Patterns of and motivations for concurrent use of video games and substances.

PubMed

Ream, Geoffrey L; Elliott, Luther C; Dunlap, Eloise

2011-10-01

"Behavioral addictions" share biological mechanisms with substance dependence, and "drug interactions" have been observed between certain substances and self-reinforcing behaviors. This study examines correlates of patterns of and motivations for playing video games while using or feeling the effects of a substance (concurrent use). Data were drawn from a nationally-representative survey of adult Americans who "regularly" or "occasionally" played video games and had played for at least one hour in the past seven days (n = 3,380). Only recent concurrent users' data were included in analyses (n = 1,196). Independent variables included demographics, substance use frequency and problems, game genre of concurrent use (identified by looking titles up in an industry database), and general game playing variables including problem video game play (PVP), consumer involvement, enjoyment, duration, and frequency of play. Exploratory factor analysis identified the following dimensions underlying patterns of and motivations for concurrent use: pass time or regulate negative emotion, enhance an already enjoyable or positive experience, and use of video games and substances to remediate each other's undesirable effects. Multivariate regression analyses indicated PVP and hours/day of video game play were associated with most patterns/motivations, as were caffeine, tobacco, alcohol, marijuana, and painkiller use problems. This suggests that concurrent use with some regular situational pattern or effect-seeking motivation is part of the addictive process underlying both PVP and substance dependence. Various demographic, game playing, game genre of concurrent use, and substance use variables were associated with specific motivations/patterns, indicating that all are important in understanding concurrent use.

The general matching law describes choice on concurrent variable-interval schedules of wheel-running reinforcement.

PubMed

Belke, T W; Belliveau, J

2001-05-01

Six male Wistar rats were exposed to concurrent variable-interval schedules of wheel-running reinforcement. The reinforcer associated with each alternative was the opportunity to run for 15 s, and the duration of the changeover delay was 1 s. Results suggested that time allocation was more sensitive to relative reinforcement rate than was response allocation. For time allocation, the mean slopes and intercepts were 0.82 and 0.008, respectively. In contrast, for response allocation, mean slopes and intercepts were 0.60 and 0.03, respectively. Correction for low response rates and high rates of changing over, however, increased slopes for response allocation to about equal those for time allocation. The results of the present study suggest that the two-operant form of the matching law can be extended to wheel-running reinforcement. 'I'he effects of a low overall response rate, a short Changeover delay, and long postreinforcement pausing on the assessment of matching in the present study are discussed.

Variation, Repetition, And Choice

PubMed Central

Abreu-Rodrigues, Josele; Lattal, Kennon A; dos Santos, Cristiano V; Matos, Ricardo A

2005-01-01

Experiment 1 investigated the controlling properties of variability contingencies on choice between repeated and variable responding. Pigeons were exposed to concurrent-chains schedules with two alternatives. In the REPEAT alternative, reinforcers in the terminal link depended on a single sequence of four responses. In the VARY alternative, a response sequence in the terminal link was reinforced only if it differed from the n previous sequences (lag criterion). The REPEAT contingency generated low, constant levels of sequence variation whereas the VARY contingency produced levels of sequence variation that increased with the lag criterion. Preference for the REPEAT alternative tended to increase directly with the degree of variation required for reinforcement. Experiment 2 examined the potential confounding effects in Experiment 1 of immediacy of reinforcement by yoking the interreinforcer intervals in the REPEAT alternative to those in the VARY alternative. Again, preference for REPEAT was a function of the lag criterion. Choice between varying and repeating behavior is discussed with respect to obtained behavioral variability, probability of reinforcement, delay of reinforcement, and switching within a sequence. PMID:15828592

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

PubMed

McMillan, D E; Li, M

2000-07-01

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

Time estimation as a secondary task to measure workload: Summary of research

NASA Technical Reports Server (NTRS)

Hart, S. G.; Mcpherson, D.; Loomis, L. L.

1978-01-01

Actively produced intervals of time were found to increase in length and variability, whereas retrospectively produced intervals decreased in length although they also increased in variability with the addition of a variety of flight-related tasks. If pilots counted aloud while making a production, however, the impact of concurrent activity was minimized, at least for the moderately demanding primary tasks that were selected. The effects of feedback on estimation accuracy and consistency were greatly enhanced if a counting or tapping production technique was used. This compares with the minimal effect that feedback had when no overt timekeeping technique was used. Actively made verbal estimates of sessions filled with different activities performed during the interval were increased. Retrospectively made verbal estimates, however, increased in length as the amount and complexity of activities performed during the interval were increased.

The potency of fluvoxamine to reduce ethanol self-administration decreases with concurrent availability of food.

PubMed

Ginsburg, Brett C; Pinkston, Jonathan W; Lamb, Richard J

2012-04-01

The selective serotonin reuptake inhibitor fluvoxamine reduces responding for ethanol at lower doses than responding for food when each is available in separate components or separate groups of rats. However, when both are available concurrently and deliveries earned per session are equal, this apparent selectivity inverts and food-maintained behavior is more sensitive than ethanol-maintained behavior to rate-decreasing effects of fluvoxamine. Here, we investigated further the impact that concurrent access to both food and ethanol has on the potency of fluvoxamine. Fluvoxamine (5.6-17.8 mg/kg) potency was assessed under conditions in which food and ethanol were available concurrently and response rates were equal [average variable intervals (VIs) 405 and 14 s for food and ethanol, respectively], as well as when density of food delivery was increased (average VI 60 s for food and VI 14 s for ethanol). The potency of fluvoxamine was also determined when only ethanol was available (food extinction and average VI 14 s for ethanol) and under multiple VIs (VI 30 s for food and ethanol) wherein either food or ethanol was the only programmed reinforcement available during each component. Fluvoxamine was less potent at decreasing ethanol self-administration when food was available concurrently {ED50 [95% confidence limit (CL): 8.2 (6.5-10.3) and 10.7 (7.9-14.4)]} versus when ethanol was available in isolation [ED50: 4.0 (2.7-5.9) and 5.1 (4.3-6.0)]. Effects on food were similar under each condition in which food was available. The results demonstrate that the potency of fluvoxamine in reducing ethanol-maintained behavior depends on whether ethanol is available in isolation or in the context of concurrently scheduled food reinforcement.

Matching: Its Acquisition and Generalization

ERIC Educational Resources Information Center

Crowley, Michael A.; Donahoe, John W.

2004-01-01

Choice typically is studied by exposing organisms to concurrent variable-interval schedules in which not only responses controlled by stimuli on the key are acquired but also switching responses and likely other operants as well. In the present research, discriminated key-pecking responses in pigeons were first acquired using a multiple schedule…

Do Conditional Reinforcers Count?

ERIC Educational Resources Information Center

Davison, Michael; Baum, William M.

2006-01-01

Six pigeons were trained on a procedure in which seven components arranged different food-delivery ratios on concurrent variable-interval schedules each session. The components were unsignaled, lasted for 10 food deliveries, and occurred in random order with a 60-s blackout between components. The schedules were arranged using a switching-key…

BIOPHYSICAL CHARACTERISATION OF THE UNDER-APPRECIATED AND IMPORTANT RELATIONSHIP BETWEEN HEART RATE VARIABILITY AND HEART RATE

PubMed Central

Monfredi, Oliver; Lyashkov, Alexey E; Johnsen, Anne-Berit; Inada, Shin; Schneider, Heiko; Wang, Ruoxi; Nirmalan, Mahesh; Wisloff, Ulrik; Maltsev, Victor A; Lakatta, Edward G; Zhang, Henggui; Boyett, Mark R

2014-01-01

Heart rate variability (beat-to-beat changes in the RR interval) has attracted considerable attention over the last 30+ years (PubMed currently lists >17,000 publications). Clinically, a decrease in heart rate variability is correlated to higher morbidity and mortality in diverse conditions, from heart disease to foetal distress. It is usually attributed to fluctuation in cardiac autonomic nerve activity. We calculated heart rate variability parameters from a variety of cardiac preparations (including humans, living animals, Langendorff-perfused heart and single sinoatrial nodal cell) in diverse species, combining this with data from previously published papers. We show that regardless of conditions, there is a universal exponential decay-like relationship between heart rate variability and heart rate. Using two biophysical models, we develop a theory for this, and confirm that heart rate variability is primarily dependent on heart rate and cannot be used in any simple way to assess autonomic nerve activity to the heart. We suggest that the correlation between a change in heart rate variability and altered morbidity and mortality is substantially attributable to the concurrent change in heart rate. This calls for re-evaluation of the findings from many papers that have not adjusted properly or at all for heart rate differences when comparing heart rate variability in multiple circumstances. PMID:25225208

Asymmetry of Reinforcement and Punishment in Human Choice

ERIC Educational Resources Information Center

Rasmussen, Erin B.; Newland, M. Christopher

2008-01-01

The hypothesis that a penny lost is valued more highly than a penny earned was tested in human choice. Five participants clicked a computer mouse under concurrent variable-interval schedules of monetary reinforcement. In the no-punishment condition, the schedules arranged monetary gain. In the punishment conditions, a schedule of monetary loss was…

EPIC Computational Models of Psychological Refractory-Period Effects in Human Multiple-Task Performance.

ERIC Educational Resources Information Center

Meyer, David E.; Kieras, David E.

Perceptual-motor and cognitive processes whereby people perform multiple concurrent tasks have been studied through an overlapping-tasks procedure in which two successive choice-reaction tasks are performed with a variable interval (stimulus onset asynchrony, or SOA) between the beginning of the first and second tasks. The increase in subjects'…

Dose-dependent heart rate reducing effect of nizatidine, a histamine H2-receptor antagonist.

PubMed Central

Hinrichsen, H; Halabi, A; Fuhrmann, G; Kirch, W

1993-01-01

1. Twelve healthy subjects were treated in a randomised placebo-controlled crossover study with placebo, 150 mg, 300 mg, and 600 mg nizatidine, 100 mg pirenzepine, and 300 mg nizatidine plus 100 mg pirenzepine for 1 week each. 2. On the seventh treatment day, heart rate, blood pressure, systolic time intervals, impedance cardiographic and Doppler ultrasound variables were measured. 3. Stroke volume and blood pressure were not altered by nizatidine and/or pirenzepine. By contrast, heart rate and cardiac output significantly (P < 0.05) decreased in a dose-dependent manner 1.5 and 3 h after administration of 300 and 600 mg nizatidine. Treatment with 150 mg nizatidine led to similar though non-significant trends. 4. While a slightly insignificant rise in heart rate was detected with pirenzepine alone, heart rate and cardiac output remained unchanged upon combined nizatidine and pirenzepine treatment as compared with placebo and baseline values. 5. In conclusion, nizatidine reduced heart rate and cardiac output in a dose-dependent manner, whereas this negative chronotropic effect was counteracted by concurrent administration of the anti-cholinergic drug pirenzepine. PMID:8099802

Client Perceptions of Helpfulness in Therapy: a Novel Video-Rating Methodology for Examining Process Variables at Brief Intervals During a Single Session.

PubMed

Cocklin, Alexandra A; Mansell, Warren; Emsley, Richard; McEvoy, Phil; Preston, Chloe; Comiskey, Jody; Tai, Sara

2017-11-01

The value of clients' reports of their experiences in therapy is widely recognized, yet quantitative methodology has rarely been used to measure clients' self-reported perceptions of what is helpful over a single session. A video-rating method using was developed to gather data at brief intervals using process measures of client perceived experience and standardized measures of working alliance (Session Rating Scale; SRS). Data were collected over the course of a single video-recorded session of cognitive therapy (Method of Levels Therapy; Carey, 2006; Mansell et al., 2012). We examined the acceptability and feasibility of the methodology and tested the concurrent validity of the measure by utilizing theory-led constructs. Eighteen therapy sessions were video-recorded and clients each rated a 20-minute session of therapy at two-minute intervals using repeated measures. A multi-level analysis was used to test for correlations between perceived levels of helpfulness and client process variables. The design proved to be feasible. Concurrent validity was borne out through high correlations between constructs. A multi-level regression examined the independent contributions of client process variables to client perceived helpfulness. Client perceived control (b = 0.39, 95% CI .05 to 0.73), the ability to talk freely (b = 0.30, SE = 0.11, 95% CI .09 to 0.51) and therapist approach (b = 0.31, SE = 0.14, 95% CI .04 to 0.57) predicted client-rated helpfulness. We identify a feasible and acceptable method for studying continuous measures of helpfulness and their psychological correlates during a single therapy session.

Gait performance is not influenced by working memory when walking at a self-selected pace.

PubMed

Grubaugh, Jordan; Rhea, Christopher K

2014-02-01

Gait performance exhibits patterns within the stride-to-stride variability that can be indexed using detrended fluctuation analysis (DFA). Previous work employing DFA has shown that gait patterns can be influenced by constraints, such as natural aging or disease, and they are informative regarding a person's functional ability. Many activities of daily living require concurrent performance in the cognitive and gait domains; specifically working memory is commonly engaged while walking, which is considered dual-tasking. It is unknown if taxing working memory while walking influences gait performance as assessed by DFA. This study used a dual-tasking paradigm to determine if performance decrements are observed in gait or working memory when performed concurrently. Healthy young participants (N = 16) performed a working memory task (automated operation span task) and a gait task (walking at a self-selected speed on a treadmill) in single- and dual-task conditions. A second dual-task condition (reading while walking) was included to control for visual attention, but also introduced a task that taxed working memory over the long term. All trials involving gait lasted at least 10 min. Performance in the working memory task was indexed using five dependent variables (absolute score, partial score, speed error, accuracy error, and math error), while gait performance was indexed by quantifying the mean, standard deviation, and DFA α of the stride interval time series. Two multivariate analyses of variance (one for gait and one for working memory) were used to examine performance in the single- and dual-task conditions. No differences were observed in any of the gait or working memory dependent variables as a function of task condition. The results suggest the locomotor system is adaptive enough to complete a working memory task without compromising gait performance when walking at a self-selected pace.

Variation, Repetition, and Choice

ERIC Educational Resources Information Center

Abreu-Rodrigues, Josele; Lattal, Kennon A.; dos Santos, Cristiano V.; Matos, Ricardo A.

2005-01-01

Experiment 1 investigated the controlling properties of variability contingencies on choice between repeated and variable responding. Pigeons were exposed to concurrent-chains schedules with two alternatives. In the REPEAT alternative, reinforcers in the terminal link depended on a single sequence of four responses. In the VARY alternative, a…

Assessing the Role of Effort Reduction in the Reinforcing Efficacy of Timeout from Avoidance

ERIC Educational Resources Information Center

Galuska, Chad M.; Mikorski, Jeff; Perone, Michael

2012-01-01

Rats responded on concurrent schedules of shock-postponement or deletion (avoidance) and timeout from avoidance. In Experiment 1, 3 rats' responses on one lever postponed shocks for 20 s and responses on a second lever produced a 1-min timeout according to a variable-interval 45-s schedule. Across conditions, a warning signal (white noise) was…

Effect of current on the maximum possible reward.

PubMed

Gallistel, C R; Leon, M; Waraczynski, M; Hanau, M S

1991-12-01

Using a 2-lever choice paradigm with concurrent variable interval schedules of reward, it was found that when pulse frequency is increased, the preference-determining rewarding effect of 0.5-s trains of brief cathodal pulses delivered to the medial forebrain bundle of the rat saturates (stops increasing) at values ranging from 200 to 631 pulses/s (pps). Raising the current lowered the saturation frequency, which confirms earlier, more extensive findings showing that the rewarding effect of short trains saturates at pulse frequencies that vary from less than 100 pps to more than 800 pps, depending on the current. It was also found that the maximum possible reward--the magnitude of the reward at or beyond the saturation pulse frequency--increases with increasing current. Thus, increasing the current reduces the saturation frequency but increases the subjective magnitude of the maximum possible reward.

Effects of conditioned reinforcement frequency in an intermittent free-feeding situation, 12

PubMed Central

Zimmerman, Joseph; Hanford, Peter V.; Brown, Wyman

1967-01-01

Key-pecking intermittently produced a set of brief exteroceptive stimulus changes under two-component multiple schedules of conditioned reinforcement. Throughout the study, free access to grain was concurrently provided on an intermittent basis via a variable-interval tape. Free food presentations scheduled by the tape were delivered if no peck had been emitted for 6 sec, and the brief stimulus changes produced by responding under the multiple schedules were those which accompanied food presentation. The second component of each multiple schedule was always associated with a 1-min, variable-interval schedule of conditioned reinforcement. The schedule associated with the first component was systematically varied and conditioned reinforcement was either absent (extinction) or programmed on a 1-, 3-, 6-, or 12-min variable-interval schedule. Under these conditions, rate of responding in the manipulated component decreased monotonically with a decrease in the frequency of conditioned reinforcement. In addition, contrast effects were often obtained in the constant, second component. These results are similar to those obtained with similar multiple schedules of primary reinforcement. PMID:6033554

Verification of Concurrent Programs. Part II. Temporal Proof Principles.

DTIC Science & Technology

1981-09-01

not modify any of the shared program variables. In order to ensure the correct synchronization between the processes we use three semaphore variables...direct, simple, and intuitive rides for the establishment of these properties. rhey usually replace long but repetitively similar chains of primitive ...modify the variables on which Q actually depends. A typical case is that of semaphores . We have the following property: The Semaphore Variable Rule

The rat approximates an ideal detector of changes in rates of reward: implications for the law of effect.

PubMed

Gallistel, C R; Mark, T A; King, A P; Latham, P E

2001-10-01

Rats responded on 2 levers delivering brain stimulation reward on concurrent variable interval schedules. Following many successive sessions with unchanging relative rates of reward, subjects adjusted to an eventual change slowly and showed spontaneous reversions at the beginning of subsequent sessions. When changes in rates of reward occurred between and within every session, subjects adjusted to them about as rapidly as they could in principle do so, as shown by comparison to a Bayesian model of an ideal detector. This and other features of the adjustments to frequent changes imply that the behavioral effect of reinforcement depends on the subject's perception of incomes and changes in incomes rather than on the strengthening and weakening of behaviors in accord with their past effects or expected results. Models for the process by which perceived incomes determine stay durations and for the process that detects changes in rates are developed.

Secondary reinforcement and number of primary reinforcements1

PubMed Central

Fantino, Edmund; Herrnstein, R. J.

1968-01-01

Pigeons' pecks on either of two concurrently available response keys produced secondary reinforcers according to independent one-minute variable-interval schedules. Different secondary reinforcers, in the presence of which the rates of primary reinforcement were equal, were associated with each key. The rate of pecking maintained by each secondary reinforcer varied directly, but nonproportionally, with the number of primary reinforcements given in the presence of the secondary reinforcer. PMID:5636860

Discrimination of Variable Schedules Is Controlled by Interresponse Times Proximal to Reinforcement

ERIC Educational Resources Information Center

Tanno, Takayuki; Silberberg, Alan; Sakagami, Takayuki

2012-01-01

In Experiment 1, food-deprived rats responded to one of two schedules that were, with equal probability, associated with a sample lever. One schedule was always variable ratio, while the other schedule, depending on the trial within a session, was: (a) a variable-interval schedule; (b) a tandem variable-interval,…

Study on multi-satellite, multi-measurement of the structure of the earth's bow shock

NASA Technical Reports Server (NTRS)

1972-01-01

The pulsation model of the earth's bow shock proposed a nonuniform shock having both perpendicular (abrupt, monotonic) and oblique (oscillatory, multigradient) properties simultaneously, depending on local orientation of the shock surface to the interplanetary field B sub sw in parallel planes defined by B sub sw and solar wind velocity. Multiple, concurrent, satellite observations of the shock and solar wind conditions were used. Twenty-six potentially useful intervals of concurrent Explorer 33 and 35 data acquisition were examined, of which six were selected for closer study. In addition, two years of OGO-5 and HEOS 1 magnetometer data were examined for possible conjunctions to these spacecraft having applicable data. One case of clear nonuniformity and several of field-dependent structure were documented. A computational aid, called pulsation index, was developed.

Scale Dependence of Oak Woodland Historical Fire Intervals: Contrasting the Barrens of Tennessee and Cross Timbers of Oklahoma, USA

Treesearch

Michael C. Stambaugh; Richard P. Guyette; Joseph M. Marschall; Daniel C. Dey

2016-01-01

Characterization of scale dependence of fire intervals could inform interpretations of fire history and improve fire prescriptions that aim to mimic historical fire regime conditions. We quantified the temporal variability in fire regimes and described the spatial dependence of fire intervals through the analysis of multi-century fire scar records (8 study sites, 332...

Obese and Lean Zucker Rats Demonstrate Differential Sensitivity to Rates of Food Reinforcement in a Choice Procedure

PubMed Central

Buckley, Jessica L.; Rasmussen, Erin B.

2012-01-01

The obese Zucker rat carries two recessive fa alleles that result in the expression of an obese phenotype. Obese Zuckers have higher food intake than lean controls in free-feed studies in which rats have ready access to a large amount of one type of food. The present study examined differences in obese and lean Zucker rats using concurrent schedules of reinforcement, which more ecologically models food selection using two food choices that have limited, but generally predictable, availability. Lever-pressing of ten lean (Fa/Fa or Fa/fa) and ten obese (fa/fa) Zucker rats was placed under three concurrent variable interval variable interval (conc VI VI) schedules of sucrose and carrot reinforcement, in which the reinforcer ratios for 45-mg food pellets were 5:1, 1:1, and 1:5. Allocation of responses to the two food alternatives was characterized using the generalized matching equation, which allows sensitivity to reinforcer rates (a) and bias toward one alternative (log k) to be quantified. All rats showed a bias to sucrose, though there were no differences between lean and obese Zucker rats. In addition, obese Zucker rats exhibited higher sensitivity to reinforcement rates than lean rats. This efficient pattern of responding was related to overall higher deliveries of food pellets. Effective matching for food, then, may be another behavioral pattern that contributes to an obese phenotype. PMID:23046726

Concurrent schedules of wheel-running reinforcement: choice between different durations of opportunity to run in rats.

PubMed

Belke, Terry W

2006-02-01

How do animals choose between opportunities to run of different durations? Are longer durations preferred over shorter durations because they permit a greater number of revolutions? Are shorter durations preferred because they engender higher rates of running? Will longer durations be chosen because running is less constrained? The present study reports on three experiments that attempted to address these questions. In the first experiment, five male Wistar rats chose between 10-sec and 50-sec opportunities to run on modified concurrent variable-interval (VI) schedules. Across conditions, the durations associated with the alternatives were reversed. Response, time, and reinforcer proportions did not vary from indifference. In a second experiment, eight female Long-Evans rats chose between opportunities to run of equal (30 sec) and unequal durations (10 sec and 50 sec) on concurrent variable-ratio (VR) schedules. As in Experiment 1, between presentations of equal duration conditions, 10-sec and 50-sec durations were reversed. Results showed that response, time, and reinforcer proportions on an alternative did not vary with reinforcer duration. In a third experiment, using concurrent VR schedules, durations were systematically varied to decrease the shorter duration toward 0 sec. As the shorter duration decreased, response, time, and reinforcer proportions shifted toward the longer duration. In summary, differences in durations of opportunities to run did not affect choice behavior in a manner consistent with the assumption that a longer reinforcer is a larger reinforcer.

Synaesthesia: when coloured sounds taste sweet.

PubMed

Beeli, Gian; Esslen, Michaela; Jäncke, Lutz

2005-03-03

Synaesthesia is the involuntary physical experience of a cross-modal linkage--for example, hearing a tone (the inducing stimulus) evokes an additional sensation of seeing a colour (concurrent perception). Of the different types of synaesthesia, most have colour as the concurrent perception, with concurrent perceptions of smell or taste being rare. Here we describe the case of a musician who experiences different tastes in response to hearing different musical tone intervals, and who makes use of her synaesthetic sensations in the complex task of tone-interval identification. To our knowledge, this combination of inducing stimulus and concurrent perception has not been described before.

Delta Ori Phase-Dependent Variability from Chandra and MOST Campaign

NASA Astrophysics Data System (ADS)

Nichols, Joy; Naze, Yael; Moffatt, Anthony F. J.; Corcoran, Michael; Richardson, Noel; Williams, S.; Pollock, A. M. T.; Ignace, Richard; Hole, T.; Waldron, W.; Evans, Nancy Remage; MOST Collaboration

2013-06-01

We report preliminary results from variability analysis of delta Ori in Chandra high-resolution X-ray spectroscopy and concurrent MOST high-precision optical photometry. With nearly complete phase coverage of the 5-day eclipsing binary orbit, it is possible to measure directly radial velocity and flux variations as a function of phase, leading to a mapping of the stellar wind distribution for the massive primary star. The phase dependence of the X-ray overall intensity and the comparative behavior of the emission lines are also presented.

Indifference between punishment and free shock: evidence for the negative law of effect1

PubMed Central

Schuster, Richard; Rachlin, Howard

1968-01-01

Pigeons were trained to respond under two conditions with two identical variable-interval schedules of positive reinforcement. While the schedules operated for separate response keys, they were not available concurrently. During one condition, each response was punished with electric shock. During the other condition, shocks were delivered independently of responding. The punishment suppressed responding but the free shocks did not. However, when allowed to choose, the pigeons preferred the condition associated with the lowest rate of shock regardless of whether or not the shock was dependent on responding. In general, shocks exerted their greatest effect on whichever response had the greatest influence on shocks. In this respect, punishment is instrumental in suppressing behavior and the properties of punishment are symmetrical to those of reinforcement. This empirical symmetry dictates a corresponding conceptual symmetry in terms of a positive law of effect accounting for response increments and a negative law accounting for response decrements. PMID:16811322

Hysteresis in simulations of malaria transmission

NASA Astrophysics Data System (ADS)

Yamana, Teresa K.; Qiu, Xin; Eltahir, Elfatih A. B.

2017-10-01

Malaria transmission is a complex system and in many parts of the world is closely related to climate conditions. However, studies on environmental determinants of malaria generally consider only concurrent climate conditions and ignore the historical or initial conditions of the system. Here, we demonstrate the concept of hysteresis in malaria transmission, defined as non-uniqueness of the relationship between malaria prevalence and concurrent climate conditions. We show the dependence of simulated malaria transmission on initial prevalence and the initial level of human immunity in the population. Using realistic time series of environmental variables, we quantify the effect of hysteresis in a modeled population. In a set of numerical experiments using HYDREMATS, a field-tested mechanistic model of malaria transmission, the simulated maximum malaria prevalence depends on both the initial prevalence and the initial level of human immunity in the population. We found the effects of initial conditions to be of comparable magnitude to the effects of interannual variability in environmental conditions in determining malaria prevalence. The memory associated with this hysteresis effect is longer in high transmission settings than in low transmission settings. Our results show that efforts to simulate and forecast malaria transmission must consider the exposure history of a location as well as the concurrent environmental drivers.

Evaluation of confidence intervals for a steady-state leaky aquifer model

USGS Publications Warehouse

Christensen, S.; Cooley, R.L.

1999-01-01

The fact that dependent variables of groundwater models are generally nonlinear functions of model parameters is shown to be a potentially significant factor in calculating accurate confidence intervals for both model parameters and functions of the parameters, such as the values of dependent variables calculated by the model. The Lagrangian method of Vecchia and Cooley [Vecchia, A.V. and Cooley, R.L., Water Resources Research, 1987, 23(7), 1237-1250] was used to calculate nonlinear Scheffe-type confidence intervals for the parameters and the simulated heads of a steady-state groundwater flow model covering 450 km2 of a leaky aquifer. The nonlinear confidence intervals are compared to corresponding linear intervals. As suggested by the significant nonlinearity of the regression model, linear confidence intervals are often not accurate. The commonly made assumption that widths of linear confidence intervals always underestimate the actual (nonlinear) widths was not correct. Results show that nonlinear effects can cause the nonlinear intervals to be asymmetric and either larger or smaller than the linear approximations. Prior information on transmissivities helps reduce the size of the confidence intervals, with the most notable effects occurring for the parameters on which there is prior information and for head values in parameter zones for which there is prior information on the parameters.The fact that dependent variables of groundwater models are generally nonlinear functions of model parameters is shown to be a potentially significant factor in calculating accurate confidence intervals for both model parameters and functions of the parameters, such as the values of dependent variables calculated by the model. The Lagrangian method of Vecchia and Cooley was used to calculate nonlinear Scheffe-type confidence intervals for the parameters and the simulated heads of a steady-state groundwater flow model covering 450 km2 of a leaky aquifer. The nonlinear confidence intervals are compared to corresponding linear intervals. As suggested by the significant nonlinearity of the regression model, linear confidence intervals are often not accurate. The commonly made assumption that widths of linear confidence intervals always underestimate the actual (nonlinear) widths was not correct. Results show that nonlinear effects can cause the nonlinear intervals to be asymmetric and either larger or smaller than the linear approximations. Prior information on transmissivities helps reduce the size of the confidence intervals, with the most notable effects occurring for the parameters on which there is prior information and for head values in parameter zones for which there is prior information on the parameters.

Preference pulses and the win-stay, fix-and-sample model of choice.

PubMed

Hachiga, Yosuke; Sakagami, Takayuki; Silberberg, Alan

2015-11-01

Two groups of six rats each were trained to respond to two levers for a food reinforcer. One group was trained on concurrent variable-ratio 20 extinction schedules of reinforcement. The second group was trained on a concurrent variable-interval 27-s extinction schedule. In both groups, lever-schedule assignments changed randomly following reinforcement; a light cued the lever providing the next reinforcer. In the next condition, the light cue was removed and reinforcer assignment strictly alternated between levers. The next two conditions redetermined, in order, the first two conditions. Preference pulses, defined as a tendency for relative response rate to decline to the just-reinforced alternative with time since reinforcement, only appeared during the extinction schedule. Although the pulse's functional form was well described by a reinforcer-induction equation, there was a large residual between actual data and a pulse-as-artifact simulation (McLean, Grace, Pitts, & Hughes, 2014) used to discern reinforcer-dependent contributions to pulsing. However, if that simulation was modified to include a win-stay tendency (a propensity to stay on the just-reinforced alternative), the residual was greatly reduced. Additional modifications of the parameter values of the pulse-as-artifact simulation enabled it to accommodate the present results as well as those it originally accommodated. In its revised form, this simulation was used to create a model that describes response runs to the preferred alternative as terminating probabilistically, and runs to the unpreferred alternative as punctate with occasional perseverative response runs. After reinforcement, choices are modeled as returning briefly to the lever location that had been just reinforced. This win-stay propensity is hypothesized as due to reinforcer induction. © Society for the Experimental Analysis of Behavior.

Accurate and consistent automatic seismocardiogram annotation without concurrent ECG.

PubMed

Laurin, A; Khosrow-Khavar, F; Blaber, A P; Tavakolian, Kouhyar

2016-09-01

Seismocardiography (SCG) is the measurement of vibrations in the sternum caused by the beating of the heart. Precise cardiac mechanical timings that are easily obtained from SCG are critically dependent on accurate identification of fiducial points. So far, SCG annotation has relied on concurrent ECG measurements. An algorithm capable of annotating SCG without the use any other concurrent measurement was designed. We subjected 18 participants to graded lower body negative pressure. We collected ECG and SCG, obtained R peaks from the former, and annotated the latter by hand, using these identified peaks. We also annotated the SCG automatically. We compared the isovolumic moment timings obtained by hand to those obtained using our algorithm. Mean  ±  confidence interval of the percentage of accurately annotated cardiac cycles were [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text] for levels of negative pressure 0, -20, -30, -40, and  -50 mmHg. LF/HF ratios, the relative power of low-frequency variations to high-frequency variations in heart beat intervals, obtained from isovolumic moments were also compared to those obtained from R peaks. The mean differences  ±  confidence interval were [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text] for increasing levels of negative pressure. The accuracy and consistency of the algorithm enables the use of SCG as a stand-alone heart monitoring tool in healthy individuals at rest, and could serve as a basis for an eventual application in pathological cases.

Parallel scheduling of recursively defined arrays

NASA Technical Reports Server (NTRS)

Myers, T. J.; Gokhale, M. B.

1986-01-01

A new method of automatic generation of concurrent programs which constructs arrays defined by sets of recursive equations is described. It is assumed that the time of computation of an array element is a linear combination of its indices, and integer programming is used to seek a succession of hyperplanes along which array elements can be computed concurrently. The method can be used to schedule equations involving variable length dependency vectors and mutually recursive arrays. Portions of the work reported here have been implemented in the PS automatic program generation system.

The Effects of a Local Negative Feedback Function between Choice and Relative Reinforcer Rate

PubMed Central

Davison, Michael; Elliffe, Douglas; Marr, M. Jackson

2010-01-01

Four pigeons were trained on two-key concurrent variable-interval schedules with no changeover delay. In Phase 1, relative reinforcers on the two alternatives were varied over five conditions from .1 to .9. In Phases 2 and 3, we instituted a molar feedback function between relative choice in an interreinforcer interval and the probability of reinforcers on the two keys ending the next interreinforcer interval. The feedback function was linear, and was negatively sloped so that more extreme choice in an interreinforcer interval made it more likely that a reinforcer would be available on the other key at the end of the next interval. The slope of the feedback function was −1 in Phase 2 and −3 in Phase 3. We varied relative reinforcers in each of these phases by changing the intercept of the feedback function. Little effect of the feedback functions was discernible at the local (interreinforcer interval) level, but choice measured at an extended level across sessions was strongly and significantly decreased by increasing the negative slope of the feedback function. PMID:21451748

CALCULATION OF NONLINEAR CONFIDENCE AND PREDICTION INTERVALS FOR GROUND-WATER FLOW MODELS.

USGS Publications Warehouse

Cooley, Richard L.; Vecchia, Aldo V.

1987-01-01

A method is derived to efficiently compute nonlinear confidence and prediction intervals on any function of parameters derived as output from a mathematical model of a physical system. The method is applied to the problem of obtaining confidence and prediction intervals for manually-calibrated ground-water flow models. To obtain confidence and prediction intervals resulting from uncertainties in parameters, the calibrated model and information on extreme ranges and ordering of the model parameters within one or more independent groups are required. If random errors in the dependent variable are present in addition to uncertainties in parameters, then calculation of prediction intervals also requires information on the extreme range of error expected. A simple Monte Carlo method is used to compute the quantiles necessary to establish probability levels for the confidence and prediction intervals. Application of the method to a hypothetical example showed that inclusion of random errors in the dependent variable in addition to uncertainties in parameters can considerably widen the prediction intervals.

CHARACTERISTICS OF MULTIPLE AND CONCURRENT PARTNERSHIPS AMONG WOMEN AT HIGH RISK FOR HIV INFECTION

PubMed Central

Adimora, Adaora A.; Hughes, James P.; Wang, Jing; Haley, Danielle F.; Golin, Carol E.; Magnus, Manya; Rompalo, Anne; Justman, Jessica; del Rio, Carlos; El-Sadr, Wafaa; Mannheimer, Sharon; Soto-Torres, Lydia; Hodder, Sally L.

2014-01-01

Objectives We examined parameters of sexual partnerships, including respondents’ participation in concurrency, belief that their partner had concurrent partnerships (partners’ concurrency), and partnership intervals, among the 2,099 women in HIV Prevention Trials Network 064, a study of women at high risk for HIV infection, in ten US communities. Methods We analyzed baseline survey responses about partnership dates to determine prevalence of participants’ and partners’ concurrency, intervals between partnerships, knowledge of whether recent partner(s) had undergone HIV testing, and intercourse frequency during the preceding 6 months. Results Prevalence of participants’ and partners’ concurrency was 40% and 36% respectively; 24% of respondents had both concurrent partnerships and non-monogamous partners. Among women with >1 partner and no concurrent partnerships themselves, the median gap between partners was one month. Multiple episodes of unprotected vaginal intercourse with >2 of their most recent partners was reported by 60% of women who had both concurrent partnerships and non-monogamous partners, 50% with only concurrent partners and no partners’ concurrency, and 33% with only partners’ concurrency versus 14% of women with neither type of concurrency (p<.0001). Women who had any involvement with concurrency were also more likely than women with no concurrency involvement to report lack of awareness of whether recent partners had undergone HIV testing (participants’ concurrency 41%, partners’ concurrency 40%, both participants’ and partners’ concurrency 48%, neither 17%; p<.0001). Conclusions These network patterns and short gaps between partnerships may create substantial opportunities for HIV transmission in this sample of women at high risk for HIV infection. PMID:24056163

Including long-range dependence in integrate-and-fire models of the high interspike-interval variability of cortical neurons.

PubMed

Jackson, B Scott

2004-10-01

Many different types of integrate-and-fire models have been designed in order to explain how it is possible for a cortical neuron to integrate over many independent inputs while still producing highly variable spike trains. Within this context, the variability of spike trains has been almost exclusively measured using the coefficient of variation of interspike intervals. However, another important statistical property that has been found in cortical spike trains and is closely associated with their high firing variability is long-range dependence. We investigate the conditions, if any, under which such models produce output spike trains with both interspike-interval variability and long-range dependence similar to those that have previously been measured from actual cortical neurons. We first show analytically that a large class of high-variability integrate-and-fire models is incapable of producing such outputs based on the fact that their output spike trains are always mathematically equivalent to renewal processes. This class of models subsumes a majority of previously published models, including those that use excitation-inhibition balance, correlated inputs, partial reset, or nonlinear leakage to produce outputs with high variability. Next, we study integrate-and-fire models that have (nonPoissonian) renewal point process inputs instead of the Poisson point process inputs used in the preceding class of models. The confluence of our analytical and simulation results implies that the renewal-input model is capable of producing high variability and long-range dependence comparable to that seen in spike trains recorded from cortical neurons, but only if the interspike intervals of the inputs have infinite variance, a physiologically unrealistic condition. Finally, we suggest a new integrate-and-fire model that does not suffer any of the previously mentioned shortcomings. By analyzing simulation results for this model, we show that it is capable of producing output spike trains with interspike-interval variability and long-range dependence that match empirical data from cortical spike trains. This model is similar to the other models in this study, except that its inputs are fractional-gaussian-noise-driven Poisson processes rather than renewal point processes. In addition to this model's success in producing realistic output spike trains, its inputs have long-range dependence similar to that found in most subcortical neurons in sensory pathways, including the inputs to cortex. Analysis of output spike trains from simulations of this model also shows that a tight balance between the amounts of excitation and inhibition at the inputs to cortical neurons is not necessary for high interspike-interval variability at their outputs. Furthermore, in our analysis of this model, we show that the superposition of many fractional-gaussian-noise-driven Poisson processes does not approximate a Poisson process, which challenges the common assumption that the total effect of a large number of inputs on a neuron is well represented by a Poisson process.

On solving wave equations on fixed bounded intervals involving Robin boundary conditions with time-dependent coefficients

NASA Astrophysics Data System (ADS)

van Horssen, Wim T.; Wang, Yandong; Cao, Guohua

2018-06-01

In this paper, it is shown how characteristic coordinates, or equivalently how the well-known formula of d'Alembert, can be used to solve initial-boundary value problems for wave equations on fixed, bounded intervals involving Robin type of boundary conditions with time-dependent coefficients. A Robin boundary condition is a condition that specifies a linear combination of the dependent variable and its first order space-derivative on a boundary of the interval. Analytical methods, such as the method of separation of variables (SOV) or the Laplace transform method, are not applicable to those types of problems. The obtained analytical results by applying the proposed method, are in complete agreement with those obtained by using the numerical, finite difference method. For problems with time-independent coefficients in the Robin boundary condition(s), the results of the proposed method also completely agree with those as for instance obtained by the method of separation of variables, or by the finite difference method.

Kinetics of matching.

PubMed

Mark, T A; Gallistel, C R

1994-01-01

Rats responded on concurrent variable interval schedules of brain stimulation reward in 2-trial sessions. Between trials, there was a 16-fold reversal in the relative rate of reward. In successive, narrow time windows, the authors compared the ratio of the times spent on the 2 levers to the ratio of the rewards received. Time-allocation ratios tracked wide, random fluctuations in the reward ratio. The adjustment to the midsession reversal in relative rate of reward was largely completed within 1 interreward interval on the leaner schedule. Both results were unaffected by a 16-fold change in the combined rates of reward. The large, rapid, scale-invariant shifts in time-allocation ratios that underlie matching behavior imply that the subjective relative rate of reward can be determined by a very few of the most recent interreward intervals and that this estimate can directly determine the ratio of the expected stay durations.

Dependence of drivers affects risks associated with compound events

NASA Astrophysics Data System (ADS)

Zscheischler, Jakob; Seneviratne, Sonia I.

2017-04-01

Compound climate extremes are receiving increasing attention because of their disproportionate impacts on humans and ecosystems. Risks assessments, however, generally focus on univariate statistics even when multiple stressors are considered. Concurrent extreme droughts and heatwaves have been observed to cause a suite of extreme impacts on natural and human systems alike. For example, they can substantially affect vegetation health, prompting tree mortality, and thereby facilitating insect outbreaks and fires. In addition, hot droughts have the potential to trigger and intensify fires and can cause severe economical damage. By promoting disease spread, extremely hot and dry conditions also strongly affect human health. We analyse the co-occurrence of dry and hot summers and show that these are strongly correlated for many regions, inducing a much higher frequency of concurrent hot and dry summers than what would be assumed from the independent combination of the univariate statistics. Our results demonstrate how the dependence structure between variables affects the occurrence frequency of multivariate extremes. Assessments based on univariate statistics can thus strongly underestimate risks associated with given extremes, if impacts depend on multiple (dependent) variables. We conclude that a multivariate perspective is necessary in order to appropriately assess changes in climate extremes and their impacts, and to design adaptation strategies.

Exact Scheffé-type confidence intervals for output from groundwater flow models: 2. Combined use of hydrogeologic information and calibration data

USGS Publications Warehouse

Cooley, Richard L.

1993-01-01

Calibration data (observed values corresponding to model-computed values of dependent variables) are incorporated into a general method of computing exact Scheffé-type confidence intervals analogous to the confidence intervals developed in part 1 (Cooley, this issue) for a function of parameters derived from a groundwater flow model. Parameter uncertainty is specified by a distribution of parameters conditioned on the calibration data. This distribution was obtained as a posterior distribution by applying Bayes' theorem to the hydrogeologically derived prior distribution of parameters from part 1 and a distribution of differences between the calibration data and corresponding model-computed dependent variables. Tests show that the new confidence intervals can be much smaller than the intervals of part 1 because the prior parameter variance-covariance structure is altered so that combinations of parameters that give poor model fit to the data are unlikely. The confidence intervals of part 1 and the new confidence intervals can be effectively employed in a sequential method of model construction whereby new information is used to reduce confidence interval widths at each stage.

Rapid Acquisition of Preference in Concurrent Chains: Effects of "d"-Amphetamine on Sensitivity to Reinforcement Delay

ERIC Educational Resources Information Center

Ta, Wei-Min; Pitts, Raymond C.; Hughes, Christine E.; McLean, Anthony P.; Grace, Randolph C.

2008-01-01

The purpose of this study was to examine effects of "d"-amphetamine on choice controlled by reinforcement delay. Eight pigeons responded under a concurrent-chains procedure in which one terminal-link schedule was always fixed- interval 8 s, and the other terminal-link schedule changed from session to session between fixed-interval 4 s and…

Response rate and reinforcement rate in Pavlovian conditioning.

PubMed

Harris, Justin A; Carpenter, Joanne S

2011-10-01

Four experiments used delay conditioning of magazine approach in rats to investigate the relationship between the rate of responding, R, to a conditioned stimulus (CS) and the rate, r, at which the CS is reinforced with the unconditioned stimulus (US). Rats were concurrently trained with four variable-duration CSs with different rs, either as a result of differences in the mean CS-US interval or in the proportion of CS presentations that ended with the US. In each case, R was systematically related to r, and the relationship was very accurately characterized by a hyperbolic function, R = Ar/(r +c). Accordingly, the reciprocal of these two variables-response interval, I (= 1/R), and CS-US interval, i (= 1/r) - were related by a simple affine (straight line) transformation, I = mi+b. This latter relationship shows that each increment in the time that the rats had to wait for food produced a linear increment in the time they waited between magazine entries. We discuss the close agreement between our findings and the Matching Law (Herrnstein, 1970) and consider their implications for both associative theories (e.g., Rescorla & Wagner, 1972) and nonassociative theories (Gallistel & Gibbon, 2000) of conditioning. (PsycINFO Database Record (c) 2011 APA, all rights reserved).

Analysis of backward error recovery for concurrent processes with recovery blocks

NASA Technical Reports Server (NTRS)

Shin, K. G.; Lee, Y. H.

1982-01-01

Three different methods of implementing recovery blocks (RB's). These are the asynchronous, synchronous, and the pseudo recovery point implementations. Pseudo recovery points so that unbounded rollback may be avoided while maintaining process autonomy are proposed. Probabilistic models for analyzing these three methods under standard assumptions in computer performance analysis, i.e., exponential distributions for related random variables were developed. The interval between two successive recovery lines for asynchronous RB's mean loss in computation power for the synchronized method, and additional overhead and rollback distance in case PRP's are used were estimated.

Determinants of overweight with concurrent stunting among Ghanaian children.

PubMed

Atsu, Benedicta K; Guure, Chris; Laar, Amos K

2017-07-27

Malnutrition (undernutrition and overnutrition) is a major public health problem in Ghana -affecting growth and development of individuals and the nation. Stunting and overweight are of particular interest, as recent national surveys show a rising trend of overnutrition and stubbornly high burden of stunting among Ghanaian children. There are currently no data on the simultaneous occurrence of overweight and stunting within individuals in Ghana. This paper presents the burden, the individual-level, and contextual determinants of overweight with concurrent stunting among Ghanaian children. This study analyzed data set of the fourth round of the Ghana Multiple Indicator Cluster Survey (MICS4). Bivariate analyses were used to describe selected characteristics of survey respondents and their children. Hierarchical modelling approach facilitated identification of significant distal, intermediate and proximal factors/determinants of concurrent stunting and overweight. Both crude and adjusted prevalence ratios via a multivariable Poison regression model with their corresponding 95% Confidence Intervals (CI) are reported. Variables with p ≤ 0.25 at the bivariate level were included in the multivariable analysis. An alpha value of 5% was used to indicate significance. Of 7550 cases (children) analyzed, the prevalence of stunting was 27.5%; underweight was 17.3%; and wasting was 7.7%. The prevalence of overweight and concurrent overweight and stunting were respectively 2.4% and 1.2%. Children who belonged to the fourth wealth quintile, were more likely to be overweight and concurrently stunted as against children belonging to the poorest quintile (aPR = 1.010; 95% CI, 1.003-1.017). Compared to religious (Christians/Muslim/Traditionalist) household heads, children whose household heads did not belong to any religion had 2 times the rates of the Overweight with concurrent stunting (PR = 2.024; 95% CI, 1.016-4.034). Children with mothers aged 20-34 and 35-49 had an increased though insignificant prevalence ratio of association (aPR = 1.001; 95% CI, 0.994-1.005) and (aPR = 1.001; 95% CI, 0.998-1.012) respectively. This analysis determined the prevalence of concurrent stunting and overweight among Ghanaian children to be 1.2%. Four contextual variables (breastfeeding status, religion, geographic region, and wealth index quintile) were associated with overweight with concurrent stunting. We conclude that, only contextual factors are predictive of DBM among children under five living in Ghana.

Resistance to reinforcement change in multiple and concurrent schedules assessed in transition and at steady state.

PubMed

McLean, A P; Blampied, N M

1995-01-01

Behavioral momentum theory relates resistance to change of responding in a multiple-schedule component to the total reinforcement obtained in that component, regardless of how the reinforcers are produced. Four pigeons responded in a series of multiple-schedule conditions in which a variable-interval 40-s schedule arranged reinforcers for pecking in one component and a variable-interval 360-s schedule arranged them in the other. In addition, responses on a second key were reinforced according to variable-interval schedules that were equal in the two components. In different parts of the experiment, responding was disrupted by changing the rate of reinforcement on the second key or by delivering response-independent food during a blackout separating the two components. Consistent with momentum theory, responding on the first key in Part 1 changed more in the component with the lower reinforcement total when it was disrupted by changes in the rate of reinforcement on the second key. However, responding on the second key changed more in the component with the higher reinforcement total. In Parts 2 and 3, responding was disrupted with free food presented during intercomponent blackouts, with extinction (Part 2) or variable-interval 80-s reinforcement (Part 3) arranged on the second key. Here, resistance to change was greater for the component with greater overall reinforcement. Failures of momentum theory to predict short-term differences in resistance to change occurred with disruptors that caused greater change between steady states for the richer component. Consistency of effects across disruptors may yet be found if short-term effects of disruptors are assessed relative to the extent of change observed after prolonged exposure.

Punishment and the potential for negative reinforcement with histamine injection.

PubMed

Mayer, Paulo César Morales; de Carvalho Neto, Marcus Bentes; Katz, Jonathan L

2018-03-01

The present study examined punishment of responding with histamine injection, and its potential to generate avoidance of punishment. Sprague-Dawley rats were trained under concurrent schedules in which responses on one lever (the punishment lever) produced food under a variable-interval schedule, and under some conditions intermittent injections of histamine, which suppressed behavior. Responses on a second (avoidance) lever prevented histamine injections scheduled on the punishment lever. After stabilization of punished responding, a variable-interval 15-s schedule of cancellation of histamine (avoidance) was added for responding on the second/avoidance lever, without subsequent acquisition of responding on that lever. Progressive decreases in the length of the punishment variable-interval schedule increased suppression on the punishment lever without increases in response rates on the avoidance lever. Exchanging contingencies on the levers ensured that response rates on the avoidance lever were sufficiently high to decrease the histamine injection frequency; nonetheless response rates on the avoidance lever decreased over subsequent sessions. Under no condition was responding maintained on the avoidance lever despite continued punishing effectiveness of histamine throughout. The present results suggest that avoidance conditioning is not a necessary condition for effective punishment, and confirm the importance of empirical rather than presumed categorization of behavioral effects of stimulus events. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

Multiple endocrine diseases in cats: 15 cases (1997-2008).

PubMed

Blois, Shauna L; Dickie, Erica L; Kruth, Stephen A; Allen, Dana G

2010-08-01

The objective of this retrospective study was to characterize a population of cats from a tertiary care center diagnosed with multiple endocrine disorders, including the specific disorders and time intervals between diagnosis of each disorder. Medical records of 15 cats diagnosed with more than one endocrine disorder were reviewed. The majority of cats were domestic shorthairs, and the mean age at the time of diagnosis of the first disorder was 10.3 years. The most common combination of disorders was diabetes mellitus and hyperthyroidism. Two cats had concurrent diabetes mellitus and hyperadrenocorticism, one cat had concurrent central diabetes insipidus and diabetes mellitus. A mean of 25.7 months elapsed between diagnoses of the first and second endocrine disorder, but this was variable. This study suggests the occurrence of multiple endocrine disorders is uncommon in cats. Copyright 2010 ISFM and AAFP. Published by Elsevier Ltd. All rights reserved.

A new variable interval schedule with constant hazard rate and finite time range.

PubMed

Bugallo, Mehdi; Machado, Armando; Vasconcelos, Marco

2018-05-27

We propose a new variable interval (VI) schedule that achieves constant probability of reinforcement in time while using a bounded range of intervals. By sampling each trial duration from a uniform distribution ranging from 0 to 2 T seconds, and then applying a reinforcement rule that depends linearly on trial duration, the schedule alternates reinforced and unreinforced trials, each less than 2 T seconds, while preserving a constant hazard function. © 2018 Society for the Experimental Analysis of Behavior.

Increased risk of concurrent hepatitis C among Male patients with schizophrenia.

PubMed

Chiu, Yu-Lung; Lin, Herng-Ching; Kao, Nai-Wen; Kao, Senyong; Lee, Hsin-Chien

2017-12-01

Prior studies attempted to explore the association between schizophrenia and hepatitis C virus (HCV). However, their conclusions were inconsistent. This study aimed to examine the association of schizophrenia with HCV using a population-based dataset in Taiwan. There were 6097 patients with schizophrenia and 6097 sex- and age-matched comparison patients without schizophrenia included in this study. We defined the dependent variable of interest as whether or not a patient had received a diagnosis of HCV. We found that of the sampled patients, 2.1% of patients with schizophrenia and 1.4% of comparison patients had concurrent HCV. We further found that schizophrenia was not significantly associated with concurrent HCV after adjusting for sex, age, urbanization level, geographic region, monthly income, and drug abuse. However, of the sampled male patients, the adjusted odds of concurrent hepatitis C for patients with schizophrenia were 1.72-times higher than the odds of concurrent HCV among comparison patients. We failed to observe this association among female sampled patients. We concluded that schizophrenia was not significantly associated with concurrent HCV. However, of the sampled male patients, the risk of concurrent HCV among patients with schizophrenia was higher than comparison patients. Copyright © 2017 Elsevier B.V. All rights reserved.

Day-to-Day Heart-Rate Variability Recordings in World-Champion Rowers: Appreciating Unique Athlete Characteristics.

PubMed

Plews, Daniel J; Laursen, Paul B; Buchheit, Martin

2017-05-01

Heart-rate variability (HRV) is a popular tool for monitoring autonomic nervous system status and training adaptation in athletes. It is believed that increases in HRV indicate effective training adaptation, but these are not always apparent in elite athletes. Resting HRV was recorded in 4 elite rowers (rowers A, B, C, and D) over the 7-wk period before their success at the 2015 World Rowing Championships. The natural logarithm of the square root of the mean sum of the squared differences (Ln rMSSD) between R-R intervals, Ln rMSSD:R-R ratio trends, and the Ln-rMSSD-to-R-R-interval relationship were assessed for each championship-winning rower. The time course of change in Ln rMSSD was athlete-dependent, with stagnation and decreases apparent. However, there were consistent substantial reductions in the Ln rMSSD:R-R ratio: rower A, baseline toward wk 5 (-2.35 ± 1.94); rower B, baseline to wk 4 and 5 (-0.41 ± 0.48 and -0.64 ± 0.65, respectively); rower C, baseline to wk 4 (-0.58 ± 0.66); and rower D, baseline to wk 4, 5, and 6 (-1.15 ± 0.91, -0.81 ± 0.74, and -1.43 ± 0.69, respectively). Reductions in Ln rMSSD concurrent with reductions in the Ln rMSSD:R-R ratio are indicative of parasympathetic saturation. Consequently, 3 of 4 rowers displayed substantial increases in parasympathetic activity despite having decreases in Ln rMSSD. These results confirm that a combination of indices should be used to monitor cardiac autonomic activity.

Concurrence of three Jaynes-Cummings systems

NASA Astrophysics Data System (ADS)

Qiang, Wen-Chao; Sun, Guo-Hua; Dong, Qian; Camacho-Nieto, Oscar; Dong, Shi-Hai

2018-04-01

We apply genuine multipartite concurrence to investigate entanglement properties of three Jaynes-Cummings systems. Three atoms are initially put in GHZ-like state and locally interact with three independent cavities, respectively. We present analytical concurrence expressions for various subsystems including three-atom, three-cavity and some atom-cavity mixed systems. We also examine the global system and illustrate the evolution of its concurrence. Except for the sudden death of entanglement, we find for some initial entanglement parameter θ , the concurrence of the global system may maintain unchanged in some time intervals.

Design approaches to experimental mediation☆

PubMed Central

Pirlott, Angela G.; MacKinnon, David P.

2016-01-01

Identifying causal mechanisms has become a cornerstone of experimental social psychology, and editors in top social psychology journals champion the use of mediation methods, particularly innovative ones when possible (e.g. Halberstadt, 2010, Smith, 2012). Commonly, studies in experimental social psychology randomly assign participants to levels of the independent variable and measure the mediating and dependent variables, and the mediator is assumed to causally affect the dependent variable. However, participants are not randomly assigned to levels of the mediating variable(s), i.e., the relationship between the mediating and dependent variables is correlational. Although researchers likely know that correlational studies pose a risk of confounding, this problem seems forgotten when thinking about experimental designs randomly assigning participants to levels of the independent variable and measuring the mediator (i.e., “measurement-of-mediation” designs). Experimentally manipulating the mediator provides an approach to solving these problems, yet these methods contain their own set of challenges (e.g., Bullock, Green, & Ha, 2010). We describe types of experimental manipulations targeting the mediator (manipulations demonstrating a causal effect of the mediator on the dependent variable and manipulations targeting the strength of the causal effect of the mediator) and types of experimental designs (double randomization, concurrent double randomization, and parallel), provide published examples of the designs, and discuss the strengths and challenges of each design. Therefore, the goals of this paper include providing a practical guide to manipulation-of-mediator designs in light of their challenges and encouraging researchers to use more rigorous approaches to mediation because manipulation-of-mediator designs strengthen the ability to infer causality of the mediating variable on the dependent variable. PMID:27570259

Design approaches to experimental mediation.

PubMed

Pirlott, Angela G; MacKinnon, David P

2016-09-01

Identifying causal mechanisms has become a cornerstone of experimental social psychology, and editors in top social psychology journals champion the use of mediation methods, particularly innovative ones when possible (e.g. Halberstadt, 2010, Smith, 2012). Commonly, studies in experimental social psychology randomly assign participants to levels of the independent variable and measure the mediating and dependent variables, and the mediator is assumed to causally affect the dependent variable. However, participants are not randomly assigned to levels of the mediating variable(s), i.e., the relationship between the mediating and dependent variables is correlational. Although researchers likely know that correlational studies pose a risk of confounding, this problem seems forgotten when thinking about experimental designs randomly assigning participants to levels of the independent variable and measuring the mediator (i.e., "measurement-of-mediation" designs). Experimentally manipulating the mediator provides an approach to solving these problems, yet these methods contain their own set of challenges (e.g., Bullock, Green, & Ha, 2010). We describe types of experimental manipulations targeting the mediator (manipulations demonstrating a causal effect of the mediator on the dependent variable and manipulations targeting the strength of the causal effect of the mediator) and types of experimental designs (double randomization, concurrent double randomization, and parallel), provide published examples of the designs, and discuss the strengths and challenges of each design. Therefore, the goals of this paper include providing a practical guide to manipulation-of-mediator designs in light of their challenges and encouraging researchers to use more rigorous approaches to mediation because manipulation-of-mediator designs strengthen the ability to infer causality of the mediating variable on the dependent variable.

Assessing Mediational Models: Testing and Interval Estimation for Indirect Effects

ERIC Educational Resources Information Center

Biesanz, Jeremy C.; Falk, Carl F.; Savalei, Victoria

2010-01-01

Theoretical models specifying indirect or mediated effects are common in the social sciences. An indirect effect exists when an independent variable's influence on the dependent variable is mediated through an intervening variable. Classic approaches to assessing such mediational hypotheses (Baron & Kenny, 1986; Sobel, 1982) have in recent years…

Saturn's dayside ultraviolet auroras: Evidence for morphological dependence on the direction of the upstream interplanetary magnetic field.

PubMed

Meredith, C J; Alexeev, I I; Badman, S V; Belenkaya, E S; Cowley, S W H; Dougherty, M K; Kalegaev, V V; Lewis, G R; Nichols, J D

2014-03-01

We examine a unique data set from seven Hubble Space Telescope (HST) "visits" that imaged Saturn's northern dayside ultraviolet emissions exhibiting usual circumpolar "auroral oval" morphologies, during which Cassini measured the interplanetary magnetic field (IMF) upstream of Saturn's bow shock over intervals of several hours. The auroras generally consist of a dawn arc extending toward noon centered near ∼15° colatitude, together with intermittent patchy forms at ∼10° colatitude and poleward thereof, located between noon and dusk. The dawn arc is a persistent feature, but exhibits variations in position, width, and intensity, which have no clear relationship with the concurrent IMF. However, the patchy postnoon auroras are found to relate to the (suitably lagged and averaged) IMF B z , being present during all four visits with positive B z and absent during all three visits with negative B z . The most continuous such forms occur in the case of strongest positive B z . These results suggest that the postnoon forms are associated with reconnection and open flux production at Saturn's magnetopause, related to the similarly interpreted bifurcated auroral arc structures previously observed in this local time sector in Cassini Ultraviolet Imaging Spectrograph data, whose details remain unresolved in these HST images. One of the intervals with negative IMF B z however exhibits a prenoon patch of very high latitude emission extending poleward of the dawn arc to the magnetic/spin pole, suggestive of the occurrence of lobe reconnection. Overall, these data provide evidence of significant IMF dependence in the morphology of Saturn's dayside auroras. We examine seven cases of joint HST Saturn auroral images and Cassini IMF dataThe persistent but variable dawn arc shows no obvious IMF dependencePatchy postnoon auroras are present for northward IMF but not for southward IMF.

Saturn's dayside ultraviolet auroras: Evidence for morphological dependence on the direction of the upstream interplanetary magnetic field

PubMed Central

Meredith, C J; Alexeev, I I; Badman, S V; Belenkaya, E S; Cowley, S W H; Dougherty, M K; Kalegaev, V V; Lewis, G R; Nichols, J D

2014-01-01

We examine a unique data set from seven Hubble Space Telescope (HST) “visits” that imaged Saturn's northern dayside ultraviolet emissions exhibiting usual circumpolar “auroral oval” morphologies, during which Cassini measured the interplanetary magnetic field (IMF) upstream of Saturn's bow shock over intervals of several hours. The auroras generally consist of a dawn arc extending toward noon centered near ∼15° colatitude, together with intermittent patchy forms at ∼10° colatitude and poleward thereof, located between noon and dusk. The dawn arc is a persistent feature, but exhibits variations in position, width, and intensity, which have no clear relationship with the concurrent IMF. However, the patchy postnoon auroras are found to relate to the (suitably lagged and averaged) IMF Bz, being present during all four visits with positive Bz and absent during all three visits with negative Bz. The most continuous such forms occur in the case of strongest positive Bz. These results suggest that the postnoon forms are associated with reconnection and open flux production at Saturn's magnetopause, related to the similarly interpreted bifurcated auroral arc structures previously observed in this local time sector in Cassini Ultraviolet Imaging Spectrograph data, whose details remain unresolved in these HST images. One of the intervals with negative IMF Bz however exhibits a prenoon patch of very high latitude emission extending poleward of the dawn arc to the magnetic/spin pole, suggestive of the occurrence of lobe reconnection. Overall, these data provide evidence of significant IMF dependence in the morphology of Saturn's dayside auroras. Key Points We examine seven cases of joint HST Saturn auroral images and Cassini IMF data The persistent but variable dawn arc shows no obvious IMF dependence Patchy postnoon auroras are present for northward IMF but not for southward IMF PMID:26167441

Intensified High-Dose Chemoradiotherapy With Induction Chemotherapy in Patients With Locally Advanced Non-Small-Cell Lung Cancer-Safety and Toxicity Results Within a Prospective Trial

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poettgen, Christoph, E-mail: christoph.poettgen@uk-essen.d; Eberhardt, Wilfried E.; Gauler, Thomas

2010-03-01

Purpose: To analyze the toxicity profile of an intensified definitive chemoradiotherapy (CRT) schedule in patients with locally advanced non-small-cell lung cancer (Stage IIIA N2/selected IIIB) treated within a prospective multicenter trial. Patients and Methods: After mediastinoscopy and routine staging procedures, three cycles of induction chemotherapy (cisplatin 50 mg/m{sup 2}, Days 1 and 8; paclitaxel 175 mg/m{sup 2} Day 1, every 21 days) were planned, followed by concurrent CRT (accelerated-hyperfractionated regimen, 45 Gy, 2 x 1.5 Gy/d, cisplatin 50 mg/m{sup 2}, Days 64 and 71, vinorelbine 20 mg/m{sup 2}, Days 64 and 71). At 45 Gy, a multidisciplinary panel decision wasmore » made regarding operability. Inoperable patients received definitive radiotherapy (total dose 65 or 71 Gy, depending on the mean lung dose) with additional concurrent chemotherapy (cisplatin 40 mg/m{sup 2}, Day 85; vinorelbine 15 mg/m{sup 2}, Days 85 and 92). Results: A total of 28 patients (23 men and 5 women; median age, 58 years; range 41-73; Stage IIIA in 3 and Stage IIIB in 25) were judged ineligible for surgery by the multidisciplinary panel and underwent definitive CRT (75% of the patients received 71 Gy). The maximum toxicity (Grade 3 or greater) during induction chemotherapy included leukopenia (11%) and anemia (4%). During concurrent CRT, leukopenia (Grade 3 or greater) was observed in 39% of the patients. The maximal nonhematologic toxicity during concurrent CRT included esophagitis (Grade 3 or greater) in 18% and pneumonitis (Grade 3 or greater) in 4% of the patients. At 3 years, the locoregional control rate was 52% (95% confidence interval, 29-75%) and the overall survival rate was 31% (95% confidence interval, 12-50%). Conclusion: This intensified treatment protocol with induction chemotherapy and concurrent CRT, including hyperfractionated-accelerated RT, showed only moderate toxicity and proved feasible. This treatment represents the definitive CRT arm of our ongoing multicenter randomized trial comparing definitive CRT and trimodality treatment.« less

The compatibility of concurrent high intensity interval training and resistance training for muscular strength and hypertrophy: a systematic review and meta-analysis.

PubMed

Sabag, Angelo; Najafi, Abdolrahman; Michael, Scott; Esgin, Tuguy; Halaki, Mark; Hackett, Daniel

2018-04-16

The purpose of this systematic review and meta-analysis is to assess the effect of concurrent high intensity interval training (HIIT) and resistance training (RT) on strength and hypertrophy. Five electronic databases were searched using terms related to HIIT, RT, and concurrent training. Effect size (ES), calculated as standardised differences in the means, were used to examine the effect of concurrent HIIT and RT compared to RT alone on muscle strength and hypertrophy. Sub-analyses were performed to assess region-specific strength and hypertrophy, HIIT modality (cycling versus running), and inter-modal rest responses. Compared to RT alone, concurrent HIIT and RT led to similar changes in muscle hypertrophy and upper body strength. Concurrent HIIT and RT resulted in a lower increase in lower body strength compared to RT alone (ES = -0.248, p = 0.049). Sub analyses showed a trend for lower body strength to be negatively affected by cycling HIIT (ES = -0.377, p = 0.074) and not running (ES = -0.176, p = 0.261). Data suggests concurrent HIIT and RT does not negatively impact hypertrophy or upper body strength, and that any possible negative effect on lower body strength may be ameliorated by incorporating running based HIIT and longer inter-modal rest periods.

Body weight concerns: Cross-national study and identification of factors related to eating disorders.

PubMed

Silva, Wanderson Roberto da; Santana, Moema de Souza; Maroco, João; Maloa, Benvindo Felismino Samuel; Campos, Juliana Alvares Duarte Bonini

2017-01-01

Body weight concerns are common among individuals with eating disorders, and this construct can be assessed using psychometric instruments. The Weight Concerns Scale (WCS) is commonly used to assess body weight concerns. To evaluate the psychometric properties of the WCS with Brazilian, Portuguese, and Mozambican female college students; to estimate body weight concerns; and to identify factors related to eating disorders. Confirmatory factor analysis was performed. Factorial, convergent, concurrent, and divergent validity, as well as reliability, were assessed. Cross-national invariance was tested by means of multigroup analysis. Structural models were tested using the WCS as the dependent variable, while demographic and academic variables and body mass index were used as independent variables. Logistic models were tested to estimate the likelihood of eating disorders being developed in specific groups. Participants were 2,068 female students. The psychometric properties of the WCS were adequate for the Portuguese sample; however, for the Brazilian and Mozambican samples, it was necessary to correlate the errors of two items to improve model fit. The WCS did not show cross-national invariance. The variables "thoughts about dropping out of college," "medication use because of studies," "medication and supplements use for body change," "body mass index," "socioeconomic status," "age," and "performance in course" were significant predictors of body weight concerns. Overall, 24.4% (95% confidence interval = 22.9-26.7) of the students were likely to develop eating disorders. Students under 21 years old, who use medication and supplements for body change, and who were classified as overweight/obese have increased likelihood of developing eating disorders. The WCS showed good psychometric properties with Brazilian, Portuguese, and Mozambican students; however, it did not show cross-national invariance. We identified important aspects for investigating body weight concerns and factors related to eating disorders.

Altered skin flowmotion in hypertensive humans

PubMed Central

Bruning, R.S.; Kenney, W.L.; Alexander, L.M.

2017-01-01

Essential hypertensive humans exhibit attenuated cutaneous nitric oxide (NO)-dependent vasodilation. Using spectral analysis (fast Fourier transformation) we aimed to characterize the skin flowmotion contained in the laser-Doppler flowmetry recordings during local heating-induced vasodilation before and after concurrent pharmacological inhibition of nitric oxide synthase (NOS) in hypertensive and age-matched normotensive men and women. We hypothesized that hypertensive subjects would have lower total power spectral densities (PSD), specifically in the frequency intervals associated with intrinsic endothelial and neurogenic control of the microvasculature. Furthermore, we hypothesized that NOS inhibition would attenuate the endothelial frequency interval. Laser-Doppler flowmetry recordings during local heating experiments from 18 hypertensive (MAP: 108±2mmHg) and 18 normotensive (MAP: 88±2mmHg) men and women were analyzed. Within site NO-dependent vasodilation was assessed by perfusion of a non-specific NOS inhibitor (NG-nitro-L-arginine methyl ester; L-NAME) through intradermal microdialysis during the heating-induced plateau in skin blood flow. Local heating-induced vasodilation increased total PSD for all frequency intervals (all p<0.001). Hypertensives had a lower total PSD (p=0.03) and absolute neurogenic frequency intervals (p<0.01) compared to the normotensives. When normalized as a percentage of total PSD, hypertensives had reduced neurogenic (p<0.001) and augmented myogenic contributions (p=0.04) to the total spectrum. NOS inhibition decreased total PSD (p<0.001) for both groups, but hypertensives exhibited lower absolute endothelial (p<0.01), neurogenic (p<0.05), and total PSD (p<0.001) frequency intervals compared to normotensives. These data suggest that essential hypertension results in altered neurogenic and NOS-dependent control of skin flowmotion and support the use of spectral analysis as a non-invasive technique to study vasoreactivity. PMID:24418051

Efficiency of time-lapse intervals and simple baits for camera surveys of wild pigs

USGS Publications Warehouse

Williams, B.L.; Holtfreter, R.W.; Ditchkoff, S.S.; Grand, J.B.

2011-01-01

Growing concerns surrounding established and expanding populations of wild pigs (Sus scrofa) have created the need for rapid and accurate surveys of these populations. We conducted surveys of a portion of the wild pig population on Fort Benning, Georgia, to determine if a longer time-lapse interval than had been previously used in surveys of wild pigs would generate similar detection results. We concurrently examined whether use of soured corn at camera sites affected the time necessary for pigs to locate a new camera site or the time pigs remained at a site. Our results suggest that a 9-min time-lapse interval generated dependable detection results for pigs and that soured corn neither attracted pigs to a site any quicker than plain, dry, whole-kernel corn, nor held them at a site longer. Maximization of time-lapse interval should decrease data and processing loads, and use of a simple, available bait should decrease cost and effort associated with more complicated baits; combination of these concepts should increase efficiency of wild pig surveys. ?? 2011 The Wildlife Society.

Concurrent schedules: Effects of time- and response-allocation constraints

PubMed Central

Davison, Michael

1991-01-01

Five pigeons were trained on concurrent variable-interval schedules arranged on two keys. In Part 1 of the experiment, the subjects responded under no constraints, and the ratios of reinforcers obtainable were varied over five levels. In Part 2, the conditions of the experiment were changed such that the time spent responding on the left key before a subsequent changeover to the right key determined the minimum time that must be spent responding on the right key before a changeover to the left key could occur. When the left key provided a higher reinforcer rate than the right key, this procedure ensured that the time allocated to the two keys was approximately equal. The data showed that such a time-allocation constraint only marginally constrained response allocation. In Part 3, the numbers of responses emitted on the left key before a changeover to the right key determined the minimum number of responses that had to be emitted on the right key before a changeover to the left key could occur. This response constraint completely constrained time allocation. These data are consistent with the view that response allocation is a fundamental process (and time allocation a derivative process), or that response and time allocation are independently controlled, in concurrent-schedule performance. PMID:16812632

Quitting activity and tobacco brand Switching: findings from the ITC-4 Country Survey

PubMed Central

Cowie, Genevieve A.; Swift, Elena; Partos, Timea; Borland, Ron

2015-01-01

Objective Among Australian smokers, to examine associations between cigarette brand switching, quitting activity and possible causal directions by lagging the relationships in different directions. Methods Current smokers from nine waves (2002 to early 2012) of the ITC-4 Country Survey Australian dataset were surveyed. Measures were brand switching, both brand family and product type (roll-your-own versus factory-made cigarettes) reported in adjacent waves, interest in quitting, recent quit attempts, and one month sustained abstinence. Results Switching at one interval was unrelated to concurrent quit interest. Quit interest predicted switching at the following interval, but the effect disappeared once subsequent quit attempts were controlled for. Recent quit attempts more strongly predicted switching at concurrent (OR 1.34, 95% CI=1.18–1.52, p<0.001) and subsequent intervals (OR 1.31, 95% CI= 1.12–1.53, p=0.001) than switching predicted quit attempts, with greater asymmetry when both types of switching were combined. One month sustained abstinence and switching were unrelated in the same interval; however after controlling for concurrent switching and excluding type switchers, sustained abstinence predicted lower chance of switching at the following interval (OR=0.66, 95% CI=0.47–0.93, p=0.016). Conclusions The asymmetry suggests brand switching does not affect subsequent quitting. Implications Brand switching does not appear to interfere with quitting. PMID:25827182

Quitting activity and tobacco brand switching: findings from the ITC-4 Country Survey.

PubMed

Cowie, Genevieve A; Swift, Elena; Partos, Timea; Borland, Ron

2015-04-01

Among Australian smokers, to examine associations between cigarette brand switching, quitting activity and possible causal directions by lagging the relationships in different directions. Current smokers from nine waves (2002 to early 2012) of the ITC-4 Country Survey Australian dataset were surveyed. Measures were brand switching, both brand family and product type (roll-your-own versus factory-made cigarettes) reported in adjacent waves, interest in quitting, recent quit attempts, and one month sustained abstinence. Switching at one interval was unrelated to concurrent quit interest. Quit interest predicted switching at the following interval, but the effect disappeared once subsequent quit attempts were controlled for. Recent quit attempts more strongly predicted switching at concurrent (OR 1.34, 95%CI=1.18-1.52, p<0.001) and subsequent intervals (OR 1.31, 95%CI=1.12-1.53, p=0.001) than switching predicted quit attempts, with greater asymmetry when both types of switching were combined. One month sustained abstinence and switching were unrelated in the same interval; however, after controlling for concurrent switching and excluding type switchers, sustained abstinence predicted lower chance of switching at the following interval (OR=0.66, 95%CI=0.47-0.93, p=0.016). The asymmetry suggests brand switching does not affect subsequent quitting. Brand switching does not appear to interfere with quitting. © 2015 Public Health Association of Australia.

Tibial tuberosity to trochlear groove distance and its association with patellofemoral osteoarthritis-related structural damage worsening: data from the osteoarthritis initiative.

PubMed

Haj-Mirzaian, Arya; Guermazi, Ali; Hakky, Michael; Sereni, Christopher; Zikria, Bashir; Roemer, Frank W; Tanaka, Miho J; Cosgarea, Andrew J; Demehri, Shadpour

2018-04-30

To determine whether the tibial tuberosity-to-trochlear groove (TT-TG) distance is associated with concurrent patellofemoral joint osteoarthritis (OA)-related structural damage and its worsening on 24-month follow-up magnetic resonance imaging (MRI) in participants in the Osteoarthritis Initiative (OAI). Six hundred subjects (one index knee per participant) were assessed. To evaluate patellofemoral OA-related structural damage, baseline and 24-month semiquantitative MRI Osteoarthritis Knee Score (MOAKS) variables for cartilage defects, bone marrow lesions (BMLs), osteophytes, effusion, and synovitis were extracted from available readings. The TT-TG distance was measured in all subjects using baseline MRIs by two musculoskeletal radiologists. The associations between baseline TT-TG distance and concurrent baseline MOAKS variables and their worsening in follow-up MRI were investigated using regression analysis adjusted for variables associated with tibiofemoral and patellofemoral OA. At baseline, increased TT-TG distance was associated with concurrent lateral patellar and trochlear cartilage damages, BML, osteophytes, and knee joint effusion [cross-sectional evaluations; overall odds ratio 95% confidence interval (OR 95% CI): 1.098 (1.045-1.154), p < 0.001]. In the longitudinal analysis, increased TT-TG distance was significantly related to lateral patellar and trochlear cartilage, BML, and joint effusion worsening (overall OR 95% CI: 1.111 (1.056-1.170), p < 0.001). TT-TG distance was associated with simultaneous lateral patellofemoral OA-related structural damage and its worsening over 24 months. Abnormally lateralized tibial tuberosity may be considered as a risk factor for future patellofemoral OA worsening. • Excessive TT-TG distance on MRI is an indicator/predictor of lateral-patellofemoral-OA. • TT-TG is associated with simultaneous lateral-patellofemoral-OA (6-17% chance-increase for each millimeter increase). • TT-TG is associated with longitudinal (24-months) lateral-patellofemoral-OA (5-15% chance-increase for each millimeter).

Future Interannual Variability of Arctic Sea Ice Area and its Implications for Marine Navigation

NASA Astrophysics Data System (ADS)

Vavrus, S. J.; Mioduszewski, J.; Holland, M. M.; Wang, M.; Landrum, L.

2016-12-01

As both a symbol and driver of ongoing climate change, the diminishing Arctic sea ice pack has been widely studied in a variety of contexts. Most research, however, has focused on time-mean changes in sea ice, rather than on short-term variations that also have important physical and societal consequences. In this study we test the hypothesis that interannual Arctic sea ice variability will increase in the future by utilizing a set of 40 independent simulations from the Community Earth System Model's Large Ensemble for the 1920-2100 period. The model projects that ice variability will indeed grow substantially in all months but with a strong seasonal dependence in magnitude and timing. The variability increases most during late autumn (November-December) and least during spring. This increase proceeds in a time-transgressive manner over the course of the year, peaking soonest (2020s) in late-summer months and latest (2090s) during late spring. The variability in every month is inversely correlated with the average melt rate, resulting in an eventual decline in both terms as the ice pack becomes seasonal by late century. These projected changes in sea ice variations will likely have significant consequences for marine navigation, which we assess with the empirical Ice Numeral (IN) metric. A function of ice concentration and thickness, the IN quantifies the difficulty in traversing a transect of sea ice-covered ocean as a function of vessel strength. Our results show that although increasingly open Arctic seas will mean generally more favorable conditions for navigation, the concurrent rise in the variability of ice cover poses a competing risk. In particular, future intervals featuring the most rapid declines in ice area that coincide with the highest interannual ice variations will offer more inviting shipping opportunities tempered by less predictable navigational conditions.

Concurrency and HIV transmission network characteristics among MSM with recent HIV infection.

