bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of ultra intense laser pulse on the propagation of electron
plasma wave in relativistic and ponderomotive regime and particle
acceleration
Authors: KUMAR ATUL , GUPTA M.K. , SHARMA R.P.
Published: April 2008

In this paper, the effect of a relativistically intense Gaussian laser
pulse, on the propagation of electron plasma wave is studied. The
nonlinear effects considered here are the relativistic decrease of the
plasma frequency and the ponderomotive expelling of the electrons.
Modified coupled equations for laser and electron plasma wave are derived
from fluid equations. These coupled equations are solved analytically and
numerically to study the laser intensity in the plasma and the variation
of amplitude of the excited electron plasma wave. It is seen that the
effect of including the ponderomotive nonlinearity is significant on the
excitation of plasma wave. This should affect the number of energetic
electrons and their energy range on account of wave particle
interaction.
Smoothing and stochastic pulsation at high power laser-plasma interaction
Authors: HORA HEINRICH
Published: April 2008

Stochastic pulsation of laser-plasma interaction in the range of a few to dozens of picoseconds, due to standing wave produced density ripples, needs more attention than in the past, in view of the recent developments. This is important if nanosecond laser pulses produce a pre-compression that is a thousand times the solid state density of DT for fast ignition as well as for treatment of ps laser interaction. The following is an updated summary of these properties where the laser beam smoothing is essential. The use of smoothing is not only an empirical game with experiments for improving the interaction, but it is necessary to be aware of the mechanisms involved for understanding how the pulsation is overcome, and conclusions can be derived systematically for further improvements and control of the phenomena.
A pulsed power generator for x-pinch experiments
Authors: ZOU XIAOBING , LIU RUI , ZENG NAIGONG , HAN MIN , YUAN JIANQIANG , WANG XINXIN , ZHANG GUIXIN
Published: April 2008

A ∼500 kV/400 kA/100 ns pulsed power generator (PPG-I) for
x-pinch experiments was designed and constructed at Tsinghua University.
It is composed of a Marx generator, a combined pulse forming line (PFL), a
gas-filled V/N field distortion switch, a transfer line, and a
copper-sulphate resistive load for testing. The PPG-I implements a novel
design in lines that four pieces of waterline with impedance 5Ω in
parallel constitute a combined PFL with 1.25Ω, and incorporate each
other by a common self-break V/N switch on a matched 1.25Ω
transfer line. At the peak charging voltage of the PFL, the V/N switch
breaks down in multi-channel discharge mode, and electric energy is fed
into the testing load through the 1.25Ω transfer line. This article
presents the design and test of the PPG-I generator.
Genetic algorithms in spectroscopic diagnostics of hot dense
plasmas
Authors: ADÁMEK PETR , RENNER OLDRICH , DRSKA LADISLAV , ROSMEJ FRANK B. , WYART JEAN-FRANÇOIS
Published: April 2008

This paper will present a novel genetic-algorithm-based code (GASPED),
developed for the analysis of fine features (e.g., satellite structure and
line shifts) in X-ray spectra emitted by hot dense plasmas. The problem
dependent modification of standard genetic-algorithm concepts allows
efficient decomposition of spectra in concrete physical terms, such as
resonance and intercombination lines, dielectronic satellites, or
prospective nuclear transitions. Two examples of the code application
demonstrate the proposed approach. High resolution K-shell spectra emitted
from He- and Li-like Al ions immersed in dense, constrained-flow plasma
are decomposed into individual pseudo-Voigt components, by using
anticipatory theoretical knowledge of the satellite structure simulated by
the multilevel collisional-radiative code (MARIA). Line shifts of the
He-like resonance and intercombination line are deduced assuming the
aggregate plasma-induced shifts of the parent lines and their satellites.
The trend in the frequency shifts observed as a function of the variable
plasma parameters qualitatively follows the theoretical predictions. The
found variations of the exchange energy between the singlet and triplet
levels provide a new impact for the line shift theories. The second
example concerns the search for low-lying nuclear transitions in hot dense
laser-produced plasmas. The spectra of highly ionized Ta are decomposed by
combining the GASPED code with results of ab initio atomic data
calculations performed by the RELAC code. Upper limits for observation of
the controversial radiative decay of Ta nuclei at 6.238 eV are
estimated.
Fusion reactions and matter–antimatter annihilation for space
propulsion
Authors: DEUTSCH CLAUDE , TAHIR NAEEM A.
Published: April 2008

