Cosmic Rays in Intermittent Magnetic Fields

International Nuclear Information System (INIS)

Shukurov, Anvar; Seta, Amit; Bushby, Paul J.; Wood, Toby S.; Snodin, Andrew P.

2017-01-01

The propagation of cosmic rays in turbulent magnetic fields is a diffusive process driven by the scattering of the charged particles by random magnetic fluctuations. Such fields are usually highly intermittent, consisting of intense magnetic filaments and ribbons surrounded by weaker, unstructured fluctuations. Studies of cosmic-ray propagation have largely overlooked intermittency, instead adopting Gaussian random magnetic fields. Using test particle simulations, we calculate cosmic-ray diffusivity in intermittent, dynamo-generated magnetic fields. The results are compared with those obtained from non-intermittent magnetic fields having identical power spectra. The presence of magnetic intermittency significantly enhances cosmic-ray diffusion over a wide range of particle energies. We demonstrate that the results can be interpreted in terms of a correlated random walk.

Cosmic Rays in Intermittent Magnetic Fields

Energy Technology Data Exchange (ETDEWEB)

Shukurov, Anvar; Seta, Amit; Bushby, Paul J.; Wood, Toby S. [School of Mathematics and Statistics, Newcastle University, Newcastle Upon Tyne NE1 7RU (United Kingdom); Snodin, Andrew P., E-mail: a.seta1@ncl.ac.uk, E-mail: amitseta90@gmail.com [Department of Mathematics, Faculty of Applied Science, King Mongkut’s University of Technology North Bangkok, Bangkok 10800 (Thailand)

2017-04-10

The propagation of cosmic rays in turbulent magnetic fields is a diffusive process driven by the scattering of the charged particles by random magnetic fluctuations. Such fields are usually highly intermittent, consisting of intense magnetic filaments and ribbons surrounded by weaker, unstructured fluctuations. Studies of cosmic-ray propagation have largely overlooked intermittency, instead adopting Gaussian random magnetic fields. Using test particle simulations, we calculate cosmic-ray diffusivity in intermittent, dynamo-generated magnetic fields. The results are compared with those obtained from non-intermittent magnetic fields having identical power spectra. The presence of magnetic intermittency significantly enhances cosmic-ray diffusion over a wide range of particle energies. We demonstrate that the results can be interpreted in terms of a correlated random walk.

Cognitive-Behavioral Therapy for Intermittent Explosive Disorder: A Pilot Randomized Clinical Trial

Science.gov (United States)

McCloskey, Michael S.; Noblett, Kurtis L.; Deffenbacher, Jerry L.; Gollan, Jackie K.; Coccaro, Emil F.

2008-01-01

No randomized clinical trials have evaluated the efficacy of psychotherapy for intermittent explosive disorder (IED). In the present study, the authors tested the efficacy of 12-week group and individual cognitive-behavioral therapies (adapted from J. L. Deffenbacher & M. McKay, 2000) by comparing them with a wait-list control in a randomized…

Intermittent exploration on a scale-free network

International Nuclear Information System (INIS)

Ramezanpour, A

2007-02-01

We study an intermittent random walk on a random network of scale-free degree distribution. The walk is a combination of simple random walks of duration t w and random long-range jumps. While the time the walker needs to cover all the nodes increases with t w , the corresponding time for the edges displays a non monotonic behavior with a minimum for some nontrivial value of t w . This is a heterogeneity-induced effect that is not observed in homogeneous small-world networks. The optimal t w increases with the degree of assortativity in the network. Depending on the nature of degree correlations and the elapsed time the walker finds an over/underestimate of the degree distribution exponent. (author)

Han's model parameters for microalgae grown under intermittent illumination: Determined using particle swarm optimization.

Science.gov (United States)

Pozzobon, Victor; Perre, Patrick

2018-01-21

This work provides a model and the associated set of parameters allowing for microalgae population growth computation under intermittent lightning. Han's model is coupled with a simple microalgae growth model to yield a relationship between illumination and population growth. The model parameters were obtained by fitting a dataset available in literature using Particle Swarm Optimization method. In their work, authors grew microalgae in excess of nutrients under flashing conditions. Light/dark cycles used for these experimentations are quite close to those found in photobioreactor, i.e. ranging from several seconds to one minute. In this work, in addition to producing the set of parameters, Particle Swarm Optimization robustness was assessed. To do so, two different swarm initialization techniques were used, i.e. uniform and random distribution throughout the search-space. Both yielded the same results. In addition, swarm distribution analysis reveals that the swarm converges to a unique minimum. Thus, the produced set of parameters can be trustfully used to link light intensity to population growth rate. Furthermore, the set is capable to describe photodamages effects on population growth. Hence, accounting for light overexposure effect on algal growth. Copyright © 2017 Elsevier Ltd. All rights reserved.

Stabilization of microgrid with intermittent renewable energy sources by SMES with optimal coil size

International Nuclear Information System (INIS)

Saejia, M.; Ngamroo, I.

2011-01-01

A controller design of a superconducting magnetic energy storage unit is proposed. The structure of a power controller is the practical proportional-integral (PI). The PI parameters and coil size are tuned by a particle swarm optimization. The proposed method is able to effectively alleviate power fluctuations. It is well known that the superconducting coil is the vital part of a superconducting magnetic energy storage (SMES) unit. This paper deals with the power controller design of a SMES unit with an optimal coil size for stabilization of an isolated microgrid. The study microgrid consists of renewable energy sources with intermittent power outputs i.e., wind and photovoltaic. Since power generations from such renewable sources are unpredictable and variable, these result in power fluctuations in a microgrid. To stabilize power fluctuations, a SMES unit with a fast control of active and reactive power can be applied. The structure of a power controller is the practical proportional-integral (PI). Based on the minimization of the variance of power fluctuations from renewable sources as well as the initial stored energy of SMES, the optimal PI parameters and coil size are automatically and simultaneously tuned by a particle swarm optimization. Simulation studies show that the proposed SMES controller with an optimal coil size is able to effectively alleviate power fluctuations under various power patterns from intermittent renewable sources.

Stabilization of microgrid with intermittent renewable energy sources by SMES with optimal coil size

Energy Technology Data Exchange (ETDEWEB)

Saejia, M., E-mail: samongkol@gmail.com [School of Electrical Engineering, Faculty of Engineering, King Mongkut' s Institute of Technology Ladkrabang, Bangkok 10520 (Thailand); Ngamroo, I. [School of Electrical Engineering, Faculty of Engineering, King Mongkut' s Institute of Technology Ladkrabang, Bangkok 10520 (Thailand)

2011-11-15

A controller design of a superconducting magnetic energy storage unit is proposed. The structure of a power controller is the practical proportional-integral (PI). The PI parameters and coil size are tuned by a particle swarm optimization. The proposed method is able to effectively alleviate power fluctuations. It is well known that the superconducting coil is the vital part of a superconducting magnetic energy storage (SMES) unit. This paper deals with the power controller design of a SMES unit with an optimal coil size for stabilization of an isolated microgrid. The study microgrid consists of renewable energy sources with intermittent power outputs i.e., wind and photovoltaic. Since power generations from such renewable sources are unpredictable and variable, these result in power fluctuations in a microgrid. To stabilize power fluctuations, a SMES unit with a fast control of active and reactive power can be applied. The structure of a power controller is the practical proportional-integral (PI). Based on the minimization of the variance of power fluctuations from renewable sources as well as the initial stored energy of SMES, the optimal PI parameters and coil size are automatically and simultaneously tuned by a particle swarm optimization. Simulation studies show that the proposed SMES controller with an optimal coil size is able to effectively alleviate power fluctuations under various power patterns from intermittent renewable sources.

Control of spatio-temporal on-off intermittency in random driving diffusively coupled map lattices

International Nuclear Information System (INIS)

Ziabakhsh Deilami, M.; Rahmani Cherati, Z.; Jahed Motlagh, M.R.

2009-01-01

In this paper, we propose feedback methods for controlling spatio-temporal on-off intermittency which is an aperiodic switching between an 'off' state and an 'on' state. Diffusively coupled map lattice with spatially non-uniform random driving is used for showing spatio-temporal on-off intermittency. For this purpose, we apply three different feedbacks. First, we use a linear feedback which is a simple method but has a long transient time. To overcome this problem, two nonlinear feedbacks based on prediction strategy are proposed. An important advantage of the methods is that the feedback signal is vanished when control is realized. Simulation results show that all methods have suppressed the chaotic behavior.

Intermittent vs. Continuous Anticoagulation theRapy in patiEnts with Atrial Fibrillation (iCARE-AF): a randomized pilot study.

Science.gov (United States)

Stavrakis, Stavros; Stoner, Julie A; Kardokus, Joel; Garabelli, Paul J; Po, Sunny S; Lazzara, Ralph

2017-01-01

We hypothesized that intermittent anticoagulation based on daily rhythm monitoring using the novel oral anticoagulants (NOACs) is feasible and safe among patients with paroxysmal atrial fibrillation (AF). Patients with paroxysmal AF and ≥1 risk factors for stroke were randomized to either intermittent or continuous anticoagulation. Those in the intermittent group were instructed to transmit a daily ECG using an iPhone-based rhythm monitoring device. If AF was detected, patients received one of the NOACs for 48 h-1 week. Patients who failed to transmit an ECG for three consecutive days or more than 7 days total were crossed over to continuous anticoagulation. Patients in the continuous group received one of the NOACs. Fifty-eight patients were randomized to either intermittent (n = 29) or continuous anticoagulation (n = 29). Over a median follow-up of 20 months, 20 patients in the intermittent group failed to submit a daily ECG at least once (median three failed submissions). Four patients (14 %) crossed over to continuous anticoagulation due to failure to submit an ECG for three consecutive days. One stroke (continuous group) occurred during the study. Major bleeding occurred in two patients in the continuous and one patient in the intermittent group, after crossing over to continuous anticoagulation. In a prespecified per-protocol analysis, gastrointestinal bleeding was more frequent in the continuous group (16 vs. 0 %; p = 0.047). Intermittent anticoagulation based on daily rhythm monitoring is feasible and may decrease bleeding in low-risk patients with paroxysmal AF. A larger trial, adequately powered to detect clinical outcomes, is warranted.

Random intermittent search and the tug-of-war model of motor-driven transport

International Nuclear Information System (INIS)

Newby, Jay; Bressloff, Paul C

2010-01-01

We formulate the 'tug-of-war' model of microtubule cargo transport by multiple molecular motors as an intermittent random search for a hidden target. A motor complex consisting of multiple molecular motors with opposing directional preference is modeled using a discrete Markov process. The motors randomly pull each other off of the microtubule so that the state of the motor complex is determined by the number of bound motors. The tug-of-war model prescribes the state transition rates and corresponding cargo velocities in terms of experimentally measured physical parameters. We add space to the resulting Chapman–Kolmogorov (CK) equation so that we can consider delivery of the cargo to a hidden target at an unknown location along the microtubule track. The target represents some subcellular compartment such as a synapse in a neuron's dendrites, and target delivery is modeled as a simple absorption process. Using a quasi-steady-state (QSS) reduction technique we calculate analytical approximations of the mean first passage time (MFPT) to find the target. We show that there exists an optimal adenosine triphosphate (ATP) concentration that minimizes the MFPT for two different cases: (i) the motor complex is composed of equal numbers of kinesin motors bound to two different microtubules (symmetric tug-of-war model) and (ii) the motor complex is composed of different numbers of kinesin and dynein motors bound to a single microtubule (asymmetric tug-of-war model)

Random intermittent search and the tug-of-war model of motor-driven transport

Science.gov (United States)

Newby, Jay; Bressloff, Paul C.

2010-04-01

We formulate the 'tug-of-war' model of microtubule cargo transport by multiple molecular motors as an intermittent random search for a hidden target. A motor complex consisting of multiple molecular motors with opposing directional preference is modeled using a discrete Markov process. The motors randomly pull each other off of the microtubule so that the state of the motor complex is determined by the number of bound motors. The tug-of-war model prescribes the state transition rates and corresponding cargo velocities in terms of experimentally measured physical parameters. We add space to the resulting Chapman-Kolmogorov (CK) equation so that we can consider delivery of the cargo to a hidden target at an unknown location along the microtubule track. The target represents some subcellular compartment such as a synapse in a neuron's dendrites, and target delivery is modeled as a simple absorption process. Using a quasi-steady-state (QSS) reduction technique we calculate analytical approximations of the mean first passage time (MFPT) to find the target. We show that there exists an optimal adenosine triphosphate (ATP) concentration that minimizes the MFPT for two different cases: (i) the motor complex is composed of equal numbers of kinesin motors bound to two different microtubules (symmetric tug-of-war model) and (ii) the motor complex is composed of different numbers of kinesin and dynein motors bound to a single microtubule (asymmetric tug-of-war model).

Random intermittent search and the tug-of-war model of motor-driven transport

KAUST Repository

Newby, Jay

2010-04-16

We formulate the \\'tug-of-war\\' model of microtubule cargo transport by multiple molecular motors as an intermittent random search for a hidden target. A motor complex consisting of multiple molecular motors with opposing directional preference is modeled using a discrete Markov process. The motors randomly pull each other off of the microtubule so that the state of the motor complex is determined by the number of bound motors. The tug-of-war model prescribes the state transition rates and corresponding cargo velocities in terms of experimentally measured physical parameters. We add space to the resulting Chapman-Kolmogorov (CK) equation so that we can consider delivery of the cargo to a hidden target at an unknown location along the microtubule track. The target represents some subcellular compartment such as a synapse in a neuron\\'s dendrites, and target delivery is modeled as a simple absorption process. Using a quasi-steady-state (QSS) reduction technique we calculate analytical approximations of the mean first passage time (MFPT) to find the target. We show that there exists an optimal adenosine triphosphate (ATP) concentration that minimizes the MFPT for two different cases: (i) the motor complex is composed of equal numbers of kinesin motors bound to two different microtubules (symmetric tug-of-war model) and (ii) the motor complex is composed of different numbers of kinesin and dynein motors bound to a single microtubule (asymmetric tug-of-war model). © 2010 IOP Publishing Ltd.

Random intermittent search and the tug-of-war model of motor-driven transport

KAUST Repository

Newby, Jay; Bressloff, Paul C

2010-01-01

We formulate the 'tug-of-war' model of microtubule cargo transport by multiple molecular motors as an intermittent random search for a hidden target. A motor complex consisting of multiple molecular motors with opposing directional preference is modeled using a discrete Markov process. The motors randomly pull each other off of the microtubule so that the state of the motor complex is determined by the number of bound motors. The tug-of-war model prescribes the state transition rates and corresponding cargo velocities in terms of experimentally measured physical parameters. We add space to the resulting Chapman-Kolmogorov (CK) equation so that we can consider delivery of the cargo to a hidden target at an unknown location along the microtubule track. The target represents some subcellular compartment such as a synapse in a neuron's dendrites, and target delivery is modeled as a simple absorption process. Using a quasi-steady-state (QSS) reduction technique we calculate analytical approximations of the mean first passage time (MFPT) to find the target. We show that there exists an optimal adenosine triphosphate (ATP) concentration that minimizes the MFPT for two different cases: (i) the motor complex is composed of equal numbers of kinesin motors bound to two different microtubules (symmetric tug-of-war model) and (ii) the motor complex is composed of different numbers of kinesin and dynein motors bound to a single microtubule (asymmetric tug-of-war model). © 2010 IOP Publishing Ltd.

How does network design constrain optimal operation of intermittent water supply?

Science.gov (United States)

Lieb, Anna; Wilkening, Jon; Rycroft, Chris

2015-11-01

Urban water distribution systems do not always supply water continuously or reliably. As pipes fill and empty, pressure transients may contribute to degraded infrastructure and poor water quality. To help understand and manage this undesirable side effect of intermittent water supply--a phenomenon affecting hundreds of millions of people in cities around the world--we study the relative contributions of fixed versus dynamic properties of the network. Using a dynamical model of unsteady transition pipe flow, we study how different elements of network design, such as network geometry, pipe material, and pipe slope, contribute to undesirable pressure transients. Using an optimization framework, we then investigate to what extent network operation decisions such as supply timing and inflow rate may mitigate these effects. We characterize some aspects of network design that make them more or less amenable to operational optimization.

A stochastic model for intermittent search strategies

International Nuclear Information System (INIS)

Benichou, O; Coppey, M; Moreau, M; Suet, P H; Voituriez, R

2005-01-01

It is often necessary, in scientific or everyday life problems, to find a randomly hidden target. What is then the optimal strategy to reach it as rapidly as possible? In this article, we develop a stochastic theory for intermittent search behaviours, which are often observed: the searcher alternates phases of intensive search and slow motion with fast displacements. The first results of this theory have already been announced recently. Here we provide a detailed presentation of the theory, as well as the full derivation of the results. Furthermore, we explicitly discuss the minimization of the time needed to find the target

Does prolonged β-lactam infusions improve clinical outcomes compared to intermittent infusions? A meta-analysis and systematic review of randomized, controlled trials

Directory of Open Access Journals (Sweden)

Van Arendonk Kyle J

2011-06-01

Full Text Available Abstract Background The emergence of multi-drug resistant Gram-negatives (MDRGNs coupled with an alarming scarcity of new antibiotics has forced the optimization of the therapeutic potential of available antibiotics. To exploit the time above the minimum inhibitory concentration mechanism of β-lactams, prolonging their infusion may improve outcomes. The primary objective of this meta-analysis was to determine if prolonged β-lactam infusion resulted in decreased mortality and improved clinical cure compared to intermittent β-lactam infusion. Methods Relevant studies were identified from searches of MEDLINE, EMBASE, and CENTRAL. Heterogeneity was assessed qualitatively, in addition to I2 and Chi-square statistics. Pooled relative risks (RR and 95% confidence intervals (CI were calculated using Mantel-Haenszel random-effects models. Results Fourteen randomized controlled trials (RCTs were included. Prolonged infusion β-lactams were not associated with decreased mortality (n= 982; RR 0.92; 95% CI:0.61-1.37 or clinical cure (n = 1380; RR 1.00 95% CI:0.94-1.06 compared to intermittent infusions. Subgroup analysis for β-lactam subclasses and equivalent total daily β-lactam doses yielded similar results. Most studies had notable methodological flaws. Conclusions No clinical advantage was observed for prolonged infusion β-lactams. The limited number of studies with MDRGNs precluded evaluation of prolonged infusion of β-lactams for this subgroup. A large, multicenter RCT with critically ill patients infected with MDRGNs is needed.

Randomized double-blind placebo-controlled crossover study of caffeine in patients with intermittent claudication.

Science.gov (United States)

Momsen, A H; Jensen, M B; Norager, C B; Madsen, M R; Vestersgaard-Andersen, T; Lindholt, J S

2010-10-01

Intermittent claudication is a disabling symptom of peripheral arterial disease for which few medical treatments are available. This study investigated the effect of caffeine on physical capacity in patients with intermittent claudication. This randomized double-blind placebo-controlled crossover study included 88 patients recruited by surgeons from outpatient clinics. The participants abstained from caffeine for 48 h before each test and then received either a placebo or oral caffeine (6 mg/kg). After 75 min, pain-free and maximal walking distance on a treadmill, perceived pain, reaction times, postural stability, maximal isometric knee extension strength, submaximal knee extension endurance and cognitive function were measured. The analysis was by intention to treat. Caffeine increased the pain-free walking distance by 20.0 (95 per cent confidence interval 3.7 to 38.8) per cent (P = 0.014), maximal walking distance by 26.6 (12.1 to 43.0) per cent (P postural stability was reduced significantly, by 22.1 (11.7 to 33.4) per cent with eyes open (P < 0.001) and by 21.8 (7.6 to 37.8) per cent with eyes closed (P = 0.002). Neither reaction time nor cognition was affected. In patients with moderate intermittent claudication, caffeine increased walking distance, maximal strength and endurance, but affected balance adversely.

[Effects of intermittent hypoxia on the responses of genioglossus motor cortex to transcranial magnetic stimulation in rats].

Science.gov (United States)

Li, Ting; Wang, Wei; Kong, De-lei; Su, Jiao; Kang, Jian

2012-04-01

To explore the influence of intermittent hypoxia on the responses of genioglossus motor cortex to transcranial magnetic stimulation. Male Sprague-Dawley rats were randomly divided into a control group and a chronic intermittent hypoxia group. Transcranial magnetic stimulation was applied in genioglossus motor cortex of the 2 groups. The responses of transcranial magnetic stimulation were recorded and analyzed by single factor analysis of variance. The anterolateral area provided an optimal motor evoked potential response to transcranial magnetic stimulation in the genioglossus motor cortex of the rats. Genioglossus motor evoked potential latency and amplitude were significantly modified by intermittent hypoxic exposure, with a significant decrease in latency (F = 3.294, P motor cortex in rats.

The Random Telegraph Signal Behavior of Intermittently Stuck Bits in SDRAMs

Science.gov (United States)

Chugg, Andrew Michael; Burnell, Andrew J.; Duncan, Peter H.; Parker, Sarah; Ward, Jonathan J.

2009-12-01

This paper reports behavior analogous to the Random Telegraph Signal (RTS) seen in the leakage currents from radiation induced hot pixels in Charge Coupled Devices (CCDs), but in the context of stuck bits in Synchronous Dynamic Random Access Memories (SDRAMs). Our analysis suggests that pseudo-random sticking and unsticking of the SDRAM bits is due to thermally induced fluctuations in leakage current through displacement damage complexes in depletion regions that were created by high-energy neutron and proton interactions. It is shown that the number of observed stuck bits increases exponentially with temperature, due to the general increase in the leakage currents through the damage centers with temperature. Nevertheless, some stuck bits are seen to pseudo-randomly stick and unstick in the context of a continuously rising trend of temperature, thus demonstrating that their damage centers can exist in multiple widely spaced, discrete levels of leakage current, which is highly consistent with RTS. This implies that these intermittently stuck bits (ISBs) are a displacement damage phenomenon and are unrelated to microdose issues, which is confirmed by the observation that they also occur in unbiased irradiation. Finally, we note that observed variations in the periodicity of the sticking and unsticking behavior on several timescales is most readily explained by multiple leakage current pathways through displacement damage complexes spontaneously and independently opening and closing under the influence of thermal vibrations.

Optimal Intermittent Dose Schedules for Chemotherapy Using Genetic Algorithm

Directory of Open Access Journals (Sweden)

Nadia ALAM

2013-08-01

Full Text Available In this paper, a design method for optimal cancer chemotherapy schedules via genetic algorithm (GA is presented. The design targets the key objective of chemotherapy to minimize the size of cancer tumor after a predefined time with keeping toxic side effects in limit. This is a difficult target to achieve using conventional clinical methods due to poor therapeutic indices of existing anti-cancer drugs. Moreover, there are clinical limitations in treatment administration to maintain continuous treatment. Besides, carefully decided rest periods are recommended to for patient’s comfort. Three intermittent drug scheduling schemes are presented in this paper where GA is used to optimize the dose quantities and timings by satisfying several treatment constraints. All three schemes are found to be effective in total elimination of cancer tumor after an agreed treatment length. The number of cancer cells is found zero at the end of the treatment for all three cases with tolerable toxicity. Finally, two of the schemes, “Fixed interval variable dose (FIVD and “Periodic dose” that are periodic in characteristic have been emphasized due to their additional simplicity in administration along with friendliness to patients. responses to the designed treatment schedules. Therefore the proposed design method is capable of planning effective, simple, patient friendly and acceptable chemotherapy schedules.

Intermittency in the particle production and in the nuclear multifragmentation

International Nuclear Information System (INIS)

Bozek, P.; Ploszajczak, M.

1991-01-01

Intermittency is a manifestation of scale invariance and randomness in physical systems. Intermittency in relativistic heavy-ion collisions and, in particular, the projectile dependence, multiplicity dependence and source-size dependence are discussed in the frame of the model of spatio-temporal intermittency. Moreover, recent theoretical results in intermittency studies of the nuclear multifragmentation are presented. (author) 35 refs., 4 figs., 1 tab

Effect of intermittent versus continuous energy restriction on weight loss, maintenance and cardiometabolic risk: A randomized 1-year trial.

Science.gov (United States)

Sundfør, T M; Svendsen, M; Tonstad, S

2018-07-01

Long-term adherence to conventional weight-loss diets is limited while intermittent fasting has risen in popularity. We compared the effects of intermittent versus continuous energy restriction on weight loss, maintenance and cardiometabolic risk factors in adults with abdominal obesity and ≥1 additional component of metabolic syndrome. In total 112 participants (men [50%] and women [50%]) aged 21-70 years with BMI 30-45 kg/m 2 (mean 35.2 [SD 3.7]) were randomized to intermittent or continuous energy restriction. A 6-month weight-loss phase including 10 visits with dieticians was followed by a 6-month maintenance phase without additional face-to-face counselling. The intermittent energy restriction group was advised to consume 400/600 kcal (female/male) on two non-consecutive days. Based on dietary records both groups reduced energy intake by ∼26-28%. Weight loss was similar among participants in the intermittent and continuous energy restriction groups (8.0 kg [SD 6.5] versus 9.0 kg [SD 7.1]; p = 0.6). There were favorable improvements in waist circumference, blood pressure, triglycerides and HDL-cholesterol with no difference between groups. Weight regain was minimal and similar between the intermittent and continuous energy restriction groups (1.1 kg [SD 3.8] versus 0.4 kg [SD 4.0]; p = 0.6). Intermittent restriction participants reported higher hunger scores than continuous restriction participants on a subjective numeric rating scale (4.7 [SD 2.2] vs 3.6 [SD 2.2]; p = 0.002). Both intermittent and continuous energy restriction resulted in similar weight loss, maintenance and improvements in cardiovascular risk factors after one year. However, feelings of hunger may be more pronounced during intermittent energy restriction. www.clinicaltrials.govNCT02480504. Copyright © 2018 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine

CONDITIONED ANALYSIS OF HIGH-LATITUDE SOLAR WIND INTERMITTENCY

International Nuclear Information System (INIS)

D'Amicis, R.; Consolini, G.; Bavassano, B.; Bruno, R.

2012-01-01

The solar wind is a turbulent medium displaying intermittency. Its intermittent features have been widely documented and studied, showing how the intermittent character is different in fast and slow wind. In this paper, a statistical conditioned analysis of the solar wind intermittency for a period of high-latitude fast solar wind is presented. In particular, the intermittent features are investigated as a function of the Alfvénic degree of fluctuations at a given scale. The results show that the main contribution to solar wind intermittency is due to non-Alfvénic structures, while Alfvénic increments are found to be characterized by a smaller level of intermittency than the previous ones. Furthermore, the lifetime statistics of Alfvénic periods are discussed in terms of a multiscale texture of randomly oriented flux tubes.

Intermittent or daily montelukast versus placebo for episodic asthma in children.

Science.gov (United States)

Valovirta, Erkka; Boza, Maria L; Robertson, Colin F; Verbruggen, Nadia; Smugar, Steven S; Nelsen, Linda M; Knorr, Barbara A; Reiss, Theodore F; Philip, George; Gurner, Deborah M

2011-06-01

No standard, optimal treatment exists for severe intermittent (ie, episodic) asthma in children. However, evidence suggests that both daily and episode-driven montelukast are effective for this phenotype. To assess the regimen-related efficacy of montelukast in treating pediatric episodic asthma. A multicenter, randomized, double-blind, double-dummy, parallel-group, 52-week study was performed in children 6 months to 5 years of age comparing placebo with two regimens of montelukast 4 mg: (1) daily; or (2) episode-driven for 12 days beginning with signs/symptoms consistent with imminent cold or breathing problem. The main outcome measure was the number of asthma episodes (symptoms requiring treatment) culminating in an asthma attack (symptoms requiring physician visit, emergency room visit, corticosteroids, or hospitalization). Five hundred eighty-nine patients were randomized to daily montelukast, 591 to intermittent montelukast, and 591 to placebo. Compared with placebo, no significant difference was seen between daily montelukast (P = .510) or intermittent montelukast (P = .884) in the number of asthma episodes culminating in an asthma attack over 1 year. Daily montelukast reduced symptoms over the 12-day treatment period of asthma episodes compared with placebo (P = .045). Beta-agonist use was reduced with both daily (P = .048) and intermittent montelukast (P = .028) compared with placebo. However, because of prespecified rules for multiplicity adjustments (requiring a positive primary endpoint), statistical significance for secondary endpoints cannot be concluded. All treatments were well tolerated. Montelukast did not reduce the number of asthma episodes culminating in an asthma attack over 1 year in children 6 months to 5 years of age, although numerical improvements occurred in some endpoints. Copyright © 2011 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Randomized double-blind placebo-controlled crossover study of caffeine in patients with intermittent claudication

DEFF Research Database (Denmark)

Momsen, A H; Jensen, M B; Norager, C B

2010-01-01

Intermittent claudication is a disabling symptom of peripheral arterial disease for which few medical treatments are available. This study investigated the effect of caffeine on physical capacity in patients with intermittent claudication.......Intermittent claudication is a disabling symptom of peripheral arterial disease for which few medical treatments are available. This study investigated the effect of caffeine on physical capacity in patients with intermittent claudication....

Intermittent Smoothing Approaches for Wind Power Output: A Review

Directory of Open Access Journals (Sweden)

Muhammad Jabir

2017-10-01

Full Text Available Wind energy is one of the most common types of renewable energy resource. Due to its sustainability and environmental benefits, it is an emerging source for electric power generation. Rapid and random changes of wind speed makes it an irregular and inconsistent power source when connected to the grid, causing different technical problems in protection, power quality and generation dispatch control. Due to these problems, effective intermittent smoothing approaches for wind power output are crucially needed to minimize such problems. This paper reviews various intermittent smoothing approaches used in smoothing the output power fluctuations caused by wind energy. Problems associated with the inclusion of wind energy resources to grid are also briefly reviewed. From this review, it has been found that battery energy storage system is the most suitable and effective smoothing approach, provided that an effective control strategy is available for optimal utilization of battery energy system. This paper further demonstrates different control strategies built for battery energy storage system to obtain the smooth output wind power.

Efficacy of continuous versus intermittent subglottic secretion drainage in preventing ventilator-associated pneumonia in patients requiring mechanical ventilation: A single-center randomized controlled trial.

Science.gov (United States)

Fujimoto, Hiroko; Yamaguchi, Osamu; Hayami, Hajime; Shimosaka, Mika; Tsuboi, Sayaka; Sato, Mitsunori; Takebayashi, Shigeo; Morita, Satoshi; Saito, Mari; Goto, Takahisa; Kurahashi, Kiyoyasu

2018-03-23

Aspiration of subglottic secretion is a widely used intervention to prevent ventilator-associated pneumonia (VAP). This study aimed to compare the efficacy of continuous and intermittent subglottic secretion drainage (SSD) in preventing VAP. A single-center randomized controlled trial was conducted on adult postoperative patients who were expected to undergo mechanical ventilation for more than 48 hours. Primary outcome measure was incidence of VAP and secondary outcome measures were length of mechanical ventilation and intensive-care unit (ICU) stay. Fifty-nine patients received continuous SSD, while 60 patients received intermittent SSD. Of these 119 patients, 88 (74%) were excluded and 15 and 16 patients were allocated to receive continuous and intermittent SSD, respectively. VAP was detected in 4 (26.7%) and 7 (43.8%) patients in the continuous and intermittent groups, respectively, (p=0.320). The length of mechanical ventilation was significantly shorter (p=0.034) in the continuous group (99.5±47.1 h) than in the intermittent group (159.9±94.5 h). The length of ICU stay was also shorter (p=0.0097) in the continuous group (6.3±2.1 days) than the intermittent group (9.8±4.8 days). Although continuous SSD did not reduce the incidence of VAP, it reduced the length of mechanical ventilation and ICU stay when compared to intermittent SSD.

Degrees-of-Freedom of the MIMO Three-Way Channel with Node-Intermittency

KAUST Repository

Neu, Joachim

2017-08-28

The characterization of fundamental performance bounds of many-to-many communication systems in which participating nodes are active in an intermittent way is one of the major challenges in communication theory. In order to address this issue, we introduce the multiple-input multiple-output (MIMO) three-way channel (3WC) with an intermittent node and study its degrees-of-freedom (DoF) region and sum-DoF. We devise a non-adaptive encoding scheme based on zero-forcing, interference alignment and erasure coding, and show its DoF region (and thus sum-DoF) optimality for non-intermittent 3WCs and its sum-DoF optimality for (node-)intermittent 3WCs. However, we show by example that in general some DoF tuples in the intermittent 3WC can only be achieved by adaptive schemes, such as multi-hop or decode-forward relaying. This shows that non-adaptive encoding is sufficient for the non-intermittent 3WC and for the sum-DoF of intermittent 3WCs, but adaptive encoding is necessary for the DoF region of intermittent 3WCs. Our work contributes to a better understanding of the fundamental limits of multi-way communication systems with intermittency and the impact of adaptation therein.

Decoherence in optimized quantum random-walk search algorithm

International Nuclear Information System (INIS)

Zhang Yu-Chao; Bao Wan-Su; Wang Xiang; Fu Xiang-Qun

2015-01-01

This paper investigates the effects of decoherence generated by broken-link-type noise in the hypercube on an optimized quantum random-walk search algorithm. When the hypercube occurs with random broken links, the optimized quantum random-walk search algorithm with decoherence is depicted through defining the shift operator which includes the possibility of broken links. For a given database size, we obtain the maximum success rate of the algorithm and the required number of iterations through numerical simulations and analysis when the algorithm is in the presence of decoherence. Then the computational complexity of the algorithm with decoherence is obtained. The results show that the ultimate effect of broken-link-type decoherence on the optimized quantum random-walk search algorithm is negative. (paper)

Brownian Optimal Stopping and Random Walks

International Nuclear Information System (INIS)

Lamberton, D.

2002-01-01

One way to compute the value function of an optimal stopping problem along Brownian paths consists of approximating Brownian motion by a random walk. We derive error estimates for this type of approximation under various assumptions on the distribution of the approximating random walk

Effects of Intermittent Versus Continuous Walking on Distance Walked and Fatigue in Persons With Multiple Sclerosis: A Randomized Crossover Trial.

Science.gov (United States)

Karpatkin, Herb; Cohen, Evan T; Rzetelny, Adam; Parrott, J Scott; Breismeister, Breanne; Hartman, Ryan; Luu, Ronald; Napolione, Danielle

2015-07-01

Fatigue is a common, disabling symptom experienced by persons with multiple sclerosis (MS). Evidence shows that intermittent exercise is associated in improved performance and negligible fatigue. The purpose of this study was to examine whether subjects with MS walk greater distances with less fatigue under intermittent (INT) or continuous (CONT) walking condition. Twenty-seven subjects with MS (median Extended Disability Severity Scale 3.5, interquartile range 1.6) walked in the CONT (ie, 6 uninterrupted minutes) and INT (ie, three 2-minute walking bouts) conditions in a randomized crossover. Distance was measured for the entire 6-minute walking period and each 2-minute increment. Fatigue was measured as the difference in a visual analog scale of fatigue (ΔVAS-F) immediately preceding and following each trial. Participants walked greater distances in the INT condition compared to the CONT condition (P = 0.005). There was a significant interaction of walking condition and time (P walked in the INT condition changed across time. ΔVAS-F was significantly lower in the INT condition than in the CONT condition (P = 0.036). Subjects with MS walked farther, and with less fatigue, when walking intermittently rather than continuously. Persons with MS may be able to tolerate a greater dose of walking training if the walking bouts are intermittent. Further study to determine the benefits of a walking exercise program using intermittent walking is recommended.Video Abstract available for additional insights from the authors (Supplemental Digital Content 1, http://links.lww.com/JNPT/A103).

Safety of a New Compact Male Intermittent Catheter: Randomized, Cross-Over, Single-Blind Study in Healthy Male Volunteers

DEFF Research Database (Denmark)

Bagi, Per; Hannibalsen, Jane; Permild, Rikke

2011-01-01

in hematuria (p = 0.54) or discomfort/stinging/pain at first micturition (p = 0.56). During insertion, handling was easier (p = 0.0001) and touching the coating was necessary less often (2.2 vs. 81.3% of catheterizations; p catheter; it was preferred by nurses for 20 of 23......Introduction: A new compact male intermittent catheter was compared with a regular intermittent male catheter in terms of safety and acceptability. Methods: In this randomized, single-blind, cross-over study, healthy male volunteers were catheterized twice with a compact catheter and twice...... with a regular catheter. Results: 28 participants were enrolled. Mean ± SD discomfort (visual analogue scale; primary objective) was 2.25 ± 1.5 and 2.52 ± 1.8 for the compact and regular catheters, respectively (difference -0.27; 95% confidence interval -0.73 to 0.19); there was no significant difference...

Compensatory mechanisms activated with intermittent energy restriction: A randomized control trial.

Science.gov (United States)

Coutinho, Sílvia Ribeiro; Halset, Eline Holli; Gåsbakk, Sigrid; Rehfeld, Jens F; Kulseng, Bård; Truby, Helen; Martins, Cátia

2018-06-01

Strong compensatory responses, with reduced resting metabolic rate (RMR), increased exercise efficiency (ExEff) and appetite, are activated when weight loss (WL) is achieved with continuous energy restriction (CER), which try to restore energy balance. Intermittent energy restriction (IER), where short spells of energy restriction are interspaced by periods of habitual energy intake, may offer some protection in minimizing those responses. We aimed to compare the effect of IER versus CER on body composition and the compensatory responses induced by WL. 35 adults (age: 39 ± 9 y) with obesity (BMI: 36 ± 4 kg/m 2 ) were randomized to lose a similar weight with an IER (N = 18) or a CER (N = 17) diet over a 12 week period. Macronutrient composition and overall energy restriction (33% reduction) were similar between groups. Body weight/composition, RMR, fasting respiratory quotient (RQ), ExEff (10, 25, and 50 W), subjective appetite ratings (hunger, fullness, desire to eat, and prospective food consumption (PFC)), and appetite-regulating hormones (active ghrelin (AG), cholecystokinin (CCK), total peptide YY (PYY), active glucagon-like peptide-1 (GLP-1), and insulin) were measured before and after WL. Changes in body weight (≈12.5% WL) and composition were similar in both groups. Fasting RQ and ExEff at 10 W increased in both groups. Losing weight, either by IER or CER dieting, did not induce significant changes in subjective appetite ratings. RMR decreased and ExEff at 25 and 50 W increased (P intermittent, does not appear to modulate the compensatory mechanisms activated by weight loss. NCT02169778 (the study was registered in clinicaltrial.gov). Copyright © 2017 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Nonlinear system identification for prostate cancer and optimality of intermittent androgen suppression therapy.

Science.gov (United States)

Suzuki, Taiji; Aihara, Kazuyuki

2013-09-01

These days prostate cancer is one of the most common types of malignant neoplasm in men. Androgen ablation therapy (hormone therapy) has been shown to be effective for advanced prostate cancer. However, continuous hormone therapy often causes recurrence. This results from the progression of androgen-dependent cancer cells to androgen-independent cancer cells during the continuous hormone therapy. One possible method to prevent the progression to the androgen-independent state is intermittent androgen suppression (IAS) therapy, which ceases dosing intermittently. In this paper, we propose two methods to estimate the dynamics of prostate cancer, and investigate the IAS therapy from the viewpoint of optimality. The two methods that we propose for dynamics estimation are a variational Bayesian method for a piecewise affine (PWA) system and a Gaussian process regression method. We apply the proposed methods to real clinical data and compare their predictive performances. Then, using the estimated dynamics of prostate cancer, we observe how prostate cancer behaves for various dosing schedules. It can be seen that the conventional IAS therapy is a way of imposing high cost for dosing while keeping the prostate cancer in a safe state. We would like to dedicate this paper to the memory of Professor Luigi M. Ricciardi. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

Safety, adherence and acceptability of intermittent tenofovir/emtricitabine as HIV pre-exposure prophylaxis (PrEP among HIV-uninfected Ugandan volunteers living in HIV-serodiscordant relationships: a randomized, clinical trial.

Directory of Open Access Journals (Sweden)

Freddie M Kibengo

Full Text Available BACKGROUND: Efficacy of oral pre-exposure prophylaxis (PrEP in prevention of HIV acquisition has been evaluated using a daily regimen. However, adherence to long term daily medication is rarely perfect. Intermittent regimen may be a feasible alternative. Preclinical studies have demonstrated effectiveness of intermittent PrEP in SHIV prevention among animals. However, little is known about intermittent PrEP regimens. DESIGN: Seventy two HIV-uninfected volunteers in HIV serodiscordant couple relationships in Uganda were randomly assigned to receive daily oral Tenofovir/Emtricitabine (TDF/FTC-Truvada or placebo, or intermittent (Monday, Friday and within 2 hours after sex, not to exceed one dose per day oral TDF/FTC or placebo in a 2:1:2:1 ratio. Volunteers and study staff were blinded to drug assignment, but not to regimen assignment. METHODS: Volunteers were followed for 4 months after randomization, with monthly clinical and laboratory safety assessments and comprehensive HIV risk reduction services. Adherence was monitored using medication event monitoring system (MEMS and self-report. Sexual activity data were collected via daily short text message (SMS and self-report. HIV-specific immune responses were assessed by IFN-γ ELISPOT. RESULTS: Both daily and intermittent oral TDF/FTC regimens were well tolerated. Median MEMS adherence rates were 98% (IQR: 93-100 for daily PrEP regimen, 91% (IQR: 73-97 for fixed intermittent dosing and 45% (IQR: 20-63 for post-coital dosing. SMS response rate was 74%, but increased to 80% after excluding server outages; results may have been affected by the novelty of this measure. The majority of volunteers expressed willingness with no particular preference for either regimen. CONCLUSIONS: Both daily and intermittent oral PrEP dosing regimens were safe. Adherence was high for daily and fixed intermittent dosing; post-coital dosing was associated with poor adherence. Fixed intermittent PrEP regimens may be

Intermittent fasting and cardiovascular disease: current evidence and unresolved questions.

Science.gov (United States)

Tinsley, Grant M; Horne, Benjamin D

2018-01-01

Intermittent fasting has produced a variety of beneficial health effects in animal models, although high-quality research in humans has been limited. This special report examines current evidences for intermittent fasting in humans, discusses issues that require further examination, and recommends new research that can improve the knowledge base in this emerging research area. While potentially useful for health improvement, intermittent fasting requires further study prior to widespread implementation for health purposes. Randomized, longer-term studies are needed to determine whether using intermittent fasting as a lifestyle rather than a diet is feasible and beneficial for the health of some members of the human population.

A prospective, randomized, blinded-endpoint, controlled study - continuous epidural infusion versus programmed intermittent epidural bolus in labor analgesia

Directory of Open Access Journals (Sweden)

Joana Nunes

Full Text Available Abstract Background: There is evidence that administration of a programmed intermittent epidural bolus (PIEB compared to continuous epidural infusion (CEI leads to greater analgesia efficacy and maternal satisfaction with decreased anesthetic interventions. Methods: In this study, 166 women with viable pregnancies were included. After an epidural loading dose of 10 mL with Ropivacaine 0.16% plus Sufentanil 10 µg, parturient were randomly assigned to one of three regimens: A - Ropivacaine 0.15% plus Sufentanil 0.2 µg/mL solution as continuous epidural infusion (5 mL/h, beginning immediately after the initial bolus; B - Ropivacaine 0.1% plus Sufentanil 0.2 µg/mL as programmed intermittent epidural bolus and C - Same solution as group A as programmed intermittent epidural bolus. PIEB regimens were programmed as 10 mL/h starting 60 min after the initial bolus. Rescue boluses of 5 mL of the same solution were administered, with the infusion pump. We evaluated maternal satisfaction using a verbal numeric scale from 0 to 10. We also evaluated adverse, maternal and neonatal outcomes. Results: We analyzed 130 pregnants (A = 60; B = 33; C = 37. The median verbal numeric scale for maternal satisfaction was 8.8 in group A; 8.6 in group B and 8.6 in group C (p = 0.83. We found a higher caesarean delivery rate in group A (56.7%; p = 0.02. No differences in motor block, instrumental delivery rate and neonatal outcomes were observed. Conclusions: Maintenance of epidural analgesia with programmed intermittent epidural bolus is associated with a reduced incidence of caesarean delivery with equally high maternal satisfaction and no adverse outcomes.

Adequacy in dialysis: intermittent versus continuous therapies.

Science.gov (United States)

Misra, M; Nolph, K D

2000-01-01

A vital conceptual difference between intermittent and continuous dialysis therapies is the difference in the relationship between Kt/V urea and dietary protein intake. For a given level of protein intake the intermittent therapies require a higher Kt/V urea due to the reasons mentioned above. The recently released adequacy guidelines by DOQI for intermittent and continuous therapies are based on these assumptions. The link between adequacy targets and patient survival is well documented for an intermittent therapy like HD. For a continuous therapy like CAPD however, the evidence linking improved peritoneal clearance to better survival is not as direct. However, present consensus allows one to extrapolate results based on HD. The concept of earlier and healthier initiation of dialysis is gaining hold and incremental dialysis forms an integral aspect of the whole concept. Tools like urea kinetic modeling give us valuable insight in making mathematical projections about the timing as well as dosing of dialysis. Daily home hemodialysis is still an underutilized modality despite offering best survival figures. Hopefully, with increasing availability of better and simpler machines its use will increase. Still several questions remain unanswered. Despite availability of data in hemodialysis patients suggesting that an increased dialysis prescription leads to a better survival, optimal dialysis dose is yet to be defined. Concerns regarding methodology of such studies and conclusions thereof has been raised. Other issues relating to design of the studies, variation in dialysis delivery, use of uncontrolled historical standards and lack of patient randomization etc also need to be considered when designing such trials. Hopefully an ongoing prospective randomized trial, namely the HEMO study, looking at two precisely defined and carefully maintained dialysis prescriptions will provide some insight into adequacy of dialysis dose and survival. In diabetic patients, the

Improvement of walking distance by defibrotide in patients with intermittent claudication--results of a randomized, placebo-controlled study (the DICLIS study). Defibrotide Intermittent CLaudication Italian Study.

Science.gov (United States)

Violi, F; Marubini, E; Coccheri, S; Nenci, G G

2000-05-01

Defibrotide is an antithrombotic drug which enhances prostacyclin production and activates fibrinolytic system. The aim of this study was to investigate the improvement of walking distance in patients with intermittent claudication treated with defibrotide. DICLIS was a double blind, placebo-controlled study which included patients with walking distance autonomy at a standardized treadmill test or =100 meters. A total of 310 patients were randomly allocated to placebo (n = 101), defibrotide 800 mg/day (n = 104) or defibrotide 1200 mg/day (n = 105). During a one year follow-up, the Absolute Walking Distance (AWD) was measured six times (0, 30, 60, 90, 180, 360 days). Similar improvement in walking distance was found in the three groups until the 90th day; thereafter placebo group showed no further increase, while AWD continued to increase in the defibrotide groups. Between the 180th and 360th day visits, AWD was significantly higher (P defibrotide than in patients given placebo. No difference in efficacy was observed between the two dosages of defibrotide. No differences in side effects were observed among the three groups. The results of the present trial suggest that long-term administration of defibrotide improves walking distance in patients with intermittent claudication.

The stochastic dynamics of intermittent porescale particle motion

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Dentz, Marco; Morales, Veronica; Puyguiraud, Alexandre; Gouze, Philippe; Willmann, Matthias; Holzner, Markus

2017-04-01

Numerical and experimental data for porescale particle dynamics show intermittent patterns in Lagrangian velocities and accelerations, which manifest in long time intervals of low and short durations of high velocities [1, 2]. This phenomenon is due to the spatial persistence of particle velocities on characteristic heterogeneity length scales. In order to systematically quantify these behaviors and extract the stochastic dynamics of particle motion, we focus on the analysis of Lagrangian velocities sampled equidistantly along trajectories [3]. This method removes the intermittency observed under isochrone sampling. The space-Lagrangian velocity series can be quantified by a Markov process that is continuous in distance along streamline. It is fully parameterized in terms of the flux-weighted Eulerian velocity PDF and the characteristic pore-length. The resulting stochastic particle motion describes a continuous time random walk (CTRW). This approach allows for the process based interpretation of experimental and numerical porescale velocity, acceleration and displacement data. It provides a framework for the characterization and upscaling of particle transport and dispersion from the pore to the Darcy-scale based on the medium geometry and Eulerian flow attributes. [1] P. De Anna, T. Le Borgne, M. Dentz, A.M. Tartakovsky, D. Bolster, and P. Davy, "Flow intermittency, dispersion, and correlated continuous time random walks in porous media," Phys. Rev. Lett. 110, 184502 (2013). [2] M. Holzner, V. L. Morales, M. Willmann, and M. Dentz, "Intermittent Lagrangian velocities and accelerations in three- dimensional porous medium flow," Phys. Rev. E 92, 013015 (2015). [3] M. Dentz, P. K. Kang, A. Comolli, T. Le Borgne, and D. R. Lester, "Continuous time random walks for the evolution of Lagrangian velocities," Phys. Rev. Fluids (2016).

A prospective, randomized, blinded-endpoint, controlled study - continuous epidural infusion versus programmed intermittent epidural bolus in labor analgesia.

Science.gov (United States)

Nunes, Joana; Nunes, Sara; Veiga, Mariano; Cortez, Mara; Seifert, Isabel

2016-01-01

There is evidence that administration of a programmed intermittent epidural bolus (PIEB) compared to continuous epidural infusion (CEI) leads to greater analgesia efficacy and maternal satisfaction with decreased anesthetic interventions. In this study, 166 women with viable pregnancies were included. After an epidural loading dose of 10mL with Ropivacaine 0.16% plus Sufentanil 10μg, parturient were randomly assigned to one of three regimens: A - Ropivacaine 0.15% plus Sufentanil 0.2μg/mL solution as continuous epidural infusion (5mL/h, beginning immediately after the initial bolus); B - Ropivacaine 0.1% plus Sufentanil 0.2μg/mL as programmed intermittent epidural bolus and C - Same solution as group A as programmed intermittent epidural bolus. PIEB regimens were programmed as 10mL/h starting 60min after the initial bolus. Rescue boluses of 5mL of the same solution were administered, with the infusion pump. We evaluated maternal satisfaction using a verbal numeric scale from 0 to 10. We also evaluated adverse, maternal and neonatal outcomes. We analyzed 130 pregnants (A=60; B=33; C=37). The median verbal numeric scale for maternal satisfaction was 8.8 in group A; 8.6 in group B and 8.6 in group C (p=0.83). We found a higher caesarean delivery rate in group A (56.7%; p=0.02). No differences in motor block, instrumental delivery rate and neonatal outcomes were observed. Maintenance of epidural analgesia with programmed intermittent epidural bolus is associated with a reduced incidence of caesarean delivery with equally high maternal satisfaction and no adverse outcomes. Copyright © 2015 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. All rights reserved.

Analyzing the Efficiency of Introduction of the Intermittent Heating Mode

Science.gov (United States)

Anisimova, E.; Shcherbak, A.

2017-11-01

The efficiency of introduction of an optimal intermittent heating mode for a service center building in Chelyabinsk is estimated. The optimal intermittent heating mode ensures heat energy saving while maintaining the required microclimate parameters. The graphical dependencies of the amount of heat energy saving on the heat retention of the building and the outdoor air temperature are shown. The fundamental formulas which were the basis for calculating the periods of cooling, warming and expenditures of heat energy for the two heating modes are given. The literature on the issue is reviewed, the main points, advantages and disadvantages in the works of both Russian and foreign authors are revealed. The calculation was carried out in compliance with the modern state standards and regulatory documents. The capital costs of a system construction with an intermittent heating mode are determined.

Fuzziness and randomness in an optimization framework

International Nuclear Information System (INIS)

Luhandjula, M.K.

1994-03-01

This paper presents a semi-infinite approach for linear programming in the presence of fuzzy random variable coefficients. As a byproduct a way for dealing with optimization problems including both fuzzy and random data is obtained. Numerical examples are provided for the sake of illustration. (author). 13 refs

Intermittent Preventive Treatment for Malaria in Pregnancy: Optimization of Target Concentrations of Dihydroartemisinin-Piperaquine.

Science.gov (United States)

Savic, Rada M; Jagannathan, Prasanna; Kajubi, Richard; Huang, Liusheng; Zhang, Nan; Were, Moses; Kakuru, Abel; Muhindo, Mary K; Mwebaza, Norah; Wallender, Erika; Clark, Tamara D; Opira, Bishop; Kamya, Moses; Havlir, Diane V; Rosenthal, Philip J; Dorsey, Grant; Aweeka, Francesca T

2018-03-14

Dihydroartemsinin-piperaquine is highly efficacious as intermittent preventive therapy for malaria during pregnancy (IPTp). Determining associations between piperaquine exposure, malaria risk, and adverse birth outcomes informs optimal dosing strategies. HIV-uninfected pregnant women were enrolled in a placebo-controlled trial of IPTp at 12-20 weeks gestation and randomized to: sulfadoxine-pyrimethamine every 8 weeks (n=106), dihydroartemsinin-piperaquine every 8 weeks (n=94), or dihydroartemsinin-piperaquine every 4 weeks (n=100) during pregnancy. Pharmacokinetic sampling for piperaquine was performed every 4 weeks, and an intensive pharmacokinetic sub-study was performed in 30 women at 28 weeks gestation. Concentration-effect relationships were assessed between exposure to piperaquine; the prevalence of P. falciparum infection during pregnancy; outcomes at delivery including placental malaria, low birthweight, and preterm birth; and risks for toxicity. Simulations of new dosing scenarios were performed. Model-defined piperaquine target venous plasma concentrations of 13.9 ng/ml provided 99% protection from P. falciparum infection during pregnancy. Each 10 day increase in time>target piperaquine concentrations was associated with reduced odds of placental parasitemia (0∙67, P<0.0001), preterm birth (0.74, P<0.01), and low birthweight (0.74, P<0.05), though increases in piperaquine concentrations were associated with QTc prolongation (5 msec increase per 100 ng/ml). Modeling suggests that daily or weekly administration of lower dosages of piperaquine, compared to standard dosing, will maintain piperaquine trough levels above target concentrations with reduced piperaquine peak levels, potentially limiting toxicity. The protective efficacy of IPTp with dihydroartemsinin-piperaquine was strongly associated with higher drug exposure. Studies of the efficacy and safety of alternative dihydroartemsinin-piperaquine IPTp dosing strategies are warranted. NCT02163447.

Intermittent preventive treatment of malaria in pregnancy

DEFF Research Database (Denmark)

Mbonye, A.K.; Bygbjerg, Ib Christian; Magnussen, Pascal

2008-01-01

OBJECTIVE: To assess whether traditional birth attendants, drug-shop vendors, community reproductive-health workers, or adolescent peer mobilizers could administer intermittent preventive treatment (IPTp) for malaria with sulfadoxine-pyrimethamine to pregnant women. METHODS: A non-randomized comm......OBJECTIVE: To assess whether traditional birth attendants, drug-shop vendors, community reproductive-health workers, or adolescent peer mobilizers could administer intermittent preventive treatment (IPTp) for malaria with sulfadoxine-pyrimethamine to pregnant women. METHODS: A non......-randomized community trial was implemented in 21 community clusters (intervention) and four clusters where health units provided routine IPTp (control). The primary outcome measures were access and adherence to IPTp, number of malaria episodes, prevalence of anaemia, and birth weight. Numbers of live births, abortions......, still births, and maternal and child deaths were secondary endpoints. FINDINGS: 1404 (67.5%) of 2081 with the new delivery system received two doses of sulfadoxine-pyrimethamine versus 281 (39.9%) of 704 with health units (P malaria episodes decreased from 906 (49...

Energy intermittency

CERN Document Server

Sorensen, Bent

2014-01-01

The first book to consider intermittency as a key point of an energy system, Energy Intermittency describes different levels of variability for traditional and renewable energy sources, presenting detailed solutions for handling energy intermittency through trade, collaboration, demand management, and active energy storage. Addressing energy supply intermittency systematically, this practical text:Analyzes typical time-distributions and intervals between episodes of demand-supply mismatch and explores their dependence on system layouts and energy source characteristicsSimulates scenarios regar

The Felix-trial. Double-blind randomization of interspinous implant or bony decompression for treatment of spinal stenosis related intermittent neurogenic claudication

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Brand Ronald

2010-05-01

Full Text Available Abstract Background Decompressive laminotomy is the standard surgical procedure in the treatment of patients with canal stenosis related intermittent neurogenic claudication. New techniques, such as interspinous process implants, claim a shorter hospital stay, less post-operative pain and equal long-term functional outcome. A comparative (cost- effectiveness study has not been performed yet. This protocol describes the design of a randomized controlled trial (RCT on (cost- effectiveness of the use of interspinous process implants versus conventional decompression surgery in patients with lumbar spinal stenosis. Methods/Design Patients (age 40-85 presenting with intermittent neurogenic claudication due to lumbar spinal stenosis lasting more than 3 months refractory to conservative treatment, are included. Randomization into interspinous implant surgery versus bony decompression surgery will take place in the operating room after induction of anesthesia. The primary outcome measure is the functional assessment of the patient measured by the Zurich Claudication Questionnaire (ZCQ, at 8 weeks and 1 year after surgery. Other outcome parameters include perceived recovery, leg and back pain, incidence of re-operations, complications, quality of life, medical consumption, absenteeism and costs. The study is a randomized multi-institutional trial, in which two surgical techniques are compared in a parallel group design. Patients and research nurses are kept blinded of the allocated treatment during the follow-up period of 1 year. Discussion Currently decompressive laminotomy is the golden standard in the surgical treatment of lumbar spinal stenosis. Whether surgery with interspinous implants is a reasonable alternative can be determined by this trial. Trial register Dutch Trial register number: NTR1307

Intermittent cryogen spray cooling for optimal heat extraction during dermatologic laser treatment

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Majaron, Boris; Svaasand, Lars O.; Aguilar, Guillermo; Nelson, J. Stuart

2002-09-01

Fast heat extraction is critically important to obtain the maximal benefit of cryogen spray cooling (CSC) during laser therapy of shallow skin lesions, such as port wine stain birthmarks. However, a film of liquid cryogen can build up on the skin surface, impairing heat transfer due to the relatively low thermal conductivity and higher temperature of the film as compared to the impinging spray droplets. In an attempt to optimize the cryogen mass flux, while minimally affecting other spray characteristics, we apply a series of 10 ms spurts with variable duty cycles. Heat extraction dynamics during such intermittent cryogen sprays were measured using a custom-made metal-disc detector. The highest cooling rates were observed at moderate duty cycle levels. This confirms the presence, and offers a practical way to eliminate the adverse effect of liquid cryogen build-up on the sprayed surface. On the other hand, lower duty cycles allow a substantial reduction in the average rate of heat extraction, enabling less aggressive and more efficient CSC for treatment of deeper targets, such as hair follicles.

Small-world networks exhibit pronounced intermittent synchronization

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Choudhary, Anshul; Mitra, Chiranjit; Kohar, Vivek; Sinha, Sudeshna; Kurths, Jürgen

2017-11-01

We report the phenomenon of temporally intermittently synchronized and desynchronized dynamics in Watts-Strogatz networks of chaotic Rössler oscillators. We consider topologies for which the master stability function (MSF) predicts stable synchronized behaviour, as the rewiring probability (p) is tuned from 0 to 1. MSF essentially utilizes the largest non-zero Lyapunov exponent transversal to the synchronization manifold in making stability considerations, thereby ignoring the other Lyapunov exponents. However, for an N-node networked dynamical system, we observe that the difference in its Lyapunov spectra (corresponding to the N - 1 directions transversal to the synchronization manifold) is crucial and serves as an indicator of the presence of intermittently synchronized behaviour. In addition to the linear stability-based (MSF) analysis, we further provide global stability estimate in terms of the fraction of state-space volume shared by the intermittently synchronized state, as p is varied from 0 to 1. This fraction becomes appreciably large in the small-world regime, which is surprising, since this limit has been otherwise considered optimal for synchronized dynamics. Finally, we characterize the nature of the observed intermittency and its dominance in state-space as network rewiring probability (p) is varied.

Hybrid computer optimization of systems with random parameters

Science.gov (United States)

White, R. C., Jr.

1972-01-01

A hybrid computer Monte Carlo technique for the simulation and optimization of systems with random parameters is presented. The method is applied to the simultaneous optimization of the means and variances of two parameters in the radar-homing missile problem treated by McGhee and Levine.

Randomized trial of piperaquine with sulfadoxine-pyrimethamine or dihydroartemisinin for malaria intermittent preventive treatment in children.

Directory of Open Access Journals (Sweden)

Badara Cisse

Full Text Available BACKGROUND: The long terminal half life of piperaquine makes it suitable for intermittent preventive treatment for malaria but no studies of its use for prevention have been done in Africa. We did a cluster randomized trial to determine whether piperaquine in combination with either dihydroartemisin (DHA or sulfadoxine-pyrimethamine (SP is as effective, and better tolerated, than SP plus amodiaquine (AQ, when used for intermittent preventive treatment in children delivered by community health workers in a rural area of Senegal. METHODS: Treatments were delivered to children 3-59 months of age in their homes once per month during the transmission season by community health workers. 33 health workers, each covering about 60 children, were randomized to deliver either SP+AQ, DHA+PQ or SP+PQ. Primary endpoints were the incidence of attacks of clinical malaria, and the incidence of adverse events. RESULTS: 1893 children were enrolled. Coverage of monthly rounds and compliance with daily doses was similar in all groups; 90% of children received at least 2 monthly doses. Piperaquine combinations were better tolerated than SP+AQ with a significantly lower risk of common, mild adverse events. 103 episodes of clinical malaria were recorded during the course of the trial. 68 children had malaria with parasitaemia >3000/microL, 29/671 (4.3% in the SP+AQ group, compared with 22/604 (3.6% in the DHA+PQ group (risk difference 0.47%, 95%CI -2.3%,+3.3%, and 17/618 (2.8% in the SP+PQ group (risk difference 1.2%, 95%CI -1.3%,+3.6%. Prevalences of parasitaemia and the proportion of children carrying Pfdhfr and Pfdhps mutations associated with resistance to SP were very low in all groups at the end of the transmission season. CONCLUSIONS: Seasonal IPT with SP+PQ in children is highly effective and well tolerated; the combination of two long-acting drugs is likely to impede the emergence of resistant parasites. TRIAL REGISTRATION: ClinicalTrials.gov NCT00529620.

Random Matrix Approach for Primal-Dual Portfolio Optimization Problems

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Tada, Daichi; Yamamoto, Hisashi; Shinzato, Takashi

2017-12-01

In this paper, we revisit the portfolio optimization problems of the minimization/maximization of investment risk under constraints of budget and investment concentration (primal problem) and the maximization/minimization of investment concentration under constraints of budget and investment risk (dual problem) for the case that the variances of the return rates of the assets are identical. We analyze both optimization problems by the Lagrange multiplier method and the random matrix approach. Thereafter, we compare the results obtained from our proposed approach with the results obtained in previous work. Moreover, we use numerical experiments to validate the results obtained from the replica approach and the random matrix approach as methods for analyzing both the primal and dual portfolio optimization problems.

Age replacement policy based on imperfect repair with random probability

International Nuclear Information System (INIS)

Lim, J.H.; Qu, Jian; Zuo, Ming J.

2016-01-01

In most of literatures of age replacement policy, failures before planned replacement age can be either minimally repaired or perfectly repaired based on the types of failures, cost for repairs and so on. In this paper, we propose age replacement policy based on imperfect repair with random probability. The proposed policy incorporates the case that such intermittent failure can be either minimally repaired or perfectly repaired with random probabilities. The mathematical formulas of the expected cost rate per unit time are derived for both the infinite-horizon case and the one-replacement-cycle case. For each case, we show that the optimal replacement age exists and is finite. - Highlights: • We propose a new age replacement policy with random probability of perfect repair. • We develop the expected cost per unit time. • We discuss the optimal age for replacement minimizing the expected cost rate.

Complex economic dynamics: Chaotic saddle, crisis and intermittency

International Nuclear Information System (INIS)

Chian, Abraham C.-L.; Rempel, Erico L.; Rogers, Colin

2006-01-01

Complex economic dynamics is studied by a forced oscillator model of business cycles. The technique of numerical modeling is applied to characterize the fundamental properties of complex economic systems which exhibit multiscale and multistability behaviors, as well as coexistence of order and chaos. In particular, we focus on the dynamics and structure of unstable periodic orbits and chaotic saddles within a periodic window of the bifurcation diagram, at the onset of a saddle-node bifurcation and of an attractor merging crisis, and in the chaotic regions associated with type-I intermittency and crisis-induced intermittency, in non-linear economic cycles. Inside a periodic window, chaotic saddles are responsible for the transient motion preceding convergence to a periodic or a chaotic attractor. The links between chaotic saddles, crisis and intermittency in complex economic dynamics are discussed. We show that a chaotic attractor is composed of chaotic saddles and unstable periodic orbits located in the gap regions of chaotic saddles. Non-linear modeling of economic chaotic saddle, crisis and intermittency can improve our understanding of the dynamics of financial intermittency observed in stock market and foreign exchange market. Characterization of the complex dynamics of economic systems is a powerful tool for pattern recognition and forecasting of business and financial cycles, as well as for optimization of management strategy and decision technology

Intermittent hypoxic episodes in preterm infants: do they matter?

