiment 1, US reexposure was administered 24 hours prior to a reinstatement test. In Experiment 2, US reexposure was administered 5 min prior to a reinstatement test. In Experiment 3, a long, discrete cue (a houselight), present in all phases of training and testing, served as a context within which each trial occurred to maximize context processing, which in other preparations has been shown to be required for reinstatement. In Experiment 4, an additional group was included that received footshock exposure, rather than US reexposure, between extinction and test, and contextual freezing was measured prior to test. Spontaneous recovery was robust in Experiments 3 and 4. In Experiment 4, context freezing was strong in a group given footshock exposure but not in a group given eyeshock US reexposure. There was no reinstatement observed in any experiment. With stimulus conditions that produce eyeblink conditioning and research designs that produce reinstatement in other forms of classical conditioning, we observed spontaneous recovery but not reinstatement of extinguished eyeblink CRs. This suggests that reinstatement, but not spontaneous recovery, is a preparation- or substrate-dependent phenomenon. PMID:21517145

  3. Autonomic and eyeblink conditioning are closely related to contingency awareness: reply to Wiens and Ohman (2002) and Manns et al. (2002).

    Science.gov (United States)

    Shanks, David R; Lovibond, Peter F

    2002-01-01

    S. Wiens and A. Ohman (2002) disputed the conclusion that Pavlovian conditioning is strongly related to contingency awareness (P. F. Lovibond & D. R. Shanks, 2002) on the basis that an inappropriate definition of awareness was used. J. R. Manns, R. E. Clark, and L. R. Squire (2002) contended that delay eyeblink conditioning is independent of awareness. The authors of the present article consider these arguments, highlight several problems in the new studies described by the commentators, and conclude that there is still little evidence for unconscious conditioning in either subliminal autonomic conditioning or eyeblink conditioning. The most parsimonious account of existing data is that a single learning process gives rise to both awareness and conditioned responding. Further progress in evaluating the possibility of unconscious conditioning would be facilitated by the development of more completely specified and testable dual-process models.

  4. Investigating the Role of Hippocampal BDNF in Anxiety Vulnerability Using Classical Eyeblink Conditioning.

    Science.gov (United States)

    Janke, Kellie L; Cominski, Tara P; Kuzhikandathil, Eldo V; Servatius, Richard J; Pang, Kevin C H

    2015-01-01

    Dysregulation of brain-derived neurotrophic factor (BDNF), behavioral inhibition temperament (BI), and small hippocampal volume have been linked to anxiety disorders. Individuals with BI show facilitated acquisition of the classically conditioned eyeblink response (CCER) as compared to non-BI individuals, and a similar pattern is seen in an animal model of BI, the Wistar-Kyoto (WKY) rat. The present study examined the role of hippocampal BDNF in the facilitated delay CCER of WKY rats. Consistent with earlier work, acquisition was facilitated in WKY rats compared to the Sprague Dawley (SD) rats. Facilitated acquisition was associated with increased BDNF, TrkB, and Arc mRNA in the dentate gyrus of SD rats, but learning-induced increases in BDNF and Arc mRNA were significantly smaller in WKY rats. To determine whether reduced hippocampal BDNF in WKY rats was a contributing factor for their facilitated CCER, BDNF or saline infusions were given bilaterally into the dentate gyrus region 1 h prior to training. BDNF infusion did not alter the acquisition of SD rats, but significantly dampened the acquisition of CCER in the WKY rats, such that acquisition was similar to SD rats. Together, these results suggest that inherent differences in the BDNF system play a critical role in the facilitated associative learning exhibited by WKY rats, and potentially individuals with BI. Facilitated associative learning may represent a vulnerability factor in the development of anxiety disorders.

  5. Investigating the role of hippocampal BDNF in anxiety vulnerability using classical eyeblink conditioning

    Directory of Open Access Journals (Sweden)

    Kellie L Janke

    2015-07-01

    Full Text Available Dysregulation of brain-derived neurotrophic factor (BDNF, behavioral inhibition temperament (BI and small hippocampal volume have been linked to anxiety disorders. Individuals with BI show facilitated acquisition of the classically conditioned eyeblink response (CCER as compared to non-BI individuals, and a similar pattern is seen in an animal model of BI, the Wistar-Kyoto (WKY rat. The present study examined the role of hippocampal BDNF in the facilitated delay CCER of WKY rats. Consistent with earlier work, acquisition was facilitated in WKY rats compared to the SD rats. Facilitated acquisition was associated with increased BDNF, TrkB, and Arc mRNA in the dentate gyrus of SD rats, but learning-induced increases in BDNF and Arc mRNA were significantly smaller in WKY rats. To determine if reduced hippocampal BDNF in WKY rats was a contributing factor for their facilitated CCER, BDNF or saline infusions were given bilaterally into the dentate gyrus region one hour prior to training. BDNF infusion did not alter the acquisition of SD rats, but significantly dampened the acquisition of CCER in the WKY rats, such that acquisition was similar to SD rats. Together, these results suggest that inherent differences in the BDNF system play a critical role in the facilitated associative learning exhibited by WKY rats, and potentially individuals with BI. Facilitated associative learning may represent a vulnerability factor in the development of anxiety disorders.

  6. Impaired eye-blink conditioning in waggler, a mutant mouse with cerebellar BDNF deficiency.

    Science.gov (United States)

    Bao, S; Chen, L; Qiao, X; Knusel, B; Thompson, R F

    1998-01-01

    In addition to their trophic functions, neurotrophins are also implicated in synaptic modulation and learning and memory. Although gene knockout techniques have been used widely in studying the roles of neurotrophins at molecular and cellular levels, behavioral studies using neurotrophin knockouts are limited by the early-onset lethality and various sensory deficits associated with the gene knockout mice. In the present study, we found that in a spontaneous mutant mouse, waggler, the expression of brain-derived neurotrophic factor (BDNF) was selectively absent in the cerebellar granule cells. The cytoarchitecture of the waggler cerebellum appeared to be normal at the light microscope level. The mutant mice exhibited no sensory deficits to auditory stimuli or heat-induced pain. However, they were massively impaired in classic eye-blink conditioning. These results suggest that BDNF may have a role in normal cerebellar neuronal function, which, in turn, is essential for classic eye-blink conditioning.

  7. I Think, Therefore Eyeblink: The Importance of Contingency Awareness in Conditioning.

    Science.gov (United States)

    Weidemann, Gabrielle; Satkunarajah, Michelle; Lovibond, Peter F

    2016-04-01

    Can conditioning occur without conscious awareness of the contingency between the stimuli? We trained participants on two separate reaction time tasks that ensured attention to the experimental stimuli. The tasks were then interleaved to create a differential Pavlovian contingency between visual stimuli from one task and an airpuff stimulus from the other. Many participants were unaware of the contingency and failed to show differential eyeblink conditioning, despite attending to a salient stimulus that was contingently and contiguously related to the airpuff stimulus over many trials. Manipulation of awareness by verbal instruction dramatically increased awareness and differential eyeblink responding. These findings cast doubt on dual-system theories, which propose an automatic associative system independent of cognition, and provide strong evidence that cognitive processes associated with awareness play a causal role in learning.

  8. Enhanced conditioned eyeblink response acquisition and proactive interference in anxiety vulnerable individuals

    Directory of Open Access Journals (Sweden)

    Jacqueline L Holloway

    2012-11-01

    Full Text Available In classical conditioning, proactive interference may arise from experience with the conditioned stimulus (CS, the unconditional stimulus (US, or both, prior to their paired presentations. Interest in the application of proactive interference has extended to clinical populations as either a risk factor for disorders or as a secondary sign. Although the current literature is dense with comparisons of stimulus pre-exposure effects in animals, such comparisons are lacking in human subjects. As such, interpretation of proactive interference over studies as well as its generalization and utility in clinical research is limited. The present study was designed to assess eyeblink response acquisition after equal numbers of CS, US, and explicitly unpaired CS and US pre-exposures, as well as to evaluate how anxiety vulnerability might modulate proactive interference. In the current study, anxiety vulnerability was assessed using the State/Trait Anxiety Inventories as well as the adult and retrospective measures of behavioural inhibition (AMBI and RMBI, respectively. Participants were exposed to 1 of 4 possible pre-exposure contingencies: 30 CS, 30 US, 30 CS and 30 US explicitly unpaired pre-exposures, or context pre-exposure, immediately prior to standard delay training. Robust proactive interference was evident in all pre-exposure groups relative to context pre-exposure, independent of anxiety classification, with CR acquisition attenuated at similar rates. In addition, trait anxious individuals were found to have enhanced overall acquisition as well as greater proactive interference relative to non-vulnerable individuals. The findings suggest that anxiety vulnerable individuals learn implicit associations faster, an effect which persists after the introduction of new stimulus contingencies. This effect is not due to enhanced sensitivity to the US. Such differences would have implications for the development of anxiety psychopathology within a learning

  9. Purkinje cell activity in the cerebellar anterior lobe after rabbit eyeblink conditioning

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    Green, John T.; Steinmetz, Joseph E.

    2005-01-01

    The cerebellar anterior lobe may play a critical role in the execution and proper timing of learned responses. The current study was designed to monitor Purkinje cell activity in the rabbit cerebellar anterior lobe after eyeblink conditioning, and to assess whether Purkinje cells in recording locations may project to the interpositus nucleus. Rabbits were trained in an interstimulus interval discrimination procedure in which one tone signaled a 250-msec conditioned stimulus-unconditioned stimulus (CS-US) interval and a second tone signaled a 750-msec CS-US interval. All rabbits showed conditioned responses to each CS with mean onset and peak latencies that coincided with the CS-US interval. Many anterior lobe Purkinje cells showed significant learning-related activity after eyeblink conditioning to one or both of the CSs. More Purkinje cells responded with inhibition than with excitation to CS presentation. In addition, when the firing patterns of all conditioning-related Purkinje cells were pooled, it appeared that the population showed a pattern of excitation followed by inhibition during the CS-US interval. Using cholera toxin-conjugated horseradish peroxidase, Purkinje cells in recording areas were found to project to the interpositus nucleus. These data support previous studies that have suggested a role for the anterior cerebellar cortex in eyeblink conditioning as well as models of cerebellar-mediated CR timing that postulate that Purkinje cell activity inhibits conditioned response (CR) generation during the early portion of a trial by inhibiting the deep cerebellar nuclei and permits CR generation during the later portion of a trial through disinhibition of the cerebellar nuclei. PMID:15897252

  10. Short-term, high-dose administration of corticosterone by injection facilitates trace eyeblink conditioning in young male rats.

    Science.gov (United States)

    Wentworth-Eidsaune, Christine L; Hennessy, Michael B; Claflin, Dragana I

    2016-02-01

    Glucocorticoids released as part of the physiological response to stress are known to affect cognitive function, presumably via effects on the hippocampus. Trace classical eyeblink conditioning is an associative learning task which depends on the hippocampus and has been used to examine the development of learning processes in young mammals. Previously, we demonstrated deficits in trace eyeblink conditioning associated with postnatal administration of the glucocorticoid corticosterone by creating a sustained elevation with methods such as subcutaneous timed-release pellets and osmotic mini-pumps which were active over several days. In the present study, we examined the effects of an oscillating pattern of corticosterone elevation on subsequent trace eyeblink conditioning. Twice daily corticosterone injections (high, low, or vehicle) were administered over a 3-day period, starting at postnatal day 15. Then, on postnatal day 28, animals underwent trace classical eyeblink conditioning to examine the possible influence of earlier corticosterone elevations on the development of learning and memory. Eyeblink conditioning was affected by corticosterone treatments, but only for males, and only very early in acquisition; Males receiving the high dose of corticosterone exhibited facilitation of learning relative to controls. These data demonstrate that oscillating corticosterone elevations produce opposite effects on this associative learning task than do sustained elevations.

  11. Transfer of classical eyeblink conditioning with electrical stimulation of mPFC or tone as conditioned stimulus in guinea pigs.

    Science.gov (United States)

    Yao, Juan; Wu, Guang-Yan; Liu, Guo-Long; Liu, Shu-Lei; Yang, Yi; Wu, Bing; Li, Xuan; Feng, Hua; Sui, Jian-Feng

    2014-11-01

    Learning with a stimulus from one sensory modality can facilitate subsequent learning with a new stimulus from a different sensory modality. To date, the characteristics and mechanism of this phenomenon named transfer effect still remain ambiguous. Our previous work showed that electrical stimulation of medial prefrontal cortex (mPFC) as a conditioned stimulus (CS) could successfully establish classical eyeblink conditioning (EBC). The present study aimed to (1) observe whether transfer of EBC learning would occur when CSs shift between central (mPFC electrical stimulation as a CS, mPFC-CS) and peripheral (tone as a CS, tone CS); (2) compare the difference in transfer effect between the two paradigms, delay EBC (DEBC) and trace EBC (TEBC). A total of 8 groups of guinea pigs were tested in the study, including 4 experimental groups and 4 control groups. Firstly, the experimental groups accepted central (or peripheral) CS paired with corneal airpuff unconditioned stimulus (US); then, CS shifted to the peripheral (or central) and paired with US. The control groups accepted corresponding central (or peripheral) CS and pseudo-paired with US, and then shifted CS from central (or peripheral) to peripheral (or central) and paired with US. The results showed that the acquisition rates of EBC were higher in experimental groups than in control groups after CS switching from central to peripheral or vice versa, and the CR acquisition rate was remarkably higher in DEBC than in TEBC in both transfer ways. The results indicate that EBC transfer can occur between learning established with mPFC-CS and tone CS. Memory of CS-US association for delay paradigm was less disturbed by the sudden switch of CS than for trace paradigm. This study provides new insight into neural mechanisms underlying conditioned reflex as well as the role of mPFC.

  12. Harnessing the power of theta: natural manipulations of cognitive performance during hippocampal theta-contingent eyeblink conditioning

    Science.gov (United States)

    Hoffmann, Loren C.; Cicchese, Joseph J.; Berry, Stephen D.

    2015-01-01

    Neurobiological oscillations are regarded as essential to normal information processing, including coordination and timing of cells and assemblies within structures as well as in long feedback loops of distributed neural systems. The hippocampal theta rhythm is a 3–12 Hz oscillatory potential observed during cognitive processes ranging from spatial navigation to associative learning. The lower range, 3–7 Hz, can occur during immobility and depends upon the integrity of cholinergic forebrain systems. Several studies have shown that the amount of pre-training theta in the rabbit strongly predicts the acquisition rate of classical eyeblink conditioning and that impairment of this system substantially slows the rate of learning. Our lab has used a brain-computer interface (BCI) that delivers eyeblink conditioning trials contingent upon the explicit presence or absence of hippocampal theta. A behavioral benefit of theta-contingent training has been demonstrated in both delay and trace forms of the paradigm with a two- to four-fold increase in learning speed. This behavioral effect is accompanied by enhanced amplitude and synchrony of hippocampal local field potential (LFP)s, multi-unit excitation, and single-unit response patterns that depend on theta state. Additionally, training in the presence of hippocampal theta has led to increases in the salience of tone-induced unit firing patterns in the medial prefrontal cortex, followed by persistent multi-unit activity during the trace interval. In cerebellum, rhythmicity and precise synchrony of stimulus time-locked LFPs with those of hippocampus occur preferentially under the theta condition. Here we review these findings, integrate them into current models of hippocampal-dependent learning and suggest how improvement in our understanding of neurobiological oscillations is critical for theories of medial temporal lobe processes underlying intact and pathological learning. PMID:25918501

  13. Autism and classical eyeblink conditioning: Performance changes of the conditioned response related to autism spectrum disorder diagnosis

    Directory of Open Access Journals (Sweden)

    John P Welsh

    2016-08-01

    Full Text Available Changes in the timing performance of conditioned responses (CRs acquired during trace and delay eyeblink conditioning (EBC are presented for diagnostic subgroups of children having autism spectrum disorder (ASD aged 6-15 years. Children diagnosed with autistic disorder (AD were analyzed separately from children diagnosed with either Asperger’s syndrome or Pervasive-developmental disorder not-otherwise-specified (Asp/PDD and compared to an age- and IQ-matched group of children that were typically developing (TD. Within-subject and between-groups contrasts in CR performance on sequential exposure to trace and delay EBC were analyzed to determine whether any differences would expose underlying functional heterogeneities of the cerebral and cerebellar systems in ASD subgroups. The EBC parameters measured were percentage CRs, CR onset latency, and CR peak latency. Neither AD nor Asp/PDD groups were impaired in CR acquisition during trace or delay EBC. AD and Asp/PDD both altered CR timing, but not always in the same way. Although the AD group showed normal CR timing during trace EBC, the Asp/PDD group showed a significant 27 and 28 ms increase in CR onset and peak latency, respectively, during trace EBC. In contrast, the direction of the timing change was opposite during delay EBC, during which the Asp/PDD group showed a significant 29 ms decrease in CR onset latency and the AD group showed a larger 77 ms decrease in CR onset latency. Only the AD group showed a decrease in CR peak latency during delay EBC, demonstrating another difference between AD and Asp/PDD. The difference in CR onset latency during delay EBC for both AD and Asp/PDD was due to an abnormal prevalence of early onset CRs that were intermixed with CRs having normal timing, as observed both in CR onset histograms and mean CR waveforms. In conclusion, significant heterogeneity in EBC performance was apparent within diagnostic groups, and this may indicate that EBC performance can

  14. Hippocampal ripple-contingent training accelerates trace eyeblink conditioning and retards extinction in rabbits.

    Science.gov (United States)

    Nokia, Miriam S; Penttonen, Markku; Wikgren, Jan

    2010-08-25

    There are at least two distinct oscillatory states of the hippocampus that are related to distinct behavioral patterns. Theta (4-12 Hz) oscillation has been suggested to indicate selective attention during which the animal concentrates on some features of the environment while suppressing reactivity to others. In contrast, sharp-wave ripples ( approximately 200 Hz) can be seen in a state in which the hippocampus is at its most responsive to any kind of afferent stimulation. In addition, external stimulation tends to evoke and reset theta oscillation, the phase of which has been shown to modulate synaptic plasticity in the hippocampus. Theoretically, training on a hippocampus-dependent learning task contingent upon ripples could enhance learning rate due to elevated responsiveness and enhanced phase locking of the theta oscillation. We used a brain-computer interface to detect hippocampal ripples in rabbits to deliver trace eyeblink conditioning and extinction trials selectively contingent upon them. A yoked control group was trained regardless of their ongoing neural state. Ripple-contingent training expedited acquisition of the conditioned response early in training and evoked stronger theta-band phase locking to the conditioned stimulus. Surprisingly, ripple-contingent training also resulted in slower extinction in well trained animals. We suggest that the ongoing oscillatory activity in the hippocampus determines the extent to which a stimulus can induce a phase reset of the theta oscillation, which in turn is the determining factor of learning rate in trace eyeblink conditioning.

  15. Both Trace and Delay Conditioning of Evaluative Responses Depend on Contingency Awareness

    Science.gov (United States)

    Kattner, Florian; Ellermeier, Wolfgang; Tavakoli, Paniz

    2012-01-01

    Whereas previous evaluative conditioning (EC) studies produced inconsistent results concerning the role of contingency knowledge, there are classical eye-blink conditioning studies suggesting that declarative processes are involved in trace conditioning but not in delay conditioning. In two EC experiments pairing neutral sounds (conditioned…

  16. Stimulation of the Lateral Geniculate, Superior Colliculus, or Visual Cortex is Sufficient for Eyeblink Conditioning in Rats

    Science.gov (United States)

    Halverson, Hunter E.; Hubbard, Erin M.; Freeman, John H.

    2009-01-01

    The role of the cerebellum in eyeblink conditioning is well established. Less work has been done to identify the necessary conditioned stimulus (CS) pathways that project sensory information to the cerebellum. A possible visual CS pathway has been hypothesized that consists of parallel inputs to the pontine nuclei from the lateral geniculate…

  17. Dimethoate accelerates the extinction of eyeblink conditioning in mice.

    Science.gov (United States)

    Valenzuela-Harrington, Mauricio; Castillo, Irene; Díaz, Corín; Alés, Inés; Rodríguez-Moreno, Antonio

    2012-01-01

    In agriculture, organophosphates are frequently used as insecticides and pesticides. These compounds decrease acetylcholine esterase (AChE) activity, thereby provoking an accumulation of the neurotransmitter acetylcholine at synapses and resulting in the over-stimulation of acetylcholine receptors. Using trace paradigms, we investigated the effects of dimethoate, a widely used organophosphate insecticide, on the classical conditioning of eyelid responses, a hippocampal-dependent mouse model of associative learning. Mice were conditioned with a trace shock-SHOCK paradigm having first implanted stimulating electrodes in the supraorbitary nerve and recording electrodes in the ipsilateral orbicularis oculi muscle. When these mice were injected with dimethoate (5, 20, 50mg/kg/day) they were capable of acquiring associative learning, and the latency and amplitude of their unconditioned eyelid responses were unaffected by the administration of the pesticide. However, dimethoate administration led to the rapid extinction of conditioned responses, suggesting that this organophosphate accelerates the extinction of this form of associative learning. Analysis of the motor function of these mice using the rotarod performance test revealed that motor function and performance clearly deteriorated following dimethoate administration, with no improvements over the following 4 days. Together these findings indicate that dimethoate accelerates the extinction of acquired conditioned responses, affecting associative learning and memory, and it impairs motor function and performance in mice.

  18. The role of US recency in the Perruchet effect in eyeblink conditioning.

    Science.gov (United States)

    Weidemann, Gabrielle; Lovibond, Peter F

    2016-09-01

    In the Perruchet effect, there is a concurrent dissociation between participants' conditioned responses (CRs) and their expectancy of the unconditioned stimulus (US) across runs of repeated trials. The effect has been taken as evidence for multiple learning processes, but this conclusion follows only if the CR trend is the result of learning. Two experiments examined the role of US recency in generating the observed CR trend. A standard Perruchet condition was compared with a control condition in which US recency was controlled by presenting the US on every trial. The associative contribution was maintained by varying the temporal relationship between the CS and the US. In both experiments the pattern of CRs seen in the Perruchet condition was absent in the control condition, suggesting that the eyeblink trend in the Perruchet effect may be due to a non-associative performance factor such as priming or sensitization arising from recent US presentations.

  19. Prolonging the postcomplex spike pause speeds eyeblink conditioning.

    Science.gov (United States)

    Maiz, Jaione; Karakossian, Movses H; Pakaprot, Narawut; Robleto, Karla; Thompson, Richard F; Otis, Thomas S

    2012-10-09

    Climbing fiber input to the cerebellum is believed to serve as a teaching signal during associative, cerebellum-dependent forms of motor learning. However, it is not understood how this neural pathway coordinates changes in cerebellar circuitry during learning. Here, we use pharmacological manipulations to prolong the postcomplex spike pause, a component of the climbing fiber signal in Purkinje neurons, and show that these manipulations enhance the rate of learning in classical eyelid conditioning. Our findings elucidate an unappreciated aspect of the climbing fiber teaching signal, and are consistent with a model in which convergent postcomplex spike pauses drive learning-related plasticity in the deep cerebellar nucleus. They also suggest a physiological mechanism that could modulate motor learning rates.

  20. Using eyeblink classical conditioning as a test of the functional consequences of exposure of the developing cerebellum to alcohol.

    Science.gov (United States)

    Green, John T

    2003-01-01

    Exposure of the developing brain to alcohol produces profound Purkinje cell loss in the cerebellum, and deficits in tests of motor coordination. However, the precise relationship between these two sets of findings has been difficult to determine. Eyeblink classical conditioning is known to engage a discrete brainstem-cerebellar circuit, making it an ideal test of cerebellar functional integrity after developmental alcohol exposure. In eyeblink conditioning, one of the deep cerebellar nuclei, the interpositus nucleus, as well as specific Purkinje cell populations, are sites of convergence for CS and US information. A series of studies have shown that eyeblink conditioning is impaired in both weanling and adult rats given binge-like exposure to alcohol as neonates, and that these deficits can be traced, at least in part, to impaired activation of cerebellar interpositus nucleus neurons and to an overall reduction in the deep cerebellar nuclear cell population. Because particular cerebellar cell populations are utilized in well-defined ways during eyeblink conditioning, conclusions regarding specific changes in the mediation of behavior by these cell populations are greatly strengthened. Further studies will be directed towards the impact of early exposure to alcohol on the functionality of specific Purkinje cell populations, as well as towards brainstem areas that process the tone CS and the somatosensory US.

  1. PKMzeta inhibition reverses learning-induced increases in hippocampal synaptic strength and memory during trace eyeblink conditioning.

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    Noelia Madroñal

    Full Text Available A leading candidate in the process of memory formation is hippocampal long-term potentiation (LTP, a persistent enhancement in synaptic strength evoked by the repetitive activation of excitatory synapses, either by experimental high-frequency stimulation (HFS or, as recently shown, during actual learning. But are the molecular mechanisms for maintaining synaptic potentiation induced by HFS and by experience the same? Protein kinase Mzeta (PKMzeta, an autonomously active atypical protein kinase C isoform, plays a key role in the maintenance of LTP induced by tetanic stimulation and the storage of long-term memory. To test whether the persistent action of PKMzeta is necessary for the maintenance of synaptic potentiation induced after learning, the effects of ZIP (zeta inhibitory peptide, a PKMzeta inhibitor, on eyeblink-conditioned mice were studied. PKMzeta inhibition in the hippocampus disrupted both the correct retrieval of conditioned responses (CRs and the experience-dependent persistent increase in synaptic strength observed at CA3-CA1 synapses. In addition, the effects of ZIP on the same associative test were examined when tetanic LTP was induced at the hippocampal CA3-CA1 synapse before conditioning. In this case, PKMzeta inhibition both reversed tetanic LTP and prevented the expected LTP-mediated deleterious effects on eyeblink conditioning. Thus, PKMzeta inhibition in the CA1 area is able to reverse both the expression of trace eyeblink conditioned memories and the underlying changes in CA3-CA1 synaptic strength, as well as the anterograde effects of LTP on associative learning.

  2. Eyeblink Classical Conditioning and Post Traumatic Stress Disorder – A Model Systems Approach

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    Bernard G Schreurs

    2015-04-01

    Full Text Available Not everyone exposed to trauma suffers flashbacks, bad dreams, numbing, fear, anxiety, sleeplessness, hyper-vigilance, hyperarousal, or an inability to cope, but those who do may suffer from post traumatic stress disorder (PTSD. PTSD is a major physical and mental health problem for military personnel and civilians exposed to trauma. There is still debate about the incidence and prevalence of PTSD especially among the military, but for those who are diagnosed, behavioral therapy and drug treatment strategies have proven to be less than effective. A number of these treatment strategies are based on rodent fear conditioning research and are capable of treating only some of the symptoms because the extinction of fear does not deal with the various forms of hyper-vigilance and hyperarousal experienced by people with PTSD. To help address this problem, we have developed a preclinical eyeblink classical conditioning model of PTSD in which conditioning and hyperarousal can both be extinguished. We review this model and discuss findings showing that unpaired stimulus presentations can be effective in reducing levels of conditioning and hyperarousal even when unconditioned stimulus intensity is reduced to the point where it is barely capable of eliciting a response. These procedures have direct implications for the treatment of PTSD and could be implemented in a virtual reality environment.

  3. Eyeblink classical conditioning and post-traumatic stress disorder - a model systems approach.

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    Schreurs, Bernard G; Burhans, Lauren B

    2015-01-01

    Not everyone exposed to trauma suffers flashbacks, bad dreams, numbing, fear, anxiety, sleeplessness, hyper-vigilance, hyperarousal, or an inability to cope, but those who do may suffer from post-traumatic stress disorder (PTSD). PTSD is a major physical and mental health problem for military personnel and civilians exposed to trauma. There is still debate about the incidence and prevalence of PTSD especially among the military, but for those who are diagnosed, behavioral therapy and drug treatment strategies have proven to be less than effective. A number of these treatment strategies are based on rodent fear conditioning research and are capable of treating only some of the symptoms because the extinction of fear does not deal with the various forms of hyper-vigilance and hyperarousal experienced by people with PTSD. To help address this problem, we have developed a preclinical eyeblink classical conditioning model of PTSD in which conditioning and hyperarousal can both be extinguished. We review this model and discuss findings showing that unpaired stimulus presentations can be effective in reducing levels of conditioning and hyperarousal even when unconditioned stimulus intensity is reduced to the point where it is barely capable of eliciting a response. These procedures have direct implications for the treatment of PTSD and could be implemented in a virtual reality environment.

  4. Eyeblink conditioning in unmedicated schizophrenia patients: a positron emission tomography study.

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    Parker, Krystal L; Andreasen, Nancy C; Liu, Dawei; Freeman, John H; O'Leary, Daniel S

    2013-12-30

    Previous studies suggest that patients with schizophrenia exhibit dysfunctions in a widely distributed circuit-the cortico-cerebellar-thalamic-cortical circuit, or CCTCC-and that this may explain the multiple cognitive deficits observed in the disorder. This study uses positron emission tomography (PET) with O(15) H₂O to measure regional cerebral blood flow (rCBF) in response to a classic test of cerebellar function, the associative learning that occurs during eyeblink conditioning, in a sample of 20 unmedicated schizophrenia patients and 20 closely matched healthy controls. The PET paradigm examined three phases of acquisition and extinction (early, middle and late). The patients displayed impaired behavioral performance during both acquisition and extinction. The imaging data indicate that, compared to the control subjects, the patients displayed decreases in rCBF in all three components of the CCTCC during both acquisition and extinction. Specifically, patients had less rCBF in the middle and medial frontal lobes, anterior cerebellar lobules I/V and VI, as well as the thalamus during acquisition and although similar areas were found in the frontal lobe, ipsilateral cerebellar lobule IX showed consistently less activity in patients during extinction. Thus this study provides additional support for the hypothesis that patients with schizophrenia have a cognitive dysmetria--an inability to smoothly coordinate many different types of mental activity--that affects even a very basic cognitive task that taps into associative learning.

  5. New insights into the nature of cerebellar-dependent eyeblink conditioning deficits in schizophrenia: A hierarchical linear modeling approach

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    Amanda R Bolbecker

    2016-01-01

    Full Text Available Evidence of cerebellar dysfunction in schizophrenia has mounted over the past several decades, emerging from neuroimaging, neuropathological, and behavioral studies. Consistent with these findings, cerebellar-dependent delay eyeblink conditioning (dEBC deficits have been identified in schizophrenia. While repeated measures analysis of variance (ANOVA is traditionally used to analyze dEBC data, hierarchical linear modeling (HLM more reliably describes change over time by accounting for the dependence in repeated measures data. This analysis approach is well suited to dEBC data analysis because it has less restrictive assumptions and allows unequal variances. The current study examined dEBC measured with electromyography in a single-cue tone paradigm in an age-matched sample of schizophrenia participants and healthy controls (N=56 per group using HLM. Subjects participated in 90 trials (10 blocks of dEBC, during which a 400 ms tone co-terminated with a 50 ms air puff delivered to the left eye. Each block also contained 1 tone-alone trial. The resulting block averages of dEBC data were fitted to a 3-parameter logistic model in HLM, revealing significant differences between schizophrenia and control groups on asymptote and inflection point, but not slope. These findings suggest that while the learning rate is not significantly different compared to controls, associative learning begins to level off later and a lower ultimate level of associative learning is achieved in schizophrenia. Given the large sample size in the present study, HLM may provide a more nuanced and definitive analysis of differences between schizophrenia and controls on dEBC.

  6. New Insights into the Nature of Cerebellar-Dependent Eyeblink Conditioning Deficits in Schizophrenia: A Hierarchical Linear Modeling Approach.

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    Bolbecker, Amanda R; Petersen, Isaac T; Kent, Jerillyn S; Howell, Josselyn M; O'Donnell, Brian F; Hetrick, William P

    2016-01-01

    Evidence of cerebellar dysfunction in schizophrenia has mounted over the past several decades, emerging from neuroimaging, neuropathological, and behavioral studies. Consistent with these findings, cerebellar-dependent delay eyeblink conditioning (dEBC) deficits have been identified in schizophrenia. While repeated-measures analysis of variance is traditionally used to analyze dEBC data, hierarchical linear modeling (HLM) more reliably describes change over time by accounting for the dependence in repeated-measures data. This analysis approach is well suited to dEBC data analysis because it has less restrictive assumptions and allows unequal variances. The current study examined dEBC measured with electromyography in a single-cue tone paradigm in an age-matched sample of schizophrenia participants and healthy controls (N = 56 per group) using HLM. Subjects participated in 90 trials (10 blocks) of dEBC, during which a 400 ms tone co-terminated with a 50 ms air puff delivered to the left eye. Each block also contained 1 tone-alone trial. The resulting block averages of dEBC data were fitted to a three-parameter logistic model in HLM, revealing significant differences between schizophrenia and control groups on asymptote and inflection point, but not slope. These findings suggest that while the learning rate is not significantly different compared to controls, associative learning begins to level off later and a lower ultimate level of associative learning is achieved in schizophrenia. Given the large sample size in the present study, HLM may provide a more nuanced and definitive analysis of differences between schizophrenia and controls on dEBC.

  7. Enhanced Eyeblink Conditioning in Behaviorally Inhibited Individuals is Disrupted by Proactive Interference Following US Alone Pre-exposures.

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    Allen, Michael Todd; Miller, Daniel P

    2016-01-01

    Anxiety vulnerable individuals exhibit enhanced acquisition of conditioned eyeblinks as well as enhanced proactive interference from conditioned stimulus (CS) or unconditioned stimulus (US) alone pre-exposures (Holloway et al., 2012). US alone pre-exposures disrupt subsequent conditioned response (CR) acquisition to CS-US paired trials as compared to context pre-exposure controls. While Holloway et al. (2012) reported enhanced acquisition in high trait anxiety individuals in the context condition, anxiety vulnerability effects were not reported for the US alone pre-exposure group. It appears from the published data that there were no differences between high and low anxiety individuals in the US alone condition. In the work reported here, we sought to extend the findings of enhanced proactive interference with US alone pre-exposures to determine if the enhanced conditioning was disrupted by proactive interference procedures. We also were interested in the spontaneous eyeblinks during the pre-exposure phase of training. We categorized individuals as anxiety vulnerability or non-vulnerable individuals based scores on the Adult Measure of Behavioral Inhibition (AMBI). Sixty-six participants received 60 trials consisting of 30 US alone or context alone pre-exposures followed by 30 CS-US trials. US alone pre-exposures not only disrupted CR acquisition overall, but behaviorally inhibited (BI) individuals exhibited enhanced proactive interference as compared to non-inhibited (NI) individuals. In addition, US alone pre-exposures disrupted the enhanced acquisition observed in BI individuals as compared to NI individuals following context alone pre-exposures. Differences were also found in rates of spontaneous eyeblinks between BI and NI individuals during context pre-exposure. Our findings will be discussed in the light of the neural substrates of eyeblink conditioning as well as possible factors such as hypervigilance in the amygdala and hippocampal systems, and possible

  8. Predictive nature of prefrontal theta oscillation on the performance of trace conditioned eyeblink responses in guinea pigs.

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    Chen, Hao; Wang, Yi-jie; Yang, Li; Hu, Chen; Ke, Xian-feng; Fan, Zheng-li; Sui, Jian-feng; Hu, Bo

    2014-05-15

    Stimulus-evoked theta oscillations are observed in the medial prefrontal cortex (mPFC) when executing a variety of learning tasks. Here, we aimed to further determine whether spontaneous theta-band (5.0-10.0 Hz) oscillations in the mPFC predicted the subsequent behavioral performance in trace eyeblink conditioning (TEBC), in which the conditioned stimulus (CS) was separated from the unconditioned stimulus (US) by 500 ms trace interval. By recording local field potentials (LFP) signals in the guinea pigs performing the TEBC task, we found that, a higher mPFC relative theta ratio [theta/(delta+beta)] during the baseline (850-ms period prior to the onset of the CS) was predictive of higher magnitude and more adaptive timing rather than faster acquisition of trace conditioned eyeblink responses (CR). However, the prediction of baseline mPFC theta activity was time-limited to the well-learning stage. Additionally, the relative power of mPFC theta activity did not correlate with the CR performance if the trace interval between the CS and the US was shortened to 100 ms. These results suggest that the brain state in which the baseline mPFC theta activity is present or absent is detrimental for the subsequent performance of trace CRs especially when the asymptotic learning state is achieved.

  9. Avoidance Prone Individuals Self Reporting Behavioral Inhibition Exhibit Facilitated Acquisition and Altered Extinction of Conditioned Eyeblinks With Partial Reinforcement Schedules

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    Michael Todd Allen

    2014-10-01

    Full Text Available Avoidance in the face of novel situations or uncertainty is a prime feature of behavioral inhibition which has been put forth as a risk factor for the development of anxiety disorders. Recent work has found that behaviorally inhibited individuals acquire conditioned eyeblinks faster than non-inhibited individuals in omission and yoked paradigms in which the predictive relationship between the conditioned stimulus (CS and unconditional stimulus (US is less than optimal as compared to standard training with CS-US paired trials (Holloway et al., 2014. In the current study, we tested explicitly partial schedules in which half the trials were CS alone or US alone trials in addition to the standard CS-US paired trials. One hundred and forty nine college-aged undergraduates participated in the study. All participants completed the Adult Measure of Behavioral Inhibition (i.e., AMBI which was used to group participants as behaviorally inhibited and non-inhibited. Eyeblink conditioning consisted of 3 US alone trials, 60 acquisition trials, and 20 CS-alone extinction trials presented in one session. Conditioning stimuli were a 500 ms tone conditioned stimulus (CS and a 50-ms air puff unconditional stimulus (US. Behaviorally inhibited individuals receiving 50% partial reinforcement with CS alone or US alone trials produced facilitated acquisition as compared to non-inhibited individuals. A partial reinforcement extinction effect was evident with CS alone trials in behaviorally inhibited but not non-inhibited individuals. These current findings indicate that avoidance prone individuals self-reporting behavioral inhibition over-learn an association and are slow to extinguish conditioned responses when there is some level of uncertainty between paired trials and CS or US alone presentations.

  10. Avoidance prone individuals self reporting behavioral inhibition exhibit facilitated acquisition and altered extinction of conditioned eyeblinks with partial reinforcement schedules.

    Science.gov (United States)

    Allen, Michael Todd; Myers, Catherine E; Servatius, Richard J

    2014-01-01

    Avoidance in the face of novel situations or uncertainty is a prime feature of behavioral inhibition which has been put forth as a risk factor for the development of anxiety disorders. Recent work has found that behaviorally inhibited (BI) individuals acquire conditioned eyeblinks faster than non-inhibited (NI) individuals in omission and yoked paradigms in which the predictive relationship between the conditioned stimulus (CS) and unconditional stimulus (US) is less than optimal as compared to standard training with CS-US paired trials (Holloway et al., 2014). In the current study, we tested explicitly partial schedules in which half the trials were CS alone or US alone trials in addition to the standard CS-US paired trials. One hundred and forty nine college-aged undergraduates participated in the study. All participants completed the Adult Measure of Behavioral Inhibition (i.e., AMBI) which was used to group participants as BI and NI. Eyeblink conditioning consisted of three US alone trials, 60 acquisition trials, and 20 CS-alone extinction trials presented in one session. Conditioning stimuli were a 500 ms tone CS and a 50-ms air puff US. Behaviorally inhibited individuals receiving 50% partial reinforcement with CS alone or US alone trials produced facilitated acquisition as compared to NI individuals. A partial reinforcement extinction effect (PREE) was evident with CS alone trials in BI but not NI individuals. These current findings indicate that avoidance prone individuals self-reporting behavioral inhibition over-learn an association and are slow to extinguish conditioned responses (CRs) when there is some level of uncertainty between paired trials and CS or US alone presentations.

  11. Eyeblink classical conditioning and interpositus nucleus activity are disrupted in adult rats exposed to ethanol as neonates.

    Science.gov (United States)

    Green, John T; Johnson, Timothy B; Goodlett, Charles R; Steinmetz, Joseph E

    2002-01-01

    Neonatal exposure to ethanol in rats, during the period of brain development comparable to that of the human third trimester, produces significant, dose-dependent cell loss in the cerebellum and deficits in coordinated motor performance. These rats are also impaired in eyeblink conditioning as weanlings and as adults. The current study examined single-unit neural activity in the interpositus nucleus of the cerebellum in adults following neonatal binge ethanol exposure. Group Ethanol received alcohol doses of 5.25 g/kg/day on postnatal days 4-9. Group Sham Intubated underwent acute intragastric intubation on postnatal days 4-9 but did not receive any infusions. Group Unintubated Control (from separate litters) did not receive any intubations. When rats were 3-7 mo old, pairs of extracellular microelectrodes were implanted in the region of the interpositus nucleus. Beginning 1 wk later, the rats were given either 100 paired or 190 unpaired trials per day for 10 d followed by 4 d of 100 conditioned stimulus (CS)-alone trials per day. As in our previous study, conditioned response acquisition in Group Ethanol rats was impaired. In addition, by session 5 of paired acquisition, Group Sham Intubated and Group Unintubated Control showed significant increases in interpositus nucleus activity, relative to baseline, in the CS-unconditioned stimulus interval. In contrast, Group Ethanol failed to show significant changes in interpositus nucleus activity until later in training. These results indicate that the disruption in eyeblink conditioning after early exposure to ethanol is reflected in alterations in interpositus nucleus activity.

  12. Eyeblink Classical Conditioning and Interpositus Nucleus Activity Are Disrupted in Adult Rats Exposed to Ethanol as Neonates

    Science.gov (United States)

    Green, John T.; Johnson, Timothy B.; Goodlett, Charles R.; Steinmetz, Joseph E.

    2002-01-01

    Neonatal exposure to ethanol in rats, during the period of brain development comparable to that of the human third trimester, produces significant, dose-dependent cell loss in the cerebellum and deficits in coordinated motor performance. These rats are also impaired in eyeblink conditioning as weanlings and as adults. The current study examined single-unit neural activity in the interpositus nucleus of the cerebellum in adults following neonatal binge ethanol exposure. Group Ethanol received alcohol doses of 5.25 g/kg/day on postnatal days 4–9. Group Sham Intubated underwent acute intragastric intubation on postnatal days 4–9 but did not receive any infusions. Group Unintubated Control (from separate litters) did not receive any intubations. When rats were 3–7 mo old, pairs of extracellular microelectrodes were implanted in the region of the interpositus nucleus. Beginning 1 wk later, the rats were given either 100 paired or 190 unpaired trials per day for 10 d followed by 4 d of 100 conditioned stimulus (CS)-alone trials per day. As in our previous study, conditioned response acquisition in Group Ethanol rats was impaired. In addition, by session 5 of paired acquisition, Group Sham Intubated and Group Unintubated Control showed significant increases in interpositus nucleus activity, relative to baseline, in the CS–unconditioned stimulus interval. In contrast, Group Ethanol failed to show significant changes in interpositus nucleus activity until later in training. These results indicate that the disruption in eyeblink conditioning after early exposure to ethanol is reflected in alterations in interpositus nucleus activity. PMID:12359839

  13. Effect of varying the intensity and train frequency of forelimb and cerebellar mossy fiber conditioned stimuli on the latency of conditioned eye-blink responses in decerebrate ferrets.

    Science.gov (United States)

    Svensson, P; Ivarsson, M; Hesslow, G

    1997-01-01

    To study the role of the mossy fiber afferents to the cerebellum in classical eye-blink conditioning, in particular the timing of the conditioned responses, we compared the effects of varying a peripheral conditioned stimulus with the effects of corresponding variations of direct stimulation of the mossy fibers. In one set of experiments, decerebrate ferrets were trained in a Pavlovian eye-blink conditioning paradigm with electrical forelimb train stimulation as conditioned stimulus and electrical periorbital stimulation as the unconditioned stimulus. When stable conditioning had been achieved, the effect of increasing the intensity or frequency of the forelimb stimulation was tested. By increasing the intensity from 1 to 2 mA, or the train frequency from 50 to 100 Hz, an immediate decrease was induced in both the onset latency and the latency to peak of the conditioned response. If the conditioned stimulus intensity/frequency was maintained at the higher level, the response latencies gradually returned to preshift values. In a second set of experiments, the forelimb stimulation was replaced by direct train stimulation of the middle cerebellar peduncle as conditioned stimulus. Varying the frequency of the stimulus train between 50 and 100 Hz had effects that were almost identical to those obtained when using a forelimb conditioned stimulus. The functional meaning of the latency effect is discussed. It is also suggested that the results support the view that the conditioned stimulus is transmitted through the mossy fibers and that the mechanism for timing the conditioned response is situated in the cerebellum.

  14. Involvement of the ipsilateral and contralateral cerebellum in the acquisition of unilateral classical eyeblink conditioning in guinea pigs

    Institute of Scientific and Technical Information of China (English)

    Bo HU; Xi LIN; Lushuai HUANG; Li YANG; Hua FENG; Jianfeng SUI

    2009-01-01

    Aim:The aim of this study was to evaluate the relative contributions of the ipsilateral and contralateral cerebellum to the acquisition of unilateral classical eyeblink conditioning (EBCC).Methods: The unilateral EBCC was achieved using a binaural tone conditioned stimulus (CS) paired with a left airpuff unconditioned stimulus (US).A high-resolution potentiometer was used to monitor eyeblink responses.Guinea pigs received one CS-US session followed by three CS-US sessions (sessions 2 to 4),during which microinjections of muscimol,a GABAA receptor agonist,were performed to reversibly inactivate the cerebellum unilaterally prior to training.To test whether any learning had occurred during these inactivation sessions,training was continued for six more CS-US sessions (sessions 5 to 10) without any inactivation.Results: Animals with inactivation of the left cerebellum had no signs of left conditioned response (CR) during sessions 2 to 4,and their CR acquisition during sessions 5 to 10 was not distinguishable from that of control animals during sessions 2 to 7.In contrast,animals with inactivation of the right cerebellum acquired left CRs during sessions 2 to 4,although their CR acquisition was significantly retarded during session 2.In addition,microinjections of muscimol into the right cerebellum did not affect left neuro-behavioral activity.Finally,microinjections of muscimol into either the left or the right cerebellum did not affect the performance of tone-airpuff evoked unconditioned response (UR).Conclusion: In contrast to the essential role of the ipsilateral cerebellum,the contralateral cerebellum is potentially involved in the acquisition of unilateral EBCC during the early stage of training.

  15. Pronounced reduction of acquisition of conditioned eyeblink responses in young adults with focal cerebellar lesions impedes conclusions on the role of the cerebellum in extinction and savings.

    Science.gov (United States)

    Ernst, T M; Beyer, L; Mueller, O M; Göricke, S; Ladd, M E; Gerwig, M; Timmann, D

    2016-05-01

    Human cerebellar lesion studies provide good evidence that the cerebellum contributes to the acquisition of classically conditioned eyeblink responses (CRs). As yet, only one study used more advanced methods of lesion-symptom (or lesion-behavior) mapping to investigate which cerebellar areas are involved in CR acquisition in humans. Likewise, comparatively few studies investigated the contribution of the human cerebellum to CR extinction and savings. In this present study, young adults with focal cerebellar disease were tested. A subset of participants was expected to acquire enough conditioned responses to allow the investigation of extinction and saving effects. 19 participants with chronic surgical lesions of the cerebellum and 19 matched control subjects were tested. In all cerebellar subjects benign tumors of the cerebellum had been surgically removed. Eyeblink conditioning was performed using a standard short delay protocol. An initial unpaired control phase was followed by an acquisition phase, an extinction phase and a subsequent reacquisition phase. Structural 3T magnetic resonance images of the brain were acquired on the day of testing. Cerebellar lesions were normalized using methods optimized for the cerebellum. Subtraction analysis and Liebermeister tests were used to perform lesion-symptom mapping. As expected, CR acquisition was significantly reduced in cerebellar subjects compared to controls. Reduced CR acquisition was significantly more likely in participants with lesions of lobule VI and Crus I extending into Crus II (pacquisition, extinction and savings within the normal range; and a larger group (n=14) which did not show acquisition. In the latter, no conclusions on extinction or savings could be drawn. Previous findings were confirmed that circumscribed areas in lobule VI and Crus I are of major importance in CR acquisition. In addition, the present data suggest that if the critical regions of the cerebellar cortex are lesioned, the ability to

  16. Cleavage of proBDNF to BDNF by a tolloid-like metalloproteinase is required for acquisition of in vitro eyeblink classical conditioning.

    Science.gov (United States)

    Keifer, Joyce; Sabirzhanov, Boris E; Zheng, Zhaoqing; Li, Wei; Clark, Timothy G

    2009-11-25

    The tolloid/bone morphogenetic protein-1 family of metalloproteinases have an important role in the regulation of embryonic pattern formation and tissue morphogenesis. Studies suggest that they participate in mechanisms of synaptic plasticity in adults, but very little is known about their function. Recently, we isolated a reptilian ortholog of the tolloid gene family designated turtle tolloid-like gene (tTll). Here, we examined the role of tTLL in an in vitro model of eyeblink classical conditioning using an isolated brainstem preparation to assess its role in synaptic plasticity during conditioning. Analysis by real-time reverse transcription-PCR shows that an extracellularly secreted form of tTLL, tTLLs, is transiently expressed in the early stages of conditioning during conditioned response acquisition, whereas a cytosolic form, tTLLc, is not. Short interfering RNA (siRNA)-directed gene knockdown and rescue of tTLL expression demonstrate that it is required for conditioning. Significantly, we show that tTLLs cleaves the precursor proBDNF into mature BDNF in cleavage assay studies, and application of recombinant tTLLs protein alone to preparations results in induction of mature BDNF expression. The mature form of BDNF is minimally expressed in preparations treated with anti-tTLL siRNA, and the synaptic incorporation of both GluR1- and GluR4-containing AMPA receptors is significantly reduced, resulting in suppression of conditioning. This is the first study to demonstrate that expression of an extracellularly secreted tolloid-like metalloproteinase is regulated in the early stages of classical conditioning and functions in the conversion of proBDNF to mature BDNF. The mature form of BDNF is required for synaptic delivery of AMPA receptors and acquisition of conditioned responses.