Magnetic confinement fusion (MCF) and inertial confinement fusion
(ICF) are critically contrasted in the context of far-distant travels
throughout solar system. Both are shown to potentially display superior
capabilities for vessel maneuvering at high speed, which are unmatched by
standard cryogenic propulsion (SCP). Costs constraints seem less demanding
than for ground-based power plants. Main issue is the highly problematic
takeoff from earth, in view of safety hazards concomitant to radioactive
spills in case of emergency. So, it is recommended to assemble the given
powered vessel at high earth altitude ∼ 700 km, above upper
atmosphere. Fusion propulsion is also compared to fission powered one,
which secures a factor of two improvement over SCP. As far a specific
impulse (s) is considered, one expects 500–3000 from fission and as
much as 104–105 from fusion through
deuterium–tritium (D-T). Next, we turn attention to the most
performing fusion reaction, i.e., proton–antiproton annihilation
with specific impulse ∼ 103–106 and
thrust–to–weight ratio ∼ 10−3–1.
Production and costs are timely reviewed. The latter could drop by four
orders of magnitude, which is possible with successful MCF or ICF.
Appropriate vessel designs will be presented for fusion as well as for
antimatter propulsion. In particular, ion compressed antimatter nuclear II
(ICAN-II) project to Mars in 30 days with fusion catalyzed by 140 ng of
antiprotons will be detailed (specific impulse ∼ 13500 s).
Trapping and acceleration of charged particles in Bessel beams
Authors: MELLADO V. H. , HACYAN S. , JÁUREGUI R.
Published: April 2008

We study the motion of a classical relativistic charged particle in
the electromagnetic field of a Bessel beam exhibiting vector optical
vortices, and show how its dynamical properties, such as linear and
angular momentum, are transmitted to the particle. The effects of
different polarizations are taken into account using transverse electric
and magnetic modes, and their superpositions. The constants of motion are
identified for the most general case. We report typical numerical results
for axial and radial motion for various configurations, with an estimate
of expected axial accelerations when transverse magnetic Bessel modes are
used. The Lorentz transformation properties of the field are used
throughout in order to simplify the calculations.
Workspace and singularity analysis of a 3-DOF planar parallel manipulator with actuation redundancy
Authors: Wang Jinsong , Wu Jun , Li Tiemin , Liu Xinjun
Published: April 2008

This paper deals with the position workspace, orientation workspace, and singularity of a 3-degree-of-freedom (DOF) planar parallel manipulator with actuation redundancy, which is created by introducing a redundant link with active actuator to a 3-DOF nonredundant parallel manipulator. Based on the kinematic analysis, the position workspace and orientation workspace of the redundantly actuated parallel manipulator and its corresponding nonredundant parallel manipulator are analyzed, respectively. In the singularity analysis phase, the relationship between the generalized input velocity and the generalized output velocity is researched on the basis of the theory of singular value decomposition. Then a method to investigate the singularity of parallel manipulators is presented, which is used to determine the singularity of the redundantly actuated parallel manipulator. In contrast to the corresponding nonredundant parallel manipulator, the redundant one has larger orientation workspace and less singular configurations. The redundantly actuated parallel manipulator is incorporated into a 4-DOF hybrid machine tool which also includes a feed worktable to demonstrate its applicability.
Hemodialysis for end-stage renal disease: A cost-effectiveness analysis of treatment options
Authors: Gonzalez-Perez Juan G. , Vale Luke , Stearns Sally C. , Wordsworth Sarah
Published: April 2008

Background: During 2001, over 32,000 patients in the United Kingdom received renal replacement therapy (RRT). Approximately half had a functioning transplant, with the remainder receiving dialysis therapy. The main form of dialysis is hemodialysis (HD), which is provided to 37.1 percent of the RRT population. HD is provided in three main settings: hospital (24.5 percent), satellite (10.9 percent), or home (1.7 percent). The objective of this study is to explore the cost-effectiveness of these different modalities.

Methods: By using clinical and cost data from a systematic review, a Markov model was developed to assess the costs and benefits of the three different modalities. The model included direct health service costs and quality-adjusted life years (QALYs). Sensitivity analyses were performed to assess the robustness of the results.

Results: Satellite HD has lower costs £46,000 and £62,050 at 5 and 10 years than home HD £47,660 and £63,540. The total effectiveness of home HD was slightly greater than for satellite HD, so the incremental cost per QALY of home versus satellite HD was modest at £6,665 at 5 years and £3,943 at 10 years. Both modalities dominated hospital HD.

Conclusions: Results from the study reveal that satellite HD was less costly than home HD, and home HD was less costly than hospital HD. The lack of robust data on the effectiveness and new dialysis equipment, which were not included in this review, throws some caution on these results. Nonetheless, the results are supportive of a shift from hospital HD to satellite and home HD.
Effectiveness and cost-effectiveness of initial combination therapy with interferon/peginterferon plus ribavirin in patients with chronic hepatitis C in Germany: A health technology assessment commissioned by the German Federal Ministry of Health and Social Security
Authors: Siebert Uwe , Sroczynski Gaby ,   on behalf of the German Hepatitis C Model (GEHMO) Group and the HTA Expert Panel on Hepatitis C
Published: April 2008

Objectives:The purpose of this health technology assessment (HTA), commissioned by the German Federal Ministry of Health and Social Security, was to systematically review the evidence for the effectiveness and cost-effectiveness of antiviral treatment (AVT) with interferon (INF) or peginterferon (PegIFN) in combination with ribavirin (RBV) in treatment-naïve patients with chronic hepatitis C (CHC) and to apply these data in the context of the German health-care system.

Methods:We performed a systematic literature search on effectiveness and cost-effectiveness of AVT and summarized results using meta-analysis and evidence tables. We applied the German Hepatitis C Model (GEHMO), a decision-analytic Markov model, to determine long-term clinical effectiveness, costs, and incremental cost-effectiveness ratios (ICER) of the examined treatment strategies. Model parameters were derived from German databases, published international randomized clinical trials (RCT), and a Cochrane Review.

