Science.gov

Sample records for diverse delayed effects

  1. Pectin enhances the effect of fecal microbiota transplantation in ulcerative colitis by delaying the loss of diversity of gut flora.

    PubMed

    Wei, Yao; Gong, Jianfeng; Zhu, Weiming; Tian, Hongliang; Ding, Chao; Gu, Lili; Li, Ning; Li, Jieshou

    2016-11-03

    Fecal microbiota transplantation (FMT) induces remission in ulcerative colitis (UC). However, the treatment effect of FMT diminishes over time. Maintaining the diversity of the gut flora for long periods may improve the effects of FMT in UC. Pectin, which can be fermented by gut microbiota into short-chain fatty acids, is postulated to shape the composition and maintain the balance of gut microbiota following transplantation. This study investigated whether pectin could enhance the effects of FMT in UC patients. Three FMT patients and four FMTP patients achieved the primary outcome. The Mayo scores of the FMTP group were lower than those of the FMT group at weeks 4 and 12 (P = 0.042 and P = 0.042, respectively). There were no differences in the diversity of the gut flora between the two groups at weeks 4 and 12; however, the composition of the gut flora of the FMTP group was more similar than the FMT group to that of the donor at all-time points post-treatment. Pectin decreased the Mayo score by preserving the diversity of the gut flora following FMT for UC. Current Controlled Trial NCT02016469 . Registered 10 November 2013.

  2. Addressing diversion effects

    PubMed Central

    Resnik, David B.

    2015-01-01

    Alan Wertheimer argues that those who promulgate principles of research ethics have a responsibility to take into account the diversion effects of those principles. In this commentary, I argue that Wertheimer's proposal that diversion effects should be considered when promulgating principles of research ethics makes sense, but it often may be best to deal with these effects once a principle has been accepted and implemented, rather than focusing on them at the outset. PMID:27774202

  3. Addressing diversion effects.

    PubMed

    Resnik, David B

    2015-07-01

    Alan Wertheimer argues that those who promulgate principles of research ethics have a responsibility to take into account the diversion effects of those principles. In this commentary, I argue that Wertheimer's proposal that diversion effects should be considered when promulgating principles of research ethics makes sense, but it often may be best to deal with these effects once a principle has been accepted and implemented, rather than focusing on them at the outset.

  4. Local Effects of Delayed Food

    PubMed Central

    Davison, Michael; Baum, William M

    2007-01-01

    Five pigeons were trained on a procedure in which seven concurrent variable-interval schedules arranged seven different food–rate ratios in random sequence in each session. Each of these components lasted for 10 response-produced food deliveries, and components were separated by 10-s blackouts. We varied delays to food (signaled by blackout) between the two response alternatives in an experiment with three phases: In Phase 1, the delay on one alternative was 0 s, and the other was varied between 0 and 8 s; in Phase 2, both delays were equal and were varied from 0 to 4 s; in Phase 3, the two delays summed to 8 s, and each was varied from 1 to 7 s. The results showed that increasing delay affected local choice, measured by a pulse in preference, in the same way as decreasing magnitude, but we found also that increasing the delay at the other alternative increased local preference. This result casts doubt on the traditional view that a reinforcer strengthens a response depending only on the reinforcer's value discounted by any response–reinforcer delay. The results suggest that food guides, rather than strengthens, behavior. PMID:17465314

  5. Behavioral effects of delayed timeouts from reinforcement.

    PubMed

    Byrne, Tom; Poling, Alan

    2017-02-14

    Timeouts are sometimes used in applied settings to reduce target responses, and in some circumstances delays are unavoidably imposed between the onset of a timeout and the offset of the response that produces it. The present study examined the effects of signaled and unsignaled timeouts in rats exposed to concurrent fixed-ratio 1 fixed-ratio 1 schedules of food delivery, where each response on one lever, the location of which changed across conditions, produced both food and a delayed 10-s timeout. Delays of 0 to 38 s were examined. Delayed timeouts often, but not always, substantially reduced the number of responses emitted on the lever that produced timeouts relative to the number emitted on the lever that did not produce timeouts. In general, greater sensitivity was observed to delayed timeouts when they were signaled. These results demonstrate that delayed timeouts, like other delayed consequences, can affect behavior, albeit less strongly than immediate consequences.

  6. Local Effects of Delayed Food

    ERIC Educational Resources Information Center

    Davison, Michael; Baum, William M.

    2007-01-01

    Five pigeons were trained on a procedure in which seven concurrent variable-interval schedules arranged seven different food-rate ratios in random sequence in each session. Each of these components lasted for 10 response-produced food deliveries, and components were separated by 10-s blackouts. We varied delays to food (signaled by blackout)…

  7. Local Effects of Delayed Food

    ERIC Educational Resources Information Center

    Davison, Michael; Baum, William M.

    2007-01-01

    Five pigeons were trained on a procedure in which seven concurrent variable-interval schedules arranged seven different food-rate ratios in random sequence in each session. Each of these components lasted for 10 response-produced food deliveries, and components were separated by 10-s blackouts. We varied delays to food (signaled by blackout)…

  8. Effects of elongation delay in transcription dynamics.

    PubMed

    Zhang, Xuan; Jin, Huiqin; Yang, Zhuoqin; Lei, Jinzhi

    2014-12-01

    In the transcription process, elongation delay is induced by the movement of RNA polymerases (RNAP) along the DNA sequence, and can result in changes in the transcription dynamics. This paper studies the transcription dynamics that involved the elongation delay and effects of cell division and DNA replication. The stochastic process of gene expression is modeled with delay chemical master equation with periodic coefficients, and is studied numerically through the stochastic simulation algorithm with delay. We show that the average transcription level approaches to a periodic dynamics over cell cycles at homeostasis, and the elongation delay can reduce the transcription level and increase the transcription noise. Moreover, the transcription elongation can induce bimodal distribution of mRNA levels that can be measured by the techniques of flow cytometry.

  9. Isolation Effect in Immediate and Delayed Recall

    ERIC Educational Resources Information Center

    Bellezza, Francis S.; Cheney, Terry L.

    1973-01-01

    If the hypothesis of selective rehearsal is used to account for the isolation effect, then the recall of isolated items will depend both on the serial position of the isolated item and on whether recall is immediate or delayed. (Author)

  10. Isolation Effect in Immediate and Delayed Recall

    ERIC Educational Resources Information Center

    Bellezza, Francis S.; Cheney, Terry L.

    1973-01-01

    If the hypothesis of selective rehearsal is used to account for the isolation effect, then the recall of isolated items will depend both on the serial position of the isolated item and on whether recall is immediate or delayed. (Author)

  11. Delayed hemorrhagic complications after flow diversion for intracranial aneurysms: a literature overview

    PubMed Central

    Rouchaud, Aymeric; Brinjikji, Waleed; Lanzino, Giuseppe; Cloft, Harry J.; Kadirvel, Ramanthan; Kallmes, David F.

    2016-01-01

    Background Delayed aneurysm rupture and delayed intraparenchymal hemorrhages (DIPH) are poorly understood and often fatal complications of flow diversion (FD) for intracranial aneurysms. The purpose of this study was to identify risk factors for these complications. Materials and Methods We performed a systematic review on post-FD delayed aneurysm rupture and DIPH. For each reported case we collected the following information: aneurysm location, size and rupture status, type of flow-diverter used, timing of the hemorrhage, and neurological outcome. We reported descriptive statistics of patients suffering DIPH and delayed aneurysm rupture to determine if there were any characteristics consistently present among patients with these complications. Results We identified 81 delayed aneurysms ruptures and 101 DIPH. 76.6% (45/58) of the delayed ruptures occurred within one month. The prognosis of delayed ruptures was poor, with 81.3% (61/75) experiencing death or poor neurological outcome. Giant aneurysms accounted for 46.3% of ruptures (31/67). 80.9% (55/68) of these aneurysms were initially unruptured. 17.8% (13/73) of the delayed ruptured aneurysms had prior or concomitant coiling. DIPHs were ipsilateral to the treated aneurysm in 82.2% (60/73) of cases. 86.0% (43/50) of the DIPH occurred within one month after FDS. Combined morbidity/mortality rate was 68.5% (50/73 following DIPH. 23.0% of DIPHs (14/61) occurred in patients with giant aneurysms. Conclusions Our study demonstrates that giant aneurysms represent almost 50% of delayed aneurysm ruptures in the flow-diverter literature. About 20% of delayed ruptures occurred despite associated coiling. A substantial proportion of DIPHs occur early following FDS treatment of giant aneurysms. PMID:26553302

  12. Modeling, Simulation and Performance Analysis of Multiple-Input Multiple-Output (MIMO) Systems with Multicarrier Time Delay Diversity Modulation

    DTIC Science & Technology

    2005-09-01

    MULTIPLE - INPUT MULTIPLE - OUTPUT ( MIMO ) SYSTEMS WITH MULTICARRIER TIME DELAY DIVERSITY MODULATION by Muhammad...SUBTITLE: Modeling, Simulation and Performance Analysis of Multiple - Input Multiple - Output ( MIMO ) Systems with Multicarrier Time Delay Diversity Modulation...MISO) and multiple - input multiple - output ( MIMO ) radio communication systems with space-time codes. A MISO system and MIMO

  13. Delayed onset muscle soreness: is massage effective?

    PubMed

    Nelson, Nicole

    2013-10-01

    Despite the widespread occurrence of delayed onset muscle soreness (DOMS), there is little consensus as to the exact cause or which treatments may be most effective at alleviating symptoms. Greater understanding of DOMS can give sports medicine and fitness professionals an opportunity to help prevent or speed recovery of this performance limiting condition. This article will review the DOMS literature, including the potential role of psychosocial factors and explore studies which involve massage therapy as a treatment modality. Articles from PubMed, MEDLINE, Google Scholar, and references from articles are included in this review. Search words and phrases included delayed onset muscle soreness, repeated bout effect, massage effectiveness, exercise induced muscle damage, and eccentric exercise.

  14. Angular dependence of Wigner time delay: Relativistic Effects

    NASA Astrophysics Data System (ADS)

    Mandal, A.; Deshmukh, P. C.; Manson, S. T.; Kkeifets, A. S.

    2016-05-01

    Laser assisted photoionization time delay mainly consists of two parts: Wigner time delay, and time delay in continuum-continuum transition. Wigner time delay results from the energy derivative of the phase of the photoionization amplitude (matrix element). In general, the photoionization time delay is not the same in all directions relative to the incident photon polarization, although when a single transition dominates the amplitude, the resultant time delay is essentially isotropic. The relativistic-random-phase approximation is employed to determine the Wigner time delay in photoionization from the outer np subshells of the noble gas atoms, Ne through Xe. The time delay is found to significantly depend on angle, as well as energy. The angular dependence of the time delay is found to be quite sensitive to atomic dynamics and relativistic effects, and exhibit strong energy and angular variation in the neighborhood of Cooper minima. Work supported by DOE, Office of Chemical Sciences and DST (India).

  15. The Effects of Delay of Feedback on a Delayed Concept Formation Transfer Task.

    ERIC Educational Resources Information Center

    Schroth, Marvin L.

    1992-01-01

    Delay and completeness of verbal information feedback were investigated within a transfer of learning paradigm involving concept formation. An experiment with 192 undergraduates indicates that, although delay of feedback (up to 30 seconds) slows speed of learning on the initial task, it has positive effects on the transfer task. (SLD)

  16. Delay time and Hartman effect in strain engineered graphene

    SciTech Connect

    Chen, Xi Deng, Zhi-Yong; Ban, Yue

    2014-05-07

    Tunneling times, including group delay and dwell time, are studied for massless Dirac electrons transmitting through a one-dimensional barrier in strain-engineered graphene. The Hartman effect, the independence of group delay on barrier length, is induced by the strain effect, and associated with the transmission gap and the evanescent mode. The influence of barrier height/length and strain modulus/direction on the group delay is also discussed, which provides the flexibility to control the group delay with applications in graphene-based devices. The relationship between group delay and dwell time is finally derived to clarify the nature of the Hartman effect.

  17. Propofol effects on atrial fibrillation wavefront delays.

    PubMed

    Cervigón, Raquel; Moreno, Javier; Millet, José; Pérez-Villacastín, Julián; Castells, Francisco

    2010-08-01

    Since the cardiac activity during atrial fibrillation (AF) may be influenced by autonomic modulations, in this study, a novel method to quantify the effects of the most common anesthetic agent (propofol) in AF ablation procedures is introduced. This study has two main objectives: first, to assess whether the sedation earlier to radio frequency ablation affects the arrhythmia itself, and second, to provide new information that contributes to a better understanding of the influence of the autonomic nervous system on AF. The methodology presented is based on the measurement of synchronization and delay indexes between two atrial activations at adjacent intracavitary electrodes. These parameters aim to estimate whether two activations at different sites may be caused by the same propagating wavefront, or otherwise, are the consequence of independent wavefronts. The results showed that the mentioned indexes have a different behavior at both atria: the right atrium becomes more synchronized with propofol administration, whereas the synchronization index decreases at the left atrium.

  18. Tunable delay time and Hartman effect in graphene magnetic barriers

    SciTech Connect

    Ban, Yue; Wang, Lin-Jun; Chen, Xi

    2015-04-28

    Tunable group delay and Hartman effect have been investigated for massless Dirac electrons in graphene magnetic barriers. In the presence of magnetic field, dwell time is found to be equal to net group delay plus the group delay contributing from the lateral shifts. The group delay times are discussed in both cases of normal and oblique incidence, to clarify the nature of Hartman effect. In addition, the group delay in transmission can be modulated from subluminality to superluminality by adjusting the magnetic field, which may also lead to potential applications in graphene-based microelectronics.

  19. Effect of speedup delay on shuttle bus schedule

    NASA Astrophysics Data System (ADS)

    Nagatani, Takashi

    2016-10-01

    We study the bus schedule in the shuttle bus transportation system controlled by speedup. The bus schedule is closely related to the dynamic motion of the bus. The motion of a shuttle bus depends on the inflow rate of passengers and the delayed speedup control. The delayed speedup control has an important effect on the dynamic motion of the bus. We present the delayed map model for the dynamics of the shuttle bus with the delayed speedup control. The bus motion changes from a stable state, through a periodic state, to a quasi-periodic state by the delayed speedup control. The return map of the tour time displays a smooth closed curve and the bus motion is quasi-periodic. The dynamic transition to the quasi-periodic motion changes greatly with the delay time. We clarify the effect of the delayed speedup control on the bus schedule.

  20. The effects of the framing of time on delay discounting.

    PubMed

    DeHart, William Brady; Odum, Amy L

    2015-01-01

    We examined the effects of the framing of time on delay discounting. Delay discounting is the process by which delayed outcomes are devalued as a function of time. Time in a titrating delay discounting task is often framed in calendar units (e.g., as 1 week, 1 month, etc.). When time is framed as a specific date, delayed outcomes are discounted less compared to the calendar format. Other forms of framing time; however, have not been explored. All participants completed a titrating calendar unit delay-discounting task for money. Participants were also assigned to one of two delay discounting tasks: time as dates (e.g., June 1st, 2015) or time in units of days (e.g., 5000 days), using the same delay distribution as the calendar delay-discounting task. Time framed as dates resulted in less discounting compared to the calendar method, whereas time framed as days resulted in greater discounting compared to the calendar method. The hyperboloid model fit best compared to the hyperbola and exponential models. How time is framed may alter how participants attend to the delays as well as how the delayed outcome is valued. Altering how time is framed may serve to improve adherence to goals with delayed outcomes.

  1. Resonance Effects in Photoemission Time Delays.

    PubMed

    Sabbar, M; Heuser, S; Boge, R; Lucchini, M; Carette, T; Lindroth, E; Gallmann, L; Cirelli, C; Keller, U

    2015-09-25

    We present measurements of single-photon ionization time delays between the outermost valence electrons of argon and neon using a coincidence detection technique that allows for the simultaneous measurement of both species under identical conditions. The analysis of the measured traces reveals energy-dependent time delays of a few tens of attoseconds with high energy resolution. In contrast to photoelectrons ejected through tunneling, single-photon ionization can be well described in the framework of Wigner time delays. Accordingly, the overall trend of our data is reproduced by recent Wigner time delay calculations. However, besides the general trend we observe resonance features occurring at specific photon energies. These features have been qualitatively reproduced and identified by a calculation using the multiconfigurational Hartree-Fock method, including the influence of doubly excited states and ionization thresholds.

  2. DELAYED EFFECTS OF RADIATION ON THE HUMAN CENTRAL NERVOUS SYSTEM. EARLY AND LATE DELAYED REACTIONS,

    DTIC Science & Technology

    multiple sclerosis and are not associated with degenerative vascular changes. This patient probably represents an extreme of the early delayed reaction reported by Scholz in dogs. There is clinical evidence suggesting that some degree of damage of this type occurs more frequently than has been suspected. The other patient had the late delayed reaction in which there are marked degenerative vascular alternations and severe destruction of the white matter with little cortical involvement. This patient is an extreme example of the well-documented late delayed effects of

  3. Effects of delay and probability combinations on discounting in humans.

    PubMed

    Cox, David J; Dallery, Jesse

    2016-10-01

    To determine discount rates, researchers typically adjust the amount of an immediate or certain option relative to a delayed or uncertain option. Because this adjusting amount method can be relatively time consuming, researchers have developed more efficient procedures. One such procedure is a 5-trial adjusting delay procedure, which measures the delay at which an amount of money loses half of its value (e.g., $1000 is valued at $500 with a 10-year delay to its receipt). Experiment 1 (n=212) used 5-trial adjusting delay or probability tasks to measure delay discounting of losses, probabilistic gains, and probabilistic losses. Experiment 2 (n=98) assessed combined probabilistic and delayed alternatives. In both experiments, we compared results from 5-trial adjusting delay or probability tasks to traditional adjusting amount procedures. Results suggest both procedures produced similar rates of probability and delay discounting in six out of seven comparisons. A magnitude effect consistent with previous research was observed for probabilistic gains and losses, but not for delayed losses. Results also suggest that delay and probability interact to determine the value of money. Five-trial methods may allow researchers to assess discounting more efficiently as well as study more complex choice scenarios. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Effects of delay and probability combinations on discounting in humans

    PubMed Central

    Cox, David J.; Dallery, Jesse

    2017-01-01

    To determine discount rates, researchers typically adjust the amount of an immediate or certain option relative to a delayed or uncertain option. Because this adjusting amount method can be relatively time consuming, researchers have developed more efficient procedures. One such procedure is a 5-trial adjusting delay procedure, which measures the delay at which an amount of money loses half of its value (e.g., $1000 is valued at $500 with a 10-year delay to its receipt). Experiment 1 (n = 212) used 5-trial adjusting delay or probability tasks to measure delay discounting of losses, probabilistic gains, and probabilistic losses. Experiment 2 (n = 98) assessed combined probabilistic and delayed alternatives. In both experiments, we compared results from 5-trial adjusting delay or probability tasks to traditional adjusting amount procedures. Results suggest both procedures produced similar rates of probability and delay discounting in six out of seven comparisons. A magnitude effect consistent with previous research was observed for probabilistic gains and losses, but not for delayed losses. Results also suggest that delay and probability interact to determine the value of money. Five-trial methods may allow researchers to assess discounting more efficiently as well as study more complex choice scenarios. PMID:27498073

  5. Delayed diversity for fade resistance in optical wireless communications through turbulent media

    NASA Astrophysics Data System (ADS)

    Trisno, Sugianto; Smolyaninov, Igor I.; Milner, Stuart D.; Davis, Christopher C.

    2004-10-01

    Atmospheric turbulence causes fluctuations in both the intensity and phase of the received signal in an optical wireless communication link. These fluctuations, often referred to as scintillation noise, lead to signal fading, which increase bit errors in digital communication links using intensity modulation and direct detection. The performance of an optical link can be improved by the use of a time delayed diversity technique, which takes advantage of the fact that the atmospheric path from transmitter to receiver is statistically independent for time intervals beyond the correlation time of the intensity fluctuations. We have designed and constructed a prototype optical wireless system using this scheme. Bit-error-rate measurements have been used to characterize the link performance for different delay periods under conditions of controlled simulated turbulence. It has been determined that link performance improves significantly, especially in strong turbulence. In addition, we have implemented orthogonal polarization modulation, which works especially well in optical wireless systems. In contrast to fiber optic communications, the polarization state of a laser beam is well preserved on a free space optical path.

  6. Why Do Rereading Lag Effects Depend on Test Delay?

    ERIC Educational Resources Information Center

    Rawson, Katherine A.

    2012-01-01

    In previous research, rereading after a long lag versus a short lag led to greater performance on delayed tests but not on immediate tests. The current study tested two accounts of why the effects of rereading lag depend on test delay. The "levels of representation" ("LOR") "hypothesis" states that the effects reflect…

  7. The health effects of cost-related treatment delays.

    PubMed

    Chen, Jie; Rizzo, John A; Rodriguez, Hector P

    2011-01-01

    The number of Americans who report delaying or forgoing necessary medical care because of cost concerns has increased markedly in recent years. Delaying or forgoing treatment may result in negative health effects, but empirical evidence is scarce. Using the merged data set of the Medical Expenditure Panel Survey and the National Health Interview Survey 2002-2006, the effect of delaying or forgoing medical care on ex post health status was estimated. Results indicate that people who delayed or forwent medical treatment were significantly less likely to report having excellent or very good ex post health status and had significantly lower quality-of-life scores compared with people who never delayed or forwent necessary medical care, controlling for socioeconomic and demographic factors, chronic medical conditions, and baseline health status. The Blinder-Oaxaca decomposition results suggest that expanding health insurance coverage can prevent 9% to 12% of the health decrements associated with delaying or forgoing medical treatment.

  8. Time-Delay Effects on Constitutive Gene Expression*

    NASA Astrophysics Data System (ADS)

    Feng, Yan-Ling; Dong, Jian-Min; Wang, Dan; Tang, Xu-Lei

    2017-09-01

    The dynamics of constitutive gene expression with delayed mRNA degradation is investigated, where the intrinsic noise caused by the small number of reactant molecules is introduced. It is found that the oscillatory behavior claimed in previous investigations does not appear in the approximation of small time delay, and the steady state distribution still follows the Poisson law. Furthermore, we introduce the extrinsic noise induced by surrounding environment to explore the effects of this noise and time delay on the Fano factor. Based on a delay Langevin equation and the corresponding Fokker–Planck equation, the distribution of mRNA copy-number is achieved analytically. The time delay and extrinsic noise play similar roles in the gene expression system, that is, they are able to result in the deviation of the Fano factor from 1 evidently. The measured Fano factor for constitutive gene expression is slightly larger than 1, which is perhaps attributed to the time-delay effect.

  9. Characterization of time delayed diversity to mitigate fading in atmospheric turbulence channels

    NASA Astrophysics Data System (ADS)

    Trisno, Sugianto; Smolyaninov, Igor I.; Milner, Stuart D.; Davis, Christopher C.

    2005-08-01

    Atmospheric turbulence is caused by inhomogeneities in the temperature and pressure of the atmosphere, resulting in random variations of the refractive index. A laser beam propagating through such turbulences experiences random amplitude and phase fluctuations, which can severely degrade the performance of free space optical (FSO) communication systems. In our time delayed diversity (TDD) technique, we transmit twice and take advantage of the fact that propagation along an atmospheric path is statistically uncorrelated with an earlier-time path for a time interval greater than the atmospheric turbulence correlation time. Communications performance is improved because the joint probability of error is less than the probability of error from individual channels. In this paper, we describe the theoretical and experimental analyses of FSO systems implementing this novel scheme in various performance scenarios. Theoretical models and performance of TDD systems are derived and characterized. The experimental performance results obtained under weak turbulence conditions are shown to be in good agreement with the theory. Related system design and implementation issues, such as: atmospheric turbulence statistics, laser beam depolarization, and diversity receiver architecture are also discussed.

  10. Effect of time delay on flying qualities: An update

    NASA Technical Reports Server (NTRS)

    Smith, R. E.; Sarrafian, S. K.

    1986-01-01

    Flying qualities problems of modern, full-authority electronic flight control systems are most often related to the introduction of additional time delay in aircraft response to a pilot input. These delays can have a significant effect on the flying qualities of the aircraft. Time delay effects are reexamined in light of recent flight test experience with aircraft incorporating new technology. Data from the X-29A forward-swept-wing demonstrator, a related preliminary in-flight experiment, and other flight observations are presented. These data suggest that the present MIL-F-8785C allowable-control system time delay specifications are inadequate or, at least, incomplete. Allowable time delay appears to be a function of the shape of the aircraft response following the initial delay. The cockpit feel system is discussed as a dynamic element in the flight control system. Data presented indicate that the time delay associated with a significant low-frequency feel system does not result in the predicted degradation in aircraft flying qualities. The impact of the feel system is discussed from two viewpoints: as a filter in the control system which can alter the initial response shape and, therefore, the allowable time delay, and as a unique dynamic element whose delay contribution can potentially be discounted by special pilot loop closures.

  11. Components of Effective Diversity Training Programmes.

    ERIC Educational Resources Information Center

    Wentling, Rose Mary; Palma-Rivas, Nilda

    1999-01-01

    Interviews with 12 diversity experts uncovered components of effective diversity training programs: management commitment and support, inclusion in strategic planning, attention to specific organizational needs, qualified trainers, mandatory attendance, inclusiveness, trust and confidentiality, accountability, and clearly focused evaluation. (SK)

  12. Effects of variable training, signaled and unsignaled delays, and d-amphetamine on delay-discounting functions.

    PubMed

    Slezak, Jonathan M; Anderson, Karen G

    2009-09-01

    One common procedure for obtaining delay-discounting functions consists of a choice between a larger reinforcer that is presented after an increasing delay and a smaller reinforcer that is always presented immediately within session. Repeating the same context of delay presentation (e.g. ascending delay order) in a discrete-choice paradigm, however, may lead to a perseverative response pattern when rats are used as subjects. The purpose of this study was to increase the variability in delay presentation (i.e. ascending and descending delays) in an attempt to reduce a perseverative response pattern and gain tighter control over choice by reinforcer amount and delay. For one group of rats (n = 8), delays to reinforcer presentation were differentially signaled by a flashing houselight and for one group of rats (n = 8) the delays were unsignaled. Effects of delay signal and d-amphetamine on choice were evaluated in both groups. Similar rates of delay discounting and area under the curve (AUC) were observed with both ascending and descending delay presentations and with signaled and unsignaled delays to reinforcement. Increasing the variability in delay order resulted in differences in the choice pattern during 0-s probe sessions. d-Amphetamine had little or no effect on AUC at low doses, but decreased AUC at the highest doses tested, that is, 1.0 and 1.7 mg/kg. Some of the changes in AUC after d-amphetamine administration may have been because of disruption in discrimination of the different food amounts.

  13. Reversing the Signaled Magnitude Effect in Delayed Matching to Sample: Delay-Specific Remembering?

    ERIC Educational Resources Information Center

    White, K. Geoffrey; Brown, Glenn S.

    2011-01-01

    Pigeons performed a delayed matching-to-sample task in which large or small reinforcers for correct remembering were signaled during the retention interval. Accuracy was low when small reinforcers were signaled, and high when large reinforcers were signaled (the signaled magnitude effect). When the reinforcer-size cue was switched from small to…

  14. Abolishing the effect of reinforcement delay on human causal learning.

    PubMed

    Buehner, Marc J; May, Jon

    2004-04-01

    Associative learning theory postulates two main determinants for human causal learning: contingency and contiguity. In line with such an account, participants in Shanks, Pearson, and Dickinson (1989) failed to discover causal relations involving delays of more than two seconds. More recent research has shown that the impact of contiguity and delay is mediated by prior knowledge about the timeframe of the causal relation in question. Buehner and May (2002, 2003) demonstrated that the detrimental effect of delay can be significantly reduced if reasoners are aware of potential delays. Here we demonstrate for the first time that the negative influence of delay can be abolished completely by a subtle change in the experimental instructions. Temporal contiguity is thus not essential for human causal learning.

  15. Effects of amphetamine on delay discounting in rats depend upon the manner in which delay is varied.

    PubMed

    Maguire, David R; Henson, Cedric; France, Charles P

    2014-12-01

    Whether stimulant drugs like amphetamine increase or decrease choice of larger delayed reinforcers over smaller immediately available reinforcers under delay discounting procedures can depend on several factors, including the order in which delay is presented. This study examined whether the order of delay presentation impacts drug effects on discounting in rats (n = 8) trained and tested under an ascending order, a descending order, as well as under a fixed delay condition. Responses on one lever delivered 1 food pellet immediately and responses on the other lever delivered 3 food pellets immediately or after a delay (4-32 s). In Experiment 1, the delay to the larger reinforcer varied within session and the order of delay presentation (ascending or descending) varied across conditions. In Experiment 2, the same delay value was presented in all blocks of the session (i.e., delay was fixed), and delay varied across conditions. Under the ascending order of delay, amphetamine (0.32-1.78 mg/kg) increased choice of the larger reinforcer in some rats and decreased choice in others. In the same rats responding under the descending and fixed delay conditions, amphetamine markedly decreased choice of the larger reinforcer even in the component associated with no delay. In some subjects, the effects of amphetamine differed depending on the manner in which delay was presented, indicating that drug-induced changes in performance were due, in part, to mechanisms other than altered sensitivity to reinforcer delay. These results also suggest that a history of responding under both orders of delay presentation can modulate drug effects. This article is part of the Special Issue entitled 'CNS Stimulants'.

  16. 42 CFR 435.965 - Delay of effective date.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... ISLANDS, AND AMERICAN SAMOA Eligibility in the States and District of Columbia Income and Eligibility... the Secretary of Agriculture and the Secretary of Labor, grant a delay in the effective date of §§...

  17. The spacing effect in immediate and delayed free recall.

    PubMed

    Godbole, Namrata R; Delaney, Peter F; Verkoeijen, Peter P J L

    2014-01-01

    Spacing repetitions improves learning relative to massing repetitions (the spacing effect). While most studies have examined the spacing effect at short retention intervals, there are contradictory claims about its fate at a delay. Certain empirical findings suggest that the spacing effect persists at a delay. However, a recent theoretical account proposes that in free recall the spacing effect should disappear at a delay. The few studies that have examined the spacing effect at a delay are sub-optimally designed, preventing an unbiased conclusion. The current study used incidental learning and controlled recency and encoding strategy in order to examine the effect of delay on the recall of spaced items within a free recall paradigm. The results demonstrated that the spacing effect persists after a delay. The results point to an important dissociation between intentional forgetting and context-change designs (which produce more forgetting of spaced than massed items) and the passage of time (which produces similar forgetting of spaced and massed items).

  18. 42 CFR 435.965 - Delay of effective date.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 4 2014-10-01 2014-10-01 false Delay of effective date. 435.965 Section 435.965... Verification Requirements § 435.965 Delay of effective date. (a) If the agency submits, by May 29, 1986, a plan....910 and 435.940 through 435.960, but not beyond September 30, 1986. (b) The Secretary may not grant...

  19. Child, family, and childcare predictors of delayed school entry and kindergarten retention among linguistically and ethnically diverse children.

    PubMed

    Winsler, Adam; Hutchison, Lindsey A; De Feyter, Jessica J; Manfra, Louis; Bleiker, Charles; Hartman, Suzanne C; Levitt, Jerome

    2012-09-01

    Concern about kindergarten retention is on the rise within the current climate of high-stakes testing and escalating kindergarten expectations. Kindergarten retention has been linked in previous research to various risk factors such as poverty, low maternal education, single parent status, minority status, English language learner (ELL) status, and male gender. However, these factors are also associated with poor school readiness and low kindergarten performance--the very reasons children are retained in the 1st place. This study teases apart unique and combined predictors of delayed entry into kindergarten and kindergarten retention with a large (n = 13,191) ethnically diverse, at-risk sample of children. Delayed kindergarten entry was rare for this sample but more likely among boys, native English speakers, those with poorer school readiness, less maternal education, and greater resources, and those who attended childcare rather than public school prekindergarten (pre-K) at age 4 years. Boys were more likely to be retained in kindergarten, but only because of their poorer school readiness. After strong effects for age 4 school readiness were controlled, only poverty, ELL status, and preschool program attendance predicted retention. ELL students were less likely to be retained than were native speakers, and those who attended public school pre-K programs were less likely to be retained, compared with those in childcare at age 4 years. After controlling for children's actual performance in kindergarten their 1st time, Caucasian children and children with lower language and social skills at age 4 years were more likely to repeat kindergarten.

  20. Delays induce novel stochastic effects in negative feedback gene circuits.

    PubMed

    Zavala, Eder; Marquez-Lago, Tatiana T

    2014-01-21

    Stochastic models of reaction networks are widely used to depict gene expression dynamics. However, stochastic does not necessarily imply accurate, as subtle assumptions can yield erroneous results, masking key discrete effects. For instance, transcription and translation are not instantaneous processes-explicit delays separate their initiation from the appearance of their functional products. However, delays are often ignored in stochastic, single-gene expression models. By consequence, effects such as delay-induced stochastic oscillations at the single-cell level have remained relatively unexplored. Here, we present a systematic study of periodicity and multimodality in a simple gene circuit with negative feedback, analyzing the influence of negative feedback strength and transcriptional/translational delays on expression dynamics. We demonstrate that an oscillatory regime emerges through a Hopf bifurcation in both deterministic and stochastic frameworks. Of importance, a shift in the stochastic Hopf bifurcation evidences inaccuracies of the deterministic bifurcation analysis. Furthermore, noise fluctuations within stochastic oscillations decrease alongside increasing values of transcriptional delays and within a specific range of negative feedback strengths, whereas a strong feedback is associated with oscillations triggered by bursts. Finally, we demonstrate that explicitly accounting for delays increases the number of accessible states in the multimodal regime, and also introduces features typical of excitable systems.

  1. Delays Induce Novel Stochastic Effects in Negative Feedback Gene Circuits

    PubMed Central

    Zavala, Eder; Marquez-Lago, Tatiana T.

    2014-01-01

    Stochastic models of reaction networks are widely used to depict gene expression dynamics. However, stochastic does not necessarily imply accurate, as subtle assumptions can yield erroneous results, masking key discrete effects. For instance, transcription and translation are not instantaneous processes—explicit delays separate their initiation from the appearance of their functional products. However, delays are often ignored in stochastic, single-gene expression models. By consequence, effects such as delay-induced stochastic oscillations at the single-cell level have remained relatively unexplored. Here, we present a systematic study of periodicity and multimodality in a simple gene circuit with negative feedback, analyzing the influence of negative feedback strength and transcriptional/translational delays on expression dynamics. We demonstrate that an oscillatory regime emerges through a Hopf bifurcation in both deterministic and stochastic frameworks. Of importance, a shift in the stochastic Hopf bifurcation evidences inaccuracies of the deterministic bifurcation analysis. Furthermore, noise fluctuations within stochastic oscillations decrease alongside increasing values of transcriptional delays and within a specific range of negative feedback strengths, whereas a strong feedback is associated with oscillations triggered by bursts. Finally, we demonstrate that explicitly accounting for delays increases the number of accessible states in the multimodal regime, and also introduces features typical of excitable systems. PMID:24461022

  2. Effect of delay mismatch in Pyragas feedback control

    NASA Astrophysics Data System (ADS)

    Purewal, A. S.; Postlethwaite, C. M.; Krauskopf, B.

    2014-11-01

    Pyragas time-delayed feedback is a control scheme designed to stabilize unstable periodic orbits, which occur naturally in many nonlinear dynamical systems. It has been successfully implemented in a number of applications, including lasers and chemical systems. The control scheme targets a specific unstable periodic orbit by adding a feedback term with a delay chosen as the period of the unstable periodic orbit. However, in an experimental or industrial environment, obtaining the exact period or setting the delay equal to the exact period of the target periodic orbit may be difficult. This could be due to a number of factors, such as incomplete information on the system or the delay being set by inaccurate equipment. In this paper, we evaluate the effect of Pyragas control on the prototypical generic subcritical Hopf normal form when the delay is close to but not equal to the period of the target periodic orbit. Specifically, we consider two cases: first, a constant, and second, a linear approximation of the period. We compare these two cases to the case where the delay is set exactly to the target period, which serves as the benchmark case. For this comparison, we construct bifurcation diagrams and determine any regions where a stable periodic orbit close to the target is stabilized by the control scheme. In this way, we find that at least a linear approximation of the period is required for successful stabilization by Pyragas control.

  3. The Effects of Attending a Diverse College

    ERIC Educational Resources Information Center

    Hinrichs, Peter

    2011-01-01

    The question of whether there are benefits to be obtained from having a diverse student body is a key issue in the debate over affirmative action. This paper estimates the effects of college racial diversity on post-college earnings, civic behavior, and satisfaction with the college attended. I use the Beginning Postsecondary Students survey,…

  4. Effect of exposure delay of concrete into aggressive environment

    NASA Astrophysics Data System (ADS)

    Abimouloud, Youcef; Kriker, Abdelouahed

    2016-07-01

    Some regions in the world suffered since several years from environmental problems such as underground level water rising. Water table effects durability of concrete implantation in the underground by the ease of luckless chemical elements ingress mainly through concrete the foundations of structures such as sulfate, chloride, and acids. For that reason a lot of foundations structures were made with SRPC (sulfate resisting Portland cement). This study is a contribution to assess the effect of exposure delay of concrete into aggressive fields, as a kind of cure which protects concrete from aggressive factors and allows it to acquire the needed strength. The study has shown that concrete exposure delay into aggressive environment is not a kind of cure mainly for concrete made with SRPC. Concrete with SRPC immediately exposed to aggressive environment shows a better mechanical resistance than concrete that has known exposure delay.

  5. Effects of Acute and Chronic Cocaine Administration on Titrating-Delay Matching-to-Sample Performance

    ERIC Educational Resources Information Center

    Kangas, Brian D.; Branch, Marc N.

    2012-01-01

    The effects of cocaine were examined under a titrating-delay matching-to-sample procedure. In this procedure, the delay between sample stimulus offset and comparison stimuli onset adjusts as a function of the subject's performance. Specifically, matches increase the delay and mismatches decrease the delay. Titrated delay values served as the…

  6. Effects of Acute and Chronic Cocaine Administration on Titrating-Delay Matching-to-Sample Performance

    ERIC Educational Resources Information Center

    Kangas, Brian D.; Branch, Marc N.

    2012-01-01

    The effects of cocaine were examined under a titrating-delay matching-to-sample procedure. In this procedure, the delay between sample stimulus offset and comparison stimuli onset adjusts as a function of the subject's performance. Specifically, matches increase the delay and mismatches decrease the delay. Titrated delay values served as the…

  7. Catastrophizing delays the analgesic effect of distraction

    PubMed Central

    Campbell, Claudia M.; Witmer, Kenny; Simango, Mpepera; Carteret, Alene; Loggia, Marco L.; Campbell, James N.; Haythornthwaite, Jennifer A.; Edwards, Robert R.

    2009-01-01

    Behavioral analgesic techniques such as distraction reduce pain in both clinical and experimental settings. Individuals differ in the magnitude of distraction-induced analgesia, and additional study is needed to identify the factors that influence the pain relieving effects of distraction. Catastrophizing, a set of negative emotional and cognitive processes, is widely recognized to be associated with increased reports of pain. We sought to evaluate the relationship between catastrophizing and distraction analgesia. Healthy participants completed three sessions in a randomized order. In one session (Pain Alone), pain was induced by topical application of a 10% capsaicin cream and simultaneous administration of a tonic heat stimulus. In another session (Pain + Distraction), identical capsaicin+heat application procedures were followed, but subjects played video games that required a high level of attention. During both sessions, verbal ratings of pain were obtained and participants rated their degree of catastrophizing. During the other session (Distraction Alone) subjects played the video games in the absence of any pain stimulus. Pain was rated significantly lower during the distraction session compared to the “pain alone” session. In addition, high catastrophizers rated pain significantly higher regardless of whether the subjects were distracted. Catastrophizing did not influence the overall degree of distraction analgesia; however, early in the session high catastrophizers had little distraction analgesia, though later in the session low and high catastrophizers rated pain similarly. These results suggest that both distraction and catastrophizing have substantial effects on experimental pain in normal subjects and these variables interact as a function of time. PMID:20188470

  8. Catastrophizing delays the analgesic effect of distraction.

    PubMed

    Campbell, Claudia M; Witmer, Kenny; Simango, Mpepera; Carteret, Alene; Loggia, Marco L; Campbell, James N; Haythornthwaite, Jennifer A; Edwards, Robert R

    2010-05-01

    Behavioral analgesic techniques such as distraction reduce pain in both clinical and experimental settings. Individuals differ in the magnitude of distraction-induced analgesia, and additional study is needed to identify the factors that influence the pain relieving effects of distraction. Catastrophizing, a set of negative emotional and cognitive processes, is widely recognized to be associated with increased reports of pain. We sought to evaluate the relationship between catastrophizing and distraction analgesia. Healthy participants completed three sessions in a randomized order. In one session (Pain Alone), pain was induced by topical application of a 10% capsaicin cream and simultaneous administration of a tonic heat stimulus. In another session (Pain+Distraction), identical capsaicin+heat application procedures were followed, but subjects played video games that required a high level of attention. During both sessions, verbal ratings of pain were obtained and participants rated their degree of catastrophizing. During the other session (Distraction Alone) subjects played the video games in the absence of any pain stimulus. Pain was rated significantly lower during the distraction session compared to the "Pain Alone" session. In addition, high catastrophizers rated pain significantly higher regardless of whether the subjects were distracted. Catastrophizing did not influence the overall degree of distraction analgesia; however, early in the session high catastrophizers had little distraction analgesia, though later in the session low and high catastrophizers rated pain similarly. These results suggest that both distraction and catastrophizing have substantial effects on experimental pain in normal subjects and these variables interact as a function of time. Copyright 2009 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  9. Effect of multiple time-delay on vibrational resonance.

    PubMed

    Jeevarathinam, C; Rajasekar, S; Sanjuán, M A F

    2013-03-01

    We report our investigation on the effect of multiple time-delay on vibrational resonance in a single Duffing oscillator and in a system of n Duffing oscillators coupled unidirectionally and driven by both a low- and a high-frequency periodic force. For the single oscillator, we obtain analytical expressions for the response amplitude Q and the amplitude g of the high-frequency force at which resonance occurs. The regions in parameter space of enhanced Q at resonance, as compared to the case in absence of time-delay, show a bands-like structure. For the two-coupled oscillators, we explain all the features of variation of Q with the control parameter g. For the system of n-coupled oscillators with a single time-delay coupling, the response amplitudes of the oscillators are shown to be independent of the time-delay. In the case of a multi time-delayed coupling, undamped signal propagation takes place for coupling strength (δ) above a certain critical value (denoted as δu). Moreover, the response amplitude approaches a limiting value QL with the oscillator number i. We obtain analytical expressions for both δu and QL.

  10. Gompertzian stochastic model with delay effect to cervical cancer growth

    NASA Astrophysics Data System (ADS)

    Mazlan, Mazma Syahidatul Ayuni binti; Rosli, Norhayati binti; Bahar, Arifah

    2015-02-01

    In this paper, a Gompertzian stochastic model with time delay is introduced to describe the cervical cancer growth. The parameters values of the mathematical model are estimated via Levenberg-Marquardt optimization method of non-linear least squares. We apply Milstein scheme for solving the stochastic model numerically. The efficiency of mathematical model is measured by comparing the simulated result and the clinical data of cervical cancer growth. Low values of Mean-Square Error (MSE) of Gompertzian stochastic model with delay effect indicate good fits.

  11. Gompertzian stochastic model with delay effect to cervical cancer growth

    SciTech Connect

    Mazlan, Mazma Syahidatul Ayuni binti; Rosli, Norhayati binti; Bahar, Arifah

    2015-02-03

    In this paper, a Gompertzian stochastic model with time delay is introduced to describe the cervical cancer growth. The parameters values of the mathematical model are estimated via Levenberg-Marquardt optimization method of non-linear least squares. We apply Milstein scheme for solving the stochastic model numerically. The efficiency of mathematical model is measured by comparing the simulated result and the clinical data of cervical cancer growth. Low values of Mean-Square Error (MSE) of Gompertzian stochastic model with delay effect indicate good fits.

  12. Control of epidemics on complex networks: Effectiveness of delayed isolation

    NASA Astrophysics Data System (ADS)

    Pereira, Tiago; Young, Lai-Sang

    2015-08-01

    We study isolation as a means to control epidemic outbreaks in complex networks, focusing on the consequences of delays in isolating infected nodes. Our analysis uncovers a tipping point: if infected nodes are isolated before a critical day dc, the disease is effectively controlled, whereas for longer delays the number of infected nodes climbs steeply. We show that dc can be estimated explicitly in terms of network properties and disease parameters, connecting lowered values of dc explicitly to heterogeneity in degree distribution. Our results reveal also that initial delays in the implementation of isolation protocols can have catastrophic consequences in heterogeneous networks. As our study is carried out in a general framework, it has the potential to offer insight and suggest proactive strategies for containing outbreaks of a range of serious infectious diseases.

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

    PubMed

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

    2014-02-01

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

  14. A rapid bioassessment of stream diversion effects

    NASA Astrophysics Data System (ADS)

    Pepin, D. M.; Albano, C. M.; Poff, N. L.

    2005-05-01

    Ecologists recognize that flow alterations imposed by dams impair water quality and many ecosystem processes. However, there is little empirical evidence addressing the ecological effects of stream dewatering through flow diversion. Intensive, multi-year sampling of macroinvertebrates and periphyton from streams in a single subalpine basin in Colorado has shown reduced abundance and diversity of macroinvertebrates and increased periphyton production in diverted reaches. This research suggests that ecosystem structure and function can be affected by diversion-mediated environmental changes. Our rapid bioassessment investigated the generality of the macroinvertebrate response to diversion. Following established EPA methods, we sampled 15 diverted streams across a range of watershed areas and diversion operation categories throughout Colorado and southern Wyoming over 4 days in September, 2004. Scoring of habitat variables demonstrated that diversion severely reduced habitat quality at all sites, compared to upstream reference sites, irrespective of the operational category of diversion. Macroinvertebrate abundance, richness, and evenness were reduced in poor-condition habitats. These results suggest that diversions of all types have the potential to depress basal food web members and thus likely diminish production of higher trophic levels in both the stream and adjacent riparian zone.

  15. Effects of Ion Irradiation on Seedlings Growth Monitored by Ultraweak Delayed Luminescence.

    PubMed

    Grasso, Rosaria; Abe, Tomoko; Cirrone, Giuseppe A P; Cuttone, Giacomo; Gulino, Marisa; Musumeci, Francesco; Romano, Francesco; Ryuto, Hiromichi; Scordino, Agata

    2016-01-01

    The optical technique based on the measurement of delayed luminescence emitted from the biological samples has demonstrated its ability to provide valid and predictive information on the functional status of various biological systems. We want to extend this technique to study the effect of ionizing radiation on biological systems. In particular we are interested in the action of ion beams, used for therapeutic purposes or to increase the biological diversity. In general, the assessment of the damage that radiation produces both in the target objects and in the surrounding tissues, requires considerable time because is based on biochemical analysis or on the examination of the evolution of the irradiated systems. The delayed luminescence technique could help to simplify this investigation. We have so started our studies performing irradiations of some relatively simple vegetable models. In this paper we report results obtained from mung bean (Vigna radiata) seeds submitted to a 12C ion beam at the energy of 62 MeV/nucleon. The dry seeds were irradiated at doses from 50 to 7000 Gy. The photoinduced delayed luminescence of each seed before and after ion irradiation was measured. The growth of seedlings after irradiation was compared with that of untreated seeds. A growth reduction on increasing the dose was registered. The results show strong correlations between the ion irradiation dose, seeds growth and delayed luminescence intensity. In particular, the delayed luminescence intensity is correlated by a logistic function to the seedlings elongation and, after performing a suitable measurement campaign based on blind tests, it could become a tool able to predict the growth of seeds after ion irradiation. Moreover these results demonstrate that measurements of delayed luminescence could be used as a fast and non-invasive technique to check the effects of ion beams on relatively simple biological systems.

  16. Effects of Ion Irradiation on Seedlings Growth Monitored by Ultraweak Delayed Luminescence

    PubMed Central

    Abe, Tomoko; Cirrone, Giuseppe A. P.; Cuttone, Giacomo; Gulino, Marisa; Musumeci, Francesco; Romano, Francesco; Ryuto, Hiromichi; Scordino, Agata

    2016-01-01

    The optical technique based on the measurement of delayed luminescence emitted from the biological samples has demonstrated its ability to provide valid and predictive information on the functional status of various biological systems. We want to extend this technique to study the effect of ionizing radiation on biological systems. In particular we are interested in the action of ion beams, used for therapeutic purposes or to increase the biological diversity. In general, the assessment of the damage that radiation produces both in the target objects and in the surrounding tissues, requires considerable time because is based on biochemical analysis or on the examination of the evolution of the irradiated systems. The delayed luminescence technique could help to simplify this investigation. We have so started our studies performing irradiations of some relatively simple vegetable models. In this paper we report results obtained from mung bean (Vigna radiata) seeds submitted to a 12C ion beam at the energy of 62 MeV/nucleon. The dry seeds were irradiated at doses from 50 to 7000 Gy. The photoinduced delayed luminescence of each seed before and after ion irradiation was measured. The growth of seedlings after irradiation was compared with that of untreated seeds. A growth reduction on increasing the dose was registered. The results show strong correlations between the ion irradiation dose, seeds growth and delayed luminescence intensity. In particular, the delayed luminescence intensity is correlated by a logistic function to the seedlings elongation and, after performing a suitable measurement campaign based on blind tests, it could become a tool able to predict the growth of seeds after ion irradiation. Moreover these results demonstrate that measurements of delayed luminescence could be used as a fast and non-invasive technique to check the effects of ion beams on relatively simple biological systems. PMID:27936220

  17. Role of the Cerebellum in Adaptation to Delayed Action Effects.

    PubMed

    Cao, Liyu; Veniero, Domenica; Thut, Gregor; Gross, Joachim

    2017-08-21

    Actions are typically associated with sensory consequences. For example, knocking at a door results in predictable sounds. These self-initiated sensory stimuli are known to elicit smaller cortical responses compared to passively presented stimuli, e.g., early auditory evoked magnetic fields known as M100 and M200 components are attenuated. Current models implicate the cerebellum in the prediction of the sensory consequences of our actions. However, causal evidence is largely missing. In this study, we introduced a constant delay (of 100 ms) between actions and action-associated sounds, and we recorded magnetoencephalography (MEG) data as participants adapted to the delay. We found an increase in the attenuation of the M100 component over time for self-generated sounds, which indicates cortical adaptation to the introduced delay. In contrast, no change in M200 attenuation was found. Interestingly, disrupting cerebellar activity via transcranial magnetic stimulation (TMS) abolished the adaptation of M100 attenuation, while the M200 attenuation reverses to an M200 enhancement. Our results provide causal evidence for the involvement of the cerebellum in adapting to delayed action effects, and thus in the prediction of the sensory consequences of our actions. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  18. Neuromodulation of delay discounting, the reflection effect, and cigarette consumption

    PubMed Central

    Sheffer, Christine E; Mennemeier, Mark; Landes, Reid D; Bickel, Warren K; Brackman, Sharon; Dornhoffer, John; Kimbrell, Timothy; Brown, Ginger

    2013-01-01

    Cigarette smokers and substance users discount the value of delayed outcomes more steeply than non-users. Higher discounting rates are associated with relapse and poorer treatment outcomes. The left dorsolateral prefontal cortex (DLPFC) exerts an inhibitory influence on impulsive or seductive choices and greater activity in the prefrontal cortex is associated with lower discounting rates. We hypothesized that increasing activity in the left DLPFC with high frequency repetitive transcranial magnetic stimulation (HF rTMS) would decrease delay discounting and decrease impulsive decision-making in a gambling task as well as decrease cigarette consumption, similar to other studies. In this single-blind, within-subjects design, smokers with no intention to quit (n=47) and nonsmokers (n=19) underwent three counterbalanced sessions of HF rTMS (20Hz, 10Hz, sham) delivered over the left DLPFC. Tasks were administered at baseline and after each stimulation session. Stimulation decreased discounting of monetary gains (F[3,250]=4.46, p<.01), but increased discounting of monetary losses (F[3,246]=4.30, p<.01), producing a reflection effect, normally absent in delay discounting. Stimulation had no effect on cigarette consumption. These findings provide new insights into cognitive processes involved with decision-making and cigarette consumption and suggest that like all medications for substance dependence, HF rTMS is likely to be most effective when paired with cognitive-behavioral interventions. PMID:23518286

  19. Overt Verbalization and Delay Behavior in Children: The Effects of Evaluative Statements and Freedom of Choice.

    ERIC Educational Resources Information Center

    Toner, Ignatius J.

    The maintenance of self-imposed delay of gratification by preschool children was briefly examined in two studies. One study investigated the effects of overt verbalization on the delay behavior of 75 preschool children. Children who periodically spoke of the delayed reward during the delay task, regardless of whether they spoke positively or…

  20. Formulation and solution of the delayed gamma dose rate problem using the concept of effective delayed gamma production cross section

    SciTech Connect

    Liew, S.L.; Ku, L.P.

    1989-06-01

    With appropriate approximations, the delayed gamma dose rate problem can be formulated in terms of the effective delayed gamma production cross section. The coupled neutron-delayed-gamma transport equations then take the same form as the coupled neutron-prompt-gamma transport equations and they can, therefore, be solved directly in the same manner. This eliminates the need for the tedious and error prone flux coupling step in conventional calculations. Mathematical formulation and solution algorithms are derived. The advantages of this method are illustrated by an example of its application in the solution of a practical design problem. 62 refs., 10 figs., 1 tab.

  1. Communicative Interactions of Mildly Delayed and Normally Developing Preschool Children: Effects of Listener's Developmental Level.

    ERIC Educational Resources Information Center

    Guralnick, Michael J.; Paul-Brown, Diane

    1986-01-01

    The communicative interactions of 32 mildly delayed and normally developing preschoolers were recorded during free play in a mainstreamed program. Analyses of syntactic complexity, semantic diversity, functional aspects of speech, and the use of selected discourse devices indicated that mildly delayed children adjusted important characteristics of…

  2. Communicative Interactions of Mildly Delayed and Normally Developing Preschool Children: Effects of Listener's Developmental Level.

    ERIC Educational Resources Information Center

    Guralnick, Michael J.; Paul-Brown, Diane

    1986-01-01

    The communicative interactions of 32 mildly delayed and normally developing preschoolers were recorded during free play in a mainstreamed program. Analyses of syntactic complexity, semantic diversity, functional aspects of speech, and the use of selected discourse devices indicated that mildly delayed children adjusted important characteristics of…

  3. Rapid and delayed effects of epidermal growth factor on gluconeogenesis.

    PubMed Central

    Soler, C; Soley, M

    1993-01-01

    Most reports on the effects of epidermal growth factor (EGF) on gluconeogenesis have indicated that such effects depend on the substrate used and are only observable after a lag time of 30-40 min. Recently, an immediate and transient effect of EGF on glucose synthesis was described in a perfused liver system. Here we extend the study of the effect of EGF on gluconeogenesis to isolated hepatocytes from fasted rats. The delayed effect of EGF on gluconeogenesis was studied by adding the substrate 40 min after the peptide. Under these conditions EGF increased glucose synthesis from pyruvate, decreased it when the substrate was lactate or glycerol and did not modify gluconeogensis from fructose or dihydroxyacetone. EGF did not affect the metabolic flux through glycolysis, determined as the production of lactate+pyruvate from 30 mM glucose. Furthermore, EGF did not modify the metabolic flux through pyruvate kinase, determined as the production of lactate+pyruvate from 1 mM dihydroxyacetone. The differing effects of EGF on gluconeogenesis depending on the substrate used can be explained by the effects of EGF on the cytosolic redox state (measured as the lactate/pyruvate ratio). About 20 min after the addition of EGF, the mitochondrial redox state (measured as the 3-hydroxybutyrate/acetoacetate ratio) decreased. This effect of EGF was blocked by ammonium, which also abolished the effect of the peptide on gluconeogenesis. Thus the effect of EGF at the mitochondrial level appears to be necessary for its effects on gluconeogenesis. Taken together, our results indicate that the delayed effects of EGF on gluconeogenesis are secondary to the effects of the peptide at both the mitochondrial and cytosolic levels. In addition to these delayed effects, we observed that EGF rapidly and transiently stimulated glucose synthesis from lactate, decreased the cytosolic redox state and increased oxygen consumption. All of these rapid effects required the presence of extracellular calcium

  4. Examining the Effects of a Highly Rated Science Curriculum Unit on Diverse Students: Results from a Planning Grant

    ERIC Educational Resources Information Center

    Lynch, Sharon; Kuipers, Joel; Pyke, Curtis; Szesze, Michael

    2005-01-01

    This article reports on the results of a planning grant studying the effects of a highly rated curriculum unit on a diverse student population. The treatment was introduced to 1500 eighth grade students in five middle schools selected for their ethnic, linguistic, and socioeconomic diversity. Students were given pre-, post-, and delayed posttests…

  5. Effect of Departure Delays on Manned Mars Mission Selection

    NASA Technical Reports Server (NTRS)

    Desai, Prasun N.; Tartabini, Paul V.

    1995-01-01

    This study determines the effect on the initial mass in low Earth orbit (IMLEO) of delaying departure from Mars and Earth by 5, 15, and 30 days, once a nominal mission to Mars has been selected. Additionally, the use of a deep-space maneuver (DSM) is considered in order to alleviate the IMLEO penalties. Three different classes of missions are analyzed, using chemical and nuclear thermal propulsion systems in the 2000-2025 time frame: opposition, conjunction, and fast-transfer conjunction. The results indicate that Mars and Earth delays can lead to large IMLEO penalties. Opposition and fast-transfer conjunction-class missions have the highest IMLEO penalties, upwards of 432.4 and 1977.3 metric tons (mt), respectively. Conjunction-class missions, on the other hand, tend to be insensitive to Mars and Earth delays, having IMLEO penalties under 103.5 mt. As expected, nuclear thermal propulsion had significantly lower IMLEO penalties than chemical propulsion. The use of a DSM does not significantly reduce the penalties. The results of this study can enable mission designers to incorporate the influence of off-nominal departure conditions of the interplanetary trajectory in the overall conceptual design of a Mars transfer vehicle.

  6. Effect of departure delays on manned Mars mission selection

    NASA Astrophysics Data System (ADS)

    Desai, Prasun N.; Tartabini, Paul V.

    1995-03-01

    This study determines the effect on the initial mass in low Earth orbit (IMLEO) of delaying departure from Mars and Earth by 5, 15, and 30 days, once a nominal mission to Mars has been selected. Additionally, the use of a deep-space maneuver (DSM) is considered in order to alleviate the IMLEO penalties. Three different classes of missions are analyzed, using chemical and nuclear thermal propulsion systems in the 2000-2025 time frame: opposition, conjunction, and fast-transfer conjunction. The results indicate that Mars and Earth delays can lead to large IMLEO penalties. Opposition and fast-transfer conjunction-class missions have the highest IMLEO penalties, upwards of 432.4 and 1977.3 metric tons (mt), respectively. Conjunction-class missions, on the other hand, tend to be insensitive to Mars and Earth delays, having IMLEO penalties under 103.5 mt. As expected, nuclear thermal propulsion had significantly lower IMLEO penalties than chemical propulsion. The use of a DSM does not significantly reduce the penalties. The results of this study can enable mission designers to incorporate the influence of off-nominal departure conditions of the interplanetary trajectory in the overall conceptual design of a Mars transfer vehicle.

  7. TTSA: An Effective Scheduling Approach for Delay Bounded Tasks in Hybrid Clouds.

    PubMed

    Yuan, Haitao; Bi, Jing; Tan, Wei; Zhou, MengChu; Li, Bo Hu; Li, Jianqiang

    2016-07-09

    The economy of scale provided by cloud attracts a growing number of organizations and industrial companies to deploy their applications in cloud data centers (CDCs) and to provide services to users around the world. The uncertainty of arriving tasks makes it a big challenge for private CDC to cost-effectively schedule delay bounded tasks without exceeding their delay bounds. Unlike previous studies, this paper takes into account the cost minimization problem for private CDC in hybrid clouds, where the energy price of private CDC and execution price of public clouds both show the temporal diversity. Then, this paper proposes a temporal task scheduling algorithm (TTSA) to effectively dispatch all arriving tasks to private CDC and public clouds. In each iteration of TTSA, the cost minimization problem is modeled as a mixed integer linear program and solved by a hybrid simulated-annealing particle-swarm-optimization. The experimental results demonstrate that compared with the existing methods, the optimal or suboptimal scheduling strategy produced by TTSA can efficiently increase the throughput and reduce the cost of private CDC while meeting the delay bounds of all the tasks.

  8. [Systematic review of delayed auditory feedback effectiveness for stuttering reduction].

    PubMed

    Andrade, Claudia Regina Furquim de; Juste, Fabiola Staróbole

    2011-01-01

    To perform a systematic review of studies related to the effects of delayed auditory feedback on speech fluency in individuals who stutter. Concepts of the Cochrane Handbook were followed: formulation of initial question (theme to be reviewed), location and selection of studies (PubMed database) and compatibilization among researchers (aiming to minimize possible citation losses). The following were excluded: citations in languages other than English, citations that did not allow access to full text, repeated citations due to the overlap of keywords, studies developed exclusively with fluent individuals, case reports, reviews of the literature, letters to the editor, and texts that were not directly related to the theme. Hence, texts that were related to treatment with delayed auditory feedback (DAF) and frequency-altered feedback (FAF) were analyzed. Data were analyzed according to research indicators and according to study quality markers. The results indicated that the use of altered auditory feedback devices for the reduction of stuttering events still do not have robust support for their applicability. Methodological variability does not allow a consistent answer, or a trend about the effectiveness of the device, to be drawn. Although the limitations in the studies prevent generalizations about the effectiveness of the device for the reduction of stuttering, these same limitations are important resources for future research planning.

  9. Region effects influence local tree species diversity.

    PubMed

    Ricklefs, Robert E; He, Fangliang

    2016-01-19

    Global patterns of biodiversity reflect both regional and local processes, but the relative importance of local ecological limits to species coexistence, as influenced by the physical environment, in contrast to regional processes including species production, dispersal, and extinction, is poorly understood. Failure to distinguish regional influences from local effects has been due, in part, to sampling limitations at small scales, environmental heterogeneity within local or regional samples, and incomplete geographic sampling of species. Here, we use a global dataset comprising 47 forest plots to demonstrate significant region effects on diversity, beyond the influence of local climate, which together explain more than 92% of the global variation in local forest tree species richness. Significant region effects imply that large-scale processes shaping the regional diversity of forest trees exert influence down to the local scale, where they interact with local processes to determine the number of coexisting species.

  10. Diverse expression of delayed rectifier K+ channel subtype transcripts in several types of smooth muscles of the rat.

    PubMed

    Ohya, S; Tanaka, M; Watanabe, M; Maizumi, Y

    2000-06-01

    Diverse expression of voltage dependent K+ (Kv) channels was examined in smooth muscles (SMs); carotid artery (CA), mesenteric artery (MA), urinary bladder (UB), and vas deferens (VD) of the rat, using RT-PCR based analyses. Among eight Kv channel subtypes examined (Kv 1.1, Kv 1.2, Kv 1.5, Kv 1.6, Kv 2.1, Kv 2.2, Kv 3.1, and Kv 3.2), expression of three delayed rectifier Kv (KD) channel (Kv 1.2, Kv 1.5, and Kv 2.1) transcripts was observed in these SMs. To determine precisely the expression levels of the transcripts encoding K(D) subtypes, those of three K(D) subtypes (Kv 1.2, Kv 1.5, and Kv 2.1) were determined by competitive PCR. In vascular SM tissues, CA and MA, Kv 1.2 and Kv 1.5 transcripts were expressed at relatively high levels, whereas in visceral SM tissues, UB and VD, Kv 2.1 transcripts were expressed at the relatively high levels. These results suggest that the diverse expression of K(D) subtypes is, at least in part, responsible for differences in electrical excitability and also for the variation of the electrophysiological and pharmacological phenotypes as tonic and phasic SMs.

  11. Predator Dispersal Determines the Effect of Connectivity on Prey Diversity

    PubMed Central

    Limberger, Romana; Wickham, Stephen A.

    2011-01-01

    Linking local communities to a metacommunity can positively affect diversity by enabling immigration of dispersal-limited species and maintenance of sink populations. However, connectivity can also negatively affect diversity by allowing the spread of strong competitors or predators. In a microcosm experiment with five ciliate species as prey and a copepod as an efficient generalist predator, we analysed the effect of connectivity on prey species richness in metacommunities that were either unconnected, connected for the prey, or connected for both prey and predator. Presence and absence of predator dispersal was cross-classified with low and high connectivity. The effect of connectivity on local and regional richness strongly depended on whether corridors were open for the predator. Local richness was initially positively affected by connectivity through rescue of species from stochastic extinctions. With predator dispersal, however, this positive effect soon turned negative as the predator spread over the metacommunity. Regional richness was unaffected by connectivity when local communities were connected only for the prey, while predator dispersal resulted in a pronounced decrease of regional richness. The level of connectivity influenced the speed of richness decline, with regional species extinctions being delayed for one week in weakly connected metacommunities. While connectivity enabled rescue of prey species from stochastic extinctions, deterministic extinctions due to predation were not overcome through reimmigration from predator-free refuges. Prey reimmigrating into these sink habitats appeared to be directly converted into increased predator abundance. Connectivity thus had a positive effect on the predator, even when the predator was not dispersing itself. Our study illustrates that dispersal of a species with strong negative effects on other community members shapes the dispersal-diversity relationship. When connections enable the spread of a

  12. Predator dispersal determines the effect of connectivity on prey diversity.

    PubMed

    Limberger, Romana; Wickham, Stephen A

    2011-01-01

    Linking local communities to a metacommunity can positively affect diversity by enabling immigration of dispersal-limited species and maintenance of sink populations. However, connectivity can also negatively affect diversity by allowing the spread of strong competitors or predators. In a microcosm experiment with five ciliate species as prey and a copepod as an efficient generalist predator, we analysed the effect of connectivity on prey species richness in metacommunities that were either unconnected, connected for the prey, or connected for both prey and predator. Presence and absence of predator dispersal was cross-classified with low and high connectivity. The effect of connectivity on local and regional richness strongly depended on whether corridors were open for the predator. Local richness was initially positively affected by connectivity through rescue of species from stochastic extinctions. With predator dispersal, however, this positive effect soon turned negative as the predator spread over the metacommunity. Regional richness was unaffected by connectivity when local communities were connected only for the prey, while predator dispersal resulted in a pronounced decrease of regional richness. The level of connectivity influenced the speed of richness decline, with regional species extinctions being delayed for one week in weakly connected metacommunities. While connectivity enabled rescue of prey species from stochastic extinctions, deterministic extinctions due to predation were not overcome through reimmigration from predator-free refuges. Prey reimmigrating into these sink habitats appeared to be directly converted into increased predator abundance. Connectivity thus had a positive effect on the predator, even when the predator was not dispersing itself. Our study illustrates that dispersal of a species with strong negative effects on other community members shapes the dispersal-diversity relationship. When connections enable the spread of a

  13. Effect of Time Delay on Recognition Memory for Pictures: The Modulatory Role of Emotion

    PubMed Central

    Wang, Bo

    2014-01-01

    This study investigated the modulatory role of emotion in the effect of time delay on recognition memory for pictures. Participants viewed neutral, positive and negative pictures, and took a recognition memory test 5 minutes, 24 hours, or 1 week after learning. The findings are: 1) For neutral, positive and negative pictures, overall recognition accuracy in the 5-min delay did not significantly differ from that in the 24-h delay. For neutral and positive pictures, overall recognition accuracy in the 1-week delay was lower than in the 24-h delay; for negative pictures, overall recognition in the 24-h and 1-week delay did not significantly differ. Therefore negative emotion modulates the effect of time delay on recognition memory, maintaining retention of overall recognition accuracy only within a certain frame of time. 2) For the three types of pictures, recollection and familiarity in the 5-min delay did not significantly differ from that in the 24-h and the 1-week delay. Thus emotion does not appear to modulate the effect of time delay on recollection and familiarity. However, recollection in the 24-h delay was higher than in the 1-week delay, whereas familiarity in the 24-h delay was lower than in the 1-week delay. PMID:24971457

  14. Effect of time delay on recognition memory for pictures: the modulatory role of emotion.

    PubMed

    Wang, Bo

    2014-01-01

    This study investigated the modulatory role of emotion in the effect of time delay on recognition memory for pictures. Participants viewed neutral, positive and negative pictures, and took a recognition memory test 5 minutes, 24 hours, or 1 week after learning. The findings are: 1) For neutral, positive and negative pictures, overall recognition accuracy in the 5-min delay did not significantly differ from that in the 24-h delay. For neutral and positive pictures, overall recognition accuracy in the 1-week delay was lower than in the 24-h delay; for negative pictures, overall recognition in the 24-h and 1-week delay did not significantly differ. Therefore negative emotion modulates the effect of time delay on recognition memory, maintaining retention of overall recognition accuracy only within a certain frame of time. 2) For the three types of pictures, recollection and familiarity in the 5-min delay did not significantly differ from that in the 24-h and the 1-week delay. Thus emotion does not appear to modulate the effect of time delay on recollection and familiarity. However, recollection in the 24-h delay was higher than in the 1-week delay, whereas familiarity in the 24-h delay was lower than in the 1-week delay.