PubMed

Pines, Heather A; Wertheim, Joel O; Liu, Lin; Garfein, Richard S; Little, Susan J; Karris, Maile Y

2016-11-28

Sexual partner concurrency is common among MSM and may increase the probability of HIV transmission during recent (acute or early) infection. We examined the relationship between concurrency and HIV transmission network characteristics (proxies for HIV transmission) among MSM with recent HIV infection. Observational study integrating behavioral, clinical, and molecular epidemiology. We inferred a partial HIV transmission network using 986 HIV-1 pol sequences obtained from HIV-infected individuals in San Diego, California (1996-2015). We further analyzed data from 285 recently HIV-infected MSM in the network who provided information on up to three sexual partners in the past 3 months, including the timing of intercourse with each partner. Concurrency was defined as sexual partners overlapping in time. Logistic and negative binomial regressions were used to investigate the link between concurrency and HIV transmission network characteristics (i.e. clustering and degree or number of connections to others in the network) among these MSM. Of recently HIV-infected MSM (n = 285), 54% reported concurrent partnerships and 54% were connected by at least one putative transmission link to others (i.e. clustered) in the network (median degree = 1.0; interquartile range: 0.0-3.0). Concurrency was positively associated with HIV transmission network clustering (adjusted odds ratio = 1.83, 95% confidence interval: 1.08, 3.10) and degree (adjusted incidence rate ratio = 1.48, 95% confidence interval: 1.02, 2.15). Our findings provide empirical evidence consistent with the hypothesis that concurrency facilitates HIV transmission during recent infection. Interventions to mitigate the impact of concurrency on HIV transmission may help curb the HIV epidemic among MSM.

Impact of high-intensity concurrent training on cardiovascular risk factors in persons with multiple sclerosis - pilot study.

PubMed

Keytsman, Charly; Hansen, Dominique; Wens, Inez; O Eijnde, Bert

2017-10-27

High-intensity concurrent training positively affects cardiovascular risk factors. Because this was never investigated in multiple sclerosis, the present pilot study explored the impact of this training on cardiovascular risk factors in this population. Before and after 12 weeks of high-intense concurrent training (interval and strength training, 5 sessions per 2 weeks, n = 16) body composition, resting blood pressure and heart rate, 2-h oral glucose tolerance (insulin sensitivity, glycosylated hemoglobin, blood glucose and insulin concentrations), blood lipids (high- and low-density lipoprotein, total cholesterol, triglyceride levels) and C-reactive protein were analyzed. Twelve weeks of high-intense concurrent training significantly improved resting heart rate (-6%), 2-h blood glucose concentrations (-13%) and insulin sensitivity (-24%). Blood pressure, body composition, blood lipids and C-reactive protein did not seem to be affected. Under the conditions of this pilot study, 12 weeks of concurrent high-intense interval and strength training improved resting heart rate, 2-h glucose and insulin sensitivity in multiple sclerosis but did not affect blood C-reactive protein levels, blood pressure, body composition and blood lipid profiles. Further, larger and controlled research investigating the effects of high-intense concurrent training on cardiovascular risk factors in multiple sclerosis is warranted. Implications for rehabilitation High-intensity concurrent training improves cardiovascular fitness. This pilot study explores the impact of this training on cardiovascular risk factors in multiple sclerosis. Despite the lack of a control group, high-intense concurrent training does not seem to improve cardiovascular risk factors in multiple sclerosis.

On the Spike Train Variability Characterized by Variance-to-Mean Power Relationship.

PubMed

Koyama, Shinsuke

2015-07-01

We propose a statistical method for modeling the non-Poisson variability of spike trains observed in a wide range of brain regions. Central to our approach is the assumption that the variance and the mean of interspike intervals are related by a power function characterized by two parameters: the scale factor and exponent. It is shown that this single assumption allows the variability of spike trains to have an arbitrary scale and various dependencies on the firing rate in the spike count statistics, as well as in the interval statistics, depending on the two parameters of the power function. We also propose a statistical model for spike trains that exhibits the variance-to-mean power relationship. Based on this, a maximum likelihood method is developed for inferring the parameters from rate-modulated spike trains. The proposed method is illustrated on simulated and experimental spike trains.

Impact of Rehabilitation on Outcomes in Patients With Ischemic Stroke: A Nationwide Retrospective Cohort Study in Japan.

PubMed

Yagi, Maiko; Yasunaga, Hideo; Matsui, Hiroki; Morita, Kojiro; Fushimi, Kiyohide; Fujimoto, Masashi; Koyama, Teruyuki; Fujitani, Junko

2017-03-01

We aimed to examine the concurrent effects of timing and intensity of rehabilitation on improving activities of daily living (ADL) among patients with ischemic stroke. Using the Japanese Diagnosis Procedure Combination inpatient database, we retrospectively analyzed consecutive patients with ischemic stroke at admission who received rehabilitation (n=100 719) from April 2012 to March 2014. Early rehabilitation was defined as that starting within 3 days after admission. The average rehabilitation intensity per day was calculated as the total units of rehabilitation during hospitalization divided by the length of hospital stay. A multivariable logistic regression analysis with multiple imputation and an instrumental variable analysis were performed to examine the association of early and intensive rehabilitation with the proportion of improved ADL score. The proportion of improved ADL score was higher in the early and intensive rehabilitation group. The multivariable logistic regression analysis showed that significant improvements in ADL were observed for early rehabilitation (odds ratio: 1.08; 95% confidence interval: 1.04-1.13; P <0.01) and intensive rehabilitation of >5.0 U/d (odds ratio: 1.87; 95% confidence interval: 1.69-2.07; P <0.01). The instrumental variable analysis showed that an increased proportion of improved ADL was associated with early rehabilitation (risk difference: 2.8%; 95% confidence interval: 2.0-3.4%; P <0.001) and intensive rehabilitation (risk difference: 5.6%; 95% confidence interval: 4.6-6.6%; P <0.001). The present results suggested that early and intensive rehabilitation improved ADL during hospitalization in patients with ischemic stroke. © 2017 American Heart Association, Inc.

Interaction of attentional and motor control processes in handwriting.

PubMed

Brown, T L; Donnenwirth, E E

1990-01-01

The interaction between attentional capacity, motor control processes, and strategic adaptations to changing task demands was investigated in handwriting, a continuous (rather than discrete) skilled performance. Twenty-four subjects completed 12 two-minute handwriting samples under instructions stressing speeded handwriting, normal handwriting, or highly legible handwriting. For half of the writing samples, a concurrent auditory monitoring task was imposed. Subjects copied either familiar (English) or unfamiliar (Latin) passages. Writing speed, legibility ratings, errors in writing and in the secondary auditory task, and a derived measure of the average number of characters held in short-term memory during each sample ("planning unit size") were the dependent variables. The results indicated that the ability to adapt to instructions stressing speed or legibility was substantially constrained by the concurrent listening task and by text familiarity. Interactions between instructions, task concurrence, and text familiarity in the legibility ratings, combined with further analyses of planning unit size, indicated that information throughput from temporary storage mechanisms to motor processes mediated the loss of flexibility effect. Overall, the results suggest that strategic adaptations of a skilled performance to changing task circumstances are sensitive to concurrent attentional demands and that departures from "normal" or "modal" performance require attention.

Effects of Sarin on the Operant Behavior of Guinea Pigs

DTIC Science & Technology

2005-07-19

a after behavioral sessions had ended. The first collection time modified autoshaping procedure (concurrent variable-time was after the final saline...after behavioral sessions had ended. The first collection time modified autoshaping procedure (concurrent variable-time was after the final saline

Human choice among five alternatives when reinforcers decay.

PubMed

Rothstein, Jacob B; Jensen, Greg; Neuringer, Allen

2008-06-01

Human participants played a computer game in which choices among five alternatives were concurrently reinforced according to dependent random-ratio schedules. "Dependent" indicates that choices to any of the wedges activated the random-number generators governing reinforcers on all five alternatives. Two conditions were compared. In the hold condition, once scheduled, a reinforcer - worth a constant five points - remained available until it was collected. In the decay condition, point values decreased with intervening responses, i.e., rapid collection was differentially reinforced. Slopes of matching functions were higher in the decay than hold condition. However inter-subject variability was high in both conditions.

Assessment of the Tobacco Dependence Screener Among Smokeless Tobacco Users.

PubMed

Mushtaq, Nasir; Beebe, Laura A

2016-05-01

Variants of the Fagerström Tolerance Questionnaire and Fagerström Test for Nicotine Dependence (FTND) are widely used to study dependence among smokeless tobacco (ST) users. However, there is a need for a dependence measure which is based on the clinical definition of dependence and is easy to administer. The Tobacco Dependence Screener (TDS), a self-administered 10-item scale, is based on the Diagnostic and Statistical Manual, fourth edition (DSM-IV) and ICD-10 definitions of dependence. It is commonly used as a tobacco dependence screening tool in cigarette smoking studies but it has not been evaluated for dependence in ST users. The purpose of this study is to evaluate the TDS as a measure of tobacco dependence among ST users. Data collected from a community-based sample of exclusive ST users living in Oklahoma (n = 95) was used for this study. TDS was adapted to be used for ST dependence as the references for smoking were changed to ST use. Concurrent validity and reliability of TDS were evaluated. Salivary cotinine concentration was used as a criterion variable. Overall accuracy of the TDS was assessed by receiver's operating characteristic (ROC) curve and optimal cutoff scores for dependence diagnosis were evaluated. There was no floor or ceiling effect in TDS score (mean = 5.42, SD = 2.61). Concurrent validity of TDS as evaluated by comparing it with FTND-ST was affirmative. Study findings showed significant association between TDS and salivary cotinine concentration. The internal consistency assessed by Cronbach's alpha indicated that TDS had acceptable reliability (α = 0.765). TDS was negatively correlated with time to first chew/dip and positively correlated with frequency (number of chews per day) and years of ST use. Results of logistic regression analysis showed that at an optimal cutoff score of TDS 5+, ST users classified as dependent had significantly higher cotinine concentration and FTND-ST scores. TDS demonstrated acceptable reliability and concurrent validity among ST users. These findings are consistent with the results of previous cigarette smoking studies evaluating TDS. A self-administered tobacco dependence measure for ST users based on a clinical definition of dependence is an effective tool in research setting. ST dependence research is still evolving. This is the first study of the TDS among ST users providing preliminary evidence about some of the psychometric properties of the scale. Similar to cigarette smokers, TDS is an effective measure of ST dependence. Study showed moderate reliability and affirmative concurrent validity of the TDS among ST users. © The Author 2015. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Experiences of victimisation and depression are associated with community functioning among men with schizophrenia.

PubMed

Hodgins, Sheilagh; Lincoln, Tania; Mak, Tim

2009-06-01

The present study aimed to identify proximal and distal factors associated with real life community functioning among men with schizophrenia. Real life community functioning was defined to include: independent living, occupational functioning, social and leisure activities, and substance misuse, self-harm, and aggressive behaviour. 225 men with schizophrenia or schizo-affective disorder were assessed at discharge from hospital and at six-monthly intervals during a two-year period. Information was available from structured interviews with the participants, family members and treatment staff, records of psychiatric treatment, social service files, and official criminal records. Symptoms were assessed using the Positive and Negative Symptom Scale and the Hamilton Rating Scale for Depression. Substance misuse was measured by self-report and hair and urine analyses. Predictors of outcome were divided into four categories: childhood, adulthood, year prior to functional outcome assessment, and con-current. In a final regression model, five predictors were significantly associated with patients' real life functioning: two adult life-time variables-a diagnosis of drug abuse/dependence and level of education and three current variables-victimisation, depression, and medication non-compliance. Most of the variance in the final outcome scores was explained by current predictors. In order to elevate levels of psychosocial functioning among men with schizophrenia, clinicians need to assess victimisation experiences, and, when present, design and implement interventions to help patients protect themselves. In addition, depression needs to be identified and treated, and compliance with antipsychotic medication assured.

Statistical analysis and use of the VAS radiance data

NASA Technical Reports Server (NTRS)

Fuelberg, H. E.

1984-01-01

Special radiosonde soundings at 75 km spacings and 3 hour intervals provided an opportunity to learn more about mesoscale data and storm-environment interactions. Relatively small areas of intense convection produce major changes in surrounding fields of thermodynamic, kinematic, and energy variables. The Red River Valley tornado outbreak was studied. Satellite imagery and surface data were used to specify cloud information needed in the radiative heating/cooling calculations. A feasibility study for computing boundary layer winds from satellite-derived thermal data was completed. Winds obtained from TIROS-N retrievals compared very favorably with corresponding values from concurrent rawisonde thermal data, and both sets of thermally-derived winds showed good agreements with observed values.

Evaluation of the satellite derived snow cover area - Runoff forecasting models for the inaccessible basins of western Himalayas

NASA Technical Reports Server (NTRS)

Dey, B.

1985-01-01

In this study, the existing seasonal snow cover area runoff forecasting models of the Indus, Kabul, Sutlej and Chenab basins were evaluated with the concurrent flow correlation model for the period 1975-79. In all the basins under study, correlation of concurrent flow model explained the variability in flow better than by the snow cover area runoff models. Actually, the concurrent flow correlation model explained more than 90 percent of the variability in the flow of these rivers. Compared to this model, the snow cover area runoff models explained less of the variability in flow. In the Himalayan river basins under study and at least for the period under observation, the concurrent flow correlation model provided a set of results with which to compare the estimates from the snow cover area runoff models.

Concurrent validity of the Swedish version of the life-space assessment questionnaire.

PubMed

Fristedt, Sofi; Kammerlind, Ann-Sofi; Bravell, Marie Ernsth; Fransson, Eleonor I

2016-11-08

The Life-Space Assessment (LSA), developed in the USA, is an instrument focusing on mobility with respect to reaching different areas defined as life-spaces, extending from the room where the person sleeps to mobility outside one's hometown. A newly translated Swedish version of the LSA (LSA-S) has been tested for test-retest reliability, but the validity remains to be tested. The purpose of the present study was to examine the concurrent validity of the LSA-S, by comparing and correlating the LSA scores to other measures of mobility. The LSA was included in a population-based study of health, functioning and mobility among older persons in Sweden, and the present analysis comprised 312 community-dwelling participants. To test the concurrent validity, the LSA scores were compared to a number of other mobility-related variables, including the Short Physical Performance Battery (SPPB) as well as "stair climbing", "transfers", "transportation", "food shopping", "travel for pleasure" and "community activities". The LSA total mean scores for different levels of the other mobility-related variables, and measures of correlation were calculated. Higher LSA total mean scores were observed with higher levels of all the other mobility related variables. Most of the correlations between the LSA and the other mobility variables were large (r = 0.5-1.0) and significant at the 0.01 level. The LSA total score, as well as independent life-space and assistive life-space correlated with transportation (0.63, 0.66, 0.64) and food shopping (0.55, 0.58, 0.55). Assistive life-space also correlated with SPPB (0.47). With respect to maximal life-space, the correlations with the mobility-related variables were generally lower (below 0.5), probably since this aspect of life-space mobility is highly influenced by social support and is not so dependent on the individual's own physical function. LSA was shown to be a valid measure of mobility when using the LSA total, independent LS or assistive LSA.

Speech variability effects on recognition accuracy associated with concurrent task performance by pilots

NASA Technical Reports Server (NTRS)

Simpson, C. A.

1985-01-01

In the present study of the responses of pairs of pilots to aircraft warning classification tasks using an isolated word, speaker-dependent speech recognition system, the induced stress was manipulated by means of different scoring procedures for the classification task and by the inclusion of a competitive manual control task. Both speech patterns and recognition accuracy were analyzed, and recognition errors were recorded by type for an isolated word speaker-dependent system and by an offline technique for a connected word speaker-dependent system. While errors increased with task loading for the isolated word system, there was no such effect for task loading in the case of the connected word system.

Exponential synchronization of neural networks with discrete and distributed delays under time-varying sampling.

PubMed

Wu, Zheng-Guang; Shi, Peng; Su, Hongye; Chu, Jian

2012-09-01

This paper investigates the problem of master-slave synchronization for neural networks with discrete and distributed delays under variable sampling with a known upper bound on the sampling intervals. An improved method is proposed, which captures the characteristic of sampled-data systems. Some delay-dependent criteria are derived to ensure the exponential stability of the error systems, and thus the master systems synchronize with the slave systems. The desired sampled-data controller can be achieved by solving a set of linear matrix inequalitys, which depend upon the maximum sampling interval and the decay rate. The obtained conditions not only have less conservatism but also have less decision variables than existing results. Simulation results are given to show the effectiveness and benefits of the proposed methods.

Prohibiting consent: what are the costs of denying permanent contraception concurrent with abortion care?

PubMed

Krashin, Jamie W; Edelman, Alison B; Nichols, Mark D; Allen, Allison J; Caughey, Aaron B; Rodriguez, Maria I

2014-07-01

Oregon and federal laws prohibit giving informed consent for permanent contraception when presenting for an abortion. The primary objective of this study was to estimate the number of unintended pregnancies associated with this barrier to obtaining concurrent tubal occlusion and abortion, compared with the current policy, which limits women to obtaining interval tubal occlusion after abortion. The secondary objectives were to compare the financial costs, quality-adjusted life years, and the cost-effectiveness of these policies. We designed a decision-analytic model examining a theoretical population of women who requested tubal occlusion at time of abortion. Model inputs came from the literature. We examined the primary and secondary outcomes stratified by maternal age (>30 and <30 years). A Markov model incorporated the possibility of multiple pregnancies. Sensitivity analyses were performed on all variables and a Monte Carlo simulation was conducted. For every 1000 women age <30 years in Oregon who did not receive requested tubal occlusion at the time of abortion, over 5 years there would be 1274 additional unintended pregnancies and an additional $4,152,373 in direct medical costs. Allowing women to receive tubal occlusion at time of abortion was the dominant strategy. It resulted in both lower costs and greater quality-adjusted life years compared to allowing only interval tubal occlusion after abortion. Prohibiting tubal occlusion at time of abortion resulted in an increased incidence of unintended pregnancy and increased public costs. Copyright © 2014 Mosby, Inc. All rights reserved.

Spectral variability of sea surface skylight reflectance and its effect on ocean color.

PubMed

Cui, Ting-Wei; Song, Qing-Jun; Tang, Jun-Wu; Zhang, Jie

2013-10-21

In this study, sea surface skylight spectral reflectance ρ(λ) was retrieved by means of the non-linear spectral optimization method and a bio-optical model. The spectral variability of ρ(λ) was found to be mainly influenced by the uniformity of the incident skylight, and a model is proposed to predict the ρ(λ) spectral dependency based on skylight reflectance at 750 nm. It is demonstrated that using the spectrally variable ρ(λ), rather than a constant, yields an improved agreement between the above-water remote sensing reflectance R(rs)(λ) estimates and concurrent profiling ones. The findings of this study highlight the necessity to re-process the relevant historical above-water data and update ocean color retrieval algorithms accordingly.

An efficient sampling approach for variance-based sensitivity analysis based on the law of total variance in the successive intervals without overlapping

NASA Astrophysics Data System (ADS)

Yun, Wanying; Lu, Zhenzhou; Jiang, Xian

2018-06-01

To efficiently execute the variance-based global sensitivity analysis, the law of total variance in the successive intervals without overlapping is proved at first, on which an efficient space-partition sampling-based approach is subsequently proposed in this paper. Through partitioning the sample points of output into different subsets according to different inputs, the proposed approach can efficiently evaluate all the main effects concurrently by one group of sample points. In addition, there is no need for optimizing the partition scheme in the proposed approach. The maximum length of subintervals is decreased by increasing the number of sample points of model input variables in the proposed approach, which guarantees the convergence condition of the space-partition approach well. Furthermore, a new interpretation on the thought of partition is illuminated from the perspective of the variance ratio function. Finally, three test examples and one engineering application are employed to demonstrate the accuracy, efficiency and robustness of the proposed approach.

Distorted Beliefs about Luck and Skill and Their Relation to Gambling Problems and Gambling Behavior in Dutch Gamblers.

PubMed

Cowie, Megan E; Stewart, Sherry H; Salmon, Joshua; Collins, Pam; Al-Hamdani, Mohammed; Boffo, Marilisa; Salemink, Elske; de Jong, David; Smits, Ruby; Wiers, Reinout W

2017-01-01

Gamblers' cognitive distortions are thought to be an important mechanism involved in the development and maintenance of problem gambling. The Gambling Cognitions Inventory (GCI) evaluates two categories of distortions: beliefs that one is lucky (i.e., "Luck/Chance") and beliefs that one has special gambling-related skills (i.e., "Skill/Attitude"). Prior psychometric evaluations of the GCI demonstrated the utility of both subscales as measures of distortions and their concurrent relations to gambling problems among Canadian gamblers. However, these associations have not yet been studied in gamblers from other cultures nor have relationships between the GCI and indices of gambling behavior been investigated. In addition, the predictive validity of the GCI scales have not been evaluated in studies to date. The present study investigated the validity of the GCI as a measure of cognitive distortions in a sample of 49 Dutch gamblers by examining its concurrent and prospective relationships to both gambling problems (as measured through a standardized nine-item questionnaire assessing gambling-related problems) and behaviors (as measured through two variables: days spent gambling and time spent gambling in minutes) at baseline and over 1-month and 6-month intervals. The GCI subscales were internally consistent at all timepoints, and moderately to strongly inter-correlated at all timepoints. Each subscale correlated with an independent dimension of gambling both concurrently and prospectively: Luck/Chance was related to greater gambling problems and Skill/Attitude was related to greater gambling behavior . Thus, the two GCI subscales, while inter-correlated, appear to be related to different gambling outcomes, at least among Dutch gamblers. Moreover, the first evidence of the predictive validity of the GCI scales was demonstrated over a 1-month and 6-month interval. It is recommended that both types of cognitive distortions be considered in research and clinical practice to fully understand and address individual risk for excessive and problematic gambling.

Distorted Beliefs about Luck and Skill and Their Relation to Gambling Problems and Gambling Behavior in Dutch Gamblers

PubMed Central

Cowie, Megan E.; Stewart, Sherry H.; Salmon, Joshua; Collins, Pam; Al-Hamdani, Mohammed; Boffo, Marilisa; Salemink, Elske; de Jong, David; Smits, Ruby; Wiers, Reinout W.

2017-01-01

Gamblers’ cognitive distortions are thought to be an important mechanism involved in the development and maintenance of problem gambling. The Gambling Cognitions Inventory (GCI) evaluates two categories of distortions: beliefs that one is lucky (i.e., “Luck/Chance”) and beliefs that one has special gambling-related skills (i.e., “Skill/Attitude”). Prior psychometric evaluations of the GCI demonstrated the utility of both subscales as measures of distortions and their concurrent relations to gambling problems among Canadian gamblers. However, these associations have not yet been studied in gamblers from other cultures nor have relationships between the GCI and indices of gambling behavior been investigated. In addition, the predictive validity of the GCI scales have not been evaluated in studies to date. The present study investigated the validity of the GCI as a measure of cognitive distortions in a sample of 49 Dutch gamblers by examining its concurrent and prospective relationships to both gambling problems (as measured through a standardized nine-item questionnaire assessing gambling-related problems) and behaviors (as measured through two variables: days spent gambling and time spent gambling in minutes) at baseline and over 1-month and 6-month intervals. The GCI subscales were internally consistent at all timepoints, and moderately to strongly inter-correlated at all timepoints. Each subscale correlated with an independent dimension of gambling both concurrently and prospectively: Luck/Chance was related to greater gambling problems and Skill/Attitude was related to greater gambling behavior. Thus, the two GCI subscales, while inter-correlated, appear to be related to different gambling outcomes, at least among Dutch gamblers. Moreover, the first evidence of the predictive validity of the GCI scales was demonstrated over a 1-month and 6-month interval. It is recommended that both types of cognitive distortions be considered in research and clinical practice to fully understand and address individual risk for excessive and problematic gambling. PMID:29312086

Rapid Acquisition in Concurrent Chains: Evidence for a Decision Model

ERIC Educational Resources Information Center

Grace, Randolph C.; McLean, Anthony P.

2006-01-01

Pigeons' choice in concurrent chains can adapt to rapidly changing contingencies. Grace, Bragason, and McLean (2003) found that relative initial-link response rate was sensitive to the immediacy ratio in the current session when one of the terminal-link fixed-interval schedules was changed daily according to a pseudorandom binary sequence (e.g.,…

Patterns of Care for Elderly Patients With Locally Advanced Head and Neck Cancer.

PubMed

Juarez, Jesus E; Choi, Jehee; St John, Maie; Abemayor, Elliot; TenNapel, Mindi; Chen, Allen M

2017-07-15

To compare patterns of care for elderly patients aged ≥70 years with locally advanced head and neck cancer versus those of younger patients treated for the same disease. The medical records of 421 consecutive patients over the age of 50 years treated at a single institution between April 2011 and June 2016 for stage III/IV squamous cell carcinoma of the head and neck were reviewed. The primary treatment approach was compared using a t test statistic among 3 age cohorts: 50 to 59 years (118 patients); 60 to 69 years (152 patients); and 70 years and older (151 patients). Logistical regression was used to determine variables that influenced the likelihood of receiving surgery versus nonsurgical treatment, as well as radiation alone versus chemoradiation. There was no difference in sex, T stage, N stage, Karnofsky performance status, or the number of chronic comorbid conditions among the 3 age cohorts (P>.05 for all). A greater proportion of elderly patients aged ≥70 years were treated by radiation alone compared with those aged 50 to 59 and 60 to 69 years (44% vs 16% and 24%, P=.01). Increasing age was associated with a greater likelihood of receiving primary nonsurgical versus surgical treatment (odds ratio 1.023, 95% confidence interval 1.004-1.042) and radiation alone compared with chemoradiation (odds ratio 1.054; 95% confidence interval 1.034-1.075). Ten chemotherapy regimens were used concurrently with radiation for patients aged ≥70 years, including carboplatin/paclitaxel (19%), carboplatin/cetuximab (19%), cisplatin (17%), and cetuximab (17%). Despite similar performance status and comorbidity burden compared with their younger counterparts, patients aged ≥70 years were more commonly treated with less-aggressive strategies, including radiation alone. The variability of concurrent chemotherapy regimens used further suggests that the standard of care remains to be defined for this population. Copyright © 2017 Elsevier Inc. All rights reserved.

Anesthesia information management system-based near real-time decision support to manage intraoperative hypotension and hypertension.

PubMed

Nair, Bala G; Horibe, Mayumi; Newman, Shu-Fang; Wu, Wei-Ying; Peterson, Gene N; Schwid, Howard A

2014-01-01

Intraoperative hypotension and hypertension are associated with adverse clinical outcomes and morbidity. Clinical decision support mediated through an anesthesia information management system (AIMS) has been shown to improve quality of care. We hypothesized that an AIMS-based clinical decision support system could be used to improve management of intraoperative hypotension and hypertension. A near real-time AIMS-based decision support module, Smart Anesthesia Manager (SAM), was used to detect selected scenarios contributing to hypotension and hypertension. Specifically, hypotension (systolic blood pressure <80 mm Hg) with a concurrent high concentration (>1.25 minimum alveolar concentration [MAC]) of inhaled drug and hypertension (systolic blood pressure >160 mm Hg) with concurrent phenylephrine infusion were detected, and anesthesia providers were notified via "pop-up" computer screen messages. AIMS data were retrospectively analyzed to evaluate the effect of SAM notification messages on hypotensive and hypertensive episodes. For anesthetic cases 12 months before (N = 16913) and after (N = 17132) institution of SAM messages, the median duration of hypotensive episodes with concurrent high MAC decreased with notifications (Mann Whitney rank sum test, P = 0.031). However, the reduction in the median duration of hypertensive episodes with concurrent phenylephrine infusion was not significant (P = 0.47). The frequency of prolonged episodes that lasted >6 minutes (sampling period of SAM), represented in terms of the number of cases with episodes per 100 surgical cases (or percentage occurrence), declined with notifications for both hypotension with >1.25 MAC inhaled drug episodes (δ = -0.26% [confidence interval, -0.38% to -0.11%], P < 0.001) and hypertension with phenylephrine infusion episodes (δ = -0.92% [confidence interval, -1.79% to -0.04%], P = 0.035). For hypotensive events, the anesthesia providers reduced the inhaled drug concentrations to <1.25 MAC 81% of the time with notifications compared with 59% without notifications (P = 0.003). For hypertensive episodes, although the anesthesia providers' reduction or discontinuation of the phenylephrine infusion increased from 22% to 37% (P = 0.030) with notification messages, the overall response was less consistent than the response to hypotensive episodes. With automatic acquisition of arterial blood pressure and inhaled drug concentration variables in an AIMS, near real-time notification was effective in reducing the duration and frequency of hypotension with concurrent >1.25 MAC inhaled drug episodes. However, since phenylephrine infusion is manually documented in an AIMS, the impact of notification messages was less pronounced in reducing episodes of hypertension with concurrent phenylephrine infusion. Automated data capture and a higher frequency of data acquisition in an AIMS can improve the effectiveness of an intraoperative clinical decision support system.

Stock optimizing in choice when a token deposit is the operant.

PubMed

Widholm, J J; Silberberg, A; Hursh, S R; Imam, A A; Warren-Boulton, F R

2001-11-01

Each of 2 monkeys typically earned their daily food ration by depositing tokens in one of two slots. Tokens deposited in one slot dropped into a bin where they were kept (token kept). Deposits to a second slot dropped into a bin where they could be obtained again (token returned). In Experiment 1, a fixed-ratio (FR) 5 schedule that provided two food pellets was associated with each slot. Both monkeys preferred the token-returned slot. In Experiment 2, both subjects chose between unequal FR schedules with the token-returned slot always associated with the leaner schedule. When the FRs were 2 versus 3 and 2 versus 6, preferences were maintained for the token-returned slot; however, when the ratios were 2 versus 12, preference shifted to the token-kept slot. In Experiment 3, both monkeys chose between equal-valued concurrent variable-interval variable-interval schedules. Both monkeys preferred the slot that returned tokens. In Experiment 4, both monkeys chose between FRs that typically differed in size by a factor of 10. Both monkeys preferred the FR schedule that provided more food per trial. These data show that monkeys will choose so as to increase the number of reinforcers earned (stock optimizing) even when this preference reduces the rate of reinforcement (all reinforcers divided by session time).

Efficiently sampling conformations and pathways using the concurrent adaptive sampling (CAS) algorithm

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahn, Surl-Hee; Grate, Jay W.; Darve, Eric F.

Molecular dynamics (MD) simulations are useful in obtaining thermodynamic and kinetic properties of bio-molecules but are limited by the timescale barrier, i.e., we may be unable to efficiently obtain properties because we need to run microseconds or longer simulations using femtoseconds time steps. While there are several existing methods to overcome this timescale barrier and efficiently sample thermodynamic and/or kinetic properties, problems remain in regard to being able to sample un- known systems, deal with high-dimensional space of collective variables, and focus the computational effort on slow timescales. Hence, a new sampling method, called the “Concurrent Adaptive Sampling (CAS) algorithm,”more » has been developed to tackle these three issues and efficiently obtain conformations and pathways. The method is not constrained to use only one or two collective variables, unlike most reaction coordinate-dependent methods. Instead, it can use a large number of collective vari- ables and uses macrostates (a partition of the collective variable space) to enhance the sampling. The exploration is done by running a large number of short simula- tions, and a clustering technique is used to accelerate the sampling. In this paper, we introduce the new methodology and show results from two-dimensional models and bio-molecules, such as penta-alanine and triazine polymer« less

It is complicated: sexual partner characteristic profiles and sexually transmitted infection rates within a predominantly African American population in Mississippi.

PubMed

Alexander, Jalen; Rose, Jennifer; Dierker, Lisa; Chan, Philip A; MacCarthy, Sarah; Simmons, Dantrell; Mena, Leandro; Nunn, Amy

2015-05-01

Mississippi has among the highest prevalence of sexually transmitted infections (STIs) in the United States. Understanding sexual networks can provide insight into risk factors for transmission and guide prevention interventions. Participants included 1437 primarily African American (95%) adults presenting for care at an STI clinic in Jackson, Mississippi. Latent class analysis identified underlying population subgroups with unique patterns of response on a comprehensive set of 14 sexual partner variables, such as living with or having a child with a partner, partner dependence and trust, 1-time sexual encounters, multiple main partners, substance use, sexual concurrency, and incarceration. Classes were compared on participant age, sex, sexual orientation, public assistance, lifetime partners, relationship status, and self-reported past-year STI. Three classes emerged. Class 1 (n = 746) participants were less dependent on partners and less likely to live with or have a child with a partner. Class 2 participants (n = 427) endorsed multiple STI risk factors, including partner incarceration, 6 or more lifetime partners, sexual concurrency, 1-time sexual encounters, and substance use at last sex. Class 3 participants (n = 226) were more likely to be in dependent, committed relationships with children. Class 2 had a higher proportion of self-report past-year STIs (36.7%) compared with classes 1 (26.6%) and 3 (26.1%). Certain partner factors such as incarceration, substance use, and concurrency may contribute to increased STI risk. Partner factors may be useful proxies for STI risks and could be useful questions to include in screening questionnaires in clinical settings.

Examination of two methods for statistical analysis of data with magnitude and direction emphasizing vestibular research applications

NASA Technical Reports Server (NTRS)

Calkins, D. S.

1998-01-01

When the dependent (or response) variable response variable in an experiment has direction and magnitude, one approach that has been used for statistical analysis involves splitting magnitude and direction and applying univariate statistical techniques to the components. However, such treatment of quantities with direction and magnitude is not justifiable mathematically and can lead to incorrect conclusions about relationships among variables and, as a result, to flawed interpretations. This note discusses a problem with that practice and recommends mathematically correct procedures to be used with dependent variables that have direction and magnitude for 1) computation of mean values, 2) statistical contrasts of and confidence intervals for means, and 3) correlation methods.

The Developmental Effect of Concurrent Cognitive and Locomotor Skills: Time-Sharing from a Dynamical Perspective.

ERIC Educational Resources Information Center

Whitall, Jill

1991-01-01

Presents research on the effects of concurrent verbal cognition on locomotor skills. Results revealed no interference with coordination variables across age, but some interference with control variables, particularly in younger subjects. Coordination of gait required less attention than setting of control parameters. This coordination was in place…

What Is the Shape of Developmental Change?

PubMed Central

Adolph, Karen E.; Robinson, Scott R.; Young, Jesse W.; Gill-Alvarez, Felix

2009-01-01

Developmental trajectories provide the empirical foundation for theories about change processes during development. However, the ability to distinguish among alternative trajectories depends on how frequently observations are sampled. This study used real behavioral data, with real patterns of variability, to examine the effects of sampling at different intervals on characterization of the underlying trajectory. Data were derived from a set of 32 infant motor skills indexed daily during the first 18 months. Larger sampling intervals (2-31 days) were simulated by systematically removing observations from the daily data and interpolating over the gaps. Infrequent sampling caused decreasing sensitivity to fluctuations in the daily data: Variable trajectories erroneously appeared as step-functions and estimates of onset ages were increasingly off target. Sensitivity to variation decreased as an inverse power function of sampling interval, resulting in severe degradation of the trajectory with intervals longer than 7 days. These findings suggest that sampling rates typically used by developmental researchers may be inadequate to accurately depict patterns of variability and the shape of developmental change. Inadequate sampling regimes therefore may seriously compromise theories of development. PMID:18729590

Aircraft Configuration and Flight Crew Compliance with Procedures While Conducting Flight Deck Based Interval Management (FIM) Operations

NASA Technical Reports Server (NTRS)

Shay, Rick; Swieringa, Kurt A.; Baxley, Brian T.

2012-01-01

Flight deck based Interval Management (FIM) applications using ADS-B are being developed to improve both the safety and capacity of the National Airspace System (NAS). FIM is expected to improve the safety and efficiency of the NAS by giving pilots the technology and procedures to precisely achieve an interval behind the preceding aircraft by a specific point. Concurrently but independently, Optimized Profile Descents (OPD) are being developed to help reduce fuel consumption and noise, however, the range of speeds available when flying an OPD results in a decrease in the delivery precision of aircraft to the runway. This requires the addition of a spacing buffer between aircraft, reducing system throughput. FIM addresses this problem by providing pilots with speed guidance to achieve a precise interval behind another aircraft, even while flying optimized descents. The Interval Management with Spacing to Parallel Dependent Runways (IMSPiDR) human-in-the-loop experiment employed 24 commercial pilots to explore the use of FIM equipment to conduct spacing operations behind two aircraft arriving to parallel runways, while flying an OPD during high-density operations. This paper describes the impact of variations in pilot operations; in particular configuring the aircraft, their compliance with FIM operating procedures, and their response to changes of the FIM speed. An example of the displayed FIM speeds used incorrectly by a pilot is also discussed. Finally, this paper examines the relationship between achieving airline operational goals for individual aircraft and the need for ATC to deliver aircraft to the runway with greater precision. The results show that aircraft can fly an OPD and conduct FIM operations to dependent parallel runways, enabling operational goals to be achieved efficiently while maintaining system throughput.

Undermatching and overmatching: The fixed-ratio changeover requirement

PubMed Central

Pliskoff, Stanley S.; Fetterman, J. Gregor

1981-01-01

Concurrent variable-interval two-minute and six-minute schedules were arranged while the fixed-ratio changeover requirement was varied among one, two, and four responses. A four-response requirement produced overmatching in the response and time data. A one-response requirement produced consistent undermatching in the time data but mixed results in the response data. The two-response requirement showed undermatching in the time data and overmatching in the response data. The results are discussed in relation to previous research using changeover requirements of five and ten responses, which produced clear tendencies toward overmatching, especially with response data. Taken together, these findings suggest that matching is not a unique result, and that undermatching or overmatching can be produced by continuous variation of the changeover requirements. PMID:16812229

Properties of behavior under different random ratio and random interval schedules: A parametric study.

PubMed

Dembo, M; De Penfold, J B; Ruiz, R; Casalta, H

1985-03-01

Four pigeons were trained to peck a key under different values of a temporally defined independent variable (T) and different probabilities of reinforcement (p). Parameter T is a fixed repeating time cycle and p the probability of reinforcement for the first response of each cycle T. Two dependent variables were used: mean response rate and mean postreinforcement pause. For all values of p a critical value for the independent variable T was found (T=1 sec) in which marked changes took place in response rate and postreinforcement pauses. Behavior typical of random ratio schedules was obtained at T 1 sec and behavior typical of random interval schedules at T 1 sec. Copyright © 1985. Published by Elsevier B.V.

An optics-based variable-temperature assay system for characterizing thermodynamics of biomolecular reactions on solid support

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fei, Yiyan; Landry, James P.; Zhu, X. D., E-mail: xdzhu@physics.ucdavis.edu

A biological state is equilibrium of multiple concurrent biomolecular reactions. The relative importance of these reactions depends on physiological temperature typically between 10 °C and 50 °C. Experimentally the temperature dependence of binding reaction constants reveals thermodynamics and thus details of these biomolecular processes. We developed a variable-temperature opto-fluidic system for real-time measurement of multiple (400–10 000) biomolecular binding reactions on solid supports from 10 °C to 60 °C within ±0.1 °C. We illustrate the performance of this system with investigation of binding reactions of plant lectins (carbohydrate-binding proteins) with 24 synthetic glycans (i.e., carbohydrates). We found that the lectin-glycan reactions in general can be enthalpy-driven,more » entropy-driven, or both, and water molecules play critical roles in the thermodynamics of these reactions.« less

An optics-based variable-temperature assay system for characterizing thermodynamics of biomolecular reactions on solid support

NASA Astrophysics Data System (ADS)

Fei, Yiyan; Landry, James P.; Li, Yanhong; Yu, Hai; Lau, Kam; Huang, Shengshu; Chokhawala, Harshal A.; Chen, Xi; Zhu, X. D.

2013-11-01

A biological state is equilibrium of multiple concurrent biomolecular reactions. The relative importance of these reactions depends on physiological temperature typically between 10 °C and 50 °C. Experimentally the temperature dependence of binding reaction constants reveals thermodynamics and thus details of these biomolecular processes. We developed a variable-temperature opto-fluidic system for real-time measurement of multiple (400-10 000) biomolecular binding reactions on solid supports from 10 °C to 60 °C within ±0.1 °C. We illustrate the performance of this system with investigation of binding reactions of plant lectins (carbohydrate-binding proteins) with 24 synthetic glycans (i.e., carbohydrates). We found that the lectin-glycan reactions in general can be enthalpy-driven, entropy-driven, or both, and water molecules play critical roles in the thermodynamics of these reactions.

A comparison of psychotic symptoms in subjects with methamphetamine versus cocaine dependence.

PubMed

Alexander, Peter D; Gicas, Kristina M; Willi, Taylor S; Kim, Clara N; Boyeva, Veronika; Procyshyn, Ric M; Smith, Geoff N; Thornton, Allen E; Panenka, William J; Jones, Andrea A; Vila-Rodriguez, Fidel; Lang, Donna J; William MacEwan, G; Honer, William G; Barr, Alasdair M

2017-05-01

The psychostimulant drugs cocaine and methamphetamine are potent indirect dopamine receptor agonists which act through similar but not identical mechanisms. Studies in humans have observed that a large proportion of those who chronically use these drugs experience psychotic symptoms. However, direct comparisons of psychotic symptom severity between cocaine and methamphetamine users are lacking. The goal of the present study was to directly compare severity of psychotic symptoms between cocaine- and methamphetamine-dependent individuals. Additionally, we sought to determine how concurrent cocaine + methamphetamine dependence would influence psychotic symptoms. We recruited 153 polysubstance-using subjects meeting DSM-IV-TR criteria for cocaine dependence, 38 with methamphetamine dependence, and 32 with cocaine + methamphetamine dependence. Psychotic symptoms were assessed with the Positive and Negative Syndrome Scale (PANSS) and analyzed using a five-factor model. All participants were also assessed for physical and mental illnesses as well as recent substance use. Most subjects completed a comprehensive neurocognitive battery. While all three groups exhibited high total PANSS scores, the positive symptom subscale was significantly higher in the methamphetamine-dependent (17.03 ± 6.3) than the cocaine-dependent group (13.51 ± 4.12) and non-significantly higher (p = 0.08) than the cocaine + methamphetamine group (14.44 ± 5.50). Groups also differed on demographic variables, viral infection, and other indices of substance use, which were unlikely to account for the difference in positive symptoms. There were only modest differences between groups in neurocognitive function. Methamphetamine dependence was associated with more severe positive symptoms of psychosis than cocaine dependence. Concurrent cocaine + methamphetamine dependence did not increase psychosis severity.

Outcome-Dependent Sampling with Interval-Censored Failure Time Data

PubMed Central

Zhou, Qingning; Cai, Jianwen; Zhou, Haibo

2017-01-01

Summary Epidemiologic studies and disease prevention trials often seek to relate an exposure variable to a failure time that suffers from interval-censoring. When the failure rate is low and the time intervals are wide, a large cohort is often required so as to yield reliable precision on the exposure-failure-time relationship. However, large cohort studies with simple random sampling could be prohibitive for investigators with a limited budget, especially when the exposure variables are expensive to obtain. Alternative cost-effective sampling designs and inference procedures are therefore desirable. We propose an outcome-dependent sampling (ODS) design with interval-censored failure time data, where we enrich the observed sample by selectively including certain more informative failure subjects. We develop a novel sieve semiparametric maximum empirical likelihood approach for fitting the proportional hazards model to data from the proposed interval-censoring ODS design. This approach employs the empirical likelihood and sieve methods to deal with the infinite-dimensional nuisance parameters, which greatly reduces the dimensionality of the estimation problem and eases the computation difficulty. The consistency and asymptotic normality of the resulting regression parameter estimator are established. The results from our extensive simulation study show that the proposed design and method works well for practical situations and is more efficient than the alternative designs and competing approaches. An example from the Atherosclerosis Risk in Communities (ARIC) study is provided for illustration. PMID:28771664

Genetic and Environmental Influences on the Associations Between Uric Acid Levels and Metabolic Syndrome Over Time.

PubMed

Song, Yun-Mi; Lee, Kayoung

2018-05-02

The longitudinal associations between serum uric acid (UA) levels and metabolic syndrome (MetS) and its components, as well as the shared genetic and environmental correlations between these traits, were evaluated. In a total of 1803 participants (675 men and 1128 women; 695 monozygotic twin individuals, 159 dizygotic twin individuals, and 949 non-twin family members; 44.3 ± 12.8 years old) and 321 monozygotic twin pairs with data on UA levels and MetS components at baseline and follow-up, mixed linear model, conditional logistic regression, and bivariate variance component analysis were conducted. After 3.7 ± 1.4 years, the incident and persistent prevalence of MetS were 5.3% and 11.6%, respectively. UA was positively associated with the concurrent and future number of MetS criteria, blood pressure (BP), and triglyceride (TG) levels, whereas an inverse association was observed between UA and future high-density lipoprotein cholesterol (HDL-C) levels after adjusting for twin and household effects, demographics, health behaviors at baseline, and other confounders according to outcome variables. In the adjusted bivariate analysis, UA had genetic and environmental correlations with the concurrent and future number of MetS criteria, and had genetic correlations with concurrent BP and TG levels and future diastolic BP and HDL-C levels. In the adjusted co-twin control analysis, twins with a higher UA level were more likely to have concurrent MetS [odds ratio (95% confidence interval) 1.59 (1.00-2.53)], high blood glucose levels [1.84 (1.06-3.17)], future MetS [2.35 (1.19-4.64)], and high TG levels [1.52 (1.03-2.24)] than co-twins with a lower UA level. Genetic and environmental factors affect the concurrent and longitudinal associations between UA and MetS as well as some of its components.

Using Concurrent Verbalization to Measure Math Comprehension

ERIC Educational Resources Information Center

Lambeth, Cathryn Colley

2012-01-01

The current study investigated variability in student performance on a concurrent verbalization measure based on a grade-level sample math word problem and sought to determine to what extent the variability in verbalization scores is related to scores on a reliable measure of reading (DIBELS Next) and math (easyCBM) and to student factors (e.g.…

A Variable Oscillator Underlies the Measurement of Time Intervals in the Rostral Medial Prefrontal Cortex during Classical Eyeblink Conditioning in Rabbits.

PubMed

Caro-Martín, C Rocío; Leal-Campanario, Rocío; Sánchez-Campusano, Raudel; Delgado-García, José M; Gruart, Agnès

2015-11-04

We were interested in determining whether rostral medial prefrontal cortex (rmPFC) neurons participate in the measurement of conditioned stimulus-unconditioned stimulus (CS-US) time intervals during classical eyeblink conditioning. Rabbits were conditioned with a delay paradigm consisting of a tone as CS. The CS started 50, 250, 500, 1000, or 2000 ms before and coterminated with an air puff (100 ms) directed at the cornea as the US. Eyelid movements were recorded with the magnetic search coil technique and the EMG activity of the orbicularis oculi muscle. Firing activities of rmPFC neurons were recorded across conditioning sessions. Reflex and conditioned eyelid responses presented a dominant oscillatory frequency of ≈12 Hz. The firing rate of each recorded neuron presented a single peak of activity with a frequency dependent on the CS-US interval (i.e., ≈12 Hz for 250 ms, ≈6 Hz for 500 ms, and≈3 Hz for 1000 ms). Interestingly, rmPFC neurons presented their dominant firing peaks at three precise times evenly distributed with respect to CS start and also depending on the duration of the CS-US interval (only for intervals of 250, 500, and 1000 ms). No significant neural responses were recorded at very short (50 ms) or long (2000 ms) CS-US intervals. rmPFC neurons seem not to encode the oscillatory properties characterizing conditioned eyelid responses in rabbits, but are probably involved in the determination of CS-US intervals of an intermediate range (250-1000 ms). We propose that a variable oscillator underlies the generation of working memories in rabbits. The way in which brains generate working memories (those used for the transient processing and storage of newly acquired information) is still an intriguing question. Here, we report that the firing activities of neurons located in the rostromedial prefrontal cortex recorded in alert behaving rabbits are controlled by a dynamic oscillator. This oscillator generated firing frequencies in a variable band of 3-12 Hz depending on the conditioned stimulus-unconditioned stimulus intervals (1 s, 500 ms, 250 ms) selected for classical eyeblink conditioning of behaving rabbits. Shorter (50 ms) and longer (2 s) intervals failed to activate the oscillator and prevented the acquisition of conditioned eyelid responses. This is an unexpected mechanism to generate sustained firing activities in neural circuits generating working memories. Copyright © 2015 the authors 0270-6474/15/3514809-13$15.00/0.

Body weight concerns: Cross-national study and identification of factors related to eating disorders

PubMed Central

da Silva, Wanderson Roberto; Santana, Moema de Souza; Maroco, João; Maloa, Benvindo Felismino Samuel

2017-01-01

Background Body weight concerns are common among individuals with eating disorders, and this construct can be assessed using psychometric instruments. The Weight Concerns Scale (WCS) is commonly used to assess body weight concerns. Aims To evaluate the psychometric properties of the WCS with Brazilian, Portuguese, and Mozambican female college students; to estimate body weight concerns; and to identify factors related to eating disorders. Methods Confirmatory factor analysis was performed. Factorial, convergent, concurrent, and divergent validity, as well as reliability, were assessed. Cross-national invariance was tested by means of multigroup analysis. Structural models were tested using the WCS as the dependent variable, while demographic and academic variables and body mass index were used as independent variables. Logistic models were tested to estimate the likelihood of eating disorders being developed in specific groups. Results Participants were 2,068 female students. The psychometric properties of the WCS were adequate for the Portuguese sample; however, for the Brazilian and Mozambican samples, it was necessary to correlate the errors of two items to improve model fit. The WCS did not show cross-national invariance. The variables “thoughts about dropping out of college,” “medication use because of studies,” “medication and supplements use for body change,” “body mass index,” “socioeconomic status,” “age,” and “performance in course” were significant predictors of body weight concerns. Overall, 24.4% (95% confidence interval = 22.9–26.7) of the students were likely to develop eating disorders. Students under 21 years old, who use medication and supplements for body change, and who were classified as overweight/obese have increased likelihood of developing eating disorders. Conclusion The WCS showed good psychometric properties with Brazilian, Portuguese, and Mozambican students; however, it did not show cross-national invariance. We identified important aspects for investigating body weight concerns and factors related to eating disorders. PMID:28686602

More accurate, calibrated bootstrap confidence intervals for correlating two autocorrelated climate time series

NASA Astrophysics Data System (ADS)

Olafsdottir, Kristin B.; Mudelsee, Manfred

2013-04-01

Estimation of the Pearson's correlation coefficient between two time series to evaluate the influences of one time depended variable on another is one of the most often used statistical method in climate sciences. Various methods are used to estimate confidence interval to support the correlation point estimate. Many of them make strong mathematical assumptions regarding distributional shape and serial correlation, which are rarely met. More robust statistical methods are needed to increase the accuracy of the confidence intervals. Bootstrap confidence intervals are estimated in the Fortran 90 program PearsonT (Mudelsee, 2003), where the main intention was to get an accurate confidence interval for correlation coefficient between two time series by taking the serial dependence of the process that generated the data into account. However, Monte Carlo experiments show that the coverage accuracy for smaller data sizes can be improved. Here we adapt the PearsonT program into a new version called PearsonT3, by calibrating the confidence interval to increase the coverage accuracy. Calibration is a bootstrap resampling technique, which basically performs a second bootstrap loop or resamples from the bootstrap resamples. It offers, like the non-calibrated bootstrap confidence intervals, robustness against the data distribution. Pairwise moving block bootstrap is used to preserve the serial correlation of both time series. The calibration is applied to standard error based bootstrap Student's t confidence intervals. The performances of the calibrated confidence intervals are examined with Monte Carlo simulations, and compared with the performances of confidence intervals without calibration, that is, PearsonT. The coverage accuracy is evidently better for the calibrated confidence intervals where the coverage error is acceptably small (i.e., within a few percentage points) already for data sizes as small as 20. One form of climate time series is output from numerical models which simulate the climate system. The method is applied to model data from the high resolution ocean model, INALT01 where the relationship between the Agulhas Leakage and the North Brazil Current is evaluated. Preliminary results show significant correlation between the two variables when there is 10 year lag between them, which is more or less the time that takes the Agulhas Leakage water to reach the North Brazil Current. Mudelsee, M., 2003. Estimating Pearson's correlation coefficient with bootstrap confidence interval from serially dependent time series. Mathematical Geology 35, 651-665.

Effects of Simultaneous or Sequential Weight Loss Diet and Aerobic Interval Training on Metabolic Syndrome.

PubMed

Mora-Rodriguez, R; Ortega, J F; Guio de Prada, V; Fernández-Elías, V E; Hamouti, N; Morales-Palomo, F; Martinez-Vizcaino, V; Nelson, R K

2016-04-01

Our purpose in this study was to investigate efficient and sustainable combinations of exercise and diet-induced weight loss (DIET), in order to combat obesity in metabolic syndrome (MetS) patients. We examined the impact of aerobic interval training (AIT), followed by or concurrent to a DIET on MetS components. 36 MetS patients (54±9 years old; 33±4 BMI; 27 males and 9 females) underwent 16 weeks of AIT followed by another 16 weeks without exercise from the fall of 2013 to the spring of 2014. Participants were randomized to AIT without DIET (E CON, n=12), AIT followed by DIET (E-then-D, n=12) or AIT concurrent with DIET (E+D, n=12) groups. Body weight decreased below E CON similarly in the E-then-D and E+D groups (~5%). Training improved blood pressure and cardiorespiratory fitness (VO2peak) in all groups with no additional effect of concurrent weight loss. However, E+D improved insulin sensitivity (HOMA) and lowered plasma triglycerides and blood cholesterol below E CON and E-then-D (all P<0.05). Weight loss in E-then-D in the 16 weeks without exercise lowered HOMA to the E+D levels and maintained blood pressure at trained levels. Our data suggest that a new lifestyle combination consisting of aerobic interval training followed by weight loss diet is similar, or even more effective on improving metabolic syndrome factors than concurrent exercise plus diet. © Georg Thieme Verlag KG Stuttgart · New York.

Effects of age, task, and frequency on variability of finger tapping.

PubMed

Sommervoll, Yngve; Ettema, Gertjan; Vereijken, Beatrix

2011-10-01

The goal was to assess whether prior studies might have overestimated performance variability in older adults in dual task conditions by relying on primary motor tasks that are not constant with aging. 30 younger and 31 older adults performed a bimanual tapping task at four different frequencies in isolation or concurrently with a secondary task. Results showed that performance of younger and older adults was not significantly different in performing the tapping task at all frequencies and with either secondary task, as indicated by mean tapping performance and low number of errors in the secondary tasks. Both groups showed increased variability as tapping frequency increased and with the presence of a secondary task. Tapping concurrently while reading words increased tapping variability more than tapping concurrently while naming colours. Although older participants' performances were overall more variable, no interaction effects with age were found and at the highest frequencies of tapping, younger and older participants did not differ in performance.

Interactions between CO2 chemoreflexes and arterial baroreflexes

NASA Technical Reports Server (NTRS)

Henry, R. A.; Lu, I. L.; Beightol, L. A.; Eckberg, D. L.

1998-01-01

We studied interactions between CO2 chemoreflexes and arterial baroreflexes in 10 supine healthy young men and women. We measured vagal carotid baroreceptor-cardiac reflexes and steady-state fast Fourier transform R-R interval and photoplethysmographic arterial pressure power spectra at three arterial pressure levels (nitroprusside, saline, and phenylephrine infusions) and three end-tidal CO2 levels (3, 4, and 5%, fixed-frequency, large-tidal-volume breathing, CO2 plus O2). Our study supports three principal conclusions. First, although low levels of CO2 chemoreceptor stimulation reduce R-R intervals and R-R interval variability, statistical modeling suggests that this effect is indirect rather than direct and is mediated by reductions of arterial pressure. Second, reductions of R-R intervals during hypocapnia reflect simple shifting of vagally mediated carotid baroreflex responses on the R-R interval axis rather than changes of baroreflex gain, range, or operational point. Third, the influence of CO2 chemoreceptor stimulation on arterial pressure (and, derivatively, on R-R intervals and R-R interval variability) depends critically on baseline arterial pressure levels: chemoreceptor effects are smaller when pressure is low and larger when arterial pressure is high.

Estimating degradation in real time and accelerated stability tests with random lot-to-lot variation: a simulation study.

PubMed

Magari, Robert T

2002-03-01

The effect of different lot-to-lot variability levels on the prediction of stability are studied based on two statistical models for estimating degradation in real time and accelerated stability tests. Lot-to-lot variability is considered as random in both models, and is attributed to two sources-variability at time zero, and variability of degradation rate. Real-time stability tests are modeled as a function of time while accelerated stability tests as a function of time and temperatures. Several data sets were simulated, and a maximum likelihood approach was used for estimation. The 95% confidence intervals for the degradation rate depend on the amount of lot-to-lot variability. When lot-to-lot degradation rate variability is relatively large (CV > or = 8%) the estimated confidence intervals do not represent the trend for individual lots. In such cases it is recommended to analyze each lot individually. Copyright 2002 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 91: 893-899, 2002

Self-controlled concurrent feedback facilitates the learning of the final approach phase in a fixed-base flight simulator.

PubMed

Huet, Michaël; Jacobs, David M; Camachon, Cyril; Goulon, Cedric; Montagne, Gilles

2009-12-01

This study (a) compares the effectiveness of different types of feedback for novices who learn to land a virtual aircraft in a fixed-base flight simulator and (b) analyzes the informational variables that learners come to use after practice. An extensive body of research exists concerning the informational variables that allow successful landing. In contrast, few studies have examined how the attention of pilots can be directed toward these sources of information. In this study, 15 participants were asked to land a virtual Cessna 172 on 245 trials while trying to follow the glide-slope area as accurately as possible. Three groups of participants practiced under different feedback conditions: with self-controlled concurrent feedback (the self-controlled group), with imposed concurrent feedback (the yoked group), or without concurrent feedback (the control group). The self-controlled group outperformed the yoked group, which in turn outperformed the control group. Removing or manipulating specific sources of information during transfer tests had different effects for different individuals. However, removing the cockpit from the visual scene had a detrimental effect on the performance of the majority of the participants. Self-controlled concurrent feedback helps learners to more quickly attune to the informational variables that allow them to control the aircraft during the approach phase. Knowledge concerning feedback schedules can be used for the design of optimal practice methods for student pilots, and knowledge about the informational variables used by expert performers has implications for the design of cockpits and runways that facilitate the detection of these variables.

Employee age and tenure within organizations: relationship to workplace satisfaction and workplace climate perceptions.

PubMed

Teclaw, Robert; Osatuke, Katerine; Fishman, Jonathan; Moore, Scott C; Dyrenforth, Sue

2014-01-01

This study estimated the relative influence of age/generation and tenure on job satisfaction and workplace climate perceptions. Data from the 2004, 2008, and 2012 Veterans Health Administration All Employee Survey (sample sizes >100 000) were examined in general linear models, with demographic characteristics simultaneously included as independent variables. Ten dependent variables represented a broad range of employee attitudes. Age/generation and tenure effects were compared through partial η(2) (95% confidence interval), P value of F statistic, and overall model R(2). Demographic variables taken together were only weakly related to employee attitudes, accounting for less than 10% of the variance. Consistently across survey years, for all dependent variables, age and age-squared had very weak to no effects, whereas tenure and tenure-squared had meaningfully greater partial η(2) values. Except for 1 independent variable in 1 year, none of the partial η(2) confidence intervals for age and age-squared overlapped those of tenure and tenure-squared. Much has been made in the popular and professional press of the importance of generational differences in workplace attitudes. Empirical studies have been contradictory and therefore inconclusive. The findings reported here suggest that age/generational differences might not influence employee perceptions to the extent that human resource and management practitioners have been led to believe.

General Multimechanism Reversible-Irreversible Time-Dependent Constitutive Deformation Model Being Developed

NASA Technical Reports Server (NTRS)

Saleeb, A. F.; Arnold, Steven M.

2001-01-01

Since most advanced material systems (for example metallic-, polymer-, and ceramic-based systems) being currently researched and evaluated are for high-temperature airframe and propulsion system applications, the required constitutive models must account for both reversible and irreversible time-dependent deformations. Furthermore, since an integral part of continuum-based computational methodologies (be they microscale- or macroscale-based) is an accurate and computationally efficient constitutive model to describe the deformation behavior of the materials of interest, extensive research efforts have been made over the years on the phenomenological representations of constitutive material behavior in the inelastic analysis of structures. From a more recent and comprehensive perspective, the NASA Glenn Research Center in conjunction with the University of Akron has emphasized concurrently addressing three important and related areas: that is, 1) Mathematical formulation; 2) Algorithmic developments for updating (integrating) the external (e.g., stress) and internal state variables; 3) Parameter estimation for characterizing the model. This concurrent perspective to constitutive modeling has enabled the overcoming of the two major obstacles to fully utilizing these sophisticated time-dependent (hereditary) constitutive models in practical engineering analysis. These obstacles are: 1) Lack of efficient and robust integration algorithms; 2) Difficulties associated with characterizing the large number of required material parameters, particularly when many of these parameters lack obvious or direct physical interpretations.

Anger, anxiety, and depressive affect as predictors of stress-induced cortisol production in khat and tobacco users.

PubMed

Lemieux, Andrine M; Nakajima, Motohiro; Saif-Ali, Riyadh; Al-Habori, Molham; Dokam, Anisa; al'Absi, Mustafa

2018-07-01

Glucocorticoid activity is disrupted in substance users including khat chewers who also use tobacco. Anger, dysphoria, and anxiety can mediate this relationship. The aim of this study was to contrast emotion dysregulation and substance use variables as predictors of post-stress cortisol output. Comparable numbers of males (n = 90) and females (n = 85) including controls, khat only, and concurrent khat and tobacco users participated in a stress study. Depressive affect, anxiety, anger, substance use patterns, and saliva samples were collected following a standardized laboratory stress manipulation. Regression analysis showed that high depression and low anxiety was associated with high post-stress cortisol, but only in co-users of tobacco and khat. Males, but not females, showed a significant association between co-use of khat and tobacco and cortisol, which appears to be mediated by frequency of use. The link between anxiety and post-stress cortisol in the co-users remained significant after controlling for nicotine dependence and substance use frequency. Anxiety predicted the neuroendocrine consequences of concurrent use of tobacco and khat above and beyond sex, nicotine dependence, anger, and substance use frequency. Sex differences, however, are related to differences in nicotine dependence. Copyright © 2018. Published by Elsevier Ltd.

Is Perruchet's dissociation between eyeblink conditioned responding and outcome expectancy evidence for two learning systems?

PubMed

Weidemann, Gabrielle; Tangen, Jason M; Lovibond, Peter F; Mitchell, Christopher J

2009-04-01

P. Perruchet (1985b) showed a double dissociation of conditioned responses (CRs) and expectancy for an airpuff unconditioned stimulus (US) in a 50% partial reinforcement schedule in human eyeblink conditioning. In the Perruchet effect, participants show an increase in CRs and a concurrent decrease in expectancy for the airpuff across runs of reinforced trials; conversely, participants show a decrease in CRs and a concurrent increase in expectancy for the airpuff across runs of nonreinforced trials. Three eyeblink conditioning experiments investigated whether the linear trend in eyeblink CRs in the Perruchet effect is a result of changes in associative strength of the conditioned stimulus (CS), US sensitization, or learning the precise timing of the US. Experiments 1 and 2 demonstrated that the linear trend in eyeblink CRs is not the result of US sensitization. Experiment 3 showed that the linear trend in eyeblink CRs is present with both a fixed and a variable CS-US interval and so is not the result of learning the precise timing of the US. The results are difficult to reconcile with a single learning process model of associative learning in which expectancy mediates CRs. Copyright (c) 2009 APA, all rights reserved.

Low-flow-frequency characteristics for continuous-record streamflow stations in Minnesota

USGS Publications Warehouse

Arntson, A.D.; Lorenz, D.L.

1987-01-01

Annual and summer (May 1 to September 30) low-flow frequency curves are presented for 175 continuous-record streamflow stations in Minnesota. The curves were developed for all stations with 10 or more years of continuous record. The 1-, 7-, and 30-day low-flow discharges at selected recurrence intervals obtained from these curves are listed. Low-flow characteristics can and will vary for a station depending upon the number of years of record and the period gaged. When comparing low-flow characteristics between two or more stations, it should be remembered that no provisions were made to use concurrent periods of record for stations along the same stream.

Concurrent crack and powder cocaine users from Sao Paulo: Do they represent a different group?

PubMed Central

Guindalini, Camila; Vallada, Homero; Breen, Gerome; Laranjeira, Ronaldo

2006-01-01

Background Cocaine abuse is a serious and socially damaging illegal drug problem. Different routes of administration are associated with a specific progression of use, different degrees of abuse liability, propensity for dependence and treatment response. There have been relatively few studies comparing different cocaine users groups and no studies into the characterization of the group of individuals reporting concurrent use of powder cocaine and crack cocaine. Methods Six hundred and ninety-nine cocaine users were assessed during the period August 1997 to October 1998 in one outpatient and six inpatient clinics located in the São Paulo, Brazil. Patients were interviewed using a structured questionnaire schedule in Portuguese, designed specifically for the Brazilian population. The statistical analyses were performed using either ANOVA or a chi-squared test and focusing on their preferred form of use/route of administration and other variables. Results For 83% of the variables tested in this study, the Dual Users subgroup (using both powder and crack cocaine) demonstrated statistical differences from the single drug user subgroups. Those differences include the initiation of cocaine, the abuse of other illicit drugs, and rates of criminal history. Conclusion These data suggest cocaine-dependent individuals who report use of both powder and crack cocaine are an at least partially, distinct subgroup. However, further studies will be necessary to confirm this and to determine if they also show a different treatment response. PMID:16426451

Influence of temporal context on value in the multiple-chains and successive-encounters procedures.

PubMed

O'Daly, Matthew; Angulo, Samuel; Gipson, Cassandra; Fantino, Edmund

2006-05-01

This set of studies explored the influence of temporal context across multiple-chain and multiple-successive-encounters procedures. Following training with different temporal contexts, the value of stimuli sharing similar reinforcement schedules was assessed by presenting these stimuli in concurrent probes. The results for the multiple-chain schedule indicate that temporal context does impact the value of a conditioned reinforcer consistent with delay-reduction theory, such that a stimulus signaling a greater reduction in delay until reinforcement has greater value. Further, nonreinforced stimuli that are concurrently presented with the preferred terminal link also have greater value, consistent with value transfer. The effects of context on value for conditions with the multiple-successive-encounters procedure, however, appear to depend on whether the search schedule or alternate handling schedule was manipulated, as well as on whether the tested stimuli were the rich or lean schedules in their components. Overall, the results help delineate the conditions under which temporal context affects conditioned-reinforcement value (acting as a learning variable) and the conditions under which it does not (acting as a performance variable), an issue of relevance to theories of choice.

Some implications for the clinical use of music facilitated imagery.

PubMed

Peach, S C

1984-01-01

In this study, Helen Bonny's Guided Imagery and Music technique provided the base experience for questionnaire responses from short-term psychiatric inpatients, students, and staff (total/n = 107). Independent measures of age range, sex, medication type, and recent relaxation practice were compared statistically with dependent responses of skin temperature, perceived ability to relax, production of images, and perceived helpfulness of the experience. Results demonstrated increases in skin temperature and relaxation perception and defined the average experience as manifesting three concurrent imagery modes. Among the man independent-dependent variable relationships, some significant differences in mean responses were present. These differences and their possible clinical implications are discussed; further research in the area, including replication, is recommended.

Mechanisms underlying very-low-frequency RR-interval oscillations in humans

NASA Technical Reports Server (NTRS)

Taylor, J. A.; Carr, D. L.; Myers, C. W.; Eckberg, D. L.

1998-01-01

BACKGROUND: Survival of post-myocardial infarction patients is related inversely to their levels of very-low-frequency (0.003 to 0.03 Hz) RR-interval variability. The physiological basis for such oscillations is unclear. In our study, we used blocking drugs to evaluate potential contributions of sympathetic and vagal mechanisms and the renin-angiotensin-aldosterone system to very-low-frequency RR-interval variability in 10 young healthy subjects. METHODS AND RESULTS: We recorded RR intervals and arterial pressures during three separate sessions, with the patient in supine and 40 degree upright tilt positions, during 20-minute frequency (0.25 Hz) and tidal volume-controlled breathing after intravenous injections: saline (control), atenolol (0.2 mg/kg, beta-adrenergic blockade), atropine sulfate (0.04 mg/kg, parasympathetic blockade), atenolol and atropine (complete autonomic blockade), and enalaprilat (0.02 mg/kg, ACE blockade). We integrated fast Fourier transform RR-interval spectral power at very low (0.003 to 0.03 Hz), low (0.05 to 0. 15 Hz), and respiratory (0.2 to 0.3 Hz) frequencies. Beta-adrenergic blockade had no significant effect on very-low- or low-frequency RR-interval power but increased respiratory frequency power 2-fold. ACE blockade had no significant effect on low or respiratory frequency RR-interval power but modestly (approximately 21%) increased very-low-frequency power in the supine (but not upright tilt) position (P<0.05). The most profound effects were exerted by parasympathetic blockade: Atropine, given alone or with atenolol, abolished nearly all RR-interval variability and decreased very-low-frequency variability by 92%. CONCLUSIONS: Although very-low-frequency heart period rhythms are influenced by the renin-angiotensin-aldosterone system, as low and respiratory frequency RR-interval rhythms, they depend primarily on the presence of parasympathetic outflow. Therefore the prognostic value of very-low-frequency heart period oscillations may derive from the fundamental importance of parasympathetic mechanisms in cardiovascular health.

Reasoning about real-time systems with temporal interval logic constraints on multi-state automata

NASA Technical Reports Server (NTRS)

Gabrielian, Armen

1991-01-01

Models of real-time systems using a single paradigm often turn out to be inadequate, whether the paradigm is based on states, rules, event sequences, or logic. A model-based approach to reasoning about real-time systems is presented in which a temporal interval logic called TIL is employed to define constraints on a new type of high level automata. The combination, called hierarchical multi-state (HMS) machines, can be used to model formally a real-time system, a dynamic set of requirements, the environment, heuristic knowledge about planning-related problem solving, and the computational states of the reasoning mechanism. In this framework, mathematical techniques were developed for: (1) proving the correctness of a representation; (2) planning of concurrent tasks to achieve goals; and (3) scheduling of plans to satisfy complex temporal constraints. HMS machines allow reasoning about a real-time system from a model of how truth arises instead of merely depending of what is true in a system.

Chlamydia trachomatis infection in young adults - association with concurrent partnerships and short gap length between partners.

PubMed

Jørgensen, Marianne Johansson; Maindal, Helle Terkildsen; Larsen, Mette Bach; Christensen, Kaj Sparle; Olesen, Frede; Andersen, Berit

2015-01-01

Sexually transmitted infections (STIs) continue to be highly prevalent in young people. New understanding of sexual risk behaviour is essential for future preventive initiatives. Studies based on self-reported STI history indicate that gap length between sexual partnerships is an important determinant in STI transmission, but little is known about the impact of concurrent partnerships and short gap length. This study aimed to examine the significance of concurrent partnerships and short gap length between serially monogamous partnerships in Chlamydia trachomatis-infected individuals compared to the general population. A Danish cross-sectional study was conducted among individuals aged 15-29 years with a verified C. trachomatis infection and a sample of the background population. Participants answered a web-based questionnaire on sexual behaviour. Associations were identified in multivariate analyses. In total, 36% of the included young adults reported that they had two or more partners within the last year. Concurrent partnerships were frequent (46%), and the gap length between serially monogamous partnerships tended to be short (median gap length, 64 days, interquartile interval (IQI) = 31, 122). A strong association was found between concurrent partnerships (odds ratio (OR) = 12.5, 95% confidence interval (CI) = 7.7-20.4), short gap length between serially monogamous partnerships (OR = 10.0, 95% CI = 5.7-17.4) and having a verified C. trachomatis infection. C. trachomatis infection was strongly associated with concurrent partnerships or short gap length between serially monogamous partnerships. These findings have considerable implications for public health policy. Both types of risk factors should be considered in future preventive interventions aiming to reduce the spread of C. trachomatis infections.

Evaluating dedicated and intrinsic models of temporal encoding by varying context

PubMed Central

Spencer, Rebecca M.C.; Karmarkar, Uma; Ivry, Richard B.

2009-01-01

Two general classes of models have been proposed to account for how people process temporal information in the milliseconds range. Dedicated models entail a mechanism in which time is explicitly encoded; examples include clock–counter models and functional delay lines. Intrinsic models, such as state-dependent networks (SDN), represent time as an emergent property of the dynamics of neural processing. An important property of SDN is that the encoding of duration is context dependent since the representation of an interval will vary as a function of the initial state of the network. Consistent with this assumption, duration discrimination thresholds for auditory intervals spanning 100 ms are elevated when an irrelevant tone is presented at varying times prior to the onset of the test interval. We revisit this effect in two experiments, considering attentional issues that may also produce such context effects. The disruptive effect of a variable context was eliminated or attenuated when the intervals between the irrelevant tone and test interval were made dissimilar or the duration of the test interval was increased to 300 ms. These results indicate how attentional processes can influence the perception of brief intervals, as well as point to important constraints for SDN models. PMID:19487188

Using complexity metrics with R-R intervals and BPM heart rate measures.

PubMed

Wallot, Sebastian; Fusaroli, Riccardo; Tylén, Kristian; Jegindø, Else-Marie

2013-01-01

Lately, growing attention in the health sciences has been paid to the dynamics of heart rate as indicator of impending failures and for prognoses. Likewise, in social and cognitive sciences, heart rate is increasingly employed as a measure of arousal, emotional engagement and as a marker of interpersonal coordination. However, there is no consensus about which measurements and analytical tools are most appropriate in mapping the temporal dynamics of heart rate and quite different metrics are reported in the literature. As complexity metrics of heart rate variability depend critically on variability of the data, different choices regarding the kind of measures can have a substantial impact on the results. In this article we compare linear and non-linear statistics on two prominent types of heart beat data, beat-to-beat intervals (R-R interval) and beats-per-min (BPM). As a proof-of-concept, we employ a simple rest-exercise-rest task and show that non-linear statistics-fractal (DFA) and recurrence (RQA) analyses-reveal information about heart beat activity above and beyond the simple level of heart rate. Non-linear statistics unveil sustained post-exercise effects on heart rate dynamics, but their power to do so critically depends on the type data that is employed: While R-R intervals are very susceptible to non-linear analyses, the success of non-linear methods for BPM data critically depends on their construction. Generally, "oversampled" BPM time-series can be recommended as they retain most of the information about non-linear aspects of heart beat dynamics.

Using complexity metrics with R-R intervals and BPM heart rate measures

PubMed Central

Wallot, Sebastian; Fusaroli, Riccardo; Tylén, Kristian; Jegindø, Else-Marie

2013-01-01

Lately, growing attention in the health sciences has been paid to the dynamics of heart rate as indicator of impending failures and for prognoses. Likewise, in social and cognitive sciences, heart rate is increasingly employed as a measure of arousal, emotional engagement and as a marker of interpersonal coordination. However, there is no consensus about which measurements and analytical tools are most appropriate in mapping the temporal dynamics of heart rate and quite different metrics are reported in the literature. As complexity metrics of heart rate variability depend critically on variability of the data, different choices regarding the kind of measures can have a substantial impact on the results. In this article we compare linear and non-linear statistics on two prominent types of heart beat data, beat-to-beat intervals (R-R interval) and beats-per-min (BPM). As a proof-of-concept, we employ a simple rest-exercise-rest task and show that non-linear statistics—fractal (DFA) and recurrence (RQA) analyses—reveal information about heart beat activity above and beyond the simple level of heart rate. Non-linear statistics unveil sustained post-exercise effects on heart rate dynamics, but their power to do so critically depends on the type data that is employed: While R-R intervals are very susceptible to non-linear analyses, the success of non-linear methods for BPM data critically depends on their construction. Generally, “oversampled” BPM time-series can be recommended as they retain most of the information about non-linear aspects of heart beat dynamics. PMID:23964244

Semiparametric regression analysis of failure time data with dependent interval censoring.

PubMed

Chen, Chyong-Mei; Shen, Pao-Sheng

2017-09-20

Interval-censored failure-time data arise when subjects are examined or observed periodically such that the failure time of interest is not examined exactly but only known to be bracketed between two adjacent observation times. The commonly used approaches assume that the examination times and the failure time are independent or conditionally independent given covariates. In many practical applications, patients who are already in poor health or have a weak immune system before treatment usually tend to visit physicians more often after treatment than those with better health or immune system. In this situation, the visiting rate is positively correlated with the risk of failure due to the health status, which results in dependent interval-censored data. While some measurable factors affecting health status such as age, gender, and physical symptom can be included in the covariates, some health-related latent variables cannot be observed or measured. To deal with dependent interval censoring involving unobserved latent variable, we characterize the visiting/examination process as recurrent event process and propose a joint frailty model to account for the association of the failure time and visiting process. A shared gamma frailty is incorporated into the Cox model and proportional intensity model for the failure time and visiting process, respectively, in a multiplicative way. We propose a semiparametric maximum likelihood approach for estimating model parameters and show the asymptotic properties, including consistency and weak convergence. Extensive simulation studies are conducted and a data set of bladder cancer is analyzed for illustrative purposes. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Motor and Executive Control in Repetitive Timing of Brief Intervals

ERIC Educational Resources Information Center

Holm, Linus; Ullen, Fredrik; Madison, Guy

2013-01-01

We investigated the causal role of executive control functions in the production of brief time intervals by means of a concurrent task paradigm. To isolate the influence of executive functions on timing from motor coordination effects, we dissociated executive load from the number of effectors used in the dual task situation. In 3 experiments,…

Evaluating a Computer Flash-Card Sight-Word Recognition Intervention with Self-Determined Response Intervals in Elementary Students with Intellectual Disability

ERIC Educational Resources Information Center

Cazzell, Samantha; Skinner, Christopher H.; Ciancio, Dennis; Aspiranti, Kathleen; Watson, Tiffany; Taylor, Kala; McCurdy, Merilee; Skinner, Amy

2017-01-01

A concurrent multiple-baseline across-tasks design was used to evaluate the effectiveness of a computer flash-card sight-word recognition intervention with elementary-school students with intellectual disability. This intervention allowed the participants to self-determine each response interval and resulted in both participants acquiring…

The Reliability and Validity of Measures of Gait Variability in Community-Dwelling Older Adults

PubMed Central

Brach, Jennifer S.; Perera, Subashan; Studenski, Stephanie; Newman, Anne B.

2009-01-01

Objective To examine the test-retest reliability and concurrent validity of variability of gait characteristics. Design Cross-sectional study. Setting Research laboratory. Participants Older adults (N=558) from the Cardiovascular Health Study. Interventions Not applicable. Main Outcome Measures Gait characteristics were measured using a 4-m computerized walkway. SD determined from the steps recorded were used as the measures of variability. Intraclass correlation coefficients (ICC) were calculated to examine test-retest reliability of a 4-m walk and two 4-m walks. To establish concurrent validity, the measures of gait variability were compared across levels of health, functional status, and physical activity using independent t tests and analysis of variances. Results Gait variability measures from the two 4-m walks demonstrated greater test-retest reliability than those from the single 4-m walk (ICC=.22–.48 and ICC=.40–.63, respectively). Greater step length and stance time variability were associated with poorer health, functional status and physical activity (P<.05). Conclusions Gait variability calculated from a limited number of steps has fair to good test-retest reliability and concurrent validity. Reliability of gait variability calculated from a greater number of steps should be assessed to determine if the consistency can be improved. PMID:19061741

Increasing accuracy in the interval analysis by the improved format of interval extension based on the first order Taylor series

NASA Astrophysics Data System (ADS)

Li, Yi; Xu, Yan Long

2018-05-01

When the dependence of the function on uncertain variables is non-monotonic in interval, the interval of function obtained by the classic interval extension based on the first order Taylor series will exhibit significant errors. In order to reduce theses errors, the improved format of the interval extension with the first order Taylor series is developed here considering the monotonicity of function. Two typical mathematic examples are given to illustrate this methodology. The vibration of a beam with lumped masses is studied to demonstrate the usefulness of this method in the practical application, and the necessary input data of which are only the function value at the central point of interval, sensitivity and deviation of function. The results of above examples show that the interval of function from the method developed by this paper is more accurate than the ones obtained by the classic method.