Results:Overall, nine RCTs, two HTA reports, one Cochrane review, two meta-analyses, and seven economic evaluations met the inclusion criteria. These studies indicate that PegIFN+RBV achieved the highest sustained virological response rates (SVR) (54–61 percent), followed by IFN+RBV (38–54 percent) and IFN monotherapy (11–21 percent). Based on our meta-analysis, PegIFN+RBV reduced cases without SVR by 17 percent compared with INF+RBV. International cost-effectiveness studies indicate that INF+RBV is cost-effective when compared with INF monotherapy. For PegIFN+RBV, our decision analysis yielded an ICER of €9,800 per quality-adjusted life-year gained.

Conclusions:This HTA suggests that initial combination therapy prolongs life, improves quality of life, and is cost-effective in patients with CHC. Peginterferon plus ribavirin is the most effective and efficient treatment among the examined options. However, because not all chronic hepatitis C patients will develop progressive liver disease, a thorough assessment of the eligibility and appropriateness of treatment with combination therapy must be performed in each individual patient.
Determinants of computed tomography and magnetic resonance imaging utilization in Taiwan
Authors: Kung Pei-Tseng , Tsai Wen-Chen , Yaung Chih-Liang , Liao Kai-Ping
Published: April 2008

Objectives:Magnetic resonance imaging (MRI) and computerized tomography (CT) scanners are high-tech equipment with the highest utilizations and expenditures in Taiwan. This study investigates the factors that affect MRI and CT utilization, such as whether supply-side factors have more impact than demand-side factors, and the effect of utilization control policies.

Methods:This study used the nationwide CT and MRI claim data for the years 1998 to 2001 from the Bureau of National Health Insurance (BNHI) in Taiwan. Multiple regression analysis was the statistical method used to determine the relative factors that influence CT and MRI utilization.

Results:CT : population ratio, hospital-based physician : population ratio, female ratio, pediatric (≤14 years) : population ratio, and family income significantly influenced CT utilization. MRI : population ratio and hospital-based physician : population ratio, female ratio, and family income significantly influenced MRI utilization. However, the proportion of the aged (≥65 years of age) did not significantly influence CT or MRI utilization after controlling for other factors. The rates of CT and MRI utilization for the outpatient and inpatient settings and the repeated uses of CT or MRI have decreased significantly after a utilization review was implemented by BNHI, which suggests that CT and MRI have been overused.

Conclusions:Increases in supply-side factors significantly increase CT/MRI utilization, and supply-side factors impact CT/MRI utilization more than demand-side factors. The results show that the utilization instant report policy effectively decreases repeated uses of CT/MRI.
Validity of utilities of patients with esophageal cancer
Authors: Stalmeier Peep F. M. , de Boer Angela G. E. M. , Sprangers Mirjam A. G. , de Haes Hanneke C. J. M. , van Lanschot Jan J. B.
Published: April 2008

Objectives: The convergent validity between utility assessment methods was assessed.

Methods: Investigated were patients with esophageal cancer treated surgically with curative intent. Patients were interviewed in a period from 3 to 12 months after surgical resection. Patients evaluated their actual health and seven other states. Visual analogue scale (VAS) and standard gamble (SG) utilities were obtained for the health states in an interview. Patients also indicated whether or not they preferred death to living in a health state (worse than dead [WTD] preferences).

Results: Fifty patients completed the interview. Convergent validity was excellent at the aggregate and individual level. However, the relation between VAS and SG differed strongly across individuals. On a scale from 0 (dead) to 100 (perfect health), SG scores were lower for patients with WTD preferences (mean difference d=35; p=.002); however, VAS scores did not vary by WTD preferences.

Conclusions: In general, there is good agreement between VAS and SG measures, although patients disagree about how the VAS and SG are related. The standard gamble varied by WTD preferences, however, the VAS did not.
Can electronic routine data act as a surrogate for patient-assessed outcome measures?
Authors: Hutchings Hayley A. , Cheung Wai-Yee , Williams John G. , Cohen David , Longo Mirella F. , Russell Ian
Published: April 2008

Objectives:There has been a rapid growth in the use of patient-assessed outcomes (PAOs) that are measured in the assessment of health technologies. The process of collection of such measures can be costly, and there may be problems associated with the ability of the patient to complete them. The use of electronically stored routine data may reduce costs and overcome the problems associated with patient completion. The feasibility of using routine data surrogates for the UK Inflammatory Bowel Disease Questionnaire (UKIBDQ) and the Short Form 36 (SF-36) was examined.

Methods:Clinical terms and codes for the UKIBDQ and SF-36 questions were identified, and data from electronic routine sources were sought on patients participating in a randomized controlled trial. The presence or absence of relevant symptoms was used to generate surrogate scores, which were compared with the original scores.

Results:Most questions in the UKIBDQ and SF-36 were codable but only one third of the terms were recorded routinely in electronic form. The surrogate total IBDQ score had reasonable reliability (Kuder–Richardson coefficient = 0.51), but this reliability could not be determined for the SF-36. Intraclass correlations between routine and designed data were poor to weak.

