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Sample records for interval intracortical inhibition

  1. The effects of transcranial direct current stimulation on short-interval intracortical inhibition and intracortical facilitation: a systematic review and meta-analysis.

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    Biabani, Mana; Aminitehrani, Maryam; Zoghi, Maryam; Farrell, Michael; Egan, Gary; Jaberzadeh, Shapour

    2018-01-26

    Transcranial direct current stimulation (tDCS) is increasingly being used to affect the neurological conditions with deficient intracortical synaptic activities (i.e. Parkinson's disease and epilepsy). In addition, it is suggested that the lasting effects of tDCS on corticospinal excitability (CSE) have intracortical origin. This systematic review and meta-analysis aimed to examine whether tDCS has any effect on intracortical circuits. Eleven electronic databases were searched for the studies investigating intracortical changes induced by anodal (a) and cathodal (c) tDCS, in healthy individuals, using two paired-pulse transcranial magnetic stimulation (TMS) paradigms: short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF). Additionally, motor-evoked potential (MEP) size alterations, assessed by single-pulse TMS, were extracted from these studies to investigate the probable intracortical origin of tDCS effects on CSE. The methodological quality of included studies was examined using Physiotherapy Evidence Database (PEDro) and Downs and Black's (D&B) assessment tools. Thirteen research papers, including 24 experiments, were included in this study scoring good and medium quality in PEDro and D&B scales, respectively. Immediately following anodal tDCS (a-tDCS) applications, we found significant decreases in SICI, but increases in ICF and MEP size. However, ICF and MEP size significantly decreased, and SICI increased immediately following cathodal tDCS (c-tDCS). The results of this systematic review and meta-analysis reveal that a-tDCS changes intracortical activities (SICI and ICF) toward facilitation, whereas c-tDCS alters them toward inhibition. It can also be concluded that increases and decreases in CSE after tDCS application are associated with corresponding changes in intracortical activities. The results suggest that tDCS can be clinically useful to modulate intracortical circuits.

  2. Proactive modulation of long-interval intracortical inhibition during response inhibition

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    Cowie, Matthew J.; MacDonald, Hayley J.; Cirillo, John

    2016-01-01

    Daily activities often require sudden cancellation of preplanned movement, termed response inhibition. When only a subcomponent of a whole response must be suppressed (required here on Partial trials), the ensuing component is markedly delayed. The neural mechanisms underlying partial response inhibition remain unclear. We hypothesized that Partial trials would be associated with nonselective corticomotor suppression and that GABAB receptor-mediated inhibition within primary motor cortex might be responsible for the nonselective corticomotor suppression contributing to Partial trial response delays. Sixteen right-handed participants performed a bimanual anticipatory response inhibition task while single- and paired-pulse transcranial magnetic stimulation was delivered to elicit motor evoked potentials in the left first dorsal interosseous muscle. Lift times, amplitude of motor evoked potentials, and long-interval intracortical inhibition were examined across the different trial types (Go, Stop-Left, Stop-Right, Stop-Both). Go trials produced a tight distribution of lift times around the target, whereas those during Partial trials (Stop-Left and Stop-Right) were substantially delayed. The modulation of motor evoked potential amplitude during Stop-Right trials reflected anticipation, suppression, and subsequent reinitiation of movement. Importantly, suppression was present across all Stop trial types, indicative of a “default” nonselective inhibitory process. Compared with blocks containing only Go trials, inhibition increased when Stop trials were introduced but did not differ between trial types. The amount of inhibition was positively correlated with lift times during Stop-Right trials. Tonic levels of inhibition appear to be proactively modulated by task context and influence the speed at which unimanual responses occur after a nonselective “brake” is applied. PMID:27281744

  3. Paired-Pulse TMS and Fine-Wire Recordings Reveal Short-Interval Intracortical Inhibition and Facilitation of Deep Multifidus Muscle Fascicles.

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    Hugo Massé-Alarie

    Full Text Available Paired-pulse transcranial magnetic stimulation (ppTMS is used to probe inhibitory and excitatory networks within the primary motor cortex (M1. These mechanisms are identified for limb muscles but it is unclear whether they share properties with trunk muscles. The aim was to determine whether it was possible to test the intracortical inhibition and facilitation of the deep multifidus muscle fascicles (DM and at which inter-stimulus intervals (ISI.In ten pain-free individuals, TMS was applied over M1 and motor evoked potentials (MEP were recorded using fine-wire electrodes in DM. MEPs were conditioned with subthreshold stimuli at ISIs of 1 to 12 ms to test short-interval intracortical inhibition (SICI and at 15 ms for long-interval intracortical facilitation. Short-interval facilitation (SICF was tested using 1-ms ISI.SICI of DM was consistently obtained with ISI of 1-, 3-, 4- and 12-ms. Facilitation of DM MEP was only identified using SICF paradigm.A similar pattern of MEP modulation with ISI changes for deep trunk and limb muscles implies that M1 networks share some functional properties.The ppTMS paradigm presents a potential to determine how M1 inhibitory and excitatory mechanisms participate in brain re-organization in back pain that affects control of trunk muscles.

  4. Depressed intracortical inhibition after long trains of subthreshold repetitive magnetic stimuli at low frequency.

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    Modugno, Nicola; Currà, Antonio; Conte, Antonella; Inghilleri, Maurizio; Fofi, Luisa; Agostino, Rocco; Manfredi, Mario; Berardelli, Alfredo

    2003-12-01

    Repetitive transcranial magnetic stimulation (rTMS) modulates cortical excitability. These effects outlast the rTMS train, and range from inhibition to facilitation according to the variables used for rTMS. Several studies have demonstrated short and long-term effects on motor evoked potential (MEP) size, whereas the effects on intracortical inhibition (ICI) and facilitation (ICF) are still unclear. We investigated short- (1-15 min), intermediate- (16-30 min), and long-term (6 h) effects on intracortical excitability. Fourteen healthy subjects were stimulated with rTMS trains of 900 pulses (1 Hz, 90% resting motor threshold (rMTh)), delivered over the primary motor cortex and the occipital area. MTh, MEP size, silent period, intracortical inhibition at short (ICI) and long inter-stimulus intervals, and ICF were tested before and after rTMS. ICI was reduced 16-30 min after 1 Hz rTMS trains over the primary motor area, whereas the other response variables remained unchanged. The ICI reduction at 16-30 min was reproducible on different days in the same subjects; it was absent at 6 h and after stimulation of the occipital area. Subthreshold 1 Hz rTMS decreases ICI by reducing the excitability of intracortical inhibitory interneurones or by altering the electrical properties of the facilitatory chain of neurons responsible for the I waves.

  5. Intracortical inhibition in the soleus muscle is reduced during the control of upright standing in both young and old adults

    NARCIS (Netherlands)

    Papegaaij, Selma; Baudry, Stéphane; Négyesi, János; Taube, Wolfgang; Hortobagyi, Tibor

    Purpose In a previous study, we reported that a short-interval intracortical inhibition (SICI) decreases in old but not in young adults when standing on foam vs. a rigid surface. Here, we examined if such an age by task difficulty interaction in motor cortical excitability also occurs in easier

  6. Association of intracortical inhibition with social cognition deficits in schizophrenia: Findings from a transcranial magnetic stimulation study.

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    Mehta, Urvakhsh Meherwan; Thirthalli, Jagadisha; Basavaraju, Rakshathi; Gangadhar, Bangalore N

    2014-09-01

    Abnormal cortical-inhibition has been hypothesized to underlie social-cognition deficits in schizophrenia. Studies using transcranial magnetic stimulation (TMS) as a neurophysiological probe have demonstrated cortical-inhibition deficits in this group. We compared TMS-measured short- and long-interval intracortical-inhibition (SICI & LICI) in antipsychotic-naïve (n=33) and medicated (n=21) schizophrenia patients and in healthy comparison subjects (n=45). We also studied the association between cortical-inhibition and social-cognition deficits in the patients. Antipsychotic-naïve patients had significant deficits in SICI (i.e., less inhibitory response). In this group, SICI had significant inverse correlations with emotion processing and a global social-cognition score. Impaired intracortical-inhibition may thus contribute to social-cognition deficits in schizophrenia. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Muscle Relaxation of the Foot Reduces Corticospinal Excitability of Hand Muscles and Enhances Intracortical Inhibition

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    Kato, Kouki; Muraoka, Tetsuro; Mizuguchi, Nobuaki; Nakagawa, Kento; Nakata, Hiroki; Kanosue, Kazuyuki

    2016-01-01

    The object of this study was to clarify the effects of foot muscle relaxation on activity in the primary motor cortex (M1) of the hand area. Subjects were asked to volitionally relax the right foot from sustained contraction of either the dorsiflexor (tibialis anterior; TA relaxation) or plantarflexor (soleus; SOL relaxation) in response to an auditory stimulus. Single- and paired-pulse transcranial magnetic stimulation (TMS) was delivered to the hand area of the left M1 at different time intervals before and after the onset of TA or SOL relaxation. Motor evoked potentials (MEPs) were recorded from the right extensor carpi radialis (ECR) and flexor carpi radialis (FCR). MEP amplitudes of ECR and FCR caused by single-pulse TMS temporarily decreased after TA and SOL relaxation onset, respectively, as compared with those of the resting control. Furthermore, short-interval intracortical inhibition (SICI) of ECR evaluated with paired-pulse TMS temporarily increased after TA relaxation onset. Our findings indicate that muscle relaxation of the dorsiflexor reduced corticospinal excitability of the ipsilateral hand muscles. This is most likely caused by an increase in intracortical inhibition. PMID:27242482

  8. Muscle relaxation of the foot reduces corticospinal excitability of hand muscles and enhances intracortical inhibition

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    Kouki eKato

    2016-05-01

    Full Text Available The object of this study was to clarify the effects of foot muscle relaxation on activity in the primary motor cortex of the hand area. Subjects were asked to volitionally relax the right foot from sustained contraction of either the dorsiflexor (tibialis anterior; TA relaxation or plantarflexor (soleus; SOL relaxation in response to an auditory stimulus. Single- and paired-pulse transcranial magnetic stimulation (TMS was delivered to the hand area of the left primary motor cortex at different time intervals before and after the onset of TA or SOL relaxation. Motor evoked potentials (MEPs were recorded from the right extensor carpi radialis (ECR and flexor carpi radialis (FCR. MEP amplitudes of ECR and FCR caused by single-pulse TMS temporarily decreased after TA and SOL relaxation onset, respectively, as compared with those of the resting control. Furthermore, short-interval intracortical inhibition (SICI of ECR evaluated with paired-pulse TMS temporarily increased after TA relaxation onset. Our findings indicate that muscle relaxation of the dorsiflexor reduced corticospinal excitability of the ipsilateral hand muscles. This is most likely caused by an increase in intracortical inhibition.

  9. Intracortical inhibition is modulated by phase of prosthetic rehabilitation in transtibial amputees

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    Brenton eHordacre

    2015-05-01

    Full Text Available Reorganisation of primary motor cortex (M1 is well described in long-term lower limb amputees. In contrast cortical reorganisation during the rehabilitation period after amputation is poorly understood. Thirteen transtibial amputees and thirteen gender matched control participants of similar age were recruited. Transcranial magnetic stimulation was used to assess corticomotor and intracortical excitability of M1 bilaterally. Neurophysiological assessments were conducted at admission, prosthetic casting, first walk and discharge. Gait variability at discharge was assessed as a functional measure. Compared to controls, amputees had reduced short-latency intracortical inhibition for the ipsilateral M1 at admission (p=0.01. Analysis across rehabilitation revealed short-latency intracortical inhibition was reduced for the contralateral M1 at first walk compared to discharge (p=0.003. For the ipsilateral M1 both short and long-latency intracortical inhibition were reduced at admission (p<0.05 and prosthetic casting (p<0.02. Analysis of the neurophysiology and gait function revealed several interesting relationships. For the contralateral M1, reduced inhibition at admission (p=0.04 and first walk (p=0.05 was associated with better gait function. For the ipsilateral M1, reduced inhibition at discharge (p=0.05 was associated with poor gait function. This study characterised intracortical excitability in rehabilitating amputees. A dichotomous relationship between reduced intracortical inhibition for each M1 and gait function was observed at different times. Intracortical inhibition may be an appropriate cortical biomarker of gait function in lower limb amputees during rehabilitation, but requires further investigation. Understanding M1 intracortical excitability of amputees undertaking prosthetic rehabilitation provides insight into brain reorganisation in the sub-acute post amputation period and may guide future studies seeking to improve rehabilitation

  10. Intracortical inhibition is modulated by phase of prosthetic rehabilitation in transtibial amputees

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    Hordacre, Brenton; Bradnam, Lynley V.; Barr, Christopher; Patritti, Benjamin L.; Crotty, Maria

    2015-01-01

    Reorganization of primary motor cortex (M1) is well-described in long-term lower limb amputees. In contrast cortical reorganization during the rehabilitation period after amputation is poorly understood. Thirteen transtibial amputees and 13 gender matched control participants of similar age were recruited. Transcranial magnetic stimulation was used to assess corticomotor and intracortical excitability of M1 bilaterally. Neurophysiological assessments were conducted at admission, prosthetic casting, first walk and discharge. Gait variability at discharge was assessed as a functional measure. Compared to controls, amputees had reduced short-latency intracortical inhibition (SICI) for the ipsilateral M1 at admission (p = 0.01). Analysis across rehabilitation revealed SICI was reduced for the contralateral M1 at first walk compared to discharge (p = 0.003). For the ipsilateral M1 both short and long-latency intracortical inhibition were reduced at admission (p rehabilitating amputees. A dichotomous relationship between reduced intracortical inhibition for each M1 and gait function was observed at different times. Intracortical inhibition may be an appropriate cortical biomarker of gait function in lower limb amputees during rehabilitation, but requires further investigation. Understanding M1 intracortical excitability of amputees undertaking prosthetic rehabilitation provides insight into brain reorganization in the sub-acute post-amputation period and may guide future studies seeking to improve rehabilitation outcomes. PMID:26042015

  11. Time course of corticospinal excitability and intracortical inhibition just before muscle relaxation

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    Tomotaka eSuzuki

    2016-01-01

    Full Text Available Using transcranial magnetic stimulation (TMS, we investigated how short-interval intracortical inhibition (SICI was involved with transient motor cortex excitability changes observed just before the transition from muscle contraction to muscle relaxation. Ten healthy participants performed a simultaneous relaxation task of the ipsilateral finger and foot, relaxing from 10% of their maximal voluntary contraction force after the go signal. In the simple reaction time paradigm, single or paired TMS pulses were randomly delivered after the go signal, and motor evoked potentials were recorded from the right first dorsal interosseous muscle. We analyzed the time course prior to the estimated relaxation reaction time, defined here as the onset of voluntary relaxation. SICI decreased in the 80–100 ms before relaxation reaction time, and motor evoked potentials were significantly greater in amplitude in the 60–80 ms period before relaxation reaction time than in the other intervals in single-pulse trials. TMS pulses did not effectively increase relaxation reaction time. These results show that cortical excitability in the early stage, before muscle relaxation, plays an important role in muscle relaxation control. SICI circuits may vary between decreased and increased activation to continuously maintain muscle relaxation during or after a relaxation response. With regard to motor cortex excitability dynamics, we suggest that SICI also dynamically changes throughout the muscle relaxation process.

  12. Delayed grip relaxation and altered modulation of intracortical inhibition with aging

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    Motawar, Binal; Stinear, James W.; Lauer, Abigail W.; Ramakrishnan, V. Viswanathan; Seo, Na Jin

    2015-01-01

    Grip relaxation is a voluntary action that requires an increase in short-interval intracortical inhibition (SICI) in healthy young adults, rather than a simple termination of excitatory drive. The way aging affects this voluntary inhibitory action and timing of grip relaxation is currently unknown. The objective of this study was to examine aging-related delays in grip relaxation and SICI modulation for the flexor digitorum superficialis (FDS) muscle during grip relaxation. The main finding was that young adults increased SICI to relax their grips, whereas older adults did not increase SICI with a prolonged grip relaxation time (prelaxation time). A secondary experiment showed that both young and older adults did not change H reflex excitability during grip relaxation. Our data suggest that grip relaxation is mediated by increased cortical inhibitory output in young adults, and aging-related impairment in increasing cortical inhibitory output may hamper timely cessation of muscle activity. Our data also suggest a lesser role of the spinal circuits in grip muscle relaxation. This knowledge may contribute to understanding of aging-related movement deterioration and development of interventions for improving modulation of SICI to improve muscle relaxation and movement coordination. PMID:26686531

  13. Influence of position and stimulation parameters on intracortical inhibition and facilitation in human tongue motor cortex

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    Kothari, Mohit; Svensson, Peter; Nielsen, Jørgen Feldbæk

    Paired-pulse transcranial magnetic stimulation (ppTMS) can be used to assess short-interval intracortical inhibitory (SICI) and facilitatory (ICF) networks. The aim of the study was to examine the influence of body positions (recline and supine), inter-stimulus intervals (ISI) between the test...... stimulus (TS) and conditioning stimulus (CS) and intensities of the TS and CS on the degree of SICI and ICF. In study 1 and 2, fourteen and seventeen healthy volunteers participated respectively. ppTMS was applied over the “hot-spot” of the tongue motor cortex and motor evoked potentials (MEPs) were.......042) in study 1. In study 2, there was a significant effect of ISI (PICF in the tongue motor cortex....

  14. Changes in corticomotor excitability and intracortical inhibition of the primary motor cortex forearm area induced by anodal tDCS.

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    Xue Zhang

    Full Text Available OBJECTIVE: Previous studies have investigated how tDCS over the primary motor cortex modulates excitability in the intrinsic hand muscles. Here, we tested if tDCS changes corticomotor excitability and/or cortical inhibition when measured in the extensor carpi radialis (ECR and if these aftereffects can be successfully assessed during controlled muscle contraction. METHODS: We implemented a double blind cross-over design in which participants (n = 16 completed two sessions where the aftereffects of 20 min of 1 mA (0.04 mA/cm2 anodal vs sham tDCS were tested in a resting muscle, and two more sessions where the aftereffects of anodal vs sham tDCS were tested in an active muscle. RESULTS: Anodal tDCS increased corticomotor excitability in ECR when aftereffects were measured with a low-level controlled muscle contraction. Furthermore, anodal tDCS decreased short interval intracortical inhibition but only when measured at rest and after non-responders (n = 2 were removed. We found no changes in the cortical silent period. CONCLUSION: These findings suggest that targeting more proximal muscles in the upper limb with anodal tDCS is achievable and corticomotor excitability can be assessed in the presence of a low-level controlled contraction of the target muscle.

  15. Influence of position and stimulation parameters on intracortical inhibition and facilitation in human tongue motor cortex

    DEFF Research Database (Denmark)

    Kothari, Mohit; Svensson, Peter; Nielsen, Jørgen Feldbæk

    2014-01-01

    and supine), inter-stimulus intervals (ISI) between the test stimulus (TS) and conditioning stimulus (CS) and intensities of the TS and CS on the degree of SICI and ICF. In study 1 and 2, fourteen and seventeen healthy volunteers participated respectively. ppTMS was applied over the "hot-spot" of the tongue...... motor cortex and motor evoked potentials (MEPs) were recorded from contralateral tongue muscles. In study 1, single pulse and three ppTMS ISIs: 2, 10, 15 ms were applied 8 times each in three blocks (TS: 120%, 140% and 160% of resting motor threshold (rMT); CS: 80% of rMT) in two different body.......001) and interaction between intensity and ISIs (P=0.042) in study 1. In study 2, there was a significant effect of ISI (Ptongue motor pathways using ppTMS and SICI...

  16. Short-interval intracortical inhibition and facilitation targeting the tibialis anterior muscle

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    Davodian, Danny; Stevenson, Andrew James Thomas; Ziemann, Ulf

    2017-01-01

    muscles, TMS activation of lower limbs tend to predominantly activate I1 waves given the histological differences (Terao et al., Brain Research, 2000). In the present study, we investigated the effects of stimulation intensities of S1 and S2 on motor cortex (M1) excitability targeting the tibialis...... (SICF) is thoroughly examined (Ilić et al., JPhysiol., 2002), while relatively little is known for lower limb muscles. SICI and SICF are thought to be caused by interaction of I3 waves (Hanajima et al., JPhysiol., 1998; Hanajima et al., JPhysiol., 2002) and while these can be elicited in upper limb...

  17. Intracortical inhibitory and excitatory circuits in subjects with minimal hepatic encephalopathy: a TMS study.

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    Nardone, Raffaele; De Blasi, Pierpaolo; Höller, Yvonne; Brigo, Francesco; Golaszewski, Stefan; Frey, Vanessa N; Orioli, Andrea; Trinka, Eugen

    2016-10-01

    Minimal hepatic encephalopathy (MHE) is the earliest form of hepatic encephalopathy (HE) and affects up to 80 % of patients with liver cirrhosis. By definition, MHE is characterized by psychomotor slowing and subtle cognitive deficits,  but obvious clinical manifestations are lacking. Given its covert nature, MHE is often underdiagnosed. This study was aimed at detecting neurophysiological changes, as assessed by means of transcranial magnetic stimulation (TMS), involved in the early pathogenesis of the HE. We investigated motor cortex excitability in 15 patients with MHE and in 15 age-matched age-matched cirrhotic patients without MHE; the resting motor threshold, the short-interval intracortical inhibition (SICI) and the intracortical facilitation (ICF) were examined. Paired-pulse TMS revealed significant increased SICI and reduced ICF in the patients with MHE. These findings may reflect abnormalities in intrinsic brain activity and altered organization of functional connectivity networks. In particular, the results suggest a shift in the balance between intracortical inhibitory and excitatory mechanisms towards a net increase of inhibitory neurotransmission. Together with other neurophysiological (in particular EEG) and neuroimaging techniques, TMS may thus provide early markers of cerebral dysfunction in cirrhotic patients with MHE.

  18. Patients in a vegetative state following traumatic brain injury display a reduced intracortical modulation.

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    Bagnato, Sergio; Boccagni, Cristina; Sant'Angelo, Antonino; Prestandrea, Caterina; Rizzo, Silvia; Galardi, Giuseppe

    2012-10-01

    Patients in coma who fail to wake develop a condition known as a vegetative state (VS). While we know that some cortical activities exist in patients in VS, it remains unclear whether interneuronal modulation can be abnormal in the cerebral cortex of these patients. The aim of the study was to evaluate the inhibitory and excitatory interneuronal circuits in patients in VS following a traumatic brain injury. Cortical excitability was studied in 5 VS patients and in 10 healthy subjects using paired pulses transcranial magnetic stimulation (TMS). Resting motor threshold and intracortical inhibition and facilitation at short intervals (2 and 10 ms, respectively) were evaluated. Two patients were studied again after their level of consciousness transitioned into a minimally conscious state (MCS). Both intracortical inhibition and facilitation were significantly reduced in patients compared to healthy subjects (p<0.05). In addition, these results did not significantly change in the 2 patients who evolved into a MCS. This is the first report showing an abnormal cortical excitability in patients in VS. Our findings suggest a pathophysiological base for future work aiming to restore the lack of interneuronal transmission in patients in VS. Copyright © 2012 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  19. Intracortical neural interface for prosthetic applications.

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    Ortmann, Valerij; Baziyan, Boris Kh

    2007-01-01

    New design of intracortical penetrating electrodes with integrated electronic front end is presented. The main advantage of the presented manufacturing technology is a simple customization of the electrode lengths and arrangement, according to the brain geometry of the specific patient. The neural interface may be used for the stimulation of the inner cortical layers and for recording of evoked potentials. Experimental investigations on several cats have shown the higher effectiveness of the intracortical stimulation of the primary visual cortex in comparison to surface electrodes.

  20. Intracortical osteoblastic osteosarcoma with oncogenic rickets

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    Hasegawa, T.; Hirohashi, Setsuo; Shimoda, Tadakazu; Yokoyama, Ryohei; Beppu, Yasuo; Maeda, Shotaro

    1999-01-01

    Intracortical osteosarcoma is the rarest variant of osteosarcoma, occurring within, and usually confined to, the cortical bone. Oncogenic osteomalacia, or rickets, is an unusual clinicopathologic entity in which vitamin D-resistant osteomalacia, or rickets, occurs in association with some tumors of soft tissue or bone. We present a case of oncogenic rickets associated with intracortical osteosarcoma of the tibia in a 9-year-old boy, whose roentgenographic abnormalities of rickets disappeared and pertinent laboratory data except for serum alkaline phosphatase became normal after surgical resection of the tumor. Histologically, the tumor was an osteosarcoma with a prominent osteoblastic pattern. An unusual microscopic feature was the presence of matrix mineralization showing rounded calcified structures (calcified spherules). Benign osteoblastic tumors, such as osteoid osteoma and osteoblastoma, must be considered in the differential diagnosis because of the relatively low cellular atypia and mitotic activity of this tumor. The infiltrating pattern with destruction or engulfment of normal bone is a major clue to the correct diagnosis of intracortical osteosarcoma. The co-existing radiographic changes of rickets were due to the intracortical osteosarcoma. (orig.)

  1. Intracortical osteoblastic osteosarcoma with oncogenic rickets

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, T.; Hirohashi, Setsuo [Pathology Division, National Cancer Center Research Institute, Tokyo (Japan); Shimoda, Tadakazu [Clinical Laboratory Division, National Cancer Center Hospital, Tokyo (Japan); Yokoyama, Ryohei; Beppu, Yasuo [Orthopedic Division, National Cancer Center Hospital, Tokyo (Japan); Maeda, Shotaro [Department of Pathology, Nippon Medical School Hospital, Tokyo (Japan)

    1999-01-01

    Intracortical osteosarcoma is the rarest variant of osteosarcoma, occurring within, and usually confined to, the cortical bone. Oncogenic osteomalacia, or rickets, is an unusual clinicopathologic entity in which vitamin D-resistant osteomalacia, or rickets, occurs in association with some tumors of soft tissue or bone. We present a case of oncogenic rickets associated with intracortical osteosarcoma of the tibia in a 9-year-old boy, whose roentgenographic abnormalities of rickets disappeared and pertinent laboratory data except for serum alkaline phosphatase became normal after surgical resection of the tumor. Histologically, the tumor was an osteosarcoma with a prominent osteoblastic pattern. An unusual microscopic feature was the presence of matrix mineralization showing rounded calcified structures (calcified spherules). Benign osteoblastic tumors, such as osteoid osteoma and osteoblastoma, must be considered in the differential diagnosis because of the relatively low cellular atypia and mitotic activity of this tumor. The infiltrating pattern with destruction or engulfment of normal bone is a major clue to the correct diagnosis of intracortical osteosarcoma. The co-existing radiographic changes of rickets were due to the intracortical osteosarcoma. (orig.) With 8 figs., 25 refs.

  2. Impaired intracortical transmission in G2019S leucine rich-repeat kinase Parkinson patients.

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    Ponzo, Viviana; Di Lorenzo, Francesco; Brusa, Livia; Schirinzi, Tommaso; Battistini, Stefania; Ricci, Claudia; Sambucci, Manolo; Caltagirone, Carlo; Koch, Giacomo

    2017-05-01

    A mutation in leucine-rich repeat kinase 2 is the most common cause of hereditary Parkinson's disease (PD), yet the neural mechanisms and the circuitry potentially involved are poorly understood. We used different transcranial magnetic stimulation protocols to explore in the primary motor cortex the activity of intracortical circuits and cortical plasticity (long-term potentiation) in patients with the G2019S leucine-rich repeat kinase 2 gene mutation when compared with idiopathic PD patients and age-matched healthy subjects. Paired pulse transcranial magnetic stimulation was used to investigate short intracortical inhibition and facilitation and short afferent inhibition. Intermittent theta burst stimulation, a form of repetitive transcranial magnetic stimulation, was used to test long-term potentiation-like cortical plasticity. Leucine-rich repeat kinase 2 and idiopathic PD were tested both in ON and in OFF l-dopa therapy. When compared with idiopathic PD and healthy subjects, leucine-rich repeat kinase 2 PD patients showed a remarkable reduction of short intracortical inhibition in both ON and in OFF l-dopa therapy. This reduction was paralleled by an increase of intracortical facilitation in OFF l-dopa therapy. Leucine-rich repeat kinase 2 PD showed abnormal long-term potentiation-like cortical plasticity in ON l-dopa therapy. The motor cortex in leucine-rich repeat kinase 2 mutated PD patients is strongly disinhibited and hyperexcitable. These abnormalities could be a result of an impairment of inhibitory (gamma-Aminobutyric acid) transmission eventually related to altered neurotransmitter release. © 2017 International Parkinson and Movement Disorder Society. © 2017 International Parkinson and Movement Disorder Society.

  3. Effect of Ovariectomy on Stimulating Intracortical Remodeling in Rats

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    Chun Lei Li

    2014-01-01

    Full Text Available Objective. Technically primates and dogs represent ideal models to investigate diseases characterized by abnormal intracortical remodeling. High expenses and ethical issues, however, restrict the use of those animals in research. Rodent models have been used as alternatives instead, but their value is limited, if none, because these animals lack intracortical bone remodeling. This study aimed at investigating the effect of ovariectomy onto the stimulation of intracortical remodeling in rat mandibles. Materials and Methods. Sixteen 12-week-old Spraque-Dawly (SD female rats were randomly assigned into two groups, receiving either ovariectomy or sham operation. All the rats were sacrificed 18 weeks postoperatively. The entire mandibles were harvested for microcomputed tomography (micro-CT and histomorphometric assessments. Results. Micro-CT examination showed significantly decreased bone mineral density (0.95 ± 0.01 versus 1.01 ± 0.02 g/cm3, P<0.001 and bone volume (65.78 ± 5.45 versus 87.41 ± 4.12%, P<0.001 in ovariectomy group. Histomorphometric assessment detected a sixfold increased intracortical bone remodeling as well as an increased bone modeling in mandibles of ovariectomized rats. Conclusion. For the first time, to the authors’ knowledge, it was detected that ovariectomy stimulates intracortical remodeling in rat mandibles. This animal model might be of use to study various bone diseases associated with an abnormal intracortical remodeling process.

  4. Theoretical analysis of intracortical microelectrode recordings

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    Lempka, Scott F.; Johnson, Matthew D.; Moffitt, Michael A.; Otto, Kevin J.; Kipke, Daryl R.; McIntyre, Cameron C.

    2011-08-01

    Advanced fabrication techniques have now made it possible to produce microelectrode arrays for recording the electrical activity of a large number of neurons in the intact brain for both clinical and basic science applications. However, the long-term recording performance desired for these applications is hindered by a number of factors that lead to device failure or a poor signal-to-noise ratio (SNR). The goal of this study was to identify factors that can affect recording quality using theoretical analysis of intracortical microelectrode recordings of single-unit activity. Extracellular microelectrode recordings were simulated with a detailed multi-compartment cable model of a pyramidal neuron coupled to a finite-element volume conductor head model containing an implanted recording microelectrode. Recording noise sources were also incorporated into the overall modeling infrastructure. The analyses of this study would be very difficult to perform experimentally; however, our model-based approach enabled a systematic investigation of the effects of a large number of variables on recording quality. Our results demonstrate that recording amplitude and noise are relatively independent of microelectrode size, but instead are primarily affected by the selected recording bandwidth, impedance of the electrode-tissue interface and the density and firing rates of neurons surrounding the recording electrode. This study provides the theoretical groundwork that allows for the design of the microelectrode and recording electronics such that the SNR is maximized. Such advances could help enable the long-term functionality required for chronic neural recording applications.

  5. Reduced motor cortical inhibition in migraine: A blinded transcranial magnetic stimulation study.

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    Neverdahl, J P; Omland, P M; Uglem, M; Engstrøm, M; Sand, T

    2017-12-01

    To investigate motor cortical excitability, inhibition, and facilitation with navigated transcranial magnetic stimulation (TMS) in migraine in a blinded cross-sectional study. Resting motor threshold (RMT), cortical silent period (CSP), short-interval intracortical inhibition (SICI), and intracortical facilitation (ICF) were compared in 27 interictal migraineurs and 33 controls. 24 female interictal migraineurs and 27 female controls were compared in subgroup analyses. Seven preictal migraineurs were also compared to the interictal group in a hypothesis-generating analysis. Investigators were blinded for diagnosis during recording and analysis of data. SICI was decreased in interictal migraineurs when compared to healthy controls (p=0.013), CSP was shortened in female interictal migraineurs (p=0.041). ICF was decreased in preictal compared to interictal migraineurs (p=0.023). RMT and ICF were not different between interictal migraineurs and controls. Cortical inhibition was decreased in migraineurs between attacks, primarily in a female subgroup, indicating an importance of altered cortical inhibition in migraine. Previous studies on motor cortical excitability in migraineurs have yielded varying results. This relatively large and blinded study provides support for altered cortical inhibition in migraine. Measuring intracortical facilitation in the period preceding migraine attacks may be of interest for future studies. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

  6. A single bout of high-intensity interval training improves motor skill retention in individuals with stroke

    DEFF Research Database (Denmark)

    Nepveu, Jean-Francois; Thiel, Alexander; Tang, Ada

    2017-01-01

    BACKGROUND: One bout of high-intensity cardiovascular exercise performed immediately after practicing a motor skill promotes changes in the neuroplasticity of the motor cortex and facilitates motor learning in nondisabled individuals. OBJECTIVE: To determine if a bout of exercise performed at high...... a motor task, the exercise group performed 15 minutes of high-intensity interval training while the control group rested. Twenty-four hours after motor practice all participants completed a test of the motor task to assess skill retention. RESULTS: The graded exercise test reduced interhemispheric...... imbalances in GABAA-mediated short-interval intracortical inhibition but changes in other markers of excitability were not statistically significant. The group that performed high-intensity interval training showed a better retention of the motor skill. CONCLUSIONS: The performance of a maximal graded...

  7. The EEG microstate topography is predominantly determined by intracortical sources in the alpha band.

    Science.gov (United States)

    Milz, P; Pascual-Marqui, R D; Achermann, P; Kochi, K; Faber, P L

    2017-11-15

    microstate dynamics reflect a fundamental mechanism of the human brain that is altered in different mental states in health and disease. They are characterized by systematic transitions between four head-surface topographies, the EEG microstate classes. Our results show that intra-cortical alpha oscillations, which likely reflect decreased cortical excitability, primarily account for the emergence of these classes. We suggest that microstate class dynamics reflect transitions between four global attractor states that are characterized by selective inhibition of specific intra-cortical regions. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Acute aerobic exercise modulates primary motor cortex inhibition.

    Science.gov (United States)

    Mooney, Ronan A; Coxon, James P; Cirillo, John; Glenny, Helen; Gant, Nicholas; Byblow, Winston D

    2016-12-01

    Aerobic exercise can enhance neuroplasticity although presently the neural mechanisms underpinning these benefits remain unclear. One possible mechanism is through effects on primary motor cortex (M1) function via down-regulation of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). The aim of the present study was to examine how corticomotor excitability (CME) and M1 intracortical inhibition are modulated in response to a single bout of moderate intensity aerobic exercise. Ten healthy right-handed adults were participants. Single- and paired-pulse transcranial magnetic stimulation was applied over left M1 to obtain motor-evoked potentials in the right flexor pollicis brevis. We examined CME, cortical silent period (SP) duration, short- and long-interval intracortical inhibition (SICI, LICI), and late cortical disinhibition (LCD), before and after acute aerobic exercise (exercise session) or an equivalent duration without exercise (control session). Aerobic exercise was performed on a cycle ergometer for 30 min at a workload equivalent to 60 % of maximal cardiorespiratory fitness (VO 2 peak; heart rate reserve = 75 ± 3 %, perceived exertion = 13.5 ± 0.7). LICI was reduced at 10 (52 ± 17 %, P = 0.03) and 20 min (27 ± 8 %, P = 0.03) post-exercise compared to baseline (13 ± 4 %). No significant changes in CME, SP duration, SICI or LCD were observed. The present study shows that GABA B -mediated intracortical inhibition may be down-regulated after acute aerobic exercise. The potential effects this may have on M1 plasticity remain to be determined.

  9. Assessment of capacitor electrodes for intracortical neural stimulation.

    Science.gov (United States)

    Rose, T L; Kelliher, E M; Robblee, L S

    1985-01-01

    Capacitor electrodes offer the potential for the safest method of stimulation of neural tissue because they operate without any faradaic process occurring at the electrode-electrolyte interface. Their use eliminates problems associated with metal dissolution or water electrolysis which may occur with electrodes of noble metals. This paper reviews recent work aimed at increasing the charge storage density of capacitor electrodes to allow their application with the small areas of 10(-4) mm2 required for intracortical stimulation of single neurons. Increased charge storage with electrodes using anodic films such as TiO2 and Ta2O5 has been obtained by increasing the real surface area of microelectrodes. Experiments have also been done with BaTiO3 films which have a much higher dielectric constant than the anodic film dielectrics. State-of-the-art electrodes made with these materials, however, have a charge storage density which at best is comparable to that obtained with Pt and is considerably lower than electrochemically safe charge densities that have been reported for activated Ir. It is concluded that for very small intracortical electrodes, capacitor electrodes will not be competitive with electrodes which operate using surface localized faradaic reactions.

  10. PTH treatment activates intracortical bone remodeling in patients with hypoparathyroidism

    DEFF Research Database (Denmark)

    Sikjær, Tanja Tvistholm; Rejnmark, Lars; Thomsen, Jesper Skovhus

    2017-01-01

    Hypoparathyroidism (hypoPT) is characterized by a state of low bone turnover and high BMD. We have previously shown that hypoPT patients treated with PTH(1-84) for six months have highly increased bone turnover markers and a decrease in aBMD at the hip and spine(1). The present study aims...... to investigate the effect of PTH(1-84) on cortical bone and intracortical bone remodeling in hypoPT. The study was conducted on 20 transiliac bone biopsies from hypoPT patients after six months of treatment with either PTH(1-84) 100 µg s.c./day N=10 or placebo N=10. The groups were age- (±6 years) and gender......-matched. Age, duration of disease, and etiology of hypoPT did not differ between groups. A comprehensive analysis of the cortical bone was performed including estimates of cortical porosity, and pore density (# of pores/mm2). The remodeling stage of all intracortical pores was evaluated, and pore area...

  11. A brain-machine interface instructed by direct intracortical microstimulation

    Directory of Open Access Journals (Sweden)

    Joseph E O'Doherty

    2009-09-01

    Full Text Available Brain-machine interfaces (BMIs establish direct communications between the brain and artificial actuators. As such, they hold considerable promise for restoring mobility and communication in patients suffering from severe body paralysis. To achieve this end, future BMIs must also provide a means for delivering sensory signals from the actuators back to the brain. Prosthetic sensation is needed so that neuroprostheses can be better perceived and controlled. Here we show that a direct intracortical input can be added to a BMI to instruct rhesus monkeys in choosing the direction of reaching movements generated by the BMI. Somatosensory instructions were provided to two monkeys operating the BMI using either: (a vibrotactile stimulation of the monkey’s hands or (b multi-channel intracortical microstimulation (ICMS delivered to the primary somatosensory cortex (S1 in one monkey and posterior parietal cortex (PP in the other. Stimulus delivery was contingent on the position of the computer cursor: the monkey placed it in the center of the screen to receive machine-brain recursive input. After two weeks of training, the same level of proficiency in utilizing somatosensory information was achieved with ICMS of S1 as with the stimulus delivered to the hand skin. ICMS of PP was not effective. These results indicate that direct, bi-directional communication between the brain and neuroprosthetic devices can be achieved through the combination of chronic multi-electrode recording and microstimulation of S1. We propose that in the future, bidirectional BMIs incorporating ICMS may become an effective paradigm for sensorizing neuroprosthetic devices.

  12. Influence of Waveform and Current Direction on Short-Interval Intracortical Facilitation

    DEFF Research Database (Denmark)

    Delvendahl, Igor; Lindemann, Hannes; Jung, Nikolai H

    2014-01-01

    -posterior (AP) current direction (AP-AP or PA-PA), whereas current direction was reversed between first and second pulse for half-sine paired-pulse stimulation (PA-AP and AP-PA). RESULTS: Monophasic AP-AP stimulation resulted in stronger early SICF at 1.4 ms relative to late SICF at 2.8 and 4.4 ms, whereas...... monophasic PA-PA stimulation produced SICF of comparable size at all three peaks. With half-sine stimulation the third SICF peak was reduced for PA-AP current orientation compared with AP-PA. CONCLUSION: SICF elicited using monophasic as well as half-sine pulses is affected by current direction at clearly...

  13. Intracortical chondroblastoma mimicking intra-articular osteoid osteoma

    Energy Technology Data Exchange (ETDEWEB)

    Ishida, Tsuyoshi; Mukai, Kiyoshi [First Department of Pathology, Tokyo Medical University, Shinjuku 6-1-1, Shinjuku-ku, Tokyo 160-8402 (Japan); Goto, Takahiro [Department of Orthopaedic Surgery, Faculty of Medicine, The University of Tokyo, Tokyo (Japan); Motoi, Noriko [Department of Pathology, Toranomon Hospital, Tokyo (Japan)

    2002-10-01

    We report a case of intra-articular intracortical chondroblastoma of the femoral condyle which radiologically appeared to be osteoid osteoma. A 19-year-old woman presented with a 3-year history of gradually increasing pain in the right knee and had been on nonsteroidal anti-inflammatory drugs for pain relief. Laboratory data were within normal limits. Radiographs showed a well-demarcated lucent lesion in the medial condyle of the right femur. A nidus-like lesion with calcifications and a sclerotic rim located in the cortex was imaged by computed tomography scan. Magnetic resonance imaging revealed bone marrow edema and soft tissue swelling around the lesion, with low signal intensity of the nidus-like lesion on both T1- and T2-weighted images. The lesion was excised en bloc and the histological diagnosis of chondroblastoma was made. A mild inflammatory reaction was observed in the bone marrow and synovium around the tumor. The chondroblastoma cells were shown to express cyclooxygenase-2 with immunohistochemistry. (orig.)

  14. A computational model that predicts behavioral sensitivity to intracortical microstimulation

    Science.gov (United States)

    Kim, Sungshin; Callier, Thierri; Bensmaia, Sliman J.

    2017-02-01

    Objective. Intracortical microstimulation (ICMS) is a powerful tool to investigate the neural mechanisms of perception and can be used to restore sensation for patients who have lost it. While sensitivity to ICMS has previously been characterized, no systematic framework has been developed to summarize the detectability of individual ICMS pulse trains or the discriminability of pairs of pulse trains. Approach. We develop a simple simulation that describes the responses of a population of neurons to a train of electrical pulses delivered through a microelectrode. We then perform an ideal observer analysis on the simulated population responses to predict the behavioral performance of non-human primates in ICMS detection and discrimination tasks. Main results. Our computational model can predict behavioral performance across a wide range of stimulation conditions with high accuracy (R 2 = 0.97) and generalizes to novel ICMS pulse trains that were not used to fit its parameters. Furthermore, the model provides a theoretical basis for the finding that amplitude discrimination based on ICMS violates Weber’s law. Significance. The model can be used to characterize the sensitivity to ICMS across the range of perceptible and safe stimulation regimes. As such, it will be a useful tool for both neuroscience and neuroprosthetics.

  15. Discriminability of Single and Multichannel Intracortical Microstimulation within Somatosensory Cortex

    Directory of Open Access Journals (Sweden)

    Cynthia Kay Overstreet

    2016-12-01

    Full Text Available The addition of tactile and proprioceptive feedback to neuroprosthetic limbs is expected to significantly improve the control of these devices. Intracortical microstimulation (ICMS of somatosensory cortex is a promising method of delivering this sensory feedback. To date, the main focus of somatosensory ICMS studies has been to deliver discriminable signals, corresponding to varying intensity, to a single location in cortex. However, multiple independent and simultaneous streams of sensory information will need to be encoded by ICMS to provide functionally relevant feedback for a neuroprosthetic limb (e.g. encoding contact events and pressure on multiple digits.In this study, we evaluated the ability of an awake, behaving non-human primate (Macaca mulatta to discriminate ICMS stimuli delivered on multiple electrodes spaced within somatosensory cortex. We delivered serial stimulation on single electrodes to evaluate the discriminability of sensations corresponding to ICMS of distinct cortical locations. Additionally, we delivered trains of multichannel stimulation, derived from a tactile sensor, synchronously across multiple electrodes. Our results indicate that discrimination of multiple ICMS stimuli is a challenging task, but that discriminable sensory percepts can be elicited by both single and multichannel ICMS on electrodes spaced within somatosensory cortex.

  16. Black bears with longer disuse (hibernation) periods have lower femoral osteon population density and greater mineralization and intracortical porosity.

    Science.gov (United States)

    Wojda, Samantha J; Weyland, David R; Gray, Sarah K; McGee-Lawrence, Meghan E; Drummer, Thomas D; Donahue, Seth W

    2013-08-01

    Intracortical bone remodeling is persistent throughout life, leading to age related increases in osteon population density (OPD). Intracortical porosity also increases with age in many mammals including humans, contributing to bone fragility and fracture risk. Unbalanced bone resorption and formation during disuse (e.g., physical inactivity) also increases intracortical porosity. In contrast, hibernating bears are a naturally occurring model for the prevention of both age-related and disuse osteoporoses. Intracortical bone remodeling is decreased during hibernation, but resorption and formation remain balanced. Black bears spend 0.25-7 months in hibernation annually depending on climate and food availability. We found longer hibernating bears demonstrate lower OPD and higher cortical bone mineralization than bears with shorter hibernation durations, but we surprisingly found longer hibernating bears had higher intracortical porosity. However, bears from three different latitudes showed age-related decreases in intracortical porosity, indicating that regardless of hibernation duration, black bears do not show the disuse- or age-related increases in intracortical porosity which is typical of other animals. This ability to prevent increases in intracortical porosity likely contributes to their ability to maintain bone strength during prolonged periods of physical inactivity and throughout life. Improving our understanding of the unique bone metabolism in hibernating bears will potentially increase our ability to develop treatments for age- and disuse-related osteoporoses in humans. Copyright © 2013 Wiley Periodicals, Inc.

  17. Increased cross-education of muscle strength and reduced corticospinal inhibition following eccentric strength training.

    Science.gov (United States)

    Kidgell, D J; Frazer, A K; Daly, R M; Rantalainen, T; Ruotsalainen, I; Ahtiainen, J; Avela, J; Howatson, G

    2015-08-06

    Strength training of one limb results in a substantial increase in the strength of the untrained limb, however, it remains unknown what the corticospinal responses are following either eccentric or concentric strength training and how this relates to the cross-education of strength. The aim of this study was to determine if eccentric or concentric unilateral strength training differentially modulates corticospinal excitability, inhibition and the cross-transfer of strength. Changes in contralateral (left limb) concentric strength, eccentric strength, motor-evoked potentials, short-interval intracortical inhibition and silent period durations were analyzed in groups of young adults who exercised the right wrist flexors with either eccentric (N=9) or concentric (N=9) contractions for 12 sessions over 4weeks. Control subjects (N=9) did not train. Following training, both groups exhibited a significant strength gain in the trained limb (concentric group increased concentric strength by 64% and eccentric group increased eccentric strength by 62%) and the extent of the cross-transfer of strength was 28% and 47% for the concentric and eccentric group, respectively, which was different between groups (P=0.031). Transcranial magnetic stimulation revealed that eccentric training reduced intracortical inhibition (37%), silent period duration (15-27%) and increased corticospinal excitability (51%) compared to concentric training for the untrained limb (P=0.033). There was no change in the control group. The results show that eccentric training uniquely modulates corticospinal excitability and inhibition of the untrained limb to a greater extent than concentric training. These findings suggest that unilateral eccentric contractions provide a greater stimulus in cross-education paradigms and should be an integral part of the rehabilitative process following unilateral injury to maximize the response. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

  18. Interval Training

    Science.gov (United States)

    Healthy Lifestyle Fitness Interval training can help you get the most out of your workout. By Mayo Clinic Staff Are you ready to shake up ... more time at the gym? Consider aerobic interval training. Once the domain of elite athletes, interval training ...

  19. Intra-cortical excitability in healthy human subjects after tongue training

    DEFF Research Database (Denmark)

    Baad-Hansen, Lene; Blicher, Jakob; Lapitskaya, Natallia

    2009-01-01

    ) and intra-cortical facilitatory (ICF) networks. This study examined changes in SICI and ICF in tongue motor cortex after tongue training in 11 healthy volunteers using ppTMS. Paired pulse TMS was applied to the 'hot-spot' for the tongue motor cortex and motor-evoked potentials (MEPs) were recorded from...... tongue muscles. In tongue motor cortex, bilateral SICI (P 0.063). The success rate improved during training (P ... to changes in single MEP amplitude (P 0.113). This first study of SICI/ICF after tongue training showed no training-related changes in intra-cortical inhibitory or facilitatory networks. However, there was an association between task performance and changes in corticomotor...

  20. The Effect of the Elimination of Micromotion and Tissue Strain on Intracortical Device Performance

    Science.gov (United States)

    2017-10-01

    would exhibit an improved tissue response and enhanced device performance, there have been no definitive studies that definitively test this...hypothesis. We are developing intracortical probes using shape memory polymers (SMPs): materials which have the capacity to transition from stiff to soft upon...Does probe softening improve the surrounding tissue response and recording performance of the device? The short term impact will be on the scientific

  1. The Effect of the Elimination of Micromotion and Tissue Strain on Intracortical Device Performance

    Science.gov (United States)

    2016-10-01

    Loctite Hysol Medical grade device epoxy. Our first test devices were composed of SMP 7, the fully softening polymer . Close examination of our initial...studies that definitively test this hypothesis. We are developing intracortical probes using shape memory polymers (SMPs): materials which have the...capacity to transition from stiff to soft upon implantation. We will tune the degree of stiffness such that we can definitively address a fundamental

  2. Comparative pathogenesis of radium-induced intracortical bone lesions in humans and beagles

    International Nuclear Information System (INIS)

    Pool, R.R.; Morgan, J.P.; Parks, N.J.; Farnham, J.E.; Littman, M.S.

    1982-01-01

    An interlaboratory research team from our Laboratory and the Center for Human Radiobiology at Argonne National Laboratory has performed an initial comparison of intracortical lesions in the long bones of dog and man following chronic radium deposition in the skeleton. The sequential radiographic appearance and morphology of radiation osteodystrophy is discussed. The role of osteodystrohy in the evaluation of bone tumors in the dog is examined

  3. Augmenting intracortical brain-machine interface with neurally driven error detectors

    Science.gov (United States)

    Even-Chen, Nir; Stavisky, Sergey D.; Kao, Jonathan C.; Ryu, Stephen I.; Shenoy, Krishna V.

    2017-12-01

    Objective. Making mistakes is inevitable, but identifying them allows us to correct or adapt our behavior to improve future performance. Current brain-machine interfaces (BMIs) make errors that need to be explicitly corrected by the user, thereby consuming time and thus hindering performance. We hypothesized that neural correlates of the user perceiving the mistake could be used by the BMI to automatically correct errors. However, it was unknown whether intracortical outcome error signals were present in the premotor and primary motor cortices, brain regions successfully used for intracortical BMIs. Approach. We report here for the first time a putative outcome error signal in spiking activity within these cortices when rhesus macaques performed an intracortical BMI computer cursor task. Main results. We decoded BMI trial outcomes shortly after and even before a trial ended with 96% and 84% accuracy, respectively. This led us to develop and implement in real-time a first-of-its-kind intracortical BMI error ‘detect-and-act’ system that attempts to automatically ‘undo’ or ‘prevent’ mistakes. The detect-and-act system works independently and in parallel to a kinematic BMI decoder. In a challenging task that resulted in substantial errors, this approach improved the performance of a BMI employing two variants of the ubiquitous Kalman velocity filter, including a state-of-the-art decoder (ReFIT-KF). Significance. Detecting errors in real-time from the same brain regions that are commonly used to control BMIs should improve the clinical viability of BMIs aimed at restoring motor function to people with paralysis.

  4. Interval Training.

    Science.gov (United States)

    President's Council on Physical Fitness and Sports, Washington, DC.

    Regardless of the type of physical activity used, interval training is simply repeated periods of physical stress interspersed with recovery periods during which activity of a reduced intensity is performed. During the recovery periods, the individual usually keeps moving and does not completely recover before the next exercise interval (e.g.,…

  5. Decoder calibration with ultra small current sample set for intracortical brain-machine interface.

    Science.gov (United States)

    Zhang, Peng; Ma, Xuan; Chen, Luyao; Zhou, Jin; Wang, Changyong; Li, Wei; He, Jiping

    2018-04-01

    Intracortical brain-machine interfaces (iBMIs) aim to restore efficient communication and movement ability for paralyzed patients. However, frequent recalibration is required for consistency and reliability, and every recalibration will require relatively large most current sample set. The aim in this study is to develop an effective decoder calibration method that can achieve good performance while minimizing recalibration time. Two rhesus macaques implanted with intracortical microelectrode arrays were trained separately on movement and sensory paradigm. Neural signals were recorded to decode reaching positions or grasping postures. A novel principal component analysis-based domain adaptation (PDA) method was proposed to recalibrate the decoder with only ultra small current sample set by taking advantage of large historical data, and the decoding performance was compared with other three calibration methods for evaluation. The PDA method closed the gap between historical and current data effectively, and made it possible to take advantage of large historical data for decoder recalibration in current data decoding. Using only ultra small current sample set (five trials of each category), the decoder calibrated using the PDA method could achieve much better and more robust performance in all sessions than using other three calibration methods in both monkeys. (1) By this study, transfer learning theory was brought into iBMIs decoder calibration for the first time. (2) Different from most transfer learning studies, the target data in this study were ultra small sample set and were transferred to the source data. (3) By taking advantage of historical data, the PDA method was demonstrated to be effective in reducing recalibration time for both movement paradigm and sensory paradigm, indicating a viable generalization. By reducing the demand for large current training data, this new method may facilitate the application of intracortical brain-machine interfaces in

  6. Decoder calibration with ultra small current sample set for intracortical brain-machine interface

    Science.gov (United States)

    Zhang, Peng; Ma, Xuan; Chen, Luyao; Zhou, Jin; Wang, Changyong; Li, Wei; He, Jiping

    2018-04-01

    Objective. Intracortical brain-machine interfaces (iBMIs) aim to restore efficient communication and movement ability for paralyzed patients. However, frequent recalibration is required for consistency and reliability, and every recalibration will require relatively large most current sample set. The aim in this study is to develop an effective decoder calibration method that can achieve good performance while minimizing recalibration time. Approach. Two rhesus macaques implanted with intracortical microelectrode arrays were trained separately on movement and sensory paradigm. Neural signals were recorded to decode reaching positions or grasping postures. A novel principal component analysis-based domain adaptation (PDA) method was proposed to recalibrate the decoder with only ultra small current sample set by taking advantage of large historical data, and the decoding performance was compared with other three calibration methods for evaluation. Main results. The PDA method closed the gap between historical and current data effectively, and made it possible to take advantage of large historical data for decoder recalibration in current data decoding. Using only ultra small current sample set (five trials of each category), the decoder calibrated using the PDA method could achieve much better and more robust performance in all sessions than using other three calibration methods in both monkeys. Significance. (1) By this study, transfer learning theory was brought into iBMIs decoder calibration for the first time. (2) Different from most transfer learning studies, the target data in this study were ultra small sample set and were transferred to the source data. (3) By taking advantage of historical data, the PDA method was demonstrated to be effective in reducing recalibration time for both movement paradigm and sensory paradigm, indicating a viable generalization. By reducing the demand for large current training data, this new method may facilitate the application

  7. The Duration of Motor Responses Evoked with Intracortical Microstimulation in Rats Is Primarily Modulated by Stimulus Amplitude and Train Duration.

    Directory of Open Access Journals (Sweden)

    Meghan Watson

    Full Text Available Microstimulation of brain tissue plays a key role in a variety of sensory prosthetics, clinical therapies and research applications, however the effects of stimulation parameters on the responses they evoke remain widely unknown. In particular, the effects of parameters when delivered in the form of a stimulus train as opposed to a single pulse are not well understood despite the prevalence of stimulus train use. We aimed to investigate the contribution of each parameter of a stimulus train to the duration of the motor responses they evoke in forelimb muscles. We used constant-current, biphasic, square wave pulse trains in acute terminal experiments under ketamine anaesthesia. Stimulation parameters were systematically tested in a pair-wise fashion in the caudal forelimb region of the motor cortex in 7 Sprague-Dawley rats while motor evoked potential (MEP recordings from the forelimb were used to quantify the influence of each parameter in the train. Stimulus amplitude and train duration were shown to be the dominant parameters responsible for increasing the total duration of the MEP, while interphase interval had no effect. Increasing stimulus frequency from 100-200 Hz or pulse duration from 0.18-0.34 ms were also effective methods of extending response durations. Response duration was strongly correlated with peak time and amplitude. Our findings suggest that motor cortex intracortical microstimulations are often conducted at a higher frequency rate and longer train duration than necessary to evoke maximal response duration. We demonstrated that the temporal properties of the evoked response can be both predicted by certain response metrics and modulated via alterations to the stimulation signal parameters.

  8. The Duration of Motor Responses Evoked with Intracortical Microstimulation in Rats Is Primarily Modulated by Stimulus Amplitude and Train Duration.

    Science.gov (United States)

    Watson, Meghan; Sawan, Mohamad; Dancause, Numa

    2016-01-01

    Microstimulation of brain tissue plays a key role in a variety of sensory prosthetics, clinical therapies and research applications, however the effects of stimulation parameters on the responses they evoke remain widely unknown. In particular, the effects of parameters when delivered in the form of a stimulus train as opposed to a single pulse are not well understood despite the prevalence of stimulus train use. We aimed to investigate the contribution of each parameter of a stimulus train to the duration of the motor responses they evoke in forelimb muscles. We used constant-current, biphasic, square wave pulse trains in acute terminal experiments under ketamine anaesthesia. Stimulation parameters were systematically tested in a pair-wise fashion in the caudal forelimb region of the motor cortex in 7 Sprague-Dawley rats while motor evoked potential (MEP) recordings from the forelimb were used to quantify the influence of each parameter in the train. Stimulus amplitude and train duration were shown to be the dominant parameters responsible for increasing the total duration of the MEP, while interphase interval had no effect. Increasing stimulus frequency from 100-200 Hz or pulse duration from 0.18-0.34 ms were also effective methods of extending response durations. Response duration was strongly correlated with peak time and amplitude. Our findings suggest that motor cortex intracortical microstimulations are often conducted at a higher frequency rate and longer train duration than necessary to evoke maximal response duration. We demonstrated that the temporal properties of the evoked response can be both predicted by certain response metrics and modulated via alterations to the stimulation signal parameters.