Effectiveness of concurrent procedures during high tibial osteotomy for medial compartment osteoarthritis: a systematic review and meta-analysis.

PubMed

Lee, O-Sung; Ahn, Soyeon; Ahn, Jin Hwan; Teo, Seow Hui; Lee, Yong Seuk

2018-02-01

The purpose of this systematic review and meta-analysis was to evaluate the efficacy of concurrent cartilage procedures during high tibial osteotomy (HTO) for medial compartment osteoarthritis (OA) by comparing the outcomes of studies that directly compared the use of HTO plus concurrent cartilage procedures versus HTO alone. Results that are possible to be compared in more than two articles were presented as forest plots. A 95% confidence interval was calculated for each effect size, and we calculated the I 2 statistic, which presents the percentage of total variation attributable to the heterogeneity among studies. The random effects model was used to calculate the effect size. Seven articles were included to the final analysis. Case groups were composed of HTO without concurrent procedures and control groups were composed of HTO with concurrent procedures such as marrow stimulation procedure, mesenchymal stem cell transplantation, and injection. The case group showed a higher hospital for special surgery score and mean difference was 4.10 [I 2 80.8%, 95% confidence interval (CI) - 9.02 to 4.82]. Mean difference of the mechanical femorotibial angle in five studies was 0.08° (I 2 0%, 95% CI - 0.26 to 0.43). However, improved arthroscopic, histologic, and MRI results were reported in the control group. Our analysis support that concurrent procedures during HTO for medial compartment OA have little beneficial effect regarding clinical and radiological outcomes. However, they might have some beneficial effects in terms of arthroscopic, histologic, and MRI findings even though the quality of healed cartilage is not good as that of original cartilage. Therefore, until now, concurrent procedures for medial compartment OA have been considered optional. Nevertheless, no conclusions can be drawn for younger patients with focal cartilage defects and concomitant varus deformity. This question needs to be addressed separately.

Abstract: Inference and Interval Estimation for Indirect Effects With Latent Variable Models.

PubMed

Falk, Carl F; Biesanz, Jeremy C

2011-11-30

Models specifying indirect effects (or mediation) and structural equation modeling are both popular in the social sciences. Yet relatively little research has compared methods that test for indirect effects among latent variables and provided precise estimates of the effectiveness of different methods. This simulation study provides an extensive comparison of methods for constructing confidence intervals and for making inferences about indirect effects with latent variables. We compared the percentile (PC) bootstrap, bias-corrected (BC) bootstrap, bias-corrected accelerated (BC a ) bootstrap, likelihood-based confidence intervals (Neale & Miller, 1997), partial posterior predictive (Biesanz, Falk, and Savalei, 2010), and joint significance tests based on Wald tests or likelihood ratio tests. All models included three reflective latent variables representing the independent, dependent, and mediating variables. The design included the following fully crossed conditions: (a) sample size: 100, 200, and 500; (b) number of indicators per latent variable: 3 versus 5; (c) reliability per set of indicators: .7 versus .9; (d) and 16 different path combinations for the indirect effect (α = 0, .14, .39, or .59; and β = 0, .14, .39, or .59). Simulations were performed using a WestGrid cluster of 1680 3.06GHz Intel Xeon processors running R and OpenMx. Results based on 1,000 replications per cell and 2,000 resamples per bootstrap method indicated that the BC and BC a bootstrap methods have inflated Type I error rates. Likelihood-based confidence intervals and the PC bootstrap emerged as methods that adequately control Type I error and have good coverage rates.

Setting the Revisit Interval in Primary Care

PubMed Central

Schwartz, Lisa M; Woloshin, Steven; Wasson, John H; Renfrew, Roger A; Welch, H Gilbert

1999-01-01

OBJECTIVE Although longitudinal care constitutes the bulk of primary care, physicians receive little guidance on the fundamental question of how to time follow-up visits. We sought to identify important predictors of the revisit interval and to describe the variability in how physicians set these intervals when caring for patients with common medical conditions. DESIGN Cross-sectional survey of physicians performed at the end of office visits for consecutive patients with hypertension, angina, diabetes, or musculoskeletal pain. PARTICIPANTS/SETTING One hundred sixty-four patients under the care of 11 primary care physicians in the Dartmouth Primary Care Cooperative Research Network. MEASUREMENTS The main outcome measures were the variability in mean revisit intervals across physicians and the proportion of explained variance by potential determinants of revisit intervals. We assessed the relation between the revisit interval (dependent variable) and three groups of independent variables, patient characteristics (e.g., age, physician perception of patient health), identification of individual physician, and physician characterization of the visit (e.g., routine visit, visit requiring a change in management, or visit occurring on a “hectic” day), using multiple regression that accounted for the natural grouping of patients within physician. MAIN RESULTS Revisit intervals ranged from 1 week to over 1 year. The most common intervals were 12 and 16 weeks. Physicians’ perception of fair-poor health status and visits involving a change in management were most strongly related to shorter revisit intervals. In multivariate analyses, patient characteristics explained about 18% of the variance in revisit intervals, and adding identification of the individual provider doubled the explained variance to about 40%. Physician characterization of the visit increased explained variance to 57%. The average revisit interval adjusted for patient characteristics for each of the 11 physicians varied from 4 to 20 weeks. Although all physicians lengthened revisit intervals for routine visits and shortened them when changing management, the relative ranking of mean revisit intervals for each physician changed little for different visit characterizations—some physicians were consistently long and others were consistently short. CONCLUSION Physicians vary widely in their recommendations for office revisits. Patient factors accounted for only a small part of this variation. Although physicians responded to visits in predictable ways, each physician appeared to have a unique set point for the length of the revisits interval. PMID:10203635

Concurrent chemoradiotherapy with S-1 in patients with stage III-IV oral squamous cell carcinoma: A retrospective analysis of nodal classification based on the neck node level.

PubMed

Murakami, Ryuji; Semba, Akiko; Kawahara, Kenta; Matsuyama, Keiya; Hiraki, Akimitsu; Nagata, Masashi; Toya, Ryo; Yamashita, Yasuyuki; Oya, Natsuo; Nakayama, Hideki

2017-07-01

The aim of the present study was to retrospectively evaluate the treatment outcomes of concurrent chemoradiotherapy (CCRT) with S-1, an oral fluoropyrimidine anticancer agent, for advanced oral squamous cell carcinoma (SCC). The study population consisted of 47 patients with clinical stage III or IV oral SCC, who underwent CCRT with S-1. Pretreatment variables, including patient age, clinical stage, T classification, midline involvement of the primary tumor and nodal status, were analyzed as predictors of survival. In addition to the N classification (node-positive, multiple and contralateral), the prognostic impact of the level of nodal involvement was assessed. Nodal involvement was mainly observed at levels Ib and II; involvement at levels Ia and III-V was considered to be anterior and inferior extension, respectively, and was recorded as extensive nodal involvement (ENI). The 3-year overall survival (OS) and progression-free survival (PFS) rates were 37 and 27%, respectively. A finding of ENI was a significant factor for OS [hazard ratio (HR)=2.16; 95% confidence interval (CI): 1.03-4.55; P=0.038] and PFS (HR=2.65; 95% CI: 1.32-5.33; P=0.005); the 3-year OS and PFS rates in patients with vs. those without ENI were 23 vs. 50% and 9 vs. 43%, respectively. The other variables were not significant. Therefore, CCRT with S-1 may be an alternative treatment for advanced oral SCC; favorable outcomes are expected in patients without ENI.

Concurrent information affects response inhibition processes via the modulation of theta oscillations in cognitive control networks.

PubMed

Chmielewski, Witold X; Mückschel, Moritz; Dippel, Gabriel; Beste, Christian

2016-11-01

Inhibiting responses is a challenge, where the outcome (partly) depends on the situational context. In everyday situations, response inhibition performance might be altered when irrelevant input is presented simultaneously with the information relevant for response inhibition. More specifically, irrelevant concurrent information may either brace or interfere with response-relevant information, depending on whether these inputs are redundant or conflicting. The aim of this study is to investigate neurophysiological mechanisms and the network underlying such modulations using EEG beamforming as method. The results show that in comparison to a baseline condition without concurrent information, response inhibition performance can be aggravated or facilitated by manipulating the extent of conflict via concurrent input. This depends on whether the requirement for cognitive control is high, as in conflicting trials, or whether it is low, as in redundant trials. In line with this, the total theta frequency power decreases in a right hemispheric orbitofrontal response inhibition network including the SFG, MFG, and SMA, when concurrent redundant information facilitates response inhibition processes. Vice versa, theta activity in a left-hemispheric response inhibition network (i.e., SFG, MFG, and IFG) increases, when conflicting concurrent information compromises response inhibition processes. We conclude that concurrent information bi-directionally shifts response inhibition performance and modulates the network architecture underlying theta oscillations which are signaling different levels of the need for cognitive control.

Are preference and resistance to change convergent expressions of stimulus value?

PubMed

Podlesnik, Christopher A; Jimenez-Gomez, Corina; Shahan, Timothy A

2013-07-01

Behavioral momentum theory asserts that preference and relative resistance to disruption depend on reinforcement rates and provide converging expressions of the conditioned value of discriminative stimuli. However, preference and resistance to disruption diverge when assessing preference during brief extinction probes. We expanded upon this opposing relation by arranging target stimuli signaling equal variable-interval schedules across components of a multiple schedule. We paired one target stimulus with a richer reinforced alternative and the other with a leaner alternative. Furthermore, we varied reinforcement rates for the paired alternatives to assess the effects of manipulating relative conditioned value on preference and resistance to disruption by presession feeding, intercomponent food, and extinction. We replicated the opposing relation between preference and resistance to disruption but varying reinforcement rates for the paired alternatives did not systematically affect preference or resistance to disruption beyond levels observed in our initial condition. Importantly, we found that only preference between the target stimuli was related to relative baseline response rates in the presence of those stimuli. These findings suggest that preference during extinction probes might reveal more about baseline response rates between concurrently available alternatives than relative conditioned value. Resistance to disruption, conversely, appears to better reflect conditioned value because it is less confounded with baseline response rates and is a function of all sources of reinforcement obtained in the presence of a stimulus context. © Society for the Experimental Analysis of Behavior.

Interresponse Time Structures in Variable-Ratio and Variable-Interval Schedules

ERIC Educational Resources Information Center

Bowers, Matthew T.; Hill, Jade; Palya, William L.

2008-01-01

The interresponse-time structures of pigeon key pecking were examined under variable-ratio, variable-interval, and variable-interval plus linear feedback schedules. Whereas the variable-ratio and variable-interval plus linear feedback schedules generally resulted in a distinct group of short interresponse times and a broad distribution of longer…

Secondary task for full flight simulation incorporating tasks that commonly cause pilot error: Time estimation

NASA Technical Reports Server (NTRS)

Rosch, E.

1975-01-01

The task of time estimation, an activity occasionally performed by pilots during actual flight, was investigated with the objective of providing human factors investigators with an unobtrusive and minimally loading additional task that is sensitive to differences in flying conditions and flight instrumentation associated with the main task of piloting an aircraft simulator. Previous research indicated that the duration and consistency of time estimates is associated with the cognitive, perceptual, and motor loads imposed by concurrent simple tasks. The relationships between the length and variability of time estimates and concurrent task variables under a more complex situation involving simulated flight were clarified. The wrap-around effect with respect to baseline duration, a consequence of mode switching at intermediate levels of concurrent task distraction, should contribute substantially to estimate variability and have a complex effect on the shape of the resulting distribution of estimates.

Hematologic and serum biochemical reference intervals for free-ranging common bottlenose dolphins (Tursiops truncatus) and variation in the distributions of clinicopathologic values related to geographic sampling site.

PubMed

Schwacke, Lori H; Hall, Ailsa J; Townsend, Forrest I; Wells, Randall S; Hansen, Larry J; Hohn, Aleta A; Bossart, Gregory D; Fair, Patricia A; Rowles, Teresa K

2009-08-01

To develop robust reference intervals for hematologic and serum biochemical variables by use of data derived from free-ranging bottlenose dolphins (Tursiops truncatus) and examine potential variation in distributions of clinicopathologic values related to sampling sites' geographic locations. 255 free-ranging bottlenose dolphins. Data from samples collected during multiple bottlenose dolphin capture-release projects conducted at 4 southeastern US coastal locations in 2000 through 2006 were combined to determine reference intervals for 52 clinicopathologic variables. A nonparametric bootstrap approach was applied to estimate 95th percentiles and associated 90% confidence intervals; the need for partitioning by length and sex classes was determined by testing for differences in estimated thresholds with a bootstrap method. When appropriate, quantile regression was used to determine continuous functions for 95th percentiles dependent on length. The proportion of out-of-range samples for all clinicopathologic measurements was examined for each geographic site, and multivariate ANOVA was applied to further explore variation in leukocyte subgroups. A need for partitioning by length and sex classes was indicated for many clinicopathologic variables. For each geographic site, few significant deviations from expected number of out-of-range samples were detected. Although mean leukocyte counts did not vary among sites, differences in the mean counts for leukocyte subgroups were identified. Although differences in the centrality of distributions for some variables were detected, the 95th percentiles estimated from the pooled data were robust and applicable across geographic sites. The derived reference intervals provide critical information for conducting bottlenose dolphin population health studies.

CHANGING ATTITUDES ABOUT CONCURRENCY AMONG YOUNG AFRICAN AMERICANS: RESULTS OF A RADIO CAMPAIGN

PubMed Central

Adimora, Adaora A.; Schoenbach, Victor J.; Cates, Joan R.; Cope, Anna B.; Ramirez, Catalina; Powell, Wizdom; Agans, Robert P.

2018-01-01

We created and evaluated an 8-month campaign of provocative radio ads to change attitudes about concurrent (overlapping) sexual partnerships among young African Americans. Using focus groups, vignette-based items, and factor analysis, we created a concurrency attitude scale and compared its score distributions in independent samples of African Americans, ages 18-34 years, interviewed by telephone before (n=678) and after (n=479) the campaign. Pre-and post-campaign samples reflected similar response rates (pre: 32.6%; post: 31.8%) and distributions of personal characteristics. Reported exposure to concurrency messages was greater after the campaign (pre: 6.3%, post: 30.9%), and mean scores became less accepting of concurrency (pre: 3.40 (95% confidence interval: 3.23, 3.57); post: 2.62 (2.46, 2.78)). Score differences were not a function of differences in composition of the two samples (adjusted means: pre: 3.37 (3.21, 3.53); post: 2.62 (2.47, 2.76)). Findings demonstrate that a carefully targeted, intensive mass media campaign can change attitudes about concurrency, which should facilitate behavior change. PMID:28825864

Clarifying the Relationship between Impulsive Delay Discounting and Nicotine Dependence

PubMed Central

Amlung, Michael; MacKillop, James

2014-01-01

Impulsive delayed reward discounting (DRD) has been linked to nicotine dependence, but with some inconsistency. This may be related to the considerable variability in the literature with regard to the DRD assessments used, particularly in the case of reward magnitudes assessed. In addition, previous studies have often not considered concurrent substance use when examining the relationship between DRD and nicotine dependence. The current study sought to further clarify the relationship between DRD and nicotine dependence by characterizing DRD across diverse reward magnitudes and incorporating other substance use. Daily smokers (N = 933) were assessed for DRD preferences across nine reward magnitudes (delayed reward range: $2.50–$850), comorbid substance use, and relevant demographic variables (age, education, income). A significant large effect size magnitude effect was found for DRD, reflecting steeper discounting for smaller delayed rewards, but significant correlations across magnitudes also suggested similar relative levels of discounting. Principal components analysis (PCA) was used to generate a single latent index of discounting across all magnitudes that accounted for 67% of the total variance. In both correlation and regression analyses, steeper composite DRD was significantly associated with nicotine dependence severity. This relationship remained statistically significant after incorporating demographic variables and alcohol and illicit drug use. These findings provide evidence of a specific link between impulsive DRD and nicotine dependence, and reveal that this association is robust across a broad range of monetary rewards. The study also demonstrates the utility of using PCA to generate latent indices of delay discounting across multiple magnitudes of delayed reward. PMID:24841186

Low thermal dependence of the contractile properties of a wing muscle in the bat Carollia perspicillata.

PubMed

Rummel, Andrea D; Swartz, Sharon M; Marsh, Richard L

2018-05-29

Temperature affects contractile rate properties in muscle, which may affect locomotor performance. Endotherms are known to maintain high core body temperatures, but temperatures in the periphery of the body can fluctuate. Such a phenomenon occurs in bats, whose wing musculature is relatively poorly insulated, resulting in substantially depressed temperatures in the distal wing. We examined a wing muscle in the small-bodied tropical bat Carollia perspicillata and a hindlimb muscle in the laboratory mouse at 5°C intervals from 22 to 42°C to determine the thermal dependence of the contractile properties of both muscles. We found that the bat ECRL had low thermal dependence from near body temperature to 10°C lower, with Q 10 values of less than 1.5 for relaxation from contraction and shortening velocities in that interval, and with no significant difference in some rate properties in the interval between 32 and 37°C. In contrast, for all temperature intervals below 37°C, Q 10 values for the mouse EDL were 1.5 or higher, and rate properties differed significantly across successive temperature intervals from 37 to 22°C. An ANCOVA analysis found that the thermal dependencies of all measured isometric and isotonic rate processes were significantly different between the bat and mouse muscles. The relatively low thermal dependence of the bat muscle likely represents a downward shift of its optimal temperature and may be functionally significant in light of the variable operating temperatures of bat wing muscles. © 2018. Published by The Company of Biologists Ltd.

Response-reinforcer dependency and resistance to change.

PubMed

Cançado, Carlos R X; Abreu-Rodrigues, Josele; Aló, Raquel Moreira; Hauck, Flávia; Doughty, Adam H

2018-01-01

The effects of the response-reinforcer dependency on resistance to change were studied in three experiments with rats. In Experiment 1, lever pressing produced reinforcers at similar rates after variable interreinforcer intervals in each component of a two-component multiple schedule. Across conditions, in the fixed component, all reinforcers were response-dependent; in the alternative component, the percentage of response-dependent reinforcers was 100, 50 (i.e., 50% response-dependent and 50% response-independent) or 10% (i.e., 10% response-dependent and 90% response-independent). Resistance to extinction was greater in the alternative than in the fixed component when the dependency in the former was 10%, but was similar between components when this dependency was 100 or 50%. In Experiment 2, a three-component multiple schedule was used. The dependency was 100% in one component and 10% in the other two. The 10% components differed on how reinforcers were programmed. In one component, as in Experiment 1, a reinforcer had to be collected before the scheduling of other response-dependent or independent reinforcers. In the other component, response-dependent and -independent reinforcers were programmed by superimposing a variable-time schedule on an independent variable-interval schedule. Regardless of the procedure used to program the dependency, resistance to extinction was greater in the 10% components than in the 100% component. These results were replicated in Experiment 3 in which, instead of extinction, VT schedules replaced the baseline schedules in each multiple-schedule component during the test. We argue that the relative change in dependency from Baseline to Test, which is greater when baseline dependencies are high rather than low, could account for the differential resistance to change in the present experiments. The inconsistencies in results across the present and previous experiments suggest that the effects of dependency on resistance to change are not well understood. Additional systematic analyses are important to further understand the effects of the response-reinforcer relation on resistance to change and to the development of a more comprehensive theory of behavioral persistence. © 2017 Society for the Experimental Analysis of Behavior.

Effect of concurrent training on gender-specific biochemical variables and adiposity in obese adolescents.

PubMed

Antunes, Barbara de Moura Mello; Christofaro, Diego Giuliano Destro; Monteiro, Paula Alves; Silveira, Loreana Sanches; Fernandes, Rômulo Araújo; Mota, Jorge; Freitas Júnior, Ismael Forte

2015-08-01

The purpose of the present study was to analyze the effects of a 20-week concurrent training (20 WCT) intervention program on gender-specific body composition and metabolic variables in obese adolescents. Sample was composed of twenty-five obese adolescents, aged between 12 and 15 (13.4 ± 0.96) years. Fat-free mass (FFM), percentage trunk fat mass (TFM%) and percentage fat mass (%FM) were evaluated through dual-energy X-ray absorptiometry (DXA). Measurement of intra-abdominal adiposity (IAAT) was performed using ultrasound. Blood pressure was measured and blood samples analyzed for total cholesterol (TC), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), triglycerides (TG) and plasma glucose. All participants performed the concurrent training (combination of weight training and aerobic training) three times per week, one hour per day, for 20 weeks. Descriptive analysis and analysis of variance (ANOVA) for repeated measures were used to compare baseline, 10 week and 20 week moments using the Bonferroni post-hoc test. Statistical significance was set at p < 0.05. Significant decrease in TC, LDL-c and TFM% were verified in both genders after the 10 initial weeks of concurrent training. A significant increase in height was found in both the male and female groups (p = 0.001 and p = 0.047, respectively), after 20 weeks of concurrent training. In addition, several modifications were observed in body composition and metabolic variables, with a significant decrease in BMI (p = 0.002 and p = 0.017), BMI z-score (p = 0.033 and p = 0.004), FM% (p = 0.002 and p = 0.002), TFM% (p = 0.009 and p = 0.018), TC (p = 0.042 and p = 0.001) and LDL-c (p = 0.006 and p = 0.001) in the male and female groups, respectively, after 20 weeks of intervention when compared with baseline. Our results identified that concurrent training was an effective intervention for treating metabolic variable and body composition disorders, in both genders, by decreasing adiposity with consequent improvement in BMI and BMI z-scores, and enhancement in lipid profile variables.

Concurrent criterion validity of the safe driving behavior measure: a predictor of on-road driving outcomes.

PubMed

Classen, Sherrilene; Wang, Yanning; Winter, Sandra M; Velozo, Craig A; Lanford, Desiree N; Bédard, Michel

2013-01-01

We determined the concurrent criterion validity of the Safe Driving Behavior Measure (SDBM) for on-road outcomes (passing or failing the on-road test as determined by a certified driving rehabilitation specialist) among older drivers and their family members-caregivers. On the basis of ratings from 168 older drivers and 168 family members-caregivers, we calculated receiver operating characteristic curves. The drivers' area under the curve (AUC) was .620 (95% confidence interval [CI] = .514-.725, p = .043). The family members-caregivers' AUC was .726 (95% CI = .622-.829, p ≤ .01). Older drivers' ratings showed statistically significant yet poor concurrent criterion validity, but family members-caregivers' ratings showed good concurrent criterion validity for the criterion on-road driving test. Continuing research with a more representative sample is being pursued to confirm the SDBM's concurrent criterion validity. This screening tool may be useful for generalist practitioners to use in making decisions regarding driving. Copyright © 2013 by the American Occupational Therapy Association, Inc.

Concurrent Criterion Validity of the Safe Driving Behavior Measure: A Predictor of On-Road Driving Outcomes

PubMed Central

Wang, Yanning; Winter, Sandra M.; Velozo, Craig A.; Lanford, Desiree N.; Bédard, Michel

2013-01-01

We determined the concurrent criterion validity of the Safe Driving Behavior Measure (SDBM) for on-road outcomes (passing or failing the on-road test as determined by a certified driving rehabilitation specialist) among older drivers and their family members–caregivers. On the basis of ratings from 168 older drivers and 168 family members–caregivers, we calculated receiver operating characteristic curves. The drivers’ area under the curve (AUC) was .620 (95% confidence interval [CI] = .514–.725, p = .043). The family members–caregivers’ AUC was .726 (95% CI = .622–.829, p ≤ .01). Older drivers’ ratings showed statistically significant yet poor concurrent criterion validity, but family members–caregivers’ ratings showed good concurrent criterion validity for the criterion on-road driving test. Continuing research with a more representative sample is being pursued to confirm the SDBM’s concurrent criterion validity. This screening tool may be useful for generalist practitioners to use in making decisions regarding driving. PMID:23245789

Discrete physiological effects of beetroot juice and potassium nitrate supplementation following 4-wk sprint interval training.

PubMed

Thompson, Christopher; Vanhatalo, Anni; Kadach, Stefan; Wylie, Lee J; Fulford, Jonathan; Ferguson, Scott K; Blackwell, Jamie R; Bailey, Stephen J; Jones, Andrew M

2018-06-01

The physiological and exercise performance adaptations to sprint interval training (SIT) may be modified by dietary nitrate ([Formula: see text]) supplementation. However, it is possible that different types of [Formula: see text] supplementation evoke divergent physiological and performance adaptations to SIT. The purpose of this study was to compare the effects of 4-wk SIT with and without concurrent dietary [Formula: see text] supplementation administered as either [Formula: see text]-rich beetroot juice (BR) or potassium [Formula: see text] (KNO 3 ). Thirty recreationally active subjects completed a battery of exercise tests before and after a 4-wk intervention in which they were allocated to one of three groups: 1) SIT undertaken without dietary [Formula: see text] supplementation (SIT); 2) SIT accompanied by concurrent BR supplementation (SIT + BR); or 3) SIT accompanied by concurrent KNO 3 supplementation (SIT + KNO 3 ). During severe-intensity exercise, V̇o 2peak and time to task failure were improved to a greater extent with SIT + BR than SIT and SIT + KNO 3 ( P < 0.05). There was also a greater reduction in the accumulation of muscle lactate at 3 min of severe-intensity exercise in SIT + BR compared with SIT + KNO 3 ( P < 0.05). Plasma [Formula: see text] concentration fell to a greater extent during severe-intensity exercise in SIT + BR compared with SIT and SIT + KNO 3 ( P < 0.05). There were no differences between groups in the reduction in the muscle phosphocreatine recovery time constant from pre- to postintervention ( P > 0.05). These findings indicate that 4-wk SIT with concurrent BR supplementation results in greater exercise capacity adaptations compared with SIT alone and SIT with concurrent KNO 3 supplementation. This may be the result of greater NO-mediated signaling in SIT + BR compared with SIT + KNO 3 . NEW & NOTEWORTHY We compared the influence of different forms of dietary nitrate supplementation on the physiological and performance adaptations to sprint interval training (SIT). Compared with SIT alone, supplementation with nitrate-rich beetroot juice, but not potassium [Formula: see text], enhanced some physiological adaptations to training.

An Adaptive Flow Solver for Air-Borne Vehicles Undergoing Time-Dependent Motions/Deformations

NASA Technical Reports Server (NTRS)

Singh, Jatinder; Taylor, Stephen

1997-01-01

This report describes a concurrent Euler flow solver for flows around complex 3-D bodies. The solver is based on a cell-centered finite volume methodology on 3-D unstructured tetrahedral grids. In this algorithm, spatial discretization for the inviscid convective term is accomplished using an upwind scheme. A localized reconstruction is done for flow variables which is second order accurate. Evolution in time is accomplished using an explicit three-stage Runge-Kutta method which has second order temporal accuracy. This is adapted for concurrent execution using another proven methodology based on concurrent graph abstraction. This solver operates on heterogeneous network architectures. These architectures may include a broad variety of UNIX workstations and PCs running Windows NT, symmetric multiprocessors and distributed-memory multi-computers. The unstructured grid is generated using commercial grid generation tools. The grid is automatically partitioned using a concurrent algorithm based on heat diffusion. This results in memory requirements that are inversely proportional to the number of processors. The solver uses automatic granularity control and resource management techniques both to balance load and communication requirements, and deal with differing memory constraints. These ideas are again based on heat diffusion. Results are subsequently combined for visualization and analysis using commercial CFD tools. Flow simulation results are demonstrated for a constant section wing at subsonic, transonic, and a supersonic case. These results are compared with experimental data and numerical results of other researchers. Performance results are under way for a variety of network topologies.

Travel time and concurrent-schedule choice: retrospective versus prospective control.

PubMed

Davison, M; Elliffe, D

2000-01-01

Six pigeons were trained on concurrent variable-interval schedules in which two different travel times between alternatives, 4.5 and 0.5 s, were randomly arranged. In Part 1, the next travel time was signaled while the subjects were responding on each alternative. Generalized matching analyses of performance in the presence of the two travel-time signals showed significantly higher response and time sensitivity when the longer travel time was signaled compared to when the shorter time was signaled. When the data were analyzed as a function of the previous travel time, there were no differences in sensitivity. Dwell times on the alternatives were consistently longer in the presence of the stimulus that signaled the longer travel time than they were in the presence of the stimulus that signaled the shorter travel time. These results are in accord with a recent quantitative account of the effects of travel time. In Part 2, no signals indicating the next travel time were given. When these data were analyzed as a function of the previous travel time, time-allocation sensitivity after the 4.5-s travel time was significantly greater than that after the 0.5-s travel time, but no such difference was found for response allocation. Dwell times were also longer when the previous travel time had been longer.

Concurrent deployment of visual attention and response selection bottleneck in a dual-task: Electrophysiological and behavioural evidence.

PubMed

Reimer, Christina B; Strobach, Tilo; Schubert, Torsten

2017-12-01

Visual attention and response selection are limited in capacity. Here, we investigated whether visual attention requires the same bottleneck mechanism as response selection in a dual-task of the psychological refractory period (PRP) paradigm. The dual-task consisted of an auditory two-choice discrimination Task 1 and a conjunction search Task 2, which were presented at variable temporal intervals (stimulus onset asynchrony, SOA). In conjunction search, visual attention is required to select items and to bind their features resulting in a serial search process around the items in the search display (i.e., set size). We measured the reaction time of the visual search task (RT2) and the N2pc, an event-related potential (ERP), which reflects lateralized visual attention processes. If the response selection processes in Task 1 influence the visual attention processes in Task 2, N2pc latency and amplitude would be delayed and attenuated at short SOA compared to long SOA. The results, however, showed that latency and amplitude were independent of SOA, indicating that visual attention was concurrently deployed to response selection. Moreover, the RT2 analysis revealed an underadditive interaction of SOA and set size. We concluded that visual attention does not require the same bottleneck mechanism as response selection in dual-tasks.

Mechanisms of impulsive choice: III. The role of reward processes

PubMed Central

Marshall, Andrew T.

2015-01-01

Two experiments examined the relationship between reward processing and impulsive choice. In Experiment 1, rats chose between a smaller-sooner (SS) reward (1 pellet, 10 s) and a larger-later (LL) reward (1, 2, and 4 pellets, 30 s). The rats then experienced concurrent variable-interval 30-s schedules with variations in reward magnitude to evaluate reward magnitude discrimination. LL choice behavior positively correlated with reward magnitude discrimination. In Experiment 2, rats chose between an SS reward (1 pellet, 10 s) and an LL reward (2 and 4 pellets, 30 s). The rats then received either a reward intervention which consisted of concurrent fixed-ratio schedules associated with different magnitudes to improve their reward magnitude discrimination, or a control task. All rats then experienced a post-intervention impulsive choice task followed by a reward magnitude discrimination task to assess intervention efficacy. The rats that received the intervention exhibited increases in post-intervention LL choice behavior, and made more responses for larger-reward magnitudes in the reward magnitude discrimination task, suggesting that the intervention heightened sensitivities to reward magnitude. The results suggest that reward magnitude discrimination plays a key role in individual differences in impulsive choice, and could be a potential target for further intervention developments. PMID:26506254

Free Interval Duration: Clinical Evidence of the Primary Role of Excitement in Bipolar Disorder.

PubMed

Sani, Gabriele; Simonetti, Alessio; Reginaldi, Daniela; Koukopoulos, Alexia E; Del Casale, Antonio; Manfredi, Giovanni; Kotzalidis, Georgios D; Girardi, Paolo

2017-04-01

Cyclicity is the essential feature of Bipolar disorder, but the effect of different cycle patterns on the clinical features is poorly understood. Moreover, no studies investigated the relationship between mania and depression inside the manic-depressive cycle. The aim of this study is to verify the presence of a relationship between the manic and the depressive phase during the course of bipolar disorder. 160 consecutive patients with BD type I were recruited and followed for a mean period of 10 years. During the follow-up period, four types of euthymic phases were collected: free intervals present between a depressive and a manic/hypomanic episode (D-M); free intervals present between a manic/hypomanic and a depressive episode (M-D); free intervals present between two depressive episodes (D-D); free intervals present between two manic/hypomanic episodes (M-M). One-way ANOVA using the groups as independent variable and the duration of the free intervals as dependent variables was used. Furthermore, ANOVA was followed by Fisher's Protected Least Significant Difference post-hoc test to measure between-group differences. M-D-free interval phases were shorter than D-M-free intervals. M-D intervals were the shortest ones, the D-D and D-M did not differ, and the M-M were the longest. The strict temporal link between manic and depressive phases supports the idea that the manic-depressive cycle usually begins with a manic episode, and that the subsequent depression is often the consequence of subsiding mania.

Ruminative Self-Focus and Negative Affect

PubMed Central

Moberly, Nicholas J.; Watkins, Edward R.

2008-01-01

The authors conducted an experience sampling study to investigate the relationship between momentary ruminative self-focus and negative affect. Ninety-three adults recorded these variables at quasi-random intervals 8 times daily for 1 week. Scores on questionnaire measures of dispositional rumination were associated with mean levels of momentary ruminative self-focus over the experience sampling week. Concurrently, momentary ruminative self-focus was positively associated with negative affect. Cross-lagged analyses revealed that whereas ruminative self-focus predicted negative affect at a subsequent occasion, negative affect also predicted ruminative self-focus at a subsequent occasion. Decomposition of the dispositional rumination measure suggested that brooding, but not reflective pondering, was associated with higher mean levels of negative affect. Though broadly consistent with Nolen-Hoeksema's (1991) response styles theory, these results suggest that a reciprocal relationship exists between ruminative self-focus and negative affect. PMID:18489207

Evapotranspiration and runoff from large land areas: Land surface hydrology for atmospheric general circulation models

NASA Technical Reports Server (NTRS)

Famiglietti, J. S.; Wood, Eric F.

1993-01-01

A land surface hydrology parameterization for use in atmospheric GCM's is presented. The parameterization incorporates subgrid scale variability in topography, soils, soil moisture and precipitation. The framework of the model is the statistical distribution of a topography-soils index, which controls the local water balance fluxes, and is therefore taken to represent the large land area. Spatially variable water balance fluxes are integrated with respect to the topography-soils index to yield our large topography-soils distribution, and interval responses are weighted by the probability of occurrence of the interval. Grid square averaged land surface fluxes result. The model functions independently as a macroscale water balance model. Runoff ratio and evapotranspiration efficiency parameterizations are derived and are shown to depend on the spatial variability of the above mentioned properties and processes, as well as the dynamics of land surface-atmosphere interactions.

Bi-Level Integrated System Synthesis (BLISS)

NASA Technical Reports Server (NTRS)

Sobieszczanski-Sobieski, Jaroslaw; Agte, Jeremy S.; Sandusky, Robert R., Jr.

1998-01-01

BLISS is a method for optimization of engineering systems by decomposition. It separates the system level optimization, having a relatively small number of design variables, from the potentially numerous subsystem optimizations that may each have a large number of local design variables. The subsystem optimizations are autonomous and may be conducted concurrently. Subsystem and system optimizations alternate, linked by sensitivity data, producing a design improvement in each iteration. Starting from a best guess initial design, the method improves that design in iterative cycles, each cycle comprised of two steps. In step one, the system level variables are frozen and the improvement is achieved by separate, concurrent, and autonomous optimizations in the local variable subdomains. In step two, further improvement is sought in the space of the system level variables. Optimum sensitivity data link the second step to the first. The method prototype was implemented using MATLAB and iSIGHT programming software and tested on a simplified, conceptual level supersonic business jet design, and a detailed design of an electronic device. Satisfactory convergence and favorable agreement with the benchmark results were observed. Modularity of the method is intended to fit the human organization and map well on the computing technology of concurrent processing.

Modelling the adverse effects associated with ecstasy use.

PubMed

Fisk, John E; Murphy, Philip N; Montgomery, Catharine; Hadjiefthyvoulou, Florentia

2011-04-01

Ecstasy, the street name for 3,4-meththylenedioxymethamphetamine, has been associated with a range of psychiatric symptoms and impaired psychological health in both problem and recreational users. The purpose of the present paper is to determine how these impairments are related to the history of polydrug use, and the conditions under which individuals ingest ecstasy. Associations between the variables of interest were investigated utilizing negative binomial regression. Liverpool and Preston in the North West of England. A convenience sample of 159 recreational ecstasy/polydrug users (80 males, 79 females). The sample was composed primarily of undergraduates. The dependent variable was the number of reported ecstasy-related adverse effects. Independent variables included quantitative aspects of ecstasy and other drug use, and the various beliefs and behaviours associated with ecstasy use. The number of adverse effects was associated positively with life-time exposure to ecstasy and negatively with period of abstinence from the drug. Adverse effects were more common among those who consumed ecstasy and alcohol concurrently, but were unrelated to other aspects of polydrug use. They were unaffected by whether the user took precautions when using the drug, and only weakly related to prior beliefs concerning the effects of ecstasy. Greater life-time exposure to ecstasy and consuming the drug concurrently with alcohol increase the likelihood of experiencing adverse effects, including paranoia, poor general health, irritability, confusion and moodiness. Adverse effects decrease with the period of abstinence from the drug. © 2010 The Authors, Addiction © 2010 Society for the Study of Addiction.

Efficiently sampling conformations and pathways using the concurrent adaptive sampling (CAS) algorithm

NASA Astrophysics Data System (ADS)

Ahn, Surl-Hee; Grate, Jay W.; Darve, Eric F.

2017-08-01

Molecular dynamics simulations are useful in obtaining thermodynamic and kinetic properties of bio-molecules, but they are limited by the time scale barrier. That is, we may not obtain properties' efficiently because we need to run microseconds or longer simulations using femtosecond time steps. To overcome this time scale barrier, we can use the weighted ensemble (WE) method, a powerful enhanced sampling method that efficiently samples thermodynamic and kinetic properties. However, the WE method requires an appropriate partitioning of phase space into discrete macrostates, which can be problematic when we have a high-dimensional collective space or when little is known a priori about the molecular system. Hence, we developed a new WE-based method, called the "Concurrent Adaptive Sampling (CAS) algorithm," to tackle these issues. The CAS algorithm is not constrained to use only one or two collective variables, unlike most reaction coordinate-dependent methods. Instead, it can use a large number of collective variables and adaptive macrostates to enhance the sampling in the high-dimensional space. This is especially useful for systems in which we do not know what the right reaction coordinates are, in which case we can use many collective variables to sample conformations and pathways. In addition, a clustering technique based on the committor function is used to accelerate sampling the slowest process in the molecular system. In this paper, we introduce the new method and show results from two-dimensional models and bio-molecules, specifically penta-alanine and a triazine trimer.

Concurrent Validity of a Portable Force Plate Using Vertical Jump Force-Time Characteristics.

PubMed

Lake, Jason; Mundy, Peter; Comfort, Paul; McMahon, John J; Suchomel, Timothy J; Carden, Patrick

2018-05-29

This study examined concurrent validity of countermovement vertical jump (CMJ) reactive strength index modified and force-time characteristics recorded using a one dimensional portable and laboratory force plate system. Twenty-eight men performed bilateral CMJs on two portable force plates placed on top of two in-ground force plates, both recording vertical ground reaction force at 1000 Hz. Time to take-off, jump height, reactive strength index modified, braking and propulsion impulse, mean net force, and duration were calculated from the vertical force from both force plate systems. Results from both systems were highly correlated (r≥.99). There were small (d<.12) but significant differences between their respective braking impulse, braking mean net force, propulsion impulse, and propulsion mean net force (p<.001). However, limits of agreement yielded a mean value of 1.7% relative to the laboratory force plate system (95% CL: .9% to 2.5%), indicating very good agreement across all of the dependent variables. The largest limits of agreement belonged to jump height (2.1%), time to take-off (3.4%), and reactive strength index modified (3.8%). The portable force plate system provides a valid method of obtaining reactive strength measures, and several underpinning force-time variables, from unloaded CMJ and practitioners can use both force plates interchangeably.

Maximum predictive power and the superposition principle

NASA Technical Reports Server (NTRS)

Summhammer, Johann

1994-01-01

In quantum physics the direct observables are probabilities of events. We ask how observed probabilities must be combined to achieve what we call maximum predictive power. According to this concept the accuracy of a prediction must only depend on the number of runs whose data serve as input for the prediction. We transform each probability to an associated variable whose uncertainty interval depends only on the amount of data and strictly decreases with it. We find that for a probability which is a function of two other probabilities maximum predictive power is achieved when linearly summing their associated variables and transforming back to a probability. This recovers the quantum mechanical superposition principle.

Concurrent cannabis use during treatment for comorbid ADHD and cocaine dependence: effects on outcome.

PubMed

Aharonovich, Efrat; Garawi, Fatima; Bisaga, Adam; Brooks, Daniel; Raby, Wilfrid N; Rubin, Eric; Nunes, Edward V; Levin, Frances R

2006-01-01

Cannabis is the most widely used illicit substance in the United States with especially high prevalence of use among those with psychiatric disorders. Few studies have examined the relationship between concurrent cannabis use and treatment outcome among patients receiving treatment for comorbid substance abuse and psychiatric disorders. This study investigated the effects of cannabis use on treatment retention and abstinence from cocaine among cocaine dependent patients with Attention Deficit Hyperactivity Disorder (ADHD). Cocaine dependent patients diagnosed with current ADHD (DSM-IV, N = 92) aged 25 to 51 participated in a randomized clinical trial of methylphenidate for treatment of ADHD and cocaine dependence in an outpatient setting. The majority of patients (69%) used cannabis during treatment. Results suggest that moderate/intermittent cannabis users had greater retention rates compared to abstainers and consistent users (p = .02). This study is the first to examine concurrent cannabis use in cocaine dependent patients diagnosed with ADHD.

Effects of endurance, resistance, and concurrent exercise on learning and memory after morphine withdrawal in rats.

PubMed

Zarrinkalam, Ebrahim; Heidarianpour, Ali; Salehi, Iraj; Ranjbar, Kamal; Komaki, Alireza

2016-07-15

Continuous morphine consumption contributes to the development of cognitive disorders. This work investigates the impacts of different types of exercise on learning and memory in morphine-dependent rats. Forty morphine-dependent rats were randomly divided into five groups: sedentary-dependent (Sed-D), endurance exercise-dependent (En-D), strength exercise-dependent (St-D), and combined (concurrent) exercise-dependent (Co-D). Healthy rats were used as controls (Con). After 10weeks of regular exercise (endurance, strength, and concurrent; each five days per week), spatial and aversive learning and memory were assessed using the Morris water maze and shuttle box tests. The results showed that morphine addiction contributes to deficits in spatial learning and memory. Furthermore, each form of exercise training restored spatial learning and memory performance in morphine-dependent rats to levels similar to those of healthy controls. Aversive learning and memory during the acquisition phase were not affected by morphine addiction or exercise, but were significantly decreased by morphine dependence. Only concurrent training returned the time spent in the dark compartment in the shuttle box test to control levels. These findings show that different types of exercise exert similar effects on spatial learning and memory, but show distinct effects on aversive learning and memory. Further, morphine dependence-induced deficits in cognitive function were blocked by exercise. Therefore, different exercise regimens may represent practical treatment methods for cognitive and behavioral impairments associated with morphine-related disease. Copyright © 2016 Elsevier Inc. All rights reserved.

[Renal hemodynamic in hydronephrosis concurrent with hepatobiliary system disorders, its dynamics in the course of treatment].

PubMed

Mambetov, Zh S; Salimov, B G

2016-02-01

This article examines measurements of renal vascular ultrasound in 85 patients with hydronephrosis concurrent with disorders of the gallbladder and biliary tract, depending on severity and dynamics during treatment. The estimation of blood flow changes depending on applied renoprotective and hepatoprotective therapy is provided.

Recent progresses in outcome-dependent sampling with failure time data.

PubMed

Ding, Jieli; Lu, Tsui-Shan; Cai, Jianwen; Zhou, Haibo

2017-01-01

An outcome-dependent sampling (ODS) design is a retrospective sampling scheme where one observes the primary exposure variables with a probability that depends on the observed value of the outcome variable. When the outcome of interest is failure time, the observed data are often censored. By allowing the selection of the supplemental samples depends on whether the event of interest happens or not and oversampling subjects from the most informative regions, ODS design for the time-to-event data can reduce the cost of the study and improve the efficiency. We review recent progresses and advances in research on ODS designs with failure time data. This includes researches on ODS related designs like case-cohort design, generalized case-cohort design, stratified case-cohort design, general failure-time ODS design, length-biased sampling design and interval sampling design.

Recent progresses in outcome-dependent sampling with failure time data

PubMed Central

Ding, Jieli; Lu, Tsui-Shan; Cai, Jianwen; Zhou, Haibo

2016-01-01

An outcome-dependent sampling (ODS) design is a retrospective sampling scheme where one observes the primary exposure variables with a probability that depends on the observed value of the outcome variable. When the outcome of interest is failure time, the observed data are often censored. By allowing the selection of the supplemental samples depends on whether the event of interest happens or not and oversampling subjects from the most informative regions, ODS design for the time-to-event data can reduce the cost of the study and improve the efficiency. We review recent progresses and advances in research on ODS designs with failure time data. This includes researches on ODS related designs like case–cohort design, generalized case–cohort design, stratified case–cohort design, general failure-time ODS design, length-biased sampling design and interval sampling design. PMID:26759313

Competitiveness as a moderator of the relation between appearance-related factors and disordered eating behaviors.

PubMed

Schleien, Jenna L; Bardone-Cone, Anna M

2016-06-01

The present study examined competitiveness as a moderator of the relationships between appearance-related factors (i.e., thin-ideal internalization, appearance contingent self-worth) and disordered eating behaviors (i.e., dieting, excessive exercise). Participants were 441 undergraduate females for cross-sectional analyses, with 237 also contributing data longitudinally, 1 year later. Results showed that, in a model including thin-ideal internalization and appearance contingent self-worth and their interactions with competitiveness, thin-ideal internalization (but not appearance contingent self-worth) interacted with competitiveness to identify concurrent levels of both dieting and excessive exercise. Individuals high in both thin-ideal internalization and competitiveness exhibited the highest levels of concurrent dieting and excessive exercise. After controlling for baseline levels of the dependent variables, neither appearance-related factor interacted with competitiveness to predict dieting or excessive exercise. These findings suggest that individuals who are both competitive and accept and strive to achieve the thin ideal may be at risk for disordered eating behaviors. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of music-based multitask training on gait, balance, and fall risk in elderly people: a randomized controlled trial.

PubMed

Trombetti, Andrea; Hars, Mélany; Herrmann, François R; Kressig, Reto W; Ferrari, Serge; Rizzoli, René

2011-03-28

Falls occur mainly while walking or performing concurrent tasks. We determined whether a music-based multitask exercise program improves gait and balance and reduces fall risk in elderly individuals. We conducted a 12-month randomized controlled trial involving 134 community-dwelling individuals older than 65 years, who are at increased risk of falling. They were randomly assigned to an intervention group (n = 66) or a delayed intervention control group scheduled to start the program 6 months later (n = 68). The intervention was a 6-month multitask exercise program performed to the rhythm of piano music. Change in gait variability under dual-task condition from baseline to 6 months was the primary end point. Secondary outcomes included changes in balance, functional performances, and fall risk. At 6 months, there was a reduction in stride length variability (adjusted mean difference, -1.4%; P < .002) under dual-task condition in the intervention group, compared with the delayed intervention control group. Balance and functional tests improved compared with the control group. There were fewer falls in the intervention group (incidence rate ratio, 0.46; 95% confidence interval, 0.27-0.79) and a lower risk of falling (relative risk, 0.61; 95% confidence interval, 0.39-0.96). Similar changes occurred in the delayed intervention control group during the second 6-month period with intervention. The benefit of the intervention on gait variability persisted 6 months later. In community-dwelling older people at increased risk of falling, a 6-month music-based multitask exercise program improved gait under dual-task condition, improved balance, and reduced both the rate of falls and the risk of falling. Trial Registration clinicaltrials.gov Identifier: NCT01107288.

Solar spectral irradiance variability in cycle 24: observations and models

NASA Astrophysics Data System (ADS)

Marchenko, Sergey V.; DeLand, Matthew T.; Lean, Judith L.

2016-12-01

Utilizing the excellent stability of the Ozone Monitoring Instrument (OMI), we characterize both short-term (solar rotation) and long-term (solar cycle) changes of the solar spectral irradiance (SSI) between 265 and 500 nm during the ongoing cycle 24. We supplement the OMI data with concurrent observations from the Global Ozone Monitoring Experiment-2 (GOME-2) and Solar Radiation and Climate Experiment (SORCE) instruments and find fair-to-excellent, depending on wavelength, agreement among the observations, and predictions of the Naval Research Laboratory Solar Spectral Irradiance (NRLSSI2) and Spectral And Total Irradiance REconstruction for the Satellite era (SATIRE-S) models.

Connecting Groundwater, Crop Price, and Crop Production Variability in India

NASA Astrophysics Data System (ADS)

Pollack, A.; Lobell, D. B.; Jain, M.

2015-12-01

Farmers in India rely on groundwater resources for irrigation and production of staple crops that provide over half of the calories consumed domestically each year. While this has been a productive strategy in increasing agricultural production and maintaining high yields, groundwater resources are depleting at a quicker rate than natural resources can replace. This issue gains relevance as climate variability concurrently adds to yearly fluctuations in farmer demand for irrigation each year, which can create high risk for farmers that depend on consistent yields, but do not have access to dwindling water resources. This study investigates variability in groundwater levels from 2005 to 2013 in relation to crop prices and production by analyzing district-level datasets made available through India's government. Through this analysis, we show the impact of groundwater variability on price variability, crop yield, and production during these years. By examining this nine-year timescale, we extend our analysis to forthcoming years to demonstrate the increasing importance of groundwater resources in irrigation, and suggest strategies to reduce the impact of groundwater shortages on crop production and prices.

Analysis of graphic representation ability in oscillation phenomena

NASA Astrophysics Data System (ADS)

Dewi, A. R. C.; Putra, N. M. D.; Susilo

2018-03-01

This study aims to investigates how the ability of students to representation graphs of linear function and harmonic function in understanding of oscillation phenomena. Method of this research used mix methods with concurrent embedded design. The subjects were 35 students of class X MIA 3 SMA 1 Bae Kudus. Data collection through giving essays and interviews that lead to the ability to read and draw graphs in material of Hooke's law and oscillation characteristics. The results of study showed that most of the students had difficulty in drawing graph of linear function and harmonic function of deviation with time. Students’ difficulties in drawing the graph of linear function is the difficulty of analyzing the variable data needed in graph making, confusing the placement of variable data on the coordinate axis, the difficulty of determining the scale interval on each coordinate, and the variation of how to connect the dots forming the graph. Students’ difficulties in representing the graph of harmonic function is to determine the time interval of sine harmonic function, the difficulty to determine the initial deviation point of the drawing, the difficulty of finding the deviation equation of the case of oscillation characteristics and the confusion to different among the maximum deviation (amplitude) with the length of the spring caused the load.Complexity of the characteristic attributes of the oscillation phenomena graphs, students tend to show less well the ability of graphical representation of harmonic functions than the performance of the graphical representation of linear functions.

Advantages of concurrent biochemotherapy modified by decrescendo interleukin-2, granulocyte colony-stimulating factor, and tamoxifen for patients with metastatic melanoma.

PubMed

O'Day, S J; Gammon, G; Boasberg, P D; Martin, M A; Kristedja, T S; Guo, M; Stern, S; Edwards, S; Fournier, P; Weisberg, M; Cannon, M; Fawzy, N W; Johnson, T D; Essner, R; Foshag, L J; Morton, D L

1999-09-01

Concurrent biochemotherapy results in high response rates but also significant toxicity in patients with metastatic melanoma. We attempted to improve its efficacy and decrease its toxicity by using decrescendo dosing of interleukin-2 (IL-2), posttreatment granulocyte colony-stimulating factor (G-CSF), and low-dose tamoxifen. Forty-five patients with poor prognosis metastatic melanoma were treated at a community hospital inpatient oncology unit affiliated with the John Wayne Cancer Institute (Santa Monica, CA) between July 1995 and September 1997. A 5-day modified concurrent biochemotherapy regimen of dacarbazine, vinblastine, cisplatin, decrescendo IL-2, interferon alfa-2b, and tamoxifen was repeated at 21-day intervals. G-CSF was administered beginning on day 6 for 7 to 10 days. The overall response rate was 57% (95% confidence interval, 42% to 72%), the complete response rate was 23%, and the partial response rate was 34%. Complete remissions were achieved in an additional 11% of patients by surgical resection of residual disease after biochemotherapy. The median time to progression was 6.3 months and the median duration of survival was 11.4 months. At a maximum follow-up of 36 months (range, 10 to 36 months), 32% of patients are alive and 14% remain free of disease. Decrescendo IL-2 dosing and administration of G-CSF seemed to reduce toxicity, length of hospital stay, and readmission rates. No patient required intensive care unit monitoring, and there were no treatment-related deaths. The data from this study indicate that the modified concurrent biochemotherapy regimen reduces the toxicity of concurrent biochemotherapy with no apparent decrease in response rate in patients with poor prognosis metastatic melanoma.

Effects of concurrent physical and cognitive demands on muscle activity and heart rate variability in a repetitive upper-extremity precision task.

PubMed

Srinivasan, Divya; Mathiassen, Svend Erik; Hallman, David M; Samani, Afshin; Madeleine, Pascal; Lyskov, Eugene

2016-01-01

Most previous studies of concurrent physical and cognitive demands have addressed tasks of limited relevance to occupational work, and with dissociated physical and cognitive task components. This study investigated effects on muscle activity and heart rate variability of executing a repetitive occupational task with an added cognitive demand integral to correct task performance. Thirty-five healthy females performed 7.5 min of standardized repetitive pipetting work in a baseline condition and a concurrent cognitive condition involving a complex instruction for correct performance. Average levels and variabilities of electromyographic activities in the upper trapezius and extensor carpi radialis (ECR) muscles were compared between these two conditions. Heart rate and heart rate variability were also assessed to measure autonomic nervous system activation. Subjects also rated perceived fatigue in the neck-shoulder region, as well as exertion. Concurrent cognitive demands increased trapezius muscle activity from 8.2% of maximum voluntary exertion (MVE) in baseline to 9.0% MVE (p = 0.0005), but did not significantly affect ECR muscle activity, heart rate, heart rate variability, perceived fatigue or exertion. Trapezius muscle activity increased by about 10%, without any accompanying cardiovascular response to indicate increased sympathetic activation. We suggest this slight increase in trapezius muscle activity to be due to changed muscle activation patterns within or among shoulder muscles. The results suggest that it may be possible to introduce modest cognitive demands necessary for correct performance in repetitive precision work without any major physiological effects, at least in the short term.

Physical and mental effort disrupts the implicit sense of agency.

PubMed

Howard, Emma E; Edwards, S Gareth; Bayliss, Andrew P

2016-12-01

We investigated the effect of effort on implicit agency ascription for actions performed under varying levels of physical effort or cognitive load. People are able to estimate the interval between two events accurately, but they underestimate the interval between their own actions and their outcomes. This effect is known as 'intentional binding', and may provide feedback regarding the consequences of our actions. Concurrently with the interval reproduction task, our participants pulled sports resistance bands at high and low resistance levels (Experiments 1 and 2), or performed a working memory task with high and low set-sizes (Experiment 3). Intentional binding was greater under low than high effort. When the effort was task-related (Experiment 1), this effect depended on the individual's explicit appraisal of exertion, while the effect of effort was evident at the group level when the effort was task-unrelated (physical, Experiment 2; mental, Experiment 3). These findings imply that the process of intentional binding is compromised when cognitive resources are depleted, either through physical or mental strain. We discuss this notion in relation to the integration of direct sensorimotor feedback with signals of agency and other instances of cognitive resource depletion and action control during strain. Copyright © 2016 Elsevier B.V. All rights reserved.

Preparing hearts and minds: cardiac slowing and a cortical inhibitory network.

PubMed

Jennings, J R; van der Molen, M W; Tanase, C

2009-11-01

Preparing for a cued, speeded response induces a set of physiological changes. A review of the psychophysiology of preparation suggested that inhibition of action was an important process among the constellation of changes constituting attentive preparation. The current experiment combined event-related functional magnetic resonance imaging and cardiac inter-beat interval measures in an experiment that compared preparing for a response, watching stimuli without responding, and responding in the absence of preparation. Ten college-aged participants were tested in an initial psychophysiological experiment followed by two scanning sessions during which reverse spiral imaging was performed concurrent with inter-beat interval measurement. Two analytic approaches were used to confirm blood oxygenation level dependent responses during preparation, and these converged to show inferior prefrontal and related subthalamic nuclei activity in the context of other known changes related to brain attentional networks. Subthalamic nuclei changes were related to the depth of preparatory cardiac deceleration. This pattern of findings suggests that preparation involves the activation of a complex inhibitory neural network implicating brain and autonomic nervous systems.

The development and evaluation of accident predictive models

NASA Astrophysics Data System (ADS)

Maleck, T. L.

1980-12-01

A mathematical model that will predict the incremental change in the dependent variables (accident types) resulting from changes in the independent variables is developed. The end product is a tool for estimating the expected number and type of accidents for a given highway segment. The data segments (accidents) are separated in exclusive groups via a branching process and variance is further reduced using stepwise multiple regression. The standard error of the estimate is calculated for each model. The dependent variables are the frequency, density, and rate of 18 types of accidents among the independent variables are: district, county, highway geometry, land use, type of zone, speed limit, signal code, type of intersection, number of intersection legs, number of turn lanes, left-turn control, all-red interval, average daily traffic, and outlier code. Models for nonintersectional accidents did not fit nor validate as well as models for intersectional accidents.

Comparison of dehydroepiandrosterone (DHEA) and pregnanolone with existing pharmacotherapies for alcohol abuse on ethanol- and food-maintained responding in male rats.

PubMed

Hulin, Mary W; Lawrence, Michelle N; Amato, Russell J; Weed, Peter F; Winsauer, Peter J

2015-03-01

The present study compared two putative pharmacotherapies for alcohol abuse and dependence, dehydroepiandrosterone (DHEA) and pregnanolone, with two Food and Drug Administration (FDA)-approved pharmacotherapies, naltrexone and acamprosate. Experiment 1 assessed the effects of different doses of DHEA, pregnanolone, naltrexone, and acamprosate on both ethanol- and food-maintained responding under a multiple fixed-ratio (FR)-10 FR-20 schedule, respectively. Experiment 2 assessed the effects of different mean intervals of food presentation on responding for ethanol under a FR-10 variable-interval (VI) schedule, whereas Experiment 3 assessed the effects of a single dose of each drug under a FR-10 VI-80 schedule. In Experiment 1, all four drugs dose-dependently decreased response rate for both food and ethanol, although differences in the rate-decreasing effects were apparent among the drugs. DHEA and pregnanolone decreased ethanol-maintained responding more potently than food-maintained responding, whereas the reverse was true for naltrexone. Acamprosate decreased responding for both reinforcers with equal potency. In Experiment 2, different mean intervals of food presentation significantly affected the number of food reinforcers obtained per session; however, changes in the number of food reinforcements did not significantly affect responding for ethanol. Under the FR-10 VI-80 schedule in Experiment 3, only naltrexone significantly decreased both the dose of alcohol presented and blood ethanol concentration (BEC). Acamprosate and pregnanolone had no significant effects on any of the dependent measures, whereas DHEA significantly decreased BEC, but did not significantly decrease response rate or the dose presented. In summary, DHEA and pregnanolone decreased ethanol-maintained responding more potently than food-maintained responding under a multiple FR-10 FR-20 schedule, and were more selective for decreasing ethanol self-administration than either naltrexone or acamprosate under that schedule. Experiment 2 showed that ethanol intake was relatively independent of the interval of reinforcement in the food-maintained component, and Experiment 3 showed that naltrexone was the most effective drug at the doses tested when the interval for food reinforcement was low and maintained under a variable-interval schedule. Copyright © 2015 Elsevier Inc. All rights reserved.

Working nonstandard schedules and variable shifts in low-income families: associations with parental psychological well-being, family functioning, and child well-being.

PubMed

Hsueh, JoAnn; Yoshikawa, Hirokazu

2007-05-01

Longitudinal data from the New Hope Project--an experimental evaluation of a work-based antipoverty program in Milwaukee, Wisconsin--was used to explore concurrent and lagged associations of nonstandard schedules and variable shifts with parental psychological well-being, regularity of family mealtimes, and child well-being among low-income families. Working a combination of variable shifts and nonstandard hours was associated concurrently with lower teacher-reported school performance and engagement and higher levels of externalizing behavior problems. Fixed nonstandard schedules were associated with lagged decreases in parent-reported school performance, whereas working variable shifts was associated with lagged increases in parent-reported school performance. Copyright (c) 2007 APA, all rights reserved.

Virtual active touch using randomly patterned intracortical microstimulation.

PubMed

O'Doherty, Joseph E; Lebedev, Mikhail A; Li, Zheng; Nicolelis, Miguel A L

2012-01-01

Intracortical microstimulation (ICMS) has promise as a means for delivering somatosensory feedback in neuroprosthetic systems. Various tactile sensations could be encoded by temporal, spatial, or spatiotemporal patterns of ICMS. However, the applicability of temporal patterns of ICMS to artificial tactile sensation during active exploration is unknown, as is the minimum discriminable difference between temporally modulated ICMS patterns. We trained rhesus monkeys in an active exploration task in which they discriminated periodic pulse-trains of ICMS (200 Hz bursts at a 10 Hz secondary frequency) from pulse trains with the same average pulse rate, but distorted periodicity (200 Hz bursts at a variable instantaneous secondary frequency). The statistics of the aperiodic pulse trains were drawn from a gamma distribution with mean inter-burst intervals equal to those of the periodic pulse trains. The monkeys distinguished periodic pulse trains from aperiodic pulse trains with coefficients of variation 0.25 or greater. Reconstruction of movement kinematics, extracted from the activity of neuronal populations recorded in the sensorimotor cortex concurrent with the delivery of ICMS feedback, improved when the recording intervals affected by ICMS artifacts were removed from analysis. These results add to the growing evidence that temporally patterned ICMS can be used to simulate a tactile sense for neuroprosthetic devices.

Nonparametric methods in actigraphy: An update

PubMed Central

Gonçalves, Bruno S.B.; Cavalcanti, Paula R.A.; Tavares, Gracilene R.; Campos, Tania F.; Araujo, John F.

2014-01-01

Circadian rhythmicity in humans has been well studied using actigraphy, a method of measuring gross motor movement. As actigraphic technology continues to evolve, it is important for data analysis to keep pace with new variables and features. Our objective is to study the behavior of two variables, interdaily stability and intradaily variability, to describe rest activity rhythm. Simulated data and actigraphy data of humans, rats, and marmosets were used in this study. We modified the method of calculation for IV and IS by modifying the time intervals of analysis. For each variable, we calculated the average value (IVm and ISm) results for each time interval. Simulated data showed that (1) synchronization analysis depends on sample size, and (2) fragmentation is independent of the amplitude of the generated noise. We were able to obtain a significant difference in the fragmentation patterns of stroke patients using an IVm variable, while the variable IV60 was not identified. Rhythmic synchronization of activity and rest was significantly higher in young than adults with Parkinson׳s when using the ISM variable; however, this difference was not seen using IS60. We propose an updated format to calculate rhythmic fragmentation, including two additional optional variables. These alternative methods of nonparametric analysis aim to more precisely detect sleep–wake cycle fragmentation and synchronization. PMID:26483921

Variables selection methods in near-infrared spectroscopy.

PubMed

Xiaobo, Zou; Jiewen, Zhao; Povey, Malcolm J W; Holmes, Mel; Hanpin, Mao

2010-05-14

Near-infrared (NIR) spectroscopy has increasingly been adopted as an analytical tool in various fields, such as the petrochemical, pharmaceutical, environmental, clinical, agricultural, food and biomedical sectors during the past 15 years. A NIR spectrum of a sample is typically measured by modern scanning instruments at hundreds of equally spaced wavelengths. The large number of spectral variables in most data sets encountered in NIR spectral chemometrics often renders the prediction of a dependent variable unreliable. Recently, considerable effort has been directed towards developing and evaluating different procedures that objectively identify variables which contribute useful information and/or eliminate variables containing mostly noise. This review focuses on the variable selection methods in NIR spectroscopy. Selection methods include some classical approaches, such as manual approach (knowledge based selection), "Univariate" and "Sequential" selection methods; sophisticated methods such as successive projections algorithm (SPA) and uninformative variable elimination (UVE), elaborate search-based strategies such as simulated annealing (SA), artificial neural networks (ANN) and genetic algorithms (GAs) and interval base algorithms such as interval partial least squares (iPLS), windows PLS and iterative PLS. Wavelength selection with B-spline, Kalman filtering, Fisher's weights and Bayesian are also mentioned. Finally, the websites of some variable selection software and toolboxes for non-commercial use are given. Copyright 2010 Elsevier B.V. All rights reserved.

Prediction of Malaysian monthly GDP

NASA Astrophysics Data System (ADS)

Hin, Pooi Ah; Ching, Soo Huei; Yeing, Pan Wei

2015-12-01

The paper attempts to use a method based on multivariate power-normal distribution to predict the Malaysian Gross Domestic Product next month. Letting r(t) be the vector consisting of the month-t values on m selected macroeconomic variables, and GDP, we model the month-(t+1) GDP to be dependent on the present and l-1 past values r(t), r(t-1),…,r(t-l+1) via a conditional distribution which is derived from a [(m+1)l+1]-dimensional power-normal distribution. The 100(α/2)% and 100(1-α/2)% points of the conditional distribution may be used to form an out-of sample prediction interval. This interval together with the mean of the conditional distribution may be used to predict the month-(t+1) GDP. The mean absolute percentage error (MAPE), estimated coverage probability and average length of the prediction interval are used as the criterions for selecting the suitable lag value l-1 and the subset from a pool of 17 macroeconomic variables. It is found that the relatively better models would be those of which 2 ≤ l ≤ 3, and involving one or two of the macroeconomic variables given by Market Indicative Yield, Oil Prices, Exchange Rate and Import Trade.

Concurrent sympathetic activation and vagal withdrawal in hyperthyroidism: Evidence from detrended fluctuation analysis of heart rate variability

NASA Astrophysics Data System (ADS)

Chen, Jin-Long; Shiau, Yuo-Hsien; Tseng, Yin-Jiun; Chiu, Hung-Wen; Hsiao, Tzu-Chien; Wessel, Niels; Kurths, Jürgen; Chu, Woei-Chyn

2010-05-01

Despite many previous studies on the association between hyperthyroidism and the hyperadrenergic state, controversies still exist. Detrended fluctuation analysis (DFA) is a well recognized method in the nonlinear analysis of heart rate variability (HRV), and it has physiological significance related to the autonomic nervous system. In particular, an increased short-term scaling exponent α1 calculated from DFA is associated with both increased sympathetic activity and decreased vagal activity. No study has investigated the DFA of HRV in hyperthyroidism. This study was designed to assess the sympathovagal balance in hyperthyroidism. We performed the DFA along with the linear analysis of HRV in 36 hyperthyroid Graves’ disease patients (32 females and 4 males; age 30 ± 1 years, means ± SE) and 36 normal controls matched by sex, age and body mass index. Compared with the normal controls, the hyperthyroid patients revealed a significant increase ( P<0.001) in α1 (hyperthyroid 1.28±0.04 versus control 0.91±0.02), long-term scaling exponent α2 (1.05±0.02 versus 0.90±0.01), overall scaling exponent α (1.11±0.02 versus 0.89±0.01), low frequency power in normalized units (LF%) and the ratio of low frequency power to high frequency power (LF/HF); and a significant decrease ( P<0.001) in the standard deviation of the R-R intervals (SDNN) and high frequency power (HF). In conclusion, hyperthyroidism is characterized by concurrent sympathetic activation and vagal withdrawal. This sympathovagal imbalance state in hyperthyroidism helps to explain the higher prevalence of atrial fibrillation and exercise intolerance among hyperthyroid patients.

RELIABILITY CONCERNS IN THE REPEATED COMPUTERIZED ASSESSMENT OF ATTENTION IN CHILDREN

PubMed Central

Zabel, T. Andrew; von Thomsen, Christian; Cole, Carolyn; Martin, Rebecca; Mahone, E. Mark

2010-01-01

Assessment of attentional processes via computerized assessment is frequently used to quantify intra-individual cognitive improvement or decline in response to treatment. However, assessment of intra-individual change is highly dependent on sufficient test reliability. We examined the test–retest reliability of selected variables from one popular computerized continuous performance test (CPT)—i.e., the Conners’ CPT – Second Edition (CPT-II). Participants were 39 healthy children (20 girls) ages 6–18 without intellectual impairment (mean PPVT-III SS = 102.6), LD, or psychiatric disorders (DICA-IV). Test–retest reliability over the 3–8 month interval (mean = 6 months) was acceptable (Intraclass Correlations [ICC] = .82 to .92) on comparison measures (Beery Test of Visual Perception, WISC-IV Block Design, PPVT-III). In contrast, test–retest reliability was only modest for CPT-II raw scores (ICCs ranging from .62 to .82) and T-scores (ICCs ranging from .33 to .65) for variables of interest (Omissions, Commissions, Variability, Hit Reaction Time, and Attentiveness). Using test–retest reliability information published in the CPT-II manual, 90% confidence intervals based on reliable change index (RCI) methodology were constructed to examine the significance of test–retest difference/change scores. Of the participants in this sample of typically developing youth, 30% generated intra-individual changes in T-scores on the Omissions and Attentiveness variables that exceeded the 90% confidence intervals and qualified as “statistically rare” changes in score. These results suggest a considerable degree of normal variability in CPT-II test scores over extended test–retest intervals, and suggest a need for caution when interpreting test score changes in neurologically unstable clinical populations. PMID:19452302

Combinations of response-reinforcer relations in periodic and aperiodic schedules.

PubMed

Kuroda, Toshikazu; Cançado, Carlos R X; Lattal, Kennon A; Elcoro, Mirari; Dickson, Chata A; Cook, James E

2013-03-01

Key pecking of 4 pigeons was studied under a two-component multiple schedule in which food deliveries were arranged according to a fixed and a variable interfood interval. The percentage of response-dependent food in each component was varied, first in ascending (0, 10, 30, 70 and 100%) and then in descending orders, in successive conditions. The change in response rates was positively related to the percentage of response-dependent food in each schedule component. Across conditions, positively accelerated and linear patterns of responding occurred consistently in the fixed and variable components, respectively. These results suggest that the response-food dependency determines response rates in periodic and aperiodic schedules, and that the temporal distribution of food determines response patterns independently of the response-food dependency. Running rates, but not postfood pauses, also were positively related to the percentage of dependent food in each condition, in both fixed and variable components. Thus, the relation between overall response rate and the percentage of dependent food was mediated by responding that occurred after postfood pausing. The findings together extend previous studies wherein the dependency was either always present or absent, and increase the generality of the effects of variations in the response-food dependency from aperiodic to periodic schedules. © Society for the Experimental Analysis of Behavior.

Short-term variability in QT interval and ventricular arrhythmias induced by dofetilide are dependent on high-frequency autonomic oscillations

PubMed Central

Champeroux, P; Thireau, J; Judé, S; Laigot-Barbé, C; Maurin, A; Sola, M L; Fowler, J S L; Richard, S; Le Guennec, J Y

2015-01-01

Background and Purpose The present study was undertaken to investigate an effect of dofetilide, a potent arrhythmic blocker of the voltage-gated K+ channel, hERG, on cardiac autonomic control. Combined with effects on ardiomyocytes, these properties could influence its arrhythmic potency. Experimental Approach The short-term variability of beat-to-beat QT interval (STVQT), induced by dofetilide is a strong surrogate of Torsades de pointes liability. Involvement of autonomic modulation in STVQT was investigated in healthy cynomolgus monkeys and beagle dogs by power spectral analysis under conditions of autonomic blockade with hexamethonium. Key Results Increase in STVQT induced by dofetilide in monkeys and dogs was closely associated with an enhancement of endogenous heart rate and QT interval high-frequency (HF) oscillations. These effects were fully suppressed under conditions of autonomic blockade with hexamethonium. Ventricular arrhythmias, including Torsades de pointes in monkeys, were prevented in both species when HF oscillations were suppressed by autonomic blockade. Similar enhancements of heart rate HF oscillations were found in dogs with other hERG blockers described as causing Torsades de pointes in humans. Conclusions and Implications These results demonstrate for the first time that beat-to-beat ventricular repolarization variability and ventricular arrhythmias induced by dofetilide are dependent on endogenous HF autonomic oscillations in heart rate. When combined with evidence of hERG-blocking properties, enhancement of endogenous HF oscillations in heart rate could constitute an earlier and more sensitive biomarker than STVQT for Torsades de pointes liability, applicable to preclinical regulatory studies conducted in healthy animals. PMID:25625756

Short-term variability in QT interval and ventricular arrhythmias induced by dofetilide are dependent on high-frequency autonomic oscillations.

PubMed

Champeroux, P; Thireau, J; Judé, S; Laigot-Barbé, C; Maurin, A; Sola, M L; Fowler, J S L; Richard, S; Le Guennec, J Y

2015-06-01

The present study was undertaken to investigate an effect of dofetilide, a potent arrhythmic blocker of the voltage-gated K(+) channel, hERG, on cardiac autonomic control. Combined with effects on ardiomyocytes, these properties could influence its arrhythmic potency. The short-term variability of beat-to-beat QT interval (STVQT ), induced by dofetilide is a strong surrogate of Torsades de pointes liability. Involvement of autonomic modulation in STVQT was investigated in healthy cynomolgus monkeys and beagle dogs by power spectral analysis under conditions of autonomic blockade with hexamethonium. Increase in STVQT induced by dofetilide in monkeys and dogs was closely associated with an enhancement of endogenous heart rate and QT interval high-frequency (HF) oscillations. These effects were fully suppressed under conditions of autonomic blockade with hexamethonium. Ventricular arrhythmias, including Torsades de pointes in monkeys, were prevented in both species when HF oscillations were suppressed by autonomic blockade. Similar enhancements of heart rate HF oscillations were found in dogs with other hERG blockers described as causing Torsades de pointes in humans. These results demonstrate for the first time that beat-to-beat ventricular repolarization variability and ventricular arrhythmias induced by dofetilide are dependent on endogenous HF autonomic oscillations in heart rate. When combined with evidence of hERG-blocking properties, enhancement of endogenous HF oscillations in heart rate could constitute an earlier and more sensitive biomarker than STVQT for Torsades de pointes liability, applicable to preclinical regulatory studies conducted in healthy animals. © 2015 The British Pharmacological Society.

The time-domain behavior of power-law noises. [of many geophysical phenomena

NASA Technical Reports Server (NTRS)

Agnew, Duncan C.

1992-01-01

The power spectra of many geophysical phenomena are well approximated by a power-law dependence on frequency or wavenumber. A simple expression for the root-mean-square variability of a process with such a spectrum over an interval of time or space is derived. The resulting expression yields the powerlaw time dependence characteristic of fractal processes, but can be generalized to give the temporal variability for more general spectral behaviors. The method is applied to spectra of crustal strain (to show what size of strain events can be detected over periods of months to seconds) and of sea level (to show the difficulty of extracting long-term rates from short records).

Accounting for Test Variability through Sizing Local Domains in Sequential Design Optimization with Concurrent Calibration-Based Model Validation

DTIC Science & Technology

2013-08-01

in Sequential Design Optimization with Concurrent Calibration-Based Model Validation Dorin Drignei 1 Mathematics and Statistics Department...Validation 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Dorin Drignei; Zissimos Mourelatos; Vijitashwa Pandey

Optical, near, infrared and ultraviolet monitoring of the Seyfert 1 galaxy Markarian 335

NASA Technical Reports Server (NTRS)

Shrader, Chris R.; Sun, W.-H.; Turner, T. J.; Hintzen, P. M.

1990-01-01

Preliminary results of a multifrequency monitoring campaign for the bright, Seyfert 1 galactic nuclei Mkn335 are presented. Nearly uniform sampling at 3 day intervals is achieved quasi simultaneously at each wavelength band. Wavelength dependent variability is seen at the 20 to 30 percent level. Interpretation of variability in terms of geometrically thin, optically thick accretion disk models is discussed. The inferred blackhole masses and accretion rates are discussed. Possible correlation between continuum and emission line variations is discussed.

Specifying the behavior of concurrent systems

NASA Technical Reports Server (NTRS)

Furtek, F. C.

1984-01-01

A framework for rigorously specifying the behavior of concurrent systems is proposed. It is based on the view of a concurrent system as a collection of interacting processes but no assumptions are made about the mechanisms for process synchronization and communication. A formal language is described that permits the expression of a broad range of logical and timing dependencies.

Concurrent-Chains Schedules as a Method to Study Choice between Alcohol-Associated Conditioned Reinforcers

ERIC Educational Resources Information Center

Jimenez-Gomez, Corina; Shahan, Timothy A.

2012-01-01

An extensive body of research using concurrent-chains schedules of reinforcement has shown that choice for one of two differentially valued food-associated stimuli is dependent upon the overall temporal context in which those stimuli are embedded. The present experiments examined whether the concurrent chains procedure was useful for the study of…

Confidence Intervals and "F" Tests for Intraclass Correlation Coefficients Based on Three-Way Mixed Effects Models

ERIC Educational Resources Information Center

Zhou, Hong; Muellerleile, Paige; Ingram, Debra; Wong, Seok P.

2011-01-01

Intraclass correlation coefficients (ICCs) are commonly used in behavioral measurement and psychometrics when a researcher is interested in the relationship among variables of a common class. The formulas for deriving ICCs, or generalizability coefficients, vary depending on which models are specified. This article gives the equations for…

Suppressive and Facilitative Effects of Shock Intensity and Interresponse Times Followed by Shock

ERIC Educational Resources Information Center

Everly, Jessica B.; Perone, Michael

2012-01-01

Although response-dependent shock often suppresses responding, response facilitation can occur. In two experiments, we examined the suppressive and facilitative effects of shock by manipulating shock intensity and the interresponse times that produced shock. Rats' lever presses were reinforced on a variable-interval 40-s schedule of food…

Method and apparatus for assessing cardiovascular risk

NASA Technical Reports Server (NTRS)

Albrecht, Paul (Inventor); Bigger, J. Thomas (Inventor); Cohen, Richard J. (Inventor)

1998-01-01

The method for assessing risk of an adverse clinical event includes detecting a physiologic signal in the subject and determining from the physiologic signal a sequence of intervals corresponding to time intervals between heart beats. The long-time structure of fluctuations in the intervals over a time period of more than fifteen minutes is analyzed to assess risk of an adverse clinical event. In a preferred embodiment, the physiologic signal is an electrocardiogram and the time period is at least fifteen minutes. A preferred method for analyzing the long-time structure variability in the intervals includes computing the power spectrum and fitting the power spectrum to a power law dependence on frequency over a selected frequency range such as 10.sup.-4 to 10.sup.-2 Hz. Characteristics of the long-time structure fluctuations in the intervals is used to assess risk of an adverse clinical event.