Conclusions:Although electronic routine data sources had the capacity to develop surrogate measures for patient assessed outcomes, there was evidence of wide underutilization of coding systems leading to an underreporting of symptoms. This finding is consistent with previous literature where only poor correlations were illustrated between patient assessed outcomes and surrogate scoring of symptoms.
Randomized controlled trial to evaluate the clinical- and cost-effectiveness of Hickman line insertions in adult cancer patients by nurses
Authors: Boland A. , Haycox A. , Bagust A. , Fitzsimmons L.
Published: April 2008

Objectives: This study examined the
clinical- and cost-effectiveness of image-guided Hickman line insertions
versus blind Hickman line insertions undertaken by nurses in adult
cancer patients.
Systematic review of isolation policies in the hospital management of methicillinresistant Staphylococcus aureus: A review of the literature with epidemiological and economic modeling
Authors: Cooper B. S. , Stone S. P. , Kibbler C. C. , Cookson B. D. , Roberts J. A. , Medley G. F. , Duckworth G. J. , Lai R. , Ebrahim S.
Published: April 2008

Objectives: This study reviewed the
evidence for the effectiveness of different isolation policies and
screening practices in reducing the incidence of methicillin-resistant
Staphylococcus aureus (MRSA) colonization and infection in
hospital inpatients in an effort to develop transmission models to study
the effectiveness and cost-effectiveness of isolation policies in
controlling MRSA.
Clinical practice guidelines and organizational adaptation: A framework for analyzing economic effects
Authors: Schneider John E. , Peterson N. Andrew , Vaughn Thomas E. , Mooss Eric N. , Doebbeling Bradley N.
Published: April 2008

Objectives:The overall objective of this article was to review the theoretical and conceptual dimensions of how the implementation of clinical practice guidelines (CPGs) is likely to affect treatment costs.

Methods:An important limitation of the extant literature on the cost effects of CPGs is that the main focus has been on clinical adaptation. We submit that the process innovation aspects of CPGs require changes in both clinical and organizational dimensions. We identify five organizational factors that are likely to affect the relationship between CPGs and total treatment costs: implementation, coordination, learning, human resources, and information. We review the literature supporting each of these factors.

Results:The net organizational effects of CPGs on costs depends on whether the cost-reducing properties of coordination, learning, and human resource management offset potential cost increases due to implementation and information management.

Conclusions:Studies of the cost effects of clinical practice guidelines should attempt to measure, to the extent possible, the effects of each of these clinical and organizational factors.
Cost-effectiveness of a graded exercise therapy program for patients with chronic shoulder complaints
Authors: Geraets Jacques J. X. R. , Goossens Mariëlle E. J. B. , de Bruijn Camiel P. C. , de Groot Imelda J. M. , Köke Albère J. S. , Pelt Rob A. G. B. , van der Heijden Geert , Dinant Geert-Jan , van den Heuvel Wim J. A.
Published: April 2008

Objectives:The present study evaluated the cost-effectiveness of a behavioral graded exercise therapy (GET) program compared with usual care (UC) in terms of the performance of daily activities by patients with chronic shoulder complaints in primary care.

Methods:A total of 176 patients were randomly assigned either to GET (n=87) or to UC (n=89). Clinical outcomes (main complaints, shoulder disability [SDQ] and generic health-related quality of life [EQ-5D], and costs [intervention costs, direct health care costs, direct non–health-related costs, and indirect costs]) were assessed during the 12-week treatment period and at 52 weeks of follow-up.

Results:Results showed that GET was more effective than UC in restoring daily activities as assessed by the main complaints instrument after the 12-week treatment period (p=.049; mean difference, 7.5; confidence interval [CI], 0.0–15.0). These effects lasted for at least 52 weeks (p=.025; mean difference 9.2; CI, 1.2–17.3). No statistically significant differences were found on the SDQ or EQ5D. GET significantly reduced direct health care costs (p=.000) and direct non–health care costs (p=.029). Nevertheless, total costs during the 1-year follow-up period were significantly higher (p=.001; GET=€530 versus UC=€377) due to the higher costs of the intervention. Incremental cost-effectiveness ratios for the main complaints (0–100), SDQ (0–100), and EQ-5D (−1.0–1.0) were €17, €74, and €5,278 per unit of improvement, respectively.

Conclusions:GET proved to be more effective in the short- and long-term and reduces direct health care costs and direct non–health care costs but is associated with higher costs of the intervention itself.
Cost-effectiveness of drotrecogin alfa (activated) in the treatment of severe sepsis with multiple organ failure
Authors: França Lionel Riou , Launois Robert , Le Lay Katell , Aegerter Philippe , Bouhassira Myriam , Meshaka Patrick , Guidet Bertrand
Published: April 2008

Objectives:The aim of this study was to estimate the expected cost and clinical benefits associated with the use of drotrecogin alfa (activated) (Xigris; Eli Lilly and Company; Indianapolis, IN) in the French hospital setting.