  9. Virtual typing by people with tetraplegia using a self-calibrating intracortical brain-computer interface.

    Science.gov (United States)

    Jarosiewicz, Beata; Sarma, Anish A; Bacher, Daniel; Masse, Nicolas Y; Simeral, John D; Sorice, Brittany; Oakley, Erin M; Blabe, Christine; Pandarinath, Chethan; Gilja, Vikash; Cash, Sydney S; Eskandar, Emad N; Friehs, Gerhard; Henderson, Jaimie M; Shenoy, Krishna V; Donoghue, John P; Hochberg, Leigh R

    2015-11-11

    Brain-computer interfaces (BCIs) promise to restore independence for people with severe motor disabilities by translating decoded neural activity directly into the control of a computer. However, recorded neural signals are not stationary (that is, can change over time), degrading the quality of decoding. Requiring users to pause what they are doing whenever signals change to perform decoder recalibration routines is time-consuming and impractical for everyday use of BCIs. We demonstrate that signal nonstationarity in an intracortical BCI can be mitigated automatically in software, enabling long periods (hours to days) of self-paced point-and-click typing by people with tetraplegia, without degradation in neural control. Three key innovations were included in our approach: tracking the statistics of the neural activity during self-timed pauses in neural control, velocity bias correction during neural control, and periodically recalibrating the decoder using data acquired during typing by mapping neural activity to movement intentions that are inferred retrospectively based on the user's self-selected targets. These methods, which can be extended to a variety of neurally controlled applications, advance the potential for intracortical BCIs to help restore independent communication and assistive device control for people with paralysis. Copyright © 2015, American Association for the Advancement of Science.

  10. Generation of Stimulus Triggering from Intracortical Spike Activity for Brain-Machine-Body Interfaces (BMBIs).

    Science.gov (United States)

    Shahdoost, Shahab; Nudo, Randolph; Mohseni, Pedram

    2016-10-05

    Brain-machine-body interfaces (BMBIs) aim to create an artificial connection in the nervous system by converting neural activity recorded from one cortical region to electrical stimuli delivered to another cortical region, spinal cord, or muscles in real-time. In particular, conditioning-mode BMBIs utilize such activity-dependent stimulation strategies to induce functional re-organization in the nervous system and promote functional recovery after injury by exploiting mechanisms underlying neuroplasticity. This paper reports on reconfigurable, field-programmable gate array (FPGA)-based implementation of a translation algorithm to extract multichannel stimulus trigger signals from intracortical neural spike activity. The approach features digital spike discrimination based on user-set thresholding and time-amplitude windowing, decision making to support different triggering patterns for various stimulation scenarios, as well as trigger-pattern-dependent blanking schemes for robust operation in the presence of stimulus artifacts. Readily lending itself to low-power, low-area implementation for future integration, the algorithm has been synthesized on a Cyclone II FPGA using Altera's Quartus II design software and validated experimentally with prerecorded intracortical neural spike activity from an anesthetized laboratory rat.

  11. Thalamocortical Connections Drive Intracortical Activation of Functional Columns in the Mislaminated Reeler Somatosensory Cortex.

    Science.gov (United States)

    Wagener, Robin J; Witte, Mirko; Guy, Julien; Mingo-Moreno, Nieves; Kügler, Sebastian; Staiger, Jochen F

    2016-02-01

    Neuronal wiring is key to proper neural information processing. Tactile information from the rodent's whiskers reaches the cortex via distinct anatomical pathways. The lemniscal pathway relays whisking and touch information from the ventral posteromedial thalamic nucleus to layer IV of the primary somatosensory "barrel" cortex. The disorganized neocortex of the reeler mouse is a model system that should severely compromise the ingrowth of thalamocortical axons (TCAs) into the cortex. Moreover, it could disrupt intracortical wiring. We found that neuronal intermingling within the reeler barrel cortex substantially exceeded previous descriptions, leading to the loss of layers. However, viral tracing revealed that TCAs still specifically targeted transgenically labeled spiny layer IV neurons. Slice electrophysiology and optogenetics proved that these connections represent functional synapses. In addition, we assessed intracortical activation via immediate-early-gene expression resulting from a behavioral exploration task. The cellular composition of activated neuronal ensembles suggests extensive similarities in intracolumnar information processing in the wild-type and reeler brains. We conclude that extensive ectopic positioning of neuronal partners can be compensated for by cell-autonomous mechanisms that allow for the establishment of proper connectivity. Thus, genetic neuronal fate seems to be of greater importance for correct cortical wiring than radial neuronal position. © The Author 2015. Published by Oxford University Press.

  12. Intracortical myelination in musicians with absolute pitch: Quantitative morphometry using 7‐T MRI

    Science.gov (United States)

    Knösche, Thomas R.

    2016-01-01

    Abstract Absolute pitch (AP) is known as the ability to recognize and label the pitch chroma of a given tone without external reference. Known brain structures and functions related to AP are mainly of macroscopic aspects. To shed light on the underlying neural mechanism of AP, we investigated the intracortical myeloarchitecture in musicians with and without AP using the quantitative mapping of the longitudinal relaxation rates with ultra‐high‐field magnetic resonance imaging at 7 T. We found greater intracortical myelination for AP musicians in the anterior region of the supratemporal plane, particularly the medial region of the right planum polare (PP). In the same region of the right PP, we also found a positive correlation with a behavioral index of AP performance. In addition, we found a positive correlation with a frequency discrimination threshold in the anterolateral Heschl's gyrus in the right hemisphere, demonstrating distinctive neural processes of absolute recognition and relative discrimination of pitch. Regarding possible effects of local myelination in the cortex and the known importance of the anterior superior temporal gyrus/sulcus for the identification of auditory objects, we argue that pitch chroma may be processed as an identifiable object property in AP musicians. Hum Brain Mapp 37:3486–3501, 2016. © 2016 Wiley Periodicals, Inc. PMID:27160707

  13. Intracortical myelination in musicians with absolute pitch: Quantitative morphometry using 7-T MRI.

    Science.gov (United States)

    Kim, Seung-Goo; Knösche, Thomas R

    2016-10-01

    Absolute pitch (AP) is known as the ability to recognize and label the pitch chroma of a given tone without external reference. Known brain structures and functions related to AP are mainly of macroscopic aspects. To shed light on the underlying neural mechanism of AP, we investigated the intracortical myeloarchitecture in musicians with and without AP using the quantitative mapping of the longitudinal relaxation rates with ultra-high-field magnetic resonance imaging at 7 T. We found greater intracortical myelination for AP musicians in the anterior region of the supratemporal plane, particularly the medial region of the right planum polare (PP). In the same region of the right PP, we also found a positive correlation with a behavioral index of AP performance. In addition, we found a positive correlation with a frequency discrimination threshold in the anterolateral Heschl's gyrus in the right hemisphere, demonstrating distinctive neural processes of absolute recognition and relative discrimination of pitch. Regarding possible effects of local myelination in the cortex and the known importance of the anterior superior temporal gyrus/sulcus for the identification of auditory objects, we argue that pitch chroma may be processed as an identifiable object property in AP musicians. Hum Brain Mapp 37:3486-3501, 2016. © 2016 Wiley Periodicals, Inc. © 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

  14. Resistance exercise-induced S6K1 kinase activity is not inhibited in human skeletal muscle despite prior activation of AMPK by high-intensity interval cycling

    DEFF Research Database (Denmark)

    Apró, William; Moberg, Marcus; Hamilton, D. Lee

    2015-01-01

    was not observed following R exercise only. In conclusion, cycling-induced elevation in AMPK activity does not inhibit mTOR complex 1 signaling after subsequent resistance exercise but may instead interfere with the hypertrophic response by influencing key components in protein breakdown....

  15. Relative contributions of intracortical and thalamo-cortical processes in the generation of alpha rhythms, revealed by partial coherence analysis

    NARCIS (Netherlands)

    Lopes da Silva, F.H.; Vos, J.E.; Mooibroek, J.; Rotterdam, A. van

    1980-01-01

    The thalamo-cortical relationships of alpha rhythms have been analysed in dogs using partial coherence function analysis. The objective was to clarify how far the large intracortical coherence commonly recorded between different cortical sites could depend on a common thalamic site. It was found

  16. interval functions

    Directory of Open Access Journals (Sweden)

    J. A. Chatfield

    1978-01-01

    Full Text Available Suppose N is a Banach space of norm |•| and R is the set of real numbers. All integrals used are of the subdivision-refinement type. The main theorem [Theorem 3] gives a representation of TH where H is a function from R×R to N such that H(p+,p+, H(p,p+, H(p−,p−, and H(p−,p each exist for each p and T is a bounded linear operator on the space of all such functions H. In particular we show that TH=(I∫abfHdα+∑i=1∞[H(xi−1,xi−1+−H(xi−1+,xi−1+]β(xi−1+∑i=1∞[H(xi−,xi−H(xi−,xi−]Θ(xi−1,xiwhere each of α, β, and Θ depend only on T, α is of bounded variation, β and Θ are 0 except at a countable number of points, fH is a function from R to N depending on H and {xi}i=1∞ denotes the points P in [a,b]. for which [H(p,p+−H(p+,p+]≠0 or [H(p−,p−H(p−,p−]≠0. We also define an interior interval function integral and give a relationship between it and the standard interval function integral.

  17. Intracortical circuits amplify sound-evoked activity in primary auditory cortex following systemic injection of salicylate in the rat

    Science.gov (United States)

    Chrostowski, Michael; Salvi, Richard J.; Allman, Brian L.

    2012-01-01

    A high dose of sodium salicylate temporarily induces tinnitus, mild hearing loss, and possibly hyperacusis in humans and other animals. Salicylate has well-established effects on cochlear function, primarily resulting in the moderate reduction of auditory input to the brain. Despite decreased peripheral sensitivity and output, salicylate induces a paradoxical enhancement of the sound-evoked field potential at the level of the primary auditory cortex (A1). Previous electrophysiologic studies have begun to characterize changes in thalamorecipient layers of A1; however, A1 is a complex neural circuit with recurrent intracortical connections. To describe the effects of acute systemic salicylate treatment on both thalamic and intracortical sound-driven activity across layers of A1, we applied current-source density (CSD) analysis to field potentials sampled across cortical layers in the anesthetized rat. CSD maps were normally characterized by a large, short-latency, monosynaptic, thalamically driven sink in granular layers followed by a lower amplitude, longer latency, polysynaptic, intracortically driven sink in supragranular layers. Following systemic administration of salicylate, there was a near doubling of both granular and supragranular sink amplitudes at higher sound levels. The supragranular sink amplitude input/output function changed from becoming asymptotic at approximately 50 dB to sharply nonasymptotic, often dominating the granular sink amplitude at higher sound levels. The supragranular sink also exhibited a significant decrease in peak latency, reflecting an acceleration of intracortical processing of the sound-evoked response. Additionally, multiunit (MU) activity was altered by salicylate; the normally onset/sustained MU response type was transformed into a primarily onset response type in granular and infragranular layers. The results from CSD analysis indicate that salicylate significantly enhances sound-driven response via intracortical circuits

  18. Visual Deprivation Causes Refinement of Intracortical Circuits in the Auditory Cortex

    Directory of Open Access Journals (Sweden)

    Xiangying Meng

    2015-08-01

    Full Text Available Loss of a sensory modality can lead to functional enhancement of the remaining senses. For example, short-term visual deprivations, or dark exposure (DE, can enhance neuronal responses in the auditory cortex to sounds. These enhancements encompass increased spiking rates and frequency selectivity as well as increased spiking reliability. Although we previously demonstrated enhanced thalamocortical transmission after DE, increased synaptic strength cannot account for increased frequency selectivity or reliability. We thus investigated whether other changes in the underlying circuitry contributed to improved neuronal responses. We show that DE can lead to refinement of intra- and inter-laminar connections in the mouse auditory cortex. Moreover, we use a computational model to show that the combination of increased transmission and circuit refinement can lead to increased firing reliability. Thus cross-modal influences can alter the spectral and temporal processing of sensory stimuli by refinement of thalamocortical and intracortical circuits.

  19. Advantages of closed-loop calibration in intracortical brain-computer interfaces for people with tetraplegia

    Science.gov (United States)

    Jarosiewicz, Beata; Masse, Nicolas Y.; Bacher, Daniel; Cash, Sydney S.; Eskandar, Emad; Friehs, Gerhard; Donoghue, John P.; Hochberg, Leigh R.

    2013-08-01

    Objective. Brain-computer interfaces (BCIs) aim to provide a means for people with severe motor disabilities to control their environment directly with neural activity. In intracortical BCIs for people with tetraplegia, the decoder that maps neural activity to desired movements has typically been calibrated using ‘open-loop’ (OL) imagination of control while a cursor automatically moves to targets on a computer screen. However, because neural activity can vary across contexts, a decoder calibrated using OL data may not be optimal for ‘closed-loop’ (CL) neural control. Here, we tested whether CL calibration creates a better decoder than OL calibration even when all other factors that might influence performance are held constant, including the amount of data used for calibration and the amount of elapsed time between calibration and testing. Approach. Two people with tetraplegia enrolled in the BrainGate2 pilot clinical trial performed a center-out-back task using an intracortical BCI, switching between decoders that had been calibrated on OL versus CL data. Main results. Even when all other variables were held constant, CL calibration improved neural control as well as the accuracy and strength of the tuning model. Updating the CL decoder using additional and more recent data resulted in further improvements. Significance. Differences in neural activity between OL and CL contexts contribute to the superiority of CL decoders, even prior to their additional ‘adaptive’ advantage. In the near future, CL decoder calibration may enable robust neural control without needing to pause ongoing, practical use of BCIs, an important step toward clinical utility.

  20. Neural control of finger movement via intracortical brain-machine interface.

    Science.gov (United States)

    Irwin, Z T; Schroeder, K E; Vu, P P; Bullard, A J; Tat, D M; Nu, C S; Vaskov, A; Nason, S R; Thompson, D E; Bentley, J N; Patil, P G; Chestek, C A

    2017-12-01

    Intracortical brain-machine interfaces (BMIs) are a promising source of prosthesis control signals for individuals with severe motor disabilities. Previous BMI studies have primarily focused on predicting and controlling whole-arm movements; precise control of hand kinematics, however, has not been fully demonstrated. Here, we investigate the continuous decoding of precise finger movements in rhesus macaques. In order to elicit precise and repeatable finger movements, we have developed a novel behavioral task paradigm which requires the subject to acquire virtual fingertip position targets. In the physical control condition, four rhesus macaques performed this task by moving all four fingers together in order to acquire a single target. This movement was equivalent to controlling the aperture of a power grasp. During this task performance, we recorded neural spikes from intracortical electrode arrays in primary motor cortex. Using a standard Kalman filter, we could reconstruct continuous finger movement offline with an average correlation of ρ  =  0.78 between actual and predicted position across four rhesus macaques. For two of the monkeys, this movement prediction was performed in real-time to enable direct brain control of the virtual hand. Compared to physical control, neural control performance was slightly degraded; however, the monkeys were still able to successfully perform the task with an average target acquisition rate of 83.1%. The monkeys' ability to arbitrarily specify fingertip position was also quantified using an information throughput metric. During brain control task performance, the monkeys achieved an average 1.01 bits s -1 throughput, similar to that achieved in previous studies which decoded upper-arm movements to control computer cursors using a standard Kalman filter. This is, to our knowledge, the first demonstration of brain control of finger-level fine motor skills. We believe that these results represent an important step

  1. Neural control of finger movement via intracortical brain-machine interface

    Science.gov (United States)

    Irwin, Z. T.; Schroeder, K. E.; Vu, P. P.; Bullard, A. J.; Tat, D. M.; Nu, C. S.; Vaskov, A.; Nason, S. R.; Thompson, D. E.; Bentley, J. N.; Patil, P. G.; Chestek, C. A.

    2017-12-01

    Objective. Intracortical brain-machine interfaces (BMIs) are a promising source of prosthesis control signals for individuals with severe motor disabilities. Previous BMI studies have primarily focused on predicting and controlling whole-arm movements; precise control of hand kinematics, however, has not been fully demonstrated. Here, we investigate the continuous decoding of precise finger movements in rhesus macaques. Approach. In order to elicit precise and repeatable finger movements, we have developed a novel behavioral task paradigm which requires the subject to acquire virtual fingertip position targets. In the physical control condition, four rhesus macaques performed this task by moving all four fingers together in order to acquire a single target. This movement was equivalent to controlling the aperture of a power grasp. During this task performance, we recorded neural spikes from intracortical electrode arrays in primary motor cortex. Main results. Using a standard Kalman filter, we could reconstruct continuous finger movement offline with an average correlation of ρ  =  0.78 between actual and predicted position across four rhesus macaques. For two of the monkeys, this movement prediction was performed in real-time to enable direct brain control of the virtual hand. Compared to physical control, neural control performance was slightly degraded; however, the monkeys were still able to successfully perform the task with an average target acquisition rate of 83.1%. The monkeys’ ability to arbitrarily specify fingertip position was also quantified using an information throughput metric. During brain control task performance, the monkeys achieved an average 1.01 bits s-1 throughput, similar to that achieved in previous studies which decoded upper-arm movements to control computer cursors using a standard Kalman filter. Significance. This is, to our knowledge, the first demonstration of brain control of finger-level fine motor skills. We believe

  2. Influence of inter-train interval on the plastic effects of rTMS.

    Science.gov (United States)

    Cash, Robin F H; Dar, Aisha; Hui, Jeanette; De Ruiter, Leo; Baarbé, Julianne; Fettes, Peter; Peters, Sarah; Fitzgerald, Paul B; Downar, Jonathan; Chen, Robert

    High frequency repetitive transcranial magnetic stimulation (rTMS) elicits plastic effects in excitatory and inhibitory circuits. Inter-train intervals (ITI) were initially incorporated into rTMS paradigms to avoid overheating and for safety considerations. Recent studies have shown that inclusion of ITI, as opposed to continuous stimulation, is essential for eliciting excitatory effects, but the optimal ITI remains unknown. Moreover, if ITI duration has no effect, it may be possible to substantially reduce treatment time for rTMS. ITI duration modulates the excitatory and disinhibitory effects of rTMS. rTMS (20 Hz, 2 s trains, 1200 pulses, 100% RMT) was applied in 14 healthy individuals with ITI of 4s (duration: ∼3 min), 8s (∼5 min), 16s (∼9 min) or 32s (16.5 min) in sessions separated by ≥5 days. Effects on cortical excitability and GABA A receptor mediated short interval intracortical inhibition (SICI) were measured for 75 min following rTMS. The time-course of increased cortical excitability following rTMS was independent of ITI duration. There was a striking influence of ITI on SICI, whereby disinhibition increased with shorter ITI duration. Changes in cortical excitability and SICI were independent of each other. These findings provide the first evidence to suggest that ITI may be substantially shortened without loss of rTMS effects, and warrant further investigation where rTMS is applied therapeutically. Furthermore, shorter ITIs result in greater disinhibitory effects which may be desirable in some clinical disorders and accelerated treatment paradigms. The tuning of the plasticity of cortical excitatory and inhibitory circuits to rTMS parameters in human cortex are independent. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Inhibition of the cluster of differentiation 14 innate immunity pathway with IAXO-101 improves chronic microelectrode performance

    Science.gov (United States)

    Hermann, John K.; Ravikumar, Madhumitha; Shoffstall, Andrew J.; Ereifej, Evon S.; Kovach, Kyle M.; Chang, Jeremy; Soffer, Arielle; Wong, Chun; Srivastava, Vishnupriya; Smith, Patrick; Protasiewicz, Grace; Jiang, Jingle; Selkirk, Stephen M.; Miller, Robert H.; Sidik, Steven; Ziats, Nicholas P.; Taylor, Dawn M.; Capadona, Jeffrey R.

    2018-04-01

    Objective. Neuroinflammatory mechanisms are hypothesized to contribute to intracortical microelectrode failures. The cluster of differentiation 14 (CD14) molecule is an innate immunity receptor involved in the recognition of pathogens and tissue damage to promote inflammation. The goal of the study was to investigate the effect of CD14 inhibition on intracortical microelectrode recording performance and tissue integration. Approach. Mice implanted with intracortical microelectrodes in the motor cortex underwent electrophysiological characterization for 16 weeks, followed by endpoint histology. Three conditions were examined: (1) wildtype control mice, (2) knockout mice lacking CD14, and (3) wildtype control mice administered a small molecule inhibitor to CD14 called IAXO-101. Main results. The CD14 knockout mice exhibited acute but not chronic improvements in intracortical microelectrode performance without significant differences in endpoint histology. Mice receiving IAXO-101 exhibited significant improvements in recording performance over the entire 16 week duration without significant differences in endpoint histology. Significance. Full removal of CD14 is beneficial at acute time ranges, but limited CD14 signaling is beneficial at chronic time ranges. Innate immunity receptor inhibition strategies have the potential to improve long-term intracortical microelectrode performance.

  4. Failure mode analysis of silicon-based intracortical microelectrode arrays in non-human primates

    Science.gov (United States)

    Barrese, James C.; Rao, Naveen; Paroo, Kaivon; Triebwasser, Corey; Vargas-Irwin, Carlos; Franquemont, Lachlan; Donoghue, John P.

    2013-12-01

    Objective. Brain-computer interfaces (BCIs) using chronically implanted intracortical microelectrode arrays (MEAs) have the potential to restore lost function to people with disabilities if they work reliably for years. Current sensors fail to provide reliably useful signals over extended periods of time for reasons that are not clear. This study reports a comprehensive retrospective analysis from a large set of implants of a single type of intracortical MEA in a single species, with a common set of measures in order to evaluate failure modes. Approach. Since 1996, 78 silicon MEAs were implanted in 27 monkeys (Macaca mulatta). We used two approaches to find reasons for sensor failure. First, we classified the time course leading up to complete recording failure as acute (abrupt) or chronic (progressive). Second, we evaluated the quality of electrode recordings over time based on signal features and electrode impedance. Failure modes were divided into four categories: biological, material, mechanical, and unknown. Main results. Recording duration ranged from 0 to 2104 days (5.75 years), with a mean of 387 days and a median of 182 days (n = 78). Sixty-two arrays failed completely with a mean time to failure of 332 days (median = 133 days) while nine array experiments were electively terminated for experimental reasons (mean = 486 days). Seven remained active at the close of this study (mean = 753 days). Most failures (56%) occurred within a year of implantation, with acute mechanical failures the most common class (48%), largely because of connector issues (83%). Among grossly observable biological failures (24%), a progressive meningeal reaction that separated the array from the parenchyma was most prevalent (14.5%). In the absence of acute interruptions, electrode recordings showed a slow progressive decline in spike amplitude, noise amplitude, and number of viable channels that predicts complete signal loss by about eight years. Impedance measurements showed

  5. Variations in response control within at-risk gamblers and non-gambling controls explained by GABAergic inhibition in the motor cortex.

    Science.gov (United States)

    Chowdhury, Nahian S; Livesey, Evan J; Blaszczynski, Alex; Harris, Justin A

    2018-03-17

    Paired-pulse Transcranial Magnetic Stimulation (TMS) is used to study inhibitory and excitatory mechanisms in the motor cortex through the measurement of short-interval intracortical inhibition (SICI), indicative of GABAergic activity, and intracortical facilitation (ICF), indicative of glutamatergic activity. In the present study, TMS was delivered to the left motor cortex of 40 participants while we measured SICI and ICF at rest. We were interested in whether variation between individuals in these modulatory mechanisms is related to inhibitory control over responding measured as stop signal reaction time (SSRT). Within the same group of participants, we investigated whether SICI, ICF, SSRT, and self-reported impulsivity, are impaired in participants identified as At-Risk gamblers (n = 20) compared to non-gambling controls (n = 20). We found a significant negative correlation between SICI strength and SSRT, but no correlation between ICF strength and SSRT after controlling for the correlation between SICI and SSRT. Thus, poor inhibitory control of responding was associated with weak GABAergic activity. When taking into account the effects of substance/alcohol use and attention-deficit hyperactivity disorder (ADHD) symptom severity, At-Risk gamblers showed elevated self-reported impulsivity, but did not differ from controls on SSRT or SICI/ICF. Our study is the first to show that individual differences in motor cortex inhibition can predict stopping performance, and the first to investigate paired-pulse TMS parameters (together with other impulse control measures) in a gambling population. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. Long-term stability of sensitivity to intracortical microstimulation of somatosensory cortex

    Science.gov (United States)

    Callier, Thierri; Schluter, Erik W.; Tabot, Gregg A.; Miller, Lee E.; Tenore, Francesco V.; Bensmaia, Sliman J.

    2015-10-01

    Objective. The dexterous manipulation of objects depends heavily on somatosensory signals from the limb. The development of anthropomorphic robotic arms and of algorithms to decode intended movements from neuronal signals has stimulated the need to restore somatosensation for use in upper-limb neuroprostheses. Without touch and proprioception, patients have difficulty controlling prosthetic limbs to a level that justifies the required invasive surgery. Intracortical microstimulation (ICMS) through chronically implanted electrode arrays has the potential to provide rich and intuitive sensory feedback. This approach to sensory restoration requires, however, that the evoked sensations remain stable over time. Approach. To investigate the stability of ICMS-evoked sensations, we measured the ability of non-human primates to detect ICMS over experimental sessions that spanned years. Main results. We found that the performance of the animals remained highly stable over time, even when they were tested with electrodes that had experienced extensive stimulation. Significance. Given the stability of the sensations that it evokes, ICMS may thus be a viable approach for sensory restoration.

  7. Brain computer interface learning for systems based on electrocorticography and intracortical microelectrode arrays.

    Science.gov (United States)

    Hiremath, Shivayogi V; Chen, Weidong; Wang, Wei; Foldes, Stephen; Yang, Ying; Tyler-Kabara, Elizabeth C; Collinger, Jennifer L; Boninger, Michael L

    2015-01-01

    A brain-computer interface (BCI) system transforms neural activity into control signals for external devices in real time. A BCI user needs to learn to generate specific cortical activity patterns to control external devices effectively. We call this process BCI learning, and it often requires significant effort and time. Therefore, it is important to study this process and develop novel and efficient approaches to accelerate BCI learning. This article reviews major approaches that have been used for BCI learning, including computer-assisted learning, co-adaptive learning, operant conditioning, and sensory feedback. We focus on BCIs based on electrocorticography and intracortical microelectrode arrays for restoring motor function. This article also explores the possibility of brain modulation techniques in promoting BCI learning, such as electrical cortical stimulation, transcranial magnetic stimulation, and optogenetics. Furthermore, as proposed by recent BCI studies, we suggest that BCI learning is in many ways analogous to motor and cognitive skill learning, and therefore skill learning should be a useful metaphor to model BCI learning.

  8. Early sensory experience influences the development of multisensory thalamocortical and intracortical connections of primary sensory cortices.

    Science.gov (United States)

    Henschke, Julia U; Oelschlegel, Anja M; Angenstein, Frank; Ohl, Frank W; Goldschmidt, Jürgen; Kanold, Patrick O; Budinger, Eike

    2018-04-01

    The nervous system integrates information from multiple senses. This multisensory integration already occurs in primary sensory cortices via direct thalamocortical and corticocortical connections across modalities. In humans, sensory loss from birth results in functional recruitment of the deprived cortical territory by the spared senses but the underlying circuit changes are not well known. Using tracer injections into primary auditory, somatosensory, and visual cortex within the first postnatal month of life in a rodent model (Mongolian gerbil) we show that multisensory thalamocortical connections emerge before corticocortical connections but mostly disappear during development. Early auditory, somatosensory, or visual deprivation increases multisensory connections via axonal reorganization processes mediated by non-lemniscal thalamic nuclei and the primary areas themselves. Functional single-photon emission computed tomography of regional cerebral blood flow reveals altered stimulus-induced activity and higher functional connectivity specifically between primary areas in deprived animals. Together, we show that intracortical multisensory connections are formed as a consequence of sensory-driven multisensory thalamocortical activity and that spared senses functionally recruit deprived cortical areas by an altered development of sensory thalamocortical and corticocortical connections. The functional-anatomical changes after early sensory deprivation have translational implications for the therapy of developmental hearing loss, blindness, and sensory paralysis and might also underlie developmental synesthesia.

  9. Brain Computer Interface Learning for Systems Based on Electrocorticography and Intracortical Microelectrode Arrays

    Directory of Open Access Journals (Sweden)

    Shivayogi V Hiremath

    2015-06-01

    Full Text Available A brain-computer interface (BCI system transforms neural activity into control signals for external devices in real time. A BCI user needs to learn to generate specific cortical activity patterns to control external devices effectively. We call this process BCI learning, and it often requires significant effort and time. Therefore, it is important to study this process and develop novel and efficient approaches to accelerate BCI learning. This article reviews major approaches that have been used for BCI learning, including computer-assisted learning, co-adaptive learning, operant conditioning, and sensory feedback. We focus on BCIs based on electrocorticography and intracortical microelectrode arrays for restoring motor function. This article also explores the possibility of brain modulation techniques in promoting BCI learning, such as electrical cortical stimulation, transcranial magnetic stimulation, and optogenetics. Furthermore, as proposed by recent BCI studies, we suggest that BCI learning is in many ways analogous to motor and cognitive skill learning, and therefore skill learning should be a useful metaphor to model BCI learning.

  10. Comparison of spike sorting and thresholding of voltage waveforms for intracortical brain-machine interface performance

    Science.gov (United States)

    Christie, Breanne P.; Tat, Derek M.; Irwin, Zachary T.; Gilja, Vikash; Nuyujukian, Paul; Foster, Justin D.; Ryu, Stephen I.; Shenoy, Krishna V.; Thompson, David E.; Chestek, Cynthia A.

    2015-02-01

    Objective. For intracortical brain-machine interfaces (BMIs), action potential voltage waveforms are often sorted to separate out individual neurons. If these neurons contain independent tuning information, this process could increase BMI performance. However, the sorting of action potentials (‘spikes’) requires high sampling rates and is computationally expensive. To explicitly define the difference between spike sorting and alternative methods, we quantified BMI decoder performance when using threshold-crossing events versus sorted action potentials. Approach. We used data sets from 58 experimental sessions from two rhesus macaques implanted with Utah arrays. Data were recorded while the animals performed a center-out reaching task with seven different angles. For spike sorting, neural signals were sorted into individual units by using a mixture of Gaussians to cluster the first four principal components of the waveforms. For thresholding events, spikes that simply crossed a set threshold were retained. We decoded the data offline using both a Naïve Bayes classifier for reaching direction and a linear regression to evaluate hand position. Main results. We found the highest performance for thresholding when placing a threshold between -3 and -4.5 × Vrms. Spike sorted data outperformed thresholded data for one animal but not the other. The mean Naïve Bayes classification accuracy for sorted data was 88.5% and changed by 5% on average when data were thresholded. The mean correlation coefficient for sorted data was 0.92, and changed by 0.015 on average when thresholded. Significance. For prosthetics applications, these results imply that when thresholding is used instead of spike sorting, only a small amount of performance may be lost. The utilization of threshold-crossing events may significantly extend the lifetime of a device because these events are often still detectable once single neurons are no longer isolated.

  11. Behavioral detection of intra-cortical microstimulation in the primary and secondary auditory cortex of cats

    Directory of Open Access Journals (Sweden)

    Zhenling eZhao

    2015-04-01

    Full Text Available Although neural responses to sound stimuli have been thoroughly investigated in various areas of the auditory cortex, the results electrophysiological recordings cannot establish a causal link between neural activation and brain function. Electrical microstimulation, which can selectively perturb neural activity in specific parts of the nervous system, is an important tool for exploring the organization and function of brain circuitry. To date, the studies describing the behavioral effects of electrical stimulation have largely been conducted in the primary auditory cortex. In this study, to investigate the potential differences in the effects of electrical stimulation on different cortical areas, we measured the behavioral performance of cats in detecting intra-cortical microstimulation (ICMS delivered in the primary and secondary auditory fields (A1 and A2, respectively. After being trained to perform a Go/No-Go task cued by sounds, we found that cats could also learn to perform the task cued by ICMS; furthermore, the detection of the ICMS was similarly sensitive in A1 and A2. Presenting wideband noise together with ICMS substantially decreased the performance of cats in detecting ICMS in A1 and A2, consistent with a noise masking effect on the sensation elicited by the ICMS. In contrast, presenting ICMS with pure-tones in the spectral receptive field of the electrode-implanted cortical site reduced ICMS detection performance in A1 but not A2. Therefore, activation of A1 and A2 neurons may produce different qualities of sensation. Overall, our study revealed that ICMS-induced neural activity could be easily integrated into an animal’s behavioral decision process and had an implication for the development of cortical auditory prosthetics.

  12. High performance communication by people with paralysis using an intracortical brain-computer interface.

    Science.gov (United States)

    Pandarinath, Chethan; Nuyujukian, Paul; Blabe, Christine H; Sorice, Brittany L; Saab, Jad; Willett, Francis R; Hochberg, Leigh R; Shenoy, Krishna V; Henderson, Jaimie M

    2017-02-21

    Brain-computer interfaces (BCIs) have the potential to restore communication for people with tetraplegia and anarthria by translating neural activity into control signals for assistive communication devices. While previous pre-clinical and clinical studies have demonstrated promising proofs-of-concept (Serruya et al., 2002; Simeral et al., 2011; Bacher et al., 2015; Nuyujukian et al., 2015; Aflalo et al., 2015; Gilja et al., 2015; Jarosiewicz et al., 2015; Wolpaw et al., 1998; Hwang et al., 2012; Spüler et al., 2012; Leuthardt et al., 2004; Taylor et al., 2002; Schalk et al., 2008; Moran, 2010; Brunner et al., 2011; Wang et al., 2013; Townsend and Platsko, 2016; Vansteensel et al., 2016; Nuyujukian et al., 2016; Carmena et al., 2003; Musallam et al., 2004; Santhanam et al., 2006; Hochberg et al., 2006; Ganguly et al., 2011; O'Doherty et al., 2011; Gilja et al., 2012), the performance of human clinical BCI systems is not yet high enough to support widespread adoption by people with physical limitations of speech. Here we report a high-performance intracortical BCI (iBCI) for communication, which was tested by three clinical trial participants with paralysis. The system leveraged advances in decoder design developed in prior pre-clinical and clinical studies (Gilja et al., 2015; Kao et al., 2016; Gilja et al., 2012). For all three participants, performance exceeded previous iBCIs (Bacher et al., 2015; Jarosiewicz et al., 2015) as measured by typing rate (by a factor of 1.4-4.2) and information throughput (by a factor of 2.2-4.0). This high level of performance demonstrates the potential utility of iBCIs as powerful assistive communication devices for people with limited motor function.Clinical Trial No: NCT00912041.

  13. The effect of chronic intracortical microstimulation on the electrode-tissue interface

    Science.gov (United States)

    Chen, Kevin H.; Dammann, John F.; Boback, Jessica L.; Tenore, Francesco V.; Otto, Kevin J.; Gaunt, Robert A.; Bensmaia, Sliman J.

    2014-04-01

    Objective. Somatosensation is critical for effective object manipulation, but current upper limb prostheses do not provide such feedback to the user. For individuals who require use of prosthetic limbs, this lack of feedback transforms a mundane task into one that requires extreme concentration and effort. Although vibrotactile motors and sensory substitution devices can be used to convey gross sensations, a direct neural interface is required to provide detailed and intuitive sensory feedback. The viability of intracortical microstimulation (ICMS) as a method to deliver feedback depends in part on the long-term reliability of implanted electrodes used to deliver the stimulation. The objective of the present study is to investigate the effects of chronic ICMS on the electrode-tissue interface. Approach. We stimulate the primary somatosensory cortex of three Rhesus macaques through chronically implanted electrodes for 4 h per day over a period of six months, with different electrodes subjected to different regimes of stimulation. We measure the impedance and voltage excursion as a function of time and of ICMS parameters. We also test the sensorimotor consequences of chronic ICMS by having animals grasp and manipulate small treats. Main results. We show that impedance and voltage excursion both decay with time but stabilize after 10-12 weeks. The magnitude of this decay is dependent on the amplitude of the ICMS and, to a lesser degree, the duration of individual pulse trains. Furthermore, chronic ICMS does not produce any deficits in fine motor control. Significance. The results suggest that chronic ICMS has only a minor effect on the electrode-tissue interface and may thus be a viable means to convey sensory feedback in neuroprosthetics.

  14. A fast intracortical brain-machine interface with patterned optogenetic feedback.

    Science.gov (United States)

    Abbasi, Aamir; Goueytes, Dorian; Shulz, Daniel E; Ego-Stengel, Valerie; Estebanez, Luc

    2018-04-04

    The development of brain-machine interfaces (BMIs) brings a new perspective to patients with a loss of autonomy. By combining online recordings of brain activity with a decoding algorithm, patients can learn to control a robotic arm in order to perform simple actions. However, in contrast to the vast amounts of somatosensory information channeled by limbs to the brain, current BMIs are devoid of touch and force sensors. Patients must therefore rely solely on vision and audition, which are maladapted to the control of a prosthesis. In contrast, in a healthy limb, somatosensory inputs alone can efficiently guide the handling of a fragile object, or ensure a smooth trajectory. We have developed a BMI in the mouse that includes a rich artificial somatosensory-like cortical feedback. Our setup includes online recordings of the activity of multiple neurons in the whisker primary motor cortex (vM1), and delivers feedback simultaneously via a low-latency, high-refresh rate and spatially structured photo-stimulation of the whisker primary somatosensory cortex (vS1), based on a mapping obtained by intrinsic imaging. We demonstrate the operation of the loop and show that mice can detect the neuronal spiking in vS1 triggered by the photo-stimulations. Finally, we show that the mice can learn a behavioral task relying only on the artificial inputs and outputs of the closed-loop BMI. This is the first motor BMI that includes a short-latency, intracortical, somatosensory-like feedback. It will be a useful platform to discover efficient cortical feedback schemes towards future human BMI applications. Creative Commons Attribution license.

  15. Computational modeling of direct neuronal recruitment during intracortical microstimulation in somatosensory cortex

    Science.gov (United States)

    Overstreet, C. K.; Klein, J. D.; Helms Tillery, S. I.

    2013-12-01

    Objective. Electrical stimulation of cortical tissue could be used to deliver sensory information as part of a neuroprosthetic device, but current control of the location, resolution, quality, and intensity of sensations elicited by intracortical microstimulation (ICMS) remains inadequate for this purpose. One major obstacle to resolving this problem is the poor understanding of the neural activity induced by ICMS. Even with new imaging methods, quantifying the activity of many individual neurons within cortex is difficult. Approach. We used computational modeling to examine the response of somatosensory cortex to ICMS. We modeled the axonal arbors of eight distinct morphologies of interneurons and seven types of pyramidal neurons found in somatosensory cortex and identified their responses to extracellular stimulation. We then combined these axonal elements to form a multi-layered slab of simulated cortex and investigated the patterns of neural activity directly induced by ICMS. Specifically we estimated the number, location, and variety of neurons directly recruited by stimulation on a single penetrating microelectrode. Main results. The population of neurons activated by ICMS was dependent on both stimulation strength and the depth of the electrode within cortex. Strikingly, stimulation recruited interneurons and pyramidal neurons in very different patterns. Interneurons are primarily recruited within a dense, continuous region around the electrode, while pyramidal neurons were recruited in a sparse fashion both near the electrode and up to several millimeters away. Thus ICMS can lead to an unexpectedly complex spatial distribution of firing neurons. Significance. These results lend new insights to the complexity and range of neural activity that can be induced by ICMS. This work also suggests mechanisms potentially responsible for the inconsistency and unnatural quality of sensations initiated by ICMS. Understanding these mechanisms will aid in the design of

  16. Psychophysical correspondence between vibrotactile intensity and intracortical microstimulation for tactile neuroprostheses in rats

    Science.gov (United States)

    Devecioğlu, İsmail; Güçlü, Burak

    2017-02-01

    Objective. Recent studies showed that intracortical microstimulation (ICMS) generates artificial sensations which can be utilized as somatosensory feedback in cortical neuroprostheses. To mimic the natural psychophysical response, ICMS parameters are modulated according to psychometric equivalence functions (PEFs). PEFs match the intensity levels of ICMS and mechanical stimuli, which elicit equal detection probabilities, but they typically do not include the frequency as a control variable. We aimed to establish frequency-dependent PEFs for vibrotactile stimulation of the glabrous skin and ICMS in the primary somatosensory cortex of awake freely behaving rats. Approach. We collected psychometric data for vibrotactile and ICMS detection at three stimulation frequencies (40, 60 and 80 Hz). The psychometric data were fitted with a model equation of two independent variables (stimulus intensity and frequency) and four subject-dependent parameters. For each rat, we constructed a separate PEF which was used to estimate the ICMS current amplitude for a given displacement amplitude and frequency. The ICMS frequency was set equal to the vibrotactile frequency. We validated the PEFs in a modified task which included randomly selected probe trials presented either with a vibrotactile or an ICMS stimulus, and also at frequencies and intensity levels not tested before. Main results. The PEFs were generally successful in estimating the ICMS current intensities (no significant differences between vibrotactile and ICMS trials in Kolmogorov-Smirnov tests). Specifically, hit rates from both trial conditions were significantly correlated in 86% of the cases, and 52% of all data had perfect match in linear regression. Significance. The psychometric correspondence model presented in this study was constructed based on surface functions which define psychophysical detection probability as a function of stimulus intensity and frequency. Therefore, it may be used for the real

  17. Linear distributed source modeling of local field potentials recorded with intra-cortical electrode arrays.

    Directory of Open Access Journals (Sweden)

    Rikkert Hindriks

    Full Text Available Planar intra-cortical electrode (Utah arrays provide a unique window into the spatial organization of cortical activity. Reconstruction of the current source density (CSD underlying such recordings, however, requires "inverting" Poisson's equation. For inter-laminar recordings, this is commonly done by the CSD method, which consists in taking the second-order spatial derivative of the recorded local field potentials (LFPs. Although the CSD method has been tremendously successful in mapping the current generators underlying inter-laminar LFPs, its application to planar recordings is more challenging. While for inter-laminar recordings the CSD method seems reasonably robust against violations of its assumptions, is it unclear as to what extent this holds for planar recordings. One of the objectives of this study is to characterize the conditions under which the CSD method can be successfully applied to Utah array data. Using forward modeling, we find that for spatially coherent CSDs, the CSD method yields inaccurate reconstructions due to volume-conducted contamination from currents in deeper cortical layers. An alternative approach is to "invert" a constructed forward model. The advantage of this approach is that any a priori knowledge about the geometrical and electrical properties of the tissue can be taken into account. Although several inverse methods have been proposed for LFP data, the applicability of existing electroencephalographic (EEG and magnetoencephalographic (MEG inverse methods to LFP data is largely unexplored. Another objective of our study therefore, is to assess the applicability of the most commonly used EEG/MEG inverse methods to Utah array data. Our main conclusion is that these inverse methods provide more accurate CSD reconstructions than the CSD method. We illustrate the inverse methods using event-related potentials recorded from primary visual cortex of a macaque monkey during a motion discrimination task.

  18. Changes in intracortical microporosities induced by pharmaceutical treatment of osteoporosis as detected by high resolution micro-CT

    Energy Technology Data Exchange (ETDEWEB)

    Tommasini S. M.; Miller L.; Trinward, A.; Acerbo, A.S.; De Carlo F. and Judex, S.

    2011-12-28

    Bone's microporosities play important biologic and mechanical roles. Here, we quantified 3D changes in cortical osteocyte-lacunae and other small porosities induced by estrogen withdrawal and two different osteoporosistreatments. Unlike 2D measurements, these data collected via synchrotron radiation-based {mu}CT describe the size and 3D spatial distribution of a large number of porous structures. Six-month old female Sprague-Dawley rats were separated into four groups of age-matched controls, untreated OVX, OVX treated with PTH, and OVX treated with Alendronate (ALN). Intracortical microporosity of the medial quadrant of the femoral diaphysis was quantified at endosteal, intracortical, and periosteal regions of the samples, allowing the quantification of osteocyte lacunae that were formed primarily before versus after the start of treatment. Across the overall thickness of the medial cortex, lacunar volume fraction (Lc.V/TV) was significantly lower in ALN treated rats compared to PTH. In the endosteal region, average osteocyte lacunar volume (< Lc.V >) of untreated OVX rats was significantly lower than in age-matched controls, indicating a decrease in osteocyte lacunar size in bone formed on the endosteal surface after estrogen withdrawal. The effect of treatment (OVX, ALN, PTH) on the number of lacunae per tissue volume (Lc.N/TV) was dependent on the specific location within the cortex (endosteal, intracortical, periosteal). In both the endosteal and intracortical regions, Lc.N/TV was significantly lower in ALN than in untreated OVX, suggesting a site-specific effect in osteocyte lacuna density with ALN treatment. There also were a significantly greater number of small pores (5-100 {micro}m{sup 3} in volume) in the endosteal region for PTH compared to ALN. The mechanical impact of this altered microporosity structure is unknown, but might serve to enhance, rather than deteriorate bone strength with PTH treatment, as smaller osteocyte lacunae may be better

  19. Reduced diaphyseal strength associated with high intracortical vascular porosity within long bones of children with osteogenesis imperfecta.

    Science.gov (United States)

    Albert, Carolyne; Jameson, John; Smith, Peter; Harris, Gerald

    2014-09-01

    Osteogenesis imperfecta is a genetic disorder resulting in bone fragility. The mechanisms behind this fragility are not well understood. In addition to characteristic bone mass deficiencies, research suggests that bone material properties are compromised in individuals with this disorder. However, little data exists regarding bone properties beyond the microstructural scale in individuals with this disorder. Specimens were obtained from long bone diaphyses of nine children with osteogenesis imperfecta during routine osteotomy procedures. Small rectangular beams, oriented longitudinally and transversely to the diaphyseal axis, were machined from these specimens and elastic modulus, yield strength, and maximum strength were measured in three-point bending. Intracortical vascular porosity, bone volume fraction, osteocyte lacuna density, and volumetric tissue mineral density were determined by synchrotron micro-computed tomography, and relationships among these mechanical properties and structural parameters were explored. Modulus and strength were on average 64-68% lower in the transverse vs. longitudinal beams (Posteogenesis imperfecta. Results confirm that these properties are anisotropic. Elevated vascular porosity was observed in most specimens, and this parameter was associated with reduced bone material strength. These results offer insight toward understanding bone fragility and the role of intracortical porosity on the strength of bone tissue in children with osteogenesis imperfecta. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Convex Interval Games

    NARCIS (Netherlands)

    Alparslan-Gok, S.Z.; Brânzei, R.; Tijs, S.H.

    2008-01-01

    In this paper, convex interval games are introduced and some characterizations are given. Some economic situations leading to convex interval games are discussed. The Weber set and the Shapley value are defined for a suitable class of interval games and their relations with the interval core for

  1. Cooperative interval games

    OpenAIRE

    Bok, Jan

    2014-01-01

    In this thesis, we study cooperative interval games, a generalized model of cooperative games in which worth of every coalition corresponds with a closed interval representing all possible outcomes of their cooperation. We give a brief introduction into classical cooperative games, interval analysis and finally introduction to cooperative interval games with focus on selections, that is on all possible outcomes of interval game with no additional uncertainty. We introduce new selection-based ...

  2. Interval Temporal Logics

    DEFF Research Database (Denmark)

    Monica, Dario Della; Goranko, Valentin; Montanari, Angelo

    2011-01-01

    We discuss a family of modal logics for reasoning about relational structures of intervals over (usually) linear orders, with modal operators associated with the various binary relations between such intervals, known as Allen’s interval relations. The formulae of these logics are evaluated...... at intervals rather than points and the main eect of that semantic feature is substantially higher expressiveness and computational complexity of the interval logics as compared to point-based ones. Without purporting to provide a comprehensive survey of the field, we take the reader to a journey through...... the main developments in it over the past 10 years and outline some landmark results on expressiveness and (un)decidability of the satisfiability problem for the family of interval logics....

  3. Estimating duration intervals

    NARCIS (Netherlands)

    Ph.H.B.F. Franses (Philip Hans); B.L.K. Vroomen (Björn)

    2003-01-01

    textabstractDuration intervals measure the dynamic impact of advertising on sales. More precise, the p per cent duration interval measures the time lag between the advertising impulse and the moment that p per cent of its effect has decayed. In this paper, we derive an expression for the duration

  4. Age-related mapping of intracortical myelin from late adolescence to middle adulthood using T1-weighted MRI.

    Science.gov (United States)

    Rowley, Christopher D; Sehmbi, Manpreet; Bazin, Pierre-Louis; Tardif, Christine L; Minuzzi, Luciano; Frey, Benicio N; Bock, Nicholas A

    2017-04-30

    Magnetic resonance imaging (MRI) studies in humans have reported that the T 1 -weighted signal in the cerebral cortex follows an inverted "U" trajectory over the lifespan. Here, we investigated the T 1 -weighted signal trajectory from late adolescence to middle adulthood in humans to characterize the age range when mental illnesses tend to present, and efficacy of treatments are evaluated. We compared linear to quadratic predictors of age on signal in 67 healthy individuals, 17-45 years old. We investigated ¼, ½, and ¾ depths in the cortex representing intracortical myelin (ICM), in the superficial white matter (SWM), and in a reference deep white matter tract. We found that the quadratic fit was superior in all regions of the cortex, while signal in the SWM and deep white matter showed no global dependence on age over this range. The signal trajectory in any region followed a similar shape regardless of cortical depth. The quadratic fit was analyzed in 70 cortical regions to obtain the age of maximum signal intensity. We found that visual, cingulate, and left ventromedial prefrontal cortices peak first around 34 years old, whereas motor and premotor areas peak latest at ∼38 years. Our analysis suggests that ICM trajectories over this range can be modeled well in small cohorts of subjects using quadratic functions, which are amenable to statistical analysis, thus suitable for investigating regional changes in ICM with disease. This study highlights a novel approach to map ICM trajectories using an age range that coincides with the onset of many mental illnesses. Hum Brain Mapp, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  5. Inter-Pregnancy Interval

    African Journals Online (AJOL)

    Buchi

    This definition excludes. 1, 2 miscarriage as a preceding pregnancy event. Often the IPI is calculated as ... Inter-pregnancy interval of <6 months was significantly associated with an increased risk of adverse subsequent pregnancy outcomes. Mothers 35 years or older at start of childbearing have the highest risk compared to.

  6. Interval methods: An introduction

    DEFF Research Database (Denmark)

    Achenie, L.E.K.; Kreinovich, V.; Madsen, Kaj

    2006-01-01

    This chapter contains selected papers presented at the Minisymposium on Interval Methods of the PARA'04 Workshop '' State-of-the-Art in Scientific Computing ''. The emphasis of the workshop was on high-performance computing (HPC). The ongoing development of ever more advanced computers provides...

  7. Applications of interval computations

    CERN Document Server

    Kreinovich, Vladik

    1996-01-01

    Primary Audience for the Book • Specialists in numerical computations who are interested in algorithms with automatic result verification. • Engineers, scientists, and practitioners who desire results with automatic verification and who would therefore benefit from the experience of suc­ cessful applications. • Students in applied mathematics and computer science who want to learn these methods. Goal Of the Book This book contains surveys of applications of interval computations, i. e. , appli­ cations of numerical methods with automatic result verification, that were pre­ sented at an international workshop on the subject in EI Paso, Texas, February 23-25, 1995. The purpose of this book is to disseminate detailed and surveyed information about existing and potential applications of this new growing field. Brief Description of the Papers At the most fundamental level, interval arithmetic operations work with sets: The result of a single arithmetic operation is the set of all possible results as the o...

  8. Interval orders and reverse mathematics

    OpenAIRE

    Marcone, Alberto

    2006-01-01

    We study the reverse mathematics of interval orders. We establish the logical strength of the implications between various definitions of the notion of interval order. We also consider the strength of different versions of the characterization theorem for interval orders: a partial order is an interval order if and only if it does not contain $2 \\oplus 2$. We also study proper interval orders and their characterization theorem: a partial order is a proper interval order if and only if it cont...

  9. Chaos on the interval

    CERN Document Server

    Ruette, Sylvie

    2017-01-01

    The aim of this book is to survey the relations between the various kinds of chaos and related notions for continuous interval maps from a topological point of view. The papers on this topic are numerous and widely scattered in the literature; some of them are little known, difficult to find, or originally published in Russian, Ukrainian, or Chinese. Dynamical systems given by the iteration of a continuous map on an interval have been broadly studied because they are simple but nevertheless exhibit complex behaviors. They also allow numerical simulations, which enabled the discovery of some chaotic phenomena. Moreover, the "most interesting" part of some higher-dimensional systems can be of lower dimension, which allows, in some cases, boiling it down to systems in dimension one. Some of the more recent developments such as distributional chaos, the relation between entropy and Li-Yorke chaos, sequence entropy, and maps with infinitely many branches are presented in book form for the first time. The author gi...

  10. Interval Female Sterilization.

    Science.gov (United States)

    Stuart, Gretchen S; Ramesh, Shanthi S

    2018-01-01

    Female sterilization is relied on by nearly one in three women aged 35-44 years in the United States. Sterilization procedures are among the most common procedures that obstetrician-gynecologists perform. The most frequent sterilization procedures include postpartum tubal ligation, laparoscopic tubal disruption or salpingectomy, and hysteroscopic tubal occlusion. The informed consent process for sterilization is crucial and requires shared decision-making between the patient and the health care provider. Counseling should include the specific risks and benefits of the specific surgical approaches. Additionally, women should be counseled on the alternatives to sterilization, including intrauterine contraceptives and subdermal contraceptive implants. Complications, including unplanned pregnancy after successful female sterilization, are rare. The objectives of this Clinical Expert Series are to describe the epidemiology of female sterilization, access to postpartum sterilization, advances in interval sterilization techniques, and clinical considerations in caring for women requesting sterilization.

  11. Multichannel interval timer

    International Nuclear Information System (INIS)

    Turko, B.T.

    1983-10-01

    A CAMAC based modular multichannel interval timer is described. The timer comprises twelve high resolution time digitizers with a common start enabling twelve independent stop inputs. Ten time ranges from 2.5 μs to 1.3 μs can be preset. Time can be read out in twelve 24-bit words either via CAMAC Crate Controller or an external FIFO register. LSB time calibration is 78.125 ps. An additional word reads out the operational status of twelve stop channels. The system consists of two modules. The analog module contains a reference clock and 13 analog time stretchers. The digital module contains counters, logic and interface circuits. The timer has an excellent differential linearity, thermal stability and crosstalk free performance

  12. Interval by interval analysis of commercial drilling speed

    Energy Technology Data Exchange (ETDEWEB)

    Dublenich, L.B.; Gor' kov, A.P.

    1984-01-01

    The results are cited of an interval by interval analysis of the commercial drilling speeds in individual sites of the Carpathian region (Skhodnitsa, Dolina, Duvboshanka) which attest to the presence of reserves for increasing the commercial drilling speeds.

  13. Resistive and reactive changes to the impedance of intracortical microelectrodes can be mitigated with polyethylene glycol under acute in vitro and in vivo settings

    Directory of Open Access Journals (Sweden)

    Salah eSommakia

    2014-08-01

    Full Text Available The reactive response of brain tissue to implantable intracortical microelectrodes is thought to negatively affect their recordable signal quality and impedance, resulting in unreliable longitudinal performance. The relationship between the progression of the reactive tissue into a glial scar and the decline in device performance is unclear. We show that exposure to a model protein solution in vitro and acute implantation result in both resistive and capacitive changes to electrode impedance, rather than purely resistive changes. We also show that applying 4000 MW polyethylene glycol (PEG prevents impedance increases in vitro, and reduces the percent change in impedance in vivo following implantation. Our results highlight the importance of considering the contributions of non-cellular components to the decline in neural microelectrode performance, and present a proof of concept for using a simple dip-coated PEG film to modulate changes in microelectrode impedance.

  14. Cortical inhibition reduces information redundancy at presentation of communication sounds in the primary auditory cortex.

    Science.gov (United States)

    Gaucher, Quentin; Huetz, Chloé; Gourévitch, Boris; Edeline, Jean-Marc

    2013-06-26

    In all sensory modalities, intracortical inhibition shapes the functional properties of cortical neurons but also influences the responses to natural stimuli. Studies performed in various species have revealed that auditory cortex neurons respond to conspecific vocalizations by temporal spike patterns displaying a high trial-to-trial reliability, which might result from precise timing between excitation and inhibition. Studying the guinea pig auditory cortex, we show that partial blockage of GABAA receptors by gabazine (GBZ) application (10 μm, a concentration that promotes expansion of cortical receptive fields) increased the evoked firing rate and the spike-timing reliability during presentation of communication sounds (conspecific and heterospecific vocalizations), whereas GABAB receptor antagonists [10 μm saclofen; 10-50 μm CGP55845 (p-3-aminopropyl-p-diethoxymethyl phosphoric acid)] had nonsignificant effects. Computing mutual information (MI) from the responses to vocalizations using either the evoked firing rate or the temporal spike patterns revealed that GBZ application increased the MI derived from the activity of single cortical site but did not change the MI derived from population activity. In addition, quantification of information redundancy showed that GBZ significantly increased redundancy at the population level. This result suggests that a potential role of intracortical inhibition is to reduce information redundancy during the processing of natural stimuli.

  15. [Transcranial magnetic stimulation (TMS), inhibition processes and attention deficit/hyperactivity disorder (ADHD) - an overview].