Science.gov (United States)

Martin, Richard J; Wang, Katherine; Köroğlu, Ozge; Di Fiore, Juliann; Kc, Prabha

2011-01-01

Intermittent hypoxic episodes are typically a consequence of immature respiratory control and remain a troublesome challenge for the neonatologist. Furthermore, their frequency and magnitude are underestimated by clinically employed pulse oximeter settings. In extremely low birth weight infants the incidence of intermittent hypoxia progressively increases over the first 4 weeks of postnatal life, with a subsequent plateau followed by a slow decline beginning at weeks 6-8. Such episodic hypoxia/reoxygenation has the potential to sustain a proinflammatory cascade with resultant multisystem morbidity. This morbidity includes retinopathy of prematurity and impaired growth, as well as possible longer-term cardiorespiratory instability and poor neurodevelopmental outcome. Therapeutic approaches for intermittent hypoxic episodes comprise determination of optimal baseline saturation and careful titration of supplemental inspired oxygen, as well as xanthine therapy to prevent apnea of prematurity. In conclusion, characterization of the pathophysiologic basis for such intermittent hypoxic episodes and their consequences during early life is necessary to provide an evidence-based approach to their management. Copyright © 2011 S. Karger AG, Basel.

Using complete measurement statistics for optimal device-independent randomness evaluation

International Nuclear Information System (INIS)

Nieto-Silleras, O; Pironio, S; Silman, J

2014-01-01

The majority of recent works investigating the link between non-locality and randomness, e.g. in the context of device-independent cryptography, do so with respect to some specific Bell inequality, usually the CHSH inequality. However, the joint probabilities characterizing the measurement outcomes of a Bell test are richer than just the degree of violation of a single Bell inequality. In this work we show how to take this extra information into account in a systematic manner in order to optimally evaluate the randomness that can be certified from non-local correlations. We further show that taking into account the complete set of outcome probabilities is equivalent to optimizing over all possible Bell inequalities, thereby allowing us to determine the optimal Bell inequality for certifying the maximal amount of randomness from a given set of non-local correlations. (paper)

Cover times of random searches

Science.gov (United States)

Chupeau, Marie; Bénichou, Olivier; Voituriez, Raphaël

2015-10-01

How long must one undertake a random search to visit all sites of a given domain? This time, known as the cover time, is a key observable to quantify the efficiency of exhaustive searches, which require a complete exploration of an area and not only the discovery of a single target. Examples range from immune-system cells chasing pathogens to animals harvesting resources, from robotic exploration for cleaning or demining to the task of improving search algorithms. Despite its broad relevance, the cover time has remained elusive and so far explicit results have been scarce and mostly limited to regular random walks. Here we determine the full distribution of the cover time for a broad range of random search processes, including Lévy strategies, intermittent strategies, persistent random walks and random walks on complex networks, and reveal its universal features. We show that for all these examples the mean cover time can be minimized, and that the corresponding optimal strategies also minimize the mean search time for a single target, unambiguously pointing towards their robustness.

Intermittent versus continuous exercise training in chronic heart failure: a meta-analysis.

Science.gov (United States)

Smart, Neil A; Dieberg, Gudrun; Giallauria, Francesco

2013-06-20

We conducted a meta-analysis of randomized, controlled trials of combined strength and intermittent aerobic training, intermittent aerobic training only and continuous exercise training in heart failure patients. A systematic search was conducted of Medline (Ovid) (1950-September 2011), Embase.com (1974-September 2011), Cochrane Central Register of Controlled Trials and CINAHL (1981-September 19 2011). The search strategy included a mix of MeSH and free text terms for the key concepts heart failure, exercise training, interval training and intermittent exercise training. The included studies contained an aggregate of 446 patients, 212 completed intermittent exercise training, 66 only continuous exercise training, 59 completed combined intermittent and strength training and 109 sedentary controls. Weighted mean difference (MD) in Peak VO2 was 1.04mlkg(-1)min(-1) and (95% C.I.) was 0.42-1.66 (p=0.0009) in intermittent versus continuous exercise training respectively. Weighted mean difference in Peak VO2 was -1.10mlkg(-1)min(-1) (95% C.I.) was -1.83-0.37 p=0.003 for intermittent only versus intermittent and strength (combined) training respectively. In studies reporting VE/VCO2 for intermittent versus control groups, MD was -1.50 [(95% C.I. -2.64, -0.37), p=0.01] and for intermittent versus continuous exercise training MD was -1.35 [(95% C.I. -2.15, -0.55), p=0.001]. Change in peak VO2 was positively correlated with weekly exercise energy expenditure for intermittent exercise groups (r=0.48, p=0.05). Combined strength and intermittent exercise appears superior for peak VO2 changes when compared to intermittent exercise of similar exercise energy expenditure. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Effect of intermittent aerobic exercise on sleep quality and sleep disturbances in patients with rheumatoid arthritis

DEFF Research Database (Denmark)

Løppenthin, Katrine; Esbensen, Bente Appel; Jennum, Poul

2014-01-01

of an intermittent aerobic exercise intervention on sleep, assessed both objectively and subjectively in patients with rheumatoid arthritis. METHODS/DESIGN: A randomized controlled trial including 44 patients with rheumatoid arthritis randomly assigned to an exercise training intervention or to a control group....... The intervention consists of 18 session intermittent aerobic exercise training on a bicycle ergometer three times a week. Patients are evaluated according to objective changes in sleep as measured by polysomnography (primary outcome). Secondary outcomes include changes in subjective sleep quality and sleep...... disturbances, fatigue, pain, depressive symptoms, physical function, health-related quality of life and cardiorespiratory fitness. DISCUSSION: This trial will provide evidence of the effect of intermittent aerobic exercise on the improvement of sleep in patients with rheumatoid arthritis, which is considered...

A pilot randomized clinical trial of intermittent occlusion therapy liquid crystal glasses versus traditional patching for treatment of moderate unilateral amblyopia.

Science.gov (United States)

Wang, Jingyun; Neely, Daniel E; Galli, Jay; Schliesser, Joshua; Graves, April; Damarjian, Tina G; Kovarik, Jessica; Bowsher, James; Smith, Heather A; Donaldson, Dana; Haider, Kathryn M; Roberts, Gavin J; Sprunger, Derek T; Plager, David A

2016-08-01

To compare the effectiveness of intermittent occlusion therapy (IO therapy) using liquid crystal glasses and continuous occlusion therapy using traditional adhesive patches for treating amblyopia. Children 3-8 years of age with previously untreated, moderate, unilateral amblyopia (visual acuity of 20/40 to 20/100 in the amblyopic eye) were enrolled in this randomized controlled trial. Amblyopia was associated with strabismus, anisometropia, or both. All subjects had worn any optimal refractive correction for at least 12 weeks without improvement. Subjects were randomized into two treatment groups: a 4-hour IO therapy group with liquid crystal glasses (Amblyz), set at 30-second opaque/transparent intervals (occluded 50% of wear time), and a 2-hour continuous patching group (occluded 100% of wear time). For each patient, visual acuity was measured using ATS-HOTV before and after 12 weeks of treatment. Data from 34 patients were available for analysis. Amblyopic eye visual acuity improvement from baseline was 0.15 ± 0.12 logMAR (95% CI, 0.09-0.15) in the IO therapy group (n = 19) and 0.15 ± 0.11 logMAR (95% CI, 0.1-0.15) in the patching group (n = 15). In both groups improvement was significant, but the difference between groups was not (P = 0.73). No adverse effects were reported. In this pilot study, IO therapy with liquid crystal glasses is not inferior to adhesive patching and is a promising alternative treatment for children 3-8 years of age with moderate amblyopia. Copyright © 2016 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

Intermittent search strategies

Science.gov (United States)

Bénichou, O.; Loverdo, C.; Moreau, M.; Voituriez, R.

2011-01-01

This review examines intermittent target search strategies, which combine phases of slow motion, allowing the searcher to detect the target, and phases of fast motion during which targets cannot be detected. It is first shown that intermittent search strategies are actually widely observed at various scales. At the macroscopic scale, this is, for example, the case of animals looking for food; at the microscopic scale, intermittent transport patterns are involved in a reaction pathway of DNA-binding proteins as well as in intracellular transport. Second, generic stochastic models are introduced, which show that intermittent strategies are efficient strategies that enable the minimization of search time. This suggests that the intrinsic efficiency of intermittent search strategies could justify their frequent observation in nature. Last, beyond these modeling aspects, it is proposed that intermittent strategies could also be used in a broader context to design and accelerate search processes.

A modelling breakthrough for market design analysis to test massive intermittent generation integration in markets results of selected OPTIMATE studies

DEFF Research Database (Denmark)

Beaude, Francois; Atayi, A.; Bourmaud, J.-Y.

2013-01-01

The OPTIMATE1 platform focuses on electricity system and market designs modelling in order to assess current and innovative designs in Europe. The current paper describes the results of the first validation studies' conducted with the tool. These studies deal with day-ahead market rules, load...... flexibility, cross-border management and intermittent renewable support schemes with a view to better integrating large amounts of renewable energy in Europe. Market and system designs were assessed based on economic efficiency, security of supply2 and environmental impact3 indicators. These results give...

[Effect of intermittent hypoxia of sleep apnea on embryonic rat cortical neurons in vitro].

Science.gov (United States)

Zhang, Chanjuan; Li, Yanzhong; Wang, Yan

2015-05-01

To investigate the effects of different pattens of intermittent hypoxia on the activity and apoptosis of primary cultured rat embryonic cortical neurons, and to evaluate the role of intermittent hypoxia in the mechanism of obstructive sleep syndrom induced cognitive function loss. The embryonic cerebral cortical neurons were cultured in vitro and were identified by immunofluorescence. Cultured neurons were randomly divided into intermittent hypoxia group, intermittent normal oxygen group, persistent hypoxia group and the control group, and intermittent hypoxia group was divided into five subgroups according to different frequency and time-bound. Neurons were exposed in different modes of hypoxia. MTT colorimetry was used to detect the viability of the neurons, and DAPI colorated measurement was used to calculate the percentages of neuron apoptosis. There were significantly different effects between all subgroups of intermittent hypoxia and the continued hypoxia group on neuronal activity and apoptosis (P Intermittent hypoxia groups with different frequency and time had no difference in neuronal activity and apoptosis (P > 0.05). The effect of intermittent hypoxia was more serious than that of continued hypoxia on neuronal activity and apoptosis; The impact of intermittent hypoxia on neuronal activity and apoptosis may be an important factor in obstructive sleep apnea related cognitive impairment.

Midportion achilles tendon microcirculation after intermittent combined cryotherapy and compression compared with cryotherapy alone: a randomized trial.

Science.gov (United States)

Knobloch, Karsten; Grasemann, Ruth; Spies, Marcus; Vogt, Peter M

2008-11-01

The effect of combined cryotherapy/compression versus cryotherapy alone on the Achilles tendon is undetermined. Standardized combined cryotherapy/compression changes in midportion Achilles tendon microcirculation are superior to those with cryotherapy during intermittent application. Controlled laboratory study. Sixty volunteers were randomized for either combined cryotherapy/compression (Cryo/Cuff, DJO Inc, Vista, California: n = 30; 32 +/- 11 years) or cryotherapy alone (KoldBlue, TLP Industries, Kent, United Kingdom: n = 30; 33 +/- 12 years) with intermittent 3 x 10-minute application. Midportion Achilles tendon microcirculation was determined (O2C, LEA Medizintechnik, Giessen, Germany). Both Cryo/Cuff and KoldBlue significantly reduced superficial and deep capillary tendon blood flow within the first minute of application (43 +/- 46 arbitrary units [AU] vs 10 +/- 19 AU and 42 +/- 46 AU vs 12 +/- 10 AU; P = .0001) without a significant difference throughout all 3 applications. However, during recovery, superficial and deep capillary blood flow was reestablished significantly faster using Cryo/Cuff (P = .023). Tendon oxygen saturation was reduced in both groups significantly (3 minutes Cryo/Cuff: 36% +/- 20% vs 16% +/- 15%; KoldBlue: 42% +/- 19% vs 28% +/- 20%; P cryotherapy and compression with significantly increased tendon oxygen saturation during recovery in contrast to cryotherapy alone. Both regimens lead to a significant amelioration of tendinous venous outflow. Combined cryotherapy and compression is superior to cryotherapy alone regarding the Achilles tendon microcirculation. Further studies in tendinopathy and tendon rehabilitation are warranted to elucidate its value regarding functional issues.

Intermittency in nuclear multifragmentation

International Nuclear Information System (INIS)

Ploszajczak, M.; Tucholski, A.

1990-07-01

Fluctuations of the fragment size distribution in a percolation model and in nuclear multifragmentation following the breakup of high energy nuclei in the nuclear emulsion are studied using the method of scaled factorial moments. An intermittent patern of fluctuations is found in the data as well as in the percolation lattice calculation. This is a consequence of both a self-similarity in the fragment size distribution and a random character for the scaling law. These fluctuations are in general well-described by percolation model. The multifractal dimensions are calculated and their relevance to the study of possible critical behaviour is pointed out. (orig.)

Optimal Quantum Spatial Search on Random Temporal Networks

Science.gov (United States)

Chakraborty, Shantanav; Novo, Leonardo; Di Giorgio, Serena; Omar, Yasser

2017-12-01

To investigate the performance of quantum information tasks on networks whose topology changes in time, we study the spatial search algorithm by continuous time quantum walk to find a marked node on a random temporal network. We consider a network of n nodes constituted by a time-ordered sequence of Erdös-Rényi random graphs G (n ,p ), where p is the probability that any two given nodes are connected: After every time interval τ , a new graph G (n ,p ) replaces the previous one. We prove analytically that, for any given p , there is always a range of values of τ for which the running time of the algorithm is optimal, i.e., O (√{n }), even when search on the individual static graphs constituting the temporal network is suboptimal. On the other hand, there are regimes of τ where the algorithm is suboptimal even when each of the underlying static graphs are sufficiently connected to perform optimal search on them. From this first study of quantum spatial search on a time-dependent network, it emerges that the nontrivial interplay between temporality and connectivity is key to the algorithmic performance. Moreover, our work can be extended to establish high-fidelity qubit transfer between any two nodes of the network. Overall, our findings show that one can exploit temporality to achieve optimal quantum information tasks on dynamical random networks.

Optimal Quantum Spatial Search on Random Temporal Networks.

Science.gov (United States)

Chakraborty, Shantanav; Novo, Leonardo; Di Giorgio, Serena; Omar, Yasser

2017-12-01

To investigate the performance of quantum information tasks on networks whose topology changes in time, we study the spatial search algorithm by continuous time quantum walk to find a marked node on a random temporal network. We consider a network of n nodes constituted by a time-ordered sequence of Erdös-Rényi random graphs G(n,p), where p is the probability that any two given nodes are connected: After every time interval τ, a new graph G(n,p) replaces the previous one. We prove analytically that, for any given p, there is always a range of values of τ for which the running time of the algorithm is optimal, i.e., O(sqrt[n]), even when search on the individual static graphs constituting the temporal network is suboptimal. On the other hand, there are regimes of τ where the algorithm is suboptimal even when each of the underlying static graphs are sufficiently connected to perform optimal search on them. From this first study of quantum spatial search on a time-dependent network, it emerges that the nontrivial interplay between temporality and connectivity is key to the algorithmic performance. Moreover, our work can be extended to establish high-fidelity qubit transfer between any two nodes of the network. Overall, our findings show that one can exploit temporality to achieve optimal quantum information tasks on dynamical random networks.

Optimal redundant systems for works with random processing time

International Nuclear Information System (INIS)

Chen, M.; Nakagawa, T.

2013-01-01

This paper studies the optimal redundant policies for a manufacturing system processing jobs with random working times. The redundant units of the parallel systems and standby systems are subject to stochastic failures during the continuous production process. First, a job consisting of only one work is considered for both redundant systems and the expected cost functions are obtained. Next, each redundant system with a random number of units is assumed for a single work. The expected cost functions and the optimal expected numbers of units are derived for redundant systems. Subsequently, the production processes of N tandem works are introduced for parallel and standby systems, and the expected cost functions are also summarized. Finally, the number of works is estimated by a Poisson distribution for the parallel and standby systems. Numerical examples are given to demonstrate the optimization problems of redundant systems

A Particle Swarm Optimization Algorithm with Variable Random Functions and Mutation

Institute of Scientific and Technical Information of China (English)

ZHOU Xiao-Jun; YANG Chun-Hua; GUI Wei-Hua; DONG Tian-Xue

2014-01-01

The convergence analysis of the standard particle swarm optimization (PSO) has shown that the changing of random functions, personal best and group best has the potential to improve the performance of the PSO. In this paper, a novel strategy with variable random functions and polynomial mutation is introduced into the PSO, which is called particle swarm optimization algorithm with variable random functions and mutation (PSO-RM). Random functions are adjusted with the density of the population so as to manipulate the weight of cognition part and social part. Mutation is executed on both personal best particle and group best particle to explore new areas. Experiment results have demonstrated the effectiveness of the strategy.

Theory of Randomized Search Heuristics in Combinatorial Optimization

DEFF Research Database (Denmark)

The rigorous mathematical analysis of randomized search heuristics(RSHs) with respect to their expected runtime is a growing research area where many results have been obtained in recent years. This class of heuristics includes well-known approaches such as Randomized Local Search (RLS), the Metr......The rigorous mathematical analysis of randomized search heuristics(RSHs) with respect to their expected runtime is a growing research area where many results have been obtained in recent years. This class of heuristics includes well-known approaches such as Randomized Local Search (RLS...... analysis of randomized algorithms to RSHs. Mostly, the expected runtime of RSHs on selected problems is analzyed. Thereby, we understand why and when RSHs are efficient optimizers and, conversely, when they cannot be efficient. The tutorial will give an overview on the analysis of RSHs for solving...

Sprint vs. intermittent training in young female basketball players.

Science.gov (United States)

Attene, G; Pizzolato, F; Calcagno, G; Ibba, G; Pinna, M; Salernitano, G; Padulo, J

2014-04-01

This study aimed at comparing the effects of intermittent and repeated sprint ability training on physiological variables. Sixteen young female basketball players were randomly allocated to intermittent training (IT=8) or repeated sprint ability training (RST=8) groups. The following outcomes were measured at baseline and after 6 weeks of training: Yo-Yo intermittent recovery (Yo-Yo) and repeated sprint ability (RSA) tests. For all the variables investigated the effect of training type showed a different trend respect at current knowledge. In the RSA, best time (BT) was a significant main effect of training time (pre- vs. post-) (Ptraining type/time (P=0.03). The RST showed a decrease in BT of 3.1% (P=0.005) while the IT showed a decrease of 6.2% (Ptraining methods used in this study can be an effective training strategy for inducing anaerobic and basketball-specific training schedules. Besides, even when IT training is not done at very high speed, it can increase the maximum speed of the RSA.

On intermittent flow characteristics of gas–liquid two-phase flow

Energy Technology Data Exchange (ETDEWEB)

Thaker, Jignesh; Banerjee, Jyotirmay, E-mail: jbaner@gmail.com

2016-12-15

Highlights: • Unified correlations for intermittent flow characteristics are developed. • Influence of inflow conditions on intermittent flow characteristics is analysed. • Developed correlations can be used for effective design of piping components. - Abstract: Flow visualisation experiments are reported for intermittent regime of gas–liquid two-phase flow. Intermittent flow characteristics, which include plug/slug frequency, liquid plug/slug velocity, liquid plug/slug length, and plug/slug bubble length are determined by image processing of flow patterns captured at a rate of 1600 frames per second (FPS). Flow characteristics are established as a function of inlet superficial velocity of both the phases (in terms of Re{sub SL} and Re{sub SG}). The experimental results are first validated with the existing correlations for slug flow available in literature. It is observed that the correlations proposed in literature for slug flow do not accurately predict the flow characteristics in the plug flow regime. The differences are clearly highlighted in this paper. Based on the measured database for both plug and slug flow regime, modified correlations for the intermittent flow regime are proposed. The correlations reported in the present paper, which also include plug flow characteristics will aid immensely to the effective design and optimization of operating conditions for safer operation of two-phase flow piping systems.

A randomized trial comparing part-time patching with observation for children 3 to 10 years of age with intermittent exotropia.

Science.gov (United States)

Cotter, Susan A; Mohney, Brian G; Chandler, Danielle L; Holmes, Jonathan M; Repka, Michael X; Melia, Michele; Wallace, David K; Beck, Roy W; Birch, Eileen E; Kraker, Raymond T; Tamkins, Susanna M; Miller, Aaron M; Sala, Nicholas A; Glaser, Stephen R

2014-12-01

To determine the effectiveness of prescribed part-time patching for treatment of intermittent exotropia (IXT) in children. Multicenter, randomized clinical trial. Three hundred fifty-eight children 3 to part-time patching group (difference, 5.4%; lower limit of 1-sided exact 95% confidence interval, 2.0%; P = 0.004, 1-sided hypothesis test). Deterioration of previously untreated childhood IXT over a 6-month period is uncommon with or without patching treatment. Although there is a slightly lower deterioration rate with patching, both management approaches are reasonable for treating children 3 to 10 years of age with IXT. Copyright © 2014 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Optimal strategy analysis based on robust predictive control for inventory system with random demand

Science.gov (United States)

Saputra, Aditya; Widowati, Sutrisno

2017-12-01

In this paper, the optimal strategy for a single product single supplier inventory system with random demand is analyzed by using robust predictive control with additive random parameter. We formulate the dynamical system of this system as a linear state space with additive random parameter. To determine and analyze the optimal strategy for the given inventory system, we use robust predictive control approach which gives the optimal strategy i.e. the optimal product volume that should be purchased from the supplier for each time period so that the expected cost is minimal. A numerical simulation is performed with some generated random inventory data. We simulate in MATLAB software where the inventory level must be controlled as close as possible to a set point decided by us. From the results, robust predictive control model provides the optimal strategy i.e. the optimal product volume that should be purchased and the inventory level was followed the given set point.

Effects of intermittent hypoxia on running economy.

Science.gov (United States)

Burtscher, M; Gatterer, H; Faulhaber, M; Gerstgrasser, W; Schenk, K

2010-09-01

We investigated the effects of two 5-wk periods of intermittent hypoxia on running economy (RE). 11 male and female middle-distance runners were randomly assigned to the intermittent hypoxia group (IHG) or to the control group (CG). All athletes trained for a 13-wk period starting at pre-season until the competition season. The IHG spent additionally 2 h at rest on 3 days/wk for the first and the last 5 weeks in normobaric hypoxia (15-11% FiO2). RE, haematological parameters and body composition were determined at low altitude (600 m) at baseline, after the 5 (th), the 8 (th) and the 13 (th) week of training. RE, determined by the relative oxygen consumption during submaximal running, (-2.3+/-1.2 vs. -0.3+/-0.7 ml/min/kg, Ptraining phase. Georg Thieme Verlag KG Stuttgart . New York.

Optimizing Event Selection with the Random Grid Search

Energy Technology Data Exchange (ETDEWEB)

Bhat, Pushpalatha C. [Fermilab; Prosper, Harrison B. [Florida State U.; Sekmen, Sezen [Kyungpook Natl. U.; Stewart, Chip [Broad Inst., Cambridge

2017-06-29

The random grid search (RGS) is a simple, but efficient, stochastic algorithm to find optimal cuts that was developed in the context of the search for the top quark at Fermilab in the mid-1990s. The algorithm, and associated code, have been enhanced recently with the introduction of two new cut types, one of which has been successfully used in searches for supersymmetry at the Large Hadron Collider. The RGS optimization algorithm is described along with the recent developments, which are illustrated with two examples from particle physics. One explores the optimization of the selection of vector boson fusion events in the four-lepton decay mode of the Higgs boson and the other optimizes SUSY searches using boosted objects and the razor variables.

Comparison of Urinary Tract Infection Rates Associated with Transurethral Catheterization, Suprapubic Tube and Clean Intermittent Catheterization in the Postoperative Setting: A Network Meta-Analysis.

Science.gov (United States)

Han, Christopher S; Kim, Sinae; Radadia, Kushan D; Zhao, Philip T; Elsamra, Sammy E; Olweny, Ephrem O; Weiss, Robert E

2017-12-01

We performed a network meta-analysis of available randomized, controlled trials to elucidate the risks of urinary tract infection associated with transurethral catheterization, suprapubic tubes and intermittent catheterization in the postoperative setting. PubMed®, EMBASE® and Google Scholar™ searches were performed for eligible randomized, controlled trials from January 1980 to July 2015 that included patients who underwent transurethral catheterization, suprapubic tube placement or intermittent catheterization at the time of surgery and catheterization lasting up to postoperative day 30. The primary outcome of comparison was the urinary tract infection rate via a network meta-analysis with random effects model using the netmeta package in R 3.2 (www.r-project.org/). Included in analysis were 14 randomized, controlled trials in a total of 1,391 patients. Intermittent catheterization and suprapubic tubes showed no evidence of decreased urinary tract infection rates compared to transurethral catheterization. Suprapubic tubes and intermittent catheterization had comparable urinary tract infection rates (OR 0.903, 95% CI 0.479-2.555). On subgroup analysis of 10 randomized, controlled trials with available mean catheterization duration data in a total of 928 patients intermittent catheterization and suprapubic tube were associated with significantly decreased risk of urinary tract infection compared to transurethral catheterization when catheterization duration was greater than 5 days (OR 0.173, 95% CI 0.073-0.412 and OR 0.142, 95% CI 0.073-0.276, respectively). Transurethral catheterization is not associated with an increased urinary tract infection risk compared to suprapubic tubes and intermittent catheterization if catheterization duration is 5 days or less. However, a suprapubic tube or intermittent catheterization is associated with a lower rate of urinary tract infection if longer term catheterization is expected in the postoperative period. Copyright �

Optimization of refueling-shuffling scheme in PWR core by random search strategy

International Nuclear Information System (INIS)

Wu Yuan

1991-11-01

A random method for simulating optimization of refueling management in a pressurized water reactor (PWR) core is described. The main purpose of the optimization was to select the 'best' refueling arrangement scheme which would produce maximum economic benefits under certain imposed conditions. To fulfill this goal, an effective optimization strategy, two-stage random search method was developed. First, the search was made in a manner similar to the stratified sampling technique. A local optimum can be reached by comparison of the successive results. Then the other random experiences would be carried on between different strata to try to find the global optimum. In general, it can be used as a practical tool for conventional fuel management scheme. However, it can also be used in studies on optimization of Low-Leakage fuel management. Some calculations were done for a typical PWR core on a CYBER-180/830 computer. The results show that the method proposed can obtain satisfactory approach at reasonable low computational cost

Effect of Linguizhugan decoction on hyperlipidemia rats with intermittent fasting.

Science.gov (United States)

Yang, Yubin; Qin, Jian; Ke, Bin; Zhang, Junjie; Shi, Lanying; Li, Qiong

2013-04-01

To explore the effect of Linguizhugan decoction on hyperlipidemia rats with caloric restriction. The hyperlipidemia model of rat was induced by high fat diet for 8 weeks. After the model was established, 26 rats were randomly divided into 4 groups: the control group (n = 6), the model group (n = 6), the intermittent fasting (IF) group (n = 8), and the IF and herbal medicine (IFH) group (n = 6). IF group was applied intermittent fasting every other day. The IFH group was given Linguizhugan decoction every day and intermittent fasting every other day. Blood samples were taken at the end of 16 weeks, and serum ghrelin and lipid was tested. Serum ghrelin in the IF group significantly increased (P < 0.01). Serum ghrelin in IFH group was lower than the IF group (P < 0.05), but higher than the model group (P < 0.01). Linguizhugan decoction may play a part in regulation of energy and appetite in hyperlipidemia rats with IF.

Intermittent degradation and schizotypy

Directory of Open Access Journals (Sweden)

Matthew W. Roché

2015-06-01

Full Text Available Intermittent degradation refers to transient detrimental disruptions in task performance. This phenomenon has been repeatedly observed in the performance data of patients with schizophrenia. Whether intermittent degradation is a feature of the liability for schizophrenia (i.e., schizotypy is an open question. Further, the specificity of intermittent degradation to schizotypy has yet to be investigated. To address these questions, 92 undergraduate participants completed a battery of self-report questionnaires assessing schizotypy and psychological state variables (e.g., anxiety, depression, and their reaction times were recorded as they did so. Intermittent degradation was defined as the number of times a subject’s reaction time for questionnaire items met or exceeded three standard deviations from his or her mean reaction time after controlling for each item’s information processing load. Intermittent degradation scores were correlated with questionnaire scores. Our results indicate that intermittent degradation is associated with total scores on measures of positive and disorganized schizotypy, but unrelated to total scores on measures of negative schizotypy and psychological state variables. Intermittent degradation is interpreted as potentially derivative of schizotypy and a candidate endophenotypic marker worthy of continued research.

A novel inclusion of intermittent generation resources in long term energy auctions

International Nuclear Information System (INIS)

Marambio, Rodrigo; Rudnick, Hugh

2017-01-01

Long term energy auctions are positioning as a valuable tool in order to attract new investments into power systems, especially in Latin American countries where emergent economies characteristics and their correspondent risks are usually present. Even though the focus of these auctions is the long term, there are short term issues involved which actual auction designs fail to include, resulting in an energy allocation that is not necessarily optimal for the system, a condition which becomes more evident in the presence of intermittent renewable technologies. A novel mechanism is formulated to obtain the optimal allocation in long term energy auctions, considering short term generation profiles from both intermittent and conventional base load technologies, and also their risk aversions. The proposed mechanism is developed and simulations are made for some scenarios in the Chilean power market, with different levels of renewable penetration. Significant cost savings are achieved for the final consumers in relation to energy purchases, in comparison with a mechanism that follows the demand profile. As more renewable intermittent capacity enters the power system it is evident the need for changes in the energy auctions allocation mechanisms, including elements to exploit the synergies among participants in the short term. - Highlights: • Risk management consideration in technology neutral auctions allocation. • Allocation mechanism in technology neutral auctions with intermittent technologies. • Renewable and conventional technologies energy auction offer curves. • Increase bid prices in auctions as a consequence of solar technology support.

Sustained versus intermittent lung inflation for resuscitation of preterm infants: a randomized controlled trial.

Science.gov (United States)

El-Chimi, Mohamed S; Awad, Hisham A; El-Gammasy, Tarek M; El-Farghali, Ola G; Sallam, Mohamed T; Shinkar, Dina M

2017-06-01

To evaluate efficacy and safety of delivery room (DR) sustained lung inflation (SLI) in resuscitation of preterm neonates. Randomized Controlled Trial including 112 preterm infants randomized to either SLI (n = 57) using T-piece resuscitator [maximum three inflations with maximum pressure of 30 cmH 2 O for 15 s followed by continuous positive airway pressure (CPAP) of 5-7 cmH 2 O] or conventional bag/mask inflation (CBMI) (n = 55) using traditional self-inflating bag (maximum pressure of 40 cmH 2 O at a rate of 40-60 per min). Failure was defined as the need for DR or first 72 h intubation. Cord and 2-h post-resuscitation blood samples were collected to measure interleukin (IL)-1β and tumor necrosis factor-α levels before and after intervention. SLI was associated with significantly higher success rate compared to CBMI [75.4 versus 54.5%; p = 0.017], lower need for DR intubation [5.3% versus 23.6%; (X 2  =   7.7; p = 0.005)], higher 5-min-Apgar score (median 8 versus 7; p = 0.018), shorter duration on nasal-CPAP (p = 0.017), and non-significantly different air leak (7% versus 11%; p = 0.3) and bronchopulmonary dysplasia rates among survivors (2% versus 11%; p = 0.09). Post-resuscitation IL-1β plasma levels increased significantly in CBMI (p = 0.009) and not in SLI group. Delivery room SLI is more effective than intermittent bag and mask inflation for improving short-term respiratory outcome in preterm infants, without significant adverse effects.

Effects of Random Values for Particle Swarm Optimization Algorithm

Directory of Open Access Journals (Sweden)

Hou-Ping Dai

2018-02-01

Full Text Available Particle swarm optimization (PSO algorithm is generally improved by adaptively adjusting the inertia weight or combining with other evolution algorithms. However, in most modified PSO algorithms, the random values are always generated by uniform distribution in the range of [0, 1]. In this study, the random values, which are generated by uniform distribution in the ranges of [0, 1] and [−1, 1], and Gauss distribution with mean 0 and variance 1 ( U [ 0 , 1 ] , U [ − 1 , 1 ] and G ( 0 , 1 , are respectively used in the standard PSO and linear decreasing inertia weight (LDIW PSO algorithms. For comparison, the deterministic PSO algorithm, in which the random values are set as 0.5, is also investigated in this study. Some benchmark functions and the pressure vessel design problem are selected to test these algorithms with different types of random values in three space dimensions (10, 30, and 100. The experimental results show that the standard PSO and LDIW-PSO algorithms with random values generated by U [ − 1 , 1 ] or G ( 0 , 1 are more likely to avoid falling into local optima and quickly obtain the global optima. This is because the large-scale random values can expand the range of particle velocity to make the particle more likely to escape from local optima and obtain the global optima. Although the random values generated by U [ − 1 , 1 ] or G ( 0 , 1 are beneficial to improve the global searching ability, the local searching ability for a low dimensional practical optimization problem may be decreased due to the finite particles.

Three hours of intermittent hypoxia increases circulating glucose levels in healthy adults.

Science.gov (United States)

Newhouse, Lauren P; Joyner, Michael J; Curry, Timothy B; Laurenti, Marcello C; Man, Chiara Dalla; Cobelli, Claudio; Vella, Adrian; Limberg, Jacqueline K

2017-01-01

An independent association exists between sleep apnea and diabetes. Animal models suggest exposure to intermittent hypoxia, a consequence of sleep apnea, results in altered glucose metabolism and fasting hyperglycemia. However, it is unknown if acute exposure to intermittent hypoxia increases glucose concentrations in nondiabetic humans. We hypothesized plasma glucose would be increased from baseline following 3 h of intermittent hypoxia in healthy humans independent of any effect on insulin sensitivity. Eight (7M/1F, 21-34 years) healthy subjects completed two study visits randomized to 3 h of intermittent hypoxia or continuous normoxia, followed by an oral glucose tolerance test. Intermittent hypoxia consisted of 25 hypoxic events per hour where oxygen saturation (SpO 2 ) was significantly reduced (Normoxia: 97 ± 1%, Hypoxia: 90 ± 2%, P  0.05). In contrast, circulating glucose concentrations were increased after 3 h of intermittent hypoxia when compared to baseline (5.0 ± 0.2 vs. 5.3 ± 0.2 mmol/L, P = 0.01). There were no detectable changes in insulin sensitivity following intermittent hypoxia when compared to continuous normoxia, as assessed by the oral glucose tolerance test (P > 0.05). Circulating glucose is increased after 3 h of intermittent hypoxia in healthy humans, independent of any lasting changes in insulin sensitivity. These novel findings could explain, in part, the high prevalence of diabetes in patients with sleep apnea and warrant future studies to identify underlying mechanisms. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Low nitrous oxide production in intermittent-feed high performance nitritating reactors

DEFF Research Database (Denmark)

Su, Qingxian; Jensen, Malene M.; Smets, Barth F.

Nitrous oxide (N2O) production from autotrophic nitrogen removal processes, especially nitritating systems, is of growing concern. N2O dynamics were characterized and N2O production factors were quantified in two lab-scale intermittent-feed nitritating SBRs. 93 ± 14% of the oxidized ammonium...... was converted to nitrite, with the average total net N2O production of 2.1 ± 0.7% of the ammonium oxidized. Operation with intermittent feeding appears an effective optimization approach to mitigate N2O emissions from nitritating systems. Net N2O production rates transiently increased with a rise in pH after...

A non-inferiority, individually randomized trial of intermittent screening and treatment versus intermittent preventive treatment in the control of malaria in pregnancy

DEFF Research Database (Denmark)

Tagbor, Harry; Cairns, Matthew; Bojang, Kalifa

2015-01-01

BACKGROUND: The efficacy of intermittent preventive treatment for malaria with sulfadoxine-pyrimethamine (IPTp-SP) in pregnancy is threatened in parts of Africa by the emergence and spread of resistance to SP. Intermittent screening with a rapid diagnostic test (RDT) and treatment of positive women...... with malaria parasitemia between routine antenatal clinics (310 vs 182 episodes, rate difference: 49.4 per 1,000 pregnancies [95% CI 30.5, 68.3], but the number of hospital admissions for malaria was similar in the two groups. CONCLUSIONS: Despite low levels of resistance to SP in the study areas, ISTp......-AL performed as well as IPTp-SP. In the absence of an effective alternative medication to SP for IPTp, ISTp-AL is a potential alternative to IPTp in areas where SP resistance is high. It may also have a role in areas where malaria transmission is low and for the prevention of malaria in HIV positive women...

Intermittent Cervical Traction for Treating Neck Pain: A Meta-analysis of Randomized Controlled Trials.

Science.gov (United States)

Yang, Jheng-Dao; Tam, Ka-Wai; Huang, Tsai-Wei; Huang, Shih-Wei; Liou, Tsan-Hon; Chen, Hung-Chou

2017-07-01

A meta-analysis. The aim of this study was to perform a comprehensive search of current literature and conduct a meta-analysis of randomized controlled trials (RCTs) to assess the neck pain relieving effect of intermittent cervical traction (ICT). Neck pain is a common and disabling problem with a high prevalence in general population. It causes a considerable burden on the health care system with a substantial expenditure. ICT is a common component of physical therapy for neck pain in the outpatient clinic. However, the evidence regarding the effectiveness of ICT for neck pain is insufficient. Data were obtained from the PubMed, Cochrane Library, Embase, and Scopus databases from the database inception date to July 02, 2016. RCTs reporting the effects of ICT on neck pain, including those comparing the effects of ICT with those of a placebo treatment, were included. Two reviewers independently reviewed the studies, conducted a risk of bias assessment, and extracted data. The data were pooled in a meta-analysis by using a random-effects model. The meta-analysis included seven RCTs. The results indicated that patients who received ICT for neck pain had significantly lower pain scores than those receiving placebos did immediately after treatment (standardized mean difference = -0.26, 95% confidence interval = -0.46 to -0.07). The pain scores during the follow-up period and the neck disability index scores immediately after treatment and during the follow-up period did not differ significantly. ICT may have a short-term neck pain-relieving effect. Some risks of bias were noted in the included studies, reducing the evidence level of this meta-analysis. Additional high-quality RCTs are required to clarify the long-term effects of ICT on neck pain. 1.

Intermittent hypercapnic hypoxia during sleep does not induce ventilatory long-term facilitation in healthy males.

Science.gov (United States)

Deacon, Naomi L; McEvoy, R Doug; Stadler, Daniel L; Catcheside, Peter G

2017-09-01

Intermittent hypoxia-induced ventilatory neuroplasticity is likely important in obstructive sleep apnea pathophysiology. Although concomitant CO 2 levels and arousal state critically influence neuroplastic effects of intermittent hypoxia, no studies have investigated intermittent hypercapnic hypoxia effects during sleep in humans. Thus the purpose of this study was to investigate if intermittent hypercapnic hypoxia during sleep induces neuroplasticity (ventilatory long-term facilitation and increased chemoreflex responsiveness) in humans. Twelve healthy males were exposed to intermittent hypercapnic hypoxia (24 × 30 s episodes of 3% CO 2 and 3.0 ± 0.2% O 2 ) and intermittent medical air during sleep after 2 wk washout period in a randomized crossover study design. Minute ventilation, end-tidal CO 2 , O 2 saturation, breath timing, upper airway resistance, and genioglossal and diaphragm electromyograms were examined during 10 min of stable stage 2 sleep preceding gas exposure, during gas and intervening room air periods, and throughout 1 h of room air recovery. There were no significant differences between conditions across time to indicate long-term facilitation of ventilation, genioglossal or diaphragm electromyogram activity, and no change in ventilatory response from the first to last gas exposure to suggest any change in chemoreflex responsiveness. These findings contrast with previous intermittent hypoxia studies without intermittent hypercapnia and suggest that the more relevant gas disturbance stimulus of concomitant intermittent hypercapnia frequently occurring in sleep apnea influences acute neuroplastic effects of intermittent hypoxia. These findings highlight the need for further studies of intermittent hypercapnic hypoxia during sleep to clarify the role of ventilatory neuroplasticity in the pathophysiology of sleep apnea. NEW & NOTEWORTHY Both arousal state and concomitant CO 2 levels are known modulators of the effects of intermittent hypoxia on

Autonomous change of behavior for environmental context: An intermittent search model with misunderstanding search pattern

Science.gov (United States)

Murakami, Hisashi; Gunji, Yukio-Pegio

2017-07-01

Although foraging patterns have long been predicted to optimally adapt to environmental conditions, empirical evidence has been found in recent years. This evidence suggests that the search strategy of animals is open to change so that animals can flexibly respond to their environment. In this study, we began with a simple computational model that possesses the principal features of an intermittent strategy, i.e., careful local searches separated by longer steps, as a mechanism for relocation, where an agent in the model follows a rule to switch between two phases, but it could misunderstand this rule, i.e., the agent follows an ambiguous switching rule. Thanks to this ambiguity, the agent's foraging strategy can continuously change. First, we demonstrate that our model can exhibit an optimal change of strategy from Brownian-type to Lévy-type depending on the prey density, and we investigate the distribution of time intervals for switching between the phases. Moreover, we show that the model can display higher search efficiency than a correlated random walk.

Intermittent Explosive Disorder

Directory of Open Access Journals (Sweden)

Lut Tamam

2011-09-01

Full Text Available Intermittent explosive disorder is an impulse control disorder characterized by the occurrence of discrete episodes of failure to resist aggressive impulses that result in violent assault or destruction of property. Though the prevalence intermittent explosive disorder has been reported to be relatively rare in frontier studies on the field, it is now common opinion that intermittent explosive disorder is far more common than previously thought especially in clinical psychiatry settings. Etiological studies displayed the role of both psychosocial factors like childhood traumas and biological factors like dysfunctional neurotransmitter systems and genetics. In differential diagnosis of the disorder, disorders involving agression as a symptom such as alcohol and drug intoxication, antisocial and borderline personality disorders, personality changes due to general medical conditions and behavioral disorder should be considered. A combination of pharmacological and psychotherapeutic approaches are suggested in the treatment of the disorder. This article briefly reviews the historical background, diagnostic criteria, epidemiology, etiology and treatment of intermittent explosive disorder.

Ultra-Short-Term Wind-Power Forecasting Based on the Weighted Random Forest Optimized by the Niche Immune Lion Algorithm

Directory of Open Access Journals (Sweden)

Dongxiao Niu

2018-04-01

Full Text Available The continuous increase in energy consumption has made the potential of wind-power generation tremendous. However, the obvious intermittency and randomness of wind speed results in the fluctuation of the output power in a wind farm, seriously affecting the power quality. Therefore, the accurate prediction of wind power in advance can improve the ability of wind-power integration and enhance the reliability of the power system. In this paper, a model of wavelet decomposition (WD and weighted random forest (WRF optimized by the niche immune lion algorithm (NILA-WRF is presented for ultra-short-term wind power prediction. Firstly, the original serials of wind speed and power are decomposed into several sub-serials by WD because the original serials have no obvious day characteristics. Then, the model parameters are set and the model trained with the sub-serials of wind speed and wind power decomposed. Finally, the WD-NILA-WRF model is used to predict the wind power of the relative sub-serials and the result is reconstructed to obtain the final prediction result. The WD-NILA-WRF model combines the advantage of each single model, which uses WD for signal de-noising, and uses the niche immune lion algorithm (NILA to improve the model’s optimization efficiency. In this paper, two empirical analyses are carried out to prove the accuracy of the model, and the experimental results verify the proposed model’s validity and superiority compared with the back propagation neural network (BP neural network, support vector machine (SVM, RF and NILA-RF, indicating that the proposed method is superior in cases influenced by noise and unstable factors, and possesses an excellent generalization ability and robustness.

Filling of a Poisson trap by a population of random intermittent searchers

KAUST Repository

Bressloff, Paul C.

2012-03-01

We extend the continuum theory of random intermittent search processes to the case of N independent searchers looking to deliver cargo to a single hidden target located somewhere on a semi-infinite track. Each searcher randomly switches between a stationary state and either a leftward or rightward constant velocity state. We assume that all of the particles start at one end of the track and realize sample trajectories independently generated from the same underlying stochastic process. The hidden target is treated as a partially absorbing trap in which a particle can only detect the target and deliver its cargo if it is stationary and within range of the target; the particle is removed from the system after delivering its cargo. As a further generalization of previous models, we assume that up to n successive particles can find the target and deliver its cargo. Assuming that the rate of target detection scales as 1/N, we show that there exists a well-defined mean-field limit N→ in which the stochastic model reduces to a deterministic system of linear reaction-hyperbolic equations for the concentrations of particles in each of the internal states. These equations decouple from the stochastic process associated with filling the target with cargo. The latter can be modeled as a Poisson process in which the time-dependent rate of filling λ(t) depends on the concentration of stationary particles within the target domain. Hence, we refer to the target as a Poisson trap. We analyze the efficiency of filling the Poisson trap with n particles in terms of the waiting time density f n(t). The latter is determined by the integrated Poisson rate μ(t)=0tλ(s)ds, which in turn depends on the solution to the reaction-hyperbolic equations. We obtain an approximate solution for the particle concentrations by reducing the system of reaction-hyperbolic equations to a scalar advection-diffusion equation using a quasisteady-state analysis. We compare our analytical results for the

Understanding Adherence to Daily and Intermittent Regimens of Oral HIV Pre-exposure Prophylaxis Among Men Who Have Sex with Men in Kenya

OpenAIRE

Mugo, Peter Mwangi; Sanders, Eduard J.; Mutua, Gaudensia; van der Elst, Elisabeth; Anzala, Omu; Barin, Burc; Bangsberg, David R.; Priddy, Frances H.; Haberer, Jessica E.

2014-01-01

A qualitative assessment of Kenyan men who have sex with men taking daily and intermittent oral HIV pre-exposure prophylaxis (PrEP) found stigma, sex work, mobility, and alcohol impacted adherence. We analyzed quantitative data from the same cohort to explore different definitions of intermittent adherence. Volunteers were randomized to daily emtricitabine/tenofovir or placebo, or intermittent (prescription: Mondays/Fridays/after sex, maximum 1 dose/day) emtricitabine/tenofovir or placebo (2:...

Preventive maintenance optimization for a stochastically degrading system with a random initial age

International Nuclear Information System (INIS)

Sidibe, I.B.; Khatab, A.; Diallo, C.; Kassambara, A.

2017-01-01

This paper investigates the optimal age replacement policy for used systems, such as second-hand products, which start their second life-cycle in a more severe environment with an initial age that is uncertain. This uncertain age is modelled as a random variable following continuous probability distributions. A mathematical model is developed to minimize the total expected cost per unit of time for these systems on an infinite time horizon. Optimality and existence conditions for a unique optimal solution are derived and used in a numerical procedure to solve the problem. Numerical experiments are provided to demonstrate the added value and the impacts of the random initial age on the optimal replacement policy.

Optimization by GRASP greedy randomized adaptive search procedures

CERN Document Server

Resende, Mauricio G C

2016-01-01

This is the first book to cover GRASP (Greedy Randomized Adaptive Search Procedures), a metaheuristic that has enjoyed wide success in practice with a broad range of applications to real-world combinatorial optimization problems. The state-of-the-art coverage and carefully crafted pedagogical style lends this book highly accessible as an introductory text not only to GRASP, but also to combinatorial optimization, greedy algorithms, local search, and path-relinking, as well as to heuristics and metaheuristics, in general. The focus is on algorithmic and computational aspects of applied optimization with GRASP with emphasis given to the end-user, providing sufficient information on the broad spectrum of advances in applied optimization with GRASP. For the more advanced reader, chapters on hybridization with path-relinking and parallel and continuous GRASP present these topics in a clear and concise fashion. Additionally, the book offers a very complete annotated bibliography of GRASP and combinatorial optimizat...

A botanical compound, Padma 28, increases walking distance in stable intermittent claudication

DEFF Research Database (Denmark)

Drabaek, H; Mehlsen, J; Himmelstrup, H

1993-01-01

Thirty-six patients with a median age of sixty-seven years and a median duration of intermittent claudication of five years were randomized to either active treatment with Padma 28 or placebo. The effect of treatment was quantified by measurements of systemic and peripheral systolic blood pressur...

Stochastic Optimal Estimation with Fuzzy Random Variables and Fuzzy Kalman Filtering

Institute of Scientific and Technical Information of China (English)

FENG Yu-hu

2005-01-01

By constructing a mean-square performance index in the case of fuzzy random variable, the optimal estimation theorem for unknown fuzzy state using the fuzzy observation data are given. The state and output of linear discrete-time dynamic fuzzy system with Gaussian noise are Gaussian fuzzy random variable sequences. An approach to fuzzy Kalman filtering is discussed. Fuzzy Kalman filtering contains two parts: a real-valued non-random recurrence equation and the standard Kalman filtering.

Noise-sustained structure, Intermittency, and the Ginzburg--Landau equation

International Nuclear Information System (INIS)

Deissler, R.J.

1985-01-01

The time-dependent generalized Ginzburg--Landau equation is an equation that is related to many physical systems. Solutions of this equation in the presence of low-level external noise are studied. Numerical solutions of this equation in the stationary frame of refernce and with nonzero group velocity that is greater than a critical velocity exhibit a selective spatial amplification of noise resulting in spatially growing waves. These waves in turn result in the formation of a dynamic structure. It is found that the microscopic noise plays an importuant role in the macroscopic dynamics of the system. For certain parameter values the system exhibits intermittent turbulent behavior in which the random nature of the external noise plays a crucial role. A mechanism which may be responsible for the intermittent turbulence occurring in some fluid systems is suggested

Intermittent heating of buildings

Energy Technology Data Exchange (ETDEWEB)

Kohonen, K

1983-02-01

Conditions for intermittent heating of buildings are considered both theoretically and experimentally. Thermal behaviour of buildings adn rooms in intermittent heating is simulated by a program based on the convective heat balance equation and by simplified RC-models. The preheat times and the heating energy savings compared with continuous heating are presented for typical lightweight, mediumweight and heavyweight classroom and office modules. Formulaes for estimating the oversizing of the radiator network, the maximum heat output of heat exchangers in district heating and the efficiency of heating boilers in intermittent heating are presented. The preheat times and heating energy savings with different heating control systems are determined also experimentally in eight existing buildings. In addition some principles for the planning and application of intermittent heating systems are suggested.

Adductor Canal Block With Continuous Infusion Versus Intermittent Boluses and Morphine Consumption

DEFF Research Database (Denmark)

Jaeger, Pia; Baggesgaard, Jonas; Sørensen, Johan K

2018-01-01

a randomized, blinded, controlled study, including patients scheduled for total knee arthroplasty with spinal anesthesia. Patients received 0.2% ropivacaine via a catheter in the adductor canal administered as either repeated intermittent boluses (21 mL/3 h) or continuous infusion (7 mL/h). The primary outcome...

Randomized controlled trial comparing nasal intermittent positive pressure ventilation and nasal continuous positive airway pressure in premature infants after tracheal extubation

Directory of Open Access Journals (Sweden)

Daniela Franco Rizzo Komatsu

Full Text Available Summary Objective: To analyze the frequency of extubation failure in premature infants using conventional mechanical ventilation (MV after extubation in groups subjected to nasal intermittent positive pressure ventilation (nIPPV and continuous positive airway pressure (nCPAP. Method: Seventy-two premature infants with respiratory failure were studied, with a gestational age (GA ≤ 36 weeks and birth weight (BW > 750 g, who required tracheal intubation and mechanical ventilation. The study was controlled and randomized in order to ensure that the members of the groups used in the research were chosen at random. Randomization was performed at the time of extubation using sealed envelopes. Extubation failure was defined as the need for re-intubation and mechanical ventilation during the first 72 hours after extubation. Results: Among the 36 premature infants randomized to nIPPV, six (16.6% presented extubation failure in comparison to 11 (30.5% of the 36 premature infants randomized to nCPAP. There was no statistical difference between the two study groups regarding BW, GA, classification of the premature infant, and MV time. The main cause of extubation failure was the occurrence of apnea. Gastrointestinal and neurological complications did not occur in the premature infants participating in the study. Conclusion: We found that, despite the extubation failure of the group of premature infants submitted to nIPPV being numerically smaller than in premature infants submitted to nCPAP, there was no statistically significant difference between the two modes of ventilatory support after extubation.

Impact of intermittent fasting on glucose homeostasis.

Science.gov (United States)

Varady, Krista A

2016-07-01

This article provides an overview of the most recent human trials that have examined the impact of intermittent fasting on glucose homeostasis. Our literature search retrieved one human trial of alternate day fasting, and three trials of Ramadan fasting published in the past 12 months. Current evidence suggests that 8 weeks of alternate day fasting that produces mild weight loss (4% from baseline) has no effect on glucose homeostasis. As for Ramadan fasting, decreases in fasting glucose, insulin, and insulin resistance have been noted after 4 weeks in healthy normal weight individuals with mild weight loss (1-2% from baseline). However, Ramadan fasting may have little impact on glucoregulatory parameters in women with polycystic ovarian syndrome who failed to observe weight loss. Whether intermittent fasting is an effective means of regulating glucose homeostasis remains unclear because of the scarcity of studies in this area. Large-scale, longer-term randomized controlled trials will be required before the use of fasting can be recommended for the prevention and treatment of metabolic diseases.

Protective effect of intermittent fasting on the mortality of gamma-irradiated mice

International Nuclear Information System (INIS)

Kozubik, A.; Pospisil, M.

1982-01-01

The effect of 1 to 6 weeks' adaptation to intermittent fasting (alternating periods of 24 h fasting and subsequent 24 h feeding) on the manifestations of radioresistance of mice subjected to whole-body gamma-irradiation was studied. A favourable effect of this feeding regimen on the survival of irradiated animals was observed. The optimal redioprotective effect was achieved in mice adapted to intermittent fasting for 2 to 3 weeks and irradiated after 24 h of food intake. Furthermore, it was shown that the radioresistance of the adapted organism depends on the momentary state of food intake. After renewal of the normal ad libitum feeding the adaptively induced radioresistance decreases. (orig.) [de

Protective effect of intermittent fasting on the mortality of gamma-irradiated mice

Energy Technology Data Exchange (ETDEWEB)

Kozubik, A.; Pospisil, M.

1982-12-01

The effect of 1 to 6 weeks' adaptation to intermittent fasting (alternating periods of 24 h fasting and subsequent 24 h feeding) on the manifestations of radioresistance of mice subjected to whole-body gamma-irradiation was studied. A favourable effect of this feeding regimen on the survival of irradiated animals was observed. The optimal redioprotective effect was achieved in mice adapted to intermittent fasting for 2 to 3 weeks and irradiated after 24 h of food intake. Furthermore, it was shown that the radioresistance of the adapted organism depends on the momentary state of food intake. After renewal of the normal ad libitum feeding the adaptively induced radioresistance decreases.

Protective effect of intermittent fasting on the mortality of gamma-irradiated mice

Energy Technology Data Exchange (ETDEWEB)

Kozubik, A; Pospisil, M

1982-12-01

The effect of 1 to 6 weeks' adaptation to intermittent fasting (alternating periods of 24 h fasting and subsequent 24 h feeding) on the manifestations of radioresistance of mice subjected to whole-body gamma-irradiation was studied. A favourable effect of this feeding regimen on the survival of irradiated animals was observed. The optimal redioprotective effect was achieved in mice adapted to intermittent fasting for 2 to 3 weeks and irradiated after 24 h of food intake. Furthermore, it was shown that the radioresistance of the adapted organism depends on the momentary state of food intake. After renewal of the normal ad libitum feeding the adaptively induced radioresistance decreases.

Multidimensional intermittency in hadronic collisions

International Nuclear Information System (INIS)

Pan, J.; Hwa, R.C.

1992-06-01

The study of intermittency in high-energy hadronic collisions by the Monte Carlo code ECCO is extended to 3-dimensional phase space. Strong intermittency is found in agreement with the data. Fluctuation in the impact parameter is responsible for the intermittency in lnp T , and the transverse-momentum conservation leads to negative intermittency slopes in the azimuthal angle φ. The Ochs-Wosiek plots are linear in all dimensions having universal slopes. An exponent ν = 1.448 emerges to characterize multiparticle production in pp collisions. The properties of G moments are also examined, and the fractal dimensions determined

On the effect of intermittency of turbulence on the parabolic relation between skewness and kurtosis in magnetized plasmas

Energy Technology Data Exchange (ETDEWEB)

Guszejnov, Dávid; Lazányi, Nóra [Department of Nuclear Techniques, Budapest University of Technology and Economics, Association EURATOM, Műegyetem rkp. 9., H-1111 Budapest (Hungary); Bencze, Attila; Zoletnik, Sándor [MTA Wigner RCP, EURATOM Association, PO Box 49, H-1525 Budapest (Hungary)

2013-11-15

This paper is aimed to contribute to the scientific discussions that have been triggered by the experimental observation of a quadratic relation between the kurtosis and skewness of turbulent fluctuations present in fusion plasmas and other nonlinear physical systems. In this paper, we offer a general statistical model which attributes the observed K=aS{sup 2}+b relation to the varying intermittency of the experimental signals. The model is a two random variable model constructed to catch the essential intermittent feature of the real signal. One of the variables is the amplitude of the underlying intermittent event (e.g., turbulent structure) while the other is connected to the intermittency level of the system. This simple model can attribute physical meaning to the a and b coefficients, as they characterize the spatio-temporal statistics of intermittent events. By constructing a particle-conserving Gaussian model for the underlying coherent structures, the experimentally measured a and b coefficients could be adequately reproduced.

On the effect of intermittency of turbulence on the parabolic relation between skewness and kurtosis in magnetized plasmas

International Nuclear Information System (INIS)

Guszejnov, Dávid; Lazányi, Nóra; Bencze, Attila; Zoletnik, Sándor

2013-01-01

This paper is aimed to contribute to the scientific discussions that have been triggered by the experimental observation of a quadratic relation between the kurtosis and skewness of turbulent fluctuations present in fusion plasmas and other nonlinear physical systems. In this paper, we offer a general statistical model which attributes the observed K=aS 2 +b relation to the varying intermittency of the experimental signals. The model is a two random variable model constructed to catch the essential intermittent feature of the real signal. One of the variables is the amplitude of the underlying intermittent event (e.g., turbulent structure) while the other is connected to the intermittency level of the system. This simple model can attribute physical meaning to the a and b coefficients, as they characterize the spatio-temporal statistics of intermittent events. By constructing a particle-conserving Gaussian model for the underlying coherent structures, the experimentally measured a and b coefficients could be adequately reproduced

Remote optimal state estimation over communication channels with random delays

KAUST Repository

Mahmoud, Magdi S.; Al-Sunni, Fouad; Liu, Bo

2014-01-01

This paper considers the optimal estimation of linear systems over unreliable communication channels with random delays. In this work, it is assumed that the system to be estimated is far away from the filter. The observations of the system

Observation of a Pomeau-Manneville intermittent route to chaos in a nonlinear oscillator

International Nuclear Information System (INIS)

Jeffries, C.; Perez, J.

1982-01-01

For a driven nonlinear semiconductor oscillator which shows a period-doubling pitchfork bifurcation route to chaos, we report an additional route to chaos: the Pomeau-Manneville intermittency route, characterized by a periodic (laminar) phase interrupted by bursts of aperiodic behavior. This occurs near a tangent bifurcation as the system driving parameter is reduced by epsilon from the threshold value for a periodic window. Data are presented for the dependence of the average laminar length on epsilon, and also on additive random noise voltage. The results are in reasonable agreement with the intermittency theory of Hirsch, Huberman, and Scalapino. The distribution P(l) is also reported

Intermittency in branching models

International Nuclear Information System (INIS)

Chiu, C.B.; Texas Univ., Austin; Hwa, R.C.; Oregon Univ., Eugene

1990-01-01

The intermittency properties of three branching models have been investigated. The factorial moments show power-law behavior as function of small rapidity width. The slopes and energy dependences reveal different characteristics of the models. The gluon model has the weakest intermittency. (orig.)

THE EFFECT OF INTERMITTENT GYRO-SCALE SLAB TURBULENCE ON PARALLEL AND PERPENDICULAR COSMIC-RAY TRANSPORT

International Nuclear Information System (INIS)

Le Roux, J. A.

2011-01-01

Earlier work based on nonlinear guiding center (NLGC) theory suggested that perpendicular cosmic-ray transport is diffusive when cosmic rays encounter random three-dimensional magnetohydrodynamic turbulence dominated by uniform two-dimensional (2D) turbulence with a minor uniform slab turbulence component. In this approach large-scale perpendicular cosmic-ray transport is due to cosmic rays microscopically diffusing along the meandering magnetic field dominated by 2D turbulence because of gyroresonant interactions with slab turbulence. However, turbulence in the solar wind is intermittent and it has been suggested that intermittent turbulence might be responsible for the observation of 'dropout' events in solar energetic particle fluxes on small scales. In a previous paper le Roux et al. suggested, using NLGC theory as a basis, that if gyro-scale slab turbulence is intermittent, large-scale perpendicular cosmic-ray transport in weak uniform 2D turbulence will be superdiffusive or subdiffusive depending on the statistical characteristics of the intermittent slab turbulence. In this paper we expand and refine our previous work further by investigating how both parallel and perpendicular transport are affected by intermittent slab turbulence for weak as well as strong uniform 2D turbulence. The main new finding is that both parallel and perpendicular transport are the net effect of an interplay between diffusive and nondiffusive (superdiffusive or subdiffusive) transport effects as a consequence of this intermittency.

THE EFFECT OF INTERMITTENT GYRO-SCALE SLAB TURBULENCE ON PARALLEL AND PERPENDICULAR COSMIC-RAY TRANSPORT

Energy Technology Data Exchange (ETDEWEB)

Le Roux, J. A. [Department of Physics, University of Alabama in Huntsville, Huntsville, AL 35899 (United States)

2011-12-10

Earlier work based on nonlinear guiding center (NLGC) theory suggested that perpendicular cosmic-ray transport is diffusive when cosmic rays encounter random three-dimensional magnetohydrodynamic turbulence dominated by uniform two-dimensional (2D) turbulence with a minor uniform slab turbulence component. In this approach large-scale perpendicular cosmic-ray transport is due to cosmic rays microscopically diffusing along the meandering magnetic field dominated by 2D turbulence because of gyroresonant interactions with slab turbulence. However, turbulence in the solar wind is intermittent and it has been suggested that intermittent turbulence might be responsible for the observation of 'dropout' events in solar energetic particle fluxes on small scales. In a previous paper le Roux et al. suggested, using NLGC theory as a basis, that if gyro-scale slab turbulence is intermittent, large-scale perpendicular cosmic-ray transport in weak uniform 2D turbulence will be superdiffusive or subdiffusive depending on the statistical characteristics of the intermittent slab turbulence. In this paper we expand and refine our previous work further by investigating how both parallel and perpendicular transport are affected by intermittent slab turbulence for weak as well as strong uniform 2D turbulence. The main new finding is that both parallel and perpendicular transport are the net effect of an interplay between diffusive and nondiffusive (superdiffusive or subdiffusive) transport effects as a consequence of this intermittency.

Stochastic optimal foraging: tuning intensive and extensive dynamics in random searches.

Directory of Open Access Journals (Sweden)

Frederic Bartumeus

Full Text Available Recent theoretical developments had laid down the proper mathematical means to understand how the structural complexity of search patterns may improve foraging efficiency. Under information-deprived scenarios and specific landscape configurations, Lévy walks and flights are known to lead to high search efficiencies. Based on a one-dimensional comparative analysis we show a mechanism by which, at random, a searcher can optimize the encounter with close and distant targets. The mechanism consists of combining an optimal diffusivity (optimally enhanced diffusion with a minimal diffusion constant. In such a way the search dynamics adequately balances the tension between finding close and distant targets, while, at the same time, shifts the optimal balance towards relatively larger close-to-distant target encounter ratios. We find that introducing a multiscale set of reorientations ensures both a thorough local space exploration without oversampling and a fast spreading dynamics at the large scale. Lévy reorientation patterns account for these properties but other reorientation strategies providing similar statistical signatures can mimic or achieve comparable efficiencies. Hence, the present work unveils general mechanisms underlying efficient random search, beyond the Lévy model. Our results suggest that animals could tune key statistical movement properties (e.g. enhanced diffusivity, minimal diffusion constant to cope with the very general problem of balancing out intensive and extensive random searching. We believe that theoretical developments to mechanistically understand stochastic search strategies, such as the one here proposed, are crucial to develop an empirically verifiable and comprehensive animal foraging theory.