Methods:The recombinant human activated PROtein C Worldwide Evaluation in Severe Sepsis (PROWESS) study results (1,271 patients with multiple organ failure) were adjusted to 9,948 hospital stays from a database of Parisian area intensive-care units (ICUs)—the CubRea (Intensive Care Database User Group) database. The analysis features a decision tree with a probabilistic sensitivity analysis.

Results:The cost per life year gained (LYG) of drotrecogin treatment for severe sepsis with multiple organ failure (European indication) was estimated to be $11,812. At the hospital level, the drug is expected to induce an additional cost of $7,545 per treated patient. The incremental cost-effectiveness ratio ranges from $7,873 per LYG for patients receiving three organ supports during ICU stay to $17,704 per LYG for patients receiving less than two organ supports.

Conclusions:Drotrecogin alfa (activated) is cost-effective in the treatment of severe sepsis with multiple organ failure when added to best standard care. The cost-effectiveness of the drug increases with baseline disease severity, but it remains cost-effective for all patients when used in compliance with the European approved indication.
Value of magnetic resonance cholangiopancreatography in the diagnosis of biliary abnormalities in postcholecystectomy patients: A probabilistic cost-effectiveness analysis of diagnostic strategies
Authors: Howard Kirsten , Lord Sarah J. , Speer Anthony , Gibson Robert N. , Padbury Robert , Kearney Brendon
Published: April 2008

Background:Endoscopic retrograde cholangiopancreatography (ERCP) is considered the gold standard for imaging of the biliary tract but is associated with complications. Less invasive imaging techniques, such as magnetic resonance cholangiopancreatography (MRCP), have a much lower complication rate. The accuracy of MRCP is comparable to that of ERCP, and MRCP may be more effective and cost-effective, particularly in cases for which the suspected prevalence of disease is low and further intervention can be avoided. A model was constructed to compare the effectiveness and cost-effectiveness of MRCP and ERCP in patients with a previous history of cholecystectomy, presenting with abdominal pain and/or abnormal liver function tests.

Methods:Diagnostic accuracy estimates came from a systematic review of MRCP. A decision analytic model was constructed to represent the diagnostic and treatment pathway of this patient group. The model compared the following two diagnostic strategies: (i) MRCP followed with ERCP if positive, and then management based on ERCP; and (ii) ERCP only. Deterministic and probabilistic analyses were used to assess the likelihood of MRCP being cost-effective. Sensitivity analyses examined the impact of prior probabilities of common bile duct stones (CBDS) and test performance characteristics. The outcomes considered were costs, quality-adjusted life years (QALYs), and cost per additional QALY.

Results:The deterministic analysis indicated that MRCP was dominant over ERCP. At prior probabilities of CBDS, less than 60 percent MRCP was the less costly initial diagnostic test; above this threshold, ERCP was less costly. Similarly, at probabilities of CBDS less than 68 percent, MRCP was also the more effective strategy (generated more QALYs). Above this threshold, ERCP became the more effective strategy. Probabilistic sensitivity analyses indicated that, in this patient group for which there is a low to moderate probability of CBDS, there was a 59 percent likelihood that MRCP was cost-saving, an 83 percent chance that MRCP was more effective with a higher quality adjusted survival, and an 83 percent chance that MRCP had a cost-effectiveness ratio more favorable than $50,000 per QALY gained.

Conclusions:Costs and cost-effectiveness are dependent upon the prior probability of CBDS. However, probabilistic analysis indicated that, with a high degree of certainty, MRCP was the more effective and cost-effective initial test in postcholecystectomy patients with a low to moderate probability of CBDS.
Cost of an informatics-based diabetes management program
Authors: Blanchfield Bonnie B. , Grant Richard W. , Estey Greg A. , Chueh Henry C. , Gazelle G. Scott , Meigs James B.
Published: April 2008

Objectives: The relatively high cost of information technology systems may be a barrier to hospitals thinking of adopting this technology. The experiences of early adopters may facilitate decision making for hospitals less able to risk their limited resources. This study identifies the costs to design, develop, implement, and operate an innovative informatics-based registry and disease management system (POPMAN) to manage type 2 diabetes in a primary care setting.

Methods: The various cost components of POPMAN were systematically identified and collected.

Results: POPMAN cost $450,000 to develop and operate over 3.5 years (1999–2003). Approximately $250,000 of these costs are one-time expenditures or sunk costs. Annual operating costs are expected to range from $90,000 to $110,000 translating to approximately $90 per patient for a 1,200 patient registry.

