bluuebunny/crossref_metadata_2025_split huggingface dataset:
Automatization in second language acquisition: What does the coefficient of variation tell us?
Authors: HULSTIJN JAN H. , VAN GELDEREN AMOS , SCHOONEN ROB 
Published: July 2009

ABSTRACTSegalowitz and Segalowitz distinguish between “speedup” (mean reaction time [RT] and mean standard deviation of responses in an RT task decrease to the same degree) and “automatization” (mean standard deviation decreases more than mean RT). The coefficient of variation, which is the standard deviation divided by the mean RT, decreases in the case of automatization while remaining unchanged in the case of speedup. We present data that are collected in two studies. The first one is a longitudinal study spanning 2 years and comprising four RT tasks, both in second language (L2) English and first language Dutch (N> 200). The second study is an English L2 word training study. Students (N= 41) performed a lexical decision task before and after training. Convincing evidence for automatization was not found in either study. The main problems in testing the Segalowitz and Segalowitz hypothesis is that gains in knowledge itself and gains in processing it cannot be adequately disentangled in the RT tasks currently used, characterized by a speed–accuracy trade-off. Althoughconceptuallyskill acquisition can be distinguished from knowledge accumulation,in reality, knowledge accumulation forms part of skill acquisition because, in real L2 learning, exposure to new words goes hand in hand with exposure to words encountered previously.
Effects of adding interword spacing on Chinese reading: A comparison of Chinese native readers and English readers of Chinese as a second language
Authors: BASSETTI BENEDETTA 
Published: July 2009

ABSTRACTEnglish is written with interword spacing, and eliminating it negatively affects English readers. Chinese is written without interword spacing, and adding it does not facilitate Chinese readers.Pinyin(romanized Chinese) is written with interword spacing. This study investigated whether adding interword spacing facilitates reading in Chinese native readers and English readers of Chinese as a second language. Participants performed two sentence–picture verification tasks with sentences written withpinyinorhanzi(characters). Interword spacing facilitated pinyin reading in English readers but not in Chinese readers; it did not affect hanzi reading in either group. The effects of interword spacing on second language reading appear to be determined by characteristics of both readers' first language writing system and the writing system being read.
Sensitivity Analysis for the System Reliability Function
Authors: Fishman George S. 
Published: July 2009

Sensitivity analysis is an integral part of virtually every study of system reliability. This paper describes a Monte Carlo sampling plan for estimating this sensitivity in system reliability to changes in component reliabilities. The unique feature of the approach is that sample data collected on K independent replications using a specified component reliability vector p are transformed by an importance function into unbiased estimates of system reliability for each component reliability vector q in a set of vectors Q. Moreover, this importance function together with available prior information about the given system enables one to produce estimates that require considerably less computing time to achieve a specified accuracy for all |Q| reliability estimates than a set of |Q| crude Monte Carlo sampling experiments would require to estimate each of the |Q| system reliabilities separately. As the number of components in the system grows, the relative efficiency continues to favor the proposed method.The paper shows the intimate relationship between the proposal and the method of control variates. Next, it relates the proposal to the estimation of coefficients in a reliability polynomial and indicates how this concept can be used to improve computing efficiency in certain cases. It also describes a procedure that determines the p vector, to be used in the sampling experiment, that minimizes a bound on the worst-case variance. The paper also derives individual and simultaneous confidence intervals that hold for every fixed sample size K. An example illustrates how the proposal works in an s-t connectedness problem.
Strongly Consistent Steady-State Derivative Estimates
Authors: Glasserman Paul , Hu Jian-Qiang , Strickland Stephen G. 
Published: July 2009

We establish strong consistency (i.e., almost sure convergence) of infinitesimal perturbation analysis (IPA) estimators of derivatives of steady-state means for a broad class of systems. Our results substantially extend previously available results on steady-state derivative estimation via IPA.Our basic assumption is that the process under study is regenerative, but our analysis uses regenerative structure in an indirect way: IPA estimators are typically biased over regenerative cycles, so straightforward differentiation of the regenerative ratio formula does not necessarily yield a valid estimator of the derivative of a steady-state mean. Instead, we use regeneration to pass from unbiasedness over fixed, finite time horizons to convergence as the time horizon grows. This provides a systematic way of extending results on unbiasedness to strong consistency.Given that the underlying process regenerates, we provide conditions under which a certain augmented process is also regenerative. The augmented process includes additional information needed to evaluate derivatives; derivatives of time averages of the original process are time averages of the augmented process. Thus, through this augmentation we are able to apply standard renewal theory results to the convergence of derivatives.
Gated, Exhaustive, Parallel Service
Authors: Browne Sid , CoffmanJR. E. G. , Gilbert E. N. , Wright Paul E. 
Published: July 2009