    Science.gov (United States)

    Hoegl, Thomas; Bender, Stephan; Buchmann, Johannes; Kratz, Oliver; Moll, Gunther H; Heinrich, Hartmut

    2014-11-01

    Motor system excitability can be tested by transcranial magnetic stimulation CFMS). In this article, an overview of recent methodological developments and research findings related to attention deficit/hyperactivity disorder (ADHD) is provided. Different TMS parameters that reflect the function of interneurons in the motor cortex may represent neurophysiological markers of inhibition in ADHD, particularly the so-called intracortical inhibition. In children with a high level of hyperactivity and impulsivity, intracortical inhibition was comparably low at rest as shortly before the execution of a movement. TMS-evoked potentials can also be measured in the EEG so that investigating processes of excitability is not restricted to motor areas in future studies. The effects of methylphenidate on motor system excitability may be interpreted in the sense of a 'fine-tuning' with these mainly dopaminergic effects also depending on genetic parameters (DAT1 transporter). A differentiated view on the organization of motor control can be achieved by a combined analysis of TMS parameters and event-related potentials. Applying this bimodal approach, strong evidence for a deviant implementation of motor control in children with ADHD and probably compensatory mechanisms (with involvement of the prefrontal cortex) was obtained. These findings, which contribute to a better understanding of hyperactivity/impulsivity, inhibitory processes and motor control in ADHD as well as the mechanisms of medication, underline the relevance of TMS as a neurophysiological method in ADHD research.

  16. Coverage Probability of Random Intervals

    OpenAIRE

    Chen, Xinjia

    2007-01-01

    In this paper, we develop a general theory on the coverage probability of random intervals defined in terms of discrete random variables with continuous parameter spaces. The theory shows that the minimum coverage probabilities of random intervals with respect to corresponding parameters are achieved at discrete finite sets and that the coverage probabilities are continuous and unimodal when parameters are varying in between interval endpoints. The theory applies to common important discrete ...

  17. Support Vector Regression with Interval-Input Interval-Output

    Directory of Open Access Journals (Sweden)

    Wensen An

    2008-12-01

    Full Text Available Support vector machines (classification and regression are powerful machine learning techniques for crisp data. In this paper, the problem is considered for interval data. Two methods to deal with the problem using support vector regression are proposed and two new methods for evaluating performance for estimating prediction interval are presented as well.

  18. Interval Entropy and Informative Distance

    Directory of Open Access Journals (Sweden)

    Fakhroddin Misagh

    2012-03-01

    Full Text Available The Shannon interval entropy function as a useful dynamic measure of uncertainty for two sided truncated random variables has been proposed in the literature of reliability. In this paper, we show that interval entropy can uniquely determine the distribution function. Furthermore, we propose a measure of discrepancy between two lifetime distributions at the interval of time in base of Kullback-Leibler discrimination information. We study various properties of this measure, including its connection with residual and past measures of discrepancy and interval entropy, and we obtain its upper and lower bounds.

  19. Automatic Error Analysis Using Intervals

    Science.gov (United States)

    Rothwell, E. J.; Cloud, M. J.

    2012-01-01

    A technique for automatic error analysis using interval mathematics is introduced. A comparison to standard error propagation methods shows that in cases involving complicated formulas, the interval approach gives comparable error estimates with much less effort. Several examples are considered, and numerical errors are computed using the INTLAB…

  20. Neural control of cursor trajectory and click by a human with tetraplegia 1000 days after implant of an intracortical microelectrode array

    Science.gov (United States)

    Simeral, J. D.; Kim, S.-P.; Black, M. J.; Donoghue, J. P.; Hochberg, L. R.

    2011-04-01

    The ongoing pilot clinical trial of the BrainGate neural interface system aims in part to assess the feasibility of using neural activity obtained from a small-scale, chronically implanted, intracortical microelectrode array to provide control signals for a neural prosthesis system. Critical questions include how long implanted microelectrodes will record useful neural signals, how reliably those signals can be acquired and decoded, and how effectively they can be used to control various assistive technologies such as computers and robotic assistive devices, or to enable functional electrical stimulation of paralyzed muscles. Here we examined these questions by assessing neural cursor control and BrainGate system characteristics on five consecutive days 1000 days after implant of a 4 × 4 mm array of 100 microelectrodes in the motor cortex of a human with longstanding tetraplegia subsequent to a brainstem stroke. On each of five prospectively-selected days we performed time-amplitude sorting of neuronal spiking activity, trained a population-based Kalman velocity decoding filter combined with a linear discriminant click state classifier, and then assessed closed-loop point-and-click cursor control. The participant performed both an eight-target center-out task and a random target Fitts metric task which was adapted from a human-computer interaction ISO standard used to quantify performance of computer input devices. The neural interface system was further characterized by daily measurement of electrode impedances, unit waveforms and local field potentials. Across the five days, spiking signals were obtained from 41 of 96 electrodes and were successfully decoded to provide neural cursor point-and-click control with a mean task performance of 91.3% ± 0.1% (mean ± s.d.) correct target acquisition. Results across five consecutive days demonstrate that a neural interface system based on an intracortical microelectrode array can provide repeatable, accurate point

  1. Observation-execution matching and action inhibition in human primary motor cortex during viewing of speech-related lip movements or listening to speech.

    Science.gov (United States)

    Murakami, Takenobu; Restle, Julia; Ziemann, Ulf

    2011-06-01

    One influential theory posits that language has evolved from gestural communication through observation-execution matching processes in the mirror neuron system (MNS). This theory predicts that observation of speech-related lip movements or even listening to speech would result in effector and task specific increase of the excitability of the corresponding motor representations in the primary motor cortex (M1), since actual movement execution is known be effector and task specific. In addition, effector and task specific inhibitory control mechanisms should be important to prevent overt motor activation during observation of speech-related lip movements or listening to speech. We tested these predictions by applying focal transcranial magnetic stimulation to the left M1 of 12 healthy right-handed volunteers and measuring motor evoked potentials (MEPs) and short-interval intracortical inhibition (SICI) in a lip muscle, the right orbicularis oris (OO), vs. a hand muscle, the right first dorsal interosseus (FDI). We found that MEP and SICI increased only in the OO but not in the FDI during viewing of speech-related lip movements or listening to speech. These changes were highly task specific because they were absent when lip movements non-related to speech were viewed. Finally, the increase in MEP amplitude in the OO correlated inversely with accuracy of speech perception, i.e. the MEP increase was directly related to task difficulty. The MEP findings support the notion that observation-execution matching is an operating process in the putative human MNS that might have been fundamental for evolution of language. Furthermore, the SICI findings provide evidence that inhibitory mechanisms are recruited to prevent unwanted overt motor activation during action observation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Neural Activity during Voluntary Movements in Each Body Representation of the Intracortical Microstimulation-Derived Map in the Macaque Motor Cortex.

    Science.gov (United States)

    Higo, Noriyuki; Kunori, Nobuo; Murata, Yumi

    2016-01-01

    In order to accurately interpret experimental data using the topographic body map identified by conventional intracortical microstimulation (ICMS), it is important to know how neurons in each division of the map respond during voluntary movements. Here we systematically investigated neuronal responses in each body representation of the ICMS map during a reach-grasp-retrieval task that involves the movements of multiple body parts. The topographic body map in the primary motor cortex (M1) generally corresponds to functional divisions of voluntary movements; neurons at the recording sites in each body representation with movement thresholds of 10 μA or less were differentially activated during the task, and the timing of responses was consistent with the movements of the body part represented. Moreover, neurons in the digit representation responded differently for the different types of grasping. In addition, the present study showed that neural activity depends on the ICMS current threshold required to elicit body movements and the location of the recording on the cortical surface. In the ventral premotor cortex (PMv), no correlation was found between the response properties of neurons and the body representation in the ICMS map. Neural responses specific to forelimb movements were often observed in the rostral part of PMv, including the lateral bank of the lower arcuate limb, in which ICMS up to 100 μA evoked no detectable movement. These results indicate that the physiological significance of the ICMS-derived maps is different between, and even within, areas M1 and PMv.

  3. Inverse Interval Matrix: A Survey

    Czech Academy of Sciences Publication Activity Database

    Rohn, Jiří; Farhadsefat, R.

    2011-01-01

    Roč. 22, - (2011), s. 704-719 E-ISSN 1081-3810 R&D Projects: GA ČR GA201/09/1957; GA ČR GC201/08/J020 Institutional research plan: CEZ:AV0Z10300504 Keywords : interval matrix * inverse interval matrix * NP-hardness * enclosure * unit midpoint * inverse sign stability * nonnegative invertibility * absolute value equation * algorithm Subject RIV: BA - General Mathematics Impact factor: 0.808, year: 2010 http://www.math.technion.ac.il/iic/ela/ela-articles/articles/vol22_pp704-719.pdf

  4. Haemostatic reference intervals in pregnancy

    DEFF Research Database (Denmark)

    Szecsi, Pal Bela; Jørgensen, Maja; Klajnbard, Anna

    2010-01-01

    Haemostatic reference intervals are generally based on samples from non-pregnant women. Thus, they may not be relevant to pregnant women, a problem that may hinder accurate diagnosis and treatment of haemostatic disorders during pregnancy. In this study, we establish gestational age......-specific reference intervals for coagulation tests during normal pregnancy. Eight hundred one women with expected normal pregnancies were included in the study. Of these women, 391 had no complications during pregnancy, vaginal delivery, or postpartum period. Plasma samples were obtained at gestational weeks 13...

  5. Robust misinterpretation of confidence intervals

    NARCIS (Netherlands)

    Hoekstra, Rink; Morey, Richard; Rouder, Jeffrey N.; Wagenmakers, Eric-Jan

    2014-01-01

    Null hypothesis significance testing (NHST) is undoubtedly the most common inferential technique used to justify claims in the social sciences. However, even staunch defenders of NHST agree that its outcomes are often misinterpreted. Confidence intervals (CIs) have frequently been proposed as a more

  6. Chaotic dynamics from interspike intervals

    DEFF Research Database (Denmark)

    Pavlov, A N; Sosnovtseva, Olga; Mosekilde, Erik

    2001-01-01

    Considering two different mathematical models describing chaotic spiking phenomena, namely, an integrate-and-fire and a threshold-crossing model, we discuss the problem of extracting dynamics from interspike intervals (ISIs) and show that the possibilities of computing the largest Lyapunov expone...

  7. Interval matrices: Regularity generates singularity

    Czech Academy of Sciences Publication Activity Database

    Rohn, Jiří; Shary, S.P.

    2018-01-01

    Roč. 540, 1 March (2018), s. 149-159 ISSN 0024-3795 Institutional support: RVO:67985807 Keywords : interval matrix * regularity * singularity * P-matrix * absolute value equation * diagonally singilarizable matrix Subject RIV: BA - General Mathematics Impact factor: 0.973, year: 2016

  8. Haemostatic reference intervals in pregnancy

    DEFF Research Database (Denmark)

    Szecsi, Pal Bela; Jørgensen, Maja; Klajnbard, Anna

    2010-01-01

    Haemostatic reference intervals are generally based on samples from non-pregnant women. Thus, they may not be relevant to pregnant women, a problem that may hinder accurate diagnosis and treatment of haemostatic disorders during pregnancy. In this study, we establish gestational age-specific refe......Haemostatic reference intervals are generally based on samples from non-pregnant women. Thus, they may not be relevant to pregnant women, a problem that may hinder accurate diagnosis and treatment of haemostatic disorders during pregnancy. In this study, we establish gestational age......-specific reference intervals for coagulation tests during normal pregnancy. Eight hundred one women with expected normal pregnancies were included in the study. Of these women, 391 had no complications during pregnancy, vaginal delivery, or postpartum period. Plasma samples were obtained at gestational weeks 13......-20, 21-28, 29-34, 35-42, at active labor, and on postpartum days 1 and 2. Reference intervals for each gestational period using only the uncomplicated pregnancies were calculated in all 391 women for activated partial thromboplastin time (aPTT), fibrinogen, fibrin D-dimer, antithrombin, free protein S...

  9. Dynamic Properties of QT Intervals

    Czech Academy of Sciences Publication Activity Database

    Halámek, Josef; Jurák, Pavel; Vondra, Vlastimil; Lipoldová, J.; Leinveber, Pavel; Plachý, M.; Fráňa, P.; Kára, T.

    2009-01-01

    Roč. 36, - (2009), s. 517-520 ISSN 0276-6574 R&D Projects: GA ČR GA102/08/1129; GA MŠk ME09050 Institutional research plan: CEZ:AV0Z20650511 Keywords : QT Intervals * arrhythmia diagnosis Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering http://cinc.mit.edu/archives/2009/pdf/0517.pdf

  10. Calibration interval technical basis document

    International Nuclear Information System (INIS)

    Chiaro, P.J. Jr.

    1998-09-01

    This document provides a method for the establishment and evaluation of calibration intervals for radiation protection instrumentation. This document is applicable to instrumentation used by personnel at US Department of Energy (DOE) facilities for the measurement of radioactive contamination and the measurement and monitoring of radiation fields for protection of personnel and the environment. Special calibrations are not addressed by this document and should be handled separately

  11. Haemostatic reference intervals in pregnancy.

    Science.gov (United States)

    Szecsi, Pal B; Jørgensen, Maja; Klajnbard, Anna; Andersen, Malene R; Colov, Nina P; Stender, Steen

    2010-04-01

    Haemostatic reference intervals are generally based on samples from non-pregnant women. Thus, they may not be relevant to pregnant women, a problem that may hinder accurate diagnosis and treatment of haemostatic disorders during pregnancy. In this study, we establish gestational age-specific reference intervals for coagulation tests during normal pregnancy. Eight hundred one women with expected normal pregnancies were included in the study. Of these women, 391 had no complications during pregnancy, vaginal delivery, or postpartum period. Plasma samples were obtained at gestational weeks 13-20, 21-28, 29-34, 35-42, at active labor, and on postpartum days 1 and 2. Reference intervals for each gestational period using only the uncomplicated pregnancies were calculated in all 391 women for activated partial thromboplastin time (aPTT), fibrinogen, fibrin D-dimer, antithrombin, free protein S, and protein C and in a subgroup of 186 women in addition for prothrombin time (PT), Owren and Quick PT, protein S activity, and total protein S and coagulation factors II, V, VII, VIII, IX, X, XI, and XII. The level of coagulation factors II, V, X, XI, XII and antithrombin, protein C, aPTT, PT remained largely unchanged during pregnancy, delivery, and postpartum and were within non-pregnant reference intervals. However, levels of fibrinogen, D-dimer, and coagulation factors VII, VIII, and IX increased markedly. Protein S activity decreased substantially, while free protein S decreased slightly and total protein S was stable. Gestational age-specific reference values are essential for the accurate interpretation of a subset of haemostatic tests during pregnancy, delivery, and puerperium.

  12. Evidence for increased glutamatergic cortical facilitation in children and adolescents with major depressive disorder.

    Science.gov (United States)

    Croarkin, Paul E; Nakonezny, Paul A; Husain, Mustafa M; Melton, Tabatha; Buyukdura, Jeylan S; Kennard, Betsy D; Emslie, Graham J; Kozel, F Andrew; Daskalakis, Zafiris J

    2013-03-01

    Converging lines of evidence implicate the glutamate and γ-aminobutyric acid neurotransmitter systems in the pathophysiology of major depressive disorder. Transcranial magnetic stimulation cortical excitability and inhibition paradigms have been used to assess cortical glutamatergic and γ-aminobutyric acid-mediated tone in adults with major depressive disorder, but not in children and adolescents. To compare measures of cortical excitability and inhibition with 4 different paradigms in a group of children and adolescents with major depressive disorder vs healthy controls. Cross-sectional study examining medication-free children and adolescents (aged 9-17 years) with major depressive disorder compared with healthy controls. Cortical excitability was assessed with motor threshold and intracortical facilitation measures. Cortical inhibition was measured with cortical silent period and intracortical inhibition paradigms. University-based child and adolescent psychiatry clinic and neurostimulation laboratory. Twenty-four participants with major depressive disorder and 22 healthy controls matched for age and sex. Patients with major depressive disorder were medication naive and had moderate to severe symptoms based on an evaluation with a child and adolescent psychiatrist and scores on the Children's Depression Rating Scale-Revised. Motor threshold, intracortical facilitation, cortical silent period, and intracortical inhibition. Compared with healthy controls, depressed patients had significantly increased intracortical facilitation at interstimulus intervals of 10 and 15 milliseconds bilaterally. There were no significant group differences in cortical inhibition measures. These findings suggest that major depressive disorder in children and adolescents is associated with increased intracortical facilitation and excessive glutamatergic activity.

  13. Statistical intervals a guide for practitioners

    CERN Document Server

    Hahn, Gerald J

    2011-01-01

    Presents a detailed exposition of statistical intervals and emphasizes applications in industry. The discussion differentiates at an elementary level among different kinds of statistical intervals and gives instruction with numerous examples and simple math on how to construct such intervals from sample data. This includes confidence intervals to contain a population percentile, confidence intervals on probability of meeting specified threshold value, and prediction intervals to include observation in a future sample. Also has an appendix containing computer subroutines for nonparametric stati

  14. Variational collocation on finite intervals

    International Nuclear Information System (INIS)

    Amore, Paolo; Cervantes, Mayra; Fernandez, Francisco M

    2007-01-01

    In this paper, we study a set of functions, defined on an interval of finite width, which are orthogonal and which reduce to the sinc functions when the appropriate limit is taken. We show that these functions can be used within a variational approach to obtain accurate results for a variety of problems. We have applied them to the interpolation of functions on finite domains and to the solution of the Schroedinger equation, and we have compared the performance of the present approach with others

  15. Chaotic dynamics from interspike intervals

    DEFF Research Database (Denmark)

    Pavlov, A N; Sosnovtseva, Olga; Mosekilde, Erik

    2001-01-01

    Considering two different mathematical models describing chaotic spiking phenomena, namely, an integrate-and-fire and a threshold-crossing model, we discuss the problem of extracting dynamics from interspike intervals (ISIs) and show that the possibilities of computing the largest Lyapunov exponent...... (LE) from point processes differ between the two models. We also consider the problem of estimating the second LE and the possibility to diagnose hyperchaotic behavior by processing spike trains. Since the second exponent is quite sensitive to the structure of the ISI series, we investigate...

  16. Chaotic dynamics from interspike intervals

    DEFF Research Database (Denmark)

    Pavlov, A.N.; Sosnovtseva, Olga V.; Mosekilde, Erik

    2001-01-01

    Considering two different mathematical models describing chaotic spiking phenomena, namely, an integrate-and-fire and a threshold-crossing model, we discuss the problem of extracting dynamics from interspike intervals (ISIs) and show that the possibilities of computing the largest Lyapunov exponent...... (LE) from paint processes differ between the two models. We also consider the problem of estimating the second LE and the possibility to diagnose hyperchaotic behavior by processing spike trains. Since the second exponent is quite sensitive to the structure of the ISI series, we investigate...

  17. Dijets at large rapidity intervals

    CERN Document Server

    Pope, B G

    2001-01-01

    Inclusive diet production at large pseudorapidity intervals ( Delta eta ) between the two jets has been suggested as a regime for observing BFKL dynamics. We have measured the dijet cross section for large Delta eta in pp collisions at square root s = 1800 and 630 GeV using the DOE detector. The partonic cross section increases strongly with the size of Delta eta . The observed growth is even stronger than expected on the basis of BFKL resummation in the leading logarithmic approximation. The growth of the partonic cross section can be accommodated with an effective BFKL intercept of alpha /sub BFKL/(20 GeV) = 1.65 +or- 0.07.

  18. Haemostatic reference intervals in pregnancy

    DEFF Research Database (Denmark)

    Szecsi, Pal Bela; Jørgensen, Maja; Klajnbard, Anna

    2010-01-01

    , and protein C and in a subgroup of 186 women in addition for prothrombin time (PT), Owren and Quick PT, protein S activity, and total protein S and coagulation factors II, V, VII, VIII, IX, X, XI, and XII. The level of coagulation factors II, V, X, XI, XII and antithrombin, protein C, aPTT, PT remained...... largely unchanged during pregnancy, delivery, and postpartum and were within non-pregnant reference intervals. However, levels of fibrinogen, D-dimer, and coagulation factors VII, VIII, and IX increased markedly. Protein S activity decreased substantially, while free protein S decreased slightly and total...

  19. Some Characterizations of Convex Interval Games

    NARCIS (Netherlands)

    Brânzei, R.; Tijs, S.H.; Alparslan-Gok, S.Z.

    2008-01-01

    This paper focuses on new characterizations of convex interval games using the notions of exactness and superadditivity. We also relate big boss interval games with concave interval games and obtain characterizations of big boss interval games in terms of exactness and subadditivity.

  20. Combination of interval set and soft set

    Directory of Open Access Journals (Sweden)

    Keyun Qin

    2013-04-01

    Full Text Available Soft set theory and interval set theory are all mathematical tools for dealing with uncertainties. This paper is devoted to the discussion of soft interval set and its application. The notion of soft interval sets is introduced by combining soft set and interval set. Several operations on soft interval sets are presented in a manner parallel to that used in defining operations on soft sets and the lattice structures of soft interval sets are established. In addition, a soft interval set based decision making problem is analyzed.

  1. Modulation of sensory inhibition of motor evoked potentials elicited by TMS prior to movement?

    DEFF Research Database (Denmark)

    Leukel, Christian; Lundbye-Jensen, Jesper; Nielsen, Jens Bo

    Short latency afferent inhibition (SAI) refers to a decrement of the size of a motor evoked potential (MEP) by transcranial magnetic stimulation (TMS) after electrical stimulation of a peripheral afferent nerve (PNS) (Tokimura et al. 2000). Since SAI occurs when TMS is applied at the time...... of the arrival of the peripheral afferent volley at the sensorimotor cortex, it likely reflects sensory activation of inhibitory intracortical circuits (Alle et al. 2009). In the present study, we aimed to investigate modulation of this inhibitory effect prior to movement (flexion of the index finger) compared...... of corticospinal cells to TMS, which starts approximately 100 ms prior to the onset of movement (Chen et al. 1998). Thus, it is hypothesized that the modulation of the MEP prior to movement is linked to the afferent volley arriving at the sensorimotor cortex. It might be speculated that the MEP was facilitated...

  2. Using the confidence interval confidently.

    Science.gov (United States)

    Hazra, Avijit

    2017-10-01

    Biomedical research is seldom done with entire populations but rather with samples drawn from a population. Although we work with samples, our goal is to describe and draw inferences regarding the underlying population. It is possible to use a sample statistic and estimates of error in the sample to get a fair idea of the population parameter, not as a single value, but as a range of values. This range is the confidence interval (CI) which is estimated on the basis of a desired confidence level. Calculation of the CI of a sample statistic takes the general form: CI = Point estimate ± Margin of error, where the margin of error is given by the product of a critical value (z) derived from the standard normal curve and the standard error of point estimate. Calculation of the standard error varies depending on whether the sample statistic of interest is a mean, proportion, odds ratio (OR), and so on. The factors affecting the width of the CI include the desired confidence level, the sample size and the variability in the sample. Although the 95% CI is most often used in biomedical research, a CI can be calculated for any level of confidence. A 99% CI will be wider than 95% CI for the same sample. Conflict between clinical importance and statistical significance is an important issue in biomedical research. Clinical importance is best inferred by looking at the effect size, that is how much is the actual change or difference. However, statistical significance in terms of P only suggests whether there is any difference in probability terms. Use of the CI supplements the P value by providing an estimate of actual clinical effect. Of late, clinical trials are being designed specifically as superiority, non-inferiority or equivalence studies. The conclusions from these alternative trial designs are based on CI values rather than the P value from intergroup comparison.

  3. Pigeons' Choices between Fixed-Interval and Random-Interval Schedules: Utility of Variability?

    Science.gov (United States)

    Andrzejewski, Matthew E.; Cardinal, Claudia D.; Field, Douglas P.; Flannery, Barbara A.; Johnson, Michael; Bailey, Kathleen; Hineline, Philip N.

    2005-01-01

    Pigeons' choosing between fixed-interval and random-interval schedules of reinforcement was investigated in three experiments using a discrete-trial procedure. In all three experiments, the random-interval schedule was generated by sampling a probability distribution at an interval (and in multiples of the interval) equal to that of the…

  4. A note on birth interval distributions

    International Nuclear Information System (INIS)

    Shrestha, G.

    1989-08-01

    A considerable amount of work has been done regarding the birth interval analysis in mathematical demography. This paper is prepared with the intention of reviewing some probability models related to interlive birth intervals proposed by different researchers. (author). 14 refs

  5. An Adequate First Order Logic of Intervals

    DEFF Research Database (Denmark)

    Chaochen, Zhou; Hansen, Michael Reichhardt

    1998-01-01

    This paper introduces left and right neighbourhoods as primitive interval modalities to define other unary and binary modalities of intervals in a first order logic with interval length. A complete first order logic for the neighbourhood modalities is presented. It is demonstrated how the logic can...... support formal specification and verification of liveness and fairness, and also of various notions of real analysis....

  6. Skew products of interval maps over subshifts

    NARCIS (Netherlands)

    Gharaei, Masoumeh; Homburg, Ale Jan

    2016-01-01

    We treat step skew products over transitive subshifts of finite type with interval fibers. The fiber maps are diffeomorphisms on the interval; we assume that the end points of the interval are fixed under the fiber maps. Our paper thus extends work by V. Kleptsyn and D. Volk who treated step skew

  7. Consistency and Refinement for Interval Markov Chains

    DEFF Research Database (Denmark)

    Delahaye, Benoit; Larsen, Kim Guldstrand; Legay, Axel

    2012-01-01

    Interval Markov Chains (IMC), or Markov Chains with probability intervals in the transition matrix, are the base of a classic specification theory for probabilistic systems [18]. The standard semantics of IMCs assigns to a specification the set of all Markov Chains that satisfy its interval...

  8. Electrocardiographic PR Interval Duration and Cardiovascular Risk

    DEFF Research Database (Denmark)

    Rasmussen, Peter Vibe; Nielsen, Jonas Bille; Skov, Morten Wagner

    2017-01-01

    Background Because of ambiguous reports in the literature, we aimed to investigate the association between PR interval and the risk of all-cause and cardiovascular death, heart failure, and pacemaker implantation, allowing for a nonlinear relationship. MethodsWe included 293,111 individuals...... into 7 groups based on the population PR interval distribution. Cox models were used, with reference to a PR interval between 152 and 161 ms (40th to ..., and 1805 pacemaker implantations. A short PR interval ( PR interval ( > 200 ms; HR, 1.23; 95% CI, 1.14-1.32; P

  9. Probability Distribution for Flowing Interval Spacing

    International Nuclear Information System (INIS)

    Kuzio, S.

    2001-01-01

    The purpose of this analysis is to develop a probability distribution for flowing interval spacing. A flowing interval is defined as a fractured zone that transmits flow in the Saturated Zone (SZ), as identified through borehole flow meter surveys (Figure 1). This analysis uses the term ''flowing interval spacing'' as opposed to fractured spacing, which is typically used in the literature. The term fracture spacing was not used in this analysis because the data used identify a zone (or a flowing interval) that contains fluid-conducting fractures but does not distinguish how many or which fractures comprise the flowing interval. The flowing interval spacing is measured between the midpoints of each flowing interval. Fracture spacing within the SZ is defined as the spacing between fractures, with no regard to which fractures are carrying flow. The Development Plan associated with this analysis is entitled, ''Probability Distribution for Flowing Interval Spacing'', (CRWMS M and O 2000a). The parameter from this analysis may be used in the TSPA SR/LA Saturated Zone Flow and Transport Work Direction and Planning Documents: (1) ''Abstraction of Matrix Diffusion for SZ Flow and Transport Analyses'' (CRWMS M and O 1999a) and (2) ''Incorporation of Heterogeneity in SZ Flow and Transport Analyses'', (CRWMS M and O 1999b). A limitation of this analysis is that the probability distribution of flowing interval spacing may underestimate the effect of incorporating matrix diffusion processes in the SZ transport model because of the possible overestimation of the flowing interval spacing. Larger flowing interval spacing results in a decrease in the matrix diffusion processes. This analysis may overestimate the flowing interval spacing because the number of fractures that contribute to a flowing interval cannot be determined from the data. Because each flowing interval probably has more than one fracture contributing to a flowing interval, the true flowing interval spacing could be

  10. Motor pathway excitability in ATP13A2 mutation carriers

    DEFF Research Database (Denmark)

    Zittel, S; Kroeger, J; van der Vegt, J P M

    2012-01-01

    OBJECTIVE: To describe excitability of motor pathways in Kufor-Rakeb syndrome (PARK9), an autosomal recessive nigro-striatal-pallidal-pyramidal neurodegeneration caused by a mutation in the ATP13A2 gene, using transcranial magnetic stimulation (TMS). METHODS: Five members of a Chilean family...... with an ATP13A2 mutation (one affected mutation carrier (MC) with a compound heterozygous mutation, 4 asymptomatic MC with a single heterozygous mutation) and 11 healthy subjects without mutations were studied. We measured motor evoked potentials (MEP), the contralateral silent period (cSP), short interval...... intracortical inhibition (SICI), intracortical facilitation (ICF), short latency afferent inhibition (SAI) as markers of intracortical intrahemispheric inhibition/facilitation and the ipsilateral silent period (iSP) and paired-pulse interhemispheric inhibition (IHI) to probe interhemispheric motor interactions...

  11. Transcranial alternating current stimulation at beta frequency: lack of immediate effects on excitation and interhemispheric inhibition of the human motor cortex

    Directory of Open Access Journals (Sweden)

    Viola Rjosk

    2016-11-01

    Full Text Available Transcranial alternating current stimulation (tACS is a form of noninvasive brain stimulation and is capable of influencing brain oscillations and cortical networks. In humans, the endogenous oscillation frequency in sensorimotor areas peaks at 20 Hz. This beta-band typically occurs during maintenance of tonic motor output and seems to play a role in interhemispheric coordination of movements. Previous studies showed that tACS applied in specific frequency bands over primary motor cortex (M1 or the visual cortex modulates cortical excitability within the stimulated hemisphere. However, the particular impact remains controversial because effects of tACS were shown to be frequency, duration and location specific. Furthermore, the potential of tACS to modulate cortical interhemispheric processing, like interhemispheric inhibition (IHI, remains elusive. Transcranial magnetic stimulation (TMS is a noninvasive and well-tolerated method of directly activating neurons in superficial areas of the human brain and thereby a useful tool for evaluating the functional state of motor pathways. The aim of the present study was to elucidate the immediate effect of 10 min tACS in the β-frequency band (20 Hz over left M1 on IHI between M1s in 19 young, healthy, right-handed participants. A series of TMS measurements (MEP size, RMT, IHI from left to right M1 and vice versa was performed before and immediately after tACS or sham using a double-blinded, cross-over design. We did not find any significant tACS-induced modulations of intracortical excitation (as assessed by MEP size and RMT and/or interhemispheric inhibition (IHI. These results indicate that 10 min of 20 Hz tACS over left M1 seems incapable of modulating immediate brain activity or inhibition. Further studies are needed to elucidate potential aftereffects of 20 Hz tACS as well as frequency-specific effects of tACS on intracortical excitation and interhemispheric inhibition.

  12. Interval Forecast for Smooth Transition Autoregressive Model ...

    African Journals Online (AJOL)

    In this paper, we propose a simple method for constructing interval forecast for smooth transition autoregressive (STAR) model. This interval forecast is based on bootstrapping the residual error of the estimated STAR model for each forecast horizon and computing various Akaike information criterion (AIC) function. This new ...

  13. Confidence Interval Approximation For Treatment Variance In ...

    African Journals Online (AJOL)

    In a random effects model with a single factor, variation is partitioned into two as residual error variance and treatment variance. While a confidence interval can be imposed on the residual error variance, it is not possible to construct an exact confidence interval for the treatment variance. This is because the treatment ...

  14. New interval forecast for stationary autoregressive models ...

    African Journals Online (AJOL)

    In this paper, we proposed a new forecasting interval for stationary Autoregressive, AR(p) models using the Akaike information criterion (AIC) function. Ordinarily, the AIC function is used to determine the order of an AR(p) process. In this study however, AIC forecast interval compared favorably with the theoretical forecast ...

  15. Interpretation of Confidence Interval Facing the Conflict

    Science.gov (United States)

    Andrade, Luisa; Fernández, Felipe

    2016-01-01

    As literature has reported, it is usual that university students in statistics courses, and even statistics teachers, interpret the confidence level associated with a confidence interval as the probability that the parameter value will be between the lower and upper interval limits. To confront this misconception, class activities have been…

  16. Nonparametric confidence intervals for monotone functions

    NARCIS (Netherlands)

    Groeneboom, P.; Jongbloed, G.

    2015-01-01

    We study nonparametric isotonic confidence intervals for monotone functions. In [Ann. Statist. 29 (2001) 1699–1731], pointwise confidence intervals, based on likelihood ratio tests using the restricted and unrestricted MLE in the current status model, are introduced. We extend the method to the

  17. INTERVAL OBSERVER FOR A BIOLOGICAL REACTOR MODEL

    Directory of Open Access Journals (Sweden)

    T. A. Kharkovskaia

    2014-05-01

    Full Text Available The method of an interval observer design for nonlinear systems with parametric uncertainties is considered. The interval observer synthesis problem for systems with varying parameters consists in the following. If there is the uncertainty restraint for the state values of the system, limiting the initial conditions of the system and the set of admissible values for the vector of unknown parameters and inputs, the interval existence condition for the estimations of the system state variables, containing the actual state at a given time, needs to be held valid over the whole considered time segment as well. Conditions of the interval observers design for the considered class of systems are shown. They are: limitation of the input and state, the existence of a majorizing function defining the uncertainty vector for the system, Lipschitz continuity or finiteness of this function, the existence of an observer gain with the suitable Lyapunov matrix. The main condition for design of such a device is cooperativity of the interval estimation error dynamics. An individual observer gain matrix selection problem is considered. In order to ensure the property of cooperativity for interval estimation error dynamics, a static transformation of coordinates is proposed. The proposed algorithm is demonstrated by computer modeling of the biological reactor. Possible applications of these interval estimation systems are the spheres of robust control, where the presence of various types of uncertainties in the system dynamics is assumed, biotechnology and environmental systems and processes, mechatronics and robotics, etc.

  18. Physiology and its Importance for Reference Intervals

    Science.gov (United States)

    Sikaris, Kenneth A

    2014-01-01

    Reference intervals are ideally defined on apparently healthy individuals and should be distinguished from clinical decision limits that are derived from known diseased patients. Knowledge of physiological changes is a prerequisite for understanding and developing reference intervals. Reference intervals may differ for various subpopulations because of differences in their physiology, most obviously between men and women, but also in childhood, pregnancy and the elderly. Changes in laboratory measurements may be due to various physiological factors starting at birth including weaning, the active toddler, immunological learning, puberty, pregnancy, menopause and ageing. The need to partition reference intervals is required when there are significant physiological changes that need to be recognised. It is important that laboratorians are aware of these changes otherwise reference intervals that attempt to cover a widened inter-individual variability may lose their usefulness. It is virtually impossible for any laboratory to directly develop reference intervals for each of the physiological changes that are currently known, however indirect techniques can be used to develop or validate reference intervals in some difficult situations such as those for children. Physiology describes our life’s journey, and it is only when we are familiar with that journey that we can appreciate a pathological departure. PMID:24659833

  19. Fast transfer of crossmodal time interval training.

    Science.gov (United States)

    Chen, Lihan; Zhou, Xiaolin

    2014-06-01

    Sub-second time perception is essential for many important sensory and perceptual tasks including speech perception, motion perception, motor coordination, and crossmodal interaction. This study investigates to what extent the ability to discriminate sub-second time intervals acquired in one sensory modality can be transferred to another modality. To this end, we used perceptual classification of visual Ternus display (Ternus in Psychol Forsch 7:81-136, 1926) to implicitly measure participants' interval perception in pre- and posttests and implemented an intra- or crossmodal sub-second interval discrimination training protocol in between the tests. The Ternus display elicited either an "element motion" or a "group motion" percept, depending on the inter-stimulus interval between the two visual frames. The training protocol required participants to explicitly compare the interval length between a pair of visual, auditory, or tactile stimuli with a standard interval or to implicitly perceive the length of visual, auditory, or tactile intervals by completing a non-temporal task (discrimination of auditory pitch or tactile intensity). Results showed that after fast explicit training of interval discrimination (about 15 min), participants improved their ability to categorize the visual apparent motion in Ternus displays, although the training benefits were mild for visual timing training. However, the benefits were absent for implicit interval training protocols. This finding suggests that the timing ability in one modality can be rapidly acquired and used to improve timing-related performance in another modality and that there may exist a central clock for sub-second temporal processing, although modality-specific perceptual properties may constrain the functioning of this clock.

  20. Generalized production planning problem under interval uncertainty

    Directory of Open Access Journals (Sweden)

    Samir A. Abass

    2010-06-01

    Full Text Available Data in many real life engineering and economical problems suffer from inexactness. Herein we assume that we are given some intervals in which the data can simultaneously and independently perturb. We consider the generalized production planning problem with interval data. The interval data are in both of the objective function and constraints. The existing results concerning the qualitative and quantitative analysis of basic notions in parametric production planning problem. These notions are the set of feasible parameters, the solvability set and the stability set of the first kind.

  1. Dijet production at large rapidity intervals

    International Nuclear Information System (INIS)

    Del Duca, V.; Schmidt, C.R.

    1993-11-01

    We examine dijet production at large rapidity intervals at Tevatron energies, by using the theory of Lipatov and collaborators which resums the leading powers of the rapidity interval. We analyze the growth of the Mueller-navelet K-factor in this context and find it to be negligible. However, we do find a considerable enhancement of jet production at large transverse momenta. In addition, we show that the correlation in transverse momentum and azimuthal angle of the tagging jets fades away as the rapidity interval is increased. (orig.)

  2. Direct Interval Forecasting of Wind Power

    DEFF Research Database (Denmark)

    Wan, Can; Xu, Zhao; Pinson, Pierre

    2013-01-01

    This letter proposes a novel approach to directly formulate the prediction intervals of wind power generation based on extreme learning machine and particle swarm optimization, where prediction intervals are generated through direct optimization of both the coverage probability and sharpness, wit......, without the prior knowledge of forecasting errors. The proposed approach has been proved to be highly efficient and reliable through preliminary case studies using real-world wind farm data, indicating a high potential of practical application.......This letter proposes a novel approach to directly formulate the prediction intervals of wind power generation based on extreme learning machine and particle swarm optimization, where prediction intervals are generated through direct optimization of both the coverage probability and sharpness...

  3. Surveillance intervals for small abdominal aortic aneurysms

    DEFF Research Database (Denmark)

    Bown, Matthew J; Sweeting, Michael J; Brown, Louise C

    2013-01-01

    Small abdominal aortic aneurysms (AAAs [3.0 cm-5.4 cm in diameter]) are monitored by ultrasound surveillance. The intervals between surveillance scans should be chosen to detect an expanding aneurysm prior to rupture.......Small abdominal aortic aneurysms (AAAs [3.0 cm-5.4 cm in diameter]) are monitored by ultrasound surveillance. The intervals between surveillance scans should be chosen to detect an expanding aneurysm prior to rupture....

  4. Optimal prediction intervals of wind power generation

    DEFF Research Database (Denmark)

    Wan, Can; Wu, Zhao; Pinson, Pierre

    2014-01-01

    direct optimization of both the coverage probability and sharpness to ensure the quality. The proposed method does not involve the statistical inference or distribution assumption of forecasting errors needed in most existing methods. Case studies using real wind farm data from Australia have been...... penetration beforehand. This paper proposes a novel hybrid intelligent algorithm approach to directly formulate optimal prediction intervals of wind power generation based on extreme learning machine and particle swarm optimization. Prediction intervals with Associated confidence levels are generated through...

  5. Establishing reference intervals in the coagulation laboratory.

    Science.gov (United States)

    Castellone, D D

    2017-05-01

    Obtaining a reference interval (RI) is a challenge for any laboratory and becomes more complicated in the coagulation laboratory due to testing on samples with limited stability on reagents that are poorly standardized. Reference intervals are required to be able to evaluate results in relation to a patients' hemostatic disorder. This becomes one of the most important tasks conducted in the coagulation laboratory. However, many laboratories lack the time, finances and in many cases the expertise to conduct this study. Many RI are obtained from package inserts, or from publications written by experts in lieu of laboratories conducting their own studies. An overview of validating reference intervals and options for verifying or transference of reference intervals is discussed. Based on the confidence interval and the acceptability of risk laboratories are willing to accept, coagulation laboratories have options to conduct robust studies for their RI. Data mining or global reference studies may help to provide data for age specific ranges. Pre-analytical variables and selection of healthy subjects have the largest impact on coagulation testing outcomes and need to be well controlled during the establishment of reference intervals. Laboratories have options in lieu of conducting a full validation on how to verify RI based on smaller RI studies or transference of RI after determining compatibility of the original RI study. © 2017 John Wiley & Sons Ltd.

  6. Interval Size and Affect: An Ethnomusicological Perspective

    Directory of Open Access Journals (Sweden)

    Sarha Moore

    2013-08-01

    Full Text Available This commentary addresses Huron and Davis's question of whether "The Harmonic Minor Provides an Optimum Way of Reducing Average Melodic Interval Size, Consistent with Sad Affect Cues" within any non-Western musical cultures. The harmonic minor scale and other semitone-heavy scales, such as Bhairav raga and Hicaz makam, are featured widely in the musical cultures of North India and the Middle East. Do melodies from these genres also have a preponderance of semitone intervals and low incidence of the augmented second interval, as in Huron and Davis's sample? Does the presence of more semitone intervals in a melody affect its emotional connotations in different cultural settings? Are all semitone intervals equal in their effect? My own ethnographic research within these cultures reveals comparable connotations in melodies that linger on semitone intervals, centered on concepts of tension and metaphors of falling. However, across different musical cultures there may also be neutral or lively interpretations of these same pitch sets, dependent on context, manner of performance, and tradition. Small pitch movement may also be associated with social functions such as prayer or lullabies, and may not be described as "sad." "Sad," moreover may not connote the same affect cross-culturally.

  7. Recurrence interval analysis of trading volumes.

    Science.gov (United States)

    Ren, Fei; Zhou, Wei-Xing

    2010-06-01

    We study the statistical properties of the recurrence intervals τ between successive trading volumes exceeding a certain threshold q. The recurrence interval analysis is carried out for the 20 liquid Chinese stocks covering a period from January 2000 to May 2009, and two Chinese indices from January 2003 to April 2009. Similar to the recurrence interval distribution of the price returns, the tail of the recurrence interval distribution of the trading volumes follows a power-law scaling, and the results are verified by the goodness-of-fit tests using the Kolmogorov-Smirnov (KS) statistic, the weighted KS statistic and the Cramér-von Mises criterion. The measurements of the conditional probability distribution and the detrended fluctuation function show that both short-term and long-term memory effects exist in the recurrence intervals between trading volumes. We further study the relationship between trading volumes and price returns based on the recurrence interval analysis method. It is found that large trading volumes are more likely to occur following large price returns, and the comovement between trading volumes and price returns is more pronounced for large trading volumes.

  8. Probability Distribution for Flowing Interval Spacing

    International Nuclear Information System (INIS)

    S. Kuzio

    2004-01-01

    Fracture spacing is a key hydrologic parameter in analyses of matrix diffusion. Although the individual fractures that transmit flow in the saturated zone (SZ) cannot be identified directly, it is possible to determine the fractured zones that transmit flow from flow meter survey observations. The fractured zones that transmit flow as identified through borehole flow meter surveys have been defined in this report as flowing intervals. The flowing interval spacing is measured between the midpoints of each flowing interval. The determination of flowing interval spacing is important because the flowing interval spacing parameter is a key hydrologic parameter in SZ transport modeling, which impacts the extent of matrix diffusion in the SZ volcanic matrix. The output of this report is input to the ''Saturated Zone Flow and Transport Model Abstraction'' (BSC 2004 [DIRS 170042]). Specifically, the analysis of data and development of a data distribution reported herein is used to develop the uncertainty distribution for the flowing interval spacing parameter for the SZ transport abstraction model. Figure 1-1 shows the relationship of this report to other model reports that also pertain to flow and transport in the SZ. Figure 1-1 also shows the flow of key information among the SZ reports. It should be noted that Figure 1-1 does not contain a complete representation of the data and parameter inputs and outputs of all SZ reports, nor does it show inputs external to this suite of SZ reports. Use of the developed flowing interval spacing probability distribution is subject to the limitations of the assumptions discussed in Sections 5 and 6 of this analysis report. The number of fractures in a flowing interval is not known. Therefore, the flowing intervals are assumed to be composed of one flowing zone in the transport simulations. This analysis may overestimate the flowing interval spacing because the number of fractures that contribute to a flowing interval cannot be

  9. High frequency somatosensory stimulation increases sensori-motor inhibition and leads to perceptual improvement in healthy subjects.

    Science.gov (United States)

    Rocchi, Lorenzo; Erro, Roberto; Antelmi, Elena; Berardelli, Alfredo; Tinazzi, Michele; Liguori, Rocco; Bhatia, Kailash; Rothwell, John

    2017-06-01

    High frequency repetitive somatosensory stimulation (HF-RSS), which is a patterned electric stimulation applied to the skin through surface electrodes, improves two-point discrimination, somatosensory temporal discrimination threshold (STDT) and motor performance in humans. However, the mechanisms which underlie these changes are still unknown. In particular, we hypothesize that refinement of inhibition might be responsible for the improvement in spatial and temporal perception. Fifteen healthy subjects underwent 45min of HF-RSS. Before and after the intervention several measures of inhibition in the primary somatosensory area (S1), such as paired-pulse somatosensory evoked potentials (pp-SEP), high-frequency oscillations (HFO), and STDT were tested, as well as tactile spatial acuity and short intracortical inhibition (SICI). HF-RSS increased inhibition in S1 tested by pp-SEP and HFO; these changes were correlated with improvement in STDT. HF-RSS also enhanced bumps detection, while there was no change in grating orientation test. Finally there was an increase in SICI, suggesting widespread changes in cortical sensorimotor interactions. These findings suggest that HF-RSS can improve spatial and temporal tactile abilities by increasing the effectiveness of inhibitory interactions in the somatosensory system. Moreover, HF-RSS induces changes in cortical sensorimotor interaction. HF-RSS is a repetitive electric stimulation technique able to modify the effectiveness of inhibitory circuitry in the somatosensory system and primary motor cortex. Copyright © 2017 International Federation of Clinical Neurophysiology. All rights reserved.

  10. Reorganization of the primary motor cortex following lower-limb amputation for vascular disease: a pre-post-amputation comparison.

    Science.gov (United States)

    Hordacre, Brenton; Bradnam, Lynley V; Crotty, Maria

    2017-08-01

    This study compared bilateral corticomotor and intracortical excitability of the primary motor cortex (M1), pre- and post-unilateral transtibial amputation. Three males aged 45, 55, and 48 years respectively who were scheduled for elective amputation and thirteen (10 male, 3 female) healthy control participants aged 58.9 (SD 9.8) were recruited. Transcranial magnetic stimulation assessed corticomotor and intracortical excitability of M1 bilaterally. Neurophysiological assessments were performed 10 (SD 7) days prior to surgery and again at 10 (SD 3) days following surgery. Data were analyzed descriptively and objectively compared to 95% confidence intervals from control data. Prior to amputation, all three patients demonstrated stronger short-latency intracortical inhibition evoked from M1 ipsilateral to the affected limb and reduced long-latency intracortical inhibition evoked from M1 contralateral to the affected limb compared to control subjects. Following amputation, short-latency intracortical inhibition was reduced in both M1s and long-latency intracortical inhibition was reduced for the ipsilateral M1. Single-pulse motor evoked potential amplitude and motor thresholds were similar pre-to-post amputation. Modulation of intracortical excitability shortly following amputation indicates that the cortical environment may be optimized for reorganization in the acute post-amputation period which might be significant for learning to support prosthetic mobility. Implications for Rehabilitation Amputation of a lower-limb is associated with extensive reorganization at the level of the cortex. Reorganization occurs in the acute post-amputation period implying a favorable cortical environment for recovery. Rehabilitation or brain interventions may target the acute pre-prosthetic post-amputation period to optimize recovery.

  11. Computed assisted detection of interval breast cancers

    International Nuclear Information System (INIS)

    Moberg, Kerstin; Bjurstam, Nils; Wilczek, Brigitte; Rostgaard, Lars; Egge, Elisabeth; Muren, Catharina

    2001-01-01

    Objectives: To examine interval cancer detection rate for a system of computer assisted detection (CAD) and its influence on radiologists' sensitivity/specificity in a screen-like retrospective review situation. Materials and methods: Three screening radiologists reviewed previous screen images of 59 interval cancers mixed with other screening mammograms (ratio 1:5) and non-mixed. Mixed interval cases were interpreted both without and with aid of CAD. Results: CAD detected a number of 14 interval cancers while the three radiologists detected 17, 12 and 11 without and 16, 10 and 13 with CAD. Although CAD specificity was low (38%) no reduction in radiologists' specificity occurred using CAD (73%, 82% and 89% without and 78%, 90% and 92% with CAD). Non-mixed reading increased radiologists' detection rate to 21, 17 and 19 interval cancers respectively. Conclusion: Despite sufficiently high sensitivity for CAD alone no increase in radiologist sensitivity (or decrease in specificity) occurred with CAD. Improving CAD specificity, with unaffectedly high sensitivity, should make radiologists more inclined to revise interpretations according to CAD. The potential sensitivity increase, noted when using CAD as a double reader, could be realised in this way

  12. Return Intervals Approach to Financial Fluctuations

    Science.gov (United States)

    Wang, Fengzhong; Yamasaki, Kazuko; Havlin, Shlomo; Stanley, H. Eugene

    Financial fluctuations play a key role for financial markets studies. A new approach focusing on properties of return intervals can help to get better understanding of the fluctuations. A return interval is defined as the time between two successive volatilities above a given threshold. We review recent studies and analyze the 1000 most traded stocks in the US stock markets. We find that the distribution of the return intervals has a well approximated scaling over a wide range of thresholds. The scaling is also valid for various time windows from one minute up to one trading day. Moreover, these results are universal for stocks of different countries, commodities, interest rates as well as currencies. Further analysis shows some systematic deviations from a scaling law, which are due to the nonlinear correlations in the volatility sequence. We also examine the memory in return intervals for different time scales, which are related to the long-term correlations in the volatility. Furthermore, we test two popular models, FIGARCH and fractional Brownian motion (fBm). Both models can catch the memory effect but only fBm shows a good scaling in the return interval distribution.

  13. The Case for Common Reference Intervals

    Science.gov (United States)

    Jones, Graham RD; Barker, Antony; Tate, Jill; Lim, Chen-Fee; Robertson, Ken

    2004-01-01

    The current paradigm for pathology reference intervals is for each laboratory to determine its own interval for use with each test offered by the laboratory. It is our contention that this approach does not best serve the medical community, especially at a time when electronic databases of health information are being expanded and integrated. We also believe that this approach is not performed well in many laboratories and is excessively expensive in practice. In contrast, we believe that the preferable option is to develop and apply common reference intervals throughout Australia and New Zealand, together with common reporting formats and assay standardisation wherever this is possible. We are aware that these are neither trivial nor simple issues, however we believe that failure to achieve this goal where technically possible will be a failure of the pathology profession to meet the challenges of the modern health community. PMID:18458709

  14. Existence test for asynchronous interval iterations

    DEFF Research Database (Denmark)

    Madsen, Kaj; Caprani, O.; Stauning, Ole

    1997-01-01

    In the search for regions that contain fixed points ofa real function of several variables, tests based on interval calculationscan be used to establish existence ornon-existence of fixed points in regions that are examined in the course ofthe search. The search can e.g. be performed...... as a synchronous (sequential) interval iteration:In each iteration step all components of the iterate are calculatedbased on the previous iterate. In this case it is straight forward to base simple interval existence and non-existencetests on the calculations done in each step of the iteration. The search can also...... on thecomponentwise calculations done in the course of the iteration. These componentwisetests are useful for parallel implementation of the search, sincethe tests can then be performed local to each processor and only when a test issuccessful do a processor communicate this result to other processors....

  15. Aging and motor inhibition: a converging perspective provided by brain stimulation and imaging approaches.

    Science.gov (United States)

    Levin, Oron; Fujiyama, Hakuei; Boisgontier, Matthieu P; Swinnen, Stephan P; Summers, Jeffery J

    2014-06-01

    The ability to inhibit actions, one of the hallmarks of human motor control, appears to decline with advancing age. Evidence for a link between changes in inhibitory functions and poor motor performance in healthy older adults has recently become available with transcranial magnetic stimulation (TMS). Overall, these studies indicate that the capacity to modulate intracortical (ICI) and interhemispheric (IHI) inhibition is preserved in high-performing older individuals. In contrast, older individuals exhibiting motor slowing and a declined ability to coordinate movement appear to show a reduced capability to modulate GABA-mediated inhibitory processes. As a decline in the integrity of the GABA-ergic inhibitory processes may emerge due to age-related loss of white and gray matter, a promising direction for future research would be to correlate individual differences in structural and/or functional integrity of principal brain networks with observed changes in inhibitory processes within cortico-cortical, interhemispheric, and/or corticospinal pathways. Finally, we underscore the possible links between reduced inhibitory functions and age-related changes in brain activation patterns. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Interval logic. Proof theory and theorem proving

    DEFF Research Database (Denmark)

    Rasmussen, Thomas Marthedal

    2002-01-01

    of a direction of an interval, and present a sound and complete Hilbert proof system for it. Because of its generality, SIL can conveniently act as a general formalism in which other interval logics can be encoded. We develop proof theory for SIL including both a sequent calculus system and a labelled natural...... deduction system. We conduct theoretical investigations of the systems with respect to subformula properties, proof search, etc. The generic theorem proving system Isabelle is used as a framework for encoding both proof theoretical systems. We consider a number of examples/small case-studies and discuss...

  17. POSTMORTAL CHANGES AND ASSESSMENT OF POSTMORTEM INTERVAL

    Directory of Open Access Journals (Sweden)

    Edin Šatrović

    2013-01-01

    Full Text Available This paper describes in a simple way the changes that occur in the body after death.They develop in a specific order, and the speed of their development and their expression are strongly influenced by various endogenous and exogenous factors. The aim of the authors is to indicate the characteristics of the postmortem changes, and their significance in establishing time since death, which can be established precisely within 72 hours. Accurate evaluation of the age of the corpse based on the common changes is not possible with longer postmortem intervals, so the entomological findings become the most significant change on the corpse for determination of the postmortem interval (PMI.

  18. Conditional prediction intervals of wind power generation

    DEFF Research Database (Denmark)

    Pinson, Pierre; Kariniotakis, Georges

    2010-01-01

    A generic method for the providing of prediction intervals of wind power generation is described. Prediction intervals complement the more common wind power point forecasts, by giving a range of potential outcomes for a given probability, their so-called nominal coverage rate. Ideally they inform...... of the situation-specific uncertainty of point forecasts. In order to avoid a restrictive assumption on the shape of forecast error distributions, focus is given to an empirical and nonparametric approach named adapted resampling. This approach employs a fuzzy inference model that permits to integrate expertise...

  19. Risk based surveillance test interval optimization

    International Nuclear Information System (INIS)

    Cepin, M.; Mavko, B.

    1995-01-01

    First step towards the risk based regulation is to determine the optimal surveillance test intervals for the safety equipment which is tested at nuclear power plant operation. In the paper we have presented the process of optimal surveillance test interval optimization from our perspective. It consist of three levels: component level, system level and plant level. It bases on the results of the Probabilistic Safety Assessment and is focused to minimize risk. At component and system level the risk measure is component or system mean unavailability respectively. At plant level the risk measure is core damage frequency. (author)

  20. Is an interval the right result of arithmetic operations on intervals?

    OpenAIRE

    Piegat Andrzej; Landowski Marek

    2017-01-01

    For many scientists interval arithmetic (IA, I arithmetic) seems to be easy and simple. However, this is not true. Interval arithmetic is complicated. This is confirmed by the fact that, for years, new, alternative versions of this arithmetic have been created and published. These new versions tried to remove shortcomings and weaknesses of previously proposed options of the arithmetic, which decreased the prestige not only of interval arithmetic itself, but also of fuzzy arithmetic, which, to...

  1. Statistics of return intervals between long heartbeat intervals and their usability for online prediction of disorders

    International Nuclear Information System (INIS)

    Bogachev, Mikhail I; Bunde, Armin; Kireenkov, Igor S; Nifontov, Eugene M

    2009-01-01

    We study the statistics of return intervals between large heartbeat intervals (above a certain threshold Q) in 24 h records obtained from healthy subjects. We find that both the linear and the nonlinear long-term memory inherent in the heartbeat intervals lead to power-laws in the probability density function P Q (r) of the return intervals. As a consequence, the probability W Q (t; Δt) that at least one large heartbeat interval will occur within the next Δt heartbeat intervals, with an increasing elapsed number of intervals t after the last large heartbeat interval, follows a power-law. Based on these results, we suggest a method of obtaining a priori information about the occurrence of the next large heartbeat interval, and thus to predict it. We show explicitly that the proposed method, which exploits long-term memory, is superior to the conventional precursory pattern recognition technique, which focuses solely on short-term memory. We believe that our results can be straightforwardly extended to obtain more reliable predictions in other physiological signals like blood pressure, as well as in other complex records exhibiting multifractal behaviour, e.g. turbulent flow, precipitation, river flows and network traffic.

  2. Statistics of return intervals between long heartbeat intervals and their usability for online prediction of disorders

    Energy Technology Data Exchange (ETDEWEB)

    Bogachev, Mikhail I; Bunde, Armin [Institut fuer Theoretische Physik III, Justus-Liebig-Universitaet Giessen, Heinrich-Buff-Ring 16, 35392, Giessen (Germany); Kireenkov, Igor S; Nifontov, Eugene M [Faculty Therapy Department, Pavlov State Medical University, Lev Tolstoy Street 6/8, 197022, St Petersburg (Russian Federation)], E-mail: Mikhail.Bogachev@physik.uni-giessen.de

    2009-06-15

    We study the statistics of return intervals between large heartbeat intervals (above a certain threshold Q) in 24 h records obtained from healthy subjects. We find that both the linear and the nonlinear long-term memory inherent in the heartbeat intervals lead to power-laws in the probability density function P{sub Q}(r) of the return intervals. As a consequence, the probability W{sub Q}(t; {delta}t) that at least one large heartbeat interval will occur within the next {delta}t heartbeat intervals, with an increasing elapsed number of intervals t after the last large heartbeat interval, follows a power-law. Based on these results, we suggest a method of obtaining a priori information about the occurrence of the next large heartbeat interval, and thus to predict it. We show explicitly that the proposed method, which exploits long-term memory, is superior to the conventional precursory pattern recognition technique, which focuses solely on short-term memory. We believe that our results can be straightforwardly extended to obtain more reliable predictions in other physiological signals like blood pressure, as well as in other complex records exhibiting multifractal behaviour, e.g. turbulent flow, precipitation, river flows and network traffic.