Conclusions: The cost of POPMAN is comparable to the costs of other quality-improving interventions for patients with diabetes. Modifications to POPMAN for adaptation to other chronic diseases or to interface with new electronic medical record systems will require additional investment but should not be as high as initial development costs. POPMAN provides a means of tracking progress against negotiated quality targets, allowing hospitals to negotiate pay for performance incentives with insurers that may exceed the annual operating cost of POPMAN. As a result, the quality of care of patients with diabetes through use of POPMAN could be improved at a minimal net cost to hospitals.
CONSISTENT COVARIANCE MATRIX ESTIMATION FOR LINEAR PROCESSES
Authors: Jansson Michael
Published: April 2008

Consistency of kernel estimators of the long-run covariance
matrix of a linear process is established under weak moment
and memory conditions. In addition, it is pointed out that some
existing consistency proofs are in error as they stand.
LANGUAGES FOR SPECIFIC PURPOSES
Authors: Swales John M.
Published: April 2008

Thirty-five years ago, three leading British linguists published a landmark volume entitled The linguistic sciences and language teaching (Halliday, McIntosh and Strevens 1964). The careful wording of the title of this book was something of a clarion call; in effect, the authors promised to usher in a Brave New World of a stronger descriptive base for pedagogical materials.
SECOND LANGUAGE ACQUISITION AND APPLIED LINGUISTICS
Authors: Larsen-Freeman Diane
Published: April 2008

Just as applied linguistics (AL) may be said to be an emerging discipline, so too is one of its sub-fields, second language acquisition (SLA). The parallelism may not be surprising; after all, a difference of only about twenty years separates the points at which the two were identified as autonomous fields of inquiry. Then, too, the two share central defining concepts. AL draws on multidisciplinary theoretical and empirical perspectives to address real-world issues and problems in which language is central (Brumfit 1997). SLA draws on multidisciplinary theoretical and empirical perspectives to address the specific issue of how people acquire a second language and the specific problem of why everyone does not do so successfully. Furthermore, the two share something else: At this juncture in the evolution of AL and SLA, both are grappling with fundamental definitional issues, ones even extending to the nature of language itself. (See Larsen-Freeman 1997a for how this is true of AL.) Should AL and SLA deal successfully with these challenges, both will have much to contribute in the decade to come. Should they instead succumb to internecine feuding and fragmentation, the future will not be as bright.
FRENCH IMMERSION RESEARCH IN CANADA: RECENT CONTRIBUTIONS TO SLA AND APPLIED LINGUISTICS
Authors: Swain Merrill
Published: April 2008

This review chapter addresses two questions: What has the recent research conducted in French immersion programs in Canada contributed to our understanding of second language acquisition (SLA)? What has it contributed to the broader field of applied linguistics? In this chapter, I also consider briefly what the research contributions of the coming decade might be and discuss some of the obstacles that may be faced in Canada in continuing to conduct research concerned with French immersion education.
A CRITICAL REVIEW OF THE CRITICAL PERIOD RESEARCH
Authors: Scovel Thomas
Published: April 2008

Two decades of international research in applied linguistics provides a large number and variety of topics from which to choose for this special anniversary edition, but certainly one of the most significant among these choices is the critical period hypothesis (CPH). Few topics in applied linguistics have continued to captivate the interests of researchers and practitioners so intensively and for such a long period of time as the CPH. Indeed, one could easily go back to reviewing three, not two decades of sustained research and continuous interest in this topic (Lenneberg 1967, Scovel 1969). If number and diversity of publications is indicative, the CPH has engendered even more interest and controversy now than in any previous decade. Why is this so?
PSYCHOLINGUISTICS IN APPLIED LINGUISTICS: TRENDS AND PERSPECTIVES
Authors: de Bot Kees
Published: April 2008

This article addresses the relationship between two major terms, psycho-linguistics and applied linguistics, and in the process, explores key issues in multilingual processing. A straightforward definition of psycholinguistics is provided by Kess (1991:1): ‘The field of study concerned with psychological aspects of language studies.’ In the last decade, the definition has become more restricted, leaving out more social-psychological aspects like the study of attitudes in language use. Here, psycholinguistics will be further restricted to the study of processes of language production and perception (as opposed to acquisition and attrition).
COGNITIVE APPROACHES TO SLA
Authors: Ellis Nick
Published: April 2008

Getting to know a second language is an act of cognition par excellence. Yet 'Cognitive Approaches to SLA' implies something more than the general research enterprise of SLA. It highlights the goals of cognitive psychologists who search for explanations of second language cognition in terms of mental representations and information processing. It places SLA within the broader remit of cognitive scientists, who—influenced by Marr (1982) to seek understanding at all three levels of function, algorithm, and hardware—work in collaborations involving cognitive psychology, linguistics, epistemology, computer science, artificial intelligence, connectionism, and the neurosciences. It implies the empiricism of cognitive psychology, searching for truths about the world through observation and experimentation and, at times, the rationalism of cognitive scientists who theorize through the construction of formal systems such as those in mathematics, logic, or computational simulation. Much of the research is purely theoretical, but, as in applied cognitive psychology, pure theory can often spin off into important applications, and applied research using longitudinal or training designs in field situations can often advance theory.
INPUT-BASED APPROACHES TO TEACHING GRAMMAR: A REVIEW OF CLASSROOM-ORIENTED RESEARCH
Authors: Ellis Rod
Published: April 2008