Self-stimulating rats combine subjective reward magnitude and subjective reward rate multiplicatively.

PubMed

Leon, M I; Gallistel, C R

1998-07-01

For rats that bar pressed for intracranial electrical stimulation in a 2-lever matching paradigm with concurrent variable interval schedules of reward, the authors found that the time allocation ratio is based on a multiplicative combination of the ratio of subjective reward magnitudes and the ratio of the rates of reward. Multiplicative combining was observed in a range covering approximately 2 orders of magnitude in the ratio of the rates of reward from about 1:10 to 10:1) and an order of magnitude change in the size of rewards. After determining the relation between the pulse frequency of stimulation and subjective reward magnitude, the authors were able to predict from knowledge of the subjective magnitudes of the rewards and the obtained relative rates of reward the subject's time allocation ratio over a range in which it varied by more than 3 orders of magnitude.

Concurrent E-Cigarette Use During Tobacco Dependence Treatment in Primary Care Settings: Association With Smoking Cessation at Three and Six Months.

PubMed

Zawertailo, Laurie; Pavlov, Dmytro; Ivanova, Anna; Ng, Ginnie; Baliunas, Dolly; Selby, Peter

2017-02-01

Electronic cigarettes (e-cigarettes) are being used as cessation aids by many smokers despite a lack of empirical evidence regarding their safety and efficacy. We analyzed the association of e-cigarette use and smoking abstinence in a population of smokers accessing standard smoking cessation treatment (nicotine replacement therapy [NRT] plus behavioral counseling) through primary care clinics in Ontario, Canada. Participants were recruited through 187 primary care clinics across Ontario, Canada and were eligible for up to 26 weeks of brief behavioral counseling and individualized dosing of NRT at no cost. Adjusted logistic regression models were used to examine the association between concurrent e-cigarette use and smoking abstinence at 3- and 6-month follow-ups. Of the 6526 participants who completed a 3-month follow-up, 18.1% reported using an e-cigarette while in treatment. The majority of e-cigarette users (78.2%) reported using an e-cigarette for smoking cessation. At 3-month follow-up, e-cigarette use was negatively associated with abstinence after controlling for confounders (adjusted odds ratio [AOR] = 0.706, p < .001, 95% confidence interval [CI] = 0.607-0.820). E-cigarette use was also negatively associated with abstinence at 6-month follow-up (AOR = 0.502, p < .001, 95% CI = 0.393-0.640). E-cigarette use was negatively associated with successful quitting in this large community sample of smokers accessing standard evidence-based smoking cessation treatment through primary care clinics, even after adjusting for covariates such as severity of tobacco dependence, gender, and age. The findings suggest that concurrent use of e-cigarettes with NRT may harm cessation attempts. This study confirms previous findings from observational studies regarding the negative association between e-cigarette use and smoking cessation, but in a large cohort of smokers enrolled in an evidence-based treatment program. The implications of these findings are that concurrent use of e-cigarettes during a quit attempt utilizing cost-free evidence-based treatment (NRT plus behavioral counseling) does not confer any added benefit and may hamper successful quitting. © The Author 2016. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Risk factors for low birth weight according to the multiple logistic regression model. A retrospective cohort study in José María Morelos municipality, Quintana Roo, Mexico.

PubMed

Franco Monsreal, José; Tun Cobos, Miriam Del Ruby; Hernández Gómez, José Ricardo; Serralta Peraza, Lidia Esther Del Socorro

2018-01-17

Low birth weight has been an enigma for science over time. There have been many researches on its causes and its effects. Low birth weight is an indicator that predicts the probability of a child surviving. In fact, there is an exponential relationship between weight deficit, gestational age, and perinatal mortality. Multiple logistic regression is one of the most expressive and versatile statistical instruments available for the analysis of data in both clinical and epidemiology settings, as well as in public health. To assess in a multivariate fashion the importance of 17 independent variables in low birth weight (dependent variable) of children born in the Mayan municipality of José María Morelos, Quintana Roo, Mexico. Analytical observational epidemiological cohort study with retrospective temporality. Births that met the inclusion criteria occurred in the "Hospital Integral Jose Maria Morelos" of the Ministry of Health corresponding to the Maya municipality of Jose Maria Morelos during the period from August 1, 2014 to July 31, 2015. The total number of newborns recorded was 1,147; 84 of which (7.32%) had low birth weight. To estimate the independent association between the explanatory variables (potential risk factors) and the response variable, a multiple logistic regression analysis was performed using the IBM SPSS Statistics 22 software. In ascending numerical order values of odds ratio > 1 indicated the positive contribution of explanatory variables or possible risk factors: "unmarried" marital status (1.076, 95% confidence interval: 0.550 to 2.104); age at menarche ≤ 12 years (1.08, 95% confidence interval: 0.64 to 1.84); history of abortion(s) (1.14, 95% confidence interval: 0.44 to 2.93); maternal weight < 50 kg (1.51, 95% confidence interval: 0.83 to 2.76); number of prenatal consultations ≤ 5 (1.86, 95% confidence interval: 0.94 to 3.66); maternal age ≥ 36 years (3.5, 95% confidence interval: 0.40 to 30.47); maternal age ≤ 19 years (3.59, 95% confidence interval: 0.43 to 29.87); number of deliveries = 1 (3.86, 95% confidence interval: 0.33 to 44.85); personal pathological history (4.78, 95% confidence interval: 2.16 to 10.59); pathological obstetric history (5.01, 95% confidence interval: 1.66 to 15.18); maternal height < 150 cm (5.16, 95% confidence interval: 3.08 to 8.65); number of births ≥ 5 (5.99, 95% confidence interval: 0.51 to 69.99); and smoking (15.63, 95% confidence interval: 1.07 to 227.97). Four of the independent variables (personal pathological history, obstetric pathological history, maternal stature <150 centimeters and smoking) showed a significant positive contribution, thus they can be considered as clear risk factors for low birth weight. The use of the logistic regression model in the Mayan municipality of José María Morelos, will allow estimating the probability of low birth weight for each pregnant woman in the future, which will be useful for the health authorities of the region.

Outcomes of Concurrent Operations: Results From the American College of Surgeons' National Surgical Quality Improvement Program.

PubMed

Liu, Jason B; Berian, Julia R; Ban, Kristen A; Liu, Yaoming; Cohen, Mark E; Angelos, Peter; Matthews, Jeffrey B; Hoyt, David B; Hall, Bruce L; Ko, Clifford Y

2017-09-01

To determine whether concurrently performed operations are associated with an increased risk for adverse events. Concurrent operations occur when a surgeon is simultaneously responsible for critical portions of 2 or more operations. How this practice affects patient outcomes is unknown. Using American College of Surgeons' National Surgical Quality Improvement Program data from 2014 to 2015, operations were considered concurrent if they overlapped by ≥60 minutes or in their entirety. Propensity-score-matched cohorts were constructed to compare death or serious morbidity (DSM), unplanned reoperation, and unplanned readmission in concurrent versus non-concurrent operations. Multilevel hierarchical regression was used to account for the clustered nature of the data while controlling for procedure and case mix. There were 1430 (32.3%) surgeons from 390 (77.7%) hospitals who performed 12,010 (2.3%) concurrent operations. Plastic surgery (n = 393 [13.7%]), otolaryngology (n = 470 [11.2%]), and neurosurgery (n = 2067 [8.4%]) were specialties with the highest proportion of concurrent operations. Spine procedures were the most frequent concurrent procedures overall (n = 2059/12,010 [17.1%]). Unadjusted rates of DSM (9.0% vs 7.1%; P < 0.001), reoperation (3.6% vs 2.7%; P < 0.001), and readmission (6.9% vs 5.1%; P < 0.001) were greater in the concurrent operation cohort versus the non-concurrent. After propensity score matching and risk-adjustment, there was no significant association of concurrence with DSM (odds ratio [OR] 1.08; 95% confidence interval [CI] 0.96-1.21), reoperation (OR 1.16; 95% CI 0.96-1.40), or readmission (OR 1.14; 95% CI 0.99-1.29). In these analyses, concurrent operations were not detected to increase the risk for adverse outcomes. These results do not lessen the need for further studies, continuous self-regulation and proactive disclosure to patients.

Determinants of birth interval in a rural Mediterranean population (La Alpujarra, Spain).

PubMed

Polo, V; Luna, F; Fuster, V

2000-10-01

The fertility pattern, in terms of birth intervals, in a rural population not practicing contraception belonging to La Alta Alpujarra Oriental (southeast Spain) is analyzed. During the first half of the 20th century, this population experienced a considerable degree of geographical and cultural isolation. Because of this population's high variability in fertility and therefore in birth intervals, the analysis was limited to a homogenous subsample of 154 families, each with at least five pregnancies. This limitation allowed us to analyze, among and within families, effects of a set of variables on the interbirth pattern, and to avoid possible problems of pseudoreplication. Information on birth date of the mother, age at marriage, children's birth date and death date, birth order, and frequency of miscarriages was collected. Our results indicate that interbirth intervals depend on an exponential effect of maternal age, especially significant after the age of 35. This effect is probably related to the biological degenerative processes of female fertility with age. A linear increase of birth intervals with birth order within families was found as well as a reduction of intervals among families experiencing an infant death. Our sample size was insufficient to detect a possible replacement behavior in the case of infant death. High natality and mortality rates, a secular decrease of natality rates, a log-normal birth interval, and family-size distributions suggest that La Alpujarra has been a natural fertility population following a demographic transition process.

Fuzzy simulation in concurrent engineering

NASA Technical Reports Server (NTRS)

Kraslawski, A.; Nystrom, L.

1992-01-01

Concurrent engineering is becoming a very important practice in manufacturing. A problem in concurrent engineering is the uncertainty associated with the values of the input variables and operating conditions. The problem discussed in this paper concerns the simulation of processes where the raw materials and the operational parameters possess fuzzy characteristics. The processing of fuzzy input information is performed by the vertex method and the commercial simulation packages POLYMATH and GEMS. The examples are presented to illustrate the usefulness of the method in the simulation of chemical engineering processes.

Specificity and transfer effects in time production skill: examining the role of attention.

PubMed

Wohldmann, Erica L; Healy, Alice F; Bourne, Lyle E

2012-05-01

Two experiments examined transfer of a prospective, time production skill under conditions involving changes in concurrent task requirements. Positive transfer of the time production skill might be expected only when the attentional demands of the concurrent task were held constant from training to test. However, some positive transfer was found even when the concurrent task at retraining was made either easier or more difficult than the concurrent task learned during training. The amount and direction of transfer depended more on the pacing of the stimuli in the secondary task than on the difficulty of the secondary task, even though difficulty affects attentional demands more. These findings are consistent with the procedural reinstatement principle of skill learning, by which transfer from one task to another depends on an overlap in procedures required by the two skills.

The impact of cognitive load on delayed recall.

PubMed

Camos, Valérie; Portrat, Sophie

2015-08-01

Recent studies have suggested that long-term retention of items studied in a working memory span task depends on the refreshing of memory items-more specifically, on the number of refreshing opportunities. However, it was previously shown that refreshing depends on the cognitive load of the concurrent task introduced in the working memory span task. Thus, cognitive load should determine the long-term retention of items assessed in a delayed-recall test if such retention relies on refreshing. In two experiments, while the amount of refreshing opportunities remained constant, we varied the cognitive load of the concurrent task by either introducing tasks differing in their attentional demands or varying the pace of the concurrent task. To verify that this effect was related to refreshing and not to any maintenance mechanism, we also manipulated the availability of subvocal rehearsal. Replicating previous results, increasing cognitive load reduced immediate recall. This increase also had a detrimental effect on delayed recall. Conversely, the addition of concurrent articulation reduced immediate but not delayed recall. This study shows that both working and episodic memory traces depend on the cognitive load of the concurrent task, whereas the use of rehearsal affects only working memory performance. These findings add further evidence of the dissociation between subvocal rehearsal and attentional refreshing.

A Semi-Preemptive Garbage Collector for Solid State Drives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Junghee; Kim, Youngjae; Shipman, Galen M

2011-01-01

NAND flash memory is a preferred storage media for various platforms ranging from embedded systems to enterprise-scale systems. Flash devices do not have any mechanical moving parts and provide low-latency access. They also require less power compared to rotating media. Unlike hard disks, flash devices use out-of-update operations and they require a garbage collection (GC) process to reclaim invalid pages to create free blocks. This GC process is a major cause of performance degradation when running concurrently with other I/O operations as internal bandwidth is consumed to reclaim these invalid pages. The invocation of the GC process is generally governedmore » by a low watermark on free blocks and other internal device metrics that different workloads meet at different intervals. This results in I/O performance that is highly dependent on workload characteristics. In this paper, we examine the GC process and propose a semi-preemptive GC scheme that can preempt on-going GC processing and service pending I/O requests in the queue. Moreover, we further enhance flash performance by pipelining internal GC operations and merge them with pending I/O requests whenever possible. Our experimental evaluation of this semi-preemptive GC sheme with realistic workloads demonstrate both improved performance and reduced performance variability. Write-dominant workloads show up to a 66.56% improvement in average response time with a 83.30% reduced variance in response time compared to the non-preemptive GC scheme.« less

Resistance to change and frequency of response-dependent stimuli uncorrelated with reinforcement.

PubMed

Podlesnik, Christopher A; Jimenez-Gomez, Corina; Ward, Ryan D; Shahan, Timothy A

2009-09-01

Stimuli uncorrelated with reinforcement have been shown to enhance response rates and resistance to disruption; however, the effects of different rates of stimulus presentations have not been assessed. In two experiments, we assessed the effects of adding different rates of response-dependent brief stimuli uncorrelated with primary reinforcement on relative response rates and resistance to change. In both experiments, pigeons responded on variable-interval 60-s schedules of food reinforcement in two components of a multiple schedule, and brief response-dependent keylight-color changes were added to one or both components. Although relative response rates were not systematically affected in either experiment, relative resistance to presession feeding and extinction were. In Experiment 1, adding stimuli on a variable-interval schedule to one component of a multiple schedule either at a low rate (1 per min) for one group or at a high rate (4 per min) for another group similarly increased resistance to disruption in the components with added stimuli. When high and low rates of stimuli were presented across components (i.e., within subjects) in Experiment 2, however, relative resistance to disruption was greater in the component presenting stimuli at a lower rate. These results suggest that stimuli uncorrelated with food reinforcement do not strengthen responding in the same way as primary reinforcers.

Missed opportunities for concurrent HIV-STD testing in an academic emergency department.

PubMed

Klein, Pamela W; Martin, Ian B K; Quinlivan, Evelyn B; Gay, Cynthia L; Leone, Peter A

2014-01-01

We evaluated emergency department (ED) provider adherence to guidelines for concurrent HIV-sexually transmitted disease (STD) testing within an expanded HIV testing program and assessed demographic and clinical factors associated with concurrent HIV-STD testing. We examined concurrent HIV-STD testing in a suburban academic ED with a targeted, expanded HIV testing program. Patients aged 18-64 years who were tested for syphilis, gonorrhea, or chlamydia in 2009 were evaluated for concurrent HIV testing. We analyzed demographic and clinical factors associated with concurrent HIV-STD testing using multivariate logistic regression with a robust variance estimator or, where applicable, exact logistic regression. Only 28.3% of patients tested for syphilis, 3.8% tested for gonorrhea, and 3.8% tested for chlamydia were concurrently tested for HIV during an ED visit. Concurrent HIV-syphilis testing was more likely among younger patients aged 25-34 years (adjusted odds ratio [AOR] = 0.36, 95% confidence interval [CI] 0.78, 2.10) and patients with STD-related chief complaints at triage (AOR=11.47, 95% CI 5.49, 25.06). Concurrent HIV-gonorrhea/chlamydia testing was more likely among men (gonorrhea: AOR=3.98, 95% CI 2.25, 7.02; chlamydia: AOR=3.25, 95% CI 1.80, 5.86) and less likely among patients with STD-related chief complaints at triage (gonorrhea: AOR=0.31, 95% CI 0.13, 0.82; chlamydia: AOR=0.21, 95% CI 0.09, 0.50). Concurrent HIV-STD testing in an academic ED remains low. Systematic interventions that remove the decision-making burden of ordering an HIV test from providers may increase HIV testing in this high-risk population of suspected STD patients.

Highly favorable physiological responses to concurrent resistance and high-intensity interval training during chemotherapy: the OptiTrain breast cancer trial.

PubMed

Mijwel, Sara; Backman, Malin; Bolam, Kate A; Olofsson, Emil; Norrbom, Jessica; Bergh, Jonas; Sundberg, Carl Johan; Wengström, Yvonne; Rundqvist, Helene

2018-05-01

Advanced therapeutic strategies are often accompanied by significant adverse effects, which warrant equally progressive countermeasures. Physical exercise has proven an effective intervention to improve physical function and reduce fatigue in patients undergoing chemotherapy. Effects of high-intensity interval training (HIIT) in this population are not well established although HIIT has proven effective in other clinical populations. The aim of the OptiTrain trial was to examine the effects of concurrent resistance and high-intensity interval training (RT-HIIT) or concurrent moderate-intensity aerobic and high-intensity interval training (AT-HIIT), to usual care (UC) on pain sensitivity and physiological outcomes in patients with breast cancer during chemotherapy. Two hundred and forty women were randomized to 16 weeks of RT-HIIT, AT-HIIT, or UC. cardiorespiratory fitness, muscle strength, body mass, hemoglobin levels, and pressure-pain threshold. Pre- to post-intervention, RT-HIIT (ES = 0.41) and AT-HIIT (ES = 0.42) prevented the reduced cardiorespiratory fitness found with UC. Handgrip strength (surgery side: RT-HIIT vs. UC: ES = 0.41, RT-HIIT vs. AT-HIIT: ES = 0.28; non-surgery side: RT-HIIT vs. UC: ES = 0.35, RT-HIIT vs. AT-HIIT: ES = 0.22) and lower-limb muscle strength (RT-HIIT vs. UC: ES = 0.66, RT-HIIT vs. AT-HIIT: ES = 0.23) were significantly improved in the RT-HIIT. Increases in body mass were smaller in RT-HIIT (ES = - 0.16) and AT-HIIT (ES = - 0.16) versus UC. RT-HIIT reported higher pressure-pain thresholds than UC (trapezius: ES = 0.46, gluteus: ES = 0.53) and AT-HIIT (trapezius: ES = 0.30). Sixteen weeks of RT-HIIT significantly improved muscle strength and reduced pain sensitivity. Both exercise programs were well tolerated and were equally efficient in preventing increases in body mass and in preventing declines in cardiorespiratory fitness. These results highlight the importance of implementing a combination of resistance and high-intensity interval training during chemotherapy for women with breast cancer.

White dwarf variability with gPhoton: pulsators

NASA Astrophysics Data System (ADS)

Tucker, Michael A.; Fleming, Scott W.; Pelisoli, Ingrid; Romero, Alejandra; Bell, Keaton J.; Kepler, S. O.; Caton, Daniel B.; Debes, John; Montgomery, Michael H.; Thompson, Susan E.; Koester, Detlev; Million, Chase; Shiao, Bernie

2018-04-01

We present results from a search for short time-scale white dwarf variability using gPhoton, a time-tagged data base of GALEX photon events and associated software package. We conducted a survey of 320 white dwarf stars in the McCook-Sion catalogue, inspecting each for photometric variability with particular emphasis on variability over time-scales less than ˜30 min. From that survey, we present the discovery of a new pulsating white dwarf: WD 2246-069. A Ca II K line is found in archival ESO spectra and an IR excess is seen in WISE W1 and W2 bands. Its independent modes are identified in follow-up optical photometry and used to model its interior structure. Additionally, we detect UV pulsations in four previously known pulsating ZZ Ceti-type (DAVs). Included in this group is the simultaneous fitting of the pulsations of WD 1401-147 in optical, near-ultraviolet and far-ultraviolet bands using nearly concurrent Whole Earth Telescope and GALEX data, providing observational insight into the wavelength dependence of white dwarf pulsation amplitudes.

The pharmacist Aggregate Demand Index to explain changing pharmacist demand over a ten-year period.

PubMed

Knapp, Katherine K; Shah, Bijal M; Barnett, Mitchell J

2010-12-15

To describe Aggregate Demand Index (ADI) trends from 1999-2010; to compare ADI time trends to concurrent data for US unemployment levels, US entry-level pharmacy graduates, and US retail prescription growth rate; and to determine which variables were significant predictors of ADI. Annual ADI data (dependent variable) were analyzed against annual unemployment rates, annual number of pharmacy graduates, and annual prescription growth rate (independent variables). ADI data trended toward lower demand levels for pharmacists since late 2006, paralleling the US economic downturn. National ADI data were most highly correlated with unemployment (p < 0.001), then graduates (p < 0.006), then prescription growth rate (p < 0.093). A hierarchical model with the 3 variables was significant (p = 0.019), but only unemployment was a significant ADI predictor. Unemployment and ADI also were significantly related at the regional, division, and state levels. The ADI is strongly linked to US unemployment rates. The relationship suggests that an improving economy might coincide with increased pharmacist demand. Predictable increases in future graduates and other factors support revisiting the modeling process as new data accumulate.

Substantial increase in concurrent droughts and heatwaves in the United States

PubMed Central

Mazdiyasni, Omid; AghaKouchak, Amir

2015-01-01

A combination of climate events (e.g., low precipitation and high temperatures) may cause a significant impact on the ecosystem and society, although individual events involved may not be severe extremes themselves. Analyzing historical changes in concurrent climate extremes is critical to preparing for and mitigating the negative effects of climatic change and variability. This study focuses on the changes in concurrences of heatwaves and meteorological droughts from 1960 to 2010. Despite an apparent hiatus in rising temperature and no significant trend in droughts, we show a substantial increase in concurrent droughts and heatwaves across most parts of the United States, and a statistically significant shift in the distribution of concurrent extremes. Although commonly used trend analysis methods do not show any trend in concurrent droughts and heatwaves, a unique statistical approach discussed in this study exhibits a statistically significant change in the distribution of the data. PMID:26324927

Substantial increase in concurrent droughts and heatwaves in the United States.

PubMed

Mazdiyasni, Omid; AghaKouchak, Amir

2015-09-15

A combination of climate events (e.g., low precipitation and high temperatures) may cause a significant impact on the ecosystem and society, although individual events involved may not be severe extremes themselves. Analyzing historical changes in concurrent climate extremes is critical to preparing for and mitigating the negative effects of climatic change and variability. This study focuses on the changes in concurrences of heatwaves and meteorological droughts from 1960 to 2010. Despite an apparent hiatus in rising temperature and no significant trend in droughts, we show a substantial increase in concurrent droughts and heatwaves across most parts of the United States, and a statistically significant shift in the distribution of concurrent extremes. Although commonly used trend analysis methods do not show any trend in concurrent droughts and heatwaves, a unique statistical approach discussed in this study exhibits a statistically significant change in the distribution of the data.

An interval logic for higher-level temporal reasoning

NASA Technical Reports Server (NTRS)

Schwartz, R. L.; Melliar-Smith, P. M.; Vogt, F. H.; Plaisted, D. A.

1983-01-01

Prior work explored temporal logics, based on classical modal logics, as a framework for specifying and reasoning about concurrent programs, distributed systems, and communications protocols, and reported on efforts using temporal reasoning primitives to express very high level abstract requirements that a program or system is to satisfy. Based on experience with those primitives, this report describes an Interval Logic that is more suitable for expressing such higher level temporal properties. The report provides a formal semantics for the Interval Logic, and several examples of its use. A description of decision procedures for the logic is also included.

Cortical Components of Reaction-Time during Perceptual Decisions in Humans.

PubMed

Dmochowski, Jacek P; Norcia, Anthony M

2015-01-01

The mechanisms of perceptual decision-making are frequently studied through measurements of reaction time (RT). Classical sequential-sampling models (SSMs) of decision-making posit RT as the sum of non-overlapping sensory, evidence accumulation, and motor delays. In contrast, recent empirical evidence hints at a continuous-flow paradigm in which multiple motor plans evolve concurrently with the accumulation of sensory evidence. Here we employ a trial-to-trial reliability-based component analysis of encephalographic data acquired during a random-dot motion task to directly image continuous flow in the human brain. We identify three topographically distinct neural sources whose dynamics exhibit contemporaneous ramping to time-of-response, with the rate and duration of ramping discriminating fast and slow responses. Only one of these sources, a parietal component, exhibits dependence on strength-of-evidence. The remaining two components possess topographies consistent with origins in the motor system, and their covariation with RT overlaps in time with the evidence accumulation process. After fitting the behavioral data to a popular SSM, we find that the model decision variable is more closely matched to the combined activity of the three components than to their individual activity. Our results emphasize the role of motor variability in shaping RT distributions on perceptual decision tasks, suggesting that physiologically plausible computational accounts of perceptual decision-making must model the concurrent nature of evidence accumulation and motor planning.

Delayed matching to sample and concurrent learning in nonamnesic humans with alcohol dependence.

PubMed

Bowden, S C; Benedikt, R; Ritter, A J

1992-05-01

Small samples of alcohol-dependent subjects who showed no clinical signs of Wernicke-Korsakoff syndrome were compared with nonalcohol-dependent controls on two animal memory tests which are performed poorly by human amnesics. Compared to the control subjects, the alcohol-dependent subjects' performance was impaired on a version of the delayed matching to sample task. On concurrent discrimination learning the overall group difference just failed to reach significance. The results are interpreted as suggesting that behavioural impairment may occur in alcohol-dependent subjects who are not clinically amnesic, and that the impairment is similar in type to that observed in cases of severe Wernicke-Korsakoff syndrome.

NEE and GPP dynamic evolution at two biomes in the upper Spanish plateau

NASA Astrophysics Data System (ADS)

Sánchez, María Luisa; Pardo, Nuria; Pérez, Isidro Alberto; García, Maria de los Angeles

2014-05-01

In order to assess the ability of dominant biomes to act as a CO2 sink, two eddy correlation stations close to each other in central Spain have been concurrently operational since March 2008 until the present. The land use of the first station, AC, is a rapeseed rotating crop consisting of annual rotation of non-irrigated rapeseed, barley, peas, rye, and sunflower, respectively. The land use of the second, CIBA, is a mixture of open shrubs/crops, with open shrubs being markedly dominant. The period of measurements covered variable general meteorological conditions. 2009 and 2012 were dominated by drought, whereas 2010 was the rainiest year. Annual rainfall during 2008 and 2009 was close to the historical averaged annual means. This paper presents the dynamic evolution of NEE-8d and GPP-8d observed at the AC station over five years and compares the results with those concurrently observed at the CIBA station. GGP 8-d estimates at both stations were determined using a Light Use Efficiency Model, LUE. Input data for the LUE model were the FPAR 8-d products supplied by MODIS, PAR in situ measurements, and a scalar f, varying between 0 and 1, to take account of the reduction in maximum PAR conversion efficiency, ɛ0, under limiting environmental conditions. f values were assumed to be dependent on air temperature and evaporative fraction, EF, which was considered a proxy of soil moisture. ɛ0, a key parameter, which depends on land use types, was derived through the results of a linear regression fit between the GPP 8-d eddy covariance composites observed and the LUE concurrent 8-d model estimates. Over the five-year study period, both biomes behaved as CO2 sinks. However, the ratio of the NEE-8d total accumulated at AC and CIBA, respectively, was close to a factor two, revealing the effectiveness of the studied crops as CO2 sinks. On an annual basis, accumulated NEE-8d exhibited major variability in both biomes. At CIBA, the results were largely dominated by the prevailing annual rainfall, whereas at AC results were also strongly dependent on type of crops. Similar results were obtained for GPP 8-d. The LUE model fitted observed GPP 8-d satisfactorily at both biomes (R2 >86%). The ɛ0value in the rotating crop station, AC, was approximately 1.7 higher than at the open shrub station, CIBA. Acknowledgements This paper has been funded by the Spanish MICINN-MINECO and ERDF funds.

Effect of Temperature on Heart Rate Variability in Neonatal ICU Patients With Hypoxic-Ischemic Encephalopathy.

PubMed

Massaro, An N; Campbell, Heather E; Metzler, Marina; Al-Shargabi, Tareq; Wang, Yunfei; du Plessis, Adre; Govindan, Rathinaswamy B

2017-04-01

To determine whether measures of heart rate variability are related to changes in temperature during rewarming after therapeutic hypothermia for hypoxic-ischemic encephalopathy. Prospective observational study. Level 4 neonatal ICU in a free-standing academic children's hospital. Forty-four infants with moderate to severe hypoxic-ischemic encephalopathy treated with therapeutic hypothermia. Continuous electrocardiogram data from 2 hours prior to rewarming through 2 hours after completion of rewarming (up to 10 hr) were analyzed. Median beat-to-beat interval and measures of heart rate variability were quantified including beat-to-beat interval SD, low and high frequency relative spectral power, detrended fluctuation analysis short and long α exponents (αS and αL), and root mean square short and long time scales. The relationships between heart rate variability measures and esophageal/axillary temperatures were evaluated. Heart rate variability measures low frequency, αS, and root mean square short and long time scales were negatively associated, whereas αL was positively associated, with temperature (p < 0.01). These findings signify an overall decrease in heart rate variability as temperature increased toward normothermia. Measures of heart rate variability are temperature dependent in the range of therapeutic hypothermia to normothermia. Core body temperature needs to be considered when evaluating heart rate variability metrics as potential physiologic biomarkers of illness severity in hypoxic-ischemic encephalopathy infants undergoing therapeutic hypothermia.

Concurrent credit portfolio losses

PubMed Central

Sicking, Joachim; Schäfer, Rudi

2018-01-01

We consider the problem of concurrent portfolio losses in two non-overlapping credit portfolios. In order to explore the full statistical dependence structure of such portfolio losses, we estimate their empirical pairwise copulas. Instead of a Gaussian dependence, we typically find a strong asymmetry in the copulas. Concurrent large portfolio losses are much more likely than small ones. Studying the dependences of these losses as a function of portfolio size, we moreover reveal that not only large portfolios of thousands of contracts, but also medium-sized and small ones with only a few dozens of contracts exhibit notable portfolio loss correlations. Anticipated idiosyncratic effects turn out to be negligible. These are troublesome insights not only for investors in structured fixed-income products, but particularly for the stability of the financial sector. JEL codes: C32, F34, G21, G32, H81. PMID:29425246

Concurrent credit portfolio losses.

PubMed

Sicking, Joachim; Guhr, Thomas; Schäfer, Rudi

2018-01-01

We consider the problem of concurrent portfolio losses in two non-overlapping credit portfolios. In order to explore the full statistical dependence structure of such portfolio losses, we estimate their empirical pairwise copulas. Instead of a Gaussian dependence, we typically find a strong asymmetry in the copulas. Concurrent large portfolio losses are much more likely than small ones. Studying the dependences of these losses as a function of portfolio size, we moreover reveal that not only large portfolios of thousands of contracts, but also medium-sized and small ones with only a few dozens of contracts exhibit notable portfolio loss correlations. Anticipated idiosyncratic effects turn out to be negligible. These are troublesome insights not only for investors in structured fixed-income products, but particularly for the stability of the financial sector. JEL codes: C32, F34, G21, G32, H81.

Combinations of Response-Dependent and Response-Independent Schedule-Correlated Stimulus Presentation in an Observing Procedure

ERIC Educational Resources Information Center

DeFulio, Anthony; Hackenberg, Timothy D.

2008-01-01

Pigeons pecked a response key on a variable-interval (VI) schedule, in which responses produced food every 40 s, on average. These VI periods, or components, alternated in irregular fashion with extinction components in which food was unavailable. Pecks on a second (observing) key briefly produced exteroceptive stimuli (houselight flashes)…

Serial alterations in digital hemodynamics and endothelin-1 immunoreactivity, platelet-neutrophil aggregation, and concentrations of nitric oxide, insulin, and glucose in blood obtained from horses following carbohydrate overload.

PubMed

Eades, Susan C; Stokes, Ashley M; Johnson, Philip J; LeBlanc, Casey J; Ganjam, Venkataseshu K; Buff, Preston R; Moore, Rustin M

2007-01-01

To quantify changes in endothelium-derived factors and relate those changes to various aspects of digital hemodynamics during the prodromal stages of carbohydrate overload (CHO)-induced laminitis in horses. 20 adult horses without abnormalities of the digit. Digital and jugular venous blood samples were collected at 1-hour intervals (for assessment of endothelin-1 [ET-1] immunoreactivity and measurement of glucose, insulin, and nitric oxide [NO] concentrations) or 4-hour intervals (CBC and platelet-neutrophil aggregate assessment) for 8 hours or 16 hours after induction of CHO-associated laminitis in horses treated with an ET-1 antagonist. Effects of treatment, collection site, and time and the random effects of horse on each variable were analyzed by use of a repeated-measures model. Where treatment and collection site had no significant effect, data were combined. Compared with baseline values, CHO resulted in changes in several variables, including a significant increase from baseline in digital blood ET-like immunoreactivity at 11 hours; digital blood ET-like immunoreactivity was significantly greater than that in jugular venous blood at 8, 9, 11, and 12 hours. Digital and jugular venous blood concentrations of glucose increased from baseline significantly at 3, 4, and 5 hours; insulin concentration increased significantly at 5 hours; and the number of platelet-neutrophil aggregates increased significantly at 12 hours. In horses, concurrent increases in venous blood ET-1 immunoreactivity, insulin and glucose concentrations, and platelet-neutrophil aggregates support a role of endothelial dysfunction in the pathogenesis of CHO-induced laminitis.

Advanced statistics: linear regression, part II: multiple linear regression.

PubMed

Marill, Keith A

2004-01-01

The applications of simple linear regression in medical research are limited, because in most situations, there are multiple relevant predictor variables. Univariate statistical techniques such as simple linear regression use a single predictor variable, and they often may be mathematically correct but clinically misleading. Multiple linear regression is a mathematical technique used to model the relationship between multiple independent predictor variables and a single dependent outcome variable. It is used in medical research to model observational data, as well as in diagnostic and therapeutic studies in which the outcome is dependent on more than one factor. Although the technique generally is limited to data that can be expressed with a linear function, it benefits from a well-developed mathematical framework that yields unique solutions and exact confidence intervals for regression coefficients. Building on Part I of this series, this article acquaints the reader with some of the important concepts in multiple regression analysis. These include multicollinearity, interaction effects, and an expansion of the discussion of inference testing, leverage, and variable transformations to multivariate models. Examples from the first article in this series are expanded on using a primarily graphic, rather than mathematical, approach. The importance of the relationships among the predictor variables and the dependence of the multivariate model coefficients on the choice of these variables are stressed. Finally, concepts in regression model building are discussed.

The Effect of Two Different Concurrent Training Programs on Strength and Power Gains in Highly-Trained Individuals

PubMed Central

Petré, Henrik; Löfving, Pontus; Psilander, Niklas

2018-01-01

The effects of concurrent strength and endurance training have been well studied in untrained and moderately-trained individuals. However, studies examining these effects in individuals with a long history of resistance training (RT) are lacking. Additionally, few studies have examined how strength and power are affected when different types of endurance training are added to an RT protocol. The purpose of the present study was to compare the effects of concurrent training incorporating either low-volume, high-intensity interval training (HIIT, 8-24 Tabata intervals at ~150% of VO2max) or high-volume, medium-intensity continuous endurance training (CT, 40-80 min at 70% of VO2max), on the strength and power of highly-trained individuals. Sixteen highly-trained ice-hockey and rugby players were divided into two groups that underwent either CT (n = 8) or HIIT (n = 8) in parallel with RT (2-6 sets of heavy parallel squats, > 80% of 1RM) during a 6-week period (3 sessions/wk). Parallel squat performance improved after both RT + CT and RT + HIIT (12 ± 8% and 14 ± 10% respectively, p < 0.01), with no difference between the groups. However, aerobic power (VO2max) only improved after RT + HIIT (4 ± 3%, p < 0.01). We conclude that strength gains can be obtained after both RT + CT and RT + HIIT in athletes with a prior history of RT. This indicates that the volume and/or intensity of the endurance training does not influence the magnitude of strength improvements during short periods of concurrent training, at least for highly-trained individuals when the endurance training is performed after RT. However, since VO2max improved only after RT + HIIT and this is a time efficient protocol, we recommend this type of concurrent endurance training. Key points Lower body maximal strength is improved after concurrent strength and endurance training in highly trained individuals. The magnitude of this strength improvement is not influenced by the type of endurance training, i.e. HIIT or CT. HIIT improves VO2max and is more time efficient than CT. HIIT is recommended to athletes when concurrently training for strength and endurance. PMID:29769816

VARIABLE TIME-INTERVAL GENERATOR

DOEpatents

Gross, J.E.

1959-10-31

This patent relates to a pulse generator and more particularly to a time interval generator wherein the time interval between pulses is precisely determined. The variable time generator comprises two oscillators with one having a variable frequency output and the other a fixed frequency output. A frequency divider is connected to the variable oscillator for dividing its frequency by a selected factor and a counter is used for counting the periods of the fixed oscillator occurring during a cycle of the divided frequency of the variable oscillator. This defines the period of the variable oscillator in terms of that of the fixed oscillator. A circuit is provided for selecting as a time interval a predetermined number of periods of the variable oscillator. The output of the generator consists of a first pulse produced by a trigger circuit at the start of the time interval and a second pulse marking the end of the time interval produced by the same trigger circuit.

Hydroclimate variability in Scandinavia over the last millennium - insights from a climate model-proxy data comparison

NASA Astrophysics Data System (ADS)

Seftigen, Kristina; Goosse, Hugues; Klein, Francois; Chen, Deliang

2017-12-01

The integration of climate proxy information with general circulation model (GCM) results offers considerable potential for deriving greater understanding of the mechanisms underlying climate variability, as well as unique opportunities for out-of-sample evaluations of model performance. In this study, we combine insights from a new tree-ring hydroclimate reconstruction from Scandinavia with projections from a suite of forced transient simulations of the last millennium and historical intervals from the CMIP5 and PMIP3 archives. Model simulations and proxy reconstruction data are found to broadly agree on the modes of atmospheric variability that produce droughts-pluvials in the region. Despite these dynamical similarities, large differences between simulated and reconstructed hydroclimate time series remain. We find that the GCM-simulated multi-decadal and/or longer hydroclimate variability is systematically smaller than the proxy-based estimates, whereas the dominance of GCM-simulated high-frequency components of variability is not reflected in the proxy record. Furthermore, the paleoclimate evidence indicates in-phase coherencies between regional hydroclimate and temperature on decadal timescales, i.e., sustained wet periods have often been concurrent with warm periods and vice versa. The CMIP5-PMIP3 archive suggests, however, out-of-phase coherencies between the two variables in the last millennium. The lack of adequate understanding of mechanisms linking temperature and moisture supply on longer timescales has serious implications for attribution and prediction of regional hydroclimate changes. Our findings stress the need for further paleoclimate data-model intercomparison efforts to expand our understanding of the dynamics of hydroclimate variability and change, to enhance our ability to evaluate climate models, and to provide a more comprehensive view of future drought and pluvial risks.

Concurrent bariatric operations and association with perioperative outcomes: registry based cohort study.

PubMed

Liu, Jason B; Ban, Kristen A; Berian, Julia R; Hutter, Matthew M; Huffman, Kristopher M; Liu, Yaoming; Hoyt, David B; Hall, Bruce L; Ko, Clifford Y

2017-09-26

Objective  To determine whether perioperative outcomes differ between patients undergoing concurrent compared with non-concurrent bariatric operations in the USA. Design  Retrospective, propensity score matched cohort study. Setting  Hospitals in the US accredited by the American College of Surgeons' metabolic and bariatric surgery accreditation and quality improvement program. Participants  513 167 patients undergoing bariatric operations between 1 January 2014 and 31 December 2016. Main outcome measures  The primary outcome measure was a composite of 30 day death, morbidity, readmission, reoperation, anastomotic or staple line leak, and bleeding events. Operative duration and lengths of stay were also assessed. Operations were defined as concurrent if they overlapped by 60 or more minutes or in their entirety. Results  In this study of 513 167 operations, 739 (29.5%) surgeons at 483 (57.8%) hospitals performed 6087 (1.2%) concurrent operations. The most frequently performed concurrent bariatric operations were sleeve gastrectomy (n=3250, 53.4%) and Roux-en-Y gastric bypass (n=1601, 26.3%). Concurrent operations were more often performed at large academic medical centers with higher operative volumes and numbers of trainees and by higher volume surgeons. Compared with non-concurrent operations, concurrent operations lasted a median of 34 minutes longer (P<0.001) and resulted in 0.3 days longer average length of stay (P<0.001). Perioperative adverse events were not observed to more likely occur in concurrent compared with non-concurrent operations (7.5% v 7.4%; relative risk 1.02, 95% confidence interval 0.90 to 1.15; P=0.84). Conclusions  Concurrent bariatric operations occurred infrequently, but when they did, there was no observable increased risk for adverse perioperative outcomes compared with non-concurrent operations. These results, however, do not argue against improved and more meaningful disclosure of concurrent surgery practices. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

The effect of scopolamine on matching behavior and the estimation of relative reward magnitude.

PubMed

Leon, Matthew I; Rodriguez-Barrera, Vanessa; Amaya, Aldo

2017-10-01

We investigated the behavioral effects of scopolamine on rats that bar pressed for trains of electrically stimulating pulses under concurrent variable interval schedules of reward. For the first half of the session (30 min) a 1:4 ratio in the programmed number of stimulation trains delivered at each option was in effect. At the start of the second half of the session, an unsignaled reversal in the relative train number (4:1) occurred. We tracked the relative magnitude of reward estimated for each contiguous pair of reinforced visits to competing options. Scopolamine hydrobromide led to a reduction in the relative magnitude of reward. A similar result was obtained in a follow-up test in which relative magnitude was manipulated by varying the pulse frequency of stimulation, while equating the train number at each option. The effect of scopolamine hydrobromide could not be attributed to undermatching, side bias, nor to an effect of scopolamine on the reward integration process. When the same rats were treated with scopolamine methylbromide, no effects on matching behavior were observed. Our results suggest a cholinergic basis for the computation of choice variables related to matching behavior. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Radio and X-ray variability of the nucleus of Centaurus A /NGC 5128/

NASA Technical Reports Server (NTRS)

Beall, J. H.; Rose, W. K.; Graf, W.; Price, K. M.; Dent, W. A.; Hobbs, R. W.; Dennis, B. R.; Crannell, C. J.; Conklin, E. K.; Ulich, B. L.

1978-01-01

Centaurus A (NGC 5128) has been observed at radio frequencies of 10.7, 31.4, 85.2, and 89 GHz and at X-ray energies greater than 20 keV. These observations, together with results reported by other workers, are interpreted in terms of models of the nucleus of this radio galaxy. The radio observations cover the period from 1973 through early 1977. The X-ray observations cover two 10-day intervals, one in July and August (1975) and the other in July and August 1976. The source exhibits significant variability in all the observed radio frequencies. The observed radio and X-ray intensities show some concurrent variations but do not track one another throughout the observations. A model of the source in which X-rays are produced by inverse Compton scattering of blackbody photons by relativistic electrons is proposed to explain these observations. The observed variations in the electromagnetic spectrum are shown to be consistent with adiabatic expansion of a trapped plasma in conjunction with turbulent accelerations of the relativistic electrons. Upper limits obtained with the model indicate that there may be sufficient energy available in the nucleus to form radio lobes with the same total energy as those already present.

Shoulder pain and time dependent structure in wheelchair propulsion variability

PubMed Central

Jayaraman, Chandrasekaran; Moon, Yaejin; Sosnoff, Jacob J.

2016-01-01

Manual wheelchair propulsion places considerable repetitive mechanical strain on the upper limbs leading to shoulder injury and pain. While recent research indicates that the amount of variability in wheelchair propulsion and shoulder pain may be related. There has been minimal inquiry into the fluctuation over time (i.e. time-dependent structure) in wheelchair propulsion variability. Consequently the purpose of this investigation was to examine if the time-dependent structure in the wheelchair propulsion parameters are related to shoulder pain. 27 experienced wheelchair users manually propelled their own wheelchair fitted with a SMARTWheel on a roller at 1.1 m/s for 3 minutes. Time-dependent structure of cycle-to-cycle fluctuations in contact angle and inter push time interval was quantified using sample entropy (SampEn) and compared between the groups with/without shoulder pain using non-parametric statistics. Overall findings were, (1) variability observed in contact angle fluctuations during manual wheelchair propulsion is structured (Z=3.15;p<0.05), (2) individuals with shoulder pain exhibited higher SampEn magnitude for contact angle during wheelchair propulsion than those without pain (χ2(1)=6.12;p<0.05); and (3) SampEn of contact angle correlated significantly with self-reported shoulder pain (rs (WUSPI) =0.41;rs (VAS)=0.56;p<0.05). It was concluded that the time-dependent structure in wheelchair propulsion may provide novel information for tracking and monitoring shoulder pain. PMID:27134151

A Reduced Form Model for Ozone Based on Two Decades of ...

EPA Pesticide Factsheets

A Reduced Form Model (RFM) is a mathematical relationship between the inputs and outputs of an air quality model, permitting estimation of additional modeling without costly new regional-scale simulations. A 21-year Community Multiscale Air Quality (CMAQ) simulation for the continental United States provided the basis for the RFM developed in this study. Predictors included the principal component scores (PCS) of emissions and meteorological variables, while the predictand was the monthly mean of daily maximum 8-hour CMAQ ozone for the ozone season at each model grid. The PCS form an orthogonal basis for RFM inputs. A few PCS incorporate most of the variability of emissions and meteorology, thereby reducing the dimensionality of the source-receptor problem. Stochastic kriging was used to estimate the model. The RFM was used to separate the effects of emissions and meteorology on ozone concentrations. by running the RFM with emissions constant (ozone dependent on meteorology), or constant meteorology (ozone dependent on emissions). Years with ozone-conducive meteorology were identified, and meteorological variables best explaining meteorology-dependent ozone were identified. Meteorology accounted for 19% to 55% of ozone variability in the eastern US, and 39% to 92% in the western US. Temporal trends estimated for original CMAQ ozone data and emission-dependent ozone were mostly negative, but the confidence intervals for emission-dependent ozone are much

Effect of 8 weeks of concurrent plyometric and running training on spatiotemporal and physiological variables of novice runners.

PubMed

Gómez-Molina, Josué; Ogueta-Alday, Ana; Camara, Jesus; Stickley, Christopher; García-López, Juan

2018-03-01

Concurrent plyometric and running training has the potential to improve running economy (RE) and performance through increasing muscle strength and power, but the possible effect on spatiotemporal parameters of running has not been studied yet. The aim of this study was to compare the effect of 8 weeks of concurrent plyometric and running training on spatiotemporal parameters and physiological variables of novice runners. Twenty-five male participants were randomly assigned into two training groups; running group (RG) (n = 11) and running + plyometric group (RPG) (n = 14). Both groups performed 8 weeks of running training programme, and only the RPG performed a concurrent plyometric training programme (two sessions per week). Anthropometric, physiological (VO 2max , heart rate and RE) and spatiotemporal variables (contact and flight times, step rate and length) were registered before and after the intervention. In comparison to RG, the RPG reduced step rate and increased flight times at the same running speeds (P < .05) while contact times remained constant. Significant increases in pre- and post-training (P < .05) were found in RPG for squat jump and 5 bound test, while RG remained unchanged. Peak speed, ventilatory threshold (VT) speed and respiratory compensation threshold (RCT) speed increased (P < .05) for both groups, although peak speed and VO 2max increased more in the RPG than in the RG. In conclusion, concurrent plyometric and running training entails a reduction in step rate, as well as increases in VT speed, RCT speed, peak speed and VO 2max . Athletes could benefit from plyometric training in order to improve their strength, which would contribute to them attaining higher running speeds.

Analysis of pelvic rotation on the standard hip ventrodorsal extended radiographic view.

PubMed

Martins, João; Colaço, Bruno J; Ferreira, António J; Ginja, Mário M

2016-01-01

To study the symmetry of the iliac horizontal diameter (IHD) maximum obturator foramen width (OFW), ischiatic femoral overlap (IFO), pelvic horizontal radius (PHR), femoral head diameter (FHD), and obturator foramen area (OFA) parameters in the normal hip extended radiographic view and to evaluate the correlation of pelvic rotation with the magnitude of asymmetry of these parameters. Nine canine cadavers from adult, large and giant breeds were radiographed in standard hip extended views and with 2°, 4° and 6° degrees of rotation. The variables IHD, OFW, IFO, PHR, FHD, and OFA were analysed in radiographs. The IHD measurements exhibited repeatability, bilateral symmetry and 95% of confidence interval of asymmetry in different pelvic rotations without superposition (p <0.05); OFW and IFO exhibited repeatability, bilateral symmetry and a small superposition in 95% of confidence interval of asymmetry according different pelvic rotations; PHR, FHD and OFA exhibited repeatability, bilateral symmetry and unacceptable superposition in 95% of confidence interval of asymmetry depending on pelvic rotation. The IHD is the recommended variable and OFW is an acceptable variable in order to evaluate slight pelvic rotation. The data may be used in qualitative analyses of hip extended radiographic views. In the future, complementary studies should be performed to evaluate the impact of degree of pelvic rotation on the hip dysplasia score.

The Effect of Two Different Concurrent Training Programs on Strength and Power Gains in Highly-Trained Individuals.

PubMed

Petré, Henrik; Löfving, Pontus; Psilander, Niklas

2018-06-01

The effects of concurrent strength and endurance training have been well studied in untrained and moderately-trained individuals. However, studies examining these effects in individuals with a long history of resistance training (RT) are lacking. Additionally, few studies have examined how strength and power are affected when different types of endurance training are added to an RT protocol. The purpose of the present study was to compare the effects of concurrent training incorporating either low-volume, high-intensity interval training (HIIT, 8-24 Tabata intervals at ~150% of VO 2max ) or high-volume, medium-intensity continuous endurance training (CT, 40-80 min at 70% of VO 2max ), on the strength and power of highly-trained individuals. Sixteen highly-trained ice-hockey and rugby players were divided into two groups that underwent either CT (n = 8) or HIIT (n = 8) in parallel with RT (2-6 sets of heavy parallel squats, > 80% of 1RM) during a 6-week period (3 sessions/wk). Parallel squat performance improved after both RT + CT and RT + HIIT (12 ± 8% and 14 ± 10% respectively, p < 0.01), with no difference between the groups. However, aerobic power (VO 2max ) only improved after RT + HIIT (4 ± 3%, p < 0.01). We conclude that strength gains can be obtained after both RT + CT and RT + HIIT in athletes with a prior history of RT. This indicates that the volume and/or intensity of the endurance training does not influence the magnitude of strength improvements during short periods of concurrent training, at least for highly-trained individuals when the endurance training is performed after RT. However, since VO 2max improved only after RT + HIIT and this is a time efficient protocol, we recommend this type of concurrent endurance training.

Digoxin and bepridil: pharmacokinetic and pharmacodynamic interactions.

PubMed

Belz, G G; Wistuba, S; Matthews, J H

1986-01-01

The influence of bepridil on steady-state serum digoxin concentrations (SDCs) and the pharmacodynamic actions of both drugs were tested in 48 healthy subjects in a randomized, double-blind study. Subjects were assigned to one of two groups of 24 subjects each: One group received placebo 1, while the other received digoxin, 0.375 mg/day, loaded with doubled doses on days 1 and 2, for 14 days. After 7 days the groups were subdivided into four groups of 12 subjects each and received concurrent dosing of digoxin with either placebo 2 or bepridil, 300 mg/day, loaded with 900 mg on day 8. Mean (+/- SD) SDCs rose during concurrent bepridil dosing from 0.93 +/- 0.22 to 1.25 +/- 0.25 ng/ml (P less than 0.001). Noninvasive cardiovascular parameters from ECG, systolic time intervals, and electrical impedance cardiography were not influenced by the placebos. Digoxin and bepridil reduced heart rate and prolonged the PQ interval because of negative chronotropic and dromotropic properties. Positive inotropism from digoxin shortened the corrected electromechanical systole (QS2c) and the preejection period and increased impedance cardiography [(dZ/dt)/RZ index]; the opposite effects occurred after bepridil, indicating negative inotropism. The QT interval corrected for heart rate (QTc) showed a similar pattern of changes, as did QS2c for each drug. Concurrent dosing of both drugs resulted in an addition of their chronotropic effects, whereas the dromotropic effects of each drug alone was not intensified. The strengthened digoxin effect from the increased SDC diminished the negative inotropic effect of bepridil. Overall, drug coadministration resulted in a nearly unchanged digoxin-induced positive inotropism.(ABSTRACT TRUNCATED AT 250 WORDS)

Incorporating Duration Information in Activity Recognition

NASA Astrophysics Data System (ADS)

Chaurasia, Priyanka; Scotney, Bryan; McClean, Sally; Zhang, Shuai; Nugent, Chris

Activity recognition has become a key issue in smart home environments. The problem involves learning high level activities from low level sensor data. Activity recognition can depend on several variables; one such variable is duration of engagement with sensorised items or duration of intervals between sensor activations that can provide useful information about personal behaviour. In this paper a probabilistic learning algorithm is proposed that incorporates episode, time and duration information to determine inhabitant identity and the activity being undertaken from low level sensor data. Our results verify that incorporating duration information consistently improves the accuracy.

Comparing Classic and Interval Analytical Hierarchy Process Methodologies for Measuring Area-Level Deprivation to Analyze Health Inequalities.

PubMed

Cabrera-Barona, Pablo; Ghorbanzadeh, Omid

2018-01-16

Deprivation indices are useful measures to study health inequalities. Different techniques are commonly applied to construct deprivation indices, including multi-criteria decision methods such as the analytical hierarchy process (AHP). The multi-criteria deprivation index for the city of Quito is an index in which indicators are weighted by applying the AHP. In this research, a variation of this index is introduced that is calculated using interval AHP methodology. Both indices are compared by applying logistic generalized linear models and multilevel models, considering self-reported health as the dependent variable and deprivation and self-reported quality of life as the independent variables. The obtained results show that the multi-criteria deprivation index for the city of Quito is a meaningful measure to assess neighborhood effects on self-reported health and that the alternative deprivation index using the interval AHP methodology more thoroughly represents the local knowledge of experts and stakeholders. These differences could support decision makers in improving health planning and in tackling health inequalities in more deprived areas.

Comparing Classic and Interval Analytical Hierarchy Process Methodologies for Measuring Area-Level Deprivation to Analyze Health Inequalities

PubMed Central

Cabrera-Barona, Pablo

2018-01-01

Deprivation indices are useful measures to study health inequalities. Different techniques are commonly applied to construct deprivation indices, including multi-criteria decision methods such as the analytical hierarchy process (AHP). The multi-criteria deprivation index for the city of Quito is an index in which indicators are weighted by applying the AHP. In this research, a variation of this index is introduced that is calculated using interval AHP methodology. Both indices are compared by applying logistic generalized linear models and multilevel models, considering self-reported health as the dependent variable and deprivation and self-reported quality of life as the independent variables. The obtained results show that the multi-criteria deprivation index for the city of Quito is a meaningful measure to assess neighborhood effects on self-reported health and that the alternative deprivation index using the interval AHP methodology more thoroughly represents the local knowledge of experts and stakeholders. These differences could support decision makers in improving health planning and in tackling health inequalities in more deprived areas. PMID:29337915

Earthquake stress drop and laboratory-inferred interseismic strength recovery

USGS Publications Warehouse

Beeler, N.M.; Hickman, S.H.; Wong, T.-F.

2001-01-01

We determine the scaling relationships between earthquake stress drop and recurrence interval tr that are implied by laboratory-measured fault strength. We assume that repeating earthquakes can be simulated by stick-slip sliding using a spring and slider block model. Simulations with static/kinetic strength, time-dependent strength, and rate- and state-variable-dependent strength indicate that the relationship between loading velocity and recurrence interval can be adequately described by the power law VL ??? trn, where n=-1. Deviations from n=-1 arise from second order effects on strength, with n>-1 corresponding to apparent time-dependent strengthening and n<-1 corresponding to weakening. Simulations with rate and state-variable equations show that dynamic shear stress drop ????d scales with recurrence as d????d/dlntr ??? ??e(b-a), where ??e is the effective normal stress, ??=??/??e, and (a-b)=d??ss/dlnV is the steady-state slip rate dependence of strength. In addition, accounting for seismic energy radiation, we suggest that the static shear stress drop ????s scales as d????s/dlntr ??? ??e(1+??)(b-a), where ?? is the fractional overshoot. The variation of ????s with lntr for earthquake stress drops is somewhat larger than implied by room temperature laboratory values of ?? and b-a. However, the uncertainty associated with the seismic data is large and the discrepancy between the seismic observations and the rate of strengthening predicted by room temperature experiments is less than an order of magnitude. Copyright 2001 by the American Geophysical Union.

Early to middle Miocene climate evolution: benthic oxygen and carbon isotope records from Walvis Ridge Site 1264.

NASA Astrophysics Data System (ADS)

Lourens, L. J.; Beddow, H.; Liebrand, D.; Schrader, C.; Hilgen, F. J.

2016-12-01

Across the early to middle Miocene, high-resolution records from the Pacific Ocean indicate a dynamic climate system, encompassing a 2 Myr global warming event from 17 Ma to 14.7 Ma, followed by a major Cenozoic cooling step at 14.2 Ma -13.8 Ma. Currently, no high-resolution benthic record from the Atlantic Ocean exists covering both events, limiting global coverage of this intriguing period in Cenozoic climate evolution. Here, we present the first early to middle Miocene high-resolution from the Atlantic basin. These records, from Site 1264 on the Walvis Ridge, span a 5.5 Myr long interval (13.24-18.90 ma) in high temporal resolution ( 4 kyr) and are tuned to eccentricity. The d18O record shows a sudden (high-latitude) warming/deglaciation on Antarctica at 17.1 Ma, a rapid cooling/glaciation of Antarctica at 13.8 Ma, and high-amplitude ( 1‰) variability on astronomical time-scales throughout this interval. Together with other records from this time interval located in the Pacific, which show similar features, the data strongly suggests a highly dynamic global climate system. We find cooling steps in d18O at 14.7, 14.2 and 13.8 Ma, suggesting concurrent cooling in the Pacific and Atlantic deep waters during the MMCT. The benthic foraminiferal stable isotope records reveal that the dominant astronomical frequencies present at ODP Site 1264 during the early to middle Miocene interval are the 405 kyr and 110 kyr eccentricity periodicities. This is a contrast to other early to middle Miocene records from drill-sites in the Pacific and South China Sea, which show a strong expression of obliquity in particular between 14.2 and 14.7 Ma.

Validity of clinical outcome measures to evaluate ankle range of motion during the weight-bearing lunge test.

PubMed

Hall, Emily A; Docherty, Carrie L

2017-07-01

To determine the concurrent validity of standard clinical outcome measures compared to laboratory outcome measure while performing the weight-bearing lunge test (WBLT). Cross-sectional study. Fifty participants performed the WBLT to determine dorsiflexion ROM using four different measurement techniques: dorsiflexion angle with digital inclinometer at 15cm distal to the tibial tuberosity (°), dorsiflexion angle with inclinometer at tibial tuberosity (°), maximum lunge distance (cm), and dorsiflexion angle using a 2D motion capture system (°). Outcome measures were recorded concurrently during each trial. To establish concurrent validity, Pearson product-moment correlation coefficients (r) were conducted, comparing each dependent variable to the 2D motion capture analysis (identified as the reference standard). A higher correlation indicates strong concurrent validity. There was a high correlation between each measurement technique and the reference standard. Specifically the correlation between the inclinometer placement at 15cm below the tibial tuberosity (44.9°±5.5°) and the motion capture angle (27.0°±6.0°) was r=0.76 (p=0.001), between the inclinometer placement at the tibial tuberosity angle (39.0°±4.6°) and the motion capture angle was r=0.71 (p=0.001), and between the distance from the wall clinical measure (10.3±3.0cm) to the motion capture angle was r=0.74 (p=0.001). This study determined that the clinical measures used during the WBLT have a high correlation with the reference standard for assessing dorsiflexion range of motion. Therefore, obtaining maximum lunge distance and inclinometer angles are both valid assessments during the weight-bearing lunge test. Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Choice and conditioned reinforcement.

PubMed Central

Fantino, E; Freed, D; Preston, R A; Williams, W A

1991-01-01

A potential weakness of one formulation of delay-reduction theory is its failure to include a term for rate of conditioned reinforcement, that is, the rate at which the terminal-link stimuli occur in concurrent-chains schedules. The present studies assessed whether or not rate of conditioned reinforcement has an independent effect upon choice. Pigeons responded on either modified concurrent-chains schedules or on comparable concurrent-tandem schedules. The initial link was shortened on only one of two concurrent-chains schedules and on only one of two corresponding concurrent-tandem schedules. This manipulation increased rate of conditioned reinforcement sharply in the chain but not in the tandem schedule. According to a formulation of delay-reduction theory, when the outcomes chosen (the terminal links) are equal, as in Experiment 1, choice should depend only on rate of primary reinforcement; thus, choice should be equivalent for the tandem and chain schedules despite a large difference in rate of conditioned reinforcement. When the outcomes chosen are unequal, however, as in Experiment 2, choice should depend upon both rate of primary reinforcement and relative signaled delay reduction; thus, larger preferences should occur in the chain than in the tandem schedules. These predictions were confirmed, suggesting that increasing the rate of conditioned reinforcement on concurrent-chains schedules may have no independent effect on choice. PMID:2037826

Virtual Active Touch Using Randomly Patterned Intracortical Microstimulation

PubMed Central

O’Doherty, Joseph E.; Lebedev, Mikhail A.; Li, Zheng; Nicolelis, Miguel A.L.

2012-01-01

Intracortical microstimulation (ICMS) has promise as a means for delivering somatosensory feedback in neuroprosthetic systems. Various tactile sensations could be encoded by temporal, spatial, or spatiotemporal patterns of ICMS. However, the applicability of temporal patterns of ICMS to artificial tactile sensation during active exploration is unknown, as is the minimum discriminable difference between temporally modulated ICMS patterns. We trained rhesus monkeys in an active exploration task in which they discriminated periodic pulse-trains of ICMS (200 Hz bursts at a 10 Hz secondary frequency) from pulse trains with the same average pulse rate, but distorted periodicity (200 Hz bursts at a variable instantaneous secondary frequency). The statistics of the aperiodic pulse trains were drawn from a gamma distribution with mean inter-burst intervals equal to those of the periodic pulse trains. The monkeys distinguished periodic pulse trains from aperiodic pulse trains with coefficients of variation 0.25 or greater. Reconstruction of movement kinematics, extracted from the activity of neuronal populations recorded in the sensorimotor cortex concurrent with the delivery of ICMS feedback, improved when the recording intervals affected by ICMS artifacts were removed from analysis. These results add to the growing evidence that temporally patterned ICMS can be used to simulate a tactile sense for neuroprosthetic devices. PMID:22207642

The evaluation of β-adrenoceptor blocking agents in patients with COPD and congestive heart failure: a nationwide study

PubMed Central

Lin, Tien-Yu; Huang, Yaw-Bin; Chen, Chung-Yu

2017-01-01

Objective β-Blockers are safe and improve survival in patients with both congestive heart failure (CHF) and COPD. However, the superiority of different types of β-blockers is still unclear among patients with CHF and COPD. The association between β-blockers and CHF exacerbation as well as COPD exacerbation remains unclear. The objective of this study was to compare the outcome of different β-blockers in patients with concurrent CHF and COPD. Patients and methods We used the National Health Insurance Research Database in Taiwan to conduct a retrospective cohort study. The inclusion criteria for CHF were patients who were >20 years old and were diagnosed with CHF between January 1, 2005 and December 31, 2012. COPD patients included those who had outpatient visit claims ≥2 times within 365 days or 1 claim for hospitalization with a COPD diagnosis. A time-dependent Cox proportional hazards regression model was applied to evaluate the effectiveness of β-blockers in the study population. Results We identified 1,872 patients with concurrent CHF and COPD. Only high-dose bisoprolol significantly reduced the risk of death and slightly decreased the hospitalization rate due to CHF exacerbation (death: adjusted hazard ratio [aHR] =0.51, 95% confidence interval [CI] =0.29–0.89; hospitalization rate due to CHF exacerbation: aHR =0.48, 95% CI =0.23–1.00). No association was observed between β-blocker use and COPD exacerbation. Conclusion In patients with concurrent CHF and COPD, β-blockers reduced mortality, CHF exacerbation, and the need for hospitalization. Bisoprolol was found to reduce mortality and CHF exacerbation compared to carvedilol and metoprolol. PMID:28894360

Identifying Significant Changes in Cerebrovascular Reactivity to Carbon Dioxide.

PubMed

Sobczyk, O; Crawley, A P; Poublanc, J; Sam, K; Mandell, D M; Mikulis, D J; Duffin, J; Fisher, J A

2016-05-01

Changes in cerebrovascular reactivity can be used to assess disease progression and response to therapy but require discrimination of pathology from normal test-to-test variability. Such variability is due to variations in methodology, technology, and physiology with time. With uniform test conditions, our aim was to determine the test-to-test variability of cerebrovascular reactivity in healthy subjects and in patients with known cerebrovascular disease. Cerebrovascular reactivity was the ratio of the blood oxygen level-dependent MR imaging response divided by the change in carbon dioxide stimulus. Two standardized cerebrovascular reactivity tests were conducted at 3T in 15 healthy men (36.7 ± 16.1 years of age) within a 4-month period and were coregistered into standard space to yield voxelwise mean cerebrovascular reactivity interval difference measures, composing a reference interval difference atlas. Cerebrovascular reactivity interval difference maps were prepared for 11 male patients. For each patient, the test-retest difference of each voxel was scored statistically as z-values of the corresponding voxel mean difference in the reference atlas and then color-coded and superimposed on the anatomic images to create cerebrovascular reactivity interval difference z-maps. There were no significant test-to-test differences in cerebrovascular reactivity in either gray or white matter (mean gray matter, P = .431; mean white matter, P = .857; paired t test) in the healthy cohort. The patient cerebrovascular reactivity interval difference z-maps indicated regions where cerebrovascular reactivity increased or decreased and the probability that the changes were significant. Accounting for normal test-to-test differences in cerebrovascular reactivity enables the assessment of significant changes in disease status (stability, progression, or regression) in patients with time. © 2016 by American Journal of Neuroradiology.

Quantile regression models of animal habitat relationships

USGS Publications Warehouse

Cade, Brian S.

2003-01-01

Typically, all factors that limit an organism are not measured and included in statistical models used to investigate relationships with their environment. If important unmeasured variables interact multiplicatively with the measured variables, the statistical models often will have heterogeneous response distributions with unequal variances. Quantile regression is an approach for estimating the conditional quantiles of a response variable distribution in the linear model, providing a more complete view of possible causal relationships between variables in ecological processes. Chapter 1 introduces quantile regression and discusses the ordering characteristics, interval nature, sampling variation, weighting, and interpretation of estimates for homogeneous and heterogeneous regression models. Chapter 2 evaluates performance of quantile rankscore tests used for hypothesis testing and constructing confidence intervals for linear quantile regression estimates (0 ≤ τ ≤ 1). A permutation F test maintained better Type I errors than the Chi-square T test for models with smaller n, greater number of parameters p, and more extreme quantiles τ. Both versions of the test required weighting to maintain correct Type I errors when there was heterogeneity under the alternative model. An example application related trout densities to stream channel width:depth. Chapter 3 evaluates a drop in dispersion, F-ratio like permutation test for hypothesis testing and constructing confidence intervals for linear quantile regression estimates (0 ≤ τ ≤ 1). Chapter 4 simulates from a large (N = 10,000) finite population representing grid areas on a landscape to demonstrate various forms of hidden bias that might occur when the effect of a measured habitat variable on some animal was confounded with the effect of another unmeasured variable (spatially and not spatially structured). Depending on whether interactions of the measured habitat and unmeasured variable were negative (interference interactions) or positive (facilitation interactions), either upper (τ > 0.5) or lower (τ < 0.5) quantile regression parameters were less biased than mean rate parameters. Sampling (n = 20 - 300) simulations demonstrated that confidence intervals constructed by inverting rankscore tests provided valid coverage of these biased parameters. Quantile regression was used to estimate effects of physical habitat resources on a bivalve mussel (Macomona liliana) in a New Zealand harbor by modeling the spatial trend surface as a cubic polynomial of location coordinates.

Temporal Prediction Errors Affect Short-Term Memory Scanning Response Time.

PubMed

Limongi, Roberto; Silva, Angélica M

2016-11-01

The Sternberg short-term memory scanning task has been used to unveil cognitive operations involved in time perception. Participants produce time intervals during the task, and the researcher explores how task performance affects interval production - where time estimation error is the dependent variable of interest. The perspective of predictive behavior regards time estimation error as a temporal prediction error (PE), an independent variable that controls cognition, behavior, and learning. Based on this perspective, we investigated whether temporal PEs affect short-term memory scanning. Participants performed temporal predictions while they maintained information in memory. Model inference revealed that PEs affected memory scanning response time independently of the memory-set size effect. We discuss the results within the context of formal and mechanistic models of short-term memory scanning and predictive coding, a Bayes-based theory of brain function. We state the hypothesis that our finding could be associated with weak frontostriatal connections and weak striatal activity.

In vivo interaction between ciprofloxacin hydrochloride and the pulp of unripe plantain (Musa paradisiaca).

PubMed

Sv, Nwafor; Co, Esimone; Ca, Amadi; Cs, Nworu

2003-01-01

The absorption of quinolone antibiotics is seriously impaired by polyvalent cations due to the formation of unabsorbable complexes. M. paradisiaca Linn. (Musaceae), an important staple food in most parts of the world, has been demonstrated to contain many polyvalent cations. The aim of the work was to study the influence of concurrent administration of M. paradisiaca and ciprofloxacin HCI on the pharmacokinetic profiles of ciprofloxacin. The study was carried out in two phases in five healthy male rabbits. Phase one involved oral administration of ciprofloxacin (40 mg/kg) to rabbits, withdrawing blood from the marginal ear vein at 1, 2, 4, and 24 h intervals and checking the serum ciprofloxacin concentration. After a one-week drug "wash-out" period, the second phase started with concurrent oral administration of M. paradisiaca (800 mg/kg) and ciprofloxacin (40 mg/kg). Blood was again withdrawn and analyzed for serum ciprofloxacin content. Antimicrobial activity of the serum was also assessed and expressed as reciprocal serum inhibitory titer. Co-administration of both agents resulted in significant (P<0.05) decrease in serum concentration of ciprofloxacin at all the time interval except at the 24th hour. The following pharmacokinetic parameters were also decreased: area under the curve (81.53%), peak serum concentration (94.37%), elimination rate constant (42.35%); while increase in half-life (81.08%) and clearance rate (69.64%) were noted. Antimicrobial study showed that the antimicrobial potency against E. coli was also decreased by such concurrent administration. The pharmacokinetic parameters and antimicrobial activities of ciprofloxacin were significantly decreased when it was given concurrently with pulp of unripe plantain. Complex formation between the drug and the polyvalent cations present in plantain, leading to decrease in absorption and hence bioavailability, may be responsible for the observed antagonistic interactions.

Radical-intent hypofractionated radiotherapy for locally advanced non-small-cell lung cancer: a systematic review of the literature.

PubMed

Kaster, Tyler S; Yaremko, Brian; Palma, David A; Rodrigues, George B

2015-03-01

To identify survival and toxicity characteristics associated with radical-intent hypofractionated radiotherapy for the treatment of stage III non-small-cell lung cancer (NSCLC). Relevant studies were identified from a systematic PubMed search of articles published between January 1990 and January 2014. All studies were peer reviewed and included both retrospective and prospective studies of NSCLC patients being treated with radical hypofractionated radiotherapy. Data on overall survival (OS) and toxicity were extracted from each of the studies where available. Of 685 studies initially identified by the search, a total of 33 studies were found to be relevant and were included in this systematic review. The number of fractions ranged from 15 to 35, the dose per fraction ranged from 2.3 to 3.5 Gy, and the delivered dose ranged from 45.0 to 85.5 Gy. Fifteen of the studies included concurrent chemotherapy, while 18 did not. OS was found to be associated with tumor biological effective dose, with the Pearson correlation coefficient ranging from 0.34 to 0.48. For both concurrent and nonconcurrent chemoradiotherapy acute pulmonary, late esophageal and late pulmonary incidences of toxicity ranged from 1.2% to 12.2%, but had 95% confidence intervals that included zero. The greatest incidence of toxicity was acute esophageal toxicity at 14.9% (95% confidence interval, 0.7%, 29.1%). There is a moderate linear relationship between biological effective dose and OS, and greater acute esophageal toxicity with concurrent chemotherapy. Improving outcomes in stage III NSCLC may involve some form of hypofractionation in the context of systemic concurrent therapy. Copyright © 2015 Elsevier Inc. All rights reserved.

Time, rate, and conditioning.

PubMed

Gallistel, C R; Gibbon, J

2000-04-01

The authors draw together and develop previous timing models for a broad range of conditioning phenomena to reveal their common conceptual foundations: First, conditioning depends on the learning of the temporal intervals between events and the reciprocals of these intervals, the rates of event occurrence. Second, remembered intervals and rates translate into observed behavior through decision processes whose structure is adapted to noise in the decision variables. The noise and the uncertainties consequent on it have both subjective and objective origins. A third feature of these models is their timescale invariance, which the authors argue is a very important property evident in the available experimental data. This conceptual framework is similar to the psychophysical conceptual framework in which contemporary models of sensory processing are rooted. The authors contrast it with the associative conceptual framework.

Variable dual-frequency electrostatic wave launcher for plasma applications.

PubMed

Jorns, Benjamin; Sorenson, Robert; Choueiri, Edgar

2011-12-01

A variable tuning system is presented for launching two electrostatic waves concurrently in a magnetized plasma. The purpose of this system is to satisfy the wave launching requirements for plasma applications where maximal power must be coupled into two carefully tuned electrostatic waves while minimizing erosion to the launching antenna. Two parallel LC traps with fixed inductors and variable capacitors are used to provide an impedance match between a two-wave source and a loop antenna placed outside the plasma. Equivalent circuit analysis is then employed to derive an analytical expression for the normalized, average magnetic flux density produced by the antenna in this system as a function of capacitance and frequency. It is found with this metric that the wave launcher can couple to electrostatic modes at two variable frequencies concurrently while attenuating noise from the source signal at undesired frequencies. An example based on an experiment for plasma heating with two electrostatic waves is used to demonstrate a procedure for tailoring the wave launcher to accommodate the frequency range and flux densities of a specific two-wave application. This example is also used to illustrate a method based on averaging over wave frequencies for evaluating the overall efficacy of the system. The wave launcher is shown to be particularly effective for the illustrative example--generating magnetic flux densities in excess of 50% of the ideal case at two variable frequencies concurrently--with a high adaptability to a number of plasma dynamics and heating applications.

A Mulitivariate Statistical Model Describing the Compound Nature of Soil Moisture Drought

NASA Astrophysics Data System (ADS)

Manning, Colin; Widmann, Martin; Bevacqua, Emanuele; Maraun, Douglas; Van Loon, Anne; Vrac, Mathieu

2017-04-01

Soil moisture in Europe acts to partition incoming energy into sensible and latent heat fluxes, thereby exerting a large influence on temperature variability. Soil moisture is predominantly controlled by precipitation and evapotranspiration. When these meteorological variables are accumulated over different timescales, their joint multivariate distribution and dependence structure can be used to provide information of soil moisture. We therefore consider soil moisture drought as a compound event of meteorological drought (deficits of precipitation) and heat waves, or more specifically, periods of high Potential Evapotraspiration (PET). We present here a statistical model of soil moisture based on Pair Copula Constructions (PCC) that can describe the dependence amongst soil moisture and its contributing meteorological variables. The model is designed in such a way that it can account for concurrences of meteorological drought and heat waves and describe the dependence between these conditions at a local level. The model is composed of four variables; daily soil moisture (h); a short term and a long term accumulated precipitation variable (Y1 and Y_2) that account for the propagation of meteorological drought to soil moisture drought; and accumulated PET (Y_3), calculated using the Penman Monteith equation, which can represent the effect of a heat wave on soil conditions. Copula are multivariate distribution functions that allow one to model the dependence structure of given variables separately from their marginal behaviour. PCCs then allow in theory for the formulation of a multivariate distribution of any dimension where the multivariate distribution is decomposed into a product of marginal probability density functions and two-dimensional copula, of which some are conditional. We apply PCC here in such a way that allows us to provide estimates of h and their uncertainty through conditioning on the Y in the form h=h|y_1,y_2,y_3 (1) Applying the model to various Fluxnet sites across Europe, we find the model has good skill and can particularly capture periods of low soil moisture well. We illustrate the relevance of the dependence structure of these Y variables to soil moisture and show how it may be generalised to offer information of soil moisture on a widespread scale where few observations of soil moisture exist. We then present results from a validation study of a selection of EURO CORDEX climate models where we demonstrate the skill of these models in representing these dependencies and so offer insight into the skill seen in the representation of soil moisture in these models.

American Solar Eclipses 2017 & 2024

NASA Astrophysics Data System (ADS)

DiCanzio, Albert

2016-06-01

This research focuses on harnessing the statistical capacity of many available concurrent observers to advance scientific knowledge. By analogy to some Galilean measurement-experiments in which he used minimal instrumentation, this researcher will address the question: How might an individual observer, with a suitably chosen common metric and with widely available, reasonably affordable equipment, contribute to new knowledge from observing the solar eclipse of 2017? Each observer would report data to an institutional sponsor who would analyze these data statistically toward new knowledge about some question currently unsettled in astronomy or in the target field connected with the question which the chosen metric is targeted to address. A subordinate question will be discussed: As a tradeoff between “best question to answer” and “easiest question for observers’ data to answer”, is there an event property and related target question that, with high potential utility and low cost, would be measurable by an observer positioned in the path of totality with minimal or inexpensive equipment and training? (And that, as a statistical sample point, might contribute to new knowledge?) In dialog with the audience, the presenter will suggest some measurables; e.g., solar flares, ground shadow bands, atmospheric metrics, coronal structure, etc., correlated or not with certain other dependent variables. The independent variable would be time in the intervention interval from eclipse contacts 1 -- 4. By the aforementioned analogy, the presenter will review as examples some measurement-experiments conducted or suggested by Galileo; e.g., pendulum laws, Jovian satellite eclipse times, geokinesis as later seen in Bessel's parallactic measurement, and Michelson's measurement of light speed. Because criteria of metrics-determination would naturally include existence of a data-collection-analysis method, this presentation requires dialogue with a critical mass of audience members who would participate in the consideration of the research objective and of candidate institutional sponsors as a function of candidate target questions.

Hydrological responses of the Chihuahua Desert of Mexico to possible Heinrich Stadials: A study inferred from geochemistry and stable isotopes of lacustrine sediments

NASA Astrophysics Data System (ADS)

Quiroz-Jiménez, J. D.; Roy, P. D.; Lozano-SantaCruz, R.; López Balbiaux, N.; Girón-García, P.

