bluuebunny/crossref_metadata_2025 huggingface dataset:
Direct-indirect mixture implosion in heavy ion fusion
Authors: SOMEYA TETSUO , MIYAZAWA KENTAROU , KIKUCHI TAKASHI , KAWATA SHIGEO
Published: April 2008

In order to realize an effective implosion, the beam illumination
non-uniformity and implosion non-uniformity must be suppressed to less
than a few percent. In this paper, a direct-indirect mixture implosion
mode is proposed and discussed in heavy ion beam (HIB) inertial
confinement fusion (HIF) in order to release sufficient fusion energy in a
robust manner. On the other hand, the HIB illumination non-uniformity
depends strongly on a target displacement (dz) in a reactor. In a
direct-driven implosion mode dz of ∼20 μm was tolerance
and in an indirect-implosion mode dz of ∼100 μm was
allowable. In the direct-indirect mixture mode target, a low-density foam
layer is inserted, and radiation is confined in the foam layer. In the
foam layer the radiation transport is expected in the lateral direction
for the HIB illumination non-uniformity smoothing. Two-dimensional
implosion simulations are performed and show that the HIB illumination
non-uniformity is well smoothed. The simulation results present that a
large pellet displacement of ∼300 μm is tolerable in order to
obtain sufficient fusion energy in HIF.
Warm-dense-matter studies using pulse-powered wire discharges in
water
Authors: SASAKI TORU , YANO YUURI , NAKAJIMA MITSUO , KAWAMURA TOHRU , HORIOKA KAZUHIKO
Published: April 2008

Dense plasmas are produced using exploding wire discharges in water.
Evolutions of radius, electrical conductivity, temperature of plasma and a
shock wave in water accompanied with the explosion, are measured.
Conductivities of aluminum, copper, and tungsten are compared with
theoretical ones. To evaluate the equation of state, trajectories of the
shock wave and the plasma boundary are compared with numerical
calculations. Results show that the hydrodynamic behaviors are sensitive
to the models of equation of state. Controllability of warm dense state in
density-temperature diagram is discussed from the voltage-current
characteristics of the wire discharges.
The k-L turbulence model for describing buoyancy-driven fluid
instabilities
Authors: CHIRAVALLE VINCENT P.
Published: April 2008

The k-L turbulence model, where k is the
turbulent kinetic energy and L represents the turbulent eddy
scale length, is a two-equation turbulence model that has been proposed to
simulate turbulence induced by Rayleigh-Taylor (RT) and Richtmyer Meshkov
(RM) instabilities, which play an important role in the implosions of
inertial confinement fusion (ICF) capsule targets. There are three free
parameters in the k-L model, and in this paper, I
calibrate them independently by comparing with RT and RM data from the
linear electric motor (LEM) experiments together with classical
Kelvin-Helmoholtz (KH) data. To perform this calibration, I numerically
solved the equations of one-dimensional (1D) Lagrangian hydrodynamics, in
a manner similar to that of contemporary ICF codes, together with the
k-L turbulence model. With the three free parameters
determined, I show that the k-L model is successful in
describing both shear-driven and buoyancy-driven instabilities, capturing
the experimentally observed separation between bubbles and spikes at high
Atwood number for the RT case, as well as the temporal mix width recorded
in RM shock tube experiments.
Editorial from the Editor in Chief
Authors: HOFFMANN DIETER H.H.
Published: April 2008

Since 2003, the journal of Laser and Particle Beams no longer
publishes conference proceedings. Even of those conferences where the
topics are very closely related to the research fields discussed in this
journal. Authors are instead encouraged to submit a regular paper dealing
with the topic presented during a conference. The advantage for authors is
that there is no page limit as long as the paper passes the peer review
process. The discussion of the presented research during the conference
helps reviewers to evaluate the quality of the paper and this usually
leads to a speedy publication process. Every year in June, the ISI Web of
Knowledge releases the Journal Citation Reports. The publication policy
adopted by the Laser and Particle Beams editorial board was
obviously quite successful since we experienced a substantial increase in
the impact factor and in the immediacy index. Thus the Journal Citation
Report lists Laser and Particle Beams now as a leading journal in
the field of applied physics. This is an opportunity to thank authors for
their high quality contributions to this journal. The publisher and the
editorial board will try to continue to improve the service to readers and
authors during the upcoming years.
Two-photon group radiation transfer study in low-density foam
cylinder
Authors: XU YAN , JIANG SHAOENG , LAI DONGXIAN , PEI WENBING , DING YONGKUN , CHANG TIEQIANG , LAN KE , LI SHUANGGUI , FENG TINGGUI
Published: April 2008