An optimal inspection strategy for randomly failing equipment

International Nuclear Information System (INIS)

Chelbi, Anis; Ait-Kadi, Daoud

1999-01-01

This paper addresses the problem of generating optimal inspection strategies for randomly failing equipment where imminent failure is not obvious and can only be detected through inspection. Inspections are carried out following a condition-based procedure. The equipment is replaced if it has failed or if it shows imminent signs of failure. The latter state is indicated by measuring certain predetermined control parameters during inspection. Costs are associated with inspection, idle time and preventive or corrective actions. An optimal inspection strategy is defined as the inspection sequence minimizing the expected total cost per time unit over an infinite span. A mathematical model and a numerical algorithm are developed to generate an optimal inspection sequence. As a practical example, the model is applied to provide a machine tool operator with a time sequence for inspecting the cutting tool. The tool life time distribution and the trend of one control parameter defining its actual condition are supposed to be known

Metabolic Effects of Intermittent Fasting.

Science.gov (United States)

Patterson, Ruth E; Sears, Dorothy D

2017-08-21

The objective of this review is to provide an overview of intermittent fasting regimens, summarize the evidence on the health benefits of intermittent fasting, and discuss physiological mechanisms by which intermittent fasting might lead to improved health outcomes. A MEDLINE search was performed using PubMed and the terms "intermittent fasting," "fasting," "time-restricted feeding," and "food timing." Modified fasting regimens appear to promote weight loss and may improve metabolic health. Several lines of evidence also support the hypothesis that eating patterns that reduce or eliminate nighttime eating and prolong nightly fasting intervals may result in sustained improvements in human health. Intermittent fasting regimens are hypothesized to influence metabolic regulation via effects on (a) circadian biology, (b) the gut microbiome, and (c) modifiable lifestyle behaviors, such as sleep. If proven to be efficacious, these eating regimens offer promising nonpharmacological approaches to improving health at the population level, with multiple public health benefits.

Fluctuation relations with intermittent non-Gaussian variables.

Science.gov (United States)

Budini, Adrián A

2011-12-01

Nonequilibrium stationary fluctuations may exhibit a special symmetry called fluctuation relations (FRs). Here, we show that this property is always satisfied by the subtraction of two random and independent variables related by a thermodynamiclike change of measure. Taking one of them as a modulated Poisson process, it is demonstrated that intermittence and FRs are compatible properties that may coexist naturally. Strong non-Gaussian features characterize the probability distribution and its generating function. Their associated large deviation functions develop a "kink" at the origin and a plateau regime respectively. Application of this model in different stationary nonequilibrium situations is discussed.

Impact of intermittent fasting on the lipid profile: Assessment associated with diet and weight loss.

Science.gov (United States)

Santos, Heitor O; Macedo, Rodrigo C O

2018-04-01

Intermittent fasting, whose proposed benefits include the improvement of lipid profile and the body weight loss, has gained considerable scientific and popular repercussion. This review aimed to consolidate studies that analyzed the lipid profile in humans before and after intermittent fasting period through a detailed review; and to propose the physiological mechanism, considering the diet and the body weight loss. Normocaloric and hypocaloric intermittent fasting may be a dietary method to aid in the improvement of the lipid profile in healthy, obese and dyslipidemic men and women by reducing total cholesterol, LDL, triglycerides and increasing HDL levels. However, the majority of studies that analyze the intermittent fasting impacts on the lipid profile and body weight loss are observational based on Ramadan fasting, which lacks large sample and detailed information about diet. Randomized clinical trials with a larger sample size are needed to evaluate the IF effects mainly in patients with dyslipidemia. Copyright © 2018 European Society for Clinical Nutrition and Metabolism. Published by Elsevier Ltd. All rights reserved.

Water quality effects of intermittent water supply in Arraiján, Panama.

Science.gov (United States)

Erickson, John J; Smith, Charlotte D; Goodridge, Amador; Nelson, Kara L

2017-05-01

Intermittent drinking water supply is common in low- and middle-income countries throughout the world and can cause water quality to degrade in the distribution system. In this study, we characterized water quality in one study zone with continuous supply and three zones with intermittent supply in the drinking water distribution network in Arraiján, Panama. Low or zero pressures occurred in all zones, and negative pressures occurred in the continuous zone and two of the intermittent zones. Despite hydraulic conditions that created risks for backflow and contaminant intrusion, only four of 423 (0.9%) grab samples collected at random times were positive for total coliform bacteria and only one was positive for E. coli. Only nine of 496 (1.8%) samples had turbidity >1.0 NTU and all samples had ≥0.2 mg/L free chlorine residual. In contrast, water quality was often degraded during the first-flush period (when supply first returned after an outage). Still, routine and first-flush water quality under intermittent supply was much better in Arraiján than that reported in a previous study conducted in India. Better water quality in Arraiján could be due to better water quality leaving the treatment plant, shorter supply outages, higher supply pressures, a more consistent and higher chlorine residual, and fewer contaminant sources near pipes. The results illustrate that intermittent supply and its effects on water quality can vary greatly between and within distribution networks. The study also demonstrated that monitoring techniques designed specifically for intermittent supply, such as continuous pressure monitoring and sampling the first flush, can detect water quality threats and degradation that would not likely be detected with conventional monitoring. Copyright © 2017 Elsevier Ltd. All rights reserved.

Emergence of an optimal search strategy from a simple random walk.

Science.gov (United States)

Sakiyama, Tomoko; Gunji, Yukio-Pegio

2013-09-06

In reports addressing animal foraging strategies, it has been stated that Lévy-like algorithms represent an optimal search strategy in an unknown environment, because of their super-diffusion properties and power-law-distributed step lengths. Here, starting with a simple random walk algorithm, which offers the agent a randomly determined direction at each time step with a fixed move length, we investigated how flexible exploration is achieved if an agent alters its randomly determined next step forward and the rule that controls its random movement based on its own directional moving experiences. We showed that our algorithm led to an effective food-searching performance compared with a simple random walk algorithm and exhibited super-diffusion properties, despite the uniform step lengths. Moreover, our algorithm exhibited a power-law distribution independent of uniform step lengths.

A Randomized Exchange Algorithm for Computing Optimal Approximate Designs of Experiments

KAUST Repository

Harman, Radoslav; Filová , Lenka; Richtarik, Peter

2018-01-01

We propose a class of subspace ascent methods for computing optimal approximate designs that covers both existing as well as new and more efficient algorithms. Within this class of methods, we construct a simple, randomized exchange algorithm (REX). Numerical comparisons suggest that the performance of REX is comparable or superior to the performance of state-of-the-art methods across a broad range of problem structures and sizes. We focus on the most commonly used criterion of D-optimality that also has applications beyond experimental design, such as the construction of the minimum volume ellipsoid containing a given set of data-points. For D-optimality, we prove that the proposed algorithm converges to the optimum. We also provide formulas for the optimal exchange of weights in the case of the criterion of A-optimality. These formulas enable one to use REX for computing A-optimal and I-optimal designs.

A Randomized Exchange Algorithm for Computing Optimal Approximate Designs of Experiments

KAUST Repository

Harman, Radoslav

2018-01-17

We propose a class of subspace ascent methods for computing optimal approximate designs that covers both existing as well as new and more efficient algorithms. Within this class of methods, we construct a simple, randomized exchange algorithm (REX). Numerical comparisons suggest that the performance of REX is comparable or superior to the performance of state-of-the-art methods across a broad range of problem structures and sizes. We focus on the most commonly used criterion of D-optimality that also has applications beyond experimental design, such as the construction of the minimum volume ellipsoid containing a given set of data-points. For D-optimality, we prove that the proposed algorithm converges to the optimum. We also provide formulas for the optimal exchange of weights in the case of the criterion of A-optimality. These formulas enable one to use REX for computing A-optimal and I-optimal designs.

The effects of intermittent, CD4-guided antiretroviral therapy on body composition and metabolic parameters

NARCIS (Netherlands)

Martinez, Esteban; Visnegarwala, Fehmida; Grund, Birgit; Thomas, Avis; Gibert, Cynthia; Shlay, Judith; Drummond, Fraser; Pearce, Daniel; Edwards, Simon; Reiss, Peter; El-Sadr, Wafaa; Carr, Andrew

2010-01-01

Objective: To assess the effects of decreased antiretroviral therapy exposure on body fat and metabolic parameters. Design: Substudy of the Strategies for Management of Anti-Retroviral Therapy study, in which participants were randomized to intermittent CD4-guided [Drug Conservation (DC) group] or

Naftidrofuryl for intermittent claudication.

Science.gov (United States)

De Backer, T L M; Vander Stichele, R; Lehert, P; Van Bortel, L

2008-04-16

Lifestyle changes and cardiovascular prevention measures are a primary treatment for intermittent claudication (IC). Symptomatic treatment with vasoactive agents (Anatomic Therapeutic Chemical Classification (ATC) for medicines from the World Health Organisation class CO4A) is controversial. To evaluate evidence on the efficacy and safety of oral naftidrofuryl (ATC CO4 21) versus placebo on the pain-free walking distance (PFWD) of people with IC by using a meta-analysis based on individual patient data (IPD). The Cochrane Peripheral Vascular Diseases Group searched their Trials Register (last searched December 2007) and CENTRAL (last searched 2007, Issue 4). We searched MEDLINE, EMBASE, International Pharmaceutical Abstracts, the Science Citation Index and contacted the authors and checked the reference lists of retrieved articles. We asked the manufacturing company for IPD. We included only randomized controlled trials (RCTs) with low or moderate risk of bias for which the IPD were available. We collected data from the electronic data file or from the case report form and checked the data by a statistical quality control procedure. All randomized patients were analyzed following the intention-to-treat (ITT) principle. The geometric mean of the relative improvement in PFWD was calculated for both treatment groups in all identified studies. The effect of the drug was assessed compared with placebo on final walking distance (WDf) using multilevel and random-effect models and adjusting for baseline walking distance (WD0). For the responder analysis, therapeutic success was defined as an improvement of walking distance of at least 50%. We included seven studies in the IPD (n = 1266 patients). One of these studies (n = 183) was only used in the sensitivity analysis so that the main analysis included 1083 patients. The ratio of the relative improvement in PFWD (naftidrofuryl compared with placebo) was 1.37 (95% confidence interval (CI) 1.32 to 1.51, P < 0.001). The

A randomized trial of automated intermittent ropivacaine administration vs. continuous infusion in an interscalene catheter

DEFF Research Database (Denmark)

Oxlund, J; Clausen, A H; Venø, S

2018-01-01

. Patients were allocated to either automated intermittent boluses with 16 mg ropivacaine every 2 h combined with patient-controlled administration or to a conventional regimen of continuous infusion of 8 mg/h (4 ml/h) of ropivacaine combined with patient controlled administration (2 ml, lockout time 30 min...

A new logistic dynamic particle swarm optimization algorithm based on random topology.

Science.gov (United States)

Ni, Qingjian; Deng, Jianming

2013-01-01

Population topology of particle swarm optimization (PSO) will directly affect the dissemination of optimal information during the evolutionary process and will have a significant impact on the performance of PSO. Classic static population topologies are usually used in PSO, such as fully connected topology, ring topology, star topology, and square topology. In this paper, the performance of PSO with the proposed random topologies is analyzed, and the relationship between population topology and the performance of PSO is also explored from the perspective of graph theory characteristics in population topologies. Further, in a relatively new PSO variant which named logistic dynamic particle optimization, an extensive simulation study is presented to discuss the effectiveness of the random topology and the design strategies of population topology. Finally, the experimental data are analyzed and discussed. And about the design and use of population topology on PSO, some useful conclusions are proposed which can provide a basis for further discussion and research.

Intermittent fasting in Type 2 diabetes mellitus and the risk of hypoglycaemia: a randomized controlled trial.

Science.gov (United States)

Corley, B T; Carroll, R W; Hall, R M; Weatherall, M; Parry-Strong, A; Krebs, J D

2018-05-01

To establish whether the risk of hypoglycaemia is greater with 2 consecutive days of very-low-calorie diet compared with 2 non-consecutive days of very-low-calorie diet in people with Type 2 diabetes. This was a non-blinded randomized parallel group interventional trial of intermittent fasting in adults. The participants had a BMI of 30-45 kg/m 2 , Type 2 diabetes treated with metformin and/or hypoglycaemic medications and an HbA 1c concentration of 50-86 mmol/mol (6.7-10%). The participants followed a 2092-2510-kJ diet on 2 days per week for 12 weeks. A total of 41 participants were randomized 1:1 to consecutive (n=19) or non-consecutive (n=22) day fasts, of whom 37 (n=18 and n=19, respectively) were included in the final analysis. The primary outcome was difference in the rate of hypoglycaemia between the two study arms. Secondary outcomes included change in diet, quality of life, weight, lipid, glucose and HbA 1c levels, and liver function. The mean hypoglycaemia rate was 1.4 events over 12 weeks. Fasting increased the rate of hypoglycaemia despite medication reduction (RR 2.05, 95% CI 1.17 to 3.52). There was no difference between fasting on consecutive days and fasting on non-consecutive days (RR 1.54, 95% CI 0.35 to 6.11). Improvements in weight, HbA 1c , fasting glucose and quality of life were experienced by participants in both arms. In individuals with Type 2 diabetes on hypoglycaemic medications, fasting of any type increased the rate of hypoglycaemia. With education and medication reduction, fewer than expected hypoglycaemic events occurred. Although it was not possible to determine whether fasting on consecutive days increased the risk of hypoglycaemia, an acceptable rate was observed in both arms. © 2018 Diabetes UK.

Optimization of MIMO Systems Capacity Using Large Random Matrix Methods

Directory of Open Access Journals (Sweden)

Philippe Loubaton

2012-11-01

Full Text Available This paper provides a comprehensive introduction of large random matrix methods for input covariance matrix optimization of mutual information of MIMO systems. It is first recalled informally how large system approximations of mutual information can be derived. Then, the optimization of the approximations is discussed, and important methodological points that are not necessarily covered by the existing literature are addressed, including the strict concavity of the approximation, the structure of the argument of its maximum, the accuracy of the large system approach with regard to the number of antennas, or the justification of iterative water-filling optimization algorithms. While the existing papers have developed methods adapted to a specific model, this contribution tries to provide a unified view of the large system approximation approach.

Random mask optimization for fast neutron coded aperture imaging

Energy Technology Data Exchange (ETDEWEB)

McMillan, Kyle [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Univ. of California, Los Angeles, CA (United States); Marleau, Peter [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Brubaker, Erik [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

2015-05-01

In coded aperture imaging, one of the most important factors determining the quality of reconstructed images is the choice of mask/aperture pattern. In many applications, uniformly redundant arrays (URAs) are widely accepted as the optimal mask pattern. Under ideal conditions, thin and highly opaque masks, URA patterns are mathematically constructed to provide artifact-free reconstruction however, the number of URAs for a chosen number of mask elements is limited and when highly penetrating particles such as fast neutrons and high-energy gamma-rays are being imaged, the optimum is seldom achieved. In this case more robust mask patterns that provide better reconstructed image quality may exist. Through the use of heuristic optimization methods and maximum likelihood expectation maximization (MLEM) image reconstruction, we show that for both point and extended neutron sources a random mask pattern can be optimized to provide better image quality than that of a URA.

Intermittency in 197Au fragmentation

International Nuclear Information System (INIS)

Dabrowska, A.; Holynski, R.; Olszewski, A.; Szarska, M.; Wilczynska, B.; Wolter, W.; Wosiek, B.; Cherry, M.L.; Deines-Jones, P.; Jones, W.V.; Sengupta, K.; Wefel, B.

1995-07-01

The concept of factorial moments was applied to an analysis of the dynamical fluctuations in the charge distributions of the fragments emitted from gold nuclei with energies 10.6 and < 1.0 GeV/n interacting with emulsion nuclei. Clear evidence for intermittent fluctuations has been found in an analysis using all the particles released from the gold projectile, with a stronger effect observed below 1 GeV/n than at 10.6 GeV/n. For the full data sets, however, the intermittency effect was found to be very sensitive to the singly charged particles, and neglecting these particles strongly reduces the intermittency signal. When the analysis is restricted to the multiply charged fragments, an intermittency effect is revealed only for multifragmentation events, although one that is enhanced as compared to the analysis of all, singly and multiply charged, particles. The properties of the anomalous fractal dimensions suggest a sequential decay mechanism, rather than the existence of possible critical behaviour in the process of nuclear fragmentation. The likely influence of the charge conservation effects and the finite size of decaying systems on the observed intermittency signals was pointed out. (author). 37 refs, 9 figs, 5 tabs

Effects of systematic phase errors on optimized quantum random-walk search algorithm

International Nuclear Information System (INIS)

Zhang Yu-Chao; Bao Wan-Su; Wang Xiang; Fu Xiang-Qun

2015-01-01

This study investigates the effects of systematic errors in phase inversions on the success rate and number of iterations in the optimized quantum random-walk search algorithm. Using the geometric description of this algorithm, a model of the algorithm with phase errors is established, and the relationship between the success rate of the algorithm, the database size, the number of iterations, and the phase error is determined. For a given database size, we obtain both the maximum success rate of the algorithm and the required number of iterations when phase errors are present in the algorithm. Analyses and numerical simulations show that the optimized quantum random-walk search algorithm is more robust against phase errors than Grover’s algorithm. (paper)

Optimal Energy Management for Microgrid with Stationary and Mobile Storage

Energy Technology Data Exchange (ETDEWEB)

Wang, Yubo; Wang, Bin; Zhang, Tianyang; Nazaripouya, Hamidreza; Chu, Chi-Cheng; Gadh, Rajit

2016-05-02

This paper studies energy management in a Microgrid (MG) with solar generation, Battery Energy Management System (BESS) and gridable (V2G) EVs. A two-stage stochastic optimization method is proposed to capture the intermittent solar generation and random EV user behaviors. It is subsequently formulated as a Mixed Integer Linear Programming (MILP) problem. To evalutate the proposed method, real solar generation, loads, BESS and EV data is used in Sample Average Approximation (SAA). Computational results show the correctness of the proposed method as well as steady and tightly bounded optimality gap. Comparisons demonstrate that the proposed stochastic method outperforms its deterministic counterpart at the expense of higher computational cost. It is also observed that moderate number of EVs helps to reduce the overall operational cost of the MG, which sheds light on future EV integration to the smart grid.

Intermittent control: a computational theory of human control.

Science.gov (United States)

Gawthrop, Peter; Loram, Ian; Lakie, Martin; Gollee, Henrik

2011-02-01

The paradigm of continuous control using internal models has advanced understanding of human motor control. However, this paradigm ignores some aspects of human control, including intermittent feedback, serial ballistic control, triggered responses and refractory periods. It is shown that event-driven intermittent control provides a framework to explain the behaviour of the human operator under a wider range of conditions than continuous control. Continuous control is included as a special case, but sampling, system matched hold, an intermittent predictor and an event trigger allow serial open-loop trajectories using intermittent feedback. The implementation here may be described as "continuous observation, intermittent action". Beyond explaining unimodal regulation distributions in common with continuous control, these features naturally explain refractoriness and bimodal stabilisation distributions observed in double stimulus tracking experiments and quiet standing, respectively. Moreover, given that human control systems contain significant time delays, a biological-cybernetic rationale favours intermittent over continuous control: intermittent predictive control is computationally less demanding than continuous predictive control. A standard continuous-time predictive control model of the human operator is used as the underlying design method for an event-driven intermittent controller. It is shown that when event thresholds are small and sampling is regular, the intermittent controller can masquerade as the underlying continuous-time controller and thus, under these conditions, the continuous-time and intermittent controller cannot be distinguished. This explains why the intermittent control hypothesis is consistent with the continuous control hypothesis for certain experimental conditions.

Optimization, ex vivo permeation, and stability study of lipid nanocarrier loaded gelatin capsules for treatment of intermittent claudication

Directory of Open Access Journals (Sweden)

Sallam MA

2015-07-01

Full Text Available Marwa Ahmed Sallam,1 María Teresa Marín Boscá21Department of Industrial Pharmacy, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt; 2Department of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, Granada University, Granada, Spain Abstract: In this study, an optimized nanodispersible oral dosage form (containing a lactate ester was developed for cilostazol (CZL. CZL is a phosphodiesterase inhibitor used for intermittent claudication. We aimed to improve the dissolution rate and absorption of CZL giving it a better chance of oral bioavailability, and to evaluate its stability on storage. Suitable compositions of nanoemulsion preconcentrate formulations were screened via solubility and compatibility tests. Response surface methodology and a desirability approach were applied to optimize preconcentrates containing minimum amount of surfactant mixture, maximum amount of lipid, and possessing the smallest globule size, with the highest emulsification and dissolution rates and minimum risk of drug precipitation. As part of the optimization process, the main effect, interaction effects and quadratic effects of amounts of lipid, and surfactant/co-surfactant ratio on % transmittance, globule size, emulsification time, drug precipitation, and drug release were investigated. The optimized formulation consisting of 28.9% butyl lactate, 28.9% Capryol®, 27.82% Solubilisant Gamma® 2429, and 14.18% Transcutol® possessing a globule size of 60 nm was mixed with Aerosil® 200. This gave uniform free flowing granules, which were characterized for surface and powder properties. The self-nanoemulsifying granules (SNEGs filled into hard gelatin capsules showed two- and threefold increase in CZL released compared with conventional tablet and pure drug, respectively. The amount of drug permeated using non-everted sac technique from the SNEGs was twofold higher than that permeated from the tablet suspension. The shelf life was 526 days at

Optimizing Linear Functions with Randomized Search Heuristics - The Robustness of Mutation

DEFF Research Database (Denmark)

Witt, Carsten

2012-01-01

The analysis of randomized search heuristics on classes of functions is fundamental for the understanding of the underlying stochastic process and the development of suitable proof techniques. Recently, remarkable progress has been made in bounding the expected optimization time of the simple (1...

Community-Based Promotional Campaign to Improve Uptake of Intermittent Preventive Antimalarial Treatment in Pregnancy in Burkina Faso

NARCIS (Netherlands)

Gies, Sabine; Coulibaly, Sheick O.; Ky, Clotilde; Ouattara, Florence T.; Brabin, Bernard J.; d'Alessandro, Umberto

2009-01-01

Malaria preventive strategies in pregnancy were assessed in a health center randomized trial comparing intermittent preventive treatment with sulfadoxine-pyrimethamine (IPTp-SP) with and without community based promotional activities in rural Burkina Faso. The study involved 2,240 secundigravidae

A stochastic space-time model for intermittent precipitation occurrences

KAUST Repository

Sun, Ying; Stein, Michael L.

2016-01-01

Modeling a precipitation field is challenging due to its intermittent and highly scale-dependent nature. Motivated by the features of high-frequency precipitation data from a network of rain gauges, we propose a threshold space-time t random field (tRF) model for 15-minute precipitation occurrences. This model is constructed through a space-time Gaussian random field (GRF) with random scaling varying along time or space and time. It can be viewed as a generalization of the purely spatial tRF, and has a hierarchical representation that allows for Bayesian interpretation. Developing appropriate tools for evaluating precipitation models is a crucial part of the model-building process, and we focus on evaluating whether models can produce the observed conditional dry and rain probabilities given that some set of neighboring sites all have rain or all have no rain. These conditional probabilities show that the proposed space-time model has noticeable improvements in some characteristics of joint rainfall occurrences for the data we have considered.

A stochastic space-time model for intermittent precipitation occurrences

KAUST Repository

Sun, Ying

2016-01-28

Modeling a precipitation field is challenging due to its intermittent and highly scale-dependent nature. Motivated by the features of high-frequency precipitation data from a network of rain gauges, we propose a threshold space-time t random field (tRF) model for 15-minute precipitation occurrences. This model is constructed through a space-time Gaussian random field (GRF) with random scaling varying along time or space and time. It can be viewed as a generalization of the purely spatial tRF, and has a hierarchical representation that allows for Bayesian interpretation. Developing appropriate tools for evaluating precipitation models is a crucial part of the model-building process, and we focus on evaluating whether models can produce the observed conditional dry and rain probabilities given that some set of neighboring sites all have rain or all have no rain. These conditional probabilities show that the proposed space-time model has noticeable improvements in some characteristics of joint rainfall occurrences for the data we have considered.

Solving the wind farm layout optimization problem using random search algorithm

DEFF Research Database (Denmark)

Feng, Ju; Shen, Wen Zhong

2015-01-01

, in which better results than the genetic algorithm (GA) and the old version of the RS algorithm are obtained. Second it is applied to the Horns Rev 1 WF, and the optimized layouts obtain a higher power production than its original layout, both for the real scenario and for two constructed scenarios......Wind farm (WF) layout optimization is to find the optimal positions of wind turbines (WTs) inside a WF, so as to maximize and/or minimize a single objective or multiple objectives, while satisfying certain constraints. In this work, a random search (RS) algorithm based on continuous formulation....... In this application, it is also found that in order to get consistent and reliable optimization results, up to 360 or more sectors for wind direction have to be used. Finally, considering the inevitable inter-annual variations in the wind conditions, the robustness of the optimized layouts against wind condition...

Intermittency in Complex Flows

Science.gov (United States)

Ben Mahjoub, Otman; Redondo, Jose M.

2017-04-01

Experimental results of the complex turbulent wake of a cilinder in 2D [1] and 3D flows [2] were used to investigate the scaling of structure functions, similar research was also performed on wave propagation and breaking in the Ocean [3], in the the stratified Atmosphere (ABL) [4] and in a 100large flume (UPC) for both regular and irregular waves, where long time series of waves propagating and generating breaking turbulence velocity rms and higher order measurements were taken in depth. [3,5] by means of a velocimeter SONTEK3-D. The probability distribution functions of the velocity differences and their non Gaussian distribution related to the energy spectrum indicate that irregularity is an important source of turbulence. From Kolmogorov's K41 and K61 intermittency correction: the p th-order longitudinal velocity structure function δul at scale l in the inertial range of three-dimensional fully developed turbulence is related by ⟨δup⟩ = ⟨(u(x+ l)- u(x))p⟩ ˜ ɛp0/3lp/3 l where ⟨...⟩ represents the spatial average over flow domain, with ɛ0 the mean energy dissipation per unit mass and l is the separation distance. The importance of the random nature of the energy dissipation led to the K62 theory of intermittency, but locality and non-homogeneity are key issues. p p/3 p/3 ξd ⟨δul⟩ ˜ ⟨ɛl ⟩l ˜ l and ξp = p 3 + τp/3 , where now ɛl is a fractal energy dissipation at scale l, τp/3 is the scaling of and ξp is the scaling exponent of the velocity structure function of order p. Both in K41 and K62, the structure functions of third order related to skewness is ξ3 = 1. But this is not true either. We show that scaling exponents ξp do deviate from early studies that only investigated homogeneous turbulence, where a large inertial range dominates. The use of multi-fractal analysis and improvements on Structure function calculations on standard Enhanced mixing is an essential property of turbulence and efforts to alter and to control

Intermittency '93

International Nuclear Information System (INIS)

Bialas, A.

1993-01-01

The existing data definitely indicate the existence of intermittency, i.e. of self similar structures in the systems of particles created in high-energy collisions. The effect seems universal: it was found in most of the processes investigated and its measures parameters depend only weakly (if at all) on the process in question. Strong HBT effect was found, suggesting that intermittency is related to space-time structure of the pion source rather than to detailed momentum structure of the production amplitudes. There are indications that this space time structure may be fractal, but more data is needed to establish this. The theoretical explanation remains obscure: it seems that both parton cascade and hadronization play an important role. Their interrelation, however, remains a mystery. 5 figs., 19 refs

Flume experiments on intermittency and zero-crossing properties of canopy turbulence

Science.gov (United States)

Poggi, Davide; Katul, Gabriel

2009-06-01

How the presence of a canopy alters the clustering and the fine scale intermittency exponents and any possible connections between them remains a vexing research problem in canopy turbulence. To begin progress on this problem, detailed flume experiments in which the longitudinal and vertical velocity time series were acquired using laser Doppler anemometry within and above a uniform canopy composed of densely arrayed rods. The time series analysis made use of the telegraphic approximation (TA) and phase-randomization (PR) methods. The TA preserved the so-called zero-crossing properties in the original turbulent velocity time series but eliminated amplitude variations, while the PR generated surrogate data that preserved the spectral scaling laws in the velocity series but randomized the acceleration statistics. Based on these experiments, it was shown that the variations in the dissipation intermittency exponents were well described by the Taylor microscale Reynolds number (Reλ) within and above the canopy. In terms of clustering, quantified here using the variance in zero-crossing density across scales, two scaling regimes emerged. For spatial scales much larger than the canopy height hc, representing the canonical scale of the vortices dominating the flow, no significant clustering was detected. For spatial scales much smaller than hc, significant clustering was discernable and follows an extensive scaling law inside the canopy. Moreover, the canopy signatures on the clustering scaling laws were weak. When repeating these clustering measures on the PR data, the results were indistinguishable from the original series. Hence, clustering exponents derived from variances in zero-crossing density across scales primarily depended on the velocity correlation function and not on the distributional properties of the acceleration. In terms of the connection between dissipation intermittency and clustering exponents, there was no significant relationship. While the former

Tangent map intermittency as an approximate analysis of intermittency in a high dimensional fully stochastic dynamical system: The Tangled Nature model.

Science.gov (United States)

Diaz-Ruelas, Alvaro; Jeldtoft Jensen, Henrik; Piovani, Duccio; Robledo, Alberto

2016-12-01

It is well known that low-dimensional nonlinear deterministic maps close to a tangent bifurcation exhibit intermittency and this circumstance has been exploited, e.g., by Procaccia and Schuster [Phys. Rev. A 28, 1210 (1983)], to develop a general theory of 1/f spectra. This suggests it is interesting to study the extent to which the behavior of a high-dimensional stochastic system can be described by such tangent maps. The Tangled Nature (TaNa) Model of evolutionary ecology is an ideal candidate for such a study, a significant model as it is capable of reproducing a broad range of the phenomenology of macroevolution and ecosystems. The TaNa model exhibits strong intermittency reminiscent of punctuated equilibrium and, like the fossil record of mass extinction, the intermittency in the model is found to be non-stationary, a feature typical of many complex systems. We derive a mean-field version for the evolution of the likelihood function controlling the reproduction of species and find a local map close to tangency. This mean-field map, by our own local approximation, is able to describe qualitatively only one episode of the intermittent dynamics of the full TaNa model. To complement this result, we construct a complete nonlinear dynamical system model consisting of successive tangent bifurcations that generates time evolution patterns resembling those of the full TaNa model in macroscopic scales. The switch from one tangent bifurcation to the next in the sequences produced in this model is stochastic in nature, based on criteria obtained from the local mean-field approximation, and capable of imitating the changing set of types of species and total population in the TaNa model. The model combines full deterministic dynamics with instantaneous parameter random jumps at stochastically drawn times. In spite of the limitations of our approach, which entails a drastic collapse of degrees of freedom, the description of a high-dimensional model system in terms of a low

Modeling and Compensation of Random Drift of MEMS Gyroscopes Based on Least Squares Support Vector Machine Optimized by Chaotic Particle Swarm Optimization.

Science.gov (United States)

Xing, Haifeng; Hou, Bo; Lin, Zhihui; Guo, Meifeng

2017-10-13

MEMS (Micro Electro Mechanical System) gyroscopes have been widely applied to various fields, but MEMS gyroscope random drift has nonlinear and non-stationary characteristics. It has attracted much attention to model and compensate the random drift because it can improve the precision of inertial devices. This paper has proposed to use wavelet filtering to reduce noise in the original data of MEMS gyroscopes, then reconstruct the random drift data with PSR (phase space reconstruction), and establish the model for the reconstructed data by LSSVM (least squares support vector machine), of which the parameters were optimized using CPSO (chaotic particle swarm optimization). Comparing the effect of modeling the MEMS gyroscope random drift with BP-ANN (back propagation artificial neural network) and the proposed method, the results showed that the latter had a better prediction accuracy. Using the compensation of three groups of MEMS gyroscope random drift data, the standard deviation of three groups of experimental data dropped from 0.00354°/s, 0.00412°/s, and 0.00328°/s to 0.00065°/s, 0.00072°/s and 0.00061°/s, respectively, which demonstrated that the proposed method can reduce the influence of MEMS gyroscope random drift and verified the effectiveness of this method for modeling MEMS gyroscope random drift.

A Fast Reactive Power Optimization in Distribution Network Based on Large Random Matrix Theory and Data Analysis

Directory of Open Access Journals (Sweden)

Wanxing Sheng

2016-05-01

Full Text Available In this paper, a reactive power optimization method based on historical data is investigated to solve the dynamic reactive power optimization problem in distribution network. In order to reflect the variation of loads, network loads are represented in a form of random matrix. Load similarity (LS is defined to measure the degree of similarity between the loads in different days and the calculation method of the load similarity of load random matrix (LRM is presented. By calculating the load similarity between the forecasting random matrix and the random matrix of historical load, the historical reactive power optimization dispatching scheme that most matches the forecasting load can be found for reactive power control usage. The differences of daily load curves between working days and weekends in different seasons are considered in the proposed method. The proposed method is tested on a standard 14 nodes distribution network with three different types of load. The computational result demonstrates that the proposed method for reactive power optimization is fast, feasible and effective in distribution network.

Random walk in genome space: A key ingredient of intermittent dynamics of community assembly on evolutionary time scales

KAUST Repository

Murase, Yohsuke

2010-06-01

Community assembly is studied using individual-based multispecies models. The models have stochastic population dynamics with mutation, migration, and extinction of species. Mutants appear as a result of mutation of the resident species, while migrants have no correlation with the resident species. It is found that the dynamics of community assembly with mutations are quite different from the case with migrations. In contrast to mutation models, which show intermittent dynamics of quasi-steady states interrupted by sudden reorganizations of the community, migration models show smooth and gradual renewal of the community. As a consequence, instead of the 1/f diversity fluctuations found for the mutation models, 1/f2, random-walk like fluctuations are observed for the migration models. In addition, a characteristic species-lifetime distribution is found: a power law that is cut off by a "skewed" distribution in the long-lifetime regime. The latter has a longer tail than a simple exponential function, which indicates an age-dependent species-mortality function. Since this characteristic profile has been observed, both in fossil data and in several other mathematical models, we conclude that it is a universal feature of macroevolution. © 2010 Elsevier Ltd.

Random walk in genome space: A key ingredient of intermittent dynamics of community assembly on evolutionary time scales

KAUST Repository

Murase, Yohsuke; Shimada, Takashi; Ito, Nobuyasu; Rikvold, Per Arne

2010-01-01

Community assembly is studied using individual-based multispecies models. The models have stochastic population dynamics with mutation, migration, and extinction of species. Mutants appear as a result of mutation of the resident species, while migrants have no correlation with the resident species. It is found that the dynamics of community assembly with mutations are quite different from the case with migrations. In contrast to mutation models, which show intermittent dynamics of quasi-steady states interrupted by sudden reorganizations of the community, migration models show smooth and gradual renewal of the community. As a consequence, instead of the 1/f diversity fluctuations found for the mutation models, 1/f2, random-walk like fluctuations are observed for the migration models. In addition, a characteristic species-lifetime distribution is found: a power law that is cut off by a "skewed" distribution in the long-lifetime regime. The latter has a longer tail than a simple exponential function, which indicates an age-dependent species-mortality function. Since this characteristic profile has been observed, both in fossil data and in several other mathematical models, we conclude that it is a universal feature of macroevolution. © 2010 Elsevier Ltd.

Use of Monte Carlo Simulations to Determine Optimal Carbapenem Dosing in Critically Ill Patients Receiving Prolonged Intermittent Renal Replacement Therapy.

Science.gov (United States)

Lewis, Susan J; Kays, Michael B; Mueller, Bruce A

2016-10-01

Pharmacokinetic/pharmacodynamic analyses with Monte Carlo simulations (MCSs) can be used to integrate prior information on model parameters into a new renal replacement therapy (RRT) to develop optimal drug dosing when pharmacokinetic trials are not feasible. This study used MCSs to determine initial doripenem, imipenem, meropenem, and ertapenem dosing regimens for critically ill patients receiving prolonged intermittent RRT (PIRRT). Published body weights and pharmacokinetic parameter estimates (nonrenal clearance, free fraction, volume of distribution, extraction coefficients) with variability were used to develop a pharmacokinetic model. MCS of 5000 patients evaluated multiple regimens in 4 different PIRRT effluent/duration combinations (4 L/h × 10 hours or 5 L/h × 8 hours in hemodialysis or hemofiltration) occurring at the beginning or 14-16 hours after drug infusion. The probability of target attainment (PTA) was calculated using ≥40% free serum concentrations above 4 times the minimum inhibitory concentration (MIC) for the first 48 hours. Optimal doses were defined as the smallest daily dose achieving ≥90% PTA in all PIRRT combinations. At the MIC of 2 mg/L for Pseudomonas aeruginosa, optimal doses were doripenem 750 mg every 8 hours, imipenem 1 g every 8 hours or 750 mg every 6 hours, and meropenem 1 g every 12 hours or 1 g pre- and post-PIRRT. Ertapenem 500 mg followed by 500 mg post-PIRRT was optimal at the MIC of 1 mg/L for Streptococcus pneumoniae. Incorporating data from critically ill patients receiving RRT into MCS resulted in markedly different carbapenem dosing regimens in PIRRT from those recommended for conventional RRTs because of the unique drug clearance characteristics of PIRRT. These results warrant clinical validation. © 2016, The American College of Clinical Pharmacology.

Understanding Adherence to Daily and Intermittent Regimens of Oral HIV Pre-exposure Prophylaxis Among Men Who Have Sex with Men in Kenya.

Science.gov (United States)

Mugo, Peter Mwangi; Sanders, Eduard J; Mutua, Gaudensia; van der Elst, Elisabeth; Anzala, Omu; Barin, Burc; Bangsberg, David R; Priddy, Frances H; Haberer, Jessica E

2015-05-01

A qualitative assessment of Kenyan men who have sex with men taking daily and intermittent oral HIV pre-exposure prophylaxis (PrEP) found stigma, sex work, mobility, and alcohol impacted adherence. We analyzed quantitative data from the same cohort to explore different definitions of intermittent adherence. Volunteers were randomized to daily emtricitabine/tenofovir or placebo, or intermittent (prescription: Mondays/Fridays/after sex, maximum 1 dose/day) emtricitabine/tenofovir or placebo (2:1:2:1), and followed for 4 months. By electronic monitoring, median adherence for daily dosing was 80 %. Median adherence for intermittent dosing was 71 % per a "relaxed" definition (accounting for off-prescription dosing) and 40 % per a "strict" definition (limited to the prescription). Factors associated with lower adherence included travel, transactional sex, and longer follow-up; higher adherence was associated with daily dosing and an income. The definition of intermittent dosing strongly affects interpretation of adherence. These findings suggest interventions should address challenges of mobility, sex work, and long-term PrEP.

Statistical distributions of optimal global alignment scores of random protein sequences

Directory of Open Access Journals (Sweden)

Tang Jiaowei

2005-10-01

Full Text Available Abstract Background The inference of homology from statistically significant sequence similarity is a central issue in sequence alignments. So far the statistical distribution function underlying the optimal global alignments has not been completely determined. Results In this study, random and real but unrelated sequences prepared in six different ways were selected as reference datasets to obtain their respective statistical distributions of global alignment scores. All alignments were carried out with the Needleman-Wunsch algorithm and optimal scores were fitted to the Gumbel, normal and gamma distributions respectively. The three-parameter gamma distribution performs the best as the theoretical distribution function of global alignment scores, as it agrees perfectly well with the distribution of alignment scores. The normal distribution also agrees well with the score distribution frequencies when the shape parameter of the gamma distribution is sufficiently large, for this is the scenario when the normal distribution can be viewed as an approximation of the gamma distribution. Conclusion We have shown that the optimal global alignment scores of random protein sequences fit the three-parameter gamma distribution function. This would be useful for the inference of homology between sequences whose relationship is unknown, through the evaluation of gamma distribution significance between sequences.

Pressure Autoregulation Measurement Techniques in Adult Traumatic Brain Injury, Part I: A Scoping Review of Intermittent/Semi-Intermittent Methods.

Science.gov (United States)

Zeiler, Frederick A; Donnelly, Joseph; Calviello, Leanne; Menon, David K; Smielewski, Peter; Czosnyka, Marek

2017-12-01

The purpose of this study was to perform a systematic, scoping review of commonly described intermittent/semi-intermittent autoregulation measurement techniques in adult traumatic brain injury (TBI). Nine separate systematic reviews were conducted for each intermittent technique: computed tomographic perfusion (CTP)/Xenon-CT (Xe-CT), positron emission tomography (PET), magnetic resonance imaging (MRI), arteriovenous difference in oxygen (AVDO 2 ) technique, thigh cuff deflation technique (TCDT), transient hyperemic response test (THRT), orthostatic hypotension test (OHT), mean flow index (Mx), and transfer function autoregulation index (TF-ARI). MEDLINE ® , BIOSIS, EMBASE, Global Health, Scopus, Cochrane Library (inception to December 2016), and reference lists of relevant articles were searched. A two tier filter of references was conducted. The total number of articles utilizing each of the nine searched techniques for intermittent/semi-intermittent autoregulation techniques in adult TBI were: CTP/Xe-CT (10), PET (6), MRI (0), AVDO 2 (10), ARI-based TCDT (9), THRT (6), OHT (3), Mx (17), and TF-ARI (6). The premise behind all of the intermittent techniques is manipulation of systemic blood pressure/blood volume via either chemical (such as vasopressors) or mechanical (such as thigh cuffs or carotid compression) means. Exceptionally, Mx and TF-ARI are based on spontaneous fluctuations of cerebral perfusion pressure (CPP) or mean arterial pressure (MAP). The method for assessing the cerebral circulation during these manipulations varies, with both imaging-based techniques and TCD utilized. Despite the limited literature for intermittent/semi-intermittent techniques in adult TBI (minus Mx), it is important to acknowledge the availability of such tests. They have provided fundamental insight into human autoregulatory capacity, leading to the development of continuous and more commonly applied techniques in the intensive care unit (ICU). Numerous methods of

Prolonged Intermittent Renal Replacement Therapy.

Science.gov (United States)

Edrees, Fahad; Li, Tingting; Vijayan, Anitha

2016-05-01

Prolonged intermittent renal replacement therapy (PIRRT) is becoming an increasingly popular alternative to continuous renal replacement therapy in critically ill patients with acute kidney injury. There are significant practice variations in the provision of PIRRT across institutions, with respect to prescription, technology, and delivery of therapy. Clinical trials have generally demonstrated that PIRRT is non-inferior to continuous renal replacement therapy regarding patient outcomes. PIRRT offers cost-effective renal replacement therapy along with other advantages such as early patient mobilization and decreased nursing time. However, due to lack of standardization of the procedure, PIRRT still poses significant challenges, especially pertaining to appropriate drug dosing. Future guidelines and clinical trials should work toward developing consensus definitions for PIRRT and ensure optimal delivery of therapy. Copyright © 2016 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Optimal state estimation over communication channels with random delays

KAUST Repository

Mahmoud, Magdi S.; Liu, Bo

2013-01-01

This paper is concerned with the optimal estimation of linear systems over unreliable communication channels with random delays. The measurements are delivered without time stamp, and the probabilities of time delays are assumed to be known. Since the estimation is time-driven, the actual time delays are converted into virtual time delays among the formulation. The receiver of estimation node stores the sum of arrived measurements between two adjacent processing time instants and also counts the number of arrived measurements. The original linear system is modeled as an extended system with uncertain observation to capture the feature of communication, then the optimal estimation algorithm of systems with uncertain observations is proposed. Additionally, a numerical simulation is presented to show the performance of this work. © 2013 The Franklin Institute.

Optimal state estimation over communication channels with random delays

KAUST Repository

Mahmoud, Magdi S.

2013-04-01

This paper is concerned with the optimal estimation of linear systems over unreliable communication channels with random delays. The measurements are delivered without time stamp, and the probabilities of time delays are assumed to be known. Since the estimation is time-driven, the actual time delays are converted into virtual time delays among the formulation. The receiver of estimation node stores the sum of arrived measurements between two adjacent processing time instants and also counts the number of arrived measurements. The original linear system is modeled as an extended system with uncertain observation to capture the feature of communication, then the optimal estimation algorithm of systems with uncertain observations is proposed. Additionally, a numerical simulation is presented to show the performance of this work. © 2013 The Franklin Institute.

Intermittent fasting interventions for treatment of overweight and obesity in adults: a systematic review and meta-analysis.

Science.gov (United States)

Harris, Leanne; Hamilton, Sharon; Azevedo, Liane B; Olajide, Joan; De Brún, Caroline; Waller, Gillian; Whittaker, Vicki; Sharp, Tracey; Lean, Mike; Hankey, Catherine; Ells, Louisa

2018-02-01

To examine the effectiveness of intermittent energy restriction in the treatment for overweight and obesity in adults, when compared to usual care treatment or no treatment. Intermittent energy restriction encompasses dietary approaches including intermittent fasting, alternate day fasting, and fasting for two days per week. Despite the recent popularity of intermittent energy restriction and associated weight loss claims, the supporting evidence base is limited. This review included overweight or obese (BMI ≥25 kg/m) adults (≥18 years). Intermittent energy restriction was defined as consumption of ≤800 kcal on at least one day, but no more than six days per week. Intermittent energy restriction interventions were compared to no treatment (ad libitum diet) or usual care (continuous energy restriction ∼25% of recommended energy intake). Included interventions had a minimum duration of 12 weeks from baseline to post outcome measurements. The types of studies included were randomized and pseudo-randomized controlled trials. The primary outcome of this review was change in body weight. Secondary outcomes included: i) anthropometric outcomes (change in BMI, waist circumference, fat mass, fat free mass); ii) cardio-metabolic outcomes (change in blood glucose and insulin, lipoprotein profiles and blood pressure); and iii) lifestyle outcomes: diet, physical activity, quality of life and adverse events. A systematic search was conducted from database inception to November 2015. The following electronic databases were searched: MEDLINE, Embase, CINAHL, Cochrane Library, ClinicalTrials.gov, ISRCTN registry, and anzctr.org.au for English language published studies, protocols and trials. Two independent reviewers evaluated the methodological quality of included studies using the standardized critical appraisal instruments from the Joanna Briggs Institute. Data were extracted from papers included in the review by two independent reviewers using the standardized data

Intermittency in {sup 197}Au fragmentation

Energy Technology Data Exchange (ETDEWEB)

Dabrowska, A; Holynski, R; Olszewski, A; Szarska, M; Wilczynska, B; Wolter, W; Wosiek, B [Institute of Nuclear Physics, Cracow (Poland); Cherry, M L; Deines-Jones, P; Jones, W V; Sengupta, K; Wefel, B [Louisiana State Univ., Baton Rouge, LA (United States). Dept. of Physics and Astronomy; Waddington, C J [Minnesota Univ., Minneapolis, MN (United States). School of Physics and Astronomy; Pozharova, E A; Skorodko, T Yu [Inst. of Theoretical and Experimental Physics, Moscow (Russian Federation); KLMM Collaboration

1995-07-01

The concept of factorial moments was applied to an analysis of the dynamical fluctuations in the charge distributions of the fragments emitted from gold nuclei with energies 10.6 and < 1.0 GeV/n interacting with emulsion nuclei. Clear evidence for intermittent fluctuations has been found in an analysis using all the particles released from the gold projectile, with a stronger effect observed below 1 GeV/n than at 10.6 GeV/n. For the full data sets, however, the intermittency effect was found to be very sensitive to the singly charged particles, and neglecting these particles strongly reduces the intermittency signal. When the analysis is restricted to the multiply charged fragments, an intermittency effect is revealed only for multifragmentation events, although one that is enhanced as compared to the analysis of all, singly and multiply charged, particles. The properties of the anomalous fractal dimensions suggest a sequential decay mechanism, rather than the existence of possible critical behaviour in the process of nuclear fragmentation. The likely influence of the charge conservation effects and the finite size of decaying systems on the observed intermittency signals was pointed out. (author). 37 refs, 9 figs, 5 tabs.

Thromboprophylaxis using combined intermittent pneumatic compression and pharmacologic prophylaxis versus pharmacologic prophylaxis alone in critically ill patients: study protocol for a randomized controlled trial.

Science.gov (United States)

Arabi, Yaseen M; Alsolamy, Sami; Al-Dawood, Abdulaziz; Al-Omari, Awad; Al-Hameed, Fahad; Burns, Karen E A; Almaani, Mohammed; Lababidi, Hani; Al Bshabshe, Ali; Mehta, Sangeeta; Al-Aithan, Abdulsalam M; Mandourah, Yasser; Almekhlafi, Ghaleb; Finfer, Simon; Abdukahil, Sheryl Ann I; Afesh, Lara Y; Dbsawy, Maamoun; Sadat, Musharaf

2016-08-03

Venous thromboembolism (VTE) remains a common problem in critically ill patients. Pharmacologic prophylaxis is currently the standard of care based on high-level evidence from randomized controlled trials. However, limited evidence exists regarding the effectiveness of intermittent pneumatic compression (IPC) devices. The Pneumatic compREssion for preventing VENous Thromboembolism (PREVENT trial) aims to determine whether the adjunct use of IPC with pharmacologic prophylaxis compared to pharmacologic prophylaxis alone in critically ill patients reduces the risk of VTE. The PREVENT trial is a multicenter randomized controlled trial, which will recruit 2000 critically ill patients from over 20 hospitals in three countries. The primary outcome is the incidence of proximal lower extremity deep vein thrombosis (DVT) within 28 days after randomization. Radiologists interpreting the scans are blinded to intervention allocation, whereas the patients and caregivers are unblinded. The trial has 80 % power to detect a 3 % absolute risk reduction in proximal DVT from 7 to 4 %. The first patient was enrolled in July 2014. As of May 2015, a total of 650 patients have been enrolled from 13 centers in Saudi Arabia, Canada and Australia. The first interim analysis is anticipated in July 2016. We expect to complete recruitment by 2018. Clinicaltrials.gov: NCT02040103 (registered on 3 November 2013). Current controlled trials: ISRCTN44653506 (registered on 30 October 2013).

Intelligent Fault Diagnosis of HVCB with Feature Space Optimization-Based Random Forest.

Science.gov (United States)

Ma, Suliang; Chen, Mingxuan; Wu, Jianwen; Wang, Yuhao; Jia, Bowen; Jiang, Yuan

2018-04-16

Mechanical faults of high-voltage circuit breakers (HVCBs) always happen over long-term operation, so extracting the fault features and identifying the fault type have become a key issue for ensuring the security and reliability of power supply. Based on wavelet packet decomposition technology and random forest algorithm, an effective identification system was developed in this paper. First, compared with the incomplete description of Shannon entropy, the wavelet packet time-frequency energy rate (WTFER) was adopted as the input vector for the classifier model in the feature selection procedure. Then, a random forest classifier was used to diagnose the HVCB fault, assess the importance of the feature variable and optimize the feature space. Finally, the approach was verified based on actual HVCB vibration signals by considering six typical fault classes. The comparative experiment results show that the classification accuracy of the proposed method with the origin feature space reached 93.33% and reached up to 95.56% with optimized input feature vector of classifier. This indicates that feature optimization procedure is successful, and the proposed diagnosis algorithm has higher efficiency and robustness than traditional methods.

Multi-point observations of intermittency in the cusp regions

Directory of Open Access Journals (Sweden)

M. M. Echim

2007-08-01

Full Text Available In this paper we investigate the statistical properties of magnetic field fluctuations measured by the four Cluster spacecraft in the cusp and close to the interface with the magnetospheric lobes, magnetopause and magnetosheath. At lower altitudes along the outbound orbit of 26 February 2001, the magnetic field fluctuations recorded by all four spacecraft are random and their Probability Distribution Functions (PDFs are Gaussian at all scales. The flatness parameter, F – related to the kurtosis of the time series, is equal to 3. At higher altitudes, in the cusp and its vicinity, closer to the interface with the magnetopause and magnetosheath, the PDFs from all Cluster satellites are non-Gaussian and show a clear intermittent behavior at scales smaller than τ_G≈ 61 s (or 170 km. The flatness parameter increases to values greater than 3 for scales smaller than τ_G. A Haar wavelet transform enables the identification of the "events" that produce sudden variations of the magnetic field and of the scales that have most of the power. The LIM parameter (i.e. normalized wavelet power indicates that events for scales below 65 s are non-uniformly distributed throughout the cusp passage. PDFs, flatness and wavelet analysis show that at coarse-grained scales larger than τ_G the intermittency is absent in the cusp. Fluctuations of the magnetic energy observed during the same orbit in the magnetosheath show PDFs that tend toward a Gaussian at scales smaller than τ_G found in the cusp. The flatness analysis confirms the decreasing of τ_G from cusp to magnetosheath. Our analysis reveals the turbulent cusp as a transition region from a non-intermittent turbulent state inside the magnetosphere to an intermittent turbulent state in the magnetosheath that has statistical properties resembling the solar wind turbulence. The observed turbulent fluctuations in the cusp suggests a phenomenon of nonlinear

The organ specificity in pathological damage of chronic intermittent hypoxia: an experimental study on rat with high-fat diet.

Science.gov (United States)

Wang, Hui; Tian, Jian-li; Feng, Shu-zhi; Sun, Ning; Chen, Bao-yuan; Zhang, Yun

2013-09-01

It is known today that sleep apnea hypopnea syndrome and its characteristic chronic intermittent hypoxia can cause damages to multiple organs, including the cardiovascular system, urinary system, and liver. It is still unclear, however, whether the damage caused by sleep apnea hypopnea syndrome and the severity of the damage are organ-specific. This research observed the pathological effects of chronic intermittent hypoxia on rat's thoracic aorta, myocardium, liver, and kidney, under the condition of lipid metabolism disturbance, through establishing the rat model of chronic intermittent hypoxia with high-fat diet by imitating the features of human sleep apnea hypopnea syndrome. In this model, 24 male Wistar rats were randomly divided into three groups: a control group fed by regular diet, a high-fat group fed by high-fat diet, and a high-fat plus intermittent hypoxia group fed by high-fat diet and treated with intermittent hypoxia 7 h a day. At the end of the ninth week, the pathological changes of rat's organs, including the thoracic aorta, myocardium, liver, and kidney are observed (under both optical microscopy and transmission electron microscopy). As the result of the experiment shows, while there was no abnormal effect observed on any organs of the control group, slight pathological changes were found in the organs of the high-fat group. For the high-fat plus intermittent hypoxia group, however, remarkably severer damages were found on all the organs. It also showed that the severity of the damage varies by organ in the high-fat plus intermittent hypoxia group, with the thoracic aorta being the worst, followed by the liver and myocardium, and the kidney being the slightest. Chronic intermittent hypoxia can lead to multiple-organ damage to rat with high-fat diet. Different organs appear to have different sensitivity to chronic intermittent hypoxia.

Optimal Lot Sizing with Scrap and Random Breakdown Occurring in Backorder Replenishing Period

OpenAIRE

Ting, Chia-Kuan; Chiu, Yuan-Shyi; Chan, Chu-Chai

2011-01-01

This paper is concerned with determination of optimal lot size for an economic production quantity model with scrap and random breakdown occurring in backorder replenishing period. In most real-life manufacturing systems, generation of defective items and random breakdown of production equipment are inevitable. To deal with the stochastic machine failures, production planners practically calculate the mean time between failures (MTBF) and establish the robust plan accordingly, in terms of opt...

Analysis in nuclear power accident emergency based on random network and particle swarm optimization

International Nuclear Information System (INIS)

Gong Dichen; Fang Fang; Ding Weicheng; Chen Zhi

2014-01-01

The GERT random network model of nuclear power accident emergency was built in this paper, and the intelligent computation was combined with the random network based on the analysis of Fukushima nuclear accident in Japan. The emergency process was divided into the series link and parallel link, and the parallel link was the part of series link. The overall allocation of resources was firstly optimized, and then the parallel link was analyzed. The effect of the resources for emergency used in different links was analyzed, and it was put forward that the corresponding particle velocity vector was limited under the condition of limited emergency resources. The resource-constrained particle swarm optimization was obtained by using velocity projection matrix to correct the motion of particles. The optimized allocation of resources in emergency process was obtained and the time consumption of nuclear power accident emergency was reduced. (authors)

On the efficiency of a randomized mirror descent algorithm in online optimization problems

Science.gov (United States)

Gasnikov, A. V.; Nesterov, Yu. E.; Spokoiny, V. G.

2015-04-01

A randomized online version of the mirror descent method is proposed. It differs from the existing versions by the randomization method. Randomization is performed at the stage of the projection of a subgradient of the function being optimized onto the unit simplex rather than at the stage of the computation of a subgradient, which is common practice. As a result, a componentwise subgradient descent with a randomly chosen component is obtained, which admits an online interpretation. This observation, for example, has made it possible to uniformly interpret results on weighting expert decisions and propose the most efficient method for searching for an equilibrium in a zero-sum two-person matrix game with sparse matrix.

A Novel Path Planning for Robots Based on Rapidly-Exploring Random Tree and Particle Swarm Optimizer Algorithm

Directory of Open Access Journals (Sweden)

Zhou Feng

2013-09-01

Full Text Available A based on Rapidly-exploring Random Tree(RRT and Particle Swarm Optimizer (PSO for path planning of the robot is proposed.First the grid method is built to describe the working space of the mobile robot,then the Rapidly-exploring Random Tree algorithm is used to obtain the global navigation path,and the Particle Swarm Optimizer algorithm is adopted to get the better path.Computer experiment results demonstrate that this novel algorithm can plan an optimal path rapidly in a cluttered environment.The successful obstacle avoidance is achieved,and the model is robust and performs reliably.

Optimal random perturbations for stochastic approximation using a simultaneous perturbation gradient approximation

DEFF Research Database (Denmark)

Sadegh, Payman; Spall, J. C.

1998-01-01

simultaneous perturbation approximation to the gradient based on loss function measurements. SPSA is based on picking a simultaneous perturbation (random) vector in a Monte Carlo fashion as part of generating the approximation to the gradient. This paper derives the optimal distribution for the Monte Carlo...

Coordination of Heat Pumps, Electric Vehicles and AGC for Efficient LFC in a Smart Hybrid Power System via SCA-Based Optimized FOPID Controllers

Directory of Open Access Journals (Sweden)

Rahmat Khezri

2018-02-01

Full Text Available Due to the high price of fossil fuels, the increased carbon footprint in conventional generation units and the intermittent functionality of renewable units, alternative sources must contribute to the load frequency control (LFC of the power system. To tackle the challenge, dealing with controllable loads, the ongoing study aims at efficient LFC in smart hybrid power systems. To achieve this goal, heat pumps (HPs and electric vehicles (EVs are selected as the most effective controllable loads to contribute to the LFC issue. In this regard, the EVs can be controlled in a bidirectional manner as known charging and discharging states under a smart structure. In addition, regarding the HPs, the power consumption is controllable. As the main task, this paper proposes a fractional order proportional integral differential (FOPID controller for coordinated control of power consumption in HPs, the discharging state in EVs and automatic generation control (AGC. The parameters of the FOPID controllers are optimized simultaneously by the sine cosine algorithm (SCA, which is a new method for optimization problems. In the sequel, four scenarios, including step and random load changes, aggregated intermittent generated power from wind turbines, a random load change scenario and a sensitivity analysis scenario, are selected to demonstrate the efficiency of the proposed SCA-based FOPID controllers in a hybrid two-area power system.

Intermittent fasting protects against the deterioration of cognitive function, energy metabolism and dyslipidemia in Alzheimer's disease-induced estrogen deficient rats.

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Shin, Bae Kun; Kang, Suna; Kim, Da Sol; Park, Sunmin

2018-02-01

Intermittent fasting may be an effective intervention to protect against age-related metabolic disturbances, although it is still controversial. Here, we investigated the effect of intermittent fasting on the deterioration of the metabolism and cognitive functions in rats with estrogen deficiency and its mechanism was also explored. Ovariectomized rats were infused with β-amyloid (25-35; Alzheimer's disease) or β-amyloid (35-25, Non-Alzheimer's disease; normal cognitive function) into the hippocampus. Each group was randomly divided into two sub-groups: one with intermittent fasting and the other fed ad libitum: Alzheimer's disease-ad libitum, Alzheimer's disease-intermittent fasting, Non-Alzheimer's disease-ad libitum, and Non-Alzheimer's disease-intermittent fasting. Rats in the intermittent fasting groups had a restriction of food consumption to a 3-h period every day. Each group included 10 rats and all rats fed a high-fat diet for four weeks. Interestingly, Alzheimer's disease increased tail skin temperature more than Non-Alzheimer's disease and intermittent fasting prevented the increase. Alzheimer's disease reduced bone mineral density in the spine and femur compared to the Non-Alzheimer's disease, whereas bone mineral density in the hip and leg was reduced by intermittent fasting. Fat mass only in the abdomen was decreased by intermittent fasting. Intermittent fasting decreased food intake without changing energy expenditure. Alzheimer's disease increased glucose oxidation, whereas intermittent fasting elevated fat oxidation as a fuel source. Alzheimer's disease and intermittent fasting deteriorated insulin resistance in the fasting state but intermittent fasting decreased serum glucose levels after oral glucose challenge by increasing insulin secretion. Alzheimer's disease deteriorated short and spatial memory function compared to the Non-Alzheimer's disease, whereas intermittent fasting prevented memory loss in comparison to ad libitum. Unexpectedly

Accelerated intermittent Theta Burst stimulation for suicide risk in therapy-resistant depressed patients: a randomized, sham-controlled trial.

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Stefanie Desmyter

2016-09-01

Full Text Available Objectives We aimed to examine the effects and safety of accelerated intermittent Theta Burst Stimulation (iTBS on suicide risk in a group of treatment-resistant unipolar depressed patients, using an extensive suicide assessment scale. Methods In 50 therapy-resistant, antidepressant-free depressed patients, an intensive protocol of accelerated iTBS was applied over the left dorsolateral prefrontal cortex in a randomized, sham-controlled cross-over design. Patients received 20 iTBS sessions over 4 days. Suicide risk was assessed using the Beck Scale of Suicide ideation (BSI. Results The iTBS protocol was safe and well-tolerated. We observed a significant decrease of the BSI score over time, unrelated to active or sham stimulation and unrelated to depression-response. No worsening of suicidal ideation was observed. The effects of accelerated iTBS on mood and depression severity are reported in Duprat et al. (2016. The decrease in suicide risk lasted up to one month after baseline, even in depression non-responders. Conclusions This accelerated iTBS protocol was safe. The observed significant decrease in suicide risk was unrelated to active or sham stimulation and unrelated to depression response. Further sham-controlled research in suicidal depressed patients is necessary.(clinicaltrials.gov identifier: NCT01832805

Accelerated Intermittent Theta Burst Stimulation for Suicide Risk in Therapy-Resistant Depressed Patients: A Randomized, Sham-Controlled Trial.

Science.gov (United States)

Desmyter, Stefanie; Duprat, Romain; Baeken, Chris; Van Autreve, Sara; Audenaert, Kurt; van Heeringen, Kees

2016-01-01

Objectives: We aimed to examine the effects and safety of accelerated intermittent Theta Burst Stimulation (iTBS) on suicide risk in a group of treatment-resistant unipolar depressed patients, using an extensive suicide assessment scale. Methods: In 50 therapy-resistant, antidepressant-free depressed patients, an intensive protocol of accelerated iTBS was applied over the left dorsolateral prefrontal cortex (DLPFC) in a randomized, sham-controlled crossover design. Patients received 20 iTBS sessions over 4 days. Suicide risk was assessed using the Beck Scale of Suicide ideation (BSI). Results: The iTBS protocol was safe and well tolerated. We observed a significant decrease of the BSI score over time, unrelated to active or sham stimulation and unrelated to depression-response. No worsening of suicidal ideation was observed. The effects of accelerated iTBS on mood and depression severity are reported in Duprat et al. (2016). The decrease in suicide risk lasted up to 1 month after baseline, even in depression non-responders. Conclusions: This accelerated iTBS protocol was safe. The observed significant decrease in suicide risk was unrelated to active or sham stimulation and unrelated to depression response. Further sham-controlled research in suicidal depressed patients is necessary. (Clinicaltrials.gov identifier: NCT01832805).

Intermittent Rivers and Biodiversity. Large scale analyses between hydrology and ecology in intermittent rivers

OpenAIRE

Blanchard, Q.

2014-01-01

Intermittent rivers are characterized by a temporary interruption of their flow which can manifest in a variety of ways, as much on a spatial scale as on a temporal one. This particular aspect of intermittent river hydrology gives rise to unique ecosystems, combining both aquatic and terrestrial habitats. Neglected for a long time by scientists and once considered biologically depauperate and ecologically unimportant, these fragile habitats are nowadays acknowledged for their rendered service...