We analyze gated, exhaustive service of an infinite-server system with vacations. Customers enter a queue in a Poisson stream. The servers, working in parallel, serve customers in stages. A stage begins with all customers transferred from the queue to the servers (the gate opens). The servers then begin serving these customers, all simultaneously. The stage ends when their services are completed. Service is exhaustive because the servers must again examine the queue to see if any new customers arrived during the last stage. If there are any, a new stage begins. If there are none, the servers move on to other work. The time spent away from the queue is called vacation time. The queue may represent a node or station in a data transmission network and the servers may be communication channels.We analyze the equilibrium behavior of the number of requests served during a stage for general service and vacation time distributions. This analysis leads to the solution of a Fredholm integral equation of the second kind. We find conditions under which the system is stable and compute bounds on performance metrics of interest. Approximate techniques are introduced and tested. Finally, an extension to polling systems is studied.
An Error-Bound Theorem for Approximate Markov Chains
Authors: Dijk Nico M. Van 
Published: July 2009

Recently an error-bound theorem was reported to conclude analytic error bounds for approximate Markov chains. The theorem required a uniform bound for marginal expectations of the approximate model. This note will relax this bound to steady state rather than marginal expectations as of practical interest(i) to simplify verification and/or(ii) to obtain a more accurate error bound.A communication model is studied in detail to support the results.
Optimality of Randomized Trunk Reservation
Authors: Feinberg Eugene A. , Reiman Martin I. 
Published: July 2009

We consider a controlled queueing system that is a generalization of the M/M/c/W queue. There are m types of customers that arrive according to independent Poisson processes. Service times are exponential and independent and do not depend on the customer type. There is room in the system for a total of N customers; if there are N customers in the system, new arrivals are lost. Type j customers are more profitable than type (j + 1 ) customers, j = 2,…, m —, and type 1 customers are at least as profitable as type 2 customers. The allowed control is to accept or reject customers at arrival. No preemption of customers in service is allowed. The goal is to maximize the average reward per unit of time subject to a constraint that the blocking probability of type 1 customers is no greater than a given level.For an M/M/c/c system without a constraint, Miller [12] proved that an optimal policy has a simple threshold structure. We show that, for the constrained problem described above, an optimal policy has a similar structure, but one of the thresholds might have to be randomized. We also derive an algorithm that constructs an optimal policy and describe other forms of optimal policies.
On the Modular Value and Fractional Part of a Random Variable
Authors: Herschkorn Stephen J. 
Published: July 2009

Let X be a random variable with characteristic function ϕ. In the case where X is integer-valued and n is a positive integer, a formula (in terms of ϕ) for the probability that n divides X is presented. The derivation of this formula is quite simple and uses only the basic properties of expectation and complex numbers. The formula easily generalizes to one for the distribution of X mod n. Computational simplifications and the relation to the inversion formula are also discussed; the latter topic includes a new inversion formula when the range of X is finite.When X may take on a more general distribution, limiting considerations of the previous formulas suggest others for the distribution, density, and moments of the fractional part X — [X]. These are easily derived using basic properties of Fourier series. These formulas also yield an alternative inversion formula for ϕ when the range of X is bounded.Applications to renewal theory and random walks are suggested. A by-product of the approach is a probabilistic method for the evaluation of infinite series.
Optimal Discrete Adjustments for Short Production Runs
Authors: Wiel Scott A. Vander 
Published: July 2009

Diameter measurements on successive metal hubs from a machining operation are modeled using a random walk with observation error and linear drift corresponding to tool wear. After producing and measuring a hub, the depth of the cutting tool on the lathe can be adjusted in integer multiples of 0.0001 inches. How should the tool be adjusted?An optimal discrete adjustment strategy is derived assuming that the lathe automatically corrects for deterministic tool wear. The objective is to minimize expected run costs proportional to the sum of squared diameter deviations from a target plus fixed charges for manual tool adjustments. The optimal strategy makes no manual adjustment if an estimate of the process mean is near target. Otherwise, an adjustment is made to return the estimated mean as near to target as possible within the adjustment resolution.The region where no adjustments are made widens near the end of the production run where adjustments have only short-term impact. The region converges as the number of remaining periods increases. Plots of expected run costs show that the extra cost of discreteness is small at high resolution but is substantial when the adjustment grid is coarse.
The Reversed Hazard Rate Function
Authors: Block Henry W. , Savits Thomas H. , Singh Harshinder 
Published: July 2009