Radiation transfer in low-density foam is influenced by the external
radiation field which impacts on the foam when the size of plasma created
in laboratory is not large to be opatical thick. The radiation transfers
of different photon groups are sensitive probes of the conditions of the
medium through which they propagate. The temporal behavior of photon
groups to which the plasma is optical thin is quite different from that of
photon groups to which the plasma is optical thick. The breakout times of
different photon groups through the foam are distinguishable different in
experiment when we measures them at the end of foam. The multi-group
supersonic radiation transfer behavior in low-density foam is studied both
by multi-group transfer numerical simulation and experiments. Two
characteristic photon groups are chosen to do experimental research on the
multi-group transfer behavior in low-density CH foam. A time-resolved
chromatic streaked X-ray spectrometer measure the breakout of the two
photon group from the far end of the foam cylinder. The distinguishable
transfer time delay between two groups is observed.
Laser amplification by electric pulse power
Authors: WINTERBERG F.
Published: April 2008

It is proposed that it is possible to amplify the energy of a pulsed
laser beam by imploding it inside a capillary metallic liner. If imploded
with megaampere currents by the pinch effect, implosion velocities up to
∼3 × 108 cm/s can be reached, imploding a few cm
long liner with an inner radius of 2 × 10−3 cm in
about ∼10−10 s. If the liner radius can be imploded
by 30-fold, the laser pulse would in the absence of absorption losses into
the linear wall be amplified 1000-fold. Because the amplification is
through the conversion from longer to shorter wave lengths, the concept
offers the prospect of intense short wave length laser pulses in the far
ultraviolet and soft X-ray domain. Apart from the direct drive laser beam
compression by the pinch effect, an alternative indirect drive through the
conversion of the electric pulse power into soft X-rays is possible as
well. The limitations of this concept are the absorption losses into the
liner wall, and ways to overcome these losses are presented. The most
important application of the proposed laser amplification scheme might be
for the fast ignition of various inertial confinement fusion schemes. An
integrated fast ignition inertial confinement fusion concept using the
indirect drive is also presented.
Astrophysical radiative shocks: From modeling to laboratory
experiments
Authors: GONZÁLEZ MATTHIAS , STEHLÉ CHANTAL , AUDIT EDOUARD , BUSQUET MICHEL , RUS BEDRICH , THAIS FRÉDÉRIC , ACEF OUALI , BARROSO PATRICE , BAR-SHALOM ABRAHAM , BAUDUIN DANIEL , KOZLOVÀ MICHAELA , LERY THIBAUT , MADOURI ALI , MOCEK TOMAS , POLAN JIRI
Published: April 2008

Radiative shock waves are observed around astronomical objects in a
wide variety of environments, for example, they herald the birth of stars
and sometimes their death. Such shocks can also be created in the
laboratory, for example, by using energetic lasers. In the astronomical
case, each observation is unique and almost fixed in time, while shocks
produced in the laboratory and by numerical simulations can be reproduced,
and investigated in greater detail. The combined study of experimental and
computational results, as presented here, becomes a unique and powerful
probe to understanding radiative shock physics. Here we show the first
experiment on radiative shock performed at the PALS laser facility. The
shock is driven by a piston made from plastic and gold in a cell filled
with xenon at 0.2 bar. During the first 40 ns of the experiment, we have
traced the radiative precursor velocity, that is showing a strong decrease
at that stage. Three-dimensional (3D) numerical simulations, including
state-of-art opacities, seem to indicate that the slowing down of the
precursor is consistent with a radiative loss, induced by a transmission
coefficient of about 60% at the walls of the cell. We infer that such 3D
radiative effects are governed by the lateral extension of the shock wave,
by the value of the opacity, and by the reflection on the walls. Further
investigations will be required to quantify the relative importance of
each component on the shock properties.
Proton stopping in plasmas considering
e−–e− collisions
Authors: BARRIGA-CARRASCO M.D. , POTEKHIN A.Y.
Published: April 2008

The purpose of the present paper is to describe the effects of
electron-electron collisions on proton electronic stopping in plasmas of
any degeneracy. Plasma targets are considered fully ionized so electronic
stopping is only due to the free electrons. The stopping due to free
electrons is obtained from an exact quantum mechanical evaluation in the
random phase approximation, which takes into account the degeneracy of the
target plasma. The result is compared with common classical and degenerate
approximations. Differences are around 30% in some cases which can produce
bigger mistakes in further energy deposition and projectile range studies.
We focus our analysis on plasmas in the limit of weakly coupled plasmas
then electron-electron collisions have to be considered. Differences with
the same results without taking into account collisions are more than
50%.
Editorial from the Editor in Chief: Impact factors and open access
publishing
Authors: Hoffmann Dieter H.H.
Published: April 2008