  15. Effects of alveolar ridge preservation on delayed implant osseointegration

    PubMed Central

    Shao, Shan; Li, Bin; Xue, Hui-Min; Huang, Hai-Yun; Liu, Gang-Li

    2015-01-01

    To evaluate the effects of alveolar ridge preservation with Bio-Oss bone substitute (Geistlich Pharma) on delayed implant osseointegration. The 3rd and 4th left and right mandibular premolars were extracted from four adult healthy male and female dogs. For the experimental group, we randomly selected two extraction sockets in each dog to be filled with Bio-Oss bone substitute (Geistlich Pharma). The two remaining extraction sockets remained untreated and served as the control group. Three months after Bio-Oss placement, dental implants were inserted into the alveolar bone of the experimental group and the control group. The osteogenic activity of the bone around the implants was assessed by evaluating the histological morphology and by estimating histomorphometric parameters at 3 and 6 months after delayed implantation. At 3 months, Goldner’s trichrome staining analysis showed that the bone-implant contact rate and mineralised bone area around the implant were significantly higher in the experimental group (75.98% ± 8.97% and 69.52% ± 9.63%, respectively) than in the control group (56.13% ± 8.18% and 52.82% ± 7.25%, respectively; P < 0.05). However, at 6 months, the two groups showed no significant difference. Fluorescence microscopy analysis revealed that the average mineralisation apposition rate of the bone tissue around the dental implant in the experimental group at 3 and 6 months was 6.80 ± 0.43 μm and 8.38 ± 0.84 μm, respectively, which was significantly higher than the rate in the control group (P < 0.05). These data indicated that alveolar ridge preservation by using Bio-Oss placement can promote osseointegration of delayed implantation. This may be a promising option for clinical use. PMID:26379871

  16. Isolating Behavioral Mechanisms of Inter-Temporal Choice: Nicotine Effects on Delay Discounting and Amount Sensitivity

    ERIC Educational Resources Information Center

    Locey, Matthew L.; Dallery, Jesse

    2009-01-01

    Many drugs of abuse produce changes in impulsive choice, that is, choice for a smaller-sooner reinforcer over a larger-later reinforcer. Because the alternatives differ in both delay and amount, it is not clear whether these drug effects are due to the differences in reinforcer delay or amount. To isolate the effects of delay, we used a titrating…

  17. A study of the effect of group delay distortion on an SMSK satellite communications channel

    NASA Technical Reports Server (NTRS)

    Kerczewski, Robert J.

    1987-01-01

    The effects of group delay distortion on an SMSK satellite communications channel have been investigated. Software and hardware simulations have been used to determine the effects of channel group delay variations with frequency on the bit error rate for a 220 Mbps SMSK channel. These simulations indicate that group delay distortions can significantly degrade the bit error rate performance. The severity of the degradation is dependent on the amount, type, and spectral location of the group delay distortion.

  18. Multitrophic diversity effects of network degradation.

    PubMed

    Nichols, Elizabeth; Peres, Carlos A; Hawes, Joseph E; Naeem, Shahid

    2016-07-01

    Predicting the functional consequences of biodiversity loss in realistic, multitrophic communities remains a challenge. No existing biodiversity-ecosystem function study to date has simultaneously incorporated information on species traits, network topology, and extinction across multiple trophic levels, while all three factors are independently understood as critical drivers of post-extinction network structure and function. We fill this gap by comparing the functional consequences of simulated species loss both within (monotrophic) and across (bitrophic) trophic levels, in an ecological interaction network estimated from spatially explicit field data on tropical fecal detritus producer and consumers (mammals and dung beetles). We simulated trait-ordered beetle and mammal extinction separately (monotrophic extinction) and the coextinction of beetles following mammal loss (bitrophic extinction), according to network structure. We also compared the diversity effects of bitrophic extinction models using a standard monotrophic function (the daily production or consumption of fecal detritus) and a unique bitrophic functional metric (the proportion of daily detritus production that is consumed). We found similar mono- and bitrophic diversity effects, regardless of which species traits were used to drive extinctions, yet divergent predictions when different measures of function were used. The inclusion of information on network structure had little apparent effect on the qualitative relationship between diversity and function. These results contribute to our growing understanding of the functional consequences of biodiversity from real systems and underscore the importance of species traits and realistic functional metrics to assessments of the ecosystem impacts of network degradation through species loss.

  19. Effects of restraint on expansion due to delayed ettringite formation

    SciTech Connect

    Bouzabata, Hassina; Multon, Stephane; Sellier, Alain; Houari, Hacene

    2012-07-15

    Delayed ettringite formation (DEF) is a chemical reaction that causes expansion in civil engineering structures. The safety level of such damaged structures has to be reassessed. To do this, the mechanical conditions acting on DEF expansions have to be analysed and, in particular, the variation of strength with expansion and the effect of restraint on the DEF expansion. This paper highlights several points: DEF expansion is isotropic in stress-free conditions, compressive stresses decrease DEF expansion in the direction subjected to restraint and lead to cracks parallel to the restraint, and expansion measured in the stress-free direction of restrained specimens is not modified. Thus restraint causes a decrease of the volumetric expansion and DEF expansion under restraint is anisotropic. Moreover, the paper examines the correlation between DEF expansion and concrete damage, providing data that can be used for the quantification of the effect of stresses on DEF induced expansion.

  20. Delayed effects of ionizing radiation on the ear

    SciTech Connect

    Bohne, B.A.; Marks, J.E.; Glasgow, G.P.

    1985-07-01

    The question of damage to the ear from exposure to ionizing radiation was addressed by exposing groups of chinchillas to fractioned doses of radiation (2 Gy per day) for total doses ranging from 40 to 90 Gy. In order to allow any delayed effects of radiation to become manifest, the animals were sacrificed two years after completion of treatment and their temporal bones were prepared for microscopic examination. The most pronounced effect of treatment was degeneration of sensory and supporting cells and loss of eighth nerve fibers in the organ of Corti. Damage increased with increasing dose of radiation. The degree of damage found in many of these ears was of sufficient magnitude to produce a permanent sensorineural hearing loss.

  1. Clinical Effects of Gemifloxacin on the Delay of Tuberculosis Treatment

    PubMed Central

    Kim, Seo Yun; Yim, Jae-Joon; Park, Jong Sun; Park, Sung Soo; Heo, Eun Young; Lee, Chang-Hoon; Chung, Hee Soon

    2013-01-01

    Although gemifloxacin has low in vitro activity against Mycobacterium tuberculosis, the effect of gemifloxacin on the delay of tuberculosis (TB) treatment has not been validated in a clinical setting. The study group included patients with culture-confirmed pulmonary TB who initially received gemifloxacin for suspected community-acquired pneumonia (CAP). Two control groups contained patients treated with other fluoroquinolones or nonfluoroquinolone antibiotics. Sixteen cases were treated with gemifloxacin for suspected CAP before TB diagnosis. Sixteen and 32 patients were treated with other fluoroquinolones and nonfluoroquinolones, respectively. The median period from the initiation of antibiotics to the administration of anti-TB medication was nine days in the gemifloxacin group, which was significantly different from the other fluoroquinolones group (35 days). The median times for the nonfluoroquinolone group and the gemifloxacin group were not significantly different. There were no significant differences between the gemifloxacin and other fluoroquinolone group in terms of symptomatic and radiographic improvements. However, the frequency of radiographic improvement in the other fluoroquinolones group tended to be higher than in the gemifloxacin group. Gemifloxacin might be the preferred fluoroquinolone for treating CAP, to alleviate any concerns about delaying TB treatment. PMID:23486643

  2. Clinical effects of gemifloxacin on the delay of tuberculosis treatment.

    PubMed

    Kim, Seo Yun; Yim, Jae-Joon; Park, Jong Sun; Park, Sung Soo; Heo, Eun Young; Lee, Chang-Hoon; Chung, Hee Soon; Kim, Deog Kyeom

    2013-03-01

    Although gemifloxacin has low in vitro activity against Mycobacterium tuberculosis, the effect of gemifloxacin on the delay of tuberculosis (TB) treatment has not been validated in a clinical setting. The study group included patients with culture-confirmed pulmonary TB who initially received gemifloxacin for suspected community-acquired pneumonia (CAP). Two control groups contained patients treated with other fluoroquinolones or nonfluoroquinolone antibiotics. Sixteen cases were treated with gemifloxacin for suspected CAP before TB diagnosis. Sixteen and 32 patients were treated with other fluoroquinolones and nonfluoroquinolones, respectively. The median period from the initiation of antibiotics to the administration of anti-TB medication was nine days in the gemifloxacin group, which was significantly different from the other fluoroquinolones group (35 days). The median times for the nonfluoroquinolone group and the gemifloxacin group were not significantly different. There were no significant differences between the gemifloxacin and other fluoroquinolone group in terms of symptomatic and radiographic improvements. However, the frequency of radiographic improvement in the other fluoroquinolones group tended to be higher than in the gemifloxacin group. Gemifloxacin might be the preferred fluoroquinolone for treating CAP, to alleviate any concerns about delaying TB treatment.

  3. Contagion effects in a chartist fundamentalist model with time delays

    NASA Astrophysics Data System (ADS)

    Dibeh, Ghassan

    2007-08-01

    In this paper two models of speculative markets are developed to study the effects of feedback mechanisms in financial markets. In the first model, a crash market model couples a linear chartist-fundamentalist model with time delays with a log-periodic market index I(t) through direct coupling. Numerical solutions to the model show that asset prices exhibit significant persistence as a result of the coupling to the log-periodic market index. An extension to include endogenous wealth dynamics shows that the chartists benefit from the persistent dynamics induced by the coupling. The second model is a two-asset model represented by a 2-dimensional delay-differential equation. Asset one price exhibits limit cycle dynamics while in the second market asset prices follow stable damped oscillations. The markets are coupled through a diffusive coupling term. Solutions to the coupled model show that the dynamics of asset two changes fundamentally with the price now exhibiting a limit cycle. The stable converging dynamics is replaced with limit cycle oscillations around the fundamental.

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

    NASA Astrophysics Data System (ADS)

    Ohnishi, Hitoshi; Mochizuki, Kaname

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

  5. Effect of caffeine on radiation-induced mitotic delay: delayed expression of G/sub 2/ arrest

    SciTech Connect

    Rowley, R.; Zorch, M.; Leeper, D.B.

    1984-01-01

    In the presence of 5 mM caffeine, irradiated (1.5 Gy) S and G/sub 2/ cells progressed to mitosis in register and without arrest in G/sub 2/. Caffeine (5 mM) markedly reduced mitotic delay even after radiation doses up to 20 Gy. When caffeine was removed from irradiated (1.5 Gy) and caffeine-treated cells, a period of G/sub 2/ arrest followed, similar in length to that produced by radiation alone. The arrest expressed was independent of the duration of the caffeine treatment for exposures up to 3 hr. The similarity of the response to the cited effects of caffeine on S-phase delay suggests a common basis for delay induction in S and G/sub 2/ phases.

  6. The effect of different distractions on remembering delayed intentions.

    PubMed

    Schaper, Philipp; Grundgeiger, Tobias

    2017-06-13

    In safety-critical domains, frequently intentions need to be delayed until an ongoing task is completed. Research using the delay-execute paradigm showed that interruptions during the delay cause forgetting. However, staff members often handle an initial distraction not by interrupting the ongoing task but by acknowledging the distraction or multitasking. In Experiments 1a and 1b, we observed that, compared to a no distraction condition, multitasking significantly decreased remembering of intentions and interrupting decreased remembering even further. In Experiment 2, interruptions with context change reduced remembering of intentions compared to uninterrupted delays, and at the same time, interruptions without context change improved memory performance compared to uninterrupted delays. However, improved memory performance resulted in decreased interrupting task performance. Theoretically, the results support the contextual cueing mechanism of delay-execute tasks. Considering safety-critical domains, multitasking, interruptions and context changes can contribute to forgetting of tasks.

  7. Understanding the delayed-keyword effect on metacomprehension accuracy.

    PubMed

    Thiede, Keith W; Dunlosky, John; Griffin, Thomas D; Wiley, Jennifer

    2005-11-01

    The typical finding from research on metacomprehension is that accuracy is quite low. However, recent studies have shown robust accuracy improvements when judgments follow certain generation tasks (summarizing or keyword listing) but only when these tasks are performed at a delay rather than immediately after reading (K. W. Thiede & M. C. M. Anderson, 2003; K. W. Thiede, M. C. M. Anderson, & D. Therriault, 2003). The delayed and immediate conditions in these studies confounded the delay between reading and generation tasks with other task lags, including the lag between multiple generation tasks and the lag between generation tasks and judgments. The first 2 experiments disentangle these confounded manipulations and provide clear evidence that the delay between reading and keyword generation is the only lag critical to improving metacomprehension accuracy. The 3rd and 4th experiments show that not all delayed tasks produce improvements and suggest that delayed generative tasks provide necessary diagnostic cues about comprehension for improving metacomprehension accuracy.

  8. Gestational Trophoblastic Disease Diagnosis Delayed by the Hook Effect.

    PubMed

    Cormano, Julia; Mackay, Gillian; Holschneider, Christine

    2015-10-01

    A "hook effect" resulting from saturation of antibodies used in pregnancy tests can occur at human chorionic gonadotropin (hCG) levels above 500,000 milliinternational units/mL, resulting in falsely negative values. A 34-year-old woman, gravida 5 para 3, presented to the emergency department after heavy bleeding. Ultrasonogram revealed a uterine mass, urine pregnancy test result was negative, and endometrial biopsy inconclusive. The patient was discharged and presented 10 days later with recurrent bleeding. Urine pregnancy test result was again negative, but serum hCG was 581 milliinternational units/mL. Serial dilution revealed an actual hCG higher than 5 million milliinternational units/mL. She was diagnosed with gestational trophoblastic disease. Awareness of the risk of a false-negative pregnancy test result when hCG levels are extremely high may prevent delayed diagnosis of gestational trophoblastic disease.

  9. Effect of Pressure on Piloted Ignition Delay of PMMA

    NASA Technical Reports Server (NTRS)

    McAllister, Sara; Lai, Janice; Scott, Sarah; Ramirez-Correa, Amelia; Fernandez-Pello, Carlos; Urban, David; Ruff, Gary

    2008-01-01

    In order to reduce the risk of decompression sickness associated with spacewalks, NASA is considering designing the next generation of exploration vehicles and habitats with a different cabin environment than used previously. The proposed environment uses a total cabin pressure of 52.7 to 58.6 kPa with an oxygen concentration of 30 to 34% by volume and was chosen with material flammability in mind. Because materials may burn differently under these conditions and there is little information on how this new environment affects the flammability of the materials onboard, it is important to conduct material flammability experiments at the intended exploration atmosphere. One method to evaluate material flammability is by its ease of ignition. To this end, piloted ignition delay tests were conducted in the Forced Ignition and Spread Test (FIST) apparatus subject to this new environment. In these tests, polymethylmethacylate (PMMA) was exposed to a range of oxidizer flow velocities and externally applied heat fluxes. The ultimate goal is to determine the individual effect of pressure and the combined effect of pressure and oxygen concentration on the ignition delay. Tests were conducted for a baseline case of normal pressure and oxygen concentration, low pressure (58.6 kPa) with normal oxygen (21%). Future work will focus on low pressure with 32% oxygen concentration (space exploration atmosphere - SEA) conditions. It was found that reducing the pressure while keeping the oxygen concentration at 21% reduced the ignition time by 17% on average. It was also noted that the critical heat flux for ignition decreases in low-pressure conditions. Because tests conducted in standard atmospheric conditions will underpredict the flammability of materials intended for use on spacecraft, fire safety onboard at exploration atmospheres may be compromised.

  10. Viva Delay.

    PubMed

    Yahaghi, Hossein; Sorooshian, Shahryar; Yahaghi, Javad

    2016-06-28

    The time delay between submission of a thesis and Viva Voce is intolerable for students. This letter tries to draw the readers' attention to the effect of choosing the right examiner, in order to reduce the Viva Voce delay.

  11. The effects of delayed auditory and visual feedback on speech production

    PubMed Central

    Chesters, Jennifer; Baghai-Ravary, Ladan; Möttönen, Riikka

    2015-01-01

    Monitoring the sensory consequences of articulatory movements supports speaking. For example, delaying auditory feedback of a speakers’ voice disrupts speech production. Also, there is evidence that this disruption may be decreased by immediate visual feedback, i.e., seeing one’s own articulatory movements. It is, however, unknown whether delayed visual feedback affects speech production in fluent speakers. Here, the effects of delayed auditory and visual feedback on speech fluency (i.e., speech rate and errors), vocal control (i.e., intensity and pitch) and speech rhythm were investigated. Participants received delayed (by 200 ms) or immediate auditory feedback, whilst repeating sentences. Moreover, they received either no visual feedback, immediate visual feedback or delayed visual feedback (by 200, 400 and 600 ms). Delayed auditory feedback affected fluency, vocal control and rhythm. Immediate visual feedback had no effect on any of the speech measures when it was combined with delayed auditory feedback. Delayed visual feedback did, however, affect speech fluency when it was combined with delayed auditory feedback. In sum, the findings show that delayed auditory feedback disrupts fluency, vocal control and rhythm and that delayed visual feedback can strengthen the disruptive effect of delayed auditory feedback on fluency. PMID:25698020

  12. Type Ia supernova diversity: white dwarf central density as a secondary parameter in three-dimensional delayed detonation models

    NASA Astrophysics Data System (ADS)

    Seitenzahl, I. R.; Ciaraldi-Schoolmann, F.; Röpke, F. K.

    2011-07-01

    Delayed detonations of Chandrasekhar mass white dwarfs (WDs) have been very successful in explaining the spectra, light curves and the width-luminosity relation of spectroscopically normal Type Ia supernovae (SNe Ia). The ignition of the thermonuclear deflagration flame at the end of the convective carbon 'simmering' phase in the core of the WD is still not well understood, and much about the ignition kernel distribution remains unknown. Furthermore, the central density at the time of ignition depends on the still uncertain screened carbon fusion reaction rates, the accretion history and cooling time of the progenitor, and the composition. We present the results of 12 high-resolution three-dimensional delayed detonation SN Ia explosion simulations that employ a new criterion to trigger the deflagration to detonation transition (DDT). The simulations fall into three ignition categories: relatively bright SNe with five ignition kernels and a weak deflagration phase (three different central densities); relatively dim SNe with 1600 ignition kernels and a strong deflagration phase (three different central densities) and intermediate SNe with 200 ignition kernels (six different central densities). All simulations trigger our DDT criterion and the resulting delayed detonations unbind the star. We find a trend of increasing iron group element (IGE) production with increasing central density for all three categories. The total 56Ni yield, however, remains more or less constant, even though increased electron captures at high density result in a decreasing 56Ni mass fraction of the IGE material. We attribute this to an approximate balance of 56Ni producing and destroying effects. The deflagrations that were ignited at higher density initially have a faster growth rate of subgrid-scale turbulence. Hence, the effective flame speed increases faster, which triggers the DDT criterion earlier, at a time when the central density of the expanded star is higher. This leads to an

  13. Effects of time delay on stochastic resonance of the stock prices in financial system

    NASA Astrophysics Data System (ADS)

    Li, Jiang-Cheng; Li, Chun; Mei, Dong-Cheng

    2014-06-01

    The effect of time delay on stochastic resonance of the stock prices in finance system was investigated. The time delay is introduced into the Heston model driven by the extrinsic and intrinsic periodic information for stock price. The signal power amplification (SPA) was calculated by numerical simulation. The results indicate that an optimal critical value of delay time maximally enhances the reverse-resonance in the behaviors of SPA as a function of long-run variance of volatility or cross correlation coefficient between noises for both cases of intrinsic and extrinsic periodic information. Moreover, in both cases, being a critical value in the delay time, when the delay time takes value below the critical value, reverse-resonance increases with the delay time increasing, however, when the delay time takes value above the critical value, the reverse-resonance decrease with the delay time increasing.

  14. On the delay effects of different channels in Internet-based networked control systems

    NASA Astrophysics Data System (ADS)

    Zhao, Yun-Bo; Kim, Jongrae; Sun, Xi-Ming; Liu, Guo-Ping

    2013-11-01

    The sensor-to-controller and the controller-to-actuator delays in networked control systems (NCSs) are investigated for the first time with respect to their different effects on the system performance. This study starts with identifying the delay-independent and delay-dependent control laws in NCSs, and confirms that only two delay-dependent control laws can cause different delay effects in different channels. The conditions under which the different delays in different channels can cause different effects are then given for both delay-dependent control laws. The results are verified by numerical examples. Potentially, these results can be regarded as important design principles in the practical implementation of NCSs.

  15. Delayed effects of external radiation exposure: a brief history.

    PubMed

    Miller, R W

    1995-11-01

    Within months of Roentgen's discovery of X rays, severe adverse effects were reported, but not well publicized. As a result, over the next two decades, fluoroscope operators suffered lethal skin carcinomas. Later, case reports appeared concerning leukemia in radiation workers, and infants born with severe mental retardation after their mothers had been given pelvic radiotherapy early in pregnancy. Fluoroscopy and radiotherapy for benign disorders continued to be used with abandon until authoritative reports were published on the adverse effects of ionizing radiation by the U.S. NAS-NRC and the UK MRC in 1956. Meanwhile, exposure to the atomic bombs in Japan had occurred and epidemics of delayed effects began to be recognized among the survivors: cataracts (1949), leukemia (1952) and severe mental retardation among newborn infants after intrauterine exposure (1952). No statistically significant excess of germ-cell genetic effects was detected by six clinical measurements (1956), the F1 mortality (1981), cytogenetic studies (1987) or biochemical genetic studies (1988). Somatic cell effects were revealed by long-lasting chromosomal aberrations in peripheral lymphocytes (1968), and somatic cell mutations were found at the glycophorin A locus in erythrocytes (1992). Molecular biology is a likely focus of new studies based on the function of the gene for ataxia telangiectasia (1995), a disorder in which children have severe, even lethal acute radiation reactions when given conventional doses of radiotherapy for lymphoma, to which they are prone. Also, obligate heterozygote female relatives can be studied for increased susceptibility to radiation-induced breast cancer, as suggested by clinical studies. The tumor registries in Hiroshima and Nagasaki now provide incidence data that show the extent of increases in eight common cancers and no increase in eight others (1994). The possibility of very late effects of A-bomb exposure is suggested by recent reports of increased

  16. Delayed effects of external radiation exposure: A brief history

    SciTech Connect

    Miller, R.W.

    1995-11-01

    Within months of Roentgen`s discovery of X rays, severe adverse effects were reported, but not well publicized. As a result, over the next two decades, fluoroscope operators suffered lethal skin carcinomas. Later, case reports appeared concerning leukemia in radiation workers, and infants born with severe mental retardation after their mothers had been given pelvic radiotherapy early in pregnancy. Fluoroscopy and radiotherapy for benign disorders continued to be used with abandon until authoritative reports were published on the adverse effects of ionizing radiation by the U.S. NAS-NRC and the UK MRC in 1956. Meanwhile, exposure to the atomic bombs in Japan had occurred and epidemics of delayed effects began to be recognized among the survivors: cataracts, leukemia and severe mental retardation among newborn infants after intra-uterine exposure. No statistically significant excess of germ-cell genetic effects was detected by six clinical measurements, the F{sub 1} mortality, cytogenetic studies or biochemical genetic studies. Somatic cell effects were revealed by long-lasting chromosomal aberrations in peripheral lymphocytes, and somatic cell mutations were found at the glycophorin A locus in erythrocytes. Molecular biology is a likely focus of new studies based on the function of the gene for ataxia telangiectasia, a disorder in which children have severe, even lethal acute radiation reactions when given conventional doses of radiotherapy for lymphoma, to which they are prone. The tumor registries in Hiroshima and Nagasaki now provide incidence data that show the extent of increases in eight common cancers and no increase in eight others. The possibility of very late effects of A-bomb exposure is suggested by recent reports of increased frequencies of hyperparathyroidism, parathyroid cancers and certain causes of death other than cancer. 88 refs., 1 fig.

  17. Discounting of delayed hypothetical money and food: effects of amount.

    PubMed

    Odum, Amy L; Baumann, Ana A L; Rimington, Delores D

    2006-11-01

    Delay discounting research determines how the value of an outcome is affected by delay to its receipt. Research so far shows that consumable outcomes are discounted more steeply by delay than money. Prior studies, however, have used large amounts of the outcomes (e.g. 100 dollars worth) that would not typically be consumed in one bout, unlike the corresponding amount of money (e.g. 100 dollars ). This experiment examined whether small amounts of food would be discounted more steeply than money, as occurs with larger amounts. One hundred and two adults indicated their preferences in a series of choices for two hypothetical outcome types: immediate versus delayed food and immediate versus delayed money. Participants made choices involving either relatively small maximum amounts of food (10 dollars worth) and money (10 dollars) or for relatively large maximum amounts of food (100 dollars worth) and money (100 dollars ). In the within-subject comparisons, food was discounted more steeply by delay than money for both groups. In the between-subject comparisons, different amounts of the commodities were affected similarly by delay. Overall, these results suggest that steeper discounting of consumable outcomes than money is a fairly robust phenomenon, occurring with relatively small amounts of outcomes as well as with larger amounts.

  18. Effects of Acute and Chronic Morphine on Delay Discounting in Pigeons

    PubMed Central

    Eppolito, Amy K.; France, Charles P.; Gerak, Lisa R.

    2015-01-01

    When reinforcers of different magnitudes are concurrently available, choice is greater for a large reinforcer; that choice can be reduced by delaying its delivery, a phenomenon called delay discounting and represented graphically by a delay curve in which choice is plotted as a function of delay to the large reinforcer. Morphine, administered acutely, can alter responding for large, delayed reinforcers. In this study, the impact of morphine tolerance, dependence and withdrawal on choice of delayed reinforcers was examined in 6 pigeons responding to receive a small amount of food delivered immediately or a larger amount delivered immediately or after delays that increased within sessions. Acutely, morphine decreased responding for the large reinforcer, and the effect was greater when morphine was administered immediately, rather than 6 hr, before sessions. During 8 weeks of daily administration, morphine produced differential effects across pigeons, shifting the delay curve downward in some and upward in others. In all pigeons, tolerance developed to the response rate-decreasing effects of morphine but not to its effects on delay discounting. When chronic morphine treatment was discontinued, rate of responding decreased in 4 pigeons, indicating the emergence of withdrawal; choice of the large reinforcer increased, regardless of delay, in all pigeons, an effect that persisted for weeks. These data suggest that chronic morphine administration has long-lasting effects on choice behavior, which might impact vulnerability to relapse in opioid abusers. PMID:23553726

  19. The effect of time-delayed feedback on logical stochastic resonance

    NASA Astrophysics Data System (ADS)

    Wang, Nan; Song, Aiguo; Yang, Biao

    2017-06-01

    We examine the possibility of obtaining logic operation in a quartic-bistable system with linear time-delayed feedback subjected to Gaussian noise. The effect of time-delayed feedback on the effective potential well is investigated, and explicit numerical stimulation is conducted to study the influence of delay time and strength of the time-delayed feedback on the responses of the system. Although the response deteriorates slightly at low values of noise intensity with time-delayed feedback and the peak correct probability decreases from 100% when the delay time is too long, the reliability of obtaining the desired logic output is enhanced in the higher noise boundary with the help of moderate time-delayed feedback. We also found that increasing the linear factor of the system can shift the optimal noise intensity to a higher level.

  20. Experiments and analysis for a controlled mechanical absorber considering delay effect

    NASA Astrophysics Data System (ADS)

    Sun, Yixia; Xu, Jian

    2015-03-01

    It is well known that a traditional passive absorber is highly effective within a narrow frequency band. To solve this problem, a time-delayed absorber is utilized to suppress the vibration of the primary system when the passive absorber loses efficiency. A controllable mechanical device is designed and constructed to implement the time-delayed feedback control. The time delay mainly comes from signal acquiring and processing, computing and applying the control force. Such delay is inherent and non-ignorable. To begin with, a mathematical model with the inherent delay is proposed to provide an analytical fundamental. Then, the value of the inherent time delay is identified by the hammer test. Experimental and numerical results show that reasonable feedback gains can significantly improve the absorber's effectiveness when the excitation frequency is close to the second resonant frequency of the new coupled system. This research provides instructive ideas to the application of the time-delayed absorber in practical engineering.

  1. Effect of delayed aging on mechanical properties of an Al-Cu-Mg alloy

    SciTech Connect

    Ravindranathan, S.P.; Kashyap, K.T.; Kumar, S.R.; Ramachandra, C.; Chatterji, B.

    2000-02-01

    The effect of delayed aging on mechanical properties is characteristically found in Al-Mg-Si alloys. Delayed aging refers to the time elapsed between solutionizing and artificial aging. Delayed aging leads to inferior properties. This effect was investigated in an Al-Cu-Mg alloy (AU2GN) of nominal composition Al-2Cu-1.5Mg-1Fe-1Ni as a function of delay. This alloy also showed a drop in mechanical properties with delay. The results are explained on the basis of Pashley's kinetic model to qualitatively explain the evolution of a coarse precipitate structure with delay. It is found that all the results of delayed aging in the Al-Cu-Mg alloys are similar to those found in Al-Mg-Si alloys.

  2. The effect of distributed time-delays on the synchronization of neuronal networks

    NASA Astrophysics Data System (ADS)

    Kachhvah, Ajay Deep

    2017-01-01

    Here we investigate the synchronization of networks of FitzHugh-Nagumo neurons coupled in scale-free, small-world and random topologies, in the presence of distributed time delays in the coupling of neurons. We explore how the synchronization transition is affected when the time delays in the interactions between pairs of interacting neurons are non-uniform. We find that the presence of distributed time-delays does not change the behavior of the synchronization transition significantly, vis-a-vis networks with constant time-delay, where the value of the constant time-delay is the mean of the distributed delays. We also notice that a normal distribution of delays gives rise to a transition at marginally lower coupling strengths, vis-a-vis uniformly distributed delays. These trends hold across classes of networks and for varying standard deviations of the delay distribution, indicating the generality of these results. So we conclude that distributed delays, which may be typically expected in real-world situations, do not have a notable effect on synchronization. This allows results obtained with constant delays to remain relevant even in the case of randomly distributed delays.

  3. The effect of caffeine ingestion on delayed onset muscle soreness.

    PubMed

    Hurley, Caitlin F; Hatfield, Disa L; Riebe, Deborah A

    2013-11-01

    The beneficial effects of caffeine on aerobic activity and resistance training performance are well documented. However, less is known concerning caffeine's potential role in reducing perception of pain and soreness during exercise. In addition, there is no information regarding the effects of caffeine on delayed onset muscle soreness (DOMS). The primary purpose of this study was to examine the effect of caffeine ingestion on muscle soreness, blood enzyme activity, and performance after a bout of elbow flexion/extension exercise. Nine low-caffeine-consuming males (body mass: 76.68 ± 8.13 kg; height: 179.18 ± 9.35 cm; age: 20 ± 1 year) were randomly assigned to ingest either caffeine or placebo 1 hour before completing 4 sets of 10 bicep curls on a preacher bench, followed by a fifth set in which subjects completed as many repetitions as possible. Soreness and soreness on palpation intensity were measured using three 0-10 visual analog scales before exercise, and 24, 48, 72, 96, and 120 hours after exercise. After a washout period, subjects crossed over to the other treatment group. Caffeine ingestion resulted in significantly (p ≤ 0.05) lower levels of soreness on day 2 and day 3 compared with placebo. Total repetitions in the final set of exercise increased with caffeine ingestion compared with placebo. This study demonstrates that caffeine ingestion immediately before an upper-body resistance training out enhances performance. A further beneficial effect of sustained caffeine ingestion in the days after the exercise bout is an attenuation of DOMS. This decreased perception of soreness in the days after a strenuous resistance training workout may allow individuals to increase the number of training sessions in a given time period.

  4. Disturbance effects on species diversity and functional diversity in riparian and upland plant communities.

    PubMed

    Biswas, Shekhar R; Mallik, Azim U

    2010-01-01

    Understanding disturbance effects on species diversity and functional diversity is fundamental to conservation planning but remains elusive. We quantified species richness, diversity, and evenness and functional richness, diversity, and evenness of riparian and upland plants along 24 small streams subjected to a range of anthropogenic disturbances in the boreal forest of northwestern Ontario, Canada. We included a total of 36 functional traits related to productivity, competitive ability, reproduction, disturbance tolerance, life history, and tolerance to habitat instability. Using nested ANOVA, we examined the response of diversity indices to disturbance and whether it followed the intermediate disturbance hypothesis (IDH) and varied with habitat stability. We found that, like species richness and diversity, functional richness and diversity reached peaks at moderate disturbance intensity; functional diversity followed the predictions of the IDH. Second, disturbance-habitat-stability coupling has very little effect on overall species and functional diversity, but the effect on particular life forms and functions may be significant. Since species richness and diversity patterns are context and system dependent, our findings should be most applicable to similar temperate riparian systems.

  5. Effect of delayed cord clamping on very preterm infants.

    PubMed

    Chiruvolu, Arpitha; Tolia, Veeral N; Qin, Huanying; Stone, Genna Leal; Rich, Diana; Conant, Rhoda J; Inzer, Robert W

    2015-11-01

    Despite significant proposed benefits, delayed umbilical cord clamping (DCC) is not practiced widely in preterm infants largely because of the question of feasibility of the procedure and uncertainty regarding the magnitude of the reported benefits, especially intraventricular hemorrhage (IVH) vs the adverse consequences of delaying the neonatal resuscitation. The objective of this study was to determine whether implementation of the protocol-driven DCC process in our institution would reduce the incidence of IVH in very preterm infants without adverse consequences. We implemented a quality improvement process for DCC the started in August 2013 in infants born at ≤32 weeks' gestational age. Eligible infants were left attached to the placenta for 45 seconds after birth. Neonatal process and outcome data were collected until discharge. We compared infants who received DCC who were born between August 2013 and August 2014 with a historic cohort of infants who were born between August 2012 and August 2013, who were eligible to receive DCC, but whose cord was clamped immediately after birth, because they were born before the protocol implementation. DCC was performed on all the 60 eligible infants; 88 infants were identified as historic control subjects. Gestational age, birthweight, and other demographic variables were similar between both groups. There were no differences in Apgar scores or admission temperature, but significantly fewer infants in the DCC cohort were intubated in delivery room, had respiratory distress syndrome, or received red blood cell transfusions in the first week of life compared with the historic cohort. A significant reduction was noted in the incidence of IVH in the DCC cohort compared with the historic control group (18.3% vs 35.2%). After adjustment for gestational age, an association was found between the incidence of IVH and DCC with IVH was significantly lower in the DCC cohort compared with the historic cohort; an odds ratio of 0

  6. Predicting Hunger: The Effects of Appetite and Delay on Choice.

    PubMed

    Read; van Leeuwen B

    1998-11-01

    Preferences often fluctuate as a result of transient changes in hunger and other visceral states. When current decisions have delayed consequences, the preferences that should be relevant are those that will prevail when the consequences occur. However, consistent with the notion of an intrapersonal empathy gap (Loewenstein, 1996) we find that an individual's current state of appetite has a significant effect on choices that apply to the future. Participants in our study made advance choices between healthy and unhealthy snacks (i.e., fruit and junk food) that they would receive in 1 week when they were either hungry (late in the afternoon) or satisfied (immediately after lunch). In 1 week, at the appointed time, they made an immediate choice, an opportunity to change their advance choice. Our main predictions were strongly confirmed. First, advance choices were influenced by current hunger as well as future hunger: hungry participants chose more unhealthy snacks than did satisfied ones. Second, participants were dynamically inconsistent: they chose far more unhealthy snacks for immediate choice than for advance choice. An additional hypothesis related to gender differences was also confirmed. Copyright 1998 Academic Press.

  7. The effects of massage on delayed onset muscle soreness

    PubMed Central

    Hilbert, J; Sforzo, G; Swensen, T

    2003-01-01

    Objectives: The purpose of this study was to investigate the physiological and psychological effects of massage on delayed onset muscle soreness (DOMS). Methods: Eighteen volunteers were randomly assigned to either a massage or control group. DOMS was induced with six sets of eight maximal eccentric contractions of the right hamstring, which were followed 2 h later by 20 min of massage or sham massage (control). Peak torque and mood were assessed at 2, 6, 24, and 48 h postexercise. Range of motion (ROM) and intensity and unpleasantness of soreness were assessed at 6, 24, and 48 h postexercise. Neutrophil count was assessed at 6 and 24 h postexercise. Results: A two factor ANOVA (treatment v time) with repeated measures on the second factor showed no significant treatment differences for peak torque, ROM, neutrophils, unpleasantness of soreness, and mood (p > 0.05). The intensity of soreness, however, was significantly lower in the massage group relative to the control group at 48 h postexercise (p < 0.05). Conclusions: Massage administered 2 h after exercise induced muscle injury did not improve hamstring function but did reduce the intensity of soreness 48 h after muscle insult. PMID:12547748

  8. Time-Delayed Subsidies: Interspecies Population Effects in Salmon

    PubMed Central

    Nelson, Michelle C.; Reynolds, John D.

    2014-01-01

    Cross-boundary nutrient inputs can enhance and sustain populations of organisms in nutrient-poor recipient ecosystems. For example, Pacific salmon (Oncorhynchus spp.) can deliver large amounts of marine-derived nutrients to freshwater ecosystems through their eggs, excretion, or carcasses. This has led to the question of whether nutrients from one generation of salmon can benefit juvenile salmon from subsequent generations. In a study of 12 streams on the central coast of British Columbia, we found that the abundance of juvenile coho salmon was most closely correlated with the abundance of adult pink salmon from previous years. There was a secondary role for adult chum salmon and watershed size, followed by other physical characteristics of streams. Most of the coho sampled emerged in the spring, and had little to no direct contact with spawning salmon nutrients at the time of sampling in the summer and fall. A combination of techniques suggest that subsidies from spawning salmon can have a strong, positive, time-delayed influence on the productivity of salmon-bearing streams through indirect effects from previous spawning events. This is the first study on the impacts of nutrients from naturally-occurring spawning salmon on juvenile population abundance of other salmon species. PMID:24911974

  9. Immediate and delayed effects of invented writing intervention in preschool.

    PubMed

    Hofslundsengen, Hilde; Hagtvet, Bente Eriksen; Gustafsson, Jan-Eric

    This study examined the effects of a 10 week invented writing program with five-year-old preschoolers (mean age 5.7 years) on their immediate post intervention literacy skills and also the facilitative effects of the intervention on the subsequent learning to read during the first 6 months of schooling. The study included 105 children (54 girls) from 12 preschools in Norway. The preschools were randomly assigned to the experimental group with the invented writing program, or the control group with the ordinary program offered to preschoolers. The classroom-based programs (40 sessions) were conducted by the children's regular teachers. The children's emergent literacy skills were evaluated using a pre-test, a post-test and a follow-up test 6 months later, and the data were analyzed using latent autoregressive models. The results showed that the invented writing group performed significantly better than the control group on the post-test for the measures of phoneme awareness (d = .54), spelling (d = .65) and word reading (d = .36). Additionally, indirect effects were observed on the delayed follow-up tests on phoneme awareness (d = .45), spelling (d = .48) and word reading (d = .26). In conclusion, we argue that invented writing appeared to smooth the progress of emergent literacy skills in preschool, including the subsequent reading development in school. Contextualized in a semi-consistent orthography and a preschool tradition that does not encourage the learning of written language skills, the findings add to our knowledge of how children learn to write and read.

  10. When timeliness matters: the effect of status on reactions to perceived time delay within distributed collaboration.

    PubMed

    Sheldon, Oliver J; Thomas-Hunt, Melissa C; Proell, Chad A

    2006-11-01

    This research examines the interactive effects of status and perceived time delay on acceptance of partner knowledge contributions within a distributive collaboration work environment. Results across 2 studies suggest that within distributed collaboration, time delays attributed to low-status partners had a significantly more harmful effect on influence acceptance than time delay attributed to high-status partners. This was so, despite the fact that partners' actual behavior was held constant across experimental conditions. In addition, results indicate that judgments of partner competence significantly mediated the interactive effects of perceived time delay and partner status on acceptance of partner influence. (c) 2006 APA, all rights reserved

  11. Linear time delay methods and stability analyses of the human spine. Effects of neuromuscular reflex response.

    PubMed

    Franklin, Timothy C; Granata, Kevin P; Madigan, Michael L; Hendricks, Scott L

    2008-08-01

    Linear stability methods were applied to a biomechanical model of the human musculoskeletal spine to investigate effects of reflex gain and reflex delay on stability. Equations of motion represented a dynamic 18 degrees-of-freedom rigid-body model with time-delayed reflexes. Optimal muscle activation levels were identified by minimizing metabolic power with the constraints of equilibrium and stability with zero reflex time delay. Muscle activation levels and associated muscle forces were used to find the delay margin, i.e., the maximum reflex delay for which the system was stable. Results demonstrated that stiffness due to antagonistic co-contraction necessary for stability declined with increased proportional reflex gain. Reflex delay limited the maximum acceptable proportional reflex gain, i.e., long reflex delay required smaller maximum reflex gain to avoid instability. As differential reflex gain increased, there was a small increase in acceptable reflex delay. However, differential reflex gain with values near intrinsic damping caused the delay margin to approach zero. Forward-dynamic simulations of the fully nonlinear time-delayed system verified the linear results. The linear methods accurately found the delay margin below which the nonlinear system was asymptotically stable. These methods may aid future investigations in the role of reflexes in musculoskeletal stability.

  12. Confounding Effects of Phase Delays on Causality Estimation

    PubMed Central

    Vakorin, Vasily A.; Mišić, Bratislav; Krakovska, Olga; Bezgin, Gleb; McIntosh, Anthony R.

    2013-01-01

    Linear and non-linear techniques for inferring causal relations between the brain signals representing the underlying neuronal systems have become a powerful tool to extract the connectivity patterns in the brain. Typically these tools employ the idea of Granger causality, which is ultimately based on the temporal precedence between the signals. At the same time, phase synchronization between coupled neural ensembles is considered a mechanism implemented in the brain to integrate relevant neuronal ensembles to perform a cognitive or perceptual task. Phase synchronization can be studied by analyzing the effects of phase-locking between the brain signals. However, we should expect that there is no one-to-one mapping between the observed phase lag and the time precedence as specified by physically interacting systems. Specifically, phase lag observed between two signals may interfere with inferring causal relations. This could be of critical importance for the coupled non-linear oscillating systems, with possible time delays in coupling, when classical linear cross-spectrum strategies for solving phase ambiguity are not efficient. To demonstrate this, we used a prototypical model of coupled non-linear systems, and compared three typical pipelines of inferring Granger causality, as established in the literature. Specifically, we compared the performance of the spectral and information-theoretic Granger pipelines as well as standard Granger causality in their relations to the observed phase differences for frequencies at which the signals become synchronized to each other. We found that an information-theoretic approach, which takes into account different time lags between the past of one signal and the future of another signal, was the most robust to phase effects. PMID:23349720

  13. Effect of delayed umbilical cord clamping on blood gas analysis.

    PubMed

    Valero, Javier; Desantes, Domingo; Perales-Puchalt, Alfredo; Rubio, Juan; Diago Almela, Vicente J; Perales, Alfredo

    2012-05-01

    To ascertain if there are differences in umbilical cord blood gas analysis between immediate and delayed cord clamping. In a prospective observational study on 60 vaginally delivered healthy term newborns, we sampled umbilical cord blood immediately after delivery and at the time umbilical cord pulsation spontaneously ceased. There were significant decreases in pH, oxygen saturation (sO(2)), glycemia, oxygen content (ctO(2)), bicarbonate (HCO(3)(-)) and base excess (BE). Lactate and [Formula: see text] increased. Delayed cord clamping pH correlated with immediate cord clamping pH, [Formula: see text] , ctHb, sO(2) and time (r(2)=0.77, p<0.000). Delayed cord clamping lactate was associated with immediate cord clamping lactate and time (r(2)=0.83, p<0.000). Delayed BE was associated with previous pH, lactate, glycemia, ctHb and time (r(2)=0.83, p<0.000). Delayed cord clamping alters acid-base parameters and lactate values compared to immediate cord clamping. Those variations depend mainly on time, prior pH and lactate. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  14. Teaching Effectively in Racially and Culturally Diverse Classrooms

    ERIC Educational Resources Information Center

    Ramsay, Nancy J.

    2005-01-01

    Issues of racial and cultural diversity and racism pose particular challenges for effective teaching and learning in diverse theological classrooms. In this essay the author outlines specific strategies to confront racism and engage racially and culturally diverse students. Through the use of a model for understanding multicultural dynamics of…

  15. Effect of plant diversity on the diversity of soil organic compounds

    PubMed Central

    El Moujahid, Lamiae; Michalet, Serge; Bellvert, Florian; Weigelt, Alexandra; Poly, Franck

    2017-01-01

    The effect of plant diversity on aboveground organisms and processes was largely studied but there is still a lack of knowledge regarding the link between plant diversity and soil characteristics. Here, we analyzed the effect of plant identity and diversity on the diversity of extractible soil organic compounds (ESOC) using 87 experimental grassland plots with different levels of plant diversity and based on a pool of over 50 plant species. Two pools of low molecular weight organic compounds, LMW1 and LMW2, were characterized by GC-MS and HPLC-DAD, respectively. These pools include specific organic acids, fatty acids and phenolics, with more organic acids in LMW1 and more phenolics in LMW2. Plant effect on the diversity of LMW1 and LMW2 compounds was strong and weak, respectively. LMW1 richness observed for bare soil was lower than that observed for all planted soils; and the richness of these soil compounds increased twofold when dominant plant species richness increased from 1 to 6. Comparing the richness of LMW1 compounds observed for a range of plant mixtures and for plant monocultures of species present in these mixtures, we showed that plant species richness increases the richness of these ESOC mainly through complementarity effects among plant species associated with contrasted spectra of soil compounds. This could explain previously reported effects of plant diversity on the diversity of soil heterotrophic microorganisms. PMID:28166250

  16. Effect of plant diversity on the diversity of soil organic compounds.

    PubMed

    El Moujahid, Lamiae; Le Roux, Xavier; Michalet, Serge; Bellvert, Florian; Weigelt, Alexandra; Poly, Franck

    2017-01-01

    The effect of plant diversity on aboveground organisms and processes was largely studied but there is still a lack of knowledge regarding the link between plant diversity and soil characteristics. Here, we analyzed the effect of plant identity and diversity on the diversity of extractible soil organic compounds (ESOC) using 87 experimental grassland plots with different levels of plant diversity and based on a pool of over 50 plant species. Two pools of low molecular weight organic compounds, LMW1 and LMW2, were characterized by GC-MS and HPLC-DAD, respectively. These pools include specific organic acids, fatty acids and phenolics, with more organic acids in LMW1 and more phenolics in LMW2. Plant effect on the diversity of LMW1 and LMW2 compounds was strong and weak, respectively. LMW1 richness observed for bare soil was lower than that observed for all planted soils; and the richness of these soil compounds increased twofold when dominant plant species richness increased from 1 to 6. Comparing the richness of LMW1 compounds observed for a range of plant mixtures and for plant monocultures of species present in these mixtures, we showed that plant species richness increases the richness of these ESOC mainly through complementarity effects among plant species associated with contrasted spectra of soil compounds. This could explain previously reported effects of plant diversity on the diversity of soil heterotrophic microorganisms.

  17. The Effects of Download Delay on Performance and End-User Satisfaction in an Internet Tutorial.

    ERIC Educational Resources Information Center

    Davis, Erica S.; Hantula, Donald A.

    2001-01-01

    Describes a study of university students that investigated the effects of a variable unique to Internet-based learning, namely download delay of instructional materials. Discusses a simulated online teaching tool that measured the effects of download delay of images on test performance, time spent on the material, end-user satisfaction, and…

  18. Impacts of Wake Effect and Time Delay on the Dynamic Analysis of Wind Farms Models

    ERIC Educational Resources Information Center

    El-Fouly, Tarek H. M.; El-Saadany, Ehab F.; Salama, Magdy M. A.

    2008-01-01

    This article investigates the impacts of proper modeling of the wake effects and wind speed delays, between different wind turbines' rows, on the dynamic performance accuracy of the wind farms models. Three different modeling scenarios were compared to highlight the impacts of wake effects and wind speed time-delay models. In the first scenario,…

  19. Impacts of Wake Effect and Time Delay on the Dynamic Analysis of Wind Farms Models

    ERIC Educational Resources Information Center

    El-Fouly, Tarek H. M.; El-Saadany, Ehab F.; Salama, Magdy M. A.

    2008-01-01

    This article investigates the impacts of proper modeling of the wake effects and wind speed delays, between different wind turbines' rows, on the dynamic performance accuracy of the wind farms models. Three different modeling scenarios were compared to highlight the impacts of wake effects and wind speed time-delay models. In the first scenario,…

  20. Effect of delayed auditory feedback on normal speakers at two speech rates

    NASA Astrophysics Data System (ADS)

    Stuart, Andrew; Kalinowski, Joseph; Rastatter, Michael P.; Lynch, Kerry

    2002-05-01

    This study investigated the effect of short and long auditory feedback delays at two speech rates with normal speakers. Seventeen participants spoke under delayed auditory feedback (DAF) at 0, 25, 50, and 200 ms at normal and fast rates of speech. Significantly two to three times more dysfluencies were displayed at 200 ms (p<0.05) relative to no delay or the shorter delays. There were significantly more dysfluencies observed at the fast rate of speech (p=0.028). These findings implicate the peripheral feedback system(s) of fluent speakers for the disruptive effects of DAF on normal speech production at long auditory feedback delays. Considering the contrast in fluency/dysfluency exhibited between normal speakers and those who stutter at short and long delays, it appears that speech disruption of normal speakers under DAF is a poor analog of stuttering.

  1. Effects of Fatigue on Voluntary Electromechanical and Relaxation Electromechanical Delay.

    PubMed

    Smith, Cory M; Housh, Terry J; Hill, Ethan C; Keller, Joshua L; Johnson, Glen O; Schmidt, Richard J

    2017-09-01

    The purposes of the present study were to examine: 1) the effects of fatigue on electromechanical delay from the onsets of the electromyographic signal to force production (EMDE-F), the onsets of the electromyographic to mechanomyographic signals (EMDE-M), the onsets of the mechanomyographic signal to force production (EMDM-F), as well as the cessations of the electromyographic to force production (R-EMDE-F), cessation of the electromyographic to mechanomyographic signals (R-EMDE-M), and cessations of the mechanomyographic signal to force production (R-EMDM-F); and 2) the relative contributions from EMDE-M and EMDM-F to EMDE-F as well as R-EMDE-M and R-EMDM-F to R-EMDE-F from the vastus lateralis in non-fatigued and fatigued states. The values EMDE-F, EMDE-M, EMDM-F, R-EMDE-F, R-EMDE-M and R-EMDM-F were calculated during maximal voluntary isometric contractions, before and after 70% 1-repetition maximum leg extensions to failure. There were significant pretest to posttest increases in EMDE-F (73%;p<0.01), EMDE-M (99%;p<0.01), EMDM-F (60%;p<0.01), R-EMDE-F (101%;p<0.01) and R-EMDM-F (368%;p<0.01), but no significant change in R-EMDE-M (25%;p=0.46). Fatigue-induced increase in EMDE-F indicated excitation-contraction coupling failure (EMDE-M) and increases in the compliance of the series elastic component (EMDM-F). Increases in R-EMDE-F were due to increases in relaxation time for the series elastic component (R-EMDM-F), but not changes in the reversal of excitation-contraction coupling (R-EMDE-M). © Georg Thieme Verlag KG Stuttgart · New York.

  2. Cultural Diversity in Military Teams: Which Factors Influence Effectiveness?

    DTIC Science & Technology

    2008-12-01

    could lead to problems in terms of team satisfaction and team performance. Some studies have addressed the impact of cultural diversity on team... leading to better performance and more satisfaction. Watson. Johnson, and Zgourides (2002) compared ethnically diverse and non-diverse teams of...operationalized diversity in terms of ethnic minority as well as gender and persons with disabilities and found a positive effect of gender and minority

  3. Residual Stress Effect on the Delayed Fracture of Twinning-Induced Plasticity Steels

    NASA Astrophysics Data System (ADS)

    Kim, Jung Gi; Yoon, Jae Ik; Baek, Seung Mi; Seo, Min Hong; Cho, Won Tae; Chin, Kwang-Geun; Lee, Sunghak; Kim, Hyoung Seop

    2017-03-01

    Residual stress effect of the deep drawn TWIP steel on delayed fracture was investigated. Microstructural features of the TWIP steels did not change after stress relief annealing, while the elastic lattice strain dropped to 0.0007. Delayed fracture of the drawn TWIP steel occurred after 203 hours of HCl immersion testing, but did not occur in the annealed one. It is clear that residual stress after the drawing is the primary reason for the delayed fracture of TWIP steels.

  4. Residual Stress Effect on the Delayed Fracture of Twinning-Induced Plasticity Steels

    NASA Astrophysics Data System (ADS)

    Kim, Jung Gi; Yoon, Jae Ik; Baek, Seung Mi; Seo, Min Hong; Cho, Won Tae; Chin, Kwang-Geun; Lee, Sunghak; Kim, Hyoung Seop

    2017-06-01

    Residual stress effect of the deep drawn TWIP steel on delayed fracture was investigated. Microstructural features of the TWIP steels did not change after stress relief annealing, while the elastic lattice strain dropped to 0.0007. Delayed fracture of the drawn TWIP steel occurred after 203 hours of HCl immersion testing, but did not occur in the annealed one. It is clear that residual stress after the drawing is the primary reason for the delayed fracture of TWIP steels.

  5. Decomposer diversity and identity influence plant diversity effects on ecosystem functioning.

    PubMed

    Eisenhauer, Nico; Reich, Peter B; Isbell, Forest

    2012-10-01

    Plant productivity and other ecosystem functions often increase with plant diversity at a local scale. Alongside various plant-centered explanations for this pattern, there is accumulating evidence that multi-trophic interactions shape this relationship. Here, we investigated for the first time if plant diversity effects on ecosystem functioning are mediated or driven by decomposer animal diversity and identity using a double-diversity microcosm experiment. We show that many ecosystem processes and ecosystem multifunctionality (herbaceous shoot biomass production, litter removal, and N uptake) were affected by both plant and decomposer diversity, with ecosystem process rates often being maximal at intermediate to high plant and decomposer diversity and minimal at both low plant and decomposer diversity. Decomposers relaxed interspecific plant competition by enlarging chemical (increased N uptake and surface-litter decomposition) and spatial (increasing deep-root biomass) habitat space and by promoting plant complementarity. Anecic earthworms and isopods functioned as key decomposers; although decomposer diversity effects did not solely rely on these two decomposer species, positive plant net biodiversity and complementarity effects only occurred in the absence of isopods and the presence of anecic earthworms. Using a structural equation model, we explained 76% of the variance in plant complementarity, identified direct and indirect effect paths, and showed that the presence of key decomposers accounted for approximately three-quarters of the explained variance. We conclude that decomposer animals have been underappreciated as contributing agents of plant diversity-ecosystem functioning relationships. Elevated decomposer performance at high plant diversity found in previous experiments likely positively feeds back to plant performance, thus contributing to the positive relationship between plant diversity and ecosystem functioning.

  6. Effects of Methylprednisolone on Neuroprotective Effects of Delay Hypothermia on Spinal Cord Injury in Rat

    PubMed Central

    Akhtarshomar, Sadegh; Saied, Alireza; Gholamhoseinian, Ahmad

    2015-01-01

    Study Design A retrospective study. Purpose The aim of this study was to evaluate the effects of delayed hypothermia on spinal cord injuries in rats. In addition, the effect of methylprednisolone on therapeutic window of hypothermia was evaluated. Overview of Literature Several studies have demonstrated that early hypothermia is the most effective neuroprotective modality. However, delayed hypothermia seems to be more practical for patients with traumatic spinal cord injuries. A combination of hypothermia and other neuroprotective methods, such as using methylprednisolone, may help extend the therapeutic window of hypothermia. Methods One hundred and twenty male rats were categorized into six groups. The rats in five groups were subjected to spinal cord injury using the weight drop method, followed by treatment, consisting of early hypothermia, late hypothermia, late hypothermia plus methylprednisolone, or methylprednisolone only. Biochemical tests including catalase, malondialdehyde, and superoxide level were evaluated in the injured spinal cord. Behavioral functions of the hind limb were evaluated by Basso-Battle-Bresnaham locomotor rating scale and tail-flick tests. Results Functional and biochemical evaluation showed both early and late hypothermia had significant neuroprotective effects. The treated groups did not differ significantly from one another in the behavioral tests. Hypothermia had better biochemical results compared to methylprednisolone. Also, methylprednisolone was shown to extend the therapeutic window of delayed hypothermia. Conclusions Hypothermia showed a significant neuroprotective effect, which can be improved with further studies optimizing the duration of hypothermia and the rewarming period. Moreover, the therapeutic effect of the delayed hypothermia can be extended by methylprednisolone. PMID:25705328

  7. Effect of multiple time delays on intensity fluctuation dynamics in fiber ring lasers.

    PubMed

    Franz, Anthony L; Roy, Rajarshi; Shaw, Leah B; Schwartz, Ira B

    2008-07-01

    The effect of time delay on nonlinear oscillators is an important problem in the study of dynamical systems. The dynamics of an erbium-doped fiber ring laser with an extra loop providing time-delayed feedback is studied experimentally by measuring the intensity of the laser. The delay time for the feedback is varied from approximately 0.3 to approximately 900 times the cavity round-trip time, over four orders of magnitude, by changing the length of fiber in the delay line. Depending on the delay, we observe either regular oscillations or complex dynamics. The size of the fluctuations increases for delays long compared with the round-trip time of the laser cavity. The complexity of the fluctuations is quantified by creating spatiotemporal representations of the time series and performing a Karhunen-Loève decomposition. The complexity increases with increasing delay time. The experiment is extended by mutually coupling two fiber ring lasers together. The delay time for the mutual coupling is varied from approximately 0.2 to approximately 600 times the cavity round-trip time, over four orders of magnitude again. In this case the fluctuations are generally larger than the single laser case. The complexity of the dynamics for the mutually coupled system is less at short delays and larger at long delays when compared to the uncoupled case. The width of the optical spectra of the coupled lasers also narrows.

  8. Understanding the Delayed-Keyword Effect on Metacomprehension Accuracy

    ERIC Educational Resources Information Center

    Thiede, Keith W.; Dunlosky, John; Griffin, Thomas D.; Wiley, Jennifer

    2005-01-01

    The typical finding from research on metacomprehension is that accuracy is quite low. However, recent studies have shown robust accuracy improvements when judgments follow certain generation tasks (summarizing or keyword listing) but only when these tasks are performed at a delay rather than immediately after reading (K. W. Thiede & M. C. M.…

  9. The Effect of Concurrent Semantic Categorization on Delayed Serial Recall

    ERIC Educational Resources Information Center

    Acheson, Daniel J.; MacDonald, Maryellen C.; Postle, Bradley R.

    2011-01-01

    The influence of semantic processing on the serial ordering of items in short-term memory was explored using a novel dual-task paradigm. Participants engaged in 2 picture-judgment tasks while simultaneously performing delayed serial recall. List material varied in the presence of phonological overlap (Experiments 1 and 2) and in semantic content…

  10. The Effect of Concurrent Semantic Categorization on Delayed Serial Recall

    ERIC Educational Resources Information Center

    Acheson, Daniel J.; MacDonald, Maryellen C.; Postle, Bradley R.

    2011-01-01

    The influence of semantic processing on the serial ordering of items in short-term memory was explored using a novel dual-task paradigm. Participants engaged in 2 picture-judgment tasks while simultaneously performing delayed serial recall. List material varied in the presence of phonological overlap (Experiments 1 and 2) and in semantic content…

  11. [Effects of global change on soil fauna diversity: A review].

    PubMed

    Wu, Ting-Juan

    2013-02-01

    Terrestrial ecosystem consists of aboveground and belowground components, whose interaction affects the ecosystem processes and functions. Soil fauna plays an important role in biogeochemical cycles. With the recognizing of the significance of soil fauna in ecosystem processes, increasing evidences demonstrated that global change has profound effects on soil faunima diversity. The alternation of land use type, the increasing temperature, and the changes in precipitation pattern can directly affect soil fauna diversity, while the increase of atmospheric CO2 concentration and nitrogen deposition can indirectly affect the soil fauna diversity by altering plant community composition, diversity, and nutrient contents. The interactions of different environmental factors can co-affect the soil fauna diversity. To understand the effects of different driving factors on soil fauna diversity under the background of climate change would facilitate us better predicting how the soil fauna diversity and related ecological processes changed in the future.

  12. Effects of computing time delay on real-time control systems

    NASA Technical Reports Server (NTRS)

    Shin, Kang G.; Cui, Xianzhong

    1988-01-01

    The reliability of a real-time digital control system depends not only on the reliability of the hardware and software used, but also on the speed in executing control algorithms. The latter is due to the negative effects of computing time delay on control system performance. For a given sampling interval, the effects of computing time delay are classified into the delay problem and the loss problem. Analysis of these two problems is presented as a means of evaluating real-time control systems. As an example, both the self-tuning predicted (STP) control and Proportional-Integral-Derivative (PID) control are applied to the problem of tracking robot trajectories, and their respective effects of computing time delay on control performance are comparatively evaluated. For this example, the STP (PID) controller is shown to outperform the PID (STP) controller in coping with the delay (loss) problem.

  13. Effect of time delay on pattern dynamics in a spatial epidemic model

    NASA Astrophysics Data System (ADS)

    Wang, Yi; Cao, Jinde; Sun, Gui-Quan; Li, Jing

    2014-10-01

    Time delay, accounting for constant incubation period or sojourn times in an infective state, widely exists in most biological systems like epidemiological models. However, the effect of time delay on spatial epidemic models is not well understood. In this paper, spatial pattern of an epidemic model with both nonlinear incidence rate and time delay is investigated. In particular, we mainly focus on the effect of time delay on the formation of spatial pattern. Through mathematical analysis, we gain the conditions for Hopf bifurcation and Turing bifurcation, and find exact Turing space in parameter space. Furthermore, numerical results show that time delay has a significant effect on pattern formation. The simulation results may enrich the finding of patterns and may well capture some key features in the epidemic models.

  14. Effects of computing time delay on real-time control systems

    NASA Technical Reports Server (NTRS)

    Shin, Kang G.; Cui, Xianzhong

    1988-01-01

    The reliability of a real-time digital control system depends not only on the reliability of the hardware and software used, but also on the speed in executing control algorithms. The latter is due to the negative effects of computing time delay on control system performance. For a given sampling interval, the effects of computing time delay are classified into the delay problem and the loss problem. Analysis of these two problems is presented as a means of evaluating real-time control systems. As an example, both the self-tuning predicted (STP) control and Proportional-Integral-Derivative (PID) control are applied to the problem of tracking robot trajectories, and their respective effects of computing time delay on control performance are comparatively evaluated. For this example, the STP (PID) controller is shown to outperform the PID (STP) controller in coping with the delay (loss) problem.

  15. The Effects of Inflation and Interest Rates on Delay Discounting in Human Behavior

    ERIC Educational Resources Information Center

    Kawashima, Kentaro

    2006-01-01

    Interest and inflation rates may be major determinants of delay discounting, but these variables have not been controlled in past experiments because they depend on macroeconomic conditions. This study uses a computer game-like task to investigate the effects of inflation rates on people's subjective valuation of delayed rewards. During the task,…

  16. The Effects of Inflation and Interest Rates on Delay Discounting in Human Behavior

    ERIC Educational Resources Information Center

    Kawashima, Kentaro

    2006-01-01

    Interest and inflation rates may be major determinants of delay discounting, but these variables have not been controlled in past experiments because they depend on macroeconomic conditions. This study uses a computer game-like task to investigate the effects of inflation rates on people's subjective valuation of delayed rewards. During the task,…

  17. Interactive Effects of Graphic Organizers and Delayed Review on Concept Application.

    ERIC Educational Resources Information Center

    Robinson, Daniel H.; Katayama, Andrew D.; Dubois, Nelson F.; Devaney, Thomas

    1998-01-01

    Investigated the effects of immediate and delayed review occasion and study materials (text, text plus outlines, and text plus graphic organizers) in two experiments involving 198 undergraduates. Delayed review facilitated performance for students who viewed text plus graphic organizers but not for those who viewed only text or text plus outlines.…

  18. The Effect of D-Cycloserine on Immediate vs. Delayed Extinction of Learned Fear

    ERIC Educational Resources Information Center

    Langton, Julia M.; Richardson, Rick

    2010-01-01

    We compared the effect of D-cycloserine (DCS) on immediate (10 min after conditioning) and delayed (24 h after conditioning) extinction of learned fear in rats. DCS facilitated both immediate and delayed extinction when the drug was administered after extinction training. However, DCS did not facilitate immediate extinction when administered prior…

  19. The Effect of D-Cycloserine on Immediate vs. Delayed Extinction of Learned Fear

    ERIC Educational Resources Information Center

    Langton, Julia M.; Richardson, Rick

    2010-01-01

    We compared the effect of D-cycloserine (DCS) on immediate (10 min after conditioning) and delayed (24 h after conditioning) extinction of learned fear in rats. DCS facilitated both immediate and delayed extinction when the drug was administered after extinction training. However, DCS did not facilitate immediate extinction when administered prior…

  20. Effects of polyandry on male phenotypic diversity.

    PubMed

    Barbosa, M; Dornelas, M; Magurran, A E

    2010-11-01

    Polyandry has the potential to affect the distribution of phenotypes and to shape the direction of sexual selection. Here, we explore this potential using Trinidadian guppies as a model system and ask whether polyandry leads to directional and/or diversifying selection of male phenotypic traits. In this study, we compare the phenotypic diversity of offspring from multiply and singly sired broods. To quantify phenotypic diversity, we first combine phenotypic traits using multivariate methods, and then take the dispersion of individuals in multivariate space as our measure of diversity. We show that, when each trait is examined separately, polyandry generates offspring with a higher proportion of bright coloration, indicating directional selection. However, our multivariate approach reveals that this directionality is accompanied by an increase in phenotypic diversity. These results suggest that polyandry (i) selects for the production of sons with the preferred brighter colour phenotypes whereas (ii) enhancing the diversity of male sexual traits. Promoting phenotypic diversity may be advantageous in coping with environmental and reproductive variability by increasing long-term fitness. © 2010 The Authors. Journal Compilation © 2010 European Society For Evolutionary Biology.

  1. Connected cruise control: modelling, delay effects, and nonlinear behaviour

    NASA Astrophysics Data System (ADS)

    Orosz, Gábor

    2016-08-01

    Connected vehicle systems (CVS) are considered in this paper where vehicles exchange information using wireless vehicle-to-vehicle (V2V) communication. The concept of connected cruise control (CCC) is established that allows control design at the level of individual vehicles while exploiting V2V connectivity. Due to its high level of modularity the proposed design can be applied to large heterogeneous traffic systems. The dynamics of a simple CVS is analysed in detail while taking into account nonlinearities in the vehicle dynamics as well as in the controller. Time delays that arise due to intermittencies and packet drops in the communication channels are also incorporated. The results are summarised using stability charts which allow one to select control gains to maintain stability and ensure disturbance attenuation when the delay is below a critical value.