  17. Why trace and delay conditioning are sometimes (but not always) hippocampal dependent: a computational model.

    Science.gov (United States)

    Moustafa, Ahmed A; Wufong, Ella; Servatius, Richard J; Pang, Kevin C H; Gluck, Mark A; Myers, Catherine E

    2013-02-01

    A recurrent-network model provides a unified account of the hippocampal region in mediating the representation of temporal information in classical eyeblink conditioning. Much empirical research is consistent with a general conclusion that delay conditioning (in which the conditioned stimulus CS and unconditioned stimulus US overlap and co-terminate) is independent of the hippocampal system, while trace conditioning (in which the CS terminates before US onset) depends on the hippocampus. However, recent studies show that, under some circumstances, delay conditioning can be hippocampal-dependent and trace conditioning can be spared following hippocampal lesion. Here, we present an extension of our prior trial-level models of hippocampal function and stimulus representation that can explain these findings within a unified framework. Specifically, the current model includes adaptive recurrent collateral connections that aid in the representation of intra-trial temporal information. With this model, as in our prior models, we argue that the hippocampus is not specialized for conditioned response timing, but rather is a general-purpose system that learns to predict the next state of all stimuli given the current state of variables encoded by activity in recurrent collaterals. As such, the model correctly predicts that hippocampal involvement in classical conditioning should be critical not only when there is an intervening trace interval, but also when there is a long delay between CS onset and US onset. Our model simulates empirical data from many variants of classical conditioning, including delay and trace paradigms in which the length of the CS, the inter-stimulus interval, or the trace interval is varied. Finally, we discuss model limitations, future directions, and several novel empirical predictions of this temporal processing model of hippocampal function and learning.

  18. Classic conditioning in aged rabbits: delay, trace, and long-delay conditioning.

    Science.gov (United States)

    Solomon, P R; Groccia-Ellison, M E

    1996-06-01

    Young (0.5 years) and aged (2+, 3+, and 4+ years) rabbits underwent acquisition of the classically conditioned nictitating membrane response in a delay (500-ms conditioned stimulus [CS], 400-ms interstimulus interval [ISI]), long-delay (1,000-ms CS, 900-ms ISI), or trace (500-ms CS, 400-ms stimulus-free period) paradigm. Collapsing across age groups, there is a general tendency for animals to acquire trace conditioning more slowly than delay conditioning. Collapsing across conditioning paradigms, there is a general tendency for aged animals to acquire more slowly than younger animals. Of greater significance, however, are the age differences in the different conditioning paradigms. In the delay and long-delay paradigms, significant conditioning deficits first appeared in the 4(+)-year-old group. In the trace conditioning paradigm, significant conditioning deficits became apparent in the 2(+)-year-old animals.

  19. Oscillatority Conditions for Nonlinear Systems with Delay

    Directory of Open Access Journals (Sweden)

    Denis V. Efimov

    2007-01-01

    Full Text Available Sufficient conditions for oscillatority in the sense of Yakubovich for a class of time delay nonlinear systems are proposed. Under proposed conditions, upper and lower bounds for oscillation amplitude are given. Examples illustrating analytical results by computer simulation are presented.

  20. Comparison research of the classical eyeblink conditioning in guinea pig induced by visual and auditory circle%视觉与听觉通路诱导的豚鼠眨眼条件反射的比较研究

    Institute of Scientific and Technical Information of China (English)

    范郑丽; 隋建峰; 李蕊; 万子兵; 赵红梅

    2009-01-01

    目的 以眼肌电记录法分别记录豚鼠以声音和光信号作为条件刺激(CS)的眨眼条件反射(CR),分析并比较其习得规律.方法 采用金属电极埋植技术及简易"随动"气流给气刺激装置,分别以声音和光信号作为条件刺激(CS),以气流作为非条件刺激(US),以眼肌电信号判断其眨眼行为,在清醒无制动的豚鼠上进行经典眨眼条件反射的训练.结果 在豚鼠内眦采集并记录到眨眼肌电信号显示,声音条件刺激组在第1天、第4天、第7天、第10天的CR习得率分别为(5.0±1.09)%、(31.0±2.09)%、(61.33±1.63)%、(82.33±1.63)%,而光条件刺激组在第1天、第4天、第7天、第10天的CR习得率分别为(5.5±4.59)%、(4.33±3.14)%、(10.83±13.42)%、(3.83±1.33)%,2组CR习得率差异有显著性(P<0.05).结论 以声音作为条件刺激时豚鼠能够成功建立的眨眼条件反射,而以光作为条件刺激时眨眼条件反射的建立却非常困难.%Objective To record the classical eyeblink conditioning single,which the conditioned stimu-lus(CS) is tone or light, by the electromyographic (EMG) of musculi oculi recording. Methods Adopting metal electrode embedding technic and simple air puff stimulus facility ,tone or light as the conditioned stimulus(CS) was paired with air puff being unconditioned stimulus(US) to establish classical eyeblink conditioning of conscious un-fixed guinea pigs. The eyeblink behavior were evaluated through EMG of musculi oculi. Results The eyeblink EMG signal of musculi oculi showed: when the tone as the CS , the results indicated that the acquisition rate of the 1st,the 4th,the 7th,the 10th day were respectively (5.0±1.09)%,(31.0±2.09)%,(61.33±1.63)%,(82.33±1.63) % ; when the light as the CS , the results indicate that the acquisition rate of the 1 st, the 4th, the 7th, the 10th day were respectively (5.5±4.59) %, (4.33±3.14) %, (10.83±13.42)%, (3.83±1.33 ) %. Conclu-sion While CS is tone,classical eyeblink

  1. Delay differential equations with homogeneous integral conditions

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    Abdur Raheem

    2013-03-01

    Full Text Available In this article we prove the existence and uniqueness of a strong solution of a delay differential equation with homogenous integral conditions using the method of semidiscretization in time. As an application, we include an example that illustrates the main result.

  2. Detecting deception via eyeblink frequency modulation

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    Brandon S. Perelman

    2014-02-01

    Full Text Available To assess the efficacy of using eyeblink frequency modulation to detect deception about a third party, 32 participants were sent on a mission to deliver a package to an interviewer. 17 of the participants lied to the interviewer about the details of their mock mission and 15 responded truthfully. During the interview, eyeblink frequency data were collected via electromyography and recorded video. Liars displayed eyeblink frequency suppression while lying, while truth tellers exhibited an increase in eyeblink frequency during the mission relevant questioning period. The compensatory flurry of eyeblinks following deception observed in previous studies was absent in the present study. A discriminant function using eyeblink suppression to predict lying correctly classified 81.3% of cases, with a sensitivity of 88.2% and a specificity of 73.3%. This technique, yielding a reasonable sensitivity, shows promise for future testing as, unlike polygraph, it is compatible with distance technology.

  3. Do long delay conditioned stimuli develop inhibitory properties?

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    Martha eEscobar

    2015-10-01

    Full Text Available In long-delay conditioning, a long conditioned stimulus (CS is paired in its final segments with an unconditioned stimulus. With sufficient training, this procedure usually results in conditioned responding being delayed until the final segment of the CS, a pattern of responding known as inhibition of delay. However, there have been no systematic investigations of the associative structure of long delay conditioning, and whether the initial segment of a long delay CS actually becomes inhibitory is debatable. In an appetitive preparation with rat subjects, the initial segment of long delay CS A passed a retardation (Experiment 1a but not a summation (Experiment 1b test for conditioned inhibition. Furthermore, retardation was observed only if long delay conditioning and retardation training occurred in the same context (Experiment 2. Thus, the initial segment of a long delay CS appears to share more characteristics with a latent inhibitor than a conditioned inhibitor. Componential theories of conditioning appear best suited to account for these results.

  4. Improving Delay-Range-Dependent Stability Condition for Systems with Interval Time-Varying Delay

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    Wei Qian

    2013-01-01

    Full Text Available This paper discusses the delay-range-dependent stability for systems with interval time-varying delay. Through defining the new Lyapunov-Krasovskii functional and estimating the derivative of the LKF by introducing new vectors, using free matrices and reciprocally convex approach, the new delay-range-dependent stability conditions are obtained. Two well-known examples are given to illustrate the less conservatism of the proposed theoretical results.

  5. New Stability Conditions for Linear Differential Equations with Several Delays

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    Leonid Berezansky

    2011-01-01

    Full Text Available New explicit conditions of asymptotic and exponential stability are obtained for the scalar nonautonomous linear delay differential equation x˙(t+∑k=1mak(tx(hk(t=0 with measurable delays and coefficients. These results are compared to known stability tests.

  6. A long-range, wide field-of-view infrared eyeblink detector.

    Science.gov (United States)

    Ryan, Steven B; Detweiler, Krystal L; Holland, Kyle H; Hord, Michael A; Bracha, Vlastislav

    2006-04-15

    Classical conditioning of the eyeblink response in the rabbit is one of the most advanced models of learning and memory in the mammalian brain. Successful use of the eyeblink conditioning paradigm requires precise measurements of the eyeblink response. One common technique of eyelid movement detection utilizes measurements of infrared (IR) light reflected from the surface of the eye. The performance of current IR sensors, however, is limited by their sensitivity to ambient infrared noise, by their small field-of-view and by short working distances. To address these limitations, we developed an IR eyeblink detector consisting of a pulsing (62.5 kHz) IR light emitting diode (LED) paired with a silicon IR photodiode and circuit that synchronously demodulates the recorded signal and rejects background IR noise. The working distance of the sensor exceeds 20 mm, and the field-of-view is larger than the area of a rabbit's eye. Due to its superior characteristics, the new sensor is ideally suited for both standard eyeblink conditioning and for studies that utilize IR-containing visual stimuli and/or that are conducted in an environment contaminated with IR noise.

  7. GLOBAL ASYMPTOTIC STABILITY CONDITIONS OF DELAYED NEURAL NETWORKS

    Institute of Scientific and Technical Information of China (English)

    ZHOU Dong-ming; CAO Jin-de; ZHANG Li-ming

    2005-01-01

    Utilizing the Liapunov functional method and combining the inequality of matrices technique to analyze the existence of a unique equilibrium point and the global asymptotic stability for delayed cellular neural networks (DCNNs), a new sufficient criterion ensuring the global stability of DCNNs is obtained. Our criteria provide some parameters to appropriately compensate for the tradeoff between the matrix definite condition on feedback matrix and delayed feedback matrix. The criteria can easily be used to design and verify globally stable networks. Furthermore, the condition presented here is independent of the delay parameter and is less restrictive than that given in the references.

  8. Delayed effects of cortisol enhance fear memory of trace conditioning.

    Science.gov (United States)

    Cornelisse, Sandra; van Ast, Vanessa A; Joëls, Marian; Kindt, Merel

    2014-02-01

    Corticosteroids induce rapid non-genomic effects followed by slower genomic effects that are thought to modulate cognitive function in opposite and complementary ways. It is presently unknown how these time-dependent effects of cortisol affect fear memory of delay and trace conditioning. This distinction is of special interest because the neural substrates underlying these types of conditioning may be differently affected by time-dependent cortisol effects. Delay conditioning is predominantly amygdala-dependent, while trace conditioning additionally requires the hippocampus. Here, we manipulated the timing of cortisol action during acquisition of delay and trace fear conditioning, by randomly assigning 63 men to one of three possible groups: (1) receiving 10mg hydrocortisone 240 min (slow cort) or (2) 60 min (rapid cort) before delay and trace acquisition, or (3) placebo at both times, in a double-blind design. The next day, we tested memory for trace and delay conditioning. Fear potentiated startle responses, skin conductance responses and unconditioned stimulus expectancy scores were measured throughout the experiment. The fear potentiated startle data show that cortisol intake 240 min before actual fear acquisition (slow cort) uniquely strengthened subsequent trace conditioned memory. No effects of cortisol delivery 60 min prior to fear acquisition were found on any measure of fear memory. Our findings emphasize that slow, presumably genomic, but not more rapid effects of corticosteroids enhance hippocampal-dependent fear memories. On a broader level, our findings underline that basic experimental research and clinically relevant pharmacological treatments employing corticosteroids should acknowledge the timing of corticosteroid administration relative to the learning phase, or therapeutic intervention.

  9. Delayed effects of cortisol enhance fear memory of trace conditioning

    NARCIS (Netherlands)

    Cornelisse, S.; Ast, V.A. van; Joëls, M.; Kindt, M.

    2014-01-01

    Corticosteroids induce rapid non-genomic effects followed by slower genomic effects that are thought to modulate cognitive function in opposite and complementary ways. It is presently unknown how these time-dependent effects of cortisol affect fear memory of delay and trace conditioning. This distin

  10. Delayed effects of cortisol enhance fear memory of trace conditioning

    NARCIS (Netherlands)

    Cornelisse, S.; Ast, V.A. van; Joëls, M.; Kindt, M.

    2014-01-01

    Corticosteroids induce rapid non-genomic effects followed by slower genomic effects that are thought to modulate cognitive function in opposite and complementary ways. It is presently unknown how these time-dependent effects of cortisol affect fear memory of delay and trace conditioning. This distin

  11. The search for the engram in eyeblink conditioning: A synopsis of past and present perspectives on the role of the cerebellum.

    Science.gov (United States)

    Foy, Michael R; Foy, Judith G

    2016-12-01

    One of the most prolific behavioral neuroscientists of his generation, Richard F. Thompson published more than 450 research articles during his almost 60-year career before his death in 2014. The breadth and reach of his scholarship has extended to a large multidisciplinary audience of scientists. The focal point of this article is arguably his most influential paper on cerebellar classical conditioning entitled "The Neurobiology of Learning and Memory" that appeared in Science in 1986 and has been cited 700 times since its publication. Here, a summary of the initial Thompson laboratory research leading up to an understanding of the cerebellum and its critical role in memory traces will be discussed, along with conclusions from the Science article pertinent to cerebellar classical conditioning. The summary will also discuss how the original 1986 article continues to stimulate and influence new research and provide further insights into the role of the cerebellum in the neurobiology of learning and memory function relevant to studies of mammalian classical conditioning. (PsycINFO Database Record

  12. The nicotinic agonist RJR-2403 compensates the impairment of eyeblink conditioning produced by the noncompetitive NMDA-receptor antagonist MK-801.

    Science.gov (United States)

    Rodríguez-Moreno, Antonio; Carrión, Miriam; Delgado-García, José María

    2006-07-10

    The classical conditioning of eyelid responses using trace paradigms is a hippocampal-related model of associative learning, involving the activation of N-methyl-D-aspartate (NMDA) receptors. We have evaluated here the effects of NMDA-receptor blockage with the selective noncompetitive antagonist (5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine hydrogen maleate (dizocilpine, MK-801). Mice were implanted with stimulating electrodes on the supraorbitary nerve and with recording electrodes in the ipsilateral orbicularis oculi muscle. Animals were conditioned with a trace shock-SHOCK paradigm. MK-801-injected animals (0.02 mg/kg) seemed unable to acquire this type of associative learning task, but the latency and amplitude of their unconditioned eyelid responses was not affected by drug administration. The administration of the nicotinic agonist (E)-N-methyl-4-(3-pyridinyl)-3-buten-1-amine (RJR-2403; 2 mg/kg) was able to restore completely the acquisition of the conditioned response when administered both before and after MK-801. In vitro recordings of field excitatory postsynaptic potentials (fEPSPs) evoked in the hippocampal CA1 area by the electrical stimulation of the Schaffer collateral pathway indicates that RJR-2403 application to the bath enhance the release of glutamate by a presynaptic mechanism. These findings reveal that nicotinic acetylcholine receptors enhance glutamatergic transmission in hippocampal circuits involved in the acquisition of associative learning.

  13. Tropospheric Delay Analysis Based on Some Chinese Cities' Meteorologic Conditions

    Science.gov (United States)

    Liu, Q.; Chen, X. H.; Sun, J. Z.; Han, B. B.; Zhang, Q.

    2014-03-01

    With the increase of the users' precision in satellite orientation and navigation, the influence of the tropospheric delay has become increasingly vital, which needs to be corrected. The paper contrastively analyzes some main mapping functions' models of the tropospheric delay theory. It discusses the distributions of the hydrostatic/wet mapping functions of Niell Mapping Function (NMF), Vienna Mapping Function 1 (VMF1), and Global Mapping Function (GMF). And it analyzes tropospheric delay based on the meteorologic conditions in some Chinese cities. It could be concluded from the results that the hydrostatic VMF1 and GMF are in yearly periodic cosine distributions and approximately identical, whereas the hydrostatic NMF is roughly larger than the formers. The wet VMF1, which is influenced greatly by the atmosphere, displays close to cosine functions. Besides, VMF1 and GMF roughly display minimum in summer and maximum in winter, respectively. While the elevation angle is 10 degrees, the Slant Propagation Delays (SPDs) of the chosen stations are all in yearly periodic cosine distributions, and they decrease with the increase of the latitude. The SPD reaches maximum in summer and minimum in winter, and the difference is about 2 m.

  14. Sharp conditions for the oscillation of delay difference equations

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    G. Ladas

    1989-01-01

    Full Text Available Suppose that {pn} is a nonnegative sequence of real numbers and let k be a positive integer. We prove that limn→∞inf [1k∑i=n−kn−1pi]>kk(k+1k+1 is a sufficient condition for the oscillation of all solutions of the delay difference equation An+1−An+pnAn−k=0,   n=0,1,2,…. This result is sharp in that the lower bound kk/(k+1k+1 in the condition cannot be improved. Some results on difference inequalities and the existence of positive solutions are also presented.

  15. A new delay-independent condition for global robust stability of neural networks with time delays.

    Science.gov (United States)

    Samli, Ruya

    2015-06-01

    This paper studies the problem of robust stability of dynamical neural networks with discrete time delays under the assumptions that the network parameters of the neural system are uncertain and norm-bounded, and the activation functions are slope-bounded. By employing the results of Lyapunov stability theory and matrix theory, new sufficient conditions for the existence, uniqueness and global asymptotic stability of the equilibrium point for delayed neural networks are presented. The results reported in this paper can be easily tested by checking some special properties of symmetric matrices associated with the parameter uncertainties of neural networks. We also present a numerical example to show the effectiveness of the proposed theoretical results.

  16. Approximate Solutions of Delay Parabolic Equations with the Dirichlet Condition

    Directory of Open Access Journals (Sweden)

    Deniz Agirseven

    2012-01-01

    Full Text Available Finite difference and homotopy analysis methods are used for the approximate solution of the initial-boundary value problem for the delay parabolic partial differential equation with the Dirichlet condition. The convergence estimates for the solution of first and second orders of difference schemes in Hölder norms are obtained. A procedure of modified Gauss elimination method is used for the solution of these difference schemes. Homotopy analysis method is applied. Comparison of finite difference and homotopy analysis methods is given on the problem.

  17. Eyeblink Synchrony in Multimodal Human-Android Interaction.

    Science.gov (United States)

    Tatsukawa, Kyohei; Nakano, Tamami; Ishiguro, Hiroshi; Yoshikawa, Yuichiro

    2016-12-23

    As the result of recent progress in technology of communication robot, robots are becoming an important social partner for humans. Behavioral synchrony is understood as an important factor in establishing good human-robot relationships. In this study, we hypothesized that biasing a human's attitude toward a robot changes the degree of synchrony between human and robot. We first examined whether eyeblinks were synchronized between a human and an android in face-to-face interaction and found that human listeners' eyeblinks were entrained to android speakers' eyeblinks. This eyeblink synchrony disappeared when the android speaker spoke while looking away from the human listeners but was enhanced when the human participants listened to the speaking android while touching the android's hand. These results suggest that eyeblink synchrony reflects a qualitative state in human-robot interactions.

  18. Naloxone induces multiple effects on aversive Pavlovian conditioning in rabbits.

    Science.gov (United States)

    Hernández, L L; Powell, D A

    1983-06-01

    A series of experiments examined the effects of intravenous naloxone treatment on aversive Pavlovian conditioning of eye-blink and heart rate responses, and related unconditioned behaviors, in rabbits. Naloxone treatment before testing attenuated bradycardiac orienting responses to tones used as conditioning stimuli. Naloxone also attenuated conditioned bradycardia when administered either before or after training sessions, but it potentiated conditioned bradycardia during extinction of discriminative conditioning. Naloxone did not influence acquisition or extinction of discriminative eye-blink conditioning or somatic or cardiac responses to shocks used as unconditioned stimuli, but it did decrease locomotor activity. Naloxone treatment immediately after training sessions facilitated acquisition of eye-blink responses. It was concluded that naloxone influences aversive Pavlovian conditioning in more than one way: (a) During training, it appears to alter reception and processing of signals but does not affect subsequent development of somatic responses to the Pavlovian conditioning contingency. (b) After training sessions, naloxone apparently affects consolidation of both somatic and autonomic conditioning. (c) Naloxone also appears to delay extinction of Pavlovian conditioning; this effect may similarly involve changes in a stimulus-processing mechanism or in memory functions, but it apparently does not involve changes in somatomotor responsitivity.

  19. Delay Analysis and Formulation Inference of Signalized Intersection for Traffic Congestion Conditions

    Institute of Scientific and Technical Information of China (English)

    刘广萍; 丁建梅

    2004-01-01

    Vehicle delay is an important measure to evaluate the signal timings of signalized intersections.When optimization the signal control parameters, delays of vehicles from all approach directions of an intersection should be considered. Based on the analysis of the vehicle delay on an approach of intersection, directed against the typical condition of a congested intersection-over-saturated condition, the paper has analyzed and inferred the intersection delay dynamic formulation, and has established the relation between intersection delay,the signal timings, vehicle arrival rate and the queue lengths, and that provides useful information for understanding vehicle delay of signalized intersection and for establishing performance index function of signal timing optimization.

  20. More relaxed condition for dynamics of discrete time delayed Hopfield neural networks

    Institute of Scientific and Technical Information of China (English)

    Zhang Qiang

    2008-01-01

    The dynamics of discrete time delayed Hopfield neural networks is investigated.By using a difference inequality combining with the linear matrix inequality,a sufficient condition ensuring global exponential stability of the unique equilibrium point of the networks is found.The result obtained holds not only for constant delay but also for time-varying delays.

  1. Modeling startle eyeblink electromyogram to assess fear learning.

    Science.gov (United States)

    Khemka, Saurabh; Tzovara, Athina; Gerster, Samuel; Quednow, Boris B; Bach, Dominik R

    2017-02-01

    Pavlovian fear conditioning is widely used as a laboratory model of associative learning in human and nonhuman species. In this model, an organism is trained to predict an aversive unconditioned stimulus from initially neutral events (conditioned stimuli, CS). In humans, fear memory is typically measured via conditioned autonomic responses or fear-potentiated startle. For the latter, various analysis approaches have been developed, but a systematic comparison of competing methodologies is lacking. Here, we investigate the suitability of a model-based approach to startle eyeblink analysis for assessment of fear memory, and compare this to extant analysis strategies. First, we build a psychophysiological model (PsPM) on a generic startle response. Then, we optimize and validate this PsPM on three independent fear-conditioning data sets. We demonstrate that our model can robustly distinguish aversive (CS+) from nonaversive stimuli (CS-, i.e., has high predictive validity). Importantly, our model-based approach captures fear-potentiated startle during fear retention as well as fear acquisition. Our results establish a PsPM-based approach to assessment of fear-potentiated startle, and qualify previous peak-scoring methods. Our proposed model represents a generic startle response and can potentially be used beyond fear conditioning, for example, to quantify affective startle modulation or prepulse inhibition of the acoustic startle response. © 2016 The Authors. Psychophysiology published by Wiley Periodicals, Inc. on behalf of Society for Psychophysiological Research.

  2. Simple stability conditions of linear discrete time systems with multiple delay

    Directory of Open Access Journals (Sweden)

    Stojanović Sreten B.

    2010-01-01

    Full Text Available In this paper we have established a new Lyapunov-Krasovskii method for linear discrete time systems with multiple time delay. Based on this method, two sufficient conditions for delay-independent asymptotic stability of the linear discrete time systems with multiple delays are derived in the shape of Lyapunov inequality. Numerical examples are presented to demonstrate the applicability of the present approach.

  3. Double dissociation of amygdala and hippocampal contributions to trace and delay fear conditioning.

    Science.gov (United States)

    Raybuck, Jonathan D; Lattal, K Matthew

    2011-01-19

    A key finding in studies of the neurobiology of learning memory is that the amygdala is critically involved in Pavlovian fear conditioning. This is well established in delay-cued and contextual fear conditioning; however, surprisingly little is known of the role of the amygdala in trace conditioning. Trace fear conditioning, in which the CS and US are separated in time by a trace interval, requires the hippocampus and prefrontal cortex. It is possible that recruitment of cortical structures by trace conditioning alters the role of the amygdala compared to delay fear conditioning, where the CS and US overlap. To investigate this, we inactivated the amygdala of male C57BL/6 mice with GABA (A) agonist muscimol prior to 2-pairing trace or delay fear conditioning. Amygdala inactivation produced deficits in contextual and delay conditioning, but had no effect on trace conditioning. As controls, we demonstrate that dorsal hippocampal inactivation produced deficits in trace and contextual, but not delay fear conditioning. Further, pre- and post-training amygdala inactivation disrupted the contextual but the not cued component of trace conditioning, as did muscimol infusion prior to 1- or 4-pairing trace conditioning. These findings demonstrate that insertion of a temporal gap between the CS and US can generate amygdala-independent fear conditioning. We discuss the implications of this surprising finding for current models of the neural circuitry involved in fear conditioning.

  4. Surface electromyography recording of spontaneous eyeblinks: applications in neuroprosthetics.

    Science.gov (United States)

    Frigerio, Alice; Brenna, Stefano; Cavallari, Paolo

    2013-02-01

    We are designing an implantable neuroprosthesis for the treatment of unilateral facial paralysis. The envisioned biomimetic device paces artificial blinks in the paretic eyelid when activity in the healthy orbicularis oculi (orbicularis) muscle is detected. The present article focuses on electromyography (EMG)-based eyeblink detection. A pilot clinical study was performed in healthy volunteers who were intended to represent individuals with facial paralysis. Spontaneous eyeblinks were detected by a surface EMG recording. Blink detection accuracy was tested at rest and during voluntary smiling and chewing. Fifteen participants were asked to wear surface recording electrodes on the left side of their face, detecting the orbicularis oculi, the masseter, and the zygomatic muscle EMG activity. Participants were asked to look ahead, voluntarily smile, and chew according to an experimental protocol. Custom software was designed with the purpose of selectively filtering the multichannel EMG recordings and triggering a digital output. The software filter allowed elimination of spurious artificial eyeblinks and thus increased the accuracy of the EMG recording apparatus for the spontaneous blinking. Orbicularis oculi EMG recording worked as a real-time eyeblink-detecting system. Moreover, the multichannel EMG recording coupled to a proper digital signal processing was very effective in specifically detecting the spontaneous blinking during other facial muscle activities. With regard to closed-loop biomimetic devices for the pacing of the eyeblink, the EMG signal represents a valid option for the recording side.

  5. Differential acetylcholine release in the prefrontal cortex and hippocampus during pavlovian trace and delay conditioning.

    Science.gov (United States)

    Flesher, M Melissa; Butt, Allen E; Kinney-Hurd, Brandee L

    2011-09-01

    Pavlovian trace conditioning critically depends on the medial prefrontal cortex (mPFC) and hippocampus (HPC), whereas delay conditioning does not depend on these brain structures. Given that the cholinergic basal forebrain system modulates activity in both the mPFC and HPC, it was reasoned that the level of acetylcholine (ACh) release in these regions would show distinct profiles during testing in trace and delay conditioning paradigms. To test this assumption, microdialysis probes were implanted unilaterally into the mPFC and HPC of rats that were pre-trained in appetitive trace and delay conditioning paradigms using different conditional stimuli in the two tasks. On the day of microdialysis testing, dialysate samples were collected during a quiet baseline interval before trials were initiated, and again during performance in separate blocks of trace and delay conditioning trials in each animal. ACh levels were quantified using high-performance liquid chromatography and electrochemical detection techniques. Consistent with our hypothesis, results showed that ACh release in the mPFC was greater during trace conditioning than during delay conditioning. The level of ACh released during trace conditioning in the HPC was also greater than the levels observed during delay conditioning. While ACh efflux in both the mPFC and HPC selectively increased during trace conditioning, ACh levels in the mPFC during trace conditioning testing showed the greatest increases observed. These results demonstrate a dissociation in cholinergic activation of the mPFC and HPC during performance in trace but not delay appetitive conditioning, where this cholinergic activity may contribute to attentional mechanisms, adaptive response timing, or memory consolidation necessary for successful trace conditioning.

  6. NECESSARY AND SUFFICIENT CONDITIONS FOR OSCILLATIONS OF NEUTRAL HYPERBOLIC PARTIAL DIFFERENTIAL EQUATIONS WITH DELAYS

    Institute of Scientific and Technical Information of China (English)

    Yang Jun; Wang Chunyan; Li Jing; Meng Zhijuan

    2006-01-01

    This paper is concerned with the oscillations of neutral hyperbolic partial differential equations with delays. Necessary and sufficient conditions are obtained for the oscillations of all solutions of the equations, and these results are illustrated by some examples.

  7. Explicit Conditions for Stability of Nonlinear Scalar Delay Impulsive Difference Equation

    Directory of Open Access Journals (Sweden)

    Bo Zheng

    2010-01-01

    Full Text Available Sufficient conditions are obtained for the uniform stability and global attractivity of the zero solution of nonlinear scalar delay impulsive difference equation, which extend and improve the known results in the literature. An example is also worked out to verify that the global attractivity condition is a sharp condition.

  8. Toward an understanding of the emotion-modulated startle eyeblink reflex: the case of anger.

    Science.gov (United States)

    Peterson, Carly K; Harmon-Jones, Eddie

    2012-11-01

    Three studies investigated the effect of angering pictures on the startle eyeblink response, based on anger's unique identity as an approach-oriented negative affect. In Study 1, eyeblinks to startling noise probes during angering and neutral pictures did not differ, despite angering pictures being rated higher on arousal and anger and more negative in valence. Study 2 replicated Study 1; also, dysphoric participants exhibited potentiated eyeblinks to probes during angering pictures much like those to probes during fear/disgust stimuli. A follow-up study revealed that dysphoric participants rated angering pictures higher in fear. Study 3 again found that eyeblinks to probes during angering and neutral pictures did not differ. Taken together, these results suggest that probes during angering stimuli elicit eyeblinks much like those during neutral stimuli, perhaps due to the competing influences of arousal, valence, and motivation on the startle eyeblink reflex.

  9. Effects of natural gas composition on ignition delay under diesel conditions

    Science.gov (United States)

    Naber, J. D.; Siebers, D. L.; Dijulio, S. S.; Westbrook, C. K.

    1993-12-01

    Effects of variations in natural gas composition on autoignition of natural gas under direct-injection (DI) diesel engine conditions were studied experimentally in a constant-volume combustion vessel and computationally using a chemical kinetic model. Four fuel blends were investigated: pure methane, a capacity weighted mean natural gas, a high ethane content natural gas, and a natural gas with added propane typical of peak shaving conditions. Experimentally measured ignition delays were longest for pure methane and became progressively shorter as ethane and propane concentrations increased. At conditions characteristic of a DI compression ignition natural gas engine at Top Dead Center (CR = 23:1, p = 6.8 MPa, T = 1150K), measured ignition delays for the four fuels varied from 1.8 ms for the peak shaving and high ethane gases to 2.7 ms for pure methane. Numerically predicted variations in ignition delay as a function of natural gas composition agreed with these measurements.

  10. Data-driven modeling of systemic delay propagation under severe meteorological conditions

    CERN Document Server

    Fleurquin, Pablo; Eguiluz, Victor M

    2013-01-01

    The upsetting consequences of weather conditions are well known to any person involved in air transportation. Still the quantification of how these disturbances affect delay propagation and the effectiveness of managers and pilots interventions to prevent possible large-scale system failures needs further attention. In this work, we employ an agent-based data-driven model developed using real flight performance registers for the entire US airport network and focus on the events occurring on October 27 2010 in the United States. A major storm complex that was later called the 2010 Superstorm took place that day. Our model correctly reproduces the evolution of the delay-spreading dynamics. By considering different intervention measures, we can even improve the model predictions getting closer to the real delay data. Our model can thus be of help to managers as a tool to assess different intervention measures in order to diminish the impact of disruptive conditions in the air transport system.

  11. Effects of meditation practice on spontaneous eyeblink rate.

    Science.gov (United States)

    Kruis, Ayla; Slagter, Heleen A; Bachhuber, David R W; Davidson, Richard J; Lutz, Antoine

    2016-05-01

    A rapidly growing body of research suggests that meditation can change brain and cognitive functioning. Yet little is known about the neurochemical mechanisms underlying meditation-related changes in cognition. Here, we investigated the effects of meditation on spontaneous eyeblink rates (sEBR), a noninvasive peripheral correlate of striatal dopamine activity. Previous studies have shown a relationship between sEBR and cognitive functions such as mind wandering, cognitive flexibility, and attention-functions that are also affected by meditation. We therefore expected that long-term meditation practice would alter eyeblink activity. To test this, we recorded baseline sEBR and intereyeblink intervals (IEBI) in long-term meditators (LTM) and meditation-naive participants (MNP). We found that LTM not only blinked less frequently, but also showed a different eyeblink pattern than MNP. This pattern had good to high degree of consistency over three time points. Moreover, we examined the effects of an 8-week course of mindfulness-based stress reduction on sEBR and IEBI, compared to an active control group and a waitlist control group. No effect of short-term meditation practice was found. Finally, we investigated whether different types of meditation differentially alter eyeblink activity by measuring sEBR and IEBI after a full day of two kinds of meditation practices in the LTM. No effect of meditation type was found. Taken together, these findings may suggest either that individual difference in dopaminergic neurotransmission is a self-selection factor for meditation practice, or that long-term, but not short-term meditation practice induces stable changes in baseline striatal dopaminergic functioning.

  12. Lasing oscillation condition and group delay control in gain-assisted plasmon-induced transparency

    CERN Document Server

    Deng, Zi-Lan; Wang, He-Zhou; Cheng, S H; Li, Jensen

    2012-01-01

    A gain-assisted plasmonic waveguide with two detuned resonators is investigated in the plasmon-induced transparency window. Phase map is employed to study power transmittance and group delay for varying gain coefficients and frequency detunings of the two resonators. The gain coefficient for lasing oscillation condition is analytically shown to vary quadratically with the frequency detuning. In the amplification regime below the lasing threshold, the spectrum implies not only large group delay, but also high transmittance and narrow linewidth. This is in contrast to those in the loss-compensation regime and the passive case in which there always exists a trade-off between the linewidth and the peak transmittance.

  13. A Stability Condition with Delay-Dependence for a Class of Switched Large-Scale Time-Delay Systems

    Directory of Open Access Journals (Sweden)

    Chi-Jo Wang

    2013-01-01

    Full Text Available By using the time-switched method and the comparison theorem, we derived a criterion of delay-dependent stability for the switched large-scale time-delay systems. To guarantee the exponential stability for the switched large-scale time-delay systems with stability margin λ, the total activation time ratio of the switching law is determined. An example is used to illustrate the effectiveness of our result.

  14. Dorsal hippocampal lesions disrupt Pavlovian delay conditioning and conditioned-response timing.

    Science.gov (United States)

    Tam, Shu K E; Bonardi, Charlotte

    2012-04-21

    The involvement of the rat dorsal hippocampus (dhpc) in Pavlovian conditioning and timing of conditioned responding was examined in an appetitive preparation in which presentation of a relatively long, 40-s auditory conditioned stimulus (CS) was followed immediately by food delivery. Dorsal hippocampal lesions impaired Pavlovian conditioning in this task. They also produced a deficit in interval timing, replicating previous findings with short CSs. The conditioning and timing deficits observed are consistent with the findings from single-unit recording studies in other species, and suggest that the involvement of the dhpc in Pavlovian processes could be more general than is assumed by many of the current theories of hippocampal function.

  15. Dynamic stability conditions for Lotka-Volterra recurrent neural networks with delays.

    Science.gov (United States)

    Yi, Zhang; Tan, K K

    2002-07-01

    The Lotka-Volterra model of neural networks, derived from the membrane dynamics of competing neurons, have found successful applications in many "winner-take-all" types of problems. This paper studies the dynamic stability properties of general Lotka-Volterra recurrent neural networks with delays. Conditions for nondivergence of the neural networks are derived. These conditions are based on local inhibition of networks, thereby allowing these networks to possess a multistability property. Multistability is a necessary property of a network that will enable important neural computations such as those governing the decision making process. Under these nondivergence conditions, a compact set that globally attracts all the trajectories of a network can be computed explicitly. If the connection weight matrix of a network is symmetric in some sense, and the delays of the network are in L2 space, we can prove that the network will have the property of complete stability.

  16. Short-term total sleep deprivation alters delay-conditioned memory in the rat.

    Science.gov (United States)

    Tripathi, Shweta; Jha, Sushil K

    2016-06-01

    Short-term sleep deprivation soon after training may impair memory consolidation. Also, a particular sleep stage or its components increase after learning some tasks, such as negative and positive reinforcement tasks, avoidance tasks, and spatial learning tasks, and so forth. It suggests that discrete memory types may require specific sleep stage or its components for their optimal processing. The classical conditioning paradigms are widely used to study learning and memory but the role of sleep in a complex conditioned learning is unclear. Here, we have investigated the effects of short-term sleep deprivation on the consolidation of delay-conditioned memory and the changes in sleep architecture after conditioning. Rats were trained for the delay-conditioned task (for conditioning, house-light [conditioned stimulus] was paired with fruit juice [unconditioned stimulus]). Animals were divided into 3 groups: (a) sleep deprived (SD); (b) nonsleep deprived (NSD); and (c) stress control (SC) groups. Two-way ANOVA revealed a significant interaction between groups and days (training and testing) during the conditioned stimulus-unconditioned stimulus presentation. Further, Tukey post hoc comparison revealed that the NSD and SC animals exhibited significant increase in performances during testing. The SD animals, however, performed significantly less during testing. Further, we observed that wakefulness and NREM sleep did not change after training and testing. Interestingly, REM sleep increased significantly on both days compared to baseline more specifically during the initial 4-hr time window after conditioning. Our results suggest that the consolidation of delay-conditioned memory is sleep-dependent and requires augmented REM sleep during an explicit time window soon after training. (PsycINFO Database Record

  17. Comparison of eyeblink monitoring and EEG signal analysis for mental fatigue assessment

    Science.gov (United States)

    Królak, Aleksandra; Strumiłło, Paweł

    2008-01-01

    Mental fatigue in humans is a major cause of accidents in occupations requiring constant attention. The most promising indicators of fatigue are eyeblink dynamics and electroencephalography. This paper presents the results of a study aimed at establishing the dependence between eyeblink dynamics and EEG signal changes during transition to mental fatigue.

  18. Impact of the initial tropospheric zenith path delay on precise point positioning convergence during active conditions

    Science.gov (United States)

    Kalita, J. Z.; Rzepecka, Z.

    2017-04-01

    Tropospheric delay is one of the key factors that influence the convergence time of the precise point positioning (PPP) method. Current models do not allow for the fixing of the zenith path delay tropospheric parameter, leaving the difference between nominal and final value to the estimation process. Here, we present an analysis of several PPP result-sets using the tropospheric parameter’s nominal value adopted from models: VMF1, GPT2w, MOPS, and ZERO-WET. The last variant assumes a zero value for the initial wet part of the zenith delay. The PPP results are subtracted from a solution based on the final tropospheric product from the International GNSS Service (IGS). Several days exhibiting the most active tropospheric conditions were selected for each of the 7 stations located in the mid-latitude Central European region. During the active days, application of the VMF1 model increases the resulting height component’s quality by about 33–36% when compared to the GPT2w and MOPS. The respective improvement in VMF1 latitude and longitude components is 27% and 15%. The average relative deterioration in the result standard deviations between active and calm tropospheric conditions reaches about 20–30% of the former. We discuss the impact of the initial tropospheric parameter’s variance and bias on positioning. In addition, we compare the results with those of other studies over the impact of active tropospheric conditions on the PPP method.

  19. A new proposal for drug conditioning with implications for drug addiction: the Pavlovian two-step from delay to trace conditioning.

    Science.gov (United States)

    Carey, Robert J; Carrera, Marinette Pinheiro; Damianopoulos, Ernest N

    2014-12-15

    Pavlovian conditioning of drug effects is generally acknowledged to be a critical factor in the development and persistence of drug addiction. In drug conditioning the focus has essentially been on one type of Pavlovian conditioning, namely, delay conditioning in which the CS and drug UCS overlap and are temporally contiguous. Another type of Pavlovian conditioning is trace-conditioning in which the CS terminates before the onset of the UCS. While trace conditioning has been extensively studied in conditioning studies using a punctual CS and a non-drug UCS, trace conditioning has not been considered as having a role in drug conditioning. In several recent reports we have conducted experiments in which we first established a contextual drug CS using a delay conditioning protocol and subsequently used this same CS in a trace drug conditioning protocol with the same or different drug treatment and showed that the CS could be strongly modified by trace conditioning. These observations take on importance in that it has been well established that delay and trace conditioning are mediated by different CNS systems. Delay conditioning is mediated by cerebellar mechanisms, conforming to the general idea of Pavlovian conditioning as a reflexive type of learning whereas trace conditioning involves the hippocampus and frontal cortex brain structures more commonly associated with voluntary behavior. In this proposal we suggest that the emergence of potent drug associations that motivate drug-seeking behavior and addiction are initiated by delay conditioning and subsequently amplified and linked to higher brain functions by trace conditioning.

  20. Performance in eyeblink conditioning is age and sex dependent

    NARCIS (Netherlands)

    Löwgren, Karolina; Bååth, Rasmus; Rasmussen, Anders; Boele, Henk-Jan; Koekkoek, Sebastiaan K E; De Zeeuw, Chris I; Hesslow, Germund

    2017-01-01

    A growing body of evidence suggests that the cerebellum is involved in both cognition and language. Abnormal cerebellar development may contribute to neurodevelopmental disorders such as attention deficit hyperactivity disorder (ADHD), autism, fetal alcohol syndrome, dyslexia, and specific language

  1. Hippocampal-dependent Pavlovian conditioning in adult rats exposed to binge-like doses of ethanol as neonates.

    Science.gov (United States)

    Lindquist, Derick H

    2013-04-01

    Binge-like postnatal ethanol exposure produces significant damage throughout the brain in rats, including the cerebellum and hippocampus. In the current study, cue- and context-mediated Pavlovian conditioning were assessed in adult rats exposed to moderately low (3E; 3g/kg/day) or high (5E; 5g/kg/day) doses of ethanol across postnatal days 4-9. Ethanol-exposed and control groups were presented with 8 sessions of trace eyeblink conditioning followed by another 8 sessions of delay eyeblink conditioning, with an altered context presented over the last two sessions. Both forms of conditioning rely on the brainstem and cerebellum, while the more difficult trace conditioning also requires the hippocampus. The hippocampus is also needed to gate or modulate expression of the eyeblink conditioned response (CR) based on contextual cues. Results indicate that the ethanol-exposed rats were not significantly impaired in trace EBC relative to control subjects. In terms of CR topography, peak amplitude was significantly reduced by both doses of alcohol, whereas onset latency but not peak latency was significantly lengthened in the 5E rats across the latter half of delay EBC in the original training context. Neither dosage resulted in significant impairment in the contextual gating of the behavioral response, as revealed by similar decreases in CR production across all four treatment groups following introduction of the novel context. Results suggest ethanol-induced brainstem-cerebellar damage can account for the present results, independent of the putative disruption in hippocampal development and function proposed to occur following postnatal ethanol exposure.

  2. An inventory model for deteriorating items under the condition of permissible delay in payments

    Directory of Open Access Journals (Sweden)

    Chang Horng-Jinh

    2002-01-01

    Full Text Available In economic order quantity (EOQ models, it is often assumed that the payment of an order is made on the receipt of items by the inventory system. However, such an assumption is not quite practical in the real world. Under most market behaviors, it can be easily found that a vendor provides a credit period for buyers to stimulate demand. In this paper, a varying rate of determination and the condition of permissible delay in payments used in conjunction with the economic order quantity model are the focus of discussion. Numerical examples are presented to illustrate the proposed models.

  3. Stability of linear multistep methods for delay differential equations in the light of Kreiss resolvent condition

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper deals with the stability analysis of the linear multistep (LM) methods in the numerical solution of delay differential equations. Here we provide a qualitative stability estimates, pertiment to the classical scalar test problem of the form y'(t) = λy(t) + μy(t - τ) with τ > 0 and λ ,μ are complex, by using (vartiant to) the resolvent condition of Kreiss. We prove that for A-stable LM methods the upper bound for the norm of the n -th power of square matrix grows linearly with the order of the matrix.

  4. Stability and Bifurcation in a Delayed Reaction-Diffusion Equation with Dirichlet Boundary Condition

    Science.gov (United States)

    Guo, Shangjiang; Ma, Li

    2016-04-01

    In this paper, we study the dynamics of a diffusive equation with time delay subject to Dirichlet boundary condition in a bounded domain. The existence of spatially nonhomogeneous steady-state solution is investigated by applying Lyapunov-Schmidt reduction. The existence of Hopf bifurcation at the spatially nonhomogeneous steady-state solution is derived by analyzing the distribution of the eigenvalues. The direction of Hopf bifurcation and stability of the bifurcating periodic solution are also investigated by means of normal form theory and center manifold reduction. Moreover, we illustrate our general results by applications to the Nicholson's blowflies models with one- dimensional spatial domain.

  5. Global Stabilization of High-Order Time-Delay Nonlinear Systems under a Weaker Condition

    Directory of Open Access Journals (Sweden)

    Nengwei Zhang

    2014-01-01

    Full Text Available Under the weaker condition on the system growth, this paper further investigates the problem of global stabilization by state feedback for a class of high-order nonlinear systems with time-varying delays. By skillfully using the homogeneous domination approach, a continuous state feedback controller is successfully designed, which preserves the equilibrium at the origin and guarantees the global asymptotic stability of the resulting closed-loop system. A simulation example is given to demonstrate the effectiveness of the proposed design procedure.

  6. Behaviorally inhibited individuals demonstrate significantly enhanced conditioned response acquisition under non-optimal learning conditions.

    Science.gov (United States)

    Holloway, J L; Allen, M T; Myers, C E; Servatius, R J

    2014-03-15

    Behavioral inhibition (BI) is an anxiety vulnerability factor associated with hypervigilance to novel stimuli, threat, and ambiguous cues. The progression from anxiety risk to a clinical disorder is unknown, although the acquisition of defensive learning and avoidance may be a critical feature. As the expression of avoidance is also central to anxiety development, the present study examined avoidance acquisition as a function of inhibited temperament using classical eyeblink conditioning. Individuals were classified as behaviorally inhibited (BI) or non-inhibited (NI) based on combined scores from the Adult and Retrospective Measures of Behavioural Inhibition (AMBI and RMBI, respectively). Acquisition was assessed using delay, omission, or yoked conditioning schedules of reinforcement. Omission training was identical to delay, except that the emission of an eyeblink conditioned response (CR) resulted in omission of the unconditioned airpuff stimulus (US) on that trial. Each subject in the yoked group was matched on total BI score to a subject in the omission group, and received the same schedule of CS and US delivery, resulting in a partial reinforcement training schedule. Delay conditioning elicited significantly more CRs compared to the omission and yoked contingencies, the latter two of which did not differ from each other. Thus, acquisition of an avoidance response was not apparent. BI individuals demonstrated enhanced acquisition overall, while partial reinforcement training significantly distinguished between BI and NI groups. Enhanced learning in BI may be a function of an increased defensive learning capacity, or sensitivity to uncertainty. Further work examining the influence of BI on learning acquisition is important for understanding individual differences in disorder etiology in anxiety vulnerable cohorts.

  7. Immediate Extinction Causes a Less Durable Loss of Performance than Delayed Extinction following Either Fear or Appetitive Conditioning

    Science.gov (United States)

    Woods, Amanda M.; Bouton, Mark E.

    2008-01-01

    Five experiments with rat subjects compared the effects of immediate and delayed extinction on the durability of extinction learning. Three experiments examined extinction of fear conditioning (using the conditioned emotional response method), and two experiments examined extinction of appetitive conditioning (using the food-cup entry method). In…

  8. Global exponential stability conditions for generalized state-space systems with time-varying delays

    Energy Technology Data Exchange (ETDEWEB)

    Yu, K.-W. [Department of Marine Engineering, National Kaohsiung Marine University, Kaohsiung 811, Taiwan (China)], E-mail: kwyu@mail.nkmu.edu.tw; Lien, C.-H. [Department of Marine Engineering, National Kaohsiung Marine University, Kaohsiung 811, Taiwan (China)], E-mail: chlien.ee@msa.hinet.net

    2008-05-15

    A unified approach is proposed to deal with the exponential stability for generalized state-space systems with time-varying delays. Many systems models can be regarded as special cases of the considered systems; such as neutral time-delay systems and delayed cellular neural networks. Delay-dependent stability criteria are proposed to guarantee the global exponential stability for generalized state-space systems with two cases of uncertainties. Two numerical examples are given to show the effectiveness of our method.