A prospective, randomized, blinded-endpoint, controlled study – continuous epidural infusion versus programmed intermittent epidural bolus in labor analgesia

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Joana Nunes

2016-09-01

Full Text Available Background: There is evidence that administration of a programmed intermittent epidural bolus (PIEB compared to continuous epidural infusion (CEI leads to greater analgesia efficacy and maternal satisfaction with decreased anesthetic interventions. Methods: In this study, 166 women with viable pregnancies were included. After an epidural loading dose of 10 mL with Ropivacaine 0.16% plus Sufentanil 10 μg, parturient were randomly assigned to one of three regimens: A – Ropivacaine 0.15% plus Sufentanil 0.2 μg/mL solution as continuous epidural infusion (5 mL/h, beginning immediately after the initial bolus; B – Ropivacaine 0.1% plus Sufentanil 0.2 μg/mL as programmed intermittent epidural bolus and C – Same solution as group A as programmed intermittent epidural bolus. PIEB regimens were programmed as 10 mL/h starting 60 min after the initial bolus. Rescue boluses of 5 mL of the same solution were administered, with the infusion pump. We evaluated maternal satisfaction using a verbal numeric scale from 0 to 10. We also evaluated adverse, maternal and neonatal outcomes. Results: We analyzed 130 pregnants (A = 60; B = 33; C = 37. The median verbal numeric scale for maternal satisfaction was 8.8 in group A; 8.6 in group B and 8.6 in group C (p = 0.83. We found a higher caesarean delivery rate in group A (56.7%; p = 0.02. No differences in motor block, instrumental delivery rate and neonatal outcomes were observed. Conclusions: Maintenance of epidural analgesia with programmed intermittent epidural bolus is associated with a reduced incidence of caesarean delivery with equally high maternal satisfaction and no adverse outcomes. Resumo: Justificativa: Há evidências de que a administração de um bolus epidural intermitente programado (BEIP comparada à infusão epidural contínua (IEC resulta em maior eficácia da analgesia e da satisfação materna, com redução das intervenções anestésicas. Métodos: Neste estudo, 166

Determine Efficacy of a Short Course of Montelukast in Children with Intermittent Asthma and Viral Infection

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Hamid Ahanchian

2013-12-01

Full Text Available Introduction Mild intermittent asthma is common in children and viral infections are responsible for the majority of exacerbations. As leukotrienes are potent inflammatory mediators, some studies have shown that Montelukast, a leukotriene receptor antagonist, may be effective on reduction of asthma symptom. To determine whether a short course of Montelukast in asthmatic children with common cold would modify the severity of an asthma episode.     Materials and Methods Children, aged 6-12 years with intermittent asthma participated in this randomized, double-blind, placebo-controlled clinical trial. Treatment with Montelukast or placebo was initiated at the onset of viral upper respiratory tract infection and continued for 7 days. Primary outcomes included the clinical manifestation: duration of episodes, daily symptom, nights symptoms and activity limitation. Secondary outcomes included the need for beta agonist usage, oral prednisolone, physician visit, hospital admission and school absence.   Results                                                              A total of 187 children with intermittent asthma were randomized, 93 to Montelukast group and 94 to placebo group. Montelukast significantly decreased the cough by 17.3% (P

Putting intelligent structured intermittent auscultation (ISIA) into practice.

Science.gov (United States)

Maude, Robyn M; Skinner, Joan P; Foureur, Maralyn J

2016-06-01

Fetal monitoring guidelines recommend intermittent auscultation for the monitoring of fetal wellbeing during labour for low-risk women. However, these guidelines are not being translated into practice and low-risk women birthing in institutional maternity units are increasingly exposed to continuous cardiotocographic monitoring, both on admission to hospital and during labour. When continuous fetal monitoring becomes routinised, midwives and obstetricians lose practical skills around intermittent auscultation. To support clinical practice and decision-making around auscultation modality, the intelligent structured intermittent auscultation (ISIA) framework was developed. The purpose of this discussion paper is to describe the application of intelligent structured intermittent auscultation in practice. The intelligent structured intermittent auscultation decision-making framework is a knowledge translation tool that supports the implementation of evidence into practice around the use of intermittent auscultation for fetal heart monitoring for low-risk women during labour. An understanding of the physiology of the materno-utero-placental unit and control of the fetal heart underpin the development of the framework. Intelligent structured intermittent auscultation provides midwives with a robust means of demonstrating their critical thinking and clinical reasoning and supports their understanding of normal physiological birth. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Acute Effects of Carbohydrate Supplementation on Intermittent Sports Performance.

Science.gov (United States)

Baker, Lindsay B; Rollo, Ian; Stein, Kimberly W; Jeukendrup, Asker E

2015-07-14

Intermittent sports (e.g., team sports) are diverse in their rules and regulations but similar in the pattern of play; that is, intermittent high-intensity movements and the execution of sport-specific skills over a prolonged period of time (~1-2 h). Performance during intermittent sports is dependent upon a combination of anaerobic and aerobic energy systems, both of which rely on muscle glycogen and/or blood glucose as an important substrate for energy production. The aims of this paper are to review: (1) potential biological mechanisms by which carbohydrate may impact intermittent sport performance; (2) the acute effects of carbohydrate ingestion on intermittent sport performance, including intermittent high-intensity exercise capacity, sprinting, jumping, skill, change of direction speed, and cognition; and (3) what recommendations can be derived for carbohydrate intake before/during exercise in intermittent sports based on the available evidence. The most researched intermittent sport is soccer but some sport-specific studies have also been conducted in other sports (e.g., rugby, field hockey, basketball, American football, and racquet sports). Carbohydrate ingestion before/during exercise has been shown in most studies to enhance intermittent high-intensity exercise capacity. However, studies have shown mixed results with regards to the acute effects of carbohydrate intake on sprinting, jumping, skill, change of direction speed, and cognition. In most of these studies the amount of carbohydrate consumed was ~30-60 g/h in the form of a 6%-7% carbohydrate solution comprised of sucrose, glucose, and/or maltodextrin. The magnitude of the impact that carbohydrate ingestion has on intermittent sport performance is likely dependent on the carbohydrate status of the individual; that is, carbohydrate ingestion has the greatest impact on performance under circumstances eliciting fatigue and/or hypoglycemia. Accordingly, carbohydrate ingestion before and during a game

The Efficacy of Programmed Intermittent Epidural Bolus for Postoperative Analgesia after Open Gynecological Surgery: A Randomized Double-Blinded Study

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Shiho Satomi

2018-01-01

Full Text Available Background. It is well known that the programmed intermittent epidural bolus (PIEB technique effectively provides epidural anesthesia in labor. This randomized double-blind trial compared the postoperative analgesic efficacy of PIEB with that of continuous epidural infusion (CEI in patients undergoing gynecological surgery under combined general-epidural anesthesia. Methods. Patients undergoing open gynecological surgery under combined general-epidural anesthesia were randomized at a 1 : 1 ratio to receive PIEB or CEI. In the PIEB group, the pump delivered 4 mL ropivacaine 0.2% plus fentanyl 2 μg/mL every hour. In the CEI group, the pump delivered the same solution at a rate of 4 mL/h. In both groups, additional 4 mL boluses of ropivacaine 0.2% plus fentanyl 2 μg/mL were provided, when necessary, by patient-controlled epidural analgesia after surgery. The primary outcome was the total ropivacaine dose 40 hours after surgery. The secondary outcomes were the number of PCEA boluses and postoperative pain (evaluated on an 11-point numerical rating scale 3, 24, and 48 hours after surgery. Results. In total, 57 patients were randomized (n=28 and 29 in the PIEB and CEI groups, resp.. The two groups differ significantly in terms of the total ropivacaine dose 40 hours after surgery (mean (standard deviation: 155.38 (4.55 versus 159.73 (7.87 mL, P=0.016. Compared to the CEI group, the PIEB group had significantly lower numerical rating scale scores 3 hours (median [lower–upper quartiles]: 0 [0–0.5] versus 3 [0–5.5], P=0.002, 24 hours (1 [0–2] versus 3 [1–4], P=0.003, and 48 hours (1 [0–2] versus 2 [2–3.5], P=0.002 after surgery. Conclusion. PIEB was better than CEI in terms of providing postoperative analgesia after open gynecological surgery under combined general-epidural anesthesia.

Modeling Integrated Water-User Decisions with Intermittent Supplies

Science.gov (United States)

Lund, J. R.; Rosenberg, D.

2006-12-01

We present an economic-engineering method to estimate urban water use demands with intermittent water supplies. A two-stage, probabilistic optimization formulation includes a wide variety of water supply enhancement and conservation actions that individual households can adopt to meet multiple water quality uses with uncertain water availability. We embed the optimization in Monte-Carlo simulations to show aggregate effects at a utility (citywide) scale for a population of user conditions and decisions. Parametric analysis provides derivations of supply curves to subsidize conservation, demand responses to alternative pricing, and customer willingness-to-pay to avoid shortages. Results show a good empirical fit for the average and distribution of billed residential water use in Amman, Jordan. Additional outputs give likely market penetration rates for household conservation actions, associated water savings, and subsidies required to entice further adoption. We discuss new insights to size, target, market, and finance conservation programs and interpret a demand curve with block pricing.

Optimizing an Intermittent Stretch Paradigm Using ERK1/2 Phosphorylation Results in Increased Collagen Synthesis in Engineered Ligaments

Science.gov (United States)

Paxton, Jennifer Z.; Hagerty, Paul; Andrick, Jonathan J.

2012-01-01

Dynamic mechanical input is believed to play a critical role in the development of functional musculoskeletal tissues. To study this phenomenon, cyclic uniaxial mechanical stretch was applied to engineered ligaments using a custom-built bioreactor and the effects of different stretch frequency, amplitude, and duration were determined. Stretch acutely increased the phosphorylation of p38 (3.5±0.74-fold), S6K1 (3.9±0.19-fold), and ERK1/2 (2.45±0.32-fold). The phosphorylation of ERK1/2 was dependent on time, rather than on frequency or amplitude, within these constructs. ERK1/2 phosphorylation was similar following stretch at frequencies from 0.1 to 1 Hz and amplitudes from 2.5% to 15%, whereas phosphorylation reached maximal levels at 10 min of stretch and returned toward basal within 60 min of stretch. Following a single 10-min bout of cyclic stretch, the cells remained refractory to a second stretch for up to 6 h. Using the phosphorylation of ERK1/2 as a guide, the optimum stretch paradigm was hypothesized to be 10 min of stretch at 2.5% of resting length repeated every 6 h. Consistent with this hypothesis, 7 days of stretch using this optimized intermittent stretch program increased the collagen content of the grafts more than a continuous stretch program (CTL=3.1%±0.44%; CONT=4.8%±0.30%; and INT=5.9%±0.56%). These results suggest that short infrequent bouts of loading are optimal for improving engineered tendon and ligament physiology. PMID:21902469

Numerical optimization approach for resonant electromagnetic vibration transducer designed for random vibration

International Nuclear Information System (INIS)

Spreemann, Dirk; Hoffmann, Daniel; Folkmer, Bernd; Manoli, Yiannos

2008-01-01

This paper presents a design and optimization strategy for resonant electromagnetic vibration energy harvesting devices. An analytic expression for the magnetic field of cylindrical permanent magnets is used to build up an electromagnetic subsystem model. This subsystem is used to find the optimal resting position of the oscillating mass and to optimize the geometrical parameters (shape and size) of the magnet and coil. The objective function to be investigated is thereby the maximum voltage output of the transducer. An additional mechanical subsystem model based on well-known equations describing the dynamics of spring–mass–damper systems is established to simulate both nonlinear spring characteristics and the effect of internal limit stops. The mechanical subsystem enables the identification of optimal spring characteristics for realistic operation conditions such as stochastic vibrations. With the overall transducer model, a combination of both subsystems connected to a simple electrical circuit, a virtual operation of the optimized vibration transducer excited by a measured random acceleration profile can be performed. It is shown that the optimization approach results in an appreciable increase of the converter performance

Coherent Structures and Intermittency in Plasma Turbulence

International Nuclear Information System (INIS)

Das, Amita; Kaw, Predhiman; Sen, Abhijit

2008-01-01

The paper discusses some fundamental issues related to the phenomenon of intermittency in plasma turbulence with particular reference to experimental observations in fusion devices. Intermittency is typically associated with the presence of coherent structures in turbulence. Since coherent structures can play an important role in governing the transport properties of a system they have received a great deal of attention in fusion research. We review some of the experimental measurements and numerical simulation studies on the presence and formation of coherent structures in plasmas and discuss their relevance to intermittency. Intermittency, as widely discussed in the context of neutral fluid turbulence, implies multiscaling behaviour in contrast to self-similar scaling patterns observed in self organized criticality (SOC) phenomenon. The experimental evidence from plasma turbulence measurements reveal a mixed picture--while some observations support the SOC model description others indicate the presence of multiscaling behaviour. We discuss these results in the light of our present understanding of plasma turbulence and in terms of certain unique aspects of intermittency as revealed by fluid models of plasmas.

The impact of intermittent or sustained carbon dioxide on intermittent hypoxia initiated respiratory plasticity. What is the effect of these combined stimuli on apnea severity?

Science.gov (United States)

Mateika, Jason H; Panza, Gino; Alex, Raichel; El-Chami, Mohamad

2017-10-31

The following review explores the effect that intermittent or sustained hypercapnia coupled to intermittent hypoxia has on respiratory plasticity. The review explores published work which suggests that intermittent hypercapnia leads to long-term depression of respiration when administered in isolation and prevents the initiation of long-term facilitation when administered in combination with intermittent hypoxia. The review also explores the impact that sustained hypercapnia alone and in combination with intermittent hypoxia has on the magnitude of long-term facilitation. After exploring the outcomes linked to intermittent hypoxia/hypercapnia and intermittent hypoxia/sustained hypercapnia the translational relevance of the outcomes as it relates to breathing stability during sleep is addressed. The likelihood that naturally induced cycles of intermittent hypoxia, coupled to oscillations in carbon dioxide that range between hypocapnia and hypercapnia, do not initiate long-term facilitation is addressed. Moreover, the conditions under which intermittent hypoxia/sustained hypercapnia could serve to improve breathing stability and mitigate co-morbidities associated with sleep apnea are considered. Published by Elsevier B.V.

Intermittently renewable energy, optimal capacity mix and prices in a deregulated electricity market

International Nuclear Information System (INIS)

Milstein, Irena; Tishler, Asher

2011-01-01

This paper assesses the effect of intermittently renewable energy on generation capacity mix and market prices. We consider two generating technologies: (1) conventional fossil-fueled technology such as combined cycle gas turbine (CCGT), and (2) sunshine-dependent renewable technology such as photovoltaic cells (PV). In the first stage of the model (game), when only the probability distribution functions of future daily electricity demand and sunshine are known, producers maximize their expected profits by determining the CCGT and PV capacity to be constructed. In the second stage, once daily demand and sunshine conditions become known, each producer selects the daily production by each technology, taking the capacities of both technologies as given, and subject to the availability of the PV capacity, which can be used only if the sun is shining. Using real-world data for Israel, we confirm that the introduction of PV technology amplifies price volatility. A large reduction in PV capacity cost increases PV adoption but may also raise the average price. Thus, when considering the promotion of renewable energy to reduce CO 2 emissions, regulators should assess the behavior of the electricity market, particularly with respect to characteristics of renewable technologies and demand and supply uncertainties. - Research Highlights: → This paper assesses the effect of intermittently renewable energy on generation capacity mix and market prices. → We consider two generating technologies: (1) conventional fossil-fueled technology such as CCGT and (2) sunshine-dependent renewable technology such as photovoltaic cells (PV). →Using real-world data for Israel, we confirm that the introduction of PV technology amplifies price volatility. → A large reduction in PV capacity cost increases PV adoption but may also raise the average price.

Scheduled Intermittent Screening with Rapid Diagnostic Tests and Treatment with Dihydroartemisinin-Piperaquine versus Intermittent Preventive Therapy with Sulfadoxine-Pyrimethamine for Malaria in Pregnancy in Malawi: An Open-Label Randomized Controlled Trial.

Directory of Open Access Journals (Sweden)

Mwayiwawo Madanitsa

2016-09-01

Full Text Available In Africa, most plasmodium infections during pregnancy remain asymptomatic, yet are associated with maternal anemia and low birthweight. WHO recommends intermittent preventive therapy in pregnancy with sulfadoxine-pyrimethamine (IPTp-SP. However, sulfadoxine-pyrimethamine (SP efficacy is threatened by high-level parasite resistance. We conducted a trial to evaluate the efficacy and safety of scheduled intermittent screening with malaria rapid diagnostic tests (RDTs and treatment of RDT-positive women with dihydroartemisinin-piperaquine (DP as an alternative strategy to IPTp-SP.This was an open-label, two-arm individually randomized superiority trial among HIV-seronegative women at three sites in Malawi with high SP resistance. The intervention consisted of three or four scheduled visits in the second and third trimester, 4 to 6 wk apart. Women in the IPTp-SP arm received SP at each visit. Women in the intermittent screening and treatment in pregnancy with DP (ISTp-DP arm were screened for malaria at every visit and treated with DP if RDT-positive. The primary outcomes were adverse live birth outcome (composite of small for gestational age, low birthweight [<2,500 g], or preterm birth [<37 wk] in paucigravidae (first or second pregnancy and maternal or placental plasmodium infection at delivery in multigravidae (third pregnancy or higher. Analysis was by intention to treat. Between 21 July 2011 and 18 March 2013, 1,873 women were recruited (1,155 paucigravidae and 718 multigravidae. The prevalence of adverse live birth outcome was similar in the ISTp-DP (29.9% and IPTp-SP (28.8% arms (risk difference = 1.08% [95% CI -3.25% to 5.41%]; all women: relative risk [RR] = 1.04 [95% CI 0.90-1.20], p = 0.625; paucigravidae: RR = 1.10 [95% CI 0.92-1.31], p = 0.282; multigravidae: RR = 0.92 [95% CI 0.71-1.20], p = 0.543. The prevalence of malaria at delivery was higher in the ISTp-DP arm (48.7% versus 40.8%; risk difference = 7.85%, [95% CI 3

Intermittent hypoxia increases insulin resistance in genetically obese mice.

Science.gov (United States)

Polotsky, Vsevolod Y; Li, Jianguo; Punjabi, Naresh M; Rubin, Arnon E; Smith, Philip L; Schwartz, Alan R; O'Donnell, Christopher P

2003-10-01

Obstructive sleep apnoea, a syndrome that leads to recurrent intermittent hypoxia, is associated with insulin resistance in obese individuals, but the mechanisms underlying this association remain unknown. We utilized a mouse model to examine the effects of intermittent hypoxia on insulin resistance in lean C57BL/6J mice and leptin-deficient obese (C57BL/6J-Lepob) mice. In lean mice, exposure to intermittent hypoxia for 5 days (short term) resulted in a decrease in fasting blood glucose levels (from 173 +/- 11 mg dl-1 on day 0 to 138 +/- 10 mg dl-1 on day 5, P obese mice, short-term intermittent hypoxia led to a decrease in blood glucose levels accompanied by a 607 +/- 136 % (P intermittent hypoxia was completely abolished by prior leptin infusion. Obese mice exposed to intermittent hypoxia for 12 weeks (long term) developed a time-dependent increase in fasting serum insulin levels (from 3.6 +/- 1.1 ng ml-1 at baseline to 9.8 +/- 1.8 ng ml-1 at week 12, P intermittent hypoxia is dependent on the disruption of leptin pathways.

Comparison of an intermittent high-intensity vs continuous low-intensity physiotherapy service over 12 months in community-dwelling people with stroke: a randomized trial.

Science.gov (United States)

Hesse, S; Welz, A; Werner, C; Quentin, B; Wissel, J

2011-02-01

This study compared two modes of physiotherapy service over 12 months in community-dwelling people with stroke, either following a train-wait train paradigm by providing bouts of intense physiotherapy, or a continuous less intense programme. Randomized trial. Community-dwelling people with stroke. Fifty patients, first-time stroke, discharged home, following inpatient rehabilitation, allocated to two groups, A and B. Over 12 months, Group A (n = 25) received three two-month blocks of therapy at home, each block contained four 30 to 45 minute sessions per week, totalling 96 sessions. Group B (n = 25) continuously received two 30 to 45 minute sessions per week, totalling 104 sessions. Primary Rivermead Mobility Index (0-15), secondary upper- and lower-limb motor functions, Activities of Daily Living competence, tone and number of falls. Both groups were comparable at onset, the mean age in Group A (B) was 62.4 (61.9) years. A and B patients equally improved functions over time, between group differences did not occur. The initial (terminal) Rivermead Mobility Index was 9.4 ± 2.8 (12.2 ± 2.1) in Group A, and 8.5 ± 3.5 (11.2 ± 2.7) in Group B. More Group B patients fell seriously (7 versus 1). The intermittent high-intensity and continuous low-intensity therapy protocols were equally effective, the sheer intensity seems more important than the time-mode of application. The relatively young patients functionally improved in the first year after stroke, the reduced risk of serious falls in the intermittent high-intensity group should be validated.

The Yo-Yo intermittent recovery test

DEFF Research Database (Denmark)

Bangsbo, Jens; Iaia, F. Marcello; Krustrup, Peter

2008-01-01

The two Yo-Yo intermittent recovery (IR) tests evaluate an individual's ability to repeatedly perform intense exercise. The Yo-Yo IR level 1 (Yo-Yo IR1) test focuses on the capacity to carry out intermittent exercise leading to a maximal activation of the aerobic system, whereas Yo-Yo IR level 2...

Dynamic characterizers of spatiotemporal intermittency

OpenAIRE

Gupte, Neelima; Jabeen, Zahera

2006-01-01

Systems of coupled sine circle maps show regimes of spatiotemporally intermittent behaviour with associated scaling exponents which belong to the DP class, as well as regimes of spatially intermittent behaviour (with associated regular dynamical behaviour) which do not belong to the DP class. Both types of behaviour are seen along the bifurcation boundaries of the synchronized solutions, and contribute distinct signatures to the dynamical characterizers of the system, viz. the distribution of...

The optimal injection technique for the osteoarthritic ankle: A randomized, cross-over trial

NARCIS (Netherlands)

Witteveen, Angelique G. H.; Kok, Aimee; Sierevelt, Inger N.; Kerkhoffs, Gino M. M. J.; van Dijk, C. Niek

2013-01-01

Background: To optimize the injection technique for the osteoarthritic ankle in order to enhance the effect of intra-articular injections and minimize adverse events. Methods: Randomized cross-over trial. Comparing two injection techniques in patients with symptomatic ankle osteoarthritis. Patients

Does intermittent pneumatic compression reduce the risk of post stroke deep vein thrombosis? The CLOTS 3 trial: study protocol for a randomized controlled trial

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Dennis Martin

2012-03-01

Full Text Available Abstract Background Approximately 80,000 patients each year are admitted to UK hospitals with an acute stroke and are immobile. At least 10% will develop a proximal Deep Vein Thrombosis in the first month and 1.5% a pulmonary embolus. Although hydration, antiplatelet treatment and early mobilisation may reduce the risk of deep vein thrombosis, there are currently no preventive strategies which have been clearly shown to be both effective and safe. Anticoagulation increases the risks of bleeding and compression stockings are ineffective. Systematic reviews of small randomized trials of intermittent pneumatic compression have shown that this reduces the risk of deep vein thrombosis in patients undergoing surgery, but that there are few data concerning its use after stroke. The CLOTS trial 3 aims to determine whether, compared with best medical care, best medical care plus intermittent pneumatic compression in immobile stroke patients reduces the risk of proximal deep vein thrombosis. Methods/Design CLOTS Trial 3 is a parallel group multicentre trial; with centralized randomisation (minimisation to ensure allocation concealment. Over 80 centres in the UK will recruit 2800 immobile stroke patients within the first 3 days of their hospital admission. Patients will be allocated to best medical care or best medical care plus intermittent pneumatic compression. Ultrasonographers will perform a Compression Duplex Ultrasound Scan to detect deep vein thrombosis in each treatment group at about 7-10 days and 25-30 days. The primary outcome cluster includes symptomatic or asymptomatic deep vein thrombosis in the popliteal or femoral veins detected on either scan. Patients are then followed up by postal or telephone questionnaire at 6 months from randomisation to detect later symptomatic deep vein thrombosis and pulmonary emboli and to establish their functional outcome (Oxford handicap scale and quality of life (EQ5D-3 L. The ultrasonographers performing the

On-off intermittency and coherent bursting in stochastically-driven coupled maps

International Nuclear Information System (INIS)

Metta, Sabino; Provenzale, Antonello; Spiegel, Edward A.

2010-01-01

On-off intermittency is a phase space mechanism for bursting in dynamical systems. Here we recall how the simple example of a logistic map with a time-dependent control parameter, considered as a dynamical variable of the system, gives rise to bursting or on-off behavior. We show that, for a given realization of the driver, a stochastically driven logistic map in the on-off intermittent regime always converges to the same temporal dynamics, independently of initial conditions. In that sense, the map is not chaotic. We then explore the behavior of two coupled on-off logistic maps, each driven by a separate random process, and show that, for a wide range of coupling strengths, bursting becomes at least partially coherent. The bursting coherence has a smooth dependence on the coupling parameter and no sharp transition from coherence to incoherence is detected. In the system of two coupled on-off maps studied here, coherent bursting is rooted in the behavior during off phases when the mapped coordinates take on extremely small values.

Acute Effects of Carbohydrate Supplementation on Intermittent Sports Performance

Directory of Open Access Journals (Sweden)

Lindsay B. Baker

2015-07-01

Full Text Available Intermittent sports (e.g., team sports are diverse in their rules and regulations but similar in the pattern of play; that is, intermittent high-intensity movements and the execution of sport-specific skills over a prolonged period of time (~1–2 h. Performance during intermittent sports is dependent upon a combination of anaerobic and aerobic energy systems, both of which rely on muscle glycogen and/or blood glucose as an important substrate for energy production. The aims of this paper are to review: (1 potential biological mechanisms by which carbohydrate may impact intermittent sport performance; (2 the acute effects of carbohydrate ingestion on intermittent sport performance, including intermittent high-intensity exercise capacity, sprinting, jumping, skill, change of direction speed, and cognition; and (3 what recommendations can be derived for carbohydrate intake before/during exercise in intermittent sports based on the available evidence. The most researched intermittent sport is soccer but some sport-specific studies have also been conducted in other sports (e.g., rugby, field hockey, basketball, American football, and racquet sports. Carbohydrate ingestion before/during exercise has been shown in most studies to enhance intermittent high-intensity exercise capacity. However, studies have shown mixed results with regards to the acute effects of carbohydrate intake on sprinting, jumping, skill, change of direction speed, and cognition. In most of these studies the amount of carbohydrate consumed was ~30–60 g/h in the form of a 6%–7% carbohydrate solution comprised of sucrose, glucose, and/or maltodextrin. The magnitude of the impact that carbohydrate ingestion has on intermittent sport performance is likely dependent on the carbohydrate status of the individual; that is, carbohydrate ingestion has the greatest impact on performance under circumstances eliciting fatigue and/or hypoglycemia. Accordingly, carbohydrate ingestion before

Managing server clusters on intermittent power

Directory of Open Access Journals (Sweden)

Navin Sharma

2015-12-01

Full Text Available Reducing the energy footprint of data centers continues to receive significant attention due to both its financial and environmental impact. There are numerous methods that limit the impact of both factors, such as expanding the use of renewable energy or participating in automated demand-response programs. To take advantage of these methods, servers and applications must gracefully handle intermittent constraints in their power supply. In this paper, we propose blinking—metered transitions between a high-power active state and a low-power inactive state—as the primary abstraction for conforming to intermittent power constraints. We design Blink, an application-independent hardware–software platform for developing and evaluating blinking applications, and define multiple types of blinking policies. We then use Blink to design both a blinking version of memcached (BlinkCache and a multimedia cache (GreenCache to demonstrate how application characteristics affect the design of blink-aware distributed applications. Our results show that for BlinkCache, a load-proportional blinking policy combines the advantages of both activation and synchronous blinking for realistic Zipf-like popularity distributions and wind/solar power signals by achieving near optimal hit rates (within 15% of an activation policy, while also providing fairer access to the cache (within 2% of a synchronous policy for equally popular objects. In contrast, for GreenCache, due to multimedia workload patterns, we find that a staggered load proportional blinking policy with replication of the first chunk of each video reduces the buffering time at all power levels, as compared to activation or load-proportional blinking policies.

Forces and energetics of intermittent swimming

Science.gov (United States)

Floryan, Daniel; Van Buren, Tyler; Smits, Alexander J.

2017-08-01

Experiments are reported on intermittent swimming motions. Water tunnel experiments on a nominally two-dimensional pitching foil show that the mean thrust and power scale linearly with the duty cycle, from a value of 0.2 all the way up to continuous motions, indicating that individual bursts of activity in intermittent motions are independent of each other. This conclusion is corroborated by particle image velocimetry (PIV) flow visualizations, which show that the main vortical structures in the wake do not change with duty cycle. The experimental data also demonstrate that intermittent motions are generally energetically advantageous over continuous motions. When metabolic energy losses are taken into account, this conclusion is maintained for metabolic power fractions less than 1.

Effect of intermittent versus daily calorie restriction on changes in weight and patient reported outcomes in people with multiple sclerosis

Science.gov (United States)

An intermittent fasting or calorie restriction diet has favorable effects in the mouse forms of multiple sclerosis (MS) and may provide additional anti-inflammatory and neuroprotective advantages beyond benefits obtained from weight loss alone. We conducted a pilot randomized controlled feeding stud...

On Generating Optimal Signal Probabilities for Random Tests: A Genetic Approach

Directory of Open Access Journals (Sweden)

M. Srinivas

1996-01-01

Full Text Available Genetic Algorithms are robust search and optimization techniques. A Genetic Algorithm based approach for determining the optimal input distributions for generating random test vectors is proposed in the paper. A cost function based on the COP testability measure for determining the efficacy of the input distributions is discussed. A brief overview of Genetic Algorithms (GAs and the specific details of our implementation are described. Experimental results based on ISCAS-85 benchmark circuits are presented. The performance of our GAbased approach is compared with previous results. While the GA generates more efficient input distributions than the previous methods which are based on gradient descent search, the overheads of the GA in computing the input distributions are larger.

Intermittent cranial lung herniation in two dogs.

Science.gov (United States)

Guglielmini, Carlo; De Simone, Antonio; Valbonetti, Luca; Diana, Alessia

2007-01-01

Two aged dogs with chronic obstructive airway disease were evaluated because of intermittent swelling of the ventral cervical region. Radiographs made at expiration and caudal positioning of the forelimbs allowed identification of intermittent cervical lung herniation of the left and right cranial lung lobe in both dogs. Pulmonary hyperinflation, increased expiratory effort, and chronic coughing were considered responsible for the lung herniation. Cervical lung hernia should be included in the differential diagnoses of intermittent cervical swelling in dogs with chronic respiratory disorders associated with increased expiratory effort and chronic coughing.

Interpolating between random walks and optimal transportation routes: Flow with multiple sources and targets

Science.gov (United States)

Guex, Guillaume

2016-05-01

In recent articles about graphs, different models proposed a formalism to find a type of path between two nodes, the source and the target, at crossroads between the shortest-path and the random-walk path. These models include a freely adjustable parameter, allowing to tune the behavior of the path toward randomized movements or direct routes. This article presents a natural generalization of these models, namely a model with multiple sources and targets. In this context, source nodes can be viewed as locations with a supply of a certain good (e.g. people, money, information) and target nodes as locations with a demand of the same good. An algorithm is constructed to display the flow of goods in the network between sources and targets. With again a freely adjustable parameter, this flow can be tuned to follow routes of minimum cost, thus displaying the flow in the context of the optimal transportation problem or, by contrast, a random flow, known to be similar to the electrical current flow if the random-walk is reversible. Moreover, a source-targetcoupling can be retrieved from this flow, offering an optimal assignment to the transportation problem. This algorithm is described in the first part of this article and then illustrated with case studies.

Convergence of quasi-optimal Stochastic Galerkin methods for a class of PDES with random coefficients

KAUST Repository

Beck, Joakim; Nobile, Fabio; Tamellini, Lorenzo; Tempone, Raul

2014-01-01

In this work we consider quasi-optimal versions of the Stochastic Galerkin method for solving linear elliptic PDEs with stochastic coefficients. In particular, we consider the case of a finite number N of random inputs and an analytic dependence of the solution of the PDE with respect to the parameters in a polydisc of the complex plane CN. We show that a quasi-optimal approximation is given by a Galerkin projection on a weighted (anisotropic) total degree space and prove a (sub)exponential convergence rate. As a specific application we consider a thermal conduction problem with non-overlapping inclusions of random conductivity. Numerical results show the sharpness of our estimates. © 2013 Elsevier Ltd. All rights reserved.

Convergence of quasi-optimal Stochastic Galerkin methods for a class of PDES with random coefficients

KAUST Repository

Beck, Joakim

2014-03-01

In this work we consider quasi-optimal versions of the Stochastic Galerkin method for solving linear elliptic PDEs with stochastic coefficients. In particular, we consider the case of a finite number N of random inputs and an analytic dependence of the solution of the PDE with respect to the parameters in a polydisc of the complex plane CN. We show that a quasi-optimal approximation is given by a Galerkin projection on a weighted (anisotropic) total degree space and prove a (sub)exponential convergence rate. As a specific application we consider a thermal conduction problem with non-overlapping inclusions of random conductivity. Numerical results show the sharpness of our estimates. © 2013 Elsevier Ltd. All rights reserved.

Beneficial effects of intermittent suction and pressure treatment in intermittent claudication

DEFF Research Database (Denmark)

Mehlsen, J; Himmelstrup, H; Himmelstrup, Bodil

1993-01-01

administration. The treatment caused significant increments in the ADP thresholds for platelet aggregation, while the effects on fibrinolysis were uncertain. It is concluded that intermittent suction and pressure treatment offers a new approach for conservative treatment of intermittent claudication....... participated in an open trial investigating the possible effects of the treatment on platelet aggregation and fibrinolysis. Pain-free and maximal walking distances were measured on a treadmill, and systolic blood pressure was measured on the upper limb, the ankle, and the first toe bilaterally. The threshold...... for adenosine diphosphate (ADP)-induced platelet aggregation was tested, and the fibrinolytic activity was estimated from the euglobulin clot lysis time. Active treatment resulted in significant improvements in pain-free and maximal walking distances, whereas no changes could be found during placebo...

A prospective randomized comparison of continuous hemihepatic with intermittent total hepatic inflow occlusion in hepatectomy for liver tumors.

Science.gov (United States)

Liang, Guanlin; Wen, Tianfu; Yan, Lunan; Li, B O; Wu, Guochang; Yang, Jian; Lu, Bo; Chen, Zheyu; Liao, Zhixue; Ran, Shun; Yu, Zhang

2009-01-01

To evaluate whether continuous hemihepatic inflow occlusion (HHO) during hepatectomy can be safer than and be as effective as intermittent total hepatic inflow occlusion (THO) in reducing blood loss. Eighty patients undergoing liver resections were included in a prospective randomized study comparing the intra- and postoperative course under THO (n=40) or HHO (n=40). THO was performed with periods of 20 minutes of occlusion and 5 minutes of releasing, while HHO was performed with continuous occlusion. The surface area of liver transection, amount of blood loss, measurements of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and postoperative evolution were recorded. The two groups were similar at entry in terms of preoperative liver function and in the proportion of patients experiencing major hepatectomy. The total ischemic time of the two groups was similar (p=0.37), but the operative time in the THO group was longer than in the HHO group (p=0.02). No significant difference was found between the HHO and THO group in blood loss during liver parenchyma transection (p=0.14), the elevations of ALT and AST on the first postoperative day (ALT: p=0.12; AST: p=0.66) and postoperative morbidity (p=0.35). On the basis of our findings, if it is feasible, continuous HHO is recommended for complex liver resection.

Intermittent behavior of the logistic system

Science.gov (United States)

Mayer-Kress, G.; Haken, H.

1981-03-01

In the discrete logistic model a transition to chaotic behavior via intermittency occurs in a neighborhood of periodic bands. Intermittent behavior is also induced if a stable periodic orbit is perturbed by low-level external noise, whereas alterations due to computer digitalisation produce remarkable periodicities. We compare our numerical results with the predictions of Pomeau and Manneville for the Lorenz system.

Safety and adherence to intermittent pre-exposure prophylaxis (PrEP) for HIV-1 in African men who have sex with men and female sex workers.

Science.gov (United States)

Mutua, Gaudensia; Sanders, Eduard; Mugo, Peter; Anzala, Omu; Haberer, Jessica E; Bangsberg, David; Barin, Burc; Rooney, James F; Mark, David; Chetty, Paramesh; Fast, Patricia; Priddy, Frances H

2012-01-01

Little is known about safety of and adherence to intermittent HIV PrEP regimens, which may be more feasible than daily dosing in some settings. We present safety and adherence data from the first trial of an intermittent PrEP regimen among Kenyan men who have sex with men (MSM) and female sex workers (FSW). MSM and FSW were randomized to daily oral FTC/TDF or placebo, or intermittent (Monday, Friday and within 2 hours after sex, not to exceed one dose per day) oral FTC/TDF or placebo in a 2:1:2:1 ratio; volunteers were followed monthly for 4 months. Adherence was assessed with the medication event monitoring system (MEMS). Sexual activity data were collected via daily text message (SMS) queries and timeline followback interviews with a one-month recall period. Sixty-seven men and 5 women were randomized into the study. Safety was similar among all groups. Median MEMS adherence rates were 83% [IQR: 63-92] for daily dosing and 55% [IQR:28-78] for fixed intermittent dosing (p = 0.003), while adherence to any post-coital doses was 26% [IQR:14-50]. SMS response rates were low, which may have impaired measurement of post-coital dosing adherence. Acceptability of PrEP was high, regardless of dosing regimen. Adherence to intermittent dosing regimens, fixed doses, and in particular coitally-dependent doses, may be more difficult than adherence to daily dosing. However, intermittent dosing may still be appropriate for PrEP if intracellular drug levels, which correlate with prevention of HIV acquisition, can be attained with less than daily dosing and if barriers to adherence can be addressed. Additional drug level data, qualitative data on adherence barriers, and better methods to measure sexual activity are necessary to determine whether adherence to post-coital PrEP could be comparable to more standard regimens. ClinicalTrials.gov NCT00971230.

A wavelet-based intermittency detection technique from PIV investigations in transitional boundary layers

Science.gov (United States)

Simoni, Daniele; Lengani, Davide; Guida, Roberto

2016-09-01

The transition process of the boundary layer growing over a flat plate with pressure gradient simulating the suction side of a low-pressure turbine blade and elevated free-stream turbulence intensity level has been analyzed by means of PIV and hot-wire measurements. A detailed view of the instantaneous flow field in the wall-normal plane highlights the physics characterizing the complex process leading to the formation of large-scale coherent structures during breaking down of the ordered motion of the flow, thus generating randomized oscillations (i.e., turbulent spots). This analysis gives the basis for the development of a new procedure aimed at determining the intermittency function describing (statistically) the transition process. To this end, a wavelet-based method has been employed for the identification of the large-scale structures created during the transition process. Successively, a probability density function of these events has been defined so that an intermittency function is deduced. This latter strictly corresponds to the intermittency function of the transitional flow computed trough a classic procedure based on hot-wire data. The agreement between the two procedures in the intermittency shape and spot production rate proves the capability of the method in providing the statistical representation of the transition process. The main advantages of the procedure here proposed concern with its applicability to PIV data; it does not require a threshold level to discriminate first- and/or second-order time-derivative of hot-wire time traces (that makes the method not influenced by the operator); and it provides a clear evidence of the connection between the flow physics and the statistical representation of transition based on theory of turbulent spot propagation.

Intermittent hydronephrosis

International Nuclear Information System (INIS)

Knop, J.; Vogel, H.; Hupe, W.

1981-01-01

An intermittent hydronephrosis was observed in a 40-year old patient. This disease pattern is due to an incongruity between the formation of urine and the transport capacity in the ureteropelvic junction. The latent impediment of flow becomes manifest with increased urine secretion. Irreversible renal damage can be the result of the repeatedly occurring hydronephrotic crises. (orig.) [de

Multi-region optimal deployment of renewable energy considering different interregional transmission scenarios

International Nuclear Information System (INIS)

Wang, Ge; Zhang, Qi; Mclellan, Benjamin C.; Li, Hailong

2016-01-01

Renewable energy is expected to play much more important role in future low-carbon energy system, however, renewable energy has problems with regard to load-following and regional imbalance. This study aims to plan the deployment of intermittent renewable energy in multiple regions considering the impacts of regional natural conditions and generation capacity mix as well as interregional transmission capacity using a multi-region dynamic optimization model. The model was developed to find optimized development paths toward future smart electricity systems with high level penetration of intermittent renewable energy considering regional differences and interregional transmission at national scale. As a case study, the model was applied to plan power generation in nine interconnected regions in Japan out to 2030. Four scenarios were proposed with different supporting policies for the interregional power transmission infrastructures and different nuclear power phase-out scenarios. The analysis results show that (i) the government's support for power transmission infrastructures is vital important to develop more intermittent renewable energy in appropriate regions and utilize renewable energy more efficiently; (ii) nuclear and renewable can complement rather than replace each other if enough interregional transmission capacity is provided. - Highlights: • Plan the optimal deployment of intermittent renewable energy in multiple regions. • A multi-region dynamic optimization model was developed. • The impacts of natural conditions and interregional transmission are studied. • The government's support for transmission is vital important for renewable energy. • Nuclear and renewable can complement rather than replace each other.

ARSTEC, Nonlinear Optimization Program Using Random Search Method

International Nuclear Information System (INIS)

Rasmuson, D. M.; Marshall, N. H.

1979-01-01

1 - Description of problem or function: The ARSTEC program was written to solve nonlinear, mixed integer, optimization problems. An example of such a problem in the nuclear industry is the allocation of redundant parts in the design of a nuclear power plant to minimize plant unavailability. 2 - Method of solution: The technique used in ARSTEC is the adaptive random search method. The search is started from an arbitrary point in the search region and every time a point that improves the objective function is found, the search region is centered at that new point. 3 - Restrictions on the complexity of the problem: Presently, the maximum number of independent variables allowed is 10. This can be changed by increasing the dimension of the arrays

Compensatory mechanisms activated with intermittent energy restriction

DEFF Research Database (Denmark)

Coutinho, Sílvia Ribeiro; Halset, Eline Holli; Gåsbakk, Sigrid

2018-01-01

Background & aims: Strong compensatory responses, with reduced resting metabolic rate (RMR), increased exercise efficiency (ExEff) and appetite, are activated when weight loss (WL) is achieved with continuous energy restriction (CER), which try to restore energy balance. Intermittent energy...... restriction (IER), where short spells of energy restriction are interspaced by periods of habitual energy intake, may offer some protection in minimizing those responses. We aimed to compare the effect of IER versus CER on body composition and the compensatory responses induced by WL. Methods: 35 adults (age......: 39 ± 9 y) with obesity (BMI: 36 ± 4 kg/m2) were randomized to lose a similar weight with an IER (N = 18) or a CER (N = 17) diet over a 12 week period. Macronutrient composition and overall energy restriction (33% reduction) were similar between groups. Body weight/composition, RMR, fasting...

Characterization of intermittency in zooplankton behaviour in turbulence.

Science.gov (United States)

Michalec, François-Gaël; Schmitt, François G; Souissi, Sami; Holzner, Markus

2015-10-01

We consider Lagrangian velocity differences of zooplankters swimming in still water and in turbulence. Using cumulants, we quantify the intermittency properties of their motion recorded using three-dimensional particle tracking velocimetry. Copepods swimming in still water display an intermittent behaviour characterized by a high probability of small velocity increments, and by stretched exponential tails. Low values arise from their steady cruising behaviour while heavy tails result from frequent relocation jumps. In turbulence, we show that at short time scales, the intermittency signature of active copepods clearly differs from that of the underlying flow, and reflects the frequent relocation jumps displayed by these small animals. Despite these differences, we show that copepods swimming in still and turbulent flow belong to the same intermittency class that can be modelled by a log-stable model with non-analytical cumulant generating function. Intermittency in swimming behaviour and relocation jumps may enable copepods to display oriented, collective motion under strong hydrodynamic conditions and thus, may contribute to the formation of zooplankton patches in energetic environments.

Unsteady propulsion by an intermittent swimming gait

Science.gov (United States)

Akoz, Emre; Moored, Keith W.

2018-01-01

Inviscid computational results are presented on a self-propelled swimmer modeled as a virtual body combined with a two-dimensional hydrofoil pitching intermittently about its leading edge. Lighthill (1971) originally proposed that this burst-and-coast behavior can save fish energy during swimming by taking advantage of the viscous Bone-Lighthill boundary layer thinning mechanism. Here, an additional inviscid Garrick mechanism is discovered that allows swimmers to control the ratio of their added mass thrust-producing forces to their circulatory drag-inducing forces by decreasing their duty cycle, DC, of locomotion. This mechanism can save intermittent swimmers as much as 60% of the energy it takes to swim continuously at the same speed. The inviscid energy savings are shown to increase with increasing amplitude of motion, increase with decreasing Lighthill number, Li, and switch to an energetic cost above continuous swimming for sufficiently low DC. Intermittent swimmers are observed to shed four vortices per cycle that form into groups that are self-similar with the DC. In addition, previous thrust and power scaling laws of continuous self-propelled swimming are further generalized to include intermittent swimming. The key is that by averaging the thrust and power coefficients over only the bursting period then the intermittent problem can be transformed into a continuous one. Furthermore, the intermittent thrust and power scaling relations are extended to predict the mean speed and cost of transport of swimmers. By tuning a few coefficients with a handful of simulations these self-propelled relations can become predictive. In the current study, the mean speed and cost of transport are predicted to within 3% and 18% of their full-scale values by using these relations.

Biochemical systems identification by a random drift particle swarm optimization approach

Science.gov (United States)

2014-01-01

Background Finding an efficient method to solve the parameter estimation problem (inverse problem) for nonlinear biochemical dynamical systems could help promote the functional understanding at the system level for signalling pathways. The problem is stated as a data-driven nonlinear regression problem, which is converted into a nonlinear programming problem with many nonlinear differential and algebraic constraints. Due to the typical ill conditioning and multimodality nature of the problem, it is in general difficult for gradient-based local optimization methods to obtain satisfactory solutions. To surmount this limitation, many stochastic optimization methods have been employed to find the global solution of the problem. Results This paper presents an effective search strategy for a particle swarm optimization (PSO) algorithm that enhances the ability of the algorithm for estimating the parameters of complex dynamic biochemical pathways. The proposed algorithm is a new variant of random drift particle swarm optimization (RDPSO), which is used to solve the above mentioned inverse problem and compared with other well known stochastic optimization methods. Two case studies on estimating the parameters of two nonlinear biochemical dynamic models have been taken as benchmarks, under both the noise-free and noisy simulation data scenarios. Conclusions The experimental results show that the novel variant of RDPSO algorithm is able to successfully solve the problem and obtain solutions of better quality than other global optimization methods used for finding the solution to the inverse problems in this study. PMID:25078435

Lotka-Volterra system in a random environment

Science.gov (United States)

Dimentberg, Mikhail F.

2002-03-01

Classical Lotka-Volterra (LV) model for oscillatory behavior of population sizes of two interacting species (predator-prey or parasite-host pairs) is conservative. This may imply unrealistically high sensitivity of the system's behavior to environmental variations. Thus, a generalized LV model is considered with the equation for preys' reproduction containing the following additional terms: quadratic ``damping'' term that accounts for interspecies competition, and term with white-noise random variations of the preys' reproduction factor that simulates the environmental variations. An exact solution is obtained for the corresponding Fokker-Planck-Kolmogorov equation for stationary probability densities (PDF's) of the population sizes. It shows that both population sizes are independent γ-distributed stationary random processes. Increasing level of the environmental variations does not lead to extinction of the populations. However it may lead to an intermittent behavior, whereby one or both population sizes experience very rare and violent short pulses or outbreaks while remaining on a very low level most of the time. This intermittency is described analytically by direct use of the solutions for the PDF's as well as by applying theory of excursions of random functions and by predicting PDF of peaks in the predators' population size.

Storage of intermittent energies. From self-consumption to huge photovoltaic power plants

International Nuclear Information System (INIS)

Perrin, Marion; Martin, Nicolas

2013-01-01

Power grids are evolving rapidly due to an increased use of decentralized power units, mostly based on intermittent renewable energy resources and due also to new ways of consuming energy (e.g. electrical vehicles). In the same time, the performance increase of new technologies such as telecommunications and storage systems could provide solutions for optimizing the electrical system. In this context, we are more and more talking about the 'smart-grids concept' because in parallel to the power interconnection, we also create communication networks which allow knowing in real time the status of the power grid, and so that the power flows can be controlled in an optimal way. In this article, we investigate challenges and opportunities for managing intermittent energy sources by using energy storage systems, from the consumer level to the grid operator. First we describe how the feed-in tariff could evolve in order to improve grid integration of large solar plants. We showed that behind the constraints due to the coupling of the power plants with a storage system, we could imagine lots of opportunities to diversify the business model. Then we evaluate the medium size PV with storage installation at the community level. For this purpose, we describe the local problems induced by the PV integration before proposing new ways to manage these systems. Finally, the self-consumption business model is investigated in terms of performance for the consumer and for the grid operator. (authors)

Efficient 3D porous microstructure reconstruction via Gaussian random field and hybrid optimization.

Science.gov (United States)

Jiang, Z; Chen, W; Burkhart, C

2013-11-01

Obtaining an accurate three-dimensional (3D) structure of a porous microstructure is important for assessing the material properties based on finite element analysis. Whereas directly obtaining 3D images of the microstructure is impractical under many circumstances, two sets of methods have been developed in literature to generate (reconstruct) 3D microstructure from its 2D images: one characterizes the microstructure based on certain statistical descriptors, typically two-point correlation function and cluster correlation function, and then performs an optimization process to build a 3D structure that matches those statistical descriptors; the other method models the microstructure using stochastic models like a Gaussian random field and generates a 3D structure directly from the function. The former obtains a relatively accurate 3D microstructure, but computationally the optimization process can be very intensive, especially for problems with large image size; the latter generates a 3D microstructure quickly but sacrifices the accuracy due to issues in numerical implementations. A hybrid optimization approach of modelling the 3D porous microstructure of random isotropic two-phase materials is proposed in this paper, which combines the two sets of methods and hence maintains the accuracy of the correlation-based method with improved efficiency. The proposed technique is verified for 3D reconstructions based on silica polymer composite images with different volume fractions. A comparison of the reconstructed microstructures and the optimization histories for both the original correlation-based method and our hybrid approach demonstrates the improved efficiency of the approach. © 2013 The Authors Journal of Microscopy © 2013 Royal Microscopical Society.

Which factors make clean intermittent (self) catheterisation successful?

NARCIS (Netherlands)

Cobussen-Boekhorst, H.; Beekman, J.; Wijlick, E. van; Schaafstra, J.; Kuppevelt, D. van; Heesakkers, J.P.

2016-01-01

AIMS AND OBJECTIVES: To explore which factors determine successful intermittent catheterisation. BACKGROUND: Intermittent catheterisation is a safe, effective treatment and is associated with improved quality of life, although negative issues are reported. Factors which determine adherence are

A randomized double-blind crossover comparison of continuous and intermittent subcutaneous administration of opioid for cancer pain.

Science.gov (United States)

Watanabe, Sharon; Pereira, Jose; Tarumi, Yoko; Hanson, John; Bruera, Eduardo

2008-05-01

ABSTRACT Although the preferred route of opioid administration is oral, patients with cancer often require an alternative route. Options include continuous subcutaneous infusion (CSCI) or regularly scheduled intermittent subcutaneous injections (ISCI). CSCI maintains steady drug levels, theoretically avoiding the "bolus effect" of nausea and sedation immediately post-dose, and breakthrough pain prior to the next dose. However, portable infusion pumps can be costly to use. The Edmonton Injector is an inexpensive portable device for ISCI. CSCI and ISCI have not been directly compared. The objective of this trial was to compare CSCI and ISCI of opioid for treatment of cancer pain. Patients were recruited from two tertiary palliative care units. Eligibility criteria included stable cancer pain requiring opioid therapy, need for parenteral route, and normal cognition. Patients were randomly assigned to receive opioid by CSCI by portable pump or ISCI by Edmonton Injector for 48 hours, followed by crossover to the alternative modality for 48 hours. During each phase, placebo was administered by the alternative modality. The study was closed after 12 patients were entered, due to slow accrual. Eleven patients completed the study. There were no differences between CSCI and ISCI in mean visual analogue score (VAS) for pain, nausea or drowsiness; categorical rating score of pain; number of breakthrough opioid doses per day; global rating of treatment effectiveness; or adverse effects. In all cases, patients and investigators expressed no preference for one modality over another. Further research is required to confirm that opioid administration by CSCI and ISCI provide similar analgesic and adverse effects.

Effects of Intermittent Fasting, Caloric Restriction, and Ramadan Intermittent Fasting on Cognitive Performance at Rest and During Exercise in Adults.

Science.gov (United States)

Cherif, Anissa; Roelands, Bart; Meeusen, Romain; Chamari, Karim

2016-01-01

The aim of this review was to highlight the potent effects of intermittent fasting on the cognitive performance of athletes at rest and during exercise. Exercise interacts with dietary factors and has a positive effect on brain functioning. Furthermore, physical activity and exercise can favorably influence brain plasticity. Mounting evidence indicates that exercise, in combination with diet, affects the management of energy metabolism and synaptic plasticity by affecting molecular mechanisms through brain-derived neurotrophic factor, an essential neurotrophin that acts at the interface of metabolism and plasticity. The literature has also shown that certain aspects of physical performance and mental health, such as coping and decision-making strategies, can be negatively affected by daylight fasting. However, there are several types of intermittent fasting. These include caloric restriction, which is distinct from fasting and allows subjects to drink water ad libitum while consuming a very low-calorie food intake. Another type is Ramadan intermittent fasting, which is a religious practice of Islam, where healthy adult Muslims do not eat or drink during daylight hours for 1 month. Other religious practices in Islam (Sunna) also encourage Muslims to practice intermittent fasting outside the month of Ramadan. Several cross-sectional and longitudinal studies have shown that intermittent fasting has crucial effects on physical and intellectual performance by affecting various aspects of bodily physiology and biochemistry that could be important for athletic success. Moreover, recent findings revealed that immunological variables are also involved in cognitive functioning and that intermittent fasting might impact the relationship between cytokine expression in the brain and cognitive deficits, including memory deficits.

Exercise attenuates intermittent hypoxia-induced cardiac fibrosis associated with sodium-hydrogen exchanger-1 in rats

Directory of Open Access Journals (Sweden)

Tsung-I Chen

2016-10-01

Full Text Available Purpose: To investigate the role of sodium–hydrogen exchanger-1 (NHE-1 and exercise training on intermittent hypoxia-induced cardiac fibrosis in obstructive sleep apnea (OSA, using an animal model mimicking the intermittent hypoxia of OSA. Methods: Eight-week-old male Sprague–Dawley rats were randomly assigned to control (CON, intermittent hypoxia (IH, exercise (EXE or IH combined with exercise (IHEXE groups. These groups were randomly assigned to subgroups receiving either a vehicle or the NHE-1 inhibitor cariporide. The EXE and IHEXE rats underwent exercise training on an animal treadmill for 10 weeks (5 days/week, 60 minutes/day, 24–30 m/minute, 2–10% grade. The IH and IHEXE rats were exposed to 14 days of IH (30 seconds of hypoxia - nadir of 2-6% O2 - followed by 45 seconds of normoxia for 8 hours/day. At the end of 10 weeks, rats were sacrificed and then hearts were removed to determine the myocardial levels of fibrosis index, oxidative stress, antioxidant capacity and NHE-1 activation. Results: Compared to the CON rats, IH induced higher cardiac fibrosis, lower myocardial catalase and superoxidative dismutase activities, higher myocardial lipid and protein peroxidation and higher NHE-1 activation (p < 0.05 for each, which were all abolished by cariporide. Compared to the IH rats, lower cardiac fibrosis, higher myocardial antioxidant capacity, lower myocardial lipid and protein peroxidation and lower NHE-1 activation were found in the IHEXE rats (p < 0.05 for each. Conclusion: IH-induced cardiac fibrosis was associated with NHE-1 hyperactivity. However, exercise training and cariporide exerted an inhibitory effect to prevent myocardial NHE-1 hyperactivity, which contributed to reduced IH-induced cardiac fibrosis. Therefore, NHE-1 plays a critical role in the effect of exercise on IH-induced increased cardiac fibrosis.

Photonic integrated circuits unveil crisis-induced intermittency.

Science.gov (United States)

Karsaklian Dal Bosco, Andreas; Akizawa, Yasuhiro; Kanno, Kazutaka; Uchida, Atsushi; Harayama, Takahisa; Yoshimura, Kazuyuki

2016-09-19

We experimentally investigate an intermittent route to chaos in a photonic integrated circuit consisting of a semiconductor laser with time-delayed optical feedback from a short external cavity. The transition from a period-doubling dynamics to a fully-developed chaos reveals a stage intermittently exhibiting these two dynamics. We unveil the bifurcation mechanism underlying this route to chaos by using the Lang-Kobayashi model and demonstrate that the process is based on a phenomenon of attractor expansion initiated by a particular distribution of the local Lyapunov exponents. We emphasize on the crucial importance of the distribution of the steady-state solutions introduced by the time-delayed feedback on the existence of this intermittent dynamics.

Chaos synchronization based on intermittent state observer

Institute of Scientific and Technical Information of China (English)

Li Guo-Hui; Zhou Shi-Ping; Xu De-Ming

2004-01-01

This paper describes the method of synchronizing slave to the master trajectory using an intermittent state observer by constructing a synchronizer which drives the response system globally tracing the driving system asymptotically. It has been shown from the theory of synchronization error-analysis that a satisfactory result of chaos synchronization is expected under an appropriate intermittent period and state observer. Compared with continuous control method,the proposed intermittent method can target the desired orbit more efficiently. The application of the method is demonstrated on the hyperchaotic Rossler systems. Numerical simulations show that the length of the synchronization interval rs is of crucial importance for our scheme, and the method is robust with respect to parameter mismatch.

Controls on streamflow intermittence in the Colorado Front Range

Science.gov (United States)

Kampf, S. K.; Puntenney, K.; Martin, C.; Weber, R.; Gerlich, J.; Hammond, J. C.; Lefsky, M. A.

2017-12-01

Intermittent streams comprise more than 60% of the channel length in semiarid northern Colorado, yet little is known about their flow magnitude and timing. We used field surveys, stream sensors, and remote sensing to quantify spatial and temporal patterns of streamflow intermittence in the Cache la Poudre basin in 2016-2017. To evaluate potential controls on streamflow intermittence, we delineated the drainage area to each monitored point and quantified the catchment's mean precipitation, temperature, snow persistence, slope, aspect, vegetation type, soil type, and bedrock geology. During the period of study, most streams below 2500 m elevation and drainage areas >1 km2 had perennial flow, whereas nearly all streams with drainage areas <1 km2 had intermittent flow. For the high elevation intermittent streams, stream locations often differed substantially from the locations mapped in standard GIS data products. Initial analyses have identified no clearly quantifiable controls on flow duration of high elevation streams, but field observations indicate subsurface flow paths are important contributors to surface streams.

Particle swarm optimization with random keys applied to the nuclear reactor reload problem

Energy Technology Data Exchange (ETDEWEB)

Meneses, Anderson Alvarenga de Moura [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Programa de Engenharia Nuclear; Fundacao Educacional de Macae (FUNEMAC), RJ (Brazil). Faculdade Professor Miguel Angelo da Silva Santos; Machado, Marcelo Dornellas; Medeiros, Jose Antonio Carlos Canedo; Schirru, Roberto [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Programa de Engenharia Nuclear]. E-mails: ameneses@con.ufrj.br; marcelo@lmp.ufrj.br; canedo@lmp.ufrj.br; schirru@lmp.ufrj.br

2007-07-01

In 1995, Kennedy and Eberhart presented the Particle Swarm Optimization (PSO), an Artificial Intelligence metaheuristic technique to optimize non-linear continuous functions. The concept of Swarm Intelligence is based on the socials aspects of intelligence, it means, the ability of individuals to learn with their own experience in a group as well as to take advantage of the performance of other individuals. Some PSO models for discrete search spaces have been developed for combinatorial optimization, although none of them presented satisfactory results to optimize a combinatorial problem as the nuclear reactor fuel reloading problem (NRFRP). In this sense, we developed the Particle Swarm Optimization with Random Keys (PSORK) in previous research to solve Combinatorial Problems. Experiences demonstrated that PSORK performed comparable to or better than other techniques. Thus, PSORK metaheuristic is being applied in optimization studies of the NRFRP for Angra 1 Nuclear Power Plant. Results will be compared with Genetic Algorithms and the manual method provided by a specialist. In this experience, the problem is being modeled for an eight-core symmetry and three-dimensional geometry, aiming at the minimization of the Nuclear Enthalpy Power Peaking Factor as well as the maximization of the cycle length. (author)

Particle swarm optimization with random keys applied to the nuclear reactor reload problem

International Nuclear Information System (INIS)

Meneses, Anderson Alvarenga de Moura; Fundacao Educacional de Macae; Machado, Marcelo Dornellas; Medeiros, Jose Antonio Carlos Canedo; Schirru, Roberto

2007-01-01

In 1995, Kennedy and Eberhart presented the Particle Swarm Optimization (PSO), an Artificial Intelligence metaheuristic technique to optimize non-linear continuous functions. The concept of Swarm Intelligence is based on the socials aspects of intelligence, it means, the ability of individuals to learn with their own experience in a group as well as to take advantage of the performance of other individuals. Some PSO models for discrete search spaces have been developed for combinatorial optimization, although none of them presented satisfactory results to optimize a combinatorial problem as the nuclear reactor fuel reloading problem (NRFRP). In this sense, we developed the Particle Swarm Optimization with Random Keys (PSORK) in previous research to solve Combinatorial Problems. Experiences demonstrated that PSORK performed comparable to or better than other techniques. Thus, PSORK metaheuristic is being applied in optimization studies of the NRFRP for Angra 1 Nuclear Power Plant. Results will be compared with Genetic Algorithms and the manual method provided by a specialist. In this experience, the problem is being modeled for an eight-core symmetry and three-dimensional geometry, aiming at the minimization of the Nuclear Enthalpy Power Peaking Factor as well as the maximization of the cycle length. (author)

Remote optimal state estimation over communication channels with random delays

KAUST Repository

Mahmoud, Magdi S.

2014-01-22

This paper considers the optimal estimation of linear systems over unreliable communication channels with random delays. In this work, it is assumed that the system to be estimated is far away from the filter. The observations of the system are capsulized without time stamp and then transmitted to the network node at which the filter is located. The probabilities of time delays are assumed to be known. The event-driven estimation scheme is applied in this paper and the estimate of the states is updated only at each time instant when any measurement arrives. To capture the feature of communication, the system considered is augmented, and the arrived measurements are regarded as the uncertain observations of the augmented system. The corresponding optimal estimation algorithm is proposed and additionally, a numerical simulation represents the performance of this work. © 2014 The authors. Published by Oxford University Press on behalf of the Institute of Mathematics and its Applications. All rights reserved.

Effect of Simulated Intermittent Altitude on the Metabolic and Hematologic Parameters in Streptozotocin Induced Diabetic Rats

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mehdi Faramoushi

2016-04-01

Full Text Available Background & objectives: Type II diabetes is a metabolic disorder accompanied with insulin resistance of the whole body cells and is considered be the fifth cause of death in the world. Adaptation to altitude can lead to tolerance to many diseases. Therefore, the aim of this study was to determine the effect of simulated intermittent altitude on the metabolic and hematologic parameters and liver function in streptozotocin induced diabetic rats. Methods: In the current experimental study, twenty four male Wistar rats weighing 220±20 gr were randomly divided into three groups; normal control group (NC, n=8, diabetic control group (D, n=8 received fat diet for 2 weeks then were injected with streptozotocin (37 mg/kg and diabetic+hypoxia group (D+H, n=8 including diabetic rat exposed to chronic intermittent hypoxia (PiO2≈106 mm Hg, simulated altitude≈3400 m, 14% oxygen for 8 weeks. Diabetic, hematologic and lipid parameters as well as ALT and AST activities were measured in peripheral blood. Results: Our findings showed that intermittent hypoxia significantly decreased serum total cholesterol, LDL ,VLDL and triglyceride in D+H group compared to D group (p<0.05. Serum levels of fasting blood glucose and homeostatic model assessment-insulin resistance HOMA-IR( index and ALT were decreased in D+H group vs. D group p<0.05. Also, hemoglubin and hematocrite level increased in D+H group in comparison to D group p<0.05. No significant difference was detected in red blood cell count in D+H vs. D group. Conclusion: Based on resultant data, it seems that intermittent exposure to hypoxia (simulated to chronic and intermittent lodgement in altitude can be used to control of type 2 diabetes by increasing hemoglobin, decreasing insulin resistance and improving liver function as well as lipid parameters.