2016-12-01

The Heinrich Stadials (H6-H1) were cooler intervals of different duration characterized by massive discharge of icebergs from the Laurentide Ice Sheet mainly through the Hudson Straight into the Atlantic Ocean. In this paper, we present a proxy record to infer hydrological responses of the Chihuahua Desert of Mexico to all the Heinrich Stadials (HS) from element ratios, CO3 abundance, and oxygen and carbon isotope compositions of lacustrine calcite of the sediments deposited between depths of 560-78 cm ( 66-8 ka) of a new core collected from the Santiaguillo Basin. Sediments deposited during different HS were identified by radiocarbon dating up to 27.3 ka, extrapolation of an average sediment rate and tuning the CO3 abundance record with insolation in rest of the sequence, and oxygen isotope composition of authigenic CO3. Proxies suggest that hydroclimate of the Chihuahua Desert of Mexico responded differently to different HS. The overall runoff and hence precipitation remained below average during H6, H4, H2 and H1. Both of them were above average during H5 and H3. Similarly, runoff during H4 showed the least variability and it was the most variable during H5. Except for H2, negative excursions in δ18O values suggest cooler conditions during all other HS. In general, dissolved HCO3- was mainly sourced from the atmospheric CO2 during arid intervals. Both the lake productivity and atmospheric CO2 influenced the carbon isotope composition of dissolved HCO3- during humid intervals. During the H2, δ13C values indicate dominant influence of lacustrine productivity. Similar to Chihuahua Desert of Mexico, speleothem records from Fort Stanton and Cave of the Bells (Asmerom et al., 2010; Wagner et al., 2010) showed that hydroclimate of southwest USA also experienced millennial-scale variability and some intervals were more homogeneous compared to others. We did not observe concurrency in proxy records of the Chihuahua Desert of Mexico and southwest USA. Instead, we observed a possible hemispheric link between hydroclimate of the Chihuahua Desert of Mexico and the East Asian Monsoon. Characterized by millennial-scale fluctuations, tendencies of runoff into the Santiaguillo Basin and intensity of the East Asian Monsoon inferred from speleothems from the Hulu Cave of China (Wang et al., 2001) across the six HS were similar.

Reliability and Concurrent Validity of Dynamic Rotator Stability Test-A Cross Sectional study.

PubMed

Binoy Mathew, K V; Eapen, Charu; Kumar, P Senthil

2012-01-01

To find intra rater and inter rater reliability of Dynamic Rotator Stability Test (DRST) and to find concurrent validity of Dynamic Rotator Stability Test (DRST) with University of Pennsylvania Shoulder Score (PENN) Scale. 40 subjects of either gender between the age group of 18-70 with painful shoulder conditions of musculoskeletal origin was selected through convenient sampling. Tester 1 and tester 2 administered DRST and PENN scale randomly. In a subgroup of 20 subjects DRST was administered by both the testers to find the inter rater reliability. 180° Standard Universal Goniometer was used to take measurements. For intra-rater reliability, all the test variables were showing highly significant correlation (p=.94 - 1). For inter -rater, with tester 2, test variables like position, ROM, force, direction of abnormal translation, pain during the test, compensatory movement during test were found to be significant (p=.71-1).only some variables of DRST showed significant correlation with PENN scale (P=.320-.450). Dynamic Rotator Stability Test has good intra rater and moderate inter rater reliability. Concurrent validity of Dynamic Rotator Stability Test was found to be poor when compared to PENN Shoulder Score.

A Response Surface Methodology for Bi-Level Integrated System Synthesis (BLISS)

NASA Technical Reports Server (NTRS)

Altus, Troy David; Sobieski, Jaroslaw (Technical Monitor)

2002-01-01

The report describes a new method for optimization of engineering systems such as aerospace vehicles whose design must harmonize a number of subsystems and various physical phenomena, each represented by a separate computer code, e.g., aerodynamics, structures, propulsion, performance, etc. To represent the system internal couplings, the codes receive output from other codes as part of their inputs. The system analysis and optimization task is decomposed into subtasks that can be executed concurrently, each subtask conducted using local state and design variables and holding constant a set of the system-level design variables. The subtasks results are stored in form of the Response Surfaces (RS) fitted in the space of the system-level variables to be used as the subtask surrogates in a system-level optimization whose purpose is to optimize the system objective(s) and to reconcile the system internal couplings. By virtue of decomposition and execution concurrency, the method enables a broad workfront in organization of an engineering project involving a number of specialty groups that might be geographically dispersed, and it exploits the contemporary computing technology of massively concurrent and distributed processing. The report includes a demonstration test case of supersonic business jet design.

Simulation of daily pesticide concentrations from watershed characteristics and monthly climatic data

USGS Publications Warehouse

Vecchia, Aldo V.; Crawford, Charles G.

2006-01-01

A time-series model was developed to simulate daily pesticide concentrations for streams in the coterminous United States. The model was based on readily available information on pesticide use, climatic variability, and watershed charac-teristics and was used to simulate concentrations for four herbicides [atrazine, ethyldipropylthiocarbamate (EPTC), metolachlor, and trifluralin] and three insecticides (carbofuran, ethoprop, and fonofos) that represent a range of physical and chemical properties, application methods, national application amounts, and areas of use in the United States. The time-series model approximates the probability distributions, seasonal variability, and serial correlation characteristics in daily pesticide concentration data from a national network of monitoring stations. The probability distribution of concentrations for a particular pesticide and station was estimated using the Watershed Regressions for Pesticides (WARP) model. The WARP model, which was developed in previous studies to estimate the probability distribution, was based on selected nationally available watershed-characteristics data, such as pesticide use and soil characteristics. Normality transformations were used to ensure that the annual percentiles for the simulated concentrations agree closely with the percentiles estimated from the WARP model. Seasonal variability in the transformed concentrations was maintained by relating the transformed concentration to precipitation and temperature data from the United States Historical Climatology Network. The monthly precipitation and temperature values were estimated for the centroids of each watershed. Highly significant relations existed between the transformed concentrations, concurrent monthly precipitation, and concurrent and lagged monthly temperature. The relations were consistent among the different pesticides and indicated the transformed concentrations generally increased as precipitation increased but the rate of increase depended on a temperature-dependent growing-season effect. Residual variability of the transformed concentrations, after removal of the effects of precipitation and temperature, was partitioned into a signal (systematic variability that is related from one day to the next) and noise (random variability that is not related from one day to the next). Variograms were used to evaluate measurement error, seasonal variability, and serial correlation of the historical data. The variogram analysis indicated substantial noise resulted, at least in part, from measurement errors (the differences between the actual concen-trations and the laboratory concentrations). The variogram analysis also indicated the presence of a strongly correlated signal, with an exponentially decaying serial correlation function and a correlation time scale (the time required for the correlation to decay to e-1 equals 0.37) that ranged from about 18 to 66 days, depending on the pesticide type. Simulated daily pesticide concentrations from the time-series model indicated the simulated concentrations for the stations located in the northeastern quadrant of the United States where most of the monitoring stations are located generally were in good agreement with the data. The model neither consistently overestimated or underestimated concentrations for streams that are located in this quadrant and the magnitude and timing of high or low concentrations generally coincided reasonably well with the data. However, further data collection and model development may be necessary to determine whether the model should be used for areas for which few historical data are available.

The Interaction of Sexual Validation, Criminal Justice Involvement, and Sexually Transmitted Infection Risk Among Adolescent and Young Adult Males.

PubMed

Matson, Pamela A; Towe, Vivian; Ellen, Jonathan M; Chung, Shang-En; Sherman, Susan G

2018-03-01

Young men who have been involved with the criminal justice system are more likely to have concurrent sexual partners, a key driver of sexually transmitted infections. The value men place on having sexual relationships to validate themselves may play an important role in understanding this association. Data were from a household survey. Young men (N = 132), aged 16 to 24 years, self-reported whether they ever spent time in jail or juvenile detention and if they had sexual partnerships that overlapped in time. A novel scale, "Validation through Sex and Sexual Relationships" (VTSSR) assessed the importance young men place on sex and sexual relationships (α = 0.91). Weighted logistic regression accounted for the sampling design. The mean (SD) VTSSR score was 23.7 (8.8) with no differences by race. Both criminal justice involvement (CJI) (odds ratio [OR], 3.69; 95% confidence interval [CI], 1.12-12.1) and sexual validation (OR, 1.10; 95% CI, 1.04-1.16) were associated with an increased odds of concurrency; however, CJI did not remain associated with concurrency in the fully adjusted model. There was effect modification, CJI was associated with concurrency among those who scored high on sexual validation (OR, 9.18; 95% CI, 1.73-48.6]; however, there was no association among those who scored low on sexual validation. Racial differences were observed between CJI and concurrency, but not between sexual validation and concurrency. Sexual validation may be an important driver of concurrency for men who have been involved with the criminal justice system. Study findings have important implications on how sexual validation may explain racial differences in rates of concurrency.

DETERMINANTS OF TEMPORAL VARIABILITY IN NHEXAS-MARYLAND ENVIRONMENTAL CONCENTRATIONS, EXPOSURES, AND BIOMARKERS

EPA Science Inventory

The longitudinal NHEXAS-Maryland study measured metals, PAHs, and pesticides in several media to capture temporal variability. Questionnaires were concurrently administered to identify factors that influenced changes in contaminant levels over time. We constructed mixed-effects...

Shoulder pain and time dependent structure in wheelchair propulsion variability.

PubMed

Jayaraman, Chandrasekaran; Moon, Yaejin; Sosnoff, Jacob J

2016-07-01

Manual wheelchair propulsion places considerable repetitive mechanical strain on the upper limbs leading to shoulder injury and pain. While recent research indicates that the amount of variability in wheelchair propulsion and shoulder pain may be related. There has been minimal inquiry into the fluctuation over time (i.e. time-dependent structure) in wheelchair propulsion variability. Consequently the purpose of this investigation was to examine if the time-dependent structure in the wheelchair propulsion parameters are related to shoulder pain. 27 experienced wheelchair users manually propelled their own wheelchair fitted with a SMARTWheel on a roller at 1.1m/s for 3min. Time-dependent structure of cycle-to-cycle fluctuations in contact angle and inter push time interval was quantified using sample entropy (SampEn) and compared between the groups with/without shoulder pain using non-parametric statistics. Overall findings were, (1) variability observed in contact angle fluctuations during manual wheelchair propulsion is structured (Z=3.15;p<0.05), (2) individuals with shoulder pain exhibited higher SampEn magnitude for contact angle during wheelchair propulsion than those without pain (χ(2)(1)=6.12;p<0.05); and (3) SampEn of contact angle correlated significantly with self-reported shoulder pain (rs (WUSPI) =0.41;rs (VAS)=0.56;p<0.05). It was concluded that the time-dependent structure in wheelchair propulsion may provide novel information for tracking and monitoring shoulder pain. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

Modelling long-term impacts of mountain pine beetle outbreaks on merchantable biomass, ecosystem carbon, albedo, and radiative forcing

NASA Astrophysics Data System (ADS)

Landry, Jean-Sébastien; Parrott, Lael; Price, David T.; Ramankutty, Navin; Damon Matthews, H.

2016-09-01

The ongoing major outbreak of mountain pine beetle (MPB) in forests of western North America has led to considerable research efforts. However, many questions remain unaddressed regarding its long-term impacts, especially when accounting for the range of possible responses from the non-target vegetation (i.e., deciduous trees and lower-canopy shrubs and grasses). We used the Integrated BIosphere Simulator (IBIS) process-based ecosystem model along with the recently incorporated Marauding Insect Module (MIM) to quantify, over 240 years, the impacts of various MPB outbreak regimes on lodgepole pine merchantable biomass, ecosystem carbon, surface albedo, and the net radiative forcing on global climate caused by the changes in ecosystem carbon and albedo. We performed simulations for three locations in British Columbia, Canada, with different climatic conditions, and four scenarios of various coexisting vegetation types with variable growth release responses. The impacts of MPB outbreaks on merchantable biomass (decrease) and surface albedo (increase) were similar across the 12 combinations of locations and vegetation coexistence scenarios. The impacts on ecosystem carbon and radiative forcing, however, varied substantially in magnitude and sign, depending upon the presence and response of the non-target vegetation, particularly for the two locations not subjected to growing-season soil moisture stress; this variability represents the main finding from our study. Despite major uncertainty in the value of the resulting radiative forcing, a simple analysis also suggested that the MPB outbreak in British Columbia will have a smaller impact on global temperature over the coming decades and centuries than a single month of global anthropogenic CO2 emissions from fossil fuel combustion and cement production. Moreover, we found that (1) outbreak severity (i.e., per-event mortality) had a stronger effect than outbreak return interval on the variables studied, (2) MPB-induced changes in carbon dynamics had a stronger effect than concurrent changes in albedo on net radiative forcing, and (3) the physical presence of MPB-killed dead standing trees was potentially beneficial to tree regrowth. Given that the variability of pre-outbreak vegetation characteristics can lead to very different regeneration pathways, the four vegetation coexistence scenarios we simulated probably only sampled the range of possible responses.

Using a Programmable Calculator to Teach Teophylline Pharmacokinetics.

ERIC Educational Resources Information Center

Closson, Richard Grant

1981-01-01

A calculator program for a Texas Instruments Model 59 to predict serum theophylline concentrations is described. The program accommodates the input of multiple dose times at irregular intervals, clearance changes due to concurrent patient diseases and age less than 17 years. The calculations for five hypothetical patients are given. (Author/MLW)

Cross-cultural adaptation and psychometric evaluation of oral health impact profile among school teacher community

PubMed Central

Vyas, Shaleen; Nagarajappa, Sandesh; Dasar, Pralhad L.; Mishra, Prashant

2018-01-01

AIM: To translate OHIP-14 into Hindi and test its psychometric properties among school teacher community. METHODS: The OHIP-14 was translated to OHIP-14-H using WHO recommended translation protocol. During pre-testing, an expert panel assessed content validity of the questionnaire. Face validity was assessed on a sample of 10 individuals. The OHIP-14-H was administered on a random sample of 170 primary school teachers. Internal consistency and test-retest reliability were assessed using Cronbach's alpha and Intra-class correlation coefficient (ICC) respectively, with 2 weeks interval. Predictive validity was tested by comparing OHIP-14-H scores with clinical parameters. The concurrent validity was assessed using self-reported oral health and discriminant validity was ascertained through negative association with sociodemographic variables. RESULTS: The mean OHIP-14-H score was 9.57 (S.D = 4.58). ICC and Cronbach's alpha for OHIP-14-H was 0.96 and 0.92 respectively. Concurrent validity using binomial regression model indicated that good (OR = 0.56, 95% CI = 0.55 – 4.47) and moderate (OR = 0.25, 95% CI = 0.17 – 1.87) OHIP-14-H scores were negative but significant risk indicators of poor self reported oral health (P < 0.009). Significant predictive validity was observed between OHIP-14-H scores and clinical parameters (P < 0.000). CONCLUSION: Translated and culturally adapted OHIP-14-H indicates good reliability and validity among primary school teachers. PMID:29417064

CSM solutions of rotating blade dynamics using integrating matrices

NASA Technical Reports Server (NTRS)

Lakin, William D.

1992-01-01

The dynamic behavior of flexible rotating beams continues to receive considerable research attention as it constitutes a fundamental problem in applied mechanics. Further, beams comprise parts of many rotating structures of engineering significance. A topic of particular interest at the present time involves the development of techniques for obtaining the behavior in both space and time of a rotor acted upon by a simple airload loading. Most current work on problems of this type use solution techniques based on normal modes. It is certainly true that normal modes cannot be disregarded, as knowledge of natural blade frequencies is always important. However, the present work has considered a computational structural mechanics (CSM) approach to rotor blade dynamics problems in which the physical properties of the rotor blade provide input for a direct numerical solution of the relevant boundary-and-initial-value problem. Analysis of the dynamics of a given rotor system may require solution of the governing equations over a long time interval corresponding to many revolutions of the loaded flexible blade. For this reason, most of the common techniques in computational mechanics, which treat the space-time behavior concurrently, cannot be applied to the rotor dynamics problem without a large expenditure of computational resources. By contrast, the integrating matrix technique of computational mechanics has the ability to consistently incorporate boundary conditions and 'remove' dependence on a space variable. For problems involving both space and time, this feature of the integrating matrix approach thus can generate a 'splitting' which forms the basis of an efficient CSM method for numerical solution of rotor dynamics problems.

Lasting depression in corticomotor excitability associated with local scalp cooling.

PubMed

Tremblay, François; Remaud, Anthony; Mekonnen, Abeye; Gholami-Boroujeny, Shiva; Racine, Karl-Édouard; Bolic, Miodrag

2015-07-23

In this study, we investigated the effect of local scalp cooling on corticomotor excitability with transcranial magnetic simulation (TMS). Participants (healthy male adults, n=12) were first assessed with TMS to derive baseline measure of excitability from motor evoked potentials (MEPs) using the right first dorsal interosseous as the target muscle. Then, local cooling was induced on the right hemi-scalp (upper frontal region ∼ 15 cm(2)) by means of a cold wrap. The cooling was maintained for 10-15 min to get a decrease of at least 10°C from baseline temperature. In the post-cooling period, both scalp temperature and MEPs were reassessed at specific time intervals (i.e., T0, T10, T20 and T30 min). Scalp surface temperatures dropped on average by 12.5°C from baseline at T0 (p<0.001) with partial recovery at T10 (p<0.05) and full recovery at T20. Parallel analysis of post-cooling variations in MEP amplitude revealed significant reductions relative to baseline at T0, T10 and T20. No concurrent change in MEP latency was observed. A secondary control experiment was performed in a subset of participants (n=5) to account for the mild discomfort associated with the wrapping procedure without the cooling agent. Results showed no effect on any of the dependent variables (temperature, MEP amplitude and latency). To our knowledge, this report provides the first neurophysiological evidence linking changes in scalp temperature with lasting changes in corticomotor excitability. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Generating variable and random schedules of reinforcement using Microsoft Excel macros.

PubMed

Bancroft, Stacie L; Bourret, Jason C

2008-01-01

Variable reinforcement schedules are used to arrange the availability of reinforcement following varying response ratios or intervals of time. Random reinforcement schedules are subtypes of variable reinforcement schedules that can be used to arrange the availability of reinforcement at a constant probability across number of responses or time. Generating schedule values for variable and random reinforcement schedules can be difficult. The present article describes the steps necessary to write macros in Microsoft Excel that will generate variable-ratio, variable-interval, variable-time, random-ratio, random-interval, and random-time reinforcement schedule values.

Air Pollution and Autonomic and Vascular Dysfunction in Patients With Cardiovascular Disease: Interactions of Systemic Inflammation, Overweight, and Gender

PubMed Central

Huang, Wei; Zhu, Tong; Pan, Xiaochuan; Hu, Min; Lu, Shou-En; Lin, Yong; Wang, Tong; Zhang, Yuanhang; Tang, Xiaoyan

2012-01-01

The authors conducted a 2-year follow-up of 40 cardiovascular disease patients (mean age = 65.6 years (standard deviation, 5.8)) who underwent repeated measurements of cardiovascular response before and during the 2008 Beijing Olympics (Beijing, China), when air pollution was strictly controlled. Ambient levels of particulate matter with an aerodynamic diameter less than 2.5 µm (PM2.5), black carbon, nitrogen dioxide, sulfur dioxide, ozone, and carbon monoxide were measured continuously, with validation of concurrent real-time measurements of personal exposure to PM2.5 and carbon monoxide. Linear mixed-effects models were used with adjustment for individual risk factors, time-varying factors, and meteorologic effects. Significant heart rate variability reduction and blood pressure elevation were observed in association with exposure to air pollution. Specifically, interquartile-range increases of 51.8 µg/m3, 2.02 µg/m3, and 13.7 ppb in prior 4-hour exposure to PM2.5, black carbon, and nitrogen dioxide were associated with significant reductions in the standard deviation of the normal-to-normal intervals of 4.2% (95% confidence interval (CI): 1.9, 6.4), 4.2% (95% CI: 1.8, 6.6), and 3.9% (95% CI: 2.2, 5.7), respectively. Greater heart rate variability declines were observed among subjects with C-reactive protein values above the 90th percentile, subjects with a body mass index greater than 25, and females. The authors conclude that autonomic and vascular dysfunction may be one of the mechanisms through which air pollution exposure can increase cardiovascular disease risk, especially among persons with systemic inflammation and overweight. PMID:22763390

Punishment in human choice: direct or competitive suppression?

PubMed Central

Critchfield, Thomas S; Paletz, Elliott M; MacAleese, Kenneth R; Newland, M Christopher

2003-01-01

This investigation compared the predictions of two models describing the integration of reinforcement and punishment effects in operant choice. Deluty's (1976) competitive-suppression model (conceptually related to two-factor punishment theories) and de Villiers' (1980) direct-suppression model (conceptually related to one-factor punishment theories) have been tested previously in nonhumans but not at the individual level in humans. Mouse clicking by college students was maintained in a two-alternative concurrent schedule of variable-interval money reinforcement. Punishment consisted of variable-interval money losses. Experiment 1 verified that money loss was an effective punisher in this context. Experiment 2 consisted of qualitative model comparisons similar to those used in previous studies involving nonhumans. Following a no-punishment baseline, punishment was superimposed upon both response alternatives. Under schedule values for which the direct-suppression model, but not the competitive-suppression model, predicted distinct shifts from baseline performance, or vice versa, 12 of 14 individual-subject functions, generated by 7 subjects, supported the direct-suppression model. When the punishment models were converted to the form of the generalized matching law, least-squares linear regression fits for a direct-suppression model were superior to those of a competitive-suppression model for 6 of 7 subjects. In Experiment 3, a more thorough quantitative test of the modified models, fits for a direct-suppression model were superior in 11 of 13 cases. These results correspond well to those of investigations conducted with nonhumans and provide the first individual-subject evidence that a direct-suppression model, evaluated both qualitatively and quantitatively, describes human punishment better than a competitive-suppression model. We discuss implications for developing better punishment models and future investigations of punishment in human choice. PMID:13677606

Influence of velocity on variability in gait kinematics: implications for recognition in forensic science.

PubMed

Yang, Sylvia X M; Larsen, Peter K; Alkjaer, Tine; Lynnerup, Niels; Simonsen, Erik B

2014-09-01

Closed circuit television (CCTV) footage is often available from crime scenes and may be used to compare perpetrators with suspects. Usually, the footage comprises incomplete gait cycles at different velocities, making gait pattern identification from crimes difficult. This study investigated the concurrence of joint angles throughout a gait cycle at three different velocities (3.0, 4.5, 6.0 km/h). Six datasets at each velocity were collected from 16 men. A variability range VR throughout the gait cycle at each velocity for each joint angle for each person was calculated. The joint angles at each velocity were compared pairwise, and whenever this showed values within the VR of this velocity, the case was positive. By adding the positives throughout the gait cycle, phases with high and low concurrences were located; peak concurrence was observed at mid-stance phase. Striving for the same velocity for the suspect and perpetrator is recommended. © 2014 American Academy of Forensic Sciences.

Evidence for increased behavioral control by punishment in children with attention-deficit hyperactivity disorder.

PubMed

Furukawa, Emi; Alsop, Brent; Sowerby, Paula; Jensen, Stephanie; Tripp, Gail

2017-03-01

The behavioral sensitivity of children with ADHD to punishment has received limited theoretical and experimental attention. This study evaluated the effects of punishment on the response allocation of children with ADHD and typically developing children. Two hundred and ten children, 145 diagnosed with ADHD, completed an operant task in which they chose between playing two simultaneously available games. Reward was arranged symmetrically across the games under concurrent variable interval schedules. Asymmetric punishment schedules were superimposed; responses on one game were punished four times as often as responses on the other. Both groups allocated more of their responses to the less frequently punished alternative. Response bias increased significantly in the ADHD group during later trials, resulting in missed reward trials and reduced earnings. Punishment exerted greater control over the response allocation of children with ADHD with increased time on task. Children with ADHD appear more sensitive to the cumulative effects of punishment than typically developing children. © 2016 Association for Child and Adolescent Mental Health.

Correlating regional natural hazards for global reinsurance risk assessment

NASA Astrophysics Data System (ADS)

Steptoe, Hamish; Maynard, Trevor; Economou, Theo; Fox, Helen; Wallace, Emily; Maisey, Paul

2016-04-01

Concurrent natural hazards represent an uncertainty in assessing exposure for the insurance industry. The recently implemented Solvency II Directive requires EU insurance companies to fully understand and justify their capital reserving and portfolio decisions. Lloyd's, the London insurance and reinsurance market, commissioned the Met Office to investigate the dependencies between different global extreme weather events (known to the industry as perils), and the mechanisms for these dependencies, with the aim of helping them assess their compound risk to the exposure of multiple simultaneous hazards. In this work, we base the analysis of hazard-to-hazard dependency on the interaction of different modes of global and regional climate variability. Lloyd's defined 16 key hazard regions, including Australian wildfires, flooding in China and EU windstorms, and we investigate the impact of 10 key climate modes on these areas. We develop a statistical model that facilitates rapid risk assessment whilst allowing for both temporal auto-correlation and, crucially, interdependencies between drivers. The simulator itself is built conditionally using autoregressive regression models for each driver conditional on the others. Whilst the baseline assumption within the (re)insurance industry is that different natural hazards are independent of each other, the assumption of independence of meteorological risks requires greater justification. Although our results suggest that most of the 120 hazard-hazard connections considered are likely to be independent of each other, 13 have significant dependence arising from one or more global modes of climate variability. This allows us to create a matrix of linkages describing the hazard dependency structure that Lloyd's can use to inform their understanding of risk.

Cigarette smoking and associated health risks among students at five universities.

PubMed

Halperin, Abigail C; Smith, Stevens S; Heiligenstein, Eric; Brown, David; Fleming, Michael F

2010-02-01

While most college students and other young adults who smoke fall into the light and intermittent smoking (LITS) category, they remain at risk for tobacco dependence and other adverse health effects from their smoking. This study examines smoking patterns, tobacco dependence, and other health variables among students at five universities to better understand how to identify and address tobacco use and related risks in a college health clinic setting. A health screening survey was completed by 2,091 college and graduate student volunteers seeking routine care at their university health centers or participating in a health class. Independent health variables were analyzed descriptively and in regression analyses with three levels of smoking (none, non-daily, and daily) and tobacco dependence to determine predictors and associated risks. Nearly a quarter of students reported any current smoking, 41% of whom reported smoking less than 1 cigarette/day (cpd). Of the daily smokers, 80% smoked less than 10 cpd but 45% met criteria for tobacco dependence. Any smoking was associated with high-risk alcohol use, risky driving, relational abuse, depression, less exercise, and utilization of emergency and mental health services. In regression analyses, students who experienced depression had more than double the odds of being dependent smokers (odds ratio [OR] = 2.32), as did those who reported abuse (OR = 2.07) or sought mental health counseling (OR = 2.09). Student health providers should be alerted to the multiple risks and comorbidities that occur among all smokers, including LITS, and intervene concurrently to help prevent or mitigate adverse outcomes that result from these conditions and behaviors.

Cigarette smoking and associated health risks among students at five universities

PubMed Central

Smith, Stevens S.; Heiligenstein, Eric; Brown, David; Fleming, Michael F.

2010-01-01

Introduction: While most college students and other young adults who smoke fall into the light and intermittent smoking (LITS) category, they remain at risk for tobacco dependence and other adverse health effects from their smoking. This study examines smoking patterns, tobacco dependence, and other health variables among students at five universities to better understand how to identify and address tobacco use and related risks in a college health clinic setting. Methods: A health screening survey was completed by 2,091 college and graduate student volunteers seeking routine care at their university health centers or participating in a health class. Independent health variables were analyzed descriptively and in regression analyses with three levels of smoking (none, non-daily, and daily) and tobacco dependence to determine predictors and associated risks. Results: Nearly a quarter of students reported any current smoking, 41% of whom reported smoking less than 1 cigarette/day (cpd). Of the daily smokers, 80% smoked less than 10 cpd but 45% met criteria for tobacco dependence. Any smoking was associated with high-risk alcohol use, risky driving, relational abuse, depression, less exercise, and utilization of emergency and mental health services. In regression analyses, students who experienced depression had more than double the odds of being dependent smokers (odds ratio [OR] = 2.32), as did those who reported abuse (OR = 2.07) or sought mental health counseling (OR = 2.09). Discussion: Student health providers should be alerted to the multiple risks and comorbidities that occur among all smokers, including LITS, and intervene concurrently to help prevent or mitigate adverse outcomes that result from these conditions and behaviors. PMID:20018947

A single-loop optimization method for reliability analysis with second order uncertainty

NASA Astrophysics Data System (ADS)

Xie, Shaojun; Pan, Baisong; Du, Xiaoping

2015-08-01

Reliability analysis may involve random variables and interval variables. In addition, some of the random variables may have interval distribution parameters owing to limited information. This kind of uncertainty is called second order uncertainty. This article develops an efficient reliability method for problems involving the three aforementioned types of uncertain input variables. The analysis produces the maximum and minimum reliability and is computationally demanding because two loops are needed: a reliability analysis loop with respect to random variables and an interval analysis loop for extreme responses with respect to interval variables. The first order reliability method and nonlinear optimization are used for the two loops, respectively. For computational efficiency, the two loops are combined into a single loop by treating the Karush-Kuhn-Tucker (KKT) optimal conditions of the interval analysis as constraints. Three examples are presented to demonstrate the proposed method.

Concurrent relations among cigarette smoking status, resting heart rate variability, and erectile response.

PubMed

Harte, Christopher B

2014-05-01

Heart rate variability (HRV) is a marker of sympathovagal balance; it has been implicated in erectile function and is also altered by tobacco use. Furthermore, smoking and erectile health are strongly related, given that smokers are at increased risk for erectile dysfunction. Few studies have explored the interrelationships between smoking, HRV, and erectile function concurrently. The aim of this study was to examine potential mechanisms underlying tobacco's effects on penile hemodynamics by exploring the mediating role of HRV. The sample comprised 119 men (smokers = 64; nonsmokers = 55) (mean age 28.90 years; standard deviation (SD) 11.68; range 18-58) selected from the control conditions of three previously published experiments. Participants were free from a history of cardiovascular disease, myocardial infarct, and/or cardiac/cardiovascular medication use. During a laboratory visit, self-report, anthropometric, cardiovascular, and electrocardiographic data were assessed, as well as sexual arousal responses elicited from viewing an erotic film. Objective sexual arousal indices (circumferential change via penile plethysmography), self-reported erectile function (per the erectile function domain score of the International Index of Erectile Function [IIEF-EF]), and time- (SD of beat-to-beat intervals) and frequency-domain parameters of HRV (ratio of low-frequency [LF] power to high-frequency [HF] power [LF/HF ratio]) were assessed. Being a current long-term cigarette smoker was associated with dysregulated sympathovagal balance (higher LF/HF ratios, indicative of sympathetic nervous system dominance), which in turn showed inverse relations with magnitude of erectile tumescence. HRV did not mediate relations between tobacco use and either IIEF-EF scores or resting penile circumference. Findings suggest that dysfunctional cardiac autonomic tone may be an underlying mechanism by which tobacco exerts its deleterious effects on erectile health. Further research is necessary to determine whether this relationship is mechanistic in nature, or whether it is better explained by other health factors. © 2014 International Society for Sexual Medicine.

Sex ratio, poverty, and concurrent partnerships among men and women in the United States: a multilevel analysis.

PubMed

Adimora, Adaora A; Schoenbach, Victor J; Taylor, Eboni M; Khan, Maria R; Schwartz, Robert J; Miller, William C

2013-11-01

Social and economic contextual factors may promote concurrent sexual partnerships, which can accelerate population HIV transmission and are more common among African Americans than U.S. Whites. We investigated the relationship between contextual factors and concurrency. We analyzed past 12-month concurrency prevalence in the 2002 National Survey of Family Growth and its contextual database in relation to county sex ratio (among respondent's racial and ethnic group), percentage in poverty (among respondent's racial and ethnic group), and violent crime rate. Analyses examined counties with balanced (0.95-1.05 males/female) or low (<0.9) sex ratios. Concurrency prevalence was greater (odds ratio [OR]; 95% confidence interval [CI]) in counties with low sex ratios (OR, 1.67; 95% CI, 1.17-2.39), more poverty (OR, 1.18; 95% CI, 0.98-1.42 per 10 percentage-point increase), and higher crime rates (OR, 1.04; 95% CI, 1.00-1.09 per 1000 population/year). Notably, 99.5% of Whites and 93.7% of Hispanics, but only 7.85% of Blacks, lived in balanced sex ratio counties; about 5% of Whites, half of Hispanics, and three-fourths of Blacks resided in counties with >20% same-race poverty. The dramatic Black-White differences in contextual factors in the United States and their association with sexual concurrency could contribute to the nation's profound racial disparities in HIV infection. Copyright © 2013 Elsevier Inc. All rights reserved.

The prevalence of stroke and depression and factors associated with depression in elderly people with and without stroke.

PubMed

Hörnsten, Carl; Lövheim, Hugo; Nordström, Peter; Gustafson, Yngve

2016-10-07

Few studies have investigated factors associated with depression among elderly people with and without stroke concurrently, using identical settings, procedures and study variables. The aim was to investigate the prevalence of stroke and depression and to compare the factors associated with depression in people with and without stroke. A postal mail survey was sent to 65-, 70-, 75- and 80-year-olds in northern Sweden and Finland in 2010 (n = 6098). Stroke was defined as answering "yes" to the question "Have you had a stroke?" Depression was defined as answering "yes" to the question "Are you depressed?" or having a Geriatric Depression Scale-4 score ≥2. Dependence in personal activities of daily living was defined as not showering without human assistance. Associations were tested with log-binomial regression. The overall stroke prevalence was 7.0 ± 0.3 % and increased from 4.7 ± 0.4 % among 65-year-olds to 11.6 ± 1.0 % among 80-year-olds (p < 0.001). The overall depression prevalence was 12.8 ± 0.4 % and increased from 11.0 ± 0.6 % among 65-year-olds to 18.1 ± 1.2 % among 80-year-olds (p < 0.001). Depression was more common among people with stroke (Prevalence Ratio 1.77, 95 % Confidence Interval 1.48-2.12). In the non-stroke group, depression was independently associated with diabetes, dependence in instrumental activities of daily living, living alone, not having someone to talk to, poor finances, pain problems and having a life crisis in the preceding year. In the group with stroke, depression was independently associated with dependence in personal activities of daily living and having a life crisis the preceding year. Depression in people without stroke appeared to be independently associated with a broader range of external factors than depression in people with stroke.

Scheme for generating distillation-favorable continuous-variable entanglement via three concurrent parametric down-conversions in a single χ⁽²⁾ nonlinear photonic crystal.

PubMed

Gong, Yan-Xiao; Zhang, ShengLi; Xu, P; Zhu, S N

2016-03-21

We propose to generate a single-mode-squeezing two-mode squeezed vacuum state via a single χ⁽²⁾ nonlinear photonic crystal. The state is favorable for existing Gaussian entanglement distillation schemes, since local squeezing operations can enhance the final entanglement and the success probability. The crystal is designed for enabling three concurrent quasi-phase-matching parametric-down conversions, and hence relieves the auxiliary on-line bi-side local squeezing operations. The compact source opens up a way for continuous-variable quantum technologies and could find more potential applications in future large-scale quantum networks.

Response Variability across Diverse Rice Accessions under Rising Temperature and Increasing Atmospheric Carbon Dioxide

USDA-ARS?s Scientific Manuscript database

Evaluating variability of rice response to concurrent increases in CO2 and temperature forecasted for future climates is a prerequisite step towards characterizing the genetic architecture underlying this response. Expanding on previous single cultivar studies, we evaluated eleven biogeographically ...

Generating Variable and Random Schedules of Reinforcement Using Microsoft Excel Macros

PubMed Central

Bancroft, Stacie L; Bourret, Jason C

2008-01-01

Variable reinforcement schedules are used to arrange the availability of reinforcement following varying response ratios or intervals of time. Random reinforcement schedules are subtypes of variable reinforcement schedules that can be used to arrange the availability of reinforcement at a constant probability across number of responses or time. Generating schedule values for variable and random reinforcement schedules can be difficult. The present article describes the steps necessary to write macros in Microsoft Excel that will generate variable-ratio, variable-interval, variable-time, random-ratio, random-interval, and random-time reinforcement schedule values. PMID:18595286

Effect of concurrent training on risk factors and hepatic steatosis in obese adolescents

PubMed Central

Antunes, Barbara de Moura M.; Monteiro, Paula Alves; Silveira, Loreana Sanches; Cayres, Suziane Ungari; da Silva, Camila Buonani; F., Ismael Forte

2013-01-01

OBJECTIVE To analyze the effects of a 20-week concurrent training on the variables of body composition, lipid profile, and fatty liver diagnosis in obese adolescents. METHODS An open clinical trial was carried out with 34 obese adolescents aged between 12 and 15 years. Total body fat, trunk fat mass, total cholesterol and its fractions (HDL, LDL and VLDL), and triglycerides were analyzed; an upper abdominal ultrasound was performed in order to diagnose fatty liver. The participants underwent concurrent training (association of weight training with aerobic training) three times per week, lasting one hour for 20 weeks. Statistical analysis included paired Studentâ€(tm)s t-test and frequency analysis in order to verify the relative and absolute reductions of fatty liver diagnosis, being significant p<0.05. RESULTS The studied adolescents showed statistically significant improvement in body composition, with a decrease of total body fat percentage, total fat mass, trunk fat, and an a increase in the lean body mass. They also presented reduced size of liver lobes, decrease in total cholesterol and in LDL-cholesterol, with a lower prevalence of fatty liver. CONCLUSIONS The concurrent training was effective for promoting significant improvements in body fat composition and lipid profile variables, besides reducing fatty liver prevalence rate. PMID:24142321

Comparison of dehydroepiandrosterone (DHEA) and pregnanolone with existing pharmacotherapies for alcohol abuse on ethanol- and food-maintained responding in male rats

PubMed Central

Hulin, Mary W.; Lawrence, Michelle N.; Amato, Russell J.; Weed, Peter F.; Winsauer, Peter J.

2015-01-01

The present study compared two putative pharmacotherapies for alcohol abuse and dependence, dehydroepiandrosterone (DHEA) and pregnanolone, with two Food and Drug Administration (FDA)-approved pharmacotherapies, naltrexone and acamprosate. Experiment 1 assessed the effects of different doses of DHEA, pregnanolone, naltrexone, and acamprosate on both ethanol- and food-maintained responding under a multiple fixed-ratio (FR)-10 FR-20 schedule, respectively. Experiment 2 assessed the effects of different mean intervals of food presentation on responding for ethanol under an FR-10 variable-interval (VI) schedule, whereas Experiment 3 assessed the effects of a single dose of each drug under a FR-10 VI-80 schedule. In Experiment 1, all four drugs dose-dependently decreased response rate for both food and ethanol, although differences in the rate-decreasing effects were apparent among the drugs. DHEA and pregnanolone decreased ethanol-maintained responding more potently than food-maintained responding, whereas the reverse was true for naltrexone. Acamprosate decreased responding for both reinforcers with equal potency. In Experiment 2, different mean intervals of food presentation significantly affected the number of food reinforcers obtained per session; however, changes in the number of food reinforcements did not significantly affect responding for ethanol. Under the FR-10 VI-80 schedule in Experiment 3, only naltrexone significantly decreased both the dose of alcohol presented and blood ethanol concentration (BEC). Acamprosate and pregnanolone had no significant effects on any of the dependent measures, whereas DHEA significantly decreased BEC, but did not significantly decrease response rate or the dose presented. In summary, DHEA and pregnanolone decreased ethanol-maintained responding more potently than food-maintained responding under a multiple FR-10 FR-20 schedule, and were more selective for decreasing ethanol self-administration than either naltrexone or acamprosate under that schedule. Experiment 2 showed that ethanol intake was relatively independent of the density of reinforcement in the food-maintained component, and Experiment 3 showed that naltrexone was the most effective drug at the doses tested when the density for food reinforcement was low and maintained under a variable-interval schedule. PMID:25620274

How do Rumination and Social Problem Solving Intensify Depression? A Longitudinal Study.

PubMed

Hasegawa, Akira; Kunisato, Yoshihiko; Morimoto, Hiroshi; Nishimura, Haruki; Matsuda, Yuko

2018-01-01

In order to examine how rumination and social problem solving intensify depression, the present study investigated longitudinal associations among each dimension of rumination and social problem solving and evaluated aspects of these constructs that predicted subsequent depression. A three-wave longitudinal study, with an interval of 4 weeks between waves, was conducted. Japanese university students completed the Beck Depression Inventory-Second Edition, Ruminative Responses Scale, Social Problem-Solving Inventory-Revised Short Version, and Interpersonal Stress Event Scale on three occasions 4 weeks apart ( n  = 284 at Time 1, 198 at Time 2, 165 at Time 3). Linear mixed models were analyzed to test whether each variable predicted subsequent depression, rumination, and each dimension of social problem solving. Rumination and negative problem orientation demonstrated a mutually enhancing relationship. Because these two variables were not associated with interpersonal conflict during the subsequent 4 weeks, rumination and negative problem orientation appear to strengthen each other without environmental change. Rumination and impulsivity/carelessness style were associated with subsequent depressive symptoms, after controlling for the effect of initial depression. Because rumination and impulsivity/carelessness style were not concurrently and longitudinally associated with each other, rumination and impulsive/careless problem solving style appear to be independent processes that serve to intensify depression.

HIV-1 subtype A gag variability and epitope evolution.

PubMed

Abidi, Syed Hani; Kalish, Marcia L; Abbas, Farhat; Rowland-Jones, Sarah; Ali, Syed

2014-01-01

The aim of this study was to examine the course of time-dependent evolution of HIV-1 subtype A on a global level, especially with respect to the dynamics of immunogenic HIV gag epitopes. We used a total of 1,893 HIV-1 subtype A gag sequences representing a timeline from 1985 through 2010, and 19 different countries in Africa, Europe and Asia. The phylogenetic relationship of subtype A gag and its epidemic dynamics was analysed through a Maximum Likelihood tree and Bayesian Skyline plot, genomic variability was measured in terms of G → A substitutions and Shannon entropy, and the time-dependent evolution of HIV subtype A gag epitopes was examined. Finally, to confirm observations on globally reported HIV subtype A sequences, we analysed the gag epitope data from our Kenyan, Pakistani, and Afghan cohorts, where both cohort-specific gene epitope variability and HLA restriction profiles of gag epitopes were examined. The most recent common ancestor of the HIV subtype A epidemic was estimated to be 1956 ± 1. A period of exponential growth began about 1980 and lasted for approximately 7 years, stabilized for 15 years, declined for 2-3 years, then stabilized again from about 2004. During the course of evolution, a gradual increase in genomic variability was observed that peaked in 2005-2010. We observed that the number of point mutations and novel epitopes in gag also peaked concurrently during 2005-2010. It appears that as the HIV subtype A epidemic spread globally, changing population immunogenetic pressures may have played a role in steering immune-evolution of this subtype in new directions. This trend is apparent in the genomic variability and epitope diversity of HIV-1 subtype A gag sequences.

Phonation interval modification and speech performance quality during fluency-inducing conditions by adults who stutter

PubMed Central

Ingham, Roger J.; Bothe, Anne K.; Wang, Yuedong; Purkhiser, Krystal; New, Anneliese

2012-01-01

Purpose To relate changes in four variables previously defined as characteristic of normally fluent speech to changes in phonatory behavior during oral reading by persons who stutter (PWS) and normally fluent controls under multiple fluency-inducing (FI) conditions. Method Twelve PWS and 12 controls each completed 4 ABA experiments. During A phases, participants read normally. B phases were 4 different FI conditions: auditory masking, chorus reading, whispering, and rhythmic stimulation. Dependent variables were the durations of accelerometer-recorded phonated intervals; self-judged speech effort; and observer-judged stuttering frequency, speech rate, and speech naturalness. The method enabled a systematic replication of Ingham et al. (2009). Results All FI conditions resulted in decreased stuttering and decreases in the number of short phonated intervals, as compared with baseline conditions, but the only FI condition that satisfied all four characteristics of normally fluent speech was chorus reading. Increases in longer phonated intervals were associated with decreased stuttering but also with poorer naturalness and/or increased speech effort. Previous findings concerning the effects of FI conditions on speech naturalness and effort were replicated. Conclusions Measuring all relevant characteristics of normally fluent speech, in the context of treatments that aim to reduce the occurrence of short-duration PIs, may aid the search for an explanation of the nature of stuttering and may also maximize treatment outcomes for adults who stutter. PMID:22365886

Dyadic Perfectionism as a Predictor of Relationship Continuity and Distress among College Students

ERIC Educational Resources Information Center

Lopez, Frederick G.; Fons-Scheyd, Alia; Morua, Wendy; Chaliman, Rebecca

2006-01-01

This study examined the nature and impact of dyadic perfectionism over a 3-month interval within a sample of 116 college students who were currently involved in an intimate heterosexual relationship. Dyadic perfectionism scores were stable and correlated as expected with scores on concurrent measures of adult attachment orientations and…

Psychological Distance to Reward: Effects of S+ Duration and the Delay Reduction It Signals

ERIC Educational Resources Information Center

Alessandri, Jerome; Stolarz-Fantino, Stephanie; Fantino, Edmund

2011-01-01

A concurrent-chains procedure was used to examine choice between segmented (two-component chained schedules) and unsegmented schedules (simple schedules) in terminal links with equal inter-reinforcement intervals. Previous studies using this kind of experimental procedure showed preference for unsegmented schedules for both pigeons and humans. In…

Effect of Light/Dark Cycle on Wheel Running and Responding Reinforced by the Opportunity to Run Depends on Postsession Feeding Time

ERIC Educational Resources Information Center

Belke, T. W.; Mondona, A. R.; Conrad, K. M.; Poirier, K. F.; Pickering, K. L.

2008-01-01

Do rats run and respond at a higher rate to run during the dark phase when they are typically more active? To answer this question, Long Evans rats were exposed to a response-initiated variable interval 30-s schedule of wheel-running reinforcement during light and dark cycles. Wheel-running and local lever-pressing rates increased modestly during…

Integrated Resistance and Aerobic Training Maintains Cardiovascular and Skeletal Muscle Fitness During 14 Days of Bed Rest

NASA Technical Reports Server (NTRS)

Ploutz-Snyder, Lori; Goetchius, Elizabeth; Crowell, Brent; Hackney, Kyle; Wickwire, Jason; Ploutz-Snyder, Robert; Snyder, Scott

2012-01-01

Background: Known incompatibilities exist between resistance and aerobic training. Of particular importance are findings that concurrent resistance and aerobic training reduces the effectiveness of the resistance training and limits skeletal muscle adaptations (example: Dudley & Djamil, 1985). Numerous unloading studies have documented the effectiveness of resistance training alone for the maintenance of skeletal muscle size and strength. However the practical applications of those studies are limited because long ]duration crew members perform both aerobic and resistance exercise throughout missions/spaceflight. To date, such integrated training on the International Space Station (ISS) has not been fully effective in the maintenance of skeletal muscle function. Purpose: The purpose of this study was to evaluate the efficacy of high intensity concurrent resistance and aerobic training for the maintenance of cardiovascular fitness and skeletal muscle strength, power and endurance over 14 days of strict bed rest. Methods: 9 subjects (8 male and 1 female; 34.5 +/- 8.2 years) underwent 14 days of bed rest with concurrent training. Resistance and aerobic training were integrated as shown in table 1. Days that included 2 exercise sessions had a 4-8 hour rest between exercise bouts. The resistance training consisted of 3 sets of 12 repetitions of squat, heel raise, leg press and hamstring curl exercise. Aerobic exercise consisted of periodized interval training that included 30 sec, 2 min and 4 min intervals alternating by day with continuous aerobic exercise.

The effects of cognitive loading on balance control in patients with multiple sclerosis.

PubMed

Negahban, Hossein; Mofateh, Razieh; Arastoo, Ali Asghar; Mazaheri, Masood; Yazdi, Mohammad Jafar Shaterzadeh; Salavati, Mahyar; Majdinasab, Nastaran

2011-10-01

The aim of this study was to compare the effects of concurrent cognitive task (silent backward counting) on balance performance between two groups of multiple sclerosis (MS) (n=23) and healthy (n=23) participates. Three levels of postural difficulty were studied on a force platform, i.e. rigid surface with eyes open, rigid surface with eyes closed, and foam surface with eyes closed. A mixed model analysis of variance showed that under difficult sensory condition of foam surface with eyes closed, execution of concurrent cognitive task caused a significant decrement in variability of sway velocity in anteroposterior direction for the patient group (P<0.01) while this was not the case for healthy participants (P=0.22). Also, the variability of sway velocity in mediolateral direction was significantly decreased during concurrent execution of cognitive task in patient group (P<0.01) and not in healthy participants (P=0.39). Furthermore, in contrast to single tasking, dual tasking had the ability to discriminate between the 2 groups in all conditions of postural difficulty. In conclusion, findings of variability in sway velocity seem to confirm the different response to cognitive loading between two groups of MS and healthy participants. Copyright © 2011 Elsevier B.V. All rights reserved.

Feasibility of Ecological Momentary Assessment Using Cellular Telephones in Methamphetamine Dependent Subjects

PubMed Central

Galloway, Gantt P; Didier, Ryne; Garrison, Kathleen; Mendelson, John

2008-01-01

Background Predictors of relapse to methamphetamine use are poorly understood. State variables may play an important role in relapse, but they have been difficult to measure at frequent intervals in outpatients. Methods We conducted a feasibility study of the use of cellular telephones to collect state variable data from outpatients. Six subjects in treatment for methamphetamine dependence were called three times per weekday for approximately seven weeks. Seven questionnaires were administered that assessed craving, stress, affect and current type of location and social environment. Results 395/606 (65%) of calls attempted were completed. The mean time to complete each call was 4.9 (s.d. 1.8) minutes and the mean time to complete each item was 8.4 (s.d. 4.8) seconds. Subjects rated the acceptability of the procedures as good. All six cellular phones and battery chargers were returned undamaged. Conclusion Cellular telephones are a feasible method for collecting state data from methamphetamine dependent outpatients. PMID:19997532

Thermally stratified flow of second grade fluid with non-Fourier heat flux and temperature dependent thermal conductivity

NASA Astrophysics Data System (ADS)

Khan, M. Ijaz; Zia, Q. M. Zaigham; Alsaedi, A.; Hayat, T.

2018-03-01

This attempt explores stagnation point flow of second grade material towards an impermeable stretched cylinder. Non-Fourier heat flux and thermal stratification are considered. Thermal conductivity dependents upon temperature. Governing non-linear differential system is solved using homotopic procedure. Interval of convergence for the obtained series solutions is explicitly determined. Physical quantities of interest have been examined for the influential variables entering into the problems. It is examined that curvature parameter leads to an enhancement in velocity and temperature. Further temperature for non-Fourier heat flux model is less than Fourier's heat conduction law.

Polynomial chaos expansion with random and fuzzy variables

NASA Astrophysics Data System (ADS)

Jacquelin, E.; Friswell, M. I.; Adhikari, S.; Dessombz, O.; Sinou, J.-J.

2016-06-01

A dynamical uncertain system is studied in this paper. Two kinds of uncertainties are addressed, where the uncertain parameters are described through random variables and/or fuzzy variables. A general framework is proposed to deal with both kinds of uncertainty using a polynomial chaos expansion (PCE). It is shown that fuzzy variables may be expanded in terms of polynomial chaos when Legendre polynomials are used. The components of the PCE are a solution of an equation that does not depend on the nature of uncertainty. Once this equation is solved, the post-processing of the data gives the moments of the random response when the uncertainties are random or gives the response interval when the variables are fuzzy. With the PCE approach, it is also possible to deal with mixed uncertainty, when some parameters are random and others are fuzzy. The results provide a fuzzy description of the response statistical moments.

The distribution of middle tropospheric carbon monoxide during early October 1984

NASA Technical Reports Server (NTRS)

Reichle, Henry G., Jr.; Connors, Vickie S.; Wallio, H. Andrew; Holland, J. Alvin; Sherrill, Robert T.; Casas, Joseph C.; Gormsen, Barbara B.

1989-01-01

The distribution of middle tropospheric carbon monoxide measure by the Measurement of Air Pollution from Satellites (MAPS) instrument carried aboard the space shuttle is reported. The data represent average mixing ratios in the middle troposphere and are presented in the form of maps that show the carbon monoxide mixing ratios averaged for 6 days of the mission. Comparisons with concurrent, direct measurements taken aboard aircraft show that the inferred concentrations are systematically low by from 20 to 40 percent depending upon which direct measurement calibration standard is used. The data show that there are very large CO sources resulting from biomass burning over South America and southern Africa. Measured mixing ratios were high over northeast Asia and were highly variable over Europe.

Signaled and Unsignaled Terminal Links in Concurrent Chains I: Effects of Reinforcer Probability and Immediacy

ERIC Educational Resources Information Center

Mattson, Karla M.; Hucks, Andrew; Grace, Randolph C.; McLean, Anthony P.

2010-01-01

Eight pigeons responded in a three-component concurrent-chains procedure, with either independent or dependent initial links. Relative probability and immediacy of reinforcement in the terminal links were both varied, and outcomes on individual trials (reinforcement or nonreinforcement) were either signaled or unsignaled. Terminal-link fixed-time…

Effects of stimulus characteristics and task demands on pilots' perception of dichotic messages

NASA Technical Reports Server (NTRS)

Wenzel, Elizabeth M.

1986-01-01

The experiment is an initial investigation of pilot performance when auditory advisory messages are presented dichotically, either with or without a concurrent pursuit task requiring visual/motor dexterity. The dependent measures were percent correct and correct reaction times for manual responses to the auditory messages. Two stimulus variables which show facilitory effects in traditional dichotic-listening paradigms, differences in pitch and semantic content of the messages, were examined to determine their effectiveness during the functional simulation of helicopter pursuit. In an effort to accumulate points for the advisory messages for accuracy alone or for both accuracy and reaction times which were faster than their opponent's. In general, the combined effects of the stimulus and task variables are additive. When interactions do occur they suggest that an increase in task demands can sometimes mitigate, but usually does not remove, any processing advantages accrued from stimulus characteristics. The implications of these results for cockpit displays are discussed.

Comparative metabolism of tramadol and tapentadol: a toxicological perspective.

PubMed

Barbosa, Joana; Faria, Juliana; Queirós, Odília; Moreira, Roxana; Carvalho, Félix; Dinis-Oliveira, Ricardo Jorge

2016-11-01

Tramadol and tapentadol are centrally acting, synthetic opioid analgesics used in the treatment of moderate to severe pain. Main metabolic patterns for these drugs in humans are well characterized. Tramadol is mainly metabolized by cytochrome P450 CYP2D6 to O-desmethyltramadol (M1), its main active metabolite. M1 and tapentadol undergo mainly glucuronidation reactions. On the other hand, the pharmacokinetics of tramadol and tapentadol are dependent on multiple factors, such as the route of administration, genetic variability in pharmacokinetic components and concurrent consumption of other drugs. This review aims to comparatively discuss the metabolomics of tramadol and tapentadol, namely by presenting all their known metabolites. An exhaustive literature search was performed using textual and structural queries for tramadol and tapentadol, and associated known metabolizing enzymes and metabolites. A thorough knowledge about tramadol and tapentadol metabolomics is expected to provide additional insights to better understand the interindividual variability in their pharmacokinetics and dose-responsiveness, and contribute to the establishment of personalized therapeutic approaches, minimizing side effects and optimizing analgesic efficacy.

Perception of visual apparent motion is modulated by a gap within concurrent auditory glides, even when it is illusory

PubMed Central

Wang, Qingcui; Guo, Lu; Bao, Ming; Chen, Lihan

2015-01-01

Auditory and visual events often happen concurrently, and how they group together can have a strong effect on what is perceived. We investigated whether/how intra- or cross-modal temporal grouping influenced the perceptual decision of otherwise ambiguous visual apparent motion. To achieve this, we juxtaposed auditory gap transfer illusion with visual Ternus display. The Ternus display involves a multi-element stimulus that can induce either of two different percepts of apparent motion: ‘element motion’ (EM) or ‘group motion’ (GM). In “EM,” the endmost disk is seen as moving back and forth while the middle disk at the central position remains stationary; while in “GM,” both disks appear to move laterally as a whole. The gap transfer illusion refers to the illusory subjective transfer of a short gap (around 100 ms) from the long glide to the short continuous glide when the two glides intercede at the temporal middle point. In our experiments, observers were required to make a perceptual discrimination of Ternus motion in the presence of concurrent auditory glides (with or without a gap inside). Results showed that a gap within a short glide imposed a remarkable effect on separating visual events, and led to a dominant perception of GM as well. The auditory configuration with gap transfer illusion triggered the same auditory capture effect. Further investigations showed that visual interval which coincided with the gap interval (50–230 ms) in the long glide was perceived to be shorter than that within both the short glide and the ‘gap-transfer’ auditory configurations in the same physical intervals (gaps). The results indicated that auditory temporal perceptual grouping takes priority over the cross-modal interaction in determining the final readout of the visual perception, and the mechanism of selective attention on auditory events also plays a role. PMID:26042055

Perception of visual apparent motion is modulated by a gap within concurrent auditory glides, even when it is illusory.

PubMed

Wang, Qingcui; Guo, Lu; Bao, Ming; Chen, Lihan

2015-01-01

Auditory and visual events often happen concurrently, and how they group together can have a strong effect on what is perceived. We investigated whether/how intra- or cross-modal temporal grouping influenced the perceptual decision of otherwise ambiguous visual apparent motion. To achieve this, we juxtaposed auditory gap transfer illusion with visual Ternus display. The Ternus display involves a multi-element stimulus that can induce either of two different percepts of apparent motion: 'element motion' (EM) or 'group motion' (GM). In "EM," the endmost disk is seen as moving back and forth while the middle disk at the central position remains stationary; while in "GM," both disks appear to move laterally as a whole. The gap transfer illusion refers to the illusory subjective transfer of a short gap (around 100 ms) from the long glide to the short continuous glide when the two glides intercede at the temporal middle point. In our experiments, observers were required to make a perceptual discrimination of Ternus motion in the presence of concurrent auditory glides (with or without a gap inside). Results showed that a gap within a short glide imposed a remarkable effect on separating visual events, and led to a dominant perception of GM as well. The auditory configuration with gap transfer illusion triggered the same auditory capture effect. Further investigations showed that visual interval which coincided with the gap interval (50-230 ms) in the long glide was perceived to be shorter than that within both the short glide and the 'gap-transfer' auditory configurations in the same physical intervals (gaps). The results indicated that auditory temporal perceptual grouping takes priority over the cross-modal interaction in determining the final readout of the visual perception, and the mechanism of selective attention on auditory events also plays a role.

Aging Effects on Cardiac and Respiratory Dynamics in Healthy Subjects across Sleep Stages

PubMed Central

Schumann, Aicko Y.; Bartsch, Ronny P.; Penzel, Thomas; Ivanov, Plamen Ch.; Kantelhardt, Jan W.

2010-01-01

Study Objectives: Respiratory and heart rate variability exhibit fractal scaling behavior on certain time scales. We studied the short-term and long-term correlation properties of heartbeat and breathing-interval data from disease-free subjects focusing on the age-dependent fractal organization. We also studied differences across sleep stages and night-time wake and investigated quasi-periodic variations associated with cardiac risk. Design: Full-night polysomnograms were recorded during 2 nights, including electrocardiogram and oronasal airflow. Setting: Data were collected in 7 laboratories in 5 European countries. Participants: 180 subjects without health complaints (85 males, 95 females) aged from 20 to 89 years. Interventions: None. Measurements and Results: Short-term correlations in heartbeat intervals measured by the detrended fluctuation analysis (DFA) exponent α1 show characteristic age dependence with a maximum around 50–60 years disregarding the dependence on sleep and wake states. Long-term correlations measured by α2 differ in NREM sleep when compared with REM sleep and wake, besides weak age dependence. Results for respiratory intervals are similar to those for α2 of heartbeat intervals. Deceleration capacity (DC) decreases with age; it is lower during REM and deep sleep (compared with light sleep and wake). Conclusion: The age dependence of α1 should be considered when using this value for diagnostic purposes in post-infarction patients. Pronounced long-term correlations (larger α2) for heartbeat and respiration during REM sleep and wake indicate an enhanced control of higher brain regions, which is absent during NREM sleep. Reduced DC possibly indicates an increased cardiovascular risk with aging and during REM and deep sleep. Citation: Schumann AY; Bartsch RP; Penzel T; Ivanov PC; Kantelhardt JW. Aging effects on cardiac and respiratory dynamics in healthy subjects across sleep stages. SLEEP 2010;33(7):943-955. PMID:20614854

Willingness to pay for adverse drug event regulatory actions.

PubMed

Bouvy, Jacoline; Weemers, Just; Schellekens, Huub; Koopmanschap, Marc

2011-11-01

Regulatory requirements for the pharmaceutical industry have become increasingly demanding with respect to the safety and effectiveness of drugs. The objective of this study was to determine the willingness to pay (WTP), of both the Dutch general public and dialysis patients, for regulatory requirements related to reducing the risk of pure red cell aplasia (PRCA) associated with epoetin alpha use. A survey was carried out in April 2009. The Dutch general public (n = 422) was approached through a survey sampling agency. Patients (n = 112) were included through several Dutch dialysis clinics because they are often treated with epoetin alpha and therefore were expected to have a higher WTP than the general public. The survey aimed to determine the WTP for reducing the risk of PRCA in epoetin alpha users from 4.5 to 0 per 10 000 patients per year, based on regulatory actions that have been taken by the European Medicines Agency (EMA). WTP was determined via a payment scale and an open-ended follow-up question. Patients were asked how much extra per year they would be willing to pay for their basic healthcare insurance. We used two censored regression models to test the association between WTP and a set of independent variables: a Tobit model with the stated WTP as the dependent variable and an interval regression model with the interval between the lower and upper bounds of the payment scale as the dependent variable. The patients' mean WTP was significantly higher (€46.52) than that of the general public (€24.40). The Tobit model showed significant associations (α = 0.05) with WTP for dialysis patients, risk perception and respondents' opinions on costs of healthcare. The interval regression model showed significant associations with WTP for the same variables as the Tobit model and for one additional variable (risk aversion). Income did not significantly affect WTP. A scenario with a 10-fold larger risk reduction did not increase WTP significantly. This study is, as far as we know, one of the first attempts to analyse the WTP for drug regulation and should in future be used in studies of the societal costs of drug regulation for epoetin alpha use. Our results indicate that the Dutch general public, especially Dutch dialysis patients, are willing to pay limited amounts to reduce the risk of serious adverse events associated with drug use.

Assessing Mediational Models: Testing and Interval Estimation for Indirect Effects.

PubMed

Biesanz, Jeremy C; Falk, Carl F; Savalei, Victoria

2010-08-06

Theoretical models specifying indirect or mediated effects are common in the social sciences. An indirect effect exists when an independent variable's influence on the dependent variable is mediated through an intervening variable. Classic approaches to assessing such mediational hypotheses ( Baron & Kenny, 1986 ; Sobel, 1982 ) have in recent years been supplemented by computationally intensive methods such as bootstrapping, the distribution of the product methods, and hierarchical Bayesian Markov chain Monte Carlo (MCMC) methods. These different approaches for assessing mediation are illustrated using data from Dunn, Biesanz, Human, and Finn (2007). However, little is known about how these methods perform relative to each other, particularly in more challenging situations, such as with data that are incomplete and/or nonnormal. This article presents an extensive Monte Carlo simulation evaluating a host of approaches for assessing mediation. We examine Type I error rates, power, and coverage. We study normal and nonnormal data as well as complete and incomplete data. In addition, we adapt a method, recently proposed in statistical literature, that does not rely on confidence intervals (CIs) to test the null hypothesis of no indirect effect. The results suggest that the new inferential method-the partial posterior p value-slightly outperforms existing ones in terms of maintaining Type I error rates while maximizing power, especially with incomplete data. Among confidence interval approaches, the bias-corrected accelerated (BC a ) bootstrapping approach often has inflated Type I error rates and inconsistent coverage and is not recommended; In contrast, the bootstrapped percentile confidence interval and the hierarchical Bayesian MCMC method perform best overall, maintaining Type I error rates, exhibiting reasonable power, and producing stable and accurate coverage rates.

Radiation dose to patients and image quality evaluation from coronary 256-slice computed tomographic angiography

NASA Astrophysics Data System (ADS)

Chen, Liang-Kuang; Wu, Tung-Hsin; Yang, Ching-Ching; Tsai, Chia-Jung; Lee, Jason J. S.

2010-07-01

The aim of this study is to assess radiation dose and the corresponding image quality from suggested CT protocols which depends on different mean heart rate and high heart rate variability by using 256-slice CT. Fifty consecutive patients referred for a cardiac CT examination were included in this study. All coronary computed tomographic angiography (CCTA) examinations were performed on a 256-slice CT scanner with one of five different protocols: retrospective ECG-gating (RGH) with full dose exposure in all R-R intervals (protocol A), RGH of 30-80% pulsing window with tube current modulation (B), RGH of 78±5% pulsing window with tube current modulation (C), prospective ECG-triggering (PGT) of 78% R-R interval with 5% padding window (D) and PGT of 78% R-R interval without padding window (E). Radiation dose parameters and image quality scoring were determined and compared. In this study, no significant differences were found in comparison on image quality of the five different protocols. Protocol A obtained the highest radiation dose comparing with those of protocols B, C, D and E by a factor of 1.6, 2.4, 2.5 and 4.3, respectively ( p<0.001), which were ranged between 2.7 and 11.8 mSv. The PGT could significantly reduce radiation dose delivered to patients, as compared to the RGH. However, the use of PGT has limitations and is only good in assessing cases with lower mean heart rate and stable heart rate variability. With higher mean heart rate and high heart rate variability circumstances, the RGH within 30-80% of R-R interval pulsing window is suggested as a feasible technique for assessing diagnostic performance.

Constraint-based Attribute and Interval Planning

NASA Technical Reports Server (NTRS)

Jonsson, Ari; Frank, Jeremy

2013-01-01

In this paper we describe Constraint-based Attribute and Interval Planning (CAIP), a paradigm for representing and reasoning about plans. The paradigm enables the description of planning domains with time, resources, concurrent activities, mutual exclusions among sets of activities, disjunctive preconditions and conditional effects. We provide a theoretical foundation for the paradigm, based on temporal intervals and attributes. We then show how the plans are naturally expressed by networks of constraints, and show that the process of planning maps directly to dynamic constraint reasoning. In addition, we de ne compatibilities, a compact mechanism for describing planning domains. We describe how this framework can incorporate the use of constraint reasoning technology to improve planning. Finally, we describe EUROPA, an implementation of the CAIP framework.

Concurrent Disorders and Health Care Utilization Among Homeless and Vulnerably Housed Persons in Canada.

PubMed

Zhang, Linda; Norena, Monica; Gadermann, Anne; Hubley, Anita; Russell, Lara; Aubry, Tim; To, Matthew J; Farrell, Susan; Hwang, Stephen; Palepu, Anita

2018-01-01

Individuals who are homeless or vulnerably housed have a higher prevalence of concurrent disorders, defined as having a mental health diagnosis and problematic substance use, compared to the general housed population. The study objective was to investigate the effect of having concurrent disorders on health care utilization among homeless or vulnerably housed individuals, using longitudinal data from the Health and Housing in Transition Study. In 2009, 1190 homeless or vulnerably housed adults were recruited in Ottawa, Toronto, and Vancouver, Canada. Participants completed baseline interviews and four annual follow-up interviews, providing data on sociodemographics, housing history, mental health diagnoses, problematic drug use with the Drug Abuse Screening Test (DAST-10), problematic alcohol use with the Alcohol Use Disorders Identification Test (AUDIT), chronic health conditions, and utilization of the following health care services: emergency department (ED), hospitalization, and primary care. Concurrent disorders were defined as the participant having ever received a mental health diagnosis at baseline and having problematic substance use (i.e., DAST-10 ≥ 6 and/or AUDIT ≥ 20) at any time during the study period. Three generalized mixed effects logistic regression models were used to examine the independent association of having concurrent disorders and reporting ED use, hospitalization, or primary care visits in the past 12 months. Among our sample of adults who were homeless or vulnerably housed, 22.6% (n = 261) reported having concurrent disorders at baseline. Individuals with concurrent disorders had significantly higher odds of ED use (adjusted odds ratio [AOR] = 1.71; 95% confidence interval [CI], 1.4-2.11), hospitalization (AOR = 1.45; 95% CI, 1.16-1.81), and primary care visits (AOR = 1.34; 95% CI, 1.05-1.71) in the past 12 months over the four-year follow-up period, after adjusting for potential confounders. Concurrent disorders were associated with higher rates of health care utilization when compared to those without concurrent disorders among homeless and vulnerably housed individuals. Comprehensive programs that integrate mental health and addiction services with primary care as well as community-based outreach may better address the unmet health care needs of individuals living with concurrent disorders who are vulnerable to poor health outcomes.

Interactions between sleeping position and feeding on cardiorespiratory activity in preterm infants.

PubMed

Fifer, William P; Myers, Michael M; Sahni, Rakesh; Ohira-Kist, Kiyoko; Kashyap, Sudha; Stark, Raymond I; Schulze, Karl F

2005-11-01

Infants sleeping in the prone position are at greater risk for sudden infant death syndrome (SIDS). Sleep position-dependent changes in cardiorespiratory activity may contribute to this increased risk. Cardiorespiratory activity is also affected by feeding. Twenty prematurely-born infants were studied at 31-36 weeks postconceptional age while sleeping in the prone and supine positions. Heart rate, respiratory rate, and patterns of variability were recorded during interfeed intervals, and effects of position and time after feeding were analyzed by repeated measures analyses of variance. There were significant effects of both sleeping position and time after feeding. Heart rate is higher and heart period variability is lower in the prone position, and the effects of sleeping position on cardiac functioning are more pronounced during the middle of the intrafeed interval. In preterm infants, autonomic responses to nutrient processing modulate the cardiorespiratory effects of sleeping position. Prone sleeping risk may vary with time after feeding. Copyright 2005 Wiley Periodicals, Inc.

Assessment of cardiac autonomic regulation and ventricular repolarization after off-pump coronary artery bypass grafting.

PubMed

Kalisnik, Jurij M; Avbelj, Viktor; Trobec, Roman; Ivaskovic, Daroslav; Vidmar, Gaj; Troise, Giovanni; Gersak, Borut

2006-01-01

Altered autonomic regulation precipitates cardiac arrhythmias and increases the risk of sudden cardiac death. This risk is further increased by changes in ventricular repolarization. Autonomic regulation is deranged in patients after myocardial on-pump revascularization. We aimed to clarify how off-pump coronary artery bypass grafting (CABG) affects postoperative cardiac autonomic regulation and ventricular repolarization within 4 weeks after CABG. Forty-two patients (mean age, 61.9 +/- 9.3 years; mean EURO score 2.6 +/- 1.9) were electively admitted for off-pump CABG. The electrocardiographic and respiratory waveform recordings were performed in the afternoon in the supine position for 10 minutes. Autonomic modulation was assessed using heart rate variability analysis. Power spectra were computed from 5-minute stable RR intervals using Fourier Transform analysis. Total power of spectra was defined in the range of 0.01 to 0.40 Hz, high-frequency power within 0.15 to 0.40 Hz, and low-frequency power within 0.04 to 0.15 Hz. Normalized power was defined as a ratio of power in each band/total power. The high- and low-frequency power as well as their normalized values indicated cardiac vagal and sympathetic modulation, respectively. Ventricular repolarization was assessed using QT interval, QT interval variability, and QT-RR interdependence analysis. QT intervals were determined from the beginning of the 5-minute segments. QT interval variability was evaluated by a T-wave template-matching algorithm. Pearson correlation between length of RR and QT interval was applied to study QT-RR characteristics. The results were tested for significance using the Fisher exact test, nonpaired t test, and analysis of variance; a P <.05 was considered significant. The frequency of arrhythmic events and heart rate increased from the fourth to the seventh postoperative day and returned to preoperative levels 4 weeks after CABG. Heart rate variability measures indicating autonomic modulation remained depressed even 4 weeks after the procedure. QT variability index increased from -1.2 +/- 0.5 to -0.8 +/- 0.4 on the fourth day after the operation (P <.05) and returned to -1.0 +/- 0.5 4 weeks after CABG (P = not significant). QT-RR correlation decreased from 0.41 to 0.23 (P <.05) and remained significantly impaired as long as 4 weeks after CABG. Observed faster heart rates until 1 week after off-pump CABG imply excessive adrenergic activation, which is comparable to on-pump CABG procedure rates. The results indicate profound autonomic derangement and loss of rate-dependent regulation after off-pump CABG even 4 weeks after operation. Restituted repolarization as assessed by QT variability index 4 weeks postoperatively corresponded with decreased frequency of rhythm disturbances 4 weeks after CABG. The loss of coupling between QT and RR intervals shows increased electrical instability postoperatively, which may serve as an additional promoter for postoperative arrhythmias, especially at higher heart rates.

38 CFR 3.702 - Dependency and indemnity compensation.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 38 Pensions, Bonuses, and Veterans' Relief 1 2013-07-01 2013-07-01 false Dependency and indemnity... ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation Concurrent Benefits and Elections § 3.702 Dependency and indemnity compensation. (a) Right to elect. A person who is eligible for death...

38 CFR 3.702 - Dependency and indemnity compensation.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 38 Pensions, Bonuses, and Veterans' Relief 1 2014-07-01 2014-07-01 false Dependency and indemnity... ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation Concurrent Benefits and Elections § 3.702 Dependency and indemnity compensation. (a) Right to elect. A person who is eligible for death...

38 CFR 3.702 - Dependency and indemnity compensation.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 38 Pensions, Bonuses, and Veterans' Relief 1 2011-07-01 2011-07-01 false Dependency and indemnity... ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation Concurrent Benefits and Elections § 3.702 Dependency and indemnity compensation. (a) Right to elect. A person who is eligible for death...

38 CFR 3.702 - Dependency and indemnity compensation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Dependency and indemnity... ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation Concurrent Benefits and Elections § 3.702 Dependency and indemnity compensation. (a) Right to elect. A person who is eligible for death...

38 CFR 3.702 - Dependency and indemnity compensation.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 38 Pensions, Bonuses, and Veterans' Relief 1 2012-07-01 2012-07-01 false Dependency and indemnity... ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation Concurrent Benefits and Elections § 3.702 Dependency and indemnity compensation. (a) Right to elect. A person who is eligible for death...

Risk of upper gastrointestinal bleeding with selective serotonin reuptake inhibitors with or without concurrent nonsteroidal anti-inflammatory use: a systematic review and meta-analysis.

PubMed

Anglin, Rebecca; Yuan, Yuhong; Moayyedi, Paul; Tse, Frances; Armstrong, David; Leontiadis, Grigorios I

2014-06-01

There is emerging concern that selective serotonin reuptake inhibitors (SSRIs) may be associated with an increased risk of upper gastrointestinal (GI) bleeding, and that this risk may be further increased by concurrent use of nonsteroidal anti-inflammatory (NSAID) medications. Previous reviews of a relatively small number of studies have reported a substantial risk of upper GI bleeding with SSRIs; however, more recent studies have produced variable results. The objective of this study was to obtain a more precise estimate of the risk of upper GI bleeding with SSRIs, with or without concurrent NSAID use. MEDLINE, EMBASE, PsycINFO, the Cochrane central register of controlled trials (through April 2013), and US and European conference proceedings were searched. Controlled trials, cohort, case-control, and cross-sectional studies that reported the incidence of upper GI bleeding in adults on SSRIs with or without concurrent NSAID use, compared with placebo or no treatment were included. Data were extracted independently by two authors. Dichotomous data were pooled to obtain odds ratio (OR) of the risk of upper GI bleeding with SSRIs +/- NSAID, with a 95% confidence interval (CI). The main outcome and measure of the study was the risk of upper GI bleeding with SSRIs compared with placebo or no treatment. Fifteen case-control studies (including 393,268 participants) and four cohort studies were included in the analysis. There was an increased risk of upper GI bleeding with SSRI medications in the case-control studies (OR=1.66, 95% CI=1.44,1.92) and cohort studies (OR=1.68, 95% CI=1.13,2.50). The number needed to harm for upper GI bleeding with SSRI treatment in a low-risk population was 3,177, and in a high-risk population it was 881. The risk of upper GI bleeding was further increased with the use of both SSRI and NSAID medications (OR=4.25, 95% CI=2.82,6.42). SSRI medications are associated with a modest increase in the risk of upper GI bleeding, which is lower than has previously been estimated. This risk is significantly elevated when SSRI medications are used in combination with NSAIDs, and physicians prescribing these medications together should exercise caution and discuss this risk with patients.

The distribution of the intervals between neural impulses in the maintained discharges of retinal ganglion cells.

PubMed

Levine, M W

1991-01-01

Simulated neural impulse trains were generated by a digital realization of the integrate-and-fire model. The variability in these impulse trains had as its origin a random noise of specified distribution. Three different distributions were used: the normal (Gaussian) distribution (no skew, normokurtic), a first-order gamma distribution (positive skew, leptokurtic), and a uniform distribution (no skew, platykurtic). Despite these differences in the distribution of the variability, the distributions of the intervals between impulses were nearly indistinguishable. These inter-impulse distributions were better fit with a hyperbolic gamma distribution than a hyperbolic normal distribution, although one might expect a better approximation for normally distributed inverse intervals. Consideration of why the inter-impulse distribution is independent of the distribution of the causative noise suggests two putative interval distributions that do not depend on the assumed noise distribution: the log normal distribution, which is predicated on the assumption that long intervals occur with the joint probability of small input values, and the random walk equation, which is the diffusion equation applied to a random walk model of the impulse generating process. Either of these equations provides a more satisfactory fit to the simulated impulse trains than the hyperbolic normal or hyperbolic gamma distributions. These equations also provide better fits to impulse trains derived from the maintained discharges of ganglion cells in the retinae of cats or goldfish. It is noted that both equations are free from the constraint that the coefficient of variation (CV) have a maximum of unity.(ABSTRACT TRUNCATED AT 250 WORDS)

Linear time-dependent reference intervals where there is measurement error in the time variable-a parametric approach.

PubMed

Gillard, Jonathan

2015-12-01

This article re-examines parametric methods for the calculation of time specific reference intervals where there is measurement error present in the time covariate. Previous published work has commonly been based on the standard ordinary least squares approach, weighted where appropriate. In fact, this is an incorrect method when there are measurement errors present, and in this article, we show that the use of this approach may, in certain cases, lead to referral patterns that may vary with different values of the covariate. Thus, it would not be the case that all patients are treated equally; some subjects would be more likely to be referred than others, hence violating the principle of equal treatment required by the International Federation for Clinical Chemistry. We show, by using measurement error models, that reference intervals are produced that satisfy the requirement for equal treatment for all subjects. © The Author(s) 2011.

The associations of social self-control, personality disorders, and demographics with drug use among high-risk youth.

PubMed

Sussman, Steve; McCuller, William J; Dent, Clyde W

2003-08-01

A 10-item self-report measure of social self-control was examined for its association with substance use, controlling for its associations with 12 personality disorder indices and 4 demographic variables among a sample of 1050 high-risk youth. Social self-control was found to be associated with 30-day cigarette smoking, alcohol use, marijuana use, and hard drug use, controlling for these other variables. The most consistent concurrent predictors of substance use were male gender, antisocial personality disorder, and social self-control. These results highlight the importance of social self-control as a unique concurrent predictor of substance use and suggest that social self-control skill training is relevant in substance abuse prevention programming.