The primary goal of Laser and Particle Beams as part of the
Cambridge University Press is the dissemination of knowledge in our
research field. How effective we are in this respect is not easy to
determine. But the impact factor published annually in June by Thomson
ISI® 2005 Journal Citation Reports (JCR), gives at least an indication
and a method to compare other journals in the field. In this respect,
Laser and Particle Beams is a journal with a very high ranking in
the field of applied physics, but it also compares very well to journals
in other field of physics. The impact factor of a journal gives an account
of how often an average paper in the journal is referred to, in a two year
time span after publication. The current impact factor of 2.59 is based on
an evaluation conducted in 2005 of Laser and Particle Beams
publications of 2003 and 2004. During the evaluation period (2005),
Laser and Particle Beams publications were cited about 1000
times. The topics that attracted most attention were Fast Ignition
(Deutsch, 2004; Mulser & Schneider, 2004a; Hora, 2004;
Mulser & Bauer, 2004b), Inertial
Fusion Targets (Borisenko et al., 2003), and Ion and Electron Acceleration in laser
plasma and Ultrashort Pulses (Shorokhov & Pukhov, 2004; Osman et al., 2004; Malka & Fritzler, 2004; Limpouch et al., 2004; Pegoraro et al., 2004). However, the editorial boards of Laser and
Particle Beams strongly encourage authors to submit their results in
High Energy Density Physics, the emerging field of Warm Dense Matter,
Pulsed Power and Accelerator Physics and Technology.
Difference between Hawking and Unruh radiation derived from studies
about pair production by lasers in vacuum
Authors: STAIT-GARDNER TIMOTHY , CASTILLO REYNALDO
Published: April 2008

Laser acceleration of electrons in laser fields of intensities above
1028 W/cm2 were found to be in the same range as
acceleration at the surface of black holes, where the laser intensities
are in the range of pair production in vacuum due to vacuum polarization.
The results in connection with the black holes arrived at similarities to
the Hawking and Unruh radiation. We present here results based on the
thermodynamics of the vacuum fluctuations that there is a difference
between Hawking and Unruh effects in connection with the Casimir effect in
view of the vacuum properties for laser produced pairs in a vacuum.
Thin plate effects in the Rayleigh–Taylor instability of
elastic solids
Authors: PIRIZ A. R. , LÓPEZ CELA J. J. , SERNA MORENO M. C. , TAHIR N. A. , HOFFMANN D. H. H.
Published: April 2008

(This article appeared in Volume 24, Number 2, Pages 275–282,
2006)

(This article appeared in Volume 24, Number 2, Pages 275–282,
2006)

Below is the correct Reference citation for Breil et al. (2005)

Breil, J., Hallo, L., Maire, P.H. & Olazabal-Loumé,
M. (2005). Hydrodynamic instabilities in axisymmetric geometry
self-similiar models and numerical simulations. Laser Part.
Beams.23, 155–160.
Simulation results for design and operation of CALUMA, a new low-cost humanoid robot
Authors: Nava Rodriguez Nestor Eduardo , Carbone Giuseppe , Ceccarelli Marco
Published: April 2008

This paper presents simulation results for basic operation of CALUMA (CAssino Low-cost hUMAnoid robot). The new humanoid robot CALUMA is described with its characteristics of low-cost design and easy-operation behavior. A CALUMA model in ADAMS environment has been elaborated. The CALUMA ADAMS model has been used for a dynamic simulation of robot operation. Three modes for the dynamic simulation have been studied, namely straight walking, walking with a grasped object in the hand, and lifting an object. The results of simulating those basic operations show the feasibility of the proposed design for CALUMA robot and validate its operation. Improvements have been illustrated in the design evolution for the robot structure and operation as suggested by simulation results.
Structural synthesis of maximally regular T3R2-type parallel robots via theory of linear transformations and evolutionary morphology
Authors: Gogu G.
Published: April 2008

The paper presents structural synthesis of maximally regular T3R2-type parallel robotic manipulators (PMs) with five degrees of freedom. The moving platform has three independent translations (T3) and two rotations (R2). A method is proposed for structural synthesis of maximally regular T3R2-type PMs based on the theory of linear transformations and evolutionary morphology. A one-to-one correspondence exists between the actuated joint velocity space and the external velocity space of the moving platform. The Jacobian matrix mapping the two vector spaces of maximally regular T3R2-type PMs presented in this paper is the 5×5 identity matrix throughout the entire workspace. The condition number and the determinant of the Jacobian matrix being equal to one, the manipulator performs very well with regard to force and motion transmission capabilities. Kinematic analysis of maximally regular parallel robots is trivial and no computation is required for real-time control. This paper presents in a unified approach the structural synthesis of PMs with five degrees of freedom with decoupled and uncoupled motions, along with the maximally regular solutions.
Systematic review of economic evidence on stroke rehabilitation services
Authors: Brady Bruce K. , McGahan Lynda , Skidmore Becky
Published: April 2008

Objectives: Given the resource-intensive nature of stroke rehabilitation, it is important that services be delivered in an evidence-based and cost-efficient manner. The objective of this review was to assess the evidence on the relative cost or cost-effectiveness of three rehabilitation services after stroke: stroke unit care versus care on another hospital ward, early supported discharge (ESD) services versus “usual care,” and community or home-based rehabilitation versus “usual care.”

Methods:A systematic literature review of cost analyses or economic evaluations was performed. Study characteristics and results (including mean total cost per patient) were summarized. The level of evidence concerning relative cost or cost-effectiveness for each service type was determined qualitatively.

Results:Fifteen studies met the inclusion criteria: three on stroke unit care, eight on ESD services, and four on community-based rehabilitation. All were classified as cost-consequences analysis or cost analysis. The time horizon was generally short (1 year or less). The comparators and the scope of costs varied between studies.