Modified meta-heuristics using random mutation for truss topology optimization with static and dynamic constraints

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Vimal J. Savsani

2017-04-01

The static and dynamic responses to the TTO problems are challenging due to its search space, which is implicit, non-convex, non-linear, and often leading to divergence. Modified meta-heuristics are effective optimization methods to handle such problems in actual fact. In this paper, modified versions of Teaching–Learning-Based Optimization (TLBO, Heat Transfer Search (HTS, Water Wave Optimization (WWO, and Passing Vehicle Search (PVS are proposed by integrating the random mutation-based search technique with them. This paper compares the performance of four modified and four basic meta-heuristics to solve discrete TTO problems.

Clinical study of intermittent lock of the temporomandibular joint. Relation to frequency of intermittent lock on clinical examination and magnetic resonance imaging

Energy Technology Data Exchange (ETDEWEB)

Ide, Takashi; Nagai, Itaru; Miyazaki, Akihiro; Yamaguchi, Akira; Kohama, Geniku [Sapporo Medical Univ. (Japan). School of Medicine

2002-03-01

To examine the occurrence of intermittent lock, we investigated the correlation between the frequency of intermittent lock of the temporomandibular joint and magnetic resonance imaging (MRI) findings. The subjects consisted of 25 patients (25 joints) with unilateral intermittent lock who were treated from April 1994 through March 2000 at our department. MRI examination of the joint was performed on the affected side. We divided the patients into two groups: a high-frequency group consisting of 15 patients who had symptoms of intermittent lock every day and a low-frequency group consisting of 10 patients who did not have symptoms every day. The results showed no statistical difference between the two groups in clinical findings such as age, sex, clicking side of the joint, duration of intermittent lock, method of unlocking, muscle pain on palpation, degree of maximal mouth opening, distance between the maxillary and mandibular tooth midline, or the degree of overbite and overjet. However, the two groups differed significantly in the degree of anterior disc displacement as assessed by MRI. (author)

Cluster-randomized study of intermittent preventive treatment for malaria in infants (IPTi in southern Tanzania: evaluation of impact on survival

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Schellenberg Joanna

2011-12-01

Full Text Available Abstract Background Intermittent Preventive Treatment for malaria control in infants (IPTi consists of the administration of a treatment dose of an anti-malarial drug, usually sulphadoxine-pyrimethamine, at scheduled intervals, regardless of the presence of Plasmodium falciparum infection. A pooled analysis of individually randomized trials reported that IPTi reduced clinical episodes by 30%. This study evaluated the effect of IPTi on child survival in the context of a five-district implementation project in southern Tanzania. [Trial registration: clinical trials.gov NCT00152204]. Methods After baseline household and health facility surveys in 2004, five districts comprising 24 divisions were randomly assigned either to receive IPTi (n = 12 or not (n = 12. Implementation started in March 2005, led by routine health services with support from the research team. In 2007, a large household survey was undertaken to assess the impact of IPTi on survival in infants aged two-11 months through birth history interviews with all women aged 13-49 years. The analysis is based on an "intention-to-treat" ecological design, with survival outcomes analysed according to the cluster in which the mothers lived. Results Survival in infants aged two-11 months was comparable in IPTi and comparison areas at baseline. In intervention areas in 2007, 48% of children aged 12-23 months had documented evidence of receiving three doses of IPTi, compared to 2% in comparison areas (P P = 0.31. Conclusion The lack of evidence of an effect of IPTi on survival could be a false negative result due to a lack of power or imbalance of unmeasured confounders. Alternatively, there could be no mortality impact of IPTi due to low coverage, late administration, drug resistance, decreased malaria transmission or improvements in vector control and case management. This study raises important questions for programme evaluation design.

[Comparison of the effect of continuous and intermittent physical loading in type I diabetics].

Science.gov (United States)

Rusavý, Z; Lacigová, S; Holecek, T; Srámek, V; Novák, I; Tĕsínský, P

1994-07-01

In order to evaluate the optimal mode of physical loads the authors examined 19 diabetics type I without secondary complications. On the second day of an educational-rehabilitation camp the authors subjected the patients to a continuous load-a 40-minute endurance run at a heart rate equal to 60% of the maximal oxygen requirement. On the fifth day an intermittent load with a maximal intensity--training of 4 x 10 minutes with 5-minute intervals was administered. At the onset, during the 20th and 40th minute of the load the titrable acidity, lactate and blood sugar level were assessed. The intermittent load led already after 20 minutes to marked acidosis (titrable acidity = 12) which did not increase after 40 minutes of the load. The authors recorded a statistically significant rise of the lactate level (4.57 mmol/l) which after 40 minutes of the load rose further to 12.3 mmol/l, as compared with values of titrable acidity during the 20th and 40th minute (0.44 and 1.14) and lactate during the 20th and 40th minute (4.57 and 3.86 mmol/l) during a continuous load. After evaluation by the test of linear correlation it appears with regard to the stability of the blood sugar level during a load that an intermittent load is more favourable. The drop of the blood sugar level in time during a continuous load was at the 1 level of significance, in intermittent loads at the 5% of significance. Both types of loads did not lead to hypoglycaemia or other complications and thus both can be used in diabetics type I.

Guided randomness in optimization

CERN Document Server

Clerc, Maurice

2015-01-01

The performance of an algorithm used depends on the GNA. This book focuses on the comparison of optimizers, it defines a stress-outcome approach which can be derived all the classic criteria (median, average, etc.) and other more sophisticated.   Source-codes used for the examples are also presented, this allows a reflection on the ""superfluous chance,"" succinctly explaining why and how the stochastic aspect of optimization could be avoided in some cases.

Safety and adherence to intermittent pre-exposure prophylaxis (PrEP for HIV-1 in African men who have sex with men and female sex workers.

Directory of Open Access Journals (Sweden)

Gaudensia Mutua

Full Text Available Little is known about safety of and adherence to intermittent HIV PrEP regimens, which may be more feasible than daily dosing in some settings. We present safety and adherence data from the first trial of an intermittent PrEP regimen among Kenyan men who have sex with men (MSM and female sex workers (FSW.MSM and FSW were randomized to daily oral FTC/TDF or placebo, or intermittent (Monday, Friday and within 2 hours after sex, not to exceed one dose per day oral FTC/TDF or placebo in a 2:1:2:1 ratio; volunteers were followed monthly for 4 months. Adherence was assessed with the medication event monitoring system (MEMS. Sexual activity data were collected via daily text message (SMS queries and timeline followback interviews with a one-month recall period. Sixty-seven men and 5 women were randomized into the study. Safety was similar among all groups. Median MEMS adherence rates were 83% [IQR: 63-92] for daily dosing and 55% [IQR:28-78] for fixed intermittent dosing (p = 0.003, while adherence to any post-coital doses was 26% [IQR:14-50]. SMS response rates were low, which may have impaired measurement of post-coital dosing adherence. Acceptability of PrEP was high, regardless of dosing regimen.Adherence to intermittent dosing regimens, fixed doses, and in particular coitally-dependent doses, may be more difficult than adherence to daily dosing. However, intermittent dosing may still be appropriate for PrEP if intracellular drug levels, which correlate with prevention of HIV acquisition, can be attained with less than daily dosing and if barriers to adherence can be addressed. Additional drug level data, qualitative data on adherence barriers, and better methods to measure sexual activity are necessary to determine whether adherence to post-coital PrEP could be comparable to more standard regimens.ClinicalTrials.gov NCT00971230.

Observation of intermittency in gene expression on cDNA microarrays

CERN Document Server

Peterson, L E

2002-01-01

We used scaled factorial moments to search for intermittency in the log expression ratios (LERs) for thousands of genes spotted on cDNA microarrays (gene chips). Results indicate varying levels of intermittency in gene expression. The observation of intermittency in the data analyzed provides a complimentary handle on moderately expressed genes, generally not tackled by conventional techniques.

Robust video watermarking via optimization algorithm for quantization of pseudo-random semi-global statistics

Science.gov (United States)

Kucukgoz, Mehmet; Harmanci, Oztan; Mihcak, Mehmet K.; Venkatesan, Ramarathnam

2005-03-01

In this paper, we propose a novel semi-blind video watermarking scheme, where we use pseudo-random robust semi-global features of video in the three dimensional wavelet transform domain. We design the watermark sequence via solving an optimization problem, such that the features of the mark-embedded video are the quantized versions of the features of the original video. The exact realizations of the algorithmic parameters are chosen pseudo-randomly via a secure pseudo-random number generator, whose seed is the secret key, that is known (resp. unknown) by the embedder and the receiver (resp. by the public). We experimentally show the robustness of our algorithm against several attacks, such as conventional signal processing modifications and adversarial estimation attacks.

Chronic intermittent fasting improves the survival following large myocardial ischemia by activation of BDNF/VEGF/PI3K signaling pathway.

Science.gov (United States)

Katare, Rajesh G; Kakinuma, Yoshihiko; Arikawa, Mikihiko; Yamasaki, Fumiyasu; Sato, Takayuki

2009-03-01

Chronic heart failure (CHF) is the major cause of death in the developed countries. Calorie restriction is known to improve the recovery in these patients; however, the exact mechanism behind this protective effect is unknown. Here we demonstrate the activation of cell survival PI3kinase/Akt and VEGF pathway as the mechanism behind the protection induced by intermittent fasting in a rat model of established chronic myocardial ischemia (MI). Chronic MI was induced in rats by occlusion of the left coronary artery. Two weeks later, the rats were randomly assigned to a normal feeding group (MI-NF) and an alternate-day feeding group (MI-IF). After 6 weeks of observation, we evaluated the effect of intermittent fasting on cellular and ventricular remodeling and long-term survival after CHF. Compared with the normally fed group, intermittent fasting markedly improved the survival of rats with CHF (88.5% versus 23% survival, Pfasted hearts. Immunohistochemical studies confirmed increased capillary density (Pfasting also upregulated the expression of other anti-apoptotic factors such as Akt and Bcl-2 and reduced the TUNEL positive apoptotic nuclei in the border zone. Chronic intermittent fasting markedly improves the long-term survival after CHF by activation through its pro-angiogenic, anti-apoptotic and anti-remodeling effects.

Intermittent sequential pneumatic compression of the legs and thromboembolism-deterrent stockings in the prevention of postoperative deep venous thrombosis

International Nuclear Information System (INIS)

Nicolaides, A.N.; Miles, C.; Hoare, M.; Jury, P.; Helmis, E.; Venniker, R.

1983-01-01

One hundred fifty patients over the age of 30 who had undergone major abdominal operations were stratified according to the risk of deep venous thrombosis and randomized into three groups to receive different prophylactic regimens: group A, electrical calf stimulation; group B, low-dose subcutaneous heparin; group C, intermittent sequential compression and thromboembolism-deterrent (TED) stockings. All the patients were scanned with the 125 I-fibrinogen test for the whole stay in hospital. The incidence of 125 I-fibrinogen detected deep venous thrombi was 18% in group A, 9% in group B, and 4% in group C. The results indicate that the regimen of intermittent sequential compression and TED stockings is as effective as low-dose subcutaneous heparin. Electrical calf stimulation is less effective

Modeling and sizing a Storage System coupled with intermittent renewable power generation

International Nuclear Information System (INIS)

Bridier, Laurent

2016-01-01

This thesis aims at presenting an optimal management and sizing of an Energy Storage System (ESS) paired up with Intermittent Renewable Energy Sources (IReN). Firstly, we developed a technical-economic model of the system which is associated with three typical scenarios of utility grid power supply: hourly smoothing based on a one-day-ahead forecast (S1), guaranteed power supply (S2) and combined scenarios (S3). This model takes the form of a large-scale non-linear optimization program. Secondly, four heuristic strategies are assessed and lead to an optimized management of the power output with storage according to the reliability, productivity, efficiency and profitability criteria. This ESS optimized management is called 'Adaptive Storage Operation' (ASO). When compared to a mixed integer linear program (MILP), this optimized operation that is practicable under operational conditions gives rapidly near-optimal results. Finally, we use the ASO in ESS optimal sizing for each renewable energy: wind, wave and solar (PV). We determine the minimal sizing that complies with each scenario, by inferring the failure rate, the viable feed-in tariff of the energy, and the corresponding compliant, lost or missing energies. We also perform sensitivity analysis which highlights the importance of the ESS efficiency and of the forecasting accuracy and the strong influence of the hybridization of renewables on ESS technical-economic sizing. (author) [fr

Intermittent Testicular Torsion

African Journals Online (AJOL)

2017-06-02

Jun 2, 2017 ... had prior episodes of testicular pain, suggesting that they may have had intermittent torsion before .... None of the patients had antecedent history of sexual exposure, fever, or urinary tract infection .... torsion of the spermatic cord portends an increased risk of acute testicular infarction. J Urol 2008;180 4 ...

Intermittent metabolic switching, neuroplasticity and brain health

Science.gov (United States)

Mattson, Mark P.; Moehl, Keelin; Ghena, Nathaniel; Schmaedick, Maggie; Cheng, Aiwu

2018-01-01

During evolution, individuals whose brains and bodies functioned well in a fasted state were successful in acquiring food, enabling their survival and reproduction. With fasting and extended exercise, liver glycogen stores are depleted and ketones are produced from adipose-cell-derived fatty acids. This metabolic switch in cellular fuel source is accompanied by cellular and molecular adaptations of neural networks in the brain that enhance their functionality and bolster their resistance to stress, injury and disease. Here, we consider how intermittent metabolic switching, repeating cycles of a metabolic challenge that induces ketosis (fasting and/or exercise) followed by a recovery period (eating, resting and sleeping), may optimize brain function and resilience throughout the lifespan, with a focus on the neuronal circuits involved in cognition and mood. Such metabolic switching impacts multiple signalling pathways that promote neuroplasticity and resistance of the brain to injury and disease. PMID:29321682

Effect of Intermittent Hypercapnia on Respiratory Control in Rat Pups

Science.gov (United States)

Steggerda, Justin A.; Mayer, Catherine A.; Martin, Richard J.; Wilson, Christopher G.

2010-01-01

Preterm infants are subject to fluctuations in blood gas status associated with immature respiratory control. Intermittent hypoxia during early postnatal life has been shown to increase chemoreceptor sensitivity and destabilize the breathing pattern; however, intermittent hypercapnia remains poorly studied. Therefore, to test the hypothesis that intermittent hypercapnia results in altered respiratory control, we examined the effects of daily exposure to intermittent hypercapnia on the ventilatory response to subsequent hypercapnic and hypoxic exposure in neonatal rat pups. Exposure cycles consisted of 5 min of intermittent hypercapnia (5% CO2, 21% O2, balance N2) followed by 10 min of normoxia. Rat pups were exposed to 18 exposure cycles each day for 1 week, from postnatal day 7 to 14. We analyzed diaphragm electromyograms (EMGs) from pups exposed to subsequent acute hypercapnic (5% CO2) and hypoxic (12% O2) challenges. In response to a subsequent hypercapnia challenge, there was no significant difference in the ventilatory response between control and intermittent hypercapnia-exposed groups. In contrast, intermittent hypercapnia-exposed rat pups showed an enhanced ventilatory response to hypoxic challenge with an increase in minute EMG to 118 ± 14% of baseline versus 107 ± 13% for control pups (p < 0.05). We speculate that prior hypercapnic exposure may increase peripheral chemoreceptor response to subsequent hypoxic exposures and result in perturbed neonatal respiratory control. PMID:19752577

Losartan reduces the immediate and sustained increases in muscle sympathetic nerve activity after hyperacute intermittent hypoxia.

Science.gov (United States)

Jouett, Noah P; Moralez, Gilbert; Raven, Peter B; Smith, Michael L

2017-04-01

Obstructive sleep apnea (OSA) is characterized by intermittent hypoxemia, which produces elevations in sympathetic nerve activity (SNA) and associated hypertension in experimental models that persist beyond the initial exposure. We tested the hypotheses that angiotensin receptor blockade in humans using losartan attenuates the immediate and immediately persistent increases in 1 ) SNA discharge and 2 ) mean arterial pressure (MAP) after hyperacute intermittent hypoxia training (IHT) using a randomized, placebo-controlled, repeated-measures experimental design. We measured ECG and photoplethysmographic arterial pressure in nine healthy human subjects, while muscle SNA (MSNA) was recorded in seven subjects using microneurography. Subjects were exposed to a series of hypoxic apneas in which they inhaled two to three breaths of nitrogen, followed by a 20-s apnea and 40 s of room air breathing every minute for 20 min. Hyperacute IHT produced substantial and persistent elevations in MSNA burst frequency (baseline: 15.3 ± 1.8, IHT: 24 ± 1.5, post-IHT 20.0 ± 1.3 bursts/min, all P 0.70). This investigation confirms the role of angiotensin II type 1a receptors in the immediate and persistent sympathoexcitatory and pressor responses to IHT. NEW & NOTEWORTHY This study demonstrates for the first time in humans that losartan, an angiotensin receptor blocker (ARB), abrogates the acute and immediately persistent increases in muscle sympathetic nerve activity and arterial pressure in response to acute intermittent hypoxia. This investigation, along with others, provides important beginning translational evidence for using ARBs in treatment of the intermittent hypoxia observed in obstructive sleep apnea patients. Copyright © 2017 the American Physiological Society.

Intermittent Hypoxia Causes Inflammation and Injury to Human Adult Cardiac Myocytes.

Science.gov (United States)

Wu, Jing; Stefaniak, Joanna; Hafner, Christina; Schramel, Johannes Peter; Kaun, Christoph; Wojta, Johann; Ullrich, Roman; Tretter, Verena Eva; Markstaller, Klaus; Klein, Klaus Ulrich

2016-02-01

Intermittent hypoxia may occur in a number of clinical scenarios, including interruption of myocardial blood flow or breathing disorders such as obstructive sleep apnea. Although intermittent hypoxia has been linked to cardiovascular and cerebrovascular disease, the effect of intermittent hypoxia on the human heart is not fully understood. Therefore, in the present study, we compared the cellular responses of cultured human adult cardiac myocytes (HACMs) exposed to intermittent hypoxia and different conditions of continuous hypoxia and normoxia. HACMs were exposed to intermittent hypoxia (0%-21% O2), constant mild hypoxia (10% O2), constant severe hypoxia (0% O2), or constant normoxia (21% O2), using a novel cell culture bioreactor with gas-permeable membranes. Cell proliferation, lactate dehydrogenase release, vascular endothelial growth factor release, and cytokine (interleukin [IL] and macrophage migration inhibitory factor) release were assessed at baseline and after 8, 24, and 72 hours of exposure. A signal transduction pathway finder array was performed to determine the changes in gene expression. In comparison with constant normoxia and constant mild hypoxia, intermittent hypoxia induced earlier and greater inflammatory response and extent of cell injury as evidenced by lower cell numbers and higher lactate dehydrogenase, vascular endothelial growth factor, and proinflammatory cytokine (IL-1β, IL-6, IL-8, and macrophage migration inhibitory factor) release. Constant severe hypoxia showed more detrimental effects on HACMs at later time points. Pathway analysis demonstrated that intermittent hypoxia primarily altered gene expression in oxidative stress, Wnt, Notch, and hypoxia pathways. Intermittent and constant severe hypoxia, but not constant mild hypoxia or normoxia, induced inflammation and cell injury in HACMs. Cell injury occurred earliest and was greatest after intermittent hypoxia exposure. Our in vitro findings suggest that intermittent hypoxia

Intermittent, Non Cyclic Severe Mechanical Aortic Valve Regurgitation

Science.gov (United States)

Choi, Jong Hyun; Song, Seunghwan; Lee, Myung-Yong

2013-01-01

Mechanical aortic prosthesis dysfunction can result from thrombosis or pannus formation. We describe an unusual case of intermittent, non cyclic mechanical aortic prosthesis dysfunction due to pannus formation with thrombus in the absence of systolic restriction of disk excursion, that presented with intermittent severe aortic regurgitation. PMID:24459568

Intermittent fasting: a "new" historical strategy for controlling seizures?

Science.gov (United States)

Hartman, Adam L; Rubenstein, James E; Kossoff, Eric H

2013-05-01

In antiquity, fasting was a treatment for epilepsy and a rationale for the ketogenic diet (KD). Preclinical data indicate the KD and intermittent fasting do not share identical anticonvulsant mechanisms. We implemented an intermittent fasting regimen in six children with an incomplete response to a KD. Three patients adhered to the combined intermittent fasting/KD regimen for 2 months and four had transient improvement in seizure control, albeit with some hunger-related adverse reactions. Copyright © 2012 Elsevier B.V. All rights reserved.

Beetroot Juice Supplementation Improves High-Intensity Intermittent Type Exercise Performance in Trained Soccer Players

Directory of Open Access Journals (Sweden)

Jean Nyakayiru

2017-03-01

Full Text Available It has been shown that nitrate supplementation can enhance endurance exercise performance. Recent work suggests that nitrate ingestion can also increase intermittent type exercise performance in recreational athletes. We hypothesized that six days of nitrate supplementation can improve high-intensity intermittent type exercise performance in trained soccer players. Thirty-two male soccer players (age: 23 ± 1 years, height: 181 ± 1 m, weight: 77 ± 1 kg, playing experience: 15.2 ± 0.5 years, playing in the first team of a 2nd or 3rd Dutch amateur league club participated in this randomized, double-blind cross-over study. All subjects participated in two test days in which high-intensity intermittent running performance was assessed using the Yo-Yo IR1 test. Subjects ingested nitrate-rich (140 mL; ~800 mg nitrate/day; BR or a nitrate-depleted beetroot juice (PLA for six subsequent days, with at least eight days of wash-out between trials. The distance covered during the Yo-Yo IR1 was the primary outcome measure, while heart rate (HR was measured continuously throughout the test, and a single blood and saliva sample were collected just prior to the test. Six days of BR ingestion increased plasma and salivary nitrate and nitrite concentrations in comparison to PLA (p < 0.001, and enhanced Yo-Yo IR1 test performance by 3.4 ± 1.3% (from 1574 ± 47 to 1623 ± 48 m; p = 0.027. Mean HR was lower in the BR (172 ± 2 vs. PLA trial (175 ± 2; p = 0.014. Six days of BR ingestion effectively improves high-intensity intermittent type exercise performance in trained soccer players.

Effect of Intermittent Drying Conditions on Fissuring Percentage and Process Duration of Long and Medium Rough Rice Varieties

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A. Ghasemi

2016-02-01

Full Text Available One of the factors which affect the quality of rice during milling is internal fissures created during and after drying operation. In many industrial countries intermittent drying method is hired to reduce the moisture content of rough rice in order to reduce the drying time and maintain the quality of the final product. A high percentage of rice breakage during milling process, at least in Iran, necessitates performing the intermittent drying process and optimize it for Iranian varieties. In this study, the effect of this method (drying-tempering and continuous drying method (no tempering on fissuring percentage of Hashemi (long grain and Koohsar (medium grain varieties was investigated. The experiments were carried out at constant drying and tempering temperature of 60 °C, drying durations of 20, 40 and 60 min, and tempering durations of 0 (continuous drying, 40, 80, 120, 160, 200, 240 min. The results revealed that the tempering process significantly reduced the drying time and fissured kernels percentage. Moreover, for both varieties it was observed that the rice fissuring decreased significantly by continuing the tempering process until certain durations. Overall, for optimization of intermittent drying process in terms of the considered qualitative parameters, i.e. reducing energy consumption and losses, conducting 160 and 200 min tempering process after 40 min drying was found appropriate for Hashemi and Koohsar varieties, respectively. In addition, according to the higher fissuring for Koohsar (medium grain compared to Hashemi (long grain, it can be concluded that physical properties such as kernel slenderness ratio is effective on its fissuring.

Factors Relevant to Utility Integration of Intermittent Renewable Technologies

Energy Technology Data Exchange (ETDEWEB)

Wan, Y.; Parsons, B.

1993-08-24

This study assesses factors that utilities must address when they integrate intermittent renewable technologies into their power-supply systems; it also reviews the literature in this area and has a bibliography containing more than 350 listings. Three topics are covered: (1) interface (hardware and design-related interconnection), (2) operability/stability, and (3) planning. This study finds that several commonly held perceptions regarding integration of intermittent renewable energy technologies are not valid. Among fmdings of the study are the following: (1) hardware and system design advances have eliminated most concerns about interface, (2) cost penalties have not occurred at low to moderate penetration levels (and high levels am feasible); and (3) intermittent renewable energy technologies can have capacity values. Obstacles still interfering with intermittent renewable technologies are also indentified.

Factors relevant to utility integration of intermittent renewable technologies

Energy Technology Data Exchange (ETDEWEB)

Wan, Yih-huei; Parsons, B.K.

1993-08-01

This study assesses factors that utilities must address when they integrate intermittent renewable technologies into their power-supply systems; it also reviews the literature in this area and has a bibliography containing more than 350 listings. Three topics are covered: (1) interface (hardware and design-related interconnection), (2) operability/stability, and (3) planning. This study finds that several commonly held perceptions regarding integration of intermittent renewable energy technologies are not valid. Among findings of the study are the following: (1) hardware and system design advances have eliminated most concerns about interface; (2) cost penalties have not occurred at low to moderate penetration levels (and high levels are feasible); and (3) intermittent renewable energy technologies can have capacity values. Obstacles still interfering with intermittent renewable technologies are also identified.

Effectiveness of interspinous implant surgery in patients with intermittent neurogenic claudication: a systematic review and meta-analysis

OpenAIRE

Moojen, Wouter A.; Arts, Mark P.; Bartels, Ronald H. M. A.; Jacobs, Wilco C. H.; Peul, Wilco C.

2011-01-01

Introduction Despite an increasing implantation rate of interspinous process distraction (IPD) devices in the treatment of intermittent neurogenic claudication (INC), definitive evidence on the clinical effectiveness of implants is lacking. The main objective of this review was to perform a meta-analysis of all systematic reviews, randomized clinical trials and prospective cohort series to quantify the effectiveness of IPDs and to evaluate the potential side-effects. Methods Data from all stu...

Hierarchy compensation of non-homogeneous intermittent atmospheric turbulence

Science.gov (United States)

Redondo, Jose M.; Mahjoub, Otman B.; Cantalapiedra, Inma R.

2010-05-01

In this work a study both the internal turbulence energy cascade intermittency evaluated from wind speed series in the atmospheric boundary layer, as well as the role of external or forcing intermittency based on the flatness (Vindel et al 2008)is carried out. The degree of intermittency in the stratified ABL flow (Cuxart et al. 2000) can be studied as the deviation, from the linear form, of the absolute scaling exponents of the structure functions as well as generalizing for non-isotropic and non-homogeneous turbulence, even in non-inertial ranges (in the Kolmogorov-Kraichnan sense) where the scaling exponents are not constant. The degree of intermittency, evaluated in the non-local quasi-inertial range, is explained from the variation with scale of the energy transfer as well as the dissipation. The scale to scale transfer and the structure function scaling exponents are calculated and from these the intermittency parametres. The turbulent diffusivity could also be estimated and compared with Richardson's law. Some two point correlations and time lag calculations are used to investigate the time and spatial integral length scales obtained from both Lagrangian and Eulerian correlations and functions, and we compare these results with both theoretical and laboratory data. We develop a theoretical description of how to measure the different levels of intermittency following (Mahjoub et al. 1998, 2000) and the role of locality in higher order exponents of structure function analysis. Vindel J.M., Yague C. and Redondo J.M. (2008) Structure function analysis and intermittency in the ABL. Nonlin. Processes Geophys., 15, 915-929. Cuxart J, Yague C, Morales G, Terradellas E, Orbe J, Calvo J, Fernández A, Soler M R, Infante C, Buenestado P, Espinalt A, Joergensen H E, Rees J M, Vilá J, Redondo J M, Cantalapiedra R and Conangla L (2000): Stable atmospheric boundary-layer experiment in Spain (Sables 98): a report, Boundary-Layer Meteorology 96, 337-370 Mahjoub O

Optimized random phase approximation for the structure of liquid alkali metals as electron-ion plasmas

International Nuclear Information System (INIS)

Senatore, G.; Tosi, M.P.; Trieste Univ.

1981-08-01

The purpose of this letter is to stress that the way towards an unconventional optimized-random-phase-approximation (ORPA) approach to the structure of liquid metals is indicated, and in fact already a good first-order solution for such an approach is provided

Fragmentation under the Scaling Symmetry and Turbulent Cascade with Intermittency

Science.gov (United States)

Gorokhovski, M.

2003-01-01

Fragmentation plays an important role in a variety of physical, chemical, and geological processes. Examples include atomization in sprays, crushing of rocks, explosion and impact of solids, polymer degradation, etc. Although each individual action of fragmentation is a complex process, the number of these elementary actions is large. It is natural to abstract a simple 'effective' scenario of fragmentation and to represent its essential features. One of the models is the fragmentation under the scaling symmetry: each breakup action reduces the typical length of fragments, r (right arrow) alpha r, by an independent random multiplier alpha (0 Saveliev, the fragmentation under the scaling symmetry has been reviewed as a continuous evolution process with new features established. The objective of this paper is twofold. First, the paper synthesizes and completes theoretical part of Gorokhovski & Saveliev. Second, the paper shows a new application of the fragmentation theory under the scale invariance. This application concerns the turbulent cascade with intermittency. We formulate here a model describing the evolution of the velocity increment distribution along the progressively decreasing length scale. The model shows that when the turbulent length scale gets smaller, the velocity increment distribution has central growing peak and develops stretched tails. The intermittency in turbulence is manifested in the same way: large fluctuations of velocity provoke highest strain in narrow (dissipative) regions of flow.

Coexistence of intermittencies in the neuronal network of the epileptic brain.

Science.gov (United States)

Koronovskii, Alexey A; Hramov, Alexander E; Grubov, Vadim V; Moskalenko, Olga I; Sitnikova, Evgenia; Pavlov, Alexey N

2016-03-01

Intermittent behavior occurs widely in nature. At present, several types of intermittencies are known and well-studied. However, consideration of intermittency has usually been limited to the analysis of cases when only one certain type of intermittency takes place. In this paper, we report on the temporal behavior of the complex neuronal network in the epileptic brain, when two types of intermittent behavior coexist and alternate with each other. We prove the presence of this phenomenon in physiological experiments with WAG/Rij rats being the model living system of absence epilepsy. In our paper, the deduced theoretical law for distributions of the lengths of laminar phases prescribing the power law with a degree of -2 agrees well with the experimental neurophysiological data.

Feasibility of thermophilic anaerobic processes for treating waste activated sludge under low HRT and intermittent mixing.

Science.gov (United States)

Leite, Wanderli; Magnus, Bruna Scandolara; Guimarães, Lorena Bittencourt; Gottardo, Marco; Belli Filho, Paulo

2017-10-01

Thermophilic anaerobic digestion (AD) arises as an optimized solution for the waste activated sludge (WAS) management. However, there are few feasibility studies using low solids content typically found in the WAS, and that consider uncommon operational conditions such as intermittent mixing and low hydraulic retention time (HRT). In this investigation, a single-stage pilot reactor was used to treat WAS at low HRT (13, 9, 6 and 5 days) and intermittent mixing (withholding mixing 2 h prior feeding). Thermophilic anaerobic digestion (55 °C) was initiated from a mesophilic digester (35 °C) by the one-step startup strategy. Although instabilities on partial alkalinity (1245-3000 mgCaCO 3 /L), volatile fatty acids (1774-6421 mg/L acetic acid) and biogas production (0.21-0.09 m 3 /m 3 reactor .d) were observed, methanogenesis started to recover in 18 days. The thermophilic treatment of WAS at 13 and 9 days HRT efficiently converted VS into biogas (22 and 21%, respectively) and achieved high biogas yield (0.24 and 0.22 m 3 /kgVS fed , respectively). Intermittent mixing improved the retention of methanogens inside the reactor and reduced the washout effect even at low HRT (5% TS). Copyright © 2017 Elsevier Ltd. All rights reserved.

An Improved Ensemble of Random Vector Functional Link Networks Based on Particle Swarm Optimization with Double Optimization Strategy.

Science.gov (United States)

Ling, Qing-Hua; Song, Yu-Qing; Han, Fei; Yang, Dan; Huang, De-Shuang

2016-01-01

For ensemble learning, how to select and combine the candidate classifiers are two key issues which influence the performance of the ensemble system dramatically. Random vector functional link networks (RVFL) without direct input-to-output links is one of suitable base-classifiers for ensemble systems because of its fast learning speed, simple structure and good generalization performance. In this paper, to obtain a more compact ensemble system with improved convergence performance, an improved ensemble of RVFL based on attractive and repulsive particle swarm optimization (ARPSO) with double optimization strategy is proposed. In the proposed method, ARPSO is applied to select and combine the candidate RVFL. As for using ARPSO to select the optimal base RVFL, ARPSO considers both the convergence accuracy on the validation data and the diversity of the candidate ensemble system to build the RVFL ensembles. In the process of combining RVFL, the ensemble weights corresponding to the base RVFL are initialized by the minimum norm least-square method and then further optimized by ARPSO. Finally, a few redundant RVFL is pruned, and thus the more compact ensemble of RVFL is obtained. Moreover, in this paper, theoretical analysis and justification on how to prune the base classifiers on classification problem is presented, and a simple and practically feasible strategy for pruning redundant base classifiers on both classification and regression problems is proposed. Since the double optimization is performed on the basis of the single optimization, the ensemble of RVFL built by the proposed method outperforms that built by some single optimization methods. Experiment results on function approximation and classification problems verify that the proposed method could improve its convergence accuracy as well as reduce the complexity of the ensemble system.

Sliding Intermittent Control for BAM Neural Networks with Delays

Directory of Open Access Journals (Sweden)

Jianqiang Hu

2013-01-01

Full Text Available This paper addresses the exponential stability problem for a class of delayed bidirectional associative memory (BAM neural networks with delays. A sliding intermittent controller which takes the advantages of the periodically intermittent control idea and the impulsive control scheme is proposed and employed to the delayed BAM system. With the adjustable parameter taking different particular values, such a sliding intermittent control method can comprise several kinds of control schemes as special cases, such as the continuous feedback control, the impulsive control, the periodically intermittent control, and the semi-impulsive control. By using analysis techniques and the Lyapunov function methods, some sufficient criteria are derived for the closed-loop delayed BAM neural networks to be globally exponentially stable. Finally, two illustrative examples are given to show the effectiveness of the proposed control scheme and the obtained theoretical results.

Intermittent intravenous followed by intermittent oral 1 alpha(OH)D3 treatment of secondary hyperparathyroidism in uraemia

DEFF Research Database (Denmark)

Brandi, L; Daugaard, H; Egsmose, C

1996-01-01

OBJECTIVES: To examine whether intermittent oral 1 alpha(OH)D3 treatment of patients on haemodialysis with secondary hyperparathyroidism (HPT) was able to maintain the marked suppression of PTH, which previously had been induced by an intermittent intravenous administration of 1 alpha(OH)D3....... Simultaneously, the effect of the different routes of administration of 1 alpha(OH)D3 on the circulating levels of N- and C-terminal PTH fragments was measured. DESIGN: An open study of patients on chronic haemodialysis. SETTING: Renal division, Rigshospitalet, Copenhagen, Denmark. SUBJECTS: A total of 26...

A nuclear reload optimization approach using a real coded genetic algorithm with random keys

International Nuclear Information System (INIS)

Lima, Alan M.M. de; Schirru, Roberto; Medeiros, Jose A.C.C.

2009-01-01

The fuel reload of a Pressurized Water Reactor is made whenever the burn up of the fuel assemblies in the nucleus of the reactor reaches a certain value such that it is not more possible to maintain a critical reactor producing energy at nominal power. The problem of fuel reload optimization consists on determining the positioning of the fuel assemblies within the nucleus of the reactor in an optimized way to minimize the cost benefit relationship of fuel assemblies cost per maximum burn up, and also satisfying symmetry and safety restrictions. The fuel reload optimization problem difficulty grows exponentially with the number of fuel assemblies in the nucleus of the reactor. During decades the fuel reload optimization problem was solved manually by experts that used their knowledge and experience to build configurations of the reactor nucleus, and testing them to verify if safety restrictions of the plant are satisfied. To reduce this burden, several optimization techniques have been used, included the binary code genetic algorithm. In this work we show the use of a real valued coded approach of the genetic algorithm, with different recombination methods, together with a transformation mechanism called random keys, to transform the real values of the genes of each chromosome in a combination of discrete fuel assemblies for evaluation of the reload optimization. Four different recombination methods were tested: discrete recombination, intermediate recombination, linear recombination and extended linear recombination. For each of the 4 recombination methods 10 different tests using different seeds for the random number generator were conducted 10 generating, totaling 40 tests. The results of the application of the genetic algorithm are shown with formulation of real numbers for the problem of the nuclear reload of the plant Angra 1 type PWR. Since the best results in the literature for this problem were found by the parallel PSO we will it use for comparison

Subsurface Controls on Stream Intermittency in a Semi-Arid Landscape

Science.gov (United States)

Dohman, J.; Godsey, S.; Thackray, G. D.; Hale, R. L.; Wright, K.; Martinez, D.

2017-12-01

Intermittent streams currently constitute 30% to greater than 50% of the global river network. In addition, the number of intermittent streams is expected to increase due to changes in land use and climate. These streams provide important ecosystem services, such as water for irrigation, increased biodiversity, and high rates of nutrient cycling. Many hydrological studies have focused on mapping current intermittent flow regimes or evaluating long-term flow records, but very few have investigated the underlying causes of stream intermittency. The disconnection and reconnection of surface flow reflects the capacity of the subsurface to accommodate flow, so characterizing subsurface flow is key to understanding stream drying. We assess how subsurface flow paths control local surface flows during low-flow periods, including intermittency. Water table dynamics were monitored in an intermittent reach of Gibson Jack Creek in southeastern Idaho. Four transects were delineated with a groundwater well located in the hillslope, riparian zone, and in the stream, for a total of 12 groundwater wells. The presence or absence of surface flow was determined by frequent visual observations as well as in situ loggers every 30m along the 200m study reach. The rate of surface water drying was measured in conjunction with temperature, precipitation, subsurface hydraulic conductivity, hillslope-riparian-stream connectivity and subsurface travel time. Initial results during an unusually wet year suggest different responses in reaches that were previously observed to occasionally cease flowing. Flows in the intermittent reaches had less coherent and lower amplitude diel variations during base flow periods than reaches that had never been observed to dry out. Our findings will help contribute to our understanding of mechanisms driving expansion and contraction cycles in intermittent streams, increase our ability to predict how land use and climate change will affect flow regimes, and

Photoluminescence intermittency of semiconductor quantum dots in dielectric environments

Energy Technology Data Exchange (ETDEWEB)

Isaac, A.

2006-08-11

The experimental studies presented in this thesis deal with the photoluminescence intermittency of semiconductor quantum dots in different dielectric environments. Detailed analysis of intermittency statistics from single capped CdSe/ZnS, uncapped CdSe and water dispersed CdSe/ZnS QDs in different matrices provide experimental evidence for the model of photoionization with a charge ejected into the surrounding matrix as the source of PL intermittency phenomenon. We propose a self-trapping model to explain the increase of dark state lifetimes with the dielectric constant of the matrix. (orig.)

Intermittent hyperthyreosis

International Nuclear Information System (INIS)

Sulman, F.G.; Tal, E.; Pfeifer, Y.; Superstine, E.

1975-01-01

Intermittent hyperthyreosis occurs under various forms of stress, especially heat stress. The clinician may diagnose such cases as masked or apathetic hyperthyroidism or 'forme fruste' hyperthyreosis or thyroid autonomy. As most routine and standard tests may here yield inconsistent results, it is the patients' anamnesis which may provide the clue. Our Bioclimatology Unit has now seen over 100 cases in which thyroid hypersensitivity towards heat was the most prominent syndrome: 10-15% of weather-sensitive patients are affected. The patients complain before or during heat spells of such contradictory symptoms as insomnia, irritability, tension, tachycardia, palpitations, precordial pain, dyspnoe, flushes with sweating or chills, tremor, abdominal pain or diarrhea, polyuria or pollakisuria, weight loss in spite of ravenous appetite, fatigue, exhaustion, depression, adynamia, lack of concentration and confusion. Determination of urinary neurohormones allows a differential diagnosis, intermittent hyperthyreosis being characterized by three cardinal symptoms: tachycardia - every case with more than 80 pulse beats being suspect (not specific); urinary histamine - every case excreting more than 90 μg/day being suspect. Again the drawback of this test is its lack of specificity, as histamine may also be increased in cases of allergy and spondylitis; urinary thyroxine - every case excreting more than 20 μg/day T-4 being suspect. This is the only specific test. Therapy should make use of lithium carbonate and betablockers. Propyl thiouracil is rarely required. (orig.) [de

Comparison of Intermittent and Bolus Enteral Feeding Methods on Enteral Feeding Intolerance of Patients with Sepsis: A Triple-blind Controlled Trial in Intensive Care Units.

Science.gov (United States)

Nasiri, Morteza; Farsi, Zahra; Ahangari, Mojtaba; Dadgari, Fahimeh

2017-10-01

BACKGROUND Recent trials have shown controversial results on which enteral feeding methods has a lower risk of enteral feeding intolerance. Therefore, we aimed to compare two methods of bolus and intermittent feeding on enteral feeding intolerance of patients with sepsis. METHODS This triple-blind randomized controlled trial was conducted on 60 patients with sepsis, who were fed through tubes for at least 3 days. The patients were randomly assigned into bolus feeding, intermittent feeding, and control groups. Enteral feeding intolerance of all patients was recorded in 3 consecutive days by a researcher-made checklist including the data on gastric residual volume, vomiting, diarrhea, constipation, and abdominal distension. RESULTS There were no significant differences between the three studied groups in none of the intervention days pertaining to constipation, diarrhea, vomiting, abdominal distention, and gastric residual volume ( p > 0.05). Also, no statistically significant difference was found between all variables in the three studied groups during the 3 days ( p > 0.05). CONCLUSION As enteral feeding intolerance of patients with sepsis was similar in both bolus and intermittent feeding methods, it can be concluded that bolus method can still be used as a standard method to decrease the risk of enteral feeding intolerance if it is used properly.

Prevention of urethral stricture recurrence using clean intermittent self-catheterization

DEFF Research Database (Denmark)

Kjaergaard, B; Walter, S; Bartholin, J

1994-01-01

OBJECTIVE: To investigate the effect of clean intermittent catheterization (CIC) on prevention of urethral stricture recurrence after internal urethrotomy. PATIENTS AND METHODS: Of 55 men who were randomly selected, 43 completed the investigation. Of these, 21 patients performed CIC weekly for 1...... year following Sachse's operation for urethral stricture and 22 patients formed the control group after the same operation. All had an objective examination for urethral stricture every 2 months after surgery. RESULTS: Significantly fewer (P urethral stricture...... within the first postoperative year in the CIC group (n = 4) compared with the control group (n = 15). No CIC complications were seen, and patients who completed the CIC programme considered the method fully acceptable. CONCLUSION: Weekly CIC is a simple method of reducing the frequency of urethral...

The dialysis catheter and infectious peritonitis in intermittent peritoneal dialysis

DEFF Research Database (Denmark)

Kolmos, Hans Jørn; Hemmeløff Andersen, Karl Erik; Hansen, Lise

1984-01-01

118 episodes of infectious peritonitis registered among 156 patients treated with intermittent peritoneal dialysis over a 5-yr period were analysed with special reference to potential routes of infection associated with the dialysis catheter. Peritonitis was randomly distributed among the patients......, and the change of keeping free of peritonitis declined exponentially with time. The main factor determining the individual number of episodes was the total space of time, in which a patient had been wearing a dialysis catheter, whereas the number of catheter disconnections played no significant role. A relative...... preponderance of cases due to Enterobacteriaceae was noted within the first week after catheter implantation. In contrast with this, peritonitis with skin microorganisms was not associated with the implantation of catheters....

Volatile decision dynamics: experiments, stochastic description, intermittency control and traffic optimization

Science.gov (United States)

Helbing, Dirk; Schönhof, Martin; Kern, Daniel

2002-06-01

The coordinated and efficient distribution of limited resources by individual decisions is a fundamental, unsolved problem. When individuals compete for road capacities, time, space, money, goods, etc, they normally make decisions based on aggregate rather than complete information, such as TV news or stock market indices. In related experiments, we have observed a volatile decision dynamics and far-from-optimal payoff distributions. We have also identified methods of information presentation that can considerably improve the overall performance of the system. In order to determine optimal strategies of decision guidance by means of user-specific recommendations, a stochastic behavioural description is developed. These strategies manage to increase the adaptibility to changing conditions and to reduce the deviation from the time-dependent user equilibrium, thereby enhancing the average and individual payoffs. Hence, our guidance strategies can increase the performance of all users by reducing overreaction and stabilizing the decision dynamics. These results are highly significant for predicting decision behaviour, for reaching optimal behavioural distributions by decision support systems and for information service providers. One of the promising fields of application is traffic optimization.

Evaluating the optimal timing of surgical antimicrobial prophylaxis: study protocol for a randomized controlled trial.

Science.gov (United States)

Mujagic, Edin; Zwimpfer, Tibor; Marti, Walter R; Zwahlen, Marcel; Hoffmann, Henry; Kindler, Christoph; Fux, Christoph; Misteli, Heidi; Iselin, Lukas; Lugli, Andrea Kopp; Nebiker, Christian A; von Holzen, Urs; Vinzens, Fabrizio; von Strauss, Marco; Reck, Stefan; Kraljević, Marko; Widmer, Andreas F; Oertli, Daniel; Rosenthal, Rachel; Weber, Walter P

2014-05-24

Surgical site infections are the most common hospital-acquired infections among surgical patients. The administration of surgical antimicrobial prophylaxis reduces the risk of surgical site infections . The optimal timing of this procedure is still a matter of debate. While most studies suggest that it should be given as close to the incision time as possible, others conclude that this may be too late for optimal prevention of surgical site infections. A large observational study suggests that surgical antimicrobial prophylaxis should be administered 74 to 30 minutes before surgery. The aim of this article is to report the design and protocol of a randomized controlled trial investigating the optimal timing of surgical antimicrobial prophylaxis. In this bi-center randomized controlled trial conducted at two tertiary referral centers in Switzerland, we plan to include 5,000 patients undergoing general, oncologic, vascular and orthopedic trauma procedures. Patients are randomized in a 1:1 ratio into two groups: one receiving surgical antimicrobial prophylaxis in the anesthesia room (75 to 30 minutes before incision) and the other receiving surgical antimicrobial prophylaxis in the operating room (less than 30 minutes before incision). We expect a significantly lower rate of surgical site infections with surgical antimicrobial prophylaxis administered more than 30 minutes before the scheduled incision. The primary outcome is the occurrence of surgical site infections during a 30-day follow-up period (one year with an implant in place). When assuming a 5% surgical site infection risk with administration of surgical antimicrobial prophylaxis in the operating room, the planned sample size has an 80% power to detect a relative risk reduction for surgical site infections of 33% when administering surgical antimicrobial prophylaxis in the anesthesia room (with a two-sided type I error of 5%). We expect the study to be completed within three years. The results of this

Intermittent fasting: A “new” historical strategy for controlling seizures?

OpenAIRE

Hartman, Adam L.; Rubenstein, James E.; Kossoff, Eric H.

2012-01-01

In antiquity, fasting was a treatment for epilepsy and a rationale for the ketogenic diet (KD). Preclinical data indicate the KD and intermittent fasting do not share identical anticonvulsant mechanisms. We implemented an intermittent fasting regimen in six children with an incomplete response to a KD. Three patients adhered to the combined intermittent fasting/KD regimen for 2 months and four had transient improvement in seizure control, albeit with some hunger-related adverse reactions.

Optimal image alignment with random projections of manifolds: algorithm and geometric analysis.

Science.gov (United States)

Kokiopoulou, Effrosyni; Kressner, Daniel; Frossard, Pascal

2011-06-01

This paper addresses the problem of image alignment based on random measurements. Image alignment consists of estimating the relative transformation between a query image and a reference image. We consider the specific problem where the query image is provided in compressed form in terms of linear measurements captured by a vision sensor. We cast the alignment problem as a manifold distance minimization problem in the linear subspace defined by the measurements. The transformation manifold that represents synthesis of shift, rotation, and isotropic scaling of the reference image can be given in closed form when the reference pattern is sparsely represented over a parametric dictionary. We show that the objective function can then be decomposed as the difference of two convex functions (DC) in the particular case where the dictionary is built on Gaussian functions. Thus, the optimization problem becomes a DC program, which in turn can be solved globally by a cutting plane method. The quality of the solution is typically affected by the number of random measurements and the condition number of the manifold that describes the transformations of the reference image. We show that the curvature, which is closely related to the condition number, remains bounded in our image alignment problem, which means that the relative transformation between two images can be determined optimally in a reduced subspace.

Impact of Targeted Preoperative Optimization on Clinical Outcome in Emergency Abdominal Surgeries: A Prospective Randomized Trial.

Science.gov (United States)

Sethi, Ashish; Debbarma, Miltan; Narang, Neeraj; Saxena, Anudeep; Mahobia, Mamta; Tomar, Gaurav Singh

2018-01-01

Perforation peritonitis continues to be one of the most common surgical emergencies that need a surgical intervention most of the times. Anesthesiologists are invariably involved in managing such cases efficiently in perioperative period. The assessment and evaluation of Acute Physiology and Chronic Health Evaluation II (APACHE II) score at presentation and 24 h after goal-directed optimization, administration of empirical broad-spectrum antibiotics, and definitive source control postoperatively. Outcome assessment in terms of duration of hospital stay and mortality in with or without optimization was also measured. It is a prospective, randomized, double-blind controlled study in hospital setting. One hundred and one patients aged ≥18 years, of the American Society of Anesthesiologists physical Status I and II (E) with clinical diagnosis of perforation peritonitis posted for surgery were enrolled. Enrolled patients were randomly divided into two groups. Group A is optimized by goal-directed optimization protocol in the preoperative holding room by anesthesiology residents whereas in Group S, managed by surgery residents in the surgical wards without any fixed algorithm. The assessment of APACHE II score was done as a first step on admission and 24 h postoperatively. Duration of hospital stay and mortality in both the groups were also measured and compared. Categorical data are presented as frequency counts (percent) and compared using the Chi-square or Fisher's exact test. The statistical significance for categorical variables was determined by Chi-square analysis. For continuous variables, a two-sample t -test was applied. The mean APACHE II score on admission in case and control groups was comparable. Significant lowering of serial scores in case group was observed as compared to control group ( P = 0.02). There was a significant lowering of mean duration of hospital stay seen in case group (9.8 ± 1.7 days) as compared to control group ( P = 0

Sinusoidal visuomotor tracking: intermittent servo-control or coupled oscillations?

Science.gov (United States)

Russell, D M; Sternad, D

2001-12-01

In visuomotor tasks that involve accuracy demands, small directional changes in the trajectories have been taken as evidence of feedback-based error corrections. In the present study variability, or intermittency, in visuomanual tracking of sinusoidal targets was investigated. Two lines of analyses were pursued: First, the hypothesis that humans fundamentally act as intermittent servo-controllers was re-examined, probing the question of whether discontinuities in the movement trajectory directly imply intermittent control. Second, an alternative hypothesis was evaluated: that rhythmic tracking movements are generated by entrainment between the oscillations of the target and the actor, such that intermittency expresses the degree of stability. In 2 experiments, participants (N = 6 in each experiment) swung 1 of 2 different hand-held pendulums, tracking a rhythmic target that oscillated at different frequencies with a constant amplitude. In 1 line of analyses, the authors tested the intermittency hypothesis by using the typical kinematic error measures and spectral analysis. In a 2nd line, they examined relative phase and its variability, following analyses of rhythmic interlimb coordination. The results showed that visually guided corrective processes play a role, especially for slow movements. Intermittency, assessed as frequency and power components of the movement trajectory, was found to change as a function of both target frequency and the manipulandum's inertia. Support for entrainment was found in conditions in which task frequency was identical to or higher than the effector's eigenfrequency. The results suggest that it is the symmetry between task and effector that determines which behavioral regime is dominant.

Comparison of Clenshaw–Curtis and Leja Quasi-Optimal Sparse Grids for the Approximation of Random PDEs

KAUST Repository

Nobile, Fabio; Tamellini, Lorenzo; Tempone, Raul

2015-01-01

In this work we compare different families of nested quadrature points, i.e. the classic Clenshaw–Curtis and various kinds of Leja points, in the context of the quasi-optimal sparse grid approximation of random elliptic PDEs. Numerical evidence

Intermittent, noncyclic dysfunction of a mechanical aortic prosthesis by pannus formation.

Science.gov (United States)

Giroux, Sylvie K; Labinaz, Marino X; Grisoli, Dominique; Klug, Andrew P; Veinot, John P; Burwash, Ian G

2010-01-01

Mechanical aortic prosthesis dysfunction can result from thrombosis or pannus formation. Pannus formation usually restricts systolic excursion of the occluding disk, resulting in progressive stenosis of the aortic prosthesis. Intermittent dysfunction of a mechanical aortic prosthesis is usually ascribed to thrombus formation. We describe an unusual case of intermittent, noncyclic dysfunction of a mechanical aortic prosthesis due to pannus formation in the absence of systolic restriction of disk excursion that presented with intermittent massive aortic regurgitation, severe ischemia, and shock. Pannus formation should be considered as a potential cause of acute intermittent severe aortic regurgitation in a patient with a mechanical aortic prosthesis.

Intermittent fasting: A “new” historical strategy for controlling seizures?

Science.gov (United States)

Hartman, Adam L.; Rubenstein, James E.; Kossoff, Eric H.

2013-01-01

Summary In antiquity, fasting was a treatment for epilepsy and a rationale for the ketogenic diet (KD). Preclinical data indicate the KD and intermittent fasting do not share identical anticonvulsant mechanisms. We implemented an intermittent fasting regimen in six children with an incomplete response to a KD. Three patients adhered to the combined intermittent fasting/KD regimen for 2 months and four had transient improvement in seizure control, albeit with some hunger-related adverse reactions. PMID:23206889

Quantifying spatial and temporal patterns of flow intermittency using spatially contiguous runoff data

Science.gov (United States)

Yu (于松延), Songyan; Bond, Nick R.; Bunn, Stuart E.; Xu, Zongxue; Kennard, Mark J.

2018-04-01

River channel drying caused by intermittent stream flow is a widely-recognized factor shaping stream ecosystems. There is a strong need to quantify the distribution of intermittent streams across catchments to inform management. However, observational gauge networks provide only point estimates of streamflow variation. Increasingly, this limitation is being overcome through the use of spatially contiguous estimates of the terrestrial water-balance, which can also assist in estimating runoff and streamflow at large-spatial scales. Here we proposed an approach to quantifying spatial and temporal variation in monthly flow intermittency throughout river networks in eastern Australia. We aggregated gridded (5 × 5 km) monthly water-balance data with a hierarchically nested catchment dataset to simulate catchment runoff accumulation throughout river networks from 1900 to 2016. We also predicted zero flow duration for the entire river network by developing a robust predictive model relating measured zero flow duration (% months) to environmental predictor variables (based on 43 stream gauges). We then combined these datasets by using the predicted zero flow duration from the regression model to determine appropriate 'zero' flow thresholds for the modelled discharge data, which varied spatially across the catchments examined. Finally, based on modelled discharge data and identified actual zero flow thresholds, we derived summary metrics describing flow intermittency across the catchment (mean flow duration and coefficient-of-variation in flow permanence from 1900 to 2016). We also classified the relative degree of flow intermittency annually to characterise temporal variation in flow intermittency. Results showed that the degree of flow intermittency varied substantially across streams in eastern Australia, ranging from perennial streams flowing permanently (11-12 months) to strongly intermittent streams flowing 4 months or less of year. Results also showed that the

Uncoupling of Vascular Nitric Oxide Synthase Caused by Intermittent Hypoxia

Directory of Open Access Journals (Sweden)

Mohammad Badran

2016-01-01

Full Text Available Objective. Obstructive sleep apnea (OSA, characterized by chronic intermittent hypoxia (CIH, is often present in diabetic (DB patients. Both conditions are associated with endothelial dysfunction and cardiovascular disease. We hypothesized that diabetic endothelial dysfunction is further compromised by CIH. Methods. Adult male diabetic (BKS.Cg-Dock7m +/+ Leprdb/J (db/db mice (10 weeks old and their heterozygote littermates were subjected to CIH or intermittent air (IA for 8 weeks. Mice were separated into 4 groups: IA (intermittent air nondiabetic, IH (intermittent hypoxia nondiabetic, IADB (intermittent air diabetic, and IHDB (intermittent hypoxia diabetic groups. Endothelium-dependent and endothelium-independent relaxation and modulation by basal nitric oxide (NO were analyzed using wire myograph. Plasma 8-isoprostane, interleukin-6 (IL-6, and asymmetric dimethylarginine (ADMA were measured using ELISA. Uncoupling of eNOS was measured using dihydroethidium (DHE staining. Results. Endothelium-dependent vasodilation and basal NO production were significantly impaired in the IH and IADB group compared to IA group but was more pronounced in IHDB group. Levels of 8-isoprostane, IL-6, ADMA, and eNOS uncoupling were ≈2-fold higher in IH and IADB groups and were further increased in the IHDB group. Conclusion. Endothelial dysfunction is more pronounced in diabetic mice subjected to CIH compared to diabetic or CIH mice alone. Oxidative stress, ADMA, and eNOS uncoupling were exacerbated by CIH in diabetic mice.

Accelerated anaerobic hydrolysis rates under a combination of intermittent aeration and anaerobic conditions

DEFF Research Database (Denmark)

Jensen, T. R.; Lastra Milone, T.; Petersen, G.

2017-01-01

Anaerobic hydrolysis in activated return sludge was investigated in laboratory scale experiments to find if intermittent aeration would accelerate anaerobic hydrolysis rates compared to anaerobic hydrolysis rates under strict anaerobic conditions. The intermittent reactors were set up in a 240 h...... for calculating hydrolysis rates based on soluble COD were compared. Two-way ANOVA with the Bonferroni post-test was performed in order to register any significant difference between reactors with intermittent aeration and strictly anaerobic conditions respectively. The experiment demonstrated a statistically...... significant difference in favor of the reactors with intermittent aeration showing a tendency towards accelerated anaerobic hydrolysis rates due to application of intermittent aeration. The conclusion of the work is thus that intermittent aeration applied in the activated return sludge process (ARP) can...

Intermittent pneumatic compression of legs increases microcirculation in distant skeletal muscle.

Science.gov (United States)

Liu, K; Chen, L E; Seaber, A V; Johnson, G W; Urbaniak, J R

1999-01-01

Intermittent pneumatic compression has been established as a method of clinically preventing deep vein thrombosis, but the mechanism has not been documented. This study observed the effects of intermittent pneumatic compression of legs on the microcirculation of distant skeletal muscle. The cremaster muscles of 80 male rats were exposed, a specially designed intermittent pneumatic-compression device was applied to both legs for 60 minutes, and the microcirculation of the muscles was assessed by measurement of the vessel diameter in three categories (10-20, 21-40, and 41-70 microm) for 120 minutes. The results showed significant vasodilation in arterial and venous vessels during the application of intermittent pneumatic compression, which disappeared after termination of the compression. The vasodilation reached a maximum 30 minutes after initiation of the compression and could be completely blocked by an inhibitor of nitric oxide synthase, NG-monomethyl-L-arginine (10 micromol/min). A 120-minute infusion of NG-monomethyl-L-arginine, beginning coincident with 60 minutes of intermittent pneumatic compression, resulted in a significant decrease in arterial diameter that remained at almost the same level after termination of the compression. The magnitude of the decrease in diameter in the group treated with intermittent pneumatic compression and NG-monomethyl-L-arginine was comparable with that in the group treated with NG-monomethyl-L-arginine alone. The results imply that the production of nitric oxide is involved in the positive influence of intermittent pneumatic compression on circulation. It is postulated that the rapid increase in venous velocity induced by intermittent pneumatic compression produces strong shear stress on the vascular endothelium, which stimulates an increased release of nitric oxide and thereby causes systemic vasodilation.

Intermittent synchronization in a network of bursting neurons

Science.gov (United States)

Park, Choongseok; Rubchinsky, Leonid L.

2011-09-01

Synchronized oscillations in networks of inhibitory and excitatory coupled bursting neurons are common in a variety of neural systems from central pattern generators to human brain circuits. One example of the latter is the subcortical network of the basal ganglia, formed by excitatory and inhibitory bursters of the subthalamic nucleus and globus pallidus, involved in motor control and affected in Parkinson's disease. Recent experiments have demonstrated the intermittent nature of the phase-locking of neural activity in this network. Here, we explore one potential mechanism to explain the intermittent phase-locking in a network. We simplify the network to obtain a model of two inhibitory coupled elements and explore its dynamics. We used geometric analysis and singular perturbation methods for dynamical systems to reduce the full model to a simpler set of equations. Mathematical analysis was completed using three slow variables with two different time scales. Intermittently, synchronous oscillations are generated by overlapped spiking which crucially depends on the geometry of the slow phase plane and the interplay between slow variables as well as the strength of synapses. Two slow variables are responsible for the generation of activity patterns with overlapped spiking, and the other slower variable enhances the robustness of an irregular and intermittent activity pattern. While the analyzed network and the explored mechanism of intermittent synchrony appear to be quite generic, the results of this analysis can be used to trace particular values of biophysical parameters (synaptic strength and parameters of calcium dynamics), which are known to be impacted in Parkinson's disease.

Abdominal blood pool scintigraphy in the management of acute or intermittent gastrointestinal bleeding

International Nuclear Information System (INIS)

Kalff, V.; Kelly, M.J.; Dudley, F.; Metz, G.

1983-01-01

Gastrointestinal blood pool scintigraphy, using a modified in-vivo blood cell labelling technique with technetium-99, is a new, easily performed, non-invasive procedure. It is valuable in screening patients with acute or intermittent gastrointestinal blood loss in whom duodenoscopic and sigmoidoscopic findings are unhelpful. This paper reviews the value of this scintigraphic technique over the first eight months of its use in a major teaching hospital, and compares the results with other published data. If used and interpreted appropriately, scintigraphy is sensitive in detecting and localizing the bleeding site, and is very helpful in indicating the optimal timing of emergency contrast angiography

Random Sequence for Optimal Low-Power Laser Generated Ultrasound

Science.gov (United States)

Vangi, D.; Virga, A.; Gulino, M. S.

2017-08-01

Low-power laser generated ultrasounds are lately gaining importance in the research world, thanks to the possibility of investigating a mechanical component structural integrity through a non-contact and Non-Destructive Testing (NDT) procedure. The ultrasounds are, however, very low in amplitude, making it necessary to use pre-processing and post-processing operations on the signals to detect them. The cross-correlation technique is used in this work, meaning that a random signal must be used as laser input. For this purpose, a highly random and simple-to-create code called T sequence, capable of enhancing the ultrasound detectability, is introduced (not previously available at the state of the art). Several important parameters which characterize the T sequence can influence the process: the number of pulses Npulses , the pulse duration δ and the distance between pulses dpulses . A Finite Element FE model of a 3 mm steel disk has been initially developed to analytically study the longitudinal ultrasound generation mechanism and the obtainable outputs. Later, experimental tests have shown that the T sequence is highly flexible for ultrasound detection purposes, making it optimal to use high Npulses and δ but low dpulses . In the end, apart from describing all phenomena that arise in the low-power laser generation process, the results of this study are also important for setting up an effective NDT procedure using this technology.

Intermittent pneumatic compression to prevent venous thromboembolism in patients with high risk of bleeding hospitalized in intensive care units: the CIREA1 randomized trial.

Science.gov (United States)

Vignon, Philippe; Dequin, Pierre-François; Renault, Anne; Mathonnet, Armelle; Paleiron, Nicolas; Imbert, Audrey; Chatellier, Delphine; Gissot, Valérie; Lhéritier, Gwenaelle; Aboyans, Victor; Prat, Gwenael; Garot, Denis; Boulain, Thierry; Diehl, Jean-Luc; Bressollette, Luc; Delluc, Aurélien; Lacut, Karine

2013-05-01

Venous thromboembolism (VTE) is a frequent and serious problem in intensive care units (ICU). Anticoagulant treatments have demonstrated their efficacy in preventing VTE. However, when the bleeding risk is high, they are contraindicated, and mechanical devices are recommended. To date, mechanical prophylaxis has not been rigorously evaluated in any trials in ICU patients. In this multicenter, open-label, randomized trial with blinded evaluation of endpoints, we randomly assigned 407 patients with a high risk of bleeding to receive intermittent pneumatic compression (IPC) associated with graduated compression stockings (GCS) or GCS alone for 6 days during their ICU stay. The primary endpoint was the occurrence of a VTE between days 1 and 6, including nonfatal symptomatic documented VTE, or death due to a pulmonary embolism, or asymptomatic deep vein thrombosis detected by ultrasonography systematically performed on day 6. The primary outcome was assessed in 363 patients (89.2%). By day 6, the incidence of the primary outcome was 5.6% (10 of 179 patients) in the IPC + GCS group and 9.2% (17 of 184 patients) in the GCS group (relative risk 0.60; 95% confidence interval 0.28-1.28; p = 0.19). Tolerance of IPC was poor in only 12 patients (6.0%). No intergroup difference in mortality rate was observed. With the limitation of a low statistical power, our results do not support the superiority of the combination of IPC + GCS compared to GCS alone to prevent VTE in ICU patients at high risk of bleeding.