  2. The effects of remote SST forcings on ENSO dynamics, variability and diversity

    NASA Astrophysics Data System (ADS)

    Dommenget, Dietmar; Yu, Yanshan

    2016-12-01

    Air-sea interactions with remote regions in the tropical Indian and Atlantic, and extra-tropical oceans can influence ENSO features in the tropical Pacific. In this study these effects are explored by using an AGCM coupled with a Slab Ocean and a simple recharge oscillator ENSO model through switched on/off air-sea interaction in respective ocean area. It is shown that the decoupling in different remote regions has different impacts on ENSO dynamics, variability and diversity. The most interesting result is that the air-sea interactions with remote tropical oceans provide a delayed negative feedback to ENSO similar to that of the tropical Pacific Ocean internal wave dynamics. This is caused by the ENSO teleconnections: they lead to a delayed remote warming and cooling, which in turn feedbacks to ENSO effectively giving a delayed negative feedback. The model simulations suggest that this remote delayed feedback may contribute about 40% to the total delayed negative feedback of ENSO. Thus a central element of ENSO dynamics is partly due to interactions with other tropical ocean basins by atmospheric teleconnections. Furthermore, all remote regions effectively provide stochastic forcings for the ENSO variability and therefore increase the ENSO variability. The influence from the remote regions also causes different patterns of sea surface temperature (SST) variability in the tropical Pacific, contributing to the diversity of the ENSO mode. In particular the extra-tropical Pacific regions force SST variability that is different from the equatorial ENSO mode of variability. The influence that the remote regions have on the ENSO dynamics and variability is significantly altered by the interaction between the equatorial recharge oscillator dynamics and the simple thermodynamic slab ocean processes.

  3. Briefly delayed reinforcement effects on variable-ratio and yoked-interval schedule performance.

    PubMed

    Holtyn, August F; Lattal, Kennon A

    2013-09-01

    Most investigations of briefly delayed reinforcement have involved schedules that arrange a time-plus-response requirement. The present experiment examined whether briefly delaying reinforcement on schedules that have a ratio requirement differs from results with schedules that have a time-plus-response requirement. Four pigeons responded on a two-component multiple schedule. One component arranged a variable-ratio (VR) 50 and the other a variable-interval (VI) schedule in which the distribution of reinforcers was yoked to the preceding VR schedule. Across a series of conditions, delays were imposed in both schedules. These delays were brief (0.25- or 0.5-s) unsignaled delays and, as control conditions, a 5-s unsignaled delay and a 0.5-s delay signaled by a blackout of the chamber. In the yoked-VI component, the brief unsignaled delay increased response rates in six of nine opportunities and increased the proportion of short interresponse times (IRTs) (<0.4 s) in eight of nine opportunities. In the VR component, the brief unsignaled delay increased response rates and the proportion of short IRTs in only two of nine opportunities. For two of the three pigeons that were exposed to the 5-s unsignaled delay, response rates and the proportion of short IRTs decreased in both of the components. The 0.5-s signaled delay did not systematically change response rates nor did it change the distribution of short IRTs relative to the immediate reinforcement condition. The results replicate effects reported with time-based schedules and extend these observations by showing that changes commonly observed in VI performance with briefly delayed reinforcement are not characteristic of VR responding.

  4. The Effects of Pitch Shifts on Delay-Induced Changes in Vocal Sequencing in a Songbird.

    PubMed

    Wyatt, MacKenzie; Berthiaume, Emily A; Kelly, Conor W; Sober, Samuel J

    2017-01-01

    Like human speech, vocal behavior in songbirds depends critically on auditory feedback. In both humans and songbirds, vocal skills are acquired by a process of imitation whereby current vocal production is compared to an acoustic target. Similarly, performance in adulthood relies strongly on auditory feedback, and online manipulations of auditory signals can dramatically alter acoustic production even after vocalizations have been well learned. Artificially delaying auditory feedback can disrupt both speech and birdsong, and internal delays in auditory feedback have been hypothesized as a cause of vocal dysfluency in persons who stutter. Furthermore, in both song and speech, online shifts of the pitch (fundamental frequency) of auditory feedback lead to compensatory changes in vocal pitch for small perturbations, but larger pitch shifts produce smaller changes in vocal output. Intriguingly, large pitch shifts can partially restore normal speech in some dysfluent speakers, suggesting that the effects of auditory feedback delays might be ameliorated by online pitch manipulations. Although birdsong provides a promising model system for understanding speech production, the interactions between sensory feedback delays and pitch shifts have not yet been assessed in songbirds. To investigate this, we asked whether the addition of a pitch shift modulates delay-induced changes in Bengalese finch song, hypothesizing that pitch shifts would reduce the effects of feedback delays. Compared with the effects of delays alone, combined delays and pitch shifts resulted in a significant reduction in behavioral changes in one type of sequencing (branch points) but not another (distribution of repeated syllables).

  5. The Effects of Pitch Shifts on Delay-Induced Changes in Vocal Sequencing in a Songbird

    PubMed Central

    Kelly, Conor W.

    2017-01-01

    Abstract Like human speech, vocal behavior in songbirds depends critically on auditory feedback. In both humans and songbirds, vocal skills are acquired by a process of imitation whereby current vocal production is compared to an acoustic target. Similarly, performance in adulthood relies strongly on auditory feedback, and online manipulations of auditory signals can dramatically alter acoustic production even after vocalizations have been well learned. Artificially delaying auditory feedback can disrupt both speech and birdsong, and internal delays in auditory feedback have been hypothesized as a cause of vocal dysfluency in persons who stutter. Furthermore, in both song and speech, online shifts of the pitch (fundamental frequency) of auditory feedback lead to compensatory changes in vocal pitch for small perturbations, but larger pitch shifts produce smaller changes in vocal output. Intriguingly, large pitch shifts can partially restore normal speech in some dysfluent speakers, suggesting that the effects of auditory feedback delays might be ameliorated by online pitch manipulations. Although birdsong provides a promising model system for understanding speech production, the interactions between sensory feedback delays and pitch shifts have not yet been assessed in songbirds. To investigate this, we asked whether the addition of a pitch shift modulates delay-induced changes in Bengalese finch song, hypothesizing that pitch shifts would reduce the effects of feedback delays. Compared with the effects of delays alone, combined delays and pitch shifts resulted in a significant reduction in behavioral changes in one type of sequencing (branch points) but not another (distribution of repeated syllables). PMID:28144622

  6. Time delay and the effect of the finite speed of light in atom gravimeters

    NASA Astrophysics Data System (ADS)

    Tan, Yu-Jie; Shao, Cheng-Gang; Hu, Zhong-Kun

    2017-08-01

    The propagation time delay due to the finite speed of light (FSL) in atom gravimeters introduces a bias in the gravity measurement, as well as that in classical free-falling corner-cube gravimeters, which is usually termed the FSL effect. For a typical atom gravimeter, the FSL time delay is about several nanoseconds, resulting in the FSL effect, a non-negligible bias in the gravity-acceleration measurement. However, a time delay of about several microseconds, achieved by controlling the Raman-pulse timing directly, contributes a negligible effect. This interesting phenomenon motivates us to make clear two questions: first, what are the origins of the FSL effect in atom gravimeters, and second, what is the difference between the two time delays? Our analysis shows that the FSL effect in atom gravimeters is not just a matter of FSL time delay to a great extent but also the change in the effective wave vector; moreover, the FSL time delay can be quantitatively regarded as the same as the pulse time delay since both actually affect the gravity measurement by changing the two interferometer pulse separations.

  7. Delays in Human-Computer Interaction and Their Effects on Brain Activity.

    PubMed

    Kohrs, Christin; Angenstein, Nicole; Brechmann, André

    2016-01-01

    The temporal contingency of feedback is an essential requirement of successful human-computer interactions. The timing of feedback not only affects the behavior of a user but is also accompanied by changes in psychophysiology and neural activity. In three fMRI experiments we systematically studied the impact of delayed feedback on brain activity while subjects performed an auditory categorization task. In the first fMRI experiment, we analyzed the effects of rare and thus unexpected delays of different delay duration on brain activity. In the second experiment, we investigated if users can adapt to frequent delays. Therefore, delays were presented as often as immediate feedback. In a third experiment, the influence of interaction outage was analyzed by measuring the effect of infrequent omissions of feedback on brain activity. The results show that unexpected delays in feedback presentation compared to immediate feedback stronger activate inter alia bilateral the anterior insular cortex, the posterior medial frontal cortex, the left inferior parietal lobule and the right inferior frontal junction. The strength of this activation increases with the duration of the delay. Thus, delays interrupt the course of an interaction and trigger an orienting response that in turn activates brain regions of action control. If delays occur frequently, users can adapt, delays become expectable, and the brain activity in the observed network diminishes over the course of the interaction. However, introducing rare omissions of expected feedback reduces the system's trustworthiness which leads to an increase in brain activity not only in response to such omissions but also following frequently occurring and thus expected delays.

  8. Effects of delay to reinforcement on the choice between cocaine and food in rhesus monkeys.

    PubMed

    Woolverton, William L; Anderson, Karen G

    2006-05-01

    Although a delay between behavior and reinforcer has been shown to weaken behavior, little is known about the effects of delay on drug choice. The present study examined effects of delay between lever press and reinforcer presentation on the choice between a drug and non-drug reinforcer and between different drug doses. Monkeys (n=4) were allowed to choose 32 times/day between cocaine and four food pellets. The delay between lever press and a preferred dose of cocaine (0.05 mg/kg/injection) was increased systematically from 0 to 240 s, while the delay to food remained at 0 s. A second group of monkeys (n=4) was allowed to choose between 0.05 mg/kg/injection and a lower dose of cocaine (0.025 mg/kg/injection). Next, a delay that resulted in less than 20% choice of 0.05 mg/kg/injection cocaine was selected and delay to the alternative was varied. Results were similar across groups. The choice of 0.05 mg/kg/injection approximated 100% at 0 delay and decreased to near 0 as delay increased. As the delay to alternative was subsequently increased from 0 to 240 s, choice of 0.05 mg/kg/injection increased, though full cocaine choice was not generally restored. The delay estimated to maintain 50% choice (indifference point) was lower for the cocaine-food choice (mean=64 s) than for the cocaine-cocaine choice (mean=207 s). This experiment demonstrates that the choice between cocaine and a non-drug or drug alternative can be modified by increasing the interval between behavior and drug injection. Overall, the results are consistent with a temporal discounting model of drug choice.

  9. Delays in Human-Computer Interaction and Their Effects on Brain Activity

    PubMed Central

    Kohrs, Christin; Angenstein, Nicole; Brechmann, André

    2016-01-01

    The temporal contingency of feedback is an essential requirement of successful human-computer interactions. The timing of feedback not only affects the behavior of a user but is also accompanied by changes in psychophysiology and neural activity. In three fMRI experiments we systematically studied the impact of delayed feedback on brain activity while subjects performed an auditory categorization task. In the first fMRI experiment, we analyzed the effects of rare and thus unexpected delays of different delay duration on brain activity. In the second experiment, we investigated if users can adapt to frequent delays. Therefore, delays were presented as often as immediate feedback. In a third experiment, the influence of interaction outage was analyzed by measuring the effect of infrequent omissions of feedback on brain activity. The results show that unexpected delays in feedback presentation compared to immediate feedback stronger activate inter alia bilateral the anterior insular cortex, the posterior medial frontal cortex, the left inferior parietal lobule and the right inferior frontal junction. The strength of this activation increases with the duration of the delay. Thus, delays interrupt the course of an interaction and trigger an orienting response that in turn activates brain regions of action control. If delays occur frequently, users can adapt, delays become expectable, and the brain activity in the observed network diminishes over the course of the interaction. However, introducing rare omissions of expected feedback reduces the system’s trustworthiness which leads to an increase in brain activity not only in response to such omissions but also following frequently occurring and thus expected delays. PMID:26745874

  10. Effective numbers in the partitioning of biological diversity.

    PubMed

    Gregorius, Hans-Rolf

    2016-11-21

    Admissible measures of diversity allow specification of the number of types (species, alleles, etc.) that are "effectively" involved in producing the diversity (the "diversity effective number", also referred to as "true diversity") of a community or population. In metacommunities, effective numbers additionally serve in partitioning the total diversity (symbolized by γ) into one component summarizing the diversity within communities (symbolized by α) and an independent component summarizing the differences between communities (symbolized by β). There is growing consensus that the β-component should be treated in terms of an effective number of "distinct" communities in the metacommunity. Yet, the notion of distinctness is shown in the present paper to remain conceptually ambiguous at least with respect to the diversity within the "distinct" communities. To overcome this ambiguity and to provide the means for designing further desirable effective numbers, a new approach is taken that involves a generalized concept of effective number. The approach relies on first specifying the distributional characteristics of partitioning diversity among communities (among which are differentiation, where the same types tend to occur in the same communities, and apportionment, where different types tend to occur in different communities), then developing the indices which measure these characteristics, and finally inferring the effective numbers from these indices. (1) The β-component reflects apportionment characteristics of metacommunity structure and is quantified by the "apportionment effective number" of communities (number of effectively monomorphic communities). Since differentiation between communities arises only as a side effect of apportionment, the common interpretation of the β-component in terms of differentiation is unwarranted. (2) Multiplicative as well as additive methods of partitioning the total type diversity (γ) involve apportionment effective numbers

  11. Effect of delayed reporting of band recoveries on survival estimates

    USGS Publications Warehouse

    Anderson, David R.; Burnham, Kenneth P.

    1980-01-01

    Brownie et al. (U.S. Fish and Wildl. Serv., Resource Publ. 131, 1978) presented 14 models based on an array of explicit assumptions for the study of survival in avian populations. These methods are replacing the life table methods previously used to estimate survival rates (e.g., Burnham and Anderson, J. Wildl. Manage., 43: 356-366, 1979). The new methods allow survival or recovery rates, or both, to be constant, time-specific, or time- and age-specific. In studies to estimate survival rates for birds the data are often from recoveries of birds shot or found dead during the hunting season and reported to the Bird Banding Laboratory by sportsmen, conservation agency employees, or the general public. This note examines the bias in estimating annual survival due to a proportion of the recoveries being incorrectly reported a year late. Specifically, a few recoveries each year of, for example, adult male American Widgeon (Anas americana) banded in California are reported as being recovered in year i + 1 when in fact they were actually recovered the previous year i. Delayed reporting might typically be caused by people finding a band in their health clothing in the fall of the year and, being embarrassed about their failure to report the band when it was taken, report it a year late not mentioning the actual year of recovery. Heuristically, delayed reporting should bias estimated annual survival rates upwards because it appears from the data that the birds corresponding to the "delayed" recoveries actually lived an additional year.

  12. Individualization and Diversity: Antecedents to Institutional Effectiveness.

    ERIC Educational Resources Information Center

    Burley, Hansel

    1996-01-01

    Argues that if educational institutions wish to achieve the goal of cultural diversity, they must go beyond curricula that transmit culture (that is, the core curriculum) or transform culture (that is, multiculturalism) and embrace a curriculum that enhances individual differences. Maintains that institutions should affirm students' individual…

  13. Study on Effects of the Stochastic Delay Probability for 1d CA Model of Traffic Flow

    NASA Astrophysics Data System (ADS)

    Xue, Yu; Chen, Yan-Hong; Kong, Ling-Jiang

    Considering the effects of different factors on the stochastic delay probability, the delay probability has been classified into three cases. The first case corresponding to the brake state has a large delay probability if the anticipant velocity is larger than the gap between the successive cars. The second one corresponding to the following-the-leader rule has intermediate delay probability if the anticipant velocity is equal to the gap. Finally, the third case is the acceleration, which has minimum delay probability. The fundamental diagram obtained by numerical simulation shows the different properties compared to that by the NaSch model, in which there exist two different regions, corresponding to the coexistence state, and jamming state respectively.

  14. The delaying effect of stigma on mental health help-seeking in Sri Lanka.

    PubMed

    Fernando, Sunera M; Deane, Frank P; McLeod, Hamish J

    2017-03-01

    Mental health stigma has been associated with delays in seeking treatment. To describe perceived stigma experienced by patients and carers in Sri Lanka and to determine the effects of stigma on help-seeking delay. Survey of outpatients and family carers (n = 118 dyads) attending two psychiatric hospitals in Sri Lanka, using the Disclosure and Discrimination subscales of the Stigma Scale. Stigma was positively related to help-seeking delay for carers but not patients. Public stigma experienced by carers accounted for 23% of the variance in help-seeking delay. Reducing stigma may reduce help-seeking delays during the course of treatment. © 2016 John Wiley & Sons Australia, Ltd.

  15. Research on Effect of Radar Fixing Error in Navigation on Delay of Plane Flow

    NASA Astrophysics Data System (ADS)

    Zhang, Yi; Chang, Leilei; Cao, Jiping; Ling, Xiaodong; Wang, Wei

    2016-02-01

    Fixing error of radar introduces some deviation into measuring value from the true. Regular interval between consecutive planes must be extended to accommodate air traffic control regulation. Mathematical relationship between fixing error and buffer time was deduced. Then, the variation of plane flow delay was researched in different condition of fixing error by means of simulation and practical calculation. It is shown that the effect of fixing error on plane flow delay is apparent compared with the determined situation. Also, the amount of delay is not only related to fixing error but also to average arrival rate. So, the fixing error factor should be considered when scheduling and delay analyzing is implemented. At the same time, it is indicated that decreasing the radar detecting error is necessary to reduce the plane flow delay.

  16. Bubbling effect in the electro-optic delayed feedback oscillator coupled network

    NASA Astrophysics Data System (ADS)

    Liu, Lingfeng; Lin, Jun; Miao, Suoxia

    2017-03-01

    Synchronization in the optical systems coupled network always suffers from bubbling events. In this paper, we numerically investigate the statistical properties of the synchronization characteristics and bubbling effects in the electro-optic delayed feedback oscillator coupled network with different coupling strength, delay time and gain coefficient. Furthermore, we compare our results with the synchronization properties of semiconductor laser (SL) coupled network, which indicates that the electro-optic delayed feedback oscillator can be better to suppress the bubbling effects in the synchronization of coupled network under the same conditions.

  17. Semantic effects in sentence recall: the contribution of immediate vs delayed recall in language assessment.

    PubMed

    Polišenská, Kamila; Chiat, Shula; Comer, Amanda; McKenzie, Kirsty

    2014-01-01

    Sentence recall is increasingly used to assess language. It is widely debated what the task is actually testing, but one rarely explored aspect is the contribution of semantics to sentence recall. The few studies that have examined the role of semantics in sentence recall have employed an 'intrusion paradigm', following Potter and Lombardi (1990), and their paradigm relies on interference errors with conclusions based on an analysis of error patterns. We have instead manipulated the semantic plausibility of whole sentences to investigate the effects of semantics on immediate and delayed sentence recall. In Study 1, adults recalled semantically plausible and implausible sentences either immediately or after distracter tasks varying in lexical retrieval demands (backward counting and picture naming). Results revealed significant effects of plausibility, delay, and a significant interaction indicating increasing reliance on semantics as the demands of the distracter tasks increased. Study 2, conducted with 6-year-old children, employed delay conditions that were modified to avoid floor effects (delay with silence and forward counting) and a similar pattern of results emerged. This novel methodology provided robust evidence showing the effectiveness of delayed recall in the assessment of semantics and the effectiveness of immediate recall in the assessment of morphosyntax. The findings from our study clarify the linguistic mechanisms involved in immediate and delayed sentence recall, with implications for the use of recall tasks in language assessment. The reader will be able to: (i) define the difference between immediate and delayed sentence recall and different types of distractors, (ii) explain the utility of immediate and delayed recall sentence recall in language assessment, (iii) discuss suitability of delayed recall for the assessment of semantics. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Effect of coefficient changes on stability of linear retarded systems with constant time delays

    NASA Technical Reports Server (NTRS)

    Barker, L. K.

    1977-01-01

    A method is developed to determine the effect of coefficient changes on the stability of a retarded system with constant time delays. The method, which uses the tau-decomposition method of stability analysis, is demonstrated by an example.

  19. Design and analysis of clinical trials in the presence of delayed treatment effect.

    PubMed

    Sit, Tony; Liu, Mengling; Shnaidman, Michael; Ying, Zhiliang

    2016-05-20

    In clinical trials with survival endpoint, it is common to observe an overlap between two Kaplan-Meier curves of treatment and control groups during the early stage of the trials, indicating a potential delayed treatment effect. Formulas have been derived for the asymptotic power of the log-rank test in the presence of delayed treatment effect and its accompanying sample size calculation. In this paper, we first reformulate the alternative hypothesis with the delayed treatment effect in a rescaled time domain, which can yield a simplified sample size formula for the log-rank test in this context. We further propose an intersection-union test to examine the efficacy of treatment with delayed effect and show it to be more powerful than the log-rank test. Simulation studies are conducted to demonstrate the proposed methods. Copyright © 2016 John Wiley & Sons, Ltd.

  20. Effects of intrinsic stochasticity on delayed reaction-diffusion patterning systems.

    PubMed

    Woolley, Thomas E; Baker, Ruth E; Gaffney, Eamonn A; Maini, Philip K; Seirin-Lee, Sungrim

    2012-05-01

    Cellular gene expression is a complex process involving many steps, including the transcription of DNA and translation of mRNA; hence the synthesis of proteins requires a considerable amount of time, from ten minutes to several hours. Since diffusion-driven instability has been observed to be sensitive to perturbations in kinetic delays, the application of Turing patterning mechanisms to the problem of producing spatially heterogeneous differential gene expression has been questioned. In deterministic systems a small delay in the reactions can cause a large increase in the time it takes a system to pattern. Recently, it has been observed that in undelayed systems intrinsic stochasticity can cause pattern initiation to occur earlier than in the analogous deterministic simulations. Here we are interested in adding both stochasticity and delays to Turing systems in order to assess whether stochasticity can reduce the patterning time scale in delayed Turing systems. As analytical insights to this problem are difficult to attain and often limited in their use, we focus on stochastically simulating delayed systems. We consider four different Turing systems and two different forms of delay. Our results are mixed and lead to the conclusion that, although the sensitivity to delays in the Turing mechanism is not completely removed by the addition of intrinsic noise, the effects of the delays are clearly ameliorated in certain specific cases.

  1. Diversity begets diversity? The effects of board composition on the appointment and success of women CEOs.

    PubMed

    Cook, Alison; Glass, Christy

    2015-09-01

    Previous research on the effects of leadership diversity on firm outcomes has produced inconsistent and inconclusive findings. While some scholars argue that diversity increases organizational equity and enhances performance, others argue that diversity increases conflict, reduces cooperation and harms performance. This study tests the impact of a variety of compositional factors on firm outcomes. Specifically, we analyze whether and how board composition affects the advancement and mobility of women CEOs and firm performance. Our analysis relies on a unique data set of all Chief Executive Officers (CEOs) and Board of Directors (BODs) in Fortune 500 companies over a ten-year period. We find a marginally significant positive relationship between board diversity and the likelihood of a woman being appointed CEO. We further find that board diversity significantly and positively influences the post-promotion success of women CEOs. Our findings suggest that board composition is critical for the appointment and success of women CEOs, and increasing board diversity should be central to any organizational diversity efforts.

  2. Effect of delay of reinforcement on superstitious inferences.

    PubMed

    Rudski, J M

    2000-06-01

    Temporal contiguity is positively associated with ease of detecting contingencies. When actions and outcomes are not contiguous, intervening responses might be strengthened by adventitious reinforcement. In the current study, participants engaged in a task where pressing 1 of 10 keys was reinforced either immediately or after various delays. Outcomes were scheduled either according to an FR 1 or FR 2 schedule. Participants also answered a question designed to assess their illusion of control. As the latency between the instrumental response and the reinforcer increased, participants attributed less importance to the instrumental response, attributed more importance to other nonessential responses, and began to show stereotyped patterns of responding. The illusion of control was positively related to the intricacy of such patterns. Results are discussed in terms of a contiguity which implies causality heuristic and the relationship of superstition with adventitious reinforcement and illusion of control.

  3. Effects of diversity on multiagent systems: Minority games

    NASA Astrophysics Data System (ADS)

    Wong, K. Y. Michael; Lim, S. W.; Gao, Zhuo

    2005-06-01

    We consider a version of large population games whose agents compete for resources using strategies with adaptable preferences. The games can be used to model economic markets, ecosystems, or distributed control. Diversity of initial preferences of strategies is introduced by randomly assigning biases to the strategies of different agents. We find that diversity among the agents reduces their maladaptive behavior. We find interesting scaling relations with diversity for the variance and other parameters such as the convergence time, the fraction of fickle agents, and the variance of wealth, illustrating their dynamical origin. When diversity increases, the scaling dynamics is modified by kinetic sampling and waiting effects. Analyses yield excellent agreement with simulations.

  4. Plant diversity effects on root decomposition in grasslands

    NASA Astrophysics Data System (ADS)

    Chen, Hongmei; Mommer, Liesje; van Ruijven, Jasper; de Kroon, Hans; Gessler, Arthur; Scherer-Lorenzen, Michael; Wirth, Christian; Weigelt, Alexandra

    2016-04-01

    Loss of plant diversity impairs ecosystem functioning. Compared to other well-studied processes, we know little about whether and how plant diversity affects root decomposition, which is limiting our knowledge on biodiversity-carbon cycling relationships in the soil. Plant diversity potentially affects root decomposition via two non-exclusive mechanisms: by providing roots of different substrate quality and/or by altering the soil decomposition environment. To disentangle these two mechanisms, three decomposition experiments using a litter-bag approach were conducted on experimental grassland plots differing in plant species richness, functional group richness and functional group composition (e.g. presence/absence of grasses, legumes, small herbs and tall herbs, the Jena Experiment). We studied: 1) root substrate quality effects by decomposing roots collected from the different experimental plant communities in one common plot; 2) soil decomposition environment effects by decomposing standard roots in all experimental plots; and 3) the overall plant diversity effects by decomposing community roots in their 'home' plots. Litter bags were installed in April 2014 and retrieved after 1, 2 and 4 months to determine the mass loss. We found that mass loss decreased with increasing plant species richness, but not with functional group richness in the three experiments. However, functional group presence significantly affected mass loss with primarily negative effects of the presence of grasses and positive effects of the presence of legumes and small herbs. Our results thus provide clear evidence that species richness has a strong negative effect on root decomposition via effects on both root substrate quality and soil decomposition environment. This negative plant diversity-root decomposition relationship may partly account for the positive effect of plant diversity on soil C stocks by reducing C loss in addition to increasing primary root productivity. However, to fully

  5. Are Tree Species Diversity and Genotypic Diversity Effects on Insect Herbivores Mediated by Ants?

    PubMed

    Campos-Navarrete, María José; Abdala-Roberts, Luis; Munguía-Rosas, Miguel A; Parra-Tabla, Víctor

    2015-01-01

    Plant diversity can influence predators and omnivores and such effects may in turn influence herbivores and plants. However, evidence for these ecological feedbacks is rare. We evaluated if the effects of tree species (SD) and genotypic diversity (GD) on the abundance of different guilds of insect herbivores associated with big-leaf mahogany (Swietenia macrophylla) were contingent upon the protective effects of ants tending extra-floral nectaries of this species. This study was conducted within a larger experiment consisting of mahogany monocultures and species polycultures of four species and -within each of these two plot types- mahogany was represented by either one or four maternal families. We selected 24 plots spanning these treatment combinations, 10 mahogany plants/plot, and within each plot experimentally reduced ant abundance on half of the selected plants, and surveyed ant and herbivore abundance. There were positive effects of SD on generalist leaf-chewers and sap-feeders, but for the latter group this effect depended on the ant reduction treatment: SD positively influenced sap-feeders under ambient ant abundance but had no effect when ant abundance was reduced; at the same time, ants had negative effects on sap feeders in monoculture but no effect in polyculture. In contrast, SD did not influence specialist stem-borers or leaf-miners and this effect was not contingent upon ant reduction. Finally, GD did not influence any of the herbivore guilds studied, and such effects did not depend on the ant treatment. Overall, we show that tree species diversity influenced interactions between a focal plant species (mahogany) and ants, and that such effects in turn mediated plant diversity effects on some (sap-feeders) but not all the herbivores guilds studied. Our results suggest that the observed patterns are dependent on the combined effects of herbivore identity, diet breadth, and the source of plant diversity.

  6. Are Tree Species Diversity and Genotypic Diversity Effects on Insect Herbivores Mediated by Ants?

    PubMed Central

    Campos-Navarrete, María José; Abdala-Roberts, Luis; Munguía-Rosas, Miguel A.; Parra-Tabla, Víctor

    2015-01-01

    Plant diversity can influence predators and omnivores and such effects may in turn influence herbivores and plants. However, evidence for these ecological feedbacks is rare. We evaluated if the effects of tree species (SD) and genotypic diversity (GD) on the abundance of different guilds of insect herbivores associated with big-leaf mahogany (Swietenia macrophylla) were contingent upon the protective effects of ants tending extra-floral nectaries of this species. This study was conducted within a larger experiment consisting of mahogany monocultures and species polycultures of four species and –within each of these two plot types– mahogany was represented by either one or four maternal families. We selected 24 plots spanning these treatment combinations, 10 mahogany plants/plot, and within each plot experimentally reduced ant abundance on half of the selected plants, and surveyed ant and herbivore abundance. There were positive effects of SD on generalist leaf-chewers and sap-feeders, but for the latter group this effect depended on the ant reduction treatment: SD positively influenced sap-feeders under ambient ant abundance but had no effect when ant abundance was reduced; at the same time, ants had negative effects on sap feeders in monoculture but no effect in polyculture. In contrast, SD did not influence specialist stem-borers or leaf-miners and this effect was not contingent upon ant reduction. Finally, GD did not influence any of the herbivore guilds studied, and such effects did not depend on the ant treatment. Overall, we show that tree species diversity influenced interactions between a focal plant species (mahogany) and ants, and that such effects in turn mediated plant diversity effects on some (sap-feeders) but not all the herbivores guilds studied. Our results suggest that the observed patterns are dependent on the combined effects of herbivore identity, diet breadth, and the source of plant diversity. PMID:26241962

  7. Effects of Diversity Experiences on Critical Thinking Skills: Who Benefits?

    ERIC Educational Resources Information Center

    Loes, Chad; Pascarella, Ernest; Umbach, Paul

    2012-01-01

    This study analyzed data from the Wabash National Study of Liberal Arts Education to estimate the unique effects of exposure to classroom diversity and involvement in interactional diversity on growth in critical thinking skills during the first year of college. Net of important confounding influences, neither classroom nor interactional diversity…

  8. Adapting Strategies of Effective Instruction for Culturally Diverse Preschoolers

    ERIC Educational Resources Information Center

    Yamauchi, Lois A.; Im, Seongah; Schonleber, Nanette S.

    2012-01-01

    This article describes collaboration between preschool and university educators focused on adapting the Center for Research on Education, Diversity, and Excellence (CREDE) standards for Effective Pedagogy for use in early childhood (EC) settings. The CREDE standards are strategies of best practices for culturally diverse K-12 students. Teachers…

  9. Effects of Diversity Experiences on Critical Thinking Skills: Who Benefits?

    ERIC Educational Resources Information Center

    Loes, Chad; Pascarella, Ernest; Umbach, Paul

    2012-01-01

    This study analyzed data from the Wabash National Study of Liberal Arts Education to estimate the unique effects of exposure to classroom diversity and involvement in interactional diversity on growth in critical thinking skills during the first year of college. Net of important confounding influences, neither classroom nor interactional diversity…

  10. Can Ethnic Diversity Have a Positive Effect on School Achievement?

    ERIC Educational Resources Information Center

    Maestri, Virginia

    2017-01-01

    This study investigates the impact of ethnic diversity on test scores, on top of the effect of the share of non-native pupils. We use a rich survey of Dutch primary school students and exploit variations between subsequent cohorts within the same school as our identification strategy. We find that ethnic diversity has a positive impact on the test…

  11. Population of North American elk: effects on plant diversity

    Treesearch

    Kelley M. Stewart; R. Terry Bowyer; John G. Kier; Brian L. Dick; Roger W. Ruess

    2009-01-01

    We tested for indirect effects of population density of large herbivores on plant species richness and diversity in a montane ecosystem, where increased net aboveground primary productivity (NAPP) in response to low levels of herbivory has been reported. We documented a positive, linear relationship between plant-species diversity and richness with NAPP. Structural...

  12. Atmospheric anisotropy and its effect on the delay power spectra of tropospheric scatter radio signals

    NASA Astrophysics Data System (ADS)

    Ibrahim, H. M.

    The atmospheric anisotropy and its effect on the delay power spectra of signals received on troposcatter radio links were studied. A simplified model for determining an anisotropy coefficient is suggested. Theoretical and measured anisotropy profiles are utilized in the calculations of the delay power spectra of tropospheric links. The impact of the anisotropy on the troposcatter channel as a communication link is studied. Bello's model for the troposcatter channel is modified to include the effect of the anisotropy on the delay power spectra. Several theoretical anisotropy profiles based on the experimental observations and the corresponding spectra are evaluated. It was found that the anisotropy results in increased multipath spread and mean delay parameters. This has a direct effect on the irreducible bit error rate (BER) due to intermodulation distortion. Calculations indicate that an order of magnitude increase in the BER due to the atmospheric anisotropy could result.

  13. Prescription Drug Marketing Act of 1987; Prescription Drug Amendments of 1992; policies, requirements, and administrative procedures; delay of effective date. Final rule; delay of effective date.

    PubMed

    2004-02-23

    The Food and Drug Administration (FDA) is further delaying, until December 1, 2006, the effective date of certain requirements of a final rule published in the Federal Register of December 3, 1999 (64 FR 67720). In the Federal Register of May 3, 2000 (65 FR 25639), the agency delayed until October 1, 2001, the effective date of certain requirements in the final rule relating to wholesale distribution of prescription drugs by distributors that are not authorized distributors of record, and distribution of blood derivatives by entities that meet the definition of a "health care entity" in the final rule. The agency further delayed the effective date of these requirements in three subsequent Federal Register notices. Most recently, in the Federal Register of January 31, 2003 (68 FR 4912), FDA delayed the effective date until April 1, 2004. This action further delays the effective date of these requirements until December 1, 2006. The final rule implements the Prescription Drug Marketing Act of 1987 (PDMA), as modified by the Prescription Drug Amendments of 1992 (PDA), and the Food and Drug Administration Modernization Act of 1997 (the Modernization Act). The agency is taking this action to address concerns about the requirements in the final rule raised by affected parties. As explained in the SUPPLEMENTARY INFORMATION section, FDA is working with stakeholders through its counterfeit drug initiative to facilitate widespread, voluntary adoption of track and trace technologies that will generate a de facto electronic pedigree, including prior transaction history back to the original manufacturer, as a routine course of business. If this technology is widely adopted, it is expected to help fulfill the pedigree requirements of the PDMA and obviate or resolve many of the concerns that have been raised with respect to the final rule by ensuring that an electronic pedigree travels with a drug product at all times. Therefore, it is necessary to delay the effective date of Sec

  14. Developmental mechanisms for suppressing the effects of delayed release at the endbulb of Held.

    PubMed

    Yang, Hua; Xu-Friedman, Matthew A

    2010-08-25

    Delayed release of neurotransmitter, also called asynchronous release, is commonly observed at synapses, yet its influence on transmission of spike information is unknown. We examined this issue at endbulb of Held synapses, which are formed by auditory nerve fibers onto bushy cells in the cochlear nucleus. Endbulbs from CBA/CaJ mice aged P6-P49 showed prominent delayed release when driven at physiologically relevant rates. In bushy cells from mice before the onset of hearing (P6-P12), spikes were driven by delayed release up to 100 ms after presynaptic activity. However, no such spikes were observed in bushy cells from mice after the onset of hearing (>P14). Dynamic-clamp experiments indicated that delayed release can drive spikes in older bushy cells provided synchronous release is absent, suggesting that activity normally suppresses these spikes. Application of apamin or alpha-dendrotoxin revealed late spikes in older bushy cells, suggesting that postsynaptic activation of K(V)1.x and SK channels during spiking suppresses the subsequent effects of delayed release. The developmental upregulation of these potassium channels would be highly adaptive for temporally precise auditory processing. Furthermore, delayed release appeared to influence synchronous neurotransmitter release. Enhancement of delayed release using strontium was correlated with lower firing probability in current clamp and smaller synchronous EPSCs in voltage clamp. EGTA-AM had the opposite effects. These effects were consistent with delayed and synchronous release competing for a single vesicle pool. Thus delayed release apparently has negative presynaptic and postsynaptic consequences at the endbulb, which are partly mitigated by postsynaptic potassium channel expression.

  15. Effects of Group I metabotropic glutamate receptor antagonists on sensitivity to reinforcer magnitude and delayed reinforcement in a delay-discounting task in rats: Contribution of delay presentation order.

    PubMed

    Yates, Justin R; Rogers, Katherine K; Gunkel, Benjamin T; Prior, Nicholas A; Hughes, Mallory N; Sharpe, Sara M; Campbell, Hunter L; Johnson, Anthony B; Keller, Margaret G; Breitenstein, Kerry A; Shults, Hansen N

    2017-03-30

    Metabotropic glutamate receptor 1 (mGluR1) blockade has been shown to decrease impulsive choice, as measured in delay discounting. However, several variables are known to influence an animal's discounting, including sensitivity to delayed reinforcement and sensitivity to reinforcer magnitude. The goal of this experiment was to determine the effects of mGluR1, as well as mGluR5, antagonism on these parameters. Forty Sprague Dawley rats were trained in delay discounting, in which consistently choosing a small, immediate reward reflects impulsive choice. For half of the rats, the delay to the large reinforcer increased across blocks of trials, whereas the delay decreased across the session for half of the rats. Following training, half of the rats received injections of the mGluR1 antagonist JNJ 16259685 (JNJ; 0, 0.1, 0.3, or 1.0mg/kg; i.p), and half received injections of the mGluR5 antagonist MPEP (0, 1.0, 3.0, or 10.0mg/kg; i.p.). Administration of JNJ increased sensitivity to delayed reinforcement (i.e., promoted impulsive choice), regardless of which schedule was used. However, the order in which delays were presented modulated the effects of JNJ on sensitivity to reinforcer magnitude. Specifically, JNJ decreased sensitivity to reinforcer magnitude in rats trained on the descending schedule only. MPEP did not alter sensitivity to reinforcer magnitude or sensitivity to delayed reinforcement. These results show that mGluR1 is an important mediator of impulsive choice, and they provide further evidence that delay order presentation is an important variable that influences drug effects in delay discounting.

  16. Effects of asymmetry, transmission delay and noises on the stability of an elementary electricity network

    NASA Astrophysics Data System (ADS)

    Dongmo, Eric Donald; Woafo, Paul

    2015-07-01

    We numerically study the effects of the asymmetry of the transmission lines capabilities, of the transmission delay and power noises, on the stability of an elementary electricity network consisting of one machine and two generators. It is found that the asymmetry increases the stability of the system. It is also found that the threshold value of the perturbation intensity leading to the network instability decreases as the time delay increases. When the system is subject to a stochastic perturbation, its stability depends not only on the noises intensity, but also on the time delay and the value of the transmission lines capabilities.

  17. Delay discounting of hypothetical and real money: the effect of holding reinforcement rate constant.

    PubMed

    Dixon, Mark R; Lik, Nicholas Mui Ker; Green, Leonard; Myerson, Joel

    2013-01-01

    We examined the effect of holding reinforcement rate constant on delay discounting of hypothetical and real money when delays were actually experienced. In some conditions, participants were required to wait for the delayed rewards, and in some conditions, reinforcement rate was held constant by adding blackout periods after immediate rewards. Typical discounting occurred with the standard procedure and when there were no blackouts, but not when we held rate of reinforcement constant. Real and hypothetical money produced the same outcomes. © Society for the Experimental Analysis of Behavior.

  18. Self-regulation strategies may enhance the acute effect of exercise on smoking delay.

    PubMed

    Hatzigeorgiadis, Antonis; Pappa, Vassiliki; Tsiami, Anastasia; Tzatzaki, Theodora; Georgakouli, Kalliopi; Zourbanos, Nikos; Goudas, Marios; Chatzisarantis, Nikos; Theodorakis, Yannis

    2016-06-01

    The present study examined the acute effect of a moderate intensity aerobic exercise session combined with self-regulation on smoking delay in physically inactive smokers. Participants were 11 adults (5 males and 6 females) that completed three experimental conditions: control, exercise, and exercise using self-regulation strategies (SR). Following the experimental treatment smoking for the two exercise conditions delayed significantly more than for the control condition; in addition exercise SR delayed smoking marginally more that the plain exercise condition. Findings supported previous research that acute exercise reduces cravings to smoke, and suggests that the use of self-regulation strategies may strengthen exercise for smoking cessation interventions.

  19. Marginal zone B cell enrichment and strong follicular B cell reduction correlate with a delayed IgG response in a light chain diversity restricted mouse model.

    PubMed

    Amrani, Yacine M; Voegtlé, Danielle; Barbier, Eliane; Six, Adrien; Cazenave, Pierre-André

    2004-10-01

    Recently developed B6.kappa(-)lambda(SEG) mice (by crossing kappa(-) and C57BL/6 mice congenic for the wild Mus spretus SEG strain lambda locus lacking genes coding for lambda1 and lambda3) have a very reduced light chain diversity. B6.kappa(-)lambda(SEG) mice produce only lambda2 and lambdax light chains. Regardless of their Igh haplotype, B6.kappa(-)lambda(SEG) mice show a restricted B cell distribution by light chain subtype with lambdax dominance in all peripheral compartments except peritoneal cavity where lambda2 is dominant. This distribution suggests that selection mechanisms act differently in different B cell compartments on lambda2 and lambdax bearing B cells. Sequence analysis before or following immunization did not reveal unusual mechanisms of diversification. B6.kappa(-)lambda(SEG) mice still respond to various challenging antigens using new Ab patterns. In particular, regardless of Igh(a) or Igh(b) haplotypes, the anti-2,4-dinitrophenyl response is characterized by a restricted diversity for both heavy and light chains and a delayed IgG response when compared to B6 and B6.kappa(-) mice. We suggest that the delayed IgG response is due to the expansion of marginal zone B cells whereas follicular B cells are strongly reduced.

  20. Effect of phase response curve skew on synchronization with and without conduction delays

    PubMed Central

    Canavier, Carmen C.; Wang, Shuoguo; Chandrasekaran, Lakshmi

    2013-01-01

    A central problem in cortical processing including sensory binding and attentional gating is how neurons can synchronize their responses with zero or near-zero time lag. For a spontaneously firing neuron, an input from another neuron can delay or advance the next spike by different amounts depending upon the timing of the input relative to the previous spike. This information constitutes the phase response curve (PRC). We present a simple graphical method for determining the effect of PRC shape on synchronization tendencies and illustrate it using type 1 PRCs, which consist entirely of advances (delays) in response to excitation (inhibition). We obtained the following generic solutions for type 1 PRCs, which include the pulse-coupled leaky integrate and fire model. For pairs with mutual excitation, exact synchrony can be stable for strong coupling because of the stabilizing effect of the causal limit region of the PRC in which an input triggers a spike immediately upon arrival. However, synchrony is unstable for short delays, because delayed inputs arrive during a refractory period and cannot trigger an immediate spike. Right skew destabilizes antiphase and enables modes with time lags that grow as the conduction delay is increased. Therefore, right skew favors near synchrony at short conduction delays and a gradual transition between synchrony and antiphase for pairs coupled by mutual excitation. For pairs with mutual inhibition, zero time lag synchrony is stable for conduction delays ranging from zero to a substantial fraction of the period for pairs. However, for right skew there is a preferred antiphase mode at short delays. In contrast to mutual excitation, left skew destabilizes antiphase for mutual inhibition so that synchrony dominates at short delays as well. These pairwise synchronization tendencies constrain the synchronization properties of neurons embedded in larger networks. PMID:24376399

  1. The effects of long delay and transmission errors on the performance of TP-4 implementations

    NASA Technical Reports Server (NTRS)

    Durst, Robert C.; Evans, Eric L.; Mitchell, Randy C.

    1991-01-01

    A set of tools that allows us to measure and examine the effects of transmission delay and errors on the performance of TP-4 implementations has been developed. The tools give insight into both the large- and small-scale behaviors of an implementation. These tools have been systematically applied to a commercial implementation of TP-4. Measurements show, among other things, that a 2-second one-way transmission delay and an effective bit-error rate of 1 error per 100,000 bits can result in a 95 percent reduction in TP-4 throughput. The detailed statistics give insight into why transmission delay and errors affect this implementations so significantly and support a number of 'lessons learned' that could be applied to TP-4 implementations that operate more robustly across networks with long transmission delays and transmission errors.

  2. Effects of time delay and pitch control sensitivity in the flared landing

    NASA Technical Reports Server (NTRS)

    Berthe, C. J.; Chalk, C. R.; Wingarten, N. C.; Grantham, W.

    1986-01-01

    Between December 1985 and January 1986, a flared landing program was conducted, using the USAF Total In-Flight simulator airplane, to examine time delay effects in a formal manner. Results show that as pitch sensitivity is increased, tolerance to time delay decreases. With the proper selection of pitch sensitivity, Level I performance was maintained with time delays ranging from 150 milliseconds to greater than 300 milliseconds. With higher sensitivity, configurations with Level I performance at 150 milliseconds degraded to level 2 at 200 milliseconds. When metrics of time delay and pitch sensitivity effects are applied to enhance previously developed predictive criteria, the result is an improved prediction technique which accounts for significant closed loop items.

  3. Effects of time delay and pitch control sensitivity in the flared landing

    NASA Technical Reports Server (NTRS)

    Berthe, C. J.; Chalk, C. R.; Wingarten, N. C.; Grantham, W.

    1986-01-01

    Between December 1985 and January 1986, a flared landing program was conducted, using the USAF Total In-Flight simulator airplane, to examine time delay effects in a formal manner. Results show that as pitch sensitivity is increased, tolerance to time delay decreases. With the proper selection of pitch sensitivity, Level I performance was maintained with time delays ranging from 150 milliseconds to greater than 300 milliseconds. With higher sensitivity, configurations with Level I performance at 150 milliseconds degraded to level 2 at 200 milliseconds. When metrics of time delay and pitch sensitivity effects are applied to enhance previously developed predictive criteria, the result is an improved prediction technique which accounts for significant closed loop items.

  4. The Effect of Concurrent Semantic Categorization on Delayed Serial Recall

    PubMed Central

    Acheson, Daniel J.; MacDonald, Maryellen C.; Postle, Bradley R.

    2010-01-01

    The influence of semantic processing on the serial ordering of items in short-term memory was explored using a novel dual-task paradigm. Subjects engaged in two picture judgment tasks while simultaneously performing delayed serial recall. List material varied in the presence of phonological overlap (Experiments 1 and 2) and in semantic content (concrete words in Experiment 1 and 3; nonwords in Experiments 2 and 3). Picture judgments varied in the extent to which they required accessing visual semantic information (i.e., semantic categorization and line orientation judgments). Results showed that, relative to line orientation judgments, engaging in semantic categorization judgments increased the proportion of item ordering errors for concrete lists but did not affect error proportions for nonword lists. Furthermore, although more ordering errors were observed for phonologically similar relative to dissimilar lists, no interactions were observed between the phonological overlap and picture judgment task manipulations. These results thus demonstrate that lexical-semantic representations can affect the serial ordering of items in short-term memory. Furthermore, the dual-task paradigm provides a new method for examining when and how semantic representations affect memory performance. PMID:21058880

  5. The effects of three modalities on delayed onset muscle soreness.

    PubMed

    Weber, M D; Servedio, F J; Woodall, W R

    1994-11-01

    Delayed onset muscle soreness is a common problem that can interfere with rehabilitation as well as activities of daily living. The purpose of this study was to test the impact of therapeutic massage, upper body ergometry, or microcurrent electrical stimulation on muscle soreness and force deficits evident following a high-intensity eccentric exercise bout. Forty untrained, volunteer female subjects were randomly assigned to one of three treatment groups or to a control group. Exercise consisted of high-intensity eccentric contractions of the elbow flexors. Resistance was reduced as subjects fatigued, until they reached exhaustion. Soreness rating was determined using a visual analog scale. Force deficits were determined by measures of maximal voluntary isometric contraction at 90 degrees of elbow flexion and peak torque for elbow flexion at 60 degrees/sec on a Cybex II isokinetic dynamometer. Maximal voluntary isometric contraction and peak torque were determined at the 0 hour (before exercise) and again at 24 and 48 hours postexercise. Treatments were applied immediately following exercise and again at 24 hours after exercise. The control group subjects rested following their exercise bout. Statistical analysis showed significant increases in soreness rating and significant decreases in force generated when the 0 hour was compared with 24- and 48-hour measures. Further analysis indicated no statistically significant differences between massage, microcurrent electrical stimulation, upper body ergometry, and control groups.

  6. The effects of ice massage on delayed muscle soreness.

    PubMed

    Yackzan, L; Adams, C; Francis, K T

    1984-01-01

    The following hypotheses were tested in the present study: (1) cryotherapy would reduce delayed muscle soreness (DMS) in eccentrically exercised muscles; (2) early cold treatment would reduce this soreness more than later postexercise treatment times; and (3) joint range of motion (ROM) would be inversely related to the subjective soreness ratings. Subjective sensations of muscular soreness and changes in elbow joint ROM were assessed in 30 subjects at 0, 24, 48, and 72 hours following eccentric-biased exercise in the elbow flexors. Cold treatments were applied immediately, 24 or 48 hours following a single exercise session. In response to the eccentric exercise, significant muscle soreness increases and elbow ROM decreases were observed in all exercised muscles from 24 to 48 hours postexercise. No differences in muscle soreness or elbow ROM changes were observed between treated and untreated arms except for one. Subjects treated at 24 hours postexercise reported greater soreness in their arms compared to untreated arms just prior to treatment (24 hour postexercise). The results do not support the efficacy of cold in reducing DMS. A negative correlation between muscle soreness and elbow ROM at 48 and 72 hours postexercise indicated that an increase in soreness was associated with a decrease in ROM.

  7. Effect of delayed evisceration on the microbial quality of meat.

    PubMed

    Gill, C O; Penney, N; Nottingham, P M

    1976-04-01

    The postomortem invasion of muscle and other tissues by bacteria from the intestinal tract was studied with the use of radioactive tracers. The injection of 14C-labeled bacteria or spores into the intestines of guinea pig carcasses within 24 h of death resulted in the rapid spread of 14C throughout carcasses. When live bacteria were injected along with the labeled cells, it was not possible to isolate viable organisms from the body tissues if the living animal had been exposed to the bacteria. It appears that animals are immune to their normal intestinal flora and that this immunity persists after death; thus passage of these bacteria into the lymphatic system does not necessarily result in the presence of live bacteria in carcass tissues. It therefore seems that a delay of up to 24 h before evisceration would not lead to deep tissue contamination of the carcass by organisms usually present in the intestines. Further evidence for this hypothesis was obtained by showing that muscle and lymph nodes from uneviscerated lamb carcasses hung for 24 h at 20 C remained sterile.

  8. Posttraumatic Stress, Coping Flexibility, and Risky Drinking Among Trauma-Exposed Male and Female College Students: The Mediating Effect of Delay of Gratification.

    PubMed

    Boyraz, Güler; Cherry, Megan L; Cherry, Marcus A; Aarstad-Martin, Samantha; Cloud, Cody; Shamp, Lindsey M

    2017-08-31

    The co-occurence of posttraumatic stress (PTS) and risky drinking has been demonstrated in diverse populations, including college students. However, the mechanisms underlying this co-occurrence, as well as the protective factors that may reduce risky drinking among trauma-exposed college students have yet to be fully understood in the literature. The present study builds upon self-regulation theories and previous empirical work to determine whether the effects of PTS and coping flexibility on risky drinking were mediated by delay of gratification among trauma-exposed college students. In addition, the potential moderating effect of gender on these relationships was examined. Participants included 624 trauma-exposed college students (68.4% female) attending a public university in the southeast region of the United States. Data were collected through an online survey. The hypothesized model was examined using a multigroup structural equation modeling approach. As hypothesized, PTS had a significant, positive indirect effect on risky drinking through delay of gratification; however, the effect of PTS on delay of gratification was stronger for males than for females. Results also indicated that the indirect effect of coping flexibility on risky drinking through delay of gratification was significant and negative for males and females. Conclusions/Importance: The findings of this study suggest that delay of gratification might be an important mechanism underlying the co-occurrence of PTS and risky drinking. In addition, our results highlight the potential benefits of coping flexibility for college students coping with PTS.

  9. The Effects of Test Trial and Processing Level on Immediate and Delayed Retention

    PubMed Central

    Chang, Sau Hou

    2017-01-01

    The purpose of the present study was to investigate the effects of test trial and processing level on immediate and delayed retention. A 2 × 2 × 2 mixed ANOVAs was used with two between-subject factors of test trial (single test, repeated test) and processing level (shallow, deep), and one within-subject factor of final recall (immediate, delayed). Seventy-six college students were randomly assigned first to the single test (studied the stimulus words three times and took one free-recall test) and the repeated test trials (studied the stimulus words once and took three consecutive free-recall tests), and then to the shallow processing level (asked whether each stimulus word was presented in capital letter or in small letter) and the deep processing level (whether each stimulus word belonged to a particular category) to study forty stimulus words. The immediate test was administered five minutes after the trials, whereas the delayed test was administered one week later. Results showed that single test trial recalled more words than repeated test trial in immediate final free-recall test, participants in deep processing performed better than those in shallow processing in both immediate and delayed retention. However, the dominance of single test trial and deep processing did not happen in delayed retention. Additional study trials did not further enhance the delayed retention of words encoded in deep processing, but did enhance the delayed retention of words encoded in shallow processing. PMID:28344679

  10. The Effects of Test Trial and Processing Level on Immediate and Delayed Retention.

    PubMed

    Chang, Sau Hou

    2017-03-01

    The purpose of the present study was to investigate the effects of test trial and processing level on immediate and delayed retention. A 2 × 2 × 2 mixed ANOVAs was used with two between-subject factors of test trial (single test, repeated test) and processing level (shallow, deep), and one within-subject factor of final recall (immediate, delayed). Seventy-six college students were randomly assigned first to the single test (studied the stimulus words three times and took one free-recall test) and the repeated test trials (studied the stimulus words once and took three consecutive free-recall tests), and then to the shallow processing level (asked whether each stimulus word was presented in capital letter or in small letter) and the deep processing level (whether each stimulus word belonged to a particular category) to study forty stimulus words. The immediate test was administered five minutes after the trials, whereas the delayed test was administered one week later. Results showed that single test trial recalled more words than repeated test trial in immediate final free-recall test, participants in deep processing performed better than those in shallow processing in both immediate and delayed retention. However, the dominance of single test trial and deep processing did not happen in delayed retention. Additional study trials did not further enhance the delayed retention of words encoded in deep processing, but did enhance the delayed retention of words encoded in shallow processing.

  11. Effects of reinforcement rate and delay on the acquisition of lever pressing by rats.

    PubMed Central

    Bruner, C A; Avila, R; Acuña, L; Gallardo, L M

    1998-01-01

    The acquisition of lever pressing by naive rats, in the absence of shaping, was studied as a function of different rates and unsignaled delays of reinforcement. Groups of 3 rats were each exposed to tandem schedules that differed in either the first or the second component. First-component schedules were either continuous reinforcement or random-interval 15, 30, 60 or 120 s; second-component schedules were fixed-time 0, 1, 3, 6, 12, or 24 s. Rate of responding was low under continuous immediate reinforcement and higher under random-interval 15 s. Random interval 30-s and 60-s schedules produced lower rates that were similar to each other. Random-interval 120 s controlled the lowest rate in the immediate-reinforcement condition. Adding a constant 12-s delay to each of the first-component schedule parameters controlled lower response rates that did not vary systematically with reinforcement rate. The continuous and random-interval 60-s schedules of immediate reinforcement controlled higher global and first-component response rates than did the same schedules combined with longer delays, and first-component rates showed some graded effects of delay duration. In addition, the same schedules controlled higher second-component response rates in combination with a 1-s delay than in combination with longer delays. These results were related to those from previous studies on acquisition with delayed reinforcement as well as to those from similar reinforcement procedures used during steady-state responding. PMID:9465413

  12. Effects of time delay on the stochastic resonance in small-world neuronal networks.

    PubMed

    Yu, Haitao; Wang, Jiang; Du, Jiwei; Deng, Bin; Wei, Xile; Liu, Chen

    2013-03-01

    The effects of time delay on stochastic resonance in small-world neuronal networks are investigated. Without delay, an intermediate intensity of additive noise is able to optimize the temporal response of the neural system to the subthreshold periodic signal imposed on all neurons constituting the network. The time delay in the coupling process can either enhance or destroy stochastic resonance of neuronal activity in the small-world network. In particular, appropriately tuned delays can induce multiple stochastic resonances, which appear intermittently at integer multiples of the oscillation period of weak external forcing. It is found that the delay-induced multiple stochastic resonances are most efficient when the forcing frequency is close to the global-resonance frequency of each individual neuron. Furthermore, the impact of time delay on stochastic resonance is largely independent of the small-world topology, except for resonance peaks. Considering that information transmission delays are inevitable in intra- and inter-neuronal communication, the presented results could have important implications for the weak signal detection and information propagation in neural systems.

  13. Impacts of Diversity on Communication Effectiveness: A Proposed Typology.

    ERIC Educational Resources Information Center

    Hopkins, Willie E.; Hopkins, Shirley A.

    1994-01-01

    Proposes a typology of impacts that greater increases in workforce diversity might have on communication effectiveness in organizations. Proposes the typology to stimulate further interest in the research domain. (SR)

  14. Institutions and Cultural Diversity: Effects of Democratic and Propaganda Processes on Local Convergence and Global Diversity

    PubMed Central

    Ulloa, Roberto; Kacperski, Celina; Sancho, Fernando

    2016-01-01

    In a connected world where people influence each other, what can cause a globalized monoculture, and which measures help to preserve the coexistence of cultures? Previous research has shown that factors such as homophily, population size, geography, mass media, and type of social influence play important roles. In the present paper, we investigate for the first time the impact that institutions have on cultural diversity. In our first three studies, we extend existing agent-based models and explore the effects of institutional influence and agent loyalty. We find that higher institutional influence increases cultural diversity, while individuals' loyalty to their institutions has a small, preserving effect. In three further studies, we test how bottom-up and top-down processes of institutional influence impact our model. We find that bottom-up democratic practices, such as referenda, tend to produce convergence towards homogeneity, while top-down information dissemination practices, such as propaganda, further increase diversity. In our last model—an integration of bottom-up and top-down processes into a feedback loop of information—we find that when democratic processes are rare, the effects of propaganda are amplified, i.e., more diversity emerges; however, when democratic processes are common, they are able to neutralize or reverse this propaganda effect. Importantly, our models allow for control over the full spectrum of diversity, so that a manipulation of our parameters can result in preferred levels of diversity, which will be useful for the study of other factors in the future. We discuss possible mechanisms behind our results, applications, and implications for political and social sciences. PMID:27058247

  15. Institutions and Cultural Diversity: Effects of Democratic and Propaganda Processes on Local Convergence and Global Diversity.

    PubMed

    Ulloa, Roberto; Kacperski, Celina; Sancho, Fernando

    2016-01-01

    In a connected world where people influence each other, what can cause a globalized monoculture, and which measures help to preserve the coexistence of cultures? Previous research has shown that factors such as homophily, population size, geography, mass media, and type of social influence play important roles. In the present paper, we investigate for the first time the impact that institutions have on cultural diversity. In our first three studies, we extend existing agent-based models and explore the effects of institutional influence and agent loyalty. We find that higher institutional influence increases cultural diversity, while individuals' loyalty to their institutions has a small, preserving effect. In three further studies, we test how bottom-up and top-down processes of institutional influence impact our model. We find that bottom-up democratic practices, such as referenda, tend to produce convergence towards homogeneity, while top-down information dissemination practices, such as propaganda, further increase diversity. In our last model--an integration of bottom-up and top-down processes into a feedback loop of information--we find that when democratic processes are rare, the effects of propaganda are amplified, i.e., more diversity emerges; however, when democratic processes are common, they are able to neutralize or reverse this propaganda effect. Importantly, our models allow for control over the full spectrum of diversity, so that a manipulation of our parameters can result in preferred levels of diversity, which will be useful for the study of other factors in the future. We discuss possible mechanisms behind our results, applications, and implications for political and social sciences.

  16. Effect of Delayed Cord Clamping on Systemic Blood Flow: A Randomized Controlled Trial.

    PubMed

    Popat, Himanshu; Robledo, Kristy P; Sebastian, Lucille; Evans, Nicholas; Gill, Andrew; Kluckow, Martin; Sinhal, Sanjay; de Waal, Koert; Tarnow-Mordi, William; Osborn, David

    2016-11-01

    To determine whether delayed cord clamping improves systemic blood flow compared with immediate cord clamping in very preterm infants in the first 24 hours. Women delivering at <30 weeks' gestation at 5 tertiary centers were randomized to receive immediate cord clamping (<10 seconds) or delayed cord clamping (≥60 seconds). Echocardiography and cardiorespiratory data were collected at 3, 9, and 24 hours after birth. The primary outcome was mean lowest superior vena cava (SVC) flow. Of 266 infants enrolled, 133 were randomized to immediate cord clamping and 133 to delayed cord clamping. The 2 groups were similar at baseline, including mean gestation (immediate cord clamping 28 weeks vs delayed cord clamping 28 weeks) and birth weight (immediate cord clamping 1003 g vs delayed cord clamping 1044 g). There was no significant difference between groups in the primary outcome of mean lowest SVC flow (immediate cord clamping 71.4 mL/kg/min [SD 28.1] vs delayed cord clamping 70.2 mL/kg/min [SD 26.9]; P = .7). For secondary outcomes, hemoglobin increased by 0.9 g/dL at 6 hours in the group with delayed cord clamping (95% CI 3.9, 14.4; P = .0005, adjusted for baseline). The group with delayed cord clamping had lower right ventricular output (-21.9 mL/kg/min, 95% CI -39.0, -4.7; P = .01). Rates of treated hypotension, ductus arteriosus size and shunt direction, and treatment of the ductus arteriosus were similar. Delayed cord clamping had no effect on systemic blood flow measured as mean lowest SVC flow in the first 24 hours in infants <30 weeks' gestation. Australia New Zealand Clinical Trials Registry: ACTRN12610000633088. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Choice between delayed food and immediate opioids in rats: treatment effects and individual differences.

    PubMed

    Panlilio, Leigh V; Secci, Maria E; Schindler, Charles W; Bradberry, Charles W

    2017-09-04

    Addiction involves maladaptive choice behavior in which immediate drug effects are valued more than delayed nondrug rewards. To model this behavior and extend our earlier work with the prescription opioid oxycodone, we allowed rats to choose between immediate intravenous delivery of the short-acting opioid remifentanil and delayed delivery of highly palatable food pellets. Treatment drugs were tested on a baseline where remifentanil was preferred over food. Treatment with a high dose of the opioid antagonist naltrexone decreased but did not reverse the preference for remifentanil. Treatment with the serotonin 5-HT2C agonist lorcaserin decreased remifentanil and food self-administration nonselectively. Across conditions in which the alternative to delayed food was either a moderate dose of oxycodone, a moderate or high dose of remifentanil, a smaller more immediate delivery of food, or timeout with no primary reinforcement, choice was determined by both the length of the delay and the nature of the alternative option. Delayed food was discounted most steeply when the alternative was a high dose of remifentanil, which was preferred over food when food was delayed by 30 s or more. Within-subject comparisons showed no evidence for trait-like impulsivity or sensitivity to delay across these conditions. Choice was determined more by the current contingencies of reinforcement than by innate individual differences. This finding suggests that people might develop steep delay-discounting functions because of the contingencies in their environment, and it supports the use of contingency management to enhance the relative value of delayed nondrug reinforcers.

  18. Effects of the gaseous and liquid water content of the atmosphere on range delay and Doppler frequency

    NASA Technical Reports Server (NTRS)

    Flock, W. L.

    1981-01-01

    When high precision is required for range measurement on Earth space paths, it is necessary to correct as accurately as possible for excess range delays due to the dry air, water vapor, and liquid water content of the atmosphere. Calculations based on representative values of atmospheric parameters are useful for illustrating the order of magnitude of the expected delays. Range delay, time delay, and phase delay are simply and directly related. Doppler frequency variations or noise are proportional to the time rate of change of excess range delay. Tropospheric effects were examined as part of an overall consideration of the capability of precision two way ranging and Doppler systems.

  19. Glucose-specific signaling effects on delay discounting in intertemporal choice.

    PubMed

    Wang, X T Xiao-Tian; Huangfu, Gang

    2017-02-01

    We propose that decisions related to resource management (e.g., intertemporal choice between a smaller-and-sooner reward and a larger-and-later reward) are sensitive to and regulated by fluctuating blood glucose levels. Circulating glucose affects intertemporal choice by means of signaling body energy condition instead of serving as a replenishing resource for effortful cognitive processing. We intend to dissociate calorie-supplying functions from glucose-unique anticipatory effects on behavioral resource management, measured by delay discounting in making intertemporal choices. Regarding the anticipatory functions of the glucose-insulin system in regulating the degree of delay discounting, we tested three predictions: First, we predict that the signaling effects of circulating glucose on delay discounting do not need to be dose-dependent as long as glucose fluctuation indicates a directional trend in body energy budget. Second, such effects of glucose fluctuation on delay discounting are phagic (appetite related) instead of dipsian (thirst related). Third, this glucose-insulin signaling system requires glucose as the specific input, thus is insensitive to other forms of sugar that are not insulin regulated. In Study 1, fasting participants were randomly assigned to one of five groups: water consumption, zero-consumption, and three glucose consumption (18g, 36g, and 72g cane sugar/250ml water) groups. The participants competed two sets of intertemporal choice questions with varying delay discounting rates before and after a beverage intervention. The results showed that the rate of delay discounting was negatively correlated to blood glucose levels. The effects of circulating glucose on delay discounting closely followed the changes in blood glucose levels showing a plateau on both dose-response curves (i.e., the sugar dose-blood glucose level curve and the sugar does-delay discounting curve). Secondly, the effects of circulating glucose on delay discounting were

  20. Time-delay effects on the aging transition in a population of coupled oscillators.

    PubMed

    Thakur, Bhumika; Sharma, Devendra; Sen, Abhijit

    2014-10-01

    We investigate the influence of time-delayed coupling on the nature of the aging transition in a system of coupled oscillators that have a mix of active and inactive oscillators, where the aging transition is defined as the gradual loss of collective synchrony as the proportion of inactive oscillators is increased. We start from a simple model of two time-delay coupled Stuart-Landau oscillators that have identical frequencies but are located at different distances from the Hopf bifurcation point. A systematic numerical and analytic study delineates the dependence of the critical coupling strength (at which the system experiences total loss of synchrony) on time delay and the average distance of the system from the Hopf bifurcation point. We find that time delay can act to facilitate the aging transition by lowering the threshold coupling strength for amplitude death in the system. We then extend our study to larger systems of globally coupled active and inactive oscillators including an infinite system in the thermodynamic limit. Our model system and results can provide a useful paradigm for understanding the functional robustness of diverse physical and biological systems that are prone to aging transitions.

  1. The effects of the delays on systems subject to manual control

    NASA Technical Reports Server (NTRS)

    Hess, R. A.

    1982-01-01

    Results are presented of an experimental study to determine the effects of time delays in manual control systems. A simple, fixed-base laboratory simulation facility is used for determining pilot dynamics and tracking performance in a series of single-axis, compensatory tracking tasks. In these tasks, three time-delay values and three controlled-element dynamics are used. The delays are chosen to encompass values encountered in experimental and operational aircraft. It is noted that the controlled-element dynamics replicate those found in many previous manual control studies, that is, the classical displacement, rate, and acceleration control systems. The experimental effort is complemented with an analytical pilot modeling study where the parameters of a structural model of the human pilot are adjusted so as to provide excellent matches to the experimentally determined pilot dynamics. The experimental and analytical studies both indicate that time delays cause significant changes in pilot equalization requirements.

  2. Simulation evaluation of the effects of time delay and motion on rotorcraft handling qualities

    NASA Technical Reports Server (NTRS)

    Mitchell, David G.; Hoh, Roger H.; Atencio, Adolph, Jr.; Key, David L.

    1991-01-01

    A study aimed at determining the effects of simulator characteristics on perceived handling qualities is discussed. Evaluations were conducted with a baseline set of rotorcraft dynamics, using a simple transfer-function model of an uncoupled helicopter, under different conditions of visual and overall time delays. As the visual and motion parameters were changed, differences in pilot opinion were found reflecting a change in the pilots' perceptions of handling qualities, rather than changes in the aircraft model itself. It is concluded that it is necessary to tailor the motion washout dynamics to suit the task, with reduced washouts for precision maneuvering as compared to aggressive maneuvering. Visual-delay data suggest that it may be better to allow some time delay in the visual path to minimize the mismatch between visual and motion, rather than eliminate the visual delay entirely through lead compensation.