There is now a substantial body of research that has investigated the role of form-focused instruction in assisting learners to learn the grammar of a second language (L2). Recent comprehensive surveys of this research have been provided by N. Ellis (1995), R. Ellis (1990; 1994; 1997), Larsen-Freeman and Long (1991), Long (1988), Spada (1997), and Williams (1995a). However, it is becoming increasingly difficult to draw clear conclusions given the sheer amount of research now available, the problems of comparing results across studies, and the interactivity of the variables involved. Spada, for example, identifies seven questions that the research has addressed but acknowledges that “we do not yet have clear answers to any of these questions” (p. 74). One way of achieving a clearer understanding of how form-focused instruction contributes to acquisition might be to examine in detail studies that have investigated the effect of specific instructional options. This article will follow such an approach by examining one particular option–input–based grammar teaching.
LANGUAGE AND MEDICINE
Authors: Hydén Lars–Christer , Mishler Elliot G.
Published: April 2008

Research on the forms and functions of language in medical practice and training has expanded rapidly during the past two decades, a development marked by diversity in theoretical perspectives and methods brought to bear on a variety of problems. Although we label the area as “language and medicine,” it includes other health professionals and nonclinical settings. Our discussion is organized under four headings that we believe represent primary topics and domains of interest among investigators as well as the variability within the field: speaking to patients, speaking with patients, speaking about patients, and speaking by patients. A few exemplar studies will be cited in each section and the contributions and limitations of approaches in each topic area will be noted.
VALIDITY IN LANGUAGE ASSESSMENT
Authors: Chapelle Carol A.
Published: April 2008

All previous papers on language assessment in the Annual Review of Applied Linguistics make explicit reference to validity. These reviews, like other work on language testing, use the term to refer to the quality or acceptability of a test. Beneath the apparent stability and clarity of the term, however, its meaning and scope have shifted over the past years. Given the significance of changes in the conception of validity, the time is ideal to probe its meaning for language assessment.
Monitoring the Stable at the Pasteur Institute
Authors: Simon Jonathan
Published: April 2008

Argument

Diphtheria serum production in France was dominated by the Pasteur Institute, which equipped a facility at Garches to produce the antitoxin on a large scale. This article treats the background to the founding of this facility, as well as its day-to-day functioning around 1900. The treatment integrates an examination of the practical undertaking of serum production by the Pasteur Institute with an analysis of the popular perception of the Institute and the mixed financing of the whole venture. We particularly emphasize the “industrial” features of this manufacturing process that involved living units of production, showing how bioassays influenced the destiny of the animals producing the serum. Finally, we argue that this monitoring of the horses, seen as serum-producing units, also provided information on the diseases the sera were intended to treat.
The Administrative Stabilization of Vaccines: Regulating the Diphtheria Antitoxin in France and Germany, 1894–1900
Authors: Hess Volker
Published: April 2008

Argument

It is well known that the development of a diphtheria anti-toxin serum evolved in a competitive race between two groups of researchers, one affiliated with Emil Behring in Berlin and Marburg, and another affiliated with Émile Roux in Paris. Proceeding on the basis of different theoretical assumptions and experimental practices, the two groups developed a therapeutic serum almost simultaneously. But the standardized substance they developed took on very different forms in the two countries. In Germany the new serum was marketed in the private sphere and subjected to state regulations, becoming a kind of prototype of industrial medications. In France, however, the same substance was marketed as a gift of science to humanity and distributed through the communal health care system. This article demonstrates how a new medication emerged from the efforts to produce, market, regulate, distribute, and apply it in the two respective countries. It attributes the difference to the negotiations between the respective actors (scientists, industrialists, politicians, officers, and the public) and institutions (firms, academies, private and public institutes, legislative bodies, professional corporations). I develop this argument on three different levels: First, I stress the importance of the institutional foundations of serum production; second, I illustrate the decisive role played by existing “ways of regulating” in the rapid development of new legal statutes; and third, I describe the consequences that flowed from the respective administrative organization of marketing and dissemination. In sum, I explore how an experimental object was transformed into an object of the public health system and stabilized by administrative means.
The Dynamics ofWertbestimmung
Authors: Hüntelmann Axel C.
Published: April 2008

Argument

The procedure ofWertbestimmungplayed a vital role in the implementation of serum therapy and the standardization of mass-produced pharmaceuticals. In fin-de-siècle Germany, a legal framework was put in place to guarantee serum quality and safety and to minimize any associated public health risks. Because the sera were biological remedies, it was difficult to produce them in uniform quality and the procedure ofWertbestimmung, i.e. determining the potency of the serum based on an objective and comparable value, was extremely complex. Various agents such as bacteria cultures, serum hosts, or test animals had to be regulated. In the years after 1895, numerous efforts to stabilize the procedures ofWertbestimmungwere undertaken by serum producers and members of the state-run survey institute responsible for overseeing serum production. Despite efforts to stabilize the framework and to generate a reliable reference system, the framework's environment and agents were in constant flux: new producers entered the market and procedures were expanded to include other biologicals as well. The article describes the dynamics involved in the sustained efforts to maintain a stable framework in the face of constant alterations between 1895 and the 1920s.
COMPOUND RANDOM VARIABLES
Authors: Peköz Erol , Ross Sheldon M.
Published: April 2008