Conclusions:There was “some” evidence that the mean total cost per patient of rehabilitation in a stroke unit is comparable to care provided in another hospital ward. There is “moderate” evidence that ESD services provide care at modestly lower total costs than usual care for stroke patients with mild or moderate disability. There was “insufficient” evidence concerning the cost of community-based rehabilitation compared with usual care. Several methodological problems were encountered when analyzing the economic evidence.
Clinical- and cost-effectiveness of pegylated interferon alfa in the treatment of chronic hepatitis C: A systematic review and economic evaluation
Authors: Shepherd Jonathan , Brodin Håkan F. T. , Cave Carolyn Backer , Waugh Norman R. , Price Alison , Gabbay John
Published: April 2008

Objectives:To assess the clinical-effectiveness and cost-effectiveness of pegylated interferon alfa (2a and 2b) combined with ribavirin in previously untreated patients with moderate to severe chronic hepatitis C, compared with the current standard treatment, which is nonpegylated interferon alfa combined with ribavirin.

Methods:Systematic review and economic evaluation. A sensitive search strategy was applied to several electronic bibliographic databases. Relevant studies were critically appraised and meta-analyzed. A hypothetical cohort of 1,000 patients entered a Markov model and were followed up for a more than 30-year period to predict natural history, duration spent in each health state, and treatment costs.

Results:Two fully published Phase III randomized controlled trials were included. Methodological quality was generally good. Dual therapy with pegylated interferon was significantly more effective than nonpegylated dual therapy with a pooled sustained virological response rate (SVR) of 55 percent (95 percent confidence interval [CI], 52–58 percent) compared with 46 percent (95 percent CI, 43–49 percent). The pooled relative risk of remaining infected was 0.83 (95 percent CI, 0.76–0.91 percent). Genotype was the strongest predictor of outcome, with SVRs in patients with the more responsive genotypes 2 and 3 reaching up to 80 percent. The incremental cost per quality-adjusted life year (QALY) for pegylated dual therapy compared with nonpegylated dual therapy was £12,123. The cost per QALY remained under £30,000 for most patient subgroups and in sensitivity analyses.

Conclusions:Pegylated interferon is clinically effective, represents good value for the money, and is a significant advance in the treatment of this insidious disease.
Assessing the in-hospital survival benefits of intensive care
Authors: Shmueli Amir , Sprung Charles L.
Published: April 2008

Objectives:For an efficient and fair allocation of medical resources, one must know which patients benefit more from medical care. The objective of this study is to assess the differential survival benefits of a general intensive care unit (ICU) by acute diagnoses and by Acute Physiological and Chronic Health Evaluation (APACHE II) scores.

Methods:The sample included all patients triaged for admission to the Hadassah-Hebrew University Medical Center ICU during a 7-month period (n = 381). The potential effect of ICU on in-hospital survival was estimated by a bivariate (admission–survival) probit model, using crowding in the unit as the identifying variable, controlling for observable patients characteristics: age, sex, acute diagnoses, and APACHE II score. Using the estimates, the differential predicted survival benefits of ICU were calculated for selected general acute diagnoses and for different APACHE II scores.

Results:Adjusting for age, sex, and general acute diagnoses, the average potential survival benefit of ICU is 17 percentage points (pts). The benefit of ICU for patients with central nervous system problems, with sepsis, or with respiratory failure are higher than average (23 pts). Adjusting for APACHE II scores as well increases the estimated average potential benefit to 21 pts. Over the range of APACHE II scores, the highest benefit (38 pts of potential benefit) is attained for patients with scores around 22.

Conclusions:Survival benefits differ across diagnoses and APACHE II scores. Facing limited resources, admission policies should distinguish between survival probabilities (and survival maximization) and survival benefits (and maximization of ICU benefits). Actual referral and admission policies to the present ICU do not maximize the potential survival benefits of ICU resources.
Can health technologies be assessed using routine data?
Authors: Stevens Andrew J. , Raftery James , Roderick Paul
Published: April 2008

Objectives:The potential of routine data for health technology assessment (HTA) in the United Kingdom was assessed.

Methods:Compiled were a comprehensive list of routine databases, their classification according to data characteristics, literature review on their current use, and their comparison with key topics identified as priorities for HTA.

Results:Two hundred seventy health-care databases for England or the English regions were identified. Twenty-four included data on both health technology and patient health state. Eleven found some published use in effectiveness evaluation. Of 140 prioritized health technologies, only 22 could be identified in routine databases.

Conclusions:Routine data are plentiful but of limited use in HTA. The data sets usually do not include the effect of treatments. Coding is inadequate, and confidentiality regulations will make matters worse. Both need urgent attention.
International Master's Program in health technology assessment and management: Assessment of the first edition (2001–2003)
Authors: Lehoux Pascale , Battista Renaldo N. , Granados Alicia , Gallo Pedro , Tailliez Stéphanie , Coyle Doug , Marchetti Marco , Borgia Piero , Ricciardi Gualtiero
Published: April 2008

Background:Despite a clear call for greater input from health technology assessment (HTA) in the areas of clinical practice and policy making, there are currently very few formal training programs. The objectives of our Consortium were to (i) develop a master's level program in HTA, (ii) test its content with a group of Canadian and European students, and (iii) evaluate the Program's strengths and weaknesses.