  3. Trial order and retention interval in human predictive judgment.

    Science.gov (United States)

    Stout, Steven C; Amundson, Jeffrey C; Miller, Ralph R

    2005-12-01

    The influences of order of trial type and retention interval on human predictive judgments were assessed for a cue that was reinforced on half of its training presentations. Subjects observed 10 cue-outcome presentations (i.e., reinforced trials) and 10 cue-alone presentations (i.e., nonreinforced trials) in one of three different orders: all nonreinforced trials followed by all reinforced trials(latent inhibition), reinforced and nonreinforced trials interspersed (partial reinforcement), or al lreinforced trials followed by all nonreinforced trials (extinction). Ratings were based mainly on the most recent event type (i.e., a recency effect) when the test occurred immediately after training but were based mainly on initial event types (i.e., a primacy effect) when the test occurred after a 48-h delay. The subjects tested both immediately and with a long retention interval did not exhibit this shift to primacy (i.e., the recency effect persisted). These results demonstrate noncatastrophic forgetting and the flexible use of trial order information in predictive judgments.

  4. Precise Interval Timer for Software Defined Radio

    Science.gov (United States)

    Pozhidaev, Aleksey (Inventor)

    2014-01-01

    A precise digital fractional interval timer for software defined radios which vary their waveform on a packet-by-packet basis. The timer allows for variable length in the preamble of the RF packet and allows to adjust boundaries of the TDMA (Time Division Multiple Access) Slots of the receiver of an SDR based on the reception of the RF packet of interest.

  5. Coefficient Omega Bootstrap Confidence Intervals: Nonnormal Distributions

    Science.gov (United States)

    Padilla, Miguel A.; Divers, Jasmin

    2013-01-01

    The performance of the normal theory bootstrap (NTB), the percentile bootstrap (PB), and the bias-corrected and accelerated (BCa) bootstrap confidence intervals (CIs) for coefficient omega was assessed through a Monte Carlo simulation under conditions not previously investigated. Of particular interests were nonnormal Likert-type and binary items.…

  6. Population based reference intervals for common blood ...

    African Journals Online (AJOL)

    Population based reference intervals for common blood haematological and biochemical parameters in the Akuapem north district. K.A Koram, M.M Addae, J.C Ocran, S Adu-amankwah, W.O Rogers, F.K Nkrumah ...

  7. Diagnostic interval and mortality in colorectal cancer

    DEFF Research Database (Denmark)

    Tørring, Marie Louise; Frydenberg, Morten; Hamilton, William

    2012-01-01

    Objective To test the theory of a U-shaped association between time from the first presentation of symptoms in primary care to the diagnosis (the diagnostic interval) and mortality after diagnosis of colorectal cancer (CRC). Study Design and Setting Three population-based studies in Denmark...

  8. Quinsy tonsillectomy or interval tonsillectomy - a prospective ...

    African Journals Online (AJOL)

    Fifty-one patients with peritonsillar abscesses were randomised to undergo either quinsy tonsillectomy (aT) or interval tonsillectomy (IT), and the two groups were compared. The QT group lost fewer (10,3 v. 17,9) working days and less blood during the operation (158,6 ml v. 205,7 ml); haemostasis was easier and the ...

  9. Linear chord diagrams on two intervals

    DEFF Research Database (Denmark)

    Andersen, Jørgen Ellegaard; Penner, Robert; Reidys, Christian

    generating function ${\\bf C}_g(z)=z^{2g}R_g(z)/(1-4z)^{3g-{1\\over 2}}$ for chords attached to a single interval is algebraic, for $g\\geq 1$, where the polynomial $R_g(z)$ with degree at most $g-1$ has integer coefficients and satisfies $R_g(1/4)\

  10. Coefficient Alpha Bootstrap Confidence Interval under Nonnormality

    Science.gov (United States)

    Padilla, Miguel A.; Divers, Jasmin; Newton, Matthew

    2012-01-01

    Three different bootstrap methods for estimating confidence intervals (CIs) for coefficient alpha were investigated. In addition, the bootstrap methods were compared with the most promising coefficient alpha CI estimation methods reported in the literature. The CI methods were assessed through a Monte Carlo simulation utilizing conditions…

  11. Interval scanning photomicrography of microbial cell populations.

    Science.gov (United States)

    Casida, L. E., Jr.

    1972-01-01

    A single reproducible area of the preparation in a fixed focal plane is photographically scanned at intervals during incubation. The procedure can be used for evaluating the aerobic or anaerobic growth of many microbial cells simultaneously within a population. In addition, the microscope is not restricted to the viewing of any one microculture preparation, since the slide cultures are incubated separately from the microscope.

  12. A sequent calculus for signed interval logic

    DEFF Research Database (Denmark)

    Rasmussen, Thomas Marthedal

    2001-01-01

    We propose and discuss a complete sequent calculus formulation for Signed Interval Logic (SIL) with the chief purpose of improving proof support for SIL in practice. The main theoretical result is a simple characterization of the limit between decidability and undecidability of quantifier-free SIL...

  13. Modal Transition Systems with Weight Intervals

    DEFF Research Database (Denmark)

    Juhl, Line; Larsen, Kim Guldstrand; Srba, Jiri

    2012-01-01

    We propose weighted modal transition systems, an extension to the well-studied specification formalism of modal transition systems that allows to express both required and optional behaviours of their intended implementations. In our extension we decorate each transition with a weight interval...

  14. Equidistant Intervals in Perspective Photographs and Paintings

    Science.gov (United States)

    2016-01-01

    Human vision is extremely sensitive to equidistance of spatial intervals in the frontal plane. Thresholds for spatial equidistance have been extensively measured in bisecting tasks. Despite the vast number of studies, the informational basis for equidistance perception is unknown. There are three possible sources of information for spatial equidistance in pictures, namely, distances in the picture plane, in physical space, and visual space. For each source, equidistant intervals were computed for perspective photographs of walls and canals. Intervals appear equidistant if equidistance is defined in visual space. Equidistance was further investigated in paintings of perspective scenes. In appraisals of the perspective skill of painters, emphasis has been on accurate use of vanishing points. The current study investigated the skill of painters to depict equidistant intervals. Depicted rows of equidistant columns, tiles, tapestries, or trees were analyzed in 30 paintings and engravings. Computational analysis shows that from the middle ages until now, artists either represented equidistance in physical space or in a visual space of very limited depth. Among the painters and engravers who depict equidistance in a highly nonveridical visual space are renowned experts of linear perspective. PMID:27698983

  15. Interval Appendicectomy and Management of Appendix Mass ...

    African Journals Online (AJOL)

    A wholly conservative management without interval appendicectomy was instituted for 13 patients diagnosed as having appendix mass between 1998 and 2002 in the University of Benin Teaching Hospital, Benin City, Nigeria. Within three days of admission, one patient developed clinical features of ruptured appendix and ...

  16. Safety information on QT-interval prolongation

    DEFF Research Database (Denmark)

    Warnier, Miriam J; Holtkamp, Frank A; Rutten, Frans H

    2014-01-01

    Prolongation of the QT interval can predispose to fatal ventricular arrhythmias. Differences in QT-labeling language can result in miscommunication and suboptimal risk mitigation. We systematically compared the phraseology used to communicate on QT-prolonging properties of 144 drugs newly approve...

  17. Retention interval and intertrial interval in a serial learning or delayed discrimination task.

    Science.gov (United States)

    Capaldi, E J; Miller, D J; Nawrocki, T M

    1986-01-01

    In each of four experiments, rats were provided with the same three-event decreasing series (18-1-0) of 0.045-g food pellets in a runway. Tracking, running fast to 18 pellets and running slow to 1 and 0 pellets, was investigated as a function of the temporal interval elapsing between the events of the series (the retention interval), shifts in retention interval, and number of trials each day (or the intertrial interval), a trial being defined as presentation of each of the three events of the series. Neither retention interval, which varied from 15 s to 30 min in various investigations, nor shifts in retention interval affected tracking when only one trial was given each day. But when more than one daily trial was given, tracking was acquired more slowly and was disrupted by a shift in retention interval from 15 s to 5 min. Tracking was also disrupted by a shift from one to two trials each day. These results indicate that when given one 18-1-0 trial each day, the rat partitions events on a first-event/subsequent-event basis; that little forgetting occurs even at long retention intervals; that somewhat different memories signal events when one or more than one 18-1-0 trial occurs each day; and that retention interval deficits can arise owing to the same or similar memories' signaling different events. The results described limit the generality of three hypotheses suggested in two recent investigations: that as retention interval increases, rats find it increasingly difficult to remember and utilize serial position cues; that tracking in serial tasks is not influenced by number of trials each day; and that there are specific stimuli associated with each retention interval which, when changed, necessarily disrupt performance.

  18. Haematological reference intervals in a multiethnic population.

    Directory of Open Access Journals (Sweden)

    Angeli Ambayya

    Full Text Available Similar to other populations, full blood count reference (FBC intervals in Malaysia are generally derived from non-Malaysian subjects. However, numerous studies have shown significant differences between and within populations supporting the need for population specific intervals.Two thousand seven hundred twenty five apparently healthy adults comprising all ages, both genders and three principal races were recruited through voluntary participation. FBC was performed on two analysers, Sysmex XE-5000 and Unicel DxH 800, in addition to blood smears and haemoglobin analysis. Serum ferritin, soluble transferrin receptor and C-reactive protein assays were performed in selected subjects. All parameters of qualified subjects were tested for normality followed by determination of reference intervals, measures of central tendency and dispersion along with point estimates for each subgroup.Complete data was available in 2440 subjects of whom 56% (907 women and 469 men were included in reference interval calculation. Compared to other populations there were significant differences for haemoglobin, red blood cell count, platelet count and haematocrit in Malaysians. There were differences between men and women, and between younger and older men; unlike in other populations, haemoglobin was similar in younger and older women. However ethnicity and smoking had little impact. 70% of anemia in premenopausal women, 24% in postmenopausal women and 20% of males is attributable to iron deficiency. There was excellent correlation between Sysmex XE-5000 and Unicel DxH 800.Our data confirms the importance of population specific haematological parameters and supports the need for local guidelines rather than adoption of generalised reference intervals and cut-offs.

  19. Selecting clinically relevant populations for reference intervals.

    Science.gov (United States)

    Ritchie, Robert F; Palomaki, Glenn

    2004-01-01

    The selection of individuals to represent a group for any purpose can commit the effort to success or failure from the very outset. The description of this group must reflect what is, in reality, the purpose for which the group is being studied. Considering that reference intervals are designed to assist clinicians during diagnostic triage, criteria must reflect the nature of the subjects entering the system for care. The majority of people seeking care have non-life-threatening, yet troublesome complaints. In other words, persons who are in a reasonable state of health and who are not suffering from significant illness. Therefore the relevant cohort should fit this description, not individuals who lack any clinical or laboratory issues. Our focus is to employ reference intervals to exclude disease and not to define normality. Normality in the eyes of statisticians is quite different from the word as viewed by clinical staff, yet the term is used interchangeably without concern for its ultimate use. As a result medicine today stumbles over this issue at every turn. Scientists and artists do not speak the same language. Compounding this awkward situation has been the conviction that by increasing laboratory precision and accuracy, the utility of laboratory data, reference intervals in particular, will improve clinical understanding. This has, after many years, not proven to be the case. What has become very evident, however, is that unsustainably large sums of money are being devoted to improving laboratory performance. To what end, when we are unable to grasp the significance of what is available now including published reference intervals for common test values? A realistic perspective on the value of prevailing laboratory performance, as illustrated by reference intervals, must be adopted. The obligation of laboratories, its regulators and professional groups is to create a sustainable mechanism to provide clinically usable information, in a timely and affordable

  20. INHIBITION IN SPEAKING PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Isna Humaera

    2015-09-01

    Full Text Available The most common problem encountered by the learner in the language acquisition process is learner inhibition. Inhibition refers to a temperamental tendency to display wariness, fearfulness, or restrain in response to unfamiliar people, objects, and situations. There are some factors that cause inhibition, such as lack of motivation, shyness, self-confidence, self-esteem, and language ego. There are also levels of inhibition, it refers to kinds of inhibition and caused of inhibition itself. Teacher can support their students to reduce their inhibition effect by many ways, one of them by creating good classroom management including establishing good rapport between teacher and learners.

  1. Is an interval the right result of arithmetic operations on intervals?

    Directory of Open Access Journals (Sweden)

    Piegat Andrzej

    2017-09-01

    Full Text Available For many scientists interval arithmetic (IA, I arithmetic seems to be easy and simple. However, this is not true. Interval arithmetic is complicated. This is confirmed by the fact that, for years, new, alternative versions of this arithmetic have been created and published. These new versions tried to remove shortcomings and weaknesses of previously proposed options of the arithmetic, which decreased the prestige not only of interval arithmetic itself, but also of fuzzy arithmetic, which, to a great extent, is based on it. In our opinion, the main reason for the observed shortcomings of the present IA is the assumption that the direct result of arithmetic operations on intervals is also an interval. However, the interval is not a direct result but only a simplified representative (indicator of the result. This hypothesis seems surprising, but investigations prove that it is true. The paper shows what conditions should be satisfied by the result of interval arithmetic operations to call it a “result”, how great its dimensionality is, how to perform arithmetic operations and solve equations. Examples illustrate the proposed method of interval computations.

  2. Cognitive inhibition of number/length interference in a Piaget-like task: evidence by combining ERP and MEG.

    Science.gov (United States)

    Joliot, Marc; Leroux, Gaëlle; Dubal, Stéphanie; Tzourio-Mazoyer, Nathalie; Houdé, Olivier; Mazoyer, Bernard; Petit, Laurent

    2009-08-01

    We combined event-related potential (ERP) and magnetoencephalography (MEG) acquisition and analysis to investigate the electrophysiological markers of the inhibitory processes involved in the number/length interference in a Piaget-like numerical task. Eleven healthy subjects performed four gradually interfering conditions with the heuristic "length equals number" to be inhibited. Low resolution tomography reconstruction was performed on the combined grand averaged electromagnetic data at the early (N1, P1) and late (P2, N2, P3(early) and P3(late)) latencies. Every condition was analyzed at both scalp and regional brain levels. The inhibitory processes were visible on the late components of the electromagnetic brain activity. A right P2-related frontal orbital activation reflected the change of strategy in the inhibitory processes. N2-related SMA/cingulate activation revealed the first occurrence of the stimuli processing to be inhibited. Both P3 components revealed the working memory processes operating in a medial temporal complex and the mental imagery processes subtended by the precuneus. Simultaneous ERP and MEG signal acquisition and analysis allowed to describe the spatiotemporal patterns of neural networks involved in the inhibition of the "length equals number" interference. Combining ERP and MEG ensured a sensitivity which could be reached previously only through invasive intracortical recordings.

  3. Circadian profile of QT interval and QT interval variability in 172 healthy volunteers

    DEFF Research Database (Denmark)

    Bonnemeier, Hendrik; Wiegand, Uwe K H; Braasch, Wiebke

    2003-01-01

    The limited prognostic value of QT dispersion has been demonstrated in recent studies. However, longitudinal data on physiological variations of QT interval and the influence of aging and sex are few. This analysis included 172 healthy subjects (89 women, 83 men; mean age 38.7 +/- 15 years). Beat......-to-beat QT interval duration (QT, QTapex [QTa], Tend [Te]), variability (QTSD, QTaSD), and the mean R-R interval were determined from 24-hour ambulatory electrocardiograms after exclusion of artifacts and premature beats. All volunteers were fully active, awoke at approximately 7:00 AM, and had 6-8 hours...... lower at day- and nighttime. Aging was associated with an increase of QT interval mainly at daytime and a significant shift of the T wave apex towards the end of the T wave. The circadian profile of ventricular repolarization is strongly related to the mean R-R interval, however, there are significant...

  4. Time-Interval Measurement of Stuttering: Modifying Interjudge Agreement.

    Science.gov (United States)

    Ingham, Roger J.; And Others

    1993-01-01

    Two experiments investigating interval-by-interval interjudge and intrajudge agreement for stuttered and nonstuttered speech intervals found that training of judges could improve reliability levels; judges with relatively high intrajudge agreement also showed relatively higher interjudge agreement; and interval-by-interval interjudge agreement was…

  5. Interval Mathematics Applied to Critical Point Transitions

    Directory of Open Access Journals (Sweden)

    Benito A. Stradi

    2012-03-01

    Full Text Available The determination of critical points of mixtures is important for both practical and theoretical reasons in the modeling of phase behavior, especially at high pressure. The equations that describe the behavior of complex mixtures near critical points are highly nonlinear and with multiplicity of solutions to the critical point equations. Interval arithmetic can be used to reliably locate all the critical points of a given mixture. The method also verifies the nonexistence of a critical point if a mixture of a given composition does not have one. This study uses an interval Newton/Generalized Bisection algorithm that provides a mathematical and computational guarantee that all mixture critical points are located. The technique is illustrated using several example problems. These problems involve cubic equation of state models; however, the technique is general purpose and can be applied in connection with other nonlinear problems.

  6. Appendix mass: conservative management without interval appendectomy.

    Science.gov (United States)

    Hoffmann, J; Lindhard, A; Jensen, H E

    1984-09-01

    Forty-nine patients had conservative treatment of an appendix mass without interval appendectomy. Five were lost to follow-up within 6 months, and 44 patients were followed for between 6 months and 22 years. In nine patients (20 percent) recurrent appendicitis developed, and six (14 percent) suffered chronic pain not thought to be due to appendicitis. Of the recurrences, 66 percent occurred within 2 years of the initial attack. Barium examination of the cecum was successful in diagnosing two of three additional patients in whom a right iliac fossa mass was not due to appendicitis. The morbidity and expense of routine interval appendectomy was thus eliminated in 80 percent of the patients.

  7. Systolic Time Intervals and New Measurement Methods.

    Science.gov (United States)

    Tavakolian, Kouhyar

    2016-06-01

    Systolic time intervals have been used to detect and quantify the directional changes of left ventricular function. New methods of recording these cardiac timings, which are less cumbersome, have been recently developed and this has created a renewed interest and novel applications for these cardiac timings. This manuscript reviews these new methods and addresses the potential for the application of these cardiac timings for the diagnosis and prognosis of different cardiac diseases.

  8. Quinsy tonsillectomy or interval tonsillectomy - a prospective ...

    African Journals Online (AJOL)

    Fifty-one patients with peritonsillar abscesses were randomised to undergo either quinsy tonsillectomy (aT) or interval tonsillectomy (IT), and the two groups were compared. The aT group lost fewer (10,3 v. 17,9) working days and less blood during the operation (158,6 ml v. 205,7 ml); haemostasis was easier and the ...

  9. Understanding Confidence Intervals With Visual Representations

    OpenAIRE

    Navruz, Bilgin; Delen, Erhan

    2014-01-01

    In the present paper, we showed how confidence intervals (CIs) are valuable and useful in research studies when they are used in the correct form with correct interpretations. The sixth edition of the APA (2010) Publication Manual strongly recommended reporting CIs in research studies, and it was described as “the best reporting strategy” (p. 34). Misconceptions and correct interpretations of CIs were presented from several textbooks. In addition, limitations of the null hypothesis statistica...

  10. Prolonged QT interval in Rett syndrome

    OpenAIRE

    Ellaway, C; Sholler, G; Leonard, H; Christodoulou, J

    1999-01-01

    Rett syndrome is a severe neurodevelopmental disorder of unknown aetiology. A prolonged QT interval has been described previously in patients with Rett syndrome. To investigate QT prolongation and the presence of cardiac tachyarrhythmias in Rett syndrome electrocardiography and 24 hour Holter monitoring were performed prospectively in a cohort of 34 girls with Rett syndrome. The corrected QT value was prolonged in nine patients. Compared with a group of healthy controls of a...

  11. Interval type–2 fuzzy decision making

    OpenAIRE

    Runkler, Thomas; Coupland, Simon; John, Robert

    2017-01-01

    Full text on Nottingham eprints - http://eprints.nottingham.ac.uk/36609/ This paper concerns itself with decision making under uncertainty and the consideration of risk. Type-1 fuzzy logic by its (essentially) crisp nature is limited in modelling decision making as there is no uncertainty in the membership function. We are interested in the role that interval type-2 fuzzy sets might play in enhancing decision making. Previous work by Bellman and Zadeh considered decision making to be based...

  12. INTERVALS OPTIMIZATION OF SYSTEMS INFORMATION SECURITY INSPECTION

    Directory of Open Access Journals (Sweden)

    V. A. Bogatyrev

    2014-09-01

    Full Text Available A Markov model is suggested for secure information systems, functioning under conditions of destructive impacts, which aftereffects are found by on-line and test control. It is assumed that on-line control, in contrast to the test one, is char- acterized by the limited control completeness, but does not require the stopping of computational process. The aim of re- search is to create models that optimize intervals of test control initialization by the criterion of probability maximization for system stay in the ready state to secure fulfillment of the functional requests and minimization of the dangerous system states in view of the uncertainty and intensity variance of the destructive impacts. Variants of testing intervals optimization are con- sidered depending on the intensity of destructive impacts by the criterion of the maximum system availability for the safe execution of queries. Optimization is carried out with and without adaptation to the actual intensity change of destructive impacts. The efficiency of adaptive change for testing periods is shown depending on the observed activity of destructive impacts. The solution of optimization problem is obtained by built-in tools of computer mathematics Mathcad 15, including symbolic mathematics for solution of systems of algebraic equations. The proposed models and methods of determining the optimal testing intervals can find their application in the system design of computer systems and networks of critical applications, working under conditions of destabilizing actions with the increased requirements for their safety.

  13. Early diastolic time intervals during hypertensive pregnancy.

    Science.gov (United States)

    Spinelli, L; Ferro, G; Nappi, C; Farace, M J; Talarico, G; Cinquegrana, G; Condorelli, M

    1987-10-01

    Early diastolic time intervals have been assessed by means of the echopolycardiographic method in 17 pregnant women who developed hypertension during pregnancy (HP) and in 14 normal pregnant women (N). Systolic time intervals (STI), stroke volume (SV), ejection fraction (EF), and mean velocity of myocardial fiber shortening (VCF) were also evaluated. Recordings were performed in the left lateral decubitus (LLD) and then in the supine decubitus (SD). In LLD, isovolumic relaxation period (IRP) was prolonged in the hypertensive pregnant women compared with normal pregnant women (HP 51 +/- 12.5 ms, N 32.4 +/- 15 ms p less than 0.05), whereas time of the mitral valve maximum opening (DE) was not different in the groups. There was no difference in SV, EF, and mean VCF, whereas STI showed only a significant (p less than 0.05) lengthening of pre-ejection period (PEP) in HP. When the subjects shifted from the left lateral to the supine decubitus position, left ventricular ejection time index (LVETi) and SV decreased significantly (p less than 0.05) in both normotensive hypertensive pregnant women. IRP and PEP lengthened significantly (p less than 0.05) only in normals, whereas they were unchanged in HP. DE time did not vary in either group. In conclusion, hypertension superimposed on pregnancy induces lengthening of IRP, as well as of PEP, and minimizes the effects of the postural changes in preload on the above-mentioned time intervals.

  14. Simplified interval type-2 fuzzy neural networks.

    Science.gov (United States)

    Lin, Yang-Yin; Liao, Shih-Hui; Chang, Jyh-Yeong; Lin, Chin-Teng

    2014-05-01

    This paper describes a self-evolving interval type-2 fuzzy neural network (FNN) for various applications. As type-1 fuzzy systems cannot effectively handle uncertainties in information within the knowledge base, we propose a simple interval type-2 FNN, which uses interval type-2 fuzzy sets in the premise and the Takagi-Sugeno-Kang (TSK) type in the consequent of the fuzzy rule. The TSK-type consequent of fuzzy rule is a linear combination of exogenous input variables. Given an initially empty the rule-base, all rules are generated with on-line type-2 fuzzy clustering. Instead of the time-consuming K-M iterative procedure, the design factors ql and qr are learned to adaptively adjust the upper and lower positions on the left and right limit outputs, using the parameter update rule based on a gradient descent algorithm. Simulation results demonstrate that our approach yields fewer test errors and less computational complexity than other type-2 FNNs.

  15. Reciprocal inhibition in Parkinson's disease.

    Science.gov (United States)

    Tsai, C H; Chen, R S; Lu, C S

    1997-01-01

    We studied the inhibition of median H-reflex by conditioning stimuli on the radial nerve in 14 normal controls, 6 patients with unilateral and 1 patient with predominantly left-sided Parkinson's disease. In normal controls, the electrophysiological studies were performed on their right hands, yet both hands were examined in patient group. In the controls, we identified three inhibitory phases, with maximal inhibition at conditioning-test intervals of 0 ms (41.66 +/- 4.73%), 20 ms (45.19 +/- 4.33%), and 100 ms (44.55 +/- 6.84%), respectively. In the less- or a- symptomatic side of the patient group, the inhibitory patterns are similar to those of the controls. However, in the symptomatic arms, loss of inhibition, or even mild potentiation, was observed in the third inhibitory phase. When the symptomatic and asymptomatic sides of patients were compared, in contrast to the striking phenomenon found between symptomatic side and the controls, no difference was observed in the third phase. The current results imply that, although no obvious rigidity can be detected on the asymptomatic sides, subtle functional corruption may have occurred within the contralateral basal ganglia in patients with unilateral Parkinson's disease. The remarkable change of the third phase on the symptomatic sides of patients suggests the perturbation of the polysynaptic long latency reflex pathway may somehow play a role in the rigidity pathogenesis.

  16. Approximation of the semi-infinite interval

    Directory of Open Access Journals (Sweden)

    A. McD. Mercer

    1980-01-01

    Full Text Available The approximation of a function f∈C[a,b] by Bernstein polynomials is well-known. It is based on the binomial distribution. O. Szasz has shown that there are analogous approximations on the interval [0,∞ based on the Poisson distribution. Recently R. Mohapatra has generalized Szasz' result to the case in which the approximating function is αe−ux∑k=N∞(uxkα+β−1Γ(kα+βf(kαuThe present note shows that these results are special cases of a Tauberian theorem for certain infinite series having positive coefficients.

  17. Optimal ABC inventory classification using interval programming

    Science.gov (United States)

    Rezaei, Jafar; Salimi, Negin

    2015-08-01

    Inventory classification is one of the most important activities in inventory management, whereby inventories are classified into three or more classes. Several inventory classifications have been proposed in the literature, almost all of which have two main shortcomings in common. That is, the previous methods mainly rely on an expert opinion to derive the importance of the classification criteria which results in subjective classification, and they need precise item parameters before implementing the classification. While the problem has been predominantly considered as a multi-criteria, we examine the problem from a different perspective, proposing a novel optimisation model for ABC inventory classification in the form of an interval programming problem. The proposed interval programming model has two important features compared to the existing methods: it provides optimal results instead of an expert-based classification and it does not require precise values of item parameters, which are not almost always available before classification. Finally, by illustrating the proposed classification model in the form of numerical example, conclusion and suggestions for future works are presented.

  18. una experiencia de intervención

    Directory of Open Access Journals (Sweden)

    Cecilia Villarreal Montoya

    2007-01-01

    Full Text Available El artículo resume la experiencia de intervención con una familia de la escuela de Villa Esperanza de Pavas. Se trata de un matrimonio con dificultades para disciplinar a sus tres hijos varones de ocho, seis, y cuatro años. En primer lugar, se exponen los principios teóricos y metodológicos, para luego mostrar la aplicación de ellos en el proceso vivido por la familia. Se aplica el modelo de intervención estructural, que busca que la misma familia logre realizar, paso a paso, los cambios requeridos en la dinámica y estructura familiar. En la situación específica de esta familia, se observa el fortalecimiento de la pareja como tal y como madre y padre en la medida que van logrando asumir la autoridad en forma compartida para disciplinar a los hijos. Al compartir esta experiencia, la autora pretende estimular a profesionales en Orientación a asumir el reto de considerar a las familias de la comunidad estudiantil, de las instituciones educativas donde laboran, como parte importante en el quehacer orientador.

  19. Confidence intervals for directly standardized rates using mid-p gamma intervals.

    Science.gov (United States)

    Fay, Michael P; Kim, Sungwook

    2017-03-01

    Directly standardized rates continue to be an integral tool for presenting rates for diseases that are highly dependent on age, such as cancer. Statistically, these rates are modeled as a weighted sum of Poisson random variables. This is a difficult statistical problem, because there are k observed Poisson variables and k unknown means. The gamma confidence interval has been shown through simulations to have at least nominal coverage in all simulated scenarios, but it can be overly conservative. Previous modifications to that method have closer to nominal coverage on average, but they do not achieve the nominal coverage bound in all situations. Further, those modifications are not central intervals, and the upper coverage error rate can be substantially more than half the nominal error. Here we apply a mid-p modification to the gamma confidence interval. Typical mid-p methods forsake guaranteed coverage to get coverage that is sometimes higher and sometimes lower than the nominal coverage rate, depending on the values of the parameters. The mid-p gamma interval does not have guaranteed coverage in all situations; however, in the (not rare) situations where the gamma method is overly conservative, the mid-p gamma interval often has at least nominal coverage. The mid-p gamma interval is especially appropriate when one wants a central interval, since simulations show that in many situations both the upper and lower coverage error rates are on average less than or equal to half the nominal error rate. © Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

  20. The fallacy of placing confidence in confidence intervals

    NARCIS (Netherlands)

    Morey, Richard D.; Hoekstra, Rink; Rouder, Jeffrey N.; Lee, Michael D.; Wagenmakers, Eric-Jan

    2016-01-01

    Interval estimates – estimates of parameters that include an allowance for sampling uncertainty – have long been touted as a key component of statistical analyses. There are several kinds of interval estimates, but the most popular are confidence intervals (CIs): intervals that contain the true

  1. The fallacy of placing confidence in confidence intervals

    NARCIS (Netherlands)

    Morey, R.D.; Hoekstra, R.; Rouder, J.N.; Lee, M.D.; Wagenmakers, E.-J.

    Interval estimates – estimates of parameters that include an allowance for sampling uncertainty – have long been touted as a key component of statistical analyses. There are several kinds of interval estimates, but the most popular are confidence intervals (CIs): intervals that contain the true

  2. Interval-based reconstruction for uncertainty quantification in PET

    Science.gov (United States)

    Kucharczak, Florentin; Loquin, Kevin; Buvat, Irène; Strauss, Olivier; Mariano-Goulart, Denis

    2018-02-01

    A new directed interval-based tomographic reconstruction algorithm, called non-additive interval based expectation maximization (NIBEM) is presented. It uses non-additive modeling of the forward operator that provides intervals instead of single-valued projections. The detailed approach is an extension of the maximum likelihood—expectation maximization algorithm based on intervals. The main motivation for this extension is that the resulting intervals have appealing properties for estimating the statistical uncertainty associated with the reconstructed activity values. After reviewing previously published theoretical concepts related to interval-based projectors, this paper describes the NIBEM algorithm and gives examples that highlight the properties and advantages of this interval valued reconstruction.

  3. Confidence intervals for annual wind power production******

    Directory of Open Access Journals (Sweden)

    Bensoussan Alain

    2014-01-01

    Full Text Available Wind power is an intermittent resource due to wind speed intermittency. However wind speed can be described as a stochastic process with short memory. This allows us to derive a central limit theorem for the annual or pluri-annual wind power production and then get quantiles of the wind power production for one, ten or twenty years future periods. On the one hand, the interquantile spread offers a measurement of the intrinsic uncertainties of wind power production. On the other hand, different quantiles with different periods of time are used by financial institutions to quantify the financial risk of the wind turbine. Our method is then applied to real datasets corresponding to a French wind turbine. Since confidence intervals can be enhanced by taking into account seasonality, we present some tools for change point analysis on wind series.

  4. Supersymmetry and electroweak breaking in the interval

    International Nuclear Information System (INIS)

    Diego, David; Gersdorff, Gero von; Quiros, Mariano

    2005-01-01

    Hypermultiplets are considered in the five-dimensional interval where all fields are continuous and the boundary conditions are dynamically obtained from the action principle. The orbifold boundary conditions are obtained as particular cases. We can interpret the Scherk-Schwarz supersymmetry breaking as a misalignment of boundary conditions while a new source of supersymmetry breaking corresponding to a mismatch of different boundary parameters is identified. The latter can be viewed as coming from boundary supersymmetry breaking masses for hyperscalars and the nature of the corresponding supersymmetry breaking parameter is analyzed. For some regions of the parameter space where supersymmetry is broken (either by Scherk-Schwarz boundary conditions or by boundary hyperscalar masses) electroweak symmetry breaking can be triggered at the tree level

  5. Fusing photovoltaic data for improved confidence intervals

    Directory of Open Access Journals (Sweden)

    Ansgar Steland

    2017-01-01

    Full Text Available Characterizing and testing photovoltaic modules requires carefully made measurements on important variables such as the power output under standard conditions. When additional data is available, which has been collected using a different measurement system and therefore may be of different accuracy, the question arises how one can combine the information present in both data sets. In some cases one even has prior knowledge about the ordering of the variances of the measurement errors, which is not fully taken into account by commonly known estimators. We discuss several statistical estimators to combine the sample means of independent series of measurements, both under the assumption of heterogeneous variances and ordered variances. The critical issue is then to assess the estimator’s variance and to construct confidence intervals. We propose and discuss the application of a new jackknife variance estimator devised by [1] to such photovoltaic data, in order to assess the variability of common mean estimation under heterogeneous and ordered variances in a reliable and nonparametric way. When serial correlations are present, which usually a ect the marginal variances, it is proposed to construct a thinned data set by downsampling the series in such a way that autocorrelations are removed or dampened. We propose a data adaptive procedure which downsamples a series at irregularly spaced time points in such a way that the autocorrelations are minimized. The procedures are illustrated by applying them to real photovoltaic power output measurements from two different sun light flashers. In addition, focusing on simulations governed by real photovoltaic data, we investigate the accuracy of the jackknife approach and compare it with other approaches. Among those is a variance estimator based on Nair’s formula for Gaussian data and, as a parametric alternative, two Bayesian models. We investigate the statistical accuracy of the resulting confidence

  6. Selection-based Approach to Cooperative Interval Games

    OpenAIRE

    Bok, Jan; Hladík, Milan

    2014-01-01

    Cooperative interval games are a generalized model of cooperative games in which the worth of every coalition corresponds to a closed interval representing the possible outcomes of its cooperation. Selections are all possible outcomes of the interval game with no additional uncertainty. We introduce new selection-based classes of interval games and prove their characterization theorems and relations to existing classes based on the interval weakly better operator. We show new results regardin...

  7. Intractable properties of responding under a fixed-interval schedule

    OpenAIRE

    Gentry, G. David; Marr, M. Jackson

    1982-01-01

    The behavior engendered by the fixed-interval schedule is characterized by its variability within and across intervals. The present experiment was designed to assess further the magnitude of interval-to-interval dynamics and to explore conditions which might enhance control by response number for subsequent output. Pigeons were exposed to three experimental manipulations after responding had stabilized under a fixed-interval five-minute schedule. First, a discrete five-stimulus counter was ad...

  8. Reduced surround inhibition in musicians.

    Science.gov (United States)

    Shin, Hae-Won; Kang, Suk Y; Hallett, Mark; Sohn, Young H

    2012-06-01

    To investigate whether surround inhibition (SI) in the motor system is altered in professional musicians, we performed a transcranial magnetic stimulation (TMS) study in 10 professional musicians and 15 age-matched healthy non-musicians. TMS was set to be triggered by self-initiated flexion of the index finger at different intervals ranging from 3 to 1,000 ms. Average motor evoked potential (MEP) amplitudes obtained from self-triggered TMS were normalized to average MEPs of the control TMS at rest and expressed as a percentage. Normalized MEP amplitudes of the abductor digiti minimi (ADM) muscles were compared between the musicians and non-musicians with the primary analysis being the intervals between 3 and 80 ms (during the movement). A mixed-design ANOVA revealed a significant difference in normalized ADM MEPs during the index finger flexion between groups, with less SI in the musicians. This study demonstrated that the functional operation of SI is less strong in musicians than non-musicians, perhaps due to practice of movement synergies involving both muscles. Reduced SI, however, could lead susceptible musicians to be prone to develop task-specific dystonia.

  9. Intracortical cartography in an agranular area.

    Science.gov (United States)

    Shepherd, Gordon M G

    2009-01-01

    A well-defined granular layer 4 is a defining cytoarchitectonic feature associated with sensory areas of mammalian cerebral cortex, and one with hodological significance: the local axons ascending from cells in thalamorecipient layer 4 and connecting to layer 2/3 pyramidal neurons form a major feedforward excitatory interlaminar projection. Conversely, agranular cortical areas, lacking a distinct layer 4, pose a hodological conundrum: without a laminar basis for the canonical layer 4-->2/3 pathway, what is the basic circuit organization? This review highlights current challenges and prospects for local-circuit electroanatomy and electrophysiology in agranular cortex, focusing on the mouse. Different lines of evidence, drawn primarily from studies of motor areas in frontal cortex in rodents, support the view that synaptic circuits in agranular cortex are organized around prominent descending excitatory layer 2/3-->5 pathways targeting multiple classes of projection neurons.

  10. Restricted Interval Guelph permeameter: Theory and application

    International Nuclear Information System (INIS)

    Freifeld, Barry M.; Oldenburg, Curtis M.

    2003-01-01

    A constant head permeameter system has been developed for use in small diameter boreholes with any orientation. It is based upon the original Guelph permeameter concept of using a Mariotte siphon reservoir to control the applied head. The new tool, called a Restricted Interval Guelph (RIG) permeameter uses either a single pneumatic packer or straddle packer to restrict the area through which water is allowed to flow so that the borehole wetted area is independent of the applied head. The RIG permeameter has been used at Yucca Mountain, Nevada, in the nonwelded rhyolitic Paintbrush Tuff. Analysis of the acquired data is based upon saturated-unsaturated flow theory that relies upon the quasi-linear approximation to estimate field-saturated hydraulic conductivity (Kfs) and the a parameter (sorptive number) of the exponential relative hydraulic conductivity pressure head relationship. These results are compared with a numerical model based upon the solution of the Richards equation using a van Genuchten capillary pressure-saturation formulation. The numerical model incorporates laboratory capillary pressure versus saturation functions measured from cores taken from nearby boreholes. Comparison between the analytical and numerical approaches shows that the simple analytic model is valid for analyzing the data collected. Sensitivity analysis performed with the numerical model shows that the RIG permeameter is an effective tool for estimating permeability and sorptive number for the nonwelded Paintbrush Tuff

  11. Hematology reference intervals for neonatal Holstein calves.

    Science.gov (United States)

    Panousis, Nikolaos; Siachos, Nektarios; Kitkas, Georgios; Kalaitzakis, Emmanouil; Kritsepi-Konstantinou, Maria; Valergakis, Georgios E

    2018-01-09

    Data regarding hematologic reference intervals (RI) for neonatal calves have not been published yet. The aims of this study were: a) to establish hematology RIs for neonatal Holstein calves, b) to compare them with the RIs for lactating cows, and c) to investigate the relationship of age and gender with the hematologic profile of calves. Two-hundred and fifty-four clinically healthy Holstein calves (1-9days old, from 30 farms) and 82 healthy Holstein cows (between 30 and 150days in milk, from 10 farms) were blood sampled once for a complete blood count evaluation, using the ADVIA 120 hematology analyzer. An additional blood sample was collected from each calf for serum total protein concentration measurement. RIs and age-related RIs were calculated with the Reference Value Advisor freeware. Comparisons between calves and cows and between male and female calves were performed with t-test or Mann-Whitney test. Red blood cell count (RBC), white blood cell count (WBC), neutrophil, lymphocyte and platelet counts in calves were higher, while mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) were lower than in cows. Lymphocyte and platelets showed a notable increase through age. Finally, female calves had higher RBC, hematocrit and hemoglobin concentration than males. Age-specific RIs should be used for the interpretation of the complete blood count in Holstein calves. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. On randomized confidence intervals for the binomial probability

    OpenAIRE

    Kabaila, Paul

    2013-01-01

    Suppose that X_1,X_2,...,X_n are independent and identically Bernoulli(theta) distributed. Also suppose that our aim is to find an exact confidence interval for theta that is the intersection of a 1-\\alpha/2 upper confidence interval and a 1-\\alpha/2 lower confidence interval. The Clopper-Pearson interval is the standard such confidence interval for theta, which is widely used in practice. We consider the randomized confidence interval of Stevens, 1950 and present some extensions, including p...

  13. Confidence Intervals from Normalized Data: A correction to Cousineau (2005

    Directory of Open Access Journals (Sweden)

    Richard D. Morey

    2008-09-01

    Full Text Available Presenting confidence intervals around means is a common method of expressing uncertainty in data. Loftus and Masson (1994 describe confidence intervals for means in within-subjects designs. These confidence intervals are based on the ANOVA mean squared error. Cousineau (2005 presents an alternative to the Loftus and Masson method, but his method produces confidence intervals that are smaller than those of Loftus and Masson. I show why this is the case and offer a simple correction that makes the expected size of Cousineau confidence intervals the same as that of Loftus and Masson confidence intervals.

  14. High-intensity interval training: Modulating interval duration in overweight/obese men.

    Science.gov (United States)

    Smith-Ryan, Abbie E; Melvin, Malia N; Wingfield, Hailee L

    2015-05-01

    High-intensity interval training (HIIT) is a time-efficient strategy shown to induce various cardiovascular and metabolic adaptations. Little is known about the optimal tolerable combination of intensity and volume necessary for adaptations, especially in clinical populations. In a randomized controlled pilot design, we evaluated the effects of two types of interval training protocols, varying in intensity and interval duration, on clinical outcomes in overweight/obese men. Twenty-five men [body mass index (BMI) > 25 kg · m(2)] completed baseline body composition measures: fat mass (FM), lean mass (LM) and percent body fat (%BF) and fasting blood glucose, lipids and insulin (IN). A graded exercise cycling test was completed for peak oxygen consumption (VO2peak) and power output (PO). Participants were randomly assigned to high-intensity short interval (1MIN-HIIT), high-intensity interval (2MIN-HIIT) or control groups. 1MIN-HIIT and 2MIN-HIIT completed 3 weeks of cycling interval training, 3 days/week, consisting of either 10 × 1 min bouts at 90% PO with 1 min rests (1MIN-HIIT) or 5 × 2 min bouts with 1 min rests at undulating intensities (80%-100%) (2MIN-HIIT). There were no significant training effects on FM (Δ1.06 ± 1.25 kg) or %BF (Δ1.13% ± 1.88%), compared to CON. Increases in LM were not significant but increased by 1.7 kg and 2.1 kg for 1MIN and 2MIN-HIIT groups, respectively. Increases in VO2peak were also not significant for 1MIN (3.4 ml·kg(-1) · min(-1)) or 2MIN groups (2.7 ml · kg(-1) · min(-1)). IN sensitivity (HOMA-IR) improved for both training groups (Δ-2.78 ± 3.48 units; p HIIT may be an effective short-term strategy to improve cardiorespiratory fitness and IN sensitivity in overweight males.

  15. Interbirth interval is associated with childhood type 1 diabetes risk

    DEFF Research Database (Denmark)

    Cardwell, Chris R; Svensson, Jannet; Waldhoer, Thomas

    2012-01-01

    Short interbirth interval has been associated with maternal complications and childhood autism and leukemia, possibly due to deficiencies in maternal micronutrients at conception or increased exposure to sibling infections. A possible association between interbirth interval and subsequent risk...

  16. VT Mile Points - 1/10-Mile Intervals

    Data.gov (United States)

    Vermont Center for Geographic Information — The mile points data layer is comprised of discrete locations based on specific measured intervals along a route. These intervals are represented along a...

  17. A Note on Inclusion Intervals of Matrix Singular Values

    OpenAIRE

    Cui, Shu-Yu; Tian, Gui-Xian

    2012-01-01

    We establish an inclusion relation between two known inclusion intervals of matrix singular values in some special case. In addition, based on the use of positive scale vectors, a known inclusion interval of matrix singular values is also improved.

  18. Two-sorted Point-Interval Temporal Logics

    DEFF Research Database (Denmark)

    Balbiani, Philippe; Goranko, Valentin; Sciavicco, Guido

    2011-01-01

    There are two natural and well-studied approaches to temporal ontology and reasoning: point-based and interval-based. Usually, interval-based temporal reasoning deals with points as particular, duration-less intervals. Here we develop explicitly two-sorted point-interval temporal logical framework...... whereby time instants (points) and time periods (intervals) are considered on a par, and the perspective can shift between them within the formal discourse. We focus on fragments involving only modal operators that correspond to the inter-sort relations between points and intervals. We analyze...... their expressiveness, comparative to interval-based logics, and the complexity of their satisfiability problems. In particular, we identify some previously not studied and potentially interesting interval logics. © 2011 Elsevier B.V....

  19. Traces of times past : Representations of temporal intervals in memory

    NARCIS (Netherlands)

    Taatgen, Niels; van Rijn, Hedderik

    2011-01-01

    Theories of time perception typically assume that some sort of memory represents time intervals. This memory component is typically underdeveloped in theories of time perception. Following earlier work that suggested that representations of different time intervals contaminate each other (Grondin,

  20. Numerical calculation of economic uncertainty by intervals and fuzzy numbers

    DEFF Research Database (Denmark)

    Schjær-Jacobsen, Hans

    2010-01-01

    This paper emphasizes that numerically correct calculation of economic uncertainty with intervals and fuzzy numbers requires implementation of global optimization techniques in contrast to straightforward application of interval arithmetic. This is demonstrated by both a simple case from managerial...

  1. An Interval Bound Algorithm of optimizing reactor core loading pattern by using reactivity interval schema

    International Nuclear Information System (INIS)

    Gong Zhaohu; Wang Kan; Yao Dong

    2011-01-01

    Highlights: → We present a new Loading Pattern Optimization method - Interval Bound Algorithm (IBA). → IBA directly uses the reactivity of fuel assemblies and burnable poison. → IBA can optimize fuel assembly orientation in a coupled way. → Numerical experiment shows that IBA outperforms genetic algorithm and engineers. → We devise DDWF technique to deal with multiple objectives and constraints. - Abstract: In order to optimize the core loading pattern in Nuclear Power Plants, the paper presents a new optimization method - Interval Bound Algorithm (IBA). Similar to the typical population based algorithms, e.g. genetic algorithm, IBA maintains a population of solutions and evolves them during the optimization process. IBA acquires the solution by statistical learning and sampling the control variable intervals of the population in each iteration. The control variables are the transforms of the reactivity of fuel assemblies or the worth of burnable poisons, which are the crucial heuristic information for loading pattern optimization problems. IBA can deal with the relationship between the dependent variables by defining the control variables. Based on the IBA algorithm, a parallel Loading Pattern Optimization code, named IBALPO, has been developed. To deal with multiple objectives and constraints, the Dynamic Discontinuous Weight Factors (DDWF) for the fitness function have been used in IBALPO. Finally, the code system has been used to solve a realistic reloading problem and a better pattern has been obtained compared with the ones searched by engineers and genetic algorithm, thus the performance of the code is proved.

  2. Application of the entropic coefficient for interval number optimization during interval assessment

    Directory of Open Access Journals (Sweden)

    Tynynyka A. N.

    2017-06-01

    Full Text Available In solving many statistical problems, the most precise choice of the distribution law of a random variable is required, the sample of which the authors observe. This choice requires the construction of an interval series. Therefore, the problem arises of assigning an optimal number of intervals, and this study proposes a number of formulas for solving it. Which of these formulas solves the problem more accurately? In [9], this question is investigated using the Pearson criterion. This article describes the procedure and on its basis gives formulas available in literature and proposed new formulas using the entropy coefficient. A comparison is made with the previously published results of applying Pearson's concord criterion for these purposes. Differences in the estimates of the accuracy of the formulas are found. The proposed new formulas for calculating the number of intervals showed the best results. Calculations have been made to compare the work of the same formulas for the distribution of sample data according to the normal law and the Rayleigh law.

  3. Forgetting Curve: Experiments on Intervals and Total Time in Recall

    OpenAIRE

    Ping Zhan; Jeffrey Hanks

    2015-01-01

    This manuscript is a continuation of our previous work ([1], [2]). In [1], we mainly tested the spacing effect and whether intervals affect the recall ratio in recalling English words. From the forgetting curve, learning data like English words and their definitions, it has been assumed that initial intervals should be shorter than later ones. But our experiments showed that the ratio of remembered words is not related to the patterns of intervals, (1) initial intervals shorter than later one...

  4. RCPAQAP First Combined Measurement and Reference Interval Survey

    OpenAIRE

    Jones, Graham RD; Koetsier, Sabrina DA

    2014-01-01

    Reference intervals are commonly considered to allow for between-laboratory bias. The RCPAQAP Liquid Serum Chemistry Program has collected data on laboratory measurements as well as reference intervals. This allows assessment of the between-laboratory variation in results, reference intervals and the information transmitted by the combination of these factors. For the majority of common chemistry analytes, the between-laboratory variation in reference intervals is greater than the variation i...

  5. Overestimation of the second time interval replaces time-shrinking when the difference between two adjacent time intervals increases

    Directory of Open Access Journals (Sweden)

    Yoshitaka eNakajima

    2014-05-01

    Full Text Available When the onsets of three successive sound bursts mark two adjacent time intervals, the second time interval can be underestimated when it is physically longer than the first time interval by up to 100 ms. This illusion, time-shrinking, is very stable when the first time interval is 200 ms or shorter (Nakajima et al., 2004, Perception, 33. Time-shrinking had been considered a kind of perceptual assimilation to make the first and the second time interval more similar to each other. Here we investigated whether the underestimation of the second time interval was replaced by an overestimation if the physical difference between the neighboring time intervals was too large for the assimilation to take place; this was a typical situation in which a perceptual contrast could be expected. Three experiments to measure the overestimation/underestimation of the second time interval by the method of adjustment were conducted. The first time interval was varied from 40 to 280 ms, and such overestimations indeed took place when the first time interval was 80-280 ms. The overestimations were robust when the second time interval was longer than the first time interval by 240 ms or more, and the magnitude of the overestimation was larger than 100 ms in some conditions. Thus, a perceptual contrast to replace time-shrinking was established. An additional experiment indicated that this contrast did not affect the perception of the first time interval substantially: The contrast in the present conditions seemed unilateral.

  6. Clustering and classification of music using interval categories

    NARCIS (Netherlands)

    Honingh, A.; Bod, R.

    2011-01-01

    We present a novel approach to clustering and classification of music, based on the concept of interval categories. Six interval categories exist, each with its own musical character. A piece of music can be represented by six numbers, reflecting the percentages of occurrences of each interval

  7. Rigorous Verification for the Solution of Nonlinear Interval System ...

    African Journals Online (AJOL)

    We survey a general method for solving nonlinear interval systems of equations. In particular, we paid special attention to the computational aspects of linear interval systems since the bulk of computations are done during the stage of computing outer estimation of the including linear interval systems. The height of our ...

  8. A method to elicit beliefs as most likely intervals

    NARCIS (Netherlands)

    Schlag, K.H.; van der Weele, J.J.

    2015-01-01

    We show how to elicit the beliefs of an expert in the form of a "most likely interval", a set of future outcomes that are deemed more likely than any other outcome. Our method, called the Most Likely Interval elicitation rule (MLI), asks the expert for an interval and pays according to how well the

  9. DEVELOPMENT MANAGEMENT TRANSFER PRICING BY APPLICATION OF THE INTERVAL ESTIMATES

    Directory of Open Access Journals (Sweden)

    Elena B. Shuvalova

    2013-01-01

    Full Text Available The article discusses the application of the method of interval estimation of conformity of the transaction price the market price. A comparative analysis of interval and point estimate. Identified the positive and negative effects of using interval estimation.

  10. A filtering method for the interval eigenvalue problem

    DEFF Research Database (Denmark)

    Hladik, Milan; Daney, David; Tsigaridas, Elias

    2011-01-01

    We consider the general problem of computing intervals that contain the real eigenvalues of interval matrices. Given an outer approximation (superset) of the real eigenvalue set of an interval matrix, we propose a filtering method that iteratively improves the approximation. Even though our method...

  11. Learning about confidence intervals with software R

    Directory of Open Access Journals (Sweden)

    Gariela Gonçalves

    2013-08-01

    Full Text Available 0 0 1 202 1111 USAL 9 2 1311 14.0 Normal 0 21 false false false ES JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:Calibri; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-ansi-language:ES; mso-fareast-language:EN-US;} This work was to study the feasibility of implementing a teaching method that employs software, in a Computational Mathematics course, involving students and teachers through the use of the statistical software R in carrying out practical work, such as strengthening the traditional teaching. The statistical inference, namely the determination of confidence intervals, was the content selected for this experience. It was intended show, first of all, that it is possible to promote, through the proposal methodology, the acquisition of basic skills in statistical inference and to promote the positive relationships between teachers and students. It presents also a comparative study between the methodologies used and their quantitative and qualitative results on two consecutive school years, in several indicators. The data used in the study were obtained from the students to the exam questions in the years 2010/2011 and 2011/2012, from the achievement of a working group in 2011/2012 and via the responses to a questionnaire (optional and anonymous also applied in 2011 / 2012. In terms of results, we emphasize a better performance of students in the examination questions in 2011/2012, the year that students used the software R, and a very favorable student’s perspective about

  12. RR-Interval variance of electrocardiogram for atrial fibrillation detection

    Science.gov (United States)

    Nuryani, N.; Solikhah, M.; Nugoho, A. S.; Afdala, A.; Anzihory, E.

    2016-11-01

    Atrial fibrillation is a serious heart problem originated from the upper chamber of the heart. The common indication of atrial fibrillation is irregularity of R peak-to-R-peak time interval, which is shortly called RR interval. The irregularity could be represented using variance or spread of RR interval. This article presents a system to detect atrial fibrillation using variances. Using clinical data of patients with atrial fibrillation attack, it is shown that the variance of electrocardiographic RR interval are higher during atrial fibrillation, compared to the normal one. Utilizing a simple detection technique and variances of RR intervals, we find a good performance of atrial fibrillation detection.

  13. Assessing QT interval prolongation and its associated risks with antipsychotics

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Graff, Claus; Kanters, Jørgen K.

    2011-01-01

    manifesting antipsychotic-associated TdP and subsequently SCD have well established risk factors for SCD, i.e. older age, female gender, hypokalaemia and cardiovascular disease. QT interval prolongation is the most widely used surrogate marker for assessing the risk of TdP but it is considered somewhat...... imprecise, partly because QT interval changes are subject to measurement error. In particular, drug-induced T-wave changes (e.g. flattening of the T-wave) may complicate the measurement of the QT interval. Furthermore, the QT interval depends on the heart rate and a corrected QT (QTc) interval is often used...

  14. Volatility return intervals analysis of the Japanese market

    Science.gov (United States)

    Jung, W.-S.; Wang, F. Z.; Havlin, S.; Kaizoji, T.; Moon, H.-T.; Stanley, H. E.

    2008-03-01

    We investigate scaling and memory effects in return intervals between price volatilities above a certain threshold q for the Japanese stock market using daily and intraday data sets. We find that the distribution of return intervals can be approximated by a scaling function that depends only on the ratio between the return interval τ and its mean . We also find memory effects such that a large (or small) return interval follows a large (or small) interval by investigating the conditional distribution and mean return interval. The results are similar to previous studies of other markets and indicate that similar statistical features appear in different financial markets. We also compare our results between the period before and after the big crash at the end of 1989. We find that scaling and memory effects of the return intervals show similar features although the statistical properties of the returns are different.

  15. Effects of Methylphenidate and Atomoxetine on Cortical Inhibition in ADHD

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2006-09-01

    Full Text Available The effects of methylphenidate (MPH, a psychostimulant, and atomoxetine (ATX, a selective norepinephrine reuptake inhibitor, on short interval-cortical inhibition (SICI were measured in motor cortex with transcranial magnetic stimulation, in a study at Cincinnati Children’s Medical Center, OH, and other centers.

  16. Confidence Intervals: From tests of statistical significance to confidence intervals, range hypotheses and substantial effects

    Directory of Open Access Journals (Sweden)

    Dominic Beaulieu-Prévost

    2006-03-01

    Full Text Available For the last 50 years of research in quantitative social sciences, the empirical evaluation of scientific hypotheses has been based on the rejection or not of the null hypothesis. However, more than 300 articles demonstrated that this method was problematic. In summary, null hypothesis testing (NHT is unfalsifiable, its results depend directly on sample size and the null hypothesis is both improbable and not plausible. Consequently, alternatives to NHT such as confidence intervals (CI and measures of effect size are starting to be used in scientific publications. The purpose of this article is, first, to provide the conceptual tools necessary to implement an approach based on confidence intervals, and second, to briefly demonstrate why such an approach is an interesting alternative to an approach based on NHT. As demonstrated in the article, the proposed CI approach avoids most problems related to a NHT approach and can often improve the scientific and contextual relevance of the statistical interpretations by testing range hypotheses instead of a point hypothesis and by defining the minimal value of a substantial effect. The main advantage of such a CI approach is that it replaces the notion of statistical power by an easily interpretable three-value logic (probable presence of a substantial effect, probable absence of a substantial effect and probabilistic undetermination. The demonstration includes a complete example.