We give a probabilistic proof of an identity concerning the
expectation of an arbitrary function of a compound random variable and
then use this identity to obtain recursive formulas for the probability
mass function of compound random variables when the compounding
distribution is Poisson, binomial, negative binomial random,
hypergeometric, logarithmic, or negative hypergeometric. We then show
how to use simulation to efficiently estimate both the probability that
a positive compound random variable is greater than a specified
constant and the expected amount by which it exceeds that constant.
ON/OFF STORAGE SYSTEMS WITH STATE-DEPENDENT INPUT, OUTPUT, AND
SWITCHING RATES
Authors: Boxma Onno , Kaspi Haya , Kella Offer , Perry David
Published: April 2008

We consider a storage model that can be on or off. When on, the
content increases at some state-dependent rate and the system can
switch to the off state at a state-dependent rate as well. When off,
the content decreases at some state-dependent rate (unless it is at
zero) and the system can switch to the on position at a state-dependent
rate. This process is a special case of a piecewise deterministic
Markov process. We identify the stationary distribution and conditions
for its existence and uniqueness.
A LOADING-DEPENDENT MODEL OF PROBABILISTIC CASCADING FAILURE
Authors: Dobson Ian , Carreras Benjamin A. , Newman David E.
Published: April 2008

We propose an analytically tractable model of loading-dependent cascading failure that captures some of the salient features of large blackouts of electric power transmission systems. This leads to a new application and derivation of the quasibinomial distribution and its generalization to a saturating form with an extended parameter range. The saturating quasibinomial distribution of the number of failed components has a power-law region at a critical loading and a significant probability of total failure at higher loadings.
OPTIMAL EXIT FROM A DETERIORATING PROJECT WITH NOISY RETURNS
Authors: Ryan Reade , Lippman Steven A.
Published: April 2008

We consider the problem of determining when to exit an investment
whose cumulative return follows a Brownian motion with drift μ and
volatility σ2. After an unobserved exponential amount of
time, the drift drops from μH > 0 to
μL < 0. Using results from stochastic
differential equations, we are able to show that it is optimal to exit the
first time the posterior probability of being in the low state falls to
p*, where the value of p* is given implicitly. We effect
a complete comparative statics analysis; one surprising result is that a
decrease in μL is beneficial when
|μL| is large.
SOJOURN TIMES IN THE M/G/1 FB QUEUE WITH
LIGHT-TAILED SERVICE TIMES
Authors: Mandjes M. , Nuyens M.
Published: April 2008

The asymptotic decay rate of the sojourn time of a customer in the
stationary M/G/1 queue under the
foreground–background (FB) service discipline is studied. The FB
discipline gives service to those customers that have received the least
service so far. We prove that for light-tailed service times, the decay
rate of the sojourn time is equal to the decay rate of the busy period. It
is shown that FB minimizes the decay rate in the class of work-conserving
disciplines.
EXPLOITING THE WAITING TIME PARADOX: APPLICATIONS OF THE
SIZE-BIASING TRANSFORMATION
Authors: Brown Mark
Published: April 2008

We consider the transformation T that takes a distribution
F into the distribution of the length of the interval covering a
fixed point in the stationary renewal process corresponding to F.
This transformation has been referred to as size-biasing, length-biasing,
the renewal length transformation, and the stationary lifetime operator.
We review and develop properties of this transformation and apply it to
diverse areas.
THE OPTIMAL CONTROL OF A GENERAL TANDEM QUEUE
Authors: Weichbold Josef , Schiefermayr Klaus
Published: April 2008

We consider a scheduling problem with two interconnected queues and two flexible servers. It is assumed that all jobs are present at the beginning and that there are no further arrivals to the system at any time. For each job, there are waiting costs per unit of time until the job leaves the system. A job of queue 1, after being served, joins queue 2 with probabilitypand leaves the system with probability 1 −p. The objective is how to allocate the two servers to the queues such that the expected total holding costs until the system is empty are minimized. We give a sufficient condition such that for any number of jobs in queue 1 and queue 2, it is optimal to allocate both servers to queue 1 (resp. queue 2).
STOCHASTIC ORDERINGS BETWEEN p-SPACINGS OF GENERALIZED
ORDER STATISTICS FROM TWO SAMPLES
Authors: Hu Taizhong , Zhuang Weiwei
Published: April 2008

The concept of generalized order statistics was introduced as a
unified approach to a variety of models of ordered random variables. The
purpose of this article is to investigate conditions on the distributions
and the parameters on which the generalized order statistics are based to
establish the likelihood ratio ordering of general p-spacings and
the hazard rate and the dispersive orderings of (normalizing) simple
spacings from two samples. We thus strengthen and complement some results
in Franco, Ruiz, and Ruiz [7] and
Belzunce, Mercader, and Ruiz [5]. This
article is a continuation of Hu and Zhuang [10].
DEPENDENCE ORDERING FOR QUEUING NETWORKS WITH BREAKDOWN AND
REPAIR
Authors: Daduna Hans , Kulik Rafał , Sauer Cornelia , Szekli Ryszard
Published: April 2008

In this article we introduce isotone differences stochastic ordering
of Markov processes on lattice ordered state spaces as a device to compare
the internal dependencies of two such processes. We derive a
characterization in terms of intensity matrices. This enables us to
compare the internal dependency structure of different degradable Jackson
networks in which the nodes are subject to random breakdowns and repairs.
We show that the performance behavior and the availability of such
networks can be compared.