Objectives:This study presents the results of our evaluation of the first edition of the Master's Program (2001–2003).

Methods:The evaluation relied on (i) a self-administered student questionnaire for each course (n = 142), (ii) interviews with students (n = 10), and (iii) interviews with internship supervisors (n = 5).

Results:A vast majority of students were satisfied with the course content and particularly appreciated the exercises and materials presented in an intensive format. However, they needed more systematic feedback from faculty members and recommended increasing the methodology content. The six key characteristics of the program are (i) flexible format adapted to the needs of skilled professionals, (ii) continuous interaction between HTA users and producers, (iii) international academic and professional collaboration, (iv) partnership with HTA agencies, (v) global approach to evidence-based methods and practices, and (vi) multidisciplinary approach.

Conclusions:Despite the numerous organizational barriers inherent to creating an international program and several areas for improvement in the Program itself, the Ulysses Project was successful in attaining its objectives. Because there is a growing need for human resources with special training in HTA, further efforts need to be devoted to strengthening the international research capacity in HTA.
Letter to the Editor
Authors: Weaver Lindell
Published: April 2008

To the Editor: I read with interest the research note by Saunders (2) in the Summer 2003 issue of International Journal of Technology Assessment in Health Care. Although this article was published in 2003 and stated to have been a thorough review of hyperbaric oxygen randomized clinical trials, our double-blind randomized control trial in acute carbon monoxide poisoning published in 2002 (4) was not mentioned, except as a blinded interim analysis (3). Our randomized clinical trial was considered a landmark study by Journal Watch–Emergency Medicine (1). Our clinical trial demonstrated a 46 percent reduction in cognitive sequelae at 6 weeks following poisoning, which was maintained 1 year after poisoning.
Lowering blood pressure to prevent myocardial infarction and stroke: A new preventive strategy
Authors: Law M. , Wald N. , Morris J.
Published: April 2008

Objectives: This study aimed to investigate
the screening performance of measuring blood pressure and other
variables in identifying those who willdevelop, or die from, ischemic
heart disease and stroke and too quantify by howmuch drugs that lower
blood pressure will reduce the risk of ischemic heart disease and stroke
in those designated “screen positive.”
What is the best imaging strategy for acute stroke?
Authors: Wardlaw J. M. , Keir S. L. , Seymour J. , Lewis S. , Sandercock P. A. G. , Dennis M. S. , Cairns J.
Published: April 2008

Objectives: The cost-effectiveness of
computed tomographic (CT) scanning after acute stroke was investigated
to assess the contribution of brain imaging to the diagnosis and
management of stroke and to estimate the costs, benefits, and risks of
different imaging strategies to provide data to inform national and
local policy on the use of brain imaging in stroke.
Effectiveness and efficiency of guideline dissemination and implementation strategies
Authors: Grimshaw J. M. , Thomas R. E. , MacLennan G. , Fraser C. , Ramsay C.R. , Vale L. , Whitty P. , Eccles M. P. , Matowe L. , Shirran L. , Wensing M. , Dijkstra R. , Donaldson C.
Published: April 2008

Objectives: A systematic review of the
effectiveness and costs of different guideline development,
dissemination, and implementation strategies wasundertaken. The resource
implications of these strategies was estimated, and a framework for
deciding when it is efficient to develop and introduce clinical
guidelines was developed.
Equity–efficiency trade-offs in health technology assessment
Authors: Williams Alan H. , Cookson Richard A.
Published: April 2008

Health technology assessment (HTA) currently focuses on efficiency, rather than equity, on the basis that its primary objective is to maximize population health. Yet a strict cost-effectiveness approach sometimes conflicts with important equity concerns, such as the reduction of socioeconomic health inequalities. Managing such equity–efficiency trade-offs on the basis of intuition is unsatisfactory in a democracy, as it arouses suspicions of special pleading and favoritism toward vested interests. Over the next few decades, therefore, decision making may progress through up to three further stages of development observed historically in other areas of resource allocation. Stage two involves case law, limited to principles distilled from precedent. Stage three involves codification, seeking to generalize these principles without specifying their relative weights. Finally, at stage four, quantitative trade-offs are incorporated into a formula. At stage four, deliberation centers on adjustments to the formula, which would then be applied impartially, transparently, and fair-mindedly to all future decisions. Methods already exist for valuing equity–efficiency trade-offs, based on established methodological principles for valuing trade-offs between different dimensions of health. Early findings indicate that the general public thinks that social class inequalities are more inequitable than those by smoking status, with inequalities between the sexes somewhere in between. Relative weights can be calculated from these data, although the data are not yet comprehensive enough to do this credibly for current policy purposes. In the mean time, the equity–efficiency trade-offs suggested by current decisions can be estimated using standard cost-effectiveness analysis. This is because every departure from a strict cost-effectiveness approach has an opportunity cost. The size of that opportunity cost is a test of how much weight a particular equity concern is deemed to merit.
Framework for describing and classifying decision-making systems using technology assessment to determine the reimbursement of health technologies (fourth hurdle systems)
Authors: Hutton John , McGrath Clare , Frybourg Jean-Marc , Tremblay Mike , Bramley-Harker Edward , Henshall Christopher
Published: April 2008

Objectives:Australia, Canada, and many European countries now use various forms of health technology assessment (HTA) in decision making regarding the reimbursement of drugs and other health technologies. To achieve a better understanding of the potential for use of HTA in this context, an analytical framework was developed to describe and classify existing fourth hurdle systems.