Comparing microbial water quality in an intermittent and continuous piped water supply.

Science.gov (United States)

Kumpel, Emily; Nelson, Kara L

2013-09-15

Supplying piped water intermittently is a common practice throughout the world that increases the risk of microbial contamination through multiple mechanisms. Converting an intermittent supply to a continuous supply has the potential to improve the quality of water delivered to consumers. To understand the effects of this upgrade on water quality, we tested samples from reservoirs, consumer taps, and drinking water provided by households (e.g. from storage containers) from an intermittent and continuous supply in Hubli-Dharwad, India, over one year. Water samples were tested for total coliform, Escherichia coli, turbidity, free chlorine, and combined chlorine. While water quality was similar at service reservoirs supplying the continuous and intermittent sections of the network, indicator bacteria were detected more frequently and at higher concentrations in samples from taps supplied intermittently compared to those supplied continuously (p supply, with 0.7% of tap samples positive compared to 31.7% of intermittent water supply tap samples positive for E. coli. In samples from both continuously and intermittently supplied taps, higher concentrations of total coliform were measured after rainfall events. While source water quality declined slightly during the rainy season, only tap water from intermittent supply had significantly more indicator bacteria throughout the rainy season compared to the dry season. Drinking water samples provided by households in both continuous and intermittent supplies had higher concentrations of indicator bacteria than samples collected directly from taps. Most households with continuous supply continued to store water for drinking, resulting in re-contamination, which may reduce the benefits to water quality of converting to continuous supply. Copyright © 2013 Elsevier Ltd. All rights reserved.

Generation of intermittent gravitocapillary waves via parametric forcing

Science.gov (United States)

Castillo, Gustavo; Falcón, Claudio

2018-04-01

We report on the generation of an intermittent wave field driven by a horizontally moving wave maker interacting with Faraday waves. The spectrum of the local gravitocapillary surface wave fluctuations displays a power law in frequency for a wide range of forcing parameters. We compute the probability density function of the local surface height increments, which show that they change strongly across time scales. The structure functions of these increments are shown to display power laws as a function of the time lag, with exponents that are nonlinear functions of the order of the structure function. We argue that the origin of this scale-invariant intermittent spectrum is the Faraday wave pattern breakup due to its advection by the propagating gravity waves. Finally, some interpretations are proposed to explain the appearance of this intermittent spectrum.

Intermittency in e+e- and lepton-hadron collisions

International Nuclear Information System (INIS)

Sugano, K.

1990-01-01

The intermittency data in e + e - and lepton-hadron collisions are reviewed. The power-law behavior of the moments has been established by various e + e - experiments and a μp experiment. The intermittency in the two-dimensional space of rapidity and azimuthal angle is much stronger than in the rapidity space only. The neutrino-nucleus data indicate significant effects from nuclear reinteractions. The LUND parton shower model fits the data better than the matrix element model without special retuning. The relations among the moments of different orders are in good agreement with the predictions by the negative binomial and pure birth distributions. The origin of the intermittency in e + e - and μp collisions is consistent with the self-similar cascade mechanism of jet formation. 11 refs., 7 figs

Prevention of deep vein thrombosis in potential neurosurgical patients. A randomized trial comparing graduated compression stockings alone or graduated compression stockings plus intermittent pneumatic compression with control

International Nuclear Information System (INIS)

Turpie, A.G.; Hirsh, J.; Gent, M.; Julian, D.; Johnson, J.

1989-01-01

In a randomized trial of neurosurgical patients, groups wearing graduated compression stockings alone (group 1) or graduated compression stockings plus intermittent pneumatic compression (IPC) (group 2) were compared with an untreated control group in the prevention of deep vein thrombosis (DVT). In both active treatment groups, the graduated compression stockings were continued for 14 days or until hospital discharge, if earlier. In group 2, IPC was continued for seven days. All patients underwent DVT surveillance with iodine 125-labeled fibrinogen leg scanning and impedance plethysmography. Venography was carried out if either test became abnormal. Deep vein thrombosis occurred in seven (8.8%) of 80 patients in group 1, in seven (9.0%) of 78 patients in group 2, and in 16 (19.8%) of 81 patients in the control group. The observed differences among these rates are statistically significant. The results of this study indicate that graduated compression stockings alone or in combination with IPC are effective methods of preventing DVT in neurosurgical patients

Chronic Intermittent Hypoxia Induces Atherosclerosis

OpenAIRE

Savransky, Vladimir; Nanayakkara, Ashika; Li, Jianguo; Bevans, Shannon; Smith, Philip L.; Rodriguez, Annabelle; Polotsky, Vsevolod Y.

2007-01-01

Rationale: Obstructive sleep apnea, a condition leading to chronic intermittent hypoxia (CIH), is associated with hyperlipidemia, atherosclerosis, and a high cardiovascular risk. A causal link between obstructive sleep apnea and atherosclerosis has not been established.

CFD simulation of fluid dynamic and biokinetic processes within activated sludge reactors under intermittent aeration regime.

Science.gov (United States)

Sánchez, F; Rey, H; Viedma, A; Nicolás-Pérez, F; Kaiser, A S; Martínez, M

2018-08-01

Due to the aeration system, biological reactors are the most energy-consuming facilities of convectional WWTPs. Many biological reactors work under intermittent aeration regime; the optimization of the aeration process (air diffuser layout, air flow rate per diffuser, aeration length …) is necessary to ensure an efficient performance; satisfying the effluent requirements with the minimum energy consumption. This work develops a CFD modelling of an activated sludge reactor (ASR) which works under intermittent aeration regime. The model considers the fluid dynamic and biological processes within the ASR. The biological simulation, which is transient, takes into account the intermittent aeration regime. The CFD modelling is employed for the selection of the aeration system of an ASR. Two different aeration configurations are simulated. The model evaluates the aeration power consumption necessary to satisfy the effluent requirements. An improvement of 2.8% in terms of energy consumption is achieved by modifying the air diffuser layout. An analysis of the influence of the air flow rate per diffuser on the ASR performance is carried out. The results show a reduction of 14.5% in the energy consumption of the aeration system when the air flow rate per diffuser is reduced. The model provides an insight into the aeration inefficiencies produced within ASRs. Copyright © 2018 Elsevier Ltd. All rights reserved.

Random mutagenesis of aspergillus niger and process optimization for enhanced production of glucose oxidase

International Nuclear Information System (INIS)

Haq, I.; Nawaz, A.; Mukhtar, A.N.H.; Mansoor, H.M.Z.; Ameer, S.M.

2014-01-01

The study deals with the improvement of wild strain Aspergillus niger IIB-31 through random mutagenesis using chemical mutagens. The main aim of the work was to enhance the glucose oxidase (GOX) yield of wild strain (24.57+-0.01 U/g of cell mass) through random mutagenesis and process optimization. The wild strain of Aspergillus niger IIB-31 was treated with chemical mutagens such as Ethyl methane sulphonate (EMS) and nitrous acid for this purpose. Mutagen treated 98 variants indicating the positive results were picked and screened for the glucose oxidase production using submerged fermentation. EMS treated E45 mutant strain gave the highest glucose oxidase production (69.47 + 0.01 U/g of cell mass), which was approximately 3-folds greater than the wild strain IIB-31. The preliminary cultural conditions for the production of glucose oxidase using submerged fermentation from strain E45 were also optimized. The highest yield of GOD was obtained using 8% glucose as carbon and 0.3% peptone as nitrogen source at a medium pH of 7.0 after an incubation period of 72 hrs at 30 degree. (author)

Modeling and optimizing of the random atomic spin gyroscope drift based on the atomic spin gyroscope

Energy Technology Data Exchange (ETDEWEB)

Quan, Wei; Lv, Lin, E-mail: lvlinlch1990@163.com; Liu, Baiqi [School of Instrument Science and Opto-Electronics Engineering, Beihang University, Beijing 100191 (China)

2014-11-15

In order to improve the atom spin gyroscope's operational accuracy and compensate the random error caused by the nonlinear and weak-stability characteristic of the random atomic spin gyroscope (ASG) drift, the hybrid random drift error model based on autoregressive (AR) and genetic programming (GP) + genetic algorithm (GA) technique is established. The time series of random ASG drift is taken as the study object. The time series of random ASG drift is acquired by analyzing and preprocessing the measured data of ASG. The linear section model is established based on AR technique. After that, the nonlinear section model is built based on GP technique and GA is used to optimize the coefficients of the mathematic expression acquired by GP in order to obtain a more accurate model. The simulation result indicates that this hybrid model can effectively reflect the characteristics of the ASG's random drift. The square error of the ASG's random drift is reduced by 92.40%. Comparing with the AR technique and the GP + GA technique, the random drift is reduced by 9.34% and 5.06%, respectively. The hybrid modeling method can effectively compensate the ASG's random drift and improve the stability of the system.

Intermittent Fasting Modulation of the Diabetic Syndrome in Streptozotocin-Injected Rats

Directory of Open Access Journals (Sweden)

Louiza Belkacemi

2012-01-01

Full Text Available This study investigates the effects of intermittent overnight fasting in streptozotocin-induced diabetic rats (STZ rats. Over 30 days, groups of 5-6 control or STZ rats were allowed free food access, starved overnight, or exposed to a restricted food supply comparable to that ingested by the intermittently fasting animals. Intermittent fasting improved glucose tolerance, increased plasma insulin, and lowered Homeostatis Model Assessment index. Caloric restriction failed to cause such beneficial effects. The β-cell mass, as well as individual β-cell and islet area, was higher in intermittently fasting than in nonfasting STZ rats, whilst the percentage of apoptotic β-cells appeared lower in the former than latter STZ rats. In the calorie-restricted STZ rats, comparable findings were restricted to individual islet area and percentage of apoptotic cells. Hence, it is proposed that intermittent fasting could represent a possible approach to prevent or minimize disturbances of glucose homeostasis in human subjects.

Intermittent Fasting Modulation of the Diabetic Syndrome in Streptozotocin-Injected Rats

OpenAIRE

Louiza Belkacemi; Ghalem Selselet-Attou; Emeline Hupkens; Evrard Nguidjoe; Karim Louchami; Abdullah Sener; Willy J. Malaisse

2012-01-01

This study investigates the effects of intermittent overnight fasting in streptozotocin-induced diabetic rats (STZ rats). Over 30 days, groups of 5-6 control or STZ rats were allowed free food access, starved overnight, or exposed to a restricted food supply comparable to that ingested by the intermittently fasting animals. Intermittent fasting improved glucose tolerance, increased plasma insulin, and lowered Homeostatis Model Assessment index. Caloric restriction failed to cause such benefic...

An intermittency route to global instability in low-density jets

Science.gov (United States)

Murugesan, Meenatchidevi; Zhu, Yuanhang; Li, Larry K. B.

2017-11-01

Above a critical Reynolds number (Re), a low-density jet can become globally unstable, transitioning from a steady state (i.e. a fixed point) to a self-excited oscillatory state (i.e. a limit cycle) via a Hopf bifurcation. In this experimental study, we show that this transition can sometimes involve intermittency. When Re is just slightly above the critical point, intermittent bursts of high-amplitude periodic oscillations emerge amidst a background of low-amplitude aperiodic fluctuations. As Re increases further, these intermittent bursts persist longer in time until they dominate the overall dynamics, causing the jet to transition fully to a periodic limit cycle. We identify this as Type-II Pomeau-Manneville intermittency by quantifying the statistical distribution of the duration of the aperiodic fluctuations at the onset of intermittency. This study shows that the transition to global instability in low-density jets is not always abrupt but can involve an intermediate state with characteristics of both the initial fixed point and the final limit cycle. This work was supported by the Research Grants Council of Hong Kong (Project No. 16235716 and 26202815).

Isolated intermittent vertigo: A presenting feature of persistent trigeminal artery

Directory of Open Access Journals (Sweden)

Rajsrinivas Parthasarathy

2016-01-01

Full Text Available Embryonic carotid – basilar anastomosis when persistent in adult life can present with a variety of neurological symptoms. We present a patient with isolated intermittent vertigo attributable to the embryonic anastomosis and describe the different types of persistent trigeminal artery. A 76-year-old Caucasian man presented with isolated intermittent vertigo and symptoms suggestive of anterior and posterior circulation strokes. Impaired vasomotor reactivity was demonstrated on insonation of the anterior and posterior cerebral arteries in this patient with a persistent left trigeminal artery and 75% stenosis of the left internal carotid artery (ICA. The symptom of intermittent vertigo resolved with carotid endarterectomy. Decreased flow across the stenotic segment of the ICA which subserved the posterior circulation resulted in basilar insufficiency. Hypoperfusion to the flocculonodular lobe supplied by the anterior inferior cerebellar artery is a likely cause for the intermittent vertigo.

The Effect of High-Intensity Intermittent Exercise on Body Composition of Overweight Young Males

Directory of Open Access Journals (Sweden)

M. Heydari

2012-01-01

Full Text Available To determine the effect of a 12-week high intensity intermittent exercise (HIIE intervention on total body, abdominal, trunk, visceral fat mass, and fat free mass of young overweight males. Participants were randomly assigned to either exercise or control group. The intervention group received HIIE three times per week, 20 min per session, for 12 weeks. Aerobic power improved significantly (P0.05 occurred in levels of insulin, HOMA-IR, and blood lipids. Twelve weeks of HIIE resulted in significant reductions in total, abdominal, trunk, and visceral fat and significant increases in fat free mass and aerobic power.

Modeling integrated water user decisions in intermittent supply systems

Science.gov (United States)

Rosenberg, David E.; Tarawneh, Tarek; Abdel-Khaleq, Rania; Lund, Jay R.

2007-07-01

We apply systems analysis to estimate household water use in an intermittent supply system considering numerous interdependent water user behaviors. Some 39 household actions include conservation; improving local storage or water quality; and accessing sources having variable costs, availabilities, reliabilities, and qualities. A stochastic optimization program with recourse decisions identifies the infrastructure investments and short-term coping actions a customer can adopt to cost-effectively respond to a probability distribution of piped water availability. Monte Carlo simulations show effects for a population of customers. Model calibration reproduces the distribution of billed residential water use in Amman, Jordan. Parametric analyses suggest economic and demand responses to increased availability and alternative pricing. It also suggests potential market penetration for conservation actions, associated water savings, and subsidies to entice further adoption. We discuss new insights to size, target, and finance conservation.

Effect of Intermittent Energy Restriction on Flow Mediated Dilatation, a Measure of Endothelial Function: A Short Report.

Science.gov (United States)

Headland, Michelle L; Clifton, Peter M; Keogh, Jennifer B

2018-06-04

Intermittent energy restriction is a popular alternative to daily energy restriction for weight loss; however, it is unknown if endothelial function, a risk factor for cardiovascular disease, is altered by periods of severe energy restriction. The objective of the study was to determine the impact of two consecutive very low energy intake days, which is the core component of the 5:2 intermittent energy restriction diet strategy, on endothelial function compared to consecutive ad libitum eating days. The secondary objective was to explore the effects of these dietary conditions on fasting glucose concentrations. This was a 4-week randomized, single-blinded, crossover study of 35 participants. Participants consumed a very low energy diet (500 calories for women, 600 calories for men) on two consecutive days per week and 5 days of habitual eating. In weeks 3 and 4 of the trial, participants had measurements of flow mediated dilatation (FMD) and blood samples taken following either 2 habitual eating days or 2 energy restricted days in a randomized order. FMD values were not different after the two eating states (8.6% vs. 8.3%, p = 0.7). All other outcome variables were unchanged. Endothelial function, as measured by flow mediated dilatation, was not altered by two consecutive very low energy intake days. Further investigations assessing the impact in specific population groups as well as different testing conditions would be beneficial.

Radial evolution of the intermittency of density fluctuations in the fast solar wind

International Nuclear Information System (INIS)

Bruno, R.; D'Amicis, R.; Telloni, D.; Primavera, L.; Sorriso-Valvo, L.; Carbone, V.; Malara, F.; Veltri, P.; Pietropaolo, E.

2014-01-01

We study the radial evolution of the intermittency of density fluctuations in the fast solar wind. The study is performed by analyzing the plasma density measurements provided by Helios 2 in the inner heliosphere between 0.3 and 0.9 AU. The analysis is carried out by means of a complete set of diagnostic tools, including the flatness factor at different timescales to estimate intermittency, the Kolmogorov-Smirnov test to estimate the degree of intermittency, and the Fourier transform to estimate the power spectral densities of these fluctuations. Density fluctuations within the fast wind are rather intermittent and their level of intermittency, together with the amplitude of intermittent events, decreases with the distance from the Sun, at odds with the intermittency of both magnetic field and all other plasma parameters. Furthermore, the intermittent events are strongly correlated, exhibiting temporal clustering. This indicates that the mechanism underlying their generation departs from a time-varying Poisson process. A remarkable, qualitative similarity with the behavior of plasma density fluctuations obtained from a numerical study of the nonlinear evolution of parametric instability in the solar wind supports the idea that this mechanism has an important role in governing density fluctuations in the inner heliosphere.

Study the Effect of Intermittent and Continuous Ponding Depths by Using Different Heads to Leach Water

OpenAIRE

Nesrin J. AL-Mansori

2018-01-01

As results of using water for irrigated lands in a random manner in a time of shortage main water resources, Experimental work carried out to study the effect of continuous and intermittent ponding depth on the leaching processes. Sandy soil used, sourced from Hilla / Al-Jameeya, at Hilla city. Sieve analysis and hydrometer testing used to identify the properties of the soil. A model used with dimensions of 30, 30 and, 70 cm, with two different heads of water. Shatt-Al-Hilla River samples use...

Sensitivity of intermittent streams to climate variations in the United States

Science.gov (United States)

Eng, K.

2015-12-01

There is growing interest in the effects of climate change on streamflows because of the potential negative effects on aquatic biota and water supplies. Previous studies of climate controls on flows have primarily focused on perennial streams, and few studies have examined the effect of climate variability on intermittent streams. Our objectives in this study were to (1) identify regions showing similar patterns of intermittency, and (2) evaluate the sensitivity of intermittent streams to historical variability in climate in the United States. This study was carried out at 265 intermittent streams by evaluating: (1) correlations among time series of flow metrics (number of zero-flow events, the average of the central 50% and largest 10% of flows) with precipitation (magnitudes, durations and intensity) and temperature, and (2) decadal changes in the seasonality and long-term trends of these flow metrics. Results identified five distinct seasonal patterns of flow intermittency: fall, fall-to-winter, non-seasonal, summer, and summer-to-winter intermittent streams. In addition, strong associations between the low-flow metrics and historical climate variability were found. However, the lack of trends in historical variations in precipitation results in no significant seasonal shifts or decade-to-decade trends in the low-flow metrics over the period of record (1950 to 2013).

An Optimization Scheduling Model for Wind Power and Thermal Power with Energy Storage System considering Carbon Emission Trading

Directory of Open Access Journals (Sweden)

Huan-huan Li

2015-01-01

Full Text Available Wind power has the characteristics of randomness and intermittence, which influences power system safety and stable operation. To alleviate the effect of wind power grid connection and improve power system’s wind power consumptive capability, this paper took emission trading and energy storage system into consideration and built an optimization model for thermal-wind power system and energy storage systems collaborative scheduling. A simulation based on 10 thermal units and wind farms with 2800 MW installed capacity verified the correctness of the models put forward by this paper. According to the simulation results, the introduction of carbon emission trading can improve wind power consumptive capability and cut down the average coal consumption per unit of power. The introduction of energy storage system can smooth wind power output curve and suppress power fluctuations. The optimization effects achieve the best when both of carbon emission trading and energy storage system work at the same time.

Multiparticle correlations and intermittency in high energy collisions

CERN Document Server

Bozek, P

1992-01-01

In this work the analysis of the intermittency signal observed in high energy experi- ments is done using multiparticle distributions and correlation functions. The effect of the dimensional projection of the multiparticle distributions on one or two-dimensional subspace is discussed. The structure of the multiparticle cumulants is analyzed for the DELPHI e + e~ annihilation data. The language of the self-similar distribution func- tions, which is used in this work, is shown to be largely equivalent to the well known a-model. In the case of the ultrarelativistic nuclear collisions, where the Monte-Carlo simulations fail to reproduce the data, we argue that the observed intermittency pattern is a signal of some nonlinear effect beyond the simple superposition of nucleon-nucleon collisions. The model of spatiotemporal intermittency is discussed in details and is shown to reproduce qualitatively the dependence of t...

Stochastic Modeling and Optimization in a Microgrid: A Survey

Directory of Open Access Journals (Sweden)

Hao Liang

2014-03-01

Full Text Available The future smart grid is expected to be an interconnected network of small-scale and self-contained microgrids, in addition to a large-scale electric power backbone. By utilizing microsources, such as renewable energy sources and combined heat and power plants, microgrids can supply electrical and heat loads in local areas in an economic and environment friendly way. To better adopt the intermittent and weather-dependent renewable power generation, energy storage devices, such as batteries, heat buffers and plug-in electric vehicles (PEVs with vehicle-to-grid systems can be integrated in microgrids. However, significant technical challenges arise in the planning, operation and control of microgrids, due to the randomness in renewable power generation, the buffering effect of energy storage devices and the high mobility of PEVs. The two-way communication functionalities of the future smart grid provide an opportunity to address these challenges, by offering the communication links for microgrid status information collection. However, how to utilize stochastic modeling and optimization tools for efficient, reliable and economic planning, operation and control of microgrids remains an open issue. In this paper, we investigate the key features of microgrids and provide a comprehensive literature survey on the stochastic modeling and optimization tools for a microgrid. Future research directions are also identified.

Comparison of Clenshaw–Curtis and Leja Quasi-Optimal Sparse Grids for the Approximation of Random PDEs

KAUST Repository

Nobile, Fabio

2015-11-26

In this work we compare different families of nested quadrature points, i.e. the classic Clenshaw–Curtis and various kinds of Leja points, in the context of the quasi-optimal sparse grid approximation of random elliptic PDEs. Numerical evidence suggests that both families perform comparably within such framework.

On-line intermittent connector anomaly detection

Data.gov (United States)

National Aeronautics and Space Administration — This paper investigates a non-traditional use of differential current sensor and current sensor to detect intermittent disconnection problems in connectors. An...

Scaling the Thrust Production and Energetics of Inviscid Intermittent Swimming

Science.gov (United States)

Akoz, Emre; Moored, Keith

2015-11-01

Many fish have adopted an intermittent swimming gait sometimes referred as a burst-and-coast behavior. By using this gait, fish have been estimated at reducing their energetic cost of swimming by about 50%. Lighthill proposed that the skin friction drag of an undulating body can be around 400% greater than a rigidly-held coasting body, which may explain the energetic savings of intermittent swimming. Recent studies have confirmed the increase in skin friction drag over an undulating body, however, the increase is on the order of 20-70%. This more modest gain in skin friction drag is not sufficient to lead to the observed energy savings. Motivated by these observations, we investigate the inviscid mechanisms behind intermittent swimming for parameters typical of biology. We see that there is an energy savings at a fixed swimming speed for intermittent swimming as compared to continuous swimming. Then we consider three questions: What is the nature of the inviscid mechanism that leads to the observed energy savings, how do the forces and energetics of intermittent swimming scale with the swimming parameters, and what are the limitations to the benefit? Supported by the Office of Naval Research under Program Director Dr. Bob Brizzola, MURI grant number N00014-14-1-0533.

Stochastic reactive power dispatch in hybrid power system with intermittent wind power generation

International Nuclear Information System (INIS)

Taghavi, Reza; Seifi, Ali Reza; Samet, Haidar

2015-01-01

Environmental concerns besides fuel costs are the predominant reasons for unprecedented escalating integration of wind turbine on power systems. Operation and planning of power systems are affected by this type of energy due to the intermittent nature of wind speed inputs with high uncertainty in the optimization output variables. Consequently, in order to model this high inherent uncertainty, a PRPO (probabilistic reactive power optimization) framework should be devised. Although MC (Monte-Carlo) techniques can solve the PRPO with high precision, PEMs (point estimate methods) can preserve the accuracy to attain reasonable results when diminishing the computational effort. Also, this paper introduces a methodology for optimally dispatching the reactive power in the transmission system, while minimizing the active power losses. The optimization problem is formulated as a LFP (linear fuzzy programing). The core of the problem lay on generation of 2m + 1 point estimates for solving PRPO, where n is the number of input stochastic variables. The proposed methodology is investigated using the IEEE-14 bus test system equipped with HVDC (high voltage direct current), UPFC (unified power flow controller) and DFIG (doubly fed induction generator) devices. The accuracy of the method is demonstrated in the case study. - Highlights: • This paper uses stochastic loads in optimization process. • AC–DC load flow is modified to use some advantages of DC part in optimization process. • UPFC and DFIG are simulated in a way that could be effective in optimization process. • Fuzzy set has been used as an uncertainty analysis tool in the optimization

Intermittent versus Continuous Physiotherapy in Children with Cerebral Palsy

Science.gov (United States)

Christiansen, Annette Sandahl; Lange, Christa

2008-01-01

The aim of this study was to compare the effect of the delivery of the same amount of intermittent versus continuous physiotherapy given to children with cerebral palsy (CP). This was organized either in an intermittent regime four times a week for 4 weeks alternating with a 6-week treatment pause, or a continuous once or twice a week regime, both…

Intermittent Hypoxia Alters Gene Expression in Peripheral Blood Mononuclear Cells of Healthy Volunteers.

Science.gov (United States)

Polotsky, Vsevolod Y; Bevans-Fonti, Shannon; Grigoryev, Dmitry N; Punjabi, Naresh M

2015-01-01

Obstructive sleep apnea is associated with high cardiovascular morbidity and mortality. Intermittent hypoxia of obstructive sleep apnea is implicated in the development and progression of insulin resistance and atherosclerosis, which have been attributed to systemic inflammation. Intermittent hypoxia leads to pro-inflammatory gene up-regulation in cell culture, but the effects of intermittent hypoxia on gene expression in humans have not been elucidated. A cross-over study was performed exposing eight healthy men to intermittent hypoxia or control conditions for five hours with peripheral blood mononuclear cell isolation before and after exposures. Total RNA was isolated followed by gene microarrays and confirmatory real time reverse transcriptase PCR. Intermittent hypoxia led to greater than two fold up-regulation of the pro-inflammatory gene toll receptor 2 (TLR2), which was not increased in the control exposure. We hypothesize that up-regulation of TLR2 by intermittent hypoxia may lead to systemic inflammation, insulin resistance and atherosclerosis in patients with obstructive sleep apnea.

Obstructive sleep apnea and cancer: effects of intermittent hypoxia?

Science.gov (United States)

Kukwa, Wojciech; Migacz, Ewa; Druc, Karolina; Grzesiuk, Elzbieta; Czarnecka, Anna M

2015-01-01

Obstructive sleep apnea (OSA) is a common disorder characterized by pauses in regular breathing. Apneic episodes lead to recurrent hypoxemia-reoxygenation cycles with concomitant cellular intermittent hypoxia. Studies suggest that intermittent hypoxia in OSA may influence tumorigenesis. This review presents recent articles on the potential role of OSA in cancer development. Relevant research has focused on: molecular pathways mediating the influence of intermittent hypoxia on tumor physiology, animal and epidemiological human studies linking OSA and cancer. Current data relating OSA to risk of neoplastic disease remain scarce, but recent studies reveal the potential for a strong relation. More work is, therefore, needed on the impact of OSA on many cancer-related aspects. Results may offer enlightenment for improved cancer diagnosis and treatment.

High rates of parasite recrudescence following intermittent preventive treatment with sulphadoxine-pyrimethamine during pregnancy in Benin

DEFF Research Database (Denmark)

Moussiliou, Azizath; Sissinto-Savi De Tove, Yolande; Doritchamou, Justin

2013-01-01

the second dose. Women with persistent parasitaemia had an increased prevalence of anaemia (P = 0.03). CONCLUSION: The data presented here, highlight the inability of SP to ensure optimal antiplasmodial protection in late pregnancy, and invite urgent consideration of an alternative drug or strategy.......BACKGROUND: Despite widespread parasite resistance to sulphadoxine-pyrimethamine (SP) its use for intermittent preventative treatment during pregnancy remains the policy in Benin and throughout most of sub-Saharan Africa. METHODS: In a prospective study, 982 pregnant women were recruited in Benin...

Shape of power spectrum of intermittent chaos

International Nuclear Information System (INIS)

So, B.C.; Mori, H.

1984-01-01

Power spectra of intermittent chaos are calculated analytically. It is found that the power spectrum near onset point consists of a large number of Lorentzian lines with two peaks around frequencies ω = 0 and ω = ω 0 , where ω 0 is a fundamental frequency of a periodic orbit before the onset point, and furthermore the envelope of lines around ω = 0 obeys the power law 1/ + ω +2 , whereas the envelope around ω 0 obeys 1/ + ω-ω 0 +4 . The universality of these power law dependence in a certain class of intermittent chaos are clarified from a phenomenological view point. (author)

Critical behavior of the Lyapunov exponent in type-III intermittency

Energy Technology Data Exchange (ETDEWEB)

Alvarez-Llamoza, O. [Departamento de Fisica, FACYT, Universidad de Carabobo, Valencia (Venezuela); Centro de Fisica Fundamental, Grupo de Caos y Sistemas Complejos, Universidad de Los Andes, Merida 5251, Merida (Venezuela)], E-mail: llamoza@ula.ve; Cosenza, M.G. [Centro de Fisica Fundamental, Grupo de Caos y Sistemas Complejos, Universidad de Los Andes, Merida 5251, Merida (Venezuela); Ponce, G.A. [Departamento de Fisica, Universidad Nacional Autonoma de Honduras (Honduras); Departamento de Ciencias Naturales, Universidad Pedagogica Nacional Francisco Morazan, Tegucigalpa (Honduras)

2008-04-15

The critical behavior of the Lyapunov exponent near the transition to robust chaos via type-III intermittency is determined for a family of one-dimensional singular maps. Critical boundaries separating the region of robust chaos from the region where stable fixed points exist are calculated on the parameter space of the system. A critical exponent {beta} expressing the scaling of the Lyapunov exponent is calculated along the critical curve corresponding to the type-III intermittent transition to chaos. It is found that {beta} varies on the interval 0 {<=} {beta} < 1/2 as a function of the order of the singularity of the map. This contrasts with earlier predictions for the scaling behavior of the Lyapunov exponent in type-III intermittency. The variation of the critical exponent {beta} implies a continuous change in the nature of the transition to chaos via type-III intermittency, from a second-order, continuous transition to a first-order, discontinuous transition.

Critical behavior of the Lyapunov exponent in type-III intermittency

International Nuclear Information System (INIS)

Alvarez-Llamoza, O.; Cosenza, M.G.; Ponce, G.A.

2008-01-01

The critical behavior of the Lyapunov exponent near the transition to robust chaos via type-III intermittency is determined for a family of one-dimensional singular maps. Critical boundaries separating the region of robust chaos from the region where stable fixed points exist are calculated on the parameter space of the system. A critical exponent β expressing the scaling of the Lyapunov exponent is calculated along the critical curve corresponding to the type-III intermittent transition to chaos. It is found that β varies on the interval 0 ≤ β < 1/2 as a function of the order of the singularity of the map. This contrasts with earlier predictions for the scaling behavior of the Lyapunov exponent in type-III intermittency. The variation of the critical exponent β implies a continuous change in the nature of the transition to chaos via type-III intermittency, from a second-order, continuous transition to a first-order, discontinuous transition

Intermittently chaotic oscillations for a differential-delay equation with Gaussian nonlinearity

Science.gov (United States)

Hamilton, Ian

1992-01-01

For a differential-delay equation the time dependence of the variable is a function of the variable at a previous time. We consider a differential-delay equation with Gaussian nonlinearity that displays intermittent chaos. Although not the first example of a differential-delay equation that displays such behavior, for this example the intermittency is classified as type III, and the origin of the intermittent chaos may be qualitatively understood from the limiting forms of the equation for large and small variable magnitudes.

A community-based delivery system of intermittent preventive treatment of malaria in pregnancy and its effect on use of essential maternity care at health units in Uganda

DEFF Research Database (Denmark)

Mbonye, Anthony K; Bygbjerg, I C; Magnussen, Pascal

2007-01-01

Community delivery of intermittent preventive treatment of malaria in pregnancy (IPTp) is one potential option that could mitigate malaria in pregnancy. However, there is concern that this approach may lead to complacency among women with low access to essential care at health units. A non-random...

Intermittency and multifractional Brownian character of geomagnetic time series

Directory of Open Access Journals (Sweden)

G. Consolini

2013-07-01

Full Text Available The Earth's magnetosphere exhibits a complex behavior in response to the solar wind conditions. This behavior, which is described in terms of mutifractional Brownian motions, could be the consequence of the occurrence of dynamical phase transitions. On the other hand, it has been shown that the dynamics of the geomagnetic signals is also characterized by intermittency at the smallest temporal scales. Here, we focus on the existence of a possible relationship in the geomagnetic time series between the multifractional Brownian motion character and the occurrence of intermittency. In detail, we investigate the multifractional nature of two long time series of the horizontal intensity of the Earth's magnetic field as measured at L'Aquila Geomagnetic Observatory during two years (2001 and 2008, which correspond to different conditions of solar activity. We propose a possible double origin of the intermittent character of the small-scale magnetic field fluctuations, which is related to both the multifractional nature of the geomagnetic field and the intermittent character of the disturbance level. Our results suggest a more complex nature of the geomagnetic response to solar wind changes than previously thought.

Physiologic basis for intermittent hypoxic episodes in preterm infants.

Science.gov (United States)

Martin, R J; Di Fiore, J M; Macfarlane, P M; Wilson, C G

2012-01-01

Intermittent hypoxic episodes are typically a consequence of immature respiratory control and remain a troublesome challenge for the neonatologist. Furthermore, their frequency and magnitude are commonly underestimated by clinically employed pulse oximeter settings. In extremely low birth weight infants the incidence of intermittent hypoxia [IH] progressively increases over the first 4 weeks of postnatal life, with a subsequent plateau followed by a slow decline beginning at weeks six to eight. Over this period of unstable respiratory control, increased oxygen-sensitive peripheral chemoreceptor activity has been associated with a higher incidence of apnea of prematurity. In contrast, infants with bronchopulmonary dysplasia [chronic neonatal lung disease] exhibit decreased peripheral chemosensitivity, although the effect on respiratory stability in this population is unclear. Such episodic hypoxia/reoxygenation in early life has the potential to sustain a proinflammatory cascade with resultant multisystem, including respiratory, morbidity. Therapeutic approaches for intermittent hypoxic episodes comprise careful titration of baseline or supplemental inspired oxygen as well as xanthine therapy to prevent apnea of prematurity. Characterization of the pathophysiologic basis for such intermittent hypoxic episodes and their consequences during early life is necessary to provide an evidence-based approach to their management.

Tuning of an optimal fuzzy PID controller with stochastic algorithms for networked control systems with random time delay.

Science.gov (United States)

Pan, Indranil; Das, Saptarshi; Gupta, Amitava

2011-01-01

An optimal PID and an optimal fuzzy PID have been tuned by minimizing the Integral of Time multiplied Absolute Error (ITAE) and squared controller output for a networked control system (NCS). The tuning is attempted for a higher order and a time delay system using two stochastic algorithms viz. the Genetic Algorithm (GA) and two variants of Particle Swarm Optimization (PSO) and the closed loop performances are compared. The paper shows that random variation in network delay can be handled efficiently with fuzzy logic based PID controllers over conventional PID controllers. Copyright © 2010 ISA. Published by Elsevier Ltd. All rights reserved.

Intermittent balneotherapy at the Dead Sea area for patients with knee osteoarthritis.

Science.gov (United States)

Sherman, Gilad; Zeller, Lior; Avriel, Avital; Friger, Michael; Harari, Marco; Sukenik, Shaul

2009-02-01

Balneotherapy, traditionally administered during a continuous stay at the Dead Sea area, has been shown to be effective for patients suffering from knee osteoarthritis. To evaluate the effectiveness of an intermittent regimen of balneotherapy at the Dead Sea for patients with knee osteoarthritis. Forty-four patients with knee osteoarthritis were included in a prospective randomized single-blind controlled study. The patients were divided into two groups: a treatment group (n=24), which were treated twice weekly for 6 consecutive weeks in a sulfur pool heated to 35-36 degrees C, and a control group (n=20) treated in a Jacuzzi filled with tap water heated to 35-36 degrees C. Participants were assessed by the Lequesne index of osteoarthritis severity, the WOMAC index, the SF-36 quality of health questionnaire, VAS scales for pain (completed by patients and physicians), and physical examination. A statistically significant improvement, lasting up to 6 months, was observed in the treatment group for most of the clinical parameters. In the control group the only improvements were in the SF-36 bodily pain scale at 6 months, the Lequesne index at 1 month and the WOMAC pain score at the end of the treatment period. Although the patients in the control group had milder disease, the difference between the two groups was not statistically significant. Intermittent balneotherapy appears to be effective for patients with knee osteoarthritis.

The effect of intense intermittent training with and without taking vitamin E on mRNA expression of p53/PTEN tumor suppressing genes in prostate glands of male rats

Directory of Open Access Journals (Sweden)

Mohammad Esmaeil Afzalpour

2016-11-01

Full Text Available Physical activity and diet are the most important modifiable determinants of cancer risk. The objective of this study was to examine the effect of intense intermittent training with and without taking vitamin E on expression of p53 and PTEN tumor suppressing genes in the prostate gland of male rats. For this purpose, 50 Sprague-Dawley male rats were randomly assigned into 5 groups: [1] control (CON, n = 10, [2] sham (S, n = 10, [3] intense intermittent training (IIT, n = 10, [4] intense intermittent training + vitamin E (IIT + VE, n = 10, [5] vitamin E (VE, n = 10. Protocol of this study was implemented for 6 days per week for 6 weeks, with observing the overload principle on the motorized treadmill. After implementing training protocol, expression rate of p53 and PTEN genes reduced significantly (p<0.000, p<0.031, respectively. Taking vitamin E with intermittent training caused significant reduction in p53 expression (p<0.013, while it caused significant increase in expression of PTEN (p<0.035. These results showed that intense intermittent training reduces expression of p53 and PTEN tumor suppressing genes and taking supplementation vitamin E along with this type of training could cause different effects in expression of these tumor suppressor genes.

Intermittent Anisotropic Turbulence Detected by THEMIS in the Magnetosheath

Science.gov (United States)

Macek, W. M.; Wawrzaszek, A.; Kucharuk, B.; Sibeck, D. G.

2017-12-01

Following our previous study of Time History of Events and Macroscale Interactions during Substorms (THEMIS) data, we consider intermittent turbulence in the magnetosheath depending on various conditions of the magnetized plasma behind the Earth’s bow shock and now also near the magnetopause. Namely, we look at the fluctuations of the components of the Elsässer variables in the plane perpendicular to the scale-dependent background magnetic fields and along the local average ambient magnetic fields. We have shown that Alfvén fluctuations often exhibit strong anisotropic non-gyrotropic turbulent intermittent behavior resulting in substantial deviations of the probability density functions from a normal Gaussian distribution with a large kurtosis. In particular, for very high Alfvénic Mach numbers and high plasma beta, we have clear anisotropy with non-Gaussian statistics in the transverse directions. However, along the magnetic field, the kurtosis is small and the plasma is close to equilibrium. On the other hand, intermittency becomes weaker for moderate Alfvén Mach numbers and lower values of the plasma parameter beta. It also seems that the degree of intermittency of turbulence for the outgoing fluctuations propagating relative to the ambient magnetic field is usually similar as for the ingoing fluctuations, which is in agreement with approximate equipartition of energy between these oppositely propagating Alfvén waves. We believe that the different characteristics of this intermittent anisotropic turbulent behavior in various regions of space and astrophysical plasmas can help identify nonlinear structures responsible for deviations of the plasma from equilibrium.

Optimal Policies for Random and Periodic Garbage Collections with Tenuring Threshold

Science.gov (United States)

Zhao, Xufeng; Nakamura, Syouji; Nakagawa, Toshio

It is an important problem to determine the tenuring threshold to meet the pause time goal for a generational garbage collector. From such viewpoint, this paper proposes two stochastic models based on the working schemes of a generational garbage collector: One is random collection which occurs at a nonhomogeneous Poisson process and the other is periodic collection which occurs at periodic times. Since the cost suffered for minor collection increases, as the amount of surviving objects accumulates, tenuring minor collection should be made at some tenuring threshold. Using the techniques of cumulative processes and reliability theory, expected cost rates with tenuring threshold are obtained, and optimal policies which minimize them are discussed analytically and computed numerically.

Wave-Number Spectra and Intermittency in the Terrestrial Foreshock Region

International Nuclear Information System (INIS)

Narita, Y.; Glassmeier, K.-H.; Treumann, R. A.

2006-01-01

Wave-number spectra of magnetic field fluctuations are directly determined in the terrestrial foreshock region (upstream of a quasiparallel collisionless shock wave) using four-point Cluster spacecraft measurements. The spectral curve is characterized by three ranges reminiscent of turbulence: energy injection, inertial, and dissipation range. The spectral index for the inertial range spectrum is close to Kolmogorov's slope, -5/3. On the other hand, the fluctuations are highly anisotropic and intermittent perpendicular to the mean magnetic field direction. These results suggest that the foreshock is in a weakly turbulent and intermittent state in which parallel propagating Alfven waves interact with one another, resulting in the phase coherence or the intermittency

Enhancement of Intermittent Androgen Ablation Therapy by Finasteride Administration in Animal Models

National Research Council Canada - National Science Library

Wang, Zhou

2004-01-01

.... Intermittent androgen ablation therapy may slow down the development of androgen refractory tumors because intermittent recovery of androgens can induce differentiation of prostatic epithelial cells...

Enhancement of Intermittent Androgen Ablation Therapy by Finasteride Administration in Animal Models

National Research Council Canada - National Science Library

Wang, Zhou

2005-01-01

.... Intermittent androgen ablation therapy may slow down the development of androgen refractory tumors because intermittent recovery of androgens can induce differentiation of prostatic epithelial cells...

Enhancement of Intermittent Androgen Ablation Therapy by Finasteride Administration in Animal Models

National Research Council Canada - National Science Library

Wang, Zhou

2003-01-01

.... Intermittent androgen ablation therapy may slow down the development of androgen refractory tumors because intermittent recovery of androgens can induce differentiation of prostatic epithelial cells...

Defining the Optimal Dietary Approach for Safe, Effective and Sustainable Weight Loss in Overweight and Obese Adults

Directory of Open Access Journals (Sweden)

Chrysi Koliaki

2018-06-01

Full Text Available Various dietary approaches with different caloric content and macronutrient composition have been recommended to treat obesity in adults. Although their safety and efficacy profile has been assessed in numerous randomized clinical trials, reviews and meta-analyses, the characteristics of the optimal dietary weight loss strategy remain controversial. This mini-review will provide general principles and practical recommendations for the dietary management of obesity and will further explore the components of the optimal dietary intervention. To this end, various dietary plans are critically discussed, including low-fat diets, low-carbohydrate diets, high-protein diets, very low-calorie diets with meal replacements, Mediterranean diet, and diets with intermittent energy restriction. As a general principle, the optimal diet to treat obesity should be safe, efficacious, healthy and nutritionally adequate, culturally acceptable and economically affordable, and should ensure long-term compliance and maintenance of weight loss. Setting realistic goals for weight loss and pursuing a balanced dietary plan tailored to individual needs, preferences, and medical conditions, are the key principles to facilitate weight loss in obese patients and most importantly reduce their overall cardiometabolic risk and other obesity-related comorbidities.

Interspinous process device versus standard conventional surgical decompression for lumbar spinal stenosis: Randomized controlled trial

NARCIS (Netherlands)

W.A. Moojen (Wouter); M.P. Arts (Mark); W.C.H. Jacobs (Wilco); E.W. van Zwet (Erik); M.E. van den Akker-van Marle (Elske); B.W. Koes (Bart); C.L.A.M. Vleggeert-Lankamp (Carmen); W.C. Peul (Wilco)

2013-01-01

markdownabstractAbstract Objective To assess whether interspinous process device implantation is more effective in the short term than conventional surgical decompression for patients with intermittent neurogenic claudication due to lumbar spinal stenosis. Design Randomized controlled

Intermittent Lagrangian velocities and accelerations in three-dimensional porous medium flow.

Science.gov (United States)

Holzner, M; Morales, V L; Willmann, M; Dentz, M

2015-07-01

Intermittency of Lagrangian velocity and acceleration is a key to understanding transport in complex systems ranging from fluid turbulence to flow in porous media. High-resolution optical particle tracking in a three-dimensional (3D) porous medium provides detailed 3D information on Lagrangian velocities and accelerations. We find sharp transitions close to pore throats, and low flow variability in the pore bodies, which gives rise to stretched exponential Lagrangian velocity and acceleration distributions characterized by a sharp peak at low velocity, superlinear evolution of particle dispersion, and double-peak behavior in the propagators. The velocity distribution is quantified in terms of pore geometry and flow connectivity, which forms the basis for a continuous-time random-walk model that sheds light on the observed Lagrangian flow and transport behaviors.

Response of Preterm Infants to 2 Noninvasive Ventilatory Support Systems: Nasal CPAP and Nasal Intermittent Positive-Pressure Ventilation.

Science.gov (United States)

Silveira, Carmen Salum Thomé; Leonardi, Kamila Maia; Melo, Ana Paula Carvalho Freire; Zaia, José Eduardo; Brunherotti, Marisa Afonso Andrade

2015-12-01

Noninvasive ventilation (NIV) in preterm infants is currently applied using intermittent positive pressure (2 positive-pressure levels) or in a conventional manner (one pressure level). However, there are no studies in the literature comparing the chances of failure of these NIV methods. The aim of this study was to evaluate the occurrence of failure of 2 noninvasive ventilatory support systems in preterm neonates over a period of 48 h. A randomized, prospective, clinical study was conducted on 80 newborns (gestational age CPAP and 40 infants with nasal intermittent positive-pressure ventilation (NIPPV). The occurrence of apnea, progression of respiratory distress, nose bleeding, and agitation was defined as ventilation failure. The need for intubation and re-intubation after failure was also observed. There were no significant differences in birth characteristics between groups. Ventilatory support failure was observed in 25 (62.5%) newborns treated with nasal CPAP and in 12 (30%) newborns treated with NIPPV, indicating an association between NIV failure and the absence of intermittent positive pressure (odds ratio [OR] 1.22, P CPAP failure. After failure, 25% (OR 0.33) of the newborns receiving nasal CPAP and 12.5% (OR 0.14) receiving NIPPV required invasive mechanical ventilation. Ventilatory support failure was significantly more frequent when nasal CPAP was used. Copyright © 2015 by Daedalus Enterprises.

New advances on chaotic intermittency and its applications

CERN Document Server

Elaskar, Sergio

2017-01-01

One of the most important routes to chaos is the chaotic intermittency. However, there are many cases that do not agree with the classical theoretical predictions. In this book, an extended theory for intermittency in one-dimensional maps is presented. A new general methodology to evaluate the reinjection probability density function (RPD) is developed in Chapters 5 to 8. The key of this formulation is the introduction of a new function, called M(x), which is used to calculate the RPD function. The function M(x) depends on two integrals. This characteristic reduces the influence on the statistical fluctuations in the data series. Also, the function M(x) is easy to evaluate from the data series, even for a small number of numerical or experimental data. As a result, a more general form for the RPD is found; where the classical theory based on uniform reinjection is recovered as a particular case. The characteristic exponent traditionally used to characterize the intermittency type, is now a function depending ...

Multiparticle correlations and intermittency in high energy collisions

International Nuclear Information System (INIS)

Bozek, P.

1992-01-01

The analysis of the intermittency signal observed in high energy experiments is presented using multiparticle distributions and correlation functions. The effect of the dimensional projection of the multiparticle distributions on one or two-dimensional subspace is discussed. The structure of the multiparticle cumulants is analyzed for the DELPHI e + e - annihilation data. The model of spatiotemporal intermittency is discussed in details and is shown to reproduce qualitatively the dependence of the intermittency strength on the target and projectile nuclei. A 1-dimensional (1D) cellular-automaton and a 1D forest-fire model is studied. On the example of the noncritical 1D Ising model the difficulties of the scaled factorial moment (SFM) method in extracting genuine scaling behaviour is illustrated. All these studies could serve as tools to test the sensibility of the SFM method as used in the analysis of the high energy production. (K.A.) 122 refs.; 38 figs.; 3 tabs

Multiparticle correlations and intermittency in high energy collisions

International Nuclear Information System (INIS)

Bozek, P.

1992-01-01

An analysis of the intermittency signal observed in high energy experiments is presented using multiparticle distributions and correlation functions. The effect of the dimensional projection of the multiparticle distributions on one or two-dimensional subspace is discussed. The structure of the multiparticle cumulants is analyzed for the DELPHI e + e - annihilation data. The model of spatiotemporal intermittency is discussed in details and is shown to reproduce qualitatively the dependence of the intermittency strength on the target and projectile nuclei. A 1-dimensional (lD) cellular-automaton (CA) and a lD forest-fire model is studied. On the example of the noncritical lD Ising model the difficulties of the scaled factorial moment (SFM) method in extracting genuine scaling behaviour are illustrated. The problem of the finite-size effect in connection to the dimensional projection can be easily exemplified in the case of the 2D critical system with conformal symmetry. (R.P.) 122 refs., 38 figs., 3 tabs

Using rapidly-exploring random tree-based algorithms to find smooth and optimal trajectories

CSIR Research Space (South Africa)

Matebese, B

2012-10-01

Full Text Available -exploring random tree-based algorithms to fi nd smooth and optimal trajectories B MATEBESE1, MK BANDA2 AND S UTETE1 1CSIR Modelling and Digital Science, PO Box 395, Pretoria, South Africa, 0001 2Department of Applied Mathematics, Stellenbosch University... and complex environments. The RRT algorithm is the most popular and has the ability to find a feasible solution faster than other algorithms. The drawback of using RRT is that, as the number of samples increases, the probability that the algorithm converges...

Stochastic optimization methods

CERN Document Server

Marti, Kurt

2005-01-01

Optimization problems arising in practice involve random parameters. For the computation of robust optimal solutions, i.e., optimal solutions being insensitive with respect to random parameter variations, deterministic substitute problems are needed. Based on the distribution of the random data, and using decision theoretical concepts, optimization problems under stochastic uncertainty are converted into deterministic substitute problems. Due to the occurring probabilities and expectations, approximative solution techniques must be applied. Deterministic and stochastic approximation methods and their analytical properties are provided: Taylor expansion, regression and response surface methods, probability inequalities, First Order Reliability Methods, convex approximation/deterministic descent directions/efficient points, stochastic approximation methods, differentiation of probability and mean value functions. Convergence results of the resulting iterative solution procedures are given.

Intermittency as a universal characteristic of the complete chromosome DNA sequences of eukaryotes: From protozoa to human genomes

Science.gov (United States)

Rybalko, S.; Larionov, S.; Poptsova, M.; Loskutov, A.

2011-10-01

Large-scale dynamical properties of complete chromosome DNA sequences of eukaryotes are considered. Using the proposed deterministic models with intermittency and symbolic dynamics we describe a wide spectrum of large-scale patterns inherent in these sequences, such as segmental duplications, tandem repeats, and other complex sequence structures. It is shown that the recently discovered gene number balance on the strands is not of a random nature, and certain subsystems of a complete chromosome DNA sequence exhibit the properties of deterministic chaos.

Enhancement of Intermittent Androgen Ablation Therapy by Finasteride Administration in Animal Models

National Research Council Canada - National Science Library

Wang, Zhou

2006-01-01

.... Intermittent androgen ablation therapy (IAAT) may slow down the development of androgen refractory tumors because intermittent recovery of androgens can induce differentiation of prostatic epithelial cells...

Intermittency in Hall-magnetohydrodynamics with a strong guide field

International Nuclear Information System (INIS)

Rodriguez Imazio, P.; Martin, L. N.; Dmitruk, P.; Mininni, P. D.

2013-01-01

We present a detailed study of intermittency in the velocity and magnetic field fluctuations of compressible Hall-magnetohydrodynamic turbulence with an external guide field. To solve the equations numerically, a reduced model valid when a strong guide field is present is used. Different values for the ion skin depth are considered in the simulations. The resulting data are analyzed computing field increments in several directions perpendicular to the guide field, and building structure functions and probability density functions. In the magnetohydrodynamic limit, we recover the usual results with the magnetic field being more intermittent than the velocity field. In the presence of the Hall effect, field fluctuations at scales smaller than the ion skin depth show a substantial decrease in the level of intermittency, with close to monofractal scaling

Chronic intermittent fasting improves cognitive functions and brain structures in mice.

Directory of Open Access Journals (Sweden)

Liaoliao Li

Full Text Available Obesity is a major health issue. Obesity started from teenagers has become a major health concern in recent years. Intermittent fasting increases the life span. However, it is not known whether obesity and intermittent fasting affect brain functions and structures before brain aging. Here, we subjected 7-week old CD-1 wild type male mice to intermittent (alternate-day fasting or high fat diet (45% caloric supplied by fat for 11 months. Mice on intermittent fasting had better learning and memory assessed by the Barnes maze and fear conditioning, thicker CA1 pyramidal cell layer, higher expression of drebrin, a dendritic protein, and lower oxidative stress than mice that had free access to regular diet (control mice. Mice fed with high fat diet was obese and with hyperlipidemia. They also had poorer exercise tolerance. However, these obese mice did not present significant learning and memory impairment or changes in brain structures or oxidative stress compared with control mice. These results suggest that intermittent fasting improves brain functions and structures and that high fat diet feeding started early in life does not cause significant changes in brain functions and structures in obese middle-aged animals.

Pulsar wind model for the spin-down behavior of intermittent pulsars

Energy Technology Data Exchange (ETDEWEB)

Li, L.; Tong, H.; Yan, W. M.; Yuan, J. P.; Wang, N. [Xinjiang Astronomical Observatory, Chinese Academy of Sciences, Urumqi, Xinjiang 830011 (China); Xu, R. X., E-mail: tonghao@xao.ac.cn [School of Physics, Peking University, Beijing (China)

2014-06-10

Intermittent pulsars are part-time radio pulsars. They have higher slow down rates in the on state (radio-loud) than in the off state (radio-quiet). This gives evidence that particle wind may play an important role in pulsar spindown. The effect of particle acceleration is included in modeling the rotational energy loss rate of the neutron star. Applying the pulsar wind model to the three intermittent pulsars (PSR B1931+24, PSR J1841–0500, and PSR J1832+0029) allows their magnetic fields and inclination angles to be calculated simultaneously. The theoretical braking indices of intermittent pulsars are also given. In the pulsar wind model, the density of the particle wind can always be the Goldreich-Julian density. This may ensure that different on states of intermittent pulsars are stable. The duty cycle of particle wind can be determined from timing observations. It is consistent with the duty cycle of the on state. Inclination angle and braking index observations of intermittent pulsars may help to test different models of particle acceleration. At present, the inverse Compton scattering induced space charge limited flow with field saturation model can be ruled out.

Chronic intermittent fasting improves cognitive functions and brain structures in mice.

Science.gov (United States)

Li, Liaoliao; Wang, Zhi; Zuo, Zhiyi

2013-01-01

Obesity is a major health issue. Obesity started from teenagers has become a major health concern in recent years. Intermittent fasting increases the life span. However, it is not known whether obesity and intermittent fasting affect brain functions and structures before brain aging. Here, we subjected 7-week old CD-1 wild type male mice to intermittent (alternate-day) fasting or high fat diet (45% caloric supplied by fat) for 11 months. Mice on intermittent fasting had better learning and memory assessed by the Barnes maze and fear conditioning, thicker CA1 pyramidal cell layer, higher expression of drebrin, a dendritic protein, and lower oxidative stress than mice that had free access to regular diet (control mice). Mice fed with high fat diet was obese and with hyperlipidemia. They also had poorer exercise tolerance. However, these obese mice did not present significant learning and memory impairment or changes in brain structures or oxidative stress compared with control mice. These results suggest that intermittent fasting improves brain functions and structures and that high fat diet feeding started early in life does not cause significant changes in brain functions and structures in obese middle-aged animals.

Enhancing wastewater degradation and biogas production by intermittent operation of UASB reactors

International Nuclear Information System (INIS)

Nadais, Helena; Barbosa, Marta; Capela, Isabel; Arroja, Luis; Ramos, Christian G.; Grilo, Andre; Sousa, Silvia A.; Leitao, Jorge H.

2011-01-01

The present work establishes intermittent operation of UASB reactors as a novel form of enhancing the anaerobic degradation of complex wastewaters and its conversion to usable biogas. Results show that the average methane production rate is 25% higher with the intermittent operation than with the continuous mode, meaning that it could produce 25% more electricity or heat. The methanization efficiency obtained in intermittent UASB reactors is around 20% higher than in the continuous systems, confirming a higher biological degradation of the substrates. It has been suggested that intermittent operation causes a forced adaptation of the biomass towards the degradation of complex substrates and results from morphological analyses of the biomass developed in intermittent and continuous UASB reactors showed marked differences between them. In order to gain a deeper knowledge on how microbial populations are affected by these operational parameters, a strategy involving the amplification, cloning, and analysis of the nucleotide sequences of genes encoding the 16S ribosomal RNA was undertaken and is described in this work. This strategy allowed the identification of a total of 49 different sequences. Results from the molecular characterization of the microbial populations are consistent with the higher methanization efficiency of the intermittent mode of operation.

Intermittency inhibited by transport: An exactly solvable model

Science.gov (United States)

Zanette, Damián H.

1994-04-01

Transport is incorporated in a discrete-time stochastic model of a system undergoing autocatalytic reactions of the type A-->2A and A-->0, whose population field is known to exhibit spatiotemporal intermittency. The temporal evolution is exactly solved, and it is shown that if the transport process is strong enough, intermittency is inhibited. This inhibition is nonuniform, in the sense that, as transport is strengthened, low-order population moments are affected before the high-order ones. Numerical simulations are presented to support the analytical results.

A Randomized Trial Comparing Part-time Patching with Observation for Intermittent Exotropia in Children 12 to 35 Months of Age.

Science.gov (United States)

Mohney, Brian G; Cotter, Susan A; Chandler, Danielle L; Holmes, Jonathan M; Chen, Angela M; Melia, Michele; Donahue, Sean P; Wallace, David K; Kraker, Raymond T; Christian, Melanie L; Suh, Donny W

2015-08-01

To determine the effectiveness of part-time patching for treating intermittent exotropia (IXT) in young children. Multicenter, randomized clinical trial. Two hundred one children 12 to 35 months of age with untreated IXT meeting the following criteria: (1) IXT at distance OR constant exotropia at distance and either IXT or exophoria at near, and (2) 15-prism diopter (Δ) or more exodeviation at distance or near by prism and alternate cover test (PACT) but at least 10 Δ exodeviation at distance by PACT. Participants were assigned randomly to either observation (no treatment for 6 months) or patching prescribed for 3 hours daily for 5 months, followed by 1 month of no patching. The primary outcome was deterioration, defined as constant exotropia measuring at least 10 Δ at distance and near or receipt of nonprotocol treatment for IXT. Of the 177 participants (88%) completing the 6-month primary outcome examination, deterioration occurred in 4.6% (4 of 87) of the participants in the observation group and in 2.2% (2 of 90) of the participants in the patching group (difference, 2.4%; P = 0.27; 95% confidence interval, -3.8% to +9.4%). Motor deterioration occurred in 2.3% (2 of 87) of the observation group and in 2.2% (2 of 90) of the patching group (difference, 0.08%; P = 0.55; 95% confidence interval, -5.8% to +6.1%). For the observation and patching groups, respectively, 6-month mean PACT measurements were 27.9 Δ versus 24.9 Δ at distance (P = 0.02) and 19.3 Δ versus 17.0 Δ at near (P = 0.10); 6-month mean exotropia control scores were 2.8 versus 2.3 points at distance (P = 0.02) and 1.4 versus 1.1 points at near (P = 0.26). Among children 12 to 35 months of age with previously untreated IXT, deterioration over 6 months was uncommon, with or without patching treatment. There was insufficient evidence to recommend part-time patching for the treatment of IXT in children in this age group. Copyright © 2015 American Academy of Ophthalmology. Published by Elsevier

Effect of Intermittent Energy Restriction on Flow Mediated Dilatation, a Measure of Endothelial Function: A Short Report

Directory of Open Access Journals (Sweden)

Michelle L. Headland

2018-06-01

Full Text Available Intermittent energy restriction is a popular alternative to daily energy restriction for weight loss; however, it is unknown if endothelial function, a risk factor for cardiovascular disease, is altered by periods of severe energy restriction. The objective of the study was to determine the impact of two consecutive very low energy intake days, which is the core component of the 5:2 intermittent energy restriction diet strategy, on endothelial function compared to consecutive ad libitum eating days. The secondary objective was to explore the effects of these dietary conditions on fasting glucose concentrations. This was a 4-week randomized, single-blinded, crossover study of 35 participants. Participants consumed a very low energy diet (500 calories for women, 600 calories for men on two consecutive days per week and 5 days of habitual eating. In weeks 3 and 4 of the trial, participants had measurements of flow mediated dilatation (FMD and blood samples taken following either 2 habitual eating days or 2 energy restricted days in a randomized order. FMD values were not different after the two eating states (8.6% vs. 8.3%, p = 0.7. All other outcome variables were unchanged. Endothelial function, as measured by flow mediated dilatation, was not altered by two consecutive very low energy intake days. Further investigations assessing the impact in specific population groups as well as different testing conditions would be beneficial.

Intermittent Hypoxic Episodes in Preterm Infants: Do They Matter?

OpenAIRE

Martin, Richard J.; Wang, Katherine; Köroğlu, Özge; Di Fiore, Juliann; Kc, Prabha

2011-01-01

Intermittent hypoxic episodes are typically a consequence of immature respiratory control and remain a troublesome challenge for the neonatologist. Furthermore, their frequency and magnitude are underestimated by clinically employed pulse oximeter settings. In extremely low birth weight infants the incidence of intermittent hypoxia progressively increases over the first 4 weeks of postnatal life, with a subsequent plateau followed by a slow decline beginning at weeks 6–8. Such episodic hypoxi...

Mobility and cloud: operating in intermittent, austere network conditions

OpenAIRE

Wee, Toon Joo; Ling, Yu Xian Eldine

2014-01-01

Approved for public release; distribution is unlimited Cloud computing is emerging as the mainstream platform for a range of on-demand applications, services, and infrastructure. Before the benefits of cloud computing are realized, several technology challenges must be addressed. Operating in intermittent and austere network conditions is one of such challenges, which navy ships face when communicating with land-based cloud computing environments. Given limited bandwidth and intermittent c...

The Effects of Intermittent Drinking Water Supply in Arraiján, Panama

OpenAIRE

Erickson, John Joseph

2016-01-01

Over three hundred million people throughout the world receive supply from piped drinking water distribution networks that operate intermittently. This dissertation evaluates the effects of intermittent supply on water quality, pipe damage and service reliability in four study zones (one continuous and three intermittent) in a peri-urban drinking water distribution network in Arraiján, Panama. Normal water quality in all zones was good, with 97% of routine water quality grab samples from the ...

Fuzzy Random λ-Mean SAD Portfolio Selection Problem: An Ant Colony Optimization Approach

Science.gov (United States)

Thakur, Gour Sundar Mitra; Bhattacharyya, Rupak; Mitra, Swapan Kumar

2010-10-01

To reach the investment goal, one has to select a combination of securities among different portfolios containing large number of securities. Only the past records of each security do not guarantee the future return. As there are many uncertain factors which directly or indirectly influence the stock market and there are also some newer stock markets which do not have enough historical data, experts' expectation and experience must be combined with the past records to generate an effective portfolio selection model. In this paper the return of security is assumed to be Fuzzy Random Variable Set (FRVS), where returns are set of random numbers which are in turn fuzzy numbers. A new λ-Mean Semi Absolute Deviation (λ-MSAD) portfolio selection model is developed. The subjective opinions of the investors to the rate of returns of each security are taken into consideration by introducing a pessimistic-optimistic parameter vector λ. λ-Mean Semi Absolute Deviation (λ-MSAD) model is preferred as it follows absolute deviation of the rate of returns of a portfolio instead of the variance as the measure of the risk. As this model can be reduced to Linear Programming Problem (LPP) it can be solved much faster than quadratic programming problems. Ant Colony Optimization (ACO) is used for solving the portfolio selection problem. ACO is a paradigm for designing meta-heuristic algorithms for combinatorial optimization problem. Data from BSE is used for illustration.

Improvement of thoracic aortic vasoreactivity by continuous and intermittent exercise in high-fat diet-induced obese rats.