Predictors of neonatal outcome in women with severe preeclampsia or eclampsia between 24 and 33 weeks' gestation.

PubMed

Witlin, A G; Saade, G R; Mattar, F; Sibai, B M

2000-03-01

We sought to characterize predictors of neonatal outcome in women with severe preeclampsia or eclampsia who were delivered of their infants preterm. We performed a retrospective analysis of 195 pregnancies delivered between 24 and 33 weeks' gestation because of severe preeclampsia or eclampsia. Multiple logistic regression and univariate chi(2) analysis were performed for the dependent outcome variables of survival and respiratory distress syndrome by use of independent fetal and maternal variables. A P value of <.05 was considered significant. In the multivariate analysis, respiratory distress syndrome was inversely related to gestational age at delivery (P =.0018) and directly related to cesarean delivery (P =.02), whereas survival was directly related to birth weight (P =.00025). There was no correlation in the multivariate analysis between respiratory distress syndrome or survival and corticosteroid use, composite neonatal morbidity, mean arterial pressure, eclampsia, or abruptio placentae. In the univariate analysis respiratory distress syndrome was associated with cesarean delivery (odds ratio, 7.19; 95% confidence interval, 2. 91-18.32). The incidence of intrauterine growth restriction increased as gestational age advanced. Furthermore, intrauterine growth restriction decreased survival in both the multivariate (P =. 038; odds ratio, 13.2; 95% confidence interval, 1.16-151.8) and univariate (P =.001; odds ratio, 5.88; 95% confidence interval, 1. 81-19.26) analyses. The presence of intrauterine growth restriction adversely affected survival independently of other variables. Presumed intrauterine stress, as reflected by the severity of maternal disease, did not improve neonatal outcome.

Assessment of Simulated and Aquarius-Observed Sea Surface Salinity Using Salinity Measurements in Dry Tortugas National Park, Florida, U.S.A.: Application for Pseudocoral δ18O

NASA Astrophysics Data System (ADS)

Chaichitehrani, N.; DeLong, K. L.

2016-02-01

Salinity plays a critical role in ocean physics thus is a target for paleoclimatologic and paleoceanographic reconstruction. Here we assess the quality of space-borne sea surface salinity (SSS) determinations and simulated SSS versus SSS measurements from an open ocean coral reef site, Dry Tortugas National Park (DTNP). The oxygen isotopic composition of seawater (δ18Osw) is related to SSS, thus SSS can be used to understand δ18Osw variability when measurements of δ18Osw are sparse. In marine carbonates such as corals, δ18Ocoral varies with temperature and δ18Osw creating a bivariate system, which is difficult to calibrate with two variables. Accurate determinations of SSS from satellites and simulations can be substituted for local SSS, converted to δ18Osw, in bivariate forward models to estimate δ18Ocoral or pseudocoral thus improving calibrations of δ18Ocoral for locations and time intervals without in situ observations. Monthly and daily Aquarius-retrieved SSS data Level-3 (Official Version 3.0) with spatial resolution are compared with local SSS in DTNP obtained from Water Quality Monitoring Project for the Florida Keys National Marine Sanctuary and southwest Florida shelf, which includes DTNP, for the concurrent interval from 2011-2014. Our statistical analysis shows a satisfactory agreement between daily Aquarius SSS and local SSS (r2=0.68; RMSE=0.24 psu). Additional SSS data are obtained from the National Data Buoy Center DRYF1 station in DTNP. Monthly-simulated SSS (Global Ocean Physics Reanalysis GLORYS2V3) obtained from the MyOcean WebPortal compares relatively well with DRYF1 monthly SSS data (r2=0.68; RMSE=0.35 psu) for the earlier interval from 1998-2002. Our analysis indicates that Aquarius-retrieved and simulated SSS can be utilized as a substitute for local SSS in bivariate forward models to calculate pseudocoral δ18Ocoral as well as forward models other marine carbonates for locations without SSS observations.

Nickel-regulated heart rate variability: The roles of oxidative stress and inflammation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chuang, Hsiao-Chi, E-mail: r92841005@ntu.edu.tw; Division of Pulmonary Medicine, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan; Hsueh, Tzu-Wei, E-mail: r95841015@ntu.edu.tw

Heart rate variability (HRV) has been reported to be a putative marker of cardiac autonomic imbalance caused by exposure to ambient particulate matter (PM). Our objective in this study was to determine the effects on HRV from exposure to nickel, an important chemical component of ambient PM that results in oxidative stress and inflammation. HRV data were collected for 72 h before lung exposure (baseline) and 72 h after intratracheal exposure (response) to nickel sulphate (NiSO{sub 4}; 526 μg) in Wistar Kyoto (WKY) and spontaneously hypertensive (SH) rats. The antioxidant N-acetyl-L-cysteine (NAC) and the anti-inflammatory celecoxib were intraperitoneally injected tomore » examine post-exposure oxidative and inflammatory responses. Self-controlled experiments examined the effects of NiSO{sub 4} exposure on average normal-to-normal intervals (ANN), natural logarithm-transformed standard deviation of the normal-to-normal intervals (LnSDNN) and root mean square of successive differences of adjacent normal-to-normal intervals (LnRMSSD); the resulting data were sequentially analysed using the generalised estimating equation model. HRV effects on NiSO{sub 4}-exposed SH rats were greater than those on NiSO{sub 4}-exposed WKY rats. After adjusted the HRV responses in the WKY rats as control, ANN and LnRMSSD were found to be quadratically increased over 72 h after exposure to NiSO{sub 4}. Both NAC and celecoxib mitigated the NiSO{sub 4}-induced alterations in HRV during the exposure period. The results suggest that concurrent Ni-induced oxidative stress and inflammatory responses play important roles in regulating HRV. These findings help bridge the gap between epidemiological and clinical studies on the plausible mechanisms of the cardiovascular consequences induced by chemical components in ambient PM. -- Highlights: ► To determine the effects on HRV from exposure to nickel. ► ANN and LnRMSSD were found to be quadratically increased after exposure to Ni. ► NAC and celecoxib mitigated the Ni-induced alterations in HRV. ► Ni-induced oxidative stress and inflammation play the roles in regulating HRV.« less

Trends in Concurrency, Polygyny, and Multiple Sex Partnerships During a Decade of Declining HIV Prevalence in Eastern Zimbabwe

PubMed Central

Eaton, Jeffrey W.; Takavarasha, Felicia R.; Schumacher, Christina M.; Mugurungi, Owen; Garnett, Geoffrey P.; Nyamukapa, Constance; Gregson, Simon

2014-01-01

Background. Observed declines in the prevalence of human immunodeficiency virus (HIV) infection in Zimbabwe have been attributed to population-level reductions in sexual partnership numbers. However, it remains unknown whether certain types of sex partnerships were more important to this decline. Particular debate surrounds the epidemiologic importance of polygyny (the practice of having multiple wives). Methods. We analyze changes in reported multiple partnerships, nonmarital concurrency, and polygyny in eastern Zimbabwe during a period of declining HIV prevalence, from 1998 to 2011. Trends are reported for adult men (age, 17–54 years) and women (age, 15–49 years) from 5 survey rounds of the Manicaland HIV/STD Prevention Project, a general-population open cohort study. Results. At baseline, 34.2% of men reported multiple partnerships, 11.9% reported nonmarital concurrency, and 4.6% reported polygyny. Among women, 4.6% and 1.8% reported multiple partnerships and concurrency, respectively. All 3 partnership indicators declined by similar relative amounts (around 60%–70%) over the period. Polygyny accounted for around 25% of male concurrency. Compared with monogamously married men, polygynous men reported higher levels of subsequent divorce/separation (adjusted relative risk [RR], 2.92; 95% confidence interval [CI], 1.87–4.55) and casual sex partnerships (adjusted RR, 1.63; 95% CI, 1.41–1.88). Conclusions. No indicator clearly dominated declines in partnerships. Polygyny was surprisingly unstable and, in this population, should not be considered a safe form of concurrency. PMID:25381376

The contribution of suggestibility and expectation to placebo analgesia phenomenon in an experimental setting.

PubMed

De Pascalis, Vilfredo; Chiaradia, Carmela; Carotenuto, Eleonora

2002-04-01

This study reports how placebo analgesia was produced by conditioning whereby the intensity of electric stimulation was surreptitiously reduced in order to examine the contribution of psychological factors of suggestibility and expectancy on placebo analgesia. This strategy was used in order to manipulate expectancy for pain reduction. The magnitudes of the placebo effects were estimated after a manipulation procedure and during experimental trials in which stimulus intensities were reset to original baseline levels. Individual differences in suggestibility, verbal expectancy for drug efficacy and manipulation procedure for pain reduction were tested as possible mediators of placebo analgesia. The following dependent variables were measured: (a) subjective expectancy for drug efficacy in pain relief, (b) expected pain intensity and unpleasantness, (c) concurrent pain intensity and unpleasantness and (d) remembered pain intensity and unpleasantness. Statistically significant placebo effects on sensory and affective measures of pain were obtained independently of the extent of the surreptitious lowering of stimulus strength during manipulation trials. The pairing of placebo administration with painful stimulation was sufficient to produce a generalized placebo analgesic effect. However, verbal expectancy for drug efficacy and individual differences in suggestibility were found to contribute significantly to the magnitude of placebo analgesia. The highest placebo effect was shown by the most pronounced reductions in pain ratings in highly suggestible subjects who received suggestions presumed to elicit high expectancy for drug efficacy. The results also demonstrated that placebo effects established on remembered pain were at least twice as great as those obtained on concurrent placebo effects. This was mainly because baseline pain was remembered as being much more intense than it really was. Moreover, remembered placebo effects, like the concurrent placebo effects, were highly correlated with expected pain scores obtained just after manipulation trials. These results indicate that multiple factors contribute to the placebo effect, including suggestibility, expectancy and conditioning, and that the judgement of placebo analgesia is critically determined by whether pain relief is assessed concurrently or after treatment.

Dose equations for shift-variant CT acquisition modes using variable pitch, tube current, and aperture, and the meaning of their associated CTDI{sub vol}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dixon, Robert L., E-mail: rdixon@wfubmc.edu; Boone, John M.; Kraft, Robert A.

2014-11-01

Purpose: With the increasing clinical use of shift-variant CT protocols involving tube current modulation (TCM), variable pitch or pitch modulation (PM), and variable aperture a(t), the interpretation of the scanner-reported CTDI{sub vol} is called into question. This was addressed for TCM in their previous paper published by Dixon and Boone [Med. Phys. 40, 111920 (14pp.) (2013)] and is extended to PM and concurrent TCM/PM as well as variable aperture in this work. Methods: Rigorous convolution equations are derived to describe the accumulated dose distributions for TCM, PM, and concurrent TCM/PM. A comparison with scanner-reported CTDI{sub vol} formulae clearly identifies themore » source of their differences with the traditional CTDI{sub vol}. Dose distribution simulations using the convolution are provided for a variety of TCM and PM scenarios including a helical shuttle used for perfusion studies (as well as constant mA)—all having the same scanner-reported CTDI{sub vol}. These new convolution simulations for TCM are validated by comparison with their previous discrete summations. Results: These equations show that PM is equivalent to TCM if the pitch variation p(z) is proportional to 1/i(z), where i(z) is the local tube current. The simulations show that the local dose at z depends only weakly on the local tube current i(z) or local pitch p(z) due to scatter from all other locations along z, and that the “local CTDI{sub vol}(z)” or “CTDI{sub vol} per slice” do not represent a local dose but rather only a relative i(z) or p(z). The CTDI-paradigm does not apply to shift-variant techniques and the scanner-reported CTDI{sub vol} for the same lacks physical significance and relevance. Conclusions: While the traditional CTDI{sub vol} at constant tube current and pitch conveys useful information (the peak dose at the center of the scan length), CTDI{sub vol} for shift-variant techniques (TCM or PM) conveys no useful information about the associated dose distribution it purportedly represents. On the other hand, the total energy absorbed E (“integral dose”) as well as its surrogate DLP remain robust (invariant) with respect to shift-variance, depending only on the total mAs = 〈i〉t{sub 0} accumulated during the total beam-on time t{sub 0} and aperture a, where 〈i〉 is the average current.« less

A comparative pH-dissolution profile study of selected commercial levothyroxine products using inductively coupled plasma mass spectrometry.

PubMed

Pabla, Dimple; Akhlaghi, Fatemeh; Zia, Hossein

2009-05-01

Levothyroxine (T4) is a narrow therapeutic index drug with classic bioequivalence problem between various available products. Dissolution of a drug is a crucial step in its oral absorption and bioavailability. The dissolution of T4 from three commercial solid oral dosage forms: Synthroid (SYN), generic levothyroxine sodium by Sandoz Inc. (GEN) and Tirosint (TIR) was studied using a sensitive ICP-MS assay. All the three products showed variable and pH-dependent dissolution behaviors. The absence of surfactant from the dissolution media decreased the percent T4 dissolved for all the three products by 26-95% (at 30 min). SYN dissolution showed the most pH dependency, whereas GEN and TIR showed the fastest and highest dissolution, respectively. TIR was the most consistent one, and was minimally affected by pH and/or by the presence of surfactant. Furthermore, dissolution of T4 decreased considerably with increase in the pH, which suggests a possible physical interaction in patients concurrently on T4 and gastric pH altering drugs, such as proton pump inhibitors. Variable dissolution of T4 products can, therefore, impact the oral absorption and bioavailability of T4 and may result in bioequivalence problems between various available products.

High Cryptococcal Antigen Titers in Blood Are Predictive of Subclinical Cryptococcal Meningitis Among Human Immunodeficiency Virus-Infected Patients.

PubMed

Wake, Rachel M; Britz, Erika; Sriruttan, Charlotte; Rukasha, Ivy; Omar, Tanvier; Spencer, David C; Nel, Jeremy S; Mashamaite, Sello; Adelekan, Adeboye; Chiller, Tom M; Jarvis, Joseph N; Harrison, Thomas S; Govender, Nelesh P

2018-02-10

High mortality rates among asymptomatic cryptococcal antigen (CrAg)-positive patients identified through CrAg screening, despite preemptive fluconazole treatment, may be due to undiagnosed cryptococcal meningitis. Symptoms were reviewed in CrAg-positive patients identified by screening 19233 individuals with human immunodeficiency virus infection and CD4 cell counts <100/µL at 17 clinics and 3 hospitals in Johannesburg from September 2012 until September 2015, and at 2 hospitals until June 2016. Cerebrospinal fluid samples from 90 of 254 asymptomatic patients (35%) and 78 of 173 (45%) with headache only were analyzed for cryptococcal meningitis, considered present if Cryptococcus was identified by means of India ink microscopy, culture, or CrAg test. CrAg titers were determined with stored blood samples from 62 of these patients. The associations between blood CrAg titer, concurrent cryptococcal meningitis, and mortality rate were assessed. Cryptococcal meningitis was confirmed in 34% (95% confidence interval, 25%-43%; 31 of 90) of asymptomatic CrAg-positive patients and 90% (81%-96%; 70 of 78) with headache only. Blood CrAg titer was significantly associated with concurrent cryptococcal meningitis in asymptomatic patients (P < .001) and patients with headache only (P = .003). The optimal titer for predicting cryptococcal meningitis was >160 (sensitivity, 88.2%; specificity, 82.1%); the odds ratio for concurrent cryptococcal meningitis was 34.5 (95% confidence interval, 8.3-143.1; P < .001). About a third of asymptomatic CrAg-positive patients have concurrent cryptococcal meningitis. More effective clinical assessment strategies and antifungal regimens are required for CrAg-positive patients, including investigation for cryptococcal meningitis irrespective of symptoms. Where it is not possible to perform lumbar punctures in all CrAg-positive patients, blood CrAg titers should be used to target those most at risk of cryptococcal meningitis. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

Satellite cell response to concurrent resistance exercise and high-intensity interval training in sedentary, overweight/obese, middle-aged individuals.

PubMed

Pugh, Jamie K; Faulkner, Steve H; Turner, Mark C; Nimmo, Myra A

2018-02-01

Sarcopenia can begin from the 4-5th decade of life and is exacerbated by obesity and inactivity. A combination of resistance exercise (RE) and endurance exercise is recommended to combat rising obesity and inactivity levels. However, work continues to elucidate whether interference in adaptive outcomes occur when RE and endurance exercise are performed concurrently. This study examined whether a single bout of concurrent RE and high-intensity interval training (HIIT) alters the satellite cell response following exercise compared to RE alone. Eight sedentary, overweight/obese, middle-aged individuals performed RE only (8 × 8 leg extensions at 70% 1RM), or RE + HIIT (10 × 1 min at 90% HR max on a cycle ergometer). Muscle biopsies were collected from the vastus lateralis before and 96 h after the RE component to determine muscle fiber type-specific total (Pax7 + cells) and active (MyoD + cells) satellite cell number using immunofluorescence microscopy. Type-I-specific Pax7 + (P = 0.001) cell number increased after both exercise trials. Type-I-specific MyoD + (P = 0.001) cell number increased after RE only. However, an elevated baseline value in RE + HIIT compared to RE (P = 0.046) was observed, with no differences between exercise trials at 96 h (P = 0.21). Type-II-specific Pax7 + and MyoD + cell number remained unchanged after both exercise trials (all P ≥ 0.13). Combining a HIIT session after a single bout of RE does not interfere with the increase in type-I-specific total, and possibly active, satellite cell number, compared to RE only. Concurrent RE + HIIT may offer a time-efficient way to maximise the physiological benefits from a single bout of exercise in sedentary, overweight/obese, middle-aged individuals.

Concurrent Chemo-Radiation With or Without Induction Gemcitabine, Carboplatin, and Paclitaxel: A Randomized, Phase 2/3 Trial in Locally Advanced Nasopharyngeal Carcinoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tan, Terence, E-mail: trdtwk@nccs.com.sg; Lim, Wan-Teck; Fong, Kam-Weng

Purpose: To compare survival, tumor control, toxicities, and quality of life of patients with locally advanced nasopharyngeal carcinoma (NPC) treated with induction chemotherapy and concurrent chemo-radiation (CCRT), against CCRT alone. Patients and Methods: Patients were stratified by N stage and randomized to induction GCP (3 cycles of gemcitabine 1000 mg/m{sup 2}, carboplatin area under the concentration-time-curve 2.5, and paclitaxel 70 mg/m{sup 2} given days 1 and 8 every 21 days) followed by CCRT (radiation therapy 69.96 Gy with weekly cisplatin 40 mg/m{sup 2}), or CCRT alone. The accrual of 172 was planned to detect a 15% difference in 5-year overall survival (OS) with a 5%more » significance level and 80% power. Results: Between September 2004 and August 2012, 180 patients were accrued, and 172 (GCP 86, control 86) were analyzed by intention to treat. There was no significant difference in OS (3-year OS 94.3% [GCP] vs 92.3% [control]; hazard ratio 1.05; 1-sided P=.494]), disease-free survival (hazard ratio 0.77, 95% confidence interval 0.44-1.35, P=.362), and distant metastases–free survival (hazard ratio 0.80, 95% confidence interval 0.38-1.67, P=.547) between the 2 arms. Treatment compliance in the induction phase was good, but the relative dose intensity for concurrent cisplatin was significantly lower in the GCP arm. Overall, the GCP arm had higher rates of grades 3 and 4 leukopenia (52% vs 37%) and neutropenia (24% vs 12%), but grade 3 and 4 acute radiation toxicities were not statistically different between the 2 arms. The global quality of life scores were comparable in both arms. Conclusion: Induction chemotherapy with GCP before concurrent chemo-irradiation did not improve survival in locally advanced NPC.« less

On the internal target model in a tracking task

NASA Technical Reports Server (NTRS)

Caglayan, A. K.; Baron, S.

1981-01-01

An optimal control model for predicting operator's dynamic responses and errors in target tracking ability is summarized. The model, which predicts asymmetry in the tracking data, is dependent on target maneuvers and trajectories. Gunners perception, decision making, control, and estimate of target positions and velocity related to crossover intervals are discussed. The model provides estimates for means, standard deviations, and variances for variables investigated and for operator estimates of future target positions and velocities.

Psychosocial Factors Influencing Smokeless Tobacco Use by Teenage Military Dependents

DTIC Science & Technology

1994-01-01

age and grade Demographics both show strong bivariate relationships with the outcome MALE-male gender measures, we selected to use only one of these...a positive sign indicating a direct relation- no impact for either gender . Attitude and other tobacco influ- ship and a negative sign an inverse...by both genders . nlficant. However, if the interval includes one but is highly For both genders , the strongest explanatory variable for trial skewed

Amphibian breeding phenology and reproductive outcome: an examination using terrestrial and aquatic sampling

Treesearch

C.H. Greenberg; S.A. Johnson; R. Owen; A. Storfer

2017-01-01

Worldwide amphibian declines highlight the need for programs that monitor species presence and track population trends. We sampled larval amphibians with a box trap at 3-week intervals for 23 months in eight wetlands, and concurrently trapped adults and juveniles with drift fences, to examine spatiotemporal patterns of tadpole occurrence; explore relationships between...

Concurrent infections with Cryptosporidium spp., Giardia duodenalis, Enterocytozoon bieneusi, and Blastocystis spp. in naturally infected dairy cattle from birth to two years of age

USDA-ARS?s Scientific Manuscript database

Fecal specimens were collected directly at weekly and then monthly intervals from each of 30 dairy calves from birth to 24 months to determine the prevalence and age distribution of Cryptosporidium spp., Giardia duodenalis assemblages, Enterocytozoon bieneusi genotypes, and Blastocystis spp subtypes...

Selection Dynamics in Joint Matching to Rate and Magnitude of Reinforcement

ERIC Educational Resources Information Center

McDowell, J. J.; Popa, Andrei; Calvin, Nicholas T.

2012-01-01

Virtual organisms animated by a selectionist theory of behavior dynamics worked on concurrent random interval schedules where both the rate and magnitude of reinforcement were varied. The selectionist theory consists of a set of simple rules of selection, recombination, and mutation that act on a population of potential behaviors by means of a…

Magno and Parvo Stimuli Affect Illusory Directional Hearing in Normal and Dyslexic Readers

ERIC Educational Resources Information Center

Li, Winston; Meekins, Kelsey; Schirillo, James

2012-01-01

In an experimental paradigm adapted from Hari (1995), forty observers listened via headphones to 8 binaural clicks: 4 left-ear leading followed by 4 right-ear leading with either 38 or 140 ms interstimulus intervals (ISIs). Concurrently, they viewed either foveal or peripheral visual stimuli designed to activate either the parvocellular or…

Microbial Community Analysis of Naturally Durable Wood in an Above Ground Field Test

Treesearch

G.T. Kirker; S.V. Diehl; P.K. Lebow

2014-01-01

This paper presents preliminary results of an above ground field test wherein eight naturally durable wood species were exposed concurrently at two sites in North America. Surface samples were taken at regular intervals from non-durable controls and compared to their more durable counterparts. Terminal Restriction Fragment Length Polymorphism was performed to...

Local expression of global forcing factors in Lower Cretaceous, Aptian carbon isotope segment C5: El Pujal Section, Organya Basin, Catalunya, Spain.

NASA Astrophysics Data System (ADS)

Socorro, J.; Maurrasse, F. J.

2017-12-01

During the Aptian, the semi-restricted Organya Basin accumulated sediments under quasi-continuous dysoxic conditions [1]. High resolution stable carbon isotope (δ13Corg) values for 71.27 m of interbedded limestones, argillaceous limestones and marlstones of the El Pujal sequence show relatively small variability (1.65‰) fluctuating between -25.09‰ and -23.44‰ with an average of -24.02‰. This pattern is consistent with values reported for other Tethyan sections for carbon isotope segment C5 [2]. The geochemical and petrographic results of the sequence, reveal periodic enrichment of redox sensitive trace elements (V, Cr, Co, Ni, Cu, Mo, U), biolimiting (P, Fe) and major elements (Al, Si, Ti) at certain levels concurrent with episodes of enhanced organic carbon preservation (TOC). Inorganic carbonate (TIC) dilution due to significant clay fluxes is also evident along these intervals as illustrated by the strong negative correlation with Al (r = -0.91). Microfacies characterized by higher pyrite concentration, impoverished benthic fauna and lower degree of bioturbation index (3) are in accord with geochemical proxies. When combined, these results suggest recurrent intermittent dysoxic conditions associated with episodic increases of terrigenous supplies by riverine fluxes, which are in agreement with results reported for the basal segment of the section (0-13.77m) [3]. Concurrently, δ13Corg values show a positive correlation with TIC (r = 0.50) and a negative correlation with TOC (r = -0.46), thus showing more negative values corresponding with intervals of highest terrestrial influences, which were previously correlated with higher inputs of higher chain (>nC25) n-alkanes [3]. Hence, the results highlight the local expression of the δ13Corg signal related to higher inputs of terrestrial vegetation linked with lower δ13Corg values modulating the global signature of segment C5. References: [1] Sanchez-Hernandez & Maurrasse, 2016. Palaeo3 441; [2] Menegatti et al., 1998. Paleoceanography 13 530-545; [3] Socorro & Maurrasse, 2016. AGU Fall Meeting Abstracts

Generalized concurrence measure for faithful quantification of multiparticle pure state entanglement using Lagrange's identity and wedge product

NASA Astrophysics Data System (ADS)

Bhaskara, Vineeth S.; Panigrahi, Prasanta K.

2017-05-01

Concurrence, introduced by Hill and Wootters (Phys Rev Lett 78:5022, 1997), provides an important measure of entanglement for a general pair of qubits that is faithful: strictly positive for entangled states and vanishing for all separable states. Such a measure captures the entire content of entanglement, providing necessary and sufficient conditions for separability. We present an extension of concurrence to multiparticle pure states in arbitrary dimensions by a new framework using the Lagrange's identity and wedge product representation of separability conditions, which coincides with the "I-concurrence" of Rungta et al. (Phys Rev A 64:042315, 2001) who proposed by extending Wootters's spin-flip operator to a so-called universal inverter superoperator. Our framework exposes an inherent geometry of entanglement and may be useful for the further extensions to mixed and continuous variable states.

Effects of practice on variability in an isochronous serial interval production task: asymptotical levels of tapping variability after training are similar to those of musicians.

PubMed

Madison, Guy; Karampela, Olympia; Ullén, Fredrik; Holm, Linus

2013-05-01

Timing permeates everyday activities such as walking, dancing and music, yet the effect of short-term practice in this ubiquitous activity is largely unknown. In two training experiments involving sessions spread across several days, we examined short-term practice effects on timing variability in a sequential interval production task. In Experiment 1, we varied the mode of response (e.g., drumstick and finger tapping) and the level of sensory feedback. In Experiment 2 we varied the interval in 18 levels ranging from 500 ms to 1624 ms. Both experiments showed a substantial decrease in variability within the first hour of practice, but little thereafter. This effect was similar across mode of response, amount of feedback, and interval duration, and was manifested as a reduction in both local variability (between neighboring intervals) and drift (fluctuation across multiple intervals). The results suggest mainly effects on motor implementation rather than on cognitive timing processes, and have methodological implications for timing studies that have not controlled for practice. Copyright © 2013 Elsevier B.V. All rights reserved.

A spatially collocated sound thrusts a flash into awareness

PubMed Central

Aller, Máté; Giani, Anette; Conrad, Verena; Watanabe, Masataka; Noppeney, Uta

2015-01-01

To interact effectively with the environment the brain integrates signals from multiple senses. It is currently unclear to what extent spatial information can be integrated across different senses in the absence of awareness. Combining dynamic continuous flash suppression (CFS) and spatial audiovisual stimulation, the current study investigated whether a sound facilitates a concurrent visual flash to elude flash suppression and enter perceptual awareness depending on audiovisual spatial congruency. Our results demonstrate that a concurrent sound boosts unaware visual signals into perceptual awareness. Critically, this process depended on the spatial congruency of the auditory and visual signals pointing towards low level mechanisms of audiovisual integration. Moreover, the concurrent sound biased the reported location of the flash as a function of flash visibility. The spatial bias of sounds on reported flash location was strongest for flashes that were judged invisible. Our results suggest that multisensory integration is a critical mechanism that enables signals to enter conscious perception. PMID:25774126

Stroop proactive control and task conflict are modulated by concurrent working memory load.

PubMed

Kalanthroff, Eyal; Avnit, Amir; Henik, Avishai; Davelaar, Eddy J; Usher, Marius

2015-06-01

Performance on the Stroop task reflects two types of conflict-informational (between the incongruent word and font color) and task (between the contextually relevant color-naming task and the irrelevant, but automatic, word-reading task). According to the dual mechanisms of control theory (DMC; Braver, 2012), variability in Stroop performance can result from variability in the deployment of a proactive task-demand control mechanism. Previous research has shown that when proactive control (PC) is diminished, both increased Stroop interference and a reversed Stroop facilitation (RF) are observed. Although the current DMC model accounts for the former effect, it does not predict the observed RF, which is considered to be behavioral evidence for task conflict in the Stroop task. Here we expanded the DMC model to account for Stroop RF. Assuming that a concurrent working memory (WM) task reduces PC, we predicted both increased interference and an RF. Nineteen participants performed a standard Stroop task combined with a concurrent n-back task, which was aimed at reducing available WM resources, and thus overloading PC. Although the results indicated common Stroop interference and facilitation in the low-load condition (zero-back), in the high-load condition (two-back), both increased Stroop interference and RF were observed, consistent with the model's prediction. These findings indicate that PC is modulated by concurrent WM load and serves as a common control mechanism for both informational and task Stroop conflicts.

Introducing the Event Related Fixed Interval Area (ERFIA) Multilevel Technique: a Method to Analyze the Complete Epoch of Event-Related Potentials at Single Trial Level

PubMed Central

Vossen, Catherine J.; Vossen, Helen G. M.; Marcus, Marco A. E.; van Os, Jim; Lousberg, Richel

2013-01-01

In analyzing time-locked event-related potentials (ERPs), many studies have focused on specific peaks and their differences between experimental conditions. In theory, each latency point after a stimulus contains potentially meaningful information, regardless of whether it is peak-related. Based on this assumption, we introduce a new concept which allows for flexible investigation of the whole epoch and does not primarily focus on peaks and their corresponding latencies. For each trial, the entire epoch is partitioned into event-related fixed-interval areas under the curve (ERFIAs). These ERFIAs, obtained at single trial level, act as dependent variables in a multilevel random regression analysis. The ERFIA multilevel method was tested in an existing ERP dataset of 85 healthy subjects, who underwent a rating paradigm of 150 painful and non-painful somatosensory electrical stimuli. We modeled the variability of each consecutive ERFIA with a set of predictor variables among which were stimulus intensity and stimulus number. Furthermore, we corrected for latency variations of the P2 (260 ms). With respect to known relationships between stimulus intensity, habituation, and pain-related somatosensory ERP, the ERFIA method generated highly comparable results to those of commonly used methods. Notably, effects on stimulus intensity and habituation were also observed in non-peak-related latency ranges. Further, cortical processing of actual stimulus intensity depended on the intensity of the previous stimulus, which may reflect pain-memory processing. In conclusion, the ERFIA multilevel method is a promising tool that can be used to study event-related cortical processing. PMID:24224018

Effect of Spacecraft Environmental Variables on the Flammability of Fire Resistant Fabrics

NASA Astrophysics Data System (ADS)

Osorio, A. F.; Fernandez-Pello, C.; Takahashi, S.; Rodriguez, J.; Urban, D. L.; Ruff, G.

2012-01-01

Fire resistant fabrics are used for firefighter, racecar drivers as well as astronaut suits. However, their fire resistant characteristics depend on the environment conditions and require study. Particularly important is the response of these fabrics to elevated oxygen concentration environments and radiant heat from a source such as an adjacent fire. In this work, experiments using two fire resistant fabrics were conducted to study the effect of oxygen concentration, external radiant flux and oxidizer flow velocity in concurrent flame spread. Results show that for a given fabric the minimum oxygen concentration for flame spread depends strongly on the magnitude of the external radiant flux. At increased oxygen concentrations the external radiant flux required for flame spread decreases. Oxidizer flow velocity influences the external radiant flux only when the convective heat flux from the flame has similar values to the external radiant flux. The results of this work provide further understanding of the flammability characteristics of fire resistant fabrics in environments similar to those of future spacecrafts.

The pattern of physical comorbidity and the psychosocial determinants of depression: a prospective cohort study on a representative sample of family practice attendees in Slovenia.

PubMed

Selič, Polona; Svab, Igor; Rifel, Janez; Pavlič, Danica Rotar; Cerne, Anja; King, Michael; Nazareth, Irwin

2011-09-01

Objectives This study aims to present the patterns of physical comorbidity in depressed patients and factors strongly associated with depression in a representative sample of Slovenian family practice attendees.Methods Medical data was obtained for 911 general practice attendees. Of them, 221 (24.3%) were diagnosed as depressed. The depressive states of the subjects were evaluated using the Composite International Diagnostic Interview (CIDI). Physical comorbidity was assessed with a questionnaire covering the most common health problems in the Slovenian adult population. Several psycho-social factors were also analysed.Results Those variables significantly related to ICD depression were included in multivariate binary logistic regression analysis, adjusted by age, gender and education. The calculation included the chi-square, odds ratio (OR) with confidence interval (95% CI) and P-value. A P-value < 0.05 was marked as statistically significant.Conclusions There was no significant difference in the number of concurrent chronic diseases in depressed and non-depressed subjects. The risk of depression was increased by the presence of several concomitant factors. The burden of somatic co-morbidity was shown to be smaller than the impact of psychosocial determinants, which also acted as protective factors: the feeling of safety at home and the absence of problems in intimate relationships. The abuse of alcohol and drugs by a family member and current poor financial situation were strongly associated with depression. The impact of concurrent incontinence and chronic bowel disease was also important, though somewhat weaker.

Choice with frequently changing food rates and food ratios.

PubMed

Baum, William M; Davison, Michael

2014-03-01

In studies of operant choice, when one schedule of a concurrent pair is varied while the other is held constant, the constancy of the constant schedule may exert discriminative control over performance. In our earlier experiments, schedules varied reciprocally across components within sessions, so that while food ratio varied food rate remained constant. In the present experiment, we held one variable-interval (VI) schedule constant while varying the concurrent VI schedule within sessions. We studied five conditions, each with a different constant left VI schedule. On the right key, seven different VI schedules were presented in seven different unsignaled components. We analyzed performances at several different time scales. At the longest time scale, across conditions, behavior ratios varied with food ratios as would be expected from the generalized matching law. At shorter time scales, effects due to holding the left VI constant became more and more apparent, the shorter the time scale. In choice relations across components, preference for the left key leveled off as the right key became leaner. Interfood choice approximated strict matching for the varied right key, whereas interfood choice hardly varied at all for the constant left key. At the shortest time scale, visit patterns differed for the left and right keys. Much evidence indicated the development of a fix-and-sample pattern. In sum, the procedural difference made a large difference to performance, except for choice at the longest time scale and the fix-and-sample pattern at the shortest time scale. © Society for the Experimental Analysis of Behavior.

A quantitative analysis of sensitivity to the conditioned reinforcing value of terminal-link stimuli in a concurrent-chains schedule.

PubMed Central

Omino, T

1993-01-01

Pigeons were exposed to a concurrent-chains schedule in which a single variable-interval 30-s schedule was used in the initial links and fixed-time schedules were used in the terminal links. Three types of keylight conditions were used in the terminal links. In the first condition, different delays were associated with different keylight stimuli (cued condition). In the second condition, different delays were associated with the same stimulus, either a blackout (uncued blackout condition) or a white key (uncued white condition). Paired values of terminal-link fixed-time schedules differed by a constant ratio of 3:1, while the absolute value of delays was varied from 3 s to 54 s. The results showed that choice proportions for the shorter of two delays increased when the absolute size of the delays was increased for all keylight conditions. Further, the choice proportions for the shorter delay increased from the uncued blackout condition, to the uncued white condition, to the cued condition. A modified version of Fantino's (1969) delay-reduction model (expressed as a function relating the response ratio to the delay-reduction ratio) can be applied to these data by showing that sensitivity to delay reduction increased from the uncued blackout condition, to the uncued white condition, to the cued condition. Thus, the present study demonstrated that a modified version of the delay-reduction model can be used to assess quantitative differences in the terminal-link keylight condition in terms of sensitivity to delay reduction (i.e., the conditioned reinforcing value of the terminal-link keylight stimuli). PMID:8283150

Comorbid psychiatric disorders in depressed outpatients: demographic and clinical features.

PubMed

Rush, A John; Zimmerman, Mark; Wisniewski, Stephen R; Fava, Maurizio; Hollon, Steven D; Warden, Diane; Biggs, Melanie M; Shores-Wilson, Kathy; Shelton, Richard C; Luther, James F; Thomas, Brandi; Trivedi, Madhukar H

2005-07-01

This study evaluated the clinical and sociodemographic features associated with various degrees of concurrent comorbidity in adult outpatients with nonpsychotic major depressive disorder (MDD). Outpatients enrolled in the STAR*D trial completed the Psychiatric Diagnostic Screening Questionnaire (PDSQ). An a priori 90% specificity threshold was set for PDSQ responses to ascertain the presence of 11 different concurrent DSM-IV Axis I disorders. Of 1376 outpatients, 38.2% had no concurrent comorbidities, while 25.6% suffered one, 16.1% suffered two, and 20.2% suffered three or more comorbid conditions. Altogether, 29.3% met threshold for social anxiety disorder, 20.8% for generalized anxiety disorder, 18.8% for posttraumatic stress disorder, 12.4% for bulimia, 11.9% for alcohol abuse/dependence, 13.4% for obsessive-compulsive disorder, 11.1% for panic disorder, 9.4% for agoraphobia, 7.3% for drug abuse/dependence, 3.7% for hypochondriasis, and 2.2% for somatoform disorder. Those with more concurrent Axis I conditions had earlier ages at first onset of MDD, longer histories of MDD, greater depressive symptom severity, more general medical comorbidity (even though they were younger than those with fewer comorbid conditions), poorer physical and mental function, health perceptions, and life satisfaction; and were more likely to be seen in primary care settings. Participants had to meet entry criteria for STAR*D. Ascertainment of comorbid conditions was not based on a structured interview. Concurrent Axis I conditions (most often anxiety disorders) are very common with MDD. Greater numbers of concurrent comorbid conditions were associated with increased severity, morbidity, and chronicity of their MDD.

Symmetric co-movement between Malaysia and Japan stock markets

NASA Astrophysics Data System (ADS)

Razak, Ruzanna Ab; Ismail, Noriszura

2017-04-01

The copula approach is a flexible tool known to capture linear, nonlinear, symmetric and asymmetric dependence between two or more random variables. It is often used as a co-movement measure between stock market returns. The information obtained from copulas such as the level of association of financial market during normal and bullish and bearish markets phases are useful for investment strategies and risk management. However, the study of co-movement between Malaysia and Japan markets are limited, especially using copulas. Hence, we aim to investigate the dependence structure between Malaysia and Japan capital markets for the period spanning from 2000 to 2012. In this study, we showed that the bivariate normal distribution is not suitable as the bivariate distribution or to present the dependence between Malaysia and Japan markets. Instead, Gaussian or normal copula was found a good fit to represent the dependence. From our findings, it can be concluded that simple distribution fitting such as bivariate normal distribution does not suit financial time series data, whose characteristics are often leptokurtic. The nature of the data is treated by ARMA-GARCH with heavy tail distributions and these can be associated with copula functions. Regarding the dependence structure between Malaysia and Japan markets, the findings suggest that both markets co-move concurrently during normal periods.

Temporal Variability in the Deglutition Literature

PubMed Central

Molfenter, Sonja M.; Steele, Catriona M.

2013-01-01

A literature review was conducted on temporal measures of swallowing in healthy individuals with the purpose of determining the degree of variability present in such measures within the literature. A total of 46 studies that met inclusion criteria were reviewed. The definitions and descriptive statistics for all reported temporal parameters were compiled for meta-analysis. In total, 119 different temporal parameters were found in the literature. The three most-frequently occurring durational measures were: UES opening, laryngeal closure and hyoid movement. The three most-frequently occurring interval measures were: stage transition duration, pharyngeal transit time and duration from laryngeal closure to UES opening. Subtle variations in operational definitions across studies were noted, making the comparison of data challenging. Analysis of forest plots compiling descriptive statistical data (means and 95% confidence intervals) across studies revealed differing degrees of variability across durations and intervals. Two parameters (UES opening duration and the laryngeal-closure-to-UES-opening interval) demonstrated the least variability, reflected by small ranges for mean values and tight confidence intervals. Trends emerged for factors of bolus size and participant age for some variables. Other potential sources of variability are discussed. PMID:22366761

Single step optimization of manipulator maneuvers with variable structure control

NASA Technical Reports Server (NTRS)

Chen, N.; Dwyer, T. A. W., III

1987-01-01

One step ahead optimization has been recently proposed for spacecraft attitude maneuvers as well as for robot manipulator maneuvers. Such a technique yields a discrete time control algorithm implementable as a sequence of state-dependent, quadratic programming problems for acceleration optimization. Its sensitivity to model accuracy, for the required inversion of the system dynamics, is shown in this paper to be alleviated by a fast variable structure control correction, acting between the sampling intervals of the slow one step ahead discrete time acceleration command generation algorithm. The slow and fast looping concept chosen follows that recently proposed for optimal aiming strategies with variable structure control. Accelerations required by the VSC correction are reserved during the slow one step ahead command generation so that the ability to overshoot the sliding surface is guaranteed.

Concurrent validity of the Alcohol Use Disorders Identification Test (AUDIT) and AUDIT zones in defining levels of severity among out-patients with alcohol dependence in the COMBINE study.

PubMed

Donovan, Dennis M; Kivlahan, Daniel R; Doyle, Suzanne R; Longabaugh, Richard; Greenfield, Shelly F

2006-12-01

To examine among alcohol-dependent out-patient clients the concurrent validity of the Alcohol Use Disorders Identification Test (AUDIT) total score and 'zones' suggested by the World Health Organization for defining levels of severity of alcohol use problems. Participants were classified into AUDIT zones (AUDIT total score = 8-15, 16-19, 20-40) and compared on measures of demographics, treatment goals, alcohol consumption, alcohol-related consequences, severity of dependence, physiological dependence, tolerance, withdrawal and biomarkers of alcohol use. Eleven out-patient academic clinical research centers across the United States. Participants Alcohol dependent individuals (n = 1335) entering out-patient treatment in the Combined Pharmacotherapies and Behavioral Interventions (COMBINE) study. The AUDIT was administered as part of an initial screening. Baseline measures used for concurrent validation included the Structured Clinical Interview for Diagnostic and Statistical Manual, 4th edition (DSM-IV) Disorders, the Alcohol Dependence Scale, the Drinker Inventory of Consequences, the Obsessive-Compulsive Drinking Scale, the University of Rhode Island Change Assessment, the Thoughts about Abstinence Scale, the Form-90, %carbohydrate-deficient transferrin and gamma-glutamyl transferase. Findings Indicators of severity of dependence and alcohol-related problems increased linearly with total score and differed significantly across AUDIT zones. The highest zone, with scores of 20 and above, was markedly different with respect to severity from the other two zones and members of this group endorsed an abstinence goal more strongly. The AUDIT total score is a brief measure that appears to provide an index of severity of dependence in a sample of alcohol-dependent individuals seeking out-patient treatment, extending its potential utility beyond its more traditional role as a screening instrument in general populations.

A critique of the usefulness of inferential statistics in applied behavior analysis

PubMed Central

Hopkins, B. L.; Cole, Brian L.; Mason, Tina L.

1998-01-01

Researchers continue to recommend that applied behavior analysts use inferential statistics in making decisions about effects of independent variables on dependent variables. In many other approaches to behavioral science, inferential statistics are the primary means for deciding the importance of effects. Several possible uses of inferential statistics are considered. Rather than being an objective means for making decisions about effects, as is often claimed, inferential statistics are shown to be subjective. It is argued that the use of inferential statistics adds nothing to the complex and admittedly subjective nonstatistical methods that are often employed in applied behavior analysis. Attacks on inferential statistics that are being made, perhaps with increasing frequency, by those who are not behavior analysts, are discussed. These attackers are calling for banning the use of inferential statistics in research publications and commonly recommend that behavioral scientists should switch to using statistics aimed at interval estimation or the method of confidence intervals. Interval estimation is shown to be contrary to the fundamental assumption of behavior analysis that only individuals behave. It is recommended that authors who wish to publish the results of inferential statistics be asked to justify them as a means for helping us to identify any ways in which they may be useful. PMID:22478304

Technical Note: The Initial Stages of Statistical Data Analysis

PubMed Central

Tandy, Richard D.

1998-01-01

Objective: To provide an overview of several important data-related considerations in the design stage of a research project and to review the levels of measurement and their relationship to the statistical technique chosen for the data analysis. Background: When planning a study, the researcher must clearly define the research problem and narrow it down to specific, testable questions. The next steps are to identify the variables in the study, decide how to group and treat subjects, and determine how to measure, and the underlying level of measurement of, the dependent variables. Then the appropriate statistical technique can be selected for data analysis. Description: The four levels of measurement in increasing complexity are nominal, ordinal, interval, and ratio. Nominal data are categorical or “count” data, and the numbers are treated as labels. Ordinal data can be ranked in a meaningful order by magnitude. Interval data possess the characteristics of ordinal data and also have equal distances between levels. Ratio data have a natural zero point. Nominal and ordinal data are analyzed with nonparametric statistical techniques and interval and ratio data with parametric statistical techniques. Advantages: Understanding the four levels of measurement and when it is appropriate to use each is important in determining which statistical technique to use when analyzing data. PMID:16558489

Parametric methods outperformed non-parametric methods in comparisons of discrete numerical variables.

PubMed

Fagerland, Morten W; Sandvik, Leiv; Mowinckel, Petter

2011-04-13

The number of events per individual is a widely reported variable in medical research papers. Such variables are the most common representation of the general variable type called discrete numerical. There is currently no consensus on how to compare and present such variables, and recommendations are lacking. The objective of this paper is to present recommendations for analysis and presentation of results for discrete numerical variables. Two simulation studies were used to investigate the performance of hypothesis tests and confidence interval methods for variables with outcomes {0, 1, 2}, {0, 1, 2, 3}, {0, 1, 2, 3, 4}, and {0, 1, 2, 3, 4, 5}, using the difference between the means as an effect measure. The Welch U test (the T test with adjustment for unequal variances) and its associated confidence interval performed well for almost all situations considered. The Brunner-Munzel test also performed well, except for small sample sizes (10 in each group). The ordinary T test, the Wilcoxon-Mann-Whitney test, the percentile bootstrap interval, and the bootstrap-t interval did not perform satisfactorily. The difference between the means is an appropriate effect measure for comparing two independent discrete numerical variables that has both lower and upper bounds. To analyze this problem, we encourage more frequent use of parametric hypothesis tests and confidence intervals.

Cognitive complaints correlate with depression rather than concurrent objective cognitive impairment in the SAGE baseline sample

PubMed Central

Zlatar, Zvinka Z.; Moore, Raeanne C.; Palmer, Barton W.; Thompson, Wesley K.; Jeste, Dilip V.

2014-01-01

Objective Whether subjective cognitive complaints are suggestive of depression or concurrent cognitive impairment in older adults without dementia remains unclear. The current study examined this question in a large (N=1,000), randomly-selected community-based sample of adults ages 51-99 without a formal diagnosis of dementia (Successful AGing Evaluation study-SAGE). Methods The modified Telephone Interview for Cognitive Status (TICS-m) measured objective cognitive function, the Cognitive Failures Questionnaire (CFQ) measured subjective cognitive complaints, and the Patient Health Questionnaire (PHQ-9) measured depression. Spearman rho correlations and linear regression models were conducted to examine the relationship among variables in the baseline SAGE sample. Results There was a weak association between TICS-m and CFQ scores (rho= -.12); however a moderate to large association was observed for CFQ and PHQ-9 (rho= .44). Scores on the CFQ were not associated with TICS-m scores (β=-.03, p=.42) after controlling for PHQ-9 and variables of interest, such as age, gender, ethnicity, and physical functioning, while PHQ-9 was significantly associated with CFQ scores (β=.46, p<.001) after controlling for variables of interest. Conclusions Subjective cognitive complaints are more likely related to symptoms of depression rather than concurrent cognitive impairment in a large cross-section of community-dwelling adults without a formal diagnosis of dementia. PMID:24614203

Maturation Modulates Pharyngeal-Stimulus Provoked Pharyngeal and Respiratory Rhythms in Human Infants.

PubMed

Hasenstab, Kathryn A; Sitaram, Swetha; Lang, Ivan M; Shaker, Reza; Jadcherla, Sudarshan R

2018-02-01

Pharyngeal-provocation induced aerodigestive symptoms in infants remain an enigma. Sources of pharyngeal provocation can be anterograde as with feeding, and retrograde as in gastroesophageal reflux. We determined maturational and dose-response effects of targeted pharyngeal-stimulus on frequency, stability, and magnitude of pharyngeal and respiratory waveforms during multiple pharyngeal swallowing responses in preterm-born infants when they were of full-term postmenstrual age (PMA). Eighteen infants (11 male) were studied longitudinally at 39.8 ± 4.8 weeks PMA (time-1) and 44.1 ± 5.8 weeks PMA (time-2). Infants underwent concurrent pharyngo-esophageal manometry, respiratory inductance plethysmography, and nasal airflow thermistor methods to test sensory-motor interactions between the pharynx, esophagus, and airway. Linear mixed models were used and data presented as mean ± SEM or %. Overall, responses to 250 stimuli were analyzed. Of the multiple pharyngeal swallowing responses (n = 160), with maturation (a) deglutition apnea duration decreases (p < 0.01), (b) number of pharyngeal waveform peaks and duration decreases for initial responses (p < 0.01), and subsequent responses have lesser variation and greater stability (p < 0.01). With increment in stimulus volumes we noted (a) increased prevalence (%) of pharyngeal responses (p < 0.05), (b) increased number of pharyngeal peaks (p < 0.05), yet pharyngeal frequency (Hz), variability, and stability remain unaffected (p > 0.05), and (c) respiratory changes were unaffected (p > 0.05). Initial and subsequent pharyngeal responses and respiratory rhythm interactions become more distinct with maturation. Interval oromotor experiences and volume-dependent increase in adaptive responses may be contributory. These mechanisms may be important in modulating and restoring respiratory rhythm normalcy.

Effects of ethanol on cocaine self-administration in monkeys responding under a second-order schedule of reinforcement.

PubMed

John, William S; Nader, Michael A

2017-01-01

Concurrent alcohol use among cocaine abusers is common but the behavioral variables that promote co-abuse are not well understood. The present study examined the effects of intragastric (i.g.) ethanol (EtOH) administration in monkeys responding under a schedule of cocaine reinforcement in which extensive drug seeking was maintained by conditioned stimuli. Four adult male cynomolgus monkeys (Macaca fascicularis) were trained to respond under a second-order fixed-interval (FI) 600s (fixed-ratio (FR) 30:S) schedule of cocaine (0.003-0.56mg/kg/injection) presentation. Sessions ended after 5 injections or 90min had elapsed. Different EtOH doses (0.5-2.0g/kg, i.g.) were administered 30min before the session, typically on Tuesdays and Fridays. Blood ethanol concentrations (BECs) were also assessed. Pattern of FI responding was assessed by determining quarter-life (QL) values. Cocaine self-administration was characterized as an inverted U-shaped function of dose; QL values increased monotonically with dose. EtOH pretreatments dose-dependently decreased self-administration at several cocaine doses in 3 of 4 monkeys. In one animal, EtOH increased low-dose cocaine-maintained responding. For all monkeys, QL values were increased by EtOH when low- and high-cocaine doses were self-administered, suggesting additive effects of EtOH and cocaine. Furthermore, BECs were not altered following cocaine self-administration. The reductions in cocaine self-administration and the increases in QL values following EtOH, suggest that EtOH was enhancing cocaine-related conditioned reinforcement. A better understanding of the behavioral mechanisms that mediate the co-abuse of alcohol and cocaine will lead to improved treatments for both drugs. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Child Care Instability and Maternal Depressive Symptoms: Exploring New Avenues for Supporting Maternal Mental Health.

PubMed

Johnson, Anna D; Padilla, Christina M

2018-05-28

We investigate links between child-care experiences - specifically care instability and mother's perceptions of care access - and maternal depressive symptoms, in an effort to illuminate policy-amenable mechanisms through which child-care experiences can support maternal mental health. Data come from the nationally representative Early Childhood Longitudinal Study - Birth Cohort (ECLS-B). We use regression models with lagged dependent variables to estimate associations between aspects of child-care instability and perceptions of care availability, and maternal depressive symptoms. We do so on the full sample and then on subgroups of mothers for whom child-care instability may be especially distressing: mothers who are low-income, working, single, or non-native speakers of English. Child-care instability - length in months in the longest arrangement, and number of arrangements - was not associated with maternal depressive symptoms. However, mothers' perception of having good choices for care was associated with a reduced likelihood of clinical depressive symptomology, even after controlling for prior depressive symptoms and concurrent parenting stress; this latter association was observed both in the full sample (Adjusted Odds Ratio [AOR]=0.77; 95% Confidence Interval [CI]=0.63-0.96) and among subgroups of employed mothers (AOR=0.71; CI=0.57-0.87) and single mothers (AOR=0.72; CI=0.52-0.99). Although dimensions of care instability did not associate with maternal depressive symptoms, mothers' perceptions of available care options, did. If replicated, findings would highlight a previously unconsidered avenue - increasing care accessibility and awareness of available options - for promoting maternal mental health in a population likely to experience depression but unlikely to be treated. Copyright © 2018. Published by Elsevier Inc.

Land use compounds habitat losses under projected climate change in a threatened California ecosystem.

PubMed

Riordan, Erin Coulter; Rundel, Philip W

2014-01-01

Given the rapidly growing human population in mediterranean-climate systems, land use may pose a more immediate threat to biodiversity than climate change this century, yet few studies address the relative future impacts of both drivers. We assess spatial and temporal patterns of projected 21(st) century land use and climate change on California sage scrub (CSS), a plant association of considerable diversity and threatened status in the mediterranean-climate California Floristic Province. Using a species distribution modeling approach combined with spatially-explicit land use projections, we model habitat loss for 20 dominant shrub species under unlimited and no dispersal scenarios at two time intervals (early and late century) in two ecoregions in California (Central Coast and South Coast). Overall, projected climate change impacts were highly variable across CSS species and heavily dependent on dispersal assumptions. Projected anthropogenic land use drove greater relative habitat losses compared to projected climate change in many species. This pattern was only significant under assumptions of unlimited dispersal, however, where considerable climate-driven habitat gains offset some concurrent climate-driven habitat losses. Additionally, some of the habitat gained with projected climate change overlapped with projected land use. Most species showed potential northern habitat expansion and southern habitat contraction due to projected climate change, resulting in sharply contrasting patterns of impact between Central and South Coast Ecoregions. In the Central Coast, dispersal could play an important role moderating losses from both climate change and land use. In contrast, high geographic overlap in habitat losses driven by projected climate change and projected land use in the South Coast underscores the potential for compounding negative impacts of both drivers. Limiting habitat conversion may be a broadly beneficial strategy under climate change. We emphasize the importance of addressing both drivers in conservation and resource management planning.

Discrete Dynamics Model for the Speract-Activated Ca2+ Signaling Network Relevant to Sperm Motility

PubMed Central

Espinal, Jesús; Aldana, Maximino; Guerrero, Adán; Wood, Christopher

2011-01-01

Understanding how spermatozoa approach the egg is a central biological issue. Recently a considerable amount of experimental evidence has accumulated on the relation between oscillations in intracellular calcium ion concentration ([Ca]) in the sea urchin sperm flagellum, triggered by peptides secreted from the egg, and sperm motility. Determination of the structure and dynamics of the signaling pathway leading to these oscillations is a fundamental problem. However, a biochemically based formulation for the comprehension of the molecular mechanisms operating in the axoneme as a response to external stimulus is still lacking. Based on experiments on the S. purpuratus sea urchin spermatozoa, we propose a signaling network model where nodes are discrete variables corresponding to the pathway elements and the signal transmission takes place at discrete time intervals according to logical rules. The validity of this model is corroborated by reproducing previous empirically determined signaling features. Prompted by the model predictions we performed experiments which identified novel characteristics of the signaling pathway. We uncovered the role of a high voltage-activated channel as a regulator of the delay in the onset of fluctuations after activation of the signaling cascade. This delay time has recently been shown to be an important regulatory factor for sea urchin sperm reorientation. Another finding is the participation of a voltage-dependent calcium-activated channel in the determination of the period of the fluctuations. Furthermore, by analyzing the spread of network perturbations we find that it operates in a dynamically critical regime. Our work demonstrates that a coarse-grained approach to the dynamics of the signaling pathway is capable of revealing regulatory sperm navigation elements and provides insight, in terms of criticality, on the concurrence of the high robustness and adaptability that the reproduction processes are predicted to have developed throughout evolution. PMID:21857937

Initial care and outcome of glioblastoma multiforme patients in 2 diverse health care scenarios in Brazil: does public versus private health care matter?.

PubMed

Loureiro, Luiz Victor Maia; Pontes, Lucíola de Barros; Callegaro-Filho, Donato; Koch, Ludmila de Oliveira; Weltman, Eduardo; Victor, Elivane da Silva; Santos, Adrialdo José; Borges, Lia Raquel Rodrigues; Segreto, Roberto Araújo; Malheiros, Suzana Maria Fleury

2014-07-01

The aim of this study was to describe the epidemiological and survival features of patients with glioblastoma multiforme treated in 2 health care scenarios--public and private--in Brazil. We retrospectively analyzed clinical, treatment, and outcome characteristics of glioblastoma multiforme patients from 2003 to 2011 at 2 institutions. The median age of the 171 patients (117 public and 54 private) was 59.3 years (range, 18-84). The median survival for patients treated in private institutions was 17.4 months (95% confidence interval, 11.1-23.7) compared with 7.1 months (95% confidence interval, 3.8-10.4) for patients treated in public institutions (P < .001). The time from the first symptom to surgery was longer in the public setting (median of 64 days for the public hospital and 31 days for the private institution; P = .003). The patients at the private hospital received radiotherapy concurrent with chemotherapy in 59.3% of cases; at the public hospital, only 21.4% (P < .001). Despite these differences, the institution of treatment was not found to be an independent predictor of outcome (hazard ratio, 1.675; 95% confidence interval, 0.951-2.949; P = .074). The Karnofsky performance status and any additional treatment after surgery were predictors of survival. A hazard ratio of 0.010 (95% confidence interval, 0.003-0.033; P < .001) was observed for gross total tumor resection followed by radiotherapy concurrent with chemotherapy. Despite obvious disparities between the hospitals, the medical assistance scenario was not an independent predictor of survival. However, survival was directly influenced by additional treatment after surgery. Therefore, increasing access to resources in developing countries like Brazil is critical.

Inhibitory effect of ezetimibe can be prevented by an administration interval of 4 h between α-tocopherol and ezetimibe.

PubMed

Nashimoto, Shunsuke; Sato, Yuki; Takekuma, Yoh; Sugawara, Mitsuru

2017-05-01

Tocopherol is used not only as an ethical drug but also as a supplement. In 2008, it was reported that α-tocopherol is partly transported via an intestinal cholesterol transporter, Niemann-Pick C1-Like 1 (NPC1L1). Ezetimibe, a selective inhibitor of NPC1L1, is administered for a long time to inhibit cholesterol absorption and there is a possibility that the absorption of α-tocopherol is also inhibited by ezetimibe. This study investigated the influence of ezetimibe on the absorption of α-tocopherol with single administration and long-term administration. An approach to avoid its undesirable consequence was also examined. α-Tocopherol (10 mg/kg) and ezetimibe (0.1 mg/kg) were administered to rats, and the plasma concentration profiles of α-tocopherol and tissue concentrations were investigated. The plasma concentration of α-tocopherol was decreased by the combination use of ezetimibe in the case of concurrent single administration. On the other hand, inhibition of the absorption of α-tocopherol was prevented by an administration interval of 4 h. In a group of rats administered for 2 months with a 4 h interval, not only the plasma concentration but also the liver concentration was increased compared with those in a group with concurrent combination intake of α-tocopherol and ezetimibe. The absorption of α-tocopherol was inhibited by ezetimibe. The inhibitory effect of ezetimibe can be prevented by an administration interval of 4 h, although ezetimibe is a medicine of enterohepatic circulation. Attention should be paid to the use of ezetimibe and components of NPC1L1 substrates such as α-tocopherol. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Clinical study of concurrent chemoradiotherapy or radiotherapy alone for esophageal cancer patients with positive lymph node metastasis.

PubMed

Han, Jihua; Zhu, Weiguo; Yu, Changhua; Zhou, Xilei; Li, Tao; Zhang, Xiaoye

2012-01-01

Esophageal cancer patients with pathologic lymph node involvement generally have a poor prognosis. Many randomized controlled trials have not achieved consistent results similar to those of the RTOG8501 trial, and the long-term survival rate has not increased. The present study aimed to compare the efficacy and toxic side effects of concurrent chemoradiotherapy and radiotherapy alone to treat N1 esophageal carcinoma. A total of 130 N1 esophageal carcinoma patients were enrolled and randomly divided into two groups: concurrent chemoradiotherapy group (n = 65) and radiotherapy group (n = 65). Both groups received three-dimensional conformal radiotherapy with a total dose of 64-66 Gy. Meanwhile, to the concurrent chemoradiotherapy group, an additional chemotherapy protocol (nedaplatin, 20 mg/m²/d, 5-FU, 500 mg/m²/d for four days) was given from day 1, and such treatment was repeated until day 29. From day 21 after radiotherapy, two cycles of a consolidated chemotherapy protocol were given at an interval of 28 days. The survival rates at one, two, and three years were 72.3%, 55.3%, and 40% in the concurrent chemoradiotherapy group, respectively, and 75.3%, 38.5%, and 18.5% in the radiotheray group (P = 0.007), respectively. The survival rates of the patients in the concurrent chemoradiotherapy group who completed one to two cycles and three to four cycles at one, two, and three years were 70%, 53.3%, and 30%, and 74.2%, 57.1%, 48.6% (P = 0.128), respectively. Three-year distant metastasis rates were 10.7% in the concurrent chemoradiotherapy group and 16.9% in the radiotherapy group. Acute toxicity in the concurrent chemoradiotherapy group was higher than in the radiotherapy group. Late toxic side effects were similar in the two groups. Compared with radiotherapy alone, concurrent chemoradiotherapy in the treatment of esophageal carcinoma with local lymph node enlargement can improve the three-year survival rate. Moreover, completion of three to four cycles of chemotherapy may have better efficacy than one to two cycles.

Variability in the American Society of Anesthesiologists (ASA) Physical Status (PS) Classifcation Scale

DTIC Science & Technology

1999-10-01

instrument, and was deemed unsuitable because it was altered by several variables (patient condition, planned surgical procedure, experience and skill...index of anesthetic risk could be developed. Variables in addition to the patient physical status ( experience of the surgeon, anesthetist, and hospital...and other concurrent illnesses), but also by risk inherent to the specific surgery. Surgical risks include experience of the surgical team, the

Early 20th Century Arctic Warming Intensified by Pacific and Atlantic Multidecadal Variability

NASA Astrophysics Data System (ADS)

Tokinaga, H.; Xie, S. P.; Mukougawa, H.

2017-12-01

We investigate the influence of Pacific and Atlantic multidecadal variability on the Arctic temperature, with a particular focus on the early 20th century Arctic warming. Arctic surface air temperature increased rapidly over the early 20th century, at rates comparable to those of recent decades despite much weaker greenhouse gas forcing than at present. We find that the concurrent phase shift of Pacific and Atlantic multidecadal variability is the major driver for the early 20th century Arctic warming. Atmospheric model simulations reproduce the early Arctic warming when the interdecadal variability of sea surface temperature (SST) is properly prescribed. The early Arctic warming is associated with the cold-to-warm phase shifts of Atlantic and Pacific multidecadal variability modes, a SST pattern reminiscent of the positive phase of the Pacific decadal and Atlantic multidecadal oscillations. The extratropical North Atlantic and North Pacific SST warming strengthens surface westerly winds over northern Eurasia, intensifying the warming there. The equatorial Pacific warming deepens the Aleutian low, advecting warm air to the North American Arctic. Coupled ocean-atmosphere simulations support the constructive intensification of Arctic warming by a concurrent, cold-to-warm phase shift of the Pacific and Atlantic multidecadal variability. Our results aid attributing the historical Arctic warming and thereby constrain the amplified warming projected for this important region.

Thermal Entanglement in XXZ Heisenberg Model for Coupled Spin-Half and Spin-One Triangular Cell

NASA Astrophysics Data System (ADS)

Najarbashi, Ghader; Balazadeh, Leila; Tavana, Ali

2018-01-01

In this paper, we investigate the thermal entanglement of two-spin subsystems in an ensemble of coupled spin-half and spin-one triangular cells, (1/2, 1/2, 1/2), (1/2, 1, 1/2), (1, 1/2, 1) and (1, 1, 1) with the XXZ anisotropic Heisenberg model subjected to an external homogeneous magnetic field. We adopt the generalized concurrence as the measure of entanglement which is a good indicator of the thermal entanglement and the critical points in the mixed higher dimensional spin systems. We observe that in the near vicinity of the absolute zero, the concurrence measure is symmetric with respect to zero magnetic field and changes abruptly from a non-null to null value for a critical magnetic field that can be signature of a quantum phase transition at finite temperature. The analysis of concurrence versus temperature shows that there exists a critical temperature, that depends on the type of the interaction, i.e. ferromagnetic or antiferromagnetic, the anisotropy parameter and the strength of the magnetic field. Results show that the pairwise thermal entanglement depends on the third spin which affects the maximum value of the concurrence at absolute zero and at quantum critical points.

Beat-to-beat control of human optokinetic nystagmus slow phase durations

PubMed Central

Furman, Joseph M.

2016-01-01

This study provides the first clear evidence that the generation of optokinetic nystagmus fast phases (FPs) is a decision process that is influenced by performance of a concurrent disjunctive reaction time task (DRT). Ten subjects performed an auditory DRT during constant velocity optokinetic stimulation. Eye movements were measured in three dimensions with a magnetic search coil. Slow phase (SP) durations were defined as the interval between FPs. There were three main findings. Firstly, human optokinetic nystagmus SP durations are consistent with a model of a Gaussian basic interval generator (a type of biological clock), such that FPs can be triggered randomly at the end of a clock cycle (mean duration: 200–250 ms). Kolmogorov-Smirnov tests could not reject the modeled cumulative distribution for any data trials. Secondly, the FP need not be triggered at the end of a clock cycle, so that individual SP durations represent single or multiple clock cycles. Thirdly, the probability of generating a FP at the end of each interval generator cycle decreases significantly during performance of a DRT. These findings indicate that the alternation between SPs and FPs of optokinetic nystagmus is not purely reflexive. Rather, the triggering of the next FP is postponed more frequently if a recently presented DRT trial is pending action when the timing cycle expires. Hence, optokinetic nystagmus FPs show dual-task interference in a manner usually attributed to voluntary movements, including saccades. NEW & NOTEWORTHY This study provides the first clear evidence that the generation of optokinetic nystagmus (OKN) fast phases is a decision process that is influenced by performance of a concurrent disjunctive reaction time task (DRT). The slow phase (SP) durations are consistent with a Gaussian basic interval generator and multiple interval SP durations occur more frequently in the presence of the DRT. Hence, OKN shows dual-task interference in a manner observed in voluntary movements, such as saccades. PMID:27760815

Beat-to-beat control of human optokinetic nystagmus slow phase durations.

PubMed

Balaban, Carey D; Furman, Joseph M

2017-01-01

This study provides the first clear evidence that the generation of optokinetic nystagmus fast phases (FPs) is a decision process that is influenced by performance of a concurrent disjunctive reaction time task (DRT). Ten subjects performed an auditory DRT during constant velocity optokinetic stimulation. Eye movements were measured in three dimensions with a magnetic search coil. Slow phase (SP) durations were defined as the interval between FPs. There were three main findings. Firstly, human optokinetic nystagmus SP durations are consistent with a model of a Gaussian basic interval generator (a type of biological clock), such that FPs can be triggered randomly at the end of a clock cycle (mean duration: 200-250 ms). Kolmogorov-Smirnov tests could not reject the modeled cumulative distribution for any data trials. Secondly, the FP need not be triggered at the end of a clock cycle, so that individual SP durations represent single or multiple clock cycles. Thirdly, the probability of generating a FP at the end of each interval generator cycle decreases significantly during performance of a DRT. These findings indicate that the alternation between SPs and FPs of optokinetic nystagmus is not purely reflexive. Rather, the triggering of the next FP is postponed more frequently if a recently presented DRT trial is pending action when the timing cycle expires. Hence, optokinetic nystagmus FPs show dual-task interference in a manner usually attributed to voluntary movements, including saccades. This study provides the first clear evidence that the generation of optokinetic nystagmus (OKN) fast phases is a decision process that is influenced by performance of a concurrent disjunctive reaction time task (DRT). The slow phase (SP) durations are consistent with a Gaussian basic interval generator and multiple interval SP durations occur more frequently in the presence of the DRT. Hence, OKN shows dual-task interference in a manner observed in voluntary movements, such as saccades. Copyright © 2017 the American Physiological Society.

Concurrent sexual partnerships among married Zimbabweans – implications for HIV prevention

PubMed Central

Mugweni, Esther; Pearson, Stephen; Omar, Mayeh

2015-01-01

Background Concurrent sexual partnerships play a key role in sustaining the HIV epidemic in Zimbabwe. Married couples are at an increased risk of contracting HIV from sexual networks produced by concurrent sexual partnerships. Addressing these partnerships is an international HIV prevention priority. Methods Our qualitative study presents the socioeconomic factors that contribute to the occurrence of concurrent sexual partnerships among married people in Zimbabwe. We conducted 36 in-depth interviews and four focus group discussions with married men and women in Zimbabwe in 2008 to understand the organizations of concurrent sexual partnerships. Data were analyzed using framework analysis. Results Our study indicates that relationship dissatisfaction played a key role in the engagement of concurrent sexual partnerships. Depending on the source of the dissatisfaction, there were four possible types of concurrent sexual relationships that were formed: sex worker, casual partner, regular girlfriend or informal polygyny which was referred to as “small house”. These relationships had different levels of intimacy, which had a bearing on practicing safer sex. Participants described three characteristics of hegemonic masculinity that contributed to the sources of dissatisfaction leading to concurrent sexual activity. Similarly, various aspects of emphasized femininity were described as creating opportunities for the occurrence of concurrent sexual relationships. Economic status was also listed as a factor that contributed to the occurrence of concurrent sexual partnerships. Conclusion Marital dissatisfaction was indicated as a contributing factor to the occurrence of concurrent sexual relationships. There were several reports of satisfying marital relationships in which affairs did not occur. Lessons from these marriages can be made part of future HIV prevention interventions targeted at preventing concurrent sexual partnerships by married couples. PMID:26491372

Association of Fatigue With Sarcopenia and its Elements: A Secondary Analysis of SABE-Bogotá

PubMed Central

Patino-Hernandez, Daniela; David-Pardo, David Gabriel; Borda, Miguel Germán; Pérez-Zepeda, Mario Ulises; Cano-Gutiérrez, Carlos

2017-01-01

Objective: Sarcopenia, fatigue, and depression are associated with higher mortality rates and adverse outcomes in the aging population. Understanding the association among clinical variables, mainly symptoms, is important for screening and appropriately managing these conditions. The aim of this article is to evaluate the association among sarcopenia and its elements with depression and fatigue. Method: We used cross-sectional data from 2012 SABE (Salud, Bienestar y Envejecimiento)-Bogotá study, which included 2,000 participants of ages ≥60 years. Sarcopenia and its elements were taken as the dependent variable, while fatigue and depression were the main independent variables. We tested the association among these through multiple logistic regression models, which were fitted for each dependent variable and adjusted for confounding variables. Results: Our findings showed that gait speed was associated with fatigue (adjusted odds ratio [OR] = 1.41, 95% confidence interval [CI] = [1.05, 1.90], p = .02) as well as abnormal handgrip strength (adjusted OR = 1.40, 95% CI = [1.02, 1.93], p = .04). No other associations were significant. Conclusion: While sarcopenia and fatigue are not associated, two of the sarcopenia-defining variables are associated with fatigue; this suggests that lack of sarcopenia does not exclude undesirable outcomes related to fatigue in aging adults. Also, the lack of association between sarcopenia-defining elements and depression demonstrates that depression and fatigue are different concepts. PMID:28474000

Unusual Necrotizing Encephalitis in Raccoons and Skunks Concurrently Infected With Canine Distemper Virus and Sarcocystis sp.

PubMed

Kubiski, S V; Sisó, S; Church, M E; Cartoceti, A N; Barr, B; Pesavento, P A

2016-05-01

Canine distemper virus commonly infects free-ranging, terrestrial mesopredators throughout the United States. Due to the immunosuppressive effects of the virus, concurrent opportunistic infections are also common. Among these, secondary systemic protozoal infections have been described in a number of species. We report an unusual presentation of necrotizing encephalitis associated withSarcocystissp in four raccoons and one skunk concurrently infected with canine distemper virus. Lesions were characterized by variably sized necrotizing cavitations composed of abundant mineral admixed with inflammatory cells and protozoa.Sarcocystissp was confirmed via immunohistochemistry using a monoclonal antibody toSarcocystis neurona The pathologic changes are similar to lesions in human AIDS patients infected withToxoplasma gondii. © The Author(s) 2015.

The psychometric properties of Observer OPTION(5), an observer measure of shared decision making.

PubMed

Barr, Paul J; O'Malley, Alistair James; Tsulukidze, Maka; Gionfriddo, Michael R; Montori, Victor; Elwyn, Glyn

2015-08-01

Observer OPTION(5) was designed as a more efficient version of OPTION(12), the most commonly used measure of shared decision making (SDM). The current paper assesses the psychometric properties of OPTION(5). Two raters used OPTION(5) to rate recordings of clinical encounters from two previous patient decision aid (PDA) trials (n=201; n=110). A subsample was re-rated two weeks later. We assessed discriminative validity, inter-rater reliability, intra-rater reliability, and concurrent validity. OPTION(5) demonstrated discriminative validity, with increases in SDM between usual care and PDA arms. OPTION(5) also demonstrated concurrent validity with OPTION(12), r=0.61 (95%CI 0.54, 0.68) and intra-rater reliability, r=0.93 (0.83, 0.97). The mean difference in rater score was 8.89 (95% Credibility Interval, 7.5, 10.3), with intraclass correlation (ICC) of 0.67 (95% Credibility Interval, 0.51, 0.91) for the accuracy of rater scores and 0.70 (95% Credibility Interval, 0.56, 0.94) for the consistency of rater scores across encounters, indicating good inter-rater reliability. Raters reported lower cognitive burden when using OPTION(5) compared to OPTION(12). OPTION(5) is a brief, theoretically grounded observer measure of SDM with promising psychometric properties in this sample and low burden on raters. OPTION(5) has potential to provide reliable, valid assessment of SDM in clinical encounters. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Determinants of birth intervals in Kerala: an application of Cox's hazard model.

PubMed

Nair, S N

1996-01-01

"The present study is an attempt to delineate the differences in the patterns and determinants of birth intervals which appear highly relevant in a transitional population such as Kerala [India]. In this country two comparable surveys, with a period difference of 20 years, were conducted. The study tries to estimate the effects of socio-economic, demographic and proximate variables using Cox's proportional hazard model. For the former data-set, socio-economic variables have [a] significant effect on birth intervals, while for the latter data proximate variables are the significant determinants of birth intervals." (SUMMARY IN ITA AND FRE) excerpt

Concurrent Associations between Physical Activity, Screen Time, and Sleep Duration with Childhood Obesity.

PubMed

Laurson, Kelly R; Lee, Joey A; Gentile, Douglas A; Walsh, David A; Eisenmann, Joey C

2014-01-01

Aim. To examine the simultaneous influence of physical activity, screen time, and sleep duration recommendations on the odds of childhood obesity (including overweight). Methods. Physical activity was assessed via pedometer and screen time, and sleep duration were assessed via survey in a cross sectional sample of 674 children (aged 7-12 years) from two Midwestern communities in the fall of 2005. Participants were cross tabulated into four groups depending on how many recommendations were being met (0, 1, 2, or all 3). Linear and logistic regression were used to examine the influence of physical activity, screen time and sleep duration on obesity and interactions among the three variables. Results. Children achieving all three recommendations simultaneously (9.2% of total sample) were the least likely to be obese. Approximately 16% of boys and 9% of girls achieving all recommendations were overweight or obese compared to 53% of boys and 42.5% of girls not achieving any. Conclusions. The odds of obesity increased in a graded manner for each recommendation which was not met. Meeting all three recommendations appears to have a protective effect against obesity. Continued efforts are warranted to promote healthy lifestyle behaviors that include meeting physical activity, screen time, and sleep duration recommendations concurrently.

Concurrent Associations between Physical Activity, Screen Time, and Sleep Duration with Childhood Obesity

PubMed Central

Laurson, Kelly R.; Lee, Joey A.; Gentile, Douglas A.; Walsh, David A.; Eisenmann, Joey C.

2014-01-01

Aim. To examine the simultaneous influence of physical activity, screen time, and sleep duration recommendations on the odds of childhood obesity (including overweight). Methods. Physical activity was assessed via pedometer and screen time, and sleep duration were assessed via survey in a cross sectional sample of 674 children (aged 7–12 years) from two Midwestern communities in the fall of 2005. Participants were cross tabulated into four groups depending on how many recommendations were being met (0, 1, 2, or all 3). Linear and logistic regression were used to examine the influence of physical activity, screen time and sleep duration on obesity and interactions among the three variables. Results. Children achieving all three recommendations simultaneously (9.2% of total sample) were the least likely to be obese. Approximately 16% of boys and 9% of girls achieving all recommendations were overweight or obese compared to 53% of boys and 42.5% of girls not achieving any. Conclusions. The odds of obesity increased in a graded manner for each recommendation which was not met. Meeting all three recommendations appears to have a protective effect against obesity. Continued efforts are warranted to promote healthy lifestyle behaviors that include meeting physical activity, screen time, and sleep duration recommendations concurrently. PMID:24734210

Influence of Pacing by Periodic Auditory Stimuli on Movement Continuation: Comparison with Self-regulated Periodic Movement

PubMed Central

Ito, Masanori; Kado, Naoki; Suzuki, Toshiaki; Ando, Hiroshi

2013-01-01

[Purpose] The purpose of this study was to investigate the influence of external pacing with periodic auditory stimuli on the control of periodic movement. [Subjects and Methods] Eighteen healthy subjects performed self-paced, synchronization-continuation, and syncopation-continuation tapping. Inter-onset intervals were 1,000, 2,000 and 5,000 ms. The variability of inter-tap intervals was compared between the different pacing conditions and between self-paced tapping and each continuation phase. [Results] There were no significant differences in the mean and standard deviation of the inter-tap interval between pacing conditions. For the 1,000 and 5,000 ms tasks, there were significant differences in the mean inter-tap interval following auditory pacing compared with self-pacing. For the 2,000 ms syncopation condition and 5,000 ms task, there were significant differences from self-pacing in the standard deviation of the inter-tap interval following auditory pacing. [Conclusion] These results suggest that the accuracy of periodic movement with intervals of 1,000 and 5,000 ms can be improved by the use of auditory pacing. However, the consistency of periodic movement is mainly dependent on the inherent skill of the individual; thus, improvement of consistency based on pacing is unlikely. PMID:24259932

Retest reliability of force-time variables of neck muscles under isometric conditions.