Methods:Based on a review of published literature, and official documentation, the key aspects of a fourth hurdle system were identified at two levels: policy implementation and individual technology decision. Characteristics of the systems were grouped under four main headings: constitution and governance, objectives, use of evidence and decision processes, and accountability. The comprehensiveness and relevance of this framework was assessed by an independent group of experts in HTA. A pilot study was undertaken, using only published sources, to test the feasibility of obtaining the information needed to complete the framework.

Results:The framework was found to be sufficiently broad to encompass all the issues of interest regarding the systems, but the proportion of information available from published sources was variable between sections of the framework and between countries, with average availability of 45 percent.

Conclusions:The analytical framework will help researchers and policy-makers in individual countries to understand their own systems and will allow some preliminary sharing of experience between countries. More experience of its application is needed to judge whether it will provide the basis for more formal comparison of systems and whether it will determine the appropriateness for particular decision contexts.
What influences the choice of assessment methods in health technology assessments? Statistical analysis of international health technology assessments from 1989 to 2002
Authors: Draborg Eva , Andersen Christian Kronborg
Published: April 2008

Objectives:Health technology assessment (HTA) has been used as input in decision making worldwide for more than 25 years. However, no uniform definition of HTA or agreement on assessment methods exists, leaving open the question of what influences the choice of assessment methods in HTAs. The objective of this study is to analyze statistically a possible relationship between methods of assessment used in practical HTAs, type of assessed technology, type of assessors, and year of publication.

Methods:A sample of 433 HTAs published by eleven leading institutions or agencies in nine countries was reviewed and analyzed by multiple logistic regression.

Results:The study shows that outsourcing of HTA reports to external partners is associated with a higher likelihood of using assessment methods, such as meta-analysis, surveys, economic evaluations, and randomized controlled trials; and with a lower likelihood of using assessment methods, such as literature reviews and “other methods.” The year of publication was statistically related to the inclusion of economic evaluations and shows a decreasing likelihood during the year span. The type of assessed technology was related to economic evaluations with a decreasing likelihood, to surveys, and to “other methods” with a decreasing likelihood when pharmaceuticals were the assessed type of technology.

Conclusions:During the period from 1989 to 2002, no major developments in assessment methods used in practical HTAs were shown statistically in a sample of 433 HTAs worldwide. Outsourcing to external assessors has a statistically significant influence on choice of assessment methods.
Improving the process of developing technical reports for health care decision-makers: Using the Theory of Constraints in the Evidence-Based Practice Centers
Authors: Patwardhan Meenal B. , Sarría-Santamera Antonio , Matchar David B.
Published: April 2008

Objectives:To apply the Theory of Constraints (TOC) to the Evidence-based Practice Center (EPC) process.

Methods:Participants in the EPC process were interviewed, and the technical contracting literature was reviewed. Undesirable effects (UDEs) that might occur in the EPC process were identified and, in a TOC Current Reality Tree (CRT), a fundamental UDE was selected and tracked back to potential root causes, focusing on the core “constraint.” The resulting draft CRT was presented at an EPC directors' meeting and finalized. From possible solutions obtained from interviews and literature, a Future Reality Tree (FRT) was constructed.

Results:Three UDEs were identified and thata report is not usedwas deemed fundamentally undesirable. Nine root causes were identified, and using the CRT, a core constraint emerged:EPC partner does not know how to conceptualize and articulate needs, objectives, and specifications. Two change strategies (“injections”) appeared to address the core constraint:establish an ongoing relationship between partners, EPC, and Agency for Healthcare Research and Quality early in the process, anduse a changes clause; in a FRT the injections lead to the positive outcome—the production of a successful EPCreport that meets partner needsand, therefore,will be used.

Conclusions:As with any complex enterprise, the EPC needs to engage in self-reflection and active improvement to maximize its value. The development of technical reports intended to inform decision making represents a complicated area, involving a network of interrelated processes. Using the TOC permitted us to understand process failures; results serve as a guide to improvement.
Health technology assessment in social care: A case study of randomized controlled trial retrieval
Authors: Bayliss Susan E. , Dretzke Janine
Published: April 2008

Objectives:The aim of this study was to evaluate the success of search strategies in retrieving key documents for a technology assessment report (TAR) on a social care topic.

Methods:This study measured the differential yield of relevant studies from various information sources and evaluated strategies in different databases, with particular reference to capturing randomized controlled trials (RCTs) as a study design.