In this paper we discuss some properties of the reversed hazard rate function. This function has been shown to be useful in the analysis of data in the presence of left censored observations. It is also natural in discussing lifetimes with reversed time scale. In fact, ordinary hazard rate functions are most useful for lifetimes, and reverse hazard rates are natural if the time scale is reversed. Mixing up these concepts can often, although not always, lead to anomalies. For example, one result gives that if the reversed hazard rate function is increasing, its interval of support must be (—∞, b) where b is finite. Consequently nonnegative random variables cannot have increasing reversed hazard rates. Because of this result some existing results in the literature on the reversed hazard rate ordering require modification.Reversed hazard rates are also important in the study of systems. Hazard rates have an affinity to series systems; reversed hazard rates seem more appropriate for studying parallel systems. Several results are given that demonstrate this. In studying systems, one problem is to relate derivatives of hazard rate functions and reversed hazard rate functions of systems to similar quantities for components. We give some results that address this. Finally, we carry out comparisons for k-out-of-n systems with respect to the reversed hazard rate ordering.
Incidence of common respiratory viral infections related to climate factors in hospitalized children in Hong Kong
Authors: TANG J. W. , LAI F. Y. L. , WONG F. , HON K. L. E. 
Published: July 2009

SUMMARYHong Kong has a subtropical climate and an influenza seasonality lying approximately mid-way (March–June) between those of the Northern (November–March) and Southern (June–September) hemispheres. Respiratory syncytial virus (RSV) shares a similar seasonality to that of influenza in Hong Kong and is another important respiratory infection of childhood. Daily virus incidence data from public hospitals in Hong Kong's New Territory East Cluster, together with Hong Kong climate data were obtained for 2000–2007. Statistical time-series analysis using monthly time windows showed that influenza A and RSV incidence increased with higher environmental relative humidity, whereas influenza B incidence decreased with higher environmental temperatures. The other climate variables (including vapour pressure as a measure of absolute humidity) were not significantly related to the incidence of these respiratory viruses. Data from this study further reinforces the concept that the relationship between climate factors and respiratory virus incidence differ between subtropical/tropical and temperate countries.
Child maltreatment, attachment, and the self system: Emergence of an internal state lexicon in toddlers at high social risk
Authors: Beeghly Marjorie , Cicchetti Dante 
Published: July 2009

AbstractThe ability to talk about the internal states (ISs) and feelings of self and other is an age-appropriate development of late toddlerhood hypothesized to reflect toddlers' emergent self–other understanding and to be fundamental to the regulation of social interaction. This study examined the effects of child maltreatment on the emergence of low-socioeconomic status 30-month-old toddlers' IS lexicons. Children's lexicons were derived both from maternal interviews and from observations of children's spontaneous IS utterances in four laboratory contexts. Results from both data sources indicated that maltreated toddlers produced significantly fewer IS words, fewer IS word types, and proportionately fewer IS words denoting physiological states and negative affect than nonmaltreated toddlers. In addition, maltreated toddlers were more context bound in IS language use and more restricted in their attributions of internal states to self and other. Gender differences were also observed. Individual differences in children's IS language production were significantly related to general linguistic maturity in both groups but to toddlers' conversational skills only in the comparison group. In addition, a cumulative risk model describing the effects of the child's attachment relationship with the caregiver on early IS language was tested. Toddlers most severely at risk (maltreated/insecure) had the most compromised IS language. Thus, secure attachment may serve as a protective mechanism against self-dysfunction in maltreated toddlers.
Errorless learning and elaborative self-generation in healthy older adults and individuals with amnestic mild cognitive impairment: Mnemonic benefits and mechanisms
Authors: LUBINSKY TOBI , RICH JILL B. , ANDERSON NICOLE D. 
Published: July 2009

AbstractErrorless learning is an intervention that benefits memory performance in healthy older adults and a variety of clinical populations. A limitation of the errorless learning technique is that it is passive and does not involve elaborative processing. We report two studies investigating the added benefits of elaborative, self-generated learning to the errorless learning advantage. We also explored the mnemonic mechanisms of the errorless learning advantage. In both studies, older adults and individuals with amnestic mild cognitive impairment (aMCI) completed four encoding conditions representing the crossing of errorless/errorful learning and self-generated/experimenter-provided learning. Self-generation enhanced the errorless learning benefit in cued recall and cued recognition, but not in free recall or item recognition. An errorless learning advantage was observed for priming of target words, and this effect was amplified for participants with aMCI after self-generated learning. Moreover, the aMCI group showed significant priming of prior self-generated errors. These results demonstrate that self-generation enhances the errorless learning advantage when study and test conditions match. The data also support the argument that errorless learning eliminates the misleading implicit influence of prior errors, as well as the need for explicit memory processes to distinguish targets from errors. (JINS, 2009, 15, 704–716.)
FURTHER RESULTS ON POSITIVE PERIODIC SOLUTIONS OF IMPULSIVE FUNCTIONAL DIFFERENTIAL EQUATIONS AND APPLICATIONS
Authors: LIU YUJI 
Published: July 2009