  9. Immediate extinction causes a less durable loss of performance than delayed extinction following either fear or appetitive conditioning

    OpenAIRE

    Woods, Amanda M.; Bouton, Mark E.

    2008-01-01

    Five experiments with rat subjects compared the effects of immediate and delayed extinction on the durability of extinction learning. Three experiments examined extinction of fear conditioning (using the conditioned emotional response method), and two experiments examined extinction of appetitive conditioning (using the food-cup entry method). In all experiments, conditioning and extinction were accomplished in single sessions, and retention testing took place 24 h after extinction. In both f...

  10. The flavonoid apigenin delays forgetting of passive avoidance conditioning in rats.

    Science.gov (United States)

    Popović, Miroljub; Caballero-Bleda, María; Benavente-García, Obdulio; Castillo, Julián

    2014-05-01

    The present experiments were performed to study the effect of the flavonoid apigenin (20 mg/kg intraperitoneally (i.p.), 1 h before acquisition), on 24 h retention performance and forgetting of a step-through passive avoidance task, in young male Wistar rats. There were no differences between saline- and apigenin-treated groups in the 24 h retention trial. Furthermore, apigenin did not prevent the amnesia induced by scopolamine (1mg/kg, i.p., 30 min before the acquisition). The saline- and apigenin-treated rats that did not step through into the dark compartment during the cut-off time (540 s) were retested weekly for up to eight weeks. In the saline treated group, the first significant decline in passive avoidance response was observed at four weeks, and complete memory loss was found five weeks after the acquisition of the passive avoidance task. At the end of the experimental period, 60% of the animals treated with apigenin still did not step through. These data suggest that 1) apigenin delays the long-term forgetting but did not modulate the 24 h retention of fear memory and 2) the obtained beneficial effect of apigenin on the passive avoidance conditioning is mediated by mechanisms that do not implicate its action on the muscarinic cholinergic system.

  11. Retailer’s replenishment policies under conditions of permissible delay in payments

    Directory of Open Access Journals (Sweden)

    Huang Yung-Fu

    2004-01-01

    Full Text Available Goyal (1985 is frequently cited when the inventory systems under conditions of permissible delay in payments are discussed. Goyal implicitly assumed that: 1. The unit selling price and the unit purchasing price are equal; 2. At the end of the credit period, the account is settled. The retailer starts paying for higher interest charges on the items in stock and returns money of the remaining balance immediately when the items are sold. But these assumptions are debatable in real-life situations. The main purpose of this paper is to modify Goyal’s model to allow the unit selling price and the unit purchasing price not necessarily be equal to reflect the real-life situations. Furthermore, this paper will adopt different payment rule. We assume that the retailer uses sales revenue during the permissible credit period to make payment to the supplier at the end of the credit period. If it is not enough to pay off the purchasing cost of all items, the retailer will pay off the remaining balance by taking loan from the bank. So, the retailer starts paying for the interest charges on the amount of loan from the bank after the account is settled. Then the retailer will return money to the bank at the end of the inventory cycle. Under these conditions, we model the retailer’s inventory system as a cost minimization problem to determine the retailer’s optimal cycle time and optimal order quantity. Four cases are developed to efficiently determine the optimal cycle time and the optimal order quantity. Numerical examples are given to illustrate these cases. Comparing with Goyal’s model, we also find that the optimal cycle times in this paper are not longer than those of Goyal’s model.

  12. Startle eye-blink modulation by facial self-resemblance and current mood.

    Science.gov (United States)

    Finke, Johannes B; Larra, Mauro F; Schilling, Thomas M; Lass-Hennemann, Johanna; Blumenthal, Terry D; Schächinger, Hartmut

    2015-06-01

    Although salient stimuli are known to modulate startle eye-blink responses, and one's own face is considered of particular salience, effects of facial self-resemblance on startle responsiveness have not been systematically investigated. For the present study, pictures from the FACES database (rated as neutral) were digitally morphed to resemble the participants' (N=37) faces to varying degrees (25-50-75%). Perceptually matched geometrical shapes served as a control condition. At SOAs of either 300ms or 3000ms after picture onset, startle responses were elicited by white noise (50ms, 105dB), and recorded at the orbicularis oculi via EMG. Prior to the experiment, self-reported mood was assessed by means of the PANAS. Relative to non-face stimuli, the presentation of faces reduced startle magnitude at short, but not long, lead intervals. Furthermore, for probes presented at a SOA of 300ms, a linear decrease in startle magnitude with higher levels of self-resemblance was observed, presumably reflecting higher salience of the self-face. The startle modulating effect of self-resembling faces during longer lead intervals was moderated by the participants' current mood: negative affect predicted stronger patterns of attenuation, which might be interpreted as an increase in self-focus resulting from more negative mood.

  13. Hippocampal lesions impair performance on a conditional delayed matching and non-matching to position task in the rat.

    Science.gov (United States)

    Sloan, Hazel L; Döbrössy, Màtè; Dunnett, Stephen B

    2006-08-10

    The hippocampus is thought to be involved in a range of cognitive processes, from the ability to acquire new memories, to the ability to learn about spatial relationships. Humans and monkeys with damage to the hippocampus are typically impaired on delayed matching to sample tasks, of which the operant delayed matching to position task (DMTP) is a rat analogue. The reported effects of hippocampal damage on DMTP vary, ranging from delay-dependent deficits to no deficit whatsoever. The present study investigates a novel memory task; the conditional delayed matching/non-matching to position task (CDM/NMTP) in the Skinner box. CDM/NMTP uses the presence of specific stimulus cues to signify whether a particular trial is matching or non-matching in nature. Thus, it incorporates both the task contingencies within one session, and supplements the requirement for remembering the side of the lever in the sample phase with attending to the stimulus and remembering the conditional discrimination for the rule. Rats were trained preoperatively and the effects of bilateral excitotoxic lesions of the hippocampus were examined on postoperative retention of the task. Rats with lesions of the hippocampus incurred a significant impairment on the task that was manifest at all delays intervals. Despite a bias towards matching during training, trials of either type were performed with equivalent accuracy and neither rule was affected differentially by the lesion. This task may prove useful in determining the cognitive roles of a range of brain areas.

  14. Delay-Induced Attenuation of Latent Inhibition with a Conditioned Emotional Response Depends on CS-US Strength

    Science.gov (United States)

    De la Casa, Luis G.; Diaz, Estrella; Lubow, R.E.

    2005-01-01

    Latent Inhibition (LI) attenuation when a long delay is introduced between acquisition and test phases has been repeatedly observed using aversive conditioning procedures (e.g., Aguado, Symonds, & Hall, 1994). This effect has been used as evidence to support those theories that consider LI to be the result of a retrieval failure. We designed three…

  15. Novel conditions on exponential stability of a class of delayed neural networks with state-dependent switching.

    Science.gov (United States)

    Zhang, Guodong; Shen, Yi

    2015-11-01

    This paper is concerned with the global exponential stability on a class of delayed neural networks with state-dependent switching. Under the novel conditions, some sufficient criteria ensuring exponential stability of the proposed system are obtained. In particular, the obtained conditions complement and improve earlier publications on conventional neural networks with continuous or discontinuous right-hand side. Numerical simulations are also presented to illustrate the effectiveness of the obtained results.

  16. Preliminary development of flaw evaluation procedures for delayed hydride cracking initiation under hydride non-ratcheting conditions

    Energy Technology Data Exchange (ETDEWEB)

    Xu, S.; Cui, J.; Kawa, D.; Shek, G.K.; Scarth, D.A. [Kinectrics Inc., Toronto, Ontario (Canada)

    2006-07-01

    The flaw evaluation procedure for Delayed Hydride Cracking (DHC) initiation currently provided in the CSA Standard N285.8 was developed for hydride ratcheting conditions, in which flaw-tip hydrides do not completely dissolve at peak temperature. Test results have shown that hydrided regions formed under non-ratcheting conditions, in which flaw-tip hydrides completely dissolve at peak temperature, have significantly higher resistance to cracking than those formed under ratcheting conditions. This paper presents some preliminary work on the development of a procedure for the evaluation of DHC initiation for flaws under hydride non-ratcheting conditions. (author)

  17. Multiple memory systems, development and conditioning.

    Science.gov (United States)

    Stanton, M E

    2000-06-01

    A century of behavioral and neurobiological research suggests that Pavlovian conditioning involves three component memory systems: sensorimotor, affective and cognitive. In classical eyeblink conditioning, there is evidence that these three memory systems involve, respectively, the cerebellum, amygdala and hippocampus. This article reviews developmental research on eyeblink conditioning in rodents that is beginning to characterize ontogenetic dissociations and interactions among these memory systems. This research shows that the functional development of the affective system (conditioned fear response) precedes that of the sensorimotor system (conditioned eyeblink reflex). Modulation of these two systems by cognitive processes also seems to emerge at different points in ontogeny. Implications for cognitive development and research on multiple memory systems are discussed.

  18. Amygdala kindling disrupts trace and delay fear conditioning with parallel changes in Fos protein expression throughout the limbic brain.

    Science.gov (United States)

    Botterill, J J; Fournier, N M; Guskjolen, A J; Lussier, A L; Marks, W N; Kalynchuk, L E

    2014-04-18

    Amygdala kindling is well known to increase unconditioned fear and anxiety. However, relatively little is known about whether this form of kindling causes functional changes within the neural circuitry that mediates fear learning and the retrieval of fear memories. To address this issue, we examined the effect of short- (i.e., 30 stimulations) and long-term (i.e., 99 stimulations) amygdala kindling in rats on trace and delay fear conditioning, which are aversive learning tasks that rely predominantly on the hippocampus and amygdala, respectively. After memory retrieval, we analyzed the pattern of neural activity with Fos, the protein product of the immediate early gene c-fos. We found that kindling had no effect on acquisition of the trace fear conditioning task but it did selectively impair retrieval of this fear memory. In contrast, kindling disrupted both acquisition and retrieval of fear memory in the delay fear conditioning task. We also found that kindling-induced impairments in memory retrieval were accompanied by decreased Fos expression in several subregions of the hippocampus, parahippocampus, and amygdala. Interestingly, decreased freezing in the trace conditioning task was significantly correlated with dampened Fos expression in hippocampal and parahippocampal regions whereas decreased freezing in the delay conditioning task was significantly correlated with dampened Fos expression in hippocampal, parahippocampal, and amygdaloid circuits. Overall, these results suggest that amygdala kindling promotes functional changes in brain regions involved in specific types of fear learning and memory. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

  19. Visual Localisation of Mobile Devices in an Indoor Environment under Network Delay Conditions

    CERN Document Server

    Fernández, Alberto Alonso; Alonso, Ignacio González; Hu, Huosheng; 10.5121/ijdps.2011.2201

    2011-01-01

    Current progresses in home automation and service robotic environment have highlighted the need to develop interoperability mechanisms that allow a standard communication between the two systems. During the development of the DHCompliant protocol, the problem of locating mobile devices in an indoor environment has been investigated. The communication of the device with the location service has been carried out to study the time delay that web services offer in front of the sockets. The importance of obtaining data from real-time location systems portends that a basic tool for interoperability, such as web services, can be ineffective in this scenario because of the delays added in the invocation of services. This paper is focused on introducing a web service to resolve a coordinates request without any significant delay in comparison with the sockets.

  20. M-matrix-based stability conditions for genetic regulatory networks with time-varying delays and noise perturbations.

    Science.gov (United States)

    Tian, Li-Ping; Shi, Zhong-Ke; Liu, Li-Zhi; Wu, Fang-Xiang

    2013-10-01

    Stability is essential for designing and controlling any dynamic systems. Recently, the stability of genetic regulatory networks has been widely studied by employing linear matrix inequality (LMI) approach, which results in checking the existence of feasible solutions to high-dimensional LMIs. In the previous study, the authors present several stability conditions for genetic regulatory networks with time-varying delays, based on M-matrix theory and using the non-smooth Lyapunov function, which results in determining whether a low-dimensional matrix is a non-singular M-matrix. However, the previous approach cannot be applied to analyse the stability of genetic regulatory networks with noise perturbations. Here, the authors design a smooth Lyapunov function quadratic in state variables and employ M-matrix theory to derive new stability conditions for genetic regulatory networks with time-varying delays. Theoretically, these conditions are less conservative than existing ones in some genetic regulatory networks. Then the results are extended to genetic regulatory networks with time-varying delays and noise perturbations. For genetic regulatory networks with n genes and n proteins, the derived conditions are to check if an n × n matrix is a non-singular M-matrix. To further present the new theories proposed in this study, three example regulatory networks are analysed.

  1. A BOLD signature of eyeblinks in the visual cortex.

    Science.gov (United States)

    Hupé, Jean-Michel; Bordier, Cécile; Dojat, Michel

    2012-05-15

    We are usually unaware of the brief but large illumination changes caused by blinks, presumably because of blink suppression mechanisms. In fMRI however, increase of the BOLD signal was reported in the visual cortex, e.g. during blocks of voluntary blinks (Bristow, Frith and Rees, 2005) or after spontaneous blinks recorded during the prolonged fixation of a static stimulus (Tse, Baumgartner and Greenlee, 2010). We tested whether such activation, possibly related to illumination changes, was also present during standard fMRI retinotopic and visual experiments and was large enough to contaminate the BOLD signal we are interested in. We monitored in a 3T scanner the eyeblinks of 14 subjects who observed three different types of visual stimuli, including periodic rotating wedges and contracting/expanding rings, event-related Mondrians and graphemes, while fixating. We performed event-related analyses on the set of detected spontaneous blinks. We observed large and widespread BOLD responses related to blinks in the visual cortex of every subject and whatever the visual stimulus. The magnitude of the modulation was comparable to visual stimulation. However, blink-related activations lay mostly in the anterior parts of retinotopic visual areas, coding the periphery of the visual field well beyond the extent of our stimuli. Blinks therefore represent an important source of BOLD variations in the visual cortex and a troublesome source of noise since any correlation, even weak, between the distribution of blinks and a tested protocol could trigger artifactual activities. However, the typical signature of blinks along the anterior calcarine and the parieto-occipital sulcus allows identifying, even in the absence of eyetracking, fMRI protocols possibly contaminated by a heterogeneous distribution of blinks.

  2. Affective Modulation of the Startle Eyeblink and Postauricular Reflexes in Autism Spectrum Disorder

    Science.gov (United States)

    Dichter, Gabriel S.; Benning, Stephen D.; Holtzclaw, Tia N.; Bodfish, James W.

    2010-01-01

    Eyeblink and postauricular reflexes to standardized affective images were examined in individuals without (n = 37) and with (n = 20) autism spectrum disorders (ASDs). Affective reflex modulation in control participants replicated previous findings. The ASD group, however, showed anomalous reflex modulation patterns, despite similar self-report…

  3. Undernutrition during the brain growth period of the rat significantly delays the development of processes mediating Pavlovian trace conditioning.

    Science.gov (United States)

    Rudy, J W; Castro, C A

    1990-05-01

    Pavlovian trace conditioning procedures allow one to assess the ability of animals to associate events that are temporally separated because the conditioned stimulus terminates prior to the occurrence of the unconditioned stimulus. We report that undernutrition during Postnatal Days 2-18 significantly delays the development of trace conditioning to a visual stimulus. Previously undernourished 20-day-old rats conditioned when no temporal interval separated the termination of the CS and US onset (0-s trace interval). However, it was not until the undernourished pups were 30 days old that they conditioned when the trace interval was 10 or 30 s. In contrast, control pups only 20 days old were able to condition when a 10-s trace interval separated the CS and US events, and 25-day-old control pups conditioned when the interval was either 10 or 30 s. These results suggest that undernutrition delays the development of processes that enable the rat to sustain a representation of a visual CS during the trace interval.

  4. Visual Localisation of Mobile Devices in an Indoor Environment Under Network Delay Conditions

    Directory of Open Access Journals (Sweden)

    Huosheng Hu

    2011-03-01

    Full Text Available Current progresses in home automation and service robotic environment have highlighted the need todevelop interoperability mechanisms that allow a standard communication between the two systems.During the development of the DHCompliant protocol, the problem of locating mobile devices in anindoor environment has been investigated. The communication of the device with the location service hasbeen carried out to study the time delay that web services offer in front of the sockets. The importance ofobtaining data from real-time location systems portends that a basic tool for interoperability, such as webservices, can be ineffective in this scenario because of the delays added in the invocation of services. Thispaper is focused on introducing a web service to resolve a coordinates request without any significantdelay in comparison with the sockets.

  5. Bounded Mean-Delay Throughput and Non-Starvation Conditions in Aloha Network

    CERN Document Server

    Liew, Soung Chang; Chen, Da Rui

    2008-01-01

    This paper considers the requirements to ensure bounded mean queuing delay and non-starvation in a slotted Aloha network operating the exponential backoff protocol. It is well-known that the maximum possible throughput of a slotted Aloha system with a large number of nodes is 1/e = 0.3679. Indeed, a saturation throughput of 1/e can be achieved with an exponential backoff factor of r = e/(e-1)=1.5820. The binary backoff factor of r = 2 is assumed in the majority of prior work, and in many practical multiple-access networks such as the Ethernet and WiFi. For slotted Aloha, the saturation throughput 0.3466 for r = 2 is reasonably close to the maximum of 1/e, and one could hardly raise objection to adopting r = 2 in the system. However, this paper shows that if mean queuing delay is to be bounded, then the sustainable throughput when r = 2 is only 0.2158, a drastic 41% drop from 1/e . Fortunately, the optimal setting of r = 1.3757 under the bounded mean-delay requirement allows us to achieve sustainable throughpu...

  6. Eyeblink rate watching classical Hollywood and post-classical MTV editing styles, in media and non-media professionals.

    Science.gov (United States)

    Andreu-Sánchez, Celia; Martín-Pascual, Miguel Ángel; Gruart, Agnès; Delgado-García, José María

    2017-02-21

    While movie edition creates a discontinuity in audio-visual works for narrative and economy-of-storytelling reasons, eyeblink creates a discontinuity in visual perception for protective and cognitive reasons. We were interested in analyzing eyeblink rate linked to cinematographic edition styles. We created three video stimuli with different editing styles and analyzed spontaneous blink rate in participants (N = 40). We were also interested in looking for different perceptive patterns in blink rate related to media professionalization. For that, of our participants, half (n = 20) were media professionals, and the other half were not. According to our results, MTV editing style inhibits eyeblinks more than Hollywood style and one-shot style. More interestingly, we obtained differences in visual perception related to media professionalization: we found that media professionals inhibit eyeblink rate substantially compared with non-media professionals, in any style of audio-visual edition.

  7. Delayed Puberty

    DEFF Research Database (Denmark)

    Kolby, Nanna; Busch, Alexander Siegfried; Juul, Anders

    2017-01-01

    Delayed puberty can be a source of great concern and anxiety, although it usually is caused by a self-limiting variant of the normal physiological timing named constitutional delay of growth and puberty (CDGP). Delayed puberty can, however, also be the first presentation of a permanent condition ...... mineral density) and psychological (e.g., low self-esteem) and underline the importance of careful clinical assessment of the patients.......Delayed puberty can be a source of great concern and anxiety, although it usually is caused by a self-limiting variant of the normal physiological timing named constitutional delay of growth and puberty (CDGP). Delayed puberty can, however, also be the first presentation of a permanent condition...

  8. Classical conditioning for preserving the effects of short melatonin treatment in children with delayed sleep: a pilot study

    Science.gov (United States)

    van Maanen, Annette; Meijer, Anne Marie; Smits, Marcel G; Oort, Frans J

    2017-01-01

    Melatonin treatment is effective in treating sleep onset problems in children with delayed melatonin onset, but effects usually disappear when treatment is discontinued. In this pilot study, we investigated whether classical conditioning might help in preserving treatment effects of melatonin in children with sleep onset problems, with and without comorbid attention deficit hyperactivity disorder (ADHD) or autism. After a baseline week, 16 children (mean age: 9.92 years, 31% ADHD/autism) received melatonin treatment for 3 weeks and then gradually discontinued the treatment. Classical conditioning was applied by having children drink organic lemonade while taking melatonin and by using a dim red light lamp that was turned on when children went to bed. Results were compared with a group of 41 children (mean age: 9.43 years, 34% ADHD/autism) who received melatonin without classical conditioning. Melatonin treatment was effective in advancing dim light melatonin onset and reducing sleep onset problems, and positive effects were found on health and behavior problems. After stopping melatonin, sleep returned to baseline levels. We found that for children without comorbidity in the experimental group, sleep latency and sleep start delayed less in the stop week, which suggests an effect of classical conditioning. However, classical conditioning seems counterproductive in children with ADHD or autism. Further research is needed to establish these results and to examine other ways to preserve melatonin treatment effects, for example, by applying morning light.

  9. Informative conditions for the data set in an MIMO networked control system with delays, packet dropout and transmission scheduling

    Science.gov (United States)

    Zhang, Cong; Xiong, Zhihua; Ye, Hao

    2014-07-01

    In system identification, a data set needs to be informative to guarantee that the identification criterion has a unique global minimum asymptotically and the parameter estimation is consistent. In this paper, we study the informativity of the data set in a multiple-input and multiple-output (MIMO) networked control system (NCS), which contains possible network-induced delays, packet dropout, transmission scheduling, or a combination of these factors in network transmission. Moreover, to guarantee the data set of this MIMO NCS to be informative, a group of conditions for network transmission and controller's proportional term are developed. Finally, simulation studies are given to illustrate the result.

  10. An integrated supply chain model for deteriorating items considering delay in payments, imperfect quality and inspection errors under inflationary conditions

    DEFF Research Database (Denmark)

    Mahmoudinezhad, Mahvash; Mirzazadeh, Abolfazl; Ghoreishi, Maryam

    2016-01-01

    In this article, an integrated production–distribution model is presented for a manufacturer and retailer supply chain under inflationary conditions, permissible delay in payments, deterioration, imperfect production process and inspection errors. We assume that the first-stage inspection...... is conducted without inspection errors, and the screening process and demand proceed simultaneously. The main objective is to determine the optimal inspection time and the optimal number of cycle such that the present value of the total cost is minimized. Finally, a numerical example and sensitivity analyses...

  11. Effect of acid pre-conditioning and/or delayed light irradiation on enamel bond strength of three resin-modified glass ionomers

    Directory of Open Access Journals (Sweden)

    Maryam Khoroushi

    2013-01-01

    Conclusion: Within the limitations of the present study, the effect of acid pre-conditioning, delaying irradiation and both on enamel bond strength of RMGIs was material-dependent. Further investigations are recommended.

  12. Variability of ICA decomposition may impact EEG signals when used to remove eyeblink artifacts.

    Science.gov (United States)

    Pontifex, Matthew B; Gwizdala, Kathryn L; Parks, Andrew C; Billinger, Martin; Brunner, Clemens

    2017-03-01

    Despite the growing use of independent component analysis (ICA) algorithms for isolating and removing eyeblink-related activity from EEG data, we have limited understanding of how variability associated with ICA uncertainty may be influencing the reconstructed EEG signal after removing the eyeblink artifact components. To characterize the magnitude of this ICA uncertainty and to understand the extent to which it may influence findings within ERP and EEG investigations, ICA decompositions of EEG data from 32 college-aged young adults were repeated 30 times for three popular ICA algorithms. Following each decomposition, eyeblink components were identified and removed. The remaining components were back-projected, and the resulting clean EEG data were further used to analyze ERPs. Findings revealed that ICA uncertainty results in variation in P3 amplitude as well as variation across all EEG sampling points, but differs across ICA algorithms as a function of the spatial location of the EEG channel. This investigation highlights the potential of ICA uncertainty to introduce additional sources of variance when the data are back-projected without artifact components. Careful selection of ICA algorithms and parameters can reduce the extent to which ICA uncertainty may introduce an additional source of variance within ERP/EEG studies.

  13. The relationship between eye-winking tics, frequent eye-blinking and blepharospasm.

    Science.gov (United States)

    Elston, J S; Granje, F C; Lees, A J

    1989-04-01

    A family is reported in which three generations were affected with eye-winking tics and/or blepharospasm. The proband developed eye-winking tics in childhood and then developed excessive blinking progressing to blepharospasm by the age of 21 years. His mother presented with Meige's syndrome and spasmodic torticollis at the age of 59 years; his uncle had blinked excessively from his early forties. His eldest son developed an eye-winking tic with facial grimacing at the age of 8 years, and in another son, a self-limiting period of eye-blinking occurred at the age of 4 years. The recovery cycle of the blink reflex was abnormal in all three generations. Three other children with eye-winking tics have a parent or close relative with frequent eye-blinking or blepharospasm. Five patients with adult-onset blepharospasm or Meige's syndrome are also described who had excessive eye-blinking dating back to childhood. It is suggested that eye-winking tics, frequent blinking and blepharospasm may share common pathophysiological mechanisms; the clinical expression may be age-related.

  14. Excess production of phage lambda delayed early proteins under conditions supporting high Escherichia coli growth rates.

    Science.gov (United States)

    Gabig, M; Obuchowski, M; Wegrzyn, A; Szalewska-Pałasz, A; Thomas, M S; Wegrzyn, G

    1998-08-01

    Bacteriophage lambda is unable to lysogenize Escherichia coli hosts harbouring the rpoA341 mutation due to a drastic reduction in transcription from CII-activated lysogenic promoters (pE, pI and paQ). In addition, the level of early transcripts involved in the lytic pathway of lambda development is also decreased in this genetic background due to impaired N-dependent antitermination. Here, it is demonstrated that despite the reduced level of early lytic pL- and pR-derived transcripts, lytic growth of bacteriophage lambda is not affected in rich media. The level of the late lytic, pR-derived transcripts also remains unaffected by the rpoA341 mutation under these conditions. However, it was found that whilst there is no significant difference in the phage burst size in rpoA+ and rpoA341 hosts growing in rich media, phage lambda is not able to produce progeny in the rpoA341 mutant growing in minimal medium, in contrast to otherwise isogenic rpoA+ bacteria. Provision of an excess of the phage replication proteins O and P in trans or overproduction of the antitermination protein N restore the ability of phage lambda to produce progeny in the rpoA341 mutant under the latter conditions. These results suggest that in rich media phage lambda produces some early proteins in excess of that needed for its effective propagation and indicate that replication proteins may be limiting factors for phage lytic growth in poor media.

  15. Delayed effects of obese and overweight population conditions on all-cause adult mortality rate in the USA

    Directory of Open Access Journals (Sweden)

    Albert A Okunade

    2016-09-01

    Full Text Available Currently, there are few studies separating the linkage of pathological obese and overweight body mass indices (BMI to the all-cause mortality rate in adults. Consequently, this paper, using annual Behavioral Risk Factor Surveillance System (BRFSS data of the 50 US states and the District of Columbia (DC estimates empirical regression models linking the US adult population overweight and obesity rates separately to the all-cause mortality rate. The biochemistry of multi-period cumulative adiposity (saturated fatty acid from unexpended caloric intakes (net energy storage provides the natural theoretical foundation for tracing unhealthy BMI to all-cause mortality. Cross-sectional and panel data regression models are separately estimated for the delayed effects of obese and overweight BMIs on the all-cause mortality rate. Controlling for the independent effects of economic, socio-demographic and other factors on the all-cause mortality rate, our findings confirm that the estimated panel data models are more appropriate. The panel data regression results reveal that the obesity-mortality link strengthens significantly after multiple years in the condition. The faster mortality response to obesity detected here is conjectured to arise from the significantly more obese. Compared with past studies postulating a static (rather than delayed effects, the statistically significant lagged effects of adult population BMI pathology in this study are novel and insightful. And, as expected, these lagged effects are more severe in the obese than overweight population segment. Public health policy implications of this social science study findings agree with those of the clinical sciences literature advocating timely lifestyle modification interventions (e.g., smoking cessation to slow premature mortality linked to unhealthy BMIs.

  16. The delayed effects of DTG and MK-801 on latent inhibition in a conditioned taste-aversion paradigm.

    Science.gov (United States)

    Turgeon, S M; Auerbach, E A; Duncan-Smith, M K; George, J R; Graves, W W

    2000-07-01

    The delayed effects of phencyclidine (PCP) have been shown to disrupt latent inhibition (LI) in a conditioned taste-aversion paradigm. In an attempt to understand the mechanism of this disruption, the delayed effects of the selective sigma receptor agonist 1,3-Di(2-tolyl)guanidine (DTG) and the selective NMDA receptor antagonist MK-801 on latent inhibition were assessed in the same paradigm. Water-deprived male rats were allowed access to either water (nonpreexposed; NPE) or 5% sucrose (preexposed; PE) for 30 min on 2 consecutive days. On the third day, animals were allowed access to sucrose and subsequently injected with lithium chloride. On the forth day, animals were allowed access to both sucrose and water. LI was assessed by comparing the percent sucrose consumed in PE and NPE groups on the fourth day. DTG (1.0, 5.0, or 10.0 mg/kg), MK-801 (0.5, 1.0, or 2.0 mg/kg), or vehicle was administered IP 20 h before preexposure (days 1 and 2) and conditioning (day 3). In vehicle-treated groups, PE animals consumed a significantly higher percent sucrose on the test day than NPE animals, indicating the presence of LI. DTG (10.0 mg/kg) and MK-801 (2.0 mg/kg) decreased the percent sucrose consumed by animals in the PE group to the level observed in the NPE group, indicating disrupted LI. However, this dose of MK-801 was found to produce a decrease in percent sucrose consumed in PE animals not treated with lithium chloride, indicating that the decrease observed in the LI paradigm could be due to MK-801-induced decrease in taste preference for sucrose rather than a disruption of LI. Lower doses of MK-801 that did not produce a decrease in taste preference for sucrose did not significantly disrupt LI. None of the doses of DTG tested altered taste preference for sucrose. These data suggest a role for sigma receptors in the previously observed PCP-induced disruption of LI. Published by Elsevier Science Inc., 2000

  17. Improved Conditions for Global Asymptotic Stability of Cohen-Grossberg Neural Networks with Time-Varying Delays

    Institute of Scientific and Technical Information of China (English)

    CHEN Jun; CUI Bao-Tong; GAO Ming

    2008-01-01

    The global asymptotic stability of delayed Cohen-Grossberg neural networks with impulses is investigated. Based on the new suitable Lyapunov functions and the Jacobsthal inequality, a set of novel sufficient criteria are derived for the global asymptotic stability of Cohen-Grossberg neural networks with time-varying delays and impulses.An illustrative example with its numerical simulations is given to demonstrate the effectiveness of the obtained results.

  18. Regulated expression of a cytokinin biosynthesis gene IPT delays leaf senescence and improves yield under rainfed and irrigated conditions in canola (Brassica napus L..

    Directory of Open Access Journals (Sweden)

    Surya Kant

    Full Text Available Delay of leaf senescence through genetic modification can potentially improve crop yield, through maintenance of photosynthetically active leaves for a longer period. Plant growth hormones such as cytokinin regulate and delay leaf senescence. Here, the structural gene (IPT encoding the cytokinin biosynthetic enzyme isopentenyltransferase was fused to a functionally active fragment of the AtMYB32 promoter and was transformed into canola plants. Expression of the AtMYB32xs::IPT gene cassette delayed the leaf senescence in transgenic plants grown under controlled environment conditions and field experiments conducted for a single season at two geographic locations. The transgenic canola plants retained higher chlorophyll levels for an extended period and produced significantly higher seed yield with similar growth and phenology compared to wild type and null control plants under rainfed and irrigated treatments. The yield increase in transgenic plants was in the range of 16% to 23% and 7% to 16% under rainfed and irrigated conditions, respectively, compared to control plants. Most of the seed quality parameters in transgenic plants were similar, and with elevated oleic acid content in all transgenic lines and higher oil content and lower glucosinolate content in one specific transgenic line as compared to control plants. The results suggest that by delaying leaf senescence using the AtMYB32xs::IPT technology, productivity in crop plants can be improved under water stress and well-watered conditions.

  19. Enhancement of delay eyelid conditioning by microcurrent electrical stimulation of the medial prefrontal cortex is triggered by the expression of Fos protein in guinea pigs.

    Science.gov (United States)

    Zheng, Ya-Juan; Dong, Yu-Chen; Zhu, Chao; Zhao, Mei-Sheng

    2016-03-01

    Eyelid conditioning, including delay eyelid conditioning and trace eyelid conditioning, has been used extensively to study neural structures and mechanisms of learning and memory as a form of associative learning. In the present study, microcurrent electrical stimulation was used to stimulate the medial prefrontal cortex (mPFC) to induce delay eyelid conditioning in guinea pigs. The acquisition rate and relative latency of the conditioned eyelid response (CR) and the startle eyelid response (SR) were analyzed. The mPFC sites in the guinea pigs were examined under a light microscope following Nissl staining. In addition, the expression of Fos protein in neurons was detected using immunohistochemistry and western blot analysis. The results indicated that the acquisition rates of CR and SR were increased significantly (Pguinea pigs (Pguinea pigs was triggered by the expression of Fos protein. The observations of the present study further expand the understanding of conditioned reflexes and may aid future investigations into the formation of eyelid conditioning and the mechanisms underlying the circuit in various conditions.

  20. Modulation of eyeblink and postauricular reflexes during the anticipation and viewing of food images.

    Science.gov (United States)

    Hebert, Karen R; Valle-Inclán, Fernando; Hackley, Steven A

    2015-04-01

    One of the goals of neuroscience research on the reward system is to fractionate its functions into meaningful subcomponents. To this end, the present study examined emotional modulation of the eyeblink and postauricular components of startle in 60 young adults during anticipation and viewing of food images. Appetitive and disgusting photos served as rewards and punishments in a guessing game. Reflexes evoked during anticipation were not influenced by valence, consistent with the prevailing view that startle modulation indexes hedonic impact (liking) rather than incentive salience (wanting). During the slide-viewing period, postauricular reflexes were larger for correct than incorrect feedback, whereas the reverse was true for blink reflexes. Probes were delivered in brief trains, but only the first response exhibited this pattern. The specificity of affective startle modification makes it a valuable tool for studying the reward system. Copyright © 2014 Society for Psychophysiological Research.

  1. Infrared reflectance as an alternative to EMG for measuring prepulse inhibition of startle eyeblink.

    Science.gov (United States)

    Lovelace, Christopher T; Elmore, Wade R; Filion, Diane L

    2006-09-01

    The "gold standard" measure of the human startle eyeblink response is the ocular electromyogram (EMG). However, EMG measurement is not always feasible, as with special populations or during functional neuroimaging. We evaluated an alternative, nonelectrical, noncontact measure that uses infrared (IR) light reflected from the eye. By simultaneously recording IR and EMG during an acoustic prepulse inhibition of startle paradigm, we were able to directly compare the two measures and evaluate the relative reliability and validity of the IR measure as an index of startle response modulation. Although fewer responses were detected using IR than EMG, both measures were equally sensitive to prepulse modulation of response amplitude, latency, and probability. We conclude that when the goal is simply to assess the effects of a prepulse on the startle response, IR reflectance is an adequate alternative to EMG.

  2. Tourette Syndrome: Complementary Insights from Measures of Cognitive Control, Eyeblink Rate, and Pupil Diameter

    Science.gov (United States)

    Tharp, Jordan A.; Wendelken, Carter; Mathews, Carol A.; Marco, Elysa J.; Schreier, Herbert; Bunge, Silvia A.

    2015-01-01

    Some individuals with Tourette syndrome (TS) have severe motoric and vocal tics that interfere with all aspects of their lives, while others have mild tics that pose few problems. We hypothesize that observed tic severity reflects a combination of factors, including the degree to which dopaminergic (DA) and/or noradrenergic (NE) neurotransmitter systems have been affected by the disorder, and the degree to which the child can exert cognitive control to suppress unwanted tics. To explore these hypotheses, we collected behavioral and eyetracking data from 26 patients with TS and 26 controls between ages 7 and 14, both at rest and while they performed a test of cognitive control. To our knowledge, this is the first study to use eyetracking measures in patients with TS. We measured spontaneous eyeblink rate as well as pupil diameter, which have been linked, respectively, to DA and NE levels in the central nervous system. Here, we report a number of key findings that held when we restricted analyses to unmedicated patients. First, patients’ accuracy on our test of cognitive control accounted for fully 50% of the variance in parentally reported tic severity. Second, patients exhibited elevated spontaneous eyeblink rates compared to controls, both during task performance and at rest, consistent with heightened DA transmission. Third, although neither task-evoked pupil dilation nor resting pupil diameter differed between TS patients and controls, pupil diameter was positively related to parentally reported anxiety levels in patients, suggesting heightened NE transmission in patients with comorbid anxiety. Thus, with the behavioral and eyetracking data gathered from a single task, we can gather objective data that are related both to tic severity and anxiety levels in pediatric patients with TS, and that likely reflect patients’ underlying neurochemical disturbances. PMID:26175694

  3. Effects of medial septal lesions on action-outcome associations in rats under conditions of delayed reinforcement.

    Science.gov (United States)

    Numan, Robert; Ouimette, Amy S; Holloway, Katherine A; Curry, Cristi E

    2004-12-01

    In operant tasks, control rats maintain high response rates under positive contingencies, when the probability of reinforcement is greater following a response (contingent reinforcement) than during the absence of that response. However, as contingencies approach zero, response rates decrease. In this experiment, under immediate contingent reinforcement, rats with medial septal lesions reduced their response rates, just like controls, when contingencies were shifted from positive toward zero. However, the septal rats were less sensitive to this contingency shift, compared with controls, when there was a 5-s delay between lever presses and contingent reinforcements. This lesion effect appeared to be due to a failure of voluntary response memory, which impaired sensitivity to operant contingencies when there was a delay between action and outcome.

  4. Pre-pulse inhibition of the acoustic startle eye-blink in the Göttingen minipig

    DEFF Research Database (Denmark)

    Arnfred, Sidse Marie; Lind, Nanna Marie; Hansen, Axel Kornerup;

    2004-01-01

    by a weak white noise pre-pulse (PP), the interval between the PP and the startle noise stimulus (SNS) determining the degree of inhibition. Aiming at developing a new animal model of schizophrenia, we have investigated the acoustic startle eye-blink and PPI in 10 Göttingen minipigs. The stimuli......Pre-pulse inhibition (PPI) of the startle response is a measure of sensorimotor gating which has been frequently shown to be deficient in schizophrenic patients. In humans it is typically measured as the attenuation of the startle eye-blink reflex EMG when a startle eliciting noise is preceded...... and the block design of the stimulation were similar to paradigms used in human research. Initially the startle habituation across trials and blocks, secondarily the PPI at PP to SNS intervals of 30, 60, 120, 220, 520, 1020 and 2020 ms was investigated. One pig out of ten did not have a startle response...

  5. Destruction of central noradrenergic neurones with DSP4 impairs the acquisition of temporal discrimination but does not affect memory for duration in a delayed conditional discrimination task.

    Science.gov (United States)

    al-Zahrani, S S; al-Ruwaitea, A S; Ho, M Y; Bradshaw, C M; Szabadi, E

    1997-03-01

    This experiment examined the effect of destroying central noradrenergic neurones using the selective neurotoxin N-(2-chloroethyl)-n-ethyl-2-bromobenzylamine (DSP4) on the acquisition of a temporal discrimination and on memory for duration, using a delayed conditional discrimination task. In phase I, rats that had received systemic treatment with DSP4 and vehicle-treated control rats were trained in a series of discrete trials to press lever A following a 2-s presentation of a light stimulus, and lever B following an 8-s presentation of the same stimulus. Following stimulus offset, a response on a panel placed midway between the two levers was required to initiate lever presentation; a single response on either lever resulted in withdrawal of both levers and, in the case of a "correct" response, reinforcer delivery. Both groups acquired accurate discrimination, achieving 90% correct choices within 50 sessions; the DSP4-treated group acquired accurate performance more slowly than the control group. In phase II, delays were interposed between stimulus offset and lever presentation in 50% of the trials. In the absence of a delay, discriminative accuracy was lower in the DSP4-treated group than in the control group. Accuracy declined as a function of post-stimulus delay in both groups; both groups showed a delay-dependent bias towards responding on lever A ("choose-short" bias). Neither of these effects differed significantly between the two groups. The concentrations of noradrenaline in the parietal cortex and hippocampus were reduced by 90% and 89% in the DSP4-treated group, compared to the levels in the control group, but the levels of dopamine, 5-hydroxytryptamine and 5-hydroxyindoleacetic acid did not differ significantly between the groups. The results confirm the deleterious effect of DSP4 on the acquisition of temporal discrimination, but do not provide evidence for a role of the noradrenergic innervation of the hippocampus and neocortex in temporal working

  6. Effects of operating conditions on compositional characteristics and reaction kinetics of liquid derived by delayed coking of nigerian petroleum residue

    Directory of Open Access Journals (Sweden)

    O. O. Bello

    2006-09-01

    Full Text Available The thermal upgrading of Nigerian petroleum residue was studied at relatively low pressure in a delayed coking reactor system. In this work, the intent was to investigate the effects of process variables such as reaction temperature (200(0C to 600(0C, reaction time (0 to 120min, additive concentration loading and additive-to-residue ratio on the amounts and quality of organic liquid product (OLP. The liquid products derived from the delayed coking process were characterized by means of instrumental analysis of gas-liquid chromatography. Results obtained from the analyses of the OLP revealed an upward trend of the conversion process and the selectivity of the aromatic compounds with additive-to-residue ratio (ARR and increase in temperature. This led to maximum yield of 37.2% achieved with ARR of 5 compared to 31% achieved with ordinary thermal conversion. The selectivity for aromatic hydrocarbons was maximum at 83.1wt% the selectivity towards aromatics and aliphatic hydrocarbons were highest for methanol-potassium hydroxide and methanol respectively. In all additive system cases, maximum OLP was produced at an optimum reaction temperature of 370(0C in the delayed coking reactor and at higher residence time. The gaseous product consisted of carbon monoxide and carbon dioxide and C1 - C6 hydrocarbons, which amounted to about 20 to 30 wt% of liquid distillate. The information obtained in this study show that the organic liquid products are amenable to characterization procedure and provided the basis for the identification of processes for upgrading Nigerian petroleum residue and such other starting materials such as bitumen or fossil fuel coal liquids.

  7. Prefrontocortical dopamine loss in rats delays long-term extinction of contextual conditioned fear, and reduces social interaction without affecting short-term social interaction memory.

    Science.gov (United States)

    Fernandez Espejo, Emilio

    2003-03-01

    Prefrontal dopamine loss delays extinction of cued fear conditioning responses, but its role in contextual fear conditioning has not been explored. Medial prefrontal lesions also enhance social interaction in rats, but the role of prefrontal dopamine loss on social interaction memory is not known. Besides, a role for subcortical accumbal dopamine on mnesic changes after prefrontal dopamine manipulation has been proposed but not explored. The objective was to study the involvement of dopaminergic neurotransmission in the medial prefrontal cortex (mPFC) and nucleus accumbens in two mnesic tasks: contextual fear conditioning and social interaction memory. For contextual fear conditioning, short- and long-term freezing responses after an electric shock were studied, as well as extinction retention. Regarding social interaction memory, the recognition of a juvenile, a very sensitive short-term memory test, was used. Dopamine loss was carried out by injection of 6-hydroxydopamine, and postmortem catecholamine levels were analyzed by high-performance liquid chromatography. Prefrontocortical dopamine loss (>76%) led to a reactive enhancement of accumbal dopamine content (ploss. In lesioned rats, long-term extinction of contextual fear conditioning was significantly delayed and extinction retention was impaired without changes in acquisition and short-term contextual fear conditioning and, on the other hand, acquisition and short-term social interaction memory were not affected, although time spent on social interaction was significantly reduced. Added dopamine loss in the nucleus accumbens (>76%) did not alter these behavioral changes. In summary, the results of the present study indicate that the dopaminergic network in the mPFC (but not in the nucleus accumbens) coordinates the normal long-term extinction of contextual fear conditioning responses without affecting their acquisition, and it is involved in time spent on social interaction, but not acquisition and short

  8. Conditional deletion of Dicer in vascular smooth muscle cells leads to the developmental delay and embryonic mortality

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Yaoqian [Department of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163 (United States); Center for Cancer Research, University of Tennessee Health Science Center, Memphis, TN 38163 (United States); Balazs, Louisa [Department of Pathology, University of Tennessee Health Science Center, Memphis, TN 38163 (United States); Tigyi, Gabor [Department of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163 (United States); Yue, Junming, E-mail: yue@uthsc.edu [Department of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163 (United States); Center for Cancer Research, University of Tennessee Health Science Center, Memphis, TN 38163 (United States)

    2011-05-13

    Highlights: {yields} Deletion of Dicer in vascular smooth muscle cells(VSMCs) leads to embryonic mortality. {yields} Loss of Dicer in VSMCs leads to developmental delay. {yields} Loss of Dicer in VSMCs leads to hemorrhage in various organs including brain, skin and liver. {yields} Loss of Dicer in VSMCs leads to vascular wall remodeling. {yields} Loss of Dicer in VSMCs dysregulates the expression of miRNA and VSMC marker genes. -- Abstract: Dicer is a RNAase III enzyme that cleaves double stranded RNA and generates small interfering RNA (siRNA) and microRNA (miRNA). The goal of this study is to examine the role of Dicer and miRNAs in vascular smooth muscle cells (VSMCs). We deleted Dicer in VSMCs of mice, which caused a developmental delay that manifested as early as embryonic day E12.5, leading to embryonic death between E14.5 and E15.5 due to extensive hemorrhage in the liver, brain, and skin. Dicer KO embryos showed dilated blood vessels and a disarray of vascular architecture between E14.5 and E15.5. VSMC proliferation was significantly inhibited in Dicer KOs. The expression of VSMC marker genes were significantly downregulated in Dicer cKO embryos. The vascular structure of the yolk sac and embryo in Dicer KOs was lost to an extent that no blood vessels could be identified after E15.5. Expression of most miRNAs examined was compromised in VSMCs of Dicer KO. Our results indicate that Dicer is required for vascular development and regulates vascular remodeling by modulating VSMC proliferation and differentiation.

  9. Classical conditioning for preserving the effects of short melatonin treatment in children with delayed sleep: a pilot study

    National Research Council Canada - National Science Library

    van Maanen A; Meijer AM; Smits MG; Oort FJ

    2017-01-01

    .... In this pilot study, we investigated whether classical conditioning might help in preserving treatment effects of melatonin in children with sleep onset problems, with and without comorbid attention...

  10. Time Course of the Rabbit's Conditioned Nictitating Membrane Movements during Acquisition, Extinction, and Reacquisition

    Science.gov (United States)

    Kehoe, E. James; Ludvig, Elliot A.; Sutton, Richard S.

    2014-01-01

    The present experiment tested whether or not the time course of a conditioned eyeblink response, particularly its duration, would expand and contract, as the magnitude of the conditioned response (CR) changed massively during acquisition, extinction, and reacquisition. The CR duration remained largely constant throughout the experiment, while CR…

  11. Startling Sweet Temptations: Hedonic Chocolate Deprivation Modulates Experience, Eating Behavior, and Eyeblink Startle

    Science.gov (United States)

    Blechert, Jens; Naumann, Eva; Schmitz, Julian; Herbert, Beate M.; Tuschen-Caffier, Brunna

    2014-01-01

    Many individuals restrict their food intake to prevent weight gain. This restriction has both homeostatic and hedonic effects but their relative contribution is currently unclear. To isolate hedonic effects of food restriction, we exposed regular chocolate eaters to one week of chocolate deprivation but otherwise regular eating. Before and after this hedonic deprivation, participants viewed images of chocolate and images of high-calorie but non-chocolate containing foods, while experiential, behavioral and eyeblink startle responses were measured. Compared to satiety, hedonic deprivation triggered increased chocolate wanting, liking, and chocolate consumption but also feelings of frustration and startle potentiation during the intertrial intervals. Deprivation was further characterized by startle inhibition during both chocolate and food images relative to the intertrial intervals. Individuals who responded with frustration to the manipulation and those who scored high on a questionnaire of impulsivity showed more relative startle inhibition. The results reveal the profound effects of hedonic deprivation on experiential, behavioral and attentional/appetitive response systems and underscore the role of individual differences and state variables for startle modulation. Implications for dieting research and practice as well as for eating and weight disorders are discussed. PMID:24416437

  12. Startling sweet temptations: hedonic chocolate deprivation modulates experience, eating behavior, and eyeblink startle.

    Science.gov (United States)

    Blechert, Jens; Naumann, Eva; Schmitz, Julian; Herbert, Beate M; Tuschen-Caffier, Brunna

    2014-01-01

    Many individuals restrict their food intake to prevent weight gain. This restriction has both homeostatic and hedonic effects but their relative contribution is currently unclear. To isolate hedonic effects of food restriction, we exposed regular chocolate eaters to one week of chocolate deprivation but otherwise regular eating. Before and after this hedonic deprivation, participants viewed images of chocolate and images of high-calorie but non-chocolate containing foods, while experiential, behavioral and eyeblink startle responses were measured. Compared to satiety, hedonic deprivation triggered increased chocolate wanting, liking, and chocolate consumption but also feelings of frustration and startle potentiation during the intertrial intervals. Deprivation was further characterized by startle inhibition during both chocolate and food images relative to the intertrial intervals. Individuals who responded with frustration to the manipulation and those who scored high on a questionnaire of impulsivity showed more relative startle inhibition. The results reveal the profound effects of hedonic deprivation on experiential, behavioral and attentional/appetitive response systems and underscore the role of individual differences and state variables for startle modulation. Implications for dieting research and practice as well as for eating and weight disorders are discussed.