Results:A combination of four major databases would have found all thirty-two key references. One database alone would have found 78 percent, with another two each locating 59 percent. Sixteen percent of the trials were unique references. In non–health care databases, more sensitive search strategies would have resulted in a higher yield of relevant studies, in part due to inconsistent indexing and in part to attempts to restrict searches to RCTs. Although additional terms could be used to increase the sensitivity of the original strategies, this raises the question of trading off time against exhaustiveness, given the greater number of irrelevant references likely to be retrieved.

Conclusions:A successful search for evidence on this social care topic would be possible using a combination of MEDLINE, EMBASE, the Cochrane Library and PsycINFO, supplemented by only limited use of supplementary databases. In areas such as social care where evidence-based research is not yet well established, attempts to replicate searches based on study design do not seem to be advisable, although this may be an area for future research.
Are we measuring what matters in health technology assessment of disease management? Systematic literature review
Authors: Steuten Lotte , Vrijhoef Bert , Severens Hans , van Merode Frits , Spreeuwenberg Cor
Published: April 2008

Objectives:An overview was produced of indicators currently used to assess disease management programs and, based on these findings, provide a framework regarding sets of indicators that should be used when taking the aims and types of disease management programs into account.

Methods:A systematic literature review was performed.

Results:Thirty-six studies met the inclusion criteria. It appeared that a link between aims of disease management and evaluated structure, process, as well as outcome indicators does not exist in a substantial part of published studies on disease management of diabetes and asthma/chronic obstructive pulmonary disease, especially when efficiency of care is concerned. Furthermore, structure indicators are largely missing from the evaluations, although these are of major importance for the interpretation of outcomes for purposes of decision-making. Efficiency of disease management is mainly evaluated by means ofprocessindicators; the use ofoutcomeindicators is less common. Within a framework, structure, process, and outcome indicators for effectiveness and efficiency are recommended for each type of disease management program.

Conclusions:The link between aims of disease management and evaluated structure, process, and outcome indicators does not exist in a substantial part of published studies on disease management. The added value of this study mainly lies in the development of a framework to guide the choice of indicators for health technology assessment of disease management.
Evaluation of the cost-effectiveness of drotrecogin alfa (activated) for the treatment of severe sepsis in the United Kingdom
Authors: Green Colin , Dinnes Jacqueline , Takeda Andrea L. , Cuthbertson Brian H.
Published: April 2008

Objectives:The aim of this study was to assess the cost-effectiveness of drotrecogin alfa (activated) compared with best supportive care in a UK cohort of adult intensive-care patients with severe sepsis.

Methods:A systematic review of evidence on the clinical- and cost-effectiveness of drotrecogin alfa (activated) was undertaken, and a decision-analytic model was developed to estimate the cost-effectiveness of treatment in the United Kingdom. Trial data from the Recombinant Human Activated Protein C Worldwide Evaluation in Severe Sepsis (PROWESS) study have been synthesized with other data, including UK data on severe sepsis, to estimate the costs and consequences of treatment over time.

Results:For patients with severe sepsis and multiple organ dysfunction, the estimates of cost per life year and cost per quality-adjusted life year (QALY) are £4,931 and £8,228, respectively. For patients with severe sepsis alone, the cost per life-year and cost per QALY are £5,495 and £9,161, respectively.

Conclusions:Whereas the therapeutic cost for drotrecogin alfa (activated) appears high (at around £5,000 per patient) and the potential impact on the provider budget is considerable, drotrecogin alfa (activated) is clinically effective, represents a cost-effective use of resources, and is a significant advance in the treatment of severe sepsis in patients requiring intensive care.
Cerebral protection devices for use during carotid artery angioplasty with stenting: A health technology assessment
Authors: Menon Devidas , Stafinski Tania
Published: April 2008

Objectives:This study sought to examine the safety, efficacy, and economic implications of the use of cerebral protection devices during carotid artery angioplasty and stenting (CAS) in high-risk patients with severe carotid artery disease (CAD).

Methods:A comprehensive search for peer- and non–peer-reviewed studies that compared carotid endarterectomy (CEA) or CAS without cerebral protection to CAS with cerebral protection and appeared in the English language literature between January 1990 and January 2005 was completed. Information from studies identified was extracted using a common data abstraction form and then critically appraised against published quality assessment criteria.

Results:Of the eight studies found, six provided information on technical or procedural success rates, with values ranging from 95.6 percent to 100 percent. Three of the four studies comparing groups of patients who received CAS with cerebral protection with those who received only CAS reported a non-statistically significantly higher 30-day incidence of death and stroke (major or minor) in the latter group. None of the three studies comparing CAS with cerebral protection to CEA demonstrated a statistically significant difference in the 30-day incidence of death, major stroke, or myocardial infarction between treatment groups. No economic analyses were found.