  17. The different effects of high intensity interval training and moderate intensity interval training for weightlessness countermeasures

    Science.gov (United States)

    Wang, Lin-Jie; Cheng, Tan; Zhi-Li, Li; Hui-juan, Wang; Wen-juan, Chen; Jianfeng, Zhang; Desheng, Wang; Dongbin, Niu; Qi, Zhao; Chengjia, Yang; Yanqing, Wang

    High intensity interval training (HIIT) has been demonstrated to improve performance in a relatively short training period. But the difference between high intensity interval training and moderate intensity interval training (MIIT) in simulated weightlessness still has not been well studied. This study sought to characterize the difference between 6 weeks high intensity interval training and moderate intensity interval training under reduced weight (RW) gait training device and zero-gravity locomotion system (ZLS). Twenty-three subjects (14M/4F, 32.5±4.5 years) volunteered to participate. They were divided into three groups, that were MITT (alternating 2 min at 40% VO _{2} peak and 2 min at 60% VO _{2} peak for 30min, five days per week) RW group (n=8), HITT (alternating 2 min at 40% VO _{2} peak and 2 min at 90% VO _{2} peak for 30min, three days per week) RW group (n=8) and HITT ZLS group (n=7). The Z-axis load used in RW group was 80% body weight (BW) and in ZLS was 100% BW. Cardiopulmonary function was measured before, after 4-week training and after 6-week training. Isokinetic knee extension-flexion test at 60(°) deg/s and 180(°) deg/s were performed before and after the 6-week training, and isometric knee extension-flexion test at 180(°) deg/s was also examined at the same time. It was found that the VO _{2} peaks, metabolic equivalent (MET), Speedmax and respiratory exchange ratio (RER) were significantly increased after 4 and 6-week training in all three groups and no significant group difference were detected. The peak torque at 60(°) deg/s for right knee flexion were significantly increased after 6 week-training in all three groups, and only in HITT RW group the total power at 60(°) deg/s for right knee flexion enhanced. The total power and average power at 60(°) deg/s for right knee extension decreased significantly after 6-week training in all three groups. The peak torque at 60(°) deg/s for right knee extension in MIIT RW group was

  18. Tuning for temporal interval in human apparent motion detection.

    Science.gov (United States)

    Bours, Roger J E; Stuur, Sanne; Lankheet, Martin J M

    2007-01-08

    Detection of apparent motion in random dot patterns requires correlation across time and space. It has been difficult to study the temporal requirements for the correlation step because motion detection also depends on temporal filtering preceding correlation and on integration at the next levels. To specifically study tuning for temporal interval in the correlation step, we performed an experiment in which prefiltering and postintegration were held constant and in which we used a motion stimulus containing coherent motion for a single interval value only. The stimulus consisted of a sparse random dot pattern in which each dot was presented in two frames only, separated by a specified interval. On each frame, half of the dots were refreshed and the other half was a displaced reincarnation of the pattern generated one or several frames earlier. Motion energy statistics in such a stimulus do not vary from frame to frame, and the directional bias in spatiotemporal correlations is similar for different interval settings. We measured coherence thresholds for left-right direction discrimination by varying motion coherence levels in a Quest staircase procedure, as a function of both step size and interval. Results show that highest sensitivity was found for an interval of 17-42 ms, irrespective of viewing distance. The falloff at longer intervals was much sharper than previously described. Tuning for temporal interval was largely, but not completely, independent of step size. The optimal temporal interval slightly decreased with increasing step size. Similarly, the optimal step size decreased with increasing temporal interval.

  19. QT interval prolongation after sertraline overdose: a case report

    Directory of Open Access Journals (Sweden)

    Holman Nicole D

    2005-07-01

    Full Text Available Abstract Background Selective serotonin reuptake inhibitors (SSRIs are the most common antidepressants used in first-world countries and are generally well tolerated. Specifically, less cardiovascular toxicity has been reported in comparison with tricyclic antidepressants. Here we report QT interval prolongation after an overdose of the SSRI sertraline. Case presentation A previously healthy female patient presented with an attempted suicide with overdoses sertraline (2250 mg, diazepam (200 mg, and temazepam (400 mg. Routine laboratory studies were normal and her ECG upon admission showed a normal QT interval. The next day, her ECG showed prolongation of the QTc interval up to 525 ms. After discontinuation of sertraline the QT interval normalized. Echocardiography and exercise electrocardiography were normal. After hospitalization, the patient resumed sertraline in the normally recommended dose and QT interval remained within normal ranges. Conclusion It seems that the SSRI sertraline in overdose may cause QT interval prolongation.

  20. Contrasting Diversity Values: Statistical Inferences Based on Overlapping Confidence Intervals

    Science.gov (United States)

    MacGregor-Fors, Ian; Payton, Mark E.

    2013-01-01

    Ecologists often contrast diversity (species richness and abundances) using tests for comparing means or indices. However, many popular software applications do not support performing standard inferential statistics for estimates of species richness and/or density. In this study we simulated the behavior of asymmetric log-normal confidence intervals and determined an interval level that mimics statistical tests with P(α) = 0.05 when confidence intervals from two distributions do not overlap. Our results show that 84% confidence intervals robustly mimic 0.05 statistical tests for asymmetric confidence intervals, as has been demonstrated for symmetric ones in the past. Finally, we provide detailed user-guides for calculating 84% confidence intervals in two of the most robust and highly-used freeware related to diversity measurements for wildlife (i.e., EstimateS, Distance). PMID:23437239

  1. Risk prediction of cardiovascular death based on the QTc interval

    DEFF Research Database (Denmark)

    Nielsen, Jonas B; Graff, Claus; Rasmussen, Peter V

    2014-01-01

    interval resulted in the worst prognosis for men whereas in women, a very short QTc interval was equivalent in risk to a borderline prolonged QTc interval. The effect of the QTc interval on the absolute risk of CVD was most pronounced in the elderly and in those with cardiovascular disease whereas.......1 years, 6647 persons died from cardiovascular causes. Long-term risks of CVD were estimated for subgroups defined by age, gender, cardiovascular disease, and QTc interval categories. In general, we observed an increased risk of CVD for both very short and long QTc intervals. Prolongation of the QTc...... the effect was negligible for middle-aged women without cardiovascular disease. The most important improvement in prediction accuracy was noted for women aged 70-90 years. In this subgroup, a total of 9.5% were reclassified (7.2% more accurately vs. 2.3% more inaccurately) within clinically relevant 5-year...

  2. Reference intervals for the P-Albumin bromocresol purple method.

    Science.gov (United States)

    Christensen, Peter Astrup

    2017-10-01

    Correct reference intervals are an important part of test results. As establishing own reference intervals is a very expensive task, the NORIP reference intervals are often transferred for use in Nordic laboratories. The NORIP reference interval on P-Albumin was here compared to current results for laboratories using the bromocresol purple (BCP) method for P-Albumin. External quality control reports were used to investigate the change in levels between the BCP and BCG methods on P-Albumin. An algorithm was built for extracting and isolating the laboratory's healthy subject population. The algorithm was used to extract test results from the laboratory information system. Parametric and non-parametric statistical methods were used to evaluate the P-Albumin test result populations. The indirect method used here clearly shows that the NORIP reference intervals for P-Albumin are not fit for the current bromocresol purple methods. The method was also used to suggest new reference interval limits.

  3. Perception of short time scale intervals in a hypnotic virtuoso.

    Science.gov (United States)

    Noreika, Valdas; Falter, Christine M; Arstila, Valtteri; Wearden, John H; Kallio, Sakari

    2012-01-01

    Previous studies showed that hypnotized individuals underestimate temporal intervals in the range of several seconds to tens of minutes. However, no previous work has investigated whether duration perception is equally disorderly when shorter time intervals are probed. In this study, duration perception of a hypnotic virtuoso was tested using repeated standard temporal generalization and duration estimation tasks. When compared to the baseline state, hypnosis affected perception of intervals spread around 600 ms in the temporal generalization task but did not alter perception of slightly longer intervals spread around 1000 ms. Furthermore, generalization of temporal intervals was more orderly under hypnosis than in the baseline state. In contrast, the hypnotic virtuoso showed a typical time underestimation effect when perception of longer supra-second intervals was tested in the duration estimation task, replicating results of the previous hypnosis studies.

  4. Reference intervals data mining: no longer a probability paper method.

    Science.gov (United States)

    Katayev, Alexander; Fleming, James K; Luo, Dajie; Fisher, Arren H; Sharp, Thomas M

    2015-01-01

    To describe the application of a data-mining statistical algorithm for calculation of clinical laboratory tests reference intervals. Reference intervals for eight different analytes and different age and sex groups (a total of 11 separate reference intervals) for tests that are unlikely to be ordered during routine screening of disease-free populations were calculated using the modified algorithm for data mining of test results stored in the laboratory database and compared with published peer-reviewed studies that used direct sampling. The selection of analytes was based on the predefined criteria that include comparability of analytical methods with a statistically significant number of observations. Of the 11 calculated reference intervals, having upper and lower limits for each, 21 of 22 reference interval limits were not statistically different from the reference studies. The presented statistical algorithm is shown to be an accurate and practical tool for reference interval calculations. Copyright© by the American Society for Clinical Pathology.

  5. Propositional interval neighborhood logics: Expressiveness, decidability, and undecidable extensions

    DEFF Research Database (Denmark)

    Bresolin, Davide; Goranko, Valentin; Montanari, Angelo

    2009-01-01

    In this paper, we investigate the expressiveness of the variety of propositional interval neighborhood logics (PNL), we establish their decidability on linearly ordered domains and some important subclasses, and we prove the undecidability of a number of extensions of PNL with additional modalities...... over interval relations. All together, we show that PNL form a quite expressive and nearly maximal decidable fragment of Halpern–Shoham’s interval logic HS....

  6. The Interval Stability of an Electricity Market Model

    Directory of Open Access Journals (Sweden)

    Weijuan Wang

    2014-01-01

    Full Text Available Combined with the electric power market dynamic model put forward by Alvarado, an interval model of electricity markets is established and investigated in this paper pertaining to the range of demand elasticity with suppliers and consumers. The stability of an electricity market framework with demand elasticity interval is analyzed. The conclusions characterizing the interval model provided are derived by constructing a suitable Lyapunov function and using the theory of interval dynamical system in differential equations and matrix inequality theory and so forth. Applying the corollary obtained can judge the system stability by available data about demand elasticity. The obtained results are validated and illustrated by a case example.

  7. Clinical and Biological Features of Interval Colorectal Cancer

    Directory of Open Access Journals (Sweden)

    Yu Mi Lee

    2017-05-01

    Full Text Available Interval colorectal cancer (I-CRC is defined as a CRC diagnosed within 60 months after a negative colonoscopy, taking into account that 5 years is the “mean sojourn time.” It is important to prevent the development of interval cancer. The development of interval colon cancer is associated with female sex, old age, family history of CRC, comorbidities, diverticulosis, and the skill of the endoscopist. During carcinogenesis, sessile serrated adenomas/polyps (SSA/Ps share many genomic and colonic site characteristics with I-CRCs. The clinical and biological features of I-CRC should be elucidated to prevent the development of interval colon cancer.

  8. Closing the Gaps in Paediatric Reference Intervals: The CALIPER Initiative

    Science.gov (United States)

    Schnabl, Kareena; Chan, Man Khun; Gong, Yanping; Adeli, Khosrow

    2008-01-01

    Screening, diagnosis and monitoring of paediatric diseases relies on the measurement of a spectrum of disease biomarkers in clinical laboratories to guide important clinical decisions. Physicians rely on the availability of suitable and reliable reference intervals to accurately interpret laboratory test results with data collected during medical history and physical examination. However, critical gaps currently exist in accurate and up-to-date reference intervals (normal values) for accurate interpretation of laboratory tests performed in children and adolescents. These gaps in the available paediatric laboratory reference intervals have the clear potential of contributing to erroneous diagnosis or misdiagnosis of many diseases of childhood and adolescence. Most of the available reference intervals for laboratory tests were determined over two decades ago on older instruments and technologies, and are no longer relevant considering the current testing technology used by clinical laboratories. It is thus critical and of utmost urgency that a more acceptable and comprehensive database be established. There are however many challenges when attempting to establish paediatric reference intervals. Paediatric specimen collection is a major concern for health care providers as it is frequently difficult to obtain sufficient volumes of blood or urine from paediatric patients. Common reference intervals have not been widely implemented due to lack of harmonisation of methods and differences in patient populations. Consequently, clinical laboratory accreditation organisations and licensing agencies require that each laboratory verify or establish reference intervals for each method. To provide such reference intervals requires selection criteria for suitable reference individuals, defined conditions for specimen collection and analysis, method selection to determine reference limits and validation of the reference interval. The current review will provide a brief

  9. Comparing interval estimates for small sample ordinal CFA models.

    Science.gov (United States)

    Natesan, Prathiba

    2015-01-01

    Robust maximum likelihood (RML) and asymptotically generalized least squares (AGLS) methods have been recommended for fitting ordinal structural equation models. Studies show that some of these methods underestimate standard errors. However, these studies have not investigated the coverage and bias of interval estimates. An estimate with a reasonable standard error could still be severely biased. This can only be known by systematically investigating the interval estimates. The present study compares Bayesian, RML, and AGLS interval estimates of factor correlations in ordinal confirmatory factor analysis models (CFA) for small sample data. Six sample sizes, 3 factor correlations, and 2 factor score distributions (multivariate normal and multivariate mildly skewed) were studied. Two Bayesian prior specifications, informative and relatively less informative were studied. Undercoverage of confidence intervals and underestimation of standard errors was common in non-Bayesian methods. Underestimated standard errors may lead to inflated Type-I error rates. Non-Bayesian intervals were more positive biased than negatively biased, that is, most intervals that did not contain the true value were greater than the true value. Some non-Bayesian methods had non-converging and inadmissible solutions for small samples and non-normal data. Bayesian empirical standard error estimates for informative and relatively less informative priors were closer to the average standard errors of the estimates. The coverage of Bayesian credibility intervals was closer to what was expected with overcoverage in a few cases. Although some Bayesian credibility intervals were wider, they reflected the nature of statistical uncertainty that comes with the data (e.g., small sample). Bayesian point estimates were also more accurate than non-Bayesian estimates. The results illustrate the importance of analyzing coverage and bias of interval estimates, and how ignoring interval estimates can be misleading

  10. A probabilistic approach for representation of interval uncertainty

    International Nuclear Information System (INIS)

    Zaman, Kais; Rangavajhala, Sirisha; McDonald, Mark P.; Mahadevan, Sankaran

    2011-01-01

    In this paper, we propose a probabilistic approach to represent interval data for input variables in reliability and uncertainty analysis problems, using flexible families of continuous Johnson distributions. Such a probabilistic representation of interval data facilitates a unified framework for handling aleatory and epistemic uncertainty. For fitting probability distributions, methods such as moment matching are commonly used in the literature. However, unlike point data where single estimates for the moments of data can be calculated, moments of interval data can only be computed in terms of upper and lower bounds. Finding bounds on the moments of interval data has been generally considered an NP-hard problem because it includes a search among the combinations of multiple values of the variables, including interval endpoints. In this paper, we present efficient algorithms based on continuous optimization to find the bounds on second and higher moments of interval data. With numerical examples, we show that the proposed bounding algorithms are scalable in polynomial time with respect to increasing number of intervals. Using the bounds on moments computed using the proposed approach, we fit a family of Johnson distributions to interval data. Furthermore, using an optimization approach based on percentiles, we find the bounding envelopes of the family of distributions, termed as a Johnson p-box. The idea of bounding envelopes for the family of Johnson distributions is analogous to the notion of empirical p-box in the literature. Several sets of interval data with different numbers of intervals and type of overlap are presented to demonstrate the proposed methods. As against the computationally expensive nested analysis that is typically required in the presence of interval variables, the proposed probabilistic representation enables inexpensive optimization-based strategies to estimate bounds on an output quantity of interest.

  11. A scoping review of the psychological responses to interval exercise: is interval exercise a viable alternative to traditional exercise?

    Science.gov (United States)

    Stork, Matthew J; Banfield, Laura E; Gibala, Martin J; Martin Ginis, Kathleen A

    2017-12-01

    While considerable evidence suggests that interval exercise confers numerous physiological adaptations linked to improved health, its psychological consequences and behavioural implications are less clear and the subject of intense debate. The purpose of this scoping review was to catalogue studies investigating the psychological responses to interval exercise in order to identify what psychological outcomes have been assessed, the research methods used, and the results. A secondary objective was to identify research issues and gaps. Forty-two published articles met the review inclusion/exclusion criteria. These studies involved 1258 participants drawn from various active/inactive and healthy/unhealthy populations, and 55 interval exercise protocols (69% high-intensity interval training [HIIT], 27% sprint interval training [SIT], and 4% body-weight interval training [BWIT]). Affect and enjoyment were the most frequently studied psychological outcomes. Post-exercise assessments indicate that overall, enjoyment of, and preferences for interval exercise are equal or greater than for continuous exercise, and participants can hold relatively positive social cognitions regarding interval exercise. Although several methodological issues (e.g., inconsistent use of terminology, measures and protocols) and gaps (e.g., data on adherence and real-world protocols) require attention, from a psychological perspective, the emerging data support the viability of interval exercise as an alternative to continuous exercise.

  12. Drug discrimination under two concurrent fixed-interval fixed-interval schedules.

    Science.gov (United States)

    McMillan, D E; Li, M

    2000-07-01

    Pigeons were trained to discriminate 5.0 mg/kg pentobarbital from saline under a two-key concurrent fixed-interval (FI) 100-s FI 200-s schedule of food presentation, and later tinder a concurrent FI 40-s FI 80-s schedule, in which the FI component with the shorter time requirement reinforced responding on one key after drug administration (pentobarbital-biased key) and on the other key after saline administration (saline-biased key). After responding stabilized under the concurrent FI 100-s FI 200-s schedule, pigeons earned an average of 66% (after pentobarbital) to 68% (after saline) of their reinforcers for responding under the FI 100-s component of the concurrent schedule. These birds made an average of 70% of their responses on both the pentobarbital-biased key after the training dose of pentobarbital and the saline-biased key after saline. After responding stabilized under the concurrent FI 40-s FI 80-s schedule, pigeons earned an average of 67% of their reinforcers for responding under the FI 40 component after both saline and the training dose of pentobarbital. These birds made an average of 75% of their responses on the pentobarbital-biased key after the training dose of pentobarbital, but only 55% of their responses on the saline-biased key after saline. In test sessions preceded by doses of pentobarbital, chlordiazepoxide, ethanol, phencyclidine, or methamphetamine, the dose-response curves were similar under these two concurrent schedules. Pentobarbital, chlordiazepoxide, and ethanol produced dose-dependent increases in responding on the pentobarbital-biased key as the doses increased. For some birds, at the highest doses of these drugs, the dose-response curve turned over. Increasing doses of phencyclidine produced increased responding on the pentobarbital-biased key in some, but not all, birds. After methamphetamine, responding was largely confined to the saline-biased key. These data show that pigeons can perform drug discriminations under concurrent

  13. Lactation yield: Interval level comparison of milk records for genetic ...

    African Journals Online (AJOL)

    Milk recording intervals was studied by analysing 1220 lactation records of Friesian x Arsi crossbred cows kept in south eastern highlands of Ethiopia. Milk Recording Intervals (MRI) comparison was made at 15, 30 and 45 day's length. Accuracy was measured in terms of percentage difference between actual and estimated ...

  14. Inter-pregnancy interval and pregnancy outcomes among HIV ...

    African Journals Online (AJOL)

    Background: Both short and long inter-pregnancy intervals have been associated with higher risk of adverse pregnancy outcomes. More so, short interpregnancy interval among HIVpositive women implies higher birth rate and subsequently a higher number of neonates exposed to HIV and potentially at r i s k o f mo t h e r ...

  15. A note on Nonparametric Confidence Interval for a Shift Parameter ...

    African Journals Online (AJOL)

    In this article an application of a kernel based nonparametric approach in constructing a large sample nonparametric confidence interval for a shift parameter is considered. The method is illustrated using the Cauchy distribution as a location model. The kernel-based method is found to have a shorter interval for the shift ...

  16. Birth interval and its predictors among married women in Dabat ...

    African Journals Online (AJOL)

    2008-12-30

    Birth intervals (time between two successive live births) if short are associated with diverse complications. We assessed birth interval and its predictors among 613 married women who gave birth from January 1 to December 30, 2008. Data were collected in April 2012. Life table and Kaplan-Meier curve were used to ...

  17. Evaluation of Healing Intervals of Incisional Skin Wounds of Goats ...

    African Journals Online (AJOL)

    The aim of this study was to compare the healing intervals among simple interrupted (SI), ford interlocking (FI) and subcuticular (SC) suture patterns in goats. We hypothesized that these common suture patterns used for closure of incisional skin wounds may have effect on the healing interval. To test this hypothesis, two ...

  18. An Analysis Of QRS Interval Of The Electrocardiogram In ...

    African Journals Online (AJOL)

    Objectives: This cross-sectional study of the 12-lead electrocardiogram (ECG) was undertaken to establish the normal QRS interval of the adult Nigerian from Jos; to find significant correlation coefficients for QRS interval and the various anthropometric measurements and also to establish prediction equations for the QRS ...

  19. Inter-pregnancy interval and pregnancy outcomes among HIV ...

    African Journals Online (AJOL)

    owner

    Abstract Background: Both short and long inter-pregnancy intervals have been associated with higher risk of adverse pregnancy outcomes. More so, short inter- pregnancy interval among HIV- positive women implies higher birth rate and subsequently a higher number of neonates exposed to HIV and potentially at.

  20. An approximate confidence interval for recombination fraction in ...

    African Journals Online (AJOL)

    user

    2011-02-14

    Feb 14, 2011 ... proposed a two stage Markov Chain Monte Carlo (MCMC) method to calculate an approximate confidence interval (ACI) ... Key words: Markov Chain Monte Carlo (MCMC), Gibbs sampler, approximate confidence interval, simulation size. ... from local conditional distributions at parameter valuesθ , given the ...

  1. Reference intervals for serum total cholesterol, HDL cholesterol and ...

    African Journals Online (AJOL)

    Reference intervals of total cholesterol, HDL cholesterol and non-HDL cholesterol concentrations were determined on 309 blood donors from an urban and peri-urban population of Botswana. Using non-parametric methods to establish 2.5th and 97.5th percentiles of the distribution, the intervals were: total cholesterol 2.16 ...

  2. Similar expression of oxidative genes after interval and continuous exercise

    DEFF Research Database (Denmark)

    Wang, Li; Psilander, Niklas; Tonkonogi, Michail

    2009-01-01

    PURPOSE: There is a debate whether interval or traditional endurance training is the most effective stimulus of mitochondrial biogenesis. Here, we compared the effects of acute interval exercise (IE) or continuous exercise (CE) on the muscle messenger RNA (mRNA) content for several genes involved...

  3. Integers without large prime factors in short intervals: Conditional ...

    Indian Academy of Sciences (India)

    Tenenbaum [HT93] and Pomerance [Po94] for highly readable and informative discus- sions on these topics. This article is about distribution of smooth numbers in short intervals, namely intervals of type (X, X +. √. X]. See the next subsection for basic facts about dis- tribution of smooth numbers. One expects that smooth ...

  4. Confidence Intervals for Effect Sizes: Applying Bootstrap Resampling

    Science.gov (United States)

    Banjanovic, Erin S.; Osborne, Jason W.

    2016-01-01

    Confidence intervals for effect sizes (CIES) provide readers with an estimate of the strength of a reported statistic as well as the relative precision of the point estimate. These statistics offer more information and context than null hypothesis statistic testing. Although confidence intervals have been recommended by scholars for many years,…

  5. Perception of short time scale intervals in a hypnotic virtuoso

    NARCIS (Netherlands)

    Noreika, Valdas; Falter, Christine M.; Arstila, Valtteri; Wearden, John H.; Kallio, Sakari

    2012-01-01

    Previous studies showed that hypnotized individuals underestimate temporal intervals in the range of several seconds to tens of minutes. However, no previous work has investigated whether duration perception is equally disorderly when shorter time intervals are probed. In this study, duration

  6. A Note on Inclusion Intervals of Matrix Singular Values

    Directory of Open Access Journals (Sweden)

    Shu-Yu Cui

    2012-01-01

    Full Text Available We establish an inclusion relation between two known inclusion intervals of matrix singular values in some special case. In addition, based on the use of positive scale vectors, a known inclusion interval of matrix singular values is also improved.

  7. Verified Interval Orbit Propagation in Satellite Collision Avoidance

    NARCIS (Netherlands)

    Römgens, B.A.; Mooij, E.; Naeije, M.C.

    2011-01-01

    Verified interval integration methods enclose a solution set corresponding to interval initial values and parameters, and bound integration and rounding errors. Verified methods suffer from overestimation of the solution, i.e., non-solutions are also included in the solution enclosure. Two verified

  8. Robotic fish tracking method based on suboptimal interval Kalman filter

    Science.gov (United States)

    Tong, Xiaohong; Tang, Chao

    2017-11-01

    Autonomous Underwater Vehicle (AUV) research focused on tracking and positioning, precise guidance and return to dock and other fields. The robotic fish of AUV has become a hot application in intelligent education, civil and military etc. In nonlinear tracking analysis of robotic fish, which was found that the interval Kalman filter algorithm contains all possible filter results, but the range is wide, relatively conservative, and the interval data vector is uncertain before implementation. This paper proposes a ptimization algorithm of suboptimal interval Kalman filter. Suboptimal interval Kalman filter scheme used the interval inverse matrix with its worst inverse instead, is more approximate nonlinear state equation and measurement equation than the standard interval Kalman filter, increases the accuracy of the nominal dynamic system model, improves the speed and precision of tracking system. Monte-Carlo simulation results show that the optimal trajectory of sub optimal interval Kalman filter algorithm is better than that of the interval Kalman filter method and the standard method of the filter.

  9. Rigorous Verification for the Solution of Nonlinear Interval System ...

    African Journals Online (AJOL)

    The height of our findings is the synchronization of Hansen's theorem with that due to Rohn to accelerate basic convergence characteristics of our method. We compare computed results with those obtained by Sainz et al where Kaucher interval arithmetic was applied on interval Jacobi iterative type method and found out ...

  10. Effect Of Interval Training On Blood Pressure And Exercise Capacity ...

    African Journals Online (AJOL)

    Effect Of Interval Training On Blood Pressure And Exercise Capacity In Hypertension: A Randomized Controlled Study. ... Tropical Journal of Health Sciences ... The primary purpose of the present study was to investigate the effect of interval training program on MAP in black African subjects with hypertension. Two hundred ...

  11. INTERVAL STATE ESTIMATION FOR SINGULAR DIFFERENTIAL EQUATION SYSTEMS WITH DELAYS

    Directory of Open Access Journals (Sweden)

    T. A. Kharkovskaia

    2016-07-01

    Full Text Available The paper deals with linear differential equation systems with algebraic restrictions (singular systems and a method of interval observer design for this kind of systems. The systems contain constant time delay, measurement noise and disturbances. Interval observer synthesis is based on monotone and cooperative systems technique, linear matrix inequations, Lyapunov function theory and interval arithmetic. The set of conditions that gives the possibility for interval observer synthesis is proposed. Results of synthesized observer operation are shown on the example of dynamical interindustry balance model. The advantages of proposed method are that it is adapted to observer design for uncertain systems, if the intervals of admissible values for uncertain parameters are given. The designed observer is capable to provide asymptotically definite limits on the estimation accuracy, since the interval of admissible values for the object state is defined at every instant. The obtained result provides an opportunity to develop the interval estimation theory for complex systems that contain parametric uncertainty, varying delay and nonlinear elements. Interval observers increasingly find applications in economics, electrical engineering, mechanical systems with constraints and optimal flow control.

  12. T(peak)T(end) interval in long QT syndrome

    DEFF Research Database (Denmark)

    Kanters, Jørgen Kim; Haarmark, Christian; Vedel-Larsen, Esben

    2008-01-01

    BACKGROUND: The T(peak)T(end) (T(p)T(e)) interval is believed to reflect the transmural dispersion of repolarization. Accordingly, it should be a risk factor in long QT syndrome (LQTS). The aim of the study was to determine the effect of genotype on T(p)T(e) interval and test whether it was related...

  13. Reference intervals for serum lipids in coastal males from Fangchenggang.

    Science.gov (United States)

    Qin, Xue; Mo, Cuiju; Zeng, Zhiyu; Chen, Zhiping; Deng, Yan; Peng, Qiliu; Gao, Yong; Yi, Zhen; Li, Shan; Mo, Zengnan

    2013-01-01

    We aimed to establish the reference intervals for serum lipids in coastal residents of the Chinese male population. A total of 1436 subjects, aged between 19 and 86 years, were selected from the Fangchenggang Area for Male Health and Examination Survey (FAMHES). Reference intervals of serum lipids were measured by enzymatic endpoint colorimetry and information was obtained using a standard questionnaire. The total nonparametric reference intervals for TC 1.90 mmol/L (73.08 mg/dL), and LDL-C serum lipid levels were correlated with older age, higher body mass index (BMI), and more smoking, but not with alcohol consumption. The established reference intervals of serum lipids for coastal Chinese male residents would be helpful for assessing risk of cardiovascular disease. We recommend establishing population-based reference intervals for serum lipids in clinical laboratories.

  14. BIOCHEMISTRY PANEL REFERENCE INTERVALS FOR JUVENILE GOLDFISH (CARASSIUS AURATUS).

    Science.gov (United States)

    Adamovicz, Laura A; Trosclair, Macy R; Lewbart, Gregory A

    2017-09-01

    Reference intervals for diagnostic tests are vitally important for clinical decision making. Despite the popularity of pet goldfish (Carassius auratus), reference intervals have not been generated for routine biochemistry panel analytes in this species. This study establishes de novo reference intervals for packed cell volume and total solids, using 47 apparently healthy immature goldfish, and for 11 common chemistry panel analytes (albumin, aspartate aminotransferase, calcium, creatine kinase, globulin, blood glucose, sodium, potassium, phosphorous, total protein, and uric acid) using 39 immature goldfish. Robust reference intervals were generated following recommendations of the American Society for Veterinary Clinical Pathology. Linear regression was used to demonstrate a statistically significant relationship between body weight and calcium, albumin, total protein, potassium, packed cell volume, and total solids. The results of this study serve as a useful baseline for future reference interval generation in goldfish.

  15. The game of Double-Silver on intervals

    Directory of Open Access Journals (Sweden)

    Gerald A. Heuer

    2001-01-01

    Full Text Available Silverman's game on intervals was analyzed in a special case by Evans, and later more extensively by Heuer and Leopold-Wildburger, who found that optimal strategies exist (and gave them quite generally when the intervals have no endpoints in common. They exist in about half the parameter plane when the intervals have a left endpoint or a right endpoint, but not both, in common, and (as Evans had earlier found exist only on a set of measure zero in this plane if the intervals are identical. The game of Double-Silver, where each player has its own threshold and penalty, is examined. There are several combinations of conditions on relative placement of the intervals, the thresholds and penalties under which optimal strategies exist and are found. The indications are that in the other cases no optimal strategies exist.

  16. Quantitative Assessment of the Physiological Parameters Influencing QT Interval Response to Medication: Application of Computational Intelligence Tools.

    Science.gov (United States)

    Polak, Sebastian; Wiśniowska, Barbara; Mendyk, Aleksander; Pacławski, Adam; Szlęk, Jakub

    2018-01-01

    Human heart electrophysiology is complex biological phenomenon, which is indirectly assessed by the measured ECG signal. ECG trace is further analyzed to derive interpretable surrogates including QT interval, QRS complex, PR interval, and T wave morphology. QT interval and its modification are the most commonly used surrogates of the drug triggered arrhythmia, but it is known that the QT interval itself is determined by other nondrug related parameters, physiological and pathological. In the current study, we used the computational intelligence algorithms to analyze correlations between various simulated physiological parameters and QT interval. Terfenadine given concomitantly with 8 enzymatic inhibitors was used as an example. The equation developed with the use of genetic programming technique leads to general reasoning about the changes in the prolonged QT. For small changes of the QT interval, the drug-related IKr and ICa currents inhibition potentials have major impact. The physiological parameters such as body surface area, potassium, sodium, and calcium ions concentrations are negligible. The influence of the physiological variables increases gradually with the more pronounced changes in QT. As the significant QT prolongation is associated with the drugs triggered arrhythmia risk, analysis of the role of physiological parameters influencing ECG seems to be advisable.

  17. TV Inhibiting Creative Ideas

    Science.gov (United States)

    Intellect, 1977

    1977-01-01

    Television may be inhibiting our ability to create new ideas, according to Eric Somers, assistant professor of journalism at Drake University. Discusses television's role as facilitator of information and how it should improve to increase organization and the creative process. (Editor/RK)

  18. Enzyme inhibition by iminosugars

    DEFF Research Database (Denmark)

    López, Óscar; Qing, Feng-Ling; Pedersen, Christian Marcus

    2013-01-01

    Imino- and azasugar glycosidase inhibitors display pH dependant inhibition reflecting that both the inhibitor and the enzyme active site have groups that change protonation state with pH. With the enzyme having two acidic groups and the inhibitor one basic group, enzyme-inhibitor complexes...

  19. Predicting fecal coliform using the interval-to-interval approach and SWAT in the Miyun watershed, China.

    Science.gov (United States)

    Bai, Jianwen; Shen, Zhenyao; Yan, Tiezhu; Qiu, Jiali; Li, Yangyang

    2017-06-01

    Pathogens in manure can cause waterborne-disease outbreaks, serious illness, and even death in humans. Therefore, information about the transformation and transport of bacteria is crucial for determining their source. In this study, the Soil and Water Assessment Tool (SWAT) was applied to simulate fecal coliform bacteria load in the Miyun Reservoir watershed, China. The data for the fecal coliform were obtained at three sampling sites, Chenying (CY), Gubeikou (GBK), and Xiahui (XH). The calibration processes of the fecal coliform were conducted using the CY and GBK sites, and validation was conducted at the XH site. An interval-to-interval approach was designed and incorporated into the processes of fecal coliform calibration and validation. The 95% confidence interval of the predicted values and the 95% confidence interval of measured values were considered during calibration and validation in the interval-to-interval approach. Compared with the traditional point-to-point comparison, this method can improve simulation accuracy. The results indicated that the simulation of fecal coliform using the interval-to-interval approach was reasonable for the watershed. This method could provide a new research direction for future model calibration and validation studies.

  20. The proximate determinants of fertility and birth intervals in Egypt: An application of calendar data

    Directory of Open Access Journals (Sweden)

    Andrew Hinde

    2007-01-01

    Full Text Available In this paper we use calendar data from the 2000 Egyptian Demographic and Health Survey (DHS to assess the determinants of birth interval length among women who are in union. We make use of the well-known model of the proximate determinants of fertility, and take advantage of the fact that the DHS calendar data provide month-by-month data on contraceptive use, breastfeeding and post-partum amenorrhoea, which are the most important proximate determinants among women in union. One aim of the analysis is to see whether the calendar data are sufficiently detailed to account for all variation among individual women in birth interval duration, in that once they are controlled, the effect of background social, economic and cultural variables is not statistically significant. The results suggest that this is indeed the case, especially after a random effect term to account for the unobserved proximate determinants is included in the model. Birth intervals are determined mainly by the use of modern methods of contraception (the IUD being more effective than the pill. Breastfeeding and post-partum amenorrhoea both inhibit conception, and the effect of breastfeeding remains even after the period of amenorrhoea has ended.

  1. NHSBSP type 1 interval cancers: a scientifically valid grouping?

    International Nuclear Information System (INIS)

    Porter, G.J.R.; Evans, A.J.; Burrell, H.C.; Lee, A.H.S.; Chakrabarti, J.

    2007-01-01

    Aim: To assess whether there are differences in the pathological features or survival between the new National Health Service Breast Screening Programme (NHSBSP) interval cancer classification system category of type 1 interval cancers, and the previously used, separate categories of occult, unclassified, and true interval cancers. Materials and methods: The prognostic pathological features (grade, lymph node stage, size, vascular invasion, oestrogen receptor status, and histological type) and survival of 428 type 1 interval invasive breast cancers were analysed by subgroup (occult, unclassified and true interval). Results: Occult cancers compared with other type 1 interval cancers were of significantly lower grade [38 of 52 (73%) versus 151 of 340 (44%) grade 1 or 2, p = 0.0005], more likely to be smaller size [37 of 51 (73%) versus 158 of 341 (46%) <20 mm, p = 0.0003] and more frequently of lobular type at histology [14 of 42 (32%) versus 50 of 286 (17%), p = 0.03]. There was no significant difference in pathological features of unclassified tumours compared with other type 1 tumours. There was no significant survival difference between different type 1 subgroups (p = 0.12). Conclusion: The NHSBSP type 1 interval cancers are a heterogeneous grouping with markedly differing pathological features. However, no significant survival difference is seen between the different type 1 subgroups

  2. NHSBSP type 1 interval cancers: a scientifically valid grouping?

    Energy Technology Data Exchange (ETDEWEB)

    Porter, G.J.R. [Nottingham Breast Institute, City Hospital, Nottingham (United Kingdom)]. E-mail: garethporter@doctors.org.uk; Evans, A.J. [Nottingham Breast Institute, City Hospital, Nottingham (United Kingdom); Burrell, H.C. [Nottingham Breast Institute, City Hospital, Nottingham (United Kingdom); Lee, A.H.S. [Nottingham Breast Institute, City Hospital, Nottingham (United Kingdom); Chakrabarti, J. [Nottingham Breast Institute, City Hospital, Nottingham (United Kingdom)

    2007-03-15

    Aim: To assess whether there are differences in the pathological features or survival between the new National Health Service Breast Screening Programme (NHSBSP) interval cancer classification system category of type 1 interval cancers, and the previously used, separate categories of occult, unclassified, and true interval cancers. Materials and methods: The prognostic pathological features (grade, lymph node stage, size, vascular invasion, oestrogen receptor status, and histological type) and survival of 428 type 1 interval invasive breast cancers were analysed by subgroup (occult, unclassified and true interval). Results: Occult cancers compared with other type 1 interval cancers were of significantly lower grade [38 of 52 (73%) versus 151 of 340 (44%) grade 1 or 2, p = 0.0005], more likely to be smaller size [37 of 51 (73%) versus 158 of 341 (46%) <20 mm, p = 0.0003] and more frequently of lobular type at histology [14 of 42 (32%) versus 50 of 286 (17%), p = 0.03]. There was no significant difference in pathological features of unclassified tumours compared with other type 1 tumours. There was no significant survival difference between different type 1 subgroups (p = 0.12). Conclusion: The NHSBSP type 1 interval cancers are a heterogeneous grouping with markedly differing pathological features. However, no significant survival difference is seen between the different type 1 subgroups.

  3. Hematological Reference Intervals for Healthy Iranian Blood Donors.

    Science.gov (United States)

    Rasouli, Mahboubeh; Pourmokhtar, Mojgan; Sarkardeh, Shaghayegh

    2017-10-01

    Background: Development of locally-derived hematological reference intervals is necessary for improving the quality of health care and clinical trials. However hematological reference intervals are affected by several variables including age, gender and environmental factors. Therefore this study was conducted to determine the gender and age-specific hematological reference intervals of healthy Iranian blood donors. Materials and Methods: Selected hematological indices of 394 healthy blood donor volunteers, donating blood at Tehran Blood Transfusion Center were analyzed. Hematological reference intervals, stratified by age and gender were compared. The results of current study were also compared with those of US population. Results: There were significant gender-related differences for mean values of hematological indices, with males having higher mean values of RBC, HCG, HCT and MCV than females. While the mean of PLT and MCH were higher in women. Age-related differences for mean values of RBC and MCH were also significant. The comparison of reference intervals, stratified by both gender and age showed that RBC, HGB and HCT values were higher in males than females in all age groups. But MCH values of females in all age groups and WBC and PLT counts in females older than 30 years were higher compared to the males in the same age group. The results of this study showed some similarity with US population, with narrower intervals. Conclusion: This study suggests that gender and age-specific, locally derived hematological reference intervals should be referred to, before interpretation of any laboratory test result.

  4. Complete blood count reference intervals for healthy Han Chinese adults.

    Directory of Open Access Journals (Sweden)

    Xinzhong Wu

    Full Text Available Complete blood count (CBC reference intervals are important to diagnose diseases, screen blood donors, and assess overall health. However, current reference intervals established by older instruments and technologies and those from American and European populations are not suitable for Chinese samples due to ethnic, dietary, and lifestyle differences. The aim of this multicenter collaborative study was to establish CBC reference intervals for healthy Han Chinese adults.A total of 4,642 healthy individuals (2,136 males and 2,506 females were recruited from six clinical centers in China (Shenyang, Beijing, Shanghai, Guangzhou, Chengdu, and Xi'an. Blood samples collected in K2EDTA anticoagulant tubes were analyzed. Analysis of variance was performed to determine differences in consensus intervals according to the use of data from the combined sample and selected samples.Median and mean platelet counts from the Chengdu center were significantly lower than those from other centers. Red blood cell count (RBC, hemoglobin (HGB, and hematocrit (HCT values were higher in males than in females at all ages. Other CBC parameters showed no significant instrument-, region-, age-, or sex-dependent difference. Thalassemia carriers were found to affect the lower or upper limit of different RBC profiles.We were able to establish consensus intervals for CBC parameters in healthy Han Chinese adults. RBC, HGB, and HCT intervals were established for each sex. The reference interval for platelets for the Chengdu center should be established independently.

  5. Complete Blood Count Reference Intervals for Healthy Han Chinese Adults

    Science.gov (United States)

    Mu, Runqing; Guo, Wei; Qiao, Rui; Chen, Wenxiang; Jiang, Hong; Ma, Yueyun; Shang, Hong

    2015-01-01

    Background Complete blood count (CBC) reference intervals are important to diagnose diseases, screen blood donors, and assess overall health. However, current reference intervals established by older instruments and technologies and those from American and European populations are not suitable for Chinese samples due to ethnic, dietary, and lifestyle differences. The aim of this multicenter collaborative study was to establish CBC reference intervals for healthy Han Chinese adults. Methods A total of 4,642 healthy individuals (2,136 males and 2,506 females) were recruited from six clinical centers in China (Shenyang, Beijing, Shanghai, Guangzhou, Chengdu, and Xi’an). Blood samples collected in K2EDTA anticoagulant tubes were analyzed. Analysis of variance was performed to determine differences in consensus intervals according to the use of data from the combined sample and selected samples. Results Median and mean platelet counts from the Chengdu center were significantly lower than those from other centers. Red blood cell count (RBC), hemoglobin (HGB), and hematocrit (HCT) values were higher in males than in females at all ages. Other CBC parameters showed no significant instrument-, region-, age-, or sex-dependent difference. Thalassemia carriers were found to affect the lower or upper limit of different RBC profiles. Conclusion We were able to establish consensus intervals for CBC parameters in healthy Han Chinese adults. RBC, HGB, and HCT intervals were established for each sex. The reference interval for platelets for the Chengdu center should be established independently. PMID:25769040

  6. The association between atrium electromechanical interval and pericardial fat.

    Directory of Open Access Journals (Sweden)

    Tze-Fan Chao

    Full Text Available OBJECTIVES: Pericardial fat (PCF may induce local inflammation and subsequent structural remodeling of the left atrium (LA. However, the adverse effects of PCF on LA are difficult to be evaluated and quantified. The atrial electromechanical interval determined by transthoracic echocardiogram was shown to be a convenient parameter which can reflect the process of LA remodeling. The goal of the present study was to investigate the association between the electromechanical interval and PCF. METHODS AND RESULTS: A total of 337 patients with mean age of 51.9 ± 9.0 years were enrolled. The electromechanical interval (PA-PDI defined as the time interval from the initiation of the P wave deflection to the peak of the mitral inflow A wave on the pulse wave Doppler imaging was measured for every patient. The amount of PCF was determined by multi-detector computed tomography. The PA-PDI interval was significantly correlated with the amount of PCF (r = 0.641, p value <0.001. Graded prolongation of PA-PDI interval was observed across 3 groups of patients divided according to the tertile values of PCF. The AUC for the PA-PDI interval in predicting an increased amount of PCF (third tertile was 0.796. At a cutoff value of 130 ms identified by the ROC curve, the sensitivity and specificity of PA-PDI interval in identifying patients with a highest tertile of PCF were 63.4% and 85.3%, respectively. CONCLUSIONS: The PA-PDI intervals were longer in patients with an increased amount of PCF. It may be a useful parameter to represent the degree of PCF-related atrial remodeling.

  7. The Role of Higher Harmonics In Musical Interval Perception

    Science.gov (United States)

    Krantz, Richard; Douthett, Jack

    2011-10-01

    Using an alternative parameterization of the roughness curve we make direct use of critical band results to investigate the role of higher harmonics on the perception of tonal consonance. We scale the spectral amplitudes in the complex home tone and complex interval tone to simulate acoustic signals of constant energy. Our analysis reveals that even with a relatively small addition of higher harmonics the perfect fifth emerges as a consonant interval with more, musically important, just intervals emerging as consonant as more and more energy is shifted into higher frequencies.

  8. MRI of the rotator interval of the shoulder

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J.C. [Department of Radiology, Royal National Orthopaedic Hospital NHS Trust, Stanmore, Middlesex (United Kingdom); Guy, S. [Department of Radiology, Royal National Orthopaedic Hospital NHS Trust, Stanmore, Middlesex (United Kingdom); Connell, D. [Department of Radiology, Royal National Orthopaedic Hospital NHS Trust, Stanmore, Middlesex (United Kingdom); Saifuddin, A. [Department of Radiology, Royal National Orthopaedic Hospital NHS Trust, Stanmore, Middlesex (United Kingdom) and Institute of Orthopaedics and Musculoskeletal Sciences, University College London (United Kingdom)]. E-mail: asaifuddin@aol.com; Lambert, S. [Department of Orthopaedics, Royal National Orthopaedic Hospital NHS Trust, Stanmore, Middlesex (United Kingdom); Institute of Orthopaedics and Musculoskeletal Sciences, University College London (United Kingdom)

    2007-05-15

    The rotator interval of the shoulder joint is located between the distal edges of the supraspinatus and subscapularis tendons and contains the insertions of the coracohumeral and superior glenohumeral ligaments. These structures form a complex pulley system that stabilizes the long head of the biceps tendon as it enters the bicipital groove of the humeral head. The rotator interval is the site of a variety of pathological processes including biceps tendon lesions, adhesive capsulitis and anterosuperior internal impingement. This article describes the anatomy, function and pathology of the rotator interval using magnetic resonance imaging (MRI)

  9. Estimation of individual reference intervals in small sample sizes

    DEFF Research Database (Denmark)

    Hansen, Ase Marie; Garde, Anne Helene; Eller, Nanna Hurwitz

    2007-01-01

    of that order of magnitude for all topics in question. Therefore, new methods to estimate reference intervals for small sample sizes are needed. We present an alternative method based on variance component models. The models are based on data from 37 men and 84 women taking into account biological variation...... presented in this study. The presented method enables occupational health researchers to calculate reference intervals for specific groups, i.e. smokers versus non-smokers, etc. In conclusion, the variance component models provide an appropriate tool to estimate reference intervals based on small sample...

  10. Concept of Operations for Interval Management Arrivals and Approach

    Science.gov (United States)

    Hicok, Daniel S.; Barmore, Bryan E.

    2016-01-01

    This paper presents the concept of operations for interval management operations to be deployed in the US National Airspace System (NAS) by the Federal Aviation Administration (FAA) after 2020. The use of interval management operations is described that begin in en route airspace and continue to a termination point inside the arrival terminal area, in a terminal environment that includes other arrival management tools such as arrival metering, Ground-based Interval Management - Spacing (GIM-S), and Terminal Sequencing and Spacing (TSAS). The roles of Air Traffic Controllers and Flight Crews and the ground automation tools that are used by Air Traffic Controllers to enable the primary operation and variations are described.

  11. Optimizing calibration intervals for specific applications to reduce maintenance costs

    Energy Technology Data Exchange (ETDEWEB)

    Collier, Steve; Holland, Jack [Servomex Group, Crowborough (United Kingdom)

    2009-11-01

    The introduction of the Servomex MultiExact 5400 analyzer has presented an opportunity to review the cost of ownership and how improvements to an analyzer's performance may be used to reduce this. Until now, gas analyzer manufacturers have taken a conservative approach to calibration intervals based on site practices and experience covering a wide range of applications. However, if specific applications are considered, then there is an opportunity to reduce costs by increasing calibration intervals. This paper demonstrates how maintenance costs may be reduced by increasing calibration intervals for those gas analyzers used for monitoring Air Separation Units (ASUs) without detracting from their performance.(author)

  12. Time interval approach to the pulsed neutron logging method

    International Nuclear Information System (INIS)

    Zhao Jingwu; Su Weining

    1994-01-01

    The time interval of neighbouring neutrons emitted from a steady state neutron source can be treated as that from a time-dependent neutron source. In the rock space, the neutron flux is given by the neutron diffusion equation and is composed of an infinite terms. Each term s composed of two die-away curves. The delay action is discussed and used to measure the time interval with only one detector in the experiment. Nuclear reactions with the time distribution due to different types of radiations observed in the neutron well-logging methods are presented with a view to getting the rock nuclear parameters from the time interval technique

  13. Inhibition of synaptically evoked cortical acetylcholine release by adenosine: an in vivo microdialysis study in the rat.

    Science.gov (United States)

    Materi, L M; Rasmusson, D D; Semba, K

    2000-01-01

    The release of cortical acetylcholine from the intracortical axonal terminals of cholinergic basal forebrain neurons is closely associated with electroencephalographic activity. One factor which may act to reduce cortical acetylcholine release and promote sleep is adenosine. Using in vivo microdialysis, we examined the effect of adenosine and selective adenosine receptor agonists and antagonists on cortical acetylcholine release evoked by electrical stimulation of the pedunculopontine tegmental nucleus in urethane anesthetized rats. All drugs were administered locally within the cortex by reverse dialysis. None of the drugs tested altered basal release of acetylcholine in the cortex. Adenosine significantly reduced evoked cortical acetylcholine efflux in a concentration-dependent manner. This was mimicked by the adenosine A(1) receptor selective agonist N(6)-cyclopentyladenosine and blocked by the selective A(1) receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX). The A(2A) receptor agonist 2-[p-(2-carboxyethyl)-phenethylamino]-5'-N-ethylcarboxamidoadenosi ne hydrochloride (CGS 21680) did not alter evoked cortical acetylcholine release even in the presence of DPCPX. Administered alone, neither DPCPX nor the non-selective adenosine receptor antagonist caffeine affected evoked cortical acetylcholine efflux. Simultaneous delivery of the adenosine uptake inhibitors dipyridamole and S-(4-nitrobenzyl)-6-thioinosine significantly reduced evoked cortical acetylcholine release, and this effect was blocked by the simultaneous administration of caffeine. These data indicate that activation of the A(1) adenosine receptor inhibits acetylcholine release in the cortex in vivo while the A(2A) receptor does not influence acetylcholine efflux. Such inhibition of cortical acetylcholine release by adenosine may contribute to an increased propensity to sleep during prolonged wakefulness.

  14. Inhibiting the inevitable

    DEFF Research Database (Denmark)

    Shashoua, Yvonne

    2006-01-01

    conservation is to ‘buy time’ for the object. Inhibitive conservation of plastics involves the removal or reduction of factors causing or accelerating degradation including light, oxygen, acids, relative humidity and acidic breakdown products. Specific approaches to conservation have been developed......Once plastics objects are registered in museum collections, the institution becomes responsible for their long term preservation, until the end of their useful lifetime. Plastics appear to deteriorate faster than other materials in museum collections and have a useful lifetime between 5 and 25...... years. Preventive or inhibitive conservation involves controlling the environments in which objects are placed during storage and display, with the aim of slowing the major deterioration reactions. Once in progress, degradation of plastics cannot be stopped or reversed, so the aim of preventive...

  15. Plastics for corrosion inhibition

    CERN Document Server

    Goldade, Victor A; Makarevich, Anna V; Kestelman, Vladimir N

    2005-01-01

    The development of polymer composites containing inhibitors of metal corrosion is an important endeavour in modern materials science and technology. Corrosion inhibitors can be located in a polymer matrix in the solid, liquid or gaseous phase. This book details the thermodynamic principles for selecting these components, their compatibility and their effectiveness. The various mechanisms of metal protection – barrier, inhibiting and electromechanical – are considered, as are the conflicting requirements placed on the structure of the combined material. Two main classes of inhibited materials (structural and films/coatings) are described in detail. Examples are given of structural plastics used in friction units subjected to mechano-chemical wear and of polymer films/coatings for protecting metal objects against corrosion.

  16. On interval methods applied to robot reliability quantification

    International Nuclear Information System (INIS)

    Carreras, C.; Walker, I.D.

    2000-01-01

    Interval methods have recently been successfully applied to obtain significantly improved robot reliability estimates via fault trees for the case of uncertain and time-varying input reliability data. These initial studies generated output distributions of failure probabilities by extending standard interval arithmetic with new abstractions called interval grids which can be parameterized to control the complexity and accuracy of the estimation process. In this paper different parameterization strategies are evaluated in order to gain a more complete understanding of the potential benefits of the approach. A canonical example of a robot manipulator system is used to show that an appropriate selection of parameters is a key issue for the successful application of such novel interval-based methodologies

  17. A Statistical Approach for Interval Forecasting of the Electricity Price

    DEFF Research Database (Denmark)

    Zhao, Jun Hua; Dong, Zhao Yang; Xu, Zhao

    2008-01-01

    Electricity price forecasting is a difficult yet essential task for market participants in a deregulated electricity market. Rather than forecasting the value, market participants are sometimes more interested in forecasting the prediction interval of the electricity price. Forecasting...... the prediction interval is essential for estimating the uncertainty involved in the price and thus is highly useful for making generation bidding strategies and investment decisions. In this paper, a novel data mining-based approach is proposed to achieve two major objectives: 1) to accurately forecast the value...... of the electricity price series, which is widely accepted as a nonlinear time series; 2) to accurately estimate the prediction interval of the electricity price series. In the proposed approach, support vector machine (SVM) is employed to forecast the value of the price. To forecast the prediction interval, we...

  18. From special relativity to quantum mechanics through interval

    International Nuclear Information System (INIS)

    Malcor, R.

    1985-01-01

    Quantum mechanics is an optics with one more spatial dimension, the angle of phase. Wave-particle duality is nothing else than geometric tangent-point duality. The 'interval' of special relativity is proportional to the phase

  19. Discrete-time optimal control and games on large intervals

    CERN Document Server

    Zaslavski, Alexander J

    2017-01-01

    Devoted to the structure of approximate solutions of discrete-time optimal control problems and approximate solutions of dynamic discrete-time two-player zero-sum games, this book presents results on properties of approximate solutions in an interval that is independent lengthwise, for all sufficiently large intervals. Results concerning the so-called turnpike property of optimal control problems and zero-sum games in the regions close to the endpoints of the time intervals are the main focus of this book. The description of the structure of approximate solutions on sufficiently large intervals and its stability will interest graduate students and mathematicians in optimal control and game theory, engineering, and economics. This book begins with a brief overview and moves on to analyze the structure of approximate solutions of autonomous nonconcave discrete-time optimal control Lagrange problems.Next the structures of approximate solutions of autonomous discrete-time optimal control problems that are discret...

  20. Spectral of electrocardiographic RR intervals to indicate atrial fibrillation

    Science.gov (United States)

    Nuryani, Nuryani; Satrio Nugroho, Anto

    2017-11-01

    Atrial fibrillation is a serious heart diseases, which is associated on the risk of death, and thus an early detection of atrial fibrillation is necessary. We have investigated spectral pattern of electrocardiogram in relation to atrial fibrillation. The utilized feature of electrocardiogram is RR interval. RR interval is the time interval between a two-consecutive R peaks. A series of RR intervals in a time segment is converted to a signal with a frequency domain. The frequency components are investigated to find the components which significantly associate to atrial fibrillation. A segment is defined as atrial fibrillation or normal segments by considering a defined number of atrial fibrillation RR in the segment. Using clinical data of 23 patients with atrial fibrillation, we find that the frequency components could be used to indicate atrial fibrillation.

  1. Recommended Nordic paediatric reference intervals for 21 common biochemical properties

    DEFF Research Database (Denmark)

    Hilsted, Linda; Rustad, Pål; Aksglæde, Lise

    2013-01-01

    Abstract Paediatric reference intervals based on samples from healthy children are difficult to establish and consequently data are often from hospitalized children. Furthermore, biases may present in published data due to differences in the analytical methods employed. Blood samples from 1429...... healthy Danish children were collected for establishing reference intervals for 21 common biochemical properties (Alanine transaminase, Albumin, Alkaline phosphatase, Aspartate transaminase, Bilirubin, Calcium, Cholesterol, Creatinine, Creatine kinase, HDL-Cholesterol, Iron, Lactate dehydrogenase, LDL...... values of X for the properties and statistical calculations carried out as performed in the NORIP study. Thus commutable (regarding analytical method) reference intervals for 20 properties were established and for LDL-Cholesterol reference intervals were reported for the specific analytical method...

  2. Symbol interval optimization for molecular communication with drift.

    Science.gov (United States)

    Kim, Na-Rae; Eckford, Andrew W; Chae, Chan-Byoung

    2014-09-01

    In this paper, we propose a symbol interval optimization algorithm in molecular communication with drift. Proper symbol intervals are important in practical communication systems since information needs to be sent as fast as possible with low error rates. There is a trade-off, however, between symbol intervals and inter-symbol interference (ISI) from Brownian motion. Thus, we find proper symbol interval values considering the ISI inside two kinds of blood vessels, and also suggest no ISI system for strong drift models. Finally, an isomer-based molecule shift keying (IMoSK) is applied to calculate achievable data transmission rates (achievable rates, hereafter). Normalized achievable rates are also obtained and compared in one-symbol ISI and no ISI systems.