  3. Simulation evaluation of the effects of time delay and motion on rotorcraft handling qualities

    NASA Technical Reports Server (NTRS)

    Mitchell, David G.; Hoh, Roger H.; Atencio, Adolph, Jr.; Key, David L.

    1991-01-01

    A study aimed at determining the effects of simulator characteristics on perceived handling qualities is discussed. Evaluations were conducted with a baseline set of rotorcraft dynamics, using a simple transfer-function model of an uncoupled helicopter, under different conditions of visual and overall time delays. As the visual and motion parameters were changed, differences in pilot opinion were found reflecting a change in the pilots' perceptions of handling qualities, rather than changes in the aircraft model itself. It is concluded that it is necessary to tailor the motion washout dynamics to suit the task, with reduced washouts for precision maneuvering as compared to aggressive maneuvering. Visual-delay data suggest that it may be better to allow some time delay in the visual path to minimize the mismatch between visual and motion, rather than eliminate the visual delay entirely through lead compensation.

  4. The effect and design of time delay in feedback control for a nonlinear isolation system

    NASA Astrophysics Data System (ADS)

    Sun, Xiuting; Xu, Jian; Fu, Jiangsong

    2017-03-01

    The optimum value of time delay of active control used in a nonlinear isolation system for different types of external excitation is studied in this paper. Based on the mathematical model of the nonlinear isolator with time-delayed active control, the stability, response and displacement transmissibility of the system are analyzed to obtain the standards for appropriate values of time delay and control strengths. The effects of nonlinearity and time delay on the stability and vibration response are discussed in details. For impact excitation and random excitation, the optimal value of time delay is obtained based on the vibration dissipation time via eigenvalues analysis, while for harmonic excitation, the optimal values are determined based on multiple vibration properties including natural frequency, amplitude death region and effective isolation region by the Averaging Method. This paper establishes the relationship between the parameters and vibration properties of a nonlinear isolation system which provides the guidance for optimizing time-delayed active control for different types of excitation in engineering practices.

  5. Effect of unsignaled delays between stimuli in a chain schedule on responding and resistance to change.

    PubMed

    Bell, Matthew C; Gomez, Belen E

    2008-03-01

    Behavioral momentum theory is an evolving theoretical account of the strength of behavior. One challenge for the theory is determining the role of signal stimuli in determining response strength. This study evaluated the effect of an unsignaled delay between the initial link and terminal link of a two-link chain schedule on resistance to change using a multiple schedule of reinforcement. Pigeons were presented two different signaled delay to reinforcement schedules. Both schedules employed a two-link chain schedule with a variable interval 120-s initial link followed by a 5-s fixed time terminal link schedule. One of the schedules included a 5-s unsignaled delay between the initial link and the terminal link. Resistance to change was assessed with two separate disruption procedures: extinction and adding a variable time 20-s schedule of reinforcement to the inter-component interval. Baseline responding was lower in the schedule with the unsignaled delay but resistance to change for the initial link was unaffected by the unsignaled delay. The results suggest that not all unsignaled delays are equal in their effect on resistance to change.

  6. Effects of delayed settlement on post-settlement growth and survival of scleractinian coral larvae.

    PubMed

    Graham, Erin M; Baird, Andrew H; Willis, Bette L; Connolly, Sean R

    2013-10-01

    Demographic connectivity requires both the dispersal of individuals between sub-populations, and their subsequent contribution to population dynamics. For planktonic, non-feeding marine larvae, the capacity to delay settlement enables greater dispersal distances, but the energetic cost of delayed settlement has been shown to adversely impact post-settlement fitness in several taxa. Here, we assess whether delayed settlement influences mortality rates or growth rates for the first 6 weeks following settlement of the scleractinian coral, Acropora tenuis. Coral larvae that were settled at 2, 4, and 6 weeks after spawning, and then deployed in the field, showed negligible effects of delayed settlement on post-settlement survival and time to initial budding for colony formation. Between-cohort differences in budding rate appeared to be explained by temporal variation in the post-settlement acquisition of zooxanthellae. The potential for coral larvae to remain in the pelagic zone for increased periods of time with little to no effect on post-settlement survival and growth suggests that the capacity for delayed settlement is likely to have meaningful demographic consequences for broadcast-spawning reef-building corals, and that the predicted trade-off between delayed settlement and post-settlement fitness is less applicable to reef-building scleractinian corals than other taxa with non-feeding larvae.

  7. Effects of AV-delay optimization on hemodynamic parameters in patients with VDD pacemakers.

    PubMed

    Krychtiuk, Konstantin A; Nürnberg, Michael; Volker, Romana; Pachinger, Linda; Jarai, Rudolf; Freynhofer, Matthias K; Wojta, Johann; Huber, Kurt; Weiss, Thomas W

    2014-05-01

    Atrioventricular (AV) delay optimization improves hemodynamics and clinical parameters in patients treated with cardiac resynchronization therapy and dual-chamber-pacemakers (PM). However, data on optimizing AV delay in patients treated with VDD-PMs are scarce. We, therefore, investigated the acute and chronic effects of AV delay optimization on hemodynamics in patients treated with VDD-PMs due to AV-conduction disturbances. In this prospective, single-center interventional trial, we included 64 patients (38 men, 26 women, median age: 77 (70-82) years) with implanted VDD-PM. AV-delay optimization was performed using a formula based on the surface electrocardiogram (ECG). Hemodynamic parameters (stroke volume (SV), cardiac output (CO), heart rate (HR), and blood pressure (BP)) were measured at baseline and follow-up after 3 months using impedance cardiography. Using an ECG formula for AV-delay optimization, the AV interval was decreased from 180 (180-180) to 75 (75-100) ms. At baseline, AV-delay optimization led to a significant increase of both SV (71.3 ± 15.8 vs. 55.3 ± 12.7 ml, p < 0.001, for optimized AV delay vs. nominal AV interval, respectively) and CO (5.1 ± 1.4 vs. 3.9 ± 1.0 l/min, p < 0.001), while HR and BP remained unchanged. At follow-up, the improvement in CO remained stable (4.9 ± 1.3 l/min, p = 0.09), while SV slightly, but significantly, decreased (to 65.1 ± 17.6, p < 0.01). AV-delay optimization in patients treated with VDD-PMs exhibits immediate beneficial effects on hemodynamic parameters that are sustained for 3 months.

  8. Delayed conifer mortality after fuel reduction treatments: interactive effects of fuel, fire intensity, and bark beetles.

    PubMed

    Youngblood, Andrew; Grace, James B; McIver, James D

    2009-03-01

    Many low-elevation dry forests of the western United States contain more small trees and fewer large trees, more down woody debris, and less diverse and vigorous understory plant communities compared to conditions under historical fire regimes. These altered structural conditions may contribute to increased probability of unnaturally severe wildfires, susceptibility to uncharacteristic insect outbreaks, and drought-related mortality. Broad-scale fuel reduction and restoration treatments are proposed to promote stand development on trajectories toward more sustainable structures. Little research to date, however, has quantified the effects of these treatments on the ecosystem, especially delayed and latent tree mortality resulting directly or indirectly from treatments. In this paper, we explore complex hypotheses relating to the cascade of effects that influence ponderosa pine (Pinus ponderosa) and Douglas-fir (Pseudotsuga menziesii) mortality using structural equation modeling (SEM). We used annual census and plot data through six growing seasons after thinning and four growing seasons after burning from a replicated, operational-scale, completely randomized experiment conducted in northeastern Oregon, USA, as part of the national Fire and Fire Surrogate study. Treatments included thin, burn, thin followed by burn (thin + burn), and control. Burn and thin + burn treatments increased the proportion of dead trees while the proportion of dead trees declined or remained constant in thin and control units, although the density of dead trees was essentially unchanged with treatment. Most of the new mortality (96%) occurred within two years of treatment and was attributed to bark beetles. Bark beetle-caused tree mortality, while low overall, was greatest in thin + burn treatments. SEM results indicate that the probability of mortality of large-diameter ponderosa pine from bark beetles and wood borers was directly related to surface fire severity and bole charring, which

  9. The Effects of Short Interval Delay of Reinforcement Upon Human Discrimination Learning. IMRID Papers and Reports Vol. 4 No. 12.

    ERIC Educational Resources Information Center

    Kral, Paul A.; And Others

    Investigates the effect of delay of reinforcement upon human discrimination learning with particular emphasis on the form of the gradient within the first few seconds of delay. In previous studies subjects are usually required to make an instrumental response to a stimulus, this is followed by the delay interval, and finally, the reinforcement…

  10. The Effect of Delayed Auditory Feedback on Activity in the Temporal Lobe while Speaking: A Positron Emission Tomography Study

    ERIC Educational Resources Information Center

    Takaso, Hideki; Eisner, Frank; Wise, Richard J. S.; Scott, Sophie K.

    2010-01-01

    Purpose: Delayed auditory feedback is a technique that can improve fluency in stutterers, while disrupting fluency in many nonstuttering individuals. The aim of this study was to determine the neural basis for the detection of and compensation for such a delay, and the effects of increases in the delay duration. Method: Positron emission…

  11. The Effect of Delayed Auditory Feedback on Activity in the Temporal Lobe while Speaking: A Positron Emission Tomography Study

    ERIC Educational Resources Information Center

    Takaso, Hideki; Eisner, Frank; Wise, Richard J. S.; Scott, Sophie K.

    2010-01-01

    Purpose: Delayed auditory feedback is a technique that can improve fluency in stutterers, while disrupting fluency in many nonstuttering individuals. The aim of this study was to determine the neural basis for the detection of and compensation for such a delay, and the effects of increases in the delay duration. Method: Positron emission…

  12. Genetic Diversity in Introduced Populations with an Allee Effect

    PubMed Central

    Wittmann, Meike J.; Gabriel, Wilfried; Metzler, Dirk

    2014-01-01

    A phenomenon that strongly influences the demography of small introduced populations and thereby potentially their genetic diversity is the demographic Allee effect, a reduction in population growth rates at small population sizes. We take a stochastic modeling approach to investigate levels of genetic diversity in populations that successfully overcame either a strong Allee effect, in which populations smaller than a certain critical size are expected to decline, or a weak Allee effect, in which the population growth rate is reduced at small sizes but not negative. Our results indicate that compared to successful populations without an Allee effect, successful populations with a strong Allee effect tend to (1) derive from larger founder population sizes and thus have a higher initial amount of genetic variation, (2) spend fewer generations at small population sizes where genetic drift is particularly strong, and (3) spend more time around the critical population size and thus experience more genetic drift there. In the case of multiple introduction events, there is an additional increase in diversity because Allee-effect populations tend to derive from a larger number of introduction events than other populations. Altogether, a strong Allee effect can either increase or decrease genetic diversity, depending on the average founder population size. By contrast, a weak Allee effect tends to decrease genetic diversity across the entire range of founder population sizes. Finally, we show that it is possible in principle to infer critical population sizes from genetic data, although this would require information from many independently introduced populations. PMID:25009147

  13. The Effects of Discipline Responses in Delaying Toddler Misbehavior Recurrences.

    ERIC Educational Resources Information Center

    Larzelere, Robert E.; Schneider, William N.; Larson, David B.; Pike, Patricia L.

    1996-01-01

    Compares the effectiveness of maternal punishment (time out, spanking), reasoning, and a combination of the two. Results based on mothers' (N=40) structured diaries of toddler fighting and disobedience indicate that mild punishment, combined with reasoning, is an effective discipline response to toddler misbehavior in terms of recurrence of…

  14. A White-headed langurs impulsive state feedback control model with sparse effect and continuous delay

    NASA Astrophysics Data System (ADS)

    Chen, Shidong; Xu, Weijian; Chen, Lansun; Huang, Zhonghao

    2017-09-01

    In this paper, a white-headed langurs impulsive state feedback control model with sparse effect and continuous delay is investigated. We get the sufficient condition under which the system has a unique order-1 periodic solution through the method of successor function, and prove the stability of the order-1 periodic solution by the limit method of the successor point sequences. Furthermore, we perform numerical analysis on the theoretical results. Our results show that artificial breeding and releasing langurs in captive to the wild can effectively protect wild white-headed langurs with sparse effect and continuous delay.

  15. Effect of the Colorado River Diversion on Matagorda Bay Epifauna

    NASA Astrophysics Data System (ADS)

    Wilber, D. H.; Bass, R.

    1998-09-01

    The effect on epifauna of the Colorado River diversion, which restored river flow to Matagorda Bay, Texas, U.S.A. was assessed using three independent data sets and analytical approaches. A monitoring study conducted by the Galveston District, U.S. Corps of Engineers, revealed lower croaker and brown shrimp abundances for 3 years following the diversion compared to their abundances during 3 pre-diversion years. No changes in the abundances of white shrimp, blue crabs and spot were evident in this monitoring study. The relative distributions of these common epifaunal organisms within the eastern arm of the bay, where the redirected river-mouth empties, did not change following the diversion. Analyses of data (1982-1995) from a long-term trawl-survey programme conducted by the Texas Parks and Wildlife Department (TPWD) indicated that the catches of common epibenthic organisms in the eastern arm of the bay following the diversion were also within the range of historic variation. Species richness decreased significantly at the eastern stations where salinities were lower following the diversion. Commercial fishery landings of most species in the post-diversion period were within the range of historic variation. Oyster landings, however, were consistently low for the 4 years for which post-diversion data were available, probably because previously harvestable reefs were lost to sedimentation and burial close to the redirected river mouth. Prior to the diversion (1970-1991), oyster landings were negatively associated with the same year's maximum annual river flows and the duration of low flows (<14 m 3 s -1) 2 years previous ( r2=0·63, P<0·001). The regression results indicate that post-diversion increases in freshwater inflows during low flow periods will likely benefit oyster harvests 2 years later Increases to oyster yields may take several more years to be realized and will be contingent upon the success of harvests from the newly created oyster reefs along the

  16. Working-Memory Training: Effects on Delay Discounting in Male Long Evans Rats

    PubMed Central

    Renda, C. Renee; Stein, Jeffrey S.; Madden, Gregory J.

    2014-01-01

    Delay discounting describes the devaluation of a reward as the delay to the receipt of the reward increases. Because steep delay discounting is robustly correlated with a number of behavioral problems (e.g., substance dependence, gambling) and some evidence suggests steep discounting precedes and predicts drug-taking in humans and rats, this study sought to experimentally reduce rats' delay discounting. Human stimulant-dependent participants given working-memory training reportedly decreased their rates of discounting relative to a sham-training group (Bickel, Yi, Landes, Hill, & Baxter, 2011). To evaluate the cross-species generality of this effect, 38 male Long-Evans rats, matched on pretraining delay-discounting rates, were randomly assigned to receive 140 sessions of working-memory training or sham training (which required no memory of the sample stimulus). Large between-group differences in working memory were observed after training; however, posttraining delay-discounting rates were undifferentiated across groups. Potential explanations for these findings are discussed. PMID:25418508

  17. Tolerable delay for speech production and perception: effects of hearing ability and experience with hearing aids.

    PubMed

    Goehring, Tobias; Chapman, Josie L; Bleeck, Stefan; Monaghan, Jessica J M

    2017-08-24

    Processing delay is one of the important factors that limit the development of novel algorithms for hearing devices. In this study, both normal-hearing listeners and listeners with hearing loss were tested for their tolerance of processing delay up to 50 ms using a real-time setup for own-voice and external-voice conditions based on linear processing to avoid confounding effects of time-dependent gain. Participants rated their perceived subjective annoyance for each condition on a 7-point Likert scale. Twenty normal-hearing participants and twenty participants with a range of mild to moderate hearing losses. Delay tolerance was significantly greater for the participants with hearing loss in two out of three voice conditions. The average slopes of annoyance ratings were negatively correlated with the degree of hearing loss across participants. A small trend of higher tolerance of delay by experienced users of hearing aids in comparison to new users was not significant. The increased tolerance of processing delay for speech production and perception with hearing loss and reduced sensitivity to changes in delay with stronger hearing loss may be beneficial for novel algorithms for hearing devices but the setup used in this study differed from commercial hearing aids.

  18. Effectiveness of Delayed Cord Clamping in Reducing Postdelivery Complications in Preterm Infants: A Systematic Review.

    PubMed

    Chapman, Jessica; Marfurt, Stephanie; Reid, Julie

    This systematic review evaluates the effectiveness of delayed cord clamping in preterm infants on reducing postdelivery complications of anemia, hemodynamic instability, and the development of intraventricular hemorrhages. Interventions included varying durations of delayed cord clamping with and without cord milking as compared with immediate cord clamping, shorter delays in cord clamping, and delayed cord clamping without cord milking. A comprehensive search of randomized controlled trials, observational, cohort, and before-after studies was conducted between 1946 and 2015 in the electronic databases of Ovid MEDLINE, Embase, and Google Scholar. Studies were critically appraised using the Critical Appraisal Skills Program guidelines. Twenty-seven studies were included in the review from 1997 to 2015 from varying countries. Outcome measures included hematocrit/hemoglobin levels, measured or calculated blood volumes levels, number and volume of blood transfusions, presence of hypotension and need for treatment, and development of intraventricular hemorrhage. Delayed cord clamping can lead to improved outcomes measures in preterm infants. This review supports the current recommendation to perform delayed cord clamping during preterm deliveries.

  19. Effects of delayed polymerization time and bracket manipulation on orthodontic resin modified glass ionomer adhesive

    NASA Astrophysics Data System (ADS)

    Gilbert, Danielle Wiggins

    This study examined the effect of varying delayed polymerization times in combination with bracket manipulation on shear bond strength (SBS), degree of conversion (DC), and adhesive remnant index (ARI) score when using a resin modified glass ionomer (RMGI) adhesive. Specimens were divided into three groups of clinically relevant delay times (0.5, 2, and 4-min) to simulate the delay that frequently occurs between bracket placement and manipulation and subsequent light curing. Based on an analysis of variance (alpha=.05), the SBS was not significantly different between the three groups. While one of the goals of this study was to be the first study to quantify DC of RMGI using Raman microspectroscopy, several challenges, including weak peak signal with and without fluorescence, were encountered and as a result, DC could not be determined. A significant difference (p<0.05) in ARI score was detected between the 0.5-min and 4.0-min delay groups with more adhesive remaining on the bracket with increasing delay time. A Spearman correlation between SBS and ARI indicated no positive association between SBS and ARI measures across delay times. The results of this study suggest that clinically relevant delay times of 0.5, 2, and 4-min do not negatively impact the SBS of a RMGI adhesive. However, with increasing delay time, the results suggest that more adhesive might remain on the bracket during debonding. With more adhesive remaining on the bracket, this could be beneficial in that less adhesive needs to be removed from enamel by grinding at the time of bracket removal when orthodontic treatment is completed.

  20. Health system delay and its effect on clinical stage of breast cancer: Multicenter study.

    PubMed

    Unger-Saldaña, Karla; Miranda, Alfonso; Zarco-Espinosa, Gelasio; Mainero-Ratchelous, Fernando; Bargalló-Rocha, Enrique; Miguel Lázaro-León, Jesús

    2015-07-01

    The objective of this study was to determine the correlation between health system delay and clinical disease stage in patients with breast cancer. This was a cross-sectional study of 886 patients who were referred to 4 of the largest public cancer hospitals in Mexico City for the evaluation of a probable breast cancer. Data on time intervals, sociodemographic factors, and clinical stage at diagnosis were retrieved. A logistic regression model was used to estimate the average marginal effects of delay on the probability of being diagnosed with advanced breast cancer (stages III and IV). The median time between problem identification and the beginning of treatment was 7 months. The subinterval with the largest delay was that between the first medical consultation and diagnosis (median, 4 months). Only 15% of the patients who had cancer were diagnosed with stage 0 and I disease, and 48% were diagnosed with stage III and IV disease. Multivariate analyses confirmed independent correlations for the means of problem identification, patient delay, health system delay, and age with a higher probability that patients would begin cancer treatment in an advanced stage. In the sample studied, the majority of patients with breast cancer began treatment after a delay. Both patient delays and provider delays were associated with advanced disease. Research aimed at identifying specific access barriers to medical services is much needed to guide the design of tailored health policies that go beyond the promotion of breast care awareness and screening participation to include improvements in health services that facilitate access to timely diagnosis and treatment. © 2015 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society.

  1. Immediate and Delayed Effects of Invented Writing Intervention in Preschool

    ERIC Educational Resources Information Center

    Hofslundsengen, Hilde; Hagtvet, Bente Eriksen; Gustafsson, Jan-Eric

    2016-01-01

    This study examined the effects of a 10 week invented writing program with five-year-old preschoolers (mean age 5.7 years) on their immediate post intervention literacy skills and also the facilitative effects of the intervention on the subsequent learning to read during the first 6 months of schooling. The study included 105 children (54 girls)…

  2. Effects of large herbivores on grassland arthropod diversity.

    PubMed

    van Klink, R; van der Plas, F; van Noordwijk, C G E Toos; WallisDeVries, M F; Olff, H

    2015-05-01

    Both arthropods and large grazing herbivores are important components and drivers of biodiversity in grassland ecosystems, but a synthesis of how arthropod diversity is affected by large herbivores has been largely missing. To fill this gap, we conducted a literature search, which yielded 141 studies on this topic of which 24 simultaneously investigated plant and arthropod diversity. Using the data from these 24 studies, we compared the responses of plant and arthropod diversity to an increase in grazing intensity. This quantitative assessment showed no overall significant effect of increasing grazing intensity on plant diversity, while arthropod diversity was generally negatively affected. To understand these negative effects, we explored the mechanisms by which large herbivores affect arthropod communities: direct effects, changes in vegetation structure, changes in plant community composition, changes in soil conditions, and cascading effects within the arthropod interaction web. We identify three main factors determining the effects of large herbivores on arthropod diversity: (i) unintentional predation and increased disturbance, (ii) decreases in total resource abundance for arthropods (biomass) and (iii) changes in plant diversity, vegetation structure and abiotic conditions. In general, heterogeneity in vegetation structure and abiotic conditions increases at intermediate grazing intensity, but declines at both low and high grazing intensity. We conclude that large herbivores can only increase arthropod diversity if they cause an increase in (a)biotic heterogeneity, and then only if this increase is large enough to compensate for the loss of total resource abundance and the increased mortality rate. This is expected to occur only at low herbivore densities or with spatio-temporal variation in herbivore densities. As we demonstrate that arthropod diversity is often more negatively affected by grazing than plant diversity, we strongly recommend considering the

  3. Effects of large herbivores on grassland arthropod diversity

    PubMed Central

    van Klink, R; van der Plas, F; van Noordwijk, C G E (Toos); WallisDeVries, M F; Olff, H

    2015-01-01

    Both arthropods and large grazing herbivores are important components and drivers of biodiversity in grassland ecosystems, but a synthesis of how arthropod diversity is affected by large herbivores has been largely missing. To fill this gap, we conducted a literature search, which yielded 141 studies on this topic of which 24 simultaneously investigated plant and arthropod diversity. Using the data from these 24 studies, we compared the responses of plant and arthropod diversity to an increase in grazing intensity. This quantitative assessment showed no overall significant effect of increasing grazing intensity on plant diversity, while arthropod diversity was generally negatively affected. To understand these negative effects, we explored the mechanisms by which large herbivores affect arthropod communities: direct effects, changes in vegetation structure, changes in plant community composition, changes in soil conditions, and cascading effects within the arthropod interaction web. We identify three main factors determining the effects of large herbivores on arthropod diversity: (i) unintentional predation and increased disturbance, (ii) decreases in total resource abundance for arthropods (biomass) and (iii) changes in plant diversity, vegetation structure and abiotic conditions. In general, heterogeneity in vegetation structure and abiotic conditions increases at intermediate grazing intensity, but declines at both low and high grazing intensity. We conclude that large herbivores can only increase arthropod diversity if they cause an increase in (a)biotic heterogeneity, and then only if this increase is large enough to compensate for the loss of total resource abundance and the increased mortality rate. This is expected to occur only at low herbivore densities or with spatio-temporal variation in herbivore densities. As we demonstrate that arthropod diversity is often more negatively affected by grazing than plant diversity, we strongly recommend considering the

  4. Effective delayed neutron fraction and prompt neutron lifetime of Tehran research reactor mixed-core

    PubMed Central

    Lashkari, A.; Khalafi, H.; Kazeminejad, H.

    2013-01-01

    In this work, kinetic parameters of Tehran research reactor (TRR) mixed cores have been calculated. The mixed core configurations are made by replacement of the low enriched uranium control fuel elements with highly enriched uranium control fuel elements in the reference core. The MTR_PC package, a nuclear reactor analysis tool, is used to perform the analysis. Simulations were carried out to compute effective delayed neutron fraction and prompt neutron lifetime. Calculation of kinetic parameters is necessary for reactivity and power excursion transient analysis. The results of this research show that effective delayed neutron fraction decreases and prompt neutron lifetime increases with the fuels burn-up. Also, by increasing the number of highly enriched uranium control fuel elements in the reference core, the prompt neutron lifetime increases, but effective delayed neutron fraction does not show any considerable change. PMID:24976672

  5. Effective delayed neutron fraction and prompt neutron lifetime of Tehran research reactor mixed-core.

    PubMed

    Lashkari, A; Khalafi, H; Kazeminejad, H

    2013-05-01

    In this work, kinetic parameters of Tehran research reactor (TRR) mixed cores have been calculated. The mixed core configurations are made by replacement of the low enriched uranium control fuel elements with highly enriched uranium control fuel elements in the reference core. The MTR_PC package, a nuclear reactor analysis tool, is used to perform the analysis. Simulations were carried out to compute effective delayed neutron fraction and prompt neutron lifetime. Calculation of kinetic parameters is necessary for reactivity and power excursion transient analysis. The results of this research show that effective delayed neutron fraction decreases and prompt neutron lifetime increases with the fuels burn-up. Also, by increasing the number of highly enriched uranium control fuel elements in the reference core, the prompt neutron lifetime increases, but effective delayed neutron fraction does not show any considerable change.

  6. Assessing the Effectiveness of Parent-Child Interaction Therapy with Language Delayed Children: A Clinical Investigation

    ERIC Educational Resources Information Center

    Falkus, Gila; Tilley, Ciara; Thomas, Catherine; Hockey, Hannah; Kennedy, Anna; Arnold, Tina; Thorburn, Blair; Jones, Katie; Patel, Bhavika; Pimenta, Claire; Shah, Rena; Tweedie, Fiona; O'Brien, Felicity; Leahy, Ruth; Pring, Tim

    2016-01-01

    Parent-child interaction therapy (PCIT) is widely used by speech and language therapists to improve the interactions between children with delayed language development and their parents/carers. Despite favourable reports of the therapy from clinicians, little evidence of its effectiveness is available. We investigated the effects of PCIT as…

  7. The Effects of Social Skills Groups for Young Children with Social Delays

    ERIC Educational Resources Information Center

    Koyama, Takanori

    2011-01-01

    This study was conducted as a program evaluation of an existing social skills program. A review of literature identified a limited number of empirical studies on group-based social skills training for young children with social delays. The purpose of this study was to examine the effects of social skills groups as well as the effects of homework…

  8. Assessing the Effectiveness of Parent-Child Interaction Therapy with Language Delayed Children: A Clinical Investigation

    ERIC Educational Resources Information Center

    Falkus, Gila; Tilley, Ciara; Thomas, Catherine; Hockey, Hannah; Kennedy, Anna; Arnold, Tina; Thorburn, Blair; Jones, Katie; Patel, Bhavika; Pimenta, Claire; Shah, Rena; Tweedie, Fiona; O'Brien, Felicity; Leahy, Ruth; Pring, Tim

    2016-01-01

    Parent-child interaction therapy (PCIT) is widely used by speech and language therapists to improve the interactions between children with delayed language development and their parents/carers. Despite favourable reports of the therapy from clinicians, little evidence of its effectiveness is available. We investigated the effects of PCIT as…

  9. Effects of partial time delays on phase synchronization in Watts-Strogatz small-world neuronal networks

    NASA Astrophysics Data System (ADS)

    Sun, Xiaojuan; Perc, Matjaž; Kurths, Jürgen

    2017-05-01

    In this paper, we study effects of partial time delays on phase synchronization in Watts-Strogatz small-world neuronal networks. Our focus is on the impact of two parameters, namely the time delay τ and the probability of partial time delay pdelay, whereby the latter determines the probability with which a connection between two neurons is delayed. Our research reveals that partial time delays significantly affect phase synchronization in this system. In particular, partial time delays can either enhance or decrease phase synchronization and induce synchronization transitions with changes in the mean firing rate of neurons, as well as induce switching between synchronized neurons with period-1 firing to synchronized neurons with period-2 firing. Moreover, in comparison to a neuronal network where all connections are delayed, we show that small partial time delay probabilities have especially different influences on phase synchronization of neuronal networks.

  10. Automated problem scheduling and reduction of synchronization delay effects

    NASA Technical Reports Server (NTRS)

    Saltz, Joel H.

    1987-01-01

    It is anticipated that in order to make effective use of many future high performance architectures, programs will have to exhibit at least a medium grained parallelism. A framework is presented for partitioning very sparse triangular systems of linear equations that is designed to produce favorable preformance results in a wide variety of parallel architectures. Efficient methods for solving these systems are of interest because: (1) they provide a useful model problem for use in exploring heuristics for the aggregation, mapping and scheduling of relatively fine grained computations whose data dependencies are specified by directed acrylic graphs, and (2) because such efficient methods can find direct application in the development of parallel algorithms for scientific computation. Simple expressions are derived that describe how to schedule computational work with varying degrees of granularity. The Encore Multimax was used as a hardware simulator to investigate the performance effects of using the partitioning techniques presented in shared memory architectures with varying relative synchronization costs.

  11. Glucocorticoids Protect Against the Delayed Behavioral and Cellular Effects of Acute Stress on the Amygdala

    PubMed Central

    Rao, Rajnish P.; Anilkumar, Shobha; McEwen, Bruce; Chattarji, Sumantra

    2013-01-01

    Background A single episode of acute immobilization stress has previously been shown to trigger a delayed onset of anxiety-like behavior and spinogenesis in the basolateral amygdala (BLA) of rats. Spurred on by a seemingly paradoxical observation in which even a modest increase in corticosterone (CORT), caused by a single vehicle injection before stress, could dampen the delayed effects of stress, we hypothesized a protective role for glucocorticoids against stress. Methods We tested this hypothesis by analyzing how manipulations in CORT levels modulate delayed increase in anxiety-like behavior of rats on the elevated plus-maze 10 days after acute stress. We also investigated the cellular correlates of different levels of anxiety under different CORT conditions by quantifying spine density on Golgi-stained BLA principal neurons. Results CORT in drinking water for 12 hours preceding acute stress prevented delayed increase in anxiety rather than exacerbating it. Conversely, vehicle injection failed to prevent the anxiogenic effect of stress in bilaterally adrenalectomized rats. However, when CORT was restored in adrenalectomized rats by injection, the delayed anxiogenic effect of stress was once again blocked. Finally, high and low anxiety states were accompanied by high and low levels of BLA spine density. Conclusions Our findings suggest that the presence of elevated levels of CORT at the time of acute stress confers protection against the delayed enhancing effect of stress on BLA synaptic connectivity and anxiety-like behavior. These observations are consistent with clinical reports on the protective effects of glucocorticoids against the development of posttraumatic symptoms triggered by traumatic stress. PMID:22572034

  12. Population density of North American elk: effects on plant diversity.

    PubMed

    Stewart, Kelley M; Bowyer, R Terry; Kie, John G; Dick, Brian L; Ruess, Roger W

    2009-08-01

    Large, herbivorous mammals have profound effects on ecosystem structure and function and often act as keystone species in ecosystems they inhabit. Density-dependent processes associated with population structure of large mammals may interact with ecosystem functioning to increase or decrease biodiversity, depending on the relationship of herbivore populations relative to the carrying capacity (K) of the ecosystem. We tested for indirect effects of population density of large herbivores on plant species richness and diversity in a montane ecosystem, where increased net aboveground primary productivity (NAPP) in response to low levels of herbivory has been reported. We documented a positive, linear relationship between plant-species diversity and richness with NAPP. Structural equation modeling revealed significant indirect relationships between population density of herbivores, NAPP, and species diversity. We observed an indirect effect of density-dependent processes in large, herbivorous mammals and species diversity of plants through changes in NAPP in this montane ecosystem. Changes in species diversity of plants in response to herbivory may be more indirect in ecosystems with long histories of herbivory. Those subtle or indirect effects of herbivory may have strong effects on ecosystem functioning, but may be overlooked in plant communities that are relatively resilient to herbivory.

  13. Population diversity and the portfolio effect in an exploited species.

    PubMed

    Schindler, Daniel E; Hilborn, Ray; Chasco, Brandon; Boatright, Christopher P; Quinn, Thomas P; Rogers, Lauren A; Webster, Michael S

    2010-06-03

    One of the most pervasive themes in ecology is that biological diversity stabilizes ecosystem processes and the services they provide to society, a concept that has become a common argument for biodiversity conservation. Species-rich communities are thought to produce more temporally stable ecosystem services because of the complementary or independent dynamics among species that perform similar ecosystem functions. Such variance dampening within communities is referred to as a portfolio effect and is analogous to the effects of asset diversity on the stability of financial portfolios. In ecology, these arguments have focused on the effects of species diversity on ecosystem stability but have not considered the importance of biologically relevant diversity within individual species. Current rates of population extirpation are probably at least three orders of magnitude higher than species extinction rates, so there is a pressing need to clarify how population and life history diversity affect the performance of individual species in providing important ecosystem services. Here we use five decades of data from Oncorhynchus nerka (sockeye salmon) in Bristol Bay, Alaska, to provide the first quantification of portfolio effects that derive from population and life history diversity in an important and heavily exploited species. Variability in annual Bristol Bay salmon returns is 2.2 times lower than it would be if the system consisted of a single homogenous population rather than the several hundred discrete populations it currently consists of. Furthermore, if it were a single homogeneous population, such increased variability would lead to ten times more frequent fisheries closures. Portfolio effects are also evident in watershed food webs, where they stabilize and extend predator access to salmon resources. Our results demonstrate the critical importance of maintaining population diversity for stabilizing ecosystem services and securing the economies and livelihoods

  14. Eutrophication weakens stabilizing effects of diversity in natural grasslands.

    PubMed

    Hautier, Yann; Seabloom, Eric W; Borer, Elizabeth T; Adler, Peter B; Harpole, W Stanley; Hillebrand, Helmut; Lind, Eric M; MacDougall, Andrew S; Stevens, Carly J; Bakker, Jonathan D; Buckley, Yvonne M; Chu, Chengjin; Collins, Scott L; Daleo, Pedro; Damschen, Ellen I; Davies, Kendi F; Fay, Philip A; Firn, Jennifer; Gruner, Daniel S; Jin, Virginia L; Klein, Julia A; Knops, Johannes M H; La Pierre, Kimberly J; Li, Wei; McCulley, Rebecca L; Melbourne, Brett A; Moore, Joslin L; O'Halloran, Lydia R; Prober, Suzanne M; Risch, Anita C; Sankaran, Mahesh; Schuetz, Martin; Hector, Andy

    2014-04-24

    Studies of experimental grassland communities have demonstrated that plant diversity can stabilize productivity through species asynchrony, in which decreases in the biomass of some species are compensated for by increases in others. However, it remains unknown whether these findings are relevant to natural ecosystems, especially those for which species diversity is threatened by anthropogenic global change. Here we analyse diversity-stability relationships from 41 grasslands on five continents and examine how these relationships are affected by chronic fertilization, one of the strongest drivers of species loss globally. Unmanipulated communities with more species had greater species asynchrony, resulting in more stable biomass production, generalizing a result from biodiversity experiments to real-world grasslands. However, fertilization weakened the positive effect of diversity on stability. Contrary to expectations, this was not due to species loss after eutrophication but rather to an increase in the temporal variation of productivity in combination with a decrease in species asynchrony in diverse communities. Our results demonstrate separate and synergistic effects of diversity and eutrophication on stability, emphasizing the need to understand how drivers of global change interactively affect the reliable provisioning of ecosystem services in real-world systems.

  15. Delay time dependence of thermal effect of combined pulse laser machining

    NASA Astrophysics Data System (ADS)

    Yuan, Boshi; Jin, Guangyong; Ma, Yao; Zhang, Wei

    2016-10-01

    The research focused on the effect of delay time in combined pulse laser machining on the material temperature field. Aiming at the parameter optimization of pulse laser machining aluminum alloy, the combined pulse laser model based on heat conduction equation was introduced. And the finite element analysis software, COMSOL Multiphysics, was also utilized in the research. Without considering the phase transition process of aluminum alloy, the results of the numerical simulation was shown in this paper. By the simulation study of aluminum alloy's irradiation with combined pulse, the effect of the change in delay time of combined pulse on the temperature field of the aluminum alloy and simultaneously the quantized results under the specific laser spot conditions were obtained. Based on the results, several conclusions could be reached, the delay time could affect the rule of temperature changing with time. The reasonable delay time controlling would help improving the efficiency. In addition, when the condition of the laser pulse energy density is constant, the optimal delay time depends on pulse sequence.

  16. Effects of additional food in a delayed predator-prey model.

    PubMed

    Sahoo, Banshidhar; Poria, Swarup

    2015-03-01

    We examine the effects of supplying additional food to predator in a gestation delay induced predator-prey system with habitat complexity. Additional food works in favor of predator growth in our model. Presence of additional food reduces the predatory attack rate to prey in the model. Supplying additional food we can control predator population. Taking time delay as bifurcation parameter the stability of the coexisting equilibrium point is analyzed. Hopf bifurcation analysis is done with respect to time delay in presence of additional food. The direction of Hopf bifurcations and the stability of bifurcated periodic solutions are determined by applying the normal form theory and the center manifold theorem. The qualitative dynamical behavior of the model is simulated using experimental parameter values. It is observed that fluctuations of the population size can be controlled either by supplying additional food suitably or by increasing the degree of habitat complexity. It is pointed out that Hopf bifurcation occurs in the system when the delay crosses some critical value. This critical value of delay strongly depends on quality and quantity of supplied additional food. Therefore, the variation of predator population significantly effects the dynamics of the model. Model results are compared with experimental results and biological implications of the analytical findings are discussed in the conclusion section.

  17. The effects of physical activity on impulsive choice: Influence of sensitivity to reinforcement amount and delay.

    PubMed

    Strickland, Justin C; Feinstein, Max A; Lacy, Ryan T; Smith, Mark A

    2016-05-01

    Impulsive choice is a diagnostic feature and/or complicating factor for several psychological disorders and may be examined in the laboratory using delay-discounting procedures. Recent investigators have proposed using quantitative measures of analysis to examine the behavioral processes contributing to impulsive choice. The purpose of this study was to examine the effects of physical activity (i.e., wheel running) on impulsive choice in a single-response, discrete-trial procedure using two quantitative methods of analysis. To this end, rats were assigned to physical activity or sedentary groups and trained to respond in a delay-discounting procedure. In this procedure, one lever always produced one food pellet immediately, whereas a second lever produced three food pellets after a 0, 10, 20, 40, or 80-s delay. Estimates of sensitivity to reinforcement amount and sensitivity to reinforcement delay were determined using (1) a simple linear analysis and (2) an analysis of logarithmically transformed response ratios. Both analyses revealed that physical activity decreased sensitivity to reinforcement amount and sensitivity to reinforcement delay. These findings indicate that (1) physical activity has significant but functionally opposing effects on the behavioral processes that contribute to impulsive choice and (2) both quantitative methods of analysis are appropriate for use in single-response, discrete-trial procedures. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Delay-Induced Triple-Zero Bifurcation in a Delayed Leslie-Type Predator-Prey Model with Additive Allee Effect

    NASA Astrophysics Data System (ADS)

    Jiang, Jiao; Song, Yongli; Yu, Pei

    2016-06-01

    In this paper, a Leslie-type predator-prey model with ratio-dependent functional response and Allee effect on prey is considered. We first study the existence of the multiple positive equilibria and their stability. Then we investigate the effect of delay on the distribution of the roots of characteristic equation and obtain the conditions for the occurrence of simple-zero, double-zero and triple-zero singularities. The formulations for calculating the normal form of the triple-zero bifurcation of the delay differential equations are derived. We show that, under certain conditions on the parameters, the system exhibits homoclinic orbit, heteroclinic orbit and periodic orbit.

  19. Delayed hemorrhage effect of local anesthesia with epinephrine in the loop electrosurgical excisional procedure

    PubMed Central

    Lee, Yong Jae; Park, Yunjin; Lee, In Ok; Yoon, Jung Won; Lee, Jung Yoon; Kim, Sang Wun; Kim, Sunghoon; Kim, Young Tae

    2017-01-01

    Objective The aim of this study was to investigate factors preventing delayed hemorrhage after the loop electrosurgical excisional procedure (LEEP). Methods Medical records of patients who underwent LEEP at one university affiliated hospital from October 2013 to January 2015 were reviewed. Patients with or without delayed hemorrhage were classified. LEEP was performed either in an operating room under general anesthesia or in a procedure room with local anesthesia in the outpatient clinic. Delayed hemorrhage was defined as excisional site bleeding occurring between 1 and 30 days after the LEEP requiring intervention such as electro-cauterization, gauze packing, or application of another hemostatic agent. Results During the study period, 369 patients underwent LEEP. Twenty-three (6.2%) patients with delayed hemorrhage returned to our hospital either to the outpatient clinic or to the emergency unit. A third of the population (103, 27.9%) underwent LEEP in the operating room under general anesthesia without injection of local anesthesia. The remaining patients (266, 72.1%) underwent LEEP with local anesthesia (lidocaine HCl 2% with epinephrine 1:100,000) in the office procedure room. Patients given local anesthesia including epinephrine had significantly lower delayed hemorrhage compared to patients with general anesthesia without injection of local anesthesia (P=0.001). Hemostats, such as fibrin glue or patch, were used for the majority of patients (346, 93.8%) during the procedure. However, using hemostats was not statistically associated with delayed hemorrhage (P=0.163). Conclusion Local anesthesia with the powerful vasoconstrictor epinephrine is effective not only to control perioperative bleeding, but also to prevent delayed hemorrhage after LEEP. PMID:28217677

  20. Effects of Concurrent and Delayed Visual Feedback on Motor Memory Consolidation.

    PubMed

    Wang, Dangxiao; Li, Teng; Yang, Gaofeng; Zhang, Yuru

    2017-02-22

    In many domains, it's important to understand the ways in which humans learn and develop new motor skills effectively and efficiently. For example, in dental operations, the ability to apply a weak force with a required tolerance is a fundamental skill to ensure diagnostic and treatment outcome, but acquiring such a skill is a challenge for novices. In this paper, we focus on motor memory for producing normally applied force by a hand-held probe and we compare the effects of two feedback methods on motor memory consolidation. Fourteen participants were randomly assigned to two groups: a Concurrent Group and a Delayed Group. Participants in the Concurrent Group were trained to apply a target force with concurrent visual feedback, while those in the Delayed Group were trained with delayed visual feedback. The task included two phases: a Training/Testing Phase, and a Retention Phase. The results indicated that participants in the Delayed Group obtained more effective learning outcomes and better retention effects. These findings provide a new perspective to explore the relationship between feedback methods and the cognitive process of motor skill learning, and open a new way to train motor skill using more effective methods than the traditional concurrent feedback approaches.

  1. Process-dependent risk of delayed health effects for welders.

    PubMed Central

    Stern, R M

    1981-01-01

    In most industrialized countries large numbers of workers are exposed to welding fumes. Although the general pattern of welders' health may not significantly differ from that of workers in other dusty industrial occupations which demonstrate elevated incidence of respiratory tract diseases with long latency periods, the extremely wide range of substances at potentially high concentrations produced by various welding technologies may give rise to undetected process-specific high-risk working conditions: ("hot spots"). The origin, prevalence and range of magnitude of such hot spots, especially for cancer of the respiratory tract, is discussed, with emphasis placed on the assessment of risk resulting from exposure to Cr(VI) and Ni accompanying the use of various technologies for the welding of stainless and high alloy steels. The wide variation of health effects found within the industry, however, indicates the need for a standard protocol for future epidemiological studies, as well as for the development of suitable methodologies for experimental risk assessment. PMID:7333241

  2. Delayed effect of craniotomy on experimental seizures in rats.

    PubMed

    Forcelli, Patrick A; Kalikhman, David; Gale, Karen

    2013-01-01

    Neurosurgical therapeutic interventions include components that are presumed to be therapeutically inert, such as craniotomy and electrode implantation. Because these procedures may themselves exert neuroactive actions, with anecdotal evidence suggesting that craniotomy and electrode placement may have a particularly significant impact on epileptic seizures, the importance of their inclusion in sham control groups has become more compelling. Here we set out to test the hypothesis that craniotomy alone is sufficient to alter experimental seizures in rats. We tested adult male rats for seizures evoked by pentylenetetrazole (70 mg/kg) between 3 and 20 days following placement of bilateral craniotomies (either 2.5 or 3.5 mm in diameter) in the parietal bone of the skull, without penetrating the dura. Control (sham-operated) animals underwent anesthesia and surgery without craniotomy. We found that craniotomy significantly decreased the severity of experimental seizures on postoperative days 3, 6, and 10; this effect was dependent on the size of craniotomy. Animals with craniotomies returned to control seizure severity by 20 days post-craniotomy. These data support the hypothesis that damage to the skull is sufficient to cause a significant alteration in seizure susceptibility over an extended postoperative period, and indicate that this damage should not be considered neurologically inert.

  3. Effect of Landscape Structure on Species Diversity

    PubMed Central

    Campos, Paulo R. A.; Rosas, Alexandre; de Oliveira, Viviane M.; Gomes, Marcelo A. F.

    2013-01-01

    The effects of habitat fragmentation and their implications for biodiversity is a central issue in conservation biology which still lacks an overall comprehension. There is not yet a clear consensus on how to quantify fragmentation even though it is quite common to couple the effects of habitat loss with habitat fragmentation on biodiversity. Here we address the spatial patterns of species distribution in fragmented landscapes, assuming a neutral community model. To build up the fragmented landscapes, we employ the fractional Brownian motion approach, which in turn permits us to tune the amount of habitat loss and degree of clumping of the landscape independently. The coupling between the neutral community model, here simulated by means of the coalescent method, and fractal neutral landscape models enables us to address how the species–area relationship changes as the spatial patterns of a landscape is varied. The species–area relationship is one of the most fundamental laws in ecology, considered as a central tool in conservation biology, and is used to predict species loss following habitat disturbances. Our simulation results indicate that the level of clumping has a major role in shaping the species–area relationship. For instance, more compact landscapes are more sensitive to the effects of habitat loss and speciation rate. Besides, the level of clumping determines the existence and extension of the power-law regime which is expected to hold at intermediate scales. The distributions of species abundance are strongly influenced by the degree of fragmentation. We also show that the first and second commonest species have approximately self-similar spatial distributions across scales, with the fractal dimensions of the support of the first and second commonest species being very robust to changes in the spatial patterns of the landscape. PMID:23840490

  4. Effect of the heterogeneous neuron and information transmission delay on stochastic resonance of neuronal networks

    NASA Astrophysics Data System (ADS)

    Wang, Qingyun; Zhang, Honghui; Chen, Guanrong

    2012-12-01

    We study the effect of heterogeneous neuron and information transmission delay on stochastic resonance of scale-free neuronal networks. For this purpose, we introduce the heterogeneity to the specified neuron with the highest degree. It is shown that in the absence of delay, an intermediate noise level can optimally assist spike firings of collective neurons so as to achieve stochastic resonance on scale-free neuronal networks for small and intermediate αh, which plays a heterogeneous role. Maxima of stochastic resonance measure are enhanced as αh increases, which implies that the heterogeneity can improve stochastic resonance. However, as αh is beyond a certain large value, no obvious stochastic resonance can be observed. If the information transmission delay is introduced to neuronal networks, stochastic resonance is dramatically affected. In particular, the tuned information transmission delay can induce multiple stochastic resonance, which can be manifested as well-expressed maximum in the measure for stochastic resonance, appearing every multiple of one half of the subthreshold stimulus period. Furthermore, we can observe that stochastic resonance at odd multiple of one half of the subthreshold stimulus period is subharmonic, as opposed to the case of even multiple of one half of the subthreshold stimulus period. More interestingly, multiple stochastic resonance can also be improved by the suitable heterogeneous neuron. Presented results can provide good insights into the understanding of the heterogeneous neuron and information transmission delay on realistic neuronal networks.

  5. Effects of a 3-Hour Sleep Delay on Sleep Homeostasis in Alcohol Dependent Adults

    PubMed Central

    Armitage, Roseanne; Hoffmann, Robert; Conroy, Deirdre A.; Arnedt, J. Todd; Brower, Kirk J.

    2012-01-01

    Objectives: This study evaluated slow wave activity homeostatic response to a mild sleep challenge in alcohol-dependent adults compared to healthy controls. Design: Participants maintained a 23:00-06:00 schedule for 5 days verified by actigraphy and diary, followed by 3 nights in the lab: adaptation, baseline, and a sleep delay night with an 02:00-09:00 schedule. Setting: Sleep ' Chronophysiology laboratory. Participants: 48 alcohol-dependent adults (39 men, 9 women) who were abstinent for at least 3 weeks and 16 healthy control adults (13 men, 3 women), 21-55 years of age participated in study. Interventions: N/A. Measurements and Results: Slow wave EEG activity (SWA) in consecutive NREM periods was compared between baseline and sleep delay nights and between AD and HC groups, using age and sex as statistical covariates. The AD group showed a blunted SWA response to sleep delay with significantly lower SWA power than the HC group. Exponential regression analyses confirmed lower asymptotic SWA with a slower decay rate over NREM sleep time in the AD group. Results were similar for raw SWA and %SWA on the delay night expressed relative to baseline SWA. Conclusions: Alcohol dependence is associated with impaired SWA regulation and a blunted response to a mild homeostatic sleep challenge. Citation: Armitage R; Hoffmann R; Conroy DA; Arnedt JT; Brower KJ. Effects of a 3-hour sleep delay on sleep homeostasis in alcohol dependent adults. SLEEP 2012;35(2):273-278. PMID:22294818

  6. Effects of stomatal delays on the economics of leaf gas exchange under intermittent light regimes.

    PubMed

    Vico, Giulia; Manzoni, Stefano; Palmroth, Sari; Katul, Gabriel

    2011-11-01

    • Understory plants are subjected to highly intermittent light availability and their leaf gas exchanges are mediated by delayed responses of stomata and leaf biochemistry to light fluctuations. In this article, the patterns in stomatal delays across biomes and plant functional types were studied and their effects on leaf carbon gains and water losses were quantified. • A database of more than 60 published datasets on stomatal responses to light fluctuations was assembled. To interpret these experimental observations, a leaf gas exchange model was developed and coupled to a novel formulation of stomatal movement energetics. The model was used to test whether stomatal delays optimize light capture for photosynthesis, whilst limiting transpiration and carbon costs for stomatal movement. • The data analysis showed that stomatal opening and closing delays occurred over a limited range of values and were strongly correlated. Plant functional type and climate were the most important drivers of stomatal delays, with faster responses in graminoids and species from dry climates. • Although perfectly tracking stomata would maximize photosynthesis and minimize transpiration at the expense of large opening costs, the observed combinations of opening and closure times appeared to be consistent with a near-optimal balance of carbon gain, water loss and movement costs. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.

  7. Effect of the heterogeneous neuron and information transmission delay on stochastic resonance of neuronal networks.

    PubMed

    Wang, Qingyun; Zhang, Honghui; Chen, Guanrong

    2012-12-01

    We study the effect of heterogeneous neuron and information transmission delay on stochastic resonance of scale-free neuronal networks. For this purpose, we introduce the heterogeneity to the specified neuron with the highest degree. It is shown that in the absence of delay, an intermediate noise level can optimally assist spike firings of collective neurons so as to achieve stochastic resonance on scale-free neuronal networks for small and intermediate α(h), which plays a heterogeneous role. Maxima of stochastic resonance measure are enhanced as α(h) increases, which implies that the heterogeneity can improve stochastic resonance. However, as α(h) is beyond a certain large value, no obvious stochastic resonance can be observed. If the information transmission delay is introduced to neuronal networks, stochastic resonance is dramatically affected. In particular, the tuned information transmission delay can induce multiple stochastic resonance, which can be manifested as well-expressed maximum in the measure for stochastic resonance, appearing every multiple of one half of the subthreshold stimulus period. Furthermore, we can observe that stochastic resonance at odd multiple of one half of the subthreshold stimulus period is subharmonic, as opposed to the case of even multiple of one half of the subthreshold stimulus period. More interestingly, multiple stochastic resonance can also be improved by the suitable heterogeneous neuron. Presented results can provide good insights into the understanding of the heterogeneous neuron and information transmission delay on realistic neuronal networks.

  8. A Time-Delayed Mathematical Model for Tumor Growth with the Effect of a Periodic Therapy.

    PubMed

    Xu, Shihe; Wei, Xiangqing; Zhang, Fangwei

    2016-01-01

    A time-delayed mathematical model for tumor growth with the effect of periodic therapy is studied. The establishment of the model is based on the reaction-diffusion dynamics and mass conservation law and is considered with a time delay in cell proliferation process. Sufficient conditions for the global stability of tumor free equilibrium are given. We also prove that if external concentration of nutrients is large the tumor will not disappear and the conditions under which there exist periodic solutions to the model are also determined. Results are illustrated by computer simulations.

  9. Growth delay effect of combined interstitial hyperthermia and brachytherapy in a rat solid tumor model.

    PubMed

    Papadopoulos, D; Kimler, B F; Estes, N C; Durham, F J

    1989-01-01

    The rat mammary AC33 solid tumor model was used to investigate the efficacy of interstitial hyperthermia and/or brachytherapy. Subcutaneous flank tumors were heated with an interstitial microwave (915 MHz) antenna to a temperature of 43 +/- 0.5 degrees C for 45 min for two treatments, three days apart, and/or implanted with Ir-192 seeds for three days (-25 Gy tumor dose). Following treatments, tumors were measured 2 to 3 times per week. Hyperthermia alone produced a modest delay in tumor volume regrowth, while brachytherapy was substantially more effective. The combination produced a improvement in tumor regrowth delay compared to brachytherapy alone.

  10. Effect of Delay on Search Decisions in a Task-Oriented Reading Environment

    ERIC Educational Resources Information Center

    Mañá, Amelia; Vidal-Abarca, Eduardo; Salmerón, Ladislao

    2017-01-01

    The goal of this study was to determine the effect of setting a delay between reading a text and answering comprehension questions on "when"-to-search and "what"-to-search decisions in a task-oriented reading environment. Fifty-five eighth-grade students were randomly divided into two groups. One group read one text, answered…

  11. The Delay of Principle B Effect (DPBE) and Its Absence in Some Languages

    ERIC Educational Resources Information Center

    Di Sciullo, Anna Maria; Aguero-Bautista, Calixto

    2008-01-01

    The Delay of Principle B Effect (DPBE) has been discussed in various studies that show that children around age 5 seem to violate Principle B of Binding Theory (Chomsky, 1981, and related works), when the antecedent of the pronoun is a name, but not when the antecedent is a quantifier. The analysis we propose can explain the DPBE in languages of…

  12. Effects of D-amphetamine on response acquisition with immediate and delayed reinforcement.

    PubMed

    LeSage, M G; Byrne, T; Poling, A

    1996-11-01

    The present study examined in 8-hour sessions the effects of d-amphetamine (1.0, 5.6, and 10 mg/kg) on the acquisition of lever-press responding in rats that were exposed to procedures in which water delivery was delayed by 0, 8, or 16 seconds relative to the response that produced it. Both nonresetting- and resetting-delay conditions were studied. Although neither shaping nor autoshaping occurred, substantial levels of operative-lever responding developed under all conditions in which responses produced water. The lowest dose (1.0 mg/kg) of d-amphetamine either had no effect on or increased operative-lever pressing, whereas higher doses typically produced an initial reduction in lever pressing. Nonetheless, overall rates of operative-lever pressing at these doses were as high as, or higher than, those observed with vehicle. Thus, response acquisition was observed under all reinforcement procedures at all drug doses. In the absence of the drug, most responding occurred on the operative lever when reinforcement was immediate. Such differential responding also developed under both nonresetting- and resetting-delay procedures when the delay was 8 seconds, but not when it was 16 seconds. d-Amphetamine did not affect the development of differential responding under any procedure. Thus, consistent with d-amphetamine's effects under repeated acquisition procedures, the drug had no detrimental effect on learning until doses that produced general behavioral disruption were administered.

  13. The Effects of Delayed Reinforcement on Variability and Repetition of Response Sequences

    ERIC Educational Resources Information Center

    Odum, Amy L.; Ward, Ryan D.; Burke, K. Anne; Barnes, Christopher A.

    2006-01-01

    Four experiments examined the effects of delays to reinforcement on key peck sequences of pigeons maintained under multiple schedules of contingencies that produced variable or repetitive behavior. In Experiments 1, 2, and 4, in the repeat component only the sequence right-right-left-left earned food, and in the vary component four-response…

  14. Microarray as a First Genetic Test in Global Developmental Delay: A Cost-Effectiveness Analysis

    ERIC Educational Resources Information Center

    Trakadis, Yannis; Shevell, Michael

    2011-01-01

    Aim: Microarray technology has a significantly higher clinical yield than karyotyping in individuals with global developmental delay (GDD). Despite this, it has not yet been routinely implemented as a screening test owing to the perception that this approach is more expensive. We aimed to evaluate the effect that replacing karyotype with…

  15. The Effects of Behavioral History on Response Acquisition with Immediate and Delayed Reinforcement

    ERIC Educational Resources Information Center

    Snycerski, Susan; Laraway, Sean; Huitema, Bradley E.; Poling, Alan

    2004-01-01

    Effects of prior exposure to the experimental chamber with levers present or absent and variable-time (VT) 60-s water deliveries arranged during one, five, or no 1-hr sessions were examined in rats during a 6-hr response-acquisition session in which presses on one lever produced water delivery immediately or after a 15-s resetting delay, and…

  16. Effects of wrapping time delays on fermentation characteristics of baled alfalfa silages

    USDA-ARS?s Scientific Manuscript database

    Baled silage is an attractive forage conservation approach for small and mid-sized dairy or beef producers, partly because it limits the risks associated with baling dry hay during wet or unstable weather conditions. Our objectives were to test the effects of delayed wrapping on silage fermentation,...

  17. The Delay of Principle B Effect (DPBE) and Its Absence in Some Languages

    ERIC Educational Resources Information Center

    Di Sciullo, Anna Maria; Aguero-Bautista, Calixto

    2008-01-01

    The Delay of Principle B Effect (DPBE) has been discussed in various studies that show that children around age 5 seem to violate Principle B of Binding Theory (Chomsky, 1981, and related works), when the antecedent of the pronoun is a name, but not when the antecedent is a quantifier. The analysis we propose can explain the DPBE in languages of…

  18. Effect of delayed wrapping and wrapping source on digestibility and intake of alfalfa silage in sheep

    USDA-ARS?s Scientific Manuscript database

    Delays often occur between baling and wrapping during production of baled silage that increases exposure time of the forage to oxygen. This study was conducted to investigate the effect of two different wrapping sources and time intervals between baling and wrapping on intake and digestibility of al...

  19. Effects of delayed winter harvest on biomass yield and quality of napiergrass and energycane

    USDA-ARS?s Scientific Manuscript database

    Napiergrass (Cenchrus purpureus Schumach) and energycane (Saccharum hyb.) are high-yielding perennial grasses that are well-suited for biomass production in the southeast USA. The purpose of this study was to determine the effects of delayed winter harvest on biomass yield and quality of these two ...

  20. Relative Effectiveness of Continued, Lapsed, and Delayed Smoking Prevention Intervention in Senior High School Students.

    ERIC Educational Resources Information Center

    Eckhardt, Laura; And Others

    1997-01-01

    Reports findings from the final year of a tobacco use prevention project for junior and senior high school students. After three years of intervention with junior high students, researchers assessed the relative effectiveness of continued, lapsed, and delayed interventions in high school. In grade 11, continued intervention students had the lowest…

  1. Rabeprazole sodium delayed-release multiparticulates: Effect of enteric coating layers on product performance.

    PubMed

    Tirpude, Rakesh N; Puranik, Prashant K

    2011-07-01

    Rabeprazole sodium is one of the most effective proton pump inhibitors (PPIs) used in antiulcer therapy. Like most other PPIs, owing to its acid-labile nature, the drug is formulated as enteric-coated dosage form. Conventional means of producing delayed release multiparticulate dosage forms of PPIs require large quantities of enteric polymer coatings. In the present study, in order to better evaluate the effect of polymeric coating on product performance, the pellet core structure and composition was kept constant. Four different enteric-coating formulations and designs were evaluated. Enteric-coated drug multiparticulates prepared with single polymeric coatings (acrylic or cellulosic) were compared with two different polymeric layer coatings to evaluate the effectiveness of latter coatings in more effectively producing a better rabeprazole sodium delayed-release pellet product. The pH-dependent, enteric acrylic, and cellulosic polymers were used either alone, in combination, or applied one over the other to impart delayed-release properties to the core drug pellets. It was demonstrated that dual delayed-release coating with two different enteric polymers-an inner acrylic coating followed by an outer cellulosic coating-yields the best product that provides all the desired physicochemical and drug dissolution characteristics.

  2. Rabeprazole sodium delayed-release multiparticulates: Effect of enteric coating layers on product performance

    PubMed Central

    Tirpude, Rakesh N.; Puranik, Prashant K.

    2011-01-01

    Rabeprazole sodium is one of the most effective proton pump inhibitors (PPIs) used in antiulcer therapy. Like most other PPIs, owing to its acid-labile nature, the drug is formulated as enteric-coated dosage form. Conventional means of producing delayed release multiparticulate dosage forms of PPIs require large quantities of enteric polymer coatings. In the present study, in order to better evaluate the effect of polymeric coating on product performance, the pellet core structure and composition was kept constant. Four different enteric-coating formulations and designs were evaluated. Enteric-coated drug multiparticulates prepared with single polymeric coatings (acrylic or cellulosic) were compared with two different polymeric layer coatings to evaluate the effectiveness of latter coatings in more effectively producing a better rabeprazole sodium delayed-release pellet product. The pH-dependent, enteric acrylic, and cellulosic polymers were used either alone, in combination, or applied one over the other to impart delayed-release properties to the core drug pellets. It was demonstrated that dual delayed-release coating with two different enteric polymers—an inner acrylic coating followed by an outer cellulosic coating—yields the best product that provides all the desired physicochemical and drug dissolution characteristics. PMID:22171316

  3. A second type of magnitude effect: Reinforcer magnitude differentiates delay discounting between substance users and controls.

    PubMed

    Mellis, Alexandra M; Woodford, Alina E; Stein, Jeffrey S; Bickel, Warren K

    2017-01-01

    Basic research on delay discounting, examining preference for smaller-sooner or larger-later reinforcers, has demonstrated a variety of findings of considerable generality. One of these, the magnitude effect, is the observation that individuals tend to exhibit greater preference for the immediate with smaller magnitude reinforcers. Delay discounting has also proved to be a useful marker of addiction, as demonstrated by the highly replicated finding of greater discounting rates in substance users compared to controls. However, some research on delay discounting rates in substance users, particularly research examining discounting of small-magnitude reinforcers, has not found significant differences compared to controls. Here, we hypothesize that the magnitude effect could produce ceiling effects at small magnitudes, thus obscuring differences in delay discounting between groups. We examined differences in discounting between high-risk substance users and controls over a broad range of magnitudes of monetary amounts ($0.10, $1.00, $10.00, $100.00, and $1000.00) in 116 Amazon Mechanical Turk workers. We found no significant differences in discounting rates between users and controls at the smallest reinforcer magnitudes ($0.10 and $1.00) and further found that differences became more pronounced as magnitudes increased. These results provide an understanding of a second form of the magnitude effect: That is, differences in discounting between populations can become more evident as a function of reinforcer magnitude.

  4. The Effects of Test Trial and Processing Level on Immediate and Delayed Retention

    ERIC Educational Resources Information Center

    Chang, Sau Hou

    2017-01-01

    The purpose of the present study was to investigate the effects of test trial and processing level on immediate and delayed retention. A 2 × 2 × 2 mixed ANOVAs was used with two between-subject factors of test trial (single test, repeated test) and processing level (shallow, deep), and one within-subject factor of final recall (immediate,…

  5. Microarray as a First Genetic Test in Global Developmental Delay: A Cost-Effectiveness Analysis

    ERIC Educational Resources Information Center

    Trakadis, Yannis; Shevell, Michael

    2011-01-01

    Aim: Microarray technology has a significantly higher clinical yield than karyotyping in individuals with global developmental delay (GDD). Despite this, it has not yet been routinely implemented as a screening test owing to the perception that this approach is more expensive. We aimed to evaluate the effect that replacing karyotype with…

  6. The Effect of Learner-Generated Illustrations on the Immediate and Delayed Recall of English Idioms

    ERIC Educational Resources Information Center

    Aeineh, Afrouz; Moeeni, Saeed; Merati, Hamideh

    2014-01-01

    The present study investigated the effect of learner generated illustrations on the immediate and delayed idiom recall of Iranian EFL (English as a foreign language) learners. To accomplish this end, 40 female students participated in this study. A placement test (Quick Placement Test, Version 2) was administered to the participants to ascertain…

  7. The Effects of Test Trial and Processing Level on Immediate and Delayed Retention

    ERIC Educational Resources Information Center

    Chang, Sau Hou

    2013-01-01

    The purpose of the present study was to investigate the effects of test trial and processing level on immediate and delayed retention. Seventy-six college students were randomly assigned first to the single test and the repeated test trials, and then to the shallow processing level and the deep processing level to study forty stimulus words.…

  8. Age of Word Acquisition Effects in Treatment of Children with Phonological Delays

    ERIC Educational Resources Information Center

    Gierut, Judith A.; Morrisette, Michele L.

    2012-01-01

    The effects of the age of acquisition (AoA) of words were examined in the clinical treatment of 10 preschool children with phonological delays. Using a single-subject multiple-baseline experimental design, children were enrolled in one of four conditions that varied the AoA of the treated words (early vs. late acquired) relative to their…

  9. Simultaneous and Delayed Video Modeling: An Examination of System Effectiveness and Student Preferences

    ERIC Educational Resources Information Center

    Taber-Doughyt, Teresa; Patton, Scott E.; Brennan, Stephanie

    2009-01-01

    The effectiveness of simultaneous and delayed video modeling when used by three middle-school students with moderate intellectual disabilities was examined. Alternating between modeling systems, students were taught to use the public library computer to locate specific book call numbers and use the Dewey Decimal Classification System to locate…

  10. Effects of wrapping time delays on the nutritive value of baled alfalfa silages

    USDA-ARS?s Scientific Manuscript database

    Baled silages are an attractive forage conservation option, especially for small and mid-sized beef and dairy producers. Our objectives were to test the effects of delayed wrapping on the nutritive value of baled alfalfa silages on a pre- and post-storage basis. A secondary objective was to evaluate...

  11. Effect of discontinuities on the group delay of a microwave transmission line

    NASA Technical Reports Server (NTRS)

    Beatty, R. W.; Otoshi, T. Y.

    1975-01-01

    The problem is considered of the effect of reflections from discontinuities at each end of a transmission line on the group delay at microwave frequencies. Previous work is briefly reviewed and a general analysis is made. Graphical data are presented based upon the formulas developed. Experimental results are given which confirm the theory.

  12. Electron correlation effects on photoionization time delay in atomic Ar and Xe

    NASA Astrophysics Data System (ADS)

    Ganesan, A.; Saha, S.; Decshmukh, P. C.; Manson, S. T.; Kheifets, A. S.

    2016-05-01

    Time delay studies in photoionization processes have stimulated much interest as they provide valuable dynamical information about electron correlation and relativistic effects. In a recent work on Wigner time delay in the photoionization of noble gas atoms, it was found that correlations resulting from interchannel coupling involving shells with different principal quantum numbers have significant effects on 2s and 2p photoionization of Ne, 3s photoionization of Ar, and 3d photoionization of Kr. In the present work, photoionization time delay in inner and outer subshells of the noble gases Ar and Xe are examined by including electron correlations using different many body techniques: (i) the relativistic-random-phase approximation (RRPA), (ii) RRPA with relaxation, to include relaxation effects of the residual ion and (iii) the relativistic multiconfiguration Tamm-Dancoff (RMCTD) approximation. The (sometimes substantial) effects of the inclusion of non-RPA correlations on the photoionization Wigner time delay are reported. Work supported by DOE, Office of Chemical Sciences and DST (India).