AbstractA class of first-order impulsive functional differential equations with forcing terms is considered. It is shown that, under certain assumptions, there exist positive T-periodic solutions, and under some other assumptions, there exists no positive T-periodic solution. Applications and examples are given to illustrate the main results.
A METHOD OF IMPROVING OAR EFFICIENCY
Authors: BREARLEY MAURICE N. 
Published: July 2009

AbstractIn boats used for competitive rowing it is traditional for the rowers to use strokes in which the angle between the oar shaft and the perpendicular to the hull centre line is much greater at the catch than it is at the end of the power stroke. As a result, the oar blade is even more inefficient in its action at the catch than it is at the end of the power stroke. This paper shows how boat performance in a race would be improved by reducing the difference in these starting and finishing angles. The claim of improved race performance is supported by a detailed investigation of the dynamics involved in the case of a particular coxless pair whose performance has been recorded by the Australian Institute of Sport. We also suggest an easy way to make the necessary change in boat design.
Climate modelling of mass-extinction events: a review
Authors: Feulner Georg 
Published: July 2009

AbstractDespite tremendous interest in the topic and decades of research, the origins of the major losses of biodiversity in the history of life on Earth remain elusive. A variety of possible causes for these mass-extinction events have been investigated, including impacts of asteroids or comets, large-scale volcanic eruptions, effects from changes in the distribution of continents caused by plate tectonics, and biological factors, to name but a few. Many of these suggested drivers involve or indeed require changes of Earth's climate, which then affect the biosphere of our planet, causing a global reduction in the diversity of biological species. It can be argued, therefore, that a detailed understanding of these climatic variations and their effects on ecosystems are prerequisites for a solution to the enigma of biological extinctions. Apart from investigations of the paleoclimate data of the time periods of mass extinctions, climate-modelling experiments should be able to shed some light on these dramatic events. Somewhat surprisingly, however, only a few comprehensive modelling studies of the climate changes associated with extinction events have been undertaken. These studies will be reviewed in this paper. Furthermore, the role of modelling in extinction research in general and suggestions for future research are discussed.
Extending the Foundational Model of Anatomy with Automatically Acquired Spatial Relations
Authors: Möller Manuel , Folz Christian , Sintek Michael , Seifert Sascha , Wennerberg Pinar 
Published: July 2009

AbstractFormal ontologies have made significant impact in bioscience over the last ten years. Among them, the Foundational Model of Anatomy Ontology (FMA) is the most comprehensive model for the spatio-structural representation of human anatomy. In the research project MEDICO we use the FMA as our main source of background knowledge about human anatomy. Our ultimate goals are to use spatial knowledge from the FMA (1) to improve automatic parsing algorithms for 3D volume data sets generated by Computed Tomography and Magnetic Resonance Imaging and (2) to generate semantic annotations using the concepts from the FMA to allow semantic search on medical image repositories. We argue that in this context more spatial relation instances are needed than those currently available in the FMA. In this publication we present a technique for the automatic inductive acquisition of spatial relation instances by generalizing from expert-annotated volume datasets.
Effects of It Takes Two to Talk—The Hanen Program for Parents of Preschool Children With Cerebral Palsy: Findings From an Exploratory Study
Authors: Pennington Lindsay , Thomson Kirsty , James Peter , Martin Laura , McNally Richard 
Published: July 2009

PurposeTo investigate whether It Takes Two to Talk—The Hanen Program for Parents of Preschool Children With Cerebral Palsy is associated with change in interaction between children who have motor disorders and their parents.MethodEleven children aged 19–36 months who had nonprogressive motor disorders that affected their communication, and their mothers, were observed 4 months and 1 month before mothers attended It Takes Two to Talk training, and 1 month and 4 months after its completion.ResultsInteraction patterns were stable prior to training. After training, mothers initiated less and produced more responses and fewer requests. Children produced more initiations, as well as more requests and provisions of information, after training. Mothers' linguistic input did not change in amount or complexity. Changes were maintained 4 months later. Mothers' views of parenting did not change.ConclusionsIt Takes Two to Talk may be associated with positive communication change for this group. Further investigation of its clinical effectiveness is warranted.
The Connectivity of Orofacial Systems
Authors: Estep Meredith E. , Barlow Steven M. 
Published: July 2009

Abstract
Acknowledging the dynamical properties of neural networks allows insight into the functional segregation and integration of cerebral areas. From a theoretical viewpoint, the complexity of neuronal interactions within a distributed system may reflect its capacity to rapidly process multimodal information and modulate context-sensitive neural activity to encode perception and adaptive behavior. This article highlights recent studies aimed at understanding the functionally flexible connectivity of the orofacial substrate.