  3. Symbol lock detection implemented with nonoverlapping integration intervals

    Science.gov (United States)

    Shihabi, Mazen M. (Inventor); Hinedi, Sami M. (Inventor); Shah, Biren N. (Inventor)

    1995-01-01

    A symbol lock detector is introduced for an incoming coherent digital communication signal which utilizes a subcarrier modulated with binary symbol data, d(sub k), and known symbol interval T by integrating binary values of the signal over nonoverlapping first and second intervals selected to be T/2, delaying the first integral an interval T/2, and either summing or multiplying the second integral with the first one that preceded it to form a value X(sub k). That value is then averaged over a number M of symbol intervals to produce a static value Y. A symbol lock decision can then be made when the static value Y exceeds a threshold level delta.

  4. Experimental uncertainty estimation and statistics for data having interval uncertainty.

    Energy Technology Data Exchange (ETDEWEB)

    Kreinovich, Vladik (Applied Biomathematics, Setauket, New York); Oberkampf, William Louis (Applied Biomathematics, Setauket, New York); Ginzburg, Lev (Applied Biomathematics, Setauket, New York); Ferson, Scott (Applied Biomathematics, Setauket, New York); Hajagos, Janos (Applied Biomathematics, Setauket, New York)

    2007-05-01

    This report addresses the characterization of measurements that include epistemic uncertainties in the form of intervals. It reviews the application of basic descriptive statistics to data sets which contain intervals rather than exclusively point estimates. It describes algorithms to compute various means, the median and other percentiles, variance, interquartile range, moments, confidence limits, and other important statistics and summarizes the computability of these statistics as a function of sample size and characteristics of the intervals in the data (degree of overlap, size and regularity of widths, etc.). It also reviews the prospects for analyzing such data sets with the methods of inferential statistics such as outlier detection and regressions. The report explores the tradeoff between measurement precision and sample size in statistical results that are sensitive to both. It also argues that an approach based on interval statistics could be a reasonable alternative to current standard methods for evaluating, expressing and propagating measurement uncertainties.

  5. A study of intensity, fatigue and precision in two specific interval trainings in young tennis players: high-intensity interval training versus intermittent interval training.

    Science.gov (United States)

    Suárez Rodríguez, David; Del Valle Soto, Miguel

    2017-01-01

    The aim of this study is to find the differences between two specific interval exercises. We begin with the hypothesis that the use of microintervals of work and rest allow for greater intensity of play and a reduction in fatigue. Thirteen competition-level male tennis players took part in two interval training exercises comprising nine 2 min series, which consisted of hitting the ball with cross-court forehand and backhand shots, behind the service box. One was a high-intensity interval training (HIIT), made up of periods of continuous work lasting 2 min, and the other was intermittent interval training (IIT), this time with intermittent 2 min intervals, alternating periods of work with rest periods. Average heart rate (HR) and lactate levels were registered in order to observe the physiological intensity of the two exercises, along with the Borg Scale results for perceived exertion and the number of shots and errors in order to determine the intensity achieved and the degree of fatigue throughout the exercise. There were no significant differences in the average heart rate, lactate or the Borg Scale. Significant differences were registered, on the other hand, with a greater number of shots in the first two HIIT series (series 1 p>0.009; series 2 p>0.056), but not in the third. The number of errors was significantly lower in all the IIT series (series 1 ptraining allows for greater intensity of play in relation to the real time spent on the exercise, reduced fatigue levels and the maintaining of greater precision in specific tennis-related exercises.

  6. Hybrid Metric Propositional Neighborhood Logics with Interval Length Binders

    DEFF Research Database (Denmark)

    Della Monica, Dario; Goranko, Valentin; Sciavicco, Guido

    2011-01-01

    We investigate the question of how much hybrid machinery can be added to the interval neighbourhood logic PNL and its metric extension MPNL without losing the decidability of their satisfiability problem in N. In particular, we consider the natural hybrid extension of MPNL obtained by adding...... over interval lengths. These results show that MPNL itself is, in this sense, a maximal decidable (weakly) hybrid extension of PNL. © 2011 Elsevier B.V. All rights reserved....

  7. Ion–Cyclotron Resonance Frequency Interval Dependence on the O ...

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... The frequency intervals in which O VI ions get in resonance with ion–cyclotron waves are calculated using the kinetic model, for the latest six values found in literature on O VI ion number densities in the 1.5–3 region of the NPCH. It is found that the common resonance interval is 1.5 kHz to 3 kHz.

  8. Clinical laboratory reference intervals in pediatrics: the CALIPER initiative.

    Science.gov (United States)

    Jung, Benjamin; Adeli, Khosrow

    2009-11-01

    Reference intervals provided on laboratory reports are essential for appropriate interpretation of test results, and can significantly impact clinical decision-making and the quality of patient care. Careful determination and/or validation of reference intervals by the laboratory for use in the patient population it serves are therefore important to ensure their proper utility. Unfortunately, critical gaps currently exist in accurate and up-to-date pediatric reference intervals for accurate interpretation of laboratory tests performed in children and adolescents. These critical gaps in the available pediatric laboratory reference intervals have the clear potential of contributing to erroneous diagnosis or misdiagnosis of many diseases of childhood and adolescence. Most of the available "normal" ranges for laboratory tests were determined over 2 decades ago on older instruments and technologies, and are no longer relevant considering the current testing technology used by clinical laboratories. It is thus critical and of utmost urgency that a more acceptable and comprehensive database be established. In the present review, we discuss the considerations and challenges faced when generating and validating reference intervals in accordance to the current guidelines published by the Clinical Laboratory Standards Institute (CLSI). We raise particular attention to the present-day deficiencies in available pediatric reference intervals, and highlight the special issues and unique difficulties that are additionally faced when establishing reference intervals in children. Finally, we highlight a recent Canadian initiative, the CALIPER project, whose mandate is to establish and maintain a database of comprehensive and up-to-date pediatric reference intervals to be eventually made available to all clinical laboratories worldwide.

  9. Military Applicability of Interval Training for Health and Performance.

    Science.gov (United States)

    Gibala, Martin J; Gagnon, Patrick J; Nindl, Bradley C

    2015-11-01

    Militaries from around the globe have predominantly used endurance training as their primary mode of aerobic physical conditioning, with historical emphasis placed on the long distance run. In contrast to this traditional exercise approach to training, interval training is characterized by brief, intermittent bouts of intense exercise, separated by periods of lower intensity exercise or rest for recovery. Although hardly a novel concept, research over the past decade has shed new light on the potency of interval training to elicit physiological adaptations in a time-efficient manner. This work has largely focused on the benefits of low-volume interval training, which involves a relatively small total amount of exercise, as compared with the traditional high-volume approach to training historically favored by militaries. Studies that have directly compared interval and moderate-intensity continuous training have shown similar improvements in cardiorespiratory fitness and the capacity for aerobic energy metabolism, despite large differences in total exercise and training time commitment. Interval training can also be applied in a calisthenics manner to improve cardiorespiratory fitness and strength, and this approach could easily be incorporated into a military conditioning environment. Although interval training can elicit physiological changes in men and women, the potential for sex-specific adaptations in the adaptive response to interval training warrants further investigation. Additional work is needed to clarify adaptations occurring over the longer term; however, interval training deserves consideration from a military applicability standpoint as a time-efficient training strategy to enhance soldier health and performance. There is value for military leaders in identifying strategies that reduce the time required for exercise, but nonetheless provide an effective training stimulus.

  10. Establishment of reference intervals and transfusion criterion for Sonoclot analysis.

    Science.gov (United States)

    Zhang, Zhen-Lu; Chen, You-Ping; Tao, Cui-Hua; Liu, Xiao-Hui; Li, Meng-Ya; Zhou, Xin

    2016-08-01

    Sonoclot analyzer has been widely used in many countries. But the reference intervals provided by the manufacturer were derived from only 45 participants, and there was no cut-off value for transfusion for Sonoclot analysis. This study aimed to establish reference intervals and transfusion criterion for Sonoclot analysis. Volunteers were recruited from healthy Chinese adults and patients undergoing cardiac surgery. Blood samples were withdrawn from forearm vein and measured for activated clotting time (ACT), clot rate (CR), platelet function (PF), activated partial thromboplastin time (APTT), fibrinogen concentration (FIB), and platelet count (PLT). The reference intervals were determined by the nonparametric method. Cut-off values were determined by the receiver operating characteristics curve. A total of 135 healthy volunteers and 281 patients were enrolled. The 95% reference intervals were 96-195 s, 22-51 signal U/min, >1.6 for ACT, CR, PF respectively. In the 281 patients, the results of APTT, FIB, PLT, ACT, CR, and PF ranged from 20.5-300.0 s, 0.28-4.11 g/L, (19.0-387.3)×109/L, 80-514 s, 2.9-74 signal U/min, and 0.1-5.1 respectively. The cut-off values for transfusion were >208, ≤14, and ≤1.3 for ACT, CR, PF respectively. The cut-off values of Sonoclot analysis were within the manufacturer's reference intervals, while they were outside the reference intervals established in this study. The results suggested that the manufacturer's reference intervals were not suitable for Chinese. The reference intervals and cut-off values established in this study will be helpful to Chinese patients.

  11. Bone turnover marker reference intervals in young females.

    Science.gov (United States)

    Callegari, Emma T; Gorelik, Alexandra; Garland, Suzanne M; Chiang, Cherie Y; Wark, John D

    2017-07-01

    Background The use of bone turnover markers in clinical practice and research in younger people is limited by the lack of normative data and understanding of common causes of variation in bone turnover marker values in this demographic. To appropriately interpret bone turnover markers, robust reference intervals specific to age, development and sex are necessary. This study aimed to determine reference intervals of bone turnover markers in females aged 16-25 years participating in the Safe-D study. Methods Participants were recruited through social networking site Facebook and were asked to complete an extensive, online questionnaire and attend a site visit. Participants were tested for serum carboxy-terminal cross-linking telopeptide of type 1 collagen and total procollagen type 1 N-propeptide using the Roche Elecsys automated analyser. Reference intervals were determined using the 2.5th to 97.5th percentiles of normalized bone turnover marker values. Results Of 406 participants, 149 were excluded due to medical conditions or medication use (except hormonal contraception) which may affect bone metabolism. In the remaining 257 participants, the reference interval was 230-1000 ng/L for serum carboxy-terminal cross-linking telopeptide of type 1 collagen and 27-131  µg/L for procollagen type 1 N-propeptide. Both marker concentrations were inversely correlated with age and oral contraceptive pill use. Therefore, intervals specific to these variables were calculated. Conclusions We defined robust reference intervals for cross-linking telopeptide of type 1 collagen and procollagen type 1 N-propeptide in young females grouped by age and contraceptive pill use. We examined bone turnover markers' relationship with several lifestyle, clinical and demographic factors. Our normative intervals should aid interpretation of bone turnover markers in young females particularly in those aged 16 to 19 years where reference intervals are currently provisional.

  12. Ion–Cyclotron Resonance Frequency Interval Dependence on the O ...

    Indian Academy of Sciences (India)

    The frequency intervals in which O VI ions get in resonance with ion–cyclotron waves are calculated using the kinetic model, for the latest six values found in literature on O VI ion number densities in the 1.5–3 region of the NPCH. It is found that the common resonance interval is 1.5 kHz to 3 kHz. The -variations of wave ...

  13. A Neural Network-Based Interval Pattern Matcher

    Directory of Open Access Journals (Sweden)

    Jing Lu

    2015-07-01

    Full Text Available One of the most important roles in the machine learning area is to classify, and neural networks are very important classifiers. However, traditional neural networks cannot identify intervals, let alone classify them. To improve their identification ability, we propose a neural network-based interval matcher in our paper. After summarizing the theoretical construction of the model, we take a simple and a practical weather forecasting experiment, which show that the recognizer accuracy reaches 100% and that is promising.

  14. The Outlier Interval Detection Algorithms on Astronautical Time Series Data

    Directory of Open Access Journals (Sweden)

    Wei Hu

    2013-01-01

    Full Text Available The Outlier Interval Detection is a crucial technique to analyze spacecraft fault, locate exception, and implement intelligent fault diagnosis system. The paper proposes two OID algorithms on astronautical Time Series Data, that is, variance based OID (VOID and FFT and k nearest Neighbour based OID (FKOID. The VOID algorithm divides TSD into many intervals and measures each interval’s outlier score according to its variance. This algorithm can detect the outlier intervals with great fluctuation in the time domain. It is a simple and fast algorithm with less time complexity, but it ignores the frequency information. The FKOID algorithm extracts the frequency information of each interval by means of Fast Fourier Transform, so as to calculate the distances between frequency features, and adopts the KNN method to measure the outlier score according to the sum of distances between the interval’s frequency vector and the K nearest frequency vectors. It detects the outlier intervals in a refined way at an appropriate expense of the time and is valid to detect the outlier intervals in both frequency and time domains.

  15. Diverticulosis and the risk of interval colorectal cancer.

    Science.gov (United States)

    Cooper, Gregory S; Xu, Fang; Schluchter, Mark D; Koroukian, Siran M; Barnholtz Sloan, Jill S

    2014-11-01

    Diverticulosis, a prevalent condition at screening colonoscopy, has been associated with colorectal cancers that develop after a clearing colonoscopy, or interval cancers. To quantify the overall risk of diverticulosis in the development of interval cancers and examine this association in relevant subgroups. Using a linked database containing SEER tumor registry data and Medicare claims, we identified patients aged ≥69 years with colorectal cancer who underwent colonoscopy within 6 months of diagnosis. Patients with an additional colonoscopy from 36 to 6 months prior to cancer diagnosis were characterized as having interval cancers. We compared characteristics of patients with interval cancers and detected cancers according to a diagnosis of diverticulosis not associated with a colonoscopy procedure from 1991 through the date of the most recent colonoscopy in both univariate and multivariate models. A previous diagnosis of diverticulosis was documented in 14,452 (26.9 %) patients with detected cancers compared to 2,905 (69.3 %) patients with interval cancers (p diverticulosis diagnoses were without complications such as hemorrhage or diverticulitis. Diverticulosis was strongly associated with interval colorectal cancers in all segments of the colon. Given its known predominance in the left colon, the findings argue against impaired visualization of lesions at colonoscopy as the only pathogenic factor.

  16. Procrastination by pigeons with fixed-interval response requirements.

    Science.gov (United States)

    Mazur, J E

    1998-01-01

    Two experiments studied the phenomenon of procrastination, in which pigeons chose a larger, more delayed response requirement over a smaller, more immediate response requirement. The response requirements were fixed-interval schedules that did not lead to an immediate food reinforcer, but that interrupted a 55-s period in which food was delivered at random times. The experiments used an adjusting-delay procedure in which the delay to the start of one fixed-interval requirement was varied over trials to estimate an indifference point--a delay at which the two alternatives were chosen about equally often. Experiment 1 found that as the delay to a shorter fixed-interval requirement was increased, the adjusting delay to a longer fixed-interval requirement also increased, and the rate of increase depended on the duration of the longer fixed-interval requirement. Experiment 2 found a strong preference for a fixed delay of 10 s to the start of a fixed-interval requirement compared to a mixed delay of either 0 or 20 s. The results help to distinguish among different equations that might describe the decreasing effectiveness of a response requirement with increasing delay, and they suggest that delayed reinforcers and delayed response requirements have symmetrical but opposite effects on choice. PMID:9540230

  17. Evidence-based approach to harmonised reference intervals.

    Science.gov (United States)

    Koerbin, Gus; Sikaris, Ken Andrew; Jones, Graham Ross Dallas; Ryan, Julie; Reed, Maxine; Tate, Jill

    2014-05-15

    Although we are in the era of evidence-based medicine, there is still a substantial gap between theory and current practice with the application of reference intervals as decision making tools. Different laboratories may have different reference intervals for the same tests using the same analytical methods and platforms. These differences have the potential to confuse physicians making the assessment and monitoring of patients more difficult by providing discordant information. This paper attempts to demonstrate how to use evidence-based approach for harmonising reference intervals. In order to consider harmonisation we must first have an appreciation of the various factors that influence the determination of that reference interval such as the choice of individuals within the population studied, biological variability of the analyte studied, partitioning, sample collection, analytical aspects such as bias and statistical models. An a priori approach for determining reference intervals, whilst recommended, may be beyond the scope of most laboratories and consideration should be given to the use of a validated indirect a posteriori approach. Regardless of method used, the continuing application of an evidence-based approach in harmonised reference intervals to meet the quality expectations of physicians should be pursued. © 2013.

  18. Establishment of hematological reference intervals for healthy adults in Asmara.

    Science.gov (United States)

    Siraj, Nejat; Issac, John; Anwar, Mohammed; Mehari, Yohannes; Russom, Shushan; Kahsay, Semere; Frezghi, Haben

    2018-01-22

    Clinical laboratory reference intervals used in a specific area should be derived from the local population as they are influenced by many factors. The purpose of this quantitative cross sectional study was to establish hematological reference intervals for healthy adults in Asmara and to determine whether the currently used reference interval do represent the adult population in the city. In addition, the established reference intervals were compared to findings from similar studies conducted in selected countries in Africa. There was a significant difference between males and females in the reference intervals for erythrocyte count, hemoglobin, hematocrit, mean cell volume, mean cell hemoglobin, mean cell hemoglobin concentration and differential white blood cell count. All the evaluated hematological analytes were found to be higher in males than in females except for platelet count. The out of range percentage for the parameters extends from 3.5 to 46.7%; with red blood cell count having the lowest while mean cell volume having the highest out of range percentage. The results indicated that the currently used reference interval does not represent the population in Asmara and are different from those obtained elsewhere in Africa.

  19. Identification of atrial fibrillation using electrocardiographic RR-interval difference

    Science.gov (United States)

    Eliana, M.; Nuryani, N.

    2017-11-01

    Automated detection of atrial fibrillation (AF) is an interesting topic. It is an account of very dangerous, not only as a trigger of embolic stroke, but it’s also related to some else chronical disease. In this study, we analyse the presence of AF by determining irregularities of RR-interval. We utilize the interval comparison to measure the degree of irregularities of RR-interval in a defined segment. The series of RR-interval is segmented with the length of 10 of them. In this study, we use interval comparison for the method. We were comparing all of the intervals there each other. Then we put the threshold to define the low difference and high difference (δ). A segment is defined as AF or Normal Sinus by the number of high δ, so we put the tolerance (β) of high δ there. We have used this method to test the 23 patients data from MIT-BIH. Using the approach and the clinical data we find accuracy, sensitivity, and specificity of 84.98%, 91.99%, and 77.85% respectively.

  20. Influence Of Inspection Intervals On Mechanical System Reliability

    International Nuclear Information System (INIS)

    Zilberman, B.

    1998-01-01

    In this paper a methodology of reliability analysis of mechanical systems with latent failures is described. Reliability analysis of such systems must include appropriate usage of check intervals for latent failure detection. The methodology suggests, that based on system logic the analyst decides at the beginning if a system can fail actively or latently and propagates this approach through all system levels. All inspections are assumed to be perfect (all failures are detected and repaired and no new failures are introduced as a result of the maintenance). Additional assumptions are that mission time is much smaller, than check intervals and all components have constant failure rates. Analytical expressions for reliability calculates are provided, based on fault tree and Markov modeling techniques (for two and three redundant systems with inspection intervals). The proposed methodology yields more accurate results than are obtained by not using check intervals or using half check interval times. The conventional analysis assuming that at the beginning of each mission system is as new, give an optimistic prediction of system reliability. Some examples of reliability calculations of mechanical systems with latent failures and establishing optimum check intervals are provided

  1. Modulation of motor cortex excitability by paired peripheral and transcranial magnetic stimulation.

    Science.gov (United States)

    Kumru, Hatice; Albu, Sergiu; Rothwell, John; Leon, Daniel; Flores, Cecilia; Opisso, Eloy; Tormos, Josep Maria; Valls-Sole, Josep

    2017-10-01

    Repetitive application of peripheral electrical stimuli paired with transcranial magnetic stimulation (rTMS) of M1 cortex at low frequency, known as paired associative stimulation (PAS), is an effective method to induce motor cortex plasticity in humans. Here we investigated the effects of repetitive peripheral magnetic stimulation (rPMS) combined with low frequency rTMS ('magnetic-PAS') on intracortical and corticospinal excitability and whether those changes were widespread or circumscribed to the cortical area controlling the stimulated muscle. Eleven healthy subjects underwent three 10min stimulation sessions: 10HzrPMS alone, applied in trains of 5 stimuli every 10s (60 trains) on the extensor carpi radialis (ECR) muscle; rTMS alone at an intensity 120% of ECR threshold, applied over motor cortex of ECR and at a frequency of 0.1Hz (60 stimuli) and magnetic PAS, i.e., paired rPMS and rTMS. We recorded motor evoked potentials (MEPs) from ECR and first dorsal interosseous (FDI) muscles. We measured resting motor threshold, motor evoked potentials (MEP) amplitude at 120% of RMT, short intracortical inhibition (SICI) at interstimulus interval (ISI) of 2ms and intracortical facilitation (ICF) at an ISI of 15ms before and immediately after each intervention. Magnetic-PAS , but not rTMS or rPMS applied separately, increased MEP amplitude and reduced short intracortical inhibition in ECR but not in FDI muscle. Magnetic-PAS can increase corticospinal excitability and reduce intracortical inhibition. The effects may be specific for the area of cortical representation of the stimulated muscle. Application of magnetic-PAS might be relevant for motor rehabilitation. Copyright © 2017 International Federation of Clinical Neurophysiology. All rights reserved.

  2. Event- and interval-based measurement of stuttering: a review.

    Science.gov (United States)

    Valente, Ana Rita S; Jesus, Luis M T; Hall, Andreia; Leahy, Margaret

    2015-01-01

    Event- and interval-based measurements are two different ways of computing frequency of stuttering. Interval-based methodology emerged as an alternative measure to overcome problems associated with reproducibility in the event-based methodology. No review has been made to study the effect of methodological factors in interval-based absolute reliability data or to compute the agreement between the two methodologies in terms of inter-judge, intra-judge and accuracy (i.e., correspondence between raters' scores and an established criterion). To provide a review related to reproducibility of event-based and time-interval measurement, and to verify the effect of methodological factors (training, experience, interval duration, sample presentation order and judgment conditions) on agreement of time-interval measurement; in addition, to determine if it is possible to quantify the agreement between the two methodologies The first two authors searched for articles on ERIC, MEDLINE, PubMed, B-on, CENTRAL and Dissertation Abstracts during January-February 2013 and retrieved 495 articles. Forty-eight articles were selected for review. Content tables were constructed with the main findings. Articles related to event-based measurements revealed values of inter- and intra-judge greater than 0.70 and agreement percentages beyond 80%. The articles related to time-interval measures revealed that, in general, judges with more experience with stuttering presented significantly higher levels of intra- and inter-judge agreement. Inter- and intra-judge values were beyond the references for high reproducibility values for both methodologies. Accuracy (regarding the closeness of raters' judgements with an established criterion), intra- and inter-judge agreement were higher for trained groups when compared with non-trained groups. Sample presentation order and audio/video conditions did not result in differences in inter- or intra-judge results. A duration of 5 s for an interval appears to be

  3. Interval MULTIMOORA method with target values of attributes based on interval distance and preference degree: biomaterials selection

    Science.gov (United States)

    Hafezalkotob, Arian; Hafezalkotob, Ashkan

    2017-12-01

    A target-based MADM method covers beneficial and non-beneficial attributes besides target values for some attributes. Such techniques are considered as the comprehensive forms of MADM approaches. Target-based MADM methods can also be used in traditional decision-making problems in which beneficial and non-beneficial attributes only exist. In many practical selection problems, some attributes have given target values. The values of decision matrix and target-based attributes can be provided as intervals in some of such problems. Some target-based decision-making methods have recently been developed; however, a research gap exists in the area of MADM techniques with target-based attributes under uncertainty of information. We extend the MULTIMOORA method for solving practical material selection problems in which material properties and their target values are given as interval numbers. We employ various concepts of interval computations to reduce degeneration of uncertain data. In this regard, we use interval arithmetic and introduce innovative formula for interval distance of interval numbers to create interval target-based normalization technique. Furthermore, we use a pairwise preference matrix based on the concept of degree of preference of interval numbers to calculate the maximum, minimum, and ranking of these numbers. Two decision-making problems regarding biomaterials selection of hip and knee prostheses are discussed. Preference degree-based ranking lists for subordinate parts of the extended MULTIMOORA method are generated by calculating the relative degrees of preference for the arranged assessment values of the biomaterials. The resultant rankings for the problem are compared with the outcomes of other target-based models in the literature.

  4. Psychoacoustic Factors in Musical Intonation: Beats, Interval Tuning, and Inharmonicity.

    Science.gov (United States)

    Keislar, Douglas Fleming

    Three psychoacoustic experiments were conducted using musically experienced subjects. In the first two experiments, the interval tested was the perfect fifth F4-C5; in the final one it was the major third F4-A4. The beat rate was controlled by two different methods: (1) simply retuning the interval, and (2) frequency-shifting one partial of each pair of beating partials without changing the overall interval tuning. The second method introduces inharmonicity. In addition, two levels of beat amplitude were introduced by using either a complete spectrum of 16 equal-amplitude partials per note, or by deleting one partial from each pair of beating partials. The results of all three experiments indicate that, for these stimuli, beating does not contribute significantly to the percept of "out-of-tuneness," because it made no difference statistically whether the beat amplitude was maximal or minimal. By contrast, mistuning the interval was highly significant. For the fifths, frequency-shifting the appropriate partials had about as much effect on the perceived intonation as mistuning the interval. For thirds, this effect was weaker, presumably since there were fewer inharmonic partials and they were higher in the harmonic series. Subjects were less consistent in their judgments of thirds than of fifths, perhaps because the equal-tempered and just thirds differ noticeably, unlike fifths. Since it is unlikely that beats would be more audible in real musical situations than under these laboratory conditions, these results suggest that the perception of intonation in music is dependent on the actual interval tuning rather than the concomitant beat rate. If beating partials are unimportant vis-a-vis interval tuning, this strengthens the argument for a cultural basis for musical intonation and scales, as opposed to the acoustical basis set forth by Helmholtz and others.

  5. EFFECT OF INTERPREGNANCY INTERVAL ON SUBSEQUENT PREGNANCY FOLLOWING A MISCARRIAGE

    Directory of Open Access Journals (Sweden)

    Anasooya Parail Sankaran

    2017-03-01

    Full Text Available BACKGROUND Primary Objective of this study was to determine the effect on interpregnancy interval on subsequent pregnancies after a miscarriage. Secondary Objective was to study the maternal and foetal complications following shorter interpregnancy interval. MATERIALS AND METHODS This study was done in OBG Department, Government TD Medical College, Alappuzha, during 2011 to 2013. A total of 347 cases were studied who have had a miscarriage before the current pregnancy. RESULTS Compared with women with an interpregnancy interval of 6-12 months, those who conceived again within six months were more likely to have another miscarriage and ectopic gestation (odds ratio 0.106, p value 0.000.. Compared with women with interpregnancy interval of <6 months, women who conceived again in 6-12 months went on to have a vaginal delivery in the second pregnancy (Odd’s ratio 0.79 and p value in is significant.Lower segment caesarean section (LSCS is significantly high in women whose interpregnancy interval is more than 12 months (Odds ratio 0.64 and p value 0.000. Maternal complications like APH, PPH, preeclampsia, hypertension, etc. were significantly seen higher in women whose interpregnancy interval is more than 12 months (odds ratio 0.41 p value- 0.000. The women with interpregnancy interval less than 6 months didn’t develop any significant foetal complications. Most of the complications like premature rupture of membrane (PROM, meconium stained amniotic fluid (MSAF, oligamnios, foetal growth restriction (FGR, etc. are seen more in the women with interpregnancy interval 6 to 12 months odds ratio (0.30 p value significant, but breech and foetal distress are seen significantly higher in women with interpregnancy interval more than 12 months (Odds ratio 0.29 p value 0.000. Induction of labour was not significantly raised in any group. CONCLUSION Women who conceive within 6 months of an initial miscarriage have the best reproductive outcomes and lower

  6. Interval forecasting of cyber-attacks on industrial control systems

    Science.gov (United States)

    Ivanyo, Y. M.; Krakovsky, Y. M.; Luzgin, A. N.

    2018-03-01

    At present, cyber-security issues of industrial control systems occupy one of the key niches in a state system of planning and management Functional disruption of these systems via cyber-attacks may lead to emergencies related to loss of life, environmental disasters, major financial and economic damage, or disrupted activities of cities and settlements. There is then an urgent need to develop protection methods against cyber-attacks. This paper studied the results of cyber-attack interval forecasting with a pre-set intensity level of cyber-attacks. Interval forecasting is the forecasting of one interval from two predetermined ones in which a future value of the indicator will be obtained. For this, probability estimates of these events were used. For interval forecasting, a probabilistic neural network with a dynamic updating value of the smoothing parameter was used. A dividing bound of these intervals was determined by a calculation method based on statistical characteristics of the indicator. The number of cyber-attacks per hour that were received through a honeypot from March to September 2013 for the group ‘zeppo-norcal’ was selected as the indicator.

  7. Interval vs massed training: how best do we teach surgery?

    Science.gov (United States)

    Kesser, Bradley W; Hallman, Matthew; Murphy, Loren; Tillar, Maggie; Keeley, Meg; Peirce, Shayn

    2014-01-01

    To compare 2 different training paradigms, massed vs interval training, when novice students learn a surgical procedure, myringotomy with ventilation tube insertion, on a validated surgical simulator. Medical students were randomized into 2 training groups: the interval group (n = 19) was trained to perform the procedure in 5 trials/d over 3 days, and the massed group (n = 21) was trained to perform the procedure in 15 trials all in 1 session. One week later, all students were tested in 5 additional final trials. Pre- and posttest surveys were administered. Academic medical center. Forty medical students: 19 students in the interval group were compared with 21 students in the massed group. Time to complete the procedure and number and type of error made were recorded and compared between groups. Pre- and poststudy surveys examined confidence levels working under a microscope and with the procedure. Students in both groups had a significant decrease in time between practice and final trials. In the final 5 trials, there was no difference in average time to complete the procedure between the massed and interval training groups. No difference was observed in the number of errors committed per trial between initial and final trials (both groups) or between massed and interval training groups. The students' confidence levels significantly increased across the trials, regardless of group. Surgical training improves proficiency, but method of training had little impact on proficiency in performing a simulated surgical procedure in this setting.

  8. Energy compensation after sprint- and high-intensity interval training.

    Science.gov (United States)

    Schubert, Matthew M; Palumbo, Elyse; Seay, Rebekah F; Spain, Katie K; Clarke, Holly E

    2017-01-01

    Many individuals lose less weight than expected in response to exercise interventions when considering the increased energy expenditure of exercise (ExEE). This is due to energy compensation in response to ExEE, which may include increases in energy intake (EI) and decreases in non-exercise physical activity (NEPA). We examined the degree of energy compensation in healthy young men and women in response to interval training. Data were examined from a prior study in which 24 participants (mean age, BMI, & VO2max = 28 yrs, 27.7 kg•m-2, and 32 mL∙kg-1∙min-1) completed either 4 weeks of sprint-interval training or high-intensity interval training. Energy compensation was calculated from changes in body composition (air displacement plethysmography) and exercise energy expenditure was calculated from mean heart rate based on the heart rate-VO2 relationship. Differences between high (≥ 100%) and low (interval training. In agreement with prior work, increases in ΔVO2max and ΔNEPA were associated with lower energy compensation. Future studies should focus on identifying if a dose-response relationship for energy compensation exists in response to interval training, and what underlying mechanisms and participant traits contribute to the large variation between individuals.

  9. Interval-Valued Rank in Finite Ordered Sets

    Energy Technology Data Exchange (ETDEWEB)

    Joslyn, Cliff; Pogel, Alex; Purvine, Emilie

    2016-11-12

    We consider the concept of rank as a measure of the vertical levels and positions of elements of partially ordered sets (posets). We are motivated by the need for algorithmic measures on large, real-world hierarchically-structured data objects like the semantic hierarchies of ontolog- ical databases. These rarely satisfy the strong property of gradedness, which is required for traditional rank functions to exist. Representing such semantic hierarchies as finite, bounded posets, we recognize the duality of ordered structures to motivate rank functions which respect verticality both from the bottom and from the top. Our rank functions are thus interval-valued, and always exist, even for non-graded posets, providing order homomorphisms to an interval order on the interval-valued ranks. The concept of rank width arises naturally, allowing us to identify the poset region with point-valued width as its longest graded portion (which we call the “spindle”). A standard interval rank function is naturally motivated both in terms of its extremality and on pragmatic grounds. Its properties are examined, including the relation- ship to traditional grading and rank functions, and methods to assess comparisons of standard interval-valued ranks.

  10. A Comparative Study on Decision Making Methods with Interval Data

    Directory of Open Access Journals (Sweden)

    Aditya Chauhan

    2014-01-01

    Full Text Available Multiple Criteria Decision Making (MCDM models are used to solve a number of decision making problems universally. Most of these methods require the use of integers as input data. However, there are problems which have indeterminate values or data intervals which need to be analysed. In order to solve problems with interval data, many methods have been reported. Through this study an attempt has been made to compare and analyse the popular decision making tools for interval data problems. Namely, I-TOPSIS (Technique for Order Preference by Similarity to Ideal Solution, DI-TOPSIS, cross entropy, and interval VIKOR (VlseKriterijumska Optimiza-cija I Kompromisno Resenje have been compared and a novel algorithm has been proposed. The new algorithm makes use of basic TOPSIS technique to overcome the limitations of known methods. To compare the effectiveness of the various methods, an example problem has been used where selection of best material family for the capacitor application has to be made. It was observed that the proposed algorithm is able to overcome the known limitations of the previous techniques. Thus, it can be easily and efficiently applied to various decision making problems with interval data.

  11. Chinese Pediatric Reference Intervals for Serum Cortisol on IMMULITE 2000.

    Science.gov (United States)

    Wang, Ling Li; Zhang, Li Yue; Wang, Hui Yan; Wen, Huai Kai; Tao, Hong Qun; Zhao, Xiao Wei

    2018-01-01

    Clinical interpretation of the test results for cortisol based on continuous reference intervals with appropriate partitions improves pediatric diagnosis; however, these values are available only for Caucasians. To develop the pediatric reference intervals for Chinese population, we examined the serum cortisol levels in 1,143 healthy Chinese children aged 4-18 years (566 boys and 577 girls), using an IMMULITE 2000 Immunoassay System (Siemens Healthcare GmbH). Phlebotomy was performed at 7-9 a.m. for 284 boys and 287 girls and at 1-3 p.m. for the others. They were divided into four age groups according to the Clinical and Laboratory Standards Institute guideline EP28-A3c, with the last group further stratified according to sampling time. Separate reference intervals of 49.6-323.7, 70.9-395.3, and 90.1-448.7 nmol/L were established for children aged 4-8, 9-12, and 13-15 years, respectively. Further, reference intervals of 118.2-464.7 and 71.4-446.7 nmol/L were established for morning and afternoon cortisol levels, respectively, in children aged 16-18 years. Further studies are necessary to transfer and validate these reference intervals in other analytical systems and pediatric populations, and to allow for broader applications. © The Korean Society for Laboratory Medicine.

  12. Confidence intervals in temperature-based death time determination.

    Science.gov (United States)

    Hubig, Michael; Muggenthaler, Holger; Mall, Gita

    2015-01-01

    Marshall and Hoare's double exponential model with Henßge's parameters is a well known method for temperature based death time estimation. The authors give 95%-confidence intervals for their method. Since body cooling is a complex thermodynamical process, one has to take into account a potential bias of the estimator. This quantity measures the systematic error of the estimators underlying model. For confidence interval radius calculation a bias of 0 is presupposed, therefore the actual probability of the true death time value to lie in the 95%-confidence interval can be much lower than 95% in case of nonvanishing bias. As in case of nonstandard conditions the confidence intervals have a probability of containing the true death time value which even in case of small corrective factor errors of Δ = ± 0.1 can be substantially smaller than the 95% claimed, the paper presents a formula for confidence intervals which keep a 95% probability in case of error Δc ⩽ ± 0.1. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  13. Bootstrap confidence intervals for the process capability index under half-logistic distribution

    OpenAIRE

    Wararit Panichkitkosolkul

    2012-01-01

    This study concerns the construction of bootstrap confidence intervals for theprocess capability index in the case of half-logistic distribution. The bootstrap confidence intervals applied consist of standard bootstrap confidence interval, percentile bootstrap confidence interval and bias-corrected percentile bootstrap confidence interval. Using Monte Carlo simulations, the estimated coverage probabilities and average widths ofbootstrap confidence intervals are compared, with results showing ...

  14. Rapid storage and retrieval of genomic intervals from a relational database system using nested containment lists.

    Science.gov (United States)

    Wiley, Laura K; Sivley, R Michael; Bush, William S

    2013-01-01

    Efficient storage and retrieval of genomic annotations based on range intervals is necessary, given the amount of data produced by next-generation sequencing studies. The indexing strategies of relational database systems (such as MySQL) greatly inhibit their use in genomic annotation tasks. This has led to the development of stand-alone applications that are dependent on flat-file libraries. In this work, we introduce MyNCList, an implementation of the NCList data structure within a MySQL database. MyNCList enables the storage, update and rapid retrieval of genomic annotations from the convenience of a relational database system. Range-based annotations of 1 million variants are retrieved in under a minute, making this approach feasible for whole-genome annotation tasks. Database URL: https://github.com/bushlab/mynclist.

  15. Beneficial bacteria inhibit cachexia

    Science.gov (United States)

    Varian, Bernard J.; Goureshetti, Sravya; Poutahidis, Theofilos; Lakritz, Jessica R.; Levkovich, Tatiana; Kwok, Caitlin; Teliousis, Konstantinos; Ibrahim, Yassin M.; Mirabal, Sheyla; Erdman, Susan E.

    2016-01-01

    Muscle wasting, known as cachexia, is a debilitating condition associated with chronic inflammation such as during cancer. Beneficial microbes have been shown to optimize systemic inflammatory tone during good health; however, interactions between microbes and host immunity in the context of cachexia are incompletely understood. Here we use mouse models to test roles for bacteria in muscle wasting syndromes. We find that feeding of a human commensal microbe, Lactobacillus reuteri, to mice is sufficient to lower systemic indices of inflammation and inhibit cachexia. Further, the microbial muscle-building phenomenon extends to normal aging as wild type animals exhibited increased growth hormone levels and up-regulation of transcription factor Forkhead Box N1 [FoxN1] associated with thymus gland retention and longevity. Interestingly, mice with a defective FoxN1 gene (athymic nude) fail to inhibit sarcopenia after L. reuteri therapy, indicating a FoxN1-mediated mechanism. In conclusion, symbiotic bacteria may serve to stimulate FoxN1 and thymic functions that regulate inflammation, offering possible alternatives for cachexia prevention and novel insights into roles for microbiota in mammalian ontogeny and phylogeny. PMID:26933816

  16. Rationalizing method of replacement intervals by using Bayesian statistics

    International Nuclear Information System (INIS)

    Kasai, Masao; Notoya, Junichi; Kusakari, Yoshiyuki

    2007-01-01

    This study represents the formulations for rationalizing the replacement intervals of equipments and/or parts taking into account the probability density functions (PDF) of the parameters of failure distribution functions (FDF) and compares the optimized intervals by our formulations with those by conventional formulations which uses only representative values of the parameters of FDF instead of using these PDFs. The failure data are generated by Monte Carlo simulations since the real failure data can not be available for us. The PDF of PDF parameters are obtained by Bayesian method and the representative values are obtained by likelihood estimation and Bayesian method. We found that the method using PDF by Bayesian method brings longer replacement intervals than one using the representative of the parameters. (author)

  17. INTERVALS OF ACTIVE PLAY AND BREAK IN BASKETBALL GAMES

    Directory of Open Access Journals (Sweden)

    Pavle Rubin

    2010-09-01

    Full Text Available The problem of the research comes from the need for decomposition of a basketball game. The aim was to determine the intervals of active game (“live ball” - term defined by rules and break (“dead ball” - term defined by rules, by analyzing basketball games. In order to obtain the relevant information, basketball games from five different competitions (top level of quality were analyzed. The sample consists of seven games played in the 2006/2007 season: NCAA Play - Off Final game, Adriatic League finals, ULEB Cup final game, Euroleague (2 games and the NBA league (2 games. The most important information gained by this research is that the average interval of active play lasts approximately 47 seconds, while the average break interval lasts approximately 57 seconds. This information is significant for coaches and should be used in planning the training process.

  18. Trajectory Optimization Based on Multi-Interval Mesh Refinement Method

    Directory of Open Access Journals (Sweden)

    Ningbo Li

    2017-01-01

    Full Text Available In order to improve the optimization accuracy and convergence rate for trajectory optimization of the air-to-air missile, a multi-interval mesh refinement Radau pseudospectral method was introduced. This method made the mesh endpoints converge to the practical nonsmooth points and decreased the overall collocation points to improve convergence rate and computational efficiency. The trajectory was divided into four phases according to the working time of engine and handover of midcourse and terminal guidance, and then the optimization model was built. The multi-interval mesh refinement Radau pseudospectral method with different collocation points in each mesh interval was used to solve the trajectory optimization model. Moreover, this method was compared with traditional h method. Simulation results show that this method can decrease the dimensionality of nonlinear programming (NLP problem and therefore improve the efficiency of pseudospectral methods for solving trajectory optimization problems.

  19. Interpregnancy intervals: impact of postpartum contraceptive effectiveness and coverage.

    Science.gov (United States)

    Thiel de Bocanegra, Heike; Chang, Richard; Howell, Mike; Darney, Philip

    2014-04-01

    The purpose of this study was to determine the use of contraceptive methods, which was defined by effectiveness, length of coverage, and their association with short interpregnancy intervals, when controlling for provider type and client demographics. We identified a cohort of 117,644 women from the 2008 California Birth Statistical Master file with second or higher order birth and at least 1 Medicaid (Family Planning, Access, Care, and Treatment [Family PACT] program or Medi-Cal) claim within 18 months after index birth. We explored the effect of contraceptive method provision on the odds of having an optimal interpregnancy interval and controlled for covariates. The average length of contraceptive coverage was 3.81 months (SD = 4.84). Most women received user-dependent hormonal contraceptives as their most effective contraceptive method (55%; n = 65,103 women) and one-third (33%; n = 39,090 women) had no contraceptive claim. Women who used long-acting reversible contraceptive methods had 3.89 times the odds and women who used user-dependent hormonal methods had 1.89 times the odds of achieving an optimal birth interval compared with women who used barrier methods only; women with no method had 0.66 times the odds. When user-dependent methods are considered, the odds of having an optimal birth interval increased for each additional month of contraceptive coverage by 8% (odds ratio, 1.08; 95% confidence interval, 1.08-1.09). Women who were seen by Family PACT or by both Family PACT and Medi-Cal providers had significantly higher odds of optimal birth intervals compared with women who were served by Medi-Cal only. To achieve optimal birth spacing and ultimately to improve birth outcomes, attention should be given to contraceptive counseling and access to contraceptive methods in the postpartum period. Copyright © 2014 Mosby, Inc. All rights reserved.

  20. Persistent fluctuations in stride intervals under fractal auditory stimulation.

    Science.gov (United States)

    Marmelat, Vivien; Torre, Kjerstin; Beek, Peter J; Daffertshofer, Andreas

    2014-01-01

    Stride sequences of healthy gait are characterized by persistent long-range correlations, which become anti-persistent in the presence of an isochronous metronome. The latter phenomenon is of particular interest because auditory cueing is generally considered to reduce stride variability and may hence be beneficial for stabilizing gait. Complex systems tend to match their correlation structure when synchronizing. In gait training, can one capitalize on this tendency by using a fractal metronome rather than an isochronous one? We examined whether auditory cues with fractal variations in inter-beat intervals yield similar fractal inter-stride interval variability as isochronous auditory cueing in two complementary experiments. In Experiment 1, participants walked on a treadmill while being paced by either an isochronous or a fractal metronome with different variation strengths between beats in order to test whether participants managed to synchronize with a fractal metronome and to determine the necessary amount of variability for participants to switch from anti-persistent to persistent inter-stride intervals. Participants did synchronize with the metronome despite its fractal randomness. The corresponding coefficient of variation of inter-beat intervals was fixed in Experiment 2, in which participants walked on a treadmill while being paced by non-isochronous metronomes with different scaling exponents. As expected, inter-stride intervals showed persistent correlations similar to self-paced walking only when cueing contained persistent correlations. Our results open up a new window to optimize rhythmic auditory cueing for gait stabilization by integrating fractal fluctuations in the inter-beat intervals.

  1. Measurement of subcritical multiplication by the interval distribution method

    International Nuclear Information System (INIS)

    Nelson, G.W.

    1985-01-01

    The prompt decay constant or the subcritical neutron multiplication may be determined by measuring the distribution of the time intervals between successive neutron counts. The distribution data is analyzed by least-squares fitting to a theoretical distribution function derived from a point reactor probability model. Published results of measurements with one- and two-detector systems are discussed. Data collection times are shorter, and statistical errors are smaller the nearer the system is to delayed critical. Several of the measurements indicate that a shorter data collection time and higher accuracy are possible with the interval distribution method than with the Feynman variance method

  2. Fuzzy Investment Portfolio Selection Models Based on Interval Analysis Approach

    Directory of Open Access Journals (Sweden)

    Haifeng Guo

    2012-01-01

    Full Text Available This paper employs fuzzy set theory to solve the unintuitive problem of the Markowitz mean-variance (MV portfolio model and extend it to a fuzzy investment portfolio selection model. Our model establishes intervals for expected returns and risk preference, which can take into account investors' different investment appetite and thus can find the optimal resolution for each interval. In the empirical part, we test this model in Chinese stocks investment and find that this model can fulfill different kinds of investors’ objectives. Finally, investment risk can be decreased when we add investment limit to each stock in the portfolio, which indicates our model is useful in practice.

  3. An interval-valued reliability model with bounded failure rates

    DEFF Research Database (Denmark)

    Kozine, Igor; Krymsky, Victor

    2012-01-01

    The approach to deriving interval-valued reliability measures described in this paper is distinctive from other imprecise reliability models in that it overcomes the issue of having to impose an upper bound on time to failure. It rests on the presupposition that a constant interval-valued failure...... rate is known possibly along with other reliability measures, precise or imprecise. The Lagrange method is used to solve the constrained optimization problem to derive new reliability measures of interest. The obtained results call for an exponential-wise approximation of failure probability density...... function if only partial failure information is available. An example is provided. © 2012 Copyright Taylor and Francis Group, LLC....

  4. Control of Angular Intervals for Angle-Multiplexed Holographic Memory

    Science.gov (United States)

    Kinoshita, Nobuhiro; Muroi, Tetsuhiko; Ishii, Norihiko; Kamijo, Koji; Shimidzu, Naoki

    2009-03-01

    In angle-multiplexed holographic memory, the full width at half maximum of the Bragg selectivity curves is dependent on the angle formed between the medium and incident laser beams. This indicates the possibility of high density and high multiplexing number by varying the angular intervals between adjacent holograms. We propose an angular interval scheduling for closely stacking holograms into medium even when the angle range is limited. We obtained bit error rates of the order of 10-4 under the following conditions: medium thickness of 1 mm, laser beam wavelength of 532 nm, and angular multiplexing number of 300.

  5. Explicit Inverse of an Interval Matrix with Unit Midpoint

    Czech Academy of Sciences Publication Activity Database

    Rohn, Jiří

    2011-01-01

    Roč. 22, - (2011), s. 138-150 E-ISSN 1081-3810 R&D Projects: GA ČR GA201/09/1957; GA ČR GC201/08/J020 Institutional research plan: CEZ:AV0Z10300504 Keywords : interval matrix * unit midpoint * inverse interval matrix * regularity Subject RIV: BA - General Mathematics Impact factor: 0.808, year: 2010 http://www.math.technion.ac.il/iic/ela/ela-articles/articles/vol22_pp138-150.pdf

  6. Robust Control with Enlaeged Interval of Uncertain Parameters

    Directory of Open Access Journals (Sweden)

    Marek Keresturi

    2002-01-01

    Full Text Available Robust control is advantageous for systems with defined interval of uncertain parameters. This can be substantially enlarged dividing it into a few sub-intervals. Corresponding controllers for each of them may be set after approximate identification of some uncertain plant parameters. The paper deals with application of the pole region assignment method for position control of the crane crab. The same track form is required for uncertain burden mass and approximate value of rope length. Measurement of crab position and speed is supposed, burden deviation angle is observed. Simulation results have verified feasibility of this design procedure.

  7. New Inner Product Quasilinear Spaces on Interval Numbers

    Directory of Open Access Journals (Sweden)

    Hacer Bozkurt

    2016-01-01

    Full Text Available Primarily we examine the new example of quasilinear spaces, namely, “IRn interval space.” We obtain some new theorems and results related to this new quasilinear space. After giving some new notions of quasilinear dependence-independence and basis on quasilinear functional analysis, we obtain some results on IRn interval space related to these concepts. Secondly, we present Is,Ic0,Il∞, and Il2 quasilinear spaces and we research some algebraic properties of these spaces. We obtain some new results and provide an important contribution to the improvement of quasilinear functional analysis.

  8. Infinite time interval backward stochastic differential equations with continuous coefficients.

    Science.gov (United States)

    Zong, Zhaojun; Hu, Feng

    2016-01-01

    In this paper, we study the existence theorem for [Formula: see text] [Formula: see text] solutions to a class of 1-dimensional infinite time interval backward stochastic differential equations (BSDEs) under the conditions that the coefficients are continuous and have linear growths. We also obtain the existence of a minimal solution. Furthermore, we study the existence and uniqueness theorem for [Formula: see text] [Formula: see text] solutions of infinite time interval BSDEs with non-uniformly Lipschitz coefficients. It should be pointed out that the assumptions of this result is weaker than that of Theorem 3.1 in Zong (Turkish J Math 37:704-718, 2013).

  9. Estimation and interpretation of keff confidence intervals in MCNP

    International Nuclear Information System (INIS)

    Urbatsch, T.J.

    1995-11-01

    MCNP's criticality methodology and some basic statistics are reviewed. Confidence intervals are discussed, as well as how to build them and their importance in the presentation of a Monte Carlo result. The combination of MCNP's three k eff estimators is shown, theoretically and empirically, by statistical studies and examples, to be the best k eff estimator. The method of combining estimators is based on a solid theoretical foundation, namely, the Gauss-Markov Theorem in regard to the least squares method. The confidence intervals of the combined estimator are also shown to have correct coverage rates for the examples considered

  10. Frequency Interval Cross Gramians for Linear and Bilinear Systems

    DEFF Research Database (Denmark)

    Jazlan, Ahmad; Sreeram, Victor; Shaker, Hamid Reza

    2017-01-01

    the frequency interval cross gramians are derived in order to be used to obtain information regarding controllability and observability within a single matrix. The advantage of the proposed method is that it is computationally more efficient compared to existing gramian-based techniques since only half...... of the number of equations need to be solved in order to obtain information regarding the controllability and observability of a system compared to existing techniques. Numerical examples are provided to demonstrate the computational efficiency of the proposed method which uses frequency interval cross gramians...

  11. Altering the rest interval during high-intensity interval training does not affect muscle or performance adaptations.

    Science.gov (United States)

    Edge, Johann; Eynon, Nir; McKenna, Michael J; Goodman, Craig A; Harris, Roger C; Bishop, David J

    2013-02-01

    It has been hypothesized that exercise-induced changes in metabolites and ions are crucial in the adaptation of contracting muscle. We tested this hypothesis by comparing adaptations to two different interval-training protocols (differing only in the rest duration between intervals), which provoked different perturbations in muscle metabolites and acid-base status. Prior to and immediately after training, 12 women performed the following tests: (1) a graded exercise test to determine peak oxygen uptake (V(O2)); (2) a high-intensity exercise bout (followed 60 s later by a repeated-sprint-ability test; and (3) a repeat of the high-intensity exercise bout alone with muscle biopsies pre-exercise, immediately postexercise and after 60 s of recovery. Subjects performed 5 weeks (3 days per week) of training, with either a short (1 min; HIT-1) or a long rest period (3 min; HIT-3) between intervals; training intensity and volume were matched. Muscle [H(+)] (155 ± 15 versus 125 ± 8 nmol l(-1); P performance or muscle Na(+),K(+)-ATPase content. Following training, both groups had a significant decrease in postexercise muscle [H(+)] and lactate content, but not postexercise ATP or PCr. Postexercise PCr resynthesis increased following both training methods. In conclusion, intense interval training results in marked improvements in muscle Na(+),K(+)-ATPase content, PCr resynthesis and . However, manipulation of the rest period during intense interval training did not affect these changes.

  12. Flood control project selection using an interval type-2 entropy weight with interval type-2 fuzzy TOPSIS

    Science.gov (United States)

    Zamri, Nurnadiah; Abdullah, Lazim

    2014-06-01

    Flood control project is a complex issue which takes economic, social, environment and technical attributes into account. Selection of the best flood control project requires the consideration of conflicting quantitative and qualitative evaluation criteria. When decision-makers' judgment are under uncertainty, it is relatively difficult for them to provide exact numerical values. The interval type-2 fuzzy set (IT2FS) is a strong tool which can deal with the uncertainty case of subjective, incomplete, and vague information. Besides, it helps to solve for some situations where the information about criteria weights for alternatives is completely unknown. Therefore, this paper is adopted the information interval type-2 entropy concept into the weighting process of interval type-2 fuzzy TOPSIS. This entropy weight is believed can effectively balance the influence of uncertainty factors in evaluating attribute. Then, a modified ranking value is proposed in line with the interval type-2 entropy weight. Quantitative and qualitative factors that normally linked with flood control project are considered for ranking. Data in form of interval type-2 linguistic variables were collected from three authorised personnel of three Malaysian Government agencies. Study is considered for the whole of Malaysia. From the analysis, it shows that diversion scheme yielded the highest closeness coefficient at 0.4807. A ranking can be drawn using the magnitude of closeness coefficient. It was indicated that the diversion scheme recorded the first rank among five causes.

  13. The lucid interval associated with epidural bleeding: evolving understanding.

    Science.gov (United States)

    Ganz, Jeremy C

    2013-04-01

    The aim of this paper was to elucidate the evolution of our understanding of the term "lucid interval." A number of texts were reviewed to assess their suitability for analysis. The primary requirement was that the text contain detailed descriptions of a series of patients. Details of the clinical course, the findings and timing of surgery, and, when relevant, the time of death and postmortem findings were required. Books written by Henri-François Le Dran, Percival Pott, and James Hill fulfilled these criteria. Surgical findings included the presence and type of fractures, changes in the bone, separation of periosteum, malodorous or purulent material, tense brain, and hematoma. Postmortem findings supplemented and/or complemented the surgical findings. The courses of the patients were then tabulated, and the correlation between different clinical and operative findings was thereby determined. Our understanding of a lucid interval began in the early 18th century with the work of Henri-François Le Dran and Percival Pott in London. They did not, however, demonstrate an interval without symptoms between trauma and deterioration in patients with epidural hematomas (EDHs). The interval they described was longer than usually expected with EDHs and occurred exclusively in patients who had a posttraumatic infection. In 1751, James Hill, from Dumfries, Scotland, described the first hematoma-related lucid interval in a patient with a subdural hematoma. The first case of a lucid interval associated with an EDH was described by John Abernethy. In the 19th century, Jonathan Hutchinson and Walter Jacobson described the interval as it is known today, in cases of EDH. The most recent work on the topic came from studies in Cincinnati and Oslo, where it was demonstrated that bleeding can separate dura mater and that hemorrhage into the epidural space can be shunted out via the veins. This shunting could delay the accumulation of a hematoma and thus the rise in intracranial pressure

  14. Effects of high-intensity interval cycling performed after resistance training on muscle strength and hypertrophy.

    Science.gov (United States)

    Tsitkanou, S; Spengos, K; Stasinaki, A-N; Zaras, N; Bogdanis, G; Papadimas, G; Terzis, G

    2017-11-01

    Aim of the study was to investigate whether high-intensity interval cycling performed immediately after resistance training would inhibit muscle strength increase and hypertrophy expected from resistance training per se. Twenty-two young men were assigned into either resistance training (RE; N = 11) or resistance training plus high-intensity interval cycling (REC; N = 11). Lower body muscle strength and rate of force development (RFD), quadriceps cross-sectional area (CSA) and vastus lateralis muscle architecture, muscle fiber type composition and capillarization, and estimated aerobic capacity were evaluated before and after 8 weeks of training (2 times per week). Muscle strength and quadriceps CSA were significantly and similarly increased after both interventions. Fiber CSA increased significantly and similarly after both RE (type I: 13.6 ± 3.7%, type IIA: 17.6 ± 4.4%, type IIX: 23.2 ± 5.7%, P strength/hypertrophy after 2 months of training, while it prompts aerobic capacity and muscle capillarization. The addition of high-intensity cycling after heavy-resistance exercise may decrease RFD partly due to muscle architectural changes. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. [Penicillium-inhibiting yeasts].

    Science.gov (United States)

    Benítez Ahrendts, M R; Carrillo, L

    2004-01-01

    The objective of this work was to establish the in vitro and in vivo inhibition of post-harvest pathogenic moulds by yeasts in order to make a biocontrol product. Post-harvest pathogenic moulds Penicillium digitatum, P. italicum, P. ulaiense, Phyllosticta sp., Galactomyces geotrichum and yeasts belonging to genera Brettanomyces, Candida, Cryptococcus, Kloeckera, Pichia, Rhodotorula were isolated from citrus fruits. Some yeasts strains were also isolated from other sources. The yeasts were identified by their macro and micro-morphology and physiological tests. The in vitro and in vivo activities against P. digitatum or P. ulaiense were different. Candida cantarellii and one strain of Pichia subpelliculosa produced a significant reduction of the lesion area caused by the pathogenic moulds P. digitatum and P. ulaiense, and could be used in a biocontrol product formulation.

  16. The space of colored interval exchange transformations with flips

    International Nuclear Information System (INIS)

    Zaw, Myint

    2002-04-01

    We study the space Cr(2h, c) of c-colored exchange transformations with flips on 2h-intervals. We describe its relation to the moduli space M g,c *c of non-orientable Riemann surfaces of genus g≥0 with one boundary curve and c≥0 extra points where g=h-c-1. (author)

  17. Solving the minimum flow problem with interval bounds and flows

    Indian Academy of Sciences (India)

    ... with crisp data. In this paper, the idea of Ghiyasvand was extended for solving the minimum flow problem with interval-valued lower, upper bounds and flows. This problem can be solved using two minimum flow problems with crisp data. Then, this result is extended to networks with fuzzy lower, upper bounds and flows.