Conclusions:In high-risk patients with severe CAD, the evidence suggests that CAS with cerebral protection may offer a safe and efficacious alternative to CEA, reducing the risk of embolic peri-procedural complications associated with CAS to acceptable levels.
Principles for the design of the economic evaluation of COLOR II: An international clinical trial in surgery comparing laparoscopic and open surgery in rectal cancer
Authors: Björholt Ingela , Janson Martin , Jönsson Bengt , Haglind Eva
Published: April 2008

Objectives:The objective is to describe the principles for the design of the economic evaluation of COLOR II, a randomized, multi-country study comparing laparoscopic and open surgery for rectal cancer.

Methods:By using the experiences gained in a recent economic evaluation in colon cancer, where the same surgical techniques were compared, we could improve the method for identifying and measuring resource use items and also accommodate the use of data from the global study population.

Results:In the design of the study, the uncertainty in the resource-use variables was reduced by considering (i) what aspects drive each variable, (ii) what resource use is related to the intervention, (iii) how data from different countries affects the variable.

Conclusions:The aim was to refine the data collection so that the economic research question could be answered in the best possible way, given the circumstances in the clinical study. Thus, (i) some variables were treated as stochastic variables and others as deterministic variables, (ii) aggregate key cost-driving resource items were developed that corresponded to clinical events, and (iii) a surrogate variable was selected, instead of the “obvious variable”, to reduce the impact of confounding factors for one particular resource unit.
Joint project of the International Network of Agencies for Health Technology Assessment—Part 2: Managing the diffusion of positron emission tomography with health technology assessment
Authors: Adams Elizabeth J. , Almazán Cari , Mørland Berit , Bradbury Ian , King Richard , Rheinberger Paul
Published: April 2008

Objectives:Since 1997, members of the International Network of Agencies for Health Technology Assessment (INAHTA) have collaborated on a Joint Project to track the diffusion, evaluation, and clinical policy of positron emission tomography (PET). Part 2 of this updated Joint Project report summarizes HTA-based strategies for directing the clinical use of PET and a discussion on the value of HTA in managing the diffusion of high cost diagnostic technologies, which were presented at an INAHTA-sponsored workshop at the Health Technology Assessment International Annual Meeting in 2004 on strategies for managing high cost diagnostic technologies.

Methods:A summary of the workshop proceedings is presented.

Conclusions:Sharing assessment work, universal agreement in assessment conclusions, stakeholder input, and modeling techniques help manage the uncertainty in the evidence base while targeting clinical use of PET toward the most promising indications. Emphasis on HTA findings, linkage between financing of clinical PET and outcome evaluation, and targeted dissemination of scientific findings empower providers to reduce unnecessary utilization and contain costs within a quality improvement framework. Above all, a trustworthy source of HTA information and a process that is conducive to using scientific evidence as the basis for decision making are essential for managing the diffusion of complex and costly diagnostic technologies in patient care.
Recommendations in health technology assessments worldwide
Authors: Draborg Eva , Andersen Christian Kronborg
Published: April 2008

Objectives:The objective of this study is to analyze statistically the possible determinants and implications of including or not including recommendations in health technology assessments (HTAs).

Methods:A sample of 433 HTAs published by eleven leading institutions or agencies in nine countries was reviewed and analyzed statistically by multiple logistic regression.

Results:The extent of policy and research recommendations in HTAs varies greatly from country to country. The content and scope of HTAs have some impact on recommendations. Extensive assessment of economic and organizational aspects increases the likelihood of including policy recommendations. Extensive assessment of technological and patient aspects increases the likelihood of including research recommendations, whereas extensive focus on economic aspects is negatively related to research recommendations. The most striking result is that the use of external partners for assessment increases the likelihood of including research recommendations in HTAs but not policy recommendations.

Conclusions:HTA commissioners, agencies, institutions, and funding authorities need to be aware of the consequences of the choices they make in advance of assessing health technologies. Outsourcing HTA to external partners suggests a greater likelihood of being told that “more research is needed.” The scope and content of HTAs has an impact on the type of recommendations, and country-specific preferences are strong predictors of recommendations in HTAs.
Impact of CEDIT recommendations: An example of health technology assessment in a hospital network
Authors: Bodeau-Livinec Florence , Simon Emmanuelle , Montagnier-Petrissans Catherine , Joël Marie-Eve , Féry-Lemonnier Elisabeth
Published: April 2008

Objectives: The objective of this study is to assess the impact of CEDIT (French Committee for the Assessment and Dissemination of Technological Innovations) recommendations on the introduction of technological innovations within the AP-HP (Assistance Publique–Hôpitaux de Paris), the French hospital network to which this body is attached.

Methods: In 2002, a study based on semidirective interviews of fourteen people affected by these recommendations and a case study relating to thirteen recommendations issued between 1995 and 1998 were conducted.

Results: The CEDIT is very scientifically reputable among interviewees. There is generally widespread interest for the recommendations. They are used as decision-making tools by administrative staff and as negotiating instruments by doctors in their dealings with management. Based on the case study, ten of thirteen recommendations had an impact on the introduction of the technology in health establishments. One recommendation appears not to have had an impact. Furthermore, the impact of two technologies was impossible to assess.

Conclusions: This study highlights the significant impact of recommendations arising from a structure that is attached to a hospital network and the good match between CEDIT's objectives and its assignments.