Science.gov (United States)

Liu, Hongpeng; Yang, Zhen; Hu, Jian; Luo, Yan; Zhu, Lingqin; Yang, Huifang; Li, Guanghua

2015-07-01

The aim of the present study was to explore the effects of continuous and intermittent exercise on the thoracic aortic vasoreactivity and free radical metabolism in rats fed with a high-fat diet (HD). Sprague-Dawley (SD) rats were randomly divided into four groups (n=8, each group): Conventional diet (CD), HD, HD with continuous exercise (HCE) and HD with intermittent exercise (HIE). HCE rats swam once/day for 90 min; HIE rats performed swimming exercises 3 times/day, 30 min each time with an interval of 4 h. In these two groups, the exercise was conducted 5 days a week for 8 weeks. Rats in the CD and HD groups were fed without swimming training. At the end of the exercise, all the rats were sacrificed and the blood, thoracic aorta and myocardium were collected immediately. The thoracic aortic vasoreactivity, the plasma total cholesterol (TC), triglyceride (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), superoxide dismutase (SOD), malondialdehyde (MDA) and vascular endothelial nitric oxide synthase (eNOS) gene expression were measured. Compared to the control group, in the HD group the enhanced contractile response of the thoracic aortic rings to noradrenaline (NA) was observed (Pimprove the activity of the thoracic aorta in obese rats, which may be associated with enhanced antioxidant enzyme activity and reduced free radical generating. Additionally, intermittent exercise is better than the continuous exercise in improving the thoracic aorta vasoreactivity.

Efficacy and Safety of Azithromycin-Chloroquine versus Sulfadoxine-Pyrimethamine for Intermittent Preventive Treatment of Plasmodium falciparum Malaria Infection in Pregnant Women in Africa: An Open-Label, Randomized Trial.

Directory of Open Access Journals (Sweden)

Joshua Kimani

Full Text Available The World Health Organization recommends intermittent preventive treatment in pregnancy (IPTp with sulfadoxine-pyrimethamine (SP in African regions with moderate to high malaria transmission. However, growing resistance to SP threatens the effectiveness of IPTp-SP, and alternative drugs are needed. This study tested the efficacy, tolerability, and safety of a fixed-dose combination azithromycin-chloroquine (AZCQ; 250 mg AZ/155 mg CQ base for IPTp relative to IPTp-SP.A randomized, Phase 3, open-label, multi-center study was conducted in sub-Saharan Africa (Benin, Kenya, Malawi, Tanzania, and Uganda between October 2010 and November 2013. Pregnant women received 3 IPTp courses with AZCQ (each course: 1,000/620 mg AZCQ QD for 3 days or SP (each course 1,500/75 mg SP QD for 1 day at 4- to 8-week intervals during the second and third trimester. Long-lasting insecticide-treated bednets were also provided at enrollment. Study participants were followed up until day 28 post delivery (time window: day 28-42. The primary endpoint was the proportion of participants with sub-optimal pregnancy outcomes (a composite endpoint comprising live-borne neonates with low birth weight [LBW, 28 weeks], abortion [≤28 weeks], lost to follow-up prior to observation of pregnancy outcome, or missing birth weight. The study was terminated early after recruitment of 2,891 of the planned 5,044 participants, due to futility observed in a pre-specified 35% interim analysis. In the final intent-to-treat dataset, 378/1,445 (26.2% participants in the AZCQ and 342/1,445 (23.7% in the SP group had sub-optimal pregnancy outcomes, with an estimated risk ratio (RR of 1.11 (95% CI: 0.97, 1.25; p = 0.12. There was no significant difference in the incidence of LBW between treatment groups (57/1138 [5.0%] in the AZCQ group, 68/1188 [5.7%] in the SP group, RR 0.87 [95% CI: 0.62, 1.23]; p = 0.44. IPTp-AZCQ was less well-tolerated in mothers than IPTp-SP. Occurrences of congenital anomalies

Wave-number spectra and intermittency in the terrestrial foreshock region.

Science.gov (United States)

Narita, Y; Glassmeier, K-H; Treumann, R A

2006-11-10

Wave-number spectra of magnetic field fluctuations are directly determined in the terrestrial foreshock region (upstream of a quasiparallel collisionless shock wave) using four-point Cluster spacecraft measurements. The spectral curve is characterized by three ranges reminiscent of turbulence: energy injection, inertial, and dissipation range. The spectral index for the inertial range spectrum is close to Kolmogorov's slope, -5/3. On the other hand, the fluctuations are highly anisotropic and intermittent perpendicular to the mean magnetic field direction. These results suggest that the foreshock is in a weakly turbulent and intermittent state in which parallel propagating Alfvén waves interact with one another, resulting in the phase coherence or the intermittency.

Sodium bicarbonate ingestion improves Yo-Yo intermittent recovery test 1 performance: a randomized crossover trial

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Dixon H

2017-04-01

Full Text Available Helen Dixon,1 Catherine E Baker,2 Julien S Baker,3 Susan Dewhurst,4 Lawrence D Hayes4 1School of Human Sciences, London Metropolitan University, London, 2English Institute of Sport, Bisham Abbey National Sports Center, Buckinghamshire, 3Institute of Clinical Exercise and Health Science, University of the West of Scotland, Hamilton, 4Department of Medical and Sport Sciences, University of Cumbria, Lancaster, UK Abstract: This study investigated the effect of sodium bicarbonate (NaHCO3– ingestion on the Yo-Yo intermittent recovery test 1 (IR1. We tested the hypothesis that acute ingestion of NaHCO3– would increase blood lactate concentrations [BLa], enhance performance, and reduce rating of perceived exertion (RPE in the Yo-Yo IR1. Eight recreationally active males (N=8, age: 26±4 yr, height: 178±6 cm, body mass: 82±10 kg participated in the Yo-Yo IR1 on two separate occasions, separated by 1 wk, in a randomized crossover design. Following familiarization, during seated rest, participants’ pretest [BLa] was taken, and participants then consumed either a placebo of 0.3 g·kg–1 body weight sodium chloride or 0.3 g·kg–1 body weight NaHCO3–. Sixty minutes postingestion, a standardized warm-up preceded the Yo-Yo IR1. Upon completion, postexercise [BLa] (mmol·L–1, RPE (arbitrary units and Yo-Yo IR1 time to fatigue (s were recorded. Paired t-test revealed a small but significant improvement in Yo-Yo IR1 performance under the NaHCO3– condition (610±267 sec, compared to the placebo condition (556±259 sec; p=0.01; Cohen’s d=0.20. [BLa] increased more under the NaHCO3– condition (1.6±0.7 to 17.5±5.2 mmol·L–1; p<0.001; Cohen’s d=4.29, compared to the placebo condition (2.0±0.7 to 11.5±5.0 mmol·L–1; p=0.001; Cohen’s d=2.66. Postexercise RPE was not significantly different between conditions. The results of this study suggest that acute NaHCO3– ingestion improves Yo-Yo IR1 performance without altering RPE, likely

Optimal Control of a Surge-Mode WEC in Random Waves

Energy Technology Data Exchange (ETDEWEB)

Chertok, Allan [Resolute Marine Energy, Inc., Boston, MA (United States); Ceberio, Olivier [Resolute Marine Energy, Inc., Boston, MA (United States); Staby, Bill [Resolute Marine Energy, Inc., Boston, MA (United States); Previsic, Mirko [Re Vision Consulting, Sacramento, CA (United States); Scruggs, Jeffrey [Univ. of Michigan, Ann Arbor, MI (United States); Van de Ven, James [Univ. of Minnesota, Minneapolis, MN (United States)

2016-08-30

The objective of this project was to develop one or more real-time feedback and feed-forward (MPC) control algorithms for an Oscillating Surge Wave Converter (OSWC) developed by RME called SurgeWEC™ that leverages recent innovations in wave energy converter (WEC) control theory to maximize power production in random wave environments. The control algorithms synthesized innovations in dynamic programming and nonlinear wave dynamics using anticipatory wave sensors and localized sensor measurements; e.g. position and velocity of the WEC Power Take Off (PTO), with predictive wave forecasting data. The result was an advanced control system that uses feedback or feed-forward data from an array of sensor channels comprised of both localized and deployed sensors fused into a single decision process that optimally compensates for uncertainties in the system dynamics, wave forecasts, and sensor measurement errors.

ANESTHETIC MANAGEMENT FOR A PATIENT WITH ACUTE INTERMITTENT PORPHYRIA

Directory of Open Access Journals (Sweden)

Nenad Savić

2010-09-01

Full Text Available Acute intermittent porphyria is a rare metabolic disorder resulting from a partial deficiency of porphobilinogen deaminase, enzyme in the heme biosynthetic pathway. Its inheritance is autosomal dominant. A deficiency of porphobilinogen deaminase is not sufficient by its self to produce acute intermittent porphyria, and other activating factors must also be present. These include some drugs, hormones, infection, injury and alcohol. Besides others, anesthetics have been implicated in the triggering of a number of severe porphyric reactions. Although there is no clinical evidence, the fear of hypothesized porphyrinogenicity of repetitive anesthetics exposures still remains. Despite these doubts, we report here the case of uneventful repeated exposure to anesthetics in a patient suffering from acute intermittent porphyria, within a fifteen- month period. On both occasions, the patient was safely exposed to certain anesthetics included: propofol, sevoflurane, rocuronium, midazolam and fentanyl.

Sustainable integration of high levels of intermittent generation

International Nuclear Information System (INIS)

Pereira, R.; Cabral, P.

2005-01-01

The sustainable development of electric power systems rely on three main drivers: the security of supply, the competitiveness and the protection of the environment. For this purpose the promotion of endogenous energy sources, mainly the renewable ones, should be underlined. Still, most of renewable energy sources raise very sensitive issues concerning the security of supply, due to its randomness and unpredictability. The wind power, currently in its fast growing development, plays a relevant role on this matter. From the demand-side perspective, there is also a lot to do regarding the promotion of more efficient use of energy as well as mechanisms that contribute to security of supply. This paper aims to present guidelines for the selection of the most adequate solutions regarding: sustainable evolution of renewable generation technologies, based on the most meritorious resources under economic and security of supply assessments; complementary energy storage systems that allow the integration of intermittent generation ensuring adequate security of supply levels; and sustainable evolution of demand, based on DSM measures selected from different available alternatives. (author)

Intermittent fasting, energy balance and associated health outcomes in adults: study protocol for a randomised controlled trial.

Science.gov (United States)

Templeman, Iain; Thompson, Dylan; Gonzalez, Javier; Walhin, Jean-Philippe; Reeves, Sue; Rogers, Peter J; Brunstrom, Jeffrey M; Karagounis, Leonidas G; Tsintzas, Kostas; Betts, James A

2018-02-02

Prior studies have shown that intermittent fasting is capable of producing improvements in body weight and fasted health markers. However, the extent to which intermittent fasting incurs compensatory changes in the components of energy balance and its impact on postprandial metabolism are yet to be ascertained. A total of 30-36 lean participants and 30-36 overweight/obese participants will be recruited to provide two separate study groups who will undergo the same protocol. Following an initial assessment of basic anthropometry and key health markers, measurements of habitual energy intake (weighed food and fluid intake) and physical activity energy expenditure (combined heart rate and accelerometry) will be obtained over 4 weeks under conditions of energy balance. Participants will then be randomly allocated to one of three experimental conditions for 20 days, namely (1) daily calorie restriction (reduce habitual daily energy intake by 25%), (2) intermittent fasting with calorie restriction (alternate between 24-hour periods of fasting and feeding to 150% of habitual daily energy intake), (3) intermittent fasting without calorie restriction (alternate between 24-hour periods of fasting and feeding to 200% of habitual daily energy intake). In addition to continued monitoring of energy intake and physical activity during the intervention, participants will report for laboratory-based assessments of various metabolic parameters both before and after the intervention. Specifically, fasting and postprandial measurements of resting metabolic rate, substrate oxidation, appetite, food preference, and plasma concentrations of key metabolites and hormones will be made, in addition to subcutaneous abdominal adipose tissue biopsies in the fasted state and an assessment of body composition via dual-energy x-ray absorptiometry. Comparing observed changes in these measures across the three intervention arms in each group will establish the impact of intermittent fasting on

Backward Stochastic Riccati Equations and Infinite Horizon L-Q Optimal Control with Infinite Dimensional State Space and Random Coefficients

International Nuclear Information System (INIS)

Guatteri, Giuseppina; Tessitore, Gianmario

2008-01-01

We study the Riccati equation arising in a class of quadratic optimal control problems with infinite dimensional stochastic differential state equation and infinite horizon cost functional. We allow the coefficients, both in the state equation and in the cost, to be random.In such a context backward stochastic Riccati equations are backward stochastic differential equations in the whole positive real axis that involve quadratic non-linearities and take values in a non-Hilbertian space. We prove existence of a minimal non-negative solution and, under additional assumptions, its uniqueness. We show that such a solution allows to perform the synthesis of the optimal control and investigate its attractivity properties. Finally the case where the coefficients are stationary is addressed and an example concerning a controlled wave equation in random media is proposed

On the degrees-of-freedom of the MIMO three-way channel with intermittent connectivity

KAUST Repository

Chaaban, Anas

2017-08-29

The degrees-of-freedom (DoF) of the multi-antenna three-way channel (3WC) with an intermittent node is studied. Special attention is given to the impact of adaptation when the intermittent node has the largest number of antennas. A non-adaptive transmission scheme based on interference alignment, zero-forcing, and erasure-channel treatment is proposed, and its corresponding DoF region is derived. Then, it is shown that this scheme achieves the sum-DoF of the intermittent channel, in addition to the DoF region of the nonintermittent one. Thus, adaptation is not necessary from those perspectives. To the contrary, it is shown that adaptation is necessary for achieving the DoF region of the intermittent case. This is shown by deriving an outer bound for the intermittent channel with nonadaptive encoding, and proposing an adaptive scheme which achieves DoF tuples outside this bound. This highlights the importance of cooperation in this intermittent network.

Characterization of wind power resource and its intermittency

Science.gov (United States)

Gunturu, U. B.; Schlosser, C. A.

2011-12-01

Wind resource in the continental and offshore United States has been calculated and characterized using metrics that describe - apart from abundance - its availability, persistence and intermittency. The Modern Era Retrospective-Analysis for Research and Applications (MERRA) boundary layer flux data has been used to construct wind power density profiles at 50, 80, 100 and 120 m turbine hub heights. The wind power density estimates at 50 m are qualitatively similar to those in the US wind atlas developed by the National Renewable Energy Laboratory (NREL), but quantitatively a class less in some regions, but are within the limits of uncertainty. We also show that for long tailed distributions like those of the wind power density, the mean is an overestimation and median is a more robust metric for summary representation of wind power resource.Generally speaking, the largest and most available wind power density resources are found in off-shore regions of the Atlantic and Pacific coastline, and the largest on-shore resource potential lies in the central United States. However, the intermittency and widespread synchronicity of on-shore wind power density are substantial, and highlights areas where considerable back-up generation technologies will be required. Generation-duration curves are also presented for the independent systems operator (ISO) zones of the U.S. to highlight the regions with the largest capacity factor (MISO, ERCOT, and SWPP) as well as the periods and extent to which all ISOs contain no wind power and the potential benefits of aggregation on wind power intermittency in each region. The impact of raising the wind turbine hub height on metrics of abundance, persistence, variability and intermittency is analyzed. There is a general increase in availability and abundance of wind resource but there is also an increase in intermittency with respect to a 'usable wind power' crossing level in low resource regions. A similar perspective of wind resource for

Study the Effect of Intermittent and Continuous Ponding Depths by Using Different Heads to Leach Water

Directory of Open Access Journals (Sweden)

Nesrin J. AL-Mansori

2018-03-01

Full Text Available As results of using water for irrigated lands in a random manner in a time of shortage main water resources, Experimental work carried out to study the effect of continuous and intermittent ponding depth on the leaching processes. Sandy soil used, sourced from Hilla / Al-Jameeya, at Hilla city. Sieve analysis and hydrometer testing used to identify the properties of the soil. A model used with dimensions of 30, 30 and, 70 cm, with two different heads of water. Shatt-Al-Hilla River samples used in the leaching process.   Chemical tests carried out before the leaching process to identify changes in the proprieties in both water and soil. Leachate collected from two soil columns drained into boxes and tests carried out every 30 minutes. After the leaching process was complete, the soil was re-tested. Chemical tests on soil samples and the collected water applied after leaching for 47.5 cm and 52.5cm heads. From the results،, it can be notice that electrical conductivity for the outlet discharge from soil samples decreased faster with time, then slowing down until the end of leaching process.  The same pattern can be seen for all soil properties. In continuous leaching, a large quantity of water is required over a short leaching period, the inverse true for intermittent leaching. All parameters reduce with time in continuous leaching in comparison to intermittent leaching but when the water level in the soil column compared, it can inferred that increasing the head will reduce all the parameters for soil.

Intermittent hypoxia in childhood: the harmful consequences versus potential benefits of therapeutic uses

Directory of Open Access Journals (Sweden)

Tatiana V. Serebrovskaya

2015-05-01

Full Text Available Intermittent hypoxia often occurs in early infancy in both preterm and term infants and especially at 36 to 44 weeks postmenstrual age. These episodes of intermittent hypoxia could result from sleep-disordered breathing or may be temporally unrelated to apnea or bradycardia events. There are numerous reports indicating adverse effects of intermittent hypoxia on development, behavior, academic achievement and cognition in children with sleep apnea syndrome. It remains uncertain the exact causative relationship between the neurocognitive and behavioral morbidities and intermittent hypoxia and/or its associated sleep fragmentation. On the other hand, well-controlled and moderate intermittent hypoxia conditioning/training has been used in sick children for treating their various forms of bronchial asthma, allergic dermatoses, autoimmune thyroiditis, cerebral palsy, and obesity. This review article provides an updated and impartial analysis on the currently available evidence in supporting either side of the seemingly contradictory scenarios. We wish to stimulate a comprehensive understanding of such a complex physiological phenomenon as intermittent hypoxia, which may be accompanied by other confounding factors (e.g. hypercapnia, polycythemia, in order to prevent or reduce its harmful consequences, while maximize its potential utility as an effective therapeutic tool in pediatric patients.

Intermittent Domestic Water Supply: A Critical Review and Analysis of Causal-Consequential Pathways

Directory of Open Access Journals (Sweden)

S. E. Galaitsi

2016-06-01

Full Text Available Communities in many parts of the world, especially in developing countries, face obstacles in supplying continuous water to household consumers. Authorities often cite water scarcity as the cause, but we demonstrate that environmental constraints constitute only one aspect of a multi-dimensional problem. By asking what causes intermittent domestic water supply, this literature review (129 articles identifies 47 conditions of intermittent systems and the causal-consequential pathways between them that can reinforce intermittency. These pathways span several disciplines including engineering, government administration and anthropology, and when viewed together they (1 emphasize the human drivers of intermittency; (2 suggest generalized interventions; and (3 reveal a gap in the literature in terms of meaningful categorizations of the reliability of intermittent supplies. Based on the reliability of consumers’ water access, we propose three categories of intermittency—predictable, irregular, and unreliable—to facilitate comparisons between case studies and transfers of solutions.

Intermittent Aeration Suppresses Nitrite-Oxidizing Bacteria in Membrane-Aerated Biofilms: A Model-Based Explanation

DEFF Research Database (Denmark)

Ma, Yunjie; Domingo Felez, Carlos; Plósz, Benedek G.

2017-01-01

. On the basis of dissolved oxygen (DO), ammonium, nitrite, and nitrate profiles within the biofilm and in the bulk, a 1-dimensional nitrifying biofilm model was developed and calibrated. The model was utilized to explore the potential mechanisms of NOB suppression associated with intermittent aeration...... nitritation, strategies to suppress nitrite-oxidizing bacteria (NOB) are needed, which are ideally grounded on an understanding of underlying mechanisms. In this study, a nitrifying MABR was operated under intermittent aeration. During eight months of operation, AOB dominated, while NOB were suppressed...... during intermittent aeration was mostly explained by periodic inhibition caused by free ammonia due to periodic transient pH upshifts. Dissolved oxygen limitation did not govern NOB suppression. Different intermittent aeration strategies were then evaluated for nitritation success in intermittently...

Optimal Allocation of Renewable Energy Sources for Energy Loss Minimization

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Vaiju Kalkhambkar

2017-03-01

Full Text Available Optimal allocation of renewable distributed generation (RDG, i.e., solar and the wind in a distribution system becomes challenging due to intermittent generation and uncertainty of loads. This paper proposes an optimal allocation methodology for single and hybrid RDGs for energy loss minimization. The deterministic generation-load model integrated with optimal power flow provides optimal solutions for single and hybrid RDG. Considering the complexity of the proposed nonlinear, constrained optimization problem, it is solved by a robust and high performance meta-heuristic, Symbiotic Organisms Search (SOS algorithm. Results obtained from SOS algorithm offer optimal solutions than Genetic Algorithm (GA, Particle Swarm Optimization (PSO and Firefly Algorithm (FFA. Economic analysis is carried out to quantify the economic benefits of energy loss minimization over the life span of RDGs.

Intermittent turbulence and oscillations in the stable boundary layer over land

NARCIS (Netherlands)

Wiel, van de B.

2002-01-01

As the title of this thesis indicates, our main subject of interest is: "Intermittent turbulence and oscillation in the stable boundary layer over land". As such, this theme connects the different chapters. Here, intermittent turbulence is defined as a sequence of events were 'burst' of

Effect of chronic intermittent hypoxia on glycometabolism in rat’ liver and the mechanism thereof

Directory of Open Access Journals (Sweden)

Wei YU

2018-03-01

Full Text Available Objective To investigate the effects of chronic intermittent hypoxia on the adipose factor and the expressions of insulin receptor substrate 2 (IRS-2, glucose transporter 2 (GLUT-2 and leptin in rat liver. Methods Twenty-four mature SD rats were randomly divided into 3 groups: control group (UC, chronic intermittent hypoxia group (CIH and reoxygenation group (RH. The arterial blood gas analysis was performed after the establishment of rat model. The serum fasting blood glucose (FBG and fasting insulin (FINS in each group were detected by peroxidase method; the concentrations of free fatty acids (FFA and leptin were detected by ELISA. The expressions of mRNA and protein of GLUT-2, IRS-2 and leptin were detected by qRT-PCR and Western blotting. Results The serous concentrations of FBG, FINS, FFA and leptin were significantly higher in CIH group than in UC group (P<0.05, and were dramatically higher in RH group than in both CIH group (P=0.003 and UC group (P=0.000. Western blotting and qRT-PCR detection showed that the protein and mRNA expressions of GLUT-2 and IRS-2 were significantly lower in CIH group than in RH group of rat liver (P<0.05, while were markedly lower in RH group than in UC group (P<0.05; the expressions of leptin protein and mRNA were significantly higher in CIH group than in RH group (P<0.05, while were obviously higher in RH group than in UC group of rat liver (P<0.05. Conclusion Insulin resistance induced by chronic intermittent hypoxia may be associated with the elevation of serum FFA and leptin, and be related to the decreased expression of GLUT-2 and IRS-2 and increased expression of leptin in liver. DOI: 10.11855/j.issn.0577-7402.2018.03.05

Nitrates for stable angina: a systematic review and meta-analysis of randomized clinical trials.

Science.gov (United States)

Wei, Jiafu; Wu, Taixiang; Yang, Qing; Chen, Mao; Ni, Juan; Huang, Dejia

2011-01-07

To assess the effect (harms and benefits) of nitrates for stable angina. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE. Randomized controlled trials with both parallel and crossover design were included. The following outcome measures were evaluated: number of angina attacks weekly and nitroglycerin consumption, quality of life, total exercise duration, time to onset of angina and time to 1 mm ST depression. Fifty-one trials with 3595 patients meeting inclusion criteria were analyzed. Both intermittent and continuous regimens of nitrates lengthened exercise duration significantly by 31 and 53 s respectively. The number of angina attacks was significantly reduced by 2.89 episodes weekly for continuous administration and 1.5 episodes weekly for intermittent administration. With intermittent administration, increased dose provided with 21 s more length of exercise duration. With continuous administration, exercise duration was pronged more in low-dose group. Quality of life was not improved by continuous application of GTN patches and was similar between continuous and intermittent groups. In addition, 51.6% patients receiving nitrates complained with headache. Long-term administration of nitrates was beneficial for angina prophylaxis and improved exercise performance but might be ineffective for improving quality of life. With continuous regimen, low-dose nitrates were more effective than high-dose ones for improving exercise performance. By contrast, with intermittent regimen, high-dose nitrates were more effective. In addition, intermittent administration could bring zero-hour effect. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Randomized controlled trial of enoxaparin versus intermittent pneumatic compression for venous thromboembolism prevention in Japanese surgical patients with gynecologic malignancy.

Science.gov (United States)

Nagata, Chie; Tanabe, Hiroshi; Takakura, Satoshi; Narui, Chikage; Saito, Motoaki; Yanaihara, Nozomu; Okamoto, Aikou

2015-09-01

The aim of this study was to compare the efficacy and safety of enoxaparin and intermittent pneumatic compression (IPC) for venous thromboembolism (VTE) prevention in Japanese surgical patients with gynecologic malignancy. Patients ≥ 40 years old undergoing major surgery for gynecologic malignancy without preoperative VTE were included. Written informed consent was obtained. Enrolled patients received IPC immediately before surgery. After surgery, they were randomly assigned to either an enoxaparin group or an IPC-alone group. The enoxaparin group received enoxaparin injection (20 mg, subcutaneous, every 12 h) from postoperative day 2 to 8. IPC was discontinued after the first injection. In the IPC-alone group, IPC was continued until full ambulation. The primary end-point was incidence of VTE, including pulmonary embolism and deep vein thrombosis, regardless of symptoms. An interim analysis was to be conducted when the first 30 patients had completed the study protocol. A Data and Safety Monitoring Board was established for making recommendation on the continuation or termination of the study based on the interim results. At the time of the interim analysis, six cases of VTE were found: five in the IPC-alone group and one in the enoxaparin group (Fisher's exact test, P = 0.08). Three patients in the IPC-alone group developed pulmonary embolism, but none in the enoxaparin group did so (Fisher's exact test, P = 0.10). The study was terminated following the Data and Safety Monitoring Board's recommendation. Enoxaparin might have lowered the risk of VTE among surgical patients with gynecologic malignancy. Further studies are necessary to confirm this. © 2015 Japan Society of Obstetrics and Gynecology.

Obstructive sleep apnea and intermittent hypoxia increase expression of dual specificity phosphatase 1.

Science.gov (United States)

Hoffmann, Michal S; Singh, Prachi; Wolk, Robert; Narkiewicz, Krzysztof; Somers, Virend K

2013-12-01

Dual specificity phosphatase 1 (DUSP1) inhibits mitogen activated protein kinase activity, and is activated by several stimuli such as sustained hypoxia, oxidative stress, and hormones. However, the effect of intermittent hypoxia is not known. The aim of this study was to evaluate the role of intermittent hypoxia on DUSP1 expression, and to validate its role in a human model of intermittent hypoxia, as seen in obstructive sleep apnea (OSA). OSA is characterized by recurrent episodes of hypoxemia/reoxygenation and is a known risk factor for cardiovascular morbidity. In-vitro studies using human coronary artery endothelial cells (HCAEC) and ex-vivo studies using white blood cells isolated from healthy and OSA subjects. Intermittent hypoxia induced DUSP1 expression in human coronary artery endothelial cells (HCAEC), and in granulocytes isolated from healthy human subjects. Functionally, DUSP1 increased the expression and activity of manganese superoxide dismutase (MnSOD) in HCAEC. Further, significant increases in DUSP1 mRNA from total blood, and in DUSP1 protein in mononuclear cells and granulocytes isolated from OSA subjects, were observed in the early morning hours after one night of intermittent hypoxemia due to untreated OSA. This early-morning OSA-induced augmentation of DUSP1 gene expression was attenuated by continuous positive airway pressure (CPAP) treatment of OSA. Intermittent hypoxia increases MnSOD activity via increased DUSP1 expression in HCAEC. Similarly, overnight intermittent hypoxemia in patients with OSA induces expression of DUSP1, which may mediate increases of MnSOD expression and activity. This may contribute significantly to neutralizing the effects of reactive oxygen species, a consequence of the intermittent hypoxemia/reperfusion elicited by OSA. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Intermittent oral iron supplementation during pregnancy (Review)

Science.gov (United States)

Peña-Rosas, Juan Pablo; De-Regil, Luz Maria; Dowswell, Therese; Viteri, Fernando E

2014-01-01

Background Anaemia is a frequent condition during pregnancy, particularly among women from developing countries who have insufficient iron intake to meet increased iron needs of both the mother and the fetus. Traditionally, gestational anaemia has been prevented with the provision of daily iron supplements throughout pregnancy, but adherence to this regimen due to side effects, interrupted supply of the supplements, and concerns about safety among women with an adequate iron intake, have limited the use of this intervention. Intermittent (i.e. one, two or three times a week on non-consecutive days) supplementation with iron alone or in combination with folic acid or other vitamins and minerals has recently been proposed as an alternative to daily supplementation. Objectives To assess the benefits and harms of intermittent supplementation with iron alone or in combination with folic acid or other vitamins and minerals to pregnant women on neonatal and pregnancy outcomes. Search methods We searched the Cochrane Pregnancy and Childbirth Group’s Trials Register (23 March 2012). We also searched the WHO International Clinical Trials Registry Platform (ICTRP) for ongoing studies and contacted relevant organisations for the identification of ongoing and unpublished studies (23 March 2012). Selection criteria Randomised or quasi-randomised trials. Data collection and analysis We assessed the methodological quality of trials using standard Cochrane criteria. Two review authors independently assessed trial eligibility, extracted data and conducted checks for accuracy. Main results This review includes 21 trials from 13 different countries, but only 18 trials (with 4072 women) reported on our outcomes of interest and contributed data to the review. All of these studies compared daily versus intermittent iron supplementation. Three studies provided iron alone, 12 iron+folic acid and three more iron plus multiple vitamins and minerals. Their methodological quality was mixed

Intermittent chaotic chimeras for coupled rotators

DEFF Research Database (Denmark)

Olmi, Simona; Martens, Erik Andreas; Thutupalli, Shashi

2015-01-01

Two symmetrically coupled populations of N oscillators with inertia m display chaotic solutions with broken symmetry similar to experimental observations with mechanical pendulums. In particular, we report evidence of intermittent chaotic chimeras, where one population is synchronized and the other...

Cost effectiveness of intermittent screening followed by treatment versus intermittent preventive treatment during pregnancy in West Africa

DEFF Research Database (Denmark)

Fernandes, Silke; Sicuri, Elisa; Halimatou, Diawara

2016-01-01

$/DALY averted. Simulations show that cost-effectiveness of ISTp-AL increases as the efficacy of IPTp-SP decreases, though the specific threshold at which ISTp-AL becomes cost-effective depends on assumptions about the contribution of bed nets to malaria control, bed net coverage and the willingness......-to-pay threshold used.  Conclusions: At SP efficacy levels currently observed in the trial settings it would not be cost-effective to switch from IPTp-SP to ISTp-AL, mainly due to the substantially higher costs of ISTp-AL and limited difference in outcomes. The modelling results indicate thresholds below which IPT......Background: Emergence of high-grade sulfadoxine-pyrimethamine (SP) resistance in parts of Africa has led to growing concerns about the efficacy of intermittent preventive treatment of malaria during pregnancy (IPTp) with SP. The incremental cost-effectiveness of intermittent screening and treatment...

Muscular soreness following prolonged intermittent high-intensity shuttle running.

Science.gov (United States)

Thompson, D; Nicholas, C W; Williams, C

1999-05-01

The aim of this study was to examine the impact of prolonged intermittent high-intensity shuttle running on soreness and markers of muscle damage. Sixteen males took part in the study, half of whom were assigned to a running group and half to a resting control group. The exercise protocol involved 90 min of intermittent shuttle running and walking (Loughborough Intermittent Shuttle Test: LIST), reflecting the activity pattern found in multiple-sprint sports such as soccer. Immediately after exercise, there was a significant increase (P < 0.05) in serum activities of creatine kinase and aspartate aminotransferase, and values remained above baseline for 48 h (P < 0.05). Median peak activities of creatine kinase and aspartate aminotransferase occurred 24 h post-exercise and were 774 and 43 U x l(-1), respectively. The intensity of general muscle soreness, and in the specific muscles investigated, was greater than baseline for 72 h after the shuttle test (P < 0.05), peaking 24-48 h post-exercise (P < 0.05). Muscle soreness was not correlated with either creatine kinase or aspartate aminotransferase activity. Soreness was most frequently reported in the hamstrings. Neither soreness nor serum enzyme activity changed in the controls over the 4 day observation period. It appears that unaccustomed performance of prolonged intermittent shuttle running produces a significant increase in both soreness and markers of muscle damage.

Chronic intermittent hyperoxia alters the development of the hypoxic ventilatory response in neonatal rats.

Science.gov (United States)

Logan, Sarah; Tobin, Kristina E; Fallon, Sarah C; Deng, Kevin S; McDonough, Amy B; Bavis, Ryan W

2016-01-01

Chronic exposure to sustained hyperoxia alters the development of the respiratory control system, but the respiratory effects of chronic intermittent hyperoxia have rarely been investigated. We exposed newborn rats to short, repeated bouts of 30% O2 or 60% O2 (5 bouts h(-1)) for 4-15 days and then assessed their hypoxic ventilatory response (HVR; 10 min at 12% O2) by plethysmography. The HVR tended to be enhanced by intermittent hyperoxia at P4 (early phase of the HVR), but it was significantly reduced at P14-15 (primarily late phase of the HVR) compared to age-matched controls; the HVR recovered when individuals were returned to room air and re-studied as adults. To investigate the role of carotid body function in this plasticity, single-unit carotid chemoafferent activity was recorded in vitro. Intermittent hyperoxia tended to decrease spontaneous action potential frequency under normoxic conditions but, contrary to expectations, hypoxic responses were only reduced at P4 (not at P14) and only in rats exposed to higher O2 levels (i.e., intermittent 60% O2). Rats exposed to intermittent hyperoxia had smaller carotid bodies, and this morphological change may contribute to the blunted HVR. In contrast to rats exposed to intermittent hyperoxia beginning at birth, two weeks of intermittent 60% O2 had no effect on the HVR or carotid body size of rats exposed beginning at P28; therefore, intermittent hyperoxia-induced respiratory plasticity appears to be unique to development. Although both intermittent and sustained hyperoxia alter carotid body development and the HVR of rats, the specific effects and time course of this plasticity differs. Copyright © 2015 Elsevier B.V. All rights reserved.

Lifetime characterization via lognormal distribution of transformers in smart grids: Design optimization

International Nuclear Information System (INIS)

Chiodo, Elio; Lauria, Davide; Mottola, Fabio; Pisani, Cosimo

2016-01-01

Highlights: • A tool for choosing the transformer rating under highly-intermittent loads is proposed. • Analytical formulation for the aging of transformers in smart grid scenarios is presented. • Randomness of loading profiles are addressed in terms of stochastic processes. • The robustness of the Wiener process is validated for modeling load variability. - Abstract: In this paper, the problem of the optimal rating of transformers in smart grids is properly discussed with respect to the specific load characteristics. The design is based on the accurate prediction of the lifetime degradation of mineral-oil-immersed transformers subject to highly intermittent loads. In fact, by investigating the nature of the loads in the smart grid scenario, it clearly appears that the intermittent nature of the power demand increases drastically. In this context, specific tools for the characterization of the lifetime duration are required, since severe reduction of the transformer’s life can be observed due to overloads, even in the case of short-duration overloads. The classical approaches based on using the equivalent thermal current to predict the transformer’s lifetime might result in incorrect estimates, thus requiring advanced models that can deal with the time variability of the load. In this paper, the randomness of the load powers is addressed in terms of stochastic processes. In particular, the Wiener process is demonstrated to provide robust modeling of load variability. By starting from this assumption, it was demonstrated analytically that the hot-spot temperature, which is a major contributor to the degradation of the transformer’s lifetime, also is a stochastic process. Then, in spite of the nonlinearity of the thermal model, the hot-spot temperature can be represented as a Wiener process, the robustness of which has been verified adequately. By taking into account the nonlinear relationship between the hot-spot temperature and the lifetime, the

The problem of intermittency of renewable energies: solar and wind energy

International Nuclear Information System (INIS)

Livet, Frederic

2011-01-01

As solar and wind energies are to be intensively developed but are intermittent, more or less regular and unpredictable, the author first discusses methods which are presently used to manage this intermittency in various European countries. He also discusses the various methods which are proposed to compensate this intermittency: hydraulic storage, hydrogen-based storage, batteries, and large scale interconnections. He gives and comments cost assessments of the various proposed methods and of capacities. He shows that various measures which are discussed at the European level to promote renewable energies and to promote electricity exchanges will in fact result in a three times higher price of electricity for individuals

The effects of continuous and intermittent aerobic exercise on lipid profile and fasting blood sugar in women with a body mass index more than 25 kg/m2: a randomized controlled trial

Directory of Open Access Journals (Sweden)

Alizadeh Z

2011-07-01

Full Text Available "n 800x600 Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table 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:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif";} Background: Obesity is a major health problem all around the world. On the other hand, few people, especially women, are physically active to the levels recommended by Healthy People 2010 web site managed by the U.S. Department of Health and Human Services. The objective of this study was to compare the potential effects of intermittent and continuous exercise programs combined with concurrent calorie restriction diets on lipid profile and fasting blood sugar in overweight and obese females."n"nMethods : Forty-five women with a sedentary life style and a BMI greater than 25 kg/m2, were randomly assigned to one of the three groups (15 subjects in each group: a 40 minutes of medium-intensity intermittent exercise (64-76% of maximal heart rate, 3 bouts per day for 5 days a week, b a single bout of a 40-minute continuous exercise per day for 5 days a week, C the non-exercising control group. A self-monitored calorie restricted diet was recommended to all participants by a dietitian. The lipid profile, fasting blood sugar and blood pressure of all participants were assessed at baseline and 12 weeks after the intervention period."n"nResults : After the intervention, there were no significant differences among the groups in terms of lipid profile [cholesterol (P=0.94, triglyceride (P=0.62] fasting blood sugar (P=0.054, systolic blood pressure (P=0.84 or diastolic blood pressure (P=0.30."n"nConclusion: There seems to be no significant differences between short term continuous and intermittent aerobic

Demographics and frequency of the intermittently upturned omentum at CT

Energy Technology Data Exchange (ETDEWEB)

Penn, Alex; Wang, Wilbur; Wang, Zhen Jane; Yee, Judy; Webb, Emily M.; Yeh, Benjamin M., E-mail: ben.yeh@ucsf.edu

2013-11-01

Objectives: To describe the demographics and frequency of the intermittently upturned omentum at CT. Methods: We retrospectively reviewed abdominal CT scans of 336 consecutive patients (189 men and 147 women) who were imaged between June 1 and June 17, 2010 and who had prior comparison scans. Readers recorded the presence or absence of an intermittently upturned omentum, defined as a thick rind of fat interposed between the liver and the anterior abdominal wall seen on one but not the other scan. At chart review, we recorded patient demographics and other clinical characteristics (prior surgical history, presence of cirrhosis). Results: An intermittently upturned omentum was found in 10 of 336 (3.0%) patients. An intermittently upturned omentum was seen more commonly in men than in women (9 of 189 men, or 4.8% versus 1 of 147 women, or 0.7%, p = 0.047) and in cirrhotics (4 of 37 cirrhotics, or 10.8% versus 6 of 299 non-cirrhotics, or 2.0%, p = 0.023). In a sub-analysis of patients without prior abdominal surgery, this finding was again seen more commonly in men than women (7 of 163 men, or 4.3% versus 0 of 134 women, or 0%, p = 0.018) and in cirrhotics (3 of 33 cirrhotics, or 9.1% versus 4 of 264 non-cirrhotics, or 1.5%, p = 0.032). Conclusions: An intermittently upturned omentum is not uncommon and is more frequently seen in men and in patients with cirrhosis who may have a larger anterior hepatic space.

Demographics and frequency of the intermittently upturned omentum at CT

International Nuclear Information System (INIS)

Penn, Alex; Wang, Wilbur; Wang, Zhen Jane; Yee, Judy; Webb, Emily M.; Yeh, Benjamin M.

2013-01-01

Objectives: To describe the demographics and frequency of the intermittently upturned omentum at CT. Methods: We retrospectively reviewed abdominal CT scans of 336 consecutive patients (189 men and 147 women) who were imaged between June 1 and June 17, 2010 and who had prior comparison scans. Readers recorded the presence or absence of an intermittently upturned omentum, defined as a thick rind of fat interposed between the liver and the anterior abdominal wall seen on one but not the other scan. At chart review, we recorded patient demographics and other clinical characteristics (prior surgical history, presence of cirrhosis). Results: An intermittently upturned omentum was found in 10 of 336 (3.0%) patients. An intermittently upturned omentum was seen more commonly in men than in women (9 of 189 men, or 4.8% versus 1 of 147 women, or 0.7%, p = 0.047) and in cirrhotics (4 of 37 cirrhotics, or 10.8% versus 6 of 299 non-cirrhotics, or 2.0%, p = 0.023). In a sub-analysis of patients without prior abdominal surgery, this finding was again seen more commonly in men than women (7 of 163 men, or 4.3% versus 0 of 134 women, or 0%, p = 0.018) and in cirrhotics (3 of 33 cirrhotics, or 9.1% versus 4 of 264 non-cirrhotics, or 1.5%, p = 0.032). Conclusions: An intermittently upturned omentum is not uncommon and is more frequently seen in men and in patients with cirrhosis who may have a larger anterior hepatic space

29 CFR 825.203 - Scheduling of intermittent or reduced schedule leave.

Science.gov (United States)

2010-07-01

... leave intermittently or on a reduced leave schedule for planned medical treatment, then the employee... 29 Labor 3 2010-07-01 2010-07-01 false Scheduling of intermittent or reduced schedule leave. 825... OF LABOR OTHER LAWS THE FAMILY AND MEDICAL LEAVE ACT OF 1993 Employee Leave Entitlements Under the...

Boldness and intermittent locomotion in the bluegill sunfish, Lepomis macrochirus

OpenAIRE

Alexander D.M. Wilson; Jean-Guy J. Godin

2009-01-01

Intermittent locomotion, characterized by moves interspersed with pauses, is a common pattern of locomotion in animals, but its ecological and evolutionary significance relative to continuous locomotion remains poorly understood. Although many studies have examined individual differences in both intermittent locomotion and boldness separately, to our knowledge, no study to date has investigated the relationship between these 2 traits. Characterizing and understanding this relationship is impo...

Dispatching Plan Based on Route Optimization Model Considering Random Wind for Aviation Emergency Rescue

Directory of Open Access Journals (Sweden)

Ming Zhang

2016-01-01

Full Text Available Aviation emergency rescue is an effective means of nature disaster relief that is widely used in many countries. The dispatching plan of aviation emergency rescue guarantees the efficient implementation of this relief measure. The conventional dispatching plan that does not consider random wind factors leads to a nonprecise quick-responsive scheme and serious safety issues. In this study, an aviation emergency rescue framework that considers the influence of random wind at flight trajectory is proposed. In this framework, the predicted wind information for a disaster area is updated by using unscented Kalman filtering technology. Then, considering the practical scheduling problem of aircraft emergency rescue at present, a multiobjective model is established in this study. An optimization model aimed at maximizing the relief supply satisfaction, rescue priority satisfaction, and minimizing total rescue flight distance is formulated. Finally, the transport times of aircraft with and without the influence of random wind are analyzed on the basis of the data of an earthquake disaster area. Results show that the proposed dispatching plan that considers the constraints of updated wind speed and direction is highly applicable in real operations.

Muscle involvement during intermittent contraction patterns with different target force feedback modes

DEFF Research Database (Denmark)

Sjøgaard, G; Jørgensen, L V; Ekner, D

2000-01-01

and following 30 min of intermittent contractions showed larger fatigue development with proprioceptive feedback than visual feedback. Also rating of perceived exertion increased more during proprioceptive feedback than visual feedback. This may in part be explained by small differences in the mechanics during......: Feedback mode significantly effects the muscle involvement and fatigue during intermittent contractions. RelevanceIntermittent contractions are common in many work places and various feedback modes are being given regarding work requirements. The choice of feedback may significantly affect the muscle load...... and consequently the development muscle fatigue and disorders....

Health effects of intermittent fasting: hormesis or harm? A systematic review.

Science.gov (United States)

Horne, Benjamin D; Muhlestein, Joseph B; Anderson, Jeffrey L

2015-08-01

Intermittent fasting, alternate-day fasting, and other forms of periodic caloric desistance are gaining popularity in the lay press and among animal research scientists. Whether clinical evidence exists for or is strong enough to support the use of such dietary regimens as health interventions is unclear. This review sought to identify rigorous, clinically relevant research studies that provide high-quality evidence that therapeutic fasting regimens are clinically beneficial to humans. A systematic review of the published literature through January 2015 was performed by using sensitive search strategies to identify randomized controlled clinical trials that evaluated the effects of fasting on either clinically relevant surrogate outcomes (e.g., weight, cholesterol) or actual clinical event endpoints [e.g., diabetes, coronary artery disease (CAD)] and any other studies that evaluated the effects of fasting on clinical event outcomes. Three randomized controlled clinical trials of fasting in humans were identified, and the results were published in 5 articles, all of which evaluated the effects of fasting on surrogate outcomes. Improvements in weight and other risk-related outcomes were found in the 3 trials. Two observational clinical outcomes studies in humans were found in which fasting was associated with a lower prevalence of CAD or diabetes diagnosis. No randomized controlled trials of fasting for clinical outcomes were identified. Clinical research studies of fasting with robust designs and high levels of clinical evidence are sparse in the literature. Whereas the few randomized controlled trials and observational clinical outcomes studies support the existence of a health benefit from fasting, substantial further research in humans is needed before the use of fasting as a health intervention can be recommended. © 2015 American Society for Nutrition.

Intermittent Hypoxia in Childhood: The Harmful Consequences Versus Potential Benefits of Therapeutic Uses

OpenAIRE

Serebrovskaya, Tatiana V.; Xi, Lei

2015-01-01

Intermittent hypoxia often occurs in early infancy in both preterm and term infants and especially at 36 to 44 weeks postmenstrual age. These episodes of intermittent hypoxia could result from sleep-disordered breathing or may be temporally unrelated to apnea or bradycardia events. There are numerous reports indicating adverse effects of intermittent hypoxia on development, behavior, academic achievement and cognition in children with sleep apnea syndrome. It remains uncertain the exact causa...

Initial treatment of respiratory distress syndrome with nasal intermittent mandatory ventilation versus nasal continuous positive airway pressure: A randomized controlled trial

Directory of Open Access Journals (Sweden)

Amir-Mohammad Armanian

2014-01-01

Full Text Available Background: Neonatal respiratory distress syndrome (RDS in premature infants who survived and its complications are a common problem. Due to high morbidity and mechanical ventilation (MV nowadays researchers in interested minimizing MV. To determine, in very low birth weight (BW preterm neonates with RDS, if initial treatment with nasal intermittent mandatory ventilation (early NIMV compared with early nasal continuous positive airway pressure (early NCPAP obtains more favorable outcomes in terms of the duration of treatment, and the need for endotracheal tube ventilation. Methods: In this single-center randomized control trial study, infants (BW ≤ 1500 g and/or gestational age ≤ 34 weeks with respiratory distress were considered eligible. Forty-four infants were randomly assigned to receive early-NIMV and 54 comparable infants to early-NCPAP. Surfactants were given, when FIO 2 requirement was of >30%. Primary outcomes were failure of noninvasive respiratory support, that is, the need for MV in the first 48 h of life and for the duration of noninvasive respiratory support in each group. Results: 98 infants were enrolled (44 in the NIMV and 54 in the NCPAP group. The Preventive power of MV of NIMV usage (95.5% was not lower than the NCPAP (98.1% strength (hazard ratio: 0.21 (95% confidence interval: 0.02-2.66; P: 0.23. The duration of noninvasive respiratory support in the NIMV group was significantly shorter than NCPAP (the median (range was 24 (18.00-48.00 h versus 48.00 (22.00-120.00 h in NIMV versus NCPAP groups; P < 0.001. Similarly, the duration of dependency on oxygen was less, for NIMV (the median (range was 96.00 (41.00-504.00 h versus144.00 (70.00-1130.00 h in NIMV versus NCPAP groups; P: 0.009. Interestingly, time to full enteral feeds and length of hospital stay were more favorable in the NIMV versus the NCPAP group. Conclusions: Initial treatment of RDS with NIMV was safe, and well tolerated. Furthermore, NIMV had excellent

Angiotensin-(1?7) inhibits inflammation and oxidative stress to relieve lung injury induced by chronic intermittent hypoxia in rats

OpenAIRE

Lu, W.; Kang, J.; Hu, K.; Tang, S.; Zhou, X.; Yu, S.; Li, Y.; Xu, L.

2016-01-01

Obstructive sleep apnea is associated with inflammation and oxidative stress in lung tissues and can lead to metabolic abnormalities. We investigated the effects of angiotensin1–7 [Ang-(1–7)] on lung injury in rats induced by chronic intermittent hypoxia (CIH). We randomly assigned 32 male Sprague-Dawley rats (180–200 g) to normoxia control (NC), CIH-untreated (uCIH), Ang-(1–7)-treated normoxia control (N-A), and Ang-(1–7)-treated CIH (CIH-A) groups. Oxidative stress biomarkers were measured ...

Intermittent search strategies revisited: effect of the jump length and biased motion

Energy Technology Data Exchange (ETDEWEB)

Rojo, F; Budde, C E [Fa.M.A.F., Universidad Nacional de Cordoba, Ciudad Universitaria, X5000HUA Cordoba (Argentina); Revelli, J; Wio, H S [Instituto de Fisica de Cantabria, Universidad de Cantabria and CSIC, E-39005 Santander (Spain); Oshanin, G [Laboratoire de Physique Theorique de la Matiere Condensee, Universite Pierre et Marie Curie, 4 place Jussieu, 75252 Paris Cedex 5 (France); Lindenberg, Katja [Department of Chemistry and Biochemistry and BioCircuits Institute, University of California, San Diego, La Jolla, CA 92093-0340 (United States)

2010-08-27

We study the kinetics of a search of a single fixed target by a large number of searchers performing an intermittent biased random walk in a homogeneous medium. Our searchers carry out their walks in one of two states between which they switch randomly. One of these states (search phase) is a nearest-neighbor walk characterized by the probability of stepping in a given direction (i.e. the walks in this state are not necessarily isotropic). The other (relocation phase) is characterized by the length of the jumps (i.e. when in this state a walker does not perform a nearest-neighbor walk). Within such a framework, we propose a model to describe the searchers' dynamics, generalizing results of our previous work. We have obtained, and numerically evaluated, analytic results for the mean number of distinct sites visited up to a maximum evolution time. We have studied the dependence of this quantity on both the transition probability between the states and the parameters that characterize each state. In addition to our theoretical approach, we have implemented Monte Carlo simulations, finding excellent agreement between the theoretical-numerical and simulations results.

Intermittent search strategies revisited: effect of the jump length and biased motion

International Nuclear Information System (INIS)

Rojo, F; Budde, C E; Revelli, J; Wio, H S; Oshanin, G; Lindenberg, Katja

2010-01-01

We study the kinetics of a search of a single fixed target by a large number of searchers performing an intermittent biased random walk in a homogeneous medium. Our searchers carry out their walks in one of two states between which they switch randomly. One of these states (search phase) is a nearest-neighbor walk characterized by the probability of stepping in a given direction (i.e. the walks in this state are not necessarily isotropic). The other (relocation phase) is characterized by the length of the jumps (i.e. when in this state a walker does not perform a nearest-neighbor walk). Within such a framework, we propose a model to describe the searchers' dynamics, generalizing results of our previous work. We have obtained, and numerically evaluated, analytic results for the mean number of distinct sites visited up to a maximum evolution time. We have studied the dependence of this quantity on both the transition probability between the states and the parameters that characterize each state. In addition to our theoretical approach, we have implemented Monte Carlo simulations, finding excellent agreement between the theoretical-numerical and simulations results.

EVOLUTION OF INTERMITTENCY IN THE SLOW AND FAST SOLAR WIND BEYOND THE ECLIPTIC PLANE

International Nuclear Information System (INIS)

Wawrzaszek, A.; Macek, W. M.; Echim, M.; Bruno, R.

2015-01-01

We study intermittency as a departure from self-similarity of the solar wind magnetic turbulence and investigate the evolution with the heliocentric distance and latitude. We use data from the Ulysses spacecraft measured during two solar minima (1997–1998 and 2007–2008) and one solar maximum (1999–2001). In particular, by modeling a multifractal spectrum, we revealed the intermittent character of turbulence in the small-scale fluctuations of the magnetic field embedded in the slow and fast solar wind. Generally, at small distances from the Sun, in both the slow and fast solar wind, we observe the high degree of multifractality (intermittency) that decreases somewhat slowly with distance and slowly with latitude. The obtained results seem to suggest that generally intermittency in the solar wind has a solar origin. However, the fast and slow streams, shocks, and other nonlinear interactions can only be considered as the drivers of the intermittent turbulence. It seems that analysis shows that turbulence beyond the ecliptic plane evolves too slowly to maintain the intermittency with the distance and latitude. Moreover, we confirm that the multifractality and intermittency are at a lower level than in the ecliptic, as well as the existence of symmetry with respect to the ecliptic plane, suggesting that there are similar turbulent properties observed in the two hemispheres

EVOLUTION OF INTERMITTENCY IN THE SLOW AND FAST SOLAR WIND BEYOND THE ECLIPTIC PLANE

Energy Technology Data Exchange (ETDEWEB)

Wawrzaszek, A.; Macek, W. M. [Space Research Centre, Polish Academy of Sciences, Warsaw (Poland); Echim, M. [The Belgian Institute for Space Aeronomy, Brussels (Belgium); Bruno, R., E-mail: anna.wawrzaszek@cbk.waw.pl, E-mail: marius.echim@oma.be, E-mail: macek@cbk.waw.pl, E-mail: roberto.bruno@iaps.inaf.it [Institute for Space Astrophysics and Planetology, Roma (Italy)

2015-12-01

We study intermittency as a departure from self-similarity of the solar wind magnetic turbulence and investigate the evolution with the heliocentric distance and latitude. We use data from the Ulysses spacecraft measured during two solar minima (1997–1998 and 2007–2008) and one solar maximum (1999–2001). In particular, by modeling a multifractal spectrum, we revealed the intermittent character of turbulence in the small-scale fluctuations of the magnetic field embedded in the slow and fast solar wind. Generally, at small distances from the Sun, in both the slow and fast solar wind, we observe the high degree of multifractality (intermittency) that decreases somewhat slowly with distance and slowly with latitude. The obtained results seem to suggest that generally intermittency in the solar wind has a solar origin. However, the fast and slow streams, shocks, and other nonlinear interactions can only be considered as the drivers of the intermittent turbulence. It seems that analysis shows that turbulence beyond the ecliptic plane evolves too slowly to maintain the intermittency with the distance and latitude. Moreover, we confirm that the multifractality and intermittency are at a lower level than in the ecliptic, as well as the existence of symmetry with respect to the ecliptic plane, suggesting that there are similar turbulent properties observed in the two hemispheres.

Development of an optimized random amplified polymorphic DNA protocol for fingerprinting of Klebsiella pneumoniae.

Science.gov (United States)

Ashayeri-Panah, M; Eftekhar, F; Feizabadi, M M

2012-04-01

To develop an optimized random amplified polymorphic DNA (RAPD) protocol for fingerprinting clinical isolates of Klebsiella pneumoniae. Employing factorial design of experiments, repeatable amplification patterns were obtained for 54 nosocomial isolates using 1 μmol 1(-1) primer, 4 mmol 1(-1) MgCl(2), 0·4 mmol 1(-1) dNTPs, 2·5 U Taq DNA polymerase and 90 ng DNA template in a total volume of 25 μl. The optimum thermocycling program was: initial denaturation at 94°C for 4 min followed by 50 cycles of 1 min at 94°C, 2 min at 34°C, 2 min at 72°C and a final extension at 72°C for 10 min. The optimized RAPD protocol was highly discriminatory (Simpson's diversity index, 0·982), and all isolates were typable with repeatable patterns (Pearson's similarity coefficient ≈ 100%). Seven main clusters were obtained on a similarity level of 70% and 32 distinct clusters on a similarity level of 85%, reflecting the heterogeneity of the isolates. Systematic optimization of RAPD generated reliable DNA fingerprints for nosocomial isolates of K. pneumoniae. This is the first report on RAPD optimization based on factorial design of experiments for discrimination of K. pneumoniae. © 2012 The Authors. Letters in Applied Microbiology © 2012 The Society for Applied Microbiology.

Economic intermittency in a two-country model of business cycles coupled by investment

Energy Technology Data Exchange (ETDEWEB)

Saiki, Y., E-mail: saiki@math.sci.hokudai.ac.jp [Department of Mathematics, Hokkaido University, Sapporo 060-0810 (Japan); Chian, A.C.L. [National Institute for Space Research (INPE) and World Institute for Space Environment Research (WISER), P.O. Box 515, Sao Jose dos Campos-SP 12227-010 (Brazil); California Institute of Technology, Pasadena, CA 91125 (United States); Yoshida, H. [College of Economics, Nihon University, Tokyo 101-8360 (Japan)

2011-06-15

Highlights: > Intermittent economic behavior of Keynes-Goodwin type model is investigated. > After a transition the system keeps its memory before the transition. > The intermittent phenomena is examined from the business cycle patterns. > It is concluded that dynamical patterns do not alter much around the transition. - Abstract: Intermittent behavior of economic dynamics is investigated by a two-country model of Keynes-Goodwin type business cycles. Numerical simulations show that after an economic system evolves from weak chaos to strong chaos the system keeps its memory before the transition and its time series alternates episodically between periods of weakly and strongly chaotic fluctuations. In addition, we examine the intermittent phenomena from the view point of business cycle patterns near the crisis point.

Economic intermittency in a two-country model of business cycles coupled by investment

International Nuclear Information System (INIS)

Saiki, Y.; Chian, A.C.L.; Yoshida, H.

2011-01-01

Highlights: → Intermittent economic behavior of Keynes-Goodwin type model is investigated. → After a transition the system keeps its memory before the transition. → The intermittent phenomena is examined from the business cycle patterns. → It is concluded that dynamical patterns do not alter much around the transition. - Abstract: Intermittent behavior of economic dynamics is investigated by a two-country model of Keynes-Goodwin type business cycles. Numerical simulations show that after an economic system evolves from weak chaos to strong chaos the system keeps its memory before the transition and its time series alternates episodically between periods of weakly and strongly chaotic fluctuations. In addition, we examine the intermittent phenomena from the view point of business cycle patterns near the crisis point.

Intermittent characteristics in coupling between turbulence and zonal flows

International Nuclear Information System (INIS)

Fujisawa, A; Shimizu, A; Nakano, H; Ohshima, S; Itoh, K; Nagashima, Y; Itoh, S-I; Iguchi, H; Yoshimura, Y; Minami, T; Nagaoka, K; Takahashi, C; Kojima, M; Nishimura, S; Isobe, M; Suzuki, C; Akiyama, T; Ido, T; Matsuoka, K; Okamura, S; Diamond, P H

2007-01-01

An extended application of Gabour's wavelet to bicoherence analysis succeeds in resolving the instantaneous structure of three wave couplings between disparate scale electric field fluctuations in the high temperature core in a toroidal plasma device named the compact helical system. The obtained results quantify an intermittent linkage between turbulence and zonal flows-a highlighted issue in the present plasma research. This is the first demonstration that the intermittent nature of the three wave coupling should underlie the turbulence power modulation due to zonal flows

Management of patients with intermittent claudication

NARCIS (Netherlands)

S. Spronk (Sandra)

2008-01-01

textabstractIntermittent claudication is the first and mildest manifestation of peripheral arterial disease, caused by the atherosclerotic process of progressive narrowing of one or more of the arteries of the peripheral circulation.1 If the arterial system fails, it results in a progressive oxygen

Circulating, cell-free DNA as a marker for exercise load in intermittent sports

OpenAIRE

Haller, Nils; Helmig, Susanne; Taenny, Pascal; Petry, Julian; Schmidt, Sebastian; Simon, Perikles

2018-01-01

Background Attempts to establish a biomarker reflecting individual player load in intermittent sports such as football have failed so far. Increases in circulating DNA (cfDNA) have been demonstrated in various endurance sports settings. While it has been proposed that cfDNA could be a suitable marker for player load in intermittent sports, the effects on cfDNA of repeated sprinting as an essential feature in intermittent sports are unknown. For the first time, we assessed both alterations of ...

Intermittent dynamics of nonlinear resistive tearing modes at extremely high magnetic Reynolds number

International Nuclear Information System (INIS)

Miyoshi, Takahiro; Becchaku, Masahiro; Kusano, Kanya

2008-01-01

Nonlinear dynamics of the resistive tearing instability in high magnetic Reynolds number (R m ) plasmas is studied by newly developing an accurate and robust resistive magnetohydrodynamic (MHD) scheme. The results show that reconnection processes strongly depend on R m . Particularly, in a high R m case, small-scale plasmoids induced by a secondary instability are intermittently generated and ejected accompanied by fast shocks. According to the intermittent processes, the reconnection rate increases intermittently at a later nonlinear stage. (author)

Structure functions and intermittency in ionospheric plasma turbulence

Directory of Open Access Journals (Sweden)

L. Dyrud

2008-11-01

Full Text Available Low frequency electrostatic turbulence in the ionospheric E-region is studied by means of numerical and experimental methods. We use the structure functions of the electrostatic potential as a diagnostics of the fluctuations. We demonstrate the inherently intermittent nature of the low level turbulence in the collisional ionospheric plasma by using results for the space-time varying electrostatic potential from two dimensional numerical simulations. An instrumented rocket can not directly detect the one-point potential variation, and most measurements rely on records of potential differences between two probes. With reference to the space observations we demonstrate that the results obtained by potential difference measurements can differ significantly from the one-point results. It was found, in particular, that the intermittency signatures become much weaker, when the proper rocket-probe configuration is implemented. We analyze also signals from an actual ionospheric rocket experiment, and find a reasonably good agreement with the appropriate simulation results, demonstrating again that rocket data, obtained as those analyzed here, are unlikely to give an adequate representation of intermittent features of the low frequency ionospheric plasma turbulence for the given conditions.

Model and analysis of solar thermal generators to reduce the intermittency of photovoltaic systems with the use of spectrum splitting

Science.gov (United States)

Ayala, Silvana; Wu, Yuechen; Vorndran, Shelby; Santiago, Raphael P.; Kostuk, Raymond K.

2015-09-01

In this paper we introduce an approach to damping intermittency in photovoltaic (PV) system output due to fluctuations in solar illumination generated by use of a hybrid PV-thermal electric (TE) generation system. We describe the necessary constrains of the PV-TE system based on its thermodynamic characteristics. The basis for the approach is that the thermal time constant for the TE device is much longer than that of a PV cell. When used in combination with an optimized thermal storage device short periods of intermittency (several minutes) in PV output due to passing clouds can be compensated. A comparison of different spectrum splitting systems to efficiently utilize the incident solar spectrum between the PV and TE converters are also examined. The time-dependent behavior of a hybrid PV-TE converter with a thermal storage element is computed with SMARTS modeled irradiance data and compared to real weather and irradiation conditions for Tucson, Arizona.

Chronic intermittent hypoxia preserves bone density in a mouse model of sleep apnea.

Science.gov (United States)

Torres, Marta; Montserrat, Josep M; Pavía, Javier; Dalmases, Mireia; Ros, Domenec; Fernandez, Yolanda; Barbé, Ferran; Navajas, Daniel; Farré, Ramon

2013-12-01

Very recent clinical research has investigated whether obstructive sleep apnea (OSA) may modulate bone homeostasis but the few data available are conflicting. Here we report novel data obtained in a mouse study specifically designed to determine whether chronic intermittent hypoxia realistically mimicking OSA modifies bone mineral density (BMD). Normal male and female mice and orchidectomized mice (N=10 each group) were subjected to a pattern of high-frequency intermittent hypoxia (20s at 5% and 40s at 21%, 60 cycles/h) for 6h/day. Identical groups breathing room air (normoxia) were the controls. After 32 days of intermittent hypoxia/normoxia the trabecular bone mineral density (BMD) in the peripheral femora were measured by micro-CT scanning. When compared with normoxia (two-way ANOVA), intermittent hypoxia did not significantly modify BMD in the three animal groups tested. Data in this study suggest that the type of intermittent hypoxia characterizing OSA, applied as a single challenge, preserves bone homeostasis. Copyright © 2013 Elsevier B.V. All rights reserved.

External intermittency prediction using AMR solutions of RANS turbulence and transported PDF models

Science.gov (United States)

Olivieri, D. A.; Fairweather, M.; Falle, S. A. E. G.