  13. Chronic psychosocial stress causes delayed extinction and exacerbates reinstatement of ethanol-induced conditioned place preference in mice

    OpenAIRE

    Bahi, Amine; Dreyer, Jean-Luc

    2014-01-01

    Objective: Here, we examined the impact of chronic subordinate colony (CSC) exposure on EtOH-CPP extinction, as well as ethanol-induced reinstatement of CPP.Methods: Mice were conditioned with saline or 1.5 g/kg ethanol and were tested in the EtOH-CPP model. In the first experiment, the mice were subjected to 19 days of chronic stress, and EtOH-CPP extinction was assessed during seven daily trials without ethanol injection. In the second experiment and after the EtOH-CPP test, the mice were s...

  14. OsBBX14 delays heading date by repressing florigen gene expression under long and short-day conditions in rice.

    Science.gov (United States)

    Bai, Bo; Zhao, Jie; Li, Yaping; Zhang, Fang; Zhou, Jinjun; Chen, Fan; Xie, Xianzhi

    2016-06-01

    B-box (BBX) proteins are zinc finger proteins containing B-box domains, which have roles in Arabidopsis growth and development. However, little is known concerning rice BBXs. Herein, we identified a rice BBX protein, Oryza sativa BBX14 (OsBBX14). OsBBX14 is highly expressed in flag leaf blades. OsBBX14 expression shows a diurnal rhythm under photoperiodic conditions and subsequent continuous white light. OsBBX14 is located in the nucleus and has transcriptional activation potential. OsBBX14-overexpression (OsBBX14-OX) lines exhibited delayed heading date under long-day (LD) and short-day (SD) conditions, whereas RNAi lines of OsBBX14 lines had similar heading dates to the WT. The florigen genes, Hd3a and RFT1, were downregulated in the OsBBX14-OX lines under LD and SD conditions. Under LD conditions, Hd1 was expressed higher in the OsBBX14-OX lines than in the wild type (WT), and the rhythmic expression of circadian clock genes, OsLHY and OsPRR1, was changed in OsBBX14-OX lines. Thus, OsBBX14 acts as a floral repressor by promoting Hd1 expression under LD conditions, probably because of crosstalk with the circadian clock. Under SD conditions, Ehd1 expression was reduced in OsBBX14-OX lines, but Hd1 and circadian clock gene expressions were unaffected, indicating that OsBBX14 acts as a repressor of Ehd1. Our findings suggested that OsBBX14 regulates heading date differently under LD and SD conditions.

  15. Repeated exposure to conditioned fear stress increases anxiety and delays sleep recovery following exposure to an acute traumatic stressor

    Directory of Open Access Journals (Sweden)

    Benjamin N Greenwood

    2014-10-01

    Full Text Available Repeated stressor exposure can sensitize physiological responses to novel stressors and facilitate the development of stress-related psychiatric disorders including anxiety. Disruptions in diurnal rhythms of sleep-wake behavior accompany stress-related psychiatric disorders and could contribute to their development. Complex stressors that include fear-eliciting stimuli can be a component of repeated stress experienced by humans, but whether exposure to repeated fear can prime the development of anxiety and sleep disturbances is unknown. In the current study, adult male F344 rats were exposed to either control conditions or repeated contextual fear conditioning for 22 days followed by exposure to either no, mild (10, or severe (100 acute uncontrollable tail shock stress. Exposure to acute stress produced anxiety-like behavior as measured by a reduction in juvenile social exploration and exaggerated shock-elicited freezing in a novel context. Prior exposure to repeated fear enhanced anxiety-like behavior as measured by shock-elicited freezing, but did not alter social exploratory behavior. The potentiation of anxiety produced by prior repeated fear was temporary; exaggerated fear was present 1 day but not 4 days following acute stress. Interestingly, exposure to acute stress reduced REM and NREM sleep during the hours immediately following acute stress. This initial reduction in sleep was followed by robust REM rebound and diurnal rhythm flattening of sleep / wake behavior. Prior repeated fear extended the acute stress-induced REM and NREM sleep loss, impaired REM rebound, and prolonged the flattening of the diurnal rhythm of NREM sleep following acute stressor exposure. These data suggest that impaired recovery of sleep / wake behavior following acute stress could contribute to the mechanisms by which a history of prior repeated stress increases vulnerability to subsequent novel stressors and stress-related disorders.

  16. Purkinje cell activity during classical conditioning with different conditional stimuli explains central tenet of Rescorla–Wagner model [corrected].

    Science.gov (United States)

    Rasmussen, Anders; Zucca, Riccardo; Johansson, Fredrik; Jirenhed, Dan-Anders; Hesslow, Germund

    2015-11-10

    A central tenet of Rescorla and Wagner's model of associative learning is that the reinforcement value of a paired trial diminishes as the associative strength between the presented stimuli increases. Despite its fundamental importance to behavioral sciences, the neural mechanisms underlying the model have not been fully explored. Here, we present findings that, taken together, can explain why a stronger association leads to a reduced reinforcement value, within the context of eyeblink conditioning. Specifically, we show that learned pause responses in Purkinje cells, which trigger adaptively timed conditioned eyeblinks, suppress the unconditional stimulus (US) signal in a graded manner. Furthermore, by examining how Purkinje cells respond to two distinct conditional stimuli and to a compound stimulus, we provide evidence that could potentially help explain the somewhat counterintuitive overexpectation phenomenon, which was derived from the Rescorla-Wagner model.

  17. The Influences of Pre-testing Reviews and Delays on Differentialassociative Processing versus A Condition in which Students chose their Learning Strategy.

    Science.gov (United States)

    Hannon, Brenda

    2013-10-01

    Recent studies show that a new strategy called differential-associative processing is effective for learning related concepts. However our knowledge about differential-associative processing is still limited. Therefore the goals of the present study are to assess the duration of knowledge that is acquired from using differential-associative processing, to determine whether the efficacy of differential-associative processing changes with the addition of a 10-minute pre-testing review, and to compare differential-associate processing to two conditions in which students select their own learning strategy. The results revealed that differential-associative processing was a better strategy for learning related concepts than were either of the two comparison conditions. They also revealed that a 10-minute pre-testing review had a positive additive influence on differential-associative processing. Finally, although the knowledge acquired from using differential-associative processing declined with an increase in delay between learning and testing, this decline was equivalent to the decline observed in both comparison conditions.

  18. Delay-dependent Conditions for Absolute Stability of Lurie Control Systems with Time-varying Delay%具有时变时滞的Lurie系统绝对稳定性的时滞相关条件

    Institute of Scientific and Technical Information of China (English)

    何勇; 吴敏

    2005-01-01

    Some delay-dependent absolute stability criteria for Lurie control systems with timevarying delay are derived, in which some free-weighting matrices are used to express the relationships between the terms in the Leibniz-Newton formula. These criteria are based on linear matrix inequality(LMI) such that the upper bound of time-delay guaranteeing the absolute stability and the free-weighting matrices can be obtained through the solutions of the LMI. Moreover, the Lyapunov functional constructed by the solutions of these LMIs is adopted to guarantee the absolute stability of the systems. Finally, some examples axe provided to demonstrate the effectiveness of the proposed methods.

  19. Positive priming and intentional binding: eye-blink rate predicts reward information effects on the sense of agency.

    Science.gov (United States)

    Aarts, Henk; Bijleveld, Erik; Custers, Ruud; Dogge, Myrthel; Deelder, Merel; Schutter, Dennis; Haren, Neeltje E M van

    2012-01-01

    Human society is strongly rooted in people's experiences of agency; that is, the pervasive feeling that one engages in voluntary behavior and causes one's own actions and resulting outcomes. Rewards and positive affect play an important role in the control of voluntary action. However, the role of positive reward signals in the sense of agency is poorly understood. This study examined effects of reward-related information on the sense of agency by employing the intentional binding paradigm. This paradigm measures the extent to which actions and their effects subjectively shift together across time, reflecting a crucial component of people's sense of agency. Results showed that intentional binding is stronger when participants are primed with reward-related information via brief exposure to positive pictures. Interestingly, this positive priming effect was moderated by baseline eye-blink rates (an indirect marker of striatal dopaminergic functioning); reward-related information increased intentional binding mainly for participants displaying higher baseline eye-blink rates. These findings suggest a possible role for striatal dopamine activity in the process by which reward-related information shapes the way people see themselves as agents.

  20. Eyelid contour detection and tracking for startle research related eye-blink measurements from high-speed video records.

    Science.gov (United States)

    Bernard, Florian; Deuter, Christian Eric; Gemmar, Peter; Schachinger, Hartmut

    2013-10-01

    Using the positions of the eyelids is an effective and contact-free way for the measurement of startle induced eye-blinks, which plays an important role in human psychophysiological research. To the best of our knowledge, no methods for an efficient detection and tracking of the exact eyelid contours in image sequences captured at high-speed exist that are conveniently usable by psychophysiological researchers. In this publication a semi-automatic model-based eyelid contour detection and tracking algorithm for the analysis of high-speed video recordings from an eye tracker is presented. As a large number of images have been acquired prior to method development it was important that our technique is able to deal with images that are recorded without any special parametrisation of the eye tracker. The method entails pupil detection, specular reflection removal and makes use of dynamic model adaption. In a proof-of-concept study we could achieve a correct detection rate of 90.6%. With this approach, we provide a feasible method to accurately assess eye-blinks from high-speed video recordings.

  1. 针对准单边Lipschitz不确定非线性时滞系统的稳定性分析%Stability Analysis for Uncertain Nonlinear Time-delay Systems with Quasi-one-sided Lipschitz Condition

    Institute of Scientific and Technical Information of China (English)

    祝乔; 胡广大

    2009-01-01

    This paper deals with the robust stability of a class of uncertain nonlinear time-delay systems. A quasi-one-sided Lipschitz condition is introduced to estimate the in-fluenee of nonlinear vector function on the stability analy-sis. Delay-independent/delay-dependent stability criteria for-mulated in the form of linear matrix inequalities are pre-sented. Furthermore, these stability criteria are available even if the system parameter is unstable, because the unneces-sary positive quasi-one-sided Lipschitz constant matrix includes much useful information of the nonlinear part. Numerical ex-amplee show the advantage of the results obtained in this paper.

  2. Storage of a naturally acquired conditioned response is impaired in patients with cerebellar degeneration.

    Science.gov (United States)

    Thieme, Andreas; Thürling, Markus; Galuba, Julia; Burciu, Roxana G; Göricke, Sophia; Beck, Andreas; Aurich, Volker; Wondzinski, Elke; Siebler, Mario; Gerwig, Marcus; Bracha, Vlastislav; Timmann, Dagmar

    2013-07-01

    Previous findings suggested that the human cerebellum is involved in the acquisition but not the long-term storage of motor associations. The finding of preserved retention in cerebellar patients was fundamentally different from animal studies which show that both acquisition and retention depends on the integrity of the cerebellum. The present study investigated whether retention had been preserved because critical regions of the cerebellum were spared. Visual threat eye-blink responses, that is, the anticipatory closure of the eyes to visual threats, have previously been found to be naturally acquired conditioned responses. Because acquisition is known to take place in very early childhood, visual threat eye-blink responses can be used to test retention in patients with adult onset cerebellar disease. Visual threat eye-blink responses were tested in 19 adult patients with cerebellar degeneration, 27 adult patients with focal cerebellar lesions due to stroke, 24 age-matched control subjects, and 31 younger control subjects. High-resolution structural magnetic resonance images were acquired in patients to perform lesion-symptom mapping. Voxel-based morphometry was performed in patients with cerebellar degeneration, and voxel-based lesion-symptom mapping in patients with focal disease. Visual threat eye-blink responses were found to be significantly reduced in patients with cerebellar degeneration. Visual threat eye-blink responses were also reduced in patients with focal disease, but to a lesser extent. Visual threat eye-blink responses declined with age. In patients with cerebellar degeneration the degree of cerebellar atrophy was positively correlated with the reduction of conditioned responses. Voxel-based morphometry showed that two main regions within the superior and inferior parts of the posterior cerebellar cortex contributed to expression of visual threat eye-blink responses bilaterally. Involvement of the more inferior parts of the posterior lobe was

  3. Delayed fission

    Energy Technology Data Exchange (ETDEWEB)

    Hatsukawa, Yuichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-07-01

    Delayed fission is a nuclear decay process that couples {beta} decay and fission. In the delayed fission process, a parent nucleus undergoes {beta} decay and thereby populates excited states in the daughter. If these states are of energies comparable to or greater than the fission barrier of the daughter, then fission may compete with other decay modes of the excited states in the daughter. In this paper, mechanism and some experiments of the delayed fission will be discussed. (author)

  4. On the Separability of Ill-Conditioned Convolutive Mixtures of Sources with Small Time Delay%微延迟病态卷积混叠盲源分离的可分性研究

    Institute of Scientific and Technical Information of China (English)

    刘海林; 谢胜利; 章晋龙

    2003-01-01

    The paper researches separability of blind sources of convolutive mixtures on the assumption that the num-ber of sensors is less than that of sources. When time delay is small, the necessary condition of separability of the ill-conditioned convolutive mixtures is given through transforming blind sources of convolutive mixtures into that of lin-ear mixtures.

  5. Delay-independent stabilization for teleoperation with time varying delay

    OpenAIRE

    Fujita, Hiroyuki; Namerikawa, Toru

    2009-01-01

    This paper deals with the stability for nonlinear teleoperation with time varying communication delays. The proposed method is passivity-based controllers with time varying gains which depend on the rate of change of time varying delay. In our proposed method, stability condition is independent of the magnitude of the communication delay and the damping of the system. The delay-independent stability is shown via Lyapunov stability methods. Several experimental results show the effectiveness o...

  6. Conditional loss of ErbB3 delays mammary gland hyperplasia induced by mutant PIK3CA without affecting mammary tumor latency, gene expression, or signaling.

    Science.gov (United States)

    Young, Christian D; Pfefferle, Adam D; Owens, Philip; Kuba, María G; Rexer, Brent N; Balko, Justin M; Sánchez, Violeta; Cheng, Hailing; Perou, Charles M; Zhao, Jean J; Cook, Rebecca S; Arteaga, Carlos L

    2013-07-01

    Mutations in PIK3CA, the gene encoding the p110α catalytic subunit of phosphoinositide 3-kinase (PI3K), have been shown to transform mammary epithelial cells (MEC). Studies suggest this transforming activity requires binding of mutant p110α via p85 to phosphorylated YXXM motifs in activated receptor tyrosine kinases (RTK) or adaptors. Using transgenic mice, we examined if ErbB3, a potent activator of PI3K, is required for mutant PIK3CA-mediated transformation of MECs. Conditional loss of ErbB3 in mammary epithelium resulted in a delay of PIK3CA(H1047R)-dependent mammary gland hyperplasia, but tumor latency, gene expression, and PI3K signaling were unaffected. In ErbB3-deficient tumors, mutant PI3K remained associated with several tyrosyl phosphoproteins, potentially explaining the dispensability of ErbB3 for tumorigenicity and PI3K activity. Similarly, inhibition of ErbB RTKs with lapatinib did not affect PI3K signaling in PIK3CA(H1047R)-expressing tumors. However, the p110α-specific inhibitor BYL719 in combination with lapatinib impaired mammary tumor growth and PI3K signaling more potently than BYL719 alone. Furthermore, coinhibition of p110α and ErbB3 potently suppressed proliferation and PI3K signaling in human breast cancer cells harboring PIK3CA(H1047R). These data suggest that PIK3CA(H1047R)-driven tumor growth and PI3K signaling can occur independently of ErbB RTKs. However, simultaneous blockade of p110α and ErbB RTKs results in superior inhibition of PI3K and mammary tumor growth, suggesting a rational therapeutic combination against breast cancers harboring PIK3CA activating mutations.

  7. 展宽段排队溢出状态下区段延误模型研究%Study on Section Delay Model under Widening Zone Queue Overflow Condition

    Institute of Scientific and Technical Information of China (English)

    2016-01-01

    为研究过饱和信号交叉口排队溢出状态下单周期通过展宽段车辆的区段延误模型,首先介绍了3大经典延误模型,提出了3大延误模型均未考虑展宽段长度和饱和流率的波动问题.其次,以展宽段为研究对象,在经典延误模型理论的基础上,推导出了展宽段区段延误模型.最后,从公式推导计算和VISSIM仿真两个方面对优化模型和定数理论延误模型进行了对比.结果表明:该模型能够有效地反映展宽段溢出状态下产生的区段延误,可为展宽段的科学设计提供理论基础.%In order to study the section delay model for vehicles passing widening zone in single cycle at oversaturated signalized intersection under queue overflow condition, first, we introduced 3 classical delay models, and put forward none of them considered the widening zone length and the fluctuation of saturation flow rate. Second, taking the widening zone as the research object, we derived the widening zone delay model on the basis of the classical delay model theory. Finally, we compared the optimization model and the fixed number theory based delay model by formula deriving/calculating and VISSIM simulation. The result shows that the proposed model can effectively reflect the section delay in widening zone under queue overflow condition, it can provide a theoretical basis for scientific design of widening zone.

  8. Disruption of bradycardia associated with discriminative conditioning in combat veterans with PTSD

    Directory of Open Access Journals (Sweden)

    Jay P Ginsberg

    2008-06-01

    Full Text Available Jay P Ginsberg1,2, Edwin Ayers3, Louisa Burriss1, Donald A Powell1,41Shirley L. Buchanan Neuroscience Laboratory, Dorn VA Medical Center, Columbia, SC, USA; 2Department of Pharmacology, Physiology, and Neuroscience, School of Medicine, 4Department of Psychology, University of South Carolina, Columbia, SC, USA; 3Department of Psychology, South Carolina State University, Orangeburg, SC, USAAbstract: The effects of combat-related posttraumatic stress disorder (PTSD on heart rate (HR responding associated with a discriminative delay eyeblink (EB conditioning paradigm are reported. Combat PTSD+, Combat PTSD−, and Noncombat PTSD− veterans were assessed with psychometric self-report measures, and baseline heart rate variability (HRV was measured before receiving a 72-trial session of discriminative EB classical conditioning. Two types (red or green light of conditioned stimuli (CS were used: one (CS+ predicted a tone, followed immediately by an aversive stimulus (corneal airpuff; the other (CS− predicted a tone alone, not followed by the airpuff. The light signal was presented for 5 seconds, during which HR was measured. On all psychometric measures, the PTSD+ subgroup was significantly different from the PTSD− subgroups (Combat + Noncombat, and the PTSD− subgroups did not significantly differ from each other. A linear deceleration in HR to CS+ and CS− signals was found in the combined PTSD− subgroup and on CS− trials in the PTSD+ subgroup, but was not present on CS+ trials in the PTSD+ subgroup. Results are interpreted with respect to a behavioral stages model of conditioned bradycardia and in terms of neural substrates which are both critical to HR conditioning and known to be abnormal in PTSD.Keywords: bradycardia, PTSD, combat veterans, classical conditioning

  9. Neuroscience and Learning: Lessons from Studying the Involvement of a Region of Cerebellar Cortex in Eyeblink Classical Conditioning

    Science.gov (United States)

    Villarreal, Ronald P.; Steinmetz, Joseph E.

    2005-01-01

    How the nervous system encodes learning and memory processes has interested researchers for 100 years. Over this span of time, a number of basic neuroscience methods has been developed to explore the relationship between learning and the brain, including brain lesion, stimulation, pharmacology, anatomy, imaging, and recording techniques. In this…

  10. Acute Exposure to Stress Improves Performance in Trace Eyeblink Conditioning and Spatial Learning Tasks in Healthy Men

    Science.gov (United States)

    Duncko, Roman; Cornwell, Brian; Cui, Lihong; Merikangas, Kathleen R.; Grillon, Christian

    2007-01-01

    The present study investigated the effects of acute stress exposure on learning performance in humans using analogs of two paradigms frequently used in animals. Healthy male participants were exposed to the cold pressor test (CPT) procedure, i.e., insertion of the dominant hand into ice water for 60 sec. Following the CPT or the control procedure,…

  11. Delayed childbearing.

    Science.gov (United States)

    Francis, H H

    1985-06-01

    In many Western nations, including England and Wales, Sweden, and the US, there is a current trend towards delayed childbearing because of women's pursuit of a career, later marriage, a longer interval between marriage and the 1st birth, and the increasing number of divorcees having children in a 2nd marriage. Wives of men in social classes I and II in England and Wales are, on average, having their 1st child at 27.9 years, 1.6 years later than in 1973, and in social classes IV and V, 1.0 years later than in 1973, at a mean age of 23.7 years. Consequently, the total period fertility rate for British women aged 30-34 years, 35-39 years, and 40 and over increased by 4%, 2%, and 4%, respectively, between 1982-83, in contrast to reductions of 2% and 3%, respectively, in the 15-19 year and 20-24 year age groups, with the 25-29-year-olds remaining static. The average maternal mortality for all parties in England and Wales during 1976-78 was 106/million for adolescents, 70.4/million for 20-24 year-olds, and 1162/million for those aged 40 years and older. The specific obstetric and allied conditions which increase with age are the hypertensive diseases of pregnancy, hemorrhage, pulmonary embolism, abortion, cardiac disease, caesarean section, ruptured uterus, and amniotic fluid embolism. The Swedish Medical Birth Registry of all live births and perinatal deaths since 1973 has shown that the risk of late fetal death is significantly greater in women aged 30-39 years than in those of the same parity and gravidity aged 20-24 years. The risk of giving birth to low birth weight babies preterm and at term and of premature labor are similarly increased. The early neonatal death rate also was increased for primigravidas and nulliparas in the 30-39 year age group but not in parous women. This is, in part, due to the rise in incidence of fetal abnormalities with advancing maternal age because of chromosomal and nonchromosomal anomalies. These also appear to be the cause of the

  12. Small delay approximation of stochastic delay differential equations

    Science.gov (United States)

    Guillouzic, Steve; L'heureux, Ivan; Longtin, André

    1999-04-01

    Delay differential equations evolve in an infinite-dimensional phase space. In this paper, we consider the effect of external fluctuations (noise) on delay differential equations involving one variable, thus leading to univariate stochastic delay differential equations (SDDE's). For small delays, a univariate nondelayed stochastic differential equation approximating such a SDDE is presented. Another approximation, complementary to the first, is also obtained using an average of the SDDE's drift term over the delayed dynamical variable, which defines a conditional average drift. This second approximation is characterized by the fact that the diffusion term is identical to that of the original SDDE. For small delays, our approach yields a steady-state probability density and a conditional average drift which are in close agreement with numerical simulations of the original SDDE. We illustrate this scheme with the delayed linear Langevin equation and a stochastic version of the delayed logistic equation. The technique can be used with any type of noise, and is easily generalized to multiple delays.

  13. conditions

    Directory of Open Access Journals (Sweden)

    M. Venkatesulu

    1996-01-01

    Full Text Available Solutions of initial value problems associated with a pair of ordinary differential systems (L1,L2 defined on two adjacent intervals I1 and I2 and satisfying certain interface-spatial conditions at the common end (interface point are studied.

  14. Delay-Dependent Observers for Uncertain Nonlinear Time-Delay Systems

    Directory of Open Access Journals (Sweden)

    Dongmei Yan

    2013-05-01

    Full Text Available This paper is concerned with the observer design problem for a class of discrete-time uncertain nonlinear systems with time-varying delay. The nonlinearities are assumed to satisfy global Lipschitz conditions which appear in both the state and measurement equations. The uncertainties are assumed to be time-varying but norm-bounded. Two Luenberger-like observers are proposed. One is delay observer and the other is delay-free observer. The delay observer which has an internal time delay is applicable when the time delay is known. The delay-free observer which does not use delayed information is especially applicable when the time delay is not known explicitly. Delay-dependent conditions for the existences of these two observers are derived based on Lyapunpv functional approach. Based on these conditions, the observer gains are obtained using the cone complementarity linearization algorithm. Finally, a numerical example is given to illustrate the effectiveness of the proposed method.

  15. Embodying approach motivation: body posture influences startle eyeblink and event-related potential responses to appetitive stimuli.

    Science.gov (United States)

    Price, Tom F; Dieckman, Laurtiz W; Harmon-Jones, Eddie

    2012-07-01

    Past research suggested that the motivational significance of images influences reflexive and electrocortical responses to those images (Briggs and Martin, 2009; Gard et al., 2007; Schupp et al., 2004), with erotica often exerting the largest effects for appetitive pictures (Grillon and Baas, 2003; Weinberg and Hajcak, 2010). This research paradigm, however, compares responses to different types of images (e.g., erotica vs. exciting sports scenes). This past motivational interpretation, therefore, would be further supported by experiments wherein appetitive picture content is held constant and motivational states are manipulated with a different method. In the present experiment, we tested the hypothesis that changes in physical postures associated with approach motivation influences reflexive and electrocortical responses to appetitive stimuli. Past research has suggested that bodily manipulations (e.g., facial expressions) play a role in emotion- and motivation-related physiology (Ekman and Davidson, 1993; Levenson et al., 1990). Extending these results, leaning forward (associated with a heightened urge to approach stimuli) relative to reclining (associated with less of an urge to approach stimuli) caused participants to have smaller startle eyeblink responses during appetitive, but not neutral, picture viewing. Leaning relative to reclining also caused participants to have larger LPPs to appetitive but not neutral pictures, and influenced ERPs as early as 100ms into stimulus viewing. This evidence suggests that body postures associated with approach motivation causally influence basic reflexive and electrocortical reactions to appetitive emotive stimuli. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Sex differences in learning processes of classical and operant conditioning.

    Science.gov (United States)

    Dalla, Christina; Shors, Tracey J

    2009-05-25

    Males and females learn and remember differently at different times in their lives. These differences occur in most species, from invertebrates to humans. We review here sex differences as they occur in laboratory rodent species. We focus on classical and operant conditioning paradigms, including classical eyeblink conditioning, fear-conditioning, active avoidance and conditioned taste aversion. Sex differences have been reported during acquisition, retention and extinction in most of these paradigms. In general, females perform better than males in the classical eyeblink conditioning, in fear-potentiated startle and in most operant conditioning tasks, such as the active avoidance test. However, in the classical fear-conditioning paradigm, in certain lever-pressing paradigms and in the conditioned taste aversion, males outperform females or are more resistant to extinction. Most sex differences in conditioning are dependent on organizational effects of gonadal hormones during early development of the brain, in addition to modulation by activational effects during puberty and adulthood. Critically, sex differences in performance account for some of the reported effects on learning and these are discussed throughout the review. Because so many mental disorders are more prevalent in one sex than the other, it is important to consider sex differences in learning when applying animal models of learning for these disorders. Finally, we discuss how sex differences in learning continue to alter the brain throughout the lifespan. Thus, sex differences in learning are not only mediated by sex differences in the brain, but also contribute to them.

  17. Sensory prediction or motor control? Application of marr-albus type models of cerebellar function to classical conditioning.

    Science.gov (United States)

    Lepora, Nathan F; Porrill, John; Yeo, Christopher H; Dean, Paul

    2010-01-01

    Marr-Albus adaptive filter models of the cerebellum have been applied successfully to a range of sensory and motor control problems. Here we analyze their properties when applied to classical conditioning of the nictitating membrane response in rabbits. We consider a system-level model of eyeblink conditioning based on the anatomy of the eyeblink circuitry, comprising an adaptive filter model of the cerebellum, a comparator model of the inferior olive and a linear dynamic model of the nictitating membrane plant. To our knowledge, this is the first model that explicitly includes all these principal components, in particular the motor plant that is vital for shaping and timing the behavioral response. Model assumptions and parameters were systematically investigated to disambiguate basic computational capacities of the model from features requiring tuning of properties and parameter values. Without such tuning, the model robustly reproduced a range of behaviors related to sensory prediction, by displaying appropriate trial-level associative learning effects for both single and multiple stimuli, including blocking and conditioned inhibition. In contrast, successful reproduction of the real-time motor behavior depended on appropriate specification of the plant, cerebellum and comparator models. Although some of these properties appear consistent with the system biology, fundamental questions remain about how the biological parameters are chosen if the cerebellar microcircuit applies a common computation to many distinct behavioral tasks. It is possible that the response profiles in classical conditioning of the eyeblink depend upon operant contingencies that have previously prevailed, for example in naturally occurring avoidance movements.

  18. Permissible Delay in Payments

    Directory of Open Access Journals (Sweden)

    Yung-Fu Huang

    2007-01-01

    Full Text Available The main purpose of this paper wants to investigate the optimal retailer's lot-sizing policy with two warehouses under partially permissible delay in payments within the economic order quantity (EOQ framework. In this paper, we want to extend that fully permissible delay in payments to the supplier would offer the retailer partially permissible delay in payments. That is, the retailer must make a partial payment to the supplier when the order is received. Then the retailer must pay off the remaining balance at the end of the permissible delay period. In addition, we want to add the assumption that the retailer's storage space is limited. That is, the retailer will rent the warehouse to store these exceeding items when the order quantity is larger than retailer's storage space. Under these conditions, we model the retailer's inventory system as a cost minimization problem to determine the retailer's optimal cycle time and optimal order quantity. Three theorems are developed to efficiently determine the optimal replenishment policy for the retailer. Finally, numerical examples are given to illustrate these theorems and obtained a lot of managerial insights.

  19. Asynchronous Bounded Expected Delay Networks

    CERN Document Server

    Bakhshi, Rena; Fokkink, Wan; Pang, Jun

    2010-01-01

    The commonly used asynchronous bounded delay (ABD) network models assume a fixed bound on message delay. We propose a probabilistic network model, called asynchronous bounded expected delay (ABE) model. Instead of a strict bound, the ABE model requires only a bound on the expected message delay. While the conditions of ABD networks restrict the set of possible executions, in ABE networks all asynchronous executions are possible, but executions with extremely long delays are less probable. In contrast to ABD networks, ABE networks cannot be synchronised efficiently. At the example of an election algorithm, we show that the minimal assumptions of ABE networks are sufficient for the development of efficient algorithms. For anonymous, unidirectional ABE rings of known size N we devise a probabilistic leader election algorithm having average message and time complexity O(N).

  20. 延迟间隔和提取条件对短时错误记忆的影响%The Research on the Influence of Delay Interval and Retrival Condition on Short-Term False Memory

    Institute of Scientific and Technical Information of China (English)

    陈红; 郭春彦; 杨海波

    2015-01-01

    This research explored the influnce of retrival condition and delay interval on short-term false memory with short-term DRM paradigm on a forced choice test. The results suggested short-term false memory were basically from the lost of store details access at retrival stage. That means delay interval could improve false memory without effective retrival. But on effective retrical condition, increased access of true memory trace could greatly reduce fasle memory and the effect of delay was not significant. The results of this experiment will enrich the theory of false memory.%采用短时DRM迫选任务,探讨提取条件和延迟间隔对短时错误记忆的影响,以进一步考察短时错误记忆的产生机制。结果发现,短时错误记忆的产生主要源于提取时对存贮细节通达的缺失。在无有效提取线索的条件下,延迟间隔能够增加错误记忆率;而有效提取线索存在时,真实记忆痕迹的可通达性增加能够极大避免错误记忆的产生,延迟间隔的作用则不显著。该实验的结果是对错误记忆理论解释的一种补充。

  1. Optimal Control with Time Delays via the Penalty Method

    Directory of Open Access Journals (Sweden)

    Mohammed Benharrat

    2014-01-01

    Full Text Available We prove necessary optimality conditions of Euler-Lagrange type for a problem of the calculus of variations with time delays, where the delay in the unknown function is different from the delay in its derivative. Then, a more general optimal control problem with time delays is considered. Main result gives a convergence theorem, allowing us to obtain a solution to the delayed optimal control problem by considering a sequence of delayed problems of the calculus of variations.

  2. Failure of α-MSH to delay extinction of conditioned avoidance behavior in rats with lesions in the parafascicular nuclei of the thalamus

    NARCIS (Netherlands)

    Bohus, B.; Wied, D. de

    1967-01-01

    Bilateral lesions in the thalamic parafascicular area facilitate the rate of extinction of a conditioned avoidance response without affecting avoidance learning. Treatment with long-acting α-MSH during extinction failed to affect the rate of extinction of the avoidance response. Since this peptide d

  3. Delay Independent Criterion for Multiple Time-delay Systems

    Science.gov (United States)

    Chang, C. J.; Liu, K. F. R.; Yeh, K.; Chen, C. W.; Chung, P. Y.

    Based on the fuzzy Lyapunov method, this work addresses the stability conditions for nonlinear systems with multiple time delays to ensure the stability of building structure control systems. The delay independent conditions are derived via the traditional Lyapunov and fuzzy Lyapunov methods for multiple time-delay systems as approximated by the Tagagi-Sugeno (T-S) fuzzy model. The fuzzy Lyapunov function is defined as a fuzzy blending of quadratic Lyapunov functions. A parallel distributed compensation (PDC) scheme is utilized to construct a global fuzzy logic control (FLC) by blending all linear local state feedback controllers in the controller design procedure. Furthermore, the H infinity performance and robustness of the design for modeling errors also need to be considered in the stability conditions.

  4. Delay-range-dependent chaos synchronization approach under varying time-lags and delayed nonlinear coupling.

    Science.gov (United States)

    Zaheer, Muhammad Hamad; Rehan, Muhammad; Mustafa, Ghulam; Ashraf, Muhammad

    2014-11-01

    This paper proposes a novel state feedback delay-range-dependent control approach for chaos synchronization in coupled nonlinear time-delay systems. The coupling between two systems is esteemed to be nonlinear subject to time-lags. Time-varying nature of both the intrinsic and the coupling delays is incorporated to broad scope of the present study for a better-quality synchronization controller synthesis. Lyapunov-Krasovskii (LK) functional is employed to derive delay-range-dependent conditions that can be solved by means of the conventional linear matrix inequality (LMI)-tools. The resultant control approach for chaos synchronization of the master-slave time-delay systems considers non-zero lower bound of the intrinsic as well as the coupling time-delays. Further, the delay-dependent synchronization condition has been established as a special case of the proposed LK functional treatment. Furthermore, a delay-range-dependent condition, independent of the delay-rate, has been provided to address the situation when upper bound of the delay-derivative is unknown. A robust state feedback control methodology is formulated for synchronization of the time-delay chaotic networks against the L2 norm bounded perturbations by minimizing the L2 gain from the disturbance to the synchronization error. Numerical simulation results are provided for the time-delay chaotic networks to show effectiveness of the proposed delay-range-dependent chaos synchronization methodologies. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  5. Controllability of delay systems with restrained controls

    Science.gov (United States)

    Chukwu, E. N.

    1979-01-01

    Using a geometric growth condition, both the function space and Euclidean controllability of a nonlinear delay system which has a compact and convex control set are characterized. This extends analogous results for ordinary differential systems, and it yields conditions under which perturbed nonlinear delay controllable systems are controllable.

  6. Classical conditioned responses to absent tones

    Directory of Open Access Journals (Sweden)

    Häusler Udo

    2006-08-01

    Full Text Available Abstract Background Recent evidence for a tight coupling of sensorimotor processes in trained musicians led to the question of whether this coupling extends to preattentively mediated reflexes; particularly, whether a classically conditioned response in one of the domains (auditory is generalized to another (tactile/motor on the basis of a prior association in a second-order Pavlovian paradigm. An eyeblink conditioning procedure was performed in 17 pianists, serving as a model for overlearned audiomotor integration, and 14 non-musicians. Results: During the training session, subjects were conditioned to respond to auditory stimuli (piano tones. During a subsequent testing session, when subjects performed keystrokes on a silent piano, pianists showed significantly higher blink rates than non-musicians. Conclusion These findings suggest a tight coupling of the auditory and motor domains in musicians, pointing towards training-dependent mechanisms of strong cross-modal sensorimotor associations even on sub-cognitive processing levels.

  7. Delay-dependent robust passivity control for uncertain time-delay systems

    Institute of Scientific and Technical Information of China (English)

    Li Guifang; Li Huiying; Yang Chengwu

    2007-01-01

    The robust passivity control problem is addressed for a class of uncertain delayed systems with timevarying delay. The parameter uncertainties are norm-bounded. First, the delay-dependent stability sufficient condition is obtained for the nominal system, and then, based-on the former, the delay-dependent robust passivity criteria is provided and the corresponding controller is designed in terms of linear matrix inequalities. Finally, a numerical example is given to demonstrate the validity of the proposed approach.

  8. Combined action of MK-801 and ceftriaxone impairs the acquisition and reinstatement of morphine-induced conditioned place preference,and delays morphine extinction in rats

    Institute of Scientific and Technical Information of China (English)

    Yaodong Fan; Haichen Niu; Joshua D.Rizak; Ling Li; Guimei Wang; Liqi Xu; He Ren; Hao Lei; Hualin Yu

    2012-01-01

    Objective It is well established that glutamate and its receptors,particularly the N-methyl-D-aspartate receptor (NMDAR),play a significant role in addiction and that the inhibition of glutamatergic hyperfunction reduces addictive behaviors in experimental animals.Specifically,NMDAR antagonists such as MK-801,and an inducer of the expression of glutamate transporter subtype-1 (GLT-1) (cefiriaxone) are known to inhibit addictive behavior.The purpose of this study was to determine whether the combined action of a low dose of MK-801 and a low dose of ceftriaxone provides better inhibition of the acquisition,extinction,and reinstatement of morphine-induced conditioned place preference (CPP) than either compound alone.Methods A morphine-paired CPP experiment was used to study the effects of low doses of MK-801,ceftriaxone and a combination of both on reward-related memory (acquisition,extinction,and reinstatement of morphine preference) in rats.Results A low dose of neither MK-801 (0.05 mg/kg,i.p.) nor ceftriaxone (25 mg/kg,i.p.) alone effectively impaired CPP behaviors.However,when applied in combination,they reduced the acquisition of morphine-induced CPP and completely prevented morphine reinstatement.Their combination also notably impaired the extinction of morphine-induced CPP.Conclusion The combined action of a low dose of an NMDAR antagonist (MK-801)and GLT-1 activation by ceftriaxone effectively changed different phases of CPP behavior.

  9. Measuring information-transfer delays.

    Directory of Open Access Journals (Sweden)

    Michael Wibral

    Full Text Available In complex networks such as gene networks, traffic systems or brain circuits it is important to understand how long it takes for the different parts of the network to effectively influence one another. In the brain, for example, axonal delays between brain areas can amount to several tens of milliseconds, adding an intrinsic component to any timing-based processing of information. Inferring neural interaction delays is thus needed to interpret the information transfer revealed by any analysis of directed interactions across brain structures. However, a robust estimation of interaction delays from neural activity faces several challenges if modeling assumptions on interaction mechanisms are wrong or cannot be made. Here, we propose a robust estimator for neuronal interaction delays rooted in an information-theoretic framework, which allows a model-free exploration of interactions. In particular, we extend transfer entropy to account for delayed source-target interactions, while crucially retaining the conditioning on the embedded target state at the immediately previous time step. We prove that this particular extension is indeed guaranteed to identify interaction delays between two coupled systems and is the only relevant option in keeping with Wiener's principle of causality. We demonstrate the performance of our approach in detecting interaction delays on finite data by numerical simulations of stochastic and deterministic processes, as well as on local field potential recordings. We also show the ability of the extended transfer entropy to detect the presence of multiple delays, as well as feedback loops. While evaluated on neuroscience data, we expect the estimator to be useful in other fields dealing with network dynamics.

  10. Conversion of linear time-invariant time-delay feedback systems into delay-differential equations with commensurate delays

    Science.gov (United States)

    Yamazaki, Tatsuya; Hagiwara, Tomomichi

    2014-08-01

    A new stability analysis method of time-delay systems (TDSs) called the monodromy operator approach has been studied under the assumption that a TDS is represented as a time-delay feedback system consisting of a finite-dimensional linear time-invariant (LTI) system and a pure delay. For applying this approach to TDSs described by delay-differential equations (DDEs), the problem of converting DDEs into representation as time-delay feedback systems has been studied. With regard to such a problem, it was shown that, under discontinuous initial functions, it is natural to define the solutions of DDEs in two different ways, and the above conversion problem was solved for each of these two definitions. More precisely, the solution of a DDE was represented as either the state of the finite-dimensional part of a time-delay feedback system or a part of the output of another time-delay feedback system, depending on which definition of the DDE solution one is talking about. Motivated by the importance in establishing a thorough relationship between time-delay feedback systems and DDEs, this paper discusses the opposite problem of converting time-delay feedback systems into representation as DDEs, including the discussions about the conversion of the initial conditions. We show that the state of (the finite-dimensional part of) a time-delay feedback system can be represented as the solution of a DDE in the sense of one of the two definitions, while its 'essential' output can be represented as that of another DDE in the sense of the other type of definition. Rigorously speaking, however, it is also shown that the latter representation is possible regardless of the initial conditions, while some initial condition could prevent the conversion into the former representation. This study hence establishes that the representation of TDSs as time-delay feedback systems possesses higher ability than that with DDEs, as description methods for LTI TDSs with commensurate delays.

  11. 工程项目延期总部管理费用索赔核算问题研究%Problem and Countermeasure of the Claim for Home Office Overhead Under the Condition of Engineering Project Delay

    Institute of Scientific and Technical Information of China (English)

    牛彦秀; 巩彦忠; 张天熹

    2015-01-01

    The Eichleay formula and Hudson formula are the methods which are used for calculating the amount of claim for home office overhead in the case of owner-caused delay. However,those two formulas are not perfect. To overcome their limitations,this paper provides an accounting model of activity-based costing,divide into direct and indirect home office overhead to refine engineering project accounting. This model establishes activity center,allocating resource cost according to resource drivers and allocating activity cost according to activity drivers. At last,a simplified case is given to explain the procedure. The accounting results can provide timely,reasonable and accurate evidences for the claim for home office overhead under the condition of engineering project delay.%核算工程项目因业主原因延期,企业索赔期间分摊总部管理费用采用的方法主要有Eichleay公式法和Hudson公式法,然而这两种方法都存在各自的局限性,为克服其缺陷,提出作业成本核算模式,区分直接和间接总部管理费用,细化工程项目核算,建立作业中心,按资源动因分配资源成本,按作业动因分配作业成本,以合理确定索赔额,并以案例形式演示核算程序。作业成本核算模式的核算结果可以为工程项目延期索赔总部管理费用提供及时、合理而准确的证据。

  12. Pseudotumoral delayed cerebral radionecrosis

    Energy Technology Data Exchange (ETDEWEB)

    Ciaudo-Lacroix, C.; Lapresle, J. (Centre Hospitalier de Bicetre, 94 - Le Kremlin-Bicetre (France))

    1985-01-01

    A 60 year-old woman with a scalp epithelioma underwent radiotherapy, the dose being 57 Gray. A first epileptic seizure occurred twenty months later. Neurological examination revealed signs of left hemisphere involvement. ..gamma..EG, angiography, CT scans, demonstrated a pseudotumoral avascular process. On account of the localisation, the patient being right-handed, no surgical procedure was performed. In spite of corticotherapy and anticonvulsive treatment, seizures recurred and neurological signs slowly progressed. The patient died, 22 months after the first seizure, of an associated disseminated carcinoma with cachexia. Neuropathological examination showed a massive lesion presenting all the features of delayed radionecrosis in the left hemisphere: situated mainly in the white matter; numerous vascular abnormalities; wide-spread demyelination; disappearance of oligoglial cells. The Authors recall the clinical and anatomical aspects of this condition for which the only successful treatment is surgical removal when location and size of the lesion permit. Finally, the mechanisms which have been proposed to explain this delayed cerebral radionecrosis are discussed.

  13. Isochronal synchronization of time delay and delay-coupled chaotic systems

    Energy Technology Data Exchange (ETDEWEB)

    Grzybowski, J M V; Yoneyama, T [Instituto Tecnologico de Aeronautica, ITA, Praca Marechal Eduardo Gomes, 50, Vila das Acacias, Sao Jose dos Campos, SP, Brazil, CEP 12.228-900 (Brazil); Macau, E E N, E-mail: zzmariovic@yahoo.com.br, E-mail: elbert@lac.inpe.br, E-mail: takashi@ita.br [Instituto Nacional de Pesquisas Espaciais, INPE, PO Box 515, Sao Jose dos Campos, SP, Brazil, CEP 12.227-010 (Brazil)

    2011-04-29

    This paper studies the problem of isochronal synchronization of time-delay chaotic systems featuring also coupling delay. Based on the Lyapunov-Krasovskii stability theory, sufficient conditions are derived for the stability of isochronal synchronization between a pair of identical chaotic systems. Such criteria permit the proper design of stable proportional linear feedback controller, more specifically, the design of adequate proportional feedback gain matrices. The proposed criteria are suited to systems with (i) intrinsic delay, (ii) coupling delay or (iii) both. Numerical simulations of the synchronization of delay-coupled systems are presented as examples of the application of the criteria.

  14. Delay synchronization of temporal Boolean networks

    Science.gov (United States)

    Wei, Qiang; Xie, Cheng-jun; Liang, Yi; Niu, Yu-jun; Lin, Da

    2016-01-01

    This paper investigates the delay synchronization between two temporal Boolean networks base on semi-tensor product method, which improve complete synchronization. Necessary and sufficient conditions for delay synchronization are drawn base on algebraic expression of temporal Boolean networks. A example is presented to show the effectiveness of theoretical analysis.

  15. ALMOST PERIODIC SOLUTIONS TO SOME NONLINEAR DELAY DIFFERENTIAL EQUATION

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The existence of an almost periodic solutions to a nonlinear delay diffierential equation is considered in this paper. A set of sufficient conditions for the existence and uniqueness of almost periodic solutions to some delay diffierential equations is obtained.

  16. The Right Delay

    NARCIS (Netherlands)

    Datadien, A.H.R.; Haselager, W.F.G.; Sprinkhuizen-Kuyper, I.G.

    2011-01-01

    Axonal conduction delays should not be ignored in simulations of spiking neural networks. Here it is shown that by using axonal conduction delays, neurons can display sensitivity to a specific spatio-temporal spike pattern. By using delays that complement the firing times in a pattern, spikes can ar

  17. An Analytical Delay Model

    Institute of Scientific and Technical Information of China (English)

    MIN Yinghua; LI Zhongcheng

    1999-01-01

    Delay consideration has been a majorissue in design and test of high performance digital circuits. Theassumption of input signal change occurring only when all internal nodesare stable restricts the increase of clock frequency. It is no longertrue for wave pipelining circuits. However, previous logical delaymodels are based on the assumption. In addition, the stable time of arobust delay test generally depends on the longest sensitizable pathdelay. Thus, a new delay model is desirable. This paper explores thenecessity first. Then, Boolean process to analytically describe thelogical and timing behavior of a digital circuit is reviewed. Theconcept of sensitization is redefined precisely in this paper. Based onthe new concept of sensitization, an analytical delay model isintroduced. As a result, many untestable delay faults under thelogical delay model can be tested if the output waveforms can be sampledat more time points. The longest sensitizable path length is computedfor circuit design and delay test.

  18. Sufficient Condition on Positive Periodic Solution for Neutral Delay Model%中立型时滞模型周期正解的一个充分条件

    Institute of Scientific and Technical Information of China (English)

    李琼; 曹进德

    2000-01-01

    A new sufficient conditions are derived for the existence of positive periodic solution ofneutral delay model of the formN′(t)=N(t)[ (t)- (t)N(t)-b(t)N(t- (t))-c(t)N′(t- (t))]where (t), (t), b(t), c(t), (t) are nonnegative continuous T-periodic functions, and the result in this paper answerthe open problem 9.2 in [1].%研究了一类中立型时滞模型:N′(t)=N(t)[ (t)- (t)N(t)-b(t)N(t-(t))-c(t)N′(t- (t))]周期正解的存在性,其中(t), (t),b(t),c(t),(t)是周期T的非负连续函数.一个新的充分条件被给出,这一结果肯定的回答了文[1]的分开问题9.2.

  19. Delay-dependent guaranteed cost control for uncertain systems with both state and input delays

    Institute of Scientific and Technical Information of China (English)

    Xuanfang YANG; Wuhua CHEN; Huajing FANG

    2004-01-01

    This paper considers the guaranteed cost control problem for a class of uncertain linear systems with both state and input delays.By representing the time-delay system in the descriptor system form and using a recent result on bounding of cross products of vectors,we obtain new delay-dependent sufficient conditions for the existence of the guaranteed cost controller in terms of linear matrix inequalities.Two examples are presented which show the effectiveness of our approach.

  20. Consensus networks with time-delays over finite fields

    Science.gov (United States)

    Li, Xiuxian; Su, Housheng; Chen, Michael Z. Q.

    2016-05-01

    In this paper, we investigate the consensus problem in networks with time-delays over finite fields. The delays are categorised into three cases: single constant delay, multiple constant delays, and time-varying bounded delays. For all cases, some sufficient and necessary conditions for consensus are derived. Furthermore, assuming that the communication graph is strongly connected, some of the obtained necessary conditions reveal that the conditions for consensus with time-delays over finite fields depend not only on the diagonal entries but also on the off-diagonal entries, something that is intrinsically distinct from the case over real numbers (where having at least one nonzero diagonal entry is a sufficient and necessary condition to guarantee consensus). In addition, it is shown that delayed networks cannot achieve consensus when the interaction graph is a tree if the corresponding delay-free networks cannot reach consensus, which is consistent with the result over real numbers. As for average consensus, we show that it can never be achieved for delayed networks over finite fields, although it indeed can be reached under several conditions for delay-free networks over finite fields. Finally, networks with time-varying delays are discussed and one sufficient condition for consensus is presented by graph-theoretic method.