  13. Effects of Spaced Training in Creative Imagination and Delayed Posttesting on Originality.

    ERIC Educational Resources Information Center

    Masten, William G.; Hairston, Susan A.

    While there is increasing evidence that creativity can be improved through training, the spacing of the training has not been studied. This study assessed the effect of spaced training on the use of creative imagination in 110 undergraduate students. The research design was a randomized delayed posttest-only design. The independent variable was…

  14. Effect of discontinuities on the group delay of a microwave transmission line

    NASA Technical Reports Server (NTRS)

    Beatty, R. W.; Otoshi, T. Y.

    1975-01-01

    The problem is considered of the effect of reflections from discontinuities at each end of a transmission line on the group delay at microwave frequencies. Previous work is briefly reviewed and a general analysis is made. Graphical data are presented based upon the formulas developed. Experimental results are given which confirm the theory.

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

    SciTech Connect

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

    1993-12-03

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

  16. UAS Air Traffic Controller Acceptability Study-2: Effects of Communications Delays and Winds in Simulation

    NASA Technical Reports Server (NTRS)

    Comstock, James R., Jr.; Ghatas, Rania W.; Consiglio, Maria C.; Chamberlain, James P.; Hoffler, Keith D.

    2016-01-01

    This study evaluated the effects of Communications Delays and Winds on Air Traffic Controller ratings of acceptability of horizontal miss distances (HMDs) for encounters between UAS and manned aircraft in a simulation of the Dallas-Ft. Worth East-side airspace. Fourteen encounters per hour were staged in the presence of moderate background traffic. Seven recently retired controllers with experience at DFW served as subjects. Guidance provided to the UAS pilots for maintaining a given HMD was provided by information from self-separation algorithms displayed on the Multi-Aircraft Simulation System. Winds tested did not affect the acceptability ratings. Communications delays tested included 0, 400, 1200, and 1800 msec. For longer communications delays, there were changes in strategy and communications flow that were observed and reported by the controllers. The aim of this work is to provide useful information for guiding future rules and regulations applicable to flying UAS in the NAS.

  17. Effects of predator functional diversity on grassland ecosystem function.

    PubMed

    Schmitz, Oswald J

    2009-09-01

    Predator species individually are known to have important effects on plant communities and ecosystem functions such as production, decomposition, and elemental cycling, the nature of which is determined by a key functional trait, predator hunting mode. However, it remains entirely uncertain how predators with different hunting modes combine to influence ecosystem function. I report on an experiment conducted in a New England grassland ecosystem that quantified the net effects of a sit-and-wait and an actively hunting spider species on the plant composition and functioning of a New England grassland ecosystem. I manipulated predator functional diversity by varying the dominance ratio of the two predator species among five treatments using a replacement series design. Experimentation revealed that predator functional diversity effects propagated down the live plant-based chain to affect the levels of plant diversity, and plant litter quality, elemental cycling, and production. Moreover, many of these effects could be approximately by the weighted average of the individual predator species effects, suggesting that this kind of predator diversity effect on ecosystems is not highly nonlinear.

  18. Resource-consumer diversity: testing the effects of leaf litter species diversity on stream macroinvertebrate communities.

    Treesearch

    John S. Kominoski; Catherine M. Pringle

    2009-01-01

    1. Understanding relationships between resource and consumer diversity is essential to predicting how changes in resource diversity might affect several trophic levels and overall ecosystem functioning...

  19. Multiscale Analysis of Effects of Additive and Multiplicative Noise on Delay Differential Equations Near a Bifurcation Point

    NASA Astrophysics Data System (ADS)

    Klosek, M. M.

    2004-04-01

    We study effects of noisy and deterministic perturbations on oscillatory solutions to delay differential equations. We develop the multiscale technique and derive amplitude equations for noisy oscillations near a critical delay. We investigate effects of additive and multiplicative noise. We show that if the magnitudes of noise and deterministic perturbations are balanced, then the oscillatory behavior persists for long times being sustained by the noise. We illustrate the technique and its results on linear and logistic delay equations.

  20. Effect of delayed polymerization time and bracket manipulation on orthodontic bracket bonding

    NASA Astrophysics Data System (ADS)

    Ponikvar, Michael J.

    This study examined the effect of bracket manipulation in combination with delayed polymerization times on orthodontic bracket shear bond strength and degree of resin composite conversion. Orthodontics brackets were bonded to extracted third molars in a simulated oral environment after a set period of delayed polymerization time and bracket manipulation. After curing the bracket adhesive, each bracket underwent shear bond strength testing followed by micro-Raman spectroscopy analysis to measure the degree of conversion of the resin composite. Results demonstrated the shear bond strength and the degree of conversion of ceramic brackets did not vary over time. However, with stainless steel brackets there was a significant effect (p ≤ 0.05) of delay time on shear bond strength between the 0.5 min and 10 min bracket groups. In addition, stainless steel brackets showed significant differences related to degree of conversion over time between the 0.5 min and 5 min groups, in addition to the 0.5 min and 10 min groups. This investigation suggests that delaying bracket adhesive polymerization up to a period of 10 min then adjusting the orthodontic bracket may increase both shear bond strength and degree of conversion of stainless steel brackets while having no effect on ceramic brackets.

  1. Cutaneous tube ureterostomy: a fast and effective method of urinary diversion in emergency situations

    PubMed Central

    Abdin, Tamer; Zamir, Gideon; Pikarsky, Alon; Katz, Ran; Landau, Ezekiel H; Gofrit, Ofer N

    2015-01-01

    Aim To report on a simple and rapid method of urinary diversion. This method was applied successfully in different clinical scenarios when primary reconstruction of the ureters was not possible. Materials and methods The disconnected ureter is catheterized by a feeding tube. The tube is secured with sutures and brought out to the lateral abdominal wall as cutaneous tube ureterostomy (CTU). Results This method was applied in three different clinical scenarios: a 40-year-old man who sustained multiple high-velocity gunshots to the pelvis with combined rectal and bladder trigone injuries and massive bleeding from a comminuted pubic fracture. Damage control included colostomy and bilateral CTUs. A 26-year-old woman had transection of the right lower ureter during abdominal hysterectomy. Diagnosis was delayed for 3 weeks when the patient developed sepsis. The right kidney was diverted with a CTU. A 37-year-old male suffered from bladder perforation and hemorrhagic shock. Emergency cystectomy was done and urinary diversion was accomplished with bilateral CTUs. In all cases, effective drainage of the urinary system was achieved with normalization of kidney function. Conclusion When local or systemic conditions preclude definitive repair and damage control surgery is needed, CTU provides fast and effective urinary diversion. PMID:26090343

  2. Delayed conifer mortality after fuel reduction treatments: Interactive effects of fuel, fire intensity, and bark beetles

    USGS Publications Warehouse

    Youngblood, A.; Grace, J.B.; Mciver, J.D.

    2009-01-01

    Many low-elevation dry forests of the western United States contain more small trees and fewer large trees, more down woody debris, and less diverse and vigorous understory plant communities compared to conditions under historical fire regimes. These altered structural conditions may contribute to increased probability of unnaturally severe wildfires, susceptibility to uncharacteristic insect outbreaks, and drought-related mortality. Broad-scale fuel reduction and restoration treatments are proposed to promote stand development on trajectories toward more sustainable structures. Little research to date, however, has quantified the effects of these treatments on the ecosystem, especially delayed and latent tree mortality resulting directly or indirectly from treatments. In this paper, we explore complex hypotheses relating to the cascade of effects that influence ponderosa pine (Pinus ponderosa) and Douglas-fir (Pseudotsuga menziesii) mortality using structural equation modeling (SEM). We used annual census and plot data through six growing seasons after thinning and four growing seasons after burning from a replicated, operational-scale, completely randomized experiment conducted in northeastern Oregon, USA, as part of the national Fire and Fire Surrogate study. Treatments included thin, burn, thin followed by burn (thin+burn), and control. Burn and thin+burn treatments increased the proportion of dead trees while the proportion of dead trees declined or remained constant in thin and control units, although the density of dead trees was essentially unchanged with treatment. Most of the new mortality (96%) occurred within two years of treatment and was attributed to bark beetles. Bark beetle-caused tree mortality, while low overall, was greatest in thin + burn treatments. SEM results indicate that the probability of mortality of large-diameter ponderosa pine from bark beetles and wood borers was directly related to surface fire severity and bole charring, which in

  3. Criterial Noise Effects on Rule-Based Category Learning: The Impact of Delayed Feedback

    PubMed Central

    Ell, Shawn; Ing, A. David; Maddox, W. Todd

    2009-01-01

    Variability in the representation of the decision criterion is assumed in many category learning models yet few studies have directly examined its impact. On each trial, criterial noise should result in drift in the criterion and will negatively impact categorization accuracy, particularly in rule-based categorization tasks where learning depends upon the maintenance and manipulation of decision criteria. The results of three experiments test this hypothesis and examine the impact of working memory on slowing the drift rate. Experiment 1 examined the effect of drift by inserting a 5 s delay between the categorization response and the delivery of corrective feedback, and working memory demand was manipulated by varying the number of decision criteria to be learned. Delayed feedback adversely affected performance, but only when working memory demand was high. Experiment 2 built upon a classic finding in the absolute identification literature and demonstrated that distributing the criteria across multiple dimensions decreases the impact of drift during the delay. Experiment 3 confirmed that the effect of drift during the delay is moderated by working memory. These results provide important insights into the interplay between criterial noise and working memory as well as providing important constraints for models of rule-based category learning. PMID:19633342

  4. Adaptation to delayed auditory feedback induces the temporal recalibration effect in both speech perception and production.

    PubMed

    Yamamoto, Kosuke; Kawabata, Hideaki

    2014-12-01

    We ordinarily speak fluently, even though our perceptions of our own voices are disrupted by various environmental acoustic properties. The underlying mechanism of speech is supposed to monitor the temporal relationship between speech production and the perception of auditory feedback, as suggested by a reduction in speech fluency when the speaker is exposed to delayed auditory feedback (DAF). While many studies have reported that DAF influences speech motor processing, its relationship to the temporal tuning effect on multimodal integration, or temporal recalibration, remains unclear. We investigated whether the temporal aspects of both speech perception and production change due to adaptation to the delay between the motor sensation and the auditory feedback. This is a well-used method of inducing temporal recalibration. Participants continually read texts with specific DAF times in order to adapt to the delay. Then, they judged the simultaneity between the motor sensation and the vocal feedback. We measured the rates of speech with which participants read the texts in both the exposure and re-exposure phases. We found that exposure to DAF changed both the rate of speech and the simultaneity judgment, that is, participants' speech gained fluency. Although we also found that a delay of 200 ms appeared to be most effective in decreasing the rates of speech and shifting the distribution on the simultaneity judgment, there was no correlation between these measurements. These findings suggest that both speech motor production and multimodal perception are adaptive to temporal lag but are processed in distinct ways.

  5. The effects of time delay in man-machine control systems: Implications for design of flight simulator Visual-Display-Delay compensation

    NASA Technical Reports Server (NTRS)

    Crane, D. F.

    1984-01-01

    When human operators are performing precision tracking tasks, their dynamic response can often be modeled by quasilinear describing functions. That fact permits analysis of the effects of delay in certain man machine control systems using linear control system analysis techniques. The analysis indicates that a reduction in system stability is the immediate effect of additional control system delay, and that system characteristics moderate or exaggerate the importance of the delay. A selection of data (simulator and flight test) consistent with the analysis is reviewed. Flight simulator visual-display delay compensation, designed to restore pilot aircraft system stability, was evaluated in several studies which are reviewed here. The studies range from single-axis, tracking-task experiments (with sufficient subjects and trials to establish the statistical significance of the results) to a brief evaluation of compensation of a computer generated imagery (CGI) visual display system in a full six degree of freedom simulation. The compensation was effective, improvements in pilot performance and workload or aircraft handling qualities rating (HQR) were observed. Results from recent aircraft handling qualities research literature, which support the compensation design approach, are also reviewed.

  6. The effects of time delay in man-machine control systems: Implications for design of flight simulator Visual-Display-Delay compensation

    NASA Technical Reports Server (NTRS)

    Crane, D. F.

    1984-01-01

    When human operators are performing precision tracking tasks, their dynamic response can often be modeled by quasilinear describing functions. That fact permits analysis of the effects of delay in certain man machine control systems using linear control system analysis techniques. The analysis indicates that a reduction in system stability is the immediate effect of additional control system delay, and that system characteristics moderate or exaggerate the importance of the delay. A selection of data (simulator and flight test) consistent with the analysis is reviewed. Flight simulator visual-display delay compensation, designed to restore pilot aircraft system stability, was evaluated in several studies which are reviewed here. The studies range from single-axis, tracking-task experiments (with sufficient subjects and trials to establish the statistical significance of the results) to a brief evaluation of compensation of a computer generated imagery (CGI) visual display system in a full six degree of freedom simulation. The compensation was effective, improvements in pilot performance and workload or aircraft handling qualities rating (HQR) were observed. Results from recent aircraft handling qualities research literature, which support the compensation design approach, are also reviewed.

  7. Incorporating plant functional diversity effects in ecosystem service assessments.

    PubMed

    Díaz, Sandra; Lavorel, Sandra; de Bello, Francesco; Quétier, Fabien; Grigulis, Karl; Robson, T Matthew

    2007-12-26

    Global environmental change affects the sustained provision of a wide set of ecosystem services. Although the delivery of ecosystem services is strongly affected by abiotic drivers and direct land use effects, it is also modulated by the functional diversity of biological communities (the value, range, and relative abundance of functional traits in a given ecosystem). The focus of this article is on integrating the different possible mechanisms by which functional diversity affects ecosystem properties that are directly relevant to ecosystem services. We propose a systematic way for progressing in understanding how land cover change affects these ecosystem properties through functional diversity modifications. Models on links between ecosystem properties and the local mean, range, and distribution of plant trait values are numerous, but they have been scattered in the literature, with varying degrees of empirical support and varying functional diversity components analyzed. Here we articulate these different components in a single conceptual and methodological framework that allows testing them in combination. We illustrate our approach with examples from the literature and apply the proposed framework to a grassland system in the central French Alps in which functional diversity, by responding to land use change, alters the provision of ecosystem services important to local stakeholders. We claim that our framework contributes to opening a new area of research at the interface of land change science and fundamental ecology.

  8. The effect of visual-motion time-delays on pilot performance in a simulated pursuit tracking task

    NASA Technical Reports Server (NTRS)

    Miller, G. K., Jr.; Riley, D. R.

    1977-01-01

    An experimental study was made to determine the effect on pilot performance of time delays in the visual and motion feedback loops of a simulated pursuit tracking task. Three major interrelated factors were identified: task difficulty either in the form of airplane handling qualities or target frequency, the amount and type of motion cues, and time delay itself. In general, the greater the task difficulty, the smaller the time delay that could exist without degrading pilot performance. Conversely, the greater the motion fidelity, the greater the time delay that could be tolerated. The effect of motion was, however, pilot dependent.

  9. Is delayed ischemic preconditioning as effective on running performance during a 5km time trial as acute IPC?

    PubMed

    Seeger, Joost P H; Timmers, Silvie; Ploegmakers, Danique J M; Cable, N Timothy; Hopman, Maria T E; Thijssen, Dick H J

    2017-02-01

    Ischemic preconditioning (IPC) may enhance exercise performance. Cardioprotective effects of IPC are known to re-occur 24h after the stimulus. Whether the delayed effect of IPC has similar effects as IPC on exercise performance is unknown.

  10. A Job with a Future? Delay Discounting, Magnitude Effects, and Domain Independence of Utility for Career Decisions.

    ERIC Educational Resources Information Center

    Schoenfelder, Thomas E.; Hantula, Donald A.

    2003-01-01

    Seniors (n=20) assessed two job offers with differences in domain (salary/tasks), delay (career-long earnings), and magnitude (initial salary offer). Contrary to discounted utility theory, choices reflected nonconstant discount rates for future salary/tasks (delay effect), lower discount rates for salary/preferred tasks (magnitude effect), and a…

  11. A Job with a Future? Delay Discounting, Magnitude Effects, and Domain Independence of Utility for Career Decisions.

    ERIC Educational Resources Information Center

    Schoenfelder, Thomas E.; Hantula, Donald A.

    2003-01-01

    Seniors (n=20) assessed two job offers with differences in domain (salary/tasks), delay (career-long earnings), and magnitude (initial salary offer). Contrary to discounted utility theory, choices reflected nonconstant discount rates for future salary/tasks (delay effect), lower discount rates for salary/preferred tasks (magnitude effect), and a…

  12. Methylphenidate and impulsivity: a comparison of effects of methylphenidate enantiomers on delay discounting in rats.

    PubMed

    Slezak, Jonathan M; Ricaurte, George A; Tallarida, Ronald J; Katz, Jonathan L

    2014-01-01

    Current formulations of methylphenidate (MPH) used in treatment of attention-deficit/hyperactivity disorder (ADHD) result in significantly different bioavailability of MPH enantiomers. Daytrana®, a dl-MPH transdermal patch system, produces higher levels of l-MPH than when dl-MPH is administered orally (e.g., Ritalin®). One potential limitation of increased l-MPH was indicated in a preclinical study showing l-MPH may attenuate effects of d-MPH. The objective of the study was to investigate the interactive effects of MPH enantiomers by (1) assessing drug effects via a preclinical model of "impulsivity" and (2) performing a quantitative dose equivalence analysis of MPH enantiomer interactions. Sprague-Dawley rats were trained to emit either of two responses, one producing an immediate food pellet, the other producing four pellets delivered at increasing delays (0, 8, and 32 s). The percent selection of the larger food amount was graphed as a function of delay with the area under the curve (AUC) assessed. Increases in AUC are consistent with decreases in "impulsivity" (i.e., selection of the smaller, immediate over the larger, delayed reinforcer). Systemic administration of dl-MPH and d-MPH dose-dependently increased AUC, while l-MPH, morphine, and pentobarbital did not alter AUC. An analysis based upon dose equivalence indicated that dl-MPH produced additive effects that were not different from that predicted from effects of the enantiomers administered alone. The present results indicate pharmacologically selective effects in that only drugs prescribed for the treatment of ADHD symptoms decreased a measure of "impulsivity" and that l-MPH likely does not attenuate or enhance the effects of d-MPH in the current delay-discounting task.

  13. Delayed auditory feedback effects during reading and conversation tasks: gender differences in fluent adults.

    PubMed

    Corey, David M; Cuddapah, Vishnu Anand

    2008-12-01

    Delayed auditory feedback (DAF) impacts the speech fluency of normally fluent males more than that of normally fluent females. Understanding this gender difference may contribute to our understanding of gender differences in the prevalence of developmental stuttering. To characterize this gender difference in fluent people, DAF-induced dysfluency was measured in 20 male and 21 female young adults during oral reading and conversation tasks. Stutter-like dysfluencies (SLDs), articulation errors, interjections, reading errors, and speech rate were measured for both speech tasks as the participant spoke without feedback, with non-delayed feedback, and with DAF presented with 5 delay intervals (14 conditions total). DAF induced SLDs (but not other dysfluencies) more frequently during conversation than reading, and this effect was significantly greater for males than females (Gender x Task x Feedback interaction). Males also produced significantly more reading errors than females. DAF reduced speaking rate significantly more while reading than conversing (Task x Feedback interaction). DAF significantly decreased the frequency of interjections and increased the frequency of articulation errors; however, no Gender effects on these variables were observed. Although significant order effects indicated improved fluency across trials, covariance analysis suggested that order effects could not explain other results. After reading this article, the reader will be able to (1) Discuss developmental stuttering (DS) and gender differences in DS prevalence. (2) Define delayed auditory feedback (DAF). (3) Evaluate the evidence that gender is linked to DAF effects on fluent people. (4) Summarize the results of new research designed to assess sex differences in DAF effects on speech fluency in normally fluent adults. (5) Evaluate the degree to which evidence from the literature indicating that individual differences in attentional control may help us understand gender difference in DAF

  14. Quantification of the effects of chlorpromazine on performance under delayed matching to sample in pigeons.

    PubMed

    Watson, J E; Blampied, N M

    1989-05-01

    The effects of four doses of chlorpromazine (dose range 0.5 to 12.5 mg/kg) on performance under a delayed matching-to-sample procedure in pigeons was investigated, using the exponential model of memory (White, 1985). Performance was measured using a bias-free measure of discriminability, log d (Davison & Tustin, 1978), and negative exponential functions were fitted to individual-subject and group data at each dose level. A decrease in matching accuracy was found to be caused by an increase in the rate of forgetting, b, and a decrease in the initial discriminability, log d0. Changes in rate of forgetting and discriminability occurred at doses that had no statistically significant effect on response latency. The exponential model of memory accounted well for the data and provided a useful way of quantifying the effects of chlorpromazine on the processes involved in delayed matching-to-sample performance.

  15. Tracking with asymptotic sliding mode and adaptive input delay effect compensation of nonlinearly perturbed delayed systems applied to traffic feedback control

    NASA Astrophysics Data System (ADS)

    Mirkin, Boris; Haddad, Jack; Shtessel, Yuri

    2016-09-01

    Asymptotical sliding mode-model reference adaptive control design for a class of systems with parametric uncertainty, unknown nonlinear perturbation and external disturbance, and with known input and state delays is proposed. To overcome the difficulty to directly predict the plant state under uncertainties, a control design is based on a developed decomposition procedure, where a 'generalised error' in conjunction with auxiliary linear dynamic blocks with adjustable gains is introduced and the sliding variable is formed on the basis of this error. The effect of such a decomposition is to pull the input delay out of first step of the design procedure. As a result, similarly to the classical Smith predictor, the adaptive control architecture based only on the lumped-delays, i.e. without conventional in such cases difficult-implemented distributed-delay blocks. Two new adaptive control schemes are proposed. A linearisation-based control design is constructed for feedback control of an urban traffic region model with uncertain dynamics. Simulation results demonstrate the effectiveness of the developed adaptive control method.

  16. The effect of topical minoxidil pretreatment on nonsurgical delay of rat cutaneous flaps: further studies.

    PubMed

    Gümüş, Nazım; Odemiş, Yusuf; Tuncer, Ersin; Yılmaz, Sarper

    2013-08-01

    The purpose of this study was to determine the effectiveness of topically applied minoxidil in the pharmacological delay phenomenon and to demonstrate the comparable microscopic and macroscopic changes between minoxidil-pretreated flaps and surgically delayed flaps. A modified version of the McFarlane flap was used. Group 1 rats, in which a caudally based dorsal skin flap was raised and sutured back, were the control group. In group II, minoxidil solution was spread over the marked skin flap area for 7 days. On the 7th day, a caudally based dorsal skin flap was elevated and then sutured back. Group III rats underwent a surgical delay procedure alone. On the 7th day after flap elevation, evaluation was done by histologic examination and calculation of the flap survival areas in all groups. The lowest flap survival rate appeared in group I and was statistically different from groups II and III. The mean surviving skin flap area in the minoxidil-pretreated group was significantly larger than that in the control group. After histologic evaluation, moderate angiogenesis was also detected in group II. We also found that surgical delay significantly reduced flap necrosis when compared to the minoxidil pretreatment group. According to our study, minoxidil may be considered an effective vasoactive agent for the stimulation of angiogenesis in rat cutaneous flaps and capable of achieving pharmacological delay and increasing flap survival. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

  17. Effects of antibiotic administration delay and inadequacy upon the survival of septic shock patients.

    PubMed

    Suberviola Cañas, B; Jáuregui, R; Ballesteros, M Á; Leizaola, O; González-Castro, A; Castellanos-Ortega, Á

    2015-11-01

    To assess how antibiotic administration delay and inadequacy influence survival in septic shock patients. A prospective, observational cohort study was carried out between September 2005 and September 2010. Patients admitted to the ICU of a third level hospital. A total of 342 septic shock patients None The time to antibiotic administration (difference between septic shock presentation and first administered dose of antibiotic) and its adequacy (in vitro susceptibility testing of isolated pathogens) were determined. ICU and hospital mortality were 26.4% and 33.5%, respectively. The median delay to administration of the first antibiotic dose was 1.7h. Deceased patients received antibiotics significantly later than survivors (1.3±14.5h vs. 5.8±18.02h; P=.001). Percentage drug inadequacy was 12%. Those patients who received inadequate antibiotics had significantly higher mortality rates (33.8% vs. 51.2%; P=.03). The coexistence of treatment delay and inadequacy was associated to lower survival rates. Both antibiotic administration delay and inadequacy exert deleterious effects upon the survival of septic shock patients, independently of their characteristics or severity. Copyright © 2015 Elsevier España, S.L.U. and SEMICYUC. All rights reserved.

  18. Dual effectiveness of lithium salt in controlling both delayed ettringite formation and ASR in concretes

    SciTech Connect

    Ekolu, S.O. . E-mail: stephen.ekolu@wits.ac.za; Thomas, M.D.A.; Hooton, R.D.

    2007-06-15

    The influence of lithium nitrate on expansions due to delayed ettringite formation (DEF) and alkali-silica reaction (ASR) has been investigated. Effects of the lithium salt were examined in heat-cured mortars and concretes containing one or both damage mechanisms. The mortars and concretes made using reactive and/or non-reactive aggregates were subjected to heat treatment consisting of a hydration delay period of 4 h at 23 deg. C followed by steam-curing at 95 deg. C and then stored in limewater. Results showed that the lithium salt admixture was able to reduce the occurrence of deleterious expansion due to delayed ettringite formation in addition to controlling alkali-silica reaction in cementitious systems containing one or both mechanisms. In concretes made using non-reactive limestone aggregates, incorporation of lithium nitrate in a proportion of 0.74 M ratio of Li to (Na + K) was found to control delayed ettringite formation during the one-year period of this study. By analyzing the leaching properties of lithium and other alkalis from mortars during storage, it was found that a substantial amount of lithium was retained in the cementitious system in a slightly soluble form, and is expected to be responsible for reducing DEF.

  19. Does Socioeconomic Diversity Make a Difference? Examining the Effects of Racial and Socioeconomic Diversity on the Campus Climate for Diversity

    ERIC Educational Resources Information Center

    Park, Julie J.; Denson, Nida; Bowman, Nicholas A.

    2013-01-01

    This article considers whether the socioeconomic diversity of the undergraduate student body and experiences with cross-class interaction (CCI) are significantly related to cross-racial interaction (CRI) and engagement with curricular/co-curricular diversity (CCD) activities. Individual students who reported higher levels of CCI had significantly…

  20. Does Socioeconomic Diversity Make a Difference? Examining the Effects of Racial and Socioeconomic Diversity on the Campus Climate for Diversity

    ERIC Educational Resources Information Center

    Park, Julie J.; Denson, Nida; Bowman, Nicholas A.

    2013-01-01

    This article considers whether the socioeconomic diversity of the undergraduate student body and experiences with cross-class interaction (CCI) are significantly related to cross-racial interaction (CRI) and engagement with curricular/co-curricular diversity (CCD) activities. Individual students who reported higher levels of CCI had significantly…

  1. Toilet Training Children With Autism and Developmental Delays: An Effective Program for School Settings

    PubMed Central

    Cocchiola, Michael A.; Martino, Gayle M.; Dwyer, Lisa J.; Demezzo, Kelly

    2012-01-01

    Current research literature on toilet training for children with autism or developmental delays focuses on smaller case studies, typically with concentrated clinical support. Limited research exists to support an effective school-based program to teach toileting skills implemented by public school staff. We describe an intervention program to toilet train 5 children with autism or developmental delays who demonstrated no prior success in the home or school setting. Intervention focused on (a) removal of diapers during school hours, (b) scheduled time intervals for bathroom visits, (c) a maximum of 3 min sitting on the toilet, (d) reinforcers delivered immediately contingent on urination in the toilet, and (e) gradually increased time intervals between bathroom visits as each participant met mastery during the preceding, shorter time interval. The program was effective across all 5 cases in a community-based elementary school. Paraprofessional staff implemented the program with minimal clinical oversight. PMID:23730467

  2. Effects of Delayed Cord Clamping in Very Low Birth Weight Infants

    PubMed Central

    Oh, William; Fanaroff, Avroy A.; Carlo, Waldemar A.; Donovan, Edward F.; McDonald, Scott A.; Poole, W. Kenneth

    2012-01-01

    Background Delayed cord clamping may be beneficial in very preterm and low birth weight infants. Study Design A randomized unmasked controlled trial Setting The study was performed in three centers of the NICHD Neonatal Research Network Hypothesis Delayed cord clamping in very preterm and very low birth weight infants will result in an increase in hematocrit at 4 hours of age. Methods Infants with a gestational age of 24-28 weeks were randomized into early (< 10 seconds) or delayed (30-45 seconds) cord clamping. The primary outcome was venous hematocrit at 4 hours of age. Secondary outcomes included delivery room management, selected neonatal morbidities and the need for blood transfusion during the infants’ hospital stay. Results Thirty three infants were randomized: 17 to the immediate cord clamping (ICC, cord clamped at 7.9 ± 5.2 seconds, m±SD) and 16 to the delayed cord clamping (DCC, cord clamped at 35.2 ± 10.1 seconds) group. The hematocrit was higher in the DCC group (45 ± 8 versus 40 ± 5%, p<0.05). The frequency of events during delivery room resuscitation was almost identical between the two groups. There was no difference in hourly mean arterial blood pressure during the first 12 hours of life, there was a trend in the difference in the incidence of selected neonatal morbidities, hematocrit at 2, 4 and 6 weeks as well as the need for transfusion, but none of the differences was statistically significant Conclusion A higher hematocrit is achieved by delayed cord clamping in very low birth weight infants suggesting effective placental transfusion. PMID:21448208

  3. Interferometric Propagation Delay

    NASA Technical Reports Server (NTRS)

    Goldstein, Richard

    1999-01-01

    Radar interferometry based on (near) exact repeat passes has lately been used by many groups of scientists, worldwide, to achieve state of the art measurements of topography, glacier and ice stream motion, earthquake displacements, oil field subsidence, lava flows, crop-induced surface decorrelation, and other effects. Variations of tropospheric and ionospheric propagation delays limit the accuracy of all such measurements. We are investigating the extent of this limitation, using data from the Shuttle radar flight, SIR-C, which is sensitive to the troposphere, and the Earth Resources Satellites, ERS-1/2, which are sensitive to both the troposphere and the ionosphere. We are presently gathering statistics of the delay variations over selected, diverse areas to determine the best accuracy possible for repeat track interferometry. The phases of an interferogram depend on both the topography of the scene and variations in propagation delay. The delay variations can be caused by movement of elements in the scene, by changes in tropospheric water vapor and by changes of the charge concentrations in the ionosphere. We plan to separate these causes by using the data from a third satellite visit (three-pass interferometry). The figure gives the geometry of the three-pass observations. The page of the figure is taken to be perpendicular to the spacecraft orbits. The three observational locations are marked on the figure, giving baselines B-12 and B-13, separated by the angle alpha. These parameters are almost constant over the whole scene. However, each pixel has an individual look angle, theta, which is related to the topography, rho is the slant range. A possible spurious time delay is shown. Additional information is contained in the original.

  4. Interferometric Propagation Delay

    NASA Technical Reports Server (NTRS)

    Goldstein, Richard

    1999-01-01

    Radar interferometry based on (near) exact repeat passes has lately been used by many groups of scientists, worldwide, to achieve state of the art measurements of topography, glacier and ice stream motion, earthquake displacements, oil field subsidence, lava flows, crop-induced surface decorrelation, and other effects. Variations of tropospheric and ionospheric propagation delays limit the accuracy of all such measurements. We are investigating the extent of this limitation, using data from the Shuttle radar flight, SIR-C, which is sensitive to the troposphere, and the Earth Resources Satellites, ERS-1/2, which are sensitive to both the troposphere and the ionosphere. We are presently gathering statistics of the delay variations over selected, diverse areas to determine the best accuracy possible for repeat track interferometry. The phases of an interferogram depend on both the topography of the scene and variations in propagation delay. The delay variations can be caused by movement of elements in the scene, by changes in tropospheric water vapor and by changes of the charge concentrations in the ionosphere. We plan to separate these causes by using the data from a third satellite visit (three-pass interferometry). The figure gives the geometry of the three-pass observations. The page of the figure is taken to be perpendicular to the spacecraft orbits. The three observational locations are marked on the figure, giving baselines B-12 and B-13, separated by the angle alpha. These parameters are almost constant over the whole scene. However, each pixel has an individual look angle, theta, which is related to the topography, rho is the slant range. A possible spurious time delay is shown. Additional information is contained in the original.

  5. The effect of reinforcer magnitude on probability and delay discounting of experienced outcomes in a computer game task in humans.

    PubMed

    Greenhow, Anna K; Hunt, Maree J; Macaskill, Anne C; Harper, David N

    2015-09-01

    Delay and uncertainty of receipt both reduce the subjective value of reinforcers. Delay has a greater impact on the subjective value of smaller reinforcers than of larger ones while the reverse is true for uncertainty. We investigated the effect of reinforcer magnitude on discounting of delayed and uncertain reinforcers using a novel approach: embedding relevant choices within a computer game. Participants made repeated choices between smaller, certain, immediate outcomes and larger, but delayed or uncertain outcomes while experiencing the result of each choice. Participants' choices were generally well described by the hyperbolic discounting function. Smaller numbers of points were discounted more steeply than larger numbers as a function of delay but not probability. The novel experiential choice task described is a promising approach to investigating both delay and probability discounting in humans.

  6. Time Delay Effect in a Living Coupled Oscillator System with the Plasmodium of Physarum polycephalum

    NASA Astrophysics Data System (ADS)

    Takamatsu, Atsuko; Fujii, Teruo; Endo, Isao

    2000-08-01

    A living coupled oscillator system was constructed by a cell patterning method with a plasmodial slime mold, in which parameters such as coupling strength and distance between the oscillators can be systematically controlled. Rich oscillation phenomena between the two-coupled oscillators, namely, desynchronizing and antiphase/in-phase synchronization were observed according to these parameters. Both experimental and theoretical approaches showed that these phenomena are closely related to the time delay effect in interactions between the oscillators.

  7. Cost-effectiveness of emergency versus delayed laparoscopic cholecystectomy for acute gallbladder pathology.

    PubMed

    Sutton, A J; Vohra, R S; Hollyman, M; Marriott, P J; Buja, A; Alderson, D; Pasquali, S; Griffiths, E A

    2017-01-01

    The optimal timing of cholecystectomy for patients admitted with acute gallbladder pathology is unclear. Some studies have shown that emergency cholecystectomy during the index admission can reduce length of hospital stay with similar rates of conversion to open surgery, complications and mortality compared with a 'delayed' operation following discharge. Others have reported that cholecystectomy during the index acute admission results in higher morbidity, extended length of stay and increased costs. This study examined the cost-effectiveness of emergency versus delayed cholecystectomy for acute benign gallbladder disease. Using data from a prospective population-based cohort study examining the outcomes of cholecystectomy in the UK and Ireland, a model-based cost-utility analysis was conducted from the perspective of the UK National Health Service, with a 1-year time horizon for costs and outcomes. Probabilistic sensitivity analysis was used to investigate the impact of parameter uncertainty on the results obtained from the model. Emergency cholecystectomy was found to be less costly (£4570 versus £4720; €5484 versus €5664) and more effective (0·8868 versus 0·8662 QALYs) than delayed cholecystectomy. Probabilistic sensitivity analysis showed that the emergency strategy is more than 60 per cent likely to be cost-effective across willingness-to-pay values for the QALY from £0 to £100 000 (€0-120 000). Emergency cholecystectomy is less costly and more effective than delayed cholecystectomy. This approach is likely to be beneficial to patients in terms of improved health outcomes and to the healthcare provider owing to the reduced costs. © 2016 BJS Society Ltd Published by John Wiley & Sons Ltd.

  8. The Effect of Delay in the Presentation of Visual Information on Pilot Performance

    DTIC Science & Technology

    1975-12-01

    Norrington CDR T . E. Curry Lt. Col. J. G. Cowart Maj. E. Bodenheimer Capt. J. Jordan LTJG Stan Snavely Mr. Mitchell Bradner Mr. Robert...Submit) The Effect of Delay in the Presentation of Visual Information on Pilot Performance 7. AUTHOR»’«) Fred R. Cooper William T . Harris Vincent J...DISTRIBUTION STATEMEN t (ol thl» Report; Approved for public release; distribution unlimited 17. DISTRIBUTION STATEMENT (ol Ihm abstract nlmd In

  9. Predator diversity, intraguild predation, and indirect effects drive parasite transmission.

    PubMed

    Rohr, Jason R; Civitello, David J; Crumrine, Patrick W; Halstead, Neal T; Miller, Andrew D; Schotthoefer, Anna M; Stenoien, Carl; Johnson, Lucinda B; Beasley, Val R

    2015-03-10

    Humans are altering biodiversity globally and infectious diseases are on the rise; thus, there is interest in understanding how changes to biodiversity affect disease. Here, we explore how predator diversity shapes parasite transmission. In a mesocosm experiment that manipulated predator (larval dragonflies and damselflies) density and diversity, non-intraguild (non-IG) predators that only consume free-living cercariae (parasitic trematodes) reduced metacercarial infections in tadpoles, whereas intraguild (IG) predators that consume both parasites and tadpole hosts did not. This likely occurred because IG predators reduced tadpole densities and anticercarial behaviors, increasing per capita exposure rates of the surviving tadpoles (i.e., via density- and trait-mediated effects) despite the consumption of parasites. A mathematical model demonstrated that non-IG predators reduce macroparasite infections, but IG predation weakens this "dilution effect" and can even amplify parasite burdens. Consistent with the experiment and model, a wetland survey revealed that the diversity of IG predators was unrelated to metacercarial burdens in amphibians, but the diversity of non-IG predators was negatively correlated with infections. These results are strikingly similar to generalities that have emerged from the predator diversity-pest biocontrol literature, suggesting that there may be general mechanisms for pest control and that biocontrol research might inform disease management and vice versa. In summary, we identified a general trait of predators--where they fall on an IG predation continuum--that predicts their ability to reduce infections and possibly pests in general. Consequently, managing assemblages of predators represents an underused tool for the management of human and wildlife diseases and pest populations.

  10. Allee effect promotes diversity in traveling waves of colonization

    PubMed Central

    Roques, Lionel; Garnier, Jimmy; Hamel, François; Klein, Etienne K.

    2012-01-01

    Most mathematical studies on expanding populations have focused on the rate of range expansion of a population. However, the genetic consequences of population expansion remain an understudied body of theory. Describing an expanding population as a traveling wave solution derived from a classical reaction-diffusion model, we analyze the spatio-temporal evolution of its genetic structure. We show that the presence of an Allee effect (i.e., a lower per capita growth rate at low densities) drastically modifies genetic diversity, both in the colonization front and behind it. With an Allee effect (i.e., pushed colonization waves), all of the genetic diversity of a population is conserved in the colonization front. In the absence of an Allee effect (i.e., pulled waves), only the furthest forward members of the initial population persist in the colonization front, indicating a strong erosion of the diversity in this population. These results counteract commonly held notions that the Allee effect generally has adverse consequences. Our study contributes new knowledge to the surfing phenomenon in continuous models without random genetic drift. It also provides insight into the dynamics of traveling wave solutions and leads to a new interpretation of the mathematical notions of pulled and pushed waves. PMID:22611189

  11. Effects of topsoil removal on seedling emergence and species diversity

    SciTech Connect

    Winkel, V.K.; Ostler, W.K.

    1994-02-01

    Approximately 800 hectares on the US Department of Energy Nevada Test Site and vicinity are contaminated with Plutonium. As part of a cleanup effort, both the vegetation and the top 5--10 cm of soil may be removed. A study was developed to determine the effects of topsoil removal on seedling emergence and plant species diversity. Trial plots were prepared by removing 5, 10, or 20 cm of topsoil, seeding a mix of nine native species, mulching with straw, and then anchoring the straw with erosion netting. Additional plots (0 topsoil removal treatment) were lightly bladed to remove existing vegetation and then treated as above. Approximately 85 mm of supplemental irrigation was applied to help initiate germination during early spring. Seedling density data of seeded and nonseeded species was collected following emergence, and species diversity was calculated with the Shannon diversity index for the nonseeded species. Densities of seeded species either were unaffected by or increased with increased depth of topsoil removal. In general, densities of nonseeded species decreased with increased depth of topsoil removal. The number of species, species diversity and evenness also decreased with increased depth of topsoil removal. Initial emergence of seeded species is apparently unaffected by topsoil removal at this site.

  12. Strong Delayed Interactive Effects of Metal Exposure and Warming: Latitude-Dependent Synergisms Persist Across Metamorphosis.

    PubMed

    Debecker, Sara; Dinh, Khuong V; Stoks, Robby

    2017-02-21

    As contaminants are often more toxic at higher temperatures, predicting their impact under global warming remains a key challenge for ecological risk assessment. Ignoring delayed effects, synergistic interactions between contaminants and warming, and differences in sensitivity across species' ranges could lead to an important underestimation of the risks. We addressed all three mechanisms by studying effects of larval exposure to zinc and warming before, during, and after metamorphosis in Ischnura elegans damselflies from high- and low-latitude populations. By integrating these mechanisms into a single study, we could identify two novel patterns. First, during exposure zinc did not affect survival, whereas it induced mild to moderate postexposure mortality in the larval stage and at metamorphosis, and very strongly reduced adult lifespan. This severe delayed effect across metamorphosis was especially remarkable in high-latitude animals, as they appeared almost insensitive to zinc during the larval stage. Second, the well-known synergism between metals and warming was manifested not only during the larval stage but also after metamorphosis, yet notably only in low-latitude damselflies. These results highlight that a more complete life-cycle approach that incorporates the possibility of delayed interactions between contaminants and warming in a geographical context is crucial for a more realistic risk assessment in a warming world.

  13. Neuroprotective effects of silymarin on ischemia-induced delayed neuronal cell death in rat hippocampus.

    PubMed

    Hirayama, Koki; Oshima, Hideki; Yamashita, Akiko; Sakatani, Kaoru; Yoshino, Atsuo; Katayama, Yoichi

    2016-09-01

    We examined the effects of silymarin, which was extracted from Silybum marianum, on delayed neuronal cell death in the rat hippocampus. Rats were divided into four groups: sham-operated rats (sham group), rats which underwent ischemic surgery (control group), rats which were treated with silymarin before and after ischemic surgery (pre group), and rats which were treated with silymarin after ischemic surgery only (post group). We performed the ischemic surgery by occluding the bilateral carotid arteries for 20min and sacrificed the rats one week after the surgery. Silymarin was administered orally at 200mg/kg body weight. Smaller numbers of delayed cell deaths were noted in the rat CA1 region of the pre- and post-groups, and no significant difference was observed between these groups. There were few apoptotic cell deaths in all groups. Compared to the control group, significantly fewer cell deaths by autophagy were found in the pre- and post-group. We concluded that silymarin exerts a preservation effect on delayed neuronal cell death in the rat hippocampus and this effect has nothing to do with the timing of administering of silymarin. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Measurements of effective delayed neutron fraction in a fast neutron reactor using the perturbation method

    NASA Astrophysics Data System (ADS)

    Zhou, Hao-Jun; Yin, Yan-Peng; Fan, Xiao-Qiang; Li, Zheng-Hong; Pu, Yi-Kang

    2016-06-01

    A perturbation method is proposed to obtain the effective delayed neutron fraction β eff of a cylindrical highly enriched uranium reactor. Based on reactivity measurements with and without a sample at a specified position using the positive period technique, the reactor reactivity perturbation Δρ of the sample in β eff units is measured. Simulations of the perturbation experiments are performed using the MCNP program. The PERT card is used to provide the difference dk of effective neutron multiplication factors with and without the sample inside the reactor. Based on the relationship between the effective multiplication factor and the reactivity, the equation β eff = dk/Δρ is derived. In this paper, the reactivity perturbations of 13 metal samples at the designable position of the reactor are measured and calculated. The average β eff value of the reactor is given as 0.00645, and the standard uncertainty is 3.0%. Additionally, the perturbation experiments for β eff can be used to evaluate the reliabilities of the delayed neutron parameters. This work shows that the delayed neutron data of 235U and 238U from G.R. Keepin’s publication are more reliable than those from ENDF-B6.0, ENDF-B7.0, JENDL3.3 and CENDL2.2. Supported by Foundation of Key Laboratory of Neutron Physics, China Academy of Engineering Physics (2012AA01, 2014AA01), National Natural Science Foundation (11375158, 91326104)

  15. Effects of racial diversity on complex thinking in college students.

    PubMed

    Antonio, Anthony Lising; Chang, Mitchell J; Hakuta, Kenji; Kenny, David A; Levin, Shana; Milem, Jeffrey F

    2004-08-01

    An experiment varying the racial (Black, White) and opinion composition in small-group discussions was conducted with college students (N = 357) at three universities to test for effects on the perceived novelty of group members' contributions to discussion and on participants' integrative complexity. Results showed that racial and opinion minorities were both perceived as contributing to novelty. Generally positive effects on integrative complexity were found when the groups had racial- and opinion-minority members and when members reported having racially diverse friends and classmates. The findings are discussed in the context of social psychological theories of minority influence and social policy implications for affirmative action. The research supports claims about the educational significance of race in higher education, as well as the complexity of the interaction of racial diversity with contextual and individual factors.

  16. Delayed mortality effects cut the malaria transmission potential of insecticide-resistant mosquitoes

    PubMed Central

    Viana, Mafalda; Hughes, Angela; Matthiopoulos, Jason; Ranson, Hilary; Ferguson, Heather M.

    2016-01-01

    Malaria transmission has been substantially reduced across Africa through the distribution of long-lasting insecticidal nets (LLINs). However, the emergence of insecticide resistance within mosquito vectors risks jeopardizing the future efficacy of this control strategy. The severity of this threat is uncertain because the consequences of resistance for mosquito fitness are poorly understood: while resistant mosquitoes are no longer immediately killed upon contact with LLINs, their transmission potential may be curtailed because of longer-term fitness costs that persist beyond the first 24 h after exposure. Here, we used a Bayesian state-space model to quantify the immediate (within 24 h of exposure) and delayed (>24 h after exposure) impact of insecticides on daily survival and malaria transmission potential of moderately and highly resistant laboratory populations of the major African malaria vector Anopheles gambiae. Contact with LLINs reduced the immediate survival of moderately and highly resistant An. gambiae strains by 60–100% and 3–61%, respectively, and delayed mortality impacts occurring beyond the first 24 h after exposure further reduced their overall life spans by nearly one-half. In total, insecticide exposure was predicted to reduce the lifetime malaria transmission potential of insecticide-resistant vectors by two-thirds, with delayed effects accounting for at least one-half of this reduction. The existence of substantial, previously unreported, delayed mortality effects within highly resistant malaria vectors following exposure to insecticides does not diminish the threat of growing resistance, but posits an explanation for the apparent paradox of continued LLIN effectiveness in the presence of high insecticide resistance. PMID:27402740

  17. The Effect of a Constant Time Delay Procedure on Teaching an Adult with Severe Mental Retardation a Recreation Bowling Skill

    ERIC Educational Resources Information Center

    Zhang, Jiabei; Cote, Bridget; Chen, Shihui; Liu, John

    2004-01-01

    The purpose of this study was to examine the effect of a constant time delay (CTD) procedure on teaching a recreational bowling skill to a 39-year-old male with severe mental retardation. The CTD procedure used 5 seconds as delay interval, task direction as target stimulus, physical assistance as controlling prompt, and oral praise as reinforcer.…

  18. 75 FR 78928 - Limited Service Domestic Voyage Load Lines for River Barges on Lake Michigan, Delay of Effective...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-17

    ... than 4 feet. Small Craft Advisories may also be issued when lake ice exists that could be hazardous to... Barges on Lake Michigan, Delay of Effective Date AGENCY: Coast Guard, DHS. ACTION: Notice of delay of... special load line regimes for certain river barges operating on Lake Michigan. This rule finalized interim...

  19. The Effects of Constant Time Delay and Strategic Instruction on Students with Learning Disabilities' Maintenance and Generalization

    ERIC Educational Resources Information Center

    Flores, Margaret M.; Houchins, David E.; Shippen, Margaret E.

    2006-01-01

    The purpose of this series of case studies was to compare the impact of Constant Time Delay and Strategic Instruction on the maintenance and generalization of learning. Four middle school students with learning disabilities were effectively taught two different groups of multiplication facts using Constant Time Delay and Strategic instruction. The…

  20. The Effect of a Constant Time Delay Procedure on Teaching an Adult with Severe Mental Retardation a Recreation Bowling Skill

    ERIC Educational Resources Information Center

    Zhang, Jiabei; Cote, Bridget; Chen, Shihui; Liu, John

    2004-01-01

    The purpose of this study was to examine the effect of a constant time delay (CTD) procedure on teaching a recreational bowling skill to a 39-year-old male with severe mental retardation. The CTD procedure used 5 seconds as delay interval, task direction as target stimulus, physical assistance as controlling prompt, and oral praise as reinforcer.…

  1. Effects of two antagonistic ecosystem engineers on infaunal diversity

    NASA Astrophysics Data System (ADS)

    González-Ortiz, V.; Alcazar, P.; Vergara, J. J.; Pérez-Lloréns, J. L.; Brun, F. G.

    2014-02-01

    The role of ecosystem engineers has been highlighted in recent decades because of their importance for ecosystem functioning, although the interaction between different antagonistic engineer species and their effects on ecosystems have been so far poorly investigated. Coastal areas are good natural laboratories to explore such interactions, since they are often inhabited by macrophyte beds (autogenic engineers) and bioturbator species (allogenic engineers) with antagonistic effects on ecosystem properties and processes (e.g. species diversity, nutrient fluxes, etc.). The main goal of this study was to determine how coexisting antagonistic ecosystem engineers could influence benthic diversity and available resources in soft-bottom areas. To achieve this goal, a two-month experiment was carried out in situ by introducing artificial seagrass patches in a soft-bottom area inhabited by the fiddler crab Uca tangeri. Both the experimental exclusion of burrows as well as the presence of artificial seagrass-like structures (mimics) resulted in higher macrobenthic density and species richness in the benthic community. Resource availability for organisms (sediment chlorophyll a and epiphytes) was also favoured by the presence of mimics. Therefore, the higher structural complexity (above- and below-ground) associated with seagrass mimics promoted positive effects for infauna such as creation of a new habitat ready to colonize, reduction of the crab burrowing activity and the enhancement of resource availability, which resulted in increased diversity in the benthic community.

  2. Sensitivity and uncertainty in the effective delayed neutron fraction ({beta}{sub eff})

    SciTech Connect

    Kodeli, I. I.

    2012-07-01

    Precise knowledge of effective delayed neutron fraction ({beta}{sub eff}) and of the corresponding uncertainty is important for reactor safety analysis. The interest in developing the methodology for estimating the uncertainty in {beta}{sub eff} was expressed in the scope of the UAM project of the OECD/NEA. A novel approach for the calculation of the nuclear data sensitivity and uncertainty of the effective delayed neutron fraction is proposed, based on the linear perturbation theory. The method allows the detailed analysis of components of {beta}{sub eff} uncertainty. The procedure was implemented in the SUSD3D sensitivity and uncertainty code applied to several fast neutron benchmark experiments from the ICSBEP and IRPhE databases. According to the JENDL-4 covariance matrices and taking into account the uncertainty in the cross sections and in the prompt and delayed fission spectra the total uncertainty in {beta}eff was found to be of the order of {approx}2 to {approx}3.5 % for the studied fast experiments. (authors)

  3. Design and In Vivo Anti-Inflammatory Effect of Ketoprofen Delayed Delivery Systems.

    PubMed

    Cerciello, Andrea; Auriemma, Giulia; Morello, Silvana; Pinto, Aldo; Del Gaudio, Pasquale; Russo, Paola; Aquino, Rita P

    2015-10-01

    For the treatment of inflammatory-based diseases affected by circadian rhythms, the development of once-daily dosage forms is required to target early morning symptoms. In this study, Zn-alginate beads containing ketoprofen (K) were developed by a tandem technique prilling/ionotropic gelation. The effect of main critical variables on particles micromeritics, inner structure as well as on drug loading and in vitro drug release was studied. The in vivo anti-inflammatory efficacy was evaluated using a modified protocol of carrageenan-induced edema in rat paw administering beads to rats by oral gavage at 0, 3, or 5 h before edema induction. Good drug loading and desired particle size and morphology were obtained for the optimized formulation F20. In vitro dissolution studies showed that F20 had a gastroresistant behavior and delayed release of the drug in simulated intestinal fluid. The in vitro delayed release pattern was clearly reflected in the prolonged anti-inflammatory effect in vivo of F20, compared to pure ketoprofen; F20, administered 3 h before edema induction, showed a significant anti-inflammatory activity, reducing maximum paw volume in response to carrageenan injection, whereas no response was observed for ketoprofen. The designed beads appear a promising platform suitable for a delayed release of anti-inflammatory drugs. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 104:3451-3458, 2015.

  4. Does goal relevant episodic future thinking amplify the effect on delay discounting?

    PubMed

    O'Donnell, Sara; Oluyomi Daniel, Tinuke; Epstein, Leonard H

    2017-03-07

    Delay discounting (DD) is the preference for smaller immediate rewards over larger delayed rewards. Research shows episodic future thinking (EFT), or mentally simulating future experiences, reframes the choice between small immediate and larger delayed rewards, and can reduce DD. Only general EFT has been studied, whereby people reframe decisions in terms of non-goal related future events. Since future thinking is often goal-oriented and leads to greater activation of brain regions involved in prospection, goal-oriented EFT may be associated with greater reductions in DD than general goal-unrelated EFT. The present study (n=104, Mage=22.25, SD=3.42; 50% Female) used a between-subjects 2×2 factorial design with type of episodic thinking (Goal, General) and temporal perspective (Episodic future versus recent thinking; EFT vs ERT) as between factors. Results showed a significant reduction in DD for EFT groups (p<0.001, Cohen's d effect size=0.89), and goal-EFT was more effective than general-EFT on reducing DD (p=0.03, d=0.64).

  5. The effect of aperture averaging upon tropospheric delay fluctuations seen with a DSN antenna

    NASA Technical Reports Server (NTRS)

    Linfield, R.

    1996-01-01

    The spectrum of tropospheric delay fluctuations expected for a DSN antenna at time scales less than 100 s has been calculated. A new feature included in these calculations is the effect of aperture averaging, which causes a reduction in delay fluctuations on time scales less than the antenna wind speed crossing time, approximately equal to 5-10 s. On time scales less than a few seconds, the Allan deviation sigma(sub y)(Delta(t)) varies as (Delta(t))(sup +1), rather than sigma(sub y)(Delta(t)) varies as (Delta(t))(exp -1/6) without aperture averaging. Due to thermal radiometer noise, calibration of tropospheric delay fluctuations with water vapor radiometers will not be possible on time scales less than approximately 10 s. However, the tropospheric fluctuation level will be small enough that radio science measurements with a spacecraft on time scales less than a few seconds will be limited by the stability of frequency standards and/or other nontropospheric effects.

  6. Competitive coexistence and competitive exclusion for a nonlinear community with delay effect and impulsive birth

    NASA Astrophysics Data System (ADS)

    Liu, Yanping; Zhang, Feng; Wei, Jianzhou

    2016-12-01

    By constructing a population model of multi-species competition, a community with nonlinear interaction relationship is investigated, in which the species' response delay and environmental fluctuation effects (i.e., seasonal fluctuation of resource supplies and species' reproductive activities) on population are considered. Firstly, the conditions about competitive coexistence (i.e., persistence of all species) and competitive exclusion (i.e., only partial of species, but not all, keep persistence) of the community are established, and the underlying ecological mechanism of these results are analyzed. Secondly, by some illustrative examples, the interactive effects of nonlinear competition, species' response delay and environmental fluctuation on the structure of community are explored. It is demonstrated that small response delay and slight deviation of nonlinear competition indexes from 1 have little impact on the coexistence of community, but acute changes have distinct negative influence on community coexistence. This reveals to us that parameter perturbations of natural communities should keep in an appropriate range, which is of great significance in conservation and restoration biology.

  7. Prospective memory in dynamic environments: effects of load, delay, and phonological rehearsal

    NASA Technical Reports Server (NTRS)

    Stone, M.; Dismukes, K.; Remington, R.

    2001-01-01

    A new paradigm was developed to examine prospective memory performance in a visual-spatial task that resembles some aspects of the work of air traffic controllers. Two experiments examined the role of workload (number of aeroplanes that participants directed), delay (between receipt of prospective instructions and execution), and phonological rehearsal. High workload increased prospective memory errors but increasing delay from 1-3 or 5 minutes had no effect. Shadowing aurally presented text reduced prospective memory performance, presumably because it prevented verbal rehearsal of the prospective instructions. However, performance on the foreground task of directing aeroplanes to routine destinations was affected only by workload and not by opportunity for rehearsal. Our results suggest that ability to maintain performance on a routine foreground task while performing a secondary task--perhaps analogous to conversation--does not predict ability to retrieve a prospective intention to deviate from the routine.

  8. Hopf bifurcation in a diffusive Lotka-Volterra type system with nonlocal delay effect

    NASA Astrophysics Data System (ADS)

    Guo, Shangjiang; Yan, Shuling

    2016-01-01

    The dynamics of a diffusive Lotka-Volterra type model for two species with nonlocal delay effect and Dirichlet boundary conditions is investigated in this paper. The existence and multiplicity of spatially nonhomogeneous steady-state solutions are obtained by means of Lyapunov-Schmidt reduction. The stability of spatially nonhomogeneous steady-state solutions and the existence of Hopf bifurcation with the changes of the time delay are obtained by analyzing the distribution of eigenvalues of the infinitesimal generator associated with the linearized system. By the normal form theory and the center manifold reduction, the stability and bifurcation direction of Hopf bifurcating periodic orbits are derived. Finally, our theoretical results are illustrated by a model with homogeneous kernels and one-dimensional spatial domain.

  9. Pessimum effect of externally applied chlorides on expansion due to delayed ettringite formation: Proposed mechanism

    SciTech Connect

    Ekolu, S.O. . E-mail: s.ekolu@utoronto.ca; Thomas, M.D.A.; Hooton, R.D.

    2006-04-15

    Mortars and concretes were subjected to a heat treatment cycle consisting of a pre-set period of 4 h at 23 deg. C followed by accelerated curing at 95 deg. C prior to storage at room temperature in water or limewater, 0.5 M, 2.8 M sodium chloride solutions. It was found that the specimens stored in 0.5 M sodium chloride solution gave a much greater expansion than those stored in limewater or 2.8 M sodium chloride solution. This pessimum influence of chlorides on expansion due to delayed ettringite formation deviates from the commonly held view that chlorides mitigate sulphate attack in concretes. The mechanism of the pessimum effect of chlorides on expansion due to delayed ettringite formation, and the final products of the associated phase transformations have been proposed. X-ray diffraction and differential thermal analysis techniques were used to follow phase transformations.

  10. Delayed cord clamping in red blood cell alloimmunization: safe, effective, and free?

    PubMed Central

    2016-01-01

    Hemolytic disease of the newborn (HDN), an alloimmune disorder due to maternal and fetal blood type incompatibility, is associated with fetal and neonatal complications related to red blood cell (RBC) hemolysis. After delivery, without placental clearance, neonatal hyperbilirubinemia may develop from ongoing maternal antibody-mediated RBC hemolysis. In cases refractory to intensive phototherapy treatment, exchange transfusions (ET) may be performed to prevent central nervous system damage by reducing circulating bilirubin levels and to replace antibody-coated red blood cells with antigen-negative RBCs. The risks and costs of treating HDN are significant, but appear to be decreased by delayed umbilical cord clamping at birth, a strategy that promotes placental transfusion to the newborn. Compared to immediate cord clamping (ICC), safe and beneficial short-term outcomes have been demonstrated in preterm and term neonates receiving delayed cord clamping (DCC), a practice that may potentially be effective in cases RBC alloimmunization. PMID:27186530

  11. Effects of time-delay in a model of intra- and inter-personal motor coordination

    NASA Astrophysics Data System (ADS)

    Słowiński, Piotr; Tsaneva-Atanasova, Krasimira; Krauskopf, Bernd

    2016-11-01

    Motor coordination is an important feature of intra- and inter-personal interactions, and several scenarios — from finger tapping to human-computer interfaces — have been investigated experimentally. In the 1980s, Haken, Kelso and Bunz formulated a coupled nonlinear two-oscillator model, which has been shown to describe many observed aspects of coordination tasks. We present here a bifurcation study of this model, where we consider a delay in the coupling. The delay is shown to have a significant effect on the observed dynamics. In particular, we find a much larger degree of bistablility between in-phase and anti-phase oscillations in the presence of a frequency detuning.

  12. Prospective memory in dynamic environments: effects of load, delay, and phonological rehearsal

    NASA Technical Reports Server (NTRS)

    Stone, M.; Dismukes, K.; Remington, R.

    2001-01-01

    A new paradigm was developed to examine prospective memory performance in a visual-spatial task that resembles some aspects of the work of air traffic controllers. Two experiments examined the role of workload (number of aeroplanes that participants directed), delay (between receipt of prospective instructions and execution), and phonological rehearsal. High workload increased prospective memory errors but increasing delay from 1-3 or 5 minutes had no effect. Shadowing aurally presented text reduced prospective memory performance, presumably because it prevented verbal rehearsal of the prospective instructions. However, performance on the foreground task of directing aeroplanes to routine destinations was affected only by workload and not by opportunity for rehearsal. Our results suggest that ability to maintain performance on a routine foreground task while performing a secondary task--perhaps analogous to conversation--does not predict ability to retrieve a prospective intention to deviate from the routine.

  13. Mechanisms Controlling the Plant Diversity Effect on Soil Microbial Community Composition and Soil Microbial Diversity

    NASA Astrophysics Data System (ADS)

    Mellado Vázquez, P. G.; Lange, M.; Griffiths, R.; Malik, A.; Ravenek, J.; Strecker, T.; Eisenhauer, N.; Gleixner, G.

    2015-12-01

    Soil microorganisms are the main drivers of soil organic matter cycling. Organic matter input by living plants is the major energy and matter source for soil microorganisms, higher organic matter inputs are found in highly diverse plant communities. It is therefore relevant to understand how plant diversity alters the soil microbial community and soil organic matter. In a general sense, microbial biomass and microbial diversity increase with increasing plant diversity, however the mechanisms driving these interactions are not fully explored. Working with soils from a long-term biodiversity experiment (The Jena Experiment), we investigated how changes in the soil microbial dynamics related to plant diversity were explained by biotic and abiotic factors. Microbial biomass quantification and differentiation of bacterial and fungal groups was done by phospholipid fatty acid (PLFA) analysis; terminal-restriction fragment length polymorphism was used to determine the bacterial diversity. Gram negative (G-) bacteria predominated in high plant diversity; Gram positive (G+) bacteria were more abundant in low plant diversity and saprotrophic fungi were independent from plant diversity. The separation between G- and G+ bacteria in relation to plant diversity was governed by a difference in carbon-input related factors (e.g. root biomass and soil moisture) between plant diversity levels. Moreover, the bacterial diversity increased with plant diversity and the evenness of the PLFA markers decreased. Our results showed that higher plant diversity favors carbon-input related factors and this in turn favors the development of microbial communities specialized in utilizing new carbon inputs (i.e. G- bacteria), which are contributing to the export of new C from plants to soils.

  14. Shortening baroreflex delay in hypertrophic cardiomyopathy patients – an unknown effect of β-blockers

    PubMed Central

    Katarzynska-Szymanska, Agnieszka; Ochotny, Romuald; Oko-Sarnowska, Zofia; Wachowiak-Baszynska, Hanna; Krauze, Tomasz; Piskorski, Jaroslaw; Gwizdala, Adrian; Mitkowski, Przemyslaw; Guzik, Przemyslaw

    2013-01-01

    Aims Hypertrophic cardiomyopathy (HCM) is characterized by left ventricular hypertrophy and impaired diastolic and systolic function. Abnormal sympathetic–parasympathetic balance is a potential stimulus for left ventricular hypertrophy in HCM patients. β-Blockers are routinely used in HCM for their strong negative inotropic effect; however, these drugs also influence the sympathetic–parasympathetic balance. This study aimed to determine the autonomic control of the cardiovascular system and the autonomic effects of β-blockers in HCM patients treated or untreated with β-blockers. Methods Among 51 HCM outpatients (18–70 years old; 29 men) there were 19 individuals with no medication and 32 subjects treated with a β-blocker. Fourteen age- and gender-matched (23–70 years old; nine men) healthy volunteers were enrolled in the control group. Continuous, non-invasive finger blood pressure was recorded during supine rest for 30 min. Autonomic regulation of the cardiovascular system was measured by heart rate variability and spontaneous baroreflex function (cross-correlation sequence method). Results The mean pulse interval, time domain and spectral measures of heart rate variability and baroreflex sensitivity were comparable between HCM patients, treated or not with β-blockers, and the control group. However, the delay of the baroreflex was significantly longer in HCM patients who were not treated with β-blockers [2.0 (1.6–2.3) s] in comparison with HCM patients receiving β-blockers [1.4 (1.1–1.8) s; P = 0.0072] or control subjects [1.2 (0.8–1.8) s; P = 0.0025]. This delay did not differ between HCM patients treated with β-blockers and the control group. Conclusions Hypertrophic cardiomyopathy not treated with β-blockers is accompanied by prolonged baroreflex delay. The use of β-blockers normalizes this delay. PMID:23126403

  15. Shortening baroreflex delay in hypertrophic cardiomyopathy patients -- an unknown effect of β-blockers.

    PubMed

    Katarzynska-Szymanska, Agnieszka; Ochotny, Romuald; Oko-Sarnowska, Zofia; Wachowiak-Baszynska, Hanna; Krauze, Tomasz; Piskorski, Jaroslaw; Gwizdala, Adrian; Mitkowski, Przemyslaw; Guzik, Przemyslaw

    2013-06-01

    Hypertrophic cardiomyopathy (HCM) is characterized by left ventricular hypertrophy and impaired diastolic and systolic function. Abnormal sympathetic-parasympathetic balance is a potential stimulus for left ventricular hypertrophy in HCM patients. β-Blockers are routinely used in HCM for their strong negative inotropic effect; however, these drugs also influence the sympathetic-parasympathetic balance. This study aimed to determine the autonomic control of the cardiovascular system and the autonomic effects of β-blockers in HCM patients treated or untreated with β-blockers. Among 51 HCM outpatients (18-70 years old; 29 men) there were 19 individuals with no medication and 32 subjects treated with a β-blocker. Fourteen age- and gender-matched (23-70 years old; nine men) healthy volunteers were enrolled in the control group. Continuous, non-invasive finger blood pressure was recorded during supine rest for 30 min. Autonomic regulation of the cardiovascular system was measured by heart rate variability and spontaneous baroreflex function (cross-correlation sequence method). The mean pulse interval, time domain and spectral measures of heart rate variability and baroreflex sensitivity were comparable between HCM patients, treated or not with β-blockers, and the control group. However, the delay of the baroreflex was significantly longer in HCM patients who were not treated with β-blockers [2.0 (1.6-2.3) s] in comparison with HCM patients receiving β-blockers [1.4 (1.1-1.8) s; P = 0.0072] or control subjects [1.2 (0.8-1.8) s; P = 0.0025]. This delay did not differ between HCM patients treated with β-blockers and the control group. Hypertrophic cardiomyopathy not treated with β-blockers is accompanied by prolonged baroreflex delay. The use of β-blockers normalizes this delay. © 2012 The Authors. British Journal of Clinical Pharmacology © 2012 The British Pharmacological Society.

  16. Pollen diversity matters: revealing the neglected effect of pollen diversity on fitness in fragmented landscapes.

    PubMed

    Breed, Martin F; Marklund, Maria H K; Ottewell, Kym M; Gardner, Michael G; Harris, J Berton C; Lowe, Andrew J

    2012-12-01

    Few studies have documented the impacts of habitat fragmentation on plant mating patterns together with fitness. Yet, these processes require urgent attention to better understand the impact of contemporary landscape change on biodiversity and for guiding native plant genetic resource management. We examined these relationships using the predominantly insect-pollinated Eucalyptus socialis. Progeny were collected from trees located in three increasingly disturbed landscapes in southern Australia and were planted out in common garden experiments. We show that individual mating patterns were increasingly impacted by lower conspecific density caused by habitat fragmentation. We determined that reduced pollen diversity probably has effects over and above those of inbreeding on progeny fitness. This provides an alternative mechanistic explanation for the indirect density dependence often inferred between conspecific density and offspring fitness. © 2012 Blackwell Publishing Ltd.