2011-12-01

External intermittency in turbulent round jets is predicted using a Reynolds-averaged Navier-Stokes modelling approach coupled to solutions of the transported probability density function (pdf) equation for scalar variables. Solutions to the descriptive equations are obtained using a finite-volume method, combined with an adaptive mesh refinement algorithm, applied in both physical and compositional space. This method contrasts with conventional approaches to solving the transported pdf equation which generally employ Monte Carlo techniques. Intermittency-modified eddy viscosity and second-moment turbulence closures are used to accommodate the effects of intermittency on the flow field, with the influence of intermittency also included, through modifications to the mixing model, in the transported pdf equation. Predictions of the overall model are compared with experimental data on the velocity and scalar fields in a round jet, as well as against measurements of intermittency profiles and scalar pdfs in a number of flows, with good agreement obtained. For the cases considered, predictions based on the second-moment turbulence closure are clearly superior, although both turbulence models give realistic predictions of the bimodal scalar pdfs observed experimentally.

Quasistatic Dynamics with Intermittency

International Nuclear Information System (INIS)

Leppänen, Juho; Stenlund, Mikko

2016-01-01

We study an intermittent quasistatic dynamical system composed of nonuniformly hyperbolic Pomeau–Manneville maps with time-dependent parameters. We prove an ergodic theorem which shows almost sure convergence of time averages in a certain parameter range, and identify the unique physical family of measures. The theorem also shows convergence in probability in a larger parameter range. In the process, we establish other results that will be useful for further analysis of the statistical properties of the model.

Quasistatic Dynamics with Intermittency

Energy Technology Data Exchange (ETDEWEB)

Leppänen, Juho; Stenlund, Mikko, E-mail: mikko.stenlund@helsinki.fi [University of Helsinki, Department of Mathematics and Statistics (Finland)

2016-06-15

We study an intermittent quasistatic dynamical system composed of nonuniformly hyperbolic Pomeau–Manneville maps with time-dependent parameters. We prove an ergodic theorem which shows almost sure convergence of time averages in a certain parameter range, and identify the unique physical family of measures. The theorem also shows convergence in probability in a larger parameter range. In the process, we establish other results that will be useful for further analysis of the statistical properties of the model.

Dealing with uncertainty in modeling intermittent water supply

Science.gov (United States)

Lieb, A. M.; Rycroft, C.; Wilkening, J.

2015-12-01

Intermittency in urban water supply affects hundreds of millions of people in cities around the world, impacting water quality and infrastructure. Building on previous work to dynamically model the transient flows in water distribution networks undergoing frequent filling and emptying, we now consider the hydraulic implications of uncertain input data. Water distribution networks undergoing intermittent supply are often poorly mapped, and household metering frequently ranges from patchy to nonexistent. In the face of uncertain pipe material, pipe slope, network connectivity, and outflow, we investigate how uncertainty affects dynamical modeling results. We furthermore identify which parameters exert the greatest influence on uncertainty, helping to prioritize data collection.

White adipose tissue coloring by intermittent fasting.

Science.gov (United States)

Kivelä, Riikka; Alitalo, Kari

2017-11-01

Intermittent fasting (IF) has been shown to promote metabolic health in several organisms. Two recent papers show that IF induces white adipose tissue beiging and increases thermogenesis, which improves metabolic health in mice.

Generation and monitoring of a discrete stable random process

CERN Document Server

Hopcraft, K I; Matthews, J O

2002-01-01

A discrete stochastic process with stationary power law distribution is obtained from a death-multiple immigration population model. Emigrations from the population form a random series of events which are monitored by a counting process with finite-dynamic range and response time. It is shown that the power law behaviour of the population is manifested in the intermittent behaviour of the series of events. (letter to the editor)

Evaluation of educational content of YouTube videos relating to neurogenic bladder and intermittent catheterization.

Science.gov (United States)

Ho, Matthew; Stothers, Lynn; Lazare, Darren; Tsang, Brian; Macnab, Andrew

2015-01-01

Many patients conduct internet searches to manage their own health problems, to decide if they need professional help, and to corroborate information given in a clinical encounter. Good information can improve patients' understanding of their condition and their self-efficacy. Patients with spinal cord injury (SCI) featuring neurogenic bladder (NB) require knowledge and skills related to their condition and need for intermittent catheterization (IC). Information quality was evaluated in videos accessed via YouTube relating to NB and IC using search terms "neurogenic bladder intermittent catheter" and "spinal cord injury intermittent catheter." Video content was independently rated by 3 investigators using criteria based on European Urological Association (EAU) guidelines and established clinical practice. In total, 71 videos met the inclusion criteria. Of these, 12 (17%) addressed IC and 50 (70%) contained information on NB. The remaining videos met inclusion criteria, but did not contain information relevant to either IC or NB. Analysis indicated poor overall quality of information, with some videos with information contradictory to EAU guidelines for IC. High-quality videos were randomly distributed by YouTube. IC videos featuring a healthcare narrator scored significantly higher than patient-narrated videos, but not higher than videos with a merchant narrator. About half of the videos contained commercial content. Some good-quality educational videos about NB and IC are available on YouTube, but most are poor. The videos deemed good quality were not prominently ranked by the YouTube search algorithm, consequently user access is less likely. Study limitations include the limit of 50 videos per category and the use of a de novo rating tool. Information quality in videos with healthcare narrators was not higher than in those featuring merchant narrators. Better material is required to improve patients' understanding of their condition.

Male fertility is reduced by chronic intermittent hypoxia mimicking sleep apnea in mice.

Science.gov (United States)

Torres, Marta; Laguna-Barraza, Ricardo; Dalmases, Mireia; Calle, Alexandra; Pericuesta, Eva; Montserrat, Josep M; Navajas, Daniel; Gutierrez-Adan, Alfonso; Farré, Ramon

2014-11-01

Obstructive sleep apnea (OSA) is characterized by intermittent hypoxia and oxidative stress. However, it is unknown whether intermittent hypoxia mimicking OSA modifies male fertility. We tested the hypothesis that male fertility is reduced by chronic intermittent hypoxia mimicking OSA in a mouse model. Case-control comparison in a murine model. University research laboratory. Eighteen F1 (C57BL/6xCBA) male mice. Mice were subjected to a pattern of periodic hypoxia (20 sec at 5% O2 followed by 40 sec of room air) 6 h/day for 60 days or normoxia. After this period, mice performed a mating trial to determine effective fertility by assessing the number of pregnant females and fetuses. After euthanasia, oxidative stress in testes was assessed by measuring the expression of glutathione peroxidase 1 (Gpx1) and superoxide dismutase-1 (Sod1) by reverse-transcription polymerase chain reaction. Sperm motility was determined by Integrated Semen Analysis System (ISAS). Intermittent hypoxia significantly increased testicular oxidative stress, showing a reduction in the expression of Gpx1 and Sod1 by 38.9% and 34.4%, respectively, as compared with normoxia (P intermittent hypoxia group (P = 0.04). The proportion of pregnant females and number of fetuses per mating was significantly lower in the intermittent hypoxia group (0.33 ± 0.10 and 2.45 ± 0.73, respectively) than in normoxic controls (0.72 ± 0.16 and 5.80 ± 1.24, respectively). These results suggest that the intermittent hypoxia associated with obstructive sleep apnea (OSA) could induce fertility reduction in male patients with this sleep breathing disorder.

Smoking Patterns and Stimulus Control in Intermittent and Daily Smokers

Science.gov (United States)

Shiffman, Saul; Dunbar, Michael S.; Li, Xiaoxue; Scholl, Sarah M.; Tindle, Hilary A.; Anderson, Stewart J.; Ferguson, Stuart G.

2014-01-01

Intermittent smokers (ITS) – who smoke less than daily – comprise an increasing proportion of adult smokers. Their smoking patterns challenge theoretical models of smoking motivation, which emphasize regular and frequent smoking to maintain nicotine levels and avoid withdrawal, but yet have gone largely unexamined. We characterized smoking patterns among 212 ITS (smoking 4–27 days per month) compared to 194 daily smokers (DS; smoking 5–30 cigarettes daily) who monitored situational antecedents of smoking using ecological momentary assessment. Subjects recorded each cigarette on an electronic diary, and situational variables were assessed in a random subset (n = 21,539 smoking episodes); parallel assessments were obtained by beeping subjects at random when they were not smoking (n = 26,930 non-smoking occasions). Compared to DS, ITS' smoking was more strongly associated with being away from home, being in a bar, drinking alcohol, socializing, being with friends and acquaintances, and when others were smoking. Mood had only modest effects in either group. DS' and ITS' smoking were substantially and equally suppressed by smoking restrictions, although ITS more often cited self-imposed restrictions. ITS' smoking was consistently more associated with environmental cues and contexts, especially those associated with positive or “indulgent” smoking situations. Stimulus control may be an important influence in maintaining smoking and making quitting difficult among ITS. PMID:24599056

Smoking patterns and stimulus control in intermittent and daily smokers.

Directory of Open Access Journals (Sweden)

Saul Shiffman

Full Text Available Intermittent smokers (ITS - who smoke less than daily - comprise an increasing proportion of adult smokers. Their smoking patterns challenge theoretical models of smoking motivation, which emphasize regular and frequent smoking to maintain nicotine levels and avoid withdrawal, but yet have gone largely unexamined. We characterized smoking patterns among 212 ITS (smoking 4-27 days per month compared to 194 daily smokers (DS; smoking 5-30 cigarettes daily who monitored situational antecedents of smoking using ecological momentary assessment. Subjects recorded each cigarette on an electronic diary, and situational variables were assessed in a random subset (n=21,539 smoking episodes; parallel assessments were obtained by beeping subjects at random when they were not smoking (n=26,930 non-smoking occasions. Compared to DS, ITS' smoking was more strongly associated with being away from home, being in a bar, drinking alcohol, socializing, being with friends and acquaintances, and when others were smoking. Mood had only modest effects in either group. DS' and ITS' smoking were substantially and equally suppressed by smoking restrictions, although ITS more often cited self-imposed restrictions. ITS' smoking was consistently more associated with environmental cues and contexts, especially those associated with positive or "indulgent" smoking situations. Stimulus control may be an important influence in maintaining smoking and making quitting difficult among ITS.

Random broadcast on random geometric graphs

Energy Technology Data Exchange (ETDEWEB)

Bradonjic, Milan [Los Alamos National Laboratory; Elsasser, Robert [UNIV OF PADERBORN; Friedrich, Tobias [ICSI/BERKELEY; Sauerwald, Tomas [ICSI/BERKELEY

2009-01-01

In this work, we consider the random broadcast time on random geometric graphs (RGGs). The classic random broadcast model, also known as push algorithm, is defined as: starting with one informed node, in each succeeding round every informed node chooses one of its neighbors uniformly at random and informs it. We consider the random broadcast time on RGGs, when with high probability: (i) RGG is connected, (ii) when there exists the giant component in RGG. We show that the random broadcast time is bounded by {Omicron}({radical} n + diam(component)), where diam(component) is a diameter of the entire graph, or the giant component, for the regimes (i), or (ii), respectively. In other words, for both regimes, we derive the broadcast time to be {Theta}(diam(G)), which is asymptotically optimal.

Cooling tower modification for intermittent operation

International Nuclear Information System (INIS)

Midkiff, W.S.

1975-03-01

One of the cooling towers at Los Alamos Scientific Laboratory is being operated intermittently. The cooling tower has been modified to restrict air flow and to keep the tower from drying out. The modifications are relatively inexpensive, simple to operate, and have proved effective. (U.S.)

Multi-scale magnetic field intermittence in the plasma sheet

Directory of Open Access Journals (Sweden)

Z. Vörös

2003-09-01

Full Text Available This paper demonstrates that intermittent magnetic field fluctuations in the plasma sheet exhibit transitory, localized, and multi-scale features. We propose a multifractal-based algorithm, which quantifies intermittence on the basis of the statistical distribution of the "strength of burstiness", estimated within a sliding window. Interesting multi-scale phenomena observed by the Cluster spacecraft include large-scale motion of the current sheet and bursty bulk flow associated turbulence, interpreted as a cross-scale coupling (CSC process.Key words. Magnetospheric physics (magnetotail; plasma sheet – Space plasma physics (turbulence

Neuromodulation of Limb Proprioceptive Afferents Decreases Apnea of Prematurity and Accompanying Intermittent Hypoxia and Bradycardia.

Science.gov (United States)

Kesavan, Kalpashri; Frank, Paul; Cordero, Daniella M; Benharash, Peyman; Harper, Ronald M

2016-01-01

Apnea of Prematurity (AOP) is common, affecting the majority of infants born at Apnea and periodic breathing are accompanied by intermittent hypoxia (IH). Animal and human studies demonstrate that IH exposure contributes to multiple pathologies, including retinopathy of prematurity (ROP), injury to sympathetic ganglia regulating cardiovascular action, impaired pancreatic islet cell and bone development, cerebellar injury, and neurodevelopmental disabilities. Current standard of care for AOP/IH includes prone positioning, positive pressure ventilation, and methylxanthine therapy; these interventions are inadequate, and not optimal for early development. The objective is to support breathing in premature infants by using a simple, non-invasive vibratory device placed over limb proprioceptor fibers, an intervention using the principle that limb movements trigger reflexive facilitation of breathing. Premature infants (23-34 wks gestational age), with clinical evidence of AOP/IH episodes were enrolled 1 week after birth. Caffeine treatment was not a reason for exclusion. Small vibration devices were placed on one hand and one foot and activated in 6 hour ON/OFF sequences for a total of 24 hours. Heart rate, respiratory rate, oxygen saturation (SpO2), and breathing pauses were continuously collected. Fewer respiratory pauses occurred during vibration periods, relative to baseline (papnea, bradycardia and intermittent hypoxia in premature neonates. ClinicalTrials.gov NCT02641249.

Feigenbaum attractor and intermittency in particle collisions

International Nuclear Information System (INIS)

Batunin, A.V.

1992-01-01

The hypothesis is proposed that the Feigenbaum attractor arising as a limit set in an infinite pichfork bifurcation sequence for unimodal one-dimensional maps underlies the intermittency phenomena in particle collisions. 23 refs.; 8 figs

Circuit implementation and multiform intermittency in a hyper-chaotic model extended from the Lorenz system

International Nuclear Information System (INIS)

Shi-Jian, Cang; Zeng-Qiang, Chen; Wen-Juan, Wu

2009-01-01

This paper presents a non-autonomous hyper-chaotic system, which is formed by adding a periodic driving signal to a four-dimensional chaotic model extended from the Lorenz system. The resulting non-autonomous hyper-chaotic system can display any dynamic behaviour among the periodic orbits, intermittency, chaos and hyper-chaos by controlling the frequency of the periodic signal. The phenomenon has been well demonstrated by numerical simulations, bifurcation analysis and electronic circuit realization. Moreover, the system is concrete evidence for the presence of Pomeau–Manneville Type-I intermittency and crisis-induced intermittency. The emergence of a different type of intermittency is similarly subjected to the frequency of periodic forcing. By statistical analysis, power scaling laws consisting in different intermittency are obtained for the lifetime in the laminar state between burst states

Optimally Stopped Optimization

Science.gov (United States)

Vinci, Walter; Lidar, Daniel

We combine the fields of heuristic optimization and optimal stopping. We propose a strategy for benchmarking randomized optimization algorithms that minimizes the expected total cost for obtaining a good solution with an optimal number of calls to the solver. To do so, rather than letting the objective function alone define a cost to be minimized, we introduce a further cost-per-call of the algorithm. We show that this problem can be formulated using optimal stopping theory. The expected cost is a flexible figure of merit for benchmarking probabilistic solvers that can be computed when the optimal solution is not known, and that avoids the biases and arbitrariness that affect other measures. The optimal stopping formulation of benchmarking directly leads to a real-time, optimal-utilization strategy for probabilistic optimizers with practical impact. We apply our formulation to benchmark the performance of a D-Wave 2X quantum annealer and the HFS solver, a specialized classical heuristic algorithm designed for low tree-width graphs. On a set of frustrated-loop instances with planted solutions defined on up to N = 1098 variables, the D-Wave device is between one to two orders of magnitude faster than the HFS solver.

Intermittent Auscultation for Intrapartum Fetal Heart Rate Surveillance: American College of Nurse-Midwives.

Science.gov (United States)

2015-01-01

Fetal heart rate surveillance is a standard component of intrapartum care. The fetal heart rate can be evaluated using intermittent auscultation or electronic fetal monitoring. Research that has compared these 2 strategies found them to be equivalent with respect to long-term neonatal outcomes. The purpose of this clinical bulletin by the American College of Nurse-Midwives is to review the evidence for use of intermittent auscultation and provide recommendations for intermittent auscultation technique, interpretation, and documentation. © 2015 by the American College of Nurse-Midwives.

Hovering and intermittent flight in birds

International Nuclear Information System (INIS)

Tobalske, Bret W

2010-01-01

Two styles of bird locomotion, hovering and intermittent flight, have great potential to inform future development of autonomous flying vehicles. Hummingbirds are the smallest flying vertebrates, and they are the only birds that can sustain hovering. Their ability to hover is due to their small size, high wingbeat frequency, relatively large margin of mass-specific power available for flight and a suite of anatomical features that include proportionally massive major flight muscles (pectoralis and supracoracoideus) and wing anatomy that enables them to leave their wings extended yet turned over (supinated) during upstroke so that they can generate lift to support their weight. Hummingbirds generate three times more lift during downstroke compared with upstroke, with the disparity due to wing twist during upstroke. Much like insects, hummingbirds exploit unsteady mechanisms during hovering including delayed stall during wing translation that is manifest as a leading-edge vortex (LEV) on the wing and rotational circulation at the end of each half stroke. Intermittent flight is common in small- and medium-sized birds and consists of pauses during which the wings are flexed (bound) or extended (glide). Flap-bounding appears to be an energy-saving style when flying relatively fast, with the production of lift by the body and tail critical to this saving. Flap-gliding is thought to be less costly than continuous flapping during flight at most speeds. Some species are known to shift from flap-gliding at slow speeds to flap-bounding at fast speeds, but there is an upper size limit for the ability to bound (∼0.3 kg) and small birds with rounded wings do not use intermittent glides.

Hovering and intermittent flight in birds

Energy Technology Data Exchange (ETDEWEB)

Tobalske, Bret W, E-mail: bret.tobalske@mso.umt.ed [Field Research Station at Fort Missoula, Division of Biological Sciences, University of Montana, Missoula, MT 59812 (United States)

2010-12-15

Two styles of bird locomotion, hovering and intermittent flight, have great potential to inform future development of autonomous flying vehicles. Hummingbirds are the smallest flying vertebrates, and they are the only birds that can sustain hovering. Their ability to hover is due to their small size, high wingbeat frequency, relatively large margin of mass-specific power available for flight and a suite of anatomical features that include proportionally massive major flight muscles (pectoralis and supracoracoideus) and wing anatomy that enables them to leave their wings extended yet turned over (supinated) during upstroke so that they can generate lift to support their weight. Hummingbirds generate three times more lift during downstroke compared with upstroke, with the disparity due to wing twist during upstroke. Much like insects, hummingbirds exploit unsteady mechanisms during hovering including delayed stall during wing translation that is manifest as a leading-edge vortex (LEV) on the wing and rotational circulation at the end of each half stroke. Intermittent flight is common in small- and medium-sized birds and consists of pauses during which the wings are flexed (bound) or extended (glide). Flap-bounding appears to be an energy-saving style when flying relatively fast, with the production of lift by the body and tail critical to this saving. Flap-gliding is thought to be less costly than continuous flapping during flight at most speeds. Some species are known to shift from flap-gliding at slow speeds to flap-bounding at fast speeds, but there is an upper size limit for the ability to bound ({approx}0.3 kg) and small birds with rounded wings do not use intermittent glides.

Effects of High-Intensity Intermittent Training on Vascular Function in Obese Preadolescent Boys.

Science.gov (United States)

Chuensiri, Napasakorn; Suksom, Daroonwan; Tanaka, Hirofumi

2018-01-01

High-intensity intermittent training (HIIT) may serve as an effective alternative to traditional endurance training, since HIIT has been shown to induce greater improvements in aerobic fitness and health-related markers in adult populations. Our objective was to determine whether HIIT and supramaximal high-intensity intermittent training (supra-HIIT) would improve vascular structure and function in obese preadolescent boys. Before the baseline testing, 48 obese preadolescent boys, aged 8-12 years, were randomly assigned into control (CON; n = 16), HIIT (8 × 2 minutes at 90% peak power output, n = 16), and supra-HIIT (8 × 20 seconds at 170% peak power output, n = 16) groups. Both exercise groups performed exercises on a cycle ergometer three times/week for 12 weeks. After 12 weeks, both HIIT and supra-HIIT did not affect body mass, body fat percentage, and waist circumference. Peak oxygen consumption (VO 2 peak) increased in both HIIT and supra-HIIT groups (p HIIT and supra-HIIT groups had higher resting metabolic rate than the control group (p HIIT and supra-HIIT program (all p HIIT and supra-HIIT groups (all p HIIT and supra-HIIT have favorable effects on aerobic capacity, metabolic rate, vascular function and structure, and blood lipid profile in obese preadolescent boys. HIIT may be a time efficient and effective exercise for preventing future cardiovascular disease in obese children.

Intermittent fasting during Ramadan: does it affect sleep?

Science.gov (United States)

Bahammam, Ahmed S; Almushailhi, Khalid; Pandi-Perumal, Seithikurippu R; Sharif, Munir M

2014-02-01

Islamic intermittent fasting is distinct from regular voluntary or experimental fasting. We hypothesised that if a regimen of a fixed sleep-wake schedule and a fixed caloric intake is followed during intermittent fasting, the effects of fasting on sleep architecture and daytime sleepiness will be minimal. Therefore, we designed this study to objectively assess the effects of Islamic intermittent fasting on sleep architecture and daytime sleepiness. Eight healthy volunteers reported to the Sleep Disorders Centre on five occasions for polysomnography and multiple sleep latency tests: (1) during adaptation; (2) 3 weeks before Ramadan, after having performed Islamic fasting for 1 week (baseline fasting); (3) 1 week before Ramadan (non-fasting baseline); (4) 2 weeks into Ramadan (Ramadan); and (5) 2 weeks after Ramadan (non-fasting; Recovery). Daytime sleepiness was assessed using the Epworth Sleepiness Scale and the multiple sleep latency test. The participants had a mean age of 26.6 ± 4.9 years, a body mass index of 23.7 ± 3.5 kg m(-2) and an Epworth Sleepiness Scale score of 7.3 ± 2.7. There was no change in weight or the Epworth Sleepiness Scale in the four study periods. The rapid eye movement sleep percentage was significantly lower during fasting. There was no difference in sleep latency, non-rapid eye movement sleep percentage, arousal index and sleep efficiency. The multiple sleep latency test analysis revealed no difference in the sleep latency between the 'non-fasting baseline', 'baseline fasting', 'Ramadan' and 'Recovery' time points. Under conditions of a fixed sleep-wake schedule and a fixed caloric intake, Islamic intermittent fasting results in decreased rapid eye movement sleep with no impact on other sleep stages, the arousal index or daytime sleepiness. © 2013 European Sleep Research Society.

The BUMP model of response planning: intermittent predictive control accounts for 10 Hz physiological tremor.

Science.gov (United States)

Bye, Robin T; Neilson, Peter D

2010-10-01

Physiological tremor during movement is characterized by ∼10 Hz oscillation observed both in the electromyogram activity and in the velocity profile. We propose that this particular rhythm occurs as the direct consequence of a movement response planning system that acts as an intermittent predictive controller operating at discrete intervals of ∼100 ms. The BUMP model of response planning describes such a system. It forms the kernel of Adaptive Model Theory which defines, in computational terms, a basic unit of motor production or BUMP. Each BUMP consists of three processes: (1) analyzing sensory information, (2) planning a desired optimal response, and (3) execution of that response. These processes operate in parallel across successive sequential BUMPs. The response planning process requires a discrete-time interval in which to generate a minimum acceleration trajectory to connect the actual response with the predicted future state of the target and compensate for executional error. We have shown previously that a response planning time of 100 ms accounts for the intermittency observed experimentally in visual tracking studies and for the psychological refractory period observed in double stimulation reaction time studies. We have also shown that simulations of aimed movement, using this same planning interval, reproduce experimentally observed speed-accuracy tradeoffs and movement velocity profiles. Here we show, by means of a simulation study of constant velocity tracking movements, that employing a 100 ms planning interval closely reproduces the measurement discontinuities and power spectra of electromyograms, joint-angles, and angular velocities of physiological tremor reported experimentally. We conclude that intermittent predictive control through sequential operation of BUMPs is a fundamental mechanism of 10 Hz physiological tremor in movement. Copyright © 2010 Elsevier B.V. All rights reserved.

Aging Cost Optimization for Planning and Management of Energy Storage Systems

Directory of Open Access Journals (Sweden)

Saman Korjani

2017-11-01

Full Text Available In recent years, many studies have proposed the use of energy storage systems (ESSs for the mitigation of renewable energy source (RES intermittent power output. However, the correct estimation of the ESS degradation costs is still an open issue, due to the difficult estimation of their aging in the presence of intermittent power inputs. This is particularly true for battery ESSs (BESSs, which have been proven to exhibit complex aging functions. Unfortunately, this collides with considering aging costs when performing ESS planning and management procedures, which are crucial for the exploitation of this technology. In order to overcome this issue, this paper presents the genetic algorithm-based multi-period optimal power flow (GA-MPOPF procedure, which aims to economically optimize the management of ESSs by taking into account their degradation costs. The proposed methodology has been tested in two different applications: the planning of the correct positioning of a Li-ion BESS in the PG& E 69 bus network in the presence of high RES penetration, and the definition of its management strategy. Simulation results show that GA-MPOPF is able to optimize the ESS usage for time scales of up to one month, even for complex operative costs functions, showing at the same time excellent convergence properties.

The influence of continuous and intermittent traffic noise on sleep

Science.gov (United States)

Eberhardt, J. L.; Stråle, L.-O.; Berlin, M. H.

1987-08-01

The effects of road traffic noise on sleep were studied in the laboratory using nine young male adults (aged 20-26). The subjects were exposed to noise with different temporal characteristics: (i) continuous traffic noise of 36 dB(A) or 45 dB(A), (ii) intermittent noise of 50 truck passages with L pmax = 45 dB(A) ( L eq = 29 dB(A)) or L pmax = 55 dB(A) ( L eq = 36 dB(A)), and (iii) a combination of continuous (45 dB(A)) and intermittent ( L pmax = 55 dB(A)) traffic noise. For one noise condition (intermittent 55 dB(A)) the effect of the use of ear plugs was also studied. The intermittent noise of L pmax = 45 dB(A) caused transitions towards lighter sleep, whereas 55 dB(A) was needed to induce awakening effects. It could be shown that the probability for arousal reactions depends on the emergence of the noise peaks from the background, rather than the absolute noise peak level. Continuous traffic noise of 45 dB(A) caused REM sleep deficits, while intermittent traffic noise of L pmax = 45 dB(A) caused stage III+IV deficits. The night with ear plugs was virtually undisturbed. After nights with REM sleep deficits the subjective sleep quality was rated lower and mood was influenced adversely. For the types of exposure used in the present investigation L eq alone is not an adequate descriptor of the noise dose, relating to the sleep disturbances observed. From the present experiment, together with other existing data, it might be concluded that the WHO recommendation of L eq = 35 dB(A) is adequate, but should be supplemented with a maximum noise level, as expressed for example in L pmax or LI, that should not be exceeded.

Portfolio optimization and the random magnet problem

Science.gov (United States)

Rosenow, B.; Plerou, V.; Gopikrishnan, P.; Stanley, H. E.

2002-08-01

Diversification of an investment into independently fluctuating assets reduces its risk. In reality, movements of assets are mutually correlated and therefore knowledge of cross-correlations among asset price movements are of great importance. Our results support the possibility that the problem of finding an investment in stocks which exposes invested funds to a minimum level of risk is analogous to the problem of finding the magnetization of a random magnet. The interactions for this "random magnet problem" are given by the cross-correlation matrix C of stock returns. We find that random matrix theory allows us to make an estimate for C which outperforms the standard estimate in terms of constructing an investment which carries a minimum level of risk.

Effects of chronic pollution and water flow intermittency on stream biofilms biodegradation capacity.

Science.gov (United States)

Rožman, Marko; Acuña, Vicenç; Petrović, Mira

2018-02-01

A mesocosm case study was conducted to gain understanding and practical knowledge on biofilm emerging contaminants biodegradation capacity under stressor and multiple stressor conditions. Two real life scenarios: I) biodegradation in a pristine intermittent stream experiencing acute pollution and II) biodegradation in a chronically polluted intermittent stream, were examined via a multifactorial experiment using an artificial stream facility. Stream biofilms were exposed to different water flow conditions i.e. permanent and intermittent water flow. Venlafaxine, a readily biodegradable pharmaceutical was used as a measure of biodegradation capacity while pollution was simulated by a mixture of four emerging contaminants (erythromycin, sulfisoxazole, diclofenac and imidacloprid in addition to venlafaxine) in environmentally relevant concentrations. Biodegradation kinetics monitored via LC-MS/MS was established, statistically evaluated, and used to link biodegradation with stress events. The results suggest that the effects of intermittent flow do not hinder and may even stimulate pristine biofilm biodegradation capacity. Chronic pollution completely reduced biodegradation in permanent water flow experimental treatments while no change in intermittent streams was observed. A combined effect of water flow conditions and emerging contaminants exposure on biodegradation was found. The decrease in biodegradation due to exposure to emerging contaminants is significantly greater in streams with permanent water flow suggesting that the short and medium term biodegradation capacity in intermittent systems may be preserved or even greater than in perennial streams. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of intermittent feedback control on robustness of human-like postural control system

Science.gov (United States)

Tanabe, Hiroko; Fujii, Keisuke; Suzuki, Yasuyuki; Kouzaki, Motoki

2016-03-01

Humans have to acquire postural robustness to maintain stability against internal and external perturbations. Human standing has been recently modelled using an intermittent feedback control. However, the causality inside of the closed-loop postural control system associated with the neural control strategy is still unknown. Here, we examined the effect of intermittent feedback control on postural robustness and of changes in active/passive components on joint coordinative structure. We implemented computer simulation of a quadruple inverted pendulum that is mechanically close to human tiptoe standing. We simulated three pairs of joint viscoelasticity and three choices of neural control strategies for each joint: intermittent, continuous, or passive control. We examined postural robustness for each parameter set by analysing the region of active feedback gain. We found intermittent control at the hip joint was necessary for model stabilisation and model parameters affected the robustness of the pendulum. Joint sways of the pendulum model were partially smaller than or similar to those of experimental data. In conclusion, intermittent feedback control was necessary for the stabilisation of the quadruple inverted pendulum. Also, postural robustness of human-like multi-link standing would be achieved by both passive joint viscoelasticity and neural joint control strategies.

Knockdown of angiopoietin-like 2 mimics the benefits of intermittent fasting on insulin responsiveness and weight loss.

Science.gov (United States)

Martel, Cécile; Pinçon, Anthony; Bélanger, Alexandre Maxime; Luo, Xiaoyan; Gillis, Marc-Antoine; de Montgolfier, Olivia; Thorin-Trescases, Nathalie; Thorin, Éric

2018-01-01

Angiopoietin-like 2 (ANGPTL2) is an inflammatory adipokine linking obesity to insulin resistance. Intermittent fasting, on the other hand, is a lifestyle intervention able to prevent obesity and diabetes but difficult to implement and maintain. Our objectives were to characterize a link between ANGPTL2 and intermittent fasting and to investigate whether the knockdown of ANGPTL2 reproduces the benefits of intermittent fasting on weight gain and insulin responsiveness in knockdown and wild-type littermates mice. Intermittent fasting, access to food ad libitum once every other day, was initiated at the age of three months and maintained for four months. Intermittent fasting decreased by 63% (p < 0.05) gene expression of angptl2 in adipose tissue of wild-type mice. As expected, intermittent fasting improved insulin sensitivity (p < 0.05) and limited weight gain (p < 0.05) in wild-type mice. Knockdown mice fed ad libitum, however, were comparable to wild-type mice following the intermittent fasting regimen: insulin sensitivity and weight gain were identical, while intermittent fasting had no additional impact on these parameters in knockdown mice. Energy intake was similar between both wild-type fed intermittent fasting and ANGPTL2 knockdown mice fed ad libitum, suggesting that intermittent fasting and knockdown of ANGPTL2 equally lower feeding efficiency. These results suggest that the reduction of ANGPTL2 could be a useful and promising strategy to prevent obesity and insulin resistance, although further investigation of the mechanisms linking ANGPTL2 and intermittent fasting is warranted. Impact statement Intermittent fasting is an efficient diet pattern to prevent weight gain and improve insulin sensitivity. It is, however, a difficult regimen to follow and compliance is expected to be very low. In this work, we demonstrate that knockdown of ANGPTL2 in mice fed ad libitum mimics the beneficial effects of intermittent fasting on weight gain and insulin

High intensity aerobic exercise training improves chronic intermittent hypoxia-induced insulin resistance without basal autophagy modulation.

Science.gov (United States)

Pauly, Marion; Assense, Allan; Rondon, Aurélie; Thomas, Amandine; Dubouchaud, Hervé; Freyssenet, Damien; Benoit, Henri; Castells, Josiane; Flore, Patrice

2017-03-03

Chronic intermittent hypoxia (IH) associated with obstructive sleep apnea (OSA) is a major risk factor for cardiovascular and metabolic diseases (insulin resistance: IR). Autophagy is involved in the pathophysiology of IR and high intensity training (HIT) has recently emerged as a potential therapy. We aimed to confirm IH-induced IR in a tissue-dependent way and to explore the preventive effect of HIT on IR-induced by IH. Thirty Swiss 129 male mice were randomly assigned to Normoxia (N), Intermittent Hypoxia (IH: 21-5% FiO 2 , 30 s cycle, 8 h/day) or IH associated with high intensity training (IH HIT). After 8 days of HIT (2*24 min, 50 to 90% of Maximal Aerobic Speed or MAS on a treadmill) mice underwent 14 days IH or N. We found that IH induced IR, characterized by a greater glycemia, an impaired insulin sensitivity and lower AKT phosphorylation in adipose tissue and liver. Nevertheless, MAS and AKT phosphorylation were greater in muscle after IH. IH associated with HIT induced better systemic insulin sensitivity and AKT phosphorylation in liver. Autophagy markers were not altered in both conditions. These findings suggest that HIT could represent a preventive strategy to limit IH-induced IR without change of basal autophagy.

Intermittent character of interplanetary magnetic field fluctuations

International Nuclear Information System (INIS)

Bruno, Roberto; Carbone, Vincenzo; Chapman, Sandra; Hnat, Bogdan; Noullez, Alain; Sorriso-Valvo, Luca

2007-01-01

Interplanetary magnetic field magnitude fluctuations are notoriously more intermittent than velocity fluctuations in both fast and slow wind. This behavior has been interpreted in terms of the anomalous scaling observed in passive scalars in fully developed hydrodynamic turbulence. In this paper, the strong intermittent nature of the interplanetary magnetic field is briefly discussed comparing results performed during different phases of the solar cycle. The scaling properties of the interplanetary magnetic field magnitude show solar cycle variation that can be distinguished in the scaling exponents revealed by structure functions. The scaling exponents observed around the solar maximum coincide, within the errors, to those measured for passive scalars in hydrodynamic turbulence. However, it is also found that the values are not universal in the sense that the solar cycle variation may be reflected in dependence on the structure of the velocity field

Obstructive sleep apnea: role of intermittent hypoxia and inflammation.

Science.gov (United States)

May, Anna M; Mehra, Reena

2014-10-01

Obstructive sleep apnea results in intermittent hypoxia via repetitive upper airway obstruction leading to partial or complete upper airway closure, apneas and hypopneas, respectively. Intermittent hypoxia leads to sympathetic nervous system activation and oxidative stress with a resultant systemic inflammatory cascade. The putative mechanism by which obstructive sleep apnea has been linked to numerous pathologic conditions including stoke, cardiovascular disease, hypertension, and metabolic derangements is through these systemic effects. Treatment of obstructive sleep apnea appears to reduce systemic markers of inflammation and ameliorates the adverse sequelae of this disease. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Potential Benefits and Harms of Intermittent Energy Restriction and Intermittent Fasting Amongst Obese, Overweight and Normal Weight Subjects—A Narrative Review of Human and Animal Evidence

Directory of Open Access Journals (Sweden)

Michelle Harvie

2017-01-01

Full Text Available Intermittent energy restriction (IER has become popular as a means of weight control amongst people who are overweight and obese, and is also undertaken by normal weight people hoping spells of marked energy restriction will optimise their health. This review summarises randomised comparisons of intermittent and isoenergetic continuous energy restriction for weight loss to manage overweight and obesity. It also summarises the potential beneficial or adverse effects of IER on body composition, adipose stores and metabolic effects from human studies, including studies amongst normal weight subjects and relevant animal experimentation. Six small short term (<6 month studies amongst overweight or obese individuals indicate that intermittent energy restriction is equal to continuous restriction for weight loss, with one study reporting greater reductions in body fat, and two studies reporting greater reductions in HOMA insulin resistance in response to IER, with no obvious evidence of harm. Studies amongst normal weight subjects and different animal models highlight the potential beneficial and adverse effects of intermittent compared to continuous energy restriction on ectopic and visceral fat stores, adipocyte size, insulin resistance, and metabolic flexibility. The longer term benefits or harms of IER amongst people who are overweight or obese, and particularly amongst normal weight subjects, is not known and is a priority for further investigation.

Potential Benefits and Harms of Intermittent Energy Restriction and Intermittent Fasting Amongst Obese, Overweight and Normal Weight Subjects-A Narrative Review of Human and Animal Evidence.

Science.gov (United States)

Harvie, Michelle; Howell, Anthony

2017-01-19

Intermittent energy restriction (IER) has become popular as a means of weight control amongst people who are overweight and obese, and is also undertaken by normal weight people hoping spells of marked energy restriction will optimise their health. This review summarises randomised comparisons of intermittent and isoenergetic continuous energy restriction for weight loss to manage overweight and obesity. It also summarises the potential beneficial or adverse effects of IER on body composition, adipose stores and metabolic effects from human studies, including studies amongst normal weight subjects and relevant animal experimentation. Six small short term (<6 month) studies amongst overweight or obese individuals indicate that intermittent energy restriction is equal to continuous restriction for weight loss, with one study reporting greater reductions in body fat, and two studies reporting greater reductions in HOMA insulin resistance in response to IER, with no obvious evidence of harm. Studies amongst normal weight subjects and different animal models highlight the potential beneficial and adverse effects of intermittent compared to continuous energy restriction on ectopic and visceral fat stores, adipocyte size, insulin resistance, and metabolic flexibility. The longer term benefits or harms of IER amongst people who are overweight or obese, and particularly amongst normal weight subjects, is not known and is a priority for further investigation.

Potential Benefits and Harms of Intermittent Energy Restriction and Intermittent Fasting Amongst Obese, Overweight and Normal Weight Subjects—A Narrative Review of Human and Animal Evidence

Science.gov (United States)

Harvie, Michelle; Howell, Anthony

2017-01-01

Intermittent energy restriction (IER) has become popular as a means of weight control amongst people who are overweight and obese, and is also undertaken by normal weight people hoping spells of marked energy restriction will optimise their health. This review summarises randomised comparisons of intermittent and isoenergetic continuous energy restriction for weight loss to manage overweight and obesity. It also summarises the potential beneficial or adverse effects of IER on body composition, adipose stores and metabolic effects from human studies, including studies amongst normal weight subjects and relevant animal experimentation. Six small short term (obese individuals indicate that intermittent energy restriction is equal to continuous restriction for weight loss, with one study reporting greater reductions in body fat, and two studies reporting greater reductions in HOMA insulin resistance in response to IER, with no obvious evidence of harm. Studies amongst normal weight subjects and different animal models highlight the potential beneficial and adverse effects of intermittent compared to continuous energy restriction on ectopic and visceral fat stores, adipocyte size, insulin resistance, and metabolic flexibility. The longer term benefits or harms of IER amongst people who are overweight or obese, and particularly amongst normal weight subjects, is not known and is a priority for further investigation. PMID:28106818

Composeable Chat over Low-Bandwidth Intermittent Communication Links

National Research Council Canada - National Science Library

Wilcox, D. R

2007-01-01

Intermittent low-bandwidth communication environments, such as those encountered in U.S. Navy tactical radio and satellite links, have special requirements that do not pertain to commercial applications...

Impact of continuous and intermittent supply of electric field on the function and microbial community of wastewater treatment electro-bioreactors

International Nuclear Information System (INIS)

Zeyoudi, Mozah; Altenaiji, Eiman; Ozer, Lutfiye Y.; Ahmed, Iftikhar; Yousef, Ahmed F.; Hasan, Shadi W.

2015-01-01

The application of electro-technologies to existing biological treatment methods in the United Arab Emirates (UAE) requires further understanding of how microorganisms respond to said electro-technologies. This is necessary in order to optimize and enhance the treated effluent water's quality. Therefore, the primary objective of this research study was to evaluate the microbial communities present in a bio-electrochemical reactor under different operating conditions where variables such as current density and exposure time to electric field were modified in order to achieve system process stability. This study was divided into three Phases. In Phase 1, a laboratory scale study was conducted at different current densities ranging between 5 and 20 A m −2 continuously supplied with no addition of substrate. In Phase 2, a laboratory scale study was conducted at continuous supply of electric field at different current densities ranging between 5 and 20 A m −2 (Stage 1), and at intermittent supply of electric field at constant current density of 15 A m −2 (Stage 2). In each Phase, biokinetics (bacterial counts, growth rates and doubling times), and substrate utilization rate (organic removal) were assessed. Overall, results showed that continuous and intermittent supply of electric field significantly increased observed bacterial counts, growth rates, and soluble chemical oxygen demand (sCOD) removal at lower current densities. High resolution melting analysis (HRM) from Phase 3 indicated that intermittent supply of electric field caused a shift in the microbial population structure in a wastewater bioreactor, while no shift in microbial community population structure was observed in reactors supplied with constant current densities. Taken together, the results presented here indicate that introducing low intermittent or constant electrical current densities to existing biological treatment methods in the UAE has the potential to lead to more efficient and

Beneficial Effects of New Zealand Blackcurrant Extract on Maximal Sprint Speed during the Loughborough Intermittent Shuttle Test

Directory of Open Access Journals (Sweden)

Mark ET Willems

2016-08-01

Full Text Available New Zealand blackcurrant (NZBC extract has been shown to enhance high-intensity intermittent treadmill running. We examined the effects of NZBC extract during the Loughborough Intermittent Shuttle Test (LIST which involves 5 × 15 min blocks with intermittent 15-m maximal sprints, interspersed by moderate and high-intensity running to simulate team sport activity, and a subsequent run to exhaustion. Thirteen males (age: 22 ± 1 year, V ˙ O 2 max : 50 ± 5 mL·kg−1·min−1 participated in three indoor sessions (T: 24 ± 3 °C, humidity: 52% ± 9%. In the first session, a multistage fitness test was completed to determine peak running speed and estimate V ˙ O 2 max . Participants consumed NZBC extract in capsules (300 mg·day−1 CurraNZ™ or placebo (PL (300 mg·day−1 microcrystalline cellulose M102 for seven days in a double-blind, randomized, cross-over design (wash-out at least seven days. NZBC extract did not affect average 15-m sprint times in each block. NZBC reduced slowing of the fastest sprint between block 1 and 5 (PL: 0.12 ± 0.07 s; NZBC: 0.06 ± 0.12 s; p < 0.05. NZBC extract had no effect on heart rate, vertical jump power, lactate and time to exhaustion (PL: 13.44 ± 8.09 min, NZBC: 15.78 ± 9.40 min, p > 0.05. However, eight participants had higher running times to exhaustion when consuming NZBC extract. New Zealand blackcurrant extract may enhance performance in team sports with repeated maximal sprints.

Study of intermittent bifurcations and chaos in boost PFC converters by nonlinear discrete models

International Nuclear Information System (INIS)

Zhang Hao; Ma Xikui; Xue Bianling; Liu Weizeng

2005-01-01

This paper mainly deals with nonlinear phenomena like intermittent bifurcations and chaos in boost PFC converters under peak-current control mode. Two nonlinear models in the form of discrete maps are derived to describe precisely the nonlinear dynamics of boost PFC converters from two points of view, i.e., low- and high-frequency regimes. Based on the presented discrete models, both the evolution of intermittent behavior and the periodicity of intermittency are investigated in detail from the fast and slow-scale aspects, respectively. Numerical results show that the occurrence of intermittent bifurcations and chaos with half one line period is one of the most distinguished dynamical characteristics. Finally, we make some instructive conclusions, which prove to be helpful in improving the performances of practical circuits

Synchronization of Hierarchical Time-Varying Neural Networks Based on Asynchronous and Intermittent Sampled-Data Control.

Science.gov (United States)

Xiong, Wenjun; Patel, Ragini; Cao, Jinde; Zheng, Wei Xing

In this brief, our purpose is to apply asynchronous and intermittent sampled-data control methods to achieve the synchronization of hierarchical time-varying neural networks. The asynchronous and intermittent sampled-data controllers are proposed for two reasons: 1) the controllers may not transmit the control information simultaneously and 2) the controllers cannot always exist at any time . The synchronization is then discussed for a kind of hierarchical time-varying neural networks based on the asynchronous and intermittent sampled-data controllers. Finally, the simulation results are given to illustrate the usefulness of the developed criteria.In this brief, our purpose is to apply asynchronous and intermittent sampled-data control methods to achieve the synchronization of hierarchical time-varying neural networks. The asynchronous and intermittent sampled-data controllers are proposed for two reasons: 1) the controllers may not transmit the control information simultaneously and 2) the controllers cannot always exist at any time . The synchronization is then discussed for a kind of hierarchical time-varying neural networks based on the asynchronous and intermittent sampled-data controllers. Finally, the simulation results are given to illustrate the usefulness of the developed criteria.

Potential Benefits and Harms of Intermittent Energy Restriction and Intermittent Fasting Amongst Obese, Overweight and Normal Weight Subjects—A Narrative Review of Human and Animal Evidence

OpenAIRE

Howell, Anthony; Harvie, Michelle

2017-01-01

Intermittent energy restriction (IER) has become popular as a means of weight control amongst people who are overweight and obese, and is also undertaken by normal weight people hoping spells of marked energy restriction will optimise their health. This review summarises randomised comparisons of intermittent and isoenergetic continuous energy restriction for weight loss to manage overweight and obesity. It also summarises the potential beneficial or adverse effects of IER on body composition...

Intermittent preventive treatment of malaria in pregnancy

DEFF Research Database (Denmark)

Mbonye, A.K.; Hansen, Kristian Schultz; Bygbjerg, Ib Christian

2008-01-01

The main objective of this study was to assess whether traditional birth attendants, drug-shop vendors, community reproductive health workers and adolescent peer mobilisers could administer intermittent preventive treatment (IPTp) with sulfadoxine-pyrimethamine (SP) to pregnant women. The study w...

Investigation of intermittency in simulated and experimental turbulence data by wavelet analysis

International Nuclear Information System (INIS)

Mahdizadeh, N.; Ramisch, M.; Stroth, U.; Lechte, C.; Scott, B.D.

2004-01-01

Turbulent transport in magnetized plasmas has an intermittent nature. Peaked probability density functions and a 1/frequency decay of the power spectra have been interpreted as signs of self-organized criticality generated, similar to a sand pile, by the critical gradients of ion- (ITG) or electron-temperature-gradient (ETG) driven instabilities. In order to investigate the degree of intermittency in toroidally confined plasmas in the absence of critical pressure or temperature gradients, data from the drift-Alfven-wave turbulence code DALF3 [B. Scott, Plasma Phys. Controlled Fusion 39, 1635 (1997)], running with a fixed background pressure gradient, and from a weakly driven low-temperature plasma are analyzed. The intermittency is studied on different temporal scales, which are separated by a wavelet transform. Simulated and experimental data reproduce the results on intermittent transport found in fusion plasmas. It can therefore be expected that in fusion plasmas, too, a substantial fraction of the bursty nature of turbulent transport is not related to avalanches caused by a critical gradient as generated by ITG or ETG turbulence

Capacity Optimization of Renewable Energy Sources and Battery Storage in an Autonomous Telecommunication Facility

DEFF Research Database (Denmark)

Dragicevic, Tomislav; Pandžić, Hrvoje; Škrlec, Davor

2014-01-01

This paper describes a robust optimization approach to minimize the total cost of supplying a remote telecommunication station exclusively by renewable energy sources (RES). Due to the intermittent nature of RES, such as photovoltaic (PV) panels and small wind turbines, they are normally supported...... by a central energy storage system (ESS), consisting of a battery and a fuel cell. The optimization is carried out as a robust mixed-integer linear program (RMILP), and results in different optimal solutions, depending on budgets of uncertainty, each of which yields different RES and storage capacities...

Mouse Intermittent Hypoxia Mimicking Apnea of Prematurity: Effects on Myelinogenesis and Axonal Maturation

Science.gov (United States)

CAI, JUN; TUONG, CHI MINH; ZHANG, YIPING; SHIELDS, CHRISTOPHER B.; GUO, GANG; FU, HUI; GOZAL, DAVID

2014-01-01

Premature babies are at high risk for both infantile apnea and long-term neurobehavioral deficits. Recent studies suggest that diffuse structural changes in brain white matter are a positive predictor of poor cognitive outcomes. Since oligodendrocyte maturation, myelination, axon development and synapse formation mainly occur in the 3rd trimester of gestation and 1st postnatal year, infantile apnea could lead to and/or exaggerate white matter impairments in preterm neonates. Therefore, we investigated oligodendroglia and axon development in a neonatal mouse model of intermittent hypoxia between postnatal days 2 to 10. During critical phases of central nervous system development, intermittent hypoxia induced hypomyelination in the corpus callosum, striatum, fornix and cerebellum, but not the pons or spinal cord. Intermittent hypoxia-elicited alterations in myelin-forming processes were reflected by decreased expression of myelin proteins, including MBP, PLP, MAG and CNPase, possibly due to arrested maturation of oligodendrocytes. Ultra-structural abnormalities were apparent in the myelin sheath and axon. Immature oligodendrocytes were more vulnerable to neonatal intermittent hypoxia exposures than developing axons, suggesting that hypomyelination may contribute, at least partially, to axonal deficits. Insufficient neurofilament synthesis with anomalous components of neurofilament subunits, β-tubulin and MAP2 isoforms indicated immaturity of axons in intermittent hypoxia-exposed mouse brains. In addition, down-regulation of Synapsin I, Synaptophysin and Gap-43 phosphorylation suggested a potential stunt in axonogenesis and synaptogenesis. The region-selective and complex impairment in brain white matter induced by intermittent hypoxia was further associated with electrophysiological changes that may underlie long-term neurobehavioral sequelae. PMID:21953180

Fractal structures and intermittency in QCD

International Nuclear Information System (INIS)

Gustafson, Goesta.

1990-04-01

New results are presented for fractal structures and intermittency in QCD parton showers. A geometrical interpretation of the anomalous dimension in QCD is given. It is shown that model predications for factorial moments in the PEP-PETRA energy range are increased. if the properties of directly produced pions are more carefully taken into account

The importance of active learning and practice on the students' mastery of pharmacokinetic calculations for the intermittent intravenous infusion dosing of antibiotics

Directory of Open Access Journals (Sweden)

Mehvar Reza

2012-11-01

Full Text Available Abstract Background Estimation of pharmacokinetic parameters after intermittent intravenous infusion (III of antibiotics, such as aminoglycosides or vancomycin, has traditionally been a difficult subject for students in clinical pharmacology or pharmacokinetic courses. Additionally, samples taken at different intervals during repeated dose therapy require manipulation of sampling times before accurate calculation of the patient-specific pharmacokinetic parameters. The main goal of this study was to evaluate the effectiveness of active learning tools and practice opportunities on the ability of students to estimate pharmacokinetic parameters from the plasma samples obtained at different intervals following intermittent intravenous infusion. Methods An extensive reading note, with examples, and a problem case, based on a patient’s chart data, were created and made available to students before the class session. Students were required to work through the case before attending the class. The class session was devoted to the discussion of the case requiring active participation of the students using a random participation program. After the class, students were given additional opportunities to practice the calculations, using online modules developed by the instructor, before submitting an online assignment. Results The performance of students significantly (P P  Conclusions Despite being a difficult subject, students achieve mastery of pharmacokinetic calculations for the topic of intermittent intravenous infusion when appropriate active learning strategies and practice opportunities are employed.

Effects of hydrogen rich water on prolonged intermittent exercise.

Science.gov (United States)

Da Ponte, Alessandro; Giovanelli, Nicola; Nigris, Daniele; Lazzer, Stefano

2018-05-01

Recent studies showed a positive effect of hydrogen rich water (HRW) intake on acid-base homeostasis at rest. We investigated 2-weeks of HRW intake on repeated sprint performance and acid-base status during prolonged intermittent cycling exercise. In a cross over single-blind protocol, 8 trained male cyclists (age [mean±SD] 41±7 years, body mass 72.3±4.4 kg, height 1.77±0.04 m, maximal oxygen uptake [V̇O2max] 52.6±4.4 mL·kg-1·min-1) were provided daily with 2 liters of placebo normal water (PLA, pH 7.6, oxidation/reduction potential [ORP] +230 mV, free hydrogen content 0 ppb) or HRW (pH 9.8, ORP -180 mV, free Hydrogen 450 ppb). Tests were performed at baseline and after each period of 2 weeks of treatment. The treatments were counter-balanced and the sequence randomized. The 30-minute intermittent cycling trial consisted in 10 3-minute blocks, each one composed by 90 seconds at 40% V̇O2max, 60 seconds at 60% V̇O2max, 16 seconds all out sprint, and 14 seconds active recovery. Oxygen uptake (V̇O2), heart rate and power output were measured during the whole test, while mean and peak power output (PPO), time to peak power and Fatigue Index (FI) were determined during all the 16 seconds sprints. Lactate, pH and bicarbonate (HCO3-) concentrations were determined at rest and after each sprint on blood obtained by an antecubital vein indwelling catheter. In the PLA group, PPO in absolute values decreased significantly at the 8th and 9th of 10 sprints and in relative values, ΔPPO, decreased significantly at 6th, 8th and 9th of 10 sprints (by mean: -12±5%, Pmay help to maintain PPO in repetitive sprints to exhaustion over 30 minutes.

Thermodynamics and structure of liquid metals from a consistent optimized random phase approximation

International Nuclear Information System (INIS)

Akinlade, O.; Badirkhan, Z.; Pastore, G.

2000-05-01

We study thermodynamics and structural properties of several liquid metals to assess the validity of the generalized non-local model potential (GNMP) of Li et. al. [J.Phys. F16,309 (1986)]. By using a new thermodynamically consistent version of the optimized random phase approximation (ORPA), especially adapted to continuous reference potentials, we improve our previous results obtained within the variational approach based on the Gibbs - Bogoliubov inequality. Hinging on the unified and very accurate evaluation of structure factors and thermodynamic quantities provided by the ORPA, we find that the GNMP yields satisfactory results for the alkali metals, however, those for the polyvalent metals point to a substantial inadequacy of the GNMP for high valence systems. (author)

Quasi optimal and adaptive sparse grids with control variates for PDEs with random diffusion coefficient

KAUST Repository

Tamellini, Lorenzo

2016-01-05

In this talk we discuss possible strategies to minimize the impact of the curse of dimensionality effect when building sparse-grid approximations of a multivariate function u = u(y1, ..., yN ). More precisely, we present a knapsack approach , in which we estimate the cost and the error reduction contribution of each possible component of the sparse grid, and then we choose the components with the highest error reduction /cost ratio. The estimates of the error reduction are obtained by either a mixed a-priori / a-posteriori approach, in which we first derive a theoretical bound and then tune it with some inexpensive auxiliary computations (resulting in the so-called quasi-optimal sparse grids ), or by a fully a-posteriori approach (obtaining the so-called adaptive sparse grids ). This framework is very general and can be used to build quasi-optimal/adaptive sparse grids on bounded and unbounded domains (e.g. u depending on uniform and normal random distributions for yn), using both nested and non-nested families of univariate collocation points. We present some theoretical convergence results as well as numerical results showing the efficiency of the proposed approach for the approximation of the solution of elliptic PDEs with random diffusion coefficients. In this context, to treat the case of rough permeability fields in which a sparse grid approach may not be suitable, we propose to use the sparse grids as a control variate in a Monte Carlo simulation.

The effects of acebutolol and metoprolol on walking distances and distal blood pressure in hypertensive patients with intermittent claudication

DEFF Research Database (Denmark)

Svendsen, T L; Jelnes, Rolf; Tønnesen, K H

1986-01-01

The effects of acebutolol (with intrinsic sympathomimetic activity (ISA] and metoprolol (without ISA) on arm blood pressure, ankle systolic blood pressure, claudication distances (CD) and maximal walking distances (MWD) were compared in patients with essential hypertension and intermittent...... claudication. Fourteen patients participated in a long-term, open, randomized cross-over study. After randomization the patients received either acebutolol, 200 mg b.i.d., or metoprolol, 100 mg b.i.d. After eight weeks the drugs were shifted and after another eight weeks they were withdrawn. Arm and ankle...... pressure there were no significant changes in ankle blood pressure, CD or MWD after the two drugs. After withdrawal of the drugs and after the arm blood pressure had returned to the control value no significant changes were seen in CD, MWD or ankle blood pressure. It is concluded that beta-blockers have...

Cardiovascular disease in obstructive sleep apnoea syndrome: the role of intermittent hypoxia and inflammation.

LENUS (Irish Health Repository)

Garvey, J F

2012-02-01

There is increasing evidence that intermittent hypoxia plays a role in the development of cardiovascular risk in obstructive sleep apnoea syndrome (OSAS) through the activation of inflammatory pathways. The development of translational models of intermittent hypoxia has allowed investigation of its role in the activation of inflammatory mechanisms and promotion of cardiovascular disease in OSAS. There are noticeable differences in the response to intermittent hypoxia between body tissues but the hypoxia-sensitive transcription factors hypoxia-inducible factor-1 and nuclear factor-kappaB appear to play a key role in mediating the inflammatory and cardiovascular consequences of OSAS. Expanding our understanding of these pathways, the cross-talk between them and the activation of inflammatory mechanisms by intermittent hypoxia in OSAS will provide new avenues of therapeutic opportunity for the disease.

Metabolic syndrome in patients with prostate cancer undergoing intermittent androgen-deprivation therapy.

Science.gov (United States)

Rezaei, Mohammadali Mohammadzadeh; Rezaei, Mohammadhadi Mohammadzadeh; Ghoreifi, Alireza; Kerigh, Behzad Feyzzadeh

2016-01-01

The presence of metabolic syndrome in men with prostate cancer (PCa) undergoing androgen-deprivation therapy (ADT), especially intermittent type, has not been completely evaluated. The aim of this study is to evaluate metabolic syndrome in men with PCa undergoing intermittent ADT. In this longitudinal study, we studied the prevalence of metabolic syndrome and its components in 190 patients who were undergoing intermittent ADT. The metabolic syndrome was defined according to the Adult Treatment Panel III criteria. All metabolic parameters, including lipid profile, blood glucose, blood pressures, and waist circumferences of the patients were measured six and 12 months after treatment. Mean age of the patients was 67.5 ± 6.74 years. The incidence of metabolic syndrome after six and 12 months was 6.8% and 14.7%, respectively. Analysis of various components of the metabolic syndrome revealed that patients had significantly higher overall prevalence of hyperglycemia, abdominal obesity, and hypertriglyceridemia in their six- and 12-month followups, but blood pressure has not been changed in the same period except for diastolic blood pressure after six months. Although there was an increased risk of metabolic syndrome in patients receiving intermittent ADT, it was lower than other studies that treated the same patients with continuous ADT. Also it seems that intermittent ADT has less metabolic complications than continuous ADT and could be used as a safe alternative in patients with advanced and metastatic PCa.

Coherent and intermittent ensemble oscillations emerge from networks of irregular spiking neurons.

Science.gov (United States)

Hoseini, Mahmood S; Wessel, Ralf

2016-01-01

Local field potential (LFP) recordings from spatially distant cortical circuits reveal episodes of coherent gamma oscillations that are intermittent, and of variable peak frequency and duration. Concurrently, single neuron spiking remains largely irregular and of low rate. The underlying potential mechanisms of this emergent network activity have long been debated. Here we reproduce such intermittent ensemble oscillations in a model network, consisting of excitatory and inhibitory model neurons with the characteristics of regular-spiking (RS) pyramidal neurons, and fast-spiking (FS) and low-threshold spiking (LTS) interneurons. We find that fluctuations in the external inputs trigger reciprocally connected and irregularly spiking RS and FS neurons in episodes of ensemble oscillations, which are terminated by the recruitment of the LTS population with concurrent accumulation of inhibitory conductance in both RS and FS neurons. The model qualitatively reproduces experimentally observed phase drift, oscillation episode duration distributions, variation in the peak frequency, and the concurrent irregular single-neuron spiking at low rate. Furthermore, consistent with previous experimental studies using optogenetic manipulation, periodic activation of FS, but not RS, model neurons causes enhancement of gamma oscillations. In addition, increasing the coupling between two model networks from low to high reveals a transition from independent intermittent oscillations to coherent intermittent oscillations. In conclusion, the model network suggests biologically plausible mechanisms for the generation of episodes of coherent intermittent ensemble oscillations with irregular spiking neurons in cortical circuits. Copyright © 2016 the American Physiological Society.

Intermittency exponent of the turbulent energy cascade

International Nuclear Information System (INIS)

Cleve, J.; Greiner, M.; Pearson, B.R.; Sreenivasan, K.R.

2006-12-01

We consider the turbulent energy dissipation from one-dimensional records in experiments using air and gaseous helium at cryogenic temperatures, and obtain the intermittency exponent via the two-point correlation function of the energy dissipation. The air data are obtained in a number of flows in a wind tunnel and the atmospheric boundary layer at a height of about 35 m above the ground. The helium data correspond to the centerline of a jet exhausting into a container. The air data on the intermittency exponent are consistent with each other and with a trend that increases with the Taylor microscale Reynolds number, R λ , of up to about 1000 and saturates thereafter. On the other hand, the helium data cluster around a constant value at nearly all R λ , this being about half of the asymptotic value for the air data. Some possible explanation is offered for this anomaly. (author)

Determining order-up-to levels under periodic review for compound binomial (intermittent) demand

NARCIS (Netherlands)

Teunter, R. H.; Syntetos, A. A.; Babai, M. Z.

2010-01-01

We propose a new method for determining order-up-to levels for intermittent demand items in a periodic review system. Contrary to existing methods, we exploit the intermittent character of demand by modelling lead time demand as a compound binomial process. in an extensive numerical study using

Does Vaping in E-Cigarette Advertisements Affect Tobacco Smoking Urge, Intentions, and Perceptions in Daily, Intermittent, and Former Smokers?

Science.gov (United States)

Maloney, Erin K; Cappella, Joseph N

2016-01-01

Visual depictions of vaping in electronic cigarette advertisements may serve as smoking cues to smokers and former smokers, increasing urge to smoke and smoking behavior, and decreasing self-efficacy, attitudes, and intentions to quit or abstain. After assessing baseline urge to smoke, 301 daily smokers, 272 intermittent smokers, and 311 former smokers were randomly assigned to view three e-cigarette commercials with vaping visuals (the cue condition) or without vaping visuals (the no-cue condition), or to answer unrelated media use questions (the no-ad condition). Participants then answered a posttest questionnaire assessing the outcome variables of interest. Relative to other conditions, in the cue condition, daily smokers reported greater urge to smoke a tobacco cigarette and a marginally significantly greater incidence of actually smoking a tobacco cigarette during the experiment. Former smokers in the cue condition reported lower intentions to abstain from smoking than former smokers in other conditions. No significant differences emerged among intermittent smokers across conditions. These data suggest that visual depictions of vaping in e-cigarette commercials increase daily smokers' urge to smoke cigarettes and may lead to more actual smoking behavior. For former smokers, these cues in advertising may undermine abstinence efforts. Intermittent smokers did not appear to be reactive to these cues. A lack of significant differences between participants in the no-cue and no-ad conditions compared to the cue condition suggests that visual depictions of e-cigarettes and vaping function as smoking cues, and cue reactivity is the mechanism through which these effects were obtained.

Intermittent fasting decreases oxidative stress parameters in Wistar rats (Rattus norvegicus)

OpenAIRE

Titis Nurmasitoh; Shindy Yudha Utami; Endah Kusumawardani; Abdulhalim Ahmad Najmuddin; Ika Fidianingsih

2018-01-01

Background Chronic and degenerative diseases are closely related to modern lifestyles that tend to be deficient in physical activity but excessive in food intake. One method used to overcome this problem is dietary restriction through intermittent fasting. Intermittent fasting decreases the risk of chronic and degenerative diseases, e.g. by lowering oxidative stress. Oxidative stress can be determined from the malondialdehyde (MDA) levels and lipid profile in the blood. The present study a...

Intermittent Intraoperative Neural Monitoring Technology in Minimally Invasive Video-Assisted Thyroidectomy: A Preliminary Study.