  1. Delayed emergence after anesthesia.

    Science.gov (United States)

    Tzabazis, Alexander; Miller, Christopher; Dobrow, Marc F; Zheng, Karl; Brock-Utne, John G

    2015-06-01

    In most instances, delayed emergence from anesthesia is attributed to residual anesthetic or analgesic medications. However, delayed emergence can be secondary to unusual causes and present diagnostic dilemmas. Data from clinical studies is scarce and most available published material is comprised of case reports. In this review, we summarize and discuss less common and difficult to diagnose reasons for delayed emergence and present cases from our own experience or reference published case reports/case series. The goal is to draw attention to less common reasons for delayed emergence, identify patient populations that are potentially at risk and to help anesthesiologists identifying a possible cause why their patient is slow to wake up.

  2. A data-driven algorithm for offline pupil signal preprocessing and eyeblink detection in low-speed eye-tracking protocols.

    Science.gov (United States)

    Pedrotti, Marco; Lei, Shengguang; Dzaack, Jeronimo; Rötting, Matthias

    2011-06-01

    Event detection is the conversion of raw eye-tracking data into events--such as fixations, saccades, glissades, blinks, and so forth--that are relevant for researchers. In eye-tracking studies, event detection algorithms can have a serious impact on higher level analyses, although most studies do not accurately report their settings. We developed a data-driven eyeblink detection algorithm (Identification-Artifact Correction [I-AC]) for 50-Hz eye-tracking protocols. I-AC works by first correcting blink-related artifacts within pupil diameter values and then estimating blink onset and offset. Artifact correction is achieved with data-driven thresholds, and more reliable pupil data are output. Blink parameters are defined according to previous studies on blink-related visual suppression. Blink detection performance was tested with experimental data by visually checking the actual correspondence between I-AC output and participants' eye images, recorded by the eyetracker simultaneously with gaze data. Results showed a 97% correct detection percentage.

  3. Evidence that Illness-Compatible Cues Are Rewarding in Women Recovered from Anorexia Nervosa: A Study of the Effects of Dopamine Depletion on Eye-Blink Startle Responses

    Science.gov (United States)

    O’Hara, Caitlin B.; Keyes, Alexandra; Renwick, Bethany; Giel, Katrin E.; Campbell, Iain C.; Schmidt, Ulrike

    2016-01-01

    In anorexia nervosa (AN), motivational salience is attributed to illness-compatible cues (e.g., underweight and active female bodies) and this is hypothesised to involve dopaminergic reward circuitry. We investigated the effects of reducing dopamine (DA) transmission on the motivational processing of AN-compatible cues in women recovered from AN (AN REC, n = 17) and healthy controls (HC, n = 15). This involved the acute phenylalanine and tyrosine depletion (APTD) procedure and a startle eye-blink modulation (SEM) task. In a balanced amino acid state, AN REC showed an increased appetitive response (decreased startle potentiation) to illness-compatible cues (underweight and active female body pictures (relative to neutral and non-active cues, respectively)). The HC had an aversive response (increased startle potentiation) to the same illness-compatible stimuli (relative to neutral cues). Importantly, these effects, which may be taken to resemble symptoms observed in the acute stage of illness and healthy behaviour respectively, were not present when DA was depleted. Thus, AN REC implicitly appraised underweight and exercise cues as more rewarding than did HC and the process may, in part, be DA-dependent. It is proposed that the positive motivational salience attributed to cues of emaciation and physical activity is, in part, mediated by dopaminergic reward processes and this contributes to illness pathology. These observations are consistent with the proposal that, in AN, aberrant reward-based learning contributes to the development of habituation of AN-compatible behaviours. PMID:27764214

  4. Sensory prediction or motor control? Application of Marr-Albus type models of cerebellar function to classical conditioning

    Directory of Open Access Journals (Sweden)

    Nathan F Lepora

    2010-10-01

    Full Text Available Marr-Albus adaptive filter models of the cerebellum have been applied successfully to a range of sensory and motor control problems. Here we analyze their properties when applied to classical conditioning of the nictitating membrane response in rabbits. We consider a system-level model of eyeblink conditioning based on the anatomy of the eyeblink circuitry, comprising an adaptive filter model of the cerebellum, a comparator model of the inferior olive and a linear dynamic model of the nictitating membrane plant. To our knowledge, this is the first model that explicitly includes all these principal components, in particular the motor plant that is vital for shaping and timing the behavioral response. Model assumptions and parameters were systematically investigated to disambiguate basic computational capacities of the model from features requiring tuning of properties and parameter values. Without such tuning, the model robustly reproduced a range of behaviors related to sensory prediction, by displaying appropriate trial-level associative learning effects for both single and multiple stimuli, including blocking and conditioned inhibition. In contrast, successful reproduction of the real-time motor behavior depended on appropriate specification of the plant, cerebellum and comparator models. Although some of these properties appear consistent with the system biology, fundamental questions remain about how the biological parameters are chosen if the cerebellar microcircuit applies a common computation to many distinct behavioral tasks. It is possible that the response profiles in classical conditioning of the eyeblink depend upon operant contingencies that have previously prevailed, for example in naturally occurring avoidance movements.

  5. Contract delay: what is it and how are we performing?

    Directory of Open Access Journals (Sweden)

    David Finnie

    2012-02-01

    Research results about the level of contractor’s time management skills were analysed to determine the related impact on their ability to manage contract delays. A comparison was made between three conditions of contracts used in New Zealand to determine how delay management should be managed with a discussion about how the different contract conditions distribute risk among the parties. Recommendations were made to improve contract conditions, up-skill industry practitioners and ensure student graduates have adequate delay management skills.

  6. Adaptive synchronization of neural networks with time-varying delay and distributed delay

    Science.gov (United States)

    Wang, Kai; Teng, Zhidong; Jiang, Haijun

    2008-01-01

    In this paper, the adaptive synchronization of neural networks with time-varying delay and distributed delay is discussed. Based on the LaSalle invariant principle of functional differential equations and the adaptive feedback control technique, some sufficient conditions for adaptive synchronization of such a system are obtained. Finally, a numerical example is given to show the effectiveness of the proposed synchronization method.

  7. Controllability of Linear Discrete-Time Systems with Both Delayed States and Delayed Inputs

    Directory of Open Access Journals (Sweden)

    Hong Shi

    2013-01-01

    Full Text Available The controllability issues for discrete-time linear systems with delay in state and control are addressed. By introducing a new concept, the controllability realization index (CRI, the characteristic of controllability is revealed. An easily testable necessary and sufficient condition for the controllability of discrete-time linear systems with state and control delay is established.

  8. Delay-Dependent Exponential Stability Criterion for BAM Neural Networks with Time-Varying Delays

    Institute of Scientific and Technical Information of China (English)

    Wei-Wei Su; Yi-Ming Chen

    2008-01-01

    By employing the Lyapunov stability theory and linear matrix inequality (LMI) technique, delay dependent stability criterion is derived to ensure the exponential stability of bi-directional associative memory (BAM) neural networks with time-varying delays. The proposed condition can be checked easily by LMI control toolbox in Matlab. A numerical example is given to demonstrate the effectiveness of our results.

  9. A DELAY-DEPENDENT STABILITY CRITERION FOR NONLINEAR STOCHASTIC DELAY-INTEGRO-DIFFERENTIAL EQUATIONS

    Institute of Scientific and Technical Information of China (English)

    Niu Yuanling; Zhang Chengjian; Duan Jinqiao

    2011-01-01

    A type of complex systems under both random influence and memory effects is considered.The systems are modeled by a class of nonlinear stochastic delay-integrodifferential equations.A delay-dependent stability criterion for such equations is derived under the condition that the time lags are small enough.Numerical simulations are presented to illustrate the theoretical result.

  10. Delay-dependent robust H∞ control for uncertain fuzzy hyperbolic systems with multiple delays

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The robust H∞ control problem was considered for a class of fuzzy hyperbolic model (FHM) systems with parametric uncertainties and multiple delays. First, FHM modeling method was presented for time-delay nonlinear systems. Then, by using Lyapunov-Krasovskii approaches, delay-dependent sufficient condition for the existence of a kind of state feedback controller was proposed, which was expressed as linear matrix inequalities (LMIs). The controller can guarantee that the resulting closed-loop system is robustly asymptotically stable with a prescribed H∞ performance level for all admissible uncertainties and time-delay. Finally, a simulation example was provided to illustrate the effectiveness of the proposed approach.

  11. Adaptive global synchronization of a general complex dynamical network with non-delayed and delayed coupling

    Science.gov (United States)

    Wen, Sun; Chen, Shihua; Guo, Wanli

    2008-10-01

    This Letter investigates the global synchronization of a general complex dynamical network with non-delayed and delayed coupling. Based on Lasalle's invariance principle, adaptive global synchronization criteria is obtained. Analytical result shows that under the designed adaptive controllers, a general complex dynamical network with non-delayed and delayed coupling can globally asymptotically synchronize to a given trajectory. What is more, the node dynamic need not satisfy the very strong and conservative uniformly Lipschitz condition and the coupling matrix is not assumed to be symmetric or irreducible. Finally, numerical simulations are presented to verify the effectiveness of the proposed synchronization criteria.

  12. Adaptive global synchronization of a general complex dynamical network with non-delayed and delayed coupling

    Energy Technology Data Exchange (ETDEWEB)

    Wen Sun [College of Mathematics and Statistics, Wuhan University, Wuhan 430072 (China)], E-mail: sunwen_2201@163.com; Chen Shihua; Guo Wanli [College of Mathematics and Statistics, Wuhan University, Wuhan 430072 (China)

    2008-10-13

    This Letter investigates the global synchronization of a general complex dynamical network with non-delayed and delayed coupling. Based on Lasalle's invariance principle, adaptive global synchronization criteria is obtained. Analytical result shows that under the designed adaptive controllers, a general complex dynamical network with non-delayed and delayed coupling can globally asymptotically synchronize to a given trajectory. What is more, the node dynamic need not satisfy the very strong and conservative uniformly Lipschitz condition and the coupling matrix is not assumed to be symmetric or irreducible. Finally, numerical simulations are presented to verify the effectiveness of the proposed synchronization criteria.

  13. Multivariate Markov processes for stochastic systems with delays: application to the stochastic Gompertz model with delay.

    Science.gov (United States)

    Frank, T D

    2002-07-01

    Using the method of steps, we describe stochastic processes with delays in terms of Markov diffusion processes. Thus, multivariate Langevin equations and Fokker-Planck equations are derived for stochastic delay differential equations. Natural, periodic, and reflective boundary conditions are discussed. Both Ito and Stratonovich calculus are used. In particular, our Fokker-Planck approach recovers the generalized delay Fokker-Planck equation proposed by Guillouzic et al. The results obtained are applied to a model for population growth: the Gompertz model with delay and multiplicative white noise.

  14. Delayed feedback control of time-delayed chaotic systems: Analytical approach at Hopf bifurcation

    Energy Technology Data Exchange (ETDEWEB)

    Vasegh, Nastaran [Faculty of Electrical Engineering, K.N. Toosi University of Technology, PO Box 16315-1355, Tehran (Iran, Islamic Republic of)], E-mail: vasegh@eetd.kntu.ac.ir; Sedigh, Ali Khaki [Faculty of Electrical Engineering, K.N. Toosi University of Technology, PO Box 16315-1355, Tehran (Iran, Islamic Republic of)

    2008-07-28

    This Letter is concerned with bifurcation and chaos control in scalar delayed differential equations with delay parameter {tau}. By linear stability analysis, the conditions under which a sequence of Hopf bifurcation occurs at the equilibrium points are obtained. The delayed feedback controller is used to stabilize unstable periodic orbits. To find the controller delay, it is chosen such that the Hopf bifurcation remains unchanged. Also, the controller feedback gain is determined such that the corresponding unstable periodic orbit becomes stable. Numerical simulations are used to verify the analytical results.

  15. American Dream Delayed

    DEFF Research Database (Denmark)

    Khorunzhina, Natalia; Miller, Robert A.

    This paper investigates the delay in homeownership and a subsequent reduction in homeownership rate observed over the past decades. We focus on the delay in giving birth to children and increased labor market participation as contributing factors to homeownership dynamics for prime-age female hou...

  16. Delay-dependent robust H∞ controller design for a class of nonlinear uncertainty time-delay systems with input delay

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Based on an appropriate Lyapunov function,this paper analyzes the design of a delay-dependent robust H∞ state feedback control,with a focus on a class of non linear uncertainty linear time-delay systems with input delay using linear matrix inequalities.Under the condition that the nonlinear uncertain functions are gain bounded,a sufficient condition dependent on the delays of the state and input is presented for the existence of H∞ controller.The proposed controller not only stabilized closed-loop uncertain systems but also guaranteed a prescribed H∞ norm bound of closed-loop transfer matrix from the disturbance to controlled output.By solving a linear matrix inequation,we can obtain the robust H∞ controller.An example is given to show the effectiveness of the proposed method.

  17. Stabilization of a Nonlinear Delay System

    Directory of Open Access Journals (Sweden)

    Walid Arouri

    2012-01-01

    Full Text Available Problem statement: The analysis and control of delayed systems are becoming more and more research topics in progress. This is mainly due to the fact that the delay is frequently encountered in technological systems. This can affect their significantly operations. Most control command laws are based on current digital computers and delays are intrinsic to the process or in the control loop caused by the transmission time control sequences, or computing time. The delay may affect one or more states of the considered system. It may also affect the establishment of the command. Several studies have investigated the stability of delay systems under the assumption that the delay is a variable phenomenon; such variation is considered to be bounded or limited to facilitate analysis of the system. In this study we propose a modelling of delayed system by using the multimodels and switched system theory. The analysis of stability is based on the use of second Lyapunov method. The issued stability conditions are expressed as Bilinear Matrix Inequalities impossible to resolve. That’s why we propose the same original relaxations to come over this difficulty, an example of induction machine is given to illustrate over approach. Approach: We propose to use the control theory developed for switched systems to synthesis a control laws for the stabilisation of delays system. Results: We stabilize the induction machine around many operating points despite the non linearities. Conclusion: The developed method is less conservative and less pessimistic than the used classical methods.

  18. ON FEEDBACK CONTROL OF DELAYED CHAOTIC SYSTEM

    Institute of Scientific and Technical Information of China (English)

    李丽香; 彭海朋; 卢辉斌; 关新平

    2001-01-01

    In this paper two different types of feedback control technique are discussed: the standard feedback control and the time-delay feedback control which have been successfully used in many control systems. In order to understand to what extent the two different types of control technique are useful in delayed chaotic systems, some analytic stabilization conditions for chaos control from the two types of control technique are derived based on Lyapunov stabilization arguments. Similarly, we discuss the tracking problem by applying the time-delay feedback control. Finally, numerical examples are provided.

  19. Discriminações condicionais após treino de pareamento consistente de estímulos complexos com atraso Conditional discrimination following complex stimulus consistency training with delay

    Directory of Open Access Journals (Sweden)

    Grauben José Alves de Assis

    2006-08-01

    Full Text Available O objetivo do presente estudo foi verificar a formação de discriminações condicionais por meio de um procedimento de treino por pareamento consistente de estímulos complexos com atraso. Na Fase I, com cinco universitários, foi realizado o Pré-treino TX e Treinos de Aquisição AE, BF e DC envolvendo estímulos modelos e de comparação simples. Na Fase II, houve o Pré-treino MN-O/P, os Treinos AB-E/F e AD-C/F, num formato de pareamento consistente. Esses treinos foram intercalados aos Testes de Transitividade e de Equivalência EF/FE, CF/FC, BD/DB, com estímulos modelos complexos e de comparação simples. Na Fase III, os Treinos AB-E/F e AD-C/F foram desmembrados em AB-E, AB-F e AD-C e reaplicados os mesmos testes. Todos os participantes formaram as relações condicionais entre estímulos modelos simples e complexos, embora com variabilidade quanto à exposição aos blocos de tentativas. Houve variabilidade em termos de formação das relações emergentes testadas. Os resultados sugerem que o procedimento utilizado produziu discriminações condicionais e levou à formação de classes de estímulos equivalentes, não obstante a variabilidade referida. A busca de fontes de controle mais eficazes se faz necessária em pesquisas futuras.The aim of this investigation was to assess the formation of conditional discriminations by means of a procedure involving complex stimulus training with delay. In phase I five university students received a pretraining TX trial followed by AE, BF and DC acquisition training involving matching-to-sample and simple comparison. In phase II a pretraining N-O/P, the training AB-E/F, and AD-C/F, with consistency training. These training trials were interspersed with EF/FE, CF/FC, and BD/DB transitivity and equivalence tests following complex matching-to-sample and simple comparison. In phase III AB-E/F and AD-CF trials occurred jointly with AB-E, AB-F and AD-C sequences, followed by transitivity and

  20. Delay-dependent stabilization of singular Markovian jump systems with state delay

    Institute of Scientific and Technical Information of China (English)

    Zhengguang WU; Hongye SU; Jian CHU

    2009-01-01

    This paper deals with the delay-dependent stabilization problem for singular systems with Markovian jump parameters and time delays.A delay-dependent condition is established for the considered system to be regular,impulse free and stochastically stable.Based on the condition,a design algorithm of the desired state feedback controller which guarantees the resultant closed-loop system to be regular,impulse free and stochastically stable is proposed in terms of a set of strict linear matrix inequalities (LMIs).Numerical examples show the effectiveness of the proposed methods.

  1. Delay-Dependent H∞ Filtering for Singular Time-Delay Systems

    Directory of Open Access Journals (Sweden)

    Zhenbo Li

    2011-01-01

    Full Text Available This paper deals with the problem of delay-dependent H∞ filtering for singular time-delay systems. First, a new delay-dependent condition which guarantees that the filter error system has a prescribed H∞ performance γ is given in terms of linear matrix inequalities (LMIs. Then, the sufficient condition is obtained for the existence of the H∞ filter, and the explicit expression for the desired H∞ filter is presented by using LMIs and the cone complementarity linearization iterative algorithm. A numerical example is provided to illustrate the effectiveness of the proposed method.

  2. Delay-dependent robust H∞ control for uncertain discrete time-delay fuzzy systems

    Institute of Scientific and Technical Information of China (English)

    Gong Cheng; Su Baoku

    2009-01-01

    The robust H∞ control problem of norm bounded uncertain discrete Takagi-Sugeno (T-S) fuzzy tems with state delay is addressed. First, by constructing an appropriate basis-dependent Lyapunov-Krasovskii function, a new delay-dependent sufficient condition on robust H∞-disturbance attenuation is presented, in which both robust stability and prescribed H∞ performance are guaranteed to be achieved. Then based on the condition, a delay-dependent robust H∞ controller design scheme is developed in term of a convex algorithm. Finally, examples are given to illustrate the effectiveness of the proposed method.

  3. commensurate point delays

    Directory of Open Access Journals (Sweden)

    M. de la Sen

    2005-01-01

    nominal controller is maintained. In the current approach, the finite spectrum assignment is only considered as a particular case of the designer's choice of a (delay-dependent arbitrary spectrum assignment objective.

  4. Contract delay: what is it and how are we performing?

    Directory of Open Access Journals (Sweden)

    David Finnie

    2012-02-01

    Full Text Available AbstractThis paper examines the management of contract delays in the construction industry as currently practised, and suggests some best practice alternative methods.Research results about the level of contractor’s time management skills were analysed to determine the related impact on their ability to manage contract delays. A comparison was made between three conditions of contracts used in New Zealand to determine how delay management should be managed with a discussion about how the different contract conditions distribute risk among the parties. Recommendations were made to improve contract conditions, up-skill industry practitioners and ensure student graduates have adequate delay management skills.

  5. Time Delay Cosmography

    OpenAIRE

    Treu, Tommaso; Marshall, Philip J.

    2016-01-01

    Gravitational time delays, observed in strong lens systems where the variable background source is multiply-imaged by a massive galaxy in the foreground, provide direct measurements of cosmological distance that are very complementary to other cosmographic probes. The success of the technique depends on the availability and size of a suitable sample of lensed quasars or supernovae, precise measurements of the time delays, accurate modeling of the gravitational potential of the main deflector,...

  6. Delayed diagnosis of narcolepsy: characterization and impact.

    Science.gov (United States)

    Thorpy, Michael J; Krieger, Ana C

    2014-05-01

    Narcolepsy, a chronic neurologic condition resulting from dysregulation of the sleep-wake cycle, usually has an onset at an early age. However, a long delay until diagnosis has been consistently reported in the literature across countries and several publications have focused on characterizing this delay. Most studies report a mean delay to diagnosis of up to 15 years, with individual cases of >60 years, although a trend over time toward a shorter diagnostic delay has been suggested. While variables associated with this delay have been identified, a lack of symptom recognition resulting in misdiagnosis prior to reaching the narcolepsy diagnosis is the likely underlying reason. This lack of symptom recognition is especially relevant considering the high comorbidity burden that has been shown in patients with narcolepsy as some disorders manifest with symptoms that overlap with narcolepsy. A consequence of delayed diagnosis is delayed treatment, which affects the burden of disease. Substantial detrimental effects on health-care resource utilization, employment, and quality of life have been described after narcolepsy onset and prior to the diagnosis of narcolepsy. This review highlights the importance of closing the diagnostic gap by expanding awareness of narcolepsy and its symptoms.

  7. Semi-Discretization for Time-Delay Systems

    CERN Document Server

    Insperger, Tamás

    2011-01-01

    This book presents the recently introduced and already widely referred semi-discretization method for the stability analysis of delayed dynamical systems. Delay differential equations often come up in different fields of engineering, like feedback control systems, machine tool vibrations, balancing/stabilization with reflex delay. The behavior of such systems is often counter-intuitive and closed form analytical formulas can rarely be given even for the linear stability conditions. If parametric excitation is coupled with the delay effect, then the governing equation is a delay differential eq

  8. New synchronization analysis for complex networks with variable delays

    Institute of Scientific and Technical Information of China (English)

    Zhang Hua-Guang; Gong Da-Wei; Wang Zhan-Shan

    2011-01-01

    This paper deals with the issue of synchronization of delayed complex networks. Differing from previous results, the delay interval[0, d(t)]is divided into some variable subintervals by employing a new method of weighting delays. Thus,new synchronization criteria for complex networks with time-varying delays are derived by applying this weighting-delay method and introducing some free weighting matrices. The obtained results have proved to be less conservative than previous results. The sufficient conditions of asymptotical synchronization are derived in the form of linear matrix inequality, which are easy to verify. Finally, several simulation examples axe provided to show the effectiveness of the proposed results.

  9. Locomotive Assignment Optimization Including Train Delays

    Directory of Open Access Journals (Sweden)

    Sandra Kasalica

    2013-10-01

    Full Text Available Intention– Cyclic locomotive assignment planning is a specific type of organization of locomotive usage, and in fact, it means putting the complete workload to a closed chain, which is repeated periodically. The concept of cyclic locomotive assignment planning type organization in the area of train traction has proven in practice as the best one, but as it is made for in-advance defined timetable and without considering the stochastic nature of the timetable realization process, it leads to incompatibility in using locomotives. Methodology – Methodology defined in this paper contains: research of train delays on the Serbian Railways and Montenegrin Railways networks, analysis of the real system organization of locomotive usage in conditions of train delays, theoretical thesis of solving the problem of optimal cyclic locomotive assignment planning in conditions of train delays, designing of a model with algorithms, preparing the software package, testing the model and program with results, as well as the conclusions drawn from the complete research project. Results– The optimization model of cyclic locomotive assignment planning during the process of making timetable including train delays has been defined. Conclusion –The obtained results have shown as expected, that the larger delays of trains required a larger number of locomotives. However, by using this model it is possible to optimize the required number of locomotives, taking into account the real time delays of trains.

  10. The Economic Promise of Delayed Aging.

    Science.gov (United States)

    Goldman, Dana

    2015-12-18

    Biomedicine has made enormous progress in the last half century in treating common diseases. However, we are becoming victims of our own success. Causes of death strongly associated with biological aging, such as heart disease, cancer, Alzheimer's disease, and stroke-cluster within individuals as they grow older. These conditions increase frailty and limit the benefits of continued, disease-specific improvements. Here, we show that a "delayed-aging" scenario, modeled on the biological benefits observed in the most promising animal models, could solve this problem of competing risks. The economic value of delayed aging is estimated to be $7.1 trillion over 50 years. Total government costs, including Social Security, rise substantially with delayed aging--mainly caused by longevity increases--but we show that these can be offset by modest policy changes. Expanded biomedical research to delay aging appears to be a highly efficient way to forestall disease and extend healthy life.

  11. Stability analysis in a car-following model with reaction-time delay and delayed feedback control

    Science.gov (United States)

    Jin, Yanfei; Xu, Meng

    2016-10-01

    The delayed feedback control in terms of both headway and velocity differences has been proposed to guarantee the stability of a car-following model including the reaction-time delay of drivers. Using Laplace transformation and transfer function, the stable condition is derived and appropriate choices of time delay and feedback gains are designed to stabilize traffic flow. Meanwhile, an upper bound on explicit time delay is determined with respect to the response of desired acceleration. To ensure the string stability, the explicit time delay cannot over its upper bound. Numerical simulations indicate that the proposed control method can restraint traffic congestion and improve control performance.

  12. Global Synchronization of General Delayed Dynamical Networks

    Institute of Scientific and Technical Information of China (English)

    LI Zhi

    2007-01-01

    Global synchronization of general delayed dynamical networks with linear coupling are investigated. A sufficient condition for the global synchronization is obtained by using the linear matrix inequality and introducing a reference state. This condition is simply given based on the maximum nonzero eigenvalue of the network coupling matrix. Moreover, we show how to construct the coupling matrix to guarantee global synchronization of network,which is very convenient to use. A two-dimension system with delay as a dynamical node in network with global coupling is finally presented to verify the theoretical results of the proposed global synchronization scheme.

  13. Time Delay Cosmography

    CERN Document Server

    Treu, Tommaso

    2016-01-01

    Gravitational time delays, observed in strong lens systems where the variable background source is multiply-imaged by a massive galaxy in the foreground, provide direct measurements of cosmological distance that are very complementary to other cosmographic probes. The success of the technique depends on the availability and size of a suitable sample of lensed quasars or supernovae, precise measurements of the time delays, accurate modeling of the gravitational potential of the main deflector, and our ability to characterize the distribution of mass along the line of sight to the source. We review the progress made during the last 15 years, during which the first competitive cosmological inferences with time delays were made, and look ahead to the potential of significantly larger lens samples in the near future.

  14. Prediction of delayed subsidence

    Science.gov (United States)

    Burns, K.

    A predictive model of delayed subsidence is discussed. A numerical implementation is tested on one of the best-described study areas, Allegheny County in Pennsylvania. In planning insurance of restitution measures, a predictive model is of value in estimating the magnitude of the problem and the size of long-term budgetary commitments. Contrary to active subsidence, which occurs concurrently with mining operations, or is completed within a few days following coal extraction, delayed subsidence may take many years to appear at the surface after coal mines are abandoned. There are two principal morphological types of delayed subsidence: troughs, which are shallow depressions, and sinks, which are steep-sided crown pits. Both types are damaging to surface structures, and a variety of methods were introduced to deal with the problem, ranging from subsidence insurance to site restitution.

  15. Time delay cosmography

    Science.gov (United States)

    Treu, Tommaso; Marshall, Philip J.

    2016-07-01

    Gravitational time delays, observed in strong lens systems where the variable background source is multiply imaged by a massive galaxy in the foreground, provide direct measurements of cosmological distance that are very complementary to other cosmographic probes. The success of the technique depends on the availability and size of a suitable sample of lensed quasars or supernovae, precise measurements of the time delays, accurate modeling of the gravitational potential of the main deflector, and our ability to characterize the distribution of mass along the line of sight to the source. We review the progress made during the last 15 years, during which the first competitive cosmological inferences with time delays were made, and look ahead to the potential of significantly larger lens samples in the near future.

  16. Delayed Random Relays

    CERN Document Server

    Ohira, Toru

    2016-01-01

    We present here a system with collection of random walks relaying a signal in one dimension with a presence of a delay. We are interested in the time for a signal to travel from one end (start) to the other end (finish) of the lined group of random walkers. It is found that there is an optimal number of walkers for the signal to travel fastest if the delay is present. We discuss implications of this model and associated behaviors to physical and biological systems.

  17. Approximation of distributed delays

    CERN Document Server

    Lu, Hao; Eberard, Damien; Simon, Jean-Pierre

    2010-01-01

    We address in this paper the approximation problem of distributed delays. Such elements are convolution operators with kernel having bounded support, and appear in the control of time-delay systems. From the rich literature on this topic, we propose a general methodology to achieve such an approximation. For this, we enclose the approximation problem in the graph topology, and work with the norm defined over the convolution Banach algebra. The class of rational approximates is described, and a constructive approximation is proposed. Analysis in time and frequency domains is provided. This methodology is illustrated on the stabilization control problem, for which simulations results show the effectiveness of the proposed methodology.

  18. Delay Bounds for Multiclass FIFO

    OpenAIRE

    Jiang, Yuming; Misra, Vishal

    2016-01-01

    FIFO is perhaps the simplest scheduling discipline. For single-class FIFO, its delay guarantee performance has been extensively studied: The well-known results include a stochastic delay bound for $GI/GI/1$ by Kingman and a deterministic delay bound for $D/D/1$ by Cruz. However, for multiclass FIFO, few such results are available. To fill the gap, we prove delay bounds for multiclass FIFO in this work, considering both deterministic and stochastic cases. Specifically, delay bounds are present...

  19. Delay-dependent robust stabilization for uncertain singular:systems with discrete and distributed delays

    Institute of Scientific and Technical Information of China (English)

    Zhengguang WU; Wuneng ZHOU

    2008-01-01

    This paper investigates the problem of delay-dependent robust stabilization for uncertain singular systems with discrete and distributed delays in terms of linear matrix inequality(LMI)approach.Based on a delay-dependent stability condition for the nominal system,a state feedback controller is designed,which guarantees the resultant closedloop system to be robustly stable.An explicit expression for the desired controller is also given by solving a set of matrix inequalities.Some numerical examples are provided to illustrate the less conservativeness of the proposed methods.

  20. Interval estimation for uncertain systems with time-varying delays

    Science.gov (United States)

    Efimov, Denis; Perruquetti, Wilfrid; Richard, Jean-Pierre

    2013-10-01

    The estimation problem for uncertain time-delay systems is addressed. A design method of reduced-order interval observers is proposed. The observer estimates the set of admissible values (the interval) for the state at each instant of time. The cases of known fixed delays and uncertain time-varying delays are analysed. The proposed approach can be applied to linear delay systems and nonlinear time-delay systems in the output canonical form. It involves the properties of quasi-monotone/Metzler/cooperative systems. In this framework, it is shown that if under a suitable coordinate transformation the delay-free subsystem is cooperative, then the delayed estimation error dynamics inherits this property. The conditions to find the observer gains are formulated in the form of LMI. The framework efficiency is demonstrated on examples of nonlinear systems.

  1. Mode and delay-dependent adaptive exponential synchronization in pth moment for stochastic delayed neural networks with Markovian switching.

    Science.gov (United States)

    Zhou, Wuneng; Tong, Dongbing; Gao, Yan; Ji, Chuan; Su, Hongye

    2012-04-01

    In this brief, the analysis problem of the mode and delay-dependent adaptive exponential synchronization in th moment is considered for stochastic delayed neural networks with Markovian switching. By utilizing a new nonnegative function and the -matrix approach, several sufficient conditions to ensure the mode and delay-dependent adaptive exponential synchronization in th moment for stochastic delayed neural networks are derived. Via the adaptive feedback control techniques, some suitable parameters update laws are found. To illustrate the effectiveness of the -matrix-based synchronization conditions derived in this brief, a numerical example is provided finally.

  2. Delayed breast implant reconstruction

    DEFF Research Database (Denmark)

    Hvilsom, Gitte B.; Hölmich, Lisbet R.; Steding-Jessen, Marianne;

    2012-01-01

    We evaluated the association between radiation therapy and severe capsular contracture or reoperation after 717 delayed breast implant reconstruction procedures (288 1- and 429 2-stage procedures) identified in the prospective database of the Danish Registry for Plastic Surgery of the Breast during...... reconstruction approaches other than implants should be seriously considered among women who have received radiation therapy....

  3. Delayed traumatic diaphragmatic hernia

    Science.gov (United States)

    Lu, Jing; Wang, Bo; Che, Xiangming; Li, Xuqi; Qiu, Guanglin; He, Shicai; Fan, Lin

    2016-01-01

    Abstract Background: Traumatic diaphragmatic hernias (TDHs) are sometimes difficult to identify at an early stage and can consequently result in diagnostic delays with life-threatening outcomes. It is the aim of this case study to highlight the difficulties encountered with the earlier detection of traumatic diaphragmatic hernias. Methods: Clinical data of patients who received treatment for delayed traumatic diaphragmatic hernias in registers of the First Affiliated Hospital of Xi’an Jiaotong University from 1998 to 2014 were analyzed retrospectively. Results: Six patients were included in this study. Left hemidiaphragm was affected in all of them. Most of the patients had a history of traffic accident and 1 a stab-penetrating injury. The interval from injury to developing symptoms ranged from 2 to 11 years (median 5 years). The hernial contents included the stomach, omentum, small intestine, and colon. Diaphragmatic injury was missed in all of them during the initial managements. All patients received operations once the diagnosis of delayed TDH was confirmed, and no postoperative mortality was detected. Conclusions: Delayed TDHs are not common, but can lead to serious consequences once occurred. Early detection of diaphragmatic injuries is crucial. Surgeons should maintain a high suspicion for injuries of the diaphragm in cases with abdominal or lower chest traumas, especially in the initial surgical explorations. We emphasize the need for radiographical follow-up to detect diaphragmatic injuries at an earlier stage. PMID:27512848

  4. 'No delays achiever'.

    Science.gov (United States)

    2007-05-01

    The latest version of the NHS Institute for Innovation and Improvement's 'no delays achiever', a web based tool created to help NHS organisations achieve the 18-week target for GP referrals to first treatment, is available at www.nodelaysachiever.nhs.uk.

  5. Delay-Dependent Asymptotic Stability of Cohen-Grossberg Models with Multiple Time-Varying Delays

    Directory of Open Access Journals (Sweden)

    Xiaofeng Liao

    2007-01-01

    Full Text Available Dynamical behavior of a class of Cohen-Grossberg models with multiple time-varying delays is studied in detail. Sufficient delay-dependent criteria to ensure local and global asymptotic stabilities of the equilibrium of this network are derived by constructing suitable Lyapunov functionals. The obtained conditions are shown to be less conservative and restrictive than those reported in the known literature. Some numerical examples are included to demonstrate our results.

  6. Effect of Small Transmission Delay on Human Behavior in Audio Communication

    Science.gov (United States)

    Ohnishi, Hitoshi; Mochizuki, Kaname

    Transmission delay in audio communications is a well-known obstacle to achieving smooth communication. However, it is not known what kinds of effects are caused by small delays. We hypothesized that the small delay in the listener's responses disturbs the speaker's “verbal conditioning, ” where the verbal behavior of the speaker varies in accordance with the listener's responses. We examined whether the small delays in the listener's responses disturb the speaker's verbal conditioning using an artificial-grammar learning task. The results suggested that a 300-ms delay disturbed the participants' verbal conditioning although they were not adequately aware of the delay.

  7. Delayed fluorescence in photosynthesis.

    Science.gov (United States)

    Goltsev, Vasilij; Zaharieva, Ivelina; Chernev, Petko; Strasser, Reto J

    2009-01-01

    Photosynthesis is a very efficient photochemical process. Nevertheless, plants emit some of the absorbed energy as light quanta. This luminescence is emitted, predominantly, by excited chlorophyll a molecules in the light-harvesting antenna, associated with Photosystem II (PS II) reaction centers. The emission that occurs before the utilization of the excitation energy in the primary photochemical reaction is called prompt fluorescence. Light emission can also be observed from repopulated excited chlorophylls as a result of recombination of the charge pairs. In this case, some time-dependent redox reactions occur before the excitation of the chlorophyll. This delays the light emission and provides the name for this phenomenon-delayed fluorescence (DF), or delayed light emission (DLE). The DF intensity is a decreasing polyphasic function of the time after illumination, which reflects the kinetics of electron transport reactions both on the (electron) donor and the (electron) acceptor sides of PS II. Two main experimental approaches are used for DF measurements: (a) recording of the DF decay in the dark after a single turnover flash or after continuous light excitation and (b) recording of the DF intensity during light adaptation of the photosynthesizing samples (induction curves), following a period of darkness. In this paper we review historical data on DF research and recent advances in the understanding of the relation between the delayed fluorescence and specific reactions in PS II. An experimental method for simultaneous recording of the induction transients of prompt and delayed chlorophyll fluorescence and decay curves of DF in the millisecond time domain is discussed.

  8. Stability Analysis of Uncertain Discrete Time-Delay Control Systems

    Institute of Scientific and Technical Information of China (English)

    Long Xuming; Duan Ping

    2006-01-01

    Based on Lyapunov stability theory, a less conservative sufficient conditions for the stabilities of uncertain discrete delay-independent and delay-dependent control systems are obtained by using the linear matrix inequality (LMI) approach. Judgement of the stability of time-delay systems is transformed to judgement of the feasible solution of an LMI, and hence is solved by use of MATLAB. Numerical simulations verify the validity of the proposed method.

  9. The K-Stability of Nonlinear Delay Systems

    Institute of Scientific and Technical Information of China (English)

    章毅; 张毅; 王联

    1994-01-01

    In this paper,we study the K-stability theory of nonlinear delay systems.In the more general case,we establish two nonlinear delay differential inequalities.Therefore,to study the X-stability,a powerful method is provided.By making use of the foregoing inequalities,we analyse and investigate some K-stabiiity conditions of nonlinear delay systems.Finally,some examples are given to illustrate our theory.

  10. Periodic Solutions of Multispecies Mutualism System with Infinite Delays

    Directory of Open Access Journals (Sweden)

    Wenbo Zhao

    2014-01-01

    Full Text Available We studied the delayed periodic mutualism system with Gilpin-Ayala effect. Some new and interesting sufficient conditions are obtained to guarantee the existence of periodic solution for the multispecies mutualism system with infinite delays. Our method is based on Mawhin's coincidence degree. To the best knowledge of the authors, there is no paper considering the existence of periodic solutions for n-species mutualism system with infinite delays.

  11. Pigeons' Discounting of Probabilistic and Delayed Reinforcers

    Science.gov (United States)

    Green, Leonard; Myerson, Joel; Calvert, Amanda L.

    2010-01-01

    Pigeons' discounting of probabilistic and delayed food reinforcers was studied using adjusting-amount procedures. In the probability discounting conditions, pigeons chose between an adjusting number of food pellets contingent on a single key peck and a larger, fixed number of pellets contingent on completion of a variable-ratio schedule. In the…

  12. Quasi-Hyperbolicity and Delay Semigroups

    Directory of Open Access Journals (Sweden)

    Shard Rastogi

    2016-01-01

    Full Text Available We study quasi-hyperbolicity of the delay semigroup associated with the equation u′(t=Bu(t+Φut, where ut is the history function and (B,D(B is the generator of a quasi-hyperbolic semigroup. We give conditions under which the associated solution semigroup of this equation generates a quasi-hyperbolic semigroup.

  13. Imperative Causes of Delays in Construction Projects from Developers’ Outlook

    Directory of Open Access Journals (Sweden)

    Othuman Mydin M.A.

    2014-03-01

    Full Text Available Project delays in the construction industry are a universal or large-scale observable fact affecting not only the construction industry but the overall economy of countries as well. As far as the Malaysian construction industry is concerned, project delays are common problems in the construction industry, particularly in housing development. The objective of this study is to evaluate and identify the causes and the consequences of project delays in private housing development projects in Malaysia, and the remedies that can minimize these delays. The top ten causes of delays are weather conditions, poor site conditions, poor site management, incomplete documents, lack of experience, financial problems, contract modifications, delay in the approval of major variations, contractor coordination problems with other parties, and construction mistakes and defective works. It has been analysed that the causes of the delays point to the contractor factors, which contribute to the major factors that cause project delays in private housing development projects. The consequences of the delays include time overrun, cost overrun, differences in opinion, negotiations, legal actions and total abandonment. Herewith are presented some recommendations to minimize these project delays.

  14. CS-dependent response probability in an auditory masked-detection task: considerations based on models of Pavlovian conditioning.

    Science.gov (United States)

    Mason, Christine R; Idrobo, Fabio; Early, Susan J; Abibi, Ayome; Zheng, Ling; Harrison, J Michael; Carney, Laurel H

    2003-05-01

    Experimental studies were performed using a Pavlovian-conditioned eyeblink response to measure detection of a variable-sound-level tone (T) in a fixed-sound-level masking noise (N) in rabbits. Results showed an increase in the asymptotic probability of conditioned responses (CRs) to the reinforced TN trials and a decrease in the asymptotic rate of eyeblink responses to the non-reinforced N presentations as a function of the sound level of the T. These observations are consistent with expected behaviour in an auditory masked detection task, but they are not consistent with predictions from a traditional application of the Rescorla-Wagner or Pearce models of associative learning. To implement these models, one typically considers only the actual stimuli and reinforcement on each trial. We found that by considering perceptual interactions and concepts from signal detection theory, these models could predict the CS dependence on the sound level of the T. In these alternative implementations, the animals response probabilities were used as a guide in making assumptions about the "effective stimuli".

  15. Delay Analysis for Wireless Local Area Networks with Multipacket Reception under Finite Load

    CERN Document Server

    Zhang, Ying Jun; Chen, Darui

    2008-01-01

    To date, most analysis of WLANs has been focused on their operation under saturation condition. This work is an attempt to understand the fundamental performance of WLANs under unsaturated condition. In particular, we are interested in the delay performance when collisions of packets are resolved by an exponential backoff mechanism. Using a multiple-vacation queueing model, we derive an explicit expression for packet delay distribution, from which necessary conditions for finite mean delay and delay jitter are established. It is found that under some circumstances, mean delay and delay jitter may approach infinity even when the traffic load is way below the saturation throughput. Saturation throughput is therefore not a sound measure of WLAN capacity when the underlying applications are delay sensitive. To bridge the gap, we define safe-bounded-mean-delay (SBMD) throughput and safe-bounded-delay-jitter (SBDJ) throughput that reflect the actual network capacity users can enjoy when they require bounded mean de...

  16. On Delay Independent Stabilization Analysis for a Class of Switched Large-Scale Time-Delay Systems

    Directory of Open Access Journals (Sweden)

    Chi-Jo Wang

    2013-01-01

    Full Text Available In view of the state-driven switching method, the sufficient stability conditions with delay independence will be derived for the switched large-scale time-delay systems. A new stability criterion of switched large-scale time-delay systems is deduced by Lyapunov stability theorem. The method can be applied to cases when all individual switched systems are unstable. Finally, one example is exploited to illustrate the proposed schemes.

  17. Robust H∞ Control of Uncertain T-S Fuzzy Time-Delay System: A Delay Decomposition Approach

    OpenAIRE

    Cheng Gong; Chunsong Han

    2013-01-01

    This paper is concerned with the problem of robust H∞ control for a class of uncertain time-delay fuzzy systems with norm-bounded parameter uncertainties. By utilizing the instrumental idea of delay decomposition, the decomposed Lyapunov-Krasovskii functional is introduced to uncertain T-S fuzzy system, and some delay-dependent conditions for the existence of robust controller are formulated in the form of linear matrix inequalities (LMIs). When these LMIs are feasible, a controller is presen...

  18. Elite athletes and pubertal delay.

    Science.gov (United States)

    Kapczuk, Karina

    2017-10-01

    Intensive physical training and participation in competitive sports during childhood and early adolescence may affect athletes' pubertal development. On the other hand, pubertal timing, early or late, may impact on an athlete selection for a particular sport. Genetic predisposition, training load, nutritional status and psychological stress determine athletes' pubertal timing. Athletes that practice esthetic sports, especially gymnasts, are predisposed to a delay in pubertal development. The growing evidence indicates that energy deficiency, not a systemic training per se, plays a crucial role in the pathogenesis of functional hypothalamic hypogonadism in female athletes. Metabolic and psychologic stress activate hypothalamic-pituitary-adrenal axis and suppress hypothalamic-pituitary-ovarian axis. Female athletes who do not begin secondary sexual development by the age of 14 or menstruation by the age of 16 warrant a comprehensive evaluation and a targeted treatment. Somatic growth and sexual maturation of elite female athletes are largely sport-specific since each sport favors a particular somatotype and requires a specific training. Chronic negative energy balance resulting from a systemic physical training and inadequate energy intake may delay pubertal development in elite athletes. Youth athletes, especially those engaged in competitive sports that emphasize prepubertal or lean appearance, are at risk of developing relative energy deficiency in sport associated with disordered eating or eating disorders. Management strategies should address the complex conditions underlying functional hypothalamic hypogonadism.

  19. [Striated and delayed nephrography].

    Science.gov (United States)

    Marlois, O; Padovani, J; Faure, F; Devred, P; Grangier, M L; Panuel, M

    1985-10-01

    About a case of striated and delayed nephrogram seen on a diabetic child, authors come back to the different etiologies. Among them, the tubular precipitation of Tamm-Horsfall protein seems to be given like on the right possibilities. Whatever is its etiology, the mechanism of striated appearance is always the same, being founded on the radiated disposal of the collecting ducts and on a tubular stasis beeing with iodine concentration.

  20. Theoretical Delay Time Distributions

    CERN Document Server

    Nelemans, Gijs; Bours, Madelon

    2012-01-01

    We briefly discuss the method of population synthesis to calculate theoretical delay time distributions of type Ia supernova progenitors. We also compare the results of the different research groups and conclude that although one of the main differences in the results for single degenerate progenitors is the retention efficiency with which accreted hydrogen is added to the white dwarf core, this cannot explain all the differences.

  1. Theoretical Delay Time Distributions

    Science.gov (United States)

    Nelemans, Gijs; Toonen, Silvia; Bours, Madelon

    2013-01-01

    We briefly discuss the method of population synthesis to calculate theoretical delay time distributions of Type Ia supernova progenitors. We also compare the results of different research groups and conclude that, although one of the main differences in the results for single degenerate progenitors is the retention efficiency with which accreted hydrogen is added to the white dwarf core, this alone cannot explain all the differences.

  2. Geometric Time Delay Interferometry

    OpenAIRE

    Vallisneri, Michele

    2005-01-01

    The space-based gravitational-wave observatory LISA, a NASA-ESA mission to be launched after 2012, will achieve its optimal sensitivity using Time Delay Interferometry (TDI), a LISA-specific technique needed to cancel the otherwise overwhelming laser noise in the inter-spacecraft phase measurements. The TDI observables of the Michelson and Sagnac types have been interpreted physically as the virtual measurements of a synthesized interferometer. In this paper, I present Geometric TDI, a new an...

  3. Time-Delay Interferometry

    OpenAIRE

    Dhurandhar Sanjeev V.; Tinto Massimo

    2005-01-01

    Equal-arm interferometric detectors of gravitational radiation allow phase measurements many orders of magnitude below the intrinsic phase stability of the laser injecting light into their arms. This is because the noise in the laser light is common to both arms, experiencing exactly the same delay, and thus cancels when it is differenced at the photo detector. In this situation, much lower level secondary noises then set overall performance. If, however, the two arms have different lengths (...

  4. Exploration of the Reasons for Delays in Construction

    DEFF Research Database (Denmark)

    Lindhard, Søren Munch; Wandahl, Søren

    2014-01-01

    : connecting work, change in work plans, workforce, external conditions, material and construction design. Furthermore, the study revealed five seldom-occurring causes to delay: space, equipment, rework, unexpected conditions, and safety. The findings have been structured in accordance to the preconditions......Construction sites are dominated by chaos and complexity, enforcing challenging conditions for establishing reliable and robust schedules that are easy to observe. The consequence is a large amount of delayed activities that again results in an unreliable schedule. Last planner system (LPS......) was introduced as a production planning and control system to increase the reliability of scheduling task. By focusing on the removal of constraints, the LPS has successfully decreased the number of delayed activities. To further decrease delays, this research investigates the causes for delays at three...

  5. Delay in atomic photoionization

    CERN Document Server

    Kheifets, A S

    2010-01-01

    We analyze the time delay between emission of photoelectrons from the outer valence $ns$ and $np$ sub-shells in noble gas atoms following absorption of an attosecond XUV pulse. By solving the time dependent Schr\\"odinger equation and carefully examining the time evolution of the photoelectron wave packet, we establish the apparent "time zero" when the photoelectron leaves the atom. Various processes such as elastic scattering of the photoelectron on the parent ion and many-electron correlation affect the quantum phase of the dipole transition matrix element, the energy dependence of which defines the emission timing. This qualitatively explains the time delay between photoemission from the $2s$ and $2p$ sub-shells of Ne as determined experimentally by attosecond streaking [{\\em Science} {\\bf 328}, 1658 (2010)]. However, with our extensive numerical modeling, we were only able to account for less than a half of the measured time delay of $21\\pm5$~as. We argue that the XUV pulse alone cannot produce such a larg...