  17. Effects of Acute and Chronic Flunitrazepam on Delay Discounting in Pigeons

    ERIC Educational Resources Information Center

    Eppolito, Amy K.; France, Charles P.; Gerak, Lisa R.

    2011-01-01

    Delay to delivery of a reinforcer can decrease responding for that reinforcer and increase responding for smaller reinforcers that are available concurrently and delivered without delay; acute administration of drugs can alter responding for large, delayed reinforcers, although the impact of chronic treatment on delay discounting is not well…

  18. The effect of polyvinyl chloride and Fe on film growth and voltage delay in SOCl/sub 2/ electrolytes

    SciTech Connect

    Boyd, J.W.

    1987-01-01

    The LiCl film formed on lithium in LiAlCl/sub 4/-SOCl/sub 2/ was examined in a scanning electron microscope. The effects of Fe and polyvinyl chloride (PVC) on the film thickness and morphology were studied and correlated to voltage delay in batteries. The PVC additive decreases the effective film thickness, changes its crystal morphology, and improves voltage delay. Contamination with Fe increases the film thickness and increases the voltage recovery time. When PVC and Fe are present, PVC partially masks the effect of Fe contamination, decreasing the film thickness and improving voltage delay.

  19. A lattice hydrodynamic model based on delayed feedback control considering the effect of flow rate difference

    NASA Astrophysics Data System (ADS)

    Wang, Yunong; Cheng, Rongjun; Ge, Hongxia

    2017-08-01

    In this paper, a lattice hydrodynamic model is derived considering not only the effect of flow rate difference but also the delayed feedback control signal which including more comprehensive information. The control method is used to analyze the stability of the model. Furthermore, the critical condition for the linear steady traffic flow is deduced and the numerical simulation is carried out to investigate the advantage of the proposed model with and without the effect of flow rate difference and the control signal. The results are consistent with the theoretical analysis correspondingly.

  20. Best-fit estimate of relativistic effects in time-delay experiments.

    NASA Technical Reports Server (NTRS)

    Richard, J.-P.

    1972-01-01

    Time-delay experiments are analyzed within the frame of a curved space-time. Residuals from Newtonian best fits of relativistic data are used as a measure of the 'relativistic effects.' Radial transponder trajectories are considered. If the motion is towards the sun, the relativistic residuals are of the order of 100 m. If the motion is away from the sun, they are at the 10-km level and the fraction due to the second-order curvature of the metric is at the 1-km level. Those effects are significantly smaller than those calculated from the divergence of the Newtonian and relativistic predictions after exact fit of the initial measurements.

  1. Marble burying as a test of the delayed anxiogenic effects of acute immobilisation stress in mice.

    PubMed

    Kedia, Sonal; Chattarji, Sumantra

    2014-08-15

    A majority of rodent studies characterizing the anxiogenic effects of stress have utilized exploration-based models, such as the elevated plus-maze. An alternative strategy has relied on ethologically natural behavior such as defensive burying. One such paradigm, marble burying, has proven to be an effective behavioral assay of the anxiolytic effects of pharmacological manipulations, and of genetically modified mouse models. Relatively little, however, is known about the sensitivity of this test in assessing the anxiogenic effects of stress. Most of the earlier reports have examined the immediate, but not more long-term, effects of pharmacological or environmental manipulations in mice. Hence, we used the marble burying test to examine if acute immobilization stress leads to enhanced anxiety-like behavior in C57Bl/6 mice if the test is employed with a significant time delay. We find this test to be sensitive enough to detect the anxiogenic effects even 10 days after a single episode of 2-h immobilization stress. Our results suggest that the marble burying test could serve as a useful behavioral paradigm for not only estimating the gradual progression of the anxiogenic impact of stress over time, but also raises the possibility of using the temporal delay after stress to test the potential efficacy of post-stress interventions with anxiolytic drugs.

  2. Investigation of the effects of bandwidth and time delay on helicopter roll-axis handling qualities

    NASA Technical Reports Server (NTRS)

    Pausder, Heinz-Juergen; Blanken, Chris L.

    1993-01-01

    Several years of cooperative research conducted under the U.S./German Memorandum of Understanding (MOU) in helicopter flight control has recently resulted in a successful handling qualities study. The focus of this cooperative research has been the effects on handling qualities due to time delays in combination with a high bandwidth vehicle. The jointly performed study included the use of U.S. ground-based simulation and German in-flight simulation facilities. The NASA-Ames Vertical Motion Simulator (VMS) was used to develop a high bandwidth slalom tracking task which took into consideration the constraints of the facilities. The VMS was also used to define a range of the test parameters and to perform initial handling qualities evaluations. The flight tests were conducted using DLR's variable-stability BO 105 S3 Advanced Technology Testing Helicopter System (ATTHeS). Configurations included a rate command and an attitude command response system with added time delays up to 160 milliseconds over the baseline and bandwidth values between 1.5 and 4.5 rad/sec. Sixty-six evaluations were performed in about 25 hours of flight time during ten days of testing. The results indicate a need to more tightly constrain the allowable roll axis phase delay for the Level 1 and Level 2 requirements in the U.S. Army's specification for helicopter handling qualities, ADS-33C.

  3. Effect of Earth and Mars departure delays on human missions to Mars

    NASA Technical Reports Server (NTRS)

    Desai, Prasun N.; Tartabini, Paul V.

    1993-01-01

    This study determines the impact on the initial mass in low-Earth orbit (IMLEO) for delaying departure from Mars and Earth by 5, 15, and 30 days, once a nominal mission to Mars has been selected. Additionally, the use of a deep space maneuver (DSM) is attempted to alleviate the IMLEO penalties. Three different classes of missions are analyzed using chemical and nuclear thermal propulsion systems in the 2000-2025 time-frame: opposition, conjunction, and fast-transfer conjunction. The results indicate that Mars and Earth delays can lead to large IMLEO penalties. Opposition and fast-transfer conjunction class missions have the highest IMLEO penalties, upwards of 432.4 mt and 1977.3 mt, respectively. Conjunction class missions, on the other hand, tend to be insensitive to Mars and Earth delays having IMLEO penalties under 103.5 mt. As expected, nuclear thermal propulsion had significantly lower IMLEO penalties as compared to chemical propulsion. The use of a DSM is found not to have a significant impact on reducing the IMLEO penalties. Through this investigation, the effect of off-nominal departure conditions on the overall mission (i.e., IMLEO) can be gained, enabling mission designers to incorporate the influence of off-nominal departure conditions of the interplanetary trajectory in the overall conceptual design process of a Mars transfer vehicle.

  4. Effect of Nb on Delayed Fracture Resistance of Ultra-High Strength Martensitic Steels

    NASA Astrophysics Data System (ADS)

    Song, Rongjie; Fonstein, Nina; Pottore, Narayan; Jun, Hyun Jo; Bhattacharya, Debanshu; Jansto, Steve

    Ultra-high strength steels are materials of considerable interest for automotive and structural applications and are increasingly being used in those areas. Higher strength, however, makes steels more prone to hydrogen embrittlement (HE). The effects of Nb and other alloying elements on the hydrogen-induced delayed fracture resistance of cold rolled martensitic steels with ultra-high strength 2000 MPa were studied using an acid immersion test, thermal desorption analysis (TDA) and measuring of permeation. The microstructure was characterized by high resolution field emission Scanning Electron Microscopy (SEM) with Electron Backscattered Diffraction (EBSD) and Transmission Electron Microscopy (TEM). It was shown that the combined addition of Nb significantly improved the delayed fracture resistance of investigated steel. The addition of Nb to alloyed martensitic steels resulted in very apparent grain refinement of the prior austenite grain size. The Nb microalloyed steel contained a lower diffusible hydrogen content during thermal desorption analysis as compared to the base steel and had a higher trapped hydrogen amount after charging. The reason that Nb improved the delayed fracture resistance of steels can be attributed mostly to both hydrogen trapping and grain refinement.

  5. Protective effect of Cissus quadrangularis Linn. on diabetes induced delayed fetal skeletal ossification.

    PubMed

    Sirasanagandla, Srinivasa Rao; Ranganath Pai, K Sreedhara; Potu, Bhagath Kumar; Bhat, Kumar Mr

    2014-01-01

    Delayed fetal skeletal ossification is one of the known complications of maternal diabetes. The present study was designed to evaluate the protective role of petroleum ether extract of Cissus quadrangularis (PECQ) on diabetes-induced delayed fetal skeletal ossification. Female Wistar rats were rendered diabetic with streptozotocin (STZ, 40 mg/kg, intraperitonial) before mating. After confirmation of pregnancy, the pregnant rats were divided into three groups: normal control group, diabetic control group, and diabetic + CQ group. The diabetic + CQ group pregnant rats were treated with PECQ (500 mg/kg body weight) throughout their gestation period. Immediately after delivery, pups were collected from all three groups and processed for alizarin red S-alcian blue staining in order to examine the pattern of skeletal ossification. Fewer ossification centers and decreased extent of ossification of forelimb and hindlimb bones were observed in the neonatal pups of diabetic control group as compared to those in the normal control group. PECQ pretreatment significantly restored the ossification centers and improved the extent of ossification of forelimb and hindlimb bones in the neonatal pups of diabetic + CQ group as compared to those in the diabetic control group. The results suggested that PECQ treatment is effective against diabetes-induced delayed fetal skeletal ossification. However, further studies on the isolation and characterization of active constituents of PECQ, which can cross the placental barrier and are responsible for the bone anabolic activity are warranted.

  6. Effectiveness of sulfur-containing antioxidants in delaying skeletal muscle fatigue.

    PubMed

    Ferreira, Leonardo F; Campbell, Kenneth S; Reid, Michael B

    2011-06-01

    Reactions involving thiol biochemistry seem to play a crucial role in skeletal muscle fatigue. N-acetylcysteine amide (NACA) and L-ergothioneine (ERGO) are thiol-based antioxidants available for human use that have not been evaluated for effects on muscle fatigue. To test the hypothesis that NACA and ERGO delay skeletal muscle fatigue. We exposed mouse diaphragm fiber bundles to buffer (CTRL), NACA, ERGO, or N-acetylcysteine (NAC; positive control). Treatments were performed in vitro using 10 mM for 60 min at 37 °C. After treatment, we determined the muscle force-frequency and fatigue characteristics. The force-frequency relationship was shifted to the left by ERGO and to the right by NACA compared with CTRL and NAC. Maximal tetanic force was similar among groups. The total force-time integral (FTI; N · s · cm) during the fatigue trial was decreased by NACA (420 ± 35, P < 0.05), unaffected by ERGO (657 ± 53), and increased by NAC (P < 0.05) compared with CTRL (581 ± 54). The rate of contraction (dF/dtMAX) during the fatigue trial was not affected by any of the treatments tested. NAC, but not NACA or ERGO, delayed the slowing of muscle relaxation (dF/dtMIN) during fatigue. In summary, NACA and ERGO did not delay skeletal muscle fatigue in vitro. We conclude that these antioxidants are unlikely to improve human exercise performance.

  7. Effect of Earth and Mars departure delays on human missions to Mars

    NASA Astrophysics Data System (ADS)

    Desai, Prasun N.; Tartabini, Paul V.

    1993-08-01

    This study determines the impact on the initial mass in low-Earth orbit (IMLEO) for delaying departure from Mars and Earth by 5, 15, and 30 days, once a nominal mission to Mars has been selected. Additionally, the use of a deep space maneuver (DSM) is attempted to alleviate the IMLEO penalties. Three different classes of missions are analyzed using chemical and nuclear thermal propulsion systems in the 2000-2025 time-frame: opposition, conjunction, and fast-transfer conjunction. The results indicate that Mars and Earth delays can lead to large IMLEO penalties. Opposition and fast-transfer conjunction class missions have the highest IMLEO penalties, upwards of 432.4 mt and 1977.3 mt, respectively. Conjunction class missions, on the other hand, tend to be insensitive to Mars and Earth delays having IMLEO penalties under 103.5 mt. As expected, nuclear thermal propulsion had significantly lower IMLEO penalties as compared to chemical propulsion. The use of a DSM is found not to have a significant impact on reducing the IMLEO penalties. Through this investigation, the effect of off-nominal departure conditions on the overall mission (i.e., IMLEO) can be gained, enabling mission designers to incorporate the influence of off-nominal departure conditions of the interplanetary trajectory in the overall conceptual design process of a Mars transfer vehicle.

  8. Effects of early and delayed visual experience on intersensory development in bobwhite quail chicks.

    PubMed

    Banker, H; Lickliter, R

    1993-04-01

    The relative impact of early versus delayed visual experience on intersensory development was studied by manipulating the timing of visual experience of bobwhite quail (Colinus virginianus) embryos and hatchlings. Previous studies with quail chicks have revealed that: (1) Socially reared chicks require only maternal auditory cues to direct their social preferences in the first 2 days following hatching; (2) by 3 days following hatching chicks require both auditory and visual maternal cues to direct their social preferences; (3) chicks which have received unusually early visual experience as embryos require both auditory and visual cues by 24 hr following hatching, indicating an accelerated pattern of the emergence of intersensory functioning; and (4) chicks reared under conditions of attenuated social and visual experience continue to rely on maternal auditory cues alone at 4 days following hatching, indicating a decelerated pattern of early intersensory functioning. In the present study, quail chicks that received both early visual experience as embryos and delayed visual experience as hatchlings exhibited a pattern of both auditory and visual responsiveness like that seen in normally reared chicks. These results indicate that, at least under the present experimental conditions, the influence of early and delayed visual experience on perinatal perceptual development appears to be relatively comparable in effect.

  9. Effect of Earth and Mars departure delays on human missions to Mars

    NASA Technical Reports Server (NTRS)

    Desai, Prasun N.; Tartabini, Paul V.

    1993-01-01

    This study determines the impact on the initial mass in low-Earth orbit (IMLEO) for delaying departure from Mars and Earth by 5, 15, and 30 days, once a nominal mission to Mars has been selected. Additionally, the use of a deep space maneuver (DSM) is attempted to alleviate the IMLEO penalties. Three different classes of missions are analyzed using chemical and nuclear thermal propulsion systems in the 2000-2025 time-frame: opposition, conjunction, and fast-transfer conjunction. The results indicate that Mars and Earth delays can lead to large IMLEO penalties. Opposition and fast-transfer conjunction class missions have the highest IMLEO penalties, upwards of 432.4 mt and 1977.3 mt, respectively. Conjunction class missions, on the other hand, tend to be insensitive to Mars and Earth delays having IMLEO penalties under 103.5 mt. As expected, nuclear thermal propulsion had significantly lower IMLEO penalties as compared to chemical propulsion. The use of a DSM is found not to have a significant impact on reducing the IMLEO penalties. Through this investigation, the effect of off-nominal departure conditions on the overall mission (i.e., IMLEO) can be gained, enabling mission designers to incorporate the influence of off-nominal departure conditions of the interplanetary trajectory in the overall conceptual design process of a Mars transfer vehicle.

  10. Protective effect of Cissus quadrangularis Linn. on diabetes induced delayed fetal skeletal ossification

    PubMed Central

    Sirasanagandla, Srinivasa Rao; Ranganath Pai, K. Sreedhara; Potu, Bhagath Kumar; Bhat, Kumar MR

    2014-01-01

    Background: Delayed fetal skeletal ossification is one of the known complications of maternal diabetes. Objective: The present study was designed to evaluate the protective role of petroleum ether extract of Cissus quadrangularis (PECQ) on diabetes-induced delayed fetal skeletal ossification. Materials and Methods: Female Wistar rats were rendered diabetic with streptozotocin (STZ, 40 mg/kg, intraperitonial) before mating. After confirmation of pregnancy, the pregnant rats were divided into three groups: normal control group, diabetic control group, and diabetic + CQ group. The diabetic + CQ group pregnant rats were treated with PECQ (500 mg/kg body weight) throughout their gestation period. Immediately after delivery, pups were collected from all three groups and processed for alizarin red S–alcian blue staining in order to examine the pattern of skeletal ossification. Results: Fewer ossification centers and decreased extent of ossification of forelimb and hindlimb bones were observed in the neonatal pups of diabetic control group as compared to those in the normal control group. PECQ pretreatment significantly restored the ossification centers and improved the extent of ossification of forelimb and hindlimb bones in the neonatal pups of diabetic + CQ group as compared to those in the diabetic control group. Conclusions: The results suggested that PECQ treatment is effective against diabetes-induced delayed fetal skeletal ossification. However, further studies on the isolation and characterization of active constituents of PECQ, which can cross the placental barrier and are responsible for the bone anabolic activity are warranted. PMID:24812472

  11. Effect of Algae-Derived Biodiesel on Ignition Delay, Combustion Process and Emission

    NASA Astrophysics Data System (ADS)

    Kumaran, Mahendran; Khalid, Amir; Salleh, Hamidon; Razali, Azahari; Sapit, Azwan; Jaat, Norrizam; Sunar, Norshuhaila

    2016-11-01

    Algae oil methyl esters produced from algae oil were blended with diesel at various volumetric percentages to evaluate the variations in the fuel properties. Microalgae biodiesel production has received much interest in an effort for sustainable development as the microalgae seem to be an attractive way to produce the biodiesel due to their ability to accumulate lipids and their very high actual photosynthetic yields. Correlations between fuel properties, including the calorific heat, density, kinematic viscosity, and oxidation stability of the Algae oil-diesel blends, and the blending ratio of the algae biodiesel have been established. As a result, low blending ratio of the Algae oil with diesel was recommended up to 2vol % in comparison with other type of biodiesel-diesel blends. The objective of this research is to investigate effect of biodiesel blending ratio on ignition delay, combustion process and emission for different type of biodiesel. The combustion tests of the Algae-Derived biodiesel blends were performed in a Rapid Compression Machine (RCM). The combustion tests were carried out at injection pressure of 130 MPa and ambient temperature were varied between 750 K and 1100 K. The result from the experiment is compared with Palm-Oil biodiesel which are varied in biodiesel percentage from 5vol% to 15vol% and jatropha biodiesel. Higher ignition delay period were clearly observed with higher blending ratio. It seems that increasing blending ratio exhibits relatively weakens in fuel ignitibility and therefore prolongs the ignition delay of algae biodiesel. A2 had the lowest ignition delay period when compared with J2, B5, B10 and B15 due to lower density that present in A2 molecules.The concentration of carbon dioxide and nitrogen monoxide in the exhaust gas increased with higher blending ratio while the concentration of carbon monoxide and hydrocarbon decreased.

  12. The effect of delayed transportation of blood samples on serum bilirubin values in neonates.

    PubMed

    Saththasivam, Poovendran; Voralu, Kirtanaa; Ramli, Noraida; Mustapha, Mohd Rafi; Omar, Julia; Van Rostenberghe, Hans

    2010-07-01

    Delays in transporting blood samples may cause inaccurate results. Samples may be exposed to light or heat during delays, resulting in the degradation of analytes, for example, bilirubin. This study was done to determine the effect of delays in the transportation of blood samples on serum bilirubin test results. Samples taken from neonates admitted to a tertiary hospital with jaundice were included in the study. The samples were collected through venipuncture in 3 labelled containers. The first container was sent immediately to the laboratory, while the second and third containers were sent after being kept in the ward for 1 and 3 hours, respectively. Bilirubin values were measured colourimetrically at a wavelength of 578 nm using a Roche Hitachi 912 Chemistry Analyser upon arrival in the laboratory. A total of 36 serum samples were studied. The mean of the indirect bilirubin measurements for 0-, 1-, and 3-hour samples were 174 (SD 68.65), 186.97 (SD 60.47), and 184.56 (SD 66.93), respectively. There was a significant difference in the mean indirect bilirubin measurement of 1-hour samples (P = 0.047, 95% CI -24.66 to -1.18) and 3-hour samples (P = 0.045, 95% CI -19.77 to -0.23) compared with 0-hour samples. There were no significant differences observed in either the mean total bilirubin or the mean direct bilirubin measurements of different time intervals. This study confirms that delays in the transportation of blood samples influence the bilirubin test results.

  13. Effect of educational television commercial on pre-hospital delay in patients with ischemic stroke.

    PubMed

    Nishijima, Haruo; Kon, Tomoya; Ueno, Tatsuya; Haga, Rie; Yamazaki, Keishi; Yagihashi, Kei; Funamizu, Yukihisa; Arai, Akira; Suzuki, Chieko; Nunomura, Jin-ichi; Baba, Masayuki; Tomiyama, Masahiko

    2016-01-01

    Administering intravenous recombinant tissue plasminogen activator (r-tPA) within 4.5 h or endovascular procedures within 8 h of ischemic stroke onset may reduce the risk of disability. The effectiveness of media campaigns to raise stroke awareness and shorten pre-hospital delay is unclear. We studied 1144 consecutive ischemic stroke patients at Aomori Prefectural Central Hospital, Japan, between March 2010 and February 2014. From March 2012, the government sponsored an educational campaign based on a television commercial to improve knowledge of stroke symptoms and encourage ambulance calls for facial palsy, arm palsy, or speech disturbance. For the 544 and 600 patients admitted before and during the intervention, respectively, we recorded the National Institutes of Health Stroke Scale score, stroke type, the time when patients or bystanders recognized stroke symptoms, and hospital arrival time. Pre-hospital delay, as the time interval from awareness of stroke to hospital arrival, was categorized as 0-3, 3-6, and 6+ h. The mean pre-hospital delay was shorter (12.0 vs 13.5 h; P = 0.0067), the proportion of patients arriving within 3 h was larger (55.7 vs 46.5 %; P = 0.0021), and the proportion arriving after 6 h was smaller (32.7 vs 39.5 %; P = 0.0162) in the intervention group than in the pre-intervention group. There was no significant difference in the proportion of patients treated with r-tPA (6 and 7.5 % of the intervention and pre-intervention groups, respectively). A television-based public education campaign potentially reduced pre-hospital delay for ischemic stroke patients, but the r-tPA treatment rate was unchanged.

  14. Effects of early versus delayed excision and grafting on the return of the burned hand function.

    PubMed

    Salehi, Seyed Hamid; Fatemi, Mohammad Javad; Sedghi, Maryam; Niazi, Mitra

    2016-01-01

    Despite a general consensus regarding the impacts of early excision and grafting (EE and G) of burned hand on the reducing of treatment cost and hospital stay, there are some controversial issues about its effect on the outcome of hand function. This study conducted to compare the results of the EE and G and delayed skin grafting in deep hand burns regarding the hand functional outcome. This study was conducted from April 2012 to November 2013 in sixty patients with deep thermal burns of the dorsal hand with total body surface area (TBSA) <20% who were admitted to special burn hospital. After standard primary burn care and resuscitation, necessary procedures (EE and G or more conservative treatment) were performed based on the patients' conditions. The patients were placed into early excision (No. =30) and delayed excision group (No. =30). Total active motion (TAM) of fingers, grip strength of the hand and the assessment of disabilities of the arm, shoulder and hand questionnaire, were measured in all patients 6 months after grafting. The average percentage of TBSA in the EE and G group was more than the delayed excision group (17.34% ±5.12% vs. 15.64% ±5.83%), this difference was not significant (P = 0.23). After 6 months, the average of the TAM and grip strength in the EE and G group was significantly more than that of the delayed group (P < 0.0001 and P = 0.019). The present study showed that EE and G with proper physical therapy and rehabilitation management provides a higher functional outcome in dorsal deep burned hand.

  15. Effects of early versus delayed excision and grafting on the return of the burned hand function

    PubMed Central

    Salehi, Seyed Hamid; Fatemi, Mohammad Javad; Sedghi, Maryam; Niazi, Mitra

    2016-01-01

    Background: Despite a general consensus regarding the impacts of early excision and grafting (EE and G) of burned hand on the reducing of treatment cost and hospital stay, there are some controversial issues about its effect on the outcome of hand function. This study conducted to compare the results of the EE and G and delayed skin grafting in deep hand burns regarding the hand functional outcome. Materials and Methods: This study was conducted from April 2012 to November 2013 in sixty patients with deep thermal burns of the dorsal hand with total body surface area (TBSA) <20% who were admitted to special burn hospital. After standard primary burn care and resuscitation, necessary procedures (EE and G or more conservative treatment) were performed based on the patients’ conditions. The patients were placed into early excision (No. =30) and delayed excision group (No. =30). Total active motion (TAM) of fingers, grip strength of the hand and the assessment of disabilities of the arm, shoulder and hand questionnaire, were measured in all patients 6 months after grafting. Results: The average percentage of TBSA in the EE and G group was more than the delayed excision group (17.34% ±5.12% vs. 15.64% ±5.83%), this difference was not significant (P = 0.23). After 6 months, the average of the TAM and grip strength in the EE and G group was significantly more than that of the delayed group (P < 0.0001 and P = 0.019). Conclusion: The present study showed that EE and G with proper physical therapy and rehabilitation management provides a higher functional outcome in dorsal deep burned hand. PMID:28250786

  16. Effects of development and delayed feed access on ghrelin expression in neonatal broiler chickens.

    PubMed

    Yu, Y; Zhang, Y H; Zhang, H H; Tao, H; Ou, C B; Wang, Q X; Guo, F; Ma, J Y

    2016-10-01

    Two experiments were conducted to study the effects of development and delayed feed access on ghrelin expression in neonatal chickens. In experiment 1, ghrelin levels in ad libitum-fed chickens were assessed from hatching (0 h) to 120 h. Ghrelin mRNA expression increased after hatching and reached peak levels at 24 h; levels were 1.8-fold higher compared to those at 0 h. Afterward, ghrelin expression decreased consistently throughout the later experimental period, and at 120 h, it was only 16.0% of 0 h levels. The density of ghrelin immunopositive cells in the proventriculus and plasma ghrelin levels decreased slightly from hatching to 48 h and later increased slowly until the end of the experimental period. In a follow-up study, chickens were assigned randomly into 2 groups after hatching, a control group ( C: , fed ad libitum) and a delayed feeding group ( F+SF: , 72-h fast period, subsequently fed ad libitum). Delayed feed access for 72 h up-regulated ghrelin mRNA expression significantly in the proventriculus (P < 0.05) to 2.1-fold higher levels compared to the control, while the density of ghrelin immunopositive cells and the plasma ghrelin level decreased (P < 0.05) to 28.4% and 64.8% of the control, respectively. After the onset of feeding, the ghrelin mRNA expression in the delayed feeding group was decreased but still higher than that of the control (P < 0.05). The density of ghrelin immunopositive cells and the plasma ghrelin level climbed quickly and all returned to the control level with a supply of food for 48 h. These results suggest that the onset of feeding in neonatal chickens stimulated an increase in ghrelin peptide levels and that ghrelin peptide levels increased with age. Neonatal chickens respond to food deprivation in a different way than do young and adult chickens. © 2016 Poultry Science Association Inc.

  17. Laparoscopy mitigates adverse oncological effects of delayed adjuvant chemotherapy for colon cancer.

    PubMed

    Gantt, Gerald A; Ashburn, Jean; Kiran, Ravi P; Khorana, Alok A; Kalady, Matthew F

    2015-02-01

    Delaying initiation of adjuvant chemotherapy more than 8 weeks after surgical resection for colorectal cancer adversely affects overall patient survival. The effect of a laparoscopic surgical approach on initiation of chemotherapy has not been studied. The goal of this study was to determine if a laparoscopic approach to colon cancer resection affects the timing of adjuvant chemotherapy and outcomes. Patients who underwent curative surgery for stage II or III colon cancer and received adjuvant chemotherapy between 2003 and 2010 were identified from a prospectively maintained database. Patients were categorized according to surgical approach: open or laparoscopic. Patient demographics, clinicopathologic variables, postoperative complications, time from surgery to initiation of chemotherapy, and long-term oncologic outcomes were compared. Age, gender, ASA class, BMI, tumor stage, and postoperative complications were similar for laparoscopic and open cases, while length of stay was 2 days shorter for laparoscopic cases (5.4 vs 7.6 days, p < 0.01). The proportion of patients who received adjuvant chemotherapy more than 8 weeks after surgery did not differ between the groups (35.6 % open vs 38.7 % laparoscopic, p = 0.77). In the open group, delay in chemotherapy after surgery was associated with decreased disease-free and overall survival (p = 0.01, 0.01, respectively). However, delay in chemotherapy more than 8 weeks did not affect disease-free or overall survival in the laparoscopy group (p = 0.93, 0.51, respectively). The benefits of quicker recovery after laparoscopic surgery did not translate into earlier initiation of adjuvant chemotherapy in this retrospective study. However, a laparoscopic approach negated the inferior oncologic outcomes of patients who received delayed initiation of chemotherapy.

  18. Small scale in-rock precompression testing: Effects of delay timing

    SciTech Connect

    Mullay, J.J.; McGinley, C.J.; Anderson, G.W.; Keefer, C.J.; VanNorman, J.F.

    1994-12-31

    Previous work has shown that testing of precompression effects conducted on a small scale under simulated field conditions in actual rock provides a reasonable model for the evaluation of explosives and initiators under the adverse conditions encountered in production blasting. Using this methodology can result in greater understanding of the phenomena as well as the ability to predict performance. This effort has been extended to evaluate various parameters not previously studied in a controlled fashion. The present paper describes the use of this technique to study the effects of delay timing on precompression effects. Intervals from 25 to 150 milliseconds are included in the study. Both VOD measurements and damage estimates are utilized in the evaluation. The results demonstrate that timing delay between holes is quite important in determining the overall effectiveness of a blasting program. In addition, a parallel study was conducted to evaluate the usefulness of a smaller laboratory scale testing regime in screening various approaches to reduce the effects of precompression. Results are presented which indicate the presence of definite correlations between the laboratory procedure and the rock tests. The use of both methods together is shown to provide the explosive formulator as well as the mining engineer with an important tool for obtaining improved results.

  19. Single-gene speciation with pleiotropy: effects of allele dominance, population size, and delayed inheritance.

    PubMed

    Yamamichi, Masato; Sasaki, Akira

    2013-07-01

    Single-gene speciation is considered to be unlikely, but an excellent example is found in land snails, in which a gene for left-right reversal has given rise to new species multiple times. This reversal might be facilitated by their small population sizes and maternal effect (i.e., "delayed inheritance," in which an individual's phenotype is determined by the genotype of its mother). Recent evidence suggests that a pleiotropic effect of the speciation gene on antipredator survival may also promote speciation. Here we theoretically demonstrate that, without a pleiotropic effect, in small populations the fixation probability of a recessive mutant is higher than a dominant mutant, but they are identical for large populations and sufficiently weak selection. With a pleiotropic effect that increases mutant viability, a dominant mutant has a higher fixation probability if the strength of viability selection is sufficiently greater than that of reproductive incompatibility, whereas a recessive mutant has a higher fixation probability otherwise. Delayed inheritance increases the fixation probability of a mutant if viability selection is sufficiently weaker than reproductive incompatibility. Our results clarify the conflicting effects of viability selection and positive frequency-dependent selection due to reproductive incompatibility and provide a new perspective to single-gene speciation theory.

  20. The effect of chromosome geometry on genetic diversity.

    PubMed

    Marri, Pradeep Reddy; Harris, Leigh K; Houmiel, Kathryn; Slater, Steven C; Ochman, Howard

    2008-05-01

    Although organisms with linear chromosomes must solve the problem of fully replicating their chromosome ends, this chromosome configuration has emerged repeatedly during bacterial evolution and is evident in three divergent bacterial phyla. The benefit usually ascribed to this topology is the ability to boost genetic variation through increased recombination. But because numerous processes can impact linkage disequilibrium, such an effect is difficult to assess by comparing across bacterial taxa that possess different chromosome topologies. To test directly the contribution of chromosome architecture to genetic diversity and recombination, we examined sequence variation in strains of Agrobacterium Biovar 1, which are unique among sequenced bacteria in having both a circular and a linear chromosome. Whereas the allelic diversity among strains is generated principally by mutations, intragenic recombination is higher within genes situated on the circular chromosome. In contrast, recombination between genes is, on average, higher on the linear chromosome, but it occurs at the same rate as that observed between genes mapping to the distal portion of the circular chromosome. Collectively, our findings indicate that chromosome topology does not contribute significantly to either allelic or genotypic diversity and that the evolution of linear chromosomes is not based on a facility to recombine.

  1. Predator diversity, intraguild predation, and indirect effects drive parasite transmission

    PubMed Central

    Rohr, Jason R.; Civitello, David J.; Crumrine, Patrick W.; Halstead, Neal T.; Miller, Andrew D.; Schotthoefer, Anna M.; Stenoien, Carl; Johnson, Lucinda B.; Beasley, Val R.

    2015-01-01

    Humans are altering biodiversity globally and infectious diseases are on the rise; thus, there is interest in understanding how changes to biodiversity affect disease. Here, we explore how predator diversity shapes parasite transmission. In a mesocosm experiment that manipulated predator (larval dragonflies and damselflies) density and diversity, non-intraguild (non-IG) predators that only consume free-living cercariae (parasitic trematodes) reduced metacercarial infections in tadpoles, whereas intraguild (IG) predators that consume both parasites and tadpole hosts did not. This likely occurred because IG predators reduced tadpole densities and anticercarial behaviors, increasing per capita exposure rates of the surviving tadpoles (i.e., via density- and trait-mediated effects) despite the consumption of parasites. A mathematical model demonstrated that non-IG predators reduce macroparasite infections, but IG predation weakens this “dilution effect” and can even amplify parasite burdens. Consistent with the experiment and model, a wetland survey revealed that the diversity of IG predators was unrelated to metacercarial burdens in amphibians, but the diversity of non-IG predators was negatively correlated with infections. These results are strikingly similar to generalities that have emerged from the predator diversity–pest biocontrol literature, suggesting that there may be general mechanisms for pest control and that biocontrol research might inform disease management and vice versa. In summary, we identified a general trait of predators—where they fall on an IG predation continuum—that predicts their ability to reduce infections and possibly pests in general. Consequently, managing assemblages of predators represents an underused tool for the management of human and wildlife diseases and pest populations. PMID:25713379

  2. Delayed ejaculation

    MedlinePlus

    Ejaculatory incompetence; Sex - delayed ejaculation; Retarded ejaculation; Anejaculation; Infertility - delayed ejaculation ... include: Religious background that makes the person view sex as sinful Lack of attraction for a partner ...

  3. Telerobotic Surgery: An Intelligent Systems Approach to Mitigate the Adverse Effects of Communication Delay. Chapter 4

    NASA Technical Reports Server (NTRS)

    Cardullo, Frank M.; Lewis, Harold W., III; Panfilov, Peter B.

    2007-01-01

    An extremely innovative approach has been presented, which is to have the surgeon operate through a simulator running in real-time enhanced with an intelligent controller component to enhance the safety and efficiency of a remotely conducted operation. The use of a simulator enables the surgeon to operate in a virtual environment free from the impediments of telecommunication delay. The simulator functions as a predictor and periodically the simulator state is corrected with truth data. Three major research areas must be explored in order to ensure achieving the objectives. They are: simulator as predictor, image processing, and intelligent control. Each is equally necessary for success of the project and each of these involves a significant intelligent component in it. These are diverse, interdisciplinary areas of investigation, thereby requiring a highly coordinated effort by all the members of our team, to ensure an integrated system. The following is a brief discussion of those areas. Simulator as a predictor: The delays encountered in remote robotic surgery will be greater than any encountered in human-machine systems analysis, with the possible exception of remote operations in space. Therefore, novel compensation techniques will be developed. Included will be the development of the real-time simulator, which is at the heart of our approach. The simulator will present real-time, stereoscopic images and artificial haptic stimuli to the surgeon. Image processing: Because of the delay and the possibility of insufficient bandwidth a high level of novel image processing is necessary. This image processing will include several innovative aspects, including image interpretation, video to graphical conversion, texture extraction, geometric processing, image compression and image generation at the surgeon station. Intelligent control: Since the approach we propose is in a sense predictor based, albeit a very sophisticated predictor, a controller, which not only

  4. Simulator study of the effect of visual-motion time delays on pilot tracking performance with an audio side task

    NASA Technical Reports Server (NTRS)

    Riley, D. R.; Miller, G. K., Jr.

    1978-01-01

    The effect of time delay was determined in the visual and motion cues in a flight simulator on pilot performance in tracking a target aircraft that was oscillating sinusoidally in altitude only. An audio side task was used to assure the subject was fully occupied at all times. The results indicate that, within the test grid employed, about the same acceptable time delay (250 msec) was obtained for a single aircraft (fighter type) by each of two subjects for both fixed-base and motion-base conditions. Acceptable time delay is defined as the largest amount of delay that can be inserted simultaneously into the visual and motion cues before performance degradation occurs. A statistical analysis of the data was made to establish this value of time delay. Audio side task provided quantitative data that documented the subject's work level.

  5. Age-of-acquisition effects in delayed picture-naming tasks.

    PubMed

    Navarrete, Eduardo; Scaltritti, Michele; Mulatti, Claudio; Peressotti, Francesca

    2013-02-01

    We report two experiments that explored the linguistic locus of age-of-acquisition effects in picture naming by using a delayed naming task that involved only a low proportion of trials (25 %) while, for the large majority of the trials (75 %), participants performed another task-that is, the prevalent task. The prevalent tasks were semantic categorization in Experiment 1a and grammatical-gender decision in Experiments 1b and 2. In Experiment 1a, in which participants were biased to retrieve semantic information in order to perform the semantic categorization task, delayed naming times were affected by age of acquisition, reflecting a postsemantic locus of the effect. In Experiments 1b and 2, in which participants were biased to retrieve lexical information in order to perform the grammatical gender decision task, there was also an age-of-acquisition effect. These results suggest that part of the age-of-acquisition effect in picture naming occurs at the level at which the phonological properties of words are retrieved.

  6. Delayed effects of chlorpyrifos across metamorphosis on dispersal-related traits in a poleward moving damselfly.

    PubMed

    Dinh, Khuong Van; Janssens, Lizanne; Therry, Lieven; Bervoets, Lieven; Bonte, Dries; Stoks, Robby

    2016-11-01

    How exposure to contaminants may interfere with the widespread poleward range expansions under global warming is largely unknown. Pesticide exposure may negatively affect traits shaping the speed of range expansion, including traits related to population growth rate and dispersal-related traits. Moreover, rapid evolution of growth rates during poleward range expansions may come at a cost of a reduced investment in detoxification and repair thereby increasing the vulnerability to contaminants at expanding range fronts. We tested effects of a sublethal concentration of the widespread pesticide chlorpyrifos on traits related to range expansion in replicated edge and core populations of the poleward moving damselfly Coenagrion scitulum reared at low and high food levels in a common garden experiment. Food limitation in the larval stage had strong negative effects both in the larval stage and across metamorphosis in the adult stage. Exposure to chlorpyrifos during the larval stage did not affect larval traits but caused delayed effects across metamorphosis by increasing the incidence of wing malformations during metamorphosis and by reducing a key component of the adult immune response. There was some support for an evolutionary trade-off scenario as the faster growing edge larvae suffered a higher mortality during metamorphosis. Instead, there was no clear support for the faster growing edge larvae being more vulnerable to chlorpyrifos. Our data indicate that sublethal delayed effects of pesticide exposure, partly in association with the rapid evolution of faster growth rates, may slow down range expansions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Effects of delayed NSAID administration after experimental eccentric contraction injury – A cellular and proteomics study

    PubMed Central

    Aldape, Michael J.; Bayer, Clifford R.; Katahira, Eva J.; Bond, Laura; Nicora, Carrie D.; Fillmore, Thomas L.; Clauss, Therese R. W.; Metz, Thomas O.; Webb-Robertson, Bobbie-Jo; Stevens, Dennis L.

    2017-01-01

    Background Acute muscle injuries are exceedingly common and non-steroidal anti-inflammatory drugs (NSAIDs) are widely consumed to reduce the associated inflammation, swelling and pain that peak 1–2 days post-injury. While prophylactic use or early administration of NSAIDs has been shown to delay muscle regeneration and contribute to loss of muscle strength after healing, little is known about the effects of delayed NSAID use. Further, NSAID use following non-penetrating injury has been associated with increased risk and severity of infection, including that due to group A streptococcus, though the mechanisms remain to be elucidated. The present study investigated the effects of delayed NSAID administration on muscle repair and sought mechanisms supporting an injury/NSAID/infection axis. Methods A murine model of eccentric contraction (EC)-induced injury of the tibialis anterior muscle was used to profile the cellular and molecular changes induced by ketorolac tromethamine administered 47 hr post injury. Results NSAID administration inhibited several important muscle regeneration processes and down-regulated multiple cytoprotective proteins known to inhibit the intrinsic pathway of programmed cell death. These activities were associated with increased caspase activity in injured muscles but were independent of any NSAID effect on macrophage influx or phenotype switching. Conclusions These findings provide new molecular evidence supporting the notion that NSAIDs have a direct negative influence on muscle repair after acute strain injury in mice and thus add to renewed concern about the safety and benefits of NSAIDS in both children and adults, in those with progressive loss of muscle mass such as the elderly or patients with cancer or AIDS, and those at risk of secondary infection after trauma or surgery. PMID:28245256

  8. Radiation-induced genomic instability: delayed mutagenic and cytogenetic effects of X rays and alpha particles.

    PubMed

    Little, J B; Nagasawa, H; Pfenning, T; Vetrovs, H

    1997-10-01

    clones showing a high frequency of delayed mutations there may be a subpopulation of cells that are particularly unstable; selection for the slow-growth phenotype has the effect of selecting for this chromosomally unstable subpopulation.

  9. Line Emission in Active Galactic Nuclei: Effects of Local Delays upon Line Variability

    NASA Astrophysics Data System (ADS)

    Taylor, Jason A.

    1996-10-01

    than it actually is. These effects are similar to those that beaming can cause. Local delays can also be a source of asymmetry about the peak of the cross-correlation function.

  10. The Effect of Immediate versus Delayed Dowel Space Preparation on Endodontically Filled Teeth.

    DTIC Science & Technology

    1981-01-01

    stored. Two weeks later, twenty more weo~ similarly filled. Using hot endodontic pluggers, dowel spaces were prepare d 4h-th~t eithe 3mm or 71T11 of...Preparation on Endodontically Filled Teeth Acce sion r NTIS .... D TTC TAB Distrilu Av r i 0ou- Dist 1 A! The Effect of Immediate Versus Delayed Dowel...Space Preparation on Endodontically Filled Teeth Frank R. Portell, B.S., D.M.D., M.S. William E. Bernier, D.D.S., M.A. Lewis Lorton, D.D.S., M.S.D

  11. Effects of reward on delayed reaction time task performance of hyperactive children.

    PubMed

    Douglas, V I; Parry, P A

    1983-06-01

    This experiment was designed to investigate the effects of continuous, partial, and noncontingent schedules of reward, as well as the withdrawal of rewards, on the performance of hyperactive and normal control children on a delayed reaction time task. Although noncontingent reward resulted in faster reaction times for control subjects, performance of hyperactives deteriorated under noncontingent reward and improved when it was withdrawn. Also, reaction times of controls during extinction remained superior to baseline, whereas performance of hyperactives returned to baseline level. It was suggested that these and other findings reviewed point to an unusual sensitivity to rewards in hyperactive children.

  12. The effects of impulsive harvest on a predator-prey system with distributed time delay

    NASA Astrophysics Data System (ADS)

    Guo, Hongjian; Chen, Lansun

    2009-05-01

    A kind of predator-prey system with distributed time delay and impulsive harvest is firstly presented and then the effects of impulsive harvest on the system are discussed by means of chain transform. By using the Floquet's theory and the comparison theorem of impulsive differential equation, the thresholds between permanence and extinction of each species are obtained as functions of model parameters. It is proved that the impulsive period and the proportion of the impulsive harvest will ultimately affect the fate of each species. Finally, the theoretical results obtained in this paper are confirmed by numerical simulations.

  13. Effects of histamine H(1) receptor antagonists on delayed spatial win-shift task in rats.

    PubMed

    Okada, Akiko; Kato, Akane; Kamei, Chiaki

    2010-04-10

    We investigated the effects of histamine H(1) receptor antagonists in 3 different stages of spatial working memory in comparison with scopolamine. The effects of drugs were measured using an eight-arm radial maze with a delayed spatial win-shift task in rats. Drugs were injected 10 min before the training phase (timing 1), immediately after the training phase (timing 2), or 10 min before the test phase (timing 3). Intrahippocampal injection of pyrilamine and diphenhydramine resulted in significant effects on the number of correct choices and across-phase errors in all 3 timings. Scopolamine impaired the number of correct choices and across-phase errors in timing 1 and 3; however, no significant effect was observed in timing 2. These results indicate that pyrilamine and diphenhydramine impaired encoding, retention and retrieval processes of spatial working memory, whereas scopolamine did not impair the retention process. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  14. ERP correlates of the incidental retrieval of emotional information: effects of study-test delay.

    PubMed

    Jaeger, Antonio; Johnson, Jeffrey D; Corona, Maria; Rugg, Michael D

    2009-05-07

    Prior studies indicate that, in tests of recognition memory, ERPs elicited by correctly recognized test items differ according to whether the items were encoded in an emotionally arousing or an emotionally neutral study context. These prior studies employed only a relatively brief (ca. 10 min) retention interval, however. The present study contrasted the ERP correlates of incidental emotional retrieval as a function of study-test delay. Pictures of emotionally neutral objects were encoded in association with either emotionally negative or emotionally neutral scenes. In a repeated measures design (N=19), half of the objects were subjected to a recognition memory test 10 min after completion of the study phase, whereas the remainder were tested 24 h later. After the short delay, ERPs elicited by objects paired with emotional vs. neutral backgrounds differed from around 200 ms post-stimulus, the objects paired with the emotional scenes eliciting the more positive-going waveforms. After 24 h, differences between the ERPs elicited by the two classes of object were still apparent from around 200 ms post-stimulus. Strikingly, these effects differed from those obtained 10 min after study in both their polarity and scalp distribution. The early onset of these ERP effects suggests that they may reflect a form of memory independent of the conscious recollection of the associated study contexts. The qualitative differences in the effects at the two retention intervals raise the possibility that the encoded objects were subjected to consolidation processes that differed according to the emotional attributes of their study contexts.

  15. Further evidence for the role of gap junctions in the delayed antiarrhythmic effect of cardiac pacing.

    PubMed

    Miskolczi, Gottfried; Gönczi, Márton; Kovács, Mária; Seprényi, György; Végh, Ágnes

    2015-07-01

    The objective of this study was to provide evidence that gap junctions are involved in the delayed antiarrhythmic effect of cardiac pacing. Twenty-four dogs were paced through the right ventricle (4 × 5 min, rate of 240 beats/min) 24 h prior to a 25 min occlusion of the left anterior descending coronary artery. Some of these paced dogs were infused with 50 (n = 7) or 100 μmol/L (n = 7) of the gap junction uncoupler carbenoxolone (CBX), prior to and during the occlusion. Ten sham-paced dogs, subjected only to occlusion, served as the controls. Cardiac pacing markedly reduced the number of ectopic beats and episodes of ventricular tachycardia (VT), as well the incidence of VT and ventricular fibrillation during occlusion. The changes in severity of ischaemia and tissue electrical resistance were also less marked compared with the unpaced controls. Pacing also preserved the permeability of gap junctions, the phosphorylation of connexin43, and the structural integrity of the intercalated discs. The closing of gap junctions with CBX prior to and during ischaemia markedly attenuated or even abolished these protective effects of pacing. Our results support the previous findings that gap junctions play a role in the delayed antiarrhythmic effect of cardiac pacing.

  16. Special Effects: Antenna Wetting, Short Distance Diversity and Depolarization

    NASA Technical Reports Server (NTRS)

    Acosta, Roberto J.

    2000-01-01

    The Advanced Communication Technology Satellite (ACTS) communications system operates in the Ka frequency band. ACTS uses multiple, hopping, narrow beams and very small aperture terminal (VSAT) technology to establish a system availability of 99.5% for bit-error-rates of 5 x 10(exp -7) Or better over the continental United States. In order maintain this minimum system availability in all US rain zones, ACTS uses an adaptive rain fade compensation protocol to reduce the impact of signal attenuation resulting from propagation effects. The purpose of this paper is to present the results of system and sub-system characterizations considering the statistical effects of system variances due to antenna wetting and depolarization effects. In addition the availability enhancements using short distance diversity in a sub-tropical rain zone are investigated.

  17. EMBEDDED LENSING TIME DELAYS, THE FERMAT POTENTIAL, AND THE INTEGRATED SACHS–WOLFE EFFECT

    SciTech Connect

    Chen, Bin; Kantowski, Ronald; Dai, Xinyu

    2015-05-01

    We derive the Fermat potential for a spherically symmetric lens embedded in a Friedman–Lemaître–Robertson–Walker cosmology and use it to investigate the late-time integrated Sachs–Wolfe (ISW) effect, i.e., secondary temperature fluctuations in the cosmic microwave background (CMB) caused by individual large-scale clusters and voids. We present a simple analytical expression for the temperature fluctuation in the CMB across such a lens as a derivative of the lens’ Fermat potential. This formalism is applicable to both linear and nonlinear density evolution scenarios, to arbitrarily large density contrasts, and to all open and closed background cosmologies. It is much simpler to use and makes the same predictions as conventional approaches. In this approach the total temperature fluctuation can be split into a time-delay part and an evolutionary part. Both parts must be included for cosmic structures that evolve and both can be equally important. We present very simple ISW models for cosmic voids and galaxy clusters to illustrate the ease of use of our formalism. We use the Fermat potentials of simple cosmic void models to compare predicted ISW effects with those recently extracted from WMAP and Planck data by stacking large cosmic voids using the aperture photometry method. If voids in the local universe with large density contrasts are no longer evolving we find that the time delay contribution alone predicts values consistent with the measurements. However, we find that for voids still evolving linearly, the evolutionary contribution cancels a significant part of the time delay contribution and results in predicted signals that are much smaller than recently observed.

  18. A Novel Approach to Delayed-Start Analyses for Demonstrating Disease-Modifying Effects in Alzheimer’s Disease

    PubMed Central

    Liu-Seifert, Hong; Andersen, Scott W.; Lipkovich, Ilya; Holdridge, Karen C.; Siemers, Eric

    2015-01-01

    One method for demonstrating disease modification is a delayed-start design, consisting of a placebo-controlled period followed by a delayed-start period wherein all patients receive active treatment. To address methodological issues in previous delayed-start approaches, we propose a new method that is robust across conditions of drug effect, discontinuation rates, and missing data mechanisms. We propose a modeling approach and test procedure to test the hypothesis of noninferiority, comparing the treatment difference at the end of the delayed-start period with that at the end of the placebo-controlled period. We conducted simulations to identify the optimal noninferiority testing procedure to ensure the method was robust across scenarios and assumptions, and to evaluate the appropriate modeling approach for analyzing the delayed-start period. We then applied this methodology to Phase 3 solanezumab clinical trial data for mild Alzheimer’s disease patients. Simulation results showed a testing procedure using a proportional noninferiority margin was robust for detecting disease-modifying effects; conditions of high and moderate discontinuations; and with various missing data mechanisms. Using all data from all randomized patients in a single model over both the placebo-controlled and delayed-start study periods demonstrated good statistical performance. In analysis of solanezumab data using this methodology, the noninferiority criterion was met, indicating the treatment difference at the end of the placebo-controlled studies was preserved at the end of the delayed-start period within a pre-defined margin. The proposed noninferiority method for delayed-start analysis controls Type I error rate well and addresses many challenges posed by previous approaches. Delayed-start studies employing the proposed analysis approach could be used to provide evidence of a disease-modifying effect. This method has been communicated with FDA and has been successfully applied to

  19. A novel approach to delayed-start analyses for demonstrating disease-modifying effects in Alzheimer's disease.

    PubMed

    Liu-Seifert, Hong; Andersen, Scott W; Lipkovich, Ilya; Holdridge, Karen C; Siemers, Eric

    2015-01-01

    One method for demonstrating disease modification is a delayed-start design, consisting of a placebo-controlled period followed by a delayed-start period wherein all patients receive active treatment. To address methodological issues in previous delayed-start approaches, we propose a new method that is robust across conditions of drug effect, discontinuation rates, and missing data mechanisms. We propose a modeling approach and test procedure to test the hypothesis of noninferiority, comparing the treatment difference at the end of the delayed-start period with that at the end of the placebo-controlled period. We conducted simulations to identify the optimal noninferiority testing procedure to ensure the method was robust across scenarios and assumptions, and to evaluate the appropriate modeling approach for analyzing the delayed-start period. We then applied this methodology to Phase 3 solanezumab clinical trial data for mild Alzheimer's disease patients. Simulation results showed a testing procedure using a proportional noninferiority margin was robust for detecting disease-modifying effects; conditions of high and moderate discontinuations; and with various missing data mechanisms. Using all data from all randomized patients in a single model over both the placebo-controlled and delayed-start study periods demonstrated good statistical performance. In analysis of solanezumab data using this methodology, the noninferiority criterion was met, indicating the treatment difference at the end of the placebo-controlled studies was preserved at the end of the delayed-start period within a pre-defined margin. The proposed noninferiority method for delayed-start analysis controls Type I error rate well and addresses many challenges posed by previous approaches. Delayed-start studies employing the proposed analysis approach could be used to provide evidence of a disease-modifying effect. This method has been communicated with FDA and has been successfully applied to actual

  20. Effects of methylphenidate on sensitivity to reinforcement delay and to reinforcement amount in pigeons: Implications for impulsive choice.

    PubMed

    Pitts, Raymond C; Cummings, Craig W; Cummings, Carol; Woodcock, Rebecca L; Hughes, Christine E

    2016-12-01

    Methylphenidate has been shown to decrease impulsive choice (increase choices of a larger more delayed reinforcer). The purpose of this study was to investigate 2 potential behavioral mechanisms of this effect: a drug-induced change in control by reinforcement delay (Experiment 1) and/or by reinforcement amount (Experiment 2). In Experiment 1, pigeons responded under a rapid-acquisition, concurrent-chains choice procedure involving delay to reinforcement; the option with the shorter delay varied unpredictably across sessions. The pigeons accurately tracked the shorter delay across sessions (i.e., a preference for the option with the shorter delay developed within each session). Methylphenidate selectively decreased sensitivity to reinforcement delay-it attenuated the acquisition of preference at doses that did not systematically affect bias or response rates. In Experiment 2, pigeons responded under a rapid-acquisition, concurrent-chains choice procedure involving reinforcement amount. The pigeons accurately tracked the option with the larger reinforcement amount across sessions. Methylphenidate selectively decreased sensitivity to reinforcement amount-it attenuated the acquisition of preference at doses that did not systematically affect bias or response rates. These data suggest that methylphenidate attenuates the degree to which the various reinforcement dimensions control choice, and that drug effects on impulsive choice depend upon the relative contributions of drug-induced changes in control of behavior by each relevant dimension. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  1. Delayed development induced by toxicity to the host can be inherited by a bacterial-dependent, transgenerational effect

    PubMed Central

    Fridmann-Sirkis, Yael; Stern, Shay; Elgart, Michael; Galili, Matana; Zeisel, Amit; Shental, Noam; Soen, Yoav

    2014-01-01

    Commensal gut bacteria in many species including flies are integral part of their host, and are known to influence its development and homeostasis within generation. Here we report an unexpected impact of host–microbe interactions, which mediates multi-generational, non-Mendelian inheritance of a stress-induced phenotype. We have previously shown that exposure of fly larvae to G418 antibiotic induces transgenerationally heritable phenotypes, including a delay in larval development, gene induction in the gut and morphological changes. We now show that G418 selectively depletes commensal Acetobacter species and that this depletion explains the heritable delay, but not the inheritance of the other phenotypes. Notably, the inheritance of the delay was mediated by a surprising trans-generational effect. Specifically, bacterial removal from F1 embryos did not induce significant delay in F1 larvae, but nonetheless led to a considerable delay in F2. This effect maintains a delay induced by bacterial-independent G418 toxicity to the host. In line with these findings, reintroduction of isolated Acetobacter species prevented the inheritance of the delay. We further show that this prevention is partly mediated by vitamin B2 (Riboflavin) produced by these bacteria; exogenous Riboflavin led to partial prevention and inhibition of Riboflavin synthesis compromised the ability of the bacteria to prevent the inheritance. These results identify host–microbe interactions as a hitherto unrecognized factor capable of mediating non-Mendelian inheritance of a stress-induced phenotype. PMID:24611070

  2. Food webs obscure the strength of plant diversity effects on primary productivity.

    PubMed

    Seabloom, Eric W; Kinkel, Linda; Borer, Elizabeth T; Hautier, Yann; Montgomery, Rebecca A; Tilman, David

    2017-04-01

    Plant diversity experiments generally find that increased diversity causes increased productivity; however, primary productivity is typically measured in the presence of a diverse food web, including pathogens, mutualists and herbivores. If food web impacts on productivity vary with plant diversity, as predicted by both theoretical and empirical studies, estimates of the effect of plant diversity on productivity may be biased. We experimentally removed arthropods, foliar fungi and soil fungi from the longest-running plant diversity experiment. We found that fungi and arthropods removed a constant, large proportion of biomass leading to a greater reduction of total biomass in high diversity plots. As a result, the effect of diversity on measured plant productivity was much higher in the absence of fungi and arthropods. Thus, diversity increases productivity more than reported in previous studies that did not control for the effects of heterotrophic consumption.

  3. Effect of structurally diverse peroxisome proliferators on rat hepatic sulfotransferase.

    PubMed

    Witzmann, F; Coughtrie, M; Fultz, C; Lipscomb, J

    1996-01-05

    Exposure to perfluorocarboxylic acids, pthalate esters, and some hypolipidemic agents results in the proliferation of peroxisomes in the rodent liver. The structural diversity of these compounds suggests mechanistic diversity in their toxicity as well. To establish reliable biomarkers of peroxisome proliferation (PP) in compounds with distinct chemical toxicities, this study investigated the effect of in vivo exposure to perfluoro-n-octanoic acid, perfluoro-n-decanoic acid, di(2-ethylhexyl)phthalate (DEHP) and clofibrate on two-dimensional electrophoretic protein patterns of rat hepatic sulfotransferases, ST1A1, ST1C1 and ST2A1. After exposure to peroxisome proliferative doses, both ST1A1 and ST1C1 abundance in whole liver homogenates was significantly reduced, but only as a result of perfluorocarboxylic and exposure. The well-established PPs, DEHP and clofibrate had no effect on sulfotransferase expression whatsoever. The observed down-regulation of these STs is significant with respect to their normal detoxication activities and its potential correlation to carcinogenesis warrants further study. The present investigation supports previous studies that demonstrate the unique features of perfluorocarboxylic acid toxicity, relative to classic peroxisome proliferators and endorses the continued use of 2D protein-mapping of Sts and other proteins as biomarkers of chemical toxicity.

  4. Direct measurement of the wigner delay associated with the goos-Hanchen effect

    PubMed

    Chauvat; Emile; Bretenaker; Le Floch A

    2000-01-03

    It is shown experimentally that the nonspecular reflection of light on an interface induces a time delay, as predicted by Wigner's scattering theory. A differential femtosecond technique is used to directly isolate this delay, associated with the Goos-Hanchen spatial shift produced by a grating near a resonant Wood anomaly. A delay of 4.4 fs is observed between TE and TM pulses, in agreement with the expected Wigner delay obtained from phase shift dispersion measurements.

  5. Effect of delayed feedback on the dynamics of a scalar map via a frequency-domain approach.

    PubMed

    Gentile, Franco S; Bel, Andrea L; Belén D'Amico, M; Moiola, Jorge L

    2011-06-01

    The effect of delayed feedback on the dynamics of a scalar map is studied by using a frequency-domain approach. Explicit conditions for the occurrence of period-doubling and Neimark-Sacker bifurcations in the controlled map are found analytically. The appearance of a 1:2 resonance for certain values of the delay is also formalized, revealing that this phenomenon is independent of the system parameters. A detailed study of the well-known logistic map under delayed feedback is included for illustration.

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

    ERIC Educational Resources Information Center

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

    2011-01-01

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

  7. Alteration in delayed fluorescence characterize the effect of heat stress on plants

    NASA Astrophysics Data System (ADS)

    Zeng, Lizhang; Xing, Da

    2005-02-01

    High temperature affects the photosynthetic functions of plants by its effects on the rate of chemical reactions and on structural organization. Delayed fluorescence originated from the reaction center of photosystem II (PSII) during the photosynthesis process shortly after stopped illumination. With lamina of soybean as a testing model, the effects of high temperature stress on plant photosynthesis capability were studied with various spectral analysis methods. Experimental results show that DF spectrum and Excitation spectrum can probably characterize the changes of soybean photosynthesis capability after different high temperature treatments. Meanwhile, the injury and harm degree of heat stress on soybean leaves were further studied by the variability of its chloroplast absorption spectrum. DF spectroscopy method may provide a new approach for fast detection of the effects of environment stresses on plant photosynthesis capability.

  8. Circadian phase-delaying effects of bright light alone and combined with exercise in humans.

    PubMed

    Youngstedt, Shawn D; Kripke, Daniel F; Elliott, Jeffrey A

    2002-01-01

    In a within-subjects (n = 18), counterbalanced design, the circadian phase-shifting effects of 3 h of 1) bright light (3,000 lx) alone 2) and bright light combined with vigorous exercise were compared. For each treatment, volunteers spent 3 nights and 2 days in the laboratory, typically receiving the treatment from approximately 2300 to 0200 on night 2. Bedtimes and waketimes were fixed to the volunteers' habits. Illumination was 50 lx during other wake hours and 0 lx during sleep. Bright Light Alone elicited a significant phase delay in rectal temperature minimum (70 min), but not in urinary 6-sulphatoxymelatonin (6-SMT) acrophase (20 min). Bright Light + Exercise elicited a significant phase delay in 6-SMT (68 min), but did not result in a significant difference in shift compared with Bright Light Alone. The study had adequate statistical power (80%) to detect phase-shift differences between treatments of approximately 2-2.5 h. Thus any antagonism of light shifts with exercise could not have been revealed. Within the limited exercise and light parameters of this study, the results suggest that exercise does not reliably modulate phase-shifting effects of late night bright light in humans.

  9. Effect of advanced and delayed rotation on the dominant flow pattern and its temporal evolution

    NASA Astrophysics Data System (ADS)

    Uksul, Esra; Krishna, Swathi; Mulleners, Karen

    2015-11-01

    During a flapping cycle of an insect, complex time dependent flows are produced as the wing reciprocates, producing a maximum lift at the stroke reversals. By flipping the wing rapidly at the end of each stroke, the insect modulates the flow around the wing and hence the aerodynamic forces necessary to hover. The duration and starting point of the flip play an important role in determining the amount of lift produced. To understand and tailor the effect of wing kinematics on the aerodynamic performance we focussed on the vortex dynamics of the flow field. Phase-averaged data from particle image velocimetry was used to evaluate the flow features inherent to changes in rotation during a stroke of a flat plate, which is modelled based on hoverfly characteristics. The period of rotation is one-third of the total time period. A +10% phase shift is used for delayed rotation, a -10% phase shift for advanced rotation. Vortex detection methods like the λ2 and Γ2 criteria are used to determine the effect of a delay or early rotation on the trajectories, size, shape and location of the prominent vortical structures. Proper orthogonal decomposition is used to study the influence of the phase-shifts on the dominant mode structure and the related time-scales.

  10. Effect of Whirlpool Therapy on the Signs and Symptoms of Delayed-Onset Muscle Soreness

    PubMed Central

    Kuligowski, Lori A.; Lephart, Scott M.; Giannantonio, Frank P.; Blanc, Rob O.

    1998-01-01

    Objective: To determine the efficacy of warm whirlpool, cold whirlpool, and contrast therapy in the treatment of delayed-onset muscle soreness. Design and Setting: Subjects performed eccentric contractions of the elbow flexors and received 4 treatments: immediately postexercise and 24, 48, and 72 hours postexercise. Treatments consisted of 24-minute treatments with warm whirlpool, cold whirlpool, contrast therapy, or no treatment. Subjects: Fifty-six sex-matched volunteers from the University of Pittsburgh. Measurements: Measurements were taken at 5 assessment times: pre-exercise (0 hours); prior to treatment at 24, 48, and 72 hours postexercise; and at 96 hours postexercise. Dependent variables were degrees of resting elbow flexion, active elbow flexion, and extension; perceived soreness values on a Graphic Pain Rating Scale; and maximal voluntary isometric contraction. A repeated-measures analysis of variance (group by time) and Tukey post hoc analysis were used to determine which treatment groups differed significantly in returning subjects to pre-exercise values. Results: Cold whirlpool and contrast therapy were found to return subjects to baseline values of resting elbow flexion and perceived soreness significantly more than warm whirlpool or no treatment (P < .01). Additionally, warm whirlpool was found to be more effective than no treatment in the return of resting elbow flexion (P < .01). Conclusions: These results suggest that cold whirlpool and contrast therapy are more effective than warm whirlpool or no treatment in alleviating delayed-onset muscle soreness in the elbow flexors. PMID:16558514

  11. Effects of therapeutic massage on gait and pain after delayed onset muscle soreness

    PubMed Central

    Han, Jun-Ho; Kim, Min-Jeong; Yang, Hyuk-Jin; Lee, Yu-Jin; Sung, Yun-Hee

    2014-01-01

    Unfamiliar or sudden exercise can induce delayed onset muscle soreness (DOMS) within 12–24 h. So, several researchers have reported various interventions to treat DOMS. Massage is generally known to eliminate muscle fatigue. However, effect of massage after DOMS is still not clear. We investigated whether the massage is effective on pain and gait after DOMS. The participants were divided into a control group (n= 10) with DOMS and an experimental group (n= 11) with the massage treated after DOMS. We induced DOMS by taking isotonic exercise with going up and down 20 times in 5-story building. We applied the massage and assessment on gastrocnemius of dominant foot. The change of gait and pain was assessed using gaitrite and algometer. In the present results, the massage on gastrocnemius after DOMS showed significant difference in pain (P< 0.05). Also, there was a significant difference in gait (P< 0.05), especially, spatial parameters (distance, step length, stride length) and temporal parameters (ambulation, heel on off time, stride velocity). Moreover, the pain relief after massage-treated in DOMS correlated with gait. These results suggest that the massage on gastrocnemius after DOMS has influence on pain and gait performance. Therefore, massage can be applied as intervention for delayed onset muscle soreness. PMID:24877051

  12. Effects of therapeutic massage on gait and pain after delayed onset muscle soreness.

    PubMed

    Han, Jun-Ho; Kim, Min-Jeong; Yang, Hyuk-Jin; Lee, Yu-Jin; Sung, Yun-Hee

    2014-04-01

    Unfamiliar or sudden exercise can induce delayed onset muscle soreness (DOMS) within 12-24 h. So, several researchers have reported various interventions to treat DOMS. Massage is generally known to eliminate muscle fatigue. However, effect of massage after DOMS is still not clear. We investigated whether the massage is effective on pain and gait after DOMS. The participants were divided into a control group (n= 10) with DOMS and an experimental group (n= 11) with the massage treated after DOMS. We induced DOMS by taking isotonic exercise with going up and down 20 times in 5-story building. We applied the massage and assessment on gastrocnemius of dominant foot. The change of gait and pain was assessed using gaitrite and algometer. In the present results, the massage on gastrocnemius after DOMS showed significant difference in pain (P< 0.05). Also, there was a significant difference in gait (P< 0.05), especially, spatial parameters (distance, step length, stride length) and temporal parameters (ambulation, heel on off time, stride velocity). Moreover, the pain relief after massage-treated in DOMS correlated with gait. These results suggest that the massage on gastrocnemius after DOMS has influence on pain and gait performance. Therefore, massage can be applied as intervention for delayed onset muscle soreness.

  13. Effect of surface reactions on ignition delay of methanol/air mixture

    NASA Astrophysics Data System (ADS)

    Huo, J. P.; Yang, H. L.; Jiang, L. Q.; Wang, X. H.; Zhao, D. Q.

    2014-11-01

    A surface reaction kinetic model for the combustion of methanol/air mixture was developed in order to investigate the ignition inhibitory mechanism of wall on the premixed gas in a micro closed volume. In this model, except for H, O, OH and CH3 radicals, the absorption of hydrogen peroxide and hydroperoxyl on the surface were also considered. By applying CHEMKIN-Pro software, the model was integrated into the calculation of homogeneous combustion process of gas mixture. Surface reactions were found resulting in the increase of ignition delay time. The sensitivity analysis showed that the loss of hydrogen peroxide on the wall was the main reason, due to the direct suppression effect on the generation and accumulation of OH in the radical pool. However, the loss of hydroperoxyl would take the place of hydrogen peroxide as the main inhibitory factor when the sticking coefficient became as large as the order of 10-3. In addition, the ignition delay time increased with sticking coefficient or surface-area-to-volume ratio. Enhancing the initial temperature of premixed gas was able to reduce the inhibitory effect of surface reactions.