  18. Characterizing and approximating eigenvalue sets of symmetric interval matrices

    DEFF Research Database (Denmark)

    Hladík, Milan; Daney, David; Tsigaridas, Elias

    2011-01-01

    We consider the eigenvalue problem for the case where the input matrix is symmetric and its entries are perturbed, with perturbations belonging to some given intervals. We present a characterization of some of the exact boundary points, which allows us to introduce an inner approximation algorith...

  19. Begin, After, and Later: a Maximal Decidable Interval Temporal Logic

    Directory of Open Access Journals (Sweden)

    Davide Bresolin

    2010-06-01

    Full Text Available Interval temporal logics (ITLs are logics for reasoning about temporal statements expressed over intervals, i.e., periods of time. The most famous ITL studied so far is Halpern and Shoham's HS, which is the logic of the thirteen Allen's interval relations. Unfortunately, HS and most of its fragments have an undecidable satisfiability problem. This discouraged the research in this area until recently, when a number non-trivial decidable ITLs have been discovered. This paper is a contribution towards the complete classification of all different fragments of HS. We consider different combinations of the interval relations Begins, After, Later and their inverses Abar, Bbar, and Lbar. We know from previous works that the combination ABBbarAbar is decidable only when finite domains are considered (and undecidable elsewhere, and that ABBbar is decidable over the natural numbers. We extend these results by showing that decidability of ABBar can be further extended to capture the language ABBbarLbar, which lays in between ABBar and ABBbarAbar, and that turns out to be maximal w.r.t decidability over strongly discrete linear orders (e.g. finite orders, the naturals, the integers. We also prove that the proposed decision procedure is optimal with respect to the complexity class.

  20. The effects of thioridazine on the QTc interval — cardiovascular ...

    African Journals Online (AJOL)

    Background. Thioridazine has long been used as a first-line antipsychotic in South Africa without any apparent problems. Recently the American Food and Drug Administration (FDA) and Novartis have warned of potentially lethal arrhythmias that may result from the use of thioridazine. Abnormal QT-interval prolongation on ...

  1. On The Problem of Variability of Interval Data

    Czech Academy of Sciences Publication Activity Database

    Finěk, V.; Matonoha, Ctirad

    2012-01-01

    Roč. 18, č. 4 (2012), s. 76-84 ISSN 1803-9782 Grant - others:ESF(XE) CZ.1.07/2.3.00/09.0155 Institutional support: RVO:67985807 Keywords : interval data * computation of variance * theoretical analysis Subject RIV: BA - General Mathematics

  2. Assessing Post-traumatic Time Interval in Human Dry Bone

    NARCIS (Netherlands)

    de Boer, H. H. [=Hans H.; van der Merwe, A. E.; Hammer, S.; Steyn, M.; Maat, G. J. R.

    2015-01-01

    The post-traumatic status of antemortem fractures in human dry bone remains is currently defined as being either healing' or healed'. However, detailed dating' of the related post-traumatic time interval would be desirable, since it would aid in assessing individual medical status and care at the

  3. The Boundary Crossing Theorem and the Maximal Stability Interval

    Directory of Open Access Journals (Sweden)

    Jorge-Antonio López-Renteria

    2011-01-01

    useful tools in the study of the stability of family of polynomials. Although both of these theorem seem intuitively obvious, they can be used for proving important results. In this paper, we give generalizations of these two theorems and we apply such generalizations for finding the maximal stability interval.

  4. Constructing seasonally adjusted data with time-varying confidence intervals

    NARCIS (Netherlands)

    S.J. Koopman (Siem Jan); Ph.H.B.F. Franses (Philip Hans)

    2001-01-01

    textabstractSeasonal adjustment methods transform observed time series data into estimated data, where these estimated data are constructed such that they show no or almost no seasonal variation. An advantage of model-based methods is that these can provide confidence intervals around the seasonally

  5. Effect of sprint interval versus continuous cycling on postprandial lipaemia.

    Science.gov (United States)

    Tan, Min Sze; Mok, Alexander; Yap, Mei Chan; Burns, Stephen F

    2013-01-01

    The present study compares the effect of a single bout of sprint interval cycling against continuous cycling on postprandial lipaemia. Participants were nine healthy volunteers (five male), aged 20-26 years. Each participant undertook three 2-d trials in a random order. On day 1, participants rested (control), undertook a single 20 minute bout of continuous cycling at 70% of maximum oxygen uptake or completed four 30-second bouts of sprint interval cycling on a cycle ergometer, separated by 4.5 minutes of recovery. On day 2, participants rested and consumed a test meal (75% fat). Triacylglycerol concentrations were measured fasting and for 6 hours after the meal. The total area under the triacylglycerol concentration against time curve was similar among trials (mean (SD): control, 9.51 (3.50) mmol · l(-1) compared with continuous cycling, 8.58 (3.08) mmol · l(-1) compared with sprint interval cycling, 9.28 (1.89) mmol · l(-1); P = 0.517). There was no difference in the pattern of TAG response to the test meal among trials (trial × time interaction, P = 0.637). The present study found no effect of sprint interval or continuous cycling on postprandial lipaemia, with the reason for this finding unclear. Future studies need to more precisely determine the relationship between exercise and postprandial lipaemia across different types of exercise.

  6. Parametric change point estimation, testing and confidence interval ...

    African Journals Online (AJOL)

    In many applications like finance, industry and medicine, it is important to consider that the model parameters may undergo changes at unknown moment in time. This paper deals with estimation, testing and confidence interval of a change point for a univariate variable which is assumed to be normally distributed. To detect ...

  7. Calving interval genetic parameters and trends for dairy breeds in ...

    African Journals Online (AJOL)

    Calving interval (CI) is a fertility trait that can be used in selection programmes to minimize the negative effects that selection for production have on fertility. CI can be derived from milk recording data, therefore this fertility trait can easily be implemented in the National Dairy Genetic Evaluations of South Africa. The aim of this ...

  8. Ovarian follicular dynamics during the interovulatory interval in Najdi ...

    African Journals Online (AJOL)

    Results indicated the presence of either four (n = 2 estrus cycles) or five (n = 3 estrus cycles) waves of follicular growth during the interovulatory interval. Each wave was characterized by the development of at least 1 large follicle (dominant) and a variable number of small follicles (subordinate). The mean number of follicular ...

  9. Observations on the lambing interval of the cape bushbuck ...

    African Journals Online (AJOL)

    A record of births from three Cape bushbuck ewes at Queens Park Zoo, East London, from November 1971 to December 1974, indicated that the mean lambing interval of Tragelaphus scriptus sylvaticus in captivity is 249 days and that ewes reach sexual maturity at approximately one year of age.

  10. Genetic relationships between calving interval and linear type traits in

    African Journals Online (AJOL)

    Genetic correlations between first calving interval (CI) and linear type traits in South African Holstein and Jersey cattle were estimated to assess the possibility of using type information as selection criteria for CI. All linear type traits routinely evaluated under the National Genetic Evaluation Programme (18 for Jersey and 17 ...

  11. Reference interval of thyroxine and thyrotropin of healthyterm ...

    African Journals Online (AJOL)

    Objective: To establish a local Reference Interval of Serum Thyroxine (T4) and Serum Thyroid stimulating Hormone(TSH) of healthy Nigerian Newborns in Jos University Teaching Hospital Jos. Materials and Methods: One hundred and sixty healthy term Nigerian Newborns who fulfilled the criteria for inclusion were ...

  12. Integers without Large Prime Factors in Short Intervals: Conditional ...

    Indian Academy of Sciences (India)

    ... Public Lectures · Lecture Workshops · Refresher Courses · Symposia · Live Streaming. Home; Journals; Proceedings – Mathematical Sciences; Volume 120; Issue 5. Integers without Large Prime Factors in Short Intervals: Conditional Results. Goutam Pal Satadal Ganguly. Volume 120 Issue 5 November 2010 pp 515-524 ...

  13. Lactation yield: Interval level comparison of milk records for genetic ...

    African Journals Online (AJOL)

    1220 records ... Lactation yield: Interval level comparison of milk records for genetic improvement in Friesian vs Arsi crossbred cows in the highlands of south eastern. Ethiopia. Dumar Wabe1 and Kassahun Asmare2. 1Allage Agricultural Technical, Vocational Education Training College, P.O. Box 077. 2School of Veterinary ...

  14. Time Interval to Initiation of Contraceptive Methods Following ...

    African Journals Online (AJOL)

    Objectives: The objectives of the study were to determine factors affecting the interval between a woman's last childbirth and the initiation of contraception. Materials and Methods: This was a retrospective study. Family planning clinic records of the Barau Dikko Teaching Hospital Kaduna from January 2000 to March 2014 ...

  15. QT interval changes in term pregnant women living at moderately ...

    African Journals Online (AJOL)

    Objective: This study aimed to compare the QT interval changes in women with term pregnancy living at moderately high altitude (1890 m in Erzurum, Turkey) with those of women living at sea level (31 m in İstanbul, Turkey). Materials and Methods: One‑hundred ten women (n = 55, for each group) with full‑term and single ...

  16. Prognostic Significance Of QT Interval Prolongation In Adult ...

    African Journals Online (AJOL)

    Prognostic survival studies for heart-rate corrected QT interval in patients with chronic heart failure are few; although these patients are known to have a high risk of sudden cardiac death. This study was aimed at determining the mortality risk associated with prolonged QTc in Nigerians with heart failure. Ninety-six ...

  17. Delayed interval delivery in twin pregnancy without cerclage: Case ...

    African Journals Online (AJOL)

    After the loss of the first foetus, delayed delivery in multiple pregnancies can be successful in selected cases as exemplified by the case presentation. In well prepared perinatal centers, with physically and psychologically balanced patients who are well informed about the risks and benefits of the procedure, delayed interval ...

  18. Quantifying uncertainty on sediment loads using bootstrap confidence intervals

    Science.gov (United States)

    Slaets, Johanna I. F.; Piepho, Hans-Peter; Schmitter, Petra; Hilger, Thomas; Cadisch, Georg

    2017-01-01

    Load estimates are more informative than constituent concentrations alone, as they allow quantification of on- and off-site impacts of environmental processes concerning pollutants, nutrients and sediment, such as soil fertility loss, reservoir sedimentation and irrigation channel siltation. While statistical models used to predict constituent concentrations have been developed considerably over the last few years, measures of uncertainty on constituent loads are rarely reported. Loads are the product of two predictions, constituent concentration and discharge, integrated over a time period, which does not make it straightforward to produce a standard error or a confidence interval. In this paper, a linear mixed model is used to estimate sediment concentrations. A bootstrap method is then developed that accounts for the uncertainty in the concentration and discharge predictions, allowing temporal correlation in the constituent data, and can be used when data transformations are required. The method was tested for a small watershed in Northwest Vietnam for the period 2010-2011. The results showed that confidence intervals were asymmetric, with the highest uncertainty in the upper limit, and that a load of 6262 Mg year-1 had a 95 % confidence interval of (4331, 12 267) in 2010 and a load of 5543 Mg an interval of (3593, 8975) in 2011. Additionally, the approach demonstrated that direct estimates from the data were biased downwards compared to bootstrap median estimates. These results imply that constituent loads predicted from regression-type water quality models could frequently be underestimating sediment yields and their environmental impact.

  19. Non-Guard Interval based and Genetic Algorithm Assisted ...

    African Journals Online (AJOL)

    -GA) scheme was proposed for direct sequence ultra wideband (DS-UWB) wireless communication systems. The proposed FDE-GA scheme does not require a guard interval (GI) and the output of the RAKE receiver is used as the input to our ...

  20. Approximation by Müntz spaces on positive intervals

    KAUST Repository

    Ait-Haddou, Rachid

    2013-11-01

    The so-called Bernstein operators were introduced by S.N. Bernstein in 1912 to give a constructive proof of Weierstrass\\' theorem. We show how to extend his result to Müntz spaces on positive intervals. © 2013 Académie des sciences.

  1. Establishment of hormone reference intervals for infants born gestation.

    Science.gov (United States)

    Greaves, Ronda F; Zacharin, Margaret R; Donath, Susan M; Inder, Terrie E; Doyle, Lex W; Hunt, Rodney W

    2014-10-01

    Preterm infants, especially those born very preterm (gestation), suffer a number of morbidities. Immaturity of the endocrine system and its potential impact on morbidity is the subject of numerous studies. Hormone concentrations are sometimes measured in very preterm infants, however there are little normative data available to be able to interpret the results. The aim of this study was to describe age appropriate hormone reference intervals for babies born less than 30 weeks' gestation. Samples were collected at 1, 4, 7, 14, 21, 28 and 42 days after birth from babies born 23-29 weeks' gestation. The serum was analyzed for seven hormones by automated chemiluminescent immunoassay (Siemens Immulite 2000). Results from the 107 infants who survived beyond 40 weeks' corrected gestational age were included in the data analysis. Cortisol, dehydroepiandrosterone sulfate, growth hormone and progesterone levels were highest during the first seven days with levels up to 10,801nmol/L; 26.6μmol/L; 343mU/L; and >63.6nmol/L respectively. Free thyroxine levels were as low as established as the levels were below the analyzer's sensitivity. There were no differences in reference intervals between male and female infants. We describe gestation appropriate reference intervals for six hormones measured in babies born gestation. Utilization of these reference intervals permits the correct and timely interpretation of results to the clinician. Copyright © 2014 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  2. Interval Routing and Minor-Monotone Graph Parameters

    NARCIS (Netherlands)

    Bakker, E.M.; Bodlaender, H.L.; Tan, R.B.; Leeuwen, J. van

    2006-01-01

    We survey a number of minor-monotone graph parameters and their relationship to the complexity of routing on graphs. In particular we compare the interval routing parameters κslir(G) and κsir(G) with Colin de Verdi`ere’s graph invariant μ(G) and its variants λ(G) and κ(G). We show that for all the

  3. A quick method to calculate QTL confidence interval

    Indian Academy of Sciences (India)

    2011-08-19

    Aug 19, 2011 ... strap sample form the bootstrap distribution of QTL location. The 2.5 and 97.5 percentiles are lower limit and upper limit of 95% QTL confidence interval. Although bootstrap is time- demanding, especially for large complex populations, it has been used frequently. Some authors' investigation showed.

  4. Bootstrap confidence intervals for three-way methods

    NARCIS (Netherlands)

    Kiers, Henk A.L.

    Results from exploratory three-way analysis techniques such as CANDECOMP/PARAFAC and Tucker3 analysis are usually presented without giving insight into uncertainties due to sampling. Here a bootstrap procedure is proposed that produces percentile intervals for all output parameters. Special

  5. Effect of interval training programme on pulse pressure in the ...

    African Journals Online (AJOL)

    EB

    2013-09-03

    Sep 3, 2013 ... Abstract. Background: Pulse pressure (PP), might be a stronger determinants of cardiovascular risk. Objective: To investigate the effect of interval training program on PP in subjects with hypertension. Methods: Two hundred and forty five male patients with mild to moderate (Systolic Blood Pressure [SBP] ...

  6. Effect of interval training programme on pulse pressure in the ...

    African Journals Online (AJOL)

    Background: Pulse pressure (PP), might be a stronger determinants of cardiovascular risk. Objective: To investigate the effect of interval training program on PP in subjects with hypertension. Methods: Two hundred and forty five male patients with mild to moderate (Systolic Blood Pressure [SBP] between 140-179 & Diastolic ...

  7. Effects of Interval Training Programme on Resting Heart Rate in ...

    African Journals Online (AJOL)

    DATONYE ALASIA

    4 and Department of Radiology,Federal Medical Center, Owerri, Nigeria. ABSTRACT. Background: Heart rate (HR) is a determinant of cardiovascular event risk in patient with hypertension. The primary purpose of the present study was to investigate the effect of interval training program on HR in black African subjects with.

  8. High-Intensity Interval Training for Improving Postprandial Hyperglycemia

    Science.gov (United States)

    Little, Jonathan P.; Francois, Monique E.

    2014-01-01

    High-intensity interval training (HIIT) has garnered attention in recent years as a time-efficient exercise option for improving cardiovascular and metabolic health. New research demonstrates that HIIT may be particularly effective for improving postprandial hyperglycemia in individuals with, or at risk for, type 2 diabetes (T2D). These findings…

  9. Heartbeat Classification Using Normalized RR Intervals and Morphological Features

    Directory of Open Access Journals (Sweden)

    Chun-Cheng Lin

    2014-01-01

    Full Text Available This study developed an automatic heartbeat classification system for identifying normal beats, supraventricular ectopic beats, and ventricular ectopic beats based on normalized RR intervals and morphological features. The proposed heartbeat classification system consists of signal preprocessing, feature extraction, and linear discriminant classification. First, the signal preprocessing removed the high-frequency noise and baseline drift of the original ECG signal. Then the feature extraction derived the normalized RR intervals and two types of morphological features using wavelet analysis and linear prediction modeling. Finally, the linear discriminant classifier combined the extracted features to classify heartbeats. A total of 99,827 heartbeats obtained from the MIT-BIH Arrhythmia Database were divided into three datasets for the training and testing of the optimized heartbeat classification system. The study results demonstrate that the use of the normalized RR interval features greatly improves the positive predictive accuracy of identifying the normal heartbeats and the sensitivity for identifying the supraventricular ectopic heartbeats in comparison with the use of the nonnormalized RR interval features. In addition, the combination of the wavelet and linear prediction morphological features has higher global performance than only using the wavelet features or the linear prediction features.

  10. Interval change analysis to improve computer aided detection in mammography.

    NARCIS (Netherlands)

    Timp, S.; Karssemeijer, N.

    2006-01-01

    We are developing computer aided diagnosis (CAD) techniques to study interval changes between two consecutive mammographic screening rounds. We have previously developed methods for the detection of malignant masses based on features extracted from single mammographic views. The goal of the present

  11. The Behavioral Economics of Choice and Interval Timing

    Science.gov (United States)

    Jozefowiez, J.; Staddon, J. E. R.; Cerutti, D. T.

    2009-01-01

    The authors propose a simple behavioral economic model (BEM) describing how reinforcement and interval timing interact. The model assumes a Weber-law-compliant logarithmic representation of time. Associated with each represented time value are the payoffs that have been obtained for each possible response. At a given real time, the response with…

  12. Music enhances performance and perceived enjoyment of sprint interval exercise.

    Science.gov (United States)

    Stork, Matthew J; Kwan, Matthew Y W; Gibala, Martin J; Martin Ginis, Kathleen A

    2015-05-01

    Interval exercise training can elicit physiological adaptations similar to those of traditional endurance training, but with reduced time. However, the intense nature of specific protocols, particularly the "all-out" efforts characteristic of sprint interval training (SIT), may be perceived as being aversive. The purpose of this study was to determine whether listening to self-selected music can reduce the potential aversiveness of an acute session of SIT by improving affect, motivation, and enjoyment, and to examine the effects of music on performance. Twenty moderately active adults (22 ± 4 yr) unfamiliar with interval exercise completed an acute session of SIT under two different conditions: music and no music. The exercise consisted of four 30-s "all-out" Wingate Anaerobic Test bouts on a cycle ergometer, separated by 4 min of rest. Peak and mean power output, RPE, affect, task motivation, and perceived enjoyment of the exercise were measured. Mixed-effects models were used to evaluate changes in dependent measures over time and between the two conditions. Peak and mean power over the course of the exercise session were higher in the music condition (coefficient = 49.72 [SE = 13.55] and coefficient = 23.65 [SE = 11.30]; P music condition (coefficient = 7.00 [SE = 3.05]; P Music enhances in-task performance and enjoyment of an acute bout of SIT. Listening to music during intense interval exercise may be an effective strategy for facilitating participation in, and adherence to, this form of training.

  13. Non-Guard Interval based and Genetic Algorithm Assisted ...

    African Journals Online (AJOL)

    USER

    ABSTRACT: In this work, a genetic algorithm (GA) based frequency domain equalization (FDE-GA) scheme was proposed for direct sequence ultra wideband (DS-UWB) wireless communication systems. The proposed FDE-GA scheme does not require a guard interval (GI) and the output of the RAKE receiver is used as the ...

  14. Integers without large prime factors in short intervals: Conditional ...

    Indian Academy of Sciences (India)

    ... Public Lectures · Lecture Workshops · Refresher Courses · Symposia · Live Streaming. Home; Journals; Proceedings – Mathematical Sciences; Volume 120; Issue 5. Integers without Large Prime Factors in Short Intervals: Conditional Results. Goutam Pal Satadal Ganguly. Volume 120 Issue 5 November 2010 pp 515-524 ...

  15. Using confidence intervals for assessing reliability of real tests

    NARCIS (Netherlands)

    Oosterwijk, P.R.; van der Ark, L.A.; Sijtsma, K.

    2018-01-01

    Test authors report sample reliability values but rarely consider the sampling error and related confidence intervals. This study investigated the truth of this conjecture for 116 tests with 1,024 reliability estimates (105 pertaining to test batteries and 919 to tests measuring a single attribute)

  16. Time intervals in diagnosing Parkinson's disease: The patients' views

    NARCIS (Netherlands)

    Plouvier, A.O.A.; Olde Hartman, T.C.; Boots, L.P.; Bloem, B.R.; Weel, C. van; Lagro-Janssen, A.L.M.

    2015-01-01

    OBJECTIVE: To explore patients' views on their pathway to the diagnosis of Parkinson's disease (PD). METHODS: A qualitative study of 52 essays written by patients with PD, using comparative content analysis. RESULTS: Patients divide their diagnostic pathway into three time intervals: recognition of

  17. Interval algebra: an effective means of scheduling surveillance radar networks

    CSIR Research Space (South Africa)

    Focke, RW

    2015-05-01

    Full Text Available Interval Algebra provides an effective means to schedule surveillance radar networks, as it is a temporal ordering constraint language. Thus it provides a solution to a part of resource management, which is included in the revised Data Fusion...

  18. delayed interval delivery in twin pregnancy without cerclage

    African Journals Online (AJOL)

    2011-11-11

    Nov 11, 2011 ... the procedure, delayed interval delivery in twin pregnancy without cerclage may be a reasonable strategy. REFERENCES. Livingston, J. C., Livingston, L. W., Ramsey, R. and Sibai,. 1. B. M. Second-Trimester Asynchronous Multifetal Delivery. Results in Poor Perinatal Outcome. Obstetrics & Gynecol. 2004 ...

  19. Coordinates and intervals in graph-based reference genomes.

    Science.gov (United States)

    Rand, Knut D; Grytten, Ivar; Nederbragt, Alexander J; Storvik, Geir O; Glad, Ingrid K; Sandve, Geir K

    2017-05-18

    It has been proposed that future reference genomes should be graph structures in order to better represent the sequence diversity present in a species. However, there is currently no standard method to represent genomic intervals, such as the positions of genes or transcription factor binding sites, on graph-based reference genomes. We formalize offset-based coordinate systems on graph-based reference genomes and introduce methods for representing intervals on these reference structures. We show the advantage of our methods by representing genes on a graph-based representation of the newest assembly of the human genome (GRCh38) and its alternative loci for regions that are highly variable. More complex reference genomes, containing alternative loci, require methods to represent genomic data on these structures. Our proposed notation for genomic intervals makes it possible to fully utilize the alternative loci of the GRCh38 assembly and potential future graph-based reference genomes. We have made a Python package for representing such intervals on offset-based coordinate systems, available at https://github.com/uio-cels/offsetbasedgraph . An interactive web-tool using this Python package to visualize genes on a graph created from GRCh38 is available at https://github.com/uio-cels/genomicgraphcoords .

  20. Positive solutions and eigenvalue intervals for nonlinear systems

    Indian Academy of Sciences (India)

    12]. In this paper, we will show how our method allows to improve the range of eigenvalue intervals. The new results are easily derived from a general result, stated as Theorem 3.1, which gives sufficient conditions to guarantee the existence of ...

  1. Cardiac Time Intervals by Tissue Doppler Imaging M-Mode

    DEFF Research Database (Denmark)

    Biering-Sørensen, Tor; Mogelvang, Rasmus; de Knegt, Martina Chantal

    2016-01-01

    PURPOSE: To define normal values of the cardiac time intervals obtained by tissue Doppler imaging (TDI) M-mode through the mitral valve (MV). Furthermore, to evaluate the association of the myocardial performance index (MPI) obtained by TDI M-mode (MPITDI) and the conventional method of obtaining...

  2. Solving the minimum flow problem with interval bounds and flows

    Indian Academy of Sciences (India)

    and Ciurea et al (2008b) solved the minimum flow problem for bipartite networks, and Ciurea. & Deaconu (2007) solved the ... In Ghiyasvand (2011), a new method to solve the minimum cost flow problem with interval .... multiplication of convex sets, when the fuzzification uses Definition 1 for max–min and order operations.

  3. A note on regularity and positive definiteness of interval matrices

    Czech Academy of Sciences Publication Activity Database

    Farhadsefat, R.; Lotfi, T.; Rohn, Jiří

    2012-01-01

    Roč. 10, č. 1 (2012), s. 322-328 ISSN 1895-1074 Institutional research plan: CEZ:AV0Z10300504 Keywords : interval matrix * regularity condition * positive definiteness Subject RIV: BA - General Mathematics Impact factor: 0.405, year: 2012

  4. Time Interval to Initiation of Contraceptive Methods Following ...

    African Journals Online (AJOL)

    2018-01-30

    Jan 30, 2018 ... Objectives: The objectives of the study were to determine factors affecting the interval between a woman's last childbirth and the initiation of contraception. Materials and Methods: This was a retrospective study. Family planning clinic records of the Barau Dikko Teaching Hospital Kaduna from January 2000 ...

  5. The Relationship Between QT Intervals and Cardiac Autonomic ...

    African Journals Online (AJOL)

    To study the pattern of QT intervals in Type 2 diabetic patients (T2DM) and investigate whether they have correlation with or predict development of Cardiac Autonomic Neuropathy (CAN). One hundred and eight (108) T2DM patients were compared with 88 normal controls. They all had resting ECG performed and QT ...

  6. Effects Of Cutting Interval On The Feed Value Of Enterolobium ...

    African Journals Online (AJOL)

    The effects of cutting interval on the rumen DM degradation and CP and NDF contents of Enterolobium cyclocarpum leaves was determined. The trees were cut every 6, 9 and 12 weeks at 50 cm above ground level. Leaf samples taken at the ends of the major and minor wet seasons were incubated for 3, 6, 12, 24, 72 and ...

  7. Mnemonic benefits of retrieval practice at short retention intervals.

    Science.gov (United States)

    Rowland, Christopher A; DeLosh, Edward L

    2015-01-01

    The testing effect refers to the retention benefit conferred by prior retrieval of information from memory. Although the testing effect is a robust phenomenon, a common assumption is that reliable memory benefits only emerge after long retention intervals of days or weeks. The present study focused on potential test-induced retention benefits for brief retention intervals on the order of minutes and tens of seconds. Participants in four experiments studied lists of words. Some of the items were subjected to an initial cued recall test, and others were re-presented for additional study. Free recall tests were administered in each experiment following retention intervals ranging from 30 s to 8 min. When initial retrieval practice was successful (Experiments 1 through 3), or feedback compensated for unsuccessful retrieval (Experiment 4), significant testing effects emerged at all retention intervals. Results are discussed in the context of a bifurcated item-distribution model and highlight the importance of initial test performance and the type of analysis employed when examining testing effect data.

  8. Effect of recombinant bovine somatotropin application intervals on ...

    African Journals Online (AJOL)

    The aim of this study was to evaluate the effect of recombinant bovine somatotropin (rBST) application intervals on chemical composition of milk from Girolando cows with productivity below 20 L/milk/day and animals with productivity above 20.1 liters/milk/day. The study included 30 Girolando cows with production ranging ...

  9. Confidence Intervals for Assessing Heterogeneity in Generalized Linear Mixed Models

    Science.gov (United States)

    Wagler, Amy E.

    2014-01-01

    Generalized linear mixed models are frequently applied to data with clustered categorical outcomes. The effect of clustering on the response is often difficult to practically assess partly because it is reported on a scale on which comparisons with regression parameters are difficult to make. This article proposes confidence intervals for…

  10. Some simple applications of probability models to birth intervals

    International Nuclear Information System (INIS)

    Shrestha, G.

    1987-07-01

    An attempt has been made in this paper to apply some simple probability models to birth intervals under the assumption of constant fecundability and varying fecundability among women. The parameters of the probability models are estimated by using the method of moments and the method of maximum likelihood. (author). 9 refs, 2 tabs

  11. Self-pacing in interval training: a teleoanticipatory approach.

    Science.gov (United States)

    Edwards, Andrew M; Bentley, Maria B; Mann, Michael E; Seaholme, Timothy S

    2011-01-01

    The aim of the present study was to investigate whether the concurrent use of Rating of Perceived Exertion (RPE) and a new Perceived Readiness (PR) scale facilitates optimal interval training performance outcomes. Eleven competitive male runners completed outdoor interval track-running trials at a pre-set RPE. The PR scale was used to facilitate self-determined recovery, while minimum heart rate (HR) and work to rest ratio (WR) strategies were used as comparative conditions. Duplicate PR trial performances were similar but intercondition comparisons identified that the HR trial was significantly slower than both WR and PR conditions. There was no difference in performance between WR and PR, but recoveries for both PR trials were significantly shorter than for WR. Since the aim of interval training is to sustain performance with the shortest possible recovery time, the concurrent use of RPE and PR scales appears to be a useful psychophysiological technique to self- determine both work and rest in interval training. Copyright © 2010 Society for Psychophysiological Research.

  12. Correlates of emergency response interval and mortality from ...

    African Journals Online (AJOL)

    A retrospective study to determine the influence of blood transfusion emergency response interval on Mortality from childhood severe anemia was carried out. An admission record of all children with severe anemia over a 5-year period was reviewed. Those who either died before transfusion or got discharged against ...

  13. Time-variant random interval natural frequency analysis of structures

    Science.gov (United States)

    Wu, Binhua; Wu, Di; Gao, Wei; Song, Chongmin

    2018-02-01

    This paper presents a new robust method namely, unified interval Chebyshev-based random perturbation method, to tackle hybrid random interval structural natural frequency problem. In the proposed approach, random perturbation method is implemented to furnish the statistical features (i.e., mean and standard deviation) and Chebyshev surrogate model strategy is incorporated to formulate the statistical information of natural frequency with regards to the interval inputs. The comprehensive analysis framework combines the superiority of both methods in a way that computational cost is dramatically reduced. This presented method is thus capable of investigating the day-to-day based time-variant natural frequency of structures accurately and efficiently under concrete intrinsic creep effect with probabilistic and interval uncertain variables. The extreme bounds of the mean and standard deviation of natural frequency are captured through the embedded optimization strategy within the analysis procedure. Three particularly motivated numerical examples with progressive relationship in perspective of both structure type and uncertainty variables are demonstrated to justify the computational applicability, accuracy and efficiency of the proposed method.

  14. On the Recognition of Fuzzy Circular Interval Graphs

    OpenAIRE

    Oriolo, Gianpaolo; Pietropaoli, Ugo; Stauffer, Gautier

    2011-01-01

    Fuzzy circular interval graphs are a generalization of proper circular arc graphs and have been recently introduced by Chudnovsky and Seymour as a fundamental subclass of claw-free graphs. In this paper, we provide a polynomial-time algorithm for recognizing such graphs, and more importantly for building a suitable representation.

  15. Constructing Approximate Confidence Intervals for Parameters with Structural Equation Models

    Science.gov (United States)

    Cheung, Mike W. -L.

    2009-01-01

    Confidence intervals (CIs) for parameters are usually constructed based on the estimated standard errors. These are known as Wald CIs. This article argues that likelihood-based CIs (CIs based on likelihood ratio statistics) are often preferred to Wald CIs. It shows how the likelihood-based CIs and the Wald CIs for many statistics and psychometric…

  16. Likelihood-Based Confidence Intervals in Exploratory Factor Analysis

    NARCIS (Netherlands)

    Oort, Frans J.

    2011-01-01

    In exploratory or unrestricted factor analysis, all factor loadings are free to be estimated. In oblique solutions, the correlations between common factors are free to be estimated as well. The purpose of this article is to show how likelihood-based confidence intervals can be obtained for rotated

  17. Likelihood-based confidence intervals in exploratory factor analysis

    NARCIS (Netherlands)

    Oort, F.J.

    2011-01-01

    In exploratory or unrestricted factor analysis, all factor loadings are free to be estimated. In oblique solutions, the correlations between common factors are free to be estimated as well. The purpose of this article is to show how likelihood-based confidence intervals can be obtained for rotated

  18. Likelihood-Based Confidence Intervals in Exploratory Factor Analysis

    Science.gov (United States)

    Oort, Frans J.

    2011-01-01

    In exploratory or unrestricted factor analysis, all factor loadings are free to be estimated. In oblique solutions, the correlations between common factors are free to be estimated as well. The purpose of this article is to show how likelihood-based confidence intervals can be obtained for rotated factor loadings and factor correlations, by…

  19. Interval endurance capacity of talented youth soccer players

    NARCIS (Netherlands)

    Visscher, C; Elferink-Gemser, MT; Lemmink, KAPM

    The purpose of this study, in which 113 talented Youth soccer players (M = 16.0 yr., SD = 15), selected by their age and level of performance participated, was to investigate interval endurance capacity needed to play at the highest level of competition in the age-category 12 through 18.

  20. Predicting restoration of kidney function during CRRT-free intervals

    Directory of Open Access Journals (Sweden)

    Heise Daniel

    2012-01-01

    Full Text Available Abstract Background Renal failure is common in critically ill patients and frequently requires continuous renal replacement therapy (CRRT. CRRT is discontinued at regular intervals for routine changes of the disposable equipment or for replacing clogged filter membrane assemblies. The present study was conducted to determine if the necessity to continue CRRT could be predicted during the CRRT-free period. Materials and methods In the period from 2003 to 2006, 605 patients were treated with CRRT in our ICU. A total of 222 patients with 448 CRRT-free intervals had complete data sets and were used for analysis. Of the total CRRT-free periods, 225 served as an evaluation group. Twenty-nine parameters with an assumed influence on kidney function were analyzed with regard to their potential to predict the restoration of kidney function during the CRRT-free interval. Using univariate analysis and logistic regression, a prospective index was developed and validated in the remaining 223 CRRT-free periods to establish its prognostic strength. Results Only three parameters showed an independent influence on the restoration of kidney function during CRRT-free intervals: the number of previous CRRT cycles (medians in the two outcome groups: 1 vs. 2, the "Sequential Organ Failure Assessment"-score (means in the two outcome groups: 8.3 vs. 9.2 and urinary output after the cessation of CRRT (medians in two outcome groups: 66 ml/h vs. 10 ml/h. The prognostic index, which was calculated from these three variables, showed a satisfactory potential to predict the kidney function during the CRRT-free intervals; Receiver operating characteristic (ROC analysis revealed an area under the curve of 0.798. Conclusion Restoration of kidney function during CRRT-free periods can be predicted with an index calculated from three variables. Prospective trials in other hospitals must clarify whether our results are generally transferable to other patient populations.

  1. Withdrawal of voluntary inhibition unravels the off state of the spontaneous blink generator.

    Science.gov (United States)

    Moraitis, Timoleon; Ghosh, Arko

    2014-12-01

    Involuntary movements such as spontaneous eye blinks can be successfully inhibited at will. Little do we know how the voluntary motor circuits countermand spontaneous blinks. Do the voluntary inhibitory commands act to pause or to turn off the endogenous blink generator, or does inhibition intersect and counter the generator׳s excitatory outputs? In theory, the time taken for the system to generate an after-inhibition blink will reflect onto the form of inhibition. For instance, if voluntary commands were to turn the blink generator off then the after-blink latency would be fixed to the inhibition offset and reflect the time it takes for the generator to rebound and turn on. In this study we measured the after-blink latency from the offset of voluntary inhibition. Volunteers inhibited their blinks in response to sound tones of randomly varying durations. At the offset volunteers withdrew the inhibition and relaxed. Interestingly, the spontaneous after-blinks were fixed to the offset of the inhibition as if the generator rebounded from an off state. The after-blink latency was not related to the duration of the inhibition, and inhibiting even for a small fraction of the mean inter-blink interval generated an after-blink time-locked to the inhibition offset. Interestingly, the insertion of voluntary blinks after inhibition further altered the blink generator by delaying the spontaneous after-blinks. We propose that the inhibition of spontaneous blinks at the level of the generator allows for highly effective voluntary countermanding. Nevertheless, the withdrawal of such inhibition was strongly associated with motor excitation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Effects of decreased inhibition on synaptic plasticity and dendritic morphology in the juvenile prefrontal cortex

    Directory of Open Access Journals (Sweden)

    Xanthippi Konstantoudaki

    2014-03-01

    , we tested whether synaptic plasticity properties of intra-cortical layer II synapses are affected. In adult control mice, tetanic stimulation results in long-term potentiation that lasts at least 50 min (Konstantoudaki et al, 2013. In control mice of the age tested in this study (PD 20-30, LTP could not be induced with the same stimulation. However, we find that Rac1 KO mice do express long-term potentiation. We next studied the dendritic morphology of layer II neurons in the prefrontal cortex, in an effort to identify the mechanism by which Rac1 KO mice exhibit LTP, while the control mice of the same age do not. For this, we stained mouse brains of Rac1 KO and Rac1 heterozygous mice with the Golgi-Cox method. We analyzed the number of secondary apical dendrites, their thickness, as well as the number of spines. We find that the dendrites of pyramidal neurons of Rac1 KO mice have decreased thickness and increased number of spines compared to pyramidal neurons from Rac1 heterozygous mice. These findings could also provide a mechanistic explanation for the presence of LTP in Rac1 KO mice. In conclusion, we find that decreased inhibition during development alters the morphological and functional characteristics of pyramidal neurons in layer II prefrontal cortex of mice. These alterations could provide a cellular substrate for emotional and cognitive dysfunctions present in these mice (Konstantoudaki et al, 2012.

  3. QT Interval Variability Index and QT Interval Duration in Different Sleep Stages: Analysis of Polysomnographic Recordings in Nonapneic Male Patients

    Directory of Open Access Journals (Sweden)

    Moonika Viigimae

    2015-01-01

    Full Text Available The aim of the study was to determine whether different sleep stages, especially REM sleep, affect QT interval duration and variability in male patients without obstructive sleep apnea (OSA. Polysomnographic recordings of 30 patients were analyzed. Beat-to-beat QT interval variability was calculated using QTV index (QTVI formula. For QTc interval calculation, in addition to Bazett’s formula, linear and parabolic heart rate correction formulas with two separate α values were used. QTVI and QTc values were calculated as means of 2 awake, 3 NREM, and 3 REM sleep episodes; the duration of each episode was 300 sec. Mean QTVI values were not statistically different between sleep stages. Therefore, elevated QTVI values found in patients with OSA cannot be interpreted as physiological sympathetic impact during REM sleep and should be considered as a risk factor for potentially life-threatening ventricular arrhythmias. The absence of difference of the mean QTc interval values between NREM and REM stages seems to confirm our conclusion that sympathetic surges during REM stage do not induce repolarization variability. In patients without notable structural and electrical remodeling of myocardium, physiological elevation in sympathetic activity during REM sleep remains subthreshold concerning clinically significant increase of myocardial electrical instability.

  4. Recruitment and representativeness of blood donors in the INTERVAL randomised trial assessing varying inter-donation intervals.

    Science.gov (United States)

    Moore, Carmel; Bolton, Thomas; Walker, Matthew; Kaptoge, Stephen; Allen, David; Daynes, Michael; Mehenny, Susan; Sambrook, Jennifer; Watkins, Nicholas A; Miflin, Gail; Di Angelantonio, Emanuele; Ouwehand, Willem H; Roberts, David J; Danesh, John; Thompson, Simon G

    2016-09-20

    The interpretation of trial results can be helped by understanding how generalisable they are to the target population for which inferences are intended. INTERVAL, a large pragmatic randomised trial of blood donors in England, is assessing the effectiveness and safety of reducing inter-donation intervals. The trial recruited mainly from the blood service's static centres, which collect only about 10 % of whole-blood donations. Hence, the extent to which the trial's participants are representative of the general blood donor population is uncertain. We compare these groups in detail. We present the CONSORT flowchart from participant invitation to randomisation in INTERVAL. We compare the characteristics of those eligible and consenting to participate in INTERVAL with the general donor population, using the national blood supply 'PULSE' database for the period of recruitment. We compare the characteristics of specific groups of trial participants recruited from different sources, as well as those who were randomised versus those not randomised. From a total of 540,459 invitations, 48,725 donors were eligible and consented to participate in INTERVAL. The proportion of such donors varied from 1-22 % depending on the source of recruitment. The characteristics of those consenting were similar to those of the general population of 1.3 million donors in terms of ethnicity, blood group distribution and recent deferral rates from blood donation due to low haemoglobin. However, INTERVAL participants included more men (50 % versus 44 %), were slightly older (mean age 43.1 versus 42.3 years), included fewer new donors (3 % versus 22 %) and had given more donations over the previous 2 years (mean 3.3 versus 2.2) than the general donor population. Of the consenting participants, 45,263 (93 %) donors were randomised. Compared to those not randomised, the randomised donors showed qualitatively similar differences to those described above. There was broad similarity of

  5. Chaoticity of interval self-maps with positive entropy

    International Nuclear Information System (INIS)

    Xiong Jincheng.

    1988-12-01

    Li and Yorke originally introduced the notion of chaos for continuous self-map of the interval I = (0,1). In the present paper we show that an interval self-map with positive topological entropy has a chaoticity more complicated than the chaoticity in the sense of Li and Yorke. The main result is that if f:I → I is continuous and has a periodic point with odd period > 1 then there exists a closed subset K of I invariant with respect to f such that the periodic points are dense in K, the periods of periodic points in K form an infinite set and f|K is topologically mixing. (author). 9 refs

  6. Computing connection coefficients of compactly supported wavelets on bounded intervals

    Energy Technology Data Exchange (ETDEWEB)

    Romine, C.H.; Peyton, B.W.

    1997-04-01

    Daubechies wavelet basis functions have many properties that make them desirable as a basis for a Galerkin approach to solving PDEs: they are orthogonal, with compact support, and their connection coefficients can be computed. The method developed by Latto et al. to compute connection coefficients does not provide the correct inner product near the endpoints of a bounded interval, making the implementation of boundary conditions problematic. Moreover, the highly oscillatory nature of the wavelet basis functions makes standard numerical quadrature of integrals near the boundary impractical. The authors extend the method of Latto et al. to construct and solve a linear system of equations whose solution provides the exact computation of the integrals at the boundaries. As a consequence, they provide the correct inner product for wavelet basis functions on a bounded interval.

  7. Parameter identification for structural dynamics based on interval analysis algorithm

    Science.gov (United States)

    Yang, Chen; Lu, Zixing; Yang, Zhenyu; Liang, Ke

    2018-04-01

    A parameter identification method using interval analysis algorithm for structural dynamics is presented in this paper. The proposed uncertain identification method is investigated by using central difference method and ARMA system. With the help of the fixed memory least square method and matrix inverse lemma, a set-membership identification technology is applied to obtain the best estimation of the identified parameters in a tight and accurate region. To overcome the lack of insufficient statistical description of the uncertain parameters, this paper treats uncertainties as non-probabilistic intervals. As long as we know the bounds of uncertainties, this algorithm can obtain not only the center estimations of parameters, but also the bounds of errors. To improve the efficiency of the proposed method, a time-saving algorithm is presented by recursive formula. At last, to verify the accuracy of the proposed method, two numerical examples are applied and evaluated by three identification criteria respectively.

  8. Integral equations with difference kernels on finite intervals

    CERN Document Server

    Sakhnovich, Lev A

    2015-01-01

    This book focuses on solving integral equations with difference kernels on finite intervals. The corresponding problem on the semiaxis was previously solved by N. Wiener–E. Hopf and by M.G. Krein. The problem on finite intervals, though significantly more difficult, may be solved using our method of operator identities. This method is also actively employed in inverse spectral problems, operator factorization and nonlinear integral equations. Applications of the obtained results to optimal synthesis, light scattering, diffraction, and hydrodynamics problems are discussed in this book, which also describes how the theory of operators with difference kernels is applied to stable processes and used to solve the famous M. Kac problems on stable processes. In this second edition these results are extensively generalized and include the case of all Levy processes. We present the convolution expression for the well-known Ito formula of the generator operator, a convolution expression that has proven to be fruitful...

  9. Process control and optimization with simple interval calculation method

    DEFF Research Database (Denmark)

    Pomerantsev, A.; Rodionova, O.; Høskuldsson, Agnar

    2006-01-01

    for the quality improvement in the course of production. The latter is an active quality optimization, which takes into account the actual history of the process. The advocate approach is allied to the conventional method of multivariate statistical process control (MSPC) as it also employs the historical process......Methods of process control and optimization are presented and illustrated with a real world example. The optimization methods are based on the PLS block modeling as well as on the simple interval calculation methods of interval prediction and object status classification. It is proposed to employ...... the series of expanding PLS/SIC models in order to support the on-line process improvements. This method helps to predict the effect of planned actions on the product quality and thus enables passive quality control. We have also considered an optimization approach that proposes the correcting actions...

  10. Computation of robustly stabilizing PID controllers for interval systems.

    Science.gov (United States)

    Matušů, Radek; Prokop, Roman

    2016-01-01

    The paper is focused on the computation of all possible robustly stabilizing Proportional-Integral-Derivative (PID) controllers for plants with interval uncertainty. The main idea of the proposed method is based on Tan's (et al.) technique for calculation of (nominally) stabilizing PI and PID controllers or robustly stabilizing PI controllers by means of plotting the stability boundary locus in either P-I plane or P-I-D space. Refinement of the existing method by consideration of 16 segment plants instead of 16 Kharitonov plants provides an elegant and efficient tool for finding all robustly stabilizing PID controllers for an interval system. The validity and relatively effortless application of presented theoretical concepts are demonstrated through a computation and simulation example in which the uncertain mathematical model of an experimental oblique wing aircraft is robustly stabilized.

  11. Global robust exponential stability analysis for interval recurrent neural networks

    International Nuclear Information System (INIS)

    Xu Shengyuan; Lam, James; Ho, Daniel W.C.; Zou Yun

    2004-01-01

    This Letter investigates the problem of robust global exponential stability analysis for interval recurrent neural networks (RNNs) via the linear matrix inequality (LMI) approach. The values of the time-invariant uncertain parameters are assumed to be bounded within given compact sets. An improved condition for the existence of a unique equilibrium point and its global exponential stability of RNNs with known parameters is proposed. Based on this, a sufficient condition for the global robust exponential stability for interval RNNs is obtained. Both of the conditions are expressed in terms of LMIs, which can be checked easily by various recently developed convex optimization algorithms. Examples are provided to demonstrate the reduced conservatism of the proposed exponential stability condition

  12. Single interval Rényi entropy at low temperature

    Science.gov (United States)

    Chen, Bin; Wu, Jie-qiang

    2014-08-01

    In this paper, we calculate the Rényi entropy of one single interval on a circle at finite temperature in 2D CFT. In the low temperature limit, we expand the thermal density matrix level by level in the vacuum Verma module, and calculate the first few leading terms in e -π/ T L explicitly. On the other hand, we compute the same Rényi entropy holographically. After considering the dependence of the Rényi entropy on the temperature, we manage to fix the interval-independent constant terms in the classical part of holographic Rényi entropy. We furthermore extend the analysis in [9] to higher orders and find exact agreement between the results from field theory and bulk computations in the large central charge limit. Our work provides another piece of evidence to support holographic computation of Rényi entropy in AdS3/CFT2 correspondence, even with thermal effect.

  13. Lithography cycle time improvements using short-interval scheduling

    Science.gov (United States)

    Norman, David; Watson, Scott; Anderson, Michael; Marteney, Steve; Mehr, Ben

    2010-04-01

    Partially and fully automated semiconductor manufacturing facilities around the world have employed automated real-time dispatchers (RTD) as a critical element of their factory management solutions. The success of RTD is attributable to a detailed and extremely accurate data base that reflects the current state of the factory, consistently applied dispatching policies and continuous improvement of these dispatching policies. However, many manufactures are now reaching the benefit limits of pure dispatching-based or other "heuristic-only" solutions. A new solution is needed that combines locally optimized short-interval schedules with RTD policies to target further reductions in product cycle time. This paper describes an integrated solution that employs four key components: 1. real-time data generation, 2. simulation-based prediction, 3. locally optimized short-interval scheduling, and 4. schedule-aware real-time dispatching. The authors describe how this solution was deployed in lithography and wet / diffusion areas, and report the resulting improvements measured.

  14. Research on Driver Behavior in Yellow Interval at Signalized Intersections

    Directory of Open Access Journals (Sweden)

    Zhaosheng Yang

    2014-01-01

    Full Text Available Vehicles are often caught in dilemma zone when they approach signalized intersections in yellow interval. The existence of dilemma zone which is significantly influenced by driver behavior seriously affects the efficiency and safety of intersections. This paper proposes the driver behavior models in yellow interval by logistic regression and fuzzy decision tree modeling, respectively, based on camera image data. Vehicle’s speed and distance to stop line are considered in logistic regression model, which also brings in a dummy variable to describe installation of countdown timer display. Fuzzy decision tree model is generated by FID3 algorithm whose heuristic information is fuzzy information entropy based on membership functions. This paper concludes that fuzzy decision tree is more accurate to describe driver behavior at signalized intersection than logistic regression model.

  15. Process control and optimization with simple interval calculation method

    DEFF Research Database (Denmark)

    Pomerantsev, A.; Rodionova, O.; Høskuldsson, Agnar

    2006-01-01

    Methods of process control and optimization are presented and illustrated with a real world example. The optimization methods are based on the PLS block modeling as well as on the simple interval calculation methods of interval prediction and object status classification. It is proposed to employ...... the series of expanding PLS/SIC models in order to support the on-line process improvements. This method helps to predict the effect of planned actions on the product quality and thus enables passive quality control. We have also considered an optimization approach that proposes the correcting actions...... for the quality improvement in the course of production. The latter is an active quality optimization, which takes into account the actual history of the process. The advocate approach is allied to the conventional method of multivariate statistical process control (MSPC) as it also employs the historical process...

  16. Interval Predictor Models for Data with Measurement Uncertainty

    Science.gov (United States)

    Lacerda, Marcio J.; Crespo, Luis G.

    2017-01-01

    An interval predictor model (IPM) is a computational model that predicts the range of an output variable given input-output data. This paper proposes strategies for constructing IPMs based on semidefinite programming and sum of squares (SOS). The models are optimal in the sense that they yield an interval valued function of minimal spread containing all the observations. Two different scenarios are considered. The first one is applicable to situations where the data is measured precisely whereas the second one is applicable to data subject to known biases and measurement error. In the latter case, the IPMs are designed to fully contain regions in the input-output space where the data is expected to fall. Moreover, we propose a strategy for reducing the computational cost associated with generating IPMs as well as means to simulate them. Numerical examples illustrate the usage and performance of the proposed formulations.

  17. Recommended Changes to Interval Management to Achieve Operational Implementation

    Science.gov (United States)

    Baxley, Brian; Swieringa, Kurt; Roper, Roy; Hubbs, Clay; Goess, Paul; Shay, Richard

    2017-01-01

    A 19-day flight test of an Interval Management (IM) avionics prototype was conducted in Washington State using three aircraft to precisely achieve and maintain a spacing interval behind the preceding aircraft. NASA contracted with Boeing, Honeywell, and United Airlines to build this prototype, and then worked closely with them, the FAA, and other industry partners to test this prototype in flight. Four different IM operation types were investigated during this test in the en route, arrival, and final approach phases of flight. Many of the IM operations met or exceeded the design goals established prior to the test. However, there were issues discovered throughout the flight test, including the rate and magnitude of IM commanded speed changes and the difference between expected and actual aircraft deceleration rates.

  18. Optimization of testing and maintenance intervals of standby units

    International Nuclear Information System (INIS)

    Vaurio, J.

    1996-01-01

    The time-dependent unavailability of periodically tested aging components is studied under various maintenance policies in which component renewal may or may not take place in tests or repairs. Analytical and numerical results are developed especially for the case that neither tests nor repairs nenew a component. The role of periodic preventive maintenance is analyzed in details, developing criteria and equations for economic optimization of periodic testing and maintenance intervals. The costs of these actions as well as the costs of repairs and accidents that may occur due to failures are taken into account. The roles of different cost and aging parameters are clearly visible in the results. Explicit optimum intervals are obtained in case of a generalized Weibull hazard rate. (orig.) (22 refs.)

  19. Comparison of Bootstrap Confidence Intervals Using Monte Carlo Simulations

    Directory of Open Access Journals (Sweden)

    Roberto S. Flowers-Cano

    2018-02-01

    Full Text Available Design of hydraulic works requires the estimation of design hydrological events by statistical inference from a probability distribution. Using Monte Carlo simulations, we compared coverage of confidence intervals constructed with four bootstrap techniques: percentile bootstrap (BP, bias-corrected bootstrap (BC, accelerated bias-corrected bootstrap (BCA and a modified version of the standard bootstrap (MSB. Different simulation scenarios were analyzed. In some cases, the mother distribution function was fit to the random samples that were generated. In other cases, a distribution function different to the mother distribution was fit to the samples. When the fitted distribution had three parameters, and was the same as the mother distribution, the intervals constructed with the four techniques had acceptable coverage. However, the bootstrap techniques failed in several of the cases in which the fitted distribution had two parameters.

  20. A general method for enclosing solutions of interval linear equations

    Czech Academy of Sciences Publication Activity Database

    Rohn, Jiří

    2012-01-01

    Roč. 6, č. 4 (2012), s. 709-717 ISSN 1862-4472 R&D Projects: GA ČR GA201/09/1957; GA ČR GC201/08/J020 Institutional research plan: CEZ:AV0Z10300504 Keywords : interval linear equations * solution set * enclosure * absolute value inequality Subject RIV: BA - General Mathematics Impact factor: 1.654, year: 2012

  1. Integers without large prime factors in short intervals: Conditional ...

    Indian Academy of Sciences (India)

    α > 0 the interval (X, X +. √. X(log X)1/2+o(1)] contains an integer having no prime factor exceeding Xα for all X sufficiently large. Keywords. Smooth numbers; Riemann zeta function. 1. Introduction. Suppose P (n) denotes the largest prime factor of an integer n > 1 and let us declare. P(1) = 1. Given a positive real number y, ...

  2. Better Confidence Intervals: The Double Bootstrap with No Pivot

    OpenAIRE

    David Letson; B.D. McCullough

    1998-01-01

    The double bootstrap is an important advance in confidence interval generation because it converges faster than the already popular single bootstrap. Yet the usual double bootstrap requires a stable pivot that is not always available, e.g., when estimating flexibilities or substitution elasticities. A recently developed double bootstrap does not require a pivot. A Monte Carlo analysis with the Waugh data finds the double bootstrap achieves nominal coverage whereas the single bootstrap does no...

  3. PR Interval Prolongation and Cryptogenic Stroke: A Multicenter Retrospective Study.

    Science.gov (United States)

    Montalvo, Mayra; Tadi, Prasanna; Merkler, Alexander; Gialdini, Gino; Martin-Schild, Sheryl; Navalkele, Digvijaya; Samai, Alyana; Nouh, Amre; Hussain, Mohammad; Goldblatt, Steven; Hemendinger, Morgan; Chu, Antony; Song, Christopher; Kamel, Hooman; Furie, Karen L; Yaghi, Shadi

    2017-10-01

    Atrial dysfunction or "cardiopathy" has been recently proposed as a mechanism in cryptogenic stroke. A prolonged PR interval may reflect impaired atrial conduction and thus may be a biomarker of atrial cardiopathy. We aim to compare the prevalence of PR interval prolongation in patients with cryptogenic stroke (CS) when compared with known non-cryptogenic non-cardioembolic stroke (NCNCS) subtypes. We used prospective ischemic stroke databases of 3 comprehensive stroke centers to identify patients 18 years or older with a discharge diagnosis of ischemic non-cardioembolic stroke between December 1, 2013 and August 31, 2015. The main outcome was ischemic stroke subtype (CS versus NCNCS). We compared PR intervals as a continuous and categorical variable (PR interval prolongation and CS. We identified 644 patients with ischemic non-cardioembolic stroke (224 CS and 420 NCNCS). Patients with CS were more likely to have a PR of 200 milliseconds or greater when compared with those with NCNCS (23.2% versus 13.8%, P = .009). After adjusting for factors that were significant in univariate analyses, a PR of 200 milliseconds or greater was independently associated with CS (odds ratio [OR] 1.70, 95% CI 1.08-2.70). The association was more pronounced when excluding patients on atrioventricular nodal blocking agents (OR 2.64, 95% CI 1.44-4.83). A PR of 200 milliseconds or greater is associated with CS and may be a biomarker of atrial cardiopathy in the absence of atrial fibrillation. Prospective studies are needed to confirm this association. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  4. Crossed interval groups and operations on the Hochschild cohomology

    Czech Academy of Sciences Publication Activity Database

    Batanin, M.; Markl, Martin

    2014-01-01

    Roč. 8, č. 3 (2014), s. 655-693 ISSN 1661-6952 R&D Projects: GA ČR GA201/08/0397 Institutional support: RVO:67985840 Keywords : crossed interval group * Hochschild cohomology * natural operation Subject RIV: BA - General Mathematics Impact factor: 0.947, year: 2014 http://www.ems-ph.org/journals/show_abstract.php?issn=1661-6952&vol=8&iss=3&rank=2

  5. The effect of different rest intervals between multiple bench press ...

    African Journals Online (AJOL)

    In order to examine the effects of different rest intervals between sets on the training volume completed during a workout, 15 male bodybuilders served as subjects (Mean SD, age=25.28±2.01; mass=73.06±8.33 kg; height=176.33±6.30 cm). All the subjects performed a minimum of three strength workouts per week for a ...