  6. Time-Delay Interferometry

    Directory of Open Access Journals (Sweden)

    Massimo Tinto

    2014-08-01

    Full Text Available Equal-arm detectors of gravitational radiation allow phase measurements many orders of magnitude below the intrinsic phase stability of the laser injecting light into their arms. This is because the noise in the laser light is common to both arms, experiencing exactly the same delay, and thus cancels when it is differenced at the photo detector. In this situation, much lower level secondary noises then set the overall performance. If, however, the two arms have different lengths (as will necessarily be the case with space-borne interferometers, the laser noise experiences different delays in the two arms and will hence not directly cancel at the detector. In order to solve this problem, a technique involving heterodyne interferometry with unequal arm lengths and independent phase-difference readouts has been proposed. It relies on properly time-shifting and linearly combining independent Doppler measurements, and for this reason it has been called time-delay interferometry (TDI. This article provides an overview of the theory, mathematical foundations, and experimental aspects associated with the implementation of TDI. Although emphasis on the application of TDI to the Laser Interferometer Space Antenna (LISA mission appears throughout this article, TDI can be incorporated into the design of any future space-based mission aiming to search for gravitational waves via interferometric measurements. We have purposely left out all theoretical aspects that data analysts will need to account for when analyzing the TDI data combinations.

  7. Delayed Speech or Language Development

    Science.gov (United States)

    ... to 2-Year-Old Delayed Speech or Language Development KidsHealth > For Parents > Delayed Speech or Language Development ... child is right on schedule. Normal Speech & Language Development It's important to discuss early speech and language ...

  8. STUDY ON AN SIS EPIDEMIC MODEL WITH TIME VARIANT DELAY

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In this paper,we study an SIS epidemic model with a time variant delay.By means of Liapunov functional,some sufficient conditions of global stability to endemic equilibrium and disease free equilibrium have been obtained.The influence of time delay on the stability of equilibria is displayed.

  9. STUDY ON AN SIS EPIDEMIC MODEL WITH TIME VARIANT DELAY

    Institute of Scientific and Technical Information of China (English)

    YUAN Sanling; MA Zhien

    2002-01-01

    In this paper, we study an SIS epidemic model with a time variant delay.By means of Liapunov functional, some sufficient conditions of global stability to endemic equilibrium and disease free equilibrium have been obtained. The influence of time delay on the stability of equilibria is displayed.

  10. Asymptotic stability and stabilizability of nonlinear systems with delay.

    Science.gov (United States)

    Srinivasan, V; Sukavanam, N

    2016-11-01

    This paper is concerned with asymptotic stability and stabilizability of a class of nonlinear dynamical systems with fixed delay in state variable. New sufficient conditions are established in terms of the system parameters such as the eigenvalues of the linear operator, delay parameter, and bounds on the nonlinear parts. Finally, examples are given to testify the effectiveness of the proposed theory.

  11. Exponential passivity of neural networks with time-varying delay and uncertainty

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Song, E-mail: zhusonghust@smail.hust.edu.c [Department of Control Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Shen Yi, E-mail: yishen64@163.co [Department of Control Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Chen Guici, E-mail: gcichen@yahoo.com.c [Department of Control Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); College of Science, Wuhan University of Science and Technology, Wuhan 430081 (China)

    2010-12-01

    In this Letter, delay-dependent exponential passivity condition for delayed neural networks is obtained. Then, the result is extended to two types of uncertainties. Two numerical examples are given to demonstrate the effectiveness of the proposed criteria.

  12. Effects of time delays on bifurcation and chaos in a non-autonomous system with multiple time delays

    Energy Technology Data Exchange (ETDEWEB)

    Sun Zhongkui [Department of Applied Mathematics, Northwestern Polytechnical University, Xi' an 710072 (China)]. E-mail: sunzk205@mail.nwpu.edu.cn; Xu Wei [Department of Applied Mathematics, Northwestern Polytechnical University, Xi' an 710072 (China)]. E-mail: weixu@nwpu.edu.cn; Yang Xiaoli [Department of Applied Mathematics, Northwestern Polytechnical University, Xi' an 710072 (China); College of Mathematics and Information Science, Shaanxi Normal University, Xi' an 710062 (China); Fang Tong [Department of Applied Mechanics, Northwestern Polytechnical University, Xi' an 710072 (China)

    2007-01-15

    Time delays are often sources of complex behavior in dynamic systems. Yet its complexity needs to be further explored, particularly when multiple time delays are present. As a purpose to gain insight into such complexity under multiple time delays, we investigate the mechanism for the action of multiple time delays on a particular non-autonomous system in this paper. The original mathematical model under consideration is a Duffing oscillator with harmonic excitation. A delayed system is obtained by adding delayed feedbacks to the original system. Two time delays are involved in such system, one of which in the displacement feedback and the other in the velocity feedback. The time delays are taken as adjustable parameters to study their effects on the dynamics of the system. Firstly, the stability of the trivial equilibrium of the linearized system is discussed and the condition under which the equilibrium loses its stability is obtained. This leads to a critical stability boundary where Hopf bifurcation or double Hopf bifurcation may occur. Then, the chaotic behavior of such system is investigated in detail. Particular emphasis is laid on the effect of delay difference between two time delays on the chaotic properties. A Melnikov's analysis is employed to obtain the necessary condition for onset of chaos resulting from homoclinic bifurcation. And numerical analyses via the bifurcation diagram and the top Lyapunov exponent are carried out to show the actual time delay effect. Both the results obtained by the two analyses show that the delay difference between two time delays plays a very important role in inducing or suppressing chaos, so that it can be taken as a simple but efficient 'switch' to control the motion of a system: either from order to chaos or from chaos to order.

  13. Impulsive control of nonlinear systems with time-varying delays

    Institute of Scientific and Technical Information of China (English)

    Yu Yong-Bin; Bao Jing-Fu; Zhang Hong-Bin; Zhong Qi-Shui; Liao Xiao-Feng; Yu Jue-Sang

    2008-01-01

    A whole impulsive control scheme of nonlinear systems with time-varying delays, which is an extension for impulsive control of nonlinear systems without time delay, is presented in this paper. Utilizing the Lyapunov functions and the impulsive-type comparison principles, we establish a series of different conditions under which impulsively controlled nonlinear systems with time-varying delays are asymptotically stable. Then we estimate upper bounds of impulse interval and time-varying delays for asymptotically stable control. Finally a numerical example is given to illustrate the effectiveness of the method.

  14. Global Asymplotic Stability of Neural Networks with Time Delay

    Institute of Scientific and Technical Information of China (English)

    肖晓丹; 张洁

    2008-01-01

    The global asymptotic stability problem of Cellular neural networks with delay is investigated.A new stability condition is presented based on Lyapunov-Krasovskii method,which is dependent On the size of delay.The result is given in the form of LMI.and the admitted upper bound of the delay can be obtained easily.The time delay dependent and independent results can be obtained,which include some results in the former literature.Finally,a numerical example is siven to illustrate the effectiveness of the main results.

  15. Simultaneous quadratic performance stabilization for linear time-delay systems

    Institute of Scientific and Technical Information of China (English)

    Chen Yuepeng; Zhou Zude; Liu Huanbin; Zhang Qingling

    2006-01-01

    A newly designed approach of simultaneous stabilization is given for linear discrete time-delay systems. The problem of stabilization for a collection of systems is discussed initially. Adequate condition are obtained in terms of linear matrix inequalities (LMIs) which are independent of time delays such that the resultant collection of discrete time-delay systems are stable with an upper bound of the quadratic performance index. Subsequently, controllers are designed such that the resultant closed-loop discrete time-delay systems are simultaneously stabilized with the upper bound of the quadratic performance index. Finally,a numerical example is given to illustrate the design method.

  16. Delay Choice vs. Delay Maintenance: Different Measures of Delayed Gratification in Capuchin Monkeys (Cebus apella)

    Science.gov (United States)

    Addessi, Elsa; Paglieri, Fabio; Beran, Michael J.; Evans, Theodore A.; Macchitella, Luigi; De Petrillo, Francesca; Focaroli, Valentina

    2013-01-01

    Delaying gratification involves two components: (i) delay choice (selecting a delayed reward over an immediate one), and (ii) delay maintenance (sustaining the decision to delay gratification even if the immediate reward is available during the delay). In primates, two tasks most commonly have explored these components, the Intertemporal choice task and the Accumulation task. It is unclear whether these tasks provide equivalent measures of delay of gratification. Here, we compared the performance of the same capuchin monkeys, belonging to two study populations, between these tasks. We found only limited evidence of a significant correlation in performance. Consequently, in contrast to what is often assumed, our data provide only partial support to the hypothesis that these tasks provide equivalent measures of delay of gratification. PMID:23544770

  17. Novel Register Sharing in Datapath for Structural Robustness against Delay Variation

    OpenAIRE

    Inoue, Keisuke; KANEKO, Mineo; Iwagaki, Tsuyoshi

    2008-01-01

    As the feature size of VLSI becomes smaller, delay variations become a serious problem in VLSI. In this paper, we propose a novel class of robustness for a datapath against delay variations, which is named structural robustness against delay variation (SRV), and propose sufficient conditions for a datapath to have SRV. A resultant circuit designed under these conditions has a larger timing margin to delay variations than previous designs without sacrificing effective computation time. In addi...

  18. Adaptive control for a class of discrete-time time-delay systems with regard to delay parameter

    Institute of Scientific and Technical Information of China (English)

    Chai Lin; Cheng Ming; Fei Shumin; Zhai Junyong

    2009-01-01

    The memory state feedback control problem for a class of discrete-time systems with input delay and unknown state delay is addressed based on LMIs and Lyapunov-Krasovskii functional method. Under the action of our designed adaptive control law, the unknown time-delay parameter is included in memory state feedback controller. Using LMI technique, delay-dependent sufficient conditions for the existence of the feedback controller are obtained. Finally, the effectiveness of the proposed design method is demonstrated by a numerical example.

  19. Delaying information search

    Directory of Open Access Journals (Sweden)

    Yaniv Shani

    2012-11-01

    Full Text Available In three studies, we examined factors that may temporarily attenuate information search. People are generally curious and dislike uncertainty, which typically encourages them to look for relevant information. Despite these strong forces that promote information search, people sometimes deliberately delay obtaining valuable information. We find they may do so when they are concerned that the information might interfere with future pleasurable activities. Interestingly, the decision to search or to postpone searching for information is influenced not only by the value and importance of the information itself but also by well-being maintenance goals related to possible detrimental effects that negative knowledge may have on unrelated future plans.

  20. New Results on Passivity Analysis of Stochastic Neural Networks with Time-Varying Delay and Leakage Delay

    Directory of Open Access Journals (Sweden)

    YaJun Li

    2015-01-01

    Full Text Available The passivity problem for a class of stochastic neural networks systems (SNNs with varying delay and leakage delay has been further studied in this paper. By constructing a more effective Lyapunov functional, employing the free-weighting matrix approach, and combining with integral inequality technic and stochastic analysis theory, the delay-dependent conditions have been proposed such that SNNs are asymptotically stable with guaranteed performance. The time-varying delay is divided into several subintervals and two adjustable parameters are introduced; more information about time delay is utilised and less conservative results have been obtained. Examples are provided to illustrate the less conservatism of the proposed method and simulations are given to show the impact of leakage delay on stability of SNNs.

  1. Atmospheric Refractive Electromagnetic Wave Bending and Propagation Delay

    CERN Document Server

    Mangum, Jeffrey G

    2014-01-01

    In this tutorial we summarize the physics and mathematics behind refractive electromagnetic wave bending and delay. Refractive bending and delay through the Earth's atmosphere at both radio/millimetric and optical/IR wavelengths are discussed, but with most emphasis on the former, and with Atacama Large Millimeter Array (ALMA) applications in mind. As modern astronomical measurements often require sub-arcsecond position accuracy, care is required when selecting refractive bending and delay algorithms. For the spherically-uniform model atmospheres generally used for all refractive bending and delay algorithms, positional accuracies $\\lesssim 1^{\\prime\\prime}$ are achievable when observing at zenith angles $\\lesssim 75^\\circ$. A number of computationally economical approximate methods for atmospheric refractive bending and delay calculation are presented, appropriate for astronomical observations under these conditions. For observations under more realistic atmospheric conditions, for zenith angles $\\gtrsim 75^...

  2. CONTROLLABILITY OF DELAY DEGENERATE CONTROL SYSTEMS WITH INDEPENDENT SUBSYSTEMS

    Institute of Scientific and Technical Information of China (English)

    蒋威

    2003-01-01

    The controllability of delay degenerate differential control systems is discussed. Firstly, delay degenerate differential control system was transformed to be canonical form, and the connected terms were gotten rid of, had delay degenerate differential control systems with independent subsystems. For the general delay degenerate differnetial control systems, it was gotten that the necessary and sufficient condition of that they are controllable is that their reachable set is equal to the whole space For the delay degenerate differential control systems with independent subsystems, it was gotten that the necessary and sufficient conditions of that they are controllable are that their reachable sets are equal to their corresponding subspaces. Then some algebra criteria were gotten. Finally, an example was given to illustrate the main results.

  3. Passivity analysis and synthesis for uncertain time-delay systems

    Directory of Open Access Journals (Sweden)

    Magdi S. Mahmoud

    2001-01-01

    Full Text Available In this paper, we investigate the robust passivity analysis and synthesis problems for a class of uncertain time-delay systems. This class of systems arises in the modelling effort of studying water quality constituents in fresh stream. For the analysis problem, we derive a sufficient condition for which the uncertain time-delay system is robustly stable and strictly passive for all admissible uncertainties. The condition is given in terms of a linear matrix inequality. Both the delay-independent and delay-dependent cases are considered. For the synthesis problem, we propose an observer-based design method which guarantees that the closed-loop uncertain time-delay system is stable and strictly passive for all admissible uncertainties. Several examples are worked out to illustrate the developed theory.

  4. Epidemiology of delayed ejaculation.

    Science.gov (United States)

    Di Sante, Stefania; Mollaioli, Daniele; Gravina, Giovanni Luca; Ciocca, Giacomo; Limoncin, Erika; Carosa, Eleonora; Lenzi, Andrea; Jannini, Emmanuele A

    2016-08-01

    A large body of literature on diminished ejaculatory disorders has been generated without the use of a clear diagnostic definition. Many studies have not distinguished between the orgasm and ejaculation disorders leading to doubtful results. Delayed ejaculation (DE) is one of the diminished ejaculatory disorders, which range from varying delays in ejaculatory latency to a complete inability to ejaculate. The present review is aimed at providing a comprehensive overview of the current knowledge on the definition and epidemiology of diminished ejaculatory disorders. We focus on the acquired diseases, such as benign prostatic hyperplasia (BPH) and specific drug regimens that may cause an iatrogenic form of ejaculatory disorder. In addition, the impact of aging is discussed since the prevalence of DE appears to be moderately but positively related to age. Finally, we also focus on the importance of the hormonal milieu on male ejaculation. To date, evidence on the endocrine control of ejaculation is derived from small clinical trials, but the evidence suggests that hormones modulate the ejaculatory process by altering its overall latency.

  5. OSCILLATION OF NONLINEAR IMPULSIVE PARABOLIC DIFFERENTIAL EQUATIONS WITH SEVERAL DELAYS

    Institute of Scientific and Technical Information of China (English)

    CuiChenpei; ZouMin; LiuAnping; XiaoLi

    2005-01-01

    In this paper, oscillatory properties for solutions of certain nonlinear impulsive parabolic equations with several delays are investigated and a series of new sufficient conditions for oscillations of the equation are established.

  6. OSCILLATION OF IMPULSIVE HYPERBOLIC PARTIAL DIFFERENTIAL EQUATION WITH DELAY

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In this paper, oscillation properties of the solutions of impulsive hyperbolic equation with delay are investigated via the method of differential inequalities. Sufficient conditions for oscillations of the solutions are established.

  7. GLOBAL ATTRACTIVITY IN A PERIODIC DELAY SINGLE SPECIES MODEL

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper, we establish the existence of a positive periodic solution for a periodic delay single species population growth model, and obtain sufficient conditions for the periodic solution to be globally attractive.

  8. Expression of the immediate-early gene-encoded protein Egr-1 (zif268) during in vitro classical conditioning.

    Science.gov (United States)

    Mokin, Maxim; Keifer, Joyce

    2005-01-01

    Expression of the immediate-early genes (IEGs) has been shown to be induced by activity-dependent synaptic plasticity or behavioral training and is thought to play an important role in long-term memory. In the present study, we examined the induction and expression of the IEG-encoded protein Egr-1 during an in vitro neural correlate of eyeblink classical conditioning. The results showed that Egr-1 protein expression as determined by immunocytochemistry and Western blot analysis rapidly increased during the early stages of conditioning and remained elevated during the later stages. Further, expression of Egr-1 protein required NMDA receptor activation as it was blocked by bath application of AP-5. These findings suggest that the IEG-encoded proteins such as Egr-1 are activated during relatively simple forms of learning in vertebrates. In this case, Egr-1 may have a functional role in the acquisition phase of conditioning as well as in maintaining expression of conditioned responses.

  9. Bioequivalence of two lansoprazole delayed release capsules 30 mg in healthy male volunteers under fasting, fed and fasting-applesauce conditions: a partial replicate crossover study design to estimate the pharmacokinetics of highly variable drugs.

    Science.gov (United States)

    Thota, S; Khan, S M; Tippabhotla, S K; Battula, R; Gadiko, C; Vobalaboina, V

    2013-11-01

    An open-label, 2-treatment, 3-sequence, 3-period, single-dose, partial replicate crossover studies under fasting (n=48), fed (n=60) and fasting-applesauce (n=48) (sprinkled on one table spoonful of applesauce) modalities were conducted in healthy adult male volunteers to evaluate bioequivalence between 2 formulations of lansoprazole delayed release capsules 30 mg. In all the 3 studies, as per randomization, either test or reference formulations were administered in a crossover manner with a required washout period of at least 7 days. Blood samples were collected adequately (0-24 h) to determine lansoprazole plasma concentrations using a validated LC-MS/MS analytical method. To characterize the pharmacokinetic parameters (Cmax, AUC0-t, AUC0-∞, Tmax, Kel and T1/2) of lansoprazole, non-compartmental analysis and ANOVA was applied on ln-transformed values. The bioequivalence was tested based on within-subject variability of the reference formulation. In fasting and fed studies (within-subject variability>30%) bioequivalence was evaluated with scaled average bioequivalence, hence for the pharmacokinetic parameters Cmax, AUC0-t and AUC0-∞, the 95% upper confidence bound for (μT-μR)2-θσ2 WR was ≤0, and the point estimates (test-to-reference ratio) were within the regulatory acceptance limit 80.00-125.00%. In fasting-applesauce study (within-subject variability<30%) bioequivalence was evaluated with average bioequivalence, the 90% CI of ln-transformed data of Cmax, AUC0-t and AUC0-∞ were within the regulatory acceptance limit 80.00-125.00%. Based on these aforesaid statistical inferences, it was concluded that the test formulation is bioequivalent to reference formulation.

  10. Improved Stabilization Criteria for Neutral Time-Delay Systems

    OpenAIRE

    Lianglin Xiong; Haiyang Zhang; Yongkun Li; Zixin Liu

    2016-01-01

    This paper addresses the stabilization conditions for neutral systems with mixed time delays. By constructing a novel class of Lyapunov functionals which contains an augmented Lyapunov functional, using a new class of improved Jensen’s like inequalities, two improved delay-dependent stability criteria are firstly established. Next, state feedback controllers are designed according to the stability conditions in different cases. Finally, five numerical examples are provided to demonstrate the ...

  11. Stability and delay sensitivity of neutral fractional-delay systems

    Science.gov (United States)

    Xu, Qi; Shi, Min; Wang, Zaihua

    2016-08-01

    This paper generalizes the stability test method via integral estimation for integer-order neutral time-delay systems to neutral fractional-delay systems. The key step in stability test is the calculation of the number of unstable characteristic roots that is described by a definite integral over an interval from zero to a sufficient large upper limit. Algorithms for correctly estimating the upper limits of the integral are given in two concise ways, parameter dependent or independent. A special feature of the proposed method is that it judges the stability of fractional-delay systems simply by using rough integral estimation. Meanwhile, the paper shows that for some neutral fractional-delay systems, the stability is extremely sensitive to the change of time delays. Examples are given for demonstrating the proposed method as well as the delay sensitivity.

  12. Delay-Dependent Absolute Stability ofUncertain Lur′e Systems with Time-Delays1)

    Institute of Scientific and Technical Information of China (English)

    CHENWu-Hua; GUANZhi-Hong; LUXiao-Mei; YANGXuan-Fang

    2004-01-01

    This paper is concerned with delay dependent absolute stability for a class of uncertain Lur′e systems with multiple time-delays. By using a descriptor model transformation of the sys-tem and by applying a recent result on bounding of cross products of vectors, a new type of Lya-punov-Krasovskii functional is constructed. Based on the new functional, delay-dependent suffi-cient conditions for absolute stability are derived in terms of linear matrix inequalities. These con-ditions do not require any parameter tuning, and can be solved numerically using the software LMI Lab. A numerical example is presented which shows that the proposed method can substantiallyimprove the delay bound for absolute stability of Lur′e system with time-delays, compared to theexisting ones.

  13. Integro-differential inequality and stability of BAM FCNNs with time delays in the leakage terms and distributed delays

    Directory of Open Access Journals (Sweden)

    Zhang Xinhua

    2011-01-01

    Full Text Available Abstract In this paper, a class of impulsive bidirectional associative memory (BAM fuzzy cellular neural networks (FCNNs with time delays in the leakage terms and distributed delays is formulated and investigated. By establishing an integro-differential inequality with impulsive initial conditions and employing M-matrix theory, some sufficient conditions ensuring the existence, uniqueness and global exponential stability of equilibrium point for impulsive BAM FCNNs with time delays in the leakage terms and distributed delays are obtained. In particular, the estimate of the exponential convergence rate is also provided, which depends on the delay kernel functions and system parameters. It is believed that these results are significant and useful for the design and applications of BAM FCNNs. An example is given to show the effectiveness of the results obtained here.

  14. On the Critical Case in Oscillation for Differential Equations with a Single Delay and with Several Delays

    Directory of Open Access Journals (Sweden)

    Jaromír Baštinec

    2010-01-01

    without the usual assumption that the parameters ,ℎ,, and ℎ of the equations are continuous functions. These conditions improve and extend some known oscillation results in the critical case for delay differential equations.

  15. Delay-independent stability of genetic regulatory networks.

    Science.gov (United States)

    Wu, Fang-Xiang

    2011-11-01

    Genetic regulatory networks can be described by nonlinear differential equations with time delays. In this paper, we study both locally and globally delay-independent stability of genetic regulatory networks, taking messenger ribonucleic acid alternative splicing into consideration. Based on nonnegative matrix theory, we first develop necessary and sufficient conditions for locally delay-independent stability of genetic regulatory networks with multiple time delays. Compared to the previous results, these conditions are easy to verify. Then we develop sufficient conditions for global delay-independent stability for genetic regulatory networks. Compared to the previous results, this sufficient condition is less conservative. To illustrate theorems developed in this paper, we analyze delay-independent stability of two genetic regulatory networks: a real-life repressilatory network with three genes and three proteins, and a synthetic gene regulatory network with five genes and seven proteins. The simulation results show that the theorems developed in this paper can effectively determine the delay-independent stability of genetic regulatory networks.

  16. Synchronizing time delay systems using variable delay in coupling

    Energy Technology Data Exchange (ETDEWEB)

    Ambika, G., E-mail: g.ambika@iiserpune.ac.in [Indian Institute of Science Education and Research, Pune 411 021 (India); Amritkar, R.E., E-mail: amritkar@prl.res.in [Physical Research Laboratory, Ahmedabad 380 009 (India)

    2011-11-15

    Highlights: > Delay and anticipation in coupling function varies with system dynamics. > Delay or anticipation of the synchronized state is independent of system delay. > Stability analysis developed is quite general. > We demonstrate enhanced security in communication. > Generalized synchronization possible over a wide range of parameter mismatch. - Abstract: We present a mechanism for synchronizing time delay systems using one way coupling with a variable delay in coupling that is reset at finite intervals. We present the analysis of the error dynamics that helps to isolate regions of stability of the synchronized state in the parameter space of interest for single and multiple delays. We supplement this by numerical simulations in a standard time delay system like Mackey Glass system. This method has the advantage that it can be adjusted to be delay or anticipatory in synchronization with a time which is independent of the system delay. We demonstrate the use of this method in communication using the bi channel scheme. We show that since the synchronizing channel carries information from transmitter only at intervals of reset time, it is not susceptible to an easy reconstruction.

  17. Delay tolerant networks

    CERN Document Server

    Gao, Longxiang; Luan, Tom H

    2015-01-01

    This brief presents emerging and promising communication methods for network reliability via delay tolerant networks (DTNs). Different from traditional networks, DTNs possess unique features, such as long latency and unstable network topology. As a result, DTNs can be widely applied to critical applications, such as space communications, disaster rescue, and battlefield communications. The brief provides a complete investigation of DTNs and their current applications, from an overview to the latest development in the area. The core issue of data forward in DTNs is tackled, including the importance of social characteristics, which is an essential feature if the mobile devices are used for human communication. Security and privacy issues in DTNs are discussed, and future work is also discussed.

  18. Delay-dependent H2 control for discrete time-delay systems with D-stability constraints

    Institute of Scientific and Technical Information of China (English)

    Man Sun; Yingmin Jia; Junping Du; Shiying Yuan

    2008-01-01

    This paper studies the problem of H2 control for a class of discrete time-delay systems with D-stability constraints. The corresponding sufficient conditions are given in terms of linear matrix inequalities. In particular, the conditions are delay-dependent, and so they are less conservative. The obtained controller can provide an upper bound for the H2 cost function. A numerical example is given to illustrate the proposed method.

  19. Delay-dependent asymptotic stability for neural networks with time-varying delays

    Directory of Open Access Journals (Sweden)

    Xiaofeng Liao

    2006-01-01

    ensure local and global asymptotic stability of the equilibrium of the neural network. Our results are applied to a two-neuron system with delayed connections between neurons, and some novel asymptotic stability criteria are also derived. The obtained conditions are shown to be less conservative and restrictive than those reported in the known literature. Some numerical examples are included to demonstrate our results.

  20. Chaos synchronization by resonance of multiple delay times

    Science.gov (United States)

    Martin, Manuel Jimenez; D'Huys, Otti; Lauerbach, Laura; Korutcheva, Elka; Kinzel, Wolfgang

    2016-02-01

    Chaos synchronization may arise in networks of nonlinear units with delayed couplings. We study complete and sublattice synchronization generated by resonance of two large time delays with a specific ratio. As it is known for single-delay networks, the number of synchronized sublattices is determined by the greatest common divisor (GCD) of the network loop lengths. We demonstrate analytically the GCD condition in networks of iterated Bernoulli maps with multiple delay times and complement our analytic results by numerical phase diagrams, providing parameter regions showing complete and sublattice synchronization by resonance for Tent and Bernoulli maps. We compare networks with the same GCD with single and multiple delays, and we investigate the sensitivity of the correlation to a detuning between the delays in a network of coupled Stuart-Landau oscillators. Moreover, the GCD condition also allows detection of time-delay resonances, leading to high correlations in nonsynchronizable networks. Specifically, GCD-induced resonances are observed both in a chaotic asymmetric network and in doubly connected rings of delay-coupled noisy linear oscillators.

  1. dependent time-delay: Stability and stabilizability

    Directory of Open Access Journals (Sweden)

    E. K. Boukas

    2002-01-01

    Full Text Available This paper considers stochastic stability and stochastic stabilizability of linear discrete-time systems with Markovian jumps and mode-dependent time-delays. Linear matrix inequality (LMI techniques are used to obtain sufficient conditions for the stochastic stability and stochastic stabilizability of this class of systems. A control design algorithm is also provided. A numerical example is given to demonstrate the effectiveness of the obtained theoretical results.

  2. On the Gravitomagnetic Time Delay

    OpenAIRE

    Ciufolini, I.; Kopeikin, S.; Mashhoon, B.; Ricci, F

    2002-01-01

    We study the gravitational time delay in ray propagation due to rotating masses in the linear approximation of general relativity. Simple expressions are given for the gravitomagnetic time delay that occurs when rays of radiation cross a slowly rotating shell and propagate in the field of a distant rotating source. Moreover, we calculate the local gravitational time delay in the Goedel universe. The observational consequences of these results in the case of weak gravitational lensing are disc...

  3. Demographic determinants of delayed divorce.

    Science.gov (United States)

    Chan, L Y; Heaton, T B

    1989-01-01

    This study identifies factors that predict delayed divorce in the US. The findings show that factors which influence marital stability in general also correlate with delayed divorce in the same direction. Wife's age at marriage, age of the youngest child, wife's religion, region of residence, and metropolitan residence have substantial effects of delayed divorce, but the effects of race, parental divorce, premarital pregnancy, and socioeconomic status are small.

  4. Location Estimation using Delayed Measurements

    DEFF Research Database (Denmark)

    Bak, Martin; Larsen, Thomas Dall; Nørgård, Peter Magnus

    1998-01-01

    When combining data from various sensors it is vital to acknowledge possible measurement delays. Furthermore, the sensor fusion algorithm, often a Kalman filter, should be modified in order to handle the delay. The paper examines different possibilities for handling delays and applies a new techn...... technique to a sensor fusion system for estimating the location of an autonomous guided vehicle. The system fuses encoder and vision measurements in an extended Kalman filter. Results from experiments in a real environment are reported...

  5. Concurrent Delay in Construction Disputes

    DEFF Research Database (Denmark)

    Cavaleri, Sylvie Cécile

    period of delay can potentially be attributed to several events falling within both parties' spheres of responsibility, commonly termed concurrent delay, is rarely regulated in construction contracts in spite of its common occurrence. This book analyses both the theoretical foundations and the practical......Delay is one of the issues most frequently encountered in today’s construction industry; it causes significant economic damage to all parties involved. Construction contracts, standard and bespoke, almost invariably consider delay from a perspective of single liability. If the event causing...

  6. Time Delay of CGM Sensors

    Science.gov (United States)

    Schmelzeisen-Redeker, Günther; Schoemaker, Michael; Kirchsteiger, Harald; Freckmann, Guido; Heinemann, Lutz; del Re, Luigi

    2015-01-01

    Background: Continuous glucose monitoring (CGM) is a powerful tool to support the optimization of glucose control of patients with diabetes. However, CGM systems measure glucose in interstitial fluid but not in blood. Rapid changes in one compartment are not accompanied by similar changes in the other, but follow with some delay. Such time delays hamper detection of, for example, hypoglycemic events. Our aim is to discuss the causes and extent of time delays and approaches to compensate for these. Methods: CGM data were obtained in a clinical study with 37 patients with a prototype glucose sensor. The study was divided into 5 phases over 2 years. In all, 8 patients participated in 2 phases separated by 8 months. A total number of 108 CGM data sets including raw signals were used for data analysis and were processed by statistical methods to obtain estimates of the time delay. Results: Overall mean (SD) time delay of the raw signals with respect to blood glucose was 9.5 (3.7) min, median was 9 min (interquartile range 4 min). Analysis of time delays observed in the same patients separated by 8 months suggests a patient dependent delay. No significant correlation was observed between delay and anamnestic or anthropometric data. The use of a prediction algorithm reduced the delay by 4 minutes on average. Conclusions: Prediction algorithms should be used to provide real-time CGM readings more consistent with simultaneous measurements by SMBG. Patient specificity may play an important role in improving prediction quality. PMID:26243773

  7. Concurrent Delay in Construction Disputes

    DEFF Research Database (Denmark)

    Cavaleri, Sylvie Cécile

    Delay is one of the issues most frequently encountered in today’s construction industry; it causes significant economic damage to all parties involved. Construction contracts, standard and bespoke, almost invariably consider delay from a perspective of single liability. If the event causing...... period of delay can potentially be attributed to several events falling within both parties' spheres of responsibility, commonly termed concurrent delay, is rarely regulated in construction contracts in spite of its common occurrence. This book analyses both the theoretical foundations and the practical...

  8. Characterizing cognitive aging of associative memory in animal models.

    Science.gov (United States)

    Engle, James R; Barnes, Carol A

    2012-01-01

    An overview is provided of the simple single-cue delay and trace eyeblink conditioning paradigms as techniques to assess associative learning and memory in the aged. We highlight and focus this review on the optimization of the parameter space of eyeblink conditioning designs in the aged to avoid and control for potential confounds that may arise when studying aged mammals. The need to examine the contribution of non-associative factors that can contribute to performance outcomes is emphasized, and how age-related changes in the central nervous system as well as peripheral sensory factors can potentially bias the interpretation of the data in the aged is discussed. The way in which slight alterations of the parameter space in the delay and trace eyeblink conditioning paradigms can lead to delayed but intact conditioning, rather than impaired performance in aged animals is also discussed. Overall, the eyeblink conditioning paradigm, when optimized for the age of the animal in the study, is an elegantly simple technique for assessment of associative learning and memory. When design caveats described above are taken into account, this important type of memory, with its well-defined neural substrates, should definitely be included in cognitive assessment batteries for the aged.

  9. Characterizing cognitive aging of associative memory in animal models

    Directory of Open Access Journals (Sweden)

    James R Engle

    2012-09-01

    Full Text Available An overview is provided of the simple single-cue delay and trace eyeblink conditioning paradigms as techniques to assess associative learning and memory in the aged. We highlight and focus this review on the optimization of the parameter space of eyeblink conditioning designs in the aged to avoid and control for potential confounds that may arise when studying aged mammals. The need to examine the contribution of non-associative factors that can contribute to performance outcomes is emphasized, and how age-related changes in the central nervous system as well as peripheral sensory factors can potentially bias the interpretation of the data in the aged is discussed. The way in which slight alterations of the parameter space in the delay and trace eyeblink conditioning paradigms can lead to delayed but intact conditioning, rather than impaired performance in aged animals is also discussed. Overall, the eyeblink conditioning paradigm, when optimized for the age of the animal in the study, is an elegantly simple technique for assessment of associative learning and memory. When design caveats described above are taken into account, this important type of memory, with its well-defined neural substrates, should definitely be included in cognitive assessment batteries for the aged.

  10. STABILITY OF N-DIMENSIONAL LINEAR SYSTEMS WITH MULTIPLE DELAYS AND APPLICATION TO SYNCHRONIZATION

    Institute of Scientific and Technical Information of China (English)

    Weihua DENG; Jinhu L(U); Changpin LI

    2006-01-01

    This paper further investigates the stability of the n-dimensional linear systems with multiple delays. Using Laplace transform, we introduce a definition of characteristic equation for the n-dimensional linear systems with multiple delays. Moreover, one sufficient condition is attained for the Lyapunov globally asymptotical stability of the general multi-delay linear systems. In particular, our result shows that some uncommensurate linear delays systems have the similar stability criterion as that of the commensurate linear delays systems. This result also generalizes that of Chen and Moore (2002). Finally, this theorem is applied to chaos synchronization of the multi-delay coupled Chua's systems.

  11. Global Stability, Bifurcation, and Chaos Control in a Delayed Neural Network Model

    Directory of Open Access Journals (Sweden)

    Amitava Kundu

    2014-01-01

    Full Text Available Conditions for the global asymptotic stability of delayed artificial neural network model of n (≥3 neurons have been derived. For bifurcation analysis with respect to delay we have considered the model with three neurons and used suitable transformation on multiple time delays to reduce it to a system with single delay. Bifurcation analysis is discussed with respect to single delay. Numerical simulations are presented to verify the analytical results. Using numerical simulation, the role of delay and neuronal gain parameter in changing the dynamics of the neural network model has been discussed.

  12. Global exponential periodicity and stability of recurrent neural networks with multi-proportional delays.

    Science.gov (United States)

    Zhou, Liqun; Zhang, Yanyan

    2016-01-01

    In this paper, a class of recurrent neural networks with multi-proportional delays is studied. The nonlinear transformation transforms a class of recurrent neural networks with multi-proportional delays into a class of recurrent neural networks with constant delays and time-varying coefficients. By constructing Lyapunov functional and establishing the delay differential inequality, several delay-dependent and delay-independent sufficient conditions are derived to ensure global exponential periodicity and stability of the system. And several examples and their simulations are given to illustrate the effectiveness of obtained results.

  13. On minimizing the maximum broadcast decoding delay for instantly decodable network coding

    KAUST Repository

    Douik, Ahmed S.

    2014-09-01

    In this paper, we consider the problem of minimizing the maximum broadcast decoding delay experienced by all the receivers of generalized instantly decodable network coding (IDNC). Unlike the sum decoding delay, the maximum decoding delay as a definition of delay for IDNC allows a more equitable distribution of the delays between the different receivers and thus a better Quality of Service (QoS). In order to solve this problem, we first derive the expressions for the probability distributions of maximum decoding delay increments. Given these expressions, we formulate the problem as a maximum weight clique problem in the IDNC graph. Although this problem is known to be NP-hard, we design a greedy algorithm to perform effective packet selection. Through extensive simulations, we compare the sum decoding delay and the max decoding delay experienced when applying the policies to minimize the sum decoding delay and our policy to reduce the max decoding delay. Simulations results show that our policy gives a good agreement among all the delay aspects in all situations and outperforms the sum decoding delay policy to effectively minimize the sum decoding delay when the channel conditions become harsher. They also show that our definition of delay significantly improve the number of served receivers when they are subject to strict delay constraints.

  14. 基于队列理论CSMA/CA机制的无线传感器异构机制OSTS的实时性分析%Delay analysis for OSTS scheme of CSMA/CA with heterogeneous unsaturated conditions

    Institute of Scientific and Technical Information of China (English)

    吕春峰; 朱建平

    2012-01-01

    自从IEEE 802.15.4标准发布以来,基于低功耗、低速率传输的无线传感器网络的应用几乎涉及到现实生活的方方面面;但是关于这个标准的CSMA/CA机制大部分都是基于均匀、饱和的传感器网络应用。文中针对非饱和、带缓存的无线传感器异构网络,提出了一种新的异构的CSMA/CA机制OSTS。该机制采用2个马尔可夫链来分别表示异构节点访问信道的过程、一个宏观马尔可夫链来表达信道状态转移,且结合M/G/1/K队列理论分析数据包传送的实时性能,并相应地改进系统的实时性。文中最大的特点是两组非均匀节点被赋予了公平的机会访问信道,而不存在优先权的问题。此外,详细分析了这种机制的数据包传送时间,包括数据包到达率、包大小、节点数量、缓存大小等参数对系统实时性的影响;这些分析结果与我们采用NS-2工具仿真的结果十分吻合。%Analyses of IEEE 802.15.4 Carrier Sense Multiple Access with Collision Avoidance(CSMA/CA) mechanism have received considerable attention recently,and most of these analyses focus on homogeneous or saturated traffic.In this paper,we propose a new CSMA/CA scheme OSTS to evaluate and improve the performance of heterogeneous buffered networks which is more realistic in our applications.We adopt two modified semi-Markov chains with one macro-Markov chain and the theory of M/G/1/K queues to evaluate characteristics of our time-critical non-priority network.Packet delay of unsaturated,unacknowledged 802.15.4 beacon enabled networks based on these models are predicted,including the impact of different parameters such as packet arrival rate,packet size,node’s buffer size and the number of different kinds of nodes.Comprehensive simulation results are consistent with the predictions of these models.

  15. Reinforcement Delay Fading during Differential Reinforcement of Communication: The Effects of Signals on Response Maintenance

    Science.gov (United States)

    Kelley, Michael E.; Lerman, Dorothea C.; Fisher, Wayne W.; Roane, Henry S.; Zangrillo, Amanda N.

    2011-01-01

    Signals during delays to reinforcement may lessen reductions in responding that typically occur when there is a delay between a response and its reinforcer. Sparse applied research has been devoted to understanding the conditions under which responding may be maintained when delays to reinforcement are introduced. We evaluated the extent to which…

  16. Delay-Amount Tradeoffs in Choices by Pigeons and Rats: Hyperbolic versus Exponential Discounting

    Science.gov (United States)

    Mazur, James E.; Biondi, Dawn R.

    2009-01-01

    An adjusting-delay procedure was used to study the choices of pigeons and rats when both delay and amount of reinforcement were varied. In different conditions, the choice alternatives included one versus two reinforcers, one versus three reinforcers, and three versus two reinforcers. The delay to one alternative (the standard alternative) was…

  17. Permanence for two-species Lotka-Volterra cooperative systems with delays.

    Science.gov (United States)

    Lu, Guichen; Lu, Zhengyi

    2008-07-01

    In this paper, a two-species Lotka-Volterra cooperative delay system is considered, and the relationships between the delays and the permanence are obtained. Some sufficient conditions for the permanence under the assumption of smallness of the delays are obtained. Two examples are given to illustrate the theorems.

  18. Delay and Its Time-Derivative Dependent Bounded Real Lemma for Linear Time-Delay Systems

    Institute of Scientific and Technical Information of China (English)

    JIANGXiefu; XUWenli

    2004-01-01

    Based on an appropriate Lyapunov-Krasovskii functional, this paper deals with the problem of the bounded real lemma for linear continuous-time systems with state delay. The system under consideration involves state time-varying time-delay. A sufficient condition for the system to possess a H∞-norm that is less than a prescribed level, is presented in a Linear matrix inequality(LMI) form which is dependent on both the size of timedelay and the size of its time-derivative. Due to that fewercross terms should be bounded, our result is less conservative. Finally, an example is presented to demonstrate the effectiveness of our result.

  19. Delay-dependent stability analysis for discrete-time systems with time varying state delay

    Directory of Open Access Journals (Sweden)

    Stojanović Sreten B.

    2011-01-01

    Full Text Available The stability of discrete systems with time-varying delay is considered. Some sufficient delaydependent stability conditions are derived using an appropriate model transformation of the original system. The criteria are presented in the form of LMI, which are dependent on the minimum and maximum delay bounds. It is shown that the stability criteria are approximately the same conservative as the existing ones, but have much simpler mathematical form. The numerical example is presented to illustrate the applicability of the developed results.

  20. Synchronization transitions in coupled time-delay electronic circuits with a threshold nonlinearity.

    Science.gov (United States)

    Srinivasan, K; Senthilkumar, D V; Murali, K; Lakshmanan, M; Kurths, J

    2011-06-01

    Experimental observations of typical kinds of synchronization transitions are reported in unidirectionally coupled time-delay electronic circuits with a threshold nonlinearity and two time delays, namely feedback delay τ(1) and coupling delay τ(2). We have observed transitions from anticipatory to lag via complete synchronization and their inverse counterparts with excitatory and inhibitory couplings, respectively, as a function of the coupling delay τ(2). The anticipating and lag times depend on the difference between the feedback and the coupling delays. A single stability condition for all the different types of synchronization is found to be valid as the stability condition is independent of both the delays. Further, the existence of different kinds of synchronizations observed experimentally is corroborated by numerical simulations and from the changes in the Lyapunov exponents of the coupled time-delay systems.

  1. Stochastic stability of linear time-delay system with Markovian jumping parameters

    Directory of Open Access Journals (Sweden)

    K. Benjelloun

    1997-01-01

    Full Text Available This paper deals with the class of linear time-delay systems with Markovian jumping parameters (LTDSMJP. We mainly extend the stability results of the deterministic class of linear systems with time-delay to this class of systems. A delay-independent necessary condition and sufficient conditions for checking the stochastic stability are established. A sufficient condition is also given. Some numerical examples are provided to show the usefulness of the proposed theoretical results.

  2. Exponential Stability of Stochastic Nonlinear Dynamical Price System with Delay

    Directory of Open Access Journals (Sweden)

    Wenli Zhu

    2013-01-01

    Full Text Available Based on Lyapunov stability theory, Itô formula, stochastic analysis, and matrix theory, we study the exponential stability of the stochastic nonlinear dynamical price system. Using Taylor's theorem, the stochastic nonlinear system with delay is reduced to an n-dimensional semilinear stochastic differential equation with delay. Some sufficient conditions of exponential stability and corollaries for such price system are established by virtue of Lyapunov function. The time delay upper limit is solved by using our theoretical results when the system is exponentially stable. Our theoretical results show that if the classical price Rayleigh equation is exponentially stable, so is its perturbed system with delay provided that both the time delay and the intensity of perturbations are small enough. Two examples are presented to illustrate our results.

  3. An SIRS Epidemic Model Incorporating Media Coverage with Time Delay

    Science.gov (United States)

    Lin, Yiping; Dai, Yunxian

    2014-01-01

    An SIRS epidemic model incorporating media coverage with time delay is proposed. The positivity and boundedness are studied firstly. The locally asymptotical stability of the disease-free equilibrium and endemic equilibrium is studied in succession. And then, the conditions on which periodic orbits bifurcate are given. Furthermore, we show that the local Hopf bifurcation implies the global Hopf bifurcation after the second critical value of the delay. The obtained results show that the time delay in media coverage can not affect the stability of the disease-free equilibrium when the basic reproduction number R0 1, the stability of the endemic equilibrium will be affected by the time delay; there will be a family of periodic orbits bifurcating from the endemic equilibrium when the time delay increases through a critical value. Finally, some examples for numerical simulations are also included. PMID:24723967

  4. On modeling the digital gate delay under process variation

    Institute of Scientific and Technical Information of China (English)

    Gao Mingzhi; Ye Zuochang; Wang Yan; Yu Zhiping

    2011-01-01

    To achieve a characterization method for the gate delay library used in block based statistical static timing analysis with neither unacceptably poor accuracy nor forbiddingly high cost,we found that general-purpose gate delay models are useful as intermediaries between the circuit simulation data and the gate delay models in required forms.In this work,two gate delay models for process variation considering different driving and loading conditions are proposed.From the testing results,these two models,especially the one that combines effective dimension reduction (EDR) from statistics society with comprehensive gate delay models,offer good accuracy with low characterization cost,and they are thus competent for use in statistical timing analysis (SSTA).In addition,these two models have their own value in other SSTA techniques.

  5. Robust filtering and fault detection of switched delay systems

    CERN Document Server

    Wang, Dong; Wang, Wei

    2013-01-01

    Switched delay systems appear in a wide field of applications including networked control systems, power systems, memristive systems. Though the large amount of ideas with respect to such systems have generated, until now, it still lacks a framework to focus on filter design and fault detection issues which are relevant to life safety and property loss. Beginning with the comprehensive coverage of the new developments in the analysis and control synthesis for switched delay systems, the monograph not only provides a systematic approach to designing the filter and detecting the fault of switched delay systems, but it also covers the model reduction issues. Specific topics covered include: (1) Arbitrary switching signal where delay-independent and delay-dependent conditions are presented by proposing a linearization technique. (2) Average dwell time where a weighted Lyapunov function is come up with dealing with filter design and fault detection issues beside taking model reduction problems. The monograph is in...

  6. Linearized oscillation theory for a nonlinear delay impulsive equation

    Science.gov (United States)

    Berezansky, Leonid; Braverman, Elena

    2003-12-01

    For a scalar nonlinear impulsive delay differential equationwith rk(t)≥0,hk(t)≤t, limj-->∞ τj=∞, such an auxiliary linear impulsive delay differential equationis constructed that oscillation (nonoscillation) of the nonlinear equation can be deduced from the corresponding properties of the linear equation. Coefficients rk(t) and delays are not assumed to be continuous. Explicit oscillation and nonoscillation conditions are established for some nonlinear impulsive models of population dynamics, such as the impulsive logistic equation and the impulsive generalized Lasota-Wazewska equation which describes the survival of red blood cells. It is noted that unlike nonimpulsive delay logistic equations a solution of a delay impulsive logistic equation may become negative.

  7. Stability of discrete Hopfield neural networks with delay

    Institute of Scientific and Technical Information of China (English)

    Ma Runnian; Lei Sheping; Liu Naigong

    2005-01-01

    Discrete Hopfield neural network with delay is an extension of discrete Hopfield neural network. As it is well known, the stability of neural networks is not only the most basic and important problem but also foundation of the network's applications. The stability of discrete Hopfield neural networks with delay is mainly investigated by using Lyapunov function. The sufficient conditions for the networks with delay converging towards a limit cycle of length 4 are obtained. Also, some sufficient criteria are given to ensure the networks having neither a stable state nor a limit cycle with length 2. The obtained results here generalize the previous results on stability of discrete Hopfield neural network with delay and without delay.

  8. Absolute stability of nonlinear systems with time delays and applications to neural networks

    Directory of Open Access Journals (Sweden)

    Xinzhi Liu

    2001-01-01

    Full Text Available In this paper, absolute stability of nonlinear systems with time delays is investigated. Sufficient conditions on absolute stability are derived by using the comparison principle and differential inequalities. These conditions are simple and easy to check. In addition, exponential stability conditions for some special cases of nonlinear delay systems are discussed. Applications of those results to cellular neural networks are presented.

  9. Registration Delay and Student Performance

    Science.gov (United States)

    Siefken, Jason

    2017-01-01

    Tracking the difference between the time a first-year student is allowed to register for a course and the time he or she does register for a course (a student's registration delay), we notice a negative correlation between registration delay and final grade in a course. The difference between a student who registers within the first two minutes…

  10. 78 FR 59422 - Delayed Applications

    Science.gov (United States)

    2013-09-26

    ... Pipeline and Hazardous Materials Safety Administration Delayed Applications AGENCY: Office of Hazardous... applications delayed more than 180 days. SUMMARY: In accordance with the requirements of 49 U.S.C. 5117(c), PHMSA is publishing the following list of special permit applications that have been in process for 180...