  14. Short- and long-delay intracranial ERP repetition effects dissociate memory systems in the human brain.

    PubMed

    Guillem, F; Rougier, A; Claverie, B

    1999-07-01

    Prior exposure to a stimulus can facilitate the performance to subsequent presentations of that stimulus. ERP studies have shown that this facilitation is associated with the modulation of two components (N400 and P600). Investigation of the time course of both behavioral and ERP repetition effects have led to the assumption that it is subserved by the combination of at least two mechanisms operating at different time-points: a short-delay semantic activation and a long-lasting episodic mechanism. The present experiment recorded intracranial ERPs from various structures during a continuous recognition memory task to investigate the respective contribution of the different brain regions to short- and long-delay ERP repetition effects. The results are in good agreement with both the classical neuropsychological literature and the more recent data obtained with functional imagery techniques. They provide electrophysiological evidence of multiple anatomo-functional memory systems in the human brain: a short-term semantic activation system and a long-term episodic memory system, with interface structures that coordinate the functioning of these two systems.

  15. Effective delayed neutron fraction measurement in the critical VENUS-F reactor using noise techniques

    SciTech Connect

    Doligez, X.

    2015-07-01

    This paper present the measurements of VENUS-F kinetic parameters using the Rossi-Alpha methods. The VENUS-F reactor is a zero-power reactor based in Mol, Belgium at SCK-CEN where the fuel is made of metallic enriched uranium with pure lead in order to simulate the behavior of lead fast reactor. The reactor can be operated under critical when it is coupled with GENEPI-3C. At the beginning of 2014, a measurement campaign was performed in order to estimate the kinetics parameters. In this paper, two measurements are analyzed at two different powers (approximately 2 W and 30 W) with 7 different fission chambers (with a 235-U deposit that varies from 1 g to 10 mg). All the correlation functions needed for the Rossi-Alpha method have been built for each possible set of two detectors in each configuration and values obtained from those functions for the effective delayed neutron fraction are then compared. The absolute necessity to operate at very low power is presented. The final value for the effective delayed neutron fraction is finally estimated to be 730 pcm ± 11 pcm and the prompt neutron generation time is estimated to be equal to 0,041 μseconds ± 0.04 μsec. (authors)

  16. Life in varying environments: experimental evidence for delayed effects of juvenile environment on adult life history.

    PubMed

    Helle, Heikki; Koskela, Esa; Mappes, Tapio

    2012-05-01

    1. The effects of environment experienced during early development on phenotype as an adult has started to gain vast amounts of interest in various taxa. Some evidence on long-term effects of juvenile environment is available, but replicated experimental studies in wild animals are still lacking. 2. Here we report the first replicated experiment in wild mammals which examines the long-term effects of juvenile and adult environments on individual fitness (reproduction, survival and health). The early development of bank vole (Myodes glareolus) individuals took place in either food-supplemented or un-supplemented outdoor enclosures. After the summer, adult individuals were reciprocally changed to either a similar or opposite resource environment to overwinter. 3. Adult environment had an overriding effect on reproductive success of females so that females overwintering in food-supplemented enclosures had a higher probability of breeding and advanced the initiation of breeding. However, the characteristics of their litters were determined by juvenile environment: females initially grown in food-supplemented conditions subsequently produced larger litters with bigger pups and a male-biased sex ratio. 4. In males, individuals growing in un-supplemented conditions had the highest survival irrespective of adult environment during winter, whereas in females, neither the juvenile nor adult environments affected their survival significantly. The physiological condition of voles in spring, as determined by haematological parameters, was also differentially affected by juvenile (plasma proteins and male testosterone) and adult (haematocrit) environments. 5. Our results suggest that (i) life-history trajectories of voles are not strictly specialized to a certain environment and (ii) the plastic life-history responses to present conditions can actually be caused by delayed effects of the juvenile environment. More generally, the results are important for understanding

  17. Effect of the Topology and Delayed Interactions in Neuronal Networks Synchronization

    PubMed Central

    Pérez, Toni; Garcia, Guadalupe C.; Eguíluz, Víctor M.; Vicente, Raúl; Pipa, Gordon; Mirasso, Claudio

    2011-01-01

    As important as the intrinsic properties of an individual nervous cell stands the network of neurons in which it is embedded and by virtue of which it acquires great part of its responsiveness and functionality. In this study we have explored how the topological properties and conduction delays of several classes of neural networks affect the capacity of their constituent cells to establish well-defined temporal relations among firing of their action potentials. This ability of a population of neurons to produce and maintain a millisecond-precise coordinated firing (either evoked by external stimuli or internally generated) is central to neural codes exploiting precise spike timing for the representation and communication of information. Our results, based on extensive simulations of conductance-based type of neurons in an oscillatory regime, indicate that only certain topologies of networks allow for a coordinated firing at a local and long-range scale simultaneously. Besides network architecture, axonal conduction delays are also observed to be another important factor in the generation of coherent spiking. We report that such communication latencies not only set the phase difference between the oscillatory activity of remote neural populations but determine whether the interconnected cells can set in any coherent firing at all. In this context, we have also investigated how the balance between the network synchronizing effects and the dispersive drift caused by inhomogeneities in natural firing frequencies across neurons is resolved. Finally, we show that the observed roles of conduction delays and frequency dispersion are not particular to canonical networks but experimentally measured anatomical networks such as the macaque cortical network can display the same type of behavior. PMID:21637767

  18. Effect of metoclopramide on normal and delayed gastric emptying in gastroesophageal reflux patients

    SciTech Connect

    Fink, S.M.; Lange, R.C.; McCallum, R.W.

    1983-12-01

    Gastric emptying has an important role in the pathophysiology of gastroesophageal reflux disease. The effect of metoclopramide, a gastric prokinetic agent, in gastroesophageal reflux patients with normal as well as delayed emptying was investigated. Twenty-six patients with subjective and objective evidence of gastroesophageal reflux ingested an egg salad sandwich meal labeled with /sub 99m/technetium-DTPA for a baseline study, and then again on a separate day after receiving oral metoclopramide, 10 mg, 30 min prior to the test meal. The mean percent isotope remaining in the stomach after 90 min improved significantly from 70.3 +/- 3.9% (SEM) to 55.2 +/- 4.2% after metoclopramide. Fourteen (54%) had a basal emptying in the normal range of 34-69% retention of isotope at 90 min, (means +/- 2 SD), while it was slow in 12 (46%). For those with delayed basal gastric emptying, the mean retention of 88.9 +/- 2.9% at 90 min was significantly decreased by metoclopramide to 68.6 +/- 6.1%. In those patients with a normal basal gastric emptying and a mean retention of 54.4 +/- 2.3% at 90 min, there was also significant improvement (P less than 0.025) to 43.6 +/- 3.6% after metoclopramide. These data indicate that metoclopramide increased gastric emptying in gastroesophageal reflux patients with normal as well as delayed gastric emptying. Therefore on a patient management level a trial of metoclopramide is warranted in patients with gastroesophageal reflux disease and is not limited by the gastric emptying status of the patient.

  19. Effect of diagnostic delay on survival in patients with colorectal cancer: a retrospective cohort study.

    PubMed

    Pita-Fernández, Salvador; González-Sáez, Luis; López-Calviño, Beatriz; Seoane-Pillado, Teresa; Rodríguez-Camacho, Elena; Pazos-Sierra, Alejandro; González-Santamaría, Paloma; Pértega-Díaz, Sonia

    2016-08-22

    Disparate and contradictory results make studies necessary to investigate in more depth the relationship between diagnostic delay and survival in colorectal cancer (CRC) patients. The aim of this study is to analyse the relationship between the interval from first symptom to diagnosis (SDI) and survival in CRC. Retrospective study of n = 942 CRC patients. SDI was calculated as the time from the diagnosis of cancer and the first symptoms of CRC. Cox regression was used to estimate five-year mortality hazard ratios as a function of SDI, adjusting for age and gender. SDI was modelled according to SDI quartiles and as a continuous variable using penalized splines. Median SDI was 3.4 months. SDI was not associated with stage at diagnosis (Stage I = 3.6 months, Stage II-III = 3.4, Stage IV = 3.2; p = 0.728). Shorter SDIs corresponded to patients with abdominal pain (2.8 months), and longer SDIs to patients with muchorrhage (5.2 months) and rectal tenesmus (4.4 months). Adjusting for age and gender, in rectum cancers, patients within the first SDI quartile had lower survival (p = 0.003), while in colon cancer no significant differences were found (p = 0.282). These results do not change after adjusting for TNM stage. The splines regression analysis revealed that, for rectum cancer, 5-year mortality progressively increases for SDIs lower than the median (3.7 months) and decreases as the delay increases until approximately 8 months. In colon cancer, no significant relationship was found between SDI and survival. Short diagnostic intervals are significantly associated with higher mortality in rectal but not in colon cancers, even though a borderline significant effect is also observed in colon cancer. Longer diagnostic intervals seemed not to be associated with poorer survival. Other factors than diagnostic delay should be taken into account to explain this "waiting-time paradox".

  20. Effect of the topology and delayed interactions in neuronal networks synchronization.

    PubMed

    Pérez, Toni; Garcia, Guadalupe C; Eguíluz, Víctor M; Vicente, Raúl; Pipa, Gordon; Mirasso, Claudio

    2011-01-01

    As important as the intrinsic properties of an individual nervous cell stands the network of neurons in which it is embedded and by virtue of which it acquires great part of its responsiveness and functionality. In this study we have explored how the topological properties and conduction delays of several classes of neural networks affect the capacity of their constituent cells to establish well-defined temporal relations among firing of their action potentials. This ability of a population of neurons to produce and maintain a millisecond-precise coordinated firing (either evoked by external stimuli or internally generated) is central to neural codes exploiting precise spike timing for the representation and communication of information. Our results, based on extensive simulations of conductance-based type of neurons in an oscillatory regime, indicate that only certain topologies of networks allow for a coordinated firing at a local and long-range scale simultaneously. Besides network architecture, axonal conduction delays are also observed to be another important factor in the generation of coherent spiking. We report that such communication latencies not only set the phase difference between the oscillatory activity of remote neural populations but determine whether the interconnected cells can set in any coherent firing at all. In this context, we have also investigated how the balance between the network synchronizing effects and the dispersive drift caused by inhomogeneities in natural firing frequencies across neurons is resolved. Finally, we show that the observed roles of conduction delays and frequency dispersion are not particular to canonical networks but experimentally measured anatomical networks such as the macaque cortical network can display the same type of behavior.

  1. Using additive modelling to quantify the effect of chemicals on phytoplankton diversity and biomass.

    PubMed

    Viaene, K P J; De Laender, F; Van den Brink, P J; Janssen, C R

    2013-04-01

    Environmental authorities require the protection of biodiversity and other ecosystem properties such as biomass production. However, the endpoints listed in available ecotoxicological datasets generally do not contain these two ecosystem descriptors. Inferring the effects of chemicals on such descriptors from micro- or mesocosm experiments is often hampered by inherent differences in the initial biodiversity levels between experimental units or by delayed community responses. Here we introduce additive modelling to establish the effects of a chronic application of the herbicide linuron on 10 biodiversity indices and phytoplankton biomass in microcosms. We found that communities with a low (high) initial biodiversity subsequently became more (less) diverse, indicating an equilibrium biodiversity status in the communities considered here. Linuron adversely affected richness and evenness while dominance increased but no biodiversity indices were different from the control treatment at linuron concentrations below 2.4 μg/L. Richness-related indices changed at lower linuron concentrations (effects noticeable from 2.4 μg/L) than other biodiversity indices (effects noticeable from 14.4 μg/L) and, in contrast to the other indices, showed no signs of recovery following chronic exposure. Phytoplankton biomass was unaffected by linuron due to functional redundancy within the phytoplankton community. Comparing thresholds for biodiversity with conventional toxicity test results showed that standard ecological risk assessments also protect biodiversity in the case of linuron.

  2. The effects of acute and repeated pyridostigmine bromide administration on response acquisition with immediate and delayed reinforcement.

    PubMed

    van Haaren, F; De Jongh, R; Hoy, J B; Karlix, J L; Schmidt, C J; Tebbett, I R; Wielbo, D

    1999-02-01

    This experiment was designed to assess the effects of acute and repeated administration of pyridostigmine bromide (a carbamate with prophylactic and therapeutic uses) on response acquisition. Experimentally naïve, male Sprague-Dawley rats were exposed to a situation in which lever presses were either immediately followed by food-pellet presentation or after a 16-s resetting delay. Different groups of rats received either one acute administration of pyridostigmine bromide (10 mg/kg, by gavage) or repeated pyridostigmine administration for 7 days (1.5 mg/kg/day, by gavage). Other groups were treated with distilled water for the same period of time. Both acute and repeated pyridostigmine bromide administration decreased serum cholinesterase levels by approximately 50%, but neither treatment affected brain cholinesterase levels in our assay. Acute and repeated drug administration produced the same behavioral effects. Subjects exposed to the 0-s delay conditions obtained many more food pellets than those exposed to the 16-s delay conditions. Administration of pyridostigmine bromide delayed the onset of responding in some, but not all, of the subjects in the treated groups, independent of the delay condition to which they were exposed. Many more responses were observed on an inoperative lever during the 16-s delay conditions than during the 0-s delay conditions, especially during the 16-s delay condition in which subjects had received acute vehicle administration. Whether or not these effects of small doses of pyridostigmine bromide on response acquisition are of central or peripheral origin will need to be determined in future studies, as response acquisition in the present experiment may have been affected by pyridostigmine's effects on gastrointestinal functioning and/or motor activity.

  3. Anxiety Assessment in Methamphetamine - Sensitized and Withdrawn Rats: Immediate and Delayed Effects

    PubMed Central

    Miladi-gorji, Hossein; Fadaei, Atefeh; Bigdeli, Imanollah

    2015-01-01

    Objective: The anxiety profile in the stimulant-sensitized animals is not clear. Thus, this study was conducted to elucidate the effects of acute and chronic administration of methamphetamine (METH) on the anxiety profile. The aim of this study was to examine whether METH-sensitized rats would show an increase in the expression of anxiogenic-like behaviors and to determine whether a low dose of METH elicits behavioral sensitization. Methods: Rats were repeatedly given METH (2 mg/kg, s.c., once a day for 14 days), and the immediate and delayed effects of METH on the anxiety profile was compared considering 30 minutes (min) and 120 min after injections in METH-sensitized, withdrawn and intact rats using the elevated plus-maze (EPM), also, to re-challenge with a low dose of METH (0.5 mg/kg) in withdrawn groups. Results: Results have shown that METH-sensitized rats exhibited an increase in the open arm time and entries 120 min after injection compared to the control group. We found a reduction in the time spent in open arms for the immediate effects of METH (30 min after injection) in METH-sensitized rats as compared to the control group. In withdrawn rats, METH/METH groups exhibited an increase in the open arm time and entries than METH/Sal and Sal/METH groups. Conclusion: It was found that unlike delayed effects, an immediate effect of METH exhibited anxiogenic-like behaviors in METH-sensitized rats using the EPM. Also, results indicated that a low dose of METH is a potent stimulus for reinstatement of methamphetamine behavioral sensitization in a long withdrawn period. PMID:26877748

  4. The effect of delay in rehabilitation on outcome of severe traumatic brain injury.

    PubMed

    Tepas, Joseph J; Leaphart, Cynthia L; Pieper, Pam; Beaulieu, Cynthia L; Spierre, Louise R; Tuten, James D; Celso, Brian G

    2009-02-01

    potential for salvage (GCS scores 6, 7, 8), RE correlation increased to -0.457 (P = .011), whereas those with most severe injury (GCS scores 3, 4, 5) demonstrated a weaker correlation that was not significant. For children with most severe injury (GCS scores 3,4,5), the correlation of DeltaFIM was significant (-0.38; P = .035); however, RE was not. These data demonstrate the price of delay of comprehensive rehabilitation, especially for the most vulnerable TBI children with best potential for salvage. The "golden hour," which has become the mantra for continued refinement of systems of emergency and trauma care, must progress without interruption to the "golden day," during which comprehensive critical care seamlessly transitions to timely and aggressive rehabilitation to effect the greatest functional recovery.

  5. Transactional problem content in cost discounting: parallel effects for probability and delay.

    PubMed

    Jones, Stephen; Oaksford, Mike

    2011-05-01

    Four experiments investigated the effects of transactional content on temporal and probabilistic discounting of costs. Kusev, van Schaik, Ayton, Dent, and Chater (2009) have shown that content other than gambles can alter decision-making behavior even when associated value and probabilities are held constant. Transactions were hypothesized to lead to similar effects because the cost to a purchaser always has a linked gain, the purchased commodity. Gain amount has opposite effects on delay and probabilistic discounting (e.g., Benzion, Rapoport, & Yagil, 1989; Green, Myerson, & Ostaszewski, 1999), a finding that is not consistent with descriptive decision theory (Kahneman & Tversky, 1979; Loewenstein & Prelec, 1992). However, little or no effect on discounting has been observed for losses or costs. Experiment 1, using transactions, showed parallel effects for temporal and probabilistic discounting: Smaller amounts were discounted more than large amounts. As the cost rises, people value the commodity more, and they consequently discount less. Experiment 2 ruled out a possible methodological cause for this effect. Experiment 3 replicated Experiment 1. Experiment 4, using gambles, showed no effect for temporal discounting, because of the absence of the linked gain, but the same effect for probabilistic discounting, because prospects implicitly introduce a linked gain (Green et al., 1999; Prelec & Loewenstein, 1991). As found by Kusev et al. (2009), these findings are not consistent with decision theory and suggest closer attention should be paid to the effects of content on decision making.

  6. Reinforcement Delay Fading During Differential Reinforcement of Communication: The Effects of Signals on Response Maintenance

    PubMed Central

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

    2011-01-01

    Signals during delays to reinforcement may lessen reductions in responding that typically occur when there is a delay between a response and its reinforcer. Sparse applied research has been devoted to understanding the conditions under which responding may be maintained when delays to reinforcement are introduced. We evaluated the extent to which providing signals during delay fading affected responding in the context of differential reinforcement of communication responses. Three individuals were exposed to gradually increasing signaled and unsignaled reinforcement delays in multiple-schedule and/or withdrawal designs. Results for 2 of 3 participants suggested that (a) the presence of signals facilitated response maintenance under delayed reinforcement and (b) coordinated basic and applied research may advance both conceptual understanding and clinical outcomes of delayed reinforcement. PMID:21765548

  7. Effect propagation in a toxicokinetic/toxicodynamic model explains delayed effects on the growth of unicellular green algae Scenedesmus vacuolatus.

    PubMed

    Vogs, Carolina; Bandow, Nicole; Altenburger, Rolf

    2013-04-01

    Ecotoxicological standard tests assess toxic effects by exposing an organism to high concentrations over defined periods of time. To evaluate toxicity under field conditions such as fluctuating and pulsed exposures, process-based toxicokinetic/toxicodynamic (TK/TD) models may be used for extrapolation from the existing evidence. A TK/TD model was developed that simulates the effect on growth of the green algae Scenedesmus vacuolatus continuously exposed to the model chemicals norflurazon, triclosan, and N-phenyl-2-naphthylamine. A pharmacological time-response model describing the effects of anticancer treatments on cancer cell growth was adapted and modified to model the affected growth of synchronized algae cells. The TK/TD model simulates the temporal effect course by linking the ambient concentration of a chemical to the observable adverse effect via an internal concentration and a sequence of biological events in the organism. The parameters of the toxicodynamic model are related to the growth characteristics of algae cells, a no effect concentration, the chemical efficacy as well as the ability of recovery and repair, and the delay during damage propagation. The TK/TD model fits well to the observed algae growth. The effect propagation through cumulative cell damage explained the observed delayed responses better than just the toxicokinetics. The TK/TD model could facilitate the link between several effect levels within damage propagation, which prospectively may be helpful to model adverse outcome pathways and time-dependent mixture effects.

  8. The effect of friendly touch on delay-of-gratification in preschool children.

    PubMed

    Leonard, Julia A; Berkowitz, Talia; Shusterman, Anna

    2014-01-01

    Physical touch has many documented benefits, but past research has paid little attention to the effects of touch on children's development. Here, we tested the effect of touch on children's compliance behaviour in a modified delay-of-gratification task. Forty children (M = 59 months) were randomly assigned to a touch or no touch group. Children in the intervention condition received a friendly touch on the back while being told that they should wait for permission to eat a candy. Results showed that children in the touch condition waited an average of two minutes longer to eat the candy than children in the no touch condition. This finding has implications for the potential of using touch to promote positive behaviours in children.

  9. Effects of vibratory stimulations on maximal voluntary isometric contraction from delayed onset muscle soreness.

    PubMed

    Koh, Hyung-Woo; Cho, Sung-Hyoun; Kim, Cheol-Yong; Cho, Byung-Jun; Kim, Jin-Woo; Bo, Kak Hwang

    2013-09-01

    [Purpose] The aim of this study was to investigate the effect of vibratory stimulation on maximal voluntary isometric contraction (MVIC) from delayed onset muscle soreness (DOMS). [Subjects] Sixty healthy adults participated in this study. The exclusion criteria were orthopedic or neurologic disease. [Methods] The researchers induced DOMS in the musculus extensor carpi radialis longus of each participant. Subjects in the control group received no treatment. The ultrasound group received ultrasound treatment (intensity, 1.0 W/cm(2;) frequency 1 MHz; time, 10 minutes). The vibration group received vibration stimulation (frequency, 20 MHz; time, 10 minutes). Maximal voluntary isometric contraction (MVIC) was recorded at baseline, immediately after exercise, and 24, 48, and 72 hours after exercise. [Results] MVIC measurements showed statistically significant differences in the vibration group compared with the control group. [Conclusion] Vibratory stimulation had a positive effect on recovery of muscle function from DOMS.

  10. Effects of Vibratory Stimulations on Maximal Voluntary Isometric Contraction from Delayed Onset Muscle Soreness

    PubMed Central

    Koh, Hyung-Woo; Cho, Sung-Hyoun; Kim, Cheol-Yong; Cho, Byung-Jun; Kim, Jin-Woo; Bo, Kak Hwang

    2013-01-01

    [Purpose] The aim of this study was to investigate the effect of vibratory stimulation on maximal voluntary isometric contraction (MVIC) from delayed onset muscle soreness (DOMS). [Subjects] Sixty healthy adults participated in this study. The exclusion criteria were orthopedic or neurologic disease. [Methods] The researchers induced DOMS in the musculus extensor carpi radialis longus of each participant. Subjects in the control group received no treatment. The ultrasound group received ultrasound treatment (intensity, 1.0 W/cm2; frequency 1 MHz; time, 10 minutes). The vibration group received vibration stimulation (frequency, 20 MHz; time, 10 minutes). Maximal voluntary isometric contraction (MVIC) was recorded at baseline, immediately after exercise, and 24, 48, and 72 hours after exercise. [Results] MVIC measurements showed statistically significant differences in the vibration group compared with the control group. [Conclusion] Vibratory stimulation had a positive effect on recovery of muscle function from DOMS. PMID:24259922

  11. Effects of chronic administration of drugs of abuse on impulsive choice (delay discounting) in animal models.

    PubMed

    Setlow, Barry; Mendez, Ian A; Mitchell, Marci R; Simon, Nicholas W

    2009-09-01

    Drug-addicted individuals show high levels of impulsive choice, characterized by preference for small immediate over larger but delayed rewards. Although the causal relationship between chronic drug use and elevated impulsive choice in humans has been unclear, a small but growing body of literature over the past decade has shown that chronic drug administration in animal models can cause increases in impulsive choice, suggesting that a similar causal relationship may exist in human drug users. This article reviews this literature, with a particular focus on the effects of chronic cocaine administration, which have been most thoroughly characterized. The potential mechanisms of these effects are described in terms of drug-induced neural alterations in ventral striatal and prefrontal cortical brain systems. Some implications of this research for pharmacological treatment of drug-induced increases in impulsive choice are discussed, along with suggestions for future research in this area.

  12. The effect of time delay on control stability of an electromagnetic active tuned mass damper for vibration control

    NASA Astrophysics Data System (ADS)

    Hassan, A.; Torres-Perez, A.; Kaczmarczyk, S.; Picton, P.

    2016-05-01

    The aim of this paper is to investigate the effect of time delays on the stability of a zero-placement position and velocity feedback law for a vibratory system comprising harmonic excitation equipped with an electromagnetic active tuned mass damper (ATMD). The purpose of the active control is broadening the vibration attenuation envelope of a primary mass to a higher frequency region identified as from 50±0.5Hz with a passive tuned mass damper (TMD) to a wider range of 50±5Hz with an ATMD. Stability conditions of the closed-loop system are determined by studying the position of the system closed-loop poles after the introduction of time delays for different excitation frequencies. A computer simulation of the model predicted that the proposed control system is subject to instability after a critical time delay margin dependent upon the frequency of excitation and the finding were experimentally validated. Three solutions are derived and experimentally tested for minimising the effect of time delays on the stability of the control system. The first solution is associated with the introduction of more damping in the absorber system. The second incorporates using a time-delayed ATMD by tuning its original natural resonant frequency to beyond the nominal operational frequency range of the composite system. The third involves an online gain tuning of filter coefficients in a dual arrangement of low-pass and high-pass filters to eliminate the effect time delays by manipulating the signal phase shifts.

  13. Delayed effects of neutron irradiation on central nervous system microvasculature in the rat

    SciTech Connect

    Goodman, J.H.; McGregor, J.M.; Clendenon, N.R.; Gordon, W.A.; Yates, A.J.; Gahbauer, R.A.; Barth, R.F.; Fairchild, R.G.

    1988-01-01

    Pathologic examination of a series of 14 patients with malignant gliomas treated with BNCT showed well demarcated zones of radiation damage characterized by coagulation necrosis. Beam attenuation was correlated with edema, loss of parenchymal elements, demyelination, leukocytosis, and peripheral gliosis. Vascular disturbances consisted of endothelial swelling, medial and adventitial proliferation, fibrin impregnation, frequent thrombosis, and perivascular inflammation. Radiation changes appeared to be acute and delayed. The outcome of the patients in this series was not significantly different from the natural course of the disease, even though two of the patients had no residual tumor detected at the time of autopsy. The intensity of the vascular changes raised a suspicion that boron may have sequestered in vessel walls, resulting in selectively high doses of radiation to these structures (Asbury et al., 1972), or that there may have been high blood concentrations of boron at the time of treatment. The potential limiting effects of a vascular ischemic reaction in Boron Neutron Capture Therapy (BNCT) prompted the following study to investigate the delayed response of microvascular structures in a rat model currently being used for pre-clinical investigations. 8 refs., 3 figs., 1 tab.

  14. Effects of Inter-electrode Distance on Delayed Onset Muscle Soreness in Microcurrent Therapy.

    PubMed

    Lee, Jeong-Woo; Kang, Ji-Sun; Park, Soo-Ji; Yoon, Se-Won; Jeong, Seong-Kwan; Heo, Myoung

    2013-11-01

    [Purpose] This study examined the effect of the distance between the two electrodes on delayed onset muscle soreness during microcurrent therapy. [Methods] In this study 24 healthy women who hadn't exercised regularly for six months were selected and randomly divided into two groups. Delayed onset muscle soreness (DOMS) was induced and experimental Group 1 were given microcurrent treatment with the electrodes attached at a close distance evaluated. Experimental Group 2 received the same treatment with the electrodes attached at a greater distance apart. Visual analogue scale pain and the RIII reflex were evaluated after inducing DOMS and after one day, two days, three days and four days of microcurrent treatment. [Results] The visual analogue scale and amplitude of RIII amplitude only showed significant differences with the length of time of the treatment. [Conclusion] This study found that difference of interelectrode distance has no influence on VAS pain and the RIII reflex of DOMS. Although there were no significant differences in RIII amplitude, we suspect that it may be influenced by current parameters such as frequency and intensity.

  15. Effects of Inter-electrode Distance on Delayed Onset Muscle Soreness in Microcurrent Therapy

    PubMed Central

    Lee, Jeong-Woo; Kang, Ji-Sun; Park, Soo-Ji; Yoon, Se-Won; Jeong,, Seong-Kwan; Heo, Myoung

    2013-01-01

    [Purpose] This study examined the effect of the distance between the two electrodes on delayed onset muscle soreness during microcurrent therapy. [Methods] In this study 24 healthy women who hadn’t exercised regularly for six months were selected and randomly divided into two groups. Delayed onset muscle soreness (DOMS) was induced and experimental Group 1 were given microcurrent treatment with the electrodes attached at a close distance evaluated. Experimental Group 2 received the same treatment with the electrodes attached at a greater distance apart. Visual analogue scale pain and the RIII reflex were evaluated after inducing DOMS and after one day, two days, three days and four days of microcurrent treatment. [Results] The visual analogue scale and amplitude of RIII amplitude only showed significant differences with the length of time of the treatment. [Conclusion] This study found that difference of interelectrode distance has no influence on VAS pain and the RIII reflex of DOMS. Although there were no significant differences in RIII amplitude, we suspect that it may be influenced by current parameters such as frequency and intensity. PMID:24396208

  16. Effects of delayed treatment with nebracetam on neurotransmitters in brain regions after microsphere embolism in rats

    PubMed Central

    Takeo, Satoshi; Hayashi, Hideki; Miyake, Keiko; Takagi, Kaori; Tadokoro, Mina; Takagi, Norio; Oshikawa, Sayuri

    1997-01-01

    The effects of delayed treatment with nebracetam, a novel nootropic drug, on neurotransmitters of brain regions were examined in rats with microsphere embolism-induced cerebral ischaemia. Cerebral ischaemia was induced by administration of 900 microspheres (48 μm) into the internal carotid artery. The rats with stroke-like symptoms were treated p.o. with 30 mg kg−1 nebracetam twice daily. The levels of acetylcholine, dopamine, noradrenaline, 5-hydroxytryptamine (5-HT) and their metabolites in the cerebral cortex, striatum and hippocampus of animals with microsphere embolism were determined by high performance liquid chromatography (h.p.l.c.) on the 3rd and 7th days after the operation. Although the microsphere embolism induced significant changes in most of the neurotransmitters and some of their metabolites in the brain regions, the delayed treatment with nebracetam partially restored only the hippocampal 5-HT and the striatal dopamine metabolite contents on the 3rd day. The hippocampal in vivo 5-HT synthesis, but not the striatal dopamine synthesis, was attenuated in rats with microsphere embolism on the 3rd day, but was restored by treatment with nebracetam. In vivo striatal dopamine turnover rate of the rats with microsphere embolism was inhibited on the 3rd day irrespective of treatment with nebracetam. The present study provides evidence for a possible action of nebracetam on 5-HT metabolism in the ischaemic brain. PMID:9179389

  17. Effect of wettability on sessile drop freezing: when superhydrophobicity stimulates an extreme freezing delay.

    PubMed

    Boinovich, Ludmila; Emelyanenko, Alexandre M; Korolev, Vadim V; Pashinin, Andrei S

    2014-02-18

    An increasing number of studies directed at supercooling water droplets on surfaces with different wettabilities have appeared in recent years. This activity has been stimulated by the recognition that water supercooling phenomena can be effectively used to develop methods for protecting outdoor equipment and infrastructure elements against icing and snow accretion. In this article, we discuss the nucleation kinetics of supercooled sessile water droplets on hydrophilic, hydrophobic, and superhydrophobic surfaces under isothermal conditions at temperatures of -8, -10, and -15 °C and a saturated water vapor atmosphere. The statistics of nucleation events for the ensembles of freezing sessile droplets is completed by the detailed analysis of the contact angle temperature dependence and freezing of individual droplets in a saturated vapor atmosphere. We have demonstrated that the most essential freezing delay is characteristic of the superhydrophobic coating on aluminum, with the texture resistant to contact with ice and water. This delay can reach many hours at T = -8 °C and a few minutes at -23 °C. The observed behavior is analyzed on the basis of different nucleation mechanisms. The dissimilarity in the total nucleation rate, detected for two superhydrophobic substrates having the same apparent contact angle of the water drop but different resistivities of surface texture to the contact with water/ice, is associated with the contribution of heterogeneous nucleation on external centers located at the water droplet/air interface.

  18. Effects of Infection-Induced Migration Delays on the Epidemiology of Avian Influenza in Wild Mallard Populations

    PubMed Central

    Galsworthy, Stephen J.; ten Bosch, Quirine A.; Hoye, Bethany J.; Heesterbeek, Johan A. P.; Klaassen, Marcel; Klinkenberg, Don

    2011-01-01

    Wild waterfowl populations form a natural reservoir of Avian Influenza (AI) virus, and fears exist that these birds may contribute to an AI pandemic by spreading the virus along their migratory flyways. Observational studies suggest that individuals infected with AI virus may delay departure from migratory staging sites. Here, we explore the epidemiological dynamics of avian influenza virus in a migrating mallard (Anas platyrhynchos) population with a specific view to understanding the role of infection-induced migration delays on the spread of virus strains of differing transmissibility. We develop a host-pathogen model that combines the transmission dynamics of influenza with the migration, reproduction and mortality of the host bird species. Our modeling predicts that delayed migration of individuals influences both the timing and size of outbreaks of AI virus. We find that (1) delayed migration leads to a lower total number of cases of infection each year than in the absence of migration delay, (2) when the transmission rate of a strain is high, the outbreak starts at the staging sites at which birds arrive in the early part of the fall migration, (3) when the transmission rate is low, infection predominantly occurs later in the season, which is further delayed when there is a migration delay. As such, the rise of more virulent AI strains in waterfowl could lead to a higher prevalence of infection later in the year, which could change the exposure risk for farmed poultry. A sensitivity analysis shows the importance of generation time and loss of immunity for the effect of migration delays. Thus, we demonstrate, in contrast to many current transmission risk models solely using empirical information on bird movements to assess the potential for transmission, that a consideration of infection-induced delays is critical to understanding the dynamics of AI infection along the entire flyway. PMID:22028812

  19. Diverse Effects of a Seven-Year Experimental Grassland Fragmentation on Major Invertebrate Groups.

    PubMed

    Braschler, Brigitte; Baur, Bruno

    2016-01-01

    Habitat fragmentation is a major driver of biodiversity loss, but observed effects vary and may depend on the group examined. Time since fragmentation may explain some differences between taxonomical groups, as some species and thus species composition respond with a delay to changes in their environment. Impacts of drivers of global change may thus be underestimated in short-term studies. In our study we experimentally fragmented nutrient-poor dry calcareous grasslands and studied the response of species richness, individual density and species composition of various groups of invertebrates (gastropods, ants, ground beetles, rove beetles, orthoptera, spiders, woodlice) in 12 small (1.5 m * 1.5 m) and 12 large (4.5 m * 4.5 m) fragments and their corresponding control plots after 7 years. We further examined responses to fragmentation in relation to body size and habitat preferences. Responses to fragmentation varied between taxonomical groups. While spider species richness and individual density were lower in fragments, the opposite was true for an orthopteran species and woodlice. Species composition and β-diversity differed between fragments and control plots for some groups. However, the interaction treatment*plot size was rarely significant. Species with high occupancy rates in undisturbed control plots responded more negatively to the fragmentation, while species with large body size were relatively more abundant in fragments in some groups. No effect of the fragmentation was found for ants, which may have the longest lag times because of long-lived colonies. However, relationships between abundance and the species' preferences for environmental factors affected by edge effects indicate that ant diversity too may be affected in the longer-term. Our results show the importance of considering different groups in conservation management in times of widespread fragmentation of landscapes. While species richness may respond slowly, changes in abundance related to

  20. Diverse Effects of a Seven-Year Experimental Grassland Fragmentation on Major Invertebrate Groups

    PubMed Central

    Braschler, Brigitte; Baur, Bruno

    2016-01-01

    Habitat fragmentation is a major driver of biodiversity loss, but observed effects vary and may depend on the group examined. Time since fragmentation may explain some differences between taxonomical groups, as some species and thus species composition respond with a delay to changes in their environment. Impacts of drivers of global change may thus be underestimated in short-term studies. In our study we experimentally fragmented nutrient-poor dry calcareous grasslands and studied the response of species richness, individual density and species composition of various groups of invertebrates (gastropods, ants, ground beetles, rove beetles, orthoptera, spiders, woodlice) in 12 small (1.5 m * 1.5 m) and 12 large (4.5 m * 4.5 m) fragments and their corresponding control plots after 7 years. We further examined responses to fragmentation in relation to body size and habitat preferences. Responses to fragmentation varied between taxonomical groups. While spider species richness and individual density were lower in fragments, the opposite was true for an orthopteran species and woodlice. Species composition and β-diversity differed between fragments and control plots for some groups. However, the interaction treatment*plot size was rarely significant. Species with high occupancy rates in undisturbed control plots responded more negatively to the fragmentation, while species with large body size were relatively more abundant in fragments in some groups. No effect of the fragmentation was found for ants, which may have the longest lag times because of long-lived colonies. However, relationships between abundance and the species’ preferences for environmental factors affected by edge effects indicate that ant diversity too may be affected in the longer-term. Our results show the importance of considering different groups in conservation management in times of widespread fragmentation of landscapes. While species richness may respond slowly, changes in abundance related

  1. Diverse biological effects of electromagnetic-treated water.

    PubMed

    Yamabhai, Montarop; Chumseng, Suchintana; Yoohat, Kirana; Srila, Witsanu

    2014-07-01

    The effects of water treated with an electromagnetic field (EMF) were investigated on two biological systems, humans and plants. Purified de-ionised water was treated by (1) boiling, (2) exposure to microwave radiation, and (3) low frequency electromagnetic oscillation molecular resonance effect technology (MRET), before being used to prepare media for culturing human peripheral blood mononuclear cells (PBMC) from three healthy females. Our results indicated that PBMC culture in MRET-activated medium showed significantly less oxidative metabolism when compared to media prepared from other types of water. As for the effects on soybean, our results indicated that both MRET- and microwave-treated water greatly enhanced the length of the root. These results suggested that electromagnetic-treated water can have diverse biological effects on both animal and plant cells. Since these effects are related to the 'Memory of Water', hypothesis which has been suggested as an explanation of the action of high homeopathic dilutions, our finding warrant a further investigation on the mechanisms of various types of physically conditioned water on specific cellular activities.

  2. Diverse Effects, Complex Causes: Children Use Information About Machines' Functional Diversity to Infer Internal Complexity.

    PubMed

    Ahl, Richard E; Keil, Frank C

    2017-05-01

    Four studies explored the abilities of 80 adults and 180 children (4-9 years), from predominantly middle-class families in the Northeastern United States, to use information about machines' observable functional capacities to infer their internal, "hidden" mechanistic complexity. Children as young as 4 and 5 years old used machines' numbers of functions as indications of complexity and matched machines performing more functions with more complex "insides" (Study 1). However, only older children (6 and older) and adults used machines' functional diversity alone as an indication of complexity (Studies 2-4). The ability to use functional diversity as a complexity cue therefore emerges during the early school years, well before the use of diversity in most categorical induction tasks. © 2016 The Authors. Child Development © 2016 Society for Research in Child Development, Inc.

  3. Disentangling the roles of diversity resistance and priority effects in community assembly.

    PubMed

    Viana, Duarte S; Cid, Bertha; Figuerola, Jordi; Santamaría, Luis

    2016-11-01

    The assembly of many biological communities is constrained by the resistance exerted by resident species to immigration (biotic resistance). Two important mechanisms contribute to the generation of biotic resistance: diversity resistance and priority effects. These mechanisms have been explored through theoretical models and laboratory experiments, but the importance of their interplay in the assembly of natural communities remains untested. We used a mesocosm experiment with communities of aquatic plants and zooplankton assembled from natural propagule banks to test whether and how diversity resistance, mediated by the diversity of the resident community, and priority effects, mediated by the timing of immigrants' arrival, affect the establishment of immigrant species and community diversity. In plant communities, immigration success decreased with increasing resident-species richness (diversity resistance) and arrival time (priority effects). Further, diversity resistance was stronger in communities colonized later in the season, indicating that these mechanisms interacted to reinforce biotic resistance. This interaction ultimately determined species richness and beta-diversity in plant communities. For zooplankton, in contrast, neither the diversity of resident communities nor the time of arrival affected the establishment of immigrant species. In these communities, beta-diversity was explained by species sorting, namely biotic effects mediated by plant assemblages. Our results show that the progressive buildup of communities generates an interaction between diversity resistance and priority effects that eventually determines community diversity, unless species sorting mediated by environmental filtering supersedes the effect of biotic resistance. Therefore, disentangling the mechanisms underlying biotic resistance contributes to understand how species diversity is ultimately determined.

  4. Malaria epidemiology and economics: the effect of delayed immune acquisition on the cost-effectiveness of insecticide-treated bednets.

    PubMed Central

    Guyatt, H L; Snow, R W; Evans, D B

    1999-01-01

    An understanding of the epidemiology of a disease is central in evaluating the health impact and cost-effectiveness of control interventions. The epidemiology of life-threatening malaria is receiving renewed interest, with concerns that the implementation of preventive measures such as insecticide-treated bednets (ITNs) while protecting young children might in fact increase the risks of mortality and morbidity in older ages by delaying the acquisition of functional immunity. This paper aims to illustrate how a combined approach of epidemiology and economics can be used to (i) explore the long-term impact of changes in epidemiological profiles, and (ii) identify those variables that are critical in determining whether an intervention will be an efficient use of resources. The key parameters for determining effectiveness are the protective efficacy of ITNs (reduction in all-cause mortality), the malaria attributable mortality and the increased malaria-specific mortality risk due to delays in the acquisition of functional immunity. In particular, the analysis demonstrates that delayed immune acquisition is not a problem per se, but that the critical issue is whether it occurs immediately following the implementation of an ITN programme or whether it builds up slowly over time. In the 'worst case' scenario where ITNs immediately increase malaria-specific mortality due to reduced immunity, the intervention might actually cost lives. In other words, it might be better to not use ITNs. On the other hand, if reduced immunity takes two years to develop, ITNs would still fall into the category of excellent value for money compared to other health interventions, saving a year of life (YLL) at a cost of between US$25-30. These types of calculations are important in identifying the parameters which field researchers should be seeking to measure to address the important question of the net impact of delaying the acquisition of immunity through preventive control measures. PMID

  5. Neutralizing nanobodies targeting diverse chemokines effectively inhibit chemokine function.

    PubMed

    Blanchetot, Christophe; Verzijl, Dennis; Mujić-Delić, Azra; Bosch, Leontien; Rem, Louise; Leurs, Rob; Verrips, C Theo; Saunders, Michael; de Haard, Hans; Smit, Martine J

    2013-08-30

    Chemokine receptors and their ligands play a prominent role in immune regulation but many have also been implicated in inflammatory diseases such as multiple sclerosis, rheumatoid arthritis, allograft rejection after transplantation, and also in cancer metastasis. Most approaches to therapeutically target the chemokine system involve targeting of chemokine receptors with low molecular weight antagonists. Here we describe the selection and characterization of an unprecedented large and diverse panel of neutralizing Nanobodies (single domain camelid antibodies fragment) directed against several chemokines. We show that the Nanobodies directed against CCL2 (MCP-1), CCL5 (RANTES), CXCL11 (I-TAC), and CXCL12 (SDF-1α) bind the chemokines with high affinity (at nanomolar concentration), thereby blocking receptor binding, inhibiting chemokine-induced receptor activation as well as chemotaxis. Together, we show that neutralizing Nanobodies can be selected efficiently for effective and specific therapeutic treatment against a wide range of immune and inflammatory diseases.

  6. Effectiveness of Constant Time Delay on Teaching Snack and Drink Preparation Skills to Children with Mental Retardation

    ERIC Educational Resources Information Center

    Bozkurt, Funda; Gursel, Oguz

    2005-01-01

    A multiple probe design with probe conditions across behaviors was used to evaluate effectiveness of constant time delay on teaching snack and drink preparation skills to children with mental retardation. In addition, generalization effects across settings, time, and materials, and maintenance effects were examined. Three students between the ages…

  7. ERP correlates of the incidental retrieval of emotional information: effects of study-test delay

    PubMed Central

    Jaeger, Antonio; Johnson, Jeffrey D.; Corona, Maria; Rugg, Michael D.

    2009-01-01

    Prior studies indicate that, in tests of recognition memory, ERPs elicited by correctly recognized test items differ according to whether the items were encoded in an emotionally arousing or an emotionally neutral study context. These prior studies employed only a relatively brief (ca. 10 min) retention interval, however. The present study contrasted the ERP correlates of incidental emotional retrieval as a function of study-test delay. Pictures of emotionally neutral objects were encoded in association with either emotionally negative or emotionally neutral scenes. In a repeated measures design (N=19), half of the objects were subjected to a recognition memory test 10 min after completion of the study phase, whereas the remainder were tested 24 hrs later. After the short delay, ERPs elicited by objects paired with emotional vs. neutral backgrounds differed from around 200 ms post-stimulus, the objects paired with the emotional scenes eliciting the more positive-going waveforms. After 24 hrs, differences between the ERPs elicited by the two classes of object were still apparent from around 200 ms post-stimulus. Strikingly, these effects differed from those obtained 10 min after study in both their polarity and scalp distribution. The early onset of these ERP effects suggests that they may reflect a form of memory independent of the conscious recollection of the associated study contexts. The qualitative differences in the effects at the two retention intervals raises the possibility that the encoded objects were subjected to consolidation processes that differed according to the emotional attributes of their study contexts. PMID:19285970

  8. Effects of β-adrenoceptor stimulation on delayed rectifier K+ currents in canine ventricular cardiomyocytes

    PubMed Central

    Harmati, G; Bányász, T; Bárándi, L; Szentandrássy, N; Horváth, B; Szabó, G; Szentmiklósi, JA; Szénási, G; Nánási, PP; Magyar, J

    2011-01-01

    BACKGROUND AND PURPOSE While the slow delayed rectifier K+ current (IKs) is known to be enhanced by the stimulation of β-adrenoceptors in several mammalian species, phosphorylation-dependent regulation of the rapid delayed rectifier K+ current (IKr) is controversial. EXPERIMENTAL APPROACH In the present study, therefore, the effect of isoprenaline (ISO), activators and inhibitors of the protein kinase A (PKA) pathway on IKr and IKs was studied in canine ventricular myocytes using the whole cell patch clamp technique. KEY RESULTS IKr was significantly increased (by 30–50%) following superfusion with ISO, forskolin or intracellular application of PKA activator cAMP analogues (cAMP, 8-Br-cAMP, 6-Bnz-cAMP). Inhibition of PKA by Rp-8-Br-cAMP had no effect on baseline IKr. The stimulating effect of ISO on IKr was completely inhibited by selective β1-adrenoceptor antagonists (metoprolol and CGP-20712A), by the PKA inhibitor Rp-8-Br-cAMP and by the PKA activator cAMP analogues, but not by the EPAC activator 8-pCPT-2'-O-Me-cAMP. In comparison, IKs was increased threefold by the activation of PKA (by ISO or 8-Br-cAMP), and strongly reduced by the PKA inhibitor Rp-8-Br-cAMP. The ISO-induced enhancement of IKs was decreased by Rp-8-Br-cAMP and completely inhibited by 8-Br-cAMP. CONCLUSIONS AND IMPLICATIONS The results indicate that the stimulation of β1-adrenoceptors increases IKr, similar to IKs, via the activation of PKA in canine ventricular cells. PMID:20973780

  9. Nicotine effects on immediate and delayed verbal memory after substance use detoxification.

    PubMed

    Gilbertson, Rebecca; Boissoneault, Jeff; Prather, Robert; Nixon, Sara Jo

    2011-07-01

    Decrements in verbal memory are commonly reported by detoxified treatment-seeking individuals. Although acute nicotine has been shown to improve attentional performance, its effects on verbal memory in substance abusers have not been addressed. Treatment-seeking alcohol-dependent (ALCs, n = 29; 14 male), illicit-stimulant-dependent (predominantly cocaine; STIMs, n = 25; 15 male), and alcohol- and illicit-stimulant-dependent (ALC/STIMs, n = 50; 35 male) participants with comorbid nicotine dependence were studied. Subjects had been abstinent from their drugs of choice for 41 (±18) days and were in short-term abstinence from tobacco (∼8-10 hours). Subjects received double-blind administration of either transdermal nicotine (high dose: 21/14 mg for men and women, respectively, or low dose: 7 mg) or placebo. The Logical Memory (LM) subtest from the Wechsler Memory Scale-Revised (WMS-R) was used to assess immediate and delayed verbal memory recall. Results indicated that STIMs receiving the high dose of nicotine recalled more words at immediate recall than STIMs who received placebo. Trend level differences were also noted at delayed recall between STIM nicotine and placebo doses. Nicotine failed to impact either recall in alcoholic subgroups. Although not the primary focus, results also revealed differences in the forgetting rates between the groups with the ALC/STIMs demonstrating the steepest forgetting slope. In summary, this study suggests that nicotine effects may be differentially experienced by substance-using subgroups; that nicotine may have a direct effect on memory; and that in considering neurocognitive processes (e.g., encoding vs. retrieval), underlying endpoint indicators (e.g., correct recall) may be critical in predicting outcomes.

  10. Nicotine Effects on Immediate and Delayed Verbal Memory After Substance Use Detoxification

    PubMed Central

    Gilbertson, Rebecca; Boissoneault, Jeff; Prather, Robert; Nixon, Sara Jo

    2010-01-01

    Decrements in verbal memory are commonly reported by detoxified treatment-seeking individuals. Although acute nicotine has been shown to improve attentional performance, its effects on verbal memory in substance abusers have not been addressed. Treatment-seeking alcohol dependent (ALCS N=29; 14 male), illicit stimulant (predominantly cocaine) dependent (STIMS N = 25; 15 male) and alcohol and illicit stimulant dependent (ALC/STIMS N = 50; 35 male) participants with co-morbid nicotine dependence were studied. Subjects had been abstinent from their drugs of choice for 41(±18) days and were in short-term abstinence from tobacco (~8–10 hours). Subjects received double-blind administration of either transdermal nicotine (High dose: 21/14 mg for men and women, respectively or Low dose: 7 mg) or placebo. The Logical Memory (LM) subtest from the Wechsler Memory Scale -Revised (WMS-R) was used to assess immediate and delayed verbal memory recall. Results indicated that STIMS receiving the high dose of nicotine recalled more words at immediate recall than STIMS who received placebo. Trend level differences were also noted at delayed recall between STIM nicotine and placebo doses. Nicotine failed to impact either recall in alcoholic subgroups. Although not the primary focus, results also revealed differences in the forgetting rates between the groups with the ALC/STIMS demonstrating the steepest forgetting slope. In summary, this study suggests that nicotine effects may be differentially experienced by substance using subgroups; that nicotine may have a direct effect on memory and, that considering neurocognitive processes (e.g., encoding vs. retrieval) underlying endpoint indicators (e.g. correct recall) may be critical in predicting outcomes. PMID:21526444

  11. Effect of Pre-Fixation Delay and Freezing on Mink Testicular Endpoints for Environmental Research

    PubMed Central

    Spörndly-Nees, Ellinor; Ekstedt, Elisabeth; Magnusson, Ulf; Fakhrzadeh, Azadeh; Luengo Hendriks, Cris L.; Holm, Lena

    2015-01-01

    There is growing interest in using wild animals to monitor the real-life cocktail effect of environmental chemicals on male reproduction. However, practical difficulties, such as long distances to the laboratory, generally prolong the time between euthanisation and specimen handling. For instance, tissue fixation is often performed on frozen material or on material where deterioration has started, which may affect tissue morphology. This study examined the effect of pre-fixation delay and freezing on mink testicular endpoints in order to determine robust endpoints in suboptimally handled specimens. Sexually mature farmed mink (n=30) selected at culling were divided into six groups and subjected to different time intervals between euthanisation and fixation or freezing: 0 hours (fixed immediately post mortem), 6 hours, 18 hours, 30 hours, 42 hours, or frozen 6 hours post mortem and thawed overnight. Unaffected endpoints when pre-fixation storage was extended to 30 hours included: area and diameter of the seminiferous tubules, length and weight of the testes, and acrosomes marked with Gata-4. Epithelial height, Sertoli cells marked with Gata-4 and cell morphology were affected endpoints after 6 hours of storage. Freezing the tissue prior to fixation severely altered cell morphology and reduced testicular weight, tubular diameter and area. Morphological changes seen after 6 hours included shredded germ cells and excess cytoplasm in seminiferous tubular lumen, chromatin rearrangements and increased germ cell death. Extended delay before fixation and freezing affected many endpoints in the mink testicular tissue. Some of these endpoints may mimic chemically induced effects, which is important to consider when evaluating specimens from wild animals for environmental toxicity. PMID:25933113

  12. Effectiveness of delayed activated charcoal administration in simulated paracetamol (acetaminophen) overdose

    PubMed Central

    Yeates, P J A; Thomas, S H L

    2000-01-01

    Aims Oral activated charcoal is used to treat drug overdose and is effective at reducing drug absorption when administered within 1 h of drug ingestion. There are fewer data on efficacy when the delay is longer, as is the case in most drug overdoses. This study investigated the efficacy of activated charcoal at preventing paracetamol (acetaminophen) absorption after simulated overdose when administration was delayed between 1 and 4 h. Methods An open randomized-order four-way crossover study was performed in healthy volunteers comparing the effect of activated charcoal 50 g on the absorption of 3 g paracetamol tablets when administered after an interval of 1, 2 or 4 h or not at all. Plasma paracetamol concentrations were measured over 9 h after paracetamol ingestion using h.p.l.c. and areas under the curve between 4 and 9 h (AUC(4,9 h)) calculated as a measure of paracetamol absorption. Results Activated charcoal significantly reduced paracetamol AUC(4,9 h) when administered after 1 h (mean reduction 56%; 95% Confidence intervals 34, 78; P < 0.002) or 2 h (22%; 6, 39; P < 0.03) but not after 4 h (8%; −8, 24). When administered after 1 h activated charcoal reduced individual plasma paracetamol concentrations significantly at all times between 4 and 9 h after paracetamol administration. Administration at 2 or 4 h had no significant effect. Conclusions These results in healthy volunteers cannot be extrapolated directly to poisoned patients. However, they provide no evidence of efficacy for activated charcoal when administered after an interval of more than 2 h. PMID:10606832

  13. Cognitive Control Modulates Effects of Episodic Simulation on Delay Discounting in Aging.

    PubMed

    Sasse, Laura K; Peters, Jan; Brassen, Stefanie

    2017-01-01

    Enhancing prospective thinking by tagging the future with specific episodic events has been shown to reduce delay discounting in young age ("tag-effect"). So far, it is unclear whether such beneficial effect extends to old adulthood. Since the general ability of future thinking and cognitive control are crucial modulators of temporal discounting in young age, potential age-related decline in these functions might impact on the effect. We focused on this issue by combining functional magnetic resonance imaging (fMRI) with an established intertemporal choice task including episodic "tags" in healthy older participants. Future thinking ability was assessed using autobiographical interviews for future event simulations and a visual search task was applied to assess participants' cognitive control ability. In contrast to previous data in young adults, the group of older participants did not benefit from tagging the future with episodic events. Older participants' cognitive control function was directly associated with discounting rates in the episodic conditions: the less the older adults were able to focus their attention the less they benefited from the inclusion of episodic events. Consistent with this, imaging results revealed that: (a) subjective value (SV) signals in the hippocampus and the anterior cingulate cortex (ACC) as well as; (b) hippocampal-striatal coupling during the episodic condition were positively related to participants' control capacity. Our findings highlight the critical role of executive functioning for the simultaneous integration of episodic information with future value computation in aging. Boosting delay gratification by including episodic tags might hence be limited in older individuals with pronounced decline in distraction control.

  14. Reinforcer magnitude affects delay discounting and influences effects of d-amphetamine in rats.

    PubMed

    Krebs, Christopher A; Reilly, William J; Anderson, Karen G

    2016-09-01

    Impulsive choice in humans can be altered by changing reinforcer magnitude; however, this effect has not been found in rats. Current levels of impulsive choice can also influence effects of d-amphetamine. This study used a within-subject assessment to determine if impulsive choice is sensitive to changes in reinforcer magnitude, and whether effects of d-amphetamine are related to current levels of impulsive choice. A discounting procedure in which choice was for a smaller reinforcer available immediately or a larger reinforcer available after a delay that increased within session was used. Reinforcer magnitude was manipulated between conditions and impulsive choice was quantified using area under the curve (AUC). In the Smaller-Magnitude (SM) Condition, choice was between one food pellet and three food pellets. In the Larger-Magnitude (LM) Condition, choice was between two food pellets and six food pellets. Impulsive choice was greater in the SM Condition compared to the LM Condition. Further, effects of d-amphetamine (0.1-1.8mg/kg) were related to differences in impulsive choice. d-Amphetamine increased impulsive choice in the LM Condition, but had no effect on impulsive choice in the SM Condition. Overall, these results show that impulsive choice in rats is sensitive to changes in reinforcer magnitude, and that effects of d-amphetamine are influenced by current levels of impulsive choice.

  15. Polarization and probe delay effect on degenerate four wave mixing of pyrazine

    NASA Astrophysics Data System (ADS)

    Li, Hongzhi; Kong, Wei

    1997-09-01

    Degenerate four wave mixing (DFWM) in supersonically cooled pyrazine was investigated using different polarization combinations of the three input beams. A common feature of these spectra was the strong Q branch, stronger than the corresponding spectra for a single photon process. The ratios for all the rotational branches demonstrated strong dependence on the polarization combination. The YYXX combination showed similar intensities for the P and R branches, while the YXYX combination had a much stronger R branch. The Q branch, relative to the P branch, was the strongest for the YYYY combination. All experiments probed for the same electronic transition with the same Hönl-London factor; therefore the variation in the rotational branching ratios was solely an effect of the polarization combinations. This polarization dependence of DFWM can be traced back to the selectivity in the magnetic quantum number for this multiphoton process. Based on the theoretical framework by Williams et al. [J. Chem. Phys. 101, 1072 (1994)], these spectra were simulated successfully. The calculations and analysis of the experimental conditions revealed that among the twelve gratings included in the original theory, only three of them had observable contributions to the experimental spectra, i.e., the gratings formed through the ground-state molecules via the two forward beams. The other nine gratings either were washed out or decayed in the collision free environment (supersonic expansion) under an excitation pulse of 7 ns. This argument was further confirmed by another experiment using a time delay between the backward probe beam and the two forward beams. The spectra recorded with a 15 ns delay in the probe beam (longer than the pulse duration of each input beam) were similar to those without delays. These results implied that (1) the backward beam did not participate in the grating formation process even when it arrived at the interaction region simultaneously with the two forward

  16. Synchronization transitions on small-world neuronal networks: Effects of information transmission delay and rewiring probability

    NASA Astrophysics Data System (ADS)

    Wang, Qingyun; Duan, Zhisheng; Perc, Matjaž; Chen, Guanrong

    2008-09-01

    Synchronization transitions are investigated in small-world neuronal networks that are locally modeled by the Rulkov map with additive spatiotemporal noise. In particular, we investigate the impact of different information transmission delays and rewiring probability. We show that short delays induce zigzag fronts of excitations, whereas intermediate delays can further detriment synchrony in the network due to a dynamic clustering anti-phase synchronization transition. Detailed investigations reveal, however, that for longer delay lengths the synchrony of excitations in the network can again be enhanced due to the emergence of in-phase synchronization. In addition, we show that an appropriate small-world topology can restore synchronized behavior provided information transmission delays are either short or long. On the other hand, within the intermediate delay region, which is characterized by anti-phase synchronization and clustering, differences in the network topology do not notably affect the synchrony of neuronal activity.

  17. Effects of fatigue and recovery on electromechanical delay during isokinetic muscle actions.

    PubMed

    Smith, Cory M; Housh, Terry J; Hill, Ethan C; Keller, Joshua L; Johnson, Glen O; Schmidt, Richard J

    2017-09-21

    To examine muscle-specific differences and the effects of fatigue and recovery on electromechanical delay (EMD) during maximal isokinetic muscle actions. Thirteen men performed maximal isokinetic knee extension muscle actions at 60° s(-1), pretest, posttest, and after 5 min of recovery from 25 maximal isokinetic knee extensions. The onsets of the electromyographic, mechanomyographic, and force signals were used to identify EMD measures from the vastus lateralis (VL), vastus medialis (VM), and rectus femoris (RF). There were posttest increases in all EMD measures for all muscles that returned to pretest levels after 5 min of recovery. There were, however, no differences in EMD measures between the VL and VM. All EMD values from the RF were greater than the VL and VM. These findings suggested muscle-specific differences in EMD and that excitation-contraction coupling failure and increased compliance of the series elastic component occurred posttest, but subsided after 5 min of recovery.

  18. Effect of artificial acid rain and SO2 on characteristics of delayed light emission.

    PubMed

    Wang, Chenglong; Xing, Da; Zeng, Lizhang; Ding, Chunfeng; Chen, Qun

    2005-01-01

    The structure and function of chloroplast in plant leaves can be affected by acid rain and air pollution. The photosystem II in a plant is considered the primary site where light-induced delayed light emission (DLE) is produced. With the lamina of zijinghua (Bauhinia variegata L.) and soybean (Glycine max (L.) Merr.) as testing models, we studied the effects of artificial acid rain and SO2 on characteristics of DLE by using a home-made weak luminescence detection system. The results show that the changes in DLE intensity of green plants can reflect the changes in chloroplast intactness and function. With proper calibration, DLE may provide an alternative means of evaluating environmental acid stress on plants. The changes in DLE intensity may provide a new approach for the detection of environmental pollution and its impact on the ecosystem.

  19. The effect of enteric-coated, delayed-release peppermint oil on irritable bowel syndrome.

    PubMed

    Merat, Shahin; Khalili, Shadi; Mostajabi, Pardise; Ghorbani, Anahita; Ansari, Reza; Malekzadeh, Reza

    2010-05-01

    Herbal remedies, particularly peppermint, have been reported to be helpful in controlling symptoms of irritable bowel syndrome (IBS). We conducted a randomized double-blind placebo-controlled study on 90 outpatients with IBS. Subjects took one capsule of enteric-coated, delayed-release peppermint oil (Colpermin) or placebo three times daily for 8 weeks. We visited patients after the first, fourth, and eighth weeks and evaluated their symptoms and quality of life. The number of subjects free from abdominal pain or discomfort changed from 0 at week 0 to 14 at week 8 in the Colpermin group and from 0 to 6 in controls (P < 0.001). The severity of abdominal pain was also reduced significantly in the Colpermin group as compared to controls. Furthermore, Colpermin significantly improved the quality of life. There was no significant adverse reaction. Colpermin is effective and safe as a therapeutic agent in patients with IBS suffering from abdominal pain or discomfort.

  20. Individual benefits of nestling begging: experimental evidence for an immediate effect, but no evidence for a delayed effect.

    PubMed

    Lessells, C Kate M; Riebel, Katharina; Draganoiu, Tudor Ion

    2011-06-23

    The evolutionary stability of honest signalling by offspring is thought to require that begging displays be costly, so the costs and benefits of begging--and whether they are experienced individually or by the whole brood--are crucial to understanding the evolution of begging behaviour. Begging is known to have immediate individual benefits (parents distribute more food to intensely begging individuals) and delayed brood benefits (parents increase provisioning rate to the brood), but the possibility of delayed individual benefits (previous begging affects the current distribution of food) has rarely, if ever, been researched. We did this using playback of great tit Parus major chick begging and a control sound from either side of the nest. Male parents fed chicks close to the speaker more when great tit chick begging, but not other stimuli, was played back. In contrast, there was no effect of playback at the previous visit on the chicks that male parents fed. We have thus demonstrated an immediate individual benefit to begging, but found no evidence of a delayed individual benefit in this species.

  1. It's Your Game: Keep It Real: delaying sexual behavior with an effective middle school program.

    PubMed

    Tortolero, Susan R; Markham, Christine M; Peskin, Melissa Fleschler; Shegog, Ross; Addy, Robert C; Escobar-Chaves, S Liliana; Baumler, Elizabeth R

    2010-02-01

    This study tested the effects of a theory-based, middle-school human immunodeficiency virus, STI, and pregnancy prevention program, It's Your Game: Keep it Real (IYG), in delaying sexual behavior. We hypothesized that the IYG intervention would decrease the number of adolescents who initiated sexual activity by the ninth grade compared with those in the comparison schools. The target population consisted of English-speaking middle school students from a large, urban, predominantly African-American and Hispanic school district in Southeast Texas. Ten middle schools were randomly assigned either to receive the intervention or to the comparison condition. Seventh-grade students were recruited and followed through ninth grade. The IYG intervention comprises 12 seventh-grade and 12 eighth-grade lessons that integrate group-based classroom activities with computer-based instruction and personal journaling. Ninth-grade follow-up surveys were completed by 907 students (92% of the defined cohort). The primary hypothesis tested was that the intervention would decrease the number of adolescents who initiated sexual activity by the ninth grade compared with those in the comparison schools. Almost one-third (29.9%, n=509) of the students in the comparison condition initiated sex by ninth grade compared with almost one-quarter (23.4%, n=308) of those in the intervention condition. After adjusting for covariates, students in the comparison condition were 1.29 times more likely to initiate sex by the ninth grade than those in the intervention condition. A theory-driven, multi-component, curriculum-based intervention can delay sexual initiation up to 24 months; can have impact on specific types of sexual behavior such as initiation of oral and anal sex; and may be especially effective with females. Future research must explore the generalizabilty of these results. Copyright 2010 Society for Adolescent Medicine. Published by Elsevier Inc. All rights reserved.