  6. Audiovisual Interval Size Estimation Is Associated with Early Musical Training.

    Science.gov (United States)

    Abel, Mary Kathryn; Li, H Charles; Russo, Frank A; Schlaug, Gottfried; Loui, Psyche

    2016-01-01

    Although pitch is a fundamental attribute of auditory perception, substantial individual differences exist in our ability to perceive differences in pitch. Little is known about how these individual differences in the auditory modality might affect crossmodal processes such as audiovisual perception. In this study, we asked whether individual differences in pitch perception might affect audiovisual perception, as it relates to age of onset and number of years of musical training. Fifty-seven subjects made subjective ratings of interval size when given point-light displays of audio, visual, and audiovisual stimuli of sung intervals. Audiovisual stimuli were divided into congruent and incongruent (audiovisual-mismatched) stimuli. Participants' ratings correlated strongly with interval size in audio-only, visual-only, and audiovisual-congruent conditions. In the audiovisual-incongruent condition, ratings correlated more with audio than with visual stimuli, particularly for subjects who had better pitch perception abilities and higher nonverbal IQ scores. To further investigate the effects of age of onset and length of musical training, subjects were divided into musically trained and untrained groups. Results showed that among subjects with musical training, the degree to which participants' ratings correlated with auditory interval size during incongruent audiovisual perception was correlated with both nonverbal IQ and age of onset of musical training. After partialing out nonverbal IQ, pitch discrimination thresholds were no longer associated with incongruent audio scores, whereas age of onset of musical training remained associated with incongruent audio scores. These findings invite future research on the developmental effects of musical training, particularly those relating to the process of audiovisual perception.

  7. Opinion Paper: Deriving Harmonised Reference Intervals – Global Activities

    Science.gov (United States)

    Koerbin, Gus; Adeli, Khosrow

    2016-01-01

    Harmonisation of reference intervals (RIs) refers to use of the same or common RI across different platforms and /or assays for a specified analyte. It occurs optimally for those analytes where there is sound calibration and traceability in place and evidence from a between-method comparison shows that bias would not prevent the use of a common RI. The selection of the RI will depend on various sources of information including local formal RI studies, published studies from the literature, laboratory surveys, manufacturer’s product information, relevant guidelines, and mining of databases. Pre-analytical and partitioning issues, significant figures and flagging rates, are assessed for each analyte. Several countries and regions including the Nordic countries, United Kingdom, Japan, Turkey, and Australasia are using common RIs that have been determined either by direct studies or by a consensus process. In Canada, the Canadian Society of Clinical Chemists Taskforce is assessing the feasibility of establishing common reference values using the CALIPER (Canadian Laboratory Initiative on Pediatric Reference Intervals) and CHMS (The Canadian Health Measures Survey) databases as the basis. Development of platform-specific common reference values for each of the major analytical systems may be a more practical approach especially for the majority of analytes that are not standardised against a primary reference method and are not traceable to a primary or secondary reference material. We encourage laboratories to consider adopting reference intervals consistent with those used by other laboratories in your region where it is possible and appropriate for your local population. Local validation of the adopted reference interval is also recommended as per CLSI guidelines. PMID:27683506

  8. Opinion Paper: Deriving Harmonised Reference Intervals - Global Activities.

    Science.gov (United States)

    Tate, Jillian R; Koerbin, Gus; Adeli, Khosrow

    2016-02-01

    Harmonisation of reference intervals (RIs) refers to use of the same or common RI across different platforms and /or assays for a specified analyte. It occurs optimally for those analytes where there is sound calibration and traceability in place and evidence from a between-method comparison shows that bias would not prevent the use of a common RI. The selection of the RI will depend on various sources of information including local formal RI studies, published studies from the literature, laboratory surveys, manufacturer's product information, relevant guidelines, and mining of databases. Pre-analytical and partitioning issues, significant figures and flagging rates, are assessed for each analyte. Several countries and regions including the Nordic countries, United Kingdom, Japan, Turkey, and Australasia are using common RIs that have been determined either by direct studies or by a consensus process. In Canada, the Canadian Society of Clinical Chemists Taskforce is assessing the feasibility of establishing common reference values using the CALIPER (Canadian Laboratory Initiative on Pediatric Reference Intervals) and CHMS (The Canadian Health Measures Survey) databases as the basis. Development of platform-specific common reference values for each of the major analytical systems may be a more practical approach especially for the majority of analytes that are not standardised against a primary reference method and are not traceable to a primary or secondary reference material. We encourage laboratories to consider adopting reference intervals consistent with those used by other laboratories in your region where it is possible and appropriate for your local population. Local validation of the adopted reference interval is also recommended as per CLSI guidelines.

  9. [Assesment of Parameters of QT Interval in Children and Adolescents.].

    Science.gov (United States)

    Makarov, L M; Kisileva, I I; Dolgikh, V V; Bimbaev, A B-Zh; Bairova, T A; Drozdova, A I

    2006-01-01

    Aim. To determine limits of interval QT in children and adolescents aged 0-17 years and to detect possible ethnic differences of its changes. Material and Method. Twelve lead ECGs were recorded in 1531 subjects without overt cardiovascular pathology (47.2% females, 52.8 males, 57.3% of Slavic and 42.7% of Buryat i.e. mongoloid ethnicity). Results. Corrected QT interval (QTc) exceeded 440, 460 and 480 ms in 2.3, 1.05, and 0.26% of children. Prolongation of QTc was found in 0.46% and 0.11% of Slavic and Buryat children, respectively (p=ns). Starting from the age of 8 years girls had longer QTc than boys (454.1+/-15.2 and 438.3+/-8.4 ms, respectively, pchildren (0.78%). Eight of these children with mean QTc 329.1+/-32.3 ms had family history of syncope or sudden death. Variability of absolute QT values was 8+/-14.3 ms (maximally up to 40 ms). Conclusions. QT interval is prolonged when QTc duration exceeds 440 ms in children younger than 8 years and in male adolescents or 460 ms in girls aged 8 years or older and in children during first year of life. QT interval is shortened when QTc is less than 350 ms (1st degree of shortening). In children with QTc below 330 ms (2nd degree of shortening) short QT syndrome should be excluded. Normal variability of absolute QT value during sinus arrhythm on ECG at rest does not exceed 40 ms.

  10. Encoding of temporal intervals in the rat hindlimb sensorimotor cortex

    Directory of Open Access Journals (Sweden)

    Eric Bean Knudsen

    2012-09-01

    Full Text Available The gradual buildup of neural activity over experimentally imposed delay periods, termed climbing activity, is well documented and is a potential mechanism by which interval time is encoded by distributed cortico-thalamico-striatal networks in the brain. Additionally, when multiple delay periods are incorporated, this activity has been shown to scale its rate of climbing proportional to the delay period. However, it remains unclear whether these patterns of activity occur within areas of motor cortex dedicated to hindlimb movement. Moreover, the effects of behavioral training (e.g. motor tasks under different reward conditions but with similar behavioral output are not well addressed. To address this, we recorded activity from the hindlimb sensorimotor cortex (HLSMC of two groups of rats performing a skilled hindlimb press task. In one group, rats were trained only to a make a valid press within a finite window after cue presentation for reward (non-interval trained, nIT; n=5, while rats in the second group were given duration-specific cues in which they had to make presses of either short or long duration to receive reward (interval trained, IT; n=6. Using PETH analyses, we show that cells recorded from both groups showed climbing activity during the task in similar proportions (35% IT and 47% nIT, however only climbing activity from IT rats was temporally scaled to press duration. Furthermore, using single trial decoding techniques (Wiener filter, we show that press duration can be inferred using climbing activity from IT animals (R=0.61 significantly better than nIT animals (R=0.507, p<0.01, suggesting IT animals encode press duration through temporally scaled climbing activity. Thus, if temporal intervals are behaviorally relevant then the activity of climbing neurons is temporally scaled to encode the passage of time.

  11. Effective Topological Degree Computation Based on Interval Arithmetic

    Czech Academy of Sciences Publication Activity Database

    Franek, Peter; Ratschan, Stefan

    2015-01-01

    Roč. 84, č. 293 (2015), s. 1265-1290 ISSN 0025-5718 R&D Projects: GA ČR GCP202/12/J060 Institutional support: RVO:67985807 Keywords : computational topology * interval computation Subject RIV: BA - General Mathematics Impact factor: 1.464, year: 2015 http://www.ams.org/journals/mcom/0000-000-00/S0025-5718-2014-02877-9/

  12. Translating QT interval prolongation from conscious dogs to humans.

    Science.gov (United States)

    Dubois, Vincent F S; Smania, Giovanni; Yu, Huixin; Graf, Ramona; Chain, Anne S Y; Danhof, Meindert; Della Pasqua, Oscar

    2017-02-01

    In spite of screening procedures in early drug development, uncertainty remains about the propensity of new chemical entities (NCEs) to prolong the QT/QTc interval. The evaluation of proarrhythmic activity using a comprehensive in vitro proarrhythmia assay does not fully account for pharmacokinetic-pharmacodynamic (PKPD) differences in vivo. In the present study, we evaluated the correlation between drug-specific parameters describing QT interval prolongation in dogs and in humans. Using estimates of the drug-specific parameter, data on the slopes of the PKPD relationships of nine compounds with varying QT-prolonging effects (cisapride, sotalol, moxifloxacin, carabersat, GSK945237, SB237376 and GSK618334, and two anonymized NCEs) were analysed. Mean slope estimates varied between -0.98 ms μM -1 and 6.1 ms μM -1 in dogs and -10 ms μM -1 and 90 ms μM -1 in humans, indicating a wide range of effects on the QT interval. Linear regression techniques were then applied to characterize the correlation between the parameter estimates across species. For compounds without a mixed ion channel block, a correlation was observed between the drug-specific parameter in dogs and humans (y = -1.709 + 11.6x; R 2  = 0.989). These results show that per unit concentration, the drug effect on the QT interval in humans is 11.6-fold larger than in dogs. Together with information about the expected therapeutic exposure, the evidence of a correlation between the compound-specific parameter in dogs and in humans represents an opportunity for translating preclinical safety data before progression into the clinic. Whereas further investigation is required to establish the generalizability of our findings, this approach can be used with clinical trial simulations to predict the probability of QT prolongation in humans. © 2016 The British Pharmacological Society.

  13. Comparison of Bootstrap Confidence Intervals Using Monte Carlo Simulations

    OpenAIRE

    Roberto S. Flowers-Cano; Ruperto Ortiz-Gómez; Jesús Enrique León-Jiménez; Raúl López Rivera; Luis A. Perera Cruz

    2018-01-01

    Design of hydraulic works requires the estimation of design hydrological events by statistical inference from a probability distribution. Using Monte Carlo simulations, we compared coverage of confidence intervals constructed with four bootstrap techniques: percentile bootstrap (BP), bias-corrected bootstrap (BC), accelerated bias-corrected bootstrap (BCA) and a modified version of the standard bootstrap (MSB). Different simulation scenarios were analyzed. In some cases, the mother distributi...

  14. Theophylline product and dosing interval selection for chronic asthma.

    Science.gov (United States)

    Hendeles, L; Weinberger, M

    1985-08-01

    Unless they are taken at unacceptably frequent intervals, conventional rapid-release theophylline tablets and liquids produce excessive serum concentration fluctuations, particularly in patients with rapid elimination. Slow-release formulations provide more stable serum concentrations with longer dosing intervals if absorbed completely, consistently, and at a sufficiently slow rate and thus have the potential to improve efficacy and compliance. However, there are clinically important differences in the extent and rate of absorption among the 15 slow-release formulations available under 29 brand names in the United States. Fluctuations in steady-state serum concentrations are a function of the absorption rate of the product, the elimination rate of the patient, and the dosing interval. In patients with slow elimination, clinically relevant differences among formulations are not apparent with twice-daily dosing. Among patients with more rapid elimination, however, available data for only two products demonstrate sufficiently slow absorption to justify routine twice-daily use without excessive fluctuations. More rapidly absorbed formulations must be administered at 8-hour intervals in such patients to prevent breakthrough in asthmatic symptoms before the next dose, despite promotional claims to the contrary. Current products approved for "once-a-day" dosing are clinically inadequate because of incomplete or erratic absorption or excessive serum concentration fluctuations. Lastly, food intake induces dose dumping of potentially toxic amounts of theophylline from Theo-24 and greatly impairs absorption from Theo-Dur Sprinkle capsules but has no important effect on Theo-Dur tablets. The effects of food on most other theophylline products are not known.

  15. Audiovisual Interval Size Estimation Is Associated with Early Musical Training.

    Directory of Open Access Journals (Sweden)

    Mary Kathryn Abel

    Full Text Available Although pitch is a fundamental attribute of auditory perception, substantial individual differences exist in our ability to perceive differences in pitch. Little is known about how these individual differences in the auditory modality might affect crossmodal processes such as audiovisual perception. In this study, we asked whether individual differences in pitch perception might affect audiovisual perception, as it relates to age of onset and number of years of musical training. Fifty-seven subjects made subjective ratings of interval size when given point-light displays of audio, visual, and audiovisual stimuli of sung intervals. Audiovisual stimuli were divided into congruent and incongruent (audiovisual-mismatched stimuli. Participants' ratings correlated strongly with interval size in audio-only, visual-only, and audiovisual-congruent conditions. In the audiovisual-incongruent condition, ratings correlated more with audio than with visual stimuli, particularly for subjects who had better pitch perception abilities and higher nonverbal IQ scores. To further investigate the effects of age of onset and length of musical training, subjects were divided into musically trained and untrained groups. Results showed that among subjects with musical training, the degree to which participants' ratings correlated with auditory interval size during incongruent audiovisual perception was correlated with both nonverbal IQ and age of onset of musical training. After partialing out nonverbal IQ, pitch discrimination thresholds were no longer associated with incongruent audio scores, whereas age of onset of musical training remained associated with incongruent audio scores. These findings invite future research on the developmental effects of musical training, particularly those relating to the process of audiovisual perception.

  16. Stability Problem of Canard-Cycles on a Finite Interval

    Science.gov (United States)

    Chumakov, Gennadii A.; Chumakova, Nataliya A.; Lashina, Elena A.

    2010-09-01

    A detailed study of two-variable mathematical model of a heterogeneous catalytic reaction is presented with special attention to the stability problem of canard-cycles on a finite interval. Our analysis of the global error behavior in a long-time numerical integration shows that a high sensitive dependence on the initial conditions appears due to the existence of a shower-type bundle of trajectories which is formed by stable and unstable canard solutions.

  17. Nosewitness Identification: Effects of Lineup Size and Retention Interval.

    Science.gov (United States)

    Alho, Laura; Soares, Sandra C; Costa, Liliana P; Pinto, Elisa; Ferreira, Jacqueline H T; Sorjonen, Kimmo; Silva, Carlos F; Olsson, Mats J

    2016-01-01

    Although canine identification of body odor (BO) has been widely used as forensic evidence, the concept of nosewitness identification by human observers was only recently put to the test. The results indicated that BOs associated with male characters in authentic crime videos could later be identified in BO lineup tests well above chance. To further evaluate nosewitness memory, we assessed the effects of lineup size (Experiment 1) and retention interval (Experiment 2), using a forced-choice memory test. The results showed that nosewitness identification works for all lineup sizes (3, 5, and 8 BOs), but that larger lineups compromise identification performance in similarity to observations from eye- and earwitness studies. Also in line with previous eye- and earwitness studies, but in disagreement with some studies on odor memory, Experiment 2 showed significant forgetting between shorter retention intervals (15 min) and longer retention intervals (1-week) using lineups of five BOs. Altogether this study shows that identification of BO in a forensic setting is possible and has limits and characteristics in line with witness identification through other sensory modalities.

  18. Perception of acoustically presented time series with varied intervals.

    Science.gov (United States)

    Wackermann, Jiří; Pacer, Jakob; Wittmann, Marc

    2014-03-01

    Data from three experiments on serial perception of temporal intervals in the supra-second domain are reported. Sequences of short acoustic signals ("pips") separated by periods of silence were presented to the observers. Two types of time series, geometric or alternating, were used, where the modulus 1+δ of the inter-pip series and the base duration Tb (range from 1.1 to 6s) were varied as independent parameters. The observers had to judge whether the series were accelerating, decelerating, or uniform (3 paradigm), or to distinguish regular from irregular sequences (2 paradigm). "Intervals of subjective uniformity" (isus) were obtained by fitting Gaussian psychometric functions to individual subjects' responses. Progression towards longer base durations (Tb=4.4 or 6s) shifts the isus towards negative δs, i.e., accelerating series. This finding is compatible with the phenomenon of "subjective shortening" of past temporal intervals, which is naturally accounted for by the lossy integration model of internal time representation. The opposite effect observed for short durations (Tb=1.1 or 1.5s) remains unexplained by the lossy integration model, and presents a challenge for further research. © 2013 Elsevier B.V. All rights reserved.

  19. Security Enhancement of Wireless Sensor Networks Using Signal Intervals.

    Science.gov (United States)

    Moon, Jaegeun; Jung, Im Y; Yoo, Jaesoo

    2017-04-02

    Various wireless technologies, such as RF, Bluetooth, and Zigbee, have been applied to sensor communications. However, the applications of Bluetooth-based wireless sensor networks (WSN) have a security issue. In one pairing process during Bluetooth communication, which is known as simple secure pairing (SSP), the devices are required to specify I/O capability or user interference to prevent man-in-the-middle (MITM) attacks. This study proposes an enhanced SSP in which a nonce to be transferred is converted to a corresponding signal interval. The quantization level, which is used to interpret physical signal intervals, is renewed at every connection by the transferred nonce and applied to the next nonce exchange so that the same signal intervals can represent different numbers. Even if attackers eavesdrop on the signals, they cannot understand what is being transferred because they cannot determine the quantization level. Furthermore, the proposed model does not require exchanging passkeys as data, and the devices are secure in the case of using a fixed PIN. Subsequently, the new quantization level is calculated automatically whenever the same devices attempt to connect with each other. Therefore, the pairing process can be protected from MITM attacks and be convenient for users.

  20. Security Enhancement of Wireless Sensor Networks Using Signal Intervals

    Directory of Open Access Journals (Sweden)

    Jaegeun Moon

    2017-04-01

    Full Text Available Various wireless technologies, such as RF, Bluetooth, and Zigbee, have been applied to sensor communications. However, the applications of Bluetooth-based wireless sensor networks (WSN have a security issue. In one pairing process during Bluetooth communication, which is known as simple secure pairing (SSP, the devices are required to specify I/O capability or user interference to prevent man-in-the-middle (MITM attacks. This study proposes an enhanced SSP in which a nonce to be transferred is converted to a corresponding signal interval. The quantization level, which is used to interpret physical signal intervals, is renewed at every connection by the transferred nonce and applied to the next nonce exchange so that the same signal intervals can represent different numbers. Even if attackers eavesdrop on the signals, they cannot understand what is being transferred because they cannot determine the quantization level. Furthermore, the proposed model does not require exchanging passkeys as data, and the devices are secure in the case of using a fixed PIN. Subsequently, the new quantization level is calculated automatically whenever the same devices attempt to connect with each other. Therefore, the pairing process can be protected from MITM attacks and be convenient for users.

  1. Establishment of complete blood count reference intervals for Chinese preschoolers.

    Science.gov (United States)

    Wang, Guo-Cheng; Li, Na; Niu, Cui; Ma, Wei-Bo; Wang, Zhu-Liang; Guo, Hao; Han, Li-Hong

    2017-09-01

    Reference intervals are critical for interpreting test results of a clinical laboratory. The aim of this study was to establish local reference intervals of complete blood count for healthy preschoolers in China. Three thousand eight hundred and twenty-one blood specimens from children aged 4 months to 6 years were collected and analyzed. Complete blood counts were determined by Sysmex XT-4000i Automated Hematology Analyzer. The nonparametric 2.5th to 97.5th percentile reference ranges were calculated according to CLSI EP28-A3c guideline. Reference intervals for each blood cell parameter are determinded as follows: total WBC 4.86-12.1×10 9 /L for males and 4.73-12.3×10 9 /L for females; RBC 4.13-5.32×10 12 /L for males and 4.08-5.24×10 12 /L for females; HGB 109-145 g/L for males and 111-143 g/L for females; HCT 33.1-41.2% for males and 33.3-41.1% for females; MCH 23.5-29.7 pg for males and 24.6-30.0 pg for females; MCHC 320-365 g/L for males and 321-362 g/L for females; MCV 71.4-85.1 fL for males and 73.8-86.9 fL for females; RDW-SD 33.5-41.9 fL for males and 33.5-41.0 fL for females; RDW-CV 12.0-15.2% for males and 11.8-14.5% for females; PLT 181-475×10 9 /L for males and 179-456×10 9 /L for females; PCT 0.18-0.44% for males and 0.18-0.43% for females; MPV 8.20-11.6 fL for males and 8.20-11.5 fL for females; PDW 8.40-14.4 fL for males and 8.40-14.0 fL for females; P-LCR 12.0-36.6% for males and 11.8-35.6% for females. We established local complete blood count reference intervals for apparent healthy preschoolers in China. It is necessary to establishing region-specific reference intervals of complete blood count for preschoolers. © 2016 Wiley Periodicals, Inc.

  2. Right Propositional Neighborhood Logic over Natural Numbers with Integer Constraints for Interval Lengths

    DEFF Research Database (Denmark)

    Bresolin, Davide; Goranko, Valentin; Montanari, Angelo

    2009-01-01

    Interval temporal logics are based on interval structures over linearly (or partially) ordered domains, where time intervals, rather than time instants, are the primitive ontological entities. In this paper we introduce and study Right Propositional Neighborhood Logic over natural numbers...

  3. Small Sample Confidence Intervals in Log Space Back-Transformed from Normal Space

    National Research Council Canada - National Science Library

    Tisdel, Jason E

    2006-01-01

    .... Analysis in the normal space provides point estimates and confidence intervals, but transformation back to the original space using the naive approach yields confidence intervals of impractical width...

  4. Designing Yellow Intervals for Rainy and Wet Roadway Conditions

    Directory of Open Access Journals (Sweden)

    Huan Li

    2012-06-01

    Full Text Available The research presented in this paper quantifies and models the impact of wet pavement surface and rainy weather conditions on driver perception-reaction times (PRTs, deceleration levels, and traffic signal change interval durations. A total of 648 stop-run records were collected as part of the research effort for a 72 km/h (45 mi/h approach speed where participant drivers encountered a yellow indication initiation at different distances from the intersection. The participant drivers were randomly selected in different age groups (under 40 years old, 40 to 59 years old, and 60 years of age or older and genders (female and male. Using the gathered data, statistical models for driver PRT and deceleration levels were developed, considering roadway surface and environmental parameters, driver attributes (age and gender, roadway grade, approaching speed, and time and distance to the intersection at the onset of yellow. Inclement weather yellow timings were then developed and summarized in lookup tables as a function of different factors (driver age/gender, roadway grade, speed limit, precipitation level, and roadway surface condition to provide practical guidelines for the design of yellow signal timings in wet and rainy weather conditions. The results indicate that wet roadway surface conditions require a 5 percent increase in the change interval and that rainy conditions require a 10 percent or more increase in the duration of the change interval. These recommended change durations can also be integrated within the Vehicle Infrastructure Integration (VII initiative to provide customizable driver warnings prior to a transition to a red indication.

  5. Interepisode Sleep Bruxism Intervals and Myofascial Face Pain.

    Science.gov (United States)

    Muzalev, Konstantin; Lobbezoo, Frank; Janal, Malvin N; Raphael, Karen G

    2017-08-01

    Sleep bruxism (SB) is considered as a possible etiological factor for temporomandibular disorder (TMD) pain. However, polysomnographic (PSG) studies, which are current "gold standard" diagnostic approach to SB, failed to prove an association between SB and TMD. A possible explanation could be that PSG studies have considered only limited characteristics of SB activity: the number of SB events per hour and, sometimes, the total duration of SB per night. According to the sports sciences literature, lack of adequate rest time between muscle activities leads to muscle overloading and pain. Therefore, the aim of this study was to determine whether the intervals between bruxism events differ between patients with and without TMD pain. Two groups of female volunteers were recruited: myofascial TMD pain group (n=124) and non-TMD control group (n=46). From these groups, we selected 86 (69%) case participants and 37 (80%) controls who had at least two SB episodes per night based on PSG recordings. A linear mixed model was used to compare case and control groups over the repeated observations of interepisode intervals. The duration of interepisode intervals was statistically similar in the case (mean [standard deviation {SD}] 1137.7 [1975.8] seconds)] and control (mean [SD] 1192.0 [1972.0] seconds) groups. There were also a similar number of SB episodes per hour and a total duration of SB episodes in both groups. The current data fail to support the idea that TMD pain can be explained by increasing number of SB episodes per hour of sleep or decreasing the time between SB events. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

  6. Reference intervals of echocardiographic measurements in healthy adult dairy goats.

    Science.gov (United States)

    Szaluś-Jordanow, Olga; Czopowicz, Michał; Witkowski, Lucjan; Mickiewicz, Marcin; Frymus, Tadeusz; Markowska-Daniel, Iwona; Bagnicka, Emilia; Kaba, Jarosław

    2017-01-01

    To determine references intervals for echocardiographic measurements in adult dairy goats. 125 clinically healthy, adult dairy goats aged 2-9 years, belonging to two breeds-Polish Fawn Improved (PFI, n = 64, weight range from 46 to 73, median of 58.5kg) and Polish White Improved (PWI, n = 61, weight range from 48 to 80 kg, median of 67.9kg), closely related to French Alpine and Saanen, respectively. Non-invasive transthoracic echocardiography examination was performed in unsedated goats in a standing position. Two-dimensional, M-mode and pulsed wave Doppler measurements were obtained. A non-parametric method was applied for determination of reference intervals. Measurements for the two breeds were compared using an analysis of covariance to control for their body weight. Repeatability was assessed using a between-day coefficient of variation and a coefficient of repeatability. Following reference intervals were determined: aortic diameter in diastole 2.2-3.3, left atrial diameter in systole 2.5-4.3cm cm, the ratio of the left atrial diameter to the aortic diameter 0.96-1.5, right ventricular internal diameter in diastole 0.4-1.7cm, left ventricular internal diameter in systole and diastole 1.8-3.2 and 3.2-5.6 cm, respectively, inter-ventricular septum thickness in systole and diastole 0.7-1.5 and 0.5-1.1cm, respectively, left ventricular posterior-wall in systole and diastole 0.8-1.6 and 0.5-1.2cm, respectively, E-point to septal separation 0.3-0.8cm, left ventricular fractional shortening 28-54%, left ventricular ejection fraction 55-86%, maximum Left and Right Ventricular Outflow Tract velocity 80-140 cm/s and 70-130 cm/s, respectively Left and Right Ventricular Outflow Tract pressure gradient 2.5-8.9mmHg and 1.9-6.5mmHg, respectively. Most of the differences between the two breeds could be attributed to different body weight. The study provides echocardiographic reference intervals determined on the highest sample of apparently healthy goats so far enrolled.

  7. GENERALIZED INVERSE INTERVAL METHOD OF GLOBAL CONSTRAINED OPTIMIZATION

    Directory of Open Access Journals (Sweden)

    A. V. Panteleyev

    2014-01-01

    Full Text Available The algorithmic and program software of inverse interval method for global constrained optimization are considered. The solution of model examples and the proof of the theorems of the algorithm’s convergence are presented. The generalized scheme of developed algorithms has been created. This scheme has two replaceable modules of compression and check. This module approach allows the users to implement their own versions of the algorithm without loss of the method convergence. This will help to tune the method according to the characteristics of the current problem.

  8. Stability of Rotation Pairs of Cycles for the Interval Maps

    Directory of Open Access Journals (Sweden)

    Taixiang Sun

    2011-01-01

    Full Text Available Let C0(I be the set of all continuous self-maps of the closed interval I, and P(u,v={f∈C0(I:f has a cycle with rotation pair (u,v} for any positive integer v>u. In this paper, we prove that if (2mns,2mnt⊣(γ,λ, then P(2mns,2mnt⊂  int  P(γ,λ, where m≥0 is integer, n≥1 odd, 1≤s

  9. Primary Surgery or Interval Debulking for Advanced Epithelial Ovarian Cancer

    DEFF Research Database (Denmark)

    Markauskas, Algirdas; Mogensen, Ole; dePont Christensen, René

    2014-01-01

    OBJECTIVE: The aim of the present study was to investigate the surgical complexity, the postoperative morbidity, and the survival of the women after primary debulking surgery (PDS) and neoadjuvant chemotherapy followed by interval debulking surgery (NACT-IDS) for advanced epithelial ovarian cancer....... MATERIALS AND METHODS: We consecutively included all patients who underwent debulking surgery at our institution between January 2007 and December 2012 for stages IIIc and IV of epithelial ovarian cancer. RESULTS: Of the 332 patients included, 165 (49.7%) underwent PDS, and 167 (50.3%) had NACT...

  10. Notas sobre la investigación-intervención

    OpenAIRE

    Pacheco, Gerardo

    1990-01-01

    Como parte del compromiso del ITESO de profundizar en su labor de investigación científica, así como de diseñar estrategias que permitan un cambio social, se explora la propuesta teórica del enfoque investigación-intervención en las ciencias sociales que, desde el punto de vista metodológico, establece la relación permanente entre el conocimiento y la acción. El conocimiento y la acción son vistos como son dos aspectos inseparables de la actividad humana; se relacionan dialécticamente, se con...

  11. Discriminator/time interval meter system evaluation report

    Energy Technology Data Exchange (ETDEWEB)

    Condreva, K. J.

    1976-04-12

    The purpose of this report is to discuss the evaluation of a modular prototype Discriminator/Time Interval Meter data acquisition unit as a useful tool in a digital diagnostics system. The characteristics, operation and calibration of each of the hardware components are discussed in some detail. A discussion of the system calibration, operation, and data ingestion and reduction is also given. System test results to date are given and discussed. Finally, recommendations and conclusions concerning the capabilities of the Discriminator/T.I.M. system based on test and calibration results to date are given.

  12. STUDY ON THE PARTICLE INJECTIONS DURING HILDCAA INTERVALS

    Directory of Open Access Journals (Sweden)

    Hee-Jeong Kim

    2007-06-01

    Full Text Available The relation between substorm occurrences and HILDCAA events has been an issue. We have studied the association of particle injections with substorm onsets during HILDCAA intervals for the first half of year 2003. The examination of aurora images observed by IMAGE spacecraft and electron flux data measured by LANL satellites exhibits a close association of repetitive particle injections with substorm activity. We also find that HILDCAA events can occur equally frequently during slow speed solar wind streams as long as the interplanetary magnetic field exhibits Alfvenic wave feature.

  13. The use of relative coupling intervals in horses during walk

    DEFF Research Database (Denmark)

    Olsen, Emil; Pfau, Thilo

    Walking speed varies between over-ground trials and a speed-independent gait-parameter does not exist for use in horses. We introduce relative (R) lateral (L) and diagonal (D) coupling intervals (CI) and hypothesize that both are independent of walking speed. Four horses were walked over 8 Kistler...... force plates surrounded by a 12-camera Qualisys infrared kinematic system. Kinetic and kinematic data were collected synchronously at a sample rate of 200 Hz. Hoof-on was detected from kinetic data with a threshold of 10N. LCI is defined as the time from front hoof-on to the ipsilateral hind hoof...

  14. Iterated maps on the interval as dynamical systems

    CERN Document Server

    Collet, Pierre

    2009-01-01

    Iterations of continuous maps of an interval to itself serve as the simplest examples of models for dynamical systems. These models present an interesting mathematical structure going far beyond the simple equilibrium solutions one might expect. If, in addition, the dynamical system depends on an experimentally controllable parameter, there is a corresponding mathematical structure revealing a great deal about interrelations between the behavior for different parameter values. This work explains some of the early results of this theory to mathematicians and theoretical physicists, with the add

  15. Dataset of manually measured QT intervals in the electrocardiogram

    Directory of Open Access Journals (Sweden)

    Prokopova Rada

    2006-05-01

    Full Text Available Abstract Background The QT interval and the QT dispersion are currently a subject of considerable interest. Cardiac repolarization delay is known to favor the development of arrhythmias. The QT dispersion, defined as the difference between the longest and the shortest QT intervals or as the standard deviation of the QT duration in the 12-lead ECG is assumed to be reliable predictor of cardiovascular mortality. The seventh annual PhysioNet/Computers in Cardiology Challenge, 2006 addresses a question of high clinical interest: Can the QT interval be measured by fully automated methods with accuracy acceptable for clinical evaluations? Method The PTB Diagnostic ECG Database was given to 4 cardiologists and 1 biomedical engineer for manual marking of QRS onsets and T-wave ends in 458 recordings. Each recording consisted of one selected beat in lead II, chosen visually to have minimum baseline shift, noise, and artifact. In cases where no T wave could be observed or its amplitude was very small, the referees were instructed to mark a 'group-T-wave end' taking into consideration leads with better manifested T wave. A modified Delphi approach was used, which included up to three rounds of measurements to obtain results closer to the median. Results A total amount of 2*5*548 Q-onsets and T-wave ends were manually marked during round 1. To obtain closer to the median results, 8.58 % of Q-onsets and 3.21 % of the T-wave ends had to be reviewed during round 2, and 1.50 % Q-onsets and 1.17 % T-wave ends in round 3. The mean and standard deviation of the differences between the values of the referees and the median after round 3 were 2.43 ± 0.96 ms for the Q-onset, and 7.43 ± 3.44 ms for the T-wave end. Conclusion A fully accessible, on the Internet, dataset of manually measured Q-onsets and T-wave ends was created and presented in additional file: 1 (Table 4 with this article. Thus, an available standard can be used for the development of automated

  16. Confidence Intervals from Realizations of Simulated Nuclear Data

    Energy Technology Data Exchange (ETDEWEB)

    Younes, W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ratkiewicz, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ressler, J. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-09-28

    Various statistical techniques are discussed that can be used to assign a level of confidence in the prediction of models that depend on input data with known uncertainties and correlations. The particular techniques reviewed in this paper are: 1) random realizations of the input data using Monte-Carlo methods, 2) the construction of confidence intervals to assess the reliability of model predictions, and 3) resampling techniques to impose statistical constraints on the input data based on additional information. These techniques are illustrated with a calculation of the keff value, based on the 235U(n, f) and 239Pu (n, f) cross sections.

  17. A Characterization of Strong Regularity of Interval Matrices

    Czech Academy of Sciences Publication Activity Database

    Rohn, Jiří

    2010-01-01

    Roč. 20, - (2010), s. 717-722 E-ISSN 1081-3810 R&D Projects: GA ČR GA201/09/1957; GA ČR GC201/08/J020 Institutional research plan: CEZ:AV0Z10300504 Keywords : interval matrix * strong regularity * spectral radius * matrix inequality * solvability Subject RIV: BA - General Mathematics Impact factor: 0.808, year: 2010 http://www.math.technion.ac.il/iic/ela/ela- articles / articles /vol20_pp717-722.pdf

  18. Selective inhibition of distracting input.

    Science.gov (United States)

    Noonan, MaryAnn P; Crittenden, Ben M; Jensen, Ole; Stokes, Mark G

    2017-10-16

    We review a series of studies exploring distractor suppression. It is often assumed that preparatory distractor suppression is controlled via top-down mechanisms of attention akin to those that prepare brain areas for target enhancement. Here, we consider two alternative mechanisms: secondary inhibition and expectation suppression within a predictive coding framework. We draw on behavioural studies, evidence from neuroimaging and some animal studies. We conclude that there is very limited evidence for selective top-down control of preparatory inhibition. By contrast, we argue that distractor suppression often relies secondary inhibition of non-target items (relatively non-selective inhibition) and on statistical regularities of the environment, learned through direct experience. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  19. The dynamic regulation of cortical excitability is altered in episodic ataxia type 2

    DEFF Research Database (Denmark)

    Helmich, Rick C; Siebner, Hartwig R; Giffin, Nicola

    2010-01-01

    Episodic ataxia type 2 and familial hemiplegic migraine are two rare hereditary disorders that are linked to dysfunctional ion channels and are characterized clinically by paroxysmal neurological symptoms. Impaired regulation of cerebral excitability is thought to play a role in the occurrence......-pulse transcranial magnetic stimulation at an interstimulus interval of 2 and 10 ms to assess intracortical inhibition and facilitation, respectively. The time course of burst-induced excitability changes differed between groups. Healthy controls showed a short-lived increase in excitability that was only present 50...... ms after the burst. In contrast, patients with episodic ataxia type 2 showed an abnormally prolonged increase in corticospinal excitability that was still present 250 ms after the transcranial magnetic stimulation burst. Furthermore, while controls showed a decrease in intracortical facilitation...

  20. The prognostic value of the QT interval and QT interval dispersion in all-cause and cardiac mortality and morbidity in a population of Danish citizens

    DEFF Research Database (Denmark)

    Elming, H; Holm, E; Jun, L

    1998-01-01

    AIMS: To evaluate the prognostic value of the QT interval and QT interval dispersion in total and in cardiovascular mortality, as well as in cardiac morbidity, in a general population. METHODS AND RESULTS: The QT interval was measured in all leads from a standard 12-lead ECG in a random sample of...

  1. Desarrollo cognitivo diferencial e intervención psicoeducativa

    Directory of Open Access Journals (Sweden)

    Sylvia Sastre i Riba

    2013-05-01

    Full Text Available En este artículo se revisa el concepto de desarrollo cognitivo desde una perspectiva neuroconstructivista actual y sus relaciones con la intervención psicoeduca-tiva. Desde esta perspectiva se postula que, para apresar el desarrollo en toda su ampli-tud multimodal, hay que atender al menos, a dos ejes: 1 el díferencial y, 2 la interacción (simétrica o asímétrica como fenómenos incidentes de forma específica en cada uno de los cursos de desarrollo alternativos que se contemplan: la deficiencia menta! (y dentro de ella el Síndrome de Down y las altas capacidades (y, dentro de ellas, la superdota-ción, postulando la necesidad de una intervención psicoeducativa ajustada a sus parti-cularidades, sin referencias anquilosantes provenientes de la perspectiva normativa = We propose a revision of the concept of cognitive development from a neuroconstructivist point of view and their relations with the psicoeducational practices. From this point of view, we postule that we must adopt two guide-lines in order to know as large as possible the concept of development: 1, the differential one, and, 2. interac-tion (symmetrical or asymmetrical as specific phenomenon in mental deficiency (con-cretely in Down's Syndrome ones and high intellectual abilities (concretely, giftedness. We postulate the necessity of a psicoeducational intervention adjusted to their capabili-ties and necessities without inmovilisms

  2. Interval prediction for graded multi-label classification

    CERN Document Server

    Lastra, Gerardo; Bahamonde, Antonio

    2014-01-01

    Multi-label was introduced as an extension of multi-class classification. The aim is to predict a set of classes (called labels in this context) instead of a single one, namely the set of relevant labels. If membership to the set of relevant labels is defined to a certain degree, the learning task is called graded multi-label classification. These learning tasks can be seen as a set of ordinal classifications. Hence, recommender systems can be considered as multi-label classification tasks. In this paper, we present a new type of nondeterministic learner that, for each instance, tries to predict at the same time the true grade for each label. When the classification is uncertain for a label, however, the hypotheses predict a set of consecutive grades, i.e., an interval. The goal is to keep the set of predicted grades as small as possible; while still containing the true grade. We shall see that these classifiers take advantage of the interrelations of labels. The result is that, with quite narrow intervals, i...

  3. Optimal interval for major maintenance actions in electricity distribution networks

    Energy Technology Data Exchange (ETDEWEB)

    Louit, Darko; Pascual, Rodrigo [Centro de Mineria, Pontificia Universidad Catolica de Chile, Av. Vicuna MacKenna, 4860 Santiago (Chile); Banjevic, Dragan [Centre for Maintenance Optimization and Reliability Engineering, University of Toronto, 5 King' s College Rd., Toronto, Ontario (Canada)

    2009-09-15

    Many systems require the periodic undertaking of major (preventive) maintenance actions (MMAs) such as overhauls in mechanical equipment, reconditioning of train lines, resurfacing of roads, etc. In the long term, these actions contribute to achieving a lower rate of occurrence of failures, though in many cases they increase the intensity of the failure process shortly after performed, resulting in a non-monotonic trend for failure intensity. Also, in the special case of distributed assets such as communications and energy networks, pipelines, etc., it is likely that the maintenance action takes place sequentially over an extended period of time, implying that different sections of the network underwent the MMAs at different periods. This forces the development of a model based on a relative time scale (i.e. time since last major maintenance event) and the combination of data from different sections of a grid, under a normalization scheme. Additionally, extended maintenance times and sequential execution of the MMAs make it difficult to identify failures occurring before and after the preventive maintenance action. This results in the loss of important information for the characterization of the failure process. A simple model is introduced to determine the optimal MMA interval considering such restrictions. Furthermore, a case study illustrates the optimal tree trimming interval around an electricity distribution network. (author)

  4. Physiological Adaptations to Sprint Interval Training with Matched Exercise Volume.

    Science.gov (United States)

    Lee, Chia-Lun; Hsu, Wei-Chieh; Cheng, Ching-Feng

    2017-01-01

    This study aimed to determine how high-intensity interval training (HIIT) protocols featuring matched times but distinct sprint durations affect cardiorespiratory and metabolic responses and performance. Thirty-eight recreationally active men (age 21 ± 2 yr) were assigned to one of three interval training groups: long-duration high-intensity (HIIT60s; 8 × 60 s at 85%-90% V˙O2max; 120-s recovery at 30% V˙O2max), short-duration high-intensity (HIIT10s; 48 × 10 s at 85%-90% V˙O2max; 20-s recovery at 30% V˙O2max), and control (regular physical activity without HIIT). Before and after a 4-wk training period (three sessions per week), participants performed graded exercise tests and repeated sprint tests, based on which their aerobic and anaerobic capacities were assessed. Skinfold thickness, blood, and metabolic responses were also measured before and after intervention. After the 4-wk training period, V˙O2max was significantly increased (P training (P 0.05), but testosterone concentration in the HIIT10s was higher after training than before (P performance and lower skinfold thickness in HIIT60s versus HIIT10s reflected similar adaptations, but the higher repeated sprint performance was observed only in responses to HIIT60s, which may elicit greater anaerobic adaptations.

  5. Risk based test interval and maintenance optimisation - Application and uses

    International Nuclear Information System (INIS)

    Sparre, E.

    1999-10-01

    The project is part of an IAEA co-ordinated Research Project (CRP) on 'Development of Methodologies for Optimisation of Surveillance Testing and Maintenance of Safety Related Equipment at NPPs'. The purpose of the project is to investigate the sensitivity of the results obtained when performing risk based optimisation of the technical specifications. Previous projects have shown that complete LPSA models can be created and that these models allow optimisation of technical specifications. However, these optimisations did not include any in depth check of the result sensitivity with regards to methods, model completeness etc. Four different test intervals have been investigated in this study. Aside from an original, nominal, optimisation a set of sensitivity analyses has been performed and the results from these analyses have been compared to the original optimisation. The analyses indicate that the result of an optimisation is rather stable. However, it is not possible to draw any certain conclusions without performing a number of sensitivity analyses. Significant differences in the optimisation result were discovered when analysing an alternative configuration. Also deterministic uncertainties seem to affect the result of an optimisation largely. The sensitivity of failure data uncertainties is important to investigate in detail since the methodology is based on the assumption that the unavailability of a component is dependent on the length of the test interval

  6. Lymphocyte subset reference intervals in blood donors from northeastern Brazil

    Directory of Open Access Journals (Sweden)

    ALEX J.L. TORRES

    2015-06-01

    Full Text Available The reference intervals for leukocytes and lymphocytes currently used by most clinical laboratories present limitations as they are primarily derived from individuals of North American and European origin. The objective this study was to determine reference values for peripheral blood B lymphocytes, T lymphocyte subsets (CD4+, CD8+, naïve, memory, regulatory, TCRαβ and TCRγδ+ and NK cells from blood donors in Salvador-Bahia, Brazil. Results: The proportion of included male subjects was 73.7% and the median ages of males (34 and females (35 were found to be similar. Absolute counts total lymphocytes subsets to both gender was 1,956 (1,060-4,186 cells and relative values 34%. The T CD4+ and T CD8+ lymphocytes relative values was 51% (20-62 and 24% (9-28, respectively. The most statistically significant finding observed was a higher percentage of B lymphocytes (p=0.03 in females. Commonly cited subset reference intervals were found to be consistent with values in several populations from different geographic areas.

  7. Spectral Methods Using Rational Basis Functions on an Infinite Interval

    Science.gov (United States)

    Boyd, John P.

    1987-03-01

    By using the map y = L cot( t) where L is a constant, differential equations on the interval yɛ [- ∞, ∞] can be transformed into tɛ [0, π] and solved by an ordinary Fourier series. In this article, earlier work by Grosch and Orszag ( J. Comput. Phys.25, 273 (1977)), Cain, Ferziger, and Reynolds ( J. Comput. Phys.56, 272 (1984)), and Boyd ( J. Comput. Phys.25, 43 (1982); 57, 454 (1985); SIAM J. Numer. Anal. (1987)) is extended in several ways. First, the series of orthogonal rational functions converge on the exterior of bipolar coordinate surfaces in the complex y-plane. Second, Galerkin's method will convert differential equations with polynomial or rational coefficients into banded matrix problems. Third, with orthogonal rational functions it is possible to obtain exponential convergence even for u( y) that asymptote to a constant although this behavior would wreck alternatives such as Hermite or sinc expansions. Fourth, boundary conditions are usually "natural" rather than "essential" in the sense that the singularities of the differential equation will force the numerical solution to have the correct behavior at infinity even if no constraints are imposed on the basis functions. Fifth, mapping a finite interval to an infinite one and then applying the rational Chebyshev functions gives an exponentially convergent method for functions with bounded endpoint singularities. These concepts are illustrated by five numerical examples.

  8. Estimation of the serial interval of pertussis in Dutch households.

    Science.gov (United States)

    Te Beest, Dennis E; Henderson, Donna; van der Maas, Nicoline A T; de Greeff, Sabine C; Wallinga, Jacco; Mooi, Frits R; van Boven, Michiel

    2014-06-01

    Increasing incidence has led to the re-appearance of pertussis as a public health problem in developed countries. Pertussis infection is usually mild in vaccinated children and adults, but it can be fatal in infants who are too young for effective vaccination (≤3 months). Tailoring of control strategies to prevent infection of the infant hinges on the availability of estimates of key epidemiological quantities. Here we estimate the serial interval of pertussis, i.e., the time between symptoms onset in a case and its infector, using data from a household-based study carried out in the Netherlands in 2007-2009. We use statistical methodology to tie infected persons to probable infector persons, and obtain statistically supported stratifications of the data by person-type (infant, mother, father, sibling). The analyses show that the mean serial interval is 20 days (95% CI: 16-23 days) when the mother is the infector of the infant, and 28 days (95% CI: 23-33 days) when the infector is the father or a sibling. These time frames offer opportunities for early mitigation of the consequences of infection of an infant once a case has been detected in a household. If preventive measures such as social distancing or antimicrobial treatment are taken promptly they could decrease the probability of infection of the infant. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

  9. Bridging the interval: theory and neurobiology of trace conditioning.

    Science.gov (United States)

    Raybuck, Jonathan D; Lattal, K Matthew

    2014-01-01

    An early finding in the behavioral analysis of learning was that conditioned responding weakens as the conditioned stimulus (CS) and unconditioned stimulus (US) are separated in time. This "trace" conditioning effect has been the focus of years of research in associative learning. Theoretical accounts of trace conditioning have focused on mechanisms that allow associative learning to occur across long intervals between the CS and US. These accounts have emphasized degraded contingency effects, timing mechanisms, and inhibitory learning. More recently, study of the neurobiology of trace conditioning has shown that even a short interval between the CS and US alters the circuitry recruited for learning. Here, we review some of the theoretical and neurobiological mechanisms underlying trace conditioning with an emphasis on recent studies of trace fear conditioning. Findings across many studies have implications not just for how we think about time and conditioning, but also for how we conceptualize fear conditioning in general, suggesting that circuitry beyond the usual suspects needs to be incorporated into current thinking about fear, learning, and anxiety. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Running interval training and estimated plasma-volume variation.

    Science.gov (United States)

    Ben Abderrahman, Abderraouf; Prioux, Jacques; Chamari, Karim; Ben Ounis, Omar; Tabka, Zouhair; Zouhal, Hassane

    2013-07-01

    The effect of endurance interval training (IT) on hematocrit (Ht), hemoglobin (Hb), and estimated plasma- volume variation (PVV) in response to maximal exercise was studied in 15 male subjects (21.1 ± 1.1 y; control group n = 6, and training group, n = 9). The training group participated in interval training 3 times a week for 7 wk. A maximal graded test (GXT) was performed to determine maximal aerobic power (MAP) and maximal aerobic speed (MAS) both before and after the training program. To determine Ht, Hb concentration, and lactate concentrations, blood was collected at rest, at the end of GXT, and after 10 and 30 min of recovery. MAP and MAS increased significantly (P training only in training group. Hematocrit determined at rest was significantly lower in the training group than in the control group after the training period (P training group (P training between PVV deter- mined at the end of the maximal test and MAS (r = .60, P training group. In conclusion, 7 wk of IT led to a significant increase in plasma volume that possibly contributed to the observed increase of aerobic fitness (MAP and MAS).

  11. Design of time interval generator based on hybrid counting method

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Yuan [State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Wang, Zhaoqi [State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Lu, Houbing [State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Hefei Electronic Engineering Institute, Hefei 230037 (China); Chen, Lian [State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Jin, Ge, E-mail: goldjin@ustc.edu.cn [State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2016-10-01

    Time Interval Generators (TIGs) are frequently used for the characterizations or timing operations of instruments in particle physics experiments. Though some “off-the-shelf” TIGs can be employed, the necessity of a custom test system or control system makes the TIGs, being implemented in a programmable device desirable. Nowadays, the feasibility of using Field Programmable Gate Arrays (FPGAs) to implement particle physics instrumentation has been validated in the design of Time-to-Digital Converters (TDCs) for precise time measurement. The FPGA-TDC technique is based on the architectures of Tapped Delay Line (TDL), whose delay cells are down to few tens of picosecond. In this case, FPGA-based TIGs with high delay step are preferable allowing the implementation of customized particle physics instrumentations and other utilities on the same FPGA device. A hybrid counting method for designing TIGs with both high resolution and wide range is presented in this paper. The combination of two different counting methods realizing an integratable TIG is described in detail. A specially designed multiplexer for tap selection is emphatically introduced. The special structure of the multiplexer is devised for minimizing the different additional delays caused by the unpredictable routings from different taps to the output. A Kintex-7 FPGA is used for the hybrid counting-based implementation of a TIG, providing a resolution up to 11 ps and an interval range up to 8 s.

  12. Evidence based exercise - clinical benefits of high intensity interval training.

    Science.gov (United States)

    Shiraev, Tim; Barclay, Gabriella

    2012-12-01

    Aerobic exercise has a marked impact on cardiovascular disease risk. Benefits include improved serum lipid profiles, blood pressure and inflammatory markers as well as reduced risk of stroke, acute coronary syndrome and overall cardiovascular mortality. Most exercise programs prescribed for fat reduction involve continuous, moderate aerobic exercise, as per Australian Heart Foundation clinical guidelines. This article describes the benefits of exercise for patients with cardiovascular and metabolic disease and details the numerous benefits of high intensity interval training (HIIT) in particular. Aerobic exercise has numerous benefits for high-risk populations and such benefits, especially weight loss, are amplified with HIIT. High intensity interval training involves repeatedly exercising at a high intensity for 30 seconds to several minutes, separated by 1-5 minutes of recovery (either no or low intensity exercise). HIT is associated with increased patient compliance and improved cardiovascular and metabolic outcomes and is suitable for implementation in both healthy and 'at risk' populations. Importantly, as some types of exercise are contraindicated in certain patient populations and HIIT is a complex concept for those unfamiliar to exercise, some patients may require specific assessment or instruction before commencing a HIIT program.

  13. Optimal Wind Power Uncertainty Intervals for Electricity Market Operation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ying; Zhou, Zhi; Botterud, Audun; Zhang, Kaifeng

    2018-01-01

    It is important to select an appropriate uncertainty level of the wind power forecast for power system scheduling and electricity market operation. Traditional methods hedge against a predefined level of wind power uncertainty, such as a specific confidence interval or uncertainty set, which leaves the questions of how to best select the appropriate uncertainty levels. To bridge this gap, this paper proposes a model to optimize the forecast uncertainty intervals of wind power for power system scheduling problems, with the aim of achieving the best trade-off between economics and reliability. Then we reformulate and linearize the models into a mixed integer linear programming (MILP) without strong assumptions on the shape of the probability distribution. In order to invest the impacts on cost, reliability, and prices in a electricity market, we apply the proposed model on a twosettlement electricity market based on a six-bus test system and on a power system representing the U.S. state of Illinois. The results show that the proposed method can not only help to balance the economics and reliability of the power system scheduling, but also help to stabilize the energy prices in electricity market operation.

  14. Covariate-adjusted confidence interval for the intraclass correlation coefficient.

    Science.gov (United States)

    Shoukri, Mohamed M; Donner, Allan; El-Dali, Abdelmoneim

    2013-09-01

    A crucial step in designing a new study is to estimate the required sample size. For a design involving cluster sampling, the appropriate sample size depends on the so-called design effect, which is a function of the average cluster size and the intracluster correlation coefficient (ICC). It is well-known that under the framework of hierarchical and generalized linear models, a reduction in residual error may be achieved by including risk factors as covariates. In this paper we show that the covariate design, indicating whether the covariates are measured at the cluster level or at the within-cluster subject level affects the estimation of the ICC, and hence the design effect. Therefore, the distinction between these two types of covariates should be made at the design stage. In this paper we use the nested-bootstrap method to assess the accuracy of the estimated ICC for continuous and binary response variables under different covariate structures. The codes of two SAS macros are made available by the authors for interested readers to facilitate the construction of confidence intervals for the ICC. Moreover, using Monte Carlo simulations we evaluate the relative efficiency of the estimators and evaluate the accuracy of the coverage probabilities of a 95% confidence interval on the population ICC. The methodology is illustrated using a published data set of blood pressure measurements taken on family members. © 2013. Published by Elsevier Inc. All rights reserved.

  15. [Concepts of inhibition in psychiatry].

    Science.gov (United States)

    Auroux, Y; Bourrat, M M; Brun, J P

    1978-01-01

    Following a historical approach, the authors first describe the original development of the concept of inhibition in neurophysiology and then analyze the subsequent adaptations made in psychiatry around such concept including those of: -- Pavlov, Hull, Watson and the behaviorists, -- Freud and the Freudian School, -- clinicians and psychopharmacologists. The concept of inhibition has thus various meanings in psychiatry. Although some unity is achieved on the semiological level, this aspect cannot explain the extent of the process.

  16. The impact of multiple irrelevant visual events at the same spatial location on inhibition.

    Science.gov (United States)

    Visser, Troy A W; Barnes, Daniel

    2009-02-01

    If an irrelevant visual event, such as a nonpredictive cue, is presented prior to a target, performance is impaired when the target appears at the cued location relative to when it is presented at an uncued location. This phenomenon, referred to as inhibition of return, can be found at multiple spatial locations when each is cued in succession. The present study examined the effect of successively cuing the same spatial location. Results suggested that additional inhibition occurred when more than one cue appeared at a single location at longer intercue intervals, but not at shorter intervals. These findings suggest that total inhibition to respond to targets at a spatial location reflects a summation of facilitatory and inhibitory factors generated by the presentation of each cue.

  17. Monte Carlo simulation of parameter confidence intervals for non-linear regression analysis of biological data using Microsoft Excel.

    Science.gov (United States)

    Lambert, Ronald J W; Mytilinaios, Ioannis; Maitland, Luke; Brown, Angus M

    2012-08-01

    This study describes a method to obtain parameter confidence intervals from the fitting of non-linear functions to experimental data, using the SOLVER and Analysis ToolPaK Add-In of the Microsoft Excel spreadsheet. Previously we have shown that Excel can fit complex multiple functions to biological data, obtaining values equivalent to those returned by more specialized statistical or mathematical software. However, a disadvantage of using the Excel method was the inability to return confidence intervals for the computed parameters or the correlations between them. Using a simple Monte-Carlo procedure within the Excel spreadsheet (without recourse to programming), SOLVER can provide parameter estimates (up to 200 at a time) for multiple 'virtual' data sets, from which the required confidence intervals and correlation coefficients can be obtained. The general utility of the method is exemplified by applying it to the analysis of the growth of Listeria monocytogenes, the growth inhibition of Pseudomonas aeruginosa by chlorhexidine and the further analysis of the electrophysiological data from the compound action potential of the rodent optic nerve. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  18. Bootstrap Confidence Intervals for Ordinary Least Squares Factor Loadings and Correlations in Exploratory Factor Analysis

    Science.gov (United States)

    Zhang, Guangjian; Preacher, Kristopher J.; Luo, Shanhong

    2010-01-01

    This article is concerned with using the bootstrap to assign confidence intervals for rotated factor loadings and factor correlations in ordinary least squares exploratory factor analysis. Coverage performances of "SE"-based intervals, percentile intervals, bias-corrected percentile intervals, bias-corrected accelerated percentile…

  19. The Lattice of Fuzzy Intervals and Sufficient Conditions for its Distributivity

    OpenAIRE

    Kehagias, Ath.

    2002-01-01

    Given a reference lattice, we define fuzzy intervals to be the fuzzy sets such that their p-cuts are crisp closed intervals. We show that: given a complete reference lattice, the collection of its fuzzy intervals is a complete lattice. Furthermore we show that: if the reference lattice is completely distributive then the lattice of its fuzzy intervals is distributive.

  20. An Introduction to Confidence Intervals for Both Statistical Estimates and Effect Sizes.

    Science.gov (United States)

    Capraro, Mary Margaret

    This paper summarizes methods of estimating confidence intervals, including classical intervals and intervals for effect sizes. The recent American Psychological Association (APA) Task Force on Statistical Inference report suggested that confidence intervals should always be reported, and the fifth edition of the APA "Publication Manual"…