PubMed

Almosnino, Sivan; Pelland, Lucie; Stevenson, Joan M

2010-01-01

Proper conditioning of the neck muscles may play a role in reducing the risk of neck injury and, possibly, concussions in contact sports. However, the ability to reliably measure the force-time-based variables that might be relevant for this purpose has not been addressed. To assess the between-days reliability of discrete force-time-based variables of neck muscles during maximal voluntary isometric contractions in 5 directions. Cohort study. University research center. Twenty-six highly physically active men (age  =  21.6 ± 2.1 years, height  =  1.85 ± 0.09 m, mass  =  81.6 ± 9.9 kg, head circumference  =  0.58 ± 0.01 m, neck circumference  =  0.39 ± 0.02 m). We used a custom-built testing apparatus to measure maximal voluntary isometric contractions of the neck muscles in 5 directions (extension, flexion, protraction, left lateral bending, and right lateral bending) on 2 separate occasions separated by 7 to 8 days. Variables measured were peak force (PF), rate of force development (RFD), and time to 50% of PF (T(50)PF). Reliability indices calculated for each variable comprised the difference in scores between the testing sessions, with corresponding 95% confidence intervals, the coefficient of variation of the typical error of measurement (CV(TE)), and intraclass correlation coefficients (ICC [3,3]). No evidence of systematic bias was detected for the dependent measures across any movement direction; retest differences in measurements were between 1.8% and 2.7%, with corresponding 95% confidence interval ranges of less than 10% and overlapping zero. The CV(TE) was lowest for PF (range, 2.4%-6.3%) across all testing directions, followed by RFD (range, 4.8%-9.0%) and T(50)PF (range, 7.1%-9.3%). The ICC score range for all dependent measures was 0.90 to 0.99. Discrete variables representative of the force-generating capacity of neck muscles under isometric conditions can be measured with an acceptable degree of reliability. This finding has possible applications for investigating the role of neck muscle strength-training programs in reducing the risk of injuries in sport settings.

An Alternative to the Stay/Switch Equation Assessed When Using a Changeover-Delay

PubMed Central

MacDonall, James S.

2015-01-01

An alternative to the generalized matching equation for understanding concurrent performances is the stay/switch model. For the stay/switch model, the important events are the contingencies and behaviors at each alternative. The current experiment compares the descriptions by two stay/switch equations, the original, empirically derived stay/switch equation and a more theoretically derived equation based on ratios of stay to switch responses matching ratios of stay to switch reinforcers. The present experiment compared descriptions by the original stay/switch equation when using and not using a changeover delay. It also compared descriptions by the more theoretical equation with and without a changeover delay. Finally, it compared descriptions of the concurrent performances by these two equations. Rats were trained in 15 conditions on identical concurrent random-interval schedules in each component of a multiple schedule. A COD operated in only one component. There were no consistent differences in the variance accounted for by each equation of concurrent performances whether or not a COD was used. The simpler equation found greater sensitivity to stay than to switch reinforcers. It also found a COD eliminated the influence of switch reinforcers. Because estimates of parameters were more meaningful when using the more theoretical stay/switch equation it is preferred. PMID:26299548

An alternative to the stay/switch equation assessed when using a changeover-delay.

PubMed

MacDonall, James S

2015-11-01

An alternative to the generalized matching equation for understanding concurrent performances is the stay/switch model. For the stay/switch model, the important events are the contingencies and behaviors at each alternative. The current experiment compares the descriptions by two stay/switch equations, the original, empirically derived stay/switch equation and a more theoretically derived equation based on ratios of stay to switch responses matching ratios of stay to switch reinforcers. The present experiment compared descriptions by the original stay/switch equation when using and not using a changeover delay. It also compared descriptions by the more theoretical equation with and without a changeover delay. Finally, it compared descriptions of the concurrent performances by these two equations. Rats were trained in 15 conditions on identical concurrent random-interval schedules in each component of a multiple schedule. A COD operated in only one component. There were no consistent differences in the variance accounted for by each equation of concurrent performances whether or not a COD was used. The simpler equation found greater sensitivity to stay than to switch reinforcers. It also found a COD eliminated the influence of switch reinforcers. Because estimates of parameters were more meaningful when using the more theoretical stay/switch equation it is preferred. Copyright © 2015 Elsevier B.V. All rights reserved.

Bi-Level Integrated System Synthesis (BLISS) for Concurrent and Distributed Processing

NASA Technical Reports Server (NTRS)

Sobieszczanski-Sobieski, Jaroslaw; Altus, Troy D.; Phillips, Matthew; Sandusky, Robert

2002-01-01

The paper introduces a new version of the Bi-Level Integrated System Synthesis (BLISS) methods intended for optimization of engineering systems conducted by distributed specialty groups working concurrently and using a multiprocessor computing environment. The method decomposes the overall optimization task into subtasks associated with disciplines or subsystems where the local design variables are numerous and a single, system-level optimization whose design variables are relatively few. The subtasks are fully autonomous as to their inner operations and decision making. Their purpose is to eliminate the local design variables and generate a wide spectrum of feasible designs whose behavior is represented by Response Surfaces to be accessed by a system-level optimization. It is shown that, if the problem is convex, the solution of the decomposed problem is the same as that obtained without decomposition. A simplified example of an aircraft design shows the method working as intended. The paper includes a discussion of the method merits and demerits and recommendations for further research.

Hydropower plans in eastern and southern Africa increase risk of concurrent climate-related electricity supply disruption

NASA Astrophysics Data System (ADS)

Conway, Declan; Dalin, Carole; Landman, Willem A.; Osborn, Timothy J.

2017-12-01

Hydropower comprises a significant and rapidly expanding proportion of electricity production in eastern and southern Africa. In both regions, hydropower is exposed to high levels of climate variability and regional climate linkages are strong, yet an understanding of spatial interdependences is lacking. Here we consider river basin configuration and define regions of coherent rainfall variability using cluster analysis to illustrate exposure to the risk of hydropower supply disruption of current (2015) and planned (2030) hydropower sites. Assuming completion of the dams planned, hydropower will become increasingly concentrated in the Nile (from 62% to 82% of total regional capacity) and Zambezi (from 73% to 85%) basins. By 2030, 70% and 59% of total hydropower capacity will be located in one cluster of rainfall variability in eastern and southern Africa, respectively, increasing the risk of concurrent climate-related electricity supply disruption in each region. Linking of nascent regional electricity sharing mechanisms could mitigate intraregional risk, although these mechanisms face considerable political and infrastructural challenges.

Impact of early and concurrent stunting on cognition.

PubMed

Crookston, Benjamin T; Dearden, Kirk A; Alder, Stephen C; Porucznik, Christina A; Stanford, Joseph B; Merrill, Ray M; Dickerson, Ty T; Penny, Mary E

2011-10-01

Undernutrition is associated with poor cognitive development, late entry into school, decreased years of schooling, reduced productivity and smaller adult stature. We use longitudinal data from 1674 Peruvian children participating in the Young Lives study to assess the relative impact of early stunting (stunted at 6-18 months of age) and concurrent stunting (stunted at 4.5-6 years of age) on cognitive ability. Anthropometric data were longitudinally collected for children at 6-18 months of age and 4.5-6 years of age at which time verbal and quantitative ability were also assessed. We estimate that an increase in concurrent height-for-age z-scores (HAZ) by one standard deviation was associated with an increase in a child's score on the Peabody Picture Vocabulary Test (PPVT) by 2.35 points [confidence interval (CI): 1.55-3.15] and a 0.16 point increase on the cognitive development assessment (CDA) (CI: 0.05-0.27). Furthermore, we report that the estimate for concurrent HAZ and PPVT is significantly higher than the estimate for early stunting and PPVT. We found no significant difference between early and concurrent estimates for HAZ and CDA. Children from older mothers, children whose mothers had higher education levels, children living in urban areas, children who attended pre-school, children with fewer siblings and children from wealthier backgrounds scored higher on both assessments. Cognitive skills of children entering school were associated with early stunting but the strongest association was found with concurrent stunting suggesting that interventions preventing linear growth faltering should not only focus on the under 2s but include children up to 5 years of age. © 2010 Blackwell Publishing Ltd.

Variable-Interval Sequenced-Action Camera (VINSAC). Dissemination Document No. 1.

ERIC Educational Resources Information Center

Ward, Ted

The 16 millimeter (mm) Variable-Interval Sequenced-Action Camera (VINSAC) is designed for inexpensive photographic recording of effective teacher instruction and use of instructional materials for teacher education and research purposes. The camera photographs single frames at preselected time intervals (.5 second to 20 seconds) which are…

A general strategy for performing temperature-programming in high performance liquid chromatography--further improvements in the accuracy of retention time predictions of segmented temperature gradients.

PubMed

Wiese, Steffen; Teutenberg, Thorsten; Schmidt, Torsten C

2012-01-27

In the present work it is shown that the linear elution strength (LES) model which was adapted from temperature-programming gas chromatography (GC) can also be employed for systematic method development in high-temperature liquid chromatography (HT-HPLC). The ability to predict isothermal retention times based on temperature-gradient as well as isothermal input data was investigated. For a small temperature interval of ΔT=40°C, both approaches result in very similar predictions. Average relative errors of predicted retention times of 2.7% and 1.9% were observed for simulations based on isothermal and temperature-gradient measurements, respectively. Concurrently, it was investigated whether the accuracy of retention time predictions of segmented temperature gradients can be further improved by temperature dependent calculation of the parameter S(T) of the LES relationship. It was found that the accuracy of retention time predictions of multi-step temperature gradients can be improved to around 1.5%, if S(T) was also calculated temperature dependent. The adjusted experimental design making use of four temperature-gradient measurements was applied for systematic method development of selected food additives by high-temperature liquid chromatography. Method development was performed within a temperature interval from 40°C to 180°C using water as mobile phase. Two separation methods were established where selected food additives were baseline separated. In addition, a good agreement between simulation and experiment was observed, because an average relative error of predicted retention times of complex segmented temperature gradients less than 5% was observed. Finally, a schedule of recommendations to assist the practitioner during systematic method development in high-temperature liquid chromatography was established. Copyright © 2011 Elsevier B.V. All rights reserved.

Kinematic variability, fractal dynamics and local dynamic stability of treadmill walking

PubMed Central

2011-01-01

Background Motorized treadmills are widely used in research or in clinical therapy. Small kinematics, kinetics and energetics changes induced by Treadmill Walking (TW) as compared to Overground Walking (OW) have been reported in literature. The purpose of the present study was to characterize the differences between OW and TW in terms of stride-to-stride variability. Classical (Standard Deviation, SD) and non-linear (fractal dynamics, local dynamic stability) methods were used. In addition, the correlations between the different variability indexes were analyzed. Methods Twenty healthy subjects performed 10 min TW and OW in a random sequence. A triaxial accelerometer recorded trunk accelerations. Kinematic variability was computed as the average SD (MeanSD) of acceleration patterns among standardized strides. Fractal dynamics (scaling exponent α) was assessed by Detrended Fluctuation Analysis (DFA) of stride intervals. Short-term and long-term dynamic stability were estimated by computing the maximal Lyapunov exponents of acceleration signals. Results TW did not modify kinematic gait variability as compared to OW (multivariate T2, p = 0.87). Conversely, TW significantly modified fractal dynamics (t-test, p = 0.01), and both short and long term local dynamic stability (T2 p = 0.0002). No relationship was observed between variability indexes with the exception of significant negative correlation between MeanSD and dynamic stability in TW (3 × 6 canonical correlation, r = 0.94). Conclusions Treadmill induced a less correlated pattern in the stride intervals and increased gait stability, but did not modify kinematic variability in healthy subjects. This could be due to changes in perceptual information induced by treadmill walking that would affect locomotor control of the gait and hence specifically alter non-linear dependencies among consecutive strides. Consequently, the type of walking (i.e. treadmill or overground) is important to consider in each protocol design. PMID:21345241

An Investigation on Attributes of Ambient Temperature and Diurnal Temperature Range on Mortality in Five East-Asian Countries.

PubMed

Lee, Whan-Hee; Lim, Youn-Hee; Dang, Tran Ngoc; Seposo, Xerxes; Honda, Yasushi; Guo, Yue-Liang Leon; Jang, Hye-Min; Kim, Ho

2017-08-31

Interest in the health effects of extremely low/high ambient temperature and the diurnal temperature range (DTR) on mortality as representative indices of temperature variability is growing. Although numerous studies have reported on these indices independently, few studies have provided the attributes of ambient temperature and DTR related to mortality, concurrently. In this study, we aimed to investigate and compare the mortality risk attributable to ambient temperature and DTR. The study included data of 63 cities in five East-Asian countries/regions during various periods between 1972 and 2013. The attributable risk of non-accidental death to ambient temperature was 9.36% (95% confidence interval [CI]: 8.98-9.69%) and to DTR was 0.59% (95% CI: 0.53-0.65%). The attributable cardiovascular mortality risks to ambient temperature (15.63%) and DTR (0.75%) are higher than the risks to non-accidental/respiratory-related mortality. We verified that ambient temperature plays a larger role in temperature-associated mortality, and cardiovascular mortality is susceptible to ambient temperature and DTR.

Rapid localized spread and immunologic containment define Herpes simplex virus-2 reactivation in the human genital tract.

PubMed

Schiffer, Joshua T; Swan, David; Al Sallaq, Ramzi; Magaret, Amalia; Johnston, Christine; Mark, Karen E; Selke, Stacy; Ocbamichael, Negusse; Kuntz, Steve; Zhu, Jia; Robinson, Barry; Huang, Meei-Li; Jerome, Keith R; Wald, Anna; Corey, Lawrence

2013-04-16

Herpes simplex virus-2 (HSV-2) is shed episodically, leading to occasional genital ulcers and efficient transmission. The biology explaining highly variable shedding patterns, in an infected person over time, is poorly understood. We sampled the genital tract for HSV DNA at several time intervals and concurrently at multiple sites, and derived a spatial mathematical model to characterize dynamics of HSV-2 reactivation. The model reproduced heterogeneity in shedding episode duration and viral production, and predicted rapid early viral expansion, rapid late decay, and wide spatial dispersion of HSV replication during episodes. In simulations, HSV-2 spread locally within single ulcers to thousands of epithelial cells in <12 hr, but host immune responses eliminated infected cells in <24 hr; secondary ulcers formed following spatial propagation of cell-free HSV-2, allowing for episode prolongation. We conclude that HSV-2 infection is characterized by extremely rapid virological growth and containment at multiple contemporaneous sites within genital epithelium. DOI:http://dx.doi.org/10.7554/eLife.00288.001.

Rapid localized spread and immunologic containment define Herpes simplex virus-2 reactivation in the human genital tract

PubMed Central

Schiffer, Joshua T; Swan, David; Al Sallaq, Ramzi; Magaret, Amalia; Johnston, Christine; Mark, Karen E; Selke, Stacy; Ocbamichael, Negusse; Kuntz, Steve; Zhu, Jia; Robinson, Barry; Huang, Meei-Li; Jerome, Keith R; Wald, Anna; Corey, Lawrence

2013-01-01

Herpes simplex virus-2 (HSV-2) is shed episodically, leading to occasional genital ulcers and efficient transmission. The biology explaining highly variable shedding patterns, in an infected person over time, is poorly understood. We sampled the genital tract for HSV DNA at several time intervals and concurrently at multiple sites, and derived a spatial mathematical model to characterize dynamics of HSV-2 reactivation. The model reproduced heterogeneity in shedding episode duration and viral production, and predicted rapid early viral expansion, rapid late decay, and wide spatial dispersion of HSV replication during episodes. In simulations, HSV-2 spread locally within single ulcers to thousands of epithelial cells in <12 hr, but host immune responses eliminated infected cells in <24 hr; secondary ulcers formed following spatial propagation of cell-free HSV-2, allowing for episode prolongation. We conclude that HSV-2 infection is characterized by extremely rapid virological growth and containment at multiple contemporaneous sites within genital epithelium. DOI: http://dx.doi.org/10.7554/eLife.00288.001 PMID:23606943

Synopsis of timing measurement techniques used in telecommunications

NASA Technical Reports Server (NTRS)

Zampetti, George

1993-01-01

Historically, Maximum Time Interval Error (MTIE) and Maximum Relative Time Interval Error (MRTIE) have been the main measurement techniques used to characterize timing performance in telecommunications networks. Recently, a new measurement technique, Time Variance (TVAR) has gained acceptance in the North American (ANSI) standards body. TVAR was developed in concurrence with NIST to address certain inadequacies in the MTIE approach. The advantages and disadvantages of each of these approaches are described. Real measurement examples are presented to illustrate the critical issues in actual telecommunication applications. Finally, a new MTIE measurement is proposed (ZTIE) that complements TVAR. Together, TVAR and ZTIE provide a very good characterization of network timing.

Investigation of within- and between-herd variability of bovine leukaemia virus bulk tank milk antibody levels over different sampling intervals in the Canadian Maritimes.

PubMed

John, Emily E; Nekouei, Omid; McClure, J T; Cameron, Marguerite; Keefe, Greg; Stryhn, Henrik

2018-06-01

Bulk tank milk (BTM) samples are used to determine the infection status and estimate dairy herd prevalence for bovine leukaemia virus (BLV) using an antibody ELISA assay. BLV ELISA variability between samples from the same herd or from different herds has not been investigated over long time periods. The main objective of this study was to determine the within-herd and between-herd variability of a BTM BLV ELISA assay over 1-month, 3-month, and 3-year sampling intervals. All of the Canadian Maritime region dairy herds (n = 523) that were active in 2013 and 2016 were included (83.9% and 86.9% of total herds in 2013 and 2016, respectively). BLV antibody levels were measured in three BTM samples collected at 1-month intervals in early 2013 as well as two BTM samples collected over a 3-month interval in early 2016. Random-effects models, with fixed effects for sample replicate and province and random effects for herd, were used to estimate the variability between BTM samples from the same herd and between herds for 1-month, 3-month, and 3-year sampling intervals. The majority of variability of BTM BLV ELISA results was seen between herds (1-month, 6.792 ± 0.533; 3-month, 7.806 ± 0.652; 3-year, 6.222 ± 0.528). Unexplained variance between samples from the same herd, on square-root scale, was greatest for the 3-year (0.976 ± 0.104), followed by the 1-month (0.611 ± 0.035) then the 3-month (0.557 ± 0.071) intervals. Variability of BTM antibody levels within the same herd was present but was much smaller than the variability between herds, and was greatest for the 3-year sampling interval. The 3-month sampling interval resulted in the least variability and is appropriate to use for estimating the baseline level of within-herd prevalence for BLV control programs. Knowledge of the baseline variability and within-herd prevalence can help to determine effectiveness of control programs when BTM sampling is repeated at longer intervals. Copyright © 2018 Elsevier B.V. All rights reserved.

Effectiveness of combination packages for HIV-1 prevention in sub-Saharan Africa depends on partnership network structure: a mathematical modelling study.

PubMed

Jenness, Samuel M; Goodreau, Steven M; Morris, Martina; Cassels, Susan

2016-12-01

Combination packages for HIV prevention can leverage the effectiveness of biomedical and behavioural elements to lower disease incidence with realistic targets for individual and population risk reduction. We investigated how sexual network structures can maximise the effectiveness of a package targeting sexually active adults in sub-Saharan Africa (SSA) with intervention components for medical male circumcision (MMC) and sexual partnership concurrency (having >1 ongoing partner). Network-based mathematical models of HIV type 1 (HIV-1) transmission dynamics among heterosexual couples were used to explore how changes to MMC alone and in combination with changes to concurrency impacted endemic HIV-1 prevalence and incidence. Starting from a base model parameterised from empirical data from West Africa, we simulated the prevalence of circumcision from 10% to 90% and concurrency was modelled at four discrete levels corresponding to values observed across SSA. MMC and concurrency could contribute to the empirical variation in HIV-1 disease prevalence across SSA. Small reductions in concurrency resulted in large declines in HIV-1 prevalence. Scaling up circumcision in low-concurrency settings yields a greater relative benefit, but the absolute number of infections averted depends on both the circumcision coverage and baseline incidence. Epidemic extinction with this package will require substantial scale-up of MMC in low-concurrency settings. Dynamic sexual network structure should be considered in the design and targeting of MMC within combination HIV-1 prevention packages. Realistic levels of coverage for these packages within southern Africa could lead to a reduction of incidence to the low levels observed in western Africa, and possibly, epidemic extinction. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Factor Validation of the Addiction Severity Index Scale Structure in Persons With Concurrent Disorders

ERIC Educational Resources Information Center

Currie, Shawn R.; el-Guebaly, Nady; Coulson, Ronaye; Hodgins, David; Mansley, Chrystal

2004-01-01

Confirmatory factor analysis was used to test the scale structure of the Addiction Severity Index (ASI) in a sample of 1,802 substance abusers (43% alcohol dependent) with a concurrent psychiatric disorder (46% with mood disorders). The fit of the original composite score model based on the work of P. L. McGahan, J. A. Griffith, R. Parente, & A.…

Dysthymic Disorder and Double Depression: Prediction of 10-Year Course Trajectories and Outcomes

PubMed Central

Klein, Daniel N.; Shankman, Stewart A.; Rose, Suzanne

2008-01-01

We sought to identify baseline predictors of 10-year course trajectories and outcomes in patients with dysthymic disorder and double depression. Eighty-seven outpatients with early-onset (< 21 years) dysthymic disorder, with or without superimposed major depression, were assessed five times at 30-month intervals for 10 years. Baseline evaluations included semi-structured diagnostic interviews for Axis I and II psychopathology and childhood adversity. Direct interview and family history data were collected on first-degree relatives. Follow-up assessments included the Longitudinal Follow-up Evaluation and Hamilton Depression Rating Scale. Using mixed effects growth curve models, univariate predictors of depression severity and functional impairment at 10-year outcome included older age, less education, concurrent anxiety disorder, greater familial loading for chronic depression, a history of a poorer maternal relationship in childhood, and a history of childhood sexual abuse. In addition, longer duration of dysthymic disorder also predicted greater impairment 10 years later. Predictors of a poorer trajectory of depressive symptoms over time included ethnicity and personality disorders; predictors of a poorer trajectory of social functioning included familial loading of chronic depression and quality of the childhood maternal relationship. Thus, demographic, clinical, family history, and early adversity variables all contribute to predicting the long term trajectory and outcome of DD. These variables should be routinely assessed in clinical evaluations and can provide clinicians with valuable prognostic information. PMID:17466334

Dysthymic disorder and double depression: prediction of 10-year course trajectories and outcomes.

PubMed

Klein, Daniel N; Shankman, Stewart A; Rose, Suzanne

2008-04-01

We sought to identify baseline predictors of 10-year course trajectories and outcomes in patients with dysthymic disorder and double depression. Eighty-seven outpatients with early-onset (<21 years) dysthymic disorder, with or without superimposed major depression, were assessed five times at 30-month intervals for 10 years. Baseline evaluations included semi-structured diagnostic interviews for Axis I and II psychopathology and childhood adversity. Direct interview and family history data were collected on first-degree relatives. Follow-up assessments included the Longitudinal Follow-up Evaluation and Hamilton Depression Rating Scale. Using mixed effects growth curve models, univariate predictors of depression severity and functional impairment at 10-year outcome included older age, less education, concurrent anxiety disorder, greater familial loading for chronic depression, a history of a poorer maternal relationship in childhood, and a history of childhood sexual abuse. In addition, longer duration of dysthymic disorder also predicted greater impairment 10 years later. Predictors of a poorer trajectory of depressive symptoms over time included ethnicity and personality disorders; predictors of a poorer trajectory of social functioning included familial loading of chronic depression and quality of the childhood maternal relationship. Thus, demographic, clinical, family history, and early adversity variables all contribute to predicting the long-term trajectory and outcome of DD. These variables should be routinely assessed in clinical evaluations and can provide clinicians with valuable prognostic information.

[Bioacoustic of the advertisement call of Ceratophrys cranwelli (Anura: Ceratophryidae)].

PubMed

Valetti, Julián Alonso; Salas, Nancy Edith; Martino, Adolfo Ludovico

2013-03-01

The advertisement call plays an important role in the life history of anuran amphibians, mainly during the breeding season. Call features represent an important character to discriminate species, and sound emissions are very effective to assure or reinforce genetic incompatibility, especially in the case of sibling species. Since frogs are ectotherms, acoustic properties of their calls will vary with temperature. In this study, we described the advertisement call of C. cranwelli, quantifying the temperature effect on its components. The acoustic emissions were recorded during 2007 using a DAT record Sony TCD-100 with stereo microphone ECM-MS907 Sony and tape TDK DAT-RGX 60. As males emit their calls floating in temporary ponds, water temperatures were registered after recording the advertisement calls with a digital thermometer TES 1300+/-0.1 degreeC. Altogether, 54 calls from 18 males were analyzed. The temporal variables of each advertisement call were measured using oscillograms and sonograms and the analyses of dominant frequency were performed using a spectrogram. Multiple correlation analysis was used to identify the temperature-dependent acoustic variables and the temperature effect on these variables was quantified using linear regression models. The advertisement call of C. cranwelli consists of a single pulse group. Call duration, Pulse duration and Pulse interval decreased with the temperature, whereas the Pulse rate increased with temperature. The temperature-dependent variables were standardized at 25 degreeC according to the linear regression model obtained. The acoustic variables that were correlated with the temperature are the variables which emissions depend on laryngeal muscles and the temperature constraints the contractile properties of muscles. Our results indicated that temperature explains an important fraction of the variability in some acoustic variables (79% in the Pulse rate), and demonstrated the importance of considering the effect of temperature in acoustic components. The results suggest that acoustic variables show geographic variation to compare data with previous works.

[Changes in heart rate variability after myocardial infarction. Value of Poincareé's diagram].

PubMed

Copie, X; Le Heuzey, J Y; Iliou, M C; Pousset, F; Lavergne, T; Guize, L

1995-11-01

The variability of the heart rate is reduced after myocardial infarction. It then progressively increases, to return to near normal values after several months. However, these changes in heart rate variability occur at the same time as slowing of the heart rate which makes interpretation difficult. Poincaré's diagram is constructed from a Holter recording plotting each RR interval against the preceding RR interval. The authors have developed a geometric approach to this diagram to evaluate parasympathetic tone for a given heart rate. By measuring the dispersion in height of the Poincaré's diagram, the authors evaluate the shor-term variability for a given RR interval. Two 24 hr Holter recordings were performed in 52 patients at one and two weeks after a myocardial infarction. The dispersion in the height of the Poincaré's diagrams was measured at the 10th, 25th, 50th, 75th and 90th percentiles of the total dispersion. The authors have shown an increase in the short-term variability of the shortest RR intervals (1th, 25th and 50th percentiles) which is not observed in the longer RR intervals (75th and 90th percentiles). In conclusion, theres is an increase in the heart rate variability at the shortest RR intervals. This suggests that the recovery of parasympathic tone after myocardial infarction occurs mainly at the fastest heart rates.

Gait profile score and movement analysis profile in patients with Parkinson's disease during concurrent cognitive load

PubMed Central

Speciali, Danielli S.; Oliveira, Elaine M.; Cardoso, Jefferson R.; Correa, João C. F.; Baker, Richard; Lucareli, Paulo R. G.

2014-01-01

Background: Gait disorders are common in individuals with Parkinson's Disease (PD) and the concurrent performance of motor and cognitive tasks can have marked effects on gait. The Gait Profile Score (GPS) and the Movement Analysis Profile (MAP) were developed in order to summarize the data of kinematics and facilitate understanding of the results of gait analysis. Objective: To investigate the effectiveness of the GPS and MAP in the quantification of changes in gait during a concurrent cognitive load while walking in adults with and without PD. Method: Fourteen patients with idiopathic PD and nine healthy subjects participated in the study. All subjects performed single and dual walking tasks. The GPS/MAP was computed from three-dimensional gait analysis data. Results: Differences were found between tasks for GPS (P<0.05) and Gait Variable Score (GVS) (pelvic rotation, knee flexion-extension and ankle dorsiflexion-plantarflexion) (P<0.05) in the PD group. An interaction between task and group was observed for GPS (P<0.01) for the right side (Cohen's ¯d=0.99), left side (Cohen's ¯d=0.91), and overall (Cohen's ¯d=0.88). No interaction was observed only for hip internal-external rotation and foot internal-external progression GVS variables in the PD group. Conclusions: The results showed gait impairment during the dual task and suggest that GPS/MAP may be used to evaluate the effects of concurrent cognitive load while walking in patients with PD. PMID:25054382

Three-dimensional assessment of squats and drop jumps using the Microsoft Xbox One Kinect: Reliability and validity.

PubMed

Mentiplay, Benjamin F; Hasanki, Ksaniel; Perraton, Luke G; Pua, Yong-Hao; Charlton, Paula C; Clark, Ross A

2018-03-01

The Microsoft Xbox One Kinect™ (Kinect V2) contains a depth camera that can be used to manually identify anatomical landmark positions in three-dimensions independent of the standard skeletal tracking, and therefore has potential for low-cost, time-efficient three-dimensional movement analysis (3DMA). This study examined inter-session reliability and concurrent validity of the Kinect V2 for the assessment of coronal and sagittal plane kinematics for the trunk, hip and knee during single leg squats (SLS) and drop vertical jumps (DVJ). Thirty young, healthy participants (age = 23 ± 5yrs, male/female = 15/15) performed a SLS and DVJ protocol that was recorded concurrently by the Kinect V2 and 3DMA during two sessions, one week apart. The Kinect V2 demonstrated good to excellent reliability for all SLS and DVJ variables (ICC ≥ 0.73). Concurrent validity ranged from poor to excellent (ICC = 0.02 to 0.98) during the SLS task, although trunk, hip and knee flexion and two-dimensional measures of knee abduction and frontal plane projection angle all demonstrated good to excellent validity (ICC ≥ 0.80). Concurrent validity for the DVJ task was typically worse, with only two variables exceeding ICC = 0.75 (trunk and hip flexion). These findings indicate that the Kinect V2 may have potential for large-scale screening for ACL injury risk, however future prospective research is required.

Lakes without Landsat? An alternative approach to remote lake monitoring with MODIS 250 m imagery

USGS Publications Warehouse

Ian M. McCullough,; Loftin, Cynthia S.; Steven A. Sader,

2013-01-01

We evaluated use of MODIS 250 m imagery for remote lake monitoring in Maine. Despite limited spectral resolution (visible red and near infrared bands), the twice daily image capture has a potential advantage over conventionally used, often cloudy Landsat imagery (16 day interval) when short time windows are of interest. We analyzed 364 eligible (≥100 ha) Maine lakes during late summer (Aug–early Sep) 2000–2011. The red band was strongly correlated with natural log-transformed Secchi depth (SD), and the addition of ancillary lake and watershed variables explained some variability in ln(SD) (R2= 0.68–0.85; 9 models). Weak spectral resolution and variable lake conditions limited accurate lake monitoring to relatively productive periods in late summer, as indicated by inconsistent, sometimes weak regressions during June and July when lakes were clearer and less stable (R2 = 0.19–0.74; 8 models). Additionally, SD estimates derived from 2 sets of concurrent MODIS and Landsat imagery generally did not agree unless Landsat imagery (30 m) was resampled to 250 m, likely owing to various factors related to scale. Average MODIS estimates exceeded those of Landsat by 0.35 and 0.49 m on the 2 dates. Overall, MODIS 250 m imagery are potentially useful for remote lake monitoring during productive periods when Landsat data are unavailable; however, analyses must occur when algal communities are stable and well-developed, are biased toward large lakes, may overestimate SD, and accuracy may be unreliable without non-spectral lake predictors.

Lakes without Landsat? An alternative approach to remote lake monitoring with MODIS 250 m imagery

USGS Publications Warehouse

Loftin, Cyndy; Ian M. McCullough,; Steven A. Sader,

2013-01-01

We evaluated use of MODIS 250 m imagery for remote lake monitoring in Maine. Despite limited spectral resolution (visible red and near infrared bands), the twice daily image capture has a potential advantage over conventionally used, often cloudy Landsat imagery (16 day interval) when short time windows are of interest. We analyzed 364 eligible (≥100 ha) Maine lakes during late summer (Aug–early Sep) 2000–2011. The red band was strongly correlated with natural log-transformed Secchi depth (SD), and the addition of ancillary lake and watershed variables explained some variability in ln(SD) (R2 = 0.68–0.85; 9 models). Weak spectral resolution and variable lake conditions limited accurate lake monitoring to relatively productive periods in late summer, as indicated by inconsistent, sometimes weak regressions during June and July when lakes were clearer and less stable (R2 = 0.19–0.74; 8 models). Additionally, SD estimates derived from 2 sets of concurrent MODIS and Landsat imagery generally did not agree unless Landsat imagery (30 m) was resampled to 250 m, likely owing to various factors related to scale. Average MODIS estimates exceeded those of Landsat by 0.35 and 0.49 m on the 2 dates. Overall, MODIS 250 m imagery are potentially useful for remote lake monitoring during productive periods when Landsat data are unavailable; however, analyses must occur when algal communities are stable and well-developed, are biased toward large lakes, may overestimate SD, and accuracy may be unreliable without non-spectral lake predictors.

Dynamic Parameters Variability: Time Interval Interference on Ground Reaction Force During Running.

PubMed

Pennone, Juliana; Mezêncio, Bruno; Amadio, Alberto C; Serrão, Júlio C

2016-04-01

The aim of this study was to determine the effect of the time between measures on ground reaction force running variability; 15 healthy men (age = 23.8 ± 3.7 years; weight = 72.8 ± 7.7 kg; height 174.3 ± 8.4 cm) performed two trials of running 45 minutes at 9 km/hr at intervals of seven days. The ground reaction forces were recorded every 5 minutes. The coefficients of variation of indicative parameters of the ground reaction forces for each condition were compared. The coefficients of variations of the ground reaction forces curve analyzed between intervals and sessions were 21.9% and 21.48%, respectively. There was no significant difference for the ground reaction forces parameters Fy1, tFy1, TC1, Imp50, Fy2, and tFy2 between intervals and sessions. Although the ground reaction forces variables present a natural variability, this variability in intervals and in sessions remained consistent, ensuring a high reliability in repeated measures designs. © The Author(s) 2016.

On Correlational Properties for Volcanic Earthquakes Associated with Asamayama (Japan), 1983-2005

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reyment, Richard A.

To a first approximation, earthquakes directly associated with volcanic activity may be studied as point-stochastic processes. The earthquakes associated with B-type (movements located at 1 km or shallower) eruptive activity in the caldera of Asamayama differ in correlational properties from concurrent deep-seated seismic activity (A-type, located deeper than approximately 1 km). A-type activity occurs either in the form of independently distributed intervals between events or as dependently distributed intervals which are most appropriately analysed in contiguous sub-samples ('windows'). The cross correlations between the magnitudes of A-type earthquakes and depth of events for three periods from 1983 to 2005 may bemore » of significance for interpreting aspects of the volcanic history of Asamayama. The lag-1 serial correlation coefficient for the A-type sequence from 1983 to 1990 is not significantly different from zero. In the case of the sets for 1991-2002 and 2003-2005, the coefficients are small but not zero. The difference is in part, at least, probably due to the well-known confounding effect of trending as opposed to true serial correlation between successive events. The serial correlation coefficient for the B-type crater sequence is not significant. The novel aspect of the present study concerns the relationship between depth of A-type earth movements and magnitude of associated shocks.« less

Evaluating psychological markers for human nicotine dependence: tobacco choice, extinction, and Pavlovian-to-instrumental transfer.

PubMed

Hogarth, Lee; Chase, Henry W

2012-06-01

Individual differences in drug dependence may be mediated by several abnormalities in associative learning, including perseveration of drug-seeking following contingency change, greater control over drug-seeking by Pavlovian stimuli, or greater sensitivity to drug reinforcement establishing higher rates of drug-seeking. To evaluate these three candidate markers for nicotine dependence, Experiment 1 contrasted daily (N = 22) and nondaily smoker groups (N = 22) on a novel instrumental learning task, where one S+ was first trained as a predictor of tobacco reward before being extinguished. Experiment 2 compared daily (N = 18) and nondaily smoker groups (N = 18) on a concurrent-choice task for tobacco and chocolate reward before an extinction test in which the tobacco response was extinguished, followed by a Pavlovian-to-instrumental transfer test, wherein the impact of tobacco and chocolate cues on concurrent choice was measured (gender was balanced within each smoker group). The results showed no group difference in sensitivity to extinction of either the stimulus-drug or response-drug contingency in Experiments 1 and 2, respectively, nor did groups show a difference in Pavlovian-to-instrumental transfer of control over tobacco choice. By contrast, nicotine-dependence status was marked by a higher frequency of tobacco choice in the concurrent-choice procedure, and this choice preference was associated with subjective craving (gender did not affect any behavioral measure). These results favor the view that nicotine dependence in this sample is not determined by individual predilection for perseveration or stimulus-control over drug-seeking, but by greater sensitivity to reinforcement of instrumental drug choice. Value-based decision theories of dependence are discussed.

Employment-based reinforcement of adherence to an FDA approved extended release formulation of naltrexone in opioid-dependent adults: a randomized controlled trial.

PubMed

DeFulio, Anthony; Everly, Jeffrey J; Leoutsakos, Jeannie-Marie S; Umbricht, Annie; Fingerhood, Michael; Bigelow, George E; Silverman, Kenneth

2012-01-01

Naltrexone provides excellent opioid blockade, but its clinical utility is limited because opioid-dependent patients typically refuse it. An injectable suspension of naltrexone for extended release (XR-NTX) was recently approved by the FDA for treatment of opioid dependence. XR-NTX treatment may require concurrent behavioral intervention to maximize adherence and effectiveness, thus we sought to evaluate employment-based reinforcement as a method of improving adherence to XR-NTX in opiate dependent adults. Opioid-dependent adults (n=38) were detoxified and inducted onto oral naltrexone, then randomly assigned to contingency or prescription conditions. Participants received up to six doses of XR-NTX at four-week intervals. All participants could earn vouchers for attendance and performance at a therapeutic workplace. Contingency participants were required to accept XR-NTX injections to access the workplace and earn vouchers. Prescription participants could earn vouchers independent of their acceptance of XR-NTX injections. Contingency participants accepted significantly more naltrexone injections than prescription participants (87% versus 52%, p=.002), and were more likely to accept all injections (74% versus 26%, p=.004). Participants in the two conditions provided similar percentages of samples negative for opiates (72% versus 65%) and for cocaine (58% versus 54%). Opiate positivity was significantly more likely when samples were also cocaine positive, independent of naltrexone blockade (p=.002). Long-term adherence to XR-NTX in unemployed opiate dependent adults is low under usual care conditions. Employment-based reinforcement can maintain adherence to XR-NTX. Ongoing cocaine use appears to interfere with the clinical effectiveness of XR-NTX on opiate use. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Biological Variability in Serum Cortisol Concentration Post-adrenocorticotropic Hormone Stimulation in Healthy Dogs.

PubMed

Gal, A; Weidgraaf, K; Bowden, J P; Lopez-Villalobos, N; Cave, N J; Chambers, J P; Castillo-Alcala, F

2017-05-01

The ACTH stimulation has low sensitivity for the diagnosis of hypercortisolism possibly as a result of biological and analytical variability. To report the components of biological and analytical variability in serum cortisol concentration post-ACTH stimulation ([cortisol]) in healthy dogs. Fourteen healthy harrier hound dogs. The data were extracted from a separate, prospective, randomized, double-blinded, controlled discovery study in which dogs treated with vehicle control and 4 different doses of cortisone acetate (CA) for 7 days had an ACTH stimulation test performed to confirm the dose-dependent effect of CA. The index of individuality (IoI), the critical difference between sequential measurements (C D ), and the number of measurements required to assess the homeostatic set point (HSP) of [cortisol] with confidence intervals (CI) of 90 and 95% were estimated. The IoI was equal to 1.1 and the C D was 3.3 μg/dL (92 nmol/L). The number of measurements required to assess the HSP of [cortisol] with CI of 90 and 95% were 3 and 15, respectively. Additionally, mean [cortisol] was higher in males than in females (13.3 ± 4 μg/dL [366 ± 114 nmol/L] vs. 11.5 ± 2.5 μg/dL [318 ± 65 nmol/L], respectively; P = .046). As expected, treatment with CA resulted in a dose-dependent suppression of [cortisol]. False-negative test results in hypercortisolism could occur when [cortisol] is outside of the individual's HSP and within the reference interval. The large C D emphasizes the importance of assessing clinically relevant parameters in the diagnosis and monitoring of HC. Copyright © 2017 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

Age-related changes in the bimanual advantage and in brain oscillatory activity during tapping movements suggest a decline in processing sensory reafference.

PubMed

Sallard, Etienne; Spierer, Lucas; Ludwig, Catherine; Deiber, Marie-Pierre; Barral, Jérôme

2014-02-01

Deficits in the processing of sensory reafferences have been suggested as accounting for age-related decline in motor coordination. Whether sensory reafferences are accurately processed can be assessed based on the bimanual advantage in tapping: because of tapping with an additional hand increases kinesthetic reafferences, bimanual tapping is characterized by a reduced inter-tap interval variability than unimanual tapping. A suppression of the bimanual advantage would thus indicate a deficit in sensory reafference. We tested whether elderly indeed show a reduced bimanual advantage by measuring unimanual (UM) and bimanual (BM) self-paced tapping performance in groups of young (n = 29) and old (n = 27) healthy adults. Electroencephalogram was recorded to assess the underlying patterns of oscillatory activity, a neurophysiological mechanism advanced to support the integration of sensory reafferences. Behaviorally, there was a significant interaction between the factors tapping condition and age group at the level of the inter-tap interval variability, driven by a lower variability in BM than UM tapping in the young, but not in the elderly group. This result indicates that in self-paced tapping, the bimanual advantage is absent in elderly. Electrophysiological results revealed an interaction between tapping condition and age group on low beta band (14-20 Hz) activity. Beta activity varied depending on the tapping condition in the elderly but not in the young group. Source estimations localized this effect within left superior parietal and left occipital areas. We interpret our results in terms of engagement of different mechanisms in the elderly depending on the tapping mode: a 'kinesthetic' mechanism for UM and a 'visual imagery' mechanism for BM tapping movement.

Arsenic disulfide induced apoptosis and concurrently promoted erythroid differentiation in cytokine-dependent myelodysplastic syndrome-progressed leukemia cell line F-36p with complex karyotype including monosomy 7.

PubMed

Hu, Xiao-mei; Tanaka, Sachiko; Onda, Kenji; Yuan, Bo; Toyoda, Hiroo; Ma, Rou; Liu, Feng; Hirano, Toshihiko

2014-05-01

Acute myeloid leukemia progressed from myelodysplastic syndrome (MDS/AML) is generally incurable with poor prognosis for complex karyotype including monosomy 7 (-7). Qinghuang Powder (, QHP), which includes Qing Dai (Indigo naturalis) and Xiong Huang (realgar) in the formula, is effective in treating MDS or MDS/AML even with the unfavorable karyotype, and its therapeutic efficacy could be enhanced by increasing the Xiong huang content in the formula, while Xiong huang contains > 90% arsenic disulfide (As2S2). F-36p cell line was established from a MDS/AML patient with complex karyotype including -7, and was in cytokine-dependent. The present study was to investigate the effects of As2S2 on F-36p cells. Cell proliferation was measured by an 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Cell apoptosis was identified by Annexin V-staining. Cell viability was determined by a propidium iodide (PI) exclusion. Erythroid differentiation was evaluated by the expression of cell surface antigen CD235a (GpA). After treatment with As2S2 at concentrations of 0.5 to 16 μmol/L for 72 h, As2S2 inhibited the proliferation of F-36p cells. The 50% inhibitory concentrations (IC50) of As2S2 against the proliferation of F-36p cells was 6 μmol/L. The apoptotic cells significantly increased in a dose-dependent mannar (P<0.05). The cell viabilities were significantly inhibited by As2S2 dose-dependent in a dose-dependent manner (P<0.05). Significant increases of CD235a-positive cells were concurrently observed (P<0.05) also in a dose-dependent manner. As2S2 could inhibit proliferation and viability, induce apoptosis, and concurrently promote erythroid differentiation dose-dependently in F-36p cells. As2S2 can inhibit proliferation and viability, induce apoptosis, and concurrently promote erythroid differentiation in cytokine-dependent MDS-progressed human leukemia cell line F-36p with complex karyotype including -7. The data suggest that QHP and/or As2S2 could be a potential candidate in the treatment of MDS or MDS/AML even with unfavorable cytogenetics.

Modelling and simulating decision processes of linked lives: An approach based on concurrent processes and stochastic race.

PubMed

Warnke, Tom; Reinhardt, Oliver; Klabunde, Anna; Willekens, Frans; Uhrmacher, Adelinde M

2017-10-01

Individuals' decision processes play a central role in understanding modern migration phenomena and other demographic processes. Their integration into agent-based computational demography depends largely on suitable support by a modelling language. We are developing the Modelling Language for Linked Lives (ML3) to describe the diverse decision processes of linked lives succinctly in continuous time. The context of individuals is modelled by networks the individual is part of, such as family ties and other social networks. Central concepts, such as behaviour conditional on agent attributes, age-dependent behaviour, and stochastic waiting times, are tightly integrated in the language. Thereby, alternative decisions are modelled by concurrent processes that compete by stochastic race. Using a migration model, we demonstrate how this allows for compact description of complex decisions, here based on the Theory of Planned Behaviour. We describe the challenges for the simulation algorithm posed by stochastic race between multiple concurrent complex decisions.

Short- and Long-Term Effects of Concurrent Strength and HIIT Training in Octogenarians with COPD.

PubMed

Guadalupe-Grau, Amelia; Aznar-Laín, Susana; Mañas, Asier; Castellanos, Juan; Alcázar, Julián; Ara, Ignacio; Mata, Esmeralda; Daimiel, Rosa; García-García, Francisco José

2017-01-01

To investigate the short- and long-term effects of concurrent strength and high-intensity interval training (HIIT) on octogenarian COPD patients, nine males (age = 84.2 ± 2.8 years, BMI = 29.3 ± 2.3) with low to severe COPD levels (2.1 ± 1.5 BODE index) underwent a supervised 9-week strength and HIIT exercise program. Training had a significant (p < .05) impact on senior fitness test scores (23-45%), 30-m walking speed (from 1.29 ± 0.29-1.62 ± 0.33 m/s), leg and chest press 1RM (38% and 45% respectively), maximal isometric strength (30-35%), and 6-min walking test (from 286.1 ± 107.2-396.2 ± 106.5 m), and tended to increase predicted forced vital capacity by 14% (p = .07). One year after the intervention all training-induced gains returned to their preintervention values except for the chest press 1RM (p <.05). Short-term concurrent strength and HIIT training increases physical fitness in the oldest-old COPD patients, and has potential long-term benefits.

Concurrent validity and reliability of the Simple Goniometer iPhone app compared with the Universal Goniometer.

PubMed

Jones, Anne; Sealey, Rebecca; Crowe, Michael; Gordon, Susan

2014-10-01

The aim of this study was to assess the concurrent validity and reliability of the Simple Goniometer (SG) iPhone® app compared to the Universal Goniometer (UG). Within subject comparison design comparing the UG with the SG app. James Cook University, Townsville, Queensland, Australia. Thirty-six volunteer participants, with a mean age of 60.6 years (SD 6.2). Not applicable. Thirty-six participants performed three standing lunges during which the knee joint angle was measured with the SG app and the UG. There were no significant differences in the measures of individual knee joint angles between the UG and the SG app. Pearson correlations of 0.96-0.98 and intraclass correlation coefficients of 0.97-0.99 (95% confidence interval: 0.95-1.00) were recorded for all measures. Using the Bland-Altman method, the standard error of the mean of the differences and the standard deviation of the mean of the differences were low. The measurements from the SG iPhone® app were reliable and possessed concurrent validity for this sample and protocol when compared to the UG.

Mesh choice in ventral hernia repair: so many choices, so little time.

PubMed

Le, Dinh; Deveney, Clifford W; Reaven, Nancy L; Funk, Susan E; McGaughey, Karen J; Martindale, Robert G

2013-05-01

Currently, >200 meshes are commercially available in the United States. To help guide appropriate mesh selection, the investigators examined the postsurgical experiences of all patients undergoing ventral hernia repair at their facility from 2008 to 2011 with ≥12 months of follow-up. A retrospective review of prospectively collected data was conducted. All returns (surgical readmission, office or emergency visit) for complications or recurrences were examined. The impact of demographics (age, gender, and body mass index [BMI]), risk factors (hernia grade, hernia size, concurrent and past bariatric surgery, concurrent and past organ transplantation, any concurrent surgery, and American Society of Anesthesiologists score), and prosthetic type (polypropylene, other synthetic, human acellular dermal matrix, non-cross-linked porcine-derived acellular dermal matrix, other biologic, or none) on the frequency of return was evaluated. A total of 564 patients had 12 months of follow-up, and 417 patients had 18 months of follow-up. In a univariate regression analysis, study arm (biologic, synthetic, or primary repair), hernia grade, hernia size, past bariatric surgery, and American Society of Anesthesiologists score were significant predictors of recurrence (P < .05). Multivariate analysis, stepwise regression, and interaction tests identified three variables with significant predictive power: hernia grade, hernia size, and BMI. The adjusted odds ratios vs hernia grade 2 for surgical readmission were 2.6 (95% confidence interval [CI], 1.3 to 5.1) for grade 3 and 2.6 (95% CI, 1.1 to 6.4) for grade 4 at 12 months and 2.3 (95% CI, 1.1 to 4.6) for grade 3 and 4.2 (95% CI, 1.7 to 10.0) for grade 4 at 18 months. Large hernia size (adjusted odds ratio vs small size, 3.2; 95% CI, 1.6 to 6.2) and higher BMI (adjusted odds ratio for BMI ≥50 vs 30 to 34.99 kg/m(2), 5.7; 95% CI, 1.2 to 26.2) increased the likelihood of surgical readmission within 12 months. The present data support the hypothesis that careful matching of patient characteristics to choice of prosthetic will minimize complications, readmissions, and the number of postoperative office visits. Copyright © 2013 Elsevier Inc. All rights reserved.

Potential controls of isoprene in the surface ocean

NASA Astrophysics Data System (ADS)

Hackenberg, S. C.; Andrews, S. J.; Airs, R.; Arnold, S. R.; Bouman, H. A.; Brewin, R. J. W.; Chance, R. J.; Cummings, D.; Dall'Olmo, G.; Lewis, A. C.; Minaeian, J. K.; Reifel, K. M.; Small, A.; Tarran, G. A.; Tilstone, G. H.; Carpenter, L. J.

2017-04-01

Isoprene surface ocean concentrations and vertical distribution, atmospheric mixing ratios, and calculated sea-to-air fluxes spanning approximately 125° of latitude (80°N-45°S) over the Arctic and Atlantic Oceans are reported. Oceanic isoprene concentrations were associated with a number of concurrently monitored biological variables including chlorophyll a (Chl a), photoprotective pigments, integrated primary production (intPP), and cyanobacterial cell counts, with higher isoprene concentrations relative to all respective variables found at sea surface temperatures greater than 20°C. The correlation between isoprene and the sum of photoprotective carotenoids, which is reported here for the first time, was the most consistent across all cruises. Parameterizations based on linear regression analyses of these relationships perform well for Arctic and Atlantic data, producing a better fit to observations than an existing Chl a-based parameterization. Global extrapolation of isoprene surface water concentrations using satellite-derived Chl a and intPP reproduced general trends in the in situ data and absolute values within a factor of 2 between 60% and 85%, depending on the data set and algorithm used.

Improving National Results in Liver Transplantation Using Grafts From Donation After Cardiac Death Donors.

PubMed

Croome, Kristopher P; Lee, David D; Keaveny, Andrew P; Taner, C Burcin

2016-12-01

Published reports describing the national experience with liver grafts from donation after cardiac death (DCD) donors have resulted in reservations with their widespread utilization. The present study aimed to investigate if temporal improvements in outcomes have been observed on a national level and to determine if donor and recipient selection have been modified in a fashion consistent with published data on DCD use in liver transplantation (LT). Patients undergoing DCD LT between 2003 and 2014 were obtained from the United Network of Organ Sharing Standard Transplant Analysis and Research file and divided into 3 equal eras based on the date of DCD LT: era 1 (2003-2006), era 2 (2007-2010), and era 3 (2011-2014). Improvement in graft survival was seen between era 1 and era 2 (P = 0.001) and between era 2 and era 3 (P < 0.001). Concurrently, an increase in the proportion of patients with hepatocellular carcinoma and a decrease in critically ill patients, retransplant recipients, donor age, warm ischemia time greater than 30 minutes and cold ischemic time also occurred over the same period. On multivariate analysis, significant predictors of graft survival included: recipient age, biologic MELD score, recipient on ventilator, recipient hepatitis C virus + serology, donor age and cold ischemic time. In addition, even after adjustment for all of the aforementioned variables, both era 2 (hazard ratio, 0.81; confidence interval, 0.69-0.94; P = 0.007), and era 3 (hazard ratio, 0.61; confidence interval, 0.5-0.73; P < 0.001) had a protective effect compared to era 1. The national outcomes for DCD LT have improved over the last 12 years. This change was associated with modifications in both recipient and donor selection. Furthermore, an era effect was observed, even after adjustment for all recipient and donor variables on multivariate analysis.

Cardiac Autonomic Responses during Exercise and Post-exercise Recovery Using Heart Rate Variability and Systolic Time Intervals-A Review.

PubMed

Michael, Scott; Graham, Kenneth S; Davis, Glen M

2017-01-01

Cardiac parasympathetic activity may be non-invasively investigated using heart rate variability (HRV), although HRV is not widely accepted to reflect sympathetic activity. Instead, cardiac sympathetic activity may be investigated using systolic time intervals (STI), such as the pre-ejection period. Although these autonomic indices are typically measured during rest, the "reactivity hypothesis" suggests that investigating responses to a stressor (e.g., exercise) may be a valuable monitoring approach in clinical and high-performance settings. However, when interpreting these indices it is important to consider how the exercise dose itself (i.e., intensity, duration, and modality) may influence the response. Therefore, the purpose of this investigation was to review the literature regarding how the exercise dosage influences these autonomic indices during exercise and acute post-exercise recovery. There are substantial methodological variations throughout the literature regarding HRV responses to exercise, in terms of exercise protocols and HRV analysis techniques. Exercise intensity is the primary factor influencing HRV, with a greater intensity eliciting a lower HRV during exercise up to moderate-high intensity, with minimal change observed as intensity is increased further. Post-exercise, a greater preceding intensity is associated with a slower HRV recovery, although the dose-response remains unclear. A longer exercise duration has been reported to elicit a lower HRV only during low-moderate intensity and when accompanied by cardiovascular drift, while a small number of studies have reported conflicting results regarding whether a longer duration delays HRV recovery. "Modality" has been defined multiple ways, with limited evidence suggesting exercise of a greater muscle mass and/or energy expenditure may delay HRV recovery. STI responses during exercise and recovery have seldom been reported, although limited data suggests that intensity is a key determining factor. Concurrent monitoring of HRV and STI may be a valuable non-invasive approach to investigate autonomic stress reactivity; however, this integrative approach has not yet been applied with regards to exercise stressors.

Applicability of Type A/B alcohol dependence in the general population.

PubMed

Tam, Tammy W; Mulia, Nina; Schmidt, Laura A

2014-05-01

This study examined the concurrent and predictive validity of Type A/B alcohol dependence in the general population-a typology developed in clinical populations to gauge severity of dependence. Data were drawn from Waves 1 and 2 of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC). The sample included 1,172 alcohol-dependent drinkers at baseline who were reinterviewed three years later. Latent class analysis was used to derive Type A/B classification using variables replicating the original Type A/B typology. Predictive validity of the Type A/B classification was assessed by multivariable linear and logistic regressions. A two-class solution consistent with Babor's original Type A/B typology adequately fit the data. Type B alcoholics in the general population, compared to Type As, had higher alcohol severity and more co-occurring drug, mental, and physical health problems. In the absence of treatment services utilization, Type B drinkers had two times the odds of being alcohol dependent three years later. Among those who utilized alcohol treatment services, Type B membership was predictive of heavy drinking and drug dependence, but not alcohol dependence, three years later. Findings suggest that Type A/B classification is both generalizable to, and valid within, the US general population of alcohol dependent drinkers. Results highlight the value of treatment for mitigating the persistence of dependence among Type B alcoholics in the general population. Screening for markers of vulnerability to Type B dependence could be of clinical value for health care providers to determine appropriate intervention. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

The Education of Attention as Explanation of Variability of Practice Effects : Learning the Final Approach Phase in a Flight Simulator

ERIC Educational Resources Information Center

Huet, Michael; Jacobs, David M.; Camachon, Cyril; Missenard, Olivier; Gray, Rob; Montagne, Gilles

2011-01-01

The present study reports two experiments in which a total of 20 participants without prior flight experience practiced the final approach phase in a fixed-base simulator. All participants received self-controlled concurrent feedback during 180 practice trials. Experiment 1 shows that participants learn more quickly under variable practice…

Long-term exercising video-endoscopic examination of the upper airway following laryngoplasty surgery: a prospective cross-sectional study of 41 horses.

PubMed

Barnett, T P; O'Leary, J M; Parkin, T D H; Dixon, P M; Barakzai, S Z

2013-09-01

To investigate upper respiratory tract function in horses, previously undergoing laryngoplasty (LP), using exercising video-endoscopy. To evaluate arytenoid abduction and stability, diagnose any concurrent upper airway problems, and correlate these with the owners' perception of success. Horses undergoing LP during a 6-year period at one hospital were initially included. Those available for re-examination were exercised for a duration and intensity considered maximal for their discipline using an over-ground endoscope. Resting and exercising laryngeal and pharyngeal videos were analysed blindly. Multivariable analysis was used to test associations between resting and exercising endoscopic variables, and also between endoscopic variables and owner questionnaire findings. Forty-one horses were included and 78% had a form of upper airway collapse at exercise, with 41% having complex forms, despite 93% of owners reporting the surgery to have been beneficial. Horses with poor abduction (grades 4 or 5/5) were 6 times more likely to make respiratory noise compared with those with good (grades 2 or 3/5) abduction (P = 0.020; 95% confidence interval [CI] 1.3-27.0), and those not having a ventriculectomy were 4.9 times more likely to produce respiratory noise post operatively (P = 0.048; 95% CI 1.0-23.9). Palatal dysfunction was observed in 24% of horses at rest, and 56% at exercise, with the diagnosis at rest and exercise significantly associated (P = 0.001). Increasing severity of pharyngeal lymphoid hyperplasia (prevalence 61%) was significantly associated with increasing arytenoid abduction (P = 0.01). Thirty-four per cent of horses had aryepiglottic fold collapse and 22% of horses had vocal fold collapse. Many horses that had previously had LP were diagnosed with upper airway abnormalities, despite the procedure being considered as beneficial by most owners. When investigating cases of ongoing respiratory noise or poor performance following LP, exercising endoscopy must be considered. Continued respiratory noise may be associated with poor arytenoid abduction and not performing concurrent ventriculectomy. © 2012 EVJ Ltd.

Chemoradiotherapy enhanced the efficacy of radiotherapy in nasopharyngeal carcinoma patients: a network meta-analysis

PubMed Central

He, Jian; Wu, Ping; Tang, Yaoyun; Liu, Sulai; Xie, Chubo; Luo, Shi; Zeng, Junfeng; Xu, Jing; Zhao, Suping

2017-01-01

Object A Bayesian network meta-analysis (NMA) was conducted to estimate the overall survival (OS) and complete response (CR) performance in nasopharyngeal carcinoma (NPC) patients who have been given the treatment of radiotherapy, concurrent chemoradiotherapy (C), adjuvant chemotherapy (A), neoadjuvant chemotherapy (N), concurrent chemoradiotherapy with adjuvant chemotherapy (C+A), concurrent chemoradiotherapy with neoadjuvant chemotherapy (C+N) and neoadjuvant chemotherapy with adjuvant chemotherapy (N+A). Methods Literature search was conducted in electronic databases. Hazard ratios (HRs) accompanied their 95% confidence intervals (95%CIs) or 95% credible intervals (95%CrIs) were applied to measure the relative survival benefit between two comparators. Meanwhile odd ratios (ORs) with their 95% CIs or CrIs were given to present CR data from individual studies. RESULTS Totally 52 qualified studies with 10,081 patients were included in this NMA. In conventional meta-analysis (MA), patients with N+C exhibited an average increase of 9% in the 3-year OS in relation to those with C+A. As for the NMA results, five therapies were associated with a significantly reduced HR when compared with the control group when concerning 5-year OS. C, C+A and N+A also presented a decreased HR compared with A. There was continuity among 1-year, 3-year and 5-year OS status. Cluster analysis suggested that the three chemoradiotherapy appeared to be divided into the most compete group which is located in the upper right corner of the cluster plot. Conclusion In view of survival rate and complete response, the NMA results revealed that C, C+A and C+N showed excellent efficacy. As a result, these 3 therapies were supposed to be considered as the first-line treatment according to this NMA. PMID:28418901

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jeong, J; Deasy, J O

Purpose: Concurrent chemo-radiation therapy (CCRT) has become a more common cancer treatment option with a better tumor control rate for several tumor sites, including head and neck and lung cancer. In this work, possible optimal chemotherapy schedules were investigated by implementing chemotherapy cell-kill into a tumor response model of RT. Methods: The chemotherapy effect has been added into a published model (Jeong et al., PMB (2013) 58:4897), in which the tumor response to RT can be simulated with the effects of hypoxia and proliferation. Based on the two-compartment pharmacokinetic model, the temporal concentration of chemotherapy agent was estimated. Log cell-killmore » was assumed and the cell-kill constant was estimated from the observed increase in local control due to concurrent chemotherapy. For a simplified two cycle CCRT regime, several different starting times and intervals were simulated with conventional RT regime (2Gy/fx, 5fx/wk). The effectiveness of CCRT was evaluated in terms of reduction in radiation dose required for 50% of control to find the optimal chemotherapy schedule. Results: Assuming the typical slope of dose response curve (γ50=2), the observed 10% increase in local control rate was evaluated to be equivalent to an extra RT dose of about 4 Gy, from which the cell-kill rate of chemotherapy was derived to be about 0.35. Best response was obtained when chemotherapy was started at about 3 weeks after RT began. As the interval between two cycles decreases, the efficacy of chemotherapy increases with broader range of optimal starting times. Conclusion: The effect of chemotherapy has been implemented into the resource-conservation tumor response model to investigate CCRT. The results suggest that the concurrent chemotherapy might be more effective when delayed for about 3 weeks, due to lower tumor burden and a larger fraction of proliferating cells after reoxygenation.« less

The Behavioral Economics of Choice and Interval Timing

PubMed Central

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

2009-01-01

We propose a simple behavioral economic model (BEM) describing how reinforcement and interval timing interact. The model assumes a Weber-law-compliant logarithmic representation of time. Associated with each represented time value are the payoffs that have been obtained for each possible response. At a given real time, the response with the highest payoff is emitted. The model accounts for a wide range of data from procedures such as simple bisection, metacognition in animals, economic effects in free-operant psychophysical procedures and paradoxical choice in double-bisection procedures. Although it assumes logarithmic time representation, it can also account for data from the time-left procedure usually cited in support of linear time representation. It encounters some difficulties in complex free-operant choice procedures, such as concurrent mixed fixed-interval schedules as well as some of the data on double bisection, that may involve additional processes. Overall, BEM provides a theoretical framework for understanding how reinforcement and interval timing work together to determine choice between temporally differentiated reinforcers. PMID:19618985

Schedule-induced drinking as functions of interpellet interval and draught size in the Java macaque1

PubMed Central

Allen, Joseph D.; Kenshalo, Dan R.

1978-01-01

Three Java monkeys received food pellets that were assigned by both ascending and descending series of fixed-time schedules whose values varied between 8 and 256 seconds. The draught size dispensed by a concurrently available water-delivery tube was systematically varied between 1.0 and 0.3 milliliter per lick at various fixed-time values during the second and third series determinations. Session water intake was bitonically related to the interpellet interval and was determined by the interaction of (1) the probability of initiating a drinking bout, which fell off at the highest interpellet intervals and, (2) the size of the bout, which increased directly with increases in interpellet interval. Variations in draught size had little effect on total session intakes, but reduced bout size at draught sizes of 0.5 milliliter and below. Thus, a volume-regulation process of schedule-induced drinking operated generally at the session-intake level, but was limited to higher draught sizes at the bout level. PMID:16812093

Schedule-induced drinking as functions of interpellet interval and draught size in the Java macaque.

PubMed

Allen, J D; Kenshalo, D R

1978-09-01

Three Java monkeys received food pellets that were assigned by both ascending and descending series of fixed-time schedules whose values varied between 8 and 256 seconds. The draught size dispensed by a concurrently available water-delivery tube was systematically varied between 1.0 and 0.3 milliliter per lick at various fixed-time values during the second and third series determinations. Session water intake was bitonically related to the interpellet interval and was determined by the interaction of (1) the probability of initiating a drinking bout, which fell off at the highest interpellet intervals and, (2) the size of the bout, which increased directly with increases in interpellet interval. Variations in draught size had little effect on total session intakes, but reduced bout size at draught sizes of 0.5 milliliter and below. Thus, a volume-regulation process of schedule-induced drinking operated generally at the session-intake level, but was limited to higher draught sizes at the bout level.

Resource Supply Overrides Temperature as a Controlling Factor of Marine Phytoplankton Growth

PubMed Central

Marañón, Emilio; Cermeño, Pedro; Huete-Ortega, María; López-Sandoval, Daffne C.; Mouriño-Carballido, Beatriz; Rodríguez-Ramos, Tamara

2014-01-01

The universal temperature dependence of metabolic rates has been used to predict how ocean biology will respond to ocean warming. Determining the temperature sensitivity of phytoplankton metabolism and growth is of special importance because this group of organisms is responsible for nearly half of global primary production, sustains most marine food webs, and contributes to regulate the exchange of CO2 between the ocean and the atmosphere. Phytoplankton growth rates increase with temperature under optimal growth conditions in the laboratory, but it is unclear whether the same degree of temperature dependence exists in nature, where resources are often limiting. Here we use concurrent measurements of phytoplankton biomass and carbon fixation rates in polar, temperate and tropical regions to determine the role of temperature and resource supply in controlling the large-scale variability of in situ metabolic rates. We identify a biogeographic pattern in phytoplankton metabolic rates, which increase from the oligotrophic subtropical gyres to temperate regions and then coastal waters. Variability in phytoplankton growth is driven by changes in resource supply and appears to be independent of seawater temperature. The lack of temperature sensitivity of realized phytoplankton growth is consistent with the limited applicability of Arrhenius enzymatic kinetics when substrate concentrations are low. Our results suggest that, due to widespread resource limitation in the ocean, the direct effect of sea surface warming upon phytoplankton growth and productivity may be smaller than anticipated. PMID:24921945

Remote Entanglement by Coherent Multiplication of Concurrent Quantum Signals

NASA Astrophysics Data System (ADS)

Roy, Ananda; Jiang, Liang; Stone, A. Douglas; Devoret, Michel

2015-10-01

Concurrent remote entanglement of distant, noninteracting quantum entities is a crucial function for quantum information processing. In contrast with the existing protocols which employ the addition of signals to generate entanglement between two remote qubits, the continuous variable protocol we present is based on the multiplication of signals. This protocol can be straightforwardly implemented by a novel Josephson junction mixing circuit. Our scheme would be able to generate provable entanglement even in the presence of practical imperfections: finite quantum efficiency of detectors and undesired photon loss in current state-of-the-art devices.

Resistance to Extinction Following Variable-Interval Reinforcement: Reinforcer Rate and Amount

ERIC Educational Resources Information Center

Shull, Richard L.; Grimes, Julie A.

2006-01-01

Rats obtained food-pellet reinforcers by nose poking a lighted key. Experiment 1 examined resistance to extinction following single-schedule training with different variable-interval schedules, ranging from a mean interval of 16 min to 0.25 min. That is, for each schedule, the rats received 20 consecutive daily baseline sessions and then a session…

Manipulating measurement scales in medical statistical analysis and data mining: A review of methodologies

PubMed Central

Marateb, Hamid Reza; Mansourian, Marjan; Adibi, Peyman; Farina, Dario

2014-01-01

Background: selecting the correct statistical test and data mining method depends highly on the measurement scale of data, type of variables, and purpose of the analysis. Different measurement scales are studied in details and statistical comparison, modeling, and data mining methods are studied based upon using several medical examples. We have presented two ordinal–variables clustering examples, as more challenging variable in analysis, using Wisconsin Breast Cancer Data (WBCD). Ordinal-to-Interval scale conversion example: a breast cancer database of nine 10-level ordinal variables for 683 patients was analyzed by two ordinal-scale clustering methods. The performance of the clustering methods was assessed by comparison with the gold standard groups of malignant and benign cases that had been identified by clinical tests. Results: the sensitivity and accuracy of the two clustering methods were 98% and 96%, respectively. Their specificity was comparable. Conclusion: by using appropriate clustering algorithm based on the measurement scale of the variables in the study, high performance is granted. Moreover, descriptive and inferential statistics in addition to modeling approach must be selected based on the scale of the variables. PMID:24672565

Human-arm-and-hand-dynamic model with variability analyses for a stylus-based haptic interface.

PubMed

Fu, Michael J; Cavuşoğlu, M Cenk

2012-12-01

Haptic interface research benefits from accurate human arm models for control and system design. The literature contains many human arm dynamic models but lacks detailed variability analyses. Without accurate measurements, variability is modeled in a very conservative manner, leading to less than optimal controller and system designs. This paper not only presents models for human arm dynamics but also develops inter- and intrasubject variability models for a stylus-based haptic device. Data from 15 human subjects (nine male, six female, ages 20-32) were collected using a Phantom Premium 1.5a haptic device for system identification. In this paper, grip-force-dependent models were identified for 1-3-N grip forces in the three spatial axes. Also, variability due to human subjects and grip-force variation were modeled as both structured and unstructured uncertainties. For both forms of variability, the maximum variation, 95 %, and 67 % confidence interval limits were examined. All models were in the frequency domain with force as input and position as output. The identified models enable precise controllers targeted to a subset of possible human operator dynamics.

Associations between psychological constructs and cardiac biomarkers following acute coronary syndrome

PubMed Central

Celano, Christopher M.; Beale, Eleanor E.; Beach, Scott R.; Belcher, Arianna M.; Suarez, Laura; Motiwala, Shweta R.; Gandhi, Parul U.; Gaggin, Hanna; Januzzi, James L.; Healy, Brian C.; Huffman, Jeff C.

2016-01-01

Objective Psychological constructs are associated with cardiovascular health, but the biological mechanisms mediating these relationships are unknown. We examined relationships between psychological constructs and markers of inflammation, endothelial function, and myocardial strain in a cohort of post-acute coronary syndrome (ACS) patients. Methods Participants (N=164) attended study visits 2 weeks and 6 months post-ACS. During these visits, they completed self-report measures of depressive symptoms, anxiety, optimism, and gratitude, and blood samples were collected for measurement of biomarkers reflecting inflammation, endothelial function, and myocardial strain. Generalized estimating equations and linear regression analyses were performed to examine concurrent and prospective relationships between psychological constructs and biomarkers. Results In concurrent analyses, depressive symptoms were associated with elevated markers of inflammation (interleukin-17: β=.047, 95% confidence interval [.010, .083]), endothelial dysfunction (endothelin-1: β=.020, [.004, .037]), and myocardial strain (N-terminal pro-B-type natriuretic peptide: β=.045, [.008, .083]), independent of age, sex, medical variables, and anxiety, while anxiety was not associated with these markers in multivariable adjusted models. Optimism and gratitude were associated with lower levels of markers of endothelial dysfunction (endothelin-1: gratitude: β=−.009, [−.017, −.001]; optimism: β=−.009, [−.016, −.001]; soluble intercellular adhesion molecule-1: gratitude: β=−.007, [−.014, −.000]), independent of depressive and anxiety symptoms. Psychological constructs at 2 weeks were not prospectively associated with biomarkers at 6 months. Conclusions Depressive symptoms were associated with more inflammation, myocardial strain, and endothelial dysfunction in the 6 months post-ACS, while positive psychological constructs were linked to better endothelial function. Larger, prospective studies may clarify the directionality of these relationships. PMID:27749683

Simulated versus observed patterns of warming over the extratropical Northern Hemisphere continents during the cold season

PubMed Central

Wallace, John M.; Fu, Qiang; Smoliak, Brian V.; Lin, Pu; Johanson, Celeste M.

2012-01-01

A suite of the historical simulations run with the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4) models forced by greenhouse gases, aerosols, stratospheric ozone depletion, and volcanic eruptions and a second suite of simulations forced by increasing CO2 concentrations alone are compared with observations for the reference interval 1965–2000. Surface air temperature trends are disaggregated by boreal cold (November-April) versus warm (May-October) seasons and by high latitude northern (N: 40°–90 °N) versus southern (S: 60 °S–40 °N) domains. A dynamical adjustment is applied to remove the component of the cold-season surface air temperature trends (over land areas poleward of 40 °N) that are attributable to changing atmospheric circulation patterns. The model simulations do not simulate the full extent of the wintertime warming over the high-latitude Northern Hemisphere continents during the later 20th century, much of which was dynamically induced. Expressed as fractions of the concurrent trend in global-mean sea surface temperature, the relative magnitude of the dynamically induced wintertime warming over domain N in the observations, the simulations with multiple forcings, and the runs forced by the buildup of greenhouse gases only is 7∶2∶1, and roughly comparable to the relative magnitude of the concurrent sea-level pressure trends. These results support the notion that the enhanced wintertime warming over high northern latitudes from 1965 to 2000 was mainly a reflection of unforced variability of the coupled climate system. Some of the simulations exhibit an enhancement of the warming along the Arctic coast, suggestive of exaggerated feedbacks. PMID:22847408

Inhibiting PKMζ reveals dorsal lateral and dorsal medial striatum store the different memories needed to support adaptive behavior.

PubMed

Pauli, Wolfgang M; Clark, Alexandra D; Guenther, Heidi J; O'Reilly, Randall C; Rudy, Jerry W

2012-06-20

Evidence suggests that two regions of the striatum contribute differential support to instrumental response selection. The dorsomedial striatum (DMS) is thought to support expectancy-mediated actions, and the dorsolateral striatum (DLS) is thought to support habits. Currently it is unclear whether these regions store task-relevant information or just coordinate the learning and retention of these solutions by other brain regions. To address this issue, we developed a two-lever concurrent variable-interval reinforcement operant conditioning task and used it to assess the trained rat's sensitivity to contingency shifts. Consistent with the view that these two regions make different contributions to actions and habits, injecting the NMDA antagonist DL-AP5 into the DMS just prior to the shift impaired the rat's performance but enhanced performance when injected into the DLS. To determine if these regions support memory content, we first trained rats on a biased concurrent schedule (Lever 1: VI 40" and Lever 2: VI 10"). With the intent of "erasing" the memory content stored in striatum, after this training we inhibited the putative memory-maintenance protein kinase C isozyme protein kinase Mζ (PKMζ). Infusing zeta inhibitory peptide (ZIP) into the DLS enhanced the rat's ability to adapt to the contingency shift 2 d later, whereas injecting it into the DMS had the opposite effect. Infusing GluR2(3Y) into the DMS 1 h before ZIP infusions prevented ZIP from impairing the rat's sensitivity to the contingency shift. These results support the hypothesis that the DMS stores information needed to support actions and the DLS stores information needed to support habits.

Generalized concurrence in boson sampling.

PubMed

Chin, Seungbeom; Huh, Joonsuk

2018-04-17

A fundamental question in linear optical quantum computing is to understand the origin of the quantum supremacy in the physical system. It is found that the multimode linear optical transition amplitudes are calculated through the permanents of transition operator matrices, which is a hard problem for classical simulations (boson sampling problem). We can understand this problem by considering a quantum measure that directly determines the runtime for computing the transition amplitudes. In this paper, we suggest a quantum measure named "Fock state concurrence sum" C S , which is the summation over all the members of "the generalized Fock state concurrence" (a measure analogous to the generalized concurrences of entanglement and coherence). By introducing generalized algorithms for computing the transition amplitudes of the Fock state boson sampling with an arbitrary number of photons per mode, we show that the minimal classical runtime for all the known algorithms directly depends on C S . Therefore, we can state that the Fock state concurrence sum C S behaves as a collective measure that controls the computational complexity of Fock state BS. We expect that our observation on the role of the Fock state concurrence in the generalized algorithm for permanents would provide a unified viewpoint to interpret the quantum computing power of linear optics.

Preliminary Results of Whole Brain Radiotherapy With Concurrent Trastuzumab for Treatment of Brain Metastases in Breast Cancer Patients

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chargari, Cyrus; Idrissi, Hind Riahi; Pierga, Jean-Yves

2011-11-01

Purpose: To assess the use of trastuzumab concurrently with whole brain radiotherapy (WBRT) for patients with brain metastases from human epidermal growth factor receptor-2-positive breast cancer. Methods and Materials: Between April 2001 and April 2007, 31 patients with brain metastases from human epidermal growth factor receptor-2-positive breast cancer were referred for WBRT with concurrent trastuzumab. At brain progression, the median age was 55 years (range, 38-73), and all patients had a performance status of 0-2. The patients received trastuzumab 2 mg/kg weekly (n = 17) or 6 mg/kg repeated every 21 days (n = 14). In 26 patients, concurrent WBRTmore » delivered 30 Gy in 10 daily fractions. In 6 patients, other fractionations were chosen because of either poor performance status or patient convenience. Results: After WBRT, radiologic responses were observed in 23 patients (74.2%), including 6 (19.4%) with a complete radiologic response and 17 (54.8%) with a partial radiologic response. Clinical responses were observed in 27 patients (87.1%). The median survival time from the start of WBRT was 18 months (range, 2-65). The median interval to brain progression was 10.5 months (range, 2-27). No Grade 2 or greater acute toxicity was observed. Conclusion: The low toxicity of trastuzumab concurrently with WBRT should probably not justify delays. Although promising, these preliminary data warrant additional validation of trastuzumab as a potential radiosensitizer for WBRT in brain metastases from breast cancer in the setting of a clinical trial.« less

Concurrent chemo-radiotherapy with S-1 as an alternative therapy for elderly Chinese patients with non-metastatic esophageal squamous cancer: evidence based on a systematic review and meta-analysis.