  2. Acute effects of ginger extract on biochemical and functional symptoms of delayed onset muscle soreness

    PubMed Central

    Hoseinzadeh, Khadijeh; Daryanoosh, Farhad; Baghdasar, Parvin Javad; Alizadeh, Hamid

    2015-01-01

    Background: Inflammation and pain induced by delayed onset muscle soreness (DOMS) as a result of eccentric exercise (EE) or unaccustomed activity cause some difficulties in exercise for athletes. The purpose of this study was to survey the effect of ginger extract on biochemical and functional symptom of delayed onset muscle soreness. Methods: In a quasi-experimental study, 36 healthy female subjects, who were recruited by intra dormitory calls, randomly divided into 3 groups, including: ginger intake 1 hour before exercise (GIBE), ginger intake immediately after exercise (GIAE) and placebo group (PL). Subjects consumed capsules contain 60 mg of ginger extract (equivalent of 2 g dried ginger powder) or placebo before and after exercise. The exercise protocol consisted of a 20 minute step test using a 46cm step at a rate of 15 steps per minute. The blood samples were taken before, 1, 24 and 48 hour after exercise to assay creatine kinase (CK) and interleukin-6 (IL-6). Muscle pain scores, isometric strength and circumference of thigh muscle, and hip range of motion were recorded at mentioned times. The analysis of variance (ANOVA) with repeated measure was used to determine the differences between groups. Results: The results showed a significant reduction of pain in GIBE compared to GIAE after 24 and 48h of EE and GIAE compared to PL (p<0.05). IL-6 changed significantly in GIBE compared to PL (p<0.05) after 1, 24, and 48h after EE. The other factors didn’t change meaningfully. Conclusion: The finding of this study suggests that 2 grams of ginger may have anti-inflammation and analgesic effect on DOMS. PMID:26793652

  3. Cognitive Control Modulates Effects of Episodic Simulation on Delay Discounting in Aging

    PubMed Central

    Sasse, Laura K.; Peters, Jan; Brassen, Stefanie

    2017-01-01

    Enhancing prospective thinking by tagging the future with specific episodic events has been shown to reduce delay discounting in young age (“tag-effect”). So far, it is unclear whether such beneficial effect extends to old adulthood. Since the general ability of future thinking and cognitive control are crucial modulators of temporal discounting in young age, potential age-related decline in these functions might impact on the effect. We focused on this issue by combining functional magnetic resonance imaging (fMRI) with an established intertemporal choice task including episodic “tags” in healthy older participants. Future thinking ability was assessed using autobiographical interviews for future event simulations and a visual search task was applied to assess participants’ cognitive control ability. In contrast to previous data in young adults, the group of older participants did not benefit from tagging the future with episodic events. Older participants’ cognitive control function was directly associated with discounting rates in the episodic conditions: the less the older adults were able to focus their attention the less they benefited from the inclusion of episodic events. Consistent with this, imaging results revealed that: (a) subjective value (SV) signals in the hippocampus and the anterior cingulate cortex (ACC) as well as; (b) hippocampal-striatal coupling during the episodic condition were positively related to participants’ control capacity. Our findings highlight the critical role of executive functioning for the simultaneous integration of episodic information with future value computation in aging. Boosting delay gratification by including episodic tags might hence be limited in older individuals with pronounced decline in distraction control. PMID:28352226

  4. Presumed fair: ironic effects of organizational diversity structures.

    PubMed

    Kaiser, Cheryl R; Major, Brenda; Jurcevic, Ines; Dover, Tessa L; Brady, Laura M; Shapiro, Jenessa R

    2013-03-01

    This research tests the hypothesis that the presence (vs. absence) of organizational diversity structures causes high-status group members (Whites, men) to perceive organizations with diversity structures as procedurally fairer environments for underrepresented groups (racial minorities, women), even when it is clear that underrepresented groups have been unfairly disadvantaged within these organizations. Furthermore, this illusory sense of fairness derived from the mere presence of diversity structures causes high-status group members to legitimize the status quo by becoming less sensitive to discrimination targeted at underrepresented groups and reacting more harshly toward underrepresented group members who claim discrimination. Six experiments support these hypotheses in designs using 4 types of diversity structures (diversity policies, diversity training, diversity awards, idiosyncratically generated diversity structures from participants' own organizations) among 2 high-status groups in tests involving several types of discrimination (discriminatory promotion practices, adverse impact in hiring, wage discrimination). Implications of these experiments for organizational diversity and employment discrimination law are discussed. PsycINFO Database Record (c) 2013 APA, all rights reserved

  5. Plant diversity effects on leaching of nitrate, ammonium, and dissolved organic nitrogen from an experimental grassland

    NASA Astrophysics Data System (ADS)

    Leimer, Sophia; Oelmann, Yvonne; Wirth, Christian; Wilcke, Wolfgang

    2014-05-01

    Leaching of nitrogen (N) from soil represents a resource loss and, in particular leaching of nitrate, can threaten drinking water quality. As plant diversity leads to a more exhaustive resource use, we investigated the effects of plant species richness, functional group richness, and the presence of specific functional groups on nitrate, ammonium, dissolved organic N (DON), and total dissolved N (TDN) leaching from an experimental grassland in the first 4 years after conversion from fertilized arable land to unfertilized grassland. The experiment is located in Jena, Germany, and consists of 82 plots with 1, 2, 4, 8, 16, or 60 plant species and 1-4 functional groups (legumes, grasses, non-leguminous tall herbs, non-leguminous small herbs). Nitrate, ammonium, and TDN concentrations in soil solution in the 0-0.3 m soil layer were measured every second week during 4 years on 62 plots and DON concentrations were calculated as difference between TDN and inorganic N. Missing concentrations in soil solution were estimated using a Bayesian statistical model. Downward water fluxes (DF) per plot from the 0-0.3 m soil layer were simulated in weekly resolution with a water balance model in connection with a Bayesian model for simulating missing soil water content measurements. To obtain annual nitrate, ammonium, and DON leaching from the 0-0.3 m soil layer per plot, we multiplied the respective concentrations in soil solution with DF and aggregated the data to annual sums. TDN leaching resulted from summation of nitrate, ammonium, and DON leaching. DON leaching contributed most to TDN leaching, particularly in plots without legumes. Dissolved inorganic N leaching in this grassland was dominated by nitrate. The amount of annual ammonium leaching was small and little influenced by plant diversity. Species richness affected DON leaching only in the fourth and last investigated year, possibly because of a delayed soil biota effect that increased microbial transformation of organic

  6. The effectiveness of multimedia visual perceptual training groups for the preschool children with developmental delay.

    PubMed

    Chen, Yi-Nan; Lin, Chin-Kai; Wei, Ta-Sen; Liu, Chi-Hsin; Wuang, Yee-Pay

    2013-12-01

    This study compared the effectiveness of three approaches to improving visual perception among preschool children 4-6 years old with developmental delays: multimedia visual perceptual group training, multimedia visual perceptual individual training, and paper visual perceptual group training. A control group received no special training. This study employed a pretest-posttest control group of true experimental design. A total of 64 children 4-6 years old with developmental delays were randomized into four groups: (1) multimedia visual perceptual group training (15 subjects); (2) multimedia visual perceptual individual training group (15 subjects); paper visual perceptual group training (19 subjects); and (4) a control group (15 subjects) with no visual perceptual training. Forty minute training sessions were conducted once a week for 14 weeks. The Test of Visual Perception Skills, third edition, was used to evaluate the effectiveness of the intervention. Paired-samples t-test showed significant differences pre- and post-test among the three groups, but no significant difference was found between the pre-test and post-test scores among the control group. ANOVA results showed significant differences in improvement levels among the four study groups. Scheffe post hoc test results showed significant differences between: group 1 and group 2; group 1 and group 3; group 1 and the control group; and group 2 and the control group. No significant differences were reported between group 2 and group 3, and group 3 and the control group. The results showed all three therapeutic programs produced significant differences between pretest and posttest scores. The training effect on the multimedia visual perceptual group program and the individual program was greater than the developmental effect Both the multimedia visual perceptual group training program and the multimedia visual perceptual individual training program produced significant effects on visual perception. The

  7. Medicare Program; Advancing Care Coordination Through Episode Payment Models (EPMs); Cardiac Rehabilitation Incentive Payment Model; and Changes to the Comprehensive Care for Joint Replacement Model (CJR); Delay of Effective Date. Final rule; delay of effective date.

    PubMed

    2017-05-19

    This final rule finalizes May 20, 2017 as the effective date of the final rule titled "Advancing Care Coordination Through Episode Payment Models (EPMs); Cardiac Rehabilitation Incentive Payment Model; and Changes to the Comprehensive Care for Joint Replacement Model (CJR)" originally published in the January 3, 2017 Federal Register. This final rule also finalizes a delay of the applicability date of the regulations at 42 CFR part 512 from July 1, 2017 to January 1, 2018 and delays the effective date of the specific CJR regulations listed in the DATES section from July 1, 2017 to January 1, 2018.

  8. Diversity spurs diversification in ecological communities

    NASA Astrophysics Data System (ADS)

    Calcagno, Vincent; Jarne, Philippe; Loreau, Michel; Mouquet, Nicolas; David, Patrice

    2017-06-01

    Diversity is a fundamental, yet threatened, property of ecological systems. The idea that diversity can itself favour diversification, in an autocatalytic process, is very appealing but remains controversial. Here, we study a generalized model of ecological communities and investigate how the level of initial diversity influences the possibility of evolutionary diversification. We show that even simple models of intra- and inter-specific ecological interactions can predict a positive effect of diversity on diversification: adaptive radiations may require a threshold number of species before kicking-off. We call this phenomenon DDAR (diversity-dependent adaptive radiations) and identify mathematically two distinct pathways connecting diversity to diversification, involving character displacement and the positive diversity-productivity relationship. Our results may explain observed delays in adaptive radiations at the macroscale and diversification patterns reported in experimental microbial communities, and shed new light on the dynamics of ecological diversity, the diversity-dependence of diversification rates, and the consequences of biodiversity loss.

  9. Diversity spurs diversification in ecological communities.

    PubMed

    Calcagno, Vincent; Jarne, Philippe; Loreau, Michel; Mouquet, Nicolas; David, Patrice

    2017-06-09

    Diversity is a fundamental, yet threatened, property of ecological systems. The idea that diversity can itself favour diversification, in an autocatalytic process, is very appealing but remains controversial. Here, we study a generalized model of ecological communities and investigate how the level of initial diversity influences the possibility of evolutionary diversification. We show that even simple models of intra- and inter-specific ecological interactions can predict a positive effect of diversity on diversification: adaptive radiations may require a threshold number of species before kicking-off. We call this phenomenon DDAR (diversity-dependent adaptive radiations) and identify mathematically two distinct pathways connecting diversity to diversification, involving character displacement and the positive diversity-productivity relationship. Our results may explain observed delays in adaptive radiations at the macroscale and diversification patterns reported in experimental microbial communities, and shed new light on the dynamics of ecological diversity, the diversity-dependence of diversification rates, and the consequences of biodiversity loss.

  10. A Simplified Analytic Investigation of the Riverside Effects of Sediment Diversions

    DTIC Science & Technology

    2013-09-01

    Riverside Effects of Sediment Diversions by Gary L. Brown , Joseph V. Letter, Jr., Ronald E. Heath, Robert McAdory, Loren L. Wehmeyer, and Brittany L...of sediment loads in the Mississippi River.  The decreased sediment supply to the wetlands due to the lack of hydraulic connection between the...planners are considering the construction of sediment diversions. Sediment diversions typically consist of lateral water diversions, either con

  11. Effects of Massage on Delayed-Onset Muscle Soreness, Swelling, and Recovery of Muscle Function

    PubMed Central

    Zainuddin, Zainal; Newton, Mike; Sacco, Paul; Nosaka, Kazunori

    2005-01-01

    Context: Delayed-onset muscle soreness (DOMS) describes muscle pain and tenderness that typically develop several hours postexercise and consist of predominantly eccentric muscle actions, especially if the exercise is unfamiliar. Although DOMS is likely a symptom of eccentric-exercise–induced muscle damage, it does not necessarily reflect muscle damage. Some prophylactic or therapeutic modalities may be effective only for alleviating DOMS, whereas others may enhance recovery of muscle function without affecting DOMS. Objective: To test the hypothesis that massage applied after eccentric exercise would effectively alleviate DOMS without affecting muscle function. Design: We used an arm-to-arm comparison model with 2 independent variables (control and massage) and 6 dependent variables (maximal isometric and isokinetic voluntary strength, range of motion, upper arm circumference, plasma creatine kinase activity, and muscle soreness). A 2-way repeated-measures analysis of variance and paired t tests were used to examine differences in changes of the dependent variable over time (before, immediately and 30 minutes after exercise, and 1, 2, 3, 4, 7, 10, and 14 days postexercise) between control and massage conditions. Setting: University laboratory. Patients or Other Participants: Ten healthy subjects (5 men and 5 women) with no history of upper arm injury and no experience in resistance training. Intervention(s): Subjects performed 10 sets of 6 maximal isokinetic (90°·s−1) eccentric actions of the elbow flexors with each arm on a dynamometer, separated by 2 weeks. One arm received 10 minutes of massage 3 hours after eccentric exercise; the contralateral arm received no treatment. Main Outcome Measure(s): Maximal voluntary isometric and isokinetic elbow flexor strength, range of motion, upper arm circumference, plasma creatine kinase activity, and muscle soreness. Results: Delayed-onset muscle soreness was significantly less for the massage condition for peak

  12. Effect of Aegle marmelos and Murraya koenigii in treatment of delayed pubertal buffaloes heifers

    PubMed Central

    Baitule, Mohan M.; Gawande, A. P.; Kumar, Umesh; Sahatpure, S. K.; Patil, Manoj S.; Baitule, Mansi M.

    2016-01-01

    alone, were found effective in fertility improvement in delayed pubertal buffalo heifers by increasing ovulation and conception rate. PMID:28096608

  13. Haemodynamic effects of changes in atrioventricular and interventricular delay in cardiac resynchronisation therapy show a consistent pattern: analysis of shape, magnitude and relative importance of atrioventricular and interventricular delay

    PubMed Central

    Whinnett, Z I; Davies, J E R; Willson, K; Manisty, C H; Chow, A W; Foale, R A; Davies, D Wyn; Hughes, A D; Mayet, J; Francis, D P

    2006-01-01

    Objective To assess the haemodynamic effect of simultaneously adjusting atrioventricular (AV) and interventricular (VV) delays. Method 35 different combinations of AV and VV delay were tested by using digital photoplethysmography (Finometer) with repeated alternations to measure relative change in systolic blood pressure (SBPrel) in 15 patients with cardiac resynchronisation devices for heart failure. Results Changing AV delay had a larger effect than changing VV delay (range of SBPrel 21 v 4.2 mm Hg, p < 0.001). Each had a curvilinear effect. The curve of response to AV delay fitted extremely closely to a parabola (average R2  =  0.99, average residual variance 0.8 mm Hg2). The response to VV delay was significantly less curved (quadratic coefficient 67 v 1194 mm Hg/s2, p  =  0.003) and therefore, although the residual variance was equally small (0.8 mm Hg2), the R2 value was 0.7. Reproducibility at two months was good, with the SD of the difference between two measurements of SBPrel being 2.5 mm Hg for AV delay (2% of mean systolic blood pressure) and 1.5 mm Hg for VV delay (1% of mean systolic blood pressure). Conclusions Changing AV and VV delays results in a curvilinear acute blood pressure response. This shape fits very closely to a parabola, which may be valuable information in developing a streamlined clinical protocol. VV delay adjustment provides an additional, albeit smaller, haemodynamic benefit to AV optimisation. PMID:16709698

  14. Effects of allocryptopine on outward potassium current and slow delayed rectifier potassium current in rabbit myocardium

    PubMed Central

    Fu, Yi-Cheng; Zhang, Yu; Tian, Liu-Yang; Li, Nan; Chen, Xi; Cai, Zhong-Qi; Zhu, Chao; Li, Yang

    2016-01-01

    Objective Allocryptopine (ALL) is an effective alkaloid of Corydalis decumbens (Thunb.) Pers. Papaveraceae and has proved to be anti-arrhythmic. The purpose of our study is to investigate the effects of ALL on transmural repolarizing ionic ingredients of outward potassium current (Ito) and slow delayed rectifier potassium current (IKs). Methods The monophasic action potential (MAP) technique was used to record the MAP duration of the epicardium (Epi), myocardium (M) and endocardium (Endo) of the rabbit heart and the whole cell patch clamp was used to record Ito and IKs in cardiomyocytes of Epi, M and Endo layers that were isolated from rabbit ventricles. Results The effects of ALL on MAP of Epi, M and Endo layers were disequilibrium. ALL could effectively reduce the transmural dispersion of repolarization (TDR) in rabbit transmural ventricular wall. ALL decreased the current densities of Ito and IKs in a voltage and concentration dependent way and narrowed the repolarizing differences among three layers. The analysis of gating kinetics showed ALL accelerated the channel activation of Ito in M layers and partly inhibit the channel openings of Ito in Epi, M and Endo cells. On the other hand, ALL mainly slowed channel deactivation of IKs channel in Epi and Endo layers without affecting its activation. Conclusions Our study gives partially explanation about the mechanisms of transmural inhibition of Ito and IKs channels by ALL in rabbit myocardium. These findings provide novel perspective regarding the anti-arrhythmogenesis application of ALL in clinical settings. PMID:27403141

  15. Delayed effects of coffee, tea and sucrose on postprandial glycemia in lean, young, healthy adults.

    PubMed

    Louie, Jimmy Chun Yu; Atkinson, Fiona; Petocz, Peter; Brand-Miller, Jennie C

    2008-01-01

    In observational studies, habitual coffee consumption has been linked to a lower risk of type 2 diabetes. We hy-pothesized that the mechanism may be related to delayed effects on postprandial glycemia. The aim of this study is to investigate the glycemic and insulinemic effects of consumption of caffeinated and decaffeinated coffee, sweetened and unsweetened, tea and sucrose, 1 h prior to a high carbohydrate meal. On separate occasions in random order, lean young healthy subjects (n = 8) consumed a potato-based meal 1 hour after consumption of 250 mL of black coffee (COF), black coffee sweetened with 10 g of sucrose (COF+SUC), decaffeinated coffee (DECAF), black tea (TEA), 10 g sucrose (SUC) or hot water (CON). Fingerprick blood samples were taken at regular intervals over 2 h and the glucose and insulin responses quantified as area under the curve. Compared to CON, COF caused a 28% increase in postprandial glycemia (p = 0.022). In contrast, COF+SUC decreased glycemia compared with either COF (-38%, p<0.001) or CON (-20%, p = 0.100) but had no effect on insulin responses. DECAF, TEA and SUC had no significant effects on postprandial responses. SUC and DECAF reduced the absolute glucose concentration at the start of the meal (p<0.01). In conclusion, only sweetened coffee significantly reduces postprandial glycemia. This observation may explain the paradoxical findings of observational and clinical studies relating coffee drinking to diabetes risk.

  16. Effects of AV delay and VV delay on left atrial pressure and waveform in ambulant heart failure patients: insights into CRT optimization.

    PubMed

    Chan, W Y Wandy; Blomqvist, Andreas; Melton, Iain C; Norén, Kjell; Crozier, Ian G; Benser, Michael E; Eigler, Neal L; Gutfinger, Dan; Troughton, Richard W

    2014-07-01

    We hypothesized that left atrial pressure (LAP) obtained by a permanent implantable sensor is sensitive to changes in cardiac resynchronization therapy (CRT) settings and could guide CRT optimization to improve the response rate. We investigated the effect of CRT optimization on LAP and its waveform parameters in ambulant heart failure (HF) patients. CRT optimization was performed in eight ambulant HF patients, using echocardiography as reference. LAP waveform was acquired at each of eight atrioventricular (AV) intervals and five inter-ventricular (VV) intervals. Selected waveform parameters were also evaluated for their sensitivity to CRT changes and agreement with echocardiography-guided optimal settings. Optimal AV and VV intervals varied considerably between patients. All patients exhibited significant changes in waveform morphology with AV optimization. Optimal AV delay determined from echocardiography ranged between 140 ms and 225 ms. Mean LAP tended to be lower at optimal setting 14 ± 3 mmHg compared to shorter (<100 ms) or longer (>160 ms) AV settings (P = 0.16). There were clear trends to smaller peak a-wave (P = 0.11) and gentler positive a-slope (P = 0.15) and positive v-slope (P = 0.09) with longer AV delays. Mean LAP and negative v-wave slope correlated well with echo-guided optimal setting, r = 0.91 (P = 0.001) and 0.79 (P = 0.03), respectively. No significant effects on LAP or waveform were seen during VV optimization. LAP and its waveform changes considerably with AV optimization. There is good agreement between echo-guided optimal setting and LAP. LAP could provide an objective guide to CRT optimization. (Clinical Trial Registry information: URL: http://www.clinicaltrials.gov. Unique Identifier: NCT00632372). ©2014 Wiley Periodicals, Inc.

  17. 76 FR 82116 - Wage Methodology for the Temporary Non-Agricultural Employment H-2B Program; Delay of Effective...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-30

    ... Employment and Training Administration 20 CFR Part 655 RIN 1205-AB61 Wage Methodology for the Temporary Non... delayed the effective date of the Wage Methodology for Temporary Non-agricultural Employment H-2B Program... based on a previous effective date of the new prevailing wage methodology. This guidance...

  18. Effects of Response-Signal Temporal Separation on Behavior Maintained under Temporally Defined Schedules of Delayed Signaled Reinforcement

    ERIC Educational Resources Information Center

    Pulido, Marco A.; Martinez, Guillermo

    2010-01-01

    The present study assessed the effects of systematically separating the cue from the response in temporally defined schedules of delayed signaled reinforcement. Identical schedules were used to study the effects of the independent variable on response acquisition and response maintenance. In the first experiment, 8 groups of 3 naive rats were…

  19. Early and Delayed Effect of Functional Endoscopic Sinus Surgery on Intraocular Pressure

    PubMed Central

    El-Anwar, Mohammad Waheed; Abdelhady, Mohammad; Amer, Hazem Saeed; Ghali, Manar A.

    2016-01-01

    Introduction Due to the close anatomical relationship between the paranasal sinuses and the orbit, involvement or injury of the orbit from paranasal sinuses procedures may occur. Objectives We aimed to study the early and delayed effect of endoscopic sinus surgery on intraocular pressure (IOP). Methods We included in the study 38 patients with chronic rhinosinusitis (CRS), undergoing FESS. We performed FESS with the standard anterior to posterior approach. We measured IOP at the same time one day before surgery as well as day 1 and 6 weeks after surgery. Results One day after surgery, mean IOP in the right eye was 14.176 ± 1.91 mm Hg and in the left eye was 13.79 ± 2.42 mm Hg with statistically non-significant difference from preoperative values. Six weeks postoperative, the mean IOP in the right eye was 15.14 ± 2.28 mm Hg. The difference between the mean preoperative and postoperative IOP values was found to be statistically significant (p = 0.0012). While in the left eye, mean postoperative IOP was 15.14 + 2.23mm Hg. The difference between the mean preoperative and postoperative IOP values was also found to be highly statistically significant (p = 0.0005). Conclusion Delayed significant increase in IOP can occur after FESS, Thus, special measures must be taken to reduce IOP to protect the patient́s eye from the risk of increased IOP, especially in patients with glaucoma. PMID:27746840

  20. Primary Blast Causes Delayed Effects without Cell Death in Shell-Encased Brain Cell Aggregates.

    PubMed

    Sawyer, Thomas W; Ritzel, David V; Wang, Yushan; Josey, Tyson; Villanueva, Mercy; Nelson, Peggy; Song, Yanfeng; Shei, Yimin; Hennes, Grant; Vair, Cory; Parks, Steve; Fan, Changyang; McLaws, Lori

    2017-09-14

    Previous work in this laboratory used underwater explosive exposures to isolate the effects of shock-induced principle stress without shear on rat brain aggregate cultures. The current study has utilized simulated air blast to expose aggregates in suspension and enclosed within a spherical shell, enabling the examination of a much more complex biomechanical insult. Culture medium-filled spheres were exposed to single pulse overpressures of 15-30 psi (∼6-7 msec duration) and measurements within the sphere at defined sites showed complex and spatially dependent pressure changes. When brain aggregates were exposed to similar conditions, no cell death was observed and no changes in several commonly used biomarkers of traumatic brain injury (TBI) were noted. However, similarly to underwater blast, immediate and transient increases in the protein kinase B signaling pathway were observed at early time-points (3 days). In contrast, the oligodendrocyte marker 2',3'-cyclic nucleotide 3'-phosphodiesterase, as well as vascular endothelial growth factor, both displayed markedly delayed (14-28 days) and pressure-dependent responses. The imposition of a spherical shell between the single pulse shock wave and the target brain tissue introduces greatly increased complexity to the insult. This work shows that brain tissue can not only discriminate the nature of the pressure changes it experiences, but that a portion of its response is significantly delayed. These results have mechanistic implications for the study of primary blast-induced TBI and also highlight the importance of rigorously characterizing the actual pressure variations experienced by target tissue in primary blast studies.

  1. Effects of Delaying Transplanting on Agronomic Traits and Grain Yield of Rice under Mechanical Transplantation Pattern

    PubMed Central

    Liu, Qihua; Wu, Xiu; Ma, Jiaqing; Chen, Bocong; Xin, Caiyun

    2015-01-01

    A delay in the mechanical transplantation (MT) of rice seedlings frequently occurs in Huanghuai wheat-rice rotation cropping districts of China, due to the late harvest of wheat, the poor weather conditions and the insufficiency of transplanters, missing the optimum transplanting time and causing seedlings to age. To identify how delaying transplanting rice affects the agronomic characteristics including the growth duration, photosynthetic productivity and dry matter remobilization efficiency and the grain yield under mechanical transplanting pattern, an experiment with a split-plot design was conducted over two consecutive years. The main plot includes two types of cultivation: mechanical transplanting and artificial transplanting (AT). The subplot comprises four japonica rice cultivars. The results indicate that the rice jointing, booting, heading and maturity stages were postponed under MT when using AT as a control. The tiller occurrence number, dry matter weight per tiller, accumulative dry matter for the population, leaf area index, crop growth rate, photosynthetic potential, and dry matter remobilization efficiency of the leaf under MT significantly decreased compared to those under AT. In contrast, the reduction rate of the leaf area during the heading-maturity stage was markedly enhanced under MT. The numbers of effective panicles and filled grains per panicle and the grain yield significantly decreased under MT. A significant correlation was observed between the dry matter production, remobilization and distribution characteristics and the grain yield. We infer that, as with rice from old seedlings, the decrease in the tiller occurrence, the photosynthetic productivity and the assimilate remobilization efficiency may be important agronomic traits that are responsible for the reduced grain yield under MT. PMID:25875607

  2. Effect of Microcurrent Stimulation on Delayed-Onset Muscle Soreness: A Double-Blind Comparison

    PubMed Central

    Allen, Jennifer D.; Mattacola, Carl G.; Perrin, David H.

    1999-01-01

    Objective: To examine the efficacy of microcurrent electrical neuromuscular stimulation (MENS) treatment on pain and loss of range of motion (ROM) associated with delayed-onset muscle soreness (DOMS). Design and Setting: We assigned subjects to 1 of 2 groups. Group 1 received treatment with microcurrent stimulation (200 μA, 30 Hz, for 10 minutes, then 100 μA, 0.3 Hz, for 10 minutes) 24, 48, and 72 hours after DOMS induction. Group 2 served as a sham group and was treated using a machine altered by the manufacturer so that no current could flow through the electrodes. Subjects: DOMS was induced in the biceps brachii of the nondominant arm of 18 subjects (3 males, 15 females: age = 20.33 ± 2.3 years, ht = 170.81 ± 7.3 cm, wt = 69.61 ± 13.1 kg). Dominance was defined as the arm used by the subject to throw a ball. Measurements: Subjective pain and active elbow extension ROM were evaluated before and after treatment each day. Two methods were used to assess pain: constant pressure using a weighted Orthoplast sphere and full elbow extension to the limit of pain tolerance. Subjective pain was measured with a graphic rating scale and active elbow extension ROM using a standard, plastic, double-armed goniometer. Three repeated-measures ANOVAs (between-subjects variable was group, within- subjects variables were day and test) were used to assess ROM and pain scores for the 2 groups. Results: We found no significant difference in the measurement of subjective pain scores or elbow extension ROM when the MENS group was compared with the sham group. Conclusions: Our results indicate that the MENS treatment, within the parameters used for this experiment, was not effective in reducing the pain or loss of ROM associated with delayed-onset muscle soreness. PMID:16558582

  3. Effect of rapid delayed rectifier current on hysteresis in restitution of action potential duration in swine.

    PubMed

    Agarwal, Anuj; Jing, Linyuan; Patwardhan, Abhijit

    2012-01-01

    Electrical stability in the heart depends on two important factors; restitution of action potential duration (APD) and memory. Repolarization currents play an important role in determining APD and also affect memory. We determined the effects of blocking the rapid component of the delayed rectifier (I(Kr)) on a quantifiable measure of memory, i.e. hysteresis in restitution of APD, in swine. Transmembrane potentials were recorded from right ventricular endocardial tissues. Two pacing protocols with explicit control of diastolic interval (DI) were used to change DIs in a sequential and sinusoidal pattern to quantify hysteresis in restitution of APD. E-4031 (5 µM/L) was used to block I(Kr). Measures of memory and restitution were quantified by calculating hysteresis loop thickness, area, overall tilt, and maximum and minimum delays between DIs and APDs. Blocking I(Kr) with E-4031 increased the baseline APD, loop thickness, area, and tilt (p<0.05). However, loop thickness did not increase beyond what could be predicted by the increase in baseline APD after block of I(Kr). The substantial change in APD after blocking I(Kr) suggests that this current plays a major role in repolarization in the swine. Loop thickness is a measure of memory, an increase in which is predicted by theory to reduce instability in activation. In our study, the substantial increase in loop thickness could be accounted for by an equally substantial increase in APD and therefore does not necessarily indicate increased memory after blocking I(Kr). Our results also suggest that factors based on restitution and memory need to be considered in the context of operating point, i.e. baseline APD, when they are used to explore mechanisms that affect electrical stability in the heart.

  4. Delayed surgical management is not effective for severe Bell's palsy after two months of onset.

    PubMed

    Li, Yang; Sheng, Ying; Feng, Guo-Dong; Wu, Hai-Yan; Gao, Zhi-Qiang

    2016-11-01

    To assess the effectiveness of delayed surgery and follow-up observation in managing severe Bell's palsy after two months of onset. Forty-one Bell's palsy patients with severe facial paralysis were treated after two months of onset. Eighteen patients in group I underwent decompression operations between two and three months after onset, and eight patients in group II underwent surgery after three months of onset; 15 patients in group III were managed with follow-up observation. All patients were followed up at the end of 3rd, 6th and 12th months, and surgical outcomes were compared with follow-up observations using House-Brackmann score and Facial Clinimetric Evaluation (FaCE) scale. Between groups I and III, the difference in the proportion of the patients with fair or poor recoveries was statistically significant (p < 0.05) at the three-month follow-up visit. There was no significant difference in the distribution of complete, fair or poor recoveries at the 12-month follow-up visits among the three groups (p < 0.05). The total FaCE score and five individual domains were significantly improved at the end of the follow-up period in groups I and III (p < 0.05). However, in group I, the lacrimal control scores were significantly decreased at the end of the follow-up period compared to scores before surgery (p < 0.05). After surgery, four patients had sensorineural hearing loss, three patients had tinnitus and no patients had vertigo. Patients with severe Bell's palsy after two months of onset would not benefit from delayed decompression surgery.

  5. Effect of microcurrent stimulation on delayed-onset muscle soreness: a double-blind comparison.

    PubMed

    Allen, J D; Mattacola, C G; Perrin, D H

    1999-10-01

    To examine the efficacy of microcurrent electrical neuromuscular stimulation (MENS) treatment on pain and loss of range of motion (ROM) associated with delayed-onset muscle soreness (DOMS). We assigned subjects to 1 of 2 groups. Group 1 received treatment with microcurrent stimulation (200 muA, 30 Hz, for 10 minutes, then 100 muA, 0.3 Hz, for 10 minutes) 24, 48, and 72 hours after DOMS induction. Group 2 served as a sham group and was treated using a machine altered by the manufacturer so that no current could flow through the electrodes. DOMS was induced in the biceps brachii of the nondominant arm of 18 subjects (3 males, 15 females: age = 20.33 +/- 2.3 years, ht = 170.81 +/- 7.3 cm, wt = 69.61 +/- 13.1 kg). Dominance was defined as the arm used by the subject to throw a ball. Subjective pain and active elbow extension ROM were evaluated before and after treatment each day. Two methods were used to assess pain: constant pressure using a weighted Orthoplast sphere and full elbow extension to the limit of pain tolerance. Subjective pain was measured with a graphic rating scale and active elbow extension ROM using a standard, plastic, double-armed goniometer. Three repeated-measures ANOVAs (between-subjects variable was group, within- subjects variables were day and test) were used to assess ROM and pain scores for the 2 groups. We found no significant difference in the measurement of subjective pain scores or elbow extension ROM when the MENS group was compared with the sham group. Our results indicate that the MENS treatment, within the parameters used for this experiment, was not effective in reducing the pain or loss of ROM associated with delayed-onset muscle soreness.

  6. Delayed effects of a low volume, power-type resistance exercise session on explosive performance.

    PubMed

    Tsoukos, Athanasios; Veligekas, Panagiotis; Brown, Lee E; Terzis, Gerasimos; Bogdanis, Gregory C

    2017-01-24

    This study examined the delayed effects of a power type training session on explosive performance. Seventeen well-trained male power and team sport athletes (age: 22.7±5.5 y, height: 181±8 cm, body mass: 80.7±8.6 kg, body fat: 9.2±1.7 %, 1-RM half-squat: 163±29 kg) performed four sessions (2 experimental and 2 control) one week apart in a randomized and counterbalanced order. Explosive performance was assessed before, 24 and 48 h following a low-volume, power-type training session (5 x 4 jump squats at 40% 1RM with 3 min rest), as well as before and after 24 and 48 h of rest (control). Dependent variables were: countermovement jump (CMJ), reactive strength index (RSI) during a drop jump, leg press maximum isometric force and rate of force development (RFD) at three time windows: 0-100, 0-200 and 0-300 ms. ANOVA revealed no changes in the control conditions. In contrast following training, CMJ was improved by 5.1 ± 1.0% and 3.0 ± 1.0% at 24 and 48 h, respectively, compared to baseline. RSI improved by 10.7 ± 2.1% only at 24 h. RFD increased at all time-windows at 24 h (range of improvement: 9.7±3.4% to 18.3±4.1%, p<0.01). However, at 48 h, improvement was only seen in RFD0-100 (9.8±3.1%, p<0.01). These findings suggest that a low-volume, power-type training session results in delayed enhancement of explosive muscle performance, which is greatest at 24 h after the activity. Athletes are advised to perform power type training 1 day before competition or a high quality training session to improve their performances.

  7. Effects of time delay and space on herbivore dynamics: linking inducible defenses of plants to herbivore outbreak.

    PubMed

    Sun, Gui-Quan; Wang, Su-Lan; Ren, Qian; Jin, Zhen; Wu, Yong-Ping

    2015-06-18

    Empirical results indicate that inducible defenses of plants have effects on herbivore populations. However, little is known about how inducible defenses of plants have influences on herbivore outbreak when space effect is considered. To reveal the relationship between inducible defenses and herbivore outbreak, we present a mathematical model to describe the interaction of them. It was found that time delay plays dual effects in the persistence of herbivore populations: (i) large value of time delay may be associated with small density of herbivore populations, and thus causes the populations to run a higher risk of extinction; (ii) moderate value of time delay is beneficial for maintaining herbivore density in a determined range which may promote the persistence of herbivore populations. Additionally, we revealed that interaction of time delay and space promotes the growth of average density of herbivore populations during their outbreak period which implied that time delay may drive the resilience of herbivore populations. Our findings highlight the close relationship between inducible defenses of plants and herbivore outbreak.

  8. Effects of time delay and space on herbivore dynamics: linking inducible defenses of plants to herbivore outbreak

    PubMed Central

    Sun, Gui-Quan; Wang, Su-Lan; Ren, Qian; Jin, Zhen; Wu, Yong-Ping

    2015-01-01

    Empirical results indicate that inducible defenses of plants have effects on herbivore populations. However, little is known about how inducible defenses of plants have influences on herbivore outbreak when space effect is considered. To reveal the relationship between inducible defenses and herbivore outbreak, we present a mathematical model to describe the interaction of them. It was found that time delay plays dual effects in the persistence of herbivore populations: (i) large value of time delay may be associated with small density of herbivore populations, and thus causes the populations to run a higher risk of extinction; (ii) moderate value of time delay is beneficial for maintaining herbivore density in a determined range which may promote the persistence of herbivore populations. Additionally, we revealed that interaction of time delay and space promotes the growth of average density of herbivore populations during their outbreak period which implied that time delay may drive the resilience of herbivore populations. Our findings highlight the close relationship between inducible defenses of plants and herbivore outbreak. PMID:26084812

  9. Prospective memory deficits in Ecstasy users: effects of longer ongoing task delay interval.

    PubMed

    Weinborn, Michael; Woods, Steven Paul; Nulsen, Claire; Park, Katherine

    2011-12-01

    Ecstasy use has been associated with neurotoxicity and neurocognitive impairment in a variety of domains, including prospective memory (ProM), which involves the delayed execution of a previously encoded intention in response to a specific cue. The present study adopted the multiprocess theory of ProM to evaluate the hypothesis that Ecstasy users would evidence differentially impaired ProM on longer versus shorter ongoing task delays. Ecstasy (n = 31) users, high-risk alcohol users (n = 21), and healthy nonusers (n = 31) completed the short (2-min) and long (15-min) delay ProM scales of the Memory for Intentions Screening Test. Results showed a significant group by ProM delay interaction, such that Ecstasy users performed comparably to the comparison groups on short-delay trials, but were impaired on long-delay ProM, particularly for time-based cues. Among the Ecstasy users, long-delay ProM was positively associated with risky decision making, but not with retrospective memory or other aspects of executive functions. These findings suggest that Ecstasy users may be particularly susceptible to deficits in strategic target monitoring and maintenance of cue-intention pairings over longer ProM delays. Findings are discussed in the context of their potential everyday functioning (e.g., academic, vocational) and treatment implications for Ecstasy users.

  10. Prospective Memory Deficits in Ecstasy Users: Effects of Longer Ongoing Task Delay Interval

    PubMed Central

    WEINBORN, MICHAEL; WOODS, STEVEN PAUL; NULSEN, CLAIRE; PARK, KATHERINE

    2011-01-01

    Ecstasy use has been associated with neurotoxicity and neurocognitive impairment in a variety of domains, including prospective memory (ProM), which involves the delayed execution of a previously encoded intention in response to a specific cue. The present study adopted the multiprocess theory of ProM to evaluate the hypothesis that ecstasy users would evidence differentially impaired ProM on longer versus shorter ongoing task delays. Ecstasy (n = 31) users, high-risk alcohol users (n = 21) and healthy nonusers (n = 31) completed the short (2-min) and long (15-min) delay ProM scales of the Memory for Intentions Screening Test. Results showed a significant group by ProM delay interaction, such that ecstasy users performed comparably to the comparison groups on short-delay trials, but were impaired on long-delay ProM, particularly for time-based cues. Among the ecstasy users, long-delay ProM was positively associated with risky decision-making, but not with retrospective memory or other aspects of executive functions. These findings suggest that ecstasy users may be particularly susceptible to deficits in strategic target monitoring and maintenance of cue-intention pairings over longer ProM delays. Findings are discussed in the context of their potential everyday functioning (e.g., academic, vocational) and treatment implications for ecstasy users. PMID:22047194

  11. The Effects of Aging on Time Reproduction in Delayed Free-Recall

    ERIC Educational Resources Information Center

    Rakitin, B.C.; Stern, Y.; Malapani, C.

    2005-01-01

    The experiments presented here demonstrate that normal aging amplifies differences in time production occurring in delayed free-recall testing. Experiment 1 compared the time production ability of two healthy aged groups as well as college-aged participants. During the test session, which followed a 24-h delay and omitted all feedback and examples…

  12. The effects of perceived USB-delay for sensor and embedded system development.

    PubMed

    Du, J; Kade, D; Gerdtman, C; Ozcan, O; Linden, M

    2016-08-01

    Perceiving delay in computer input devices is a problem which gets even more eminent when being used in healthcare applications and/or in small, embedded systems. Therefore, the amount of delay found as acceptable when using computer input devices was investigated in this paper. A device was developed to perform a benchmark test for the perception of delay. The delay can be set from 0 to 999 milliseconds (ms) between a receiving computer and an available USB-device. The USB-device can be a mouse, a keyboard or some other type of USB-connected input device. Feedback from performed user tests with 36 people form the basis for the determination of time limitations for the USB data processing in microprocessors and embedded systems without users' noticing the delay. For this paper, tests were performed with a personal computer and a common computer mouse, testing the perception of delays between 0 and 500 ms. The results of our user tests show that perceived delays up to 150 ms were acceptable and delays larger than 300 ms were not acceptable at all.

  13. The Effect of Brief Delays to Reinforcement on the Acquisition of Tacts in Children with Autism

    ERIC Educational Resources Information Center

    Majdalany, Lina; Wilder, David A.; Smeltz, Lindsay; Lipschultz, Joshua

    2016-01-01

    We used discrete-trial training to teach 3 children with autism to tact shapes of countries using 3 levels of reinforcement delay for correct responding: 0 s (immediate delivery), 6 s, and 12 s. Two of the 3 participants acquired the targets more quickly in the immediate-delivery condition, suggesting that delays as brief as 6 s may be detrimental…

  14. The Effects of Delaying Tracking in Secondary School: Evidence from the 1999 Education Reform in Poland

    ERIC Educational Resources Information Center

    Jakubowski, Maciej; Patrinos, Harry Anthony; Porta, Emilio Ernesto; Wisniewski, Jerzy

    2016-01-01

    Delaying tracking, extending students' exposure to a general academic education and increasing their time on task on basic competences (reading, mathematics) could improve academic outcomes. To test the hypothesis that delayed vocational streaming improves academic outcomes, this paper analyzes Poland's significant improvements in international…

  15. The effect of consumption delay on the excitation of Goodwin's oscillations

    NASA Astrophysics Data System (ADS)

    Antonova, A. O.; Reznik, S. N.; Todorov, M. D.

    2014-11-01

    We investigate the influence of the consumption delay in Godwin's model of the business cycle on the excitation of the Goodwin oscillation, its amplitude and period. We show that the amplitudes of the oscillations of income, consumption and induced investment fall with the increasing the consumption delay.

  16. The Effect of Brief Delays to Reinforcement on the Acquisition of Tacts in Children with Autism

    ERIC Educational Resources Information Center

    Majdalany, Lina; Wilder, David A.; Smeltz, Lindsay; Lipschultz, Joshua

    2016-01-01

    We used discrete-trial training to teach 3 children with autism to tact shapes of countries using 3 levels of reinforcement delay for correct responding: 0 s (immediate delivery), 6 s, and 12 s. Two of the 3 participants acquired the targets more quickly in the immediate-delivery condition, suggesting that delays as brief as 6 s may be detrimental…

  17. The Effects of Delaying Tracking in Secondary School: Evidence from the 1999 Education Reform in Poland

    ERIC Educational Resources Information Center

    Jakubowski, Maciej; Patrinos, Harry Anthony; Porta, Emilio Ernesto; Wisniewski, Jerzy

    2016-01-01

    Delaying tracking, extending students' exposure to a general academic education and increasing their time on task on basic competences (reading, mathematics) could improve academic outcomes. To test the hypothesis that delayed vocational streaming improves academic outcomes, this paper analyzes Poland's significant improvements in international…

  18. Scopolamine Effects Under a Titrating-Delayed-Nonmatching-to-Position Procedure

    ERIC Educational Resources Information Center

    Porritt, M.; Poling, A.

    2008-01-01

    In a study of working memory, the performance of rats under titrating-delayed-nonmatching- to-position (TDNMTP) procedures was examined. Overall accuracy and the number of trials completed were inversely related to titration value, whereas the highest delay attained was directly related to titration value. When given intraperitoneally,…

  19. Scopolamine Effects Under a Titrating-Delayed-Nonmatching-to-Position Procedure

    ERIC Educational Resources Information Center

    Porritt, M.; Poling, A.

    2008-01-01

    In a study of working memory, the performance of rats under titrating-delayed-nonmatching- to-position (TDNMTP) procedures was examined. Overall accuracy and the number of trials completed were inversely related to titration value, whereas the highest delay attained was directly related to titration value. When given intraperitoneally,…

  20. The Effect of Delayed Responding on Stroop-Like Task Performance among Preschoolers

    ERIC Educational Resources Information Center

    Montgomery, Derek E.; Fosco, Whitney

    2012-01-01

    Forty-four preschoolers completed 2 conditions of a Stroop-like procedure (e.g., saying "boat" for car and "car" for boat) that differed in whether a 3-s delay was imposed before responding. The test card was visible during the delay period for half of the children and occluded for the other children. Preschoolers' interference control was…

  1. The Effects of Aging on Time Reproduction in Delayed Free-Recall

    ERIC Educational Resources Information Center

    Rakitin, B.C.; Stern, Y.; Malapani, C.

    2005-01-01

    The experiments presented here demonstrate that normal aging amplifies differences in time production occurring in delayed free-recall testing. Experiment 1 compared the time production ability of two healthy aged groups as well as college-aged participants. During the test session, which followed a 24-h delay and omitted all feedback and examples…

  2. The Effect of Delayed Responding on Stroop-Like Task Performance among Preschoolers

    ERIC Educational Resources Information Center

    Montgomery, Derek E.; Fosco, Whitney

    2012-01-01

    Forty-four preschoolers completed 2 conditions of a Stroop-like procedure (e.g., saying "boat" for car and "car" for boat) that differed in whether a 3-s delay was imposed before responding. The test card was visible during the delay period for half of the children and occluded for the other children. Preschoolers' interference control was…

  3. Effect of intermittent kangaroo mother care on weight gain of low birth weight neonates with delayed weight gain.

    PubMed

    Samra, Nashwa M; Taweel, Amal El; Cadwell, Karin

    2013-01-01

    To evaluate intermittent Kangaroo Mother Care (KMC) with additional opportunities to breastfeed on weight gain of low birth weight (LBW) neonates with delayed weight gain. 40 LBW neonates were followed to see whether KMC with additional opportunities to breastfeed improved weight gain. In the KMC group, the mean age of regaining birth weight was significantly less (15.68 vs. 24.56 days) and the average daily weight gain was significantly higher (22.09 vs. 10.39 g, p < .001) than controls. KMC with additional opportunities to breastfeed was found to be an effective intervention for LBWs with delayed weight gain and should be considered to be an effective strategy.

  4. Medicaid program; premiums and cost sharing. Final rule; delay of effective data and reopening of comment period.

    PubMed

    2009-01-27

    In accordance with the memorandum of January 20, 2009, from the Assistant to the President and Chief of Staff, entitled "Regulatory Review Plan," this action temporarily delays for 60 days the effective date of the final rule entitled "Medicaid Program; Premiums and Cost Sharing" (73 FR 71828). The temporary 60-day delay in effective date is necessary to give Department officials the opportunity for further review and consideration of new regulations. In addition, this action reopens the comment period on the policies set out in the November 25, 2008 final rule.

  5. Effect of delay on self-administration of remifentanil under a drug versus drug choice procedure in rhesus monkeys.

    PubMed

    Maguire, David R; Gerak, Lisa R; France, Charles P

    2013-12-01

    Drug abuse can be conceptualized as excessive choice of drug over other reinforcers, and factors that affect drug taking can be examined experimentally using choice procedures. This study examined the impact of reinforcer delay on self-administration of the μ-opioid receptor agonist remifentanil in rhesus monkeys (n = 4) lever pressing under a concurrent fixed-ratio 30 schedule. Responding on either lever delivered an intravenous infusion of either remifentanil or saline. Dose-effect curves were first determined when responding on one lever delivered remifentanil and responding on a second lever delivered saline. Monkeys then chose between two doses of remifentanil, and delay to delivery of the large dose was varied systematically. Responding for remifentanil (0.01-1.0 µg/kg/infusion) increased dose-dependently when the alternative was saline or a dose of remifentanil. Delaying delivery of the large dose of remifentanil by 30, 60, 120, or 240 seconds increased responding for smaller, immediately available doses (0.01-0.1 µg/kg/infusion) and, in some cases, increased responding for doses of remifentanil that did not maintain responding when the alternative was saline. These data demonstrate that delaying the delivery of an opioid receptor agonist can significantly affect its reinforcing effectiveness. The imposition of a delay reduces the effectiveness of large doses of drug to maintain responding and increases the effectiveness of immediately available commodities, including smaller doses of drug. Increased reinforcing effectiveness of smaller doses of drug in the context of other delayed reinforcers might contribute to the development and maintenance of opioid abuse.

  6. Effect of delayed peripheral nerve repair on nerve regeneration, Schwann cell function and target muscle recovery.

    PubMed

    Jonsson, Samuel; Wiberg, Rebecca; McGrath, Aleksandra M; Novikov, Lev N; Wiberg, Mikael; Novikova, Liudmila N; Kingham, Paul J

    2013-01-01

    Despite advances in surgical techniques for peripheral nerve repair, functional restitution remains incomplete. The timing of surgery is one factor influencing the extent of recovery but it is not yet clearly defined how long a delay may be tolerated before repair becomes futile. In this study, rats underwent sciatic nerve transection before immediate (0) or 1, 3, or 6 months delayed repair with a nerve graft. Regeneration of spinal motoneurons, 13 weeks after nerve repair, was assessed using retrograde labeling. Nerve tissue was also collected from the proximal and distal stumps and from the nerve graft, together with the medial gastrocnemius (MG) muscles. A dramatic decline in the number of regenerating motoneurons and myelinated axons in the distal nerve stump was observed in the 3- and 6-months delayed groups. After 3 months delay, the axonal number in the proximal stump increased 2-3 folds, accompanied by a smaller axonal area. RT-PCR of distal nerve segments revealed a decline in Schwann cells (SC) markers, most notably in the 3 and 6 month delayed repair samples. There was also a progressive increase in fibrosis and proteoglycan scar markers in the distal nerve with increased delayed repair time. The yield of SC isolated from the distal nerve segments progressively fell with increased delay in repair time but cultured SC from all groups proliferated at similar rates. MG muscle at 3- and 6-months delay repair showed a significant decline in weight (61% and 27% compared with contra-lateral side). Muscle fiber atrophy and changes to neuromuscular junctions were observed with increased delayed repair time suggestive of progressively impaired reinnervation. This study demonstrates that one of the main limiting factors for nerve regeneration after delayed repair is the distal stump. The critical time point after which the outcome of regeneration becomes too poor appears to be 3-months.

  7. Effect of Delayed Peripheral Nerve Repair on Nerve Regeneration, Schwann Cell Function and Target Muscle Recovery

    PubMed Central

    Jonsson, Samuel; Wiberg, Rebecca; McGrath, Aleksandra M.; Novikov, Lev N.; Wiberg, Mikael; Novikova, Liudmila N.; Kingham, Paul J.

    2013-01-01

    Despite advances in surgical techniques for peripheral nerve repair, functional restitution remains incomplete. The timing of surgery is one factor influencing the extent of recovery but it is not yet clearly defined how long a delay may be tolerated before repair becomes futile. In this study, rats underwent sciatic nerve transection before immediate (0) or 1, 3, or 6 months delayed repair with a nerve graft. Regeneration of spinal motoneurons, 13 weeks after nerve repair, was assessed using retrograde labeling. Nerve tissue was also collected from the proximal and distal stumps and from the nerve graft, together with the medial gastrocnemius (MG) muscles. A dramatic decline in the number of regenerating motoneurons and myelinated axons in the distal nerve stump was observed in the 3- and 6-months delayed groups. After 3 months delay, the axonal number in the proximal stump increased 2–3 folds, accompanied by a smaller axonal area. RT-PCR of distal nerve segments revealed a decline in Schwann cells (SC) markers, most notably in the 3 and 6 month delayed repair samples. There was also a progressive increase in fibrosis and proteoglycan scar markers in the distal nerve with increased delayed repair time. The yield of SC isolated from the distal nerve segments progressively fell with increased delay in repair time but cultured SC from all groups proliferated at similar rates. MG muscle at 3- and 6-months delay repair showed a significant decline in weight (61% and 27% compared with contra-lateral side). Muscle fiber atrophy and changes to neuromuscular junctions were observed with increased delayed repair time suggestive of progressively impaired reinnervation. This study demonstrates that one of the main limiting factors for nerve regeneration after delayed repair is the distal stump. The critical time point after which the outcome of regeneration becomes too poor appears to be 3-months. PMID:23409189

  8. Effects of mouse genotype on bone wound healing and irradiation-induced delay of healing.

    PubMed

    Glowacki, Julie; Mizuno, Shuichi; Kung, Jason; Goff, Julie; Epperly, Michael; Dixon, Tracy; Wang, Hong; Greenberger, Joel S

    2014-01-01

    We tested the effects of mouse genotype (C57BL/6NHsd, NOD/SCID, SAMR1, and SAMP6) and ionizing irradiation on bone wound healing. Unicortical wounds were made in the proximal tibiae, and the time course of spontaneous healing and effects of irradiation were monitored radiographically and histologically. There was reproducible healing beginning with intramedullary osteogenesis, subsequent bone resorption by osteoclasts, gradual bridging of the cortical wound, and re-population of medullary hematopoietic cells. The most rapid wound closure was noted in SAMR1 mice, followed by SAMP6, C57BL/6NHsd, and NOD/SCID. Ionizing irradiation (20 Gy) to the leg significantly delayed bone wound healing in mice of all four genotypes. Mice with genetically-determined predisposition to early osteopenia (SAMP6) or with immune deficiency (NOD/SCID) had impairments in bone wound healing. These mouse models should be valuable for determining the effects of irradiation on bone healing and also for the design and testing of novel bone growth-enhancing drugs and mitigators of ionizing irradiation.

  9. Serial position functions following selective hippocampal lesions in monkeys: Effects of delays and interference✩

    PubMed Central

    Bachevalier, Jocelyne; Wright, Anthony A.; Katz, Jeffrey S.

    2013-01-01

    We examined the role of the hippocampus in list-memory processing. Three rhesus monkeys that had extensive experience in this task and had demonstrated full abstract-concept learning and excellent list memory performance (Katz et al., 2002; Wright et al., 2003) received bilateral neurotoxic hippocampal lesions and were re-tested in the serial list memory task. Effects of delays on memory performance were measured in all monkeys, whereas the effects of proactive interference were assessed in only one. Despite a slight change in performance of one of the three animals during re-learning of the same/different task, selective hippocampal damage had little or no effects on list memory accuracy. In addition, the hippocampal damage did not impact serial list position functions (SPFs) but slightly altered the dynamic of the SPF curves. Finally, even more remarkable was that accurate memory performance of one animal remained intact despite the use of small set size of 8 items that created high proactive interference across lists thereby eliminating any use of familiarity judgments to support performance. Together the findings indicate that, with short list items and extensive training in the task (i.e., reference memory), monkeys with selective hippocampal lesions may be able to use alternative memory processes (i.e., working memory) that are mediated by structures other than the hippocampus. PMID:23246643

  10. The effects of mands and models on the speech of unresponsive language-delayed preschool children.

    PubMed

    Warren, S F; McQuarter, R J; Rogers-Warren, A K

    1984-02-01

    The effects of the systematic use of mands (non-yes/no questions and instructions to verbalize), models (imitative prompts), and specific consequent events on the productive verbal behavior of three unresponsive, socially isolate, language-delayed preschool children were investigated in a multiple-baseline design within a classroom free play period. Following a lengthy intervention condition, experimental procedures were systematically faded out to check for maintenance effects. The treatment resulted in increases in total verbalizations and nonobligatory speech (initiations) by the subjects. Subjects also became more responsive in obligatory speech situations. In a second free play (generalization) setting, increased rates of total child verbalizations and nonobligatory verbalizations were observed for all three subjects, and two of the three subjects were more responsive compared to their baselines in the first free play setting. Rate of total teacher verbalizations and questions were also higher in this setting. Maintenance of the treatment effects was shown during the fading condition in the intervention setting. The subjects' MLUs (mean length of utterance) increased during the intervention condition when the teacher began prompting a minimum of two-word utterances in response to a mand or model.

  11. The Immediate and Delayed Effects of TV: Impacts of Gender and Processed-Food Intake History

    PubMed Central

    Francis, Heather M.; Stevenson, Richard J.; Oaten, Megan J.; Mahmut, Mehmet K.; Yeomans, Martin R.

    2017-01-01

    Eating while watching TV has generally been found to increase both immediate and delayed energy intake. Here we examine two factors – gender and habitual processed-food intake – that may moderate these effects. Participants [n = 153; 95 women, 58 men; Mage = 19.7 (SD = 2.9); MBMI = 22.4 (SD = 3.1)] ate an ad libitum snack either with or without TV, followed around 1 h later by lunch. There was an interaction between TV and gender for both meals. Women tended to consume more snack food in the TV condition, with men consuming more in the no-TV condition. Participants who habitually consumed more processed food also ate more snacks, independent of any other variable, including rated liking. At lunch, men who had earlier snacked with TV ate more than men who had snacked without TV, but this effect was not evident in women. On memory recall, all participants underestimated how much snack food they had eaten, and this was a function of how much they had actually consumed, with greater error only predicted by greater consumption. The results indicate that the effects of TV on eating can vary with gender and that processed-food history can predict snack food intake. While previous findings suggest memory of prior-intake may be impaired by eating while watching TV, the current results suggest this is not necessarily because of TV per se, but because people sometimes consume more food under such conditions. PMID:28979225

  12. The Immediate and Delayed Effects of TV: Impacts of Gender and Processed-Food Intake History.

    PubMed

    Francis, Heather M; Stevenson, Richard J; Oaten, Megan J; Mahmut, Mehmet K; Yeomans, Martin R

    2017-01-01

    Eating while watching TV has generally been found to increase both immediate and delayed energy intake. Here we examine two factors - gender and habitual processed-food intake - that may moderate these effects. Participants [n = 153; 95 women, 58 men; Mage = 19.7 (SD = 2.9); MBMI = 22.4 (SD = 3.1)] ate an ad libitum snack either with or without TV, followed around 1 h later by lunch. There was an interaction between TV and gender for both meals. Women tended to consume more snack food in the TV condition, with men consuming more in the no-TV condition. Participants who habitually consumed more processed food also ate more snacks, independent of any other variable, including rated liking. At lunch, men who had earlier snacked with TV ate more than men who had snacked without TV, but this effect was not evident in women. On memory recall, all participants underestimated how much snack food they had eaten, and this was a function of how much they had actually consumed, with greater error only predicted by greater consumption. The results indicate that the effects of TV on eating can vary with gender and that processed-food history can predict snack food intake. While previous findings suggest memory of prior-intake may be impaired by eating while watching TV, the current results suggest this is not necessarily because of TV per se, but because people sometimes consume more food under such conditions.

  13. Microarray as a first genetic test in global developmental delay: a cost-effectiveness analysis.

    PubMed

    Trakadis, Yannis; Shevell, Michael

    2011-11-01

    Microarray technology has a significantly higher clinical yield than karyotyping in individuals with global developmental delay (GDD). Despite this, it has not yet been routinely implemented as a screening test owing to the perception that this approach is more expensive. We aimed to evaluate the effect that replacing karyotype with array-based comparative genomic hybridization (aCGH) would have on the total cost of the workup for GDD. We evaluated the cost-effectiveness of aCGH compared with karyotyping by retrospectively analysing the cost of workup in a cohort of 114 children (69 males; 45 females) representing a consecutive series of children diagnosed with GDD. The average increase in cost if aCGH had been performed instead of karyotyping as a first test was $442 per individual when performed by a private company (98% confidence interval $238-604). In contrast, $106 (98% confidence interval -$17 to $195) would have been saved if aCGH was performed locally in a laboratory already possessing the required technology. The incremental cost per additional diagnosis was estimated to be $12,874 if aCGH was performed in a private laboratory, but <$1379 if performed locally. (Costs reported in Canadian dollars, using 2010 prices.) aCGH would be cost-effective as a first genetic test in the clinical evaluation of individuals with GDD. © The Authors. Developmental Medicine & Child Neurology © 2011 Mac Keith Press.

  14. Sucrose accelerates flower opening and delays senescence through a hormonal effect in cut lily flowers.

    PubMed

    Arrom, Laia; Munné-Bosch, Sergi

    2012-06-01

    Sugars are generally used to extend the vase life of cut flowers. Such beneficial effects have been associated with an improvement of water relations and an increase in available energy for respiration by floral tissues. In this study we aimed at evaluating to what extent (i) endogenous levels of sugars in outer and inner tepals, androecium and gynoecium are altered during opening and senescence of lily flowers; (ii) sugar levels increase in various floral tissues after sucrose addition to the vase solution; and (iii) sucrose addition alters the hormonal balance of floral tissues. Results showed that endogenous glucose levels increased during flower opening and decreased during senescence in all floral organs, while sucrose levels increased in outer and inner tepals and the androecium during senescence. Sucrose treatment accelerated flower opening, and delayed senescence, but did not affect tepal abscission. Such effects appeared to be exerted through a specific increase in the endogenous levels of sucrose in the gynoecium and of glucose in all floral tissues. The hormonal balance was altered in the gynoecium as well as in other floral tissues. Aside from cytokinin and auxin increases in the gynoecium; cytokinins, gibberellins, abscisic acid and salicylic acid levels increased in the androecium, while abscisic acid decreased in outer tepals. It is concluded that sucrose addition to the vase solution exerts an effect on flower opening and senescence by, among other factors, altering the hormonal balance of several floral tissues. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  15. Effect of longer health service provider delays on stage at diagnosis and mortality in symptomatic breast cancer.

    PubMed

    Murchie, P; Raja, E A; Lee, A J; Brewster, D H; Campbell, N C; Gray, N M; Ritchie, L D; Robertson, R; Samuel, L

    2015-06-01

    This study explored whether longer provider delays (between first presentation and treatment) were associated with later stage and poorer survival in women with symptomatic breast cancer. Data from 850 women with symptomatic breast cancer were linked with the Scottish Cancer Registry; Death Registry; and hospital discharge dataset. Logistic regression and Cox survival analyses with restricted cubic splines explored relationships between provider delays, stage and survival, with sequential adjustment for patient and tumour factors. Although confidence intervals were wide in both adjusted analyses, those with the shortest provider delays had more advanced breast cancer at diagnosis. Beyond approximately 20 weeks, the trend suggests longer delays are associated with more advanced stage, but is not statistically significant. Those with symptomatic breast cancer and the shortest presentation to treatment time (within 4 weeks) had the poorest survival. Longer time to treatment was not significantly associated with worsening mortality. Poor prognosis patients with breast cancer are being triaged for rapid treatment with limited effect on outcome. Prolonged time to treatment does not appear to be strongly associated with poorer outcomes for patients with breast cancer, but the power of this study to assess the effect of very long delays (>25 weeks) was limited. Efforts to reduce waiting times are important from a quality of life perspective, but tumour biology may often be a more important determinant of stage at diagnosis and survival outcome. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Exploring relationships among experience of regret, delay discounting, and worries about future effects of smoking among current smokers

    PubMed Central

    O'Connor, Richard; Thrasher, James F.; Bansal-Travers, Maansi

    2016-01-01

    Background Smoking regret differs by smoker characteristics (dependence) and may be linked to delay discounting (DD), where smaller immediate rewards are preferred to larger delayed rewards. It is hypothesized that those who exhibit stronger tendencies to delay rewards also express fewer future health concerns and possibly less regret about smoking. Objectives The objective is to determine the interrelationships of regret, dependence, and delay discounting among current smokers. Methods In July 2010, 1062 smokers completed a 45-minute at-home web based survey and answered questions including regret, dependence (Fagerstrom Test for Cigarette Dependence), and delay discounting (Monetary Choice Questionnaire). Relationships among these variables and perceived future health effects were analyzed using correlations, repeated measures analysis of variance, and generalized linear models. Results Most smokers (85%) regretted smoking. FTCD and log-k (DD) scores were positively associated (rs = 0.15, p<.001). Though a strong decline in log-k was shown as reward increased (p’s<.001), there were no differences in discounting by regret. Regret was positively associated with worries concerning health effects, quality of life, and finances (p’s<.001). Little association was found between DD and future health concerns. Conclusions / Importance Though this study confirms that regret for smoking is associated with perceived future risks as well as supports previous findings between FTCD and DD, it shows little association between DD and perceived future risks. PMID:27192133

  17. The effects of disodium cromoglycate (DSCG) and beclomethasone dipropionate (BDA) on the delayed nasal mucosa response to allergen challenge.

    PubMed

    Pelikan, Z

    1984-02-01

    The protective effects of disodium cromoglycate (DSCG) and beclomethasone dipropionate (BDA) on the "delayed nasal response" to allergen challenge (DNR) were investigated in 37 patients with allergic rhinitis. These thirty-seven patients, from a group of 268, developed 43 "delayed nasal responses" (DNR), 16 cases of "isolated delayed responses" (IDNR) and 27 cases of "dual delayed responses" (DDNR), where the delayed response (DLDNR) was preceded by an immediate response (INR). BDA demonstrated significant protective effects on the DNR in both its modifications; however, to a higher degree in the case of the IDNR. DSCG significantly decreased only the INR, being a part of the DDNR, while in the case of the DNR in both its modifications, DSCG was completely ineffective. It is suggested that BDA should be the drug of first choice in allergic rhinitis patients demonstrating the DNR. When immediate responses to the same or other allergens are also present, DSCG should be added at the beginning of the treatment for a temporary period of a few months.

  18. Delayed protective effect of telmisartan on lung ischemia/reperfusion injury in valve replacement operations

    PubMed Central

    Fan, Yongfeng; Zhang, Daguo; Xiang, Daokang

    2016-01-01

    The present study aimed to investigate the delayed protective effect of telmisartan on lung ischemic/reperfusion injury in patients undergoing heart valve replacement operations. In total, 180 patients diagnosed with rheumatic valve diseases were randomly divided into the telmisartan (T), captopril (C) and placebo (P) groups. In the telmisartan group, the patients were pretreated with telmisartan (1 mg/kg/day), at the time period 96–48 h before the operation, whereas in the C group, the patients were treated with captopril (1 mg/kg/day) at the time period 96–48 h prior to the operation control group. Each drug treatment group included a corresponding placebo treatment. The variables pulmonary vascular resistance (PVR) and A-aDO2 were measured prior to CPB and at 1, 3, 6 and 12 h after CPB. Pulmonary neutrophil (PMN) count in the left and right atrium blood as well as SOD malondialdehyde (MDA), NO, angiotensin II (AngII) value in the left atrium blood, were measured 30 min prior to and after CPB. The PVR parameters of the telmisartan and captopril groups were significantly lower than those of the placebo group (P<0.05). The A-aDO2 values in the telmisartan and captopril groups were significantly lower than those in the placebo group at 1, 3 and 6 h following CPB treatment. The difference between the right and left atrium blood PMN was significantly lower in the telmisartan and captopril intervention groups compared to that in the placebo group 30 min following CPB treatment. The left atrium blood SOD and NO values were significantly higher, whereas the MDA value was significantly lower in the telmisartan group compared to the control group 30 min following CPB treatment. As for AngII, there was no difference between the C and T groups, compared with the P group. In the two groups 30 min after treatment with CPB, 24 patients experienced varying degrees of cough, with the telmisartan group showing a significant difference (P<0.05). The hospitalization time was

  19. Delayed protective effect of telmisartan on lung ischemia/reperfusion injury in valve replacement operations.

    PubMed

    Fan, Yongfeng; Zhang, Daguo; Xiang, Daokang

    2016-10-01

    The present study aimed to investigate the delayed protective effect of telmisartan on lung ischemic/reperfusion injury in patients undergoing heart valve replacement operations. In total, 180 patients diagnosed with rheumatic valve diseases were randomly divided into the telmisartan (T), captopril (C) and placebo (P) groups. In the telmisartan group, the patients were pretreated with telmisartan (1 mg/kg/day), at the time period 96-48 h before the operation, whereas in the C group, the patients were treated with captopril (1 mg/kg/day) at the time period 96-48 h prior to the operation control group. Each drug treatment group included a corresponding placebo treatment. The variables pulmonary vascular resistance (PVR) and A-aDO2 were measured prior to CPB and at 1, 3, 6 and 12 h after CPB. Pulmonary neutrophil (PMN) count in the left and right atrium blood as well as SOD malondialdehyde (MDA), NO, angiotensin II (AngII) value in the left atrium blood, were measured 30 min prior to and after CPB. The PVR parameters of the telmisartan and captopril groups were significantly lower than those of the placebo group (P<0.05). The A-aDO2 values in the telmisartan and captopril groups were significantly lower than those in the placebo group at 1, 3 and 6 h following CPB treatment. The difference between the right and left atrium blood PMN was significantly lower in the telmisartan and captopril intervention groups compared to that in the placebo group 30 min following CPB treatment. The left atrium blood SOD and NO values were significantly higher, whereas the MDA value was significantly lower in the telmisartan group compared to the control group 30 min following CPB treatment. As for AngII, there was no difference between the C and T groups, compared with the P group. In the two groups 30 min after treatment with CPB, 24 patients experienced varying degrees of cough, with the telmisartan group showing a significant difference (P<0.05). The hospitalization time was

  20. Metabolic Effects of Berries with Structurally Diverse Anthocyanins

    PubMed Central

    Overall, John; Bonney, Sierra A.; Wilson, Mickey; Beermann, Arnold; Grace, Mary H.; Esposito, Debora; Lila, Mary Ann; Komarnytsky, Slavko

    2017-01-01

    Overconsumption of energy dense foods and sedentary lifestyle are considered as major causes of obesity-associated insulin resistance and abnormal glucose metabolism. Results from both cohort studies and randomized trials suggested that anthocyanins from berries may lower metabolic risks, however these reports are equivocal. The present study was designed to examine effects of six berries with structurally diverse anthocyanin profiles (normalized to 400 µg/g total anthocyanin content) on development of metabolic risk factors in the C57BL/6 mouse model of polygenic obesity. Diets supplemented with blackberry (mono-glycosylated cyanidins), black raspberry (acylated mono-glycosylated cyanidins), blackcurrant (mono- and di-glycosylated cyanidins and delphinidins), maqui berry (di-glycosylated delphinidins), Concord grape (acylated mono-glycosylated delphinidins and petunidins), and blueberry (mono-glycosylated delphinidins, malvidins, and petunidins) showed a prominent discrepancy between biological activities of delphinidin/malvidin-versus cyanidin-type anthocyanins that could be explained by differences in their structure and metabolism in the gut. Consumption of berries also resulted in a strong shift in the gastrointestinal bacterial communities towards obligate anaerobes that correlated with decrease in the gastrointestinal luminal oxygen and oxidative stress. Further work is needed to understand mechanisms that lead to nearly anoxic conditions in the gut lumens, including the relative contributions of host, diet and/or microbial oxidative activity, and their implication to human health. PMID:28212306