  11. High resolution digital delay timer

    Science.gov (United States)

    Martin, Albert D.

    1988-01-01

    Method and apparatus are provided for generating an output pulse following a trigger pulse at a time delay interval preset with a resolution which is high relative to a low resolution available from supplied clock pulses. A first lumped constant delay (20) provides a first output signal (24) at predetermined interpolation intervals corresponding to the desired high resolution time interval. Latching circuits (26, 28) latch the high resolution data (24) to form a first synchronizing data set (60). A selected time interval has been preset to internal counters (142, 146, 154) and corrected for circuit propagation delay times having the same order of magnitude as the desired high resolution. Internal system clock pulses (32, 34) count down the counters to generate an internal pulse delayed by an interval which is functionally related to the preset time interval. A second LCD (184) corrects the internal signal with the high resolution time delay. A second internal pulse is then applied to a third LCD (74) to generate a second set of synchronizing data (76) which is complementary with the first set of synchronizing data (60) for presentation to logic circuits (64). The logic circuits (64) further delay the internal output signal (72) to obtain a proper phase relationship of an output signal (80) with the internal pulses (32, 34). The final delayed output signal (80) thereafter enables the output pulse generator (82) to produce the desired output pulse (84) at the preset time delay interval following input of the trigger pulse (10, 12).

  12. Calibrating for Ionospheric Phase Delays

    Science.gov (United States)

    Macdoran, P. F.

    1985-01-01

    Technique determines ionospheric phase delay on real-time universally applicable basis in terms of electrons per meter squared by coherently modulating two L-band carrier frequencies received from two Global Positioning System satelites. Two pseudorandom number sequences cross-correlated to derive delay time.

  13. #FakeNobelDelayReasons

    CERN Multimedia

    2013-01-01

    Tuesday’s hour-long delay of the Nobel Prize in Physics announcement was (and still is) quite the cause for speculation. But on the Twittersphere, it was simply the catalyst for some fantastic puns, so-bad-they're-good physics jokes and other shenanigans. Here are some of our favourite #FakeNobelDelayReasons.    

  14. Imitation dynamics with time delay.

    Science.gov (United States)

    Wang, Shi-Chang; Yu, Jie-Ru; Kurokawa, Shun; Tao, Yi

    2017-05-07

    Based on the classic imitation dynamics (Hofbauer and Sigmund, 1998, Evolutionary Games and Population Dynamics, Cambridge University Press), the imitation dynamics with time delay is investigated, where the probability that an individual will imitate its opponent's own strategy is assumed to depend on the comparison between the past expected payoff of this individual's own strategy and the past expected payoff of its opponent's own strategy, i.e. there is a time delay effect. For the two-phenotype model, we show that if the system has an interior equilibrium and this interior equilibrium is stable when there is no time delay, then there must be a critical value of time delay such that the system tends to a stable periodic solution when the time delay is larger than the critical value. On the other hand, for three-phenotype (rock-scissors-paper) model, the numerical analysis shows that for the stable periodic solution induced by the time delay, the amplitude and the period will increase with the increase of the time delay. These results should help to understand the evolution of behavior based on the imitation dynamics with time delay. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Magnetic bearing optical delay line

    NARCIS (Netherlands)

    Dool, T.C. van den; Kamphues, F.G.; Fouss, B.; Henrioulle, K.; Hogenhuis, H.

    2004-01-01

    TNO TPD, in close cooperation with Micromega-Dynamics and Dutch Space, has developed an advanced Optical Delay Line (ODL) for use in PRIMA, GENIE and other ground based interferometers. The delay line design is modular and flexible, which makes scaling for other applications a relatively easy task.

  16. Novel Register Sharing in Datapath for Structural Robustness against Delay Variation

    Science.gov (United States)

    Inoue, Keisuke; Kaneko, Mineo; Iwagaki, Tsuyoshi

    As the feature size of VLSI becomes smaller, delay variations become a serious problem in VLSI. In this paper, we propose a novel class of robustness for a datapath against delay variations, which is named structural robustness against delay variation (SRV), and propose sufficient conditions for a datapath to have SRV. A resultant circuit designed under these conditions has a larger timing margin to delay variations than previous designs without sacrificing effective computation time. In addition, under any degree of delay variations, we can always find an available clock frequency for a datapath having SRV property to operate correctly, which could be a preferable characteristic in IP-based design.

  17. Synthesis for robust synchronization of chaotic systems under output feedback control with multiple random delays

    Energy Technology Data Exchange (ETDEWEB)

    Wen Guilin [Key Laboratory of Advanced Technology for Vehicle Body Design and Manufactory, M.O.E, College of Mechanical and Automotive Engineering, Hunan University, Changsha, Hunan 410082 (China); Wang Qingguo [Department of Electrical and Computer Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260 (Singapore)]. E-mail: elewqg@nus.edu.sg; Lin Chong [Department of Electrical and Computer Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260 (Singapore); Han Xu [Key Laboratory of Advanced Technology for Vehicle Body Design and Manufactory, M.O.E, College of Mechanical and Automotive Engineering, Hunan University, Changsha, Hunan 410082 (China); Li Guangyao [Key Laboratory of Advanced Technology for Vehicle Body Design and Manufactory, M.O.E, College of Mechanical and Automotive Engineering, Hunan University, Changsha, Hunan 410082 (China)

    2006-09-15

    Synchronization under output feedback control with multiple random time delays is studied, using the paradigm in nonlinear physics-Chua's circuit. Compared with other synchronization control methods, output feedback control with multiple random delay is superior for a realistic synchronization application to secure communications. Sufficient condition for global stability of delay-dependent synchronization is established based on the LMI technique. Numerical simulations fully support the analytical approach, in spite of the random delays.

  18. Stability Tests of Positive Fractional Continuous-time Linear Systems with Delays

    Directory of Open Access Journals (Sweden)

    Tadeusz Kaczorek

    2013-06-01

    Full Text Available Necessary and sufficient conditions for the asymptotic stability of positive fractional continuous-time linear systems with many delays are established. It is shown that: 1 the asymptotic stability of the positive fractional system is independent of their delays, 2 the checking of the asymptotic stability of the positive fractional systems with delays can be reduced to checking of the asymptotic stability of positive standard linear systems without delays.

  19. GLOBAL ASYMPTOTIC STABILITY IN N-SPECIES NONAUTONOMOUS LOTKA-VOLTERRA COMPETITIVE SYSTEMS WITH DELAYS

    Institute of Scientific and Technical Information of China (English)

    Xu Rui(徐瑞); Chen Lansun(陈兰荪); M.A.J. Chaplain

    2003-01-01

    A delayed n-species nonautonomous Lotka-Volterra type competitive systemwithout dominating instantaneous negative feedback is investigated. By means of a suitableLyapunov functional, sufficient conditions are derived for the global asymptotic stability ofthe positive solutions of the system. As a corollary, it is shown that the global asymptoticstability of the positive solution is maintained provided that the delayed negative feedbacksdominate other interspecific interaction effects with delays and the delays are sufficientlysmall.

  20. Modeling of Ionospheric Delay for SBAS Using Spherical Harmonics Functions

    Directory of Open Access Journals (Sweden)

    Deokhwa Han

    2013-06-01

    Full Text Available In SBAS (satellite-based augmentation system, it is important to estimate ionospheric delay accurately to guarantee user's accuracy and integrity. Grid based ionospheric models are generally used to estimate ionospheric delay for SBAS. In grid based model, SBAS broadcasts vertical ionospheric delays at the grid point, and users get their ionospheric delay by interpolating those values. Ionospheric model based on spherical harmonics function is another method to estimate ionospheric delay. This is a function based approach and spherical harmonics function is a 2-D fourier series, containing the product of latitude dependent associated Legendre functions and the sum of the longitude dependent sine and cosine terms. Using ionospheric delay measurements, coefficients for each spherical harmonics functions are estimated. If these coefficients are known, user can reconstruct ionospheric delay. In this paper, we consider the spherical harmonics based model and propose a ionospheric delay estimation strategy for SBAS that can be used to mitigate ionospheric delay estimation error, especially in storm condition. First, coefficients are estimated under initial order and degree. Then residual errors for each measurement are modeled by higher order and degree terms, then coefficients for these terms are estimated. Because SBAS message capacity is limited, in normal condition, initial order terms are only used to estimate ionospheric delay. If ionospheric storm is detected and there is need to mitigate the error, higher order terms are also used and error can be decreased. To compare the accuracy of spherical harmonics based model with grid based model, some post-processing test results are presented. Raw observation data is obtained from RINEX format and the root mean square(RMS and max value of residual errors are presented.

  1. Time-delay damping theory

    Institute of Scientific and Technical Information of China (English)

    洪峰

    2002-01-01

    In this paper, existing damping theories are briefly reviewed. On the basis of the existing damping theories, a new kind of damping theory, i.e., the time-delay damping theory, is developed. In the time-delay damping theory, the damping force is considered to be directly proportional to the increment of displacement. The response analysis of an SDOF time-delay damping system is carried out, and the methods for obtaining the solution for a time-delay damping system in the time domain as well as the frequency domain are given. The comparison between results from different damping theories shows that the time-delay damping theory is both reasonable and convenient.

  2. Novel delay-distribution-dependent stability analysis for continuous-time recurrent neural networks with stochastic delay

    Institute of Scientific and Technical Information of China (English)

    Wang Shen-Quan; Feng Jian; Zhao Qing

    2012-01-01

    In this paper,the problem of delay-distribution-dependent stability is investigated for continuous-time recurrent neural networks (CRNNs) with stochastic delay.Different from the common assumptions on time delays,it is assumed that the probability distribution of the delay taking values in some intervals is known a priori.By making full use of the information concerning the probability distribution of the delay and by using a tighter bounding technique (the reciprocally convex combination method),less conservative asymptotic mean-square stable sufficient conditions are derived in terms of linear matrix inequalities (LMIs).Two numerical examples show that our results are better than the existing ones.

  3. Global μ-Stability of Impulsive Complex-Valued Neural Networks with Leakage Delay and Mixed Delays

    Directory of Open Access Journals (Sweden)

    Xiaofeng Chen

    2014-01-01

    Full Text Available The impulsive complex-valued neural networks with three kinds of time delays including leakage delay, discrete delay, and distributed delay are considered. Based on the homeomorphism mapping principle of complex domain, a sufficient condition for the existence and uniqueness of the equilibrium point of the addressed complex-valued neural networks is proposed in terms of linear matrix inequality (LMI. By constructing appropriate Lyapunov-Krasovskii functionals, and employing the free weighting matrix method, several delay-dependent criteria for checking the global μ-stability of the complex-valued neural networks are established in LMIs. As direct applications of these results, several criteria on the exponential stability, power-stability, and log-stability are obtained. Two examples with simulations are provided to demonstrate the effectiveness of the proposed criteria.

  4. Delayed radiation neuropathy

    Energy Technology Data Exchange (ETDEWEB)

    Nagashima, T.; Miyamoto, K.; Beppu, H.; Hirose, K.; Yamada, K. (Tokyo Metropolitan Neurological Hospital (Japan))

    1981-07-01

    A case of cervical plexus neuropathy was reported in association with chronic radio-dermatitis, myxedema with thyroid adenoma and epiglottic tumor. A 38-year-old man has noticed muscle weakness and wasting of the right shoulder girdle since age 33. A detailed history taking revealed a previous irradiation to the neck because of the cervical lymphadenopathy at age 10 (X-ray 3,000 rads), keroid skin change at age 19, obesity and edema since 26, and hoarseness at 34. Laryngoscopic examination revealed a tumor on the right vocal cord, diagnosed as benign papilloma by histological study. In addition, there were chronic radio-dermatitis around the neck, primary hypothyroidism with a benign functioning adenoma on the right lobe of the thyroid, the right phrenic nerve palsy and the right recurrent nerve palsy. All these lesions were considered to be the late sequellae of radiation to the neck in childhood. Other neurological signs were weakness and amyotrophy of the right shoulder girdle with patchy sensory loss, and areflexia of the right arm. Gross power was fairly well preserved in the right hand. EMG showed neurogenic changes in the tested muscles, suggesting a peripheral nerve lesion. Nerve conduction velocities were normal. No abnormal findings were revealed by myelography and spinal CT. The neurological findings of the patient were compatible with the diagnosis of middle cervical plexus palsy apparently due to late radiation effect. In the literature eight cases of post-radiation neuropathy with a long latency have been reported. The present case with the longest latency after the radiation should be included in the series of the reported cases of ''delayed radiation neuropathy.'' (author).

  5. Congestion control algorithm in large-delay uncertain networks

    Institute of Scientific and Technical Information of China (English)

    Fengjie YIN; Yuanwei JING; Yuanjiu GONG

    2007-01-01

    Based on Smith-fuzzy controller,a new active queue management(AQM)algorithm adaptable to the large-delay uncertain networks is presented.It can compensate the negative impact on the queue stability caused by the large delay,and it also maintains strong robustness under the condition of dynamic network fluid.Its stability is proven through Lyapunov method.Simulation results demonstrated that this method enables the queue length to converge at a preset value quickly and keeps the queue oscillation small.the simulation results also show that the scheme is very robust to disturbance under various network conditions and large delay and,in particular,the algorithm proposed outperforms the conventional PI control and fuzzy control when the network parameters and network delay change.

  6. New results on robust exponential stability of integral delay systems

    Science.gov (United States)

    Melchor-Aguilar, Daniel

    2016-06-01

    The robust exponential stability of integral delay systems with exponential kernels is investigated. Sufficient delay-dependent robust conditions expressed in terms of linear matrix inequalities and matrix norms are derived by using the Lyapunov-Krasovskii functional approach. The results are combined with a new result on quadratic stabilisability of the state-feedback synthesis problem in order to derive a new linear matrix inequality methodology of designing a robust non-fragile controller for the finite spectrum assignment of input delay systems that guarantees simultaneously a numerically safe implementation and also the robustness to uncertainty in the system matrices and to perturbation in the feedback gain.

  7. Delay Induced Hopf Bifurcation of Small-World Networks

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper, the stability and the Hopf bifurcation of small-world networks with time delay are studied. By analyzing the change of delay, we obtain several sufficient conditions on stable and unstable properties. When the delay passes a critical value, a Hopf bifurcation may appear. Furthermore, the direction and the stability of bifurcating periodic solutions are investigated by the normal form theory and the center manifold reduction. At last, by numerical simulations, we further illustrate the effectiveness of theorems in this paper.

  8. Projective Synchronization Between Two Nonidentical Variable Time Delayed Systems

    Institute of Scientific and Technical Information of China (English)

    FENG Cun-Fang; WANG Ying-Hai

    2012-01-01

    In this paper, we propose a method for the projective synchronization between two different chaotic systems with variable time delays. Using active control approach, the suitable controller is constructed to make the states of two different diverse time delayed systems asymptotically synchronize up to the desired scaling factor. Based on the Lyapunov stability theory, the sufficient condition for the projective synchronization is calculated theoretically. Numerical simulations of the projective synchronization between Maekey-Glass system and Ikeda system with variable time delays are shown to validate the effectiveness of the proposed algorithm.

  9. A new surface acoustic wave (SAW) delay line sensor

    Science.gov (United States)

    Jha, Shashank S.; Yadava, R. D. S.

    2013-06-01

    We propose a new configuration for SAW chemical sensing. A polymer coated SAW delay line device provides the coupling for synchronization of two stable self-sustained limit cycle oscillators. The dependence of synchronization frequency on the SAW delay time has been made the basis for chemical sensing. The analysis has carried out under conditions of weak phase coupling [1]. The dependence of synchronization modes on coupling parameters is analyzed. The sensitivity of a synchronization branch for vapor sorption induced delay perturbations is analyzed. This analysis shows the possibility of realizing high performance SAW sensors by this approach.

  10. Solving the Linear 1D Thermoelasticity Equations with Pure Delay

    Directory of Open Access Journals (Sweden)

    Denys Ya. Khusainov

    2015-01-01

    Full Text Available We propose a system of partial differential equations with a single constant delay τ>0 describing the behavior of a one-dimensional thermoelastic solid occupying a bounded interval of R1. For an initial-boundary value problem associated with this system, we prove a well-posedness result in a certain topology under appropriate regularity conditions on the data. Further, we show the solution of our delayed model to converge to the solution of the classical equations of thermoelasticity as τ→0. Finally, we deduce an explicit solution representation for the delay problem.

  11. Dynamical Models of Dyadic Interactions with Delay

    CERN Document Server

    Bielczyk, Natalia; Płatkowski, Tadeusz

    2012-01-01

    When interpersonal interactions between individuals are described by the (discrete or continuous) dynamical systems, the interactions are usually assumed to be instantaneous: the rates of change of the actual states of the actors at given instant of time are assumed to depend on their states at the same time. In reality the natural time delay should be included in the corresponding models. We investigate a general class of linear models of dyadic interactions with a constant discrete time delay. We prove that in such models the changes of stability of the stationary points from instability to stability or vice versa occur for various intervals of the parameters which determine the intensity of interactions. The conditions guaranteeing arbitrary number (zero, one ore more) of switches are formulated and the relevant theorems are proved. A systematic analysis of all generic cases is carried out. It is obvious that the dynamics of interactions depend both on the strength of reactions of partners on their own sta...

  12. Delayed onset muscle soreness: is massage effective?

    Science.gov (United States)

    Nelson, Nicole

    2013-10-01

    Despite the widespread occurrence of delayed onset muscle soreness (DOMS), there is little consensus as to the exact cause or which treatments may be most effective at alleviating symptoms. Greater understanding of DOMS can give sports medicine and fitness professionals an opportunity to help prevent or speed recovery of this performance limiting condition. This article will review the DOMS literature, including the potential role of psychosocial factors and explore studies which involve massage therapy as a treatment modality. Articles from PubMed, MEDLINE, Google Scholar, and references from articles are included in this review. Search words and phrases included delayed onset muscle soreness, repeated bout effect, massage effectiveness, exercise induced muscle damage, and eccentric exercise.

  13. Dynamics of delayed piecewise linear systems

    Directory of Open Access Journals (Sweden)

    Laszlo E. Kollar

    2003-02-01

    Full Text Available In this paper the dynamics of the controlled pendulum is investigated assuming backlash and time delays. The upper equilibrium of the pendulum is stabilized by a piecewise constant control force which is the linear combination of the sampled values of the angle and the angular velocity of the pendulum. The control force is provided by a motor which drives one of the wheels of the cart through an elastic teeth belt. The contact between the teeth of the gear (rigid and the belt (elastic introduces a nonlinearity known as ``backlash" and causes the oscillation of the controlled pendulum around its upper equilibrium. The processing and sampling delays in the determination of the control force tend to destabilize the controlled system as well. We obtain conditions guaranteeing that the pendulum remains in the neighborhood of the upper equilibrium. Experimental findings obtained on a computer controlled inverted pendulum cart structure are also presented showing good agreement with the simulation results.

  14. Baclofen Withdrawal Presenting as Irritability in a Developmentally Delayed Child

    Directory of Open Access Journals (Sweden)

    C. Anthoney Lim

    2012-09-01

    Full Text Available Irritability in children has a broad differential diagnosis, ranging from benign processes to lifethreatening emergencies. In children with comorbid conditions and developmental delay, the diagnostic process becomes more challenging. This case report describes a developmentally delayed 14-year-old boy who presented with pain and crying caused by a malfunction of a surgically implanted baclofen pump. We describe recommendations concerning the diagnostic evaluation, medical management, and surgical repair.

  15. ABOUT HYBRID BIDIRECTIONAL ASSOCIATIVE MEMORY NEURAL NETWORKS WITH DISCRETE DELAYS

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this paper, hybrid bidirectional associative memory neural networks with discrete delays is considered. By ingeniously importing real parameters di > 0(i = 1,2,···,n) which can be adjusted, we establish some new sufficient conditions for the dynamical characteristics of hybrid bidirectional associative memory neural networks with discrete delays by the method of variation of parameters and some analysis techniques. Our results generalize and improve the related results in [10,11]. Our work is significant...

  16. Consensus of Heterogeneous Multiagent Systems with Arbitrarily Bounded Communication Delay

    Directory of Open Access Journals (Sweden)

    Xue Li

    2017-01-01

    Full Text Available This paper focuses on the consensus problem of high-order heterogeneous multiagent systems with arbitrarily bounded communication delays. Through the method of nonnegative matrices, we get a sufficient consensus condition for the systems with dynamically changing topology. The results of this paper show, even when there are arbitrarily bounded communication delays in the systems, all agents can reach a consensus no matter whether there are spanning trees for the corresponding communication graphs at any time.

  17. STABILITY OF TIME VARYING SINGULAR DIFFERENTIAL SYSTEMS WITH DELAY

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In this paper, stability of time varying singular differential systems with delay is considered. Based on variation formula and Gronwall-Bellman integral inequality, we obtain the exponential estimation of the solution and the sufficient conditions under which the considered system is stable and exponentially asymptotically stable. These results will be very useful to further research on Roust stability and control design of uncertain singular control systems with delay.

  18. Time Delay in Molecular Photoionization

    CERN Document Server

    Hockett, P; Villeneuve, D M; Corkum, P B

    2015-01-01

    Time-delays in the photoionization of molecules are investigated. As compared to atomic ionization, the time-delays expected from molecular ionization present a much richer phenomenon, with a strong spatial dependence due to the anisotropic nature of the molecular scattering potential. We investigate this from a scattering theory perspective, and make use of molecular photoionization calculations to examine this effect in representative homonuclear and hetronuclear diatomic molecules, nitrogen and carbon monoxide. We present energy and angle-resolved maps of the Wigner delay time for single-photon valence ionization, and discuss the possibilities for experimental measurements.

  19. New Delay-Dependent Stability Criteria for Uncertain Neutral Systems with Mixed Time-Varying Delays and Nonlinear Perturbations

    Directory of Open Access Journals (Sweden)

    Hamid Reza Karimi

    2009-01-01

    Full Text Available The problem of stability analysis for a class of neutral systems with mixed time-varying neutral, discrete and distributed delays and nonlinear parameter perturbations is addressed. By introducing a novel Lyapunov-Krasovskii functional and combining the descriptor model transformation, the Leibniz-Newton formula, some free-weighting matrices, and a suitable change of variables, new sufficient conditions are established for the stability of the considered system, which are neutral-delay-dependent, discrete-delay-range-dependent, and distributed-delay-dependent. The conditions are presented in terms of linear matrix inequalities (LMIs and can be efficiently solved using convex programming techniques. Two numerical examples are given to illustrate the efficiency of the proposed method.

  20. Robust H∞ Stabilization of Uncertain Linear Time-Delay System with Delayed/Undelayed State Feedback Controllers

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper focuses on the H∞ controller design for linear systems with time-varying delays and norm bounded parameter perturbetions in the system state and control/disturbance. On the existence of delayed/undelayed full state feedback controllers, we present a sufficient condition and give a design method in the form of Riccati equation. The controller can not only stabilize the time-delay system, but also make the H∞ norm of the closed-loop system be less than a given bound. This result practically generalizes the related results in current literature.

  1. Delay-Dependent Robust Exponential Stability for Uncertain Neutral Stochastic Systems with Interval Time-Varying Delay

    Directory of Open Access Journals (Sweden)

    Weihua Mao

    2012-01-01

    Full Text Available This paper discusses the mean-square exponential stability of uncertain neutral linear stochastic systems with interval time-varying delays. A new augmented Lyapunov-Krasovskii functional (LKF has been constructed to derive improved delay-dependent robust mean-square exponential stability criteria, which are forms of linear matrix inequalities (LMIs. By free-weight matrices method, the usual restriction that the stability conditions only bear slow-varying derivative of the delay is removed. Finally, numerical examples are provided to illustrate the effectiveness of the proposed method.

  2. STABILITY ANALYSIS OF HOPFIELD NEURAL NETWORKS WITH TIME DELAY

    Institute of Scientific and Technical Information of China (English)

    王林山; 徐道义

    2002-01-01

    The global asymptotic stability for Hopfield neural networks with time delay was investigated. A theorem and two corollaries were obtained, in which the boundedness and differentiability offjon R in some articles were deleted. Some sufficient conditions for the existence of global asymptotic stable equilibrium of the networks in this paper are better than the sufficient conditions in quoted articles.

  3. GLOBAL STABILITY IN HOPFIELD NEURAL NETWORKS WITH DISTRIBUTED TIME DELAYS

    Institute of Scientific and Technical Information of China (English)

    Zhang Jiye; Wu Pingbo; Dai Huanyun

    2001-01-01

    In this paper, without assuming the boundedness, monotonicity and differentiability of the activation functions, the conditions ensuring existence, uniqueness, and global asymptotical stability of the equilibrium point of Hopfield neural network models with distributed time delays are studied. Using M-matrix theory and constructing proper Liapunov functionals, the sufficient conditions for global asymptotic stability are obtained.

  4. Leibniz Dynamics with Time Delay

    OpenAIRE

    Albu, I. D.; Opris, D.

    2005-01-01

    In this paper we show that several dynamical systems with time delay can be described as vector fields associated to smooth functions via a bracket of Leibniz structure. Some examples illustrate the theoretical considerations.

  5. Delays and networked control systems

    CERN Document Server

    Hetel, Laurentiu; Daafouz, Jamal; Johansson, Karl

    2016-01-01

    This edited monograph includes state-of-the-art contributions on continuous time dynamical networks with delays. The book is divided into four parts. The first part presents tools and methods for the analysis of time-delay systems with a particular attention on control problems of large scale or infinite-dimensional systems with delays. The second part of the book is dedicated to the use of time-delay models for the analysis and design of Networked Control Systems. The third part of the book focuses on the analysis and design of systems with asynchronous sampling intervals which occur in Networked Control Systems. The last part of the book exposes several contributions dealing with the design of cooperative control and observation laws for networked control systems. The target audience primarily comprises researchers and experts in the field of control theory, but the book may also be beneficial for graduate students. .

  6. A Kac CROW Delay Line

    CERN Document Server

    Sumetsky, M

    2013-01-01

    A low-loss CROW delay line with a weak inter-resonator coupling determined by the Kac matrix is dispersionless and can be easily impedance-matched by adjusting the coupling to the input/output waveguide.

  7. Synchronization in coupled time-delayed systems with parameter mismatch and noise perturbation

    Science.gov (United States)

    Sun, Yongzheng; Ruan, Jiong

    2009-12-01

    In this paper, a design of coupling and effective sufficient condition for stable complete synchronization and antisynchronization of a class of coupled time-delayed systems with parameter mismatch and noise perturbation are established. Based on the LaSalle-type invariance principle for stochastic differential equations, sufficient conditions guaranteeing complete synchronization and antisynchronization with constant time delay are developed. Also delay-dependent sufficient conditions for the case of time-varying delay are derived by using the Lyapunov approach for stochastic differential equations. Numerical examples fully support the analytical results.

  8. Stability analysis of fractional-order Hopfield neural networks with time delays.

    Science.gov (United States)

    Wang, Hu; Yu, Yongguang; Wen, Guoguang

    2014-07-01

    This paper investigates the stability for fractional-order Hopfield neural networks with time delays. Firstly, the fractional-order Hopfield neural networks with hub structure and time delays are studied. Some sufficient conditions for stability of the systems are obtained. Next, two fractional-order Hopfield neural networks with different ring structures and time delays are developed. By studying the developed neural networks, the corresponding sufficient conditions for stability of the systems are also derived. It is shown that the stability conditions are independent of time delays. Finally, numerical simulations are given to illustrate the effectiveness of the theoretical results obtained in this paper.

  9. When good pigeons make bad decisions: Choice with probabilistic delays and outcomes.

    Science.gov (United States)

    Pisklak, Jeffrey M; McDevitt, Margaret A; Dunn, Roger M; Spetch, Marcia L

    2015-11-01

    Pigeons chose between an (optimal) alternative that sometimes provided food after a 10-s delay and other times after a 40-s delay and another (suboptimal) alternative that sometimes provided food after 10 s but other times no food after 40 s. When outcomes were not signaled during the delays, pigeons strongly preferred the optimal alternative. When outcomes were signaled, choices of the suboptimal alternative increased and most pigeons preferred the alternative that provided no food after the long delay despite the cost in terms of obtained food. The pattern of results was similar whether the short delays occurred on 25% or 50% of the trials. Shortening the 40-s delay to food sharply reduced suboptimal choices, but shortening the delay to no food had little effect. The results suggest that a signaled delay to no food does not punish responding in probabilistic choice procedures. The findings are discussed in terms of conditioned reinforcement by signals for good news.

  10. Systematics in delayed neutron yields

    Energy Technology Data Exchange (ETDEWEB)

    Ohsawa, Takaaki [Kinki Univ., Higashi-Osaka, Osaka (Japan). Atomic Energy Research Inst.

    1998-03-01

    An attempt was made to reproduce the systematic trend observed in the delayed neutron yields for actinides on the basis of the five-Gaussian representation of the fission yield together with available data sets for delayed neutron emission probability. It was found that systematic decrease in DNY for heavier actinides is mainly due to decrease of fission yields of precursors in the lighter side of the light fragment region. (author)

  11. Time Delay in Molecular Photoionization

    OpenAIRE

    Hockett, P.; Frumker, E.; Villeneuve, D M; Corkum, P. B.

    2015-01-01

    Time-delays in the photoionization of molecules are investigated. As compared to atomic ionization, the time-delays expected from molecular ionization present a much richer phenomenon, with a strong spatial dependence due to the anisotropic nature of the molecular scattering potential. We investigate this from a scattering theory perspective, and make use of molecular photoionization calculations to examine this effect in representative homonuclear and hetronuclear diatomic molecules, nitroge...

  12. A new approach to consensus problems in discrete-time multiagent systems with time-delays

    Institute of Scientific and Technical Information of China (English)

    WANG Long; XIAO Feng

    2007-01-01

    In this paper, consensus problems in discrete-time multiagent systems with timeinvariant delays are considered. In order to characterize the structures of communication topologies, the concept of "pre-leader-follower" decomposition is introduced.Then, a necessary and sufficient condition for state consensus is established. By this method, consensus problems in networks with a single time-delay, as well as with multiple time-delays, are studied, and some necessary and sufficient conditions for solvability of consensus problems are obtained.

  13. Basin stability in delayed dynamics

    Science.gov (United States)

    Leng, Siyang; Lin, Wei; Kurths, Jürgen

    2016-02-01

    Basin stability (BS) is a universal concept for complex systems studies, which focuses on the volume of the basin of attraction instead of the traditional linearization-based approach. It has a lot of applications in real-world systems especially in dynamical systems with a phenomenon of multi-stability, which is even more ubiquitous in delayed dynamics such as the firing neurons, the climatological processes, and the power grids. Due to the infinite dimensional property of the space for the initial values, how to properly define the basin’s volume for delayed dynamics remains a fundamental problem. We propose here a technique which projects the infinite dimensional initial state space to a finite-dimensional Euclidean space by expanding the initial function along with different orthogonal or nonorthogonal basis. A generalized concept of basin’s volume in delayed dynamics and a highly practicable calculating algorithm with a cross-validation procedure are provided to numerically estimate the basin of attraction in delayed dynamics. We show potential applicabilities of this approach by applying it to study several representative systems of biological or/and physical significance, including the delayed Hopfield neuronal model with multistability and delayed complex networks with synchronization dynamics.

  14. Duration reproduction with sensory feedback delay: Differential involvement of perception and action time

    Directory of Open Access Journals (Sweden)

    Stephanie eGanzenmüller

    2012-10-01

    Full Text Available Previous research has shown that voluntary action can attract subsequent, delayed feedback events towards the action, and adaptation to the sensorimotor delay can even reverse motor-sensory temporal-order judgments. However, whether and how sensorimotor delay affects duration reproduction is still unclear. To investigate this, we injected an onset- or offset-delay to the sensory feedback signal from a duration reproduction task. We compared duration reproductions within (visual, auditory modality and across audiovisual modalities with feedback signal onset- and offset-delay manipulations. We found that the reproduced duration was lengthened in both visual and auditory feedback signal onset-delay conditions. The lengthening effect was evident immediately, on the first trial with the onset delay. However, when the onset of the feedback signal was prior to the action, the lengthening effect was diminished. In contrast, a shortening effect was found with feedback signal offset-delay, though the effect was weaker and manifested only in the auditory offset-delay condition. These findings indicate that participants tend to mix the onset of action and the feedback signal more when the feedback is delayed, and they heavily rely on motor-stop signals for the duration reproduction. Furthermore, auditory duration was overestimated compared to visual duration in crossmodal feedback conditions, and the overestimation of auditory duration (or the underestimation of visual duration was independent of the delay manipulation.

  15. Delays to the diagnosis of cervical dystonia.

    Science.gov (United States)

    Bertram, Kelly L; Williams, David R

    2016-03-01

    The diagnosis of cervical dystonia (CD) is based on physical examination and is therefore reliant on clinician experience. Due to variability of presenting symptoms it may be misdiagnosed, thus delaying the provision of effective treatment. We sought to determine the average time taken to make a diagnosis of CD in our clinical cohort and explore contributing factors to diagnostic delay. Forty-nine patients with a diagnosis of CD attending a movement disorder specialist for treatment completed a questionnaire regarding symptoms and clinical interactions at onset and diagnosis. The mean time from symptom onset to diagnosis was 6.8 years (range 0-53 years). More than 50% of patients sought physical therapies initially, prior to consulting their general practitioner. Only 40% of patients sought medical advice within the first 6 months of symptom onset and only 10% were given an initial diagnosis of CD. The first referral from the general practitioner was to a specialist other than a neurologist in 31% of patients. Patients were seen by a mean of three doctors (range one to nine) before being given the correct diagnosis of CD. Delay to diagnosis of CD may in part be due to lack of awareness of the condition amongst health care professionals. Improved diagnostic skill appears likely to have had a substantial impact on the delivery of appropriate treatment in this population.

  16. Delay-Dependent Exponential Stability of Stochastic Delayed Recurrent Neural Networks with Markovian Switching

    Institute of Scientific and Technical Information of China (English)

    LIU Hai-feng; WANG Chun-hua; WEI Guo-liang

    2008-01-01

    The exponential stability problem is investigated fora class of stochastic recurrent neural networks with time delay and Markovian switching.By using It(o)'s differential formula and the Lyapunov stabifity theory,sufficient condition for the solvability of this problem is derived in telm of linear matrix inequalities,which can be easily checked by resorting to available software packages.A numerical example and the simulation are exploited to demonstrate the effectiveness of the proposed results.

  17. Car Delay Model near Bus Stops with Mixed Traffic Flow

    Directory of Open Access Journals (Sweden)

    Yang Xiaobao

    2013-01-01

    Full Text Available This paper proposes a model for estimating car delays at bus stops under mixed traffic using probability theory and queuing theory. The roadway is divided to serve motorized and nonmotorized traffic streams. Bus stops are located on the nonmotorized lanes. When buses dwell at the stop, they block the bicycles. Thus, two conflict points between car stream and other traffic stream are identified. The first conflict point occurs as bicycles merge to the motorized lane to avoid waiting behind the stopping buses. The second occurs as buses merge back to the motorized lane. The average car delay is estimated as the sum of the average delay at these two conflict points and the delay resulting from following the slower bicycles that merged into the motorized lane. Data are collected to calibrate and validate the developed model from one site in Beijing. The sensitivity of car delay to various operation conditions is examined. The results show that both bus stream and bicycle stream have significant effects on car delay. At bus volumes above 200 vehicles per hour, the curbside stop design is not appropriate because of the long car delays. It can be replaced by the bus bay design.

  18. Analysing Social Epidemics by Delayed Stochastic Models

    Directory of Open Access Journals (Sweden)

    Francisco-José Santonja

    2012-01-01

    Full Text Available We investigate the dynamics of a delayed stochastic mathematical model to understand the evolution of the alcohol consumption in Spain. Sufficient condition for stability in probability of the equilibrium point of the dynamic model with aftereffect and stochastic perturbations is obtained via Kolmanovskii and Shaikhet general method of Lyapunov functionals construction. We conclude that alcohol consumption in Spain will be constant (with stability in time with around 36.47% of nonconsumers, 62.94% of nonrisk consumers, and 0.59% of risk consumers. This approach allows us to emphasize the possibilities of the dynamical models in order to study human behaviour.

  19. The Effect of D-Cycloserine on Immediate vs. Delayed Extinction of Learned Fear

    Science.gov (United States)

    Langton, Julia M.; Richardson, Rick

    2010-01-01

    We compared the effect of D-cycloserine (DCS) on immediate (10 min after conditioning) and delayed (24 h after conditioning) extinction of learned fear in rats. DCS facilitated both immediate and delayed extinction when the drug was administered after extinction training. However, DCS did not facilitate immediate extinction when administered prior…

  20. Changing Delay Discounting in the Light of the Competing Neurobehavioral Decision Systems Theory: A Review

    Science.gov (United States)

    Koffarnus, Mikhail N.; Jarmolowicz, David P.; Mueller, E. Terry; Bickel, Warren K.

    2013-01-01

    Excessively devaluing delayed reinforcers co-occurs with a wide variety of clinical conditions such as drug dependence, obesity, and excessive gambling. If excessive delay discounting is a trans-disease process that underlies the choice behavior leading to these and other negative health conditions, efforts to change an individual's discount rate…

  1. Synchronization and Exponential Estimates of Complex Networks with Mixed Time-varying Coupling Delays

    Institute of Scientific and Technical Information of China (English)

    Yang Dai; YunZe Cai; Xiao-Ming Xu

    2009-01-01

    Exponential estimates and sufficient conditions for the exponential synchronization of complex dynamical networks with bounded time-varying delays are given in terms of linear matrix inequalities (LMIs). A generalized complex networks model involving both neutral delays and retarded ones is presented. The exponential synchronization problem of the complex networks is converted equivalently into the exponential stability problem of a group of uncorrelated delay functional differential equations with mixed time-varying delays. By utilizing the free weighting matrix technique, a less conservative delay-dependent synchronization criterion is derived. An illustrative example is provided to demonstrate the effectiveness of the proposed method.

  2. Synchronization of Memristor-Based Coupling Recurrent Neural Networks With Time-Varying Delays and Impulses.

    Science.gov (United States)

    Zhang, Wei; Li, Chuandong; Huang, Tingwen; He, Xing

    2015-12-01

    Synchronization of an array of linearly coupled memristor-based recurrent neural networks with impulses and time-varying delays is investigated in this brief. Based on the Lyapunov function method, an extended Halanay differential inequality and a new delay impulsive differential inequality, some sufficient conditions are derived, which depend on impulsive and coupling delays to guarantee the exponential synchronization of the memristor-based recurrent neural networks. Impulses with and without delay and time-varying delay are considered for modeling the coupled neural networks simultaneously, which renders more practical significance of our current research. Finally, numerical simulations are given to verify the effectiveness of the theoretical results.

  3. Delay time modulation induced oscillating synchronization and intermittent anticipatory/lag and complete synchronizations in time-delay nonlinear dynamical systems.

    Science.gov (United States)

    Senthilkumar, D V; Lakshmanan, M

    2007-03-01

    Existence of a new type of oscillating synchronization that oscillates between three different types of synchronizations (anticipatory, complete, and lag synchronizations) is identified in unidirectionally coupled nonlinear time-delay systems having two different time-delays, that is feedback delay with a periodic delay time modulation and a constant coupling delay. Intermittent anticipatory, intermittent lag, and complete synchronizations are shown to exist in the same system with identical delay time modulations in both the delays. The transition from anticipatory to complete synchronization and from complete to lag synchronization as a function of coupling delay with suitable stability condition is discussed. The intermittent anticipatory and lag synchronizations are characterized by the minimum of the similarity functions and the intermittent behavior is characterized by a universal asymptotic -32 power law distribution. It is also shown that the delay time carved out of the trajectories of the time-delay system with periodic delay time modulation cannot be estimated using conventional methods, thereby reducing the possibility of decoding the message by phase space reconstruction.

  4. Reaction diffusion equation with spatio-temporal delay

    Science.gov (United States)

    Zhao, Zhihong; Rong, Erhua

    2014-07-01

    We investigate reaction-diffusion equation with spatio-temporal delays, the global existence, uniqueness and asymptotic behavior of solutions for which in relation to constant steady-state solution, included in the region of attraction of a stable steady solution. It is shown that if the delay reaction function satisfies some conditions and the system possesses a pair of upper and lower solutions then there exists a unique global solution. In terms of the maximal and minimal constant solutions of the corresponding steady-state problem, we get the asymptotic stability of reaction-diffusion equation with spatio-temporal delay. Applying this theory to Lotka-Volterra model with spatio-temporal delay, we get the global solution asymptotically tend to the steady-state problem's steady-state solution.

  5. Global attractivity in delayed Cohen-Grossberg neural network models

    Energy Technology Data Exchange (ETDEWEB)

    Li, C.-H. [Department of Mathematics, National Central University, Jhongli City 32001, Taiwan (China)], E-mail: 93241006@cc.ncu.edu.tw; Yang, S.-Y. [Department of Mathematics, National Central University, Jhongli City 32001, Taiwan (China)], E-mail: syyang@math.ncu.edu.tw

    2009-02-28

    In this paper, we investigate the global attractivity of Cohen-Grossberg neural network models with connection time delays for both discrete and distributed cases via the Lyapunov functional method. Without assuming the monotonicity and differentiability of activation functions and the symmetry of connection matrix, we establish three new sufficient conditions for the global exponential stability of a unique equilibrium for the delayed Cohen-Grossberg neural network no matter whether the connection time delay is of discrete type or distributed type. In particular, all the three new criteria are independent of time delays and do not include one another. To demonstrate the differences and features of the new stability criteria, several examples are discussed to compare the present results with the existing ones.

  6. Different Types of Synchronization in Time-Delayed Systems

    Institute of Scientific and Technical Information of China (English)

    FENG Cun-Fang; ZHANG Yan; WANG Ying-Hai

    2007-01-01

    @@ We investigate different types of synchronization between two unidirectionally nonlinearly coupled identical delaydifferential systems related to optical bistable or hybrid optical bistable devices. This system can represent some kinds of delay-differential models, I.e. Ikeda model, Vallée model, sine-square model, Mackey-Glass model, and so on. We find existence and sufficient stability conditions by theoretical analysis and test the correctness by numerical simulations. Lag, complete and anticipating synchronization are observed, respectively. It is found that the time-delay system can be divided into two parts, one is the instant term and the other is the delay term.Synchronization between two identical chaotic systems can be derived by adding a coupled term to the delay term in the driven system.

  7. Complete chaotic synchronization in mutually coupled time-delay systems.

    Science.gov (United States)

    Landsman, Alexandra S; Schwartz, Ira B

    2007-02-01

    Complete chaotic synchronization of end lasers has been observed in a line of mutually coupled, time-delayed system of three lasers, with no direct communication between the end lasers. The present paper uses ideas from generalized synchronization to explain the complete synchronization in the presence of long coupling delays, applied to a model of mutually coupled semiconductor lasers in a line. These ideas significantly simplify the analysis by casting the stability in terms of the local dynamics of each laser. The variational equations near the synchronization manifold are analyzed, and used to derive the synchronization condition that is a function of parameters. The results explain and predict the dependence of synchronization on various parameters, such as time delays, strength of coupling and dissipation. The ideas can be applied to understand complete synchronization in other chaotic systems with coupling delays and no direct communication between synchronized subsystems.

  8. Exact synchronization bound for coupled time-delay systems

    Science.gov (United States)

    Senthilkumar, D. V.; Pesquera, Luis; Banerjee, Santo; Ortín, Silvia; Kurths, J.

    2013-04-01

    We obtain an exact bound for synchronization in coupled time-delay systems using the generalized Halanay inequality for the general case of time-dependent delay, coupling, and coefficients. Furthermore, we show that the same analysis is applicable to both uni- and bidirectionally coupled time-delay systems with an appropriate evolution equation for their synchronization manifold, which can also be defined for different types of synchronization. The exact synchronization bound assures an exponential stabilization of the synchronization manifold which is crucial for applications. The analytical synchronization bound is independent of the nature of the modulation and can be applied to any time-delay system satisfying a Lipschitz condition. The analytical results are corroborated numerically using the Ikeda system.

  9. Linearisation via input-output injection of time delay systems

    Science.gov (United States)

    García-Ramírez, Eduardo; Moog, Claude H.; Califano, Claudia; Alejandro Márquez-Martínez, Luis

    2016-06-01

    This paper deals with the problem of linearisation of systems with constant commensurable delays by input-output injection using algebraic control tools based on the theory of non-commutative rings. Solutions for the problem of linearisation free of delays, and with delays of an observable nonlinear time-delay systems are presented based on the analysis of the input-output equation. These results are achieved by means of constructive algorithms that use the nth derivative of the output expressed in terms of the state-space variables instead of the explicit computation of the input-output representation of the system. Necessary and sufficient conditions are established in both cases by means of an invertible change of coordinates.

  10. Backstepping tracking control for nonlinear time-delay systems

    Institute of Scientific and Technical Information of China (English)

    Chen Weisheng; Li Junmin

    2006-01-01

    Two design approaches of state feedback and output feedback tracking controllers are proposed for a class of strict feedback nonlinear time-delay systems by using backstepping technique. When the states of system cannot be observed, the time-delay state observer is designed to estimate the system states. Domination method is used to deal with nonlinear time-delay function under the assumption that the nonlinear time-delay functions of systems satisfy Lipschitz condition. The global asymptotical tracking of the references signal is achieved and the bound of all signals of the resultant closed-loop system is also guaranteed. By constructing a Lyapunov-Krasoviskii functional, the stability of the closed-loop system is proved. The feasibility of the proposed approach is illustrated by a simulation example.

  11. Adaptive synchronization under almost every initial data for stochastic neural networks with time-varying delays and distributed delays

    Science.gov (United States)

    Zhu, Quanxin; Cao, Jinde

    2011-04-01

    This paper is concerned with the adaptive synchronization problem for a class of stochastic delayed neural networks. Based on the LaSalle invariant principle of stochastic differential delay equations and the stochastic analysis theory as well as the adaptive feedback control technique, a linear matrix inequality approach is developed to derive some novel sufficient conditions achieving complete synchronization of unidirectionally coupled stochastic delayed neural networks. In particular, the synchronization criterion considered in this paper is the globally almost surely asymptotic stability of the error dynamical system, which has seldom been applied to investigate the synchronization problem. Moreover, the delays proposed in this paper are time-varying delays and distributed delays, which have rarely been used to study the synchronization problem for coupled stochastic delayed neural networks. Therefore, the results obtained in this paper are more general and useful than those given in the previous literature. Finally, two numerical examples and their simulations are provided to demonstrate the effectiveness of the theoretical results.

  12. Robust stability of discrete-time nonlinear system with time-delay

    Institute of Scientific and Technical Information of China (English)

    LIU Xin-ge; WU Min

    2005-01-01

    The robustly asymptotical stability problem for discrete-time nonlinear systems with time-delay was investigated. Positive definite matrix are constructed through Lyapunov functional. With the identity transform, property of matrix inverse and S-procedure, a new sufficient condition independent of the size of time-delay for robust stability of discrete-time nonlinear systems with time-delay is established. With Schur complement, another equivalent sufficient condition for robust stability of discrete-time nonlinear systems with time-delay is given. Finally, a sufficient condition dependent on the size of time-delay for robust stability of discrete-time nonlinear systems with time-delay is obtained. A unified approach is used to cast the robust stability problem into a convex optimization involving linear matrix inequalities.

  13. On the Global Dissipativity of a Class of Cellular Neural Networks with Multipantograph Delays

    Directory of Open Access Journals (Sweden)

    Liqun Zhou

    2011-01-01

    Full Text Available For the first time the global dissipativity of a class of cellular neural networks with multipantograph delays is studied. On the one hand, some delay-dependent sufficient conditions are obtained by directly constructing suitable Lyapunov functionals; on the other hand, firstly the transformation transforms the cellular neural networks with multipantograph delays into the cellular neural networks with constant delays and variable coefficients, and then constructing Lyapunov functionals, some delay-independent sufficient conditions are given. These new sufficient conditions can ensure global dissipativity together with their sets of attraction and can be applied to design global dissipative cellular neural networks with multipantograph delays and easily checked in practice by simple algebraic methods. An example is given to illustrate the correctness of the results.

  14. Structural Properties and Estimation of Delay Systems. Ph.D. Thesis

    Science.gov (United States)

    Kwong, R. H. S.

    1975-01-01

    Two areas in the theory of delay systems were studied: structural properties and their applications to feedback control, and optimal linear and nonlinear estimation. The concepts of controllability, stabilizability, observability, and detectability were investigated. The property of pointwise degeneracy of linear time-invariant delay systems is considered. Necessary and sufficient conditions for three dimensional linear systems to be made pointwise degenerate by delay feedback were obtained, while sufficient conditions for this to be possible are given for higher dimensional linear systems. These results were applied to obtain solvability conditions for the minimum time output zeroing control problem by delay feedback. A representation theorem is given for conditional moment functionals of general nonlinear stochastic delay systems, and stochastic differential equations are derived for conditional moment functionals satisfying certain smoothness properties.