PubMed

Song, Guo-Min; Tian, Xu; Liu, Xiao-Ling; Chen, Hui; Zhou, Jian-Guo; Bian, Wei; Chen, Wei-Qing

2017-06-06

This systematic review and meta-analysis aims to systematically assess the effects of concurrent chemo-radiotherapy (CRT) compared with radiotherapy (RT) alone for elderly Chinese patients with non-metastatic esophageal squamous cancer. We searched PubMed, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), China Biomedical Literature Database (CBM), and China National Knowledge Infrastructure (CNKI) databases. We retrieved randomized controlled trials on concurrent CRT with Gimeraciland Oteracil Porassium (S-1) compared with RT alone for aged Chinese patients with non-metastatic esophageal squamous cancer performed until August 2016. Eight eligible studies involving 536 patients were subjected to meta-analysis. As a response rate measure, a relative risk (RR) of 1.37 [95% confidence intervals (CIs): 1.24, 1.53; P = 0.00], which reached statistical significance, was estimated when concurrent CRT with S-1 was performed compared with RT alone. Sensitivity analysis on response rate confirmed the robustness of the pooled result. The RR values of 1.44 (95% CIs: 1.22, 1.70; P = 0.00) and 1.77 (95% CIs: 1.26, 2.48; P = 0.00) estimated for 1- and 2-year survival rate indices, respectively, were also statistically significant. The incidence of adverse events was similar in both groups. This review concluded that concurrent CRT with S-1 can improve the efficacy and prolong the survival period of elderly Chinese patients with non-metastatic esophageal squamous cancer and does not significantly increase the acute adverse effects of RT alone.

The distribution of middle tropospheric carbon monoxide during early October 1984

NASA Technical Reports Server (NTRS)

Reichle, Henry G., Jr.; Connors, Vickie S.; Holland, J. Alvin; Sherrill, Robert T.; Wallio, H. Andrew; Casas, Joseph C.; Condon, Estelle P.

1990-01-01

The measurement of Air Pollution from Satellite experiment measured the distribution of middle-tropospheric CO from the Space Shuttle during October 1984. The data represent average mixing ratios between 57 deg N and 57 deg S. Approximately 75,000 individual CO measurements were obtained during the 9-day mission. The data are presented in maps that show the CO mixing ratios averaged over 5 x 5-deg areas for 6 days of the mission. Comparisons with concurrent direct measurements taken aboard aircraft show that the inferred concentrations are systematically low by 20-40 percent, depending upon which direct measurement calibration standard is used. The data show that there are very large CO sources resulting from biomass burning over South America and southern Africa. Measured mixing ratios were high over northeast Asia and were highly variable over Europe.

Integrated System-Level Optimization for Concurrent Engineering With Parametric Subsystem Modeling

NASA Technical Reports Server (NTRS)

Schuman, Todd; DeWeck, Oliver L.; Sobieski, Jaroslaw

2005-01-01

The introduction of concurrent design practices to the aerospace industry has greatly increased the productivity of engineers and teams during design sessions as demonstrated by JPL's Team X. Simultaneously, advances in computing power have given rise to a host of potent numerical optimization methods capable of solving complex multidisciplinary optimization problems containing hundreds of variables, constraints, and governing equations. Unfortunately, such methods are tedious to set up and require significant amounts of time and processor power to execute, thus making them unsuitable for rapid concurrent engineering use. This paper proposes a framework for Integration of System-Level Optimization with Concurrent Engineering (ISLOCE). It uses parametric neural-network approximations of the subsystem models. These approximations are then linked to a system-level optimizer that is capable of reaching a solution quickly due to the reduced complexity of the approximations. The integration structure is described in detail and applied to the multiobjective design of a simplified Space Shuttle external fuel tank model. Further, a comparison is made between the new framework and traditional concurrent engineering (without system optimization) through an experimental trial with two groups of engineers. Each method is evaluated in terms of optimizer accuracy, time to solution, and ease of use. The results suggest that system-level optimization, running as a background process during integrated concurrent engineering sessions, is potentially advantageous as long as it is judiciously implemented.

Correlation of arterial fetal base deficit and lactate changes with severity of variable heart rate decelerations in the near-term ovine fetus.

PubMed

Ross, Michael G; Jessie, Marquis; Amaya, Kevin; Matushewski, Brad; Durosier, L Daniel; Frasch, Martin G; Richardson, Bryan S

2013-04-01

Recent guidelines classify variable decelerations without detail as to degree of depth. We hypothesized that variable deceleration severity is highly correlated with fetal base deficit accumulation. Seven near-term fetal sheep underwent a series of graded umbilical cord occlusions resulting in mild (30 bpm decrease), moderate (60 bpm decrease), or severe (decrease of 90 bpm to baseline <70 bpm) variable decelerations at 2.5 minute intervals. Mild, moderate, and severe variable decelerations increased fetal base deficit (0.21 ± 0.03, 0.27 ± 0.03, and 0.54 ± 0.09 mEq/L per minute) in direct proportion to severity. During recovery, fetal base deficit cleared at 0.12 mEq/L per minute. In this model, ovine fetuses can tolerate repetitive mild and moderate variable decelerations with minimal change in base deficit and lactate. In contrast, repetitive severe variable decelerations may result in significant base deficit increases, dependent on frequency. Modified guideline differentiation of mild/moderate vs severe variable decelerations may aid in the interpretation of fetal heart rate tracings and optimization of clinical management paradigms. Copyright © 2013 Mosby, Inc. All rights reserved.

The effects of auditory stimulation with music on heart rate variability in healthy women.

PubMed

Roque, Adriano L; Valenti, Vitor E; Guida, Heraldo L; Campos, Mônica F; Knap, André; Vanderlei, Luiz Carlos M; Ferreira, Lucas L; Ferreira, Celso; Abreu, Luiz Carlos de

2013-07-01

There are no data in the literature with regard to the acute effects of different styles of music on the geometric indices of heart rate variability. In this study, we evaluated the acute effects of relaxant baroque and excitatory heavy metal music on the geometric indices of heart rate variability in women. We conducted this study in 21 healthy women ranging in age from 18 to 35 years. We excluded persons with previous experience with musical instruments and persons who had an affinity for the song styles. We evaluated two groups: Group 1 (n = 21), who were exposed to relaxant classical baroque musical and excitatory heavy metal auditory stimulation; and Group 2 (n = 19), who were exposed to both styles of music and white noise auditory stimulation. Using earphones, the volunteers were exposed to baroque or heavy metal music for five minutes. After the first music exposure to baroque or heavy metal music, they remained at rest for five minutes; subsequently, they were re-exposed to the opposite music (70-80 dB). A different group of women were exposed to the same music styles plus white noise auditory stimulation (90 dB). The sequence of the songs was randomized for each individual. We analyzed the following indices: triangular index, triangular interpolation of RR intervals and Poincaré plot (standard deviation of instantaneous beat-by-beat variability, standard deviation of the long-term RR interval, standard deviation of instantaneous beat-by-beat variability and standard deviation of the long-term RR interval ratio), low frequency, high frequency, low frequency/high frequency ratio, standard deviation of all the normal RR intervals, root-mean square of differences between the adjacent normal RR intervals and the percentage of adjacent RR intervals with a difference of duration greater than 50 ms. Heart rate variability was recorded at rest for 10 minutes. The triangular index and the standard deviation of the long-term RR interval indices were reduced during exposure to both music styles in the first group and tended to decrease in the second group whereas the white noise exposure decreased the high frequency index. We observed no changes regarding the triangular interpolation of RR intervals, standard deviation of instantaneous beat-by-beat variability and standard deviation of instantaneous beat-by-beat variability/standard deviation in the long-term RR interval ratio. We suggest that relaxant baroque and excitatory heavy metal music slightly decrease global heart rate variability because of the equivalent sound level.

The effects of auditory stimulation with music on heart rate variability in healthy women

PubMed Central

Roque, Adriano L.; Valenti, Vitor E.; Guida, Heraldo L.; Campos, Mônica F.; Knap, André; Vanderlei, Luiz Carlos M.; Ferreira, Lucas L.; Ferreira, Celso; de Abreu, Luiz Carlos

2013-01-01

OBJECTIVES: There are no data in the literature with regard to the acute effects of different styles of music on the geometric indices of heart rate variability. In this study, we evaluated the acute effects of relaxant baroque and excitatory heavy metal music on the geometric indices of heart rate variability in women. METHODS: We conducted this study in 21 healthy women ranging in age from 18 to 35 years. We excluded persons with previous experience with musical instruments and persons who had an affinity for the song styles. We evaluated two groups: Group 1 (n = 21), who were exposed to relaxant classical baroque musical and excitatory heavy metal auditory stimulation; and Group 2 (n = 19), who were exposed to both styles of music and white noise auditory stimulation. Using earphones, the volunteers were exposed to baroque or heavy metal music for five minutes. After the first music exposure to baroque or heavy metal music, they remained at rest for five minutes; subsequently, they were re-exposed to the opposite music (70-80 dB). A different group of women were exposed to the same music styles plus white noise auditory stimulation (90 dB). The sequence of the songs was randomized for each individual. We analyzed the following indices: triangular index, triangular interpolation of RR intervals and Poincaré plot (standard deviation of instantaneous beat-by-beat variability, standard deviation of the long-term RR interval, standard deviation of instantaneous beat-by-beat variability and standard deviation of the long-term RR interval ratio), low frequency, high frequency, low frequency/high frequency ratio, standard deviation of all the normal RR intervals, root-mean square of differences between the adjacent normal RR intervals and the percentage of adjacent RR intervals with a difference of duration greater than 50 ms. Heart rate variability was recorded at rest for 10 minutes. RESULTS: The triangular index and the standard deviation of the long-term RR interval indices were reduced during exposure to both music styles in the first group and tended to decrease in the second group whereas the white noise exposure decreased the high frequency index. We observed no changes regarding the triangular interpolation of RR intervals, standard deviation of instantaneous beat-by-beat variability and standard deviation of instantaneous beat-by-beat variability/standard deviation in the long-term RR interval ratio. CONCLUSION: We suggest that relaxant baroque and excitatory heavy metal music slightly decrease global heart rate variability because of the equivalent sound level. PMID:23917660

Traumatic Fractures of the Cervical Spine: Analysis of Changes in Incidence, Cause, Concurrent Injuries, and Complications Among 488,262 Patients from 2005 to 2013.

PubMed

Passias, Peter G; Poorman, Gregory W; Segreto, Frank A; Jalai, Cyrus M; Horn, Samantha R; Bortz, Cole A; Vasquez-Montes, Dennis; Diebo, Bassel G; Vira, Shaleen; Bono, Olivia J; De La Garza-Ramos, Rafael; Moon, John Y; Wang, Charles; Hirsch, Brandon P; Zhou, Peter L; Gerling, Michael; Koller, Heiko; Lafage, Virginie

2018-02-01

The causes and epidemiology of traumatic cervical spine fracture have not been described with sufficient power or recency. Our goal is to describe demographics, incidence, cause, spinal cord injuries (SCIs), concurrent injuries, treatments, and complications of traumatic cervical spine fractures. A retrospective review was carried out of the Nationwide Inpatient Sample. International Classification of Disease, Ninth Revision E-codes identified trauma cases from 2005 to 2013. Patients with cervical fracture were isolated. Demographics, incidence, cause, fracture levels, concurrent injuries, surgical procedures, and complications were analyzed. t tests elucidated significance for continuous variables and χ 2 for categorical variables. Level of significance was P < 0.05. A total of 488,262 patients were isolated (age, 55.96 years; male, 60.0%; white, 77.5%). Incidence (2005, 4.1% vs. 2013, 5.4%), Charlson Comorbidity Index (2005, 0.6150 vs. 2013, 1.1178), and total charges (2005, $71,228.60 vs. 2013, $108,119.29) have increased since 2005, whereas length of stay decreased (2005, 9.22 vs. 2013, 7.86) (all P < 0.05). The most common causes were motor vehicle accident (29.3%), falls (23.7%), and pedestrian accidents (15.7%). The most frequent fracture types were closed at C2 (32.0%) and C7 (20.9%). Concurrent injury rates have significantly increased since 2005 (2005, 62.3% vs. 2013, 67.6%). Common concurrent injuries included fractures to the rib/sternum/larynx/trachea (19.6%). Overall fusion rates have increased since 2005 (2005, 15.7% vs. 2013, 18.0%), whereas decompressions and halo insertion rates have decreased (all P < 0.05). SCIs have significantly decreased since 2005, except for upper cervical central cord syndrome. Complication rates have significantly increased since 2005 (2005, 31.6% vs. 2013, 36.2%). Common complications included anemia (7.7%), mortality (6.6%), and acute respiratory distress syndrome (6.6%). Incidence, complications, concurrent injuries, and fusions have increased since 2005. Length of stay, SCIs, decompressions, and halo insertions have decreased. Indicated trends should guide future research in management guidelines. Copyright © 2017 Elsevier Inc. All rights reserved.

Three-Dimensional Upward Flame Spreading in Partial-Gravity Buoyant Flows

NASA Technical Reports Server (NTRS)

Sacksteder, Kurt R.; Feier, Ioan I.; Shih, Hsin-Yi; T'ien, James S.

2001-01-01

Reduced-gravity environments have been used to establish low-speed, purely forced flows for both opposed- and concurrent-flow flame spread studies. Altenkirch's group obtained spacebased experimental results and developed unsteady, two-dimensional numerical simulations of opposed-flow flame spread including gas-phase radiation, primarily away from the flammability limit for thin fuels, but including observations of thick fuel quenching in quiescent environments. T'ien's group contributed some early flame spreading results for thin fuels both in opposed flow and concurrent flow regimes, with more focus on near-limit conditions. T'ien's group also developed two- and three-dimensional numerical simulations of concurrent-flow flame spread incorporating gas-phase radiative models, including predictions of a radiatively-induced quenching limit reached in very low-speed air flows. Radiative quenching has been subsequently observed in other studies of combustion in very low-speed flows including other flame spread investigations, droplet combustion and homogeneous diffusion flames, and is the subject of several contemporary studies reported in this workshop. Using NASA aircraft flying partial-gravity "parabolic" trajectories, flame spreading in purely buoyant, opposed-flow (downward burning) has been studied. These results indicated increases in flame spread rates and enhanced flammability (lower limiting atmospheric oxygen content) as gravity levels were reduced from normal Earth gravity, and were consistent with earlier data obtained by Altenkirch using a centrifuge. In this work, experimental results and a three-dimensional numerical simulation of upward flame spreading in variable partial-gravity environments were obtained including some effects of reduced pressure and variable sample width. The simulation provides physical insight for interpreting the experimental results and shows the intrinsic 3-D nature of buoyant, upward flame spreading. This study is intended to link the evolving understanding of flame spreading in purely-forced flows to the purely-buoyant flow environment, particularly in the concurrent flow regime; provide additional insight into the existence of steady flame spread in concurrent flows; and stimulate direct comparisons between opposed- and concurrent-flow flame spread. Additionally, this effort is intended to provide direct practical understanding applicable to fire protection planning for the habitable facilities in partial gravity environments of anticipated Lunar and Martian explorations.

Joint modelling rationale for chained equations

PubMed Central

2014-01-01

Background Chained equations imputation is widely used in medical research. It uses a set of conditional models, so is more flexible than joint modelling imputation for the imputation of different types of variables (e.g. binary, ordinal or unordered categorical). However, chained equations imputation does not correspond to drawing from a joint distribution when the conditional models are incompatible. Concurrently with our work, other authors have shown the equivalence of the two imputation methods in finite samples. Methods Taking a different approach, we prove, in finite samples, sufficient conditions for chained equations and joint modelling to yield imputations from the same predictive distribution. Further, we apply this proof in four specific cases and conduct a simulation study which explores the consequences when the conditional models are compatible but the conditions otherwise are not satisfied. Results We provide an additional “non-informative margins” condition which, together with compatibility, is sufficient. We show that the non-informative margins condition is not satisfied, despite compatible conditional models, in a situation as simple as two continuous variables and one binary variable. Our simulation study demonstrates that as a consequence of this violation order effects can occur; that is, systematic differences depending upon the ordering of the variables in the chained equations algorithm. However, the order effects appear to be small, especially when associations between variables are weak. Conclusions Since chained equations is typically used in medical research for datasets with different types of variables, researchers must be aware that order effects are likely to be ubiquitous, but our results suggest they may be small enough to be negligible. PMID:24559129

Automatic and Robust Delineation of the Fiducial Points of the Seismocardiogram Signal for Non-invasive Estimation of Cardiac Time Intervals.

PubMed

Khosrow-Khavar, Farzad; Tavakolian, Kouhyar; Blaber, Andrew; Menon, Carlo

2016-10-12

The purpose of this research was to design a delineation algorithm that could detect specific fiducial points of the seismocardiogram (SCG) signal with or without using the electrocardiogram (ECG) R-wave as the reference point. The detected fiducial points were used to estimate cardiac time intervals. Due to complexity and sensitivity of the SCG signal, the algorithm was designed to robustly discard the low-quality cardiac cycles, which are the ones that contain unrecognizable fiducial points. The algorithm was trained on a dataset containing 48,318 manually annotated cardiac cycles. It was then applied to three test datasets: 65 young healthy individuals (dataset 1), 15 individuals above 44 years old (dataset 2), and 25 patients with previous heart conditions (dataset 3). The algorithm accomplished high prediction accuracy with the rootmean- square-error of less than 5 ms for all the test datasets. The algorithm overall mean detection rate per individual recordings (DRI) were 74, 68, and 42 percent for the three test datasets when concurrent ECG and SCG were used. For the standalone SCG case, the mean DRI was 32, 14 and 21 percent. When the proposed algorithm applied to concurrent ECG and SCG signals, the desired fiducial points of the SCG signal were successfully estimated with a high detection rate. For the standalone case, however, the algorithm achieved high prediction accuracy and detection rate for only the young individual dataset. The presented algorithm could be used for accurate and non-invasive estimation of cardiac time intervals.

Variability of Decimetre and Centimetre Scale Ice Surface Roughness and the Potential Consequences on the CryoSat Radar Altimeter Signal

NASA Astrophysics Data System (ADS)

Cawkwell, F. G.; Burgess, D. O.; Sharp, M. J.; Demuth, M.

2004-12-01

Snow and ice surface roughness affect the backscatter of the pulse emitted by a radar altimeter, and hence the accuracy of the surface elevation calculated from the waveform echo, but the influence of surface roughness has not been quantified. As part of the CryoSat calibration/validation field campaigns on the Devon Ice Cap in 2004, surface roughness measurements were made at 0.1-7km intervals along a 48km transect from near the summit to the southern margin. Measurements were made at the decimetre scale by surveying and at the centimetre scale using digital photography. The data collected were subjected to wavelet analysis to define characteristic roughness wavelengths, and the fractal dimension associated with each of these was calculated using the semi-variogram method. Vario functions were calculated for the photographic data. The survey results show that wavelength scales depend on orientation and distance from the ice cap summit, the fractal dimension depends on the wavelength scale and the orientation, and both are significantly affected by storm events. Profiles aligned with the easterly prevailing wind direction, and thus perpendicular to the predicted satellite track, proved to be more sensitive to meteorological events than those normal to the dominant winds. Wavelet and fractal analysis of the photographic data was less conclusive, potentially due to the `noisier' nature of the data at this scale, where `noise' is actually the superimposition of small scale wavelengths onto larger ones. Vario analysis showed the characteristic wavelengths at the centimetre scale to increase with distance from the summit, although the abrading effect of storm events caused a decrease in wavelength. The amplitude of the roughness also increases with distance from the summit, although following a period of calm this value is significantly decreased along the transect. Orientation with respect to the prevailing wind direction is also a significant factor. Analysis of the return waveforms acquired by an airborne radar altimeter concurrently with ground data will allow the impact of the different roughness scales and orientations to be assessed.

Do religion and religiosity have anything to do with alcohol consumption patterns? Evidence from two fish landing sites on Lake Victoria Uganda.

PubMed

Tumwesigye, Nazarius M; Atuyambe, Lynn; Kibira, Simon P S; Wabwire-Mangen, Fred; Tushemerirwe, Florence; Wagner, Glenn J

2013-09-01

Fish landing sites have high levels of harmful use of alcohol. This paper examines the role of religion and religiosity on alcohol consumption at two fish landing sites on Lake Victoria in Uganda. Questionnaires were administered to randomly selected people at the sites. Dependent variables included alcohol consumption during the previous 30 days, whereas the key independent variables were religion and religiosity. Bivariate and multivariate analysis techniques were applied. People reporting low religiosity were five times more likely to have consumed alcohol (95% confidence interval: 2.45-10.04) compared with those reporting low/average religiosity. Religion and religiosity are potential channels for controlling alcohol use.

Low temperature resistivity studies of SmB6: Observation of two-dimensional variable-range hopping conductivity

NASA Astrophysics Data System (ADS)

Batkova, Marianna; Batko, Ivan; Gabáni, Slavomír; Gažo, Emil; Konovalova, Elena; Filippov, Vladimir

2018-05-01

We studied electrical resistance of a single-crystalline SmB6 sample with a focus on the region of the "low-temperature resistivity plateau". Our observations did not show any true saturation of the electrical resistance at temperatures below 3 K down to 70 mK. According to our findings, temperature dependence of the electrical conduction in a certain temperature interval above 70 mK can be decomposed into a temperature-independent term and a temperature-activated term that can be described by variable-range hopping formula for two-dimensional systems, exp [ -(T0 / T) 1 / 3 ]. Thus, our results indicate importance of hopping type of electrical transport in the near-surface region of SmB6.

Verification of the effects of Schumann frequency range electromagnetic fields on the human cardiovascular system

NASA Astrophysics Data System (ADS)

Tuzhilkin, D. A.; Borodin, A. S.

2017-11-01

The results of the study of variations in the electromagnetic background parameters of the Schumann resonator frequency range and the variability indices of the human heart period during its free activity are presented on the basis of 24-hour synchronous monitoring data. It is shown that the integral evaluation of the conjugacy of the heart rate variability indices from the Schumann resonance parameters is extremely weak. In this case, the differential evaluation of this dependence with separation into characteristic time intervals of the day, characterized by different motor activity of the subjects, becomes significantly higher. The number of volunteers whose conjugacy is characterized by a strong correlation in some cases reaches 35 percent of the sample.

Differential effects of smoking on lung cancer mortality before and after household stove improvement in Xuanwei, China.

PubMed

Lee, K-M; Chapman, R S; Shen, M; Lubin, J H; Silverman, D T; He, X; Hosgood, H D; Chen, B E; Rajaraman, P; Caporaso, N E; Fraumeni, J F; Blair, A; Lan, Q

2010-08-24

In Xuanwei County, Yunnan Province, China, lung cancer mortality rates in both males and females are among the highest in China. We evaluated differential effects of smoking on lung cancer mortality before and after household stove improvement with chimney to reduce exposure to smoky coal emissions in the unique cohort in Xuanwei, China. Effects of independent variables on lung cancer mortality were measured as hazard ratios and 95% confidence intervals using a multivariable Cox regression model that included separate time-dependent variables for smoking duration (years) before and after stove improvement. We found that the effect of smoking on lung cancer risk becomes considerably stronger after chimney installation and consequent reduction of indoor coal smoke exposure.

Food insecurity and CD4% Among HIV+ children in Gaborone, Botswana.

PubMed

Mendoza, Jason A; Matshaba, Mogomotsi; Makhanda, Jeremiah; Liu, Yan; Boitshwarelo, Matshwenyego; Anabwani, Gabriel M

2014-08-01

We investigated the association between household food insecurity (HFI) and CD4% among 2-6-year old HIV+ outpatients (n = 78) at the Botswana-Baylor Children's Clinical Center of Excellence in Gaborone, Botswana. HFI was assessed by a validated survey. CD4% data were abstracted from the medical record. We used multiple linear regression with CD4% (dependent variable), HFI (independent variable), and controlled for sociodemographic and clinical covariates. Multiple linear regression showed a significant main effect for HFI [beta = -0.6, 95% confidence interval (CI): -1.0 to -0.1] and child gender (beta = 5.6, 95% CI: 1.3 to 9.8). Alleviating food insecurity may improve pediatric HIV outcomes in Botswana and similar Sub-Saharan settings.

Performing concurrent operations in academic vascular neurosurgery does not affect patient outcomes.

PubMed

Zygourakis, Corinna C; Lee, Janelle; Barba, Julio; Lobo, Errol; Lawton, Michael T

2017-11-01

OBJECTIVE Concurrent surgeries, also known as "running two rooms" or simultaneous/overlapping operations, have recently come under intense scrutiny. The goal of this study was to evaluate the operative time and outcomes of concurrent versus nonconcurrent vascular neurosurgical procedures. METHODS The authors retrospectively reviewed 1219 procedures performed by 1 vascular neurosurgeon from 2012 to 2015 at the University of California, San Francisco. Data were collected on patient age, sex, severity of illness, risk of mortality, American Society of Anesthesiologists (ASA) status, procedure type, admission type, insurance, transfer source, procedure time, presence of resident or fellow in operating room (OR), number of co-surgeons, estimated blood loss (EBL), concurrent vs nonconcurrent case, severe sepsis, acute respiratory failure, postoperative stroke causing neurological deficit, unplanned return to OR, 30-day mortality, and 30-day unplanned readmission. For aneurysm clipping cases, data were also obtained on intraoperative aneurysm rupture and postoperative residual aneurysm. Chi-square and t-tests were performed to compare concurrent versus nonconcurrent cases, and then mixed-effects models were created to adjust for different procedure types, patient demographics, and clinical indicators between the 2 groups. RESULTS There was a significant difference in procedure type for concurrent (n = 828) versus nonconcurrent (n = 391) cases. Concurrent cases were more likely to be routine/elective admissions (53% vs 35%, p < 0.001) and physician referrals (59% vs 38%, p < 0.001). This difference in patient/case type was also reflected in the lower severity of illness, risk of death, and ASA class in the concurrent versus nonconcurrent cases (p < 0.01). Concurrent cases had significantly longer procedural times (243 vs 213 minutes) and more unplanned 30-day readmissions (5.7% vs 3.1%), but shorter mean length of hospital stay (11.2 vs 13.7 days), higher rates of discharge to home (66% vs 51%), lower 30-day mortality rates (3.1% vs 6.1%), lower rates of acute respiratory failure (4.3% vs 8.2%), and decreased 30-day unplanned returns to the OR (3.3% vs 6.9%; all p < 0.05). Rates of severe sepsis, postoperative stroke, intraoperative aneurysm rupture, and postoperative aneurysm residual were equivalent between the concurrent and nonconcurrent groups (all p values nonsignificant). Mixed-effects models showed that after controlling for procedure type, patient demographics, and clinical indicators, there was no significant difference in acute respiratory failure, severe sepsis, 30-day readmission, postoperative stroke, EBL, length of stay, discharge status, or intraoperative aneurysm rupture between concurrent and nonconcurrent cases. Unplanned return to the OR and 30-day mortality were significantly lower in concurrent cases (odds ratio 0.55, 95% confidence interval 0.31-0.98, p = 0.0431, and odds ratio 0.81, p < 0.001, respectively), but concurrent cases had significantly longer procedure durations (odds ratio 21.73; p < 0.001). CONCLUSIONS Overall, there was a significant difference in the types of concurrent versus nonconcurrent cases, with more routine/elective cases for less sick patients scheduled in an overlapping fashion. After adjusting for patient demographics, procedure type, and clinical indicators, concurrent cases had longer procedure times, but equivalent patient outcomes, as compared with nonconcurrent vascular neurosurgical procedures.

Concurrent deep-superficial dyspareunia: prevalence, associations, and outcomes in a multidisciplinary vulvodynia program.

PubMed

Yong, Paul J; Sadownik, Leslie; Brotto, Lori A

2015-01-01

Little is known about women with concurrent diagnoses of deep dyspareunia and superficial dyspareunia. The aim of this study was to determine the prevalence, associations, and outcome of women with concurrent deep-superficial dyspareunia. This is a prospective study of a multidisciplinary vulvodynia program (n = 150; mean age 28.7 ± 6.4 years). Women with superficial dyspareunia due to provoked vestibulodynia were divided into two groups: those also having deep dyspareunia (i.e., concurrent deep-superficial dyspareunia) and those with only superficial dyspareunia due to provoked vestibulodynia. Demographics, dyspareunia-related factors, other pain conditions, and psychological variables at pretreatment were tested for an association with concurrent deep-superficial dyspareunia. Outcome in both groups was assessed to 6 months posttreatment. Level of dyspareunia pain (0-10) and Female Sexual Distress Scale were the main outcome measures. The prevalence of concurrent deep-superficial dyspareunia was 44% (66/150) among women with superficial dyspareunia due to provoked vestibulodynia. At pretreatment, on multiple logistic regression, concurrent deep-superficial dyspareunia was independently associated with a higher level of dyspareunia pain (odds ratio [OR] = 1.19 [1.01-1.39], P = 0.030), diagnosis of endometriosis (OR = 4.30 [1.16-15.90], P = 0.022), history of bladder problems (OR = 3.84 [1.37-10.76], P = 0.008), and more depression symptoms (OR = 1.07 [1.02-1.12], P = 0.007), with no difference in the Female Sexual Distress Scale. At 6 months posttreatment, women with concurrent deep-superficial dyspareunia improved in the level of dyspareunia pain and in the Female Sexual Distress Scale to the same degree as women with only superficial dyspareunia due to provoked vestibulodynia. Concurrent deep-superficial dyspareunia is reported by almost half of women in a multidisciplinary vulvodynia program. In women with provoked vestibulodynia, concurrent deep-superficial dyspareunia may be related to endometriosis or interstitial cystitis, and is associated with depression and more severe dyspareunia symptoms. Standardized multidisciplinary care is effective for women with concurrent dyspareunia. © 2014 International Society for Sexual Medicine.

Fractal correlation properties of R-R interval dynamics and mortality in patients with depressed left ventricular function after an acute myocardial infarction

NASA Technical Reports Server (NTRS)

Huikuri, H. V.; Makikallio, T. H.; Peng, C. K.; Goldberger, A. L.; Hintze, U.; Moller, M.

2000-01-01

BACKGROUND: Preliminary data suggest that the analysis of R-R interval variability by fractal analysis methods may provide clinically useful information on patients with heart failure. The purpose of this study was to compare the prognostic power of new fractal and traditional measures of R-R interval variability as predictors of death after acute myocardial infarction. METHODS AND RESULTS: Time and frequency domain heart rate (HR) variability measures, along with short- and long-term correlation (fractal) properties of R-R intervals (exponents alpha(1) and alpha(2)) and power-law scaling of the power spectra (exponent beta), were assessed from 24-hour Holter recordings in 446 survivors of acute myocardial infarction with a depressed left ventricular function (ejection fraction

Multi-hazard Assessment and Scenario Toolbox (MhAST): A Framework for Analyzing Compounding Effects of Multiple Hazards

NASA Astrophysics Data System (ADS)

Sadegh, M.; Moftakhari, H.; AghaKouchak, A.

2017-12-01

Many natural hazards are driven by multiple forcing variables, and concurrence/consecutive extreme events significantly increases risk of infrastructure/system failure. It is a common practice to use univariate analysis based upon a perceived ruling driver to estimate design quantiles and/or return periods of extreme events. A multivariate analysis, however, permits modeling simultaneous occurrence of multiple forcing variables. In this presentation, we introduce the Multi-hazard Assessment and Scenario Toolbox (MhAST) that comprehensively analyzes marginal and joint probability distributions of natural hazards. MhAST also offers a wide range of scenarios of return period and design levels and their likelihoods. Contribution of this study is four-fold: 1. comprehensive analysis of marginal and joint probability of multiple drivers through 17 continuous distributions and 26 copulas, 2. multiple scenario analysis of concurrent extremes based upon the most likely joint occurrence, one ruling variable, and weighted random sampling of joint occurrences with similar exceedance probabilities, 3. weighted average scenario analysis based on a expected event, and 4. uncertainty analysis of the most likely joint occurrence scenario using a Bayesian framework.

Five-Year Mortality After Transient Ischemic Attack: Focus on Cardiometabolic Comorbidity and Hospital Readmission.

PubMed

Yousufuddin, Mohammed; Young, Nathan; Keenan, Lawrence; Olson, Tammy; Shultz, Jessica; Doyle, Taylor; Ahmmad, Eimad M; Arumaithurai, Kogulavadanan; Takahashi, Paul; Murad, Mohammad Hassan

2018-03-01

We aimed at providing estimates of mortality associated with cardiometabolic comorbidity and incident readmission from cardiometabolic as compared with noncardiometabolic conditions after a first transient ischemic attack. Between 2000 and 2015, patients hospitalized for a first transient ischemic attack were examined for cardiometabolic comorbidities (diabetes mellitus, coronary artery disease, heart failure, and atrial fibrillation), 5-year incident hospitalization, and time to death. Of 251 patients with transient ischemic attack, 134 (53%) had at least 1 and 55 (22%) had at least 2 cardiometabolic conditions. By 5 years, 491 readmissions (134 [27%] cardiometabolic and 357 [73%] noncardiometabolic) and 75 deaths (27 [36%] cardiometabolic and 47 [64%] noncardiometabolic) were observed. Mortality was increased with any concurrent cardiometabolic comorbidity (hazard ratio, 1.89; 95% confidence interval, 1.17-3.03; P =0.0089) with multiplicative mortality risk from a combination of coronary artery disease and heart failure. Each hospitalization was associated with a 1.5-fold risk of death (95% confidence interval, 1.37-1.64; P <0.0001). Risk of cardiometabolic and noncardiometabolic mortality was correlated with the corresponding category-specific readmission. Among patients hospitalized for first transient ischemic attack, 5-year mortality is associated with concurrent cardiometabolic comorbidity and rates of subsequent hospitalization. © 2018 American Heart Association, Inc.

Cybernetics and Workshop Design.

ERIC Educational Resources Information Center

Eckstein, Daniel G.

1979-01-01

Cybernetic sessions allow for the investigation of several variables concurrently, resulting in a large volume of input compacted into a concise time frame. Three session questions are reproduced to illustrate the variety of ideas generated relative to workshop design. (Author)

Online evolution reconstruction from a single measurement record with random time intervals for quantum communication

NASA Astrophysics Data System (ADS)

Zhou, Hua; Su, Yang; Wang, Rong; Zhu, Yong; Shen, Huiping; Pu, Tao; Wu, Chuanxin; Zhao, Jiyong; Zhang, Baofu; Xu, Zhiyong

2017-10-01

Online reconstruction of a time-variant quantum state from the encoding/decoding results of quantum communication is addressed by developing a method of evolution reconstruction from a single measurement record with random time intervals. A time-variant two-dimensional state is reconstructed on the basis of recovering its expectation value functions of three nonorthogonal projectors from a random single measurement record, which is composed from the discarded qubits of the six-state protocol. The simulated results prove that our method is robust to typical metro quantum channels. Our work extends the Fourier-based method of evolution reconstruction from the version for a regular single measurement record with equal time intervals to a unified one, which can be applied to arbitrary single measurement records. The proposed protocol of evolution reconstruction runs concurrently with the one of quantum communication, which can facilitate the online quantum tomography.

"Straight Talk" for African-American heterosexual men: results of a single-arm behavioral intervention trial.

PubMed

Frye, Victoria; Henny, Kirk; Bonner, Sebastian; Williams, Kim; Bond, Keosha T; Hoover, Donald R; Lucy, Debbie; Greene, Emily; Koblin, Beryl A

2013-01-01

In the United States, heterosexual transmission is the second leading cause of HIV/AIDS, and two-thirds of all heterosexually acquired cases diagnosed between 2005 and 2008 occurred among African-Americans. Few HIV prevention interventions have been designed specifically for African-American heterosexual men not seeking clinical treatment. Here we report results of a single-arm intervention trial of a theory-based HIV prevention intervention designed to increase condom use, reduce concurrent partnering and increase HIV testing among heterosexually active African-American men living in high HIV prevalence areas of New York City. We tested our hypothesis using McNemar discordant pairs exact test for binary variables and paired t-tests for continuous variables. We observed statistically significant declines in mean number of total and new female partners, unprotected sex partners, and partner concurrency in both primary and nonprimary sex partnerships between baseline and 3 months postintervention.

Probabilistic properties of the Curve Number

NASA Astrophysics Data System (ADS)

Rutkowska, Agnieszka; Banasik, Kazimierz; Kohnova, Silvia; Karabova, Beata

2013-04-01

The determination of the Curve Number (CN) is fundamental for the hydrological rainfall-runoff SCS-CN method which assesses the runoff volume in small catchments. The CN depends on geomorphologic and physiographic properties of the catchment and traditionally it is assumed to be constant for each catchment. Many practitioners and researchers observe, however, that the parameter is characterized by a variability. This sometimes causes inconsistency in the river discharge prediction using the SCS-CN model. Hence probabilistic and statistical methods are advisable to investigate the CN as a random variable and to complement and improve the deterministic model. The results that will be presented contain determination of the probabilistic properties of the CNs for various Slovakian and Polish catchments using statistical methods. The detailed study concerns the description of empirical distributions (characteristics, QQ-plots and coefficients of goodness of fit, histograms), testing of the statistical hypotheses about some theoretical distributions (Kolmogorov-Smirnow, Anderson-Darling, Cramer-von Mises, χ2, Shapiro-Wilk), construction of confidence intervals and comparisons among catchments. The relationship between confidence intervals and the ARC soil classification will also be performed. The comparison between the border values of the confidence intervals and the ARC I and ARC III conditions is crucial for further modeling. The study of the response of the catchment to the stormy rainfall depth when the variability of the CN arises is also of special interest. ACKNOWLEDGMENTS The investigation described in the contribution has been initiated by first Author research visit to Technical University of Bratislava in 2012 within a STSM of the COST Action ES0901. Data used here have been provided by research project no. N N305 396238 founded by PL-Ministry of Science and Higher Education. The support provided by the organizations is gratefully acknowledged.

Bottom water production variability in the Ross Sea slope during the Late Pleistocene-Holocene as revealed by benthic foraminifera and sediment geochemistry

NASA Astrophysics Data System (ADS)

Langone, Leonardo; Asioli, Alessandra; Tateo, Fabio; Giglio, Federico; Ridente, Domenico; Summa, Vito; Carraro, Anna; Luigia Giannossi, Maria; Piva, Andrea; Trincardi, Fabio

2010-05-01

The Antarctic area produces bottom waters that ventilate the vast majority of the deep basins in the rest of the world ocean. The rate of formation in the source area and the strength of these cold bottom waters are key factors affecting the Global Thermohaline Circulation during modern and past climate conditions. The western Ross Sea is considered a formation site for a particularly salty variety of AABW as well as an important area of off-shelf transfer of water as plumes entraining in Lower CDW and as rapid downhill cascades. The results here presented were obtained within the frame of the PNRA project 4.8. Among the goals of the project, the main is to detect a qualitative signal of possible changes in the rate of bottom water production during the Late Pleistocene-Holocene by integrating data on foraminifera assemblages with sediment geochemistry (bulk mineralogy, Total Organic Carbon, biogenic silica, C and N stable isotopes) and IRD. A gravity core was collected at 2377m water depth off Drygalski Basin on the slope adjacent the western continental shelf of the Ross Sea, along the pathway of bottom water spreading. The chronology is based on the best fitting of twelve control points selected among twenty-two 14C AMS datings performed on the bulk organic carbon and 210Pb excess data. The trend of the parameters allows the following observations: 1) two main intervals (15-10 and 7.5-6 cab kyr BP) mark a subsequent enhanced nutrient supply. Indeed, δ15N variations depend on the utilization degree of nitrates, in turn reflecting productivity/nutrient supply changes. The concurrent increase of OC and biogenic silica suggests an increase of the nutrient availability. As the Upper CDW is a water mass rich in nutrients we interpret these intervals as characterized by a higher efficiency in the Upper CDW upwelling; 2) around 7.5-7kyr BP (part of the Middle Holocene Climatic Optimum) the IRD content drops, suggesting the reduction of iceberg production or a change of the iceberg path. Within this general context, an oscillatory trend is present from 15 kyr BP to present time. Two hypotheses are proposed: a) minima in foraminifera concentrations reflect relatively stronger dissolution, weaker bottom currents (minima in dry density) and lower nutrient supply (lighter values of δ15N). These intervals may reflect a lower rate of bottom water formation; the intervals corresponding to maxima in foraminifers concentration should indicate better preservation, higher benthic productivity and/or better oxygenation at bottom, stronger bottom currents (maxima in dry density) and relatively higher nutrient supply reflecting a relatively higher rate of bottom water formation. b) alternatively, minima in foraminifers, corresponding to minima in %OC and to reversal of 14C (relative increase of older carbon), reflect dilution in the sediment because of rapid accumulation of fine sediment re-suspended at the shelf edge by the cascading currents. Therefore, the minima represent higher rate of bottom water formation. The comparison of the D/H ratio in ice-cores from the Ross Sea sector with the core AS05-10 record indicates that the foraminifers minima always correspond to colder condition. This scenario also correlates to the record reported in literature on the slope off Wilkes-Adelie Land. At last, a condensed/hiatus interval at ca. 3.5-4 kyr BP does not seems to mark a major change in the general pattern of our variables, apart from biogenic silica and sheets silicates showing an increase of the oscillation amplitude. Nevertheless, this feature is coeval to the base of the Neoglacial and it is time-equivalent to the beginning of major changes in the Antarctic environment.

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

ERIC Educational Resources Information Center

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

2005-01-01

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

Retrospective Cost Adaptive Control with Concurrent Closed-Loop Identification

NASA Astrophysics Data System (ADS)

Sobolic, Frantisek M.

Retrospective cost adaptive control (RCAC) is a discrete-time direct adaptive control algorithm for stabilization, command following, and disturbance rejection. RCAC is known to work on systems given minimal modeling information which is the leading numerator coefficient and any nonminimum-phase (NMP) zeros of the plant transfer function. This information is normally needed a priori and is key in the development of the filter, also known as the target model, within the retrospective performance variable. A novel approach to alleviate the need for prior modeling of both the leading coefficient of the plant transfer function as well as any NMP zeros is developed. The extension to the RCAC algorithm is the use of concurrent optimization of both the target model and the controller coefficients. Concurrent optimization of the target model and controller coefficients is a quadratic optimization problem in the target model and controller coefficients separately. However, this optimization problem is not convex as a joint function of both variables, and therefore nonconvex optimization methods are needed. Finally, insights within RCAC that include intercalated injection between the controller numerator and the denominator, unveil the workings of RCAC fitting a specific closed-loop transfer function to the target model. We exploit this interpretation by investigating several closed-loop identification architectures in order to extract this information for use in the target model.

A cross-lagged structural equation model of relational aggression, physical aggression, and peer status in a Chinese culture.

PubMed

Tseng, Wan-Ling; Banny, Adrienne M; Kawabata, Yoshito; Crick, Nicki R; Gau, Susan Shur-Fen

2013-01-01

This short-term longitudinal study examined the associations among relational aggression, physical aggression, and peer status (i.e., acceptance, rejection, and perceived popularity) across three time points, six months apart, in a Taiwanese sample. Participants were 198 fifth grade students (94 girls and 104 boys; Mean age = 10.35 years) from Taipei, Taiwan. Study variables were assessed using peer nomination procedure. Results from the cross-lagged structural equation models demonstrated that there were longitudinal associations between relational aggression and each of the peer status constructs while only one longitudinal association was found for physical aggression such that physical aggression positively predicted subsequent peer rejection. The longitudinal associations did not vary with gender. Results also showed high stabilities of relational aggression, physical aggression, and the three peer status constructs over 1 year as well as high concurrent association between relational and physical aggression. In addition, relational aggression and physical aggression were concurrently related to less acceptance, more rejection, and less perceived popularity, especially at the outset of the study. Findings of this study demonstrated both similarities and differences in relation to previous literature in primarily Western cultures. This study also highlights the bidirectional and complex nature of the association between aggression and peer status, which appears to depend on the form of aggression and on the particular indicator of peer status under study. Copyright © 2013 Wiley Periodicals, Inc.

A New Approach for Determining Phase Response Curves Reveals that Purkinje Cells Can Act as Perfect Integrators

PubMed Central

Roth, Arnd; Häusser, Michael

2010-01-01

Cerebellar Purkinje cells display complex intrinsic dynamics. They fire spontaneously, exhibit bistability, and via mutual network interactions are involved in the generation of high frequency oscillations and travelling waves of activity. To probe the dynamical properties of Purkinje cells we measured their phase response curves (PRCs). PRCs quantify the change in spike phase caused by a stimulus as a function of its temporal position within the interspike interval, and are widely used to predict neuronal responses to more complex stimulus patterns. Significant variability in the interspike interval during spontaneous firing can lead to PRCs with a low signal-to-noise ratio, requiring averaging over thousands of trials. We show using electrophysiological experiments and simulations that the PRC calculated in the traditional way by sampling the interspike interval with brief current pulses is biased. We introduce a corrected approach for calculating PRCs which eliminates this bias. Using our new approach, we show that Purkinje cell PRCs change qualitatively depending on the firing frequency of the cell. At high firing rates, Purkinje cells exhibit single-peaked, or monophasic PRCs. Surprisingly, at low firing rates, Purkinje cell PRCs are largely independent of phase, resembling PRCs of ideal non-leaky integrate-and-fire neurons. These results indicate that Purkinje cells can act as perfect integrators at low firing rates, and that the integration mode of Purkinje cells depends on their firing rate. PMID:20442875

A consistent framework for Horton regression statistics that leads to a modified Hack's law

USGS Publications Warehouse

Furey, P.R.; Troutman, B.M.

2008-01-01

A statistical framework is introduced that resolves important problems with the interpretation and use of traditional Horton regression statistics. The framework is based on a univariate regression model that leads to an alternative expression for Horton ratio, connects Horton regression statistics to distributional simple scaling, and improves the accuracy in estimating Horton plot parameters. The model is used to examine data for drainage area A and mainstream length L from two groups of basins located in different physiographic settings. Results show that confidence intervals for the Horton plot regression statistics are quite wide. Nonetheless, an analysis of covariance shows that regression intercepts, but not regression slopes, can be used to distinguish between basin groups. The univariate model is generalized to include n > 1 dependent variables. For the case where the dependent variables represent ln A and ln L, the generalized model performs somewhat better at distinguishing between basin groups than two separate univariate models. The generalized model leads to a modification of Hack's law where L depends on both A and Strahler order ??. Data show that ?? plays a statistically significant role in the modified Hack's law expression. ?? 2008 Elsevier B.V.

The Influence of Recurrent Modes of Climate Variability on the Occurrence of Monthly Temperature Extremes Over South America

NASA Astrophysics Data System (ADS)

Loikith, Paul C.; Detzer, Judah; Mechoso, Carlos R.; Lee, Huikyo; Barkhordarian, Armineh

2017-10-01

The associations between extreme temperature months and four prominent modes of recurrent climate variability are examined over South America. Associations are computed as the percent of extreme temperature months concurrent with the upper and lower quartiles of the El Niño-Southern Oscillation (ENSO), the Atlantic Niño, the Pacific Decadal Oscillation (PDO), and the Southern Annular Mode (SAM) index distributions, stratified by season. The relationship is strongest for ENSO, with nearly every extreme temperature month concurrent with the upper or lower quartiles of its distribution in portions of northwestern South America during some seasons. The likelihood of extreme warm temperatures is enhanced over parts of northern South America when the Atlantic Niño index is in the upper quartile, while cold extremes are often association with the lowest quartile. Concurrent precipitation anomalies may contribute to these relations. The PDO shows weak associations during December, January, and February, while in June, July, and August its relationship with extreme warm temperatures closely matches that of ENSO. This may be due to the positive relationship between the PDO and ENSO, rather than the PDO acting as an independent physical mechanism. Over Patagonia, the SAM is highly influential during spring and fall, with warm and cold extremes being associated with positive and negative phases of the SAM, respectively. Composites of sea level pressure anomalies for extreme temperature months over Patagonia suggest an important role of local synoptic scale weather variability in addition to a favorable SAM for the occurrence of these extremes.

The Unusual Wolf-Rayet Star EZ CMa

NASA Technical Reports Server (NTRS)

Skinner, Stephen L.

2002-01-01

The XMM-Newton observations were obtained on 29 - 30 October 2001 during the AO-1 Guest Observer program. Our X-ray analysis focused on data from the European Photon Imaging Camera (EPIC). The VLA observations were obtained during a 3.5 hour interval on 1999 Oct. 19 with the array in hybrid BnA configuration. Radio continuum data were acquired at five different frequencies 1.42 GHz (21 cm), 4.86 GHz (6 cm), 8.44 GHz (3.6 cm), 14.94 GHz (2 cm), and 22.46 GHz (1.3 cm). These radio data are unique since they provide an excellent snapshot picture of the dependence of the radio flux on frequency obtained over a short time interval and are thus immune to the variability effects which can distort results obtained from non-contemporaneous observations at different frequencies.

The Effect of High-Intensity Interval Cycling Sprints Subsequent to Arm-Curl Exercise on Upper-Body Muscle Strength and Hypertrophy.

PubMed

Kikuchi, Naoki; Yoshida, Shou; Okuyama, Mizuki; Nakazato, Koichi

2016-08-01

Kikuchi, N, Yoshida, S, Okuyama, M, and Nakazato, K. The effect of high-intensity interval cycling sprints subsequent to arm-curl exercise on upper-body muscle strength and hypertrophy. J Strength Cond Res 30(8): 2318-2323, 2016-The purpose of this study was to examine whether lower limb sprint interval training (SIT) after arm resistance training (RT) influences training response of arm muscle strength and hypertrophy. Twenty men participated in this study. We divided subjects into RT group (n = 6) and concurrent training group (CT, n = 6). The RT program was designed to induce muscular hypertrophy (3 sets × 10 repetitions [reps] at 80% 1 repetition maximum [1RM] of arm-curl exercise) and was performed in an 8-week training schedule performed 3 times per week on nonconsecutive days. Subjects assigned to the CT group performed identical protocols as strength training and modified SIT (4 sets of 30-s maximal effort, separated in 4 m 30-s rest intervals) on the same day. Pretest and posttest maximal oxygen consumption (V[Combining Dot Above]O2max), muscle cross-sectional area (CSA), and 1RM were measured. Significant increase in V[Combining Dot Above]O2max from pretest to posttest was observed in the CT group (p = 0.010, effect size [ES] = 1.84) but not in the RT group (p = 0.559, ES = 0.35). Significant increase in CSA from pretest to posttest was observed in the RT group (p = 0.030, ES = 1.49) but not in the CT group (p = 0.110, ES = 1.01). Significant increase in 1RM from pretest to posttest was observed in the RT group (p = 0.021, ES = 1.57) but not in the CT group (p = 0.065, ES = 1.19). In conclusion, our data indicate that concurrent lower limb SIT interferes with arm muscle hypertrophy and strength.

ARE EXECUTIVE FUNCTIONING DEFICITS CONCURRENTLY AND PREDICTIVELY ASSOCIATED WITH DEPRESSIVE AND ANXIETY SYMPTOMS IN ADOLESCENTS?

PubMed Central

Han, Georges; Helm, Jonathan; Iucha, Cornelia; Zahn-Waxler, Carolyn; Hastings, Paul D.; Klimes-Dougan, Bonnie

2015-01-01

Background The central objective of the current study was to evaluate how executive functions (EF), and specifically cognitive flexibility, were concurrently and predictively associated with anxiety and depressive symptoms in adolescence. Method Adolescents (N = 220) and their parents participated in this longitudinal investigation. Adolescents’ EF was assessed by the Wisconsin Card Sorting Test (WCST) during the initial assessment, and symptoms of depressive and anxiety disorders were reported by mothers and youths concurrently and two years later. Results Correlational analyses suggested that youths who made more total errors (TE), including both perseverative errors (PE) and non-perseverative errors (NPE), concurrently exhibited significantly more depressive symptoms. Adolescents who made more TE and those who made more NPE tended to have more anxiety symptoms two years later. SEM analyses accounting for key explanatory variables (e.g., IQ, disruptive behavior disorders, and attention deficit hyperactive disorder) showed that TE was concurrently associated with parent reports of adolescent depressive symptoms. Discussion The results suggest internalizing psychopathology is associated with global (TE) and nonspecific (NPE) EF difficulties, but not robustly associated with cognitive inflexibility (PE). Future research with the WCST should consider different sources of errors which are posited to reflect divergent underlying neural mechanisms, conferring differential vulnerability for emerging mental health problems. PMID:26042358

Characterizing Concurrent Tobacco Product Use Among Homeless Cigarette Smokers.

PubMed

Kish, Daniel H; Reitzel, Lorraine R; Kendzor, Darla E; Okamoto, Hiroe; Businelle, Michael S

2015-09-01

Cigarette smoking prevalence rates are high among homeless adults (>70%); however, little is known about concurrent tobacco or other nicotine product use (i.e., concurrent use [CU]) in this population. CU may impact smoking quit rates and confer greater risk of health problems within this vulnerable population. This study characterized CU in a sample of homeless smokers and compared cigarette-only smokers (C-OS) to concurrent users (CUs) on participant characteristics and factors known to be associated with smoking cessation. Participants were 178 adult conventional cigarette smokers from a homeless shelter in Dallas, TX. Sociodemographic characteristics, number of homelessness episodes, tobacco dependence, and items characterizing use of several tobacco/nicotine products over the last 30 days including use frequency, reasons for use, and perceived health risks were described. Sociodemographic characteristics, number of homelessness episodes, tobacco dependence, stress, readiness to quit (RTQ) smoking, and number of smoking quit attempts in the last year were compared between the C-OS and CUs groups using t tests and chi-square tests. CU was prevalent (n = 91; 51.1%), and 49.5% of CUs reported the use of ≥2 products in addition to conventional cigarettes. Compared with C-OS, CUs were younger and had more homelessness episodes, higher expired breath carbon monoxide levels, and higher stress (ps < .05). Groups did not differ on sex, race, other dependence indicators, RTQ, or previous quit attempts. CU is common among homeless smokers. CUs and C-OS did not differ in their RTQ smoking, though greater stress among the CUs may represent a hurdle for cessation. © The Author 2014. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Investigating grounded conceptualization: motor system state-dependence facilitates familiarity judgments of novel tools.

PubMed

Matheson, Heath E; Familiar, Ariana M; Thompson-Schill, Sharon L

2018-03-02

Theories of embodied cognition propose that we recognize tools in part by reactivating sensorimotor representations of tool use in a process of simulation. If motor simulations play a causal role in tool recognition then performing a concurrent motor task should differentially modulate recognition of experienced vs. non-experienced tools. We sought to test the hypothesis that an incompatible concurrent motor task modulates conceptual processing of learned vs. non-learned objects by directly manipulating the embodied experience of participants. We trained one group to use a set of novel, 3-D printed tools under the pretense that they were preparing for an archeological expedition to Mars (manipulation group); we trained a second group to report declarative information about how the tools are stored (storage group). With this design, familiarity and visual attention to different object parts was similar for both groups, though their qualitative interactions differed. After learning, participants made familiarity judgments of auditorily presented tool names while performing a concurrent motor task or simply sitting at rest. We showed that familiarity judgments were facilitated by motor state-dependence; specifically, in the manipulation group, familiarity was facilitated by a concurrent motor task, whereas in the spatial group familiarity was facilitated while sitting at rest. These results are the first to directly show that manipulation experience differentially modulates conceptual processing of familiar vs. unfamiliar objects, suggesting that embodied representations contribute to recognizing tools.

Quantifying Interfacial pH Variation at Molecular Length Scales Using a Concurrent Non-Faradaic Reaction.

PubMed

Ryu, Jaeyune; Wuttig, Anna; Surendranath, Yogesh

2018-05-15

We quantify changes in the interfacial pH local to the electrochemical double layer during electrocatalysis, using a concurrent non-faradaic probe reaction. In the absence of electrocatalysis, nanostructured Pt/C surfaces mediate the reaction of H2 with cis-2-butene-1,4-diol to form a mixture of 1,4-butanediol and n-butanol with a selectivity that is linearly dependent on the bulk solution pH. We show that kinetic branching occurs from a common surface-bound intermediate, ensuring that this probe reaction is uniquely sensitive to the interfacial pH within molecular length scales of the surface. We use the pH-dependent selectivity of this reaction to track changes in interfacial pH during concurrent hydrogen oxidation electrocatalysis and find that the local pH can vary dramatically, > 3 units, relative to the bulk value even at modest current densities in well-buffered electrolytes. This work highlights the key role that interfacial pH variation plays in modulating inner-sphere electrocatalysis. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Yudomian of Siberia, Vendian and Ediacaran systems of the International stratigraphic scale

NASA Astrophysics Data System (ADS)

Khomentovsky, V. V.

2008-12-01

In Russia, the terminal Neoproterozoic formally includes the Vendian of western part of the East European platform and the concurrent Yudoma Group of Siberia. As is shown in this work, the designated subdivisions correspond in the stratotypes only to the upper, Yudomian Series of the Vendian. In the Siberian platform, the Ust-Yudoma and Aim horizons of the Yudomian are tightly interrelated. The lower of them, bearing remains of Ediacaran Fauna, represents the Ediacarian Stage, whereas the upper one containing small-shelled fossils (SSF) corresponds to the Nemakit-Daldynian Stage divided into the trisulcatus and antiqua superregional zones. In more complete sections of the platform periphery, sediments of these subdivisions conformably rest on siliciclastic succession that should be ranked as basal subdivision of the Yudomian. The succession is concurrent to the Laplandian Stage of the East European platform. According to geochronological dates obtained recently, the Yudomian Series spans interval of 600-540 Ma. In the East European platform, the Upper Vendian (Yudomian) begins with the Laplandian basal tillites of synonymous stage. In the west of the platform, tillites are dated at 600 Ma like the Upper Vendian base in Siberia. The next Ediacarian Stage of the East European platform is stratigraphic equivalent of the Redkino Horizon, while summary range of the Kotlin and Rovno horizons is concurrent to that of the Nemakit-Daldynian Stage. The Vendian of Russia is conformably overlain by the Tommotian Stage of the Lower Cambrian. Intense pre-Vendian events constrained distribution areas of the Lower Vendian sediments in Russia. The Lower Vendian deposits of the East European platform are most representative and well studied in the central Urals, where they are attributed to the Serebryanka Group. In Siberia, separate subdivisions representing the Lower Vendian are the Maastakh Formation of the Olenek Uplift, two lower members of the Ushakovka Formation in the Baikal region, and the Taseeva Group of the Yenisei Range. Chronological interval of the Lower Vendian corresponds to 650-600 Ma. The Marinoan Glaciation dated in Australia at 650-635 Ma is concurrent to basal part of the pre-Yudomian interval of the Vendian in Russia, whereas the Laplandian Tillite and Gaskiers Glaciation (600-580 Ma) correspond to onset of the Yudomian Epoch. The new Ediacaran System (Knoll et al., 2004) legalized in the International Neoproterozoic scale is close in range to the entire Vendian (635-544 Ma), although without basal beds (Marinoan Tillite) it deprives the terminal Neoproterozoic of its original sense. Inferiority of the system consists also in its indivisibility into stages. Hence, it is clear that the Vendian System subdivided in detail in Russia should be retained in the rank of terminal system of the Precambrian, one of the basic in general scale of the Neoproterozoic.

Endurance Training Intensity Does Not Mediate Interference to Maximal Lower-Body Strength Gain during Short-Term Concurrent Training

PubMed Central

Fyfe, Jackson J.; Bartlett, Jonathan D.; Hanson, Erik D.; Stepto, Nigel K.; Bishop, David J.

2016-01-01

We determined the effect of concurrent training incorporating either high-intensity interval training (HIT) or moderate-intensity continuous training (MICT) on maximal strength, counter-movement jump (CMJ) performance, and body composition adaptations, compared with single-mode resistance training (RT). Twenty-three recreationally-active males (mean ± SD: age, 29.6 ± 5.5 y; V˙O2peak, 44 ± 11 mL kg−1·min−1) underwent 8 weeks (3 sessions·wk−1) of either: (1) HIT combined with RT (HIT+RT group, n = 8), (2) work-matched MICT combined with RT (MICT+RT group, n = 7), or (3) RT performed alone (RT group, n = 8). Measures of aerobic capacity, maximal (1-RM) strength, CMJ performance and body composition (DXA) were obtained before (PRE), mid-way (MID), and after (POST) training. Maximal (one-repetition maximum [1-RM]) leg press strength was improved from PRE to POST for RT (mean change ± 90% confidence interval; 38.5 ± 8.5%; effect size [ES] ± 90% confidence interval; 1.26 ± 0.24; P < 0.001), HIT+RT (28.7 ± 5.3%; ES, 1.17 ± 0.19; P < 0.001), and MICT+RT (27.5 ± 4.6%, ES, 0.81 ± 0.12; P < 0.001); however, the magnitude of this change was greater for RT vs. both HIT+RT (7.4 ± 8.7%; ES, 0.40 ± 0.40) and MICT+RT (8.2 ± 9.9%; ES, 0.60 ± 0.45). There were no substantial between-group differences in 1-RM bench press strength gain. RT induced greater changes in peak CMJ force vs. HIT+RT (6.8 ± 4.5%; ES, 0.41 ± 0.28) and MICT+RT (9.9 ± 11.2%; ES, 0.54 ± 0.65), and greater improvements in maximal CMJ rate of force development (RFD) vs. HIT+RT (24.1 ± 26.1%; ES, 0.72 ± 0.88). Lower-body lean mass was similarly increased for RT (4.1 ± 2.0%; ES; 0.33 ± 0.16; P = 0.023) and MICT+RT (3.6 ± 2.4%; ES; 0.45 ± 0.30; P = 0.052); however, this change was attenuated for HIT+RT (1.8 ± 1.6%; ES; 0.13 ± 0.12; P = 0.069). We conclude that concurrent training incorporating either HIT or work-matched MICT similarly attenuates improvements in maximal lower-body strength and indices of CMJ performance compared with RT performed alone. This suggests endurance training intensity is not a critical mediator of interference to maximal strength gain during short-term concurrent training. PMID:27857692

Endurance Training Intensity Does Not Mediate Interference to Maximal Lower-Body Strength Gain during Short-Term Concurrent Training.

PubMed

Fyfe, Jackson J; Bartlett, Jonathan D; Hanson, Erik D; Stepto, Nigel K; Bishop, David J

2016-01-01

We determined the effect of concurrent training incorporating either high-intensity interval training (HIT) or moderate-intensity continuous training (MICT) on maximal strength, counter-movement jump (CMJ) performance, and body composition adaptations, compared with single-mode resistance training (RT). Twenty-three recreationally-active males (mean ± SD: age, 29.6 ± 5.5 y; [Formula: see text], 44 ± 11 mL kg -1 ·min -1 ) underwent 8 weeks (3 sessions·wk -1 ) of either: (1) HIT combined with RT (HIT+RT group, n = 8), (2) work-matched MICT combined with RT (MICT+RT group, n = 7), or (3) RT performed alone (RT group, n = 8). Measures of aerobic capacity, maximal (1-RM) strength, CMJ performance and body composition (DXA) were obtained before (PRE), mid-way (MID), and after (POST) training. Maximal (one-repetition maximum [1-RM]) leg press strength was improved from PRE to POST for RT (mean change ± 90% confidence interval; 38.5 ± 8.5%; effect size [ES] ± 90% confidence interval; 1.26 ± 0.24; P < 0.001), HIT+RT (28.7 ± 5.3%; ES, 1.17 ± 0.19; P < 0.001), and MICT+RT (27.5 ± 4.6%, ES, 0.81 ± 0.12; P < 0.001); however, the magnitude of this change was greater for RT vs. both HIT+RT (7.4 ± 8.7%; ES, 0.40 ± 0.40) and MICT+RT (8.2 ± 9.9%; ES, 0.60 ± 0.45). There were no substantial between-group differences in 1-RM bench press strength gain. RT induced greater changes in peak CMJ force vs. HIT+RT (6.8 ± 4.5%; ES, 0.41 ± 0.28) and MICT+RT (9.9 ± 11.2%; ES, 0.54 ± 0.65), and greater improvements in maximal CMJ rate of force development (RFD) vs. HIT+RT (24.1 ± 26.1%; ES, 0.72 ± 0.88). Lower-body lean mass was similarly increased for RT (4.1 ± 2.0%; ES; 0.33 ± 0.16; P = 0.023) and MICT+RT (3.6 ± 2.4%; ES; 0.45 ± 0.30; P = 0.052); however, this change was attenuated for HIT+RT (1.8 ± 1.6%; ES; 0.13 ± 0.12; P = 0.069). We conclude that concurrent training incorporating either HIT or work-matched MICT similarly attenuates improvements in maximal lower-body strength and indices of CMJ performance compared with RT performed alone. This suggests endurance training intensity is not a critical mediator of interference to maximal strength gain during short-term concurrent training.

Intraclass Correlation Coefficients in Hierarchical Design Studies with Discrete Response Variables: A Note on a Direct Interval Estimation Procedure

ERIC Educational Resources Information Center

Raykov, Tenko; Marcoulides, George A.

2015-01-01

A latent variable modeling procedure that can be used to evaluate intraclass correlation coefficients in two-level settings with discrete response variables is discussed. The approach is readily applied when the purpose is to furnish confidence intervals at prespecified confidence levels for these coefficients in setups with binary or ordinal…

Comparison of Random Forest and Parametric Imputation Models for Imputing Missing Data Using MICE: A CALIBER Study

PubMed Central

Shah, Anoop D.; Bartlett, Jonathan W.; Carpenter, James; Nicholas, Owen; Hemingway, Harry

2014-01-01

Multivariate imputation by chained equations (MICE) is commonly used for imputing missing data in epidemiologic research. The “true” imputation model may contain nonlinearities which are not included in default imputation models. Random forest imputation is a machine learning technique which can accommodate nonlinearities and interactions and does not require a particular regression model to be specified. We compared parametric MICE with a random forest-based MICE algorithm in 2 simulation studies. The first study used 1,000 random samples of 2,000 persons drawn from the 10,128 stable angina patients in the CALIBER database (Cardiovascular Disease Research using Linked Bespoke Studies and Electronic Records; 2001–2010) with complete data on all covariates. Variables were artificially made “missing at random,” and the bias and efficiency of parameter estimates obtained using different imputation methods were compared. Both MICE methods produced unbiased estimates of (log) hazard ratios, but random forest was more efficient and produced narrower confidence intervals. The second study used simulated data in which the partially observed variable depended on the fully observed variables in a nonlinear way. Parameter estimates were less biased using random forest MICE, and confidence interval coverage was better. This suggests that random forest imputation may be useful for imputing complex epidemiologic data sets in which some patients have missing data. PMID:24589914

Satisfaction with physical and social surroundings and the habit of smoking cigarettes in the metropolitan area of Belo Horizonte, Brazil.

PubMed

Souza, Ricardo Alexandre de; Oliveira, Cláudia Di Lorenzo; Lima-Costa, Maria Fernanda; Proietti, Fernando Augusto

2014-01-01

The objective of this study was to examine the association between individual satisfaction with social and physical surroundings and the habit of smoking cigarettes. Data from the Health Survey of Adults from the metropolitan area of Belo Horizonte, Minas Gerais, Brazil, were used. Based on a probability sample, participants (n = 12,299) were selected among residents aged 20 years old or more. The response variable was the smoking habit and the explanatory variable of interest was the neighborhood perception. Potential confounding variables included demographic characteristics, health behaviors and other indicators of socioeconomic position. The prevalence of current smokers, former smokers and never smokers were 20.8, 14.1 and 65.1%, respectively; 74.4 and 25.5% of the participants were categorized as being more satisfied and less satisfied with the neighborhood, respectively. Compared to those who never smoked, former smokers (adjusted odds ratio = 1.40, 95% confidence interval 1.20 - 1.62) and current smokers (adjusted odds ratio = 1.17, 95% confidence interval 1.03 - 1.34) were less satisfied with the neighborhood compared to those who never smoked. The results of this study indicate there is an independent association between the smoking habit and a less satisfying neighborhood perception in the metropolitan region of Belo Horizonte, which does not depend on individual characteristics, traditionally reported as being associated with smoking.

Comparison of random forest and parametric imputation models for imputing missing data using MICE: a CALIBER study.

PubMed

Shah, Anoop D; Bartlett, Jonathan W; Carpenter, James; Nicholas, Owen; Hemingway, Harry

2014-03-15

Multivariate imputation by chained equations (MICE) is commonly used for imputing missing data in epidemiologic research. The "true" imputation model may contain nonlinearities which are not included in default imputation models. Random forest imputation is a machine learning technique which can accommodate nonlinearities and interactions and does not require a particular regression model to be specified. We compared parametric MICE with a random forest-based MICE algorithm in 2 simulation studies. The first study used 1,000 random samples of 2,000 persons drawn from the 10,128 stable angina patients in the CALIBER database (Cardiovascular Disease Research using Linked Bespoke Studies and Electronic Records; 2001-2010) with complete data on all covariates. Variables were artificially made "missing at random," and the bias and efficiency of parameter estimates obtained using different imputation methods were compared. Both MICE methods produced unbiased estimates of (log) hazard ratios, but random forest was more efficient and produced narrower confidence intervals. The second study used simulated data in which the partially observed variable depended on the fully observed variables in a nonlinear way. Parameter estimates were less biased using random forest MICE, and confidence interval coverage was better. This suggests that random forest imputation may be useful for imputing complex epidemiologic data sets in which some patients have missing data.

Concurrent Anemia and Elevated C-Reactive Protein Predicts HIV Clinical Treatment Failure, Including Tuberculosis, After Antiretroviral Therapy Initiation

PubMed Central

Shivakoti, Rupak; Yang, Wei-Teng; Gupte, Nikhil; Berendes, Sima; Rosa, Alberto La; Cardoso, Sandra W.; Mwelase, Noluthando; Kanyama, Cecilia; Pillay, Sandy; Samaneka, Wadzanai; Riviere, Cynthia; Sugandhavesa, Patcharaphan; Santos, Brento; Poongulali, Selvamuthu; Tripathy, Srikanth; Bollinger, Robert C.; Currier, Judith S.; Tang, Alice M.; Semba, Richard D.; Christian, Parul; Campbell, Thomas B.; Gupta, Amita

2015-01-01

Background. Anemia is a known risk factor for clinical failure following antiretroviral therapy (ART). Notably, anemia and inflammation are interrelated, and recent studies have associated elevated C-reactive protein (CRP), an inflammation marker, with adverse human immunodeficiency virus (HIV) treatment outcomes, yet their joint effect is not known. The objective of this study was to assess prevalence and risk factors of anemia in HIV infection and to determine whether anemia and elevated CRP jointly predict clinical failure post-ART. Methods. A case-cohort study (N = 470 [236 cases, 234 controls]) was nested within a multinational randomized trial of ART efficacy (Prospective Evaluation of Antiretrovirals in Resource Limited Settings [PEARLS]). Cases were incident World Health Organization stage 3, 4, or death by 96 weeks of ART treatment (clinical failure). Multivariable logistic regression was used to determine risk factors for pre-ART (baseline) anemia (females: hemoglobin <12.0 g/dL; males: hemoglobin <13.0 g/dL). Association of anemia as well as concurrent baseline anemia and inflammation (CRP ≥10 mg/L) with clinical failure were assessed using multivariable Cox models. Results. Baseline anemia prevalence was 51% with 15% prevalence of concurrent anemia and inflammation. In analysis of clinical failure, multivariate-adjusted hazard ratios were 6.41 (95% confidence interval [CI], 2.82–14.57) for concurrent anemia and inflammation, 0.77 (95% CI, .37–1.58) for anemia without inflammation, and 0.45 (95% CI, .11–1.80) for inflammation without anemia compared to those without anemia and inflammation. Conclusions. ART-naive, HIV-infected individuals with concurrent anemia and inflammation are at particularly high risk of failing treatment, and understanding the pathogenesis could lead to new interventions. Reducing inflammation and anemia will likely improve HIV disease outcomes. Alternatively, concurrent anemia and inflammation could represent individuals with occult opportunistic infections in need of additional screening. PMID:25828994

Concurrent Heroin Use and Correlates among Methadone Maintenance Treatment Clients: A 12-Month Follow-up Study in Guangdong Province, China

PubMed Central

Luo, Xiaofeng; Zhao, Peizhen; Gong, Xiao; Zhang, Lei; Tang, Weiming; Zou, Xia; Chen, Wen; Ling, Li

2016-01-01

Objective: To assess concurrent heroin use and correlates among Methadone Maintenance Treatment (MMT) clients in Guangdong Province, China. Method: Demographic and drug use data were collected with a structured questionnaire, and MMT information was obtained from the MMT clinic registration system in Guangdong. Human immunodeficiency virus (HIV-) and hepatitis C virus (HCV) infected status and urine morphine results were obtained from laboratory tests. Logistic regressions were employed to investigate the factors associated with concurrent heroin use. Results: Among the 6848 participants, 75% continued using heroin more than once during the first 12 months after treatment initiation. Concurrent heroin use was associated with inharmonious family relationship (OR (odds ratio) = 1.49, 95% CI (confidence intervals): 1.24–1.78), HIV positivity (OR = 1.25, 95% CI: 1.01–1.55), having multiple sex partners (OR = 1.34, 95% CI: 1.07–1.69), having ever taken intravenous drugs (OR = 0.81, 95% CI: 0.69–0.95), higher maintenance dose (OR = 1.13, 95% CI: 1.01–1.28) and poorer MMT attendance (OR<20% = 1.32, 95% CI: 1.13–1.53; OR20%– = 1.33, 95% CI: 1.14–1.54; OR50%– = 1.69, 95% CI: 1.44–2.00). Among those who used heroin concurrently, the same factors, and additionally being older (OR35– = 1.26, 95% CI: 1.11–1.43; OR≥45 = 1.63, 95% CI: 1.30–2.05) and female (OR = 1.60, 95% CI: 1.28–2.00), contribute to a greater frequency of heroin use. Conclusions: Concurrent heroin use was prevalent among MMT participants in Guangdong, underscoring the urgent needs for tailored interventions and health education programs for this population. PMID:27005649

Concurrent Transmission Based on Channel Quality in Ad Hoc Networks: A Game Theoretic Approach

NASA Astrophysics Data System (ADS)

Chen, Chen; Gao, Xinbo; Li, Xiaoji; Pei, Qingqi

In this paper, a decentralized concurrent transmission strategy in shared channel in Ad Hoc networks is proposed based on game theory. Firstly, a static concurrent transmissions game is used to determine the candidates for transmitting by channel quality threshold and to maximize the overall throughput with consideration of channel quality variation. To achieve NES (Nash Equilibrium Solution), the selfish behaviors of node to attempt to improve the channel gain unilaterally are evaluated. Therefore, this game allows each node to be distributed and to decide whether to transmit concurrently with others or not depending on NES. Secondly, as there are always some nodes with lower channel gain than NES, which are defined as hunger nodes in this paper, a hunger suppression scheme is proposed by adjusting the price function with interferences reservation and forward relay, to fairly give hunger nodes transmission opportunities. Finally, inspired by stock trading, a dynamic concurrent transmission threshold determination scheme is implemented to make the static game practical. Numerical results show that the proposed scheme is feasible to increase concurrent transmission opportunities for active nodes, and at the same time, the number of hunger nodes is greatly reduced with the least increase of threshold by interferences reservation. Also, the good performance on network goodput of the proposed model can be seen from the results.

Advanced Electrocardiographic Predictors of Sudden Death in Familial Dysautonomia

NASA Technical Reports Server (NTRS)

Solaimanzadeh, I.; Schlegel, T. T.; Greco, E. C.; DePalma, J. L.; Starc, V.; Marthol, H.; Tutaj, M.; Buechner, S.; Axelrod, F. B.; Hilz, M. J.

2007-01-01

To identify accurate predictors for the risk of sudden death in patients with familial dysautonomia (FD). Ten-minute resting high-fidelity 12-lead ECGs were obtained from 14 FD patients and 14 age/gender-matched healthy subjects. Multiple conventional and advanced ECG parameters were studied for their ability to predict sudden death in FD over a subsequent 4.5-year period, including multiple indices of linear and non-linear heart rate variability (HRV); QT variability; waveform complexity; high frequency QRS; and derived Frank-lead parameters. Four of the 14 FD patients died suddenly during the follow-up period, usually with concomitant pulmonary disorder. The presence of low vagally-mediated HRV was the ECG finding most predictive of sudden death. Concomitant left ventricular hypertrophy and other ECG abnormalities such as increased QTc and JTc intervals, spatial QRS-T angles, T-wave complexity, and QT variability were also present in FD patients, suggesting that structural heart disease is fairly common in FD. Although excessive or unopposed cardiac vagal (relative to sympathetic) activity has been postulated as a contributor to sudden death in FD, the presence of low vagally-mediated HRV was paradoxically the best predictor of sudden death. However, we suggest that low vagally-mediated HRV be construed not as a direct cause of sudden death in FD, but rather as an effect of concurrent pathological processes, especially hypoxia due to pulmonary disorders and sleep apnea, that themselves increase the risk of sudden death in FD and simultaneously diminish HRV. We speculate that adenosine may play a role in sudden death in FD, possibly independently of vagal activity, and that adenosine inhibitors such as theophylline might therefore be useful as prophylaxis in this disorder.

Low dimensional model of heart rhythm dynamics as a tool for diagnosing the anaerobic threshold

NASA Astrophysics Data System (ADS)

Anosov, O. L.; Butkovskii, O. Ya.; Kadtke, J.; Kravtsov, Yu. A.; Protopopescu, V.

1997-05-01

We report preliminary results on describing the dependence of the heart rhythm variability on the stress level by using qualitative, low dimensional models. The reconstruction of macroscopic heart models yielding cardio cycles (RR-intervals) duration was based on actual clinical data. Our results show that the coefficients of the low dimensional models are sensitive to metabolic changes. In particular, at the transition between aerobic and aerobic-anaerobic metabolism, there are pronounced extrema in the functional dependence of the coefficients on the stress level. This strong sensitivity can be used to design an easy indirect method for determining the anaerobic threshold. This method could replace costly and invasive traditional methods such as gas analysis and blood tests.

The application of dimensional analysis to the problem of solar wind-magnetosphere energy coupling

NASA Technical Reports Server (NTRS)

Bargatze, L. F.; Mcpherron, R. L.; Baker, D. N.; Hones, E. W., Jr.

1984-01-01

The constraints imposed by dimensional analysis are used to find how the solar wind-magnetosphere energy transfer rate depends upon interplanetary parameters. The analyses assume that only magnetohydrodynamic processes are important in controlling the rate of energy transfer. The study utilizes ISEE-3 solar wind observations, the AE index, and UT from three 10-day intervals during the International Magnetospheric Study. Simple linear regression and histogram techniques are used to find the value of the magnetohydrodynamic coupling exponent, alpha, which is consistent with observations of magnetospheric response. Once alpha is estimated, the form of the solar wind energy transfer rate is obtained by substitution into an equation of the interplanetary variables whose exponents depend upon alpha.

Have the temperature time series a structural change after 1998?

NASA Astrophysics Data System (ADS)

Werner, Rolf; Valev, Dimitare; Danov, Dimitar

2012-07-01

The global and hemisphere temperature GISS and Hadcrut3 time series were analysed for structural changes. We postulate the continuity of the preceding temperature function depending from the time. The slopes are calculated for a sequence of segments limited by time thresholds. We used a standard method, the restricted linear regression with dummy variables. We performed the calculations and tests for different number of thresholds. The thresholds are searched continuously in determined time intervals. The F-statistic is used to obtain the time points of the structural changes.

Behavioral contrast with timeout, blackout, or extinction as the negative condition1

PubMed Central

Sadowsky, Stephen

1973-01-01

When either a timeout period (darkening the response key) or a blackout period (darkening both chamber and response key) was alternated with a stimulus associated with variable-interval reinforcement, behavioral contrast was obtained. Either peck contrast or maintained contrast occurred, depending on whether or not responding was evidenced during the negative condition. These results are contrary to recent accounts emphasizing the role of non-reinforced responding in the production of contrast, but are consistent with interpretations emphasizing the aversiveness of the negative condition. PMID:16811680