  15. Shock Tube Ignition Delay Data Affected by Localized Ignition Phenomena

    KAUST Repository

    Javed, Tamour

    2016-12-29

    Shock tubes have conventionally been used for measuring high-temperature ignition delay times ~ O(1 ms). In the last decade or so, the operating regime of shock tubes has been extended to lower temperatures by accessing longer observation times. Such measurements may potentially be affected by some non-ideal phenomena. The purpose of this work is to measure long ignition delay times for fuels exhibiting negative temperature coefficient (NTC) and to assess the impact of shock tube non-idealities on ignition delay data. Ignition delay times of n-heptane and n-hexane were measured over the temperature range of 650 – 1250 K and pressures near 1.5 atm. Driver gas tailoring and long length of shock tube driver section were utilized to measure ignition delay times as long as 32 ms. Measured ignition delay times agree with chemical kinetic models at high (> 1100 K) and low (< 700 K) temperatures. In the intermediate temperature range (700 – 1100 K), however, significant discrepancies are observed between the measurements and homogeneous ignition delay simulations. It is postulated, based on experimental observations, that localized ignition kernels could affect the ignition delay times at the intermediate temperatures, which lead to compression (and heating) of the bulk gas and result in expediting the overall ignition event. The postulate is validated through simple representative computational fluid dynamic simulations of post-shock gas mixtures which exhibit ignition advancement via a hot spot. The results of the current work show that ignition delay times measured by shock tubes may be affected by non-ideal phenomena for certain conditions of temperature, pressure and fuel reactivity. Care must, therefore, be exercised in using such data for chemical kinetic model development and validation.

  16. Maximal regularity of second order delay equations in Banach spaces

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    We give necessary and sufficient conditions of Lp-maximal regularity(resp.B sp ,q-maximal regularity or F sp ,q-maximal regularity) for the second order delay equations:u″(t)=Au(t) + Gu’t + F u t + f(t), t ∈ [0, 2π] with periodic boundary conditions u(0)=u(2π), u′(0)=u′(2π), where A is a closed operator in a Banach space X,F and G are delay operators on Lp([-2π, 0];X)(resp.Bsp ,q([2π, 0];X) or Fsp,q([-2π, 0;X])).

  17. Chaos and Synchronization in Delayed System : Applications to Laser Networks

    Directory of Open Access Journals (Sweden)

    Schöll Eckehard

    2013-05-01

    Full Text Available We discuss recent results on chaos synchronization of delayed systems. We investigate the limit of large coupling delays and discuss how in this limit the stability problem for the synchronized solution is drastically simplified. We use these results to derive rigorous conditions for chaos synchronization of all-optically coupled laser networks. In laser systems the optical coupling phases have to be taken into account and give rise to interference conditions. We show that the relative phases between lasers can be used to optimize the effective coupling matrix.

  18. Finite-Dimensional Representations for Controlled Diffusions with Delay

    Energy Technology Data Exchange (ETDEWEB)

    Federico, Salvatore, E-mail: salvatore.federico@unimi.it [Università di Milano, Dipartimento di Economia, Management e Metodi Quantitativi (Italy); Tankov, Peter, E-mail: tankov@math.univ-paris-diderot.fr [Université Paris Diderot, Laboratoire de Probabilités et Modèles Aléatoires (France)

    2015-02-15

    We study stochastic delay differential equations (SDDE) where the coefficients depend on the moving averages of the state process. As a first contribution, we provide sufficient conditions under which the solution of the SDDE and a linear path functional of it admit a finite-dimensional Markovian representation. As a second contribution, we show how approximate finite-dimensional Markovian representations may be constructed when these conditions are not satisfied, and provide an estimate of the error corresponding to these approximations. These results are applied to optimal control and optimal stopping problems for stochastic systems with delay.

  19. Delays and user performance in human-computer-network interaction tasks.

    Science.gov (United States)

    Caldwell, Barrett S; Wang, Enlie

    2009-12-01

    This article describes a series of studies conducted to examine factors affecting user perceptions, responses, and tolerance for network-based computer delays affecting distributed human-computer-network interaction (HCNI) tasks. HCNI tasks, even with increasing computing and network bandwidth capabilities, are still affected by human perceptions of delay and appropriate waiting times for information flow latencies. Conducted were 6 laboratory studies with university participants in China (Preliminary Experiments 1 through 3) and the United States (Experiments 4 through 6) to examine users' perceptions of elapsed time, effect of perceived network task performance partners on delay tolerance, and expectations of appropriate delays based on task, situation, and network conditions. Results across the six experiments indicate that users' delay tolerance and estimated delay were affected by multiple task and expectation factors, including task complexity and importance, situation urgency and time availability, file size, and network bandwidth capacity. Results also suggest a range of user strategies for incorporating delay tolerance in task planning and performance. HCNI user experience is influenced by combinations of task requirements, constraints, and understandings of system performance; tolerance is a nonlinear function of time constraint ratios or decay. Appropriate user interface tools providing delay feedback information can help modify user expectations and delay tolerance. These tools are especially valuable when delay conditions exceed a few seconds or when task constraints and system demands are high. Interface designs for HCNI tasks should consider assistant-style presentations of delay feedback, information freshness, and network characteristics. Assistants should also gather awareness of user time constraints.

  20. Fundamentals of Delayed Coking Joint Industry Project

    Energy Technology Data Exchange (ETDEWEB)

    Michael Volk; Keith Wisecarver

    2004-09-26

    is 2,937,439 barrels/calendar day. These cokers produce 154,607 tons of coke per day and delayed coking accounts for 88% of the world capacity. The delayed coking charge capacity in the United States is 1,787,860 b/cd. Despite its wide commercial use, only relatively few contractors and refiners are truly knowledgeable in delayed-coking design, so that this process carries with it a ''black art'' connotation. Until recently, the expected yield from cokers was determined by a simple laboratory test on the feedstock. As a result of Tulsa University's prior related research, a process model was developed that with additional work could be used to optimize existing delayed cokers over a wide range of potential feedstocks and operating conditions. The objectives of this research program are to: utilize the current micro, batch and pilot unit facilities at The University of Tulsa to enhance the understanding of the coking process; conduct additional micro and pilot unit tests with new and in-house resids and recycles to make current optimization models more robust; conduct focused kinetic experiments to enhance the furnace tube model and to enhance liquid production while minimizing sulfur in the products; conduct detailed foaming studies to optimize the process and minimize process upsets; quantify the parameters that affect coke morphology; and to utilize the knowledge gained from the experimental and modeling studies to enhance the computer programs developed in the previous JIP for optimization of the coking process. These refined computer models will then be tested against refinery data provided by the member companies. Novel concepts will also be explored for hydrogen sulfide removal of furnace gases as well as gas injection studies to reduce over-cracking.

  1. Fundamentals of Delayed Coking Joint Industry Project

    Energy Technology Data Exchange (ETDEWEB)

    Michael Volk; Keith Wisecarver

    2003-09-26

    is 2,937,439 barrels/calendar day. These cokers produce 154,607 tons of coke per day and delayed coking accounts for 88% of the world capacity. The delayed coking charge capacity in the United States is 1,787,860 b/cd. Despite its wide commercial use, only relatively few contractors and refiners are truly knowledgeable in delayed-coking design, so that this process carries with it a ''black art'' connotation. Until recently, the expected yield from cokers was determined by a simple laboratory test on the feedstock. As a result of Tulsa University's prior related research, a process model was developed that with additional work could be used to optimize existing delayed cokers over a wide range of potential feedstocks and operating conditions. The objectives of this research program are to: utilize the current micro, batch and pilot unit facilities at The University of Tulsa to enhance the understanding of the coking process; conduct additional micro and pilot unit tests with new and in-house resids and recycles to make current optimization models more robust; conduct focused kinetic experiments to enhance the furnace tube model and to enhance liquid production while minimizing sulfur in the products; conduct detailed foaming studies to optimize the process and minimize process upsets; quantify the parameters that affect coke morphology; and to utilize the knowledge gained from the experimental and modeling studies to enhance the computer programs developed in the previous JIP for optimization of the coking process. These refined computer models will then be tested against refinery data provided by the member companies. Novel concepts will also be explored for hydrogen sulfide removal of furnace gases as well as gas injection studies to reduce over-cracking.

  2. 49 CFR 236.563 - Delay time.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Delay time. 236.563 Section 236.563 Transportation... Cab Signal Systems Rules and Instructions; Locomotives § 236.563 Delay time. Delay time of automatic... requirements of § 236.24 shall take into consideration the delay time....

  3. Stochastic modelling of train delays and delay propagation in stations

    NARCIS (Netherlands)

    Yuan, J.

    2006-01-01

    A trade-off exists between efficiently utilizing the capacity of railway networks and improving the reliability and punctuality of train operations. This dissertation presents a new analytical probability model based on blocking time theory which estimates the knock-on delays of trains caused by

  4. Delaying vortex breakdown by waves

    Science.gov (United States)

    Yao, M. F.; Jiang, L. B.; Wu, J. Z.; Ma, H. Y.; Pan, J. Y.

    1989-03-01

    The effect of spiral waves on delaying vortex breakdown in a tube is studied experimentally and theoretically. When a harmonic oscillation was imposed on one of guiding vanes in the tube, the breakdown was observed to be postponed appreciately. According to the generalized Lagrangian mean theory, proper forcing spiral waves may produce an additional streaming momentum, of which the effect is favorable and similar to an axial suction at downstream end. The delayed breakdown position is further predicted by using nonlinear wave theory. Qualitative agreement between theory and experiment is obtained, and experimental comparison of the effects due to forcing spiral wave and axial suction is made.

  5. Delay equations and radiation damping

    Science.gov (United States)

    Chicone, C.; Kopeikin, S. M.; Mashhoon, B.; Retzloff, D. G.

    2001-06-01

    Starting from delay equations that model field retardation effects, we study the origin of runaway modes that appear in the solutions of the classical equations of motion involving the radiation reaction force. When retardation effects are small, we argue that the physically significant solutions belong to the so-called slow manifold of the system and we identify this invariant manifold with the attractor in the state space of the delay equation. We demonstrate via an example that when retardation effects are no longer small, the motion could exhibit bifurcation phenomena that are not contained in the local equations of motion.

  6. Delay-dependent finite-time boundedness of a class of Markovian switching neural networks with time-varying delays.

    Science.gov (United States)

    Zhong, Qishui; Cheng, Jun; Zhao, Yuqing

    2015-07-01

    In this paper, a novel method is developed for delay-dependent finite-time boundedness of a class of Markovian switching neural networks with time-varying delays. New sufficient condition for stochastic boundness of Markovian jumping neural networks is presented and proved by an newly augmented stochastic Lyapunov-Krasovskii functional and novel activation function conditions, the state trajectory remains in a bounded region of the state space over a given finite-time interval. Finally, a numerical example is given to illustrate the efficiency and less conservative of the proposed method.

  7. Plate acoustic waves for low frequency delay line delaying signals up to 0.5 ms

    Science.gov (United States)

    Zaitsev, B. D.; Kuznetsova, I. E.; Zemnyukov, N. E.; Proidakov, V. I.; Teplykh, A. A.

    2010-01-01

    At present time there exists the problem of development of main memory elements based on the delay of electromagnetic signal with frequency of ˜100 kHz on hundreds microseconds. This paper is devoted to theoretical and experimental investigation of the possibility of development of corresponding acoustic delay lines. It was supposed to use the antisymmetric acoustic waves of zero order propagating in thin (compared to wavelength) metal plates. In this connection, we theoretically studied the parameters of A0 waves propagating in plates of various metals such as brass, bronze, copper, steel, and aluminum. For analysis of wave propagation in aforementioned plates, we used the standard motion equation and constitutive material equation for investigated medium as well as corresponding mechanical boundary conditions. As a result, the phase and group velocities versus parameter hf (h= plate thickness, f= wave frequency) were calculated for A0 wave propagating in mentioned above plates. It has been found that for steel plate the delay time about 0.5 ms can be achieved at the lengths of waveguide L=0.373, 0.737, and 0.971 m for h=0.175, 0.5, and 1.0 mm, respectively at f=120 kHz. The theoretical results were verified by experiment, which showed the possibility of development of corresponding delay lines with delay time ˜500 mks and acceptable insertion loss. In experiments, the excitation and reception of A0 waves were performed by the standard piezoelectric transducers of longitudinal waves and prismatic steel concentrators. The details of theoretical analysis and experiment are described.

  8. GLOBAL STABILITY ANALYSIS IN CELLULAR NEURAL NETWORKS WITH UNBOUNDED TIME DELAYS

    Institute of Scientific and Technical Information of China (English)

    张继业

    2004-01-01

    Without assuming the boundedness and differentiability of the activation functions,the conditions ensuring existence,uniqueness,and global asymptotical stability of the equilibrium point of cellular neural networks with unbounded time delays and variable delays were studied.Using the idea of vector Liapunov method,the intero-differential inequalities with unbounded delay and variable delays were constructed.By the stability analysis of the intero-differential inequalities,the sufficient conditions for global asymptotic stability of cellular neural networks were obtained.

  9. Containment consensus with measurement noises and time-varying communication delays

    Institute of Scientific and Technical Information of China (English)

    周峰; 王正杰; 范宁军

    2015-01-01

    In this paper, we consider the containment consensus control problem for multi-agent systems with measurement noises and time-varying communication delays under directed networks. By using stochastic analysis tools and algebraic graph theory, we prove that the followers can converge to the convex hull spanned by the leaders in the sense of mean square if the allowed upper bound of the time-varying delays satisfies a certain sufficient condition. Moreover, the time-varying delays are asymmetric for each follower agent, and the time-delay-dependent consensus condition is derived. Finally, numerical simulations are provided to illustrate the effectiveness of the obtained theoretical results.

  10. On Robust Stability of a Class of Uncertain Nonlinear Systems with Time-Varying Delay

    Institute of Scientific and Technical Information of China (English)

    NIAN Xiao-hong

    2002-01-01

    The problem of robust stability of a class of uncertain nonlinear dynamical systems with time-delay is considered. Based on the assumption that the nominal system is stable, some sufficient conditions onrobust stability of uncertain nonlinear dynamical systems with time-delay are derived. Some analytical methods and a type of Lyapunov functional are used to investigate such sufficient conditions. The results obtained in this paper are applicable to perturbed time-delay systems with unbounded time-varying delay.Some previous results are improved and a numerical example is given to demonstrate the validity of our results.

  11. Global dynamics behaviors for new delay SEIR epidemic disease model with vertical transmission and pulse vaccination

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A robust SEIR epidemic disease model with a profitless delay and vertical transmission is formulated, and the dynamics behaviors of the model under pulse vaccination are analyzed.By use of the discrete dynamical system determined by the the model are under appropriate conditions.Using the theory on delay functional and impulsive differential equation, the sufficient condition with time delay for the permanence of the system is obtained, and it is proved that time delays, pulse vaccination and vertical transmission can bring obvious effects on the dynamics behaviors of the model.

  12. Time-domain nature of group delay

    Institute of Scientific and Technical Information of China (English)

    王建武; 冯正和

    2015-01-01

    The characteristic of group delay is analyzed based on an electronic circuit, and its time-domain nature is studied with time-domain simulation and experiment. The time-domain simulations and experimental results show that group delay is the delay of the energy center of the amplitude-modulated pulse, rather than the propagation delay of the electromagnetic field. As group velocity originates from the definition of group delay and group delay is different from the propagation delay, the superluminality or negativity of group velocity does not mean the superluminal or negative propagation of the electromagnetic field.

  13. Mathematical analysis of a nutrient-plankton system with delay.

    Science.gov (United States)

    Rehim, Mehbuba; Zhang, Zhenzhen; Muhammadhaji, Ahmadjan

    2016-01-01

    A mathematical model describing the interaction of nutrient-plankton is investigated in this paper. In order to account for the time needed by the phytoplankton to mature after which they can release toxins, a discrete time delay is incorporated into the system. Moreover, it is also taken into account discrete time delays which indicates the partially recycled nutrient decomposed by bacteria after the death of biomass. In the first part of our analysis the sufficient conditions ensuring local and global asymptotic stability of the model are obtained. Next, the existence of the Hopf bifurcation as time delay crosses a threshold value is established and, meanwhile, the phenomenon of stability switches is found under certain conditions. Numerical simulations are presented to illustrate the analytical results.

  14. Schwarz waveform relaxation algorithm for heat equations with distributed delay

    Directory of Open Access Journals (Sweden)

    Wu Shu-Lin

    2016-01-01

    Full Text Available Heat equations with distributed delay are a class of mathematic models that has wide applications in many fields. Numerical computation plays an important role in the investigation of these equations, because the analytic solutions of partial differential equations with time delay are usually unavailable. On the other hand, duo to the delay property, numerical computation of these equations is time-consuming. To reduce the computation time, we analyze in this paper the Schwarz waveform relaxation algorithm with Robin transmission conditions. The Robin transmission conditions contain a free parameter, which has a significant effect on the convergence rate of the Schwarz waveform relaxation algorithm. Determining the Robin parameter is therefore one of the top-priority matters for the study of the Schwarz waveform relaxation algorithm. We provide new formula to fix the Robin parameter and we show numerically that the new Robin parameter is more efficient than the one proposed previously in the literature.

  15. Dynamical analysis of uncertain neural networks with multiple time delays

    Science.gov (United States)

    Arik, Sabri

    2016-02-01

    This paper investigates the robust stability problem for dynamical neural networks in the presence of time delays and norm-bounded parameter uncertainties with respect to the class of non-decreasing, non-linear activation functions. By employing the Lyapunov stability and homeomorphism mapping theorems together, a new delay-independent sufficient condition is obtained for the existence, uniqueness and global asymptotic stability of the equilibrium point for the delayed uncertain neural networks. The condition obtained for robust stability establishes a matrix-norm relationship between the network parameters of the neural system, which can be easily verified by using properties of the class of the positive definite matrices. Some constructive numerical examples are presented to show the applicability of the obtained result and its advantages over the previously published corresponding literature results.

  16. Patient ignorance is the main reason for treatment delay in primary rhegmatogenous retinal detachment in The Netherlands

    NARCIS (Netherlands)

    Goezinne, F.; Heij, La E.C.; Berendschot, T.; Tahzib, N.G.; Koetsier, L.S.; Hoevenaars, J.; Liem, A.T.A.; Kijlstra, A.; Webers, C.A.B.; Hendrikse, F.

    2009-01-01

    Aims Treatment delay of progressive vision-threatening conditions should be minimal. In this study, the treatment delay of patients with a rhegmatogenous retinal detachment (RRD) undergoing retinal detachment surgery was quantified, and causes for this delay were evaluated. Materials and methods Con

  17. The Oscillation of a Class of the Fractional-Order Delay Differential Equations

    Directory of Open Access Journals (Sweden)

    Qianli Lu

    2014-01-01

    Full Text Available Several oscillation results are proposed including necessary and sufficient conditions for the oscillation of fractional-order delay differential equations with constant coefficients, the sufficient or necessary and sufficient conditions for the oscillation of fractional-order delay differential equations by analysis method, and the sufficient or necessary and sufficient conditions for the oscillation of delay partial differential equation with three different boundary conditions. For this, α-exponential function which is a kind of functions that play the same role of the classical exponential functions of fractional-order derivatives is used.

  18. Diagnostic Delay in Rheumatoid Arthritis

    DEFF Research Database (Denmark)

    Mølbaek, Karen; Hørslev-Petersen, Kim; Primdahl, Jette

    2016-01-01

    BACKGROUND: To prevent joint damage among patients with rheumatoid arthritis (RA), there is a need to minimize delays from the onset of symptoms until the initiation of appropriate therapy. The present study explored the factors that have an impact on the time it takes for Danish patients with RA...

  19. Livermore blasted for project delay

    CERN Multimedia

    1999-01-01

    In a 12 page report issued last week, a review committee set up by the University of California has concluded that mismanagement and poor planning are to blame for significant cost overruns and delays in the construction of NIF, the worlds largest laser (1 page).

  20. Providing delay guarantees in Bluetooth

    NARCIS (Netherlands)

    Ait Yaiz, R.; Heijenk, Gerhard J.; Titsworth, F.

    2003-01-01

    Bluetooth polling, also referred to as Bluetooth MAC scheduling or intra-piconet scheduling, is the mechanism that schedules the traffic between the participants in a Bluetooth network. Hence, this mechanism is highly determining with respect to the delay packets experience in a Bluetooth network.

  1. Deconstructing delayed posttraumatic stress disorder

    NARCIS (Netherlands)

    Smid, G.E.

    2011-01-01

    According to the Diagnostic and Statistical Manual of Mental Disorders, delayed posttraumatic stress disorder (PTSD) must be diagnosed in individuals fulfilling criteria for PTSD if the onset of symptoms is at least six months after the trauma. The purpose of this thesis was to establish the prevale

  2. Advanced optical delay line demonstrator

    NARCIS (Netherlands)

    Dool, T.C. van den; Kamphues, F.G.; Fouss, B.; Henrioulle, K.; Hogenhuis, H.

    2004-01-01

    TNO TPD, in cooperation with Micromega-Dynamics and Dutch Space, has designed an advanced Optical Delay Line (ODL) for use in future ground based and space interferometry missions. The work is performed under NIVR contract in preparation for GENIE and DARWIN. Using the ESO PRIMA DDL requirements as

  3. Providing Delay Guarantees in Bluetooth

    NARCIS (Netherlands)

    Ait Yaiz, Rachid; Heijenk, Geert; Titsworth, F.

    2003-01-01

    Bluetooth polling, also referred to as Bluetooth MAC scheduling or intra-piconet scheduling, is the mechanism that schedules the traffic between the participants in a Bluetooth network. Hence, this mechanism is highly determining with respect to the delay packets experience in a Bluetooth network. I

  4. Learning monopolies with delayed feedback on price expectations

    Science.gov (United States)

    Matsumoto, Akio; Szidarovszky, Ferenc

    2015-11-01

    We call the intercept of the price function with the vertical axis the maximum price and the slope of the price function the marginal price. In this paper it is assumed that a monopolistic firm has full information about the marginal price and its own cost function but is uncertain on the maximum price. However, by repeated interaction with the market, the obtained price observations give a basis for an adaptive learning process of the maximum price. It is also assumed that the price observations have fixed delays, so the learning process can be described by a delayed differential equation. In the cases of one or two delays, the asymptotic behavior of the resulting dynamic process is examined, stability conditions are derived. Three main results are demonstrated in the two delay learning processes. First, it is possible to stabilize the equilibrium which is unstable in the one delay model. Second, complex dynamics involving chaos, which is impossible in the one delay model, can emerge. Third, alternations of stability and instability (i.e., stability switches) occur repeatedly.

  5. Time Delay Circuits: A Quality Criterion for Delay Variations versus Frequency

    NARCIS (Netherlands)

    Garakoui, Seyed Kasra; Klumperink, Eric A.M.; Nauta, Bram; Vliet, van Frank E.

    2010-01-01

    This paper shows that the group delay of a delay circuit does not give sufficient information to predict the delay vs. frequency. A new criterion (fϕ=0) is proposed that characterizes the delay variations over a specified frequency range. The mathematical derivation of fϕ=0 for a single delay block

  6. THE ALL-DELAY STABILITY OF DEGENERATE DIFFERENTIAL SYSTEMS WITH DELAY

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In this paper,the all-delay stability of degenerate differential systems with delay is discussed.We come up with some new criteria for evaluating the all-delay stability of degenerate differential systems with delay and degenerate neutral differential systems with delay.Also,we give an example to illustrate the main results.

  7. Visual discrimination of delayed self-generated movement reveals the temporal limit of proprioceptive-visual intermodal integration.

    Science.gov (United States)

    Jaime, Mark; O'Driscoll, Kelly; Moore, Chris

    2016-07-01

    This study examined the intermodal integration of visual-proprioceptive feedback via a novel visual discrimination task of delayed self-generated movement. Participants performed a goal-oriented task in which visual feedback was available only via delayed videos displayed on two monitors-each with different delay durations. During task performance, delay duration was varied for one of the videos in the pair relative to a standard delay, which was held constant. Participants were required to identify and use the video with the lesser delay to perform the task. Visual discrimination of the lesser-delayed video was examined under four conditions in which the standard delay was increased for each condition. A temporal limit for proprioceptive-visual intermodal integration of 3-5s was revealed by subjects' inability to reliably discriminate video pairs.

  8. Conditioned Inhibition in a Rodent Model of Attention-Deficit/Hyperactivity Disorder

    Science.gov (United States)

    Green, John T.; Chess, Amy C.; Conquest, Cynthia J.; Yegla, Brittney A.

    2011-01-01

    A deficit in inhibition may underlie some of the symptoms of Attention-deficit/hyperactivity disorder (ADHD), particularly impulsivity. However, the data on inhibitory deficits in children with ADHD are mixed. Moreover, there has been little characterization of inhibitory processes in animal models of ADHD. Pavlov’s conditioned inhibition procedure allows a direct assessment of the inhibitory status of a stimulus via summation and retardation tests. Therefore, in the current study we examined conditioned inhibition in spontaneously hypertensive rats (SHRs), the most well-validated animal model of ADHD. SHRs and Wistar rats were trained in a simultaneous feature-negative discrimination in eyeblink conditioning. Each session consisted of a mixture of two trial types: a tone paired with a periocular stimulation (A+) or a tone and light presented simultaneously without a periocular stimulation (XA−). Both SHRs and Wistars were able to discriminate A+ from XA− trials. In subsequent summation (X presented simultaneously with a different conditioned excitor, B) and retardation (X paired with the periocular stimulation) tests, the presence of inhibition to X was confirmed in both SHRs and Wistars: X reduced responding to B and X was slow to develop excitation when paired with periocular stimulation. These results are the first to demonstrate Pavlovian conditioned inhibition in SHRs and to use a summation and a retardation test to confirm X as a conditioned inhibitor. The data indicate that conditioned inhibition is intact in SHRs, thus inhibitory processes that do not require prefrontal cortex or cerebellum may be normal in this strain. PMID:22004263

  9. Stability of a delayed predator—prey model in a random environment

    Science.gov (United States)

    Jin, Yan-Fei; Xie, Wen-Xian

    2015-11-01

    The stability of the first-order and second-order solution moments for a Harrison-type predator-prey model with parametric Gaussian white noise is analyzed in this paper. The moment equations of the system solution are obtained under Itô interpretations. The delay-independent stable condition of the first-order moment is identical to that of the deterministic delayed system, and the delay-independent stable condition of the second-order moment depends on the noise intensities. The corresponding critical time delays are determined once the stabilities of moments lose. Further, when the time delays are greater than the critical time delays, the system solution becomes unstable with the increase of noise intensities. Finally, some numerical simulations are given to verify the theoretical results. Project supported by the National Natural Science Foundation of China (Grant Nos. 11272051 and 11302172).

  10. Stability of a delayed predator prey model in a random environment

    Institute of Scientific and Technical Information of China (English)

    靳艳飞; 谢文贤

    2015-01-01

    The stability of the first-order and second-order solution moments for a Harrison-type predator–prey model with parametric Gaussian white noise is analyzed in this paper. The moment equations of the system solution are obtained under Itˆo interpretations. The delay-independent stable condition of the first-order moment is identical to that of the deterministic delayed system, and the delay-independent stable condition of the second-order moment depends on the noise intensities. The corresponding critical time delays are determined once the stabilities of moments lose. Further, when the time delays are greater than the critical time delays, the system solution becomes unstable with the increase of noise intensities. Finally, some numerical simulations are given to verify the theoretical results.

  11. Delay Estimates of Mixed Traffic Flow at Signalized Intersections in China

    Institute of Scientific and Technical Information of China (English)

    SU Yuelong; WEI Zheng; CHENG Sihan; YAO Danya; ZHANG Yi; LI Li

    2009-01-01

    Two characteristics of Chinese mixed traffic invalidate the conventional queuing delay estimates for western countries. First, the driving characteristics of Chinese drivers lead to different delays even though the other conditions are the same. Second, urban traffic flow in China is often hindered by pedestrians at intersections, such that imported intelligent traffic control systems do not work appropriately. Typical delay estimates for Chinese conditions were obtained from data for over 500 vehicle queues in Beijing collected using charge coupled device (CCD) cameras. The results show that the delays mainly depend on the pro-portion and positions of heavy vehicles in the queue, as well as the start-up situations (with or without inter-ference). A simplified delay estimation model considers vehicle types and positions that compares well with the observed traffic delays.

  12. Delay Tolerant Network Routing Nature – A Study

    Directory of Open Access Journals (Sweden)

    V. Prema Tulasi

    2014-04-01

    Full Text Available Delay-Tolerant network (DTN is a network in which no simultaneous end-to-end path exists. And the messages delivered in the DTN usually have large delivery latency due to network partition. These special characteristics make DTN routing a challenging problem. For this purpose, we updated the shortest path based routing algorithms using conditional intermeeting times and proposed to route the messages over conditional shortest paths. This proposes Conditional Shortest Path Routing (CSPR protocol that route the messages over conditional shortest paths in which the cost of links between nodes is defined by conditional intermeeting times rather than the conventional intermeeting times.

  13. Conical-Domain Model for Estimating GPS Ionospheric Delays

    Science.gov (United States)

    Sparks, Lawrence; Komjathy, Attila; Mannucci, Anthony

    2009-01-01

    -latitudes under disturbed conditions, the accuracy of SBAS systems based upon the thin-shell model suffers due to the presence of complex ionospheric structure, high delay values, and large electron density gradients. Interpolation on the vertical delay grid serves as an additional source of delay error. The conical-domain model permits direct computation of the user s slant delay estimate without the intervening use of a vertical delay grid. The key is to restrict each fit of GPS measurements to a spatial domain encompassing signals from only one satellite. The conical domain model is so named because each fit involves a group of GPS receivers that all receive signals from the same GPS satellite (see figure); the receiver and satellite positions define a cone, the satellite position being the vertex. A user within a given cone evaluates the delay to the satellite directly, using (1) the IPP coordinates of the line of sight to the satellite and (2) broadcast fit parameters associated with the cone. The conical-domain model partly resembles the thin-shell model in that both models reduce an inherently four-dimensional problem to two dimensions. However, unlike the thin-shell model, the conical domain model does not involve any potentially erroneous simplifying assumptions about the structure of the ionosphere. In the conical domain model, the initially four-dimensional problem becomes truly two-dimensional in the sense that once a satellite location has been specified, any signal path emanating from a satellite can be identified by only two coordinates; for example, the IPP coordinates. As a consequence, a user s slant-delay estimate converges to the correct value in the limit that the receivers converge to the user s location (or, equivalently, in the limit that the measurement IPPs converge to the user s IPP).

  14. "DETERMINANTS OF PREHOSPITAL DELAY IN PATIENTS WITH ACUTE MYOCARDIAL INFARCTION"

    Directory of Open Access Journals (Sweden)

    M. Alidoosti

    2004-05-01

    Full Text Available Determination of pre-hospital delay time of patients with acute myocardial infarction and seeking ways of speeding up the time for reperfusion is an important factor to lower mortality in these patients. This is a cross-sectional study to determine pre-hospital delay time, its components, and related causes and conditions, obtained in 375 patients with prolonged chest pain referred to four hospitals of Tehran University of Medical Sciences. Means of transport to hospital, reasons of ambulance disuse, decision time by the patient and finally the entire time of pre-hospital delay were specified. Suspected factors related to delays of more than 2 and 6 h were scrutinized with chi-square test. Rate of ambulance utility (18.9% directly correlated with age of patients (P<0.05. Principal motives to disuse ambulance insuccession were unrememberance (33.7%, access to private vehicle (32.8% and supposition of sufficient speed of personal reference (18.9%. Pre-hospital delay time was 8.1 ± 9.1 h (mean ± SD in whole patients and 7.6 ± 9.1 h in those with acute myocardial infarction. Delays of more than 2 and 6 hoccurred in 67.5% and 33.6% of patients, respectively. Decision time constitute three fourth of whole pre-hospital delay and was correlated with female gender, older age, history of diabetes, lower level of literacy and nocturnal onset of symptoms. In conclusion, a significant number of patients with acute myocardial infarction have pre-hospital delay of more than 2 and even 6 h, when golden time for thrombolytic therapy has already been elapsed.

  15. Comment on "Generalized projective synchronization in time-delayed systems: nonlinear observer approach" [Chaos 19, 013102 (2009); 20, 029902 (2010)].

    Science.gov (United States)

    Theesar, S Jeeva Sathya; Balasubramaniam, P; Banerjee, Santo

    2012-09-01

    In Chaos 19, 013102 (2009), the author proposed generalized projective synchronization for time delay systems using nonlinear observer and obtained sufficient condition to ensure projective synchronization for modulated time varying delay. There are concerns with the obtained conditions as the result was applicable only to trivial case of time varying delay τ[over dot](1)(t)=dτ(1)(t)/dt<1. In this paper, we note the drawbacks of the proposed sufficient condition. The new improved sufficient condition for ensuring the projective synchronization of time varying delayed systems is presented. The proposed new criteria have been verified by adopting the Ikeda system.

  16. Discrete-Time Sliding Mode Control for Uncertain Networked System Subject to Time Delay

    Directory of Open Access Journals (Sweden)

    Saulo C. Garcia

    2015-01-01

    Full Text Available We deal with uncertain systems with networked sliding mode control, subject to time delay. To minimize the degenerative effects of the time delay, a simpler format of state predictor is proposed in the control law. Some ultimate bounded stability analyses and stabilization conditions are provided for the uncertain time delay system with proposed discrete-time sliding mode control strategy. A numerical example is presented to corroborate the analyses.

  17. OSCILLATORY PROPERTIES OF THE SOLUTIONS OF NONLINEAR DELAY HYPERBOLIC DIFFERENTIAL EQUATIONS OF NEUTRAL TYPE

    Institute of Scientific and Technical Information of China (English)

    刘安平; 何猛省

    2002-01-01

    By making use of the integral inequalities and some results of the functional differential equations, oscillatory properties of solutions of certain nonlinear hyperbolic partial differential equations of neutral type with multi-delays were investigated and a series of sufficient conditions for oscillations of the equations were established. The results fully indicate that the oscillations are caused by delay and hence reveal the difference between these equations and those equations without delay.

  18. Global exponential stabilisation of a class of nonlinear time-delay systems

    Science.gov (United States)

    Benabdallah, Amel; Echi, Nadhem

    2016-12-01

    This paper deals with the state and output feedback stabilisation problems for a family of nonlinear time-delay systems satisfying some relaxed triangular-type condition. The delay is supposed to be constant. Parameter-dependent control laws are used to compensate for the nonlinearities. Based on the Lyapunov-Krasovskii functionals, global exponential stability of the closed-loop systems is achieved. Finally, an extension to nonlinear time-varying delay systems is given.

  19. Synchronization of Different Fractional Order Time-Delay Chaotic Systems Using Active Control

    Directory of Open Access Journals (Sweden)

    Jianeng Tang

    2014-01-01

    Full Text Available Chaos synchronization of different fractional order time-delay chaotic systems is considered. Based on the Laplace transform theory, the conditions for achieving synchronization of different fractional order time-delay chaotic systems are analyzed by use of active control technique. Then numerical simulations are provided to verify the effectiveness and feasibility of the developed method. At last, effects of the fraction order and the time delay on synchronization are further researched.

  20. Compensation for time-delayed feedback bang-bang control of quasi-integrable Hamiltonian systems

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The stochastic averaging method for quasi-integrable Hamiltonian systems with time-delayed feedback bang-bang control is first introduced. Then, two time delay compensation methods, namely the method of changing control force amplitude (CFA) and the method of changing control delay time (CDT), are proposed. The conditions applicable to each compensation method are discussed. Finally, an example is worked out in detail to illustrate the application and effectiveness of the proposed methods and the two compensation methods in combination.

  1. Stability Analysis for Fractional-Order Linear Singular Delay Differential Systems

    Directory of Open Access Journals (Sweden)

    Hai Zhang

    2014-01-01

    Full Text Available We investigate the delay-independently asymptotic stability of fractional-order linear singular delay differential systems. Based on the algebraic approach, the sufficient conditions are presented to ensure the asymptotic stability for any delay parameter. By applying the stability criteria, one can avoid solving the roots of transcendental equations. An example is also provided to illustrate the effectiveness and applicability of the theoretical results.

  2. Dynamical Consensus Algorithm for Second-Order Multi-Agent Systems Subjected to Communication Delay

    Institute of Scientific and Technical Information of China (English)

    LIU Cheng-Lin; LIU Fei

    2013-01-01

    To solve the dynamical consensus problem of second-order multi-agent systems with communication delay,delay-dependent compensations are added into the normal asynchronously-coupled consensus algorithm so as to make the agents achieve a dynamical consensus.Based on frequency-domain analysis,sufficient conditions are gained for second-order multi-agent systems with communication delay under leaderless and leader-following consensus algorithms respectively.Simulation illustrates the correctness of the results.

  3. Guaranteed cost control for uncertain stochastic fuzzy systems with time delay

    Institute of Scientific and Technical Information of China (English)

    ZHANG Huaguang; WANG Yingchun

    2007-01-01

    This paper studies a delay-dependent guaranteed cost control problem for a class of uncertain nonlinear stochastic systems with time delay represented by the Takagi-Sugeno (T-S) fuzzy model with uncertain parameters. The descriptor system method and Gu's inequality are employed to obtain delay-dependent sufficient conditions such that the closed-loop system is asymptotically stable with a certain guaranteed cost control performance. The effectiveness of the proposed method is shown by a simulation example.

  4. Global Exponential Stability of Discrete-Time Neural Networks with Time-Varying Delays

    Directory of Open Access Journals (Sweden)

    S. Udpin

    2013-01-01

    Full Text Available This paper presents some global stability criteria of discrete-time neural networks with time-varying delays. Based on a discrete-type inequality, a new global stability condition for nonlinear difference equation is derived. We consider nonlinear discrete systems with time-varying delays and independence of delay time. Numerical examples are given to illustrate the effectiveness of our theoretical results.

  5. Synchronization of Different Fractional Order Time-Delay Chaotic Systems Using Active Control

    OpenAIRE

    Jianeng Tang

    2014-01-01

    Chaos synchronization of different fractional order time-delay chaotic systems is considered. Based on the Laplace transform theory, the conditions for achieving synchronization of different fractional order time-delay chaotic systems are analyzed by use of active control technique. Then numerical simulations are provided to verify the effectiveness and feasibility of the developed method. At last, effects of the fraction order and the time delay on synchronization are further researched.

  6. A Sliding Mode Control for Uncertain Time-delay Systems

    Institute of Scientific and Technical Information of China (English)

    WU Jun-sheng; WENG Zheng-xin; TIAN Zuo-hua; SHI Song-jiao

    2008-01-01

    By means of the feasibility of some linear matrix inequalities (LMIs), delay dependeat sufficient condition is derived for the existence of a linear sliding surface, which guarantees quadratic stability of the reduced-order equivalent system restricted to the sliding surface. And a reaching motion controller is proposed. A numerical simulation shows the effectiveness of the approach.

  7. Stabilizing control for a class of delay unstable processes.

    Science.gov (United States)

    Lee, See Chek; Wang, Qing-Guo; Nguyen, Le Binh

    2010-07-01

    The stabilization of unstable first-order plus time-delay processes with a zero by means of simple controllers is investigated in detail. Explicit stabilizability conditions are established. And the computational methods for determining stabilizing controller parameters are also presented with illustrative examples.

  8. ALMOST PERIODICITY FOR AN IMPULSIVE PURE DELAY LOGISTIC EQUATION

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    By employing a fixed point theorem in cones,we investigate the existence of almost periodic solutions to an impulsive pure delay Logistic equation. A set of suffcient conditions for the existence of almost periodic solutions to the equation are obtained.

  9. Absolute Stability of Discrete-Time Systems with Delay

    Directory of Open Access Journals (Sweden)

    Medina Rigoberto

    2008-01-01

    Full Text Available We investigate the stability of nonlinear nonautonomous discrete-time systems with delaying arguments, whose linear part has slowly varying coefficients, and the nonlinear part has linear majorants. Based on the "freezing" technique to discrete-time systems, we derive explicit conditions for the absolute stability of the zero solution of such systems.

  10. Razumikhin's method in the qualitative theory of processes with delay

    Directory of Open Access Journals (Sweden)

    Anatoly D. Myshkis

    1995-01-01

    Full Text Available B.S. Razumikhin's concept in the qualitative theory of systems delay is clarified and discussed. Various ways of improvements of stability conditions are considered. The author shows that the guiding role of Lyapunov functions and demonstrates Razumikhin's method as a practical case of continuous version of the mathematical induction. Several examples demonstrate the obtained results.

  11. Finite-Time Stability of Nonautonomous Delayed Systems

    Institute of Scientific and Technical Information of China (English)

    孙武军; 孔德兴

    2003-01-01

    The finite-time stability to linear discontinuous time-varying delayed system was investigated. By applying the method of upper and lower solutions, some sufficient conditions of this kind of stability were obtained.Furthermore, it also developed a monotone iterative technique for obtaining solutions which are obtained as limits of monotone sequences

  12. Boundary-Value Problems for Weakly Nonlinear Delay Differential Systems

    Directory of Open Access Journals (Sweden)

    A. Boichuk

    2011-01-01

    Full Text Available Conditions are derived of the existence of solutions of nonlinear boundary-value problems for systems of n ordinary differential equations with constant coefficients and single delay (in the linear part and with a finite number of measurable delays of argument in nonlinearity: ż(t=Az(t-τ+g(t+εZ(z(hi(t,t,ε,  t∈[a,b], assuming that these solutions satisfy the initial and boundary conditions z(s:=ψ(s if s∉[a,b],  lz(⋅=α∈Rm. The use of a delayed matrix exponential and a method of pseudoinverse by Moore-Penrose matrices led to an explicit and analytical form of sufficient conditions for the existence of solutions in a given space and, moreover, to the construction of an iterative process for finding the solutions of such problems in a general case when the number of boundary conditions (defined by a linear vector functional l does not coincide with the number of unknowns in the differential system with a single delay.

  13. Chaotifying delayed recurrent neural networks via impulsive effects

    Science.gov (United States)

    Şaylı, Mustafa; Yılmaz, Enes

    2016-02-01

    In this paper, chaotification of delayed recurrent neural networks via chaotically changing moments of impulsive actions is considered. Sufficient conditions for the presence of Li-Yorke chaos with its ingredients proximality, frequent separation, and existence of infinitely many periodic solutions are theoretically proved. Finally, effectiveness of our theoretical results is illustrated by an example with numerical simulations.

  14. STABILITY OF STOCHASTIC DIFFERENTIAL EQUATIONS WITH UNBOUNDED DELAY

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In this paper,we obtain suffcient conditions for the stability in p-th moment of the analytical solutions and the mean square stability of a stochastic differential equation with unbounded delay proposed in [6,10] using the explicit Euler method.

  15. Fundamentals of Delayed Coking Joint Industry Project

    Energy Technology Data Exchange (ETDEWEB)

    Michael Volk Jr; Keith Wisecarver

    2005-10-01

    is 2,937,439 barrels/calendar day. These cokers produce 154,607 tons of coke per day and delayed coking accounts for 88% of the world capacity. The delayed coking charge capacity in the United States is 1,787,860 b/cd. Despite its wide commercial use, only relatively few contractors and refiners are truly knowledgeable in delayed-coking design, so that this process carries with it a ''black art'' connotation. Until recently, the expected yield from cokers was determined by a simple laboratory test on the feedstock. As a result of Tulsa University's prior related research, a process model was developed that with additional work could be used to optimize existing delayed cokers over a wide range of potential feedstocks and operating conditions. The objectives of this research program are to: utilize the current micro, batch and pilot unit facilities at The University of Tulsa to enhance the understanding of the coking process; conduct additional micro and pilot unit tests with new and in-house resids and recycles to make current optimization models more robust; conduct focused kinetic experiments to enhance the furnace tube model and to enhance liquid production while minimizing sulfur in the products; conduct detailed foaming studies to optimize the process and minimize process upsets; quantify the parameters that affect coke morphology; and to utilize the knowledge gained from the experimental and modeling studies to enhance the computer programs developed in the previous JIP for optimization of the coking process. These refined computer models will then be tested against refinery data provided by the member companies. Novel concepts will also be explored for hydrogen sulfide removal of furnace gases as well as gas injection studies to reduce over-cracking. The following deliverables are scheduled from the two projects of the three-year JIP: (1) A novel method for enhancing liquid yields from delayed cokers and data that provide insight as to

  16. New Stability Criteria for High-Order Neural Networks with Proportional Delays

    Science.gov (United States)

    Xu, Chang-Jin; Li, Pei-Luan

    2017-03-01

    This paper is concerned with high-order neural networks with proportional delays. The proportional delay is a time-varying unbounded delay which is different from the constant delay, bounded time-varying delay and distributed delay. By the nonlinear transformation {y}i(t)={u}i({{{e}}}t){{ }}(i=1,2,\\ldots ,n), we transform a class of high-order neural networks with proportional delays into a class of high-order neural networks with constant delays and time-varying coefficients. With the aid of Brouwer fixed point theorem and constructing the delay differential inequality, we obtain some delay-independent and delay-dependent sufficient conditions to ensure the existence, uniqueness and global exponential stability of equilibrium of the network. Two examples with their simulations are given to illustrate the theoretical findings. Our results are new and complement previously known results. Supported by National Natural Science Foundation of China under Grant Nos. 61673008 and 11261010, and Project of High-level Innovative Talents of Guizhou Province ([2016]5651)

  17. Dramatic robustness of a multiple delay dispersed interferometer to spectrograph errors: how mixing delays reduces or cancels wavelength drift

    Science.gov (United States)

    Erskine, David J.; Linder, E.; Wishnow, E.; Edelstein, J.; Sirk, M.; Muirhead, P.; Lloyd, J.; Kim, A.

    2016-08-01

    We describe demonstrations of remarkable robustness to instrumental noises by using a multiple delay externally dispersed interferometer (EDI) on stellar observations at the Hale telescope. Previous observatory EDI demonstrations used a single delay. The EDI (also called "TEDI") boosted the 2,700 resolution of the native TripleSpec NIR spectrograph (950-2450 nm) by as much as 10x to 27,000, using 7 overlapping delays up to 3 cm. We observed superb rejection of fixed pattern noises due to bad pixels, since the fringing signal responds only to changes in multiple exposures synchronous to the applied delay dithering. Remarkably, we observed a 20x reduction of reaction in the output spectrum to PSF shifts of the native spectrograph along the dispersion direction, using our standard processing. This allowed high resolution observations under conditions of severe and irregular PSF drift otherwise not possible without the interferometer. Furthermore, we recently discovered an improved method of weighting and mixing data between pairs of delays that can theoretically further reduce the net reaction to PSF drift to zero. We demonstrate a 350x reduction in reaction to a native PSF shift using a simple simulation. This technique could similarly reduce radial velocity noise for future EDI's that use two delays overlapped in delay space (or a single delay overlapping the native peak). Finally, we show an extremely high dynamic range EDI measurement of our ThAr lamp compared to a literature ThAr spectrum, observing weak features ( 0.001x height of nearest strong line) that occur between the major lines. Because of individuality of each reference lamp, accurate knowledge of its spectrum between the (unfortunately) sparse major lines is important for precision radial velocimetry.

  18. Delay of Vehicle Motion in Traffic Dynamics

    CERN Document Server

    Bando, M; Nakanishi, K; Nakayama, A; Bando, Masako; Hasebe, Katsuya; Nakanishi, Ken; Nakayama, Akihiro

    1996-01-01

    We demonstrate that in Optimal Velocity Model (OVM) delay times of vehicles coming from the dynamical equation of motion of OVM almost explain the order of delay times observed in actual traffic flows without introducing explicit delay times. Delay times in various cases are estimated: the case of a leader vehicle and its follower, a queue of vehicles controlled by traffic lights and many-vehicle case of highway traffic flow. The remarkable result is that in most of the situation for which we can make a reasonable definition of a delay time, the obtained delay time is of order 1 second.

  19. Robust Moving Horizon H∞ Control of Discrete Time-Delayed Systems with Interval Time-Varying Delays

    Directory of Open Access Journals (Sweden)

    F. Yıldız Tascikaraoglu

    2014-01-01

    Full Text Available In this study, design of a delay-dependent type moving horizon state-feedback control (MHHC is considered for a class of linear discrete-time system subject to time-varying state delays, norm-bounded uncertainties, and disturbances with bounded energies. The closed-loop robust stability and robust performance problems are considered to overcome the instability and poor disturbance rejection performance due to the existence of parametric uncertainties and time-delay appeared in the system dynamics. Utilizing a discrete-time Lyapunov-Krasovskii functional, some delay-dependent linear matrix inequality (LMI based conditions are provided. It is shown that if one can find a feasible solution set for these LMI conditions iteratively at each step of run-time, then we can construct a control law which guarantees the closed-loop asymptotic stability, maximum disturbance rejection performance, and closed-loop dissipativity in view of the actuator limitations. Two numerical examples with simulations on a nominal and uncertain discrete-time, time-delayed systems, are presented at the end, in order to demonstrate the efficiency of the proposed method.

  20. Delay locked loop integrated circuit.

    Energy Technology Data Exchange (ETDEWEB)

    Brocato, Robert Wesley

    2007-10-01

    This report gives a description of the development of a Delay Locked Loop (DLL) integrated circuit (IC). The DLL was developed and tested as a stand-alone IC test chip to be integrated into a larger application specific integrated circuit (ASIC), the Quadrature Digital Waveform Synthesizer (QDWS). The purpose of the DLL is to provide a digitally programmable delay to enable synchronization between an internal system clock and external peripherals with unknown clock skew. The DLL was designed and fabricated in the IBM 8RF process, a 0.13 {micro}m CMOS process. It was designed to operate with a 300MHz clock and has been tested up to 500MHz.